254 research outputs found

    MEASURING AND ALLOCATING PORTFOLIO RISK CAPITAL IN THE REAL WORLD: PRACTICAL APPLICATION OF VALUE-AT-RISK AND EXPECTED SHORTFALL

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    Financial risk professionals are constantly interested in the risk capital allocation especially when dealing with management of portfolios under their control. This paper seeks to investigate two major risk measures namely the Value-at-Risk (VaR) and Expected Shortfall (ES) in dealing with the risk capital allocation problem. Data from the London Stock exchange was used for this study. Assuming no dividends payment, the Geometric Brownian motion (Black-Scholes Model) and a fair per-unit capital allocation principle were applied to ascertain the coherence of the two considered risk measures within a two year time horizon. It is evident from the results that stock with high mean rate of log returns and low volatility turns to have a lower fair per unit capital allocation of risk in any selected portfolio. Results of stocks with the least quantified risk (in pence) of all considered portfolios in this paper were Portfolio I (Mining: BLT - 926), Portfolio II (Media: PSON - 175), Portfolio III (Financial services: SDRC - 459), Portfolio IV (Bank: STAN - 739) and Portfolio V (FTSE 100 top 10 Companies: BATS - 1021) respectively. Keywords:   Coherent Risk Capital Allocation Value-at-Risk Expected Shortfal

    Ownership Rights and Investment in Agricultural Land in Ghana: A Gender Analysis

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    This paper examines the relationship between ownership rights and investment in agricultural land from a gender perspective in Ghana, using the Two-Stage Conditional Maximum Likelihood estimation technique and data from the Ghana Household Asset Survey. The results indicate that investment in agricultural lands is generally low in Ghana and tends to occur mostly in agricultural lands owned by men suggesting its inability to enhance tenure security. Furthermore, investment in agricultural lands owned by men is associated with a wider range of ownership rights. However, the same cannot be said about agricultural land owned by women as investments in their land do not significantly improve their rights to the land. Except for economic rights that appear to have a significant negative association with investments in agricultural lands owned by women, all other rights have no significant relationship with investments in agricultural lands owned by both men and women. There is a positive relationship between age and ownership rights for men suggesting that the youth may have challenges securing their tenure. We recommend the strengthening of the current land administration projects to enhance tenure security. Policies that will support the growing of perennial trees, construction of farmhouses and irrigation should be put in place by the government to encourage men to undertake such investments as they tend to improve ownership rights of agricultural lands. More should also be done to secure the ownership rights of the youth if the government wants them to engage in agriculture

    Hydrogen Cyanide Accumulation and Transformations in Non-polluted Salt Marsh Sediments

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    While cyanide is known to be produced by many organisms, including plants, bacteria, algae, fungi and some animals, it is generally thought that high levels of cyanide in aquatic systems require anthropogenic sources. Here, we report accumulation of relatively high levels of cyanide in non-polluted salt marsh sediments (up to 230 μmol kg[superscript −1]). Concentrations of free cyanide up to 1.92 μmol L[superscript −1], which are toxic to aquatic life, were detected in the pore-waters. Concentration of total (free and complexed) cyanide in the pore-waters was up to 6.94 μmol L[superscript −1]. Free cyanide, which is released to the marsh sediments, is attributed to processes associated with decomposition of cord grass, Spartina alterniflora, roots and possibly from other sources. This cyanide is rapidly complexed with iron and adsorbed on sedimentary organic matter. The ultimate cyanide sink is, however, associated with formation of thiocyanate by reaction with products of sulfide oxidation by Fe(III) minerals, especially polysulfides. The formation of thiocyanate by this pathway detoxifies two poisonous compounds, polysulfides and hydrogen cyanide, preventing release of free hydrogen cyanide from salt marsh sediments into overlying water or air

    Mortality from external causes in Africa and Asia: evidence from INDEPTH Health and Demographic Surveillance System Sites.

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    BACKGROUND: Mortality from external causes, of all kinds, is an important component of overall mortality on a global basis. However, these deaths, like others in Africa and Asia, are often not counted or documented on an individual basis. Overviews of the state of external cause mortality in Africa and Asia are therefore based on uncertain information. The INDEPTH Network maintains longitudinal surveillance, including cause of death, at population sites across Africa and Asia, which offers important opportunities to document external cause mortality at the population level across a range of settings. OBJECTIVE: To describe patterns of mortality from external causes at INDEPTH Network sites across Africa and Asia, according to the WHO 2012 verbal autopsy (VA) cause categories. DESIGN: All deaths at INDEPTH sites are routinely registered and followed up with VA interviews. For this study, VA archives were transformed into the WHO 2012 VA standard format and processed using the InterVA-4 model to assign cause of death. Routine surveillance data also provide person-time denominators for mortality rates. RESULTS: A total of 5,884 deaths due to external causes were documented over 11,828,253 person-years. Approximately one-quarter of those deaths were to children younger than 15 years. Causes of death were dominated by childhood drowning in Bangladesh, and by transport-related deaths and intentional injuries elsewhere. Detailed mortality rates are presented by cause of death, age group, and sex. CONCLUSIONS: The patterns of external cause mortality found here generally corresponded with expectations and other sources of information, but they fill some important gaps in population-based mortality data. They provide an important source of information to inform potentially preventive intervention designs

    Comparative studies on the structure of an upland African stream ecosystem

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    Upland stream systems have been extensively investigated in Europe, North America and Australasia and many of the central ideas concerning their function are based on these systems. One central paradigm, the river continuum concept is ultimately derived from those North American streams whose catchments remain forested with native vegetation. Streams of the tropics may or may not fit the model. They have been little studied. The Amani Nature Reserve in the East Usambara Mountains of north-eastern Tanzania offers an opportunity to bring these naturally forested systems to the attention of the ecological community. This article describes a comparison made between two lengths of the River Dodwe in this area. The work was carried out by a group of postgraduate students from eighteen European and African countries with advice from five staff members, as part of a course organised by the Tropical Biology Association. Rigorous efforts were made to standardise techniques, in a situation where equipment and laboratory facilities were very basic, through a management structure and deliberate allocation of work to specialists in each area.The article offers a summary of invertebrate communities found in the stream and its biomass. Crabs seem to be the key organism in both sections of the streams

    The relationship between the perception of distributed leadership in secondary schools and teachers' and teacher leaders' job satisfaction and organizational commitment

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    This study investigates the relation between distributed leadership, the cohesion of the leadership team, participative decision-making, context variables, and the organizational commitment and job satisfaction of teachers and teacher leaders. A questionnaire was administered to teachers and teacher leaders (n=1770) from 46 large secondary schools. Multiple regression analyses and path analyses revealed that the study variables explained significant variance in organizational commitment. The degree of explained variance for job satisfaction was considerably lower compared to organizational commitment. Most striking was that the cohesion of the leadership team and the amount of leadership support was strongly related to organizational commitment, and indirectly to job satisfaction. Decentralization of leadership functions was weakly related to organizational commitment and job satisfaction

    Adult non-communicable disease mortality in Africa and Asia: evidence from INDEPTH Health and Demographic Surveillance System sites.

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    BACKGROUND: Mortality from non-communicable diseases (NCDs) is a major global issue, as other categories of mortality have diminished and life expectancy has increased. The World Health Organization's Member States have called for a 25% reduction in premature NCD mortality by 2025, which can only be achieved by substantial reductions in risk factors and improvements in the management of chronic conditions. A high burden of NCD mortality among much older people, who have survived other hazards, is inevitable. The INDEPTH Network collects detailed individual data within defined Health and Demographic Surveillance sites. By registering deaths and carrying out verbal autopsies to determine cause of death across many such sites, using standardised methods, the Network seeks to generate population-based mortality statistics that are not otherwise available. OBJECTIVE: To describe patterns of adult NCD mortality from INDEPTH Network sites across Africa and Asia, according to the WHO 2012 verbal autopsy (VA) cause categories, with separate consideration of premature (15-64 years) and older (65+ years) NCD mortality. DESIGN: All adult deaths at INDEPTH sites are routinely registered and followed up with VA interviews. For this study, VA archives were transformed into the WHO 2012 VA standard format and processed using the InterVA-4 model to assign cause of death. Routine surveillance data also provide person-time denominators for mortality rates. RESULTS: A total of 80,726 adult (over 15 years) deaths were documented over 7,423,497 person-years of observation. NCDs were attributed as the cause for 35.6% of these deaths. Slightly less than half of adult NCD deaths occurred in the 15-64 age group. Detailed results are presented by age and sex for leading causes of NCD mortality. Per-site rates of NCD mortality were significantly correlated with rates of HIV/AIDS-related mortality. CONCLUSIONS: These findings present important evidence on the distribution of NCD mortality across a wide range of African and Asian settings. This comes against a background of global concern about the burden of NCD mortality, especially among adults aged under 70, and provides an important baseline for future work

    A Randomized, Double-Blind, Placebo-Controlled, Dose-Ranging Trial of Tafenoquine for Weekly Prophylaxis against \u3ci\u3ePlasmodium falciparum\u3c/i\u3e

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    Tafenoquine is a promising new 8-aminoquinoline drug that may be useful for malaria prophylaxis in nonpregnant persons with normal glucose-6-phosphate dehydrogenase (G6PD) function. A randomized, doubleblind, placebo-controlled chemoprophylaxis trial was conducted with adult residents of northern Ghana to determine the minimum effective weekly dose of tafenoquine for the prevention of infection by Plasmodium falciparum. The primary end point was a positive malaria blood smear result during the 13 weeks of study drug coverage. Relative to the placebo, all 4 tafenoquine dosages demonstrated significant protection against P. falciparum infection: for 25 mg/week, protective efficacy was 32% (95% confidence interval [CI], 20%–43%); for 50 mg/week, 84% (95% CI, 75%–91%); for 100 mg/week, 87% (95% CI, 78%–93%); and for 200 mg/week, 86% (95% CI, 76%–92%). The mefloquine dosage of 250 mg/week also demonstrated significant protection against P. falciparum infection (protective efficacy, 86%; 95% CI, 72%–93%). There was little difference between study groups in the adverse events reported, and there was no evidence of a relationship between tafenoquine dosage and reports of physical complaints or the occurrence of abnormal laboratory parameters. Tafenoquine dosages of 50, 100, and 200 mg/week were safe, well tolerated, and effective against P. falciparum infection in this study population

    Four challenges in the field of alternative, radical and citizens’ media research

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    In January 1994 the Zapatista movement in southern Mexico inaugurated a new era of media use for dissent. Since that time, an array of dissenting collectives and individuals have appropriated media technologies in order to make their voices heard or to articulate alternative identities. From Zapatista media to the Arab Spring, social movements throughout the world are taking over, hybridizing, recycling, and adapting media technologies. This new era poses a new set of challenges for academics and researchers in the field of Communication for Social Change (CfSC). Based on examples from Mexico, Lebanon, and Colombia, this article highlights and discusses four such research challenges: accounting for historical context; acknowledging the complexity of communication processes; anchoring analysis in a political economy of information and communication technologies; and positioning new research in relation to existing knowledge and literature within the field of communication and social change.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Can changes in malaria transmission intensity explain prolonged protection and contribute to high protective efficacy of intermittent preventive treatment for malaria in infants?

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    BACKGROUND: Intermittent preventive (or presumptive) treatment of infants (IPTi), the administration of a curative anti-malarial dose to infants whether or not they are known to be infected, is being considered as a new strategy for malaria control. Five of the six trials using sulphadoxine-pyrimethamine (SP) for IPTi showed protective efficacies (PEs) against clinical malaria ranging from 20.1 - 33.3% whilst one, the Ifakara study, showed a protective efficacy of 58.6%. MATERIALS AND METHODS: The possible mechanisms that could explain the differences in the reported PE of IPTi were examined by comparing output from a mathematical model to data from the six published IPTi trials. RESULTS: Under stable transmission, the PE of IPTi predicted by the model was comparable with the observed PEs in all but the Ifakara study (ratio of the mean predicted PE to that observed was 1.02, range 0.39 - 1.59). When a reduction in the incidence of infection during the study was included in the model, the predicted PE of IPTi increased and extended into the second year of life, as observed in the Ifakara study. CONCLUSION: A decrease in malaria transmission during the study period may explain part of the difference in observed PEs of IPTi between sites and the extended period of protection into the second year of life observed in the Ifakara study. This finding of continued benefit of interventions in settings of decreasing transmission may explain why rebound of clinical malaria was absent in the large scale trials of insecticide-treated bed nets
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