15,305 research outputs found
The Best for Last: The Timing of U.S. Supreme Court Decisions
This Article investigates the hypothesis that the most important and, often, controversial and divisive cases—so called big cases—are disproportionately decided at the end of June. We define a big case in one of four ways: front-page coverage in the New York Times; front-page and other coverage in four national newspapers (the New York Times, Los Angeles Times, Washington Post, and Chicago Tribune); the number of amicus curiae briefs filed in a case; and the number of subsequent citations by the Supreme Court to its decision in a case. We find a statistically significant association between each measure of a big case and end-of-term decisions even after controlling for the month of oral argument (cases argued later in the term are more likely to be decided near the end of the term) and case attributes (e.g., dissents and concurrences) that increase the time it takes to decide a case. We also speculate on why big cases cluster at the end of the term. One possibility is legacy and reputational concerns: when writing what they think will be a major decision, the Justices and their law clerks take more time polishing until the last minute with the hope of promoting their reputations. Another is that the end-of-term clustering of the most important cases may tend to diffuse media coverage of and other commentary regarding any particular case, and thus spare the Justices unwanted criticism just before they leave Washington for their summer recess
Can disorder enhance incoherent exciton diffusion?
Recent experiments aimed at probing the dynamics of excitons have revealed
that semiconducting films composed of disordered molecular subunits, unlike
expectations for their perfectly ordered counterparts, can exhibit a
time-dependent diffusivity in which the effective early time diffusion constant
is larger than that of the steady state. This observation has led to
speculation about what role, if any, microscopic disorder may play in enhancing
exciton transport properties. In this article, we present the results of a
model study aimed at addressing this point. Specifically, we present a general
model, based upon F\"orster theory, for incoherent exciton diffusion in a
material composed of independent molecular subunits with static energetic
disorder. Energetic disorder leads to heterogeneity in molecule-to-molecule
transition rates which we demonstrate has two important consequences related to
exciton transport. First, the distribution of local site-specific diffusivity
is broadened in a manner that results in a decrease in average exciton
diffusivity relative to that in a perfectly ordered film. Second, since
excitons prefer to make transitions that are downhill in energy, the steady
state distribution of exciton energies is biased towards low energy molecular
subunits, those that exhibit reduced diffusivity relative to a perfectly
ordered film. These effects combine to reduce the net diffusivity in a manner
that is time dependent and grows more pronounced as disorder is increased.
Notably, however, we demonstrate that the presence of energetic disorder can
give rise to a population of molecular subunits with exciton transfer rates
exceeding that of subunits in an energetically uniform material. Such
enhancements may play an important role in processes that are sensitive to
molecular-scale fluctuations in exciton density field.Comment: 15 pages, 3 figure
Nonequilibrium dynamics of localized and delocalized excitons in colloidal quantum dot solids
Self-assembled quantum dot (QD) solids are a highly tunable class of
materials with a wide range of applications in solid-state electronics and
optoelectronic devices. In this perspective, we highlight how the presence of
microscopic disorder in these materials can influence their macroscopic
optoelectronic properties. Specifically, we consider the dynamics of excitons
in energetically disordered QD solids using a theoretical model framework for
both localized and delocalized excitonic regimes. In both cases, we emphasize
the tendency of energetic disorder to promote nonequilibrium relaxation
dynamics and discuss how the signatures of these nonequilibrium effects
manifest in time-dependent spectral measurements. Moreover, we describe the
connection between the microscopic dynamics of excitons within the material and
the measurement of material specific parameters, such as emission linewidth
broadening and energetic dissipation rate.Comment: 4 figure
fMRI biomarkers of social cognitive skills training in psychosis: Extrinsic and intrinsic functional connectivity.
Social cognitive skills training interventions for psychotic disorders have shown improvement in social cognitive performance tasks, but little was known about brain-based biomarkers linked to treatment effects. In this pilot study, we examined whether social cognitive skills training could modulate extrinsic and intrinsic functional connectivity in psychosis using functional magnetic resonance imaging (fMRI). Twenty-six chronic outpatients with psychotic disorders were recruited from either a Social Cognitive Skills Training (SCST) or an activity- and time-matched control intervention. At baseline and the end of intervention (12 weeks), participants completed two social cognitive tasks: a Facial Affect Matching task and a Mental State Attribution Task, as well as resting-state fMRI (rs-fMRI). Extrinsic functional connectivity was assessed using psychophysiological interaction (PPI) with amygdala and temporo-parietal junction as a seed region for the Facial Affect Matching Task and the Mental State Attribution task, respectively. Intrinsic functional connectivity was assessed with independent component analysis on rs-fMRI, with a focus on the default mode network (DMN). During the Facial Affect Matching task, we observed stronger PPI connectivity in the SCST group after intervention (compared to baseline), but no treatment-related change in the Control group. Neither group showed treatment-related changes in PPI connectivity during the Mental State Attribution task. During rs-fMRI, we found treatment-related changes in the DMN in the SCST group, but not in Control group. This study found that social cognitive skills training modulated both extrinsic and intrinsic functional connectivity in individuals with psychotic disorders after a 12-week intervention. These findings suggest treatment-related changes in functional connectivity as a potential brain-based biomarker of social cognitive skills training
ILR Impact Brief - Community College Websites and Barriers to Access
[Excerpt] Community colleges, on average, serve 335 students with disabilities, although that number climbs to 5,000 at the largest college surveyed for this project. Nearly all community colleges that participated in the survey rely on the web for a variety of student services, but only half have instituted requirements regarding web accessibility for individuals with disabilities. Actual evaluations of accessibility and ease of use revealed that none of the websites analyzed complied with all federal standards on accessibility, and many web pages encompassed usability obstacles (e.g., unfamiliar terminology, unintuitive navigation schemes, and hard-to-read design elements) that affected disabled and non-disabled individuals alike
Web-Based Student Processes at Community Colleges: Removing Barriers to Access
Colleges and universities are making extensive use of the Internet for collecting admission and financial aid applications. Benefits from online application services are enjoyed by both the educational institution and the prospec¬tive student who applies online. It is vital that web sites offering these services be made accessible so that students with disabilities are afforded the same benefits of online applications as their non-disabled peers.
Cornell University’s Employment and Disability Institute was funded by the U.S. Department of Education’s National Institute on Disability and Rehabilitation Research (NIDRR) to conduct a project with the following three objectives: 1) survey student services professionals at community colleges to examine the extent of use of the internet for providing services and the awareness of internet accessibility issues, 2) evaluate a sample of community college websites for accessibility and usability by students with and without disabilities, and 3) develop a toolkit for improving access to internet-based services at community colleges
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