Cultural Differences in Maternal Beliefs and Behaviors: A Study of Middle-Class Anglo and Puerto Rican Mother-Infant Pairs in Four Everyday Situations

This study examines cultural patterning in situational variability in mother-infant interactions among middle-class Anglo and Puerto Rican mothers and their 12 to 15-month-old firstborn children. Forty mothers were interviewed regarding their long-term socialization goals and childrearing strategies, and videotaped interacting with their infants in four everyday settings: feeding, social play, teaching, and free play. Results suggest that: (1) Anglo mothers place greater emphasis on socialization goals and childrearing strategies consonant with a more individualistic orientation, whereas Puerto Rican mothers place greater focus on goals and strategies consistent with a more sociocentric orientation; (2) coherence was found between mothers' childrearing beliefs and practices, with Puerto Rican mothers more likely to directly structure their infants' behaviors; and (3) situational variability arose in mother-infant interactions, but this variability showed a cultural patterning consistent with mothers' long-term socialization goals and childrearing beliefs.     

Evaluation of wrist and hip sedentary behaviour and moderate-to-vigorous physical activity raw acceleration cutpoints in older adults

Wrist-based accelerometers are now common in assessing physical activity (PA) and sedentary behaviour (SB) in population-based studies, but there is a scarcity of raw acceleration cutpoints in older adults. The study aimed to determine and evaluate wrist-based GENEActiv (GA) and hip-based ActiGraph GT3X+ (AG) raw acceleration cutpoints for SB and moderate-to-vigorous PA (MVPA) in older adults ≥60 years of age. A laboratory-based calibration analyses of 34 healthy older adults involved receiver operator characteristic (ROC) curves to determine raw acceleration cutpoints for SB and MVPA. ROC analysis revealed an area under the curve (AUC) of 0.88 for GA SB and MVPA, and 0.90 for AG SB and 0.94 for AG MVPA. Sensitivity optimised SB and specificity optimised MVPA GA cutpoints of 57 mg and 104 mg, and AG cutpoints of 15 mg and 69 mg were also generated, respectively. Cross-validation analysis revealed moderate agreement for GA and AG SB cutpoints, and fair to substantial agreement for GA and AG MVPA cutpoints, respectively. The resultant cutpoints can classify older adults as engaging in SB or not engaging in MVPA but the sensitivity optimised SB cutpoints should be interpreted with a degree of caution due to their modest cross-validation results.     

The onset of deep recycling of supracrustal materials at the Paleo-Mesoarchean boundary

The recycling of supracrustal materials, and in particular hydrated rocks, has a profound impact on mantle composition and thus on the formation of continental crust, because water modifies the physical properties of lithological systems and the mechanisms of partial melting and fractional fractionation. On the modern Earth, plate tectonics offers an efficient mechanism for mass transport from the Earth''s surface to its interior, but how far this mechanism dates back in the Earth''s history is still uncertain. Here, we use zircon oxygen (O) isotopes to track recycling of supracrustal materials into the magma sources of early Archean igneous suites from the Kaapvaal Craton, southern Africa. The mean δ¹⁸O values of zircon from TTG (tonalite–trondhjemite–granodiorite) rocks abruptly increase at the Paleo-Mesoarchean boundary (ca. 3230 million years ago; Ma), from mantle zircon values of 5‰–6‰ to approaching 7.1‰, and this increase occurs in ≤3230 Ma rocks with elevated Dy/Yb ratios. The ¹⁸O enrichment is a unique signature of low-temperature water–rock interaction on the Earth''s surface. Because the later phase was emplaced into the same crustal level as the older one and TTG magmas would derive from melting processes in the garnet stability field (>40 km depth), we suggest that this evident shift in TTG zircon O isotopic compositions records the onset of recycling of the mafic oceanic crust that underwent seawater hydrothermal alteration at low temperature. The onset of the enhanced recycling of supracrustal materials may also have developed elsewhere in other Archean cratons and reflects a significant change in the tectonic realm during craton formation and stabilization, which may be important processes for the operation of plate tectonics on early Earth.     

Peak Power Assessment of Isokinetic Knee Flexor and Extensor Tests – Pitfalls of a Dynamometer-based Assessment

ABSTRACT

Many sports demand high forces at high movement speeds. Joint power combines these two measures and is frequently analyzed by isokinetic tests. However, various concepts of assessing joint power lead to conflicting results. The aim was to examine different methods to calculate peak power during isokinetic knee tests of sixty-one healthy male participants (20 y, 182 cm, 76 kg). Unilateral movements of the eccentrically working hamstrings and the concentrically working quadriceps at 150°/s were captured by high-speed cameras. Peak power derived from isokinetic data was significantly higher (p < 0.01, d > 1.54) compared to the camera-based kinematic procedures. To achieve best accuracy, peak power should be derived from the camera-based joint angular velocity and the measured moment at time of peak power during the dynamometer’s isokinetic range of motion. A meaningful assessment of isokinetic joint power should incorporate a camera-based kinematic analysis to account for potential measuring inaccuracies owing to anatomical features, axis misalignment, and tissue deformation.     

Developmental changes in item and source memory: evidence from an ERP recognition memory study with children, adolescents, and adults

Event-related potential (ERP) correlates of item and source memory were assessed in 18 children (7-8 years), 20 adolescents (13-14 years), and 20 adults (20-29 years) performing a continuous recognition memory task with object and nonobject stimuli. Memory performance increased with age and was particularly low for source memory in children. The ERP difference between first presentations of objects and nonobjects, reflecting generic novelty processing, showed only small developmental changes. Regarding item memory, adults showed the putative ERP correlates of familiarity and recollection, whereas ERP effects in children and adolescents suggested a strong reliance on recollection. ERP correlates of source memory refined with age, suggesting maturation of strategic recollection between childhood and adolescence and the development of postretrieval control until adulthood.     

A General Approach to Defining Latent Growth Components

We present a 3-step approach to defining latent growth components. In the first step, a measurement model with at least 2 indicators for each time point is formulated to identify measurement error variances and obtain latent variables that are purged from measurement error. In the second step, we use contrast matrices to define the latent growth components representing the constructs of substantive interest. The corresponding matrix of structural coefficients is then computed by inverting the contrast matrix. In the third and last step, the first 2 steps are integrated into a structural equation model. The particular strength of this approach is that it permits construction of latent growth components in such a way that they represent interesting contrasts from a substantive point of view. This is illustrated using data of cancer patients obtained from 3 fatigue scales of the multidimensional fatigue inventory measured at 4 time points.     

Motivational interference in study–leisure conflicts: how opportunity costs affect the self-regulation of university students

We examined the effects of motivational interference resulting from tempting action alternatives among a sample of university students with respect to a new measure of different motivational qualities. Participants imagined themselves in a typical study–leisure conflict and provided information about their internal conflict experience in two scenarios: reading a course paper instead of meeting friends and vice versa. Participants then evaluated intrinsic, mastery, approach, avoidance, and external incentives for both activities. Confirmatory factor analyses yielded good model fits for the proposed five-factor incentive structure. In accordance with the idea of motivational interference, the incentives for meeting friends were positively related to experienced internal conflict while imagining studying, representing opportunity costs of learning. The same pattern was found for the opportunity costs that the participants had experienced while imagining meeting friends. In particular, intrinsic and approach incentives represented incremental opportunity costs of activity engagement, regardless of whether the dismissed activity was related to achievement or leisure. The findings highlight the need to apply a dynamic and context-sensitive perspective on achievement motivation to the context of higher education.     

Forschungs- und Entwicklungsprojekte

Ohne ZusammenfassungAxel Pfeiffer: Dipl.-Ing.,Patentanwalt     

Transition partnerships: the views of education professionals and staff in support services for young people with learning disabilities

Transition to post-statutory education and employment for young people with learning disabilities has become a hotly debated issue among professionals in education and support services in the UK. Partnerships between educational institutions and voluntary sector providers are supposed to be ideal vehicles for delivering transition services and securing outcomes for young people with learning disabilities. In this article, Axel Kaehne and Stephen Bayer of the Welsh Centre for Learning Difficulties report the findings of a survey of the views of special educational needs co-ordinators and professionals who are involved at operational and strategic levels in the work of transition partnerships. The data show that undue emphasis is often placed, by all stakeholders, on the soft, rather than the concrete, outcomes of transition; that smooth transitions are still hampered by insufficient flow of information between collaborating agencies; and that there are still significant gaps in provision, in particular in the supported employment field, due to funding or referral restrictions. To deliver first-class transitions, argue Axel Kaehne and Stephen Bayer, partnerships that support young people with learning disabilities need to address these difficulties with some urgency.