1,721,064 research outputs found
Integrating cerebrospinal fluid and [18F]-fluorodeoxyglucose positron emission tomography to diagnose Alzheimer's disease and research its pathophysiological substrates
No full textRevealing the complex interactions and assessing potential integration between biomarkers is essential, especially in the early stages of AD, when biomarker alterations may serve to stage patients throughout the disease spectrum, improve phenotyping, and indicate the likelihood of progression to dementia.
In this research, the integration of [18F]-FDG-PET and CSF biomarkers, two of the most used biomarkers in centers focused on neurocognitive disorders, enabled us to collect evidence on their analytical and diagnostic performance when used in a step-wise fashion. As part of the ongoing endeavor to create a common diagnostic chart for the precise and cost-effective use of biomarkers in neurocognitive diseases with neurodegenerative origin, these data gain further significance.
Additionally, by combining semiquantitative [18F]-FDG-PET and CSF data, we were able to identify precise topographic correlations between metabolic values and CSF proteins that indicated distinct underlying disease processes. These findings add to the knowledge regarding the distribution of hypometabolism linked to neuronal loss, which is distinct from metabolic changes reflecting synaptic or axonal injury, and provide an indirect insight of the pathological processes taking place at various times in different parts of the brain.
These results will be expanded into bigger cohorts in future research, which will also integrate additional newly discovered synaptopathy-expressing proteins for diagnostic and prognostic purposes
FDG PET Unveils the Course of Paraneoplastic Cerebellar Degeneration: A Semiquantitative Analysis
No full textIn paraneoplastic cerebellar degeneration (PCD), the standard diagnostic workup might be inconclusive, especially in seronegative subtypes. Brain 18F-FDG PET is an accurate supportive diagnostic tool in immune-mediated disorders, but findings in PCD are controversial. Semiquantitative analysis of 18F-FDG PET can meaningfully assist visual assessment in different neurological conditions and has been mainly applied to disclose regional hypometabolism. We describe a seronegative PCD associated with small cell lung cancer in which 18F-FDG PET semiquantitative analysis accurately disclosed the longitudinal pathological changes of brain metabolism occurring in the acute and posttreatment remission stages and paralleling clinical impairment and response to treatment
Distributed misbehavior monitors for socially organized autonomous systems
No full textIn systems in which many heterogeneous agents operate autonomously, with competing goals and without a centralized planner or global information repository, safety and performance can only be guaranteed by "social" rules imposed on the behavior of individual agents. Social laws are structured in a way that they can be verified just by using local information made available to an agent by a small number of its neighbors. Automobile mobility with traffic rules and logistics robots in warehouses are canonical examples of such "regulated autonomy", but many other fairly-competing autonomous systems are to be expected shortly. In these systems, detecting whether an agent is not abiding by the rules is crucial for raising an alert and taking appropriate countermeasures. However, the limited visibility due to the local nature of the information makes the problem of misbehavior detection hard for any single agent, and only an exchange of information between agents can provide sufficient clues to arrive at a decision. This paper attacks the misbehavior detection problem for a class of socially organized autonomous systems, where the behavior of agents depends on the presence or absence of other neighbors. We propose a solution involving a "local monitor", which runs on each agent and includes a hybrid observer and a set-valued consensus node. Based on whatever visibility is available, it reconstructs a set-valued occupancy estimate of nearby regions and combines it with communicating neighbors to reach a shared view and a mismatch discovery. We provide a formal framework for describing social rules that unify many different applications and a tool to generate code automatically for local monitors. The technique is demonstrated in various systems, including self-driving cars, autonomous forklifts, and distributed power plants
Serum neurofilament light chain rate of change in Alzheimer's disease: potentials applications and notes of caution
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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
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