1,720,999 research outputs found
Functional connectivity changes of the locus coeruleus in Alzheimer’s Disease
No full textGrowing evidence indicates neurone loss in the Locus Coeruleus (LC) in patients with Alzheimer’s Disease (AD). The wide projection and rich connectivity of the LC with multiple brain regions and its interaction with different neural networks suggests the importance of investigating the functional connectivity of the LC, an area of research which has been less studied. The primary aim of this study was to test for differences in functional connectivity of the LC between AD subjects and matched controls using neuromelanin-sensitive MRI (NM-MRI). The secondary aim of this study was to investigate the change in the resting state networks in AD. Pre-processing of the fMRI and structural MRI data from 23 AD subjects and 23 Controls was completed using the FMRIB Software Library (FSL). The images were skull-stripped, registered, and normalised. LC masks were created from the NM-MRI also using FSL. The subsequent data was processed using the CONN toolbox. Seed-to-voxel and ROI-ROI analysis were used to produce connectivity maps and comparisons were conducted between AD and Controls, Left and Right LC, Mild and Moderate AD, and resting state networks. In comparison to Controls, AD subjects had reduced LC connectivity in the subcallosal (p-FDR=0.016417), increased LC connectivity in the right supramarginal and postcentral gyri (p-FDR=0.000002), and reduced connectivity in the default mode network (p-FDR=0.000286) and sensorimotor network (p-FDR=0.027524). The left LC in the AD subjects had a decreased number of significant connections to the amygdala and vermis, compared to the right LC. The number of significant LC connections decreased with progression from controls to mild AD to moderate AD. This study provides new evidence of reduced LC connectivity in AD patients and asymmetrical reduction in the LC skewed towards the left LC. LC connectivity reduction could indicate pathogenesis and progression of AD, aiding prediction of disease progression and development of novel intervention targets
Residual vegetation importance to net CO2 uptake in pine-dominated stands following mountain pine beetle attack in British Columbia, Canada
No full textAn unprecedented epidemic of mountain pine beetle (MPB: Dendroctonus ponderosae) has resulted in extensive mortality of lodgepole pine (Pinus contorta var. latifolia) across British Columbia. The goal of this study was to quantify the contribution of residual live vegetation to forest-level daytime gross ecosystem photosynthesis (GEP) as measured by EC flux-towers in two lodgepole pine-dominated forests during and/or after MPB-attack. Diurnal foliar net photosynthesis (p(n)) of residual live herb, shrub, and tree foliage was measured periodically at both sites throughout the growing seasons of 2007, 2008, and 2009. There were no consistent trends in pn across years at either site for conifer or broadleaf components. The weighted average growing season pn of all components, normalized for LAI of the component, were similar to the average growing-season flux-tower estimates of GEP. Non-rectangular hyperbolic relationships between instantaneous values of p(n) and photosynthetically active radiation (Q) provided the best-fit models for pn. These relationships were used to scale up to stand level by using half-hourly values of Q and measurements of the leaf area of vegetation components to provide modelled estimates of the vertical stand components and their summed ecosystem-scale net photosynthesis (P-N ECOSYSTEM). P-N ECOSYSTEM was similar to GEP at MPB-06 for both half-hourly and daily averages. At MPB-03, daily average estimates of P-N ECOSYSTEM agreed very well with GEP estimates, but half-hourly averages were consistently underestimated in the morning compared to GEP in all 3 years. Understory non-tree species (termed broadleaf vegetation component) were responsible for the majority (65-68%) of P-N ECOSYSTEM at MPB-03, and about one-third (33-35%) at MPB-06. Thus, residual vegetation, and particularly broadleaf species, is very important to growing-season CO2 uptake in MPB-attacked pine stands in central British Columbia and cannot be neglected in larger scale modelling of forest carbon dynamics in these locations. Management of forests in this region should take into account the importance of CO2 uptake by live residual vegetation in helping to mitigate forest management impacts on rising atmospheric CO2 concentrations. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Brown, Mathew
No full textSee entry in Greene County, volume 2, page 35: https://digital.archives.alabama.gov/digital/collection/voter1867/id/357
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