170,663 research outputs found
Street Democracy
No full textNo visitor to Mexico can fail to recognize the omnipresence of street vendors, selling products ranging from fruits and vegetables to prepared food and clothes. The vendors compose a large part of the informal economy, which altogether represents at least 30 percent of Mexico’s economically active population. Neither taxed nor monitored by the government, the informal sector is the fastest growing economic sector in the world. In Street Democracy Sandra C. Mendiola García explores the political lives and economic significance of this otherwise overlooked population, focusing on the radical street vendors during the 1970s and 1980s in Puebla, Mexico’s fourth-largest city. She shows how the Popular Union of Street Vendors challenged the ruling party’s ability to control unions and local authorities’ power to regulate the use of public space. Since vendors could not strike or stop production like workers in the formal economy, they devised innovative and alternative strategies to protect their right to make a living in public spaces. By examining the political activism and historical relationship of street vendors to the ruling Institutional Revolutionary Party (PRI), Mendiola García offers insights into grassroots organizing, the Mexican Dirty War, and the politics of urban renewal, issues that remain at the core of street vendors’ experience even today
Growth of KNbO<sub>3</sub> thin films on MgO by pulsed laser deposition
No full textCrystalline and stoichiometric KNbO3 thin films have been grown on (100) oriented MgO substrates by pulsed laser deposition technique. Electron microprobe analysis and Rutherford backscattering spectroscopy of the films show a progressive loss of K with increasing substrate-target distance. To compensate for this K loss the ceramic KNbO3 targets were enriched with K2CO3 powder, pressed at room temperature and sintered at 650°C. For a substrate-target distance of 6 cm, targets with [K]/[Nbl molar ratio = 2.85 yield stoichiometric KNbO3 films. A partial oxygen pressure of 2 x mbar was optimum for growing transparent films. Films grown between 650 and 700°C show the KNbO3 crystalline phase with its (110) axis preferentially oriented perpendicular to the surface of the substrate. At these temperatures KNbO3 diffusion into the MgO substrate is observed. Films grown from KNbO3 single crystal targets only contain a Mg4Nb2O9 crystalline layer
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full textOphthalmology. 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
No full textWe 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
Pulsed laser deposition of KNbO<sub>3</sub> thin films
No full textThe laser ablation of stationary KNbO3 single crystal targets induces a Nb enrichment of the target surface. In rotated targets this effect is observed only in those areas irradiated with low laser fluence. The composition of the plasma formed close to the target surface is congruent with the target composition; however, at further distances K-deficient films are formed due to the preferential backscattering of K in the plasma. This loss may be compensated for by using K-rich ceramic targets. Best results so far have been obtained with [K]/[Nb] = 2.85 target composition, and crystalline KNbO3 films are formed when heating the substrates to 650 °C. Films formed on (100)MgO single crystals are usually single phase and oriented with the (110) film plane parallel to the (100) substrate surface. (100)NbO may coexist with KNbO3 on (100)MgO. At substrate temperatures higher than 650 °C, niobium diffuses into MgO forming Mg4Nb2O9 and NbO, leading to K evaporation from the film. Films formed on (001) alpha-Al2O3 (sapphire) show the coexistence of (111), (110), and (001) orientations of KNbO3, and the presence of NbO2 is also observed. KNbO3 films deposited on (001)LiNbO3 crystallize with the (111) plane of the film parallel to the substrate surface. For the latter two substrates the Nb diffusion into the substrate is lower than in MgO and consequently the K concentration retained in the film is comparatively larger
La explicación histórica: el papel de las narrativas. Apuntes sobre “Narración y conocimiento” de Arthur C. Danto / The Historical Explanation: The Part Played by Narratives. Notes on Narration and Knowledge in Arthur C. Danto
No full textEl autor sostiene que Arthur C. Danto, al tratar de fundamentar a la historia como una ciencia positiva, una ciencia que explica y que por fuerza tiene que poder probarse objetivamente, ofreció elementos que hacen posible un conocimiento de algo episódico y no del cambio. Para mostrar esto se concentra en su concepción de las explicaciones históricas, poniendo especial atención en cómo aparece la expresión del cambio en ellas.Palabras clave: narrativa, Danto, filosofía, historia, ciencia. The author proposes that while Arthur C. Danto tried to found history as a positive science, one that explains and that necessarily has to be proven objectively, he offered elements that make the knowledge of episodes possible but not of change itself. In order to show this, the author considers Danto’s conception of historic explanations, paying special attention in how the expression of change appears in them.Keywords: narrative, Danto, philosophy, history, science. Artículo recibido: 8-2-2016Artículo aceptado: 15-10-201
Dialipsis villahermosae Humala & Selfa n. sp (Hymenoptera: Ichneumonidae), the second European species of the genus, with biological notes and a key of Palaearctic species
No full textThe small genus Dialipsis Ferster 1869 (Hymenoptera: Ichneumonidae) includes two known species, of which one is common in Central and Northern Europe. Here we describe the male and female of a new species, Dialipsis villahermosae Humala & Selfa, which was reared from mushrooms collected in Eastern Spain. The host fungus gnat, Mycetophila blanda Winnertz, is a new record for the whole genus, while the rate of parasitism seems very low. Based on environmental data of the collection localities and data available for other two species it is suggested that Dialipsis species occur preferably in cool temperatures habitats. A key of identification of the two known Palaearctic species is provided. D. villahermosae n. sp. differs from D. exilis Ferster 1871 in the morphology of the first tergite, referred to the presence of dorsal keels and angle between petiole and postpetiole, and in the convexity of temples
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe 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
Antimicrobial activity of organotin(IV) complexes with the ligand benzil bis(benzoylhydrazone) and 4,4'-bipyridyl as coligand
No full textSeveral methyltin(IV) and butyltin(IV) complexes with the ligand benzil bis(benzoylhydrazone) and 4,4'-bipyridyl as coligand were synthesised and characterized by elemental analysis and by IR. (1)H, (13)C and (119)Sn NMR spectroscopies. Some of them were also analyzed using single crystal X-ray diffraction. The title compounds were evaluated for their in vitro antimicrobial properties. All buthyltin complexes showed significant inhibition of Gram positive bacteria, resulting Bacillus subtilis, Sarcina lutea and both methicillin-susceptible and methicillin-resistant Staphylococcus epidermidis the most sensitive strains. Furthermore, they were able to inhibit the growth of Gram negative bacteria, especially Proteus vulgaris, whereas no activity was exhibited against fungi. All methyltin complexes were devoid of antimicrobial properties
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