bluuebunny/crossref_metadata_2025 huggingface dataset:
Heterotetramers Formed by an S‐Layer–Streptavidin Fusion Protein and Core‐Streptavidin as a Nanoarrayed Template for Biochip Development
Authors: Huber Carina , Liu Jing , Egelseer Eva M. , Moll Dieter , Knoll Wolfgang , Sleytr Uwe B. , Sára Margit
Published: October 2005

Based on the S‐layer protein SbpA of Bacillus sphaericus CCM 2177, an S‐layer–streptavidin fusion protein was constructed. After heterologous expression, isolation of the fusion protein, and refolding, functional heterotetramers were obtained that had retained the ability to recrystallize into the square‐lattice structure on plain gold chips and on gold chips precoated with secondary cell wall polymer (SCWP), which is the natural anchoring molecule for the S‐layer protein in the bacterial cell wall. Monolayers generated by recrystallization of heterotetramers on plain gold chips or on gold chips precoated with thiolated SCWP were exploited for the binding of biotinylated oligonucleotides (30‐mers). Hybridization experiments with complementary fluorescently labeled oligonucleotides carrying one mismatch or no mismatch (both 15‐mers) were performed and evaluated with surface‐plasmon‐field‐enhanced fluorescence spectroscopy. For surfaces generated by the recrystallization of heterotetramers on SCWP‐coated gold chips, a detection limit of 1.57 pM could be determined, whereas for surfaces obtained by direct recrystallization of heterotetramers on plain gold chips, a detection limit of 8.2 pM was found. Measuring the association and dissociation processes of oligonucleotides carrying no mismatch led to a dissociation constant of KD=6.3×10−10 m, whereas for oligonucleotides carrying one mismatch a dissociation constant of KD=7.9×10 −9 m was determined. This finding was confirmed by measuring the whole Langmuir isotherm, which resulted in a dissociation constant of KD=2.6×10−8 m.
Microwave‐Assisted Synthesis and Characterization of Succinate Derivatives of Cassava (Manihot esculenta Crantz) Starch
Authors: Jyothi Alummoottil N. , Rajasekharan Kallikat N. , Moorthy Subramoney N. , Sreekumar Janardhanan
Published: October 2005

The use of microwave heating to prepare very rapidly cassava starch succinates with high viscosity is described. A response surface design was used for the experiment and different factors affecting the succinylation of cassava starch, including concentration of succinic anhydride, reaction time, temperature and moisture content of the medium were investigated. The degrees of substitution of the modified starches increased with an increase in reaction time and were in the range 0.007 – 0.051. The products exhibited higher viscosity, lower pasting temperature, enhanced water binding capacity and reduced swelling and paste clarity than unmodified cassava starch. The results of this study indicated that succinylation of starch can be achieved in shorter reaction times, which offers a benefit to laboratories and industries involved in developing newer and more versatile uses for cassava starch.
The Holy Spirit and time in contemporary Catholic and Protestant theology
Authors: Vondey Wolfgang
Published: October 2005

Contemporary Catholic and Protestant theology has transposed the scientific debate on time into an eschatological discussion about subjective time and objective time. This discussion can be made intelligible in the context of modern cosmology if we allow contemporary eschatology to be transformed by a pneumatological approach to time. In the self-giving of the Holy Spirit into time, the ‘wheel of history’ is identical with the eschatological arrow of history. This is exemplified in a theology of the cross which locates the eternal power of the cross not in the human act of anamnesis by recalling in the present Christ's sacrifice as an event of the past, but in the Holy Spirit who liberates Christ's historical sacrifice on the cross from its temporal coordinates and propels the redemptive act throughout time towards any person in history. A pneumatological approach to time suggests that eschatology is determined not only by the end and the consummation of the present in the future but also by the perpetuation of the present moment through the power of God unfolding in time in the operation of the Holy Spirit. If it can be shown that this is true not only for a theology of the cross, then it may be possible to say, in general, that the unique finality and collective character of God's work of salvation at any moment in history is made possible by the perpetuating work of the Holy Spirit as the eternal lord of time and history.
‘Naturally and by grace’: Maximus the Confessor on the operation of the will
Authors: McFarland Ian A.
Published: October 2005

Although Maximus' and Augustine's theologies of the will were shaped by very different polemical contexts, it is arguable that the two thinkers were interested in securing the same theological ground. In response to positions that treated the will as a reserve of human autonomy over against God, both thinkers sought to see the freedom of the will as a function of its integration into the natural order through grace. Maximus' concept of the natural will in particular functions as a means of challenging both divine determinism and human libertarianism as adequate accounts of the relationship between divine and human activity.
Development of a biped walking robot actuated by a closed-chain mechanism
Authors: Choi Hyeung-Sik , Park Yong-Heon
Published: October 2005

We developed a new type of a human-sized BWR (biped walking robot) driven by the closed-chain type of a joint actuator. Each leg of the BWR is composed of three pitch joints and one roll joint. In all, a 12 degree-of-freedom robot, including four arm joints, was developed. The BWR was designed to walk autonomously; it is actuated by small 90W DC motors/drivers and is has DC batteries and controllers. A new type of the joint actuator for the BWR is composed of the four-bar-link mechanism driven by a ball screw which has high strength and high gear ratio despite its light weight.

In this paper, analyses on the four-bar-link mechanism applied to the joint actuator and on the structure of the BWR are presented. Through walking experiments of the BWR, the superior trajectory-tracking ability of the proposed joint actuator is validated.
Control oriented dynamic formulation for robotic systems with program constraints
Authors: Jarzȩbowska Elżbieta
Published: October 2005

The paper presents a control oriented dynamic formulation for constrained robotic systems. We refer to this formulation as control oriented since it can be directly applied to design a model-based tracking control strategy. It enables one to obtain dynamic models for systems subjected to material constraints and non-material referred to as program constraints. The dynamic model for a constrained robot, where equations of program constraints specify tasks and motion requirements, is used as a program motion planner for a controller design. The formulation provides a theoretical framework, which is a basis for the study of robot performance of constrained tasks. Examples of developments of control oriented dynamic models are presented, and their applications for control are demonstrated and discussed.
Dynamic model and performances of 2-DOF manipulators
Authors: Di Gregorio Raffaele
Published: October 2005

Tools that make it possible to measure the performances of manipulators are essential in many technical applications, for instance, when the optimal path to accomplish a task has to be chosen, or when different manipulator architectures have to be compared. This paper proposes some indices that fully describe the passive dynamic performances of manipulators with two degrees of freedom (dof). The pro- posed indices make it possible to compare the passive dynamic performances of different manipulator architectures, which can perform the same tasks, and can be used to build diagrams which highlight the effects of variations in the manipulator geometry on the manipulator dynamics. These features make them easy to be used in a design context. Finally, some applications of the proposed indices will be presented and discussed.
Singular perturbation based neuro-H∞ control scheme for a manipulator with flexible links and joints
Authors: Subudhi B. , Morris A. S.
Published: October 2005

A novel composite control scheme for a manipulator with flexible links and joints is presented that uses the singular perturbation technique (SPT) to divide the manipulator dynamics into reduced order slow and fast subsystems. A neural network controller is then applied for the slow subsystem and a state-feedback H∞ controller for the fast subsystem. Results are presented that demonstrate improved performance over an alternative SPT-based controller that uses inverse dynamics and LQR controllers.
Experimental validation on the integrated design and control of a parallel robot
Authors: Li Qing
Published: October 2005

Due to the demands from the robotic industry, robot structures have evolved from serial to parallel. The control of parallel robots for high performance and high speed tasks has always been a challenge to control engineers. Following traditional control engineering approaches, it is possible to design advanced algorithms for parallel robot control. These approaches, however, may encounter problems such as heavy computational load and modeling errors, to name it a few. To avoid heavy computation, simplified dynamic models can be obtained by applying approximation techniques, nevertheless, performance accuracy will suffer due to modeling errors. This paper suggests applying an integrated design and control approach, i.e., the Design For Control (DFC) approach, to handle this problem. The underlying idea of the DFC approach can be illustrated as follows: Intuitively, a simple control algorithm can control a structure with a simple dynamic model quite well. Therefore, no matter how sophisticate a desired motion task is, if the mechanical structure is designed such that it results in a simple dynamic model, then, to design a controller for this system will not be a difficult issue. As such, complicated control design can be avoided, on-line computation load can be reduced and better control performance can be achieved. Through out the discussion in the paper, a 2 DOF parallel robot is redesigned based on the DFC concept in order to obtain a simpler dynamic model based on a mass-balancing method. Then a simple PD controller can drive the robot to achieve accurate point-to-point tracking tasks. Theoretical analysis has proven that the simple PD control can guarantee a stable system. Experimental results have successfully demonstrated the effectiveness of this integrated design and control approach.
Robotic yo-yo: modelling and control strategies
Authors: Žlajpah Leon
Published: October 2005

In the paper we address a problem of controlling an oscilmotion with a robot. As the object we have selected a yo-yo. First we have measured and analysed the motion of different yo-yos. We have developed a simplified model of a yo-yo which has one degree-of-freedom, and the behaviour at the end of the string is modelled as an impact. Next, we discuss the control strategy. Our results show, that for playing a yo-yo it is important to start the upward motion before the yo-yo reaches the bottom position and the acceleration has to be reversed after the bottom impact. We present two control strategies: one based on predefined hand motion pattern and and the other generating the hand motion on-line. Both allow playing the yo-yo at a selected top height. The theoretical results have been proven by experiments on a real robot system.
Quasi-human biped walking
Authors: Lim Hun-ok , Hyon Sang-ho , Setiawan Samuel A. , Takanishi Atsuo
Published: October 2005

Our goal is to develop biped humanoid robots capable of working stably in a human living and working space, with a focus on their physical construction and motion control. At the first stage, we have developed a human-like biped robot, WABIAN (WAseda BIped humANoid), which has a thirty-five mechanical degrees of freedom. Its height is 1.66 [m] and its weight 107.4 [kg]. In this paper, a moment compensation method is described for stability, which is based on the motion of its head, legs and arms. Also, a follow walking method is proposed which is based on a pattern switching technique. By a combination of both methods, the biped robot is able to perform dynamic stamping, walking forward and backward in a continuous time while someone is pushing or pulling its hand in such a way. Using WABIAN, human-fellow walking experiments are conducted, and the effectiveness of the methods are verified.
Modeling and simulation of swarms for collecting objects
Authors: Li Yangmin , Chen Xin
Published: October 2005

A mathematic model is established to describe a swarm with multi-behavior. Regarding a swarm designed for cooperative task, we propose a model which includes a macroscopic model and a individual-based model. The macroscopic framework model describes global dynamics of swarms, which is normally expressed by dynamical populations' densities with different behaviors, while the individual-based framework model describes a individual agent's trajectory. Based on these models, we prove that all objects can be collected to the “home” area under conditions of individual agents subject to sensor constraints.
Overall design of Ca.U.M.Ha. robotic hand for harvesting horticulture products
Authors: Figliolini Giorgio , Rea Pierluigi
Published: October 2005

The overall design of Ca.U.M.Ha. (Cassino-Underactuated-Multifinger-Hand) for harvesting horticulture products is presented. Ca.U.M.Ha. shows an anthropomorphic design incorporating four underactuated finger mechanisms and a simplified contrasting thumb, which are all joined to a rigid palm. The pneumatic cylinders of the articulated fingers are operated in parallel in order to give an additional auto-adaptability on the object to grasp. An application of Ca.U.M.Ha. for grasping different shapes of apples is presented.
Fault-tolerant crab gaits and turning gaits for a hexapod robot
Authors: Yang Jung-Min
Published: October 2005

This paper studies crab gaits and turning gaits of a hexapod robot with a locked joint failure. Due to the reduced workspace of a failed leg, fault-tolerant gaits have limitations in their mobility. Based on the principles of fault-tolerant gait planning, periodic crab gaits and turning gaits are proposed in which a hexapod robot carries out tripod walking after a locked joint failure, having a reasonable stride length and stability margin.
Please – from courtesy to appeal: the role of intonation in the expression of attitudinal meaning
Authors: WICHMANN ANNE
Published: October 2005

Intonation is known to convey many nuances of meaning, both emotional and attitudinal, but a way of explaining how these meanings arise has so far remained elusive. While some emotions may have direct correlates in a speaker's voice, such correlates are harder to find for attitudinal meanings.

The word please is typically a routine expression of courtesy, but data from the International Corpus of British English (ICE GB) reveals please to be a pragmatic marker with a wide range of expressive functions. This study, which uses a quantitative approach combined with qualitative analysis, has implications for the study of other pragmatic particles, and also provides the basis for the understanding of attitudinal intonation in a wider context.
Constraints on nonstandard -s in expletive there sentences: a generative–variationist perspective
Authors: RUPP LAURA
Published: October 2005

This article examines grammatical conditioning of the use of nonstandard -s in expletive there sentences. The discussion is based on data from a Midlands variety of English (UK). In negative constructions, speakers tend to allow for nonstandard -s with no and constituent not, but not to use it with n't or clausal not. Further, nonstandard -s is admitted in declarative existentials, but disfavoured in interrogatives. By comparison, occurrences of nonstandard -s in nonexistential structures did not seem to demonstrate these constraints. Investigating such constraints is instructive in several respects. First, they help to identify the nature of nonstandard -s. Second, they provide new evidence for the generative inquiry into issues relating to subject–verb agreement. Third, they delimit variable contexts for variationist analyses. In this way generative and variationist objectives meet. I will argue that researching syntactic variation necessitates combining generative and variationist methodology.
The written turn
Authors: BARON NAOMI
Published: October 2005

Vivian Cook, The English writing system. London: Arnold, 2004. Pp. vi + 229, ISBN 0 340 80864 0
Sparse Bayesian learning machine for real‐time management of reservoir releases
Authors: Khalil Abedalrazq , McKee Mac , Kemblowski Mariush , Asefa Tirusew
Published: October 2005

Water scarcity and uncertainties in forecasting future water availabilities present serious problems for basin‐scale water management. These problems create a need for intelligent prediction models that learn and adapt to their environment in order to provide water managers with decision‐relevant information related to the operation of river systems. This manuscript presents examples of state‐of‐the‐art techniques for forecasting that combine excellent generalization properties and sparse representation within a Bayesian paradigm. The techniques are demonstrated as decision tools to enhance real‐time water management. A relevance vector machine, which is a probabilistic model, has been used in an online fashion to provide confident forecasts given knowledge of some state and exogenous conditions. In practical applications, online algorithms should recognize changes in the input space and account for drift in system behavior. Support vectors machines lend themselves particularly well to the detection of drift and hence to the initiation of adaptation in response to a recognized shift in system structure. The resulting model will normally have a structure and parameterization that suits the information content of the available data. The utility and practicality of this proposed approach have been demonstrated with an application in a real case study involving real‐time operation of a reservoir in a river basin in southern Utah.
Simple wave and monoclinal wave models: River flow surge applications and implications
Authors: Ferrick M. G.
Published: October 2005

Unsteady flow surges in rivers can be idealized as a transition between lower steady flow downstream and higher steady flow upstream. Simple wave and monoclinal wave models are analytical solutions of the dynamic wave equations that can be used to model these surges. The simple wave model neglects bed slope and flow resistance, simulating surge propagation over relatively short distances. The monoclinal wave profile evolves progressively, and this model is generally applicable at larger distances. These models are easy to use and generally apply to different flow conditions. However, both models lack criteria to determine their suitability for specific applications. The objectives of this paper are to develop and to assess criteria to guide simple wave and monoclinal wave model applications and to use the models to gain insights into the inertia and slope–flow resistance contributions to momentum and the nonlinear effects of increasing surge amplitude. Simple wave model application criteria include a dimensionless time, the amplitude to initial amplitude ratio for a linear dynamic wave traveling downstream, a distance scale, and the ratio between the measured surge celerity and the c+ dynamic wave celerity of the high flow upstream. The length of the monoclinal‐diffusion wave profile gives the minimum distance needed to develop a steady monoclinal wave profile. Model capabilities to describe flow surges and the adequacy of the application criteria are evaluated with data from laboratory and field studies covering a wide range of conditions. Profile celerity and high flow velocity behind the surge are always greater for the simple wave than for the monoclinal wave because of the absence of slope and flow resistance effects. The differences between the models are enhanced as Froude number decreases and as surge amplitude increases.
Ensemble initial conditions through 4D‐Var assimilation
Authors: Goswami P. , Gouda K. C. , Talagrand O.
Published: October 2005

The methodology to generate members of an ensemble is an important issue in operational forecasting; currently a number of procedures are followed at different operational centres. In the present work we propose and evaluate a methodology where a dynamically consistent set of initial conditions is generated through 4D‐Var assimilation procedure. The perturbations are generated through 4D‐Var assimilation with different information (observation) content, either through a variation in the frequency of observations or a variation in the length of assimilation window. We adopt a representative non‐linear system, viz. the three‐variable Lorenz system and show that ensemble forecasts generated through 4D‐Var assimilation show less error than those generated from initial conditions (with similar amplitude of perturbation) adopted arbitrarily. Another advantage of the procedure is that it provides a (variable‐specific) estimate of the maximum allowed amplitude and spread of perturbations.
Spatio‐temporal change analysis to identify anomalous variation in the vegetated land surface: ENSO effects in tropical South America
Authors: Viña Andrés , Henebry Geoffrey M.
Published: October 2005

Seasonal variation of the vegetated land surface across tropical South America was evaluated using Trajectory Analysis (TA) on the Pathfinder AVHRR Land (PAL) NDVI data. These 8 km 10‐day maximum‐value composite images of the Normalized Difference Vegetation Index (NDVI) span nearly two decades (7/81–12/99) that include several ENSO warm/cold phases. The derived trajectory established a baseline to assess the effect of climatic events related to the El Niño/Southern Oscillation (ENSO) on the temporal development of the spatial dependence structure of the NDVI image time series. Results indicate that ENSO phases have significant effects on the spatial dependence structure of the land surface in Tropical South America that would be undetected, if the spatial domain of remotely sensed data were neglected. As such, TA provides an important technique for the assessment of the effects of global change and long‐term land use/land cover transformations on phenologies of the vegetated land surface.
Coherent excitation of a two-state system by a linearly chirped Gaussian pulse
Authors: Vasilev G. S. , Vitanov N. V.
Published: October 2005

This work presents an analytic description of coherent excitation of a two-state quantum system by an external field with a Gaussian temporal shape and a linear frequency sweep. A very accurate analytic approximation to the transition probability in terms of the Lambert function is derived by using the Dykhne-Davis-Pechukas approach. This approximation provides analytic expressions for the frequency and the amplitude of the probability oscillations and for the ranges of interaction parameters where high transition probability is obtained.
Vibrational energy transfer in N2–N2 collisions: A new semiclassical study
Authors: Cacciatore M. , Kurnosov A. , Napartovich A.
Published: October 2005

The vibrational energy relaxation in collisions between N2 molecules in the low- and medium-lying vibrationally excited levels was revisited using the semiclassical coupled-state method and the use of two different potential-energy surfaces having the same short-range potential recently determined from ab initio calculations but with different long-range interactions. Compared to the data reported in the classical work by Billing and Fisher [Chem. Phys. 43, 395 (1979)], the newly calculated vibration-to-translation rate constant K(1,0∣0,0) is in much better agreement with the available experimental data over a large temperature interval, from T=200K up to T=6000K. Nevertheless, as far as the vibration-to-translation exchanges are concerned, the lower-temperature regime remains quite critical in that the new rate constants do not completely account for the rate constant curvature suggested by the experiments for temperatures lower than T=500K. The dependence of the state-selected vibration-to-vibration rate constants, K(v,v−Δv∣0,1), both upon the vibrational quantum number v and the gas temperature are calculated. The substantial deviations from previously found behaviors could have major consequences for the vibrational kinetic modeling of N2-containing gas mixtures.
Calculation of specific, highly excited vibrational states based on a Davidson scheme: Application to HFCO
Authors: Iung Christophe , Ribeiro Fabienne
Published: October 2005

We present the efficiency of a new modified Davidson scheme which yields selectively one high-energy vibrationally excited eigenstate or a series of eigenstates. The calculation of a highly vibrationally excited state ψ located in a dense part of the spectrum requires a specific prediagonalization step before the Davidson scheme. It consists in building a small active space P containing the zero-order states which are coupled with the zero-order description of the eigenstate of interest. We propose a general way to define this active space P which plays a crucial role in the method. The efficiency of the method is illustrated by computing and analyzing the high-energy excited overtones of the out-of-plane mode ∣6,8,10ν6⟩ in HFCO. These overtone energies correspond to the 234th, 713th, and 1774th energy levels in our reference basis set which contains roughly 140 000 states. One of the main advantages of this Davidson scheme comes from the fact that the eigenstate and eigenvalue convergence can be assessed during the iterations by looking at the residual ∥(H−EM)ψM∥. The maximum value ϵ allowed for this residual constitutes a very sensitive and efficient parameter which sets the accuracy of the eigenvalues and eigenstates, even when the studied states are highly excited and are localized in a dense part of the spectrum. The physical analysis of the eigenstates associated with the 5th, 7th, and 9th out-of-plane overtones in HFCO provides some interesting information on the energy localization in this mode and on the role played by the in-plane modes. Also, it provides some ideas on the numerical methods which should be developed in the future to tackle higher-energy excited states in polyatomics.
Effect of Al and Si substitutions on the magnetic properties of SmTbFe17
Authors: Ingersoll J. C. , Markandeyulu G. , Murty V. S. , Rama Rao K. V. S.
Published: October 2005

The structural and magnetic properties of SmTbFe17−xAlx (x=0–8) and SmTbFe17−xSix (x=0–3.5) were investigated by x-ray-diffraction and magnetization studies. All the compounds stabilize in rhombohedral structure. The lattice parameters are found to increase with Al substitution whereas they are found to decrease with Si substitution. The rates of the decrease of saturation magnetization (Ms) value with the substitution of Al and Si are almost the same. The easy direction of magnetization (EMD) is in the ab plane up to an Al concentration of x=7 and has a tendency to shift towards the c axis at x=8. All the compounds with Si are seen to have the EMD in the ab plane. Electron-magnon scattering is seen to contribute to the electrical resistivity in both Al- and Si-substituted compounds; in the temperature range of 30–60K and at higher temperatures, scattering due to phonons is observed.
A unified decay formula for luminescence decays
Authors: Weon Byung Mook , Lee Jong-Lam , Je Jung Ho
Published: October 2005

We suggest a unified decay formula for luminescence decays in light-emitting diodes by modifying the classical stretched exponential decay. From fundamental considerations we find that the stretched exponent, which is a constant in the classical stretched exponential decay, intrinsically changes with time for luminescence decays. On this basis we develop a unified decay formula by introducing a time-dependent stretched exponent. The time dependence of the stretched exponent is attributed to the lifetime dispersion of localized excitons.
Compton scattering of elemental silicon at high pressure
Authors: Tse J. S. , Klug D. D. , Jiang D. T. , Sternemann C. , Volmer M. , Huotari S. , Hiraoka N. , Honkimäki V. , Hämäläinen K.
Published: October 2005

The electronic structure of elemental silicon has been studied under high pressure using high-energy Compton scattering utilizing synchrotron radiation. The experiment was realized using a special Laue monochromator and a novel assembly of compound refractive lenses. The extremely good focusing enabled us to utilize a Mao–Bell version of the Merrill–Basset diamond anvil cell with a Be gasket up to a pressure of 20 GPa. After the careful subtraction of background scattering, the Compton profile difference for the metastable Si-XII to the Si-V phase was extracted and compared with the theory. The results clearly demonstrate the feasibility and potential of the Compton scattering technique as a complementary tool in the study of electronic structure of materials under high pressure.
Self-regenerative field emission source
Authors: Tanemura Masaki , Tanaka J. , Itoh K. , Okita T. , Miao L. , Tanemura S. , Lau S. P. , Huang L. , Agawa Y. , Kitazawa M.
Published: October 2005

A self-regenerative field emission source was demonstrated. The emission source (cathode) consisted of carbon nanofibers (CNFs) grown on the tip of conical carbon protrusions on a graphite plate. CNFs were ∼25nm in diameter, 0.3–2.5μm in length and ∼1×106mm−2 in site density. Initial emission characteristics showed a threshold field of 3.05V∕μm with a current density of 1μA∕cm2 and a field enhancement factor of 2860 from the Fowler-Nordheim plot assuming the work function of 4.6 eV for graphite. A lifetime test carried out for more than 40 h at a constant applied electric field of 10V∕μm in 10−4Pa region disclosed a stable emission with a current density of 1.7–3.0×10−4A∕cm2 after a slight initial decrease in the emission current. Detailed morphological observations revealed that a thick layer of newly grown carbon fibers was formed on the cathode surface after the lifetime test which could be responsible for the observed stable and long-sustained emission under a nonultrahigh vacuum condition. Their growth was attributed to the surface diffusion of carbon atoms generated by sputtering of the carbon cathode with ionized residual gas molecules during the field emission process. Thus, the CNF-tipped carbon emitter was believed to be promising as a practical field electron emission source used under low vacuum.
In situ formation of a gel microbead for indirect laser micromanipulation of microorganisms
Authors: Ichikawa Akihiko , Arai Fumihito , Yoshikawa Keiichi , Uchida Tomoyuki , Fukuda Toshio
Published: October 2005

We propose the in situ formation of gel microbeads made of a thermoreversible hydrogel for indirect laser micromanipulation of microorganisms. Irradiation, using a 1064nm laser, of an aqueous solution mixed with poly-(N-isopropylacrylamide) through a high magnification lens resulted in the formation of a gel microbead at the laser focus due to heating. The gel microbead is trapped by the laser, and is used for indirect laser micromanipulation of microorganisms. However, the laser power used to form the bead is generally too strong to perform manipulation in a stable manner. In this letter we show a method to reduce the laser power to form a gel microbead using the poly-(N-isopropylacrylamide) aqueous solution by the addition of additives. The gelation temperature and the laser absorption rate of the solution in the presence of several different additives were investigated. We selected YPD (yeast extract, peptone, dextrose) broth as an additive and measured the relationship between the laser power, irradiation time, and diameter of the gel microbead. We succeeded in reducing the laser power for gel microbead formation, and in using the laser-trapped gel microbead for the manipulation of a yeast cell and DNA.
Signal enhancement of the in-plane and out-of-plane Rayleigh wave components
Authors: Edwards R. S. , Jian X. , Fan Y. , Dixon S.
Published: October 2005

Several groups have reported an enhancement of the ultrasonic Rayleigh wave when scanning close to a surface-breaking defect in a metal sample. This enhancement may be explained as an interference effect where the waves passing directly between source and receiver interfere with those waves reflected back from the defect. We present finite element models of the predicted enhancement when approaching a defect, along with experiments performed using electromagnetic acoustic transducers sensitive to either in-plane or out-of-plane motion. A larger enhancement of the in-plane motion than the out-of-plane motion is observed and can be explained by considering ultrasonic reflections and mode conversion at the defect.
Global Standards and Emerging Markets: The Institutional-Investment Value Chain and the CalPERS Investment Strategy
Authors: Hebb Tessa , Wójcik Dariusz
Published: October 2005

Institutional investors, particularly pension funds, based in developed Anglo-American capital markets are increasingly investing in international markets, including emerging markets, in an effort to capitalize on the rapid growth rates of these markets. But investment in far-flung jurisdictions carries with it risk and uncertainty, particularly when the corporate standards of firms in emerging markets are below those found in these investors' home countries. In order to mitigate the risks posed by poor corporate standards of behaviour, institutional investors increasingly apply nonfinancial criteria not only to individual firms in emerging markets, but to the corporate practices of whole countries. Though countries and their regulatory regimes are central to external capital-investment decisions, we find convergence to global standards occurs when key actors in the investment value chain demand levels of corporate and social behavior greater than those currently consistent with countries' own regulatory frameworks. We test this hypothesis using the decision of the California Public Employees Retirement System to screen out several emerging-market countries from their investment portfolio on the basis of a variety of nonfinancial criteria.
An exploratory study of physiological correlates of neurodevelopmental delay in infants with sickle cell anaemia
Authors: Hogan Alexandra M. , Kirkham Fenella J. , Prengler Mara , Telfer Paul , Lane Roderick , Vargha‐Khadem Faraneh , de Haan Michelle
Published: October 2005

This study aimed to investigate whether infants with sickle cell anaemia (SCA) are at risk of neurodevelopmental delay, and whether any delay is associated with SCA pathology. Twenty‐eight infants (14 SCA; 14 age‐ and ethnic‐similar controls) were assessed longitudinally with the Bayley Infant Neurodevelopmental Screener (BINS) at 3, 9 and 12 months. Transcranial Doppler (TCD) and pulse oximetry (SpO2) measures were recorded longitudinally in SCA infants, and a subgroup of controls. Haemoglobin values were obtained from SCA infants. At each age, SCA infants obtained BINS scores indicative of greater risk of neurodevelopmental delay compared with controls. The number of moderate–high BINS risk scores increased significantly between 3 and 9 months. At 9 months BINS raw scores correlated negatively with TCD velocity and positively with haemoglobin. This exploratory study suggests that SCA infants may be at greater risk of neurodevelopmental delay than previously considered, and may provide the impetus for further research into the very early precursors of cognitive impairment.
A comparison of benthic macroinvertebrate assemblages among different types of alpine streams
Authors: HIEBER MÄGGI , ROBINSON CHRISTOPHER T. , UEHLINGER URS , WARD J. V.
Published: October 2005

1. Benthic macroinvertebrate assemblages were compared among a diverse array of first‐order alpine tundra streams of the Swiss Alps.

2. A principal components analysis separated sites into three main groups: rhithral streams, rhithral lake outlets, and kryal sites including outlets and streams. Rhithral streams contained the most diverse and taxon rich assemblages, being colonised by both non‐insect taxa and Ephemeroptera, Plecoptera, Trichoptera and Diptera.

3. Rhithral lake outlets supported high densities of non‐insect taxa such as Oligochaeta, Nemathelminthes and crustaceans. Despite low taxon richness, kryal sites had high Ephemeroptera and Plecoptera abundances. Chironomidae were most common at all sites.

4. Collector‐gatherers were dominant at all sites, whereas filter‐feeders were rare. Scrapers and shredders were more common in streams than lake outlets.

5. Water temperature and algal standing crops were higher at rhithral lake outlets than rhithral streams, perhaps providing more favourable habitat for non‐insect taxa. Glacial runoff was the dominant factor influencing macroinvertebrate assemblages of kryal streams and kryal lake outlets. Alpine lakes influenced the environmental conditions of their outlets and, consequently, their macroinvertebrate assemblages unless being constrained by a glacial influence.
Response of the fish community to human‐induced changes in the Biobío River in Chile
Authors: HABIT EVELYN , BELK MARK C. , CARY TUCKFIELD R. , PARRA OSCAR
Published: October 2005

1. The Biobío River basin of south‐central Chile exhibits the greatest species richness of all rivers in Chile, where it is one of the most important rivers for human use. Use for provision of drinking water, irrigation, sewage effluents, hydropower generation and industry has increased dramatically during the last decade. To help understand the effects of human activities on the Biobío River, we document recent changes in the fish community.

2. In this study, current patterns of distribution and abundance of fishes were compared with the expected longitudinal pattern, and to historical data from studies conducted before the rapid development of the last decade. Fish distribution, biomass, abundance and diversity were studied at eight sampling stations in the middle and lower zones of the river in both high and low flow seasons.

3. Contrary to the pattern observed in less impacted river systems, species richness (S), diversity (H′) and abundance [calculated catch per unit effort (CPUE)] all tended to decrease downstream from the uppermost sampling locations. Mean S decreased from 7.9 to 5.4, mean H′ decreased from 0.7 to 0.4, and mean CPUE decreased from 111 to 43 from hyporithral to potamal locations.

4. Comparison with previous records indicates loss or reduction in distribution of native species, and a concurrent expansion in distribution and abundance of tolerant introduced species (e.g.Gambusia holbrooki, andCyprinus carpio) over the last 10–15 years. These comparisons suggest a large‐scale and long‐term effect of recent human impacts on the river.
Dry‐pasteurization of egg albumen powder in a fluidized bed. II. Effect on functional properties: gelation and foaming
Authors: Hammershøj Marianne , Rasmussen Hans C. , Carstens Jan H. , Pedersen Henrik
Published: October 2005

Dry‐pasteurization of egg albumen (EA) powder in a fluidized bed was studied in two experiments. Experiment 1 consisted of two different temperatures (90 and 130 °C) and experiment 2 of two air moisture levels (high and low). Powders were processed from 10 min to 3 h. The reference treatment was traditional pasteurization at 90 °C for 21 h. The fluidized bed treatment effects on gel texture, water‐holding capacity (WHC), protein binding, gel colour, foaming capacity, foam stability and surface pressure were evaluated. Gels of EA powders treated at high temperature and high air moisture levels exhibited higher stress, strain and WHC values than gels of untreated EA powder. The gel colour became significantly darker, greener and less yellow by fluidized bed treatment. Foaming and surface activity properties were un‐affected by the treatments, however, foam stability against liquid drainage correlated positively with surface pressure.
Resilience and resistance of ecosystem functional response to a precipitation pulse in a semi‐arid grassland
Authors: POTTS DANIEL L. , HUXMAN TRAVIS E. , ENQUIST BRIAN J. , WELTZIN JAKE F. , WILLIAMS DAVID G.
Published: October 2005

In water‐limited ecosystems, discrete precipitation events trigger brief but important episodes of biological activity. Differential responses of above‐ and below‐ground biota to precipitation may constrain biogeochemical transformations at the ecosystem scale.

We quantified short‐term dynamics of whole ecosystem response to 39 mm irrigation events (precipitation pulses) during June 2002 and 2003 using plant physiological and ecosystem gas‐exchange measurements as state variables in a principal components analysis (PCA). Experimental plots consisted of either native (Heteropogon contortus L.) or non‐native (Eragrostis lehmanniana Nees) bunchgrasses planted in monoculture on two distinct geomorphic surfaces in a semi‐arid grassland.

For 15 days, treatments followed similar, non‐linear trajectories through state variable space with measurement periods forming distinct clusters; PCA axes 1 and 2 combined to explain 80.7% of the variation during both 2002 and 2003.

During both years, bunchgrass species interacted with soil type such that there was a reduction in ecosystem functional resistance in plots planted with the non‐native bunchgrass species on the fine‐textured clay geomorphic surface.

System‐level hysteresis, emerging as a result of independent responses of photosynthesis, respiration and evapotranspiration to precipitation, indicated the potential for alternative functional states.

Quantifying the frequency and duration of ecosystem alternative functional states in response to individual precipitation events within a season will provide insights into the controls of species, soils and climate on ecosystem carbon and water cycles.
Effects of litter and standing biomass on growth and reproduction of two annual species in a Mediterranean old‐field
Authors: VIOLLE CYRILLE , RICHARTE JEAN , NAVAS MARIE‐LAURE
Published: October 2005

We tested the hypothesis that the competitive ability of a plant changes during its lifetime, by evaluating variations in the relative influence of standing biomass and litter on plant performance.

Seedlings of two annual herbaceous species (‘targets’), of contrasted life‐forms (Crepis foetida and Bromus madritensis) were transplanted into an old‐field. The competitive ability of seedlings, vegetative and reproductive plants towards neighbours was recorded over one growing season.

Fourteen traits related to plant morphology, growth and reproduction were measured to assess the competitive ability of targets. Relationships among traits were characterized to identify a set of traits as a surrogate of target competitive ability.

The two target species responded similarly. Early growth was facilitated by litter and, to a greater degree, by vegetative biomass. Thereafter, the effect of neighbouring vegetation on target performance was negative, with a maximum depressing effect on reproduction (especially seed number and date of flowering) despite a weak facilitative effect of litter. Plant basal diameter, measured at peak growth period, and total number of inflorescences per plant, were found to predict growth and reproductive components of competitive ability, respectively.

Assessing the effects of competition for population success from the response of vegetative plants will underestimate its importance because competition appears to exert its maximal impact on seed production.
Cost and mitigation of insecticide resistance in the maize weevil, Sitophilus zeamais
Authors: Guedes R. N. C. , Oliveira E. E. , Guedes N. M. P. , Ribeiro B. , Serrão J. E.
Published: October 2005

Abstract.  A common assumption in models of insecticide resistance evolution is the association between resistance and fitness costs in the absence of insecticides. There is empirical evidence of such associations, but their physiological basis (and mitigation) is little investigated. Pyrethroid‐resistant populations of the maize weevil Sitophilus zeamais (Coleoptera: Curculionidae) offer this opportunity. Pyrethroid resistance in this species was initially observed in five Brazilian states by 1995, but the phenomenon apparently decreased and did not spread to other regions, probably due to the occurrence of a fitness disadvantage in resistant individuals in the absence of insecticides. The present investigation aims to verify whether differences in respiration rate and fat body morphology are related to differences in rate of development in Brazilian populations of S. zeamais resistant to insecticides, and thereby provide evidence for the existence (or not) of a physiological fitness cost acting against insecticide resistance in maize weevils. This may occur due to a possible energy trade‐off between insecticide resistance and other physiological processes associated with development and reproduction. To achieve this, studies of the rate of development, respiration and fat body cytomorphology are carried out in one insecticide‐susceptible (from Sete Lagoas) and two resistant populations (from Jacarezinho and Juiz de Fora) of S. zeamais. The resistant population from Jacarezinho shows that higher body mass is associated with higher energy reserves (larger trophocyte area) for development and reproduction, as well as for insecticide resistance. However, the resistant population from Juiz de Fora does not appear to have large enough energy allocation for insecticide‐resistance expression and development and/or reproductive performance, suggesting a trade‐off between resistance and other life history traits.
Temporal constraints on the growth and decay of large‐scale mobilized mud masses and implications for fluid flow mapping in sedimentary basins
Authors: Jackson Christopher , Stoddart Daniel
Published: October 2005

Seismic‐stratigraphic analysis of the Cretaceous to succession of the Uer Terrace, North Sea seabed Basin, Norway, demonstrates that the Upper Oligocene succession has undergone large‐scale mobilization of mudstone‐dominated units due to the upward migration of water and associated hydrocarbons into the interval, which is in some way linked to a period of gas expulsion from adjacent deep basins. Seismic‐stratigraphic analysis of units overlying the mobilized zones indicates they created positive seafloor topography during the Late Miocene implying gaseous fluids were expelled at the seabed. Loading by the overlying Pliocene succession caused the mobilized mud masses to deflate and resulted in the formation of low‐relief, fault‐bounded craters. The results of this study have implications for understanding the location and timing of fluid flow in sedimentary basins.
Altered gene silencing and human diseases
Authors: Perini G , Tupler R
Published: October 2005

Epigenetic regulation of gene expression is mediated through several mechanisms, including modifications in DNA methylation, covalent modifications of core nucleosomal histones, rearrangement of histones and RNA interference. It is now clear that deregulation of epigenetic mechanisms cooperates with genetic alterations in the development and progression of several Mendelian disorders. Here, we summarize the recent findings that highlight how certain inherited diseases, such as Rett syndrome, Immunodeficiency–centromeric instability–facial anomalies syndrome, and facioscapulohumeral muscular dystrophy, result from altered gene silencing.