bluuebunny/crossref_metadata_2025_split huggingface dataset:
High speed nanophotonic devices based on quantum dots
Authors: Bimberg D. , Fiol G. , Kuntz M. , Meuer C. , Lämmlin M. , Ledentsov N. N. , Kovsh A. R. 
Published: November 2006

AbstractFor InAs‐GaAs based quantum dot lasers emitting at 1300 nm digital modulation with bit error rates below 10–11 at –2 dBm receiver power is demonstrated. Error rates of 10–9 or better are realized between 23 °C and 70 °C without current adjustment. Passive and hybrid mode‐locked QD lasers are shown to generate optical pulses with repetition frequencies up to 80 GHz and 40 GHz, respectively, with an ultra‐short minimum pulse length of 710 fs at 20 GHz. The minimum root mean square jitter of 40 GHz hybrid mode‐locked pulses is found to be 400 fs with a corresponding pulse width of 4 ps.Quantum dot based 1.3 µm fiber‐coupled amplifier modules show 40 Gb/s operation with bit error rates below 10–11. Amplifier chip gain up to 26 dB is demonstrated. 710 fs pulses are amplified without pulse broadening. For all devices we use deeply etched narrow ridge waveguide structures which show excellent current and optical confinement.Along with suppressed beam filamentation of the fundamental mode, a low α ‐factor and strongly reduced sensitivity to optical feedback our results demonstrate that QD laser performance is now comparable or even superior to quantum well lasers. These achievements became possible due to systematic devel‐opment of self‐organized growth technologies. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Special Issue: Frontiers in Semiconductor Nanoscience (Part A)
Authors: Bougeard Dominique , Finley Jonathan , Grayson Matthew , Tornow Marc 
Published: November 2006

AbstractThe present special issue of physica status solidi is dedicated to Professor Gerhard Abstreiter on the occasion of his 60th birthday. Guest edited by Dominique Bougeard, Jonathan Finley, Matthew Grayson, and Marc Tornow, it contains 24 papers covering different aspects of semiconductor physics and nanoscience. Additional contributions can be found in Part B published in phys. stat. sol. (b) 243, No. 14 (2006). Together the twin volumes of pss(a) and pss(b) cover many advanced topics, including quantum transport, optical properties and coherent phenomena, nano‐biological systems and novel materials and nanostructures.The cover picture shows a schematic image of a coupled quantum dot nanostructure formed by two‐fold cleaved edge overgrowth of a GaAs–AlGaAs heterostructure [1]. Such advanced nanostructure fabrication technologies were pioneered in Gerhard Abstreiter's group at the Walter Schottky Institut almost ten years ago. The molecular like electronic structure in such an artificial molecule remains subject to intense study even today in the context of solid‐state implementations of quantum information technologies. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
SC2: A Novel Process for Manufacturing Multipurpose High‐Density Chemical Microarrays
Authors: Dikmans Antonius , Beutling Ulrike , Schmeisser Edelgard , Thiele Sabine , Frank Ronald 
Published: November 2006

AbstractVarious formats of miniaturized arrays of cellulose‐bound synthetic probe molecules to suit a broad range of technical and assay configurations have been produced by a novel process which we call spotting compound‐support conjugates, SC2. This process involves parallel chemical assembly of the probe molecules by SPOT‐synthesis on a special cellulose membrane, post‐synthesis separation of the tethered compound spots, solubilization of the cellulose matrix and spotting of the soluble cellulose‐probe conjugates onto various types of planar surfaces. The performance of such arrays are demonstrated using a set of synthetic peptide analogues, assayed with a monoclonal antibody, as well as utilizing a small molecule library of diketopiperazines assayed with fluorescently labelled calmodulin.
Geometrical parameters, vibrational wavenumbers, and relationships established with six difluorobenzonitriles
Authors: Rastogi V. K. , Palafox M. A. , Singhal Surabhi , Ojha S. P. , Kiefer W. 
Published: November 2006

AbstractThe geometry, vibrational wavenumbers, and thermodynamical parameters have been calculated using density functional methods (DFT) for benzonitrile (BN) and the six difluorobenzonitriles (DFBNs) of the series. The results were compared with the available experimental data, and correlations were established for the CN and CF moieties between the natural atomic charges and the geometrical parameters of the compounds. These relations were found as linear or slightly parabolic in most cases. Investigations were carried out to examine the effect of substituents on structural deformations and other properties. Correlations were also determined with the stretching vibrations. Other general conclusions have also been drawn. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Placental shelf—a common, typically transient and benign finding on early second‐trimester sonography
Authors: Shen O. , Golomb E. , Lavie O. , Goldberg Y. , Eitan R. , Rabinowitz R. R. 
Published: November 2006

AbstractObjectivePlacental shelves are believed to represent circumvallate placentae. It is thought that circumvallate placenta may be associated with adverse perinatal outcome when present at delivery. The objective of this study was to determine the prevalence, persistence and significance of placental shelves detected in the early second trimester.MethodsIn 152 consecutive anomaly scans performed between 13 and 16 weeks of gestation, special attention was directed to placental structure and the presence of a placental shelf. When present, a mid‐gestation scan was performed to verify if the finding persisted. If so, a third‐trimester scan was performed. Delivery charts were reviewed for all cases initially diagnosed with a placental shelf, recording any placenta‐related complications.ResultsIn 17 of 152 (11.2%) early second‐trimester scans a placental shelf was detected. In three of these 17 cases the shelf persisted to the 20–22‐week scan. In the two cases that presented for the third‐trimester scan the shelf was no longer present. In all 17 cases the perinatal outcome was good.ConclusionsIn our study group early second‐trimester placental shelves rarely persisted to mid‐gestation and never to the third trimester. There were no placenta‐related perinatal problems. Early second‐trimester placental shelf appears to be a common, benign and transient sonographic finding. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Dynamics of age‐ and size‐structured populations in fluctuating environments: Applications of stochastic matrix models to natural populations
Authors: Nakaoka Masahiro 
Published: November 2006

AbstractRecent developments of the theory of stochastic matrix modeling have made it possible to estimate general properties of age‐ and size‐structured populations in fluctuating environments. However, applications of the theory to natural populations are still few. The empirical studies which have used stochastic matrix models are reviewed here to examine whether predictions made by the theory can be generally found in wild populations. The organisms studied include terrestrial grasses and herbs, a seaweed, a fish, a reptile, a deer and some marine invertebrates. In all the studies, the stochastic population growth rate (ln λs) was no greater than the deterministic population growth rate determined using average vital rates, suggesting that the model based only on average vital rates may overestimate growth rates of populations in fluctuating environments. Factors affecting ln λs include the magnitude of variation in vital rates, probability distribution of random environments, fluctuation in different types of vital rates, covariances between vital rates, and autocorrelation between successive environments. However, comprehensive rules were hardly found through the comparisons of the empirical studies. Based on shortcomings of previous studies, I address some important subjects which should be examined in future studies.
Interactions among fungal endophytes, grasses and herbivores
Authors: Clay Keith 
Published: November 2006

AbstractThe interaction between two species often depends on the presence or absence of a third species. One widespread three‐species interaction involves fungal endophytes infecting grasses and the herbivores that feed upon them. The endophytes are allied with the fungal family Clavicipitaceae and grow systemically in intercellular spaces in above‐ground plant tissues including seeds. Like related Claviceps species, the endophytes produce a variety of alkaloids that make the host plants toxic or distasteful to herbivores. A large number of grass species are infected, especially cool‐season grasses in temperate areas. Field and laboratory studies have shown that herbivores avoid infected plants in choice trials and suffer increased mortality and decreased growth on infected grasses in feeding experiments. Resistance to herbivores may provide a selective advantage to infected plants in competitive interactions with noninfected plants. Recent studies have shown that differential herbivory can reverse competitive hierarchies among plant species. Both endophyte‐infected and noninfected tall fescue grass (Festuca arundinacea) are outcompeted by orchardgrass (Dactylis glomerata) in the absence of insect herbivory. However, when herbivores are present infected tall fescue outcompetes orchardgrass. These results suggest that the frequency of infection in grass species and grassland communities will increase over time. Several studies are reviewed illustrating increases in infection frequency within grass populations subject to herbivore pressure. Endophytic fungi may be important regulators of plant‐herbivore interactions and so indirectly affect the structure and dynamics of plant communities.
Species richness and altitudinal variation in the aquatic metazoan community in bamboo phytotelmata from north Sulawesi
Authors: Sota T. , Mogi M. 
Published: November 2006

AbstractWe compared the aquatic metazoan community structure in bamboo stumps between a lowland (Kosinggolan; 200 m a.s.l.) and a highland site (Moat; 1030–1050 m a.s.l.) in North Sulawesi. The lowland bamboo stumps harbored 38 taxa including 2 predators, and the highland stumps harbored 35 taxa including 2 predators. In total 45 taxa were recorded, including 3 predators. Dominant detritivores were Tipulidae, Scirtidae, Chironomidae, Culicidae and Ceratopogonidae. The sole dominant predators wereToxorhynchitesmosquito larvae, which occurred in 67% and 28% of stumps at the lowland and the highland sites, respectively. Although the mean biomass per stump did not differ significantly between the sites, the mean number of species per stump was significantly smaller at the lowland site. In addition, the variation in species composition among stumps was greater at the lowland site than at the highland site. Among dominant taxonomic groups, the number of non‐predatory culicid species per stump was smaller at the lowland site where their predator,Toxorhynchites, was more abundant, although both sites had the same number of culicid species. In the presence ofToxorhynchites, the density and biomass of other culicids per stump were reduced significantly. The difference in predator density might affect differences in the local‐scale community structure of individual bamboo stumps.
Analysis of changes of insect‐plant ratio‐improvement of key‐factor analysis for evaluating bottom‐up effects in insect population dynamics
Authors: Yamada Yoshihiro 
Published: November 2006

AbstractA revised key‐factor analysis was presented for analyzing the temporal changes in the ratio of insect absolute number to plant resource. Ten data sets for 5 insect species were then analyzed. In this key‐factor analysis, the key factor is defined as the factor contributing highly to between‐year variation in Rr, the log rate of the inter‐year change of the insect‐plant ratio. The yearly change of plant resource was handled as a separate factor, expressed by rpl, log ratio of plant resource in year n to plant resource in year n+1. The following was revealed: 1) In 7 of the 10 data sets examined, rpl influenced variations of Rr; in particular in 3 cases rpl was the main key factor. 2) Generation‐to‐generation fluctuations of absolute insect densities showed density dependence in 4 cases, while those of insect‐plant ratios, in 8 cases. 3) The Royama model or a linear model, explained well the relationship between log insect‐plant ratio (Xr) and Rr and the relationship between Xr and log yearly change rate of absolute insect density (Rabs). However, in the 7 cases in which rpl was a critical factor for variations of Rr, with, increase of Xr,Rr showed a steeper, decrease around the equilibrium point (the point for which Rr is 0) than Rabs. This occurred because rpl tended to be negatively correlated with Xr. Consequently, in two cases Xr fluctuated cyclicly or chaotically although without the changes in plant resource, fluctuations of Xr would be damped oscillations approaching equilibrium.
Strain differences in the indian meal moth, Plodia interpunctella, in response to a granulosis virus
Authors: Boots Michael , Begon Michael 
Published: November 2006

AbstractThree strains of the Indian Meal Moth, Plodia interpunctella, were compared in terms of their response to a granulosis virus under different environmental conditions. A significant difference in the relative susceptibilities to the virus of the three laboratory strains was established. Evidence of potential trade‐offs with resistance was found in overall fecundity, pupal size and mortality at adult emergence. There was however little evidence that a reduction in resource level led to more trade‐offs being apparent. No clear relationship was found between resistance to the lethal effects of the virus and susceptibility to the sublethal effects of the virus.
Variable fortunes in a patchy landscape —The habitat templet of an insect migrant
Authors: Solbreck C. 
Published: November 2006

AbstractMigration by flight is essential for insects living in patchy landscapes and knowledge about variability in habitat patch structure and quality is important for the development of theory concerning insect dispersal polymorphisms. However, few studies provide more than anecdotal evidence about habitat change in time and space and its effects on insect survival and reproduction. Here I show how habitats and resource density of a lygaied bug, Lygaeus equestris, change in a patchy landscape over a seventeen year period. Although habitat patches per se are very stable, there are large temporal fluctuations in per capita food resources. Food seems to be limiting only in some years, and there may be periods of several years when populations change due to weather disturbance. Between‐patch variation in reproductive success is large. Furthermore, the relative favourability of patches changes between years. There are also distance effects; in some years distances to suitable hibernation sites affect reproductive success. Long fliers experience more variable success, and sometimes extreme success, when compared with short fliers. The importance of movements from outlying areas also changes with time. The insect is thus faced with a habitat templet which varies strongly on many temporal and spatial scales.
Inconstancy of Taylor's b: Simulated sampling with different quadrat sizes and spatial distributions
Authors: Sawyer Alan J. 
Published: November 2006

SummaryTaylor's power law, s2=amb, provides a precise summary of the relationship between sample variance (s2) and sample mean (m) for many organisms. The coefficient b has been interpreted as an index of aggregation, with a characteristic value for a given species in a particular environment, and has been thought to be independent of the sample unit. Simulation studies were conducted that demonstrate that the value of b may vary with the size of the sample unit in quadrat sampling, and this relationship, in turn, depends on the underlying spatial distribution of the population. For example, simulated populations with hierarchical aggregation on a large scale produced values of b that increased with the size of the sample unit. In contrast, for a simulated population with randomly distributed clusters of individuals, the value of b eventually decreased with increasing quadrat size, as sample counts became more uniform. A single value ofTaylor's b, determined with a particular sample unit, provides neither a fixed index of aggregation nor a complete picture of a species' spatial distribution. Rather, it describes a consistent relationship between sample variance and sample mean over a range of densities, on a spatial scale related to the size of the sample unit. This relationship may reflect, but not uniquely define, density‐dependent population and behavioral processes governing the spatial distribution of the organism. Interpretation ofTaylor'sb for a particular organism should be qualified by reference to the sample unit, and comparisons should not be made between cases in which different sample units were used. Whenever possible, a range of sample units should be used to provide information about the pattern of distribution of a population on various spatial scales.
Inheritance of sex ratio in the Kanzawa spider mite, Tetranychus kanzawai Kishida
Authors: Takafuji Akio , Ishii Toshio 
Published: November 2006

SummaryThe frequency distributions in sex ratios of offspring from 4 field Tetranychus kanzawai populations were examined. No significant difference was observed between average sex ratios of the 4 populations, although there was a great variability within each population, especially in the population from Pueraia lobata. Using the population from P. lobata, inbred lines with high (H) and low (L) sex ratios were selected. Crossing experiments between H and L showed that sex ratio is determined by the genotype of mothers. It seemed that sex ratio is cointrolled by several genes, with no cytoplasmic factor involved.
Phenological studies on the wing dimorphism of a semi‐aquatic bug, Microvelia douglasi (Heteroptera: Veliidae)
Authors: Muraji Masahiko , Miura Tadashi , Nakasuji Fusao 
Published: November 2006

SummarySeasonal changes in the percentage of macropterous individuals in natural population of Microvelia douglasi in permanent habitats were investigated in Shimane, western part of Japan. Macropterous forms of 5th instar nymphs occurred most frequently from late June to early July. However, the seasonal appearance of macropterous adults differed between habitats and years. There were significant effects of density, temperature, photoperiod and food availability on the percentage of macropters under laboratory conditions. The percentage of macropterous forms generally increased with density, but the mode of the response was modified by temperature, photoperiod and food availability. When insects were reared under long day photperiod (16L8D) with abundant food (0.5–1.0 g/container/day), the percentage of macroptery varied most among the different density treatments at the intermediate temperature (24°C) and the difference was reduced at higher temperature (28° and 32°C). Effects of temperature were small under the short day photoperiod (12L12D). Under 12L12D photoperiod sensitivity of density responses were higher at 32°C and lower at 24°C than those under 15L8D photoperiod. When the insects were supplied with food every other day, the density response became obscure. Ecological significance of environmental responses in the wing morph determination was discussed in relation to the heterogeneous environment of water surface.
Sibling and non‐sibling cannibalism by larvae of a lady beetle Harmonia axyridisPallas (Coleoptera: Coccinellidae) in the field
Authors: Osawa Naoya 
Published: November 2006

SummarySibling (cannibalism among siblings) and non‐sibling cannibalism (cannibalism among non‐siblings) were studied in a natural population of a lady beetle, Harmonia axyridisPallas.Of all the eggs laid (n=2269), 24.76% (n=562) were killed by sibling cannibalism and 36.10% (n=819) were killed by non‐sibling cannibalism. Sibling cannibalism occurred constantly and intensively in most egg batches throughout the entire oviposition period. On the other hand, non‐sibling cannibalism was more intense in the middle and late oviposition periods, and when the egg batches were close to an aphid colony. This may be due to the high density of H. axyridis larvae relative to aphid density in the middle and late oviposition periods and also the larvae searching intensively near an aphid colony.
Frequent successful multiparasitism by five parasitoids attacking the scale insect Nipponaclerda biwakoensis
Authors: Kaneko Shuji 
Published: November 2006

AbstractSuccessful multiparasitism by five parasitoid wasps of the scale insect Nipponaclerda biwakoensis was investigated at a reed bed in Lake Biwa. The wasps were gregarious endoparasitoids consuming the entire body of the host. The rate of successful multiparasitism for a parasitoid species was defined as the proportion of the number of individual hosts from which the species emerged with other species to the total number of hosts from which the species emerged. The rates were high for each parasitoid species, ranging from 17 to 82%. Successful multiparasitism frequently involved two species with similar adult size, but rarely involved species with different adult size. For four of the five species, the number of wasps per host was significantly less when wasps emerged from a host with other species relative to when emerged alone. For the other one species, the number of wasps was less, but the difference was not significant. With only one species, female wasps were significantly smaller when they emerged from a host with other species relative to when emerged alone.
Reproductive strategy of the sugi bark borer, Semanotus japonicus (Coleoptera: Cerambycidae) on Japanese cedar, Cryptomeria japonica
Authors: Shibata Ei'ichi 
Published: November 2006

AbstractThe inner bark of Japanese cedar, Cryptomeria japonica D. Don., is the main food of the sugi bark borer, Semanotus japonicus Lacordaire, but may also be involved in resistance to attack by the borer. I used newly hatched larvae to inoculate cedar logs that had been cut 2‐weeks to 12‐months earlier, and undamaged living cedar trees. On living trees, all larvae were killed by resin flow from the traumatic resin canals between the outer‐ and inner bark or between the inner bark and cambium. In logs that were cut more than 4 months prior to inoculation, larvae were unable to complete development. In logs cut 2 weeks prior to inoculation, almost all larvae were able to reach the adult stage but they were smaller in size than adults from living trees damaged by this borer. These results suggest that poor nutrient conditions in the inner bark of logs affected development and survival of the borer. Because of its nutritional advantage, living cedars provide a better environment for the sugi bark borer. However, all larvae are killed by resin flow, suggesting that this insect is “in between” being primary and secondary with respect to living trees, or a “weak” primary insect. The sugi bark borer seems to develop early in the season so that early instar larvae encounter reduced amounts of resin flow and so that late‐instar larvae feed mostly in summer when nutrient levels in the inner bark are at their highest.