bluuebunny/crossref_metadata_2025 huggingface dataset:
Interface optical phonons in spherical multilayer nanostructures
Authors: López I. , Kanyinda‐Malu C. , de la Cruz R. M.
Published: March 2006

Within the dielectric continuum model, we calculate the interface phonons in multilayered spherical nanostructures. The effect of the alloying in the shell material, together with the change in the embedding medium are also analyzed. In all investigated heterostructures, the interface characteristics experiment a constantlike tendency at critical geometrical parameter g c, whose values are sensitively determined by the ratio between dielectric constants of constitutive materials. We observe that the asymptotic limiting interface frequencies slightly depend on the embedding medium. For special cases, the high‐index phonon branches cross each other for specific values of geometrical parameter g . This crossing‐over critically depends on the core‐to‐shell dielectric constants ratio and on the type of host material. Also, we observe that the presence of Ga‐impurity in the shell material makes the highest shell‐like modes independent both on the geometrical parameter g and on the orbital index l . (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth studies, TEM and XRD investigations of iron‐filled carbon nanotubes
Authors: Müller C. , Golberg D. , Leonhardt A. , Hampel S. , Büchner B.
Published: March 2006

The formation mechanism of iron filled carbon nanotubes on oxidized silicon substrates precoated with thin metal layers (Fe, Co) has been studied. These filled structures were aligned perpendicular to the substrate surface. The nanotubes were produced by the thermal decomposition of ferrocene in an argon flow. We have studied the nanotube morphology and geometry (diameter, length) in detail. Transmission electron microscopy (TEM), X‐ray diffraction (XRD) and selected area electron diffraction (SAED) were used to analyze the iron nanorods inside the nanotubes. These investigations have revealed a majority fraction of α‐Fe and small amounts of γ‐Fe and Fe3C. Moreover only single crystalline iron was found. In summary we conclude that iron filled carbon nanotubes with this CVD route are formed via an open‐ended, base growth mechanism. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of MK‐0431 in human plasma using high turbulence liquid chromatography online extraction and tandem mass spectrometry
Authors: Zeng Wei , Musson Donald G. , Fisher Alison L. , Wang Amy Qiu
Published: March 2006

A robust and sensitive method using high turbulence liquid chromatography (HTLC) online extraction with tandem mass spectrometry (MS/MS) for the determination of MK‐0431 in human plasma was developed and validated to support the clinical studies. This HTLC online extraction method eliminated the time‐consuming offline sample extraction procedures and significantly increased productivity. A narrow bore large particle size reversed‐phase column (Cyclone, 50 × 1.0 mm, 60 µm) and a BDS Hypersil C18 column (30 × 2.1 mm, 3 µm) were used as extraction and analytical columns, respectively. The linear dynamic range of the calibration curve was 0.5 to 1000 ng/mL. Intraday validation was conducted using five calibration curves prepared in five lots of human control plasma, and the intraday precision (RSD%) was from 2.4 to 9.0% and the accuracy was from 98.0 to 103% of the nominal value. The intraday precision (RSD%, n = 5) for plasma quality control (QC) samples varied from 2.0 to 5.3% and accuracy from 103 to 105% of the nominal value. The interday precision (RSD%) for 100 sets of plasma QC samples in 29 analytical runs varied from 6.3 to 9.0% and the accuracy from 98.8 to 104% of the nominal value. No significant difference was observed between the interday and intraday precision and accuracy of the QC samples. Copyright © 2006 John Wiley & Sons, Ltd.
Bilirubin degradation by uncoupled cytochrome P450. Comparison with a chemical oxidation system and characterization of the products by high‐performance liquid chromatography/electrospray ionization mass spectrometry
Authors: De Matteis Francesco , Lord Gwyn A. , Kee Lim Chang , Pons Nicoletta
Published: March 2006

Bilirubin is a protective antioxidant; however, when its conjugation and excretion are impaired, as in neonatal and hereditary jaundice, bilirubin accumulates and may cause severe neurotoxicity. Degradation of bilirubin takes place (a) on interaction with oxidative free radicals and (b) when cytochrome P450 (CYP) enzymes are uncoupled by polyhalogenated substrate analogues. The products of pathways (a) and (b) above have now been characterized by high‐performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI‐MS) and the mechanisms of fragmentation in part clarified. Oxidation of bilirubin by uncoupled CYP1A5 and by a Fe‐EDTA/H2O2 system produced both biliverdin and an identical profile of dipyrrolic fragments, as detected by positive ESI‐MS. A similar profile of oxidation products was found from mesobilirubin, all showing the expected increase in mass, thus providing direct evidence for fragmentation at the central methene bridge of the tetrapyrroles. Two degradation products, also detected by negative ESI‐MS, were characterized as dipyrroles retaining the central bridge carbon, with one or two oxygen atom(s) bound (probably as the aldehyde and hydroperoxide derivatives). Ions compatible with propentdyopents and bilifuscins were also detected, but here the assignment was less certain. It is concluded that the first step in the oxidation of bilirubin may be hydrogen abstraction at the central methene bridge. This is followed either by loss of another hydrogen to give biliverdin, or by oxygen binding and fragmentation. Fe‐EDTA/H2O2 and uncoupled CYP(FeO) may both initiate the reaction, the latter in an attempt to reduce the ferryl oxygen to water. These studies shed light on the CYP uncoupling mechanism and are of potential significance for the therapy of severe jaundice. Copyright © 2006 John Wiley & Sons, Ltd.
Matrix‐suppressed laser desorption/ionisation mass spectrometry and its suitability for metabolome analyses
Authors: Vaidyanathan Seetharaman , Gaskell Simon , Goodacre Royston
Published: March 2006

Matrix‐assisted laser desorption/ionisation (MALDI) mass spectrometry was investigated for the simultaneous detection of several metabolites, as applicable to global metabolite analysis (metabolomics). The commonly employed organic matrices α‐cyano‐4‐hydroxycinnamic acid and 3,5‐dihydroxybenzoic acid, in both the crystalline and ionic liquid forms, were investigated. The employment of a low matrix‐to‐analyte molar ratio suppressed matrix peaks and was effective in detecting all the metabolites with a unique mass in a 30‐metabolite synthetic cocktail, albeit to varying degrees. These matrix‐suppressed laser desorption/ionisation (MSLDI) analyses were performed in the positive ion mode, and metabolites were detected as the protonated [M+H]+, sodiated [M+Na]+ or potassiated [M+K]+ species. The spectral signals were dominated by basic metabolites. It was possible to detect components of a synthetic cocktail when it was spiked quantitatively into a microbial extract, demonstrating the feasibility of using the technique for detecting metabolite signals in a complex biological matrix. However, analyte suppression effects were noted when the relative proportion of one analyte was allowed to increasingly dominate the others in a mixture. The implications of the findings with respect to applications in metabolomic investigations are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
A comparison of denominator degrees of freedom methods for multiple observer ROC analysis
Authors: Hillis Stephen L.
Published: March 2006

There are several methods available for analysing multireader ROC studies that generalize results to both the reader and case populations. Two of these methods—the Dorfman–Berbaum–Metz (DBM) method and the Obuchowki–Rockette (OR) method—appear to be quite different in their original formulations. However, recently it has been shown that the DBM and OR procedures yield the same test statistic when based on the same accuracy measure and covariance estimation method, but inferences can vary depending on which denominator degrees of freedom (ddf) method, DBM or OR, is used. I show in simulations that there are problems with both ddf methods: OR is ultraconservative with significance levels considerably below the nominal level, and DBM can result in extremely wide confidence intervals because the ddf can be close to zero. I propose a new ddf method that overcomes both of these problems and can be used with either the OR or DBM procedure. Copyright © 2006 John Wiley & Sons, Ltd.
Analysis of interval‐censored data from circular migrant and non‐migrant sexual partnerships using the EM algorithm
Authors: Zuma K. , Lurie M. , Jorgensen M.
Published: March 2006

In epidemiological studies where subjects are seen periodically on follow‐up visits, interval‐censored data occur naturally. The exact time the change of state (such as HIV seroconversion) occurs is not known exactly, only that it occurred sometime within a specific time interval. Methods of estimation for interval‐censored data are readily available when data are independent. However, methods for correlated interval‐censored data are not well developed. This paper considers an approach for estimating the parameters when data are interval‐censored and correlated within sexual partnerships. We consider the exact event times for interval‐censored observations as unobserved data, only known to be between two time points. Dependency induced by sexual partnerships is modelled as frailties assuming a gamma distribution for frailties and an exponential distribution on the time to infection. This formulation facilitates application of the expectation‐maximization (EM) algorithm. Maximization process maximizes the standard survival frailty model. Results show high degree of heterogeneity between sexual partnerships. Intervention strategies aimed at combating the spread of HIV and other sexually transmitted infections (STI)s should treat sexual partnerships as social units and fully incorporate the effects of migration in their strategies. Copyright © 2006 John Wiley & Sons, Ltd.
Monitoring the introduction of a surgical intervention with long‐term consequences
Authors: Gorst‐Rasmussen A. , Spiegelhalter D. J. , Bull C.
Published: March 2006

Surgical innovations are often introduced for their expected long‐term benefits, but the decision to abandon the existing treatment must be based on the available short‐term data and rational judgment. We present a framework for monitoring the introduction of a surgical intervention with long‐term consequences and failure‐time endpoints. The framework is based on Bayesian methods, and formally combines study data, clinical opinion, and external evidence to construct a posterior survival function from which intuitive summary statistics can be extracted to aid decision making. It incorporates learning effects and is adaptable to a wide variety of settings. The methods are illustrated on survival data from a cohort of 325 consecutive neonates treated for simple transposition of the great arteries with either the Senning or the Switch operation during the period 1978–1998. Copyright © 2006 John Wiley & Sons, Ltd.
Log‐linear non‐uniform association models for agreement between two ratings on an ordinal scale
Authors: Valet Fabien , Guinot Christiane , Mary Jean Yves
Published: March 2006

In agreement studies, when objects are rated independently by two raters (or twice by the same rater), an association between their ratings on two categories arises, reflecting the distinguishability of these two categories for these raters. When ratings are performed on an ordinal scale, this association between ratings on two categories increases when the distance between these categories increases on the ordinal scale. Goodman's log‐linear models derived for the analysis of agreement between two raters on an ordinal scale assume that distinguishabilities between adjacent categories are either constant, ora priorifixed. Log‐non‐linear models that allow variations of the distinguishabilities between adjacent categories along the scale, may lead to difficulties in parameter estimation.

This paper describes a new class of log‐linear non‐uniform association models. These models extend the log‐linear uniform association model by allowing variations of distinguishability between adjacent categories (along the scale). These new models are used to analyse ordinal agreement between dermatologists when assessing the severity of different cutaneous signs of ageing on women faces. Copyright © 2006 John Wiley & Sons, Ltd.
Acoustic diffraction by a pair of poroelastic cylinders
Authors: Hasheminejad S.M. , Avazmohammadi R.
Published: March 2006

This study treats the interaction of a plane compressional sound wave with a cluster of two fluid‐saturated porous elastic cylinders submerged in an unbounded acoustic medium. The novel features of Biot dynamic model for description of poroelastic material behaviour along with the appropriate wave field expansions, the pertinent boundary conditions, and the translational addition theorem for cylindrical wave functions are employed to develop a closed‐form solution in the form of infinite series. The theoretical model was extended to consider the case of sound diffraction by a pair of absorbing cylinders with locally reacting or extended reaction boundaries. The analytical results are illustrated with numerical examples in which two identical air‐saturated glass wool cylinders are insonified by a plane sound wave at end‐on/broadside incidence. The most fundamental acoustic field quantity, namely, the scattering form function amplitude is evaluated and discussed for representative values of the parameters characterizing the system. The effects of incident wave frequency, angle of incidence, and proximity of the two cylinders are examined. Particular attention has been focused on multiple scattering interactions as well as the surface reaction modelling effects. Numerical comparison is made with the case of acoustic diffraction by a pair of absorbing cylinders with locally reacting or extended reaction boundaries. Limiting cases involving two rigid cylinders and also a pair of penetrable (fluid) cylinders are considered and good agreements with well‐known solutions are established.
Variation in nature: its implications for zoo elephant management
Authors: Hutchins Michael
Published: March 2006

Despite many advances in animal care and welfare over the past few decades, zoos have been criticized recently for the quality of their elephant management programs. More specifically, critics have argued that elephants live miserable lives in captivity and thus should not be kept in zoos. Poor health and reproductive success, they say, are the result of the combined impact of: a lack of exercise; exposure to cold temperatures and disease; and stress due to the use of “brutal” training techniques, chaining and inappropriate social environments. Everyone, including zoo professionals, seems to agree that improvements in zoo elephant management are necessary and appropriate. However, there is considerable disagreement on how to proceed and little information on which to base such decisions. One tactic that the critics have adopted in their efforts to promote change is their frequent reference to “nature” as a yardstick for gauging the adequacy of zoo animal management and care. An argument is made that direct zoo–wild comparisons are of questionable utility and may be invalid from a scientific perspective. Some critics talk about “nature” as if it represented a fixed set of rules by which captive managers must either abide by or risk diminishing the health and welfare of their charges. However, many aspects of elephant natural history vary greatly depending on prevailing environmental conditions and elephants may be much more flexible than many critics are giving them credit for. Thus, although zoo animal managers should look to nature for clues about how to best care for captive elephants, they should not feel constrained by them. This revelation is not intended as an excuse for poor elephant management or to support the status quo. On the contrary, a better approach is to develop realistic and biologically meaningful metrics that reflect the quality of elephant care and welfare and to use them to measure the success of evolving zoo elephant programs. Zoo Biol 25:161–171, 2006. © 2006 Wiley‐Liss, Inc.
Histidinaemia. Part II: Impact; a retrospective study
Authors: Rosenmann A. , Scriver C. R. , Clow C. L. , Levy H. L.
Published: March 2006

Forty‐two articles published between 1961 and 1977 describing 43 probands and 26 siblings with histidinaemia were used for the retrospective study. Our objective was to describe the apparent impact of the mutation on development and health in human histidinaemia. The findings were similar to those of an earlier survey (Popkinet al., 1974). Most probands (79 %) had a disadaptive CNS phenotype (mental retardation, impaired speech, seizures, aberrant behaviour, and/or learning disorder); half the histidinaemic siblings had a similar phenotype. The modal IQ score was 70; age at recognition of symptoms (CNS phenotype) varied from 1 month to 16 y (modal age 2½ y). There was no correlation between blood histidine (reported values) and occurrence of severity of CNS phenotype. Thirty per cent of histidinaemia subjects, for whom the perinatal history was described, had an abnormal experience. Reported cases with the CNS phenotype apparently represent a very small fraction (about 1 %) of all subjects with histidinaemia; this implies that the histidinaemia phenotype is not disadaptive in man.
Histidinaemia. Part III: Impact; a prospective study
Authors: Coulombe J. T. , Kammerer B. L. , Levy H. L. , Hirsch B. Z. , Scriver C. R.
Published: March 2006

We describe a prospective study of histidinaemia. Probands and siblings (n = 21) with typical histidinaemia in 16 families were ascertained by newborn screening; diagnosis was confirmed by appropriate investigations in each subject; none had been treated by low histidine diet. The median age of subjects with histidinaemia was 9.5 y (mean 10.0, SD 3.5, range 6‐18). Age‐matched sib‐pairs and their mothers were studied. IQ scores (Full Scale, Verbal and Performance Scores), Visual‐Motor Integration Performance (Bender Gestalt and Koppitz scores), Wide Range Achievement Test (Reading and Mathematics), school performance, and psychological history were evaluated, as well as the medical history (pregnancy, delivery, neonatal, post‐natal development). Findings were correlated with biochemical phenotype. CNS development in histidinaemic subjects (mean and distribution of scores) was normal; outlier values did not correlate with degree of histidinaemia. We can conclude that histidinaemia detected by newborn screening is a non‐disadaptive phenotype.
A clinical trial of fibroblast transplantation for the treatment of mucopolysaccharidoses
Authors: Gibbs D. A. , Spellacy E. , Tompkins R. , Watts R. W. E. , Mowbray J. F.
Published: March 2006

This paper reports the clinical and biochemical results in six patients with Hurler disease (Mucopolysaccharidosis IH; McKusick 25280), two patients with Hunter disease (Mucopolysaccharidosis II; McKusick 25285) and one patient with Sanfilippo B disease (Mucopolysaccharidosis IIIB; McKusick 25292) who were treated by fibroblast transplantation. Except for one patient who died for a coincidental reason, the patients have been studied for between 2.5 and 4.5 years. The clinical course of the disease was not materially altered. There was no evidence that the patients had developed immune responses against the transplanted fibroblasts. Transplantation did not produce measurable levels of either α‐l‐iduronidase (EC 3.2.1.76) in the leukocytes from patients with Hurler disease or ofN‐acetyl‐α‐d‐glucosaminidase (EC 3.2.1.50) in the plasma of the patient with Sanfilippo B disease. Under the conditions used for the assay, leukocytes from the patients with Hunter disease had detectable levels of residual α‐l‐idurono‐2‐sulphate sulphatase activity which were increased after the transplants, although these changes were of inconstant size and their time course was not consistently related to the transplantations. Cytogenetic studies in cases where the donor was of the opposite sex detected only cells of the recipient's sex among the fibroblasts grown from biopsies of the transplantation sites. The technique used would have detected a donor to recipient cell ratio of 1:100. We found no consistent long‐term trends in the excretion patterns of glycosaminoglycans and oligosaccharides from either a quantitative or qualitative point of view which could be specifically related to the transplantation. The combined administration of immunosuppressive doses of prednisolone and azathioprine was associated with an increased excretion of the lower molecular weight glycosaminoglycans. We conclude that fibroblast transplantation is not therapeutically useful in the diseases studied.
Pollination systems in a warm temperate evergreen broad‐leaved forest on Yaku Island
Authors: Yumoto Takakazu
Published: March 2006

Animal pollination in a warm temperate evergreen broad‐leaved forest was observed on Yaku‐shima Island, south of Kyushu, Japan. Three groups of plants were categorized: canopy‐flowering tree species, understory‐flowering tree species, and climber and epiphyte species. Each of these formed different pollination systems. The canopy‐flowering tree species had shallow, dish‐shaped flowers and utilized various types of opportunistic pollinators. Most of the climber and epiphyte species had deep, tube‐shaped flowers and specialized pollinators, although some climber species which bloomed in the canopy especially in winter, had opportunistic pollinators. The understory‐flowering tree species had large dish‐ or funnel‐shaped flowers and endothermic pollinators able to tolerate the dark and cold conditions under the canopy. The individual trees of canopy‐flowering tree species produced large numbers of flowers simultaneously (mass‐flowering) and had a well synchronized flowering period. Each canopy‐flowering tree species segregated its flowering time from those of the anothers. Climber and epiphyte species and most of the understory‐flowering tree species produced small numbers of flowers sequentially (extended flowering) and showed a long flowering period.
Seed dispersal of the Korean pine,Pinus koraiensis, by the red squirrel,Sciurus vulgaris
Authors: Miyaki Masami
Published: March 2006

Seed hoarding behavior of the red squirrel,Sciurus vulgaris, was studied in relation to the amount of dispersed seeds of the Korean pine,Pinus koraiensis, and the distribution of its seedlings. After removing a cone from a tree, squirrels sat on the ground and ripped off its cone scales before transporting it. A mean of 3.2 seeds were scatter‐hoarded per hole. Of 7.7×104mature seeds produced in a 0.21 ha planted Korean pine forest, 22% were estimated to be directly eaten by four squirrels, 9% were hoarded by them in the pine forest and 65% were cached outside the forest. Squirrels rediscovered hoarded seeds frequently, until the ground was covered with snow, during the period from snow fall until seed germination the next spring, few hoarded seeds were utilized. Korean pine seedlings were found up to 600 m from their mother trees. Scatter‐hoarding by squirrels extensively contributes to seed dispersal to places suitable for the regeneration of the Korean pine. The large size of the cone, the absciss‐layer at the cone penduncle, the infrequent dehiscence of cone scales, the large and wingless seeds, and the thick seed‐coats have probably all been specialized to facilitate utilization by GenusSciurus.
Reproductive ecology of three ocypodid crabs I. The influence of activity differences on reproductive traits
Authors: Henmi Yasuhisa , Kaneto Mitsuaki
Published: March 2006

Reproductive traits of three ocypodid crabs, Scopimera globosa, Ilyoplax pusillus and Macrophthalmus japonicus, were compared. S. globosa and I. pusillus, inhabiting the upper‐middle intertidal zone, produced 1–2 large broods per year, whereas M. japonicus, inhabiting the lower intertidal zone, produced 4–5 small broods per year. In S. globosa and I. pusillus, ovigerous females remained in their plugged burrows without feeding until their eggs hatched. On the other hand, female M. japonicus fed actively on surface mud while incubating. We concluded that few large broods may be advantageous in crab species that incubate in burrows, whereas continuous small broods may be advantageous in species that feed actively while incubating.
Production ecology of phyto‐ and zooplankton in a eutrophic pond dominated byChaoborus flavicans(Diptera: Chaobolidae)
Authors: Iwakuma Toshio , Shibata Kin'ya , Hanazato Takayuki
Published: March 2006

Primary production of phytoplankton and secondary production of a daphnid and a chaoborid were studied in a small eutrophic pond. The gross primary production of phytoplankton was 290 gC m−2per 9 months during April–December. Regression analysis showed that the gross primary production was related to the incident solar radiation and the chlorophyllaconcentration and not to either total phosphorus or total inorganic nitrogen concentration. The mean chlorophyllaconcentration (14.2 mg m−3), however, was about half the expected value upon phosphorus loading of this pond. The mean zooplankton biomass was 1.60 g dry weight m−2, of whichDaphnia roseaand cyclopoid copepods amounted to 0.69 g dry weight m−2and 0.61 g dry weight m−2, respectively. The production ofD. roseawas high during May–July and October and the level for the whole 9 months was 22.6 g dry weight m−2.Chaoborus flavicansproduced 10 complete and one incomplete cohorts per year. Two consecutive cohorts overlapped during the growing season. The maximum density, the mean biomass, and the production were 19,100 m−2, 0.81 g dry weight m−2, and 11.7 g dry weight m−2yr−1, respectively. As no fish was present in this pond, the emerging biomass amounted to 69% of larval production. The production ofC. flavicanslarvae was high in comparison with zooplankton production during August–September, when the larvae possibly fed not only on zooplankton but also algae.
Climate and vegetation in China II. Distribution of main vegetation types and thermal climate
Authors: Fang Jing‐yun , Yoda Kyoji
Published: March 2006

The authors examined relationships between Kira's warmth index (WI) and four other important thermal indices: the sums of daily mean temperatures above 5°C and 10°C, Thornthwaite's potential evapotranspiration (PE) and Holdridge's annual biotemperature. The thermal records of 671 meteorological stations evenly located all over China were used to make these comparisons. Close correlations were found within the four relationships, and accordingly WI was used to analyse the thermal distributions of the main vegetation types. Vegetation types around the 671 stations were read from a vegetation map with a scale of 1/4000000. Vegetation types at 269 stations corresponded to the natural or seminatural vegetation, and 29 vegetation types were distinguished by arranging the 269 data into the same or similar types. The geographical distribution of these 29 types and the corresponding main climatic features were described. The relations between WI and distribution of these vegetation types were discussed in detail. As a result, WI values (°C month) corresponding to the vegetation zones could be summarized as follows: (1) arctic or alpine vegetation zone: 0–15; (2) boreal or subalpine vegetation zone: 15‐(50–55); (3) cool‐temperate vegetation zone: (50–55)–(80–90); (4) warm‐temperate vegetation zone: (80–90)–(170–180). These values almost coincided with Kira's values.
A preliminary study of changes in forest stratification along environmental gradients in Southeast Asia
Authors: Yamakura Takuo , Sahunalu Pongsak , Karyono
Published: March 2006

Changes in forest stratification along environmental gradients in Southeast Asian forests were studied, by applying Quantification Method I to the records of tree height inventories and environmental conditions in 29 study forest stands. To stratify individual trees into subpopulations in a stand, an empirical and graphical method was used. After stratifying all the component individuals of the stand into subpopulations, the number of subpopulations per stand and mean tree height per subpopulation were calculated and adopted as indices of forest stratification. Of the two indices, the latter index changed linearly with respect to the maximum tree height in the stand. Hence, the number of subpopulations and the maximum tree height as a substitute for mean tree height per subpopulation were biotic dependent variables in the application of Quantification Method I, while abiotic independent variables were the following six categorized environmental factors: the number of wet months with over 100 mm month−1 rainfall in a year, occurrence of fog, mean annual temperature, magnesium accumulation in mineral soil, soil water drainage, and forest fire. It was concluded that these biotic and abiotic variables were the components of multivariate regression models, which successfully explained the development of forest stratification in terms of habitat conditions.
Changes in the chemical composition of carbohydrates and proteins in surface water during a bloom of Microcystis in Lake Suwa
Authors: Amemiya Yumiko , Kato Kenji , Okino Tokio , Nakayama Oki
Published: March 2006

Carbohydrates and proteins in surface water during a bloom of Mictrocystis, which is the dominant summer phytoplankton in Lake Suwa, were analyzed in order to evaluate the function of Microcystis in organic matter metabolism. Glucose was the predominant sugar constituent of the cellular carbohydrate fraction and decreased in quantity from inside towards the outside of the cell through the slime layer. Other constituent sugars, on the other hand, were present in larger proportions in the lake water. Although the sugar composition of the cells did not change in July and August, during the first period of the Microcystis bloom, it changed appreciably in September when the water temperature decreased below 20°C accompanied by the decrease in solar radiation and a marked change in nutrient concentration.

It appears that the sugar composition of the cells may change in response to some environmental stresses. In addition, a temporal change in the sugar composition was found, particularly in the fraction containing the slime extracted by shaking. Among the constituent amino acids of the cells, the percentage of arginine, aspartic acid and leucine decreased from inside toward the outside of the cell, while glutamic acid, threonine, serine and glycine showed an opposite trend. In contrast to the carbohydrates, the percentage composition of each amino acid varied little throughout the period of the bloom.
Germination traits and seed‐bank dynamics of a biennial plant, Oenothera glazioviana Micheli
Authors: Kachi Naoki
Published: March 2006

A study was conducted on the germination traits and seed‐bank dynamics of Oenothera glazioviana (=O. erythrosepala), which sets seed in August in sand‐dune systems in Japan. More than 90% of freshly matured seeds germinated over a wide range of temperature in light, but less than 10% did so in continuous darkness. Stratification (chilling under moist conditions) was ineffective in diminishing the light‐requirement for germination. When fresh seeds were imbibed for 24 h including a 12‐h light period, followed by 7‐day air‐drying, 94% of them became germinable in the dark at 25°C, but remained dormant at less than 15°C. of seeds collected in March from capsules of dead plants, 58% germinated in the dark at 25°C. After four cycles of alternatc 1‐day wetting followed by 2‐day drying or 1.5‐day wetting followed by 1.5‐day drying under a 12‐h photoperiod, the fraction of viable seeds declined from 76% to 40% and 22%, respectively, due to germination during the wet periods.

Seed‐bag experiments were conducted in the field, using seeds given and not given a light‐stimulus. Forty percent of the light‐stimulated seeds germinated in the soil, whereas the seeds without a light‐stimulus remained dormant throughout the experiment. When seeds were placed on the soil surface or at a depth of 0.5‐1 cm, the proportion of germinable seeds declined during late spring and autumn, but not during winter and early spring. The seed‐bank size of a natural population just prior to current seed dispersal was 2–3% of the seed production in the previous year, suggesting a high turnover rate of the seed‐bank.
Field measurement of net photosynthesis of mosses at Langhovde, East Antarctica
Authors: Ino Yoshio
Published: March 2006

Net photosynthesis and dark respiration (CO2 flux) of Antarctic mosses were measured at Langhovde, East Antarctica, from 9 to 17 January 1988. Moss blocks were taken from communities in the Yukidori Valley (69°14′30″S, 39°46′00″E) at Langhovde. Each block was composed of Ceratodon purpureus and Bryum pseudotriquetrum, or B. pseudotriquetrum. The upper part of the block was used to measure net photosynthesis and dark respiration. The net photosynthesis of each sample was measured in the field for one or three days with two infrared CO2 gas analyzers and an assimilation chamber. The relationships of net photosynthetic rate and dark respiration rate, to the water content of the sample, the intensity of solar radiation and the moss temperature were estimated from the field data. The maximum rate of net photosynthesis was about 4 μmol CO2 m−2s−1 at saturating radiation intensity and at optimum temperature, about 10°C. Environmental features of moss habitats in the Yukidori Valley are discussed in relation to these results.
Holocene sedimentary history of some coastal plains in Hokkaido, Japan V. Sedimentary history of Kushu Lake and Akkeshi
Authors: Kumano Shigeru , Ihira Masashi , Kuromi Mitsuhiro , Maeda Yasuo , Matsumoto Eiji , Nakamura Toshio , Matsushima Yoshiaki , Sato Hiroshi , Matsuda Isao
Published: March 2006

Diatom assemblages of sediments obtained from Kushu Lake and Akkeshi were analyzed in order to clarify the local Holocene sedimentary history. The results revealed the following: 1) Sometime before about 9000 yr B.P., Kushu Lake was originally a freshwater environment. 2) The first marine diatom zone (MD1Zone) was deposited on the bottom of the paleo‐Kushu Bay between 8500 and 6000 yr B.P. 3) This site changed to become the bottom of the paleo‐Kushu Lagoon around 6000 yr B.P. owing to the formation of a bay‐mouth bar across the paleo‐Kushu Bay and the first Holocene regression resulted in a freshwater lake at about 4500 yr B.P. 4) At this time, the Akkeshi site changed from a sublittoral shore in a drowned valley to a peat moor. 5) The second Holocene transgression at about 3000 yr B.P. was detected at the Akkeshi site. 6) At Kushu Lake site the occurrence ofMastogloia ellipticabetween 7000 and 5000 yr B.P. suggested the influx of the Tsushima warm current into the Japan Sea.
Climate and vegetation in China IV. Distribution of tree species along the thermal gradient
Authors: Fang Jing‐yun , Yoda Kyoji
Published: March 2006

The aim of this study was to examine correlations between vegetational zones and thermal climate on the basis of analysis of the thermal distribution of main‐component trees in each zone. The whole and main thermal distribution ranges for 73 tree species were obtained from their distributions along the warmth index (WI) gradicnt. Cluster analysis using the WI values at the upper and lower limits of the main distribution ranges as parameters gave seven species groups. The geographical distributions of the species in each group were described. Moreover, the frequency distribution curves of the seven species groups were determined along the WI grandient, and four borderlines (lines I, II, III and IV) were found among them. The WI values at the lines I, II and IV were 50, 90, 175°C month, respectively, and corresponded to boundaries between the subarctic and cool‐temperate zones (I), the cool‐and warm‐temperate zones (II) and the warmtemperated and subtropical/tropical zones (IV), respectively. Line III corresponded to a WI of 135°C month. The WI values at the forest limit and at the lower limit of the subarctic forest were estimated, and their averages were 15.2 and 49.6°C month, respectively. In conclusion, thermal climatic zones in China could be divided by the following WI values: alpine (arctic) zone, WI<15; subarctic zone, 15–50; cool‐temperate zone, 50–90; warm‐temperate zone, 90–175; subtropical/tropical zone >175°C month.
Throughfall, stemflow and interception of rainwater in an evergreen broadleaved forest
Authors: Masukata Hiromi , Ando Makio , Ogawa Husato
Published: March 2006

In order to analyze the dyanmics of heavy metals in a forest ecosystem, throughfall and stemflow were collected for individual rain showers in an evergreen broad‐leaved forest dominated by Castanopsis cuspidata. The relation between throughfall (or stemflow) (Px) and gross rainfall (P) was approximated by a linear regression equation Px=a(P‐b). The values of coefficient “a” were 0.32–2.02 for throughfall at each sampling point and the mean values for 1976 and 1977–1978 were 0.682 and 0.767, respectively. The stemflow volume differed widely among individual trees, depending mainly on the tree form of each species. In particular, the tree form of Pasania edulis was found to be especially suited to collecting stemflow. One P. edulis tree collected 64% of the rainwater that fell onto its crown as stemflow. The ratio of stemflow to gross rainfall decreased in summer resulting from an increase in leaf biomass and an increase in air temperature. In fact, the values of coefficient “a” for mean stemflow per unit area were 0.180 for summer and 0.229 for other seasons in 1976, and 0.145 for summer and 0.155 for other seasons in 1977–1978 for different sampled trees.
The role of seed dispersal and seedling traits in colonization and coexistence of Salix species in a seasonally flooded habitat
Authors: Niiyama Kaoru
Published: March 2006

Regeneration traits of six co‐occurring Salix species were studied on a floodplain of the Sorachi River, central Hokkaido, Japan, and their colonization success and coexistence in a local habitat were discussed. Mixed Salix communities contained six Salix species; dominant:S. sachalinensis; four subordinates:S. rorida, S. pet‐susu, S. miyabeana and S. subfragilis; rare species:S. jessoensis. Their phenology, falling velocity and longevity of seeds, and the effects of microtopography and soil texture on seedling establishment were studied. The six Salix species had overlapped seed dispersal periods that coincided with the decrease of water level after a predictable spring flood. This coincidence was crucial for the colonization success because the seedlings were established on wet soils left by the decreasing water level. They showed two types of regeneration trait, specialization and generalization. S. rorida and S. subfragilis showed contrasting regeneration traits; early vs. late seed dispersal, large vs. small seeds, seedling distribution on coarse vs. fine soils, respectively. These two species rarely co‐occurred. On the other hand, the dominant S. sachalinensis had an intermediate seed size and dispersal timing, and a wide range of seedling distribution from coarse to fine soils. These results revealed that flooding seasonality influenced the colonization success together with the regeneration traits of Salix species, and that coexistence of the Salix species was facilitated primarily by regeneration niche separation related to flooding seasonality and soil heterogeneity.
Decreased reproductive rate of the spider, Nephila clavata, inhabiting small woodlands in urban areas
Authors: Miyashita Tadashi
Published: March 2006

The reproductive characteristics and feeding conditions of the spider, Nephila clavata, were examined at some urban and non‐urban woodland sites. More than 80% of females were gravid by late October in both non‐urban and large urban woodlands, whereas only 10%–30% were gravid in small urban woodlands. The expected number of eggs per female in mid‐October was also lower in the small urban woodlands, although body length was not reduced. This suggests that reproductive failure was not caused by food shortage during the nymphal stage. Relative food consumption rate, prey size, biomass and size of potential prey during the adult stage all tended to be lower in small urban woodlands. These results suggest that decreased reproduction of N. clavata in small urban woodlands is caused by food shortage during the adult stage, particularly a shortage of large insects.
Effects of deer browsing on the early stage of pyrogenic succession on Miyajima Island, southwestern Japan
Authors: Okuda Toshinori , Nakane Kaneyuki
Published: March 2006

The early stage of forest regeneration on Miyajima Island, southewstern Japan, was studied for three years after a fire in 1984, with respect to the effects of deer browsing. The regeneration patterns of woody species, in terms of the biomass increment and browsing damage to plants, were classified into the following three groups: non‐ or rarely browsed species with little increment of biomass, heavily browsed with little increment, and heavily browsed with large increment. The aboveground biomass increased from 0.4 kg to 2.7 kg per 100 m2 during three years, and was less than half of the biomass obtained in other burnt pine forests on the adjacent deer‐free islands. About 28% of the plant biomass was consumed by deer. The effects of browsing on forest regeneration were heavier at lower than that at the higher altitudes. On this island, deer browsing seems to have an important effect on vegetational succession in the burnt areas.
Growth analysis of Quercus serrata seedlings within Miscanthus sinensis grass canopies differing in light availability
Authors: Tang Yanhong , Washitani Izumi , Tsuchiya Takayoshi , Iwaki Hideo
Published: March 2006

The effects of different light regimes on the survival, growth and morphology of Quercus serrata seedlings were studied in canopies of Miscanthus sinensis. The seedlings of various ages (0–3 yr) were grown in three light regimes: under a dense M. sinensis canopy (TG plot) receiving 2.5%–8.7% of full sunlight, under a relatively sparse canopy (SG plot) receiving 3.8%–16.1% of light and in an adjacent open site (NG plot). There was a little difference in the survival of Q. serrata seedlings among the three plots. Height and diameter of stem and total leaf area of the seedlings were significantly lower in the shadier plots. However, the first (bottom) flush of the stem was significantly longer in the TG plot than in the NG and SG plots. Total dry weights of individual 1‐ and 2‐yr‐old Q. serrata seedlings in the TG plot were reduced to about one‐twelfth of those in the NG plot. Although the relative proportion in dry weight of each organ did not differ significantly among the plots, leaf area ratio, specific leaf area and stem height per unit dry weight were significantly higher in shadier plots. The leaf area per unit stem height was increased considerably in the sunnier plots.
Photosynthetic characteristics and water use efficiency of three coastal dune plants
Authors: Ishikawa Shin‐ichi , Oikawa Takehisa , Furukawa Akio
Published: March 2006

To clarify the ecophysiological characteristics of plants growing on a coastal dune, net photosynthetic rate (Pn) and leaf conductance (g1) of three perennial species in Japanese coastal regions, Ischaemum anthephoroides (C4), Carex kobomugi (C3) and Calystegia soldanella (C3), were compared under controlled environmental conditions and field conditions at the kado‐ori coast at Ohno Village, Ibaraki. I. anthephoroides achieved photosynthetic CO2 saturation at ca. 100 μll−1 intercellular CO2 concentration (C1), and its Pn was not light‐saturated at a high photosynthetically active photon flux density (PPFD) of 1000 μmol m−2s−1. This C4 species showed a high optimal leaf temperature for Pn (35°C) and a low g1 (0.1 mol H2O m−2s−1), permitting maintenance of the highest water use efficiency (WUE, the ratio of Pn to transpiration rate (Tr)) in the field among the three species. At light saturation, C. soldanella had the lowest Pn and g1 and a similar carboxylation efficiency related to C1 (Pn/C1 ratio) as Carex kobomugi. Calystegia soldanella also had a high optimal temperature for Pn (30°C), and achieved higher WUE than Carex kobomugi, as a result of efficient stomatal regulation. In contrast, at the optimum temperature C. kobomugi had a high Pn comparable to I. anthephoroides due to a high g1 of 0.3 mol H2O m−2s−1, but with high temperature treatments Pn and g1 were significantly decreased. C. kobomugi always had the lowest WUE among the three species in the field. It is therefore clear that I. anthephoroides is a heat‐resistant species, Calystegia soldanella is a heat‐enduring species and Carex kobomugi is a heat‐evading species due to its eraly phenology.
Seasonal change in the redox property of peat and its relation to vegetation in a system of floating mat and pond
Authors: Haraguchi Akira
Published: March 2006

A relationship was sought between species distribution and seasonal change in the redox property of peat in a floating mat in Mizorogaike Pond, central Japan. The mat surface experienced an annual submergence‐emergence cycle due to its sinking‐rising movement. Redox potential (Eh) of the surface peat showed little difference between communities in the mat in the submergence season (January–June) and early emergence season (July–August). However variation in Eh among communities was clear in the late emergence season (September–December). Among seven communities in the floating mat, the Menyanthes trifoliata‐Rhynchospora fauriei, M. trifoliata‐Eriocaulon sikokianum‐E. bondoense f. pilosum, Sphagnum cuspidatum and M. trifoliata‐Carex thunbergii communities had high Eh (400–600 mV) in the late emergence season, while the Menyanthes trifoliata and Phragmites australis‐M. trifoliata communities had lower Eh (200–400 mV). The M. trifoliata‐Isachné globosa community was intermediate (300–500 mV). The earlier the emergence of the peat surface began, the higher the Eh became in the late emergence season.
Roles of leaf water potential and soil‐to‐leaf hydraulic conductance in water use by understorey woody plants
Authors: Ishida Atsushi , Yamamura Yasuo , Hori Yoshimichi
Published: March 2006

Diurnal changes of leaf water potential and stomatal conductance were measured for 12 deciduous shrubs and tree saplings in the understorey of a temperate forest. Sunflecks raised the leaf temperature by 4°C, and vapor pressure deficit to 2 kPa. Although the duration of the sunflecks was only 17% of daytime, the photon flux density (PFD) of sunflecks was 52% of total PFD on a sunny summer day. Leaf osmotic potential at full turgor decreased in summer, except in some species that have low osmotic potential in the spring. Plants that endured low leaf water potential had rigid cell walls and low osmotic potential at full turgor. These plants did not have lower relative water content and turgor potential than plants with higher leaf water potential. There were three different responses to an increase in transpiration rate: (i) plants had low leaf water potential and slightly increased soil‐to‐leaf hydraulic conductance; (ii) plants decreased leaf water potential and increased the hydraulic conductance; and (iii) plants had high leaf water potential and largely increased the hydraulic conductance.