bluuebunny/crossref_metadata_2025 huggingface dataset:
Inflammation but Not Endothelial Dysfunction Is Associated with the Severity of Coronary Artery Disease in Dyslipidemic Subjects
Authors: Rueda-Clausen Christian F. , López-Jaramillo Patricio , Luengas Carlos , Oubiña Maria del Pilar , Cachofeiro Victoria , Lahera Vicente
Published: June 2009

Introduction. Endothelial dysfunction and inflammation play a key role in the development of atherosclerosis. The present study evaluated endothelial function, inflammatory parameters, and carotid intima-media thickness (IMT) in dyslipidemic patients with or without coronary artery disease (CAD).Methods. Metabolic profile and inflammatory parameters were determined in dyslipidemic patients with (+CAD,n=33) and without (−CAD,n=69) symptomatic CAD. Endothelial function was evaluated by flow mediated dilatation (FMD) and plasma concentration of nitrites and nitrates. Carotid IMT was measured by ultrasound.Results. No significant differences were observed in anthropometric hemodynamic or metabolic parameters between the groups. After adjusting by age and medication usage, some inflammatory markers were significantly higher in +CAD; however no significant differences in FMD or plasma levels of nitrites were observed.Conclusions. In subjects with dyslipidemia, the presence of CAD is associated with an elevation of certain inflammatory markers and carotid IMT but not with further endothelial dysfunction.
Integrated MEMS/NEMS Resonant Cantilevers for Ultrasensitive Biological Detection
Authors: Li Xinxin , Yu Haitao , Gan Xiaohua , Xia Xiaoyuan , Xu Pengcheng , Li Jungang , Liu Min , Li Yongxiang
Published: June 2009

The paper reviews the recent researches implemented in Chinese Academy of Sciences, with achievements on integrated resonant microcantilever sensors. In the resonant cantilevers, the self‐sensing elements and resonance exciting elements are both top‐down integrated with silicon micromachining techniques. Quite a lot of effort is focused on optimization of the resonance mode and sensing structure for improvement of sensitivity. On the other hand, to enable the micro‐cantilevers specifically sensitive to bio/chemical molecules, sensing materials are developed and modified on the cantilever surface with a self‐assembled monolayer (SAM) based bottom‐up construction and surface functionalization. To improve the selectivity of the sensors and depress environmental noise, multiple and localized surface modifications are developed. The achieved volume production capability and satisfactory detecting resolution to trace‐level biological antigen of alpha‐fetoprotein (AFP) give the micro‐cantilever sensors a great promise for rapid and high‐resoluble detection.
Experimental Results on an Integrated GPS and Multisensor System for Land Vehicle Positioning
Authors: Iqbal Umar , Karamat Tashfeen B. , Okou Aime F. , Noureldin Aboelmagd
Published: June 2009

Global position system (GPS) is being widely used in land vehicles to provide positioning information. However, in urban canyons, rural tree canopies, and tunnels, the GPS satellite signal is usually blocked and there is an interruption in the positioning information. To obtain positioning solution during GPS outages, GPS can be augmented with an inertial navigation system (INS). However, the utilization of full inertial measurement unit (IMU) in land vehicles could be quite expensive despite the use of the microelectromechanical system (MEMS)‐based sensors. Contemporary research is focused on reducing the number of inertial sensors inside an IMU. This paper explores a multisensor system (MSS) involving single‐axis gyroscope and an odometer to provide full 2D positioning solution in denied GPS environments. Furthermore, a Kalman filter (KF) model is utilized to predict and compensate the position errors of the proposed MSS. The performance of the proposed method is examined by conducting several road tests trajectories using both MEMS and tactical grade inertial sensors. It was found that by using proposed MSS algorithm, the positional inaccuracies caused by GPS signal blockages are adequately compensated and resulting positional information can be used to steer the land vehicles during GPS outages with relatively small position errors.
Numerical and Experimental Investigation of a Supersonic Flow Field around Solid Fuel on an Inclined Flat Plate
Authors: Hsu Uzu-Kuei
Published: June 2009

This research adopts a shock tube 16 meters long and with a 9 cm bore to create a supersonic, high-temperature, and high-pressure flowfield to observe the gasification and ignition of HTPB solid fuel under different environments. Also, full-scale 3D numerical simulation is executed to enhance the comprehension of this complex phenomenon. The CFD (Computational Fluid Dynamics) code is based on the control volume method and the pre-conditioning method for solving the Navier-Stokes equations to simulate the compressible and incompressible coupling problem. In the tests, a HTPB slab is placed in the windowed-test section. Various test conditions generate different supersonic Mach numbers and environmental temperatures. In addition, the incident angles of the HTPB slab were changed relative to the incoming shock wave. Results show that as the Mach number around the slab section exceeded 1.25, the flowfield temperature achieved 1100 K, which is higher than the HTPB gasification temperature (930 K~1090 K). Then, gasification occurred and a short-period ignition could be observed. In particular, when the slab angle was7∘, the phenomenon became more visible. This is due to the flow field temperature increase when the slab angle was at7∘.
Photonic Crystal Fiber Temperature Sensor Based on Quantum Dot Nanocoatings
Authors: Larrión Beatriz , Hernáez Miguel , Arregui Francisco J. , Goicoechea Javier , Bravo Javier , Matías Ignacio R.
Published: June 2009

Quantum dot nanocoatings have been deposited by means of the Layer‐by‐Layer technique on the inner holes of Photonic Crystal Fibers (PCFs) for the fabrication of temperature sensors. The optical properties of these sensors including absorbance, intensity emission, wavelength of the emission band, and the full width at half maximum (FWHM) have been experimentally studied for a temperature range from −40 to 70 °C.
Corrected Scoliosis, Cholinesterase Deficiency, and Cesarean Section: A Case Report
Authors: Somers Roy , Jacquemyn Yves , Sermeus Luc , Vercauteren Marcel
Published: June 2009

We describe a patient with severe scoliosis for which corrective surgery was performed at the age of 12. During a previous caesarean section under general anaesthesia pseudocholinesterase deficiency was discovered. Ultrasound guided spinal anaesthesia was performed enabling a second caesarean section under loco-regional anaesthesia.
Risk Score for Predicting Outcome in Patients With Asymptomatic Aortic Stenosis
Authors: Monin Jean-Luc , Lancellotti Patrizio , Monchi Mehran , Lim Pascal , Weiss Emmanuel , Piérard Luc , Guéret Pascal
Published: June 2009

Background—

The management of patients with asymptomatic severe aortic stenosis remains controversial. We sought to develop a continuous risk score for predicting the midterm development of symptoms or adverse events in this setting.

Methods and Results—

We prospectively followed 107 patients with asymptomatic aortic stenosis (aged 72 years [63 to 77]; 35 women; aortic-jet velocity, 4.1 m/s [3.5 to 4.4]) at a single center in France. Predefined end points for assessing outcome were the occurrence within 24 months of death or aortic valve replacement necessitated by symptoms or by a positive exercise test. Variables independently associated with outcome were used to build a score that was validated in an independent cohort of 107 patients from Belgium. Independent predictors of outcome were female sex, peak aortic-jet velocity, and B-type natriuretic peptide at baseline. Accordingly, the score could be calculated as follows: Score=[peak velocity (m/s)×2]+(natural logarithm of B-type natriuretic peptide×1.5)+1.5 (if female sex). Event-free survival after 20 months was 80% for patients within the first score quartile compared with only 7% for the fourth quartile. Areas under the receiver operating characteristic curve for the score were 0.90 and 0.89 in the development and validation cohorts, respectively.

Conclusions—

If further validation is achieved, this score may be useful to predict outcome in individual patients with asymptomatic aortic stenosis to select those who might benefit from early surgery.
Inhibition of Prolyl Hydroxylase Domain Proteins Promotes Therapeutic Revascularization
Authors: Loinard Céline , Ginouvès Amandine , Vilar José , Cochain Clément , Zouggari Yasmine , Recalde Alice , Duriez Micheline , Lévy Bernard I. , Pouysségur Jacques , Berra Edurne , Silvestre Jean-Sébastien
Published: June 2009

Background—

The hypoxia-inducible transcription factor (HIF) subunits are destabilized via the O
2
-dependent prolyl hydroxylase domain proteins (PHD1, PHD2, and PHD3). We investigated whether inhibition of PHDs via upregulating HIF might promote postischemic neovascularization.

Methods and Results—

Mice with right femoral artery ligation were treated, by in vivo electrotransfer, with plasmids encoding for an irrelevant short hairpin RNA (shRNA) (shCON [control]) or specific shRNAs directed against HIF-1α (shHIF-1α), PHD1 (shPHD1), PHD2 (shPHD2), and PHD3 (shPHD3). The silencing of PHDs induced a specific and transient downregulation of their respective mRNA and protein levels at day 2 after ischemia and, as expected, upregulated HIF-1α. As a consequence, 2 key hypoxia-inducible proangiogenic actors, vascular endothelial growth factor-A and endothelial nitric oxide synthase, were upregulated at the mRNA and protein levels. In addition, monocyte chemotactic protein-1 mRNA levels and infiltration of Mac-3-positive macrophages were enhanced in ischemic leg of mice treated with shPHD2 and shPHD3. Furthermore, activation of HIF-1α-related pathways was associated with changes in postischemic neovascularization. At day 14, silencing of PHD2 and PHD3 increased vessel density by 2.2- and 2.6-fold, capillary density by 1.8- and 2.1-fold, and foot perfusion by 1.2- and 1.4-fold, respectively, compared with shCON (
P
<0.001). shPHD1 displayed a lower proangiogenic effect. Of interest, coadministration of shHIF-1α with shPHD3 abrogated shPHD3-related effects, suggesting that activation of endogenous HIF-1-dependent pathways mediated the proangiogenic effects of PHD silencing.

Conclusions—

We demonstrated that a direct inhibition of PHDs, and more particularly PHD3, promoted therapeutic revascularization. Furthermore, we showed that activation of the HIF-1 signaling pathway is required to promote this revascularization.
Lipid Treatment Assessment Project 2
Authors: Waters David D. , Brotons Carlos , Chiang Cheng-Wen , Ferrières Jean , Foody JoAnne , Jukema J. Wouter , Santos Raul D. , Verdejo Juan , Messig Michael , McPherson Ruth , Seung Ki-Bae , Tarasenko Lisa
Published: June 2009

Background—

Information about physicians’ adherence to cholesterol management guidelines remains scant. The present survey updates our knowledge of lipid management worldwide.

Methods and Results—

Lipid levels were determined at enrollment in dyslipidemic adult patients on stable lipid-lowering therapy in 9 countries. The primary end point was the success rate, defined as the proportion of patients achieving appropriate low-density lipoprotein cholesterol (LDL-C) goals for their given risk. The mean age of the 9955 evaluable patients was 62±12 years; 54% were male. Coronary disease and diabetes mellitus had been diagnosed in 30% and 31%, respectively, and 14% were current smokers. Current treatment consisted of a statin in 75%. The proportion of patients achieving LDL-C goals according to relevant national guidelines ranged from 47% to 84% across countries. In low-, moderate-, and high-risk groups, mean LDL-C was 119, 109, and 91 mg/dL and mean high-density lipoprotein cholesterol was 62, 49, and 50 mg/dL, respectively. The success rate for LDL-C goal achievement was 86% in low-, 74% in moderate-, and 67% in high-risk patients (73% overall). However, among coronary heart disease patients with ≥2 risk factors, only 30% attained the optional LDL-C goal of <70 mg/dL. In the entire cohort, high-density lipoprotein cholesterol was <40 mg/dL in 19%, 40 to 60 mg/dL in 55%, and >60 mg/dL in 26% of patients.

Conclusions—

Although there is room for improvement, particularly in very-high-risk patients, these results indicate that lipid-lowering therapy is being applied much more successfully than it was a decade ago.
Visually-Guided Balloon Catheter Ablation of Atrial Fibrillation
Authors: Reddy Vivek Y. , Neuzil Petr , Themistoclakis Sakis , Danik Stephan B. , Bonso Aldo , Rossillo Antonio , Raviele Antonio , Schweikert Robert , Ernst Sabine , Kuck Karl-Heinz , Natale Andrea
Published: June 2009

Background—

Electric isolation of the pulmonary veins (PVs) can successfully treat patients with paroxysmal atrial fibrillation. However, it remains technically challenging to identify the left atrial–PV junction and sequentially position the ablation catheter in a point-by-point contiguous fashion to isolate the PVs. In this study, a novel endoscopic ablation system was used to directly visualize and ablate tissue at the left atrial–PV junction with laser energy.

Methods and Results—

This study consisted of 2 phases: a short-term (n=9) and long-term (n=11) canine experimental validation phase and a multicenter clinical feasibility phase (n=30 paroxysmal atrial fibrillation patients). After transseptal puncture, the balloon-based endoscopic ablation system was advanced to each PV ostium, and arcs of laser energy (90° to 360°) were projected onto the target left atrial–PV junction. Electric PV isolation was defined with a circular multielectrode catheter. In the short-term preclinical experimental phase, 15 of 17 targeted PVs (88%) were successfully isolated. Pathological examination revealed well-demarcated circumferential lesions with minimal endothelial disruption. In the long-term experiments, 9 of 10 targeted veins (90%) remained persistently isolated (at 4 to 8 weeks). In the clinical phase, 105 of 116 PVs (91%) were successfully isolated. After a single procedure, the 12-month drug-free rate of freedom from atrial fibrillation was 60% (18 of 30 patients). There were no significant PV stenoses, but adverse events included 1 episode of cardiac tamponade, 1 stroke without residual defect, and 1 asymptomatic phrenic nerve palsy.

Conclusion—

This study establishes the feasibility of a novel paradigm for AF ablation: direct visualization to guide catheter ablation of the left atrial–PV junction.
Amplification of the Pressure Pulse in the Upper Limb in Healthy, Middle-Aged Men and Women
Authors: Segers Patrick , Mahieu Dries , Kips Jan , Rietzschel Ernst , De Buyzere Marc , De Bacquer Dirk , Bekaert Sofie , De Backer Guy , Gillebert Thierry , Verdonck Pascal , Van Bortel Luc
Published: June 2009

Central-to-peripheral amplification of the pressure pulse leads to discrepancies between central and brachial blood pressures. This amplification depends on an individual’s hemodynamic and (patho)physiological characteristics. The aim of this study was to assess the magnitude and correlates of central-to-peripheral amplification in the upper limb in a healthy, middle-aged population (the Asklepios Study). Carotid, brachial, and radial pressure waveforms were acquired noninvasively using applanation tonometry in 1873 subjects (895 women) aged 35 to 55 years. Carotid, brachial, and radial pulse pressures were calculated, as well as the absolute and relative (with carotid pulse pressure as reference) amplifications. With subjects classified per semidecade of age, carotid-to-radial amplification varied from ≈25% in the youngest men to 8% in the oldest women. Amplification was higher in men (20±14%) than in women (13±12%;
P
<0.001) and decreased with age (
P
<0.001) in both. Amplification over the brachial-to-radial path contributed substantially to the total amplification. In univariate analysis, the strongest correlation was found with the carotid augmentation index (−0.51 in women; −0.47 in men; both
P
<0.001). In a multiple linear regression model with carotid-to-radial amplification as the dependent variable, carotid augmentation index, total arterial compliance, and heart rate were identified as the 3 major determinants of upper limb pressure amplification (
R
2
=0.36). We conclude that, in healthy middle-aged subjects, the central-to-radial amplification of the pressure pulse is substantial. Amplification is higher in men than in women, decreases with age, and is primarily associated with the carotid augmentation index.
Impact of Shear Rate Modulation on Vascular Function in Humans
Authors: Tinken Toni M. , Thijssen Dick H.J. , Hopkins Nicola , Black Mark A. , Dawson Ellen A. , Minson Christopher T. , Newcomer Sean C. , Laughlin M. Harold , Cable N. Timothy , Green Daniel J.
Published: June 2009

Shear stress is an important stimulus to arterial adaptation in response to exercise and training in humans. We recently observed significant reverse arterial flow and shear during exercise and different antegrade/retrograde patterns of shear and flow in response to different types of exercise. The purpose of this study was to simultaneously examine flow-mediated dilation, a largely NO-mediated vasodilator response, in both brachial arteries of healthy young men before and after 30-minute interventions consisting of bilateral forearm heating, recumbent leg cycling, and bilateral handgrip exercise. During each intervention, a cuff inflated to 60 mm Hg was placed on 1 arm to unilaterally manipulate the shear rate stimulus. In the noncuffed arm, antegrade flow and shear increased similarly in response to each intervention (ANOVA;
P
<0.001, no interaction between interventions;
P
=0.71). Baseline flow-mediated dilation (4.6%, 6.9%, and 6.7%) increased similarly in response to heating, handgrip, and cycling (8.1%, 10.4%, and 8.9%, ANOVA;
P
<0.001, no interaction;
P
=0.89). In contrast, cuffed arm antegrade shear rate was lower than in the noncuffed arm for all of the conditions (
P
<0.05), and the increase in flow-mediated dilation was abolished in this arm (4.7%, 6.7%, and 6.1%; 2-way ANOVA: all conditions interacted
P
<0.05). These results suggest that differences in the magnitude of antegrade shear rate transduce differences in endothelial vasodilator function in humans, a finding that may have relevance for the impact of different exercise interventions on vascular adaptation in humans.
The Role of Pacific Climate on Low-Frequency Hydroclimatic Variability and Predictability in Southern Alberta, Canada
Authors: Gobena Adam K. , Gan Thian Y.
Published: June 2009

Wavelet and rank correlation analysis were used to identify the links between primary Pacific climate variability modes and low-frequency hydroclimatic variability in the South Saskatchewan River basin (SSRB) of southern Alberta. The April–September average streamflow shows strong interdecadal oscillations with dominant scales of 19–22, 41–42, and 62 yr whereas statistically significant wavelet power in the interannual scale was organized on a background scale of approximately 20–25 yr. At interannual scales, strong coherency is observed between streamflow and the Niño-3 index prior to the 1940s, and in the 1950s, 1970s, and 1980s. However, a change in the phase difference from near 0° in the 1950s to near 180° in the 1980s indicates that the relationship between streamflow and the El Niño–Southern Oscillation (ENSO) is not consistent. Streamflow–Pacific–North America pattern (PNA) and streamflow–Pacific decadal oscillation (PDO) relationships at interannual scales also exhibit similar inconsistencies in phase difference. At interdecadal scales, PDO and streamflow exhibited consistently strong coherence with a stable phase difference of 180° for scales >20 yr. From the period of 1913–2001, the median partial correlation between streamflow and PDO|Niño-3 (read as PDO given Niño-3) was −0.36, whereas it was zero between streamflow and Niño-3|PDO, suggesting that PDO is the primary mode of importance in streamflow variability and predictability in the SSRB. Precipitation variability was also dominated by interdecadal oscillations; however, there is less spatial coherence for dominant scales. Correlations between the basin’s winter precipitation and climate indices are also weaker than with streamflow.
The Description of Mixing in Stratified Layers without Shear in Large-Scale Ocean Models
Authors: Umlauf Lars
Published: June 2009

Large-scale geophysical flows often exhibit layers with negligible vertical shear and infinite gradient Richardson number Ri. It is well known that these layers may be regions of active mixing, even in the absence of local shear production of turbulence because, among other processes, turbulence may be supplied by vertical turbulent transport from neighboring regions. This observation is contrasted by the behavior of most turbulence parameterizations used in ocean climate modeling, predicting the collapse of mixing of mass and matter if the Richardson number exceeds a critical threshold. Here, the performance of a simple model without critical Richardson number is evaluated, taking into account the diffusion of turbulence into layers without shear production and therefore avoiding the suppression of mixing at large values of Ri. The model is based on the framework of second-moment turbulence closures, focusing on the consistent modeling of the turbulent length scale for strongly stratified turbulence. Results are compared to eddy-resolving simulations of stratified shear flows that have recently become available. The model is simple enough for inclusion in ocean climate models.
Energy Flux to a Cyclonic Eddy off Cabo Frio, Brazil
Authors: Mano Manlio F. , Paiva Afonso M. , Torres Audalio R. , Coutinho Alvaro L. G. A.
Published: June 2009

To evaluate the energy flux from the mean flow of South Atlantic western boundary currents toward typical Cabo Frio eddies (at Brazilian southeast coast), the southwestern Atlantic circulation was simulated with the Princeton Ocean Model. Throughout the study period, the vertical profile of eddy available potential energy direction was monitored.

The results indicated that baroclinic instability eddies first appear in intermediate depths and then its signal propagates upward, draining energy from the Brazil Current (BC), until it reaches the surface, 30 days after its formation. The depth of eddy formation is related to the vertical profile of the mean potential vorticity cross-current gradient (∂q/∂s). The beginning of the potential energy flux toward the perturbation and the origin of the eddy occurred at a similar depth and time.

The observed pattern suggests the following cycle: 1) a well-defined southwestward-flowing BC in the beginning of the period, with a baroclinically unstable profile of ∂q/∂s; 2) energy flux from the mean flow toward perturbation at intermediate depth; 3) current destabilization and meandering; 4) formation and growth of the cyclonic eddy; 5) potential energy flux progressively shallower; 6) propagation of the eddy signal upward; and 7) stabilization of the water column.
Wind-Driven Ageostrophic Transport in the North Equatorial Countercurrent of the Eastern Pacific at 95°W
Authors: Sprintall Janet , Kennan Sean , Kim Yoo Yin , Niiler Peter
Published: June 2009

Observations of horizontal velocity from two shipboard acoustic Doppler current profilers (ADCPs), as well as wind, temperature, and salinity observations from a cruise during June–July 2001, are used to compute a simplified mean meridional momentum balance of the North Equatorial Countercurrent (NECC) at 95°W. The terms that are retained in the momentum balance and derived using the measurements are the Coriolis and pressure gradient forces, and the vertical divergence of the turbulent stress. All terms were vertically integrated over the surface turbulent layer. The K-profile parameterization (KPP) prescribed Richardson number (Ri) is used to determine the depth of the turbulent boundary layer h at which the turbulent stress and its gradient vanish. At the time of the cruise, surface drifters and altimeter data show the flow structure of the NECC was complicated by the presence of tropical instability waves to the south and a strong Costa Rica Dome to the north. Nonetheless, a consistent, simplified momentum balance for the surface layer was achieved from the time mean of 19 days of repeat transects along 95°W with a 0.5° latitude resolution. The best agreement between the ageostrophic transport determined from the near-surface cruise measurements and the wind-derived Ekman transport was obtained for an Ri of 0.23 ± 0.05. The corresponding h ranges from ∼55 m at 4°N to ∼30 m within the NECC core (4.5°–6°N) and shoaling to just 15 m at 7°N. In general, the mean ageostrophic and Ekman transports decreased from south to north along the 95°W transect, although within the core of the NECC both transports were relatively strong and steady. This study underscores the importance of the southerly wind-driven eastward Ekman transport in the turbulent boundary layer before the NECC becomes fully developed later in the year through indirect forcing from the wind stress curl.
Characterizing Thermohaline Intrusions in the North Pacific Subtropical Frontal Zone
Authors: Shcherbina Andrey Y. , Gregg Michael C. , Alford Matthew H. , Harcourt Ramsey R.
Published: June 2009

A monthlong field survey in July 2007, focused on the North Pacific subtropical frontal zone (STFZ) near 30°N, 158°W, combined towed depth-cycling conductivity–temperature–depth (CTD) profiling with shipboard current observations. Measurements were used to investigate the distribution and structure of thermohaline intrusions. The study revealed that local extrema of vertical salinity profiles, often used as intrusion indicators, were only a subset of a wider class of distortions in thermohaline fields due to interleaving processes. A new method to investigate interleaving based on diapycnal spiciness curvature was used to describe an expanded class of laterally coherent intrusions. STFZ intrusions were characterized by their overall statistics and by a number of case studies. Thermohaline interleaving was particularly intense within 5 km of two partially compensated fronts, where intrusions with both positive and negative salinity anomalies were widespread. The vertical and cross-frontal scales of the intrusions were on the order of 10 m and 5 km, respectively. Though highly variable, the slopes of these features were typically intermediate between those of isopycnals and isohalines. Although the influence of double-diffusive processes sometime during the evolution of intrusions could not be excluded, the broad spectrum of the observed features suggests that any role of double diffusion was secondary.
Assimilation of AIRS Radiances Affected by Mid- to Low-Level Clouds
Authors: Pangaud Thomas , Fourrie Nadia , Guidard Vincent , Dahoui Mohamed , Rabier Florence
Published: June 2009

An approach to make use of Atmospheric Infrared Sounder (AIRS) cloud-affected infrared radiances has been developed at Météo-France in the context of the global numerical weather prediction model. The method is based on (i) the detection and the characterization of clouds by the CO2-slicing algorithm and (ii) the identification of clear–cloudy channels using the ECMWF cloud-detection scheme. Once a hypothetical cloud-affected pixel is detected by the CO2-slicing scheme, the cloud-top pressure and the effective cloud fraction are provided to the radiative transfer model simultaneously with other atmospheric variables to simulate cloud-affected radiances. Furthermore, the ECMWF scheme flags each channel of the pixel as clear or cloudy. In the current configuration of the assimilation scheme, channels affected by clouds whose cloud-top pressure ranges between 600 and 950 hPa are assimilated over sea in addition to clear channels. Results of assimilation experiments are presented. On average, 3.5% of additional pixels are assimilated over the globe but additional assimilated channels are much more numerous for mid- to high latitudes (10% of additional assimilated channels on average). Encouraging results are found in the quality of the analyses: background departures of AIRS observations are reduced, especially for surface channels, which are globally 4 times smaller, and the analysis better fits some conventional and satellite data. Global forecasts are slightly improved for the geopotential field. These improvements are significant up to the 72-h forecast range. Predictability improvements have been obtained for a case study: a low pressure system that affected the southeastern part of Italy in September 2006. The trajectory, intensity, and the whole development of the cyclogenesis are better predicted, whatever the forecast range, for this case study.
Planetary Waves, Cyclogenesis, and the Irregular Breakdown of Zonal Motion over the North Atlantic
Authors: Roebber Paul J.
Published: June 2009

Numerous observational and modeling studies have suggested the importance of cyclogenesis to the breakdown of the zonal flow and the maintenance of atmospheric blocks, whereas other studies have shown that low-frequency dynamics are sufficient to produce and maintain these patterns. Experiments with a simple model of the general circulation and empirical evidence obtained from reanalysis and cyclone tracking data are used to develop a conceptual understanding of this irregular response. The model’s results and observational data are consistent with the idea that the North Atlantic flow response to cyclone forcing is preconditioned by the state of the hemispheric circulation. A characteristic hemispheric flow configuration reminiscent of the shedding of a potential vorticity (PV) filament and tightening of the PV gradient is particularly responsive to cyclogenesis, with the likelihood of below 10th percentile North Atlantic zonal flow under these conditions increased by a factor of 2.37 for each cyclone event. A second characteristic pattern, reminiscent of the PV wave-breaking anticyclonic roll up, responds in an opposite way to cyclogenesis, with a decrease in the likelihood of below 10th percentile zonal flow by a factor of 0.67. This perspective is connected to the decades of research on blocking and opens an opportunity for the development of medium-range forecast model postprocessors that might provide probabilistic forecasts of North Atlantic flow transitions.
CORRIGENDUM: False Alarm Rate or False Alarm Ratio?
Authors: Barnes Lindsey R. , Schultz David M. , Gruntfest Eve C. , Hayden Mary H. , Benight Charles C.
Published: June 2009

Two items need to be clarified from an earlier work of the authors. The first is that the layout of the 2 × 2 contingency table was reversed from standard practice, with the titles of “observed event” and “forecast” transposed. The second is that FAR should have represented “false alarm ratio,” not “false alarm rate.” Unfortunately, the terminology used in the atmospheric sciences is confusing, with authors as early as 1965 having used the terminology differently from currently accepted practice. More recent studies are not much better. A survey of peer-reviewed articles published in American Meteorological Society journals between 2001 and 2007 found that, of 26 articles using those terms, 10 (38%) used them inconsistently with the currently accepted definitions. This article recommends that authors make explicit how their verification statistics are calculated in their manuscripts and consider using the terms probability of false detection and probability of false alarm instead of false alarm rate and false alarm ratio.
Using Computational Cognitive Modeling to Predict Dual-Task Performance With Sleep Deprivation
Authors: Gunzelmann Glenn , Byrne Michael D. , Gluck Kevin A. , Moore L. Richard
Published: June 2009

Objective: The effects of fatigue on multiple-task performance were explored through computational cognitive modeling. Background: Fatigue typically has a negative impact on human performance. Biomathematical models exist that characterize the dynamics of human alertness, but the link between alertness and in situ performance on specific tasks is tenuous. Cognitive architectures offer a principled means of establishing that link. Method: We implemented mechanisms for fatigue, which produce microlapses in cognitive processing, into an existing model, adaptive control of thought—rational, and validated the performance predictions with Bratzke, Rolke, Ulrich, and Peters' data on fatigue and multiple-task performance. Results: The microlapse model replicated the human performance results very well with zero free parameters, although the fit was improved when we allowed two individual differences parameters to vary. Conclusion: Increased frequency of microlapses as a result of fatigue provides a parsimonious explanation for the impact of fatigue on dual-task performance and is consistent with previous research. Application: Our results illustrate how using biomathematical models of fatigue in conjunction with a cognitive architecture can result in accurate predictions of the effects of fatigue on dual-task performance. Extending and generalizing this capability has potential utility in any safety-critical domain in which fatigue may affect performance.
Tactile Elevation Perception in Blind and Sighted Participants and Its Implications for Tactile Map Creation
Authors: Jehoel Sandra , Sowden Paul T. , Ungar Simon , Sterr Annette
Published: June 2009

Objective: Our goal was to determine the optimal elevation of tactile map symbols. Background: Tactile perception research predicts that symbol elevation (vertical height) and texture on tactile maps could influence their readability. However, although research has shown that elevation influences detection and discrimination thresholds for single tactile stimuli and that the physiological response of fingertip receptors varies with texture, little is known about the influence of these parameters on the identification of stimuli in the context of multiple symbols as found on tactile maps. Method: Sighted and visually impaired participants performed tactile symbol identification tasks. In Experiment 1, we measured the effect of elevation on identification accuracy. In Experiment 2, we measured the effect of elevation and symbol texture on identification speed. Results: Symbol elevation influenced both speed and accuracy of identification; thresholds were higher than those found in work on detection and discrimination but lower than on existing tactile maps. Furthermore, as predicted from existing knowledge of tactile perception, rough features were identified more quickly than smooth ones. Finally, visually impaired participants performed better than sighted ones. Conclusion: The symbol elevations necessary for identification (0.040 to 0.080 mm) are considerably lower than would be expected on the basis of existing tactile maps (generally 0.5 mm or higher) and design guidelines (0.4 mm). Application: Tactile map production costs could be reduced and map durability increased by reducing symbol elevation. Furthermore, legibility of maps could be improved by using rough features, which are read more easily, and smaller symbols, which reduce crowding of graphics.
Do Familiar Teammates Request and Accept More Backup? Transactive Memory in Air Traffic Control
Authors: Smith-Jentsch Kimberly A. , Kraiger Kurt , Cannon-Bowers Janis A. , Salas Eduardo
Published: June 2009

Objective: The present study investigated factors that explain when and why different groups of teammates are more likely to request and accept backup from one another when needed in an environment characterized by extreme time pressure and severe consequences of error: commercial air traffic control (ATC). Background: Transactive memory theory states that teammates develop consensus regarding the distribution of their relative expertise as well as confidence in that expertise over time and that this facilitates coordination processes. The present study investigated whether this theory could help to explain between-team differences in requesting and accepting backup when needed. Method: The present study used cross-sectional data collected from 51 commercial ATC teams. Hypotheses were tested using multiple regression analysis. Results: Teammates with greater experience working together requested and accepted backup from one another more than those with lesser experience working together. Teammate knowledge consensus and perceived team efficacy appear to have mediated this relationship. Conclusion: Transactive memory theory extends to high-stress environments in which members' expertise is highly overlapping. Teammates' shared mental models about one another increase the likelihood that they will request and accept backup. Application: Teammate familiarity should be considered when choosing among potential replacement team members. Training strategies that accelerate the development of teammate knowledge consensus and team efficacy are warranted.
Repeatability, Reproducibility, and Validity of a New Method for Characterizing Lumbar Support in Automotive Seating
Authors: Kolich Mike
Published: June 2009

Objective: This article describes a new and more repeatable, reproducible, and valid test method for characterizing lumbar support in automotive seating. Background: Lumbar support is important because it affects occupant accommodation and perceptions of seat comfort. Assessing only the lumbar mechanism—particularly in terms of travel—is inadequate because it does not consider the effects of trim and foam. Method: The Society of Automotive Engineers' next-generation H-Point machine and associated loading protocol were used as the basis for the new test. Results: The method was found to satisfy minimum gage repeatability and reproducibility requirements. Validity was demonstrated through a regression model that revealed 93.9% of the variance in subjective ratings of poor uncomfortable lumbar support can be explained by two objective indicators: (1) lumbar support prominence in the full-off position and (2) effective travel. Conclusion: The method can be used to differentiate between seats offering two-way adjustable lumbar support. The best two-way adjustable lumbar seat systems are those that couple little to no lumbar support in the starting or off position (i.e., they are nonintrusive) with a considerable amount of effective or perceptible travel. Application: The automotive industry has long needed a way to address the fact that consumers want more lumbar support than their seats currently supply. This contribution offers a method to objectify an important aspect of automotive seating comfort—namely, lumbar support. This should help human factors professionals produce, but not necessarily guarantee, better consumer ratings.
Simple Displays of Talker Location Improve Voice Identification Performance in Multitalker, Spatialized Audio Environments
Authors: Kilgore Ryan M.
Published: June 2009

Objective: The aim of this study was to assess the voice identification benefits of visual depictions of the relative locations of spatialized talkers in a serial listening task. Background: Although spatialized audio is known to improve speech intelligibility and voice identification accuracy within multitalker environments, prior studies have not found any additional benefit for augmenting spatialized audio with visual depictions of relative voice locations. These studies, however, were restricted to small audio environments (four voices), potentially limiting the ability of simple talker location displays to provide additional identification benefit. Method: In the first experiment, 18 participants performed a voice identification task for four- and eight-voice environments under three display conditions: (a) nonspatialized voices with an audio-only display, (b) spatialized voices with an audio-only display, and (c) spatialized voices augmented by a visual display of relative talker locations. In the second experiment, 32 participants performed the same voice identification task within a spatialized eight-voice environment but with audio and visual displays of differing angular scale. Results: Visually depicting relative talker locations improved voice identification performance in terms of both accuracy and response time, particularly for more populous auditory spaces. Both auditory and visual display scale affected these benefits, with large-angle displays performing the best for both modalities. Conclusion: Results indicate that simple visual representations of spatialized audio environments help listeners identify voices and that these representations are more effective when the angular spacing (auditory and visual) between talker locations is increased. Application: These results have important implications for the design and implementation of collaborative audio environments for shared, desktop, and portable communication devices.
Skill Acquisition While Operating In-Vehicle Information Systems: Interface Design Determines the Level of Safety-Relevant Distractions
Authors: Jahn Georg , Krems Josef F. , Gelau Christhard
Published: June 2009

Objective: This study tested whether the ease of learning to use human—machine interfaces of in-vehicle information systems (IVIS) can be assessed at standstill. Background: Assessing the attentional demand of IVIS should include an evaluation of ease of learning, because the use of IVIS at low skill levels may create safety-relevant distractions. Method: Skill acquisition in operating IVIS was quantified by fitting the power law of practice to training data sets collected in a driving study and at standstill. Participants practiced manual destination entry with two route guidance systems differing in cognitive demand. In Experiment 1, a sample of middle-aged participants was trained while steering routes of varying driving demands. In Experiment 2, another sample of middle-aged participants was trained at standstill. Results: In Experiment 1, display glance times were less affected by driving demands than by total task times and decreased at slightly higher speed-up rates (0.02 higher on average) than task times collected at standstill in Experiment 2. The system interface that minimized cognitive demand was operated more quickly and was easier to learn. Its system delays increased static task times, which still predicted 58% of variance in display glance times compared with even 76% for the second system. Conclusion: The ease of learning to use an IVIS interface and the decrease in attentional demand with training can be assessed at standstill. Application: Fitting the power law of practice to static task times yields parameters that predict display glance times while driving, which makes it possible to compare interfaces with regard to ease of learning.
How Accurate Is Information Transmitted to Medical Professionals Joining a Medical Emergency? A Simulator Study
Authors: Bogenstätter Yvonne , Tschan Franziska , Semmer Norbert K. , Spychiger Martin , Breuer Marc , Marsch Stephan
Published: June 2009

Objective: This study used a high-fidelity simulation to examine factors influencing the accuracy of 201 pieces of information transmitted to nurses and physicians joining a medical emergency situation. Background: Inaccurate or incomplete information transmission has been identified as a major problem in medicine. However, only a few studies have assessed possible causes of transmission errors. Method: Each of 20 groups was composed of two or three nurses (first responders), one resident joining the group later, and one senior doctor joining last. Groups treated a patient suffering a cardiac arrest. Results: Multilevel binomial analyses showed that 18% of the information given to newcomers was inaccurate. Quantitative information requiring repeated updating was particularly error prone. Information generated earlier (i.e., older information) was more likely to be transmitted inaccurately. Explicitly encoding information to be transmitted after the physicians arrived at the scene enhanced accuracy, supporting transfer-appropriate processing theory. Conclusion: Information transmitted to nurses and physicians who join an ongoing emergency is only partly reliable. Therefore, medical professionals should not take accuracy for granted and should be aware of the nature of transmission errors. Application: Medical professionals should be trained in adequate encoding of information and in standardized communication procedures with regard to error-prone information. In addition, technical devices should be implemented that reduce reliance on memory regarding information with error-prone characteristics.
An Investigation of Driver Distraction Near the Tipping Point of Traffic Flow Stability
Authors: Cooper Joel M. , Vladisavljevic Ivana , Medeiros-Ward Nathan , Martin Peter T. , Strayer David L.
Published: June 2009

Objective: The purpose of this study was to explore the interrelationship between driver distraction and characteristics of driver behavior associated with reduced highway traffic efficiency. Background: Research on the three-phase traffic theory and on behavioral driving suggests that a number of characteristics associated with efficient traffic flow may be affected by driver distraction. Previous studies have been limited, however, by the fact that researchers typically do not allow participants to change lanes, nor do they account for the impact of varying traffic states on driving performance. Methods: Participants drove in three simulated environments with differing traffic congestion while both using and not using a cell phone. Instructed only to obey the speed limit, participants were allowed to vary driving behaviors, such as those involving forward following distance, speed, and lane-changing frequency. Results: Both driver distraction and traffic congestion were found to significantly affect lane change frequency, mean speed, and the likelihood of remaining behind a slower-moving lead vehicle. Conclusions: This research suggests that the behavioral profile of “cell phone drivers,” which is often described as compensatory, may have far-reaching and unexpected consequences for traffic efficiency. Application: By considering the dynamic interplay between characteristics of traffic flow and driver behavior, this research may inform both public policy regarding in-vehicle cell phone use and future investigations of driving behavior.
Goal Integration and Well-Being
Authors: van Dierendonck Dirk , Rodríguez-Carvajal Raquel , Moreno-Jiménez Bernardo , Dijkstra Maria T. M.
Published: June 2009

Personality integration has been related to individual well-being. The present study focused on the combined influence of personality integration through the personal-striving goal construct, active-passive approach toward achieving one’s goals, and inner resources on well-being. Specific attention was given to how this process works out in two culturally different countries: the Netherlands and Spain. Results indicated that goal integration, passive thinking, active thinking, and vitality were higher in the Netherlands compared to Spain. It was also shown that inner resources combined with active thinking to function as a buffer for the possible negative effects on vitality. Results were similar in both countries, a finding that provides an indication for possible cross-cultural generalization of this process. The overall results present active-passive thinking combined with inner resources as an influential factor in the relation between goal integration and well-being.