6,891 research outputs found
Improved Cardiorespiratory Fitness Is Associated with Increased Cortical Thickness in Mild Cognitive Impairment
Cortical atrophy is a biomarker of Alzheimer’s disease (AD) that correlates with clinical symptoms. This study examined changes in cortical thickness from before to after an exercise intervention in mild cognitive impairment (MCI) and healthy elders. Thirty physically inactive older adults (14 MCI, 16 healthy controls) underwent MRI before and after participating in a 12-week moderate intensity walking intervention. Participants were between the ages of 61 and 88. Change in cardiorespiratory fitness was assessed using residualized scores of the peak rate of oxygen consumption (V̇O2peak) from pre- to post-intervention. Structural magnetic resonance images were processed using FreeSurfer v5.1.0. V̇O2peak increased an average of 8.49%, which was comparable between MCI and healthy elders. Overall, cortical thickness was stable except for a significant decrease in the right fusiform gyrus in both groups. However, improvement in cardiorespiratory fitness due to the intervention (V̇O2peak) was positively correlated with cortical thickness change in the bilateral insula, precentral gyri, precuneus, posterior cingulate, and inferior and superior frontal cortices. Moreover, MCI participants exhibited stronger positive correlations compared to healthy elders in the left insula and superior temporal gyrus. A 12-week moderate intensity walking intervention led to significantly improved fitness in both MCI and healthy elders. Improved V̇O2peak was associated with widespread increased cortical thickness, which was similar between MCI and healthy elders. Thus, regular exercise may be an especially beneficial intervention to counteract cortical atrophy in all risk groups, and may provide protection against future cognitive decline in both healthy elders and MCI
Negative quantum capacitance in graphene nanoribbons with lateral gates
We present numerical simulations of the capacitive coupling between graphene
nanoribbons of various widths and gate electrodes in different configurations.
We compare the influence of lateral metallic or graphene side gate structures
on the overall back gate capacitive coupling. Most interestingly, we find a
complex interplay between quantum capacitance effects in the graphene
nanoribbon and the lateral graphene side gates, giving rise to an
unconventional negative quantum capacitance. The emerging non-linear capacitive
couplings are investigated in detail. The experimentally relevant relative
lever arm, the ratio between the coupling of the different gate structures, is
discussed.Comment: 8 pages, 6 figure
Meteorological application of Apollo photography Final report
Development of meteorological information and parameters based on cloud photographs taken during Apollo 9 fligh
Dewetting of thin polymer films near the glass transition
Dewetting of ultra-thin polymer films near the glass transition exhibits
unexpected front morphologies [G. Reiter, Phys. Rev. Lett., 87, 186101 (2001)].
We present here the first theoretical attempt to understand these features,
focusing on the shear-thinning behaviour of these films. We analyse the profile
of the dewetting film, and characterize the time evolution of the dry region
radius, , and of the rim height, . After a transient time
depending on the initial thickness, grows like while
increases like . Different regimes of growth are
expected, depending on the initial film thickness and experimental time range.Comment: 4 pages, 5 figures Revised version, published in Physical Review
Letters: F. Saulnier, E. Raphael and P.-G. de Gennes, Phys. Rev. Lett. 88,
196101 (2002
The Effect of Emotional Intelligence and Task Type on Malevolent Creativity
Malevolent creativity (MC), or intending to inflict harm in original ways, is an aspect of creativity that has received little empirical attention. It reasons that generating malevolently creative products in response to a problem is dependent upon individual differences and environmental factors, especially with regard to the social and emotional content of a particular problem. A personality variable strongly associated with how individuals acknowledge and respond to such social and emotional content is emotional intelligence (EI). Individuals with higher EI often solve problems in cooperative, beneficial, and positive ways, which seems contrary to solving a problem with MC. In addition to testing whether EI is negatively related to MC in general, we analyzed whether that negative relationship would persist even after controlling for cognitive ability and task effects. Those questions were examined across two studies. Results suggest that individuals with lower EI are more likely to respond to different types of problems with increased instances of MC even when the social or emotional content of those problems are factored out. The implications and limitations of these studies, as well as future directions for the study of MC, are discussed
Transesophageal echocardiographic evaluation of an intraoperative retrograde acute aortic dissection: case report
BACKGROUND: We report an intraoperative retrograde dissection of the aorta and its subsequent evaluation by transesophageal echocardiography (TEE). CASE PRESENTATION: A 78 year old woman with an ascending aortic aneurysm without dissection and coronary artery disease was brought to the operating room for aneurysm repair and coronary artery bypass grafting. After initiation of cardiopulmonary bypass through a femoral artery cannula, aortic dissection was noted and subsequently imaged by TEE. CONCLUSION: Retrograde aortic dissection through the femoral artery is life-threatening. Intraoperative TEE can be used to diagnose this uncommon event, and should be considered after initiation of bypass
Sharing Social Network Data: Differentially Private Estimation of Exponential-Family Random Graph Models
Motivated by a real-life problem of sharing social network data that contain
sensitive personal information, we propose a novel approach to release and
analyze synthetic graphs in order to protect privacy of individual
relationships captured by the social network while maintaining the validity of
statistical results. A case study using a version of the Enron e-mail corpus
dataset demonstrates the application and usefulness of the proposed techniques
in solving the challenging problem of maintaining privacy \emph{and} supporting
open access to network data to ensure reproducibility of existing studies and
discovering new scientific insights that can be obtained by analyzing such
data. We use a simple yet effective randomized response mechanism to generate
synthetic networks under -edge differential privacy, and then use
likelihood based inference for missing data and Markov chain Monte Carlo
techniques to fit exponential-family random graph models to the generated
synthetic networks.Comment: Updated, 39 page
The Interactive Effects of Self-Perceptions and Job Requirements on Creative Problem Solving
Over the years, researchers have focused on ways to facilitate creativity in the workplace by looking at individual factors and organizational factors that affect employee creativity (Woodman, Sawyer, & Griffin, 1993). In many cases, the factors that affect creativity are examined independently. In other words, it is uncommon for researchers to look at the interaction among individual and organizational factors. In this study, it is argued that to get a true understanding of how to maximize creativity in the workplace, organizational researchers must look at the interaction between organizational factors and individual factors that affect employee creativity. More specifically, the current study looked at an individual\u27s perceptions about his or her ability to be creative (i.e., individual factor) and perceptions of requirements for creativity in the workplace (i.e., an organizational factor). The results indicated that individuals who have a high belief about their ability to be creative (an individual factor) were most creative when they also perceived requirements for creativity in the workplace (an organizational factor). Furthermore, individuals who had low perceptions of creative ability were still able to perform creatively when they had high perceptions of requirements for creativity. This suggests that, to maximize creativity, organizations should focus on both individual and organizational factors that affect employee creativity
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