bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental and theoretical simulations of seismic poundings between two adjacent structures
Authors: Chau K. T. , Wei X. X. , Guo X. , Shen C. Y.
Published: March 2003

Shaking table tests have been carried out to investigate the pounding phenomenon between two steel towers of different natural frequencies and damping ratios, subject to different combinations of stand‐off distance and seismic excitations. Both harmonic waves and ground motions of the 1940 El Centro earthquake are used as input. Subjected to sinusoidal excitations, poundings between the two towers could appear as either periodic or chaotic. For periodic poundings, impact normally occurs once within each excitation cycle or within every other excitation cycle. A type of periodic group poundings was also observed for the first time (i.e. a group of non‐periodic poundings repeating themselves periodically). Chaotic motions develop when the difference of the natural frequency of the two towers become larger. Under sinusoidal excitations, the maximum relative impact velocity always develops at an excitation frequency between the natural frequencies of the two towers. Both analytical and numerical predictions of the relative impact velocity, the maximum stand‐off distance, and the excitation frequency range for pounding occurrences were made and found to be comparable with the experimental observations in most of the cases. The stand‐off distance attains a maximum when the excitation frequency is close to that of the more flexible tower. Pounding appears to amplify the response of the stiffer structure but suppress that of the more flexible structure; and this agrees qualitatively with previous shaking table tests and theoretical studies. Copyright © 2003 John Wiley & Sons, Ltd.
Scattering of elastic waves by a general anisotropic basin. Part 2: a 3D model
Authors: Dravinski Marijan
Published: March 2003

Scattering of plane harmonic waves by a three‐dimensional basin of arbitrary shape embedded within elastic half‐space is investigated by using an indirect boundary integral equation approach. The materials of the basin and the half‐space are assumed to be the most general anisotropic, homogeneous, linearly elastic solids without any material symmetry (i.e. triclinic).

The unknown scattered waves are expressed in terms of three‐dimensional triclinic time harmonic full‐space Green's functions. The results have been tested by comparing the surface response of semi spherical isotropic and transversely isotropic basins for which the numerical solutions are available.

Surface displacements are presented for a semicircular basin subjected to a vertical incident plane harmonic pseudo‐P‐, SV‐, or SH‐wave. These results are compared with the motion obtained for the corresponding equivalent isotropic models. The results show that presence of the basin may cause significant amplification of ground motion when compared to the free‐field displacements. The peak amplitude of the predominant component of surface motion is smaller for the anisotropic basin than for the corresponding isotropic one. Anisotropic response may be asymmetric even for symmetric geometry and incidence. Anisotropic surface displacement generally includes all three components of motion which may not be the case for the isotropic results. Furthermore, anisotropic response strongly depends upon the nature of the incident wave, degree of material anisotropy and the azimuthal orientation of the observation station.

These results clearly demonstrate the importance of anisotropy in amplification of surface ground motion. Copyright © 2003 John Wiley & Sons, Ltd.
The effects of torsion and motion coupling in site response estimation
Authors: Ghayamghamian Mohammad R. , Motosaka Masato
Published: March 2003

Soil amplification characteristics are investigated using data from the Chibaken‐Toho‐Oki earthquake and its aftershocks recorded at Chiba dense array in Japan. The frequency‐dependent amplification function of soil is calculated using uphole‐to‐downhole spectral ratio analysis, considering the horizontal components of shear wave. The identified spectral ratios consistently demonstrate the splitting of peaks in their resonance frequencies and low amplification values in comparison with a 1D model. The torsional behaviour and horizontal ground motion coupling are clarified as the reasons for these phenomena at the site. To prove the hypothesis, the torsional motion is directly evaluated using the data of the horizontal dense array in different depths at the site. The comparison between Fourier spectra of torsional motion and identified transfer functions reveals the peaks at the same frequencies. The wave equation including torsion and horizontal motion coupling is introduced and solved for the layered media by applying wave propagation theory. Using the developed model, the effects of torsional motion with horizontal motion coupling on soil transfer function are numerically examined. Splitting and low amplification at resonance frequencies are confirmed by the results of numerical analysis. Furthermore, the ground motion in two horizontal directions at the site is simulated using site geotechnical specification and optimizing the model parameters. The simulated and recorded motions demonstrate good agreement that is used to validate the hypothesis. In addition, the spectral density of torsional ground motions are compared with the calculated one and found to be well predicted by the model. Finally, the results are used to explain the overestimation of damping in back‐calculation of dynamic soil properties using vertical array data in small strain level. Copyright © 2003 John Wiley & Sons, Ltd.
Optimum seismic zoning for multiple types of structures
Authors: García‐Pérez Jaime , Castellanos Francisco , Díaz Orlando
Published: March 2003

We consider zoning for the design criterion that minimizes the expected present value of the total cost, including the initial cost as well as losses due to damage and failure. The problem consists of the following: given the number of zones, their boundaries and design coefficients must be such that they minimize the expected present value of all structures built in the region. We will refer to solutions in one or more dimensions, depending on the number of the types of structures built in the region to be zoned. Two methods are proposed to solve the problems. The first method is based on the different combinations performed in order to attain optimum zoning. The second method uses an analogy to the evolution of biological systems. The work ends by applying the methods developed to a region of known seismicity. Copyright © 2003 John Wiley & Sons, Ltd.
Reliability‐based robust control for uncertain dynamical systems using feedback of incomplete noisy response measurements
Authors: Yuen Ka‐Veng , Beck James L.
Published: March 2003

A reliability‐based output feedback control methodology is presented for controlling the dynamic response of systems that are represented by linear state‐space models. The design criterion is based on a robust failure probability for the system. This criterion provides robustness for the controlled system by considering a probability distribution over a set of possible system models with a stochastic model of the excitation so that robust performance is expected. The control command signal can be calculated using incomplete response measurements at previous time steps without requiring state estimation. Examples of robust structural control using an active mass driver on a shear building model and on a benchmark structure are presented to illustrate the proposed method. Copyright © 2003 John Wiley & Sons, Ltd.
Identification of parametric ground motion random fields from spatially recorded seismic data
Authors: Zerva A. , Beck J. L.
Published: March 2003

A methodology for the identification of random field models for the description of seismic ground motions recorded over extended areas is presented. The approach (i) embeds seismic ground motion parameter estimation in a probabilistic framework, and (ii) identifies simultaneously point and spatial models for the seismic ground motion random field from either smoothed or unsmoothed non‐parametric spectral estimates. It is shown that parametric coherency estimates identified by means of this approach are stable and insensitive to the amount of smoothing performed on the empirical data. The approach and its findings have a significant impact on the evaluation of parametric ground motion models for the seismic response evaluation of lifelines. Copyright © 2003 John Wiley & Sons, Ltd.
Experimental study on multiple tuned mass dampers to reduce seismic responses of a three‐storey building structure
Authors: Chen Genda , Wu Jingning
Published: March 2003

In this study, several mass dampers were designed and fabricated to suppress the seismic responses of a ¼‐scale three‐storey building structure. The dynamic properties of the dampers and structure were identified from free and forced vibration tests. The building structure with or without the dampers was, respectively, tested on a shake table under the white noise excitation, the scaled 1940 El Centro earthquake and the scaled 1952 Taft earthquake. The dampers were placed on the building floors using the sequential procedure developed by the authors in previous studies. Experimental results indicated that the multiple damper system is substantially superior to a single tuned mass damper in mitigating the floor accelerations even though the multiple dampers are sub‐optimal in terms of tuning frequency, damping and placement. These results validated the sequential procedure for placement of the multiple dampers. The structure was also analysed numerically based on the shake table excitation and the identified structure and damper parameters for all test cases. Numerical and experimental results are in good agreement, validating the dynamic properties identified. Copyright © 2003 John Wiley & Sons, Ltd.
Steel frames with bracing mechanism and hysteretic dampers
Authors: Phocas M. C. , Pocanschi A.
Published: March 2003

A new earthquake resistant structural system for multi‐storey frame structures, based on a dual function of its bracing components, is developed. This consists of a hysteretic damper device and a cross‐bracing mechanism with a kinetic closed circuit, working only in tension, so that cable members can be used for this purpose. Solutions are presented regarding the connections' design of three types of structural frame system, that are concerned throughout the study: braced moment free frame, braced moment resisting frame with moment free supports, and with moment resisting supports. The dynamic behaviour of the system is investigated on the basis of an SDOF model, and based on the response spectra method an approximate design approach of the controlled structures is shown. From the time history analysis of the structural systems for the El Centro earthquake the areas of appropriate stiffness relations of the frames to the hysteretic dampers and the cable braces are deduced, so that the energy dissipation of the system may be controlled by the damper‐cable bracing mechanism. Based on the results of these studies, a predesign approach is developed for the implementation of the control system in frame structures. Copyright © 2003 John Wiley & Sons, Ltd.
Changes in geometry and subglacial drainage of Midre Lovénbreen, Svalbard, determined from digital elevation models
Authors: Rippin David , Willis Ian , Arnold Neil , Hodson Andrew , Moore John , Kohler Jack , BjöRnsson Helgi
Published: March 2003

Digital elevation models (DEMs) of the bed and surface of the polythermal Midre Lovénbreen, Svalbard, are used to identify changes in glacier geometry between 1977 and 1995. The calculated mean annual mass balance (−0·61 m water equivalent (w.e.) a−1) is more negative than that derived from field measurements (−0·35 m w.e. a−1), although the error associated with this value (±0·7 m a−1) suggests that the difference may be accounted for by errors. However, similar discrepancies between DEM‐based and field‐based measurements of mass balance have been reported elsewhere in Svalbard. Although errors may be responsible, patterns of surface elevation change may also be explained in terms of patterns of ablation, accumulation, and dynamics. The theoretical structure of the subglacial drainage system is modelled using different assumptions about subglacial water pressure, in 1977 and 1995. These reconstructions are compared with the observed positions of proglacial outlet streams. Decreasing subglacial water pressure results in a decrease in the influence of surface morphology and an increase in the role of the bed topography on drainage routing, which generally leads to more dispersed drainage. Long‐term changes in the position of proglacial outlet streams occur as a result of changes in glacier geometry, but short‐term changes may also occur in response to early season water pressures, controlled by meteorological and hydrological conditions. Copyright © 2003 John Wiley & Sons, Ltd.
From forecasting to foresight processes—new participative foresight activities in Germany
Authors: Cuhls Kerstin
Published: March 2003

The definitions of forecasting vary to a certain extent, but they all have the view into the future in common. The future is unknown, but the broad, general directions can be guessed at and reasonably dealt with. Foresight goes further than forecasting, including aspects of networking and the preparation of decisions concerning the future. This is one reason why, in the 1990s, when foresight focused attention on a national scale in many countries, the wording also changed from forecasting to foresight. Foresight not only looks into the future by using all instruments of futures research, but includes utilizing implementations for the present. What does a result of a futures study mean for the present? Foresight is not planning, but foresight results provide ‘information’ about the future and are therefore one step in the planning and preparation of decisions. In this paper, some of the differences are described in a straightforward manner and demonstrated in the light of the German foresight process ‘Futur’. Copyright © 2003 John Wiley & Sons, Ltd.
Developing futures for agriculture in the Netherlands: a systematic exploration of the strategic value of foresight
Authors: van der Meulen Barend , de Wilt Jan , Rutten Hans
Published: March 2003

Science and Technology Foresight (STF) is an interactive and systematic exploration of future dynamics of science, technology, the economy and society with the aim of identifying and supporting viable strategies and actions for stakeholders. In comparison to futures studies and forecasting, the literature on foresight has paid little attention to its actual strategic value. In this paper we review the 1995–1999 foresight programme of the Dutch National Council for Agricultural Research, and evaluate some key dimensions of the foresight process, including the selection and range of participants, the immediate impact of interactive tools such as workshops and the ultimate effect on the strategic thinking in the agricultural sector. The evaluation indicates that strategic thinking in the Dutch agricultural sector has improved. The paper concludes with suggestions for monitoring and evaluation of foresight that may increase the understanding of foresight's strategic value. Copyright © 2003 John Wiley & Sons, Ltd.
Foresight in a research institution: a critical review of two exercises
Authors: de Lattre‐Gasquet Marie , Petithuguenin Philippe , Sainte‐Beuve Jérôme
Published: March 2003

Foresight is a powerful tool for imagining possible futures, for raising public awareness, for helping decision‐making and addressing questions related to the relationship between science and society. In this article we make a critical analysis of two foresight exercises organized by a research institution. A precise description of the exercises conducted on the futures of the cocoa commodity chain and theheveacommodity chain helps to understand the possible processes of a foresight exercise, what foresight can achieve and what kinds of difficulties can occur. From these experiences, proposals are made to facilitate the development of strategic intelligence in a research institution and improve the linkages between foresight, evaluation and programme formulation. The role of foresight in transforming knowledge and in pushing a closed system into a political arena is also shown. Copyright © 2003 John Wiley & Sons, Ltd.
Innovative methodologies for exploring the future of automated vehicle guidance
Authors: Marchau V. A. W. J. , van der Heijden R. E. C. M.
Published: March 2003

In various countries, transport policy makers are increasingly interested in the automation of vehicle driving tasks. Current policy developments regarding Automated Vehicle Guidance (AVG) are complicated by several uncertainties about the development of AVG technologies, whether their implementation will contribute to or conflict with transport policy goals, and the basic societal conditions that are required for AVG implementation. In this article, we present an approach to reduce the uncertainty regarding alternative AVG implementations. In particular, we develop a backcasting approach to limit the scope of policy development and research by eliminating parts of the large variety in possible AVG developments. This approach consists of the following steps: (1) the specification of plausible AVG concepts; (2) the analysis of the conditions for the implementation of these concepts, resulting in a set of promising AVG concepts and (3) the analysis whether stakeholders' decisions and actions related to the implementation of plausible concepts will be fulfilled in time. This approach helps to eliminate non‐plausible, non‐promising and non‐accepted AVG concepts and reduce the scope of policy making to the most viable ones. Copyright © 2003 John Wiley & Sons, Ltd.
Evolving foresight in a small transition economy
Authors: Havas Attila
Published: March 2003

Hungary launched its first Technology Foresight Programme (TEP) in 1997. This was a holistic foresight programme, based on panel activities and a large‐scale Delphi survey, with a strong emphasis on socio‐economic needs. The paper discusses why a foresight exercise is relevant to a transition country, then describes what was done (organization, methods and results), and how the process evolved in Hungary. Policy conclusions, methodological lessons and questions for further research are also offered. Copyright © 2003 John Wiley & Sons, Ltd.
DNA microarrays for comparative genomic hybridization based on DOP‐PCR amplification of BAC and PAC clones
Authors: Fiegler Heike , Carr Philippa , Douglas Eleanor J. , Burford Deborah C. , Hunt Sarah , Smith James , Vetrie David , Gorman Patricia , Tomlinson Ian P.M. , Carter Nigel P.
Published: March 2003

We have designed DOP‐PCR primers specifically for the amplification of large insert clones for use in the construction of DNA microarrays. A bioinformatic approach was used to construct primers that were efficient in the general amplification of human DNA but were poor at amplifying E. coli DNA, a common contaminant of DNA preparations from large insert clones. We chose the three most selective primers for use in printing DNA microarrays. DNA combined from the amplification of large insert clones by use of these three primers and spotted onto glass slides showed more than a sixfold increase in the human to E. coli hybridization ratio when compared to the standard DOP‐PCR primer, 6MW. The microarrays reproducibly delineated previously characterized gains and deletions in a cancer cell line and identified a small gain not detected by use of conventional CGH. We also describe a method for the bulk testing of the hybridization characteristics of chromosome‐specific clones spotted on microarrays by use of DNA amplified from flow‐sorted chromosomes. Finally, we describe a set of clones selected from the publicly available Golden Path of the human genome at 1‐Mb intervals and a view in the Ensembl genome browser from which data required for the use of these clones in array CGH and other experiments can be downloaded across the Internet. © 2003 Wiley‐Liss, Inc.
Genomic deletions on other chromosomes involved in variant t(9;22) chronic myeloid leukemia cases
Authors: Albano Francesco , Specchia Giorgina , Anelli Luisa , Zagaria Antonella , Storlazzi Clelia Tiziana , Buquicchio Caterina , Roberti Maria Grazia , Liso Vincenzo , Rocchi Mariano
Published: March 2003

The Philadelphia (Ph) chromosome is the cytogenetic hallmark of chronic myeloid leukemia (CML) and is observed in more than 90% of CML cases. At diagnosis, in 5–10% of CML patients the Ph chromosome is derived from variant translocations other than the standard t(9;22). Deletions adjacent to the translocation junction on the derivative chromosome 9 were recently described by different groups. The deletions may identify a subgroup with a worse prognosis. The presence of similar deletions on the third derivative other than the 9 and 22 chromosomes in CML with variant translocation has never been investigated. We studied three cases of CML variants showing relatively large deletions on the third chromosome involved in the translocation. Known tumor‐suppressor genes (TSGs) or genes involved in signal transduction and in the modulation of cell proliferation were found to be located inside these deleted regions. As an alternative to Knudson's two‐hit model, the “haplo‐insufficiency” hypothesis suggests that the deletion of a single allele of a TSG can play an important role in tumor progression. Our findings suggest that great attention should be paid to the molecular cytogenetic characterization of variant t(9;22) CML patients to unveil fully the biological heterogeneity of CML. © 2003 Wiley‐Liss, Inc.
Localized ductile thrusting north of the Variscan Front, Ross Island, southwest Ireland
Authors: Nex Paul A. M. , Kinnaird Judith A. , Ixer Robert A.
Published: March 2003

Two thrusts occur on Ross Island: the Head of Ross Thrust and the more southerly Ross Island Thrust. These lie to the north of the Killarney–Mallow Fault (KMF), the boundary frequently interpreted as the Variscan Front. The Ross Island Thrust, exposed in outcrop and in seven borehole cores, has emplaced dark blue–grey limestones of the Courceyan Ballysteen Formation over pale grey–brown Rockfield Limestone Formation of Chadian–Holkerian age. These lithologies at Ross Island exhibit a continuum of deformation at both the micro‐ and macro‐scale, beginning with the generation of a spaced cleavage, formed during layer parallel shortening, that was subsequently rotated into parallelism with fold axial planes. Extensional microstructures are predominant in thin section and are associated with attenuation of the fold limb. Calcite veins are also attenuated and lie parallel to a mylonitic fabric close to the thrust plane. Lithological boundaries, the prominent pressure solution cleavage and the southerly dipping limb of an asymmetrical antiform are all parallel and form a composite planar anisotropy. This has controlled the location of the ductile Ross Island Thrust, which formed during the attenuation and shearing of a common fold limb. Ductile thrusts within the limestones at Ross Island contrast with the reactivation of basin‐margin extensional faults further to the south along the major KMF. The Ross Island Thrust is considered to result from deformation ahead of the major northerly propagating Variscan décollement thrust and does not necessitate a continuous décollement structure north of the KMF. Mineralization at Ross Island exhibits remobilization associated with the formation of a pressure‐solution cleavage and probably pre‐dates thrusting. Copyright © 2003 John Wiley & Sons, Ltd.
Deformation history of the ophiolite sequence from the Balagne Nappe, northern Corsica: insights in the tectonic evolution of Alpine Corsica
Authors: Marroni M. , Pandolfi L.
Published: March 2003

In Alpine Corsica, the Jurassic ophiolites represent remnants of oceanic lithosphere belonging to the Ligure‐Piemontese Basin located between the Europe/Corsica and Adria continental margins. In the Balagne area, a Jurassic ophiolitic sequence topped by a Late Jurassic–Late Cretaceous sedimentary cover crops out at the top of the nappe pile. The whole ophiolitic succession is affected by polyphase deformation developed under very low‐grade orogenic metamorphic conditions. The original palaeogeographic location and the emplacement mechanisms for the Balagne ophiolites are still a matter of debate and different interpretations for its history have been proposed. The deformation features of the Balagne ophiolites are outlined in order to provide constraints on their history in the framework of the geodynamic evolution of Alpine Corsica. The deformation history reconstructed for the Balagne Nappe includes five different deformation phases, from D1 to D5. The D1 phase was connected with the latest Cretaceous/Palaeocene accretion into the accretionary wedge related to an east‐dipping subduction zone followed by a Late Eocene D2 phase related to emplacement onto the Europe/Corsica continental margin. The subsequent D3 phase was characterized by sinistral strike‐slip faults and related deformations of Late Eocene–Early Oligocene age. The D4 and D5 phases were developed during the Early Oligocene–Late Miocene extensional processes connected with the collapse of the Alpine belt. Copyright © 2003 John Wiley & Sons, Ltd.
Functional somatotopy of finger representations in human primary motor cortex
Authors: Dechent Peter , Frahm Jens
Published: March 2003

To assess the degree of fine‐scale somatotopy within the hand area of the human primary motor cortex (M1), functional mapping of individual movements of all fingers was performed in healthy young subjects (n = 7) using MRI at 0.8 × 0.8 mm2 resolution and 4 mm section thickness. The experimental design comprised both a direct paradigm contrasting single digit movements vs. motor rest and multiple differential paradigms contrasting single digit movements vs. the movement of another digit. Direct mapping resulted in largely overlapping activations. A somatotopic arrangement was only recognizable when considering the mean center‐of‐mass coordinates of individual digit representations averaged across subjects. In contrast, differential paradigms revealed more segregated and somatotopically ordered activations in single subjects. The use of center‐of‐mass coordinates yielded inter‐digit distances ranging from 2.0 to 16.8 mm, which reached statistical significance for pairs of more distant digits. For the middle fingers, the functional somatotopy obtained by differential mapping was dependent on the choice of the digit used for control. These results confirm previous concepts that finger somatotopy in the human M1 hand area emerges as a functional predominance of individual digit representations sharing common areas in a distributed though ordered network. Hum. Brain Mapping 18:272–283, 2003. © 2003 Wiley‐Liss, Inc.
Independent component model for cognitive functions of multiple subjects using [15O]H2O PET images
Authors: Park Hae‐Jeong , Kim Jae‐Jin , Youn Tak , Lee Dong Soo , Lee Myung Chul , Kwon Jun Soo
Published: March 2003

An independent component model of multiple subjects' positron emission tomography (PET) images is proposed to explore the overall functional components involved in a task and to explain subject specific variations of metabolic activities under altered experimental conditions utilizing the Independent component analysis (ICA) concept. As PET images represent time‐compressed activities of several cognitive components, we derived a mathematical model to decompose functional components from cross‐sectional images based on two fundamental hypotheses: (1) all subjects share basic functional components that are common to subjects and spatially independent of each other in relation to the given experimental task, and (2) all subjects share common functional components throughout tasks which are also spatially independent. The variations of hemodynamic activities according to subjects or tasks can be explained by the variations in the usage weight of the functional components. We investigated the plausibility of the model using serial cognitive experiments of simple object perception, object recognition, two‐back working memory, and divided attention of a syntactic process. We found that the independent component model satisfactorily explained the functional components involved in the task and discuss here the application of ICA in multiple subjects' PET images to explore the functional association of brain activations. Hum. Brain Mapping 18:284–295, 2003. © 2003 Wiley‐Liss, Inc.
Preserved performance in a hippocampal‐dependent spatial task despite complete place cell remapping
Authors: Jeffery Kathryn J. , Gilbert Alexandra , Burton Stephen , Strudwick Anna
Published: March 2003

The spatially localized firing of hippocampal place cells is thought to underlie the navigational function of the hippocampus. Performance on a spatial task learned using a particular place cell map should therefore deteriorate if the map is disrupted. To test this prediction, we trained rats on a hippocampal‐dependent spatial task in a black box and tested them in a white box. Although the change from black to white induced remapping of most place cells, navigational performance remained essentially intact. Furthermore, place cell activity was also unrelated to specific aspects of the task such as tone onset, response, or goal location. Together, these results imply that the spatial information needed to solve this navigation task is represented outside the hippocampus and suggest that the place cells encode some other aspect, such as the spatial context. Hippocampus 2003;13:175–189. © 2003 Wiley‐Liss, Inc.
Hippocampal lesions and discrimination performance of mice in the radial maze: Sparing or impairment depending on the representational demands of the task
Authors: Etchamendy Nicole , Desmedt Aline , Cortes‐Torrea Cedric , Marighetto Aline , Jaffard Robert
Published: March 2003

The effects of ibotenate hippocampal lesions on discrimination performance in an eight‐arm radial maze were investigated in mice, using a three‐stage paradigm in which the only parameter that varied among stages was the way the arms were presented. In the initial learning phase (stage 1), animals learned the valence or reward contingency associated with six (three positive and three negative) adjacent arms of the maze using a successive (go/no‐go) discrimination procedure. In the first test phase (stage 2), the six arms were grouped into three pairs, so that on each trial, the subject was faced with a choice between two adjacent arms of opposite valence (concurrent two‐choice discrimination). In the second test phase (stage 3), the subject was faced with all six arms simultaneously (six‐choice discrimination). Hippocampal‐lesioned mice acquired the initial learning phase at a near‐normal rate but behaved as if they had learned nothing when challenged with the two‐choice discriminations at stage 2. In contrast, they behaved normally when confronted with the six‐choice discrimination at stage 3. Detailed examination of within‐ and between‐stage performance suggests that hippocampal‐lesioned mice perform as intact mice when presentation of the discriminanda encourages the storage and use of separate representations (i.e., in initial learning and six‐choice discrimination testing), but that they fail in test situations that involve explicit comparisons between such separate representations (two‐choice discriminations), hence requiring the use of relational representations. Hippocampus 2003;13:197–211. © 2003 Wiley‐Liss, Inc.
Temporal spacing of synaptic stimulation critically modulates the dependence of LTP on cyclic AMP‐dependent protein kinase
Authors: Woo Newton H. , Duffy Steven N. , Abel Ted , Nguyen Peter V.
Published: March 2003

Genetic and electrophysiological experiments have defined an important role for cAMP‐dependent protein kinase (PKA) in certain forms of long‐term potentiation (LTP). However, the characteristics of stimulation that are critical for regulating the PKA‐dependence of LTP have not been clearly defined. In the present study, we have used PKA mutant mice (R(AB) transgenic mice), which have reduced PKA activity in neurons within the hippocampus, to explore the role of temporal spacing of synaptic stimulation in regulating the PKA‐dependence of LTP. The time interval between successive bursts of electrical stimulation was varied while keeping constant the total number of stimulus pulses. LTP induced by temporally spaced tetraburst synaptic stimulation was impaired in the Schaeffer collateral pathway of hippocampal slices from R(AB) mutant mice. In contrast, LTP induced by temporally compressed tetraburst stimulation was normal in slices from R(AB) mutants, and its long‐term maintenance was not significantly affected by bath application of KT‐5720, an inhibitor of catalytic subunits of PKA. In slices from wildtype mice, LTP induced by spaced tetraburst stimulation was significantly attenuated by KT‐5720. These genetic and pharmacological experiments show that LTP induced by these compressed patterns of stimulation does not require PKA activation. Thus, altering the temporal spacing of synaptic stimulation per se critically modulates the PKA‐dependence of hippocampal LTP. PKA‐dependent LTP is selectively recruited by temporally spaced, multiburst synaptic stimulation. Hippocampus 2003;13:293–300. © 2003 Wiley‐Liss, Inc.
Synthesis and Odor Evaluation of Stereoisomers of Imine Derivatives in Roasted Spotted Shrimp
Authors: Tachihara Toru , Ishizaki Susumu , Kurobayashi Yoshiko , Tamura Hiroshi , Ikemoto Youichi , Onuma Atsushi , Yoshikawa Keisuke , Yanai Tetsuya , Kitahara Takeshi
Published: March 2003

All possible stereoisomers of imine derivatives 1–4, which have the characteristic roast odor of seafood, were synthesized. As a result of odor evaluation of all isomers, we found that each isomer has a different and characteristic odor of roasted seafood.
Isolation and Structural Characterization of New, Highly Functionalized Diterpenes from Euphorbia serrulata
Authors: Rédei Dóra , Hohmann Judit , Evanics Ferenc , Forgo Peter , Szabó Pál , Máthé Imre
Published: March 2003

Five new diterpene polyesters, 1–5, with jatrophane skeletons were isolated from the fresh whole plants of Euphorbia serrulata. The structure elucidation was performed by means of UV/VIS spectroscopy, HR‐ESI‐MS, and advanced two‐dimensional NMR methods, including 1H‐NMR, JMOD, 1H,1H‐COSY, NOESY, HMQC, and HMBC experiments. The relative configurations of 1–5 and their conformations in solution were analyzed on the basis of NOESY measurements. As a result of detailed NMR studies, complete 1H and 13C chemical‐shift assignments of the compounds were possible. The isolated compounds differ stereochemically and do not comprise a uniform series regarding the configurations at C(2), C(6), and C(13). Compound 5 possesses the new structural feature of a double bond with (Z)‐configuration in the macrocyclic ring of the jatrophane skeleton, while compound 2 has a CC bond in the five‐membered ring, this being the first observation of this structural feature in the type of macrocyclic Euphorbiaceae diterpenes.
Sequential Rearrangement Reactions of Benzhomonorbornadiene Derivatives: Synthesis of 7‐Vinylbenzonorbornadiene
Authors: Menzek Abdullah , Gökmen Melek
Published: March 2003

The reaction of alcohol 12 with SOCl2 gave chlorides 13 and 14, and the acetolysis of toluene‐4‐sulfonate 15 gave sequential rearrangement products 16, 17, and 18. In the reaction of 12, 13 is the major product of sequential rearrangements. Treatment of chloride 13 with t‐BuOK gave 7‐vinylbenzonorbornadiene 19.
Stereoselective Synthesis of (3R)‐3,4‐Dihydro‐6,8‐dimethoxy‐3‐undecyl‐ 1H‐[2]benzopyran‐1‐one and Derivatives, Metabolites from Ononis natrix
Authors: Saeed Aamer
Published: March 2003

A short stereoselective synthesis of (3R)‐3,4‐dihydro‐6,8‐dimethoxy‐3‐undecyl‐1H‐[2]benzopyran‐1‐one and derivatives isolated from Ononis natrix has been described. Condensation of dodecanoyl chloride with 3,5‐dimethoxyhomophthalic acid afforded 6,8‐dimethoxy‐3‐undecylisocoumarin 3, which, on sequential saponification and esterification, yielded the keto ester 5. Enantioselective reduction of 5 with TarB‐NO2/LiBH4 directly furnished the title dihydroisocoumarin 1a in 80% ee (82% yield). Partial as well as complete demethylation of the latter provided the dihydroisocoumarins 1b and 1c, respectively. Diastereotopy of the CH2 H‐atoms on either side of the stereogenic center (C(3)) and the mass‐fragmentation pattern of the dihydroisocoumarins have also been described. All of the compounds synthesized were examined in vitro for antifungal activity.
Novel Polyoxygenated Spirostanol Glycosides from the Rhizomes of Helleborus orientalis
Authors: Mimaki Yoshihiro , Watanabe Kazuki , Sakuma Chiseko , Sakagami Hiroshi , Sashida Yutaka
Published: March 2003

The two new polyoxygenated spirostanol bisdesmosides 1 and 2 and the new trisdesmoside 3, named hellebosaponin A (1), B (2), and C (3), respectively, were isolated from the MeOH extract of the rhizomes of Helleborus orientalis. The structures of the new compounds were elucidated as (1β,3β,23S,24S)‐21‐(acetyloxy)‐24‐[(β‐D‐fucopyranosyl)oxy]‐3,23‐dihydroxyspirosta‐5,25(27)‐dien‐1‐yl O‐β‐D‐apiofuranosyl‐(1→3)‐O‐(4‐O‐acetyl‐α‐L‐rhamnopyranosyl)‐(1→2)‐O‐[β‐D‐xylopyranosyl‐(1→3)]‐α‐L‐arabinopyranoside (1), (1β,3β,23S,24S)‐ 21‐(acetyloxy)‐24‐{[O‐β‐D‐glucopyranosyl‐(1→4)‐β‐D‐fucopyranosyl]oxy}‐3,23‐dihydroxyspirosta‐5,25(27)‐dien‐1‐yl O‐β‐D‐apiofuranosyl‐(1→3)‐O‐(4‐O‐acetyl‐α‐L‐rhamnopyranosyl)‐(1→2)‐O‐[β‐D‐xylopyranosyl‐(1→3)]‐ α‐L‐arabinopyranoside (2), and (1β,3β,23S,24S)‐24‐[(β‐D‐fucopyranosyl)oxy]‐21‐{[O‐β‐D‐glucopyranosyl‐(1→2)‐β‐D‐galactopyranosyl]oxy}‐3,23‐dihydroxyspirosta‐5,25(27)‐dien‐1‐yl O‐β‐D‐apiofuranosyl‐(1→3)‐O‐(4‐O‐acetyl‐α‐L‐rhamnopyranosyl)‐(1→2)‐O‐[β‐D‐xylopyranosyl‐(1→3)]‐α‐L‐arabinopyranoside (3), respectively, on the basis of detailed spectroscopic studies and chemical evidence.
Henrycinols A and B, Two Novel Indole Alkaloids Isolated from Melodinus henryiCraib
Authors: Zhang Yan Wen , Yang Rui , Cheng Qian , Ofuji Katsuya
Published: March 2003

Henrycinols A (1) and B (2), two novel indole alkaloids, together with three known compounds, (+)‐Δ14‐vincamine (3), (+)‐16‐epi‐Δ14‐vincamine (4), and (+)‐isoeburnamine (5), were isolated from the roots of Melodinus henryi Craib. Their structures were established on the basis of 1D‐ and 2D‐NMR spectroscopic analysis. The relative configuration of henrycinols A and B was determined by NOESY analysis.
Three Tyrosinase Inhibitors and Antioxidant Compounds from Salsola foetida
Authors: Khan Khalid Mohammed , Maharvi Ghulam Murtaza , Abbaskhan Ahmed , Hayat Safdar , Khan Mahmud Tareq Hassan , Makhmoor Talat , Choudhary M. Iqbal , Shaheen Farzana , Atta‐ur‐Rahman
Published: March 2003

Phytochemical investigation on the whole plant of Salsola foetida resulted in the isolation of three new phenolic compounds 1, 2, and 3, which exhibit tyrosinase inhibition with moderate antioxidant activity. Compounds 1–3 inhibited tyrosinase with IC50 2.61, 1.85, and 0.40 μM, while exhibiting DPPH radical scavenging activity with IC50 383, 427 and 378 μM, respectively. The structures of 1, 2, and 3 were determined by modern spectroscopic techniques.
Synthesis and Properties of O‐β‐D‐ribofuranosyl‐(1″→2′)‐guanosine‐5″‐ O‐phosphate and Its Derivatives
Authors: Efimtseva Ekaterina V. , Shelkunova Alexandra A. , Mikhailov Sergey N. , Nauwelaerts Koen , Rozenski Jef , Lescrinier Eveline , Herdewijn Piet
Published: March 2003

The efficient synthesis of O‐β‐D‐ribofuranosyl‐(1″→2′)‐guanosine‐5″‐O‐phosphate and O‐β‐D‐ribofuranosyl‐(1″→2′)‐adenosine‐5″‐O‐phosphate, minor tRNA components, have been developed, and their conformational properties were examined by NMR spectroscopy.
Synthetic Gallic Acid Derivatives as Models for a Comprehensive Study of Antioxidant Activity
Authors: Belin Florence , Barthélémy Philippe , Ruiz Karine , Lacombe Jean Michel , Pucci Bernard
Published: March 2003

The synthesis and antioxidant efficiencies of amphiphilic gallic acid derivatives are reported. To specify the impact of chemical structure on the antioxidant efficiency, several structural modifications of gallic acid were performed. The following structural features were chosen: i) introduction of hydrophobic or hydrophilic residues on the gallic acid and the type of their linkage, ii) the hydrophilic and/or lipophilic character of the whole molecule. The physico‐chemical studies of the different series prepared revealed that the antioxidant efficiency of this polyphenol depends clearly on the nature of the linkage with both hydrophilic and hydrophobic parts. A push‐pull effect is always necessary, and ester or amide bonds seem well adapted to increase the antioxidant efficiency. Second, under the oxidation conditions applied, it was observed that the hydrophilic and/or lipophilic character affects drastically the antioxidant activity of gallic acid derivatives. The results obtained are in accordance with the polar paradox, hydrophobic derivatives inhibit oxidation in an aqueous phase, whereas hydrophilic products are not efficient.
T cells in myeloma
Authors: Raitakari M. , Brown R. D. , Gibson J. , Joshua D. E.
Published: March 2003

The current trend to develop immunotherapy strategies for patients with myeloma and other B cell malignancies has stimulated considerable interest in the functional state of the T cell population in these patients. Expanded clones of T cells exist in many patients with myeloma and their presence is associated with an improved survival. However, isolating T cells with tumour specificity has proven to be a difficult task and clinical immunization trials have so far failed to achieve a significant response. There is now evidence that tumour specific T cells are either tolerized or deleted following antigen presentation and that idiotype‐derived, immunodominant tumour peptides may not exist in all patients. In order to develop more effective immunotherapy strategies for patients with myeloma, further studies are urgently required to identify the most appropriate tumour antigen, the nature of the interactions which take place during antigen presentation, and how to promote the cytotoxicity of autologous T cells. Copyright © 2003 John Wiley & Sons, Ltd.
The impact of self‐assessment on provider performance in Mali
Authors: Kelley Edward , Kelley Allison Gamble , Simpara Cheick H. T. , Sidibé Ousmane , Makinen Marty
Published: March 2003

Improving the quality of clinical care in developing country settings is a difficult task, both in public sector settings where supervision is infrequent and in private sector settings where supervision and certification are non‐existent. This study tested a low‐cost method, self‐assessment, for improving the quality of care that providers offer in a peri‐urban area in Mali. The study was a cross‐sectional, case–control study on the impact of self‐assessment on compliance with the quality of care standards. The two indicators of interest were the compliance with fever care standards and the compliance with structural quality standards. Both standards were derived from the Ministry of Health of Mali's standards for health care delivery. The study examined 36 providers, 12 of whom were part of the intervention and 24 of whom were part of the control group over a 3 month period from May to July 2001. Overall, the research team found a significant difference between the intervention and control groups in terms of overall compliance (p < 0.001) and in terms of assessment of fever (p < 0.005). The total costs for the intervention for 36 providers was less than US$250, which translated to approximately $6 per provider. The data appear to suggest that self‐assessment, when used in a regular fashion, can have a significant effect on compliance with standards. However, it is clear that self‐assessment is not a resource‐neutral intervention. All of the individuals from the intervention pool interviewed cited the extra work that they had to do to comply with the intervention protocol as a burden. In particular, study participants put an emphasis on the ‘long duration’ of the study that ‘discouraged’ the study participants. Future research on self‐assessment should include a larger sample of providers and should examine the impact of self‐assessment over time. Copyright © 2003 John Wiley & Sons, Ltd.
Costs of maternal health care services in three anglophone African countries
Authors: Levin Ann , Dmytraczenko Tania , McEuen Mark , Ssengooba Freddie , Mangani Ronald , Van Dyck Gerry
Published: March 2003

This paper is a synthesis of a case study of provider and consumer costs, along with selected quality indicators, for six maternal health services provided at one public hospital, one mission hospital, one public health centre and one mission centre, in Uganda, Malawi and Ghana. The study examines the costs of providing the services in a selected number of facilities in order to examine the reasons behind cost differences, assess the efficiency of service delivery, and determine whether management improvements might achieve cost savings without hurting quality. This assessment is important to African countries with ambitious goals for improving maternal health but scarce public health resources and limited government budgets. The study also evaluates the costs that consumers pay to use the maternal health services, along with the contribution that revenues from fees for services make to recovering health facility costs.

The authors find that costs differ between hospitals and health centres as well as among mission and public facilities in the study sample. The variation is explained by differences in the role of the facility, use and availability of materials and equipment, number and level of personnel delivering services, and utilization levels of services. The report concludes with several policy implications for improvements in efficiency, financing options and consumer costs. Copyright © 2003 John Wiley & Sons, Ltd.
Recharge of aquifers by flood events in an arid region
Authors: Shentsis Isabella , Rosenthal Eliyahu
Published: March 2003

The process of aquifer recharge by flood events in an arid region was investigated as applied to the Hazeva Formation (the Karkom graben, the Wadi Paran watershed, Israel). The hydrological model was established as a complex system, with due regard for groundwater and transmission losses of surface runoff. It was based on a previously outlined hydrogeological model of the Karkom graben and a model of transmission losses in arid watercourses under conditions of data deficiency. Proceeding from calculation of groundwater balances, the contribution of surface runoff as a decisive balance component was confirmed. The main characteristics of aquifer regimes, such as changes in storage volume and groundwater level, as well as lateral flow, were all found to be dependent upon the net extraction rate, i.e. pumpage discounting replenishment by flood events. Analysis and physical interpretation of model parameters enabled assessment of the influence of groundwater extraction on aquifer recharge. This became apparent as increasing absorption capacity and recharge availability of the aquifer as a result of the groundwater abstraction. Copyright © 2002 John Wiley & Sons, Ltd.
Increasing transmission losses from flood events due to groundwater extraction
Authors: Shentsis Isabella
Published: March 2003

This study continues the examination of the influence of groundwater exploitation upon the process of aquifer recharge by flood events. In the course of the developing an earlier hydrological model for the Hazeva Formation aquifer (the Wadi Paran watershed, southern Israel), it became apparent that groundwater extraction influenced absorption capacity of sub‐aquifers and regulated the distribution of percolating surface water between units. The present study lends numerical proof regarding the influence of Hazeva aquifer exploitation upon the regime of runoff and enhancement of transmission losses from flood events in Wadi Paran, and, as a result, upon increased recharge to the aquifer. Copyright © 2002 John Wiley & Sons, Ltd.