bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving microbial fitness in the mammalian gut by in vivo temporal functional metagenomics
Authors: Yaung Stephanie J , Deng Luxue , Li Ning , Braff Jonathan L , Church George M , Bry Lynn , Wang Harris H , Gerber Georg K
Published: March 2015

Elucidating functions of commensal microbial genes in the mammalian gut is challenging because many commensals are recalcitrant to laboratory cultivation and genetic manipulation. We present Temporal FUnctional Metagenomics sequencing (TFUMseq), a platform to functionally mine bacterial genomes for genes that contribute to fitness of commensal bacteria in vivo. Our approach uses metagenomic DNA to construct large‐scale heterologous expression libraries that are tracked over time in vivo by deep sequencing and computational methods. To demonstrate our approach, we built a TFUMseq plasmid library using the gut commensal Bacteroides thetaiotaomicron (Bt) and introduced Escherichia coli carrying this library into germfree mice. Population dynamics of library clones revealed Bt genes conferring significant fitness advantages in E. coli over time, including carbohydrate utilization genes, with a Bt galactokinase central to early colonization, and subsequent dominance by a Bt glycoside hydrolase enabling sucrose metabolism coupled with co‐evolution of the plasmid library and E. coli genome driving increased galactose utilization. Our findings highlight the utility of functional metagenomics for engineering commensal bacteria with improved properties, including expanded colonization capabilities in vivo.
Стан імунограми пацієнтів, позитивних у люпус-тесті
Authors: Voronkova O. S. , Voronina N. O. , Polishko T. M. , Vinnikov A. I.
Published: March 2015

Розглянуто зміни показників імунного статусу пацієнтів, позитивних за люпус-тестом. Охарактеризовано експресію деяких рецепторів на поверхні лімфоцитів периферійної крові. Розраховано кореляцію для показників тесту відновлення тетразолію нітросинього та рівня експресії CD95-рецептора (рецептора апоптозу).
Биосинтетические характеристики мутантного штамма Streptomyces recifensis var. lyticus 2р-15 в присутствии экзогенных аминокислот
Authors: Zhernosekova I. V. , Tymchuk А. А. , Ponizovtseva А. G. , Chernogor N. P. , Vinnikov A. I.
Published: March 2015

Досліджено дію екзогенних амінокислот на прояв біосинтетичної активності рифампіциностійкого штаму 2Р-15. Показано, що амінокислоти в оптимальних концентраціях (50, 100, 200 мкг/мл) викликають максимальне збільшення синтезу білка, накопичення біомаси, активності стафілолітичних ферментів і продуктивності стрептоміцету в умовах глибинної ферментації. Усі досліджені амінокислоти забезпечили підвищення стимулювальної активності штаму в 2,0–3,7 раза.
Роль осиково-березових колків у збереженні різноманіття ґрунтів і безхребетних тварин степової зони України
Authors: Loza I. M. , Brygadyrenko V. V.
Published: March 2015

Наведено приклад комплексного підходу до досліджень екологічних особливостей існування острівних лісів (колків) у степовій зоні України. Охарактеризовано основні шляхи ґрунтоутворення, видовий склад флори. Проаналізовано особливості формування герпетобію пісків у мезогігрофільних і гігрофільних умовах другої тераси долини ріки Самари.
Влияние индивидуальности кормового растения на изменчивость приспособительно важных признаков зеленой дубовой листовертки и ее взаимодействие с паразитами
Authors: Simchuk A. P. , Ivashov A. V. , Savushkina I. G.
Published: March 2015

Досліджено вплив індивідуальності кормової рослини дуба пухнастого (Quercus pubescens Willd.) на мінливість адаптивно важливих ознак у генотипічних класах особин зеленої дубової листовійки (Tortrіx vіrіdana L.) і на її взаємодію з паразитами. Внесок взаємодії факторів, що характеризують індивідуальність кормової рослини та генетики зеленої дубової листовійки, у мінливість адаптивно важливих ознак складає 22 % у самців і 42 % у самиць. Вибір паразитом Itoplectis maculator F. особин листовійки залежить від їхніх розмірів. Індивідуальні особливості кормової рослини визначають характер селективності цього вибору відносно генотипів листовійки.
Питання водного режиму рослин у працях вітчизняних фітофізіологів: історично-функціональний аспект
Authors: Khristova T. E. , Pyurko O. E.
Published: March 2015

В історично-функціональному аспекті показано досягнення вчених України у розробці водного режиму рослин. Вітчизняні дослідники внесли суттєвий вклад у розвиток різних напрямків даної проблеми: створення та вдосконалення матеріально-технічної бази; розробки та використання сучасних методів вивчення водного режиму рослин; отримання надійної інформації у теоретичному та практичному контекстах.
Nicolás Maquiavelo un amoral con elementos morales, un acercamiento a su pensamiento desde la ética
Authors: Miranda Fonseca Héctor Eduardo
Published: March 2015

El presente trabajo intenta explicar las grandes líneas del pensamiento de Nicolás Maquiavelo, con el fin de establecer su pensamiento amoral y como a través de categorías de análisis intenta  explicar su pensamiento alrededor de la política y del reconocimiento del nuevo escenario en Europa, que se comienza a perfilar con la aparición del Estado Moderno y se quiere enmarcar este acercamiento teórico,  con el fin de descubrir como en ese pensamiento, en forma larvada se encuentran elementos éticos, que no se descubren en su propio pensamiento, sino en su comportamiento como persona, y por el momento histórico que le toca vivir en Italia.
Virtud en La República de Platón y El Príncipe de Maquiavelo
Authors: Masís Iverson Katherine
Published: March 2015

Desde el punto de vista de la ética de virtudes, el presente ensayo compara los filósofos-reyes de Platón con el príncipe de Maquiavelo. Primeramente, se define la ética de virtudes; seguidamente, se explica la manera en que se manifiesta la virtud en La República de Platón y El Príncipe de Maquiavelo. Finalmente, se valoran las semejanzas y diferencias entre ambos autores con respecto al concepto de virtud.
Wpływ reformy emerytalnej na deficyt sektora instytucji rządowych i samorządowych
Authors: Ancyparowicz Grażyna
Published: March 2015

The social security reforms implemented against the background of deep imbalances in the labour market have generated a huge public debt, whose interest burden has been absorbing a growing part of state budget revenues. To reduce these expenses, some of the government’s tasks were transferred to local government. But in the absence of adequate financial resources this led to a sharp increase in debt in the local government sector. In 2009, the structural shortage of the general government budget was so large that the European Commission implemented an excessive deficit procedure against Poland, which remains in force. The reform of the open pension funds and other points of the fiscal consolidation program carry the promise that the budget target will be achieved in 2015. In the longer term, though, we should strive to increase inflows to the Social Insurance Fund instead of lowering the purchasing power of social security benefits.
Wpływ kryzysu finansowego na politykę podatkową Republiki Irlandii
Authors: Niżnik Joanna
Published: March 2015

The aim of this paper is to present and evaluate the changes introduced by the Irish government in the tax system and their influence on tax revenues. The first part offers a brief summary of the overall structure of the state tax system, identifying elements of tax construction and the changes caused by the financial crisis. The second part focuses on the major changes in personal income tax and capital taxes, which entailed raising the tax rate, the reduction and abolition of tax relief and the introduction of new taxes, such as a levy on financial institutions and the domicile levy. The other taxes have hardly been modified but their share of, and influence on, tax revenue is less significant.
Prevalência de sibilância e fatores associados em crianças indígenas Guarani hospitalizadas por doença respiratória aguda no Sul e Sudeste do Brasil
Authors: Souza Patrícia Gomes de , Cardoso Andrey Moreira , Sant’Anna Clemax Couto
Published: March 2015

Realizou-se estudo de prevalência de sibilância em crianças indígenas Guarani hospitalizadas por infecção respiratória aguda baixa no Sul e Sudeste do Brasil, recrutadas a partir de um sistema de vigilância implantado nas aldeias entre maio de 2007 e junho de 2008. Os dados foram extraídos por revisão dos prontuários hospitalares. Estimaram-se razões de prevalência de sibilância brutas e ajustadas segundo categorias das variáveis exploratórias, por regressão de Poisson com ajuste para variância robusta. A prevalência de sibilância foi de 58,1% (136/234). Permaneceram significativamente associadas à sibilância no modelo final: faixa etária, inversamente associada (0-11 meses: referência; 24-35 meses: 0,63, IC95%: 0,40-0,99); internação no outono (verão: referência; outono: 1,58, IC95%: 1,05-2,40); e sinais clínicos de dispneia (1,41, IC95%: 1,09-1,83), tiragem (1,42, IC95%: 1,16-1,73) e estertor (1,43, IC95%: 1,09-1,87). Os resultados revelam elevada carga de morbidade por sibilância e sugerem o fenótipo de sibilância persistente de início precoce, relacionada à recorrência de infecções respiratórias virais.
Como dar suporte às estratégias de empresas hoteleiras? Uma análise segundo a visão baseada em recursos
Authors: Santos Luciano Costa , Gohr Cláudia Fabiana , Cruz Igor Kenji Hilahata , Cunha Hítalo Silva
Published: March 2015

A visão baseada em recursos destaca o papel dos recursos empresariais para a eficácia das estratégias e para a construção de uma vantagem competitiva sustentável. Com base nesses conceitos, este artigo tem por objetivo verificar se os recursos estratégicos de duas empresas do setor hoteleiro de um município do estado de Mato Grosso do Sul estão contribuindo para as estratégias realizadas por essas organizações e, consequentemente, para sua vantagem competitiva. Para alcançar esse objetivo, foi adotado o método do estudo de caso, utilizando como técnica principal de coleta de dados a entrevista semiestruturada com perguntas abertas e fechadas dirigidas aos gerentes das empresas. Os resultados demonstraram um padrão comum entre as empresas pesquisadas, que apresentaram estratégias e recursos semelhantes. A avaliação dos recursos estratégicos permitiu entender a sua contribuição e a relação deles com as estratégias identificadas para os dois hotéis.
Melhoria da eficiência energética em sistemas motrizes industriais
Authors: Sola Antonio Vanderley Herrero , Mota Caroline Maria de Miranda
Published: March 2015

A comunidade científica internacional tem considerado o uso eficiente de energia em sistemas de produção extremamente importante para o desenvolvimento sustentável. Este artigo estuda a melhoria da eficiência energética em sistemas motrizes industriais por meio de mudança tecnológica. Inicialmente é feita uma revisão de literatura para apresentar as principais ações e barreiras para a melhoria da eficiência energética em sistemas industriais de energia e também destacar o uso de uma abordagem multicritério em caso de mudança tecnológica. O artigo apresenta um estudo de caso em uma indústria com o objetivo de ordenar motores elétricos para serem substituídos utilizando o método multicritério PROMETHEE II. O estudo revela que a escolha dos critérios pode alterar a ordem de prioridade de escolha das tecnologias a serem substituídas, com impacto no desempenho das novas tecnologias. O artigo enfatiza a importância da integração de todas as áreas da empresa para que sejam atendidos os interesses da organização.
Resistance gradient of black pod disease in cocoa and selection by leaf disk assay
Authors: Santos Elisa Susilene Lisboa dos , Cerqueira-Silva Carlos Bernard Moreno , Clement Didier , Luz Edna Dora Martins Newman
Published: March 2015

To characterize the gradient of resistance to black pod disease experimentally, the leaf disk assay was applied to 217 cocoa genotypes. The parameters time interval, number of leaves evaluated per genotype and distribution of experimental treatments were evaluated. Significant differences between genotypes were found, resulting in the grouping in five homogenous groups (p < 0.01). In the assessments with the leaf disk test, five and seven days after inoculation, the F value was highest after seven days, clearly separating the resistant from susceptible genotypes. There was no difference between the clones behavior and the use of more than one box to group the genotypes (p = 0.56) and the use of different leaves of the same genotype (p = 0.08). The resistance gradient observed indicates variability enough for mapping and cocoa breeding in the population.
ISSR markers for genetic relationships in Caricaceae and sex differentiation in papaya
Authors: Costa Fabiane Rabelo da , Pereira Telma Nair Santana , Gabriel Ana Paula Candido , Pereira Messias Gonzaga
Published: March 2015

ISSR markers are polymorphic and their results easily reproducible. They are therefore intensely used in phylogenetic studies and sex differentiation of some economically interesting plant species. The objectives of this study were to analyze the genetic diversity in Caricaceae using ISSR markers, to identify a specific ISSR band that could distinguish female from hermaphrodite papaya genotypes and to verify whether this marker could be used for early sex differentiation. The ISSR-PCR was performed with nine primers and they could distinguish all species. It was observed that Jacaratia spinosa was closer to Vasconcellea than to Carica. The species C. papaya was only distantly related to both genera. A 500 bp ISSR marker was found in 25 % of the papaya genotypes studied. Specifically in these cases this marker could be used for early sex differentiation in papaya.
CD 120 wheat cultivar, standard quality soft, for the Southern Region of Brazil
Authors: Marchioro Volmir Sergio , Franco Francisco de Assis , Nora Tatiane Dalla , Oliveira Edson Feliciano de , Schuster Ivan , Evangelista Adriel , Rocha Renato da , Polo Mateus
Published: March 2015

The cultivar CD 120, developed by the Cooperativa Central de Pesquisa Agrícola (COODETEC) is suitable for cultivation in the VCU wheat-producing regions 1 and 2 of the states of Paraná, Santa Catarina and Rio Grande do Sul. It is tolerant to the major wheat diseases and pre-harvest germination and has soft wheat quality and a 6.5 % higher grain yield (3.678 kg ha-1) than the control.
Interface entre o religioso e o político: o Golpe Civil-Militar de 1964 e a Igreja Presbiteriana do Brasil
Authors: Vilela Márcio Ananias
Published: March 2015

O presente artigo versa sobre o comportamento de um relevante segmento protestante, a Igreja Presbiteriana do Brasil, frente ao Golpe civil-militar de 1964. Na produção desta análise, foram analisados diversos documentos institucionais, assim como diferentes jornais impressos, possibilitando mapear algumas relações estabelecidas naquele momento com o Estado, onde aspectos religiosos e políticos se entrecruzam. A narrativa presente neste artigo contribui para a compreensão do emblemático cenário de embates entre diferentes projetos de sociedade, marcando a construção social da ditadura brasileira pós 1964.
O PAPEL DA EDUCAÇÃO AMBIENTAL NO ESTUDO DAS FONTES RENOVÁVEIS DE ENERGIA NAS ESCOLAS BRASILEIRAS
Authors: Wrobel Fernanda Campos Maia
Published: March 2015

Resumo: Este artigo analisou a importância da implementação do estudo dos recursos naturais renováveis, como fonte alternativa de energia, nas escolas brasileiras, através da Educação Ambiental. Discutiu-se como a Educação Ambiental pode alterar padrões de comportamentos, e ser vista como degrau para a valorização do meio ambiente, tendo em vista a conexão entre uso da energia e danos ao meio ambiente. Analisou os conceitos e vantagens da utilização dos recursos naturais renováveis e como a educação ambiental surge como agente formador da cidadania ecológica, na medida em que, identifica a importância e a necessidade da utilização desses recursos naturais renováveis como uma nova forma de se pensar o planeta. Analisou o tema educação ambiental sob o ponto de vista do discurso ecológico oficial e o alternativo, bem como as dificuldades de se efetivar o discurso ecológico alternativo dentro do ambiente escolar. Demonstrou como a educação ambiental deve transcender os limites da escola, indo além do currículo, do método e dos anseios do mercado, e atingir todo o espaço social. Considerou a Educação Ambiental como um instrumento formal e informal de educação na busca de se atingir a sustentabilidade. Analisou, também, as formas de se implementar o uso das fontes energéticas renováveis. A metodologia utilizada foi a pesquisa bibliográfica de cunho qualitativo, alicerçada em doutrina, artigos científicos, pesquisas relacionada ao tema. O marco teórico é a Lei de Política Nacional de Educação Ambiental, sob o nº 9.795/99, devendo estar presente em todos os níveis e modalidades do processo educativo nacional, trazendo a permanente avaliação crítica, a adequação dos conteúdos à realidade local e o envolvimentos dos atores em ações concretas para transformação de uma realidade.
REGULATION AND SELF-REGULATION OF INSURANCE ACTIVITY
Authors: Nasyrova G. A.
Published: March 2015

The article examines other countries’ experience in developing methods and types of regulating insurance activity. Aims, tasks and mechanisms of self-regulation in this field are rationalized. Negative aspects of self-regulation are revealed. In the author’s opinion, a balanced combination of state regulation, self-regulation and co-regulation is needed for increasing socio-economic efficiency of insurance activity.
EFFICIENCY ANALYSIS OF BRANCH AND DIVISION ACTIVITIES IS A PREREQUISITE FOR BUSINESS STABILITY
Authors: Kryukov A. M.
Published: March 2015

The article overviews business development strategies aimed at extending branch and division net. To provide stability in such social and economical systems of complicated structure it is essential to create mechanisms of self-regulation based on complex evaluation of structural unit activities. The article rationalizes evaluation methods in short- and long-term periods of branch net creation. A system of key efficiency indicators, allowing to perform branch activity monitoring and react to changes timely, is presented.
The Influence of Inlet Pressure Control on Separation Performance of
Multi-Product Cyclones
Authors: Liu Tingrui , Liu Peikun , Wang Zengyin , Yu Ziqing
Published: March 2015

This paper is devoted and intended to solve the problems in determining the precise separation efficiency and
accurate prediction for the solid yield of multi-product cyclones based on existing experimental data. The influence of
inlet pressure control on separation performance of multi-product cyclones is investigated. Hydrocyclone separation
performance is influenced by many factors such as the liquid level of agitating vessel and the entrance pressure. The
liquid level can also be controlled through the entrance pressure control. The mathematical model of multi-product
cyclone system is a high-order complex model and it is difficult to determine the specific expressions. The paper adopts a
special optimal fuzzy PI_PID control strategy performed by Programmable Logic Controller system to enable inlet
pressure control. By the force of contrast with experiment and analysis for many performance indexes, the effectiveness
and applicability of the control approach are demonstrated. The research provides a method for control of high-order
complex system of hydrocyclone separation.
Relationship Between Japan’s Renewable Energy Generating Capacity
and Economic Growth Based on ARDL Model
Authors: Na Ming , Li Ying , Li Kang
Published: March 2015

Under the background of the global energy shortage and Japan's Fukushima nuclear spill, Japan is faced with
an important choice whether to abandon nuclear power or develop renewable energy. This paper used autoregressive
distributed lag model to do the empirical analysis of the relationship between renewable energy generating capacity and
economic growth, using the data of renewable energy generating capacity and real GDP between 1991 and 2010. The
empirical evidence suggests that renewable energy generating capacity in Japan has emerged the ability to boost and
promote economic growth in Japan in both the long-term and short-term. If the Japanese government determines to
develop the renewable energy industry vigorously, Japan's economy is likely to usher in the take-off once again in the
future, in addition that it will benefit the environmental mitigation and protection issues such as energy security.
The Genus Bilabrella Lindl. (Orchidaceae, Habenariinae): General Characteristic and Research History of The Genus
Authors: Kras Marta , Szlachetko Dariusz L.
Published: March 2015

The genus Bilabrella (Habenarinae, Orchidaceae) was described by Lindley in 1834, but within next years, different authors incorporated it as the section of the genus Habenaria Willd. From 2003, Szlachetko and Kras stated that there were no grounds for distinguishing the sections Bilabrellae and Replicatae. They restored the genus Bilabrella, transfering to it 93 species from the section Replicatae and four species new to science were described. The poor condition of the old plant materials, the lack of some type specimens for many species described by Schlechter and problems with a series of transitional forms between some species are only few reasons, why the revision of the genus has not been published so far. Bilabrella comprises orchids found in Sub-Saharan Africa, Madagascar and neighbouring islands. Bilabrella differs from other Habenariinae in its unique combination of features
The genus Triphora (Triphoreae, Orchidaceae) in Colombia
Authors: Szlachetko Dariusz L. , Baranow Przemysław , Mytnik-Ejsmont Joanna
Published: March 2015

In Colombia, four species of Triphora (Orchidaceae) are recognized. Two species (Triphora galeanoi and T. vichadaensis) are newly described. As circumscribed here, the two new species occur exclusively in Colombia apart from T. foldatsii, being known from Colombia and Venezuela, and T. gentianoides, ranging from the USA (Florida) in the north to Colombia in the south. For the species treated, a taxonomic description, synonymy and information about distribution are provided. Additionally,for the two new species, illustrations of flower parts are provided. A key for the determination of the Colombian species of Triphora is included.
Orobanche lutea Baumg. (Orobanchaceae) in Poland: revised distribution, taxonomy, phytocoenological and host relations
Authors: Piwowarczyk Renata , Krajewski Łukasz
Published: March 2015

The paper presents current distribution of Orobanche lutea Baumg. in Poland based on a critical revision of herbarium and literature data as well as results of field investigations conducted between 1999-2014. Majority of localities are centred around the Silesia-Cracow, Małopolska and Lublin-Lviv Uplands. The greatest density of sites with probably the most abundant populations in Europe is in the central part of Silesia-Cracow Upland, which, by several hundred years, was heavily exploited for calamine mining (rich in zinc, lead and silver). This resulted in the formation of large areas of gangue containing toxic heavy metals. Since limestone, dolomite, marl and postglacial calcareous clay and sands occur there in most places, the soil is often strongly calcareous. Populations of O. lutea contain here many thousands of shoots. The distribution of the species in Poland is mapped. The taxonomy, biology, ecology and threats are also discussed.
Orobanche flava (Orobanchaceae) in Poland: current distribution, taxonomy, hosts and plant communities
Authors: Piwowarczyk Renata
Published: March 2015

Orobanche flava is a species of Central European mountain ranges, mainly the Alps and Carpathian Mts. The paper presents the current distribution of O. flava in Poland based on a critical revision of herbarium and literature data as well as results of field investigations conducted between 1999 and 2014. The distribution of species is centered in southern Poland, mainly in the Carpathian Mts., and, sporadically, in the Sudeten Mts. The distribution of O. flava in Poland is mapped. The taxonomy, biology, and ecology are also discussed.
First white-flowered species of Sertifera (Orchidaceae) discovered in Colombia
Authors: Szlachetko Dariusz L. , Kolanowska Marta , Medina Trejo Ramiro
Published: March 2015

A new species of Sertifera is described and illustrated based on Colombian material. The novelty resembles Sertifera colombiana, but it is characterized by glandular leaf sheaths, larger, white flowers, ovate to oblong-ovate sepals, ligulatelanceolate petals and apically triangular lip. This is the first report of a white-flowered representative of the genus.
Orchidaceae in the Pieniny Mountains (Western Carpathians)
Authors: Frey Ludwik
Published: March 2015

Orchids constitute an important component of the Pieniny Mts. flora. The presence of 35 orchid species has been noted so far in this region. A considerable number of these species are endangered for various reasons. Eight species have been deemed extinct in the area. On the other hand, the orchid flora of the Pieniny Mts. includes species that widen their local ranges and can, thus, be considered expansive as well as new species, recently entered in the list of orchids occurring in the said mountain range (Epipactis microphylla and Epipactis muelleri). It is necessary and important to conduct an inventory of Pieniny orchid resources (the major aim of this study) that would be repeated at certain intervals, in order to know the number of stations and of individuals per population of each species, which would enable taking relevant actions needed to prevent the disappearance of these plants from the Pieniny Mts.
Overview of the Mceliece Cryptosystem and its Security
Authors: Repka Marek , Zajac Pavol
Published: March 2015

McEliece cryptosystem (MECS) is one of the oldest public key cryptosystems, and the oldest PKC that is conjectured to be post-quantum secure. In this paper we survey the current state of the implementation issues and security of MECS, and its variants. In the first part we focus on general decoding problem, structural attacks, and the selection of parameters in general. We summarize the details of MECS based on irreducible binary Goppa codes, and review some of the implementation challenges for this system. Furthermore, we survey various proposals that use alternative codes for MECS, and point out some attacks on modified systems. Finally, we review notable existing implementations on low-resource platforms, and conclude with the topic of side channels in the implementations of MECS
Mathematics and Engineering Innovation Inspired by Nature
Authors: Telgarsky Rastislav
Published: March 2015

Observation of nature and design of experiments inspires new mathematical investigations often resulting in new computer algorithms and constructions of new devices. This paper attempts to collect many cases where mathematics is inspired by the nature, and leads to direct applications in engineering.
Stability of the Semi-Implicit Discrete Duality Finite Volume Scheme for the Curvature Driven Level Set Equation in 2D
Authors: Handlovičová Angela , Kotorová Dana
Published: March 2015

Stability of the linear semi-implicit discrete duality finite volume (DDFV) numerical scheme for the solution of the regularized curvature driven level set equation is proved. Our scheme is linear, it is efficient regarding computational times. Numerical experiments confirm accuracy of the proposed scheme
An Effective Method to Improve Recovery of Heavy Oil Reservoir with Bottom Water Drive
Authors: Ju Binshan , Dai Shugoa , Fan Tailiang , Wang Xiaodong , Wu Haiqing
Published: March 2015

The coning problem for vertical wells and the ridging problem for horizontal wells are very difficult to solve by normal methods in the process of producing oil from the reservoir with bottom water drive. For heavy oil reservoirs, this difficult problem becomes more complicated for the non-Newtonian properties. An innovative completion method with downhole water sink was presented by dual-completed in oil and water columns with a packer separating the two completions for vertical wells and dual-horizontal wells that the upper well produce the fluid over the oil water contact (OWC) and down well the lower well produce the water below the OWC. The unique technique may restrain the formation of the water coning and ridging by adjusting production rates upper and lower OWC and enlarges the oil draining area, which in turn improve the oil recovery.

In order to evaluate quantatively the production performances by using the new method, numerical simulation technique was employed to find out optimal perforation segment and fittest production rates from the formation of the upper and lower OWC.

Introduction

Water coning has been regarded as the biggest problem during the oil production from a reservoir with bottom water. The phenomenon has been known for at least 100 years. The theory of water coning has been discussed by Smith, C.L.1 62 years ago and some other previous researchers before him. Resumptively, the occurrence of water coning is due to pressure gradients resulting from well production from the pay zone. The pressure gradients result in a water cone to rise toward the bottom of the producing interval. The tendency of the water to cone is offset or partially offset by gravity forces since the water has a higher specific gravity than the oil. A dynamic balance exists between the gravitational forces and the pressure gradients caused by well production. If the pressure gradient exceeds the gravitational force, water coning to the wellbore will occurs.
Mitigating Formation Invasion to Maintain Fracture Conductivity
Authors: Nguyen Philip Duke , Dusterhoft Ronald Glen , Clarkson Brad A. , Edwards William Jason
Published: March 2015

Intrusion or embedment of formation sand and fines from unconsolidated formations into proppant packs is known to diminish effective propped- fracture width, thus impacting fracture conductivity and potential well productivity. The work presented in this study shows that it is necessary to control the invasion of formation particulates into the proppant pack in the fracture to maintain its conductivity, and ultimately, the productivity of the well.

Core face materials of unconsolidated sand were used in examining their impact on fracture conductivity under high gas flow rates and frequent stress cycling. Results of laboratory testing indicates that on-the-fly coating of proppant with surface-modification agents (SMA) can provide an effective means for treating the formation surface in the fracture. The transfer of SMA from the proppant to the formation sand allows the loose, unconsolidated material to be transformed to a cohesive, bounded porous medium. As a result, it was observed that in all proppant types used in this study, the amount of formation material that appeared to be filling pore spaces in the proppant pack was much greater for the uncoated proppants. The coated proppants showed much less formation intrusion and much less formation material filling the porosity in the proppant pack. The effects of non-dDarcy flow are also examined and compared to baseline data. The beta factor of the coated proppant is lower than that of the uncoated proppant under nearly all test conditions.

Introduction

Formation fines are known to cause severe formation damage during production, limiting the potential production of the well. Many factors contribute to the migration or movement of formation fines. Various techniques have been developed in the industry through the years for examining fines-stabilizing solutions to overcome the effects of fines migration. Acidizing has been used to dissolve fines for "unblocking" and enlarging the pore throat in the formation near the wellbore to increase the permeability of the formation. Other chemical treatments, including (1) clay-stabilizing surfactants as part of the completion fluids, or (2) polymers in remedial operations, have been applied to minimize fines migration and enhance the well productivity. These treatments commonly require the treatment fluids to be injected deep into the formation matrix, allowing the surfaces of the fines and pores to be in contact and interact with the treatment fluid. Large volumes of treatment fluid are often required to achieve the desired results. Most such treatment fluids provide only temporary solutions, because they tend to desorb with time and with production of fluids from the well.
Shell's GTL: Its Technology and Design, Its Operation and Products
Authors: Senden Matthijs , Martens Frans , Steenge Wiecher , Klein Nagelvoort Rob
Published: March 2015

This paper reports on the Shell GTL technology and design, its operation and products.

The process is based on the Fischer Tropsch conversion of synthesis gas in multi-tubular reactors over a proprietary catalyst, followed by hydro-conversion and distillation. The synthesis gas is produced by partial oxidation of natural gas with pure oxygen in the Shell Gasification Process. Critical design features and performance of these main process steps are discussed.

A GTL complex is much more than just the sum of its individual process steps. The high level of integration of process and utilities poses many challenges to reliability and efficiency of operation of the complex. Important learning of eleven years of Bintulu operation will be shared. It gives insight in what makes GTL technology safe, efficient and reliable. These lessons have been implemented in the design of the 140,000 bbl/d GTL plant, which Shell is planning to realize together with QP in Qatar.

The Bintulu plant provides valuable experience in producing synthetic GTL products. A concise review will be presented. Understanding of the relationship between plant operation and product slate and – properties has been obtained, completed by experience of subsequent product performance in different applications. When new GTL capacity comes on-stream in the Middle East larger volumes of GTL product will become available to both bulk users and niche markets.

Technology and Design

The Shell's GTL technology consists of three basic stages:The 1st stage is the production of the synthesis gas from the partial oxidation process of natural gas with pure oxygen via the Shell Gasification Process (SGP), in combination with a Steam Methane Reformer (SMR). This combination enables a reliable, energy efficient and cost effective design for syngas production of the right composition.The 2nd stage is the Heavy Paraffin Synthesis (HPS), where the synthesis gas is converted into paraffin molecules. The process is a modern version of the Fischer Tropsch synthesis invented in Germany in the 1920s to produce liquid hydrocarbons from coal derived synthesis gas.The 3rd and final stage comprises of hydroconversion and distillation steps to convert the intermediate HPS product into high quality products.
Recent Advances in Carbonate Stimulation
Authors: Gdanski Rick David
Published: March 2015

Carbonate acidizing continues to be a vital process for improving the production of oil and gas wells. Laboratory studies and field evaluations of carbonate acidizing during the past 30 years have shown a continually improved understanding of the fundamental issues. This paper discusses the current state of the advances in carbonate stimulation. Average reactivity data for several limestones and dolomites are presented and can be used as improved default values for simulators. Wormhole development and structure during matrix acidizing are viewed as symmetry dominated processes controlled by fluid flow that obeys the native permeability contrasts within the matrix. The resulting simplification allows for rational treatment designs for matrix acidizing of carbonates. Zonal coverage of long carbonate sections, whether vertical or horizontal, remains a challenge. However, using the "75–25" rule for horizontal wells, creating a "thief zone" at the bottom or toe of the well, and utilizing the "top decade of permeability" rule can aid in achieving reasonable designs for maximizing productivity. The three fundamental issues of fracture acidizing are addressed: reactivity control, fluid loss control, and conductivity generation. Because synthetic polymers for acid gellants have made reactivity control easy, fluid loss control is usually the most dominant issue to be addressed in fracture acidizing.

Carbonate Reactivity

Several models are available to predict the spending of acid on carbonates. Some calculate the spending during fracture acidizing while some calculate the spending during matrix acidizing and wormhole generation. The earliest spending tests were simple spending time experiments in open beakers. However, it soon became clear that this was an inadequate procedure because mass transport definitely plays a role. Experiments conducted on quarried limestone and dolomite during the 1970s gave our first estimates of the temperature dependence of the reactivity of HCl on carbonates. These experiments suggested that limestones had incredibly high reactivity with acid such that one could assume a mass transport limited process.
Intensive Data Gathering Through a Waterflood Pilot for Redevelopment of a Giant Fractured Carbonate Field, Oman
Authors: Al-Habsi Mohammed , Stoffels Peter
Published: March 2015

Due to their strong sub-surface heterogeneity many Middle Eastern fractured carbonate reservoirs are characterized by significant and wide range of uncertainties. This paper presents a case study of one of the largest and oldest oil fields in Oman. Despite over 35 years of production through various drive mechanisms, there remains an opportunity to realize significant additional value in the field.

This paper presents the biggest data acquisition program anywhere in Oman that is ongoing in a giant fractured carbonate field to support the planned water flood project there.

A total of 28 wells have been drilled on four inverted 5-spot patterns, each containing a central water injection well, four equidistant producers and two dedicated observation wells. Each well is deviated with an S-shaped hole, so that they arch away from the linear pad on surface and end up vertically in the reservoir building a square with the injector in the middle. All the patterns have been drilled, completed and been put on production. Initial surveillance activities have been already executed and analyzed.

The primary aim of the project is to gather data about the water flood behavior in different reservoir layers in the field by running reservoir analysis logs in the wells, measuring production data and injecting tracers to track the oil and water movements. The plan is to carry out up to 25 logs (EMI, PLT, PNN, Induction) and pressure surveys (BHP, PBU, PFO) per month, in addition to coring the central water injectors. The first pad "Phase1-1" started in September 2004, the second pad "Phase1-3" in March 2005, whereas the other two pads "Phase1-2 and Phase 2-3U" came on stream in August 2005.

Towards the end of 2006 the decision based on the pilot data results will be made on whether to extend the waterflood across the whole field. The alternative would be to rely on Gas/Oil Gravity Drainage, which is a lower investment option than water flood, but ultimately would achieve a lower recovery as well. Also combinations of both development options and/or an EOR development have to be evaluated.

This paper will highlight the water flood pilot set-up and the early results from this intensive data gathering and analysis for a water flood project.
Regional Structural Analysis and Kinematic Framework of the Euphrates Graben, East Syria
Authors: Koopman Anton
Published: March 2015

The Euphrates Graben in East Syria is a "hidden" intra-cratonic rift-basin of some 120 km wide, formed by crustal extension in the Middle to Late Cretaceous. Pre-rift clastic reservoirs, differentially subsided along a complex pattern of faults, are charged from syn-rift source rocks and covered by a thick late syn-rift to post-rift seal. An early syn-rift waste rock unit exerts a decisive control on trap size in large part of the basin. Static and dynamic field models, as well as positioning of wells have proven to be critically dependent on definition of faults, and characteristics of fault geometries. Structural geological data from a variety of seismic attribute images were compiled and synthesised into a consistent and geomechanically viable regional structural framework of the basin and its fields, in order to contribute to better definition of its hydrocarbon volumes, to enhance hydrocarbon recovery, and to improve subsurface targeting of wells. The fault pattern of the rift basin is organised according to a number of highly interlocking but laterally persistent trends, most of which are inherited from already existing anisotropies in structural basement and its pre-rift overburden. A diffusely distributed and limited component of northerly trending left-lateral shear appears to be a major contributor to structural complexities within the basin. Relatively simple interpretation concepts of composite faulting, consistent with the regional framework and underpinned by experimental models and outcrop analogues, have contributed to a better understanding of the basin and its fields.

Introduction

The Euphrates Graben is a "hidden" intra-cratonic basin of some 120 km wide, which was formed by a SSW – NNE oriented crustal extension event during Middle to Late Cretaceous time (Lovelock, 1984; de Ruiter et al., 1995; Litak et al., 1998). The rifting and its associated structural relief followed a Base Upper Cretaceous Unconformity (BKU, Figures 1 and 2) of regional extent. Pre-rift clastic RESERVOIRS of the Mulussa F and Rutbah Formations (Figure 2), differentially truncated at this BKU and a more local rift-basin unconformity (RBU), subside along a complex pattern of highly interlocking faults according to different trends.
Fracture Network Modeling and Dual-Permeability Simulation of Carbonate Reservoirs
Authors: DeGraff James Michael , Meurer M. Ellen , Landis Lester Henry , Lyons Stephen Lincoln
Published: March 2015

Fractured and fracture-enhanced reservoirs are becoming increasingly important as the world's remaining hydrocarbon assets are developed. New modeling and simulation techniques must be developed to guide business decisions, improve economic forecasts, and maximize productivity. To address this need, a fractured reservoir modeling and simulation workflow was developed to integrate evolving technology for fracture characterization, geologic modeling, and flow simulation. The workflow is based on: common-scale geologic and simulation models;fine-scale element models to compute effective matrix permeability;analysis of fracture data from core, image logs, and outcrop; andintegration of field performance, structure, stratigraphy, and lithology.

Directional equivalent fracture permeability, porosity, and matrix block dimensions are estimated using discrete fracture network (DFN) and 3D geologic models, while effective matrix permeability is derived using proprietary technology (patent pending). Fracture analysis consists of identifying structural and stratigraphic controls on fracture data from available sources, and then using this knowledge to derive a set of rules to populate a DFN model. Dual-porosity/permeability reservoir simulation models are built in EMP Power™ Pusing similar grid geometry and cell size, effective matrix properties, and DFN-generated fracture properties. Simulation results show a better history match with less iteration than previous models when compared with multiphase production history. In our test cases, dual-porosity/ permeability models more accurately capture the impact of fractures on fluid flow than do single-medium models. Our study also demonstrates an effective and efficient process for dual-porosity/permeability modeling and simulation of fractured reservoirs.

Fractured Reservoir Modeling and Simulation Workflow

The integrated workflow discussed here addresses fractured reservoir characterization and fluid-flow simulation, using ExxonMobil proprietary and vendor software tools. It generates effective matrix properties, directional fracture permeabilities, and equivalent matrix block dimensions that are used to build dual-porosity/dual-permeability reservoir simulation models. The workflow is as follows.
Household transmissibility of avian influenza A (H7N9) virus, China, February to May 2013 and October 2013 to March 2014
Authors: Yang Y , Zhang Y , Fang L , Halloran M E , Ma M , Liang S , Kenah E , Britton T , Chen E , Hu J , Tang F , Cao W , Feng Z , Longini Jr I M
Published: March 2015

To study human-to-human transmissibility of the avian influenza A (H7N9) virus in China, household contact information was collected for 125 index cases during the spring wave (February to May 2013), and for 187 index cases during the winter wave (October 2013 to March 2014). Using a statistical model, we found evidence for human-to-human transmission, but such transmission is not sustainable. Under plausible assumptions about the natural history of disease and the relative transmission frequencies in settings other than household, we estimate the household secondary attack rate (SAR) among humans to be 1.4% (95% CI: 0.8 to 2.3), and the basic reproductive number R0 to be 0.08 (95% CI: 0.05 to 0.13). The estimates range from 1.3% to 2.2% for SAR and from 0.07 to 0.12 for R0 with reasonable changes in the assumptions. There was no significant change in the human-to-human transmissibility of the virus between the two waves, although a minor increase was observed in the winter wave. No sex or age difference in the risk of infection from a human source was found. Human-to-human transmissibility of H7N9 continues to be limited, but it needs to be closely monitored for potential increase via genetic reassortment or mutation.
Assessing the Cognitive Demands of a Century of Reading Curricula
Authors: Stevens Robert J. , Lu Xiaofei , Baker David P. , Ray Melissa N. , Eckert Sarah A. , Gamson David A.
Published: March 2015

This research investigated the cognitive demands of reading curricula from 1910 to 2000. We considered both the nature of the text used and the comprehension tasks asked of students in determining the cognitive demands of the curricula. Contrary to the common assumption of a trend of simplification of the texts and comprehension tasks in third- and sixth-grade curricula, the results indicate that curricular complexity declined early in the century and leveled off over the middle decades but has notably increased since the 1970s, particularly for the third-grade curricula.
Will VAMS Reinforce the Walls of the Egg-Crate School?
Authors: Johnson Susan Moore
Published: March 2015

Throughout the United States there is an increasing trend toward using value-added methods (VAMs) for high-stakes decisions. When policymakers use VAMs to identify, reward, and dismiss teachers, they may perpetuate the egg-crate model of schooling and undermine efforts to build instructional capacity schoolwide. At any time, in any school, some teachers are more knowledgeable, experienced, and skilled than others. Schools function best when they continuously leverage teachers’ expertise so that all students in all classrooms are well served. Drawing from research about the incentives and norms that influence teachers’ work within schools, this article illustrates what can happen when these methodologies are used to make job decisions and it identifies the hazards of using VAMs for this purpose. Contextualizing this within the larger discussion about performance evaluation systems, the article suggests how VAMs can be used productively as one source of information to promote improvement schoolwide.