Schematising activities in early childhood education

The purpose of this study was to determine the importance of introducing schematising to children in early childhood and to determine whether schematising can be taught to children. This was done using a longitudinal, quantitative study with a quasi-experimental design (N = 133). In this study, the use of schematising was taught to an experimental group of children to determine if it is possible to realise significantly improved results in schematising tasks for an experimental group in comparison to a control group of children who were not taught schematising. Pupils in the experimental group demonstrated significantly better results on schematising, which cannot be explained by maturation. In our future research, we will investigate the mathematical performances of these experimental and control groups in the next grade of the primary school curriculum. © 2009 Taylor & Francis

Effecten van het leren schematiserenvan jonge leerlingen op hun latere prestaties in het reken-wiskundeonderwijs.

Dit artikel betreft een anderhalf jaar durend experimenteel onderzoek naar het leren schematiseren van jonge kinderen en de effecten hiervan op hun latere leerresultaten in het reken-wiskundeonderwijs. Leerlingen in de experimentele groep participeerden in een programma waarin het schematiseren expliciet werd onderwezen en begeleid. In de controlegroep werd geen specifieke aandacht besteed aan het schematiseren. De vraagstelling was: Wat zijn de effecten van een experimentele interventie gericht op het leren schematiseren van jonge kinderen (groep 2 basisschool) op hun latere leerresultaten bij rekenwiskunde (groep 3)? Er werden vijf toetsen afgenomen om de wiskundige ontwikkeling in kaart te brengen. Na de interventieperiode werd aan de hand van een speciaal ontwikkelde toets vastgesteld of het mogelijk is om leerlingen op deze jonge leeftijd te leren schematiseren. Vervolgens is een analyse uitgevoerd naar de effecten van het programma op de latere wiskundige prestaties van de leerlingen zoals gemeten met Cito-toetsen. Het onderzoek toont aan dat jonge kinderen kunnen leren schematiseren en dat het experimentele programma een significant positief effect heeft op hun prestaties bij rekenwiskunde. Ruim een jaar na de interventie werd een retentietoets afgenomen. Hieruit bleek echter dat op dat moment geen verschil meer kon worden aangetoond tussen de experimentele en controle leerlingen. In de discussie wordt ingegaan op deze uitkomsten en worden suggesties gedaan voor vervolgonderzoek

Dispersion γZ\gamma Z-box correction to the weak charge of the proton

We consider elastic scattering of electrons off a proton target. The parity violating (PV) asymmetry arises at leading order in $\alpha$ due to interference of $\gamma$ and $Z$ exchange. The radiative corrections to this leading mechanism were calculated in the literature and included in experimental analyses, except for $\gamma Z$ box and cross-box contributions. We present here a dispersion calculation of these corrections in forward kinematics. We demonstrate that at the GeV energies of current PV experiments, such corrections are not suppressed by the small vector weak charge of the electron, as occurs in the atomic PV. Our results suggest that the current theoretical uncertainty in the analysis of the QWEAK experiment might be substantially underestimated, and more accurate account of the dispersion corrections are needed in order to interprete the PV data.Comment: 4 pages, 3 figures, revtex

Are representations to be provided or generated in primary mathematics education? Effects on transfer

With regard to transfer, is it better to provide pupils with ready-made representations or is it more effective to scaffold pupils' thinking in the process of generating their own representations with the help of peers and under the guidance of a teacher in a process of guided co-construction? The sample comprises 10 classes and 239 Grade 5 primary school students, age 10-11 years. A pretest-posttest control group research design was used. In the experimental condition, pupils were taught to construct representations collaboratively as a tool in the learning of percentages and graphs. Children in the experimental condition outperformed control children on the posttest and transfer test. Both high- and low-achieving pupils profited from the intervention. This study shows that children who learn to design are in a better position to understand pictures, graphs, and models. They are more successful in solving new, complex mathematical problems

Listening to young children's voices: the evaluation of a coding system

Listening to young children’s voices is an issue with increasing relevance for many researchers in the field of early childhood research. At the same time, teachers and researchers are faced with challenges to provide children with possibilities to express their notions, and to find ways of comprehending children’s voices. In our research we aim to provide a method for listening to, and analyzing young children’s voices on educational issues. In this article we describe a new step in our research in which we are dealing with the issues of validity and reliability for the evaluation of our coding system: is our coding system for analyzing young children’s voices valid and reliable? Escuchar las voces de niños pequeños es un tema de creciente relevancia para muchos investigadores en el campo de estudios sobre la infancia. Al mismo tiempo, profesorado y personal investigador se encuentran con retos para dar a los niños posibilidades de expresar sus nociones y encontrar formas de comprender sus voces. En nuestra investigación nos proponemos proveer un método para escuchar y analizar las voces de los niños acerca de temas educativos. En este artículo describimos un nuevo paso en nuestra investigación en la que estamos trabajando cuestiones de validez y fiabilidad para la evaluación de un sistema de codificación: Es nuestro sistema de codificación para analizar las voces de los niños válido y fiable

Differences in life expectancy between four Western countries and their Caribbean dependencies, 1980–2014

BackgroundIn the Caribbean, life expectancy in politically independent territories has increasingly diverged from that of territories that remained affiliated to their former colonizers. Because these affiliated territories differ in degree of political independence, they are not all governed in the same way. We assessed whether differences in life expectancy trends between Caribbean dependencies and their Western administrators were related to their degree of political independence, and which causes of death contributed to divergence or convergence in life expectancy.MethodsAnalysis of age-standardized death rates and decomposition of life expectancy differences between France, the Netherlands, UK, USA and their Caribbean dependencies by age and cause-of-death during the period 1980–2014.ResultsLife expectancy differences between Western countries and their dependencies have generally increased for men and narrowed for women, but trends have been much more favorable in the French- than in the Dutch-administered territories. The strongest contributions to widening gaps in life expectancy between Western countries and their dependencies were from mortality from cardiovascular diseases (ischemic heart disease) and external causes (homicide and traffic accidents).ConclusionDependencies with a stronger political affiliation to a Western country experienced more favorable life expectancy developments than dependencies that had more autonomy during the 1980–2014 period. The underlying mortality differences with Western countries are largely comparable among Caribbean territories but differ in magnitude, most notably for cardiovascular disease and external causes. This suggests that increases in a territory’s political autonomy impairs the diffusion of new knowledge and techniques, and/or reduces government’s effectiveness in implementing policies

Exploring the reach and program use of Hello World, an email-based health promotion program for pregnant women in the Netherlands

<p>Abstract</p> <p>Background</p> <p>In 2006, the Dutch government initiated Hello World, an email-based program promoting healthy lifestyles among pregnant women through quizzes with pregnancy-related questions. In 2008, an updated version was released.</p> <p>The present study aimed to (1) examine the reach of Hello World and the representativeness of its users for all pregnant women in the Netherlands, (2) explore the relationship between program engagement and lifestyle characteristics, and (3) explore the relationship between the program content participants accessed (content on smoking, physical activity, and nutrition) and their lifestyle characteristics.</p> <p>Methods</p> <p>Data from 4,363 pregnant women were included. After registration, women received an online questionnaire with demographic and lifestyle questions. To evaluate their representativeness, their demographic characteristics were compared with existing data for Dutch (pregnant) women. Women were classified on the following lifestyle characteristics: smoking, nutrition, physical activity, and pre-pregnancy weight status. Program use was tracked and the relationships between lifestyle characteristics, program engagement, and the percentage of smoking, physical activity, and nutrition questions accessed after opening a quiz were explored using Mann–Whitney U tests and Kruskal-Wallis tests.</p> <p>Results</p> <p>Hello World reached ±4% of its target population. Ten percent of participants were low educated and 22% immigrants. On average, women received 6.1 (SD:2.8) quiz emails and opened 32% of the associated quizzes (2.0, SD:2.1). A significant positive association was found between the number of quizzes opened and the number of healthy lifestyle characteristics. After opening a quiz, women accessed most smoking, nutrition, and physical activity questions. Significant relationships were found between several lifestyle characteristics and the percentage of smoking, physical activity, and nutrition questions accessed. However, between-group differences were small, quiz topics were largely unrelated to their lifestyle characteristics, and inconsistencies were found regarding the directions of these associations.</p> <p>Conclusions</p> <p>Hello World reached ±4% of its target population, which is lower than the reach of its previous version (±8%). Relatively few low educated and immigrant women registered for the program. Active participation in the program was positively associated with the number of healthy behaviours participants engaged in. The program content participants chose to access was largely unrelated to their lifestyle characteristics.</p

Mechanical cell-matrix feedback explains pairwise and collective endothelial cell behavior in vitro

In vitro cultures of endothelial cells are a widely used model system of the collective behavior of endothelial cells during vasculogenesis and angiogenesis. When seeded in an extracellular matrix, endothelial cells can form blood vessel-like structures, including vascular networks and sprouts. Endothelial morphogenesis depends on a large number of chemical and mechanical factors, including the compliancy of the extracellular matrix, the available growth factors, the adhesion of cells to the extracellular matrix, cell-cell signaling, etc. Although various computational models have been proposed to explain the role of each of these biochemical and biomechanical effects, the understanding of the mechanisms underlying in vitro angiogenesis is still incomplete. Most explanations focus on predicting the whole vascular network or sprout from the underlying cell behavior, and do not check if the same model also correctly captures the intermediate scale: the pairwise cell-cell interactions or single cell responses to ECM mechanics. Here we show, using a hybrid cellular Potts and finite element computational model, that a single set of biologically plausible rules describing (a) the contractile forces that endothelial cells exert on the ECM, (b) the resulting strains in the extracellular matrix, and (c) the cellular response to the strains, suffices for reproducing the behavior of individual endothelial cells and the interactions of endothelial cell pairs in compliant matrices. With the same set of rules, the model also reproduces network formation from scattered cells, and sprouting from endothelial spheroids. Combining the present mechanical model with aspects of previously proposed mechanical and chemical models may lead to a more complete understanding of in vitro angiogenesis.Comment: 25 pages, 6 figures, accepted for publication in PLoS Computational Biolog

Volume of the cloacal protuberance as an indication of reproductive state in male Blue Tits <i>Cyanistes caeruleus</i>

In male passerines, the accumulation of sperm in the sperm reserves causes the cloaca to become enlarged, forming the cloacal protuberance (CP). In Blue Tits, the timing of breeding differs considerably between pairs. Hence, when catching a male during the breeding season it may be unclear whether he is in a reproductively active state (i.e. producing sperm). Here, we show in captive Blue Tits Cyanistes caeruleus that CP volume is increased in males in a reproductively active state when compared to the same males in a reproductively inactive state. However, there was some overlap in CP volume when comparing the values in reproductively active and non-active states. Measurements of CP volume at a single time point, therefore, do not allow the researcher to reliably determine an individual's reproductive status.