bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a High-Throughput Cloning Strategy for Characterization of Acinetobacter baumannii Drug Transporter Proteins
Authors: Eijkelkamp Bart A. , Hassan Karl A. , Paulsen Ian T. , Brown Melissa H.
Published: July 2011

Heterologous expression of membrane proteins in Escherichia coli often requires optimization to overcome problems with toxicity of the recombinant protein to the host cell. A number of Gateway-based destination vectors were constructed to investigate expression of membrane proteins using a high-throughput approach. These vectors were tested using putative drug transporter proteins from the multidrug and toxic compound extrusion (MATE) family and the resistance-nodulation-cell division superfamily encoded by the human pathogen Acinetobacter baumannii. Active transport of antibiotics and antiseptics mediated by efflux proteins contributes to the high level of multidrug resistance observed in A. baumannii. Substrates for 4 of the 5 putative efflux proteins investigated were identified using the expression vectors designed in this study. Additionally, a Gateway-based suicide vector was designed for construction of specific A. baumannii insertion disruption mutants. This knockout cloning strategy was tested and shown to be successful in inactivating AbeM4, a putative MATE family protein. Therefore, we have shown that the Gateway-based vectors constructed in this study are versatile tools that can be used for manipulation and characterization of membrane proteins.
Nuclear Factor of Activated T Cells 5 Regulates Vascular Smooth Muscle Cell Phenotypic Modulation
Authors: Halterman Julia A. , Kwon H. Moo , Zargham Ramin , Bortz Pamela D. Schoppee , Wamhoff Brian R.
Published: July 2011

Objective—

The tonicity-responsive transcription factor, nuclear factor of activated T cells 5 (NFAT5/tonicity enhancer binding protein [TonEBP]), has been well characterized in numerous cell types; however, NFAT5 function in vascular smooth muscle cells (SMCs) is unknown. Our main objective was to determine the role of NFAT5 regulation in SMCs.

Methods and Results—

We showed that NFAT5 is regulated by hypertonicity in SMCs and is upregulated in atherosclerosis and neointimal hyperplasia. RNAi knockdown of NFAT5 inhibited basal expression of several SMC differentiation marker genes, including smooth muscle α actin (SMαA). Bioinformatic analysis of SMαA revealed 7 putative NFAT5 binding sites in the first intron, and chromatin immunoprecipitation analysis showed NFAT5 enrichment of intronic DNA. Overexpression of NFAT5 increased SMαA promoter-intron activity, which requires an NFAT5
cis
element at +1012, whereas dominant-negative NFAT5 decreased SMαA promoter-intron activity. Because it is unlikely that SMCs experience extreme changes in tonicity, we investigated other stimuli and uncovered 2 novel NFAT5-inducing factors: angiotensin II, a contractile agonist, and platelet-derived growth factor-BB (PDGF-BB), a potent mitogen in vascular injury. Angiotensin II stimulated NFAT5 translocation and activity, and NFAT5 knockdown inhibited an angiotensin II-mediated upregulation of SMαA mRNA. PDGF-BB increased NFAT5 protein, and loss of NFAT5 inhibited PDGF-BB-induced SMC migration.

Conclusion—

We have identified NFAT5 as a novel regulator of SMC phenotypic modulation and have uncovered the role of NFAT5 in angiotensin II-induced SMαA expression and PDGF-BB-stimulated SMC migration.
Nuclear Effects of G-Protein Receptor Kinase 5 on Histone Deacetylase 5–Regulated Gene Transcription in Heart Failure
Authors: Zhang Yan , Matkovich Scot J. , Duan Xiujun , Gold Jessica I. , Koch Walter J. , Dorn Gerald W.
Published: July 2011

Background—

G-protein receptor kinases (GRKs) modulate cardiac β-adrenergic signaling. GRK5 is upregulated in heart failure, and a gain-of-function polymorphism substituting leucine for wild-type glutamine at amino acid 41 (GRK5-Leu41) is associated with improved outcomes in heart failure and hypertension. GRK5 is distinguished by partial nuclear localization and class II histone deacetylases (HDAC) kinase activity that is postulated to regulate Gαq-stimulated cardiac gene expression.

Methods and Results—

We used in vitro tissue culture and in vivo mouse compound genetic models to examine the effects of GRK5 on HDAC phosphorylation, nucleo-cytoplasmic HDAC transport, and Gαq-dependent transcriptional regulation. In vitro, GRK5 stimulated HDAC5 nuclear export only in the context of Gαq signaling stimulated by angiotensin II. GRK5-Gln41 and Leu41 were similar inducers of HDAC5 nucleo-cytoplasmic shuttling. In vivo, GRK5-Gln41 and-Leu41 partitioned equally to nuclear and nonnuclear myocardial fractions. GRK5 increased cardiac HDAC5 phosphorylation and reversed the increase in nuclear HDAC5 content seen with cardiomyocyte-autonomous Gαq overexpression. Deep RNA sequencing showed few changes in gene expression induced by GRK5 overexpression or ablation alone, but GRK5 overexpression normalized steady-state expression levels of 48% (96 of 200) of all Gαq down-regulated mRNAs.

Conclusions—

GRK5 is a transcriptional modifier of a subset of Gαq-downregulated genes, acting in opposition to the pathological effects of Gαq and normalizing levels of these transcripts. This transcriptional coregulator effect may act in concert with β-adrenergic receptor desensitization to protect against heart failure decompensation.
Wnt/β-Catenin Signaling Maintains the Mesenchymal Precursor Pool for Murine Sinus Horn Formation
Authors: Norden Julia , Greulich Franziska , Rudat Carsten , Taketo Makoto Mark , Kispert Andreas
Published: July 2011

Rationale:

Canonical (β-catenin [
Ctnnb1
]-dependent) wingless-related MMTV integration site (Wnt) signaling plays an important role in the development of second heart field–derived structures of the heart by regulating precursor cell proliferation. The signaling pathways that regulate the most posterior elongation of the heart, that is, the addition of the systemic venous return from a
Tbx18
+
precursor population, have remained elusive.

Objective:

To define the role of
Ctnnb1
-dependent Wnt signaling in the development of the cardiac venous pole.

Methods and Results:

We show by in situ hybridization analysis that Wnt pathway components are expressed and canonical Wnt signaling is active in the developing sinus horns. We analyzed sinus horn (
Tbx18

cre

)-specific
Ctnnb1
loss- and gain-of-function mutant embryos. In
Ctnnb1
-deficient embryos, the dorsal part of the sinus horns is not myocardialized but consists of cells with at least partial fibroblast identity; the sinoatrial node is unaffected. Stabilization of
Ctnnb1
in this domain results in the formation of undifferentiated cell aggregates. Analysis of cellular changes revealed a role of canonical Wnt signaling in proliferation of the
Tbx18
+
mesenchymal progenitor cell population.

Conclusions:

Wnt/β-catenin signaling maintains the
Tbx18
+
Nkx2–5
−
mesenchymal precursor pool for murine sinus horn formation.
Impact of Obesity on Stroke Outcome After Intravenous Thrombolysis
Authors: Sarikaya Hakan , Elmas Firat , Arnold Marcel , Georgiadis Dimitrios , Baumgartner Ralf W.
Published: July 2011

Background and Purpose—

Obesity is an established risk factor for stroke and has reached epidemic proportions. However, its impact on intravenous thrombolysis applied for acute ischemic stroke is not well known. We aimed to compare the clinical outcome and safety after intravenous thrombolysis in obese (body mass index ≥30 kg/m
2
) and nonobese (body mass index <30 kg/m
2
) patients with ischemic stroke.

Methods—

Data of 304 consecutive patients with stroke (251 nonobese and 53 obese) treated with intravenous thrombolysis were studied. We assessed the rate of favorable outcome (modified Rankin Scale score 0 or 1), mortality, and symptomatic intracranial hemorrhage in the 2 groups.

Results—

Obese patients presented more often with diabetes mellitus (30.2% versus 12.4%,
P
<0.01) and arterial hypertension (77.4% versus 61.4%,
P
=0.03) as compared with their nonobese counterparts. At 3 months, the rate of favorable outcome was lower in obese compared with nonobese patients (50.9% versus 68.1%,
P
=0.02). More obese than nonobese patients died (13.2% versus 4.0%,
P
=0.01), whereas the rate of symptomatic intracranial hemorrhage was similar in the 2 groups (1.9% versus 1.6%,
P
=1.0). After multivariable adjustment, obesity still remained an independent predictor of unfavorable outcome (
P
=0.04) and mortality (
P
=0.04).

Conclusions—

Our data indicate that obesity is an independent predictor of unfavorable clinical outcome and mortality in acute ischemic stroke treated with intravenous thrombolysis.
Low Body Temperature Does Not Compromise the Treatment Effect of Alteplase
Authors: Lees Jennifer S. , Mishra Nishant K. , Saini Monica , Lyden Patrick D. , Shuaib Ashfaq
Published: July 2011

Background and Purpose—

Hypothermia is neuroprotective in ischemic stroke models. The influence of baseline body temperature on outcomes after thrombolytic therapy is unclear. We examined outcomes after alteplase treatment across baseline body temperature for patients with ischemic stroke in data held within the Virtual International Stroke Trials Archive (VISTA; 1998 to 2007).

Methods—

We collated data on age, baseline severity (National Institutes of Health Stroke Scale), and 90-day modified Rankin Scale score on patients presenting with acute ischemic stroke. We compared 90-day modified Rankin Scale score between thrombolyzed and nonthrombolyzed comparators across baseline body temperature. We report age and baseline National Institutes of Health Stroke Scale-adjusted Cochran-Mantel-Haenszel probability value and proportional OR with 95% CI for improved modified Rankin Scale distribution. We report temperature profiles over 72 hours after stroke by treatment group.

Results—

Rankin data were available for 5586 patients with acute ischemic stroke in VISTA (1980 received alteplase). Age and baseline severity were similar (age 68.0±13.0 years versus 69.9±12.3 years, National Institutes of Health Stroke Scale 14.2±5.2 versus 13.0±5.6). Alteplase was associated with improved outcome (OR, 1.49; 95% CI, 1.35 to 1.65,
P
<0.0001). Alteplase treatment effect was not associated with baseline temperature (
P
=0.14). Point estimates showed benefit of alteplase treatment across 35.5°C to 37.5°C but showed a negative trend >37.5°C. Alteplase did not influence temperature profiles over 72 hours after stroke.

Conclusions—

There is no evidence of influence of body temperature on alteplase treatment response. These results are reassuring that low temperatures across a physiological range do not compromise therapeutic effect of alteplase.
The Prognostic Impact of Soluble Apoptosis-Stimulating Fragment on Mortality in Patients With Carotid Atherosclerosis
Authors: Hoke Matthias , Schillinger Martin , Zorn Gerlinde , Wonnerth Anna , Amighi Jasmin , Mlekusch Wolfgang , Speidl Walter , Maurer Gerald , Koppensteiner Renate , Minar Erich , Wojta Johann , Niessner Alexander
Published: July 2011

Background and Purpose—

Markers of apoptosis are associated with cardiovascular disease. The soluble apoptosis-stimulating fragment (sFAS) was found to be a predictor for outcome in patients with heart failure, but its importance in patients with atherosclerotic disease has not been fully understood as yet. The aim of the present study was to investigate the impact of sFAS on all-cause and cardiovascular mortality in patients with atherosclerosis in the carotid arteries.

Methods—

We studied 981 of 1286 consecutive patients with neurological asymptomatic carotid atherosclerosis as evaluated by duplex Doppler sonography. Patients were prospectively followed for long-term all-cause and cardiovascular mortality.

Results—

During a median follow-up of 6.2 years (interquartile range, 5.9 to 6.6 years), a total of 250 deaths (25.5%), including 165 (66%) cardiovascular deaths, were recorded. The risk for all-cause and for cardiovascular mortality, respectively, increased significantly with sFAS concentrations (
P
<0.001). The hazard ratio for all-cause death was elevated by 2.3-fold (
P
<0.001) and for cardiovascular death by 2.4-fold (
P
<0.001) in patients within the highest quintile of sFAS compared with patients within the lowest quintile, respectively. Results remained significant after adjustment for potential confounders and established cardiovascular risk factors, including high-sensitivity C-reactive protein. Patients with high sFAS but low high-sensitivity C-reactive protein had a comparable survival rate with those with elevated high-sensitivity C-reactive protein only (
P
=0.50).

Conclusions—

Markers of apoptosis, as measured by sFAS, were found to be independent risk predictors for death in patients with atherosclerotic disease in the carotid arteries.
Activated Leukocyte Cell Adhesion Molecule and Prognosis in Acute Ischemic Stroke
Authors: Smedbakken Linda , Jensen Jesper K. , Hallén Jonas , Atar Dan , Januzzi James L. , Halvorsen Bente , Aukrust Pål , Ueland Thor
Published: July 2011

Background and Purpose—

Biomarkers predicting mortality and functional outcome in stroke may be clinically helpful in identification of patients likely to benefit from intervention. Activated leukocyte cell adhesion molecule (ALCAM) is upregulated during neuroinflammation; we investigated whether ALCAM concentrations are associated with long-term mortality after ischemic stroke.

Methods—

In 244 patients with acute ischemic stroke (age 69±13 years), samples of ALCAM were obtained serially from presentation to Day 5 and after 6 months. Patients with overt ischemic heart disease and atrial fibrillation were excluded. The patients were followed for 47 months with all-cause and cardiovascular mortality as end points.

Results—

At follow-up, 72 patients (29%) had died, 43 due to cardiovascular causes. Patients with ALCAM in the fourth quartile (>46.8 ng/mL) at admission had a significantly poorer survival rate on univariate analysis (
P
<0.001); other time points did not add further but provided similar prognostic information. In multivariate analysis, after adjustment for age, stroke severity, C-reactive protein levels, troponin T levels, and heart and/or renal failure, ALCAM levels above the fourth quartile remained an independent predictor of long-term mortality (adjusted hazard ratio, 2.05; 95% CI, 1.11 to 3.76;
P
=0.021) and cardiovascular mortality (adjusted hazard ratio, 2.54; 95% CI, 1.06 to 6.07;
P
=0.028).

Conclusions—

ALCAM levels measured at admission of acute ischemic stroke are associated with long-term mortality.
Efficacy of Intravenous Tissue-Type Plasminogen Activator in Central Retinal Artery Occlusion
Authors: Chen Celia S. , Lee Andrew W. , Campbell Bruce , Lee Tien , Paine Mark , Fraser Clare , Grigg John , Markus Romesh
Published: July 2011

Background and Purpose—

Central retinal artery occlusion is caused by a platelet-fibrin thrombus or embolic occlusion and is a stroke of the eye. Observational studies suggest that thrombolytics may restore ocular perfusion and visual function. We hypothesized that intravenous tissue-type plasminogen activator (tPA) administered within 24 hours of symptom onset might restore ocular perfusion and visual function.

Methods—

A placebo-controlled, randomized trial of intravenous tPA versus intravenous saline was performed in patients with clinically defined central retinal artery occlusion within 24 hours of symptom onset. tPA was administered at a total dose of 0.9 mg/kg, with 10% given as a 1-minute bolus and the remainder over 1 hour. An improvement of visual acuity of 3 lines or more was considered significant.

Results—

Twenty-five percent (2 of 8) of the tPA group experienced the primary outcome at 1 week after tPA versus none of the placebo group. One patient had an intracranial hemorrhage. The visual acuity improvement of these 2 patients was not sustained at 6 months. In both patients, tPA was administered within 6 hours of symptom onset.

Conclusions—

Although essentially a negative study, it does add to the evidence base of reperfusion in central retinal artery occlusion by showing that the time window for intervention is likely to be <6 hours. Reocclusion is a potential problem and may require adjuvant anticoagulation. Future studies should concentrate on determining the efficacy of thrombolytics in the <6-hour time window.

Clinical Trial Registration—

URL:
http://www.anzctr.org.au
. Unique identifier: 83102.
The Montreal Cognitive Assessment
Authors: Cumming Toby B. , Bernhardt Julie , Linden Thomas
Published: July 2011

Background and Purpose—

Cognitive function is often ignored in stroke research trials. The brief Montreal Cognitive Assessment (MoCA) may be sensitive to stroke-related cognitive deficits.

Methods—

We evaluated the feasibility of administering the MoCA at 3 months in a large stroke trial (A Very Early Rehabilitation Trial [AVERT]).

Results—

Data (blinded to intervention group) are presented for 294 patients with mean age of 70.6 years (SD, 12.8); 220 (75%) completed the MoCA, 54 (18%) had missing data, and 20 (7%) had died. Of those surviving to 3 months, the MoCA was completed by 87% with mild stroke, 79% with moderate stroke, and 67% with severe stroke on admission. Mean MoCA score was 21.1 (SD 7.5) out of 30; only 78 of 220 (35%) patients attained the “normal” cutoff (≥26).

Conclusions—

The MoCA is a feasible global cognitive screening tool in stroke trials.

Clinical Trial Registration—

URL:
www.anzctr.org.au/trial_view.aspx?ID=1266
. Unique identifier: ACTRN12606000185561.
Growth and Optimality in Network Evolution
Authors: Brede Markus
Published: July 2011

We investigate networks whose evolution is governed by the interaction of a random assembly process and an optimization process. In the first process, new nodes are added one at a time and form connections to randomly selected old nodes. In between node additions, the network is rewired to minimize its path length. For time scales at which neither the assembly nor the optimization processes are dominant, we find a rich variety of complex networks with power law tails in the degree distributions. These networks also exhibit nontrivial clustering, a hierarchical organization, and interesting degree-mixing patterns.
Information Dynamics in Small-World Boolean Networks
Authors: Lizier Joseph T. , Pritam Siddharth , Prokopenko Mikhail
Published: July 2011

Small-world networks have been one of the most influential concepts in complex systems science, partly due to their prevalence in naturally occurring networks. It is often suggested that this prevalence is due to an inherent capability to store and transfer information efficiently. We perform an ensemble investigation of the computational capabilities of small-world networks as compared to ordered and random topologies. To generate dynamic behavior for this experiment, we imbue the nodes in these networks with random Boolean functions. We find that the ordered phase of the dynamics (low activity in dynamics) and topologies with low randomness are dominated by information storage, while the chaotic phase (high activity in dynamics) and topologies with high randomness are dominated by information transfer. Information storage and information transfer are somewhat balanced (crossed over) near the small-world regime, providing quantitative evidence that small-world networks do indeed have a propensity to combine comparably large information storage and transfer capacity.
Fisher Information at the Edge of Chaos in Random Boolean Networks
Authors: Wang X. Rosalind , Lizier Joseph T. , Prokopenko Mikhail
Published: July 2011

We study the order-chaos phase transition in random Boolean networks (RBNs), which have been used as models of gene regulatory networks. In particular we seek to characterize the phase diagram in information-theoretic terms, focusing on the effect of the control parameters (activity level and connectivity). Fisher information, which measures how much system dynamics can reveal about the control parameters, offers a natural interpretation of the phase diagram in RBNs. We report that this measure is maximized near the order-chaos phase transitions in RBNs, since this is the region where the system is most sensitive to its parameters. Furthermore, we use this study of RBNs to clarify the relationship between Shannon and Fisher information measures.
Modular Random Boolean Networks
Authors: Poblanno-Balp Rodrigo , Gershenson Carlos
Published: July 2011

Random Boolean networks (RBNs) have been a popular model of genetic regulatory networks for more than four decades. However, most RBN studies have been made with random topologies, while real regulatory networks have been found to be modular. In this work, we extend classical RBNs to define modular RBNs. Statistical experiments and analytical results show that modularity has a strong effect on the properties of RBNs. In particular, modular RBNs have more attractors, and are closer to criticality when chaotic dynamics would be expected, than classical RBNs.
The Evolution of Cooperation on Correlated Payoff Landscapes
Authors: Brede Markus
Published: July 2011

We study the evolution of cooperation in the prisoner's dilemma game on time-invariant heterogeneous payoff landscapes on regular and heterogeneous networks. Correlations in the landscape structure and their implications for the evolution of cooperation are investigated. On regular networks we find that negatively and neutrally correlated payoff landscapes strongly enhance cooperation, while positively correlated landscapes may suppress the evolution of cooperation. On heterogeneous networks, cooperation is facilitated if payoff stochasticity is positively correlated with network heterogeneity and may be suppressed otherwise.
Climate Change Bandwagoning: The Impacts of Strategic Linkages on Regime Design, Maintenance, and Death
Authors: Jinnah Sikina
Published: July 2011

The entrée of climate change politics to the center stage of international relations has been accompanied by broad range of strategic linkages, which have produced various institutional interactions. This special issue takes stock of the wide range of ways that international regimes are strategically linked to climate change politics. We do this with a view to better understand both how climate change is shaping the global environmental political landscape, and is being shaped itself through strategic linkages to regimes both within (i.e. forests, biodiversity, fisheries, and desertification) and beyond (i.e. security and human rights) the environmental realm. The contributions that make up this special issue explore when, how, and by whom regime linkages should be pursued, how linkage politics are affecting regime development and function, and in turn how these changes are shaping the evolution of global environmental politics and problem solving writ large.
Issue-linkages to Climate Change Measured through NGO Participation in the UNFCCC
Authors: Cabré Miquel Muñoz
Published: July 2011

NGOs comprise over half the cumulative number of delegates attending the United Nations Framework Convention on Climate Change (UNFCCC) Conference of the Parties (COP) for the 1995–2009 period. These NGOs represent a wide array of issues, including sustainable development, business, and higher education, to name just a few. Based on UNFCCC publicly available participation statistics, this article analyzes NGO participation from a quantitative issue-based perspective, and compares the results with the relevant conclusions drawn by the other contributors to this special issue. The findings of this analysis confirm informed expectations about issue-driven NGO participation. In particular, three main findings are that: (1) environment and conservation, academic, business, and energy NGOs dominate civil society participation in the UNFCCC; (2) UNFCCC constituencies do not adequately capture the range of issues addressed by observer NGOs; and (3) since 2007, NGO participation has sig-nificantly increased and diversified.
Climate Change and Global Fisheries Management: Linking Issues to Protect Ecosystems or to Save Political Interests?
Authors: Axelrod Mark
Published: July 2011

This article explores the conditions under which regional fisheries management organizations (RFMOs) adopt climate actions. I test a series of hypotheses to explain when RFMOs move beyond their classic management approaches—assignment of property rights, catch limits, and gear restrictions—to include climate change in their research and management plans. I introduce a new data set that compares fisheries-climate linkages since 1992 in all available RFMO annual reports and meeting minutes. The analysis reveals a series of patterns surrounding linkage politics in RFMOs. Importantly, this study finds that climate linkages in RFMOs do not simply follow scientific knowledge or regional climate vulnerability. Instead, climate action coincides with member country efforts to avoid catch regulations, and secretariat efforts to exhibit organizational relevance.
Long-Term Wind Speed Trends over Australia
Authors: Troccoli Alberto , Muller Karl , Coppin Peter , Davy Robert , Russell Chris , Hirsch Annette L.
Published: July 2011

Accurate estimates of long-term linear trends of wind speed provide a useful indicator for circulation changes in the atmosphere and are invaluable for the planning and financing of sectors such as wind energy. Here a large number of wind observations over Australia and reanalysis products are analyzed to compute such trends. After a thorough quality control of the observations, it is found that the wind speed trends for 1975–2006 and 1989–2006 over Australia are sensitive to the height of the station: they are largely negative for the 2-m data but are predominantly positive for the 10-m data. The mean relative trend at 2 m is −0.10 ± 0.03% yr−1 (−0.36 ± 0.04% yr−1) for the 1975–2006 (1989–2006) period, whereas at 10 m it is 0.90 ± 0.03% yr−1 (0.69 ± 0.04% yr−1) for the 1975–2006 (1989–2006) period. Also, at 10 m light winds tend to increase more rapidly than the mean winds, whereas strong winds increase less rapidly than the mean winds; at 2 m the trends in both light and strong winds vary in line with the mean winds. It was found that a qualitative link could be established between the observed features in the linear trends and some atmospheric circulation indicators (mean sea level pressure, wind speed at 850 hPa, and geopotential at 850 hPa), particularly for the 10-m observations. Further, the magnitude of the trend is also sensitive to the period selected, being closer to zero when a very long period, 1948–2006, is considered. As a consequence, changes in the atmospheric circulation on climatic time scales appear unlikely.
Hadley Cell Dynamics in a Virtually Dry Snowball Earth Atmosphere
Authors: Voigt Aiko , Held Isaac M. , Marotzke Jochem
Published: July 2011

The Hadley cell of a virtually dry snowball Earth atmosphere under equinox insolation is studied in a comprehensive atmospheric general circulation model. In contrast to the Hadley cell of modern Earth, momentum transport by dry convection, which is modeled as vertical diffusion of momentum, is important in the upper branch of the snowball Earth Hadley cell. In the zonal momentum balance, mean meridional advection of mean absolute vorticity is not only balanced by eddies but also by vertical diffusion of zonal momentum. Vertical diffusion also contributes to the meridional momentum balance by decelerating the Hadley cell through downgradient mixing of meridional momentum between its upper and lower branches. When vertical diffusion of momentum is suppressed in the upper branch, the Hadley cell strengthens by a factor of about 2. This is in line with the effect of vertical diffusion in the meridional momentum balance but in contrast with its effect in the zonal momentum balance. Neither axisymmetric Hadley cell theories based on angular momentum conservation nor eddy-permitting Hadley cell theories that neglect vertical diffusion of momentum are applicable to the snowball Earth Hadley cell. Because the snowball Earth Hadley cell is a particular realization of a dry Hadley cell, these results show that an appropriate description of dry Hadley cells should take into account vertical transport of momentum by dry convection.
A Time-Scale Decomposition Approach to Statistically Downscale Summer Rainfall over North China
Authors: Guo Yan , Li Jianping , Li Yun
Published: July 2011

A time-scale decomposition (TSD) approach to statistically downscale summer rainfall over North China is described. It makes use of two distinct downscaling models respectively corresponding to the interannual and interdecadal rainfall variability. The two models were developed based on objective downscaling scheme that 1) identifies potential predictors based on correlation analysis between rainfall and considered climatic variables over the global scale and 2) selects the “optimal” predictors from the identified potential predictors via cross-validation-based stepwise regression. The downscaling model for the interannual rainfall variability is linked to El Niño–Southern Oscillation and the 850-hPa meridional wind over East China, while the one for the interdecadal rainfall variability is related to the sea level pressure over the southwest Indian Ocean. Taking the downscaled interannual and interdecadal components together the downscaled total rainfall was obtained. The results show that the TSD approach achieved a good skill to predict the observed rainfall with the correlation coefficient of 0.82 in the independent validation period. The authors further apply the model to obtain downscaled rainfall projections from three climate models under present climate and the A1B emission scenario in future. The resulting downscaled values provide a closer representation of the observation than the raw climate model simulations in the present climate; for the near future, climate models simulated a slight decrease in rainfall, while the downscaled values tend to be slightly higher than the present state.
A Numerical Sensitivity Study of the Influence of Siberian Snow on the Northern Annular Mode
Authors: Peings Y. , Saint-Martin D. , Douville H.
Published: July 2011

The climate version of the general circulation model Action de Recherche Petite Echelle Grande Echelle (ARPEGE-Climat) is used to explore the relationship between the autumn Siberian snow and the subsequent winter northern annular mode by imposing snow anomalies over Siberia. As the model presents some biases in the representation of the polar vortex, a nudging methodology is used to obtain a more realistic but still interactive extratropical stratosphere in the model. Free and nudged sensitivity experiments are compared to discuss the dependence of the results on the northern stratosphere climatology. For each experiment, a positive snow mass anomaly imposed from October to March over Siberia leads to significant impacts on the winter atmospheric circulation in the extratropics. In line with previous studies, the model response resembles the negative phase of the Arctic Oscillation. The well-documented stratospheric pathway between snow and the Arctic Oscillation operates in the nudged experiment, while a more zonal propagation of the signal is found in the free experiment. Thus, the study provides two main findings: it supports the influence of Siberian snow on the winter extratropical circulation and highlights the importance of the northern stratosphere representation in the models to capture this teleconnection. These findings could have important implications for seasonal forecasting, as most of the operational models present biases similar to those of the ARPEGE-Climat model.
Projected Changes to Streamflow Characteristics over Western Canada as Simulated by the Canadian RCM
Authors: Poitras V. , Sushama L. , Seglenieks F. , Khaliq M. N. , Soulis E.
Published: July 2011

Intensification of the global hydrological cycle and increase in precipitation for some regions around the world, including the northern mid- to high latitudes, is expected in a changing climate. Changes in the amount of seasonal precipitation and the intensity and frequency of extreme precipitation events directly affect the magnitude of seasonal streamflows and the timing and severity of floods and droughts. In this study, the Canadian Regional Climate Model (CRCM) projected changes to streamflow characteristics (i.e., hydrologic regime, mean annual streamflows, and the timing, frequency, and magnitude of extreme flows—low and high) over selected basins in western Canada and assessment of errors associated with these characteristics in the current climate are presented. An ensemble of five current (1961–90) and five future (2041–70) simulations, corresponding to the Special Report on Emissions Scenarios (SRES) A2 scenario, are used in the assessment of projected changes; the ensemble of simulations allows better quantification of uncertainty in projected changes. Results of the study suggest an increase in the magnitude of winter streamflows and an earlier snowmelt peak for the northern basins. In addition, study of selected return levels of extreme flows suggest important changes to the timing, frequency, and magnitude of both low and high flows, with significant increases in 10-yr 15-day winter and fall low flows and 1-day high flows, for all the high-latitude west Canadian basins. The level of confidence in projected changes to mean annual streamflows is relatively higher compared to that for extreme flows for most of the basins studied.
On the Nature and Variability of the East Greenland Spill Jet: A Case Study in Summer 2003*
Authors: Magaldi M. G. , Haine T. W. N. , Pickart R. S.
Published: July 2011

Results from a high-resolution (~2 km) numerical simulation of the Irminger Basin during summer 2003 are presented. The focus is on the East Greenland Spill Jet, a recently discovered component of the circulation in the basin. The simulation compares well with observations of surface fields, the Denmark Strait overflow (DSO), and the hydrographic structure of typical sections in the basin. The model reveals new aspects of the circulation on scales of O(0.1–10) days and O(1–100) km.

The model Spill Jet results from the cascade of dense waters over the East Greenland shelf. Spilling can occur in various locations southwest of the strait, and it is present throughout the simulation but exhibits large variations on periods of O(0.1–10) days. The Spill Jet sometimes cannot be distinguished in the velocity field from surface eddies or from the DSO. The vorticity structure of the jet confirms its unstable nature with peak relative and tilting vorticity terms reaching twice the planetary vorticity term.

The average model Spill Jet transport is 4.9 ±1.7 Sv (1 Sv ≡ 106 m3 s−1) equatorward, about 2½ times larger than has been previously reported from a single ship transect in August 2001. Kinematic analysis of the model results suggests two different types of spilling events. In the first case (type I), a local perturbation results in dense waters descending over the shelf break into the Irminger Basin. In the second case (type II), surface cyclones associated with DSO deep domes initiate the spilling process. During summer 2003, more than half of the largest Spill Jet transport values are of type II.
Sea Surface Temperature Response to Tropical Cyclones
Authors: Dare Richard A. , McBride John L.
Published: July 2011

The response of sea surface temperature (SST) to tropical cyclones is studied using gridded SST data and global cyclone tracks from the period 1981–2008. A compositing approach is used whereby temperature time series before and after cyclone occurrence at individual cyclone track positions are averaged together.

Results reveal a variability of several days in the time of maximum cooling with respect to cyclone passage, with the most common occurrence 1 day after cyclone passage. When compositing is carried out relative to the day of maximum cooling, the global average response to cyclone passage is a local minimum SST anomaly of −0.9°C. The recovery of the ocean to cyclone passage is generally quite rapid with 44% of the data points recovering to climatological SST within 5 days, and 88% of the data points recovering within 30 days. Although differences exist between the mean results from the separate tropical cyclone basins, they are in broad agreement with the global mean results. Storm intensity and translation speed affect both the size of the SST response and the recovery time.

Cyclones occurring in the first half of the cyclone season disrupt the seasonal warming trend, which is not resumed until 20–30 days after cyclone passage. Conversely, cyclone occurrences in the later half of the season bring about a 0.5°C temperature drop from which the ocean does not recover due to the seasonal cooling cycle.
Green Shopping
Authors: Thøgersen John
Published: July 2011

Findings suggesting that consumers buy “green” products, such as organic foods, for selfish reasons are usually accepted at face value. In this article, the author argues that the evidence backing this claim is questionable and that it reflects post hoc rationalizations and self-presentation biases on behalf of respondents. Knowing that one has incurred substantial personal costs by contributing to a worthy cause can create an uneasiness that one is motivated to relieve, especially when one is uncertain about the ultimate impact of this contribution. A possible coping strategy is to adjust one’s beliefs about intangible private benefits in a way that justifies (bolsters) one’s purchasing decision. A survey study among a representative sample of approximately 4,000 respondents from four European countries (Denmark, Germany, United Kingdom, and Italy) confirmed that this is exactly what “green” consumers do. On the basis of Schwartz’s comprehensive Picture Value Questionnaire, it is also found that buying organic food is strongly, consistently, and positively related to unselfish values (i.e., universalism) but not selfish values (e.g., status, security, pleasure). This suggests that consumers at least start to buy these products for unselfish reasons (the common good). However, after having done so, they seem to bolster their beliefs about private benefits to preserve a self-image of being a competent and rational person.
Configurations of Instructional Leadership Enactments That Promote the Teaching and Learning of Mathematics in a New Zealand Elementary School
Authors: Higgins Joanna , Bonne Linda
Published: July 2011

Purpose: This article examines how and why four leadership functions are enacted in an elementary school, with a focus on hierarchical and “heterarchical” configurations of leadership. Research Design: The data were collected using an exploratory 2-year case study approach, and the data set comprises one-on-one interviews and relevant school documentation from school leaders and numeracy lead teachers engaged in reforming their mathematics teaching at an urban elementary school in a large New Zealand city. Four interrelated core functions of leadership are combined with configurations of leadership enactments to guide the analysis. Findings: The interplay between hierarchical and heterarchical enactments of leadership functions in hybrid forms appeared to strengthen the school’s work toward embedding the reform. Results indicate that the lead teacher can effectively support reform goals when this role is shared with others and when one lead teacher also holds a designated leadership role in the school, such as that of assistant principal. A list of strategies that supported embedding a reform in this school was developed from the findings. Conclusions: Combining leadership functions and configurations into one analytical frame is useful in building an understanding of the complexities of school-based leadership by capturing leadership enactments across all members of a school staff, not just those in designated leadership positions. What appears to be important in promoting instructional improvement is hybrid patterns of leadership—the combination of hierarchical and heterarchical leadership enactments—rather than either of these on their own.
Revisiting the Motivated Strategies for Learning Questionnaire
Authors: Dunn Karee E. , Lo Wen-Juo , Mulvenon Sean W. , Sutcliffe Rachel
Published: July 2011

The Motivated Strategies for Learning Questionnaire (MSLQ) has dominated self-regulated learning research since the early 1990s. In this study, the two MSLQ subscales specifically designed to assess self-regulation—Metacognitive Self-Regulation subscale and Effort Regulation subscale—were examined. Results indicated that the structure of the two scales is not supported by the original data reported by Pintrich, Smith, Garcia, and McKeachie in 1991 or new data. Statistical and theoretical analyses supported two modified scales, the General Strategies for Learning scale and the Clarification Strategies for Learning scale, that assess academic self-regulation from the original MSLQ items. The statistical and theoretical analyses, results, and modified scales are discussed.
QRAC-the-Code
Authors: Berkeley Sheri , Riccomini Paul J.
Published: July 2011

Requirements for reading and ascertaining information from text increase as students advance through the educational system, especially in content-rich classes; hence, monitoring comprehension is especially important. However, this is a particularly challenging skill for many students who struggle with reading comprehension, including students with learning disabilities. A randomized pre–post experimental design was employed to investigate the effectiveness of a comprehension monitoring strategy (QRAC-the-Code) for improving the reading comprehension of 323 students in Grades 6 and 7 in inclusive social studies classes. Findings indicated that both general education students and students with learning disabilities who were taught a simple comprehension monitoring strategy improved their comprehension of textbook content compared to students who read independently and noted important points. In addition, students in the comprehension monitoring condition reported using more reading strategies after the intervention. Implications for research and practice are discussed.
Regenerated cellulose fibers from waste bagasse using ionic liquid
Authors: Jiang Wei , Sun Liangfeng , Hao Ayou , Yan Chen Jonathan
Published: July 2011

Regenerated cellulose fibers from bagasse and wood were produced under various processing conditions using the ionic liquid 1-butyl-3-methylimidazolium chloride (BMIMCl) as a solvent. Two different ionic liquid solutions were prepared with 6 wt% of bagasse cellulose and 6 wt% of wood cellulose. The solutions were extruded with a dry-jet and wet-spinning method using water as a coagulation bath. A thermogravimetric analyzer (TGA) was used to measure the thermal properties of these regenerated fibers. Dynamic mechanical analysis (DMA) was used to determine the thermal mechanical property of the regenerated cellulose fibers and wide-angle X-ray diffraction (WAXD) was used to measure the degree of crystallinity, as well as the degree of crystal orientation for those experimental fibers. To evaluate the quantity of ionic liquid residue in the regenerated fibers, the instrumental methods of FT-IR and mass spectrometry were applied to test the residues of BMIMCl in the regenerated fibers. Research results indicated increases in the degree of crystallinity and storage modulus under a higher fiber drawing speed. Both regenerated bagasse film and regenerated wood film had similar thermal properties. However, the regenerated bagasse fibers showed a higher degree of crystallinity, and higher tenacity than the regenerated wood fibers obtained under the same condition. The study also revealed that water treatment would be helpful for eliminating the ionic liquid residue in the regenerated fibers.
The Four Personae of Racism
Authors: Young Evelyn Y.
Published: July 2011

This study used CRT to engage educators in critical discourse regarding the persistence of racism in urban schooling. A combined method of action research and critical case study was employed to raise a group of educators’ race consciousness through antiracist training. Findings revealed conflicting views of racism as an individual pathology vs. a systemic problem, which led to the development of four personae of racism: the conscious perpetrators, the unconscious perpetrators, the deceived perpetrators/activists, and the enlightened perpetrators/activists. The study found that the participants were largely deceived by their social activism to recognize their perpetuation of racism through their practice.
Ethnic Matching, School Placement, and Mathematics Achievement of African American Students From Kindergarten Through Fifth Grade
Authors: Eddy Colleen M. , Easton-Brooks Donald
Published: July 2011

Educators, administrators, and policymakers focus much attention on closing the achievement gap, and various approaches have been suggested. The present study focuses on one approach being suggested: student–teacher ethnic matching. The study focused on the long-term contributions of African American ethnic matching to mathematical test scores of 1,200 African American students from the Early Childhood Longitudinal Kindergarten—fifth data set. Employing a two-level growth model, this study of impact from student–teacher ethnic matching revealed that a student having at least one teacher who ethnically matched themselves between kindergarten and fifth grade had a significant impact on mathematics achievement.
Behavioral Norms, Moral Judgments, and Social Approval of Participant Roles in School Bullying in a Singapore Sample
Authors: Sim Tick Ngee , Tan Melinda Meizhen
Published: July 2011

This study examines behavioral norms, moral judgments, and social approval of participant roles in classroom physical, verbal, and relational bullying, including a relatively new reporter role (where nothing is done during the bullying but there is subsequent reporting to a teacher). A sample of 1,131 Secondary 1 (mean age = 12 years 7 months) and Secondary 3 (mean age = 14 years 8 months) students in Singapore are given hypothetical situations and norms, judgments, and approval of the participant roles sought. Roles are found to differ in norms, judgments, and approval, with the reporter role judged as rather likely but less likely judged as right or with approval compared to other roles. In addition, participant role and secondary level interact for norms, judgments, and approval. Participant role also interacts with gender for judgments and approval and with bullying type for norms and approval. The reporter role is thus one worth further investigation.
The Motivation of Public Sector Employees
Authors: Matheson Craig
Published: July 2011

This article argues that psychological factors determine the content of people’s work motivations but that social factors determine their relative importance. The author identified six universal human needs and corresponding rewards, orientations to work, organizational control methods, and types of involvement. The author used data from a public sector organization to illustrate these orientations. He used Randall Collins’s ritual interaction theory and Etzioni’s compliance theory to explain why ritual, utilitarian, and intrinsic rewards yield moral, calculative, and intrinsic forms of involvement. He concludes that motivation varies more in accordance with hierarchical rank, control methods, and occupation than it does with sectoral location.
I Want to Quit
Authors: Caillier James Gerard
Published: July 2011

In the article, a model was developed to examine turnover intentions and was subsequently tested on state government employees. The findings from this model robustly indicated that quit intentions were lower among satisfied and high-performing employees. Contrary to what was expected, the results also demonstrated that public service motivation was positively associated with employee turnover intentions. On the other hand, participation in decision making, mission-contribution, and a fair reward system were not associated with employee leave intentions. The implications of these findings are thoroughly discussed in the article.