bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasma rico em plaquetas para consolidação de ossos longos
Authors: Lenza Mário , Ferraz Silvia de Barros , Viola Dan Carai Maia , Santos Oscar Fernando Pavão dos , Cendoroglo Neto Miguel , Ferretti Mario
Published: April 2013

OBJETIVO: Avaliar a efetividade do uso de plasma rico em plaquetas como coadjuvante para a consolidação óssea de ossos longos. MÉTODOS: A estratégia de busca abrangeu a Cochrane Library (via Central) e o MEDLINE (via PubMed). Não houve restrições de idioma ou meios de publicações. A última estratégia de busca foi realizada em dezembro de 2011. Foram incluídos ensaios clínicos randomizados que avaliaram o uso do plasma rico em plaquetas como medicação coadjuvante para acelerar a consolidação dos ossos longos (fraturas agudas, pseudoartroses e defeitos ósseos). Os desfechos de interesse para esta revisão compreenderam: consolidação óssea, eventos adversos, custos, dor e qualidade de vida. Os autores selecionaram os estudos elegíveis, avaliaram a qualidade metodológica e extraíram os dados. Não foi possível realizar análise quantitativa dos estudos agrupados (meta-análises). RESULTADOS: Foram incluídos dois ensaios clínicos prospectivos randomizados, envolvendo um total de 148 participantes. Um deles comparou proteína morfogenética óssea recombinante humana 7 versus PRP para o tratamento de pseudoartroses; o outro avaliou os efeitos de três tratamentos coadjuvantes para a consolidação de osteotomias valgizantes da tíbia (plasma rico em plaquetas, plasma rico em plaquetas mais células estromais da medula óssea e sem tratamento coadjuvante). Ambos possuíam baixo poder estatístico e moderado a alto risco de viés. CONCLUSÃO: Não houve evidências conclusivas que sustentassem o uso de plasma rico em plaquetas como coadjuvante para auxiliar a consolidação óssea de fraturas, pseudoartrose ou defeitos ósseos.
Influence of substratum surface roughness on periphytic algal community structure in a shallow tropical reservoir
Authors: Souza Mariane Lima de , Ferragut Carla
Published: April 2013

AIM: This study aimed to evaluate the algal periphytic community structure on substrates with differing surface roughness in early and longer-term colonization; METHODS: Periphyton was sampled after 30 days (June 24 to July 24, 2008) and 5 days (July 07 to July 12, 2010) substrate exposure during dry season. Plastic slides were used as artificial substrate. Treatments were smooth surface (control), low roughness, medium roughness and high roughness. Samples were collected for limnological condition and periphyton (chlorophyll-a, AFDM, algal biovolume and density, species richness and diversity) analysis; RESULTS: Periphytic biomass, algal density and biovolume had no significant difference among treatments after 30 and 5 days colonization time. Taxonomic similarity was the lowest among treatments and the greatest difference occurred between control and treatments with roughness surface. Bacillariophyceae biovolume decreased with increasing surface roughness. Adherence forms, algal classes and species descriptors were significantly different after 5 days colonization time, especially in medium e high roughness surface. In the colonization advanced phase only species descriptors differ among treatments. Periphytic algae with pads and stalks for adherence decreased with increasing surface roughness. CONCLUSION: Substrate physical properties had little or no influence on periphyton biomass accumulation, total density and biovolume in this study, but algal assemblages were sensitive to changes in the microtopography. More studies are needed to increase understanding of the relation substrate-periphyton in tropical ecosystems.
How many species of cladocerans (Crustacea, Branchiopoda) are found in Brazilian Federal District?
Authors: Sousa Francisco Diogo Rocha , Elmoor-Loureiro Lourdes Maria Abdu
Published: April 2013

AIM: This study aimed provides a checklist of cladocerans and also an evaluation of richness and species composition in the Federal District, Brazil. METHODS: Checklist of cladocerans was obtained evaluating data from the literature, from taxonomic collection (Elmoor-Loureiro's collection) and from fauna surveys conducted over more than three decades in different types of aquatic environments. RESULTS: The 57 water bodies studied showed 56 species, of which 14 are new records. The number of species contained in the list displayed corresponds to 85% of what was expected for richness estimators. The highest number of species was observed in the lentic water bodies (52), which also presented the specific composition of fauna (R = 0.110; p = 0.016), possibly because there were samples taken among the aquatic vegetation. According to our understanding, some species may be subject to local extinctions because they inhabit water bodies located exclusively in urban areas, which can lead to a decline in richness. CONCLUSION: Thus, the results of this study can assist in monitoring aquatic environments and in selection of new areas for surveys of cladocerans in the Federal District.
Marasmius (Basidiomycota - Marasmiaceae) do Parque Estadual das Fontes do Ipiranga, São Paulo, SP, Brasil: seção Sicci
Authors: Puccinelli Carla , Capelari Marina
Published: April 2013

São descritas, ilustradas e comentadas catorze espécies de Marasmius seção Sicci, do Parque Estadual das Fontes do Ipiranga (PEFI). São apresentadas chaves de identificação para os táxons das séries Atrorubentes, Haematocephali e Leonini. As espécies de M. aff. pseudoniveus e M. bellus são citadas pela primeira vez para o PEFI; M. bambusiniformis e M. ferrugineus pela primeira vez para o estado de São Paulo e M. congregatus e M. musicola pela primeira vez para o Brasil.
Flora polínica da Reserva do Parque Estadual das Fontes do Ipiranga (São Paulo, Brasil): família: 107-Euphorbiaceae s.l
Authors: Corrêa Angela Maria da Silva , Barros Maria Amélia Vitorino da Cruz , Silvestre-Capelato Maria Stella Fernandes , Pregun Michel Aprigio , Raso Priscila Gardino , Cordeiro Inês
Published: April 2013

Foram estudados os grãos de pólen de 14 gêneros e 27 espécies de Euphorbiaceae s.l., ocorrentes na "Reserva do Parque Estadual da Fontes do Ipiranga: Actinostemon klotzschii (Didr.) Pax, Alchornea sidifolia Müll. Arg., A. triplinervia (Spreng.) Müll. Arg., Croton floribundus Spreng., C. fuscescens Spreng., C. glandulosus L., C. lundianus (Didr.) Müll. Arg., C. organensis Baill., C. salutaris Casar., C. vulnerarius Baill., Dalechampia triphylla Lam., Euphorbia heterophylla L., E. hirta (L.) Millsp., E. hyssopifolia (L.) Small, E. peplus L., Gonatogyne brasiliensis Müll. Arg., Hieronyma alchorneoides Allemão, Maprounea guianensis Aubl., Pera obovata (Klotzsch) Baill., Phyllanthus caroliniensis Walt., P. niruri L., P. tenellus Roxb., Plukenetia serrata (Vell.) L.J. Gillespie, Sapium glandulosum (L.) Morong, Savia dictyocarpa Müll. Arg., Sebastiania klotzschiana (Müll. Arg.) Müll. Arg., S. serrata (Baill.) Müll. Arg. Para todos os táxons estudados, são apresentadas descrições, ilustrações, e observações adicionais, bem como chaves polínicas para a identificação das espécies de alguns gêneros.
Notas taxonômicas para Euphorbiaceae s.l. do nordeste do Brasil
Authors: Lucena Maria de Fátima de Araújo , Alves Marccus
Published: April 2013

Recentes estudos taxonômicos desenvolvidos na Caatinga, sobre Euphorbiaceae, incluindo coletas e levantamentos em 14 herbários revelaram o acréscimo de 29 táxons ao cheklist anteriormente conhecido para a família na região. Os táxons são apresentados acompanhados de alguns sinônimos, material tipo e espécimes de referência. São também apresentados comentários sobre distribuição geográfica, ambientes de ocorrência e caracteres diagnósticos. O estudo amplia a diversidade de Euphorbiaceae para o semi-árido do Brasil e ressalta a importância de coletas intensivas em novas áreas, assim como a análise minuciosa dos acervos botânicos já disponíveis.
Avaliação clínica da deglutição em unidade de terapia intensiva
Authors: Padovani Aline Rodrigues , Moraes Danielle Pedroni , Sassi Fernanda Chiarion , Andrade Claudia Regina Furquim de
Published: April 2013

OBJETIVO: Relatar os resultados da avaliação clínica completa da deglutição em pacientes críticos de um hospital de ensino de grande porte na cidade de São Paulo. MÉTODOS: Foi realizado um estudo prospectivo, descritivo, no período de setembro a novembro de 2009, em uma unidade de terapia intensiva de emergências clínicas de trinta leitos, de um hospital terciário de grande porte do Brasil. Foram encaminhados 35 pacientes para a avaliação fonoaudiológica clínica da deglutição. Para a avaliação clínica completa da deglutição na unidade de terapia intensiva, foram preconizados os seguintes protocolos: Protocolo de Avaliação Preliminar (PAP), Protocolo de Avaliação do Risco para Disfagia (PARD) e Protocolo de Introdução e Transição da Alimentação por Via Oral (PITA). RESULTADOS: Neste estudo, foi constatada uma prevalência de 63% de disfagia orofaríngea (DO) na UTI, sendo a maioria destas classificadas como moderada e moderada-grave (39%). Entre os pacientes encaminhados para avaliação da deglutição, 74% apresentaram intubação orotraqueal prévia. A análise estatística revelou as variáveis que poderiam classificar corretamente os pacientes como tendo ou não DO nos testes clínicos. Esses indicadores clínicos incluíram: força da tosse, coordenação pneumofonoarticulatória, gravidade da disfonia e elevação laríngea. Vinte e seis pacientes (74%) completaram todos os protocolos. Desse total, 38% retornaram à dieta regular. CONCLUSÃO: A prática com protocolos padronizados mostra-se como uma importante opção no gerenciamento da disfagia orofaríngea na unidade de terapia intensiva.
Relação entre pausas silentes e classe gramatical em narrativas de crianças com distúrbio específico de linguagem
Authors: Befi-Lopes Debora Maria , Pedott Paula Renata , Bacchin Letícia Bondezan , Cáceres Ana Manhani
Published: April 2013

OBJETIVO: Verificar se há influência das classes gramaticais no tempo médio de pausas silentes durante a produção de narrativas em crianças em desenvolvimento típico de linguagem e em crianças com distúrbio específico de linguagem (DEL). MÉTODOS: Participaram da pesquisa 20 crianças com DEL e 40 em desenvolvimento típico de linguagem com idade variando entre 7 e 10 anos. Cada sujeito elaborou 15 narrativas, baseadas em uma sequência de quatro cenas cada, com aumento gradual de complexidade. Após as análises das amostras foram identificados os substantivos, adjetivos, verbos, conjunções, preposições e pronomes. Num segundo momento, as amostras foram submetidas a um software para análise das pausas silentes (tempo em milissegundos), que permitiu o levantamento do tempo das pausas imediatamente anteriores a cada uma dessas categorias gramaticais. RESULTADOS: Ambos os grupos apresentaram menor duração da pausa silente quando esta precedia os substantivos e maior quando esta precedia as conjunções. A análise estatística evidenciou que os grupos diferem em todas as classes de palavras, com média de pausas silentes maiores nas crianças com DEL. CONCLUSÃO: A classe gramatical influencia a duração da pausa silente, sendo esta menor quando precede substantivos e maior quando precede conjunções. Além disso, os indivíduos com DEL possuem pausas silentes mais longas possivelmente em decorrência de suas dificuldades com o processamento da linguagem.
Effect of lighting on frequency and severity of road accidents
Authors: Yannis George , Kondyli Alexandra , Mitzalis Nikolaos
Published: April 2013

The purpose of this study was to investigate the effect of lighting conditions on the frequency and severity of road accidents at both urban and rural roads in Greece. A total of 358 485 police-recorded accidents were analysed and the proposed models were developed with the use of log-normal regression. The application of these models allowed the investigation of the influence of road lighting and other parameters such as weather conditions, accident type and vehicle type on the number of casualties and injuries. It appears that road lighting contributes to the reduction of the number of accidents and their severity and that this influence increases with the increase of the severity of the accidents. The absence of street lighting during nighttime has the highest impact on the number of fatalities and serious injuries. The results show that nighttime lighting has great potential in improving traffic safety and reducing the accident severity, especially for persons killed and seriously injured. Identification of the effect of lighting on road safety should benefit road safety policy decision makers in designing and implementing appropriate road safety measures (infrastructure improvement, safety campaigns and so on).
A traffic stream model for heterogeneous traffic conditions
Authors: Thankappan Ajitha , Vanajakshi Lelitha
Published: April 2013

A comprehensive understanding of speed–flow–density relations is an essential requirement in planning, design and operation of transportation systems. Many researchers have investigated the nature of speed–flow–density relationships, commonly known as stream models, under homogeneous traffic conditions. However, those models may not be the best under Indian traffic conditions. Indian traffic differs significantly from homogeneous traffic and may need a different treatment for analysis. Not much research has been reported on this important aspect so far from India. The present study is an attempt to develop an optimal traffic stream model suitable for the heterogeneous traffic flow condition existing in India, taking Chennai as a case study. A two-regime speed–density relationship was developed using a conventional optimisation algorithm. Using this, the speed–flow and flow–density relationships were theoretically derived. The results indicate that the proposed model is able to represent the steady-state macroscopic behaviour of the heterogeneous and less lane-disciplined traffic stream under study with reasonable accuracy.
Design parameters of vortex settling basin
Authors: Ansari Mujib Ahmad , Athar Mohd
Published: April 2013

Experimental results concerning the effects of width ratio and diameter ratio on the sediment removal efficiency of a vortex settling basin are reported. Available relations for sediment removal efficiency of a vortex settling basin are tested and an equation is developed and presented using data collected in the present investigation and laboratory and field data collected from the literature. The existing relations for sediment removal efficiency were found not to produce satisfactory results for a wide range of hydraulic and geometrical variables.
Decomposing risk: Landscape structure and wolf behavior generate different predation patterns in two sympatric ungulates
Authors: Gervasi Vincenzo , Sand Håkan , Zimmermann Barbara , Mattisson Jenny , Wabakken Petter , Linnell John D. C.
Published: April 2013

Recolonizing carnivores can have a large impact on the status of wild ungulates, which have often modified their behavior in the absence of predation. Therefore, understanding the dynamics of reestablished predator–prey systems is crucial to predict their potential ecosystem effects. We decomposed the spatial structure of predation by recolonizing wolves (Canis lupus) on two sympatric ungulates, moose (Alces alces) and roe deer (Capreolus capreolus), in Scandinavia during a 10‐year study. We monitored 18 wolves with GPS collars, distributed over 12 territories, and collected records from predation events. By using conditional logistic regression, we assessed the contributions of three main factors, the utilization patterns of each wolf territory, the spatial distribution of both prey species, and fine‐scale landscape structure, in determining the spatial structure of moose and roe deer predation risk. The reestablished predator–prey system showed a remarkable spatial variation in kill occurrence at the intra‐territorial level, with kill probabilities varying by several orders of magnitude inside the same territory. Variation in predation risk was evident also when a spatially homogeneous probability for a wolf to encounter a prey was simulated. Even inside the same territory, with the same landscape structure, and when exposed to predation by the same wolves, the two prey species experienced an opposite spatial distribution of predation risk. In particular, increased predation risk for moose was associated with open areas, especially clearcuts and young forest stands, whereas risk was lowered for roe deer in the same habitat types. Thus, fine‐scale landscape structure can generate contrasting predation risk patterns in sympatric ungulates, so that they can experience large differences in the spatial distribution of risk and refuge areas when exposed to predation by a recolonizing predator. Territories with an earlier recolonization were not associated with a lower hunting success for wolves. Such constant efficiency in wolf predation during the recolonization process is in line with previous findings about the naïve nature of Scandinavian moose to wolf predation. This, together with the human‐dominated nature of the Scandinavian ecosystem, seems to limit the possibility for wolves to have large ecosystem effects and to establish a behaviorally mediated trophic cascade in Scandinavia.
A Superior, High-Performance Enzyme for Breaking Borate Crosslinked Fracturing Fluids Under Extreme Well Conditions
Authors: Zhang Bin , Huston Adrienne , Whipple Lawrence , Urbina Hugo , Barrett Ken , Wall Mark , Hutchins Rick , Mirakyan Andrey
Published: April 2013

Enzyme breakers have been previously used for hydrolyzing guar gels at temperatures below 150°F. There is an industry-wide demand for enzyme breakers that can function under higher-temperature (200–250°F) and extreme pH (≥10.5) conditions. To meet this demand, efforts have been made to develop an exceptionally thermostable cellulase enzyme, referred to hereafter as mannanase, that was originally discovered in a hydrothermal vent sample. This mannanase exhibits well-differentiated performance under extreme downhole conditions encountered in gas shales and deeper oil/gas wells.

This superior mannanase can effectively break linear and borate crosslinked guar under broad ranges of temperature (80°F up to at least 225°F as seen by rheology, and up to 275°F using residual activity analysis) and pH (3.0 up to 10.5). The results of rheological tests show that only a small dose is required (100 ppm or less) to achieve the complete break. The enzymatic reaction can be triggered by the changes of temperature and pH during fracturing operations. This mannanase also exhibits a dose response that allows the operator to generate a desirable viscosity/time profile by adjusting enzyme dosage. Even in the presence of fluid additives, such as buffers, salts, stabilizers, and crosslinkers, this mannanase is active for effective viscosity reduction.

This mannanase breaker belongs to the glucanase family. It reduces gel viscosity by specifically targeting β-1,4 glycosidic bonds between the mannose units in guar. The carbohydrate-profiling tests demonstrate that this enzyme effectively and efficiently breaks the long-guar polymers into small, soluble fragments that will eliminate gel rehealing. The conductivity tests demonstrate extensive cleaving of guar and removal of polymer residues that cause formation damage and reduce fracture conductivity.
Is That Radial Flow? What Can be Learned From Buildup Analysis of Multiply-Fractured Horizontal Wells In Unconventional Reservoirs
Authors: Lougheed D. , Santo M. , Ewens S.
Published: April 2013

Buildup data from multiply-fractured horizontal wells (MFHW) in tight (micro to nano-Darcy permeability) unconventional reservoirs often display a derivative signature which appears like radial flow and is frequently misinterpreted as such without due consideration of the expected flow regimes from these systems. Studies based on both numerical and analytical modeling suggest that radial flow regimes will not be observed, due to the large number of hydraulically induced fractures, and the geometry of a typical MFHW completion. Analysis of production data continues to show no evidence of radial flow, but instead, reveals that linear flow regimes dominate for the majority of a well's lifetime. This is more consistent with the expected flow behavior, and leads to confusion on how to interpret buildup data that often appear like radial flow. This paper provides explanations for the different pressure behavior exhibited during a buildup. In doing so, the value of conducting a buildup test to assess the reservoir characteristics and completion effectiveness, is demonstrated. Two examples of actual buildup data obtained from MFHWs completed in unconventional reservoirs are presented to support the findings of this paper.
Analytical and Numerical Solutions for Multiple-Matrix in Fractured Reservoirs: Application to Conventional and Unconventional Reservoirs
Authors: Torcuk Mehmet A. , Kurtoglu Basak , Alharthy Najeeb , Kazemi Hossein
Published: April 2013

In this paper we present a new method to model heterogeneity and flow channeling in petroleum reservoirs—specially reservoirs containing interconnected microfractures. The method is applicable both to conventional and unconventional reservoirs where the interconnected microfractures form the major flow path. The flow equations, which could include flow contributions from matrix blocks of various size, permeability and porosities, are solved by the Laplace transform analytical solutions and finite-difference numerical solutions. The accuracy of flow from and into nano-Darcy matrix blocks is of great interest to those dealing with unconventional reservoirs; thus, matrix flow equations are solved using both pseudo-steady- state (PSS) and un-steady-state (USS) formulations and the results are compared.

The matrix blocks can be of different sizes and properties within the representative elementary volume (REV) in the analytical solutions, and within each control volume (CV) in the numerical solutions. While the analytical solutions were developed for slightly compressible rock-fluid linear systems, the numerical solutions are general and can be used for non- linear multi-phase, multi-component flow problems.

The mathematical solutions were used to analyze the long-term performance of a gas well and an oil well in two separate unconventional reservoirs. Finally, the formulations were used to assess enhanced oil recovery potential from a typical nano- Darcy matrix block. It is concluded that matrix contribution to flow is very slow in a typical low-permeability unconventional reservoir and much of the enhanced production is from the fluids contained in the microfractures than in the matrix.

In addition to field applications, the mathematical formulations and solution methods are presented in a transparent fashion to allow easy utilization of the techniques for reservoir and engineering applications.
Understanding Unconventionals by Multidisciplinary Integration - A Microseismic Based Tale of the Haynesville Shale
Authors: Gangopadhyay Abhijit , Malayalam Atif , Lucas Jennifer , Gillham Travis , Liu Shujie , Faz Ignacio , Wirnkar Fabian
Published: April 2013

Microseismic data acquired using a near-surface array in four horizontal wells in the Haynesville shale in Shelby and San Augustine counties, Texas, were analyzed and integrated with geoscience, petrophysics, completions, and flow-back performance data. Horizontal sections of the wells are ~5,000 feet long, and stimulated with twelve stages. Analyses of microseismic events from the first two wells to understand fracture containment, led to drilling the fourth as a transverse across the target zone. A production log was also run in the same well to identify zones in the Haynesville that produced the highest rate of gas. Fewer microseismic events were recorded during stimulations of the northward wells, and resulting fractures were more elongated than the southward wells. Fracture half-lengths based on all located microseismic events from the four wells range between ~400 feet and ~700 feet. The derived fracture orientations are consistent with the regional SHmax and confirm our choice of well azimuths. Some prominent fractures align with those inferred from 3-D seismic based coherency attribute, indicating that pre-existing fractures were activated. Correlations of microseismic event locations with gamma ray logs along the laterals revealed that fractures initiated better when the log values are <110 API, an observation consistent with Lithology-based brittleness index. The completions strategy included pumping resin coated sand in one well, combining that with white sand in others, and stimulating the shortest lateral with the same proppant volume and stages as others. Flow-back performance of the shortest lateral was strong enough to suggest the potential for reserve improvement by shortening stage length. The interpreted production log shows that stages near the heel are most productive compared to the first three stages near the toe, leading to an estimate of the effective stimulated rock volume. Summarily, the study provides multidisciplinary insights into future horizontal designs in the area.
Time Dependent Fracture Interference Effects in Pad Wells
Authors: Manchanda Ripudaman , Sharma Mukul M. , Holzhauser Shawn
Published: April 2013

Hydraulic fracturing in shale formations induces microseismic events in a region we refer to as the microseismic volume. Many of these microseismic events are signatures of failure in the formation that are believer to be a result of induced fractures, beyond the primary propped fracture. Aerially extensive microseismicity may be evidence that these induced, unpropped fractures occur and extend spatially beyond the propped fracture in many unconventional reservoirs.

To illustrate these effects, microseismic and radioactive tracer data is presented for four laterals drilled and fractured from a single pad. Our simulations show that the opening of these induced, unpropped fractures results in significant temporary changes to the stress field in the rock. One consequence of this is that later fracture stages tend to propagate into the open fracture networks of induced, unpropped fractures created earlier due to stress reorientation. This can lead to inefficient usage of time, fluid, proppant, and capital since the region being stimulated has already been stimulated by the previous stage. By analyzing the net pressure, radioactive tracer and microseismic data from the four-well pad, we show that these induced, unpropped fractures close over time (over a period of hours) as the fracture fluid leaks-off. This relaxes the stresses and subsequent induced fractures are no longer subjected to the significantly altered stresses, allowing for more efficient fracture network coverage by subsequent fractures in a horizontal well. Based on the data presented and computer simulations, we propose the idea of establishing a minimum time between fracturing in the microseismic volume of a recently fractured region. The time required for the induced unpropped fractures to close can be calculated from our models and varies based on the reservoir and fluid properties but is typically on the order of hours. One example of how this is accomplished in practice is zipper fracs. However, our work suggests that there may be other fracture sequencing strategies for accomplishing this as well.
Relationship Between Organic Shale Microstructure and Hydrocarbon Generation
Authors: Curtis M. E. , Sondergeld C. H. , Rai C. S.
Published: April 2013

Interest in shale resource plays has shifted from gas to gas condensate and oil because of economic pressures. From a geochemical perspective, this represents a shift in thermal maturity of the organic matter in the host rock. It is believed that the development of secondary nanoporosity in the organic matter is linked to the thermal maturity of the shale; therefore thermal maturity has an effect on both storage and permeability in plays dominated by organic porosity. Previous research on thermal maturity and organic porosity in gas shales shows a trend of porosity occurring in the gas window (> 1.2% Ro); however, to date, few investigations of microstructure in the oil window have been carried out.

To investigate the organic porosity in low thermal maturity shale samples, a combination of Focused Ion Beam (FIB) milling and Scanning Electron Microscopy (SEM) was utilized. This combination permits careful sample preparation that preserves the microstructure, minimizes artifacts, and provides the ability to image the nanoscale organic pores which are below the resolution of visible light. Initial FIB/SEM results on oil window shale samples suggest a completely different type of porosity development within organic matter in the oil window (~0.6-1.0% Ro) versus the gas window. Oil window porosity development in the organic matter is exhibits crack-like features that appear to be a product of hydraulic fracturing and shrinkage of organic matter. This is in stark contrast to the porosity observed in gas window shales.

The crack-like features observed in the organic matter of oil window shales have immediate implications for local expulsion of oil. Excess oil being "incompressible" must leave the generation site; this can be facilitated through pressure build up caused by the roughly 50% excess volume which leads to localized hydraulic fracturing.
Evaluation of Well Performance for the Slot-Drill Completion in Low and Ultra-Low Permeability Oil and Gas Reservoirs
Authors: Odunowo T. O. , Moridis G. J. , Blasingame T. A. , Olorode O. M. , Freeman C. M.
Published: April 2013

Low to ultralow permeability formations require "special" treatments/stimulation to make them produce economical quantities of hydrocarbon and at the moment, multi-stage hydraulic fracturing (MSHF or MHF) is the most commonly used stimulation method for enhancing the exploitation of these reservoirs. Recently, the slot-drill (SD) completion technique was proposed as an alternative treatment method in such formations (Carter 2009).

This paper documents the results of a comprehensive numerical simulation study conducted to evaluate the production performance of the SD technique and compare its performance to that of the standard MSHF approach. We investigated three low permeability formations of interest, namely a shale-gas, a tight-gas, and a tight/shale-oil formation. The simulation domains were discretized by using Voronoi gridding schemes to create representative meshes of the different reservoir and completion systems modeled in this study.

The results from this study indicated that the SD method does not, in general, appear to be competitive in terms of reservoir performance and recovery compared to the more traditional MSHF method. Our findings indicate that the larger surface area to flow that results from the application of MSHF is much more significant than the higher conductivity achieved using the SD technique. However, there may exist cases, e.g., lack of adequate water volumes for hydraulic fracturing, or very high irreducible water saturation that leads to adverse relative permeability conditions and production performance, in which the low-cost SD method may make production feasible from an otherwise challenging (if not inaccessible) resource.
Stochastic Modeling of Two-Phase Flowback of Multi-Fractured Horizontal Wells to Estimate Hydraulic Fracture Properties and Forecast Production
Authors: Williams-Kovacs J. D. , Clarkson C. R.
Published: April 2013

Although high-frequency fluid production and flowing pressures (hourly or greater) are commonly gathered in multi-fractured horizontal wells (MFHW), this data has rarely been used by industry in a quantitative manner to characterize hydraulic fracture or reservoir parameters and there has been ongoing debate about the usefulness of this data. It is likely that the multi-phase flow nature and the possibility of early data being dominated by wellbore storage have deterred many analysts.

This work will expand on the flowback analysis work presented by Clarkson (2012b). Consistent with that work, our interpretation is that the early flowback data corresponds to wellbore + fracture volume depletion (storage) and it is assumed that fracture storage volume is much greater than wellbore storage. From this flow-regime, bulk permeability (dominated by fracture permeability) and effective fracture half-length can be estimated. However, as pointed out by Clarkson (2012b) there is a large degree of uncertainty in this type of analysis as a result of the number of unknowns which are being adjusted to provide an adequate history match. To better understand the uncertainty and the impact of each parameter, stochastic simulation was used to provide a range of parameter values, which provide an adequate fit of the data, and to determine which parameters have the greatest impact on the match. Stochastic simulation is also used to derive a long-term forecast using parameters derived from flowback analysis. Additional improvements over previous work include the consideration of different fracture geometries, the use of the matchstick model to estimate fracture permeability and additional constraints on relative permeability curve selection. The field cases presented by Clarkson (2012b) for shale gas reservoirs are reanalyzed for proof of concept and demonstration of the developed techniques.
Effect of Reservoir Heterogeneity on Improved Shale Oil Recovery by CO2 Huff-n-Puff
Authors: Chen Cheng , Balhoff Matthew , Mohanty Kishore K.
Published: April 2013

An equation-of-state based compositional reservoir simulator, UT-COMP, is used to simulate the improved oil recovery by CO2 huff-n-puff in a shale matrix typical of the Bakken Formation. Non-aqueous components are carefully lumped into seven pseudo components. Permeability fields with various heterogeneity and correlation lengths are generated. UT-COMP is able to solve the compositional model, despite the permeability difference between the fracture and matrix being six orders of magnitude. Multiple cycles of CO2 huff-n-puff are simulated and compared with production by primary depressurization. The oil is first contact miscible with the injected CO2 under the reservoir pressure. Simulations show that primary recovery outperforms CO2 huff-n-puff in an ideally homogenous reservoir because injected CO2 moves deep into the reservoir without much increase in near-well pressure, while CO2 huff-n-puff outperforms primary recovery if there exists a low-permeability region which keeps CO2 in the near-well bore injection region. In the latter case, the final recovery using CO2 huff-n-puff is higher than that from primary depressurization; the recovery in a single cycle is about 3.3%, which increases to 3.5% in about 3 cycles. The recovery factor after 1000 days by primary depressurization with production pressure of 1000 psi is 11.6%, which is in agreement with existing studies. The recovery increase can be fit by a two-parameter exponential function and the rate coefficient is found to be insensitive to correlation length, while depends mainly on reservoir heterogeneity. A linear relationship between heterogeneity and rate coefficient is obtained. This work is the first to investigate the effect of heterogeneity on improved hydrocarbon recovery by CO2 huff-n-puff, and will be valuable in understanding the coupling between shale properties and oil recovery.
Urbanization Prospects in Asia: A Six-Country Comparison
Authors: Rob Ubaidur , Talukder Md. Noorunnabi
Published: April 2013

Yet rural in nature, Asia is proceeding with a wide-ranging scale and fast pace of urbanization, resulting in accelerated economic growth. This article attempts a comparison on urbanization of six largest Asian countries: Bangladesh, China, India, Indonesia, Pakistan, and the Philippines. Among these countries, urban transition is underway in China, Indonesia, and the Philippines, which are also on track to mature as middle-income countries. India and Pakistan will soon graduate from low-income to lower-middle income countries, reaching the platform for faster urbanization with consequent economic growth. Regardless of the level of urbanization across countries, cities generate four-fifths of national income and the prominence of cities in generating country's national income is escalating. Still, urbanization primarily takes place through the development of large cities with surrounding industrial zones. Large cities will continue to play a significant role in absorbing future anticipated growth, but a decrease of growth rates in large cities is expected. Most of future city growth will occur in medium- and small-sized cities where existing coverage of basic public services is grossly inadequate, that entails greater concentration of power, investment, and services. To maximize the benefits of urbanization, countries need to judiciously plan the course of future urbanization—whether it should be a concentrated growth, a balanced growth, or a distributed growth.
Field Methods for Discovering Practical Wisdom: The Microdynamics of Going beyond Technical Rationality in Real-World Practice
Authors: Gray-Murray Jo Ann , Leary Meggan , Watts Michelle , Xiong Fue , Willis Earnestine
Published: April 2013

Practical wisdom is essential to occupational and professional practice. However, the emphasis on technical rationality in these domains neglects the necessity of practical wisdom in doing specialized, skilled work. Microdynamic methods for analyzing social action enabled the discovery and examination of practical wisdom in two interactional episodes from community health work. Practical wisdom was found in specific acts: in adaptation to and interpretation of logical forces and interactional rules of these acts; and in deliberation among choices to reach intended outcomes. Cultivating skills in microdynamic methods for finding and analyzing practical wisdom is an essential tool for practitioners and organizations.
Risk Factors for Suicidal Ideation among College Students: 6-Month Follow-up
Authors: Shtayermman Oren , Fayda Matthew G. , Knight Kim L.
Published: April 2013

This study was a 6-month follow-up study examining risk factors for suicide among college students. The sample included 95 participants who also participated in the first data collection period. Online questionnaires were completed by participants from the first wave. Thirteen percent of the sample had clinically significant levels of suicidal ideation, 3.2% met the criteria for dysthymia, and 15.8% and 17.9% met the DSM-IV criteria for a diagnosis of Major Depressive Disorder and Generalized Anxiety Disorder, respectfully. About 9.5% met criteria for alcohol dependence and 16.8% met criteria for drug abuse. Overall, 23% of the variance was explained in suicidal ideation with depressive symptoms, presence of anxiety, and high relational victimization scores attributing to 15% of the variance. Results of the 6-month follow-up support prior research suggesting high correlation between Major Depressive Disorder and suicidal ideation. However, there was no correlation found between levels of suicidal ideation and Generalized Anxiety Disorders.
Synthesis and characterization of multilayered BaTiO3/NiFe2O4 thin films
Authors: Bajac Branimir , Vukmirovic Jelena , Tokic Ivan , Ognjanovic Stevan , Srdic Vladimir
Published: April 2013

Presented research was focused on the fabrication of multiferroic thin film
structures, composed of ferrielectric barium titanate perovskite phase and
magnetostrictive nickel ferrite spinel phase. The applicability of different,
solution based, deposition techniques (film growth from solution, dip coating
and spin coating) for the fabrication of multilayered BaTiO3 /NiFe2O4 thin
films was investigated. It was shown that only spin coating produces films of
desired nanostructure, thickness and smooth and crackfree surfaces.
Identification of promising chemical systems for the synthesis of new materials structure types: An ab initio minimization data mining approach
Authors: Zagorac Dejan , Schön Johann , Jansen Martin
Published: April 2013

In this research we performed data exploring for binary compounds with
elements from groups V, IV-VI, and III-VII, with the goal to identify
chemical systems where the recently proposed ?5-5? structure type might be
experimentally accessible. Among others, TlF, SnO, SnS, SnSe, GeS, GeSe, PbO,
PbS, ZnO and ZnS, were chosen for the study. For each of these systems, a
local optimization on ab initio level with the LDA functional was performed
for the 5-5 structure type, plus other experimentally observed and
theoretically proposed structure types, for comparison. Afterwards, the
results were combined with earlier theoretical work involving the 5-5
structure in the earth alkaline metal oxides and the alkali metal halides. As
a result, we suggest the GeSe and the ZnO systems as the most suitable ones
for synthesizing the 5-5 structure type.
Does Mandatory IFRS Adoption Affect the Credit Ratings of Foreign Firms Cross-Listed in the U.S.?
Authors: Chan Ann Ling-Ching , Hsu Audrey Wen-hsin , Lee Edward
Published: April 2013

SYNOPSIS:

We examine whether the mandatory adoption of International Financial Reporting Standards (IFRS) affects the credit ratings of foreign firms cross-listed in the U.S. Consistent with the influence of accounting information quality on credit ratings that is established in the literature, we find significantly higher credit ratings among these cross-listed firms after IFRS. Furthermore, this effect is more pronounced among those from countries where there is a greater difference between previous domestic standards and IFRS, and from countries that had weaker legal enforcement and investor protection before the transition. Our findings are consistent with IFRS improving the transparency and creditworthiness of foreign firms cross-listed in the U.S. by reducing their information costs and risk for U.S. investors. The evidence implies that IFRS adoption in their home country could benefit firms that are already cross-listed or are seeking to cross-list in the U.S.

JEL Classifications: F30; G15; M41.
Comments by the Auditing Standards Committee of the Auditing Section of the American Accounting Association on International Standard on Auditing (ISA) 720 (Revised), The Auditor's Responsibilities Relating to Other Information in Documents Containing or Accompanying Audited Financial Statements and the Auditor's Report Thereon
Authors: Feng Nancy Chun , Pevzner Mikhail , Robertson Jesse , Yahya-Zadeh Massood
Published: April 2013

On November 14, 2012, the International Auditing and Assurance Standards Board (IAASB) solicited public comments on its exposure draft of the document entitled International Standard on Auditing (ISA) 720 (Revised), The Auditor's Responsibilities Relating to Other Information in Documents Containing or Accompanying Audited Financial Statements and the Auditor's Report Thereon. The four-month comment period ended on March 14, 2013. This commentary summarizes the contributors' views on this exposure draft.

Data Availability: The exposure draft and other related information are available at http://www.ifac.org/publications-resources/international-standard-auditing-isa-720-revised-auditor-s-responsibilities-re
Integration of multispectral face recognition and multi-PTZ camera automated surveillance for security applications
Authors: Chen Chung-Hao , Yao Yi , Chang Hong , Koschan Andreas , Abidi Mongi
Published: April 2013

Due to increasing security concerns, a complete security system should consist of two major components, a computer-based face-recognition system and a real-time automated video surveillance system. A computerbased face-recognition system can be used in gate access control for identity authentication. In recent studies, multispectral imaging and fusion of multispectral narrow-band images in the visible spectrum have been employed and proven to enhance the recognition performance over conventional broad-band images, especially when the illumination changes. Thus, we present an automated method that specifies the optimal spectral ranges under the given illumination. Experimental results verify the consistent performance of our algorithm via the observation that an identical set of spectral band images is selected under all tested conditions. Our discovery can be practically used for a new customized sensor design associated with given illuminations for an improved face recognition performance over conventional broad-band images. In addition, once a person is authorized to enter a restricted area, we still need to continuously monitor his/her activities for the sake of security. Because pantilt-zoom (PTZ) cameras are capable of covering a panoramic area and maintaining high resolution imagery for real-time behavior understanding, researches in automated surveillance systems with multiple PTZ cameras have become increasingly important. Most existing algorithms require the prior knowledge of intrinsic parameters of the PTZ camera to infer the relative positioning and orientation among multiple PTZ cameras. To overcome this limitation, we propose a novel mapping algorithm that derives the relative positioning and orientation between two PTZ cameras based on a unified polynomial model. This reduces the dependence on the knowledge of intrinsic parameters of PTZ camera and relative positions. Experimental results demonstrate that our proposed algorithm presents substantially reduced computational complexity and improved flexibility at the cost of slightly decreased pixel accuracy as compared to Chen and Wang’s method [18].
Shallow repeating seismic events under an alpine glacier at Mount Rainier, Washington, USA
Authors: Thelen Weston A. , Allstadt Kate , Angelis Silvio De , Malone Stephen D. , Moran Seth C. , Vidale John
Published: April 2013

We observed several swarms of repeating low-frequency (1–5 Hz) seismic events during a 3 week period in May–June 2010, near the summit of Mount Rainier, Washington, USA, that likely were a result of stick–slip motion at the base of alpine glaciers. The dominant set of repeating events (‘multiplets’) featured >4000 individual events and did not exhibit daytime variations in recurrence interval or amplitude. Volcanoes and glaciers around the world are known to produce seismic signals with great variability in both frequency content and size. The low-frequency character and periodic recurrence of the Mount Rainier multiplets mimic long-period seismicity often seen at volcanoes, particularly during periods of unrest. However, their near-surface location, lack of common spectral peaks across the recording network, rapid attenuation of amplitudes with distance, and temporal correlation with weather systems all indicate that ice-related source mechanisms are the most likely explanation. We interpret the low-frequency character of these multiplets to be the result of trapping of seismic energy under glacial ice as it propagates through the highly heterogeneous and attenuating volcanic material. The Mount Rainier multiplet sequences underscore the difficulties in differentiating low-frequency signals due to glacial processes from those caused by volcanic processes on glacier-clad volcanoes.