Browse Health
Dr. Robert Butler, MD
Internist, Emergency Physician
28 years of experience
Video profile
Accepting new patients

Education ?

Medical School Score Rankings
Northwestern University (1982)
  • Currently 3 of 4 apples
Top 50%

Awards & Distinctions ?

Awards  
Patients' Choice Award (2008 - 2009, 2011 - 2014)
Compassionate Doctor Recognition (2011 - 2013)
Associations
American Board of Internal Medicine

Affiliations ?

Dr. Butler is affiliated with 2 hospitals.

Hospital Affilations

Score

Rankings

  • Mercy Medical Center, Merced - Community Campus
    301 E 13th St, Merced, CA 95341
    • Currently 3 of 4 crosses
    Top 50%
  • Mercy Medical Center Merced
    2740 M St, Merced, CA 95340
  • Publications & Research

    Dr. Butler has contributed to 58 publications.
    Title The Effect of Total Hip Arthroplasty Surgical Approach on Postoperative Gait Mechanics.
    Date January 2012
    Journal The Journal of Arthroplasty
    Excerpt

    Surgical approach for total hip arthroplasty (THA) is determined by clinician preference from limited prospective data. This study aimed to examine the effect of surgical approach (direct lateral, posterior, and anterolateral) on 6-week postoperative gait mechanics. Thirty-five patients (direct lateral, 8; posterior, 12; anterolateral, 15) were tested preoperatively and 6 weeks after THA. Patients underwent a gait analysis at a self-selected walking speed. A 2-way analysis of variance was used for analysis. Stride length, step length, peak hip extension, and walking speed increased after THA. The 3 surgical approach variables were not significantly different for any of the study variables after THA. All patients showed some increase in selected variables after THA regardless of surgical approach. In this study, surgical approach did not appear to significantly influence the early postoperative gait mechanics that were quantified.

    Title Frontal-plane Gait Mechanics in People with Medial Knee Osteoarthritis Are Different from Those in People with Lateral Knee Osteoarthritis.
    Date September 2011
    Journal Physical Therapy
    Excerpt

    The majority of research on gait mechanics in knee osteoarthritis has focused on people with medial compartment involvement. As a result, little is known about the gait mechanics of people with the less common, lateral compartment disease.

    Title The Reliability of an Instrumented Device for Measuring Components of the Star Excursion Balance Test.
    Date July 2011
    Journal North American Journal of Sports Physical Therapy : Najspt
    Excerpt

    The Star Excursion Balance Test (SEBT) is a dynamic test that requires strength, flexibility, and proprioception and has been used to assess physical performance, identify chronic ankle instability, and identify athletes at greater risk for lower extremity injury. In order to improve the repeatability in measuring components of the SEBT, the Y Balance Test™ has been developed.

    Title Sea Level, Dinosaur Diversity and Sampling Biases: Investigating the 'common Cause' Hypothesis in the Terrestrial Realm.
    Date July 2011
    Journal Proceedings. Biological Sciences / The Royal Society
    Excerpt

    The fossil record is our primary window onto the diversification of ancient life, but there are widespread concerns that sampling biases may distort observed palaeodiversity counts. Such concerns have been reinforced by numerous studies that found correlations between measures of sampling intensity and observed diversity. However, correlation does not necessarily mean that sampling controls observed diversity: an alternative view is that both sampling and diversity may be driven by some common factor (e.g. variation in continental flooding driven by sea level). The latter is known as the 'common cause' hypothesis. Here, we present quantitative analyses of the relationships between dinosaur diversity, sampling of the dinosaur fossil record, and changes in continental flooding and sea level, providing new insights into terrestrial common cause. Although raw data show significant correlations between continental flooding/sea level and both observed diversity and sampling, these correlations do not survive detrending or removal of short-term autocorrelation. By contrast, the strong correlation between diversity and sampling is robust to various data transformations. Correlations between continental flooding/sea level and taxic diversity/sampling result from a shared upward trend in all data series, and short-term changes in continental flooding/sea level and diversity/sampling do not correlate. The hypothesis that global dinosaur diversity is tied to sea-level fluctuations is poorly supported, and terrestrial common cause is unsubstantiated as currently conceived. Instead, we consider variation in sampling to be the preferred null hypothesis for short-term diversity variation in the Mesozoic terrestrial realm.

    Title Biomechanical Analysis of the Different Classifications of the Functional Movement Screen Deep Squat Test.
    Date March 2011
    Journal Sports Biomechanics / International Society of Biomechanics in Sports
    Excerpt

    The purpose of this study is to examine the peak sagittal plane joint angles and joint moments of the lower extremity during the deep squat (DS) movement of the Functional Movement Screen (FMS) to assess differences between the classifications (1,2,3). Twenty-eight participants volunteered for the study and were screened to assess their FMS score on the DS task. All participants underwent a quantitative movement analysis performing the FMS DS movement at a self-selected speed. The participants in Group 3 exhibited greater dorsiflexion excursion compared to those in Group 1. Participants in Group 3 had greater peak knee flexion and knee flexion excursion than those in Group 2 who exhibited more than the participants in Group 1. Group 3 also exhibited a greater peak knee extension moment compared to Group 1. At the hip, Groups 3 and 2 exhibited greater peak hip flexion, hip flexion excursion and peak hip extension moment compared to Group 1. Thus, it appears that individuals who score differently on the deep squat as determined by the FMS exhibit differences in mechanics that may be beneficial in assessing strategies for interventions. Future research should assess how fundamental changes in mobility and stability independently affect DS performance.

    Title Gait Mechanics After Acl Reconstruction: Implications for the Early Onset of Knee Osteoarthritis.
    Date June 2010
    Journal British Journal of Sports Medicine
    Excerpt

    Individuals who sustain a rupture of the anterior cruciate ligament (ACL) are at an increased risk for developing early-onset knee osteoarthritis (OA). The mechanism behind the early onset of the disease is still unknown. Knee OA progression has been previously examined by calculating the internal knee-abduction moment during gait. However, knee-joint moments have not been examined in individuals after ACL reconstruction as a potential mechanism for disease progression in early knee OA.

    Title Mesozoic Marine Tetrapod Diversity: Mass Extinctions and Temporal Heterogeneity in Geological Megabiases Affecting Vertebrates.
    Date May 2010
    Journal Proceedings. Biological Sciences / The Royal Society
    Excerpt

    The fossil record is our only direct means for evaluating shifts in biodiversity through Earth's history. However, analyses of fossil marine invertebrates have demonstrated that geological megabiases profoundly influence fossil preservation and discovery, obscuring true diversity signals. Comparable studies of vertebrate palaeodiversity patterns remain in their infancy. A new species-level dataset of Mesozoic marine tetrapod occurrences was compared with a proxy for temporal variation in the volume and facies diversity of fossiliferous rock (number of marine fossiliferous formations: FMF). A strong correlation between taxic diversity and FMF is present during the Cretaceous. Weak or no correlation of Jurassic data suggests a qualitatively different sampling regime resulting from five apparent peaks in Triassic-Jurassic diversity. These correspond to a small number of European formations that have been the subject of intensive collecting, and represent 'Lagerstätten effects'. Consideration of sampling biases allows re-evaluation of proposed mass extinction events. Marine tetrapod diversity declined during the Carnian or Norian. However, the proposed end-Triassic extinction event cannot be recognized with confidence. Some evidence supports an extinction event near the Jurassic/Cretaceous boundary, but the proposed end-Cenomanian extinction is probably an artefact of poor sampling. Marine tetrapod diversity underwent a long-term decline prior to the Cretaceous-Palaeogene extinction.

    Title Effect of Laterally Wedged Foot Orthoses on Rearfoot and Hip Mechanics in Patients with Medial Knee Osteoarthritis.
    Date July 2009
    Journal Prosthetics and Orthotics International
    Excerpt

    The purpose of this study was to examine the effects of laterally wedged foot orthotic devices, used to treat knee osteoarthritis, on frontal plane mechanics at the rearfoot and hip during walking. Thirty individuals with diagnosed medial knee osteoarthritis were recruited for this study. Three dimensional kinematics and kinetics were recorded as the subjects walked in the laboratory at an intentional walking speed. Peak eversion, eversion excursion and peak eversion moment were increased while the peak knee adduction moment was reduced in the laterally wedged orthotic condition compared to the no wedge condition. In contrast, no changes were observed in the variables of interest at the hip. There was no significant relationship between the change in the peak frontal plane moment at the rearfoot and change in the peak frontal plane moment at the knee or hip as a result of the lateral wedge. Laterally wedged foot orthotic devices, used to treat knee osteoarthritis, do not influence hip mechanics. However, they do result in increased rearfoot eversion and inversion moment. Therefore, a full medical screen of the foot should occur before laterally wedged foot orthotic devices are prescribed as a treatment for knee osteoarthritis.

    Title Footwear and Running Cardio-respiratory Responses.
    Date July 2009
    Journal International Journal of Sports Medicine
    Excerpt

    This study compared cardio-respiratory responses during running wearing a motion control shoe (MC) or a cushioning shoe (CU) in a cross-over single blinded design. Fourteen runners (10F/4M, age=27.3+/-5.1 years, body mass=64.1+/-12.2 kg, height=167.8+/-7.5 cm, VO (2)max=52.3+/-8.8 ml/kg/min) completed a 40-min run at approximately 65% VO (2) max under both shoe conditions. Oxygen uptake (mL/kg/min; L/min), minute ventilation (L/min), respiratory exchange ratio, and heart rate were measured at minutes 8-10, 18-20, 28-30 and 38-40 of exercise. Rating of perceived exertion was obtained at minutes 10, 20, 30 and 40. Two (footwear) by four (time) repeated measures ANOVAs showed no differences between footwear conditions in overall oxygen consumption (MC=36.8+/-1.5 vs. CU=35.3+/-1.4 mL/kg/min, p=0.143), minute ventilation (MC=50.4+/-4 vs. CU=48.5+/-3.8, p=0.147), respiratory exchange ratio (MC=0.90+/-0.01 vs. CU=0.89+/-0.01, p=0.331), heart rate (MC=159+/-3 vs. CU=160+/-3, p=0.926), or rate of perceived exertion. The design of motion control footwear does not appear to affect cardio-respiratory or perceived exertion responses during submaximal running. The findings are specific to the shoes tested. Nonetheless, the outcomes suggest that footwear selection to reduce certain overuse injuries does not increase the work of running.

    Title Diversity Patterns Amongst Herbivorous Dinosaurs and Plants During the Cretaceous: Implications for Hypotheses of Dinosaur/angiosperm Co-evolution.
    Date April 2009
    Journal Journal of Evolutionary Biology
    Excerpt

    Palaeobiologists frequently attempt to identify examples of co-evolutionary interactions over extended geological timescales. These hypotheses are often intuitively appealing, as co-evolution is so prevalent in extant ecosystems, and are easy to formulate; however, they are much more difficult to test than their modern analogues. Among the more intriguing deep time co-evolutionary scenarios are those that relate changes in Cretaceous dinosaur faunas to the primary radiation of flowering plants. Demonstration of temporal congruence between the diversifications of co-evolving groups is necessary to establish whether co-evolution could have occurred in such cases, but is insufficient to prove whether it actually did take place. Diversity patterns do, however, provide a means for falsifying such hypotheses. We have compiled a new database of Cretaceous dinosaur and plant distributions from information in the primary literature. This is used as the basis for plotting taxonomic diversity and occurrence curves for herbivorous dinosaurs (Sauropodomorpha, Stegosauria, Ankylosauria, Ornithopoda, Ceratopsia, Pachycephalosauria and herbivorous theropods) and major groups of plants (angiosperms, Bennettitales, cycads, cycadophytes, conifers, Filicales and Ginkgoales) that co-occur in dinosaur-bearing formations. Pairwise statistical comparisons were made between various floral and faunal groups to test for any significant similarities in the shapes of their diversity curves through time. We show that, with one possible exception, diversity patterns for major groups of herbivorous dinosaurs are not positively correlated with angiosperm diversity. In other words, at the level of major clades, there is no support for any diffuse co-evolutionary relationship between herbivorous dinosaurs and flowering plants. The diversification of Late Cretaceous pachycephalosaurs (excluding the problematic taxon Stenopelix) shows a positive correlation, but this might be spuriously related to poor sampling in the Turonian-Santonian interval. Stegosauria shows a significant negative correlation with flowering plants and a significant positive correlation with the nonflowering cycadophytes (cycads, Bennettitales). This interesting pattern is worthy of further investigation, and it reflects the decline of both stegosaurs and cycadophytes during the Early Cretaceous.

    Title Palaeoenvironmental Controls on the Distribution of Cretaceous Herbivorous Dinosaurs.
    Date March 2009
    Journal Die Naturwissenschaften
    Excerpt

    Previous attempts to determine palaeoenvironmental preferences in dinosaurs have generally been qualitative assessments based upon data from restricted geographical areas. Here, we use a global database of Cretaceous herbivorous dinosaurs to identify significant associations between clades and broad palaeoenvironmental categories ('terrestrial', 'coastal', 'marine'). Nodosaurid ankylosaurs and hadrosaurids show significant positive associations with marine sediments, while marginocephalians (Ceratopsia, Pachycephalosauria), saurischians (herbivorous theropods, Sauropoda) and ankylosaurid ankylosaurs are significantly positively associated with terrestrial sediments. These results provide quantitative support for the hypothesis that some clades (Nodosauridae, Hadrosauridae) were more abundant in coastal and/or fluvial environments, while others (e.g. Marginocephalia, Ankylosauridae) preferentially inhabited more distal environments.

    Title Satisfaction with Low Back Pain Care.
    Date August 2008
    Journal The Spine Journal : Official Journal of the North American Spine Society
    Excerpt

    BACKGROUND: By using a unique, prospective study of occupational back pain claims, we examined health-care satisfaction by provider type and its effect on return to work. PURPOSE: We estimated satisfaction differentials by provider type, decomposing overall satisfaction into two components: bedside manner and effectiveness of care. We also examined how health-care satisfaction affects the duration of jobless claims. STUDY DESIGN: The Arizona State University Healthy Back Study (HBS) is a prospective study of work-related back pain; 1,831 workers completed a baseline interview, with follow-up interviews at 1 month, 6 months, and 1 year. The HBS merged demographic and claim characteristics from the workers' compensation claim files with self-reported severity measures, measures of satisfaction, and postonset employment from worker interviews. OUTCOME MEASURES: Overall and detailed satisfaction with treatment and workers' compensation claim duration. METHODS: We performed a nonparametric descriptive analysis of satisfaction by provider type and used multivariate regressions to decompose overall satisfaction into component parts. The duration analysis links differentials in health care satisfaction to differences in claim durations. RESULTS: Workers treated by surgeons, chiropractors (DCs), or physical therapists are more satisfied with their health care than those treated by MDs. Workers are more concerned with the effectiveness of care than with the bedside manner of their provider. A one standard deviation improvement in satisfaction with the health-care provider reduces claim duration by about 25%. CONCLUSIONS: Satisfaction with health care has a significant impact on jobless spells and varies significantly between provider types.

    Title Arch Height Index Measurement System: Establishment of Reliability and Normative Values.
    Date July 2008
    Journal Journal of the American Podiatric Medical Association
    Excerpt

    The purposes of this study were 1) to determine the intrarater and interrater reliability of the arch height index measurement system device, 2) to establish population normative values for the arch height index in recreational runners, and 3) to compare arch height index values between the right and left feet and between genders.

    Title Patterns of Sick-leave and Health Outcomes in Injured Workers with Back Pain.
    Date June 2008
    Journal European Spine Journal : Official Publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society
    Excerpt

    Little is known about the sick-leave experiences of workers who make a workers' compensation claim for back pain. Our objective is to describe the 1-year patterns of sick-leave and the health outcomes of a cohort of workers who make a workers' compensation claim for back pain. We studied a cohort of 1,831 workers from five large US firms who made incident workers' compensation claims for back pain between January 1, 1999 and June 30, 2002. Injured workers were interviewed 1 month (n = 1,321), 6 months (n = 810) and 1 year (n = 462) following the onset of their pain. We described the course of back pain using four patterns of sick-leave: (1) no sick-leave, (2) returned to worked and stayed, (3) multiple episodes of sick-leave and (4) not yet returned to work. We described the health outcomes as back and/or leg pain intensity, functional limitations and health-related quality of life. We analyzed data from participants who completed all follow-up interviews (n = 457) to compute the probabilities of transition between patterns of sick-leave. A significant proportion of workers experienced multiple episodes of sick-leave (30.2%; 95% CI 25.0-35.1) during the 1-year follow-up. The proportion of workers who did not report sick-leave declined from 42.4% (95% CI 39.0-46.1) at 1 month to 33.6% (28.0-38.7) at 1 year. One year after the injury, 2.9% (1.6-4.9) of workers had not yet returned to work. Workers who did not report sick-leave and those who returned and stayed at work reported better health outcomes than workers who experienced multiple episodes of sick-leave or workers who had not returned to work. Almost a third of workers with an incident episode of back pain experience recurrent spells of work absenteeism during the following year. Our data suggest that stable patterns of sick-leave are associated with better health.

    Title Timing Makes a Difference: Early Nurse Case Management Intervention and Low Back Pain.
    Date February 2008
    Journal Professional Case Management
    Excerpt

    PURPOSE OF STUDY: * To examine whether early nurse contacts influenced workers' satisfaction with their nurse case management, their healthcare, and the way the firm was treating their injury.* To examine whether early nurse contacts influenced self-reported measures of back pain and returns to work. PRIMARY PRACTICE SETTING(S): Workers with low back pain resulting in workers' compensation claims. METHODOLOGY AND SAMPLE: To quantify the influence of nurse case management on workers' satisfaction with their treatment by the firm and their healthcare provider, as well return to work, we follow 747 Marriott workers with incident episodes of low back pain in a prospective analysis. Predictors of outcomes include demographics, injury severity, and the timing of nurse case manager and work supervisor contacts. RESULTS: While early contacts do not have much impact on satisfaction with the treatment by the healthcare provider, early nurse case management contacts improve worker satisfaction with the firm's treatment of their claim, increasing satisfaction by 0.5 standard deviations (on a 4-point scale). The change in odds ratio with respect to a contact during the first week after injury is 8, indicating a 50-percentage point increase in the likelihood of continual employment. IMPLICATIONS FOR CM PRACTICE: *Among workers with low back pain, early nurse case management contacts improved workers' satisfaction with their healthcare provider and their treatment by the firm.* Contacts made during the first week after the injury were most valuable, but in our sample it did not matter when during that first week the contact was made (as long as it was within the first week).* Early nurse case management contacts substantially improved the odds of continual employment, dominating the influence of age, job satisfaction, and the expectation of a good recovery.

    Title Self-reported Severity Measures As Predictors of Return-to-work Outcomes in Occupational Back Pain.
    Date January 2008
    Journal Journal of Occupational Rehabilitation
    Excerpt

    INTRODUCTION: We test an array of biopsychosocial, cognitive-behavioral, and work-related factors to identify the best predictors of work disability following a back injury. METHODS: We test the validity of alternative severity measures in predicting the likelihood of four distinct, mutually exclusive patterns of post-injury employment in the first year after onset of back pain. The study sample includes 959 participants in the ASU Healthy Back Study, a prospective cohort study of workers who filed claims for occupational back pain between 1999 and 2002. Self-reported severity measures include: NRS-101 measures of the intensity of back or leg pain, Roland-Morris scale of functional disability, and mental and physical components of the SF-12. RESULTS: All the severity measures have significant predictive power on return-to-work outcomes even after 1 year. Baseline physical functioning and overall mental and physical health status are more predictive of specific patterns of post-injury employment than pain intensity measures, possibly because there is considerable idiosyncratic variation in the pain intensity measures. The mental component of the SF-12, in particular, is relatively robust to alternate specifications, consistently statistically significant, and has the lowest probability significance level in explaining patterns of employment 1 year after injury.

    Title A Primitive Ornithischian Dinosaur from the Late Triassic of South Africa, and the Early Evolution and Diversification of Ornithischia.
    Date October 2007
    Journal Proceedings. Biological Sciences / The Royal Society
    Excerpt

    Although the group played an important role in the evolution of Late Mesozoic terrestrial ecosystems, the early evolutionary history of the ornithischian dinosaurs remains poorly understood. Here, we report on a new primitive ornithischian, Eocursor parvus gen. et sp. nov. from the Late Triassic (?Norian) Lower Elliot Formation of South Africa. Eocursor is known from a single specimen comprising substantial cranial and postcranial material and represents the most complete Triassic member of Ornithischia, providing the earliest evidence for the acquisition of many key ornithischian postcranial characters, including an opisthopubic pelvis. A new phylogenetic analysis positions this taxon near the base of Ornithischia, as the sister taxon to the important and diverse clade Genasauria. The problematic clade Heterodontosauridae is also positioned basal to Genasauria, suggesting that an enlarged grasping manus may represent a plesiomorphic ornithischian condition. This analysis provides additional phylogenetic support for limited ornithischian diversity during the Late Triassic, and suggests that several major ornithischian clades may have originated later than generally believed. There are few morphological differences between Late Triassic and Early Jurassic ornithischians, supporting previous suggestions that the Early Jurassic ornithischian radiation may simply represent the filling of vacant ecological space following Late Triassic terrestrial extinctions.

    Title The Effect of a Subject-specific Amount of Lateral Wedge on Knee Mechanics in Patients with Medial Knee Osteoarthritis.
    Date September 2007
    Journal Journal of Orthopaedic Research : Official Publication of the Orthopaedic Research Society
    Excerpt

    We examined if a subject-specific amount of lateral wedge added to a foot orthosis could alter knee mechanics to potentially reduce the progression of knee osteoarthritis in patients with medial knee osteoarthritis. Twenty individuals with medial knee osteoarthritis (>/=2 Kellgren Lawrence grade) were prescribed a custom laterally wedged foot orthotic device. The prescribed wedge amount was the minimal wedge amount that provided the maximum amount of pain reduction during a lateral step-down test. Following an accommodation period, all subjects returned to the laboratory for a gait analysis. Knee mechanics were collected as the subjects walked at an intentional walking speed. Walking in the laterally wedged orthotic device significantly reduced the peak adduction moment during early stance (p < 0.01) compared to the nonwedged device. Similarly, the wedged orthotic device significantly reduced the knee adduction excursion from heel strike to peak adduction (p < 0.01) compared to the nonwedged device. No differences in the peak adduction moment during propulsion or peak adduction during stance were observed between the orthotic conditions. A subject-specific laterally wedged orthotic device was able to reduce the peak knee adduction moment during early stance, which is thought to be associated with the progression of knee osteoarthritis. Previous studies on this device have reported issues associated with foot discomfort when using wedge amounts >7 degrees; however, no such issues were reported in this study. Therefore, providing a custom laterally wedged orthotic device may potentially increase compliance while still potentially reducing disease progression.

    Title Impact of Medicaid Disenrollment on Health Care Use and Cost.
    Date May 2007
    Journal Pediatrics
    Excerpt

    OBJECTIVE: The objective of this study was to compare the health care use of children who are covered by public insurance and uninsured children who live in a large urban area and the potential impact of disenrollment on health care use and costs if these children become uninsured. METHODS: The 2004 health care transactions for 43,313 uninsured children and 168,722 children who were insured by Medicaid/State Children's Health Insurance Program and living in the Phoenix metropolitan area were analyzed using a community-wide administrative health database (Arizona HealthQuery). Using a multivariate model of health care use by currently uninsured children, we examined the effect of 10% disenrollment of the children who were currently insured by Medicaid/State Children's Health Insurance Program. RESULTS: A 10% disenrollment would increase the costs of health care in the community by $3,460,398 annually, or $2121 for each child disenrolled. This increase in costs is attributed to a shift of care from ambulatory settings to more expensive emergency departments and an increase in hospital days. We determined that 69% of the change in emergency department visits, 58% of the change in hospital stays, and 74% of the change in ambulatory visits would be attributable to the change in insurance status. CONCLUSIONS: Programmatic changes that result in disenrollment from public insurance programs will increase the number of emergency department visits and hospital days as well as the total community costs of health care. These increases in health care use can be expected to aggravate community problems of emergency department overcrowding and inpatient bed shortages. The majority of the changes in use are attributable to changes in insurance status, which results in a shift of care from less expensive ambulatory settings to emergency departments and increases in hospital days when children lose Medicaid/State Children's Health Insurance Program coverage.

    Title It Pays to Be Nice: Employer-worker Relationships and the Management of Back Pain Claims.
    Date March 2007
    Journal Journal of Occupational and Environmental Medicine / American College of Occupational and Environmental Medicine
    Excerpt

    OBJECTIVE: To quantify the influence that workers' satisfaction with the firm's treatment of their disability claim and their health care provider has on workers' return to work (RTW) following onset of occupational LBP. METHODS: Using a prospective survey on back pain, medical treatment, and workers' satisfaction, we employ nonparametric and logistic analyses to see how satisfaction affects RTW. RESULTS: Workers' satisfaction with their employer's treatment of their disability claim is more important in explaining RTW than satisfaction with health care providers or expectations about recovery. Dissatisfied workers have worse return to work outcomes because they are more likely to have time lost claims and are more likely to have multiple spells of joblessness. CONCLUSIONS: Workers' RTW is more responsive to their satisfaction with how the firm treated their disability claim than with their satisfaction with the health care provider. Satisfaction of both types plays an important role in determining RTW.

    Title Enuresis Alarm Treatment.
    Date February 2006
    Journal Scandinavian Journal of Urology and Nephrology
    Excerpt

    Treatment for childhood nocturnal enuresis emphasizes either a psychological or pharmacological approach. The enuresis alarm, in comparative studies, has emerged as the most effective psychological treatment. In this review we investigate both outcome rates and influential factors from recently published studies.

    Title Nocturnal Enuresis at 7.5 Years Old: Prevalence and Analysis of Clinical Signs.
    Date September 2005
    Journal Bju International
    Excerpt

    To determine the prevalence of nocturnal enuresis (NE) in a large cohort of children at 7.5 years old, and to examine the frequency of variables such as gender, severity, associated elimination problems, and clinical signs within the identified group.

    Title Quality Assurance and Meat Inspection in Australia.
    Date July 2005
    Journal Revue Scientifique Et Technique (international Office of Epizootics)
    Excerpt

    The aim of meat inspection in Australia is to contribute to the production of safe and wholesome food, comply with the requirements of importing countries, and support national animal health objectives. An analysis of the role of quality assurance (QA) in the meat inspection systems at federally inspected establishments shows that the position of Australia as a leading meat exporter is aided by a co-regulatory, QA-based approach to meat inspection, which is equally applicable to all species at slaughter. Technical developments in meat inspection at the national and international level during the 1990s led to significant enhancements in QA systems. Quality assurance is implemented through nationally uniform documented systems, which are designed to achieve consistent standards of meat safety. These systems are complemented by hazard analysis critical control point-based QA programmes which meet the quality-standards of the International Organization for Standardization. Quality assurance programmes aim for a 'whole of chain' approach, so that the system is implemented 'from the paddock to the plate', or from pre-harvest through to post-harvest, i.e., from on-farm practices to the refrigeration, storage and transportation stages. The QA elements of meat inspection employed in production systems in Australia have significantly contributed to the consistent achievement of meat safety objectives that are appropriate to contemporary risks.

    Title Sulfur-based Protecting Groups for Pyrroles and the Facile Deprotection of 2-(2,4-dinitrobenzene)sulfinyl and Sulfonyl Pyrroles.
    Date May 2005
    Journal The Journal of Organic Chemistry
    Excerpt

    [reaction: see text] The effectiveness of simple sulfinyl and sulfonyl groups as electron-withdrawing protecting groups for pyrroles has been analyzed using (13)C NMR spectroscopy and confirmed by consideration of X-ray crystal structures. Additionally, the 2,4-dinitrobenzenesulfinyl and sulfonyl groups are shown to be effective electron-withdrawing protecting groups for pyrroles, and they can be removed by treatment with benzene thiol or thiolate under mild and specific conditions.

    Title Childhood Nocturnal Enuresis: Developing a Conceptual Framework.
    Date March 2005
    Journal Clinical Psychology Review
    Excerpt

    Nocturnal enuresis has been described as the most prevalent and chronic of all childhood problems. The experience, particularly for the older child, can be extremely distressing and limiting. It is now thought that psychological distress (emotional, behavioural, and self-esteem) arises as a consequence of bedwetting, and reaches clinical importance in only a minority who are vulnerable. Many aetiological theories have been proposed with the cause of nocturnal enuresis now regarded as heterogeneous. Based on empirical findings, a new model, termed 'the three systems,' has facilitated a greater clinical understanding of the problem and identification of the appropriate intervention. The model proposes bedwetting results from excessive nocturnal urine production and/or nocturnal bladder overactivity coupled with an inability to arouse to bladder sensations. Effective treatment arises from identification of the child's particular need and application of the appropriate psychological and pharmacological approach. Treatment methods are reviewed in terms of the new model, the mode of action, effectiveness, and application in combination.

    Title An Exploration of Outcome Criteria in Nocturnal Enuresis Treatment.
    Date November 2004
    Journal Scandinavian Journal of Urology and Nephrology
    Excerpt

    This paper is a review of outcome definitions and criteria for nocturnal enuresis treatment. A search of the literature published between 1991 and 2001 highlighted 97 papers. Although the International Children's Continence Society and the World Health Organization have published outcome criteria, different, often idiosyncratic, outcome criteria and/or definitions have been adopted in published research on treatment for nocturnal enuresis in recent years. There remains a debate as to what constitutes successful treatment and how to document improvement. Lack of an agreed definition of outcome reduces confidence in comparing studies, with serious clinical and research implications. This paper reviews aspects of importance in determining outcome, including a suggestion to focus on the establishment of dry nights rather than the reduction of wet nights. A new set of criteria is suggested, consisting of a banding system referred to as a "dryness scale", which focuses on the percentage of dry nights accomplished at a point in time, thus eliminating the need to compare current levels of dryness with a baseline.

    Title Investigating the Three Systems Approach to Complex Childhood Nocturnal Enuresis--medical Treatment Interventions.
    Date August 2004
    Journal Scandinavian Journal of Urology and Nephrology
    Excerpt

    Nocturnal enuresis is a heterogeneous condition with various treatment options of both pharmacological and psychological origin. The three systems model previously proposed by us suggests a framework to facilitate understanding, identify a child's needs and specify the appropriate treatment option. In this study we sought to investigate the model in clinical practice in a group of children with severe nocturnal enuresis, with particular reference to pharmacological treatment.

    Title Self-construing in Children with Primary Mono-symptomatic Nocturnal Enuresis--an Investigation of Three Measures.
    Date March 2004
    Journal Scandinavian Journal of Urology and Nephrology
    Excerpt

    This study aims to measure different aspects of self-construing in children with primary mono-symptomatic nocturnal enuresis.

    Title Lower Extremity Stiffness: Implications for Performance and Injury.
    Date August 2003
    Journal Clinical Biomechanics (bristol, Avon)
    Excerpt

    Lower extremity stiffness is thought to be an important factor in musculoskeletal performance. However, too little or too much stiffness is believed to increase the risk of musculoskeletal injury.

    Title Alarm Treatment for Childhood Nocturnal Enuresis: an Investigation of Within-treatment Variables.
    Date November 2002
    Journal Scandinavian Journal of Urology and Nephrology
    Excerpt

    The enuresis alarm has been widely advocated as an effective intervention in the treatment of childhood nocturnal enuresis. Although there is a body of evidence concerning which pretreatment variables are related to outcome, there is little evidence relating to influential within-treatment variables. This study sought to examine a series of treatment variables against outcome.

    Title An Investigation of the Impact of Nocturnal Enuresis on Children's Self-concept.
    Date October 2002
    Journal Scandinavian Journal of Urology and Nephrology
    Excerpt

    OBJECTIVE: This study sought to evaluate the relationship between the self-esteem and the self-image of children with nocturnal enuresis and to examine these in relation to various aspects of clinical and demographic variables. Previous studies investigating the self-esteem of bedwetting children have had mixed findings. Some studies report that children with nocturnal enuresis have a lower self-esteem than their non-bedwetting peers, but other studies report that children with nocturnal enuresis perceive themselves similarly to non-bedwetting children. However, what have not been studied to date are the self-perceptions of bedwetting children treated in community clinics. MATERIAL AND METHODS: A total of 114 bedwetting children treated in community clinics provided the sample. School nurses conducted a routine first-visit assessment, collected baseline demographic and social information and invited children to complete the Butler Self-Image Profile and the Coopersmith Self-Esteem Inventory. RESULTS: Age and extent of wetting were not significantly related to self-concept measures. Girls had significantly (p = 0.008) higher scores on positive self-image compared with boys. Children with secondary enuresis also scored higher on positive self-image compared with those with primary nocturnal enuresis (p = 0.02). The Butler self-image scores indicated a number of significant links between positive self-image and enuresis variables, whereas the Coopersmith self-esteem scores generally failed to distinguish between the enuresis variables and closely reflected those of the negative self-image scores. CONCLUSIONS: These findings suggest that amongst children with nocturnal enuresis, the most vulnerable in terms of self-image are male, those with primary enuresis and those with a greater number of wet nights a week.

    Title Waiting Periods and Health-related Absenteeism: the Need for Program Integration.
    Date September 2001
    Journal Benefits Quarterly
    Excerpt

    This article discusses evidence that the reduction of waiting period deductibles in disability insurance plans increases the amount of lost time utilized by insured workers and also increases the cost of sick leave. The authors posit that the evidence supports the need for an integrated disability insurance product, which could be offered at lower costs than the current system that provides fragmented lost time coverage.

    Title The Three Systems: a Conceptual Way of Understanding Nocturnal Enuresis.
    Date May 2001
    Journal Scandinavian Journal of Urology and Nephrology
    Excerpt

    Childhood nocturnal enuresis has traditionally been regarded as a multifaceted problem with a variety of treatment interventions. This paper proposes a model based on the notion that nocturnal enuresis arises through the ill functioning of one or more of the following three systems - a lack of vasopressin release during sleep; bladder instability; and/or an inability to arouse from sleep to bladder sensations. Clinical signs of each system are outlined and the appropriate treatment intervention for each is discussed. It is argued that addressing nocturnal enuresis in this way will enhance overall treatment effectiveness.

    Title Healthcare Provider-sponsored Virtual Communities: the Benefits of the Electronic Village.
    Date August 2000
    Journal Journal of Healthcare Information Management : Jhim
    Title Benefits Management Beyond the Adding Machine: Using Integrated, Worker-specific Analysis.
    Date January 2000
    Journal Benefits Quarterly
    Excerpt

    Modern employee benefits practices have not taken advantage of modern information technology largely because of an implicit reliance on "adding machine" approaches to health care benefits. This article argues that an integrated, worker-specific approach to benefits management is needed in a modern benefits environment. Quantitative illustrations of the integrated approach are provided in terms of a benefits Pareto analysis. The empirical results presented suggest that human resource/risk management practices can have a significant impact on worker benefits costs.

    Title Coordinate Expression of the Autosomal Dominant Polycystic Kidney Disease Proteins, Polycystin-2 and Polycystin-1, in Normal and Cystic Tissue.
    Date July 1999
    Journal The American Journal of Pathology
    Excerpt

    A second gene for autosomal dominant polycystic kidney disease (ADPKD), PKD2, has been recently identified. Using antisera raised to the human PKD2 protein, polycystin-2, we describe for the first time its distribution in human fetal tissues, as well as its expression in adult kidney and polycystic PKD2 tissues. Its expression pattern is correlated with that of the PKD1 protein, polycystin-1. In normal kidney, expression of polycystin-2 strikingly parallels that of polycystin-1, with prominent expression by maturing proximal and distal tubules during development, but with a more pronounced distal pattern in adult life. In nonrenal tissues expression of both polycystin molecules is identical and especially notable in the developing epithelial structures of the pancreas, liver, lung, bowel, brain, reproductive organs, placenta, and thymus. Of interest, nonepithelial cell types such as vascular smooth muscle, skeletal muscle, myocardial cells, and neurons also express both proteins. In PKD2 cystic kidney and liver, we find polycystin-2 expression in the majority of cysts, although a significant minority are negative, a pattern mirrored by the PKD1 protein. The continued expression of polycystin-2 in PKD2 cysts is similar to that seen by polycystin-1 in PKD1 cysts, but contrasts with the reported absence of polycystin-2 expression in the renal cysts of Pkd2+/- mice. These results suggest that if a two-hit mechanism is required for cyst formation in PKD2 there is a high rate of somatic missense mutation. The coordinate presence or loss of both polycystin molecules in the same cysts supports previous experimental evidence that heterotypic interactions may stabilize these proteins.

    Title Evidence for Linkage to Psychosis and Cerebral Asymmetry (relative Hand Skill) on the X Chromosome.
    Date December 1998
    Journal American Journal of Medical Genetics
    Excerpt

    The hypothesis that psychosis arises as a part of the genetic diversity associated with the evolution of language generates the prediction that illness will be linked to a gene determining cerebral asymmetry, which, from the evidence of sex chromosome aneuploidies, is present in homologous form on the X and Y chromosomes. We investigated evidence of linkage to markers on the X chromosome in 1) 178 families multiply affected with schizophrenia or schizoaffective disorder with a series of 16 markers spanning the centromere (study 1), and 2) 180 pairs of left-handed brothers with 14 markers spanning the whole chromosome (study 2). In study 1, excess allele-sharing was observed in brother-brother pairs (but not brother-sister or a small sample of sister-sister pairs) over a region of approximately 20 cM, with a maximum LOD score of 1.5 at DXS991. In study 2, an association between allele-sharing and degree of left-handedness was observed extending over approximately 60 cM, with a maximum lod score of 2.8 at DXS990 (approximately 20 cM from DXS991). Within the overlap of allele-sharing is located a block in Xq21 that transposed to the Y chromosome in recent hominid evolution and is now represented as two segments on Yp. In one of two XX males with psychosis we found that the breakpoint on the Y is located within the distal region of homology to the block in Xq21. These findings are consistent with the hypothesis that an X-Y homologous determinant of cerebral asymmetry carries the variation that contributes to the predisposition to psychotic illness.

    Title Annotation: Night Wetting in Children: Psychological Aspects.
    Date August 1998
    Journal Journal of Child Psychology and Psychiatry, and Allied Disciplines
    Title Public Health Hazards of Meat from Small Ruminants: the Perspective of Australia.
    Date June 1998
    Journal Revue Scientifique Et Technique (international Office of Epizootics)
    Excerpt

    The production of meat from sheep and goats in Australia occurs almost entirely at pasture in zones known as the semi-arid pastoral zone, the wheat-sheep zone (where sheep and crops form an agricultural rotation system) and the high rainfall zone. Each zone has particular factors which affect the human health hazards associated with sheep and goat meat and the opportunities for prevention. The authors provide an overview of small ruminant production in Australia and a synopsis of the diseases encountered, including the factors which influence epidemiology. Animal health arrangements for underwriting food safety at the pre-harvest and post-harvest stages of production in Australia are also outlined. Specific public health hazards related to sheep and goat meat, together with measures for prevention, are considered under the headings of zoonoses, enteropathogens and chemical residues.

    Title Hmos, Moral Hazard and Cost Shifting in Workers' Compensation.
    Date September 1997
    Journal Journal of Health Economics
    Excerpt

    Previous research has shown that workers respond to the economic incentives provided in workers' compensation. In particular, claim frequency rises with increased benefits, and claim duration, on net, seems to increase. Here we provide additional evidence of another incidence of behavioral responses to incentives. We find that doctors in health maintenance organizations (HMOs) have a greater tendency to classify claims as compensable under workers' compensation than do other physicians. Our evidence suggests that the rapid expansion of HMOs over the 1980-1990 period resulted in a significant increase in workers' compensation claim frequency.

    Title The Error of Using Returns-to-work to Measure the Outcomes of Health Care.
    Date November 1996
    Journal American Journal of Industrial Medicine
    Excerpt

    This article uses data from The Survey of Ontario Workers With Permanent Impairments. the world's largest survey of injured workers, to show that, as currently used, return-to-work is a misleading measure of the effectiveness of health care. The article discusses examples of two serious limitations on the use of return-to-work to measure the outcomes of health care, where health care refers to all the medical and rehabilitative services provided to a worker following a workplace injury. The first limitation is that return-to-work, like many other outcomes of health care, is influenced by factors that are not directly related to health care. Using a logit model to estimate the determinants of first absences from work after an injury, we find that socioeconomic characteristics, economic incentives, and job characteristics have a significant influence on return-to-work. The second limitation on return-to-work as an outcome measure is that the first return-to-work after an injury, like a hospital discharge, frequently marks the end of only the first of several episodes of work disability caused by the original injury. Using first post-injury returns-to-work as a proxy for recovery, we would assume that 85% of the Ontario workers recovered from their injury when, in fact, 61% had subsequent spells of work disability. We identified four mutually exclusive patterns of post-injury work and work disability. Multinomial logit estimates of the determinants of the patterns show that health care is only one of several influences on return-to-work. The results also demonstrate that if return-to-work is used to measure outcomes, it must be evaluated over a time horizon that permits multiple spells of work disability.

    Title The Genomic Structure of Discoidin Receptor Tyrosine Kinase.
    Date October 1996
    Journal Genome Research
    Excerpt

    The discoidin domain receptor (DDR) is a new class of receptor tyrosine kinase that is distinguished by a unique extracellular domain homologous to the lectin Discoidin I found Dictyostelium discoideum. A cosmid was isolated from a human chromosome 6 cosmid library containing the DDR gene. A complete genomic contig of the DDR gene was constructed from seven subclones of the cosmid. The cosmid fragments were analyzed by PCR, sequencing, and comparison of genomic/cDNA sequence. The DDR gene is composed of 17 exons, ranging in size from 96 to 1014 bp, distributed along approximately 12 kb of genomic DNA. The extracellular domain is encoded by 8 exons of which three code for the discoidin domain. The transmembrane domain is encoded by 1 exon, the juxtamembrane by 3 exons, and the catalytic domain by 5 exons. The generation of the two splice variants of DDR, EDDR1 and EDDR2 are explained by the genomic structure. Exon 11 (111 bp in the juxtamembrane domain) is present in DDR and absent in the splice variant EDDR1. An inverted repeat of 20 bp was identified at the 3' exon-intron junction of exon 11, which results in a lariat loop-like secondary structure. EDDR2 is generated because of a cryptic splice acceptor site that results in an extra 18 bp (6 amino acids) inserted 5' of exon 14 in the catalytic domain. A polymorphic (GT)17 repeat was identified in intron 5 with a heterozygosity of 0.71. The exon-intron structure of the DDR gene will be helpful in further understanding of its function and explains the possible structural basis for the two splice variants.

    Title Multivessel Supercritical Fluid Extraction of Food Items in Total Diet Study.
    Date November 1995
    Journal Journal of Aoac International
    Excerpt

    An off-line, large capacity, multivessel supercritical fluid extractor (SFE) was designed and constructed for extraction of large samples. The extractor can simultaneously process 1-6 samples (15-25 g) by using supercritical carbon dioxide (SC-CO2), which is relatively nontoxic and nonflammable, as the solvent extraction medium. Lipid recoveries for the SFE system were comparable to those obtained by blending or Soxhlet extraction procedures. Extractions at 10,000 psi, 80 degrees C, expanded gaseous CO2 flow rates of 4-5 L/min (35 degrees C), and 1-3 h extraction times gave reproducible lipid recoveries for pork sausage (relative standard deviation [RSD], 1.32%), corn chips (RSD, 0.46%), cheddar cheese (RSD, 1.14%), and peanut butter (RSD, 0.44%). In addition, this SFE system gave reproducible recoveries (> 93%) for butter fortified with cis-chlordane and malathion at the 100 ppm and 0.1 ppm levels. Six portions each of cheddar cheese, saltine crackers, sandwich cookies, and ground hamburger also were simultaneously extracted with SC-CO2 and analyzed for incurred pesticide residues. Results obtained with this SFE system were reproducible and comparable with results from organic-solvent extraction procedures currently used in the Total Diet Study; therefore, use and disposal of large quantities of organic solvents can be eliminated.

    Title Hiv Exposure in Health Care.
    Date August 1995
    Journal The Medical Journal of Australia
    Title Neuropsychological Investigation of Amateur Boxers.
    Date January 1995
    Journal British Journal of Sports Medicine
    Excerpt

    Amateur boxing is faced with criticism over the potential damage the sport inflicts on those who participate. The most sensitive measure of early neurological dysfunction is neuropsychological investigation. Ten studies employing such assessments on 289 amateur boxers are reviewed. The forms of analysis undertaken include controlled comparison with other sportsmen, of both active and former boxers, detailed pre- and post-bout analysis, analysis of the influence of within-boxing variables, length of career, level of competition and prospective longitudinal investigation. Amateur boxers were found to exhibit no signs of neuropsychological dysfunction in any analysis. However some trends emerged suggesting a long career in amateur boxing might reduce fine motor reactions, although such findings are within the normal range and do not represent central neuropsychological functioning. Thus amateur boxing does not appear to expose individuals to neurological dysfunction.

    Title A Prospective Controlled Investigation of the Cognitive Effects of Amateur Boxing.
    Date November 1993
    Journal Journal of Neurology, Neurosurgery, and Psychiatry
    Excerpt

    Eighty six amateur boxers underwent a series of neuropsychological assessments on three occasions--pre bout, immediate post bout and follow up within two years; 31 water polo players and 47 rugby union players acted as controls. The neuropsychological tests were selected as being sensitive to subtle cognitive dysfunction and formed part of a battery of other neurological and ophthalmic assessments. No evidence of neuropsychological dysfunction due to boxing was found, either following a bout or a series of bouts at follow up. None of a range of parameters including number of previous contests, recovery from an earlier bout, number of head blows received during a bout and number of bouts between initial assessment and follow up, were found to be related to changes in cognitive functioning.

    Title Establishing a Dry Run: a Case Study in Securing Bladder Control.
    Date August 1993
    Journal The British Journal of Clinical Psychology / the British Psychological Society
    Excerpt

    Relapse following treatment with an enuresis alarm is not uncommon with nocturnal enuresis (Bollard, 1982). This paper illustrates how one boy struggled to reduce dependence on the alarm and how visualization finally provided the means whereby awareness of bladder signals was achieved.

    Title Establishment of Working Definitions in Nocturnal Enuresis.
    Date April 1991
    Journal Archives of Disease in Childhood
    Title Radiological Artefact.
    Date April 1991
    Journal Australian Dental Journal
    Title The Child's Construing of Nocturnal Enuresis: a Method of Inquiry and Prediction of Outcome.
    Date May 1990
    Journal Journal of Child Psychology and Psychiatry, and Allied Disciplines
    Excerpt

    Fifty-five children with nocturnal enuresis were engaged in a structured interview prior to treatment with the body-worn alarm. The interview sought to understand how children make sense of the experience and examines the implications for becoming dry. Successful treatment outcome was found to be associated with the child both construing bedwetting psychologically, and indicating no resistance to change. The importance of establishing the child's attitude to bedwetting prior to treatment is stressed.

    Title Fifty Years of Enuretic Alarms.
    Date September 1989
    Journal Archives of Disease in Childhood
    Title A Comparison of Two Approaches to the Treatment of Nocturnal Enuresis and the Prediction of Effectiveness Using Pre-treatment Variables.
    Date February 1989
    Journal Journal of Child Psychology and Psychiatry, and Allied Disciplines
    Excerpt

    This study compared the effectiveness of the enuresis alarm alone with a brief version of Dry Bed Training in treating 74 enuretic children. Both procedures were equally effective, and in the total sample a better response to treatment was predicted by the child's report of being teased by siblings. Maternal anger was associated with a greater drop-out rate.

    Title Maternal Attributions and Tolerance for Nocturnal Enuresis.
    Date August 1986
    Journal Behaviour Research and Therapy
    Title Quality Assurance in Hospital Dental Practice.
    Date February 1985
    Journal Australian Dental Journal
    Title An Analysis of Individual Treatment on a Token Economy for Chronic Schizophrenic Patients.
    Date December 1979
    Journal The British Journal of Medical Psychology
    Excerpt

    Fifty-one individually designed treatment programmes carried out over a 22 month period on a token economy ward for 12 female chronic schizophrenic patients were analysed. Level of withdrawal was found to be a critical factor in patients' response, both in terms of the rate and extent of improvement during the treatment stage, and presence or absence of deterioration during 'weaning' and follow up. No difference in response between type of behavioural problem and methods of treatment or weaning were found.

    Title Adjusting Rehabilitation Costs and Benefits for Health Capital: the Case of Low Back Occupational Injuries.
    Date
    Journal Journal of Occupational Rehabilitation
    Excerpt

    Case-mix adjustments for treatment/rehabilitation costs and benefits of non-traumatic injuries, such as occupational back pain, are much more difficult than adjustments for traumatic injuries. We present a new method for adjusting for severity differences in the costs and benefits of treating occupational low back injuries.

    Title A Modified Measure of Health Care Disparities Applied to Birth Weight Disparities and Subsequent Mortality.
    Date
    Journal Health Economics
    Excerpt

    We describe how a modified Gini index serves as an improved method of estimating health care disparities. The method, although general, is applied to an example of birth weight disparities and to their effect on subsequent mortality. The method provides the between-group results obtainable from current methods (i.e. how Hispanics generally fare relative to non-Hispanic Whites) but adds measures of within-group disparities (i.e. which specific Hispanics experience the greatest disparate treatment). Our application to birth weights and receipt of prenatal care, which may provide an upper bound because of omitted variables, shows that the time-of-birth disparities are associated with increased infant mortality within the first year of life. Copyright © 2010 John Wiley & Sons, Ltd.

    Title Air-filled Postcranial Bones in Theropod Dinosaurs: Physiological Implications and the 'reptile'-bird Transition.
    Date
    Journal Biological Reviews of the Cambridge Philosophical Society
    Excerpt

    Pneumatic (air-filled) postcranial bones are unique to birds among extant tetrapods. Unambiguous skeletal correlates of postcranial pneumaticity first appeared in the Late Triassic (approximately 210 million years ago), when they evolved independently in several groups of bird-line archosaurs (ornithodirans). These include the theropod dinosaurs (of which birds are extant representatives), the pterosaurs, and sauropodomorph dinosaurs. Postulated functions of skeletal pneumatisation include weight reduction in large-bodied or flying taxa, and density reduction resulting in energetic savings during foraging and locomotion. However, the influence of these hypotheses on the early evolution of pneumaticity has not been studied in detail previously. We review recent work on the significance of pneumaticity for understanding the biology of extinct ornithodirans, and present detailed new data on the proportion of the skeleton that was pneumatised in 131 non-avian theropods and Archaeopteryx. This includes all taxa known from significant postcranial remains. Pneumaticity of the cervical and anterior dorsal vertebrae occurred early in theropod evolution. This 'common pattern' was conserved on the line leading to birds, and is likely present in Archaeopteryx. Increases in skeletal pneumaticity occurred independently in as many as 12 lineages, highlighting a remarkably high number of parallel acquisitions of a bird-like feature among non-avian theropods. Using a quantitative comparative framework, we show that evolutionary increases in skeletal pneumaticity are significantly concentrated in lineages with large body size, suggesting that mass reduction in response to gravitational constraints at large body sizes influenced the early evolution of pneumaticity. However, the body size threshold for extensive pneumatisation is lower in theropod lineages more closely related to birds (maniraptorans). Thus, relaxation of the relationship between body size and pneumatisation preceded the origin of birds and cannot be explained as an adaptation for flight. We hypothesise that skeletal density modulation in small, non-volant, maniraptorans resulted in energetic savings as part of a multi-system response to increased metabolic demands. Acquisition of extensive postcranial pneumaticity in small-bodied maniraptorans may indicate avian-like high-performance endothermy.

    Similar doctors nearby

    Dr. Merla Puray

    Internal Medicine
    16 years experience
    Merced, CA

    Dr. Henry Lam

    Internal Medicine
    28 years experience
    Merced, CA

    Dr. Imtiaz Malik

    Internal Medicine
    33 years experience
    Merced, CA

    Dr. Nicolas Delapena

    Internal Medicine
    24 years experience
    Merced, CA

    Dr. James Reid

    Internal Medicine
    40 years experience
    Merced, CA

    Dr. Lekshmi Vallyathan

    Internal Medicine
    8 years experience
    Merced, CA
    Search All Similar Doctors