bluuebunny/crossref_metadata_2025 huggingface dataset:
GP130/OSMR is the only LIF/IL‐6 family receptor complex to promote osteoblast differentiation of calvaria progenitors
Authors: Malaval Luc , Liu Fina , Vernallis Ann B. , Aubin Jane E.
Published: March 2005

Leukemia inhibitory factor (LIF) and its receptor (LIFR) are “twins” of Oncostatin M (OSM) and OSMR, respectively, likely having arisen through gene duplications. We compared their effects in a bone nodule‐forming model of in vitro osteogenesis, rat calvaria (RC) cell cultures. Using a dominant‐negative LIF mutant (hLIF‐05), we showed that in RC cell cultures mouse OSM (mOSM) activates exclusively glycoprotein 130 (gp130)/OSMR. In treatments starting at early nodule formation stage, LIF, mOSM, IL‐11, and IL‐6 + sIL‐6R inhibit bone nodule formation, that is, osteoprogenitor differentiation. Treatment with mOSM, and no other cytokine of the family, in early cultures (day 1–3 or 1–4) increases bone colony numbers. hLIF‐05 also dose dependently stimulates bone nodule formation, confirming the inhibitory action of gp130/LIFR on osteogenesis. In pulse treatments at successive stages of bone nodule formation and maturation, LIF blocks osteocalcin (OCN) expression by differentiated osteoblasts, but has no effect on bone sialoprotein (BSP) expression. Mouse OSM inhibits OCN and BSP expression in preconfluent cultures with no or progressively reduced effects at later stages, reflecting the disruption of early nodules, possibly due to the strong apoptotic action of mOSM in RC cell cultures. In summary, LIFR and OSMR display differential effects on differentiation and phenotypic expression of osteogenic cells, most likely through different signal transduction pathways. In particular, gp130/OSMR is the only receptor complex of the family to stimulate osteoprogenitor differentiation in the RC cell culture model. © 2005 Wiley‐Liss, Inc.
Activation of MAP kinase by muscarinic cholinergic receptors induces cell proliferation and protein synthesis in human breast cancer cells
Authors: Jiménez Eugenio , Montiel Mercedes
Published: March 2005

Carbachol (Cch), a muscarinic acetylcholine receptor (mAChR) agonist, increases intracellular‐free Ca2+ mobilization and induces mitogen‐activated protein kinase/extracellular signal‐regulated kinase (MAPK/ERK) phosphorylation in MCF‐7 human breast cancer cells. Pretreatment of cells with the selective phospholipase C (PLC) inhibitor U73122, or incubation of cells in a Ca2+‐free medium did not alter Cch‐stimulated MAPK/ERK phosphorylation. Phosphorylation of MAPK/ERK was mimicked by phorbol 12‐myristate acetate (PMA), an activator of protein kinase C (PKC), but Cch‐evoked MAPK/ERK activation was unaffected by down‐regulation of PKC or by pretreatment of cells with GF109203X, a PKC inhibitor. However, Cch‐stimulated MAPK/ERK phosphorylation was completely blocked by myristoylated PKC‐ζ pseudosubstrate, a specific inhibitor of PKC‐ζ, and high doses of staurosporine. Pretreatment of human breast cancer cells with wortmannin or LY294002, selective inhibitors of phosphoinositide 3‐kinase (PI3K), diminished Cch‐mediated MAPK/ERK phosphorylation. Similar results were observed when MCF‐7 cells were pretreated with genistein, a non‐selective inhibitor of tyrosine kinases, or with the specific Src tyrosine kinase inhibitor PP2. Moreover, in MCF‐7 human breast cancer cells mAChR stimulation induced an increase of protein synthesis and cell proliferation, and these effects were prevented by PD098059, a specific inhibitor of the mitogen activated kinase kinase. In conclusion, analyses of mAChR downstream effectors reveal that PKC‐ζ, PI3K, and Src family of tyrosine kinases, but not intracellular‐free Ca2+ mobilization or conventional and novel PKC activation, are key molecules in the signal cascade leading to MAPK/ERK activation. In addition, MAPK/ERK are involved in the regulation of growth and proliferation of MCF‐7 human breast cancer cells. © 2005 Wiley‐Liss, Inc.
Antioxidant and micronutrient quality of fruit and root vegetables from the Indian subcontinent and their comparative performance with green leafy vegetables and fruits
Authors: Tarwadi Kirtan , Agte Vaishali
Published: March 2005

Commonly consumed, fruit vegetables (12) and root vegetables (15) in the Indian subcontinent in cooked and uncooked states assessed for inhibition of thiobarbituric acid reactive substances (TBARS), superoxide radical scavenging activity (SOSA), ferrous iron chelating ability (FICA) and nine micronutrients, exhibited large variability in these parameters. SOSA and FICA were significantly associated (r = 0.803, p < 0.001) with each other. Inhibition of TBARS showed marginal correlation with both FICA (0.38, p < 0.05) and SOSA (0.29, p > 0.05). There were significant cooking losses for each of the assessed antioxidant capacity parameters (p < 0.05). Contents of ascorbic acid, per 100 g of cooked fruit and root vegetables were high (61.9 and 31.3% of recommended daily allowance (RDA)). However, both the food classes were not good sources of beta‐carotene, riboflavin and thiamine (1.66–5.26% RDA). When compared with our data on 30 cooked green leafy vegetables (GLV) and 30 fresh fruits, root vegetables showed significantly (p < 0.05) higher levels of zinc and selenium. Cooked root vegetables were comparable with cooked GLVs but uncooked GLVs gave the highest values for inhibition of TBARS (0.73 ± 0.21 mM vitamin E/100g). SOSA (40.7 ± 15.6 mM tannic acid/100g) and FICA (41.6 ± 14.9 mM EDTA/100g) were highest for uncooked fruit vegetables. Root vegetables had the highest levels of polyphenols (251.4 ± 107.3 mg/100g). For the present study, popular fruits and vegetables such as guava, spinach, bitter gourd (Momordica charantia), yam, ginger and beetroot, and also less common ones like bael (Aegle marmelos), kokum (Garcinia indica) and mango‐ginger (Curcuma ameda), showed potential in vitro to combat oxidative stress. Copyright © 2005 Society of Chemical Industry
Protein digestibility‐corrected amino acid scores, acceptability and storage stability of ready‐to‐eat supplementary foods for pre‐school age children in Tanzania
Authors: Mosha Theobald CE , Bennink Maurice R
Published: March 2005

This study was conducted to evaluate protein quality, acceptability and storage stability of processed cereal–bean–sardine composite foods for pre‐school age children in Tanzania. Four composite products namely corn–bean–sardine meal (CBSM), bean meal (BM), sorghum–bean–sardine meal (SBSM) and rice–bean–sardine meal (RBSM) were formulated to maximize the amino acid score for pre‐school age children and were processed by extrusion, drum‐processing and conventional cooking. The products were evaluated for true protein digestibility (TPD) and protein digestibility‐corrected amino acid score (PDCAAS). The TPD and PDCAAS were highest in the extruded products. The TPD values for the products ranged from 82 to 93%. The PDCAAS values for the composite foods were 64–86% and were greater than the minimum value of 60% recommended by FAO/WHO/UNU. There were no significant (p > 0.05) variations in the amino acid contents for foods processed by extrusion, drum‐processing or conventional cooking. Threonine was most limiting in the CBSM, SBSM and RBSM while methionine + cysteine were most limiting in the BM. Sensory evaluation showed that, relative to the traditional cornmeal—Uji, the extruded CBSM and SBSM had significantly superior (p ≤ 0.05) texture and highly acceptable color and taste. Storage of the products up to 16 weeks at 38 °C resulted in a small but significant increase (p ≤ 0.05) in the malondialdehyde concentrations; nevertheless, the levels remained within the acceptable range found in processed commercial supplements. Total acids, pH and organoleptic attributes did not change significantly (p > 0.05) during storage and the foods were acceptable to the end of the storage period. Copyright © 2005 Society of Chemical Industry
European Union accession: passport to development for the Hungarian tourism industry?
Authors: Szivás Edith
Published: March 2005

This paper presents a discussion of how the Hungarian tourism industry is likely to experience European Union (EU) enlargement. The post‐socialist period laid the foundations for systematic tourism commodification and consumption, with notable progress. Set in an extended historical context, accession represents another important milestone in a protracted series of ‘gradual ’ reforms shaping the long‐term trajectory of tourism development. The Hungarian tourism industry, similar to the rest of the economy, inevitably will be affected but change is expected to be incremental and associated with initiatives on regional development, air transport liberalisation, cross‐border co‐operation and increasing use of EU funds, all of which have been enacted before the date of accession. Copyright © 2005 John Wiley & Sons, Ltd.
Levodopa‐responsive infantile parkinsonism due to a novel mutation in the tyrosine hydroxylase gene and exacerbation by viral infections
Authors: Diepold Katharina , Schütz Barbara , Rostasy Kevin , Wilken Bernd , Hougaard Pia , Güttler Flemming , Romstad Anne , Birk Møller Lisbeth
Published: March 2005

Autosomal recessive forms of infantile dystonia due to mutations in the tyrosine hydroxylase (TH) gene have been described recently. The main clinical manifestations are Segawa's disease, or infantile hypokinetic rigid Parkinsonism. Here, we report on a patient with hyperrigidity, psychomotor developmental delay, and dystonic posturing of the hands, symptoms that appeared after a viral infection at the age of 14 months. Low homovanillic acid/5‐hydroxyindolacetic acid (HVA/5HIAA) ratio in cerebrospinal fluid suggested a TH deficiency. Molecular analysis revealed a novel (H246Y) and a known (D498G) compound heterozygote mutation in the TH gene. The patient showed a remarkable response to treatment with levodopa. The new mutation and the association of viral infections with the onset and worsening of symptoms are discussed. © 2005 Movement Disorder Society
Pilot study of the feasibility of in‐office bladder distention using electromotive drug adminstration (EMDA)
Authors: Rose Amy E. , Payne Christopher K. , Azevedo Kathryn
Published: March 2005

Purpose

Cystoscopic bladder distention is an important tool in the diagnosis and treatment of interstitial cystitis (IC). We investigated the feasibility of performing bladder distention in the office using two different anesthetic strategies: simple instillation of alkalized lidocaine and electromotive drug administration (EMDA) of lidocaine.

Materials and Methods

Patients presenting with urinary frequency, urgency, and bladder pain were recruited for an office evaluation protocol which included bladder distention under local anesthesia. An initial group of 10 patients underwent bladder distention after instillation of 5 mg/kg alkalized lidocaine. A second group of 11 patients had lidocaine EMDA anesthesia prior to distention.

Results

In the alkaxlized lidocaine group, 6 of the 10 distentions were aborted after less than 5 minutes at only 40 cm H2O. In the EMDA group, 7 of 11 of the distentions were completed using 60 cm H2O for 7 minutes. EMDA afforded a more effective distention as manifest by a greater percent increase in distention capacity over cystometric capacity compared to alkalized lidocaine (135% vs. 70%). Despite the lower pressure used in the alkalized lidocaine group, the median distention time was only 3 minutes compared to 7 minutes using EMDA.

Conclusions

These results represent the first study of the efficacy of EMDA as local anesthesia for bladder distention compared to another method of anesthesia. Lidocaine EMDA is superior to alkalized lidocaine in that it allows for a greater distention of the bladder for a longer period of time but does not eliminate the pain of bladder distention. © 2005 Wiley‐Liss, Inc.
Convergence of Galerkin approximations for the Kuramoto‐Tsuzuki equation
Authors: Omrani Khaled
Published: March 2005

Standard Galerkin approximations, using smooth splines to solutions of the Kuramoto‐Tsuzuki equation are analyzed. The existence, uniqueness, and convergence of the fully discrete Crank‐Nicolson scheme are discussed. Furthermore, a second‐order convergent linearized Galerkin approximation are derived. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 21, 2005
Role of exercise in rehabilitation of cancer survivors
Authors: Braith Randy W.
Published: March 2005

Approximately 70% of all children diagnosed with malignancy become long‐term survivors. Anthracycline cardiotoxicity may complicate physical performance and invite a “spectrum of disuse.” There is a paucity of information derived from longitudinal, prospective, randomized clinical trials of exercise in cancer survivors, and there are no guidelines concerning the risk of recreational (non‐competetive) exercise in adolescent and young adult patients with anthracycline cardiomyopathy. This review will discuss screening procedures that should be performed when assigning exercise regimens to cancer survivors with or without evidence of left ventricular dysfunction. Current recommendations for exercise testing and exercise prescription are also provided. Pediatr Blood Cancer 2005;44:595–599. © 2005 Wiley‐Liss, Inc.
Studies on cellulose acetate–polysulfone ultrafiltration membranes: I. Effect of polymer composition
Authors: Sivakumar Muthusamy , Mohan Doraisamy Raju , Rangarajan Ramamoorthy , Tsujita Yoshiharu
Published: March 2005

Ultrafiltration techniques have particular advantages for simultaneous purification, concentration and fractionation of macromolecules. Studies are presented on novel ultrafiltration membranes, based on cellulose acetate and polysulfone blends, for the separation of proteins and heavy metal ions. The effects of polymer composition on pure water flux, water content, molecular weight cut‐off and hydraulic resistance are discussed. Scanning electron microscopy images of the membranes show the presence of segregated individual domains of cellulose acetate and polysulfone. The molecular weight cut‐off obtained from the protein separation studies is also presented. Applications of these membranes for separating metal ions from aqueous streams are discussed. Copyright © 2005 Society of Chemical Industry
Polyurethane–nanosilica hybrid nanocomposites synthesized by frontal polymerization
Authors: Chen Su , Sui Jianjun , Chen Li , Pojman John A.
Published: March 2005

Polyurethane–nanosilica hybrids were synthesized with frontal polymerization. Structurally well‐dispersed and stable hybrids were obtained via a two‐step functionalization process: First, the silica was encapsulated with 3‐aminopropyltriethoxysilane (APTS). Second, poly(propylene oxide) glycol, toluene 2,4‐diisocyanate, 1,4‐butanediol, and a catalyst (stannous caprylate) were dissolved in dimethylbenzene and mixed together at room temperature along with the modified nanosilica. A constant‐velocity propagating front was initiated via the heating of the end of the tubular reactor. For the complete encapsulation of the silica with APTS, different weight ratios of APTS to silica were investigated. The polyurethane hybrids were characterized with Fourier transform infrared, differential scanning calorimetry, and transmission electron microscopy. The polyurethane hybrids produced by frontal polymerization had the same properties as those produced by batch polymerization with stirring, but the frontal polymerization method required significantly less time and lower energy input than the batch polymerization method. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1670–1680, 2005
Full wafer size investigation of N+ and P+ co‐implanted layers in 4H–SiC
Authors: Blanqué S. , Lyonnet J. , Pérez R. , Terziyska P. , Contreras S. , Godignon P. , Mestres N. , Pascual J. , Camassel J.
Published: March 2005

We report a full wafer size investigation of the homogeneity of electrical properties in the case of co‐implanted nitrogen and phosphorus ions in 4H–SiC semi‐insulating wafers. To match standard industrial requirements, implantation was done at room temperature. To achieve a detailed electrical knowledge, we worked on a 35 mm wafer on which 77 different reticules have been processed. Every reticule includes one Hall cross, one Van der Pauw test structure and different TLM patterns. Hall measurements have been made on all 77 different reticules, using an Accent HL5500 Hall System® from BioRad fitted with an home‐made support to collect data from room temperature down to about 150 K. At room temperature, we find that the sheet carrier concentration is only 1/4 of the total implanted dose while the average mobility is 80.6 cm2/Vs. The standard deviation is, typically, 1.5 cm2/Vs. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multiple‐mutation at a potential ligand‐binding region decreased allergenicity of a mite allergen Der f 2 without disrupting global structure
Authors: Nakazawa Takuya , Takai Toshiro , Hatanaka Hideki , Mizuuchi Eri , Nagamune Teruyuki , Okumura Ko , Ogawa Hideoki
Published: March 2005

We assessed the effect of multiple‐mutations within one IgE‐binding area on allergenicity of Der f 2. The triple‐mutant of Der f 2, P34/95/99A, exhibited the most significant reduction of allergenicity and circular dichroism analysis showed that the global structure of Der f 2 was maintained in P34/95/99A. These results indicate that such a strategy is effective when designing allergen‐vaccines, which achieve less allergenicity for a broad population of patients without disrupting the global structure. Structurally, Der f 2 is a member of the MD‐2 related lipid‐recognition proteins. The sites for the triple‐mutation located on the characteristically charged entrance of a cavity and corresponded to the regions critical to ligand‐binding in the Niemann‐Pick type 2 disease protein and MD‐2.
The utility of the temporalis muscle flap for oropharyngeal, base of tongue, and nasopharyngeal reconstruction
Authors: Smith Jesse E. , Ducic Yadranko , Adelson Robert
Published: March 2005

OBJECTIVE

To determine the efficacy of temporalis muscle flap reconstruction of various defects of the oropharynx, nasopharynx, and base of tongue.

STUDY DESIGN

Retrospective chart review of a consecutive series of 24 patients who underwent a total of 26 temporalis flaps (2 bilateral) by the senior author (Y.D.) from September 1997 to August 2003 for reconstruction of defects of the oropharynx, nasopharynx, and base of tongue.

METHODS

Variables and outcomes that were examined included defect location, size, adjunctive therapy, complications, and ability to tolerate oral intake at follow‐up.

RESULTS

There was no evidence of flap failure in our series of patients. There were 2 cases of minor flap loss related to early prosthetic rehabilitation. Two cases of transient frontal nerve paralysis were noted. A 30.8% rate of complication (all minor) was noted in this study. At a mean follow‐up of 12 months, 54.2% of patients were tolerating a full diet, 37.5% were tolerating most of their nutrition by mouth, and 8.3% were g‐tube dependent.

CONCLUSION

The temporalis muscle flap represents an excellent alternative in reconstruction of otherwise difficult‐to‐reconstruct defects of the nasopharynx, oropharynx, and base of tongue. Donor site aesthetics are well accepted by patients with primary hydroxyapatite cement cranioplasty with or without secondary lipotransfer.
Magmatic effects of the Cobb hot spot on the Juan de Fuca Ridge
Authors: Chadwick John , Perfit Michael , Ridley Ian , Jonasson Ian , Kamenov George , Chadwick William , Embley Robert , le Roux Petrus , Smith Matthew
Published: March 2005

The interaction of the Juan de Fuca Ridge with the Cobb hot spot has had a considerable influence on the magmatism of the Axial Segment of the ridge, the second‐order segment that overlies the hot spot. In addition to the construction of the large volcanic edifice of Axial Seamount, the Axial Segment has shallow bathymetry and a prevalence of constructional volcanic features along its 100‐km length, suggesting that hot spot–derived magmas supplement and oversupply the ridge. Lavas are generally more primitive at Axial Seamount and more evolved in the Axial Segment rift zones, suggesting that fractional crystallization is enhanced with increasing distance from the hot spot because of a reduced magma supply and more rapid cooling. Although the Cobb hot spot is not an isotopically enriched plume, it produces lavas with some distinct geochemical characteristics relative to normal mid‐ocean ridge basalt, such as enrichments in alkalis and highly incompatible trace elements, that can be used as tracers to identify the presence and prevalence of the hot spot influence along the ridge. These characteristics are most prominent at Axial Seamount and decline in gradients along the Axial Segment. The physical model that can best explain the geochemical observations is a scenario in which hot spot and mid‐ocean ridge basalt (MORB) magmas mix to varying degrees, with the proportions controlled by the depth to the MORB source. Modeling of two‐component mixing suggests that MORB is the dominant component in most Axial Segment basalts.
Atlantic versus Indo‐Pacific influence on Atlantic‐European climate
Authors: Pohlmann Holger , Latif Mojib
Published: March 2005

The influence of the Atlantic and Indo‐Pacific oceans on Atlantic‐European climate is investigated by analyzing ensemble integrations with the atmospheric general circulation model ECHAM4 forced by anomalous sea surface temperature and sea ice conditions restricted to the Atlantic (AOGA) and Indo‐Pacific (I+POGA) oceans. The forcing from both the Indo‐Pacific and Atlantic oceans are important for the generation of the sea level pressure (SLP) variability in the Atlantic region in the boreal winter season. Over the North Atlantic the SLP response in the I+POGA experiment projects on the North Atlantic Oscillation, while it projects on the East Atlantic Pattern in the AOGA experiment. In both experiments (I+POGA and AOGA) a quadrupole‐type 500 hPa height anomaly pattern is simulated which emerges from the tropical Pacific and Atlantic oceans, respectively. In boreal summer the influence of the Atlantic Ocean dominates the SLP response in the Atlantic region. The tropical North Atlantic is a key region in forcing the SLP response over the Caribbean Sea in this season.
Numerical simulation of lava flows based on depth‐averaged equations
Authors: Costa Antonio , Macedonio Giovanni
Published: March 2005

Risks and damages associated with lava flows propagation (for instance the most recent Etna eruptions) require a quantitative description of this phenomenon and a reliable forecasting of lava flow paths. Due to the high complexity of these processes, numerical solution of the complete conservation equations for real lava flows is often practically impossible. To overcome the computational difficulties, simplified models are usually adopted, including 1‐D models and cellular automata. In this work we propose a simplified 2D model based on the conservation equations for lava thickness and depth‐averaged velocities and temperature which result in first order partial differential equations. The proposed approach represents a good compromise between the full 3‐D description and the need to decrease the computational time. The method was satisfactorily applied to reproduce some analytical solutions and to simulate a real lava flow event occurred during the 1991–93 Etna eruption.
Dike intrusions beneath grabens south of Arsia Mons, Mars
Authors: Goudy Cheryl L. , Schultz Richard A.
Published: March 2005

The existence of igneous dikes beneath grabens in Tharsis remains contentious due to conflicting observations of Martian geomorphology. We examine the topographic signatures of a Tharsis‐radial graben array in 3 zones south of Arsia Mons. We identify dikes beneath grabens in all of the zones, with fewer dike‐induced grabens closer to Arsia Mons. We infer that a single radial swarm of dikes outside the magmatic source area, central Tharsis, is unlikely. Our observations instead favor a long and varied magmatic history throughout Tharsis with several episodes of dike injection.
Statistical compartmentalization of surface wind field over coastal seas using high‐resolution SAR‐derived winds
Authors: Shimada Teruhisa , Kawamura Hiroshi
Published: March 2005

We present a compartmentalization of ocean surface wind in coastal seas by analyzing statistical features of high‐resolution wind measurements derived from Synthetic Aperture Radar (SAR) onboard European Remote sensing Satellite (ERS) −1/2. Probability distributions of wind speeds over land and sea, to which two‐parameter Weibull distribution gives a good fit, are classified in a feature space of two Weibull parameters. As a result, we identify three distinguished clusters, which feature variability of wind over land, open ocean, and coastal sea. The typical wind speed distribution assigned to coastal sea has both characteristics of those assigned to land and open ocean, i.e., peak frequency in the lower wind and higher frequencies in higher wind speeds. Moreover, it can be reproduced by mixing the typical wind‐speed distributions of land and open ocean at a given rate.
Multiple sounding rocket observations of charged dust in the polar winter mesosphere
Authors: Lynch K. A. , Gelinas L. J. , Kelley M. C. , Collins R. L. , Widholm M. , Rau D. , MacDonald E. , Liu Y. , Ulwick J. , Mace P.
Published: March 2005

We present data from a winter 2002 sounding rocket campaign for multiple observations of mesospheric charged dust. The campaign consisted of four identically instrumented payloads carrying detectors for charged mesospheric dust particles. The payloads reached an altitude of 100 km in the nighttime mesosphere and were flown from Poker Flat Research Range, Alaska, in conjunction with observations by the UAF sodium and iron resonance lidar system. Three of the four flights flew in sequence during the course of one night to study the temporal evolution of dust layers. Observations show good correlations between structure seen in the charged dust altitude profile, structure seen in the neutral metal layers observed by the lidars, and structure in the plasma density seen by the onboard Langmuir probes. The dust detector is sensitive to positively and negatively charged dust particles with ram energies of 1 to 11 eV for negatively and 3–11 eV for positively charged dust; that is, particles of approximately 5000 amu. The charged dust densities seen (estimated to be approximately 5 to 10 percent of the total dust density) are approximately 100 particles per cc, and the dust is negatively charged. Variations in the dust density of about 10% are seen in conjunction with structure in the plasma density and with the neutral metal layers. In this paper we present the details of the dust data and instrumentation; a companion paper explores the implications of the correlations seen between the dust and other mesospheric layers.
Combined acceleration of electrons by whistler‐mode and compressional ULF turbulences near the geosynchronous orbit
Authors: Li Liuyuan , Cao Jinbin , Zhou Guocheng
Published: March 2005

In the quasi‐linear approximation, we study electron acceleration process generated by whistler‐mode and compressional ULF (fast mode waves) turbulences near the Earth's synchronous orbit. The results show that the whistler‐mode turbulence (0.1fce ≤ f ≤ 0.75fce) can accelerate substorm injection electrons with several hundreds of keV through wave‐particle gyroresonant interaction and hence may play an important role in the electron acceleration during substorms. The compressional ULF turbulence (2–15 mHz) can accelerate both lower‐energy background electrons (<30 keV) and substorm injection electrons (∼30–300 keV) through the transit‐time damping mechanism. So the compressional ULF turbulence acceleration mechanism is important during both substorms and quiet times. The compressional ULF turbulence accelerates substorm injection electrons more effectively than whistler‐mode turbulence. The combined electron acceleration by whistler‐mode and ULF turbulences is most effective and can cause the number density of the relativistic electrons increase largely within about 8 hours. Substorms can offer both substorm injection electrons and strong turbulences, and therefore large flux enhancement events of relativistic electrons (≥1 MeV) always occur during substorm time. For magnetic storms that are composed of a series of substorms, extremely large flux enhancement events of the relativistic electrons can thus occur.
Tectonic plate generation and two‐phase damage: Void growth versus grain size reduction
Authors: Bercovici David , Ricard Yanick
Published: March 2005

The generation of plate tectonics from mantle convection requires shear localization in order to yield narrow, weak plate boundaries separating broad strong plates. A plausible shear‐localizing mechanism involves damage (e.g., distributed microcracking), one theoretical model of which involves two‐phase mechanics. Two‐phase damage theory employs a nonequilibrium relation between interfacial surface energy, pressure, and viscous deformation, thereby providing a description of void generation and microcracking, and hence weakening, failure, and shear localization. Here we examine the application of this theory to the problem of generating plate‐like behavior from convective‐type divergent/convergent (poloidal) motion through a source‐sink formulation. We extend the previous damage theory to consider two possible damage effects: (1) growth and nucleation of voids associated with dilation of the host matrix and (2) increasing fineness (i.e., reducing coarseness) of the mixture by, for example, grain size reduction. Void‐generating damage is found to be poor at plate generation because of the predominance of dilational motion that is adverse to the development of plate‐like flow. Fineness‐generating damage is found to be very efficient at generating plate‐like behavior if we assume that the matrix viscosity is a simple function of grain/void size, as is typical for diffusion creep. The implied grain size reduction mechanism is different from that of dynamic recrystallization and appears to be more capable of generating the requisite shear localization for forming tectonic plates from mantle flow.
Detecting fluid signals in seismicity data through statistical earthquake modeling
Authors: Hainzl Sebastian , Ogata Yosihiko
Published: March 2005

According to the well‐known Coulomb failure criterion the variation of either stress or pore pressure can result in earthquake rupture. Aftershock sequences characterized by the Omori law are often assumed to be the consequence of varying stress, whereas earthquake swarms are thought to be triggered by fluid intrusions. The role of stress triggering can be analyzed by modeling solely three‐dimensional (3‐D) elastic stress changes in the crust, but fluid flows which initiate seismicity cannot be investigated without considering complex seismicity patterns resulting from both pore pressure variations and earthquake‐connected stress field changes. We show that the epidemic‐type aftershock sequence (ETAS) model is an appropriate tool to extract the primary fluid signal from such complex seismicity patterns. We analyze a large earthquake swarm that occurred in 2000 in Vogtland/NW Bohemia, central Europe. By fitting the stochastic ETAS model, we find that stress triggering is dominant in creating the observed seismicity patterns and explains the observed fractal interevent time distribution. External forcing, identified with pore pressure changes due to fluid intrusion, is found to directly trigger only a few percent of the total activity. However, temporal deconvolution indicates that a pronounced fluid signal initiated the swarm. These results are confirmed by our analogous investigation of model simulations in which earthquakes are triggered by fluid intrusion as well as stress transfers on a fault plane embedded in a 3‐D elastic half‐space. The deconvolution procedure based on the ETAS model is able to reveal the underlying pore pressure variations.
Impact of Atlantic sea surface temperatures on the warmest global surface air temperature of 1998
Authors: Lu Riyu
Published: March 2005

The year 1998 is the warmest year in the record of instrumental measurements. In this study, an atmospheric general circulation model is used to investigate the role of sea surface temperatures (SSTs) in this warmth, with a focus on the role of the Atlantic Ocean. The model forced with the observed global SSTs captures the main features of land surface air temperature anomalies in 1998. A sensitivity experiment shows that in comparison with the global SST anomalies, the Atlantic SST anomalies can explain 35% of the global mean surface air temperature (GMAT) anomaly, and 57% of the land surface air temperature anomaly in 1998. The mechanisms through which the Atlantic Ocean influences the GMAT are likely different from season to season. Possible detailed mechanisms involve the impact of SST anomalies on local convection in the tropical Atlantic region, the consequent excitation of a Rossby wave response that propagates into the North Atlantic and the Eurasian continent in winter and spring, and the consequent changes in tropical Walker circulation in summer and autumn that induce changes in convection over the tropical Pacific. This in turn affects climate in Asia and Australia. The important role of the Atlantic Ocean suggests that attention should be paid not only to the tropical Pacific Ocean, but also to the tropical Atlantic Ocean in understanding the GMAT variability and its predictability.
An improved derivation of the top‐of‐atmosphere albedo from POLDER/ADEOS‐2: Narrowband albedos
Authors: Buriez Jean‐Claude , Parol Frédéric , Cornet Céline , Doutriaux‐Boucher Marie
Published: March 2005

The Polarization and Directionality of Earth Reflectances (POLDER) instrument was routinely functioning aboard the second Advanced Earth Observing Satellite (ADEOS‐2) from April to October 2003. A series of algorithms dedicated to Earth radiation budget, water vapor, and clouds are applied to the POLDER data. This paper presents the derivation scheme of the narrowband albedos at the top of the atmosphere from POLDER measurements at 443, 670, and 865 nm. These narrowband albedos are used to estimate the broadband shortwave albedo at the top of atmosphere in a companion paper. Here we focus on the 670 nm (over land)/865 nm (over ocean) albedo. Although our derivation is based on the plane‐parallel hypothesis, and thanks to the multidirectional capability of POLDER, results appear reliable for both cloudy and clear‐sky scenes. A quality index is introduced from the comparison between the angular variability of the retrieved “directional” albedo values and that of the measured reflectances. This quality index is “good” in 80% of the cases. Moreover, the retrieved albedo values are found to be statistically little dependent on the viewing direction.
Poludnista Dorsa, Venus: History and context of a deformation belt
Authors: Young D. A. , Hansen V. L.
Published: March 2005

Rolling lowlands comprise 80% of Venus's surface, and thus developing a geological understating of resurfacing and tectonism is critical for our understanding of Venus' evolution. In this paper, global, regional, and local approaches to interpreting Magellan synthetic aperture radar and altimetry radar data are used to constrain modes of lowland evolution, convection processes, and lithospheric structure. Detailed geologic mapping is combined with altimetry data test models of deformation belt evolution in Venus's lowlands. Poludnista Dorsa, a complex 2000‐km‐long deformation belt, is highly segmented and broadly time transgressive. Long‐wavelength deformation is spatially independent of local short‐wavelength deformation within the deformation belt and temporally predates regional deformation marked by wrinkle ridges. A mechanically layered lithosphere of regional extent is not required by the local geologic history; local lithospheric thinning or progressive regional thickening of the mechanical layer better explains the observed sequence of events.
Multiobjective calibration with Pareto preference ordering: An application to rainfall‐runoff model calibration
Authors: Khu Soon Thiam , Madsen Henrik
Published: March 2005

Automatic calibration routines for hydrologic models with multiple objective capabilities are becoming increasingly popular due to advances in computational power, population‐based optimization techniques, and the recognition that a single performance measure such as the root‐mean‐square error is no longer sufficient to characterize the complex behavior of the catchment. However, as more objective functions are included in the calibration, the number of Pareto‐optimal solutions as well as the number of “near” Pareto‐optimal parameter sets increases. The calibration problem quickly becomes a decision‐making problem. In the practical sense, users of automatic calibration routines have to face the task of selecting a set of suitable model parameters from the numerous Pareto‐optimal sets. A new method of automatic calibration is proposed, which combines an effective optimization routine, based on multiobjective genetic algorithms, and Pareto preference ordering. In this case, Pareto‐optimal points that are also Pareto‐optimal in different subspace combinations of the objective functions space are preferred. The proposed method is used to calibrate the MIKE11/NAM rainfall‐runoff model for a Danish catchment. The results indicated that the method is able to sieve through the numerous Pareto‐optimal solutions and select a small number of preferred solutions. This is extremely useful to modelers who typically are required to provide the best estimated parameter sets with good overall model performance.
A note on in situ estimates of sorption using push‐pull tests
Authors: Cassiani Giorgio , Burbery Lee F. , Giustiniani Michela
Published: March 2005

A sensitivity analysis reveals that large uncertainty exists in estimates of solute retardation factor R made from sorption push‐pull tests. A simplified push‐pull data interpretation method for estimating instantaneous linear sorption in confined aquifers is developed. The new method is less restrictive in its application than the conventional method that uses an approximate analytical solution to the push‐pull test problem.
The singlet model of the anisotropic magnetization of the III-VI diluted magnetic semiconductor, In1−xMnxS
Authors: Franzese G. , Byrd Ashlee , Tracy J. L. , Garner J. , Pekarek T. M. , Miotkowski I. , Ramdas A. K.
Published: March 2005

Results for the anisotropic magnetization of the III-VI diluted magnetic semiconductor (DMS), In1−xMnxS, are presented. The compound has a markedly different crystal structure from previously investigated III-VI crystals. The Hamiltonian includes crystal potential, Zeeman, spin-orbit, and spin-spin terms. The singlet model used assumes that the substitutional Mn are noninteracting which is appropriate when x is small (here 2%). Magnetization versus temperature results are found for several magnetic fields B. The experimental magnetization is compared to our singlet model results with excellent agreement except at low temperatures (⩽20K) where some evidence of possible spin-glass behavior is evident.
Rapidly annealed exchange-coupled Sm–Co∕Co multilayers
Authors: Zhou J. , Skomski R. , Liu Y. , Sui Y. C. , Liu W. , Sellmyer D. J.
Published: March 2005

In exchange-coupled two-phase permanent magnets, the length scale of soft phase is limited to about twice of the domain-wall width of the hard phase. To optimize the energy product, it is important to realize this length experimentally. In this work, we investigate the Sm–Co∕Co hard/soft multilayers with varying thickness of soft phase layers. On rapidly annealing, the multilayered hard-soft structure forms. Transmission electron microscopy micrography confirms that the multilayer structure is retained after the annealing. Single-phase-like hysteresis loops are obtained for samples with Co layers up to 13nm thick. This behavior indicates that the soft phase is well exchange coupled to the neighboring SmCoz hard phase. An optimal energy product of 16.6MGOe has been obtained. Longer annealing time results in more diffusion at the interface and yields two-phase-like hysteresis behavior. Direct current demagnetization measurement shows exchange-spring behavior of the samples annealed for longer time. Micromagnetic simulations with varying interface exchange coupling have been performed to compare with the experimental results.
1
∕
f
-type noise in a biased current perpendicular to the plane spin valve: A numerical study
Authors: Rebei A. , Berger L. , Chantrell R. , Covington M.
Published: March 2005

We add the spin momentum-transfer torque to the stochastic Landau–Lifshitz equation and use it to study the noise spectrum as a function of the current and easy axis field for configurations close to equilibrium. The current perpendicular to the plane structure is biased by a constant field perpendicular to the polarization axis of the pinned layer. We show that this structure can exhibit large 1∕f-type noise for frequencies in the microwave regime. This 1∕f noise is not due to the spin torque. The spin torque can only change the amplitude of the noise.
Magnetic-field parallel motion of living cells
Authors: Iwasaka M. , Ueno S.
Published: March 2005

We discovered that the motion of adherent cells was influenced by strong static magnetic fields and was parallel to the magnetic fields. A real-time observation of living cells in the presence of magnetic fields inside the bore of a superconducting magnet was performed by using a charge-coupled device camera with a monozoom lens. Fibroblastlike cells (MC3T3-E1) were cultured and observed by a video microscope system during magnetic-field exposures at 8T. During the exposure, most cells showed a back-and-forth motion along the direction of the magnetic field. Specifically, the direction of cell extension immediately after cell division was parallel to the magnetic field. Cytoskeletons inside the cells were oriented in parallel with the magnetic fields, and introduced a cell motion parallel with the magnetic field. Our experiments showed that living cells consisting of diamagnetic materials had their motion restricted by the direction of the applied magnetic field.
Magnetoresistance of magnetite point contacts and nanoconstrictions
Authors: Céspedes O. , Clifford E. , Coey J. M. D.
Published: March 2005

Point contacts of magnetite exhibit large, reversible increases of conductance by a factor of up to 5 in the presence of a small magnetic field (<10mT), provided the conductance is less than the quantum of conductance G0 (12900Ω)−1. Smaller effects are found in (La0.7Sr0.3)MnO3 and Co2Cr0.6Fe0.4Al. Comparable effects observed in magnetite nanoconstrictions milled using a focused-ion beam in thin films deposited on oxide substrates are only reversible on a time scale of hours. High-resistance nanogaps show evidence of field emission beyond a voltage threshold, which is itself field dependent. The results are discussed in terms of spin-polarized transport, magnetostriction, magnetic dipole strain, and Fowler–Nordheim tunneling.
Kinetics of Ge growth at low temperature on Si(001) by ultrahigh vacuum chemical vapor deposition
Authors: Halbwax M. , Bouchier D. , Yam V. , Débarre D. , Nguyen Lam H. , Zheng Y. , Rosner P. , Benamara M. , Strunk H. P. , Clerc C.
Published: March 2005

The growth of germanium at low temperature by ultrahigh vacuum chemical vapor deposition on Si(001) is investigated in real time by reflection high-energy electron diffraction. These observations are complementarily checked by atomic force microscopy, Rutherford backscattering spectrometry, transmission electron microscopy, and x-ray diffraction experiments. It can be seen that the currently observed Stranski–Krastanov-related two-dimensional (2D) to three-dimensional transition is avoided at 330°C and that the major part of the relaxation process occurs during the deposition of the first two monolayers. Then, the measured in-plane lattice parameter evolves slowly and approaches that of bulk Ge after deposition of 50 monolayers. The corresponding relaxation equals 83%. The resulting surface is flat, with a rms roughness of 0.55nm. The relaxation is found to be mainly due to misfits dislocations located at the Ge∕Si interface. Regrowth experiments at 600°C show that the low-temperature films are not stable for thicknesses below 27nm. In spite of the nearly complete relaxation observed for 7.5nm, a much higher thickness is needed to enable a continuous 2D growth at 600°C. Finally, a 500-nm-thick film, obtained with a low-temperature Ge buffer and with a Ge regrowth at high temperature, exhibits a channeling-to-random Rutherford backscattering spectrometry ratio (χmin) of 4%, which indicates a good crystalline quality.
Recoil energy distributions for dissociation of the van der Waals molecule p-difluorobenzene–Ar with 450–3000cm−1 excess energy
Authors: Bellm Susan M. , Lawrance Warren D.
Published: March 2005

Velocity map imaging has been used to measure the distributions of translational energy released in the dissociation of p-difluorobenzene–Ar van der Waals complexes from the 51¯, 31¯, 52¯, 3151¯, 53¯, 32¯, and 3251¯ states. These states span 818–3317cm−1 of vibrational energy and correspond to a range of energies above dissociation of 451–2950cm−1. The translational energy release (recoil energy) distributions are remarkably similar, peaking at very low energy (10–20cm−1) and decaying in an exponential fashion to approach zero near 300cm−1. The average translational energy released is small, shows no dependence on the initial vibrational energy, and spans the range 58–72cm−1 for the vibrational levels probed. The average value for the seven levels studied is 63cm−1. The low fraction of transfer to translation is qualitatively in accord with Ewing’s momentum gap model [G. E. Ewing, Faraday Discuss. 73, 325 (1982)]. No evidence is found in the distributions for a high energy tail, although it is likely that the experiment is not sufficiently sensitive to detect a low fraction of transfer at high translational energies. The average translational energy released is lower than has been seen in comparable systems dissociating from triplet and cation states.
Dynamics of order formation by colloidal adsorption onto a substrate studied with Brownian dynamics
Authors: Watanabe Satoshi , Miyahara Minoru , Higashitani Ko
Published: March 2005

Colloidal adsorption and spontaneous ordering of adsorbed particles on a substrate was simulated using a three-dimensional simulation model for colloidal dispersion system with an adsorptive surface under a specified bulk concentration, where the particle-particle and particle-substrate interactions were modeled on the DLVO theory. The key process for order formation is considered to be the adsorption of a particle that induces the transition from incomplete order to perfect order, and is found to involve a stochastic nature due to an energy barrier which must be overcome for the system to reach ordered state. Also, a model was developed to predict the energy barrier for order formation based on direct observation of the key process. Further, a model to describe the stochastic nature of the process was developed and its quantitative validity was demonstrated. Through the examination of the key process, it is concluded that the mechanism of the order formation is composed of two successive processes and the rate-determining step varies depending on the ionic strength.