Onderzoek naar de classificatieaccuratesse van Alzheimer is belangrijk om de ziekte in de toekomst beter te kunnen behandelen. In deze scriptie werden twee structurele MRI-maten geëvalueerd: grijze...Show moreOnderzoek naar de classificatieaccuratesse van Alzheimer is belangrijk om de ziekte in de toekomst beter te kunnen behandelen. In deze scriptie werden twee structurele MRI-maten geëvalueerd: grijze stofdichtheid (48 predictoren) en subcorticale volumes (14 predictoren). Deze scriptie onderzocht wat de toegevoegde waarde van subcorticale volumes bovenop grijze stofdichtheid is. Hierbij werd verwacht dat I) grijze stofdichtheid accurater was voor de classificatie van Alzheimer dan subcorticale volumes, maar dat II) subcorticale volumes nog wel iets zouden toevoegen aan grijze stofdichtheid. Om dit te onderzoeken, is data gebruikt van 249 participanten afkomstig uit twee verschillende studies. 76 participanten hadden de diagnose Alzheimer en de overige 173 participanten waren cognitief gezonde ouderen. Er zijn drie modellen gebruikt: een model van grijze stofdichtheid (48 predictoren), een model van subcorticale volumes (14 predictoren) en een combinatiemodel van grijze stofdichtheid en subcorticale volumes (62 predictoren). Voor alle modellen is een logistische regressieanalyse met geneste kruisvalidatie uitgevoerd. Het model van grijze stofdichtheid had een AUC-waarde van 0.897 en een MGA-waarde van 0.822. Het model van subcorticale volumes had een AUC-waarde van 0.807 en een MGA-waarde van 0.769. Het gecombineerde model had een AUCwaarde van 0.897 en een MGA-waarde van 0.841. De eerste hypothese werd bevestigd, aangezien grijze stofdichtheid belangrijker was voor de classificatieaccuratesse dan subcorticale volumes. De tweede hypothese kon niet worden bevestigd, aangezien subcorticale volumes weinig tot niets lijken toe te voegen aan grijze stofdichtheid voor de classificatieaccuratesse van Alzheimer. Deze kennis kan gebruikt worden om toekomstige classificatiemodellen van Alzheimer te verbeteren.Show less
Due to the COVID-19 pandemic, many activities and platforms have shifted to the virtual realm, including rituals and ceremonies. When it comes to psychedelic rituals, there are several important...Show moreDue to the COVID-19 pandemic, many activities and platforms have shifted to the virtual realm, including rituals and ceremonies. When it comes to psychedelic rituals, there are several important factors to take into account, such as the setting, dosage, and type of substance consumed. This paper examines the effects of virtual ceremonies on psychedelic experiences. The study utilized an online self-report questionnaire that was sent 1-2 days after the ceremony conducted by retreat company Spinoza. The gathered data were analyzed using thematic qualitative analysis. The categorization and themes were agreed upon by two independent researchers. The themes presented relate to the improvement of mental health and physical comfort along with insightful personal journeys. Further evaluation of the research suggested that the findings provide a general idea about the effects of digital format on the psychedelic experience. It has been found that with digital platforms on psychedelic experiences, individuals can experience clarity of unsolved issues, improved self-regulation, as well as improved emotional and mental states.Show less
Inaction inertia occurs when one is less likely to take an attractive opportunity, after refusing an even more attractive opportunity. In their experiment, van Putten and colleagues (2007) tried to...Show moreInaction inertia occurs when one is less likely to take an attractive opportunity, after refusing an even more attractive opportunity. In their experiment, van Putten and colleagues (2007) tried to decouple the inaction inertia effect by using ambiguous information. Their results yielded that ambiguous information did in fact decouple. However, the authors came to these conclusions by using optional stopping and p-hacking. This influenced the reliability of the results, so we decided to replicate this study, for good research practices and because it can give us valuable insight into how decoupling works when given an attractive offer. We made use of the replication recipe of Brandt and colleagues (2014) to conduct the replication.Show less
Disgust, rooted in human evolutionary history, serves as a vital defense mechanism against pathogens, manifesting in varied behaviors. This paper explores the intricate relationship between disgust...Show moreDisgust, rooted in human evolutionary history, serves as a vital defense mechanism against pathogens, manifesting in varied behaviors. This paper explores the intricate relationship between disgust and visual attention, employing the eye-tracking method. Drawing insights from primate studies, habituation, and human facial expressions, the research aims to address three key questions: Does gaze aversion occur in humans when exposed to disgusting stimuli, extending avoidance behavior into the visual domain? Do individuals exhibit prolonged attention to facial area, indicating a social imperative to assess the risk of pathogen contamination? How does gaze aversion change with repeated exposure to disgust-inducing stimuli? The study employs three conditions, including scenes of feces ingestion in the test condition, to assess total looking time. Results reveal significant gaze aversion towards feces as compared to control conditions, supporting the hypothesis of avoidance behavior. Participants displayed prolonged attention to faces during non-disgusting conditions, challenging assumptions about social necessity for risk assessment. Repeated exposure across trials to disgust-inducing stimuli did not significantly alter gaze behavior, highlighting the nuanced nature of responses to aversive stimuli. Discussion of the findings and implications are also addressed.Show less
Het pyrrhonisme is een praktische filosofie die kan leiden tot gemoedsrust. Volgens de oorspronkelijke wijsgeer Pyrrho van Ellis zelf verloopt dit middels uitstel van oordeel omtrent non-evidente...Show moreHet pyrrhonisme is een praktische filosofie die kan leiden tot gemoedsrust. Volgens de oorspronkelijke wijsgeer Pyrrho van Ellis zelf verloopt dit middels uitstel van oordeel omtrent non-evidente zaken. In dit onderzoek is deze eeuwenoude leer onderzocht. De eerste hypothese om deze doctrine te onderzoeken was dat een pyrrhonistische denkwijze positief gecorreleert zou zijn aan gemoedsrust. Daarnaast is de mogelijke invloed van geloof op deze relatie bestudeert. Hiervoor was de verwachting dat de relatie tussen pyrrhonistisch denken en gemoedsrust minder sterk is voor gelovige mensen. Om dit te testen is een testbatterij opgesteld, bestaande uit de Non Evident Questionnaire, Generalized Anxiety Disorder-7 en Perceived Stress Scale. Aan de hand van de responses van 175 deelnemers, bleek de hoofdanalyse niet significant te zijn bij zowel de GAD-7 als de PSS. Uit de moderatie analyse bleek tevens een insignificant effect. Beide hypotheses kunnen dus worden verworpen. Mogelijke verklaringen hiervoor kunnen zijn dat de verkregen data relatief weinig gelovige mensen bevatte en relatief veel transgender mensen, waardoor conclusies voorzichtiger getrokken dienen te worden. Daarnaast waren de stellingen in de NE-Q voornamelijk gericht op hedendaagse onderwerpen, en is wellicht niet geschikt voor het meten van een dergelijk tijdloos construct.Show less
In de huidige studie hebben we onderzoek gedaan naar de invloed van Intolerantie voor Onzekerheid (IU; nervositeit voor het onbekende) op processen zoals (1) zekerheid in het geven van een antwoord...Show moreIn de huidige studie hebben we onderzoek gedaan naar de invloed van Intolerantie voor Onzekerheid (IU; nervositeit voor het onbekende) op processen zoals (1) zekerheid in het geven van een antwoord en (2) reactietijd. Met kennis over mechanismen van IU kunnen we symptomen begrijpen en dagelijkse negatieve gevolgen verminderen. Gedurende het experiment kregen 54 gezonde participanten (37 vrouwen, 17 mannen) tussen de 18-40 jaar neutrale en negatieve afbeeldingen met bijhorende beschrijvingen te zien op twee verschillende dagen met 24 uur ertussen. Specifiek is gekeken naar dag twee, waarbij de participanten bij 75 neutrale en 75 negatieve afbeeldingen moesten aangeven of ze de afbeeldingen hadden gezien op de dag ervoor (oud) of niet (nieuw). Ze gaven aan hoe zeker ze waren over hun antwoord (betrouwbaarheidsbeoordeling; VAS 1-100; oud-nieuw). De reactietijd (ms) van deze respons werd voor beide condities gemeten. Daarna vulden participanten de Intolerance for Uncertainty Scale (IUS) in, bestaande uit 27 stellingen waarbij ze aangaven in welke mate de stelling hen typeert. De data zijn geanalyseerd middels niet-parametrische Friedmantoetsen, RMANCOVA en twee regressieanalyses met verschilscores. Daaruit kwamen de volgende bevindingen. Participanten met meer IU vertoonden minder spreiding in zekerheid van hun antwoord en waren gemiddeld langzamer in beide condities. Los van IU, vertoonden participanten meer spreiding in antwoordzekerheid en waren ze gemiddeld langzamer bij de negatieve dan bij de neutrale afbeeldingen. We concluderen dat IU effect heeft op de antwoordzekerheid en op de reactietijd. Of de getoonde afbeeldingen neutraal of negatief zijn blijkt hierbij niet van invloed.Show less
One of the greatest remaining puzzles in physics is what particle dark matter consists of. For this project, the theory of dark pions is considered, a Hidden Valley model that extends the Standard...Show moreOne of the greatest remaining puzzles in physics is what particle dark matter consists of. For this project, the theory of dark pions is considered, a Hidden Valley model that extends the Standard Model with new, dark particles and a new force, dark QCD. A sensitivity study is performed to determine how many dark pions are expected to be in acceptance of the LHCb detector for Run 2 conditions; the LHCb is well-suited to search for particles in the considered O(1) GeV mass and O(1) - O(100) ps lifetime range. Additionally, a framework has been developed to study the dependence of the sensitivity on a number of theoretical parameters of the dark QCD model, namely the probability to form a dark vector meson instead of a dark pion, the number of colours in dark QCD, the dark QCD scale, and the Higgs mass. It is found that O(100) dark pions are in LHCb acceptance for different track categories, and that the considered the- oretical parameters do not drastically change the number of expected particles (with some small caveats), staying within a difference of about 20%. This is acceptable given the expected experimental uncertainty, showing theory inde- pendent searches for dark pions are possible.Show less
Objective: The period after successfully coming off treatment (SCOT) following a childhood cancer diagnosis is known to be a vulnerable time for parents in which increased levels of distress can...Show moreObjective: The period after successfully coming off treatment (SCOT) following a childhood cancer diagnosis is known to be a vulnerable time for parents in which increased levels of distress can play a significant role. It is important to know more about the distress experienced by parents during this period to determine whether an intervention should be used to help parents return to ‘normal life’. The aim of this study was therefore to gain better understanding of parental distress and factors related to their distress during the first year after their child has successfully completed treatment. Methods: A sample of 283 parents of children who had successfully completed cancer treatment in the previous year were included in this cross-sectional study. These parents, who were part of the SCOT group, were invited to complete the Distress Thermometer for Parents (DT-P) within one year after treatment completion. The DT-P consists of a thermometer score to measure experienced distress and problem domains (practical, social, emotional, physical, cognitive, and parenting). Parents in the SCOT group were compared with parents in the general population (NORM group) to see if their distress levels were higher. In addition, the association between distress and the problem domains and child- or parent-related factors (time since the end of treatment, cancer type, child’s age, parental disease, and perceived support) was examined. Results: Parents (73.9% mothers) in the SCOT group experienced higher levels of distress in the first year after SCOT compared to the general population (fathers SCOT: M=3.5, SD=2.6 vs. fathers NORM: M=2.8, SD=2.5; p=.032; mothers SCOT: M=4.1, SD=2.7 vs. mothers NORM: M=3.5, SD=2.7; p=.001). Emotional (p<.001), practical (p=.016), and physical (p=.005) problems were predictors of higher distress levels. Parents’ perceived support from their environment contributed also to their level of distress (p<.001). Conclusions: Parents of children who have successfully completed cancer treatment experience increased levels of distress in the first year after treatment compared to parents in the general population. There may be value in developing an intervention to ease this transition that specifically addresses their emotional well-being and highlights the importance of their social network during this vulnerable period.Show less
Abstract Introduction. Sickness Presenteeism (SP) describes the phenomenon of going to work despite being ill. As SP might be related to more burnout complaints and lower general health and is...Show moreAbstract Introduction. Sickness Presenteeism (SP) describes the phenomenon of going to work despite being ill. As SP might be related to more burnout complaints and lower general health and is associated with higher job demands and lower job resources, the influences of SP were investigated. The research contributed to previous research by targeting a general, diverse population and by exclusively focusing on health instead of motivational reasons for SP. Further, research that investigated the effects of SP as a moderator between working conditions and health factors was lacking. Thus, this study hypothesized, that higher job demands, and lower job resources increase burnout complaints and decrease general health and that this association is strengthened by SP. Methods. Altogether, 115 participants participated in this correlational study. Job resources and job demands were measured with the Demand-Control-Support questionnaire. A new SP variable was created for this research and tested for internal consistency. Burnout was measured with the Burnout-Assessment-Tool and general health with a one-item question. Two multiple regression analyses were conducted. The first analysis measured if higher job demands, and lower job resources were associated with (more) burnout complaints and how this association was moderated by SP. The second analysis measured the same association but with (lower) general health as an outcome variable. Results. SP did not moderate the relationship between job demands and burnout complaints (p=.20), job resources and burnout complaints (p=.70), job demands and general health (p=.49), and job resources and general health (p=.65). Consequently, all hypotheses were rejected. Job demands were directly related to more burnout complaints (p=.005). Discussion. This study found that high job demands were associated with higher burnout complaints in a general and diverse working population, highlighting the importance of reducing workloads. This study did not find significant SP interaction effects. Possible reasons could be sample size limitations and the statistical test choice. Network analyses might better measure a construct like SP, which includes many control factors and associations. According to this study, it seems that to increase general health and decrease burnout complaints, changing working conditions is more appropriate than addressing worker´s SP.Show less
Background: Individuals with psychotic disorders (PD) often experience cognitive challenges, particularly in executive functioning (EF), crucial for daily functioning. Sleep disruptions, notably...Show moreBackground: Individuals with psychotic disorders (PD) often experience cognitive challenges, particularly in executive functioning (EF), crucial for daily functioning. Sleep disruptions, notably insomnia, are prevalent in PD, worsening symptoms and affecting overall well-being and treatment outcomes. Moreover, individuals with PD frequently engage in cannabis use, which can further impact EF. Gender differences may also play a role in how cannabis affects EF, though findings are varied. This study aims to deepen our understanding of the interplay between insomnia, EF, and cannabis use in PD individuals, while considering gender influences. We hypothesize that higher insomnia rates correlate with poorer EF in PD, with cannabis mediating this relationship. Additionally, we expect gender disparities to influence how cannabis affects EF. This study sheds light on critical factors affecting cognitive function in PD, aiding in tailored intervention strategies. Method: Data were collected from a randomly selected sample of patients (N=262) undergoing treatment at a mental health care clinic in the South-western part of the Netherlands at time of inclusion. Participants, aged between 18 and 65 at inclusion, had a primary diagnosis of a psychotic disorder. The current study utilized data from the Lichamelijke Klachten Vragenlijst (LKV), the Behavior Rating Inventory of Executive Function for Adults (BRIEF-A), and the Measurements in Addictions for Triage and Evaluation (MATE). Results: Significant correlations indicated a moderate positive association between insomnia and EF problems. However, mediation analysis did not support cannabis use as a mediator between insomnia and EF. Gender differences were explored through residual variances analysis, suggesting potential unaccounted factors impacting variability. Model fit indices revealed areas for improvement in explaining variance, warranting further examination and potential adjustments to refine the overall model fit. Conclusion: Higher rates of insomnia were related to higher rates of EF problems. There is no evidence for a mediating effect of cannabis use in this relationship. Gender differences did not seem to play a significant role in the effect of cannabis on EF. Future research should incorporate performance-based tasks alongside self-report measures to improve measurement precision. Future treatments could potentially benefit from incorporating interventions that address insomnia, as this may lead to potential enhancements in executive functioning.Show less
The past decades have shown a rise in skin cancer. This creates the need for prevention and efficient treatment. The most common skin cancer (melanoma) can only be treated when detected early. In...Show moreThe past decades have shown a rise in skin cancer. This creates the need for prevention and efficient treatment. The most common skin cancer (melanoma) can only be treated when detected early. In this thesis we propose a method of increasing awareness for people with a high risk of skin cancer as well as allowing for early detection. Skin cancer is hard to detect, even for experiences healthcare professionals. One of the signals of potential harm full lesions is change over time. We propose to develop an application with which changes in skin lesions can be identified early. By allowing patients to film their body with a mobile phone camera we aim to track the development of lesions. If a patient films their body regularly changes can be detected and the application can urge the patient to consult a dermatologist. In this thesis we explore the possibility of combining the frames of these films into an overview displaying the patients complete back or arm. Combining frames is called stitching. Different stitching techniques found in literature are explored and tested for effectiveness. The optimizations performed are reported and the final result is presented. The location of the different lesions on an overview of the body is needed to show the patient and the healthcare professional where potential harmful lesions are located on the body. This allows for further inspection at the dermatology department.Show less
