106 research outputs found
Reengaging High School Dropouts: Early Results of the National Guard Youth ChalleNGe Program Evaluation
Very early results from a random assignment evaluation of the National Guard Youth ChalleNGe Program, an intensive, "quasi-military" residential program for high school dropouts, show that the program has large impacts on high school diploma and GED attainment and positive effects on working, college-going, health, self-efficacy, and avoiding arrest
Frequency and surface dependence of the mechanical loss in fused silica
We have compiled measurements of the mechanical loss in fused silica from
samples spanning a wide range of geometries and resonant frequency in order to
model the known variation of the loss with frequency and surface-to-volume
ratio. This improved understanding of the mechanical loss has contributed
significantly to the design of advanced interferometric gravitational wave
detectors, which require ultra-low loss materials for their test mass mirrors.Comment: 5 pages, 3 figure but 5 figure file
Examining the Effects of Gender and Presentation Mode on Learning from a Multimedia Presentation
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Visual presentation modes in multimedia learning include pictures, video, and animations. Research also reveals cognitive differences between males and females (Halpern, 2004). Which one of the presentation modes is more effective? Can one of these presentation modes be more effective for a specific gender? This study aimed to investigate the role of gender and presentation mode in multimedia learning. Participants were 72 university students randomly assigned to one of the two different versions of a computer-based multimedia program (narration with animation vs. narration with static images). A 2 × 2 factorial design is created by crossing gender and presentation mode (animation vs. static image). Dependent measures consisted of a transfer and a comprehension test. The results showed a significant modality by gender interaction on the comprehension test. Females performed better studying animations, whereas males performed better studying static pictures. The results are interpreted in light of multimedia learning principles and studies in the area of gender differences in learning. The important contribution of this study is the suggestion that individual differences such as gender should be considered in multimedia learning
Stochastic resonance and heat fluctuations in a driven double-well system
We study a periodically driven (symmetric as well as asymmetric)double-well
potential system at finite temperature. We show that mean heat loss by the
system to the environment(bath) per period of the applied field is a good
quantifier of stochastic resonance. It is found that the heat fluctuations over
a single period are always larger than the work fluctuations. The observed
distributions of work and heat exhibit pronounced asymmetry near resonance. The
heat losses over a large number of periods satisfies the conventional
steady-state fluctuation theorem, though different relation exists for this
quantity.Comment: modified version, 10 figure
Pathways to care for Long COVID and for long-term conditions from patients' and clinicians' perspective
Itk Negatively Regulates Induction of  T Cell Proliferation by CD28 Costimulation
CD28 is a cell surface molecule that mediates a costimulatory signal crucial for T cell proliferation and lymphokine production. The signal transduction mechanisms of CD28 are not well understood. Itk, a nonreceptor protein tyrosine kinase specifically expressed in T cells and mast cells, has been implicated in the CD28 signaling pathway because of reports that it becomes phosphorylated on tyrosines and associates with CD28 upon cross-linking of the cell surface molecule. To determine whether Itk plays a functional role in CD28 signaling, we compared T cells from Itk-deficient mice and control mice for their responses to CD28 costimulation. T cells defective in Itk were found to be fully competent to respond to costimulation. Whereas the CD3-mediated proliferative response was severely compromised in the absence of Itk, the calcineurin-independent CD28-mediated response was significantly elevated when compared with cells from control animals. The augmented proliferation was not due to increased production of interleukin-2. The results suggest that Itk has distinct roles in the CD3 versus the CD28 signaling pathways. By negatively regulating the amplitude of signaling upon CD28 costimulation, Itk may provide a means for modulating the outcome of T cell activation during development and during antigen-driven immune responses
Lineage Diversion of T Cell Receptor Transgenic Thymocytes Revealed by Lineage Fate Mapping
Background: The binding of the T cell receptor (TCR) to major histocompatibility complex (MHC) molecules in the thymus determines fates of lymphocytes that subsequently home to secondary lymphoid tissue. TCR transgenic models have been used to study thymic selection and lineage commitment. Most TCR transgenic mice express the rearranged prematurely at the double negative stage and abnormal TCRαβ populations of T cells that are not easily detected in non-transgenic mice have been found in secondary lymphoid tissue of TCR transgenic mice. Methodology and Principal Findings: To determine developmental pathways of TCR-transgenic thymocytes, we used Cre-LoxP-mediated fate mapping and show here that premature expression of a transgenic diverts some developing thymocytes to a developmental pathway which resembles that of gamma delta cells. We found that most peripheral T cells with the HY-TCR in male mice have bypassed the RORγt-positive (double positive, DP) stage to accumulate either as (double negative, DN) or as T cells in lymph nodes or gut epithelium. Likewise, DN cells in lymphoid tissue of female mice were not derived from DP thymocytes. Conclusion: The results further support the hypothesis that the premature expression of the can divert DN thymocytes into gamma delta lineage cells
Energy fluctuations in a biharmonically driven nonlinear system
We study the fluctuations of work done and dissipated heat of a Brownian
particle in a symmetric double well system. The system is driven by two
periodic input signals that rock the potential simultaneously. Confinement in
one preferred well can be achieved by modulating the relative phase between the
drives. We show that in the presence of pumping the stochastic resonance signal
is enhanced when analyzed in terms of the average work done on the system per
cycle. This is in contrast to the case when pumping is achieved by applying an
external static bias, which degrades resonance. We analyze the nature of work
and heat fluctuations and show that the steady state fluctuation theorem holds
in this system.Comment: 13 pages, 14 figures, revised manuscrip
Classical and Thermodynamic work fluctuations
We have studied the nature of classical work () and thermodynamic work
() fluctuations in systems driven out of equilibrium both in transient and
time periodic steady state. As the observation time of trajectory increases, we
show that the number of trajectories which exhibit excursions away from the
typical behaviour i.e., , and dissipated heat
decreases as anticipated for macroscopic time scales. Analytical expressions
for such trajectories are obtained. Trajectory for which may not
correspond to or . The applicability of steady state
fluctuation theorems are discussed in our linear as well as nonlinear models.Comment: Based on the talk presented by Mamata Sahoo at the Condensed Matter
Days-Aug. 2008 held at Viswavarati University, Kolkata. 19 pages, 8 figure
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