bluuebunny/crossref_metadata_2025 huggingface dataset:
Lessons From Evaluations of Purchaser Pay-for-Performance Programs
Authors: Christianson Jon B. , Leatherman Sheila , Sutherland Kim
Published: November 2008

There has been a growing interest in the use of financial incentives to encourage improvements in the quality of health care. Several articles have reviewed past studies of the impact of specific incentive arrangements, but these studies addressed small-scale experiments, making their findings arguably of limited relevance to current improvement efforts. In this article, the authors review evaluations of more recent pay-for-performance initiatives instituted by health plans or by provider organizations in cooperation with health plans. Findings show improvement in selected quality measures in most of these initiatives, but the contribution of financial incentives to that improvement is not clear; the incentives typically were implemented in conjunction with other quality improvement efforts, or there was not a convincing comparison group. However, the literature relating to purchaser pay-for-performance initiatives does underscore several important issues that deserve attention going forward that relate to the design and implementation of pay-for-performance initiatives.
Keratinocyte growth factor enhances DNA plasmid tumor vaccine responses after murine allogeneic bone marrow transplantation
Authors: Jenq Robert R. , King Christopher G. , Volk Christine , Suh David , Smith Odette M. , Rao Uttam K. , Yim Nury L. , Holland Amanda M. , Lu Sydney X. , Zakrzewski Johannes L. , Goldberg Gabrielle L. , Diab Adi , Alpdogan Onder , Penack Olaf , Na Il-Kang , Kappel Lucy W. , Wolchok Jedd D. , Houghton Alan N. , Perales Miguel-Angel , van den Brink Marcel R. M.
Published: November 2008

Keratinocyte growth factor (KGF), which is given exogenously to allogeneic bone marrow transplantation (allo-BMT) recipients, supports thymic epithelial cells and increases thymic output of naive T cells. Here, we demonstrate that this improved T-cell reconstitution leads to enhanced responses to DNA plasmid tumor vaccination. Tumor-bearing mice treated with KGF and DNA vaccination have improved long-term survival and decreased tumor burden after allo-BMT. When assayed before vaccination, KGF-treated allo-BMT recipients have increased numbers of peripheral T cells, including CD8+ T cells with vaccine-recognition potential. In response to vaccination, KGF-treated allo-BMT recipients, compared with control subjects, generate increased numbers of tumor-specific CD8+ cells, as well as increased numbers of CD8+ cells producing interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α). We also found unanticipated benefits to antitumor immunity with the administration of KGF. KGF-treated allo-BMT recipients have an improved ratio of T effector cells to regulatory T cells, a larger fraction of effector cells that display a central memory phenotype, and effector cells that are derived from a broader T-cell–receptor repertoire. In conclusion, our data suggest that KGF can function as a potent vaccine adjuvant after allo-BMT through its effects on posttransplantation T-cell reconstitution.
SCL and associated proteins distinguish active from repressive GATA transcription factor complexes
Authors: Tripic Tamara , Deng Wulan , Cheng Yong , Zhang Ying , Vakoc Christopher R. , Gregory Gregory D. , Hardison Ross C. , Blobel Gerd A.
Published: November 2008

GATA-1 controls hematopoietic development by activating and repressing gene transcription, yet the in vivo mechanisms that specify these opposite activities are unknown. By examining the composition of GATA-1–associated protein complexes in a conditional erythroid rescue system as well as through the use of tiling arrays we detected the SCL/TAL1, LMO2, Ldb1, E2A complex at all positively acting GATA-1–bound elements examined. Similarly, the SCL complex is present at all activating GATA elements in megakaryocytes and mast cells. In striking contrast, at sites where GATA-1 functions as a repressor, the SCL complex is depleted. A DNA-binding defective form of SCL maintains association with a subset of active GATA elements indicating that GATA-1 is a key determinant for SCL recruitment. Knockdown of LMO2 selectively impairs activation but not repression by GATA-1. ETO-2, an SCL-associated protein with the potential for transcription repression, is also absent from GATA-1–repressed genes but, unlike SCL, fails to accumulate at GATA-1–activated genes. Together, these studies identify the SCL complex as a critical and consistent determinant of positive GATA-1 activity in multiple GATA-1–regulated hematopoietic cell lineages.
Amifostine reduces lung vascular permeabilityviasuppression of inflammatory signalling
Authors: Fu P. , Birukova A. A. , Xing J. , Sammani S. , Murley J. S. , Garcia J. G. N. , Grdina D. J. , Birukov K. G.
Published: November 2008

Despite an encouraging outcome of antioxidant therapy in animal models of acute lung injury, effective antioxidant agents for clinical application remain to be developed. The present study investigated the effect of pre-treatment with amifostine, a thiol antioxidant compound, on lung endothelial barrier dysfunction induced by Gram-negative bacteria wall-lipopolysaccharide (LPS).

Endothelial permeability was monitored by changes in transendothelial electrical resistance. Cytoskeletal remodelling and reactive oxygen species (ROS) production was examined by immunofluorescence. Cell signalling was assessed by Western blot. Measurements of Evans blue extravasation, cell count and protein content in bronchoalveolar lavage fluid were used asin vivoparameters of lung vascular permeability.

Hydrogen peroxide, LPS and interleukin-6 caused cytoskeletal reorganisation and increased permeability in the pulmonary endothelial cells, reflecting endothelial barrier dysfunction. These disruptive effects were inhibited by pre-treatment with amifostine and linked to the amifostine-mediated abrogation of ROS production and redox-sensitive signalling cascades, including p38, extracellular signal regulated kinase 1/2, mitogen-activated protein kinases and the nuclear factor-κB pathway.In vivo, concurrent amifostine administration inhibited LPS-induced oxidative stress and p38 mitogen-activated protein kinase activation, which was associated with reduced vascular leak and neutrophil recruitment to the lungs.

The present study demonstrates, for the first time, protective effects of amifostine against lipopolysaccharide-induced lung vascular leakin vitroand in animal models of lipopolysaccharide-induced acute lung injury.
Pre-ischaemic exogenous surfactant reduces pulmonary injury in rat ischaemia/reperfusion
Authors: Mühlfeld C. , Schaefer I-M. , Becker L. , Bussinger C. , Vollroth M. , Bosch A. , Nagib R. , Madershahian N. , Richter J. , Wahlers T. , Wittwer T. , Ochs M.
Published: November 2008

The optimal timing of exogenous surfactant application to reduce pulmonary injury and dysfunction was investigated in a rat lung ischaemia and reperfusion injury model.

Lungs were subjected to flush perfusion, surfactant instillation, cold ischaemia (4°C, 4 h) and reperfusion (60 min). Animals received surfactant before (group 1) or at the end (2) of ischaemia, or during reperfusion (3) or not at all (4). Control groups included “worst case” without Perfadex and surfactant (5), “no injury” without (6) or with surfactant (7), and ischaemia with pre-ischaemic surfactant (8). Intra-alveolar oedema and blood–air barrier injury were estimated by light and electron microscopic stereology. Perfusate oxygenation and pulmonary arterial pressure (Ppa) were determined during reperfusion in groups 1 to 4.

Intra-alveolar oedema was almost absent in groups 1, 6, 7 and 8, pronounced in 2, 3 and 4, and severe in 5. Blood–air barrier injury was moderate in groups 1 and 8, slightly pronounced in 2, 3 and 4, extensive in 5 and almost absent in 6 and 7. Perfusate oxygenation was significantly higher in group 1 compared with groups 2 to 4.Ppadid not differ between the groups.

In conclusion, exogenous surfactant attenuates intra-alveolar oedema formation and blood–air barrier damage and improves perfusate oxygenation in the rat lung, especially when applied before ischaemic storage.
High-sensitive C-reactive protein is associated with reduced lung function in young adults
Authors: Rasmussen F. , Mikkelsen D. , Hancox R. J. , Lambrechtsen J. , Nybo M. , Hansen H. S. , Siersted H. C.
Published: November 2008

Systemic inflammation has been associated with reduced lung function. However, data on the interrelationships between lung function and inflammation are sparse, and it is not clear if low-grade inflammation leads to reduced lung function.

Associations between high-sensitive C-reactive protein (CRP) and spirometric lung function were assessed in a population-based cohort of ∼1,000 Danes aged 20 yrs.

In males, the average decline in forced expiratory volume in one second (FEV1) in the highest CRP quintile was 23 mL·yr−1versus1.6 mL·yr−1in the lowest quintile. In females, the average decline was 6.2 mL·yr−1in the highest CRP quintileversusan increase of 1.8 mL·yr−1in the lowest CRP quintile. In a multiple regression analysis adjusted for sex, body mass index, cardiorespiratory fitness, smoking, asthma, airway hyperresponsiveness and serum eosinophil cationic protein, higher levels of CRP at age 20 yrs were associated with a greater reduction in both FEV1and forced vital capacity between ages 20 and 29 yrs.

The findings show that higher levels of C-reactive protein in young adults are associated with subsequent decline in lung function, suggesting that low-grade systemic inflammation in young adulthood may lead to impaired lung function independently of the effects of smoking, obesity, cardiorespiratory fitness, asthma and eosinophilic inflammation.
Acquisition and eradication ofP. aeruginosain young children with cystic fibrosis
Authors: Douglas T. A. , Brennan S. , Gard S. , Berry L. , Gangell C. , Stick S. M. , Clements B. S. , Sly P. D.
Published: November 2008

When do infants and young children with cystic fibrosis acquire infection withPseudomonas aeruginosa? Can this be eradicated when first detected?

Children <6 yrs of age participated in an annual bronchoalveolar lavage (BAL)-based microbiological surveillance programme in Perth, Australia. WhenP. aeruginosawas detected, an eradication programme using combination treatment withi.v., oral and nebulised antibiotics was undertaken. Repeat BAL was performed 3 months following treatment, to assess eradication success.

P. aeruginosawas detected in 33 (28.4%) children; median (range) age at detection was 30.5 (3.3–71.4) months.P. aeruginosawas mucoid at detection in six (18.2%) out of 33 patients and associated with respiratory symptoms in 16 (48.5%) out of 33 children. In total, 26 children underwent eradication therapy, withP. aeruginosaeradicated in 20 (77%) out of 26 following one eradication cycle and in three (total 88%) additional children following a second cycle. Eradication was associated with a significant decrease in neutrophil elastase and interleukin-1β in BAL fluid 12 months post eradication.

Eradication ofPseudomonas aeruginosainfection is achievable in young children with cystic fibrosis for up to 5 yrs using combinationi.v., oral and nebulised antibiotic therapy and is associated with reduced pulmonary inflammation 12 months post eradication.
Progression of snoring and obstructive sleep apnoea: the role of increasing weight and time
Authors: Berger G. , Berger R. , Oksenberg A.
Published: November 2008

The aim of the present study was to examine the natural evolution of primary snoring and obstructive sleep apnoea (OSA) in adult male patients.

Retrospective analysis was performed on 160 untreated patients with primary snoring and mild, moderate and severe OSA who had two polysomnographic recordings. The mean time between recordings (TBR) was 5.1±3 yrs.

The mean apnoea/hypopnoea index (AHI), body mass index (BMI), and lowest arterial oxygen saturation level during rapid eye movement (REM) and non-REM sleep showed a significant worsening effect. The change in AHI differed among the groups showing a similar significant increase in AHI for primary snoring, mild and moderate OSA and an insignificant decrease for severe OSA patients. Stepwise linear regression showed that only ΔBMI and time were significant predictors for AHI change. A model for the mean AHI change showed that ΔAHI  =  (4.33×ΔBMI) + (0.66×TBR). After adjusting for confounders, multiple regression analysis indicated that age and high BMI, but not AHI, were significant risk factors for developing hypertension and/or cardiovascular disease.

Patients with primary snoring and mild and moderate obstructive sleep apnoea had a similar increase in the apnoea/hypopnoea index over time, which depended mainly on weight gain and, to a lesser extent, on time.
Evolution of microRNA expression during human bronchial squamous carcinogenesis
Authors: Mascaux C. , Laes J. F. , Anthoine G. , Haller A. , Ninane V. , Burny A. , Sculier J. P.
Published: November 2008

MicroRNAs, negative post-transcriptional regulators of gene expression, are involved in cancer.

Their role in early bronchial carcinogenesis was analysed in 60 biopsies obtained by fluorescence bronchoscopy (six per stage: normal tissue of nonsmokers, normal normofluorescent and hypofluorescent bronchial tissue of smokers, hyperplasia, metaplasia, mild, moderate and severe dysplasia,in situcarcinoma and invasive squamous cell carcinoma (SQCC)).

In total, 69 microRNAs were found to be differentially expressed in the course of bronchial carcinogenesis. Among them, some microRNAs showed a linear evolution of their expression level, such as miR-32 and miR-34c, whose expression progressively decreased from normal bronchial tissues of nonsmokers to SQCC. Others behaved differently at successive stages, such as miR-142-3p or miR-9, or are only altered from a specific stage, such as miR-199a or miR-139. MicroRNAs globally followed a two-step evolution, first decreasing (a reverse of their increase during embryogenesis) during the earliest morphological modifications of bronchial epithelium, and thereafter increasing at later stages of lung carcinogenesis. Moreover, microRNA expression was very efficient for the prediction of the histological classification between low- and high-grade lesions and betweenin situand invasive carcinoma.

The present data show, for the first time, that microRNAs are involved in bronchial carcinogenesis from the very early steps of this process and, thus, could provide tools for early detection of lung cancer.
Lipopolysaccharide-binding protein and CD14 are increased in the bronchoalveolar lavage fluid of smokers
Authors: Regueiro V. , Campos M. A. , Morey P. , Sauleda J. , Agustí A.G.N. , Garmendia J. , Bengoechea J. A.
Published: November 2008

Lipopolysaccharide-binding protein (LBP) and CD14 contribute to the recognition of pathogens by cells, which triggers the activation of defence responses. Smoking is a risk factor for the development of chronic obstructive pulmonary disease (COPD) and respiratory infections. The current authors theorised that levels of LBP and CD14 in the lungs of smokers would be higher than those in the lungs of never-smokers. These elevated levels could affect host responses upon infection.

LBP, soluble CD14 (sCD14) and interleukin (IL)-8 were detected by ELISA. Nuclear factor (NF)-κB, p38 and the inhibitor IκBα were studied by immunoassays. Gene expression was assessed by RT-PCR.

Bronchoalveolar lavage levels of LBP and CD14 were significantly higher in smokers and COPD patients than in never-smokers, whereas levels of both proteins were not significantly different between smokers and COPD patients. IL-6, IL-1β and cigarette smoke condensate induced the expression of LBP and CD14 by airway epithelial cells. LBP and sCD14 inhibited the nontypeableHaemophilus influenzae(NTHi)-dependent secretion of IL-8 and the activation of NF-κB and p38 mitogen-activated protein kinase signalling pathways but they increased the internalisation of NTHi by airway epithelial cells.

Thus, in the inflamed airways of smokers both proteins could contribute to inhibit bacteria-dependent cellular activation without compromising the internalisation of pathogens by airway cells.
Clinical signs and symptoms of oropharyngeal aspiration and dysphagia in children
Authors: Weir K. , McMahon S. , Barry L. , Masters I. B. , Chang A. B.
Published: November 2008

The diagnostic value of various signs and symptoms (clinical markers) in predicting oropharyngeal aspiration (OPA) or swallowing dysfunction has not been established in children. The present retrospective study was undertaken to: 1) identify specific clinical markers associated with radiographic evidence of OPA, isolated laryngeal penetration (ILP) and post-swallow residue (PSR); 2) determine the sensitivity and specificity of clinical markers associated with OPA; and 3) determine the influence of age and neurological impairment on clinical markers of OPA.

In total, 11 clinical markers of dysphagia were compared with the videofluoroscopic swallow study (VFSS) results (OPA, ILP and PSR) in 150 children on diets of thin fluid and purée consistencies. Chi-squared and logistic regression were used to analyse the association between clinical markers and VFSS-identified swallowing dysfunction.

In children with OPA, wet voice (odds ratio (OR) 8.90, 95% confidence interval (CI) 2.87–27.62), wet breathing (OR 3.35, 95% CI 1.09–10.28) and cough (OR 3.30, 95% CI 1.17–9.27) were significantly associated with thin fluid OPA. Predictive values included: wet voice (sensitivity 0.67; specificity 0.92); wet breathing (sensitivity 0.33; specificity 0.83); and cough (sensitivity 0.67; specificity 0.53). No clinical markers were significantly associated with OPA, ILP or PSR on the purée consistency. Cough was significantly associated with PSR on thin fluids (OR 3.59, 95% CI 1.22–10.55). Differences were found for age.

Wet voice, wet breathing and cough were good clinical markers for children with oropharyngeal aspiration on thin fluid but not on purée. Age and neurological status influenced the significance of these clinical markers.
“The Best of Me Is There”: Emerson as Lecturer and Celebrity
Authors: Carr O'Neill Bonnie
Published: November 2008

By definition, celebrities exist in public as an association of physical traits or projected values. Celebrity was problematic for Emerson in three areas. First, celebrity heightened Emerson's anxieties about his friendships and intimate relationships. Emerson's relative comfort in the public arena of the lecture hall, as compared with the private arena of intimate relationships, carries mixed results when attention to his body rather than his ideas becomes the focus of his success. Second, celebrity accentuates the tension between interest in public persons and the social conformity that Emerson consistently urges his readers to shun. Third, celebrity's attention to the physical person leads to misinterpretations of Emerson's lectures. From the first generation of Emerson's biographers forward, critics have disparaged contemporary audiences as insensitive to the complexities of his lectures. This essay, however, considers the possible uses of the celebrity for the culture that both created and mistook him. Viewed in the light of Emerson's celebrity, misinterpretation of his lectures reveals his audiences' appreciation for intellectual accomplishment and their desire for the spiritual uplift brought by physical proximity to “genius.” In addition, because Emerson's celebrity encouraged a range of interpretations of his cultural relevance, it required individuals to examine Emerson's reputation for themselves, and it thereby fostered the kind of self-reliant thinking that Emerson himself advocated. Emerson's case reveals that, in an age of mass culture, the ability to interpret celebrities' significance is a key to critical thinking and a valuable form of literacy.
Simulation of truncated ideal contour nozzle separation considering external stream interactions
Authors: Moshfegh A , Ebrahimi R , Shams M
Published: November 2008

The multi-block computational approach is used to study the physics of shock and turbulent flow separation in the truncated ideal contour nozzle, considering the jet and external stream interactions. The code employs a fully implicit finite volume, lower—upper symmetric successive overreaction scheme with van Leer flux vector splitting using monotone upstream-centred schemes for conservation law technique to get a higher-order spatial accuracy for the total variation diminishing property. Several combustion-chamber-to-ambient pressure ratios at surrounding Mach range from 0.5 to 1.2 for both cold and hot gases are investigated to study their effects on the wall pressure, the separation point, and the thrust force. It is observed that although the flight Mach number and ambient pressure decrements delay the separation and raise the specific impulse, the combustion chamber temperature has a reverse effect on the separation point. Crisscrossing (or diamond-shaped) shock waves in the supersonic exit jet enforce the compressible flow properties to oscillate because of the external jet and ambient flow interactions. These oscillations are damped effectively by viscous and turbulent dissipations as one goes farther from the jet centreline and/or moves downstream. The position of separation point, oblique shock, and lambda shock structure angles are compared rigorously with experimental data of a two-dimensional convergent—divergent nozzle, and reasonable agreements are achieved.
Genetic algorithm-based design of transonic aerofoils using Euler equations
Authors: Lee J , Jang M
Published: November 2008

The paper describes the adaptation of genetic algorithms (GA) to the design of inviscid transonic aerofoils. GA is effective in optimization strategies for designing transonic aerofoils where the non-linear aerodynamic phenomenon of shock wave results in flow discontinuity. The Euler equations are discretized through the flux-vector splitting method with Poisson's equation-based grid generation. Advanced strategies in the GA such as directed crossover and multi-stage searches are employed in the context of function-based global optimization. The objective is to determine the best combination of weighted parameters of a analytic function for the aerofoil surface, by maximizing the L/ D ratio. The paper first covers the optimization of transonic aerofoils to enhance the baseline design of NACA0012. A two-point design problem is also conducted to accommodate both transonic and subsonic regimes represented by the Mach number and angle of attack. The optimized aerofoils have shown improved aerodynamic performance for both flight regimes.
Use of turbulence generators as stall-delaying devices in flight at low Reynolds numbers
Authors: Meseguer J , Sanz-Andrés A , Pérez-Grande I , Franchini S , Sanz J L , Ortega F , Chiappe L
Published: November 2008

Wings flying at low Reynolds numbers enter a stalled flow regime by laminar boundary layer separation at the leading edge. A way to improve the flying performance of these wings at the angle of attack close to stalling is by forcing the transition of the upper-side wing boundary layer from laminar flow to turbulent flow. To force such a transition several devices can be used, the simplest one being a wire parallel to the wing leading edge. The efficiency of such a turbulence generator has been checked by testing two wing models in a low turbulence wind tunnel. One of the wings is of elliptic planform and is equipped with a leading edge wire placed along 62 per cent of the wing span. The second model simulates the wing of the very primitive bird Archaeopteryx, and it is also equipped with a wire at the leading edge which simulates one of the long fingers emerging from the leading edge of the wings of this bird. In both cases, experimental results show that these leading-edge devices are effective in delaying wing stall.
Numerical analysis of the behaviour of repaired inclined cracks with bonded composite patch having two adhesive bands in aircraft structures
Authors: Bouiadjra B Bachir , Fekirini H , Belhouari M , Serier B
Published: November 2008

Adhesive in bonded composite repair plays two opposite roles. The first role ensures the load transfer between the composite patch and the cracked aluminium component. The second ensures the connection between these two structures in order to avoid adhesive failure. In this study, a method of adhesive deposition for repair is proposed, it divides the adhesive layer into two bands with different properties. The first band is used on the crack region to ensure stress transfer and the second is used beyond the crack region to avoid adhesive failure. The case of mixed mode loading (inclined crack) has been studied. The mode I and mode II stress intensity factors (SIFs) at the crack tip are computed for this repair configuration using the finite-element method. The obtained results show that the two SIFs at the crack tip are considerably reduced by the difference of properties between the two adhesive bands, which can improve the fatigue life of cracked structures.
Preliminary design optimization of profile losses in multi-stage axial compressors based on complex method
Authors: Taghavi-Zenouz R , Afzali S M
Published: November 2008

This paper illustrates a numerical technique undertaken for preliminary design optimization of profile losses in multi-stage axial compressors. Design process has been carried out based on one-dimensional row by row calculations along compressor mean line. The main objective of the optimization process was to find the best distribution of pressure ratios along compressor stages in order to maximize the overall efficiency, which is itself a non-linear function of governing variables. In this respect, only profile losses, identified as the most dominant ones, are focused on and minimized during the optimization process. Pressure ratios of stages have been taken as design variables. Diffusion factor and De Haller number of each blade row were considered as the main constraints during the optimization process. Numerical optimization was based on a sequential search technique, referred to as complex method. Design process in parallel to the numerical optimization is examined on a ten-stage axial compressor of known general performance data. Final results showed an increase of about 2.7 per cent in the total efficiency relative to its initial value calculated during the preliminary design process.
A numerical investigation into the effect of engine bleed on performance of a single-spool turbojet engine
Authors: Rahman N U , Whidborne J F
Published: November 2008

A real time simulation model has been developed to investigate the effect of variable engine bleed on steady state and transient performance of a single-spool turbojet engine. The bleed air is to be used for flow control on the aerodynamic control surfaces of a tailless configur-ation such as the blended wing body aircraft. The engine simulation uses the inter-component volume method and runs in MATLAB/Simulink environment. Bleed effects were simulated both with and without the control of engine speed. Experimental data for the advanced micro turbine (AMT) Olympus single-spool turbojet engine was used to validate the simulation results. Under nominal bleed conditions, the results were accurate to within 5 per cent of experimental values. While for excessive engine bleeds the results were accurate to within 10 per cent. The effect of engine bleed location along the compressor length was also incorporated. A proportional + integral speed controller with slew rate limiting was implemented as an integral part of the model. The method presented here could be easily expanded for steady state and transient performance simulation of two and three spool turbojet/turbofan engines.
Pricing and Market Concentration in Oligopoly Markets
Authors: Singh Vishal , Zhu Ting
Published: November 2008

This paper investigates the relationship between prices and market concentration in the auto rental industry. We assemble an original database that includes the number of auto rental operators and other exogenous demand and cost conditions at every commercial airport in the country. The data are interesting because we observe a large variation in market structure, ranging from more than 100 monopoly and duopoly markets to several competitive airports with more than eight firms. In addition, we collect daily rental prices in each market that are regressed against the number of operating firms and other control factors. Due to potential biases in treating market participants as exogenously assigned, we employ a two-stage estimation procedure in which an equilibrium model of endogenous market structure provides correction terms for the second-stage price regression. Results show that ignoring the endogeneity of market structure severely underestimates the impact of additional competitors on prices, with the competitive interaction parameters doubling in magnitude after the correction procedure. The downward bias in the competitive parameter can have important implications for horizontal mergers, which may incorrectly appear innocuous when using a model that ignores the endogeneity of market structure. More generally, our results serve as a warning on the potential biases to a large number of applications in marketing and economics that attempt to relate outcome variables such as prices, markups, or profits to the observed market structure.
Intervention Research with Youths at Elevated Risk for Suicide: Meeting the Ethical and Regulatory Challenges of Informed Consent and Assent
Authors: King Cheryl A. , Kramer Anne C.
Published: November 2008

Intervention research with youths at elevated risk for suicidal behavior and suicide—a vulnerable and high risk population—presents investigators with numerous ethical challenges. This report specifically addresses those challenges involving the informed consent and assent process with parents/guardians and youths. The challenges are delineated in the context of pertinent laws and regulatory requirements, and guidelines are suggested for their practical resolution. These are illustrated with case examples from NIMH‐funded intervention trials. Through the sharing of such methodological information, intervention researchers can support each other in conducting ethical research in a manner that does not unduly compromise scientific rigor.
Single‐Case Experimental Designs for the Evaluation of Treatments for Self‐Injurious and Suicidal Behaviors
Authors: Rizvi Shireen L. , Nock Matthew K.
Published: November 2008

Single‐case experimental designs (SCEDs) provide a time‐ and cost‐effective alternative to randomized clinical trials and offer significant advantages in terms of internal and external validity. A brief history and primer on SCEDs is provided, specifically for use in suicide intervention research. Various SCED methodologies, such as AB, ABAB, multiple baseline, and changing criterion designs, are described. Advantages and disadvantages of their use specifically for intervention research for suicidal and self‐injurious behaviors are detailed.
Behavioral Risk Assessment of the Guarded Suicidal Patient
Authors: Simon Robert I.
Published: November 2008

Psychiatrists and other mental health professionals are trained to assess patients by direct observation and examination. Short inpatient length of stay, brief outpatient visits, emergency room evaluations, and other time‐limited clinical settings require rapid assessment of suicide risk. Recognition of behavioral suicide risk factors can assist in the early identification of the guarded suicidal patient, thus avoiding total reliance on the patient's reporting.
Suicide Ideation and Attempts among Low‐Income African American Adolescents
Authors: Fitzpatrick Kevin M. , Piko Bettina F. , Miller Elizabeth
Published: November 2008

We examined the impact of risk and protective factors on the odds that African American adolescents seriously think about or attempt suicide. Data from students in grades 5–12 in a mostly urban, southeastern U.S. school district were analyzed. Findings support earlier work documenting differences in gender and grades. Risk factors were uniformly significant in understanding both ideation and attempts. Protective factors were not consistent predictors; the lowering role of religious protective factors was limited, though student's belonging to or their perception of belonging to a spiritual community was a significant factor in lowering the odds of suicide ideation.
A Review of “Suicidal Intent” Within the Existing Suicide Literature
Authors: Hasley Joseph P. , Ghosh Biswadip , Huggins Joseph , Bell Missy R. , Adler Lawrence E. , Shroyer A. Laurie W.
Published: November 2008

The results of a systematic literature review that investigated suicide intent are presented. Of the 44 relevant articles identified, 17 investigated the relationships between various suicide risk factors and suicide intent and 25 publications investigated the relationships between suicide intent and various suicide outcomes. Despite recent advancements in the definition and nomological validity of suicide intent, a high degree of variability in the empirical measurement and analysis of suicide intent was found. Such variability limits future research related to measuring suicidal risk and outcomes, reporting suicide intent, or the meaningful comparison of diagnostic approaches or treatments across multiple studies.
The Role of Attachment Styles and Interpersonal Problems in Suicide‐Related Behaviors
Authors: Stepp Stephanie D. , Morse Jennifer Q. , Yaggi Kirsten E. , Reynolds Sarah K. , Reed L. Ian , Pilkonis Paul A.
Published: November 2008

The relationships among adult attachment styles, interpersonal problems, and categories of suicide‐related behaviors (i.e., self‐harm, suicide attempts, and their co‐occurrence) were examined in a predominantly psychiatric sample (N = 406). Both anxious and avoidant attachment styles were associated with interpersonal problems. In turn, specific interpersonal problems differentially mediated the relations between attachment style and type of suicide‐related behaviors. These findings suggest the importance of distinguishing between these groups of behaviors in terms of etiological pathways, maintenance processes, and treatment interventions.
Survivors' Narratives of the Impact of Parental Suicide
Authors: Ratnarajah Dorothy , Schofield Margot J.
Published: November 2008

The impact of parental suicide on surviving children and their family system has received inadequate research attention. Using a qualitative narrative methodology with thematic analysis, we explored the short‐term and lifelong impact of parental suicide among 10 adults who, as children or adolescents, had lost a parent through suicide. The suicide triggered a wide range of structural and relational changes to the family, resulting in a cascading series of negative outcomes. These systemic issues are discussed and recommendations made about support structures for bereaved children and their families. Limitations of the study are discussed and future research directions identified.
Three Times Weekly Tacrolimus Ointment Reduces Relapse in Stabilized Atopic Dermatitis: A New Paradigm for Use
Authors: Paller Amy S. , Eichenfield Lawrence F. , Kirsner Robert S. , Shull Toni , Jaracz Eileen , Simpson Eric L. ,   for the US Tacrolimus Ointment Study Group
Published: November 2008

OBJECTIVE. Long-term, safe and effective therapeutic options for managing the chronic relapsing nature of atopic dermatitis are essential for improving patient quality of life. To minimize the risks of continued topical corticosteroid usage and potentially reduce the incidence of flares, we tested the efficacy and safety of a rotational paradigm of initial brief application of topical corticosteroid followed by long-term intermittent application of non-steroidal tacrolimus ointment to previously inflamed sites of dermatitis.

METHODS. In this 2-phase study, patients who were 2 to 15 years of age and had moderate to severe atopic dermatitis were randomly assigned to 4 days of twice-daily double-blind therapy with either alclometasone ointment 0.05% or tacrolimus ointment 0.03% (Phase I acute), followed by up to 16 weeks of twice-daily open-label tacrolimus ointment 0.03% (Phase I short-term). Patients whose disease stabilized underwent new randomization to double-blind tacrolimus ointment 0.03% or vehicle applied once daily, 3 times per week to clinically normal-appearing skin for up to 40 weeks (Phase II). Corticosteroid use was prohibited.

RESULTS. Of 206 randomly assigned patients, 152 completed Phase I; 105 of 152 were randomly assigned into Phase II (68 tacrolimus ointment and 37 vehicle). There were no differences in adverse events between alclometasone and tacrolimus (Phase I) or between tacrolimus and vehicle (Phase II). In the acute period, alclometasone-treated patients showed greater improvement in atopic dermatitis signs and symptoms; thereafter, when all patients applied tacrolimus ointment (short-term), there were no differences. In Phase II, tacrolimus-treated patients had significantly more disease-free days compared with vehicle, significantly longer time to first relapse, and significantly fewer disease relapse days.

CONCLUSIONS. For patients with stabilized moderate to severe atopic dermatitis, long-term intermittent application of tacrolimus ointment to normal-appearing but previously affected skin was significantly more effective than vehicle at maintaining disease stabilization, with a safety profile similar to vehicle.
Is it all tough talking at the top?
Authors: Baxter Judith
Published: November 2008

This paper uses a feminist post-structuralist approach to examine the gendered identities of a sample of British business leaders in Britain. While recent national surveys offer many material reasons why women are acutely under-represented as business leaders, the role of language is rarely addressed. This paper explores the ways in which ten senior women and men construct their sense of leadership identities through the medium of interview narratives. Drawing upon two poststructuralist models of analysis— Derrida’s (1987) theory of deconstruction and Sheldon’s (1992) concept of double-voice discourse, the paper shows how both females and males are able to shift pragmatically between interwoven corporate discourses, which demand competing cultural allegiances from one moment to the next— allegiances constantly tested by the rapid change and uncertainty that characterises global business. However, while male leaders experience a relative freedom of movement between different cultural discourses, female leaders are circumscribed by negative and reductive representations of female speech and behaviour. In sum, senior women are required constantly to observe, review, police and repair their use of leadership language, which potentially undermines their confidence and authority as leaders.
History Matching for Determination of Fracture Permeability and Capillary Pressure
Authors: Gang Tao , Kelkar Mohan
Published: November 2008

For naturally fractured reservoirs, it is very difficult to quantify future prediction without proper fracture properties, including such factors as fracture permeability, fracture orientation, and fracture length, and capillary pressure. Capillary pressure and fracture permeability can interact in a way that can produce nonunique results. Evaluation of core data may provide us with some information about imbibition capillary pressure curves; however, quantification of fracture permeability is determined largely by matching production data.

This paper presents an integrated approach to history matching naturally fractured reservoirs by adjusting the fracture permeability of individual fractures and water/oil capillary pressure curves. This paper is focused mainly on history-matching procedure and not on geological-model construction. By minimizing an objective function to history matching production data, we generate estimates of fracture permeability of individual fractures and water/oil capillary pressure curves. All implementations were incorporated into a commercial simulator and iterated in the automatic-history-matching scheme. The adjoint method and an efficient direct solver were used to reduce CPU time for calculating the sensitivity-coefficient matrix. A 2D synthetic case was used, with the fracture distribution from a Middle East reservoir, to validate this method.
Designing Hydraulic Fractures in Russian Oil and Gas Fields To Accommodate Non-Darcy and Multiphase Flow
Authors: Dedurin Andrey V. , Majar Vadim A. , Voronkov Andrey A. , Zagurenko Alexey G. , Zakharov Alexander Y. , Palisch Terry , Vincent M. C.
Published: November 2008

Non-Darcy and multiphase flow effects in hydraulic fractures have been well documented in the last several years. The pressure losses caused by these phenomena are accepted widely to be of great significance in most gas-well completions in the United States and elsewhere (Palisch et al. 2007; Forchheimer 1901; Milton-Tayler 1993a; Penny and Jin 1995; Flowers et al. 2003; Miskimins et al. 2005; Handren et al. 2001; Lolon et al. 2004; Vincent 2004; Olson et al. 2004). Although the importance in gas wells is evident, the authors pose the question of whether non-Darcy and multiphase flow effects are of concern in typical oil wells in Russia.

For the analysis, the authors evaluate three primary categories of Russian production wells: gas wells, oil wells producing above the bubblepoint, and oil wells producing below the bubblepoint. For each category, the authors describe the significance of non-Darcy and multiphase flow effects by use of the fracture-flow theory and state-of-the-art fracture-production models. This paper will illustrate that non-Darcy and multiphase flow effects can substantially decrease the production potential of gas wells and the many oil wells found in Russia that are producing below the bubblepoint.

Historically, Russian oil wells have been operated intentionally above the bubblepoint. However, more-aggressive well designs have recently been shown to increase production more than threefold. The authors explore the economics of producing these wells below the bubblepoint and show that for these more aggressive strategies, the effects of non-Darcy and multiphase flow can be significant and should be accommodated during fracture design.

The authors propose solutions for mitigating these effects with various modifications to the fracture design, including the impact of proppant selection on performance. Several operators within Russia have already successfully accounted for these phenomena in their fracture designs, and new field examples are explored, analyzed, and presented in the paper. Recent field results are presented for Gazpromneft's Achimovskoya formation BV8 in the Tomsk region (western Siberia) and BP-TNK's field near Buzuluk in the Orenburg region (Volga-Urals). The results found here are compared to published results from the Achimovskoya sandstone in the Kalchinskoye oil field, the BP12 formation of the Vyngayakhinskoe oil field, the Priobskoye and Sugmutskoe oil fields, and Gazprom's Yamburgskoe gas-condensate development.
A New Rate-Allocation-Optimization Framework
Authors: Güyagüler B. , Byer T.
Published: November 2008

Determination of the operating conditions of a field under a set of physical system constraints (e.g., compressor limits) and engineering preferences (e.g., voidage replacement) is a primary concern for petroleum engineers. Rule-based systems have been proposed for this, but the process is most suitably defined as an optimization problem. An optimization procedure that uses mixed-integer linear programming (MILP) is discussed in this study. Well rates that honor system and engineering constraints are handled simultaneously while the maximum for an objective is calculated (e.g., field oil rate or cash revenue). Optimal rates for the current conditions of the field are determined. Note that this results in instantaneous optimization and, thus, cannot account for recurrent events such as water breakthrough. Nevertheless, an efficient and robust instantaneous optimizer is useful within a grander optimization scheme, short forecast periods and, also, in real-time allocation situations. The approach is able to efficiently handle the nonlin-earities in the system by way of piecewise linear functions. Also, as a result of the formulation, the exact optimal solution of the problem is guaranteed. Another property of the approach is that, in cases in which it is not possible to honor all the targets and limits of the system simultaneously, a scheme is introduced that enables the engineer to prioritize the constraints. This prioritization scheme proves to be of great practical significance because most real cases have conflicting targets and limits that result in optimization systems with no feasible solutions. Also, a heuristic is used that ensures realistic results by elimination of mathematical artifacts (rate oscillations in time) that often arise when the reservoir contains wells with similar properties [e.g., water/oil ratio (WOR) and gas/ oil ratio (GOR)]. The optimization system is applied to synthetic cases and two real-field cases. The real-field cases pose problems that cannot be handled by conventional rule-based systems.
Inferring Interwell Connectivity from Well Bottomhole-Pressure Fluctuations in Waterfloods
Authors: Dinh Anh , Tiab Djebbar
Published: November 2008

This paper presents a new procedure to determine interwell connectivity in a reservoir on the basis of fluctuations of bottomhole pressure of both injectors and producers in a waterflood. The method uses a constrained multivariate linear-regression (MLR) analysis to obtain information about permeability trends, channels, and barriers.

Previous authors applied the same analysis to injection and production rates to infer connectivity between wells. In order to obtain good results, however, they applied various diffusivity filters to the flow-rate data to account for the time lags and the attenuation. This was a tedious process that requires subjective judgment. Shut-in periods in the data, usually unavoidable when a large number of data points were used, created significant errors in the results and were often eliminated from the analysis.

This new method yielded better results compared with the results obtained when production data were used. Its advantages include: (1) no diffusivity filters needed for the analysis, (2) minimal number of data points required to obtain good results, (3) and flexible plan to collect data because all constraints can be controlled at the surface. The new procedure was tested by use of a numerical reservoir simulator. Thus, different cases were run on two fields, one with five injectors and four producers and the other with 25 injectors and 16 producers.

For a large waterflood system, multiple wells are present and most of them are active at the same time. In this case, pulse tests or interference tests between two wells are difficult to conduct because the signal can be distorted by other active wells in the reservoir. In the proposed method, interwell connectivity can be obtained quantitatively from multiwell pressure fluctuations without running interference tests.