bluuebunny/crossref_metadata_2025 huggingface dataset:
Injection molding of syndiotactic polystyrene/clay nanocomposites
Authors: Sorrentino Andrea , Pantani Roberto , Brucato Valerio
Published: November 2006

This study aims at exploring the effect of a commercial organoclay montmorillonite (MMT) on the final properties of syndiotactic polystyrene (sPS) injection‐molded samples. To this goal, injection‐molded specimens made from neat sPS and commercial MMT modified with various organic compounds were prepared in different molding conditions. Dispersion of clay was attained via melt blending, directly in the injection chamber of the injection‐molding machine. The obtained specimens were analyzed by IR spectroscopy, X‐ray diffraction, thermogravimetry, and differential thermal analysis, with the aim of elucidating the effect of clay on the microstructures of the samples. Results clearly show that, depending on the organic modification, the presence of clay can induce strong effects on final crystallinity. This behavior can be attributed mainly to the role played by clay on the kinetics of the crystallization process. Eventually, it was found that the addition of a small percentage of clay (1%) in sPS can substantially widen the processing window of the material. POLYM. ENG. SCI. 46:1768–1777, 2006. © 2006 Society of Plastics Engineers.
Recycling of high impact polystyrene in coextruded sheet: Influence of the number of processing cycles on the microstructure and macroscopic properties
Authors: Soriano Florentino , Morales Graciela , de León Ramón Díaz
Published: November 2006

High impact polystyrene(HIPS) was repeatedly coextruded at 220°C, maintaining a constant composition of 70 wt% of virgin HIPS and 30 wt% of recycled HIPS. The gel content (GC), grafting degree (GD), swell index (SI), morphology of the rubber phase, and average molecular weight of the polystyrene (PS) matrix ($\bar{M}$w) were characterized after each processing cycle. The effect of these parameters on the melt flow index (MFI), the shear viscosity (η), the power law index (n), the Izod impact, and the stress at break were evaluated. The results demonstrated that the rheological properties changed with the number of processing cycles, e.g. the MFI decreased in the first cycle from 2.8 to 1.7 g/10 min, while from the second to the sixth cycle increased to 3.4 ± 0.2 g/10 min. The power law index increased from n = 0.29, after the first processing cycle, to n = 0.34 in the sixth cycle. The changes in MFI and n were attributed to changes in the physical structure of the rubber phase and to chain scissions in the PS matrix, caused by the recycling. Finally, the impact strength decreased with the increasing number of processing cycles, while the tensile stress at break remained constant. POLYM. ENG. SCI., 46:1698–1705, 2006. © 2006 Society of Plastics Engineers
Constitutive modeling for intercalated PMMA/clay nanocomposite foams
Authors: Jo Choonghee , Fu Jin , Naguib Hani E.
Published: November 2006

A constitutive model for tensile behavior of PMMA/clay nanocomposite foams was developed in this study. The elastic modulus of the nanocomposites is affected by the form of clays embedded in the polymer matrix. The reinforcing effect by intercalation of the clays and the detrimental effect by clay agglomeration were considered for the determination of the elastic modulus of the nanocomposites. A viscoelastic model was adapted for the tensile behavior of the material. The developed constitutive equation is expressed in terms of clay morphology and material properties. The aspect ratio of clays and the expansion of clay layer spacing in the intercalated clay clusters were proved to play a vital role in the reinforcing mechanism. For the verification of the constitutive model, Poly(methyl‐methacrylate) (PMMA)/clay nanocomposite foams were manufactured by batch process method and their uniaxial tensile test results were compared with theoretical predictions. Compared with the experimental results, the proposed constitutive equation showed agreement with the experimental test results. POLYM. ENG. SCI. 46:1787–1796, 2006. © 2006 Society of Plastics Engineers.
Pro‐inflammatory cytokines and depression in a familial cancer registry
Authors: O'Connor Mary‐Frances , Irwin Michael R. , Seldon Joyce , Kwan Lorna , Ganz Patricia A.
Published: November 2006

Patients undergoing cancer treatment (e.g., interferon or IL‐2 treatment) develop depression, and there is a positive relationship between their depression and circulating levels of proinflammatory cytokines. Depressed patients who are medically healthy also show increases in circulating markers of inflammation. The present study characterized baseline levels of inflammatory cytokine activity in 18 pairs of depressed and non‐depressed persons at high risk for cancer and matched for age, ethnicity and all unaffected by a personal history of cancer. Circulating levels of interleukin‐6 (IL‐6), soluble IL‐6 receptor (sIL‐6R), tumor necrosis factor‐α‐receptor (TNF‐RII), and soluble intercellular adhesion molecule (sICAM) did not differ between those with and without depression. The present data are important for characterizing persons at high risk for cancer who may later acquire knowledge of further increased risk through genetic testing. Copyright © 2006 John Wiley & Sons, Ltd.
Complementarity of hydrophobic properties in ATP‐protein binding: A new criterion to rank docking solutions
Authors: Pyrkov Timothy V. , Kosinsky Yuri A. , Arseniev Alexander S. , Priestle John P. , Jacoby Edgar , Efremov Roman G.
Published: November 2006

ATP is an important substrate of numerous biochemical reactions in living cells. Molecular recognition of this ligand by proteins is very important for understanding enzymatic mechanisms. Considerable insight into the problem may be gained via molecular docking simulations. At the same time, standard docking protocols are often insufficient to predict correct conformations for protein–ATP complexes. Thus, in most cases the native‐like solutions can be found among the docking poses, but current scoring functions have only limited ability to discriminate them from false positives. To improve the selection of correct docking solutions obtained with the GOLD software, we developed a new ranking criterion specific for ATP–protein binding. The method is based on detailed analysis of the intermolecular interactions in 40 high‐resolution 3D structures of ATP–protein complexes (the training set). We found that the most important factors governing this recognition are hydrogen‐bonding, stacking between adenine and aromatic protein residues, and hydrophobic contacts between adenine and protein residues. To address the latter, we applied the formalism of 3D molecular hydrophobicity potential. The results obtained were used to construct an ATP‐oriented scoring criterion as a linear combination of the terms describing these intermolecular interactions. The criterion was then validated using the test set of 10 additional ATP–protein complexes. As compared with the standard scoring functions, the new ranking criterion significantly improved the selection of correct docking solutions in both sets and allowed considerable enrichment at the top of the list containing docking poses with correct solutions. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Long‐wavelength (λ ≥ 1.3 µm) InGaAlAs–InP vertical‐cavity surface‐emitting lasers for applications in optical communication and sensing
Authors: Amann Markus‐Christian , Ortsiefer Markus
Published: November 2006

In this paper we present an overview of the properties and applications of long‐wavelength vertical‐cavity surface‐emitting lasers (VCSELs) based on the InGaAlAs–InP material system. With respect to significant temperature sensitivity of active material gain as well as insufficient thermal conductivity of InP‐based epitaxial compound layers, the effective thermal heat management appears as a major issue for application suitable device performance. In this context, the incorporation of a buried tunnel junction (BTJ) in connection with improved heat sinking resembles a breakthrough for long‐wavelength VCSELs. With the utilization of n‐type spreading layers and consequently ultralow series resistances, BTJ‐VCSELs exhibit sharply reduced excess heat generation. Furthermore, the BTJ‐approach enables self‐aligned optical and current confinement. A hybrid dielectric stack with Au‐coating yields an improved thermal heatsinking. The current status of BTJ‐VCSELs encompasses a number of superior performance values. At 1.55 µm wavelength, this includes room temperature single‐ and multimode continuous wave (cw) output powers of more than 3 mW and 10 mW, respectively, laser operation for heat sink temperatures well exceeding 100 °C, and optical data transmission rates up to 10 Gbit/s. The versatility of compound layer composition enables arbitrary emission wavelengths within a broad range of 1.3 and 2 µm. With respect to sensing applications, BTJ‐VCSELs appear as ideal components for optical detection of infrared active gases. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Self‐assembled Si and SiGe nanostructures: New growth concepts and structural analysis
Authors: Bauer G. , Schäffler F.
Published: November 2006

Self‐organization during strained‐layer heteroepitaxy has been a field of intense research in the last few years. Especially the Si/SiGe heterosystem is considered a model system for strain‐driven Stranski–Krastanow growth. In this review article, we concentrate on ordered Stranski–Krastanow growth of Ge and SiGe islands on prepatterned Si(001) substrates, which provide preferential nucleation sites. Perfectly ordered SiGe dot arrays in two and three dimensions are demonstrated, and the basic mechanisms for preferential nucleation in geometrically well‐defined etch pits are discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Directed graphs for the analysis of rigidity and persistence in autonomous agent systems
Authors: Hendrickx Julien M. , Anderson Brian D. O. , Delvenne Jean‐Charles , Blondel Vincent D.
Published: November 2006

We consider in this paper formations of autonomous agents moving in a two‐dimensional space. Each agent tries to maintain its distances toward a pre‐specified group of other agents constant and the problem is to determine if one can guarantee that the distance between every pair of agents (even those not explicitly maintained) remains constant, resulting in the persistence of the formation shape. We provide here a theoretical framework for studying this problem. We describe the constraints on the distance between agents by a directed graph and definepersistent graphs. A graph is persistent if the shapes of almost all corresponding agent formations persist. Although persistence is related to the classical notion of rigidity, these are two distinct notions. We derive various properties of persistent graphs, and give a combinatorial criterion to decide persistence. We also define minimal persistence (persistence with the least possible number of edges), and we apply our results to the interesting special case of cycle‐free graphs. Copyright © 2006 John Wiley & Sons, Ltd.
Beyond the “decorated landscapes” of educational reform: Toward landscapes of pluralism in science education
Authors: Mueller Michael P. , Bentley Michael L.
Published: November 2006

Perhaps, we are at the fork in the road when it is imperative that we consider whether the pursuit of pluralism in science education is a worthwhile endeavor in light of recent educational reforms that seem to decorate the true aim of education. The “decorated landscapes” of educational reform concentrate on economic growth and do little to promote the conservation of Earth's natural environments that sustain life itself. Here we renew a discussion of a 300‐year pursuit in the United States toward educational landscapes that contribute to students' lives. We connect with scholars who have pursued the pluralistic landscapes of culture in an attempt to make education more authentic and democratic and with scholars who have pursued an education for the conservation of the Earth's natural environments. We argue that these two educational domains are and necessarily should be reflective, reliant, and reciprocal of each other if we wish to truly engage students in scientific literacy—the authentic, relevant, and meaningful science education experiences that contribute a person's existence. Finally, we offer recommendations which aim to focus on the many meaningful landscapes that contribute to pluralistic life in science education. © 2006 Wiley Periodicals, Inc. Sci Ed 91:321–338, 2007
A comparison of mixed‐effects quantile stratification propensity adjustment strategies for longitudinal treatment effectiveness analyses of continuous outcomes
Authors: Leon Andrew C. , Hedeker Donald
Published: November 2006

The propensity adjustment is used to reduce bias in treatment effectiveness estimates from observational data. We show here that a mixed‐effects implementation of the propensity adjustment can reduce bias in longitudinal studies of non‐equivalent comparison groups. The strategy examined here involves two stages. Initially, a mixed‐effects ordinal logistic regression model of propensity for treatment intensity includes variables that differentiate subjects who receive various doses of time‐varying treatments. Second, a mixed‐effects linear regression model compares the effectiveness of those ordinal doses on a continuous outcome over time. Here, a simulation study compares bias reduction that is achieved by implementing this propensity adjustment through various forms of stratification. The simulations demonstrate that bias decreased monotonically as the number of quantiles used for stratification increased from two to five. This was particularly pronounced with stronger effects of the confounding variables. The quartile and quintile strategies typically removed in excess of 80–90 per cent of the bias detected in unadjusted models; whereas a median‐split approach removed from 20 to 45 per cent of bias. The approach is illustrated in an evaluation of the effectiveness of somatic treatments for major depression in a longitudinal, observational study of affective disorders. Copyright © 2006 John Wiley & Sons, Ltd.
A new estimation method for the semiparametric accelerated failure time mixture cure model
Authors: Zhang Jiajia , Peng Yingwei
Published: November 2006

The proportional hazard (PH) mixture cure model and the accelerated failure time (AFT) mixture cure model are usually used in analysing failure time data with long‐term survivors. However, the semiparametric AFT mixture cure model has attracted less attention than the semiparametric PH mixture cure model because of the complexity of its estimation method. In this paper, we propose a new estimation method for the semiparametric AFT mixture cure model. This method employs the EM algorithm and the rank estimator of the AFT model to estimate the parameters of interest. The M‐step in the EM algorithm, which incorporates the rank‐like estimating equation, can be carried out easily using the linear programming method. To evaluate the performance of the proposed method, we conduct a simulation study. The results of the simulation study demonstrate that the proposed method performs better than the existing estimation method and the semiparametric AFT mixture cure model improves the identifiability of the parameters in comparison to the parametric AFT mixture cure model. To illustrate, we apply the model and the proposed method to a data set of failure times from bone marrow transplant patients. Copyright © 2006 John Wiley & Sons, Ltd.
Differential diagnosis of fetal hyperechogenic cystic kidneys unrelated to renal tract anomalies: a multicenter study
Authors: Chaumoitre K. , Brun M. , Cassart M. , Maugey‐Laulom B. , Eurin D. , Didier F. , Avni E. F. ,   for the Groupe Radiopédiatrique de Recherche en Imagerie Foetale (GRRIF)
Published: November 2006

Objectives

To identify important factors in the differential diagnosis of renal cysts associated with hyperechogenic kidneys.

Methods

This was a retrospective multicenter study. We identified 93 fetuses presenting between 1990 and 2002 with hyperechogenic kidneys and which had a diagnosis of nephropathy confirmed later. We analyzed retrospectively the prenatal ultrasound findings of those fetuses which were found sonographically to have renal cysts.

Results

Of the 93 fetuses presenting with hyperechogenic kidneys and with a later diagnosis of nephropathy, there were 28 with autosomal dominant polycystic kidney disease (ADPKD), 31 with autosomal recessive polycystic kidney disease (ARPKD), 11 with Bardet–Biedl syndrome, nine with Meckel–Gruber syndrome, six with Ivemark II syndrome, one with Jarcho–Levin syndrome, one with Beemer syndrome and one with Meckel‐like syndrome. One third of the fetuses (30/93) had renal cysts. Cystic characteristics (size, location, number) were not very useful for diagnosis; more useful was diagnosis of an associated malformation. Three (11%) of the fetuses with ADPKD had cysts, as did nine (29%) of those with ARPKD, three (27%) of those with Bardet–Biedl syndrome, all (100%) of those with Meckel–Gruber syndrome, three (50%) of those with Ivemark II syndrome, and each of the three cases with other syndromes (Jarcho–Levin, Beemer and Meckel‐like syndromes). None of the cases with trisomy 13 had cysts. There were no associated malformations in the 12 cases with renal cysts and polycystic kidney disease; the other 18 cases with renal cysts were associated with malformations that were often specific, such as polydactyly in Bardet–Biedl and Beemer syndromes, occipital defect and Dandy–Walker malformation in Meckel–Gruber or Meckel–Gruber‐like syndromes, and thoracic and/or vertebral abnormalities in Jarcho–Levin and Beemer syndromes.

Conclusion

Renal cysts associated with hyperechogenic kidneys are not rare. The clue to diagnosis is the demonstration of an associated malformation. If no malformation is found, the main diagnosis remains polycystic kidney disease, i.e. ARPKD or ADPKD. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Imperforate anus: a relatively common anomaly rarely diagnosed prenatally
Authors: Brantberg A. , Blaas H.‐G. K. , Haugen S. E. , Isaksen C. V. , Eik‐Nes S. H.
Published: November 2006

Objective

Despite the relatively common occurrence of imperforate anus, prenatal diagnosis is rarely reported. In this study, we investigated the presence and diagnosis of imperforate anus along with strategies for improving prenatal diagnosis of the condition.

Patients and methods

Fetuses and infants with imperforate anus who had been examined prenatally by ultrasound at the National Center for Fetal Medicine (NCFM) from 1987 to 2004, were evaluated.

Results

Of 69 cases with imperforate anus, only 11 (15.9%) were diagnosed prenatally, at a median gestation of 18 + 4 (range, 15 + 6 to 35 + 6) weeks. In all 11, dilatations of the rectum or lower part of the bowel were seen. Additional anomalies, most of them diagnosed prenatally, were present in 59/69 (85.5%) of the cases. The most frequent additional anomalies were urogenital (53.6%). The karyotype was abnormal in nine cases (13.0%). A retrospective evaluation of available videotapes of 22 cases of imperforate anus that were not diagnosed prenatally revealed that it was possible to suspect the diagnosis in 11/22 (50%) cases. Sixteen infants were born with imperforate anus without prenatal diagnosis of any abnormality. In total, 31/69 (44.9%) cases were terminated, two (2.9%) died in utero and 12 (17.4%) died postnatally. Twenty‐four (34.8%) infants survived, including all 10 with isolated imperforate anus and seven of eight cases with only one additional anomaly.

Conclusions

The prenatal detection rate of imperforate anus was only 15.9%. Imperforate anus is often associated with other anomalies; in this study, 85.5% had additional anomalies. Prenatal diagnosis makes prenatal counseling possible and facilitates optimized postnatal care. We believe that the prenatal detection rate of imperforate anus could be improved. Examiners should intensify their search for typical findings of imperforate anus especially when other anomalies that frequently accompany this condition are present. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Fate of a mutant emerging at the initial stage of evolution
Authors: Xu Wei‐Zhong , Kashiwagi Akiko , Yomo Tetsuya , Urabe Itaru
Published: November 2006

A simple system was constructed and used in the experimental elucidation of the fate of a mutant emerging in a population. Three Escherichia coli strains having the same genetic background except for their glutamine synthetase gene were used as model competitors. The difference in the enzyme gene were introduced by random mutation. Competition between these bacterial strains was carried out and observed in a continuous liquid culture. In most cases, the competitors stably coexist either in a steady state or in an oscillating state. In addition, the competition between the strains was found to be a deterministic process and not a stochastic one. These results showed that an emerging mutant in a population, be it a closely related one to the original members, can attain a state of stable coexistence even in a homogeneous environment. The ability of each of the emerging mutants to maintain its stable coexistence with the original population gives rise to the accumulation of various mutants in a population. Therefore, evolution starts from gradual accumulation of various mutants in the population, which in turn leads to the diversification of the population. As our experimental system is a minimum model for the various competitions in the natural ecosystem, the observed competitive coexistence is proposed to be a general phenomenon in nature.
Inter‐ and intraspecific interactions among larvae of specialist and generalist parasitoids
Authors: Iwao Keisuke , Ohsaki Naota
Published: November 2006

Intra‐ and interspecific larval interactions that take place in a host body were investigated for two tachnid fliesEpicampocera succinctaandCompsilura concinnata(Diptera: Tachinidae) parasitizingPierisbutterfly larvae.E. succincta, a specialist onPierisbutterflies, showed contest‐type intraspecific competition, eliminating all the other conspecific larvae. On the other hand, an extreme generalist parasitoidC. concinnataexhibited scramble‐type competition, sharing the host with other conspecifics and suffering reduced body size as a result. However, when these two species occurred together in a single host,C. concinnatahad a much higher chance of survival. Moreover,C. concinnatacould often survive in the presence of a parasitoid waspCotesia glomerata(Hymenoptera: Braconidae) whileE. succinctacould not. The high tolerance ofC. concinnatacould be attributable to its being an extreme generalist: To attack and survive on many different hosts, one has to be able to deal with various competitors. The competitive inferiority of the specialistE. succincta, on the other hand, may be a result of relatively recent encounter with, those competitors.
Seasonality and vertical structure of light‐attracted insect communities in a dipterocarp forest in Sarawak
Authors: Kato Makoto , Inoue Tamiji , Hamid Abang Abdul , Nagamitsu Teruyoshi , Merdek Mahamud Ben , Nona Abdul Rahman , Itino Takao , Yamane Seiki , Yumoto Takakazu
Published: November 2006

Nocturnal flying insects were collected monthly for 13 months using ultra violet light‐traps set at various vertical levels in a weakly‐seasonal, tropical lowland dipterocarp forest in Sarawak, Malaysia. Abundance, faunal composition, size distribution and guild structure of these samples were analyzed with respect to temperal and vertical distributions. The nocturnal flying insect community in the canopy level was highly dominated by fig wasps (84%) in individual number, and by scarabaeid beetles (28%) in weight. A principal component analysis on monthly catches detected non‐random, seasonal trends of insect abundance. The first two principal trends were an alternation of wetter (September to January) and less wet seasons (February to August) and an alternation between the least wet (January to March) and the other seasons. Many insect groups were less abundant in the least wet season than the other seasons, whilst inverse patterns were found in Scarabaeidae and Tenebrionidae. Significantly positive and negative correlations between monthly catch and rainfall were detected only in ovule‐feeders and in phloem‐feeders, respectively. Delayed, significant negative correlations between monthly catch and 1–3 month preceding rainfall were more frequently detected in phytophages, phloem‐feeders, seed‐feeders, wood‐borers and scavengers. The peak in abundance along vertical levels were found at the canopy level (35 m) for phloem‐, ovule‐, seed‐, root‐, fungal‐feeders and nectar collectors, at an upper subcanopy level (25 m) for scavengers and aquatic predators, and at a middle subcanopy level (17 m) for ants. Catches at the emergent level (45 m) did not exceed those at the canopy level.
Coexistence and weak amensalism of congeneric gall‐forming aphids on the Japanese elm
Authors: Akimoto S.
Published: November 2006

Closely related species of gall‐forming aphids are often associated with a single host species. Six Tetraneura species coexist on the Japanese elm, Ulmus davidiana, in Sapporo, northern Japan. This paper describes the probabilities of coexistence on macro‐ and microgeographic scales (i.e., on host trees and host leaves) and examines whether coexistence with conspecific or heterospecific galls on leaves or shoots has any effect on the fecundity of each aphid species using multiple regression. A Monte Carlo simulation showed that the frequency distribution of the numbers of species on individual host trees differed significantly from that expected from the null model. There were significantly positive or negative associations between species. Tetraneura radicicola and sorini always coexisted with other species on trees they infested. Multiple regression revealed that the coexistence of conspecific or heterospecific galls on individual leaves had no influence on the fecundity of radicicola and sorini, but had a negative influence on that of sp. O. On average, radicicola and sorini produced a smaller number of offspring in galls than sp. O, and obviously consumed only a small part of resources available on the galled leaves. Evidence available suggests that although amensalism does arise between sp. O and other species, its influence in not so strong as to exclude sp. O competitively from the Tetraneura community.
Genetic control and evolution of acoustic signals in planthoppers (Homoptera: Delphacidae)
Authors: De Winter A. J.
Published: November 2006

Acoustic signals are part of the specific mate recognition system of planthoppers. The genetic control of acoustic signal characters was studied in the planthopperRibautodelphax imitans. Artificial selection for interpulse interval in the female call revealed a large additive genetic component for this polygenic character. Other female call characters showed a correlated response. Some male call characters also appeared to be genetically correlated with the female character selected for, despite the rather different structure of male and female calls. Parent‐offspring regression provided significant heritability estimates for those male call characters that also responded to artificial selection in the female call, one of which appeared to be influenced by sex‐linked genes. It is argued that the differentiation of this mate recognition system in planthopper populations and species could be the result of founder effects, enabled by the genetic plasticity of the call characters and the existence of a wing length dimorphism in these animals.
Survivorship and fertility schedules of two Sumatran tortoise beetles, Aspidomorpha miliaris and A. sanctaecrucis (Coleoptera: Chrysomelidae) under laboratory conditions
Authors: Nakamura Koji , Abbas Idrus , Hasyim Ahsol
Published: November 2006

Two species of tortoise beetles, Aspidomorpha miliaris (AM) and A. sanctaecrucis (AS) feeding on a shrub‐like morning glory, Ipomoea carnea, were reared under laboratory conditions to study their survivorship and fertility schedules. AM and AS required 34–39 days and 30–37, respectively, for the development of the immature stages. The mean longevity of the males was 88.4 days in AM and 63.8 in AS, and that of females was 87.9 days in AM and 83.3 in AS. The mean length of the pre‐reproductive period (27.2 days in AM and 33.8 in AS) was much longer than that of the post‐reproductive period (10.9 days in AM and 14.3 in AS). Females laid eggs at a nearly constant rate throughout their reproductive period. The reproductive value Vx/V0 of the two species remained high for most of their adult life, as a result of prolonged survivorship and fertility periods. The total number of eggs produced per female was 442.9 (AM) and 80.1 (AS). The intrinsic rate of natural increase r was 0.070 (AM) and 0.044 (AS) per capita per day. The prolonged reproductive schedules, coupled with strong dispersal power, of these species no doubt have an adaptive value for living in highly disturbed tropical environments, where rainfall is ample but unpredictable and food resources are available throughout the year in a wide area, but distributed in widely flung patches.
Competition between laboratory populations of green leafhoppers, Nephotettix spp. (Homoptera: Cicadellidae)
Authors: Valle Reynaldo R. , Kuno Eizi , Nakasuji Fusao
Published: November 2006

Intra‐ and interspecific competition between laboratory populations of four green leafhoppers, Nephotettix spp. was studied in the laboratory under three different temperature regimes of 24°C, 27°C and 30°C. For the single‐species population of the three tropical species, the equilibrium density increased as the temperature increased. On the other hand, for the temperature species N. cincticeps, the highest equilibrium density was at the intermediate temperature and the lowest at high temperature.

Interspecific interactions between two tropical (N. virescens vs. N. nigropictus), a tropical and a temperature (N. virescens vs. N. cincticeps) and a rice‐feeding and a grass‐inhabiting (N. virescens vs. N. malayanus) Nephotettix species were also studied in the laboratory at the three temperature regimes. Temperature differentially affected the outcome of competition between two Nephotettix species. Between N. virescens and N. nigropictus, the latter was more successful over the former at low and intermediate temperatures, while the former was more successful at high temperature. Between N. virescens and N. cincticeps, the temperate species inhibited the growth of the tropical species at low temperature while the tropical species inhibited the growth of the temperate species at high temperature. At intermediate temperature, the population of N. virescens persisted at a slightly higher density over the population of N. cincticeps. Between the rice‐feeding N. virescens and the grass‐inhabiting N. malayanus, regardless of temperature the population density of the latter was greatly reduced and later became extinct while the population of the former continued its growth. These consequences of competition between two Nephotettix species conformed fairly well to those predicted by theLotka‐Volterra model using demographic parameters specified for each species.
Larval growth dynamics of Hemipyrellia ligurriens (Calliphoridae) and Boettcherisca formosensis (Sarcophagidae) in crowded and uncrowded cultures
Authors: So Ping‐Man , Dudgeon David
Published: November 2006

Larval growth patterns of Hemipyrellia ligurriens (Calliphoridae) and Boettcherisca formosensis (Sacophagidae) in crowded and uncrowded cultures were compared. Growth of the larvae followed a sigmoid curve. The highest larval growth rates were 0.33 and 0.36 mg h−1 for uncrowded and crowded H. ligurriens respectively. The corresponding figures were 2.38 and 1.23 mg h−1 for B. formosensis. Larvae of both species attained maximum weight earlier in crowded cultures than in uncrowded cultures, although the final weights attained in crowded cultures were less. The earlier period of most rapid growth in both species was interpreted as a result of intraspecific facilitation at higher larval densities. Uncrowded B. formosensis had a shorter larval to pupal development and an earlier period of most rapid growth than uncrowded H. ligurriens, suggesting the former may be superior in exploiting carcasses with limiting food.
Longevity, flight ability and reproductive performance of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Yponomeutidae), related to adult body size
Authors: Shirai Yoichi
Published: November 2006

Plutella xylostella in the temperate zone shows a clear seasonal change in adult body size. In the laboratory, large and small moths were produced during immature stages at 15°C and 25°C, respectively. These moths were then used to evaluate longevity, age‐specific flight ability, flight ability of mated and unmated females, and the influence of flight experience on the subsequent reproductive success. The large moths lived longer and displayed a greater flight ability over 3 weeks. Irrespective of body size, unmated females flew for a longer time than mated females, and flight experience affected their subsequent reproductive success. Females of both sizes mated and laid eggs soon after emergence, without any obvious pre‐reproductive period. More flight experience did not delay oviposition, but did reduce egg production. It is likely that large moths with a longer adult life span and greater flight ability are better fitted for long‐distance flight and more fecund than small ones. These experimental results may explain why long‐distance migration of P. xylostella is mostly seen during cool seasons, when relatively large moths with long forewing appear in the field.
A possible discrepancy between the exposed and the whole population depending on range‐size and trap‐spacing in vole populations
Authors: Tanaka Ryo
Published: November 2006

Conclusion

From a field study for the vole population (Clethrionomys rufocanus) in Hokkaido in the late summer of 1965, it has been proved that the range length may decrease from 25 to 18 m by the gross along with the rise from 20 to 100 in the density level per acre, and hence that an appreciable discrepancy, due to underestimation, may be produced in estimates of the exposed as compared to the whole population at an outbreaking density as high as 100 on a plan with trap‐spacing 10 m.

In consideration of this together with my preceding results, the strict terms that we may enough approximate the whole one by estimating the exposed seem likely to be that the ratio of range radius to trap spacing, supposing a range is circular, should be near 2 or more at either ordinary or outbreaking densities, to say in the concrete, that the trap spacing as close as 5 m or so in grid is desirable with this vole, perhaps with most other voles.
Population dynamics of the Smith's red‐backed vole in highlands of Shikoku
Authors: Tanaka Ryo
Published: November 2006

Summary and Conclusion

Population dynamics of theSmith's red‐backed vole predominantly common through uplands of Shikoku have been in some degree disclosed by the use of my own and Government Forest Station's samples collected since 1955 onward.

It has proved that the upper‐range population reaches its density peak possibly in late summer or early fall, but the lower‐range one does probably in October–November as the seasonal trend in usual years. The upper one produced a peak three times at 3–4 year intervals, the first peak being an outbreak followed by a crash, during the last decade. It seems likely that all the populations through the range have, in the gross, fluctuated in phase after 1959 at least. The cyclic fluctuation may readily be explained by the theory of intrinsic mechanism, because no external factors are considered to have exerted a conclusive effect.

Except what was concerned in the outbreak, the role of the social stress could be set at naught.

The regulation of fecundiy by density was expressed more markedly in litter size and less in active reproductivity rate and incidence of pregnancy.

The mean litter size at term as small as 2.00 is contrary to our expectation in view of the supposed prolific potential, nevertheless the observed frequency of litter poduction and intra‐uterine survival rate has proved not to be so high as to make up for the small litter size. The problem in the postnatal mortality has remained to be solved.
Population fluctuations and natural mortalities of the pine‐moth, Dendrolimus spectabilis
Authors: Kokubo Atsushi
Published: November 2006

Annual changes in the population of the pine‐moth, Dendrolimus spectabilisButler, were studied in Kashima district. The insect completes two generations in one year, and the adult emerges in early summer and again in autumn.

The insect population showed fairly drastic fluctuations in the past years, and a conspicuous peak was recorded in three times, in 1950, 1955 and 1961. It was noted in each of those three years that a great number of adults of the summer generation emerged in autumn. The main reason for this great abundance of the insect population seemed to be high survival rate of the young larvae in summer. It was suggested that the climate in July had powerful influence upon the survival f thos e young larvae.

The effects of natural enemies were usually the greatest on the egg population of the pine‐moth in either generation. Much greater number of insects in the overwintering generation was destroyed by parasites and diseases than in the summer generation. Finally, a rapid increase of the insect population in autumn was considered to be caused by a combined effect of climatic conditions and of natural enemies.
Distribution of Mogannia minutamatsumura (Homoptera: Cicadidae) in the Island of Okinawa: Expansion of distribution range during five years
Authors: Itô Yosiaki , Nagamine Massaki
Published: November 2006

A five‐year study on the microgeographical distribution pattern of a sugarcane cicada, Mogannia minuta (=iwasakii), in the Island of Okinawa revealed that the trapezoid type distribution was an unique feature of the distribution of this species. The rate of expansion of the distribution range was remarkably small despite the continuous occurrence of sugarcane plants. These facts can be explained well by the theory of escape. That is, the epidemic cicada populations should be free from predation pressure in the infested area, but those in peripheral zones could be eradicated by predators. The possible role of regulatory factor(s) which suppress further increase in the density in the infested area was suggested.
Computer simulation study on the cyclicities of Tribolium population dynamics
Authors: Fujii Koichi
Published: November 2006

Under a set of assumptions, a mathematical model was constructed to investigate the effect of cannibalistic behavior and medium renewal schedule on Tribolium population dynamics, and the results of simulation analyses were presented to show how modelling can contribute to a better understanding of experimental study.

The analyses of the present model, the main concern of which is the cyclicity in Tribolium population. showed that there are two distinct factors which create cyclicity, the cannibalistic behavior in Tribolium itself, and the medium renewal schedule. Cannibalism per se does not necessarily cause cyclicity, but the combinations of cannibalistic behavior among various life stages and their relative intensities among them can cause cyclicity and can also determine the period of cycle. External factors also can generate cyclicity, but their interaction with cannibalistic behavior has a more significant effect in modifying the period of cycle.

Some discrepancies between the model and experimental results were discussed.
Ecological studies on a dragonfly, Nannophya pygmaea ramber (Odonata: Libellulidae) I. seasonal changes of adult population and its distribution in a habitat
Authors: Fujita Kazuyuki , Hirano Koji , Kawanishi Michiharu , Ohsaki Naota , Ohtaishi Makoto , Yano Eizi , Yasuda Makoto
Published: November 2006

Adult population of a dragonfly Nannophya pygmaeaRamber inhabited in a damp ground was investigated with mark‐and‐recapture method in 1975. The following results about the seasonal changes of the population size and distribution in the habitat were obtained.

Adults emerged from late May to mid August. The number of the adults was most abundant in early June, but that of matured males in early July. From the recapture data, the estimate of daily survival rate was 0.82, and the length of immature stage in males was estimated as 5 days or so. Total number of post‐teneral adults emerged in the habitat was estimated as about 9,000. The mean crowding‐mean density regression method was applied for the analysis of the distribution pattern of the adults. Matured males showed a spaced‐out distribution, while females and immatured males distributed themselves rather aggregatively. Such a distribution pattern of the matured male would be attributed to their territorial behaviour. The territorial behaviour was considered to force the matured males to extend the distribution area in July when they were most abundant.

From the above‐mentioned results and some observations, the meaning of the territoriality in this species was discussed.
Distribution pattern of groundfishes hooked along a row of setline in the shallower part of the continental slope in the Bering Sea 2 bathymetric difference in relative abundance in relation to distribution pattern
Authors: Maéda Hiroshi
Published: November 2006

Summary and Conclusion

This report demonstrates the well‐defined bathymetric distribution of relative abundance of groundfishes in relation to the distribution pattern conjectured from the records of catch along a row of setline with remarkably large variation in the settled depth (from shallower than 350 m to deeper than 700 m) observed around 580 18′ N and 1750 28′ W on Aug. 24, 1962.

The results of the analyses are depicted in Fig. 1. It is found that halibut, true cod and Sebastodes sp. (or Menuke in Japanese) show sharp or abrupt decrease in the relative abundance in accordance with depth whereas sablefish and rattail increase sharply. Arrow toothed halibut and ray do not show any clear bathymetric change in relative abundance and Pacific ocean perch shows decrease in the density in accordance with the disparity in the depth from the 500 m isobath.

The patterns conjectured from this example are compared with either those shown in other reports, the results of the observations on other examples or general view of our fishermen. And many proofs to the high reliability and wide universality of the conjectured pattern of the first four species are found out. But, for the last three species, the present results differ more or less from the general view of our fishermen and the observations on other examples.

For the distribution pattern, most of groundfishes incline to show chance distribution in the shallower part of the continental slope (350 m to 700 m deep) and only the species showing sharp decrease in density with increase in the depth are distributed contagiously on the shallower bottom (not deeper than 450 m).
A note on the estimation of selective values from recaptures of marked animals when selection pressures remain constant over time
Authors: Manly B. F. J.
Published: November 2006

An equation is given for the estimation of selective values from data obtained by mark‐recapture experiments, assuming that selective pressures remain constant while the experiments are carried out. The equation does not have an explicit solution but can readily be solved using a trial‐and‐error method.

The use of the equation is illustrated on some data reported byKettlewellet al. (1969) from an experiment involving typica and edda morphs of the moth Amathes glareosa. It is found that the edda morph apparently had a selective advantage of about 12% per day compared to the typica morph and that this is significantly different from zero. Using another methodKettlewell concluded that the selective advantage of the edda morph was only 7% and that this was not statistically significant.
On an outbreak of the citrus flat‐headed borer, Agrilus auriventrisE. Saunders in Nagasaki Prefecture
Authors: Ohgushi Ryoh‐ichi
Published: November 2006

The process of an outbreak of the citrus flat‐headed borer, Agrilus auriventris in Nagasaki Prefecture was described with some ecological considerations on causative factors.

This outbreak which showed a typical “Gradation”, initiated around 1958, and terminated in 1963. The peak year was seen in 1961. At first attack by the borer was restricted to old and weak trees, but it was also found in young and healthy trees in the peak year.

Some environmental conditions in orchards were examined in relation to the intensity of infestation by the borer. Soil management and drought seemed to have remarkable correlations with the borer's infestations.

Probably, this outbreak was caused by the weakening of citrus tree by gummosis and abnormal defoliation, aging of orchard trees, and drought in the summer of 1959∼1960. Interrelation between these causes and processes are shown schematically in Fig. 12.
Parameter estimates from mark‐recapture experiments on two populations subject to migration and death
Authors: Neil Arnason A.
Published: November 2006

A model is developed for a triple catch marking experiment on two areas with migration between the two areas and death or emigration occurring. Estimates of the parameters of the model are derived. Some of these estimates are shown to be suitable even under certain restrictions on migration (e.g. animals may be restricted to a single transfer in the course of the experiment). Variances of the estimates were not derived but some rules were developed, based on computer simulations, to guide the experimenter in planning experiments and in judging the precision of his estimates.
Demographic traits of understory trees and population dynamics of a Picea‐Abies forest in Taisetsuzan National Park, northern Japan
Authors: Kubota Yasuhiro
Published: November 2006

The size structure transition matrices of Picea jezoensis, Picea glehnii and Abies sachalinensis of a sub‐boreal forest in Hokkaido, northern Japan were constructed based on the demography of each species (Picea jezoensis and Picea glehnii were dealt with together as Picea) during a 4‐year period. Two types of matrices, density‐independent and density‐dependent population dynamics models, were investigated for evaluating the ‘waiting pattern’ between Picea spp. and A. sachalinensis. For the density‐dependent model, it was assumed that the demographic traits of understory trees, the recruitment rate, the understory mortality rate and the transition probability from the understory to canopy stages, were regulated by the one‐sided competitive effect of canopy trees. The observed size structure of Picea was almost consistent with the stationary size structure obtained in both the density‐independent and the density‐dependent models, whereas the observed size structure of A. sachalinensis was not realized in the two models. The effects of both the transition probability from the understory to canopy stages and the recruitment rate on the dynamics of canopy trees were investigated. For Picea, two parameters—recruitment rate (ei) and transition probability from the understory to canopy stages‐exponentially affected the dynamics of canopy trees. In contrast, for Abies sachalinensis, the two parameters affected linearly the dynamics of canopy trees. In conclusion, the population dynamics of Picea and A. sachalinensis was determined by the parameters of the recruitment rate and the transition probability from the understory to canopy stages, relating to waiting patterns of understory trees for future gap formation. In Picea, the demographic parameters of understory trees intensively regulated the dynamics of canopy trees if compared with A. sachalinensis, suggesting that the performance of understory trees plays a key role in the population dynamics of Picea. This reflects the growth pattern of understory trees in the regeneration of the two species.