2,893 research outputs found
Introduction of interactive learning into French university physics classrooms
We report on a project to introduce interactive learning strategies (ILS) to
physics classes at the Universit\'e Pierre et Marie Curie (UPMC), one of the
leading science universities in France. In Spring 2012, instructors in two
large introductory classes, first-year, second-semester mechanics, and
second-year introductory E&M, enrolling approximately 500 and 250 students
respectively, introduced ILS into some sections of each class. The specific ILS
utilized were Think-Pair-Share questions and Peer Instruction in the main
lecture classrooms, and UW Tutorials for Introductory Physics in recitation
sections. Pre- and post-instruction assessments (FCI and CSEM respectively)
were given, along with a series of demographics questions. We were able to
compare the results of the FCI and CSEM between interactive and non-interactive
classes taught simultaneously with the same curriculum. We also analyzed final
exam results, as well as the results of student and instructor attitude surveys
between classes. In our analysis, we argue that Multiple Linear Regression
modeling is superior to other common analysis tools, including normalized gain.
Our results show that ILS are effective at improving student learning by all
measures used: research-validated concept inventories and final exam scores, on
both conceptual and traditional problem-solving questions. Multiple Linear
Regression analysis reveals that interactivity in the classroom is a
significant predictor of student learning, showing a similar or stronger
relationship with student learning than such ascribed characteristics as
parents' education, and achieved characteristics such as GPA and hours studied
per week. Analysis of student and instructors attitudes shows that both groups
believe that ILS improve student learning in the physics classroom, and
increases student engagement and motivation
Exchange Fluctuation Theorem for correlated quantum systems
We extend the Exchange Fluctuation Theorem for energy exchange between
thermal quantum systems beyond the assumption of molecular chaos, and describe
the non-equilibrium exchange dynamics of correlated quantum states. The
relation quantifies how the tendency for systems to equilibrate is modified in
high-correlation environments. Our results elucidate the role of measurement
disturbance for such scenarios. We show a simple application by finding a
semi-classical maximum work theorem in the presence of correlations.Comment: Lots of new material added, a figure, and a new author, 13 pages, 1
figure, comments welcom
Contamination potential of tar sand exploitation in the western Niger-Delta of Nigeria: baseline studies
Exploitation of the tar sands in Ondo State in
the Niger Delta is likely to result in some environmental
contamination and adversely affect the living conditions of
the farmers and fishermen in the area. Three wells were
established where samples were taken at 1, 2 and 3 m
depth. Although no hydrocarbon contamination was
detected in the water from the surface and boreholes, saline
intrusion was recorded. This study produces a baseline
against which future contamination can be monitored so
that preventative measures can be taken to mitigate the
effects
Cellular location and activity of Escherichia coli RecG proteins shed light on the function of its structurally unresolved C-terminus
RecG is a DNA translocase encoded by most species of bacteria. The Escherichia coli protein targets branched DNA substrates and drives the unwinding and rewinding of DNA strands. Its ability to remodel replication forks and to genetically interact with PriA protein have led to the idea that it plays an important role in securing faithful genome duplication. Here we report that RecG co-localises with sites of DNA replication and identify conserved arginine and tryptophan residues near its C-terminus that are needed for this localisation. We establish that the extreme C-terminus, which is not resolved in the crystal structure, is vital for DNA unwinding but not for DNA binding. Substituting an alanine for a highly conserved tyrosine near the very end results in a substantial reduction in the ability to unwind replication fork and Holliday junction structures but has no effect on substrate affinity. Deleting or substituting the terminal alanine causes an even greater reduction in unwinding activity, which is somewhat surprising as this residue is not uniformly present in closely related RecG proteins. More significantly, the extreme C-terminal mutations have little effect on localisation. Mutations that do prevent localisation result in only a slight reduction in the capacity for DNA repair. © 2014 The Author(s)
Association of Allelic Variation in Genes Mediating Aspects of Energy Homeostasis with Weight Gain during Administration of Antipsychotic Drugs (CATIE Study)
Antipsychotic drugs are widely used in treating schizophrenia, bipolar disorder, and other psychiatric disorders. Many of these drugs, despite their therapeutic advantages, substantially increase body weight. We assessed the association of alleles of 31 genes implicated in body weight regulation with weight gain among patients being treated with specific antipsychotic medications in the clinical antipsychotic trials in intervention effectiveness study, we found that rs2237988 in Potassium Channel Inwardly Rectifying Subfamily J Member 11 (KCNJ11), rs13269119 in Solute carrier family 30 member 8 (SLC30A8), and rs9922047 in fat mass and obesity associated (FTO) were associated with percent weight gain. We also observed the significant interaction of rs11643744 by treatment effect on the weight gain
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Neural Network Modeling of the Lithium/Thionyl Chloride Battery System
Battery systems have traditionally relied on extensive build and test procedures for product realization. Analytical models have been developed to diminish this reliance, but have only been partially successful in consistently predicting the performance of battery systems. The complex set of interacting physical and chemical processes within battery systems has made the development of analytical models a significant challenge. Advanced simulation tools are needed to more accurately model battery systems which will reduce the time and cost required for product realization. Sandia has initiated an advanced model-based design strategy to battery systems, beginning with the performance of lithiumhhionyl chloride cells. As an alternative approach, we have begun development of cell performance modeling using non-phenomenological models for battery systems based on artificial neural networks (ANNs). ANNs are inductive models for simulating input/output mappings with certain advantages over phenomenological models, particularly for complex systems. Among these advantages is the ability to avoid making measurements of hard to determine physical parameters or having to understand cell processes sufficiently to write mathematical functions describing their behavior. For example, ANN models are also being studied for simulating complex physical processes within the Li/SOC12 cell, such as the time and temperature dependence of the anode interracial resistance. ANNs have been shown to provide a very robust and computationally efficient simulation tool for predicting voltage and capacity output for Li/SOC12 cells under a variety of operating conditions. The ANN modeling approach should be applicable to a wide variety of battery chemistries, including rechargeable systems
Joint system quantum descriptions arising from local quantumness
Bipartite correlations generated by non-signalling physical systems that
admit a finite-dimensional local quantum description cannot exceed the quantum
limits, i.e., they can always be interpreted as distant measurements of a
bipartite quantum state. Here we consider the effect of dropping the assumption
of finite dimensionality. Remarkably, we find that the same result holds
provided that we relax the tensor structure of space-like separated
measurements to mere commutativity. We argue why an extension of this result to
tensor representations seems unlikely
The Distribution of the Elements in the Galactic Disk III. A Reconsideration of Cepheids from l = 30 to 250 Degrees
This paper reports on the spectroscopic investigation of 238 Cepheids in the
northern sky. Of these stars, about 150 are new to the study of the galactic
abundance gradient. These new Cepheids bring the total number of Cepheids
involved in abundance distribution studies to over 400. In this work we also
consider systematics between various studies and also those which result from
the choice of models. We find systematic variations exist at the 0.06 dex level
both between studies and model atmospheres. In order to control the systematic
effects our final gradients depend only on abundances derived herein. A simple
linear fit to the Cepheid data from 398 stars yields a gradient d[Fe/H]/dRG =
-0.062 \pm 0.002 dex/kpc which is in good agreement with previously determined
values. We have also reexamined the region of the "metallicity island" of Luck
et al. (2006). With the doubling of the sample in that region and our
internally consistent abundances, we find there is scant evidence for a
distinct island. We also find in our sample the first reported Cepheid (V1033
Cyg) with a pronounced Li feature. The Li abundance is consistent with the star
being on its red-ward pass towards the first giant branch.Comment: 66 pages including tables, 12 figures, Accepted Astronomical Journa
Influence of dynamic river stage on the vulnerability of water wells and structure foundations in cold regions
This research was undertaken thanks, in part, with support from the Global Water Futures Program funded by the Canada First Research Excellence Fund (CFREF)Groundwater is important for people in Northern Canada, yet the groundwater protection protocols and water well vulnerability assessments designed for other warmer regions of Canada may not be applicable to communities in Northern Canada due to the unique hydrogeological characteristics there. The seasonal melt of snow and ice leads to intense river stage fluctuations and might cause flood issues to the adjacent floodplain; however, their influences on the vulnerability of drinking water wells and nearby infrastructure are not fully understood. This research considers a case study at Carmacks, central Yukon, where an integrated surface-subsurface numerical modelling code was used to examine these processes. The model results indicate that the annual variation in the river stage temporarily reverses the direction of the hydraulic gradient between the surface water body and the adjacent aquifer. Stream reaches that gain groundwater under lower river stages can become losing streams during the high stage periods, which facilitates the transport of solute from the river to the adjacent aquifer. Additionally, the model shows that the annual river stage variation can temporarily alter the size and orientation of the region that contributes water to pumping wells, which means new environmental threats could become important. In terms of travel time, the model results suggest that annual river stage variation accelerates the transport of river-origin solutes to the adjacent aquifer, and higher river peaks facilitate more rapid solute migration. Thus, the natural protection of the soil travel path against microbial pathogens may become inefficient and water wells may become more vulnerable. The model results also demonstrate that higher peak river stages are more likely to cause basement inundation at buildings on the riverbank than an average peaks, and that the duration of basement inundation varies at different locations.Engineering Research Council of Canada (NSERC) || Government of Yukon || Global Water Futures (Canada First Research Excellence Fund
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