bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved two‐dimensional J‐resolved spectroscopy
Authors: Schulte Rolf F. , Lange Thomas , Beck Johannes , Meier Dieter , Boesiger Peter
Published: March 2006

Localised two‐dimensional J‐resolved spectroscopy (JPRESS) is optimised for the in vivo detection of J‐coupled metabolites using magnetic resonance spectroscopy at 3 T. The acquisition of echo signals starts as early as possible (i.e. maximum‐echo sampling). This sampling scheme increases sensitivity and decreases overlap of peak tails, hence alleviating baseline problems. Reconstruction issues are discussed and the sensitivity is compared analytically with that of 1D PRESS. The qualitative behaviour of eddy currents in JPRESS is outlined and a 2D eddy current correction procedure based on the 1D phase deconvolution method is proposed. Copyright © 2006 John Wiley & Sons, Ltd.
Primary malignant peripheral nerve sheath tumor of the lung in a young child without neurofibromatosis type 1
Authors: Muwakkit Samar A. , Rodriguez‐Galindo Carlos , EL Samra Ahmad I. , Khoury Ruby , Akel Samir R. , Mroueh Salman , Razzouk Bassem , Abboud Miguel R.
Published: March 2006

Malignant peripheral nerve sheath tumors (MPNST) are uncommon in children and almost half of the cases occur in patients with neurofibromatosis 1 (NF1). We report a child with a primary MPNST of the lung without NF1. MPNST of the lung has similar clinical and radiologic characteristics as pleuropulmonary blastoma. We suggest to include MPNST of the lung in the differential diagnosis of intrapulmonary masses in children. Pediatr Blood Cancer 2006; 47:636–638. © 2006 Wiley‐Liss, Inc.
Thyroid abnormalities in infantile hepatic hemangioendothelioma
Authors: Kalpatthi Ram , Germak John , Mizelle Katherine , Yeager Nicholas
Published: March 2006

We report an infant with hepatic hemangioendothelioma (HAE) associated with compensated hypothyroidism. The hepatic lesions regressed with steroid therapy and his thyroid function normalized with high doses of thyroxine supplement. Pediatr Blood Cancer 2007;49:1021–1024. © 2006 Wiley‐Liss, Inc.
Substructural cooperativity and parallel versus sequential events during protein unfolding
Authors: Reich Lothar , Weikl Thomas R.
Published: March 2006

According to the “old view,” proteins fold along well‐defined sequential pathways, whereas the “new view” sees protein folding as a highly parallel stochastic process on funnel‐shaped energy landscapes. We have analyzed parallel and sequential processes on a large number of molecular dynamics unfolding trajectories of the protein CI2 at high temperatures. Using rigorous statistical measures, we quantify the degree of sequentiality on two structural levels. The unfolding process is highly parallel on the microstructural level of individual contacts. On a coarser, macrostructural level of contact clusters, characteristic parallel and sequential events emerge. These characteristic events can be understood from loop‐closure dependencies between the contact clusters. A correlation analysis of the unfolding times of the contacts reveals a high degree of substructural cooperativity within the contact clusters. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Transport properties of fullerene‐like WS2 nanoparticles
Authors: Kopnov F. , Yoffe A. , Leitus G. , Tenne R.
Published: March 2006

Electrical resistivity and Hall effect measurements of pellets compacted from fullerene‐like WS2 nanoparticles (IF ‐WS2) and bulk 2H‐WS2 powder were carried out using the van der Pauw method over a wide temperature range. In addition IF ‐WS2 pellets were annealed at elevated temperatures under vacuum in a specially designed system. Arrhenius plots for the conductivities of the WS2 samples (2H, IF and IF +annealing) exhibit marked uprise of ∂ ln (sT –1)/∂T –1 with temperature. The resistivity of the non‐annealed IF ‐WS2 pellets is higher by 2–8 orders of magnitude than that of 2H‐WS2 pellets, whereas the resistivity of the annealed IF pellets is higher than that of the non‐annealed ones. Hall Effect measurements at 300 K show p‐type conductivity and similar carrier concentration for both types of materials. The carrier mobility of 2H‐WS2 platelets is found to be in the range of the reported values. However, IF ‐WS2 pellets have shown an unusually low mobility for a semiconducting material. The experimental data was found to be in a good agreement with a model used for analyzing the conductivity of polycrystalline semiconductors, which takes into consideration fluctuations of the barrier heights among the different nanoparticles as well as within a single nanoparticle boundary. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical simulation of inhomogeneous and nonlinear diffusion
Authors: Sharma Anurag , Shishodia Manmohan Singh , Reddy G. B.
Published: March 2006

A numerical technique, based on the collocation method, for solving the diffusion equation is presented. The method is applicable to general problem of diffusion including the cases where the diffusion properties are inhomogeneous and time dependent. It is also applicable to the problem of nonlinear diffusion where the diffusion coefficient is dependent on the concentration of the diffusants. Examples to show the applicability and computational efficiency of the method have also been included. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A study of the ferromagnetic behavior of Nd16Co76–xRuxB8 alloys
Authors: Paduani C. , Valcanover J. A. , Ardisson J. D. , Yoshida M. I.
Published: March 2006

The structural and magnetic properties of the tetragonal 2:14:1 hard magnetic phase (ϕ ) were investigated in Nd16Co76–x Rux B8 alloys. The results indicated that Ru substitution does not harm the formation of ϕ in Co‐rich alloys. An antiferromagnetic Co–Ru coupling is concluded. The cell volume initially decreases with the Ru substitution. The coercivity is enhanced and reaches a maximum at the composition where the saturation magnetization has the lowest value. The Curie temperature as well as the mean magnetic moment decrease with increasing Ru concentration. With the increase of the Ru concentration the unit‐cell volume increases. A ferrimagnetic ordering is predicted at higher Ru concentrations. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Some electronic and optical properties of self‐assembled quantum dots: asymmetries in a lens domain
Authors: Rodríguez A. H. , Meza‐Montes L.
Published: March 2006

The self‐assembled quantum dot with lens domain has rotational symmetry but it is intrinsically asymmetric when the electron moves perpendicularly to its circular base, i.e. along the rotational axis. To characterize this asymmetry, an external electric field is applied along either the positive or negative direction of the rotational axis. We report the different Stark shifts appearing in the spectra as a function of the field intensity for different lens domains. It is shown that for a flat lens domain the asymmetry effects decrease, but even for very flat lenses they can not be approximated by a cylindrical domain. Finally, some optical properties such as the dielectric constant and electroabsorption are studied. Signatures of the energy spectrum reveal in these quantities. The importance of considering the proper lens domain as long as the magnitude and direction field to tune a specific level transition is stressed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Acoustic phonon power spectra in a periodic superlattice
Authors: Mauriz P. W. , Vasconcelos M. S. , Albuquerque E. L.
Published: March 2006

We consider a Green function formalism, based on the frequency distribution, to study the propagation of acoustic phonon modes in a periodic superlattice. The calculations are based on the linear response function approach, which is very convenient to deal with this kind of problem. A damping term γ is included in a phenomenological way into the wavevector expression. In order to examine the phonon excitation, we also determine, by using the fluctuation‐dissipation theorem, their power spectra, which have many interesting properties. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoelectrical and noise processes in CdTe crystals
Authors: Virt I. S. , Bilyk I. S. , Popovych V. D. , Rudyj I. O. , Kurilo I. V. , Kolek A. , Bester M. , Kuzma M.
Published: March 2006

Two types of cadmium telluride single crystals were investigated: undoped CdTe grown by Bridgeman method and highly doped CdTe:Cl obtained by STHM. Photoconductivity properties of CdTe crystals were studied by the transient photoconductivity method. Persistent photo response due to the polarization effect was revealed in undoped samples. Noise spectra have been measured over a wide range of frequencies, from below 1 Hz up to 1 MHz, and for voltages applied the samples from 0 up to 200 V. Two type of noise dominates in the range of voltages and frequencies under investigation, namely excess 1/f noise and generation‐recombination (G‐R) noise. Two‐phase model were applied to explain noise experimental results, which consider the presence of precipitates. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Luminescent properties of ZnS:Ce,Y phosphor
Authors: Okamoto Shinji , Tanaka Katsu
Published: March 2006

The ZnS:Ce phosphor together with a co‐activator Y3+ ion shows a bright saturated blue luminescence whose spectrum is a band with a peak wavelength of 450 nm. The chromaticity coordinates are x = 0.15 and y = 0.09, and thus this phosphor would be good for the blue primary color in displays and light sources. The blue luminescence is due to the 5d‐4f internal transition of the Ce3+ ion. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exciton‐donor complexes in a semiconductor quantum dot in a magnetic field
Authors: Djotyan A. P. , Avetisyan A. A. , Kazaryan E. M. , Moulopoulos K.
Published: March 2006

The binding energy of the ground state of a charged exciton‐donor complex in a spherical semiconductor quantum dot in the presence of a homogeneous magnetic field has been calculated. The theoretical analysis is carried out using a variational approach in the framework of the adiabatic approximation. The behavior of the binding energy of the complex in a QD on magnetic field is investigated for different values of the QD radius. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of annealing on the structural and magnetic properties of epitaxial Zn1–xMnxO films grown by MOCVD on sapphire
Authors: Chikoidze E. , von Bardeleben H. J. , Dumont Y. , Jomard F. , Gorochov O.
Published: March 2006

Thermal annealing of MOCVD grown Zn1–xMnxO layers between 300 °C and 1000 °C in an oxygen atmosphere modifies both their latttice parameters and their magnetic properties. Combined X‐ray diffraction and EPR studies indicate a redistribution of intrinsic defects but persistent antiferromagnetic phase in the annealed films. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evaluation of crystal structure and photoluminescence for ZnTe epilayers grown on a 2o off‐oriented GaAs (100) substrate
Authors: Yu Young‐Moon , Yoon M.‐Y. , Choi Yong Dae
Published: March 2006

High quality zincblende ZnTe epitaxial layers have been grown on a tilted GaAs (100) substrate by hot‐wall epitaxy. The surface morphology and the crystallinity were investigated in terms of their growth temperature dependence while the optical properties were analyzed by photoluminescence spectroscopy (PL). It was found that the orientation of the epitaxial layer was inclined to the substrate crystal plane. The optimum growth condition was found to be a growth temperature of 470 °C. The ground state and excited states of free exciton emissions were clearly observed at 10 K PL. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of GaN buffer layers on the polarity and properties of ZnO epilayers on nitrided c‐Al2O3 by MBE
Authors: Roh O. H. , Wang X. , Che S. B. , Ishitani Y. , Yoshikawa A.
Published: March 2006

ZnO epilayers were grown on nitrided c‐Al2O3 substrates by MBE and the effect of the deposition temperature for GaN buffer layers on the polarity of ZnO epilayer and their properties such as structural and optical properties were investigated. Zn‐polar ZnO was normally obtained by using the low temperature GaN buffer layer at 650 °C, while O‐polar ZnO were obtained by the high‐temperature GaN buffer layer at 850 °C. PL spectra for Zn‐polar and O‐polar ZnO epilayers, PL spectra were dominated by donor‐bound exciton at 3.361 eV and acceptor‐bound exciton at 3.356 eV, respectively. It was found that the position of emission peak was affected by the strain in the ZnO layer. PL spectra observed in ZnO epilayers with different polarities are discussed together with their reflectance spectra and strains of ZnO epilayers with different polarities. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of the ex‐situ and in‐situ annealed self‐buffer layer on ZnO film
Authors: Wang Jinzhong , Sallet Vincent , Amiri Gaëlle , Rommelluere Jean‐François , Lusson Alain , Rzepka E. , Lewis John E. , Galtier Pierre , Fortunato Elvira , Martins Rodrigo , Gorochov Ouri
Published: March 2006

Two self‐buffer layers were grown on c‐plane sapphire substrates by atmospheric MOCVD method using DEZn, tert‐butanol as precursors and H2 as carrier gas. Then, they were respectively annealed in growth process and oxygen environment. After that, ZnO films were respectively grown on them. XRD spectra show that all the films were grown in [002] orientation. Furthermore, the film with a buffer layer annealed in oxygen exhibits much higher crystal quality. Its FWHM of the rocking curve is only 567 arcsec. Furthermore, its Raman scattering spectrum appears a much stronger E2 mode peak at 436 cm–1 and its PL spectrum appears a shoulder at 3.367 eV on the higher energy side. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Oligomerization process in MOVPE growth of ZnO
Authors: Maejima K. , Fujita S.
Published: March 2006

Chemical reactions in the vapor phase during metalorganic vapor phase epitaxy growth of ZnO are investigated with in‐situ monitoring using Fourier transform infrared spectroscopy. Diethylzin (DEZn) and nitrous oxide (N2O) were used for zinc and oxygen source, respectively. DEZn reacts first with oxygen atom generated from N2O dissociation, and changes to diethoxy zinc (DEOZn; Zn(OC2H5)2). Then C2H4 is eliminated from DEOZn at high temperature, and DEOZn changes to zinc dihydroxide (Zn(OH)2). In addition to these reactions, oligomerization of the reactants occurs, that is, they make their dimers, trimers, tetramers and higher‐order oligomers, and they contribute to the formation of ZnO on the substrates. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetoresistance of n‐type ZnO:Al and Zn1–xMnxO:Al thin films
Authors: Andrearczyk T. , Jaroszyński J. , Grabecki G. , Dietl T. , Fukumura T. , Kawasaki M.
Published: March 2006

The role of spin‐orbit and s‐d exchange interactions is investigated by magnetoresistance (MR) measurements carried out down to 50 mK on ZnO and Zn1–x Mnx O with x = 3 and 7% and electron concentration ∼1020 cm–3. The data for ZnO:Al leads to the coupling constant λ so = (4.4 ± 0.4) × 10–11 eV cm of the kp hamiltonian for the wurzite structure, H so = λ soc(s × k). Complex MR of Zn1–x Mnx O:Al is interpreted in terms of the influence of the s‐d spin‐splitting on the disorder‐modified electron‐electron interactions and precursor effects of magnetism‐related localization. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigations of p‐type signal for ZnO thin films grown on (100) GaAs substrates by pulsed laser deposition
Authors: Rogers D. J. , Teherani F. Hosseini , Monteiro T. , Soares M. , Neves A. , Carmo M. , Pereira S. , Correia M. R. , Lusson A. , Alves E. , Barradas N. P. , Morrod J. K. , Prior K. A. , Kung P. , Yasan A. , Razeghi M.
Published: March 2006

In this work we investigated ZnO films grown on semi‐insulating (100) GaAs substrates by pulsed laser deposition. Samples were studied using techniques including X‐ray diffraction (XRD), scanning electron microscopy, atomic force microscopy, Raman spectroscopy, temperature dependent photoluminescence, C‐V profiling and temperature dependent Hall measurements. The Hall measurements showed a clear p‐type response with a relatively high mobility (∼260 cm2/V s) and a carrier concentration of ∼1.8 × 1019 cm–3. C‐V profiling confirmed a p‐type response. XRD and Raman spectroscopy indicated the presence of (0002) oriented wurtzite ZnO plus secondary phase(s) including (101) oriented Zn2As2O7. The results suggest that significant atomic mixing was occurring at the film/substrate interface for films grown at substrate temperatures of 450 ºC (without post‐annealing). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Catalyst‐free vapor‐phase transport growth of vertically aligned ZnO nanorods on 6H‐SiC and (11‐20)Al2O3
Authors: Mofor A. C. , Bakin A. S. , Elshaer A. , Fuhrmann D. , Bertram F. , Hangleiter A. , Christen J. , Waag A.
Published: March 2006

ZnO nanostructures are expected to pave the way for many interesting applications in optoelectronics, spin electronics gas sensor technology and biomedicine. Fabrication methods, especially for nanorods have been based mostly on catalyst‐assisted growth methods that employ metal‐organic sources and other contaminating agents like graphite to grow ZnO nanorods at relatively high temperatures. We report on the growth of ZnO nanorods on 6H‐SiC and (11‐20)Al2O3 using purely elemental sources, without catalysis and at relatively low temperatures and growth pressure in a specially designed vapor‐phase transport system. ZnO nanorods with widths of 80‐900 nm and lengths of 4–12 µm were obtained. Nanorod concentrations of up to 109 cm–2 with homogenous luminescence and high purity were noted. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Towards clean and atomically flat ZnO (000&1macr;) surfaces
Authors: Seldrum T. , Couet S. , Brison J. , Moisson C. , Turover D. , Sporken R. , Dumont J.
Published: March 2006

We established a cleaning procedure to obtain atomically flat $000 \bar {1}$ surfaces from pressurized melt grown ZnO using ex‐situ and in‐situ processing. The ex‐situ chemical cleaning consisted in removing the surface fluid layer and contaminants from the surface. The physical in‐situ procedure used sputtering‐annealing cycles to clean and reconstruct the surface. 3 key parameters were in‐situ investigated: the annealing time, the annealing temperature and the sputtering energy. Investigations were carried out by means of Low Energy Electron Diffraction (LEED), Auger Electron Spectroscopy (AES), X‐ray Photoemission Spectroscopy (XPS), Time of Flight of Secondary Ion Mass Spectrometry (ToF‐SIMS), Atomic Force Microscopy and Spectroscopy (AFM and AFS) and Scanning Tunnelling Microscopy (STM). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microwave‐Assisted Dimroth Rearrangement of Thiazines to Dihydropyrimidinethiones: Synthetic and Mechanistic Aspects
Authors: Glasnov Toma N. , Vugts Danielle J. , Koningstein Manoe M. , Desai Bimbisar , Fabian Walter M. F. , Orru Romano V. A. , Kappe C. Oliver
Published: March 2006

The Dimroth rearrangement of a set of substituted 2‐amino‐6H‐1,3‐thiazines into 3,4‐dihydropyrimidine‐2‐thiones was investigated. The rearrangements were carried out under microwave irradiation conditions in batch or continuous flow format, employing either toluene or 1‐methyl‐2‐pyrrolidone as solvent. Thiazines bearing an ester group at the C5 position rearranged at a considerably higher temperature than derivatives without substituents at this position into the corresponding pyrimidinethiones. This strictly thermal rearrangement was studied in detail using differential scanning calorimetry and density functional theory computational methods. The reaction pathway involves a zwitterionic intermediate.
New tools for phenotypic analysis in Candida albicans: the WAR1 gene confers resistance to sorbate
Authors: Lebel Karine , MacPherson Sarah , Turcotte Bernard
Published: March 2006

Availability of the complete sequence of the Candida albicans genome allows for global gene analysis. We designed a gene deletion method to facilitate such studies. First, we constructed C. albicans strains that are both Δura3 and Δtrp1. Second, we designed a system that relies on in vitro recombination, using the Gateway® technology, for efficient generation of deletion cassettes. They are generated in two steps: (a) upstream and downstream DNA fragments of the chromosomal region to be deleted are amplified by PCR and introduced into two separate entry vectors; (b) the second step involves a quadruple recombination event including the two entry vectors, a plasmid bearing a marker of interest and a destination vector, in order to generate a plasmid containing the deletion cassette. The deletion plasmid contains very rare restriction sites for convenient excision of the knockout cassette. Selection in C. albicans can be performed with one of the following markers: the C. albicans URA3 gene, a modified S. cerevisiae TRP1 gene or the mycophenolic acid resistance (MPAR) gene. Upon integration into the genome, these markers can be removed by the use of 5‐fluoroorotic acid (URA3), 5‐fluoroanthranilic acid (TRP1) or the FLP recombinase (MPAR). Using this approach, we show that removal of the C. albicans orf19.1035 gene results in sensitivity to the weak acid sorbate, while its overexpression increases resistance to this compound. We named it WAR1, in analogy to its S. cerevisiae orthologue. Copyright © 2006 John Wiley & Sons, Ltd.
The relative merits of the tetO2 and tetO7 promoter systems for the functional analysis of heterologous genes in yeast and a compilation of essential yeast genes with tetO2 promoter substitutions
Authors: Wishart Jill A. , Osborn Michael , Gent Manda E. , Yen Kuangyu , Vujovic Zorana , Gitsham Paul , Zhang Nianshu , Ross Miller J. , Oliver Stephen G.
Published: March 2006

We have generated a collection of yeast strains, each of which has an essential yeast gene under the control of the tetracycline‐responsive, tetO, promoter. Screens using first‐generation promoter‐swap strains uncovered the non‐specific responsiveness of the tetO7 promoter to a known human transcription factor (hIRF‐1). Non‐specific regulation was not observed with the tetO2 promoter. Reporter assays have been used to demonstrate this phenomenon. Subsequent efforts to generate a collection of tetracycline‐regulatable strains have focused on the tetO2 promoter. These strains are available to the yeast community and can be used for functional genomics studies. Copyright © 2006 John Wiley & Sons, Ltd.
The more the merrier: comparative analysis of microarray studies on cell cycle‐regulated genes in fission yeast
Authors: Marguerat Samuel , Jensen Thomas S. , de Lichtenberg Ulrik , Wilhelm Brian T. , Jensen Lars J. , Bähler Jürg
Published: March 2006

The last two years have seen the publication of three genome‐wide gene expression studies of the fission yeast cell cycle. While these microarray papers largely agree on the main patterns of cell cycle‐regulated transcription and its control, there are discrepancies with regard to the identity and numbers of periodically expressed genes. We present benchmark and reproducibility analyses showing that the main discrepancies do not reflect differences in the data themselves (microarray or synchronization methods seem to lead only to minor biases) but rather in the interpretation of the data. Our reanalysis of the three datasets reveals that combining all independent information leads to an improved identification of periodically expressed genes. These evaluations suggest that the available microarray data do not allow reliable identification of more than about 500 cell cycle‐regulated genes. The temporal expression pattern of the top 500 periodically expressed genes is generally consistent across experiments and the three studies, together with our integrated analysis, provide a coherent and rich source of information on cell cycle‐regulated gene expression in Schizosaccharomyces pombe. The reanalysed datasets and other supplementary information are available from an accompanying website: http://www.cbs.dtu.dk/cellcycle/. We hope that this paper will resolve the apparent discrepancies between the previous studies and be useful both for wet‐lab biologists and for theoretical scientists who wish to take advantage of the data for follow‐up work. Copyright © 2006 John Wiley & Sons, Ltd.
Isolation and bioenergetic characterization of mitochondria from Pichia pastoris
Authors: Mar González‐Barroso M. , Ledesma Amalia , Lepper Simone , Pérez‐Magán Elisa , Zaragoza Pilar , Rial Eduardo
Published: March 2006

Pichia pastoris is a methylotrophic yeast of high biotechnological interest. The bioenergetic properties of mitochondria from Pichia pastoris have not yet been determined. We report on a protocol for the isolation of the mitochondria in a state that shows good energy coupling. Analysis of Pichia pastoris growth and bioenergetic properties of the isolated mitochondria reveals that glycerol is the carbon source that yields the best results. Under our growth conditions, mitochondria oxidize external NADH but do not possess an alternative oxidase. Finally, Pichia pastoris mitochondria also lack the nucleotide‐stimulated uncoupling pathway previously identified in Saccharomyces cerevisiae. Copyright © 2006 John Wiley & Sons, Ltd.
Food habits of Sika deer on Mt. Goyo, northern Honshu
Authors: Takatsuki Seiki
Published: March 2006

The food habits of Sika deer (Cervus nippon) on Mt. Goyo, northern Honshu (the main island of Japan), were studied. Among 88 plant species found in surveys, 36 species (40.9%) were eaten by the deer. The percentage frequency of feeding (F) was highest for graminoids (59.6%), followed by browses (16.6%) and ferns (7.7%) and lowest for forbs (5.4%). Though various kinds of plants were eaten, only limited species formed the bulk of the deer dietary composition. Sasa nipponica, in particular, was the most important constituent, ranking highest in F value (80.3%) and being the dominant component of feces. Fecal analyses revealed that, 1) in areas lower than 900 m in altitude, Sasa nipponica accounted for between 20 and 60% of the content and that pasture grasses were also important, and 2)S. nipponica occupied more than 50% in montane areas higher than 900 m, and even more than 80% in winter. The utilization of S. nipponica as a forage for Sika deer was discussed. This plant can be a key forage species because it meets all the necessary conditions: abundance and stability of supply, palatability, nutritive quality and tolerance to grazing.
Comparative ecophysiology of two representative Quercus species appearing in different stages of succession
Authors: Takenaka Akio
Published: March 2006

Ecophysiological comparisons were made of the growth and photosynthetic characteristics between seedlings of deciduous Quercus serrata and evergreen Quercus myrsinaefolia. Q. myrsinaefolia seedlings naturally occurring in secondary coppice forests showed exponential‐like growth in height with age, while sympatric Q. serrata seedlings were considerably smaller in height, their growth being limited by shortage of light. The photosynthetic characteristics measured under laboratory conditions showed no bases for the differences in growth between the two species on the forest floor: Light compensation points of the seedlings raised under 5% daylight were almost identical for the two species, being about 6.0 μE·m−2·s−1. Growth analysis of seedlings planted in a coppice forest showed that both Q. serrata and Q. myrsinaefolia could hardly grow during the summer under the shrub layer, when relative photon flux density (RPFD) was 0.9±0.5%. In the winter, when RPFD under the leafless canopy increased to 29.3±2.7%, the dry matter production of the evergreen seedlings of Q. myrsinaefolia was much improved. Current‐year seedlings of the species showed NAR of 0.102±0.021 g·dm−2·mo−1 during the winter. Temperature dependency of photosynthesis and increment of leaf temperature by direct solar beam also indicated active photosynthesis of Q. myrsinaefolia on the forest floor during the winter.
The seasonal abundance and vertical distribution of the <3‐μm phytoplakton in the north basin of Lake Biwa
Authors: Nagata Toshi
Published: March 2006

The seasonal changes in the size‐fractionated chlorophyll a concentrations (<3 μm, 3 to 25 μm, and >25 μm) were investigated at a pelagic site of the north basin of Lake Biwa during June to December 1985. Autofluorescing plankton cells in the <3‐μm fractions were also examined using the fluorescein isothiocyanate staining epifluorescence microscopic technique. The <3‐μm phytoplankton (usually dominated by chroococcoid cyanobacteria except for a few cases dominated by small eukaryotes) showed a clearly different pattern of seasonal change compared with the larger fractions. That is, from August to early September, chlorophyll a of the larger fractions declined considerably, while the <3‐μm chlorophyll a did not decrease significantly. Moreover, cyanobacterial cell density in the <3‐μm fraction showed a maximum value (2–3.5×105 cells·ml−1) during this period. The relative contribution of the <3‐μm chlorophyll a to the total chlorophyll a increased from <5% to 45% during the course of this change. No clear vertical trend in the distribution and composition of the <3‐μm phytoplankton was found, except that relatively large cyanobacteria (>4 μm3) appeared at a depth of 15m but not at 0,5 and 10 m from late July to August. These large cells were also found in November and December. The drastic seasonal change of phytoplankton size structure occurring in this basin was discussed in relation to grazing, nutrient depletion and sinking.
The spatial pattern and canopy‐understory association of trees in a cool temperate, mixed forest in western Japan
Authors: Akashi Nobuhiro
Published: March 2006

The spatial distribution pattern of trees and the association between canopy and understory individuals were examined with reference to the distribution of tree crowns in a cool temperate, mixed forest in Ohdaigahara, western Japan. Line transect and contact sampling methods were used to examine the pattern over various spatial scales. These methods are useful to detect patterns over a large study area. The dominance of Chamaecyparis obtusa on steep slopes forming large patches suggested that the distribution of this species is a consequence of landslides. Understory Fagus crenata showed a clumped distribution, and the relative coverage of this species was larger in canopy gaps than under a closed canopy. Understory individuals of Abies homolepis showed a positive association with canopy trees of F. crenata but a negative association with conspecific canopy individuals. These patterns suggested that F. crenata regenerates in canopy gaps and is replaced by A. homolepis. The dynamics of these two species are consistent with the process of gap dynamics. The effects of both small‐ and large‐scale disturbance must be evaluated to understand the mechanisms of patch formation and the coexistence of forest tree species.
Vegetation structure in relation to micro‐landform in an evergreen broad‐leaved forest on Amami Ohshima Island, south‐west Japan
Authors: Hara Masatoshi , Hirata Kazuhiro , Fujihara Michiro , Oono Keiichi
Published: March 2006

The relationship between micro‐landform and vegetation structure was studied in a plot that was established on a slope from the ridge to the valley bottom in an evergreen broad‐leaved forest on Amami Ohshima Island, south‐west Japan. Five micro‐landform units recognized in the plot were grouped into the upper and lower slopes by their location in relation to the erosion front, and plant distributions and vegetation structure were compared between them. Although small trees with d.b.h. less than 10 cm occurred almost all over the plot, the occurrence of larger trees was limited mostly to the upper slope. Based on the spatial distribution pattern in the plot, woody species are classified into three groups: group A mostly or strictly confined to the upper slope; group B confined to the lower slope; and group C associated statistically with neither slope. A well‐developed forest stand, whose dominant species were Castanopsis sieboldii ssp. lutchuensis and Schima wallichii, was seen on the upper slope, whereas only a poorly developed stand was seen on the lower slope. The difference in stability of the land surface is likely to be the major cause of the observed differences in stand structure between the upper and lower slopes. It is suggested that the erosion front is important as a line demarcating different habitats within a slope from the ridge to the valley bottom.
Differentiation and maintenance of topo‐community patterns with reference to regeneration dynamics in mixed cool temperate forests in the Chichibu Mountains, central Japan
Authors: Yoshida Naoya , Ohsawa Masahiko
Published: March 2006

Topo‐community structure and dynamics were studied in mixed cool temperate forests, using the regeneration dynamics, to clarify the maintenance mechanisms of community patterns along a microtopographic gradient. The 76 stands studied were classified into two groups (i.e. convex slope and concave slope stands). The soil surface was more eroded on the concave slope than on the convex slope, while water potential was not significantly different between topographies. On the convex slope, even‐aged patches alternated between young phase patches dominated by shade intolerant species, such as Acer rufinerve and Betula grossa, and mature phase patches, with Tsuga sieboldii and Fagus crenata. A slower lateral growth rate of Tsuga canopy trees and the absence of suppressed saplings in the mature phase may prolong the gap phase, which provides a favorable situation to shade‐intolerant species. On the concave slope, patch structure was less clear, and process of replacement of canopy species by previously suppressed individuals of the same species was seen in the mature phase, which was mainly composed of F. crenata, Fagus japonica, Acer sieboldianum and Stewartia pseudo‐camellia. Gaps on the concave slope were formed frequently but were generally closed within 10 years by lateral growth of deciduous canopy trees and by upgrowth of suppressed trees, and thus some individuals underwent recurrent periods of suppression until they reached the canopy. We concluded that soil surface stability and gap encroachment pattern are critical to the maintenance of the community pattern along a microtopographic gradient.
Structure and regeneration of Fraxinus spaethiana‐Pterocarya rhoifolia forests in unstable valleys in the Chichibu Mountains, central Japan
Authors: Ann Seoung Won , Oshima Yasuyuki
Published: March 2006

The structure of temperate deciduous forests dominated by Fraxinus spaethiana and Pterocarya rhoifolia in V‐shaped valleys in the Chichibu Mountains, central Japan was studied to clarify their dynamics, with special reference to disturbance. Forest structure and annual ring analysis revealed that the forests have been subjected to mass movement (mud flow) in the past. The size and age structure, and diameter growth curves, indicated that F. spaethiana is relatively shade tolerant, long living and slow‐growing, while P. rhoifolia is less shade tolerant, short living, but fast growing. Pterocarya rhoifolia appears to depend on large‐scale but rare disturbances. Fraxinus spaethiana establishes its seedlings on relatively unstable substrate in V‐shaped valleys, but once established, they survive a long time with high shade tolerance. The dominance and coexistence of the two species may primarily depend on the intensity and frequency of geomorphological processes.
Vertical variation in fecundity of the intertidal gastropod Monodonta labio caused by different growth rates between tidal zones
Authors: Takada Yoshitake
Published: March 2006

Monodonta labio (Gastropoda: Trochidae) occurs in a wide tidal zone on a boulder‐covered shore in Amakusa, Japan. To investigate sources of variation in reproductive output within a population, the fecundity of M. labio was estimated. Regressions of gonad egg counts on shell width were calculated from samples collected bi‐weekly at three tidal zones: high, mid and low intertidal. Seasonal fluctuations in the regression revealed that individual females spawn at least three times a year. Variation in fecundity between the three tidal zones was not detected at any time in standard 12 mm snails. Due to the high growth rate in the low zone during the reproductive season, annual fecundity in the low zone was larger than that in the high and mid zones. Thus, tidal zone variation in fecundity of M. labio was a result of growth variation between tidal zones.
Nutritional diversity of symbiotic ascidians in a Fijian seagrass meadow
Authors: Koike Isao , Suzuki Takao
Published: March 2006

In a coastal lagoon of Dravuni Island, Fiji, at least six species of compound ascidians, some of them harboring Prochloron as symbiotic algae, were found in a Syringodium‐dominated seagrass meadow. Based on their heterotrophic (filrer feeding rates) and autotrophic (photosynthetic) activities, carbon gain of the ascidians was categorized into two groups: (i) supported by heterotrophic metabolism; and (ii) supported by both heterotrophic and autotrophic metabolisms. Didemnum molle, Lissoclinum bistratum and Lissolinum voeltzkowi belong to the latter group, and the relative contribution of the autotrophic process was a significant portion of their carbon gain (52–74%). These symbiotic ascidians were found in light microhabitats, while the heterotrophic species occupied shady environments rich in suspended organic materials, such as the sheath surface of the seagrass.
Successional change of forest pattern along topographical gradients in warm‐temperate mixed forests in Mt Kiyosumi, central Japan
Authors: Ozaki Kemurio , Ohsawa Masahiko
Published: March 2006

Forest patterns along topographical gradients were compared between second‐ and old‐growth forested watersheds in a warm‐temperate zone of Mt Kiyosumi, central Japan. Three community types were distinguished depending on the topographical habitat type in each watershed, for example, conifer forest was dominated by Abies firma and Tsuga sieboldii on ridge sites, evergreen broad‐leaved forest was dominated by Quercus acuta, Q. salicina and Castanopsis cuspidata var. sieboldii on slope sites, and deciduous forest was dominated by Euptelea polyandra and Cornus controversa in valley sites. Beta diversity and distinctiveness of each topographical community type increased with progression of secondary succession. Conifers and evergreen broad‐leaved trees, which were intermingled with each other on ridges and slopes of the second‐growth watershed, were in turn restricted to the ridge and slope habitat type, respectively, in the old‐growth watershed. The process of this differentiation can be explained by the continuous regeneration of conifers on ridge sites, and its absence on slope sites due to different light conditions caused by progressive canopy closure of evergreen trees on the slope sites toward the old‐growth watershed. In the valley type habitat, frequent soil disturbance, such as landslides and soil creep, hinder the continuous growth of late successional evergreen trees, and thus seral or pioneer deciduous trees can persist in the habitat.
Seedling establishment of Castanopsis cuspidata var. sieboldii and Persea thunbergii on lava and scoria of the 1962 eruption on Miyake‐jima Island, the Izu Islands
Authors: Kamijo Takashi , Okutomi Kiyoshi
Published: March 2006

Seedling establishment of Castanopsis cuspidata var. sieboldii Nakai and Persea thunbergii Kosterm. (Machilus thunbergii Sieb. et Zucc.) in early succession was studied on the lava and the scoria of the 1962 eruption on Miyake‐jima Island of the Izu Islands. While tall individuals (> 1 m) of P. thunbergii were found on both the lava and the scoria, those of C. cuspidata (> 1 m) were found only on the lava. The height growth rate of C. cuspidata was very low on the scoria, and there was no individual of C. cuspidata taller than 0.4 m on the scoria. The proportion of yellow leaved individuals was much higher (37.1%) in C. cuspidata than in P. thunbergii (4.0%) on the scoria, while it was similar between the two species on the lava. Persea thunbergii seemed to be able to establish on both the lava and the scoria, but C. cuspidata established only on the lava. The differences in growth rate and vigor between the two species on the lava and the scoria in early succession may influence later stages of succession.
Zonal plant distribution and edaphic and micrometeorological conditions on a coastal sand dune
Authors: Ishikawa Shin‐Ichi , Furukawa Akio , Oikawa Takehisa
Published: March 2006

Some edaphic and meteorological conditions were examined to detect environmental gradients from shoreline to inland at the Kado‐ori coast, Ibaraki, Japan, in 1989. Zonal distribution patterns of coastal dune plant species, including three ubiquitous perennials, Calystegia soldanella, Carex kobomugi and Ischaemum anthephoroides, were described in relation to the environmental gradients. Environmental gradients were found in water availability, evaporative demand and soil‐water salinity. Water availability, evaluated by thickness of capillary water layer, increased from 10 cm at 20 m to 48 cm at 85 m from the shoreline, reflecting the percentage of fine sand. Evaporative demand, which was evaluated by the evaporation rate from a wet black filter paper, decreased with increasing distance from the shoreline. Soil‐water salinity was lowest (15 mmol/L) at 85 m from the shoreline and highest (90 mmol/L) at 30m. On the coast, C. soldanella, a salt‐tolerant perennial, was distributed mainly in the environmentally harsh area 40–60 m from the shoreline. Ischaemum anthephoroides and C. kobomugi, less salt‐tolerant perennials, occurred mainly 70–80 m from the shoreline, where environmental conditions were more hospitable.
Factors delimiting the boundary between vertically contiguous mussel beds of Septifer virgatus (Wiegmann) and Hormomya mutabilis (Gould)
Authors: Iwasaki Keiji
Published: March 2006

On moderately wave‐exposed rocky shores in middle Japan, the upper interidal mytilid, Septifer virgatus, and lower intertidal mytilid, Hormomya mutabilis, occur together, forming vertically contiguous mussed beds. Factors limiting the lower distribution limit of Septifer and the upper limit of Hormomya were investigated by collections of natural mussel clumps and single‐ and mixed‐species transplantation experiments. Newly settled juvenile Septifer (<5 mm shell length) were significantly fewer in the natural and artificial Hormomya clumps than in the Septifer clumps. Both natural and artificial Hormomya clumps accumulated a much greater amount of sediment than did the Septifer clumps. Hormomya clumps inhibited the recruitment of Septifer, presumably through accumulation of sediment, which resulted in setting the lower limit of the Septifer zone. Survivorship of small (5–10 mm) and large (>15 mm)Hormomya was much lower in Hormomya clumps transplanted upwards into the Septifer zone than it was in Hormomya clumps in the Hormomya zone. In mixed‐species clumps in the Septifer zone, however, survivorship of small Hormomya was not significantly different from that in mixed‐species clumps in the Hormomya zone. Septifer had a positive effect on the survival of small Hormomya and increased the upper limit of Hormomya, presumably by providing shelter and thus protecting them from desiccation. The upper limit of Hormomya zone was thus considered to be set by desiccation exceeding the physiological tolerance of the species.
Survivorship and growth of seedlings of four dipterocarp species in a tropical rainforest of Sarawak, East Malaysia
Authors: Itoh Akira , Yamakura Takuo , Ogino Kazuhiko , Lee Hua Seng
Published: March 2006

Survivorship and growth of seedlings of four dipterocarp species (Dipterocarpus actangulus, D. globosus, Dryobalanops aromatica, Dryobalanops lanceolata) were studied for 2.5 years in a mixed dipterocarp forest in Sarawak, East Malaysia. Predispersal seed predation rates were larger for D. globosus (75%) than D. lanceolata (27–34%) and D. aromatica (18–26%). Less than 20% of the two Dryobalanops seeds were damaged by vertebrates after seed dispersal. During the period from seed dispersal to the time when the seedlings had shed cotyledons, more dispersed seeds died in the two Dipterocarpus (ca 90%) than the two Dryobalanops (ca 60–70%). The major mortality factors during this period were uprooted and seed/seedling predation by insects or vertebrates. After the seedlings shed cotyledons, all species showed constant mortality rates of 34, 15–16, 17 and 6%/year for D. actangulus, D. lanceolata, D. aromatica and D. globosus, respectively, in the forest understorey. Mortality was lower in less shaded conditions than in more shaded ones for D. aromatica and D. actangulus, but not significantly different for D. lanceolata and D. globosus. A majority of dead seedlings were killed by fallen branches or were found standing with wilted leaves, probably due to water stress. No significant correlation was found between seed/seedling mortality and distance from mother trees or the initial density of seeds/seedings for all species. The mean leaf production was positively correlated with the estimated diffuse light factor of their habitats for each species.
White‐tailed deer vary offspring sex‐ratio according to maternal condition and age
Authors: Burke Russell L. , Birch James M.
Published: March 2006

We tested two models of adaptive offspring sex‐ratio that predict opposite optimal reproductive strategies for female white‐tail deer (Odocoileus virginianus). Trivers and Willard's model predicts that does (females) in particularly good condition should produce sons, and Williams refined their model to make specific predictions about optimal offspring number/sex choices. Verme's model results in very different predictions because of very different assumptions about which sex of offspring can best benefit from high levels of maternal resources. We found clear support for the Trivers and Willard/Williams model when we analyzed data from road‐killed does, and we furthermore question several of the assumptions of the Verme model.
Measurement of soil respiration using closed chamber method: An IRGA technique
Authors: Bekku Yukiko , Koizumi Hiroshi , Nakadai Toshie , Iwaki Hideo
Published: March 2006

A closed chamber method (CC‐method) using an infra‐red gas analyzer (IRGA) for measuring soil respiration was examined. Two major factors which potentially cause errors: (i) volume of air sampled from the chamber; and (ii) measuring period of time, were examined in laboratory experiments. Field measurements were also conducted with both the CC‐method and the open‐flow IRGA method (OF‐method) throughout a year. The results of laboratory experiments showed that (i) sampling volume of air should be less than 0.2% of the volume of the chamber; and (ii) the air within the chamber should be sampled several times within 20 min. Field measurements showed that soil respiration rates measured by the CC‐method were not significantly different from those by the OF‐method. The results of this study indicate that the CC‐method is as effective for the measurement of the soil respiration rates as the OF‐method.