bluuebunny/crossref_metadata_2025 huggingface dataset:
Alliance Activity as a Dynamic Capability in the Face of a Discontinuous Technological Change
Authors: Anand Jaideep , Oriani Raffaele , Vassolo Roberto S.
Published: February 2010

Using a dynamic capabilities lens, this study examines how technological and complementary capabilities affect firms' abilities to enter emerging technologies. The empirical evidence from a sample of pharmaceutical firms entering the new biotech fields indicates that both technological and complementary capabilities potentially affect firms' entry into emerging technologies and entry mode. However, the results also show that capabilities in the traditional technology and the emerging technology have different effects. Firms with capabilities in the emerging technology are more likely to enter new technological fields and more likely to use internal development in doing so. Complementary capabilities also increase the rate of entry into emerging technological fields. However, capabilities in traditional technology are found to be unrelated to the propensity to enter new fields, and to the choice of entry mode. These results are consistent with insights from the literature on dynamic capabilities and evolutionary theory. We examine the implications of these results for literatures on strategic alliances and technological competition.
A rational model for maximizing the effects of therapeutic relationship regulation in personality disorders with poor metacognition and over‐regulation of affects
Authors: Dimaggio Giancarlo , Carcione Antonino , Salvatore Giampaolo , Semerari Antonio , Nicolò Giuseppe
Published: February 2010

Background.

The therapeutic relationship plays a key role in personality disorder (PD) psychotherapy. Some aspects of therapeutic relationship regulation appear important for treatment of PD clients, including those with constricted relational schemas, poor metacognition, and over‐regulation of affects described here.

Aim.

To propose a rational model for how and when to work on the therapeutic relationship by treating the underlying personality pathology.

Method.

Formalize a step‐by‐step procedure for performing operations such as validation of clients' experiences, creating a sense of sharedness, assessing the quality of the therapeutic relationship in order to prevent and repair ruptures in the alliance, self‐disclosing by the therapist, and metacommunication on the basis of clients' responses to treatment.

Conclusion.

We discuss the implications of this model for further research into the PD therapy process.
Knowledge Management: A Key Ingredient in Tackling Terrorism
Authors: Rogers Colin , Gravelle James
Published: February 2010

This article considers the way in which the police service in England and Wales and other agencies use intelligence and knowledge to combat the threat of terrorist activity. It focuses upon the application of intelligence and highlights the role of knowledge management, describing the process involved. It also critically analyses how intelligence is captured, stored, processed and shared, and suggests methods of improving the use of such intelligence to provide a more effective and efficient way of tackling terrorism and other serious, organised crime.
Nitriti come segni profetici: cavalli fatidici a Bisanzio (XI–XIV sec.)
Authors: Costanza Salvatore
Published: February 2010

In the later Byzantine age, historical sources mention many examples of prophecies concerning Chremetismomancy, the divination by horses' neighs. As far as we know, however, we have no earlier documents about this practice from ancient or from medieval Greece. Under the Komnenoi and Palaiologoi, to the contrary, important prophetic neighs are quoted by Anna Komnene, by Niketas Choniates and Nikephoros Gregoras. Wonders which were worked by neighing horses are of very great political consequence, relating to crucial moments such as an emperor's military victories, a prince's succession to the imperial throne or the deposition of a ruler. In Gregoras' Roman History, it is not a living animal responsable for the nocturnal neighs, but a painted one at a chapel in the palace. It is very interesting to examine these narrative plots and historical accounts, as they convey many informations about Byzantine society. In particular, the strong disposition for magic, even at top-level of the society, should be emphasized. The philomantic emperors par excellence are Manuel I Komnenos and Andronikos II Palaiologos, the author of a themation, an astrological interpretation of horses' neighs, together with his faithful Logo the tes Theodoros Metochites, an expert at astrology and hemerology. The advance of such divinatory practices in the late Byzantine centuries should be related to home instability and enemies' threats on the boundaries. Chremetismomantic omina clearly focus on this particular climate of terror and uncertainty which forms the ideal ground for any attempt to foretell the future. Therefore, these practices were no laughing matter for Byzantine writers and their readers: only Nicetas Choniates' shy irony may argue us out of believing this.
The perception of icons in the late Byzantine world: some evidence in a treasury inventory of Hagia Sophia
Authors: Hetherington Paul
Published: February 2010

In 1396 an inventory of the treasury of Hagia Sophia was commissioned. It was written by three educated laymen who all had experience of court culture, and they listed some 180 items. Their descriptions of the few icons that they listed is of interest for several reasons: they do not mention the date or period of the icons, nor their style, condition, size, donors or any inscriptions that they displayed. Their only way of describing them was by the title of the subject of each icon. This suggests that, at any rate for laymen, the subject of an icon was of overwhelming importance, and this factor alone was thought to be sufficient to identify an icon in an inventory of this kind.
Das Συναξάριον τιμημένου γαδάρου: Analyse, Ausgabe, Wörterverzeichnis
Authors: Moennig Ulrich
Published: February 2010

The 14th century Συναξάριον τοῦ τιμημένου Γαδάρου (in English: the Tale of the heroic donkey) could be described as an aitiological story. In medieval Greek there was a synonymous word, νικóν (nikón), which alternatively to the more common word γάδαρος (ghádharos) meant donkey. The word νικóν recalls the verb (nikó) and even reminds us of the homophonous participe derived from the same verb. The tale explains how the word νικóν came into being.

Due to a fatal error in the editio princeps by W. Wagner (Carmina Graeca medii aevi, 1874) the pointe of the Tale is not intellegible in the printed text. K. Tsantsanoglu in 1971 realised the problems of Wagner's edition, but his article did not lead to a re-evaluation of this fine piece of late-Byzantine literature.

The present article offers: a new edition of the Tale of the heroic donkey, based on a completely new reading of the single manuscripts that preserves it; a new reading of the texts, focussing on questions of rhetorics and literary genre; a full glossary, based on the new edition.
Methods for Determining the Solubility Parameter of Bitumen
Authors: Wang Tao , Zhang Yuzhen
Published: February 2010

A method of computing a one-dimensional solubility parameter (Hildebrand solubility parameter) was used by expressing the molar attraction constants and molar volumes on a “per carbon atom” basis. Besides, two experimental methods of testing three-dimensional solubility parameters (Hansen solubility parameters) of bitumen were used, namely, three-dimensional turbidimetric titration method and dissolution method. By comparing the solubility parameters of six bitumens determined by three different methods, the results show that the solubility parameters of six bitumens determined by the three-dimensional turbidimetric titration method have a wider range than solubility parameters determined by the other two methods. By comparing the solubility parameters determined by three different methods with compatibility evaluation results, the results show that the solubility parameters determined by the three-dimensional turbidimetric titration have the best accordance with compatibility evaluation results. The three-dimensional turbidimetric titration has satisfactory precision and accuracy to determine Hansen three-dimensional solubility parameters.
Polymorphism of isotypic series of homoleptic 1,2,3-triazolate MOFs [Ln(Tz*)3] containing the heavy lanthanides Gd–Lu: from open to dense frameworks of varying dimensionality
Authors: Rybak Jens-Christoph , Tegel Marcus , Johrendt Dirk , Müller-Buschbaum Klaus
Published: February 2010

Homoleptic MOF structures of the formulas 2
∞[Ln(Tz*)3] and 3
∞[Ln(Tz*)3], (Tz*)– = 1,2,3-triazolate anion, C2H2N3
–, Ln = Gd-Lu, were obtained by the reaction of the lanthanide metals with the aromatic heterocyclic amine 1H-1,2,3-triazole. The isotypic series of compounds are real polymorphs as they have identical constitution. The 2-dimensional MOF is formed at lower temperatures whereas formation of the 3-dimensional MOF requires higher temperatures, in some cases solvothermal reaction conditions. We therefore address them as low-temperature α-form and high-temperature β-form. The thermodynamically stable β-form exhibits high thermal stabilities regarding compounds that contain three neighboring nitrogen atoms in one organic ring, ranging up to 380 °C. Transition from α to β-form is accompanied by transformation from open to dense frameworks as only the α-form contains structural voids. This goes along with both an increase of dimensionality of the linkage from 2D to 3D and an increase of the density of the structures. The α-form adopts the AlCl3 structure, the β-form can be identified with a (10,3)-b net. Although no single crystals could be obtained for β-3
∞[Ln(Tz*)3], structure solution and reasonable refinement were successful from X-ray powder data. The crystal structure of α-2
∞[Ln(Tz*)3] was previously solved from single crystal data.
Amplification of the Gene for Isoleucyl–tRNA Synthetase Facilitates Adaptation to the Fitness Cost of Mupirocin Resistance inSalmonella enterica
Authors: Paulander Wilhelm , Andersson Dan I , Maisnier-Patin Sophie
Published: February 2010

Mutations that cause resistance to antibiotics in bacteria often reduce growth rate by impairing some essential cellular function. This growth impairment is expected to counterselect resistant organisms from natural populations following discontinuation of antibiotic therapy. Unfortunately (for disease control) bacteria adapt and improve their growth rate, often without losing antibiotic resistance. This adaptation process was studied in mupirocin-resistant (MupR) strains of Salmonella enterica. Mupirocin (Mup) is an isoleucyl–adenylate analog that inhibits the essential enzyme, isoleucyl–tRNA synthetase (IleRS). Mutations causing MupR alter IleRS and reduce growth rate. Fitness is restored by any of 23 secondary IleRS amino acid substitutions, 60% of which leave resistance unaffected. Evidence that increased expression of the original mutant ileS gene (MupR) also improves fitness while maintaining resistance is presented. Expression can be increased by amplification of the ileS gene (more copies) or mutations that improve the ileS promoter (more transcription). Some adapted strains show both ileS amplification and an improved promoter. This suggests a process of adaptation initiated by common amplifications and followed by later acquisition of rare point mutations. Finally, a point mutation in one copy relaxes selection and allows loss of defective ileS copies. This sequence of events is demonstrated experimentally. A better understanding of adaptation can explain why antibiotic resistance persists in bacterial populations and may help identify drugs that are least subject to this problem.
Fetal Exposure to Antidepressants and Normal Milestone Development at 6 and 19 Months of Age
Authors: Pedersen Lars Henning , Henriksen Tine Brink , Olsen Jørn
Published: February 2010

OBJECTIVE:

The goal was to investigate a possible association between exposure to antidepressants in utero and developmental milestones in early childhood.

METHODS:

Information on pregnancy exposures and developmental milestones at 6 and 19 months was obtained from the Danish National Birth Cohort. Of the eligible pregnant women, 415 used antidepressant medication, 489 reported depression with no medical treatment, and 81 042 reported no depression and no use of psychotropic medication.

RESULTS:

Children with second- or third-trimester exposure to antidepressants were able to sit 15.9 days (95% confidence interval [CI]: 6.8–25.0) and to walk 28.9 days (95% CI: 15.0–42.7) later than children of women not exposed to antidepressants but still were within the normal range of development. Fewer children with second- or third-trimester exposure to antidepressants were able to sit without support at 6 months of age (odds ratio: 2.1 [95% CI: 1.23–3.60]), and fewer were able to occupy themselves at 19 months of age (odds ratio: 2.1 [95% CI: 1.09–4.02]). None of the other milestones measured showed statistically significant associations with antidepressant exposure.

CONCLUSION:

The results of this study suggest a permanent or reversible effect of antidepressant exposure on fetal brain development, which may depend on the timing of exposure during pregnancy.
Desigualdades socioeconómicas en la utilización de servicios de salud bucal: estudio en escolares mexicanos de 6 a 12 años de edad
Authors: Medina-Solís Carlo Eduardo , Villalobos-Rodelo Juan José , Márquez-Corona María de Lourdes , Vallejos-Sánchez Ana Alicia , Portillo-Núñez Carlos López , Casanova-Rosado Alejandro José
Published: February 2010

El objetivo del estudio fue evaluar la asociación entre diversos indicadores socioeconómicos y la utilización de servicios de salud bucal. Se realizó un estudio transversal en 3.048 escolares. La variable utilización de servicios de salud bucal y las variables sociodemográficas y socioeconómicas se colectaron a través de un cuestionario dirigido a las madres. Para determinar las necesidades de salud se realizó un examen clínico bucal a los niños. Las asociaciones ajustadas fueron evaluadas con regresión logística politómica. Las variables asociadas a servicios preventivos y curativos fueron mayor edad, mayor frecuencia de cepillado y menor edad al inicio de cepillado dental, tener seguro público o privado, y mejor nivel socioeconómico. Además, sólo para los servicios preventivos, también se asoció estar inscrito en una escuela privada, y sólo para los servicios curativos, la posesión de automóvil y tener necesidades de salud bucal entre moderadas y muy altas. Los resultados sugieren la existencia de desigualdades socioeconómicas en la utilización de servicios de salud bucal en niños mexicanos.
Associação entre consumo de refrigerantes, sucos e leite, com o índice de massa corporal em escolares da rede pública de Niterói, Rio de Janeiro, Brasil
Authors: Nogueira Fernanda de Albuquerque Melo , Sichieri Rosely
Published: February 2010

Avaliou-se a associação entre o consumo de refrigerantes, sucos e leite, com o índice de massa corporal (IMC) em 1.423 estudantes, entre 9 e 16 anos, de escolas públicas de Niterói, Rio de Janeiro, Brasil. O consumo de bebidas foi avaliado por meio do recordatório alimentar de 24 horas e questionário de freqüência de consumo alimentar. Peso e estatura foram coletados para o cálculo do IMC. As análises de regressão linear foram estratificadas por sexo e ajustadas por atividade física, idade e efeito do conglomerado (classes). Verificou-se associação positiva entre freqüência de consumo de refrigerante e idade (p = 0,05) e negativa entre consumo de leite e idade (p = 0,004). Apenas para as meninas, o IMC associou-se positivamente com o consumo de sucos (β = 0,02; p = 0,03). Para as outras bebidas não foram encontradas associações entre IMC e freqüência usual de consumo. O consumo de refrigerantes e sucos representou cerca de 20% do total de energia média consumida diariamente. Os resultados indicam que esforços para reduzir a ingestão de energia por meio de bebidas devem enfatizar também os sucos.
Terrestrial phosphorus limitation: mechanisms, implications, and nitrogen–phosphorus interactions
Authors: Vitousek Peter M. , Porder Stephen , Houlton Benjamin Z. , Chadwick Oliver A.
Published: February 2010

Nutrient limitation to primary productivity and other biological processes is widespread in terrestrial ecosystems, and nitrogen (N) and phosphorus (P) are the most common limiting elements, both individually and in combination. Mechanisms that drive P limitation, and their interactions with the N cycle, have received less attention than mechanisms causing N limitation. We identify and discuss six mechanisms that could drive P limitation in terrestrial ecosystems. The best known of these is depletion‐driven limitation, in which accumulated P losses during long‐term soil and ecosystem development contribute to what Walker and Syers termed a “terminal steady state” of profound P depletion and limitation. The other mechanisms are soil barriers that prevent access to P; transactional limitation, in which weathering of P‐containing minerals does not keep pace with the supply of other resources; low‐P parent materials; P sinks; and anthropogenic changes that increase the supply of other resources (often N) relative to P. We distinguish proximate nutrient limitation (which occurs where additions of a nutrient stimulate biological processes, especially productivity) from ultimate nutrient limitation (where additions of a nutrient can transform ecosystems). Of the mechanisms that drive P limitation, we suggest that depletion, soil barriers, and low‐P parent material often cause ultimate limitation because they control the ecosystem mass balance of P. Similarly, demand‐independent losses and constraints to N fixation can control the ecosystem‐level mass balance of N and cause it to be an ultimate limiting nutrient.
Are forested buffers an effective conservation strategy for riparian fauna? An assessment using meta‐analysis
Authors: Marczak Laurie B. , Sakamaki Takashi , Turvey Shannon L. , Deguise Isabelle , Wood Sylvia L. R. , Richardson John S.
Published: February 2010

Historically, forested riparian buffers have been created to provide protection for aquatic organisms and aquatic ecosystem functions. Increasingly, new and existing riparian buffers are being used also to meet terrestrial conservation requirements. To test the effectiveness of riparian buffers for conserving terrestrial fauna, we conducted a meta‐analysis using published data from 397 comparisons of species abundance in riparian buffers and unharvested (reference) riparian sites. The response of terrestrial species to riparian buffers was not consistent between taxonomic groups; bird and arthropod abundances were significantly greater in buffers relative to unharvested areas, whereas amphibian abundance decreased. Edge‐preferring species were more abundant in buffer sites than reference sites, whereas species associated with interior habitat were not significantly different in abundance. The degree of buffer effect on animal abundance was unrelated to buffer width; wider buffers did not result in greater similarity between reference and buffer sites. However, responses to buffer treatment were more variable in buffers <50 m wide, a commonly prescribed width in many management plans. Our results indicate that current buffer prescriptions do not maintain most terrestrial organisms in buffer strips at levels comparable to undisturbed sites.
Using occupancy models to understand the distribution of an amphibian pathogen, Batrachochytrium dendrobatidis
Authors: Adams Michael J. , Chelgren Nathan D. , Reinitz David , Cole Rebecca A. , Rachowicz Lara J. , Galvan Stephanie , McCreary Brome , Pearl Christopher A. , Bailey Larissa L. , Bettaso Jamie , Bull Evelyn L. , Leu Matthias
Published: February 2010

Batrachochytrium dendrobatidis is a fungal pathogen that is receiving attention around the world for its role in amphibian declines. Study of its occurrence patterns is hampered by false negatives: the failure to detect the pathogen when it is present. Occupancy models are a useful but currently underutilized tool for analyzing detection data when the probability of detecting a species is <1. We use occupancy models to evaluate hypotheses concerning the occurrence and prevalence of B. dendrobatidis and discuss how this application differs from a conventional occupancy approach. We found that the probability of detecting the pathogen, conditional on presence of the pathogen in the anuran population, was related to amphibian development stage, day of the year, elevation, and human activities. Batrachochytrium dendrobatidis was found throughout our study area but was only estimated to occur in 53.4% of 78 populations of native amphibians and 66.4% of 40 populations of nonnative Rana catesbeiana tested. We found little evidence to support any spatial hypotheses concerning the probability that the pathogen occurs in a population, but did find evidence of some taxonomic variation. We discuss the interpretation of occupancy model parameters, when, unlike a conventional occupancy application, the number of potential samples or observations is finite.
Biodiversity conservation in the era of biofuels: risks and opportunities
Authors: Fletcher Robert J , Robertson Bruce A , Evans Jason , Doran Patrick J , Alavalapati Janaki RR , Schemske Douglas W
Published: February 2010

Growing demand for alternative energy sources has contributed to increased biofuel production, but the effects on biodiversity of land‐use change to biofuel crops remain unclear. Using a meta‐analysis for crops being used or considered in the US, we find that vertebrate diversity and abundance are generally lower in biofuel crop habitats relative to the non‐crop habitats that these crops may replace. Diversity effects are greater for corn than for pine and poplar, and birds of conservation concern experience greater negative effects from corn than species of less concern. Yet conversion of row‐crop fields to grasslands dedicated to biofuels could increase local diversity and abundance of birds. To minimize impacts of biofuel crops on biodiversity, we recommend management practices that reduce chemical inputs, increase heterogeneity within fields, and delay harvests until bird breeding has ceased. We encourage research that will move us toward a sustainable biofuels economy, including the use of native plants, development of robust environmental criteria for evaluating biofuel crops, and integrated cost–benefit analysis of potential land‐use change.
Gas Reserves Estimation in Resource Plays
Authors: Lee W. J. , Sidle R. E.
Published: February 2010

The petroleum industry's lack of understanding of physical properties and the physics controlling production from many important resource plays limits its ability to model and forecast with confidence production and reserves from these resources. While measurement technology and modeling accuracy is improving, the industry is often forced to resort to empirical methods that lack the usual validation required for high confidence in results. This paper analyzes some of the procedures in common use for forecasting and identifies key strengths and limitations of the techniques.
Development Update for an Emerging Shale Gas Giant Field—Horn River Basin, British Columbia, Canada
Authors: Reynolds M. M. , Munn D. L.
Published: February 2010

The Horn River Basin covers an estimated 3 million acres in a remote and difficult to access area of northern British Columbia. A number of Operators have experimental projects in the area, using various drilling and completion techniques, in order to evaluate the shale reservoir, gas in place, and productivity; moving towards commercial projects. The Devonian age shales of the Horn River Basin have been compared to the Barnett Shale of the Fort Worth Basin, in terms of reservoir quality, productivity and recovery factors.

This paper will review the following important aspects of the Horn River shale area: History of the play;General review of the Geology, reservoir properties, thickness, gas content, gas in place, permeability, etc.;Emerging drilling and completions techniques, well construction, stimulation practices, fracture diagnostics, logistical problems;Production tests, well initial productivities, and longer term production forecasts, estimated recovery factors;Production and Operations challenges;Development costs and economics;Future development hurdles, what is needed to make this play commercial?
Using Microseisms to Monitor Hydraulic Fractures in the Bakken Formation of North Dakota
Authors: Forrest Gary S. , Olsen Thomas N. , Kazantsev Aleksey , Dombrowski Timothy J. , Gomez Ernest , Rowe Wayne
Published: February 2010

The Mississippian-Devonian Bakken Formation is a relatively tight mixed carbonate – clastic sequence in the Williston Basin of North Dakota. Although production can exceed 1000 BOPD, hydraulic fracturing is necessary to induce economic production. In late 2007 seven (7) operators along with Schlumberger formed a consortium for the purpose of applying the best available technologies to examine the geologic factors and the drilling and completion principles that affect production. As part of this, three (3) horizontal wells (each 4000 feet in length) were drilled 1500 feet apart into the Middle Bakken Member. Schlumberger positioned an array of 16 triaxial geophones, spaced 100 feet apart, in the middle lateral (Nesson State 42X-36) to monitor the microseismic activity during the hydraulic fracturing of the two (2) outside wells. Different hydraulic fracturing methods were applied in each stage; ranging from a single treatment in the northern lateral (Nesson State 41X-36) to a six (6) staged treatment with swell packers in the southern lateral (Nesson State 44X-36). The microseismic events were studied in the context of our geologic understanding of the area, comparison to the distributions of radioactive and chemical tracers and a reservoir simulation to develop a robust interpretation of effectiveness of the hydraulic fracture treatments. In addition to the microseismic monitoring conducted by Schlumberger, three other microseismic monitoring arrays were installed and monitored. The results of the various monitoring efforts varied dramatically and these differences are worthy of examination.
Less Sand May Not Be Enough
Authors: Curry M. , Maloney T. , Woodroof R. , Leonard R.
Published: February 2010

Since the first modern Marcellus completion in Washington County, Pennsylvania in 2004, over 2000 Marcellus wells (horizontal and vertical) have either been permitted or drilled through October 2009 in the Appalachian Basin. The Marcellus play has become one of the most widely discussed plays in the nation, with numerous operators drilling and completing wells in Pennsylvania, West Virginia, Ohio, and New York. While the play is still in its infancy, reported production rates and reserves compare very favorably to other established North American shale plays.

The play's wide geographic range has led to numerous and varied completion schemes being utilized. One primary concern has been determining the optimal size and type of stimulation treatment for a given area. One premise has been that equivalent EUR's should be less of an optimization determinant than production curves, especially early-time production, as revenue generated closer in time to capital spent is worth more than far-into-the-future revenue, and thus completions that lead to high initial production rates are more desirable for optimum rates of return and improved net present values. This paper will describe an unsuccessful attempt to reduce the size (primarily proppant volume used) of the frac treatments, thus lowering the overall completion costs, without sacrificing higher-rate, early-time production. The ultimate conclusion was that a substantial reduction in proppant volume, even though it was replaced with additional fluid volume, had a detrimental effect on fracture volume created, early-time production, and EUR. As this optimization process continues, some wells like the reduced sand volume wells discussed in this paper will require restimulation to maximize overall fracture network creation. Two successful horizontal shale refracture stimulations will also be described in this paper.
Integration of Microseismic and Other Post-Fracture Surveillance With Production Analysis: A Tight Gas Study
Authors: Clarkson C. R. , Beierle J. J.
Published: February 2010

Quantitative production analysis of tight gas reservoirs has historically been a challenge due to complex reservoir characteristics (ex. lateral and vertical heterogeneity, stress-sensitivity of permeability and porosity), induced hydraulic fracture properties in vertical wells (ex. multi-phase flow, conductivity changes, complex fracture geometries), operational complexities (ex. variable back-pressure, liquid-loading) and data quality (infrequent rate or flowing pressure reporting). All of these challenges conspire to make extraction of reservoir (kh and OGIP) and hydraulic fracture properties (xf and fracture conductivity) soley from production/flowing pressure data difficult, often resulting in non-unique answers. In recent history, there has been the added complication that tight gas (and most recently shale gas) reservoirs are now being exploited with horizontal wells, often stimulated using multiple hydraulic fracture stages, which imparts greater complexity on the analysis. Flow regime identification, which is critical to the correct analysis, is more complicated than ever owing to the number of possible flow regimes encountered in such wells.

A case study is presented in which it is demonstrated that modern post-fracture surveillance data, such as microseismic and post-frac production logging, aids in both model identification and model calibration, which is critical to the analysis of hydraulically-fractured horizontal wells completed in tight gas formations. A workflow is presented in which offset vertical wells (to the horizontal wells) are first analyzed to obtain estimates of kh and hydraulic fracture properties, followed by commingled-stage and single-stage production analysis of the multi- (transverse) hydraulic fracture horizontal wells. Microseismic data is incorporated into the analysis of the horizontal wells to 1) understand the orientation and degree of complexity of the induced hydraulic fractures and 2) constrain interpretations of effective hydraulic fracture lengths from production data analysis. It is also demonstrated that once the commingled stage analysis of the horizontal wells is completed, the total interpreted effective hydraulic fracture half-length may be allocated amongst the stages using a combination of production logs and tracer logs.

The primary contribution of the current work is the presentation of workflows, emphasizing the integration of various data sources, to improve production analysis of multi-frac’d horizontal wells completed in tight gas formations. In addition to the workflows, it is shown that a combination of advanced production analysis approaches, including methods analogous to classic pressure transient analysis, production type-curve matching and simulation, may be necessary to arrive at a unique analysis.
Surface Microseismic Monitoring of Slick Water and Nitrogen Fracture Stimulations, Arkoma Basin, Oklahoma
Authors: Hall Morris , Kilpatrick Jo Ellen
Published: February 2010

Abstract

Surface based microseismic monitoring was performed to assess the effectiveness of slick-water and nitrogen fracture stimulations in a horizontal well with a 3500' lateral drilled in the Arkoma Basin of Oklahoma. Water production from this shale as well as the located events from the microseismic monitoring suggested the fracs were not contained in the target formation and contacted foreign water. The observed distribution of microseismic events suggested that planar fractures were created with varying complexity. The azimuths of the produced trends suggested that a strong influence from the pre-existing natural fractures directed the induced fractures. A direct comparison of the slick-water treatment to the nitrogen treatment revealed multiple advantages with the latter, such as more in-zone events, more energy per event, and more complexity in resulting fractures.

Introduction

The area monitored is located in the Arkoma Basin of Oklahoma, an area where the basin tectonics are inactive, but the weather is not. The surface array used to perform the surface monitoring of the slick-water and nitrogen treatments was designed to locate induced microseismic events by beamforming. The array consisted of 1078 stations of 12 geophones laid out in a radial pattern around the treatment well (Figure1). Although the treatments were two months apart, the array geometry was identical with the exception of removal of 11 stations from the array during the nitrogen treatment. The geophones were buried to a depth of one foot to maximize the signal to noise ratio by reducing the interference of the frequent seasonal rainfall. Cultural sources of noise such as traffic and inherent pad noises were taken into account by surface array design and seismic processing.
Effects of Manure and Cultivation on Carbon Dioxide and Nitrous Oxide Emissions from a Corn Field under Mediterranean Conditions
Authors: Heller Hadar , Bar‐Tal Asher , Tamir Guy , Bloom Paul , Venterea Rodney T. , Chen Dong , Zhang Yi , Clapp C. Edward , Fine Pinchas
Published: February 2010

The use of organic residues as soil additives is increasing, but, depending on their composition and application methods, these organic amendments can stimulate the emissions of CO2 and N2O. The objective of this study was to quantify the effects of management practices in irrigated sweet corn (Zea mays L.) on CO2 and N2O emissions and to relate emissions to environmental factors. In a 3‐yr study, corn residues (CR) and pasteurized chicken manure (PCM) were used as soil amendments compared with no residue (NR) under three management practices: shallow tillage (ST) and no tillage (NT) under consecutive corn crops and ST without crop. Tillage significantly increased (P < 0.05) CO2 and N2O fluxes in residue‐amended plots and in NR plots. Carbon dioxide and N2O fluxes were correlated with soil NH4 concentrations and with days since tillage and days since seeding. Fluxes of CO2 were correlated with soil water content, whereas N2O fluxes had higher correlation with air temperature. Annual CO2 emissions were higher with PCM than with CR and NR (9.7, 2.9, and 2.3 Mg C ha−1, respectively). Fluxes of N2O were 34.4, 0.94, and 0.77 kg N ha−1 yr−1 with PCM, CR, and NR, respectively. Annual amounts of CO2–C and N2O–N emissions from the PCM treatments were 64 and 3% of the applied C and N, respectively. Regardless of cultivation practices, elevated N2O emissions were recorded in the PCM treatment. These emissions could negate some of the beneficial effects of PCM on soil properties.
Response of Maize Yield, Nitrate Leaching, and Soil Nitrogen to Pig Slurry Combined with Mineral Nitrogen
Authors: Yagüe María R. , Quílez Dolores
Published: February 2010

The application of pig (Sus scrofa) slurry (PS) is a common fertilization practice that may affect nitrate concentrations and loads in drainage and receiving water bodies. To protect water resources, many agricultural areas are being designated as vulnerable to nitrate contamination, and there is a need for scientific data aiming at reducing nitrate exports from these vulnerable zones by optimizing N fertilization strategies. The objective of this work, conducted in drainage lysimeters in a 4‐yr monoculture maize (Zea mays L.) crop, is to assess the effects of four fertilization strategies combining PS (30, 60, 90, and 120 t ha−1) and mineral N on yield, changes in soil mineral N, and concentration and mass of nitrate in drainage waters. Grain yield was not affected by treatments in the four experimental years, nor was the soil mineral N at the end of the experiment. Effects of fertilization strategies on nitrate concentration and mass in drainage waters were detected only after 3 yr of repeated PS applications. The mass of nitrate leached over the 4 yr was positively related to the total amount of N applied, either organic or mineral. In year 2003, precipitation in spring reduced N availability for the crop in treatments with rates ≥ 60 t PS ha−1 The N‐budget revealed that the transport pathways for 25% of N inputs to the system are unknown. The presowing application of pig slurry at 30 t ha−1 complemented with mineral N at side‐dressing, was the most efficient from an environmental standpoint (4‐yr average of 145 kg grain yield kg−1 N leached).
Effect of Turfgrass Establishment Practices and Composted Biosolids on Water Quality
Authors: Schnell Ronnie W. , Vietor Donald M. , Munster Clyde L. , White Richard H. , Provin Tony L.
Published: February 2010

Land application of composted municipal biosolids (CMB) enhances soil physical properties and turf establishment. Yet large, volume‐based rates of CMB can increase nonpoint source losses of sediment and nutrients from urban soils to surface waters. The objectives were (i) to compare runoff losses of sediment, N, P, and organic C among contrasting establishment treatments for bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy, var. Tifway] and (ii) to evaluate relationships between runoff and soil measurements of N, P, and organic C. Three replications of seven establishment treatments were installed on an excavated slope (8.5%) under field conditions. Five treatments comprised sod transplanted from Tifway bermudagrass grown with and without CMB on soil with and without incorporation of CMB. Two other treatments were composed of Tifway sprigged in soil with and without CMB. Runoff from seven natural rain events was channeled into collection tanks for sampling and analysis. Runoff concentrations and mass loss of dissolved P and organic C forms were greater for CMB‐amended sod than for sprigs planted in soil with or without CMB or treatments comprising sod established without CMB. In addition, a linear relationship (R2 = 0.87) was observed between water extractable soil P of sodded and sprigged treatments and concentrations and mass losses of dissolved P in runoff. Transplanted sod reduced sediment loss compared with sprigged treatments and incorporation of CMB reduced sediment loss from sprigged treatments. Incorporation of CMB within soil on which sod grown without CMB was transplanted proved the best option for achieving benefits of CMB while reducing nutrient runoff loss compared to sod transplanted from Tifway grown with CMB.
Different Indices to Express Biodegradability in Organic Solid Wastes
Authors: Ponsá Sergio , Gea Teresa , Sánchez Antoni
Published: February 2010

Respiration indices are suggested in literature as the most suitable stability determination and are proposed as a biodegradability measure in this work. An improved dynamic respiration index methodology is described in this work. This methodology was applied to 58 samples of different types of waste including municipal solid wastes and wastewater sludge, both raw materials and samples collected in a mechanical‐biological treatment plant at different stages of biodegradation. The information obtained allowed to establish a qualitative classification of wastes in three categories: highly biodegradable, moderately biodegradable, and wastes of low biodegradability. Results were analyzed in terms of long and short‐term indices and index expression: dynamic respiration indices expressed as average oxygen uptake rate (mg O2 g−1 dry matter [DM] h−1) at 1 and 24 h of maximum activity (DRI1h, DRI24h); and cumulative oxygen consumption in 24 h of maximum activity and 4 d (AT24h, AT4). The statistical comparison of indices and wastes is also presented. Raw sludge presented the highest biodegradability followed by the organic fraction of municipal solid waste and anaerobically digested sludge. All indices correlated well but different correlations were found for the different wastes analyzed. The information in the dynamic respiration profile allows for the calculation of different indices that provide complementary information. The combined analysis of DRI24h and AT4 is presented here as the best tool for biodegradable organic matter content characterization and process requirements estimation.
Fallow Effects on Soil Carbon and Greenhouse Gas Flux in Central North Dakota
Authors: Liebig M. A. , Tanaka D. L. , Gross J. R.
Published: February 2010

The inclusion of cover crops during fallow (i.e., green fallow) may mitigate greenhouse gas (GHG) emissions from dryland cropping systems. An investigation was conducted to quantify the effects of chemical and green fallow on soil organic C (SOC) and CO2, CH4, and N2O flux within spring wheat (Triticum aestivum L.)–fallow (chemical fallow) and spring wheat–safflower (Carthamus tinctorius L.)–rye (Secale cereale L.) (green fallow) under no‐till management in west‐central North Dakota. Using static chamber methodology, flux measurements were made during 19 mo of the fallow period of each cropping system. Soil samples collected before initiation of flux measurements indicated no difference in SOC in the surface 10 cm between cropping systems. Additionally, differences in gas flux between cropping systems were few. Emission of CO2 was greater under green fallow than chemical fallow during spring thaw until the termination of rye (P = 0.0071). Uptake of atmospheric CH4 was the dominant exchange process during the evaluation period, and was significantly (P = 0.0124) greater under chemical fallow (−2.7 g CH4–C ha−1 d−1) than green fallow (−1.5 g CH4–C ha−1 d−1) following the termination of rye. Cumulative fluxes of CO2, CH4, and N2O did not differ between the chemical‐ and green‐fallow phases during the 19‐mo period (P = 0.1293, 0.2629, and 0.9979, respectively). The results from this evaluation suggest there was no net GHG benefit from incorporating a rye cover crop during the fallow phase of a dryland cropping system under no‐till management.
Hierarchical, Bimodal Model for Gas Diffusivity in Aggregated, Unsaturated Soils
Authors: Resurreccion Augustus C. , Moldrup Per , Kawamoto Ken , Hamamoto Shoichiro , Rolston Dennis E. , Komatsu Toshiko
Published: February 2010

The soil gas diffusion coefficient (Dp) and its dependency on soil air content, ε, and tortuosity–connectivity of the air‐filled pore networks control the transport and fate of gaseous‐phase contaminants in variably saturated soil. The bimodality in pore size distribution of structured soil often yields a variation of Dp with ε in the intraaggregate pore region that is distinctly different from that in the interaggregate region. Data imply a highly nonlinear behavior of soil gas diffusivity, Dp(ε)/Do (where Do is the gas diffusion coefficient in free air), in the interaggregate region of aggregated soils similar to that of structureless soils with a unimodal pore size distribution, probably due to diffusion‐limiting effects by connected water films at low ε. In contrast, for the intraaggregate region, we show that the impedance factor F* (= Dp/εDo) and tortuosity factor T [= (1/F*)1/2] are approximately constant for most soil media. We suggest a typically well‐defined separation between the two pore regions at the minimum for the pore connectivity factor X* [= log(Dp/Do)/log(ε)], at which point the interaggregate pores are devoid of water while the intraaggregate pore region is water saturated. Based on this, a hierarchical two independent region (TIR) Dp/Do model was developed by applying a cumulative series of Buckingham–Currie power‐law functions, FεX A nonlinear, water‐content‐dependent expression for F best described the measured Dp/Do in the interaggregate region, while constant F (around 0.5) and X (around 1) generally sufficed for the intraaggregate region. The TIR model better predicted gas diffusivities for both aggregate fractions and highly structured soils across the entire range of moisture conditions with RMSE reduced by two to five times compared with traditional predictive Dp(ε)/Do models.
Greenhouse Gas Mitigation Economics for Irrigated Cropping Systems in Northeastern Colorado
Authors: Archer David W. , Halvorson Ardell D.
Published: February 2010

Recent soil and crop management technologies have potential for mitigating greenhouse gas emissions; however, these management strategies must be profitable if they are to be adopted by producers. The economic feasibility of reducing net greenhouse gas emissions in irrigated cropping systems was evaluated for 5 yr on a Fort Collins clay loam soil (a fine‐loamy, mixed, superactive, mesic Aridic Haplustalf). Cropping systems included conventional tillage continuous corn (Zea mays L.) (CT‐CC), no‐till continuous corn (NT‐CC), and no‐till corn–bean (NT‐CB) including 1 yr soybean [Glycine max (L.) Merr.] and 1 yr dry bean (Phaseolus vulgaris L.). The study included six N fertilization rates ranging from 0 to 246 kg ha−1 Results showed highest average net returns for NT‐CB, exceeding net returns for NT‐CC and CT‐CC by US$182 and US$228 ha−1, respectively, at economically optimum N fertilizer rates. Net global warming potential (GWP) generally increased with increasing N fertilizer rate with the exception of NT‐CC, where net GWP initially declined and then increased at higher N rates. Combining economic and net GWP measurements showed that producers have an economic incentive to switch from CT‐CC to NT‐CB, increasing annual average net returns by US$228 ha−1 while reducing annual net GWP by 929 kg CO2 equivalents ha−1 The greatest GWP reductions (1463 kg CO2 equivalents ha−1) could be achieved by switching from CT‐CC to NT‐CC while also increasing net returns, but the presence of a more profitable NT‐CB alternative means NT‐CC is unlikely to be chosen without additional economic incentives.
Effects of Land Use and Vegetation Cover on Soil Temperature in an Urban Ecosystem
Authors: Savva Yulia , Szlavecz Katalin , Pouyat Richard V. , Groffman Peter M. , Heisler Gordon
Published: February 2010

Human activity has changed land surfaces by converting native ecosystems to urban and agricultural land uses. This conversion has caused increases in air and soil temperatures that influence soil C and N cycling. Efforts to model changes in soil temperature resulting from urban land use change have not accounted for changes in both plant cover and land use and thus fail to produce accurate predictions at high‐resolution spatial and temporal scales. We measured average daily soil temperature at a 10‐cm depth at urban and rural forest and grassland sites for 8 yr in the Baltimore, MD, metropolitan area and developed a model of the average daily soil temperature that accounts for two vegetation and two land use types. Average annual soil temperature was higher in urban than rural sites under both turfgrass (15.0°C vs. 13.5°C) and forest (12.6°C vs. 12.2°C). The application of climate‐change scenarios predicted by general circulation models to our soil temperature model suggested that the highest increases in mean soil temperatures will occur in August, September, February, and March, and will range from 1.2 to 2.0°C, while air temperature is predicted to change from 3.4 to 5.6°C between 2070 and 2099. The model can be used to predict the average daily soil temperature in the Baltimore area for sites with similar hydrologic and soil conditions, i.e., remote from the shoreline and characterized by loamy soils.