186,260 research outputs found
In situ monitoring of atomic layer epitaxy via optical ellipsometry
No full textAbstract We report on the use of time-resolved optical ellipsometry to monitor the deposition of single atomic layers with subatomic sensitivity. Ruddlesden–Popper thin films of SrO(SrTiO3)n=4 were grown by means of metalorganic aerosol deposition in the atomic layer epitaxy mode on SrTiO3(1 0 0), LSAT(1 0 0) and DyScO3(1 1 0) substrates. The measured time dependences of ellipsometric angles, Δ(t) and Ψ(t), were described by using a simple optical model, considering the sequence of atomic layers SrO and TiO2 with corresponding bulk refractive indices. As a result, valuable online information on the atomic layer epitaxy process was obtained. Ex situ characterization techniques, i.e. transmission electron microscopy, x-ray diffraction and x-ray reflectometry verify the crystal structure and confirm the predictions of optical ellipsometry.EU FP 7 Project ‘IFOX’Swiss National Foundatio
Antiproliferative and cytotoxic activities of C-Geranylated flavonoids from Paulownia tomentosa Steud. Fruit
No full textPrenylated or geranylated flavonoids have been studied for their promising antiproliferative and cytotoxic activities. Twelve natural geranylated flavonoids (1–12) were isolated from the fruit of Paulownia tomentosa Steud. Their structures were elucidated using UV and IR spectroscopy, mass spectrometry, and 1D and 2D NMR spectroscopy. The absolute configurations were determined using NMR and circular dichroism. Seven of the compounds were characterized as new geranylated derivatives isolated from a natural source for the first time, namely 3′-O-methyl-5′-hydroxyisodiplacone (3), paulodiplacone A (5), tomentone II (6), tomentone B (7), tomentodiplacone P (8), paulodiplacone B (9), and tomentoflavone A (12). After 24 h of incubation at concentrations in the range 1–30 μM, the isolated compounds were tested for their antiproliferative and cytotoxic potentials against the human monocytic leukaemia cell line THP-1, using WST-1 and LDH assays, respectively. Almost all of the test compounds induced a concentration-dependent reduction in the metabolic activity of THP-1 cells and a concentration-dependent reduction in the cell viability. Diplacone (1) was the most potent antiproliferative and cytotoxic agent (IC50 9.31 ± 0.72 μM, LC50 18.01 ± 1.19 μM). 3′-O-Methyl-5′-hydroxydiplacone (2) showed relatively strong antiproliferative effect (IC50 12.61 ± 0.90 μM) and weaker cytotoxic activity (LC50 > 30 μM), indicating that it may serve as a potential lead compound for further testing. The structure-activity relationship for the 12 isolated compounds is discussed
Mapping regional forest management for the continental United States
No full textThe source stored in this figshare repository represents the
python and R scripts to map regional forest management for the continental
United States at 250 meter resolution. The management maps are produced using
Breaks For Additive Seasonal Trends (BFAST) and Random Forest (RF) models
described by Marsik et al (in submission to Nature Scientific Data) and
available for download at: https://doi.pangaea.de/10.1594/PANGAEA.880304.
The submitted manuscript contains descriptions of the BFAST analysis, and RF
model, covariates and covariate sources.
These data and the code represent the methods and algorithms
used to produce the forest management maps and probability datasets for the
Southeastern and Pacific Northwest regions of the United States.</p
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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
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
Dr. Edward P. Wimberly, ITC, July 2011
No full textThis video is a conversation with Dr. Edward P. Wimberly. Dr. Wimberly talks about his book, "No Shame in Wesley's Gospel: A Twenty-First Century Pastoral Gospel". Brad Ost, AUC Woodruff Library, is the interviewer
Author Rights and Scholarly Publishing
Full text linkOriginally posted at
http://blog.library.gsu.edu/2014/10/24/author-rights-and-scholarly-publishing/</p
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