169,799 research outputs found

    Synthesis of (+)-Pancratistatins via Catalytic Desymmetrization of Benzene

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    A concise synthesis of (+)-pancratistatin and (+)-7-deoxypancratistatin from benzene using an enantioselective, dearomative tarboarnination strategy has been achieved. This approach, in combination with the judicious choice of subsequent olefin-type difunctionalization reactions, permits rapid and controlled access to a hexasubstituted core. Finally, minimal use of intermediary steps as well as direct, late stage C-7 hydroxylation provides both natural products in six and seven operations

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    Mitomycin C in highly myopic eyes - Author reply

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    Ophthalmology. 2005 Feb;112(2):208-18; discussion 219. Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes. Gambato C, Ghirlando A, Moretto E, Busato F, Midena E. SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy. Abstract PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes. DESIGN: Prospective, double-masked, randomized clinical trial. PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia. METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months). MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH. RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively). CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK. Comment in Ophthalmology. 2006 Feb;113(2):357; author reply 357-8

    Dispelling the Myths Behind First-author Citation Counts

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    We 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

    A Multi-Language Comparison of Influences on Author Verification using Character N-Grams

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    We create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc

    A 0.12mm<sup>2</sup> Wien-Bridge Temperature Sensor with 0.1°C (3σ) Inaccuracy from -40°C to 180°C

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    Resistor-based temperature sensors can achieve much higher resolution and energy efficiency than conventional BJT-based sensors [1], but they typically occupy more area (&gt; 0.25 mm 2 ) and have lower operating temperatures (le 125 {circ} {C}) [2]-[4]. This work describes a 0.12mm 2 resistor-based sensor that uses a Wien-bridge (WB) filter to achieve 0.1 {circ} {C} (3 sigma) inaccuracy from - 40 {circ} {C} to 180 {circ} {C}. Compared to a state-of-the-art WB sensor [4], it occupies 6 × less area and achieves comparable relative accuracy over a 76% wider operating range. Session 10.3 Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic

    A ±25A Versatile Shunt-Based Current Sensor with 10kHz Bandwidth and ±0.25% Gain Error from -40°C to 85°C Using 2-Current Calibration

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    Accurate current sensing is critical in many industrial applications, such as battery management and motor control. Precise shunt-based current sensors have been reported with gain errors of less than 1% over the industrial temperature range (-40°C to 85°C) [1]–[4]. However, since they are intended for coulomb counting, their bandwidth is limited to a few tens of Hz, making them unsuitable for battery impedance or motor-current sensing. This paper presents a current sensor with a wide (10kHz) bandwidth and a tunable temperature compensation scheme (TCS), which allows it to be flexibly used with different types of shunts while maintaining high accuracy. A low-cost room-temperature calibration scheme is proposed to optimize gain flatness over temperature by exploiting the shunt's self-heating at large currents. Over the industrial temperature range and a ±25A current range, it achieves state-of-the-art gain error (±0.25%) with both low-cost PCB and stable metal-alloy shunts.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic

    Climate change action as a project of identity: Eight meta-analyses

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    Identity can improve our understanding of personal climate action, particularly when climate action becomes an expression of a person's self. However, it is unclear which kind of self or identity is most relevant. Building on a comprehensive series of eight meta-analyses (using data from 188 published articles, N = 414,282 participants) this research systematically compares how strongly climate-friendly intentions and behaviors are associated with place identity, personal connectedness to nature, environmental self-identity (i.e., personal self-definition as a pro-environmentally acting person), and social identity (i.e., identification with social groups). Results suggest robust, medium-sized to strong links of both pro-environmental intentions and behaviors to people's nature connectedness (r = 0.44/0.52), environmental self-identity (r = 0.62/0.56), and identification with groups considered to support climate-friendly behavior (r = 0.48/0.51), but markedly weaker effects for identification with groups which are unrelated to environmental topics (r = 0.30/0.15) and for place identity (r = 0.18/0.32). Implications for policy interventions and psychological theory are discussed

    An Article About Albertus C. Van Raalte, Author Unknown, Except for Parts Taken from an Article by Anna C. Post

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    An article about Albertus C. Van Raalte, author unknown, except for parts taken from an article by Anna C. Post. The author knew first generation persons in the Holland settlement and therefore, the article has some value.https://digitalcommons.hope.edu/vrp_1890s/1012/thumbnail.jp

    Donations to renewable energy projects: The role of social norms and donor anonymity

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    This paper shows that interventions based on social norms and on increasing the visibility of people's decisions to others (“decision observability”) present promising pathways of generating public support for renewable energy development. In a laboratory experiment (n = 300), we show that social norms and decision observability increase support for renewable energy, even at a financial cost to oneself: When exposed to pro-environmental social norms, participants donated 35% more money to an existing renewable energy initiative than participants in the control condition (Cohen's d = 0.35). Participants whose decisions were observable to others donated 23% more compared to control (d = 0.23). And participants exposed to both treatments (their decisions being observed by others and learning about norms) donated 69% more compared to control (d = 0.67). In addition, our treatments had a positive effect on participants' post-decisional emotions of happiness and pride, which partly alleviates existing concerns about possible adverse side-effect of social influence interventions. Suggestions for policy makers and for future research in this area are presented
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