The pick-up of cometary protons by the solar wind

The High Energy Range Spectrometer (HERS) of the Ion Mass Spectrometer on the Giotto spacecraft measured the 3-dimensional distribution of picked-up cometary protons over a distance of approximately 8 million km upstream of the bow shock of Comet Halley. The protons were observed to be elastically scattered out of their original cycloidal trajectories such that they were nonuniformly distributed over a spherical shell in velocity space. The shell radius (relative to its expected radius) and thickness increased as the bow shock was approached. Downstream of the shock, the cometary protons could not be distinguished from the heated solar wind protons

The development, implementation and evaluation of a school-based intervention to promote fruit and vegetable intake among 10-13 year-old European schoolchildren

This thesis describes the development, implementation and evaluation of a school-based intervention to promote fruit and vegetable intake among 10-13 year-old European schoolchildren. The first part of the thesis addresses two determinant studies, a qualitative and a quantitative study, aimed at gaining insight into important and changeable determinants of schoolchildren’s fruit and vegetable intake. Part two describes the systematic development of an evidence-based and theory-driven intervention addressing relevant determinants of schoolchildren’s fruit and vegetable intake, i.e. taste preferences, knowledge of recommended intake levels, availability of fruit and vegetables, and parental influences. The intervention consisted of three components: educational lessons implemented at school, parental involvement and distribution of fruit and vegetables at school and has been implemented during two school years in the Netherlands, Norway and Spain. Part three of this thesis describes both the effect and process evaluation. Effects have been evaluated in a group-randomised trail among 2106 children from 62 schools. In each country schools were randomly assigned to an intervention or control group. The effects of this intervention on schoolchildren’s intake of fruit and vegetables, as well as changes in determinants of intake were assessed by means of validated questionnaires. Both at the short and the longer-term effects positive effects on frequency of fruit and vegetable intake, and portions of fruit intake were found. Besides, more children from the intervention group knew the daily-recommended intake levels for both fruit and vegetables. The short-term effects are associated with the degree of implementation of the lessons at school and degree of schoolchildren’s appreciation of the intervention

Brain-based Learning for Preschoolers

The nineties have been called the Decade of the Brain and the Decade of Education. Because of new technology we know more about the function of the brain than ever before. We now know that, in an enriched environment where a person is actively engaged with their surroundings, the cortex of their brain actually increases. Because a thicker brain cortex produces smarter lab animals, scientists have drawn the inference that the same is true for humans (Jacobs, Schall, Scheibel, 1993). The science of deliberate enrichment, to stimulate the student’s development, is called “brain-based education.” For the preschool child there are fundamentally basic elements that must be a part of their education. These are: helping the preschooler make sense of their world; helping them feel safe and secure; teaching them that learning is fun; and empowering them with a thirst for knowledge that lasts a lifetime. A preschool classroom and environment that uses brain-based education techniques can achieve these elements.Master'sCollege of Arts and Sciences: EducationUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/117770/1/Wind.pd

Nonlinearity and inter- and intra-individual variability in the extent of engagement in self-reflection and its role in second language writing

Self-regulation plays an important role in second language (L2) writing development (Wilby, 2020; Teng & Zhang, 2020). Hence, engagement in self-regulation is of crucial importance for successful writers (Cleary & Zimmerman, 2012). Self-reflection, one of the three phases of self-regulation (Zimmerman, 2000), was found to be the most paramount phase in L2 writing development (Nitta & Baba, 2014). Nevertheless, there is a scarcity of studies investigating engagement in self-reflection and longitudinal L2 writing development. This multiple case-study employed a time-series analysis to explore the temporal and dynamic changes in the extent of engagement in self-reflection and its possible role in L2 writing development. Six Hungarian English as Foreign Language (EFL) learners composed seven argumentative essays over a seven-month period, one in each month. After finishing the compositions, the participants were asked to comment on the quality of their essays. The essays were analysed for linguistic complexity indices, while the interviews were coded for self-reflective comments. This study found that as the six participants became more engaged in self-reflection, slight improvements were detected in linguistic complexity indices over time. However, both engagement in self-reflection and L2 writing development showed nonlinearity and inter- and intra-individual variability over time

Single-Walled Carbon Nanotubes as Shadow Masks for Nanogap Fabrication

We describe a technique for fabricating nanometer-scale gaps in Pt wires on insulating substrates, using individual single-walled carbon nanotubes as shadow masks during metal deposition. More than 80% of the devices display current-voltage dependencies characteristic of direct electron tunneling. Fits to the current-voltage data yield gap widths in the 0.8-2.3 nm range for these devices, dimensions that are well suited for single-molecule transport measurements

Unexpected Scaling of the Performance of Carbon Nanotube Transistors

We show that carbon nanotube transistors exhibit scaling that is qualitatively different than conventional transistors. The performance depends in an unexpected way on both the thickness and the dielectric constant of the gate oxide. Experimental measurements and theoretical calculations provide a consistent understanding of the scaling, which reflects the very different device physics of a Schottky barrier transistor with a quasi-one-dimensional channel contacting a sharp edge. A simple analytic model gives explicit scaling expressions for key device parameters such as subthreshold slope, turn-on voltage, and transconductance.Comment: 4 pages, 4 figure