1,721,141 research outputs found
Cambio demográfico y desigualdad social en Venezuela al inicio del tercer milenio
No full textCambio demógrafico y desigualdad social. - Urbanización y migración interna. - Factores demográficos vs. efectos ambientales. - Aspectos éticos de la población venezolana. - Estudios de población en salud. - Estudios de población y enfoque de género. - Aspectos laborales de la población venezolana. - Estructuras de los hogares y familias. - Fecundidad y salud sexual y reproductiv
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
Trimethoprim Removal from Aqueous Solutions via Volcanic Ash-Soil Adsorption: Process Modeling and Optimization
No full textAntibiotic contamination of water sources is a significant environmental and public health concern. This contamination is classified among the most dangerous types of pollution currently because of their harmful effects. Therefore, it is essential to identify effective and environmentally friendly ways to deal with those dangerous compounds. Within this context, this work looked into whether soils made from volcanic ash could be used as cost-effective adsorbents to remove the antibiotic trimethoprim (TRM) from aqueous solutions. To examine the impacts of the main operating parameters on TRM removal, which are the initial antibiotic concentration (C), contact time (t), stirring speed (S), and solid-to-liquid ratio (R), a Central Composite Design (CCD) based on the Response Surface Methodology (RSM) was employed. Full quadratic polynomial models were used to correlate the experimental data, allowing for the estimation of each factor’s influence. With a predicted removal efficiency of 77.59%, the removal process optimization yielded the following set of optimal conditions: C = 4.5 mg/L, t = 45.5 min, S = 747 rpm, and R = 0.04 g/mL. Experiments conducted under predicted ideal conditions supported both the result and the previously developed model’s capacity for prediction. Additionally, the adsorption mechanism was also proposed based on the characterization of the adsorbent before and after the treatment. The study’s findings provide the possibility of using soils formed from volcanic ash as a cost-effective adsorbent material for the removal of TRM and likely other similar pollutants from contaminated waters
Effectiveness of different photoadvanced oxidationdegradation processes (AOPs) on the abatement of mepanipyrim and its transformation products in water
No full textThis study aims to present the effectiveness of different advanced oxidation processes (AOPs) as photolysis (UV mercury arc and Xe-arc), ozone, ozone/Hg-UV, and photocatalysis (suspended and immobilized TiO2) for the degradation of the fungicide mepanipyrim in aqueous solutions. A well-known commercial product Pilkington ActiveTM Blue glass has been tested as immobilized TiO2 system. Experiments were performed in batch mode at laboratory scale and results were compared in terms of disappearance kinetics. Transformation products (TPs) were identified by Surveyor LC system coupled to a hybrid LTQ-FTICR (7-Tesla) mass spectrometer (MS). Simple mechanisms of degradation for different AOPs were proposed. New by-products formed during the degradation processes were identified. Since primarily hydroxy derivatives were identified in aqueous suspensions, the mechanism of degradation was probably based on hydroxyl radical attack. The greatest difference in the quality of transformation products was observed between the heterogeneous photocatalysis using suspended TiO2 and Pilkington ActiveTM Blue glass system. The inhibition percentage of bioluminescence from Vibro fischeri — as a toxicity parameter—increased during the irradiation time due to the residual concentration of the parent compound and transformation products generated.
Discover the world's researc
Las migraciones internas en Venezuela. Especificidades territoriales de los movimientos migratorios del período reciente
No full textEn este estudio se analizan las migraciones internas en Venezuela a partir de la explo tación de los microdatos correspondientes a los Censos de 1990 y 2001. Dicho análisis se
concibe dentro de dos ejes de segmentación territorial, que responden a distintos niveles
de desagregación geográfica. El primero de ellos se ubica en un nivel interestatal, desde
el que se examinan las tasas de inmigración, emigración y migración neta para medir
tanto la intensidad como el patrón espacial de los movimientos de corta data. Además,
se identifican los cambios de la dinámica migratoria en el período reciente comparan do los indicadores de la movilidad quinquenal para ambos censos (tasas de inmigración
y emigración). En este sentido, se construye una tipología de la movilidad estatal que
sistematiza las transformaciones de los balances migratorios de las entidades federales
ocurridas en el tiempo
Seizure and delirium caused by ketamine's intoxication mimicking limbic encephalitis; a case report
No full textDropped head as presenting sign of acute motor and sensory neuropathy with reversible conduction failure
No full text- …
