bluuebunny/crossref_metadata_2025 huggingface dataset:
An improved nucleic acid parameter set for the GROMOS force field
Authors: Soares Thereza A. , Hünenberger Philippe H. , Kastenholz Mika A. , Kräutler Vincent , Lenz Thomas , Lins Roberto D. , Oostenbrink Chris , van Gunsteren Wilfred F.
Published: March 2005

Over the past decades, the GROMOS force field for biomolecular simulation has primarily been developed for performing molecular dynamics (MD) simulations of polypeptides and, to a lesser extent, sugars. When applied to DNA, the 43A1 and 45A3 parameter sets of the years 1996 and 2001 produced rather flexible double‐helical structures, in which the Watson–Crick hydrogen‐bonding content was more limited than expected. To improve on the currently available parameter sets, the nucleotide backbone torsional‐angle parameters and the charge distribution of the nucleotide bases are reconsidered based on quantum‐chemical data. The new 45A4 parameter set resulting from this refinement appears to perform well in terms of reproducing solution NMR data and canonical hydrogen bonding. The deviation between simulated and experimental observables is now of the same order of magnitude as the uncertainty in the experimental values themselves. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 725–737, 2005
LC‐PDA and LC‐ESI‐MS separation and determination of process‐related substances arising from stilbene‐type fluorescent whitening agents. Application to monitoring of their photodegradation products in industrial effluents and aqueous environmental systems
Authors: Rao R. Nageswara , Venkateswarlu N. , Khalid Sara , Narsimha R.
Published: March 2005

A simple and rapid gradient elution high‐performance liquid chromatographic method using photodiode array and electrospray ionization mass spectrometric detectors was developed for separation and determination of the process‐related substances and photodegradation products of stilbenesulfonic acids, viz. 4,4´‐dinitrostilbene‐2,2´‐disulfonic acid (DNSDA), 4‐amino‐4´‐nitrostilbene‐2,2´‐disulfonic acid (ANSDA), and 4,4´‐diaminostilbene‐2,2´‐disulfonic acid (DASDA) in industrial waste waters. Gradient elution was carried out using ammonium acetate and acetonitrile as mobile phase and an Inertsil‐ODS 3V column for separation. The negative‐ion electrospray ionization mass spectra containing [M–H]– ions of sulfonic acids allowed molecular mass determination of unknowns and the structures were proposed on the basis of the fragment ions in the MS/MS spectra.
Thioacetamide chemically immobilized on silica gel as a solid phase extractant for the extraction and preconcentration of copper(II), lead(II), and cadmium(II)
Authors: Xie Zeng Hong , Xie Fa Zhi , Guo Liang Qia , Lin Xu Cong , Chen Guo Nan
Published: March 2005

Thioacetamide immobilized on silica gel was prepared via the Mannich reaction. The extraction and enrichment of copper(II), lead(II), and cadmium(II) ions from aqueous solutions has been investigated. Conditions for effective extraction are optimized with respect to different experimental parameters in both batch and column processes prior to their determination by flame atomic absorption spectrometry (FAAS). The optimum pH ranges for quantitative adsorption are 4.0–8.0, 2.0–7.0, and 5.0–10.0 for Pb(II), Cu(II), and Cd(II), respectively. Pb(II) and Cd(II) can be desorbed with 3 mol/L and 0.1 mol/L HCl/HNO3, and Cu(II) can be desorbed with 2.5% thiourea. The adsorption capacity of the matrix has been found to be 19.76, 16.35, and 12.50 mg/g for Pb(II), Cu(II), and Cd(II), respectively, with the preconcentration factor of ≈300 for Pb(II) and ≈200 for Cu(II) and Cd(II). Analytical utility is illustrated in real aqueous samples generated from distilled water, tap water, and river water samples.
Homoleptic lanthanide guanidinate complexes: The effective initiators for the polymerization of trimethylene carbonate and its copolymerization with ε‐caprolactone
Authors: Zhou Liying , Sun Hongmei , Chen Jinglei , Yao Yingming , Shen Qi
Published: March 2005

The ring‐opening polymerization of trimethylene carbonate (TMC) using homoleptic lanthanide guanidinate complexes [RNC(NR′2)NR]3Ln as single component initiators has been fully investigated for the first time. The substituents on guanidinate ligands and center metals show great effect on the catalytic activities of these complexes, that is, N(CH2)5 > NiPr2 > NPh2 (for R′), Cy > iPr (for R), and Yb > Sm > Nd. Among them, [Ph2NC(NCy)2]3Yb shows the highest catalytic activity. Some features and kinetic behaviors of the TMC polymerization initiated by [Ph2NC(NCy)2]3Yb were studied in detail. The polymerization rate is first order, with the monomer concentration and Mn of the polymer increasing with the polymer yield increasing linearly. The results indicated the present system having “living character.” A mechanism that the polymerization occurs via acyl‐oxygen bond cleavage rather than alkyl‐oxygen bond cleavage was proposed. The copolymerization of TMC with ϵ‐caprolactone (ε‐CL) initiated by [Ph2NC(NCy)2]3Yb was also tested. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1778–1786, 2005
Syntheses and characterizations of aniline/butylthioaniline copolymers: Comparisons of copolymers prepared by the new concurrent reduction and substitution route and the conventional oxidative copolymerization method
Authors: Han Chien‐Chung , Yang Ku‐Feng , Hong Shih‐Ping , Balasubramanian Arumugam , Lee Yi‐Te
Published: March 2005

New highly solution‐processable aniline/butylthioaniline copolymers were prepared via oxidative copolymerization (OCP) and by concurrent reduction and substitution (CRS). Butylthio‐substituted polyaniline obtained via the CRS route (Pan‐SBu), being in line with the expected property changes after the addition of an electron‐donating substituent to an aromatic ring, displayed a lowered redox potential (E0) and a redshifted maximum wavelength (λmax; ultraviolet–visible) in comparison with its parent unsubstituted polyaniline (Pan). However, copolymers CP1–CP4 (obtained via the OCP method) displayed opposite behaviors, showing higher E0 values and blueshifts in λmax than the unsubstituted Pan. The results suggested that CP1–CP4 had shorter conjugation lengths than the unsubstituted Pan, possibly because of their chain conjugation defects (e.g., 1,3‐ring linkage structures), as evidenced by IR studies. The results of 1H NMR studies also indicated that Pan‐SBu had much higher structural homogeneity than copolymer CP4. Because the CRS synthetic route involved no backbone alternations, the resultant copolymer (Pan‐SBu) should have maintained the same backbone structure and hence the high conductivity of the parent unsubstituted Pan. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1767–1777, 2005
Ground‐ice stratigraphy and formation at North Head, Tuktoyaktuk Coastlands, western Arctic Canada: a product of glacier–permafrost interactions
Authors: Murton Julian B.
Published: March 2005

Glacially deformed permafrost at North Head, in the Tuktoyaktuk Coastlands of western Arctic Canada, contains a complex ground‐ice stratigraphy that formed during the course of the last glacial–interglacial cycle. Two generations of ground ice are distinguished within a single stratigraphic sequence. Pre‐deformation ice has been glacially deformed or eroded beneath the cold‐based margin of the Laurentide Ice Sheet (LIS) during Marine Isotope Stage 2. Such ice comprises (1) buried basal ice, (2) massive segregated ice and (3) ice clasts subglacially eroded from pre‐existing ground ice. In contrast, post‐deformation ice has not been glacially disturbed because it formed during or after deglaciation; it includes (4) dykes and sills of intrusive ice, (5) massive segregated‐intrusive ice, (6) ice wedges and composite wedges, (7) segregated ice and (8) pool ice.

The superimposition of post‐deformation intrusive ice and massive segregated‐intrusive ice into permafrost containing pre‐deformation ground ice indicates that substantial quantities of overpressurized water were injected into ice‐marginal permafrost during or after deglaciation. The required external water source for the post‐deformation intrusive ice was probably overpressurized subpermafrost groundwater in front of the retreating margin of the LIS. Injection of this water into proglacial permafrost hydraulically fractured the permafrost and formed ice dykes, ice sills and massive segregated‐intrusive ice.

A two‐stage model of massive‐ice development can be reconciled with known permafrost and glacial conditions in the ice‐marginal context of the Late Wisconsinan LIS. The model probably applies to some other glaciated terrains of the western Canadian Arctic. Copyright © 2005 John Wiley & Sons, Ltd.
The transient layer: implications for geocryology and climate‐change science
Authors: Shur Yuri , Hinkel Kenneth M. , Nelson Frederick E.
Published: March 2005

Research treating permafrost‐climate interactions is traditionally based on a two‐layer conceptual model involving a seasonally frozen active layer and underlying perennially frozen materials. This conceptualization is inadequate to explain the behaviour of the active‐layer/permafrost system over long periods, particularly in ice‐rich terrain. Recent research in North America supports earlier Russian conclusions about the existence of a transition zone that alternates in status between seasonally frozen ground and permafrost over sub‐decadal to centennial time scales. The transition zone is ice‐enriched, and functions as a buffer between the active layer and long‐term permafrost by increasing the latent heat required for thaw. The existence of the transition zone has an impact on the formation of a cryogenic soil structure, and imparts stability to permafrost under low‐amplitude or random climatic fluctuations. Despite its importance, the transition zone has been the focus of relatively little research. The impacts of possible global warming in permafrost regions cannot be understood fully without consideration of a more realistic three‐layer model. The extensive data set under development within the Circumpolar Active Layer Monitoring (CALM) program will provide a significant source of information about the development, characteristics, behaviour, and extent of the transition zone. This paper is focused on the uppermost part of the transition zone, which joins the active layer at sub‐decadal to multi‐centennial time scales. This upper part of the transition zone is known as the transient layer. Copyright © 2005 John Wiley & Sons, Ltd.
In‐situ formed nanoparticles on 3C–SiC film under femtosecond pulsed laser irradiation
Authors: Dong Yuanyuan , Molian Pal
Published: March 2005

Nanoparticles in‐situ formed on single crystalline SiC films under femtosecond pulsed laser irradiation were characterized by SEM, AFM, AES, and Raman scattering. The size, shape, composition and internal stress of nanoparticles were investigated with respect to energy fluences. Femtosecond laser induced Coulomb explosion is most likely responsible for synthesis of highly oriented nanoparticles within a certain range of energy fluences. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of vertical‐cavity surface‐emitting laser structures by modulation spectroscopy: A status report
Authors: Klar P. J. , Karcher C. , Metzger B. , Hosea T. J. C.
Published: March 2005

In recent years, various modulation spectroscopic methods have been successfully applied for characterizing vertical‐cavity surface‐emitting laser structures. We will survey the field and its present status describing the experiments performed so far, in particular, focussing on photomodulated reflectance and contactless electroreflectance experiments and the corresponding line shape models. We will summarize the successes of the methods, but we will also highlight open questions for future studies. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Combined photo‐ and wavelength‐modulation spectroscopy of quantum well structures
Authors: Čechavičius B. , Kavaliauskas J. , Krivaitė G.
Published: March 2005

A spectroscopic technique that combines photoreflectance (PR) and wavelength‐modulated reflectance (WMR) spectroscopies was developed. This technique, which indeed is a second derivative spectroscopy, is based on measurements of a difference in the WMR with and without illumination of the sample. The combined modulation technique was used to study excitonic transitions and their photomodulation mechanisms in GaAs/AlAs quantum well structures. The enhancement of weak optical features and suppression of background effects as well as the possibility of studying changes in excitonic transitions induced both by modulated and continuous laser illumination are considered to be advantages of proposed modulation spectroscopy method. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reappraisal of Surgical Treatment for Radiation Enteritis
Authors: Onodera Hisashi , Nagayama Satoshi , Mori Akira , Fujimoto Akihisa , Tachibana Tsuyoshi , Yonenaga Yoshikuni
Published: March 2005

Although radiation enteritis is a well‐recognized sequel of therapeutic irradiation, the standard surgical method is not universally agreed upon. Not only the short‐term effect but also the long‐term effect after a surgical intervention has been fairly well reported. To reassess the surgical therapy for radiation enteritis, we retrospectively analyzed 48 patients (5 males and 43 females, mean age 58.6 years) who had been operated on in our department. These patients were divided into two types according to the time of surgery or the clinical manifestation, and operative methods were analyzed. Patient’s status such as bowel movement, body weight, and serum albumin value after surgery were analyzed, together with the patients survival. Our surgical methods were small intestinal resection for the intestinal obstruction, and pull‐through reconstruction for proctitis. Two patients died of multiple organ failure caused by perforated peritonitis irrespective of emergent operation. Although the overall morbidity was 21.7%, there was no leakage when bowels were anastomosed. Overall survival after radiation‐related complication in patients without previous neoplastic disease recurrence was 89%, 79%, and 69%, at 1, 3, and 5 years after surgery, respectively. Bowel motility, serum albumin level, and body weight recovered gradually soon after the operation and reached satisfactory levels within 6 months. Our analysis showed that small bowel injury should be treated by generous resection of the affected bowel followed by careful anastomosis of the disease‐free ends, while rectal resection is best dealt with by restorative proctectomy. This may provide a good quality of life and minimize major postoperative complications such as leakage.
Pancreatogastrostomy after Pancreatoduodenectomy: A Safe, Feasible Reconstruction Method?
Authors: Standop Jens , Overhaus Marcus , Schaefer Nico , Decker Dorothee , Wolff Martin , Hirner Andreas , Tuerler Andreas
Published: March 2005

Pancreatogastrostomy is a safe reconstructive technique after pancreatoduodenectomy, even when performed as an educational operation in the hands of relatively inexperienced surgeons in a high‐volume hospital. Sixteen surgeons with various case volumes operated on 190 consecutive patients and performed pancreatogastrostomy after pancreatoduodenectomy within the last 15 years in a university teaching hospital. Resections were performed for tumors localized in the head of the pancreas, the ampulla of Vater, or the distal common bile duct or duodenum (n = 169); for chronic pancreatitis (n = 16); and for miscellaneous reasons in five cases. The main outcome measures were postoperative mortality and morbidity, particularly the pancreatic leakage rate with special regard to the case volume of the performing surgeon. The overall mortality rate was 4.2% (n = 8), the 30‐day mortality rate was 3.2% (n = 6), and mortality directly related to surgery was 2.6% (n = 5). Morbidity occurred in 45%, including severe surgical complications, which required reoperation (9%), and minor surgical complications that could be managed conservatively (30%). There were no significant differences in overall surgical morbidity rates when the groups with varying patient volume per surgeon were compared. The incidence of pancreatic leakage was 7.4%, which did not contribute to mortality in any case and showed no statistical differences between the surgical volume groups. We concluded that pancreatogastrostomy is safe and feasible even in the hands of inexperienced but supervised surgeons. The leakage rate is similar to the data from other high‐volume centers. Once a leak is established, it can easily be managed conservatively, so it rarely contributes to severe complications or causes subsequent mortality. We recommend pancreatogastrostomy as a beneficial alternative to pancreatojejunostomy, even in the case of low surgical volume.
Acetylcholine from vagal stimulation protects cardiomyocytes against ischemia and hypoxia involving additive non‐hypoxic induction of HIF‐1α
Authors: Kakinuma Yoshihiko , Ando Motonori , Kuwabara Masanori , Katare Rajesh G. , Okudela Koji , Kobayashi Masanobu , Sato Takayuki
Published: March 2005

Electrical stimulation of the vagal efferent nerve improves the survival of myocardial infarcted rats. However, the mechanism for this beneficial effect is unclear. We investigated the effect of acetylcholine (ACh) on hypoxia‐inducible factor (HIF)‐1α using rat cardiomyocytes under normoxia and hypoxia. ACh posttranslationally regulated HIF‐1α and increased its protein level under normoxia. ACh increased Akt phosphorylation, and wortmannin or atropine blocked this effect. Hypoxia‐induced caspase‐3 activation and mitochondrial membrane potential collapse were prevented by ACh. Dominant‐negative HIF‐1α inhibited the cell protective effect of ACh. In acute myocardial ischemia, vagal nerve stimulation increased HIF‐1α expression and reduced the infarct size. These results suggest that ACh and vagal stimulation protect cardiomyocytes through the PI3K/Akt/HIF‐1α pathway.
Indicators for ecosystem-based management on the Scotian Shelf: bridging the gap between theory and practice
Authors: O'Boyle R. , Sinclair M. , Keizer P. , Lee K. , Ricard D. , Yeats P.
Published: March 2005

The need for a more integrated approach to ocean management is increasingly being recognized. Discussion on appropriate indicators and reference points supporting such an approach has focused on the technical merits of one set of metrics over another in servicing some management goal. Relatively little effort has been put into answering the question how one would use suites of indicators to meet the multiple conservation objectives defined in operational plans. Such an exercise is being undertaken on the eastern Scotian Shelf off Canada's east coast, as a national integrated management pilot. A number of ocean industries – fishing, oil and gas exploration, transport, and the military – utilize the area, a typical situation elsewhere in the world. A suite of conceptual ecosystem-level objectives has been identified to address biodiversity, productivity, and habitat issues. Operational objectives, which identify an indicator and reference points associated with each conceptual objective, are then stated. Utilizing this framework, individual ocean industry plans and activities can be reviewed in a consistent manner, to determine how they might be constrained by the conservation objectives for the area. Issues of spatial scale and cumulative impacts are addressed, and comment is made on future developments.
Social Policy Digest Online
Authors: Bennett Fran , Jones Ken
Published: March 2005

The Social Policy Digest went online in the summer of 2003. This means that the Digest, which used to be printed as part of the Journal of Social Policy, is now only available via the web.
Ground‐based assessment of Total Ozone Mapping Spectrometer (TOMS) data for dust transport over the northeastern Mediterranean
Authors: Kubilay Nilgün , Oguz Temel , Koçak Mustafa , Torres Omar
Published: March 2005

Multiyear daily surface aerosol aluminum (Al) concentration and sunphotometer measurements at Erdemli (Turkey) sampling station were used to assess the performance of Absorbing Aerosol Index (AAI) and Aerosol Optical Thickness (AOT) retrieved from the daily Total Ozone Mapping Spectrometer (TOMS) over the northeastern Mediterranean. A total of 98 moderate‐to‐high intensity dust events with durations from 1 day to 1 week were identified by aerosol Al concentrations and/or TOMS‐AAI above their threshold values of 1.0 μg m−3 and 0.5, respectively. Only 15 events were found to bring appreciable dust load into the northeastern Mediterranean, predominantly below the 850‐hPa pressure level, and therefore were not detected effectively by TOMS. Eight of these events corresponded to short‐range high intensity intrusions (Al > 3.0 μg m−3) from nearby dust sources of the Middle East and Arabian deserts, the rest (seven events) represented moderate‐to‐high intensity (Al > 1.0 μg m−3) long‐range transport from North Africa. Given the highly complex dynamics of the region, the use of TOMS‐AAI data is justified for monitoring Saharan dust transport characteristics in the northeastern Mediterranean. Moreover, the TOMS‐AOT data were found to covary linearly with its counterpart obtained by the ground‐based measurements (correlation coefficient 0.86, significant at <0.001), which lies within the range of estimates suggested by earlier studies.
Transmission of ENSO signal to the Indian Ocean
Authors: Cai Wenju , Meyers Gary , Shi Ge
Published: March 2005

The dynamics of El Niño‐Southern Oscillation (ENSO) cycles has previously been interpreted in terms of discharge and recharge of mass and heat in the equatorial Pacific. Some of the ENSO discharge/recharge signals transmit into the Indian Ocean, but the pathway is yet to be fully established. This study reveals a previously un‐noticed subtropical North Pacific (NP) pathway. NP Rossby waves associated with ENSO impinge on the western boundary and move equatorward along the “ray‐path” of Kelvin‐Munk waves, and reflect as equatorial Kelvin waves. En‐route to the equator, the waves are reinforced by wind stress anomalies associated with ENSO. The reflected equatorial Kelvin waves impinge on the Australasian continent and move poleward along the northern western Australia (WA) coast as coastally‐trapped waves, radiating Rossby waves into the south Indian Ocean. In this way, some 55% of the total interannual variance of the WA thermocline is linked to the subtropical NP Rossby waves.
Observations and model predictions of substorm auroral asymmetries in the conjugate hemispheres
Authors: Østgaard N. , Tsyganenko N. A. , Mende S. B. , Frey H. U. , Immel T. J. , Fillingim M. , Frank L. A. , Sigwarth J. B.
Published: March 2005

Based on imaging data from the Polar VIS Earth camera and the IMAGE‐FUV instruments we have documented how the IMF orientation and the dipole tilt angle act as the main and the secondary controlling factors of the relative displacement of the aurora in the conjugate hemispheres. Comparing our results with the asymmetries predicted by recent empirical magnetospheric models, we show that the assumed partial penetration of the IMF into the magnetosphere is clearly supported by observations, but the modeled conjugate shifts were found to be an order of magnitude smaller than the observed ones.
Implications of rapid planetary rotation for the Dungey magnetotail of Saturn
Authors: Milan S. E. , Bunce E. J. , Cowley S. W. H. , Jackman C. M.
Published: March 2005

Employing our current understanding of the structure and dynamics of Saturn's magnetosphere, we present a time‐dependent model of the kronian Dungey cycle magnetotail, which is based upon a modification of a similar model developed for Earth's magnetotail (Milan, 2004a). The major difference arises due to the rapid rotation of Saturn and the partial corotation that this imposes on the open field lines threading the polar cap. This results in twisted tail lobes, with the form of concentric cylinders of oldest to newest open flux from the inside out. The oldest, and hence longest, open field lines form the backbone of a highly extended magnetotail. Surrounding this are bundles of field lines disconnected by tail reconnection, propagating down‐tail at the solar wind speed. Owing to the twisted nature of the tail, these bundles remain entangled with the lobe cores to form “exterior flux ropes.” In the limit that the addition and removal of open flux from the magnetosphere by magnetic reconnection can be treated as a last‐in‐first‐out system, we formulate a description of the flux transport within the tail and drive this with estimated dayside reconnection voltages deduced from Cassini observations of the IMF made upstream of Saturn (Jackman et al., 2004).
Whistlers observed by the Cluster spacecraft outside the plasmasphere
Authors: Platino M. , Inan U. S. , Bell T. F. , Gurnett D. A. , Pickett J. S. , Canu P. , Décréau P. M. E.
Published: March 2005

Lightning generated whistlers are ubiquitous within the plasmasphere at both high and low altitudes, and these waves propagate efficiently in both ducted and nonducted modes. On the other hand, in the magnetospheric region outside the plasmasphere, lightning‐generated whistlers are commonly observed at low altitudes (up to ∼6000 km) but only rarely at higher altitudes near the magnetic equatorial plane. The reasons for the lack of these waves at higher altitudes are not well understood. In the present paper we use data from the Wide Band Plasma (WBD) instruments on the four Cluster spacecraft to study the characteristics of lightning‐generated whistlers observed on 4 separate days in 2001 at L shells ranging from L = 4 to L = 5, magnetic latitudes ranging from −20° to 10°, and Kp indices ranging from 3 to 6. The propagation paths of the lightning‐generated whistlers are determined using a two‐dimensional ray‐tracing model to calculate the ray paths and group delays from the lower ionosphere to each of the four Cluster spacecraft over a range of frequencies (1 kHz < f < 8 kHz). The electron density distributions used for the ray‐tracing calculations are derived from measurements with the Whisper relaxation sounder instrument. Our new results indicate that whistlers are observed outside the plasmasphere in the low‐density regions only in the presence of large‐scale irregularities within which the waves are “ducted.” This conclusion is sustained by an exhaustive search of whistlers outside the plasmasphere using all the Cluster passes during 2001 and 2002. In all the cases we found that dispersion characteristics are matched by ray‐tracing simulations only if the whistlers are ducted. In some cases, whistler wave energy injected by an individual lightning discharge appears with significant smearing in time. The new results presented in this paper support a possible explanation of why whistlers outside the plasmasphere are rarely observed, based on wave conversion electromagnetic whistler mode to quasi‐electrostatic lower hybrid mode (Bell et al., 2004).
Importance of small earthquakes for stress transfers and earthquake triggering
Authors: Helmstetter Agnès , Kagan Yan Y. , Jackson David D.
Published: March 2005

We estimate the relative importance of small and large earthquakes for static stress changes and for earthquake triggering, assuming that earthquakes are triggered by static stress changes and that earthquakes are located on a fractal network of dimension D. This model predicts that both the number of events triggered by an earthquake of magnitude m and the stress change induced by this earthquake at the location of other earthquakes increase with m as ∼10Dm/2. The stronger the spatial clustering, the larger the influence of small earthquakes on stress changes at the location of a future event as well as earthquake triggering. If earthquake magnitudes follow the Gutenberg‐Richter law with b > D/2, small earthquakes collectively dominate stress transfer and earthquake triggering because their greater frequency overcomes their smaller individual triggering potential. Using a southern California catalog, we observe that the rate of seismicity triggered by an earthquake of magnitude m increases with m as 10αm, where α = 1.05 ± 0.05. We also find that the magnitude distribution of triggered earthquakes is independent of the triggering earthquake's magnitude m. When α ≈ b, small earthquakes are roughly as important to earthquake triggering as larger ones. We evaluate the fractal correlation dimension D of hypocenters using two relocated catalogs for southern California. The value of D measured for distances 0.1 < r < 5 km is D = 1.54 for the Shearer et al. catalog and D = 1.73 for the Hauksson et al. catalog. The value of D reflects both the structure of the fault network and the nature of earthquake interactions. By considering only those earthquake pairs with interevent times larger than 1000 days, we can largely remove the effects of short‐term clustering. Then D ≈ 2, close to the value D = 2α = 2.1 predicted by assuming that earthquake triggering is due to static stress. The value D ≈ 2b implies that small earthquakes are as important as larger ones for stress transfers between earthquakes and that considering stress changes induced by small earthquakes should improve models of earthquake interactions.
Detection of tropical deep convective clouds from AMSU‐B water vapor channels measurements
Authors: Hong Gang , Heygster Georg , Miao Jungang , Kunzi Klaus
Published: March 2005

Methods to detect tropical deep convective clouds and convective overshooting from measurements at the three water vapor channels (183.3 ± 1, 183.3 ± 3, and 183.3 ± 7 GHz) of the Advanced Microwave Sounding Unit‐B (AMSU‐B) are presented. Thresholds for the brightness temperature differences between the three channels are suggested as criterion to detect deep convective clouds, and an order relation between the differences is used to detect convective overshooting. The procedure is based on an investigation of the influence of deep convective cloud systems on the microwave brightness temperatures at frequencies from 89 to 220 GHz using simultaneous aircraft microwave and radar measurements over two tropical deep convective cloud systems, taken during the Tropical Rainfall Measuring Mission (TRMM) Large Scale Biosphere‐Atmosphere Experiment (LBA) campaign. Two other aircraft cases with deep convective cloud systems observed during the Third Convection and Moisture Experiment (CAMEX‐3) are used to validate the criteria. Furthermore, a microwave radiative transfer model and simulated mature tropical squall line data derived from the Goddard Cumulus Ensemble (GCE) model are used to validate the procedures and to adapt the criteria to the varying viewing angle of AMSU‐B. These methods are employed to investigate the distributions of deep convective clouds and convective overshooting in the tropics (30°S to 30°N) for the four 3‐month seasons from March 2003 to February 2004 using the AMSU‐B data from NOAA‐15, ‐16, and ‐17. The distributions show a seasonal variability of shifting from the winter hemisphere to the summer hemisphere. The distributions of deep convective clouds follow the seasonal patterns of the surface rainfall rates. The deep convective clouds over land penetrate more frequently into the tropical tropopause layer than those over ocean. The averaged deep convective cloud fraction is about 0.3% in the tropics, and convective overshooting contributes about 26% to this.
Interplanetary sources of space weather disturbances in 1997 to 2000
Authors: Dmitriev A. V. , Crosby N. B. , Chao J.‐K.
Published: March 2005

Seventy‐five disturbed intervals from 1997 through 2000 were analyzed and selected on the basis of space weather effect occurrences such as significant compression of the dayside magnetosphere, strong magnetic storms, ionospheric perturbations, relativistic electron enhancements, and increases in the rate of data failures and radiation doses on board the Mir station. Solar wind disturbances were considered as the main factor influencing the Earth's magnetosphere. We distinguished four geoeffective interplanetary (IP) phenomena: interplanetary coronal mass ejections (ICME), interplanetary forward shocks with compressed region (IS), fast solar wind streams from coronal holes (CH), and corotating interaction regions (CIR) between the CH and relatively slow ambient solar wind. Each selected interval was studied and classified under the IP phenomena that it was a direct consequence of. It was found that IP phenomena “containing” ISs, ICMEs, and CIRs were mostly responsible for geosynchronous magnetopause crossings, strong geomagnetic storms, and intensification of geomagnetically induced currents. The fast solar wind streams from coronal holes controlled mainly geosynchronous relativistic electron enhancements. The rate of data failures and variations of the radiation dose on board the Mir station were related to both IS‐ICME and CIR‐CH phenomena. Such a relationship was interpreted in terms of (1) decrease of cutoff threshold for solar energetic particles due to the magnetospheric compression and/or ring current intensification on the main phase of geomagnetic storms and (2) intensive relativistic electron precipitation from the outer radiation belt and its contribution to the radiation conditions at low altitudes during recovery phase of recurrent magnetic storms.
Stochastic analysis of moisture plume dynamics of a field injection experiment
Authors: Ye Ming , Khaleel Raziuddin , Yeh Tian‐Chyi J.
Published: March 2005

A vadose zone field injection experiment was conducted in the summer of 2000 at the Hanford Site, Washington. The unique moisture content (θ) database is used to identify the lithology at the field site and to interpret, visualize, and quantify the spatiotemporal evolution of the three‐dimensional (3‐D) moisture plume created by the injection experiment. We conducted a hierarchical geostatistical analysis to examine the large‐scale geologic structure for the entire field site and then investigated small‐scale features within different layers. Afterward, variogram analysis was applied to the θ field measured for seven different days during the injection experiment. Temporal variations of sills and ranges are related to the observed moisture plume dynamics. A visualization of the 3‐D moisture plume evolution illustrates effects of media heterogeneity. Statistics of changes in moisture content as a function of distance reveal large variance near the wetting front; the coefficient of variation increases with decreasing mean. These findings support the gradient‐ and mean‐dependent variability in the moisture content distribution as reported by existing stochastic theories. Spatial moment analysis is also conducted to quantify the rate and direction of movement of the plume mass center and its spatial spreading. The ratio of horizontal to vertical spreading at varying moisture contents suggests moisture‐dependent anisotropy in effective unsaturated hydraulic conductivity, confirming existing stochastic theories. However, the principal directions of the spatial moments are found to vary as the moisture plume evolves through local heterogeneity, a feature that has not been recognized in the theories.
Daytime formation of nitrous acid: A major source of OH radicals in a forest
Authors: Kleffmann Jörg , Gavriloaiei Traian , Hofzumahaus Andreas , Holland Frank , Koppmann Ralf , Rupp Lutz , Schlosser Eric , Siese Manfred , Wahner Andreas
Published: March 2005

Daytime concentrations of HONO, NOx, OH and photolysis frequencies were measured during the ECHO field campaign in a mixed deciduous forest near Jülich, West‐Germany, in summer 2003. Midday measurements show clear evidence for a large, yet unexplained daytime source of HONO (∼500 pptv/h), which represents an important net source of OH radicals due to ongoing HONO photolysis. The evidence for a large HONO daytime source is for the first time completely constrained by measured parameters, needed to determine the daytime budget of HONO. The large contribution of 33% to the primary OH production during noon at the top of the forest canopy suggests that the unexplained source of HONO could have an important impact on the photochemical transformation of biogenically emitted volatile organic compounds (VOCs) by OH into partly oxidized VOCs and secondary organic aerosols during their release from forest regions into the troposphere.
Quantum kinematics of bosonic vortex loops
Authors: Goldin Gerald A. , Owczarek Robert , Sharp David H.
Published: March 2005

In the framework of geometric quantization, filaments of vorticity in a two-dimensional, ideal incompressible superfluid belong to certain coadjoint orbits of the group of area-preserving diffeomorphisms. The Poisson structure for such vortex strings is analyzed in detail. While the Lie algebra associated with area-preserving diffeomorphisms is noncanonical, we can nevertheless find canonical coordinates and their conjugate momenta that describe these systems. We then introduce a Fock-like space of quantum states for the simplest case of bosonic vortex loops, with natural, nonlocal creation and annihilation operators for the quantized vortex filaments.
Self-planarizing process for the fabrication of Bi2Sr2CaCu2Ox stacks
Authors: Ishida H. , Okanoue K. , Hamasaki K. , Shimakage H. , Wang Z.
Published: March 2005

We developed a new fabrication process for stacked intrinsic Josephson junctions using Bi2Sr2CaCu2Ox (Bi-2212) single crystals. For the fabrication of self-planarized stacks, the Bi-2212 around the stack was changed into an insulator by dipping it in a solution of dilute hydrochloric acid. For the solution concentration <0.2%, the planarization of the stack was fully achieved. For the concentration >0.5%, however, the planarization was spoiled. The current-voltage characteristic of the stacks showed distinct resistive branches with large hysteresis at 77K. The number of intrinsic junctions in the stacks linearly decreased with decreasing the concentration of the solution in the range from 0.05% to 0.2 %. The good controllability of the number of junctions in the self-planarized stacks may be useful for electronic device applications.
Influence of exchange bias coupling on the single-crystalline FeMn ultrathin film
Authors: Wang J. , Kuch W. , Chelaru L. I. , Offi F. , Kotsugi M.
Published: March 2005

Polarization dependent x-ray photoemission electron microscopy was used to investigate the influence of the exchange bias coupling on the disordered ultrathin single-crystalline fcc Fe50Mn50. We find that the critical thickness of the FeMn film, where the antiferromagnetic (AF) order is formed, varies with changing the magnetization direction of the ferromagnetic (FM) layer from out-of-plane to in-plane. Surface magneto-optical Kerr effect measurements (SMOKE) further manifest the shift of the critical thickness with alternating the exchange bias coupling. It indicates that the spin structure of the FeMn layer near the FM layer is modified by the presence of exchange bias coupling and the properties of the coupling. Our results provide direct experimental evidence that the AF spin structure at the interface between the FM and AF layers is strongly influenced by the exchange bias coupling.
Identification of vacancies in the ordered intermetallic compound B2–Ru46Al54
Authors: Partyka E. , Sprengel W. , Weigand H. , Schaefer H.-E. , Krogh F. , Kostorz G.
Published: March 2005

For the identification of vacant lattice sites in the high-temperature intermetallic compound Ru46Al54, positron lifetime measurements as well as coincident measurements of the two Doppler-broadened positron-electron annihilation photons have been employed. These data demonstrate that thermal vacancies are formed on the Ru metal sublattice similar to FeAl and NiAl where the thermal vacancies are also formed on the transition metal sublattice.
Transparent thin-film transistors with pentacene channel, AlOx gate, and NiOx electrodes
Authors: Choi Jeong-M. , Hwang D. K. , Kim Jae Hoon , Im Seongil
Published: March 2005

We report on the fabrication of pentacene-based transparent thin-film transistors (TTFT) that consist of NiOx, AlOx, and indium-tin-oxide (ITO) for the source-drain (S/D) electrode, gate dielectric, and gate electrode, respectively. The NiOx S/D electrodes of which the work function is well matched to that of pentacene were deposited on a 50-nm-thick pentacene channel by thermal evaporation of NiO powder and showed a moderately low but still effective transmittance of ∼25% in the visible range along with a good sheet resistance of ∼60Ω∕◻. The maximum saturation current of our pentacene-based TTFT was about 15μA at a gate bias of −40V showing a high field effect mobility of 0.9cm2∕Vs in the dark, and the on/off current ratio of our TTFT was about 5×105. It is concluded that jointly adopting NiOx for the S/D electrode and AlOx for gate dielectric realizes a high-quality pentacene-based TTFT.
Local conformational fluctuations can modulate the coupling between proton binding and global structural transitions in proteins
Authors: Whitten Steven T. , García-Moreno E. Bertrand , Hilser Vincent J.
Published: March 2005

Local conformational fluctuations in proteins can affect the coupling between ligand binding and global structural transitions. This finding was established by monitoring quantitatively how the population distribution in the ensemble of microstates of staphylococcal nuclease was affected by proton binding. Analysis of acid unfolding and proton-binding data with an ensemble-based model suggests that local fluctuations: (
i
) can be effective modulators of ligand-binding affinities, (
ii
) are important determinants of the cooperativity of ligand-driven global structural transitions, and (
iii
) are well represented thermodynamically as local unfolding processes. These studies illustrate how an ensemble-based description of proteins can be used to describe quantitatively the interdependence of local conformational fluctuations, ligand-binding processes, and global structural transitions. This level of understanding of the relationship between conformation, energy, and dynamics is required for a detailed mechanistic understanding of allostery, cooperativity, and other complex functional and regulatory properties of macromolecules.
Suppression of viral infectivity through lethal defection
Authors: Grande-Pérez Ana , Lázaro Ester , Lowenstein Pedro , Domingo Esteban , Manrubia Susanna C.
Published: March 2005

RNA viruses replicate with a very high error rate and give rise to heterogeneous, highly plastic populations able to adapt very rapidly to changing environments. Viral diseases are thus difficult to control because of the appearance of drug-resistant mutants, and it becomes essential to seek mechanisms able to force the extinction of the quasispecies before adaptation emerges. An alternative to the use of conventional drugs consists in increasing the replication error rate through the use of mutagens. Here, we report about persistent infections of lymphocytic choriomeningitis virus treated with fluorouracil, where a progressive debilitation of infectivity leading to eventual extinction occurs. The transition to extinction is accompanied by the production of large amounts of RNA, indicating that the replicative ability of the quasispecies is not strongly impaired by the mutagen. By means of experimental and theoretical approaches, we propose that a fraction of the RNA molecules synthesized can behave as a defective subpopulation able to drive the viable class extinct. Our results lead to the identification of two extinction pathways, one at high amounts of mutagen, where the quasispecies completely loses its ability to infect and replicate, and a second one, at lower amounts of mutagen, where replication continues while the infective class gets extinct because of the action of defectors. The results bear on a potential application of increased mutagenesis as an antiviral strategy in that low doses of a mutagenic agent may suffice to drive persistent virus to extinction.
Negotiating the regulation of the Structural Funds: Italian actors in EU regional policy-making
Authors: Brunazzo Marco , Piattoni Simona
Published: March 2005

The role of Italy in the reform process of the regulations concerning EU regional policy has traditionally been weak. Since 1998, however, Italian actors in Brussels started to play an increasingly more central role. Looking at the 1998 Regulation, we analyse the internal and external factors that explain this improved performance and conclude that this change might lead to an even more active and creative role being adopted by Italian institutional actors in the current negotiations which will lead to the reform of the regulation of the Structural Funds for 2007–13.
Italy and the EU's environment and consumer policies: coalition-building, problem framing and informal channels of influence
Authors: Sicurelli Daniela
Published: March 2005

Although it is considered among the ‘environmental laggard’ states of the Union, Italy proved able to perform a crucial role in the promotion of one of the basic principles of EU environmental and consumer policy, namely the precautionary principle. The Italian government was influential in promoting this principle in EU food safety policy, in particular in a 2000 Directive on genetically modified organisms. This picture is certainly not one-sided, as the weakness of the Italian government in influencing EU decision-makers in the case of the 2001 Cocoa Directive shows. The main factors that explain when Italy matters in the EU environmental and consumer policy process are the way interests are aggregated, the way the problem is framed and the types of channels exploited to affect the policy process.
Prevalence of genosubtypes (PorA types) of serogroup B invasive meningococcus in the north of Spain from 2000 to 2003
Authors: Vicente Diego , Esnal Olatz , Michaus Lourdes , López de Goicoechea Maria José , Cisterna Ramón , Pérez-Trallero Emilio
Published: March 2005

The composition of new vaccines against Neisseria meningitidis serogroup B is based on differences in the variable regions VR1 and VR2 of the class 1 outer-membrane protein (PorA) of meningococci. Genosubtyping of 96 N. meningitidis B isolates from blood or cerebrospinal fluid from 2000 to 2003 in the north of Spain allowed characterization of all the strains. Twenty-six genosubtypes or distinct PorA types were obtained. The most prevalent were P1.5-1, 10-8 (20 strains), P1.19, 15 (14 strains), P1.22, 9 (11 strains) and P1.5, 2 (nine strains), while 17 genosubtypes were represented by only one or two strains. The wide diversity of genosubtypes observed and their differences compared with those found in other regions reveals the difficulty in designing a useful outer-membrane vesicle vaccine applicable to different regions of the world.
In vitro assessment of the APTIMA Combo 2 assay for the detection of Chlamydia trachomatis using highly purified elementary bodies
Authors: Ikeda-Dantsuji Yurika , Konomi Ichiro , Nagayama Ariaki
Published: March 2005

The Gen-Probe APTIMA Combo 2 assay has previously been reported to have a high sensitivity. The end point of this assay was evaluated using highly purified chlamydial elementary bodies (EBs). The performance of the APTIMA Combo 2 assay was compared with a commercially available PCR kit, AMPLICOR Chlamydia trachomatis. The number of inclusions of C. trachomatis at the end point of the APTIMA Combo 2 assay was 0.005 inclusion-forming units (i.f.u.) ml−1, which was equivalent to 0.008 EBs per assay. The end point of the AMPLICOR kit was 5 i.f.u. ml−1 (equivalent to 0.5 EB per assay). The efficacy of the AMPLICOR C. trachomatis assay was inhibited by phosphate or Fe2+ ion, while these had no effect on the APTIMA Combo 2 assay. In conclusion, the APTIMA Combo 2 assay appears to have a greater sensitivity than the AMPLICOR C. trachomatis assay for detection of C. trachomatis, while demonstrating few problems with inhibitory substances such as phosphate and Fe2+ ion.