43 research outputs found

    Prevalence and predictors of 6-month exclusive breastfeeding among Canadian women: a national survey

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    <p>Abstract</p> <p>Background</p> <p>In spite of the evidence supporting the importance of breastfeeding during the first year of life, data on breastfeeding practices remain limited in Canada. The study aimed to examine the prevalence and predictors of 6-month exclusive breastfeeding among Canadian women.</p> <p>Methods</p> <p>The analysis was based on the Maternity Experience Survey targeting women aged ≥ 15 years who had singleton live births between February 2006 - May 2006 in the Canadian provinces and November 2005 - February 2006 in the territories. The main outcome was exclusive breastfeeding based on the World Health Organization definition. Socioeconomic, demographic, maternal, pregnancy and delivery related variables were considered for a multivariate logistic regression using stepwise modeling. Bootstrapping was performed to account for the complex sampling design.</p> <p>Results</p> <p>The sample size in this study was 5,615 weighted to represent 66,810 Canadian women. While ever breastfeeding was 90.3%, the 6-month exclusive breastfeeding rate was 13.8%. Based on the regression model, having higher years of education, residing in the Northern territories and Western provinces, living with a partner, having had previous pregnancies, having lower pre-pregnancy body mass index and giving birth at older age were associated with increased likelihood of 6-month exclusive breastfeeding. Moreover, smoking during pregnancy, Caesarean birth, infant's admission to the intensive care unit and maternal employment status before 6 months of infant's age were negatively associated with exclusive breastfeeding. Mothers choosing to deliver at home were more likely to remain exclusively breastfeeding for 6 months (Odds Ratio: 5.29, 95% Confidence Interval: 2.95-9.46).</p> <p>Conclusions</p> <p>The 6-month exclusive breastfeeding rate is low in Canada. The study results constitute the basis for designing interventions that aim to bridge the gap between the current practices of breastfeeding and the World Health Organization recommendation.</p

    Thermal Transport in Micro- and Nanoscale Systems

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    Small-scale (micro-/nanoscale) heat transfer has broad and exciting range of applications. Heat transfer at small scale quite naturally is influenced – sometimes dramatically – with high surface area-to-volume ratios. This in effect means that heat transfer in small-scale devices and systems is influenced by surface treatment and surface morphology. Importantly, interfacial dynamic effects are at least non-negligible, and there is a strong potential to engineer the performance of such devices using the progress in micro- and nanomanufacturing technologies. With this motivation, the emphasis here is on heat conduction and convection. The chapter starts with a broad introduction to Boltzmann transport equation which captures the physics of small-scale heat transport, while also outlining the differences between small-scale transport and classical macroscale heat transport. Among applications, examples are thermoelectric and thermal interface materials where micro- and nanofabrication have led to impressive figure of merits and thermal management performance. Basic of phonon transport and its manipulation through nanostructuring materials are discussed in detail. Small-scale single-phase convection and the crucial role it has played in developing the thermal management solutions for the next generation of electronics and energy-harvesting devices are discussed as the next topic. Features of microcooling platforms and physics of optimized thermal transport using microchannel manifold heat sinks are discussed in detail along with a discussion of how such systems also facilitate use of low-grade, waste heat from data centers and photovoltaic modules. Phase change process and their control using surface micro-/nanostructure are discussed next. Among the feature considered, the first are microscale heat pipes where capillary effects play an important role. Next the role of nanostructures in controlling nucleation and mobility of the discrete phase in two-phase processes, such as boiling, condensation, and icing is explained in great detail. Special emphasis is placed on the limitations of current surface and device manufacture technologies while also outlining the potential ways to overcome them. Lastly, the chapter is concluded with a summary and perspective on future trends and, more importantly, the opportunities for new research and applications in this exciting field

    Parieto-occipital cortex and planning of reaching movements: a transcranial magnetic stimulation study

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    A large amount of evidence supports a role for the parietal and frontal cortex in the planning of reaching movements. Nevertheless, neither the timing of involvement of these areas nor if and how their activity can be influenced by external stimuli has been clarified. The parieto-occipital cortex has been investigated by applying transcranial magnetic stimulation (TMS) at 25% (Time 1), 50% (Time 2) and 75% (Time 3) of the reaction time froma go signal to handmovement.No local effectwas found with Time 1, since pulseswere administered before subjects opened their eyes. Reduction of reaction timewas observed at Time 2 when stimuliwere applied over the anterior occipital lobe, parieto-occipital cortex and posterior parietal cortex. The effect on the posterior parietal cortex reverted when Time 3 was used. The present data confirm the existence, in humans, of a dorso-medial set of areas involved in on-line planning of reaching movements. Moreover, they provide novel evidence on the time course of this involvement. Finally, present data show that it is possible to interact with the flow of activity along this stream by appropriately delivering TMS pulses

    Involvement of ipsilateral parieto-occipital cortex in the planning of reching movements: Evidence by TMS

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    Involvement of the ipsilateral hemisphere during planning of reachingmovements is still matter of debate. While it has beendemonstrated that the contralateral hemisphere is dominant in visuo-motor integration, involvement of the ipsilateral hemisphere has also been proposed. Furthermore, a dominant role for left posterior parietal cortex has been shown in this process, independently of the hand and visual field involved. In this study, the possible involvement of ipsilateral parieto-occipital cortex in planning of reaching movements was investigated by transcranial magnetic stimulation (TMS). TMS was applied on four points of the parietal and occipital cortex at 50% (Time 1), 75% (Time 2) and 90% (Time 3) of reaction time from a go-signal to hand movement. The only effect observedwas an increase in reaction time when a region around the parieto-occipital junction was stimulated at Time 2. These results provide further support to the hypothesis that, in the posterior parietal cortex, planning of reaching movements also relies on the ipsilateral hemisphere, in addition to the contralateral or dominant one

    Dramatic placebo effect of high frequency repetitive TMS in treatment of chronic migraine and medication overuse headache

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    Chronic migraine (CM) is often associated with medication overuse headache (MOH). Few small trials have been conducted on Transcranial Magnetic Stimulation for CM treatment, but results are conflicting. Aim of the study was to investigate the effects of high frequency of repetitive Transcranial Magnetic Stimulation (hf-rTMS) in the dorsolateral prefrontal cortex combined with strongly suggesting to avoid medications overuse in patients suffering with CM and MOH. A six-month single-centre perspective randomized double-blinded study was conducted at the Headache Centre of Trieste. Patients suffering with CM and MOH were randomly enrolled in two groups to receive active hf-rTMS in DLPFC or sham hf-rTMS. Headache days (HD), headache hours (HH) and symptomatic drug intake (SDI) were recorded for 30\u202fdays before the beginning of stimulation (T0) and during the three following months (T3). Disability (MIDAS score) was evaluated at T0 and at the three-month follow-up visit. The primary outcome was the evaluation of reduction of HD. Reduction of SDI, HH and disability were considered as secondary outcomes. Out of 26 patients enrolled, 14 completed the study, 7 underwent hf-rTMS and 7 sham-TMS. There were no significant differences between groups at T0 in demographic data and headache measures. Mean number of HD, HH, SDI, and MIDAS similarly reduced in the two groups. Our study failed in demonstrating that hf-rTMS with detoxification advice could be better than detoxification advice alone in CM treatment. hf-rTMS carries a high potential of inducing placebo effect and this can be usefully leveraged to enhance patients' coping strategies
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