Assessing Consistency of Effects when Applying Multilevel Models to Single-Case Data

In the context of single-case experimental designs, replication is crucial. On the one hand, the replication of the basic effect within a study is necessary for demonstrating experimental control. On the other hand, replication across studies is required for establishing the generality of the intervention effect. Moreover, the "replicability crisis" presents a more general context further emphasizing the need for assessing consistency in replications. In the current text, we focus on replication of effects within a study and we specifically discuss the consistency of effects. Our proposal for assessing the consistency of effects refers to one of the promising data analytical techniques: multilevel models, also known as hierarchical linear models or mixed effects models. One option is to check, for each case in a multiple-baseline design, whether the confidence interval for the individual treatment effect excludes zero. This is relevant for assessing whether the effect is replicated as being non-null. However, we consider that it is more relevant and informative to assess, for each case, whether the confidence interval for the random effects includes zero (i.e., whether the fixed effect estimate is a plausible value for each individual effect). This is relevant for assessing whether the effect is consistent in size, with the additional requirement that the fixed effect itself is different from zero. The proposal for assessing consistency is illustrated with real data and it is implemented in free user-friendly software

Sport activity in adolescence: associations with health perceptions and experimental behaviours

Despite the relevance of this research topic from a public health perspective, there is currently a lack of objective data on European adolescents' sport activity, notably the associations between their sport habits and their health attitudes and behaviours, which may have important consequences both in terms of somatic (cardiovascular) health and mental health. The objective of the present study was to determine the direction and strength of the associations between the frequency of sport and health variables; in particular, perceptions of health, self image, substance use and experimental behaviours. Data were collected as part of the 1993 Swiss Multicentric Adolescent Survey on Health. In this survey, anonymous self-administered questionnaires were distributed to a national representative sample of 10 000 in-school adolescents (15-20 years of age). Univariate analyses explored the relationships between the level of sport activity and health variables; then logistic regression analyses examined the strength of these relationships. According to the results, half of the sample do sports more than twice a week, boys more often as part of a sports club. Differences between non-athletic and athletic adolescents describe the latter as having less somatic complaints, more confidence in their future health, a better body image, a lesser tendency to attempt suicide, a higher frequency of use of the car seat belt, and a lower use of tobacco, wine and marijuana. Links between the frequency of sport activity and the locus of control related to health, general satisfaction with life or sexual behaviours are less strong. It must be noticed that the cross-sectional data collection precludes the establishment of a causal relationship between exercise and health behaviours. However, the existing links underline the coexistence of positive health characteristics and sport activity, suggesting that an incitement to get involved in physical activity may be a necessary component of a comprehensive prevention approach among adolescent

Improved Randomization Tests for a Class of Single-Case Intervention Designs

Forty years ago, Eugene Edgington developed a single-case AB intervention design-and-analysis procedure based on a random determination of the point at which the B phase would start. In the present simulation studies encompassing a variety of AB-type contexts, it is demonstrated that by also randomizing the order in which the A and B phases are administered, a researcher can markedly increase the procedure’s statistical power

An Improved Two Independent-Samples Randomization Test for Single-Case AB-Type Intervention Designs: A 20-Year Journey

Detailed is a 20-year arduous journey to develop a statistically viable two-phase (AB) single-case two independent-samples randomization test procedure. The test is designed to compare the effectiveness of two different interventions that are randomly assigned to cases. In contrast to the unsatisfactory simulation results produced by an earlier proposed randomization test, the present test consistently exhibited acceptable Type I error control under various design and effect-type configurations, while at the same time possessing adequate power to detect moderately sized intervention-difference effects. Selected issues, applications, and a multiple-baseline extension of the two-sample test are discussed

Es descobreix un patró d'ossificació comú en els ungulats

Tots els vertebrats tenim un esquelet ossi. Però la formació dels ossos varia entre individus i entre espècies. Investigadors de la UAB han trobat un patró d'ossificació en els Ungulats, nom genèric de qualsevol mamífer les extremitats del qual acaben en peülles, diferent en funció de si els ossos estan sotmesos a tensions o a pressions. Aquesta nova aproximació pot ser aplicada a l'estudi de fòssils de mamífers extints i ser útil tant per establir relacions filogenètiques de parentiu com per conèixer aspectes funcionals de l'evolució dels vertebrats.Todos los vertebrados tenemos un esqueleto óseo. Pero la formación de los huesos varía entre individuos y entre especies. Investigadores de la UAB han encontrado un patrón de osificación en los Ungulados, nombre genérico de cualquier mamífero cuyas extremidades terminan en pezuñas, diferente en función de si los huesos están sometidos a tensiones o presiones. Esta nueva aproximación puede ser aplicada al estudio de fósiles de mamíferos extintos y ser útil tanto para establecer relaciones filogenéticas de parentesco como para conocer aspectos funcionales de la evolución de los vertebrados

Imaging benign inflammatory syndromes

AbstractBenign mastitis is a rare disease and its management is difficult. The diagnostic challenge is to distinguish it from carcinomatous mastitis. We make a distinction between acute mastitis secondary to an infection, to inflammation around a benign structure or to superficial thrombophlebitis, and chronic, principally plasma cell and idiopathic granulomatous mastitis. Imaging is often non-specific but we need to know and look for certain ultrasound, mammogram or magnetic resonance imaging (MRI) signs to give a pointer as early as possible towards a benign aetiology. A biopsy should be undertaken systematically where there is the slightest diagnostic doubt, to avoid failing to recognise a carcinomatous mastitis

Extraperitoneal laparoscopic para-aortic lymph nodes dissection in obese patients

peer reviewe

Deficiency of the bone mineralization inhibitor NPP1 protects against obesity and diabetes

The emergence of bone as an endocrine regulator has prompted a re-evaluation of the role of bone mineralization factors in the development of metabolic disease. Ectonucleotide pyrophosphatase/phosphodiesterase-1 (NPP1) controls bone mineralization through the generation of pyrophosphate, and levels of NPP1 are elevated both in dermal fibroblast cultures and muscle of individuals with insulin resistance. We investigated the metabolic phenotype associated with impaired bone metabolism in mice lacking the gene that encodes NPP1 (Enpp1−/− mice). Enpp1−/− mice exhibited mildly improved glucose homeostasis on a normal diet but showed a pronounced resistance to obesity and insulin resistance in response to chronic high-fat feeding. Enpp1−/− mice had increased levels of the insulin-sensitizing bone-derived hormone osteocalcin but unchanged insulin signalling within osteoblasts. A fuller understanding of the pathways of NPP1 could inform the development of novel therapeutic strategies for treating insulin resistance