Neuroendocrine and Psychosocial Consequences of Childhood Acute Lymphoblastic Leukemia and Lymphoma

Kaspers, G.J.L. [Promotor]Gemke, R.J.B.J. [Promotor]Rotteveel, J. [Copromotor

Hypothalamic-pituitary-adrenal axis function in survivors of childhood acute lymphoblastic leukemia and healthy controls

Item does not contain fulltextOf all malignancies in children, acute lymphoblastic leukemia (ALL) is the most common type. Since survival significantly improves over time, treatment-related side effects become increasingly important. Glucocorticoids play an important role in the treatment of ALL, but they may suppress the hypothalamic-pituitary-adrenal (HPA) axis. The duration of HPA axis suppression is not yet well defined. The present study aimed at assessing the function of the HPA axis by determining the cortisol awakening response (CAR) and the dexamethasone (DEX) suppression test in children that were treated for childhood ALL, compared to a healthy age and sex matched reference group. In addition, questionnaires regarding sleep, fatigue, depression and quality of life were completed by the children and their parents. Fourty-three survivors who finished their treatment for childhood ALL 37 (interquartile range 22-75) months before and 57 healthy controls were included. No differences in CAR were observed between ALL survivors and the reference group, but survivors of ALL had higher morning cortisol levels and an increased cortisol suppression in response to oral dexamethasone. Higher cortisol levels in childhood ALL survivors were associated with more fatigue and poorer quality of life. We conclude that the experience of a stressful life event in the past may have caused a long-term dysregulation of the HPA axis in childhood ALL survivors, as reflected in an increased cortisol production and an enhanced negative feedback mechanism.1 september 201

Convergent and construct validity and test–retest reliability of the Caen Chronotype Questionnaire in six languages

Chronotype questionnaires provide a simple and time-effective approach to assessing individual differences in circadian variations. Chronotype questionnaires traditionally focused on one dimension of chronotype, namely its orientation along a continuum of morningness and eveningness. The Caen Chronotype Questionnaire (CCQ) was developed to assess an additional dimension of chronotype that captures the extent to which individual functioning varies during the day (amplitude). The aim of this study was to provide a multilanguage validation of the CCQ in six world regions (Arabic, Dutch, German, Italian, Portuguese and Spanish). At Time 1, a total of 2788 participants agreed to take part in the study (Arabic, n = 731; Dutch, n = 538; German, n = 329; Italian, n = 473; Portuguese, n = 361; Spanish, n = 356). Participants completed an assessment of the CCQ together with the Morningness-Eveningness Questionnaire (MEQ; Horne & Ostberg 1976) as well as questions related to factors theoretically related to chronotype (age, shift work, physical activity, sleep parameters and coffee consumption). One month later, participants again completed the CCQ. Results showed that the two-factor structure (morningness-eveningness and amplitude) of the CCQ could be replicated in all six languages. However, measurement invariance could not be assumed regarding the factor loadings across languages, meaning that items loaded more on their factors in some translations than in others. Test–retest reliability of the CCQ ranged from unacceptable (German version) to excellent (Dutch, Portuguese). Convergent validity was established through small–medium effect size correlations between the morningness-eveningness dimension of the CCQ and the MEQ. Taken together, our findings generally support the use of the translated versions of the CCQ. Further validation work on the CCQ is required including convergent validation against physiological markers of sleep, health and well-being.Scopu

A Taxonomy of SME E-Commerce Platforms Derived from a MarketLevel Analysis

Copyright © 2018 Christopher P. Holland and Manuela Gutiérrez-Leefmans.Published with license by Taylor & Francis. Small and medium-size enterprises (SMEs) constitute a large and important sector of the U.S. and U.K. economies and e-commerce platforms have evolved that are designed specifically to help small business owners and entrepreneurs. Despite the popularity and importance of these digital platforms, there is a paucity of research in this area. This article contributes to theory by being the first study to map out the competitive landscape of SME e-commerce platforms in two markets using a theoretical framework and analysis that is based on business model and strategic group theories. In total, 144 platforms were analyzed using an online panel data methodology, which identified 32 leading SME e-commerce platforms in the UK and United States. These leading platforms were analyzed at the market level using cluster analysis based on strategic group theory and website content analysis. A taxonomy is proposed based on theoretical constructs derived from business model theory: value proposition, Web 2.0 sophistication, and revenue model. Five distinctive strategic groups are identified: information laggards, basic networking, advanced networking, advanced networking mature, and social media markets. The study further outlines managerial implications for SMEs, SME e-commerce platform providers, and external sponsors of the platforms—predominantly government organizations and banks