bluuebunny/crossref_metadata_2025 huggingface dataset:
Contribution of Impaired Myocardial Insulin Signaling to Mitochondrial Dysfunction and Oxidative Stress in the Heart
Authors: Boudina Sihem , Bugger Heiko , Sena Sandra , O'Neill Brian T. , Zaha Vlad G. , Ilkun Olesya , Wright Jordan J. , Mazumder Pradip K. , Palfreyman Eric , Tidwell Timothy J. , Theobald Heather , Khalimonchuk Oleh , Wayment Benjamin , Sheng Xiaoming , Rodnick Kenneth J. , Centini Ryan , Chen Dong , Litwin Sheldon E. , Weimer Bart E. , Abel E. Dale
Published: February 2009

Background—

Diabetes-associated cardiac dysfunction is associated with mitochondrial dysfunction and oxidative stress, which may contribute to left ventricular dysfunction. The contribution of altered myocardial insulin action, independent of associated changes in systemic metabolism, is incompletely understood. The present study tested the hypothesis that perinatal loss of insulin signaling in the heart impairs mitochondrial function.

Methods and Results—

In 8-week-old mice with cardiomyocyte deletion of insulin receptors (CIRKO), inotropic reserves were reduced, and mitochondria manifested respiratory defects for pyruvate that was associated with proportionate reductions in catalytic subunits of pyruvate dehydrogenase. Progressive age-dependent defects in oxygen consumption and ATP synthesis with the substrate glutamate and the fatty acid derivative palmitoyl-carnitine were observed. Mitochondria also were uncoupled when exposed to palmitoyl-carnitine, in part as a result of increased reactive oxygen species production and oxidative stress. Although proteomic and genomic approaches revealed a reduction in subsets of genes and proteins related to oxidative phosphorylation, no reductions in maximal activities of mitochondrial electron transport chain complexes were found. However, a disproportionate reduction in tricarboxylic acid cycle and fatty acid oxidation proteins in mitochondria suggests that defects in fatty acid and pyruvate metabolism and tricarboxylic acid flux may explain the mitochondrial dysfunction observed.

Conclusions—

Impaired myocardial insulin signaling promotes oxidative stress and mitochondrial uncoupling, which, together with reduced tricarboxylic acid and fatty acid oxidative capacity, impairs mitochondrial energetics. This study identifies specific contributions of impaired insulin action to mitochondrial dysfunction in the heart.
Electrophysiological Consequences of Dyssynchronous Heart Failure and Its Restoration by Resynchronization Therapy
Authors: Aiba Takeshi , Hesketh Geoffrey G. , Barth Andreas S. , Liu Ting , Daya Samantapudi , Chakir Khalid , Dimaano Veronica Lea , Abraham Theodore P. , O'Rourke Brian , Akar Fadi G. , Kass David A. , Tomaselli Gordon F.
Published: February 2009

Background—

Cardiac resynchronization therapy (CRT) is widely applied in patients with heart failure and dyssynchronous contraction (DHF), but the electrophysiological consequences of CRT in heart failure remain largely unexplored.

Methods and Results—

Adult dogs underwent left bundle-branch ablation and either right atrial pacing (190 to 200 bpm) for 6 weeks (DHF) or 3 weeks of right atrial pacing followed by 3 weeks of resynchronization by biventricular pacing at the same pacing rate (CRT). Isolated left ventricular anterior and lateral myocytes from nonfailing (control), DHF, and CRT dogs were studied with the whole-cell patch clamp. Quantitative polymerase chain reaction and Western blots were performed to measure steady state mRNA and protein levels. DHF significantly reduced the inward rectifier K
+
current (
I
K1
), delayed rectifier K
+
current (
I
K
), and transient outward K
+
current (
I
to
) in both anterior and lateral cells. CRT partially restored the DHF-induced reduction of
I
K1
and
I
K
but not
I
to
, consistent with trends in the changes in steady state K
+
channel mRNA and protein levels. DHF reduced the peak inward Ca
2+
current (
I
Ca
) density and slowed
I
Ca
decay in lateral compared with anterior cells, whereas CRT restored peak
I
Ca
amplitude but did not hasten decay in lateral cells. Calcium transient amplitudes were depressed and the decay was slowed in DHF, especially in lateral myocytes. CRT hastened the decay in both regions and increased the calcium transient amplitude in lateral but not anterior cells. No difference was found in Ca
V
1.2 (α1C) mRNA or protein expression, but reduced Ca
V
β2 mRNA was found in DHF cells. DHF reduced phospholamban, ryanodine receptor, and sarcoplasmic reticulum Ca
2+
ATPase and increased Na
+
-Ca
2+
exchanger mRNA and protein. CRT did not restore the DHF-induced molecular remodeling, except for sarcoplasmic reticulum Ca
2+
ATPase. Action potential durations were significantly prolonged in DHF, especially in lateral cells, and CRT abbreviated action potential duration in lateral but not anterior cells. Early afterdepolarizations were more frequent in DHF than in control cells and were reduced with CRT.

Conclusions—

CRT partially restores DHF-induced ion channel remodeling and abnormal Ca
2+
homeostasis and attenuates the regional heterogeneity of action potential duration. The electrophysiological changes induced by CRT may suppress ventricular arrhythmias, contribute to the survival benefit of this therapy, and improve the mechanical performance of the heart.
Thirty-Year Trends (1975 to 2005) in the Magnitude of, Management of, and Hospital Death Rates Associated With Cardiogenic Shock in Patients With Acute Myocardial Infarction
Authors: Goldberg Robert J. , Spencer Frederick A. , Gore Joel M. , Lessard Darleen , Yarzebski Jorge
Published: February 2009

Background—

Limited information is available about potentially changing and contemporary trends in the incidence and hospital death rates of cardiogenic shock complicating acute myocardial infarction. The objectives of our study were to examine 3-decade-long trends (1975 to 2005) in the incidence rates of cardiogenic shock complicating acute myocardial infarction, patient characteristics and treatment practices associated with this clinical complication, and hospital death rates in residents of a large central New England community hospitalized with acute myocardial infarction at all area medical centers.

Methods and Results—

The study population consisted of 13 663 residents of the Worcester (Mass) metropolitan area hospitalized with acute myocardial infarction at all greater Worcester medical centers during 15 annual periods between 1975 and 2005. Overall, 6.6% of patients developed cardiogenic shock during their index hospitalization. The incidence rates of cardiogenic shock remained stable between 1975 and the late 1990s but declined in an inconsistent manner thereafter. Patients in whom cardiogenic shock developed had a significantly greater risk of dying during hospitalization (65.4%) than those who did not develop cardiogenic shock (10.6%) (
P
<0.001). Encouraging increases in hospital survival in patients with cardiogenic shock, however, were observed from the mid-1990s to our most recent study years. Several patient demographic and clinical characteristics were associated with an increased risk for developing cardiogenic shock.

Conclusions—

Our findings indicate improving trends in the hospital prognosis associated with cardiogenic shock. Given the high death rates associated with this clinical complication, monitoring future trends in the incidence and death rates and the factors associated with an increased risk for developing cardiogenic shock remains warranted.
Predictors of Initial Nontherapeutic Anticoagulation With Unfractionated Heparin in ST-Segment Elevation Myocardial Infarction
Authors: Cheng Susan , Morrow David A. , Sloan Sarah , Antman Elliott M. , Sabatine Marc S.
Published: February 2009

Background—

Although weight-based nomograms have improved the efficacy and safety of dosing unfractionated heparin in ST-segment elevation myocardial infarction, achieving therapeutic anticoagulation in practice remains challenging.

Methods and Results—

In the Enoxaparin and Thrombolysis in Reperfusion for Acute Myocardial Infarction Treatment-Thrombolysis in Myocardial Infarction (ExTRACT-TIMI) 25 study, 20 506 patients with ST-segment elevation myocardial infarction were randomized to enoxaparin or unfractionated heparin, the latter dosed according to the American College of Cardiology/American Heart Association weight-based nomogram with centrally monitored activated partial thromboplastin times (aPTTs). A total of 6055 patients received study unfractionated heparin and a fibrin-specific lytic and had an initial aPTT drawn within 4 to 8 hours of starting therapy. Despite close adherence to recommended dosing, only 33.8% of initial aPTTs were therapeutic (1.50 to 2.00 times control); 13.2% were markedly low (<1.25 times); and 16.3% were markedly high (≥2.75 times). Markedly high aPTTs were more likely in patients who were older (adjusted risk ratio [RR
adj
], 1.14 per decade;
P
=0.001), were female (RR
adj
, 1.46;
P
<0.001), were of lower weight (RR
adj
, 1.19 per 10-kg decrease;
P
<0.001) or had renal dysfunction (RR
adj
, 1.08 per 0.2-mg/dL increase in serum creatinine;
P
=0.006). Markedly high aPTTs were associated with increased risk of TIMI major or minor bleeding by 48 hours (odds ratio, 2.11;
P
=0.004); markedly low aPTTs tended to be associated with increased risk of fatal or nonfatal reinfarction by 48 hours (odds ratio, 2.19;
P
=0.057).

Conclusions—

Despite the use of a standard weight-based unfractionated heparin nomogram in ST-segment elevation myocardial infarction, nontherapeutic anticoagulation is frequent and more likely among certain vulnerable patient groups, with excess anticoagulation associated with increased bleeding and inadequate anticoagulation associated with reinfarction. These findings should be considered when dosing unfractionated heparin in support of fibrinolytic therapy.
Long-Term Trends in Myocardial Infarction Incidence and Case Fatality in the National Heart, Lung, and Blood Institute’s Framingham Heart Study
Authors: Parikh Nisha I. , Gona Philimon , Larson Martin G. , Fox Caroline S. , Benjamin Emelia J. , Murabito Joanne M. , O'Donnell Christopher J. , Vasan Ramachandran S. , Levy Daniel
Published: February 2009

Background—

Whereas the prevalence of coronary heart disease risk factors has declined over the past decades in the United States, acute myocardial infarction (AMI) rates have been steady. We hypothesized that this paradox is due partly to the advent of increasingly sensitive biomarkers for AMI diagnosis.

Methods and Results—

In Framingham Heart Study participants over 4 decades, we compared the incidence and survival rates of initial AMI diagnosis by ECG (AMI-ECG) regardless of biomarkers with those based exclusively on infarction biomarkers (AMI-marker). We used Poisson regression to calculate annual incidence rates of first AMI over 4 decades (1960 to 1969, 1970 to 1979, 1980 to 1989, and 1990 to 1999) and compared rates of AMI-ECG with rates of AMI-marker. Cox proportional-hazards analysis was used to compare AMI case fatality over 4 decades. In 9824 persons (54% women; follow-up, 212 539 person-years; age, 40 to 89 years), 941 AMIs occurred, including 639 AMI-ECG and 302 AMI-marker events. From 1960 to 1999, rates of AMI-ECG declined by ≈50% and rates of AMI-marker increased ≈2-fold. Crude 30-day, 1-year, and 5-year case fatality rates in 1960 to 1969 and 1990 to 1999 were 0.20 and 0.14, 0.24 and 0.21, and 0.45 and 0.41, respectively. Age- and sex-adjusted 30-day, 1-year, and 5-year AMI case fatality declined by 60% in 1960 to 1999 (
P
for trend <0.001), with parallel declines noted after AMI-ECG and AMI-marker.

Conclusions—

Over the past 40 years, rates of AMI-ECG have declined by 50%, whereas rates of AMI-marker have doubled. Our findings offer an explanation for the apparently steady national AMI rates in the face of improvements in primary prevention.
Characteristics and Outcomes of Revascularized Patients With Hypertension
Authors: Denardo Scott J. , Messerli Franz H. , Gaxiola Efrain , Aranda Juan M. , Cooper-DeHoff Rhonda M. , Handberg Eileen M. , Gong Yan , Champion Annette , Zhou Qian , Pepine Carl J.
Published: February 2009

Our understanding of the growing population of revascularized patients with hypertension is limited. We retrospectively analyzed the International Verapamil SR-Trandolapril Study, which randomized coronary artery disease patients with hypertension to either verapamil SR- or atenolol-based treatment strategies, focusing on characteristics and outcomes of 6166 previously revascularized patients compared with 16 410 nonrevascularized patients. Revascularized patients had a history of coronary artery bypass grafting (45.2%), percutaneous coronary intervention (42.1%), or both (12.8%). Compared with nonrevascularized patients, revascularized patients at baseline demonstrated a higher prevalence of coronary artery disease risk factors and risk conditions (
P
<0.001). This higher prevalence was the principal cause of a higher incidence of primary outcome (death, nonfatal myocardial infarction, or nonfatal stroke) among revascularized patients (14.2% versus 8.5% for nonrevascularized patients;
P
<0.001). However, both patient groups demonstrated a relatively low incidence of subsequent revascularization (5.1% versus 1.5% respectively;
P
<0.0001). Associations between adjusted hazard ratio for primary outcome and follow-up blood pressure appeared “J shaped” for both patient groups. Because, as a group, revascularized patients with hypertension had worse outcomes compared with nonrevascularized patients, management of blood pressure to a specific target in future studies could result in improved outcomes.
Heterogeneity of L- and T-Channels in the Vasculature
Authors: Ball Christine J. , Wilson David P. , Turner Stuart P. , Saint David A. , Beltrame John F.
Published: February 2009

Clinical studies suggest that T-type Ca
2+
channel blockade may have incremental benefits over conventional L-channel blockade, particularly in microvascular disorders. This study examined functional vasomotor differences in L- and T-channel blockade between large and small vessels and compared the abundance of the L- and T-type channels in these vessels. The inhibition of endothelin-1 and potassium-induced vascular contractile responses by L-channel blockers (verapamil and nifedipine) was compared with combined L- and T-channel blockers (mibefradil and efonidipine) in large (rat aorta) and small (rat mesenteric and human subcutaneous) vessels using wire myography. All 4 of the Ca
2+
channel blockers inhibited contractile responses to a similar extent in large rat vessels; however, in rat microvessels, the combined L- and T-channel blockers produced significantly greater inhibition of contraction than L-channel blockers alone. The significance of this differential T-channel effect in microvessels was further supported by the following: (1) a greater abundance of T-channels compared with L-channels in microvessels but not in large vessels; (2) demonstration of divergent Ca
2+
channel blocker responses in human microvessels; (3) incremental inhibition of constrictor responses with combined L- and T-Ca
2+
channel blockers despite maximal L-channel blockade; (4) the use of structurally diverse Ca
2+
channel blockers with varied affinity for L- and T-channels; (5) the use of pharmacodynamically and therapeutically appropriate Ca
2+
channel blocker concentrations; (6) confirmation of contractile agonist independent responses; and (7) exclusion of an endothelium-dependent mechanism. We propose that T-type channels play an important role in regulating contractile responses in the microvasculature and, therefore, are a potential therapeutic target.
Cigarette Smoking Abolishes Ischemic Preconditioning-Induced Augmentation of Endothelium-Dependent Vasodilation
Authors: Nakamura Shuji , Kimura Masashi , Goto Chikara , Noma Kensuke , Yoshizumi Masao , Chayama Kazuaki , Kihara Yasuki , Higashi Yukihito
Published: February 2009

We have shown recently that repetition of ischemic preconditioning stimulus augments endothelium-dependent vasodilation in forearm circulation of healthy subjects through increases in NO production and the number of circulating progenitor cells under a local condition. The purpose of this study was to evaluate the “late” effect of ischemic preconditioning on endothelial function in smokers. Ischemic preconditioning was induced by upper-limb ischemia 6 times a day for 1 month. We evaluated forearm blood flow responses to acetylcholine and sodium nitroprusside before and after ischemic preconditioning stimulus in 15 male smokers (27±7 years) and 15 male nonsmokers (26±5 years). Forearm blood flow was measured by using a strain-gauge plethysmography. The ischemic preconditioning stimulus resulted in significant increases in the circulating level of circulating progenitor cells from 1029±261 to 1232±341 mL (
P
=0.02), cell migration response to vascular endothelial growth factor from 38±16 to 52±17 per high-power field (
P
=0.02), and forearm blood flow response to acetylcholine from 25.1±5.2 to 32.4±6.6 mL/min per 100 mL of tissue (
P
=0.002) in nonsmokers, but these did not change in the smoker group. The forearm blood flow responses to sodium nitroprusside before and after the ischemic preconditioning stimulus were similar. Intra-arterial infusion of
N
G
-monomethyl-
l
-arginine, an NO synthase inhibitor, completely eliminated the ischemic preconditioning stimulus-induced augmentation of forearm blood flow responses to acetylcholine in nonsmokers. These findings suggest that repetition of ischemic preconditioning stimulus may be a simple, safe, and feasible therapeutic technique for endothelial protection of peripheral vessels. However, smoking abolishes ischemic preconditioning stimulus-induced augmentation of endothelium-dependent vasodilation.
Arterial Pulse Wave Velocity and Cognition With Advancing Age
Authors: Elias Merrill F. , Robbins Michael A. , Budge Marc M. , Abhayaratna Walter P. , Dore Gregory A. , Elias Penelope K.
Published: February 2009

We hypothesized that carotid-femoral pulse wave velocity (PWV), a marker of arterial stiffness, interacts with age such that the magnitude of associations between PWV and cognitive performance are greater with increasing age and that this interaction is observed despite adjustments for demographic variables, mean arterial pressure, and cardiovascular risk factors. PWV was estimated using applanation tonometry in 409 dementia- and stroke-free participants of the Maine-Syracuse Longitudinal Study (24 to 92 years of age; 62.3% women). Using linear regression analyses in a cross-sectional design, associations between PWV and age and the interaction of PWV and age were examined in relation to a global composite score, the Wechsler Adult Intelligence Scale Similarities test (abstract reasoning), and 4 cognitive domains indexed by multiple cognitive measures. Adjusting for age, gender, education, height, weight, heart rate, mean arterial pressure, and antihypertensive treatment, PWV-by-age interactions were obtained for the global, visual-spatial organization and memory, scanning and tracking, and verbal episodic memory composites, as well as similarities. The combination of higher PWV and age resulted in progressively lower cognitive performance. This finding was the same with an extended model, which also included adjustment for cardiovascular risk factors and other confounds. PWV interacts with age in a multiplicative way to exert a negative influence on cognitive performance level. Early interventions to prevent an increase in arterial stiffness could possibly play an important role in the preservation of cognitive ability.
Depression Is Associated With Decreased Blood Pressure, but Antidepressant Use Increases the Risk for Hypertension
Authors: Licht Carmilla M.M. , de Geus Eco J.C. , Seldenrijk Adrie , van Hout Hein P.J. , Zitman Frans G. , van Dyck Richard , Penninx Brenda W.J.H.
Published: February 2009

The present study compared blood pressure levels between subjects with clinical anxiety and depressive disorders with healthy controls. Cross-sectional data were obtained in a large cohort study, the Netherlands Study of Depression and Anxiety (N=2981). Participants were classified as controls (N=590) or currently or remittedly depressed or anxious subjects (N=2028), of which 1384 were not and 644 were using antidepressants. Regression analyses calculated the contributions of anxiety and depressive disorders and antidepressant use to diastolic and systolic blood pressures, after controlling for multiple covariates. Heart rate and heart rate variability measures were subsequently added to test whether effects of anxiety/depression or medication were mediated by vagal control over the heart. Higher mean diastolic blood pressure was found among the current anxious subjects (β=0.932;
P
=0.03), although anxiety was not significantly related to hypertension risk. Remitted and current depressed subjects had a lower mean systolic blood pressure (β=−1.74,
P=
0.04 and β=−2.35,
P=
0.004, respectively) and were significantly less likely to have isolated systolic hypertension than controls. Users of tricyclic antidepressants had higher mean systolic and diastolic blood pressures and were more likely to have hypertension stage 1 (odds ratio: 1.90; 95% CI: 0.94 to 3.84;
P
=0.07) and stage 2 (odds ratio: 3.19; 95% CI: 1.35 to 7.59;
P
=0.008). Users of noradrenergic and serotonergic working antidepressants were more likely to have hypertension stage 1. This study shows that depressive disorder is associated with low systolic blood pressure and less hypertension, whereas the use of certain antidepressants is associated with both high diastolic and systolic blood pressures and hypertension.
Agent-Based Brain Modeling by Means of Hierarchical Cooperative Coevolution
Authors: Maniadakis Michail , Trahanias Panos
Published: February 2009

We address the development of brain-inspired models that will be embedded in robotic systems to support their cognitive abilities. We introduce a novel agent-based coevolutionary computational framework for modeling assemblies of brain areas. Specifically, self-organized agent structures are employed to represent brain areas. In order to support the design of agents, we introduce a hierarchical cooperative coevolutionary (HCCE) scheme that effectively specifies the structural details of autonomous, yet cooperating system components. The design process is facilitated by the capability of the HCCE-based design mechanism to investigate the performance of the model in lesion conditions. Interestingly, HCCE also provides a consistent mechanism to reconfigure (if necessary) the structure of agents, facilitating follow-up modeling efforts. Implemented models are embedded in a simulated robot to support its behavioral capabilities, also demonstrating the validity of the proposed computational framework.
Comparison of GOES Cloud Classification Algorithms Employing Explicit and Implicit Physics
Authors: Bankert Richard L. , Mitrescu Cristian , Miller Steven D. , Wade Robert H.
Published: February 2009

Cloud-type classification based on multispectral satellite imagery data has been widely researched and demonstrated to be useful for distinguishing a variety of classes using a wide range of methods. The research described here is a comparison of the classifier output from two very different algorithms applied to Geostationary Operational Environmental Satellite (GOES) data over the course of one year. The first algorithm employs spectral channel thresholding and additional physically based tests. The second algorithm was developed through a supervised learning method with characteristic features of expertly labeled image samples used as training data for a 1-nearest-neighbor classification. The latter’s ability to identify classes is also based in physics, but those relationships are embedded implicitly within the algorithm. A pixel-to-pixel comparison analysis was done for hourly daytime scenes within a region in the northeastern Pacific Ocean. Considerable agreement was found in this analysis, with many of the mismatches or disagreements providing insight to the strengths and limitations of each classifier. Depending upon user needs, a rule-based or other postprocessing system that combines the output from the two algorithms could provide the most reliable cloud-type classification.
A Comparison of Oceanic Precipitation Estimates in the Tropics and Subtropics
Authors: Bowman Kenneth P. , Homeyer Cameron R. , Stone Dalon G.
Published: February 2009

A number of Earth remote sensing satellites are currently carrying passive microwave radiometers. A variety of different retrieval algorithms are used to estimate surface rain rates over the ocean from the microwave radiances observed by the radiometers. This study compares several different satellite algorithms with each other and with independent data from rain gauges on ocean buoys. The rain gauge data are from buoys operated by the NOAA Pacific Marine Environmental Laboratory. Potential errors and biases in the gauge data are evaluated. Satellite data are from the Tropical Rainfall Measuring Mission Microwave Imager and from the Special Sensor Microwave Imager instruments on the operational Defense Meteorological Satellite Program F13, F14, and F15 satellites. These data have been processed into rain-rate estimates by the NASA Precipitation Measurement Mission and by Remote Sensing Systems, Inc. Biases between the different datasets are estimated by computing differences between long-term time averages. Most of the satellite datasets agree with each other, and with the gauge data, to within 10% or less. The biases tend to be proportional to the mean rain rate, but the geographical patterns of bias vary depending on the choice of data source and algorithm. Some datasets, however, show biases as large as about 25%, so care should be taken when using these data for climatological studies.
CALIPSO Lidar Calibration Algorithms. Part I: Nighttime 532-nm Parallel Channel and 532-nm Perpendicular Channel
Authors: Powell Kathleen A. , Hostetler Chris A. , Vaughan Mark A. , Lee Kam-Pui , Trepte Charles R. , Rogers Raymond R. , Winker David M. , Liu Zhaoyan , Kuehn Ralph E. , Hunt William H. , Young Stuart A.
Published: February 2009

The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission was launched in April 2006 and has continuously acquired collocated multisensor observations of the spatial and optical properties of clouds and aerosols in the earth’s atmosphere. The primary payload aboard CALIPSO is the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), which makes range-resolved measurements of elastic backscatter at 532 and 1064 nm and linear depolarization ratios at 532 nm. CALIOP measurements are important in reducing uncertainties that currently limit understanding of the global climate system, and it is essential that these measurements be accurately calibrated. This work describes the procedures used to calibrate the 532-nm measurements acquired during the nighttime portions of the CALIPSO orbits. Accurate nighttime calibration of the 532-nm parallel-channel data is fundamental to the success of the CALIOP measurement scheme, because the nighttime calibration is used to infer calibration across the day side of the orbits and all other channels are calibrated relative to the 532-nm parallel channel. The theoretical basis of the molecular normalization technique as applied to space-based lidar measurements is reviewed, and a comprehensive overview of the calibration algorithm implementation is provided. Also included is a description of a data filtering procedure that detects and removes spurious high-energy events that would otherwise introduce large errors into the calibration. Error estimates are derived and comparisons are made to validation data acquired by the NASA airborne high–spectral resolution lidar. Similar analyses are also presented for the 532-nm perpendicular-channel calibration technique.
The Impact of Positive-Definite Moisture Advection and Low-Level Moisture Flux Bias over Orography
Authors: Hahn Robert S. , Mass Clifford F.
Published: February 2009

Overprediction of precipitation has been a frequently noted problem near terrain. Higher model resolution helps simulate sharp microphysical gradients more realistically but can increase spuriously generated moisture in some numerical schemes. The positive-definite moisture advection (PDA) scheme in the Weather Research and Forecasting (WRF) model reduces a significant nonphysical moisture source in the model. This study examines the 13–14 December 2001 second Improvement of Microphysical Parameterization through Observational Verification Experiment (IMPROVE-2) case, in which PDA reduces storm-total precipitation over Oregon by 3%–17%, varying with geographical region, model resolution, and the phase of the storm. The influence of PDA is then analyzed for each hydrometeor species in the Thompson microphysics scheme. Without PDA, the cloud liquid water field generates most of the spurious moisture because of the high frequency of sharp gradients near upwind cloud edges. It is shown that PDA substantially improves precipitation verification and that subtle, but significant, changes occur in the distribution of microphysical species aloft. Finally, another potential source of orographic precipitation error is examined: excessive low-level moisture flux upstream of regional orography.
Voter Turnout in Presidential Democracies
Authors: Dettrey Bryan J. , Schwindt-Bayer Leslie A.
Published: February 2009

Numerous studies indicate that political institutions play an important role in explaining variation in voter turnout across countries. The nuances of institutions unique to presidential elections have been largely overlooked, however, despite the different incentives they offer for voters to participate in elections. This article examines the effect that four presidential institutions had on voter turnout in presidential elections between 1974 and 2004—the timing of elections (whether concurrent or nonconcurrent), the power of the presidency, presidential electoral rules (plurality or majority runoff), and reelection rules. To isolate the effect of presidential institutions, this study controls for other likely influences on turnout, including the economic environment and the wider political context. It finds that (a) runoff elections dampen turnout whereas incumbency spurs it and (b) more powerful presidencies and elections, when held concurrently with legislative elections, have little effect on voter participation.
Articulating identities
Authors: Ybema Sierk , Keenoy Tom , Oswick Cliff , Beverungen Armin , Ellis Nick , Sabelis Ida
Published: February 2009

One symptom of individualism in liquid modernity is the search for `identity'. Using the five theoretically discrete articles in this special issue as both a `rich' discursive resource and a point of departure, we develop a supplementary reading of the narratives which appear to inform identity research. We suggest that, while social agents in pursuit of `identity' draw on a cacophony of discursive sources, it is the varieties of `self—other' talk which emerge as the critical ingredient in processes of identity formation. The dualities that all such self—other talk articulate can be seen as discursive reflections of the more fundamental relationship between the individual and sociality. In turn, this is seen to refract one of the persistent problems of organizational analysis: the agency—structure issue. In addition, while we argue that deploying a discursive perspective to analyze identity work offers distinctive insights, such an approach carries with it an epistemological consequence. For what the articles also indicate is that in any attempt to delineate the `identity of identities', researchers need to be aware of not only the reflexivity displayed by social actors constructing `identity' but also of their own role in `re-authoring' such scripts. We briefly explore the implications of this for identity theory and organizational analysis more generally.
Post-Traumatic Stress in Asylum Seekers and Refugees From Chechnya, Afghanistan, and West Africa: Gender Differences in Symptomatology and Coping
Authors: Renner Walter , Salem Ingrid
Published: February 2009

Background: Internationally, a high number of refugees are in need of help as a consequence of post-traumatic stress or acculturation problems.

Aims: The present study investigated the gender-specific requirements for such interventions taking clinical symptoms as well as coping strategies into account.

Methods: Five psychometric instruments assessing anxiety, depression, posttraumatic stress, somatic symptoms, and social adaptation were administered and semi-structured interviews with n = 150 asylum seekers and refugees from Chechnya, Afghanistan, and West Africa were conducted.

Results: On the level of total test scores, women reported significantly more somatic symptoms than men but there were no further gender differences. On the item level of the questionnaires as well as with respect to the categories obtained from the interview data, marked gender differences were found. Women, as compared to men, reported more somatic symptoms, emotional outbursts, and loss of sexual interest, while men reported detachment. For women, typical coping strategies were concentrating on their children and various indoor activities, while men preferred looking for work and socializing.

Conclusion: Social psychiatric interventions should take gender-specific symptoms and coping strategies into account. For asylum seekers and refugees, same gender client-therapist dyads and groups are highly recommended.
Automatic Syllabification in English: A Comparison of Different Algorithms
Authors: Marchand Yannick , Adsett Connie R. , Damper Robert I.
Published: February 2009

Automatic syllabification of words is challenging, not least because the syllable is not easy to define precisely. Consequently, no accepted standard algorithm for automatic syllabification exists. There are two broad approaches: rule-based and data-driven. The rule-based method effectively embodies some theoretical position regarding the syllable, whereas the data-driven paradigm tries to infer “new” syllabifications from examples assumed to be correctly syllabified already. This article compares the performance of several variants of the two basic approaches. Given the problems of definition, it is difficult to determine a correct syllabification in all cases and so to establish the quality of the “gold standard” corpus used either to evaluate quantitatively the output of an automatic algorithm or as the example-set on which data-driven methods crucially depend. Thus, we look for consensus in the entries in multiple lexical databases of pre-syllabified words. In this work, we have used two independent lexicons, and extracted from them the same 18,016 words with their corresponding (possibly different) syllabifications. We have also created a third lexicon corresponding to the 13,594 words that share the same syllabifications in these two sources. As well as two rule-based approaches (Hammond's and Fisher's implementation of Kahn's), three data-driven techniques are evaluated: a look-up procedure, an exemplar-based generalization technique, and syllabification by analogy (SbA). The results on the three databases show consistent and robust patterns. First, the data-driven techniques outperform the rule-based systems in word and juncture accuracies by a very significant margin but require training data and are slower. Second, syllabification in the pronunciation domain is easier than in the spelling domain. Finally, best results are consistently obtained with SbA.
Japanese Mental Syllabary and Effects of Mora, Syllable, Bi-mora and Word Frequencies on Japanese Speech Production
Authors: Tamaoka Katsuo , Makioka Shogo
Published: February 2009

The present study investigated the existence of a Japanese mental syllabary and units stored therein for speech production. Experiment 1 compared naming latencies between high and low initial mora frequencies using CVCVCV nonwords, indicating that nonwords with a high initial mora frequency were named faster than those with a low frequency initial mora. Experiments 2 and 3 clarified the possibility of CV light and CVN/CVR heavy syllables as being units implicated in speech production. CVNCV nonwords in Experiment 2 and CVRCV nonwords in Experiment 3 displayed shorter naming latencies and lower error rates than their baseline (same bi-mora frequencies) of CVCVCV-structured nonwords. Since bi-mora frequencies between CVN/CVR and CVCV were the same, heavy syllables comprised of CVN and CVR units may contribute to ready-made motor-programs stored in the Japanese mental syllabary as variations of the 100 core light syllables (300 units in total). Experiment 4 further tested the effects of bi-mora frequency on the naming of nonwords, and found that CVCVCV-structured nonwords with high bi-mora frequencies were named more quickly and accurately than those with low bi-mora frequencies, although some bi-mora combinations seem to exhibit nonconforming tendencies (i.e., null significance in item analysis). Experiment 5 demonstrated that the naming of real words with high word frequency was quicker than for other real word conditions with low word frequencies (i.e., word frequency effects), with little effect of bi-mora frequencies. Unlike the nonword condition of Experiment 4, bi-mora frequency had only a minor influence on the naming of real words. Based on these findings, the present study proposes a possible model of the Japanese mental syllabary accompanied by a discussion of bi-mora and word frequency effects.
Independent Effects of Orthographic and Phonological Facilitation on Spoken Word Production in Mandarin
Authors: Qingfang Zhang  , Chen Hsuan-Chih , Stuart Weekes Brendan , Yufang Yang
Published: February 2009

A picture—word interference paradigm with visually presented distractors was used to investigate the independent effects of orthographic and phonological facilitation on Mandarin monosyllabic word production. Both the stimulus-onset asynchrony (SOA) and the picture—word relationship along different lexical dimensions were varied. We observed a pure orthographic facilitation effect and a pure phonological facilitation effect, and found that the patterns of orthographic and phonological facilitation were different. Of most interest, the additive effects of orthographic and phonological facilitation at —150-ms and 0-ms SOAs indicated that the orthographic effect was largely independent of the phonological effect on spoken picture naming. We argue that the present findings are useful for constraining theoretical models of language production and contend that theoretical models of word production need to consider independent effects of orthography and phonology on picture naming, at least in Chinese.
The Item Parameter Replication Method for Detecting Differential Functioning in the Polytomous DFIT Framework
Authors: Raju Nambury S. , Fortmann-Johnson Kristen A. , Kim Wonsuk , Morris Scott B. , Nering Michael L. , Oshima T.C.
Published: February 2009

The recent study of Oshima, Raju, and Nanda proposes the item parameter replication (IPR) method for assessing statistical significance of the noncompensatory differential item functioning (NCDIF) index within the differential functioning of items and tests (DFIT) framework. Previous Monte Carlo simulations have found that the appropriate cutoff values for determining statistical significance of NCDIF depend on sample size and the item response theory (IRT) model used for the analysis. The IPR method simplifies the process of identifying cutoff values that are tailored to a particular research setting. This approach has been shown to be effective for detecting differential item functioning (DIF) in dichotomous items. The current article extends the IPR method to the polytomous case.
Dimension Consistency as an Individual Difference: A New (Old) Perspective on the Assessment Center Construct Validity Debate
Authors: Gibbons Alyssa Mitchell , Rupp Deborah E.
Published: February 2009

This article presents a historical review of how inconsistency in assessment center ratings has been regarded among AC researchers and practitioners, then compares these perspectives to views of inconsistency found in personality psychology. Based on this review, the authors argue for a return to the study of consistency as an individual difference, rather than as simple measurement error. They offer four propositions regarding the inconsistency observed in AC performance, arguing that such inconsistency presents a unique opportunity to identify individuals’ patterns of skill proficiency. Finally, they discuss ways in which differences in consistency are likely to relate to organizational interests, including implications for selection and development.
Taking Stock of What We Know About Mergers and Acquisitions: A Review and Research Agenda
Authors: Haleblian Jerayr , Devers Cynthia E. , McNamara Gerry , Carpenter Mason A. , Davison Robert B.
Published: February 2009

Scholars from multiple fields have shown increasing interest in the causes and consequences of mergers and acquisitions (M&A). Although this proliferation of research has the potential to significantly improve our understanding of M&A activity, absent is the necessary step of consolidating and integrating extant knowledge. Accordingly, this article develops a framework to organize and review recent empirical findings, principally from management, economics, and finance in which interest in acquisition behavior is high but also from other areas that have tangentially explored acquisition activity such as accounting and sociology. This article identifies patterns and theoretical gaps and provides recommendations for future research aimed at developing a more integrated M&A research agenda for management scientists.
Commercialization of the University and Problem Choice by Academic Biological Scientists
Authors: Cooper Mark H.
Published: February 2009

Based on data from a survey of biological scientists at 125 American universities, this article explores how the commercialization of the university affects the problems academic scientists pursue and argues that this reorientation of scientific agendas results in a shift from science in the public interest to science for private goods. Drawing on perspectives from Bourdieu on how actors employ strategic practices toward the accumulation of social capital and acquire dispositional and perceptional tendencies that in turn recondition social structures, the commercialization of the university is construed not as something that ‘‘happens to,’’ but rather something that ‘‘happens through’’ academic scientists. The specific shape and direction of the commercialization of the university is therefore influenced by how scientists incorporate the new resources and social relations of commercialization into their scientific practice and how their creative engagement with shifting structural conditions remakes the culture of academic science.
The non-linear dynamics of meaning processing in social systems
Authors: Leydesdorff Loet
Published: February 2009

Social order cannot be considered as a stable phenomenon because it contains an order of reproduced expectations. When the expectations operate upon one another, they generate a non-linear dynamics that processes meaning. Specific meaning can be stabilized, for example, in social institutions, but all meaning arises from a horizon of possible meanings. Using Luhmann's social systems theory and Rosen's theory of anticipatory systems, I submit equations for modeling the processing of meaning in inter-human communication. First, a self-referential system can use a model of itself for the anticipation. Under the condition of functional differentiation, the social system can be expected to entertain a set of models; each model can also contain a model of the other models. Two anticipatory mechanisms are then possible: one transversal between the models and a longitudinal one providing the modeled systems with meaning from the perspective of hindsight. A system containing two anticipatory mechanisms can become hyper-incursive. Without decision-making, however, a hyper-incursive system would be overloaded with uncertainty. Under this pressure, informed decisions tend to replace the `natural preferences' of agents, and an order of cultural expectations can increasingly be shaped.
Collaborative experiments: Jane Addams, Hull House and experimental social work
Authors: Gross Matthias
Published: February 2009

The social reformer, sociologist and feminist Jane Addams (1860—1935), who established Chicago's Hull House as one of the first settlement houses in America, described her work as experimental, but at the same time she and many of her co-workers rejected the idea of Hull House as a laboratory for social scientific investigation. The present article discusses Addams's unique understanding of social experiment beyond the laboratory. Through `experimental' improvement of social conditions for underserved people and communities in the city of Chicago, Addams and her co-workers perceived the laboratory experiment as an inferior variation of the experiment in society, and not vice versa. Based on the description of experiments at Hull House, this essay attempts to show how different dimensions of experimentation beyond the laboratory can be framed and how alternate phases that combine knowledge production and knowledge application can be conceptually comprised.
Mechanical, Degradation, and Interfacial Properties of Synthetic Degradable Fiber Reinforced Polypropylene Composites
Authors: Khan Ruhul A. , Khan Mubarak A. , Sultana Sabrina , Nuruzzaman Khan M. , Shubhra Quazi T.H. , Noor Farhana G.
Published: February 2009

Polypropylene (PP) matrix synthetic phosphate based degradable fiber reinforced unidirectional composites (10% fiber by weight) were fabricated by compression molding. Tensile strength (TS), tensile modulus (TM), elongation at break (%), bending strength (BS), bending modulus (BM), and impact strength (IS) were found to be 38 MPa, 1.5 GPa, 12%, 44 MPa, 4.9 GPa, and 7.58 kJ/m 2 respectively. Degradation tests of the fibers and composites were performed for six months in aqueous medium at room temperature (25°C). After six months, the mechanical properties of the composites retained almost 80% of their original properties. The interfacial shear strength (IFSS) of the composites were also measured by single fiber fragmentation test (SFFT). The IFSS of the composite system was found 5.9 MPa that indicated good fiber matrix adhesion.
The Impact of Fiber Supplementation on ADMA Levels
Authors: King Dana E. , DeLegge Mark
Published: February 2009

Background: Asymmetric dimethylarginine (ADMA) is an emerging biomarker that has been associated with oxidative metabolism and increased cardiovascular risk. Little information is available regarding the effect of diet on ADMA. Methods: The authors studied 86 overweight/obese adults as part of a clinical trial of psyllium supplementation to determine whether 3 months of such supplementation would affect ADMA levels. Forty‐one people in the intervention group received 14 g/day of psyllium in addition to their usual diet compared with 45 controls who followed their usual diet alone. The 2 groups were comparable at baseline in demographic characteristics and body mass index. Results: Baseline ADMA levels were elevated in this overweight/obese population compared with published reference values in healthy individuals (0.75 vs 0.50 μmol/L). The change in ADMA levels over 3 months was not different in the psyllium group compared with the control group (–.03 vs –.01 μmol/L, P = .73). Conclusions: These findings do not support a significant effect of psyllium fiber supplementation on ADMA.