3,242 research outputs found
Prevalence of Otitis Media in Okada Community, Edo State, Nigeria
Aim. To determine the prevalence of otitis media in Okada, a rural community in Nigeria, and the effect of age and gender on its prevalence as well as susceptibility profile of the bacterial agents in the community.Material and Methods. Ear discharge from 500 (240 males and 260 females) patients with signs and symptoms of otitis media were processed to recover bacterial agents. Susceptibility test was performed on all bacterial isolates.
Results. Male gender was a significant (P = 0.011) risk factor for acquiring otitis media (male Vs female;
36.25% Vs 25.38%. OR = 1.671 95 CI = 1.139, 2.454). Age significantly (P < 0.0001) affected the
prevalence of otitis media with children within the age range of 0 – 5years having the highest prevalence
of 78.41%. Pseudomonas aeruginosa was the predominant bacteria isolate causing otitis media generally and in both gender. All bacterial isolates showed were poorly susceptible to the antibacterial agents used as less than 50 percent of any bacteria genera were susceptible to any antibacterial agent.Conclusion. An overall prevalence of 30.6% of bacteriologically proven otitis media was observed in this study. The prevalence were higher in males and in children 5 years and younger. Following the high
level resistance observed, rational use of antibacterial agents is advocated
Comparison of cube attacks over different vector spaces
We generalise the cube attack of Dinur and Shamir (and the similar AIDA attack of Vielhaber) to a more general higher order differentiation attack, by summing over an arbitrary subspace of the space of initialisation vectors. The Moebius transform can be used for efficiently examining all the subspaces of a big space, similar to the method used by Fouque and Vannet for the usual cube attack.
Secondly we propose replacing the Generalised Linearity Test proposed by Dinur and Shamir with a test based on higher order differentiation/Moebius transform. We show that the proposed test provides all the information provided by the Generalised Linearity Test, at the same computational cost. In addition, for functions that do not pass the linearity test it also provides, at no extra cost, an estimate of the degree of the function. This is useful for guiding the heuristics for the cube/AIDA attacks
Red and Black Tides: Quantitative Analysis of Water-Leaving Radiance and Perceived Color for Phytoplankton, Colored Dissolved Organic Matter, and Suspended Sediments
Using field measurements and quantitative modeling, we demonstrate that red coloration of the sea surface is not associated with any particular group of phytoplankton and is strongly dependent on the physiology of the human visual system. Red or brown surface waters can be produced by high concentrations of most types of algae, colored dissolved organic matter, or suspended sediment. Even though light reflected by red tides commonly peaks in the yellow spectral region (570–580 nm), human color perception requires consideration of the entire spectrum of light relative to receptors within the human eye. The color shift from green to red is not due to any special optical properties of the algae but results from an overlap in spectral response of the eye’s red and green cones (centered at 564 and 534 nm, respectively). The spectral peak in light reflected from dense algal blooms coincides with a critical hinge point in color vision (570–580 nm), where fine-scale shifts in the spectral shape of water-leaving radiance due to algal absorption and backscattering properties lead to pronounced variations in the observed color. Of the taxa considered, only Chlorophytes and Prochlorophytes lacked sufficient accessory pigments to produce a red tide. Chlorophyll fluorescence and enhanced near-infrared reflectance (the ‘‘red edge’’) contribute negligibly to the perceived color. Black water events are produced when water is highly absorbing but lacks backscattering constituents
Prevalence of malaria and anaemia among HIV infected patients in Benin City, Nigeria
Objective: To determine the prevalence of malaria and anaemia in
HIV-infected persons and the effect of age, gender and CD4+T cell
counts thereon.
Methods: Blood samples were collected from 491 patients (240
female) attending an out patient clinic. Malaria parasitaemia was diagnosed by microscopy while anaemia was defi ned as haemoglobin concentration <130g/L in males and <120g/L in females. The CD4 + T cell count was estimated by fl ow cytometry.Results: HIV infection was a risk factor for malaria infection(OR: 16.31; 95% CI: 7.41-35.87; p < 0.0001). CD4+T cell counts was equally a signifi cant risk factor in malaria infection among HIVinfected
patients (OR: 1.96; 95% CI: 1.28-3.02; p = 0.002). The prevalence of anaemia was signifi cantly affected by HIV-infection (OR: 25.12; 95% CI: 11.42-55.28; p < 0.0001) while age was not associated with increased risk of malaria infection (p=0.13).Conclusions: A prevalence of 46.0% of malaria infection among HIV-infected was observed. HIV-infected patients were more likely to develop malaria and anaemia, while CD4+T cell counts < 200cells/μL was associated with an increased risk of malaria infection
among HIV-infected. Age and gender did not affect the prevalence of malaria. HIV status should be considered early in the diagnostic evaluation of patients with suspected malaria and anaemia
Enhancing individual animal resilience to environmental disturbances to address low productivity in dairy cattle performing in sub-Saharan Africa
The current review examines potential solutions to enhance the sustainability and productivity of the dairy sector in sub-Saharan Africa (SSA) with an emphasis on breeding for resilience. Additionally, the paper explores various indicators for measuring resilience and provides insights into the data that can be utilized to quantify resilience in SSA’s dairy production systems. Dairy production contributes significantly to food and nutritional security and employment in SSA. However, besides the general lack of enabling policy and institutional environments, production is negatively affected by environmental challenges such as high temperatures and heat stress, diseases and parasites, unreliable rainfall patterns, shortages of feeds and forages and undue preference for taurine cattle breeds regardless of their poor adaptability to prevailing local conditions. Fostering the resilience capacity of dairy animals is imperative to combat climate-related adversities and maintain productivity. This can only be achieved if reliable and practical methods for quantifying and analyzing resilience in SSA are described and undertaken. This study has reviewed variance of deviations, root mean square of deviations, autocorrelation of deviations, skewness of deviations, slope of the reaction norm and its absolute value as possible indicators of resilience in SSA. While previous research has reported genetic variation and favorable correlations of these indicators with health, fitness, and fertility traits, their potential in SSA environments requires further investigation. Besides, labor- and cost-effective phenotypic data collection is essential for characterization of resilience using these indicators. Through this study, we propose frequently collected data on milk production traits, body fat-related traits, and activity patterns as suitable in the sub-Saharan Africa context. The African Asian Dairy Genetic Gains Project by the International Livestock Research Institute (ILRI) offers a valuable opportunity to collate data from diverse dairy systems in SSA for testing the potential of these indicators. Insights from this study are helpful in improving resilience of dairy animals in SSA, which would contribute to poverty alleviation, animal welfare improvement, and better preparedness in lieu of climate change in SSA.</p
Genes in the postgenomic era
We outline three very different concepts of the gene - 'instrumental', 'nominal', and 'postgenomic'. The instrumental gene has a critical role in the construction and interpretation of experiments in which the relationship between genotype and phenotype is explored via hybridization between organisms or directly between nucleic acid molecules. It also plays an important theoretical role in the foundations of disciplines such as quantitative genetics and population genetics. The nominal gene is a critical practical tool, allowing stable communication between bioscientists in a wide range of fields grounded in well-defined sequences of nucleotides, but this concept does not embody major theoretical insights into genome structure or function. The post-genomic gene embodies the continuing project of understanding how genome structure supports genome function, but with a deflationary picture of the gene as a structural unit. This final concept of the gene poses a significant challenge to conventional assumptions about the relationship between genome structure and function, and between genotype and phenotype
Higher order differentiation over finite fields with applications to generalising the cube attack
Higher order differentiation was introduced in a cryptographic context by Lai. Several attacks can be viewed in the context of higher order differentiations, amongst them the cube attack of Dinur and Shamir and the AIDA attack of Vielhaber. All of the above have been developed for the binary case. We examine differentiation in larger fields, starting with the field GF(p) of integers modulo a prime p, and apply these techniques to generalising the cube attack to GF(p). The crucial difference is that now the degree in each variable can be higher than one, and our proposed attack will differentiate several times with respect to each variable (unlike the classical cube attack and its larger field version described by Dinur and Shamir, both of which differentiate at most once with respect to each variable). Connections to the Moebius/Reed Muller Transform over GF(p) are also examined. Finally we describe differentiation over finite fields GF(ps) with ps elements and show that it can be reduced to differentiation over GF(p), so a cube attack over GF(ps) would be equivalent to cube attacks over GF(p)
Comparison of cube attacks over different vector spaces
We generalise the cube attack of Dinur and Shamir (and the similar AIDA attack of Vielhaber) to a more general higher order differentiation attack, by summing over an arbitrary subspace of the space of initialisation vectors. The Moebius transform can be used for efficiently examining all the subspaces of a big space, similar to the method used by Fouque and Vannet for the usual cube attack. Secondly we propose replacing the Generalised Linearity Test proposed by Dinur and Shamir with a test based on higher order differentiation/ Moebius transform. We show that the proposed test provides all the information provided by the Generalised Linearity Test, at the same computational cost. In addition, for functions that do not pass the linearity test it also provides, at no extra cost, an estimate of the degree of the function. This is useful for guiding the heuristics for the cube/AIDA attacks. Finally we implement our ideas and test them on the stream cipher Trivium
EPR study of radical intermediates from the oxidation of 6-ethoxy-2,2,4-trimethyl- and 6-ethoxy-2,2,4,8-tetramethyl-1,2-dihydroquinoline
The EPR spectra of 1,2-dihydro-6-ethoxy-2,2,4-trimethyl- and 1,2-dihydro-6-ethoxy-2,2,4,8-tetramethyl-quinolin-1-yl radicals were observed in heptane solution. The hyperfine splittings showed that this class of radical is extensively delocalised with significant spin density at C(8). Both radicals decayed by second-order processes, the rate constants being 5 × 106 and 4 × 102 dm3 mol–1 s–1, respectively at 273 K. The latter reaction is much slower because the 8-methyl substituent blocks the formation of the 1,8′-dimer. Both radicals reacted with oxygen to give the corresponding nitroxides, although reaction was very slow for the 8-methyl derivative. A mechanism is proposed to rationalise product formation from 1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline when used as an antioxidan
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