bluuebunny/crossref_metadata_2025 huggingface dataset:
Estratégias de cuidado e suporte em saúde mental entre mulheres assentadas
Authors: Costa Maria da Graça , Dimenstein Magda , Leite Jáder
Published: May 2015

Neste estudo, pesquisou-se sobre as estratégias de cuidado e apoio psicossocial oferecidas a mulheres adultas residentes de assentamentos rurais do Brasil. Aplicou-se o Self-Reporting Questionnaire (SRQ-20) para identificar a prevalência de Transtornos Mentais Comuns (TMC) e entrevistas semiestruturadas com as quais foram apresentadas hipóteses positivas de TMC. Os resultados indicaram que, apesar da alta prevalência de TMC (43.6%), essas mulheres não recorrem à rede de saúde para abordar essas questões e o único recurso oferecido na atenção primária é a prescrição com ansiolíticos. A religiosidade e o trabalho se destacam como as estratégias mais importantes para o apoio à saúde mental dessas mulheres.
Perspectiva Cultural del Desarrollo Infantil en las Instituciones de Protección
Authors: Galvis Serna Esteban
Published: May 2015

Tradicionalmente, el desarrollo de los niños que viven y crecen en los contextos de protección se ha entendido a partir de las perspectivas normativas de desarrollo. Esto ha llevado a que se asuma el desarrollo del niño en acogimiento residencial con la misma lógica implementada para aquellos niños criados por sus padres, lo cual conduce a un desconocimiento del contexto cultural inherente al proceso de desarrollo infantil. Reconocer la relación entre la cultura institucional y el desarrollo del niño que vive en un contexto de protección implica considerar el proceso de constitución entre el desarrollo y el trasfondo cultural. Ello exige una aproximación metodológica diferente a la tradicional.
Comprensión y Producción Textual Narrativa en Estudiantes de Educación Primaria
Authors: Guzmán Torres Leidy Tatiana , Fajardo Valbuena Martha Elizabeth , Duque Aristizábal Claudia Patricia
Published: May 2015

Por medio de un enfoque mixto, se caracterizó la comprensión y producción textual narrativa en estudiantes de educación primaria (primero y segundo grado), así como aspectos psicosociales (valor social de la lectura y hábito lector) y contextuales (interacciones cognitivas y afectivas docente-niños) en docentes de educación primaria de tres instituciones educativas. Se encontró que los estudiantes tuvieron un desempeño medio alto en producción textual y comprensión literal, y bajo en comprensión inferencial. Además, se observó que la mayoría de las docentes son lectoras ocasionales, emplean interacciones cognitivas unidireccionales, ofrecen un mediano apoyo emocional a sus estudiantes y valoran la lectura como una herramienta instrumental y lúdica.
Programas Educativos Universitarios Para Mayores: Evaluación de su Impacto en la Autopercepción del Apoyo Social y la Salud Mental
Authors: Lucas-Molina Beatriz , Pérez-Albéniz Alicia , Fonseca-Pedrero Eduardo , Ortuño-Sierra Javier
Published: May 2015

Algunos estudios indican que los programas universitarios para mayores pueden tener un impacto positivo en la autopercepción del apoyo social y la salud de los participantes. Sin embargo, dichos estudios no evalúan estas variables con instrumentos de medida estandarizados y grupos de control dentro y fuera del programa. En el presente trabajo se utilizó un grupo experimental y dos grupos control que fueron evaluados en dos momentos con instrumentos estandarizados. Los resultados no confirmaron los efectos beneficiosos esperados de los programas. Es necesario seguir profundizando en esta línea de actuación y explorar el efecto de variables socioafectivas en estudios longitudinales.
Diseño y Validación de un Cuestionario de Imagen Corporal para Personas en Situación de Discapacidad Física
Authors: Botero Soto Paula Andrea , Londoño Pérez Constanza
Published: May 2015

El presente estudio pretendió diseñar y validar el Cuestionario de Imagen Corporal para Personas con Discapacidad Física. La muestra incidental estuvo conformada por 114 personas de 18 a 50 años, residentes en Bogotá, que presentaban una discapacidad física. Se diseñaron 40 ítems, evaluados por jueces expertos, se aplicaron a la muestra y se definieron los criterios de calificación. El análisis factorial evidenció la existencia de tres factores constituyentes del constructo de imagen corporal: atractivo, funcionalidad y satisfacción. El cuestionario cumplió con las condiciones de confiabilidad y validez necesarias, por lo que se concluye que es posible utilizarlo, aunque es preciso continuar con el proceso de validación.
Size control of gas phase grown silicon nanoparticles by varying the plasma OFF time in silane pulsed plasma
Authors: Mohan A. , Poulios I. , Schropp R.E.I. , Rath J.K.
Published: May 2015

Silicon nanoparticles are synthesized by very high frequency Plasma Enhanced Chemical Vapor Deposition (vhf-PECVD) in the gas phase. Pulsed plasmas are used to obtain particles with a narrow size distribution. The role of plasma OFF times is studied to tailor the size of the silicon nanoparticles. Various plasma OFF times are chosen, both longer- and shorter -than the residence time of the gases in the discharge. Time resolved optical emission spectroscopy (TROES) studies provide additional information about the growth precursor dynamics during plasma modulation. The size and the size distribution studies of the particles are done with transmission electron microscopy (TEM). These studies reveal that a plasma OFF time longer than the residence time is favorable for the formation of quantum sized silicon particles.
Wet Chemical and UV-Vis Spectrometric Iron Speciation in Quenched Low and Intermediate Level Nuclear Waste Glasses
Authors: Weaver Jamie L. , Wall Nathalie A. , McCloy John S.
Published: May 2015

In this study wet chemical methods combined with UV-Vis spectroscopy were performed to quantify Fe(II)/Fe(III) ratios and total iron content of quenched alkali alumino-boro-silicate (simulated nuclear waste) glasses, applying a colorimetric method. We report lessons learned from experimental challenges encountered associated with the colorimetric method, where 1,10 phenanthroline method is complexed with dissolved glass powder and the resulting solution measured for absorbance at 520 nm to determine Fe(II). To obtain total iron, the solution was then equilibrated with a mild reducing agent to chance all Fe to Fe(II), and the absorbance measured again at 520 nm. These absorbance values allowed for calculation of the Fe(II)/Fe(III) ratio, and the total iron content in the glasses. Total Fe measured is somewhat higher than as-batched target values for waste glasses, but very accurate for reference BCR-2G glass. All quenched alumino-boro-silicate glasses analyzed showed a Fe(II)/Fe(III) ratio between 0.06 (± 0.01) and 0.04 (± 0.01). These values are consistent with those obtained for similar glass compositions melted under analogous conditions, indicating a composition of ca. 94-96% Fe(III).
Thin film silicon solar module encapsulation technology research
Authors: Cheng Yu , Hu Huayi , Gao Zhihong , Zhou Ke , Wang Xiaona , Xiang Shihong , Chen Xiaohui
Published: May 2015

The encapsulation failure is a serious problem which leads to power degradation and life time reduction of silicon based thin film solar module. Therefore, the encapsulation material and related technology research and development become more and more important. This article describes some different junction box and middle foil encapsulation technology of the silicon based thin film solar module, different encapsulation materials and processes are compared and their impact on the manufacturing cost and module performance are discussed. The aim of this study is to find an appropriate solution of module encapsulation failure.
A Sampling Method for Semi-Quantitative and Quantitative Electron Microprobe Analysis of Glass Surfaces
Authors: Weaver Jamie L. , Reiser Joelle , Neill Owen K. , McCloy John S. , Wall Nathalie A.
Published: May 2015

The determination of the long-term stability and corrosion of vitrified nuclear waste is an important aspect of research for the U.S. Department of Energy (DOE). It is necessary to understand the rate and mechanisms of Nuclear Waste Glass (NWG) corrosion to determine whether or not the glassy matrix will be able to retain radionuclides for the required repository performance time period. Glass corrosion and the rate of glass corrosions is determined by both chemical and microscopy. Electron Microprobe Analysis (EPMA) is a common and powerful method utilized in the examination of the chemographic difference between corroded and uncorroded NGWs. In this work, two forms of quantitative and semi-quantitative EPMA methods are defined by optimizing the instruments counting statistics against a standard glass and NIST minerals that have compositions similar to the glasses under examination. Data collected on both the planar and cross-sectioned surfaces of an unaltered simulated NWG by Standard based Wavelength Dispersive Spectroscopy (WDS) was found to be comparable to the theoretical composition of the glass. Conventional standardless Energy Dispersive Spectroscopy (EDS) data collected on the same surfaces was not comparable. However, standard-based EDS analysis is shown to be able to discriminate between unaltered and corroded glass surfaces.
Novel Linear and Hyperbranched Polythiophene Derivatives Containing Diketopyrrolopyrroles as Linking Groups
Authors: Yang Sheng-Hsiung , Hsieh Chia-Hao
Published: May 2015

The goal of this research is to synthesize novel linear and hyperbranched polythiophene derivatives containing diketopyrrolopyrrole (DPP) as linking groups, and to investigate thermal, optical, electrochemical, and photovoltaic properties of those derivatives. Polymers with high regioregularity were synthesized via the Universal Grignard metathesis polymerization. Those linear or hyperbranched polythiophenes containing DPP bridging moieties showed higher molecular weights and better thermal stability compared with normal P3HT. The UV-vis absorption spectra of the DPP-containing polymers are similar to that of P3HT in film state, while they show distinct attenuation in fluorescent emission. Finally, all polymers were blended with PC61BM and used as active layers for fabrication of inverted solar devices. The devices based on those DPP-containing polythiophenes revealed the open-circuit voltage (VOC) of 0.55–0.58 V, the short-circuit current (JSC) of 8.62–16.21 mA/cm2, the fill factor (FF) of 36–41%, and the power conversion efficiency (PCE) of 1.73–3.74%.
Electron Beam Effects during In-Situ Annealing of Self-Ion Irradiated Nanocrystalline Nickel
Authors: Muntifering Brittany , Dingreville Rémi , Hattar Khalid , Qu Jianmin
Published: May 2015

Transmission electron microscopy (TEM) is a valuable methodology for investigating radiation-induced microstructural changes and elucidating the underlying mechanisms involved in the aging and degradation of nuclear reactor materials. However, the use of electrons for imaging may result in several inadvertent effects that can potentially change the microstructure and mechanisms active in the material being investigated. In this study, in situ TEM characterization is performed on nanocrystalline nickel samples under self-ion irradiation and post irradiation annealing. During annealing, voids are formed around 200 °C only in the area illuminated by the electron beam. Based on diffraction patterns analyses, it is hypothesized that the electron beam enhanced the growth of a NiO layer resulting in a decrease of vacancy mobility during annealing. The electron beam used to investigate self-ion irradiation ultimately significantly affected the type of defects formed and the final defect microstructure.
Examining the Effects of Independent MALL on Vocabulary Recall and Listening Comprehension: An Exploratory Case Study of Preschool Children
Authors: Terantino Joe
Published: May 2015

In recent years scholars have explored the use of mobile devices as potential sources for language learning and teaching. Mobile phones and tablets, especially, have been researched with a focus on effectively building vocabulary primarily among university-level students. Comparable research in other age groups has not been as widespread. This study examines the nature of preschool-aged children’s use of iPads for independent language learning. In addition, the study identifies the characteristics of the participants’ (n = 7) preferred apps and aims to determine if the participants were able to make gains in vocabulary recall and listening comprehension after a six-month period of independent language learning. The results of this study indicate that the children and their parents established rituals and clear guidelines for playing on the iPad as a means to provide language-learning opportunities. Additionally, they were able to demonstrate moderate gains in vocabulary recall and listening comprehension.
When Ethics and Aesthetics Are One and the Same
Authors: Di Paola Marcello
Published: May 2015

Many environmental philosophers have held naturalness to be a primary source of nature’s value. Seen this way, the nature that is most valuable is wild nature, and ‘wild’ is that which is unmodi?ed by human activity. However, accounts of our attributions of value to the wild often have an aura of elusiveness to them, as if what really matters about nature being wild could not ultimately be captured by words. In an attempt to account for what really matters, I relate our fascination with wild nature to a famous Wittgensteinian quote—‘Ethics and Aesthetics are one and the same’ (Tractatus 2006a: 28, §6.421)—and inspect the ways in which important dimensions of our attributions of value to wild nature can be elucidated by re?ecting on such cryptic identi?cation. I claim that the experience of wild nature more than any other experience forces on us the adoption of what Wittgenstein called the view sub specie aeternitatis (‘through the lens of eternity’) leading us to appreciate the miraculous character of anything being the case at all, ourselves included. Accordingly, the value of wild nature lies in its being a most powerful gesture towards the miracle of existence. The experience of wild nature shows us the good of being alive rather than not. This sort of experience is one in which ethics and aesthetics are one and the same.
Citizens of Planet Earth
Authors: Frisk Kristian
Published: May 2015

The inability of the nation-state system to handle contemporary environmental issues comprehensively has spurred greater cooperation between religious and secular civil society actors. An empirical analysis of the Alliance of Religions and Conservation (ARC) contributes to knowledge about this process on an organizational and identity level. Tracing the mobilization of economic resources shows that the ARC functions as a boundary organization between self-declared religious and secular, local, national, and international actors, while the opening ceremony of the 25th anniversary of the ARC illustrates the identity construction of the organization’s network. This identity is based on a commitment to religious pluralism and a strong emphasis on humanity as an integral part of nature. In conclusion, the ARC is considered as an expression of the rise of what Daniel Deudney (1998) and Bron Taylor (2010a) have termed Terrapolitan Earth Religion.
Religion to the Rescue (?) in an Age of Climate Disruption
Authors: Taylor Bron
Published: May 2015

Since the early 1990s calls by religious elites as well as by scholars who af?liate with and study religions to address the negative consequences of anthropogenic climate change have been increasing. An important example of the trend occurred in November 2014 during the annual meeting of the American Academy of Religion in San Diego where ‘Religion and Climate Change’ was the conference’s central theme. Data presented at this meeting, however, was not encouraging for those hoping that religious individuals were embracing consensus scienti?c understandings about anthropogenic climate change, and becoming deeply concerned about climate disruption and making a strong response to it a high priority. The scienti?c study of the religious dimensions of perceptions and actions related to climate change, for its part, is showing signs of becoming more rigorous and illuminating, better able to track changes that might unfold with regard to religious perceptions and practices related to the earth’s environmental systems.
Scour valve replacement at Digley reservoir
Authors: Tietavainen Marika T
Published: May 2015

Digley reservoir was constructed after the Second World War and completed in 1954. The reservoir has a storage capacity of over three million cubic metres at the top water level. The original pipework arrangement, which included Larner Johnson valves, provided an adequate discharge rate to ensure a minimum of 1·0 m per day drawdown. A statutory inspection of the reservoir was carried out in 2008 in accordance with the Reservoirs Act 1975. Following the inspection, Mott MacDonald Bentley was commissioned by the reservoir owner to undertake works to identify a suitable solution for the scour valve replacement to improve the operability of the valve. The reservoir head of over 40 m and estimated discharge velocity in excess of 10 m/s within the scour pipeline posed limitations to the selection of a suitable valve. The performance of a terminal fixed cone valve retrofitted within the existing stilling basin was modelled as an alternative to an in-line valve replacement. The fixed cone valve has since been installed and it is the first valve of this type for the reservoir owner. This paper describes the valve optioneering process, physical model testing and installation of the fixed cone valve. It also refers to issues working within an operational stilling basin while maintaining provision for the scour facility, and requirements to maintain compensation flow for the duration of the works.
Prevalencia de anomalías dentarias de número en pacientes infantiles y adolescentes de las clínicas odontológicas de la Universidad del Valle desde el 2005 hasta el 2012
Authors: Lagos Daniela , Martínez Ana María , Palacios Jeimy Vanessa , Tovar Daniela , Hernández Jesús Alberto , Jaramillo Adriana
Published: May 2015

Resumen. Introducción: las alteraciones en la formación normal del germen dentaldurante el proceso de odontogénesis, en la dentición decidua o permanente, se denominananomalías dentarias. Estas se clasifican en anomalías de posición, forma,tamaño y número. En este último grupo se incluyen tanto las agenesias dentalescomo los dientes supernumerarios, que se refieren a la ausencia congénita de unoo más dientes y al exceso en la fórmula dental, respectivamente. El objetivo fuedeterminar la prevalencia de anomalías dentales de número en pacientes de 5 a 14años de edad de las clínicas de odontopediatría de la Escuela de Odontología dela Universidad del Valle, en el periodo 2005-2012. Métodos: el diseño del estudiofue descriptivo, de corte transversal. Se analizaron 369 radiografías panorámicasmediante muestreo aleatorio, de un total de 665, usando las historias clínicas comosoporte; con una prevalencia esperada del 4%, un nivel de confianza (ic) del 95% yuna precisión del 2%. Resultados: la prevalencia de anomalías dentarias de númerofue de 4,9% (ic 95%: 2,6-7,1). Las agenesias dentales, excluyendo el tercer molar,fueron más frecuentes, con un 3,8% (ic 95%: 1,8-5,7), sin diferencia significativaentre géneros, en comparación con los dientes supernumerarios que fueron de1,1% (ic 95%: 0,0-2,1) y se presentaron únicamente en hombres. La mayoría de casosfueron en el arco superior. Conclusión: las anomalías de número de este estudiose encuentran dentro del rango reportado en la literatura, con más frecuencia delas agenesias en comparación con los dientes supernumerarios.
Capacity self-assessment as a catalyst for improved municipal service delivery
Authors: van Baalen S , Schutte C , von Leipzig K
Published: May 2015

This research paper illustrates that accurate and truthful capacity assessments are a fundamental phase of any capacity building process, and that capacity assessments play a fundamental role in reaching the necessary performance efficiency. Service delivery performance enhancements by municipalities are becoming increasingly necessary. At the same time, however, the majority of municipalities in South Africa find themselves under-capacitated. Some municipalities are aware of the lack of capacity within their organisation, but are unable to identify, define and quantify these shortcomings. Many other municipalities are not aware of their capacity shortfalls. In both cases, this is often caused by the lack of necessary systems and procedures to assess the different dimensions of organisational capacity. In this regard, this research paper introduces a proposed Subjective Municipal Capacity Self-Assessment Model (SMCSAM) as an alternative solution to the current practices of the Municipal Demarcation Board. It is intended that this model be used internally by municipalities to sustain internal capacity building and performance enhancement initiatives.
Mapping of soil layers using artificial neural network (case study of Babol, northern Iran)
Authors: Choobbasti A , Farrokhzad F , Rahim Mashaie S , Azar P
Published: May 2015

Over the last few years, artificial neural networks (ANNs) have been used successfully for modelling all aspects of geotechnical engineering problems. ANNs are a form of artificial intelligence which attempt to mimic the function of the human brain and nervous system. ANNs are well suited to model the complex behaviour of most geotechnical engineering problems. The purpose of this paper was to assess the layering of subsurface soil using ANNs. Assessing the structure of soil layers on a site, depending on the extent of the study area, requires drilling several boreholes and performing several tests which demand considerable time and money. Increasing the knowledge of soil layer properties between boreholes leads to improved understanding of the near-surface geology. ANNs learn from data examples presented to them in order to capture the subtle functional data relationships, even if the underlying relationships are unknown or the physical meaning is difficult to explain. This paper focuses on the information gathered from the boreholes in a range of 40 square kilometres of Babol City in the north of Iran. The data was collected and classified in order to determine the characteristics of the soil layers. To later classify the different layers at different depths and to determine the thickness of each layer at a specified depth, multi-layer neural networks were trained separately. To quantify the neural network performance in estimating the changes of soil layers, some data from the test boreholes was presented to the network for the first time, and the results of neural networks were compared with actual data obtained from site investigations. The results show a high degree of accuracy in prediction by ANN models.
Genetic polymorphisms of ADH1B, ADH1C and ALDH2 in Turkish alcoholics: lack of association with alcoholism and alcoholic cirrhosis
Authors: Vatansever Sezgin , Tekin Fatih , Salman Esin , Altintoprak Ender , Coskunol Hakan , Akarca Ulus Salih
Published: May 2015

No data exists regarding the alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) gene polymorphisms in Turkish alcoholic cirrhotics. We studied the polymorphisms of ADH1B, ADH1C and ALDH2 genes in alcoholic cirrhotics and compared the results with non-cirrhotic alcoholics and healthy volunteers. Overall, 237 subjects were included for the study: 156 alcoholic patients (78 cirrhotics, 78 non-cirrhotic alcoholics) and 81 healthy volunteers. Three different single-nucleotide-polymorphism genotyping methods were used. ADH1C genotyping was performed using a polymerase chain reaction-restriction fragment length polymorphism method. The identified ADH1C genotypes were named according to the presence or absence of the enzyme restriction sites. ADH1B (Arg47Hys) genotyping was performed using the allele specific primer extension method, and ALDH2 (Glu487Lys) genotyping was performed by a multiplex polymerase chain reaction using two allele-specific primer pairs. For ADH1B, the frequency of allele *1 in the cirrhotics, non-cirrhotic alcoholics and healthy volunteers was 97.4%, 94.9% and 99.4%, respectively. For ADH1C, the frequency of allele *1 in the cirrhotics, non-cirrhotic alcoholics and healthy volunteers was 47%, 36.3% and 45%, respectively. There was no statistical difference between the groups for ADH1B and ADH1C (p>0.05). All alcoholic and non-alcoholic subjects (100%) had the allele *1 for ALDH2. The obtained results for ADH1B, ADH1C, and ALDH gene polymorphisms in the present study are similar to the results of Caucasian studies. ADH1B and ADH1C genetic variations are not related to the development of alcoholism or susceptibility to alcoholic cirrhosis. ALDH2 gene has no genetic variation in the Turkish population.
Comparison of Hemoglobin A1c assay performance on two different commercial systems
Authors: Ćorić Jozo , Kučukalić Elma , Hasanefendic Berina , Bodulović Aleksandar , Mujic Jasminka , Panjeta Mirsad
Published: May 2015

Introduction: Glycated hemoglobin (HbA1c) is formed by non-enzymatic binding of glucose to the free amino group of the N-terminal end of the ß-chain of hemoglobin A. HbA1c is representative of the mean blood glucose level over three months. The aim of the study was to evaluate the Hemoglobin A1c immunoturbidimetric assay performance on two different commercial systems.Methods: We evaluated the precision and trueness for determination of HbA1c in whole blood. Concentrations of total hemoglobin and HbA1c were evaluated on Dimension Xpand (Siemens) and Cobas 501 (Roche) analyzers. HbA1c was measured in a latex agglutination inhibition test. Commercial controls Liquichek Diabetes Control Level 1 and Liquichek Diabetes Control Level 2 (Bio Rad) at two levels were used for quality control. Analytical validation of HbA1c included: within-run imprecision, between-day imprecision, inaccuracy and comparison determination on the human samples on 2 systems: Dimension Xpand and Cobas 501 analyzers. Results: Within-run imprecision on the commercially controls for Level 1 is 4.5% and Level 2 is 3.2% between-day imprecision on commercially controls is 6.1% Level 1 and 5.1% Level 2 for respectively inac- curacy on commercially controls for Level 1 is 1.8% and Level 2 is 4.8%. Method comparison on human samples shows the correlation coefficient of 0.99.Conclusion: The presented results of the analytical evaluation methods for the determination of HbA1c showed an acceptable accuracy and precision.
Salamander growth rates increase along an experimental stream phosphorus gradient
Authors: Bumpers Phillip M. , Maerz John C. , Rosemond Amy D. , Benstead Jonathan P.
Published: May 2015

Nutrient‐driven perturbations to the resource base of food webs are predicted to attenuate with trophic distance, so it is unclear whether higher‐level consumers will generally respond to anthropogenic nutrient loading. Few studies have tested whether nutrient (specifically, nitrogen [N] and phosphorus [P]) enrichment of aquatic ecosystems propagates through multiple trophic levels to affect predators, or whether N vs. P is relatively more important in driving effects on food webs. We conducted two‐year whole‐stream N and P additions to five streams to generate gradients in N and P concentration and N:P ratio (target N:P = 2, 8, 16, 32, 128). Larval salamanders are vertebrate predators of primary and secondary macroinvertebrate consumers in many heterotrophic headwater streams in which the basal resources are detritus and associated microorganisms. We determined the effects of N and P on the growth rates of caged and free‐roaming larval Desmognathus quadramaculatus and the average body size of larval Eurycea wilderae. Growth rates and average body size increased by up to 40% and 60%, respectively, with P concentration and were negatively related to N:P ratio. These findings were consistent across both species of salamanders using different methodologies (cage vs. free‐roaming) and at different temporal scales (3 months vs. 2 yr). Nitrogen concentration was not significantly related to increased growth rate or body size of the salamander species tested. Our findings suggest that salamander growth responds to the relaxation of ecosystem‐level P limitation and that moderate P enrichment can have relatively large effects on vertebrate predators in detritus‐based food webs.
The Impact of Increased Skin-to-Skin Contact With the Mother in Breastfeeding Neonates on Exclusive Breastfeeding at 4 and 8 Weeks Postpartum
Authors: Ruxer Deborah J. , Brewer Tracy , Mateer Karen , Burkhardt Melissa , Shay Mary
Published: May 2015

Objective: To evaluate dose of skin-to-skin (STS) contact as a nursing intervention to increase the rate of exclusive breastfeeding after discharge

Design: A descriptive correlational study

Setting: A Level II maternity unit in Ohio

Participants:
Women who had a vaginal delivery of a term, well newborn, with intent to exclusively breastfeed

Methods: Newborns were placed STS with their mothers at birth. Mothers were encouraged to maintain frequent STS with their newborns while in the hospital, and kept a log of STS time.
A lactation consultant made follow-up phone calls at 4 weeks and 8 weeks postpartum to assess breastfeeding exclusivity. Spearman rho was used to analyze the data.

Results: Duration of STS was not correlated with exclusive breastfeeding at either 4 weeks or 8 weeks postpartum. However,
early STS was correlated with exclusive breastfeeding at 4 weeks postpartum.
A General Method for the Selection of an Optimum Choke Management Strategy
Authors: Karantinos Emmanouil , Sharma Mukul M. , Ayoub Joseph A. , Parlar Mehmet , Chanpura Rajesh A.
Published: May 2015

Different choke management strategies have been adopted by operators in the field. However, no general method exists for systematically selecting an optimum choke management strategy. In this study, we propose a general method for the selection of bean-up duration and bean-up strategy (choke management), that will maximize well productivity by minimizing formation damage, reducing sand production and reducing the impact of multiphase flow effects.

Strategies of stepwise bottom-hole pressure (BHP) adjustments are compared using the principle of superposition and the analytical solution of the diffusivity equation for vertical wells operating under different choke settings. The optimum choke management strategy is based on the anticipated formation damage mechanisms. For example, if fines migration and sand production are a concern, then minimizing the near wellbore pressure gradients is the primary criterion for the selection of the optimum choke management strategy.

Results indicate that the selection of the optimum strategy (sequence of choke settings) is independent of the drawdown and depends primarily on the duration of the ramp-up period. Among the 251 strategies evaluated, three of them consistently appear to be the optimum. We further refine strategies using a single parameter, incorporated in a dimensionless expression of BHP as a function of time. From simulation results, we conclude that for relatively short bean-up durations (i.e., infinite acting behavior), the pressure gradient reduction at the wellbore varies logarithmically with time. Choke management strategies appear to have similar performance as far as no more than 70% of the drawdown is applied during the initial 20% of the overall bean-up duration. For longer durations (i.e., when the presence of the no-flow boundary is felt), the optimum strategy depends on both reservoir properties and radial extent. For the case of square drainage area, a plot suggesting the optimum strategy with respect to dimensionless duration is presented. Positive skin and multiphase flow near the wellbore, negatively affect the performance of bean-up strategies. For vertical wells producing from multiple layers, bean-up strategies should be selected with respect to the effective horizontal permeability, ultimately yielding the greatest pressure gradient reduction in the low permeability zones.

The proposed method enables engineers to select the optimum choke management strategy with respect to bean-up duration and formation properties. The duration of the bean-up process is drawdown dependent thus further research is encouraged in determining the maximum allowable pressure gradient in order to curtail sand production.
Thermal Decomposition Effects on Perforating Performance and Safety
Authors: Boock A. E. , Brinsden M. S. , Sokolove C. , Golian T. G. , Maienschein J. L. , Glascoe E. A.
Published: May 2015

Explosive thermal stability is an important topic for oilfield perforating operations and impacts perforating system performance and safety. Explosives have time dependent temperature limits which can lead to thermal decomposition when exceeded and, under some circumstances, can result in performance losses and safety hazards. Explosive thermal stability information is currently provided by perforating system manufacturers through time versus temperature plots. While these plots have proved useful for many years, this review of current industry thermal stability data and practices aims to highlight a need for improvement and expanded testing representative of the energetic materials as used in actual well environments.

More specifically, this review discusses the potential economic impact on well performance and operational safety when thermal stability limits are exceeded. When using currently available time versus temperature plots, operators sometimes must select lower performing explosives which are thermally stable at higher temperatures especially for high temperature well environments. As a result, operators risk optimal well inflow performance with significant economic impact. Furthermore, exceeding the time dependent temperature limits can lead to thermal decomposition. Off-gassing from thermal decomposition can trap pressure inside of gun carriers creating safety hazards during misruns. This review includes a reference to a known occurrence where overexposure to temperature led to thermal runaway and a surface explosion of a recovered perforating system.

Additionally, this review discusses shortcomings in thermal stability test methods and related API recommended practices. Current methods assessing thermal stability, including vacuum thermal stability, ampule, and ODTX (One Dimensional Time to Explosion) tests tend to use unrealistic test conditions. The API recommended practices do not directly assess thermal decomposition which is important in developing safe practices for recovered perforating systems which may have been exposed to temperatures exceeding thermal stability limits.

This review concludes with recommendations for future work to better understand thermal stability in oilfield explosives. More suitable thermal stability tests which evaluate oilfield explosives in well environment conditions will lead to improved safety recommendations and has the potential for significant economic impact on well productivity through enhanced understanding of the time dependent temperature limits. Finally, this paper draws on the urgent requirements of the Operator community, the experience of the manufacturing community and the advanced technical support of a US National Laboratory to provide a concise review and recommendations which can then be promulgated through the API, as a major step in enhancing safety and ultimately well performance.
A New Class of Associative Polymer for Hydraulic Fracturing Applications
Authors: Cadix A. , Wilson J. , Carouhy T. , Harrisson S. , Guichon H.
Published: May 2015

Fluids used in stimulation are designed to open fractures and transport proppant along the length of the fracture. As a consequence, the rheological behavior of that fluid is very carefully designed. Throughout the past years many systems have been developed to achieve a subtle balance of properties in which the fluid initially develops a specified viscosity in the fracture, followed by rapid fluid rheology breaking and fracture cleanup at the end of the operation. In addition, a good fluid loss control is of key importance for treatment efficiency as well as for the prevention of formation damage. Current grades of derivatized guars show improved cleanup versus native guars but are still not fully satisfactory. In addition, polymer free systems based on viscoelastic surfactants (VES) have raised considerable interest due to their ease of cleanup leaving no residues in the fractures. Nevertheless, these systems still need high active concentrations to develop rheology at elevated temperature and in hard water conditions.

Alternative systems based on synthetic polymers have shown increasing interest over the past years for Oil and Gas applications but their utilization as rheology modifiers in stimulation fluids are still limited. Most of their application is in polymer flooding (EOR) or friction reduction.

Associative polymers based on polyacrylamide derivatives can demonstrate dramatically enhanced rheological performance over standard hydrophilic polymers. Hydrophobic associations behave like crosslinking points providing improved Proppant suspension. These crosslinking points are physical associations and can easily be disrupted just like VES with dilution or in the presence of hydrocarbons or surfactants and leave little to no residues in a Proppant pack.

In order to meet challenging Oil and Gas rheological performance targets focusing on high temperature efficiency, associative polymers are here prepared using the Micellar polymerization process. This process consists of the aqueous polymerization of hydrophilic monomers in presence of micelles containing hydrophobic monomers and yields hydrophilic polymers bearing a small amount of hydrophobic groups with multiple hydrophobic monomers per group. The amounts of groups as well as the number of hydrophobes per group are can be tuned to meet rheology targets. In addition, coupling this process with a controlled radical polymerization technique affords associative polymers of significantly higher performance through the reduction of chain to chain compositional heterogeneities which are known to be a significant limitation of the Micellar polymerization process.

The present study demonstrates that primary rheological performance can be met up to very high temperatures using this unique process. In addition, fluid-loss control data as well as a preliminary assessment of cleanup are presented and discussed versus classical gelling systems.
Early Detection of Gas Well Formation Damage, Water Breakthrough and Liquid Loading by Use of Surface Pressure Build-Up Data
Authors: Veeken C. A. , Mittal Anurag , Bertsché Stijn
Published: May 2015

Gas well performance can deteriorate or improve as a result of changes in inflow and outflow. Early detection of such changes allows timely recognition of their impact on the production forecast and, if necessary and justified, timely execution of remedial activities. This article will demonstrate how comparison of subsequent surface pressure build-up (S-PBU) periods reveals either onset of formation water production and/or liquid loading and that can be use to estimate WGR. The S-PBU data can also be transformed into a dynamic inflow performance relation (D-IPR). It will be demonstrated how the evolution of this D-IPR reflects changes in inflow performance either due to impairment or due to stimulation. In addition, the D-IPR provides an independent measure of the gas production rate prior to shut-in. And best of all, this data is abundant, typically free of charge and easily digestible.
A Case Study of Modelling Squeeze Treatments in a Fractured Formation
Authors: Spooner Victoria , Stalker Robert , Graham Gordon M , Cook Stuart , Haugen Chris , Lu Haiping
Published: May 2015

Scale inhibitor squeeze treatments in unfractured reservoirs can be readily simulated in matrix flow models, designing such treatments for application in fractured reservoirs is less routine. One reason for this is that the flow process and transport mechanisms by which the inhibitors are retained in fractured formations differ considerably from simple matrix flow. In previous papers, we described a diffusion-controlled transport model for scale inhibitors in low permeability fractured reservoirs where little matrix flow is expected. In this paper, the model has been used to simulate squeeze treatments performed on multiple wells in a fractured shale formation and compared to simulations using a matrix flow model.

A number of squeeze treatments were performed on wells in a fractured shale formation yielding long treatment lifetimes. The squeeze treatments were designed using a matrix flow model. Calculations indicated the design pumping rate would require an injection pressure significantly more than the fracture pressure for the formation indicating little matrix may possible for this case. The treatments were successful, however, the observed field return did not match the prediction and in some cases longer treatment lifetimes were observed.

When a standard matrix flow model was used, the resulting field isotherms were significantly different for each well in the formation. This is taken to indicate that the matrix flow model approach is not accurately mimicking the field data. When the same data was examined using the diffusion based fracture model, a single isotherm was found to be a good match for all of the wells from the formation. In addition, explicitly modelling the varying water production rates in the diffusion model gave good correlation with changing trends in the return concentrations seen in the field return. Furthermore the possibility of improving the treatment lifetime is considered, factors such as the effect of the overflush volume and injection rate are discussed as treatment modifications and the influence may have on formation damage.

Accurate prediction of squeeze treatment lifetimes is important for scale management both economically to ensure optimum productivity and practically to schedule treatments appropriately. Until recently this has not been achievable for fractured formations without the use of full field simulators. The paper illustrates that an appropriate near wellbore model can give good agreement with field data and has been used to design better treatments without the need for complex full field simulators.
Mitigation of Formation Damage and Wellbore Instability in Unconventional Reservoirs Using Improved Particle Size Analysis and Design of Drilling Fluids
Authors: Dorman J. , Lakatos I. J. , Szentes G. , Meidl A.
Published: May 2015

The key to formation damage control is minimizing the depth of contact/impact of the formation and drilling fluid by minimizing solids and liquid invasion into porous (fractured) formations. Analysis of downhole filtration conditions and particle size (distribution) measurements were used to select “fit to pore size” fluid loss control materials in order to maximize pore/fracture plugging efficiency. Further tests served to predict potential alteration of rock properties. Particle size measurements have been performed for commonly used (natural and synthetic) polymeric fluid loss and other additives dispersed in water. High-pressure Hg porosimetry was used to determine the pore size distribution of core samples. Core flow tests served to measure permeability and permeability damage caused by fluid loss additives. Spontaneous fluid absorption rate was studied using modified tensiometer and wettability of the cores were determined by ‘sitting drop’ technique.

In low permeability porous (tight and shale gas) formations consisting of macro to nano pores most filtration studies are limited to provide reliable filtration data for all cases due to the fact that drilling fluids solids particle sizes relative to pore sizes. Particle size measurements of commonly used (natural and synthetic) polymeric fluid loss additives in water have provided typical size range by particle number in the 25-35 nm range, and 120-700 nm by volume. Such particles can play a significant role in internal plugging of micro to nano size pores and microfractures. Core flow/filtration tests using low permeability (<5 mD) core samples and model fluids containing fluid loss additives resulted in rapid permeability reduction (to 100%), typically in close to core face region. Results proved the achievable pore plugging efficiency and invasion control into low permeability rocks during drilling. Particle size data gained for CPG (Cloud Point Glycol) solutions proved that this system could also be used to form efficient barrier within the low permeability formation, showing certain analogy between mitigation of formation damage and wellbore instability. Better insight into downhole filtration mechanism and conditions, especially for initial filtration phase in low permeability formations can lead to designed “shallow bed” instead of practically uncontrolled “deep bed” filtration, where external filter cake is essentially not formed. Such internal pore plugging technique can be the key to the minimization of solids/liquid invasion and associated formation damage.
Unique Application of an Inhibitor to Mitigate Scale between Formation Water and Divalent-Base Drilling and Completion Fluids
Authors: Allogo C. M. , Ravitz R. , Nguyen C.
Published: May 2015

An operator in Gulf of Guinea experienced dramatic production impairment due to calcium carbonate scaling. Post completion analysis revealed that the scaling magnitude was dependent upon several influences, primarily the reservoir pressure; access to mobile formation water coupled with its scaling tendency induced carbonate scales deposit. The impact of the completion brine and drilling mud and filtrate as whole losses or secondary filtrate were identified as contributors. The above study and its conclusions were reported concurrent with on-going planning for the next horizontal drill and open-hole gravel-pack completion. The water-base reservoir drilling fluid (RDF), screen running fluid (SF), completion brine, gravel pack carrier fluid, and filter-cake breaker fluid were designed with divalent calcium chloride brine. The required products for these systems were already on location and operations very close to commencing.

Redesigning all these systems by replacing the divalent brine with monovalent brine would require additional resources and delay the project. However, a scale inhibitor was recommended to mitigate the initial risk of scale formation when using divalent calcium brine. Concentrations of Scale inhibitors were tested over a range of temperature from 150F to 250F, and ratios between formation water and selected fluids from 25/75 to 75/25. Testing considered adding a scale inhibitor to the RDF as well as the other required systems.

This upfront assessment indicated that the selected inhibitor prevented scaling with formation water. As such, the operator approved the use of the scale inhibitor and the well was successfully drilled and completed. Higher initial production than modeled was realized for this well compared to other wells in this field.

This paper will present the upfront testing to assess shale inhibitor efficiency, results, and the field application used to reduce the risk of formation damage during the drilling and completion phases.