bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rural Residents with Disabilities Confront Substantial Barriers to Obtaining Primary Care
Authors: Iezzoni Lisa I. , Killeen Mary B. , O'Day Bonnie L. 
Published: March 2006

Objective.To learn about the health care experiences of rural residents with disabilities.Study Setting.Rural areas in Massachusetts and Virginia.Study Design.Local centers for independent living recruited 35 adults with sensory, physical, or psychiatric disabilities to participate in four focus group interviews.Data Collection Methods.Verbatim transcripts of interviews were reviewed to identify major themes.Principal Findings.Interviewees described the many well‐recognized impediments to health care in rural America; disability appears to exacerbate these barriers. Interviewees reported substantial difficulties finding physicians who understand their disabilities and sometimes feel that they must teach their local doctors about their underlying conditions. Interviewees described needing to travel periodically to large medical centers to get necessary specialty care. Many are poor and are either uninsured or have Medicaid coverage, complicating their searches for willing primary care physicians. Because many cannot drive, they face great difficulties getting to their local doctor and especially making long trips to urban centers. Available public transportation often is inaccessible and unreliable. Physicians' offices are sometimes located in old buildings that do not have accessible entrances or equipment. Based on their personal experiences, interviewees perceive that rural areas are generally less sensitive to disability access issues than urban areas.Conclusions.Meeting the health care needs of rural residents with disabilities will require interventions beyond health care, involving transportation and access issues more broadly.
Referrals to High‐Quality Cardiac Surgeons: Patients' Race and Characteristics of Their Physicians
Authors: Mukamel Dana B. , Weimer David L. , Mushlin Alvin I. 
Published: March 2006

Objective. To examine the referral process to cardiac surgeons in order to explain racial disparities in access to high‐quality cardiac surgeons.Data Sources/Study Settings. All white and black Medicare fee‐for‐service patients undergoing coronary artery bypass graft (CABG) surgery in New York State during 1997–1999.Study Design. A retrospective analysis of referral patterns for white and black patients in relation to the quality of the cardiac surgeon, measured by the surgeon's risk‐adjusted mortality rate (RAMR), and in relation to characteristics of the physician providing the majority of cardiac care before the surgery. The average RAMRs of the surgeons to whom different physicians referred patients were compared using t‐tests and paired t‐tests. A hierarchical multivariate regression model was estimated to test hypotheses about the effect of physicians' characteristics on referrals of blacks to low‐quality surgeons.Data Extraction Method. Variables were constructed from Medicare claims.Principal Findings. The differential in surgeons' quality for white and black patients is partially due to the physician providing the majority of cardiac care before the surgery. There is both across‐ and within‐physician variation in referrals. Of the physician characteristics investigated, only the number of black patients referred to CABG and the percent of all cardiac referrals to the same hospital decrease the difference in surgeons' quality between whites and blacks.Conclusions. Several different pathways lead blacks to cardiac surgeons of lower quality. Further research is needed to understand the causes and inform policies designed to minimize disparities in access to high‐quality providers.
State Regulation and the Delivery of Physical Therapy Services
Authors: Resnik Linda , Feng Zhanlian , Hart Dennis L. 
Published: March 2006

Objective.The study purpose was to examine the relationship between state regulations of physical therapists (PT) and three dependent variables: physical therapist assistant (PTA) utilization more than 50 percent of the time during the treatment episode (high PTA utilization), number of visits, and patient self‐reported functional health status (FHS) at discharge. We evaluated regulations governing licensure of PTAs, PT/PTA ratio, frequency of PT re‐evaluation, and PTA supervision.Data Source.The analytic sample included 63,900 patients from 38 states drawn from 395 clinics who participated in the Focus on Therapeutic Outcomes Inc. (Knoxville, TN) database in 2000 and 2001.Study Design.Using a Bayesian modeling approach with the Markov Chain Monte Carlo estimation method, we fitted separate multilevel multivariate regression models predicting high PTA utilization, number of visits, and discharge FHS.Data Collection Methods.Patients completed FHS surveys at intake and discharge. Clinicians recorded the number of visits and percentage of time a patient spent with each provider.Principal Findings.After controlling for patient, therapist, and clinic characteristics, the presence of state regulations regarding PTA supervision was not associated with the likelihood of high PTA utilization. High PTA utilization and regulations requiring full‐time onsite supervision were associated with more visits, whereas regulation of PT/PTA ratio was associated with fewer visits. Supervisory regulations were associated with better discharge FHS. High PTA utilization and use of therapy aides were associated with more visits per episode and lower discharge FHS.Conclusions.The use of care extenders in place of PTs is likely to result in less efficient and lower quality care in outpatient rehabilitation.
The Utility of Clinical Features in Patients Presenting With Nontraumatic Headache: An Investigation of Adult Patients Attending an Emergency Department
Authors: Locker Thomas E , Thompson Catriona , Rylance Jamie , Mason Suzanne M 
Published: March 2006

Objective.—When patients present to an emergency department because of nontraumatic headache, they often present a diagnostic challenge. This study aimed to examine the utility of clinical features in detecting serious underlying causes of nontraumatic headache in adult patients presenting to an emergency department.Methods.—A prospective observational study of alert adult patients presenting to 1 UK emergency department over a period of 14 months was conducted. Patients were excluded if their headache was related to trauma or they had been previously recruited into the study. A standardized data collection form was used to record details of the history and examination findings. Investigation and management were conducted according to the existing departmental protocols. Patients were followed up for 3 months following their initial presentation. Each factor in the history and examination was examined for its ability to predict a serious underlying cause of headache.Results.—Five hundred and eighty‐nine patients were included in the study with complete follow‐up details obtained on 558 (94.7%) patients. Seventy‐five (13.4%) patients were found to have a serious pathological cause of their headache. Four features were found to be significant independent predictors of serious pathology, these were age >50 years (likelihood ratio (LR) = 2.34), sudden onset, (LR = 1.74), any abnormality on neurological examination (LR = 3.56), and presentation due to associated features (LR = 2.27). Taken in combination, the presence of any 1 of the first 3 features has a sensitivity of 98.6% and specificity of 34.4% (Positive LR = 1.50, Negative LR = 0.04).Conclusion.—Three features, age greater than 50, sudden onset, and an abnormal neurological examination, are identified as significant independent predictors of serious pathology, which, in combination, can exclude the presence of such pathology in adult patients presenting with nontraumatic headache.
Effects of Energy Drink Ingestion on Alcohol Intoxication
Authors: Ferreira Sionaldo Eduardo , De Mello Marco Túlio , Pompéia Sabine , De Souza‐Formigoni Maria Lucia Oliveira 
Published: March 2006

Background: Well‐known reports suggest that the use of energy drinks might reduce the intensity of the depressant effects of alcohol. However, there is little scientific evidence to support this hypothesis.Objective and Methods: The present study aimed at evaluating the effects of the simultaneous ingestion of an alcohol (vodka37.5%v/v) and an energy drink (Red Bull®—3.57 mL/kg), compared with those presented after the ingestion of an alcohol or an energy drink alone. Twenty‐six young healthy volunteers were randomly assigned to 2 groups that received 0.6 or 1.0 g/kg alcohol, respectively. They all completed 3 experimental sessions in random order, 7 days apart: alcohol alone, energy drink alone, or alcohol plus energy drink. We evaluated the volunteers' breath alcohol concentration, subjective sensations of intoxication, objective effects on their motor coordination, and visual reaction time.Results: When compared with the ingestion of alcohol alone, the ingestion of alcohol plus energy drink significantly reduced subjects' perception of headache, weakness, dry mouth, and impairment of motor coordination. However, the ingestion of the energy drink did not significantly reduce the deficits caused by alcohol on objective motor coordination and visual reaction time. The ingestion of the energy drink did not alter the breath alcohol concentration in either group.Conclusions: Even though the subjective perceptions of some symptoms of alcohol intoxication were less intense after the combined ingestion of the alcohol plus energy drink, these effects were not detected in objective measures of motor coordination and visual reaction time, as well as on the breath alcohol concentration.
Policy, technology, and management strategies for achieving sustainable agricultural intensification
Authors: Lee David R. , Barrett Christopher B. , McPeak John G. 
Published: March 2006

AbstractConsiderable agreement exists among researchers, development practitioners, and policymakers regarding the goals of sustainable agricultural intensification (SAI). They include: achieving agricultural productivity growth, household food security, and improved rural livelihoods and employment, while simultaneously mitigating environmental degradation. However, the multiplicity of these objectives, as well as the choice of approaches to achieving them and the site‐ and context‐specificity of specific technological and institutional interventions, assures that the research and policy challenges to achieving SAI will remain considerable. This article summarizes the contributions of the articles in this Special Issue in four areas of the literature. First, labor market constraints, the labor intensity of specific agricultural technologies and practices, and labor's substitutability, or complementarity, with other inputs are shown to widely influence their viability and related input efficiencies. Second, the articles identify specific tradeoffs and synergistic relationships that arise in the attainment of these multiple goals stemming from technologies, management practices, and policies introduced under specific agroclimatic, market, and institutional conditions. Third, these papers contribute to the literature on agricultural technology adoption by furnishing additional empirical evidence on the determinants and effects of investment behavior and adoption of specific technologies and management practices. Finally, the articles in this Special Issue emphasize that there is no single policy nor technological, management, or institutional innovation that unambiguously promotes SAI. Preferred policies must be contextualized and sensitive to initial biophysical, market, and institutional conditions.
Deprived land‐use intensification in shifting cultivation: the population pressure hypothesis revisited
Authors: Pascual Unai , Barbier Edward B. 
Published: March 2006

AbstractThis article provides a theoretical framework, based on optimal control theory, to analyze farm households' land‐use intensification decisions in forest‐based shifting cultivation (slash‐and‐burn) agroecosystems. The main results from the analysis generally coincide with the “Population Pressure Hypothesis” (PPH) as an important driver of soil degradation due to the so‐called “fallow crisis” or “deprived land‐use intensification” in shifting cultivation. However, the model also shows, from a supply perspective, that such a vicious circle of lower yields and greater forest land clearing may be avoided when the production elasticity of on‐farm labor outweighs the elasticity of substitution between farm labor and soil fertility. Furthermore, using data from shifting cultivating households from Yucatán, Mexico, we calibrate the effect of changes in population density. The numerical analysis suggests that by contrast to better‐off households, when population density increases, poorer shifting cultivating households' optimal labor allocation strategy is to further extensify land use by clearing more forest in the village common property land, or ejido land.
Strategies for sustainable intensification in East African highlands: labor use and input efficiency
Authors: Ruben Ruerd , Kruseman Gideon , Kuyvenhoven Arie 
Published: March 2006

AbstractStrategies for poverty alleviation and sustainable natural resource management usually focus on land use options for improving yields. Increasing the returns to critical factors requires possibilities for input substitution. Inadequate timing of input applications or nonavailability of complementary factors can seriously hinder this substitution. Such constraints particularly apply in less‐favored areas where soil organic matter content is too low for enabling efficient nutrient uptake and soil structure limits water infiltration and moisture retention.This article focuses attention on the importance of labor for crop management activities and input applications that enhance input efficiency in highland area cropping systems of Northern Ethiopia. Given the inherent complementarities between labor and nutrient supply during critical phases of the plant growth process, input efficiency strongly depends on labor use. We present a semiparametric bioeconomic modeling approach to analyze the available options for improving input efficiency in agricultural production. Input response equations are used that consider the returns per unit of land and labor as a function of specific combinations of material inputs and management practices. Critical trade‐offs may arise when opportunity costs for labor are considered or when complementary factors appear as binding constraints. The model enables assessment of feasible pathways for enhancing sustainable intensification and poverty alleviation in typical settings of the East African highland region.
Skin layer‐specific transcriptional profiles in normal and recessive yellow (Mc1re/Mc1re) mice
Authors: April Craig S. , Barsh Gregory S. 
Published: March 2006

SummaryThe melanocortin 1 receptor (Mc1r) plays a central role in cutaneous biology, but is expressed at very low levels by a small fraction of cells in the skin. In humans, loss‐of‐function MC1R mutations cause fair skin, freckling, red hair, and increased predisposition to melanoma; in mice, Mc1r loss‐of‐function is responsible for the recessive yellow mutation, associated with pheomelanic hair and a decreased number of epidermal melanocytes. To better understand how Mc1r signaling affects different cutaneous phenotypes, we examined large‐scale patterns of gene expression in different skin components (whole epidermal sheets, basal epidermal cells and whole skins) of neonatal (P2.5) normal and recessive yellow mice, starting with a 26K mouse cDNA microarray. From c. 17 000 genes whose levels could be accurately measured in neonatal skin, we identified 883, 2097 and 552 genes that were uniquely expressed in the suprabasal epidermis, basal epidermis and dermis, respectively; specific biologic roles could be assigned for each class. Comparison of normal and recessive yellow mice revealed 69 differentially expressed genes, of which the majority had not been previously implicated in Mc1r signaling. Surprisingly, many of the Mc1r‐dependent genes are expressed in cells other than melanocytes, even though Mc1r expression in the skin is confined almost exclusively to epidermal melanocytes. These results reveal new targets for Mc1r signaling, and point to a previously unappreciated role for a Mc1r‐dependent paracrine effect of melanocytes on other components of the skin.
Regulation of pigmentation in zebrafish melanophores
Authors: Logan Darren W. , Burn Sally F. , Jackson Ian J. 
Published: March 2006

SummaryIn comparison with the molecular genetics of melanogenesis in mammals, the regulation of pigmentation in poikilothermic vertebrates is poorly understood. Mammals undergo morphological colour change under hormonal control, but strikingly, many lower vertebrates display a rapid physiological colour change in response to the same hormones. The recent provision of extensive genome sequencing data from teleost zebrafish, Danio rerio, provides the opportunity to define the genes and proteins mediating this physiological pigment response and characterise their function biologically. Here, we illustrate the background adaptation process in adults and larvae and describe a novel assay to visualize and directly quantify the rate of zebrafish melanophore pigment translocation in unprecedented detail. We demonstrate the resolution of this assay system; quantifying the zebrafish melanophore response to melanin‐concentrating and melanocyte‐stimulating hormones. Furthermore, we investigate the intracellular signalling downstream of hormone stimulation and the biomechanical processes involved in zebrafish pigment translocation, confirming the importance of cyclic adenosine monophosphate (cAMP) as a mediator of pigment translocation and finding intact microtubules are essential for both melanin dispersion and aggregation in zebrafish, but that microfilament disruption affects aggregation only. In conclusion, we propose these data establish the zebrafish as an experimental model for studying both physiological colour change and the molecular basis of pigment translocation.
Elastic-Plastic Contact Behavior Considering Asperity Interactions for Surfaces With Various Height Distributions
Authors: Jeng Yeau-Ren , Peng Shin-Rung 
Published: March 2006

AbstractThis study investigates the effects of asperity interactions on the mean surface separation and the real contact area for rough surfaces with non-Gaussian height distributions. The effects of the asperity interactions on the local deformation behavior of a given microcontact are modeled using the Saint Venant principle and Love’s formula. The non-Gaussian rough surfaces are described by the Johnson translatory system. The results indicate that asperity interactions can significantly affect the mean separation of surfaces with non-Gaussian height distributions. The findings also reveal that the contact load and the real contact area of surfaces with non-Gaussian height distributions are significantly different from those of surfaces with Gaussian height distributions. This study uncovers that skewed surfaces tend to deform more elastically, which provides underlying physics for the long-time conventional wisdom and recent experimental data [Y. R. Jeng, 1996, Tribol. Trans., 39, 354–361;Y. R. Jeng, Z. W. Lin, and S. H. Shyo, 2004, ASME J. Tribol., 126, 620–625] that running-in surfaces have better wear resistance.
Influence of Inlet Oil Temperature on the Instability Threshold of Rotor-Bearing Systems
Authors: Wang J. K. , Khonsari M. M. 
Published: March 2006

AbstractThe existing literature contains a number of disparities in assessing the effect of inlet oil temperature on the instability threshold speed in hydrodynamic journal bearings. Specifically, some papers have presented evidence that lowering the inlet oil temperature tends to have a stabilizing effect, whereas others have shown the opposite. No clear explanation has been offered for this phenomenon. This paper presents the results of a series of experiments that explain the nature of these disparities and sheds light on the effect of the inlet oil temperature on the instability threshold in hydrodynamic journal bearings.
Elastic-Plastic Contact Between Rough Surfaces: Proposal for a Wear or Running-In Model
Authors: Nélias D. , Boucly V. , Brunet M. 
Published: March 2006

Abstract
A semi-analytical thermo-elastic-plastic contact model has been recently developed and presented in a companion paper. The main advantage of this approach over the classical finite element method (FEM) is the treatment of transient problems with the use of fine meshing and the possibility of studying the effect of a surface defect on the surface deflection as well as on subsurface stress state. A return-mapping algorithm with an elastic predictor/plastic corrector scheme and a von Mises criterion is now used, which improves the plasticity loop. This improvement in the numerical algorithm increases the computing speed significantly and shows a much better convergence and accuracy. The contact model is validated through a comparison with the FEM results of Kogut and Etsion (2002, J. Appl. Mech., 69, pp. 657–662) which correspond to the axisymmetric contact between an elastic-perfectly plastic sphere and a rigid flat. A model for wear prediction based on the material removal during cyclic loading is then proposed. Results are presented, first, for initially smooth surfaces and, second, for rough surfaces. The effects of surface shear stress and hardening law are underlined.
A Lattice-Based Cellular Automata Modeling Approach for Granular Flow Lubrication
Authors: Jasti Venkata K. , Higgs C. Fred 
Published: March 2006

Abstract
Liquid lubricants break down at extreme temperatures and promote stiction in micro-/nanoscale environments. Consequently, using flows of solid granular particles as a “dry” lubrication mechanism in sliding contacts was proposed because of their ability to carry loads and accommodate surface velocities. Granular flows are highly complex flows that in many ways act similar to fluids, yet are difficult to predict because they are not well understood. Granular flows are composed of discrete particles that display liquid and solid lubricant behavior with time. This work describes the usefulness of employing lattice-based cellular automata (CA), a deterministic rule-based mathematics approach, as a tool for modeling granular flows in tribological contacts. In the past work, granular flows have been modeled using the granular kinetic lubrication (GKL) continuum modeling approach. While the CA modeling approach is constructed entirely from rules, results are in good agreement with results from the GKL model benchmark results. Velocity results of the CA model capture the well-known slip behavior of granular flows near boundaries. Solid fraction results capture the well-known granular flow characteristic of a highly concentrated center region. CA results for slip versus roughness also agree with GKL theory.