bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new estimation method for the semiparametric accelerated failure time mixture cure model
Authors: Zhang Jiajia , Peng Yingwei 
Published: November 2006

AbstractThe 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

AbstractObjectivesTo identify important factors in the differential diagnosis of renal cysts associated with hyperechogenic kidneys.MethodsThis 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.ResultsOf 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.ConclusionRenal 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

AbstractObjectiveDespite 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 methodsFetuses 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.ResultsOf 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.ConclusionsThe 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

AbstractA 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

AbstractIntra‐ 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

AbstractNocturnal 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

AbstractClosely 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

AbstractAcoustic 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

SummaryTwo 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

SummaryIntra‐ 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

SummaryLarval 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

AbstractPlutella 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

ConclusionFrom 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 ConclusionPopulation 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

SummaryAnnual 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.