bluuebunny/crossref_metadata_2025 huggingface dataset:
Patients' Perspectives on Cardiac Rehabilitation, Lifestyle Change and Taking Medicines: Implications for Service Development
Authors: White Simon , Bissell Paul , Anderson Claire
Published: February 2010

Objectives

Cardiac rehabilitation programmes offer eligible coronary heart disease patients information on lifestyle modification and medicines. Our aim was to understand patients' perspectives on these topics.

Methods

In-depth qualitative interviews were conducted and audiotaped with 15 patients approximately three months after hospital discharge, after they had completed a hospital-based cardiac rehabilitation programme. Repeat interviews with ten patients explored whether their perspectives had changed when interviewed again approximately nine months later.

Results

Patients tended to talk about the exercise component of cardiac rehabilitation and only talk about the information provision component when prompted, which suggested they viewed the programme as being primarily about exercise. They seemed to have little subsequent contact with health services, except routine six-monthly check-ups for their coronary heart disease. Unmet information needs were common, especially about medicines. Nevertheless, all patients reported continuing to take cardiac medicines, but tended to only maintain changes to aspects of lifestyle perceived as causes of coronary heart disease, rather than viewing lifestyle recommendations as standards to achieve.

Conclusion

Ensuring that individual patients' information needs about medicines and lifestyle are adequately met remains a key focus for cardiac rehabilitation development. Key aspects include individualizing information and actively seeking and responding to patients' needs during and after cardiac rehabilitation.
Relationship Duration and Returns to Brokerage in the Staffing Sector
Authors: Bidwell Matthew , Fernandez-Mateo Isabel
Published: February 2010

We examine how long-term relationships affect brokers' returns, using project-level pricing data from an information technology staffing firm. We argue that long-term relationships between brokers and their counterparties affect both acquisition of private information and bargaining power, helping brokers to create and capture economic value. The results show that the staffing firm is able to charge a higher price and capture a higher proportion of that price when it has a long-term relationship with the worker. We also show that the staffing firm's ability to generate returns from its relationships is constrained when the brokered parties (worker and client firm) have a long-term relationship with each other. We discuss the implications of these findings for the study of market brokerage and long-term exchange relationships.
Leukocyte, neutrophil, immature granulocyte counts and interleukin-6 are superior to procalcitonin, C-reactive protein and delta-He for detection of mild inflammation: data from marathon runners producing mild systemic inflammation visible immediately after the run / Leukozyten, Neutrophile, unreife Granulozyten und Interleukin-6 sind zum Nachweis geringgradiger Entzündungen Procalcitonin, C-reaktivem Protein und Delta-He überlegen: Ergebnisse aus einer Untersuchung von Marathonläufern
Authors: Weimann Andreas , Lun Andreas , Lun Sebastian , Zimmermann Mathias , Borges Adrian C. , Ziebig Reinhard , Gonzalez Jose B. , Munoz Saravia Silvia Gilka , Knebel Fabian , Schroeckh Sabrina , Schimke Ingolf
Published: February 2010

Immature granulocytes (IGs) and differences between reticulocyte and erythrocyte haemoglobin content (delta-He) are now available as modern parameters on routine haematology analysers for detecting inflammation. Are these markers more suitable to detect mild inflammation when compared with traditional inflammation markers such as leukocyte count, C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6) or diverse leukocyte surface molecules mainly used in research programs? To answer this question, a marathon race was used as a model of mild inflammation. Full blood counts, CRP, PCT, IL-6, expression of surface molecules on granulocytes, monocytes and lymphocytes were measured before and immediately after the race (inflammatory state) and were compared with each other. A further blood sample was taken after a 10-day rest. In the inflammatory state leukocytes, neutrophil counts and IL-6 concentration were considerably increased compared with basic conditions. Diagnostic sensitivity and specificity came up to 100%. CRP was not increased and delta-He did not drop to negative values, as it occurs in severe inflammation. Leukocyte surface molecules were able to indicate a mild inflammatory state induced by the marathon race, but these markers did not achieve the same discriminatory power when compared with IL-6 levels or neutrophil count. In conclusion, leukocytes, neutrophils and IG counts as well as IL-6 levels are the best indicators in a mild inflammation model similar to a marathon race.
Hyperbilirubinämie und transkutane Bilirubinbestimmung1 / Hyperbilirubinemia and transcutaneous bilirubinometry
Authors: El-Beshbishi Samar N. , Shattuck Karen E. , Mohammad Amin A. , Petersen John R.
Published: February 2010

Hintergrund: Ein Ikterus (Hyperbilirubinämie) tritt bei Neugeborenen häufig auf. Der Verlauf ist in den meisten Fällen benigne, doch eine schwere Hyperbilirubinämie kann zu einem Kernikterus führen, der bei frühzeitiger Erkennung und angemessener Therapie der Hyperbilirubinämie vermeidbar ist.

Inhalt: In dieser Übersichtsarbeit werden der Icterus neonatorum sowie die Anwendung der transkutanen Bilirubinbestimmung (TcB) zur Identifikation von Neugeborenen mit einem Risiko für eine schwere Hyperbilirubinämie diskutiert. Neben angemessenen Verlaufsuntersuchungen erfordert dieses Verfahren eine Interpretation der Ergebnisse entsprechend dem Risikolevel anhand eines Nomogramms, das die Bilirubinkonzentration in Abhängigkeit vom Alter des Neugeborenen in Stunden angibt. Untersucht wurden auch die potenziellen Auswirkungen der TcB-Bestimmung auf den klinischen Verlauf sowie die Limitationen der Methode.

Zusammenfassung: Die TcB-Bestimmung ist eine praktikable Option für das Neugeborenenscreening auf klinisch relevante Hyperbilirubinämien. Wenn sich für ein Neugeborenes ein erhöhtes Risiko für eine klinisch relevante Hyperbilirubinämie ergibt, sollte die Gesamtbilirubinkonzentration im Serum bestimmt werden. Eine externe Qualitätssicherung zur Erfassung von Messfehlern und von Schulungsdefiziten der Anwender sollte Teil jedes TcB-Monitoring-Programms sein.
At the edge of covalency: metallic nanotubes, low-dimensional metals and clusters
Authors: Ruck Michael
Published: February 2010

One of the main classifications of materials uses the categories of metals, semiconductors and insulators. However, the boundaries are vague. In so-called confined metals the mobility of conduction electrons is restricted by at least one of the following circumstances: (a) Tendency towards electronic localization in covalent bonds, on ions or in lone-pairs (chemical confinement). (b) Contrast of bonding interactions in adjacent parts of the structure, i.e. separation of metallic and non-metallic domains (structural confinement). (c) Reduced size of metallic particles (size confinement). One playground for the investigation of the properties of matter at the limit of the metallic state is the chemistry of low-valent bismuth compounds, from which metallic nanotubes and nanorods, crystalline metal/salt hybrids, low-dimensional metals and unique clusters emerge. Strange physical effects, like coexistence of ferromagnetism and superconductivity, are found.
Investigation of antihypothalamus and antipituitary antibodies in amateur boxers: is chronic repetitive head trauma-induced pituitary dysfunction associated with autoimmunity?
Authors: Tanriverdi Fatih , De Bellis Annamaria , Battaglia Marina , Bellastella Giuseppe , Bizzarro Antonio , Sinisi Antonio A , Bellastella Antonio , Unluhizarci Kursad , Selcuklu Ahmet , Casanueva Felipe F , Kelestimur Fahrettin
Published: February 2010

Objective

Current data clearly demonstrate that sports-related chronic repetitive head trauma due to boxing might result in hypopituitarism. However, the mechanism of sports-related traumatic brain injury-induced pituitary dysfunction is still unclear. In order to understand whether autoimmune mechanisms could play a role in the pituitary dysfunction due to sports-related head trauma, we investigated the presence of antipituitary antibodies (APAs) and antihypothalamus antibodies (AHAs) in amateur boxers.

Patients and design

Sixty-one actively competing (n=44) or retired (n=17) male boxers (mean age, 26 years; range, 17–53) who had been evaluated regarding pituitary functions previously were included in the study. In all boxers and in 60 age/sex-similar normal controls, AHAs and APAs were investigated by an indirect immunofluorescence method.

Results

AHAs were detected in 13 of 61 boxers (21.3%), and APAs were detected in 14 of 61 boxers (22.9%), but in none of the normal controls. Pituitary dysfunction was significantly higher in AHA-positive boxers (46.2%) than in AHA-negative boxers (10.4%) (P=0.003). There was a significant association between AHA positivity and hypopituitarism due to boxing (odds ratio: 7.37, 95% confidence interval 1.8–30.8). There was no significant association between APA positivity and hypopituitarism.

Conclusions

This study demonstrates for the first time the presence of AHAs and APAs in boxers who were exposed to sports-related head trauma. Moreover, the present investigation provides preliminary evidence that AHAs are associated with the development of pituitary dysfunction in boxers, thus suggesting that autoimmunity may have a role in the pathogenesis.
Suppression of the transcription factor MSX1 gene delays bovine preimplantation embryo development in vitro
Authors: Tesfaye D , Regassa A , Rings F , Ghanem N , Phatsara C , Tholen E , Herwig R , Un C , Schellander K , Hoelker M
Published: February 2010

This study was conducted to investigate the effect of suppressing transcription factor geneMSX1on the development ofin vitroproduced bovine oocytes and embryos, and identify its potential target genes regulated by this gene. Injection of long double-stranded RNA (LdsRNA) and small interfering RNA (siRNA) at germinal vesicle stage oocyte reducedMSX1mRNA expression by 73 and 37% respectively at metaphase II stage compared with non-injected controls. Similarly, injection of the same anti-sense oligomers at zygote stage reducedMSX1mRNA expression by 52 and 33% at 8-cell stage compared with non-injected controls. Protein expression was also reduced in LdsRNA- and siRNA-injected groups compared with non-injected controls at both stages. Blastocysts rates were 33, 28, 20 and 18% in non-injected control, scrambled RNA (scRNA), LdsRNA- and siRNA-injected groups respectively. Cleavage rates were also significantly reduced in Smartpool siRNA (SpsiRNA)-injected group (53.76%) compared with scRNA-injected group (57.76%) and non-injected control group (61%). Large-scale gene expression analysis showed that 135 genes were differentially regulated in SpsiRNA-injected group compared with non-injected controls, of which 54 and 81 were down- and up-regulated respectively due to suppression ofMSX1. Additionally, sequence homology mapping and gene enrichment analysis with known human pathway information identified several functional modules that were affected due to suppression ofMSX1. In conclusion, suppression ofMSX1affects oocyte maturation, embryo cleavage rate and the expression of several genes, suggesting its potential role in the development of bovine preimplantation embryos.
Unified Framework to Evaluate Panmixia and Migration Direction Among Multiple Sampling Locations
Authors: Beerli Peter , Palczewski Michal
Published: February 2010

For many biological investigations, groups of individuals are genetically sampled from several geographic locations. These sampling locations often do not reflect the genetic population structure. We describe a framework using marginal likelihoods to compare and order structured population models, such as testing whether the sampling locations belong to the same randomly mating population or comparing unidirectional and multidirectional gene flow models. In the context of inferences employing Markov chain Monte Carlo methods, the accuracy of the marginal likelihoods depends heavily on the approximation method used to calculate the marginal likelihood. Two methods, modified thermodynamic integration and a stabilized harmonic mean estimator, are compared. With finite Markov chain Monte Carlo run lengths, the harmonic mean estimator may not be consistent. Thermodynamic integration, in contrast, delivers considerably better estimates of the marginal likelihood. The choice of prior distributions does not influence the order and choice of the better models when the marginal likelihood is estimated using thermodynamic integration, whereas with the harmonic mean estimator the influence of the prior is pronounced and the order of the models changes. The approximation of marginal likelihood using thermodynamic integration in MIGRATE allows the evaluation of complex population genetic models, not only of whether sampling locations belong to a single panmictic population, but also of competing complex structured population models.
In Utero Exposure to Smoking and Peripheral Chemoreceptor Function in Preterm Neonates
Authors: Stéphan-Blanchard Erwan , Chardon Karen , Léké André , Delanaud Stéphane , Djeddi Djamal , Libert Jean-Pierre , Bach Véronique , Telliez Frédéric
Published: February 2010

OBJECTIVE:

We aimed to assess the involvement of peripheral chemoreceptor tonic activity in the ventilatory pattern during sleep in preterm neonates exposed in utero to maternal smoking.

PATIENTS AND METHODS:

Peripheral chemoreceptor activity was measured at thermoneutrality in neonates (postmenstrual age: 36.1 ± 1.2 weeks) born to nonsmoking (n = 21) or smoking (n = 16) mothers by performing a 30-second hyperoxic test during active and quiet sleep. Blood oxygen saturation, baseline ventilatory parameters, and central apnea were monitored.

RESULTS:

Prenatal smoking exposure did not modify baseline ventilation. It was interesting to note that prenatal smoking exposure decreased the peripheral chemoreceptor tonic activity during active sleep and increased the response time during quiet sleep. These changes could explain the increase in the time spent in apnea (both with and without blood oxygen desaturation) and in the mean duration of apneic episodes with desaturation found in neonates exposed to smoking in utero. The involvement of a change in the chemoreceptor function is supported by the fact that the peripheral chemoreceptor tonic activity was negatively correlated with the mean duration of apneic episodes with desaturation in the control group only.

CONCLUSIONS:

To our knowledge, this is the first study to reveal that prenatal smoking exposure does not directly modify baseline ventilatory parameters in the neonate but has a negative impact on peripheral chemoreceptor tonic activity. These alterations may increase the risk of sleep respiratory disorders, especially via apnea with desaturation.
Prevention of Choking Among Children
Authors:   Committee on Injury, Violence, and Poison Prevention
Published: February 2010

This Policy Statement was reaffirmed October 2019.

Choking is a leading cause of morbidity and mortality among children, especially those aged 3 years or younger. Food, coins, and toys are the primary causes of choking-related injury and death. Certain characteristics, including shape, size, and consistency, of certain toys and foods increase their potential to cause choking among children. Childhood choking hazards should be addressed through comprehensive and coordinated prevention activities. The US Consumer Product Safety Commission (CPSC) should increase efforts to ensure that toys that are sold in retail store bins, vending machines, or on the Internet have appropriate choking-hazard warnings; work with manufacturers to improve the effectiveness of recalls of products that pose a choking risk to children; and increase efforts to prevent the resale of these recalled products via online auction sites. Current gaps in choking-prevention standards for children's toys should be reevaluated and addressed, as appropriate, via revisions to the standards established under the Child Safety Protection Act, the Consumer Product Safety Improvement Act, or regulation by the CPSC. Prevention of food-related choking among children in the United States has been inadequately addressed at the federal level. The US Food and Drug Administration should establish a systematic, institutionalized process for examining and addressing the hazards of food-related choking. This process should include the establishment of the necessary surveillance, hazard evaluation, enforcement, and public education activities to prevent food-related choking among children. While maintaining its highly cooperative arrangements with the CPSC and the US Department of Agriculture, the Food and Drug Administration should have the authority to address choking-related risks of all food products, including meat products that fall under the jurisdiction of the US Department of Agriculture. The existing National Electronic Injury Surveillance System–All Injury Program of the CPSC should be modified to conduct more-detailed surveillance of choking on food among children. Food manufacturers should design new foods and redesign existing foods to avoid shapes, sizes, textures, and other characteristics that increase choking risk to children, to the extent possible. Pediatricians, dentists, and other infant and child health care providers should provide choking-prevention counseling to parents as an integral part of anticipatory guidance activities.
Premedication for Nonemergency Endotracheal Intubation in the Neonate
Authors: Kumar Praveen , Denson Susan E. , Mancuso Thomas J. ,   Committee on Fetus and Newborn, Section on Anesthesiology and Pain Medicine
Published: February 2010

Endotracheal intubation is a common procedure in newborn care. The purpose of this clinical report is to review currently available evidence on use of premedication for intubation, identify gaps in knowledge, and provide guidance for making decisions about the use of premedication.
Sintomas articulares crônicos em adultos de Pelotas, Rio Grande do Sul, Brasil: prevalência e determinantes
Authors: Silva Vera Regina Lopes da , Menezes Ana Maria Baptista , Noal Ricardo Bica
Published: February 2010

Com o objetivo de estimar a prevalência de sintomas articulares crônicos e seus determinantes, foi realizado um estudo transversal, com 2.953 adultos com 20 anos ou mais, residentes em Pelotas, Rio Grande do Sul, Brasil. Foram investigadas a presença de dor, edema ou rigidez articular, além de informações demográficas, sócio-econômicas e sobre problemas de saúde. A análise multivariável foi realizada pela regressão de Poisson. A prevalência geral de sintomas articulares crônicos foi de 36,5% (42,4% nas mulheres e 28,7% nos homens). A presença da tríade - dor, edema e rigidez articulares - foi de 14,1% e 5,5% nas mulheres e homens, respectivamente. Sintomas articulares crônicos se mostraram linearmente associados ao aumento da idade (RP: 2,9; IC95%: 2,4-3,5), do índice de massa corporal (RP: 1,6; IC95%: 1,3-2,0) e à menor escolaridade (RP: 1,5; IC95%: 1,3-1,8). Somente 6% dos homens e 18% das mulheres relataram diagnóstico médico de artrite. As prevalências gerais de limitações para atividades de vida diária e para atividades laborais, secundárias a sintomas articulares crônicos, foi de 15% e 21%, respectivamente. Os jovens e homens representam a maioria dos indivíduos com sintomas articulares crônicos subdiagnosticados.
Alcohol use and falls among the elderly in Metropolitan São Paulo, Brazil
Authors: Lima Maria Cristina Pereira , Simão Maria Odete , Oliveira Janaina Barbosa de , Cavariani Mariana Braga , Tucci Adriana Marcassa , Kerr-Correa Florence
Published: February 2010

The objectives of this study are to identify the pattern of alcohol use among the elderly and to analyze its association with falls. A population-based survey was conducted in a sample of Metropolitan São Paulo, Brazil, using the GENACIS questionnaire, Gender, Alcohol and Culture: An International Study. Adjusted prevalence ratios were calculated using Poisson Regression with robust variance, and the dependent variable was the occurrence of falls. Interviews were carried out with 432 subjects whose average age was 69.5 years. Regarding alcohol use 50.9% were lifetime abstainers, 25.5% had not drunk in the previous year and 23.6% were current drinkers. Among the latter, 14 (13.7%) were heavy drinkers. In the previous year 24.5% people had falls, which were associated with being a heavy drinker and being older. Although a relationship between being a heavy drinker and falls found in this survey does not allow for inferences on causality, this association supports the hypothesis that alcohol abuse in later life might be related with health problems.
Fatores associados à necessidade subjetiva de tratamento odontológico em idosos brasileiros
Authors: Moreira Rafael da Silveira , Nico Lucélia Silva , Sousa Maria da Luz Rosário de
Published: February 2010

A transição demográfica pela qual o Brasil vem passando nos últimos anos produz como efeito um fenômeno mundialmente conhecido como envelhecimento populacional. Dessa forma, o objetivo deste estudo foi conhecer os fatores relacionados à necessidade de tratamento odontológico percebida por idosos brasileiros. Foi realizado um aprofundamento dos resultados encontrados no levantamento epidemiológico nacional de saúde bucal de 2003. O tamanho total da amostra foi de 5.349 indivíduos. Modelos de regressão de Poisson foram realizadas para identificar as variáveis individuais envolvidas na autopercepção de necessidade de tratamento odontológico. As variáveis associadas à necessidade subjetiva de tratamento odontológico foram diferentes para idosos edêntulos e não edêntulos. Estes achados são importantes para o planejamento da oferta de serviços de saúde bucal para a população, fornecendo uma estimativa sobre os principais problemas que estes indivíduos demandam e quantos necessitariam de atendimento.
Participação da população no controle da dengue: uma análise da sensibilidade dos planos de saúde de municípios do Estado de São Paulo, Brasil
Authors: Ferreira Irma Teresinha Rodrigues Neves , Veras Maria Amélia de Sousa Mascena , Silva Rubens Antonio
Published: February 2010

A participação da população nas ações de combate ao Aedes aegypti tem sido apontada como um dos principais eixos dos programas de controle de dengue. Este estudo objetivou verificar em que medida os planos municipais de saúde contemplam a participação da população nas ações de controle de dengue, em municípios do Estado de São Paulo, Brasil. A análise dos planos de saúde foi realizada com base em um roteiro de leitura abrangendo suas partes constitutivas: (i) a introdução e análise da situação de saúde, (ii) objetivos e metas e (iii) propostas de intervenção. Com base nas menções, foi construído um índice de sensibilidade. Apenas um dos 16 planos de saúde analisados apresentou o índice médio de sensibilidade para a participação da população no controle de dengue, dois apresentaram índice baixo, 12 planos apresentaram índice muito baixo e um apresentou índice nulo de sensibilidade. Tal estudo permitiu identificar que a participação da população não ocupa posição privilegiada na formulação da política municipal de saúde para o controle de dengue.
Photoalignment of nematic liquid crystal on polyamic‐acid‐based soluble polyimide with no side fragments
Authors: Park Seo‐Kyu , Jung Un‐Sung , Kwon Soon‐Bum , Yi Mihye , Ahn Taek , Kim Jeong‐Soo , Kurioz Yuriy , Reznikov Yuriy
Published: February 2010

Abstract— The photoalignment of nematic LC on a layer of newly synthesized UV‐sensitive polyimide without side fragments is reported. The photoaligning polymer advantageously differs from other photoaligning materials because of its extremely low sticking effect and residual DC voltage. These parameters, as well as the UV and thermal stability of the alignment, are not worse than those of rubbed polyimides. At the same time, the new material possesses all the advantages of photoaligning polymers.
Consequences of the cultivation of energy crops for the global nitrogen cycle
Authors: Bouwman A. F. , Grinsven J. J. M. van , Eickhout B.
Published: February 2010

In this paper, we assess the global consequences of implementing first‐ and second‐generation bioenergy in the coming five decades, focusing on the nitrogen cycle. We use a climate mitigation scenario from the Organization for Economic Cooperation and Development's (OECD) Environmental Outlook, in which a carbon tax is introduced to stimulate production of biofuels from energy crops. In this scenario, the area of energy crops will increase from 8 Mha in the year 2000 to 270 Mha (14% of total cropland) and producing 5.6 Pg dry matter per year (12% of energy use) in 2050. This production requires an additional annual 19 Tg of N fertilizer in 2050 (15% of total), and this causes a global emission of 0.7 Tg of N2O‐N (8% of agricultural emissions), 0.2 Tg NO‐N (6%), and 2.2 Tg of NH3‐N (5%). In addition, we project that 2.6 Tg of NO3−‐N will leach from fields under energy crops. The emissions of N2O may be an important term in the greenhouse gas balance of biofuels produced from energy crops.
Testing alternative models of climate‐mediated extirpations
Authors: Beever Erik A. , Ray Chris , Mote Philip W. , Wilkening Jennifer L.
Published: February 2010

Biotic responses to climate change will vary among taxa and across latitudes, elevational gradients, and degrees of insularity. However, due to factors such as phenotypic plasticity, ecotypic variation, and evolved tolerance to thermal stress, it remains poorly understood whether losses should be greatest in populations experiencing the greatest climatic change or living in places where the prevailing climate is closest to the edge of the species' bioclimatic envelope (e.g., at the hottest, driest sites). Research on American pikas (Ochotona princeps) in montane areas of the Great Basin during 1994–1999 suggested that 20th‐century population extirpations were predicted by a combination of biogeographic, anthropogenic, and especially climatic factors. Surveys during 2005–2007 documented additional extirpations and within‐site shifts of pika distributions at remaining sites. To evaluate the evidence in support of alternative hypotheses involving effects of thermal stress on pikas, we placed temperature sensors at 156 locations within pika habitats in the vicinity of 25 sites with historical records of pikas in the Basin. We related these time series of sensor data to data on ambient temperature from weather stations within the Historical Climate Network. We then used these highly correlated relationships, combined with long‐term data from the same weather stations, to hindcast temperatures within pika habitats from 1945 through 2006. To explain patterns of loss, we posited three alternative classes of direct thermal stress: (1) acute cold stress (number of days below a threshold temperature); (2) acute heat stress (number of days above a threshold temperature); and (3) chronic heat stress (average summer temperature). Climate change was defined as change in our thermal metrics between two 31‐yr periods: 1945–1975 and 1976–2006. We found that patterns of persistence were well predicted by metrics of climate. Our best models suggest some effects of climate change; however, recent and long‐term metrics of chronic heat stress and acute cold stress, neither previously recognized as sources of stress for pikas, were some of the best predictors of pika persistence. Results illustrate that extremely rapid distributional shifts can be explained by climatic influences and have implications for conservation topics such as reintroductions and early‐warning indicators.
Global assessment of nitrogen deposition effects on terrestrial plant diversity: a synthesis
Authors: Bobbink R. , Hicks K. , Galloway J. , Spranger T. , Alkemade R. , Ashmore M. , Bustamante M. , Cinderby S. , Davidson E. , Dentener F. , Emmett B. , Erisman J-W. , Fenn M. , Gilliam F. , Nordin A. , Pardo L. , De Vries W.
Published: February 2010

Atmospheric nitrogen (N) deposition is a recognized threat to plant diversity in temperate and northern parts of Europe and North America. This paper assesses evidence from field experiments for N deposition effects and thresholds for terrestrial plant diversity protection across a latitudinal range of main categories of ecosystems, from arctic and boreal systems to tropical forests. Current thinking on the mechanisms of N deposition effects on plant diversity, the global distribution of G200 ecoregions, and current and future (2030) estimates of atmospheric N‐deposition rates are then used to identify the risks to plant diversity in all major ecosystem types now and in the future.

This synthesis paper clearly shows that N accumulation is the main driver of changes to species composition across the whole range of different ecosystem types by driving the competitive interactions that lead to composition change and/or making conditions unfavorable for some species. Other effects such as direct toxicity of nitrogen gases and aerosols, long‐term negative effects of increased ammonium and ammonia availability, soil‐mediated effects of acidification, and secondary stress and disturbance are more ecosystem‐ and site‐specific and often play a supporting role. N deposition effects in mediterranean ecosystems have now been identified, leading to a first estimate of an effect threshold. Importantly, ecosystems thought of as not N limited, such as tropical and subtropical systems, may be more vulnerable in the regeneration phase, in situations where heterogeneity in N availability is reduced by atmospheric N deposition, on sandy soils, or in montane areas.

Critical loads are effect thresholds for N deposition, and the critical load concept has helped European governments make progress toward reducing N loads on sensitive ecosystems. More needs to be done in Europe and North America, especially for the more sensitive ecosystem types, including several ecosystems of high conservation importance.

The results of this assessment show that the vulnerable regions outside Europe and North America which have not received enough attention are ecoregions in eastern and southern Asia (China, India), an important part of the mediterranean ecoregion (California, southern Europe), and in the coming decades several subtropical and tropical parts of Latin America and Africa. Reductions in plant diversity by increased atmospheric N deposition may be more widespread than first thought, and more targeted studies are required in low background areas, especially in the G200 ecoregions.
Annular Velocity Enhancement with Gas Lift as a Deliquification Method for Tight Gas Wells with Long Completion Intervals
Authors: Pohler Steven A. , Holmes William D. , Cox Stuart A.
Published: February 2010

It is common practice in the industry to complete multiple reservoirs in a single wellbore in order to establish commercial production rates from tight gas completions. In some cases these zones are separated vertically by several hundred to over a thousand feet. The deliquification of these completions is one of the most challenging problems facing our industry. Many of the deliquification methods currently being utilized are effective over only a portion of the wellbore. In many cases these methods do not allow for removal of liquid across the entire completed interval. If the liquid is not effectively removed from the well, the near wellbore region will become saturated with fluid and reduce the well's productivity. This paper will propose a new completion strategy which has been incorporated into the completion of tight gas wells to address the problems associated with deliquification of long completion intervals. Laboratory experiments and field data will be presented to quantify the effects of inadequate liquid removal. A case study will also be presented to demonstrate the successful application of this alternate completion strategy. This completion strategy applies to unconventional gas wells, vertical and horizontal gas wells.
Evolution of Mesaverde Stimulations in the Piceance Basin: A Case History of the Application of Lean Six Sigma Tools
Authors: Juranek Thomas A. , Seeburger David , Tolman Randy , Choi Nancy H. , Pirog Theodore W. , Jorgensen Dan , Jorgensen Erik
Published: February 2010

Unconventional Gas reservoirs continue to be a fast growing sector within the petroleum industry. These reservoirs include Coal Bed Methane, Shale Gas, and Tight Gas Sands. ExxonMobil has been actively developing Tight Gas reservoirs for over 10 years in the Mesaverde formation in the Piceance Basin in Northwest Colorado. This case study chronicles the evolution of hydraulic fracture stimulations during this time period as experienced by ExxonMobil. Aspects addressed include stimulation design evolution and the application of Lean Six Sigma tools to optimize stimulation designs in a highly variable environment.
Kerogen Density in the Marcellus Shale
Authors: Ward J. A.
Published: February 2010

As interest in the Marcellus shale began to increase early regional characteristics of the shale were derived from existing borehole log data supplemented by sparse core and laboratory data. Some of the earliest work on Devonian shales based on gamma and density logs had a goal of predicting the volume of low density high gamma ray organic material (kerogen) as a guide to understanding the deposition of the shales. Subsequently, work focused on not only calculating the density of upper Devonian shales, but applying a correction to the density and neutron logs to correct them for the effect of organic material. Once corrected the logs are suitable for porosity calculation. Analysis of upper Devonian core data for the derivation of kerogen density indicated that there is a relationship between thermal maturity and the density of organic material.

Review of key wells from regional work focused on three wells in West Virginia for which a modern log suite is available and geochemical work is present. The three wells have thermal maturity that range fro Ro of 1.5 to 2.68. Log analyses from these wells suggest that the density of the kerogen ranges from 1.53 to 1.79 gr/cc. Current practice in log analysis and core analysis often assumes that kerogen density is fixed near 1.1 gr/cc. Log and core analysis in the Marcellus shale should be completed with the concept that the density of the kerogen is not fixed, but varies as a function of thermal maturity.
Micro-Structural Studies of Gas Shales
Authors: Sondergeld C. H. , Ambrose R. J. , Rai C. S. , Moncrieff J.
Published: February 2010

To understand the deliverability of gas shales, one needs to understand the controls on porosity and permeability. The microstructure of shale is defined in part by the grain size which is typically less than 5 μm and composition. Gas shales unlike other lithologies contain significant quantities of organic matter in various stages of maturation. The geometry and nature of the mineralogical components and the organics would be easy to describe if the objects could be identified optically. Most investigations into shale microstructure have relied on technologies such as Scanning Electron Microscopy (SEM), X-ray imaging, Transmission Electron Microscopy (TEM) or Scanning Acoustic Microscopy (SAM). Each has advantages an limitations. Our focus here is limited to SEM studies we performed on gas shales. Our journey began with generic imaging of broken surfaces and has progress to imaging of ion-milled surfaces in dual beam SEM. The latest technology has provide three dimension images with maximum resolution of 4-5nm pores. Porosity is found on the microscale in organics, between grains, in pyrite framboids, fossils, within minerals and in the form of microcracks. The majority of pores in some shales an located in the organics. Other shales show the porosity to be largely associated with minerals. SEM resolved pore dimension agree well with "as received" NMR measurement. However, high pressure mercury injection measurements suggest that the paths connecting these pores are even smaller. Three dimensional reconstruction of sequentially ion-milled surfaces using a dual beam SEM provides controls on the volumetric distribution of pores and organics and their connectivity. Initial and limited analyses indicate that the shales investigated are dominated by smaller pores. Keep in mind that any such study only samples an extremely small portion of any reservoir and that while generalizations are tempting, statistical studies are required to establish the universality of such observations.
Microseismic Monitoring: Technology State of Play
Authors: Duncan Peter M.
Published: February 2010

Microseismic monitoring has been largely accepted as an important adjunct to the hydraulic fracturing of unconventional gas reservoirs. Both surface and downhole methodologies are now common for the performance of such monitoring, each with its advantages and challenges. This paper discusses the state of the technology today and where current work is being directed at reducing cost and enhancing the value of microseismic monitoring.
Unconventional Geophysics for Unconventional Plays
Authors: Rich J. P. , Ammerman M.
Published: February 2010

In conventional plays the role of the geophysicist is primarily that of locating and delineating the resource. This is most commonly accomplished through the use of active source seismic exploration. In this classic case it is the responsibility of the geophysicist to identify the structures associated with the trap and migration pathways of the resource. In the last twenty years this role has been expanded through the applicability of direct hydrocarbon indicators where, particularly in the Gulf of Mexico, the resource itself can often be identified using seismic exploration. In the case of unconventional resources neither the trap nor the presence of hydrocarbons are unknowns. The source rock, reservoir and trap are continuous and well defined. As such it would be easy to dismiss the geophysicist's role as diminished to one where his primary responsibilities are secondary concerns, such as hazard avoidance through the location of faults. However, in practice, the role of the unconventional geophysicist is much more complex and multi-dimensional. Access to resource in an unconventional rock is largely controlled by exposure to the rock, i.e. how efficiently it can be hydraulically fractured. The unconventional geophysicist can contribute to the understanding of how to best access the resource by studying the finer scale heterogeneities in the rock which are manifested indirectly through various seismic attributes such as anisotropy and curvature, and directly measured through microseismic monitoring of hydraulic stimulations.
Analysis of Production Data from Fractured Shale Gas Wells
Authors: Anderson D. M. , Nobakht M. , Moghadam S. , Mattar L.
Published: February 2010

Long-term shale gas well performance characteristics are generally not well understood. The ultra-low permeability of shale ensures the continuing presence of pressure transient effects during well production. This makes production forecasting a difficult and non-unique exercise. Conventional methods have proven to be too pessimistic, in many cases, because they assume a depletion-dominated system. Recently, more suitable forecasting methods have been developed that account for long-term transient effects. These methods incorporate a transient model (usually linear flow) which transitions into a conventional boundary-dominated flow model after a prescribed time or upon achieving a certain region of investigation. The underlying concept assumes that once a transition to boundary-dominated flow is observed, depletion will dominate the production going forward. Although this methodology has been successfully applied for a variety of tight gas reservoirs, it may not be the right model for fractured shale gas (and some conventional tight gas) reservoirs. Fractured shale gas reservoirs get their productivity from the stimulated reservoir volume (SRV), which may be quite limited in areal extent but is surrounded by a low-permeability reservoir (matrix). Thus, the mechanism for long-term production includes a late-time transition from depletion of the SRV, back to infinite acting (linear or pseudo-radial) flow. This "return" to infinite acting flow may or may not provide contribution to recoverable reserves within a practical time-frame, but it should be considered nonetheless.

In this paper we present a straight forward methodology for determining the major well performance characteristics of fractured horizontal shale gas wells, considering the impact of uncertainty and non-uniqueness. The focus will be on determining the dominant flow regimes and bulk properties from the data, and then defining a suitable, simple reservoir model for production forecasting, using practical experience and all available information. Field examples from the Barnett, Marcellus, and Haynesville shales are included.
Coalbed Methane: Current Evaluation Methods, Future Technical Challenges
Authors: Clarkson C. R. , Bustin R. M.
Published: February 2010

Coalbed methane (CBM) produced from subsurface coal deposits, has been produced commercially now for over 30 years in North America, and relatively recently in Australia, China and India. Historical challenges to predicting CBM well performance and long-term production have included: accurate estimation of gas-in-place (including quantification of in-situ adsorbed gas storage); estimation of initial fluid saturations (in saturated reservoirs) and mobile-water-in-place, estimation of the degree of under-saturation (undersaturated coals produce mainly water above desorption pressure); estimation of initial absolute permeability (system); selection of appropriate relative permeability curves; estimation of absolute permeability changes as a function of depletion; prediction of produced gas composition changes as a function of depletion; accounting for multi-layer behavior, and accurate prediction of cavity or hydraulic fracture properties. These challenges have primarily been a result of the unique reservoir properties of CBM. Much progress has been made in the past decade to evaluate fundamental properties of coal reservoirs, but there is still work to be done to obtain accurate estimates of some basic reservoir properties.

In recent years, horizontal wells and more complex well architectures and stimulation methodologies have been implemented to improve recovery of CBM. These more complex development options bring with them a new set of challenges for operators producing CBM. The exploitation of more geologically-complex coal with poorer reservoir quality will necessitate new and inventive ways to develop the existing natural gas resources and possibly combine this with new methods to extract energy from the coal in-situ. Development planning in these scenarios will become increasingly complex as will evaluation methods.

The purpose of the current work is to review the state-of-the-art in CBM reservoir property and stimulation efficiency evaluation and speculate on possible CBM development scenarios for the future and the technical challenges they will bring. Current and future work required to meet these challenges will be discussed in the hope that industry, academia, and government bodies alike will be proactive in the development of solutions that will make future CBM recovery efficient, economic, and environmentally friendly.
Phytoavailability of Cadmium in Long‐Term Biosolids‐Amended Soils
Authors: Kukier Urszula , Chaney Rufus L. , Ryan James A. , Daniels W. Lee , Dowdy Robert H. , Granato Thomas C.
Published: February 2010

Agronomic use of biosolids has raised concern that plant availability of biosolids‐Cd will increase with time after cessation of biosolids application. It has been demonstrated that chemical extractability of Cd is persistently decreased in biosolids‐amended soils. This study was conducted to determine if Cd phytoavailability in long‐term biosolids‐amended soils was also persistently decreased. Paired control and biosolids‐amended soils were collected from three experimental sites where large cumulative rates of biosolids were applied about 20 yr ago. The pH of all soils [in 0.01 mol L−1 Ca(NO3)2] was adjusted to 6.5 ± 0.2. Increasing rates of Cd‐nitrate (from 0 to 10.0 mg Cd kg−1 soil) enriched in 111Cd stable isotope were added to all soils, and Romaine lettuce (Lactuca sativa L. var. longifolia Lam.) was grown in pots to bioassay phytoavailable Cd. After harvest, Cd concentrations in shoots and labile pool of Cd (CdL) in soils were determined. The relationship between added salt‐Cd and Cd concentrations in lettuce shoots was linear for all soils tested. Ratios of (shoot Cd):(soil Cd) slopes were highest in the control soils. Biosolids amendment decreased (shoot Cd):(soil Cd) slopes to varied extent depending on biosolids source, properties, and application rate. The decrease in slope in comparison to the control was an indication of the lower phytoavailability of Cd in biosolids‐amended soils. A significant negative correlation existed between Cd uptake slopes and soil organic matter, free and amorphous Fe and Al oxides, Bray‐P, and soil and plant Zn. Biosolids‐Cd was highly labile (%L 80–95) except for Fulton County soil (%L = 61).
Combining Size Fractionation, Scanning Electron Microscopy, and X‐ray Absorption Spectroscopy to Probe Zinc Speciation in Pig Slurry
Authors: Legros S. , Doelsch E. , Masion A. , Rose J. , Borschneck D. , Proux O. , Hazemann J‐L. , Saint‐Macary H. , Bottero J‐Y.
Published: February 2010

Zinc occurs in high quantity in pig slurry since it is used as an essential micronutrient at high concentrations in animal feeds despite the low Zn assimilation by pigs. Zinc accumulation was measured in soil surface layers that had been amended with pig slurry, while also determining the phytotoxicity as well as the extent of groundwater quality degradation. To accurately predict the mobility and bioavailability of Zn derived from pig slurry spreading, the speciation of this element has to be assessed since the total concentration is not sufficient. This study involved a combination of techniques to investigate Zn speciation in pig slurry. Size fractionation was first performed to account for the complexity of pig slurry, and 75% of total Zn was detected in the 0.45‐ to 20‐μm particle‐size range. Then X‐ray diffraction, scanning electron microscopy, coupled with energy dispersive spectrometer, and extended X‐ray absorption fine structure analyses were combined to assess Zn speciation. The findings highlighted the presence of 49% Zn bound to organic matter, 37% amorphous Zn hydroxides [Zn(OH)2], and 14% sphalerite (ZnS).