bluuebunny/crossref_metadata_2025 huggingface dataset:
Biomechanical Forces in Atherosclerosis-Resistant Vascular Regions Regulate Endothelial Redox Balance via Phosphoinositol 3-Kinase/Akt-Dependent Activation of Nrf2
Authors: Dai Guohao , Vaughn Saran , Zhang Yuzhi , Wang Eric T. , Garcia-Cardena Guillermo , Gimbrone Michael A.
Published: August 2007

Local patterns of biomechanical forces experienced by endothelial cells (ECs) in different vascular geometries appear to play an essential role in regulating EC function and determining the regional susceptibility to atherosclerosis, even in the face of systemic risk factors. To study how biomechanical forces regulate EC redox homeostasis, an important pathogenic factor in atherogenesis, we have cultured human ECs under 2 prototypic arterial shear stress waveforms, “atheroprone” and “atheroprotective,” which were derived from 2 distinct vascular regions in vivo that are typically “susceptible” or “resistant” to atherosclerosis. We demonstrate that atheroprotective flow decreases EC intracellular redox level and protects ECs against oxidative stress–induced injury. To identify the molecular mechanisms that control this cellular response, we examined several major oxidative/antioxidative pathways and found that atheroprotective flow upregulated certain antioxidant genes and strongly activated the transcription factor Nrf2. Using a strategy of small interfering RNA inhibition of Nrf2 expression combined with genome-wide transcriptional profiling, we determined the downstream targets of Nrf2 activation and identified Nrf2 as a critical determinant for the changes in endothelial redox balance exerted by atheroprotective flow. In addition, we showed that atheroprotective flow activates Nrf2 via the phosphoinositol 3-kinase/Akt pathway, and this activation occurs differentially in atherosclerosis-resistant and atherosclerosis-susceptible regions of the mouse aorta. Taken together, our data demonstrate that hemodynamic forces present in atherosclerosis-resistant and -susceptible regions of the vasculature differentially regulate EC redox state and antioxidant potential. These alterations in redox homeostasis are primarily the result of the phosphoinositol 3-kinase/Akt-dependent activation of Nrf2 and its downstream transcriptional targets.
cGMP-Dependent Relaxation of Smooth Muscle Is Coupled With the Change in the Phosphorylation of Myosin Phosphatase
Authors: Nakamura Kensei , Koga Yasuhiko , Sakai Hiroyasu , Homma Kazuaki , Ikebe Mitsuo
Published: August 2007

Nitric oxide/cGMP pathway induces vasodilatation, yet the underlying mechanism is obscure. In the present study, we studied the mechanism of cGMP-induced relaxation of the smooth muscle contractile apparatus using permeabilized rabbit femoral arterial smooth muscle. 8-Br-cGMP–induced relaxation was accompanied with a decrease in myosin light chain (MLC) phosphorylation. MLC phosphatase (MLCP) activity, once decreased by agonist-stimulation, recovered to the resting level on addition of 8-Br-cGMP. Because MLCP activity is regulated by the phosphorylation of a MLCP-specific inhibitor, CPI17 at Thr38 and MBS (myosin binding subunit of MLCP) at Thr696, we examined the effect of 8-Br-cGMP on the phosphorylation of these MLCP modulators. Whereas CPI17 phosphorylation was unchanged after addition of 8-Br-cGMP, MBS phosphorylation at Thr696 was significantly decreased by 8-Br-cGMP. We found that 8-Br-cGMP markedly increased MBS phosphorylation at Ser695 in the fiber pretreated with phenylephrine. MBS phosphorylation of Thr696 phosphorylated MBS at Ser695 partially resumed MLCP activity inhibited by Thr696 phosphorylation. Whereas Ser695 phosphorylation was markedly increased, the extent of diphosphorylated MBS at Ser695 and Thr696 in fibers was unchanged after cGMP-stimulation. We found that MBS phosphatase activity in arteries for both diphosphorylated MBS and monophosphorylated MBS at Thr696 significantly increased by 8-Br-cGMP, whereas MBS kinase activity was unchanged. These results suggest that the phosphorylation at Ser640 induced by cGMP shifted the equilibrium of the Thr641 phosphorylation toward dephosphorylation, thus increasing MLCP activity. This results in the decrease in MLC phosphorylation and smooth muscle relaxation.
Isoform-Specific Regulation by
N
G
,
N
G
-Dimethylarginine Dimethylaminohydrolase of Rat Serum Asymmetric Dimethylarginine and Vascular Endothelium-Derived Relaxing Factor/NO
Authors: Wang Dan , Gill Pritmohinder S. , Chabrashvili Tinatin , Onozato Maristela L. , Raggio Julie , Mendonca Margarida , Dennehy Kathryn , Li Min , Modlinger Paul , Leiper James , Vallance Patrick , Adler Oscar , Leone Anna , Tojo Akihiro , Welch William J. , Wilcox Christopher S.
Published: August 2007

Asymmetric dimethylarginine (ADMA), which inhibits NO synthase, is inactivated by
N
G
,
N
G
-dimethylarginine dimethylaminohydrolase (DDAH). We tested whether DDAH-1 or -2 regulates serum ADMA (S
ADMA
) and/or endothelium-derived relaxing factor (EDRF)/NO. Small inhibitory (si)RNAs targeting DDAH-1 or -2, or an siRNA control were given intravenously to rats. After 72 hours, EDRF/NO was assessed from acetylcholine-induced, NO synthase–dependent relaxation and 4-amino-5-methylamino-2′,7′-diflouroflourescein diacetate for NO activity in isolated mesenteric resistance vessels (MRVs). Expression of mRNA for DDAH-1 versus -2 was 2- and 7-fold higher in the kidney cortex and liver, respectively, whereas expression of DDAH-2 versus -1 was 5-fold higher in MRVs. The proteins and mRNAs for DDAH-1 or -2 were reduced selectively by 35% to 85% in the kidney cortex, liver, and MRVs 72 hours following the corresponding siRNA. S
ADMA
was increased only after siDDAH-1 (266±25 versus 342±39 [mean±SD] nmol · L
−1
;
P
<0.005), whereas EDRF/NO responses and NO activity were not changed consistently by siDDAH-1 but were greatly reduced after siDDAH-2. Mean arterial pressure was not changed significantly by any siRNA. In conclusion, S
ADMA
is regulated by DDAH-1, which is expressed at sites of ADMA metabolism in the kidney cortex and liver, whereas EDRF/NO is regulated primarily by DDAH-2, which is expressed strongly in blood vessels. This implies specific functions of DDAH isoforms.
A Regional System to Provide Timely Access to Percutaneous Coronary Intervention for ST-Elevation Myocardial Infarction
Authors: Henry Timothy D. , Sharkey Scott W. , Burke M. Nicholas , Chavez Ivan J. , Graham Kevin J. , Henry Christopher R. , Lips Daniel L. , Madison James D. , Menssen Katie M. , Mooney Michael R. , Newell Marc C. , Pedersen Wes R. , Poulose Anil K. , Traverse Jay H. , Unger Barbara T. , Wang Yale L. , Larson David M.
Published: August 2007

Background—

Percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) is superior to fibrinolysis when performed in a timely manner in high-volume centers. Recent European trials suggest that transfer for PCI also may be superior to fibrinolysis and increase access to PCI. In the United States, transfer times are consistently long; therefore, many believe a transfer for PCI strategy for STEMI is not practical.

Methods and Results—

We developed a standardized PCI-based treatment system for STEMI patients from 30 hospitals up to 210 miles from a PCI center. From March 2003 to November 2006, 1345 consecutive STEMI patients were treated, including 1048 patients transferred from non-PCI hospitals. The median first door-to-balloon time for patients <60 miles (zone 1) and 60 to 210 miles (zone 2) from the PCI center was 95 minutes (25th and 75th percentiles, 82 and 116 minutes) and 120 minutes (25th and 75th percentiles, 100 and 145 minutes), respectively. Despite the high-risk unselected patient population (cardiogenic shock, 12.3%; cardiac arrest, 10.8%; and elderly [≥80 years of age], 14.6%), in-hospital mortality was 4.2%, and median length of stay was 3 days.

Conclusions—

Rapid transfer of STEMI patients from community hospitals up to 210 miles from a PCI center is safe and feasible using a standardized protocol with an integrated transfer system.
Can Patients at Elevated Risk of Stroke Treated With Anticoagulants Be Further Risk Stratified?
Authors: Baruch Lawrence , Gage Brian F. , Horrow Jay , Juul-Möller Steen , Labovitz Arthur , Persson Maria , Zabalgoitia Miguel
Published: August 2007

Background and Purpose—

Patients with atrial fibrillation have a varied risk of stroke, depending on age and comorbid conditions. The objective of this study was to assess the predictive value of stroke risk classification schemes and to identify patients with atrial fibrillation who are at substantial risk of stroke despite optimal anticoagulant therapy.

Methods—

Seven recognized classification schemes—the American College of Chest Physicians 2001, American College of Chest Physicians 2004, Stroke Prevention in Atrial Fibrillation (SPAF), Atrial Fibrillation Investigators, Framingham, van Walraven, and CHADS
2
—were compared for their ability to predict ischemic stroke in patients receiving anticoagulant therapy. Data came from the Stroke Prevention using an ORal Thrombin Inhibitor in atrial Fibrillation III and V trials, which compared the efficacy of adjusted-dose warfarin and the direct thrombin inhibitor ximelagatran (36 mg twice daily) in preventing thromboembolic events in 7329 patients with chronic or paroxysmal nonvalvular atrial fibrillation who were at moderate or high risk of ischemic stroke. The main outcome measure was ischemic stroke, as determined by a central event adjudication committee.

Results—

During 11 245 patient-years of follow-up, 159 patients had an ischemic stroke (1.4%/year). As indicated by
c
statistics and hazard ratios, 3 of the classification schemes predicted stroke significantly better than chance: Framingham (
c
=0.64), CHADS
2
(
c
=0.65), and SPAF (
c
=0.61).

Conclusions—

In a large cohort of atrial fibrillation patients at moderate or high risk of ischemic stroke treated with warfarin or ximelagatran, the CHADS
2
, SPAF, and Framingham schemes had greater predictive accuracy than chance. This predictive ability may allow clinicians to target high-risk patients for more aggressive intervention.
Elevated Serum S100B Levels Indicate a Higher Risk of Hemorrhagic Transformation After Thrombolytic Therapy in Acute Stroke
Authors: Foerch Christian , Wunderlich Michael T. , Dvorak Florian , Humpich Marek , Kahles Timo , Goertler Michael , Alvarez-Sabín Jose , Wallesch Claus W. , Molina Carlos A. , Steinmetz Helmuth , Sitzer Matthias , Montaner Joan
Published: August 2007

Background and Purpose—

Intracerebral hemorrhage constitutes an often fatal sequela of thrombolytic therapy in patients with ischemic stroke. Early blood–brain barrier disruption may play an important role, and the astroglial protein S100B is known to indicate blood–brain barrier dysfunction. We investigated whether elevated pretreatment serum S100B levels predict hemorrhagic transformation (HT) in thrombolyzed patients with stroke.

Methods—

We retrospectively included 275 patients with ischemic stroke (mean age of 69±13 years; 46% female) who had received thrombolytic therapy within 6 hours of symptom onset. S100B levels were determined from pretreatment blood samples. Follow-up brain scans were obtained 24 hours after admission, and HT was classified as either hemorrhagic infarction (1, 2) or parenchymal hemorrhage (1, 2).

Results—

HT occurred in 80 patients (29%; 45 hemorrhagic infarction, 35 parenchymal hemorrhage). Median S100B values were significantly higher in patients with HT (0.14 versus 0.11 μg/L;
P
=0.017). An S100B value in the highest quintile corresponded to an OR for any HT of 2.87 (95% CI: 1.55 to 5.32;
P
=0.001) in univariate analysis and of 2.80 (1.40 to 5.62;
P
=0.004) after adjustment for age, sex, symptom severity, timespan from symptom onset to hospital admission, vascular risk factors, and storage time of serum probes. A pretreatment S100B value above 0.23 μg/L had only a moderate sensitivity (0.46) and specificity (0.82) for predicting severe parenchymal bleeding (parenchymal hemorrhage 2).

Conclusions—

Elevated S100B serum levels before thrombolytic therapy constitute an independent risk factor for HT in patients with acute stroke. Unfortunately, the diagnostic accuracy of S100B is too low for it to function in this context as a reliable biomarker in clinical practice.
Computation of Hemodynamics in the Circle of Willis
Authors: Alnæs Martin Sandve , Isaksen Jørgen , Mardal Kent-André , Romner Bertil , Morgan Michael K. , Ingebrigtsen Tor
Published: August 2007

Background and Purpose—

Wall shear stress (WSS) and pressure are important factors in the development of cerebral aneurysms. We aimed to develop a computational fluid dynamics simulator for flow in the complete circle of Willis to study the impact of variations in vessel radii and bifurcation angles on WSS and pressure on vessel walls.

Methods—

Blood flow was modeled with Navier-Stokes equations as an incompressible newtonian fluid within rigid vessel walls. A model of the circle of Willis geometry was approximated as a network of tubes around cubic curves. Pulsatile inlet flow rates and constant outlet pressure were used as boundary conditions.

Results—

The simulations confirmed that differences in vessel radii and asymmetric branch angles influence WSS magnitude and spatial distribution. High WSS occurred at locations where aneurysms are frequent and in anatomic variants known to be associated with an increased risk for aneurysm development.

Conclusions—

Computational fluid dynamics analysis can be applied to the complete circle of Willis and should be used to study the pathophysiology of this complex vascular structure, including risk factors for aneurysm development. Further development of the method should include simulations with flexible vessel walls.
Occupational Therapists’ Identification, Assessment, and Treatment of Unilateral Spatial Neglect During Stroke Rehabilitation in Canada
Authors: Menon-Nair Anita , Korner-Bitensky Nicol , Ogourtsova Tatiana
Published: August 2007

Background and Purpose—

Unilateral spatial neglect (USN) is a disabling feature of stroke, and its identification and management are critical for optimizing patient outcomes. This study examined USN problem identification, assessment, and treatment among clinicians working in stroke rehabilitation.

Methods—

This report was based on a Canada-wide survey of 253 occupational therapists providing inpatient stroke rehabilitation.

Results—

Eighty percent (n=202) recognized USN as a potential problem, 27% (n=67) reported using standardized USN assessment tools, and 58% (n=147) indicated using USN interventions. Working on a stroke unit and younger age were among the variables explaining 7% to 19% of the variability in USN problem identification, assessment, and intervention use.

Conclusions—

Although USN problem identification was high, clinicians were unlikely to use standardized assessment tools or evidence-based interventions to effectively manage this serious impairment.
Racial/Ethnic Differences in Longitudinal Risk of Intracranial Hemorrhage in Brain Arteriovenous Malformation Patients
Authors: Kim Helen , Sidney Stephen , McCulloch Charles E. , Poon K. Y. Trudy , Singh Vineeta , Johnston S. Claiborne , Ko Nerissa U. , Achrol Achal S. , Lawton Michael T. , Higashida Randall T. , Young William L.
Published: August 2007

Background and Purpose—

Race/ethnicity is associated with overall incidence of intracranial hemorrhage (ICH), but its impact in patients with brain arteriovenous malformation is unknown. We evaluated whether race/ethnicity was a risk factor for ICH in the natural course in a large, multiethnic cohort of patients with brain arteriovenous malformation followed longitudinally.

Methods—

Data were collected prospectively for patients with brain arteriovenous malformation evaluated at the University of California, San Francisco (n=436) and retrospectively through databases and chart review in the 20 hospitals of the Kaiser Permanente Medical Care Program (n=1028). Multivariate Cox regression was performed to assess the influence of race/ethnicity on subsequent ICH, adjusting for risk factors. Cases were censored at first treatment, loss to follow-up, or death.

Results—

Average follow up was 4.7±8.0 years for Kaiser Permanente Medical Care Program patients and 2.8±7.3 years for University of California, San Francisco patients with no difference in time to ICH between cohorts (log rank
P
=0.57). The annualized 5-year ICH rate was 2.1% (3.7% for ruptured at presentation; 1.4% for unruptured). Initial ICH presentation (hazard ratio: 3.0, 95% CI: 1.9 to 4.9,
P
<0.001) and Hispanic race/ethnicity (hazard ratio: 1.9, 95% CI: 1.1 to 3.3,
P
=0.02) were independent predictors of ICH, adjusting for age, gender, cohort, and a cohort–age interaction. The ICH risk for Hispanics versus whites increased to 3.1 (95% CI: 1.3 to 7.4,
P
=0.013) after further adjusting for arteriovenous malformation size and deep venous drainage in a subset of cases with complete data. Similar trends were observed for blacks (hazard ratio: 2.1, 95% CI: 0.9 to 4.8,
P
=0.09) and Asians (hazard ratio: 2.4, 95% CI: 0.8 to 7.1,
P
=0.11), although nonsignificant.

Conclusions—

This study reports the first description of race/ethnic differences in brain arteriovenous malformation, with Hispanics at an increased risk of subsequent ICH compared with whites.
South Atlantic Variability Arising from Air–Sea Coupling: Local Mechanisms and Tropical–Subtropical Interactions
Authors: Trzaska Sylwia , Robertson Andrew W. , Farrara John D. , Mechoso Carlos R.
Published: August 2007

Interannual variability in the southern and equatorial Atlantic is investigated using an atmospheric general circulation model (AGCM) coupled to a slab ocean model (SOM) in the Atlantic in order to isolate features of air–sea interactions particular to this basin. Simulated covariability between sea surface temperatures (SSTs) and atmosphere is very similar to the observed non-ENSO-related covariations in both spatial structures and time scales. The leading simulated empirical coupled mode resembles the zonal mode in the tropical Atlantic, despite the lack of ocean dynamics, and is associated with baroclinic atmospheric anomalies in the Tropics and a Rossby wave train extending to the extratropics, suggesting an atmospheric response to tropical SST forcing. The second non-ENSO mode is the subtropical dipole in the SST with a mainly equivalent barotropic atmospheric anomaly centered on the subtropical high and associated with a midlatitude wave train, consistent with atmospheric forcing of the subtropical SST.

The power spectrum of the tropical mode in both simulation and observation is red with two major interannual peaks near 5 and 2 yr. The quasi-biennial component exhibits a progression between the subtropics and the Tropics. It is phase locked to the seasonal cycle and owes its existence to the imbalances between SST–evaporation and SST–shortwave radiation feedbacks. These feedbacks are found to be reversed between the western and eastern South Atlantic, associated with the dominant role of deep convection in the west and that of shallow clouds in the east. A correct representation of tropical–extratropical interactions and of deep and shallow clouds may thus be crucial to the simulation of realistic interannual variability in the southern and tropical Atlantic.
Comments on “Testing the Fidelity of Methods Used in Proxy-Based Reconstructions of Past Climate”
Authors: Zorita Eduardo , Gonzalez-Rouco Fidel , von Storch Hans
Published: August 2007

Mann et el. found that a version of the Regularized Expectation Maximization (RegEM) method to reconstruct the temperatures of the last millennium showed similar results to previous reconstructions in one of their earlier papers. They also tested the RegEM method in the surrogate climate of a simulation with the Climate System Model (CSM) and found no attenuation of the pseudoreconstructed centennial variability of the Northern Hemisphere mean temperature compared to the one simulated by the model. This is in contrast with the results by von Storch et al., who found, in a simulation with ECHO-G model, that the earlier Mann et al. method underestimates the centennial temperature variability of the Northern Hemisphere temperature. The newer paper by Mann et al. explains that this difference is in part due to the unrealistic character of the ECHO-G simulation. However, it is shown here that similar results to those of von Storch et al. are also found in an ECHO-G simulation that closely resembles the CSM simulation used by Mann et al. Therefore, it is argued here that this discrepancy could be related to other factors, probably to the use of a longer calibration period and to the difference between RegEM and the original method by Mann et al.
Cluster Analysis of Typhoon Tracks. Part I: General Properties
Authors: Camargo Suzana J. , Robertson Andrew W. , Gaffney Scott J. , Smyth Padhraic , Ghil Michael
Published: August 2007

A new probabilistic clustering technique, based on a regression mixture model, is used to describe tropical cyclone trajectories in the western North Pacific. Each component of the mixture model consists of a quadratic regression curve of cyclone position against time. The best-track 1950–2002 dataset is described by seven distinct clusters. These clusters are then analyzed in terms of genesis location, trajectory, landfall, intensity, and seasonality.

Both genesis location and trajectory play important roles in defining the clusters. Several distinct types of straight-moving, as well as recurving, trajectories are identified, thus enriching this main distinction found in previous studies. Intensity and seasonality of cyclones, though not used by the clustering algorithm, are both highly stratified from cluster to cluster. Three straight-moving trajectory types have very small within-cluster spread, while the recurving types are more diffuse. Tropical cyclone landfalls over East and Southeast Asia are found to be strongly cluster dependent, both in terms of frequency and region of impact.

The relationships of each cluster type with the large-scale circulation, sea surface temperatures, and the phase of the El Niño–Southern Oscillation are studied in a companion paper.
Physical Processes Associated with the Tropical Atlantic SST Gradient during the Anomalous Evolution in the Southeastern Ocean
Authors: Hu Zeng-Zhen , Huang Bohua
Published: August 2007

This work is focused on the evolution of the dominant air–sea coupled mode in the equatorial and southeastern tropical Atlantic and the associated physical processes. It is shown that in June–August (JJA) the evolution of the dominant mode is mainly dynamically driven and displays a coherent warming or cooling pattern extending from the Angola coast toward the equator in the Gulf of Guinea. For anomalies peaking in JJA, the warming (cooling) is initiated near the Angola coast in March–May. It is suggested that SST anomalies along the coast and near the equator are physically connected. The air–sea interaction along the coast may be a major factor in triggering the development of SST anomalies near the equator, which is intensified by local positive feedbacks that may include Bjerknes and Ekman processes. In return, the warming or cooling near the equator weaken the SST anomalies along the coast by changing the direction of anomalous wind. Slow westward Rossby wave propagation may also play a role in stimulating the equatorial feedback. The thermodynamic processes affect the evolution of this mode. On average, the net surface latent heat flux anomalies are the leading damping factor, and the net surface sensible heat flux plays the same role on a smaller scale, while the net surface shortwave (longwave) radiation heating has a negative (positive) contribution to the SST variation. However, although on average the surface heat flux damps the SST anomalies, the role played by the heat flux varies with regions and components. Spatially, the latent and sensible heat flux as well as the longwave radiation damp air–sea coupling in the eastern South Atlantic near the Gulf of Guinea and amplify the coupling in the western equatorial ocean. The situation is opposite for the solar radiation.
Coupled Decadal Variability in the North Pacific: An Observationally Constrained Idealized Model*
Authors: Qiu Bo , Schneider Niklas , Chen Shuiming
Published: August 2007

Air–sea coupled variability is investigated in this study by focusing on the observed sea surface temperature signals in the Kuroshio Extension (KE) region of 32°–38°N and 142°E–180°. In this region, both the oceanic circulation variability and the heat exchange variability across the air–sea interface are the largest in the midlatitude North Pacific. SST variability in the KE region has a dominant time scale of ∼10 yr and this decadal variation is caused largely by the regional, wind-induced sea surface height changes that represent the lateral migration and strengthening/weakening of the KE jet. The importance of the air–sea coupling in influencing KE jet is explored by dividing the large-scale wind forcing into those associated with the intrinsic atmospheric variability and those induced by the SST changes in the KE region. The latter signals are extracted from the NCEP–NCAR reanalysis data using the lagged correlation analysis. In the absence of the SST feedback, the intrinsic atmospheric forcing enhances the decadal and longer time-scale SST variance through oceanic advection but fails to capture the observed decadal spectral peak. When the SST feedback is present, a warm (cold) KE SST anomaly works to generate a positive (negative) wind stress curl in the eastern North Pacific basin, resulting in negative (positive) local sea surface height (SSH) anomalies through Ekman divergence (convergence). As these wind-forced SSH anomalies propagate into the KE region in the west, they shift the KE jet and alter the sign of the preexisting SST anomalies. Given the spatial pattern of the SST-induced wind stress curl forcing, the optimal coupling in the midlatitude North Pacific occurs at the period of ∼10 yr, slightly longer than the basin-crossing time of the baroclinic Rossby waves along the KE latitude.
Decadal Changes of Wind Stress over the Southern Ocean Associated with Antarctic Ozone Depletion
Authors: Yang Xiao-Yi , Huang Rui Xin , Wang Dong Xiao
Published: August 2007

Using 40-yr ECMWF Re-Analysis (ERA-40) data and in situ observations, the positive trend of Southern Ocean surface wind stress during two recent decades is detected, and its close linkage with spring Antarctic ozone depletion is established. The spring Antarctic ozone depletion affects the Southern Hemisphere lower-stratospheric circulation in late spring/early summer. The positive feedback involves the strengthening and cooling of the polar vortex, the enhancement of meridional temperature gradients and the meridional and vertical potential vorticity gradients, the acceleration of the circumpolar westerlies, and the reduction of the upward wave flux. This feedback loop, together with the ozone-related photochemical interaction, leads to the upward tendency of lower-stratospheric zonal wind in austral summer. In addition, the stratosphere–troposphere coupling, facilitated by ozone-related dynamics and the Southern Annular Mode, cooperates to relay the zonal wind anomalies to the upper troposphere. The wave–mean flow interaction and the meridional circulation work together in the form of the Southern Annular Mode, which transfers anomalous wind signals downward to the surface, triggering a striking strengthening of surface wind stress over the Southern Ocean.
On Sub-ENSO Variability
Authors: Keenlyside Noel S. , Latif Mojib , Dürkop Anke
Published: August 2007

Multichannel singular spectrum analysis (MSSA) of surface zonal wind, sea surface temperature (SST), 20° isotherm depth, and surface zonal current observations (between 1990 and 2004) identifies three coupled ocean–atmosphere modes of variability in the tropical Pacific: the El Niño–Southern Oscillation (ENSO), the annual cycle, and a mode with a 14–18-month period, which is referred to as sub-ENSO in this study. The sub-ENSO mode accounts for the near 18-month (near annual) variability prior to (following) the 1997/98 El Niño event. It was strongest during this El Niño event, with SST anomalies exceeding 1°C. Sub-ENSO peak SST anomalies are ENSO-like in structure and are associated with eastward propagating heat content variations. However, the SST anomalies are preceded by and in near quadrature with relatively strong remotely forced westward propagating zonal current variations, suggesting the sub-ENSO mode arises from the zonal-advective feedback.

The sub-ENSO mode is found to exist also in an intermediate complexity model (ICM) of the tropical Pacific. A heat budget analysis of the model’s sub-ENSO mode shows it indeed arises from the zonal-advective feedback. In the model, both ENSO and sub-ENSO modes coexist, but there is a weak nonlinear interaction between them. Experiments also show that the observed changes in sub-ENSO’s characteristics may be explained by changes in the relative importance of zonal and vertical advection SST tendencies.
A Synoptic Climatology of the Central United States and Associations with Pacific Teleconnection Pattern Frequency
Authors: Coleman Jill S. M. , Rogers Jeffrey C.
Published: August 2007

A synoptic climatological weather classification scheme incorporating both surface and upper-air data is developed for the central United States based on an automated two-step cluster analysis. It employs daily NCEP–NCAR reanalysis data over all seasons of 57 yr (1948–2004) in creating synoptic types from surface and upper-air (925, 850, 700, and 500 hPa) temperature and humidity data as well as sea level pressure, geopotential heights, and winds aloft. The cluster analysis creates 10 synoptic types exhibiting distinct seasonal preferences, with three each that occur primarily in summer and winter, and four that occur primarily in winter and the transition seasons, particularly spring. The typing scheme generates synoptic patterns largely characterized by distinctive surface circulations, baroclinic vertical structure, and thermal advection. Interannual variations occur in the frequencies of the synoptic types, some of which are out of phase with each other. The annual frequencies of two winter synoptic types, associated respectively with strong zonal and meridional flow, are highly correlated (r ≫ 0.63–0.73) to the phase of the Pacific–North American teleconnection pattern, while Niño-3.4 equatorial Pacific sea surface temperatures are linked to a synoptic type producing low pressure around the Gulf Coast.
Investigating the Impact of Reemerging Sea Surface Temperature Anomalies on the Winter Atmospheric Circulation over the North Atlantic
Authors: Cassou Christophe , Deser Clara , Alexander Michael A.
Published: August 2007

Extratropical SSTs can be influenced by the “reemergence mechanism,” whereby thermal anomalies in the deep winter mixed layer persist at depth through summer and are then reentrained into the mixed layer in the following winter. The impact of reemergence in the North Atlantic Ocean (NAO) upon the climate system is investigated using an atmospheric general circulation model coupled to a mixed layer ocean/thermodynamic sea ice model.

The dominant pattern of thermal anomalies below the mixed layer in summer in a 150-yr control integration is associated with the North Atlantic SST tripole forced by the NAO in the previous winter as indicated by singular value decomposition (SVD). To isolate the reemerging signal, two additional 60-member ensemble experiments were conducted in which temperature anomalies below 40 m obtained from the SVD analysis are added to or subtracted from the control integration. The reemerging signal, given by the mean difference between the two 60-member ensembles, causes the SST anomaly tripole to recur, beginning in fall, amplifying through January, and persisting through the following spring. The atmospheric response to these SST anomalies resembles the circulation that created them the previous winter but with reduced amplitude (10–20 m at 500 mb per °C), modestly enhancing the winter-to-winter persistence of the NAO. Changes in the transient eddies and their interactions with the mean flow contribute to the large-scale equivalent barotropic response throughout the troposphere. The latter can also be attributed to the change in occurrence of intrinsic weather regimes.
Group Problem Solving and Anxiety During a Simulated Mountaineering Ascent
Authors: Tougne Jerome , Paty Benjamin , Meynard Dorothée , Martin Jean-Michel , Letellier Thierry , Rosnet Elisabeth
Published: August 2007

Eight mountaineers were placed in a hypobaric chamber to simulate oxygen depletion accompanying a mountain ascent. The aim was to examine the evolution of individual and group efficiency in problem solving and anxiety according to simulated altitude. Relationships within the group, state and trait anxiety, and individual and collective performance in problem solving were repeatedly assessed at simulated altitudes of 5000m, 6000m, 7000m, and 8000m. The decrease of individual performance in problem solving, shown to be simultaneous to the increase of state anxiety, had little effect on collective performance in problem solving. These results suggest (a) that the collective success could be due to the emergence of a positive common goal and a positive appraisal of the situation and (b) that the state anxiety could act as a mediator between the variation in altitude and its effects on individual performance. The relevance of these results to real mountaineering expeditions is discussed.
Tenure Choice in the Housing Market
Authors: Ben-Shahar Danny
Published: August 2007

The author conducted a survey to examine psychological and economic factors affecting the homeownership–tenancy choice. Among the many results, the author found disturbing evidence according to which there exists a fundamental flawed reasoning in the common judgment of the financial superiority of ownership over tenancy. Most important, however, the author finds that although psychological and economic factors involved in the tenure decision are highly correlated, the psychological factors are found to be more statistically significant in explaining the realized tenure mode. This, in turn, may suggest that psychological effects might act as the underlying forces for determining the apparent economic tenure decision.
A Collective Interest Model Approach to Explain the Benefit–Cost Expectations of Participating in a Collaborative Institution
Authors: Weible Christopher M.
Published: August 2007

What factors explain stakeholder benefit–cost expectations for participating in a collaborative institution? This article examines this question by applying a version of the collective interest model. The case study includes original data from a mail-in questionnaire and in-person interviews of stakeholders' expectations before the start of a collaborative process to establish marine-protected areas in California. The results provide little support for the traditional variables in the collective interest model with null results for group and personal efficacy. Selective incentives, especially putting in your own time versus company time, are important in explaining stakeholders' benefit–cost expectations. The results show that ally efficacy is an important factor, suggesting that perceptions of allies compared to opponents shape initial expectations for a collaborative process. This article adds to the research on political participation in environmental management by presenting a rare exploration of ex ante beliefs before the start of a collaborative planning institution.
Value Orientations to Explain Beliefs Related to Environmental Significant Behavior
Authors: de Groot Judith I. M. , Steg Linda
Published: August 2007

In environmental literature it is argued that three different value orientations may be relevant for understanding environmental beliefs and intentions: egoistic, altruistic, and biospheric. Until now, the distinction between altruistic and biospheric value orientations has hardly been supported empirically. In this article, three studies are reported aimed to examine whether an egoistic, altruistic, and biospheric value orientation can indeed be distinguished empirically by using an adapted value instrument. Also, it is examined whether these value orientations are differently and uniquely related to general and specific beliefs and behavioral intention. Results provide support for the reliability and validity of the value instrument. All studies replicated the distinction into three value orientations, with sufficient internal consistency. Furthermore, when altruistic and biospheric goals conflict, they seem to provide a distinct basis for proenvironmental intentions. The value instrument could therefore be useful to better understand relationships between values, beliefs, and intentions related to environmentally significant behavior.
Using Brand Personality to Differentiate Regional Tourism Destinations
Authors: Murphy Laurie , Moscardo Gianna , Benckendorff Pierre
Published: August 2007

Destination branding is growing rapidly as an approach to tourism destination promotion. While this concept has been borrowed from the world of general consumer goods and applied in a number of national tourism destinations, academic analysis of the value and effectiveness of destination branding has emerged more slowly. The present article addresses this paucity of academic scrutiny by examining the value of the destination brand personality construct in distinguishing between two regional tourism destinations. A survey of 480 tourists was conducted adjacent to the Great Barrier Reef in Northern Australia to gather data about the destination image attributes of two regional destinations that were branded by a state destination marketing organization. The results indicated that tourists were able to articulate different destination brand personalities for each region. The results also indicated that more work might need to be done to adapt existing frameworks of brand personality to the tourism context.
Promoting Tourism Destination Image
Authors: Govers Robert , Go Frank M. , Kumar Kuldeep
Published: August 2007

This article examines the role of tourism promotion as a component of destination image formation. It reports the findings of a study in which 1,100 respondents from around the globe described their previsit perceived image of seven sample destinations, as well as the information sources they used. The findings suggest that tourism promotion does not have a major impact upon the perceptions of travelers and that other sources of information have a much greater bearing on the formation of destination image. As a result, tourism authorities need to understand that successful tourism promotion is dependent on a broad range of external influences. At the same time, the impact of marketing communication decisions on measurables such as revenue, market share, and costs must be carefully assessed.
The Effectiveness of Print Advertising Stimuli in Evoking Elaborate Consumption Visions for Potential Travelers
Authors: Walters Gabrielle , Sparks Beverley , Herington Carmel
Published: August 2007

Two imagery-evoking strategies are examined to determine their effectiveness in producing an elaborate consumption vision. Specifically, a 3 × 3 factorial experimental design is employed to examine the effects of pictures and text as advertising stimuli to evoke elaborate consumption visions among the participants within the context of holiday decision making. A MANOVA revealed a main effect for each of the two stimuli. The presence of more concrete pictures contributed to the extent of elaboration and the quality of consumers' consumption visions. Furthermore, the addition of concrete words together with instructions to imagine increased the elaboration and quality of the consumption vision. A significant interaction effect between the picture and text variables demonstrated that combining instructions to imagine with concrete pictures is the most efficacious strategy. The article discusses the implications of the findings for theory as well as offering an application of the results for tourism destination marketers.
Travel Blogs and the Implications for Destination Marketing
Authors: Pan Bing , MacLaurin Tanya , Crotts John C.
Published: August 2007

This study explores travel blogs as a manifestation of travel experience. Visitor opinions posted on leading travel blog sites were analyzed to gain an understanding of the destination experience being manifested. Travel blogs on Charleston, South Carolina, were collected through the three most popular travel blog sites and three blog search engines. Blogs were analyzed using semantic network analysis and content analysis methods to ascertain what bloggers were communicating about their travel experiences. Results revealed that major strengths of the destination were its attractions: historic charm, Southern hospitality, beaches, and water activities. Major weaknesses included weather, infrastructure, and fast-service restaurants. Qualitative results demonstrated that travel blogs are an inexpensive means to gather rich, authentic, and unsolicited customer feedback. Information technology advances and increasingly large numbers of travel blogs facilitate travel blog monitoring as a cost-effective method for destination marketers to assess their service quality and improve travelers' overall experiences.
Tourism Destination Competitiveness: From Definition to Explanation?
Authors: Mazanec Josef A. , Wöber Karl , Zins Andreas H.
Published: August 2007

This article contributes to the recent literature on tourism destination competitiveness including the gargantuan compilations of competitiveness factors by Ritchie and Crouch (2003), or Dwyer and Kim (2003), and, particularly, the widely known prototype of a Competitiveness Monitor (CM) initiated by the World Travel and Tourism Council (WTTC). The central question underlying this article is whether an arrangement of data such as the CM can be transformed from a purely definitional system into an explanatory model. A number of criticisms regarding the way of constructing the CM, its epistemological nature, and the absence of any accessibility factors lead to a moderately revised system that is explored by latent variable modeling. The empirical findings support this type of model, which tends to better explain the levels of tourism activity already achieved than sustained tourism growth. A discussion of the detailed results produces several recommendations on how to adjust the future strategy of research on destination competitiveness.
New Paradigms in City Tourism Management: Redefining Destination Promotion
Authors: Paskaleva-Shapira Krassimira A.
Published: August 2007

This article outlines basic concepts, issues, and key challenges to competitive and sustainable urban tourist destinations. Given the complex nature of cities, it is argued that the promotion of urban tourist destinations requires a citywide integrated management approach based on governance principles and strategic vision of competitiveness. The discussion in the article centers on global challenges, a review of the literature, and an assessment of emerging trends, needs, and opportunities for city destinations. There is a focus on key constructs promoted by the First World Forum of Urban Tourism in 2005: competitiveness, sustainability, value, and quality. New paradigms of successful destination management are defined with regard to a conceptual approach to competitiveness, cultural heritage tourism, city branding, visitor perception, and urban quality of life. A conclusion is made that promotion of tourist cities should be redefined to creating a city appeal that is aspiring to all stakeholders—tourists, businesses, and citizens.
Analysis of Logic
Authors: Keeler Rebecca L.
Published: August 2007

Public policies are replete with category structures meant to sort and count target populations. This article analyzes categories for HIV risk exposure of U.S. federal policy beneficiaries. Close examination of the category scheme reveals that the categories are not perfectly logical or consistent. Furthermore, changing demographics of the affected population suggests focus should be on differently defined categories. Continued usage of the existing categories may be hindering more effective policy response to the changing demographics of HIV. This article applies Yanow's race and ethnic category analysis in a new context, further illustrating the implications of category definitions in public policies.
Integrating Two Subtypes of Depression
Authors: Abela John R. Z. , Sakellaropoulo Maya , Taxel Elizabeth
Published: August 2007

According to Blatt and Zuroff's 1992 specific vulnerability hypothesis, individuals high in self-criticism or dependency will likely exhibit increases in depressive symptoms following negative achievement and interpersonal events, respectively. The hopelessness theory hypothesizes a distinct subtype of depression, hopelessness depression, with a unique symptom profile. Recent evidence suggests a possible link between dependency or self-criticism and hopelessness depression. The present study examined whether early adolescents with high levels of self-criticism and/or dependency are vulnerable to developing hopelessness depression symptoms following negative events congruent with their personality predispositions. Seventy-nine seventh grade children completed questionnaires assessing self-criticism, dependency, and depressive symptoms. Ten weeks later, depressive symptoms and the occurrence of negative events were assessed. In line with hypotheses, children high in self-criticism exhibited increases in hopelessness but not nonhopelessness depression symptoms following negative achievement but not interpersonal events. Contrary to predictions, children high in dependency exhibited no increases in hopelessness or nonhopelessness depression symptoms following negative events in either domain.
Self-Esteem
Authors: Michaels Marcia L. , Barr Alicia , Roosa Mark W. , Knight George P.
Published: August 2007

Global self-worth and five domains of self-esteem (scholastic competence, athletic competence, physical appearance, behavioral conduct, social acceptance) were tested for measurement equivalence in a sample of Anglo American, Mexican American, African American, and Native American youth aged 9 through 14 years. The results revealed that global self-worth and scholastic competence showed strong factorial invariance in all groups, and the remaining self-esteem domains showed strong factorial invariance in some of the groups. Functional equivalence analyses revealed that the relations between self-esteem and two developmental outcome variables, conduct disorder and attitudes toward substance use, were similar in groups in which strong factorial invariance was established. Implications for multiethnic studies and self-esteem research are discussed.
The Effect of Testing Condition on Word Guessing in Elementary School Children
Authors: Männamaa Mairi , Kikas Eve , Raidvee Aire
Published: August 2007

Elementary school children's word guessing is studied, and the results from individual and collective testing conditions are compared. The participants are 764 students from the second, third, and fourth grades (ages 8-11, 541 students from mainstream regular classes and 223 students with learning disabilities). About half of these students are collectively tested in the classroom, and half of the students are individually tested in a separate room. The psychometric properties of the test are good for both individual and collective testing conditions. Students generally score higher in the collective condition compared to the individual condition in both groups. In the control group, this tendency is apparent in all three grades, whereas in the group of students with learning disabilities, it is demonstrated only in the third grade.