bluuebunny/crossref_metadata_2025 huggingface dataset:
A frequency offset compensation scheme for the received signal under the influence of Rician fading channels with a direct component shifted by Doppler effect
Authors: Asahara Takashi , Kojima Toshiharu , Miyake Makoto
Published: October 2002

A scheme that estimates and compensates for the frequency offset from the phase rotation of pilot symbols is proposed as a carrier frequency offset compensation scheme that periodically inserts pilot symbols in the transmitted signal. Since the frequency offset is estimated and compensated for at a frequency close to the direct path wave when a conventional scheme is applied in a Rician fading environment where the direct path wave is Doppler shifted, the Doppler spread appears to widen further, the estimation error of the fading distortion increases, and the error rate performance degrades. In this paper, we propose a frequency offset compensation scheme that estimates the center frequency of the Doppler spread and reduces the effects of the Doppler‐shifted direct path wave by (1) calculating the signal power in the frequency domain by taking the discrete Fourier transform (DFT) of the pilot symbols and (2) smoothing the signal power in a frequency window. Computer simulations demonstrate the superior error rate performance of the proposed scheme compared to the conventional scheme and clearly show its effectiveness. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(12): 65–75, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10006
Conditions of half‐frequency oscillation in high‐power amplifier with FET and its suppression method using quarter‐wavelength open‐circuited stub
Authors: Uchida Hiromitsu , Itoh Yasushi , Miyazaki Moriyasu , Urasaki Shuji
Published: October 2002

With regard to the half‐frequency oscillation observed in the nonlinear operation of a microwave power amplifier based on FETs, the voltage and current of the FET in a large‐signal mode at an excitation frequency of 2f0 are expanded as Fourier series in half this frequency, that is, f0. Then, the condition that the Fourier coefficient for the f0 component is nonzero, namely, the condition of half‐frequency oscillation, is derived. It is shown that the half‐frequency oscillation takes place when the determinant is zero for the matrix defined by the fundamental excitation components and time averages of the gate‐to‐source capacitance, mutual conductance, and drain conductance, as well as the load impedance condition at frequency f0. Also, a method for suppression of the half‐frequency oscillation by connecting an open stub one‐quarter wavelength long at the half‐frequency to the output side of the FET is proposed, and its effectiveness is confirmed by experiment. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(6): 11–19, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10008
Two‐dimensional parallel optical interconnect module formation based on microoptical bench concept
Authors: Aoki Yasuhiko , Shimada Yuji , Koyama Fumio , Iga Kenichi
Published: October 2002

Parallel optical interconnect technology is arousing high hopes for applications to very short reaches between optical communication transmission devices and to interconnection between high‐speed computers. However, no sufficient study has been carried out on the integration technology for two‐dimensional array‐type optical components, which are indispensable for large‐scale integration of the optical components used for parallel optical interconnects. This paper presents a method of integration of parallel optical components, using the microoptical bench (MOB) proposed by the authors as an integration technique for two‐dimensional array‐type optical components, together with characteristic evaluation of the planar microlens, as the key component, and an extension of the parallel optical interconnect module using wavelength division multiplexing. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(7): 30–36, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10027
Realizing eye movement in reading
Authors: Ishihara Yukio , Morita Satoru
Published: October 2002

A feature of human viewpoint movement in reading English has been pointed out from the psychological aspect, namely, that the first viewpoint on the word concentrates at the center of the word. This paper focuses on the three factors that seem to induce the above feature of viewpoint movement in reading English, which are the use of foveal vision, the use of the edge density of letters (characters), and the use of the space between words. The movement of the viewpoint is realized on a computer, and the major factor responsible for the feature that the viewpoint concentrates at the center of the word is examined. The attention region is defined in realizing viewpoint movement that is restricted. The viewpoint is actually moved for the cases where each of the three factors is followed or not followed, and the features of viewpoint movement are examined. The features of viewpoint movement realized on the basis of each factor are compared to those of previously reported human viewpoint movement. Based on the comparison, it is shown that the three factors are actually inducing the feature that the viewpoint concentrates at the center of the word. By varying the size of the attention region, the effect on the viewpoint movement is examined, and it is shown that the size of the attention region is the factor that manifests the features of human viewpoint movement. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(8): 34–43, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10064
The effect of an externally applied radio‐frequency electromagnetic field on the performance of a disk MHD generator
Authors: Fujino Takayasu , Watanabe Yukihiro , Okuno Yoshihiro , Yamasaki Hiroyuki
Published: October 2002

The effects of an externally applied radio‐frequency (rf) electromagnetic field on the nonequilibrium performance of a disk MHD generator were examined experimentally. As a preliminary experiment, plasma production by the applied rf electromagnetic field was attempted in the disk generator (Disk‐PIA), in which rf induction coils were embedded in the one‐side disk wall, under the conditions of no seeding, no flow, and no magnetic field. From the results of the preliminary experiment, it was confirmed that the argon plasma (∼110 Torr) was produced uniformly in the azimuthal direction by the rf electromagnetic field even in the presence of exposed anodes in the faced disk wall and metallic support at the disk center. In MHD power generation experiments with the Disk‐PIA installed in the shock‐tube facility, the increase in the electrical output and more indiscrete discharge attributed to the rf electromagnetic field were verified with good reproducibility for the first time. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(4): 46–53, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10009
Quantitative analysis of the influence of conductors and ferromagnetic structures in power facilities on an ELF magnetic field environment using the finite element method
Authors: Kato Katsuji , Goto Naoki , Uga Yuji , Shimizu Masaji , Yoshida Akio , Okubo Hiroshi
Published: October 2002

Recently, electric power transmission/substation systems need to be extended and they tend to be more compact. From the backgrounds of electromagnetic field environment, especially the magnetic field environment in and around electric power facilities becomes more important. However, many factors must be considered when investigating it, such as complicated current conditions, configurations of conductors and ferromagnetic structures, and so on. For more precise investigation of magnetic field environments, we must understand the quantitative influence of conductors and ferromagnetic structures.

In this paper we describe how conductive and ferromagnetic materials influence the ELF magnetic field distribution. We carried out the measurement and finite element analysis of magnetic flux density distribution around an aluminum plate, a soft magnetic iron plate, and a 1/40 reduced model of an actual transmission tower. Based on the results, we clarified the influence of conductors and ferromagnetic substances on the magnetic flux density distribution around them. Finally, we showed the effectiveness of finite element analysis for evaluating the magnetic field around actual power facilities. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(3): 44–52, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10021
A transmission line fault‐location system using the wavelet transform
Authors: Hisakado Takashi , Tanaka Kohji , Okumura Kohshi
Published: October 2002

This paper describes the locating system of line‐to‐ground faults on a transmission line by wavelet transform. The possibility of the location with the surge generated by a fault has been theoretically proposed. In order to make the method practicable, we realize very fast processors. We design wavelet transform and location chips, and construct a very fast fault location system by processing the measured data in parallel. This system is realized by a computer with three FPGA processor boards on a PCI bus. The processors are controlled by UNIX and the system has the graphic user interface with X window system. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(4): 27–37, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10040
Improvement of performance of disk MHD generator with argon by introduction of swirl
Authors: Torii Syunsuke , Tsutsumi Masashi , Okuno Yoshihiro , Yamasaki Hiroyuki
Published: October 2002

An experimental study of performance of the disk MHD generator with argon was carried out using a shock‐tube driven facility. An inlet swirl was introduced in the MHD channel in order to improve the enthalpy extraction and the isentropic efficiency. The experimental results were compared with those of the disk MHD generator without the inlet swirl. A high enthalpy extraction of 25.7% was obtained and the highest isentropic efficiency for argon was achieved at the same time in the present experiment. The measured static pressure in the MHD channel was kept lower than that without the inlet swirl. This has suggested that the introduction of the inlet swirl reduces the retarding force for the flow and that the increase of the enthalpy extraction is ascribed to the increase of the flow velocity and of the electrical efficiency. Furthermore, the flow without shock wave was observed at low seed fractions and low load resistances. At the same time, it was found for the first time that when there was no shock wave, the isentropic efficiency became higher than that with the shock wave. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(1): 18–25, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10045
Performance evaluation of continuous levitation in an active‐maglev system using YBCO bulk and multiple electromagnets
Authors: Ueda Hiroshi , Hayashi Hiroki , Ishiyama Atsushi , Tsuda Makoto
Published: October 2002

We have designed and constructed a new type of active‐maglev system using YBCO bulk and two electromagnets and have demonstrated that levitation height was remarkably improved by continuous levitation. In the active‐maglev system, however, the upper and lower coils differed in the coil size and an iron plate beneath the lower coil was used to enhance the magnetic field around the bulk. Considering the real application to maglev transporter in the axial direction, we must realize continuous leviation using a larger number of electromagnets without such iron plate and enable the levitation height to be controlled freely. In this paper, we demonstrate continuous levitation while controlling the leviation height using three‐ and five‐electromagnet systems and investigate electromagnetic behavior within the bulk using an FEM computer program. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(2): 25–33, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10055
A multi‐agent approach to unit commitment
Authors: Nagata Takeshi , Ohno Masumi , Sasaki Hiroshi , Fujita Hideki
Published: October 2002

This paper proposes a multiagent system to power system unit commitment problems. Multiagent is a new paradigm for developing software applications. Coordinating the behavior of autonomous agents is a key issue in agent‐oriented programming techniques today. Recently, agents are being used in an increasingly wide variety of applications, ranging from comparatively small systems such as E‐mail filters to large, open, complex systems such as air traffic control. Though some agent frameworks have been proposed in the power system field, the number of studies is limited.

In this paper, we developed a power system unit commitment application by multiagent architecture. Our multiagent system has the following characteristics: (1) The system consists of a single facilitator agent, two mobile agents, and one or more generator agents which are elements of power system network. (2) The facilitator agent is developed to act as a manager for the process by using the singleton design pattern. The mobile agents migrate to generator‐agents to increase or decrease their power generations. The generator agents have their operational data. (3) Message object is developed to communicate between the agents using KQML‐like object. The proposed approach is applied to a simple model system, and the results show that the multiagent system is an efficient decentralized approach for solving power system unit commitment problems. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(2): 41–47, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10057
Development of TCSC application to fault current limiters
Authors: Yamazaki Yuji , Sugimoto Shigeyuki , Ogawa Shigeaki , Konishi Hiroo , Kikuchi Akira
Published: October 2002

A new Fault Current Limiter (FCL) is proposed which consists of a conventional Current Limiting Reactor (CLR) and a Thyristor‐Controlled Series Compensator (TCSC) in series. In normal operation, it works to compensate for impedance of the CLR and a line, while it limits short‐circuit currents during system faults. After the fault clearance, it damps power oscillations. Effectiveness of fault current suppression and damping effects on power system oscillations were studied by digital simulations and by an analogue simulator. It was found that the proposed FCL could decrease impedance of a conventional CLR reactor due to inductive impedance of the TCSC and have good damping characteristics. From investigation of cooperative protection system for the FCL, it showed that fast bypasses of the thyristors in the TCSC were useful for overvoltage protection, fault current limit and decrease in capacity of protective arresters connected in parallel with the TCSC. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(3): 53–60, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.2004
Climate protection through tradable permits: the EU proposal for a CO2 emissions trading system in Europe
Authors: Gagelmann Frank , Hansjürgens Bernd
Published: October 2002

On 23 October 2001 the European Commission adopted a proposal for a directive for trade in greenhouse gas emissions. Following the US experience of emissions trading systems, this marks the first large‐scale attempt to deploy this instrument of environmental policy in Europe. The proposal places European climate protection policy on a completely new footing. The prospects of its implementation have increased since the climate change conference in Marrakech.

This paper introduces the draft directive and gives an initial economic appraisal. It concludes that the directive deliberately—and wisely—limits the scope of the first trading phase, starting in 2005. Consequently, there is still considerable scope for increasing its efficiency (resulting from gains from trading) in later phases, namely by extending both the number of participants and the gases included. The number of participants in the first phase and the institutional arrangements, however, appear sufficient to enable a liquid, functioning market. In this respect, the (politically difficult) decision to start with a compulsory system is also to be welcomed.

Important issues not yet sufficiently clarified include the concrete rules for defining the total permit quantity issued to participants by each member state, and whether other economic sectors, which are to be treated by ‘other policies and measures’, will bear a comparable burden. Furthermore, the essential questions of primary allocation and treatment of newcomers—which are in principle left up to member states—as well as the linkage of emissions trading with existing policies affecting the participating sectors must be solved before legal implementation is recommended. Copyright © 2002 John Wiley & Sons, Ltd and ERP Environment.
The developmental approach to young children's strategic social cognition and behaviour
Authors: Leonova Tamara , Dubois Nicole
Published: October 2002

This study explores the development of strategic behaviour related to kindness and intelligence dimensions in 3‐ to 8‐year‐old children. Previous research systematically highlighted the affective bias that limited young children's thinking and behaving in strategic terms. We argue that young children are able to grasp specific dimensions of social affordances from personality traits and behaviour exemplifying these traits. The results obtained in the partner choice paradigm revealed a developmental increase in social utility understanding. This supports our hypothesis of early social affordances understanding and provides empirical evidence that affective bias did not drastically influence strategic partner choice in 4‐ to 8‐year‐old children. Copyright © 2002 John Wiley & Sons, Ltd.
Aroclor 1254 alters morphology, survival, and gene expression in Xenopus laevis tadpoles
Authors: Jelaso Anna M. , Lehigh‐Shirey Elisabeth , Predenkiewicz Amy , Means Jay , Ide Charles F.
Published: October 2002

PCBs are persistent environmental contaminants that cause a variety of adverse health effects in wildlife and humans. This article describes the use of signature gene expression patterns that link increased PCB exposure with progressive, adverse biological effects. Developing Xenopus laevis tadpoles of two age classes were exposed to the PCB mixture Aroclor 1254 for 2 days. Real‐time PCR was used to quantitate mRNA expression for 11 physiologically relevant, potential bioindicator genes. Younger tadpoles (5 days postfertilization) were resistant to Aroclor 1254 and showed few changes in gross morphology, swimming behavior, survival, or gene expression. Older tadpoles (11 days postfertilization) were more susceptible to Aroclor 1254. Exposure to 25 and 50 ppm Aroclor 1254 caused alterations in gross morphology and swimming behavior and statistically significant decreases in survival. These tadpoles showed statistically significant decreases in gene expression for 9 out of the 11 genes measured. Tadpoles exposed to 10 ppm showed incipient health changes but had gene expression profiles similar to the tadpoles treated with higher doses of Aroclor 1254. Tadpoles exposed to 1 ppm did not exhibit any observable adverse health effects, yet statistically significant decreases in gene expression occurred in these tadpoles (4 out of 11 genes). After prolonged exposure, tadpoles exposed to 1 and 10 ppm Aroclor 1254 exhibited health effects similar to those exposed to higher concentrations. Therefore, changes in expression of specific genes may serve not only as molecular bioindicators of Aroclor 1254 exposure but also as predictors of impending adverse health effects. Environ. Mol. Mutagen. 40:24–35, 2002. © 2002 Wiley‐Liss, Inc.
Determination of mechanical properties of traditional masonry walls in dwellings of Faial Island, Azores
Authors: Costa Aníbal
Published: October 2002

The determination of mechanical properties of masonry walls is a fundamental pre‐requisite for the characterization of the seismic response of traditional buildings, which helps on the definition of adequate rehabilitation and strengthening procedures.

This paper presents a testing campaign carried out in the Cedros region of Faial Island, Azores, hit by the July 98 earthquake, aiming at the determination of physical and mechanical properties of stone masonry walls, namely the mass density and Young's modulus.

The paper describes the developed testing techniques as a contribution to the study and the preservation of traditional masonry buildings. Copyright © 2002 John Wiley & Sons, Ltd.
Probabilistic analysis of peak response of MDOF systems with uncertain PSD function
Authors: Hong H. P. , Wang S. S.
Published: October 2002

The use of uniform hazard spectra which have the same probability of exceedance at different frequencies has been proposed for the future version of the National Building Code of Canada. Commonly used combination rules to estimate the peak responses of multi‐degree‐of‐freedom (MDOF) systems are the square root of sum of squares rule and the complete quadratic combination rule. However, the probability that the peak response of a MDOF system exceeds the one estimated by using these rules with the peak modal responses from the uniform hazard spectra cannot be inferred directly. The assessment of the probability of exceedance of the peak response of MDOF systems is presented by considering that the uncertainty in seismic excitation due to all potential earthquakes can be lumped in the power spectral density function of the ground acceleration with uncertain model parameters. This probability is evaluated based on the random vibration of linear systems and the first‐order reliability method. It is found that the under‐ or over‐estimations are less than about 5 or 10% if the modal contributions are not within 10–90% of, or not within 20–80% of, the absolute sum of the effective modal peak responses, respectively. Otherwise, severe under‐ or over‐estimation could result. Copyright © 2002 John Wiley & Sons, Ltd.
Geological controls on the formation of alluvial meanders and floodplain wetlands: the example of the Klip River, eastern Free State, South Africa
Authors: Tooth S. , McCarthy T. S. , Brandt D. , Hancox P. J. , Morris R.
Published: October 2002

Floodplain wetlands are common features of rivers in southern Africa, but they have been little studied from a geological or geomorphological perspective. Study of the upper Klip River, eastern Free State, South Africa, indicates strong geological controls on the formation of alluvial meanders and associated floodplain wetlands. Along this river, pronounced and abrupt changes in valley width are strongly linked to lithological variations. Where weakly cemented sandstone crops out, the Klip has laterally eroded bedrock and carved valleys up to 1500 m wide. In these valleys, the river meanders (sinuosity up to ∼1·75) on moderate gradients (<0·001) within extensive floodplains marked by numerous oxbow lakes, backswamps and abandoned channels, many of which host substantial wetlands. In contrast, where highly resistant dolerite crops out, lateral erosion of bedrock is restricted, with the Klip tending instead to erode vertically along joints or fractures. Here, valleys are narrower (<200 m), channel‐bed gradients are steeper (>0·003), the river follows a much straighter course (sinuosity ∼1·10–1·34), and floodplains are restricted in width.

Long‐term landscape development in the Klip and numerous similar catchments depends on the interaction between fluvial processes in the sandstone and dolerite valleys. In the sandstone valleys, vertical erosion rates are controlled by erosion rates of the more resistant dolerites downstream. Hence, in the short‐ to medium‐term (decades to tens of thousands of years), lateral erosion dominates over vertical erosion, with the river concomitantly planing sandstone in the channel floor and reworking floodplain sediments. The thickness of alluvial fill in the sandstone valleys is limited (<4 m), but the resultant meanders are naturally dynamic, with processes such as point bar deposition, cutoff formation and channel avulsion resulting in an assemblage of fluvial landforms. In the longer term (greater than tens of thousands of years), however, vertical erosion will occur in the sandstone valleys as the downstream dolerites are lowered by erosion, resulting in channel incision, floodplain abandonment, and desiccation of the wetlands. Identification of the geological controls on meander and wetland formation provides information vital for the design of effective management guidelines for these ecologically rich habitats, and also contributes to a better understanding of rivers that are intermediate between fully alluvial and fully bedrock. Copyright © 2002 John Wiley & Sons, Ltd.
BDMC interlaboratory cone calorimeter test programme
Authors: Urbas Joe
Published: October 2002

In the spring of 1997, seven companies and industry associations from the USA and Canada decided to sponsor the cone calorimeter interlaboratory test programme. Reproducibility and repeatability were determined for the scalar variables measured in the cone calorimeter (ASTM E1354) according to the protocol developed by the Board for the Coordination of the Model Codes. The main requirement of the protocol was that the sample irradiance should be 75 kW/m2. The purpose of the project was to assist the model building code organizations, NFPA and various other groups in the development of a system to determine degrees of combustibility of building materials. Three US and one Canadian laboratory agreed to conduct tests on 16 materials.

The results of this round robin show that the cone calorimeter, following the Board for the Coordination of the Model Codes protocol, can provide precision similar to that cited in the current cone calorimeter standards. It is recommended that further improvements of the standards are pursued and provisions are made to improve the quality of operation of the cone calorimeter in commercial laboratories to maintain and possibly improve its repeatability and reproducibility. Copyright © 2002 John Wiley & Sons, Ltd.
NEPA and Terrorism: Is It Time for a Paradigm Shift?
Authors: Eccleston Charles H.
Published: October 2002

Most National Environmental Policy Act (NEPA) documents and other similar planning processes have

tended to focus almost exclusively on “environmental” issues. Yet, today we find ourselves facing new

problems and issues as we combat the war on terrorism. This article illustrates how NEPA and other similar

planning processes can provide an essential key in helping to safeguard the nation's homeland from

terrorism. As the reader will soon see, NEPA and other similar planning processes provide virtually all the

essential elements necessary for performing a comprehensive, rigorous, and scientifically based process for

planning for, scoping, and identifying potential terrorist scenarios, evaluating their impacts, and developing

alternatives and mitigation measures that can reduce or eliminate potential threats to high‐value

terrorist targets. In particular, “standard” accident analyses provide a nearly perfect mechanism for

performing the analysis of potential terrorist attacks. © 2002 Wiley Periodicals, Inc.
An Effective Approach for Landfill Closure, Cap Design Optimization, and Cost Analysis Using MODFLOW and the HELP Model
Authors: Fouda Ahmed , Jankauskas Brian , Martin Dan , Lewis Thomas
Published: October 2002

This article presents a design approach that has been developed and used on actual projects for a landfill

closure plan, including a slurry wall, a leachate collection system, and cap design. A relationship exists between

the cost of each of these landfill closure constituents and their impact on improving the site environmental

condition. The slurry wall is constructed to prevent leachate migration off‐site. The leachate collection

system reduces water mounding and conveys the on‐site leachate to a treatment plant. The cap decreases the

infiltration rate of stormwater into the landfill, dependent on the cap shape, area, and vertical constituents

reducing permeability. Consequently, the leachate disposal cost decreases and the maximum elevation of the leachate

mound inside the landfill is lowered; however, the cap cost increases. This article presents a cost comparison

analysis of the cap cost and the leachate disposal cost versus the cap area. The purpose of the analysis is to

optimize the project construction cost and get the best environmental results possible by cleaning up the site. The

HELP model (U.S. Environmental Protection Agency) is used to evaluate different cap alternatives

including the existing condition (no‐cap scenario, only a topsoil cover). MODFLOW (U.S.

Geological Survey) is used to develop a groundwater model. The model is used as a design tool, to demonstrate

the establishment of inward hydraulic horizontal and vertical gradients into the site resulting from the proposed

design and to study the effect of different cap areas on the leachate mound. The site environmental and economic

balance is then summarized in a graph showing cap cost, leachate disposal cost, and maximum elevation of the

leachate mound versus the cap area. Based on the graph, the optimum cap design is selected and the most feasible

action for environmental remediation is recommended. © 2002 Wiley Periodicals, Inc.
Chemical composition from volatile oil of the stem bark of Guarea macrophylla Vahl. ssp. tuberculata Vellozo (Meliaceae)
Authors: Lago João Henrique Ghilardi , Reis Anair Araújo , Roque Nídia Franca
Published: October 2002

The stem bark of Guarea macrophylla Vahl. ssp. tuberculata Vellozo (Meliaceae) was submitted to steam distillation and adsorption chromatographic separation. Seventeen sesquiterpenes, one diterpene and four fatty acids were identified using a combination of GC, GC–MS, 1H‐ and 13C‐NMR. Copyright © 2002 John Wiley & Sons, Ltd.
Object‐oriented parallel algorithms for computing three‐dimensional isopycnal flow
Authors: Concus Paul , Golub Gene H. , Sun Yong
Published: October 2002

In this paper, we derive an object‐oriented parallel algorithm for three‐dimensional isopycnal flow simulations. The matrix formulation is central to the algorithm. It enables us to apply an efficient preconditioned conjugate gradient linear solver for the global system of equations, and leads naturally to an object‐oriented data structure design and parallel implementation. We discuss as well, in less detail, a similar algorithm based on the reduced system, suitable also for parallel computation. Favorable performances are observed on test problems. Copyright © 2002 John Wiley & Sons, Ltd.
A low‐dimensional spectral approach for transient free‐surface flow inside thin cavities of symmetric shape
Authors: Zhang Sheng X. , Khayat Roger E.
Published: October 2002

The lubrication theory is extended for transient free‐surface flow of a viscous fluid inside three‐dimensional cavities of general symmetric shape but of small thickness. The problem is closely related to the filling stage during the injection molding process. The moving domain is mapped onto a rectangular domain at each time step of the computation. A modified pressure is introduced, which in this case is governed by the Laplace's equation, and it is expanded in a Fourier series along the flow direction. The expansion coefficients are obtained using the finite‐difference method. This approach is valid for simple and complex cavities as illustrated for the cases of a flat plate and a curved plate. Only a few modes are needed to secure convergence in general. It is found that the flow behaviour is strongly influenced by the shape of the initial fluid domain, the shape of the cavity, cavity thickness, and the inlet flow. Copyright © 2002 John Wiley & Sons, Ltd.
A finite volume approach for unsteady viscoelastic fluid flows
Authors: Al Moatassime Hassan , Esselaoui Driss
Published: October 2002

A finite volume, time‐marching for solving time‐dependent viscoelastic flow in two space dimensions for Oldroyd‐B and Phan Thien–Tanner fluids, is presented. A non‐uniform staggered grid system is used. The conservation and constitutive equations are solved using the finite volume method with an upwind scheme for the viscoelastic stresses and an hybrid scheme for the velocities. To calculate the pressure field, the semi‐implicit method for the pressure linked equation revised method is used. The discretized equations are solved sequentially, using the tridiagonal matrix algorithm solver with under‐relaxation. In both, the full approximation storage multigrid algorithm is used to speed up the convergence rate. Simulations of viscoelastic flows in four‐to‐one abrupt plane contraction are carried out. We will study the behaviour at the entrance corner of the four‐to‐one planar abrupt contraction. Using this solver, we show convergence up to a Weissenberg number We of 20 for the Oldroyd‐B model. No limiting Weissenberg number is observed even though a Phan Thien–Tanner model is used. Several numerical results are presented. Smooth and stable solutions are obtained for high Weissenberg number. Copyright © 2002 John Wiley & Sons, Ltd.
AGE method simulations of a turbulent far‐wake compared to spectral DNS
Authors: Bisset David K
Published: October 2002

Turbulent flow simulation methods based on finite differences are attractive for their simplicity, flexibility and efficiency, but not always for accuracy or stability. This paper demonstrates that a good compromise is possible with the advected grid explicit (AGE) method. Starting from the same initial field as a previous spectral DNS, AGE method simulations of a planar turbulent wake were carried out as DNS, and then at three levels of reduced resolution. The latter cases were in a sense large‐eddy simulations (LES), although no specific sub‐grid‐scale model was used. Results for the two DNS methods, including variances and power spectra, were very similar, but the AGE simulation required much less computational effort. Small‐scale information was lost in the reduced resolution runs, but large‐scale mean and instantaneous properties were reproduced quite well, with further large reductions in computational effort. Quality of results becomes more sensitive to the value chosen for one of the AGE method parameters as resolution is reduced, from which it is inferred that the numerical stability procedure controlled by the parameter is acting in part as a sub‐grid‐scale model. Copyright © 2002 John Wiley & Sons, Ltd.
Exact solutions of the generalized Navier– Stokes equations for benchmarking
Authors: Bourchtein Andrei
Published: October 2002

The generalized Navier– Stokes equations for incompressible viscous flows through isotropic granular porous medium are studied. Some analytical classic solutions of the Navier– Stokes equations are generalized to the case of the considered equations. Obtained solutions of generalized equations reduce to classic ones as porosity effect disappears. Average velocity of generalized solutions is calculated and evaluated in two limiting regimes of flow. In the shallow conduit, the generalized flow rate approximates the free (without porous medium) flow rate and in the case of removed boundaries this approaches Darcy's law. The use of the derived exact solutions for benchmarking purposes is described. Copyright © 2002 John Wiley & Sons, Ltd.
Factors explaining movements in the implied volatility surface
Authors: Mixon Scott
Published: October 2002

This article explores the relationship of changes in the S&P 500 index implied volatility surface to

economic state variables. Observable variables can explain some of the variation in implied volatility, with the

majority of explanatory power from index returns. Although the contemporaneous return is most important for

explaining changes in short dated volatility, the path of the index is important for explaining changes in long

dated volatility. Other variables also display statistically significant relations to volatility changes. Shocks

to the Nikkei 225, short‐term interest rates, and the corporate/government bond yield spread are

correlated with small, systematic changes in implied volatility. The results suggest a multifactor model for

market volatility, with factors other than index returns adding negligible explanatory ability. © 2002 Wiley

Periodicals, Inc. Jrl Fut Mark 22:915–937, 2002
The effect of multiple listings on the bid–ask spread in option markets: The case of Montreal Exchange
Authors: Khoury Nabil , Fischer Klaus P.
Published: October 2002

In this article, we examine the effect of multiple listings of options on their bid–ask spread, by

comparing options contracts listed only on the Montreal Exchange with those interlisted on that exchange and on a

U.S. exchange as well. Using a statistical procedure adapted to panel data and two models for the determination of

the bid–ask spread, we find that the bid–ask spreads of Montreal options interlisted in U.S. markets

are narrower than those of non‐interlisted options. That advantage tends to disappear, however, with an

increase in option price and to increase with its volatility, but is not affected by the volume of transactions in

the option market. The analysis also shows that interlisting may result in time lags in the convergence of quotes

between Montreal and the U.S. markets. Moreover, our evidence shows that with interlisting, volume shifts to the

option market where trading in the underlying security is concentrated, irrespective of the location where the

option was first introduced. © 2002 Wiley Periodicals, Inc. Jrl Fut Mark 22:939–957, 2002
Analysis of 11q21–24 loss of heterozygosity candidate target genes in breast cancer: Indications of TSLC1 promoter hypermethylation
Authors: Allinen Minna , Peri Liisa , Kujala Sonja , Lahti‐Domenici Jaana , Outila Kati , Karppinen Sanna‐Maria , Launonen Virpi , Winqvist Robert
Published: October 2002

Loss of heterozygosity (LOH) at the distal half of chromosome arm 11q is frequent in a variety of human tumors, including breast cancer, and is often associated with poor prognosis. In an ongoing attempt to locate and characterize the main target genes within this chromosome region, we first looked for aberrations in known genes either suggested to be involved in tumorigenesis or shown to suppress tumor formation. We examined 31 primary breast tumors showing LOH in 11q21–24 for mutations in the MRE11A, CHK1, PPP2R1B, and TSLC1 genes. The absence of intragenic alterations related to cancer led us next to evaluate possible gene silencing resulting from promoter region CpG hypermethylation, using the bisulfite sequencing technique. In addition to the four genes mentioned above, we also analyzed the ATM gene, which had been investigated for certain germline mutations in an earlier study. Only the TSLC1 promoter region exhibited aberrant methylation patterns, and altogether 33% (10/30) of the successfully analyzed tumors showed evidence of elevated levels of TSLC1 CpG methylation. Ten percent (3/30) of the tumors showed significantly increased methylation. Thus, as has been shown in lung and some other forms of cancer, hypermethylation of the TSLC1 promoter region is also frequently a second hit along with LOH in breast cancer. © 2002 Wiley‐Liss, Inc.
A novel gene, MDS2, is fused to ETV6/TEL in a t(1;12)(p36.1;p13) in a patient with myelodysplastic syndrome
Authors: Odero María D. , Vizmanos José L. , Román José P. , Lahortiga Idoya , Panizo Carlos , Calasanz María J. , Zeleznik‐Le Nancy J. , Rowley Janet D. , Novo Francisco J.
Published: October 2002

ETV6/TEL is the first transcription factor identified that is specifically required for hematopoiesis within the bone marrow. This gene has been found to have multiple fusion partners of which 16 have been cloned. Fluorescence in situ hybridization (FISH) analysis in a patient with myelodysplastic syndrome (MDS) revealed a t(1;12)(p36;p13) involving ETV6, with the breakpoint in this gene between exon 2 and exon 3. We report here the cloning of a novel ETV6 partner located on 1p36.1, involved in the t(1;12). 3′ RACE‐PCR from RNA identified a novel sequence fused to exon 2 of ETV6. Database searches localized this sequence in a bacterial artificial chromosome (BAC) mapped to 1p36 by fingerprint analysis. This result was confirmed by FISH using this BAC as probe. 5′ and 3′ RACE experiments with primers from this novel sequence were carried out on RNA from a healthy donor and identified a novel full‐length mRNA, which we named MDS2 (myelodysplastic syndrome 2). RT‐PCR experiments were performed on a panel of human cDNAs to analyze the expression pattern of this gene and they revealed four splicing variants. RT‐PCR analysis showed that ETV6‐MDS2, but not the reciprocal MDS2‐ETV6 fusion transcript, was expressed in the bone marrow of the patient. The product of the ETV6‐MDS2 fusion transcript predicts a short ETV6 protein containing the first 54 amino acids of ETV6 plus four novel amino acids, lacking both the PTN and the DNA‐binding domains. Possible mechanisms to account for the development of MDS in this patient are discussed. © 2002 Wiley‐Liss, Inc.
LAF4, an AF4‐related gene, is fused to MLL in infant acute lymphoblastic leukemia
Authors: von Bergh Anne R.M. , Beverloo H. Berna , Rombout Paul , van Wering Elisabeth R. , van Weel Margreet H. , Beverstock Geoffrey C. , Kluin Philip M. , Slater Rosalyn M. , Schuuring Ed
Published: October 2002

Infant acute lymphoblastic leukemia (ALL) with MLL gene rearrangements is characterized by a proB phenotype and a poor clinical outcome. We analyzed an infant proB ALL with t(2;11)(p15;p14) and an MLL rearrangement on Southern blot analysis. Rapid amplification of cDNA ends–polymerase chain reaction (PCR) and reverse transcriptase‐PCR identified the LAF4 gene mapped on chromosome region 2q11.2–q12 as a fusion partner of the MLL gene. The LAF4 gene was identified previously by its high sequence homology to the AF4 protein and encodes a protein of 1,227 amino acids. The t(4;11)(q21;q23), creating the MLL‐AF4 chimeric transcripts, is the predominant 11q23 chromosome translocation in infant ALL and is associated with an extremely poor prognosis. Our findings further suggest that fusion of MLL to one of the AF4 family members (AF4/LAF4/AF5Q31) might determine a proB‐cell phenotype in infant leukemia. © 2002 Wiley‐Liss, Inc.
DEAF‐1 function is essential for the early embryonic development of drosophila
Authors: Veraksa Alexey , Kennison James , McGinnis William
Published: October 2002

Summary: The Drosophila protein DEAF‐1 is a sequence‐specific DNA binding protein that was isolated as a putative cofactor of the Hox protein Deformed (Dfd). In this study, we analyze the effects of loss or gain of DEAF‐1 function on Drosophila development. Maternal/zygotic mutations of DEAF‐1 largely result in early embryonic arrest prior to the expression of zygotic segmentation genes, although a few embryos develop into larvae with segmentation defects of variable severity. Overexpression of DEAF‐1 protein in embryos can induce defects in migration/closure of the dorsal epidermis, and overexpression in adult primordia can strongly disrupt the development of eye or wing. The DEAF‐1 protein associates with many discrete sites on polytene chromosomes, suggesting that DEAF‐1 is a rather general regulator of gene expression. genesis 33:67–76, 2002. © 2002 Wiley‐Liss, Inc.
Geochemistry, mineralogy and petrogenesis of the northeast Niğde volcanics, central Anatolia, Turkey
Authors: Yurtmen Sema , Rowbotham George
Published: October 2002

The volcanics exposed in the northeast Niğde area are characterized by pumiceous pyroclastic rocks present as ash flows and fall deposits and by compositions ranging from dacite to rhyolite. Xenoliths found in the volcanics are basaltic andesite, andesite and dacite in composition. These rocks exhibit linear chemical variations between end‐member compositions and a continuity of trace element behaviour exists through the basaltic andesite–andesite–dacite–rhyolite compositional range. This is consistent with the fractionation of ferromagnesian minerals and plagioclase from a basaltic andesite or andesite parent. These rocks are peraluminous and show typical high‐K calc‐alkaline differentiation trends with total iron content decreasing progressively with increasing silica content. Bulk rock and mineral compositional trends and petrographic data suggest that crustal material was added to the magmas by subducted oceanic crust and is a likely contaminant of the source zone of the Niğde magmas.

The chemical variations in these volcanics indicate that crystal liquid fractionation has been a dominant process in controlling the chemistry of the northeast Niğde volcanics. It is also clear, from the petrographic and chemical features, that magma mixing with disequilibrium played a significant role in the evolution of the Niğde volcanic rocks. This is shown by normal and reverse zoning in plagioclase and resorption of most of the observed minerals. The xenoliths found in the Niğde volcanics represent the deeper part of the magma reservoir which equilibrated at the higher pressures. Copyright © 2002 John Wiley & Sons, Ltd.
Distinguishing depression from dementia in later life: a pilot study employing the Emotional Stroop task
Authors: Dudley Robert , O'Brien John , Barnett Nichola , McGuckin Liz , Britton Peter
Published: October 2002

Objectives

In later life, cognitive impairment is common in depression often making it difficult to distinguish a dementing illness from depression. We examined whether people with depression could be differentiated from those with dementia on their performance on a task that examines attentional bias to depression related material.

Methods

Twelve older adults who fulfilled DSM‐IV criteria for major depression were compared with 12 people with Alzheimer's Disease (AD) and 12 age matched controls on a test of cognitive biases: the Emotional Stroop task. In this task participants were presented with words written in different coloured inks, and they had to name the colour the word was written in. Four types of material were presented—neutral, positive, and negative emotion words as well as a condition of meaningless symbols.

Results

People with depression and those with AD were both slower than the controls on the task generally. However, the depressed group alone showed a statistically significant and specific increase in response time when colour naming the negative emotion words. The other two groups did not demonstrate such a pattern and colour named neutral, positive and negative words equally quickly.

Conclusions

The biased processing of depression related material may have a valuable role in distinguishing depression from dementia in later life. Although the Emotional Stroop in its present form is not sufficient for such a purpose. Furthermore, the demonstration that older adults with depression exhibit such biases helps provide a theoretical basis for the application of cognitive behavioural treatments with older adults. Copyright © 2002 John Wiley & Sons, Ltd.