6,024 research outputs found
Ovarian and cervical cancer awareness: development of two validated measurement tools.
The aim of the study was to develop and validate measures of awareness of symptoms and risk factors for ovarian and cervical cancer (Ovarian and Cervical Cancer Awareness Measures)
Large magnetoresistance at room-temperature in semiconducting polymer sandwich devices
We report on the discovery of a large, room temperature magnetoresistance
(MR) effect in polyfluorene sandwich devices in weak magnetic fields. We
characterize this effect and discuss its dependence on voltage, temperature,
film thickness, electrode materials, and (unintentional) impurity
concentration. We usually observed negative MR, but positive MR can also be
achieved under high applied electric fields. The MR effect reaches up to 10% at
fields of 10mT at room temperature. The effect shows only a weak temperature
dependence and is independent of the sign and direction of the magnetic field.
We find that the effect is related to the hole current in the devices.Comment: 3 pages, 4 figure
Universality classes in Burgers turbulence
We establish necessary and sufficient conditions for the shock statistics to
approach self-similar form in Burgers turbulence with L\'{e}vy process initial
data. The proof relies upon an elegant closure theorem of Bertoin and Carraro
and Duchon that reduces the study of shock statistics to Smoluchowski's
coagulation equation with additive kernel, and upon our previous
characterization of the domains of attraction of self-similar solutions for
this equation
Newborns' preference for face-relevant stimuli: effects of contrast polarity
There is currently no agreement as to how specific or general are the mechanisms underlying newborns' face preferences. We address this issue by manipulating the contrast polarity of schematic and naturalistic face-related images and assessing the preferences of newborns. We find that for both schematic and naturalistic face images, the contrast polarity is important. Newborns did not show a preference for an upright face-related image unless it was composed of darker areas around the eyes and mouth. This result is consistent with either sensitivity to the shadowed areas of a face with overhead (natural) illumination and/or to the detection of eye contact
Predictive value of hematological and phenotypical parameters on postchemotherapy leukocyte recovery
Background: Grade IV chemotherapy toxicity is defined as absolute neutrophil count <500/μL. The nadir is considered as the lowest neutrophil number following chemotherapy, and generally is not expected before the 7th day from the start of chemotherapy. The usual prophylactic dose of rHu-G-CSF (Filgrastim) is 300 μg/day, starting 24-48 h after chemotherapy until hematological recovery. However, individual patient response is largely variable, so that rHu-G-CSF doses can be different. The aim of this study was to verify if peripheral blood automated flow cytochemistry and flow cytometry analysis may be helpful in predicting the individual response and saving rHu-G-CSF. Methods: During Grade IV neutropenia, blood counts from 30 cancer patients were analyzed daily by ADVIA 120 automated flow cytochemistry analyzer and by Facscalibur flow cytometer till the nadir. "Large unstained cells" (LUCs), myeloperoxidase index (MPXI), blasts, and various cell subpopulations in the peripheral blood were studied. At nadir rHu-G-CSF was started and 81 chemotherapy cycles were analyzed. Cycles were stratified according to their number and to two dose-levels of rHuG-CSF needed to recovery (300-600 vs. 900-1200 μg) and analyzed in relation to mean values of MPXI and mean absolute number of LUCs in the nadir phase. The linear regressions of LUCs % over time in relation to two dose-levels of rHu-G-CSF and uni-multivariate analysis of lymphocyte subpopulations, CD34+ cells, MPXI, and blasts were also performed. Results: In the nadir phase, the increase of MPXI above the upper limit of normality (>10; median 27.7), characterized a slow hematological recovery. MPXI levels were directly related to the cycle number and inversely related to the absolute number of LUCs and CD34 +/CD45+ cells. A faster hematological recovery was associated with a higher LUC increase per day (0.56% vs. 0.25%), higher blast (median 36.7/μL vs. 19.5/μL) and CD34+/CD45+ cell (median 2.2/μL vs. 0.82/μL) counts. Conclusions: Our study showed that some biological indicators such as MPXI, LUCs, blasts, and CD34 +/CD45+ cells may be of clinical relevance in predicting individual hematological response to rHu-G-CSF. Special attention should be paid when nadir MPXI exceeds the upper limit of normality because the hematological recovery may be delayed. © 2009 Clinical Cytometry Society
Learning Biology through Innovative Curricula: A Comparison of Game- and Nongame-Based Approaches
This study explored student learning in the context of innovative biotechnology curricula and the effects of gaming as a central element of the learning experience. The quasi-experimentally designed study compared learning outcomes between two curricular approaches: one built around a computer-based game and the other built around a narrative case. The research questions addressed student learning of basic biological principles, development of interest in learning science, and how a game-based approach compared to a nongame-based approach in terms of supporting learning. The study employed a pre-post design with 1,888 high school students nested within the classes of 36 biology teachers. Results indicated that students participating in both approaches demonstrated statistically and practically significant gains on both proximal and distal assessments of biological content knowledge. Neither group demonstrated gains in science interest. The curriculum by time interaction was not statistically different, indicating that students in both groups showed similar results. Implications for game-based science learning and future research include building better awareness of technological and professional development challenges associated with implementing educational games, the need for new strategies for understanding the impacts of games for learning, and the need for cost-benefit analyses in the planning of game-based educational approaches
Learning Biology through Innovative Curricula: A Comparison of Game- and Nongame-Based Approaches
This study explored student learning in the context of innovative biotechnology curricula and the effects of gaming as a central element of the learning experience. The quasi-experimentally designed study compared learning outcomes between two curricular approaches: one built around a computer-based game and the other built around a narrative case. The research questions addressed student learning of basic biological principles, development of interest in learning science, and how a game-based approach compared to a nongame-based approach in terms of supporting learning. The study employed a pre-post design with 1,888 high school students nested within the classes of 36 biology teachers. Results indicated that students participating in both approaches demonstrated statistically and practically significant gains on both proximal and distal assessments of biological content knowledge. Neither group demonstrated gains in science interest. The curriculum by time interaction was not statistically different, indicating that students in both groups showed similar results. Implications for game-based science learning and future research include building better awareness of technological and professional development challenges associated with implementing educational games, the need for new strategies for understanding the impacts of games for learning, and the need for cost-benefit analyses in the planning of game-based educational approaches
Learning Biology through Innovative Curricula: A Comparison of Game- and Nongame-Based Approaches
This study explored student learning in the context of innovative biotechnology curricula and the effects of gaming as a central element of the learning experience. The quasi-experimentally designed study compared learning outcomes between two curricular approaches: one built around a computer-based game and the other built around a narrative case. The research questions addressed student learning of basic biological principles, development of interest in learning science, and how a game-based approach compared to a nongame-based approach in terms of supporting learning. The study employed a pre-post design with 1,888 high school students nested within the classes of 36 biology teachers. Results indicated that students participating in both approaches demonstrated statistically and practically significant gains on both proximal and distal assessments of biological content knowledge. Neither group demonstrated gains in science interest. The curriculum by time interaction was not statistically different, indicating that students in both groups showed similar results. Implications for game-based science learning and future research include building better awareness of technological and professional development challenges associated with implementing educational games, the need for new strategies for understanding the impacts of games for learning, and the need for cost-benefit analyses in the planning of game-based educational approaches
Ab initio vibrations in nonequilibrium nanowires
We review recent results on electronic and thermal transport in two different
quasi one-dimensional systems: Silicon nanowires (SiNW) and atomic gold chains.
For SiNW's we compute the ballistic electronic and thermal transport properties
on equal footing, allowing us to make quantitative predictions for the
thermoelectric properties, while for the atomic gold chains we evaluate
microscopically the damping of the vibrations, due to the coupling of the chain
atoms to the modes in the bulk contacts. Both approaches are based on a
combination of density-functional theory, and nonequilibrium Green's functions.Comment: 16 pages, to appear in Progress in Nonequilibrium Green's Functions
IV (PNGF4), Eds. M. Bonitz and K. Baltzer, Glasgow, August 200
Josephson Coupling, Phase Correlations, and Josephson Plasma Resonance in Vortex Liquid Phase
Josephson plasma resonance has been introduced recently as a powerful tool to
probe interlayer Josephson coupling in different regions of the vortex phase
diagram in layered superconductors. In the liquid phase, the high temperature
expansion with respect to the Josephson coupling connects the Josephson plasma
frequency with the phase correlation function. This function, in turn, is
directly related to the pair distribution function of the liquid. We develop a
recipe to extract the phase and density correlation functions from the
dependencies of the plasma resonance frequency and the
axis conductivity on the {\it ab}-component of the
magnetic field at fixed {\it c} -component. Using Langevin dynamic simulations
of two-dimensional vortex arrays we calculate density and phase correlation
functions at different temperatures. Calculated phase correlations describe
very well the experimental angular dependence of the plasma resonance field. We
also demonstrate that in the case of weak damping in the liquid phase,
broadening of the JPR line is caused mainly by random Josephson coupling
arising from the density fluctuations of pancake vortices. In this case the JPR
line has a universal shape, which is determined only by parameters of the
superconductors and temperature.Comment: 22 pages, 6 figures, to appear in Phys. Rev. B, December
- …