bluuebunny/crossref_metadata_2025 huggingface dataset:
The Boomers Are Coming: A Total Cost of Care Model of the Impact of Population Aging on Health Care Costs in the United States by Major Practice Category
Authors: Mary Martini E. , Garrett Nancy , Lindquist Tammie , Isham George J.
Published: August 2006

Objective. To project the impact of population aging on total U.S. health care per capita costs from 2000 to 2050 and for the range of clinical areas defined by Major Practice Categories (MPCs).

Data Sources. Secondary data: HealthPartners health plan administrative data; U.S. Census Bureau population projections 2000–2050; and MEPS 2001 health care annual per capita costs.

Study Design. We calculate MPC‐specific age and gender per capita cost rates using cross‐sectional data for 2002–2003 and project U.S. changes by MPC due to aging from 2000 to 2050.

Data Collection Methods. HealthPartners data were grouped using purchased software. We developed and validated a method to include pharmacy costs for the uncovered.

Principal Findings. While total U.S. per capita costs due to aging from 2000 to 2050 are projected to increase 18 percent (0.3 percent annually), the impact by MPC ranges from a 55 percent increase in kidney disorders to a 12 percent decrease in pregnancy and infertility care. Over 80 percent of the increase in total per capita cost will result from just seven of the 22 total MPCs.

Conclusions. Understanding the differential impact of aging on costs at clinically specific levels is important for resource planning, to effectively address future medical needs of the aging U.S. population.
Use of Aggressive Medical Treatments Near the End of Life: Differences between Patients with and without Dementia
Authors: Richardson Samuel S. , Sullivan Greer , Hill Ariel , Yu Wei
Published: August 2006

Objective. To analyze whether acute care patients with dementia are more or less likely to receive each of five aggressive medical services near the end of life, compared with patients without dementia.

Data Sources. Two years of Veterans Affairs (VA) and Medicare utilization data for all 169,036 VA users nationwide age 67 and older who died between October 1, 1999 and September 30, 2001.

Study Design. We performed a retrospective analysis of acute care stays discharged in the final 30 days of life. The main outcome measure was the patient's likelihood of receiving each of five aggressive services (intensive care unit [ICU] admission, ventilator, cardiac catheterization, pulmonary artery monitor, and dialysis), controlling for demographic and clinical factors in probit regressions.

Principal Findings. There were 122,740 acute‐stay discharges during the final 30 days of life, representing 94,100 unique patients (31,654 with dementia). In probit models comparing acute care patients with and without dementia, patients with dementia were 7.5 percentage points less likely to be admitted to the ICU (95 percent confidence interval [CI], 6.9–8.1; percent of stays with ICU admission=36.8 percent), 5.4 percentage points less likely to be placed on a ventilator (95 percent CI, 5.0–5.9; percent of stays with ventilator use=17.1 percent), 0.7 percentage points less likely to receive cardiac catheterization (95 percent CI, 0.6–0.8; percent of stays with cardiac catheterization=2.7 percent), 1.4 percentage points less likely to receive pulmonary artery monitoring (95 percent CI, 1.2–1.5; percent of stays with pulmonary artery monitoring=2.6 percent), and 0.6 percentage points less likely to receive dialysis (95 percent CI, 0.4–0.8; percent of stays with dialysis=4.6 percent).

Conclusions. During the final 30 days of life, acute care patients with dementia are treated substantially less aggressively than patients without dementia. Further research is warranted to determine the causes and appropriateness of these patterns of care.
Racial Disparities in Completion Rates from Publicly Funded Alcohol Treatment: Economic Resources Explain More Than Demographics and Addiction Severity
Authors: Jacobson Jerry O. , Robinson Paul L. , Bluthenthal Ricky N.
Published: August 2006

Objectives. To assess racial and ethnic differences in rates of completion from publicly funded alcohol treatment programs, and to estimate the extent to which any identified racial differences in completion rates are related to differences in patient characteristics.

Data Sources. Administrative intake and discharge records from all publicly funded outpatient and residential alcohol treatment recovery programs in Los Angeles County (LAC) during 1998–2000. Study participants (N=10,591) are African American, Hispanic, and white patients discharged from these programs, ages 18 or older, who reported alcohol as their primary substance abuse problem.

Study Design. Bivariate tests identified racial and ethnic differences in rates of treatment completion and patient characteristics. Logistic regression models assessed the contribution of differences in patient characteristics to differences in completion.

Principal Findings. Significantly lower completion rates by African Americans (17.5 percent) relative to whites (26.7 percent) (odds ratio [OR]=0.58, 95 percent confidence interval [CI]: 0.50–0.68) are partially explained (40 percent) by differences in patient characteristics in outpatient care (adjusted OR=0.75, 95 percent CI: 0.63–0.90), mostly by indicators of economic resources (i.e., employment, homelessness, and Medi‐Cal beneficiary). In residential care, only 7 percent of differences in completion (30.7 versus 46.1 percent) could be explained by the patient‐level measures available (OR=0.52, 95 percent CI: 0.45–0.59; AOR=0.55, 95 percent CI: 0.47–0.65). Differences in completion rates between Hispanic and white patients were not detected.

Conclusions. Large differences in rates of outpatient and residential alcohol treatment completion between African American and white patients at publicly funded programs in LAC, the nation's second largest, publicly funded alcohol and drug treatment system, are partially because of economic differences among patients, but remain largely unexplained. These racial disparities merit additional investigation and the attention of health professionals.
Cancer Stage at Diagnosis and Survival among Persons with Social Security Disability Insurance on Medicare
Authors: McCarthy Ellen P. , Ngo Long H. , Chirikos Thomas N. , Roetzheim Richard G. , Li Donglin , Drews Reed E. , Iezzoni Lisa I.
Published: August 2006

Objective. To examine stage at diagnosis and survival for disabled Medicare beneficiaries diagnosed with cancer under age 65 and compare their experiences with those of other persons diagnosed under age 65.

Data Sources. Surveillance, Epidemiology, and End Results (SEER) Program data and SEER‐Medicare linked data for 1988–1999. SEER‐11 Program includes 11 population‐based tumor registries collecting information on all incident cancers in catchment areas. Tumor registry and Medicare data are linked for persons enrolled in Medicare.

Study Design. 307,595 incident cases of non‐small cell lung (51,963), colorectal (52,092), breast (142,281), and prostate (61,259) cancer diagnosed in persons under age 65 from 1988 to 1999. Persons who qualified for Social Security Disability Insurance and had Medicare (SSDI/Medicare) were identified from Medicare enrollment files. Ordinal polychotomous logistic regression and Cox proportional hazards regression were used to estimate adjusted associations between disability status and later‐stage diagnoses and mortality (all‐cause and cancer‐specific).

Principal Findings. Persons with SSDI/Medicare had lower rates of Stages III/IV diagnoses than others for lung (63.3 versus 69.5 percent) and prostate (25.5 versus 30.8 percent) cancers, but not for breast or colorectal cancers. After adjustment, they remained less likely to be diagnosed at later stages for lung and prostate cancers. Nevertheless, persons with SSDI/Medicare experienced higher all‐cause mortality for each cancer. Cancer‐specific mortality was higher among persons with SSDI/Medicare for breast and colorectal cancer patients.

Conclusions. Disabled Medicare beneficiaries are diagnosed with cancer at similar or earlier stages than others. However, they experience higher rates of cancer‐related mortality when diagnosed at the same stage of breast and colorectal cancer.
Women's Satisfaction with Their On‐Going Primary Health Care Services: A Consideration of Visit‐Specific and Period Assessments
Authors: Anderson Roger T. , Weisman Carol S. , Camacho Fabian , Scholle Sarah Hudson , Henderson Jillian T. , Farmer Deborah F.
Published: August 2006

Objective. To compare and contrast patient ratings of satisfaction with primary care on the day of visit versus over the last 12 months.

Data Sources/Study Setting. Survey data were collected from female participants at primary care centers affiliated with the University of Michigan, University of Pittsburgh, and Wake Forest University.

Study Design. One thousand and twenty‐one patients attending a primary care visit with at least one prior visit to the study site were consented on site, enrolled in the study, and surveyed at two time points: pre‐ and immediately postvisit.

Data Collection. The previsit survey included demographics, self‐rated health, visit history (site continuity), and expectations for health care; the postvisit survey focused on patient experiences during the visit, assessment of health care quality using the Primary Care Satisfaction Survey for Women instrument, and global satisfaction with visit and health care over the past 12 months. Expectation discrepancy scores were constructed from the linked expectation–experience ratings. Path analysis and indices of model fit were used to investigate the strength of theoretical links among the variables in an analytic model considering both day‐of‐visit and past‐year ratings with global measures of patient satisfaction as the dependent variables.

Principal Findings. General health, site continuity and fulfillment of patient expectations for care were linked to global ratings of satisfaction through effects on communication, care coordination, and office staff and administration. Importantly, past‐year ratings were mediated largely by care coordination and continuity; day‐of‐visit ratings were mediated by communication.

Conclusion. Ratings of health care quality for a specific visit appear to be conceptually distinct from ratings of care over the past 12 months, and thus are not interchangeable.
Defining Interdisciplinary Research: Conclusions from a Critical Review of the Literature
Authors: Aboelela Sally W. , Larson Elaine , Bakken Suzanne , Carrasquillo Olveen , Formicola Allan , Glied Sherry A. , Haas Janet , Gebbie Kristine M.
Published: August 2006

Objective.To summarize findings from a systematic exploration of existing literature and views regarding interdisciplinarity, to discuss themes and components of such work, and to propose a theoretically based definition of interdisciplinary research.

Data Sources/Study Setting.Two major data sources were used: interviews with researchers from various disciplines, and a systematic review of the education, business, and health care literature from January 1980 through January 2005.

Study Design.Systematic review of literature, one‐on‐one interviews, field test (survey).

Data Collection/Extraction Methods.We reviewed 14 definitions of interdisciplinarity, the characteristics of 42 interdisciplinary research publications from multiple fields of study, and 14 researcher interviews to arrive at a preliminary definition of interdisciplinary research. That definition was then field tested by 12 individuals with interdisciplinary research experience, and their responses incorporated into the definition of interdisciplinary research proposed in this paper.

Principal Findings.Three key definitional characteristics were identified: the qualitative mode of research (and its theoretical underpinnings), existence of a continuum of synthesis among disciplines, and the desired outcome of the interdisciplinary research.

Conclusion.Existing literature from several fields did not provide a definition for interdisciplinary research of sufficient specificity to facilitate activities such as identification of the competencies, structure, and resources needed for health care and health policy research. This analysis led to the proposed definition, which is designed to aid decision makers in funding agencies/program committees and researchers to identify and take full advantage the interdisciplinary approach, and to serve as a basis for competency‐based formalized training to provide researchers with interdisciplinary skills.
Comparing Self‐Reported Health Status and Diagnosis‐Based Risk Adjustment to Predict 1‐ and 2 to 5‐Year Mortality
Authors: Pietz Kenneth , Petersen Laura A.
Published: August 2006

Objectives. To compare the ability of two diagnosis‐based risk adjustment systems and health self‐report to predict short‐ and long‐term mortality.

Data Sources/Study Setting. Data were obtained from the Department of Veterans Affairs (VA) administrative databases. The study population was 78,164 VA beneficiaries at eight medical centers during fiscal year (FY) 1998, 35,337 of whom completed an 36‐Item Short Form Health Survey for veterans (SF‐36V) survey.

Study Design. We tested the ability of Diagnostic Cost Groups (DCGs), Adjusted Clinical Groups (ACGs), SF‐36V Physical Component score (PCS) and Mental Component Score (MCS), and eight SF‐36V scales to predict 1‐ and 2–5 year all‐cause mortality. The additional predictive value of adding PCS and MCS to ACGs and DCGs was also evaluated. Logistic regression models were compared using Akaike's information criterion, the c‐statistic, and the Hosmer–Lemeshow test.

Principal Findings. The c‐statistics for the eight scales combined with age and gender were 0.766 for 1‐year mortality and 0.771 for 2–5‐year mortality. For DCGs with age and gender the c‐statistics for 1‐ and 2–5‐year mortality were 0.778 and 0.771, respectively. Adding PCS and MCS to the DCG model increased the c‐statistics to 0.798 for 1‐year and 0.784 for 2–5‐year mortality.

Conclusions. The DCG model showed slightly better performance than the eight‐scale model in predicting 1‐year mortality, but the two models showed similar performance for 2–5‐year mortality. Health self‐report may add health risk information in addition to age, gender, and diagnosis for predicting longer‐term mortality.
Determinants of Children's Participation in California's Medicaid and SCHIP Programs
Authors: Kincheloe Jennifer , Frates Janice , Brown E. Richard
Published: August 2006

Objective. To develop a comprehensive predictive model of eligible children's enrollment in California's Medicaid (Medi‐Cal [MC]) and State Children's Health Insurance Program (SCHIP; Healthy Families [HF]) programs.

Data Sources/Study Setting. 2001 California Health Interview Survey data, data on outstationed eligibility workers (OEWs), and administrative data from state agencies and local health insurance expansion programs for fiscal year 2000–2001.

Study Design. The study examined the effects of multiple family‐level factors and contextual county‐level factors on children's enrollment in Medicaid and SCHIP.

Data Collection/Extraction Methods. Simple logistical regression analyses were conducted with sampling weights. Hierarchical logistic regressions were run to control for clustering.

Principal Findings. Participation in MC and HF programs is determined by a combination of family‐level predisposing, perceived need, and enabling/disabling factors, and county‐level enabling/disabling factors. The strongest predictors of MC enrollment were family‐level immigration status, ethnicity, and income, and the presence of a county‐level “expansion program”; and the county‐level ratio of OEWs to eligible children. Important HF enrollment predictors included family‐level ethnicity, age, number of hours a parent worked, and urban residence; and county‐level population size and outreach and media expenditure.

Conclusions. MC and HF outreach/enrollment efforts should target poorer and immigrant families (especially Latinos), older children, and children living in larger and urban counties. To reach uninsured eligible children, it is important to further simplify the application process and fund selected outreach efforts. Local health insurance expansion programs increase children's enrollment in MC.
Taxonomic Considerations in Listing Subspecies Under the U.S. Endangered Species Act
Authors: HAIG SUSAN M. , BEEVER ERIK A. , CHAMBERS STEVEN M. , DRAHEIM HOPE M. , DUGGER BRUCE D. , DUNHAM SUSIE , ELLIOTT‐SMITH ELISE , FONTAINE JOSEPH B. , KESLER DYLAN C. , KNAUS BRIAN J. , LOPES IARA F. , LOSCHL PETE , MULLINS THOMAS D. , SHEFFIELD LISA M.
Published: August 2006

Abstract: The U.S. Endangered Species Act (ESA) allows listing of subspecies and other groupings below the rank of species. This provides the U.S. Fish and Wildlife Service and the National Marine Fisheries Service with a means to target the most critical unit in need of conservation. Although roughly one‐quarter of listed taxa are subspecies, these management agencies are hindered by uncertainties about taxonomic standards during listing or delisting activities. In a review of taxonomic publications and societies, we found few subspecies lists and none that stated standardized criteria for determining subspecific taxa. Lack of criteria is attributed to a centuries‐old debate over species and subspecies concepts. Nevertheless, the critical need to resolve this debate for ESA listings led us to propose that minimal biological criteria to define disjunct subspecies (legally or taxonomically) should include the discreteness and significance criteria of distinct population segments (as defined under the ESA). Our subspecies criteria are in stark contrast to that proposed by supporters of the phylogenetic species concept and provide a clear distinction between species and subspecies. Efforts to eliminate or reduce ambiguity associated with subspecies‐level classifications will assist with ESA listing decisions. Thus, we urge professional taxonomic societies to publish and periodically update peer‐reviewed species and subspecies lists. This effort must be paralleled throughout the world for efficient taxonomic conservation to take place.
Measurement and Meaningfulness in Conservation Science
Authors: WOLMAN ABEL G.
Published: August 2006

Abstract:  Incomplete databases often require conservation scientists to estimate data either through expert judgment or other scoring, rating, and ranking procedures. At the same time, ecosystem complexity has led to the use of increasingly sophisticated algorithms and mathematical models to aid in conservation theorizing, planning, and decision making. Understanding the limitations imposed by the scales of measurement of conservation data is important for the development of sound conservation theory and policy. In particular, biodiversity valuation methods, systematic conservation planning algorithms, geographic information systems (GIS), and other conservation metrics and decision‐support tools, when improperly applied to estimated data, may lead to conclusions based on numerical artifact rather than empirical evidence. The representational theory of measurement is described here, and the description includes definitions of the key concepts of scale, scale type, and meaningfulness. Representational measurement is the view that measurement entails the faithful assignment of numbers to empirical entities. These assignments form scales that are organized into a hierarchy of scale types. A statement involving scales is meaningful if its truth value is invariant under changes of scale within scale type. I apply these concepts to three examples of measurement practice in the conservation literature. The results of my analysis suggest that conservation scientists do not always investigate the scale type of estimated data and hence may derive results that are not meaningful. Recognizing the complexity of observation and measurement in conservation biology, and the constraints that measurement theory imposes, the examples are accompanied by suggestions for informal estimation of the scale type of conservation data and for conducting meaningful analysis and synthesis of this information.
Quantifying Relative Extinction Risks and Targeting Intervention for the Orchid Flora of a Natural Park in the European Prealps
Authors: PIERCE SIMON , CERIANI ROBERTA M. , VILLA MAURO , CERABOLINI BRUNO
Published: August 2006

Abstract:  Conservation currently relies largely on hindsight because demographic studies identify population decline after the event. Nevertheless, the degree of aggregation within a population is an “instantaneous” characteristic with the potential to identify populations presently at greatest risk of genetic impoverishment (via Allee effects and in‐breeding depression) and local decline. We sought to determine the relative extinction risk for sympatric orchid species throughout Monte Barro natural park (Lecco, Italy), based on an index of dispersion (I) calculated from the size and location of subpopulations (recorded with GPS and mapped with GIS). Three population dispersion types were identified: (1) highly aggregated and locally abundant (large subpopulations restricted to particular sites; e.g., Gymnadenia conopsea [L.] R.Br.; I= 54.5); (2) widespread and moderately aggregated (opportunistic throughout the elevational range of the mountain; e.g., Listera ovata[L.] R.Br.; I = 18.9); and (3) weakly aggregated and locally rare (small, highly diffuse subpopulations; e.g., endemic Ophrys benacensis [Reisigl] O. & E. Danesch & Ehrend.; I = 4.4). Type 1 populations are more likely to respond to in situ intervention, whereas type 2 are relatively invasive species for which conservation intervention is not necessary, and type 3 are rare species that are least likely to respond to habitat management, for which ex situ conservation and population reinforcement would be most appropriate. Although our methodology provides only a “snapshot” of aboveground patterns of population dispersion, it can help target the application of in situ and ex situ conservation activities proactively and is of particular utility for parks for which a rapid assessment of local extinction risks is needed.
Externalities, Prospect Theory, and Social Construction: When Will Government Act, What Will Government Do?*
Authors: Steinacker Annette
Published: August 2006

Objectives. Political theories of agenda setting and policy choice are still limited in predicting when an issue will become salient and, once it has, what policy option will be used to address it. This article illustrates that for a large class of externality problems, perspectives from three other social science disciplines can refine those predictions.

Methods. A synthesis of implications from economics on assignment of property rights, loss aversion from prospect theory, and image of the policy target from social construction is used to determine the conditions under which issues gain attention and the likely policy solutions.

Results. Assignment of property rights establishes a baseline used to assess any further government actions, with losses from that base more likely to generate political attention. The assignment of rights also determines if a problem is defined as a negative or positive externality, which restricts the type of policies used to address the problem. This initial allocation of rights is in turn affected both by the political power and social construction of the groups involved.

Conclusions. The result is a bias in policy attention and outcomes strongly influenced by the norms used in assignment of property rights, which typically favor those generating the negative externality.
How Do Voters Form Expectations about the Parties' Chances of Winning the Election?*
Authors: Blais André , Bodet Marc André
Published: August 2006

Objective. This article examines the factors that form voters' perceptions of the parties' chances of winning at both the national and the local levels.

Method. We make use of the 1988 Canadian Election Study and we employ a HLM model to estimate the effect of individual‐level and contextual‐level variables.

Results. It is shown that voters' expectations are affected by a combination of “objective” contextual information and personal preferences (projection effects).

Conclusion. The basic contextual information that is utilized to ascertain local chances is the outcome of the previous election in the local constituency, whereas polls are crucial in the case of perceived national chances. We also find that the most politically aware are more strongly influenced by “objective” indicators.
Why Do Interest Groups Engage the Judiciary? Policy Wishes and Structural Needs*
Authors: Solberg Rorie Spill , Waltenburg Eric N.
Published: August 2006

Objectives. We test two competing explanations in order to answer the question: Why do organized interests choose to engage in advocacy behavior? The first turns on the notion that concerns with policy success are the principal forces affecting a group's choice. To a lesser degree, issues of group maintenance have also been identified as entering into organized interests' decisional calculus.

Method. Using survey data supplemented with confidential interviews of organized interests, we systematically examine the power of both accounts to explain the decision of groups to locate their energies in the federal judiciary. Consequently, in the penultimate section of the article, we specify and test a comprehensive model of interest group litigation behavior.

Results. In the resulting multivariate analysis, we find that forces associated with both avenues of explanation for interest group advocacy behavior have substantial statistical purchase and empirical traction.

Conclusion. Our findings did not show a dominate role for maintenance concerns; however, clearly, a group's assessment of where, and possibly whether, to act is not an easy calculation based on the receptiveness of a venue and the available balance in the bank account. Groups must attend to their members and their competition. Explanations of group advocacy omitting such concerns are inherently flawed.
Examining the Administration of Work Sanctions on the Frontlines of the Welfare System*
Authors: Lens Vicki
Published: August 2006

Objectives. Financial penalties, or sanctions, are a core mechanism for enforcing the work requirements of the Temporary Assistance for Needy Families program and helping clients achieve self‐sufficiency. This study's objective is to examine whether sanctions are being administered consistent with policy goals of encouraging work.

Methods. This study uses administrative fair hearing decisions, which are the product of an adversarial‐style procedure triggered when a client appeals an adverse decision by the agency, including work sanctions. Qualitative content analysis is used to analyze the decisions.

Results. The study found that despite organizational reforms, local offices had created the welfare‐to‐work version of an eligibility‐compliance culture, where sanctions were based primarily on attendance records and became a paper‐processing function. Transactions between clients and workers were often routinized and mechanical, resulting in improper and arbitrary sanctions that were reversed by the hearing officers nearly 50 percent of the time.

Conclusion. This study underscores the importance of scrutinizing and correcting agency errors that may undercut clients' engagement in work activities.
District Segregation, Race Legislation, and Black Enrollment in Charter Schools*
Authors: Renzulli Linda A.
Published: August 2006

Objective. This article examines how segregation at the school level within districts and charter school legislation predict black enrollment levels at local charter schools.

Methods. This study uses the Schools and Staffing Survey Charter School Data 1999–2000, Common Core of Data, and a unique data set of district test scores to estimate OLS regression models of black enrollment in charter schools on district racial segregation and race provisions in charter school legislation.

Results. Findings suggest that segregated school districts, those districts where whites and blacks are more unevenly distributed among schools, have a larger percentage of blacks enrolled in local charter schools than districts where schools are integrated. In addition, charter schools in states that do not have a racial clause have a smaller percent of blacks in their charter schools.

Conclusion. Findings suggest that black enrollment in charter schools is a function of district segregation and state policy.
Family Transitions, Economic Status, and Voter Turnout Among African‐American Inner‐City Women*
Authors: Plutzer Eric , Wiefek Nancy
Published: August 2006

Objectives. We examine voter turnout of inner‐city African‐American mothers, many of whom are single parents and endure long‐term, economic hardship. Previous research suggests that income is a more important factor among these groups than in the general population. We seek to understand the interplay of family structure, income, and voter turnout.

Methods. We explore these ideas using panel data on 754 mothers living in Chicago and interviewed as part of the 1967–1976 Woodlawn Community Study.

Results. We find that marital status has no effect when women are younger but over time single parents' turnout falls behind that of married parents. This is primarily due to factors related to income and income change.

Conclusions. Single mothers have lower rates of participation and, given the high rates of single parenthood in segregated inner‐city neighborhoods, this substantially diminishes the political voice of the nation's poor, contributing to class bias in the electorate.
Gender and Science in Developing Areas: Has the Internet Reduced Inequality?*
Authors: Paige Miller B. , Sooryamoorthy R. , Anderson Meredith , Palackal Antony , Shrum Wesley
Published: August 2006

Objective. This article examines the impact of the Internet on the research careers of female scientists in three developing areas: Ghana, Kenya, and Kerala, India. Most empirical studies of gender and science focus on the developed world, yet theoretical accounts emphasize more extreme differences in developing areas. Limited evidence from Africa and Asia shows gender inequity is restricted to a few key dimensions, broadly related to differences in human and social capital. Specifically, women are less likely to acquire an advanced degree and more likely to experience educational and organizational “localism.” Such localism is related to constraints on physical mobility that are widely expected to diminish with the introduction of the Internet.

Methods. Using longitudinal data on 1,147 scientists in Ghana, Kenya, and south India, we examine gender differences in human and social capital by conducting a series of t tests and chi‐square tests.

Results. We show that higher education and Internet access increased dramatically, but localism has not been reduced significantly and may be increasing.

Conclusions. This finding casts doubt on the presumption that the removal of communication constraints will soon reduce career differentials resulting from the mobility constraints on women professionals.
Sympathomimetic Infusion and Cardiac Repolarization: The Normative Effects of Epinephrine and Isoproterenol in Healthy Subjects
Authors: MAGNANO ANTHONY R. , TALATHOTI NARESH , HALLUR RAVINDRA , BLOOMFIELD DANIEL M. , GARAN HASAN
Published: August 2006

Introduction: Catecholamines are known to affect cardiac repolarization, and provocation with either isoproterenol or epinephrine has been proposed as a tool for uncovering latent repolarization abnormalities. This study systematically compares the effects of isoproterenol and epinephrine infusions on QT interval (QT), T waves and U waves in normal subjects.

Methods and Results: Twenty‐four normal subjects (29 ± 8 years) were evaluated during graded infusions of up to 0.30 μg/kg/minute epinephrine and 5.0 μg/minute isoproterenol. Heart rates at peak doses were 81 ± 13 bpm at 0.28 ± 0.04 μg/kg/minute epinephrine and 104 ± 5 bpm at 2.4 μg/minute isoproterenol. The longest absolute QT increase was 4 ± 5 msec above baseline during isoproterenol (P < 0.001) and 12 ± 23 msec during epinephrine (P = 0.07), while the longest corrected QT interval (QTc) increase was 67 ± 28 msec (P < 0.0001) and 79 ± 40 msec (P < 0.0001) above baseline during isoproterenol and epinephrine, respectively (P = 0.12 for difference). There was a 2‐fold increase in U‐wave amplitude during each intervention (P < 0.001). The specificity of paradoxical QT prolongation (≥30 msec at 0.05 μg/kg/minute or ≥35 msec at 0.10 μg/kg/minute epinephrine) and an increase in QTc ≥600 msec at any dose epinephrine were 100%. However, the specificity of other proposed criteria that utilized QTc measurement (≥30 msec at 0.10 μg/kg/minute or ≥65 msec at any dose) was poor whether all leads or only lead II were assessed.

Conclusion: Both epinephrine and isoproterenol are associated with QTc prolongation and amplification of the U wave in normal subjects. The specificity of proposed criteria for epinephrine provocation in diagnosis of the long‐QT syndrome is variable; however, paradoxical QT prolongation at low‐dose epinephrine or a QTc ≥600 msec is highly specific.
Analyses of co‐operative transitions in Plasmodium falciparumβ‐ketoacyl acyl carrier protein reductase upon co‐factor and acyl carrier protein binding
Authors: Karmodiya Krishanpal , Surolia Namita
Published: August 2006

The type II fatty acid synthase pathway of Plasmodium falciparum is a validated unique target for developing novel antimalarials because of its intrinsic differences from the type I pathway operating in humans. β‐Ketoacyl‐acyl carrier protein reductase is the only enzyme of this pathway that has no isoforms and thus selective inhibitors can be developed for this player of the pathway. We report here intensive studies on the direct interactions of Plasmodiumβ‐ketoacyl‐acyl carrier protein reductase with its cofactor, NADPH, acyl carrier protein, acetoacetyl‐coenzyme A and other ligands in solution, by monitoring the intrinsic fluorescence (λmax 334 nm) of the protein as a result of its lone tryptophan, as well as the fluorescence of NADPH (λmax 450 nm) upon binding to the enzyme. Binding of the reduced cofactor makes the enzyme catalytically efficient, as it increases the binding affinity of the substrate, acetoacetyl‐coenzyme A, by 16‐fold. The binding affinity of acyl carrier protein to the enzyme also increases by approximately threefold upon NADPH binding. Plasmodiumβ‐ketoacyl‐acyl carrier protein reductase exhibits negative, homotropic co‐operative binding for NADPH, which is enhanced in the presence of acyl carrier protein. Acyl carrier protein increases the accessibility of NADPH to β‐ketoacyl‐acyl carrier protein reductase, as evident from the increase in the accessibility of the tryptophan of β‐ketoacyl‐acyl carrier protein reductase to acrylamide, from 81 to 98%. In the presence of NADP+, the reaction proceeds in the reverse direction (Ka = 23.17 µm−1). These findings provide impetus for exploring the influence of ligands on the structure–activity relationship of Plasmodiumβ‐ketoacyl‐acyl carrier protein reductase.
HOW MUCH DO HIGH‐PERFORMANCE WORK PRACTICES MATTER? A META‐ANALYSIS OF THEIR EFFECTS ON ORGANIZATIONAL PERFORMANCE
Authors: COMBS JAMES , LIU YONGMEI , HALL ANGELA , KETCHEN DAVID
Published: August 2006

Although there is growing evidence that high performance work practices (HPWPs) affect organizational performance, varying sample characteristics, research designs, practices examined, and organizational performance measures used has led extant findings to vary dramatically, making the size of the overall effect difficult to estimate. We use meta‐analysis to estimate the effect size and test whether effects are larger for (a) HPWP systems versus individual practices, (b) operational versus financial performance measures, and (c) manufacturing versus service organizations. Statistical aggregation of 92 studies reveals an overall correlation that we estimate at .20. Also, the relationship is stronger when researchers examine systems of HPWPs and among manufacturers, but it appears invariant across performance measures. We use our findings as a basis to offer 4 suggestions intended to shape research practices such that future meta‐analyses might answer today's emerging questions.
SO YOU DIDN'T GET THE JOB … NOW WHAT DO YOU THINK? EXAMINING OPPORTUNITY‐TO‐PERFORM FAIRNESS PERCEPTIONS
Authors: SCHLEICHER DEIDRA J. , VENKATARAMANI VIJAYA , MORGESON FREDERICK P. , CAMPION MICHAEL A.
Published: August 2006

Although the last 10 years have witnessed an increased recognition of the importance of procedural fairness in selection contexts, most empirical research has focused on job relevance as the primary influence on fairness perceptions. There is reason to believe, however, that “opportunity‐to‐perform” (OTP) perceptions are also an important aspect of fairness perceptions and become particularly important following negative feedback (i.e., not receiving a job offer). Using both qualitative and quantitative data from a large sample of applicants to an agency of the U.S. government (N= 754), we examine (a) how OTP relates to fairness judgments, (b) how receiving negative feedback affects this relationship, (c) differences in OTP across a variety of different selection methods, and (d) determinants of OTP perceptions. Both qualitative and quantitative analyses confirmed that OTP was an important predictor of overall procedural fairness and was the single most important procedural rule after receiving negative feedback. Practical implications of this pattern, the obtained differences in OTP across assessments, and results regarding the determinants of OTP are discussed.
RELATIONSHIP OF PERSONALITY TRAITS AND COUNTERPRODUCTIVE WORK BEHAVIORS: THE MEDIATING EFFECTS OF JOB SATISFACTION
Authors: MOUNT MICHAEL , ILIES REMUS , JOHNSON ERIN
Published: August 2006

This study used path analysis to test a model that posits that relevant personality traits will have both direct relationships with counterproductive work behaviors (CPBs) and indirect relationships to CPBs through the mediating effects of job satisfaction. Based on a sample (n= 141) of customer service employees, results generally supported the hypothesized model for both boss‐ and self‐rated CPBs. Agreeableness had a direct relationship with interpersonal counterproductive work behaviors (CPB‐I); Conscientiousness had a direct relationship with organizational counterproductive work behaviors (CPB‐O); and, job satisfaction had a direct relationship to both CPB‐I and CPB‐O. In addition, job satisfaction partially mediated the relationship between Agreeableness and both CPB‐O and CPB‐I. Overall, results show that personality traits differentially predict CPBs and that employees' attitudes about their jobs explain, in part, these personality–behavior associations.
MOTIVATION TO LEARN AND COURSE OUTCOMES: THE IMPACT OF DELIVERY MODE, LEARNING GOAL ORIENTATION, AND PERCEIVED BARRIERS AND ENABLERS
Authors: KLEIN HOWARD J. , NOE RAYMOND A. , WANG CHONGWEI
Published: August 2006

This naturally occurring quasi‐experiment examined how learning goal orientation (LGO), delivery mode (classroom vs. blended learning), and the perception of barriers and enablers related to motivation to learn and course outcomes. Study participants were 600 students enrolled in either classroom or blended learning courses. As hypothesized, learners in the blended learning condition, high in LGO, and who perceived environmental features as enablers rather than barriers had significantly higher motivation to learn. Motivation to learn, in turn, was significantly related to course outcomes (satisfaction, metacognition, and grades). The mediation hypotheses received partial support. Finally, exploratory analyses revealed 3 significant interactions between delivery mode, LGO, and perceived barriers and enablers on motivation to learn and course satisfaction.
APPLYING U.S. EMPLOYMENT DISCRIMINATION LAWS TO INTERNATIONAL EMPLOYERS: ADVICE FOR SCIENTISTS AND PRACTITIONERS
Authors: POSTHUMA RICHARD A. , ROEHLING MARK V. , CAMPION MICHAEL A.
Published: August 2006

The question of whether U.S. employment discrimination laws apply to international employers is complex and involves multiple sources of legal authority including U.S. statutes, international treaties, and the laws of non‐American host countries. This article provides detailed and simplifying guidance to assist employers in working through that complexity. Based on an examination of 98 federal courts cases, this article identifies and explains 8 general guidelines for determining when U.S. laws apply to international employers (e.g., U.S. employees working abroad or “foreign” employees working in the United States). These guidelines are incorporated into an organizing framework or “decision tree” that leads employers through the various decisions that must be made to determine whether U.S. discrimination laws apply in a wide range of international employment situations. Guidance for industrial and organizational (I‐O) psychologists who advise international employers is provided and summarized in terms of general recommendations and conclusions.
Graded Regulation of the Kv2.1 Potassium Channel by Variable Phosphorylation
Authors: Park Kang-Sik , Mohapatra Durga P. , Misonou Hiroaki , Trimmer James S.
Published: August 2006

Dynamic modulation of ion channels by phosphorylation underlies neuronal plasticity. The Kv2.1 potassium channel is highly phosphorylated in resting mammalian neurons. Activity-dependent Kv2.1 dephosphorylation by calcineurin induces graded hyperpolarizing shifts in voltage-dependent activation, causing suppression of neuronal excitability. Mass spectrometry–SILAC (stable isotope labeling with amino acids in cell culture) identified 16 Kv2.1 phosphorylation sites, of which 7 were dephosphorylated by calcineurin. Mutation of individual calcineurin-regulated sites to alanine produced incremental shifts mimicking dephosphorylation, whereas mutation to aspartate yielded equivalent resistance to calcineurin. Mutations at multiple sites were additive, showing that variable phosphorylation of Kv2.1 at a large number of sites allows graded activity-dependent regulation of channel gating and neuronal firing properties.
Comment on "Computational Improvements Reveal Great Bacterial Diversity and High Metal Toxicity in Soil"
Authors: Bunge John , Epstein Slava S. , Peterson Daniel G.
Published: August 2006

Gans
et al
. (Reports, 26 August 2005, p. 1387) provided an estimate of soil bacterial species richness two orders of magnitude greater than previously reported values. Using a re-derived mathematical model, we reanalyzed the data and found that the statistical error exceeds the estimate by a factor of 26. We also note two potential sources of error in the experimental data collection and measurement procedures.
Switchable Surfactants
Authors: Liu Yingxin , Jessop Philip G. , Cunningham Michael , Eckert Charles A. , Liotta Charles L.
Published: August 2006

Many industrial applications that rely on emulsions would benefit from an efficient, rapid method of breaking these emulsions at a specific desired stage. We report that long-chain alkyl amidine compounds can be reversibly transformed into charged surfactants by exposure to an atmosphere of carbon dioxide, thereby stabilizing water/alkane emulsions or, for the purpose of microsuspension polymerization, styrene-in-water emulsions. Bubbling nitrogen, argon, or air through the amidinium bicarbonate solutions at 65°C reverses the reaction, releasing carbon dioxide and breaking the emulsion. We also find that the neutral amidines function as switchable demulsifiers of an aqueous crude oil emulsion, enhancing their practical potential.
The Molecular Architecture of Axonemes Revealed by Cryoelectron Tomography
Authors: Nicastro Daniela , Schwartz Cindi , Pierson Jason , Gaudette Richard , Porter Mary E. , McIntosh J. Richard
Published: August 2006

Eukaryotic flagella and cilia are built on a 9 + 2 array of microtubules plus >250 accessory proteins, forming a biological machine called the axoneme. Here we describe the three-dimensional structure of rapidly frozen axonemes from
Chlamydomonas
and sea urchin sperm, using cryoelectron tomography and image processing to focus on the motor enzyme dynein. Our images suggest a model for the way dynein generates force to slide microtubules. They also reveal two dynein linkers that may provide “hard-wiring” to coordinate motor enzyme action, both circumferentially and along the axoneme. Periodic densities were also observed inside doublet microtubules; these may contribute to doublet stability.
Pinwheels in the Quintuplet Cluster
Authors: Tuthill Peter , Monnier John , Tanner Angelle , Figer Donald , Ghez Andrea , Danchi William
Published: August 2006

The five enigmatic cocoon stars, after which the Quintuplet cluster was christened, have puzzled astronomers since their discovery. Their extraordinary cool, featureless thermal spectra have been attributed to various stellar types from young to highly evolved, whereas their absolute luminosities place them among the supergiants. We present diffraction-limited images from the Keck 1 telescope that resolve this debate with the identification of rotating spiral plumes characteristic of colliding-wind binary "pinwheel" nebulae. Such elegant spiral structures, found around high-luminosity Wolf-Rayet stars, have recently been implicated in the behavior of supernovae light curves in the radio and optical.
The Psychological Risks of Vietnam for U.S. Veterans: A Revisit with New Data and Methods
Authors: Dohrenwend Bruce P. , Turner J. Blake , Turse Nicholas A. , Adams Ben G. , Koenen Karestan C. , Marshall Randall
Published: August 2006

In 1988, the National Vietnam Veterans Readjustment Study (NVVRS) of a representative sample of 1200 veterans estimated that 30.9% had developed posttraumatic stress disorder (PTSD) during their lifetimes and that 15.2% were currently suffering from PTSD. The study also found a strong dose-response relationship: As retrospective reports of combat exposure increased, PTSD occurrence increased. Skeptics have argued that these results are inflated by recall bias and other flaws. We used military records to construct a new exposure measure and to cross-check exposure reports in diagnoses of 260 NVVRS veterans. We found little evidence of falsification, an even stronger dose-response relationship, and psychological costs that were lower than previously estimated but still substantial. According to our fully adjusted PTSD rates, 18.7% of the veterans had developed war-related PTSD during their lifetimes and 9.1% were currently suffering from PTSD 11 to 12 years after the war; current PTSD was typically associated with moderate impairment.
Seeking the Base of Our Branch
Authors: Begun David R.
Published: August 2006

The First Human
. The Race to Discover Our Earliest Ancestors.
By Ann GIbbons
. Doubleday, New York, 2006. 341 pp. $26, C$37. ISBN 0- 385-51226-0.

Highlighting recent findings, the author provides a popular account of the earliest fossil hominins and the competition among the scientists involved in the discoveries.
Controlling the Electronic Structure of Bilayer Graphene
Authors: Ohta Taisuke , Bostwick Aaron , Seyller Thomas , Horn Karsten , Rotenberg Eli
Published: August 2006

We describe the synthesis of bilayer graphene thin films deposited on insulating silicon carbide and report the characterization of their electronic band structure using angle-resolved photoemission. By selectively adjusting the carrier concentration in each layer, changes in the Coulomb potential led to control of the gap between valence and conduction bands. This control over the band structure suggests the potential application of bilayer graphene to switching functions in atomic-scale electronic devices.