bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identifying the primitive path mesh in entangled polymer liquids
Authors: Sukumaran Sathish K. , Grest Gary S. , Kremer Kurt , Everaers Ralf 
Published: March 2005

AbstractSimilar to entangled ropes, polymer chains cannot slide through each other. These topological constraints, the so‐called entanglements, dominate the viscoelastic behavior of high‐molecular‐weight polymeric liquids. Tube models of polymer dynamics and rheology are based on the idea that entanglements confine a chain to small fluctuations around a primitive path which follows the coarse‐grained chain contour. To establish the microscopic foundation for these highly successful phenomenological models, we have recently introduced a method for identifying the primitive path mesh that characterizes the microscopic topological state of computer‐generated conformations of long‐chain polymer melts and solutions. Here we give a more detailed account of the algorithm and discuss several key aspects of the analysis that are pertinent for its successful use in analyzing the topology of the polymer configurations. We also present a slight modification of the algorithm that preserves the previously neglected self‐entanglements and allows us to distinguish between local self‐knots and entanglements between distant sections of the same chain. Our results indicate that the latter make a negligible contribution to the tube and that the contour length between local self‐knots, Nlk is significantly larger than the entanglement length Ne. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 917–933, 2005
Investigation of organic condensed phoshates
Authors: Hlel F. , Thouvenot R. , Smiri L. 
Published: March 2005

AbstractPreparation, crystal structure and infra‐red absorption spectra are reported for a new organic salt of the cyclohexaphosphate, [C6H5(CH2)3NH3]6P6O18 · 2 H2O. The new compound crystallizes in the triclinic system (P$\bar 1$ space group) with Z = 2 and the following unit cell dimensions: a = 10.528(3), b = 19.183(2), c = 9.839(3) Å, α = 74.92(5), β = 117.48(6) and γ = 99.90(5)°. The structure was solved by using 6709 independent reflections down to R value of 0.039. The ring anion exhibits $\bar 1$ internal symmetry. Its main geometrical features are those commonly observed in the atomic arrangements of cyclohexaphosphates. The three dimensional cohesion of this atomic arrangement is maintained through H‐bonds between organic cations, water molecules and the external oxygen atoms of the P6O18–6 ring. The H‐bond interactions induce local distortions of the ring leading to the existence of three different types of phosphate tetrahedra.Solid‐state 31P magic‐angle‐spinning nuclear magnetic resonance (MAS NMR), performed at 162 MHz shows three isotropic resonances at –19.8, –22.6 and –24.5 ppm, confirming the non‐equivalence of the three PO4 groups. They are characterized by different chemical shift tensor parameters, which are in agreement with the local geometrical features of the tetrahedra. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evaluation by simulation of tests based on non‐linear mixed‐effects models in pharmacokinetic interaction and bioequivalence cross‐over trials
Authors: Panhard Xavière , Mentré France 
Published: March 2005

AbstractWe propose tests based on non‐linear mixed effects models (NLMEM) in pharmacokinetic interaction and bioequivalence cross‐over trials comparing two treatments or two formulations. To compare the logarithm of the area under the curve (AUC) using these models, two approaches are studied: in the first one, concentration data are analysed globally, with and without the estimation of a treatment effect; and in the second one, they are analysed separately in each treatment group with the estimation of the individual parameters. Four tests for comparison of the logarithm AUC between two treatment arms are studied: a likelihood‐ratio test (LRT), a Wald test and two tests, parametric and non‐parametric, comparing the individual Empirical Bayes (EB) estimates. These tests are adapted to the case of equivalence, except the LRT which does not have any simple extension. We evaluate by simulation of the type I error and the power for both comparison and equivalence tests. They are compared to the standard tests recommended by the FDA and the EMEA, based on non‐compartmental (NC) AUC. Trials for a usual PK model are simulated under H0 and several H1 using S‐plus software and analysed with the nlme function. Different configurations of the number of subjects (n=12, 24 and 40) and of the number of samples per subject (J=10, 5 and 3) are studied. The type I error α of LRT and Wald comparison test in the 5000 replications of interaction cross‐over trials is found to be 20.9 per cent and 21.7 per cent, respectively, in the original design (n=12, J=10), which is far superior to 5 per cent, and decreases when n increases. When n is fixed, α is found to increase with J. Power is satisfactory for both tests, after correction of the significance threshold. Results of EB and NC tests are similar with satisfactory powers and a type I error close to 5 per cent, except when J=3 for EB tests. Similar results are obtained for equivalence tests, except for EB and NC Student tests, which are not of a great interest. NC tests keep their place when the number of samples per subject J is large, but NLMEM seem useful for cross‐over studies performed in special populations where J limited; the evaluation by Monte‐Carlo simulations of empirical threshold seems however necessary because of the inflation of the type I error. Copyright © 2005 John Wiley Sons, Ltd.
Formalizing cardinality‐based feature models and their specialization
Authors: Czarnecki Krzysztof , Helsen Simon , Eisenecker Ulrich 
Published: March 2005

AbstractFeature modeling is an important approach to capture the commonalities and variabilities in system families and product lines. Cardinality‐based feature modeling integrates a number of existing extensions of the original feature‐modeling notation from Feature‐Oriented Domain Analysis. Staged configuration is a process that allows the incremental configuration of cardinality‐based feature models. It can be achieved by performing a step‐wise specialization of the feature model. In this article, we argue that cardinality‐based feature models can be interpreted as a special class of context‐free grammars. We make this precise by specifying a translation from a feature model into a context‐free grammar. Consequently, we provide a semantic interpretation for cardinality‐based feature models by assigning an appropriate semantics to the language recognized by the corresponding grammar. Finally, we give an account on how feature model specialization can be formalized as transformations on the grammar equivalent of feature models. Copyright © 2005 John Wiley & Sons, Ltd.
Regional and local patterns in plant species richness with respect to resource availability
Authors: Cornwell William K. , Grubb Peter J. 
Published: March 2005

The hump‐shaped relationship between plant species richness and productivity is a well‐established and important paradigm. While plot‐based species richness patterns on local scales have received much attention, little is currently known about species‐based patterns on a regional scale. Using Ellenberg's indicator values for 1802 plant species in central Europe, we assess the patterns in regional species richness with respect to light, water, and mineral nutrient availability – three variables that strongly influence productivity. The results of this analysis are compared to those of published studies on smaller scales leading to the following conclusions:On a regional scale in central Europe there is a hump‐shaped relationship between soil nutrient supply and plant species richness within a given biome.The peak in species richness for grasslands and wetlands occurs on nutrient‐poor soils, while the peak for forests is on nutrient‐rich soils.Gradients in plant productivity controlled by different variables (i.e. water, nutrients, or disturbance) have dissimilar effects on plant species richness.
Simulation of water flow and solute transport in free‐drainage lysimeters and field soils with heterogeneous structures
Authors: Abdou H. M. , Flury M. 
Published: March 2005

SummaryLysimeters are valuable for studying the fate and transport of chemicals in soil. Large‐scale field lysimeters are used to assess pesticide behaviour and radionuclide transport, and are assumed to represent natural field conditions better than laboratory columns. Field lysimeters are usually characterized by a free‐draining lower boundary. As a result, the hydraulic gradient is disrupted, and leachate cannot be collected until the bottom of the lysimeter becomes saturated. We compared heterogeneously structured, free‐drainage lysimeters and field soils with respect to water flow and solute transport. Numerical simulations were carried out in a two‐dimensional heterogeneous sandy soil under unsaturated water flow conditions with the CHAIN_2D code. Three different soil structures (isotropic, horizontal, and vertical) were generated, and Miller–Miller similitude was used to scale the hydraulic properties of the soil. The results showed that ponding occurs at the bottom of the lysimeter for the three soil structures and that it occurred faster and was more pronounced with the vertical structure (preferential flow effect). Breakthrough curves of a conservative solute (bromide) showed that solutes are moving faster in the field than in the lysimeters. Fewer differences between lysimeters and field soils were found with the horizontal soil structure than with the isotropic and vertical structures.
Study and comparison of two polishing methods for platinum–iridium surfaces, by means of three characterization techniques
Authors: Haidar Y , Tollens E , Silvestri Z , de Fornel F , Zerrouki C , Picard A , Pinot P 
Published: March 2005

Machining the surface of mass standards is still of great importance. This paper details a comparative study of the roughness of two plane surfaces of a platinum–iridium alloy (90% of platinum and 10% of iridium). Using the BIPM processes, the surfaces were initially machined on a lathe using diamond tools; in addition, one of these was manually polished with a diamond paste.Three techniques for surface characterization are used: shear-force microscopy (ShFM), optical roughness-meter and x-ray reflectometer. The first technique uses the shear-force interaction between the probe and the sample. The ShFM is part of a scanning near-field optical microscope that has the advantage of providing two images simultaneously, a topographical one and a near-field optical one. Only the topographic images will be presented in this paper; the results obtained in optical near-field will be the subject of another publication. To avoid any confusion, we will speak here of ShFM. The topographic images and their associated statistical and physical parameters, such as power spectral densities (PSDs), root-mean-square height, etc, are discussed in this paper. The PSDs of the surface are also determined experimentally from x-ray and visible light scattering measurements using angle-resolved scattering theory. This theory, which is well adapted for visible radiation, is extended to x-rays. The measurements made with the three instruments demonstrate that the two surfaces present a roughness of the same order of magnitude. However, the defects that contribute in a preponderant manner to their roughness spectrum do not belong to the same spatial bandwidth but depend on the polishing process.
A new Stroop‐like measure of inhibitory function development: typical developmental trends
Authors: Wright Ingram , Waterman Mitch , Prescott Helen , Murdoch‐Eaton Debbie 
Published: March 2005

Background:  Difficulties with inhibition are increasingly regarded as central to pathological behavioural and learning disorders in childhood. However, few measures are available to assist in the assessment of young children's inhibitory competence.Method:  A new, Stroop‐like measure of inhibitory function is described which was designed to be appropriate for use with children from 3 years of age. One hundred and fifty‐five school children aged between 3 and 16 years took part in a study to examine the developmental characteristics and behavioural correlates of task performance.Results:  The task appears to provide a robust measure of inhibitory function across the age range, 3 to 16 years. Furthermore, the animal‐stroop task appears to identify those at risk of hyperactive symptomatology within a school‐based sample.Conclusions:  The clinical and developmental applications of this new measure are discussed.
Psychosocial correlates of depressive symptoms among 12–14‐year‐old Norwegian adolescents
Authors: Sund Anne Mari , Larsson Bo , Wichstrøm Lars 
Published: March 2005

Background:  The aim of the study was to examine the relationships between various psychosocial factors and depressive symptoms in early adolescence.Methods:  A representative sample of 2,465 12–14‐year‐old adolescents comprising 50.8% girls and 49.2% boys, with a mean age of 13.7 years, was recruited in two counties in Norway. The participation rate was 88.3%. Depressive symptoms were measured by the Mood and Feelings Questionnaire (MFQ).Results:  Correlations between the total sum of stressful events/daily hassles and the total sum of MFQ were moderately high, rs=.49 and rs=.53, respectively. Depressive symptoms were more strongly correlated with school‐related stress among boys than girls, whereas the correlation between daily hassles and depressive symptoms was higher for girls than boys. The results of univariate analyses showed significantly higher mean total MFQ scores among adolescents not living with both natural parents, those who had moved more than twice and those with more than 3 siblings or having fewer than 2 close friends. Further, adolescents from Third World societies and adopted adolescents, those from lower SES groups, having unemployed parents or living in coastal areas had higher mean depressive symptom scores. The results of multiple regression analyses yielded the following six significant predictors of total MFQ scores in order of importance: Sum of daily hassles and sum of stressful life events, gender, number of friends, ethnicity and mother's employment status. Altogether, these variables accounted for 43% of the total variance in MFQ scores.Conclusions:  It is concluded that these psychosocial predictors should be addressed when assessing depressive symptoms in early adolescence. The findings of the study are discussed in view of previous research in the field and their clinical significance.
Status of climacteric symptoms among middle‐aged to elderly Japanese women: Comparison of general healthy women with women presenting at a menopausal clinic
Authors: Ikeda Toshiyuki , Makita Kazuya , Ishitani Ken , Takamatsu Kiyoshi , Horiguchi Fumi , Nozawa Shiro 
Published: March 2005

AbstractAim: To examine the status and characteristics of climacteric symptoms reported by generally healthy middle‐aged to elderly women in Japan, those living in Saitama Prefecture were surveyed .Methods: The subjects comprised 398 women ranging in age from 40 to <60 years (mean age, 50.5 years). Climacteric symptoms were objectively assessed using the Keio questionnaire. The total scores obtained for the 40 symptoms were used to calculate symptom prevalence and severity.Results: (i) The most frequent symptom was poor memory, reported by 88.7% of the women. (ii) Lumbar‐sacral back pain was rated as a severe symptom by the highest percentage of women (15.3%). (iii) The prevalence and severity of poor memory and lumbar‐sacral back pain did not differ with menopausal status. (iv) Hot flashes and sweats were slightly higher in peri‐ and early postmenopausal women than in premenopausal women.Conclusions: The present study showed that healthy women who do not consult physicians because of climacteric symptoms are primarily concerned with age‐related symptoms, such as poor memory, loss of hair, and forgetfulness.
Rapid incorporation of carbon from fresh residues into newly formed stable microaggregates within earthworm casts
Authors: Bossuyt H. , Six J. , Hendrix P. F. 
Published: March 2005

SummaryEarthworms play an important role in protecting carbon in the soil, but the exact influence of their activity on the distribution and protection of C is still poorly understood. We investigated the effect of earthworms on the formation of stable microaggregates inside newly formed macroaggregates and the distribution of C in them. We crushed (< 250 µm) soil, and subjected it to three treatments: (i) soil + 13C‐labelled residue + earthworms (these added after 8 days' incubation), (ii) soil + 13C‐labelled residue, and (iii) control (no additions), and then incubated it for 20 days. At the end, we measured the aggregate size distribution, total C and 13C, and we isolated microaggregates (53–250 µm) from macroaggregates (> 250 µm) formed. The 13C in fine particulate organic matter between and within the microaggregates was determined. Earthworms helped to form large macroaggregates (> 2000 µm). These large macroaggregates contained four times more stable microaggregates than those from samples without earthworms. There was more particulate organic matter within and between microaggregates in macroaggregates in the presence of earthworms. The larger amounts of organic matter inside stable microaggregates in casts than in bulk soil after 12 days of incubation (140 mg 13C kg−1 soil compared with 20 mg 13C kg−1 soil) indicates that these microaggregates are formed rapidly around freshly incorporated residues within casts. In conclusion, earthworms have a direct impact on the formation of stable microaggregates and the incorporation of organic matter inside these microaggregates, and it seems likely that their activity is of great significance for the long‐term stabilization of organic matter in soils.
High‐dose vitamin E supplementation does not diminish ribavirin‐associated haemolysis in hepatitis C treatment with combination standard α‐interferon and ribavirin
Authors: Saeian K. , Bajaj J. S. , Franco J. , Knox J. F. , Daniel J. , Peine C. , McKee D. , Varma R. R. , Ho S. ,   Midwest Hepatitis Study Group
Published: March 2005

SummaryBackground: Ribavirin is associated with haemolytic anaemia. Antioxidants have been reported to decrease severity of this anaemia.Aim: To determine effect of vitamin E supplementation on ribavirin‐associated haemolysis in chronic hepatitis C treated with standardα‐interferon and ribavirin.Methods: Fifty‐one naive chronic hepatitis C patients were randomized to receive eitherα‐interferon/ribavirin therapy (control) or therapy plus vitamin E 800 IU b.d. with 24‐week follow‐up. Alanine aminotransferase ALT, haemoglobin and reticulocyte percentage were monitored. Symptoms and health‐related quality of life were also monitored at each visit.Results: Forty‐seven subjects were treated (27 vitamin E /20 controls). Thirteen withdrew because of adverse effects or non‐compliance. Groups were similar in demographics, genotype and baseline lab indices. Comparison with baseline, treatment and follow‐up values showed a significant haemoglobin and ALT reduction in both groups. There was no significant difference in haemoglobin and reticulocyte percentage between groups. Sustained viral response was not significantly different between vitamin E (11/18) and control (6/16) groups. Three patients required ribavirin dose‐reduction in the vitamin E group compared with two controls. Health‐related quality of life during and end‐of‐treatment was not different between groups.Conclusions: Vitamin E supplementation alone during standardα‐interferon and ribavirin therapy does not appear to diminish ribavirin‐associated haemolysis.
Mobilization of dissolved organic matter, aluminium and iron in podzol eluvial horizons as affected by formation of metal‐organic complexes and interactions with solid soil material
Authors: Jansen B. , Nierop K. G. J. , Verstraten J. M. 
Published: March 2005

SummaryInteractions with dissolved organic matter (DOM) are generally believed to play a crucial role in the translocation of Al and Fe in acid sandy soils. Binding of Al and Fe to DOM affects their mobility in soils by altering sorption equilibria of charged sites on solid soil material, inducing precipitation of organo‐metallic complexes and preventing the formation of inorganic Al and Fe phases. The relative importance of the different processes, especially with respect to the translocation of Al, Fe and organic matter in podzols, remains unresolved. We determined the effect of the presence of solid soil material from the eluvial (AhE and AE, respectively) horizons of a Fimic Anthrosol and a Haplic Podzol on the metal‐to‐organic carbon (M/C) ratio in solution and the formation of dissolved organic Al and Fe complexes. Furthermore, we assessed the resulting influence on the mobilization of Al, Fe and DOM. Even under considerable metal loading, the M/C ratios and ‘free’ metal fractions in solution remained low and relatively constant, due to an apparent buffering by the solid phase and the formation of organo‐metal complexes in solution. The M/C ratios remained so low that significant precipitation of organo‐metal complexes due to saturation with metals was not found. The apparent buffering by the solid phase can be explained by a strong release of organic matter from solid soil material and adsorption of non‐complexed Al and Fe on solid organic matter upon metal addition. Adsorption of organo‐metal complexes most likely played only a minor role. The observations confirm the expected mobilization of Al, Fe and DOM in eluvial horizons and seem to indicate that even under fluctuating input of Al, Fe and DOM the soil solution will have a constant composition with respect to M/C ratios and percentage of Al and Fe present in dissolved organo‐metal complexes.
Emissions of N2O from soils during cycles of freezing and thawing and the effects of soil water, texture and duration of freezing
Authors: Teepe R. , Vor A. , Beese F. , Ludwig B. 
Published: March 2005

SummaryFreezing and thawing influence many physical, chemical and biological processes in soils, including the production of trace gases. We studied the effects of freezing and thawing on three soils, one sandy, one silty and one loamy, on the emissions of N2O and CO2. We also studied the effect of varying the water content, expressed as the percentage of the water‐filled pore space (WFPS). Emissions of N2O during thawing decreased in the order 64% > 55% > 42% WFPS, which suggests that the retardation of the denitrification was more pronounced than the acceleration of the nitrification with increasing oxygen concentration in the soil. However, emissions of N2O at 76% WFPS were less than at 55% WFPS, which might be caused by an increased ratio of N2/N2O in the very moist conditions. The emission of CO2 was related to the soil water, with the smallest emissions at 76% WFPS and largest at 42% WFPS. The emissions of CO2 during thawing exceeded the initial CO2 emissions before the soils were frozen, which suggests that the supply of nutrients was increased by freezing. Differences in soil texture had no marked effect on the N2O emissions during thawing. The duration of freezing, however, did affect the emissions from all three soils. Freezing the soil for less than 1 day had negligible effects, but freezing for longer caused concomitant increases in emissions. Evidently the duration of freezing and soil water content have important effects on the emission of N2O, whereas the effects of texture in the range we studied were small.