bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterizing degradation products of peptides containing N‐terminal Cys residues by (off‐line high‐performance liquid chromatography)/matrix‐assisted laser desorption/ionization quadrupole time‐of‐flight measurements
Authors: Krokhin Oleg V. , Ens Werner , Standing Kenneth G.
Published: November 2003

A transformation analogous to the well‐known conversion of an N‐terminal glutamine residue to pyroglutamic acid is the cyclization of an N‐terminal carboxamidomethylated cysteine residue (the normal product of alkylation with iodoacetamide). This yields 5‐oxothiomorpholine‐3‐carboxylic acid, with the same 17 Da mass loss observed in the Gln reaction. Nineteen tryptic peptides with Cys at the N‐terminal were identified for this study, and compared with eight with N‐terminal Gln. When examined by MALDI‐QqTOF and (off‐line HPLC)/MALDI‐QqTOF measurements, these were all found to undergo the cyclization reactions. The average degree of degradation during overnight digestion was found to be ∼51 and ∼34% for Cys and Gln, respectively; more detailed information on the time course of the reactions was obtained for the peptides CCTESLVNR and QYYTVFDR. Taking this modification into account while sequencing is likely to increase the probability of protein identification by peptide mass fingerprinting, especially for cysteine‐rich proteins. Copyright © 2003 John Wiley & Sons, Ltd.
A high‐performance matrix‐assisted laser desorption/ionization orthogonal time‐of‐flight mass spectrometer with collisional cooling
Authors: Loboda A. V. , Ackloo S. , Chernushevich I. V.
Published: November 2003

A high‐performance orthogonal time‐of‐flight (TOF) mass spectrometer was developed specifically for use in combination with a matrix‐assisted laser desorption/ionization (MALDI) source. The MALDI source features an ionization region containing a buffer gas with variable pressure. The source is interfaced to the TOF section via a collisional focusing ion guide. The pressure in the source influences the rate of cooling and allows control of ion fragmentation. The instrument provides uniform resolution up to 18 000 FWHM (full width at half maximun). Mass accuracy routinely achieved with a single‐point internal recalibration is below 2 ppm for protein digest samples. The instrument is also capable of recording spectra of samples containing compounds with a broad range of masses while using one set of experimental conditions and without compromising resolution or mass accuracy. Copyright © 2003 John Wiley & Sons, Ltd.
Metabolite profiling in rat urine by liquid chromatography/electrospray ion trap mass spectrometry. Application to the study of heavy metal toxicity
Authors: Lafaye Alexandra , Junot Christophe , Gall Béatrice Ramounet‐Le , Fritsch Paul , Tabet Jean‐Claude , Ezan Eric
Published: November 2003

This work reports the use of reverse‐phase liquid chromatography coupled to electrospray ion trap (QIT) mass spectrometry for the analysis of the metabolome in rat urine. An injection of 20 μL of urine into the chromatographic system is followed by a slow gradient elution and mass spectrometric detection in the scanning mode from m/z 100–1000 in both positive and negative modes. Over a time scale of 90 min, 30 and 20 resolved peaks were observed in the positive and the negative modes, respectively, corresponding to the presence of a few hundred m/z ratios. By using a QIT analyzer, data‐dependent tandem mass spectrometry of selected m/z ratios identified several compounds in rat urine and characterized various chemical families, including carboxylic acids, amines, sulfated compounds, glucuronides and glycosides, by the observation of characteristic fragment ions or neutral losses. The method has been applied to the investigation of the chronic toxicity of heavy metals in rat urine. A few tens of m/z ratios, differing in intensity more than threefold from control values, were observed in both positive and negative modes. The time variations for some selected ions suggest that LC/ESI‐MS could allow selective characterization of biomarkers in response to specific toxic compounds. Copyright © 2003 John Wiley & Sons, Ltd.
Study on Preparation and Thickening Efficiency of an Inverse Emulsion of Anionic Starch‐graft‐Polyacrylamide
Authors: Lu Shaojie , Yao Kangde , Lin Songbai , Cao Deyong , Chen Yiping
Published: November 2003

A series of graft copolymers of starch with polyacrylamide was made by using a K2S2O8 initiation system in inverse emulsion. The corresponding anionic graft copolymers, which have a different hydrolysis degree, are prepared by alkaline hydrolysis of the uncharged graft copolymers. Adequate hydrolytic conditions including type and amount of hydrolyzing agent, temperature, and time were studied. These graft copolymers have been tested for their temperature sensitivity, salt tolerance and shear stability, and a comparison has been made with ungrafted polyacrylamide (PAM). Experiments showed that a high hydrolysis degree can be obtained in a shorter time when NaOH and Na2CO3 were used together as hydrolyzing agents, and the highest solution viscosity was observed when the hydrolysis degree of the graft copolymers was approximately 30%, . In addition, the shear stability, temperature sensitivity and salt tolerance in the graft copolymers were also investigated.
Gibt es eine Stufenspezifität der Änderungsstrategien bei sportlicher Aktivität?
Authors: Maier Angelika , Basler Heinz-Dieter
Published: November 2003

Zusammenfassung. Im Kontext des transtheoretischen Motivationsmodells (TTM) wird angenommen, dass das Voranschreiten von einer Motivationsstufe zur nächsten in spezifischer Weise durch den Einsatz von Motivierungsstrategien unterstützt werden kann. Aufgrund der Erfahrungen mit der Raucherentwöhnung wird auch für die sportliche Aktivität postuliert, dass in frühen Stufen der Verhaltensänderung primär kognitiv-affektive und in späteren Stufen behaviorale Strategien für die Förderung der Motivation von Bedeutung sind. In einer Querschnittsstudie wird dieses Postulat anhand einer Stichprobe von 251 Behördenangestellten untersucht. Die Ergebnisse zeigen, dass sich in bezug auf kognitiv-affektive Strategien die formulierten Erwartungen weitgehend bestätigen lassen, dass aber in Übereinstimmung mit dem Ergebnis einer vorherigen Meta-Analyse behaviorale Strategien in nachfolgenden Stufen jeweils stärker ausgeprägt sind als in vorhergehenden. Weitere Analysen machen deutlich, dass in den Handlungsstufen behaviorale Strategien häufiger eingesetzt werden als kognitive Strategien; in den Vor-Handlungsstufen hingegen unterscheiden sich beide Strategietypen nicht in der Häufigkeit des Einsatzes. Somit werden die aus dem TTM abgeleiteten Erwartungen nur zum Teil bestätigt.
Der Einfluss sozialer Unterstützung auf die prä- und postoperative Anpassung chirurgischer Patienten
Authors: Krohne Heinz W. , El-Giamal Muna , Volz Christine
Published: November 2003

Zusammenfassung. Soziale Unterstützung mit den beiden zentralen Dimensionen der emotionalen und informationellen Unterstützung ist ein wichtiger Prädiktor der perioperativen Anpassung chirurgischer Patienten. Der Fragebogen zur “Emotionalen und Informationellen Sozialen Unterstützung bei Operationen“ (EISOP-R) misst diese Unterstützung auf vier Dimensionen: (1) Emotionale und informationelle Unterstützung durch Fachleute, (2) emotionale Unterstützung aus dem sozialen Netz, (3) informationelle Unterstützung aus dem sozialen Netz sowie (4) Zufriedenheit mit der erhaltenen sozialen Unterstützung. Diese Dimensionen standen in signifikanter Beziehung zu Variablen der perioperativen Anpassung. Emotionale Unterstützung aus dem sozialen Netz sowie Unterstützung durch Fachleute hatten einen günstigen Effekt auf die perioperative Belastung, während informationelle Unterstützung, besonders in der präoperativen Phase, eher belastungssteigernd wirkte. Diese Zusammenhänge fielen bei Frauen deutlicher aus als bei Männern.
Multiples Gesundheitsverhalten und Vulnerabilität im Geschlechtervergleich
Authors: Wiesmann Ulrich , Timm André , Hannich Hans-Joachim
Published: November 2003

Zusammenfassung. Mit dem neu entwickelten Fragebogen zum Multiplen Gesundheitsverhalten (MGV-39) wurde das Spektrum habituellen gesundheitsbezogenen Verhaltens einer studentischen Stichprobe erfasst. Die erhobenen 39 Verhaltensbereiche wiesen eine gute interne Konsistenz auf, was die Bildung eines Summenscores (MGV) erlaubte. In einer Hauptkomponentenanalyse ließen sich die 39 Verhaltenskategorien auf sechs Dimensionen reduzieren: Aktive Lebensgestaltung, Compliance, Substanzvermeidung, Sicherheitsorientierung, Ernährung und Hygiene. Der MGV-39 erwies sich als sensitiv für Geschlechtsunterschiede; das in der Literatur beschriebene Defizit von Männern in der Compliance, Substanzvermeidung, Sicherheitsorientierung und Hygiene (sowie im MGV) konnte repliziert werden. In einem weiteren Schritt wurde der Zusammenhang zwischen MGV und Vulnerabilität aus einer Geschlechterperspektive beleuchtet. Die Ergebnisse eines additiven hierarchischen Regressionsmodells wiesen auf, dass höheres Alter, weibliches Geschlecht, eine geringe Krankheitsanfälligkeit und eine hohe subjektive Gesundheit mit einem protektiven Verhaltensstil zusammenhingen: Personen schließen aus ihrem habituellen MGV auf ihre gegenwärtige und zukünftige Vulnerabilität. Die Überprüfung der Wechselwirkungen in einer moderierten hierarchischen Regression zeigte, dass das Geschlecht den Zusammenhang zwischen MGV und subjektiver Gesundheit moderierte. Für Männer war der Zusammenhang stärker ausgeprägt als für Frauen.
Interannual variability of the sea‐air exchange of CO2 from 1961 to 1998 simulated with a global ocean circulation‐biogeochemistry model
Authors: Obata Atsushi , Kitamura Yoshiteru
Published: November 2003

Interannual variability of global sea‐air CO2 flux is investigated by use of a numerical model for general and biogeochemical circulation with the observed interannual variations in sea surface temperature and wind stress from 1961 to 1998. The global variability is 0.23 GtC yr−1 as the standard deviation, and is governed by the variability of 0.13 GtC yr−1 in the equatorial Pacific through the El Niño‐Southern Oscillation (ENSO) cycle. The variability in the Southern Ocean is the second largest, 0.07 GtC yr−1. These features are reproduced in both the experiments using the wind stress from an atmospheric circulation model reanalysis (National Centers for Environmental Prediction (NCEP)) and that from an observational data set (Atlas of Surface Marine Data, 1994). Our results agree with the previous ocean‐based estimates on the points that the global variability is much smaller than the atmosphere‐based estimates (∼1 GtC yr−1) and that the global variability is governed by the equatorial Pacific. The variability in the equatorial Pacific is mostly influenced by the surface dissolved inorganic carbon (DIC) convergence in the wind‐driven velocity field; the reduced DIC convergence by the weakened easterly causes the reduced sea‐to‐air CO2 flux during El Niño. Variability of export production has an opposite effect to that of the surface DIC convergence in controlling the sea‐air CO2 flux in the ENSO cycle but is smaller than a half of the variability of the surface DIC convergence. Effect of surface temperature through the CO2 solubility is also opposite but is smaller by an order of magnitude. The sea‐air CO2 flux variability influenced by the ENSO is almost the same in both the early period (1961–1979) and the late period (1980–1998). The simulated variability in the equatorial Pacific is smaller, about 70% of the observational estimate. This deficiency is partly due to the underestimated effect of surface salinity variation on pCO2 caused by the climatological salinity boundary condition and partly due to the overestimated export production by the neglect of the effect of micronutrients in our production parameterization.
Rheology and strength of the Eurasian continental lithosphere in the foreland of the Taiwan collision belt: Constraints from seismicity, flexure, and structural styles
Authors: Mouthereau Frédéric , Petit Carole
Published: November 2003

Deformation in western Taiwan is characterized by variable depth‐frequency distribution of crustal earthquakes which are closely connected with along‐strike variations of tectonic styles (thin or thick skinned) around the Peikang High, a major inherited feature of the Chinese margin. To fit the calculated high crustal geotherm and the observed distribution of the crustal seismic activity, a Qz‐diorite and granulite composition for the upper and the lower crust is proposed. We then model the plate flexure, through Te estimates, using brittle‐elastic‐ductile plate rheology. Flexure modeling shows that the best fit combination of Te‐boundary condition is for thrust loads acting at the belt front. The calculated Te vary in the range of ∼15–20 km. These values are primarily a reflection of the thermal state of the rifted Chinese margin inherited from the Oligocene spreading in the South China Sea. However, other mechanical properties such as the degree of crust/mantle coupling and the thickness of the mechanically competent crust and mantle are considered. South of the Peikang High, flexure modeling reveals lower Te associated with thinner mechanically strong layers. Variable stress/strain distribution associated with a higher degree of crust/mantle decoupling is examined to explain plate weakening. We first show that plate curvature cannot easily explain strength reduction and observed seismic activity. Additional plate‐boundary forces arising from the strong coupling induced by more frontal subduction of a buoyant crustal asperity, i.e., the Peikang High, with the overriding plate are required. Favorably oriented inherited features in the adjacent Tainan basin produce acceleration of strain rates in the upper crust and hence facilitate the crust/mantle decoupling as attested by high seismic activity and thick‐skinned deformation. The relative weakening of the lower crust and mantle then leads to weaken the lithosphere. By contrast, to the north, more oblique collision and the lack of inherited features keep the lithosphere stronger. This study suggests that when the Eurasian plate enters the Taiwan collision, tectonic inheritance of the continental margin exerts a strong control on the plate deformation by modifying its strength.
Impact of isopycnal mixing on the tropical ocean circulation
Authors: Lengaigne M. , Madec G. , Menkes C. , Alory G.
Published: November 2003

The sensitivity of tropical ocean dynamics to the ocean lateral mixing orientation is explored using a z‐coordinate climate‐type ocean general circulation model. Compared to a simulation using horizontal mixing on both tracers and dynamics (HOR), a rotation of the tracer tensor in which mixing occurs along isopycnals (ISOT) improves the structure of the off‐equatorial density field, which consequently enhances the off‐equatorial circulation through geostrophy. However, the dynamics at the equator in ISOT are degraded compared to observations, as the upper part of the Equatorial Undercurrent (EUC) is too deep and the South Equatorial Current (SEC) is too intense. Next, isopycnal diffusion on momentum is implemented (ISOMT). An examination of the momentum balance at the equator shows that this change in lateral diffusion direction significantly reduces the meridional diffusive flux of momentum at the top of the EUC. This intensifies the EUC, which, in turn, weakens the SEC along the equator through vertical diffusion. The equatorial degradations observed in ISOT disappear. Compared to ISOT and HOR, the separation of the two SEC branches and the equatorial current magnitude in the surface layers are much better reproduced. Moreover, in contrast to the results from ISOT and HOR, isopycnal momentum mixing allows the existence of both horizontal up‐gradient and down‐gradient eddy momentum fluxes, notably improving the vertical profile of the lateral viscosity term. The ISOMT experiment is therefore shown to be the closest to observations. These results suggest that isopycnal mixing should be used on both tracers and momentum to better simulate the observed eddy effects and the tropical circulation in climate models.
Topographic steering of a mid‐depth drifter in an eddy‐like circulation region south and east of the Hawaiian Ridge
Authors: Thomson Richard E. , Freeland Howard J.
Published: November 2003

A Profiling Autonomous Lagrangian Current Explorer (PALACE float) deployed in June 1997 at a “parking depth” of 1250 m depth to the south of Hawaii drifted westward within the North Equatorial Current for about a year before stalling in a region of directionally variable, eddy‐like flow centered near 21°N, 168°W, within the intersection region of the Pacific Seamounts and Hawaiian Ridge. The float remained within the 5‐km‐deep, eddying regime for more than 3 years before ending communication in October 2001. During its year in the North Equatorial Current, the float traveled roughly 1400 km westward along ≈18°N latitude at a mean mid‐depth speed of 4.39 ± 2.19 cm s−1. Within the eddying region, mid‐depth currents remained relatively strong but directions became highly variable and the mean westward drift diminished to 0.05 ± 2.67 cm s−1. Close examination of the 15‐day trajectory data reveals that the float entered the eddying region after making an abrupt northward turn along the shallow (∼2000 m deep) eastern limb of the Pacific Seamounts. Similar depth‐related directional changes were frequently observed throughout the 3.4‐year drift within the eddying region, consistent with modification of the mid‐depth circulation by the underlying seafloor topography. On the basis of the density structure obtained along the float trajectory, only topographic features with scale lengths of roughly 50 km or more have a significant effect on the mid‐depth flow.
Eta model estimated land surface processes and the hydrologic cycle of the Mississippi basin
Authors: Berbery Ernesto Hugo , Luo Yan , Mitchell Kenneth E. , Betts Alan K.
Published: November 2003

This article discusses the water and surface energy budgets over the Mississippi River basin and subbasins using NCEP's Eta model forecasts. It also discusses the relation between surface states (soil moisture) and other variables that affect the surface energy balance, potentially interacting with precipitation processes. The Eta model is NCEP's operational mesoscale model and therefore has been subject to changes and upgrades over the period of this evaluation. While the atmospheric water cycle is analyzed here using a 7‐year long (June 1995 to May 2002) data set, the research focusing on surface processes is based on a 4‐year period (June 1998 to May 2002) after substantial upgrades to the land surface component were performed. On the 7‐year average the Eta model 12–36 h forecast precipitation averaged over the Mississippi basin differs from the observed precipitation by 2%, while the estimate of evaporation computed as a residual of the water balance equation differs by 5% from the evaporation estimate resulting from a data set of land surface fluxes prepared with the macroscale hydrologic variable infiltration model (VIC). However, the difference between the model parameterized evaporation and VIC's is about 17% due to excessive bare soil evaporation in the Eta model. Notably, the long‐term average of moisture flux convergence also estimated from the 12–36 h forecasts is 0.54 mm day−1 over the Mississippi basin, while streamflow observations at Vicksburg average 0.50 mm day−1. This agreement within 10% is a strict test of the quality of the hydrologic cycle estimates; therefore these are promising results for estimates of the water cycle from regional analysis or future regional reanalysis. Subbasins of the Mississippi have diverse land surface‐atmosphere interactions at monthly timescales. In the western half of the Mississippi basin, feedbacks can be described as follows: increased soil moisture is associated with a slight increase of net radiation at the surface; latent heat also increases with soil moisture while sensible heat decreases, resulting in an almost linear increase of the evaporative fraction. Increased soil moisture is also associated with a lower lifting condensation level and an increase of observed precipitation (though not statistically significant). The overall results support the concept of a positive feedback in which increased soil moisture affects surface fluxes in such a manner that increased precipitation results. However, toward the east (e.g., the Ohio basin), there are no well‐defined land surface‐atmosphere interactions, suggesting that other effects, like the advection of moisture, may be more relevant for precipitation processes.
A comparison of ocean emissivity models using the Advanced Microwave Sounding Unit, the Special Sensor Microwave Imager, the TRMM Microwave Imager, and airborne radiometer observations
Authors: Ellison W. J. , English S. J. , Lamkaouchi K. , Balana A. , Obligis E. , Deblonde G. , Hewison T. J. , Bauer P. , Kelly G. , Eymard L.
Published: November 2003

New measurements of the permittivity of saline water at millimeter wavelengths have the potential to improve the accuracy of ocean surface emissivity models for use with microwave and millimeter‐wave imaging and sounding instruments. Recent radiative transfer models employing a range of different treatments of surface ocean emissivity are compared with observations from the following microwave radiometers: Advanced Microwave Sounding Unit, Special Sensor Microwave Imager, TRMM Microwave Imager, Microwave Airborne Radiometer Scanning System, and Deimos. Emissivity models using the new permittivity model fit these observations more closely than those models which use the Klein and Swift extrapolation model.
Evaluation of the North American Land Data Assimilation System over the southern Great Plains during the warm season
Authors: Robock Alan , Luo Lifeng , Wood Eric F. , Wen Fenghua , Mitchell Kenneth E. , Houser Paul R. , Schaake John C. , Lohmann Dag , Cosgrove Brian , Sheffield Justin , Duan Qingyun , Higgins R. Wayne , Pinker Rachel T. , Tarpley J. Dan , Basara Jeffery B. , Crawford Kenneth C.
Published: November 2003

North American Land Data Assimilation System (NLDAS) land surface models have been run for a retrospective period forced by atmospheric observations from the Eta analysis and actual precipitation and downward solar radiation to calculate land hydrology. We evaluated these simulations using in situ observations over the southern Great Plains for the periods of May–September of 1998 and 1999 by comparing the model outputs with surface latent, sensible, and ground heat fluxes at 24 Atmospheric Radiation Measurement/Cloud and Radiation Testbed stations and with soil temperature and soil moisture observations at 72 Oklahoma Mesonet stations. The standard NLDAS models do a fairly good job but with differences in the surface energy partition and in soil moisture between models and observations and among models during the summer, while they agree quite well on the soil temperature simulations. To investigate why, we performed a series of experiments accounting for differences between model‐specified soil types and vegetation and those observed at the stations, and differences in model treatment of different soil types, vegetation properties, canopy resistance, soil column depth, rooting depth, root density, snow‐free albedo, infiltration, aerodynamic resistance, and soil thermal diffusivity. The diagnosis and model enhancements demonstrate how the models can be improved so that they can be used in actual data assimilation mode.
Crustal structure of the transpressional Variscan orogen of SW Iberia: SW Iberia deep seismic reflection profile (IBERSEIS)
Authors: Simancas J. F. , Carbonell R. , González Lodeiro F. , Pérez Estaún A. , Juhlin C. , Ayarza P. , Kashubin A. , Azor A. , Martínez Poyatos D. , Almodóvar G. R. , Pascual E. , Sáez R. , Expósito I.
Published: November 2003

IBERSEIS, a 303 km long (20 s) deep seismic reflection profile, was acquired across the Variscan belt in SW Iberian Peninsula. The acquisition parameters were designed to obtain a high‐resolution crustal‐scale image of this orogen. The seismic profile samples three major tectonic terranes: the South Portuguese Zone, the Ossa‐Morena Zone, and the Central Iberian Zone, which were accreted in Late Paleozoic times. These terranes show a distinctive seismic signature, as do the sutures separating them. Late strike‐slip movements through crustal wedges are apparent in the seismic image and have strongly modified the geometry of sutures. The upper crust appears to be decoupled from the lower crust all along the seismic line, but some deformation has been accommodated at deeper levels. A sill‐like structure is imaged in the middle crust as a 1–2 s thick and 175 km long high‐amplitude conspicuous reflective band. It is interpreted as a great intrusion of mafic magma in a midcrustal decollement. Taking into account surface geological data and the revealed crustal architecture, a tectonic evolution is proposed for SW Iberia which includes transpressional collision interacting during Early Carboniferous with a mantle plume. The Moho can be identified along the entire transect as subhorizontal and located at 10 to 11 s, indicating a 30–35 km average crustal thickness. Its seismic signature changes laterally, being very reflective beneath the South Portuguese Zone and the Central Iberian Zone, but discontinuous and diffuse below the Ossa Morena Zone.
The upper mantle discontinuity structure beneath eastern China
Authors: Ai Yinshuang , Zheng Tianyu
Published: November 2003

We apply a common conversion point stacking technique of receiver functions from the North China Interior Structure Project (NCISP) to image the upper mantle discontinuity structure beneath eastern China. The stacking results of dense receiver functions reveal a prominent discontinuity structure. The appearance of the 410‐km discontinuity is sharp and consistent with little influence by Western Pacific subduction slabs. The 520‐km discontinuity is relatively weak and consists of splitting phases at depths ranging from 500 km to 550 km. As for the 660‐km discontinuity, double discontinuities and a narrow depression zone are detected near a depth of 660‐km, indicating a more complex structure there. Phase transformations in non‐olivine components, such as from garnet to perovskite, seem to be a more plausible interpretation for a complex 660‐km discontinuity in this region.
Application of Artificial Neural Networks for the classification of the seismic transients at Soufrière Hills volcano, Montserrat
Authors: Langer H. , Falsaperla S. , Thompson G.
Published: November 2003

Seismic activity at Soufrière Hills volcano is characterized by a variety of transients, such as tectonic earthquakes, long‐period events, hybrid events, and rockfalls. The huge quantity of seismic data daily recorded on the volcano makes the application of automatic processing highly recommendable. We propose a method of supervised classification of the transients based on Artificial Neural Networks (ANN), which may be useful for processing the large data sets piled up in the past. Particularly, data sets recorded before the climactic eruptions from 1995 to 2002 may allow us to reconstruct the distribution of the different classes of seismic transients in time. We believe that this analysis may give useful insights into impending eruptive scenarios. The good performance of the ANN with 70% of transients correctly classified in a test set of 156 data, along with the opportunity to revise the misfits, make ANN a powerful tool for data processing.
Relationship between self‐potential (SP) signals and redox conditions in contaminated groundwater
Authors: Naudet V. , Revil A. , Bottero J.‐Y. , Bégassat P.
Published: November 2003

In situ measurements of redox potential are rather difficult to perform and provide only sparse information on its spatial distribution. To delineate redox fronts in a contaminant plume, the self‐potential (SP) method can be a helpful complement to geochemical measurements. Here, we apply the SP method to the Entressen municipal waste landfill (south‐eastern France) over a 20 km2 area. The results show a large negative SP‐anomaly of ∼−400 mV with respect to a reference station taken outside the contaminant plume. Once removed the electrokinetic component associated with groundwater flow, the residual self‐potential signals are linearly correlated with in situ measurements of redox potential. We propose a quantitative relationship between self‐potential and redox potential, which would be used to invert self‐potential measurements in terms of in situ redox potential values in contaminant plumes.
A 3‐D geodynamic model of lateral crustal flow during Andean mountain building
Authors: Yang Youqing , Liu Mian , Stein Seth
Published: November 2003

Although the Andes are believed to have resulted mainly from crustal shortening, the shortening history remains debated and appears to require lateral (along‐strike) crustal flow. Three‐dimensional viscous flow modeling shows that, within geological uncertainties, the Andes may have been produced by either Neogene shortening alone or with significant pre‐Neogene shortening. These scenarios require major along‐strike crustal flow and predict significantly different histories of uplift and crustal motion.
Acoustic waves in the upper mesosphere and lower thermosphere generated by deep tropical convection
Authors: Walterscheid R. L. , Schubert G. , Brinkman D. G.
Published: November 2003

A time‐dependent, nonlinear, fully compressible, axisymmetric, f‐plane, numerical model is used to simulate the propagation of acoustic waves in the mesosphere and thermosphere by intense deep convection in the troposphere. The simulations show that major convective storms in the tropics launch acoustic waves into the mesosphere‐thermosphere directly above the storm centers. The principal feature of the overhead acoustic wave field in the period interval of ∼3 to 5 min is a trapped oscillation below about 80 km altitude with a period of ∼5 min and a nearly vertically propagating wave with about a 3‐min period above this height. Acoustic oscillations in the troposphere‐mesosphere duct have a standing wave character directly over the storm; the oscillations that propagate off vertical mainly reflect off the top and bottom of the duct resulting in a horizontally propagating acoustic field within the duct. The acoustic oscillations that are mainly confined to the troposphere‐mesosphere duct persist for about an hour after the storm has ended. The vertically propagating thermospheric acoustic oscillations are waves propagating upward from the thunderstorm source through the stratosphere‐mesosphere. These predominantly 3‐min waves are strongly driven for ∼30 min after the storm event and weaken with time thereafter. The vertically propagating thermospheric acoustic waves may be the source of the F‐region 3‐min oscillations. Intense acoustic disturbances directly above thunderstorms may be responsible for localized heating of the thermosphere.
Atomic oxygen profiles (80–94 km) derived from Wind Imaging Interferometer/Upper Atmospheric Research Satellite measurements of the hydroxyl airglow: 1. Validation of technique
Authors: Russell Jason P. , Lowe R. P.
Published: November 2003

The use of satellite measurements of the hydroxyl airglow volume emission rate profile to infer the atomic oxygen profile of the mesopause region is complicated by uncertainties as to the collision de‐excitation mechanism and the vibration transition probabilities that are needed for the analysis. In this paper, we demonstrate that the shape of the derived atomic oxygen profiles is, to a large extent, independent of the choice of these factors. We use data from two nights of observation from the Wind Imaging Interferometer (WINDII) instrument onboard Upper Atmospheric Research Satellite (UARS) where the instrument observed the hydroxyl emission and the oxygen greenline emission on alternate orbits. The comparison between the derived atomic oxygen profiles from the two emissions is difficult because the region of overlap of good quality data lies in between the peaks and is small (about 4 km). Also, the altitude of the good overlap is not fixed but is a function of both latitude and local time and may lie anywhere in the altitude range from 88 to 94 km because the heights of the emission layers also change. We have adopted a technique of doing the comparison only at certain altitude/local time combinations depending on where the best data exists. The hydroxyl parameter set that used Goldman transition probabilities and a sudden death quenching model best fit the greenline derived atomic oxygen and will be used to complete a full atomic oxygen climatology from 80 to 110 km.
Optimal estimation of changes in the mass of ice sheets
Authors: Arthern Robert J. , Hindmarsh Richard C. A.
Published: November 2003

We describe a new approach for estimating changes in ice sheet mass. Two methods are in common use: the ice budget and geodetic methods. The first makes use of separate estimates of the mass fluxes into and out of a domain, differencing them to obtain the local mass balance. The second estimates mass balance directly, using measurements of the change in surface elevation, often from aircraft or satellites. Here we combine ice budget and geodetic approaches to obtain an optimal estimate of mass balance. We seek maximum likelihood solutions for three terms: (1) the rate of change of surface elevation, (2) the rate of snow accumulation, and (3) the local divergence of the ice flux. These estimates are constrained to obey the continuity equation. We allow the location and temporal averaging interval of the estimates to be chosen arbitrarily. This approach can use all relevant measurements. The fidelity of any measurement is lowered by measurement error, and by fluctuations in each of the three terms driven by random year‐to‐year snowfall variations. We take full account of both error sources, weighting the data so as to minimize the confounding effect of these influences. Realistic covariance between randomly forced fluctuations are provided by a linearized model of ice sheet flow. We test the approach by applying the algorithm to synthetically generated measurements. The method performs better than either ice budget or geodetic methods applied in isolation, and has the important advantage that good estimates may still be derived when measurements appropriate to either technique are lacking or inaccurate.
Random processes and geographic species richness patterns: why so few species in the north?
Authors: Bokma Folmer , Bokma Jurjen , Mönkkönen Mikko
Published: November 2003

In response to the suggestion that the latitudinal gradient in species richness is the result of stochastic processes of species distributions, we created a computer simulation program that enabled us to study random species distributions over irregularly shaped areas. Our model could not explain latitudinal variation in species richness of New World mammals and created species richness patterns that differed dramatically from previous stochastic models. The interplay of speciation and species migration in our simulation generated the highest species richness in the middle of a landmass, not in the middle of its latitudinal stretch as was found in previous one‐dimensional models. The discrepancy between the results of this study and previous empirical studies suggests that the effect of randomness in species‐richness distribution is on a continental scale restricted by other, dominant determinants that limit the effect of chance.
Local avian assemblages as random draws from regional pools
Authors: Blackburn T. M. , Gaston K. J.
Published: November 2003

It is becoming increasingly apparent that the ecological structure of local assemblages depends to some degree on the regional context within which they are embedded. Here, the structure of one such local assemblage, the avifauna of Eastern Wood, southern England, is modelled as a random draw from the pool of British deciduous woodland species. The random draw model accurately predicts most (>90%) of a suite of descriptive statistics calculated from the Eastern Wood avifauna, when the probability that a species is selected for inclusion in a random assemblage is weighted by its British geographic range size. Models for which a species selection is weighted by its British population size, or is unweighted, perform less well. This suggests that how widespread a species is in a region affects the likelihood that it will occur at any given local site, and hence that large‐scale patterns in the distribution of species can strongly influence the composition and structure of local assemblages.
Phytophagous insects and web‐building spiders in relation to pasture vegetation complexity
Authors: Borges Paulo A. V. , Brown Valerie K.
Published: November 2003

We investigate the potential use of structural characteristics of vegetation as predictors of the densities of pasture arthropods in three Azorean islands. Two types of upland pastures, recent sown pastures (3–4 yr old) and wet semi‐natural old pastures (>35 yr old), were studied in three Azorean islands (S. Maria, Terceira and Pico). Three arthropod assemblages, of particular importance in pasture habitats, were assessed: insect forb‐feeders, insect grass‐feeders and web‐building spiders. These are numerically abundant and represent a range of feeding strategies. Point quadrats for plants and suction (Vortis) for arthropods were used as sampling methods. Several vegetation indices were investigated, but only three (cover abundance of perennial forbs, cover abundance of perennial grasses and the total vegetation alpha‐diversity) were good predictors of invertebrate abundance. Vegetation structure, defined by a Height Index, was of minor predictive value. In sown and semi‐natural pastureland, diverse and structurally complex pasture sites support more individual insect forb‐feeders, grass‐feeders and web‐building spiders per unit area than less complex ones.
The Industry View on Long‐Term Toxicology Testing in Drug Development of Human Pharmaceuticals
Authors: Van Cauteren Herman , Bentley Philip , Bode Gerd , Cordier André , Coussement Werner , Heining Peter , Sims Jenny
Published: November 2003

Abstract: The approach to chronic toxicity testing over the past decade is reviewed and assessed in the light of developing ICH guidelines. The 1990’s have seen a general acceptance that studies with a maximal duration of 6 months in rodents are all that is required for adequate safety assessment of developmental pharmaceutical agents. However, controversy has arisen concerning the most appropriate duration for chronic toxicity testing in non‐rodents. Initial suggestions that 6 months duration was sufficient have been countered by findings noted in 12‐month studies that were not seen in shorter‐term studies. Retrospective analysis of available data eventually lead to a subsequent ICH recommendation that studies of 9 months duration would be now acceptable. However, until recently the FDA position on this recommendation was unclear and an analysis of industry practices since the ICH recommendation was made in 1997 has shown that the 9‐month guideline is not widely applied. Recent clarification by the FDA will probably result in a continued but limited use of this alternative. An industry view on the future of chronic toxicology testing in rodents and non‐rodents is presented.
Pharmacovigilance Based on Prescription Databases
Authors: Gram Lars F. , Hallas Jesper , Andersen Morten
Published: November 2003

Abstract: Prescription databases are indispensible in drug safety research and surveillance. For suspected rare serious adverse drug reactions, the confirmation and quantitative risk assesment requires proper epidemiological studies. Often prescription databases provide the information on drug exposure for such studies. Abberant drug utilization in terms of overuse, underuse, polypharmacy etc. may be a threat to the health of the patient, and these aspects can best be studied by prescription databases. In cases of international drug safety alerts, prescription databases may provide information required for rational actions to be taken.
Spontaneous ADR Reporting and Drug Safety Signal Induction in Perspective
Authors: Edwards I. Ralph
Published: November 2003

Abstract: Drug safety signals will continue to come mainly from the reporting of alert clinicians and every effort should be made to enhance this and to ease the process. The use of multipurpose health databases for finding signals has much potential, if they are better planned so that the appropriate data is captured and examined routinely. Consumer reports give us information about their concerns and should not be ignored. Better information is needed on poisoning, drug misuse and on herbal remedies. The analysis of signals must be improved and speeded up, if we are even to maintain our current safety standards, given the global release of ‘blockbuster products’. Benefit‐risk analysis of medicines needs to be better understood in relationship to actual clinical use, both from an individual and public health perspective. Such analysis should become more logical rather than just listing the benefits and risks, and then expressing an essentially unsupported opinion. This is essential if therapies are to be compared, and their costs justified. The communication of medicines safety and benefit‐risk information to clinicians, other health professionals and patients is an area where there needs to be considerable improvements. We need to be better informed about the consequences of guidance and warnings given, so that we may improve the service we offer to recipients. In the future, information technology, which provides exciting possibilities with what it offers now, will help us with all the above challenges.
International Pharmacovigilance: Developing Cooperation to Meet the Challenges of the 21st Century
Authors: Lumpkin Murray M.
Published: November 2003

Abstract: Much has been accomplished internationally in the past decade to harmonise the much of the process of post‐marketing drug risk detection. However, formidable challenges exist in harmonising analytical approaches to such data and in leveraging international database resources to improve the quality of such data. In addition, international challenges continue in the arena of drug risk management once a specific risk has been detected. Especially problematic are the questions of appropriate methodology and metrics to assess the public health impact of our risk management techniques. Finally, international challenges remain in the world of drug risk communication to practitioners, dispensers, and patients. The primary challenge confronting us is that of providing easily accessible, understandable, unbiased information on drug risk to these communities so that truly informed decisions about medicines can be made at the individual patient level. Only by meeting internationally these challenges in drug risk detection, management, and communication can our citizens know how to best use these wonderful pharmacological gifts to which we now have access.
Safety of Biotechnological Products
Authors: Bass Rolf , Purves J. , Amati M. Papaluca
Published: November 2003

Abstract: The safety of biotechnological products used for medicinal products is addressed by EU council directives. The general principles and the regulatory framework for the handling of new drug applications within this areas are described both with respect to benefit/risk evaluation, quality assessment, preclinical safety and efficacy testing.
New Safe Medicines Faster: A Proposal for a Key Action within the European Union’s 6th Framework Programme
Authors: Bjerrum Ole J.
Published: November 2003

Abstract: The global competitiveness of the European pharmaceutical industry is under threat. Technology currently available for the development of new medicines is unable to match the pace of drug discovery and design; and the ever‐growing demand for safety, efficacy and quality documentation has increased the cost and time involved in getting new medicines on the market. Although the pharmaceutical industry is one of the strongest in Europe in terms of research, innovation, exports and employment, there are severe restrictions on its ability to create wealth and launch safe drugs for the treatment of common and rare afflictions. The present situation should not be allowed to continue. For this reason, the European Federation for Pharmaceutical Sciences (EUFEPS) has proposed a key action under the title “New safe medicines faster” for the forthcoming EU 6th RTD framework programme. The key action has three main objectives: to seek new technologies capable of more effective selection of potential drug candidates for innovative medicines while accommodating safety demands; to use such technologies to speed up the pharmaceutical development process and eliminate bottlenecks created by initial exploratory drug research; and to cultivate a pan‐European interdisciplinary network that bridges the gap between industry, academia and regulatory authorities. By involving regulatory authorities early on and fuelling research and innovation with EU money it should be possible to create a new set of recognised European standards whereby new safe medicines can be brought onto the market faster and cheaper.
Mechanism of acidic pH‐induced contraction in spontaneously hypertensive rat aorta: role of Ca2+ release from the sarcoplasmic reticulum
Authors: Rohra D. K. , Saito S.‐Y. , Ohizumi Y.
Published: November 2003

Aim: 
This study was conducted to investigate the mechanism of acidic pH‐induced contraction (APIC) with regard to Ca2+ handling using isometric tension recording experiments.

Results:  Decreasing extracellular pH from 7.4 to 6.5 produced a marked and sustained contraction of spontaneously hypertensive rat (SHR) aorta, that was 128.7 ± 2.0% of the 64.8 mm KCl‐induced contraction. Verapamil, an inhibitor of voltage‐dependent Ca2+ channels (VDCC) significantly inhibited the APIC. In Ca2+‐deficient solution, sustained contraction induced by acidic pH was abolished completely, while a transient contraction was still observed suggesting the release of Ca2+ from intracellular site. Ryanodine (1 μm), a ryanodine receptor blocker, and 10 μm cyclopiazonic acid (CPA; a sarco/endoplasmic reticulum Ca2+ ATPase inhibitor) abolished the transient contraction induced by acidosis. In normal Ca2+‐containing solution, ryanodine significantly decreased the rate of rise as well as maximum level of APIC. Interestingly, ryanodine and CPA showed an additive inhibitory effect with verapamil and the combined treatment of ryanodine or CPA with verapamil nearly abolished the APIC.

Conclusions:  It is concluded that acidic pH induces Ca2+ release from ryanodine/CPA‐sensitive store of sarcoplasmic reticulum in SHR aorta. This Ca2+ plays an important role in the facilitation of the rate of rise of APIC, as well as contributing to the sustained contraction via a mechanism which is independent of Ca2+ influx through VDCC.