1,721,128 research outputs found
Correction to: Spatial prediction of malaria prevalence in Papua New Guinea: a comparison of Bayesian decision network and multivariate regression modelling approaches for improved accuracy in prevalence prediction
Full text linkBACKGROUND: Considerable progress towards controlling malaria has been made in Papua New Guinea through the national malaria control programme's free distribution of long-lasting insecticidal nets, improved diagnosis with rapid diagnostic tests and improved access to artemisinin combination therapy. Predictive prevalence maps can help to inform targeted interventions and monitor changes in malaria epidemiology over time as control efforts continue. This study aims to compare the predictive performance of prevalence maps generated using Bayesian decision network (BDN) models and multilevel logistic regression models (a type of generalized linear model, GLM) in terms of malaria spatial risk prediction accuracy. METHODS: Multilevel logistic regression models and BDN models were developed using 2010/2011 malaria prevalence survey data collected from 77 randomly selected villages to determine associations of Plasmodium falciparum and Plasmodium vivax prevalence with precipitation, temperature, elevation, slope (terrain aspect), enhanced vegetation index and distance to the coast. Predictive performance of multilevel logistic regression and BDN models were compared by cross-validation methods. RESULTS: Prevalence of P. falciparum, based on results obtained from GLMs was significantly associated with precipitation during the 3 driest months of the year, June to August (β = 0.015; 95% CI = 0.01-0.03), whereas P. vivax infection was associated with elevation (β = - 0.26; 95% CI = - 0.38 to - 3.04), precipitation during the 3 driest months of the year (β = 0.01; 95% CI = - 0.01-0.02) and slope (β = 0.12; 95% CI = 0.05-0.19). Compared with GLM model performance, BDNs showed improved accuracy in prediction of the prevalence of P. falciparum (AUC = 0.49 versus 0.75, respectively) and P. vivax (AUC = 0.56 versus 0.74, respectively) on cross-validation. CONCLUSIONS: BDNs provide a more flexible modelling framework than GLMs and may have a better predictive performance when developing malaria prevalence maps due to the multiple interacting factors that drive malaria prevalence in different geographical areas. When developing malaria prevalence maps, BDNs may be particularly useful in predicting prevalence where spatial variation in climate and environmental drivers of malaria transmission exists, as is the case in Papua New Guinea
Spatiotemporal and demographic characteristics of scrub typhus in Southwest China, 2006-2017: an analysis of population-based surveillance data
No full textScrub typhus is a life-threatening vector-borne disease. During the past decade, the number of areas affected by this disease has expanded in many countries. In this study, we aim to identify the spatiotemporal and demographic characteristics of scrub typhus in Southwest China, an emerging endemic region for scrub typhus. Population-based surveillance data capturing scrub typhus cases in two provinces of Southwest China during 2006-2017 were retrieved. Descriptive temporal and spatial analyses were conducted and stratified by age group. The space-time scan statistic was used to identify spatiotemporal clusters of scrub typhus occurrence at the county level. During the study period, 30,001 scrub typhus cases were recorded in Southwest China, with a total of 61.0% (191/313) of counties being affected; most cases (94.3%) occurred in rural areas. The annual incidence rate increased substantially from 0.25/100,000 in 2006 to 5.38/100,000 in 2017 (> 21-fold change). The 0-4-year-old and 45-64-year-old subgroups had the highest cumulative incidence rates (57.46 and 32.98/100,000, respectively). Furthermore, since 2006, the 0-4-year-old (slope=0.83, p<0.01) and 45-64-year-old (slope=0.69, p<0.01) age groups have had the highest increases in incidence of all age groups. The most likely spatial cluster of overall cases (relative risk=4.13, p<0.01) occurred in the southern region of Southwest China and included 41 high-risk counties. In conclusion, scrub typhus appears to be widely distributed and rapidly increasing in Southwest China. Young children and middle-aged adults were the most severely affected groups, and the disease appeared to predominantly cluster in the southern part of Southwest China. Further in-depth surveys to determine the epidemiological characteristics and driving factors of this emerging disease and to facilitate effective control programmes among high-risk groups in the affected areas should be promoted.</p
Risk mapping of scrub typhus infections in Qingdao city, China
No full textBACKGROUND: The emergence and re-emergence of scrub typhus has been reported in the past decade in many global regions. In this study, we aim to identify potential scrub typhus infection risk zones with high spatial resolution in Qingdao city, in which scrub typhus is endemic, to guide local prevention and control strategies.METHODOLOGY/PRINCIPAL FINDINGS: Scrub typhus cases in Qingdao city during 2006-2018 were retrieved from the Chinese National Infectious Diseases Reporting System. We divided Qingdao city into 1,101 gridded squares and classified them into two categories: areas with and without recorded scrub typhus cases. A boosted regression tree model was used to explore environmental and socioeconomic covariates associated with scrub typhus occurrence and predict the risk of scrub typhus infection across the whole area of Qingdao city. A total of 989 scrub typhus cases were reported in Qingdao from 2006-2018, with most cases located in rural and suburban areas. The predicted risk map generated by the boosted regression tree models indicated that the highest infection risk areas were mainly concentrated in the mid-east and northeast regions of Qingdao, with gross domestic product (20.9%±1.8% standard error) and annual cumulative precipitation (20.3%±1.1%) contributing the most to the variation in the models. By using a threshold environmental suitability value of 0.26, we identified 757 squares (68.7% of the total) with a favourable environment for scrub typhus infection; 66.2% (501/757) of the squares had not yet recorded cases. It is estimated that 6.32 million people (72.5% of the total population) reside in areas with a high risk of scrub typhus infection.CONCLUSIONS/SIGNIFICANCE: Many locations in Qingdao city with no recorded scrub typhus cases were identified as being at risk for scrub typhus occurrence. In these at-risk areas, awareness and capacity for case diagnosis and treatment should be enhanced in the local medical service institutes.</p
A Clinical, Pathological and Demographic Study of an Unusual Locomotor Disorder of Sheep
Full text linkKangaroo Gait is a locomotor disorder of sheep, which was first described in New Zealand in 1978, and was subsequently reported in the United Kingdom, initially in 1986. The reported features of the condition included acute onset bilateral forelimb paresis in adult female sheep occurring during lactation or late gestation, Wallerian degeneration of the radial nerves, subsequent regeneration, and, in most cases, clinical recovery. The aetiology of Kangaroo Gait remained obscure and there was little information regarding the incidence, the geographical distribution or the economic importance of this condition. This study was undertaken with the aims of characterising Kangaroo Gait in northern Britain in terms of its clinical, pathological and demographic features. Thirteen adult female sheep from six flocks in south west Scotland, which had presented with an abnormal forelimb gait, were subjected to a clinical investigation, and four of these adult female sheep, as well as two lambs from one adult female, were submitted for pathological examination. The anamnesis for each flock did not reveal consistent problems with general management, nutrition, disease occurrence, or the presence of toxic plants or chemicals. Apart from the abnormal locomotion, physical examinations and ancillary investigations did not detect any consistent abnormalities. Neurological examinations resulted consistently in findings of bilateral forelimb paresis and reduced muscle bulk of the proximal forelimbs. Variable findings included proprioceptive deficits in the forelimbs and normal pedal withdrawal reflexes in all four limbs. A clinical diagnosis of Kangaroo Gait was determined for the 13 sheep. Evidence of Wallerian degeneration was found in the radial nerves of one adult female (onset of clinical signs during lactation), and minor changes were found in the radial nerves of a second (onset of clinical signs during gestation) but no significant abnormalities were detected in the peripheral nerves of the remaining adult females or the lambs. Non-specific changes were detected in the spinal cord of two adult females and the brain of one adult female (onset of clinical signs during gestation). Results suggested that Kangaroo Gait could occur in adult female sheep of a number of breeds, between the ages of one and seven years, onset of clinical signs could occur during late gestation or early to mid lactation, and recovery from clinical signs was not dependent on cessation of lactation. It was suggested that a range of pathological changes were associated with this condition, and that close observation of animals around the time of onset of clinical signs, and recruitment of individuals for detailed pathological examinations at that time, would be essential for determining the aetiopathogenesis of Kangaroo Gait. In order to gain more information, two questionnaire studies were undertaken. The first survey was mailed to veterinary surgeons in all practices in Northern Britain which, according to the Directory of Veterinary Practices (Hall, 1997), provided veterinary care for sheep, and the second was mailed to sheep flock owners and managers located in the Scottish Borders, who were recruited via veterinary surgeons. Response rates of 84.7% and 30.7% were achieved. In total, 29.7% and 24.1% of respondents had identified one or more cases of Kangaroo Gait in their practice area or flocks at some time. Almost all respondents who had identified cases indicated that adult females were affected, most often during lactation, and less commonly during late gestation. Results suggested that Kangaroo Gait was more common among commercial cross breeds, and was less common on hill farms than upland or lowland farms. The annual number of affected individuals and flocks had increased since the condition was first identified. Comparing the results of the two surveys revealed that a majority of cases of Kangaroo Gait and other locomotor disorders were not reported to veterinary surgeons. Further epidemiological investigations could prove useful in determining risk factors for the occurrence of Kangaroo Gait. However, it was suggested that economic crises in the UK sheep industry, accompanied by a perception that Kangaroo Gait is of little economic importance, make it unlikely that detailed studies of this condition will be conducted in the foreseeable future
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Reviewing dengue : still a neglected tropical disease?
No full textDengue is currently listed as a "neglected tropical disease" (NTD). But is dengue still an NTD or not? Classifying dengue as an NTD may carry advantages, but is it justified? This review considers the criteria for the definition of an NTD, the current diverse lists of NTDs by different stakeholders, and the commonalities and differences of dengue with other NTDs. We also review the current research gaps and research activities and the adequacy of funding for dengue research and development (R&D) (2003-2013). NTD definitions have been developed to a higher precision since the early 2000s, with the following main features: NTDs are characterised as a) poverty related, b) endemic to the tropics and subtropics, c) lacking public health attention, d) having poor research funding and shortcomings in R&D, e) usually associated with high morbidity but low mortality, and f) often having no specific treatment available. Dengue meets most of these criteria, but not all. Although dengue predominantly affects resource-limited countries, it does not necessarily only target the poor and marginalised in those countries. Dengue increasingly attracts public health attention, and in some affected countries it is now a high profile disease. Research funding for dengue has increased exponentially in the past two decades, in particular in the area of dengue vaccine development. However, despite advances in dengue research, dengue epidemics are increasing in frequency and magnitude, and dengue is expanding to new areas. Specific treatment and a highly effective vaccine remain elusive. Major research gaps exist in the area of integrated surveillance and vector control. Hence, although dengue differs from many of the NTDs, it still meets important criteria commonly used for NTDs. The current need for increased R& D spending, shared by dengue and other NTDs, is perhaps the key reason why dengue should continue to be considered an NTD
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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