bluuebunny/crossref_metadata_2025 huggingface dataset:
NMR assessment of the global shape of a non‐labelled DNA dodecamer containing a tandem of GT mismatches
Authors: Alvarez‐Salgado Francisco , Desvaux Hervé , Boulard Yves
Published: September 2006

We have carried out a solution study of two non‐labelled self‐complementary DNA dodecamers d(GACTGTACAGTC)2 and d(GACTGTGCAGTC)2 by NMR, the second sequence composed of two GT mismatches. Structures were determined using distances extracted from NOE effects alone or using both NOE and RDC constraints, measured in three different liquid crystalline media. We ensured that our data on the influence of the mesogen on the DNA structures, and the way in which the RDCs were incorporated as constraints in the protocol refinement, were consistent. We also tested the influence of different sets of RDCs and the best means of optimizing the calculation of Da and R. Resolution and accuracy of the ten best energy final structures were compared. The addition of a small set of RDC constraints significantly improves the final determined structures. We took advantage of the specificity of the RDC, i.e. it contains orientational information, and explored the global shape of the DNA duplexes; it was found that the duplexes do not have a large curvature. For the GT base pair, we observed, in this particular sequence (tandem of GT mismatches), a new pattern of base pairing, which involved the formation of a bifurcated hydrogen bond. Copyright © 2006 John Wiley & Sons, Ltd.
Discontinuous Galerkin framework for adaptive solution of parabolic problems
Authors: Kulkarni Deepak V. , Rovas Dimitrios V. , Tortorelli Daniel A.
Published: September 2006

Non‐conforming meshes are frequently employed in adaptive analyses and simulations of multi‐component systems. We develop a discontinuous Galerkin formulation for the discretization of parabolic problems that weakly enforces continuity across non‐conforming mesh interfaces. A benefit of the DG scheme is that it does not introduce constraint equations and their resulting Lagrange multiplier fields as done in mixed and mortar methods. The salient features of the formulation are highlighted through an a priori analysis. When coupled with a mesh refinement scheme the DG formulation is able to accommodate multiple hanging nodes per element edge and leads to an effective adaptive framework for the analysis of interface evolution problems. We demonstrate our approach by analysing the Stefan problem of solidification. Copyright © 2006 John Wiley & Sons, Ltd.
Reduction of substructural interface degrees of freedom in flexibility‐based component mode synthesis
Authors: Markovic Damijan , Park K. C. , Ibrahimbegovic Adnan
Published: September 2006

A flexibility‐based component mode synthesis (CMS) is proposed for reduced‐order modelling of dynamic behaviour of large structures. The approach employs partitioning via the localized Lagrange multiplier method. The use of the localized Lagrange multipliers leads to, unlike the classical Lagrange multipliers, a linearly independent set of interface forces without any redundancies at multiply connected interface nodes. The flexibility‐based CMS method has shown significant advantages over the classical Craig–Bampton method. A key feature of the method is its substructural mode selection criterion that is independent of loading conditions. Unlike the majority of available CMS approaches, where one retains the full dimension of partition boundary degrees of freedom (DOFs), the flexibility‐based method allows to reduce significantly the interface DOFs. The reduction of interface DOFs represents the major contribution of the present communication. The efficiency of the proposed approach is demonstrated on an analysis of a simple plate partitioned and of a more complex 3D structure, both partitioned into several substructures. Copyright © 2006 John Wiley & Sons, Ltd.
Gene profiling of cathepsin K deficiency in atherogenesis: profibrotic but lipogenic
Authors: Lutgens SPM , Kisters N , Lutgens E , van Haaften RIM , Evelo CTA , de Winther MPJ , Saftig P , Daemen MJAP , Heeneman S , Cleutjens KBJM
Published: September 2006

Recently, we showed that cathepsin K deficiency reduces atherosclerotic plaque progression, induces plaque fibrosis, but aggravates macrophage foam cell formation in the ApoE −/− mouse. To obtain more insight into the molecular mechanisms by which cathepsin K disruption evokes the observed phenotypic changes, we used microarray analysis for gene expression profiling of aortic arches of CatK −/−/ApoE −/− and ApoE −/− mice on a mouse oligo microarray. Out of 20 280 reporters, 444 were significantly differentially expressed (p‐value of < 0.05, fold change of ≥ 1.4 or ⩽− 1.4, and intensity value of > 2.5 times background in at least one channel). Ingenuity Pathway Analysis and GenMAPP revealed upregulation of genes involved in lipid uptake, trafficking, and intracellular storage, including caveolin − 1, − 2, − 3 and CD36, and profibrotic genes involved in transforming growth factor β (TGFβ) signalling, including TGFβ2, latent TGFβ binding protein‐1 (LTBP1), and secreted protein, acidic and rich in cysteine (SPARC), in CatK −/−/ApoE −/− mice. Differential gene expression was confirmed at the mRNA and protein levels. In vitro modified low density lipoprotein (LDL) uptake assays, using bone marrow derived macrophages preincubated with caveolae and scavenger receptor inhibitors, confirmed the importance of caveolins and CD36 in increasing modified LDL uptake in the absence of cathepsin K. In conclusion, we suggest that cathepsin K deficiency alters plaque phenotype not only by decreasing proteolytic activity, but also by stimulating TGFβ signalling. Besides this profibrotic effect, cathepsin K deficiency has a lipogenic effect owing to increased lipid uptake mediated by CD36 and caveolins. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Proteomics and metabolomics: The molecular make‐up of toxic aromatic pollutant bioremediation
Authors: Singh Om V.
Published: September 2006

Microbial‐mediated attenuation of toxic aromatic pollutants offers great potential for the restoration of contaminated environments in an ecologically acceptable manner. However, incomplete biological information regarding the regulation of growth and metabolism in many microbial communities restricts progress in the site‐specific mineralization process. In the postgenomic era, recent advances in MS have allowed enormous progress in proteomics and elucidated many complex biological interactions. These research forefronts are now expanding toward the analysis of low‐molecular‐weight primary and secondary metabolites analysis, i.e., metabolomics. The advent of 2‐DE in conjunction with MS offers a promising approach to address the molecular mechanisms of bioremediation. The two fields of proteomics and metabolomics have thus far worked separately to identify proteins and primary and secondary metabolites during bioremediation. A simultaneous study combining functional proteomics and metabolomics, i.e., proteometabolomics would create a system‐wide approach to studying site‐specific microorganisms during active mineralization processes. This article deals with advances in environmental proteomics and metabolomics and advocates the simultaneous study of both technologies to implement cell‐free bioremediation.
Proteomic analysis of cancer tissues: Shedding light on carcinogenesis and possible biomarkers
Authors: Kuramitsu Yasuhiro , Nakamura Kazuyuki
Published: September 2006

Lung, gastric, colorectal, pancreatic, and esophageal cancers, as well as hepatocellular carcinoma (HCC), were the six most common and highly fatal cancers for Japanese men in Japan in 2003, while for women uterine cervical cancer could also be added to this list. To identify diagnostic or therapeutic biomarkers for these cancers, investigators are nowadays performing proteomic analyses of cancer tissues and cells, and revealing a large number of molecules which are diagnostic, prognostic and informative of carcinogenesis. From reports of proteomic analyses of cancerous tissues and noncancerous tissues sampled from HCC, and pancreatic, esophageal, gastric, colorectal, lung and uterine cervical cancers, we classified the proteins into digestive enzymes, growth factors, cell adhesion molecules, calcium‐binding proteins, proteases, protease inhibitors, transporter proteins, structural molecules, apoptosis inhibitor, molecular chaperone, as well as proteins related to cell growth, cell differentiation, cell transformation, tumor invasion, carcinogen metabolism, and others. The aim of this study was to understand carcinogenesis of major cancers from a proteomics perspective using samples from cancer patients, and to elucidate their tumor biomarkers.
Chemistry meets proteomics: The use of chemical tagging reactions for MS‐based proteomics
Authors: Leitner Alexander , Lindner Wolfgang
Published: September 2006

As proteomics matures from a purely descriptive to a function‐oriented discipline of the life sciences, there is strong demand for novel methodologies that increase the depth of information that can be obtained from proteomic studies. MS has long played a central role for protein identification and characterization, often in combination with dedicated chemical modification reactions. Today, chemistry is helping to advance the field of proteomics in numerous ways. In this review, we focus on those methodologies that have a significant impact for the large‐scale study of proteins and peptides. This includes approaches that allow the introduction of affinity tags for the enrichment of subclasses of peptides or proteins and strategies for in vitro stable isotope labeling for quantification purposes, among others. Particular attention is given to the study of PTMs where recent advancements have been promising, but many interesting targets are not yet being addressed.
Hole growth as a microrheological probe to measure the viscosity of polymers confined to thin films
Authors: Roth Connie B. , Dutcher John R.
Published: September 2006

We review recent hole growth measurements performed at elevated temperatures in freely‐standing polystyrene (PS) films, using optical microscopy and a differential pressure experiment (DPE). In the hole growth experiments, which were performed at temperatures close to the bulk glass‐transition temperature of PS, T = 97 °C, we find evidence for nonlinear viscoelastic effects, which markedly affect the growth of holes in freely‐standing PS films. The hole radius R initially grew linearly with time t before undergoing a transition to exponential growth characterized by a growth time τ. The time scale τ1 for the decay of the initial transient behavior prior to reaching steady state was consistent with the convective constraint release mechanism of the tube theory of entangled polymer dynamics, while the characteristic hole growth times τ of the holes were consistent with significant reductions in viscosity of over eight orders of magnitude with increasing shear strain rate due to shear thinning. DPE measurements of hole growth on very thin freely‐standing films revealed that hole formation and growth occurs only at temperatures that are comparable to or greater than T, even for films for which the Tg value was reduced by many tens of degrees Celsius below the bulk value. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B:Polym Phys 44: 3011–3021, 2006
Novel catalysts for low temperature synthesis of single wall carbon nanotubes
Authors: Rümmeli M. H. , Grüneis A. , Löffler M. , Jost O. , Schönfelder R. , Kramberger C. , Grimm D. , Gemming T. , Barreiro A. , Borowiak‐Palen E. , Kalbác M. , Ayala P. , Hübers H.‐W. , Büchner B. , Pichler T.
Published: September 2006

Low temperature single wall carbon nanotubes (SWCNT) synthesis is attractive as it would allow their synthesis to be compatible with microelectronics (below 500 °C) or biomolecular electronics (160 °C). We show that the presence of oxygen, introduced in the form of metal oxides, allows metals not normally associated with nanotubes synthesis to become active for the synthesis of SWCNT using laser ablation. Further, the results show metals with low melting points can be used, enabling SWCNT to be synthesized at low temperature (down to room temperature). At these low temperatures their nucleation cannot be explained via fullerene nucleation. We suggest a growth mechanism that places a stable oxidized ring as the root cause for the growth of SWCNT. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pressure‐dependent infrared spectroscopy on the fullerene rotor–stator compound C60–C8H8
Authors: Kuntscher C. A. , Frank S. , Kamarás K. , Klupp G. , Kováts É. , Pekker S. , Bényei Gy. , Jalsovszky I.
Published: September 2006

We carried out infrared transmission measurements of C60–C8H8 as a function of pressure (0–10 GPa) at room temperature. The kinks in the pressure dependences of the frequencies of the molecular vibrations suggest the occurrence of an orientational ordering transition at around 0.8 GPa. The change in the infrared spectrum indicates symmetry lowering in the high‐pressure phase. Furthermore, our data show that the vibrations of C8H8 survive up to a higher pressure than those of C60, suggesting a shielding of the C8H8 molecules against pressure. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence microscopy of as‐grown individual single‐walled carbon nanotubes on Si/SiO2 substrates
Authors: Kiowski Oliver , Lebedkin Sergei , Kappes Manfred M.
Published: September 2006

We present far‐field photoluminescence (PL) imaging at room temperature of tens of micrometer long individual single‐walled carbon nanotubes (SWNTs) grown and measured directly on a Si/SiO2 surface. The SWNTs are grown by Chemical Vapour Deposition (CVD) with ethanol as carbon source and contact the surface with their full length. We detect the PL and its variations along SWNTs in a home‐built laser microscope with a spatial resolution of ∼400 nm. We are able to reliably assign (n, m)‐structure of SWNTs by measuring PL spectra in the range of 800–1600 nm as function of the excitation wavelength varying between 710 and 860 nm. This allows us to check structural integrity (changes of helicity) along the tube. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical transport measurements of nanotubes with known (n, m) indices
Authors: Chandra Bhupesh , Caldwell Robert , Huang Mingyuan , Huang Limin , Sfeir Matthew Y. , O'Brien Stephen P. , Heinz Tony F. , Hone James
Published: September 2006

Because subtle changes in physical structure (chirality) can cause the electronic structure of carbon nanotubes to vary from metallic to semiconducting, the goal of fully controlled nanotube device fabrication has proved elusive. Using a mechanical transfer technique in parallel with optical characterization, we have achieved the goal of placing ‘the nanotube we want, where we want it’. Long nanotubes are grown by CVD across a slit etched through a Si wafer and then examined by Rayleigh scattering. By combining this technique with structural characterization by electron diffraction, we are able to map each spectrum to a unique (n, m) structure. After structural characterization, a chosen nanotube can be transferred to a substrate in the desired location, and devices fabricated using standard e‐beam lithography techniques. We have fabricated a number of devices in this manner and are beginning to fully explore the detailed relationship between structure and transport. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of electron and ultraviolet irradiation on aligned carbon nanotube fibers
Authors: Mikó Csilla , Seo Jin Won , Gaál Richárd , Kulik Andrzej , Forró László
Published: September 2006

We carried out in situ Young's modulus and electrical resistivity measurements on macroscopic oriented ropes of singlewall carbon nanotubes under ultraviolet irradiation. Increases of both the electrical conductivity and the mechanical strength have been observed. These phenomena are explained by the photochemistry between the functional groups on the surface of singelwall nanotubes and dimethyl‐formamide molecules are trapped between the nanotubes. In contrast to high energy electrons during electron irradiation, the photon energy of the ultraviolet irradiation is not sufficient to displace the carbon atoms in the nanotube, therefore the graphitic structure of the tubes remains intact. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carbon nanotube optoelectronics
Authors: Avouris Ph. , Chen J. , Freitag M. , Perebeinos V. , Tsang J. C.
Published: September 2006

In this tutorial we review the optical and electro‐optical properties of single‐walled carbon nanotubes (CNTs). The nature of the excited states of CNTs, their production by photon and electrical excitation and their decay are analyzed. Two types of single CNT light emitters based on ambipolar e–h recombination and a novel unipolar internal impact excitation mechanism are discussed. The reverse process of light detection through photoconduction is also briefly considered. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Four‐terminal measurements of SWNTs using MWNTs as voltage electrodes
Authors: Gao B. , Chen Y. F. , Fuhrer M. S. , Glattli D. C. , Bachtold A.
Published: September 2006

We report on electron transport measurements of single‐wall carbon nanotubes in a four‐terminal configuration with noninvasive voltage electrodes. The voltage drop is detected using multiwalled carbon nanotubes while the current is injected through nanofabricated Au electrodes. Measurements are carried at high temperature so that the four‐terminal resistance directly gives the intrinsic resistance. The resistance is shown to result from weak disorder and from quantum interference effect corrections. In addition, we present Coulomb blockade measurements. The length of the quantum dot that is determined from the level spacing equals the separation between the Au electrodes. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
DNA‐decorated carbon nanotubes for chemical sensing
Authors: Johnson A. T. Charlie , Staii Cristian , Chen Michelle , Khamis Sam , Johnson Robert , Klein M. L. , Gelperin A.
Published: September 2006

We demonstrate a versatile class of nanoscale chemical sensors based on single‐stranded DNA (ssDNA) for chemical recognition and single‐walled carbon nanotube field effect transistors (SWNT FETs) for electronic read‐out. SWNT FETs with a nanoscale coating of ssDNA respond to vapors that cause no detectable conductivity change in bare devices. Sensor responses differ in sign and magnitude for different gases and can be tuned by choice of the ssDNA base sequence. Sensors respond and recover rapidly (seconds), and the sensor surface is self‐regenerating. Preliminary results of all‐atom molecular dynamics simulations agree with experiment. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electric transport properties and 1H NMR study of the fullerene‐like WS2 nanoparticles
Authors: Kopnov Frieda , Leitus Gregory , Yoffe Alex , Feldman Isai , Panich A. M. , Tenne Reshef
Published: September 2006

Electrical resistivity and Hall measurements, of pellets compacted from IF ‐WS2 nanoparticles and 2H‐WS2 powder were done. Electrical transport measurements were carried out on pellets by the van der Pauw method in a wide temperature range. Arrhenius plots for conductivities of the WS2 samples (2H, IF and IF +treatment) exhibit marked variations in (∂ ln σT –1)/∂T –1 with temperature. Resistivity of IF ‐WS2 pellets is higher than that of 2H‐WS2 pellets. It was found that the electrical properties of IF ‐WS2 powder vary with aposteriory heat treatment under vacuum. The 1H NMR measurements show that the prepared product contains water (and possibly some hydrogen) molecules that occupy the voids in the central part of the fullerene‐like nanoparticles and the nanopores between the adhering IF ‐WS2 particles. Defects in the IF ‐WS2 structure, arising due to the strain release during the folding of the layers, may result in additional sites for the absorbed water. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polymer ring formation by electron/hole injection from an STM tip into a C60 close‐packed layer
Authors: Nouchi Ryo , Masunari Kosuke , Ohta Toshio , Kubozono Yoshihiro , Iwasa Yoshihiro
Published: September 2006

Polymerization and depolymerization of C60 molecules are induced by charge carrier injection from a scanning tunneling microscope tip into C60 close‐packed layers. These reactions are hard to be achieved at single molecular precision because of a spatial spread of injected carriers. We report that the carrier‐spreading effect produces a ring‐shaped distribution of C60 polymers around the carrier injection point. Formation of the polymer ring of C60 is explained by energy dissipation of spreading carriers. Therefore, the polymer ring can be recognized as a direct reflection of carrier propagation. Subsequent electron or hole injections enlarge the ring. This result shows that both electrons and holes can induce both polymerization and depolymerization of C60 molecules. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
PL, magneto‐PL and PLE of the trimetallic nitride template fullerene Er3N@C80
Authors: Jones Mark A. G. , Morton John J. L. , Taylor Robert A. , Ardavan Arzhang , Briggs G. Andrew D.
Published: September 2006

Er3N@C80 exhibits sharp optical emission lines in the near‐infrared attributed to fluorescence from the Er3+ ion. Here we demonstrate that high magnetic fields cause this spectrum to split, corresponding to transitions from the lowest field‐split Kramers doublet of the 4I13/2 manifold to the four lowest field‐split levels of the 4I15/2 manifold. The internal structure of these fullerenes can be spatially aligned with a preferred orientation under high magnetic field; the effect of alignment is to reduce the broadening associated with the isotropic spatial averaging characteristic of powder or frozen‐solution spectra. Using a tunable 1.5 μm laser, we directly observe non‐cage‐mediated optical interactions with the Er3+ ion. This spectroscopic method provides the opportunity to map the energy level structure of the incarcerated ion and to coherently control its quantum state. These qualities suggest that rare‐earth endohedral fullerenes have characteristics that could be employed as a readout pathway for fullerene‐based quantum information processing. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Li doped Mo6S6 nanowires: elastic and electronic properties
Authors: Gemming S. , Seifert G. , Vilfan I.
Published: September 2006

Isolated and crystalline Mo6S6 nanowires, doped with Li to form Li2Mo6S6, are investigated with the density‐functional techniques. We find that Li atoms “decorate” individual wires at the S‐coordinated sites and occupy the interstitial positions between 3 S atoms in crystalline nanowires. Doping with Li changes the lattice constants by less than 0.1 Å, but it decreases the modulus of elasticity along the wire axis in the crystalline form. Doping raises the Fermi energy but retains the strongly uniaxial metallic character of nanowires, attributed to the Mo(4d) electrons. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A method for enhanced analysis of specific as‐grown carbon nanotubes
Authors: Jungen Alain , Stampfer Christoph , Durrer Lukas , Helbling Thomas , Hierold Christofer
Published: September 2006

We present the design of a microsystem along with a series of process steps to integrate carbon nanotubes in a scalable way that allows them for analysis in various experimental equipments. The microsystems consist of drilled thin silicon layers on top of a substrate which accommodate the nanostructures by chemical vapor deposition (CVD) directly within their drills. These layers can then be manipulated in a way that enables the usage of laboratory apparatus requiring substrate‐less samples like transmission electron microscopy. Scanning electron microscopy is used as an analysis tool to identify the presence and location relative to the microsystem structure. Raman microscopy is used subsequently to confirm the detection and location of the nanostructures and to gain insights into their structural properties. The suggested technique is compatible with various CVD'ed nanowires or nanofibers. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
N@C60 and N@C70 oriented in a single‐crystalline matrix
Authors: Naydenov B. , Spudat Ch. , Scheloske M. , Suess H. I. , Hulliger J. , Harneit W.
Published: September 2006

We report the encapsulation of N@C60 and N@C70 in a solid state matrix consisting of 2,4,6‐tris‐(4‐bromophenoxy)‐1,3,5‐triazine (BrPOT). Two different crystal structures were observed – hexagonal and rhombohedral. The carbon cage of the fullerenes is distorted, leading to zero field splitting (ZFS) of the quartet electronic ground state of the nitrogen atom, which depends on the crystal structure and on the solvent used in the crystallization process. N@C60 hexagonal crystals show no ZFS when they are obtained from toluene solution and a small ZFS in the case of CS2, while rhombohedral crystals show sizeable ZFS but they were found only in the toluene samples. N@C70 incorporates only in hexagonal crystals with small ZFS in the case of CS2. For toluene the ZFS is observed only at temperatures lower than 150 K. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Near‐field imaging and spectroscopy of electronic states in single‐walled carbon nanotubes
Authors: Qian Huihong , Gokus Tobias , Anderson Neil , Novotny Lukas , Meixner Alfred J. , Hartschuh Achim
Published: September 2006

Near‐field photoluminescence spectroscopy was used to study the electronic properties of semiconducting Single‐Walled Carbon Nanotubes in different environments. A sharp laser‐illuminated metal tip was raster scanned over the sample and served as a strongly confined excitation source. We observed localization of photoluminescence and variations of emission energies along nanotubes on a length scale of about 30 nm. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Agent‐based modeling for investigating adaptivity of misperception
Authors: Akaishi Jin , Arita Takaya
Published: September 2006

Misperception is a term which is generally used in a negative sense. However, when information promoting a certain kind of behavior is obtained, it can happen that the diversity of the behavior is enhanced by the misperceptions of the individual in the population, resulting in a situation in which misperception works advantageously for the population. This paper presents this view in terms of four hypotheses, dealing with (1) the basic adaptivity of misperception, (2) basic properties of communication, (3) the adaptivity of misperception in communication, and (4) the behavioral specificity of information in the adaptivity of misperception. A simple agent model for the resource‐searching problem is constructed. Direct misperception, which is misperception in the direct acquisition of information from the surrounding environment, and indirect misperception, which occurs when information is obtained through communication, are considered. Their effects are investigated by simulation experiments. It is shown that misperception enhances the diversity of agent behavior and can contribute to adaptivity. It is also shown that exact communication may decrease the diversity of agent behavior, and that adaptivity is decreased when false information is shared. A tendency for the adaptivity of misperception to decrease when the behavioral specificity in information terms is low is demonstrated. We believe that study of the adaptivity of misperception as a factor generating diversity will lead to new findings in cognitive science, memetics, and fundamental aspects of engineering. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(12): 96–106, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20266
Human tracking using the temporally averaged silhouette with an active camera
Authors: Haga Tetsuji , Sumi Kazuhiko , Yagi Yasushi
Published: September 2006

This research paper proposes an image processing algorithm for tracking nonrigid moving objects such as humans in outdoor locations. Since the camera itself moves, it is believed that an effective method extracts and tracks the movement object by using the differences in the flow against the background, rather than by using intensity‐based background subtraction. However, since nonrigid objects are tracked outdoors, the flow is partially lost due to variation in the shape and aspect, occlusion due to obstacles, passage through high‐contrast backgrounds, and other factors, so the tracking center of gravity is not stable, and tracking is often lost. In view of the above, tracking is carried out in the proposed method by using areas referred to as “temporally averaged silhouettes,” which are obtained by accumulating small areas extracted by the difference between the background and the flow while positioning the small areas in pixel units across a number of frames. Since the flow is observed over a long period of time instead of carrying out detailed spatial calculations, the area of the moving object can be stably calculated even if the flow partially disappears, so computational efficiency is good. The results of experiments using scenes with humans in motion confirm that stable tracking results that are equivalent to or better than cases in which the flow is calculated for the entire image (about 1200 points) are obtained by using a flow with a small number of points (average: 64 points) in the combined moving‐object and background areas. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(12): 69–81, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20490
Generating head–eye movement for virtual actor
Authors: Masuko Soh , Hoshino Junichi
Published: September 2006

Multimedia content such as videos and games often includes animation, in which virtual actors engage in conversations. In constructing such an animation, there are many factors to be considered, such as the content of the utterance and the state of conversation, which necessitates a large amount of time and labor. To deal with this problem, this paper presents a method by which the head and eye movements of the virtual actor can be generated in a simple way, synchronized with the conversation. In this method, the view line angle is defined as the sum of the head and eye rotations. A shared motion mechanism is considered in which the ratio of the head and eye rotations is dynamically adjusted according to the view line direction, so that a composite movement of the head and eyes is generated. Letting the two modules generating the head and the eye movements share the same conversation state, head and eye movements synchronized with the conversation are generated. Finally, the proposed method is applied, and the animation of a virtual actor synchronized with the conversation is demonstrated. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(12): 33–44, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20513
Recognizing article errors using prepositional information
Authors: Nagata Ryo , Iguchi Tatsuya , Wakidera Kenta , Masui Fumito , Kawai Atsuo , Isu Naoki
Published: September 2006

In this paper, we propose a prepositional model that uses prepositional information to detect article errors often seen in English sentences written by Japanese learners of English. The conventional methods for detecting article errors include a statistical model that is based on statistics obtained from an electronic corpus created from documents such as English newspapers. However, the usage of the articles has many exceptions, and thus the performance of the statistical model is not yet sufficient. Hence, in the prepositional model, the performance of the statistical model is improved by using prepositional information, and errors are detected while also taking into account exceptional usages of the articles. In an experiment, it was verified that the performance of the prepositional model (F−measure = 0.72) is a huge improvement over the performance of the statistical model (F−measure = 0.53) in dealing with article errors in prepositional phrases. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(12): 17–26, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20527
The massive sulphide event in the Iberian Pyrite Belt: confirmatory evidence from the Sotiel-Coronada Mine
Authors: GONZÁLEZ FELIPE , MORENO CARMEN , SANTOS AMÉRICO
Published: September 2006

Well-preserved miospore and organic-walled microphytoplankton assemblages have been recovered from the black shaly series hosting the massive sulphide deposits of Sotiel-Coronada Mine (Iberian Pyrite Belt). The productive samples yielded miospore assemblages representing the uppermost Famennian Retispora lepidophyta–Verrucosisporites nitidus (LN) miospore Biozone of Western Europe. This palynological evidence has important implications for the local geology, constraining the commencement of the volcanic activity and corroborating the previously-defined local tectonic style. Moreover, at regional scale, the new data permit correlation of the black shaly series (which hosts the mineralization in all the sulphide deposits hitherto dated in the region), reinforcing the hypothesis of an anoxic event occurring in the Iberian Pyrite Belt in the latest Devonian times.
Collection and marketing of non-timber forest products in the far western hills of Nepal
Authors: BISTA SAGUN , WEBB EDWARD L.
Published: September 2006

Non–timber forest product (NTFP) use is an integral part of the rural economy of Nepal, but little is known about NTFP collection and marketing dynamics. This study investigated the intensity of NTFP collection, the financial benefits gained through the collection of a representative species, and the contextual factors influencing NTFP collection and sale in 12 villages of the Baitadi district of far western Nepal. Thirty-nine per cent of the economically active population collected a total of 24 NTFPs from 23 species, which contributed 0–90% of the total household income. A marketing chain and financial analysis of Valeriana jatamansi (sugandhwal) revealed that various trading and marketing channels existed from the village to district-level NTFP outlets. The price received by the collector depended on the length of the market chain and the political context of the market. Political instability resulting from the Maoist insurgency reduced profits from sugandhwal sale by 23–25%. The number of NTFP-selling outlets accessed by collectors was the most important variable determining the number of NTFPs collected and the overall contribution of NTFPs to the household. Physical accessibility of the village did not impact the contribution of NTFPs to the household livelihood. The strength of NTFP-related institutions (both government and non-governmental organizations) decreased the total NTFP contribution to livelihoods because at the time of the study the villages were in transition to domestication of NTFPs. In the future, the contribution of domesticated NTFPs to households in villages with strong NTFP-related institutions should be much greater than at present. Increasing access to NTFP-selling outlets may be achieved through information dissemination, empowerment of collectors and establishment of linkages between collectors and traders. In general, domestication is an important strategy to ensure a continuous supply of NTFPs. Middlemen traders are seen as important stabilizers of prices as long as fair trading practices are followed. Monitoring of these villages over time will also provide important new quantitative information on the process of transition in rural villages changing from a forest-collection NTFP procurement strategy to a domestication procurement strategy.
Toward an optimal approach for health and transportation
Authors: HIGGINS PAUL A.T.
Published: September 2006

Pretty (2006) offered a valuable perspective on the psychological benefits of exercise in green environments. This makes intuitive sense, for who among us does not recognize the personal benefits we receive from being active and surrounded by nature's beauty? The quantitative support that Pretty (2006) offered confirms this anecdotal experience, and provides an extremely valuable contribution to the debate.
Tree density, basal area and species diversity in a disturbed dry tropical forest of northern India: implications for conservation
Authors: SAGAR R. , SINGH J.S.
Published: September 2006

Dry tropical forest communities are among the world's most threatened systems and urgent measures are required to protect and restore them in degraded landscapes. For planning conservation strategies, there is a need to determine the few essential measurable properties, such as number of species and basal area, that best describe the dry forest vegetation and its environment, and to document quantitative relationships among them. This paper examines the relationships between forest basal area and diversity components (number of species and evenness) for a disturbed dry tropical forest of northern India. Data were collected from five sites located in the Vindhyan dry tropical forest of India, selected on the basis of satellite images and field observations to represent the entire range of conditions in terms of canopy cover and disturbance regimes. These sites represented different communities in terms of species composition. The forest was poorer in species richness, and lower in stem density and basal area than wet forests of the tropics. Across sites (communities), the diversity components and tree density were positively related with total tree basal area. Considering basal area as a surrogate of biomass and net production, diversity is found to be positively associated with productivity. A positive relationship between basal area, tree density and species diversity may be an important characteristic of the dry forest, where recurring disturbance does not permit concentration of biomass or stems in only a few strong competitors. However, the relationships of basal area with density, alpha diversity and evenness remain statistically significant only when data from all sites, including the extremely disturbed one, are used in the analysis. In some sites there was a greater coefficient of variation (CV) of basal area than in others, attributed to patchy distribution of stems and resultant blanks. Therefore, to enhance the tree diversity of these forests, the variability in tree basal area must be reduced by regulating local disturbances. Conservation activities, particularly fuelwood plantations near human settlements, deferred grazing and canopy enrichment through multi-species plantations of nursery-raised or wild-collected seedlings of desirable species within the forest patches of low basal area, will be needed to attain restoration goals, but reforestation programmes will have to be made attractive to the forest-dwelling communities.
Achtsamkeit und Akzeptanz in der Psychotherapie
Authors: Michalak Johannes , Heidenreich Thomas , Bohus Martin
Published: September 2006

Es wird ein Überblick zum Forschungsstand und zu Forschungsentwicklungen im Bereich achtsamkeits- und akzeptanzbasierter Ansätze gegeben. Dabei werden drei Forschungsstränge beschrieben: (1) Wirksamkeitsuntersuchungen zur “Mindfulness-Based Stress Reduction” (MBSR), zur “Mindfulness-Based Cognitive Therapy” (MBCT), zur “Dialektisch-Behavioralen Therapie bei Borderlinestörungen” (DBT) und zur “Acceptance and Commitment Therapy” (ACT); (2) Psychometrische Verfahren zur empirischen Erfassung von Achtsamkeit; (3) Untersuchungen aus dem Bereich der psychologischen Grundlagenforschung und neurobiologische Arbeiten. Der Artikel schließt mit einer Diskussion der Besonderheiten einer wissenschaftlichen Analyse von Achtsamkeit und Akzeptanz und einem Forschungsausblick.
Wirkmechanismen achtsamkeitsbasierter Psychotherapie
Authors: Bohus Martin , Huppertz Michael
Published: September 2006

Spätestens seit der Veröffentlichung randomisiert kontrollierter Studien zur Wirksamkeit von “Mindfulness-Based Cognitive Therapy” bei der Rückfallprophylaxe depressiver Episoden haben achtsamkeitsbasierte Therapien auch akademisches und wissenschaftliches Interesse geweckt. Untersuchungen zur Wirkweise dieser Verfahren stehen jedoch noch ganz am Anfang. Zunächst wird das Problem der Integration von akzeptanzbasierten Methoden und therapeutisch intendierter Veränderung von Verhalten oder Erleben im historischen Kontext ausgelotet. In einem zweiten Schritt werden Hypothesen zu therapeutischen Mechanismen der Achtsamkeit im kognitiv-behavioralen Kontext formuliert: a) Aktivierung von metakognitiven Ebenen; b) Annahme und Akzeptanz als Grundlagen der Selbstinstruktion; und c) Verbesserung der Emotionsfokussierung während expositionsbasierter Verfahren.
Diurnal variations of temperature and winds inferred from TIMED and UARS measurements
Authors: Huang Frank T. , Mayr Hans G. , Reber Carl A. , Killeen Timothy , Russell James , Mlynczak Marty , Skinner Wilbert , Mengel John
Published: September 2006

Owing to their sampling properties in local solar time, both the TIMED and UARS spacecrafts provide the opportunity to quantitatively study the mesospheric thermal tides. The information though is limited because it takes the TIMED instruments 2 months to cover the full range of 24 hours, almost twice as long as UARS. We present here the results of an analysis, in which the seasonal and global‐scale variations of amplitude and phase for the migrating diurnal tide are retrieved from atmospheric temperature and wind measurements on the TIMED (SABER, TIDI) and UARS (MLS, HRDI) satellites. Comparisons are made with results from the Numerical Spectral Model (NSM), which is characterized in part by the parameterization of small‐scale gravity waves. At 60 km and above, the amplitude and phase variations of the diurnal tide from the NSM agree generally well with those derived from the SABER temperatures. In the SABER temperature amplitudes at around 60 km there are evident asymmetries in latitude with respect to the equator, which are not apparent in the MLS data near 55 km or in the NSM. (The asymmetry in the SABER temperatures disappears above 60 km.) For the meridional winds of the migrating diurnal tide derived from TIDI, the phase and relative amplitude variation with latitude and season are in qualitative agreement with the HRDI measurements and the NSM. The amplitudes from TIDI winds are systematically smaller, but this may in part be due to interannual variations. However, the results for the zonal winds from TIDI more often do not agree well with those from HRDI or the NSM.
LF/MF Whistler mode dispersive signals observed with rocket‐borne instruments in the auroral downward current region
Authors: Samara M. , LaBelle J.
Published: September 2006

The SIERRA sounding rocket launched 14 January 2002, northward from Poker Flat, Alaska, to an altitude of 735 km in active aurora. On the downleg, in the altitude range 500–700 km, the onboard high‐frequency wave experiment detected structured whistler mode signals in the frequency range 100–1000 kHz, lasting nearly 200 s during which the rocket moved approximately 200 km downrange. The most prominent feature consisted of narrowband signals with frequency descending from 500 kHz to 250 kHz in about 0.5 s, with bandwidths ∼10 kHz, with frequency spacings ∼25 kHz, and with amplitudes in the range 10–400 μV/m. The structured whistler mode signals coincide with a region of Alfvénically accelerated electrons of the type often associated with the downward current region, poleward of the inverted‐V electron structures usually associated with the upward current region. However, on short timescales there was no clear correlation between the whistler mode signals and the locally detected electron flux or density. Ray‐tracing calculations indicate that concentrated sources of waves originating on the whistler mode resonance cone and moving upward through a model ionosphere, with speeds of 1000–5000 km/s, to rocket altitudes, exhibit the magnitude of dispersion of the observed structured whistler mode features. We evaluate the strengths and weaknesses of the hypothesis that these concentrated sources could be associated with phase space electron holes shedding electrostatic whistlers as they move upward along the field line at altitudes much higher than the rocket in the downward current region.
Assimilating long‐term hydrographic information into an eddy‐permitting model of the North Atlantic
Authors: Wright D. G. , Thompson K. R. , Lu Y.
Published: September 2006

The utility of a new technique for assimilating long‐term hydrographic information into eddy‐permitting ocean models is demonstrated using the Parallel Ocean Program (POP) applied to the North Atlantic. Robust diagnostic and standard prognostic simulations of the North Atlantic yield results similar to those obtained in earlier studies and the differences between them emphasize the need for data assimilation. The basic idea of the new technique is to add correction terms to the model equations that directly influence the model solution only in prescribed frequency and wave number bands, leaving the variations outside of these bands free to evolve prognostically. For this reason the technique is referred to as spectral nudging. We consider two approaches for constraining eddy‐permitting models based on observed long‐term hydrographic conditions. In the first approach, the model's temperature and salinity climatologies are spectrally nudged toward observed values using restoring terms in the tracer equations; in the second, correction terms are added to the momentum equations. Both approaches result in significant improvements in the model's climatology, as expected. Both approaches also result in more realistic meso‐scale eddy fields. However, for the simulations considered here, spectral nudging in the tracer equations generally provides better results than nudging in the momentum equations. An examination of the relationship between the two approaches reveals that this result might be expected to also occur in other model simulations but this is achieved at the cost of increased constraints placed on model dynamics within the nudged frequency and wave number bands.
Validation of nighttime UV measurements of the F region ionosphere made by the low resolution airglow and aurora spectrograph (LORAAS) instrument
Authors: Coker Clayton , Bennert Ellen , Dymond K. F.
Published: September 2006

We present electron density profiles derived by inversion of ultraviolet limb radiances observed during November 2000 through April 2001 by the low resolution airglow and aurora spectrograph (LORAAS) instrument on the Advanced Research and Global Observing Satellite (ARGOS). The O+ density profile, which is approximately equal to the electron density profile in the F region ionosphere, was determined by inverting the limb radiance profile of O I 1356 Å emission of atomic oxygen; the 1356 Å emission is produced purely by radiative recombination of O+ ions and electrons at night and has been shown to be a viable means of globally sensing the ionospheric state. Dymond et al. (2001b) showed a preliminary validation of this technique covering a single day of observations. We have performed a more extended validation of the retrieved peak electron density and peak height determined by inversion of nighttime observations of the 1356 Å altitude profiles with coincident ionosonde measurements and climatology.