Holographic description of boundary gravitons in (3+1) dimensions

Gravity is uniquely situated in between classical topological field theories and standard local field theories. This can be seen in the the quasi-local nature of gravitational observables, but is nowhere more apparent than in gravity's holographic formulation. Holography holds promise for simplifying computations in quantum gravity. While holographic descriptions of three-dimensional spacetimes and of spacetimes with a negative cosmological constant are well-developed, a complete boundary description of zero curvature, four-dimensional spacetime is not currently available. Building on previous work in three-dimensions, we provide a new route to four-dimensional holography and its boundary gravitons. Using Regge calculus linearized around a flat Euclidean background with the topology of a solid hyper-torus, we obtain the effective action for a dual boundary theory which describes the dynamics of the boundary gravitons. Remarkably, in the continuum limit and at large radii this boundary theory is local and closely analogous to the corresponding result in three-dimensions. The boundary effective action has a degenerate kinetic term that leads to singularities in the one-loop partition function that are independent of the discretization. These results establish a rich boundary dynamics for four-dimensional flat holography.Comment: 43 pages, 3 figures, 1 tabl

Implementation of Internet Protocol Network Architecture for Effective bandwidth Allocation in a Multiparty, Multimedia Conferencing

Advances in multimedia technologies and development of overlay networks foster the opportunity for creating new value-added services over the current Internet. In this paper, a new service network architecture that supports multiparty multimedia conferencing applications, characteristics of which include multi-channel, high bandwidth and low delay tolerance has been proposed. The new service network architecture is built on an array of service nodes called Multiparty Processing Centers (MPCs) which constitute a service overlay network, serving as the infrastructure for multiparty conferencing, and are responsible for conferencing setup, media delivery and the provision of Quality of Service. In this paper, the main focus is on the bandwidth allocation management over the proposed service network. The analysis will determine the bandwidth demand for virtual links among the MPCs. Multimedia traffic is modeled as M/G/∞ input processes and divided into several classes, with the constraint that the aggregate effective bandwidth is within the link capacity times a prescribed utilization threshold

Genetic Diversity of Wild Rice (Oryza longistaminata) in Ghana

Oryza longistaminata is a wild rice taxon and an excellent source of genetic variation that remains largely unexploited. This study was conducted to understand the genetic diversity between and within O. longistaminata populations, collected from different geographic locations in Ghana. In this study, SSR markers were used to determine the intra-specific variability in O. longistaminata, and how the variation is partitioned within and between different populations. Analysis of molecular variance revealed high levels of polymorphism (95.9%) within the populations. The overall genetic diversity for all the loci in the six populations was high (Shannon's Information Index I = 0.579, Nei's unbiased expected heterozygosity, He = 0.405). Hierarchical partitioning also indicated a high genetic diversity between and within populations, with some level of relatedness between samples taken from the Savannah agroecological area. The high genetic diversity observed in this study offer a great opportunity for screening useful traits among the populations of O. longistaminata in Ghana for rice breeding programs

Molecular Based Survey of Pathogens Associated with Respiratory Disease Outbreaks in Broiler Chickens in Accra

Respiratory diseases in poultry are caused by a host of pathogens that act either singly or in association with each other. The clinical signs elicited by some poultry respiratory pathogens are similar and may confuse diagnostic efforts. Definitive diagnoses involving the use of sensitive, robust and rapid laboratory method are important for the identification and differentiation of specific agent(s) during infection. Our study aimed at identifying the involvement of Infectious Bronchitis Virus, Newcastle Disease Virus and Mycoplasma gallisepticum (MG) in outbreaks of respiratory diseases in chickens in the Ga-East district of Greater Accra using the Polymerase Chain Reaction technique (PCR). Twenty (20) trachea swabs were obtained from four chicken flocks (5 per flock) with acute respiratory diseases. RNA and DNA were extracted from each sample individually. The S1 glycoprotein gene, MgC2 gene and fusion protein gene of IBV, MG and NDV respectively, was individually target in a single tube PCR reaction. Amplicons were resolved on a 1% agarose gel stained with Ethidium bromide and visualized with a UV trans-illuminator. Twenty percent (20%) of samples tested negative to all three pathogens. IBV and NDV as single agents were detected in 40% and 20% of the samples respectively. Twenty percent (20%) of the samples were found to be co-infected with IBV and NDV. None of the samples tested positive to MG. IBV and NDV play major roles in outbreaks of respiratory diseases in commercial broiler chickens in Ga-East district of Accra. Keywords: Respiratory pathogens, Broilers, Ghana, Polymerase Chain Reactio

Evaluating the economic outcomes of the policy of fee exemption for maternal delivery care in Ghana

Background: The Government of Ghana’s fee exemption policy for delivery care introduced in September 2003, aimed at reducing financial barriers to using maternal services. This policy alsoaimed to increase the rate of skilled attendance at delivery, reduce maternal and perinatal mortality rates and contribute to reducing poverty. Objective: To evaluate the economic outcomes of the policy on households in Ghana. Methods: Central and Volta regions were selectedfor the study. In each region, six districts were selected. A two stage sampling approach was used to identify women for a household cost survey. A sample of 1500 women in Volta region (made up of 750 women each before and after the exemption policy) and 750 women after the policy was introduced in Central region. Outcome Measures: Household out-of-pocket payment for maternal delivery and catastrophic out-of-pocket health payments. Results: There was a statistically significant decrease in the mean out-of-pocket payments for caesarean section (CS) and normal delivery at health facilities after the introduction of the policy. The percentage decrease was highest for CS at 28.40% followed by normal delivery at 25.80%. The incidence of catastrophic out-of-pocket payments also fell. At lower thresholds, the incidence of catastrophic delivery payment was concentratedmore amongst the poor. For the poorest group (1st quintile) household out-of-pocket payments in excess of 2.5% of their pre-payment incomedropped from 54.54% of the households to 46.38% after the exemption policy. The policy had a more positive impact on the extreme poor than the poor. The richest households (5th quintile) had a declinein out-of-pocket payments of 21.51% while the poor households (1st quintile) had a 13.18% decline. Conclusions: The policy was beneficial to users of the service. However, the rich benefited more thanthe poor. There is need for proper targeting to identify the poorest of the poor before policies are implemented to ensure maximum benefit by thetarget group

Comparative study of proximate, minerals and fatty acid (as oleic) content of cooked and uncooked cow tripe consumed in Ghana.

Background: Meat and meat products such as the cow tripe are commonly eaten in Ghana, but their nutrient composition is not known and this affects evidenced based nutrition counseling and interventions. Objectives:The study was to compared the minerals, proximate and free fatty acid (FFA) (as oleic) composition of uncooked and cooked samples of cow tripe. Methods: Samples of cow tripewere obtained from the markets by purposive sampling which was later processed and analysed. The samples were chemically analysed to determine the nutrient content by using standard methods. Results were presented as means and standard deviations. The data from the uncooked and cooked tripe were compared using the Independent sample t-test. Results: The moisture content was significantly higher (p < 0.05) in the raw cow tripe than the cooked cow tripe. Energy, ash, fat and protein content were all significantly higher (p < 0.05) in cooked cow tripe than raw cow tripe. The carbohydrate content of raw cow tripe is not significantly higher (p > 0.05) than cooked cow tripe with a 100% change after cooking. No significant difference (p > 0.05) was found in the FFA (as oleic) content of the raw and cooked sample. Zinc content of cow tripe reduced after cooking by 99%. Phosphorus content was significantly higher when cooked(p < 0.05). After cooking also, there was a significant increase of copper in tripe (p < 0.05). Raw tripe recorded a very high iron content (app. 13.0 mg/100g), and did not decrease significantly after cooking. Conclusion: The study gave ample information on the proximate, oleic and mineralscomposition of raw and cooked cow tripe consumed in Ghana.The findings revealed that, cow tripe have considerable nutritional value,which can make significant impact in the nutrients intakes of individuals

Child vaccination in sub-Saharan Africa: Increasing coverage addresses inequalities.

BackgroundVaccines have substantially contributed to reducing morbidity and mortality among children, but inequality in coverage continues to persist. In this study, we aimed to examine inequalities in child vaccination coverage in sub-Saharan Africa.MethodsWe analysed Demographic and Health Survey data in 25 sub-Saharan African countries. We defined full vaccination coverage as a child who received one dose of bacille Calmette-Guérin vaccine (BCG), three doses of diphtheria, pertussis, and tetanus vaccine (DTP 3), three oral polio vaccine doses (OPV 3), and one dose of measles vaccine. We used the concentration index (CCI) to measure wealth-related inequality in full vaccination, incomplete vaccination, and zero-dose children within and between countries. We fitted a multilevel regression model to identify predictors of inequality in receipts of full vaccination.ResultsOverall, 56.5% (95% CI: 55.7% to 57.3%) of children received full vaccination, 35.1% (34.4% to 35.7%) had incomplete vaccination, while 8.4% (95% CI: 8.0% to 8.8%) of children remained unvaccinated. Full vaccination coverage across the 25 sub-Saharan African countries ranged from 24% in Guinea to 93% in Rwanda. We found pro-rich inequality in full vaccination coverage in 23 countries, except for Gambia and Namibia, where we found pro-poor vaccination coverage. Countries with lower vaccination coverage had higher inequalities suggesting pro-rich coverage, while inequality in unvaccinated children was disproportionately concentrated among disadvantaged subgroups. Four or more antenatal care contracts, childbirth at health facility, improved maternal education, higher household wealth, and frequently listening to the radio increased vaccine uptake.ConclusionsContinued efforts to improve access to vaccination services are required in sub-Saharan Africa. Improving vaccination coverage and reducing inequalities requires enhancing access to quality services that are accessible, affordable, and acceptable to all. Vaccination programs should target critical social determinants of health and address barriers to better maternal health-seeking behaviour