472 research outputs found
Southern Ocean bottom water characteristics in CMIP5 models
Southern Ocean deep water properties and formation processes in climate models are indicative of their capability to simulate future climate, heat and carbon uptake, and sea level rise. Southern Ocean temperature and density averaged over 1986–2005 from 15 CMIP5 (Coupled Model Intercomparison Project Phase 5) climate models are compared with an observed climatology, focusing on bottom water. Bottom properties are reasonably accurate for half the models. Ten models create dense water on the Antarctic shelf, but it mixes with lighter water and is not exported as bottom water as in reality. Instead, most models create deep water by open ocean deep convection, a process occurring rarely in reality. Models with extensive deep convection are those with strong seasonality in sea ice. Optimum bottom properties occur in models with deep convection in the Weddell and Ross Gyres. Bottom Water formation processes are poorly represented in ocean models and are a key challenge for improving climate predictions
An ATM System Model and Wireless Channel Simulation
Congestion in the low frequency regions of the electromagnetic spectrum and demand for support of high bandwidth applications has prompted widespread investigations into networking technologies and communications media. Traditional networking technologies such as Ethernet that are not capable of adequately supporting high bandwidth applications (e.g. videoconferencing) are being replaced by high speed, high bandwidth technologies such as Asynchronous Transfer Mode (ATM). In the communications media market, wireless systems are becoming ubiquitous due to their ease of installation and maintenance costs. In this research, the networking technology of interest is ATM. ATM used a cell switching architecture that allows seamless support for all traffic types. It is also capable of providing guaranteed quality of service to different applications. This research seeks to develop a model of an ATM system in order to simulate the processes of file manipulation of an application in an ATM network in which a reliable transmissions medium is deployed. The transmission medium under investigation is a wireless optical communication link (laser). Laser systems offer a number of advantages over microwave systems. They do not require an operating license and they potentially offer larger bandwidth. Similar to microwave systems however, the performance of the laser link is dependent on atmospheric conditions. Scattering and absorption of the signal by atmospheric/weather particles may produce power losses in the transmitted signals. Theoretical models predicting such propagation impairments are widely available for microwave systems. However, there is little information available for optical systems. In this project, a model is developed to predict the effects due to rain on an optical link. This atmospheric channel model is base on the from of the drop size distribution proposed by [Marshall and Palmer, pp.165-166] and the results for the terminal velocity of raindrops found by [Gunn-and –Kinzer, pp.243-248] Experimental tests were conducted so that comparison could be made with both theoretical models developed
Changes in global ocean bottom properties and volume transports in CMIP5 models under climate change scenarios
Changes in bottom temperature, salinity and density in the global ocean by 2100 for CMIP5 climate models are investigated for the climate change scenarios RCP4.5 and RCP8.5. The mean of 24 models shows a decrease in density in all deep basins except the North Atlantic which becomes denser. The individual model responses to climate change forcing are more complex: regarding temperature, the 24 models predict a warming of the bottom layer of the global ocean; in salinity, there is less agreement regarding the sign of the change, especially in the Southern Ocean. The magnitude and equatorward extent of these changes also vary strongly among models. The changes in properties can be linked with changes in the mean transport of key water masses. The Atlantic Meridional Overturning Circulation weakens in most models and is directly linked to changes in bottom density in the North Atlantic. These changes are due to the intrusion of modified Antarctic Bottom Water, made possible by the decrease in North Atlantic Deep Water formation. In the Indian, Pacific and South Atlantic, changes in bottom density are congruent with the weakening in Antarctic Bottom Water transport through these basins. We argue that the greater the 1986-2005 meridional transports, the more changes have propagated equatorwards by 2100. However, strong decreases in density over 100 years of climate change cause a weakening of the transports. The speed at which these property changes reach the deep basins is critical for a correct assessment of the heat storage capacity of the oceans as well as for predictions of future sea level rise
Beliefs, barriers and preferences of European overweight women to adopt a healthier lifestyle in pregnancy to minimize risk of developing gestational diabetes mellitus: an explorative study
Introduction: Overweight and obese women are at high risk of developing gestational diabetes mellitus (GDM). Lifestyle programs might help curb the GDM risk. We explored beliefs, perceived barriers and preferences regarding lifestyle changes among overweight European pregnant women to help inform the development of future high quality lifestyle interventions.
Methods: An explorative mixed methods, two-staged study was conducted to gather information from pregnant European women (BMI≥25kg/m2). In three European countries (Belgium, Netherlands, United Kingdom) interviews were conducted, followed by questionnaires in six other European countries (Austria, Denmark, Ireland, Italy, Poland, Spain). Content analysis, descriptive and chi square statistics were applied (p<0.05).
Results: Women preferred to obtain detailed information about their personal risk. The health of their baby was major motivating factor. Perceived barriers for physical activity included pregnancy-specific issues such as tiredness and experiencing physical complaints. Insufficient time was a barrier more frequently reported by women with children. Abstaining from snacking was identified as a challenge for the majority of women, especially for those without children. Women preferred to obtain support from their partner, as well as health professionals and valued flexible lifestyle programs.
Conclusions: Healthcare professionals need to inform overweight pregnant women about their personal risk, discuss lifestyle modification and assist in weight management. Lifestyle programs should be tailored to the individual, taking into account barriers experienced by overweight first-time mothers and multipara women
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
Cost-effectiveness of healthy eating and/or physical activity promotion in pregnant women at increased risk of gestational diabetes mellitus
__Background:__ Gestational diabetes mellitus (GDM) is associated with perinatal health risks to both mother and offspring, and represents a large economic burden. The DALI study is a multicenter randomized controlled trial, undertaken to add to the knowledge base on the effectiveness of interventions for pregnant women at increased risk for GDM. The purpose of this study was to evaluate the cost-effectiveness of the healthy eating and/or physical activity promotion intervention compared to usual care among pregnant women at increased risk of GDM from a societal perspective.
__Methods:__ An economic evaluation was performed alongside a European multicenter-randomized controlled trial. A total of 435 pregnant women at increased risk of GDM in primary and secondary care settings in nine European countries, were recruited and randomly allocated to a healthy eating and physical activity promotion intervention (HE + PA intervention), a healthy eating promotion intervention (HE intervention), or a physical activity promotion intervention (PA intervention). Main outcome measures were gestational weight gain, fasting glucose, insulin resistance (HOMA-IR), quality adjusted life years (QALYs), and societal costs.
__Results:__ Between-group total cost and effect differences were not significant, besides significantly less gestational weight gain in the HE + PA group compared with the usual care group at 35-37 weeks ( 2.3;95%CI:-3.7;-0.9). Cost-effectiveness acceptability curves indicated that the HE + PA intervention was the preferred intervention strategy. At 35-37 weeks, it depends on the decision-makers' willingness to pay per kilogram reduction in gestational weight gain whether the HE + PA intervention is cost-effective for gestational weight gain, whereas it was not cost-effective for fasting glucose and HOMA-IR. After delivery, the HE + PA intervention was cost-effective for QALYs, which was predominantly caused by
Cerebral microbleeds and intracranial haemorrhage risk in patients anticoagulated for atrial fibrillation after acute ischaemic stroke or transient ischaemic attack (CROMIS-2):a multicentre observational cohort study
Background:
Cerebral microbleeds are a potential neuroimaging biomarker of cerebral small vessel diseases that are prone to intracranial bleeding. We aimed to determine whether presence of cerebral microbleeds can identify patients at high risk of symptomatic intracranial haemorrhage when anticoagulated for atrial fibrillation after recent ischaemic stroke or transient ischaemic attack.
Methods:
Our observational, multicentre, prospective inception cohort study recruited adults aged 18 years or older from 79 hospitals in the UK and one in the Netherlands with atrial fibrillation and recent acute ischaemic stroke or transient ischaemic attack, treated with a vitamin K antagonist or direct oral anticoagulant, and followed up for 24 months using general practitioner and patient postal questionnaires, telephone interviews, hospital visits, and National Health Service digital data on hospital admissions or death. We excluded patients if they could not undergo MRI, had a definite contraindication to anticoagulation, or had previously received therapeutic anticoagulation. The primary outcome was symptomatic intracranial haemorrhage occurring at any time before the final follow-up at 24 months. The log-rank test was used to compare rates of intracranial haemorrhage between those with and without cerebral microbleeds. We developed two prediction models using Cox regression: first, including all predictors associated with intracranial haemorrhage at the 20% level in univariable analysis; and second, including cerebral microbleed presence and HAS-BLED score. We then compared these with the HAS-BLED score alone. This study is registered with ClinicalTrials.gov, number NCT02513316.
Findings:
Between Aug 4, 2011, and July 31, 2015, we recruited 1490 participants of whom follow-up data were available for 1447 (97%), over a mean period of 850 days (SD 373; 3366 patient-years). The symptomatic intracranial haemorrhage rate in patients with cerebral microbleeds was 9·8 per 1000 patient-years (95% CI 4·0–20·3) compared with 2·6 per 1000 patient-years (95% CI 1·1–5·4) in those without cerebral microbleeds (adjusted hazard ratio 3·67, 95% CI 1·27–10·60). Compared with the HAS-BLED score alone (C-index 0·41, 95% CI 0·29–0·53), models including cerebral microbleeds and HAS-BLED (0·66, 0·53–0·80) and cerebral microbleeds, diabetes, anticoagulant type, and HAS-BLED (0·74, 0·60–0·88) predicted symptomatic intracranial haemorrhage significantly better (difference in C-index 0·25, 95% CI 0·07–0·43, p=0·0065; and 0·33, 0·14–0·51, p=0·00059, respectively).
Interpretation:
In patients with atrial fibrillation anticoagulated after recent ischaemic stroke or transient ischaemic attack, cerebral microbleed presence is independently associated with symptomatic intracranial haemorrhage risk and could be used to inform anticoagulation decisions. Large-scale collaborative observational cohort analyses are needed to refine and validate intracranial haemorrhage risk scores incorporating cerebral microbleeds to identify patients at risk of net harm from oral anticoagulation.
Funding:
The Stroke Association and the British Heart Foundation
Validation of a Canine Blood Donor Model in Veterinary Nursing Skill Education
Background:
Canine blood donation collection technique is a frequently performed and often life-saving or emergency procedure in small animal critical care. Training student veterinary nurses (SVNs) to correctly perform this clinical technique with confidence involves repetitive training using simulation prior to clinical practice with real patients. Teaching methods including training models used in simulation must undergo validation evaluation to demonstrate suitability for teaching, appropriateness for learning and reliability for assessment, since inappropriately developed models risk incorrect learning with increased confidence.
Summary of Work:
Two canine blood donor simulators were constructed to train SVNs at Dundalk Institute of Technology Ireland, on correct blood donation collection technique as part of transfusion therapy in Critical Care and Medical Nursing modules. Plush canine toys were modified to include jugular veins using infusion lines connected to red tinted fluid bags, representing respective patient blood volumes. A stepwise checklist was developed to guide and assess procedural performance. Eight veterinary nursing (VN) educator colleagues from three Irish VN training programmes participated as experts to evaluate model appropriateness and usefulness. 11 SVNs used the model in Critical Care practical class and of those, six opted into the study to provide feedback and ratings on the models’ validity and suitability for learning. Pre-existing experience in transfusion therapy and confidence levels of SVNs at performing the skill post model use were also assessed.
Take Home Message:
Experts found the models to be suitable for teaching and assessment of correct technical skill performance. Students found the models to be helpful to learn the skill correctly and develop confidence prior to live animal performance. The models are a useful precursor to skill performance in live patients and may have potential value outside of the classroom in training veterinary staff to promote clinical effectiveness and patient safety via procedural error identification and reduction
The Effectiveness of Hopeful Mind Program among Primary School Children in Malaysia: A Preliminary Study
The increasing prevalence of mental disorders among children warrant an investigation to evaluate the effectiveness of mental health prevention program to help children dealing with life challenges effectively. A quasi-experimental pre prevention-post prevention research design was conducted to evaluate the effectiveness of Hopeful Mind program among primary school children in Malaysia. Sixty-nine primary school children aged 10-11 participated in this study. Thirty-seven of them were randomly assigned in prevention group and 32 of them were assigned in control group. Results showed that the depressive symptoms for the prevention groups decreased significantly. The prevention group showed a significant improvement in their negative emotional regulation and in controlling their emotions. Results also showed some significant findings between genders. Male children reported significant decreased score in depression and gained significant score improvements in emotional control than the female. Thus, the present study suggested that Hopeful Mind program is feasible in supporting Malaysian children in terms of reducing their depressive symptoms, regulating and controlling their emotion. Several limitations and recommendation for future studies were discussed and presented
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