1,721,165 research outputs found
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
Investigation of gene-gene interactions in cardiac traits and serum fatty acid levels in the LURIC Health Study
No full textEpistasis analysis elucidates the effects of gene-gene interactions (G×G) between multiple loci for complex traits. However, the large computational demands and the high multiple testing burden impede their discoveries. Here, we illustrate the utilization of two methods, main effect filtering based on individual GWAS results and biological knowledge-based modeling through Biofilter software, to reduce the number of interactions tested among single nucleotide polymorphisms (SNPs) for 15 cardiac-related traits and 14 fatty acids. We performed interaction analyses using the two filtering methods, adjusting for age, sex, body mass index (BMI), waist-hip ratio, and the first three principal components from genetic data, among 2,824 samples from the Ludwigshafen Risk and Cardiovascular (LURIC) Health Study. Using Biofilter, one interaction nearly met Bonferroni significance: an interaction between rs7735781 in XRCC4 and rs10804247 in XRCC5 was identified for venous thrombosis with a Bonferroni-adjusted likelihood ratio test (LRT) p: 0.0627. A total of 57 interactions were identified from main effect filtering for the cardiac traits G×G (10) and fatty acids G×G (47) at Bonferroni-adjusted LRT p −5 was associated with 9-trans 12-trans octadecanoic acid, an omega-6 trans fatty acid. The model inflation factor for the interactions under different filtering methods was evaluated from the standard median and the linear regression approach. Here, we applied filtering approaches to identify numerous genetic interactions related to cardiac-related outcomes as potential targets for therapy. The approaches described offer ways to detect epistasis in the complex traits and to improve precision medicine capability
Association of obstructive sleep apnea and opioids use on adverse health outcomes: A population study of health administrative data
Full text linkRATIONALE: Despite the high prevalence of obstructive sleep apnea (OSA) and concurrent use of opioid therapy, no large-scale population studies have investigated whether opioid use and pre-existing OSA may interact synergistically to increase the risk of adverse health consequences. To address this knowledge gap, we conducted a retrospective cohort study using provincial health administrative data to evaluate whether the combined presence of opioid use and OSA increases the risk of adverse health consequences, such as mortality, hospitalizations, and emergency department (ED) visits; and if it does, whether this co-occurrence has synergistic clinical relevance. METHODS: We included all adults who underwent a diagnostic sleep study in Ontario, Canada, between 2013 and 2016. Individuals were considered exposed to opioids if they filled a prescription that overlapped with the date of their sleep study (Opioid+). Individuals with at least a 50% probability of having a diagnosis of moderate to severe OSA (OSA+) were identified using a previously externally validated case-ascertainment model. The primary outcome was all-cause mortality; secondary outcomes were all-cause or ischemic heart disease hospitalizations, all-cause ED visits, and motor vehicle collisions (MVC) requiring hospital or ED visit. We used multivariable Cox regression models to compare hazards between four mutually exclusive groups: (1) Opioid+ OSA+; (2) Opioid+ OSA-; (3) Opioid- OSA+, and (4) OSA- Opioid- (reference for comparison). Relative excess risks due to interaction (RERI) were calculated to test for additive interaction. RESULTS: Of 300,663 adults who underwent a sleep study, 15,713 (5.2%) were considered as Opioid+ and 128,351 (42.7%) as OSA+. Over a median of two years, 6,223 (2.1%) died from any cause. Regardless of OSA status, opioid use at the date of the sleep study was associated with an increased hazard for all-cause mortality with the greatest hazard associated with Opioid+ OSA- (adjusted hazard ratio [aHR]: 1.75, 95% CI 1.57–1.94), but not Opioid+ OSA+ (aHR: 1.14, 95% CI 1.02–1.27) as hypothesized. Regardless of OSA status, opioid use at the date of the sleep study was associated with an increased hazard for all secondary outcomes. Opioid+ OSA+ was associated with the greatest hazards of all-cause hospitalizations (aHR 1.55, 95% CI 1.49–1.61) and MVC (aHR of 1.39; 95% CI 1.09–1.77); however, no statistically significant synergistic effects were observed. CONCLUSIONS: Adults referred for sleep disorder assessment who used opioids had a significantly increased hazard of adverse health outcomes than those who did not, regardless of whether they had a high probability of moderate to severe OSA. The use of opioids and OSA was associated with the greatest hazard of all-cause hospitalizations and MVC requiring hospital or ED visit. The interaction of opioids and OSA did not confer a synergistic risk for poor outcomes
Fabrication and characterisation of high efficiency inverted P3HT:PCBM polymer solar cells.
Full text linkAmong many photovoltaic (PV) technologies polymer-fullerene based inverted bulk heterojunction (BHJ) solar cells have drawn lot attention in recent years due to low cost fabrication over a large area by using simple solution-processed methods. This thesis presents a study of inverted organic solar cells (OSCs) on indium tin oxide (ITO) coated glasses and metal substrates using spin coating technique. Zinc oxide (ZnO) and poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) were used as the electron transport layer (ETL) and hole transport layer (HTL) respectively. Poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methylester (P3HT:PCBM) was used as an active layer. The ZnO layers deposited using nanoparticles (NPs) and sol-gel route at a temperature of 150 °C. The poor wettability of aqueous PEDOT:PSS on the hydrophobic P3HT:PCBM layer was improved with the addition of surfactant Triton X-100. The P3HT:PCBM photoactive layer was optimised in terms of solvents, concentrations and layer thickness. However, the thickness of the active layer in BHJ devices need to be very thin (-200 nm) which causes poor light absorption and low carrier mobilities. Therefore, it is important to introduce new approaches to enhance the photon absorption efficiency of the active layer under the film thickness limitation. Among all the approaches plasmonic nanostructures have recently emerged as an expanding area to enhance light absorption in organic photovoltaic (OPV) devices. A low vacuum Plasma assisted physical vapour deposition (PAPVD) method was used to deposit Gold (Au) NPs thin film onto the PEDOT:PSS layer in the inverted P3HT:PCBM OSC devices. The Au NPs incorporated into the PEDOT:PSS layer and reaching the active P3HT:PCBM layer can provide a significant plasmonic broadband light absorption enhancement to the active layer. An improvement in the short circuit current density of 50-90% has been achieved compared with those OSC devices without the plasmonic light absorption enhancement. The enhanced current density is directly related to the enhancement of light absorption in the active P3HT:PCBM layer due to the creation of localized surface plasmonic resonance (LSPR) by Au NPs or nanometer-sized Au clusters. OSC devices were fabricated with various thicknesses of Au NPs films; the OSC device with -5.0 nm Au NPs film exhibited an efficiency of - 5.01% with a fill factor of -66.61%. The obtained improvement in power conversion efficiency (PCE) is mainly assigned to the noticeable increase of photocurrent and the improvement in the fill factor.Top illuminated inverted OSC devices were fabricated on metal substrates, namely: polished stainless steel (SS), titanium coated steel (Ti-S), chromium coated aluminium (Cr-Al) and polished aluminium (Al). OSC devices on metals had the simple structure of (Metal substrate/sol-gel ZnO/P3HT:PCBM/PEDOT:PSS/hcPEDOT:PSS). Good performance OSC devices were achieved on both the SS and Cr-Al substrates with an efficiency of -3.10% while no effective devices were produced on Ti-S and Al substrate. Electrical impedance spectroscopy experiments showed that the native oxide layer on top of different metal substrates causes significantly different performance in PCE for the inverted OSC devices
Fabrication of solution-processed photoactive polymer- and halide perovskite-based solar cells
No full textIn the current work, different architectures and photoactive materials have been investigated in order to fabricate low-temperature solution-processed solar cells using dip and spin coating methods.
Inverted bulk heterojunction structure has been utilised in fabrication of polymer solar cells using dip coating method. In this structure, all layers except electrodes were deposited using dip coating method, which demonstrated an excellent potential to produce large-scale area PV devices. Formulation of solutions (using different solvents) of hole transport layer, active layer, and electron transport layer play a key role in producing uniform thin films as well as compatibility with dip coating method. The best PV device achieved ~ 3.4% power conversion efficiency.
On the other hand, planar heterojunction structures have been employed to produce perovskite-based solar cells using one and two step spin coating methods (OSSCM & TSSCM). Thorough investigations of controlling the morphology of the perovskite films have been carried out using low-temperature processing methods. It was found that it is difficult to control the morphology via OSSCM without additives or using solvent engineering. Controlling the morphology of the perovskite films was achieved via TSSCM after optimizing process parameters such as the concentration of methylammonium iodide (MAI), allowed reaction time (Art), and thermal annealing.
In this work it has been established that the best morphology of the perovskite film was achieved when the 1.0 wt% MAI solution was loaded at 60 sec on top of the pre-coated PbI2 followed by thermal annealing for two hours
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Protein prediction for trait mapping in diverse populations
Full text linkGenetically regulated gene expression has helped elucidate the biological mechanisms underlying complex traits. Improved high-throughput technology allows similar interrogation of the genetically regulated proteome for understanding complex trait mechanisms. Here, we used the Trans-omics for Precision Medicine (TOPMed) Multi-omics pilot study, which comprises data from Multi-Ethnic Study of Atherosclerosis (MESA), to optimize genetic predictors of the plasma proteome for genetically regulated proteome-wide association studies (PWAS) in diverse populations. We built predictive models for protein abundances using data collected in TOPMed MESA, for which we have measured 1,305 proteins by a SOMAscan assay. We compared predictive models built via elastic net regression to models integrating posterior inclusion probabilities estimated by fine-mapping SNPs prior to elastic net. In order to investigate the transferability of predictive models across ancestries, we built protein prediction models in all four of the TOPMed MESA populations, African American (n = 183), Chinese (n = 71), European (n = 416), and Hispanic/Latino (n = 301), as well as in all populations combined. As expected, fine-mapping produced more significant protein prediction models, especially in African ancestries populations, potentially increasing opportunity for discovery. When we tested our TOPMed MESA models in the independent European INTERVAL study, fine-mapping improved cross-ancestries prediction for some proteins. Using GWAS summary statistics from the Population Architecture using Genomics and Epidemiology (PAGE) study, which comprises ∼50,000 Hispanic/Latinos, African Americans, Asians, Native Hawaiians, and Native Americans, we applied S-PrediXcan to perform PWAS for 28 complex traits. The most protein-trait associations were discovered, colocalized, and replicated in large independent GWAS using proteome prediction model training populations with similar ancestries to PAGE. At current training population sample sizes, performance between baseline and fine-mapped protein prediction models in PWAS was similar, highlighting the utility of elastic net. Our predictive models in diverse populations are publicly available for use in proteome mapping methods at https://doi.org/10.5281/zenodo.4837327
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