bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vergleichende Untersuchungen zur Pflanzenverfügbarkeit von Phosphat aus verschiedenen P‐Recycling‐Produkten im Keimpflanzenversuch
Authors: Römer Wilhelm 
Published: December 2006

AbstractDie Weltreserven an Rohphosphaten hoher Qualität und moderater Abbaukosten reichen noch für ca. 90 Jahre. Daraus leitet sich die Notwendigkeit des Phosphat (P)‐Recyclings aus P‐haltigen Abfällen ab. In Deutschland fallen jährlich 2,4 × 106 t Trockenmasse Klärschlamm und über 600.000 t Abfälle tierischen Ursprungs an. Mit dem daraus recycelten P könnte der größte Teil der bisherigen P‐Mineraldünger ersetzt werden. Verlässliche Daten über die Pflanzenverfügbarkeit des P liegen für viele Produkte des P‐Recyclings jedoch noch nicht vor. In einem 21‐tägigen Keimpflanzenversuch (Applikation von 20 mg P (300 g Quarzsand)–1 in 10 cm × 10 cm × 6 cm großen Plastikgefäßen; Aussaat von 100 Roggenkörnern; Einstellung auf 65% der max. Wasserkapazität) wurden daher 26 P‐Verbindungen überprüft (u. a. verschiedene Calcium‐, Magnesium, Eisen‐, Aluminium‐, Ammonium‐ bzw. Magnesium‐Ammonium‐Phosphate, Thomasphosphate). Als Kontrolle wurde eine Variante ohne P‐Gabe eingesetzt. Die Netto‐P‐Aufnahme (P‐Menge in Sprossen und Wurzeln minus P‐Menge in den Kontrollpflanzen) ergab Auskunft über die P‐Verfügbarkeit für die Pflanzen. Die P‐Aufnahme aus den Ca‐Phosphaten sank erwartungsgemäß vom primären Ca‐Phosphat (als Referenz gleich 100 % gesetzt) bis zum Ca‐Apatit auf 10 %. Aus primärem, sekundärem und tertiärem Mg‐Phosphat wurden P‐Mengen ähnlich denen aus dem primären Ca‐Phosphat aufgenommen. Das gleiche galt für die P‐Aufnahme aus Ammonium‐Phosphat und Magnesium‐Ammonium‐Phosphat (Struvit). Thomasphosphate und Sinterphosphate zeigten nur etwa 42 bis 65 % der P‐Verfügbarkeit von primärem Ca‐Phosphat. Insbesondere Fe‐Phosphat versagte völlig als P‐Quelle. Als agronomisch interessante P‐Recyclingprodukte erwiesen sich die Magnesium‐ sowie die Magnesium‐Ammonium‐Phosphate. Zur weiteren Absicherung dieser Ergebnisse müssen diese Produkte in verschiedenen Böden sowohl in Gefäß‐ als auch Feldversuchen überprüft werden.
A semi‐analytical model for solute transport in layered dual‐porosity media
Authors: Ilsemann Jan , van der Ploeg Rienk R. , Horton Robert , Hermsmeyer Dirk 
Published: December 2006

AbstractThe vulnerability of groundwater from chemical leaching through soil is a concern at some locations. Because measurements are laborious, time‐consuming, and expensive, simulation models are frequently used to assess leaching risks. But the significance of simulated solute movement through a layered soil is questionable if vertical homogeneity of physical soil properties has been assumed.In the present study, a semi‐analytical model for solute leaching in soils is presented. The model is relatively simple, but it does account for soil layers having different physical properties. The model includes the mobile‐immobile model (MIM) to describe one‐dimensional (1‐D) nonequilibrium, transient solute transport under steady‐state flow conditions. The MIM is rewritten as a second‐order differential equation and solved by a numerical scheme. Differing from fully analytical or fully numerical solutions, the new approach solves the differential equation numerically with respect to time and analytically with respect to distance.Numerical experiments for a single layered soil profile show that the semi‐analytical solution (SA‐MIM) is numerically stable for a wide range of parameter values. The accuracy of SA‐MIM predictions is comparable to that of analytical solutions. Numerical experiments for a multilayered profile indicate that the model correctly predicts effluent curves from finite layered soil profiles under steady‐state flow conditions.The SA‐MIM simulations with typical parameter values suggest that neglecting vertical heterogeneity of flow paths in a layered soil can lead to inaccurate prediction of soil‐solute leaching. The quality of predictions is generally improved if parameter estimates for the different soil layers are considered. However, the mobile‐immobile‐parameter estimates obtained in a number of previous studies may not be transferable to a field situation that is characterized by a slow and steady flow of water. Further field experiments to determine mobile‐immobile parameters under such conditions are desirable.
Measurement modeling of soil‐water dynamics evapotranspiration of drained peatland soils
Authors: Schwärzel Kai , Šimůnek Jirka , van Genuchten Martinus Th. , Wessolek Gerd 
Published: December 2006

AbstractNatural peat soils serve as important sinks for nutrients, organic components, and water. Peat soils can pose major environmental problems when they are drained for agricultural production, which may change their role in the landscape from a sink to a source. To successfully restore and conserve peat soils, it is important to understand the soil‐moisture dynamics and water demand of drained peat soils for different climate and groundwater conditions. For this purpose, we conducted a series of lysimeter experiments with peat soils subject to different groundwater levels. Evapotranspiration (ET) rates and upward capillary fluxes in peat soils under grass were measured, while TDR probes and tensiometers were used to monitor the soil‐water dynamics in the lysimeter during the growing season. The lysimeter data were simulated using an extended version of HYDRUS‐1D to enable ET calculations using the Penman‐Monteith equation. A physically based approach was tested to predict the canopy resistance as a function of the average pressure head of the soil root zone. The numerical simulations closely followed the observed soil‐moisture dynamics in the lysimeter and were consistent with measured differences in ET rates for different groundwater levels. Besides average climate conditions, the effects of extreme dry and wet weather conditions on ET and groundwater recharge during the growing season were evaluated using the calibrated numerical model for different groundwater levels. Evapotranspiration rates during dry years depended very much on upward capillary flow from the water table and hence on the soil hydraulic properties. During wet years, however, ET was controlled mostly by the evaporative demand of the atmosphere, and much less by the soil hydraulic properties.
Microbial biomass activities in urban soils in two consecutive years
Authors: Lorenz Klaus , Kandeler Ellen 
Published: December 2006

AbstractEcological soil functions are protected in Germany. Thus, for the sustainable use of urban soil resources data on the function of soils to serve as a habitat are required. Soil microbial biomass and activities were studied in two surface horizons in two consecutive years at nine sites in Stuttgart, Germany, differing in land use. Microbial biomass (chloroform‐fumigation extraction, substrate‐induced respiration) and microbial activities (potential N mineralization, potential ammonium oxidation, and enzyme activities of dehydrogenase, urease, arylsulfatase, and phosphatase) were determined in 2001 and 2002. DIN/ISO standard methods were applied as far as they were available. Furthermore, soil chemical properties were determined in the 2001‐samples. Large differences in chemical and microbiological properties among surface horizons were found. Concentrations of microbial biomass and microbial activities were, however, often comparable to agricultural or forest surface soils. The lowest microbial biomass and activities were observed at a highly disturbed railway area where vegetation was missing and total organic C (TOC) had been altered by anthropogenic organic particles. In contrast, microorganisms were promoted at vegetated sites and where organic impurities were negligible. As TOC was altered by obscure organic matter, total N (TN) and not TOC closely correlated with soil microbiological properties. Biomass and activity generally decreased with depth, but mixing of organic matter resulted in more uniform depth distribution of microbial properties in one garden soil. In 2002, microbial biomass and activity were often lower compared to 2001, but interpretation of this difference hampered as the number of samples taken was probably not sufficient to address the spatial variability in soil properties. Additional studies are needed to develop simple and cost‐effective procedures for the evaluation of ecological quality of urban soils by combined efforts of city planners and soil scientists.
Performance differences across strategic groups: an examination of financial market‐based performance measures
Authors: Pandian J. Rajendran , Thomas Howard , Furrer Olivier , Bogner William C. 
Published: December 2006

Abstract

One of the more interesting issues in the strategic management field is the question of whether intra‐industry performance differences exist, particularly across strategic groups. Most of the existing studies have used accounting measures of performance despite the documented weaknesses of such measures. This paper examines whether financial market‐based measures of performance are superior to accounting‐based measures in identifying performance differences across strategic groups.

Hypotheses are tested on data from an existing sample of firms in the US pharmaceutical industry. The empirical results indicate that performance differences are more likely to exist across strategic groups when financial market performance measures are used. Suggestions for further refinements are made and limitations of the study are discussed.

Copyright © 2006 John Wiley & Sons, Ltd.
Business scope and competitive differentiation: a study of strategy consistency
Authors: Pehrsson Anders 
Published: December 2006

Abstract

Obstacles to strategy implementation and change are often due to limited consistency between the choices that a firm has to make regarding business scope and differentiation.

The purpose of this paper is to identify relationships between business scope and competitive differentiation in industrial firms. It reports on managerial perceptions within a sample of business units of Swedish manufacturing firms in Germany, the United Kingdom and the United States.

The study found that standardized products offered to just a few market segments are associated with an emphasis on product differentiation but that this strategy causes negative performance effects. In contrast, penetration of many segments is associated with customer flexibility attributes, yielding positive results.

The study contributes to our understanding of strategy consistency by establishing associations between business scope and competitive differentiation. Management advice is presented.

Copyright © 2006 John Wiley & Sons, Ltd.
Two‐sided surface roughness and hydrodynamic pressure distribution in lubricating films
Authors: Burstein Leonid 
Published: December 2006

AbstractA spatial one‐dimensional time‐dependent mathematical model of roughened sliding surfaces with a sinusoidal profile was developed and applied in the context of their fluid lubrication. The opposing surfaces have identical average roughness and wavelength characteristics. The hydrodynamic pressure distribution equation is derived for different peak‐hollow numbers and roughness depths. Matlab (the Mathworks, Inc., Natick, MA, USA) calculations show a significant effect of roughness with a small number of peak‐hollow waves on the above parameter. The effect becomes less significant as the number of waves increases, and practically vanishes between the 1000–40000 level at all roughnesses from 0.1 to 0.4. Copyright © 2006 John Wiley and Sons, Ltd.
Gradient Density Grafted Polymers on Ground Tire Rubber Particles by Atom Transfer Radical Polymerization
Authors: Coiai Serena , Passaglia Elisa , Ciardelli Francesco 
Published: December 2006

AbstractSummary: The graft polymerization of styrene and (meth)acrylic monomers via ATRP from cross‐linked rubber particles, produced by recycled tires (“ground tire rubber”, GTR), is reported. GTR particles, obtained by cryogenic grinding process, still contain CC unsaturations on the surface, which were first oxidized to hydroxyl groups and then modified by reaction with 2‐bromoisobutyryl bromide to serve as ATRP macroinitiators. Graft polymerizations were carried out using CuBr/CuBr2/N,N,N′,N″,N″‐pentamethyldiethylenetriamine as catalytic system in bulk or in anisole at high temperature. The grafted particles were analyzed by ATR‐IR (spectra were recorded on particles surface and cross‐sectional slices), TGA, SEM and X‐ray microanalysis.Arrangement of surface‐grafted polymer assemblies along the particles section.magnified imageArrangement of surface‐grafted polymer assemblies along the particles section.
Functionalization and Linking Chemistry of Poly(styryl)lithium with 1,3‐Butadiene Diepoxide
Authors: Quirk Roderic P. , Contractor Asfiya , Polce Michael J. , Wesdemiotis Chrys 
Published: December 2006

AbstractSummary: The reaction of excess poly(styryl)lithium ($\overline M _{\rm n}$ = 1 400 g · mol−1) with 1,3‐butene diepoxide proceeds efficiently to produce a coupled product with two in‐chain hydroxyl groups. The pure coupled, functionalization product was isolated in quantitative yield by silica gel column chromatography. This product was characterized by 1H and 13C NMR spectroscopic analyses, as well as MALDI‐TOF mass spectrometry. The DEPT 13C NMR spectrum showed that a disecondary 1,2‐diol unit was present, consistent with attack of PSLi on the least‐substituted, methylene carbons of 1,3‐butadiene diepoxide. The MALDI‐TOF mass spectrum of the purified product exhibited only one distribution with monoisotopic peaks corresponding to the coupled, dihydroxy‐functionalized polystyrene.MALDI‐TOF mass spectrum of the purified, in‐chain, hydroxyl‐functionalized polystyrene and the reaction of PSLi with 1,3‐butadiene diepoxide.magnified imageMALDI‐TOF mass spectrum of the purified, in‐chain, hydroxyl‐functionalized polystyrene and the reaction of PSLi with 1,3‐butadiene diepoxide.
Kerbgrundkonzepte für die schwingfeste Auslegung von Aluminiumschweißverbindungen am Beispiel der naturharten Legierung AlMg4,5Mn (AW‐5083) und der warmausgehärteten Legierung AlMgSi1 T6 (AW‐6082 T6)
Authors: Morgenstern C. , Hanselka H. 
Published: December 2006

AbstractÖrtliche Kerbspannungskonzepte auf Basis von werkstoff‐ und gefügespezifischen Kennwerten, wie das Mikrostützwirkungskonzept, weisen Schwächen in der praktischen Anwendbarkeit auf. Anhand von Schwingfestigkeitsergebnissen mit verschiedenen MIG‐Aluminiumschweißverbindungen der Legierungen AlMg4,5Mn (AW‐5083) und AlMgSi1 T6 (AW‐6082 T6) unter wechselnder und schwellender Beanspruchung wird das Mikrostützwirkungskonzept dem Kerbspannungskonzept mit einem fiktiven Ersatzradius gegenübergestellt. Die Auswertung der Ergebnisse zeigt, dass das örtliche Kerbspannungskonzept mit einem fiktiven Ersatzradius von rf = 1,0 mm auf Aluminiumschweißverbindungen mit Dicken von t ≥ 5 bis 25 mm angewendet werden kann, wobei es unabhängig von der Legierung und der Schweißnahtgeometrie (Stumpfstoß mit und ohne Wurzelspalt, Quersteife) ist. Es werden Master‐Wöhlerlinien für verschiedene Spannungsverhältnisse, R = ‐1, 0 und 0,5, vorgeschlagen, die eine Berücksichtigung sowohl von Eigenspannungen als auch belastungsinduzierten Mittelspannungen zulassen. Darüberhinaus wird aus den Ergebnissen der Vorschlag von Δσ = 70 MPa als FAT‐Klasse für das IIW‐Regelwerk abgeleitet.
Conformational and tautomeric eccentricities of 2‐acetyl‐1,8‐dihydroxynaphthalenes
Authors: Hansen Poul Erik , Kamounah Fadhil S. , Hansen Bjarke K. V. , Spanget‐Larsen Jens 
Published: December 2006

AbstractTautomerism in aromatic systems with oxygen substitutents is rare. This is investigated in 2‐acetyl‐1,8‐dihydroxy‐3,6‐dimethylnaphthalene (1) and in 2,7‐diacetyl‐1,8‐dihydroxy‐3,6‐dimethylnaphthalene (2). The tautomeric nature of 2‐acetyl‐1,8‐dihydroxy‐3,6‐dimethylnaphthalene is supported by long‐range hydrogen–hydrogen coupling between the OH‐1 and the OH‐8 and by the isotope effects on 13C caused by deuteration at the CH3CO methyl group. Compound 2 participates in a degenerate equilibrium between two equivalent nonsymmetrical rotamers (2A and 2B), each having two intramolecular O···HO hydrogen bonds: one involving an acetyl oxygen and the neighboring hydroxyl group, and the other between the oxygen centers at positions 1 and 8. In addition, each rotamer is involved in a tautomeric equilibrium, with a structure having an OH‐substituted exocyclic double bond (2AT or 2BT).DFT calculations for a large set of compounds highlight the factors controlling the unusual rotational and tautomeric behaviors. A very important factor seems to be the repulsive interaction between the O‐1 and O‐8 centers, which is modulated by formation of an OH‐1···O‐8 or OH‐8···O1 hydrogen bond. Steric interactions, mesomeric release of electrons from the oxygen at position 8, and a strong OH···O···C hydrogen bond are other factors.Solid‐state 13C NMR spectra of 2,7‐diacetyl‐1,8‐dihydroxy‐3,6‐dimethylnaphthalene at different temperatures demonstrated no averaging in the solid, whereas partially deuterated 2‐acetyl‐1,8‐dihydroxy‐3,6‐dimethylnaphthalene showed an isotope effect at C‐1 of 1.5 ppm, indicating tautomerism in the solid state. Copyright © 2006 John Wiley & Sons, Ltd.
15N NMR study of substituted 2‐(phenylamino)‐5‐phenyl‐1,3,4‐oxadiazoles
Authors: Gierczyk Błażej , Nowak‐Wydra Barbara , Grajewski Jakub , Zalas Maciej 
Published: December 2006

AbstractSubstituted 2‐(phenylamino)‐5‐phenyl‐1,3,4‐oxadiazoles were studied by 15N NMR spectroscopy. All signals were assigned on the basis of HMQC and HMBC experiments. Chemical shifts values were correlated with empirical Hammett parameters as well as with calculated electron densities and chemical shieldings. Copyright © 2006 John Wiley & Sons, Ltd.
1H and 13C NMR studies of 2‐functionalized 5‐(methylsulfonyl)‐1‐phenyl‐1H‐indoles
Authors: Cruz‐López Olga , Gallo Miguel A. , Espinosa Antonio , Campos Joaquín M. 
Published: December 2006

AbstractThe 1H and 13C NMR resonances of thirty 2‐functionalized 5‐(methylsulfonyl)‐1‐phenyl‐1H‐indoles were assigned completely and unequivocally using the concerted application of one‐ and two‐dimensional experiments (DEPT, gs‐HMQC and gs‐HMBC). Finally, the influence of the 2‐substituent of 5‐(methylsufonyl)‐1‐phenyl‐1H‐indoles on the carbon atoms of the indole moiety was estimated. Copyright © 2006 John Wiley & Sons, Ltd.
Is spinal cord isolation a good model of muscle disuse?
Authors: Roy R. R. , Zhong H. , Khalili N. , Kim S. J. , Higuchi N. , Monti R. J. , Grossman E. , Hodgson J. A. , Edgerton V. R. 
Published: December 2006

AbstractThe patterns of normal daily activity that are required to maintain normal skeletal muscle properties remain unknown. The present study was designed to determine whether spinal cord isolation can be used as a reliable experimental model of neuromuscular inactivity, that is, as a baseline for the absence of activity. Electromyograms (EMGs) were recorded from selected hindlimb muscles of unanesthetized rats over 24‐hour periods before and 7, 30, 60, and 90 days after surgical isolation of the lumbar spinal cord. Our data indicate that some rat slow muscle fibers pre‐surgery were activated for less than 3 hours per day. Spinal cord isolation (SI) reduced the mean daily integrated EMG (IEMG) and daily EMG duration in the primary slow extensor muscle (soleus) to <1% of control, and in the primary fast extensor muscles [medial gastrocnemius (MG) and vastus lateralis (VL)] to <2% of control. These parameters were decreased to <8% and 3% of control, respectively, in a primary fast flexor muscle, the tibialis anterior (TA). From 30 to 90 days post‐SI, the mean amplitudes of the spontaneous EMG bursts were relatively normal in the soleus, increased ∼2‐fold in the MG and VL, and increased ∼4‐fold in the TA. Some evidence of the normal antagonistic flexor–extensor relationship was apparent in the brief periods of recorded activity post‐SI. These results indicate that SI eliminates nearly all of the normal EMG activity in the hindlimb muscles in the presence of relatively normal muscle innervation and functional intraspinal neural circuitry. Muscle Nerve, 2006
Improvement in fetal DNA extraction from maternal plasma. Evaluation of the NucliSens Magnetic Extraction system and the QIAamp DSP Virus Kit in comparison with the QIAamp DNA Blood Mini Kit
Authors: Clausen Frederik Banch , Krog Grethe Risum , Rieneck Klaus , Dziegiel Morten Hanefeld 
Published: December 2006

AbstractObjectivePrenatal diagnostic assays have been developed using free fetal DNA circulating in the maternal blood of pregnant women. Efficient DNA extraction is crucial for a robust analysis. To improve fetal DNA yield, we tested two manual extraction methods—the NucliSens Magnetic Extraction (NMAG) system and the QIAamp DSP Virus Kit (QDSP)—against our current standard method, the widely used QIAamp DNA Blood Mini Kit (QDNA).MethodsThe fetal DNA yield of the two extraction systems was evaluated using the RHD exon 7 as target in DNA extracts of 75 plasma samples from pregnant RhD‐negative women, known to have given birth to RhD‐positive infanto. The total DNA yield was evaluated in 23 samples, targeting GAPDH.ResultsThe fetal DNA yield was improved by a mean factor of 1.7 using the NMAG system, and improved by a mean factor of 1.5 using the QDSP.The total DNA yield was improved by a mean factor of 2.3 using the NMAG system, and by a mean factor of 1.3 using the QDSP.ConclusionBoth extraction systems tested were superior to our standard with regard to DNA yield. This improvement may have a great impact on the success of genotyping in early pregnancy. Copyright © 2007 John Wiley & Sons, Ltd.
Fetal anomaly scan potentially will replace routine AFAFP assays for the detection of neural tube defects
Authors: Kooper Angelique J. A. , de Bruijn Dagmar , van Ravenwaaij‐Arts Conny M. A. , Faas Brigitte H. W. , Creemers Johan W. T. , Thomas Chris M. G. , Smits Arie P. T. 
Published: December 2006

AbstractObjectivesIntroduction of the second‐trimester fetal anomaly scan and the decision to offer this scan to every woman in the 18th–22nd week of pregnancy necessitates a re‐evaluation of the diagnostic value of the measurement of α‐fetoprotein (AFP) concentrations in the amniotic fluid (AF) for the detection of neural tube defects (NTDs).MethodsIn this study of 6501 women who underwent amniocentesis, amniotic fluid AFP (AFAFP) concentrations were measured. The women were divided into three categories: group I, without any increased risk of fetal NTD (N = 6188); group II, with an increased risk of fetal NTD (N = 258); and group III, with a clinically diagnosed fetal NTD with known AFAFP concentrations (N = 55).ResultsIn 27 women of group I (0.4%), the MoM (multiple of the median) level was > 2.5 times the median AFP concentration for the corresponding gestational age, and in two fetuses this was related to NTD. In two pregnancies of group II (0.8%), an increased AFAFP was related to NTD. In group III, 44 of the 55 (80%) samples had an increased AFAFP.ConclusionIn the near future, it is likely that imaging will replace AFAFP assays for the detection of fetal NTDs because high quality ultrasound imaging will detect NTDs accurately. Copyright © 2007 John Wiley & Sons, Ltd.