bluuebunny/crossref_metadata_2025 huggingface dataset:
Knowledge and Self-Reported Practice of Universal Precautions among Kuwait University Medical Students in Their Clinical Years
Authors: Karim Jumanah , Al-Saraji Mariam , Al-Mousawi Fatma , Al-Haddad Zahra , Al-Sharaf Dina , Marwan Yousef , Akhtar Saeed
Published: January 2012

Objectives: This cross-sectional study aimed to assess the knowledge and practice of universal precautions among Faculty of Medicine, Kuwait University, medical students in their clinical years. Subjects and Methods: A self-administered questionnaire including 9 knowledge and 9 practice questions of universal precautions was used. A score was calculated for both knowledge and practice. These scores were dichotomized into less than median score (poor) and more than median score (good). 244 students were invited to participate. Results: Of the 244 students, 220 (90.2%) accepted to participate. Of the 9 knowledge questions about universal precautions, 7 were answered correctly by more than 60% (range 64.8–90.4) of the students. All questions regarding the practice of universal precautions were answered correctly by over 60% (range 61.8–96.4) of the students. The prevalence of poor knowledge was 38.2% (84/220) and poor practice was 27.7% (61/220). Grade point average was significantly (p = 0.008) associated with the knowledge status of the respondents; however, it was not significantly associated (p = 0.397) with practice of universal precautions. Furthermore, neither the knowledge status nor any of the sociodemographic variables were significantly associated with the practice of universal precautions. Conclusions: A substantial number of students of the Faculty of Medicine, Kuwait University, in their clinical years appeared to have poor level of both knowledge and practice of universal precautions. Efforts are needed to optimize the level of knowledge and practice among students to minimize the risk of preventable infections.
Protocol for Measurement of Mean Arterial Pressure at 11-13 Weeks' Gestation
Authors: Poon L.C.Y. , Zymeri N.A. , Zamprakou A. , Syngelaki A. , Nicolaides K.H.
Published: January 2012

Objectives: To identify the best protocol for measurement of mean arterial pressure (MAP) in early pregnancy for the prediction of preeclampsia (PE). Methods: This was a prospective study in singleton pregnancies attending for a routine hospital visit at 11-13 weeks' gestation when a minimum of four recordings of MAP were taken from each arm. The performance of screening for PE by different combinations of MAP was compared to the protocol of the National Heart Foundation of Australia (NHFA). Results: The MAP was measured in 587 (2.4%) cases that developed PE and in 22,900 that were unaffected by hypertensive disorders in pregnancy. The area under the receiver operating characteristic curve (AUROC) for prediction of PE by MAP as recommended by the NHFA protocol was 0.773 (95% CI 0.768-0.778). This AUROC was not significantly different from the AUROC obtained by the average MAP of the first three measurements from one arm (0.765, 95% CI 0.760-0.771) or the average of the first (0.766, 95% CI 0.760-0.771), the first two (0.771, 95% CI 0.766-0.777), or the first three measurements from the two arms (0.773, 95% CI 0.768-0.778). Conclusion: Performance of screening for PE by taking the average of a minimum of two measurements from both arms is comparable to the NHFA protocol.
Prevalence of ANGPTL3 and APOB Gene Mutations in Subjects With Combined Hypolipidemia
Authors: Noto Davide , Cefalù Angelo B. , Valenti Vincenza , Fayer Francesca , Pinotti Elisa , Ditta Mariangela , Spina Rossella , Vigna Giovanni , Yue Pin , Kathiresan Sekar , Tarugi Patrizia , Averna Maurizio R.
Published: January 2012

Objective—

Mutations of the
ANGPTL3
gene have been associated with a novel form of primary hypobetalipoproteinemia, the combined hypolipidemia (cHLP), characterized by low total cholesterol and low HDL-cholesterol levels. The aim of this work is to define the role of
ANGPTL3
gene as determinant of the combined hypolipidemia phenotype in 2 large cohorts of 913 among American and Italian subjects with primary hypobetalipoproteinemia (total cholesterol <5th percentile).

Methods and Results—

The combined hypolipidemia cut-offs were chosen according to total cholesterol and HDL-cholesterol levels reported in the ANGPTL3 kindred described to date: total cholesterol levels, <2nd percentile and HDL-cholesterol, levels <2nd decile. Seventy-eight subjects with combined hypolipidemia were analyzed for
ANGPTL3
and
APOB
genes. We identified nonsense and/or missense mutations in
ANGPTL3
gene in 8 subjects; no mutations of the
APOB
gene were found. Mutated
ANGPTL3
homozygous/compound heterozygous subjects showed a more severe biochemical phenotype compared to heterozygous or
ANGPTL3
negative subjects, although
ANGPTL3
heterozygotes did not differ from
ANGPTL3
negative subjects.

Conclusion—

These results demonstrated that in a cohort of subjects with severe primary hypobetalipoproteinemia the prevalence of
ANGPTL3
gene mutations responsible for a combined hypolipidemia phenotype is about 10%, whereas mutations of
APOB
gene are absent.
Pro-Inflammatory Role of MicroRNA-200 in Vascular Smooth Muscle Cells From Diabetic Mice
Authors: Reddy Marpadga A. , Jin Wen , Villeneuve Louisa , Wang Mei , Lanting Linda , Todorov Ivan , Kato Mitsuo , Natarajan Rama
Published: January 2012

Objective—

Vascular smooth muscle cells (VSMC) from type 2 diabetic db/db mice exhibit enhanced proinflammatory responses implicated in accelerated vascular complications. We examined the role of microRNA(miR)-200 family members and their target Zeb1, an E-box binding transcriptional repressor, in these events.

Methods and Results—

The expression levels of miR-200b, miR-200c, and miR-429 were increased, although protein levels of Zeb1 were decreased in VSMC and aortas from db/db mice relative to control db/+ mice. Transfection of miR-200 mimics into VSMC downregulated Zeb1 by targeting its 3′-UTR, upregulated the inflammatory genes cyclooxygenase-2 and monocyte chemoattractant protein-1, and promoted monocyte binding in db/+VSMC. In contrast, miR-200 inhibitors reversed the enhanced monocyte binding of db/dbVSMC. Zeb1 gene silencing with siRNAs also increased these proinflammatory responses in db/+VSMC confirming negative regulatory role of Zeb1. Both miR-200 mimics and Zeb1 siRNAs increased cyclooxygenase-2 promoter transcriptional activity. Chromatin immunoprecipitation showed that Zeb1 occupancy at inflammatory gene promoters was reduced in VSMC from type 2 diabetic db/db mice. Furthermore, Zeb1 knockdown increased miR-200 levels demonstrating a feedback regulatory loop.

Conclusion—

Disruption of the reciprocal negative regulatory loop between miR-200 and Zeb1 under diabetic conditions enhances proinflammatory responses of VSMC implicated in vascular complications.
Dynamic Immune Cell Accumulation During Flow-Induced Atherogenesis in Mouse Carotid Artery
Authors: Alberts-Grill Noah , Rezvan Amir , Son Dong Ju , Qiu Haiwei , Kim Chan Woo , Kemp Melissa L. , Weyand Cornelia M. , Jo Hanjoong
Published: January 2012

Objective—

Inflammation plays a central role in atherosclerosis. However, the detailed changes in the composition and quantity of leukocytes in the arterial wall during atherogenesis are not fully understood in part because of the lack of suitable methods and animal models.

Methods and Results—

We developed a 10-fluorochrome, 13-parameter flow cytometry method to quantitate 7 major leukocyte subsets in a single digested arterial wall sample. Apolipoprotein E–deficient mice underwent left carotid artery (LCA) partial ligation and were fed a high-fat diet for 4 to 28 days. Monocyte/macrophages, dendritic cells, granulocytes, natural killer cells, and CD4 T cells significantly infiltrated the LCA as early as 4 days. Monocyte/macrophages and dendritic cells decreased between 7 and 14 days, whereas T-cell numbers remained steady. Leukocyte numbers peaked at 7 days, preceding atheroma formation at 14 days. B cells entered LCA by 14 days. Control right carotid and sham-ligated LCAs showed no significant infiltrates. Polymerase chain reaction and ELISA arrays showed that expression of proinflammatory cytokines and chemokines peaked at 7 and 14 days postligation, respectively.

Conclusion—

This is the first quantitative description of leukocyte number and composition over the life span of murine atherosclerosis. These results show that disturbed flow induces rapid and dynamic leukocyte accumulation in the arterial wall during the initiation and progression of atherosclerosis.
CD36 Ectodomain Phosphorylation Blocks Thrombospondin-1 Binding
Authors: Chu Ling-Yun , Silverstein Roy L.
Published: January 2012

Objective—

CD36 phosphorylation on its extracellular domain inhibits binding of thrombospondin-1. The mechanisms of cellular CD36 ectodomain phosphorylation and whether it can be regulated in cells are not known. We determined structure-function relationships of CD36 phosphorylation related to thrombospondin-1 peptide binding in vitro and explored mechanisms regulating phosphorylation by protein kinase C (PKC) in melanoma cells.

Methods and Results—

Phosphorylation of CD36 peptide on Thr92 by PKCα suppressed binding of thrombospondin-1 peptides in vitro, and the level of inhibition correlated with the level of phosphorylation. Basal phosphorylation levels of CD36 in vivo in platelets, endothelial cells, and melanoma cells were assessed by immunoprecipitation and immunoblot and were found to be very low. Treatment of CD36-transfected melanoma cells with phorbol 12-myristate 13-acetate (PMA), a PKC activator, induced substantial CD36 phosphorylation and decreased ligand-mediated recruitment of Src-family proteins to CD36. PMA treatment did not induce detectable extracellular or cell surface–associated kinase activity, and both cycloheximide and brefeldin A blocked CD36 phosphorylation.

Conclusion—

New protein synthesis and trafficking through the Golgi are required for PMA-induced CD36 phosphorylation, suggesting that phosphorylation probably occurs intracellularly. These studies suggest a novel in vivo pathway for CD36 phosphorylation that modulates cellular affinity for thrombospondin-related proteins to blunt vascular cell signaling.
EphA2 Activation Promotes the Endothelial Cell Inflammatory Response
Authors: Funk Steven Daniel , Yurdagul Arif , Albert Patrick , Traylor James G. , Jin Long , Chen Jin , Orr A. Wayne
Published: January 2012

Objective—

Endothelial cell activation results in altered cell-cell interactions with adjacent endothelial cells and with infiltrating leukocytes. Eph receptors and their ephrin ligands regulate cell-cell interactions during tissue remodeling, and multiple proinflammatory mediators induce endothelial EphA receptor and ephrinA ligand expression. Therefore, we sought to elucidate the role of EphA receptors and ephrinA ligands in endothelial cell activation and atherosclerosis.

Methods and Results—

Quantitative reverse transcription–polymerase chain reaction screening for EphA/ephrinA expression in atherosclerosis-prone macrovascular endothelium identified EphA2, EphA4, and ephrinA1 as the dominant isoforms. Endothelial activation with oxidized low-density lipoprotein and proinflammatory cytokines induced EphA2 and ephrinA1 expression and sustained EphA2 activation, whereas EphA4 expression was unaffected. Atherosclerotic plaques from mice and humans showed enhanced EphA2 and ephrinA1 expression colocalizing in the endothelial cell layer. EphA2 activation with recombinant Fc-ephrinA1 induced proinflammatory gene expression (eg vascular cell adhesion molecule-1, E-selectin) and stimulated monocyte adhesion, whereas inhibiting EphA2 (small interfering RNA, pharmacological inhibitors) abrogated both ephrinA1-induced and oxidized low-density lipoprotein–induced vascular cell adhesion molecule-1 expression.

Conclusion—

The current data suggest that enhanced EphA2 signaling during endothelial cell activation perpetuates proinflammatory gene expression. Coupled with EphA2 expression in mouse and human atherosclerotic plaques, these data implicate EphA2 as a novel proinflammatory mediator and potential regulator of atherosclerotic plaque development.
Bmp Signaling Exerts Opposite Effects on Cardiac Differentiation
Authors: de Pater Emma , Ciampricotti Metamia , Priller Florian , Veerkamp Justus , Strate Ina , Smith Kelly , Lagendijk Anne Karine , Schilling Thomas F. , Herzog Wiebke , Abdelilah-Seyfried Salim , Hammerschmidt Matthias , Bakkers Jeroen
Published: January 2012

Rationale:

The importance for Bmp signaling during embryonic stem cell differentiation into myocardial cells has been recognized. The question when and where Bmp signaling in vivo regulates myocardial differentiation has remained largely unanswered.

Objective:

To identify when and where Bmp signaling regulates cardiogenic differentiation.

Methods and Results:

Here we have observed that in zebrafish embryos, Bmp signaling is active in cardiac progenitor cells prior to their differentiation into cardiomyocytes. Bmp signaling is continuously required during somitogenesis within the anterior lateral plate mesoderm to induce myocardial differentiation. Surprisingly, Bmp signaling is actively repressed in differentiating myocardial cells. We identified the inhibitory Smad6a, which is expressed in the cardiac tissue, to be required to inhibit Bmp signaling and thereby promote expansion of the ventricular myocardium.

Conclusion:

Bmp signaling exerts opposing effects on myocardial differentiation in the embryo by promoting as well as inhibiting cardiac growth.
White Matter Protection in Congenital Heart Surgery
Authors: Ishibashi Nobuyuki , Scafidi Joseph , Murata Akira , Korotcova Ludmila , Zurakowski David , Gallo Vittorio , Jonas Richard A.
Published: January 2012

Background—

Neurodevelopmental delays in motor skills and white matter (WM) injury have been documented in congenital heart disease and after pediatric cardiac surgery. The lack of a suitable animal model has hampered our understanding of the cellular mechanisms underlying WM injury in these patients. Our aim is to identify an optimal surgical strategy for WM protection to reduce neurological injury in congenital heart disease patients.

Methods and Results—

We developed a porcine cardiopulmonary bypass model that displays area-dependent WM maturation. In this model, WM injury was identified after cardiopulmonary bypass–induced ischemia-reperfusion injury. The degree of injury was inversely correlated with the maturation stage, which indicates maturation-dependent vulnerability of WM. Within different oligodendrocyte developmental stages, we show selective vulnerability of O4
+
preoligodendrocytes, whereas oligodendrocyte progenitor cells were resistant to insults. This indicates that immature WM is vulnerable to cardiopulmonary bypass–induced injury but has an intrinsic potential for recovery mediated by endogenous oligodendrocyte progenitor cells. Oligodendrocyte progenitor cell number decreased with age, which suggests that earlier repair allows successful WM development. Oligodendrocyte progenitor cell proliferation was observed within a few days after cardiopulmonary bypass–induced ischemia-reperfusion injury; however, by 4 weeks, arrested oligodendrocyte maturation and delayed myelination were detected. Logistic model confirmed that maintenance of higher oxygenation and reduction of inflammation were effective in minimizing the risk of injury at immature stages of WM development.

Conclusions—

Primary repair in neonates and young infants potentially provides successful WM development in congenital heart disease patients. Cardiac surgery during this susceptible period should avoid ischemia-reperfusion injury and minimize inflammation to prevent long-term WM-related neurological impairment.
Factors Associated With Prehospital Delays in the Presentation of Acute Stroke in Urban China
Authors: Jin Haiqiang , Zhu Sainan , Wei Jade W. , Wang Jiguang , Liu Ming , Wu Yangfeng , Wong Lawrence K.S. , Cheng Yan , Xu En , Yang Qidong , Anderson Craig S. , Huang Yining ,   for the ChinaQUEST (Quality Evaluation of Stroke Care and Treatment) Investigators
Published: January 2012

Background and Purpose—

Low rates of thrombolysis for ischemic stroke in China have mainly been attributed to delays in presentation to the hospital. This study aimed to evaluate factors associated with these delays.

Methods—

Data were from a prospective, multicenter, hospital-based registry of patients with acute stroke (ChinaQUEST [Quality Evaluation of Stroke Care and Treatment]), which involved 62 hospitals across a variety of economic and geographic regions in China during 2006. Univariate and multivariate analyses were undertaken to determine associations between variables of interest and delays to hospital presentation.

Results—

Median time to hospital presentation was 15.0 hours for 6102 cases (interquartile range, 2.8–51.0 hours). A total of 1546 (25%) patients arrived within 3 hours and 2244 (37%) patients arrived within 6 hours after symptom onset. Factors that prolonged time to presentation were: visiting a local doctor before presenting at emergency (OR, 0.48;
P
<0.001), symptom onset at home (OR, 0.62;
P
<0.001), transfer to a large (Level III) hospital for management (OR, 0.70;
P
=0.04), and history of diabetes (OR, 0.78;
P
=0.01). In contrast, factors that accelerated presentation to the hospital were hemorrhagic stroke (OR, 2.25;
P
<0.001), history of atrial fibrillation (OR, 1.94;
P
<0.001), unconsciousness at presentation (OR, 1.91;
P
<0.001), transfer by ambulance (OR, 1.91;
P
<0.001), and history of coronary artery disease (OR, 1.20;
P
=0.04).

Conclusions—

Health promotion strategies to improve community awareness of early symptoms of stroke, establishment of an alert system to cater for patients likely to experience stroke at home, and wider availability and use of ambulance services are promising methods to help expedite presentation to hospital poststroke and thereby improve the management of stroke in China.
Transition to Collateral Flow After Arterial Occlusion Predisposes to Cerebral Venous Steal
Authors: Pranevicius Osvaldas , Pranevicius Mindaugas , Pranevicius Henrikas , Liebeskind David S.
Published: January 2012

Background and Purpose—

Stroke-related tissue pressure increase in the core and penumbra determines regional cerebral perfusion pressure (rCPP) defined as a difference between local inflow pressure and venous or tissue pressure, whichever is higher. We previously showed that venous pressure reduction below the pressure in the core causes blood flow diversion–cerebral venous steal. Now we investigated how transition to collateral circulation after complete arterial occlusion affects rCPP distribution.

Methods—

We modified parallel Starling resistor model to simulate transition to collateral inflow after complete main stem occlusion. We decreased venous pressure from the arterial pressure to zero and investigated how arterial and venous pressure elevation augments rCPP.

Results—

When core pressure exceeded venous, rCPP=inflow pressure in the core. Venous pressure decrease from arterial pressure to pressure in the core caused smaller inflow pressure to drop augmenting rCPP. Further drop of venous pressure decreased rCPP in the core but augmented rCPP in penumbra. After transition to collateral circulation, lowering venous pressure below pressure in the penumbra further decreased rCPP and collaterals themselves became a pathway for steal. Venous pressure level at which rCPP in the core becomes zero we termed the “point of no reflow.” Transition from direct to collateral circulation resulted in decreased inflow pressure, decreased rCPP, and a shift of point of no reflow to higher venous loading values. Arterial pressure augmentation increased rCPP, but only after venous pressure exceeded point of no reflow.

Conclusions—

In the presence of tissue pressure gradients, transition to collateral flow predisposes to venous steal (collateral failure), which may be reversed by venous pressure augmentation.
Critique of “Stenting Versus Aggressive Medical Therapy for Intracranial Arterial Stenosis” by Chimowitz et al in the
New England Journal of Medicine
Authors: Abou-Chebl Alex , Steinmetz Helmuth
Published: January 2012

Symptomatic intracranial stenoses are an important cause of stroke and have a high risk of recurrent stroke with medical therapy. The Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Arterial Stenosis (SAMMPRIS) trial unexpectedly showed a higher-than-expected rate of complications with intracranial stenting and a lower-than-expected recurrence rate with medical therapy. In this commentary, the authors review possible explanations for these findings and suggest future strategies for study.
Is There a Future for Endovascular Treatment of Intracranial Atherosclerotic Disease After Stenting and Aggressive Medical Management for Preventing Recurrent Stroke and Intracranial Stenosis (SAMMPRIS)?
Authors: Marks Michael P.
Published: January 2012

The Stenting and Aggressive Medical Management for Preventing Recurrent Stroke and Intracranial Stenosis (SAMMPRIS) trial, a randomized clinical trial comparing aggressive medical management to stenting with aggressive medical management for symptomatic intracranial stenosis, was prematurely halted when a high rate of periprocedural events was found in the stent arm. The trial also demonstrated a high rate of stroke with medical management. This article explores possible reasons for these outcomes and discusses some weaknesses of the trial. Against this background endovascular therapy should continue to be explored in the treatment of this disease.
Geographical Indications, Biodiversity and Traditional Knowledge: Obligations and Opportunities for the Kingdom of Saudi Arabia
Authors: Williamson Myra E.J.B.
Published: January 2012

Abstract

This article examines the Kingdom of Saudi Arabia’s legal obligations in one area of intellectual property law, namely, geographical indications (GI). It considers the opportunities for improving the existing legal framework from both a domestic and an international perspective. After an introduction, Section 2 presents a survey of the existing domestic and international laws pertaining to the protection of GIs. Section 3 outlines the relationship between GIs, biodiversity and traditional knowledge. Section 4 summarizes some of the latest developments and points of debate regarding increased protection of GIs. Finally, Section 5 puts forward several recommendations for improving the protection of GIs in the Kingdom of Saudi Arabia.
A Large-Eddy Simulation Study of Thermal Effects on Turbulent Flow and Dispersion in and above a Street Canyon
Authors: Park Seung-Bu , Baik Jong-Jin , Raasch Siegfried , Letzel Marcus Oliver
Published: January 2012

Thermal effects on turbulent flow and dispersion in and above an idealized street canyon with a street aspect ratio of 1 are numerically investigated using the parallelized large-eddy simulation model (“PALM”). Each of upwind building wall, street bottom, and downwind building wall is heated, and passive scalars are emitted from the street bottom. When compared with the neutral (no heating) case, the heating of the upwind building wall or street bottom strengthens a primary vortex in the street canyon and the heating of the downwind building wall induces a shrunken primary vortex and a winding flow between the vortex and the downwind building wall. Heating also induces higher turbulent kinetic energy and stronger turbulent fluxes at the rooftop height. In the neutral case, turbulent eddies generated by shear instability dominate mixing at the rooftop height and appear as band-shaped perturbations in the time–space plots of turbulent momentum and scalar fluxes. In all of the heating cases, buoyancy-generated turbulent eddies as well as shear-generated turbulent eddies contribute to turbulent momentum and scalar fluxes and band-shaped or lump-shaped perturbations appear at the rooftop height. A quadrant analysis shows that at the rooftop height, in the neutral case and in the case with upwind building-wall heating, sweep events are less frequent but contribute more to turbulent momentum flux than do ejection events. By contrast, in the case with street-bottom and downwind building-wall heating, the frequency of sweep events is similar to that of ejection events and the contribution of ejection events to turbulent momentum flux is comparable to that of sweep events.
Coordinated Abrupt Weakening of the Eurasian and North African Monsoons in the 1960s and Links to Extratropical North Atlantic Cooling
Authors: Liu Y. , Chiang J. C. H.
Published: January 2012

Previous modeling and paleoclimate studies have suggested that cooling originating from the extratropical North Atlantic can abruptly weaken the Eurasian and North African monsoons. The climatic signature includes a widespread cooling over the Eurasian and North African continents and an associated increase to surface pressure. It is explored whether such coordinated changes are similarly exhibited in the observed twentieth-century climate, in particular with the well-documented shift of Sahel rainfall during the 1960s. Surface temperature, sea level pressure, and precipitation changes are analyzed using combined principal component analysis (CPCA). The leading mode exhibits a monotonic shift in the 1960s, and the transition is associated with a relative cooling and pressure increase over the interior Eurasia and North Africa, and rainfall reduction over the Sahel, South Asia, and East Asia. The local circulation changes suggest that the rainfall shift results from the regional response of the summer monsoons to these continental-wide changes. A similar CPCA analysis of atmospheric general circulation model (AGCM) simulations forced by twentieth-century-observed forcings shows similar results, suggesting that origins of the climate shift reside in the sea surface temperature changes, specifically over the extratropical North Atlantic. Finally, an AGCM forced with extratropical North Atlantic cooling appears to simulate these climate impacts, at least qualitatively. The result herein shows that the observed climate signature of the 1960s abrupt shift in Eurasian and North African climate is consistent with the influence of the abrupt high-latitude North Atlantic cooling that occurred in the late 1960s. A definitive causal relationship remains to be shown, and mechanisms elucidated.
Skill, Correction, and Downscaling of GCM-Simulated Precipitation
Authors: Eden Jonathan M. , Widmann Martin , Grawe David , Rast Sebastian
Published: January 2012

The ability of general circulation models (GCMs) to correctly simulate precipitation is usually assessed by comparing simulated mean precipitation with observed climatologies. However, to what extent the skill in simulating average precipitation indicates how well the models represent temporal changes is unclear. A direct assessment of the latter is hampered by the fact that freely evolving climate simulations for past periods are not set up to reproduce the specific evolution of internal atmospheric variability. Therefore, model-to-real-world comparisons of time series of daily, monthly, or annual precipitation are not meaningful. Here, for the first time, the authors quantify GCM skill in simulating precipitation variability using simulations in which the temporal evolution of the large-scale atmospheric state closely matches that of the real world. This is achieved by nudging the atmospheric states in the ECHAM5 GCM, but crucially not the precipitation field itself, toward the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40). Global correlation maps between observed and simulated seasonal precipitation allow areas in which simulated future precipitation changes are likely to be meaningful to be identified. In many areas, correlations higher than 0.8 are found.

This means also that in these regions the simulated precipitation is a very good predictor for the true precipitation, and thus a statistical correction of the simulated precipitation, which can include a downscaling component, can provide useful estimates for local-scale precipitation. The authors show that a simple scaling of the simulated precipitation performs well in a cross validation and thus appears to be a promising alternative to standard statistical downscaling approaches.
Water Mass Analysis of Effect of Climate Change on Air–Sea CO2 Fluxes: The Southern Ocean
Authors: Séférian Roland , Iudicone Daniele , Bopp Laurent , Roy Tilla , Madec Gurvan
Published: January 2012

Impacts of climate change on air–sea CO2 exchange are strongly region dependent, particularly in the Southern Ocean. Yet, in the Southern Ocean the role of water masses in the uptake of anthropogenic carbon is still debated. Here, a methodology is applied that tracks the carbon flux of each Southern Ocean water mass in response to climate change. A global marine biogeochemical model was coupled to a climate model, making 140-yr Coupled Model Intercomparison Project phase 5 (CMIP5)-type simulations, where atmospheric CO2 increased by 1% yr−1 to 4 times the preindustrial concentration (4 × CO2). Impacts of atmospheric CO2 (carbon-induced sensitivity) and climate change (climate-induced sensitivity) on the water mass carbon fluxes have been isolated performing two sensitivity simulations. In the first simulation, the atmospheric CO2 influences solely the marine carbon cycle, while in the second simulation, it influences both the marine carbon cycle and earth’s climate. At 4 × CO2, the cumulative carbon uptake by the Southern Ocean reaches 278 PgC, 53% of which is taken up by modal and intermediate water masses. The carbon-induced and climate-induced sensitivities vary significantly between the water masses. The carbon-induced sensitivities enhance the carbon uptake of the water masses, particularly for the denser classes. But, enhancement strongly depends on the water mass structure. The climate-induced sensitivities either strengthen or weaken the carbon uptake and are influenced by local processes through changes in CO2 solubility and stratification, and by large-scale changes in outcrop surface (OS) areas. Changes in OS areas account for 45% of the climate-induced reduction in the Southern Ocean carbon uptake and are a key factor in understanding the future carbon uptake of the Southern Ocean.
Nonlinear Trends, Long-Range Dependence, and Climate Noise Properties of Surface Temperature
Authors: Franzke Christian
Published: January 2012

This study investigates the significance of trends of four temperature time series—Central England Temperature (CET), Stockholm, Faraday-Vernadsky, and Alert. First the robustness and accuracy of various trend detection methods are examined: ordinary least squares, robust and generalized linear model regression, Ensemble Empirical Mode Decomposition (EEMD), and wavelets. It is found in tests with surrogate data that these trend detection methods are robust for nonlinear trends, superposed autocorrelated fluctuations, and non-Gaussian fluctuations. An analysis of the four temperature time series reveals evidence of long-range dependence (LRD) and nonlinear warming trends. The significance of these trends is tested against climate noise. Three different methods are used to generate climate noise: (i) a short-range-dependent autoregressive process of first order [AR(1)], (ii) an LRD model, and (iii) phase scrambling. It is found that the ability to distinguish the observed warming trend from stochastic trends depends on the model representing the background climate variability. Strong evidence is found of a significant warming trend at Faraday-Vernadsky that cannot be explained by any of the three null models. The authors find moderate evidence of warming trends for the Stockholm and CET time series that are significant against AR(1) and phase scrambling but not the LRD model. This suggests that the degree of significance of climate trends depends on the null model used to represent intrinsic climate variability. This study highlights that in statistical trend tests, more than just one simple null model of intrinsic climate variability should be used. This allows one to better gauge the degree of confidence to have in the significance of trends.
Determining Robust Impacts of Land-Use-Induced Land Cover Changes on Surface Climate over North America and Eurasia: Results from the First Set of LUCID Experiments
Authors: de Noblet-Ducoudré Nathalie , Boisier Juan-Pablo , Pitman Andy , Bonan G. B. , Brovkin V. , Cruz Faye , Delire C. , Gayler V. , van den Hurk B. J. J. M. , Lawrence P. J. , van der Molen M. K. , Müller C. , Reick C. H. , Strengers B. J. , Voldoire A.
Published: January 2012

The project Land-Use and Climate, Identification of Robust Impacts (LUCID) was conceived to address the robustness of biogeophysical impacts of historical land use–land cover change (LULCC). LUCID used seven atmosphere–land models with a common experimental design to explore those impacts of LULCC that are robust and consistent across the climate models. The biogeophysical impacts of LULCC were also compared to the impact of elevated greenhouse gases and resulting changes in sea surface temperatures and sea ice extent (CO2SST). Focusing the analysis on Eurasia and North America, this study shows that for a number of variables LULCC has an impact of similar magnitude but of an opposite sign, to increased greenhouse gases and warmer oceans. However, the variability among the individual models’ response to LULCC is larger than that found from the increase in CO2SST. The results of the study show that although the dispersion among the models’ response to LULCC is large, there are a number of robust common features shared by all models: the amount of available energy used for turbulent fluxes is consistent between the models and the changes in response to LULCC depend almost linearly on the amount of trees removed. However, less encouraging is the conclusion that there is no consistency among the various models regarding how LULCC affects the partitioning of available energy between latent and sensible heat fluxes at a specific time. The results therefore highlight the urgent need to evaluate land surface models more thoroughly, particularly how they respond to a perturbation in addition to how they simulate an observed average state.
Effect of Atmospheric Feedbacks on the Stability of the Atlantic Meridional Overturning Circulation
Authors: Toom Matthijs den , Dijkstra Henk A. , Cimatoribus Andrea A. , Drijfhout Sybren S.
Published: January 2012

The impact of atmospheric feedbacks on the multiple equilibria (ME) regime of the Atlantic meridional overturning circulation (MOC) is investigated using a fully implicit hybrid coupled model (HCM). The HCM consists of a global ocean model coupled to an empirical atmosphere model that is based on linear regressions of the heat, net evaporative, and momentum fluxes generated by a fully coupled climate model onto local as well as Northern Hemisphere averaged sea surface temperatures. Using numerical continuation techniques, bifurcation diagrams are constructed for the HCM with the strength of an anomalous freshwater flux as the bifurcation parameter, which allows for an efficient first-order estimation of the effect of interactive surface fluxes on the MOC stability. The different components of the atmospheric fluxes are first considered individually and then combined. Heat feedbacks act to destabilize the present-day state of the MOC and to stabilize the collapsed state, thus leaving the size of the ME regime almost unaffected. In contrast, interactive freshwater fluxes cause a destabilization of both the present-day and collapsed states of the MOC. Wind feedbacks are found to have a minor impact. The joint effect of the three interactive fluxes is to narrow the range of ME. The shift of the saddle-node bifurcation that terminates the present-day state of the ocean is further investigated by adjoint sensitivity analysis of the overturning rate to surface fluxes. It is found that heat feedbacks primarily affect the MOC stability when they change the heat fluxes over the North Atlantic subpolar gyre, whereas interactive freshwater fluxes have an effect everywhere in the Atlantic basin.
On Estimating Wet Canopy Evaporation from Deciduous and Coniferous Forests in the Asian Monsoon Climate
Authors: Kang Minseok , Kwon Hyojung , Cheon Jung Hwa , Kim Joon
Published: January 2012

Continuous and direct measurement of evapotranspiration (ET) by the eddy covariance (EC) technique is still a challenge under monsoon climate because of a considerable amount of missing data during the long rainy periods and the consequential gap-filling process. Under such wet canopy conditions, especially in forests, evaporation of the intercepted precipitation (EWC) contributes significantly to the total ET. To quantify the role of EWC, leaf wetness has been measured at multiple levels in the canopy simultaneously with eddy covariance measurements at the KoFlux Gwangneung deciduous and coniferous forests for the entire year from September 2007 to August 2008. In this study, the measured EWC and the controlling mechanism during the wet canopy conditions have been scrutinized. Based on the evaluation of the four different algorithms of EWC estimation, that of the variable infiltration capacity (VIC) land surface model (LSM) has been adopted. All the missing EWC data are then recalculated by using the algorithm of VIC LSM and compared against the traditionally gap-filled EWC data based on the modified lookup table (MLT) method. The latter consistently underestimated EWC on average by 39% in deciduous forest and by 28% in coniferous forest. Major causes of such differences were due to the failure of considering aerodynamic coupling, advection of sensible heat, and heat storage in the MLT-based gap-filling method. Accordingly, a new gap-filling strategy for EWC is proposed that takes proper controlling mechanisms into account.
Estimating the Accuracy of Polarimetric Radar–Based Retrievals of Drop-Size Distribution Parameters and Rain Rate: An Application of Error Variance Separation Using Radar-Derived Spatial Correlations
Authors: Thurai M. , Bringi V. N. , Carey L. D. , Gatlin P. , Schultz E. , Petersen W. A.
Published: January 2012

The accuracy of retrieving the two drop size distribution (DSD) parameters, median volume diameter (D0), and normalized intercept parameter (NW), as well as rain rate (R), from polarimetric C-band radar data obtained during a cool-season, long-duration precipitation event in Huntsville, Alabama, is examined. The radar was operated in a special “near-dwelling” mode over two video disdrometers (2DVD) located 15 km away. The polarimetric radar–based retrieval algorithms for the DSD parameters and rain rate were obtained from simulations using the 2DVD measurements of the DSD. A unique feature of this paper is the radar-based estimation of the spatial correlation functions of the two DSD parameters and rain rate that are used to estimate the “point-to-area” variance. A detailed error variance separation is performed, including the aforementioned point-to-area variance, along with variance components due to the retrieval algorithm error, radar measurement error, and disdrometer sampling error. The spatial decorrelation distance was found to be smallest for the R (4.5 km) and largest for D0 (8.24 km). For log10(NW), it was 7.22 km. The proportion of the variance of the difference between radar-based estimates and 2DVD measurements that could be explained by the aforementioned errors was 100%, 57%, and 73% for D0, log10(NW), and R, respectively. The overall accuracy of the radar-based retrievals for the particular precipitation event quantified in terms of the fractional standard deviation were estimated to be 6.8%, 6%, and 21% for D0, log10(NW), and R, respectively. The normalized bias was <1%. These correspond to time resolution of ~3 min and spatial resolution of ~1.5 km.
Role of Endogenous Estrogen on the Incidence of Coronary Heart Disease in Men
Authors: Zheng Hongyun , Li Yan , Dai Wen , Wei Chuandong , Sun Kaisheng , Tong Yongqing
Published: January 2012

Estrogens protect the vascular system in women, but its effect in men is unclear. We evaluated the impact of estrogen on the male cardiovascular system. Of 140 Chinese males, 55 (aged 61.2 ± 3.5) were cases and 60 (aged 59.5 ± 4.6) were controls. Compared with the control group, only serum estradiol ([E2]; P < .01) levels but not testosterone ([T]; P = .21) were significantly lower in the cases. Linear and multiple regression analysis showed that serum T was positively associated with triglycerides ([TG]; r = .439, P < .01) and d-dimer ( r = .258, P < .05) but negatively associated with high-density lipoprotein cholesterol (HDL-C) levels ( r = −.267, P < .05) and C-reactive protein (CRP; r = −.214, P < .05). Estradiol was highly associated with TG ( r = .783, P < .01) and HDL-C ( r = .515, P < .01) but was negatively related with low-density lipoprotein cholesterol (LDL-C; P < .05), total cholesterol/HDL-C ( P < .05), CRP ( P < .01), and d-dimer ( P < .01). In conclusion, serum E2 and T levels affect coronary heart disease risk factors in males.
Working under intensive surveillance: When does ‘measuring everything that moves’ become intolerable?
Authors: Sewell Graham , Barker James R , Nyberg Daniel
Published: January 2012

We examine how call-center employees draw on opposed discourses to understand the purpose and consequences of performance measurement as workplace surveillance. Sometimes the workers saw performance measurement as a legitimate and impartial managerial tool serving the interests of everyone in the organization (e.g. by exposing free-riding, etc.). Other times, they saw performance measurement as intrusive and oppressive; imposed on them by managers who, as agents of employers, used it to serve a narrow set of interests (e.g. by intensifying work, etc.). Our analysis depicts how employees used an ironical process of predicate logic to develop flexible meaning-making strategies to cope with the apparent conflicts in meaning that arose from the two opposed discourses. We conclude by developing a three step method for the practical analysis of such ironical situations of competing discourses that facilitates our ability to reconsider and reconfigure meaning in more useful ways.
Power, institutions and the cross-national transfer of employment practices in multinationals
Authors: Ferner Anthony , Edwards Tony , Tempel Anne
Published: January 2012

This article argues for the systematic incorporation of power and interests into analysis of the cross-border transfer of practices within multinational companies (MNCs). Using a broadly Lukesian perspective on power it is argued that the transfer of practices involves different kinds of power capabilities through which MNC actors influence their institutional environment both at the ‘macro-level’ of host institutions and the ‘micro-level’ of the MNC itself. The incorporation of an explicit account of the way power interacts with institutions at different levels, it is suggested, underpins a more convincing account of transfer than is provided by the dominant neoinstitutionalist perspective in international business, and leads to a heuristic model capable of generating proposed patterns of transfer outcomes that may be tested empirically in future research.
Effect of combined flame retardant, liquid repellent and softener finishes on poly(lactic acid) (PLA) fabric performance
Authors: Avinc Ozan , Day Rebecca , Carr Chris , Wilding Mike
Published: January 2012

The effect of flame retardant and oil/water repellent finishes on the performance and colour of poly(lactic acid) fabrics was examined, and the influence of sequential and combined finishing applications was determined. A range of drying and curing application conditions were evaluated for imparting a durable flame-retardant effect (based on a mixture of cyclic phosphonate esters) to the poly(lactic acid) fabrics. The best application conditions for applying the flame retardent with a fluorochemical and softener/lubricant, without causing significant colour change and deterioration in handle properties, was drying by 110°C followed by thermofixation at 135°C for 90 s. The flame-retardant performance of the poly(lactic acid) fabrics was found to be durable even after 50 washing cycles and the application of three different finishing chemicals (flame retardant, fluorochemical and softener/lubricant) in the same bath did not adversely affect either theflame-retardant performance or colour change of the poly(lactic acid) fabrics. Combined bath applications were preferred over separate bath applications due to the lower colour change and it was also found that the softener/lubricant used in this study had a deleterious effect on oil repellency recovery performance after hot pressing.
Reexamining the Relationship Between Audit and Nonaudit Fees
Authors: Chan Lilian , Chen Tai-Yuan , Janakiraman Surya , Radhakrishnan Suresh
Published: January 2012

The authors introduce some new econometric tests and techniques for identifying and overcoming the problem of weak instruments in the context of joint provision of audit and nonaudit fees. The authors use this context because identifying appropriate instruments is difficult due to the lack of theoretical guidance as well as due to the difficulty in intuitively identifying instruments that satisfy the econometric requirements. The authors introduce a battery of empirical tests based on recent developments in econometrics to test for the appropriateness of the instruments. The authors then illustrate two approaches of using instruments from existing data: the size industry average portfolio approach and the synthetic-instrument approach. Although the approach using synthetic instruments sidesteps issues of identifying proxies with desirable properties, it requires some stringent assumptions that cannot be directly tested. However, as a methodological alternative, this approach can be used for robustness tests. The authors find that when the instruments are not weak, audit and nonaudit fees are positively associated. This relationship holds for audit and tax-related nonaudit fees as well. Overall, the evidence suggests the existence of economies of scope benefits from the joint supply of audit and nonaudit services. Methodologically, the authors illustrate the importance of testing the appropriateness of the instruments utilized when accounting for endogeneity.