bluuebunny/crossref_metadata_2025 huggingface dataset:
Toll-Like Receptor 9 Signaling Is Critical for Early Experimental Deep Vein Thrombosis Resolution
Authors: Henke Peter K. , Mitsuya Mayo , Luke Catherine E. , Elfline Megan A. , Baldwin Joseph F. , Deatrick K. Barry , Diaz Jose A. , Sood Vikram , Upchurch Gilbert R. , Wakefield Thomas W. , Hogaboam Cory , Kunkel Steven L.
Published: October 2010

Objective—

Toll-like receptors (TLR) bridge innate immunity and host responses, including inflammation. Sterile inflammation such as a venous thrombus (V
t
) may involve TLR signaling, including TLR9.

Methods and Results—

TLR9 signaling on thrombus resolution was investigated using a mouse model of stasis V
t
. V
t
were significantly larger in TLR9−/− mice compared with wild-type (WT) at 2 and 8 days, despite a 2-fold increase in thrombus polymorphonucleic neutrophils at 2 days and monocytes at 8 days, whereas thrombus collagen and neovascularization was 55% and 37% less, respectively, at 8 days. Coincidently, decreased fibrinogen and increased thrombin-antithrombin complex were observed in TLR9−/− mouse thrombi. Vein wall interferon-α, interleukin-1α, and interleukin-2 were significantly reduced in TLR9−/− mice compared with WT. Thrombus cell death pathway markers were not significantly altered at 2 days, but caspase-1 was reduced in TLR9−/− thrombi at 8 days. MyD88 confers TLR9 intracellular signaling, but MyD88−/− mice had V
t
resolution similar to that of WT. However, inhibition of the NOTCH ligand δ-like 4 was associated with larger V
t
. Finally, stimulation with a TLR9 agonist was associated with smaller V
t
.

Conclusion—

TLR9 signaling is integral for early and mid-V
t
resolution through modulation of sterile inflammation, maintaining a TH1 milieu, and effects on the thrombosis pathway.
Identifying Patients at High Risk for Stroke Despite Anticoagulation
Authors: Lip Gregory Y.H. , Frison Lars , Halperin Jonathan L. , Lane Deirdre A.
Published: October 2010

Background and Purpose—

The risk of stroke in patients with atrial fibrillation (AF) is not homogeneous, and various clinical risk factors have informed the development of stroke risk stratification schemes (RSS). Among anticoagulated cohorts, the emphasis should be on the identification of patients who remain at high risk for stroke despite anticoagulation.

Methods—

We investigated predictors of thromboembolism (TE) risk in an anticoagulated AF clinical trial cohort (n=7329 subjects) and tested the predictive value of contemporary RSS in this cohort: CHADS
2
, Framingham, NICE 2006, American College of Cardiology/American Heart Association/European Society of Cardiology 2006, the 8th American College of Chest Physicians guidelines and the CHA
2
DS
2
-VASc schemes.

Results—

On multivariate analysis, significant predictors of TE were stroke/TIA (hazard ratio [HR], 2.24;
P
<0.001), age 75 years or older (HR, 1.77;
P
=0.0002), coronary artery disease (HR, 1.52;
P
=0.0047), and smoking (HR, 2.10;
P
=0.0005), whereas reported alcohol use (HR, 0.70;
P
=0.02) was protective. Comparison of contemporary RSS demonstrated variable classification of AF patients into risk strata, although
c
-statistics for TE were broadly similar among the RSS tested and varied between 0.575 (NICE 2006) and 0.647 (CHA
2
DS
2
-VASc). CHA
2
DS
2
-VASc classified 94.2% as being at high risk, whereas most other RSS categorized two-thirds as being at high risk. Of the 184 TE events, 181 (98.4%) occurred in patients identified as being at high risk by the CHA
2
DS
2
-VASc schema. There was a stepwise increase in TE with increasing CHA
2
DS
2
-VASc score (
P
trend
<0.0001), which had the highest HR (3.75) among the tested schemes. The negative predictive value (ie, the percent categorized as “not high risk” actually being free from TE) for CHA
2
DS
2
-VASc was 99.5%.

Conclusion—

Coronary artery disease and smoking are additional risk factors for TE in anticoagulated AF patients, whereas alcohol use appears protective. Of the contemporary stroke RSS, the CHA
2
DS
2
-VASc scheme correctly identified the greatest proportion of AF patients at high risk, despite the similar predictive ability of most RSS evidenced by the
c
-statistic.
Functional Occurrence of the Interaction of Tissue Plasminogen Activator With the NR1 Subunit of
N
-Methyl-
d
-Aspartate Receptors During Stroke
Authors: Macrez Richard , Bezin Laurent , Le Mauff Brigitte , Ali Carine , Vivien Denis
Published: October 2010

Background and Purpose—

Despite its fibrinolytic effect, tissue-type plasminogen activator (tPA) displays deleterious effects in the brain, including proexcitotoxicity, that can reduce the overall benefit from thrombolysis during stroke. We have proposed that tPA potentiates excitotoxicity by interacting with and cleaving the aminoterminal end of the NR1 subunit of
N
-methyl-
d
-aspartate receptors, leading to an increased calcium influx, Erk1/2 activation, and neurotoxicity. Because this mechanism is debated, our aim was to demonstrate its in vivo occurrence and relevance. Because tPA is released under ischemic conditions, we hypothesized that if it indeed processes NR1, then the released fragment should reactivate the immune system in animals that had been immunized long before with recombinant aminoterminal end of the NR1. This effect should be exacerbated in ischemic animals thrombolysed with recombinant tPA.

Methods—

At a time when specific antibodies could not be detected any longer, mice previously vaccinated with recombinant aminoterminal end of the NR1 were subjected to thromboembolic stroke induced by injecting thrombin in the middle cerebral artery alone or with intravenous thrombolysis.

Results—

Stroke performed 1 year after active immunization induced the reappearance of antibodies against the aminoterminal end of the NR1 in the plasma, an effect significantly increased when ischemia was followed by recombinant tPA-induced reperfusion. Moreover, immunization preventing the interaction of tPA with aminoterminal end of the NR1 reduced ischemic brain damages and extended the therapeutic window of tPA-induced thrombolysis.

Conclusion—

We demonstrate that the tPA-dependent interaction and cleavage of the NR1 subunit of
N
-methyl-
d
-aspartate receptors occurs in vivo after stroke and that this interaction is a relevant therapeutic target for stroke treatment.
Age- and Gender-Specific Prevalence of Cardiovascular Risk Factors in 40 102 Patients With First-Ever Ischemic Stroke
Authors: Andersen Klaus Kaae , Andersen Zorana Jovanovic , Olsen Tom Skyhøj
Published: October 2010

Background and Purpose—

We describe the prevalence of cardiovascular risk factors at stroke onset in men and women of all ages.

Methods—

A registry started in 2001, designed to register all hospitalized stroke patients in Denmark, now holds 40 102 patients with first-ever ischemic stroke. Patients underwent evaluation including stroke severity (Scandinavian Stroke Scale), CT, and cardiovascular risk factors: hypertension, atrial fibrillation, diabetes mellitus, intermittent arterial claudication, previous myocardial infarction, body mass index, smoking, and alcohol consumption. We estimated the independent effect of gender and age on prevalence of cardiovascular risk factors and calculated age and gender-specific prevalence rates for each risk factor.

Results—

The register contained 47.9% women and 52.1% men. Men had more often diabetes mellitus, previous myocardial infarction, intermittent arterial claudication, and over the limit alcohol consumption. Women had more often hypertension and obesity. Atrial fibrillation and smoking were equally frequent in both genders. Age stratification revealed that the lifestyle cardiovascular risk factors smoking, alcohol, and obesity were more common in the younger patients with stroke (<60 years), whereas prevalence of hypertension, diabetes mellitus, myocardial infarction, intermittent arterial claudication, and, in men, also atrial fibrillation decreases in the elderly (>70 to 80 years), the decrease being generally more pronounced in men than in women.

Conclusion—

Cardiovascular risk factors were generally more prevalent in men. Lifestyle cardiovascular risk factors were more common in the young. Prevalence of hypertension, diabetes mellitus, coronary heart disease, and, in men, also atrial fibrillation go down after the age of 70 to 80 years.
Genomewide Linkage and Peakwide Association Analyses of Carotid Plaque in Caribbean Hispanics
Authors: Dong Chuanhui , Beecham Ashley , Slifer Susan , Wang Liyong , Blanton Susan H. , Wright Clinton B. , Rundek Tatjana , Sacco Ralph L.
Published: October 2010

Background and Purpose—

Atherosclerosis is a complex subclinical cardiovascular disorder with a substantial genetic component. This study sought to identify genetic loci influencing carotid plaque in 2 independent samples.

Methods—

B-mode ultrasound was performed to determine the presence and area of carotid plaque. Variance components analysis was used to test for linkage using 383 autosomal microsatellite markers in 1308 subjects from 100 Dominican families. Multiple linear and logistic regression models were used to investigate the association between plaque traits and 18 904 single nucleotide polymorphisms under the 1-logarithm of odds unit down regions of linkage peaks in an independent community-based data set (N=941, 41% Dominicans) from the Northern Manhattan Study.

Results—

After adjustment for age, hypertension, diabetes mellitus, cigarette pack-years, body mass index, and waist-to-hip ratio, significant heritability was detected for plaque presence (h
2
=0.50±0.14,
P
<0.0001) and plaque area (h
2
=0.17±0.04,
P
<0.0001). Quantitative and dichotomous trait linkage analyses obtained similar results and identified 4 regions with multipoint logarithm of odds scores ≥2.00 on 7q36, 11p15, 14q32, and 15q23. In the association analysis of the 4 linkage peaks, several single nucleotide polymorphisms in or near
SOX6, FSD2, AP3S2, EFTUD1
, and
MYOD1
were associated with carotid plaque traits with a nominal
P
≤0.0005 in the Northern Manhattan Study data set and with a
P
≤0.01 in Northern Manhattan Study Dominican subset.

Conclusions—

Carotid plaque has considerable heritability and may be influenced by loci on chromosomes 11p15, 14q32, and 15q23. The
SOX6
gene within the bone morphogenic protein pathway could be a candidate for carotid plaque. Larger independent studies are needed to validate these findings.
Hepatitis C Virus Infection and Increased Risk of Cerebrovascular Disease
Authors: Lee Mei-Hsuan , Yang Hwai-I , Wang Chih-Hao , Jen Chin-Lan , Yeh Shiou-Hwei , Liu Chun-Jen , You San-Lin , Chen Wei J. , Chen Chien-Jen
Published: October 2010

Background and Purpose—

The association between hepatitis C virus (HCV) infection and cerebrovascular disease remains controversial. This study aimed to assess the risk of lethal cerebrovascular diseases associated with chronic HCV infection.

Methods—

In this community-based prospective cohort study, 23 665 residents (aged 30 to 65 years) were enrolled in 1991 to 1992. They were personally interviewed using structured questionnaires and provided blood samples for various serological and biochemical tests at study entry. Serum HCV RNA level and HCV genotype were tested for participants seropositive for antibodies against HCV (anti-HCV). Deaths from cerebrovascular disease during follow-up were ascertained by computerized linkage with National Death Certification profiles from 1991 to 2008 (International Classification of Diseases, 9th Revision 430 to 438). Multivariate-adjusted hazard ratio with 95% CI was estimated for each risk predictor.

Results—

There were 255 cerebrovascular deaths during 382 011 person-years of follow-up. The cumulative risk of cerebrovascular deaths was 1.0% and 2.7% for seronegatives and seropositives of anti-HCV, respectively (
P
<0.001). The hazard ratio (95% CI) of cerebrovascular death was 2.18 (1.50 to 3.16) for anti-HCV seropositives after adjustment for several conventional risk factors of cerebrovascular disease. Compared with participants seronegative for anti-HCV as the referent, the multivariate-adjusted hazard ratio (95% CI) was 1.40 (0.62 to 3.16), 2.36 (1.42 to 3.93), and 2.82 (1.25 to 6.37), respectively, for anti-HCV-seropositive participants with undetectable, low, and high serum levels of HCV RNA (
P
<0.001 for trend). However, no significant association was observed between HCV genotype and cerebrovascular death.

Conclusions—

Chronic HCV infection is an independent risk predictor of cerebrovascular deaths showing a biological gradient of cerebrovascular mortality with increasing serum HCV RNA level.
Picbreeder: A Case Study in Collaborative Evolutionary Exploration of Design Space
Authors: Secretan Jimmy , Beato Nicholas , D'Ambrosio David B. , Rodriguez Adelein , Campbell Adam , Folsom-Kovarik Jeremiah T. , Stanley Kenneth O.
Published: October 2010

For domains in which fitness is subjective or difficult to express formally, interactive evolutionary computation (IEC) is a natural choice. It is possible that a collaborative process combining feedback from multiple users can improve the quality and quantity of generated artifacts. Picbreeder, a large-scale online experiment in collaborative interactive evolution (CIE), explores this potential. Picbreeder is an online community in which users can evolve and share images, and most importantly, continue evolving others' images. Through this process of branching from other images, and through continually increasing image complexity made possible by the underlying neuroevolution of augmenting topologies (NEAT) algorithm, evolved images proliferate unlike in any other current IEC system. This paper discusses not only the strengths of the Picbreeder approach, but its challenges and shortcomings as well, in the hope that lessons learned will inform the design of future CIE systems.
Efficient Markov Chain Monte Carlo Methods for Decoding Neural Spike Trains
Authors: Ahmadian Yashar , Pillow Jonathan W. , Paninski Liam
Published: October 2010

Stimulus reconstruction or decoding methods provide an important tool for understanding how sensory and motor information is represented in neural activity. We discuss Bayesian decoding methods based on an encoding generalized linear model (GLM) that accurately describes how stimuli are transformed into the spike trains of a group of neurons. The form of the GLM likelihood ensures that the posterior distribution over the stimuli that caused an observed set of spike trains is log concave so long as the prior is. This allows the maximum a posteriori (MAP) stimulus estimate to be obtained using efficient optimization algorithms. Unfortunately, the MAP estimate can have a relatively large average error when the posterior is highly nongaussian. Here we compare several Markov chain Monte Carlo (MCMC) algorithms that allow for the calculation of general Bayesian estimators involving posterior expectations (conditional on model parameters). An efficient version of the hybrid Monte Carlo (HMC) algorithm was significantly superior to other MCMC methods for gaussian priors. When the prior distribution has sharp edges and corners, on the other hand, the “hit-and-run” algorithm performed better than other MCMC methods. Using these algorithms, we show that for this latter class of priors, the posterior mean estimate can have a considerably lower average error than MAP, whereas for gaussian priors, the two estimators have roughly equal efficiency. We also address the application of MCMC methods for extracting nonmarginal properties of the posterior distribution. For example, by using MCMC to calculate the mutual information between the stimulus and response, we verify the validity of a computationally efficient Laplace approximation to this quantity for gaussian priors in a wide range of model parameters; this makes direct model-based computation of the mutual information tractable even in the case of large observed neural populations, where methods based on binning the spike train fail. Finally, we consider the effect of uncertainty in the GLM parameters on the posterior estimators.
Modeling Multivariate Time Series on Manifolds with Skew Radial Basis Functions
Authors: Jamshidi Arta A. , Kirby Michael J.
Published: October 2010

We present an approach for constructing nonlinear empirical mappings from high-dimensional domains to multivariate ranges. We employ radial basis functions and skew radial basis functions for constructing a model using data that are potentially scattered or sparse. The algorithm progresses iteratively, adding a new function at each step to refine the model. The placement of the functions is driven by a statistical hypothesis test that accounts for correlation in the multivariate range variables. The test is applied on training and validation data and reveals nonstatistical or geometric structure when it fails. At each step, the added function is fit to data contained in a spatiotemporally defined local region to determine the parameters—in particular, the scale of the local model. The scale of the function is determined by the zero crossings of the autocorrelation function of the residuals. The model parameters and the number of basis functions are determined automatically from the given data, and there is no need to initialize any ad hoc parameters save for the selection of the skew radial basis functions. Compactly supported skew radial basis functions are employed to improve model accuracy, order, and convergence properties. The extension of the algorithm to higher-dimensional ranges produces reduced-order models by exploiting the existence of correlation in the range variable data. Structure is tested not just in a single time series but between all pairs of time series. We illustrate the new methodologies using several illustrative problems, including modeling data on manifolds and the prediction of chaotic time series.
A Framework for Simulating and Estimating the State and Functional Topology of Complex Dynamic Geometric Networks
Authors: Buibas Marius , Silva Gabriel A.
Published: October 2010

We introduce a framework for simulating signal propagation in geometric networks (networks that can be mapped to geometric graphs in some space) and developing algorithms that estimate (i.e., map) the state and functional topology of complex dynamic geometric networks. Within the framework, we define the key features typically present in such networks and of particular relevance to biological cellular neural networks: dynamics, signaling, observation, and control. The framework is particularly well suited for estimating functional connectivity in cellular neural networks from experimentally observable data and has been implemented using graphics processing unit high-performance computing. Computationally, the framework can simulate cellular network signaling close to or faster than real time. We further propose a standard test set of networks to measure performance and compare different mapping algorithms.
Immersive Journalism: Immersive Virtual Reality for the First-Person Experience of News
Authors: de la Peña Nonny , Weil Peggy , Llobera Joan , Spanlang Bernhard , Friedman Doron , Sanchez-Vives Maria V , Slater Mel
Published: October 2010

This paper introduces the concept and discusses the implications of immersive journalism, which is the production of news in a form in which people can gain first-person experiences of the events or situation described in news stories. The fundamental idea of immersive journalism is to allow the participant, typically represented as a digital avatar, to actually enter a virtually recreated scenario representing the news story. The sense of presence obtained through an immersive system (whether a Cave or head-tracked head-mounted displays [HMD] and online virtual worlds, such as video games and online virtual worlds) affords the participant unprecedented access to the sights and sounds, and possibly feelings and emotions, that accompany the news. This paper surveys current approaches to immersive journalism and the theoretical background supporting claims regarding avatar experience in immersive systems. We also provide a specific demonstration: giving participants the experience of being in an interrogation room in an offshore prison. By both describing current approaches and demonstrating an immersive journalism experience, we open a new avenue for research into how presence can be utilized in the field of news and nonfiction.
Haptic and Sound Interface for Shape Rendering
Authors: Bordegoni Monica
Published: October 2010

This paper presents a system for the evaluation of the shape of aesthetic products. The evaluation of shapes is based on characteristic curves, which is a typical practice in the industrial design domain. The system, inspired by characteristic curves, is based on a haptic strip that conforms to a curve that the designer wishes to feel, explore, and analyze by physically touching it. The haptic strip is an innovative solution in the haptics domain, although it has some limitations concerning the domain of curves that can be actually represented. In order to extend this domain and make users feel the various curve features, for example curvature discontinuities, sound has been exploited as an additional information modality.
Relations between Temperature and Residential Natural Gas Consumption in the Central and Eastern United States
Authors: Timmer Reed P. , Lamb Peter J.
Published: October 2010

The increased U.S. natural gas price volatility since the mid-to-late-1980s deregulation generally is attributed to the deregulated market being more sensitive to temperature-related residential demand. This study therefore quantifies relations between winter (November–February; December–February) temperature and residential gas consumption for the United States east of the Rocky Mountains for 1989–2000, by region and on monthly and seasonal time scales. State-level monthly gas consumption data are aggregated for nine multistate subregions of three Petroleum Administration for Defense Districts of the U.S. Department of Energy. Two temperature indices [days below percentile (DBP) and heating degree-days (HDD)] are developed using the Richman–Lamb fine-resolution (∼1° latitude–longitude) set of daily maximum and minimum temperatures for 1949–2000. Temperature parameters/values that maximize DBP/HDD correlations with gas consumption are identified. Maximum DBP and HDD correlations with gas consumption consistently are largest in the Great Lakes–Ohio Valley region on both monthly (from +0.89 to +0.91) and seasonal (from +0.93 to +0.97) time scales, for which they are based on daily maximum temperature. Such correlations are markedly lower on both time scales (from +0.62 to +0.80) in New England, where gas is less important than heating oil, and on the monthly scale (from +0.55 to +0.75) across the South because of low January correlations. For the South, maximum correlations are for daily DBP and HDD indices based on mean or minimum temperature. The percentiles having the highest DBP index correlations with gas consumption are slightly higher for northern regions than across the South. This is because lower (higher) relative (absolute) temperature thresholds are reached in warmer regions before home heating occurs. However, these optimum percentiles for all regions are bordered broadly by surrounding percentiles for which the correlations are almost as high as the maximum. This consistency establishes the robustness of the temperature–gas consumption relations obtained. The reference temperatures giving the highest HDD correlations with gas consumption are lower for the colder northern regions than farther south where the temperature range is truncated. However, all HDD reference temperatures greater than +10°C (+15°C) yield similar such correlations for northern (southern) regions, further confirming the robustness of the findings. This robustness, coupled with the very high correlation magnitudes obtained, suggests that potentially strong gas consumption predictability would follow from accurate seasonal temperature forecasts.
The North Pacific Climate Transitions of the Winters of 1976/77 and 1988/89
Authors: Yeh Sang-Wook , Kang Yune-Jung , Noh Yign , Miller Arthur J.
Published: October 2010

This paper examines characteristic changes in North Pacific sea surface temperature (SST) variability during the boreal winter (December–February) for two subperiods (1956–88 and 1977–2009) during which the 1976/77 and the 1988/89 climate transitions occurred. It is found that the Pacific decadal oscillation (PDO)-like SST variability plays a dominant role in the 1976/77 climate transition, while both the North Pacific Gyre Oscillation (NPGO)-like and PDO-like SST variability contribute to the 1988/89 climate transition. Furthermore, the leading mode changes from PDO-like SST variability during the period 1956–88 to NPGO-like SST variability during the period 1977–2009, indicative of an enhancement of NPGO-like SST variability since 1988. Changes in sea level pressure across the 1976/77 climate transition project strongly onto the Aleutian low pressure system. But sea level pressure changes across the 1988/89 climate transition project primarily onto the North Pacific Oscillation, which is associated with remote changes in the Arctic Oscillation over the polar region as well. This contributes to enhancing the NPGO-like SST variability after 1988. The authors also analyze the output from an ensemble of Tropical Ocean and Global Atmosphere (TOGA) experiments in which the observed SSTs are inserted only at grid points in the tropics between 20°S and 20°N. The results indicate that the changes in the North Pacific atmosphere in the 1976/77 climate transition are mostly due to the tropics, whereas those in the 1988/89 climate transition are not.
The Role of Regional SST Warming Variations in the Drying of Meso-America in Future Climate Projections*
Authors: Rauscher Sara A. , Kucharski Fred , Enfield David B.
Published: October 2010

This paper addresses several hypotheses designed to explain why AOGCM simulations of future climate in the third phase of the Coupled Model Intercomparison Project (CMIP3) feature an intensified reduction of precipitation over the Meso-America (MA) region. While the drying is consistent with an amplification of the subtropical high pressure cells and an equatorward contraction of convective regions due to the “upped ante” for convection in a warmer atmosphere, the physical mechanisms behind the intensity and robustness of the MA drying signal have not been fully explored. Regional variations in sea surface temperature (SST) warming may play a role. First, SSTs over the tropical North Atlantic (TNA) do not warm as much as the surrounding ocean. The troposphere senses a TNA that is cooler than the tropical Pacific, potentially exciting a Gill-type response, increasing the strength of the North Atlantic subtropical high. Second, the warm ENSO-like state simulated in the eastern tropical Pacific could decrease precipitation over MA, as warm ENSO events are associated with drying over MA.

The authors use the International Centre for Theoretical Physics (ICTP) AGCM to investigate the effects of these regional SST warming variations on the projected drying over MA. First, the change of SSTs [Special Report on Emissions Scenarios (SRES) A1B’s Twentieth-Century Climate in Coupled Model (A1B-20C)] in the ensemble average of the CMIP3 models is applied to determine if the ICTP AGCM can replicate the future drying. Then the effects of 1) removing the reduced warming over the TNA, 2) removing the warm ENSO-event-like pattern in the eastern tropical Pacific, and 3) applying uniform SST warming throughout the tropics are tested. The ICTP AGCM can reproduce the general pattern and amount of precipitation over MA. Simulations in which the CMIP3 A1B-20C ensemble-average SSTs are added to climatological SSTs show drying of more than 20% over the MA region, similar to the CMIP3 ensemble average. Replacing the relatively cooler SSTs over the TNA excites a Gill response consistent with an off-equatorial heating anomaly, showing that the TNA relative cooling is responsible for about 16% (31%) of the drying in late spring (early summer). The warm ENSO-like SST pattern over the eastern Pacific also affects precipitation over the MA region, with changes of 19% and 31% in March–June (MMJ) and June–August (JJA), respectively. This work highlights the importance of understanding even robust signals in the CMIP3 future scenario simulations, and should aid in the design and analysis of future climate change studies over the region.
Global Teleconnections in Response to Freshening over the Antarctic Ocean
Authors: Ma Hao , Wu Lixin
Published: October 2010

In this paper, coupled ocean–atmosphere responses to freshening over the Antarctic Ocean are investigated in a fully coupled model with a series of sensitivity experiments. In the model, 1.0 Sv (1 Sv ≡ 106 m3 s−1) of freshwater flux is uniformly imposed over the Antarctic Ocean for 400 yr, while the ocean and atmosphere remain fully coupled both locally and elsewhere. The model explicitly demonstrates that a freshening of the Antarctic Ocean can induce a significant local cooling coupled with an intensification of the westerly winds and expansion of sea ice. Furthermore, the cooling can extend to the entire southern extratropical and tropical oceans coupled with an intensification of southeasterly trades and the equatorial trade winds. Some modest warm anomalies also occur in the northern extratropical oceans, forming a sharp interhemispheric SST contrast.

A series of sensitivity experiments are conducted to understand the mechanisms responsible for transmitting the southern high latitude cooling to the tropics and the Northern Hemisphere. Experimental results demonstrate the important role of the surface coupled wind–evaporation–SST feedback and in turn changes of the subtropical–tropical meridional overturning circulation in conveying the southern high-latitude temperature anomalies to the tropics. The interhemispheric seesaw originates from the tropical–northern extratropical atmospheric teleconnection and is sustained by the subductive process of Antarctic subsurface warming. The Atlantic meridional overturning circulation is intensified in the first few decades of the freshwater forcing over the Antarctic Ocean because of a shutdown of the Antarctic deep convection, but it subsequently decreases because of the spreading of the fresh anomalies from the Southern Ocean to the Northern Ocean.
Relationships between Extratropical Sea Level Pressure Variations and the Central Pacific and Eastern Pacific Types of ENSO
Authors: Yu Jin-Yi , Kim Seon Tae
Published: October 2010

This study examines the linkages between leading patterns of interannual sea level pressure (SLP) variability over the extratropical Pacific (20°–60°N) and the eastern Pacific (EP) and central Pacific (CP) types of El Niño–Southern Oscillation (ENSO). The first empirical orthogonal function (EOF) mode of the extratropical SLP anomalies represents variations of the Aleutian low, and the second EOF mode represents the North Pacific Oscillation (NPO) and is characterized by a meridional SLP anomaly dipole with a nodal point near 50°N. It is shown that a fraction of the first SLP mode can be excited by both the EP and CP types of ENSO. The SLP response to the EP type is stronger and more immediate. The tropical–extratropical teleconnection appears to act more slowly for the CP ENSO. During the decay phase of EP events, the associated extratropical SLP anomalies shift from the first SLP mode to the second SLP mode. As the second SLP mode grows, subtropical SST anomalies are induced beneath via surface heat flux anomalies. The SST anomalies persist after the peak in strength of the second SLP mode, likely because of the seasonal footprinting mechanism, and lead to the development of the CP type of ENSO. This study shows that the CP ENSO is an extratropically excited mode of tropical Pacific variability and also suggests that the decay of an EP type of ENSO can lead to the onset of a CP type of ENSO with the aid of the NPO. This extratropical linking mechanism appears to be at work during the 1972, 1982, and 1997 strong El Niño events, which were all EP events and were all followed by strong CP La Niña events after the NPO was excited in the extratropics. This study concludes that extratropical SLP variations play an important role in exciting the CP type of ENSO and in linking the transitions from the EP to CP events.
Ocean Heat Transport as a Cause for Model Uncertainty in Projected Arctic Warming
Authors: Mahlstein Irina , Knutti Reto
Published: October 2010

The Arctic climate is governed by complex interactions and feedback mechanisms between the atmosphere, ocean, and solar radiation. One of its characteristic features, the Arctic sea ice, is very vulnerable to anthropogenically caused warming. Production and melting of sea ice is influenced by several physical processes. The authors show that the northward ocean heat transport is an important factor in the simulation of the sea ice extent in the current general circulation models. Those models that transport more energy to the Arctic show a stronger future warming, in the Arctic as well as globally. Larger heat transport to the Arctic, in particular in the Barents Sea, reduces the sea ice cover in this area. More radiation is then absorbed during summer months and is radiated back to the atmosphere in winter months. This process leads to an increase in the surface temperature and therefore to a stronger polar amplification. The models that show a larger global warming agree better with the observed sea ice extent in the Arctic. In general, these models also have a higher spatial resolution.

These results suggest that higher resolution and greater complexity are beneficial in simulating the processes relevant in the Arctic and that future warming in the high northern latitudes is likely to be near the upper range of model projections, consistent with recent evidence that many climate models underestimate Arctic sea ice decline.
Future Impact of Differential Interbasin Ocean Warming on Atlantic Hurricanes
Authors: Lee Sang-Ki , Enfield David B. , Wang Chunzai
Published: October 2010

Global climate model simulations forced by future greenhouse warming project that the tropical North Atlantic (TNA) warms at a slower rate than the tropical Indo-Pacific in the twenty-first century, consistent with their projections of a weakened Atlantic thermohaline circulation. Here, an atmospheric general circulation model is used to advance a consistent physical rationale that the suppressed warming of the TNA increases the vertical wind shear and static stability aloft in the main development region (MDR) for Atlantic hurricanes, and thus decreases overall Atlantic hurricane activity in the twenty-first century. A carefully designed suite of model experiments illustrates that the preferential warming of the tropical Indo-Pacific induces a global average warming of the tropical troposphere, via a tropical teleconnection mechanism, and thus increases atmospheric static stability and decreases convection over the suppressed warming region of the TNA. The anomalous diabatic cooling, in turn, forces the formation of a stationary baroclinic Rossby wave northwest of the forcing region, consistent with Gill’s simple model of tropical atmospheric circulations, in such a way as to induce a secular increase of the MDR vertical wind shear. However, a further analysis indicates that the net effect of future greenhouse warming on the MDR vertical wind shear is less than the observed multidecadal swing of the MDR vertical wind shear in the twentieth century. Thus, it is likely that the Atlantic multidecadal oscillation will still play a decisive role over the greenhouse warming in the fate of Atlantic hurricane activity throughout the twenty-first century under the assumption that the twenty-first-century changes in interbasin SST difference, projected by the global climate model simulations, are accurate.
Observed Ocean Variability in the Mindanao Dome Region
Authors: Kashino Yuji , Ishida Akio , Hosoda Shigeki
Published: October 2010

Ocean variations at semiannual, annual, and interannual time scales in the Mindanao Dome (MD) region of the southern Philippine Sea were examined using data derived from underwater sensors on Triangle Trans-Ocean Buoy Network (TRITON) buoys at 8°N, 137°E; 5°N, 137°E; and 8°N, 130°E. Annual signal dominated above 300-m depth in the MD region. At 5°N, 137°E, saline water exceeding 35 psu was observed at 100–200-m depth from boreal winter to spring, seemingly associated with the meridional migration of the North Equatorial Countercurrent during these seasons. Thermocline ascent, probably related to the MD, was also observed from boreal winter to spring. An important mechanism of the annual variation of the MD at 5°N seems to be the annual variability of local wind, as mentioned in past studies. However, annual variability at 8°N seems to be due to Rossby waves originating west of 150°W rather than to local wind effects. Semiannual variation was also observed, with its amplitude reaching 40%–70% of the annual signal. With regard to interannual variability, ocean variation on the time scale of the El Niño–Southern Oscillation (ENSO) was seen; upper heat content (above 300-m depth) in the Mindanao Dome region decreased during the 2002–03 and 2006–07 El Niño periods and increased between those periods. Increasing upper heat content in this region after 2005 was probably associated with large negative anomalies of Ekman pumping (downwelling) that appeared from 2005 to 2006 east of 150°E and north of 5°N.
Patterns of Land Surface Errors and Biases in the Global Forecast System
Authors: Werth David , Garrett Alfred
Published: October 2010

One year’s worth of Global Forecast System (GFS) predictions of surface meteorological variables (wind speed, air temperature, dewpoint temperature, sea level pressure) are validated for land-based stations over the entire planet for forecasts extending from 0 h into the future (an analysis) to 7 days. Approximately 12 000 surface stations worldwide were included in this analysis. Root-mean-square errors (RMSEs) increased as the forecast period increased from 0 to 36 h, but the initial RMSEs were almost as large as the 36-h forecast RMSEs for all variables. Typical RMSEs were 3°C for air temperature, 2–3 mb for sea level pressure, 3.5°C for dewpoint temperature, and 2.5 m s−1 for wind speed.

An analysis of the biases at each station shows that the biggest errors are associated with mountain ranges and other areas of steep topography, with land–sea contrasts also playing a role. When the error is decomposed into the bias, variance, and correlation terms, the large initial RMSEs for the 0-h forecasts are seen to be due to a large forecast bias (which persisted into the longer forecasts) with errors in forecast correlation also making a large contribution.

A validation of two subdomains showed results similar to the global validation, but the dependence of the biases on the forecast time was clearer. Finally, the RMSE values climb as forecasts go out when validated out to a period of 7 days as the correlation error term grows.
The AROME-France Convective-Scale Operational Model
Authors: Seity Y. , Brousseau P. , Malardel S. , Hello G. , Bénard P. , Bouttier F. , Lac C. , Masson V.
Published: October 2010

After six years of scientific, technical developments and meteorological validation, the Application of Research to Operations at Mesoscale (AROME-France) convective-scale model became operational at Météo-France at the end of 2008. This paper presents the main characteristics of this new numerical weather prediction system: the nonhydrostatic dynamical model core, detailed moist physics, and the associated three-dimensional variational data assimilation (3D-Var) scheme. Dynamics options settings and variables are explained. The physical parameterizations are depicted as well as their mutual interactions. The scale-specific features of the 3D-Var scheme are shown. The performance of the forecast model is evaluated using objective scores and case studies that highlight its benefits and weaknesses.
The devil is in the details
Authors: Gleddie Doug L
Published: October 2010

Objective: Guidelines from a variety of jurisdictions for the health-promoting schools (HPS) approach include healthy school policy as a critical element. Research also supports the importance of policy; however, there seems to be a lack of information on how to develop and implement policy. The article examines the processes involved in one school division’s development and implementation of healthy school policy.

Design: The study emerged from the Battle River Project, a multilevel partnership designed to explore the efficacy of implementing HPS at a school division level. The project intervention involved support for schools, a division-level steering committee, and a framework for implementation.

Setting: The Battle River School Division is located in Alberta, Canada, and serves both rural and urban school communities. The study involved 21 of the 36 schools in the division and was initiated by the Ever Active Schools programme.

Method: Development and implementation of policy and procedure were examined using case study methodology. Data gathered included interviews, focus groups, documents and observation.

Results: Four primary themes were revealed through data analysis. Perceptions and misconceptions; bottom–up/top–down; flexible rigidity; and the way we do business.

Conclusion: The process of developing and implementing healthy school policy can be streamlined by planning for clear communication, involving all stakeholders, and by embedding health into the structures of a school jurisdiction.
Our Women Must Return Home: Institutionalized Patriarchy in Colonial Central Nyanza District, 1945-1963
Authors: Okuro Samwel Ong'wen
Published: October 2010

Colonial policies and practices were very instrumental in the creation of the Luo Diaspora. This Diaspora extended far beyond the physical and cultural boundaries of Central Nyanza as was constituted by the colonial administration. To colonial officials, this Diaspora represented ‘detribalized natives’ responsible for social decay and immorality in the colonial townships. Similarly, to the male elders in the rural areas, this Diaspora was an affront towards destabilizing tribal authority and sanctions, which governed Luo moral order, Luo marriage, and Luo identity as it existed prior to colonialism. This article uses patriarchy as an analytical framework to understand how male elders and colonial officials collaborated to assert control over young women under suspicion of prostitution. The article argues that the Ramogi African Welfare Association (RAWA) was a post-war patriarchal institution which was used by male elders, with the encouragement of the colonial officials, to intimidate, harass and repatriate young women seeking wage employment within the emerging colonial townships. In this article, I use archival and field data gathered from Central Nyanza between 1999 and 2002 to illustrate how institutionalized patriarchy threatened many women and young girls seeking to migrate to colonial towns in order to exploit the limited economic and social opportunities that colonialism provided.
Federalism and State Disintegration - United Pakistan, 1947-1971: Some Historical Lessons for Afghanistan and Iraq
Authors: Nuruzzaman Mohammed
Published: October 2010

Multiethnic, multilingual and socially divided large states usually, though not always willingly, prefer a federal system of government to build state institutions and promote national integration. Recently, there has been a surge in interest in federalism following the US-led invasions of Afghanistan in October 2001 and Iraq in March 2003. There are, however, both successes and failures in federal endeavors. This article analyzes the underlying reasons behind United Pakistan’s (1947—1971) choice of federalism right after its independence in 1947, probes the complex factors that eventually led to the disintegration of Pakistan in 1971, and finally highlights the historical lessons the failure of federalism in United Pakistan holds for Afghanistan and Iraq which are ethnically, socially, culturally and politically diverse and share many of the characteristics of United Pakistan. It argues that both Afghanistan and Iraq have much to learn from failed federal experiment in United Pakistan if they wish to avert their possible disintegration in future.
Mean Consumption, Poverty and Inequality in Rural India in the 60th Round of the National Sample Survey
Authors: Jha Raghbendra , Gaiha Raghav , Sharma Anurag
Published: October 2010

This article reports on mean consumption, poverty (all three FGT measures) and inequality during 2004 for rural India using National Sample Survey (NSS) data for the 60th Round. Mean consumption at the national level is much higher than the poverty line. However, the Gini coefficient is higher than in recent earlier rounds. The headcount ratio is 22.9 per cent. Mean consumption, all three measures of poverty and the Gini coefficient are computed at the level of 20 states and 63 agro-climatic zones in these 20 states. It is surmised that despite impressive growth rates deprivation is pervasive, pockets of severe poverty persist, and inequality is rampant.
Analysing Political Subjectivities: Naming the Post-developmental State in Africa Today
Authors: Neocosmos Michael
Published: October 2010

Politics, whether that of the state or that constituted beyond the state, must be analysed as thought, as subjectivity. This article proposes to do so in connection with state politics in Africa since independence. It consists of a brief theoretical justification for such a perspective, a methodological stress on the process of elucidating the names around which such politics is deployed, and an application of these conceptions to the politics of the post-colonial African state. It shows that two different forms of state can be elucidated, namely a ‘developmental state’ form in which parties play a subjective role of mobilizing popular political subjectivities within the state, and a ‘post-developmental’ state form, hegemonic today, in which a consensus is established between state and civil society organizations. In either case the sites of alternative politics to these state political sequences which arise beyond state subjectivity are briefly elucidated.
Transfer of L1 Cohesive Devices and Transition Words into L2 Academic Texts: The Case of Arab Students
Authors: Mohamed-Sayidina Aisha
Published: October 2010

This study claims that Arab ESL students writing in English transfer L1 rhetorical modes of text organization into their English compositions. Fifty academic research papers were analysed in terms of the transition words and cohesive devices used, on the assumption that differences at the level of these language forms reflect differences at the higher level of rhetorical text organization. The hypothesis is stated in two sub-parts. In the first, it is claimed that, as in L1 native texts, the students’ English compositions use a predominantly additive mode of propositional development. In the second part, it is claimed that, as in L1 native texts, propositional connectivity is established in the students’ compositions largely through repetition of the same noun, as opposed to the use of grammatical cohesion. The results of the analysis provide strong statistical support for both sub-parts of the hypothesis. Overall, additive transition words are more commonly used in the compositions than other types of transition words. Further, the repetition of the same noun is statistically more frequent as a cohesive device than grammatical cohesion. An attempt is made to explain the rhetorical modes used in the students’ compositions as well as in native Arabic texts with reference to Arab culture.