bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical simulation of stirred liquid‐liquid systems
Authors: Schlauch Sonja
Published: January 2007

The numerical simulation of drop size distributions in stirred liquid‐liquid systems requires, on one hand, the simulation of the flow field in the stirred tank and, on the other hand, the calculation of the population dynamical processes. These processes, in the considered application coalescence and breakage, describe how the number and the sizes of the drops in the dispersed phase change with time.

In the presented approach, the (Reynolds‐averaged) Navier‐Stokes equations (with k ‐ε turbulence model), describing the turbulent flow in the stirred tank, are solved with a CFD code and the population balance equation, accounting for coalescence and breakage of the drops, is simulated with a population balance solver. The coupling of the two solvers is realized as a oneway coupling, i. e. the results of the CFD simulation are used for the calculation of the population dynamical processes. We will explain how the coupling can be realized, motivate why this type of coupling was chosen, and present simulation results. However, we will also discuss arising problems and risks of simulator coupling. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Performance and limitations of the unsteady RANS approach
Authors: Schwarze Rüdiger , Obermeier Frank
Published: January 2007

Turbulent flows in complex geometries often exhibit an oscillating behavior of large coherent structures, even in the case of steady state boundary conditions. Recently, numerous efforts have been made to resolve these oscillations by means of numerical simulations. Unfortunately, large‐eddy simulations are often very time‐ and memory‐consuming in the case of complex flows. Therefore, the unsteady RANS (URANS) approach is an attractive alternative, especially when numerical simulations are used as a design and optimization tool.

Here, two complex flow situations are presented, the tundish flow and a jet in a crossflow. For these flows, relationships between the Strouhal number and important flow parameters are known from experiments. In the paper, URANS models are applied to resolve those relationships also numerically. The evaluation of the numerical results demonstrates the abilities and the limitations of the URANS approach when resolving the dynamics of large coherent structures in complex flows. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of the Propagation Direction for an Acoustic Wave Interacting with a Turbulent Premixed Flame
Authors: Shalaby Hemdan , Thévenin Dominique
Published: January 2007

We investigate in this work the conditions leading to amplification or damping of a planar, Gaussian acoustic wave interacting with a CO/H2/Air turbulent premixed flame. We examine in particular the influence of the direction of propagation. In a first case the acoustic wave is coming from the right direction (starting in burnt gas zone), while it propagates from the left direction (starting in fresh gas zone) in the second case. This investigation is based on fully compressible Direct Numerical Simulation (DNS) results. Chemical processes are computed using a complete reaction scheme and accurate transport properties are taken into account. A local version of the classical Rayleigh's criterion is used to analyze the results, based on the single assumption that the celerity of sound is independent of time and only function of the spatial coordinates. We observe that, after the interaction, the wave is wrinkled leading to a non‐planar geometry, similar to that of the initial flame front. For both cases the heat release fluctuation is concentrated in very small zones, associated either with positive or negative values. Rayleigh's criterion is then used to localize large positive and negative values (amplification resp. damping conditions). This criterion shows that wave amplification occurs only inside well‐located small zones in the two cases. The propagation direction has no influence on these results, confirming that amplification or damping is mainly controlled by a coupling process between pressure and heat release fluctuations through the chemical reactions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evaporation and condensation of a binary mixture of vapors
Authors: Yasuda Shugo , Takata Shigeru , Aoki Kazuo
Published: January 2007

Half‐space problem of evaporation and condensation of a binary mixture of vapors is investigated on the basis of the linearized Boltzmann equation for hard‐sphere molecules with the complete condensation condition. The problem is analyzed numerically by a finite‐difference method, in which the complicated collision integrals are computed by the extension of the method proposed by Y. Sone, T. Ohwada, and K. Aoki [Phys. Fluids A 1, 363 (1989)] to the case of a gas mixture. As a result, the behavior of the mixture is clarified not only at the level of the macroscopic quantities but also at the level of the velocity distribution function. In addition, accurate formulas of the temperature, pressure, and concentration jumps caused by the evaporation and condensation are constructed for arbitrary values of the concentration of the background reference state by the use of the Chebyshev polynomial approximation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling free surfaces in oscillating pipe flows
Authors: Adler Katrin , Schwarze Rüdiger , Chaves Humberto
Published: January 2007

An oscillating pipe flow with a free surface is investigated numerically and experimentally. The pipe diameter is 12mm. Due to this small diameter capillary forces play an important role. Therefore special attention has to be paid to the flow field near the free surface. The numerical model is based on the fundamental flow equations. The free surface is resolved according to the volume‐of‐fluid method. The model equations are solved on a moving grid. In the experiment, pictures of the flow field are taken near the free surface. The effects occuring near the interface will be presented here. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimentelle Untersuchung des Temperaturfelds in einem Extruder
Authors: Conzen Carsten , Wünsch Olaf
Published: January 2007

Extruder werden im Maschinenbau und in der Verfahrenstechnik zur Förderung und Homogenisierung von hochviskosen Flüssigkeiten, wie z. B. Kunststoffschmelzen verwendet. Diese besitzen neben der temperatur‐ und schergeschwindigkeitsabhängigen Viskosität eine sehr geringe thermische Leitfähigkeit. Durch Dissipation im Fluid bildet sich so ein Temperaturfeld aus. Mit dem verwendeten Doppelschneckenextruder wird das Temperatur‐ und Druckfeld sowie integrale Größen wie Durchsatz und Leistung untersucht. Die Ergebnisse werden mit numerischen Simulationen verglichen. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bistable Resonance In Gravity‐driven Film Flows
Authors: Heining C. , Wierschem A. , Aksel N.
Published: January 2007

We study the flow of a viscous liquid down an inclined plane with a sinusoidal bottom profile. Applying the integral boundarylayer method leads to a nonlinear ordinary differential equation for the film thickness. Linear resonance between the free surface and the bottom contour is observed via a regular perturbation approach. Considering nonlinear contributions, the resonance curve shows a foldover effect which is typical for nonlinear oscillators. In order to understand the origin of this bistable behaviour we derive a simple model equation and show an analogy to the Duffing oscillator. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pressure distributions in a channel with a backward facing step
Authors: Jonáš Pavel , Mazur Oton , Uruba Václav
Published: January 2007

Understanding of the process of a turbulent shear flow separation and reattachment is an important task of fluid dynamics. Channel flow with a step expansion on one wall is the simplest reattaching flow in view of the facts that the separation line is defined, the flow region geometry is easy to describe for the mathematical and physical modelling requirements, the experimental arrangement design is not difficult and it is repeatable in another laboratory exactly. These reasons were the motivation for the introductory experiments reported in [1] and for the continuation in the investigation of the assembly of new configurations using more sophisticated experimental methods. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Admixture stratification in the stagnation region of two streams
Authors: Lebedeva N. A. , Osiptsov A. N.
Published: January 2007

A self‐similar 2D steady‐state flow of two immisible viscous fluids with inertial particles is considered. It is assumed that two viscous streams, one of which contains the particles, collide forming a flat interface with a stagnation point. The general case is discussed, when the fluids have different viscosities and densities and the streams are directed at arbitrary angles. The far field corresponds to inviscid vortex flow near an “oblique” stagnation point. The limiting case of viscous dusty flow near a rigid plane is studied in detail within one‐way and two‐way coupling approximations. Thin zones of particle accumulation are detected. Threshold parameters corresponding to the change of flow regime are found. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shear Viscosity of the Gaussian Core Model Fluid
Authors: Mausbach P. , May H.‐O.
Published: January 2007

By means of molecular dynamics simulations we investigated the shear viscosity of the Gaussian Core Model fluid. We observed anomalous viscous behaviour for dimensionless densities greater than 0.3 and dimensionless temperatures below 0.04. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Wavelets on Regular Surfaces Generated by Stokes Potentials
Authors: Mayer Carsten
Published: January 2007

By means of the limit and jump relations of potential theory with respect to the Stokes equations the framework of a tensorial wavelet approach on a regular (Lyapunov‐) surface is established. The setup of a multiresolution analysis is defined by interpreting the kernel functions of the limit and jump integral operators as scaling functions on the regular surfaces. The distance of the parallel surface to the surface under consideration thereby represents the scale level in the scaling function. Tensorial scaling functions and wavelets show space localizing properties. Thus, they can be used to represent vector fields locally on a regular surface. Furthermore, these functions can be used as ansatz functions for the discretization of Fredholm integral equations of the second kind which result from the Stokes boundary‐value problems with respect to a regular surface. By this, scaling functions and wavelets enable us to give a multiscale representation of the solution of the Stokes problem. This representation will be demonstrated in a concrete example. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Viscosity Characterisation for Rubber Blends from Die Swell Data by means of a Genetic Algorithm
Authors: Müllner Herbert W. , Eberhardsteiner Josef , Hofstetter Karin
Published: January 2007

The goal of this contribution is the identification of the interaction of the typical swelling behaviour of viscoelastic fluids and the viscosity of the investigated rubber blends in the context of an extrusion process. By adaptation the fitness equation of the used genetic algorithm it is possible to study the influence of the die swell on viscous properties. With this knowledge a more realistic simulation of the die swell phenomenon and its influence on the resulting profile geometry is possible. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical simulation of the filling behavior of a Non‐Newtonian Fluid
Authors: Rudert Alexander , Schwarze Rüdiger
Published: January 2007

A numerical model for free surface flows of non‐newtonian liquids which are injected into a cavity is presented. These flows are regarded as a basic model of injection molding. Model experiments of the injection process are performed with a water‐based gel.

The flow equations are integrated according to the finite‐volume‐method. The volume of fluid method (VoF) is employed in order to describe the free surface flow of two incompressible phases, the phase interface is resolved by the method of geometric reconstruction. The Herschel‐Bulkley model is used in order to describe shear‐thinning behavior of the molding material and the effects of a yielding point.

Different patterns of the filling flow depending on the injection parameters are evident in the experiment and the simulation. They are characterized and arranged with respect to the similarity parameters of the flow. Again, the results of the simulation are found to agree well with the experimental observations. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mixed Convection Flow Past a Horizontal Plate: The Trailing Edge
Authors: Savić Lubomir , Steinrück Herbert
Published: January 2007

The mixed convection flow past a horizontal plate which is aligned under a small angle of attack to a uniform free stream will be considered in the limit of large Reynolds number and small Richardson number close to the trailing edge. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flow instabilities in thermocapillary liquid pools
Authors: Schoisswohl U. , Kuhlmann H.
Published: January 2007

The instability of steady axisymmetric thermocapillary flow in liquid pools heated from above is investigated numerically. The conditions for the onset of three‐dimensional motion depend on the thermal conditions as well as the geometrical constraints. The critical Reynolds number is calculated as a function of the Prandtl number for a cylindrical pool of unit aspect ratio. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mixed Convection Flow Past a Horizontal Plate: The Global Flow
Authors: Steinrück Herbert , Savić Ljubomir
Published: January 2007

The mixed convection flow past a horizontal plate which is aligned under a small angle of attack to a uniform free stream will be considered in the limit of large Reynolds number and small Richardson number. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of amyl acetate sorption on mechanical and thermal properties of polypropylene packaging
Authors: Safa Laurent , Abbès Boussad , Zaki Oussama
Published: January 2007

Sorption kinetics of amyl acetate in polypropylene is studied at 23, 40 and 55°C. Diffusion (D) and partition (Kp) coefficients were determined by fitting the sorption curves with a theoretical curve calculated from Fick's diffusion equation. The role of temperature and concentration of amyl acetate was investigated. The results show that D is not affected and Kp decreases with increasing concentration of amyl acetate in the solution. The sorption rate or total amount absorbed increased considerably with temperature. Concentration profiles were calculated by using a numerical algorithm based on a finite element method. The effect of amyl acetate concentration on the mechanical and thermal properties of the polymer was investigated. Copyright © 2007 John Wiley & Sons, Ltd.
Which constructs can predict emotional exhaustion in a working population? A study into its determinants
Authors: Michielsen Helen J. , Croon Marcel A. , Willemsen Tineke M. , De Vries Jolanda , Van Heck Guus L.
Published: January 2007

The main objective of this study was to examine the psychosocial stress model developed by Taylor and Aspinwall with emotional exhaustion as the outcome variable. Respondents, 409 men and 346 women, who had a paid job for at least 20 hours per week, completed questionnaires concerning demographic variables, personality, temperament, work pressure, workload, perceived social support, appraisal, coping, and emotional exhaustion. Structural equation analyses provided only partial support for the validity of the model. First, on theoretical and statistical grounds, one more path linking external resources to social support was added. Second, contrary to expectations, coping styles did not predict emotional exhaustion. To conclude, when coping is measured retrospectively, it does not add to our understanding of emotional exhaustion. It is suggested that future studies should be longitudinal and include objective measures of stressors and psychosocial health outcomes in addition to self‐reports. Copyright © 2007 John Wiley & Sons, Ltd.
Performance may predict natural killer cell activity after an acute time‐limited stressor
Authors: Lamkin Donald M. , Bloom Christopher M. , Michaels Zachary J. , Hunter Evelyn , Aguilar Miriam , Venard Jacob , Barnett Jeanne K.
Published: January 2007

Much attention has been given to natural killer cell activity (NKCA) in acute stressor research. While many studies show that acute stressors increase NKCA, fewer studies have investigated the variability in NKCA within an experimental group that is associated with performance. In his ‘Toughness’ theory of arousal, Richard Dienstbier suggests that behavioural performance during an acute stressor task could account for a variability in NKCA. We were not aware of any human studies that had investigated this possibility. Thus, in the present study we tested Dienstbier's proposal in a group of male and female human participants (n = 25) who completed a 4‐min serial subtraction mental arithmetic task. Blood samples were taken before and after the task. Controlling for baseline NKCA, performance score significantly predicted post‐task NKCA, β = 0.455, p = 0.01, and accounted for 25 per cent of the variance. Coincidence test showed no significant difference between men and women in predicting post‐task NKCA on performance score. Thus, in addition to evidence in the animal literature, the present study provides evidence that performance on an acute stressor is associated with enhanced NKCA in humans. Copyright © 2007 John Wiley & Sons, Ltd.
Egr‐1, a new downstream molecule of Epstein‐Barr virus latent membrane protein 1
Authors: Kim Joo Hyun , Kim Won Seog , Kang Jung Hun , Lim Ho-Yeong , Ko Young-Hyeh , Park Chaehwa
Published: January 2007

To investigate the effect of Epstein‐Barr virus (EBV) latent membrane protein 1 (LMP1) on human cancer cells, we sought to identify and analyze potential target genes that were differentially expressed in the presence and absence of LMP1. Our cDNA microarray analysis revealed that expression of early growth response gene‐1 (Egr‐1) was increased by LMP1 expression in MCF7 and Jurkat cells. An NFκB inhibitor (SN50) antagonized LMP1‐induced enhancement of Egr‐1 expression, indicating that LMP1 induced Egr‐1 via NFκB. Furthermore, three lines of evidence indicated that Egr‐1 was required for LMP1‐induced cancer cell survival. First, Egr‐1 expression enhanced the survival of doxorubicin‐treated MCF7 cells. Second, inhibition of Egr‐1 expression by siRNA (siEgr‐1) effectively suppressed LMP‐1‐induced survival of MCF7 cells. Third, Egr‐1 knockdown decreased LMP1‐induced expression of Bfl‐1. Similar relationships among EBV infection, Egr‐1 and drug resistance were also observed in tissues of peripheral T‐cell lymphoma‐unspecified (PTCL‐u) patients.
Diacylglycerol kinase γ interacts with and activates β2‐chimaerin, a Rac‐specific GAP, in response to epidermal growth factor
Authors: Yasuda Satoshi , Kai Masahiro , Imai Shin-ichi , Kanoh Hideo , Sakane Fumio
Published: January 2007

Diacylglycerol kinase (DGK)γ was shown to act as an upstream suppressor of Rac1. Here we report that, in COS7 cells stimulated with epidermal growth factor (EGF), DGKγ specifically interacts and co‐localizes at the plasma membrane with β2‐chimaerin, a GTPase‐activating protein (GAP) for Rac. Moreover, DGKγ enhanced EGF‐dependent translocation of β2‐chimaerin to the plasma membrane. Interestingly, DGKγ markedly augmented EGF‐dependent GAP activity of β2‐chimaerin through its catalytic action. These results indicate that DGKγ is a novel regulator of β2‐chimaerin, and thus suggest that β2‐chimaerin is an effector molecule, linking DGKγ functionally with Rac1.
Mutational analysis revealed that conservation of hepatitis B virus reverse transcriptase residue 306 (rtP306) is crucial for encapsidation of pregenomic RNA
Authors: Wang Yong-Xiang , Xu Xiang , Luo Cheng , Ma Zhang-Mei , Jiang Hua-Liang , Ding Jian-Ping , Wen Yu-Mei
Published: January 2007

Hepatitis B virus (HBV) is a DNA virus which replicates via reverse transcription. The structure and function of the reverse transcriptase play important roles in HBV replication. We have previously reported that when proline at residue 306 in HBV reverse transcriptase was substituted by other amino acids, most of the mutants showed decreased replicative competency. To explore the mechanisms for this decrease in replicative competency, constructs with substituted amino acid residues at rtP306 were used to transfect Huh‐7 cells, and replication competencies, transcription levels and encapsidation efficiencies of the mutants and the parental viral strain were compared. Decreased replication competency was found with many of the mutants and confirmed by trans‐complementation between each mutant and a replication‐defective replicon. No change in transcriptional level was detected between all mutated constructs. The encapsidation competencies of these constructs were studied by assaying pregenomic RNAs in intracytoplamic core particles from transfected cells, which were normalized for the amount of HBV core protein by Western blotting using anti‐core antibodies. Impaired encapsidation was found in several mutants substituted at residue 306, thereby demonstrating for the first time that conservation of proline at this residue is crucial for efficient encapsidation of pregenomic RNA.
Delinquent drug takers: a follow up
Authors: Ellis Mary J.L.
Published: January 2007

The two sub samples of drug taking delinquents described in an earlier article were followed up 5 and 3 years after their discharge. This paper describes the follow‐up findings and relates these to the original drug abusing status and social profile of the men. Some positive predictive findings were made. The study is illustrated with brief case histories.
The disturbed adolescent and his family: problems of individuation
Authors: Berkowitz David A.
Published: January 2007

The intrapsychic developmental task of adolescent individuation is examined from the standpoint of an adolescent‐family system in interaction. Interferences to this developmental task and resistances to treatment arising from both the adolescent and the family are discussed. The author focuses on counter‐separation attitudes and behaviors on the part of the family and the motivation for these attitudes and behaviors. Some therapeutic implications are discussed.
An interactional view of problem maintenance: the Davies family
Authors: Cade Brian W.
Published: January 2007

This paper, illustrated by a particular case example, will demonstrate how symptomatic behaviour can be seen as just one imput in a repetitive sequence of behaviours through which a system regulates itself and adjusts to pressures from internal or external sources to change. The paper will seek also to demonstrate how the imputs of the helping professions can inadvertently help maintain rather than change such a system.
The supervised adolescent: sharing the task with parents
Authors: Wilson Paddy , Brown Joan
Published: January 2007

In England and Wales the main non‐custodial sentences available today to the Juvenile Court dealing with young offenders under the age of 17 are Care Orders, Supervision Orders and Attendance Centre Orders. A Supervision Order is more likely to be chosen by the Court if the circumstances of the offence can be reasonably evidenced as a reaction to internal or external factors which have distorted the normal development of the young offender. However, the value of Supervision Orders has come under increasing criticism. It is often seen as a “soft option”, and harsher sentences are therefore being advocated by some sections of society. This paper focuses on an approach devised to make Supervision Orders more effective. Evidence from meetings with parents shows that Supervision which is not shared as a co‐operative task with parents is reduced to a perfunctory gesture.
Dynamic aspects of professional collaboration in child guidance referral
Authors: Reder Peter , Kraemer Sebastian
Published: January 2007

This paper focuses on the dynamic aspects of inter‐professional collaboration in cases referred to a Child Guidance Clinic when at least one other professional agency is already involved and when the referral has not come directly from the family. In some such cases the actual process of referral may replicate in the professional network many of the problems of the family whose child is referred. This is termed a system counter‐transference. Clinical abstracts are presented to illustrate the psychological and professional issues about authority and responsibility that can arise during referral.
Creative writing and ego development
Authors: Viorst Judith
Published: January 2007

The concept and format of a creative writing course for hospitalized adolescents is presented here and discussed in terms of the conflict‐free ego and identification with the functions, techniques and sublimatory aims of the “professional writer.” It is my conclusion that a writing course taught “as art and accomplishment” can mobilize and expand ego strength.
Treatment of transsexualism in adolescence
Authors: Kronberg J. , Tyano S. , Apter A. , Wijsenbeek H.
Published: January 2007

The purpose of this paper is to discuss transsexualism and to present our experience in treating an adolescent girl who suffered from this disorder. Our experience over the last few years in treating cases with gender identity problems and our study of the literature has led us to believe that it is important to recognize the symptomatology as early as possible during adolescence in order to increase the chances for successful therapy.
Geochemical constraints on the petrogenesis of the Proterozoic granitoid gneisses from the eastern segment of the Central Tianshan Tectonic Zone, northwestern China
Authors: LI QIUGEN , LIU SHUWEN , WANG ZONGQI , YAN QUANREN , GUO ZHAOJIE , ZHANG ZHICHENG , ZHENG HAIFEI , JIANG CHUNFA , WANG TAO , CHU ZHUYIN
Published: January 2007

The Tianshan orogen is divided into the Northern, Central and Southern Tianshan tectonic zones by the northern and southern sutures on both sides of the Central Tianshan Tectonic Zone. The eastern segment of the Central Tianshan Tectonic Zone is characterized by the presence of numerous Precambrian metamorphic blocks and is unconformably overlain by Ordovician–Silurian and late Palaeozoic strata. The Precambrian Kumishi and Pargantag metamorphic blocks are the largest older blocks in the eastern segment of the Central Tianshan Tectonic Zone, consisting mainly of metamorphic granitoids and sedimentary rocks in greenschist to amphibolite facies. There are two major lithological assemblages of the metamorphic granitoids: (1) quartz dioritic gneisses, and (2) granodioritic–monzogranitic gneisses with a minor amount of tonalitic and syenogranitic gneisses in both the Kumishi and Pargantag blocks. The quartz dioritic gneisses are characterized by low Sr/Ce (<5.3) and Sr/Y (<28), relatively high Mg no. (51.0–57.0), K2O (2.65–4.04 wt %) contents and εNd(t) values (−2.37–5.84), and negative Nb and Zr–Hf anomalies, as well as relatively flat chondrite-normalized REE patterns with slightly negative Eu anomalies, suggesting that the quartz dioritic gneisses were derived from partial melting of a depleted mantle source enriched by fluids and sedimentary melts from the subducted slab. However, most of granitic gneiss samples display high K2O contents, low Al2O3/(FeO* + MgO + TiO2) values, and relatively flat chondrite-normalized REE patterns with intensively negative Eu anomalies. Integrated low εNd(t) values and older TDM model ages suggest that crustal materials played a significant role in the petrogenesis of these granitoid gneisses and that they were mainly derived from the partial melting of calc-alkaline mafic to intermediate rocks in the crust. Also, variations in geochemical features between the Kumishi–Gangou and Pargantag regions, such as Zr and Hf, may reflect geographic variability in the development of coeval granitic magmas. Tectonic discrimination for granitoid, using trace elements, together with Nd isotopic data, demonstrates that these granitoid gneisses in the eastern segment of the Central Tianshan Tectonic Zone formed in a continental margin arc during late Mesoproterozoic times.
Productivity and optimum plant density of pigeonpea in different environments in Tanzania
Authors: MLIGO J. K. , CRAUFURD P. Q.
Published: January 2007

The objective of the present study was to determine the optimum plant density of four pigeonpea genotypes, representing early, medium and late maturing types, grown in five contrasting environments in Tanzania. ICPL 86005 (early), Kat 50/3 and QP 37 (medium) and Local (late) were grown at four plant densities (40 000–320 000 plants/ha) in irrigated and rainfed conditions at Ilonga and under rainfed conditions at Kibaha, Selian and Ismani. At maturity, total above-ground biomass and seed yield (SY) were measured. The highest yields were obtained in the irrigated experiment at Ilonga, where the medium/late genotypes produced 25 t biomass/ha and 5·6 t seed/ha. The lowest SY were at Kibaha, 0·58 to 1·76 t/ha, where a severe drought occurred. In nearly all cases the response to density was linear or asymptotic. The response of ICPL 86005 was significantly different from the other three genotypes. The optimum density for SY varied from 37 000 to 227 000 plants/ha in ICPL 86005, compared with 3000 to 101 000 plants/ha in the medium/late genotypes. The highest optimum density was at Selian and Ismani and the lowest at Ilonga and Kibaha, where drought occurred. Optimum densities therefore varied greatly with genotype (duration) and environment, and this variation needs to be considered when planning trials.
Immobilization antibodies of tiger puffer Takifugu rubripes induced by i.p. injection against monogenean Heterobothrium okamotoi oncomiracidia do not prevent the infection
Authors: UMEDA N. , HATANAKA A. , HIRAZAWA N.
Published: January 2007

We examined whether infection by the monogenean Heterobothrium okamotoi induces production of specific antibodies against oncomiracidia and their cilia, larvae on the gills, and adults on the branchial cavity wall of tiger puffer Takifugu rubripes. We also investigated whether specific antibody production participates in acquired protection against H. okamotoi. Sera from persistently infected fish immobilized H. okamotoi oncomiracidia 89 days after exposure and antibody levels (measured by enzyme-linked immunosorbent assays) in the sera against oncomiracidia and their cilia increased compared with sera from control (naïve) fish. Antibody levels in these sera against the larvae and adult stages did not increase. The number of H. okamotoi on persistently infected fish was significantly lower than for control fish (P<0·05) when persistently infected fish and control fish were exposed to oncomiracidia in the same tank. Thus tiger puffer produced specific antibodies against oncomiracidia and their cilia, and acquired partial protection against H. okamotoi. Intraperitoneal injection of proteins of sonicated oncomiracidia or their cilia with an adjuvant also produced oncomiracidium agglutination antibodies in sera from tiger puffer; the antibody levels in these sera against oncomiracidia and their cilia increased compared with sera from control fish (injection of BSA with an adjuvant) at 14, 44, and 75 days after the booster immunization. However, in a parasite challenge at 54–58 days after the booster immunization, the infection levels of fish immunized with parasites of sonicated oncomiracidia or their cilia were the same as the control fish. Western blot showed that sera from persistently infected fish and fish immunized with sonicated oncomiracidia or their cilia recognized similar antigenic bands, suggesting that tiger puffer tends to react against these antigens compared with other antigens. These results indicated that specific antibodies against these cilia and oncomiracidia induced by i.p. injection do not prevent H. okamotoi infection.
Observation of repeated intense near‐Earth reconnection on closed field lines with Cluster, Double Star, and other spacecraft
Authors: Sergeev V. , Semenov V. , Kubyshkina M. , Ivanova V. , Baumjohann W. , Nakamura R. , Penz T. , Runov A. , Zhang T. L. , Glassmeier K.‐H. , Angelopoulos V. , Frey H. , Sauvaud J.‐A. , Daly P. , Cao J. B. , Singer H. , Lucek E.
Published: January 2007

We report strong repeated magnetic reconnection pulses that occurred deep inside closed plasma sheet flux tubes at r ≤ 14Re. They have been observed with a fortuitous spacecraft constellation during three consecutive turbulent magnetic dipolarizations, accompanied by localized auroral brightenings near the equatorward edge of a wide auroral oval. The reconnection separatrix was mapped to ∼64° CGLat in the ionosphere, where a very energetic and narrow energy‐dispersed ion injection with unusually steep dispersion slope was observed. Reconstruction of the reconnection rate from magnetic waveforms at Cluster provided a reconnection pulse duration (∼1 min) and peak strength (ER ∼ 8 mV/m) consistent with direct observations in the reconnection outflow region. The magnetic activity was rather weak, although the concurrent solar wind flow pressure was above the norm. We suggest that near‐Earth reconnection events may be a phenomenon more frequent than generally thought. We also confirm that reconnection and the growth of strong turbulence in the near tail are strongly coupled together in near‐Earth reconnection events.
Magnetic flux transport in the Dungey cycle: A survey of dayside and nightside reconnection rates
Authors: Milan S. E. , Provan G. , Hubert B.
Published: January 2007

Changes in the open flux content of the ionospheric polar cap, estimated from auroral, radar, and low‐Earth orbit particle measurements, are used to determine dayside and nightside reconnection rates during 73 hours of observation spread over nine intervals. We identify 25 episodes of nightside reconnection and examine statistically the rates and durations of reconnection, as well as possible triggers for the onset of reconnection, such as changes in solar wind ram pressure or orientation of the interplanetary magnetic field. Approximately half of the events can possibly be identified with a trigger, the other half appearing spontaneous. On average 0.3 GWb of open flux are closed in each event, with average durations and reconnection rates being 70 min and 85 kV. We find no evidence for a low background rate of nightside reconnection between these events and conclude that substorms and other large reconnection bursts provide the major or only source of flux closure on the nightside.
Polar wind outflow model: Saturn results
Authors: Glocer A. , Gombosi T. I. , Toth G. , Hansen K. C. , Ridley A. J. , Nagy A.
Published: January 2007

The Saturnian system's configuration and dynamics are to a large extent controlled by the planet's rapid rotation and the plasma in the magnetosphere. Therefore characterizing the relative importance of the various plasma sources is crucial to understanding Saturn's magnetosphere. Most research in this area focuses on the addition of mass from the icy satellites, the rings, and Titan, while comparatively little attention has been paid to the ionospheric source. We investigate the ionospheric source at high latitude using multifluid numerical simulations of Saturn's polar wind and find that the magnitude of the particle source rate out of the polar cap is between 2.1 × 1026 and 7.5 × 1027 s−1. Our multifluid simulations are carried out using the Polar Wind Outflow Model (PWOM). This new model is capable of calculating the polar wind at Earth and Saturn by solving the gyrotropic transport equations. The polar wind at Saturn is modeled from below the peak ionospheric density to an altitude of one Saturn radius, yielding fluxes for H3+, H+, and electrons. Because the neutral temperature is ill constrained, we calculate source rates for various Saturnian atmospheric profiles corresponding to neutral temperatures of 420, 600, 800, 1000, 1500 K. We compare the results with those calculated from other models and measurements where appropriate.
Influences of biomass heat and biochemical energy storages on the land surface fluxes and radiative temperature
Authors: Gu Lianhong , Meyers Tilden , Pallardy Stephen G. , Hanson Paul J. , Yang Bai , Heuer Mark , Hosman Kevin P. , Liu Qing , Riggs Jeffery S. , Sluss Dan , Wullschleger Stan D.
Published: January 2007

The interest of this study was to develop an initial assessment on the potential importance of biomass heat and biochemical energy storages for land‐atmosphere interactions, an issue that has been largely neglected so far. We conducted flux tower observations and model simulations at a temperate deciduous forest site in central Missouri in the summer of 2004. The model used was the comprehensive terrestrial ecosystem Fluxes and Pools Integrated Simulator (FAPIS). We first examined FAPIS performance by testing its predictions with and without the representation of biomass energy storages against measurements of surface energy and CO2 fluxes. We then evaluated the magnitudes and temporal patterns of the biomass energy storages calculated by FAPIS. Finally, the effects of biomass energy storages on land‐atmosphere exchanges of sensible and latent heat fluxes and variations of land surface radiative temperature were investigated by contrasting FAPIS simulations with and without these storage terms. We found that with the representation of the two biomass energy storage terms, FAPIS predictions agreed with flux tower measurements fairly well; without the representation, however, FAPIS performance deteriorated for all predicted surface energy flux terms although the effect on the predicted CO2 flux was minimal. In addition, we found that the biomass heat storage and biochemical energy storage had clear diurnal patterns with typical ranges from −50 to 50 and −3 to 20 W m−2, respectively; these typical ranges were exceeded substantially when there were sudden changes in atmospheric conditions. Furthermore, FAPIS simulations without the energy storages produced larger sensible and latent heat fluxes during the day but smaller fluxes (more negative values) at night as compared with simulations with the energy storages. Similarly, without‐storage simulations had higher surface radiative temperature during the day but lower radiative temperature at night, indicating that the biomass energy storages act to dampen the diurnal temperature range. From these simulation results, we concluded that biomass heat and biochemical energy storages are an integral and substantial part of the surface energy budget and play a role in modulating land surface temperatures and must be considered in studies of land‐atmosphere interactions and climate modeling.
Comparative genomics and disorder prediction identify biologically relevant SH3 protein interactions
Authors: Beltrao Pedro , Serrano Luis
Published: January 2007

Protein interaction networks are an important part of the post-genomic effort to integrate a part-list view of the cell into system-level understanding. Using a set of 11 yeast genomes we show that combining comparative genomics and secondary structure information greatly increases consensus-based prediction of SH3 targets. Benchmarking of our method against positive and negative standards gave 83% accuracy with 26% coverage. The concept of an optimal divergence time for effective comparative genomics studies was analyzed, demonstrating that genomes of species that diverged very recently from Saccharomyces cerevisiae (S. mikatae, S. bayanus, and S. paradoxus), or a long time ago (Neurospora crassa and Schizosaccharomyces pombe), contain less information for accurate prediction of SH3 targets than species within the optimal divergence time proposed. We also show here that intrinsically disordered SH3 domain targets are more probable sites of interaction than equivalent sites within ordered regions. Our findings highlight several novel S. cerevisiae SH3 protein interactions, the value of selection of optimal divergence times in comparative genomics studies, and the importance of intrinsic disorder for protein interactions. Based on our results we propose novel roles for the S. cerevisiae proteins Abp1p in endocytosis and Hse1p in endosome protein sorting.
Why is the microtubule lattice helical?
Authors: Hunyadi Viktória , Chrétien Denis , Flyvbjerg Henrik , Jánosi Imre M.
Published: January 2007

Microtubules polymerize from identical tubulin heterodimers, which form a helical lattice pattern that is the microtubule. This pattern always has left‐handed chirality, but it is not known why. But as tubulin, similar to other proteins, evolved for a purpose, the question of the title of this artcile appears to be meaningful. In a computer simulation that explores the ‘counterfactual biology’ of microtubules without helicity, we demonstrate that these have the same mechanical properties as Nature's microtubules with helicity. Thus only a dynamical reason for helicity is left as potential explanation. We find that helicity solves ‘the problem of the blind mason’, i.e. how to correctly build a structure, guided only by the shape of the bricks. This answer in turn raises some new questions for researchers to address.
Current knowledge of the large RhoGAP family of proteins
Authors: Tcherkezian Joseph , Lamarche‐Vane Nathalie
Published: January 2007

The Rho GTPases are implicated in almost every fundamental cellular process. They act as molecular switches that cycle between an active GTP‐bound and an inactive GDP‐bound state. Their slow intrinsic GTPase activity is greatly enhanced by RhoGAPs (Rho GTPase‐activating proteins), thus causing their inactivation. To date, more than 70 RhoGAPs have been identified in eukaryotes, ranging from yeast to human, and based on sequence homology of their RhoGAP domain, we have grouped them into subfamilies. In the present Review, we discuss their regulation, biological functions and implication in human diseases.
Improved usability of the minimal model of insulin sensitivity based on an automated approach and genetic algorithms for parameter estimation
Authors: Morbiducci Umberto , Di Benedetto Giacomo , Kautzky-Willer Alexandra , Pacini Giovanni , Tura Andrea
Published: January 2007

Minimal model analysis of glucose and insulin data from an IVGTT (intravenous glucose tolerance test) is widely used to estimate insulin sensitivity; however, the use of the model often requires intervention by a trained operator and some problems can occur in the estimation of model parameters. In the present study, a new method for minimal model analysis, termed GAMMOD, was developed based on genetic algorithms for the estimation of model parameters. Such an algorithm does not require the fixing of initial values for the parameters (that may lead to unreliable estimates). Our method also implements an automated weighting scheme not requiring manual intervention of the operator, thus improving the usability of the model. We studied a group of 170 women with a history of previous gestational diabetes. Results obtained by GAMMOD were compared with those obtained by MINMOD (a traditional gradient-based algorithm for minimal model analysis). Insulin sensitivity by GAMMOD was (3.86±0.19) compared with (4.33±0.20)×10−4 μ-units·ml−1·min−1 by MINMOD; glucose effectiveness was 0.0236±0.0005 compared with 0.0229±0.0005 min−1 respectively. The difference in the estimation by the two methods was within the precision expected for such metabolic parameters and is probably of no clinical relevance. Moreover, both the coefficient of variation of the estimated parameters and the error of fit were generally lower in GAMMOD, despite the fact that it does not require manual intervention. In conclusion, the GAMMOD approach for parameter estimation in the minimal model provides a reliable estimation of the model parameters and improves the usability of the model, thus facilitating its further use and application in a clinical context.
A functional study of plasma-membrane calcium-pump isoform 2 mutants causing digenic deafness
Authors: Ficarella R. , Di Leva F. , Bortolozzi M. , Ortolano S. , Donaudy F. , Petrillo M. , Melchionda S. , Lelli A. , Domi T. , Fedrizzi L. , Lim D. , Shull G. E. , Gasparini P. , Brini M. , Mammano F. , Carafoli E.
Published: January 2007

Ca
2+
enters the stereocilia of hair cells through mechanoelectrical transduction channels opened by the deflection of the hair bundle and is exported back to endolymph by an unusual splicing isoform (
w
/
a
) of plasma-membrane calcium-pump isoform 2 (PMCA2). Ablation or missense mutations of the pump cause deafness, as described for the G283S mutation in the deafwaddler (
dfw
) mouse. A deafness-inducing missense mutation of PMCA2 (G293S) has been identified in a human family. The family also was screened for mutations in cadherin 23, which accentuated hearing loss in a previously described human family with a PMCA2 mutation. A T1999S substitution was detected in the cadherin 23 gene of the healthy father and affected son but not in that of the unaffected mother, who presented instead the PMCA2 mutation. The
w
/
a
isoform was overexpressed in CHO cells. At variance with the other PMCA2 isoforms, it became activated only marginally when exposed to a Ca
2+
pulse. The G293S and G283S mutations delayed the dissipation of Ca
2+
transients induced in CHO cells by InsP
3
. In organotypic cultures, Ca
2+
imaging of vestibular hair cells showed that the dissipation of stereociliary Ca
2+
transients induced by Ca
2+
uncaging was compromised in the
dfw
and PMCA2 knockout mice, as was the sensitivity of the mechanoelectrical transduction channels to hair bundle displacement in cochlear hair cells.
Collective Modes and Ground State Energy of the Semi-infinite Electron Gas
Authors: E Wikborg  , J E Inglesfield
Published: January 2007

The RPA linear response theory as applied to the semi-infinite electron gas, in particular the infinite barrier model, is discussed in terms of the normal mode charge density fluctuations of the system. The normal modes separate into a discrete, surface mode with an electric field extending outside the solid and a continuum of bulk modes with no such fields. The surface mode, which corresponds to the undamped surface plasmon in the longwavelength limit, is examined at wave vectors up to the plasmon cut-off where it merges with the bulk modes. The bulk modes are also affected by the surface and we have calculated their phase shifts as a function ofx, the wave vector perpendicular to the surface. In terms of these phase shifts we then discuss the change in the number of bulk modes when a surface is created; about 1/4 of a bulk mode is removed over an interval close tox=0 in addition to another 1/4 removed discretely atx=0. The surface exchange-correlation energy can be split into the change in the zero-point energy of the plasmons and the contribution from the screened electron-hole pair excitations, and we discuss the contribution in terms of zero-point energy of the surface plasmon and the change in the number of bulk modes.
Influence of Random Inhomogeneities on Parametric Interactions
Authors: A Bondeson
Published: January 2007

An investigation is made of parametric wave interactions in weakly turbulent media. Effective growth-rates and thresholds for mean amplitude and mean power growth are calculated allowing for arbitrary dampings of the excited modes and a nonzero average mismatch. Convective amplification in a linear mismatch profile is discussed.