bluuebunny/crossref_metadata_2025 huggingface dataset:
Stimulus affectivity of the Danish Word Association Test as measured by response heterogeneity and Rasch scaled number of prolonged reaction times
Authors: IVANOUW JAN
Published: January 2006

With the purpose of increasing the knowledge of the psychometric properties of the 70‐item Danish Word Association Test, data from three samples of non‐patients and psychiatric patients (N= 326) were used to provide two measures of affectivity of the stimulus words, response heterogeneity and reaction time prolongation. It was possible to fit an item response theory one‐parameter measurement (Rasch) model to the number of reaction time prolongations (≥3 seconds) for 54 of the stimulus words. Correlation between Rasch‐model item parameters and response heterogeneity was high (r= 0.86), while no correlation was found between either of these measures and frequency of the stimulus words in the Danish language. Both measures of stimulus affectivity supported a theoretically based classification of stimulus words as emotional or neutral. Response heterogeneity measures and Rasch measurement item and person parameters for reaction time prolongations are provided.
Adolescent adjustment and well‐being: Effects of parental divorce and distress
Authors: STØRKSEN INGUNN , RØYSAMB ESPEN , HOLMEN TURID L. , TAMBS KRISTIAN
Published: January 2006

This study investigates the long‐term effects of parental divorce on adolescent psychological adjustment and well‐being, and to what extent the effects are accounted for by parental psychological distress. Data were collected among 8,984 Norwegian adolescents (13–19 years) and their parents. Outcome variables were symptoms of anxiety and depression, subjective well‐being, and three areas of school problems. Parental divorce was found to be associated with both higher mean levels and larger variances in adolescent problems. Divorce and parental distress contributed independently to adolescent distress, supporting the notion of “double exposure” effects. The prevalence of adolescents with substantial distress symptoms was 14% among those with non‐distressed non‐divorced parents and 30% among those with divorced and distressed parents. In general effects remained when controlling for demographic factors. Long‐term effects of divorce on symptoms of anxiety and depression were stronger among girls than among boys.
Empirical and Hierarchical Bayesian Estimation in Finite Population Sampling under Structural Measurement Error Models
Authors: GHOSH MALAY , SINHA KARABI , KIM DALHO
Published: January 2006

Abstract.  This paper considers simultaneous estimation of means from several strata. A model‐based approach is taken, where the covariates in the superpopulation model are subject to measurement errors. Empirical Bayes (EB) and Hierarchical Bayes estimators of the strata means are developed and asymptotic optimality of EB estimators is proved. Their performances are examined and compared with that of the sample mean in a simulation study as well as in data analysis.
Direct Parametric Inference for the Cumulative Incidence Function
Authors: Jeong Jong-Hyeon , Fine Jason
Published: January 2006

In survival data that are collected from phase III clinical trials on breast cancer, a patient may experience more than one event, including recurrence of the original cancer, new primary cancer and death. Radiation oncologists are often interested in comparing patterns of local or regional recurrences alone as first events to identify a subgroup of patients who need to be treated by radiation therapy after surgery. The cumulative incidence function provides estimates of the cumulative probability of locoregional recurrences in the presence of other competing events. A simple version of the Gompertz distribution is proposed to parameterize the cumulative incidence function directly. The model interpretation for the cumulative incidence function is more natural than it is with the usual cause-specific hazard parameterization. Maximum likelihood analysis is used to estimate simultaneously parametric models for cumulative incidence functions of all causes. The parametric cumulative incidence approach is applied to a data set from the National Surgical Adjuvant Breast and Bowel Project and compared with analyses that are based on parametric cause-specific hazard models and nonparametric cumulative incidence estimation.
Estimating Percentile-Specific Treatment Effects in Counterfactual Models: A Case-Study of Micronutrient Supplementation, Birth Weight and Infant Mortality
Authors: Dominici Francesca , Zeger Scott L. , Parmigiani Giovanni , Katz Joanne , Christian Parul
Published: January 2006

Clinical trials of micronutrient supplementation are aimed at reducing the risk of infant mortality by increasing birth weight. Because infant mortality is greatest among the low birth weight (LBW) infants (2500 g or under), an effective intervention increases the birth weight among the smallest babies. The paper defines population and counterfactual parameters for estimating the treatment effects on birth weight and on survival as functions of the percentiles of the birth weight distribution. We use a Bayesian approach with data augmentation to approximate the posterior distributions of the parameters, taking into account uncertainty that is associated with the imputation of the counterfactuals. This approach is particularly suitable for exploring the sensitivity of the results to unverifiable modelling assumptions and other prior beliefs. We estimate that the average causal effect of the treatment on birth weight is 72 g (95% posterior regions 33–110 g) and that this causal effect is largest among the LBW infants. Posterior inferences about average causal effects of the treatment on birth weight are robust to modelling assumptions. However, inferences about causal effects for babies at the tails of the birth weight distribution can be highly sensitive to the unverifiable assumption about the correl-ation between the observed and the counterfactuals birth weights. Among the LBW infants who have a large causal effect of the treatment on birth weight, we estimate that a baby receiving the treatment has 5% less chance of death than if the same baby had received the control. Among the LBW infants, we found weak evidence supporting an additional beneficial effect of the treatment on mortality independent of birth weight.
Best Subset Selection of Autoregressive Models with Exogenous Variables and Generalized Autoregressive Conditional Heteroscedasticity Errors
Authors: So Mike K. P. , Chen Cathy W. S. , Liu Feng-Chi
Published: January 2006

We develop an efficient way to select the best subset autoregressive model with exogenous variables and generalized autoregressive conditional heteroscedasticity errors. One main feature of our method is to select important autoregressive and exogenous variables, and at the same time to estimate the unknown parameters. The method proposed uses the stochastic search idea. By adopting Markov chain Monte Carlo techniques, we can identify the best subset model from a large of number of possible choices. A simulation experiment shows that the method is very effective. Misspecification in the mean equation can also be detected by our model selection method. In the application to the stock-market data of seven countries, the lagged 1 US return is found to have a strong influence on the other stock-market returns.
Dynamic Factor Analysis with Non-Linear Temporal Aggregation Constraints
Authors: Proietti Tommaso , Moauro Filippo
Published: January 2006

The paper estimates an index of coincident economic indicators for the US economy by using time series with different frequencies of observation (monthly and quarterly, possibly with missing values). The model that is considered is the dynamic factor model that was proposed by Stock and Watson, specified in the logarithms of the original variables and at the monthly frequency, which poses a problem of temporal aggregation with a non-linear observational constraint when quarterly time series are included. Our main methodological contribution is to provide an exact solution to this problem that hinges on conditional mode estimation by iteration of the extended Kalman filtering and smoothing equations. On the empirical side the contribution of the paper is to provide monthly estimates of quarterly indicators, among which is the gross domestic product, that are consistent with the quarterly totals. Two applications are considered: the first dealing with the construction of a coincident index for the US economy, whereas the second does the same with reference to the euro area.
Efficient Survey Sampling of Households via Gaussian Quadrature
Authors: Arndt Channing , Kozlitina Julia , Preckel Paul V.
Published: January 2006

The collection of data through surveys is a costly and time-consuming process, particularly when complex economic data are involved. The paper presents an efficient approach, based on Gaussian quadrature, to survey sampling when some information is available about the target population. Using household data from Mozambique, we demonstrate that Gaussian quadrature subsamples, based on relatively easy to observe household characteristics such as size and educational attainment of members, generate better estimates of the moments of household expenditure than random samples of equal size.
APPROXIMATING GARCH‐JUMP MODELS, JUMP‐DIFFUSION PROCESSES, AND OPTION PRICING
Authors: Duan Jin‐Chuan , Ritchken Peter , Sun Zhiqiang
Published: January 2006

This paper considers the pricing of options when there are jumps in the pricing kernel and correlated jumps in asset prices and volatilities. We extend theory developed by Nelson (1990) and Duan (1997) by considering the limiting models for our approximating GARCH Jump process. Limiting cases of our processes consist of models where both asset price and local volatility follow jump diffusion processes with correlated jump sizes. Convergence of a few GARCH models to their continuous time limits is evaluated and the benefits of the models explored.
A UNIVERSAL OPTIMAL CONSUMPTION RATE FOR AN INSIDER
Authors: Øksendal Bernt
Published: January 2006

We consider a cash flow X(c) (t) modeled by the stochastic equation
image

where B(·) and are a Brownian motion and a Poissonian random measure, respectively, and c(t) ≥ 0 is the consumption/dividend rate. No assumptions are made on adaptedness of the coefficients μ, σ, θ, and c, and the (possibly anticipating) integrals are interpreted in the forward integral sense. We solve the problem to find the consumption rate c(·), which maximizes the expected discounted utility given by
image

Here δ(t) ≥ 0 is a given measurable stochastic process representing a discounting exponent and τ is a random time with values in (0, ∞), representing a terminal/default time, while γ≥ 0 is a known constant.
STOCK LIQUIDATION VIA STOCHASTIC APPROXIMATION USING NASDAQ DAILY AND INTRA‐DAY DATA
Authors: Yin G. , Zhang Q. , Liu F. , Liu R. H. , Cheng Y.
Published: January 2006

By focusing on computational aspects, this work is concerned with numerical methods for stock selling decision using stochastic approximation methods. Concentrating on the class of decisions depending on threshold values, an optimal stopping problem is converted to a parametric stochastic optimization problem. The algorithms are model free and are easily implementable on‐line. Convergence of the algorithms is established, second moment bound of estimation error is obtained, and escape probability from a neighborhood of the true parameter is also derived. Numerical examples using both daily closing prices and intra‐day data are provided to demonstrate the performance of the algorithms.
The Crisis of the Tariff Reform League and the Division of ‘Radical Conservatism’, c.1913–1922
Authors: THACKERAY DAVID A.
Published: January 2006

The term ‘Radical Conservatism’ has come to denote a group of Unionists who called for extensive government intervention and greater imperial consolidation in the opening decades of the twentieth century. Despite a revival of interest in the historical study of this movement, there has been little coverage of Radical Conservatism's difficult years during the Great War and its aftermath. This article examines the Tariff Reform League (TRL) which was the leading Radical Conservative pressure group during this period. It suggests that Radical Conservatism's more controversial, imperial policies had significantly more popular support than has previously been realized by historians. This article also challenges the idea that Radical Conservatism can be treated as a single, unified movement. It had several divisions throughout the early twentieth century, and effectively ruptured with Henry Page Croft's creation of the National Party in the autumn of 1917. The formation of this organization led to a crisis of confidence within the TRL, which precipitated its sudden decline in 1918–19.
The Effect of Works Councils on Employment Change
Authors: ADDISON JOHN T. , TEIXEIRA PAULINO
Published: January 2006

Despite recent changes in the relationship between unionism and various indicators of firm performance, there is one seeming constant in the Anglophone countries: unions at the workplace are associated with reduced employment growth of around −2.5% a year. Using German data, we examine the impact of the works council—that country's form of workplace representation—on employment change from 1993 to 2001. The German institution appears to have much the same negative effect on employment growth. That said, survival bias seems to play a small role, and works councils do not seem to further slow the tortuous pace of employment adjustment in Germany.
The Impact of Training Intensity on Establishment Productivity
Authors: ZWICK THOMAS
Published: January 2006

The empirical literature on productivity effects of continuing training is constantly increasing. However, the results on this subject differ widely. Explanations for this worrying diversity seem to lie in differences between countries, labor market institutions, and data generation on one hand, and in differences between the underlying estimation techniques on the other (Bartel, 2000). This paper concentrates on the latter problem and shows how results vary with different estimation techniques.
The Marginal Revenue Product of a Women's College Basketball Player
Authors: BROWN ROBERT W. , JEWELL R. TODD
Published: January 2006

This paper estimates the marginal revenue product of a premium women's college basketball player. Ordinary least squares estimates indicate that acquiring another one of these players generates nearly $250,000 annually for her team. Quantile regression estimates, however, show that these quantitative effects vary substantially across teams: Players at less successful programs generate little revenue for their team, while those at the elite programs generate considerable revenues. The results provide empirical evidence that schools may have the ability to capture economic rents from the best players at the top women's basketball programs.
Factors Related to Employees’ Desire to Join and Leave Unions
Authors: FRIEDMAN BARRY A. , ABRAHAM STEVEN E. , THOMAS RANDALL K.
Published: January 2006

Regression analyses based on a sample of 3372 nonunionized and unionized employees showed that, while the desire to join a union is associated with a wide range of work attitudes, perceived company performance, and facets of satisfaction, one's desire to leave one's union is associated with a narrow range of economic concerns. Implications of the findings are discussed in light of the declining unionization rate in the United States.
FROM INDIVIDUAL TO AGGREGATE LABOR SUPPLY: A QUANTITATIVE ANALYSIS BASED ON A HETEROGENEOUS AGENT MACROECONOMY*
Authors: Chang Yongsung , Kim Sun‐Bin
Published: January 2006

At the aggregate level, the labor‐supply elasticity depends on the reservation‐wage distribution. We present a model economy where workforce heterogeneity stems from idiosyncratic productivity shocks. The model economy exhibits the cross‐sectional earnings and wealth distributions that are comparable to those in the micro data. We find that the aggregate labor‐supply elasticity of such an economy is around 1, greater than a typical micro estimate.
BENCHMARKING FOR PRODUCTIVITY IMPROVEMENT: A HEALTH‐CARE APPLICATION*
Authors: Ackerberg Daniel A. , Machado Matilde P. , Riordan Michael H.
Published: January 2006

A methodology is developed and applied to compare the performance of publicly funded agencies providing treatment for alcohol abuse in Maine. The methodology estimates a Wiener process that determines the duration of completed treatments, while allowing for agency differences in the effectiveness of treatment, costs of treatment, standards for completion of treatment, patient attrition, and the characteristics of patient populations. Notably, the Wiener process model separately identifies agency fixed effects that describe differences in the effectiveness of treatment (“treatment effects”), and effects that describe differences in the unobservable characteristics of patients (“population effects”). The estimated model enables hypothetical comparisons of how different agencies would treat the same populations. The policy experiment of transferring the treatment practices of more cost‐effective agencies suggests that Maine could have significantly reduced treatment costs without compromising health outcomes by identifying and transferring best practices.
JOB SEARCH AND ASSET ACCUMULATION UNDER BORROWING CONSTRAINTS*
Authors: Rendon Sílvio
Published: January 2006

This article examines the relationship between wealth accumulation and job search dynamics. It proposes a model in which risk‐averse individuals search for jobs, save, and borrow to smooth their consumption. One motivation for accumulating wealth is to finance voluntary quits in order to search for better jobs. Using data on men from the National Longitudinal Survey (1979 cohort), I estimate the individual's dynamic decision problem. The results show that borrowing constraints are tight and reinforce the influence of wealth on job acceptance decisions, namely that more initial wealth and access to larger amounts of credit increase wages and unemployment duration.
Monitoring fluid chemistry in iron oxide–copper–gold‐related metasomatic processes, eastern Mt Isa Block, Australia
Authors: MARSHALL L. J. , OLIVER N. H. S.
Published: January 2006

Most researchers in the Proterozoic eastern Mt Isa Block, NW Queensland, Australia, favour magmatic fluid and salt sources for sodic‐(calcic) alteration and iron oxide–copper–gold mineralization. Here we compare spatial, mineralogic and stable isotope data from regional alteration assemblages with magmatic and magmatic‐hydrothermal interface rocks in order to track chemical and isotopic variations in fluid composition away from inferred fluid sources. Tightly clustered δ18O values for magnetite, quartz, feldspar and actinolite for igneous‐hosted samples reflect high temperature equilibration in the magmatic‐hydrothermal environment. In contrast, these minerals record predominantly higher δ18O values in regional alteration and Cu–Au mineralization. This dichotomy reflects partial equilibration with isotopically heavier wallrocks and slightly lower temperatures. Increases in Si concentrations of metasomatic amphiboles relative to igneous amphiboles in part reflect cooling of metasomatic fluids away from igneous rocks. Variations in XMg for metasomatic amphiboles indicate local wallrock controls on amphibole chemistry, while variations in XCl/XOH ratios for amphiboles (at constant XMg) indicate variable aH2O/aHCl ratios for metasomatic fluids. Biotite geochemistry also reflects cooling and both increases and decreases in aH2O/aHCl for fluids away from plutonic rocks. Decreased aH2O/aHCl ratios for metasomatic fluids reflect in part scavenging of chlorine out of meta‐evaporite sequences, although this process requires already saline fluids. Local increases in aH2O/aHCl ratios, as well as local decreases in δ18O values for some minerals (most notably haematite and epithermal‐textured quartz), may indicate ingress of low salinity, low δ18O fluids of possible meteoric origin late in the hydrothermal history of the region. Taken together, our observations are most consistent with predominantly magmatic sources for metasomatic fluids in the eastern Mt Isa Block, but record chemical and isotopic variations along fluid flow paths that may be important in explaining some of the diversity in alteration and mineralization styles in the district.
Investigation of coupled hydraulic–geomechanical processes at the KTB site: pressure‐dependent characteristics of a long‐term pump test and elastic interpretation using a geomechanical facies model
Authors: MCDERMOTT C. I. , LODEMANN M. , GHERGUT I. , TENZER H. , SAUTER M. , KOLDITZ O.
Published: January 2006

The German Continental Deep Drilling Program comprising a pilot borehole down to 4000 m and a main borehole down to 9101 m in southeast Germany (KTB) is continuing to provide a unique opportunity for the identification of important factors and processes in deep‐seated fluid and energy transfer. In situ stress conditions significantly impact flow, transport and exchange characteristics of fracture networks that dominate the permeability of crystalline reservoir rocks. In this paper, several scales of information are combined to present a fully three‐dimensional hydraulic finite element model of the principal KTB fault zones, and linked to a geomechanical model describing the alteration of the hydraulic parameters with stress changes caused by fluid extraction. The concept of geomechanical facies is introduced to define and characterize architectural elements in the subsurface system. Evaluation of a long‐term pump test in the KTB pilot hole, June 2002–July 2003, coupled with a geomechanical model gives an insight into some of the elastic and nonelastic processes controlling hydraulic transport in the basement rocks. Trends in the decline of the permeability and the degree of storage in the system could only partially be explained by elastic processes, clearly indicating the importance of nonelastic processes. A number of inelastic processes are suggested as areas for further research.
Exploiting the rodent model for studies on the pharmacology of lifespan extension
Authors: Nadon Nancy L.
Published: January 2006

The rodent is a particularly valuable model with which to test therapeutic interventions for aging, as rodent physiology is close enough to human physiology to give the findings relevance for human aging, and it is small enough to allow for use of statistically robust sample sizes. There are many rodent models to choose from, with advantages and disadvantages to each. The choice of model system, as well as other experimental design decisions such as diet and housing, is extremely important for the success of lifespan studies. These issues are discussed in this review of the use of the rodent model. The National Institute on Aging (NIA) Interventions Testing Program, which has grappled with all of these issues, is described.
Fibroblasts from long‐lived Snell dwarf mice are resistant to oxygen‐induced in vitro growth arrest
Authors: Maynard Scott P. , Miller Richard A.
Published: January 2006

Snell dwarf mice live longer than controls, and show lower age‐adjusted rates of lethal neoplastic diseases. Fibroblast cells from adult dwarf mice are resistant to the lethal effects of oxidative and nonoxidative stresses, including the carcinogen methyl methanesulfonate. We now report that dwarf‐derived fibroblasts are slow to enter the stage of growth arrest induced by culturing normal cells under standard culture conditions at 20% O2. Dwarf cells cultured at 20% O2 resemble control cells cultured at 3% O2 not only in their delayed growth arrest, but also in their rapid growth rates and resistance to both oxidative and nonoxidative forms of cytotoxic stress. Levels of the heat‐shock protein HSP‐70 respond to serum withdrawal and stress only in control cells, showing that intracellular signals are blunted in dwarf‐derived cells. These data suggest a model in which stable epigenetic changes induced in skin fibroblasts by the hormonal milieu of the Snell dwarf lead to resistance to multiple forms of injury, including the oxidative damage that contributes to growth arrest in vitro and neoplasia in intact mice.
Nitrones as therapeutics in age‐related diseases
Authors: Floyd Robert A.
Published: January 2006

Age‐related diseases deprive individuals of a higher quality of life and therefore therapeutics for their treatment provide significant potential. An overview of the observations of nitrones as potential therapeutics in several age‐related diseases is presented. Treatment of acute ischemic stroke is one condition where a nitrone (NXY‐059) is in late phase 3 clinical trials now. Also presented is a summary of the most recent work we have accomplished on the anticancer activity of the nitrones in a hepatocellular carcinoma. The mechanistic basis of action of these compounds in several animal models is not yet understood at the molecular levels; however, it does appear clear that their anti‐inflammatory properties are central to their action, which is based on their ability to down‐regulate exacerbated signal transduction processes.
Enhancing Adoptive Parenting: Devising Promising Interventions
Authors: Rushton Alan , Monck Elizabeth , Upright Helen , Davidson Mary
Published: January 2006

After describing the common problems of children placed for adoption from local authority care and the views and concerns of adopters as recipients of services, the article describes two contrasting interventions designed to enhance new adopters’ parenting skills and understanding. Aspects covered are the empirical and theoretical justifications for the interventions, the process of manualisation and the plan to evaluate the effectiveness of the interventions in a randomised controlled trial.
Clinical Advice to Courts on Children's Contact with their Parents following Parental Separation
Authors: Weir Kirk , Sturge Claire
Published: January 2006

This paper reviews the literature on the effect on children of continuing parental conflict following parental separation, but is largely based on the author's clinical and forensic experience of such cases. The approach to assessment has developed over 25 years of providing expert evidence to Courts in the UK.
In Vivo Stress Behavior in Cemented and Screw‐Retained Five‐Unit Implant FPDs
Authors: Karl Matthias , Taylor Thomas D. , Wichmann Manfred G. , Heckmann Siegfried M.
Published: January 2006

Purpose:
When fixing implant‐supported fixed partial dentures (FPDs), it is important to achieve passive fit. The objective of the in vivo study presented was to quantify the strain development during the fixation of screw‐ and cement‐retained FPDs.

Materials and Methods:
After informed patient consent had been obtained (Ethics commission Approval No. 2315; FAU Erlangen‐Nuremberg, Germany), four groups of five‐unit FPDs (five samples per group) were fabricated and investigated in vivo. Group 1: Cementable, repositioning technique impression, burn out plastic coping; Group 2: Screwable, pickup technique impression, burn out plastic coping; Group 3: Screwable, pickup technique impression, cast to gold cylinder; Group 4: Screwable, pickup technique impression, bonded to gold cylinder. Two strain gauges (SG) were attached to the pontics of each bridge (SG‐M and SG‐D) to measure the strains that occurred during either the cementing or screw‐in process. The final values were recorded for analysis.

Results:
The mean strain values (μm/m) for each SG were: Group 1: SG‐M 32 μm/m, SG‐D: 89 μm/m; Group 2: SG‐M 302 μm/m, SG‐D: 197 μm/m; Group 3: SG‐M 458 μm/m, SG‐D: 268 μm/m; Group 4: SG‐M 269 μm/m, SG‐D: 52 μm/m.

Conclusions:
Although the bridges were clinically acceptable, none of them revealed a truly passive fit with zero microstrain. In contrast to conventional screw‐retained bridges, cement retention seems to result in lower strain levels. Bonding bridge pontics to prefabricated implant components seems to allow both the retrievability of a screw‐retained bridge and produce moderate strain values.
A Practical Method for Chairside Repair of Debonded Porcelain Denture Teeth
Authors: Özcan Mutlu
Published: January 2006

The bonding of porcelain denture teeth to polymethylmethacrylate remains a clinical problem. In this article an alternative chairside method, based on silica coating and silanization for adhesion of denture tooth porcelain to polymethylmethacrylate is described.
Removable Partial Denture Education in U.S. Dental Schools
Authors: Petropoulos Vicki C. , Rashedi Behnoush
Published: January 2006

Purpose: A survey of U.S. dental schools was conducted in 2001 to determine the curricular structure, techniques, and materials used in predoctoral clinical removable partial denture (RPD) programs.

Materials and Methods: The questionnaire was mailed to the chairperson of the prosthodontic/restorative departments of 54 U.S. dental schools. Of these, 44 schools returned the completed survey, resulting in a response rate of 82%.

Results: Results from this survey show that a large majority of schools are using similar materials in clinical RPDs; for instance, using modeling compound for border molding final impression trays (61%) and using a semi‐adjustable articulator for mounting preliminary casts (90%) and final casts (98%). In addition, a large majority of schools are using similar techniques in clinical RPDs, such as border molding the edentulous areas of the final impression tray (80%) and using the altered cast impression technique (59%). A set post‐insertion protocol is present for patients who receive partial dentures in the majority of the schools (93%). Only 25% of schools reported incorporating new educational materials such as the use of Portrait artificial teeth at the predoctoral level. Eighteen percent of schools are allowing students to graduate without a set number of RPD clinical requirements as has been traditionally the case.

Conclusions: Predoctoral clinical RPD programs vary from school to school, yet a large percentage of schools agree on many topics.
A propensity score case‐control comparison of aprotinin and tranexamic acid in high‐transfusion‐risk cardiac surgery
Authors: Karkouti Keyvan , Beattie W. Scott , Dattilo Kathleen M. , McCluskey Stuart A. , Ghannam Mohammed , Hamdy Ahmed , Wijeysundera Duminda N. , Fedorko Ludwik , Yau Terrence M.
Published: January 2006

BACKGROUND:  Cardiac surgery with cardiopulmonary bypass may result in excessive fibrinolysis and platelet (PLT) dysfunction, resulting in impaired hemostasis and excessive blood loss. Prophylactic use of the antifibrinolytic drugs aprotinin and tranexamic acid is thought to prevent these hemostatic defects. Their relative clinical utility and safety in high‐transfusion‐risk cardiac surgery, however, is not known.

STUDY DESIGN AND METHODS:  Using propensity scores, 449 patients who received aprotinin for high‐transfusion‐risk cardiac surgery were matched to 449 patients who received tranexamic acid from a pool of 10,870 consecutive patients who underwent cardiac surgery at a single center, 586 of whom received aprotinin and the remainder of whom received tranexamic acid.

RESULTS:  The two matched groups were well balanced in terms of measured perioperative variables. Blood product transfusion rates were similar in the aprotinin and tranexamic acid groups: red blood cells, 79 percent versus 76 percent (p = 0.3); PLTs, 56 percent versus 50 percent (p = 0.06); and plasma, 66 percent versus 61 percent (p = 0.1). Adverse events rates were comparable in the two groups, except for renal dysfunction (defined as a greater than 50% increase in creatinine concentration during the first postoperative week to >100 µmol/L in women and >110 µmol/L in men or a new requirement for dialysis support), which occurred in 24 percent (107/449) of aprotinin patients and 17 percent (75/449) of tranexamic acid patients (p = 0.01).

CONCLUSIONS:  Aprotinin and tranexamic acid have similar hemostatic effectiveness in high‐transfusion‐risk cardiac surgery. Within the confines of propensity score matching, our results suggest that aprotinin may be associated with renal dysfunction.
Limitations of the hematocrit level to assess the need for red blood cell transfusion in hypovolemic anemic patients
Authors: Valeri C. Robert , Dennis Richard C. , Ragno Gina , MacGregor Hollace , Menzoian James O. , Khuri Shukri F.
Published: January 2006

BACKGROUND:  The transfusion trigger that physicians use to determine whether a patient requires a red blood cell (RBC) transfusion is the peripheral venous hematocrit (Hct) value. Although this measurement is an indicator of the concentration of RBCs in the blood, it does not reveal the RBC volume, plasma volume, or total blood volume, nor does it give any indication of whether the patient is hypovolemic, normovolemic, or hypervolemic.

STUDY DESIGN AND METHODS:  Two patient populations were studied: 41 consecutive patients subjected to elective vascular surgery and 20 consecutive patients subjected to cardiopulmonary bypass surgery. The RBC volume was measured with 51Cr‐ or 99mTc‐labeled autologous fresh RBCs, and the plasma volume and total blood volume were estimated from the measured RBC volume and the total body Hct level. Measurements made 1 to 2 and 24 hours after surgery were compared to the preoperative values for these two groups of patients.

RESULTS:  During the 24‐hour postoperative period, the RBC, plasma, and total blood volumes were reduced compared to the preoperative volumes. These patients were hypovolemic and anemic, and their Hct values during the 24‐hour postoperative period were increased by a mean of 4 to 5 volume‐percent compared to values that would be expected if they were normvolemic and anemic.

CONCLUSIONS:  The Hct values in hypovolemic anemic patients are elevated because the plasma volume does not increase to achieve the normovolemic anemic state.
Clinical effects of reverting from leukoreduced to nonleukoreduced blood in cardiac surgery
Authors: Fung Mark K. , Moore Karan , Ridenour Marilyn , Mook William , Triulzi Darrell J.
Published: January 2006

BACKGROUND:  A reduction in postoperative length of stay (PLOS) was recently demonstrated with the use of leukoreduced (LR) blood in cardiac surgery patients compared to a historical cohort who received non‐LR blood. Follow‐up data are now presented in a similar population after a 12‐month period in which LR blood was no longer routinely used.

STUDY DESIGN AND METHODS:  This is an extension of a study in which all patients admitted over a 12‐month period for open heart surgery were given LR blood (Group 2) and were compared against a historical cohort given non‐LR blood (Group 1). This study measures the outcomes of a new cohort of patients admitted during a 12‐month period where LR blood was no longer routinely used (Group 3).

RESULTS:  PLOS increased in patients who received transfusions with non‐LR blood (Group 3, n = 595) versus patients with LR blood (Group 2, n = 645; p = 0.045 by nonparametric rank U test). Mean PLOS increased from 9.5 days (95% confidence interval [CI], 8.9‐10.0) to 10.8 days (95% CI, 10.0‐11.6). In comparison, an earlier cohort who received non‐LR blood (Group 1, n = 501) had a mean PLOS of 10.1 days (95% CI, 9.4‐10.7). With the exception of decreased red blood cell (RBC) usage in Group 3, there were no significant differences in non‐RBC blood usage, estimated blood loss, bypass time, mediastinitis rates, operative mortality rate, or overall mix of cases.

CONCLUSIONS:  The use of non‐LR blood for cardiac surgery was associated with an increased PLOS compared to the use of LR blood and supports our previous demonstration of the benefits of LR blood in cardiac surgery.
Risks of Mortality and Morbidity from Worldwide Terrorism: 1968–2004
Authors: Bogen Kenneth T. , Jones Edwin D.
Published: January 2006

Worldwide data on terrorist incidents between 1968 and 2004 gathered by the RAND Corporation and the Oklahoma City National Memorial Institute for the Prevention of Terrorism (MIPT) were assessed for patterns and trends in morbidity/mortality. Adjusted data analyzed involve a total of 19,828 events, 7,401 “adverse” events (each causing ≥ 1 victim), and 86,568 “casualties” (injuries), of which 25,408 were fatal. Most terror‐related adverse events, casualties, and deaths involved bombs and guns. Weapon‐specific patterns and terror‐related risk levels in Israel (IS) have differed markedly from those of all other regions combined (OR). IS had a fatal fraction of casualties about half that of OR, but has experienced relatively constant lifetime terror‐related casualty risks on the order of 0.5%—a level 2 to 3 orders of magnitude more than those experienced in OR that increased approximately 100‐fold over the same period. Individual event fatality has increased steadily, the median increasing from 14% to 50%. Lorenz curves obtained indicate substantial dispersion among victim/event rates: about half of all victims were caused by the top 2.5% (or 10%) of harm‐ranked events in OR (or IS). Extreme values of victim/event rates were approximated fairly well by generalized Pareto models (typically used to fit to data on forest fires, sea levels, earthquakes, etc.). These results were in turn used to forecast maximum OR‐ and IS‐specific victims/event rates through 2080, illustrating empirically‐based methods that could be applied to improve strategies to assess, prevent, and manage terror‐related risks and consequences.
The Bioaccessibility of Lead (Pb) from Vacuumed House Dust on Carpets in Urban Residences
Authors: Yu Chang Ho , Yiin Lih‐Ming , Lioy Paul J.
Published: January 2006

Risk assessments for toxicants in environmental media via oral exposure often rely on measurements of total concentration in a collected sample. However, the human digestive system cannot dissolute all of a toxicant present in the binding matrix, and cannot absorb it with nearly 100% efficiency. In vitro bioaccessibility has been developed as a method to estimate oral bioavailability of a toxicant using a physiologically‐based extraction procedure. Bioaccessibility measurements are more physiologically relevant than strong acid leaching measurements of concentration. A method for measuring bioaccessible lead in house dust was derived from the bioaccessibility method currently used for heavy metals in contaminated soils. House dust was collected from carpets in typical urban residences. Bioaccessible lead was measured in house dust (<75 μm) from the homes of 15 participants. The bioaccessibility ranged from 52.4% to 77.2% in gastric fluid, and 4.9% to 32.1% in intestinal fluid. House dust samples from five homes were analyzed to assess the relationship among lead bioaccessibility of three particle size fractions (<75, 75–150, and 150–250 μm). Changes in lead bioaccessibility as a function of particle size fraction were not significant for gastric fluid (p= 0.7019); however they were significant for intestinal fluid (p= 0.0067). This decrease of bioaccessibility may result from the readsorption of dissolved lead onto the dust particles or precipitation of lead with phosphates in a high‐pH environment. The bioaccessibility data obtained for two biofluids were applied to the IEUBK model, and results for intestinal bioaccessibility of lead provide support for the model default value of 30% lead bioavailability of dust as a reasonable population indicator for dose, but the higher values for gastric bioaccessibility of lead appeared to provide an upper bound that approached actual blood lead levels in the children living in the studied homes. This upper bound seemed to overcome some of the limitations of the model when it lacks child‐specific activity data and characterization of all exposure routes.
Book Reviews
Authors: Smith Preston G.
Published: January 2006

Books reviewed in this issue:

The PDMA Handbook of New Product Development

Product Leadership: Pathways to Profitable Innovation

Juice: The Creative Fuel that Drives World‐Class Inventors

Breakthrough: Stories and Strategies of Radical Innovation

Strategic Management of Technological Innovation

Strategic Technology Management: Building Bridges between Sciences, Engineering, and Business Management
Primary Cardiac Non‐Hodgkin's Lymphoma Diagnosed by Transthoracic Echocardiography
Authors: Konety Suma H. , Wooldridge James E. , Kerber Richard E.
Published: January 2006

Primary cardiac lymphomas are extremely rare and can be diagnosed by echocardiography. We present the case of a 79‐year‐old man with an intracardiac mass, shown to be an aggressive large B‐cell lymphoma by mediastinal aspiration, who had rapid regression of the tumor following one cycle of chemotherapy.
Isolated Supravalvular Pulmonary Artery Ridge in a 70‐Year‐Old Man
Authors: Gilman Gregory , Hansen William H. , Glockner James F. , Hagler Donald J. , Callahan Mark J.
Published: January 2006

Transthoracic echocardiography allows noninvasive assessment of the structure and function of the great vessels of the heart. We report a case of a 70‐year‐old man who had an isolated, mildly obstructive, supravalvular pulmonary artery ridge that was detected incidentally with transthoracic echocardiography. This report confirms the utility of transthoracic echocardiography in the detection of this condition and discusses quantification of this rare anomaly.
Spontaneous Coronary Artery Dissection during a Dobutamine Stress Echocardiography
Authors: Karabinos Ilias , Papadopoulos Anastasios , Koulouris Spyridon , Kranidis Athanasios , Korovesis Socrates , Katritsis Demosthenes
Published: January 2006

We report a case of a spontaneous dissection of the right coronary artery during a dobutamine stress echocardiography (DSE) study in a middle‐aged male. Our patient experienced a severe retrosternal pain of abrupt onset during the DSE study, whereas EKG was evident of significant ST segment elevation in II, III, avF, and V5‐V6 leads, followed by an accelerated idioventricular rhythm. Immediate coronary angiogram revealed a minor dissection of the distal part of the right coronary artery.
The Double Jeopardy of Blunt Chest Trauma: A Case Report and Review
Authors: Varahan Subha L. , Farah George M. , Caldeira Christiano C. , Hoit Brian D. , Askari Arman T.
Published: January 2006

Cardiac injury, specifically valvular rupture, must be considered after blunt chest trauma even in previously healthy patients. Isolated mitral regurgitation (MR) and tricuspid regurgitation (TR) due to blunt chest trauma are rare phenomena. More unique is simultaneous complete papillary muscle rupture of the mitral valve (MV) and tricuspid valve (TV) with only four patients being previously reported in the literature. This case describes a patient with complete transection of the posteromedial papillary muscle of the MV with severe MR and a concomitant flail TV with severe TR following a motor vehicular accident. The importance of transthoracic and transesophageal echocardiography in the early evaluation of patients following blunt chest trauma is also highlighted by this case.
Tissue Doppler Echocardiography Reveals Insufficient Contractile Reserve Recruitment during Effort in Subjects with Mitral Valve Prolapse and Those with Thick Mitral Valve
Authors: Zampoulakis John D. , Karavidas Apostolos I. , Matsakas Evangellos , Lazaros George A. , Karaminas Naoum T. , Fotiadis Ioannis N. , Panou Fotis K. , Zacharoulis Apostolos
Published: January 2006

Objective: To assess by tissue Doppler echocardiography (TDE), the tissue velocities, both at rest and after exercise stress testing, in subjects with mitral valve prolapse (MVP) and those with thick mitral valve (TMV). Methods: Twenty individuals with typical MVP, 30 with TMV, and 30 healthy controls were enrolled. TDE was performed at the basal‐inferior wall and the parameters evaluated were the S, Em, and Am velocities, as well as the Em/Am ratio. Results: The mean S‐wave at rest was higher in subjects with MVP compared to that of the TMV (P < 0.01) and the control groups (P = 0.00005), whereas after exercise it was higher in the control group compared to either MVP (P = 0.013) or TMV group (P = 0.00002). The mean Em wave at rest was higher in the control individuals both at rest (P = 0.007 compared with MVP group and P = 0.013 compared with TMV group), and after exercise (P = 0.0002 and 0.0009, respectively). The Am wave in the MVP group was higher compared with TMV and control subjects at rest (P = 0.022 and 0.00001, respectively) but it was not after exercise (P = ns for both comparisons). The Em/Am ratio of the control group at rest was higher than that of the MVP (P = 0.0000) and TMV (P = 0.00028) groups. However, after exercise, it was higher only when compared with the MVP group (P = 0.016). Conclusions: Subjects with MVP and those with TMV exhibit a less effective contractile response to exercise compared to healthy individuals. Some degree of diastolic dysfunction, particularly after exercise, was also detected in the individuals with MVP. (ECHOCARDIOGRAPHY, Volume 23, February 2006)
Echocardiographic Diagnosis of a Case with Giant Right Atrial Aneurysm
Authors: Yildirim Nesligül , Gölbaşi Zehra
Published: January 2006

Right atrial aneurysm (RAA) is a very rare anomaly. Rarer still is its association with atrial septal defect (ASD). We reported a case of a 42‐year‐old woman with giant RRA and secundum type ASD detected by means of transthoracic echocardiography. (ECHOCARDIOGRAPHY, Volume 23, February 2006)
Usefulness of Myocardial Contrast Echocardiography Early After Acute Myocardial Infarction
Authors: Cianciulli Tomás F. , Lax Jorge A. , Beck Martín A. , Masoli Osvaldo H. , Redruello Marcela F. , Saccheri María C. , Guevara Eduardo , Gagliardi Juan A. , Dorelle Adriana N. , Prezioso Horacio A.
Published: January 2006

Objectives: (1) Evaluate wall motion and perfusion abnormalities after reperfusion therapy of the culprit lesion, (2) delineate the ability of myocardial contrast echocardiography (MCE) to evaluate the microvasculature after reperfusion, in order to distinguish between stunning and necrosis in the risk area. Methods: We analyzed 446 segments from 28 patients, 10 normal controls (160 segments), and 18 with a first AMI (286 segments). MCE was obtained with Optison and a two‐dimensional echocardiography was performed at 3 months post acute myocardial infarction (AMI). Results: In the group with AMI, we analyzed 286 segments, of which 107 had wall motion abnormalities (WMA) related to the culprit artery. Two subgroups were identified: Group I with WMA and normal perfusion (50 segments, 47%) and Group II with WMA and perfusion defects (57 segments, 53%). According to the 2D echocardiogram at 3 months, they were further subdivided into: Group IA: with wall motion improvement (stunning): 18 segments, 36%, Group IB: without wall motion improvement: 32 segments, 64%, Group IIA: with wall motion improvement: 12 segments, 21%, Group IIB: without wall motion improvement (necrosis): 45 segments, 79%. Conclusions: (1) The presence of myocardial perfusion in segments with WMA immediately after AMI reperfusion therapy predicts viability in most patients. Conversely, the lack of perfusion is not an absolute indicator of the presence of necrosis. (2) Perfusion defects allow to detect patients with thrombolysis in myocardial infarction (TIMI) 3 flow and “no‐reflow” phenomenon who will not show improved wall motion in the 2D echocardiogram. However, some patients with initial no‐reflow could have microvascular stunning and their regional contractile function will normalize after a recovery period.