From multiple perspectives to shared understanding

The aim of this study was to explore how learners operating in a small group reach shared understanding as they work out joint research questions and build a theoretical framework and to identify the resources and tools they used in the process. The learners’ own interpretations of their group activities and learning were also taken into account. The data, consisting of group discussions and the documents produced by the group, were subjected to a qualitative content analysis. The group members employed a variety of resources and tools to exchange their individual perspectives and achieve shared understanding. Summaries of relevant literature laid a foundation for the group’s theoretical discussions. Reflective comparisons between their book knowledge and their personal experiences of online interaction and collaboration were frequent, suggesting that such juxtapositions may have enhanced their learning by intertwining the content to be mastered and the activities entailed by this particular content

Beta-delayed-neutron studies of 135,136^{135,136}Sb and 140^{140}I performed with trapped ions

Beta-delayed-neutron ($\beta$n) spectroscopy was performed using the Beta-decay Paul Trap and an array of radiation detectors. The $\beta$n branching ratios and energy spectra for $^{135,136}$Sb and $^{140}$I were obtained by measuring the time of flight of recoil ions emerging from the trapped ion cloud. These nuclei are located at the edge of an isotopic region identified as having $\beta$n branching ratios that impact the r-process abundance pattern around the A~130 peak. For $^{135,136}$Sb and $^{140}$I, $\beta$n branching ratios of 14.6(11)%, 17.6(28)%, and 7.6(28)% were determined, respectively. The $\beta$n energy spectra obtained for $^{135}$Sb and $^{140}$I are compared with results from direct neutron measurements, and the $\beta$n energy spectrum for $^{136}$Sb has been measured for the first time

Validation of self-reported anthropometrics in the Adventist Health Study 2

<p>Abstract</p> <p>Background</p> <p>Relying on self-reported anthropometric data is often the only feasible way of studying large populations. In this context, there are no studies assessing the validity of anthropometrics in a mostly vegetarian population. The objective of this study was to evaluate the validity of self-reported anthropometrics in the Adventist Health Study 2 (AHS-2).</p> <p>Methods</p> <p>We selected a representative sample of 911 participants of AHS-2, a cohort of over 96,000 adult Adventists in the USA and Canada. Then we compared their measured weight and height with those self-reported at baseline. We calculated the validity of the anthropometrics as continuous variables, and as categorical variables for the definition of obesity.</p> <p>Results</p> <p>On average, participants underestimated their weight by 0.20 kg, and overestimated their height by 1.57 cm resulting in underestimation of body mass index (BMI) by 0.61 kg/m². The agreement between self-reported and measured BMI (as a continuous variable), as estimated by intraclass correlation coefficient, was 0.97. The sensitivity of self-reported BMI to detect obesity was 0.81, the specificity 0.97, the predictive positive value 0.93, the predictive negative value 0.92, and the Kappa index 0.81. The percentage of absolute agreement for each category of BMI (normoweight, overweight, and obese) was 83.4%. After multivariate analyses, predictors of differences between self-reported and measured BMI were obesity, soy consumption and the type of dietary pattern.</p> <p>Conclusions</p> <p>Self-reported anthropometric data showed high validity in a representative subsample of the AHS-2 being valid enough to be used in epidemiological studies, although it can lead to some underestimation of obesity.</p

Non linear pseudo-bosons versus hidden Hermiticity. II: The case of unbounded operators

Parallels between the notions of nonlinear pseudobosons and of an apparent non-Hermiticity of observables as shown in paper I (arXiv: 1109.0605) are demonstrated to survive the transition to the quantum models based on the use of unbounded metric in the Hilbert space of states.Comment: 21 p

Low-lying level structure of 56^{56}Cu and its implications on the rp process

The low-lying energy levels of proton-rich $^{56}$Cu have been extracted using in-beam $\gamma$-ray spectroscopy with the state-of-the-art $\gamma$-ray tracking array GRETINA in conjunction with the S800 spectrograph at the National Superconducting Cyclotron Laboratory at Michigan State University. Excited states in $^{56}$Cu serve as resonances in the $^{55}$Ni(p,$\gamma$)$^{56}$Cu reaction, which is a part of the rp-process in type I x-ray bursts. To resolve existing ambiguities in the reaction Q-value, a more localized IMME mass fit is used resulting in $Q=639\pm82$~keV. We derive the first experimentally-constrained thermonuclear reaction rate for $^{55}$Ni(p,$\gamma$)$^{56}$Cu. We find that, with this new rate, the rp-process may bypass the $^{56}$Ni waiting point via the $^{55}$Ni(p,$\gamma$) reaction for typical x-ray burst conditions with a branching of up to $\sim$40$\%$. We also identify additional nuclear physics uncertainties that need to be addressed before drawing final conclusions about the rp-process reaction flow in the $^{56}$Ni region.Comment: 8 pages, accepted for Phys. Rev.

IShTAR: a test facility to study the interaction between RF wave and edge plasmas

International audienceExistence of high electric fields near an RF antenna launcher causes a number of parasitic phenomena, such as arcing and impurity release, which seriously deteriorate the performance of an ICRF heating scheme in fusion devices. Limited accessibility of the near antenna region in large-scale fusion experiments significantly complicates the associated experimental studies. The IShTAR (Ion Sheath Test Arrangement) test facility has been developed with the requirement to provide a better accessibility and diagnosability of plasmas in the direct vicinity of an ICRF antenna. The purpose of this work is to give a detailed description on the experimental setup and the available diagnostics. Furthermore the paper will demonstrate the capability of the experiment to study phenomena near an ICRF antenna launcher which are relevant for large-scale fusion ICRH systems