bluuebunny/crossref_metadata_2025 huggingface dataset:
How to ReconditionEx VivoInitially Rejected Donor Lungs for Clinical Transplantation: Clinical Experience from Lund University Hospital
Authors: Lindstedt Sandra , Eyjolfsson Atli , Koul Bansi , Wierup Per , Pierre Leif , Gustafsson Ronny , Ingemansson Richard
Published: August 2011

A major problem in clinical lung transplantation is the shortage of donor lungs. Only about 20% of donor lungs are accepted for transplantation. We have recently reported the results of the first six double lung transplantations performed with donor lungs reconditionedex vivothat had been deemed unsuitable for transplantation by the Scandiatransplant, Eurotransplant, and UK Transplant organizations because the arterial oxygen pressure was less than 40 kPa. The three-month survival of patients undergoing transplant with these lungs was 100%. One patient died due to sepsis after 95 days, and one due to rejection after 9 months. Four recipients are still alive and well 24 months after transplantation, with no signs of bronchiolitis obliterans syndrome. The donor lungs were reconditionedex vivoin an extracorporeal membrane oxygenation circuit using STEEN solution mixed with erythrocytes, to dehydrate edematous lung tissue. Functional evaluation was performed with deoxygenated perfusate at different inspired fractions of oxygen. The arterial oxygen pressure was significantly improved in this model. Thisex vivoevaluation model is thus a valuable addition to the armamentarium in increasing the number of acceptable lungs in a donor population with inferior arterial oxygen pressure values, thereby, increasing the lung donor pool for transplantation. In the following paper we present our clinical experience from the first six patients in the world. We also present the technique we used in detail with flowchart.
The Humpbacked Species Richness-Curve: A Contingent Rule for Community Ecology
Authors: Graham John H. , Duda Jeffrey J.
Published: August 2011

Functional relationships involving species richness may be unimodal, monotonically increasing, monotonically decreasing, bimodal, multimodal, U-shaped, or with no discernable pattern. The unimodal relationships are the most interesting because they suggest dynamic, nonequilibrium community processes. For that reason, they are also contentious. In this paper, we provide a wide-ranging review of the literature on unimodal (humpbacked) species richness-relationships. Though not as widespread as previously thought, unimodal patterns of species richness are often associated with disturbance, predation and herbivory, productivity, spatial heterogeneity, environmental gradients, time, and latitude. These unimodal patterns are contingent on organism and environment; we examine unimodal species richness-curves involving plants, invertebrates, vertebrates, plankton, and microbes in marine, lacustrine, and terrestrial habitats. A goal of future research is to understand the contingent patterns and the complex, interacting processes that generate them.
Modeling of Photoconductivity of Porous Silicon
Authors: Monastyrskii L. S. , Sokolovskii B. S. , Pavlyk M. R. , Parandii P. P.
Published: August 2011

The paper investigates a model of the photoconductivity of macroporous silicon in the conditions of homogeneous generation of photocarriers. By the finite element method, the stationary photoconductivity and the time evolution of photoconductivity after instantaneous shutdown of light are calculated. Dependences of the stationary photoconductivity and relaxation time of photoconductivity on the velocity of recombination of nonequilibrium carriers at the surfaces of pores, radius of pores, and average distance between them are analyzed.
Prenatal Diagnosis of Congenital Mesenchymal Hamartoma of Liver: A Case Report
Authors: Kodandapani Sreelakshmi , Pai Muralidhar V. , Kumar Vijay , Pai Kanthilatha V.
Published: August 2011

Hepatic mesenchymal hamartoma is a rare benign tumor. We present an unusual case of a fetal abdominal cyst, later diagnosed histopathologically to be mesenchymal hamartoma of liver. The organ of origin was indeterminate on both prenatal and postnatal ultrasounds. As there are no specific sonological findings, whenever a large multicystic fetal abdominal cyst is seen, mesenchymal hamartoma should be considered as a possibility.
Infected Thyroglossal Duct Cyst Involving Submandibular Region: A Case Report
Authors: Gandhi Rahul A. , Bhowate Rahul , Degweker Shirish , Bhake Arvind
Published: August 2011

Thyroglossal duct cyst presents most frequently in the midline of the neck, either at or just below the level of the hyoid bone. They generally manifest as painless neck swelling, and they move on protrusion of tongue and during swallowing. A case of thyroglossal cyst was reported in the left submandibular region in a 14-year-old girl, above the level of hyoid bone; ultrasound examination favored a cystic lesion which moved in a vertical fashion on swallowing whereas fine needle aspiration cytology report was suggestive of simple cystic lesion of thyroglossal cyst. No lymphoid or malignant cells were present. The cyst was excised completely by surgical procedure under general anesthesia. Histopathological analysis revealed thyroglossal cyst showing columnar and flattened epithelium of cyst with focal aggregate of chronic inflammatory cells supported by fibrocollagenous cyst wall. The clinical, ultrasound, and histopathological findings suggested that the lesion was an infected thyroglossal cyst. There was no evidence of recurrence 6 months after surgery.
Targeting the Tumor Microenvironment: Focus on Angiogenesis
Authors: Fan Fengjuan , Schimming Alexander , Jaeger Dirk , Podar Klaus
Published: August 2011

Tumorigenesis is a complex multistep process involving not only genetic and epigenetic changes in the tumor cell but also selective supportive conditions of the deregulated tumor microenvironment. One key compartment of the microenvironment is the vascular niche. The role of angiogenesis in solid tumors but also in hematologic malignancies is now well established. Research on angiogenesis in general, and vascular endothelial growth factor in particular, is a major focus in biomedicine and has led to the clinical approval of several antiangiogenic agents including thalidomide, bevacizumab, sorafenib, sunitinib, pazopanib, temesirolimus, and everolimus. Indeed, antiangiogenic agents have significantly changed treatment strategies in solid tumors (colorectal cancer, renal cell carcinoma, and breast cancer) and multiple myeloma. Here we illustrate important aspects in the interrelationship between tumor cells and the microenvironment leading to tumor progression, with focus on angiogenesis, and summarize derived targeted therapies.
TGF-β/SMAD/GLI2 Signaling Axis in Cancer Progression and Metastasis
Authors: Javelaud Delphine , Alexaki Vasileia I. , Dennler Sylviane , Mohammad Khalid S. , Guise Theresa A. , Mauviel Alain
Published: August 2011

The Hedgehog (HH) and TGF-β signaling pathways represent essential regulators of cell proliferation and differentiation during embryogenesis. Pathway deregulation is a characteristic of various cancers. Recently, evidence for a convergence of these pathways at the level of the GLI2 transcription factor in the context of tumor initiation and progression to metastasis has emerged. This short review summarizes recent knowledge about GLI2 function and mechanisms of action downstream of TGF-β in cancer. Cancer Res; 71(17); 5606–10. ©2011 AACR.
p38γ Promotes Breast Cancer Cell Motility and Metastasis through Regulation of RhoC GTPase, Cytoskeletal Architecture, and a Novel Leading Edge Behavior
Authors: Rosenthal Devin T. , Iyer Harish , Escudero Silvia , Bao Liwei , Wu Zhifen , Ventura Alejandra C. , Kleer Celina G. , Arruda Ellen M. , Garikipati Krishna , Merajver Sofia D.
Published: August 2011

Understanding the molecular alterations that confer cancer cells with motile, metastatic properties is needed to improve patient survival. Here, we report that p38γ motogen-activated protein kinase regulates breast cancer cell motility and metastasis, in part, by controlling expression of the metastasis-associated small GTPase RhoC. This p38γ–RhoC regulatory connection was mediated by a novel mechanism of modulating RhoC ubiquitination. This relationship persisted across multiple cell lines and in clinical breast cancer specimens. Using a computational mechanical model based on the finite element method, we showed that p38γ-mediated cytoskeletal changes are sufficient to control cell motility. This model predicted novel dynamics of leading edge actin protrusions, which were experimentally verified and established to be closely related to cell shape and cytoskeletal morphology. Clinical relevance was supported by evidence that elevated expression of p38γ is associated with lower overall survival of patients with breast cancer. Taken together, our results offer a detailed characterization of how p38γ contributes to breast cancer progression. Herein we present a new mechanics-based analysis of cell motility, and report on the discovery of a leading edge behavior in motile cells to accommodate modified cytoskeletal architecture. In summary, these findings not only identify a novel mechanism for regulating RhoC expression but also advance p38γ as a candidate therapeutic target. Cancer Res; 71(20); 6338–49. ©2011 AACR.
Novel Cryo-Imaging of the Glioma Tumor Microenvironment Reveals Migration and Dispersal Pathways in Vivid Three-Dimensional Detail
Authors: Burden-Gulley Susan M. , Qutaish Mohammed Q. , Sullivant Kristin E. , Lu Hong , Wang Jing , Craig Sonya E.L. , Basilion James P. , Wilson David L. , Brady-Kalnay Susann M.
Published: August 2011

Traditional methods of imaging cell migration in the tumor microenvironment include serial sections of xenografts and standard histologic stains. Current molecular imaging techniques suffer from low resolution and difficulty in imaging through the skull. Here we show how computer algorithms can be used to reconstruct images from tissue sections obtained from mouse xenograft models of human glioma and can be rendered into three-dimensional images offering exquisite anatomic detail of tumor cell dispersal. Our findings identify human LN-229 and rodent CNS-1 glioma cells as valid systems to study the highly dispersive nature of glioma tumor cells along blood vessels and white matter tracts in vivo. This novel cryo-imaging technique provides a valuable tool to evaluate therapeutic interventions targeted at limiting tumor cell invasion and dispersal. Cancer Res; 71(17); 5932–40. ©2011 AACR.
Estrogen-Dependent Gene Transcription in Human Breast Cancer Cells Relies upon Proteasome-Dependent Monoubiquitination of Histone H2B
Authors: Prenzel Tanja , Begus-Nahrmann Yvonne , Kramer Frank , Hennion Magali , Hsu Chieh , Gorsler Theresa , Hintermair Corinna , Eick Dirk , Kremmer Elisabeth , Simons Mikael , Beissbarth Tim , Johnsen Steven A.
Published: August 2011

The estrogen receptor-α (ERα) determines the phenotype of breast cancers where it serves as a positive prognostic indicator. ERα is a well-established target for breast cancer therapy, but strategies to target its function remain of interest to address therapeutic resistance and further improve treatment. Recent findings indicate that proteasome inhibition can regulate estrogen-induced transcription, but how ERα function might be regulated was uncertain. In this study, we investigated the transcriptome-wide effects of the proteasome inhibitor bortezomib on estrogen-regulated transcription in MCF7 human breast cancer cells and showed that bortezomib caused a specific global decrease in estrogen-induced gene expression. This effect was specific because gene expression induced by the glucocorticoid receptor was unaffected by bortezomib. Surprisingly, we observed no changes in ERα recruitment or assembly of its transcriptional activation complex on ERα target genes. Instead, we found that proteasome inhibition caused a global decrease in histone H2B monoubiquitination (H2Bub1), leading to transcriptional elongation defects on estrogen target genes and to decreased chromatin dynamics overall. In confirming the functional significance of this link, we showed that RNA interference–mediated knockdown of the H2B ubiquitin ligase RNF40 decreased ERα-induced gene transcription. Surprisingly, RNF40 knockdown also supported estrogen-independent cell proliferation and activation of cell survival signaling pathways. Most importantly, we found that H2Bub1 levels decrease during tumor progression. H2Bub1 was abundant in normal mammary epithelium and benign breast tumors but absent in most malignant and metastatic breast cancers. Taken together, our findings show how ERα activity is blunted by bortezomib treatment as a result of reducing the downstream ubiquitin-dependent function of H2Bub1. In supporting a tumor suppressor role for H2Bub1 in breast cancer, our findings offer a rational basis to pursue H2Bub1-based therapies for future management of breast cancer. Cancer Res; 71(17); 5739–53. ©2011 AACR.
Aging in Autism Spectrum Disorders: A Mini-Review
Authors: Happé Francesca , Charlton Rebecca A.
Published: August 2011

This article addresses an important and barely researched topic: what happens to children with autism spectrum disorders when they grow old. We review the small published literature on aging in autism. We then consider the relevance of research on ‘neurotypical’ aging in core domains of autistic impairment: social cognition, executive function, cognitive style and memory. Research themes from the study of normal aging, including cognitive reserve, compensation, quality of life, loneliness and physical health are of relevance for future research on autism. Studies of aging in autism will be important not only to plan appropriate services, but also to shed light on the full developmental trajectory of this neurodevelopmental condition, and perhaps provide clues to neuropathology and etiology.
Bacteriologic Evaluation of Sinus Aspirates Taken by Balloon Catheter Devices in Chronic Rhinosinusitis: Preliminary Study
Authors: Ikeda Katsuhisa , Ono Noritsugu , Iizuka Takashi , Kase Kaori , Minekawa Akira , Inoshita Ayako , Kusunoki Takeshi
Published: August 2011

Purpose: Chronic rhinosinusitis (CRS) is known to be a polymicrobial infection involving both aerobes and Gram-positive and Gram-negative anaerobes. Accurate bacterial evaluation by adequate culture methods can justify subsequent antimicrobial strategies. Methods: Two specimens were obtained from each of 10 patients undergoing catheter-based Balloon Sinuplasty™, one from the middle meatus (endoscopic approach) and the other from the sinus (catheter-based approach). Results: The bacterial culture from the middle meatus was positive in 9 of 10 patients, including 6 different aerobes without anaerobes. The bacterial culture of aspirates from the sinuses were positive in 8 out of 10 patients, with 4 different aerobic bacteria and 4 different anaerobic bacteria. Anaerobes were isolated in 0% of middle meatus samples, which was significantly lower than the 62.5% (5/8) detected in the sinus samples. Conclusions: Bacterial culture of sinus aspirates using a catheter-based technique improves the recovery of bacterial pathogens from CRS patients.
Influence of Variation in the Follicle-Stimulating Hormone Receptor Gene (FSHR) and Age at Menopause on the Development of Alzheimer’s Disease in Women
Authors: Corbo Rosa Maria , Gambina Giuseppe , Broggio Elisabetta , Scacchi Renato
Published: August 2011

Background: The higher prevalence of sporadic Alzheimer’s disease (AD) in women may be explained by their longer life expectancy, but also by biological gender-specific factors such as a woman’s past fertility. Methods: We investigated the relationship between fertility and susceptibility to AD in women by studying two polymorphisms at codons 307 and 680 of the follicle-stimulating hormone receptor gene (FSHR) involved in determining human fertility. The role of age at menopause (AM) as a gender-specific AD susceptibility determinant was also examined. The study population comprised 291 AD patients (70.1% women) and 134 controls (63.4% women). Results: Logistic regression analysis showed that only among the women the FSHR AS/AS genotype was associated with a significantly lower risk of AD (OR = 0.36, 95% CI: 0.15–0.85), suggesting a gender-specific protective role of the FSHR genotype against AD susceptibility. A lower age at natural menopause was observed in the AD patients (49.7 ± 2.53) than in the controls (50.7 ± 2.53, p = 0.02) and on linear regression analysis an association emerged between an earlier AM and an earlier AD onset (p = 0.004). Conclusions: Genetic and non-genetic gender-specific factors may contribute to the AD pathogenesis in women, although further investigations are required to clarify their actual role.
A Blood-Based Algorithm for the Detection of Alzheimer’s Disease
Authors: O’Bryant Sid E. , Xiao Guanghua , Barber Robert , Reisch Joan , Hall James , Cullum C. Munro , Doody Rachelle , Fairchild Thomas , Adams Perrie , Wilhelmsen Kirk , Diaz-Arrastia Ramon ,   Texas Alzheimer’s Research and Care Consortium
Published: August 2011

Background: We previously created a serum-based algorithm that yielded excellent diagnostic accuracy in Alzheimer’s disease. The current project was designed to refine that algorithm by reducing the number of serum proteins and by including clinical labs. The link between the biomarker risk score and neuropsychological performance was also examined. Methods: Serum-protein multiplex biomarker data from 197 patients diagnosed with Alzheimer’s disease and 203 cognitively normal controls from the Texas Alzheimer’s Research Consortium were analyzed. The 30 markers identified as the most important from our initial analyses and clinical labs were utilized to create the algorithm. Results: The 30-protein risk score yielded a sensitivity, specificity, and AUC of 0.88, 0.82, and 0.91, respectively. When combined with demographic data and clinical labs, the algorithm yielded a sensitivity, specificity, and AUC of 0.89, 0.85, and 0.94, respectively. In linear regression models, the biomarker risk score was most strongly related to neuropsychological tests of language and memory. Conclusions: Our previously published diagnostic algorithm can be restricted to only 30 serum proteins and still retain excellent diagnostic accuracy. Additionally, the revised biomarker risk score is significantly related to neuropsychological test performance.
Age- and Sex-Specific Trends in the Incidence of Hospitalized Acute Coronary Syndromes in Western Australia
Authors: Nedkoff Lee J. , Briffa Tom G. , Preen David B. , Sanfilippo Frank M. , Hung Joseph , Ridout Stephen C. , Knuiman Matthew , Hobbs Michael
Published: August 2011

Background—

The incidence of myocardial infarction has declined during the past 4 decades in many populations. However, there are limited population data measuring trends in acute coronary syndromes (ACS). We therefore examined temporal trends in the incidence of hospitalized ACS by age and sex in a population-based cohort.

Methods and Results—

The Western Australian Data Linkage System, a repository of linked administrative health data, was used to identify 29 421 incident ACS hospitalizations between 1996 and 2007. Poisson log-linear regression models were used to calculate incidence rate changes. Age-standardized incidence rates of ACS declined annually in men by 1.7% (95% confidence interval [CI], −2.1 to −1.3) and in women by 1.6% (95% CI, −2.1 to −1.0). These declining rates were underpinned by annual reductions in the incidence of unstable angina (men, −3.0%; 95% CI, −3.7 to −2.4; women, −2.5; 95% CI, −3.3 to −1.7), whereas annual changes in myocardial infarction incidence were less (men, −1.0%; 95% CI, −1.5 to −0.5; women, −0.8%; 95% CI, −1.6 to 0). However, the overall trends masked age group differences, with ACS incidence increasing annually in 35- to 54-year-old women (2.3%; 95% CI, 1.0 to 3.8), predominantly driven by increasing incidence of myocardial infarction.

Conclusions—

The age-standardized incidence of ACS decreased significantly in Western Australia from 1996 to 2007. However, an increase in ACS incidence in women ages 35 to 54 years is troubling and warrants further investigation.
Breaks in Presence in Virtual Environments: An Analysis of Blood Flow Velocity Responses
Authors: Rey Beatriz , Parkhutik Vera , Alcañiz Mariano
Published: August 2011

One of the techniques used to monitor variations in presence during a virtual reality experience is the analysis of breaks in presence (BIPs). Previous studies have monitored peripheral physiological responses during BIPs in order to find a characteristic physiological response. In this work, blood flow velocity (BFV) in middle cerebral arteries (MCAs) has been monitored using transcranial Doppler ultrasound during the exposure to a virtual environment. Two BIPs of different intensity were forced during the virtual reality experience. Variations in BFV during each BIP and during the recovery periods that followed them have been analyzed. A decreasing trend was observed in BFV signal during the most intense BIP in most subjects. However, during the less intense BIP an oscillating behavior was observed. Significant differences have been found between the maximum percentage variations observed in each BIP. During the recovery periods, an increasing trend was observed. The mean response times (time elapsed since the beginning of the period until the maximum percentage variation in the period occured) ranged between 10.116 s and 12.774 s during the BIPs, and between 11.025 s and 13.345 during the recovery periods, depending on the vessel and on the kind of BIP.
Sources of Spread in Multimodel Projections of the Greenland Ice Sheet Surface Mass Balance
Authors: Yoshimori Masakazu , Abe-Ouchi Ayako
Published: August 2011

The many studies investigating the future change of the Greenland Ice Sheet surface mass balance from climate model output exhibit a wide range of projections. This study makes projections from the Coupled Model Intercomparison Project phase 3 models used in the Intergovernmental Panel on Climate Change Fourth Assessment Report and explores the underlying physical processes behind their spread. The projections are made for three Special Report on Emissions Scenarios, B1, A1B, and A2, with a focused analysis on the A1B scenario. The estimate in the study suggests that about 60% of the intermodel difference in the twenty-first-century ablation rate change under the A1B scenario is accounted for by the global annual mean temperature change. In the current study, other processes responsible for the spread in model projections are investigated after excluding this global effect. A negative correlation (−0.60) was found between the simulated summer temperature bias over the Greenland Ice Sheet under present-day conditions and the ablation rate increase during the twenty-first century, partly because maximum warming over ice is approximately limited to the melting temperature. Models with relatively larger ablation rate increases during the twenty-first century exhibit greater warming with a greater reduction in sea ice cover. The authors found that these models also simulate relatively cooler summer conditions in high latitudes with more sea ice cover in the late twentieth century, suggesting the importance of sea ice feedbacks. Also, an anticorrelation (−0.75) is found between weakening of the Atlantic meridional overturning circulation and the ablation rate increase during the twenty-first century. The relation in the model spread between the twenty-first-century ablation change and the late twentieth-century climate conditions is then used to investigate the impact of model bias on the multimodel ensemble of projections. The result suggests that the models’ underestimation of present-day sea ice concentration near the coast of Greenland may cause an underestimation of future Greenland Ice Sheet ablation rate increase in the ensemble projection. These results emphasize the importance of correctly simulating present-day conditions and understanding the underlying multiple physical processes behind the intermodel difference to reduce the uncertainty in future projections.
Spatial Variation in Turbulent Heat Fluxes in Drake Passage
Authors: Jiang ChuanLi , Gille Sarah T. , Sprintall Janet , Yoshimura Kei , Kanamitsu Masao
Published: August 2011

High-resolution underway shipboard atmospheric and oceanic observations collected in Drake Passage from 2000 to 2009 are used to examine the spatial scales of turbulent heat fluxes and flux-related state variables. The magnitude of the seasonal cycle of sea surface temperature (SST) south of the Polar Front is found to be twice that north of the front, but the seasonal cycles of the turbulent heat fluxes show no differences on either side of the Polar Front. Frequency spectra of the turbulent heat fluxes and related variables are red, with no identifiable spectral peaks. SST and air temperature are coherent over a range of frequencies corresponding to periods between ~10 h and 2 days, with SST leading air temperature. The spatial decorrelation length scales of the sensible and latent heat fluxes calculated from two-day transects are 65 ± 6 km and 80 ± 6 km, respectively. The scale of the sensible heat flux is consistent with the decorrelation scale for air–sea temperature differences (70 ± 6 km) rather than either SST (153 ± 2 km) or air temperature (138 ± 4 km) alone. These scales are dominated by the Polar Front. When the Polar Front region is excluded, the decorrelation scales are 10–20 km, consistent with the first baroclinic Rossby radius.

These eddy scales are often unrepresented in the available gridded heat flux products. The Drake Passage ship measurements are compared with four recently available gridded turbulent heat flux products: the European Centre for Medium-Range Weather Forecasts high-resolution operational product in support of the Year of Coordinated Observing Modeling and Forcasting Tropical Convection (ECMWF-YOTC), ECMWF interim reanalysis (ERA-Interim), the Drake Passage reanalysis downscaling (DPRD10) regional product, and the objectively analyzed air–sea fluxes (OAFlux). The decorrelation length scales of the air–sea temperature difference, wind speed, and turbulent heat fluxes from these four products are significantly larger than those determined from shipboard measurements.
Can We See the Wind? Statistical Downscaling of Historical Sea Surface Winds in the Subarctic Northeast Pacific
Authors: Monahan Adam H.
Published: August 2011

The statistical predictability of wintertime (December–February) monthly-mean sea surface winds (both vector wind components and wind speed) in the subarctic northeast Pacific off the west coast of Canada is considered, in the context of surface wind downscaling. Predictor fields (zonal wind, meridional wind, wind speed, and temperature) are shown to carry predictive information on the large scales (both vertical and horizontal) that are well simulated by numerical weather prediction and global climate models. It is found that, in general, the monthly mean vector wind components are more predictable by indices of the large-scale flow than by the monthly mean wind speed, with no systematic vertical variation in predictive skill for either across the depth of the troposphere. The difference in predictive skill between monthly-mean vector wind components and wind speed is interpreted in terms of an idealized model of the vector wind speed probability distribution, which demonstrates that for the conditions in the subarctic northeast Pacific, the sensitivity of mean wind speed to the standard deviations of vector wind component fluctuations (which are not well predicted) is greater than that to the mean vector wind components. It is demonstrated that this sensitivity is state dependent, and it is suggested that monthly mean wind speeds may be inherently more predictable in regions where the sensitivity to the vector wind component means is greater than that to the standard deviations. It is also demonstrated that daily wind fluctuations (both vector wind and wind speed) are generally more predictable than monthly-mean variability, and that monthly averages of the predicted daily winds generally represent the monthly-mean surface winds better than the predictions directly from monthly mean predictors.
Quantifying the Predictive Skill in Long-Range Forecasting. Part I: Coarse-Grained Predictions in a Simple Ocean Model
Authors: Giannakis Dimitrios , Majda Andrew J.
Published: August 2011

An information-theoretic framework is developed to assess the long-range coarse-grained predictive skill in a perfect-model environment. Central to the scheme is the notion that long-range forecasting involves regimes; specifically, that the appropriate initial data for ensemble prediction is the affiliation of the system to a coarse-grained partition of phase space representing regimes. The corresponding ensemble prediction probabilities, which are computable using ergodic signals from the model, are then used to quantify through relative entropy the information beyond climatology in the partition. As an application, the authors study the predictability of circulation regimes in an equivalent barotropic double-gyre ocean model using a partition algorithm based on K-means clustering and running-average coarse graining. Besides the established rolled up and extensional phases of the eastward jet, optimal partitions for triennial-scale forecasts feature a jet configuration dominated by the second empirical orthogonal function (EOF) of the streamfunction, as well as phases in which the jet interacts with eddies in higher EOFs. Due to mixing dynamics, the skill beyond three-state models is lost for forecast lead times longer than three years, but significant skill remains in the energy and the leading principal component of the streamfunction for septennial forecasts.
African Easterly Jet: Barotropic Instability, Waves, and Cyclogenesis
Authors: Wu Man-Li C. , Reale Oreste , Schubert Siegfried D. , Suarez Max J. , Thorncroft Chris D.
Published: August 2011

This study investigates the structure of the African easterly jet, focusing on instability processes on a seasonal and subseasonal scale, with the goal of identifying features that could provide increased predictability of Atlantic tropical cyclogenesis. The Modern-Era Retrospective Analysis for Research and Applications (MERRA) is used as the main investigating tool. MERRA is compared with other reanalyses datasets from major operational centers around the world and was found to describe very effectively the circulation over the African monsoon region. In particular, a comparison with precipitation datasets from the Global Precipitation Climatology Project shows that MERRA realistically reproduces seasonal precipitation over that region. The verification of the generalized Kuo barotropic instability condition computed from seasonal means is found to have the interesting property of defining well the location where observed tropical storms are detected. This property does not appear to be an artifact of MERRA and is present also in the other adopted reanalysis datasets. Therefore, the fact that the areas where the mean flow is unstable seems to provide a more favorable environment for wave intensification, could be another factor to include—in addition to sea surface temperature, vertical shear, precipitation, the role of Saharan air, and others—among large-scale forcings affecting development and tropical cyclone frequency. In addition, two prominent modes of variability are found based on a spectral analysis that uses the Hilbert–Huang transform: a 2.5–6-day mode that corresponds well to the African easterly waves and also a 6–9-day mode that seems to be associated with tropical–extratropical interaction.
Quantifying the Volunteer Effort of Scientific Peer Reviewing
Authors: Golden Mary , Schultz David M.
Published: August 2011

A survey of 310 reviewers for Monthly Weather Review addresses how much time and effort goes into the peer-review process and provides insight into how reviewers function. Using these data, the individual and collective contributions of volunteer peer reviewers to the peer-review process can be determined. Individually, respondents to the survey review an average of 2 manuscripts a year for Monthly Weather Review, 4 manuscripts a year for AMS journals, and 8 manuscripts a year in total, although some review more than 20 manuscripts a year. Each review takes an average of 9.6 h. Summing the individual contributions of the reviewers, respondents averaged 18 h yr−1 performing reviews for Monthly Weather Review, 36 h yr−1 for AMS journals, and 63 h yr−1 for all journals. The collective time that all of the reviewers put into the peer-review process for all manuscripts submitted to Monthly Weather Review for each year amounts to 362,179 h, or more than 4 years of voluntary labor valued at over $2.34 million. Nearly all respondents (95%) are comfortable with their current load, but only 30% said that they would be willing to perform more reviews. Because the number of submissions to journals has been increasing over time and is unlikely to decrease in the near future, this burden is anticipated to grow. Options for reducing the burden include using fewer reviewers per manuscript, increasing the number of unilateral decisions made by editors, and increasing the size of the reviewer pool (particularly from active retired and early-career scientists).
Empirical Downscaling of High-Resolution Regional Precipitation from Large-Scale Reanalysis Fields
Authors: Nicholas Robert E. , Battisti David S.
Published: August 2011

This study describes an EOF-based technique for statistical downscaling of high-spatial-resolution monthly-mean precipitation from large-scale reanalysis circulation fields. The method is demonstrated and evaluated for four widely separated locations: the southeastern United States, the upper Colorado River basin, China’s Jiangxi Province, and central Europe. For each location, the EOF-based downscaling models successfully reproduce the observed annual cycle while eliminating the biases seen in NCEP–NCAR reanalysis precipitation. They also frequently reproduce the monthly precipitation anomalies with greater fidelity than is seen in the precipitation field derived directly from reanalysis, and they outperform a suite of regional climate models over the two U.S. locations. With the relatively high skill achieved over a range of climate regimes, this technique may be a viable alternative to numerical downscaling of monthly-mean precipitation for many locations.
A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes
Authors: Fridlind Ann M. , van Diedenhoven Bastiaan , Ackerman Andrew S. , Avramov Alexander , Mrowiec Agnieszka , Morrison Hugh , Zuidema Paquita , Shupe Matthew D.
Published: August 2011

Observations of long-lived mixed-phase Arctic boundary layer clouds on 7 May 1998 during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE)–Arctic Cloud Experiment (ACE)/Surface Heat Budget of the Arctic Ocean (SHEBA) campaign provide a unique opportunity to test understanding of cloud ice formation. Under the microphysically simple conditions observed (apparently negligible ice aggregation, sublimation, and multiplication), the only expected source of new ice crystals is activation of heterogeneous ice nuclei (IN) and the only sink is sedimentation. Large-eddy simulations with size-resolved microphysics are initialized with IN number concentration NIN measured above cloud top, but details of IN activation behavior are unknown. If activated rapidly (in deposition, condensation, or immersion modes), as commonly assumed, IN are depleted from the well-mixed boundary layer within minutes. Quasi-equilibrium ice number concentration Ni is then limited to a small fraction of overlying NIN that is determined by the cloud-top entrainment rate we divided by the number-weighted ice fall speed at the surface υf. Because wc < 1 cm s−1 and υf > 10 cm s−1, Ni/NIN ≪ 1. Such conditions may be common for this cloud type, which has implications for modeling IN diagnostically, interpreting measurements, and quantifying sensitivity to increasing NIN (when we/υf < 1, entrainment rate limitations serve to buffer cloud system response). To reproduce observed ice crystal size distributions and cloud radar reflectivities with rapidly consumed IN in this case, the measured above-cloud NIN must be multiplied by approximately 30. However, results are sensitive to assumed ice crystal properties not constrained by measurements. In addition, simulations do not reproduce the pronounced mesoscale heterogeneity in radar reflectivity that is observed.
Does the Madden–Julian Oscillation Influence Wintertime Atmospheric Rivers and Snowpack in the Sierra Nevada?
Authors: Guan Bin , Waliser Duane E. , Molotch Noah P. , Fetzer Eric J. , Neiman Paul J.
Published: August 2011

The relationships between the Madden–Julian oscillation (MJO), activities of atmospheric rivers (ARs), and the resulting snowpack accumulation in the California Sierra Nevada, are analyzed based on 13 yr of observations for water years 1998–2010 inclusive. The AR activity, as measured by the number of high-impact ARs, mean per event snow water equivalent (SWE) changes, and the cumulative SWE changes, is shown to be significantly augmented when MJO convection is active over the far western tropical Pacific (phase 6 on the Wheeler–Hendon diagram). The timing of high-impact ARs (early- versus late-winter occurrences) also appears to be regulated by the MJO.

Total snow accumulation in the Sierra Nevada (i.e., AR and non-AR accumulation combined) is most significantly increased when MJO convection is active over the eastern Indian Ocean (phase 3), and reduced when MJO convection is active over the Western Hemisphere (phase 8), with the magnitude of the daily anomaly being roughly half the cold-season mean daily snow accumulation over many snow sensor sites. The positive (negative) SWE anomaly is accompanied by a cold (warm) surface air temperature (SAT) anomaly and an onshore (offshore) water vapor flux anomaly. The contrasting SAT anomaly patterns associated with MJO phases 3 and 8, revealed by the in situ observations, are more realistically represented in the Atmospheric Infrared Sounder retrievals than in the European Centre for Medium-Range Weather Forecasts Interim reanalysis.
A 5-yr Climatology of Tornado False Alarms
Authors: Brotzge J. , Erickson S. , Brooks H.
Published: August 2011

During 2008 approximately 75% of tornado warnings issued by the National Weather Service (NWS) were false alarms. This study investigates some of the climatological trends in the issuance of false alarms and highlights several factors that impact false-alarm ratio (FAR) statistics. All tornadoes and tornado warnings issued across the continental United States between 2000 and 2004 were analyzed, and the data were sorted by hour of the day, month of the year, geographical region and weather forecast office (WFO), the number of tornadoes observed on a day in which a false alarm was issued, distance of the warned area from the nearest NWS radar, county population density, and county area. Analysis of the tornado false-alarm data identified six specific trends. First, the FAR was highest during nonpeak storm periods, such as during the night and during the winter and late summer. Second, the FAR was strongly tied to the number of tornadoes warned per day. Nearly one-third of all false alarms were issued on days when no tornadoes were confirmed within the WFO’s county warning area. Third, the FAR varied with distance from radar, with significantly lower estimates found beyond 150 km from radar. Fourth, the FAR varied with population density. For warnings within 50 km of an NWS radar, FAR increased with population density; however, for warnings beyond 150 km from radar, FAR decreased regardless of population density. Fifth, the FAR also varied as a function of county size. The FAR was generally highest for the smallest counties; the FAR was ~80% for all counties less than 1000 km2 regardless of distance from radar. Finally, the combined effects of distance from radar, population density, and county size led to significant variability across geographic regions.
Evaluation of IRI’s Seasonal Climate Forecasts for the Extreme 15% Tails
Authors: Barnston Anthony G. , Mason Simon J.
Published: August 2011

This paper evaluates the quality of real-time seasonal probabilistic forecasts of the extreme 15% tails of the climatological distribution of temperature and precipitation issued by the International Research Institute for Climate and Society (IRI) from 1998 through 2009. IRI’s forecasts have been based largely on a two-tiered multimodel dynamical prediction system. Forecasts of the 15% extremes have been consistent with the corresponding probabilistic forecasts for the standard tercile-based categories; however, nonclimatological forecasts for the extremes have been issued sparingly. Results indicate positive skill in terms of resolution and discrimination for the extremes forecasts, particularly in the tropics. Additionally, with the exception of some overconfidence for extreme above-normal precipitation and a strong cool bias for temperature, reliability analyses suggest generally good calibration. Skills for temperature are generally higher than those for precipitation, due both to correct forecasts of increased probabilities of extremely high (above the upper 15th percentile) temperatures associated with warming trends, and to better discrimination of interannual variability. However, above-normal temperature extremes were substantially underforecast, as noted also for the IRI’s tercile forecasts.
Comparison between Low-Flash and Non-Lightning-Producing Convective Areas within a Mature Mesoscale Convective System
Authors: Palucki Jennifer L. , Biggerstaff Michael I. , MacGorman Donald R. , Schuur Terry
Published: August 2011

Two small multicellular convective areas within a larger mesoscale convective system that occurred on 20 June 2004 were examined to assess vertical motion, radar reflectivity, and dual-polarimetric signatures between flash and non-flash-producing convection. Both of the convective areas had similar life cycles and general structures. Yet, one case produced two flashes, one of which may have been a cloud-to-ground flash, while the other convective area produced no flashes. The non-lightning-producing case had a higher peak reflectivity up to 6 km. Hence, if a reflectivity-based threshold were used as a precursor to lightning, it would have yielded misleading results. The peak upward motion in the mixed-phase region for both cases was 8 m s−1 or less. However, the lightning-producing storm contained a wider region where the updraft exceeded 5 m s−1. Consistent with the broader updraft region, the lightning-producing case exhibited a distinct graupel signature over a broader region than the non-lightning-producing convection. Slight differences in vertical velocity affected the quantity of graupel present in the mixed-phase region, thereby providing the subtle differences in polarimetric signatures that were associated with lightning activity. If the results here are generally applicable, then graupel volume may be a better precursor to a lightning flash than radar reflectivity. With the dual-polarimetric upgrade to the national observing radar network, it should be possible to better distinguish between lightning- and non-lightning-producing areas in weak convective systems that pose a potential safety hazard to the public.
Surface Fronts, Troughs, and Baroclinic Zones in the Great Lakes Region
Authors: Payer Melissa , Laird Neil F. , Maliawco Richard J. , Hoffman Eric G.
Published: August 2011

The temporal frequency and spatial distributions of fronts and troughs in the Great Lakes region from a 6-yr period (January 2000–December 2005) are presented. Frontal frequencies indicated that cold fronts were the most common, followed by stationary, warm, and occluded fronts, in that order. The variation in the annual frequency of all front types was small throughout the period. Troughs were present more frequently than any front type and exhibited greater variability of annual frequency. An investigation of the relation of fronts and troughs to surface baroclinic zones found that approximately 54% of analyzed fronts were associated with a moderate potential temperature gradient of at least 3.5°C (100 km)−1. Nearly 10% of all fronts were associated with a strong baroclinic zone having a potential temperature gradient of at least 7.0°C (100 km)−1. Moderate or strong baroclinic zones were associated with about 34% of the analyzed troughs in the Great Lakes region and this relationship was further examined for three different trough classifications (i.e., synoptic, subsynoptic, and mesoscale). This study is one of very few to present the climatological variability of surface fronts of all types across a region and the results provide useful insights into the current operational determination of analyzed surface fronts and troughs by quantifying their association with surface baroclinic zones in the Great Lakes region.
Impacts of the High-Resolution Sea Surface Temperature Distribution on Modeled Snowfall Formation over the Yellow Sea during a Cold-Air Outbreak
Authors: Cha Yeong-Min , Lee Hwa-Woon , Lee Soon-Hwan
Published: August 2011

High-resolution sea surface temperature (SST) products and idealized SST distributions were used to simulate snowfall over the Yellow Sea during 30–31 December 2007 using the Weather Research and Forecasting Model (WRF). Large differences were found between the SST distributions in the New Generation Sea Surface Temperature (NGSST) and Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA) datasets near the Yellow Sea coast. Idealized SST datasets were defined to examine the influence of this difference in detail. The SST differences influenced the cloud streets and resultant snowfall formation. In simulations with the idealized SST distributions, convection developed and intensified later when the SST gradient was increased. In addition, the intensity of cloud streets was enhanced along the center of the flow. The simulations using the NGSST dataset showed widely distributed cloud streets and snowfall and heavier snowfall over the western Korean Peninsula, while those using the OSTIA dataset showed a concentrated distribution of cloud streets and snowfall along the center of airflow and more intense snowfall over North Jeolla Province, Korea, than in other regions. Comparing real SST products with observations qualitatively and quantitatively, OSTIA is found to have simulated the distribution and intensity of snowfall better than NGSST.