634 research outputs found

    Open University Learning Analytics dataset

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    Learning Analytics focuses on the collection and analysis of learners’ data to improve their learning experience by providing informed guidance and to optimise learning materials. To support the research in this area we have developed a dataset, containing data from courses presented at the Open University (OU). What makes the dataset unique is the fact that it contains demographic data together with aggregated clickstream data of students’ interactions in the Virtual Learning Environment (VLE). This enables the analysis of student behaviour, represented by their actions. The dataset contains the information about 22 courses, 32,593 students, their assessment results, and logs of their interactions with the VLE represented by daily summaries of student clicks (10,655,280 entries). The dataset is freely available at https://analyse.kmi.open.ac.uk/open_dataset under a CC-BY 4.0 license

    On the Goodness-of-Fit Tests for Some Continuous Time Processes

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    We present a review of several results concerning the construction of the Cramer-von Mises and Kolmogorov-Smirnov type goodness-of-fit tests for continuous time processes. As the models we take a stochastic differential equation with small noise, ergodic diffusion process, Poisson process and self-exciting point processes. For every model we propose the tests which provide the asymptotic size α\alpha and discuss the behaviour of the power function under local alternatives. The results of numerical simulations of the tests are presented.Comment: 22 pages, 2 figure

    Perceived institutional support and small venture performance: The mediating role of entrepreneurial persistence

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    YesThis article examines the entrepreneurial persistence of opportunity-motivated entrepreneurs in Ghana. Specifically, it develops a theoretical model focusing on the relationships among perceived institutional support, entrepreneurial persistence and small venture performance, including how entrepreneurial networks condition the relationship between institutional support and entrepreneurial persistence. Using time-lagged data from 373 opportunity-motivated entrepreneurs leading small ventures in Ghana, we find broad support for our hypotheses. The insights from our study provide an integrative understanding of the relationships among perceived institutional support, entrepreneurial persistence and venture performance in an adverse environment. Theoretical and practical implications are discussed

    Adherence of community caretakers of children to pre-packaged antimalarial medicines (HOMAPAK(®)) among internally displaced people in Gulu district, Uganda

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    BACKGROUND: In 2002, home-based management of fever (HBMF) was introduced in Uganda, to improve access to prompt, effective antimalarial treatment of all fevers in children under 5 years. Implementation is through community drug distributors (CDDs) who distribute pre-packaged chloroquine plus sulfadoxine-pyrimethamine (HOMAPAK(®)) free of charge to caretakers of febrile children. Adherence of caretakers to this regimen has not been studied. METHODS: A questionnaire-based survey combined with inspection of blister packaging was conducted to investigate caretakers' adherence to HOMAPAK(®). The population surveyed consisted of internally displaced people (IDPs) from eight camps. RESULTS: A total of 241 caretakers were interviewed. 95.0% (CI: 93.3% – 98.4%) of their children had received the correct dose for their age and 52.3% of caretakers had retained the blister pack. Assuming correct self-reporting, the overall adherence was 96.3% (CI: 93.9% – 98.7%). The nine caretakers who had not adhered had done so because the child had improved, had vomited, did not like the taste of the tablets, or because they forgot to administer the treatment. For 85.5% of cases treatment had been sought within 24 hours. Blister packaging was considered useful by virtually all respondents, mainly because it kept the drugs clean and dry. Information provided on, and inside, the package was of limited use, because most respondents were illiterate. However, CDDs had often told caretakers how to administer the treatment. For 39.4% of respondents consultation with the CDD was their reported first action when their child has fever and 52.7% stated that they consult her/him if the child does not get better. CONCLUSION: In IDP camps, the HBMF strategy forms an important component of medical care for young children. In case of febrile illness, most caretakers obtain prompt and adequate antimalarial treatment, and adhere to it. A large proportion of malaria episodes are thus likely to be treated before complications can arise. Implementation in the IDP camps now needs to focus on improving monitoring, supervision and general support to CDDs, as well as on targeting them and caretakers with educational messages. The national treatment policy for uncomplicated malaria has recently been changed to artemether-lumefantrine. Discussions on a suitable replacement combination for HBMF are well advanced, and have raised new questions about adherence

    The impact of childhood vaccines on bacterial carriage in the nasopharynx: a longitudinal study.

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    BACKGROUND: There is increasing evidence that childhood vaccines have effects that extend beyond their target disease. The objective of this study was to assess the effects of routine childhood vaccines on bacterial carriage in the nasopharynx. METHODS: A cohort of children from rural Gambia was recruited at birth and followed up for one year. Nasopharyngeal swabs were taken immediately after birth, every two weeks for the first six months and then every other month. The presence of bacteria in the nasopharynx (Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus) was compared before and after the administration of DTP-Hib-HepB and measles-yellow fever vaccines. RESULTS: A total of 1,779 nasopharyngeal swabs were collected from 136 children for whom vaccination data were available. The prevalence of bacterial carriage was high: 82.2% S. pneumoniae, 30.6%, S.aureus, 27.8% H. influenzae. Carriage of H. influenzae (OR = 0.36; 95% CI: 0.13, 0.99) and S. pneumoniae (OR = 0.25; 95% CI: 0.07, 0.90) were significantly reduced after measles-yellow fever vaccination; while DTP-Hib-HepB had no effect on bacterial carriage. CONCLUSIONS: Nasopharyngeal bacterial carriage is unaffected by DTP-Hib-HepB vaccination and reduced after measles-yellow fever vaccination

    The Effect of Pose on the distribution of Edge Gradients in Omnidirectional Images

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    Images from omnidirectional cameras are used frequently in applications involving artificial intelligence and robotics as a source of rich information about the surroundings. A useful feature that can be extracted from these images is the distribution of gradients of the edges in the scene. This distribution is affected by the pose of the camera on-board a robot at any given location in the environment. This paper investigates the effect of the pose on this distribution. The gradients in the images are extracted and arranged into a histogram which is then compared to the histograms of other images using a chi-squared test. It is found that any differences in the distribution are not specific to either the position or orientation and that there is a significant difference in the distributions of two separate locations. This can aid in the localisation of robots when navigating

    Randomized Trial of Artesunate+Amodiaquine, Sulfadoxine-Pyrimethamine+Amodiaquine, Chlorproguanal-Dapsone and SP for Malaria in Pregnancy in Tanzania

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    Malaria in pregnancy is serious, and drug resistance in Africa is spreading. Drugs have greater risks in pregnancy and determining the safety and efficacy of drugs in pregnancy is therefore a priority. This study set out to determine the efficacy and safety of several antimalarial drugs and combinations in pregnant women with uncomplicated malaria.Pregnant women with non-severe, slide proven, falciparum malaria were randomised to one of 4 regimes: sulfadoxine-pyrimethamine [SP]; chlorproguanil-dapsone [CD]; SP+amodiaquine [SP+AQ] or amodiaquine+artesunate [AQ+AS]. Randomisation was on a 1ratio2ratio2ratio2 ratio. Women were admitted for treatment, and followed at days 7, 14, 21, 28 after the start of treatment, at delivery and 6 weeks after delivery to determine adverse events, clinical and parasitological outcomes. Primary outcome was parasitological failure by day 28.1433 pregnant women were screened, of whom 272 met entry criteria and were randomised; 28 to SP, 81 to CD, 80 to SP+AQ and 83 to AQ+AS. Follow-up to day 28 post treatment was 251/272 (92%), and to 6 weeks following delivery 91%. By day 28 parasitological failure rates were 4/26 (15%, 95%CI 4-35) in the SP, 18/77 (23%, 95%CI 14-34) in the CD, 1/73 (1% 95%CI 7-0.001) in the SP+AQ and 7/75 (9% 95%CI 4-18) in the AQ+AS arms respectively. After correction by molecular markers for reinfection the parasitological failure rates at day 28 were 18% for CD, 1% for SP+AQ and 4.5% for AQ+AS. There were two maternal deaths during the trial. There was no apparent excess of stillbirths or adverse birth outcomes in any arm. Parasitological responses were strikingly better in pregnant women than in children treated with the same drugs at this site.Failure rates with monotherapy were unacceptably high. The two combinations tested were efficacious and appeared safe. It should not be assumed that efficacy in pregnancy is the same as in children.ClinicalTrials.gov NCT00146731

    Knowledge and utilization of intermittent preventive treatment for malaria among pregnant women attending antenatal clinics in primary health care centers in rural southwest, Nigeria: a cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Intermittent preventive treatment for prevention of malaria in pregnancy (IPTp) is a key component of malaria control strategy in Nigeria and sulfadoxine-pyrimethamine (SP) is the drug of choice. Despite the evidence of the effectiveness of IPTp strategy using SP in reducing the adverse effects of malaria during pregnancy the uptake and coverage in Nigeria is low. This study set out to assess the use of IPTp among pregnant women attending primary health centres in the rural area and determine factors that influence the uptake.</p> <p>Methods</p> <p>A cross-sectional study was carried out between July and August 2007 among 209 pregnant women selected by systematic random sampling from antenatal care attendees at primary health care in a rural Local Government Area of Ekiti State, Nigeria. Information on knowledge of IPT, delivery, adherence and acceptability was obtained using an interviewer administered questionnaire. Descriptive statistics such as means, range, proportions were used. Chi-square test was used to examine association between categorical variables. All analyses were performed at 5% level of significance.</p> <p>Results</p> <p>One hundred and nine of 209 (52.2%) respondents have heard about IPTp but only 26 (23.9%) were able to define it. Fifty seven (27.3%) reported to have received at least one dose of IPTp during the index pregnancy and all were among those who have heard of IPTp (52.3%). Twenty one of the 57 (36.8%) took the SP in the clinic. Only three of the twenty-one (14.3%) were supervised by a health worker. Twenty two of the 36 women (61.1%) who did not take their drugs in the clinic would have liked to do so if allowed to bring their own drinking cups. Almost half (43.9%) of those who had used IPTp during the index pregnancy expressed concern about possible adverse effect of SP on their pregnancies. Periodic shortages of SP in the clinics were also reported.</p> <p>Conclusion</p> <p>In this study, IPTp use among pregnant women was very low and there was poor adherence to the Directly Observed Therapy (DOT) scheme. Concerted effort should be made to increase awareness of IPTp among the public especially women of child bearing age. Health workers should also be trained and monitored to ensure adherence.</p

    Fisher Information as a Metric of Locally Optimal Processing and Stochastic Resonance

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    The origins of Fisher information are in its use as a performance measure for parametric estimation. We augment this and show that the Fisher information can characterize the performance in several other significant signal processing operations. For processing of a weak signal in additive white noise, we demonstrate that the Fisher information determines (i) the maximum output signal-to-noise ratio for a periodic signal; (ii) the optimum asymptotic efficacy for signal detection; (iii) the best cross-correlation coefficient for signal transmission; and (iv) the minimum mean square error of an unbiased estimator. This unifying picture, via inequalities on the Fisher information, is used to establish conditions where improvement by noise through stochastic resonance is feasible or not
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