bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dependence of the transference of a reduced eye on frequency of light*
Authors: Evans T. , Harris W. F. 
Published: October 2016

In Gaussian optics the transference is a matrix that is a complete representation of the effects of the system on a ray traversing it. Almost all of the familiar optical properties of the system, such asrefractive error and power of the system, can be calculated from the transference. Because of the central importance of the transference it is useful to have some idea of how it depends on the frequencyof light. This paper examines the simplest model eye, the reduced eye. The dependence of the transference is calculated in terms of both frequency andwavelength of light and both dependencies are displayed graphically. The principal matrix logarithms are also calculated and displayed graphically. Chromatic difference in refractive compensation, power and ametropia are obtained for the reduced eye from the transferences. (S Afr Optom 2011 70(4) 149-155)
Ocular manifestations of mitochondrial disease
Authors: Mathebula S. D. 
Published: October 2016

Mitochondrial disease caused by mutations in mitochondrial DNA is recognized as one of the most common causes of inherited neurological disease. Neuro-ophthalmic manifestations are a common feature of mitochondrial disease. Optic atrophy causing central visual loss is the dominant feature of mitochondrial DNA diseases. Nystagmus is also encountered in mitochondrial disease.Although optometrists are not involved with the management of mitochondrial disease, they are likely to see more patients with this disease. Oph-thalmic examination forms part of the clinical assessment of mitochondrial disease. Mitochondrial disease should be suspected in any patient with unexplained optic neuropathy, ophthalmoplegia, pigmentary retinopathy or retrochiasmal visual loss. Despite considerable advances in the under-standing of mitochondrial genetics and the patho-genesis of mtDNA diseases, no effective treatment options are currently available for patients withmitochondrial dysfunction. (S Afr Optom 201271(1) 46-50)
Global and local contributions to surface curva- ture of healthy corneas
Authors: Rubin Alan , Mathebula Solani David 
Published: October 2016

This paper demonstrates for several healthy eyes the application of a simple model to understanding local and global contributions to short-term variation in anterior and posterior corneal curvature. Multiple axial anterior and posterior corneal radii and central corneal thicknesses for the right eyes of 10 young subjects were determined over time using a rotating Scheimpflug camera (Oculus Pentacam). The axial radii were transformed to corneal powers, and also to curvatures that were referred to a mid-corneal surface such that local and global contributions to short-term variation could be analyzed quantitatively.When variation of the anterior and posterior corneal surfaces of several healthy eyes are studied in terms of curvatures (rather than powers) it is the posterior surfaces that are more variable withthe global or macroscopic rather than local effects dominating. (Harris and Gillan found the same for an eye with mild keratoconus.) This finding is opposite to that when variation is considered in terms of dioptric power where the anterior corneal surface usually appears more variable. Possible reasons for this finding includes firstly that the posterior corneal surface has to be measured through the air-tear interface and anterior corneal surface,and thus some uncertainty in measurements of the posterior surface may relate to this limitation. Secondly, no attempt was made here to mathematically align the multiple surfaces as determined per eye and thus we cannot be certain that precisely the same central corneal region was measured each time.Investigators need to carefully consider whether they are more interested in the optical or physical nature of variation in surfaces such as the cornea since studies of the optical effects require theanalysis to be performed in terms of dioptric powers and symmetric dioptric power space whereas studies of physical variation in the topography of the cornea and the possible reasons for such variability require the application of surface curvaturesin surface curvature space. This paper describes the application and significance of both methods to facilitate understanding of short-term variation of the human cornea. It does not, however, attempt to make any definite claims as to what factors (seeabove) may be major contributors to such variability, and this complicated but interesting research issue requires further clarification. (S Afr Optom 2012 71(4) 146-158)
A retrospective analysis of eye injuries in rural KwaZulu-Natal, South Africa
Authors: Sukati V. N. , Hansraj R. 
Published: October 2016

Purpose: To provide epidemiological data on ocular injuries among patients utilising two provincial hospital eye care clinics in rural KwaZulu-Natal, South Africa.Methods: Record cards of 440 ocular injured patients seen at two selected rural provincial hospitals over a period of four years were reviewed.Results: More males (68.9%) had eye injuries than females (31.1%). The Black population (97.7%) had a higher prevalence of ocular injuries than other race groups. Young patients between 21 and 30 years old incurred more ocular injuries (31.4%) than other age groups. Open globe injuries were more frequent (56.1%) than closed globe injuries (43.9%). Blunt trauma/contusion (36.4%) was the most frequent type of injury (36.4%). Solid objects (53.4%) were responsible for more than half of the injuries followed by assaults (28.2%). The majority of the eye injuries (54.5%) occurred at home. There was a reduction in visual acuity of 37.7% of the subjects following treatment.Conclusion: Ocular trauma is a relatively common health problem in rural KwaZulu-Natal and is significantly more common among the male and Black population. (S Afr Optom 2012 71(4) 159-165)
Lipid composition of human meibum
Authors: Schnetler R. , Gillan W. D. H. , Koorsen G. 
Published: October 2016

The structure and function of meibomian gland lipids in the tear film are highly complex. Evidence shows that the precorneal tear film consists of discrete layers: the inner mucin layer, the middle aqueous layer and the outer lipid layer. In this review we focus on the outer, biphasic lipid layer of the tear film which consists of a ‘thick’ outer, non-polar layer and a ‘thin’ inner, polar layer. We discuss the main composition of the polar and non-polar lipids within meibum (wax esters, cholesteryl esters, mono-, di- and tri-acylglycerols, ceramides, phospholipids et cetera). We address the composition of meibomian lipids in subjects suffering from various ocular diseases in comparison with the composition in healthy individuals. Further analysis is needed to determine whether a correlation exists between the etiology of various ocular diseases and the fluctuation on the lipids as well as to establish whether or not tear lipid analysis can be used as a diagnostic tool.
The validity and reliability of iridology in the diagnosis of previous acute appendicitis as evi-denced by appendectomy
Authors: Frank L. , Ferreira J.T. , Pellow J. 
Published: October 2016

Iridology is defined as a photographic science that identifies pathological and functional changes within organs via biomicroscopic iris assessment for aberrant lines, spots, and discolourations. According to iridology, the iris does not reflect changes during anaesthesia, due to the drugs inhibitory effects on nerves impulses, and in cases of organ removal, it reflects the pre-surgical condition.The profession of Homoeopathy is frequently associated with iridology and in a recent survey (2009) investigating the perceptions of Masters of Technology graduates in Homoeopathy of University of Johannesburg, iridology was highly regarded as a potential additional skill requirement for assessing the health status of the patient.This study investigated the reliability of iridology in the diagnosis of previous acute appendicitis, as evidenced by appendectomy. A total of 60 participants took part in the study. Thirty of the 60 participants had an appendectomy due to acute appendicitis, and 30 had had no prior history of appendicitis. Each participant’s right iris was documented by photography with the use of a non-mydriatic retinal camera that was reset for photographing the iris. The photographs were then randomized by an external person and no identifying data made available to the three raters. The raters included the researcher, who had little experience in iridology and two highly experienced practising iridologists. Data was obtained from the analyses of the photographs wherein the presence or absence of lesions (implying acute appendicitis) was indicated by the raters. None of the three raters was able to show a significant success rate in identifying correctly the people with a previous history of acute appendicitis and resultant appendectomies from those who had no previous history of acute appendicitis. Therefore the outcome of this study indicated an outcome that was subject to chance.The null hypothesis that states that appendectomy due to acute appendicitis does not manifest in corresponding lesions in the iris, is supported. It is in the opinion of the researchers that the association of iridology with homoeopathic practice may harm the credibility of the profession and that further research on iridology is needed to disprove this conviction. (S Afr Optom 2013 72(3) 127-132)
Prevalence and causes of visual impairment and blindness among adults with diabetes mellitus aged 40 years and older receiving treatment at government health facilities in the Mopani District, South Africa
Authors: Mabaso R.G. , Oduntan O.A. 
Published: October 2016

This article presents part of the findings of a study conducted to assess the prevalence and causes of visual impairment (VI) and blindness among adults with diabetes mellitus (DM) receiving treatment at the government health facilities in the Mopani District, South Africa. This health facility-based cross-sectional study was conducted among 225 Black South African diabetics (161 females and 64 males) aged 40-90 years (mean= 61.50 ± 10.49) years at seven different health care facilities. All the participants were examined for VI using an auto-refractor, pinhole disc, an ophthalmoscope, and a logMAR chart. Visual impairment was defined as visual acuity (VA) of worse than 6/9.5 but better and equal to 3/60, and blindness as VA of worse than 3/60 to no light perception. The prevalence of uncompensated VI and blindness in the right eyes was 70.6 and 3.6%, respectively. In the left eyes, the prevalence was 72 and 3.1% for VI and blindness respectively. The prevalence of blindness remained the same after optical compensation. The leading causes of uncompensated VI and blindness in both eyes were uncorrected refractive error (RE) (49.5%), cataract (24.7%), diabetic retinopathy (3.8%) and glaucoma (2.2%). Following optical compensation, the prevalence of compensated VI and blindness in the right eyes was 41.3 and 3.6%, respectively and in the left eyes, the prevalence was 42.2 and 3.1%, respectively. Uncompensated RE and cataract were the common causes of VI and blindness in this sample. The socio-economic status of this population might have contributed to these findings. These results indicate the need for affordable vision examination and spectacles provision as well as cataract surgery services in this population.
Near vision anomalies in Black high school children in Empangeni, South Africa: A pilot study
Authors: Wajuihian Sam O. , Hansraj Rekha 
Published: October 2016

Background: The ability to read efficiently and comfortably is important in the intellectual development and academic performance of a child. Some children experience difficulties when reading due to symptoms related to near vision anomalies. Aim: To explore the feasibility of conducting a large study to determine the prevalence, distribution and characteristics of near vision anomalies in high school children in Empangeni, South Africa. Methods: The study was a cross sectional descriptive pilot study designed to provide preliminary data on prevalence, distribution and characteristics of near vision anomalies in a sample of high school-children in South Africa. Study participants comprised 65 Black children (30 males and 35 females), ages ranged between 13 and 19 years with a mean age and standard deviation of 17 ± 1.43 years. The visual functions evaluated and the techniques used included visual acuity (LogMAR acuity chart), refractive error (autorefractor and subjective refraction), heterophoria (von Graefe), near point of convergence (push-in-to-double), amplitude of accommodation (push-in-to-blur) accommodation facility (± 2 D flipper lenses), relative accommodation, accommodation response (monocular estimation method) and fusional vergences (step vergence with prism bars). Possible associations between symptoms and near vision anomalies were explored using a 20-point symptoms questionnaire. Results: Prevalence estimates were: Myopia 4.8%, hyperopia 1.6% and astigmatism 1.6%. For accommodative anomalies, 1.6% had accommodative insufficiency while 1.6% had accommodative infacility. For convergence anomalies, 3.2% had receded near point of convergence, 16% had low suspect convergence insufficiency, no participant had high suspect convergence insufficiency, 1.6% had definite convergence insufficiency and 3.2% had convergence excess. Female participants reported more symptoms than the males and the association between clinical measures and symptoms were not remarkable. Conclusion: Although the overall prevalence of near vision anomalies was low, convergence anomalies were found to be more prevalent than refractive and accommodative anomalies. Symptoms were not significantly associated with near vision anomalies. Overall, the pilot project reveals that it is feasible to conduct the study on a large scale with minor modifications. Identification and referrals for near vision anomalies are important steps towards diagnosis and treatment which will minimize discomfort with reading and subsequent poor performance which may be associated with such anomalies.
Mirror symmetry of higher order aberrations between right and left eyes
Authors: Oberholzer M. , Gillan W.D.H. , Rubin A. 
Published: October 2016

Introduction: There is evidence that certain measures of visual function show some type of relationship between right and left eyes in the same individual. Similarly, particular ocular maladies may be related, or be symmetric, in the right and left eyes of the same person. There is also evidence to suggest that certain relationships do not exist between eyes in an individual. For example, diseases such as glaucoma are often asymmetric in their progression in the two eyes of an afflicted individual. Inter-ocular mirror symmetry between right and left eyes, when considering ocular wave-front aberrations (WAs), has been shown to exist by some authors. This study investigates whether mirror symmetry of high order aberrations (HOAs) exists between the right and left eyes in a cohort of South African subjects. Method: Third to 5th order Zernike coefficients (HOAs) were measured on both eyes of 66 subjects (132 eyes) using a Zywave aberrometer. A total of 15 Zernike coefficients for each eye were obtained. Mirror symmetry was investigated using correlation coefficients between the various measurements obtained from each eye. Results: Pearson product-moment correlation coefficients provide evidence that the majority of the 15 Zernike coefficients suggest the presence of mirror symmetry between right and left eyes of the 66 subjects. Examples of individual scatter plots comparing right and left eyes are presented. Conclusion: The results of this study suggest that mirror symmetry exists in the HOAs obtained from the 132 eyes measured and thus care should be exercised when combining eyes of individuals for analysis. (S Afr Optom 2013 73(1) 39-44)
Heavy snow loads in Finnish forests respond regionally asymmetrically to projected climate change
Authors: Lehtonen Ilari , Kämäräinen Matti , Gregow Hilppa , Venäläinen Ari , Peltola Heli 
Published: October 2016

Abstract. This study examined the impacts of projected climate change on heavy snow loads on Finnish forests, where snow-induced forest damage occurs frequently. For snow-load calculations, we used daily data from five global climate models under representative concentration pathway (RCP) scenarios RCP4.5 and RCP8.5, statistically downscaled onto a high-resolution grid using a quantile-mapping method. Our results suggest that projected climate warming results in regionally asymmetric response on heavy snow loads in Finnish forests. In eastern and northern Finland, the annual maximum snow loads on tree crowns were projected to increase during the present century, as opposed to southern and western parts of the country. The change was rather similar both for heavy rime loads and wet snow loads, as well as for frozen snow loads. Only the heaviest dry snow loads were projected to decrease over almost the whole of Finland. Our results are aligned with previous snowfall projections, typically indicating increasing heavy snowfalls over the areas with mean temperature below −8 °C. In spite of some uncertainties related to our results, we conclude that the risk for snow-induced forest damage is likely to increase in the future in the eastern and northern parts of Finland, i.e. in the areas experiencing the coldest winters in the country. The increase is partly due to the increase in wet snow hazards but also due to more favourable conditions for rime accumulation in a future climate that is more humid but still cold enough.
The new portfolio of global precipitation data products of the Global Precipitation Climatology Centre suitable to assess and quantify the global water cycle and resources
Authors: Schneider Udo , Ziese Markus , Meyer-Christoffer Anja , Finger Peter , Rustemeier Elke , Becker Andreas 
Published: October 2016

Abstract. Precipitation plays an important role in the global energy and water cycle. Accurate knowledge of precipitation amounts reaching the land surface is of special importance for fresh water assessment and management related to land use, agriculture and hydrology, incl. risk reduction of flood and drought. High interest in long-term precipitation analyses arises from the needs to assess climate change and its impacts on all spatial scales. In this framework, the Global Precipitation Climatology Centre (GPCC) has been established in 1989 on request of the World Meteorological Organization (WMO). It is operated by Deutscher Wetterdienst (DWD, National Meteorological Service of Germany) as a German contribution to the World Climate Research Programme (WCRP). This paper provides information on the most recent update of GPCC's gridded data product portfolio including example use cases.
Measuring the Magic of Public Space. Le Piazze di Roma
Authors: Garau Pietro 
Published: October 2016

<p>The concept of public space, and particularly of civic public space, is certainly a constitutive element of Italy’s urban culture. The design and spatial configuration of public spaces have always been a synthesis between deeply rooted models and political functions (the <em>piazza, </em>the <em>palazzo, </em>the church, the civic buildings), and of local circumstances and design inspiration. Hence the fascination of the <em>piazza: </em>while all <em>piazze </em>perform similar functions, they take very different spatial and architectural characteristics, thus adding to the variety and the “magic”, as it were, of public space experience.<br />The main purpose of this article is to celebrate the piazza as the core symbol of public space magic. In doing so, I set a modest linguistic goal: to discourage non-Italian speaking piazza fans from using the plural “piazzas” and to impose the Italian “piazze”. As to the success of this endeavour, only future will tell.</p>
LC-MS/MS Validation of a Residue Analysis Method for Penicillin G and Its Metabolites in Commercial Orange Juice
Authors: Aldeek Fadi , Canzani Daniele , Standland Matthew , Hammack Walter , Cook Jo-Marie , Crosswhite Mark R , Gerard Ghislain 
Published: October 2016

Abstract
Florida citrus depends on a breakthrough in the fight against citrus greening disease. Of the antibiotics used to treatthis disease, penicillin G has been one of the most effective. Because orange fruit grown in the state of Florida are mainly used to produce orange juice, we have validated an ultra-HPLC tandem MS method to screen for penicillin G and its metabolites (penillic and penilloic acids) at the chemical residue level after treatment. In this method, three spike levels (0.25, 1, and 20 ng/g) were tested in triplicate. Absolute recoveries for penillic and penilloic acids were 60–75% depending on the matrix used, whereas corrected recoveries of penicillin G using an isotopically labeled internal standard were ~100%. Two product ion transitions per analyte were required for identification, which contributes to a high degree of selectivity.
Anmeldelser
Authors: Simonsen Karen-Margrethe 
Published: October 2016

Karen-Margrethe Simonsen: "Det politiske menneske - Anmeldelse af Christian Dahl: Tragedie og bystat. Om fællesskab og konflikt i Athens dramatiske kultur"Martin Zerlang: "Lys over Afrika - Anmeldelse af Frits Andersen: Det mørke kontinent? Afrikabilleder i europæiske fortællinger om Congo" Reviews