601 research outputs found

    Experimental estimation of challenge of a natural population of Glossina palpalis palpalis R-D (Diptera:Glossinidae) on cattle in the southern Guinea Savanna, Nigeria

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    The challenge posed by Glossina palpalis palpalis Robineau-Desvoidy 1830 to cattle was studied in a riverine forest of Manchok, Kaduna State, Nigeria. The challenge was estimated indirectly from entomological parameters using the number of flies biting the host and the proportion of flies that are potentially infective. Trypanosome infection rates of 26% and 24.3% were recorded in flies sampled from several sites in the dry and wet seasons. From the 134 flies that landed to bite, it was estimated that each animal received an estimated 11 and 15 mean bites per day in the dry and wet season respectively out of which approximately 3 and 4 harbour infections. This means that each animal host received an estimated total infective bite of about 15 (range 0.5-4.1/hr) and 19 (range 0.9-6.6/hr) during the dry and wet seasons, equivalent to 2.96 and 3.8 infective bites per day. Of the estimated infective bites, 12.6 and 2.2 were due to T. vivax Ziemann 1905 and T. congolense Boaden 1904 received during the dry season while 17.3 and 1.5 were received during the wet season. Activity of flies started at 09.00hr during the wet season and one hour later during the dry season. For both seasons, diurnal activity was less pronounced in the early morning (06.00-11.00hr) than mid (11.00-15.00hr) and late afternoon (15.00-18.00hr), and so was the number of potentially infective bites. The number of potentially infective flies feeding per day (06.00-18.00hr) was higher and more consistent during the wet season than in the dry season but the difference was not significant (P>0.50).The results suggest a high tsetse challenge in the area which is exacerbated by several factors including the synchronized activity of the flies and grazing herds, frequency of visit to riverine habitats of the vector and duration of contact between vector and host. Key words: Tsetse fly challenge, Trypanosoma vivax, T. congolense, cattle, Nigeri

    Seasonal variation of mixed layer depth in the north Arabian Sea

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    The Arabian Sea is unique due to the extremes in atmospheric forcing that lead to the semi-annual seasonal changes. The reversing winds of summer and winter monsoon induce the variation in the characteristics of mixed layer depth. The importance of mixed layer depth is recognized in studying the biological productivity in the ocean. In this paper variability of mixed layer depth in the north Arabian Sea have been discussed. The study is based on the data collected under North Arabian Sea Environment and Ecosystem Research (NASEER) program. The results of the study indicate that there is a significant variation in the mixed layer depth from summer to winter monsoon as well as coast to offshore

    Pseudo-unitary symmetry and the Gaussian pseudo-unitary ensemble of random matrices

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    Employing the currently discussed notion of pseudo-Hermiticity, we define a pseudo-unitary group. Further, we develop a random matrix theory which is invariant under such a group and call this ensemble of pseudo-Hermitian random matrices as the pseudo-unitary ensemble. We obtain exact results for the nearest-neighbour level spacing distribution for (2 X 2) PT-symmetric Hamiltonian matrices which has a novel form, s log (1/s) near zero spacing. This shows a level repulsion in marked distinction with an algebraic form in the Wigner surmise. We believe that this paves way for a description of varied phenomena in two-dimensional statistical mechanics, quantum chromodynamics, and so on.Comment: 9 pages, 2 figures, LaTeX, submitted to the Physical Review Letters on August 20, 200

    A re-evaluation of geographical distribution of charcoal rot on sunflower crop in various agroecological zones of Pakistan

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    A countrywide survey was conducted to update the status of charcoal rot on sunflower crop in Pakistan. During survey, charcoal rot was observed as a serious threat to sunflower. The areas like Bahawalpur, Rahim Yar Khan and Sahiwal which were reported disease free in 1996, showed occurrence of the disease but Sahiwal showed high incidence and severity in 1999. Distribution of the disease in Sindh, Punjab and NWFP provinces was 85, 83 and 48% respectively. Among Provinces NWFP showed highest incidence57%, and Punjab exhibited highest severity 2.62 according to 0-5 severity rating scale. Continuous increasing trend of charcoal rot is alarming for farmers and authorities engaged in sunflower business

    A Comparative Study of COVID-19 Vaccine Acceptability and its Determinants among Urban and Rural Community Residents in Ogun State

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    Background: The success of any COVID-19 vaccination programme will depend on public willingness to receive the vaccination. This is important to  tailor public health messaging appropriately. This study aimed to determine and compare COVID-19 vaccine acceptability and factors influencing it  among rural and urban community members in Ogun State.Methods: The study was a comparative cross-sectional study. Multistage sampling technique was utilized to select 404 and 396 adult residents from  the urban and rural communities, respectively. Data collection was by structured interviewer-administered questionnaire. Descriptive and  inferential statistics were done. Level of significance was set at p<5%.Results: More respondents in urban area 186 (46.0%) were willing to accept COVID-19 vaccine compared to rural respondents 90 (22.7%) (p<0.001). Acceptance that COVID-19 is real (AOR=2.98; 95%CI=1.61-5.51 p<0.001) versus (AOR=2.17; 95CI=1.06- 4.44 p=0.035) predicted acceptability in both  urban and rural areas, respectively. In urban area, being a male (AOR=1.58; 95%CI=1.02-2.44 p=0.041) while in rural area, completion of  immunization (AOR=3.47; 95%CI=1.79-6.72 p<0.001) and fair perceived risk of contracting COVID-19 (AOR=3.05; 95CI:1.55-6.01 p= 0.001) were predictors of acceptability.Conclusion: The study showed there was overall poor acceptability of COVID-19 vaccine among urban and rural residents. Urban residents were  more likely to accept the vaccines compared to rural residents. Therefore, government should do more in terms of health education and promotion  for a right attitude to COVID-19 vaccination

    Treatment of chronic hepatitis C in patients unresponsive to interferon. Interest of re-treatment combining interferon induction therapy and ribavirin (a multicenter pilot study)

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    Aim About 45% of patients with chronic hepatitis C are unresponsive to the present reference treatment combining pegelated interferon plus ribavirin; before pegylated interferon was available the non-response rate was around 60%. This open multicenter pilot study, initiated before pegylated interferon became available, was designed to evaluate, in patients unresponsive to interferon monotherapy, the rate of biological and virological response and side-effects of the ribivirin- alpha 2b interferon combination. Methods The combination protocol was ribavirin (1 to 1.2 g/d) plus alpha 2b interferon at induction doses (9 MU/d the first week; 4.5 MU/d the eleven following weeks; 3 MU/2 days the 36 following weeks). Results Among the 27 included patients, 17 (63%) were viremia-negative (PCR) after 12 weeks of treatment, 9 (33%) were complete responders (undetectable viremia and normal transaminases) at the end of treatment (48 weeks) and of follow-up (72 weeks). Patients with non-1, non-4 genotypes who derived full benefit from this therapeutic strategy (6/7 (86%) were complete responders: 4/5 with genotype 3 and 2/2 with genotype 5). Quality-of-life was impaired during treatment, especially during the first 12 weeks of high-dose interferon therapy. Conclusion While waiting for new therapeutic possibilities, these good results suggest interferon induction at the beginning of treatment remains a valid option

    High Precision Ionization Chamber for Relative Intensity Monitoring of Synchrotron Radiation

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    A single channel, high precision ionization chamber has been built for monitoring the relative intensity of X-rays in the energy range above 5 keV. It can be used in experiments, such as EXAFS, where simultaneous high precision monitoring of the relative intensity during the actual experiment is required. In this paper the construction of the chamber and its performance during test measurements with an X-ray tube are presented.Comment: 10 pages, 8 figure

    The Majorana neutrino masses, neutrinoless double beta decay and nuclear matrix elements

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    The effective Majorana neutrino mass is evaluated by using the latest results of neutrino oscillation experiments. The problems of the neutrino mass spectrum,absolute mass scale of neutrinos and the effect of CP phases are addressed. A connection to the next generation of the neutrinoless double beta decay (0nbb-decay) experiments is discussed. The calculations are performed for 76Ge, 100Mo, 136Xe and 130Te by using the advantage of recently evaluated nuclear matrix elements with significantly reduced theoretical uncertainty. An importance of observation of the 0nbb-decay of several nuclei is stressed.Comment: 29 pages, 5 figures, EXO (10 t) experiment considere
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