bluuebunny/crossref_metadata_2025_split huggingface dataset:
Implications of cleaning gestational age data
Authors: Parker Jennifer D. , Schoendorf Kenneth C. 
Published: March 2003

SummaryGestational age is an important birth characteristic examined in epidemiological studies. Though there are well‐documented problems with the reporting of gestational age on birth certificates, schemes for addressing this issue have not been systematically evaluated. With singleton births from the 1995–97 US linked birth/infant death files, we compared a handful of perinatal outcome estimates derived from the resulting analytical files using two published methods often used to manage inconsistent gestational age data. The first method (Alexander et al., 1996), provides cut‐points for implausible birthweight–gestational age combinations and excludes infants with birthweights outside a plausible range. The second (Zhang and Bowes, 1995), provides different cut‐points for implausible birthweight–gestational age combinations and then substitutes the clinical gestational age estimate for the original value, if available, reducing the number of births at the affected gestational age, but excluding fewer births from the resulting analytical files. The Alexander method excluded 0.4% of our study population and the Zhang method reassigned and excluded 1.0% and 0.2%, respectively; however, over 20% of birth records with gestational age 28–30 weeks were modified by either method. Using either method, more high‐risk than low‐risk and more black than white births were excluded. These differential exclusions affected corresponding perinatal outcome estimates and relative risks between maternal risk groups for preterm delivery, gestation‐specific infant mortality and birthweight; overall infant mortality rates were not affected. Systematic comparisons between results of different studies will need to consider the data modifications used, the populations affected, and the outcomes assessed when drawing conclusions.
Epidemiological features of uterine rupture in West Africa (MOMA Study)
Authors: Joud Dahada Ould El , Prual Alain , Vangeenderhuysen Charles , Bouvier‐Colle Marie‐Hélène , Group The MOMA 
Published: March 2003

SummaryThe aim of the study was (1) to assess the incidence of uterine rupture in West Africa; (2) to identify its risk factors there; (3) to assess their predictiveness. The study (MOMA study) was prospective and population based. Data on a large cohort of pregnant women were collected. Univariable and multivariable analysis was used including stepwise logistic regression. We identified 25 cases of clinically symptomatic uterine rupture in a population of 20 326 pregnant women giving an incidence rate of 1.2 uterine ruptures per 1000 deliveries. Five variables were significantly associated with uterine rupture (in both the univariable and multivariable analyses): uterine scars, malpresentation, limping, cephalopelvic disproportion and high parity (≥7). In conclusion, the incidence of uterine rupture is high in West Africa, even in large cities where essential obstetric care is available and despite the low prevalence of uterine scars. A uterine scar multiplies the risk of uterine rupture by 11. Uterine rupture cannot be predicted from currently known risk factors, including uterine scars. The high case fatality rate (33.3%) and the associated perinatal mortality (52%) bear witness to the absence or inadequacy of health facilities in providing essential obstetric care and to the poor quality of maternal health care, even in major cities.
Deprivation and stillbirth risk in rural and urban areas
Authors: Dickinson Heather O. , Hutton Jane L. , Greaves Lynda H. , Dummer Trevor J. B. , Parker Louise 
Published: March 2003

SummaryThe objective of the study was to investigate whether stillbirth risk was higher, and the effect of deprivation on inequality in stillbirth risk more marked, in rural than in urban areas. We carried out a cohort study of all 280 757 singleton births to mothers domiciled in Cumbria, north‐west England, 1950–92. After allowing for individual social class and community deprivation, the risk of stillbirth was lower outside urban centres both during 1950–65 (OR = 0.91, 95% CI 0.84, 1.00) and during 1966–92 (OR = 0.82, 95% CI 0.73, 0.92). In earlier years, unsupported mothers in rural areas and mothers living in remote areas were particularly at risk. Urban/rural differences in risk were not explained by individual social class, community deprivation or overcrowding and have persisted over a 40‐year time period.
A district‐based analysis of stillbirth and infant mortality rates in Italy: 1989–93
Authors: Lauria Laura , De Stavola Bianca L. 
Published: March 2003

SummaryDespite a substantial decline in stillbirth and infant mortality rates in Italy during the last century, there are still large differences between the north and south of the country. This paper analyses the geographical distribution of these rates in the period 1989–93 in terms of biological and social indicators with the aim of identifying possible sources for these differentials. Numbers of stillbirths, infant deaths and deliveries were available in an aggregate form by categories of biological and social factors for each of the 95 Italian administrative districts (‘province’) operative at the time. Substantial differences in stillbirth (SB) and infant mortality (IM) rates were found across geographical areas, with the lower rates found in the richer and more industrialised north and the higher ones in the more deprived south. Negative binomial regression models were used to study the geographical variations in these rates in terms of biological and social factors. The latter showed strong and significant effects on both SB and IM rates, even after controlling for biological factors. The effects of the biological factors, birthweight and maternal parity in particular, however, were found to differ across geographical areas. Further studies to investigate whether these results may be explained by differentials in health care should be considered.
Effects of irradiation on Plasmodium falciparum sporozoite hepatic development: implications for the design of pre‐erythrocytic malaria vaccines
Authors: Silvie O. , Semblat J. P. , Franetich J. F. , Hannoun L. , Eling W. , Mazier D. 
Published: March 2003

SummaryImmunization with irradiation‐attenuated Plasmodium sporozoites confer protection against live sporozoite challenge. Protection relies primarily on cytotoxic lymphocyte activity against infected hepatocytes, and is suppressed when sporozoites are over‐irradiated. Here, we demonstrate that over‐irradiated (25–30 krad) Plasmodium falciparum sporozoites invade human hepatocytes and transform into uninucleate liver‐trophozoites with the same efficiency as non‐irradiated and irradiation‐attenuated (12–15 krad) sporozoites. Since hepatocytes infected with over‐irradiated non‐protective sporozoites are likely to express sporozoite‐derived peptide/major histocompatibility complex class I molecules on their surface, our results strongly suggest that sporozoite proteins are not the main immunogens involved in protection, and thus may not per se constitute proper malaria vaccine candidates.
Three‐dimensional analysis of aphid landing behaviour in the laboratory and field
Authors: Storer J. Robert , Young Stephen , Hardie JiM. 
Published: March 2003

SummaryThe final second of the landing approach of black bean aphids,Aphis fabae,was analysed in three dimensions using video techniques. A yellow landing platform was placed upwind or downwind from aphids aggregating under a ceiling light in a laboratory wind tunnel with 10, 20, 30, 40 or 50 cm s–1wind speeds, and up‐tunnel or down‐tunnel in still air. As individual aphids flew to the platform, body orientation (assessed by direct observation) was predominantly into‐wind whether the initial flight direction to the landing platform was upwind or downwind. A greater proportion showed into‐wind body orientation as wind speed increased. Flight track parameters which differed significantly between wind speeds were the track length, linear start to finish distance, linearity index, horizontal ground speed, speed vertical to the ground, vertical turning rate, and horizontal turning rate. The position of the landing platform was important for track length, linear start to finish distance, horizontal ground speed, three‐dimensional turning rate, horizontal turning rate, vertical turning rate, and sinuosity. As wind speed increased above 30 cm s–1the ground speed became more consistent and indicated considerable variation in air speed to adjust for ground speed. For the majority of aphids there was a strong preference (88%) for into‐wind landings with initial upwind directed flight, while for downwind flights a significant number (55%) of insects reversed initial flight direction and landed into‐wind. Field recorded landings showed that 66% of aphids landed into‐wind and there was a mean bearing to the wind of 71 ± 42°, a similar finding to wind‐tunnel studies.
Circadian locomotor rhythm masked by the female reproduction cycle in cockroaches
Authors: Tsai C.H.I.‐W.E.I. , Lee H.O.W.‐J.I.N.G. 
Published: March 2003

Summary Blattella bisignata (Brunner) and B. germanica (L.) are oviparous cockroaches with cyclic reproductive behaviour, but in B. germanica only males show circadian rhythmicity of locomotion at 28°C and DD (constant darkness). In B. bisignata, males and virgin females cockroaches entrained by light–dark cycles show free‐running rhythmicity in DD, and most activities occur during the subjective night. Daily locomotor activities of virgin females show cyclic changes that coincided with ovarian development. Virgin females also exhibit calling behaviour during the subjective night, and this shows a free‐running rhythm. Male mate‐finding locomotion and female calling behaviour are under circadian control, so the timing for both behaviours is synchronized. However, most mated females do not show a locomotor free‐running rhythm under DD conditions. Our results indicate that only mated females could not express a circadian locomotor rhythm. Pregnancy reduces a female’s locomotory intensity and masks the expression of a circadian locomotor rhythm. We attribute the differences in circadian locomotory rhythms between these two species to their living environments and mate‐finding strategies.
Orientation of specialist and generalist fungivorous ciid beetles to host and non‐host odours
Authors: Guevara Roger , Rayner Alan D. M. , Reynolds Stuart E. 
Published: March 2003

AbstractMost ciids (Ciidae) are strict fungivores specialized on fruit bodies of wood‐rotting fungi. The Ciidae includes both specialist and generalist species. Recent evidence suggests that ciids locate and discriminate their potential hosts based mainly on fungal odours. In this study, we investigated the field distribution of ciids in a local woodland near Bath, U.K. We also evaluated experimentally the behavioural responses of ciids to host and non‐host fungi in an olfactometer, and explored potential differences in putative aroma compounds in host fungi.Our field data showed that Octotemnus glabriculus, Cis boleti and Cis nitidus have preference for one host species, whereas C. bilamellatus has no preference. The experimental evidence was in accordance with the field observations. The specialists O. glabriculus, C. boleti and C. nitidus were specifically attracted to odour compounds of their preferred host fungi: Coriolus versicolor for the first two beetles and Ganoderma adspersum for the latter one. By contrast, the generalist C. bilamellatus was attracted to odours from C. versicolor, G. adspersum and Piptoporus betulinus.The evidence from this and other published studies suggest that ciids depend mainly on fruit body odours for location and discrimination of their host fungi. In accordance with this, we observed diffierential behavioural responses of ciids to aroma compounds of host and non‐host species.
Sexual dimorphism in the pyrgomorphid grasshopper Phymateus morbillosus: from wing morphometry and flight behaviour to flight physiology and endocrinology
Authors: Gäde Gerd 
Published: March 2003

Abstract In the field, adult males of the grasshopper Phymateus morbillosus are able to fly for up to 1 min and cover up to c. 100 m, whereas females, although fully winged, are apparently unable to get airborne. Morphometric data indicate that the males are lighter, have longer wings, a higher ratio of flight muscles to body mass, and a lower wing load value than females. It was investigated whether this inability of females to fly is related to fuel storage, flight muscle enzymatic design and/or the presence and quantitative capacity of the endocrine system to mobilize fuels. In both sexes, readily available potential energy substrates are present in the haemolymph in similar concentrations, and the amount of glycogen in flight muscles and fat bodies does not differ significantly between males and females. Mass‐specific activities of the enzymes GAPDH (glycolysis), HOAD (fatty acid oxidation) and MDH (citric acid cycle) in flight muscles are significantly lower in females compared with males, and mitochondria are less abundant in the flight muscles of females. There is no significant difference between the ability of the two sexes to oxidize various important substrates. Both sexes contain three adipokinetic peptides in their corpora cardiaca; the amount of each peptide in female grasshoppers is higher than in males.Thus, despite some differences listed above, both sexes appear to have sufficient substrates and the necessary endocrine complement to engage in flight. It seems more likely, from the morphometric data above, that the chief reason for flightlessness is that P. morbillosus females cannot produce sufficient lift for flight; alternatively, the neuronal functioning associated with the flight muscles may be impaired in females.
Morphological factors determining salt tolerance in citrus seedlings: the shoot to root ratio modulates passive root uptake of chloride ions and their accumulation in leaves
Authors: Moya J. L. , Primo‐Millo E. , Talon M. 
Published: March 2003

ABSTRACTThe results presented in this work were obtained with two citrus genotypes, the chloride‐tolerant Cleopatra mandarin (Citrus reshni Hort. ex Tan.) and the chloride‐sensitive Carrizo citrange [Citrus sinensis (L.) Osb. ×Poncirus trifoliata (L.) Raf.]. The data show that chloride uptake under salinization is driven by passive forces. In both species, net rates of chloride root uptake increased linearly, without saturation, with the increase of external NaCl concentrations (30–240 mol m–3). Uptake rates, on a μg g root dry weight–1 h–1 basis, in Cleopatra and Carrizo decreased (from 38 to 21) and increased (from 21 to 35), respectively, with the increase (about three‐fold) of the shoot to root ratio. With the appropriate shoot to root ratio in each genotype, it was demonstrated that at identical external doses of NaCl, Cl– uptake rates and Cl– xylem concentrations in the two species were very similar. Root pruning and defoliation showed that the amount of chloride taken by the plant was a function of the size of the root system, whereas leaf chloride concentration, the parameter responsible for salt damage, was dependent upon leaf biomass. Measurements of water transpiration suggested that chloride root uptake and leaf accumulation might be linked to water absorption and transpiration rates, respectively. The data indicate that plant morphology is a crucial factor determining salt‐tolerance in citrus.
The effects of high temperature on isoprene synthesis in oak leaves
Authors: Singsaas E. L. , Sharkey T. D. 
Published: March 2003

ABSTRACTIsoprene emission from plants is highly temperature sensitive and is common in forest canopy species that experience rapid leaf temperature fluctuations. Isoprene emission declines with temperature above 35 °C but the temperature at which the decline begins varies between 35 and 44 °C. This variability is caused by the rate at which leaf temperature is increased during measurement with lower temperatures associated with longer measurement cycles. To investigate this we exposed leaves of red oak (Quercus rubra L.) to temperature regimes of 35–45 °C for periods of 20–60 min. Isoprene emission increased during the first 10 min of high temperature exposure and then decreased over the next 10 min until it reached steady state. This phenomenon was common at temperatures above 35 °C but was not noticeable at temperatures below that. The response was reversible within 30 min by lowering leaf temperature to 30 °C. Because there is no storage of isoprene inside the leaf, this behaviour indicates regulation of isoprene synthesis in the leaf. We demonstrated that the variability in isoprene decline results from regulation and explains the variability in the temperature response. This is consistent with our theory that isoprene protects leaves from damage caused by rapid temperature fluctuations.
Distribution of Zn in functionally different leaf epidermal cells of the hyperaccumulator Thlaspi caerulescens
Authors: Frey B. , Keller C. , Zierold K. 
Published: March 2003

ABSTRACTThe aim of this study was to show the potential of Thlaspi caerulescens in the cleaning‐up of a moderately Zn ‐contaminated soil and to elucidate tolerance mechanisms at the cellular and subcellular level for the detoxification of the accumulated metal within the leaf. Measured Zn concentrations in shoots were high and reached a maximum value of 83 mmol kg−1 dry mass, whereas total concentrations of Zn in the roots were lower (up to 13 mmol kg−1). In order to visualize and quantify Zn at the subcellular level in roots and leaves, ultrathin cryosections were analysed using energy‐dispersive X‐ray micro‐analysis. Elemental maps of ultrathin cryosections showed that T. caerulescens mainly accumulated Zn in the vacuoles of epidermal leaf cells and Zn was almost absent from the vacuoles of the cells from the stomatal complex, thereby protecting the guard and subsidiary cells from high Zn concentrations. Observed patterns of Zn distribution between the functionally different epidermal cells were the same in both the upper and lower epidermis, and were independent of the total Zn content of the plant. Zinc stored in vacuoles was evenly distributed and no Zn‐containing crystals or deposits were observed. From the elemental maps there was no indication that P, S or Cl was associated with the high Zn concentrations in the vacuoles. In addition, Zn also accumulated in high concentrations in both the cell walls of epidermal cells and in the mesophyll cells, indicating that apoplastic compartmentation is another important mechanism involved in zinc tolerance in the leaves of T. caerulescens.
The effect of ozone in Scots pine (Pinus sylvestris L.): gene expression, biochemical changes and interactions with UV‐B radiation
Authors: Zinser C. , Jungblut T. , Heller W. , Seidlitz H. K. , Schnitzler J.‐P. , Ernst D. , Jr H. Sandermann 
Published: March 2003

ABSTRACTIncreased levels of both ozone and ultraviolet‐B radiation (UV‐B) are typical for high‐altitude sites. Here we report on interactive effects of both stresses on Scots pine (Pinus sylvestris L.). Scots pine seedlings were exposed in a phytotron to a simulated outdoor climate. To assess effects of ozone and of UV‐B radiation on the plants, ozone was added at ambient or at twice‐ambient levels, and UV‐B was eliminated or added at a low ambient level. Visible needle damage became apparent at enhanced ozone concentrations after 10 d of exposure and increased continuously. The accumulated exposure over a threshold value of 40 nL L−1 ozone (AOT40) revealed that an ozone exposure dose of 10 μL L−1 h was necessary for the development of needle injury, regardless of the UV‐B conditions. Cinnamyl alcohol dehydrogenase (CAD) and stilbene synthase (STS) have been reported to be induced by ozone. The mRNAs of these stress‐related enzymes were induced only under twice‐ambient ozone concentrations. Ozone‐induced transient STS transcript levels reached their maximal values between day 1 and day 5, and were more pronounced in the presence of UV‐B. Similarly, pinosylvin, as well as pinosylvin methyl ether contents, showed moderate transient increases under these conditions. In contrast, CAD mRNA content and CAD enzyme activity increased continuously under enhanced ozone concentrations. Additional UV‐B resulted in suppressed transcript level and enzymatic activity of CAD. The data indicate that in conifer needles, at the level of gene expression, there is an interaction between responses to UV‐B and ozone.
Xylem sap flow and stem hydraulics of the vesselless angiosperm Drimys granadensis (Winteraceae) in a Costa Rican elfin forest
Authors: Feild T. S. , Holbrook N. M. 
Published: March 2003

ABSTRACTFor decades, botanists have considered Winteraceae as the least modified descendents of the first angiosperms primarily because this group lacks xylem vessels. Because of a presumed high resistance of a tracheid‐based vascular system to water transport, Winteraceae have been viewed as disadvantaged relative to vessel‐bearing angiosperms. Here we show that in a Costa Rican cloud forest, stem hydraulic properties, sapwood area‐ and leaf area‐specific hydraulic conductivities of Drimys granadensis L. (Winteraceae) are similar to several co‐occurring angiosperm tree species with vessels. In addition, D. granadensis had realized midday transpiration rates comparable to most vessel‐bearing trees. Surprisingly, we found that D. granadensis transpired more water at night than during the day, with actual water loss being correlated with wind speed. The failure of stomata to shut at night may be related to the occlusion of stomatal pores by cutin and wax. Our measurements do not support the view that absence of xylem vessels imposes limitations on water transport above those for other vesselled plants in the same environment. This, in turn, suggests that a putative return to a tracheid‐based xylem in Winteraceae may not have required a significant loss of hydraulic performance.
Two distinct regions of response drive differential growth in Vigna root electrotropism
Authors: Wolverton C. , Mullen J. L. , Ishikawam H. , Evans M. L. 
Published: March 2003

ABSTRACTAlthough exogenous electric fields have been reported to influence the orientation of plant root growth, reports of the ultimate direction of differential growth have been contradictory. Using a high‐resolution image analysis approach, the kinetics of electrotropic curvature in Vigna mungo L. roots were investigated. It was found that curvature occurred in the same root toward both the anode and cathode. However, these two responses occurred in two different regions of the root, the central elongation zone (CEZ) and distal elongation zone (DEZ), respectively. These oppositely directed responses could be reproduced individually by a localized electric field application to the region of response. This indicates that both are true responses to the electric field, rather than one being a secondary response to an induced gravitropic stimulation. The individual responses differed in the type of differential growth giving rise to curvature. In the CEZ, curvature was driven by inhibition of elongation, whereas curvature in the DEZ was primarily due to stimulation of elongation. This stimulation of elongation is consistent with the growth response of the DEZ to other environmental stimuli.