bluuebunny/crossref_metadata_2025_split huggingface dataset:
Risks of hypertensive disorders in the second pregnancy
Authors: Zhang Jun , Troendle James F. , Levine Richard J. 
Published: March 2003

SummaryThis study examined the incidence of and risk factors for recurrent and newly developed hypertensive disorders in the second pregnancy. We analysed data on 1641 women who had both the first and second pregnancies in the Collaborative Perinatal Project, a large prospective cohort study at 12 hospitals in the US. Nineteen per cent [95% CI 14%, 24%] of women who had gestational hypertension in the first pregnancy, 32% [95% CI 17%, 48%] of those with pre‐eclampsia and 46% [95% CI 32%, 60%] of patients with gestational hypertension or pre‐eclampsia superimposed on chronic hypertension, had recurrent hypertensive disorders in the second pregnancy. Risk factors for recurrence included history of chronic hypertension and thromboembolism, early onset of hypertension in the first pregnancy or persistent hypertension after 5 weeks postpartum and high baseline blood pressure in the second pregnancy. Women with a normotensive first pregnancy but a severe small‐for‐gestational‐age birth had twice the risk of developing hypertension in the second pregnancy (RR = 2.1, 95% CI, 1.1, 4.0). In summary, hypertensive disorders have a 20–50% recurrence rate in the second pregnancy. The earlier the onset of hypertension in the first pregnancy, the higher the overall recurrence rate. Intrauterine growth restriction of the first birth is an independent risk factor for hypertension in the second pregnancy.
Cerebral palsy in Northern Ireland: 1981–93
Authors: Parkes Jackie , Dolk Helen , Hill Nan , Pattenden Sam 
Published: March 2003

SummaryThis paper describes the method of compilation of the Northern Ireland Cerebral Palsy Register (NICPR) and outlines the epidemiology of cerebral palsy (CP) in Northern Ireland in 1981–93 based on an analysis of 784 cases. Multiple and overlapping sources of notification were used to compile the NICPR. Each case was followed up with a standardised assessment completed at age 5 years and validated by a paediatrician. Over 70% of cases were multiply notified, and paediatricians were the most important source of notification. Cases of CP most likely to be under‐ascertained included those very mildly affected, cases who died before the register began (death certificates were searched but found to be unreliable) and cases who moved out of the area before their diagnosis was confirmed. The prevalence of CP for the birth period 1981–93 was 2.24 per 1000 livebirths [95% CI 2.08, 2.40]. There were no statistically significant temporal or geographic variations in the rate of CP. Almost half the cases of CP were of low birthweight (<2500 g), and this proportion increased during 1987–89, but decreased (P< 0.01) more recently (1990–93). The proportion of cases weighing <1000 g trebled from 3% in 1981–83 to 10% in 1990–93 (P< 0.01). The most common CP subtype was bilateral spastic cerebral palsy (55%). Just over a quarter (29%) of cases were unable to walk (with/without aids), and one‐fifth (22%) had no useful hand/arm function. Almost half (49%) the cases had at least one other impairment (intellectual, sensory impairment or active seizures) in association with their CP. Prevalence rates and the pattern of disability in populations of people with CP can only be evaluated on the basis of the methods of case definition and ascertainment. We have demonstrated the methods necessary to ensure valid, standard and detailed information on CP for the purposes of surveillance, service planning and research.
Measuring functional developmental delay in infants and young children: prevalence rates from the NHIS‐D
Authors: Simpson Gloria A. , Colpe Lisa , Greenspan Stanley 
Published: March 2003

SummaryIn order to measure the prevalence of developmental delay among US infants and children, two types of questions were asked of parents in the 1994–95 National Health Interview Survey on Disability (NHIS‐D). To measure functional delay (FD), questions from the Functional Developmental Growth Chart (FDQ), which measures specific age‐appropriate tasks, were used. General delay (GD) was defined using the general type of questions about developmental delay that had been used in previous surveys. Using a nationally representative sample of 15 291 infants and children aged 4–59 months from the NHIS‐D, analyses revealed that, according to these questions, ≈ 3.3% had FD and 3.4% of the children had GD. However, only one‐third of the children were identified by both sets of questions. Thus, two‐thirds of the children identified as having FD were not recognised by their parents as having a delay. Conversely, many parents responded to the GD questions indicating that their child had a delay, but failed to indicate that their child had a functional problem. In addition, only 17% of the children with FD and 31% of those with GD were receiving special services. Multivariable logistic regression analyses found that children with both FD and GD were more likely to be male and to be living in families with incomes below 200% of the poverty level. The findings suggest that the general types of developmental delay questions used in national surveys may not identify children with functional delays. As parents failed to identify these children, it is possible that many of these children may be slipping through paediatric surveillance. Further research to evaluate the use of these measures in population surveys is recommended.
Antenatal mycoplasma infection, the fetal inflammatory response and cerebral white matter damage in very‐low‐birthweight infants
Authors: Dammann Olaf , Allred Elizabeth N. , Genest David R. , Kundsin Ruth B. , Leviton Alan 
Published: March 2003

SummaryWe address the question as to whether Ureaplasma urealyticum or Mycoplasma hominis, cultured from the placenta of very‐low‐birthweight (VLBW) infants, are associated with an increased risk of (a) fetal vasculitis and (b) ultrasonographic cerebral white matter echolucency. The sample consisted of 464 VLBW infants for whom (i) the surface of the chorion was cultured for U. urealyticum and M. hominis; (ii) the placenta was examined histologically; and (iii) a cranial ultrasound scan was obtained close to days 1, 7 or 21. Infants with echolucency were compared with controls in univariable and stratified analyses and in multivariable logistic regressions.Fifty‐three per cent of placentas from infants with fetal vasculitis harboured U. urealyticum compared with 18% of controls (P ≤ 0.001). M. hominis was present in 14% of cases of fetal vasculitis and in 2% of controls (P ≤ 0.001). Among cases of echolucency, 22% had U. urealyticum compared with 30% of controls (P = 0.33), whereas 17% of these cases and 5% of controls had M. hominis (P = 0.08). Our findings support the hypothesis that U. urealyticum in the placenta of VLBW infants contributes to the fetal inflammatory response without contributing to white matter damage. Our finding that M. hominis in the placenta was associated with a not quite significant threefold risk increase for echolucency deserves further investigation.
Effect of constant light on male sterility in the cotton leafworm Spodoptera littoralis
Authors: Bębas P. , Cymborowski B. 
Published: March 2003

SummaryFemales of the cotton leafworm (Spodoptera littoralis) reared in long day conditions (LD 16:8 h) and mated to males kept throughout the whole period of development in continuous light (LL) oviposit very small numbers of mostly sterile eggs. It was found that in control males reared from the first larval instar in long day conditions there was a large accumulation of euperene sperm bundles in their testes on day 1 after imaginal moult. On day 10 of adult life the number of the sperm bundles was very small. In males kept from the first instar in continuous light there was also high number of sperm bundles on day 1 after imaginal moult but it did not decrease significantly on day 10 as was observed in controls. Transfer of different developmental stages of S. littoralis from long day conditions to continuous light resulted in a big difference in the density of eupyrene sperm bundles in their testes. In control insects reared through the whole of their development in long day conditions there was a significant decrease in the density of eupyrene sperm bundles on day 10 of adult life. By contrast, in males in continuous light, regardless of their developmental stage when transferred, there was either no change in density of sperm bundles in day 10 adults or there was a significant increase in comparison with day 1 adults. The highest density of eupyrene sperm bundles was observed in day 10 adults when they were transferred to continuous light shortly before moulting to the last instar (as day 4 larvae in the last stadium or day 1 pupae). Generally, the density of eupyrene sperm bundles on day 10 of adult development was about 2–2.5 times higher in males in continuous light then those under long day conditions. The results presented here indicate that the last larval instar and the pupa are the stages most sensitive to constant light treatment, which greatly reduces the amount of eupyrene sperm bundles released from the testes.
The major carotenoid pigments of the grain aphid, Sitobion avenae (F.) (Hemiptera: Aphididae)
Authors: Jenkins R. L. , Loxdale H. D. , Brookes C. P. , Dixon A. F. G. 
Published: March 2003

SummaryThe economically important grain aphid, Sitobion avenae (F.) shows colour polymorphism, with brown and green forms predominating. Colour is determined both genetically and in response to environmental factors, including nutrition. The biological significance of the colour polymorphism is unknown, although seasonal changes occur in the frequency of colour morphs in the field, whilst the brown morph may have adaptive significance in terms of hymenopterous endoparasitism. The ground colour of aphids is produced by haemolymph pigments, aphins (glucosides) and carotenoids. The latter may be under the synthetic control of intracellular endosymbiotic bacteria. In this study, the major carotenoid pigments of a brown and a green clone of S. avenae were examined using thin layer chromatography (TLC) and high‐performance liquid chromatography (HPLC), and their absorbance spectra recorded. Using TLC, the brown clone produced five bands of different Rf, ranging from yellow, to orange‐pink to pink in colour. In contrast, the green clone gave only a single yellow band of higher Rf than any of the bands of brown aphids. Following separation of carotenoids by HPLC, brown aphids gave seven peaks and green aphids five. Comparison of absorbance maxima with known published values for carotenoids provides strong evidence for the identification of four of the carotenoid pigments from brown aphids (RB‐4, 3,4‐didehydrolycopene; RB‐5, torulene; RB‐6; lycopene; RB‐7, γ‐carotene) and one from green aphids (RG‐2, α‐carotene). The other carotenoids remain unidentified. The biosynthesis and possible biological relevance of the various pigments of S. avenae are briefly discussed.
Spatial and temporal structures of pheromone plumes in fields and forests
Authors: Murlis John , Willis Mark A. , Cardé Ring T. 
Published: March 2003

SummaryWind‐borne odour stimuli from a small point‐source of pheromone are intermittent owing to the effects of atmospheric turbulence on the odour plume. The work reported here measures the characteristics of the intermittent stimulus in open fields and forests during typical daytime atmospheric conditions. To model the pheromone plume, negatively charged atmospheric ions were used as a tracer. They were released from an ion generator, and ion detectors measured the fluctuating flux of ions at positions up to 20 m downwind in the open field case and 10 m in the forest. In both the open field and in the forest, ion signals were highly intermittent, with a signal present only 20% of the time. Ion signals recorded in the forest consisted of bursts with gaps between them of at least three‐fold greater duration than those from the open field. In both environments, bursts generally each comprised a series of ‘spikes’, on average three in the field and seven in the forest. To validate the use of ionized air plumes as models of pheromone plumes, the antennae of male Lymantria dispar (gypsy moth) were used as detectors to quantify the plume of synthetic (+)‐disparlure emanating from a 2000 ng point source placed ≈ 10 cm from the ion source. A comparison of ion signals and EAGs (electronantennograms) suggests that the antennae respond to the main spikes within a burst, but no consistent relationship between the strength of the spikes and the magnitude of the EAG response was found. The average strengths of bursts in the ion detector signal decreased systematically as the distance from the ion generator to the ion detector increased. A similar trend, however, was not detected in the EAG response.
Temperature related effects on embryonic development of the Mediterranean locust, Dociostaurus maroccanus
Authors: Quesada‐Moraga E. , Santiago‐Álvarez C. 
Published: March 2003

SummaryLaboratory studies were conducted to assess the effect of temperature on the development of the eggs of Dociostaurus maroccanus (Thunberg) (Orthoptera, Acrididae) during anatrepsis (stages I–XIV) and during catatrepsis (stages XV–XX). The developmental rates of anatrepsis were studied at five constant temperatures ranging from 10 to 30°C. Egg development occurred over the entire range but at 10°C the embryos were unable to complete anatrepsis. The relationship between temperature and developmental times for completing anatrepsis was analysed by the non‐linear Logan type III model. The optimal temperature estimated for the development of eggs during anatrepsis was 24.7°C; the lower and upper thermal thresholds were 9°C and 31°C, respectively. Once the embryos completed anatrepsis, only those incubated at 15°C continued morphogenesis beyond stage XIV (diapause stage) without a low‐temperature exposure period. The developmental rate of catatrepsis was studied at four constant temperatures ranging from 15°C to 30°C after exposure to low‐temperature, 10°C, for 30, 60 or 90 days. For catatrepsis, temperature and developmental time were linearly and inversely related. Linear regression was used to estimate the lower developmental threshold and the degree days requirements for catatrepsis. Both decreased with longer exposure to the low temperature; the former from 13.8°C to 10.5°C and the latter from 212.8 to 171.5 degree days, following 30 and 90 days at 10°C, respectively. Our results improve the ability of decision support systems for Mediterranean locust pest management by providing better forecasts to land managers and pest advisors.
A microdialysis study of allatostatin degradation in Blattella germanica (L.) (Dictyoptera, Blattellidae)
Authors: Peralta Enrique , Vilaplana Lluïsa , Pascual Nuria , Carreño Cristina , Piulachs Maria‐Dolors , Andreu David , Bellés Xavier 
Published: March 2003

SummaryAllatostatins with a typical C‐terminal sequence YXFGL‐NH2 are insect neuropeptides with inhibitory properties upon Juvenile Hormone production in the corpora allata, vitellogenin release by the fat body, and gut and dorsal vessel motility. All these biological effects are rapidly reversible, suggesting the occurrence of effective mechanisms for inactivation of the peptides. We have studied the degradation of DRLYSFGL‐NH2 (BLAST‐2), one of the allatostatins of Blattella germanica, in the internal milieu of adult females of this cockroach. The experimental approach combined the use of the radioiodinated derivative [125I‐Tyr4]BLAST‐2, microdialysis techniques and HPLC analysis with a radioisotope detector. Under these experimental conditions, the half‐life of BLAST‐2 in the internal milieu of the adult female of B. germanica was between 3 and 6 min. Such a short half‐life explains the high doses of allatostatins required to obtain the expected biological effects when tested in vivo, and suggests that circulating allatostatins are subject to rapid rates of synthesis and degradation in order to be operative physiologically.
A model of isoprene emission based on energetic requirements for isoprene synthesis and leaf photosynthetic properties for Liquidambar and Quercus
Authors: Niinemets Ü. , Tenhunen J. D. , Harley P. C. , Steinbrecher R. 
Published: March 2003

ABSTRACTWe present a physiological model of isoprene (2‐methyl‐1,3‐butadiene) emission which considers the cost for isoprene synthesis, and the production of reductive equivalents in reactions of photosynthetic electron transport for Liquidambar styraciflua L. and for North American and European deciduous temperate Quercus species. In the model, we differentiate between leaf morphology (leaf dry mass per area, MA, g m−2) altering the content of enzymes of isoprene synthesis pathway per unit leaf area, and biochemical potentials of average leaf cells determining their capacity for isoprene emission. Isoprene emission rate per unit leaf area (μmol m−2 s−1) is calculated as the product of MA, the fraction of total electron flow used for isoprene synthesis (ɛ, mol mol−1), the rate of photosynthetic electron transport (J) per unit leaf dry mass (Jm, μmol g−1 s−1), and the reciprocal of the electron cost of isoprene synthesis [mol isoprene (mol electrons−1)]. The initial estimate of electron cost of isoprene synthesis is calculated according to the 1‐deoxy‐
D‐xylulose‐5‐phosphate pathway recently discovered in the chloroplasts, and is further modified to account for extra electron requirements because of photorespiration. The rate of photosynthetic electron transport is calculated by a process‐based leaf photosynthesis model. A satisfactory fit to the light‐dependence of isoprene emission is obtained using the light response curve of J, and a single value of ɛ, that is dependent on the isoprene synthase activity in the leaves. Temperature dependence of isoprene emission is obtained by combining the temperature response curves of photosynthetic electron transport, the shape of which is related to long‐term temperature during leaf growth and development, and the specific activity of isoprene synthase, which is considered as essentially constant for all plants. The results of simulations demonstrate that the variety of temperature responses of isoprene emission observed within and among the species in previous studies may be explained by different optimum temperatures of J and/or limited maximum fraction of electrons used for isoprene synthesis. The model provides good fits to diurnal courses of field measurements of isoprene emission, and is also able to describe the changes in isoprene emission under stress conditions, for example, the decline in isoprene emission in water‐stressed leaves.
Growth in elevated CO2 protects photosynthesis against high‐temperature damage
Authors: Taub Daniel R. , Seemann Jeffrey R. , Coleman James S. 
Published: March 2003

ABSTRACTWe present evidence that plant growth at elevated atmospheric CO2 increases the high‐temperature tolerance of photosynthesis in a wide variety of plant species under both greenhouse and field conditions. We grew plants at ambient CO2 (~ 360 μmol mol−1) and elevated CO2 (550–1000 μmol mol−1) in three separate growth facilities, including the Nevada Desert Free‐Air Carbon Dioxide Enrichment (FACE) facility. Excised leaves from both the ambient and elevated CO2 treatments were exposed to temperatures ranging from 28 to 48 °C. In more than half the species examined (4 of 7, 3 of 5, and 3 of 5 species in the three facilities), leaves from elevated CO2‐grown plants maintained PSII efficiency (Fv/Fm) to significantly higher temperatures than ambient‐grown leaves. This enhanced PSII thermotolerance was found in both woody and herbaceous species and in both monocots and dicots. Detailed experiments conducted with Cucumis sativus showed that the greater Fv/Fm in elevated versus ambient CO2‐grown leaves following heat stress was due to both a higher Fm and a lower Fo, and that Fv/Fm differences between elevated and ambient CO2‐grown leaves persisted for at least 20 h following heat shock. Cucumis sativus leaves from elevated CO2‐grown plants had a critical temperature for the rapid rise in Fo that averaged 2·9 °C higher than leaves from ambient CO2‐grown plants, and maintained a higher maximal rate of net CO2 assimilation following heat shock. Given that photosynthesis is considered to be the physiological process most sensitive to high‐temperature damage and that rising atmospheric CO2 content will drive temperature increases in many already stressful environments, this CO2‐induced increase in plant high‐temperature tolerance may have a substantial impact on both the productivity and distribution of many plant species in the 21st century.
Ground monitoring the light–shadow windows of a tree canopy to yield canopy light interception and morphological traits
Authors: Giuliani Rita , Magnanini Eugenio , Fragassa Cristiano , Nerozzi Fabrizio 
Published: March 2003

ABSTRACTMonitoring the light–shadow windows of a tree via a grid system on the ground was performed on sunny summer days at high spatial resolution using a custom‐built, inexpensive scanner. The measurements were taken with two goals: (1) to quickly and remotely quantify the overall, short‐wave solar radiation (300–1100 nm) intercepted by the tree canopy, and (2) to yield such crown geometric traits as shape, size and the number of theoretical canopy leaf layers (leaf layer index, LLI) in relation to the section orthogonal to sunbeam direction (sun window). The ground readings at each measurement over the day were used to project a digitized shadow image. Image processing was applied and the intercepted radiation was calculated as the difference from the corresponding incoming radiation above the canopy. Tree‐crown size and shape were profiled via computer imaging by analysing the different shadow images acquired at the various solar positions during the day. It is notable that these combined images yielded the crown features without having to parameterize such canopy characteristics as foliage extension and spatial distribution.
The growth response of C4 plants to rising atmospheric CO2 partial pressure: a reassessment
Authors: Ghannoum O. , Caemmerer S. Von , Ziska L. H. , Conroy J. P. 
Published: March 2003

ABSTRACTDespite mounting evidence showing that C4 plants can accumulate more biomass at elevated CO2 partial pressure (p(CO2)), the underlying mechanisms of this response are still largely unclear. In this paper, we review the current state of knowledge regarding the response of C4 plants to elevated p(CO2) and discuss the likely mechanisms. We identify two main routes through which elevated p(CO2) can stimulate the growth of both well‐watered and water‐stressed C4 plants. First, through enhanced leaf CO2 assimilation rates due to increased intercellular p(CO2). Second, through reduced stomatal conductance and subsequently leaf transpiration rates. Reduced transpiration rates can stimulate leaf CO2 assimilation and growth rates by conserving soil water, improving shoot water relations and increasing leaf temperature. We argue that bundle sheath leakiness, direct CO2 fixation in the bundle sheath or the presence of C3‐like photosynthesis in young C4 leaves are unlikely explanations for the high CO2‐responsiveness of C4 photosynthesis. The interactions between elevated p(CO2), leaf temperature and shoot water relations on the growth and photosynthesis of C4 plants are identified as key areas needing urgent research.