bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial variation of tracer distribution in a structured clay field soil
Authors: Koszinski Sylvia , Quisenberry Virgil , Rogasik Helmut , Wendroth Ole
Published: January 2006

Within the sensitive soils of the River Oder Basin (E Brandenburg, Germany), chloride‐tracer transport was studied with respect to soil‐surface conditions of the well structured clayey topsoil (disturbed vs. undisturbed) and irrigation mode (flooding vs. sprinkling). The spatial variation of chloride and dye distribution was sampled in a regular grid within different soil depths. Different methods were used for the analysis of spatial heterogeneity: a heterogeneity index HI derived from fitting parameters of the cumulative distribution function, semivariogram analyses to identify the spatial representativity of observations and to classify the spatial variation, and Spearman's rank correlations to examine the spatial similarity of tracer distribution across different soil depths.

Soil aggregation was obvious throughout the soil profile, and macropores and fractures were preferred flow paths for the tracer. Flood irrigation resulted in more “uniform” distribution than sprinkling did. However, preferential flow was identified for all treatments, where, once established below the surface layer, flow paths led to heterogeneity indices manifesting nonuniform flow and reduced lateral mixing between macropores and soil matrix. Within the flooded plot, spatial structure of chloride concentration was moderate unlike the strongly structured variation within the sprinkled plots.

For purposes to generalize and to assess regional risk of the water and solute transport within the topsoil of the River Oder Basin, spatial autocorrelation ranges of about 15 cm should be considered and included into concepts of soil protection and land‐use management, soil‐sampling strategies, or modeling approaches.
Cold and hot water–extractable organic matter as indicators of litter decomposition in forest soils
Authors: Landgraf Dirk , Leinweber Peter , Makeschin Franz
Published: January 2006

Mild extractions were used as indicators of easily decomposable organic matter (OM). However, the chemical composition of extracted OM often remained unclear. Therefore, the composition of cold and hot water–extractable OM was investigated in the O horizons (Oi, Oe, Oa) of a 170 y old beech stand (Fagus sylvatica) in the Ore Mtns., SE Germany. To simulate litter decomposition, the O horizon samples were incubated for 1 week under defined conditions. Cold‐ and hot‐water extracts were analyzed and chemically characterized by pyrolysis–field ionization mass spectrometry (Py‐FIMS). The C and N concentrations were always lower in the cold‐(C: 2.69 to 3.95 g kg–1; N: 0.14 to 0.29 g kg–1) than in the hot‐water extracts (C: 13.77 to 15.51 g kg–1; N: 0.34 to 0.83 g kg–1). The C : N ratios of both extracts increased with increasing depth. Incubation increased the concentrations of C and N in all water extracts, while C : N ratios of extracts decreased. The molecular‐chemical composition of cold and hot water–extracted OM revealed distinct differences. Generally, cold water–extracted OM was thermally more stable than hot water–extracted OM. The mass spectra of the hot water–extracted organic matter revealed more intensive signals of carbohydrates, phenols, and lignin monomers. Additionally, the n‐C28 fatty acid and the n‐C38–to–n‐C52 alkyl monoesters clearly distinguished the hot‐ from the cold‐water extract. A principle‐component analysis visualized (1) alterations in the molecular‐chemical composition of cold‐ and hot‐water extracts due to previous incubation of the solid O horizon samples and (2) a decomposition from the Oi to the Oh horizon. This provides evidence that the macromorphological litter decomposition was reflected by the chemical composition of water extracts, and that Py‐FIMS is well‐suited to explain at the molecular level why OM decomposability is correlated with water‐extracted C.
Spatial variability of O layer thickness and humus forms under different pine beech–forest transformation stages in NE Germany
Authors: Bens Oliver , Buczko Uwe , Sieber Sonja , Hüttl Reinhard F.
Published: January 2006

Spatial variability of humus layer (O layer) thicknesses can have important impacts upon soil water dynamics, nutrient storage and availability, as well as plant growth. The purpose of the present study was to elucidate the impact of forest‐transformation practices on the spatial variability of O layer thicknesses. The study focused on the Kahlenberg forest area (NE Germany) with stands of Scots pine (Pinus sylvestris)and European beech (Fagus sylvatica)of different age structures that form a transformation chronosequence from pure Scots pine stands towards pure European beech stands. Topsoil profiles including both, the O layer and the uppermost humic mineral soil horizon were excavated at intervals of 0.4 m along 15–20 m long transects, and spatial variability of O layer thicknesses was quantified by variogram analysis. The correlation lengths of total O layer thickness increased in the sequence consisting of pure pine stand (3.1 m) → older mixed stand (3.7 m) → pure beech stand (4.5 m), with the exception of the younger mixed stand, for which no correlation lengths of total O layer thickness could be determined. The degree of spatial correlation,i.e., the percentage of the total variance which can be described by variograms, was highest for the two monospecies stands, whereas this percentage was distinctly lower for the two mixed stands. A similar minimum for the two mixed stands was observed for the correlation lengths of the Oh horizon. These results suggest that the spatial structures of forest‐transformation stands may be interpreted in terms of a disturbance (in the form of the underplanting of beech trees). After this disturbance, the forest ecosystem requires at least 100 y to again reach relative equilibrium. These findings are in line with the results of other soil‐related investigations at these sites.
Effect of subcritical hydrophobicity in a sandy soil on water infiltration and mobile water content
Authors: Lamparter Axel , Deurer Markus , Bachmann Jörg , Duijnisveld Wilhelmus H. M.
Published: January 2006

Recent research shows that most soils are more or less water repellent. Already subcritical water repellency may cause incomplete soil wetting and preferential flow. Both processes potentially reduce the residence time of water and solutes in the vadose zone, resulting in an enhanced risk of groundwater contamination. The objective of the present paper is, therefore, to evaluate the impact of reduced soil wettability on the soil water infiltration rate and to investigate the tendency towards preferential flow with the analysis of the immobile water content in the infiltration zone.

In november 2002, a field experiment was done in a coniferous forest, 30 km N of Hannover, Germany. Soil hydrophobicity was quantified by measuring the contact angles. The hydraulic conductivity of the podsolic sandy soil was measured depth‐dependent with a double‐ring tension infiltrometer in three soil horizons. To quantify possible preferential‐flow effects, a LiBr‐Tracer was added to the infiltrating water to evaluate the mobile water‐content fraction after infiltration. Additionally, infiltration rates of water were compared with infiltration rates of ethanol which were determined after water infiltration at the same locations.

Results show that the actual water repellency of field‐moist soil was mainly subcritical (contact angle <90°). Water infiltration rates were reduced due to subcritical repellency by a factor of 3–170 compared with ethanol infiltration rates (exclusion of wetting effects). This spatially variable infiltration behavior was not clearly reflected neither by the small‐scale contact‐angle measurements nor by the analysis of the average immobile soil water content in the infiltration zone. We conclude that this specific infiltration behavior of water caused by small‐scale wettability effects may temporarily reduce the local connectivity of water‐flow pathways.
Abbau von Isoproturon in Regenwurm‐Makroporen und in der Unterbodenmatrix – Eine Feldstudie
Authors: Bolduan Rainer , Zehe Erwin
Published: January 2006

Um zu klären, wie lange durch präferenziellen Transport in den Unterboden gelangte Herbizide dort persistieren, wird beispielhaft der mikrobielle Abbau des Herbizids Isoproturon am Ende von Makroporen/Wurmgängen in 80–100 cm Tiefe mit dem Abbau in der umgebenden Bodenmatrix verglichen. Dazu wurde eine Methode entwickelt, welche die Messung des Isoproturon‐Abbaus in Makroporen unter Feldbedingungen erlaubt. Nach Voruntersuchungen zur Optimierung von Applikation und Probennahme wurden im Einzugsgebiet des Weiherbachs (Kraichgau, SW Deutschland) auf einer überdachten Versuchsparzelle 55 Wurmgänge mit einer Tiefe von 80–100 cm mit Isoproturon beimpft. In Boden der Versuchsparzelle wurden parallel Bodenfeuchte und ‐temperatur kontinuierlich gemessen. Jeweils 5–6 der beimpften Wurmgänge wurden alle 8 Tage herauspräpariert und auf ihren Gehalt an Isoproturon untersucht, um die Kinetik des Abbaus zu ermitteln. Parallel erfolgte die Untersuchung des Abbaus von Isoproturon in der die Wurmgänge umgebenden Bodenmatrix im Labor. Die Ergebnisse der Feld‐ und Laborversuche zeigen, dass der mikrobielle Abbau von Isoproturon direkt am Ende der Wurmgänge mit einem DT‐50‐Wert von 15,6 d ähnlich schnell erfolgt wie im Oberboden. Bereits wenige Zentimeter vom Zentrum des Wurmgangs entfernt zeigte sich in der umgebenden Unterbodenmatrix innerhalb von 30 d kein Abbau von Isoproturon. Diese deutliche Zunahme der Persistenzzeit konnte durch die wesentlich geringere mikrobielle Aktivität in der umgebenden Bodenmatrix erklärt werden. Für das Schicksal eines Herbizids, welches durch präferenzielle Fließereignisse in den Unterboden gelangt ist, ist somit entscheidend, ob es aus der Makropore in die umgebende Bodenmatrix transportiert wird oder nicht, denn die Abbauraten im Unterboden nehmen bereits nach wenigen Zentimetern um etwa eine Größenordnung ab. Aussagen dieser Genauigkeit sind selbst mit hochauflösenden Prozessmodellen bestenfalls für extrem gut untersuchte Standorte ableitbar.
How representatively can we sample soil mineral nitrogen?
Authors: Giebel Antje , Wendroth Ole , Isaak Reuter Hannes , Kersebaum Kurt‐Christian , Schwarz Jürgen
Published: January 2006

Spatial distribution of soil mineral‐N content (Nmin) is a scale‐variant process. Precision farming assumes knowledge about the spatial distribution of Nmin. Moreover, sampling in management zones is based on the assumption of spatial dependence between sampling points. In the present study, variability structure of Nmin and the sources of variability were investigated. Within an agricultural landscape, Nmin was investigated across a field in a nested design over four consecutive years. Temporally unstable structure of individual nests require a sampling with several nests in the field. In the investigated field, 35%–49% of the total variability derived from small‐scale variability observed at spatial distances of <5 m and from sampling and analytical errors. Differences between 10 and 26 kg N ha–1 for the soil depth increment 0–60 cm can be expected. Uncertainty due to analytical errors were in the order of 5–10 kg N ha–1 for a 0–60 cm layer.
Influence of fruit treatments on perishability during cold storage of sweet chestnuts
Authors: Jermini Mauro , Conedera Marco , Sieber Thomas N , Sassella Alberto , Schärer Hans , Jelmini Giorgio , Höhn Ernst
Published: January 2006

With a view to enhancing the quality of local chestnut in southern Switzerland, the impact of three treatments [‘soaking’, ‘cold bath’ (hydrotherapy) and ‘warm bath’ (thermo‐hydrotherapy)] on the qualitative, chemical and sensory characteristics of the nuts during 90 days of cold storage was evaluated. Weight and water content decreased significantly with increasing duration of storage. Starch content decreased following a negative logistic trend. Sucrose, however, increased steeply according to a monomolecular trend and was significantly higher between 0 and 60 days of storage in the soaked chestnuts than in the cold‐bath treated nuts. The mean proportion of mouldy fruit remained constant at 27% for the warm‐bath treated nuts and increased from 16 to 30% for the cold‐bath treated fruit and from 28 to 63% for the soaked nuts during the 90 days of cold storage. The most frequently isolated moulds were Ciboria batschiana, Penicillium spp. and Mucor hiemalis. Warm and cold baths were successful in eliminating the larvae of Cydia splendana but the cold bath was inadequate to control Curculio elephas. Cold bath significantly reduced the sensory qualities (sweetness, aroma, texture) of the nuts, but made them easier to peel, as did the warm bath. Copyright © 2006 Society of Chemical Industry
Effects of germination on the activities of amylases and phenolic enzymes in sorghum varieties grouped according to food end‐use properties
Authors: Dicko Mamoudou H , Gruppen Harry , Zouzouho Obou C , Traoré Alfred S , van Berkel Willem JH , Voragen Alphons GJ
Published: January 2006

Fifty sorghum varieties were screened to determine the effects of germination on levels of starch, α‐amylase, β‐amylase, phenylalanine ammonia lyase (PAL), peroxidase (POX) and polyphenol oxidase (PPO). Germination decreased starch content, with amylose being more degraded than amylopectin. In germinated grain, α‐amylase activity increased several‐fold in all varieties, whereas β‐amylase activity did not increase uniformly and even decreased in some varieties. Activity of the key enzyme in phenolic biosynthesis, PAL, was detected in only half of the varieties before germination but in all of them after germination. PPO was not activated in germinated sorghum grains, whereas POX activity increased up to tenfold in some varieties. Zymography revealed that germination induced de novo synthesis of several POX isoenzymes, among which an anionic POX isoenzyme (pI 3.1) was ubiquitously present. Amylase and phenolic enzyme activities could be correlated with grain and plant agronomic characteristics. The use of sorghum varieties for local dishes such as ‘tô’, ‘dolo’, couscous and thin porridge could be correlated with amylase and phenolic enzyme activities and the contents of their substrates. The biochemical constituents determined are useful markers for selection of varieties for food utilisation with special emphasis on infant porridges. Copyright © 2006 Society of Chemical Industry
Rapid high‐resolution T1 mapping by variable flip angles: Accurate and precise measurements in the presence of radiofrequency field inhomogeneity
Authors: Cheng Hai‐Ling Margaret , Wright Graham A
Published: January 2006

Rapid 3D mapping of T1 relaxation times is valuable in diverse clinical applications. Recently, the variable flip angle (VFA) spoiled gradient recalled echo approach was shown to be a practical alternative to conventional methods, providing better precision and speed. However, the method is known to be sensitive to transmit field (B1+) inhomogeneity and can result in significant systematic errors in T1 estimates, especially at high field strengths. The main challenge is to improve the accuracy of the VFA approach without sacrificing speed. In this article, the VFA method was optimized for both accuracy and precision by considering the influence of imperfect transmit fields, noise bias, and selection of flip angles. An analytic solution was developed for systematic B1+‐induced T1 errors and allows simple correction of T1 measurements acquired with any imaging parameters. A noise threshold was also identified and provided a guideline for avoiding T1 biases. Finally, it was shown that three flip angles were the most efficient for maintaining accuracy and high precision over large ranges of T1. A rapid B1+ mapping sequence was employed in all phantom experiments and high‐field in vivo brain scans. Experimental results confirmed the theory and validated the accuracy of the proposed method. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Effect of the intracellular localization of a Gd‐based imaging probe on the relaxation enhancement of water protons
Authors: Terreno Enzo , Geninatti Crich Simonetta , Belfiore Simona , Biancone Luigi , Cabella Claudia , Esposito Giovanna , Manazza Andrea D. , Aime Silvio
Published: January 2006

Gd‐HPDO3A has been internalized into rat hepatocarcinoma cells in the cytoplasm (by electroporation) or in intracellular vesicles (by pinocytosis), respectively. In the former case, the observed relaxation rates are likely dependent upon the amount of internalized paramagnetic complex, whereas in the latter case the relaxation enhancement is “quenched” to a plateau value (about 3 s−1) when the entrapped amount of Gd‐chelate is higher than 1 × 1010 Gd/cell. The observed behavior has been accounted in terms of a theoretical treatment based on equations formally derived by Labadie et al. (J Magn Reson B 1994;105:99–102). On this basis, entrapment into intracellular vesicles has been treated as a three‐site water exchange (extracellular/cytoplasm/vesicle compartments), whereas the cell pellets containing the paramagnetic agent spread out in the cytoplasm can be analyzed by a two‐site exchange system. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Retrospective gating for mouse cardiac MRI
Authors: Bishop Jonathan , Feintuch Akiva , Bock Nicholas A. , Nieman Brian , Dazai Jun , Davidson Lorinda , Henkelman R. Mark
Published: January 2006

Cardiac MR imaging in small animals presents some difficulties due to shorter cardiac cycles and smaller dimensions than in human beings, but prospectively gated techniques have been successfully applied. As with human imaging, there may be certain applications in animal imaging for which retrospective gating is preferable to prospective gating. For example, cardiac imaging in multiple mice simultaneously is one such application. In this work we investigate the use of retrospective gating for cardiac imaging in a mouse. Using a three‐dimensional imaging protocol, we show that image quality with retrospective gating is comparable to prospectively gated imaging. We conclude that retrospective gating is applicable for small animal cardiac MRI and show how it can be applied to the problem of cardiac MRI in multiple mice. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
T1 measurement of 31P metabolites at rest and during steady‐state dynamic exercise using a clinical nuclear magnetic resonance scanner
Authors: Cettolo V. , Piorico C. , Francescato M. P.
Published: January 2006

This article illustrates some problems and possible solutions to determine the apparent spin–lattice relaxation time (T1) of the muscular 31P metabolites at rest and during dynamic steady‐state exercise using a clinical 1.5 T NMR scanner and a surface coil. T1 was first estimated on a phosphates solution (phantom) using four different acquisition protocols, all based on the multiple‐point “progressive saturation” method, and by fitting each data set with two different mathematical models. Subsequently, two of the four protocols and both models were used to estimate T1 both at rest and during exercise on the calf muscles of 10 healthy volunteers. Experimental results obtained on the phantom showed that T1 is greatly affected by the longest nominal explored repetition time (P < 0.001) and by the mathematical model (P < 0.001), ranging from 0.65 ± 0.10 to 8.4 ± 0.8 s. The two acquisition protocols applied on volunteers yielded significantly different T1 (P < 0.001), which were also rather different from the literature values for the same metabolites. Nevertheless, independently of the acquisition protocol and/or the fitting procedure, T1 of all muscular phosphagens did not change statistically from rest to steady‐state aerobic exercise. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Navigator gated high temporal resolution tissue phase mapping of myocardial motion
Authors: Jung Bernd , Zaitsev Maxim , Hennig Jürgen , Markl Michael
Published: January 2006

Data acquisition for phase contrast velocity mapping of myocardial motion is typically based on multiple breath‐held 2D measurements with limited acquisition duration and consequently relatively poor temporal resolution. In order to overcome the limitations of breath‐hold acquisitions, an improved navigator‐guided technique was implemented based on 2 navigator signals within each cardiac cycle in combination with paired acceptance and rejection criteria of successive navigator signals. Respiratory gated phase contrast measurements with 3‐directional velocity encoding were performed in 12 healthy volunteers in basal, midventricular, and apical locations of the left ventricle during free breathing with a temporal resolution of 13.8 ms. Results were compared to standard breath‐hold measurements with a temporal resolution of 69 ms. Data from the high temporal resolution study revealed details in left ventricular motion patterns that were previously not seen in phase contrast measurements and are only known from echocardiography. The proposed navigator gated technique for high temporal resolution velocity mapping is, therefore, highly promising for the detection of local and global motion abnormalities in patients with disturbed left ventricular performance, such as diastolic dysfunction. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
The discrete null space method for the energy consistent integration of constrained mechanical systems. Part II: multibody dynamics
Authors: Betsch Peter , Leyendecker Sigrid
Published: January 2006

In the present work, rigid bodies and multibody systems are regarded as constrained mechanical systems at the outset. The constraints may be divided into two classes: (i) internal constraints which are intimately connected with the assumption of rigidity of the bodies, and (ii) external constraints related to the presence of joints in a multibody framework. Concerning external constraints lower kinematic pairs such as revolute and prismatic pairs are treated in detail. Both internal and external constraints are dealt with on an equal footing. The present approach thus circumvents the use of rotational variables throughout the whole time discretization. After the discretization has been completed a size‐reduction of the discrete system is performed by eliminating the constraint forces. In the wake of the size‐reduction potential conditioning problems are eliminated. The newly proposed methodology facilitates the design of energy–momentum methods for multibody dynamics. The numerical examples deal with a gyro top, cylindrical and planar pairs and a six‐body linkage. Copyright © 2006 John Wiley & Sons, Ltd.
Parallel asynchronous particle swarm optimization
Authors: Koh Byung‐Il , George Alan D. , Haftka Raphael T. , Fregly Benjamin J.
Published: January 2006

The high computational cost of complex engineering optimization problems has motivated the development of parallel optimization algorithms. A recent example is the parallel particle swarm optimization (PSO) algorithm, which is valuable due to its global search capabilities. Unfortunately, because existing parallel implementations are synchronous (PSPSO), they do not make efficient use of computational resources when a load imbalance exists. In this study, we introduce a parallel asynchronous PSO (PAPSO) algorithm to enhance computational efficiency. The performance of the PAPSO algorithm was compared to that of a PSPSO algorithm in homogeneous and heterogeneous computing environments for small‐ to medium‐scale analytical test problems and a medium‐scale biomechanical test problem. For all problems, the robustness and convergence rate of PAPSO were comparable to those of PSPSO. However, the parallel performance of PAPSO was significantly better than that of PSPSO for heterogeneous computing environments or heterogeneous computational tasks. For example, PAPSO was 3.5 times faster than was PSPSO for the biomechanical test problem executed on a heterogeneous cluster with 20 processors. Overall, PAPSO exhibits excellent parallel performance when a large number of processors (more than about 15) is utilized and either (1) heterogeneity exists in the computational task or environment, or (2) the computation‐to‐communication time ratio is relatively small. Copyright © 2006 John Wiley & Sons, Ltd.
Imperfection sensitivity due to coupled local instability: a non‐convex QP solution algorithm
Authors: Casciaro Raffaele , Mancusi Giovanna
Published: January 2006

The paper deals with the collapse safety of slender elastic structures subjected to local buckling interaction. Using Koiter's asymptotic approach, the mechanical problem is reduced to the search for all the local minima of an indefinite quadratic form over the unit simplex. An efficient recursive branch‐and‐cut algorithm is proposed for solving this non‐convex QP problem, allowing a numerical procedure providing statistical information about the collapse load for a given distribution of random imperfections to be set up. Copyright © 2006 John Wiley & Sons, Ltd.
Time‐parallel implicit integrators for the near‐real‐time prediction of linear structural dynamic responses
Authors: Farhat Charbel , Cortial Julien , Dastillung Climène , Bavestrello Henri
Published: January 2006

The time‐parallel framework for constructing parallel implicit time‐integration algorithms (PITA) is revisited in the specific context of linear structural dynamics and near‐real‐time computing. The concepts of decomposing the time‐domain in time‐slices whose boundaries define a coarse time‐grid, generating iteratively seed values of the solution on this coarse time‐grid, and using them to time‐advance the solution in each time‐slice with embarrassingly parallel time‐integrations are maintained. However, the Newton‐based corrections of the seed values, which so far have been computed in PITA and related approaches on the coarse time‐grid, are eliminated to avoid artificial resonance and numerical instability. Instead, the jumps of the solution on the coarse time‐grid are addressed by a projector which makes their propagation on the fine time‐grid computationally feasible while avoiding artificial resonance and numerical instability. The new PITA framework is demonstrated for a complex structural dynamics problem from the aircraft industry. Its potential for near‐real‐time computing is also highlighted with the solution of a relatively small‐scale problem on a Linux cluster system. Copyright © 2006 John Wiley & Sons, Ltd.
Advanced materials for 193 nm immersion lithography
Authors: Kusumoto Shiro , Shima Motoyuki , Wang Yong , Shimokawa Tsutomu , Sato Hozumi , Hieda Katsuhiko
Published: January 2006

Recently 193 nm immersion lithography is considered the most promising next generation technology which will enable a 45 nm and below node device to be manufactured. This will lead to not only depth of focus (DOF) enlargement, but immersion lithography enables the use of a hyper numerical aperture (NA) larger than 1.0 and achieve higher resolution capability. For 193 nm lithography, water is an ideal immersion fluid, providing suitable refractive index and transmission properties. Furthermore the higher refractive index fluid is expected to provide a potential extension of optical lithography to the 32 nm node. This paper describes the critical issues of the water immersion lithography process, such as photoresist component leaching into water, defectivity etc. Leaching materials were analyzed by liquid chromatography‐mass spectrometry (LC‐MS) and were found to be composed of the photoacid generator (PAG) and its decomposed chemicals. The leaching amount is in the order of 10−12 mol/cm2 with a normal 193 nm photoresist. An other issue to be studied is the water‐mark defect caused by small waters droplets left on the exposed wafer. These undesirable phenomenons could be prevented by applying a topcoat material onto the photoresist film. Material design for the topcoat material and its physical and lithographic properties are discussed in detail. Development of a high refractive index fluid is also discussed in this paper. A promising high refractive index fluid HIL‐001 was developed which has a higher refractive index (n = 1.64) than water and high transparency (98%/mm) at 193 nm wavelength. Immersion exposure experiments using high refractive index fluid with and without topcoat material was carried out and 32 nm L/S imaging capability was demonstrated by using a two‐beam interferometric exposure tool. Copyright © 2006 John Wiley & Sons, Ltd.
Molecular characterisation of a prenatally diagnosed 5q15q21.3 deletion and review of the literature
Authors: Malan Valérie , Martinovic Jelena , Sanlaville Damien , Caillat Stéphanie , Perrier Waill Marie‐Christine , Maurin Ganne Marie‐Laure , Tantau Julia , Attie‐Bitach Tania , Vekemans Michel , Morichon‐Delvallez Nicole
Published: January 2006

Background

Ultrasound examination performed on a 32‐year old woman at 30 weeks' gestation showed the presence of fetal malformations. Amniocentesis was performed.

Methods and Results

Cytogenetic analysis of cultured amniocytes revealed an interstitial deletion of the long arm of chromosome 5. Molecular studies confirmed that the deletion included the 5q15‐21.3 region and was 14 Mb in size. Therefore, the karyotype was: 46,XY,del(5)(q15q21.3). In addition, analysis of polymorphic DNA markers showed that the deletion was of paternal origin.

Conclusions

The pregnancy was terminated at 34 weeks' gestation. At autopsy, the fetus displayed dysmorphic features, thin limbs and renal abnormalities. The clinical findings observed in the fetus as well as in 20 cases reported previously allowed us to further delineate the phenotype of such interstitial 5q15q21.3 deletions. Copyright © 2006 John Wiley & Sons, Ltd.
Sensitivity analysis and external adjustment for unmeasured confounders in epidemiologic database studies of therapeutics
Authors: Schneeweiss Sebastian
Published: January 2006

Background

Large health care utilization databases are frequently used to analyze unintended effects of prescription drugs and biologics. Confounders that require detailed information on clinical parameters, lifestyle, or over‐the‐counter medications are often not measured in such datasets, causing residual confounding bias.

Objective

This paper provides a systematic approach to sensitivity analyses to investigate the impact of residual confounding in pharmacoepidemiologic studies that use health care utilization databases.

Methods

Four basic approaches to sensitivity analysis were identified: (1) sensitivity analyses based on an array of informed assumptions; (2) analyses to identify the strength of residual confounding that would be necessary to explain an observed drug‐outcome association; (3) external adjustment of a drug‐outcome association given additional information on single binary confounders from survey data using algebraic solutions; (4) external adjustment considering the joint distribution of multiple confounders of any distribution from external sources of information using propensity score calibration.

Conclusion

Sensitivity analyses and external adjustments can improve our understanding of the effects of drugs and biologics in epidemiologic database studies. With the availability of easy‐to‐apply techniques, sensitivity analyses should be used more frequently, substituting qualitative discussions of residual confounding. Copyright © 2006 John Wiley & Sons, Ltd.
Person‐factors in the California Adult Q‐Set: closing the door on personality trait types?
Authors: McCrae Robert R. , Terracciano Antonio , Costa Paul T. , Ozer Daniel J.
Published: January 2006

To investigate recent hypotheses of replicable personality types, we examined data from 1540 self‐sorts on the California Adult Q‐Set (CAQ). Conventional factor analysis of the items showed the expected Five‐Factor Model (FFM). Inverse factor analysis across random subsamples showed that none of the previously reported person‐factors were replicated. Only two factors were replicable, and, most importantly, these factors were contaminated by mean level differences in item endorsement. Results were not due to sample size or age heterogeneity. Subsequent inverse factor analysis of standardized items revealed at least three replicable factors; when five person‐factors were extracted, they could be aligned precisely with the dimensions of the FFM. The major factors of person similarity can be accounted for entirely in terms of the FFM, consistent with the hypothesis that there are no replicable personality types in the CAQ. Published in 2006 John Wiley & Sons, Ltd.
An enhanced elastic network model to represent the motions of domain‐swapped proteins
Authors: Song Guang , Jernigan Robert L.
Published: January 2006

Domain swapping is a process where two (or more) protein molecules form a dimer (or higher oligomer) by exchanging an identical domain. In this article, based on the observation that domains are rigid and hinge loops are highly flexible, we propose a new Elastic Network Model, domain‐ENM, for domain‐swapped proteins. In this model, the rigidity of domains is taken into account by using a larger spring constant for intradomain contacts. The large‐scale transition of domain swapping is then novelly decomposed into the relative motion between the rigid domains (only 6 degrees of freedom) plus the internal fluctuations of each domain. Consequently, this approach has the potential to produce much more meaningful transition pathways than other simulation approaches that try to find pathways in a search space of large numbers of dimensions. In this article, we also propose a new way to define the overlap measure. Past approaches used an inappropriate comparison of the large‐scale conformation displacement against the computed infinitesimal motions of modes. Here, we propose an infinitesimal version of the large‐scale conformation change and then compare it with the modes of motions. As a result, we obtain much better overlap values. Using this new overlap definition, we are also able for the first time to give a clear, intuitive explanation why “open” forms tend to produce better overlap values than “closed” forms with traditional ENMs. Finally, as an application, we present a simple approach to show how domain‐ENM can be used to generated transition pathways for domain‐swapped proteins. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Evaluation of different biological data and computational classification methods for use in protein interaction prediction
Authors: Qi Yanjun , Bar‐Joseph Ziv , Klein‐Seetharaman Judith
Published: January 2006

Protein–protein interactions play a key role in many biological systems. High‐throughput methods can directly detect the set of interacting proteins in yeast, but the results are often incomplete and exhibit high false‐positive and false‐negative rates. Recently, many different research groups independently suggested using supervised learning methods to integrate direct and indirect biological data sources for the protein interaction prediction task. However, the data sources, approaches, and implementations varied. Furthermore, the protein interaction prediction task itself can be subdivided into prediction of (1) physical interaction, (2) co‐complex relationship, and (3) pathway co‐membership. To investigate systematically the utility of different data sources and the way the data is encoded as features for predicting each of these types of protein interactions, we assembled a large set of biological features and varied their encoding for use in each of the three prediction tasks. Six different classifiers were used to assess the accuracy in predicting interactions, Random Forest (RF), RF similarity‐based k‐Nearest‐Neighbor, Naïve Bayes, Decision Tree, Logistic Regression, and Support Vector Machine. For all classifiers, the three prediction tasks had different success rates, and co‐complex prediction appears to be an easier task than the other two. Independently of prediction task, however, the RF classifier consistently ranked as one of the top two classifiers for all combinations of feature sets. Therefore, we used this classifier to study the importance of different biological datasets. First, we used the splitting function of the RF tree structure, the Gini index, to estimate feature importance. Second, we determined classification accuracy when only the top‐ranking features were used as an input in the classifier. We find that the importance of different features depends on the specific prediction task and the way they are encoded. Strikingly, gene expression is consistently the most important feature for all three prediction tasks, while the protein interactions identified using the yeast‐2‐hybrid system were not among the top‐ranking features under any condition. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Correlation between the electric and conical‐uniaxial ferromagnetic phase transitions in the metallic spinel CuCr2Se4
Authors: Tokiwa N. , Hidaka M.
Published: January 2006

The electric resistivity in CuCr2Se4 has been measured below room temperature under applied magnetic fields (H ) up to 1.0 T in the metallic ferromagnetic phase, in addition to magnetization measurements. The temperature dependence of the electric resistivity (ρ ) shows an electric phase transition at about 65 K (T e) and a different linearity of ρ –T curves in the regions of T < 60 K and T > 100 K. Both regions are metallic, while in the intermediate region 60 K < T < 100 K a semiconductor‐like state occurs. The T e transition temperature slightly decreases from about 65 K to 59 K on increasing the magnetic field. The magnetoresistance (MR) shows a crossover to a positive value or a negative one below and above T e, though the MR–T curves depend on the magnetic fields. The magnetization curves deviate from a tentative Brillouin function at about 65 K (H = 50 G), 200 K (H = 400 G), 230 K (H = 800 G) and 170 K (H = 0.2 T), and a weak modulation at about 65 K to 70 K (T 1) under the magnetic fields. It is suspected that the magnetic transition occurring at T 1 is from a conical to a uniaxial ferromagnetic state on heating. The T e electric transition results from a slight change of a Zener band situation, which is induced by a spin‐dependent double‐exchange interaction at T 1. The intermediate semiconductor‐like state is between two different Zener band situations in the conical and uniaxial ferromagnetic states, which are both metallic. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Competition between the intratube curvature and intertube coupling effects in carbon nanotube bundles
Authors: Shao L. B. , Ding J. W. , Xing D. Y.
Published: January 2006

Taking into account the intratube curvature and intertube coupling effects, we develop a tight‐binding approach to study the electronic structure in carbon nanotube bundles. It is found that the curvature develops a small energy gap in the electronic density of states of a zigzag nanotube, while the intertube coupling decreases the gap width. The competition between the two factors may lead to creation or destruction of the energy gap in the carbon nanotube bundles. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lagrange‐mesh method for quantum‐mechanical problems
Authors: Baye Daniel
Published: January 2006

The Lagrange‐mesh method is an approximate variational calculation with the simplicity of a mesh calculation because of the use of a consistent Gauss quadrature. The method can be used for quantum‐mechanical bound‐state and scattering problems with local and non‐local interactions or with a semi‐relativistic kinetic energy, and for solving the time‐dependent Schrödinger equation. No analytical evaluation of matrix elements is needed. The accuracy is exponential in the number of mesh points and is not significantly reduced with respect to the corresponding variational calculations. Lagrange functions can be based on classical or non‐classical orthogonal polynomials as well as on trigonometric and sinc functions, as described in examples. Some singularities can be handled with a regularization technique. Applications to three‐body systems are discussed for various choices of coordinate systems. The helium atom and hydrogen molecular ion are presented as examples. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Implementation of linear‐scaling plane wave density functional theory on parallel computers
Authors: Skylaris Chris‐Kriton , Haynes Peter D. , Mostofi Arash A. , Payne Mike C.
Published: January 2006

We describe the algorithms we have developed for linear‐scaling plane wave density functional calculations on parallel computers as implemented in the onetep program. We outline how onetep achieves plane wave accuracy with a computational cost which increases only linearly with the number of atoms by optimising directly the single‐particle density matrix expressed in a psinc basis set. We describe in detail the novel algorithms we have developed for computing with the psinc basis set the quantities needed in the evaluation and optimisation of the total energy within our approach. For our parallel computations we use the general Message Passing Interface (MPI) library of subroutines to exchange data between processors. Accordingly, we have developed efficient schemes for distributing data and computational load to processors in a balanced manner. We describe these schemes in detail and in relation to our algorithms for computations with a psinc basis. Results of tests on different materials show that onetep is an efficient parallel code that should be able to take advantage of a wide range of parallel computer architectures. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Car–Parrinello molecular dynamics using real space wavefunctions
Authors: Schmid R. , Tafipolsky M. , König P. H. , Köstler H.
Published: January 2006

A Car–Parrinello molecular dynamics implementation using real space discretized wavefunctions on equidistant Cartesian grids is presented. By using numerically discretized Laplace operators of higher order for the evaluation of the electronic kinetic energy as well as for the Poisson equation the total energy expression can be evaluated purely with local operations. Details of our implementation of microcanonical and canonical Car–Parrinello joint dynamics of nuclei and wavefunctions are described. For energy conserving molecular dynamics the exact partial derivatives of the energy expression with respect to the numerical wavefunctions must be available. This aspect is discussed for all contributions to the electronic energy. The crucial point is the efficient iterative solution of the Poisson equation. It is shown that energy conserving dynamics with real space wavefunctions is possible. Our object oriented code is fully parallelized and efficient also for the investigation of systems of realistic size. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Excitonic states of ZnSe detected by microwave‐modulated reflectivity
Authors: Wolverson D. , Smith L. C. , Bingham S. J. , Davies J. J.
Published: January 2006

Signals ascribed to the 1s, 2s and 3s exciton states of epitaxial ZnSe are observed in experiments aimed at detecting the coherent spin‐flip of conduction band electrons under simultaneous microwave and laser excitation of a ZnSe sample in a magnetic field. The origin of these unexpected signals is investigated, since they must arise from non‐idealities in the experiment which could represent a limiting factor in its application to semiconductor heterostructures. It is shown that both magnetic circular dichroism and magnetic linear dichroism effects could lead to the observation of such signals. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cyclotron resonance in II–VI semiconductors at THz region
Authors: Imanaka Y. , Takamasu T. , Takehana K. , Oshikiri M. , Kido G. , Nojiri H. , Matsuda Y. H. , Arimoto H. , Takeyama S. , Miura N. , Karczewski G. , Wojtowicz T. , Kossut J.
Published: January 2006

Cyclotron resonance experiments for various II–VI semiconductors (n‐ZnO, n‐ZnS, n‐ZnSe, n‐CdS, n‐CdSe, n‐CdTe) have been performed at ultra‐high magnetic fields beyond 100 T. Cyclotron resonance and impurity related resonance are observed definitely with the use of THz radiation sources, and the magnetic field dependence of effective mass is obtained at a wide range of a THz region in n‐type CdTe. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
EPR of Nd3+ in congruent and nearly stoichiometric lithium niobate
Authors: Malovichko G. , Grachev V. , Okulov S. , Kokanyan E. , Henecker F. , Hofstaetter A. , Schirmer O.
Published: January 2006

The cover picture refers to the article by Galina Malovichko et al. which has been selected as Editor's Choice for this issue [1]. The lower part of the figure shows a section of the angular dependence of the EPR spectra in the xy‐plane for nearly stoichiometric LiNbO3:Nd3+. The solid lines correspond to non‐magnetic neodymium isotopes of axial C3 symmetry (green) and low C1 symmetry (purple and blue), respectively; the symbols represent experimental data. The upper part of the figure shows possible structures of the nearest surrounding for the C3 and C1 centers and their correspondence to the observed line positions.

The first author Galina Malovichko is Associate Professor in the Physics Department at the Montana State University, USA. Her scientific activity is devoted to experimental condensed matter physics, particularly to the study of structures of extrinsic, intrinsic and radiation defects and their influence on crystal prop‐erties. Her group is involved in the characterization of various materials and optimization of their parameters for advanced ap‐plications.
Charge‐carrier mobilities in disordered semiconducting polymers: effects of carrier density and electric field
Authors: Meisel K.D. , Pasveer W.F. , Cottaar J. , Tanase C. , Coehoorn R. , Bobbert P.A. , Blom P.W.M. , de Leeuw D.M. , Michels M.A.J.
Published: January 2006

The cover picture of this issue of physica status solidi (c) has been taken from the article [1].
The effect of the levonorgestrel intrauterine system on uterine artery blood flow 1 year after insertion
Authors: Haberal A. , Kayikcioglu F. , Gunes M. , Kaplan M. , Ozdegirmenci O.
Published: January 2006

Objective

To assess whether the morphological alterations of the endometrium induced by the levonorgestrel intrauterine system affect the uterine artery vasculature.

Methods

Forty‐eight premenopausal women attending our gynecology clinic because of menorrhagia were enrolled into the study. Clinical measures of menstrual bleeding, endometrial thickness and Doppler flow of the uterine artery (resistance (RI) and pulsatility (PI) indices) were evaluated before and 1 year after insertion of the levonorgestrel intrauterine system. Thirty‐three (69%) women were available for re‐evaluation at the end of the first year and the continuation rate was 76% (n = 25). A paired samples t‐test and the Mann–Whitney U‐test were used for comparison of values between groups.

Results

The mean age of the thirty‐three patients was 44.3 ± 7.6 years. Nine patients (27.3%) were amenorrheic and three patients were in menopause at the end of the year. After excluding the women in menopause, the increase in mean RI 1 year after insertion was statistically significant (0.86 ± 0.07 vs. 0.81 ± 0.08; P = 0.046), as was the decrease in uterine volume (736.9 ± 276.9 mL vs. 972.75 ± 465.71 mL; P = 0.029). The mean endometrial thickness decreased 1 year after insertion, but not significantly (4.6 ± 1.6 mm vs. 6.6 ± 3.5 mm; P = 0.07) and there was no statistically significant difference in mean PI between the groups (2.00 ± 0.63 and 2.03 ± 0.64 pre‐ and post‐insertion, respectively; P = 0.83).

Conclusion

The increase in mean RI of the uterine artery and the decrease in uterine volume 1 year after insertion of the levonorgestrel intrauterine system may be related to its progestational effect. This increase in RI may have a role in cessation of menstruation. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.