bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sea‐tide effects on flows in the lower reaches of the Amazon River
Authors: Kosuth Pascal , Callède Jacques , Laraque Alain , Filizola Naziano , Guyot Jean Loup , Seyler Patrick , Fritsch Jean Marie , Guimarães Valdemar 
Published: September 2009

AbstractThe physical influence of sea tides on the lower reaches of the Amazon River can be identified more than 1000 km upstream from the sea. Analysis of upstream tidal wave propagation on the Amazon River contributes to the understanding of the hydrodynamics of the lower reaches and to the quantification of the influence of sea level on sedimentation rates. Continuous over‐the‐year recording of water levels has been undertaken at eight locations along the lower reaches of the Amazon River and flow measurement campaigns have been organized for different river discharge rates (100 000 m3 s−1, 190 000 m3 s−1 and 250 000 m3 s−1) and sea‐tide amplitudes (2–3·5 m). Damping, time‐delay and deformation of the tidal wave signals, depending on water regimes and distances from the sea, have been analyzed. The physical processes of wave propagation and cyclic water storage and release have been investigated both through data analysis and the application of mathematical hydrodynamic models. The impact of tidal pulses on sediment transport to the sea has been assessed. Copyright © 2009 John Wiley & Sons, Ltd.
Maximum flood regionalization in large basins: study case of the Alto São Francisco region—Minas Gerais, Brazil
Authors: Versiani Bruno Rabelo , de Melo Franco Carneiro Rafael , Amaral Iara Righi , Finzi Quintão Cristiane Medina 
Published: September 2009

AbstractThis paper describes a regionalization method, based on the TCEV (two‐component extreme value) distribution function, and its application to annual maximum flood series for the São Francisco River, in Minas Gerais State (Brazil). This statistical model is equivalent to the product of two exponentials, both representing a Poisson process: the first corresponding to the most frequent floods and the second to the rare floods. The theoretical aspects of the model and the regionalization method are briefly presented. The study region is a 50 870 km2 river basin, located in the southeast region of Brazil, characterized by a tropical climate. In applying the technique, two homogeneous regions were identified, dividing the basin into southern and northern parts with respect to the annual maximum floods. To validate the TCEV regionalization model, a stream gauge with a short of maximum floods that was not used in the fitting procedure was selected. The TCEV regionalized model fitted well, showing that the method can be used for prediction across the entire basin. Copyright © 2009 John Wiley & Sons, Ltd.
Hydrologic model calibration using discontinuous data: an example from the upper Blue Nile River Basin of Ethiopia
Authors: Kim Ungtae , Kaluarachchi Jagath J. 
Published: September 2009

AbstractHydrologic models using water balance approaches typically use continuously observed streamflow data for calibration. Many large river basins in developing countries such as the upper Blue Nile River Basin of Ethiopia have discontinuous hydrographs that contain short continuous periods. Therefore, the efficient use of observed hydrographs for calibration of a hydrologic model is important to improve model performance. The goal of this study is to assess how limitations of continuity and duration in data affect hydrologic model calibration. A previously developed water balance model for the upper Blue Nile River basin was calibrated here using continuous and discontinuous (randomly sampled) data of different lengths. The performance of both methods was then compared each other in terms of parameter uncertainty and model efficiency. The results revealed that randomly sampled data require a shorter calibration length than continuous data to reach good model performance, about 36 and 120 months, respectively. This fact implies that discontinuous hydrographs can be useful in calibration. However, the number of high flow months included in the calibration data greatly affects model efficiency. This study suggests that randomly sampled calibration data should include at least 30% of high flow months of sufficient quality. The findings of this study will be essential to develop a hydrologic monitoring strategy for remote basins of the upper Blue Nile River basin and other similar basins where continuous observations are limited. Copyright © 2009 John Wiley & Sons, Ltd.
Tuning the properties of the bacterial membrane with aminoacylated phosphatidylglycerol
Authors: Roy Hervé 
Published: September 2009

AbstractThe bacterial envelope is a semi‐permeable barrier that protects the cell from the hostilities of the environment. To survive the ever‐changing conditions of their surroundings, bacteria need to rapidly adjust the biochemical properties of their cellular envelope. Amino acid (aa) addition to phosphatidylglycerol (PG) of the membrane is one of the mechanisms used by bacteria to lower the net negative charge of their cellular envelope, thereby decreasing its affinity for several antibacterial agents such as the cationic antimicrobial peptides (CAMPs) produced by the innate immune response during host infection. This process requires the activity of an integral membrane protein, called aa‐PG synthase (aaPGS), to transfer the aa of aminoacyl‐tRNA (aa‐tRNA) onto the PG of the membrane. aaPGSs constitute a new family of virulence factors that are found in a wide range of microorganisms. aa‐PGs not only provide resistance to CAMPs but also to other classes of antibacterial agents and to environmental stresses such as those encountered during extreme osmotic or acidic conditions. This review will describe the known biochemical properties of aa‐PGSs, their specificity for aa‐tRNAs and phospholipids, and the growing repertoire of aa used as substrates by these enzymes. Their prevalence in bacteria and the phenotypes and modulations of membrane properties associated with these molecules will be addressed, as well as their regulation as a component of the envelope stress response system in certain bacteria. © 2009 IUBMB IUBMB Life, 61(10): 940–953, 2009
Androgen receptor and caveolin‐1 in prostate cancer
Authors: Bennett Nigel , Hooper John D. , Lee C. Soon , Gobe Glenda C. 
Published: September 2009

AbstractThe androgen receptor (AR) is involved in the development and maintenance of the normal prostate and the development and progression of prostate cancer (PCa). Caveolin‐1 (cav‐1) is an AR co‐regulator. The expression of this integral membrane protein is upregulated in PCa and correlates positively with its development. This review focuses on the likely interactive roles of AR and cav‐1, with particular reference to progression to androgen‐insensitivity in PCa. The classical role of AR is modulation of gene transcription by binding specific DNA sequences called androgen response elements in the promoter regions of target genes. To carry out this role, AR interacts with many co‐regulator proteins which either enhance or repress its activation. Altered expression or misregulated activation of a co‐regulator protein may significantly alter AR activity and the basal transcription rate of androgen responsive genes. Cav‐1 has roles in cell signalling and trafficking, roles that are important in PCa survival, metastasis, and the development of multidrug resistant phenotypes. Although cav‐1 appears to increase AR genomic activity and increase tumor cell survival, there is also mounting evidence that cav‐1 can manipulate rapid, non‐genomic AR signalling at the plasma membrane. By increasing our understanding of cav‐1 as an AR co‐regulator, we may be able to reinstate appropriate transcriptional responses to androgen signalling and minimise misregulated AR activity, thus permitting more effective targeted therapies for PCa. © 2009 IUBMB IUBMB Life, 61(10): 961–970, 2009
Emerging roles of glucocorticoid receptor phosphorylation in modulating glucocorticoid hormone action in health and disease
Authors: Galliher‐Beckley Amy J. , Cidlowski John A. 
Published: September 2009

AbstractGlucocorticoids (GCs) are hormones naturally released when the body perceives stress and function to return homeostatic balance within various tissues. Synthetic GCs are widely prescribed therapeutics for the treatment of numerous inflammatory disorders and cancers. The effects of GCs are mediated by their binding and activation of the GC receptor (GR), a transcription factor that is subject to hormone‐dependent and ‐independent phosphorylation on several serine and threonine residues. The GR is phosphorylated by kinases such as MAPKs, CDKs, and GSK‐3β, and these modifications modulate the transcriptional activity of the GR within cells. Here, we discuss the phosphorylation status of the GR as a mechanism to dictate how cells will ultimately respond to GCs. In doing so, we will review current knowledge about each phosphorylated residue within the GR and their contributions to modulating GC signaling in normal homeostatic physiology and during the progression of disease. © 2009 IUBMB IUBMB Life, 61(10): 979–986, 2009
Models of stochastic choice and decision theories: why both are important for analyzing decisions
Authors: Blavatskyy Pavlo R. , Pogrebna Ganna 
Published: September 2009

AbstractWe select a menu of seven popular decision theories and embed each theory in five models of stochastic choice, including tremble, Fechner and random utility model. We find that the estimated parameters of decision theories differ significantly when theories are combined with different models. Depending on the selected model of stochastic choice we obtain different rankings of decision theories with regard to their goodness of fit to the data. The fit of all analyzed decision theories improves significantly when they are embedded in a Fechner model of heteroscedastic truncated errors or a random utility model. Copyright © 2009 John Wiley & Sons, Ltd.
Estimating time variation in measurement error from data revisions: an application to backcasting and forecasting in dynamic models
Authors: Kapetanios George , Yates Tony 
Published: September 2009

AbstractOver time, economic statistics are refined. This implies that data measuring recent economic events are typically less reliable than older data. Such time variation in measurement error affects optimal forecasts. Measurement error, and its time variation, are of course unobserved. Our contribution is to show how estimates of these can be recovered from the variance of revisions to data using a behavioural model of the statistics agency. We illustrate the gains in forecasting performance from exploiting these estimates using a real‐time dataset on UK aggregate expenditure data. Copyright © 2009 John Wiley & Sons, Ltd.
International evidence on the efficacy of new‐Keynesian models of inflation persistence
Authors: Korenok Oleg , Radchenko Stanislav , Swanson Norman R. 
Published: September 2009

AbstractWe take an agnostic view of the Phillips curve debate, and carry out an empirical investigation of the relative and absolute efficacy of Calvo sticky price (SP), sticky information (SI), and sticky price with indexation models (SPI), with emphasis on their ability to mimic inflationary dynamics. We look at evidence for a group of 13 OECD countries, and consider three alternative measures of inflationary pressure, including the output gap, labor share, and unemployment. We find that the SPI model is preferable to the Calvo SP and the SI models because it captures the type of strong inflationary persistence that has in the past characterized the economies in our sample. However, two caveats to this conclusion are that improvement in performance is driven mostly by lagged inflation and that the SPI model overemphasizes inflationary persistence. There appears to be room for improvement in all models in order to induce them to better ‘track’ inflation persistence. Copyright © 2009 John Wiley & Sons, Ltd.
Toward a practical protocol for human optic nerve DTI with EPI geometric distortion correction
Authors: Techavipoo Udomchai , Okai Annette F. , Lackey John , Shi Jianrong , Dresner Michael A. , Leist Thomas P. , Lai Song 
Published: September 2009

AbstractPurposeTo develop a practical protocol for diffusion tensor imaging (DTI) of the human optic nerve with echo planar imaging (EPI) geometric distortion correction.Materials and MethodsA conventional DTI protocol was modified to acquire images with fat and cerebrospinal fluid (CSF) suppression and field inhomogeneity maps of contiguous coronal slices covering the whole brain. The technique was applied to healthy volunteers and multiple sclerosis patients with and without a history of unilateral optic neuritis. DTI measures and optic nerve tractography before and after geometric distortion correction were compared. Diffusion measures from left and right or from affected and unaffected eyes in different subject cohorts were reported.ResultsThe image geometry after correction closely resembled reference anatomical images. Optic nerve tractography became feasible after distortion correction. The diffusion measures from the healthy volunteers were in good agreement with the literature. Statistically significant differences were found in the fractional anisotropy and orthogonal eigenvalues between affected and unaffected eyes in optic neuritis patients with poor recovery. The diffusion measures before and after geometric distortion correction were not significantly different. For cohorts without optic neuritis, the difference between diffusion measures from left and right eyes was not statistically significant.ConclusionThe proposed technique could provide a practical DTI protocol to study the human optic nerve. J. Magn. Reson. Imaging 2009;30:699–707. © 2009 Wiley‐Liss, Inc.
High resolution fast T1 mapping technique for dGEMRIC
Authors: Sur Samir , Mamisch Tallal Charles , Hughes Timothy , Kim Young‐Jo 
Published: September 2009

AbstractPurposeTo determine the feasibility of using a high resolution isotropic three‐dimensional (3D) fast T1 mapping sequence for delayed gadolinium‐enhanced MRI of cartilage (dGEMRIC) to assess osteoarthritis in the hip.Materials and MethodsT1 maps of the hip were acquired using both low and high resolution techniques following the administration of 0.2 mmol/kg Gd‐DTPA2‐ in 35 patients. Both T1 maps were generated from two separate spoiled GRE images. The high resolution T1 map was reconstructed in the anatomically equivalent plane as the low resolution map. T1 values from the equivalent anatomic regions containing femoral and acetabular cartilages were measured on the low and high resolution maps and compared using regression analysis.ResultsIn vivo T1 measurements showed a statistically significant correlation between the low and high resolution acquisitions at 1.5 Tesla (R2 = 0.958, P < 0.001). These results demonstrate the feasibility of using a fast two‐angle T1 mapping (F2T1) sequence with isotropic spatial resolution (0.8 × 0.8 × 0.8 mm) for quantitative assessment of biochemical status in articular cartilage of the hip.ConclusionThe high resolution 3D F2T1 sequence provides accurate T1 measurements in femoral and acetabular cartilages of the hip, which enables the biochemical assessment of articular cartilage in any plane through the joint. It is a powerful tool for researchers and clinicians to acquire high resolution data in a reasonable scan time (< 30 min). J. Magn. Reson. Imaging 2009;30:896–900. © 2009 Wiley‐Liss, Inc.
Left ventricular infarct size, peri‐infarct zone, and papillary scar measurements: A comparison of high‐resolution 3D and conventional 2D late gadolinium enhancement cardiac MR
Authors: Peters Dana C. , Appelbaum Evan A. , Nezafat Reza , Dokhan Basem , Han Yuchi , Kissinger Kraig V. , Goddu Beth , Manning Warren J. 
Published: September 2009

AbstractPurposeTo compare higher spatial resolution 3D late gadolinium enhancement (LGE) cardiovascular magnetic resonance (Cardiac MR) with 2D LGE in patients with prior myocardial infarction.Materials and MethodsFourteen patients were studied using high spatial resolution 3D LGE (1.3 × 1.3 × 5.0 mm3) and conventional 2D LGE (2 × 2 × 8 mm3) scans. The signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR) were measured. Total infarct volume, peri‐infarct volume measured in a limited slab, and papillary muscle scar volume were compared using Bland–Altman analysis. Image quality was graded.Results3D LGE had higher scar SNR (P < 0.001), higher myocardial SNR (P = 0.001), higher papillary scar‐blood CNR (P = 0.01), and greater sharpness (P = 0.01). The scar volumes agreed (14.5 ± 8.2 for 2D, vs. 13.2 ± 8.8 for 3D), with bias ± 2 standard deviations (SDs) of 0.5 ± 6.8 mL, P = 0.59 R = 0.91. The peri‐infarct volumes correlated but less strongly than scar (P = 0.40, R = 0.77). For patients with more heterogeneous scar, larger peri‐infarct volumes were measured by 3D (1.9 ± 1.1 mL for 2D vs. 2.4 ± 1.6 mL for 3D, P = 0.15, in the matched region). Papillary scar, present in 6/14 (42%) patients, was more confidently identified on 3D LGE.ConclusionHigher spatial resolution 3D LGE provides sharper images and higher SNR, but less myocardial nulling. Scar volumes agree well, with peri‐infarct volumes correlating less well. 3D LGE may be superior in visualization of papillary muscle scar. J. Magn. Reson. Imaging 2009;30:794–800. © 2009 Wiley‐Liss, Inc.
Comprehensive adenosine stress perfusion MRI defines the etiology of chest pain in the emergency room: Comparison with nuclear stress test
Authors: Vogel‐Claussen Jens , Skrok Jan , Dombroski David , Shea Steven M. , Shapiro Edward P. , Bohlman Mark , Lorenz Christine H. , Lima Joao A.C. , Bluemke David A. 
Published: September 2009

AbstractPurposeTo compare standard of care nuclear SPECT imaging with cardiac magnetic resonance imaging (MRI) for emergency room (ER) patients with chest pain and intermediate probability for coronary artery disease.Materials and MethodsThirty‐one patients with chest pain, negative electrocardiogram (ECG), and negative cardiac enzymes who underwent cardiac single photon emission tomography (SPECT) within 24 h of ER admission were enrolled. Patients underwent a comprehensive cardiac MRI exam including gated cine imaging, adenosine stress and rest perfusion imaging and delayed enhancement imaging. Patients were followed for 14 ± 4.7 months.ResultsOf 27 patients, 8 (30%) showed subendocardial hypoperfusion on MRI that was not detected on SPECT. These patients had a higher rate of diabetes (P = 0.01) and hypertension (P = 0.01) and a lower global myocardial perfusion reserve (P = 0.01) compared with patients with a normal cardiac MRI (n = 10). Patients with subendocardial hypoperfusion had more risk factors for cardiovascular disease (mean 4.4) compared with patients with a normal MRI (mean 2.5; P = 0.005). During the follow‐up period, patients with subendocardial hypoperfusion on stress MRI were more likely to return to the ER with chest pain compared with patients who had a normal cardiac MRI (P = 0.02). Four patients did not finish the MR exam due to claustrophobia.ConclusionIn patients with chest pain, diabetes and hypertension, cardiac stress perfusion MRI identified diffuse subendocardial hypoperfusion defects in the ER setting not seen on cardiac SPECT, which is suspected to reflect microvascular disease. J. Magn. Reson. Imaging 2009;30:753–762. © 2009 Wiley‐Liss, Inc.
Gadolinium pharmacokinetics of chronic myocardial infarcts: Implications for late gadolinium‐enhanced infarct imaging
Authors: Goldfarb James W. , Arnold Sheeba , Roth Marguerite 
Published: September 2009

AbstractPurposeTo monitor gadolinium pharmacokinetics in the hearts of patients with chronic myocardial infarcts and to determine the variability of contrast agent concentrations and accuracy of infarct detection over an hour time period.Materials and MethodsTwenty‐five patients with chronic myocardial infarcts were examined. T1 measurements were performed every 2 minutes using an inversion recovery CINE balanced steady‐state free precession technique. Paired differences in T1 values over time for the discrimination between the left ventricular (LV) bloodpool, viable, and infarct myocardium were statistically evaluated. The average change per 1, 5, and 10 minutes of the inversion time parameter for optimal nulling of viable myocardium was calculated. Receiver operator characteristic (ROC) curve analysis was performed to compare the performance of late gadolinium‐enhanced infarct imaging at increasing delays after contrast agent administration.ResultsSignificantly different T1 values were reached after 10 minutes between the LV bloodpool, infarcted, and viable myocardium. The T1 difference between myocardial infarcts and the LV bloodpool increased over time, while the difference between viable myocardium and the LV bloodpool decreased. ROC curve analysis showed a decrease in performance of a fixed T1 value to discriminate between the LV bloodpool and viable myocardium over time, while there was a marked increase in the discrimination between the LV bloodpool and infarcted myocardium.ConclusionThe ability to discriminate between infarcted myocardium and the LV bloodpool improves with an increasing delay after contrast agent administration while discrimination between viable myocardium and the LV bloodpool decreases. J. Magn. Reson. Imaging 2009;30:763–770. © 2009 Wiley‐Liss, Inc.
Multicontrast late gadolinium enhancement imaging enables viability and wall motion assessment in a single acquisition with reduced scan times
Authors: Connelly Kim A. , Detsky Jay S. , Graham John J. , Paul Gideon , Vijayaragavan Ram , Dick Alexander J. , Wright Graham A. 
Published: September 2009

AbstractPurposeTo determine the accuracy of multicontrast late enhancement imaging (MCLE) in the assessment of myocardial viability and wall motion compared to the conventional wall motion and viability cardiac magnetic resonance imaging (MRI) pulse sequences.Materials and MethodsForty‐one patients with suspected myocardial infarction were studied. Patients underwent assessment of cardiac function with cine steady‐state free‐precession (SSFP), followed by late gadolinium enhancement (LGE) imaging using inversion recovery gradient echo scanning (IR‐GRE) sequence and MCLE. MCLE was compared to cine SSFP in the assessment of wall motion, ejection fraction (EF), left ventricular (LV) mass, LV end‐diastolic volume (EDV), and to IR‐GRE for measuring infarct size.ResultsMCLE, IR‐GRE, and SSFP imaging demonstrated excellent agreement in the assessment of EF, LV infarct size, and LV mass (r > 0.95, P < 0.001 for all measures), as well as in the assessment of wall motion (κ statistic 0.75).ConclusionMCLE provided coregistered images for the assessment of viability and wall motion without loss of accuracy in the assessment of quantitative cardiac parameters. MCLE provides accurate quantitative cardiac assessment with reduced scan times compared to the conventional sequences and thus may be used as an alternative to conventional cine SSFP and IR‐GRE imaging. J. Magn. Reson. Imaging 2009;30:771–777. © 2009 Wiley‐Liss, Inc.