Due to unplanned maintenance of the back-end systems supporting article purchase on Cambridge Core, we have taken the decision to temporarily suspend article purchase for the foreseeable future. We apologise for any inconvenience caused whilst we work with the relevant teams to restore this service.
To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Transcatheter stent implantation has been employed to treat re-coarctation of the aorta in adolescents and young adults. The aim of this work is to use computational fluid dynamics to characterise haemodynamics associated with re-coarctation involving an aneurysmal ductal ampulla and aortic isthmus narrowing, which created minimal pressure drop, and to incorporate computational fluid dynamics’s findings into decision-making concerning catheter-directed treatment.
Computational fluid dynamics permits numerically solving the Navier–Stokes equations governing pulsatile flow in the aorta, based on patient-specific data. We determined flow-velocity fields, wall shear stresses, oscillatory shear indices, and particle stream traces, which cannot be ascertained from catheterisation data or magnetic resonance imaging.
Computational fluid dynamics showed that, as flow entered the isthmus, it separated from the aortic wall, and created vortices leading to re-circulating low-velocity flow that induced low and multidirectional wall shear stress, which could sustain platelet-mediated thrombus formation in the ampulla. In contrast, as flow exited the isthmus, it created a jet leading to high-velocity flow that induced high and unidirectional wall shear stress, which could eventually undermine the wall of the descending aorta.
We used computational fluid dynamics to study re-coarctation involving an aneurysmal ductal ampulla and aortic isthmus narrowing. Despite minimal pressure drop, computational fluid dynamics identified flow patterns that would place the patient at risk for: thromboembolic events, rupture of the ampulla, and impaired descending aortic wall integrity. Thus, catheter-directed stenting was undertaken and proved successful. Computational fluid dynamics yielded important information, not only about the case presented, but about the complementary role it can serve in the management of patients with complex aortic arch obstruction.
The aim of this paper is to examine Canadian key informants’ perceptions of intrapersonal (within an individual) and interpersonal (among individuals) factors that influence successful primary care and public health collaboration.
Primary health care systems can be strengthened by building stronger collaborations between primary care and public health. Although there is literature that explores interpersonal factors that can influence successful inter-organizational collaborations, a few of them have specifically explored primary care and public health collaboration. Furthermore, no papers were found that considered factors at the intrapersonal level. This paper aims to explore these gaps in a Canadian context.
This interpretative descriptive study involved key informants (service providers, managers, directors, and policy makers) who participated in one h telephone interviews to explore their perceptions of influences on successful primary care and public health collaboration. Transcripts were analyzed using NVivo 9.
A total of 74 participants [from the provinces of British Columbia (n=20); Ontario (n=19); Nova Scotia (n=21), and representatives from other provinces or national organizations (n=14)] participated. Five interpersonal factors were found that influenced public health and primary care collaborations including: (1) trusting and inclusive relationships; (2) shared values, beliefs and attitudes; (3) role clarity; (4) effective communication; and (5) decision processes. There were two influencing factors found at the intrapersonal level: (1) personal qualities, skills and knowledge; and (2) personal values, beliefs, and attitudes. A few differences were found across the three core provinces involved. There were several complex interactions identified among all inter and intra personal influencing factors: One key factor – effective communication – interacted with all of them. Results support and extend our understanding of what influences successful primary care and public health collaboration at these levels and are important considerations in building and sustaining primary care and public health collaborations.
Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990–1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.
Introduction: There are limited existing data describing the training methods used to educate tobacco cessation treatment providers around the world.
Aims: To measure the prevalence of tobacco cessation treatment content, skills training, and teaching methods reported by tobacco treatment training programmes around the world.
Methods: Web-based survey in May–September 2013 amongst tobacco cessation training experts across six geographic regions and four World Bank income levels. In total, 104 individual training programmes responded.
Results: Of 104 individual programmes, most reported teaching brief advice (78%) and one-to-one counselling (74%); telephone counselling was uncommon (33%). Overall, teaching of knowledge topics was more commonly reported than skills training. Programmes in lower income countries less often reported teaching about medications, behavioural treatments and biomarkers and less often reported skills-based training about interviewing clients, medication management, biomarker measurement, assessing client outcomes, and assisting clients with co-morbidities. Programmes reported a median 15 hours of training. Face-to-face training was common (85%); online programmes were rare (19%). Almost half (47%) included no learner assessment. Most (65%) offered no continuing education.
Conclusions: Nearly all programmes reported teaching evidence-based treatment modalities in a face-to-face format. Few programmes delivered training online or offered continuing education. Skills-based training was less common amongst low- and middle-income countries (LMICs). There is an unmet need for tobacco treatment training protocols which emphasise practical skills and which are more rapidly scalable than face-to-face training in LMICs.
Approximately half of the variation in wellbeing measures overlaps with variation in personality traits. Studies of non-human primate pedigrees and human twins suggest that this is due to common genetic influences. We tested whether personality polygenic scores for the NEO Five-Factor Inventory (NEO-FFI) domains and for item response theory (IRT) derived extraversion and neuroticism scores predict variance in wellbeing measures. Polygenic scores were based on published genome-wide association (GWA) results in over 17,000 individuals for the NEO-FFI and in over 63,000 for the IRT extraversion and neuroticism traits. The NEO-FFI polygenic scores were used to predict life satisfaction in 7 cohorts, positive affect in 12 cohorts, and general wellbeing in 1 cohort (maximal N = 46,508). Meta-analysis of these results showed no significant association between NEO-FFI personality polygenic scores and the wellbeing measures. IRT extraversion and neuroticism polygenic scores were used to predict life satisfaction and positive affect in almost 37,000 individuals from UK Biobank. Significant positive associations (effect sizes <0.05%) were observed between the extraversion polygenic score and wellbeing measures, and a negative association was observed between the polygenic neuroticism score and life satisfaction. Furthermore, using GWA data, genetic correlations of -0.49 and -0.55 were estimated between neuroticism with life satisfaction and positive affect, respectively. The moderate genetic correlation between neuroticism and wellbeing is in line with twin research showing that genetic influences on wellbeing are also shared with other independent personality domains.
We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years of age was 397,466. As expected, first-born twins had greater birth weight than second-born twins. With respect to height, first-born twins were slightly taller than second-born twins in childhood. After adjusting the results for birth weight, the birth order differences decreased and were no longer statistically significant. First-born twins had greater BMI than the second-born twins over childhood and adolescence. After adjusting the results for birth weight, birth order was still associated with BMI until 12 years of age. No interaction effect between birth order and zygosity was found. Only limited evidence was found that birth order influenced variances of height or BMI. The results were similar among boys and girls and also in MZ and DZ twins. Overall, the differences in height and BMI between first- and second-born twins were modest even in early childhood, while adjustment for birth weight reduced the birth order differences but did not remove them for BMI.
A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m2 in childhood and adolescence and up to 0.2 kg/m2 in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.
For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically (1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and (2) to study the effects of birth-related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects, including both monozygotic (MZ) and dizygotic (DZ) twins, using various sources. We asked for individual level data on height and weight including repeated measurements, birth related traits, background variables, education and smoking. By the end of 2014, 48 projects participated. Together, we have 893,458 height and weight measures (52% females) from 434,723 twin individuals, including 201,192 complete twin pairs (40% monozygotic, 40% same-sex dizygotic and 20% opposite-sex dizygotic) representing 22 countries. This project demonstrates that large-scale international twin studies are feasible and can promote the use of existing data for novel research purposes.
Homocysteine-lowering nutrients may have preventive/ameliorative roles in
To test whether long-term B-vitamin/folate supplementation reduces
Participants were 4331 women (mean age 63.6 years), without prior
depression, from the Women's Antioxidant and Folic Acid Cardiovascular
Study – a randomised controlled trial of cardiovascular disease
prevention among 5442 women. Participants were randomly assigned to
receive a combination of folic acid (2.5mg/d), vitamin B6
(50mg/d) and vitamin B12 (1 mg/d) or a matching placebo.
Average treatment duration was 7 years. The outcome was incident
depression, defined as self-reported physician/clinician-diagnosed
depression or clinically significant depressive symptoms.
There were 524 incident cases. There was no difference between active
v. placebo groups in depression risk (adjusted
relative risk 1.02, 95% CI 0.86–1.21, P = 0.81), despite
significant homocysteine level reduction.
Long-term, high-dose, daily supplementation with folic acid and vitamins
B6 and B12 did not reduce overall depression
risk in mid-life and older women.
Understanding physical processes in near-zero accumulation areas can help us to better understand polar ice-core records, particularly during periods when accumulation rates were lower than today. We report measurements from a 5 m firn core from the Allan Hills, Antarctica, which include physical properties using computer tomography, stable isotope ratios δD and δ18O, and 210Pb activity. The core shows a highly metamorphosed firn with homogeneous and stable structure, but with discrete layers near the surface. The observed firn structure is caused by a combination of unique depositional and post-depositional processes. The irregular δD and δ18O signal does not follow the stratigraphic sequence and implies post-depositional modification caused by microscopic pressure gradients in the firn that can result from either forced ventilation over rough surfaces in the presence of wind or alternating temperature-gradients between the firn and the atmosphere. Our results also indicate impact snow deposition under high winds and with a high initial density and air exchange between the atmosphere and the snowpack.210Pb activity below 0.3 m falls below the detection limit, implying that most of the core is more than 100 years old. We conclude that the Allan Hills record provides a unique opportunity to investigate important processes that would have affected ice-core records from glacial periods.
Background: Atrial fibrillation (AF) is a cause of ischemic stroke and is associated with recurrence and with acute multi-vessel territory non lacunar stroke. Many cryptogenic strokes could be secondary to undiagnosed paroxystic AF. As left atrium (LA) dilatation is a risk factor of AF, we sought to determine if moderate or severe LA dilatation was associated with multiple vascular territory infarcts on magnetic resonance imaging (MRI) in patients with acute ischemic stroke without known AF. Normal LA diameter values are ≤4.0 cm for men and ≤3.8 for women. Methods: Patients who presented at our center between 2006 and 2011 with a diagnosis of acute ischemic stroke (AIS) or transient ischemick attack (TIA) who had a transthoracic echocardiography and a brain MRI were included. Patients with known or de novo AF diagnosed within 3 months of the event were excluded. The main outcome was the presence of acute multi-vessel territory infarct(s) on MRI.Results: 356 patients were included. The mean LA diameter was 37 mm in the control group (normal or mildly dilated LA) and 49 mm in those with moderately to severely enlarged LA (p<0.001). More patients in the LA dilatation group met the main outcome (20% vs 6%; OR 3.89; 95% CI 1.32-11.43; p=0.0014). Conclusions: LA dilatation (at least moderate) is associated with acute non lacunar multiple vascular territory infarcts on MRI in patients with AIS or TIA without known AF or a confirmed diagnosis of AF. Further studies are necessary to determine if this population might benefit from anticoagulation therapy.
The sea urchin Diadema africanum is considered a key
herbivore in sublittoral ecosystems of the Canary Islands. Spatial and
temporal variability in population structure was carried out at Gran
Canaria. We performed a morphometric and population density analysis during
2005, 2006 and 2007 at four sites in zones of Gran Canaria. The study
considered a vertical gradient (5, 10 and 20 m depth) during both seasons,
the cold season (February and March) and the warm season (October and
November). The sea urchin D. africanum in Gran Canaria
exhibited an overall density of 7.59 ± 2.92 urchin m−2. A two-way
ANOVA evidenced spatial differences in mean abundance of the species, while
seasonality was not relevant. The vertical analysis of the abundance of
D. africanum showed differences, the smaller sizes
appeared at greater depths. The Aristotle's lantern width decreased in a
vertical gradient, being remarkable between 10 and 20 m. Findings of
uniformity in size over time, a stable range of high densities and the lack
of a relationship between the size of the sea urchins and the season reveals
that the density–size strategy displayed by D. africanum
which explains in turns the high stability of the urchin barrens, which,
once developed, remain as areas of permanent desertification in subtidal
depths throughout the Canary Archipelago.
The purpose of this study was to describe the longitudinal trajectories and bidirectional relationships of the physical-social and emotional functioning (EF) dimensions of positive aging and to identify their baseline characteristics.
Women age 65 and older who enrolled in one or more Women's Health Initiative clinical trials (WHI CTs) and who had positive aging indicators measured at baseline and years 1, 3, 6, and 9 were included in these analyses (N = 2281). Analytic strategies included latent class growth modeling to identify longitudinal trajectories and multinomial logistic regression to examine the effects of baseline predictors on these trajectories.
A five-trajectory model was chosen to best represent the data. For Physical-Social Functioning (PSF), trajectory groups included Low Maintainer (8.3%), Mid-Low Improver (10.4%), Medium Decliner (10.7%), Mid-High Maintainer (31.2%), and High Maintainer (39.4%); for EF, trajectories included Low Maintainer (3%), Mid-Low Improver (9%), Medium Decliner (7.7%), Mid-High Maintainer (22.8%), and High Maintainer (57.5%). Cross-classification of the groups of trajectories demonstrated that the impact of a high and stable EF on PSF might be greater than the reverse. Low depression symptoms, low pain, and high social support were the most consistent predictors of high EF trajectories.
Aging women are heterogeneous in terms of positive aging indicators for up to 9 years of follow-up. Interventions aimed at promoting sustainable EF might have diffused effects on other domains of healthy aging.
To examine the use of vitamin D supplements during infancy among the participants in an international infant feeding trial.
Information about vitamin D supplementation was collected through a validated FFQ at the age of 2 weeks and monthly between the ages of 1 month and 6 months.
Infants (n 2159) with a biological family member affected by type 1 diabetes and with increased human leucocyte antigen-conferred susceptibility to type 1 diabetes from twelve European countries, the USA, Canada and Australia.
Daily use of vitamin D supplements was common during the first 6 months of life in Northern and Central Europe (>80 % of the infants), with somewhat lower rates observed in Southern Europe (>60 %). In Canada, vitamin D supplementation was more common among exclusively breast-fed than other infants (e.g. 71 % v. 44 % at 6 months of age). Less than 2 % of infants in the USA and Australia received any vitamin D supplementation. Higher gestational age, older maternal age and longer maternal education were study-wide associated with greater use of vitamin D supplements.
Most of the infants received vitamin D supplements during the first 6 months of life in the European countries, whereas in Canada only half and in the USA and Australia very few were given supplementation.
Genome-wide association analysis on monozygotic twin-pairs offers a route to discovery of gene–environment interactions through testing for variability loci associated with sensitivity to individual environment/lifestyle. We present a genome-wide scan of loci associated with intra-pair differences in serum lipid and apolipoprotein levels. We report data for 1,720 monozygotic female twin-pairs from GenomEUtwin project with 2.5 million SNPs, imputed or genotyped, and measured serum lipid fractions for both twins. We found one locus associated with intra-pair differences in high-density lipoprotein cholesterol, rs2483058 in an intron of SRGAP2, where twins carrying the C allele are more sensitive to environmental factors (P = 3.98 × 10−8). We followed up the association in further genotyped monozygotic twins (N = 1,261), which showed a moderate association for the variant (P = 0.200, same direction of an effect). In addition, we report a new association on the level of apolipoprotein A-II (P = 4.03 × 10−8).