846 research outputs found

    Methods of Available Potassium Assessment in Selected Soils of Kwara State, Nigeria

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    Responses to potassium (K) by potted Sorghum (Sorghum bicolor) were determined in soils taken from four Local Government Areas in Kwara State and regressed with K extracted with five laboratory methods. Results showed that without K application, dry-matter yields were relatively high and responses to 15 kg, 30 kg and 60 kg K ha-1 were negative and not significant in the soils derived from basement complex and sandstones. When dry matter yields without K application were less than 9.00 g/pot, there were no significant responses to K application and responses were significant only when they were more than 9%. Potassium extracted with N NH4OAc pH 7.0 gave the best indication of dry matter yields when K was not applied, with the equation, Y = 0.005X + 3.1902, r = 0.1622. Significant responses were obtained in soil testing with less than 15 kg K ha-1 with this method. Furthermore, K extracted with hot N HNO3 was almost equal with a higher value in virtually all soils to exchangeable K extracted with N NH4OAc and could be used in place of this extractant as it also accounts for the replenishable form of K in soil.Keywords: A-value, extractants, K status, % K response, Sorghum, uptak

    The effects of nitrogen and phosphorus deficiencies and nitrite addition on the lipid content of Chlorella vulgaris (Chlorophyceae)

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    The effect of 50% N, 100% N, 50% N plus 50% P and 50% P deficiencies and nitrite addition were treated on Chlorella vulgaris (Chlorophyceae) was studied in laboratory conditions with the aim to determine the effects of the deficient nutrient and different nitrogen sources on lipid and protein contents. Proteinand lipid values of the biomass were found as 50.8 and 12.29% for the control group, 20.3 and 17.5% for 50% N(-), 13.01 and 35.6% for 100% N(-), 21.37 and 20.5% for 50% N(-) and 50% P(-), 38.16 and 16.7% for 50% P(-) and 41.03 and 13.04% for the nitrite group that was added. The highest lipid content was recorded with the culture to which 100% N(-) was treated with 0.18 g/L dry-weight.Key words: Chlorella vulgaris, lipid, nitrogen and phosphorus deficiencies, nitrite

    Quasimonoenergetic electron beam generation by using a pinholelike collimator in a self-modulated laser wakefield acceleration

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    A relativistic electron bunch with a large charge (>2 nC) was produced from a self-modulated laser wakefield acceleration configuration. For this experiment, an intense laser beam with a peak power of 2 TW and a duration of 700 fs was focused in a supersonic He gas jet, and relativistic high-energy electrons were observed from the strong laser-plasma interaction. By passing the electron bunch through a small pinholelike collimator, we could generate a quasimonoenergetic high-energy electron beam, in which electrons within a cone angle of 0.25 mrad (f/70) were selected. The beam clearly showed a narrow-energy-spread behavior with a central energy of 4.3 MeV and a charge of 200 pC. The acceleration gradient was estimated to be about 30 GeV/m. Particle-in-cell simulations were performed for comparison study and the result shows that both the experimental and simulation results are in good agreement and the electron trapping is initiated by the slow beat wave of the Raman backward wave and the incident laser pulse.open181

    What are the drivers of recurrent cholera transmission in Nigeria? Evidence from a scoping review

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    Background: The 2018 cholera outbreak in Nigeria affected over half of the states in the country, and was characterised by high attack and case fatality rates. The country continues to record cholera cases and related deaths to date. However, there is a dearth of evidence on context-specific drivers and their operational mechanisms in mediating recurrent cholera transmission in Nigeria. This study therefore aimed to fill this important research gap, with a view to informing the design and implementation of appropriate preventive and control measures. / Methods: Four bibliographic literature sources (CINAHL (Plus with full text), Web of Science, Google Scholar and PubMed), and one journal (African Journals Online) were searched to retrieve documents relating to cholera transmission in Nigeria. Titles and abstracts of the identified documents were screened according to a predefined study protocol. Data extraction and bibliometric analysis of all eligible documents were conducted, which was followed by thematic and systematic analyses. / Results: Forty-five documents met the inclusion criteria and were included in the final analysis. The majority of the documents were peer-reviewed journal articles (89%) and conducted predominantly in the context of cholera epidemics (64%). The narrative analysis indicates that social, biological, environmental and climatic, health systems, and a combination of two or more factors appear to drive cholera transmission in Nigeria. Regarding operational dynamics, a substantial number of the identified drivers appear to be functionally interdependent of each other. / Conclusion: The drivers of recurring cholera transmission in Nigeria are diverse but functionally interdependent; thus, underlining the importance of adopting a multi-sectoral approach for cholera prevention and control

    The ansamycin antibiotic, rifamycin SV, inhibits BCL6 transcriptional repression and forms a complex with the BCL6-BTB/POZ domain

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    BCL6 is a transcriptional repressor that is over-expressed due to chromosomal translocations, or other abnormalities, in ~40% of diffuse large B-cell lymphoma. BCL6 interacts with co-repressor, SMRT, and this is essential for its role in lymphomas. Peptide or small molecule inhibitors, which prevent the association of SMRT with BCL6, inhibit transcriptional repression and cause apoptosis of lymphoma cells in vitro and in vivo. In order to discover compounds, which have the potential to be developed into BCL6 inhibitors, we screened a natural product library. The ansamycin antibiotic, rifamycin SV, inhibited BCL6 transcriptional repression and NMR spectroscopy confirmed a direct interaction between rifamycin SV and BCL6. To further determine the characteristics of compounds binding to BCL6-POZ we analyzed four other members of this family and showed that rifabutin, bound most strongly. An X-ray crystal structure of the rifabutin-BCL6 complex revealed that rifabutin occupies a partly non-polar pocket making interactions with tyrosine58, asparagine21 and arginine24 of the BCL6-POZ domain. Importantly these residues are also important for the interaction of BLC6 with SMRT. This work demonstrates a unique approach to developing a structure activity relationship for a compound that will form the basis of a therapeutically useful BCL6 inhibitor

    Using irregularly spaced current peaks to generatean isolated attosecond X-ray pulse in free-electron lasers

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    A method is proposed to generate an isolated attosecond X-ray pulse in free-electron lasers, using irregularly spaced current peaks induced in an electron beam through interaction with an intense short-pulse optical laser. In comparison with a similar scheme proposed in a previous paper, the irregular arrangement of current peaks significantly improves the contrast between the main and satellite pulses, enhances the attainable peak power and simplifies the accelerator layout. Three different methods are proposed for this purpose and achievable performances are computed under realistic conditions. Numerical simulations carried out with the best configuration show that an isolated 7.7keV X-ray pulse with a peak power of 1.7TW and pulse length of 70as can be generated. In this particular example, the contrast is improved by two orders of magnitude and the peak power is enhanced by a factor of three, when compared with the previous scheme.1152Ysciescopu

    Family Planning Decisions, Perceptions and Gender Dynamics among Couples in Mwanza, Tanzania: A Qualitative Study.

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    Contraceptive use is low in developing countries which are still largely driven by male dominated culture and patriarchal values. This study explored family planning (FP) decisions, perceptions and gender dynamics among couples in Mwanza region of Tanzania. Twelve focus group discussions and six in-depth interviews were used to collect information from married or cohabiting males and females aged 18-49. The participants were purposively selected. Qualitative methods were used to explore family planning decisions, perceptions and gender dynamics among couples. A guide with questions related to family planning perceptions, decisions and gender dynamics was used. The discussions and interviews were tape-recorded, transcribed verbatim and analyzed manually and subjected to content analysis. Four themes emerged during the study. First, "risks and costs" which refer to the side effects of FP methods and the treatment of side -effects as well as the costs inherit in being labeled as an unfaithful spouse. Second, "male involvement" as men showed little interest in participating in family planning issues. However, the same men were mentioned as key decision-makers even on the number of children a couple should have and the child spacing of these children. Third, "gender relations and communication" as participants indicated that few women participated in decision-making on family planning and the number of children to have. Fourth, "urban-rural differences", life in rural favoring having more children than urban areas therefore, the value of children depended on the place of residence. Family Planning programs should adapt the promotion of communication as well as joint decision-making on FP among couples as a strategy aimed at enhancing FP use

    Descriptive epidemiology of cholera outbreak in Nigeria, January-November, 2018: implications for the global roadmap strategy

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    Background: The cholera outbreak in 2018 in Nigeria reaffirms its public health threat to the country. Evidence on the current epidemiology of cholera required for the design and implementation of appropriate interventions towards attaining the global roadmap strategic goals for cholera elimination however seems lacking. Thus, this study aimed at addressing this gap by describing the epidemiology of the 2018 cholera outbreak in Nigeria. Methods: This was a retrospective analysis of surveillance data collected between January 1st and November 19th, 2018. A cholera case was defined as an individual aged 2 years or older presenting with acute watery diarrhoea and severe dehydration or dying from acute watery diarrhoea. Descriptive analyses were performed and presented with respect to person, time and place using appropriate statistics. Results: There were 43,996 cholera cases and 836 cholera deaths across 20 states in Nigeria during the outbreak period, with an attack rate (AR) of 127.43/100,000 population and a case fatality rate (CFR) of 1.90%. Individuals aged 15 years or older (47.76%) were the most affected age group, but the proportion of affected males and females was about the same (49.00 and 51.00% respectively). The outbreak was characterised by four distinct epidemic waves, with higher number of deaths recorded in the third and fourth waves. States from the north-west and north-east regions of the country recorded the highest ARs while those from the north-central recorded the highest CFRs. Conclusion: The severity and wide-geographical distribution of cholera cases and deaths during the 2018 outbreak are indicative of an elevated burden, which was more notable in the northern region of the country. Overall, the findings reaffirm the strategic role of a multi-sectoral approach in the design and implementation of public health interventions aimed at preventing and controlling cholera in Nigeri

    A systematic review of the evidence for single stage and two stage revision of infected knee replacement

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    BACKGROUND: Periprosthetic infection about the knee is a devastating complication that may affect between 1% and 5% of knee replacement. With over 79 000 knee replacements being implanted each year in the UK, periprosthetic infection (PJI) is set to become an important burden of disease and cost to the healthcare economy. One of the important controversies in treatment of PJI is whether a single stage revision operation is superior to a two-stage procedure. This study sought to systematically evaluate the published evidence to determine which technique had lowest reinfection rates. METHODS: A systematic review of the literature was undertaken using the MEDLINE and EMBASE databases with the aim to identify existing studies that present the outcomes of each surgical technique. Reinfection rate was the primary outcome measure. Studies of specific subsets of patients such as resistant organisms were excluded. RESULTS: 63 studies were identified that met the inclusion criteria. The majority of which (58) were reports of two-stage revision. Reinfection rated varied between 0% and 41% in two-stage studies, and 0% and 11% in single stage studies. No clinical trials were identified and the majority of studies were observational studies. CONCLUSIONS: Evidence for both one-stage and two-stage revision is largely of low quality. The evidence basis for two-stage revision is significantly larger, and further work into direct comparison between the two techniques should be undertaken as a priority

    How do you say β€˜hello’? Personality impressions from brief novel voices

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    On hearing a novel voice, listeners readily form personality impressions of that speaker. Accurate or not, these impressions are known to affect subsequent interactions; yet the underlying psychological and acoustical bases remain poorly understood. Furthermore, hitherto studies have focussed on extended speech as opposed to analysing the instantaneous impressions we obtain from first experience. In this paper, through a mass online rating experiment, 320 participants rated 64 sub-second vocal utterances of the word β€˜hello’ on one of 10 personality traits. We show that: (1) personality judgements of brief utterances from unfamiliar speakers are consistent across listeners; (2) a two-dimensional β€˜social voice space’ with axes mapping Valence (Trust, Likeability) and Dominance, each driven by differing combinations of vocal acoustics, adequately summarises ratings in both male and female voices; and (3) a positive combination of Valence and Dominance results in increased perceived male vocal Attractiveness, whereas perceived female vocal Attractiveness is largely controlled by increasing Valence. Results are discussed in relation to the rapid evaluation of personality and, in turn, the intent of others, as being driven by survival mechanisms via approach or avoidance behaviours. These findings provide empirical bases for predicting personality impressions from acoustical analyses of short utterances and for generating desired personality impressions in artificial voices
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