bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using redundancy analysis to improve dynamical seasonal mean 500 hPa geopotential forecasts
Authors: Wang Xiaolan L. , Zwiers Francis W. 
Published: September 2002

AbstractIn this study, we evaluate and compare 500 hPa geopotential height hindcast skill in two large dynamical hindcast experiments performed with the Canadian Climate Centre second generation general circulation model (GCM). In one hindcast experiment, seasonal hindcasts are made from lagged initial conditions observed at the beginning of each season. The sea‐surface temperatures (SSTs) required by the model during each forecast period are forecast by persisting the SST anomalies observed during the month just prior to the forecast period. The second hindcast experiment consists of an ensemble of simulations in which continuously evolving observed SSTs are specified at the model's lower boundary. These hindcasts do not benefit from re‐specification of the initial state at the beginning of each season, but they do enjoy the benefit of ‘perfect’ SST forecasts. We also demonstrate the use of a regression technique, called redundancy analysis (RA), for statistically improving the skill of both types of dynamical hindcast. The results indicate that specification of the initial state at the beginning of each season adds skill to the seasonal hindcasts, even though SSTs at the lower boundary are imperfectly specified. We also find that the model can predict the mean state of the North Atlantic Oscillation (NAO) with some skill in boreal winter and spring when the initial state is specified at the beginning of each season. The results also indicate that statistical post‐processing with the RA technique improves the (cross‐validated) skill of both types of dynamical hindcast. Copyright © 2001 Royal Meteorological Society
Downscaling temperature and precipitation: a comparison of regression‐based methods and artificial neural networks
Authors: Schoof J.T. , Pryor S.C. 
Published: September 2002

AbstractA comparison of two statistical downscaling methods for daily maximum and minimum surface air temperature, total daily precipitation and total monthly precipitation at Indianapolis, IN, USA, is presented. The analysis is conducted for two seasons, the growing season and the non‐growing season, defined based on variability of surface air temperature. The predictors used in the downscaling are indices of the synoptic scale circulation derived from rotated principal components analysis (PCA) and cluster analysis of variables extracted from an 18‐year record from seven rawinsonde stations in the Midwest region of the United States. PCA yielded seven significant components for the growing season and five significant components for the non‐growing season. These PCs explained 86% and 83% of the original rawinsonde data for the growing and non‐growing seasons, respectively. Cluster analysis of the PC scores using the average linkage method resulted in eight growing season synoptic types and twelve non‐growing synoptic types. The downscaling of temperature and precipitation is conducted using PC scores and cluster frequencies in regression models and artificial neural networks (ANNs).Regression models and ANNs yielded similar results, but the data for each regression model violated at least one of the assumptions of regression analysis. As expected, the accuracy of the downscaling models for temperature was superior to that for precipitation. The accuracy of all temperature models was improved by adding an autoregressive term, which also changed the relative importance of the dominant anomaly patterns as manifest in the PC scores. Application of the transfer functions to model daily maximum and minimum temperature data from an independent time series resulted in correlation coefficients of 0.34–0.89. In accord with previous studies, the precipitation models exhibited lesser predictive capabilities. The correlation coefficient for predicted versus observed daily precipitation totals was less than 0.5 for both seasons, while that for monthly total precipitation was below 0.65. The downscaling techniques are discussed in terms of model performance, comparison of techniques and possible model improvements. Copyright © 2001 Royal Meteorological Society
Changes in total precipitation, rainy days and extreme events in northeastern Italy
Authors: Brunetti Michele , Maugeri Maurizio , Nanni Teresa 
Published: September 2002

AbstractA new daily precipitation dataset, for the period 1920–1998, comprising seven stations located in the northeastern Italy is presented.Seasonal and annual precipitation and number of rainy days have been analysed and a study aimed at investigating precipitation intensity and extreme events has been performed. Precipitation intensity has been analysed through studying both the mean precipitation amount per wet day and dividing precipitation into heavy and non‐heavy classes. In addition, the return period of the extreme events has been calculated for 30‐year running windows and its variations have been examined.The results show a negative trend in the number of wet days associated with an increase in the contribution of heavy rainfall events to total precipitation. This is in agreement with a reduction in return period for extreme events since 1920. Copyright © 2001 Royal Meteorological Society
Dissociation and rate of proton transfer of HXO3 (X = Cl, Br) in aqueous solution determined by Raman spectroscopy
Authors: Alves Wagner A. , Téllez S Claudio A. , Sala Oswaldo , Santos Paulo S. , Faria Roberto B. 
Published: September 2002

AbstractRaman spectra of aqueous halate and oxyacids HXO3 (X = Cl,Br) solutions were obtained. Integrated Raman intensity measurements of the 804 and 933 cm−1 bands of HBrO3 and HClO3 in aqueous solutions, respectively, allowed the determination of the degree of dissociation of these acids in the molarity range studied. The results show that these acids are almost completely dissociated until the maximum concentration studied. In addition, we observed that bromic and chloric acid solutions with concentrations ≥ 3.2 and 2.5 mol L−1, respectively, decompose to bromine and chlorine at room temperature. The trend of the Raman specific intensities of the halate ions (BrO3− > ClO3−) bands in aqueous solutions is discussed and compared with that observed by other workers who considered the contributions of the isotropic and anisotropic components of the polarizability tensor. Measurements of the Raman line broadening of the same bands gave values of 2.6 × 1011 L mol−1 s−1 for the second‐order rate constant of the reaction between H+ and BrO3− and 3.4 × 1011 L mol−1 s−1 for the reaction between H+ and CIO3−. Copyright © 2001 John Wiley & Sons, Ltd.
Phytate content and phytate degradation by endogenous phytase in pea (Pisum sativum)
Authors: Fredrikson Mattias , Alminger Marie Larsson , Carlsson Nils‐Gunnar , Sandberg Ann‐Sofie 
Published: September 2002

AbstractIn order to rapidly reduce the content of inositol tri–hexaphosphates in pea flour by action of the endogenous phytase, raw materials as well as incubation conditions have been evaluated. The phytate (inositol hexaphosphate) content was analysed in 27 pea varieties; the influence of storage time and the difference in phytate content between the germ and the cotyledon were determined. Furthermore, degradation of inositol phosphates by the endogenous phytase enzyme was studied in pea flour, germ and cotyledon. To find the maximum phytate degradation, the effects of temperature and pH during pea flour incubation were investigated. The most efficient phytate degradation in pea flour incubation was achieved at pH 7.5 and 45 °C. At this condition an almost complete degradation of phytate and a 66% reduction in the sum of inositol hexa‐, penta‐, tetra‐ and triphosphates were reached in 10 h. The storage time of pea seeds or removal of the germ did not have a major effect on the phytate content. Since several inositol pentaphosphate isomers were produced during phytate degradation, it can be concluded that peas contain several phytate‐degrading enzymes, or one phytate‐degrading enzyme with unspecific initial hydrolysation pattern.© 2001 Society of Chemical Industry.
Ethnography: a research method in practice
Authors: Palmer Catherine 
Published: September 2002

AbstractThis article discusses the ethnographic methods employed for a doctoral study focusing upon heritage tourism and English national identity. It explains the fundamental principles behind the research and how the field work was conducted. In addition, it examines the issues of practicality which emerged during the research process and discusses how these were resolved. The article concludes by highlighting the importance of ethnography as a tool for understanding and interpreting visitor behaviour. Copyright © 2001 John Wiley & Sons, Ltd.
Mathematical formulas for ester hydrolysis and formation
Authors: Hunter L. W. 
Published: September 2002

AbstractMathematical formulas are developed to describe the progress of ester hydrolysis reactions and the reverse reactions of ester formation, in aqueous solution. Included is a formula for the time to achieve a given degree of reaction. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 277–280, 2001
Direct kinetics study of the temperature dependence of the CH2O branching channel for the CH3O2 + HO2 reaction
Authors: Elrod Matthew J. , Ranschaert Dana L. , Schneider Nicholas J. 
Published: September 2002

AbstractA direct kinetics study of the temperature dependence of the CH2O branching channel for the CH3O2 + HO2 reaction has been performed using the turbulent flow technique with high‐pressure chemical ionization mass spectrometry for the detection of reactants and products. The temperature dependence of the CH2O‐producing channel rate constant was investigated between 298 and 218 K at a pressure of 100 Torr, and the data were fitted to the following Arrhenius expression: 1.6 × 10−15 × exp[(1730 ± 130)/T] cm3 molecule−1 s−1. Using the Arrhenius expression for the overall rate of the CH3O2 + HO2 reaction and this result, the 298 K branching ratio for the CH2O producing channel is measured to be 0.11, and the branching ratio is calculated to increase to a value of 0.31 at 218 K, the lowest temperature accessed in this study. The results are compared to the analogous CH3O2 + CH3O2 reaction and the potential atmospheric ramifications of significant CH2O production from the CH3O2 + HO2 reaction are discussed. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 363–376, 2001
The N(4S) + N2O(X̃1∑) reaction
Authors: Fernandez Abel , Fontijn Arthur 
Published: September 2002

AbstractThe title reaction, which is spin‐forbidden for N2(X1∑) + NO(X2Π) production, has been studied from 960 to 1130 K in a high‐temperature photochemistry reactor. No reaction could be observed, indicating k < 1 × 10−15 cm3 molecule−1 s−1. It is concluded that there is no significant contribution from the spin‐allowed exothermic path leading to N2(X1∑) + NO(a4Π). © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 387–389, 2001
Inhibitory effect of silibinin on ligand binding to erbB1 and associated mitogenic signaling, growth, and DNA synthesis in advanced human prostate carcinoma cells
Authors: Sharma Yogesh , Agarwal Chapla , Singh Ashvani K. , Agarwal Rajesh 
Published: September 2002

AbstractWe recently showed the inhibitory effect of a flavonoid antioxidant, silymarin, on erbB1‐Shc activation in prostate cancer (PCA) DU145 cells. In the present study, we performed more detailed mechanistic and molecular modeling studies with pure silibinin to assess and define its effect on membrane signaling related to erbB1 activation in human PCA LNCaP and DU145 cells. Studies also were performed to establish the biologic responses toward extracellular signal‐regulated protein kinase 1/2 (ERK1/2) activation, cell growth, and DNA synthesis. Treatment of serum‐starved cells with various doses of silibinin for 2 h followed by 125I‐epidermal growth factor (EGF) showed 30–75% inhibition in ligand binding and 55–95% inhibition in its internalization in LNCaP cells and 20–64% and 12–27% inhibition in these two events in DU145 cells. Time‐response studies showed similar effects. In further studies, treatment of serum‐starved cultures with silibinin followed by EGF showed strong inhibitory effects on membrane and cytoplasmic signaling molecules. In the case of erbB1 activation, silibinin showed a 58–75% decrease in LNCaP and a 40–100% decrease in DU145 cells at 50, 75, and 100‐μg/mL doses. Inhibitory effects of silibinin also were evident on ERK1/2 activation (20–80% inhibition) in both cell lines. Treatment of serum‐starved cultures with silibinin resulted in 20–40% and 30–55% inhibition of LNCaP and DU145 cell growth, respectively, at similar doses after 1–3 d of treatment, and 10–50% cell death in both cell lines. Under 10% serum conditions, identical silibinin treatments resulted in 20–65% inhibition of cell growth in LNCaP and DU145 cells but did not cause any cell death. Similar doses of silibinin treatments for 24 h also resulted in 25–60%, 35–40%, and 36–50% inhibition of DNA synthesis when cells were cultured in 10% serum, totally serum starved, and serum starved plus stimulated with EGF, respectively. Molecular modeling of silibinin showed that it is a highly lipophilic compound, suggesting that it interacts with lipid‐rich plasma membrane, including binding with erbB1, thereby competing with the EGF‐erbB1 interaction. Because the ligand‐erbB1 autocrine‐loop is causally involved in advanced and androgen‐independent PCA, the observed effects of silibinin and its strong lipophilic nature could be useful in developing this agent for the prevention and therapy of PCA. © 2001 Wiley‐Liss, Inc.
Functional assessment of peripheral nerve recovery in the rat: Gait kinematics
Authors: Varejão Artur S.P. , Cabrita António M. , Patrício João A. , Bulas‐Cruz José , Gabriel Ronaldo C. , Melo‐Pinto Pedro , Couto Pedro A. , Meek Marcel F. 
Published: September 2002

AbstractComputerized rat gait analysis has become an invaluable technique of functional evaluation for some peripheral nerve investigators, comparing the normal and the pathological kinematic data. Appropriate selection of the methods to evaluate the functional outcome should be sensitive enough to moderate changes. By combining kinematic data and traditional methods in regeneration studies, it is possible to achieve better documentation of functional changes with the passage of time. A review of the three commonly kinematic parameters used in nerve regeneration studies, such as the calculation of sciatic function index, stance factor, and ankle angle, will provide the reader with detailed information about this accurate and consistent means of evaluating peripheral nerve function after nerve injury and repair. This study aims to review the different methods and potentialities of the rat gait kinematics as a noninvasive evaluation during regeneration, allowing for measurement of the rate of functional recovery in experimental studies. © 2001 Wiley‐Liss, Inc. MICROSURGERY 21:383–388 2001
Global solution curves for semilinear systems
Authors: Korman Philip 
Published: September 2002

AbstractWe study semilinear elliptic systems in two different directions. In the first one we give a simple constructive proof existence of solutions for a class of sublinear systems. Our main results are in the second direction, where we use bifurcation theory to study global solution curves. Crucial to our analysis is proving positivity properties of the corresponding linearized systems. Copyright © 2002 John Wiley & Sons, Ltd.
Bound for resolvent of second order elliptic operator in low spectral stripe
Authors: Łada Andrzej , Sidz Leszek 
Published: September 2002

AbstractMourre method of commutators is used to get low energy resolvent bound for an abstract operatorin a Hilbert space and for a second order variable coefficient elliptic operator in Rd, d⩾3. Copyright © 2002 John Wiley & Sons, Ltd.
NMR applications for solid‐phase synthesis: Part I. Suppression of residual polymer signals in 1D 1H NMR spectroscopy of polymer‐supported species
Authors: Ditty Michael J. T. , Hunter Howard N. , Mainville Rachel M. E. , Power William P. 
Published: September 2002

AbstractA simple and readily implemented technique for suppression of polymer signals in 1H 1D NMR spectroscopy of samples from solid‐phase synthetic methods is described. Based on the 2D TOCSY experiment, and combined with routine magic angle spinning, this sequence can be readily adapted from standard pulse programs and used in a robust way for a range of samples attached to Wang resin. Signal intensities of the attached species retain their quantitative nature, permitting the standard organic spectroscopic analyses to be performed. Copyright © 2001 John Wiley & Sons, Ltd.
α‐, β‐, γ‐catenin, and p120CTN expression during the terminal differentiation and fusion of human mononucleate cytotrophoblasts in vitro and in vivo
Authors: Getsios Spiro , Chen George T.C. , MacCalman Colin D. 
Published: September 2002

AbstractThe cadherins play key roles in the formation and organization of the mammalian placenta by mediating cellular interactions and the terminal differentiation of trophoblastic cells. Although cadherin function is regulated by the cytoplasmic proteins, known as the catenins, the identity and expression pattern(s) of the catenins present in the trophoblastic cells of the human placenta have not been characterized. In these studies, we have determined that α‐, β‐, γ‐catenin, and p120ctn expression levels are high in villous cytotrophoblasts isolated from the human term placenta but decline as these cells undergo aggregation and fusion to form syncytium with time in culture. In contrast, the expression levels of these four catenin subtypes remained constant in non‐fusing JEG‐3 choriocarcinoma cells at all of the time points examined in these studies. α‐, β‐, γ‐catenin, and p120ctn expression was further immunolocalized to the mononucleate cells present in these two trophoblastic cell cultures. Similarly, intense immunostaining for all four catenins was detected in the mononucleate villous cytotrophoblasts of the human first trimester placenta. Collectively, these observations demonstrate that the expression levels of α‐, β‐, γ‐catenin, and p120ctn are tightly regulated during the formation of multinucleated syncytium in vitro and in vivo. Mol. Reprod. Dev. 59:168–177, 2001. © 2001 Wiley‐Liss, Inc.
Spherical navigator echoes for full 3D rigid body motion measurement in MRI
Authors: Welch Edward Brian , Manduca Armando , Grimm Roger C. , Ward Heidi A. , Jack Jr. Clifford R. 
Published: September 2002

AbstractWe developed a 3D spherical navigator (SNAV) echo technique that can measure rigid body motion in all six degrees of freedom simultaneously by sampling a spherical shell in k‐space. 3D rotations of an imaged object simply rotate the data on this shell and can be detected by registration of k‐space magnitude values. 3D translations add phase shifts to the data on the shell and can be detected with a weighted least‐squares fit to the phase differences at corresponding points. MRI pulse sequences were developed to study k‐space sampling strategies on such a shell. Data collected with a computer‐controlled motion phantom with known rotational and translational motions were used to evaluate the technique. The accuracy and precision of the technique depend on the sampling density. Roughly 2000 sample points were necessary for accurate detection to within the error limits of the motion phantom when using a prototype time‐intensive sampling method. This number of samples can be captured in an approximately 27‐ms double excitation SNAV pulse sequence with a 3D helical spiral trajectory. Preliminary results with the helical SNAV are encouraging and indicate that accurate motion measurement suitable for retrospective or prospective correction should be feasible with SNAV echoes. Magn Reson Med 47:32–41, 2002. © 2002 Wiley‐Liss, Inc.
Assessment of a single‐acquisition imaging sequence for oxygen‐sensitive 3He‐MRI
Authors: Deninger A.J. , Eberle B. , Bermuth J. , Escat B. , Markstaller K. , Schmiedeskamp J. , Schreiber W.G. , Surkau R. , Otten E. , Kauczor H.‐U. 
Published: September 2002

AbstractMRI of the lungs using hyperpolarized helium‐3 (3He) allows the determination of intrapulmonary oxygen partial pressures (pO2). The need to separate competing processes of signal loss has hitherto required two different imaging series during two different breathing maneuvers. In this work, a new imaging strategy to measure pO2 by a single series of consecutive scans is presented. The feasibility of the method is demonstrated in three healthy human volunteers. Maps and histograms of intrapulmonary pO2 are calculated. Changes in the oxygen concentration of the inhaled gas mixture are well reproduced in the histograms. Monte Carlo (MC) simulations of the temporal evolution of 3He hyperpolarization within the lungs were performed to evaluate the accuracy of this measurement technique, and its limitations. Magn Reson Med 47:105–114, 2002. © 2002 Wiley‐Liss, Inc.
Online motion correction for diffusion‐weighted imaging using navigator echoes: Application to RARE imaging without sensitivity loss
Authors: Norris David G. , Driesel Wolfgang 
Published: September 2002

AbstractThis article describes the first application of true online motion correction to diffusion‐weighted RARE imaging. Two orthogonal navigator echoes were acquired and zeroth and first‐order phase corrections applied in less than 8 ms between a diffusion‐weighted magnetization preparation and data acquisition using the RARE sequence. The zeroth‐order phase correction was realized by pulsing the system's B0‐coil: the first‐order error corrected with appropriate magnetic field gradient pulses. Online correction ensured that no irreversible signal loss could occur in the imaging experiment. Diffusion‐weighted images of the brain were obtained from healthy volunteers. EGG‐triggered acquisition was applied at 400 ms after the R‐wave. Data were acquired on a matrix of 256 × 256 with a RARE factor of 16 and a b‐value of 804 smm−2. The images obtained with online motion correction showed a remarkably high image quality, while those acquired without motion correction were severely degraded by artifacts. Magn Reson Med 45:729–733, 2001. © 2001 Wiley‐Liss, Inc.