1,721,279 research outputs found
A study of the incubation period, or age at onset, of the transmissible spongiform encephalopathies/prion diseases.
Full text linkIn order to model epidemics of infectious diseases, particularly to estimate probable numbers of cases with onset at any particular time, it is necessaiy to incorporate a term for the incubation period frequency distribution. Sartwell's hypothesis states that the incubation period frequency distribution for infectious disease is generally a log-normal distribution, based on his examination of disease with short incubation periods. However, it may not apply to diseases with long incubation periods. During the course of an epidemic of a disease with a long incubation period, left and right censoring makes direct observation of the frequency distribution highly unreliable; in addition, time of infection is often unknown. Therefore, for a previously undescribed disease, methods other than direct observation must be employed. One method is to extrapolate from information available for other diseases.
In evaluation of Sartwell's hypothesis as applied to diseases with long incubation periods, examination of transfijsion-associated AIDS data was inconclusive. Examination of data for experimental transmissible spongiform encephalopathy (TSE)/prion disease in several species suggests that it may not apply. For natural TSE/prion disease, age at onset is used generally as a 'proxy' for incubation period since infection time is rarely known; the validity of this may vary with the disease type and species being examined. Using this measure, again Sartwell's hypothesis was not confirmed.
For both incubation period and age at onset, evidence presented suggests that observed frequency distribution coefficient of skewness is associated with modal age at onset (and thus indirectly with prior age at infection, where appropriate), an earlier modal age at onset resulting in a larger observed coefficient of skewness. The relationship of this association with Sartwell's findings is discussed; they are not incompatible. In addition, an association between observed coefficient of skewness and sample size is demonstrated and the implications discussed
The effect of health education on women's treatment-seeking behaviour: Findings from a cluster randomised trial and an in-depth investigation of hysterectomy in Gujarat, India
Full text linkA community-based health insurance scheme operated by the Self-Employed Women’s Association
(SEWA), an organisation of women workers in India, reported that the leading reasons for inpatient
hospitalisation claims by adult women were diarrhoea, fever and hysterectomy – the latter at the
average age of 37. In 2010, SEWA initiated a cluster randomised trial to evaluate whether community
health worker-led education amongst insured and uninsured adult women could reduce morbidity,
hospitalisation and insurance claims related to these three conditions.
This thesis reports the findings of the intervention evaluation and of an in-depth examination of
hysterectomy, the most common cause of hospitalisation. Literature reviews were conducted on the
effect of community health worker-led group health education and on the frequency of hysterectomy in
low and middle-income countries. Analysis of the cluster randomised trial utilised data from SEWA’s
insurance database and four household surveys. Hysterectomy was explored through an in-depth
qualitative study and quantitative analyses using the study cohort to estimate incidence and identify
determinants of the procedure. Lastly, findings were synthesised with process data to examine the
intervention process, with a focus on hysterectomy.
Statistical analyses indicated no evidence of an intervention effect on insurance claims, hospitalisations
or morbidity related to fever, diarrhoea and hysterectomy. There was no evidence of effect
modification by insurance status. Hysterectomy amongst women in their mid-thirties appeared to be
rooted in its normalisation as a prophylactic, permanent treatment for gynaecological ailments.
Incidence of hysterectomy was associated with income, age and number of children. Evaluation of the
intervention process suggested that improved knowledge was necessary, but not sufficient, to change
women’s treatment-seeking behaviour regarding hysterectomy. Interventions to reduce hysterectomy
must integrate approaches that address the structural determinants of the procedure, such as the lack
of reproductive and sexual health services, providers’ behaviour towards low-income women and
attitudes towards the utility of the uterus
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
PRIME-IPD SERIES Part 3. The PRIME-IPD tool fills a gap in guidance for preparing IPD for analysis
No full textThis is the accepted manuscript version of the work published in its final form as Dewidar, Omar; Riddle, Alison; Ghogomu, Elizabeth; Hossain, Alomgir; Arora, Paul; Bhutta, Zulfiqar A; Black, Robert E; Cousens, Simon; Mathew, Christine; Trawin, Jessica; Tugwell, Peter; Welch, Vivian; Wells, George A. Plant Breeding; Volume: 136; Pages: 224-226; https://doi.org/10.1016/j.jclinepi.2021.05.001
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Control of Salmonella infection in pigs at the farm level in Great Britain
Full text linkSalmonella is an important zoonotic pathogen and 10,000 cases of human
salmonellosis are reported annually in the UK. The most commonly implicated
serovars are S. Enteritidis and S. Typhimurium. Since a quarter of British pigs
carry Salmonella in their gut at slaughter, there is an urgent requirement for
improved control strategies that could benefit human health. A literature review
showed that hygiene, biosecurity and feed exposures were important risk factors
for Salmonella infection in pigs, which originates from environmental
contamination or introducing infected pigs into the herd. The aim of this research
was to design and test an intervention to control Salmonella in pigs. The following
objectives were achieved:
1. An evaluation of tests for Salmonella in pigs: isolation by culture and the
meat juice (MJ) ELISA, to inform test selection for the intervention study.
2. A national farm-level survey to estimate the variation in Salmonella
prevalence between farms and to investigate risk factors associated with
infection.
3. An analysis of a merged MJ ELISA dataset with a quality assurance
dataset to provide additional information on risk factors.
4. A randomised controlled trial of an enhanced hygiene and biosecurity
protocol intended to control Salmonella infection in finisher pigs.
The intervention was tested on 48 farms. The primary outcome was the pen
incidence rate of Salmonella infection, measured by culture of pooled pen floor
faecal samples. No important change in incidence between intervention and
comparison groups was seen. Analysis by reported behaviour showed that
improved attention to between-batch cleaning and disinfection was beneficial.
The prevalence of infected pens shortly after re-stocking had an overwhelming
effect on incidence whilst improved hygiene during production had relatively little
effect. Therefore, enhanced hygiene and biosecurity may yield benefits in
Salmonella control, but these may be overwhelmed by the introduction of
infection at re-stocking or through residual environmental contamination
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
The influences of distance on health facility delivery in rural Zambia
Full text linkSkilled attendance at delivery is crucial for decreasing maternal and neonatal
mortality. My literature review showed that epidemiological research on factors
influencing whether women receive skilled attendance has so far been
hampered by a lack of data on health service availability, and is often restricted
to investigating household and individual factors. Distance to health services,
however, is likely to play an important role.
The availability of geographic coordinates in both national household survey,
population census and health facility census in Zambia provides the opportunity
to combine user and provider information on a large scale. These datasets were
linked to investigate the influence that distance has on place of delivery, while
adjusting for other influential factors such as education, wealth and autonomy in
a multilevel model.
Classifying Zambian health facilities according to their level of delivery care
showed that 88% of facilities are not staffed or equipped to provide even Basic
Emergency Obstetric Care (EmOC) and therefore cannot save a mother's life in
case of complications. Around half of the Zambian population lives further than
15km from a Basic EmOC facility; less than 10% in urban areas and over 70%
in rural areas.
Using data from over 3000 rural births, I demonstrate that the odds of delivering
in a facility are 4 times higher within 1km of a facility as compared to 20km, and
additionally 2.5 times higher if that facility offers Comprehensive EmOC rather
than substandard care. If all mothers lived within 5km of Basic EmOC, 16% of
home deliveries could be avoided, a population attributable fraction of similar
magnitude as for education or wealth.
Lack of geographical access to EmOC is a key factor explaining why most rural
deliveries in Zambia still occur at home without skilled care; this needs to be
addressed to lower maternal and neonatal mortality
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