384 research outputs found

    Visual consciousness tracked with direct intracranial recording from early visual cortex in humans

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    A fundamental question in cognitive neuroscience is how neuronal representations are related to conscious experience.
Two key questions are: where in the brain such representations are located, and at what point in time they correlate with conscious experience. In line with this issue, a hotly debated question is whether primary visual cortex (V1) contributes to visual consciousness, or whether this depends only on higher-order cortices. Here we investigated this issue by recording directly from early visual cortex in two neurosurgical patients undergoing epilepsy monitoring with intracranial electrocorticogram (ECoG) electrodes that covered early visual cortices, including the dorsal and ventral banks of the calcarine sulcus. We used Continuous Flash Suppression (CFS)to investigate the time course of when ‘invisible’ stimuli broke interocular suppression. Participants were asked to watch faces presented under CFS, to push a button when they started to see any part of the face, and then to indicate its spatial location. This occurred over several seconds. During the task performance we recorded intracranial ECoG at high spatiotemporal resolution from all contacts in parallel. We used multivariate decoding techniques and found that the location of the invisible face stimulus became decodable from neuronal activity 1.8 sec before the subject’s button press. Counter-intuitively, the same cortical sites from which we were able to decode this predictive signal showed a decrease in activity immediately prior to the transition from invisibility to visibility. Furthermore, we observed an increase in coherence among widely separated electrodes during the invisible epoch, which collapsed to a focal ensemble when the stimulus became visible. These results suggest that diffuse coherent representation is insufficient for visual awareness and that locally specialized patterns of activation may be key to consciousness. Our findings are consistent with one recently proposed framework for understanding consciousness utilizing information integration theory (Tononi, 2008)

    Green tea inhibited the elimination of nephro-cardiovascular toxins and deteriorated the renal function in rats with renal failure

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    Chronic kidney disease (CKD) is a major health problem worldwide. Indoxyl sulfate (IS) and p-cresyl sulfate (PCS) are highly protein-bound nephro-cardiovascular toxins, which are not efficiently removed through hemodialysis. The renal excretions of IS and PCS were mediated by organic anion transporters (OATs) such as OAT1 and OAT3. Green tea (GT) is a popular beverage containing plenty of catechins. Previous pharmacokinetic studies of teas have shown that the major molecules present in the bloodstream are the glucuronides/sulfates of tea catechins, which are putative substrates of OATs. Here we demonstrated that GT ingestion significantly elevated the systemic exposures of endogenous IS and PCS in rats with chronic renal failure (CRF). More importantly, GT also significantly increased the levels of serum creatinine (Cr) and blood urea nitrogen (BUN) in CRF rats. Mechanism studies indicated that the serum metabolites of GT (GTM) inhibited the uptake transporting functions of OAT1 and OAT3. In conclusion, GT inhibited the elimination of nephro-cardiovascular toxins such as IS and PCS, and deteriorated the renal function in CRF rats

    Implementation of the Louisville COVID-19 Surveillance Protocol: Experiences from the University of Louisville Center of Excellence for Research in Infectious Diseases [CERID]

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    The lack of available testing for SARS-CoV-2 has been one of the primary challenges in the development and implementation of a comprehensive approach to infection prevention and transmission in the United States (US). In response to the need for increased testing capacities and capabilities, the University of Louisville (UofL) Division of Infectious Diseases, Center of Excellence for Research in Infectious Diseases (CERID) initiated the Louisville Coronavirus Surveillance Program, a comprehensive approach to surveillance and testing of patients and healthcare workers. The first specimens were accepted on March 12, 2020 and parallel testing was done using a high-capacity testing process and the Division of Infectious Diseases CLIA-certified laboratory to ensure concordant results. Steps in the testing process began with validation of the testing methods and included database development, acceptance of specimens, tracking and cataloging the specimens, testing, and reporting of results. Quality metrics were developed and used to prevent error and facilitate rapid reporting. Between March 12, 2020 and April 30, 2020, more than 5500 tests were performed identifying more than 850 patients and healthcare workers infected with COVID-19 in the Louisville, Kentucky area. Although the process used high-capacity robotics for testing procedures, the methods described here are applicable to settings employing a variety of laboratory testing methods

    Efficacy of once-daily extended-release topiramate (USL255): A subgroup analysis based on the level of treatment resistance

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    AbstractResults from a previously conducted global phase III study (PREVAIL; NCT01142193) demonstrate the safety and efficacy of once-daily USL255, Qudexy™ XR (topiramate) extended-release capsules, as adjunctive treatment of drug-resistant partial-onset seizures (POSs). In this study, we report a post hoc analysis of PREVAIL data according to patient level of treatment resistance (based upon the number of concomitant antiepileptic drugs [AEDs] and lifetime AEDs) at baseline, with patients defined as either having “highly” drug-resistant seizures (≥2 concurrent AEDs and ≥4 lifetime AEDs) or having “less” drug-resistant seizures (1 concurrent AED or <4 lifetime AEDs) at baseline. For each subgroup, median percent reduction in POS frequency (primary endpoint), responder rate, Clinical Global Impression of Change (CGI-C), and Quality of Life in Epilepsy — Problems (QOLIE-31-P) survey were assessed. Of 249 PREVAIL patients, 115 were classified as having highly drug-resistant seizures (USL255: n=52, placebo: n=63), and 134 were classified as having less drug-resistant seizures (USL255: n=72, placebo: n=62) at baseline. For the primary endpoint, USL255 resulted in significantly better seizure outcomes compared with placebo regardless of drug-resistant status (P=.004 and P=.040 for “highly” and “less”, respectively). Responder rate was also significantly improved in patients with highly drug-resistant group (P=.023). The CGI-C scores indicated significant improvement in both subgroups (P=.003 and P=.013 for “highly” and “less”, respectively). On the QOLIE-31-P, a significant improvement on the seizure worry subscale for the group with less drug-resistant seizures was noted in USL255-treated patients compared with placebo-treated patients (P=.003); the overall score and all other subscales were not significantly different for both subgroups. We conclude that USL255 led to significant improvements across multiple outcomes compared with placebo, including in those classified as having highly drug-resistant seizures to prior treatment, making it a valuable treatment option for patients with epilepsy

    Mathematical modelling for Singapore primary classrooms : from a teacher’s lens

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    Limited Singapore research indicated a lack of exposure of modelling tasks at primary levels. Teacher reflection is used as a tool in design research cycles exploring the potentials of modelling tasks in a Singapore primary five classroom. Findings reveal that the teacher identified three potentials of a modelling task on children&rsquo;s mathematisation process: the task provided a platform for children to (a)&nbsp;identify variables and form relationships between them, (b) relate school-based&nbsp;math learning to real-world experiences, and (c) justify their mathematical models. Implications on the promotion of modelling tasks at primary schools as well as teacher education are drawn

    Accurate, rapid and high-throughput detection of strain-specific polymorphisms in Bacillus anthracis and Yersinia pestis by next-generation sequencing

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    Background: In the event of biocrimes or infectious disease outbreaks, high-resolution genetic characterization for identifying the agent and attributing it to a specific source can be crucial for an effective response. Until recently, in-depth genetic characterization required expensive and time-consuming Sanger sequencing of a few strains, followed by genotyping of a small number of marker loci in a panel of isolates at or by gel-based approaches such as pulsed field gel electrophoresis, which by necessity ignores most of the genome. Next-generation, massively parallel sequencing (MPS) technology (specifically the Applied Biosystems sequencing by oligonucleotide ligation and detection (SOLiD™) system) is a powerful investigative tool for rapid, cost-effective and parallel microbial whole-genome characterization. Results: To demonstrate the utility of MPS for whole-genome typing of monomorphic pathogens, four Bacillus anthracis and four Yersinia pestis strains were sequenced in parallel. Reads were aligned to complete reference genomes, and genomic variations were identified. Resequencing of the B. anthracis Ames ancestor strain detected no false-positive single-nucleotide polymorphisms (SNPs), and mapping of reads to the Sterne strain correctly identified 98% of the 133 SNPs that are not clustered or associated with repeats. Three geographically distinct B. anthracis strains from the A branch lineage were found to have between 352 and 471 SNPs each, relative to the Ames genome, and one strain harbored a genomic amplification. Sequencing of four Y. pestis strains from the Orientalis lineage identified between 20 and 54 SNPs per strain relative to the CO92 genome, with the single Bolivian isolate having approximately twice as many SNPs as the three more closely related North American strains. Coverage plotting also revealed a common deletion in two strains and an amplification in the Bolivian strain that appear to be due to insertion element-mediated recombination events. Most private SNPs (that is, a, variant found in only one strain in this set) selected for validation by Sanger sequencing were confirmed, although rare falsepositive SNPs were associated with variable nucleotide tandem repeats. Conclusions: The high-throughput, multiplexing capability, and accuracy of this system make it suitable for rapid whole-genome typing of microbial pathogens during a forensic or epidemiological investigation. By interrogating nearly every base of the genome, rare polymorphisms can be reliably discovered, thus facilitating high-resolution strain tracking and strengthening forensic attribution

    2003 AAPP Monograph Series

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    It is significant that the African American Professors Program (AAPP) at the University of South Carolina is producing the third edition of its annual monograph series at this time-the fifth anniversary of AAPP. The program graciously accepts the challenge of putting into place a requirement for the scholars to produce quality research papers worthy of publication. This provides widespread visibility for them and enhances their curriculum vitae concurrently. Scholars who have contributed manuscripts for this monograph are to be commended for adding this additional responsibility to their academic workload. Writing across disciplines adds to the intellectual diversity of these papers. From neophytes, relatively speaking, to an array of very experienced individuals, the chapters have been researched and comprehensively written. Founded in 1997 through the Department of Educational Leadership and Policies in the College of Education, AAPP was designed to address the underrepresentation of African American professors on college and university campuses. Its mission is to expand the pool of these professors in critical academic and research areas. Sponsored by the University of South Carolina, the W. K. Kellogg Foundation, and the South Carolina General Assembly, the program recruits students with bachelor\u27s, master\u27s, and doctoral degrees for disciplines in which African Americans currently are underrepresented. An important component of the program is the mentoring experience that is provided. Each student is assigned to a mentor/professor who guides the student through a selected academic program and provides various learning experiences. When possible, the mentor serves as chair of the student\u27s doctoral committee. The mentor also provides opportunities for the student to team teach, conduct research, and co-author publications. Students have the advantage of attending committee, faculty, and professional meetings, as well as engaging in a range of activities that characterize professional life in academia. Scholars enrolled in the program also are involved in programmatic and institutional workshops, independent research, and program development. The continuation of this monograph series is seen as responding to a window of opportunity to be sensitive to an academic expectation of graduates as they pursue career placement and, at the same time, one that allows for the dissemination of AAPP products to a broader community. The importance of this monograph series has been voiced by one of our 2002 AAPP graduates, Dr. Shundelle LaTjuan Dogan, a recent Harvard Administrative Fellow at Harvard University and now Program Officer for the Southern Education Foundation, Atlanta, Georgia. Dr. Dogan wrote: One thing in particular that I want to thank you for is having the African American Professors Program scholars publish articles for the monograph. I have to admit that writing the articles seemed like extra work at the time. However, in my recent interview process, organizations have asked me for samples of my writing. Including an article from a published monograph helped to make my portfolio much more impressive. You were right on target in having us do the monograph series. We hope that you will read this monograph of the African American Professors Program with enthusiasm or enlightenment. John McFadden, Ph.D. The Benjamin Elijah Mays Professor Director, African American Professors Program University of South Carolinahttps://scholarcommons.sc.edu/mcfadden_monographs/1006/thumbnail.jp

    “Citizen Journalism” in the Syrian Uprising: Problematizing Western Narratives in a Local Context

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    This article analyzes the term ‘citizen journalism’ against the backdrop of the Arab uprisings in order to show how it overlooks the local context of digital media practices. The first part examines videos emanating from Syria to illustrate how they blur the lines between acts of witnessing, reporting, and lobbying, as well as between professional and amateur productions, and civic and violent intentions. The second part highlights the genealogies of citizenship and journalism in an Arab context and cautions against assumptions about their universality. The article argues that the oscillation of Western narratives between hopes about digital media's role in democratization in the Arab World and fears about their use in terrorism circumscribe the theorization of digital media practices
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