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

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

Grain quality characteristics of imported rice in Ghana: Implications for breeding for consumer-preferred varieties

ABSTRACTRice is the fastest growing food source in Ghana. The country, however, imports about 70 per cent of its rice requirement due to low volumes of production and poor grain quality of domestic rice compared to imported ones.  In the study, 10 popular imported rice brands on the Ghanaian market were characterised for grain quality traits including grain dimensions, apparent amylose content, gelatinisation temperature, paste viscosity properties, and aroma using physiochemical properties and DNA markers. The rice brands came from Asia and the USA. The rice type from Asia was found to be Jasmine-styled aromatic long grained with low amylose content and gelatinisation temperature, whereas those of USA were conventional long grain with intermediate amylose content and gelatinisation temperature.  These findings were confirmed through DNA marker analyses, with the rice types from Asia and the USA revealing the presence of the TAC and GCC of the waxy gene SNP haplotypes, respectively. The implication for rice breeding in Ghana is discussed.Original scientific paper. Received 29 Oct. 14; revised 03 Aug 15

A comparison of outcomes between finger and pulp replantation/revascularization in a single centre

Background: Supermicrosurgery has allowed the replantation/revascularization of the pulp, but how does this currently compare with more proximal digit replantation/revascularization? Methods: In a retrospective case study over a 5-year period at our institute, a total of 21 patients (n = 21) had either finger or pulp replantation-revascularization posttrauma. All pulp replants had a single-vessel anastomosis viz., “artery-to-artery” or “artery-to-vein” only, with venous outflow dependent on the skin-shave technique, while more proximal replants had both arterial and venous anastomoses. Age, sex, ischemic time, handedness, smoker status, and injury-replant interval were compared between the two groups, with all procedures performed by a single surgeon. The outcome parameters studied were length of hospital stay, timeline for wound healing, viability, and functional outcomes. Results: Our patients consisted of 18 men and three women, of which 14.3% were smokers and 85.7% were right-handed. There were 11 finger replantation/revascularizations (n = 11) versus 10 pulp replantation/revascularizations (n = 10). The average age of digit replantation/revascularization patients was 44.8 years compared with 26.4 years in pulp replantation/revascularization patients (Student t test, P = 0.04). Mean ischemia time in digital replants was 67 minutes versus 32.3 minutes in pulp replantation/revascularization (Student t test, P = 0.056). Digital replantation/revascularization was viable in 72% of cases versus a 90% viability in the pulp subcohort. Conclusions: In our patient cohort, pulp replantation/revascularizations produced better postoperative viability. Where supermicrosurgery expertise is available, pulp replantation/revascularization should be considered a worthwhile option when compared with digital replantation/revascularization

The Ghana Renal Registry – a first annual report

There are few data on the treatment of kidney disease in sub-Saharan Africa and no formal reports of kidney replacement therapy (KRT) in Ghana. We report data from the newly established Ghana Renal Registry on the prevalence, causes, and modality of treatment of kidney disease in Ghana. Using the web-based data capture system of the African Renal Registry, data were obtained for patients who had KRT in Ghana between January and December 2017. A total of 201 patients started KRT, giving an incidence rate of 6.9 per million population (pmp). There were 687 patients on KRT, a prevalence rate of 23.6 pmp. The median age of prevalent patients was 45.5 years and 63.6% were male. Hypertensive kidney disease was the most common primary kidney disease, reported in 39.9%. The overwhelming majority of patients (96.2%) were treated with haemodialysis, 3.5% had a kidney transplant, and only two were on continuous ambulatory peritoneal dialysis. The incidence and prevalence of KRTtreated kidney failure in Ghana is low, and the patients are younger than those on KRT in high- and upper-middleincome countries. The major cause of kidney failure is hypertensive kidney disease and the vast majority of the patients are treated with haemodialysis