1,052 research outputs found

    The value-added statement: An appeal for standardisation

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    Owing to the absence of accounting standards for the preparation of a value-added statement (VAS), a large variety of methods are used in financial statements. In this study the published value-added statements (PVAS) of companies listed on the JSE Securities Exchange during the period 1976-2005 have been standardised by the Graduate School of Business of the University of Stellenbosch (USB) in order to quantify the differences between the standardised VAS (SVAS) and the PVAS. These differences consist of the inclusion of items that do not belong in the VAS, items that are erroneously allocated among the distribution to stakeholders, and interpretation differences in whether a certain item forms part of the calculation of value added or the distribution thereof. The greatest difference quantified was the overstatement of the distribution to government that amounted to 54.4% of total differences. For users, including government, to properly calculate and compare the value added of different business entities, a standard for the preparation and presentation of VAS ought to be published. In the South African context the need of a precise measurement of each business entity's contribution to the growth of the national economy is relevant, and this need should also be addressed.Value added, Gross Domestic Product, South Africa, financial statements

    A Structure for Quasars

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    This paper proposes a simple, empirically derived, unifying structure for the inner regions of quasars. This structure is constructed to explain the broad absorption line (BAL) regions, the narrow `associated' ultraviolet and X-ray warm absorbers (NALs); and is also found to explain the broad emission line regions (BELR), and several scattering features, including a substantial fraction of the broad X-ray Iron-K emission line, and the bi-conical extended narrow emission line region (ENLR) structures seen on large kiloparsec scales in Seyfert images. Small extensions of the model to allow luminosity dependent changes in the structure may explain the UV and X-ray Baldwin effects and the greater prevalence of obscuration in low luminosity AGN.Comment: 35 pages, including 8 color figures (figures 4abc are big). Astrophysical Journal, in press. Expanded version of conference paper astro-ph/000516

    Ab-initio density-functional lattice-dynamics studies of ice

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    We present the results of first-principles computational studies of the dynamical properties of hexagonal ice using both the ab-initio pseudopotential method and the full-potential augmented plane-wave method. Properties obtained using both the generalized gradient approximation (GGA) and the meta-GGA in density-functional theory are compared. The lattice-dynamical properties of the structures are obtained using a finite-difference evaluation of the dynamical matrix and force-constant matrix from atomic forces. Phonon dispersion is evaluated by the direct determination of the force-constant matrix in supercells derived from the primitive molecule unit cells with the assumption that force constants are zero beyond the second molecular nearest neighbors. The k-dependent phonon frequencies are then obtained from the force-constant matrix and dispersion relations, and the Brillouin-zone integrated density of states is evaluated. The importance of phonon dispersion in the various regions of the phonon spectra is then assessed and compared to existing neutron-scattering data. Frozen-phonon calculations are used to compare phonon frequencies evaluated in both the GGA and meta-GGA

    A Spectroscopic Study of a Large Sample of Wolf-Rayet Galaxies

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    We analyze long-slit spectral observations of 39 Wolf-Rayet (WR) galaxies with heavy element mass fraction ranging over 2 orders of magnitude, from Zsun/50 to 2Zsun. Nearly all galaxies in our sample show broad WR emission in the blue region of the spectrum (the blue bump) consisting of an unresolved blend of N III 4640, C III 4650, C IV 4658 and He II 4686 emission lines. Broad C IV 5808 emission (the red bump) is detected in 30 galaxies. Additionally, weaker WR emission lines are identified, most often the N III 4512 and Si III 4565 lines, which have very rarely or never been seen and discussed before in WR galaxies. These emission features are characteristic of WN7-WN8 and WN9-WN11 stars respectively. We derive the numbers of early WC (WCE) and late WN (WNL) stars from the luminosities of the red and blue bumps, and the number of O stars from the luminosity of the Hbeta emission line. Additionally, we propose a new technique for deriving the numbers of WNL stars from the N III 4512 and Si III 4565 emission lines. This technique is potentially more precise than the blue bump method because it does not suffer from contamination of WCE and early WN (WNE) stars and nebular gaseous emission. The N(WR)/N(O+WR) ratio decreases with decreasing metallicity, in agreement with predictions of evolutionary synthesis models. The N(WC)/N(WN) ratios and the equivalent widths of the blue bump EW(4650) and of the red bump EW(5808) derived from observations are also in satisfactory agreement with theoretical predictions.Comment: 49 pages, 9 figures, to appear in Astrophys.

    X-ray Spectral Survey of WGACAT Quasars, II: Optical and Radio Properties of Quasars with Low Energy X-ray Cut-offs

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    We have selected quasars with X-ray colors suggestive of a low energy cut-off, from the ROSAT PSPC pointed archive. We examine the radio and optical properties of these 13 quasars. Five out of the seven quasars with good optical spectra show associated optical absorption lines, with two having high delta-v candidate systems. Two other cut-off quasars show reddening associated with the quasar. We conclude that absorption is highly likely to be the cause of the X-ray cut-offs, and that the absorbing material associated with the quasars, not intervening along the line-of-sight. The suggestion that Gigahertz Peaked Sources are associated with X-ray cut-offs remains unclear with this expanded sample.Comment: 17 pages, LaTeX, including 2 Tables and 1 figure. Ap.J. in pres

    River and maritime boundaries between South Africa and Namibia

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    The thesis explores four aspects of delimitation beginning with the terrestrial boundary..

    Communication, leadership and coordination failure

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    We investigate the limits of communication and leadership in avoiding coordination failure in minimum effort games. Our environment is challenging, with low benefits of coordination relative to the effort cost. We consider two leader types: cheap-talk leader-communicators who suggest an effort level, and first-mover leaders who lead by example. Both types of leadership have some ability to increase effort in groups with no history, but are insufficient in groups with a history of low effort. Using the strategy method for followers’ responses, we attribute the persistence of coordination failure to the presence of followers who do not follow the leader

    Ankle brachial index combined with Framingham risk score to predict cardiovascular events and mortality - A meta-analysis

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    CONTEXT: Prediction models to identify healthy individuals at high risk of cardiovascular disease have limited accuracy. A low ankle brachial index (ABI) is an indicator of atherosclerosis and has the potential to improve prediction. OBJECTIVE: To determine if the ABI provides information on the risk of cardiovascular events and mortality independently of the Framingham risk score (FRS) and can improve risk prediction. DATA SOURCES: Relevant studies were identified. A search of MEDLINE (1950 to February 2008) and EMBASE (1980 to February 2008) was conducted using common text words for the term ankle brachial index combined with text words and Medical Subject Headings to capture prospective cohort designs. Review of reference lists and conference proceedings, and correspondence with experts was conducted to identify additional published and unpublished studies. STUDY SELECTION: Studies were included if participants were derived from a general population, ABI was measured at baseline, and individuals were followed up to detect total and cardiovascular mortality. DATA EXTRACTION: Prespecified data on individuals in each selected study were extracted into a combined data set and an individual participant data meta-analysis was conducted on individuals who had no previous history of coronary heart disease. RESULTS: Sixteen population cohort studies fulfilling the inclusion criteria were included. During 480,325 person-years of follow-up of 24,955 men and 23,339 women, the risk of death by ABI had a reverse J-shaped distribution with a normal (low risk) ABI of 1.11 to 1.40. The 10-year cardiovascular mortality in men with a low ABI (< or = 0.90) was 18.7% (95% confidence interval [CI], 13.3%-24.1%) and with normal ABI (1.11-1.40) was 4.4% (95% CI, 3.2%-5.7%) (hazard ratio [HR], 4.2; 95% CI, 3.3-5.4). Corresponding mortalities in women were 12.6% (95% CI, 6.2%-19.0%) and 4.1% (95% CI, 2.2%-6.1%) (HR, 3.5; 95% CI, 2.4-5.1). The HRs remained elevated after adjusting for FRS (2.9 [95% CI, 2.3-3.7] for men vs 3.0 [95% CI, 2.0-4.4] for women). A low ABI (< or = 0.90) was associated with approximately twice the 10-year total mortality, cardiovascular mortality, and major coronary event rate compared with the overall rate in each FRS category. Inclusion of the ABI in cardiovascular risk stratification using the FRS would result in reclassification of the risk category and modification of treatment recommendations in approximately 19% of men and 36% of women. CONCLUSION: Measurement of the ABI may improve the accuracy of cardiovascular risk prediction beyond the FRS

    Clinical Outcomes in 3343 Children and Adults with Rheumatic Heart Disease from 14 Low and Middle Income Countries: 2-Year Follow-up of the Global Rheumatic Heart Disease Registry (the REMEDY study)

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    Background: There are few contemporary data on the mortality and morbidity associated with rheumatic heart disease or information on their predictors. We report the 2-year follow-up of individuals with rheumatic heart disease from 14 low- and middle-income countries in Africa and Asia. Methods: Between January 2010 and November 2012, we enrolled 3343 patients from 25 centers in 14 countries and followed them for 2 years to assess mortality, congestive heart failure, stroke or transient ischemic attack, recurrent acute rheumatic fever, and infective endocarditis. Results: Vital status at 24 months was known for 2960 (88.5%) patients. Two-thirds were female. Although patients were young (median age, 28 years; interquartile range, 18–40), the 2-year case fatality rate was high (500 deaths, 16.9%). Mortality rate was 116.3/1000 patient-years in the first year and 65.4/1000 patient-years in the second year. Median age at death was 28.7 years. Independent predictors of death were severe valve disease (hazard ratio [HR], 2.36; 95% confidence interval [CI], 1.80–3.11), congestive heart failure (HR, 2.16; 95% CI, 1.70–2.72), New York Heart Association functional class III/IV (HR, 1.67; 95% CI, 1.32–2.10), atrial fibrillation (HR, 1.40; 95% CI, 1.10–1.78), and older age (HR, 1.02; 95% CI, 1.01–1.02 per year increase) at enrollment. Postprimary education (HR, 0.67; 95% CI, 0.54–0.85) and female sex (HR, 0.65; 95% CI, 0.52–0.80) were associated with lower risk of death. Two hundred and four (6.9%) patients had new congestive heart failure (incidence, 38.42/1000 patient-years), 46 (1.6%) had a stroke or transient ischemic attack (8.45/1000 patient-years), 19 (0.6%) had recurrent acute rheumatic fever (3.49/1000 patient-years), and 20 (0.7%) had infective endocarditis (3.65/1000 patient-years). Previous stroke and older age were independent predictors of stroke/transient ischemic attack or systemic embolism. Patients from low- and lower-middle–income countries had significantly higher age- and sex-adjusted mortality than patients from upper-middle–income countries. Valve surgery was significantly more common in upper-middle–income than in lower-middle– or low-income countries. Conclusions: Patients with clinical rheumatic heart disease have high mortality and morbidity despite being young; those from low- and lower-middle–income countries had a poorer prognosis associated with advanced disease and low education. Programs focused on early detection and the treatment of clinical rheumatic heart disease are required to improve outcomes. </jats:sec
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