bluuebunny/crossref_metadata_2025 huggingface dataset:
Connexin43 gap junction protein plays an essential role in morphogenesis of the embryonic chick face
Authors: McGonnell Imelda M. , Green Colin R. , Tickle Cheryll , Becker David L.
Published: August 2002

Normal outgrowth and fusion of facial primordia during vertebrate development require interaction of diverse tissues and co‐ordination of many different signalling pathways. Gap junction channels, made up of subunits consisting of connexin proteins, facilitate communication between cells and are implicated in embryonic development. Here we describe the distribution of connexin43 and connexin32 gap junction proteins in the developing chick face. To test the function of connexin43 protein, we applied antisense oligodeoxynucleotides that specifically reduced levels of connexin43 protein in cells of early chick facial primordia. This resulted in stunting of primordia outgrowth and led to facial defects. Furthermore, cell proliferation in regions of facial primordia that normally express high levels of connexin43 protein was reduced and this was associated with lower levels of Msx‐1 expression. Facial defects arise when retinoic acid is applied to the face of chick embryos at later stages. This treatment also resulted in significant reduction in connexin43 protein, while connexin32 protein expression was unaffected. Taken together, these results indicate that connexin43 plays an essential role during early morphogenesis and subsequent outgrowth of the developing chick face. © 2001 Wiley‐Liss, Inc.
A study on arrangement method of star couplers for passive double star systems
Authors: Tamaki Norio , Miki Noriki , Hashimoto Masashi , Kinoshita Takeshi , Watanabe Ryuichi
Published: August 2002

For economical construction of access networks, the passive double star (PDS) transmission system using optical fiber is promising. In the PDS transmission system, multiplexing of different transmission systems is possible due to wavelength division multiplexing (WDM). This system has drawn attention because addition of new service is easily accomplished. In this paper, an approach is proposed that is effective for wavelength division multiplexing in PDS transmission systems. When several systems with different transmit/receive level differences are transmitted over one fiber by wavelength division multiplexing, the transmission line length and the number must be adjusted to the system in which the transmit/receive level difference is the smallest in the conventional method. Hence, the application range of the system is degraded. On the other hand, in this paper, a method is proposed in which the loss distributions can be independently designed by cascading several star couplers when each system is wavelength division multiplexed. The method's procedure, evaluation of the efficiency of the accommodations, and an experimental example of an actual system are presented. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 84(7): 66–73, 2001
Rate‐adaptive indoor infrared wireless communication systems using punctured convolutional codes and adaptive PPM
Authors: Matsuo Michihito , Ohtsuki Tomoaki , Sasase Iwao , Udagawa Tomoyuki
Published: August 2002

In this paper, we propose rate‐adaptive indoor infrared wireless communication systems using punctured convolutional codes and adaptive pulse‐position modulation (PPM) to achieve high bit rates under various channel conditions with reasonable transmitter power. The proposed system varies the code rate of the rate compatible punctured convolutional (RCPC) codes and the modulation order of PPM adaptively according to the channel condition. When the channel condition is good, low‐order PPM and suitable code rates are selected, while high‐order PPM and suitable code rates are selected when the channel condition is bad. We analyze the performance of the proposed system on hybrid line‐of‐sight (LOS) channels. Our results show that the proposed system can achieve high bit rates by varying the code rate of the RCPC codes and the modulation order of PPM adaptively according to the channel conditions. Moreover, our results show that the proposed system can achieve longer horizontal separation between the transmitter and the receiver than that of conventional systems with repetition codes. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 84(8): 31–39, 2001
Resonant dc/dc converter with class DE tuned power oscillator
Authors: Matsuo Mitsuhiro , Suetsugu Tadashi , Mori Shinsaku , Sasase Iwao
Published: August 2002

In this paper, we propose a new resonant dc/dc converter with a class DE tuned power oscillator and a center‐tapped rectifier. The proposed converter uses a class DE tuned power oscillator as a dc/ac inverter. The MOSFET is used as a switch, which does not require any external drive circuits. Thus, compared to conventional inverters, the proposed circuits is effective in downsizing. Since the proposed circuit satisfies the class E switching operating condition, that is, the switching turns on and off instantaneously at zero voltage and zero slope of the voltage, highly efficient operation is possible at high frequencies. The proposed circuit is analyzed theoretically and is verified experimentally. The measured maximum dc/dc conversion efficiency is 75.8% at 2 MHz and 2.5 W. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 84(12): 61–69, 2001
Suppressing undesired modes in a higher‐order mode microstrip ring patch antenna
Authors: Tanaka Masato , Takahashi Norio
Published: August 2002

The authors propose the principles for a higher‐order mode ring patch antenna with a conical pattern with good symmetry for suppressing undesired modes and a simple configuration for creating such an antenna. In addition, the authors propose loading a degenerate separation element as a means to implement circular polarization in a higher‐ order mode ring patch antenna of this configuration and then confirm the circular polarization through experiments. The antenna has a simple configuration in which a microstrip line is positioned inside the ring and power is fed from the rear at the central point. The antenna offers the following advantages: line length to the edge of the power supply point and the ring patch that is roughly λ/4; and impedance at the power supply point that can be readily matched. Moreover, because the power supply point is at the central point of the ring patch antenna, this configuration is also beneficial in that it can be easily used for an array antenna by using it as an element of an array antenna that needs to be rotated and positioned, such as a sequential array antenna or a radial array antenna. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 85(3): 9–18, 2002
Application of Multirate Filter Bank to Group Demodulation of Frequency‐Multiplexed TDMA Signals
Authors: Matsuda Takahiro , Hara Shinsuke , Morinaga Norihiko
Published: August 2002

As a method to obtain the baseband signal from each of several time division multiple access (TDMA) signals that are frequency‐multiplexed in the uplink in wireless communication, this paper proposes a method of group demodulation using a multirate filter bank. The proposed method allows demodulation when the TDMA signals are asynchronously received in the uplink. Further, it can be applied to the case in which TDMA signals with different bandwidths are frequency‐multiplexed, if the multiple resolution capability of the multirate filter bank is used. Hence, this method is useful in the situation where several different types of signals coexist in such environments as software radio. In the systems discussed in this paper, it is necessary to realize a sharp amplitude response and a linear phase response in the filters of the multirate filter bank with a small computational effort. This is accomplished in this paper by using an infinite impulse response (IIR) filter with approximately linear phase response. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 85(4): 44–52, 2002
Slot array antenna for wireless LANs with backward excitation
Authors: Yamamoto Manabu , Ishizaki Kosuke , Muramoto Mitsuru , Sasaki Kanemi , Itoh Kiyohiko
Published: August 2002

Attention is directed to the slot array antenna that is serially fed by a microstrip line and a method is studied for using this antenna as a constituent element of a planar multisector antenna for wireless LAN. Based on the design ignoring the mutual coupling between the slots, an excitation method for realization of a beam tilt toward the endfire direction is investigated. It is found that backward excitation is effective. The antenna is modeled by the spectral domain moment method and a design is carried out by taking into account the mutual coupling. Further, by test measurement, the validity of the modeling and the effectiveness of the proposed design method are confirmed. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(9): 59–68, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1126
Target tracking with adaptive sampling intervals using a phased array radar
Authors: Yanbe Akio , Ito Masayoshi , Tsujimichi Shingo , Kosuge Yoshio
Published: August 2002

The phased array antenna can instantaneously direct a radar beam into a desired direction without mechanically moving the antenna. Anticipating an application to a phased array radar, adaptive control of the sampling interval for the tracking object is considered. Reducing the sampling interval for a target with high maneuverability prevents degradation of the tracking accuracy. For a target in straight‐line motion, the sampling interval is increased so that the number of observations is reduced for an efficient operation of radar resources. In this paper, the M3(Multiple Maneuver Model) filter is used as one of the tracking algorithms based on the multiple motion model, and a control scheme is proposed with a sampling interval based on the tracking error covariance matrix. By means of simulation, the tracking performance is compared with the case where the sampling interval is fixed. As a result, the tracking accuracy is improved by 15% during a maneuvering motion without increasing radar resources. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(10): 44–54, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1130
An efficient method to search for the location of network services with multiple QoSs guarantee
Authors: Kawano Keita , Masuda Tomokazu , Kinoshita Kazuhiko , Murakami Koso
Published: August 2002

For future multimedia communication networks, it is an essential element to guarantee multiple QoSs so that users have satisfactory services. Thus, recently, many QoS routing algorithms have been proposed. However, they merely select a point‐to‐point path which has sufficient resources for the request for QoSs. Therefore, it is difficult to search for the location of the service which is provided according to their request and to select a feasible path from the service provider to the originating node by QoS routing alone. Furthermore, for multimedia communications, there are many service providers which provide the same service content, and each of them attaches individual QoS values to their service content. There are, however, few studies of methods to search for the location of services which are provided with these QoSs. Therefore, in this paper, a new method to search for the location of services with multiple QoS guarantee is proposed. It allows fast searching by utilizing the link state. Finally, we show by simulation experiments that the proposed method has good performance. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(10): 55–63, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1131
Distinctive features of thin‐layer sealed lead‐acid storage batteries with comb‐shaped plates
Authors: Horie Toshio , Takahashi Minoru , Ogata Tsutomu , Hirai Toshiro
Published: August 2002

We fabricated 2.5‐mm thick lead‐acid cells with comb‐shaped electrodes, sealed with laminated sheets, and estimated their performance. Some of the cells showed above 500 mAh of an initial capacity and one of them were cycled over 140 times till the capacity decreased to a half of the initial capacity. The initial capacity was affected strongly by viscosity of electrolyte gel filled in the cells. Utilization of electrode active materials and electrolyte was more than 20% and 55%, respectively, in the cells showed above 500 mAh of initial capacity. Cycle life was influenced mainly by cathode degradation and electrolyte drying out. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(11): 60–67, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1138
Acquiring the ability of object localization by vision and audition through motion
Authors: Asai Yasuyuki , Nakashima Hiromichi , Yamamura Tsuyoshi , Huang Jie , Ohnishi Noboru
Published: August 2002

This paper proposes a sound source localization learning model based on iterated perception by vision and audition through neck rotation. Learning is performed through object localization by vision and audition with motion. The model is composed of three multilayered perceptron‐type neural networks. The error signal to be used in the learning by error backpropagation is acquired by motion. The learning process is as follows. For each generation of sound, four actions are performed: auditory localization, visual localization, search, and step centering. The learning is based on the acquired information. In order to verify the validity of the proposed model, a computer simulation experiment and an experiment using a robot and a real sound source were performed. The experiments demonstrated that auditory and visual localization are performed simultaneously. Generalization of the unlearned direction and efficient operation are also demonstrated. The localization error is examined as a function of the distance between the source and the robot. The mapping by the neural network after learning is also investigated. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(4): 58–67, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10046
Investigation of new‐mode‐type SAWs by procedures combined with finite‐element and analytical method, and their applications for devices used in mobile communications
Authors: Isobe Atsushi , Hikita Mitsutaka , Asai Kengo , Sumioka Atsushi
Published: August 2002

Simulations using a combination of the finite‐element method and the analytical method as well as experiments are used to study new‐mode‐type SAWs. First, in 171°YZé‐LiNbO3, it is found that there exists a longitudinal leaky SAW with a high acoustic velocity and a high Q in a grating structure with an Al film thickness of 0.084 wavelength. The acoustic velocity is 6100 to 6500 m/s and the Q values are more than 4000 (computed) at both the resonance and antiresonance points. These excellent properties are suitable for high‐frequency SAW devices. Next, in 15°YX‐LiNbO3, it is found that there exists a grating mode SAW of a transverse wave type in a grating structure with an Al film thickness of 0.125 wavelength. In this case,k2has an extremely large value of 28.5% and hence the mode is suitable for a SAW resonator for use in a voltage‐controlled oscillator. By means of this SAW, SAW‐VCOs at 400 and 170 MHz for mobile communication are fabricated. At 400 MHz, the frequency variable width is 54 MHz (3.2%/V) and the phase noise is less than –115 dBc/Hz at 25 kHz; the corresponding values at 170 MHz are 24 MHz (3.4%/V) and < –12 dBc/Hz at 25 kHz. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(4): 49–58, 2001
Design of low‐delay perfect‐reconstruction filter banks using linear programming
Authors: Ota Morihiko , Higa Yoshito , Ochii Hiroshi
Published: August 2002

In many applications of filter banks, a low‐delay filter bank in which the system delay is small is desirable. In this paper, two new design methods are proposed for low‐delay perfect‐reconstruction filter banks. First, a design method is described for a two‐channel perfect‐reconstruction filter bank suitable for subband coding. In this method, a high‐pass filter for perfect reconstruction is designed for an arbitrary low‐pass filter. Next, a design method is described for an oversampling perfect‐reconstruction DFT filter bank suitable for subband adaptive filter. In this method, a prototype filter for a perfect‐reconstruction synthesizer is designed for the prototype filter for an arbitrary analyzer. The effectiveness of the present method is demonstrated by design examples. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(6): 30–39, 2001
Production of transparent conductive films with inserted SiO2anchor layer, and application to a resistive touch panel
Authors: Noda Kazuhiro , Tanimura Kohtaro
Published: August 2002

In order to reduce light reflectivity and enhance the durability of resistive touch panels used for pen input, a transparent conductive film consisting of an inserted SiO2anchor layer between PET and ITO layers (ITO/SiO2/PET) was produced and its application to resistive touch panels was attempted.

The luminous reflectance of the ITO/SiO2/PET structure was found to be about 4% lower than that of ITO/PET. The durability was estimated by the resistance change ratio of the ITO layer caused by damage due to scribbling; the decrease in resistance of the ITO/SiO2/PET structure was less than half that of the ITO/PET structure. Furthermore, the resistivity of the ITO layer in ITO/SiO2/PET was 8.4 × 10–4Ω‐cm, lower than the value of 1.3 × 10–3Ω‐cm in ITO/PET. This demonstrates the conductivity‐increasing effect of the insertion of a SiO2layer into the transparent conductive film. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(7): 39–45, 2001
Plane‐Type Fiberoptic Switches
Authors: Horino Masaya , Sato Kazutaka , Hayashi Yukio , Mita Masahiro , Nishiyama Toshikazu
Published: August 2002

The optical switch is an essential and indispensable optical device in improving reliability and developing advanced functions in optical communications systems and occupies an extremely important position in the development of optical communications technology. With the objective of developing a mechanical optical switch having a compact, low‐loss, simple assembly, new optical switches that mechanically move the optical fibers have been devised and subjected to various investigations. In this paper, we describe the operating principle and the assembly process of an optical switch and examine its basic characteristics as an optical switch by using a prototype. From the results, we found that the latching can be switched by using an electromagnetic actuator that combines a permanent magnet and coils. In addition, an insertion loss below 1 dB and a return loss of nearly 50 dB were obtained. Furthermore, a continuous switching test was performed and optical switching was possible after 10,000,000 operations. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 85(1): 41–49, 2002
Transient analysis of lossy nonuniform transmission line using the finite difference time domain method
Authors: Sekine Toshikazu , Kobayashi Kunikatsu , Yokokawa Senji
Published: August 2002

With a view to carrying out a highly accurate and fast time domain analysis of a lossy nonuniform transmission line, a method is described for application of the FDTD method to a finitely long lossy nonuniform transmission line. The present method is applied to a parabolic transmission line as one variety of nonuniform transmission line and a step response analysis is performed. By comparison with an analytical solution and other methods, the effectiveness of the method is confirmed. Also, the step response at the output end of a lossy nonuniform transmission line is almost a step waveform under conditions different from the distortionless transmission condition of a uniform line. Based on this result, a method is described for approximating the step response waveform at the output end of a lossy parabolic line to a step waveform. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 85(8): 1–10, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10006
Blind deconvolution of blurred images by use of ICA
Authors: Umeyama Shinji
Published: August 2002

Independent Component Analysis is a new data analysis method, and its computation algorithms and applications have been widely studied recently. Most applications, however, are in the field of one‐dimensional data analysis, such as sound data analysis, and few applications for two‐dimensional data (e.g., image data) have been studied. In this paper, a new application of ICA for two‐dimensional data analysis is given, namely, image restoration of blurred images. The proposed method can restore the original image without knowing the blurring process. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 84(12): 1–9, 2001
Packing of L‐shaped and rectangular modules using sequence‐pair method
Authors: Fujiyoshi Kunihiro , Murata Hiroshi
Published: August 2002

Rectangle packing is a critical problem in applications such as placement in VLSI layouts. Recently, the sequence‐pair method was proposed as a representation method for rectangle packing where the general configuration is not restricted to the slice configuration. This method has led to a variety of research on applications because of its feature of packing all sequence‐pairs in addition to the ability to represent any kind of packing. In this paper, we propose a method that uses the sequence‐pair to represent packing L‐shaped modules and not only rectangular modules. Then we propose an algorithm to obtain the total number of modules,n, inO(n3) time in the densest packing in “packing that restored all of the L‐shaped modules while obeying the horizontal and vertical constraints imposed by the given sequence‐pair.” Furthermore, the necessary and sufficient conditions for packing the given sequence‐pair and the proofs are given. These necessary and sufficient conditions are not related to the module size and depend only on the sequence‐pair. Finally, the effectiveness of the proposed algorithm is demonstrated from test results. © 2001 Scripta Technica, Electron Comm Jpn Pt 3, 85(2): 52–64, 2002
Influence of surface roughness on the charging of insulating spacers in vacuum
Authors: Yamamoto Osamu , Takuma Tadasu , Hamada Shoji , Kakehashi Yasuhiro , Ikoma Shingo , Nishimura Kouichi , Shioiri Tetsu
Published: August 2002

This paper describes the charging phenomena of cylindrical insulators made of PMMA, PTFE, or Al2O3under ramped and stepped dc voltage. It is primarily concerned with the influence of surface roughness on the formation of charging for various insulating spacers. By using an electrostatic probe located on the cathode, we conducted real‐time observations of the electric field induced by the surface charge. It was found that the surface roughness positively affects the charging, which becomes more pronounced in insulators polished to a higher degree. Furthermore, polished insulators are characterized by a shorter time lag. These results show the importance of surface treatment for insulating spacers in vacuum. © 2001 Scripta Technica, Electr Eng Jpn, 135(3): 16–25, 2001
Fluctuation analysis of partial discharge pulse occurrence with an integral equation
Authors: Okamoto Tatsuki , Kato Takeyoshi , Yokomizu Yasunobu , Suzuoki Yasuo
Published: August 2002

This paper proposes an integral equation to describe the stochastic fluctuation of partial discharge (PD) occurrence under sinusoidal voltage stress based on a simple PD model. In the model, the stochastic behavior of PD fluctuation is assumed to arise from the fluctuation of the PD delay time after the inception voltage is built up across a discharge gap. For simplicity of calculation, the delay time is assumed to have an exponential distribution. Based on these assumptions, it is found that the proposed integral equation provides the basic characteristics such as the PD pulse distribution in the applied voltage phase angle domain. The authors have solved the equation numerically and demonstrate several ϕ–ndistribution patterns with average delay times of 0.05 to 5 ms at low applied voltage. The solution is compared with PD characteristics obtained by Monte Carlo simulation based on the same PD model, and good agreement is found. © 2001 Scripta Technica, Electr Eng Jpn, 136(1): 16–28, 2001
Some suggestions for regional industrial ecosystems – extended industrial ecology
Authors: Korhonen Jouni
Published: August 2002

Industrial ecology (IE) is an emerging concept from industrial environmental management arising from a provocative ecosystem analogy of recycling orroundputsystems. The systems approach in the concept, i.e. to facilitate the emergence of entire industrial systems based on cooperation in waste material and energy utilization between the actors involved in the system, has been applied in only a few case studies. These have been conducted with regional industrial systems. In this paper the ecosystem analogy in IE is extended to include also the three other basic principles or metaphors of system development of ecosystems besides roundput: diversity, locality and gradual change. The four ecosystem metaphors constitute theextended industrial ecologyapproach, in which the metaphors are considered in industrial systems. An example of a regional industrial ecology study with the Jyväskylä industrial ecosystem is considered with the thesis. Some initial suggestions for developing the extended industrial ecology approach are presented. Copyright © 2001 John Wiley & Sons, Ltd. and ERP Environment
One size doesn't fit all: estimating environmental Kuznets curves for hazardous waste site counts
Authors: Bohara Alok K. , Berrens Robert P. , Gawande Kishore , Wang Pingo
Published: August 2002

An emergent empirical literature demonstrates theenvironmental Kuznets curve(EKC), or inverted‐U relationship, between environmental pollution and per capita income. Results are controversial and open to a variety of interpretations. The first contribution of this paper is to extend the limited empirical evidence of the EKC relationship to an unexpected context – counts of hazardous waste sites across U.S. counties. However, the primary contribution of this paper is methodological. By applying the EM algorithm, and the latent class Poisson model, to heterogeneous count data we employ an innovative technique for investigating EKC results. This approach allows us to identify three latent classes all exhibiting the inverted‐U relationship but with distinct characteristics. Hence one size doesn't fit all, and we find that three EKCs are required to adequately fit the data. One potential implication is that environmental policy should be designed differentially for these different classes. In particular, it may need to be geographically targeted for the efficient cleanup of blighted urban areas. Finally, future EKC studies should evaluate the potential for multiple curves. Copyright © 2001 John Wiley & Sons, Ltd.
Use of Bayesian dynamic models for updating estimates of contaminated material
Authors: Gargoum A. S.
Published: August 2002

Experienced personnel and safety engineers have a great deal of expertise about the profile of the future emission of contaminated mass from the source after an accident (nuclear, chemical, …). This expert judgement, some quantitative and some qualitative, would be available from the time of the initial release (prior information) and can be accommodated into Bayesian uncertainty management in dispersal models such as puff models. To make full use of this expertise, we outline how prior qualitative information about the expected development of the emission can be modeled as a dynamic linear model (DLM). This prediction model will be used to provide estimates of the source term along with associated uncertainties. Details of matching expert judgement and expected emission profiles are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Performance of partial Mann–Kendall tests for trend detection in the presence of covariates
Authors: Libiseller Claudia , Grimvall Anders
Published: August 2002

Trend analyses of time series of environmental data are often carried out to assess the human impact on the environment under the influence of natural fluctuations in temperature, precipitation, and other factors that may affect the studied response variable. We examine the performance of partial Mann–Kendall (PMK) tests, i.e. trend tests in which the critical region is determined by the conditional distribution of one Mann‐Kendall (MK) statistic for monotone trend, given a set of other MK statistics. In particular, we examine the impact of incorporating information regarding covariates in the Hirsch–Slack test for trends in serially correlated data collected over several seasons. Monte Carlo simulation of the performance of PMK tests demonstrates that the gain in power due to incorporation of relevant covariates can be large compared to the loss in power caused by irrelevant covariates. Furthermore, we have found that the asymptotic normality of the test statistics in such tests enables rapid and reliable determination of critical regions, unless the sample size is very small (n < 10) or the different MK statistics are very strongly correlated. A case study of water quality trends shows that PMK tests can detect and correct for rather complex relationships between river water quality and water discharge. The generic character of the PMK tests makes them particularly useful for scanning large sets of data for temporal trends. Copyright © 2002 John Wiley & Sons, Ltd.
Non‐parametric confidence intervals for correlations in nearest‐neighbour Markov point processes
Authors: Pallini Andrea
Published: August 2002

We study bootstrap confidence intervals for correlation functions in nearest‐neighbour Markov point processes, where the neighbours are characterized by an interaction of bounded radiusr. In forestry statistics, the points are tree locations belonging to a region (forest) A, and the marks are qualitative or quantitative tree variables, such as tree species, the stem diameter, crown length or tree height. Estimating and analysing correlation functions between locations and marks, cross‐correlations between different species and their marks, is typically a key step in statistical interpretation of mapped data sets from a forest stand. In order to define the original sample, we propose coding schemes, which are fixed and divide the observed region A of the point process into regular, conditionally independent subregions {Bυ} located at Euclidean distanced ≥ 2r. Bootstrap confidence intervals are then obtained directly, by considering kernel density estimates from all subregions {Bυ} as conditionally independent replicates. Copyright © 2002 John Wiley & Sons, Ltd.
The extent of soil erosion in upland England and Wales
Authors: McHugh Marianne , Harrod Tim , Morgan Roy
Published: August 2002

Following recommendations by the 19th Royal Commission on Environmental Pollution, the area, causes and rates of upland soil erosion in England and Wales were investigated between 1997 and 1999. This paper describes the methods and results of the field survey of 1999 in which the extent of eroded ground was determined. 2. The area of degraded soil and the volume of eroded material were both determined from the dimensions of individual erosion features at 399 field sites located on an orthogonal grid across the uplands. Using measurements of individual erosion features, degraded soil extent in upland England and Wales was estimated at almost 25 000 ha, 2·46 per cent of the total upland area surveyed. Half this eroded area was revegetated and no longer subject to continued accelerated soil loss in 1999. The total volume of eroded material was estimated at 0·284 km3. Although deposition of eroded material occurred within 20 per cent of eroded field sites, the total volume of redeposited material was less than 1 per cent of the total volume of eroded soil. 3. Erosion was more extensive on peat soils than on dry, wet mineral or wet peaty mineral soils. In addition, the higher incidence of erosion at high altitudes and on low slopes reinforced the relationship between erosion and areas of peat formation. Copyright © 2002 John Wiley & Sons, Ltd.
Essential oil of Lantana camara L. occurring in Iran
Authors: Sefidkon Fatemeh
Published: August 2002

Hydro‐ and steam‐distilled volatile oils from the leaves and flowers of Lantana camara L. were analysed by a combination of GC and GC–MS. Forty‐four components in the hydrodistilled oil and 25 components in the steam‐distilled oil were identified. The main constituents characterized were sabinene (16.5% and 7.3%), β‐caryophyllene (14.0% and 22.5%), 1,8‐cineole (10.0% and 6.0%), bicyclogermacrene (8.1% and 18.4%) and α‐humulene (6.0% and 10.8%) in the hydro‐ and steam‐distilled oils, respectively. Copyright © 2001 John Wiley & Sons, Ltd.
Analysis of hybrid algorithms for the Navier–Stokes equations with respect to hydrodynamic stability theory
Authors: Passoni Giuseppe , Alfonsi Giancarlo , Galbiati Massimo
Published: August 2002

Hybrid three‐dimensional algorithms for the numerical integration of the incompressible Navier–Stokes equations are analyzed with respect to hydrodynamic stability in both linear and nonlinear fields. The computational schemes are mixed—spectral and finite differences—and are applied to the case of the channel flow driven by constant pressure gradient; time marching is handled with the fractional step method. Different formulations—fully explicit convective term, partially and fully implicit viscous term combined with uniform, stretched, staggered and non‐staggered meshes, x‐velocity splitted and non‐splitted in average and perturbation component – are analyzed by monitoring the evolution in time of both small and finite amplitude perturbations of the mean flow. The results in the linear field are compared with correspondent solutions of the Orr–Sommerfeld equation; in the nonlinear field, the comparison is made with results obtained by other authors. Copyright © 2002 John Wiley & Sons, Ltd.
Simulating three‐dimensional aeronautical flows on mixed block‐structured/semi‐structured/unstructured meshes
Authors: Shaw J. A. , Peace A. J.
Published: August 2002

The design requirements of a computational fluid dynamics (CFD) method for modelling high Reynolds number flows over complete aircraft are reviewed. It is found that the specifications are unlikely to be met by an approach based on the sole use of either structured or unstructured grids. Instead, it is proposed that a hybrid combination of these grids is appropriate. Techniques for developing such meshes are given and the process of establishing the data structure defining the meshes described. Details of a flow algorithm which operates on a hybrid mesh are presented. A description is given of the suitability and generation of hybrid grids for a number of examples, and results from flow simulations shown. Finally, issues still to be addressed in the practical use of these meshes are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Identifying the Factors that Affect Interest‐Rate Swap Spreads: Some Evidence from the United States and the United Kingdom
Authors: Lekkos Ilias , Milas Costas
Published: August 2002

We assess the ability of the factors proposed in previous research to account for the stochastic evolution of the term structure of the U.S. and U.K. swap spreads. Using as factor proxies the level, volatility, and slope of the zero‐coupon government yield curve as well as the Treasury‐bill—London Interbank Offer Rate (LIBOR) spread and the corporate bond spread, we identify a procyclical behavior for the short‐maturity U.S. swap spreads and a countercyclical behavior for longer maturity U.S. swap spreads. Liquidity and corporate bond spreads are also significant, but their importance varies with maturity. The liquidity premium is more important for short‐maturity swap spreads, although the corporate bond spread affects long‐maturity swap spreads. For the United Kingdom, swap spreads are countercyclical across maturities. In addition, we find that shocks to the liquidity premium are more significant for long‐maturity swaps and that the links between corporate bond markets and swap markets are much stronger than in the United States. When we look at the links between U.S. and U.K. swap markets, we identify a significant influence of the U.S. factors on the U.K. swap spreads across maturities. © 2001 John Wiley & Sons, Inc. Jrl Fut Mark 21:737–768, 2001
Combined copy status of 18q21 genes in colorectal cancer shows frequent retention of SMAD7
Authors: Boulay Jean‐Louis , Mild Gabriele , Reuter Juergen , Lagrange Magali , Terracciano Luigi , Lowy Adam , Laffer Urban , Orth Bernd , Metzger Urs , Stamm Bernhard , Martinoli Sebastiano , Herrmann Richard , Rochlitz Christoph
Published: August 2002

Deletions of chromosome band 18q21 appear with very high frequency in a variety of carcinomas, especially in colorectal cancer. Potent tumor suppressor genes located in this region encode transforming growth factor β (TGF‐β) signal transducers SMAD2 and SMAD4, and inactivation of either one leads to impaired TGF‐β‐mediated cell growth/apoptosis. Following the assignment of SMAD7 to 18q21, we first refined the SMAD7 gene position within this region by genetically mapping SMAD7 between SMAD2 and SMAD4. Further, to compare the respective frequencies of genetic alterations of these three SMAD genes in colorectal cancer, we undertook a large‐scale evaluation of the copy status of each of these genes on DNA samples from colorectal tumor biopsy material. Among a subset of 233 DNA samples for which data were available for all four genes, SMAD4, SMAD2, and the nearby gene DCC showed high deletion rates (66%, 64%, and 59%, respectively), whereas SMAD7 was deleted in only 48% of the tumors. Unexpectedly, we found some gene duplications; SMAD7 appears to be more frequently amplified (10%) than the three other genes (4–7%). Compiled data for SMAD genes in each tumor show that the most common combination (26% of all the tumors) consists of the simultaneous deletions of SMAD2 and SMAD4 associated with normal diploidy or even duplication of SMAD7. Since SMAD7 normally counteracts SMAD2 and SMAD4 in TGF‐β signaling, we hypothesize that the tumor might not benefit from simultaneous SMAD7 inactivation, thereby exerting selective pressure to retain or even to duplicate the SMAD7 gene. © 2001 Wiley‐Liss, Inc.
Novel cryptic, complex rearrangements involving ETV6‐CBFA2 (TEL‐AML1) genes identified by fluorescence in situ hybridization in pediatric patients with acute lymphoblastic leukemia
Authors: Mathew Susan , Shurtleff Sheila A. , Raimondi Susana C.
Published: August 2002

In childhood B‐lineage acute lymphoblastic leukemia (ALL), the most common genetic change, the ETV6‐CBFA2 (TEL‐AML1) fusion resulting from the cryptic t(12;21)(p13;q22) is associated with a favorable outcome. Therefore, it is important to identify patients with this translocation so that they can receive appropriate treatment. To identify new partner breakpoints for ETV6 and CBFA2, we selected 30 patients with childhood ALL in whose leukemic cells a t(12;21) had been detected by RT‐PCR. Conventional cytogenetics revealed that 12p abnormalities were present in 10 patients and that other random abnormalities were present in another 15, including 9 with a numerical or structural abnormality of chromosome 21. Normal karyotypes were observed in the leukemic blasts of five patients. Interphase fluorescence in situ hybridization (FISH) confirmed the RT‐PCR finding of the t(12;21) in each patient and detected the loss of the wild‐type ETV6 allele in 14 (47%) patients. Metaphase cells from only 20 patients were available for additional FISH analysis. In 13 patients, the expected fusion signal of t(12;21) was observed on der(21)t(12;21), and the reciprocal CBFA2 signal was observed on der(12)t(12;21). However, in six patients with the ETV6‐CBFA2 fusion on chromosome 21, the reciprocal CBFA2 signal was observed not on 12p13 but on 4q21, 4q27, 8q24, 11q24, 14q11.2, or 16p13.1. In four of these six patients, we found interstitial insertions of part of CBFA2. In another patient, the ETV6‐CBFA2 fusion was observed on 4q21 rather than on 21q. Thus, seven (35%) of the 20 patients with a t(12;21) revealed complex rearrangements. Our findings also indicate the importance of analyzing metaphase chromosomes in identifying cryptic and complex rearrangements involving ETV6 and CBFA2. © 2001 Wiley‐Liss, Inc.
Truncated product method for combiningP‐values
Authors: Zaykin D.V. , Zhivotovsky Lev A. , Westfall P.H. , Weir B.S.
Published: August 2002

We present a new procedure for combiningP‐values from a set ofLhypothesis tests. Our procedure is to take the product of only thoseP‐values less than some specified cut‐off value and to evaluate the probability of such a product, or a smaller value, under the overall hypothesis that allLhypotheses are true. We give an explicit formulation for thisP‐value, and find by simulation that it can provide high power for detecting departures from the overall hypothesis. We extend the procedure to situations when tests are not independent. We present both real and simulated examples where the method is especially useful. These include exploratory analyses whenLis large, such as genome‐wide scans for marker‐trait associations and meta‐analytic applications that combine information from published studies, with potential for dealing with the “publication bias” phenomenon. Once the overall hypothesis is rejected, an adjustment procedure with strong family‐wise error protection is available for smaller subsets of hypotheses, down to the individual tests. Genet. Epidemiol. 22:170–185, 2002. © 2002 Wiley‐Liss, Inc.
Lagoon–tidal flat sedimentation in an epeiric sea: Proterozoic Bhander Group, Son Valley, India
Authors: Chakraborty Chandan
Published: August 2002

The Bhander Group, the uppermost stratigraphic unit of the Proterozoic Vindhyan Supergroup in Son Valley, exhibits in its upper part a 550 m thick, muddy siliciclastic succession characterized by features indicative of deposition in a wave‐affected coastal, lagoon–tidal flat environment suffering repeated submergence and emergence. The basic architecture of the deposit is alternation of centimetre‐ to decimetre‐thick sheet‐like interbeds of coarser clastics (mainly sandstone) and decimetre‐thick mudstones. The coarser interlayers are dominated by a variety of ripple‐formed laminations. The preserved ripple forms on bed‐top surfaces and their internal lamination style suggest both oscillatory and combined flows for their formation. Interference, superimposed, ladder‐back and flat‐topped ripples are also common. Synsedimentary cracks, wrinkle marks, features resembling rain prints and adhesion structures occur in profusion on bed‐top surfaces. Salt pseudomorphs are also present at the bases of beds. The mudstone intervals represent suspension settlement and show partings with interfaces characterized by synsedimentary cracks. It is inferred that the sediments were deposited on a coastal plain characterized by a peritidal (supratidal–intertidal) flat and evaporative lagoon suffering repeated submergence and emergence due to storm‐induced coastal setup and setdown in addition to tidal fluctuations.

The 550 m thick coastal flat succession is surprisingly devoid of any barrier bar deposits and also lacks shoreface and shelfal strata. The large areal extent of the coastal flat succession (c. 100,000 km2) and its great thickness indicate an extremely low‐gradient epeiric basin characterized by an extensive coastal flat sheltered from the deeper marine domain. It is inferred that the Bhander coastal flat was protected from the open sea by the Bundelkhand basement arch to the north of the Vindhyan basin, instead of barrier bars. Such a setting favoured accumulation of a high proportion of terrigenous mud in the coastal plain, in contrast to many described examples from the Proterozoic. Copyright © 2001 John Wiley & Sons, Ltd.
Microglial reaction induced by noncytotoxic methylmercury treatment leads to neuroprotection via interactions with astrocytes and IL‐6 release
Authors: Eskes Chantra , Honegger Paul , Juillerat‐Jeanneret Lucienne , Monnet‐Tschudi Florianne
Published: August 2002

Microglial cells react early to a neurotoxic insult. However, the bioactive factors and the cell‐cell interactions leading to microglial activation and finally to a neuroprotective or neurodegenerative outcome remain to be elucidated. Therefore, we analyzed the microglial reaction induced by methylmercury (MeHgCl) using cell cultures of different complexity. Isolated miroglia were found to be directly activated by MeHgCl (10−10 to 10−6 M), as indicated by process retraction, enhanced lectin staining, and cluster formation. An association of MeHgCl–induced microglial clusters with astrocytes and neurons was observed in three‐dimensional cultures. Close proximity was found between the clusters of lectin‐stained microglia and astrocytes immunostained for glial fibrillary acidic protein (GFAP), which may facilitate interactions between astrocytes and reactive microglia. In contrast, immunoreactivity for microtubule‐associated protein (MAP‐2), a neuronal marker, was absent in the vicinity of the microglial clusters. Interactions between astrocytes and microglia were studied in cocultures treated for 10 days with MeHgCl. Interleukin‐6 release was increased at 10−7 M of MeHgCl, whereas it was decreased when each of these two cell types was cultured separately. Moreover, addition of IL‐6 to three‐dimensional brain cell cultures treated with 3 × 10−7 M of MeHgCl prevented the decrease in immunostaining of the neuronal markers MAP‐2 and neurofilament‐M. IL‐6 administered to three‐dimensional cultures in the absence of MeHgCl caused astrogliosis, as indicated by increased GFAP immunoreactivity. Altogether, these results show that microglial cells are directly activated by MeHgCl and that the interaction between activated microglia and astrocytes can increase local IL‐6 release, which may cause astrocyte reactivity and neuroprotection. GLIA 37:43–52, 2002. © 2002 Wiley‐Liss, Inc.
Glial cells as targets for cytotoxic immune mediators
Authors: Benn Tracey , Halfpenny Christopher , Scolding Neil
Published: August 2002

Oligodendrocytes and Schwann cells are the glia principally responsible for the synthesis and maintenance of myelin. Damage may occur to these cells in a number of conditions, but perhaps the most studied are the idiopathic inflammatory demyelinating diseases, multiple sclerosis in the CNS, and Guillain‐Barré syndrome and its variants in the peripheral nervous system (PNS). This article explores the effects on these cells of cytotoxic immunological and inflammatory mediators: similarities are revealed, of which perhaps the most important is the sensitivity of both Schwann cells and oligodendrocytes to many such agents. This area of research is, however, characterised and complicated by numerous and often very substantial inter‐observer discrepancies. Marked variability in cell culture techniques, and in assays of cell damage and death, provide artifactual explanations for some of this variability; true inter‐species differences also contribute. Not the least important conclusion centres on the limited capacity of in vitro studies to reveal disease mechanisms: cell culture findings merely illustrate possibilities which must then be tested ex vivo using human tissue samples affected by the relevant disease. GLIA 36:200–211, 2001. © 2001 Wiley‐Liss, Inc.