308 research outputs found
Negotiating the Maze: Case based, Collaborative Distance Learning in Dentistry
The module was developed as an elective to give motivated senior dental students an opportunity to expand their horizons in planning oral rehabilitation. It comprised one tutor and 12 students, from five universities world-wide, communicating on the World Wide Web (WWW), to develop oral rehabilitation plans for simulated patients. Trigger material came from one of two Case Profiles and consisted of diagnostic casts and details of the clinical and radiographic examination in WWW/CD-ROM form. No background material was supplied as to the "patient's" age, sex, history or main concern(s). Students worked in groups of three, each student from a different location. Individual students were given a role within the group: "Patient", who developed a "personal background" belonging to the trigger examination material, "Academic" who identified state-of-the-art treatment options available for the dental treatment needs identified by the group and "General Practitioner" who tailored these options to the "patient's" needs and wants. Student feedback focused on their perception of their experience with the program in response to a questionnaire comprising 11 structured and four "open" questions. All students felt that the program increased their confidence in planning oral rehabilitation. Ten students felt that the "best thing about the program" was the interaction with students from other universities and the exposure to different philosophies from the different schools. Eight students mentioned their increased awareness of the importance of patient input into holistic planning. Under the heading "What was the worst thing", students cited some technical hitches and the snowball effect of two sluggish students who were not identified early enough and thus impacted negatively on the working of their groups. Student feedback showed that the module succeeded in its aims but needed modification to improve the logistics of working with an extended campu
Reap the crop wild relatives for breeding future crops
Crop wild relatives (CWRs) have provided breeders with several 'game-changing' traits or genes that have boosted crop resilience and global agricultural production. Advances in breeding and genomics have accelerated the identification of valuable CWRs for use in crop improvement. The enhanced genetic diversity of breeding pools carrying optimum combinations of favorable alleles for targeted crop-growing regions is crucial to sustain genetic gain. In parallel, growing sequence information on wild genomes in combination with precise gene-editing tools provide a fast-track route to transform CWRs into ideal future crops. Data-informed germplasm collection and management strategies together with adequate policy support will be equally important to improve access to CWRs and their sustainable use to meet food and nutrition security targets
Planetary bearing defect detection in a commercial helicopter main gearbox with vibration and acoustic emission
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Helicopter gearboxes significantly differ from other transmission types and exhibit unique behaviors that reduce the effectiveness of traditional fault diagnostics methods. In addition, due to lack of redundancy, helicopter transmission failure can lead to catastrophic accidents. Bearing faults in helicopter gearboxes are difficult to discriminate due to the low signal to noise ratio (SNR) in the presence of gear vibration. In addition, the vibration response from the planet gear bearings must be transmitted via a time-varying path through the ring gear to externally mounted accelerometers, which cause yet further bearing vibration signal suppression. This research programme has resulted in the successful proof of concept of a broadband wireless transmission sensor that incorporates power scavenging whilst operating within a helicopter gearbox. In addition, this paper investigates the application of signal separation techniques in detection of bearing faults within the epicyclic module of a large helicopter (CS-29) main gearbox using vibration and Acoustic Emissions (AE). It compares their effectiveness for various operating conditions. Three signal processing techniques including an adaptive filter, spectral kurtosis and envelope analysis, were combined for this investigation. In addition, this research discusses the feasibility of using AE for helicopter gearbox monitoring
Bearing signal separation enhancement with application to helicopter transmission system
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Bearing vibration signal separation is essential for fault detection of gearboxes, especially where the vibration is nonstationary, susceptible to background noise, and subjected to an arduous transmission path from the source to the receiver. This paper presents a methodology for improving fault detection via a series of vibration signal processing techniques, including signal separation, synchronous averaging (SA), spectral kurtosis (SK), and envelope analysis. These techniques have been tested on experimentally obtained vibration data acquired from the transmission system of a CS-29 Category A helicopter gearbox operating under different bearing damage conditions. Results showed successful enhancement of bearing fault detection on the second planetary stage of the gearbo
Patient characteristics associated with COVID-19 positivity and fatality in Nigeria: retrospective cohort study
Objective: Despite the increasing disease burden, there is
a dearth of context-specific evidence on the risk factors for
COVID-19 positivity and subsequent death in Nigeria. Thus,
the study objective was to identify context-specific factors
associated with testing positive for COVID-19 and fatality
in Nigeria.
Design Retrospective cohort study.
Setting: COVID-19 surveillance and laboratory centres in
36 states and the Federal Capital Territory reporting data to
the Nigeria Centre for Disease Control.
Participants: Individuals who were investigated for SARSCoV-2 using real-time PCR testing during the study period
27 February–8 June 2020.
Methods: COVID-19 positivity and subsequent mortality.
Multivariable logistic regression analyses were performed
to identify factors independently associated with both
outcome variables, and findings are presented as adjusted
ORs (aORs) and 95% CIs.
Results: A total of 36 496 patients were tested for
COVID-19, with 10 517 confirmed cases. Of 3215
confirmed cases with available clinical outcomes, 295
died. Factors independently associated with COVID-19
positivity were older age (p value for trend<0.0001), male
sex (aOR 1.11, 95%CI 1.04 to 1.18) and the following
presenting symptoms: cough (aOR 1.23, 95% CI 1.13 to
1.32), fever (aOR 1.45, 95% CI 1.45 to 1.71), loss of smell
(aOR 7.78, 95% CI 5.19 to 11.66) and loss of taste (aOR
2.50, 95% CI 1.60 to 3.90). An increased risk of mortality
following COVID-19 was observed in those aged ≥51
years, patients in farming occupation (aOR 7.56, 95% CI
1.70 to 33.53) and those presenting with cough (aOR 2.06,
95% CI 1.41 to 3.01), breathing difficulties (aOR 5.68, 95%
CI 3.77 to 8.58) and vomiting (aOR 2.54, 95% CI 1.33 to
4.84).
Conclusion: The significant risk factors associated with
COVID-19 positivity and subsequent mortality in the
Nigerian population are similar to those reported in studies
from other countries and should guide clinical decisions for
COVID-19 testing and specialist care referrals
Are physical symptoms among survivors of a disaster presented to the general practitioner? A comparison between self-reports and GP data
<p>Abstract</p> <p>Background</p> <p>Most studies examining medically unexplained symptoms (MUS) have been performed in primary or secondary care and have examined symptoms for which patients sought medical attention. Disasters are often described as precipitating factors for MUS. However, health consequences of disasters are typically measured by means of questionnaires, and it is not known whether these self-reported physical symptoms are presented to the GP. It is also not known if the self-reported symptoms are related to a medical disorder or if they remain medically unexplained. In the present study, three research questions were addressed. Firstly, were self-reported symptoms among survivors presented to the GP? Secondly, were the symptoms presented to the GP associated with a high level of functional impairment and distress? Thirdly, what was the GP's clinical judgment of the presented symptoms, i.e. were the symptoms related to a medical diagnosis or could they be labeled MUS?</p> <p>Methods</p> <p>Survivors of a man-made disaster (N = 887) completed a questionnaire 3 weeks (T1) and 18 months (T2) post-disaster. This longitudinal health survey was combined with an ongoing surveillance program of health problems registered by GPs.</p> <p>Results</p> <p>The majority of self-reported symptoms was not presented to the GP and survivors were most likely to present persistent symptoms to the GP. For example, survivors with stomachache at both T1 and T2 were more likely to report stomachache to their GP (28%) than survivors with stomachache at only T1 (6%) or only T2 (13%). Presentation of individual symptoms to the GP was not consistently associated with functional impairment and distress. 56 – 91% of symptoms were labeled as MUS after clinical examination.</p> <p>Conclusion</p> <p>These results indicate that the majority of self-reported symptoms among survivors of a disaster are not presented to the GP and that the decision to consult with a GP for an individual symptom is not dependent on the level of impairment and distress. Also, self-reported physical symptoms such as headache, back pain and shortness of breath are likely to remain medically unexplained after the clinical judgment of a GP.</p
Qualitative study on the socio-cultural determinants of care of children orphaned by AIDS in the Ashanti and Eastern regions of Ghana
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