Automated analysis of 3D echocardiography

In this thesis we aim at automating the analysis of 3D echocardiography, mainly targeting the functional analysis of the left ventricle. Manual analysis of these data is cumbersome, time-consuming and is associated with inter-observer and inter-institutional variability. Methods for reconstruction of 3D echocardiographic images from fast rotating ultrasound transducers is presented and methods for analysis of 3D echocardiography in general, using tracking, detection and model-based segmentation techniques to ultimately fully automatically segment the left ventricle for functional analysis. We show that reliable quantification of left ventricular volume and mitral valve displacement can be achieved using the presented techniques.SenterNovem (IOP Beeldverwerking, grant IBVC02003), Dutch Technology Foundation STW (grant 06666)UBL - phd migration 201

WAVE DRAG IN FRONT CRAWL SWIMMING

When swimming at the surface, swimmers will experience wave drag. It is observed that above a certain speed, wave height grows rapidly with further speed increase, suggesting that wave drag cannot be neglected at high speed. Therefore, the magnitude of this component of total drag was estimated. Total drag was decomposed in 2 parts; wave and pressure drag. Assuming wave drag to be negligible below 1.6 m/s, the velocity dependence of pressure drag was assessed by drag determinations at speeds below 1.6 m/s. By subtracting the estimated pressure drag from total drag values measured at higher speeds, wave drag was estimated. At a mean speed of 1.89 m/s, mean wave drag was 11.5 N, amounting to 12.1 % of total drag. These results underline the importance of reducing wave drag by diving under the surface after start and turns

Inventarisatie van het sublitorale wilde mosselbestand in de westelijke Waddenzee in het voorjaar van 2009

In opdracht van de PO2mosselcultuur is in het voorjaar van 2009 het mosselbestand in het sublitoraal van de Westelijke Waddenzee geïnventariseerd. Het onderzoek is uitgevoerd door MARINX en IMARES en heeft plaatsgevonden tussen 9 maart en 9 april 2009. Een aantal gebieden is op voorhand uitgesloten voor visserij. Dit betreft droogvallende gebieden (voor zover geïnventariseerd), de permanent gesloten gebieden (LNV, 2004), de onderzoeksvakken die zijn gesloten ten behoeve van het PRODUS onderzoek en de gebieden die niet worden bevist in het kader van het Convenant en het Visplan (zaadbank in de Vlieter). Het mosselbestand in deze gebieden tezamen is 5.7 Mkg bruto versgewicht. In de niet gesloten gebieden is daarmee een bestand aanwezig van 22.7 Mkg bruto. Daarvan komt 15.9 Mkg voor in voldoende hoge dichtheden om lonend te kunnen worden opgevist. Van deze hoeveelheid kan 10.5 Mkg kan worden geoormerkt als mosselzaad. Het resterende deel van de aanwezige mosselbiomassa bestaat voornamelijk uit halfwasmosselen mosselen (broedval 2007). Eén en ander is in onderstaand overzicht nog eens samengevat

Diagnosing Robotic Swarms 2 (Dr. Swarm2)

Robots are envisioned to work alongside humans. However, humans struggle to interpret the state and goals of a robot. The use of multiple robots further exacerbates this issue. To solve this problem, we propose Dr. Swarm 2, an augmented reality (AR) application built on the Magic Leap. The overlay provides concise information in a manner unachievable with existing methods

Toward the optimal strategy for sustained weight loss in overweight cancer survivors: a systematic review of the literature

Purpose: To gain more insight into the optimal strategy to achieve weight loss and weight loss maintenance in overweight and obese cancer survivors after completion of initial treatment, this systematic review aimed to provide an overview of the literature on intervention effects on weight, to describe intervention components used in effective interventions, to identify and synthesize behaviour change techniques (BCTs) and to assess the frequency with which these BCTs were used in effective interventions. / Methods: Six databases were searched for original research articles describing weight changes in adult overweight cancer survivors after participation in a lifestyle intervention initiated after completion of initial treatment. Two researchers independently screened the retrieved papers and extracted BCTs using the BCT Taxonomy version 1. / Results: Thirty-two papers describing 27 interventions were included. Interventions that were evaluated with a robust study design (n = 8) generally showed <5% weight loss and did not evaluate effects at ≥12 months after intervention completion. Effective interventions promoted both diet and physical activity and used the BCTs ‘goal setting (behaviour)’, ‘action planning’, ‘social support (unspecified)’ and ‘instruction on how to perform the behaviour’. / Conclusions: The results of this first review on intervention components of effective interventions could be used to inform intervention development and showed a need for future publications to report long-term effects, a detailed intervention description and an extensive process evaluation. / Implications for cancer survivors: This study contributed to increasing knowledge on the optimal strategy to achieve weight loss, which is recommended for overweight cancer survivors to improve health outcomes

Reduction in sugar-sweetened beverages is not associated with more water or diet drinks

Objective The Dutch Obesity Intervention in Teenagers (DOiT) is a school-based randomised controlled trial that was effective in decreasing the consumption of sugar-sweetened beverages among adolescents. The present study examined, using mediation analysis, whether this decrease in consumption of sugar-sweetened beverages could be explained by an increase in the consumption of water or diet drinks.Design Participants completed a questionnaire about their beverage consumption at baseline and at 8 months (immediately post-intervention), 12- and 20-month follow-ups. A series of multi-level linear regression analyses were performed to examine water and diet drink consumption as potential mediators of the intervention effect on the consumption of sugar-sweetened beverages.Setting Eighteen Dutch secondary schools.Subjects A total of 747 adolescents (mean age: 12&middot;7 years).Results In addition to the DoiT intervention effect of a reduction in the consumption of sugar-sweetened beverages at 8 months (&minus;284 ml/d; 95 % CI &minus;420, &minus;148) and 12 months (&minus;260 ml/d; 95 % CI &minus;360, &minus;160), there was also a significant reduction in diet drinks at 8 months (&minus;52 ml/d; 95 % CI &minus;89, &minus;16). There was no significant difference in water consumption at any follow-up. The decrease in sugar-sweetened beverage consumption could not be explained by an increase in water or diet drink consumption at any time point.Conclusions Interventions aimed at reducing sugar-sweetened beverage consumption may be effective without changing consumption of other beverages. Reducing sugar-sweetened beverages was, however, a main message of the DOiT intervention. It is possible that a concomitant promotion of water may have resulted in a greater increase in water intake and replacement of sugar-sweetened beverages with water.<br /

The working mechanisms of an environmentally tailored physical activity intervention for older adults: a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to explore the working mechanisms of a computer tailored physical activity intervention for older adults with environmental information compared to a basic tailored intervention without environmental information.</p> <p>Method</p> <p>A clustered randomized controlled trial with two computer tailored interventions and a no-intervention control group was conducted among 1971 adults aged ≥ 50. The two tailored interventions were developed using Intervention Mapping and consisted of three tailored letters delivered over a four-month period. The basic tailored intervention targeted psychosocial determinants alone, while the environmentally tailored intervention additionally targeted environmental determinants, by providing tailored environmental information. Study outcomes were collected with questionnaires at baseline, three and six months and comprised total physical activity (days/week), walking (min/week), cycling (min/week), sports (min/week), environmental perceptions and use and appreciation of the interventions.</p> <p>Results</p> <p>Mediation analyses showed that changes in cycling, sports and total physical activity behaviour induced by the environmentally tailored intervention were mediated by changes in environmental perceptions. Changes in environmental perceptions did not mediate the effect of the basic tailored intervention on behaviour. Compared with the basic tailored intervention, the environmentally tailored intervention significantly improved cycling behaviour (τ = 30.2). Additionally, the tailored letters of the environmentally tailored intervention were better appreciated and used, although these differences did not mediate the intervention effect.</p> <p>Discussion</p> <p>This study gave some first indications of the relevance of environmental perceptions as a determinant of changing physical activity behaviours and the potential effectiveness of providing environmental information as an intervention strategy aimed at enhancing physical activity behaviour among older adults.</p