bluuebunny/crossref_metadata_2025_split huggingface dataset:
Socio‐economic disparities in preterm birth: causal pathways and mechanisms
Authors: Kramer Michael S. , Goulet Lise , Lydon John , Séguin Louise , McNamara Helen , Dassa Clément , Platt Robert W. , Fong Chen Moy , Gauthier Henriette , Genest Jacques , Kahn Susan , Libman Michael , Rozen Rima , Masse André , Miner Louise , Asselin Guylaine , Benjamin Alice , Klein Julia , Koren Gideon 
Published: March 2003

Preterm birth is the leading cause of infant mortality in industrialised societies. Its incidence is greatly increased among the socially disadvantaged, but the reasons for this excess are unclear and have been relatively unexplored. We hypothesise two distinct sets of causal pathways and mechanisms that may explain social disparities in preterm birth. The first set involves chronic and acute psychosocial stressors, psychological distress caused by those stressors, increased secretion of placental corticotropin releasing hormone (CRH), changes in sexual behaviours or enhanced susceptibility to bacterial vaginosis and chorioamnionitis, cigarette smoking or cocaine use, and decidual vasculopathy. The second hypothesised pathway is a gene–environment interaction based on a highly prevalent mutation in the gene for methylenetetrahydrofolate reductase (MTHFR), combined with low folate intake from the diet and from prenatal vitamin supplements, consequent hyperhomocysteinemia, and decidual vasculopathy.We propose to test these hypothesised pathways and mechanisms in a nested case‐control study within a prospectively recruited and followed cohort of pregnant women with singleton pregnancies who deliver at one of four Montreal hospitals that serve an ethnically and socio‐economically diverse population. Following recruitment during the late first or early second trimester, participating women are seen at 24–26 weeks, when a research nurse obtains a detailed medical and obstetric history; administers several scales to assess chronic and acute stressors and psychological function; obtains blood samples for CRH, red blood cell and plasma folate, homocysteine, and DNA for the MTHFR mutation; and performs a digital and speculum examination to measure cervical length and vaginal pH and to obtain swabs for bacterial vaginosis and fetal fibronectin. After delivery, each case (delivery at < 37 completed weeks following spontaneous onset of labour or prelabour rupture of membranes) and two controls are selected for placental pathological examination, hair analysis of cotinine, cocaine, and benzoylecgonine, and analysis of stored blood and vaginal specimens. Statistical analysis will be based on multiple logistic regression and structural equation modelling, with sequential construction of models of potential aetiological determinants and covariates to test the hypothesised causal pathways and mechanisms.The research we propose should improve understanding of the factors and processes that mediate social disparities in preterm birth. This improved understanding should help not only in developing strategies to reduce the disparities but also in suggesting preventive interventions applicable across the entire
Abdominal wall defects in Denmark, 1970–89
Authors: Bugge M. , Holm N. V. 
Published: March 2003

SummaryIn the last two to three decades, increasing rates of gastroschisis but not of omphalocele have been reported from different parts of the world. The present study represents a register containing 469 children born with abdominal wall defects based on data retrieved from 20 birth cohorts (1970–89) in three nationwide registries. A tentative estimate of the completeness as regards identification of liveborn and stillborn infants is a minimum of 95% and 90% respectively. All cases were reclassified to 166 cases of gastroschisis, 258 of omphalocele and 16 of gross abdominal wall defect. The average point prevalence at birth of gastroschisis was 1.33 per 10 000 live and stillbirths. During the first decade, an increase in prevalence occurred culminating in 1976, followed by a decrease reaching its initial value in 1983 and then a new increase. Overall, no significant linear trend could be demonstrated for the entire period. The average point prevalence at birth for omphalocele was 2.07 and for gross abdominal wall defect 0.12 per 10 000 live and stillbirths with no significant change in the period. The geographical distribution of gastroschisis and omphalocele showed no difference per county.
The reproductive health of daughters of pregestational diabetic women: Medical Birth Registry of Norway
Authors: Egeland Grace M. , Skjærven Rolv , Irgens Lorentz 
Published: March 2003

SummaryMaternal diabetes may have an impact upon a daughter's reproductive health through genetic influences, an altered fetal metabolic environment or both. We examined the reproductive health of daughters of diabetic women using linked generation data from the Medical Birth Registry of Norway. Among all female births between 1967 and 1982 (n = 459 182), 739 had a mother with registered pregestational diabetes, a rate of 1.6 per 1000 deliveries. A total of 142 904 daughters delivered at least one child by 1998. After taking into account differences in survival, we observed no differences in the percentage of childbearing and in the average number of children born by 1998 between daughters with and without a diabetic mother in age‐stratified analyses. In analyses limited to singleton deliveries and stratified by mothers’ and daughters’ diabetic status, we found a threefold excess stillbirth delivery rate among women who had either a mother with pregestational diabetes (2.6%) or pregestational diabetes themselves (2.6%) compared with the stillbirth delivery rate observed in non‐diabetic women with no maternal history of diabetes (0.8%). These findings were unaltered in multivariable analyses adjusting for daughters’ maternal age and registered obstetric risk factors. Our results indicate that pregestational diabetes remains a health care challenge in Norway and that further evaluation of the reproductive health of daughters of diabetic pregnancies is warranted.
Reducing the caesarean delivery risk in elective inductions of labour: a decision analysis
Authors: Bailit Jennifer L. , Downs Stephen M. , Thorp John M. 
Published: March 2003

SummaryTo determine whether the vaginal delivery rate is increased in nulliparous women who have positive fetal fibronectin (fFN) testing before elective induction of labour, we performed a decision analysis that tested three options: (1) spontaneous labour; (2) testing nulliparous candidates for elective induction of labour at 39 weeks gestation with fFN and inducing labour if fFN positive (women who are fFN negative are managed expectantly); (3) elective induction of labour for women who are at least 39 weeks. We found that spontaneous labour had a vaginal delivery rate of 90%, elective induction 79% and fFN screening 83%. At baseline, a mother must be willing to take an additional 7% risk of caesarean delivery to warrant fFN testing or an additional 11% risk of caesarean delivery to warrant elective induction. We conclude that spontaneous labour has the highest vaginal delivery rates. An fFN test in a nulliparous woman may help to raise her likelihood of a vaginal delivery in an elective induction.
Breast feeding and cognitive development in childhood: a prospective birth cohort study
Authors: Oddy Wendy H. , Kendall Garth E. , Blair Eve , De Klerk Nicholas H. , Stanley Fiona J. , Landau Louis I. , Silburn S. , Zubrick Stephen 
Published: March 2003

SummaryThe aim of this study was to examine prospectively the relation between duration of breast feeding and cognitive outcomes. A cohort study of 2860 children enrolled before birth provided data from 2393 term infants of English‐speaking mothers. Of these, complete infant feeding data in the first year of life and verbal cognitive IQ (Peabody Picture Vocabulary Test – PPVT‐R) were available for 1450 children at 6 years, and a performance subtest (Perceptual organisation WISC – Block Design) for 1375 children at 8 years. Full breast feeding was categorised as none,> 0 to < 4 months, 4–6 months and> 6 months. Associations between breast‐feeding duration and PPVT‐R at 6 years and Block Design at 8 years were estimated before and after adjustment for gender, gestational age, maternal age, maternal education, parental smoking and the presence of older siblings.The early cessation of full breast feeding was associated with reduced verbal IQ and the performance subtest. In unadjusted analysis, mean standardised PPVT‐R scores were 6.44 points greater (P < 0.0001) in children fully breast fed for> 6 months compared with those never breast fed. After adjustment, mean PPVT‐R scores were 3.56 points higher in children fully breast fed for> 6 months compared with those children never breast fed (P = 0.003). Similarly, Block Design scores were higher in those fully breast fed for> 6 months compared with those never breast fed in unadjusted (P = 0.001) but not adjusted analyses (P = 0.223). Interactions between maternal education (four levels) and breast feeding demonstrated a positive association of maternal education on verbal IQ (F = 2.64; P = 0.005) in children breast fed for longer but not on performance (F = 0.74; P = 0.67). The early introduction of milk other than breast milk was associated with reduced verbal IQ after adjustment for social and perinatal confounders. Although these effects were interacting with maternal education, they may act through undefined mechanisms in human milk.
Electrophysiological response to herbivore‐induced host plant volatiles in the moth Spodoptera littoralis
Authors: Jönsson M. , Anderson P. 
Published: March 2003

AbstractIn cotton, Gossypium hirsutum (Malvacae), the volatiles emitted from the plant change in response to herbivory. Ovipositing females of the Egyptian cotton leaf worm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) can discriminate between cotton plants subjected to larval feeding and undamaged plants during oviposition. In this study we investigate whether females of this moth can detect the herbivore‐induced cotton volatiles. The response of female S. littoralis antennae to volatiles collected from cotton plants subjected to larval feeding was studied using GC‐EAD (coupled gas chromatography electroantennographic‐detection). By GC‐EAD, responses to over 10 different cotton volatiles were observed. Using single sensillum technique the responses of short sensilla trichodea on the antennae of S. littoralis females to 19 cotton volatiles and 12 general plant volatiles were investigated. Responses to these volatiles were recorded from 108 receptor neurones. Several neurones activated by herbivore‐induced cotton volatiles were recorded. For example, a neurone type responding to two homoterpenes [(E,E)‐4,8,12‐trimethyl‐1,3,7,11‐tridecatetraene and (E)‐4,8‐dimethyl‐1,3,7‐nonatriene] and (E,E)‐α‐farnesene was frequently found. We also observed sensitive neurones responding specifically to the herbivore‐induced volatiles (+/–)‐linalool and indole. In general, a stimulus load of less than 1 ng was needed to activate these neurones. In addition, specific neurones were found for constitutive cotton volatiles released in connection with damage to the plant. An abundant neurone type responded to β‐caryophyllene and α‐humulene. Another neurone type responded specifically to the non‐induced cotton volatile (Z)‐jasmone. These results show that females of S. littoralis have receptor neurones that would make it possible to discriminate between damaged and undamaged plants using volatile signals.
An analysis of the pattern of feeding in the Costa Rican weevil, Exopthalmus jekelianus, on the tropical tree, Cedrela odorata
Authors: Wright G. A. , Raubenheimer D. , Simpson S. J. 
Published: March 2003

AbstractFeeding patterns were recorded and analysed for adult female weevils, Exopthalmus jekelianus (White) (Coleoptera: Curculionidae), feeding on Central American mahogany, Cedrela odorata L., in the field in Costa Rica. The study forms part of an investigation into the relationship between feeding patterns and the fine‐scale variation in leaf chemistry occurring within the host plant. The weevils’ feeding patterns were the simplest in temporal structure of any reported to date for an insect herbivore. Weevils spent an average of only 3% of their time feeding during the 10‐h observation periods. Meals lasted an average of 2.8 min and occurred at a mean intermeal interval of 84 min. The feeding patterns gave the appearance of a short‐term rhythm underlying the onset of feeding (as has been found in locusts and caterpillars), although there were insufficient meals taken by individuals over the 10‐h period to test this suggestion. Meals were notable in apparently lacking intrameal pauses and also commencing without preliminary sampling behaviours, such as palpating or biting. Whether the combination of short, infrequent meals, ingested without pauses and not preceded by sampling behaviour, represents an adaptation reducing apparency to natural enemies, or else simply reflects low nutritional needs, is discussed. Correlations between meal durations and following and preceding intermeal intervals suggested that variation in intermeal intervals stemmed largely from variation in meal duration, not vice versa, with variation in meal duration resulting from an external influence such as leaf nutritional and/or allelo‐chemistry. The latter suggestion is currently being tested.
Relationship between sex pheromone elicited behaviour and response of single olfactory receptor neurones in a wind tunnel
Authors: Valeur Peter G. , Hansson Bill S. , Markebo Kristin , Löfstedt Christer 
Published: March 2003

SummaryResponses from pheromone‐specific receptor neurones in male Agrotis segetum (Denis & Schiffermüller) (Lepidoptera: Noctuidae) were recorded in a laboratory wind tunnel. Stimuli were: (1) rubber septum dispensers loaded with single components or a four‐component pheromone blend, (2) excised glands from female A. segetum, (3) constrained A. segetum females with extruded glands. Dose–response curves for three neurone‐types with different specificity were established. The neurones were specifically tuned to respond to either one of the two pheromone components (Z)‐5‐decenyl acetate and (Z)‐7‐dodecenyl acetate, or to the behavioural antagonist (Z)‐5‐decenol. In parallel, a behavioural dose–response curve with males flying upwind to a four‐component pheromone blend was established. There was a clear correlation between behavioural arrestment of upwind flight and maximum spiking activity in Z5–10:OAc‐specific neurones.The pheromone release rates of individual females and synthetic dispensers were compared. A load of 50–200 ng of Z5–10:OAc on a rubber septum elicited approximately the same neural response as one female gland.
The structure and function of songs emitted by southern green stink bugs from Brazil, Florida, Italy and Slovenia
Authors: Cˇokl Andrej , Virant‐Doberlet Meta , Stritih Natasˇa 
Published: March 2003

Summary Nezara viridula (L.) (Pentatomidae: Heteroptera) from Brazil, Florida, Italy and Slovenia, communicate by vibratory songs associated with long‐range calling and close‐range courting, rivalry and repelling. Each song is composed of spectrally and temporally different units. Spectrally different pulses of duration less than 300 ms are present in the male calling song. The female calling song is characterized by pulse trains composed of pulses shorter than 150 ms and pulse trains composed of a longer (> 700 ms) and shorter (< 250 ms) pulse. Shorter and longer pulses have different spectral characteristics. The male and female courtship songs are characterized by fusion of shorter (< 150 ms) pulses into a pulse train usually followed by a shorter (< 200 ms) postpulse in the case of the male courtship song. The female repelling song is a several seconds long vibration of irregular temporal structure. The short (< 400 ms) male rival song pulses are frequency modulated. The dominant frequency peaks of the songs investigated lie between 70 and 130 Hz. The dominant frequency and the microstructure of song spectra show no population specificity. The average duration varies more in calling than in courtship songs. The repetition time varies extensively in songs of different populations. Normal communication followed by copulation was observed between mates from Slovenia and Brazil and between mates from Florida and Italy. The potential role of different temporal and spectral parameters for species recognition and mate location is discussed in view of the expected distortion of the characteristic signal structure during transmission through plants.
Temperature and the hygropreference of the Arctic CollembolanOnychiurus arcticusand miteLauroppia translamellata
Authors: Hayward S. A. L. , Worland M. R. , Bale J. S. , Convey P. 
Published: March 2003

SummaryThe hygropreference of adultOnychiurus arcticus(Tullberg) was investigated over 2 h at 0, 10 and 20°C, along humidity gradients (12–98% RH) established using different salt solutions. At all temperaturesO. arcticuspreferred the highest humidity (98% RH). At 0 and 20°C, saturated conditions were preferred to 98% RH. The hygropreference of the miteLauroppia translamellata(Willmann) was also assessed at 20°C, and no clear RH preference was observed. This species survived the loss of 24.9 ± 2.1% of its initial water content when held for 24 h at 20°C and 12% RH. A range of assays designed to eliminate the influence of thigmotactic behaviour and population clumping permit exclusion of these factors as being responsible for the observed results. The mean initial water content ofO. arcticussamples (71.7 ± 10.9, 73.4 ± 4.0 and 73.8 ± 23.5% at 0, 10 and 20°C, respectively) did not differ significantly between temperatures, indicating that the results were not influenced by differences in initial hydrated state. The percentage water loss of individuals within the gradient increased with temperature, and differed significantly between regimes. The ecological significance of the observed humidity preferences are discussed.
Identification of feeding attractants in oak sap for adults of two nymphalid butterflies, Kaniska canace and Vanessa indica
Authors: Ômura Hisashi , Honda Keiichi , Hayashi Nanao 
Published: March 2003

AbstractThe active compounds of oak‐sap odour in attracting adults of two butterflies, Kaniska canace (L.) and Vanessa indica (Herbst) (Lepidoptera: Nymphalidae), were identified by chemical analyses, electroantennogram (EAG) and two behavioural assays: proboscis extension reflex (PER) and attraction to artificial tree models. Fourteen compounds were identified from two sap samples collected in 1997 and 1998, of which the major volatiles were ethanol and acetic acid (≈ 900 p.p.m. and 500 p.p.m. in sap, respectively). However, the chemical composition of the minor volatiles varied considerably between the two samples. Among 13 chemicals tested, V. indica showed strong PER to five aliphatic acids (acetic, propionic, butyric, isobutyric and isovaleric), 2‐methylpropan‐1‐ol and 3‐hydroxybutan‐2‐one, whereas the PER‐active compounds for K. canace were these seven compounds and also ethanol, 3‐methylbutan‐1‐ol and 1‐hydroxypropan‐2‐one. In two‐choice behavioural bioassays, the model scented with a sap‐odour mimic, which was an aqueous mixture of the PER‐active compounds, was more attractive to the two butterflies than an unscented control. These results demonstrated that the sap odour stimulates foraging behaviour of the butterfly. Although EAG responses of both butterflies to 3‐methylbutan‐1‐ol and that of V. indica to 2‐methylpropan‐1‐ol were positively dose‐dependent, responses to other compounds were not strong and not dose‐dependent at 1–100 μg doses. These EAG responsiveness suggests that the olfactory receptors for these compounds might be few in the antenna and that the butterflies have enough olfactory sensitivity to the dose of 1 μg.
Reproductive allocation by the blow fly Lucilia sericata in response to protein limitation
Authors: Wall R. , Wearmouth V. J. , Smith K. E. 
Published: March 2003

Abstract.Adult females of the anautogenous blow fly Lucilia sericata (Meigen) (Diptera: Calliphoridae) were fed standardized meals of liquidized liver, in quantities shown to range around the minimum required to initiate yolk deposition. Females from each feeding regime were dissected at daily intervals between 4 and 11 days of age; the number and stage of development of all oöcytes were recorded. Once an initial threshold quantity of protein was ingested, yolk deposition was initiated in all available oöcytes. Subsequently, one of two distinct developmental pathways was followed: arrested development in all oöcytes at an early stage of yolk deposition, or more extensive yolk deposition followed by progressive oösorbtion and the maturation of small batches of eggs. The proportion of females showing oösorbtion relative to arrested follicular development increased with increasing protein meal size, suggesting that the difference in response may be triggered by a second protein threshold, either side of which the arrested development or oösorbtion pathways are followed. The behaviour observed may reflect strategies to maximize reproductive output in this short‐lived, resource‐limited insect species. Flies that display arrested development may have sufficient protein to mature few if any complete eggs, but may subsequently be able to mature a full egg‐batch if they obtain further protein meals; this possibility is offset by the risk of death before finding such a meal. Flies that show oöcyte development and oösorbtion produce smaller egg batches more quickly and hence have a higher probability of achieving at least some reproductive output. By initiating yolk deposition in all oöcytes, female L. sericata retain the potential to adopt either developmental pathway, depending on subsequent protein intake.