bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lessons Learned From Hydraulic Fracturing the First Exploratory Shale Gas Well in Egypt
Authors: Mohamed Mohamed Salah , Meguid Ahmed Abdel , Wang Qiang , El-Maghraby Omar 
Published: August 2016

Abstract
Egypt's Western Desert contains a series of basins underlain by organic-rich shales that provide the source for conventional hydrocarbon. The primary objectives for exploring the gas-rich shale plays and unconventional reservoirs in the Western Desert were to evaluate the Middle Jurassic Khatatba source rock reservoir qualities, demonstrate the availability of reserves, and identify optimal technology to maximize productivity of unconventional low-permeability reservoirs, stimulation, and testing strategies.
In 2014, a vertical exploratory data well was drilled and completed in the appraisal program before the completion of horizontals in this formation. Logs, core testing, and analysis service data were performed on or collected from this well. A stimulation model was built, which integrated petrophysical and geomechanical data. This model was used to aid the completion and stimulation design, including fracturing fluids and proppant selections. One-stage hydraulic fracturing was implemented, and the well was then flowed back and produced.
The Khatatba Shale was systematically studied in this work. Various methods were used to understand this source rock. A geological study identified the lithostratigraphic section of the Khatatba Shale formations by collecting core samples. Core tests measured total organic carbon (TOC), brittleness, and sensitivity to fluid. These understandings helped reduce uncertainty during hydraulic fracturing operations. A successful hydraulic fracturing treatment was performed for this formation, which showed that low-viscosity fracture fluid can be used as the treatment fluid to carry proppant into the formation. During fracturing, near-wellbore (NWB) multiple fractures can be an issue. From an operational point of view, there might be options better than performing high-rate fracturing treatments. The lessons learned from this work and presented in this paper helped define completion and stimulation technologies for horizontal wells.
This paper presents hydraulic fracturing treatment of the first shale gas well in Egypt for the Khatatba formation. Lessons learned about geochemical, rock mechanical, and petrophysical properties of this shale formation and their effects on hydraulic fracturing and production formed the basis for subsequent development of various shale plays in Egypt and worldwide.
Producción y pérdida de nitrato en Brachiaria humidicola y Panicum maximum en el valle del río Sinú
Authors: Espinosa Manuel , Marrugo José , Hurtado María , Reza Sony 
Published: August 2016

Las pérdidas de nitrógeno a partir de la nitrificación de las fertilizaciones nitrogenadas generan contaminación por las emisiones de óxido nitroso y lixiviación de nitrato. Los reportes de Brachiaria como inhibidor biológico de la nitrificación fueron evaluados al determinar las pérdidas de nitrato de Brachiaria humidicola CIAT 679 (planta indicadora de inhibición biológica de nitrificación) y Panicum maximum cv. tanzania (planta no inhibidora). Para la producción de nitrato se empleó la técnica de suelo incubado y para las pérdidas de nitrato se emplearon resinas de intercambio iónico PRSTM Probes. Los tratamientos de fertilización nitrogenada fueron de 0, 150 y 300 kg ha-1 por año; las resinas se instalaron a tres profundidades en el suelo, los análisis de laboratorio se realizaron mediante espectroscopía de ultravioleta visible con longitud de onda de 410 nm para nitrato. B. humidicola redujo las producciones de nitrato en el suelo y las dosis de nitrógeno no generaron variaciones en las producciones, lo que evidenció un efecto en la inhibición de la nitrificación. Las pérdidas de nitrato, se redujeron después de 18 meses en la B. humidicola; y para P. maximum puede evitar las pérdidas de nitrato por su habilidad de tomar el nitrógeno en forma amoniacal del suelo, pero no reduce la producción de nitrato, ya que no inhibe la nitrificación. Los suelos dedicados a la producción ganadera con la pastura B. humidicola pueden reducir las producciones y las pérdidas de nitrato. P. maximum, por su habilidad y buena respuesta a la fertilización nitrogenada pudo reducir las pérdidas, pero no logró reducir las producciones de nitrato.
Análisis de la diversidad genética de accesiones de Theobroma cacao L. del banco de conservación a cargo de Corpoica
Authors: Sánchez Inés , Zárate Luz Angela , Gallego Gerardo , Tohme Joe 
Published: August 2016

Se estudió la diversidad genética presente en el banco de germoplasma de Theobroma cacao L. que se conserva en la Estación Experimental ‘La Suiza’ de la Corporación Colombiana de Investigación Agropecuaria –Corpoica– en el departamento de Santander. A tal fin se caracterizaron 100 genotipos de cacao mediante isoenzimas, RFLPs, RAPDs y SSR, utilizando 25 microsatélites publicados previamente en el GenBank. El porcentaje de amplificación obtenido fue del 100% lo que permitió identificar 168 alelos. Los niveles de polimorfismo variaron entre 2 y 14 alelos por locus con un promedio de 6,72. Las tasas de similaridad y distancia genética de Nei y Li entre los 100 genotipos se obtuvieron mediante el programa Ntsys v2.1® y se construyó un dendrograma con el algoritmo Upgma. Los valores obtenidos fueron superiores a 0,45 y en el dendrograma se identificaron dos grupos genéticos principales y varios subgrupos internos. Los resultados obtenidos se consideran un avance importante en el conocimiento de la diversidad genética de accesiones de Theobroma cacao L. conservadas en bancos de germoplasma y son de gran utilidad para desarrollar e implementar programas de mejoramiento y conservación del cacao basados en información genética relativa a características fenotípicas que favorezcan una mejor calidad, mayor producción y rentabilidad del cultivo en Colombia.
Bacterias anaerobias del suelo responsables de la muerte súbita bovina en sabanas tropicales: investigaciones realizadas en Colombia
Authors: Ortiz Diego , Villamil Luis Carlos 
Published: August 2016

El estudio de las clostridiosis en Colombia debe ser una prioridad para nuestras autoridades sanitarias debido al impacto sanitario que causan estas bacterias en la salud animal. Así mismo, la agudeza de los signos y síntomas clínicos de estas patologías, y el hecho que afectan animales en buenas condiciones de carne, hacen que tengan fuerte impacto económico. Se presenta una revisión de las principales investigaciones realizadas sobre clostridiosis en los últimos años, algunas publicadas en literatura científica y otras en literatura gris. Se hace énfasis en la muerte súbita bovina, condición que incluye varias patologías entre las que se destacan el botulismo bovino producido por las neurotoxinas tipo C y D de Clostridium botulinum, el carbón sintomático (pierna negra) causado por Clostridium chauvoei y en menor proporción el tétanos, causado por el Clostridium tetani. Se reportan algunos avances en la estandarización de metodologías de diagnóstico en laboratorio y en campo, lo mismo que resultados de estudios epidemiológicos desarrollados en zonas afectadas por estas enfermedades. Finalmente, se presenta una visión prospectiva sobre la investigación en los clostridios y las clostridiosis, lo mismo que algunas propuestas de solución a la problemática discutida.
Incidencia de los márgenes sobre el control biológico natural de Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) en cultivos de arroz
Authors: Vilaseca Carlos Javier , Baptiste Luis Guillermo , López-Ávila Aristóbulo 
Published: August 2016

Múltiples estudios han mostrado los beneficios ambientales, económicos y productivos que se pueden generar al incluir vegetación natural en los márgenes de los cultivos. Esto se debe principalmente a que la presencia de hábitats naturales favorece factores bióticos y abióticos que pueden afectar negativamente las plagas. Con base en lo anterior, esta investigación tuvo como objetivo evaluar y comparar el efecto de márgenes compuestos por plantaciones de palma de aceite y bosques de galería sobre el control biológico natural de Spodoptera frugiperda en cultivos de arroz. Para esto, se seleccionó un área de estudio en el piedemonte llanero colombiano (Villanueva, Casanare), compuesta por grandes extensiones de cultivos de arroz rodeados por plantaciones de palma de aceite y bosques de galería. Se evaluó la abundancia de S. frugiperda en estados de larva y adulto, el parasitismo de huevos y larvas, y la diversidad de enemigos naturales y de otros artrópodos. Se observó aumento en la presencia de insectos benéficos y disminución de la población de la plaga en los estadios de larva y adulto en cercanías a los márgenes. Se identificó la importancia de parasitoides como Apanteles marginiventris y depredadores, en especial correspondientes al orden Odonata para el control natural de S. frugiperda. Se encontró que tanto las plantaciones de palma de aceite como los bosques de galería promueven el control biológico natural de S. frugiperda; sin embargo, aspectos como la baja calidad del hábitat y la aplicación constante de insumos químicos afectaron los resultados significativamente.
Comparación de tres tratamientos para la crioconservación de serovares de Leptospira en nitrógeno líquido
Authors: Higuera Ligia Denise Torres , Ortega Diego Ortiz , Bautista José Luis Rodríguez , Burbano Rocío Esperanza Patiño 
Published: August 2016

La preservación de bacterias pertenecientes al género Leptospira por métodos tradicionales -repiques frecuentes del cultivo- es costosa, dispendiosa y puede generar pérdidas de las características genéticas del cultivo. En el presente estudio se estandarizó una técnica de crioconservación en nitrógeno líquido para seis serovares de Leptospira -Pomona, Hardjoprajitno, Canicola, Icterohaemorrhagiae, Grippotyphosa y Bratislava-, usando como agente crioprotector el dimetil sulfóxido (DMSO) a una concentración final de 2% y una tasa de enfriamiento de 1°C/min y se comparó con el uso de glicerol a concentraciones finales de 0,2% y 10%. Los tres métodos se evaluaron mediante la determinación de la viabilidad bacteriana antes y después de la congelación (a 0, 30, 90, 180, 270 y 360 días) por recuento bacteriano en cámara. Los datos se sometieron a análisis de varianza y comparación por parejas usando la prueba de Bonferroni. La presencia de glicerol al 10% (concentración final) en el medio crioconservante disminuyó la viabilidad de los serovares. La técnica de criopreservación en nitrógeno líquido con DMSO al 2% y glicerol al 0,2% (concentraciones finales) permitió la exitosa conservación de los seis serovares de Leptospira. El método de criopreservación aseguró una alta viabilidad, lo que disminuyó costos y tiempo en su ejecución y demostró ser un mejor método de conservación a largo plazo en relación con el mantenimiento tradicional por subcultivos periódicos.
Use of Electronic Health Data to Estimate Heart Failure Events in a Population-Based Cohort with CKD
Authors: Floyd James S. , Wellman Robert , Fuller Sharon , Bansal Nisha , Psaty Bruce M. , de Boer Ian H. , Scholes Delia 
Published: August 2016

Background and objectives
Studies that use electronic health data typically identify heart failure (HF) events from hospitalizations with a principal diagnosis of HF. This approach may underestimate the total burden of HF among persons with CKD. We assessed the accuracy of algorithms for identifying validated HF events from hospitalizations and outpatient encounters, and we used this validation information to estimate the rate of HF events in a large CKD population.

Design, setting, participants, & measurements
We identified a cohort of 15,141 adults age 18–89 years with an eGFR<60 ml/min per 1.73 m2 from 2008 to 2011. Potential HF events during follow-up were randomly sampled for validation with medical record review. Positive predictive values from the validation study were used to estimate the rate of validated HF events in the full cohort.

Results
A total of 1864 participants had at least one health care encounter that qualified as a potential HF event during 2.7 years of mean follow-up. Among 313 potential events that were randomly sampled for validation, positive predictive values were 92% for hospitalizations with a principal diagnosis of HF, 32% for hospitalizations with a secondary diagnosis of HF, and 70% for qualifying outpatient HF encounters. Through use of this validation information in the full cohort, the rate of validated HF events estimated from the most comprehensive algorithm that included principal and secondary diagnosis hospitalizations and outpatient encounters was 35.2 events/1000 person-years (95% confidence interval, 33.1 to 37.4), compared with 9.5 events/1000 person-years (95% confidence interval, 8.7 to 10.5) from the algorithm that included only principal diagnosis hospitalizations. Outpatient encounters accounted for 20% of the total number of validated HF events.

Conclusions
In studies that rely on electronic health data, algorithms that include hospitalizations with a secondary diagnosis of HF and outpatient HF encounters more fully capture the burden of HF, although validation of HF events may be necessary with this approach.
Efficacy and Safety of Liraglutide Added to Insulin Treatment in Type 1 Diabetes: The ADJUNCT ONE Treat-To-Target Randomized Trial
Authors: Mathieu Chantal , Zinman Bernard , Hemmingsson Joanna Uddén , Woo Vincent , Colman Peter , Christiansen Erik , Linder Martin , Bode Bruce ,   for the ADJUNCT ONE Investigators
Published: August 2016

OBJECTIVETo investigate whether liraglutide added to treat-to-target insulin improves glycemic control and reduces insulin requirements and body weight in subjects with type 1 diabetes.RESEARCH DESIGN AND METHODSA 52-week, double-blind, treat-to-target trial involving 1,398 adults randomized 3:1 to receive once-daily subcutaneous injections of liraglutide (1.8, 1.2, or 0.6 mg) or placebo added to insulin.RESULTSHbA1c level was reduced 0.34–0.54% (3.7–5.9 mmol/mol) from a mean baseline of 8.2% (66 mmol/mol), and significantly more for liraglutide 1.8 and 1.2 mg compared with placebo (estimated treatment differences [ETDs]: 1.8 mg liraglutide −0.20% [95% CI −0.32; −0.07]; 1.2 mg liraglutide −0.15% [95% CI −0.27; −0.03]; 0.6 mg liraglutide −0.09% [95% CI −0.21; 0.03]). Insulin doses were reduced by the addition of liraglutide 1.8 and 1.2 mg versus placebo (estimated treatment ratios: 1.8 mg liraglutide 0.92 [95% CI 0.88; 0.96]; 1.2 mg liraglutide 0.95 [95% CI 0.91; 0.99]; 0.6 mg liraglutide 1.00 [95% CI 0.96; 1.04]). Mean body weight was significantly reduced in all liraglutide groups compared with placebo ETDs (1.8 mg liraglutide −4.9 kg [95% CI −5.7; −4.2]; 1.2 mg liraglutide −3.6 kg [95% CI −4.3; −2.8]; 0.6 mg liraglutide −2.2 kg [95% CI −2.9; −1.5]). The rate of symptomatic hypoglycemia increased in all liraglutide groups (estimated rate ratios: 1.8 mg liraglutide 1.31 [95% CI 1.07; 1.59]; 1.2 mg liraglutide 1.27 [95% CI 1.03; 1.55]; 0.6 mg liraglutide 1.17 [95% CI 0.97; 1.43]), and hyperglycemia with ketosis increased significantly for liraglutide 1.8 mg only (event rate ratio 2.22 [95% CI 1.13; 4.34]).CONCLUSIONSLiraglutide added to insulin therapy reduced HbA1c levels, total insulin dose, and body weight in a population that was generally representative of subjects with type 1 diabetes, accompanied by increased rates of symptomatic hypoglycemia and hyperglycemia with ketosis, thereby limiting clinical use in this group.
Concentration changeability of phosphorus, calcium and magnesium in selected partial drainage basins of the River Drwęca
Authors: Pius Bożena 
Published: August 2016

Abstract
The paper presents the results of the research conducted between November 2008 and October 2009. The research included seasonal dynamics of the flow and runoff of phosphorus compounds (TP and P-PO4
3-), as well as Ca2+ and Mg2+ from 13 partial drainage basins of the River Drwęca. Water levels were registered automatically every day by recorders, and measurements of the flow were conducted once a month. Major differences were found in the water abundance as indicated by specific discharges in individual, partial drainage basins: from 1.87 dm3 s-1 km-2 (Lubianka - a lower part of the River Drwęca drainage basin) to 8.22 dm3 s-1 km-2 (Gizela - an upper part of the River Drwęca drainage basin). The studied rivers were characterised by very diverse average content of total phosphorus compounds: from 0.047 mg dm-3 (Iłga) to 0.816 mg dm-3 (Sandela); calcium: from 47.18 mg dm-3 (Iłga) to 131.65 mg dm-3 (Trynka); and magnesium: from 9.71 mg dm-3 (Wel) to 36.76 mg dm-3 (Struga Rychnowska). Analysis of variance carried out on hydrochemical properties of the studied rivers divides the rivers into two separate groups: rivers with much higher content of phosphorus, calcium and magnesium compounds (Struga Rychnowska, Trynka, Ruziec, Lubianka, Kujawka, Sandela and Gizela), and a group of rivers with low content of these compounds (Brynica, Brodniczanka, Skarlanka, Wel, Iłga).
Fine structural detection of calcium ions by photoconversion
Authors: Poletto V. , Galimberti V. , Guerra G. , Rosti V. , Moccia F. , Biggiogera M. 
Published: August 2016

We propose a tool for a rapid high-resolution detection of calcium ions which can be used in parallel with other techniques. We have applied a new approach byÂ photo-oxidation of diaminobenzidine in presence of the emission of an excited fluorochrome specific for calcium detection. This method combines the selectivity of available fluorophores to the high spatial resolution offered by transmission electron microscopy to detect even fluorescing molecules even when present in low amounts in membrane-bounded organelles. We show in this paper that Mag-Fura 2 photoconversion via diaminobenzidine oxidation is an efficient way for localizing Ca2+ ions at EM level, is easily carried out and reproducible, and can be obtained on a good amount of cells, since the exposition in our conditions is not limited to the direct irradiation of the sample via an objective but obtained with a germicide lamp. The end product is sufficiently electron dense to be detected clearly when present in sufficient amount within a membrane boundary.
Decreasing age at first anal intercourse among men who have sex with men in China: a multicentre cross‐sectional survey
Authors: Zou Huachun , Xu Junjie , Hu Qinghai , Yu Yanqiu , Fu Gengfeng , Wang Zhe , Lu Lin , Zhuang Minghua , Chen Xi , Fu Jihua , Zhou Zhenhai , Geng Wenqing , Jiang Yongjun , Shang Hong 
Published: August 2016

IntroductionLiterature on the age at first anal intercourse (AFAI) among men who have sex with men (MSM) is limited. We aimed to elucidate the evolution of AFAI and the factors associated with early AFAI, based on a large sample of MSM in China.MethodsWe collected information on the demographics and sexual behaviours of MSM from seven large cities in China from 2012 to 2013. Blood samples were collected for HIV serology. AFAI was calculated for MSM born in different time periods. Linear regression models were used to explore factors associated with younger AFAI.ResultsA total of 4491 MSM (median age: 27 years, median AFAI: 21 years) were recruited. Median AFAI decreased steadily from 33 years of age among MSM born from 1940 to 1959 to 18 years of age among MSM born from 1990 to 1996. Factors significantly associated with younger AFAI included more recent birth cohort, being unmarried or living with a male partner, being a student or industry worker, the gender of the first partner being male, and using Rush or Ecstasy in the past six months (p for all <0.05).ConclusionsAFAI among MSM in China has considerably decreased over the past few decades. The decreasing AFAI and factors associated with younger AFAI point to the necessity of early sex education and control of recreational drug use among MSM in China.
Arctic springtime observations of volatile organic compounds during the OASIS‐2009 campaign
Authors: Hornbrook Rebecca S. , Hills Alan J. , Riemer Daniel D. , Abdelhamid Aroob , Flocke Frank M. , Hall Samuel R. , Huey L. Gregory , Knapp David J. , Liao Jin , Mauldin Roy L. , Montzka Denise D. , Orlando John J. , Shepson Paul B. , Sive Barkley , Staebler Ralf M. , Tanner David. J. , Thompson Chelsea R. , Turnipseed Andrew , Ullmann Kirk , Weinheimer Andrew J. , Apel Eric C. 
Published: August 2016

AbstractGas‐phase volatile organic compounds (VOCs) were measured at three vertical levels between 0.6 m and 5.4 m in the Arctic boundary layer in Barrow, Alaska, for the Ocean‐Atmosphere‐Sea Ice‐Snowpack (OASIS)‐2009 field campaign during March–April 2009. C4‐C8 nonmethane hydrocarbons (NMHCs) and oxygenated VOCs (OVOCs), including alcohols, aldehydes, and ketones, were quantified multiple times per hour, day and night, during the campaign using in situ fast gas chromatography‐mass spectrometry. Three canister samples were also collected daily and subsequently analyzed for C2‐C5 NMHCs. The NMHCs and aldehydes demonstrated an overall decrease in mixing ratios during the experiment, whereas acetone and 2‐butanone showed increases. Calculations of time‐integrated concentrations of Br atoms, ∫[Br]dt, yielded values as high as (1.34 ± 0.27) × 1014 cm−3 s during the longest observed ozone depletion event (ODE) of the campaign and were correlated with the steady state Br calculated at the site during this time. Both chlorine and bromine chemistry contributed to the large perturbations on the production and losses of VOCs. Notably, acetaldehyde, propanal, and butanal mixing ratios dropped below the detection limit of the instrument (3 parts per trillion by volume (pptv) for acetaldehyde and propanal, 2 pptv for butanal) during several ODEs due to Br chemistry. Chemical flux calculations of OVOC production and loss are consistent with localized high Cl‐atom concentrations either regionally or within a very shallow surface layer, while the deeper Arctic boundary layer provides a continuous source of precursor alkanes to maintain the OVOC mixing ratios.
A synthetic study to evaluate the utility of hydrological signatures for calibrating a base flow separation filter
Authors: Su Chun‐Hsu , Peterson Tim J. , Costelloe Justin F. , Western Andrew W. 
Published: August 2016

AbstractEstimation of base flow from streamflow hydrographs has been a major challenge in hydrology for decades, leading to developments of base flow separation filters. When without tracer or groundwater data to calibrate the filters, the standard approach to apply these filters in practice involves some degrees of subjectivity in choosing the filter parameters. This paper investigates the use of signature‐based calibration in implementing base flow filtering by testing seven possible hydrological signatures of base flow against modeled daily base flow produced by Li et al. (2014) for a range of synthetic catchments simulated with HydroGeoSphere. Our evaluation demonstrates that such a calibration method with few selected signatures as objectives is capable of calibrating a filter–Eckhardt filter–to yield satisfactory base flow estimates at daily, monthly and long‐term time scales, outperforming the standard approach. The best performing signatures can be readily derived from streamflow time series. While their performance depends on the catchment characteristics, the catchments where the signature method performs can be distinguished using commonly‐used descriptors of flow dynamics.