bluuebunny/crossref_metadata_2025_split huggingface dataset:
Revisão da paleoflora das formações Missão Velha, Crato e Romualdo, Bacia do Araripe, Nordeste do Brasil
Authors: Lima Flaviana Jorge de , Saraiva Antonio Álamo Feitosa , Sayão Juliana Manso 
Published: November 2015

A Bacia do Araripe conhecida mundialmente pelos seus fósseis apresenta excelente e bem diversificado registro de fauna e flora. Com a crescente publicação de novos achados paleobotânicos na Bacia do Araripe, apresenta-se aqui, uma síntese de toda a paleoflora descrita, até o momento, fornecendo suas informações diagnósticas. A paleoflora da bacia é abundante, variada e dominada por coníferas, contém também algumas licopsidas, pteridófitas, gnetaleanas e vegetais de afinidade desconhecida, incluindo angiospermas. As gimnospermas, angiospermas, fetos e outros componentes menos abundantes como licófitas e esfenófitas compõem a paleoflora do Araripe, sendo as gimnospermas o grupo mais abundante. De acordo com os registros, a Formação Crato (Cretáceo) possui o maior número de descrições além de ser bem mais diversificada que as Formações Missão Velha (Jurássico) e Romualdo (Cretáceo).
Rendimiento de la prueba estereoscópica Random Dot con símbolos de Lea
Authors: Álvarez González Alberto Alonso , Figueroa Olarte Luisa Fernanda 
Published: November 2015

<p>El examen de estereopsis informa sobre la calidad de la visión binocular del paciente y orienta sobre la existencia y severidad de supresiones binoculares. Objetivo: determinar la sensibilidad y especificidad de la prueba Random Dot con símbolos de Lea en niños de edad preescolar de la ciudad de Bucaramanga, entre agosto del 2009 y abril del 2010. Metodología: se aplicaron las pruebas a 349 niños. Se usó como referencia la prueba estereoscópica Randot® Preschool, confrontada con la nueva prueba Random Dot con símbolos de Lea. Dos observadores clínicos se encargaron de realizar cada uno una prueba diferente. Resultados: se observó una sensibilidad del 79,31 % y una especificidad del 80 % para la prueba Random Dot con símbolos de Lea. Valor Predictivo Positivo (VPP): 26,44 %; Valor Predictivo Negativo (VPN): 97,7 %. Conclusiones: la prueba Random Dot con símbolos de Lea no representa un valor confiable para usarla como única prueba de tamizaje visual en la detección de alteraciones de la visión binocular. La baja prevalencia (8,3 %) de la condición dentro de este estudio aumenta su VPN. Esto unido a su alta especificidad hace que la prueba sea muy eficiente cuando se trata de confirmar la probabilidad de no tener la alteración cuando otra prueba, previamente, la ha clasificado con resultados normales.</p>
Fundamentos de agudeza visual aplicados en la construcción de estímulos visuales concéntricos. Estímulo Arorradial de Guerrero (EAG)
Authors: Guerrero Vargas José Joaquín 
Published: November 2015

<p>Objetivo: comparar los parámetros fisiológicos y geométricos de los optotipos E de Snellen y C de Landolt, mediante cálculos y argumentos conceptuales, para formular el Estímulo Arorradial de Guerrero (EAG), basado en el principio angular de los primeros y la disposición concéntrica de Landolt. Metodología: se fundamentó en una revisión bibliográfica de la agudeza visual, fundamentos fisiológicos, cálculo geométrico-trigonométrico y principios anatómicos aplicables al diseño de estímulos. Dicho análisis reveló elementos comunes y diferencias del área impresa y el área perimetral de los estímulos comparados y permitió formular una matriz EAG con patrones homogéneos de estimulación foveolar. Resultados: se hallaron elementos comunes de configuración angular de los estímulos y diferencias en sus parámetros morfológicos, perimetrales y geométricos. Esto sugiere la confiabilidad de la matriz concéntrica, que estimula de forma coherente con la distribución anatómica de los fotorreceptores y, presumiblemente, brinda mayor confiabilidad de las respuestas visuales. Conclusiones: las diferencias perimetrales y geométricas halladas entre los estímulos alfanuméricos de una misma prueba sugieren que las pruebas concéntricas direccionales reúnen las condiciones de estimulación de áreas retinales homogéneas para favorecer respuestas basadas en discriminación óptica y no en legibilidad. El EAG podría constituirse en una alternativa modificada de los estímulos Landolt que, al incorporar elementos radiales que confieren direccionalidad al estímulo y distractores, permitirían estudiar cualitativamente el astigmatismo refractivo y la simulación.</p>
Frecuencia de baja visión en la población adulta mayor del distrito de San Isidro de El General, Costa Rica, segundo semestre del 2012
Authors: Mora Vargas Allan , Mata Castro Fernando , Madrigal Rodríguez Leandra , Guevara Rivera Gabriela 
Published: November 2015

<p>Actualmente la baja visión es un problema de salud pública. Resulta preocupante que la población que presenta la mayor afectación de baja visión en el mundo es la de los adultos. Se desconoce cómo esta realidad afecta social y productivamente a Costa Rica, pues no existen referencias al respecto, por lo que es fundamental realizar un análisis específico para nuestra región. Objetivo: determinar la prevalencia de la baja visión en los adultos mayores del distrito de San Isidro de El General, Pérez Zeledón, Costa Rica. Materiales y métodos: estudio transversal por muestreo aleatorio que tamizó un total de 186 adultos mayores. Se llevó a cabo una visita a la casa de habitación de cada uno de ellos y se valoró la agudeza visual. Aquellos que arrojaron resultados alterados fueron remitidos a un consultorio optométrico para evaluar con equipo especializado la baja visión. Resultados: se diagnosticaron un total de ocho pacientes (4,3 %) con baja visión. En cuatro de ellos la causa fue la catarata. Conclusión: aunque se encontró una prevalencia de baja visión, menor de la esperada en los adultos mayores, existe la posibilidad de que la atención médica no sea la más óptima, pues sus necesidades de atención no están cubiertas y predominan en ellos las enfermedades crónicas. También se confirmó la ausencia de información referente a baja visión contextualizada para Costa Rica y la importancia de desarrollar más investigación epidemiológica y clínica acerca de este tema.</p><p> </p>
Grado de adherencia a las guías clínicas de defectos refractivos por parte de los optómetras en la consulta externa de optometría en una IPS, primer semestre del 2012
Authors: Pinilla Ferro Rudy Esneda , Coy Torres Yucely Johanna , Jiménez Barbosa Wilson Giovanni 
Published: November 2015

<p><em> Objetivo: </em>Evaluar el grado de adherencia que existe a las guías clínicas de defectos refractivos por parte de los optómetras en la consulta externa de optometría, en el primer semestre de 2012. <em>Materiales y Métodos</em>: Se realizó un estudio de tipo descriptivo retrospectivo por medio de un instrumento, compuesto por preguntas dicotómicas (sí cumple o no cumple) con el fin de evaluar el grado de adherencia a la guía clínica de defectos refractivos. Se definió como universo poblacional 4.180, historias clínicas, calculándose como muestra representativa 648 de ellas, la cual, su selección se dividió, por decisión metodológica, en las tres sedes que conforman la cadena en la que se adelantó el estudio. Los datos recolectados de las historias clínicas fueron digitados y tabulados en una base de datos, los cuales se analizaron en rangos que permitieron evaluar el grado de adherencia de cada historia clínica. Los rangos por los cuales se evaluó la adherencia son los siguientes: de 0 – 20% de preguntas acertadas se considero la adherencia “Muy mala”, de 21 a 40 “mala”, de 41 a 60 “regular”, de 61 a 80 “buena” y de 81 a 100 “excelente”. <em>Resultados: </em>Se evidenció que en ningún caso se diligenció 20% o menos del total de preguntas por historia clínica, mientras que un 3,9% del total de historias se ubicó en el rango denominado “malo”. Por su parte en el rango “regular” se ubicó el 21,2% del total de historias. Los valores mas altos de evaluación los obtuvieron los rangos “bueno” y “excelente” con un total de 35,4 y 39,5% respectivamente, sin embargo, cabe resaltar que ninguna historia clínica obtuvo una calificación del 100%. <em>Conclusiones:</em> La investigación evidenció la baja adherencia a la guía de atención, ya que se observó, que ninguna de las historias clínicas estaba diligenciada en todos sus campos, por lo tanto es importante mejorar y fortalecer el rigor con el que las preguntas de las historias clínicas son diligenciadas por parte de los profesionales de optometría, ya que ello, permite tener un conocimiento más preciso de la condición de salud de los pacientes, con el fin de lograr una mayor asertividad en la toma de decisiones de la conducta clínica a seguir con cada uno de ellos.</p>
Variables y parámetros influyentes en los perfiles de ablación del láser de excímeros
Authors: Tomás-Juan Javier 
Published: November 2015

<p>El láser de excímeros permite corregir los errores refractivos miópicos, astigmáticos e hipermetrópicos mediante la ablación de la superficie corneal. Para conseguir el mejor tratamiento y la mejor corrección visual postoperatoria es necesario un buen mantenimiento y calibración de todos los parámetros del láser y de los factores ambientales de la sala de quirófano. Después de la cirugía en algunas situaciones se produce un incremento de las aberraciones, las cuales afectan en gran medida a la calidad visual del paciente. En la actualidad nuevos dispositivos basados en la ablación guiada por frente de onda y la ablación topográfica se han introducido con el objetivo de disminuir las aberraciones postoperatorias. En el presente trabajo se realiza un análisis de los principales parámetros del láser de excímeros que influyen en la ablación, como los diferentes perfiles de ablaciones corneales, que muestran cómo se relacionan directamente con la calidad visual posquirúrgica.</p><p> </p>
Hydrate Anti-Agglomerants for Sour Gases with Corrosion Inhibitor Properties
Authors: Mukherjee D. , Fowles R. , Treybig D. S. , Murugan P. 
Published: November 2015

Abstract
Hydrates can agglomerate and block pipelines causing blowouts and serious harm to personnel in addition to stopping production. They may contain as much as 30% H2S. Thermodynamic inhibitor (THI) methanol is the default method for addressing hydrate problems. Methanol can dissolve corrosion inhibitors (CIs), leading to increased corrosion rates. Alternatives are kinetic hydrate inhibitors (KHIs) but their performances are negatively affected by CIs, and they may not be suitable for sour conditions. The objective of this work was to develop anti-agglomerates (AAs) alternatives to THI and KHI that simultaneously provide corrosion protection while functioning in a sour environment.
Gas hydrate analysis was done in a gas hydrate autoclave up to 1915 psi (13,203 KPa) using 1-8% H2S, 3% CO2 and remaining CH4 at 4 °C. AAs were tested with and without alkylpyridine CI (CI-1) and torque values were used to measure performance. Selected AAs were tested to ascertain their effect on corrosion in low, medium and high salinity brine. Also corrosion studies were conducted in a benchtop autoclave at different operating parameters; temperature (22, 30, 50, 80 and 120 °C), H2S composition (4%, 20% and 35%), CO2 (3%, 4% and 10%) at total pressure of 350 psi (2413.2 kPa) and 1000 psi (6894.8 KPa). Testing was performed on 1018 carbon steel using a modified ASTM G170 method.
In hydrates testing, ≤ 2% quaternary compounds AC-1 and AC-2 (with CI-1) gave lower torque values (&lt; 2.8 Ncm) compared to the blank (12.0 Ncm) and control (CI-1 only) (9.2 Ncm). Corrosion rate in 4% H2S, 3% CO2 at 22 °C was 24 and 12.41 mpy for the blank, while AAs (with CI-1) caused decrease in corrosion rate to 0.75 and 0.9 mpy for low and medium salinity brine respectively in the water phase.
For severe conditions at 120 °C, 20% H2S and 10% CO2, the blank gave a corrosion rate of 37.83 mpy with pitting whereas 200 ppm of V-53 (33% AC-1) and V-9 (33% AC-2) provided corrosion rates of 2.26 mpy and 2.62 mpy without pitting in the brine phase. In 35% H2S and 4% CO2, the blank showed a corrosion rate of 45.78 mpy with pitting whereas 200 ppm of CI-1 and specially formulated quaternary compounds (CI-2 and CI-3) provided corrosion rates of 2.57, 2.19 and 8.87 mpy without pitting in the synthetic brine phase.
The compounds presented in this paper were able to control hydrate agglomeration up to 100 % water cut, remained active in the presence of corrosion inhibitor and demonstrated corrosion protection in sour conditions.
Applying Rock Physics Analysis to De-Risk Exploration Prospects in Mannar Basin, Sri Lanka
Authors: Malkani Anil , Routray Prabir , Majumdar Pinaki , Kumar Prem , Ghosh Biswanath , Chacko Soman 
Published: November 2015

Abstract
The study area, block SL-2007-01-001, operated by Cairn India Ltd., is located in the Mannar basin of NW offshore Sri Lankan (blue polygone in Figure-1) and contains a sedimentary section exceeding 7km, the age of which ranges from Jurassic to Recent. The large number of oil and gas discoveries in the contiguous Cauvery Basin, both in Cretaceous and Tertiary sections, makes this frontier basin an attractive candidate for exploration. In 2010 Cairn Lanka acquired 1753 sq km of 3D seismic data in order to assess the exploration potential of this deep water block. This paper focuses on the role that rock physics analysis played in the assessment, risking, and ranking of the key leads identified in the basin. Of the numerous leads identified, three were high-graded in large part due to their DHI characteristics, resulting in the Dorado and Barracuda gas discoveries (Well-A & Well-C in Figure-1, respectively), the first hydrocarbons to be discovered in the Mannar Basin. The third well, Well-B, was a dry hole.
De-risking of exploration prospects was based on quantitative seismic interpretation supported by rock physics analysis. This paper emphasizes how rock physics can add value in an exploration project to influence business decisions by reducing subsurface uncertainties. The nearest well, CY-DWN-2, that provided data for depth trends and rock physics analysis is located approximately fifty kilometers south west of the study area. Although this was a dry hole, it provided significant information on the sedimentary sequence, rock properties, and their associated seismic responses. Various "what if" scenarios were created to understand associated seismic responses. The analsyis explained the dry hole at CY-DWN-2 and highgraded the prospectivity of the Dorado lead. The latter was subsequently drilled, leading to the Dorado discovery.
Natural Productivity Analysis and Well Stimulation Strategy Optimization for the Naturally Fractured Keshen Reservoir
Authors: Zhang Fuxiang , Huang Yongjie , Yang Xiangtong , Qiu Kaibin , Yuan Xuefang , Luo Fang , Zhang Yang , Zheng Zijun 
Published: November 2015

Abstract
The Keshen reservoir is a naturally fractured, deep, tight gas sandstone reservoir under high-tectonic stress. Stimulation is critical to the successful development of the Keshen gas field. However, due to the heterogeneity of the natural fracture system in the reservoir, there is large variation in natural productivity from production wells, which mandates different types of stimulation operations from simple acidizing to massive hydraulic fracturing. Hence, to improve the efficiency of reservoir stimulation and overall performance of the reservoir development, reliably evaluating the natural productivity from production wells and optimizing well stimulation strategy (by selecting appropriate stimulation operations) are required.
To this end, single well production history matches were conducted to calculate the natural fracture (NF) permeabilities for 12 acidizing wells with known matrix petrophysical properties. It was found out that the NF permeability is clearly correlated to the intersection angle ((, angle between maximum horizontal stress and NF strike) and Young's modulus (E), based on detailed natural fracture interpretation and geomechanics analysis. By using a correlation with the intersection angle and Young's modulus, the NF permeabilities for seven hydraulic fractured wells with large size treatment were obtained and the natural productivity for each well was predicted. By comparing predicted natural productivity with actual post-stimulation productivity, the productivity enhancement by hydraulic fracturing treatment was determined. The comparison showed that the productivity improvements by hydraulic fracturing treatment were very limited and unnecessary for the wells with high natural productivity, while improvements were substantial for others. Subsequently, the well stimulation selection criterion was formulated, which classified wells into three categories based on the natural productivity, and specified stimulation method was recommended for each well category, respectively.
This paper shows an example: the natural productivity of a newly drilled well was predicted, and massive hydraulic fracturing was selected based on the stimulation treatment selected criterion. The well was successfully stimulated with absolute open flow (AOF) of 3.6 MMm3/d, which doubled the natural productivity.
The workflow used to estimate the natural productivity of the tectonically active Keshen reservoir and to establish the well stimulation selection criterion, and their application and validation, which are rarely published previously, are presented in this paper.
Failure Analysis of Carbon Steel Sub Sea Water Injection Pipelines and Their Protection for Good IOR
Authors: Bhardwaj Anil , Kumar Bipin , Prasad Sangeeta R. , Srivastava S. K. 
Published: November 2015

Abstract
Water injection is one of the methods for maximizing oil production and improving oil recovery by way of maintaining reservoir pressure. It entails injection of water in sufficient quantities with acceptable quality into the appropriate zones of the reservoir in a cost efficient manner. Treated water is transmitted from treatment to well generally through carbon steel pipelines; as there are flexible pipelines, internally coated pipelines being used for water injection also. And this paper is solely for carbon steel pipelines. The corrosion of these water injection pipelines is a major issue for the Oil & Gas industry with a view to preserve the reservoir permeability and integrity of the pipelines.
A few case studies pertaining to failure of API 5L carbon steel subsea water injection pipelines with their root cause analysis are presented in this paper. In order to identify the cause and mechanism of failure, detailed laboratory and analytical investigations were carried out with a view to characterize the material property as well as to evaluate the corrosivity of operating environment. Studies like visual inspection, non destructive testing, corrosion product analysis, elemental compositional analysis, metallographic investigations, inclusion content test, hardness testing, tensile strength studies, impact test, stereomicrscopy, scanning electron microscopic (SEM) coupled with energy dispersive spectroscopy (EDS) studies, have been carried out. Process parameters, operating & maintenance practices, chemical treatment program with quality parameters etc. have also been critically examined.
Pipeline material was found to conform to the specification API 5L. The analysis showed that the most probable cause of the failure of the pipeline was under-deposit/grooving corrosion, which started with oxygen and Microbiologically Influenced Corrosion due to Sulphate Reducing Bacteria and was subsequently supported by very low flow velocities in those pipelines. The stagnant water and the formation of thick deposit consisting of corrosion product, sludge or suspended solids and biomass as a result of proliferation of bacterial colonies were the conditions for attack to set off. Galvanic corrosion further accelerated the metal loss process as grooving/channeling resulting into failure at 6 O'clock position. Presence of large number of inclusions in some of pipeline materials was an additional cause of accelerated corrosion process.
On the basis of root cause failure analysis, the major integrity threats to the water injection pipelines resulting from process control were identified. Accordingly, preventive and remedial measures essential for preserving integrity of water injection pipelines have been suggested. Implementation of good operating and maintenance practices, robust quality control measures, continuous monitoring of corrosion trends, prompt corrective actions are the key requisites to abate failures due corrosion.
Novel Use of Spent Amine Solution of Gas Sweetening Plant as H2S Scavenger, Corrosion Inhibitor & Biocide
Authors: Shukla A. K. , Chauhan P. S. , Sahu S. K. 
Published: November 2015

Abstract
Gas Sweetening is the most important operation of any Natural Gas Processing Plant. At ONGC, Uran Plant, gas received from offshore is combined with the crude stabilization off gas (CSU off gas) and condensate fractionating off gas and then passed through Gas Sweetening Units (GSU) to remove CO2 and H2S from the gas before further processing in LPG and EPRU for extraction of value added products.
GSU plant was originally designed for and operated with gas sweetening solvent system consisting of DIPA (Di-Isopropanol Amine) & Sulfolane. Contamination of solvent by amine degradation products and comingled composition of solvent system became a bottleneck for increasing gas processing capacity and to enhance plant capacity, comingled solvent system was replaced with a third generation solvent system consisting of MDEA, Sulfolane & Piperazine.
After change-over, approximately 500 MT of comingled amine solution having a mixture of DIPA, MDEA, Sulfolane, Piperazine and Oxazolidone (an amine degradation product), was available as a hazardous waste. Owing to the complexity of the mixture having five different chemicals, reclaiming of useful solvent from the comingled solution was ruled out and the only option left was its disposal by incineration.
Keeping in view the large quantity of spent solution & huge cost of disposal, study was undertaken to explore possibility of use of spent solution for some other in house applications.
Extensive lab studies carried out to evaluate anti-corrosive, anti-microbial and H2S scavenging properties of spent solution & found that amine solution has adequate H2S Scavenging & corrosion inhibition efficiency at 400–500 ppm and bactericidal efficiency at 30 ppm of dosage.
The subsequent field trial at 400–500 ppm of doses in one of the Oil trunk line having three phase flow (oil, associated gas and water) for quite a period has shown substantial reduction of H2S content in the off gas.