801 research outputs found

    ALEX Fetal Medicine Foundation reference ranges for umbilical artery and middle cerebral artery pulsatility index and cerebroplacental ratio

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    Objective: To develop reference ranges with gestational age for the pulsatility index in the umbilical artery (UA-PI) and fetal middle cerebral artery (MCA-PI and the cerebroplacental ratio (MCA-PI / UA-PI) and examine the maternal characteristics and medical history that affect these measurements. Patients and methods: This was a cross-sectional study of 72,417 pregnancies undergoing routine ultrasound examination at 20+0 to 22+6 weeks’ gestation (n=3,712), or at 31+0 to 33+6 weeks (n=29,035) or at 35+0 to 36+6 weeks (n=37,282) or at 41+0 to 41+6 weeks (n=2,388). For the purpose of this study we included data for only one of the second or third trimester visits. The inclusion criteria were singleton pregnancy, dating by fetal crown-rump length at 11+0 to 13+6 weeks’ gestation, livebirth of morphologically normal neonate and ultrasonographic measurements by sonographers that had received the Fetal Medicine Foundation Certificate of competence in Doppler ultrasound. Since the objectives of the study were to establish reference ranges, rather than normal ranges, and to examine factors from maternal characteristics and medical history that affect these measurements, we included all pregnancies having routine ultrasound examinations irrespective of whether the mothers had a pre-existing medical condition, such as diabetes mellitus, or a pregnancy complication, such as preeclampsia or suspected fetal growth restriction. Median and standard deviation (SD) models were fitted between UA-PI, MCA-PI and CPR and gestational age. Assessment of goodness of fit of the models was by inspection of quantile to quantile (q-q) plots of z-scores calculated via the mean and SD models. The distributions of MCA PI, UA PI and CPR z-scores were examined in relation to maternal characteristics and medical history. Results: The relationship between the median and gestation age was linear for UA-PI and cubic for MCA-PI and CPR and the SD was log quadratic for all three. MCA-PI and CPR increased with gestational age from 20 weeks’ gestation to reach a peak at around 32 and 34 weeks’ respectively, and decreased thereafter, whereas UA-PI decreased linearly with gestation from 20 to 42 weeks. Compared to the general population, significant deviations in MoM values of UA-PI, MCA-PI and CPR were observed in subgroups of maternal age, BMI, racial origin, method of conception and parity. Conclusion: The study established new reference ranges of UA-PI, MCA-PI and CPR with gestational age and reports maternal characteristics and medical history that affect these measurements

    Comparison of screening for pre-eclampsia at 31-34 weeks' gestation by sFlt-1/PlGF ratio and a method combining maternal factors with sFlt-1 and PlGF

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    Objective: To estimate the patient-specific risk of preeclampsia (PE) at 31-34 weeks’ gestation by a combination of maternal characteristics and medical history with multiple of the median (MoM) values of serum placental growth factor (PLGF) and serum soluble fms-like tyrosine kinase-1 (sFLT-1) and compare the performance of screening to that achieved by the sFLT-1 to PLGF ratio. Methods: This was a prospective observational study in women attending for a third-trimester ultrasound scan at 31-34 weeks as part of routine pregnancy care. We estimated the performance of screening of PE with delivery within four weeks of assessment (PE at <4 weeks) and PE from four weeks after assessment and up to 40 weeks’ gestation (PE at 4w-40GW) in screening by the sFLT-1 to PLGF ratio and by a to PLGF ratio and by a method utilizing Bayes theorem to combine maternal factors and MoM values of sFLT-1 and PLGF. The significance of difference in performance of screening between the method utilising Bayes theorem and that of the sFLT-1 to PLGF ratio was assessed by comparison of the areas under the receiver operating characteristic curves (AUROC). Results: The study population of 8,063 singleton pregnancies included 231 (2.9%) that subsequently developed PE. In the prediction of delivery with PE at <4 weeks the performance of the method utilising Bayes theorem was similar to that of the sFLT-1 to PLGF (AUROC: 0.987, 95%CI 0.979-0.995 vs. 0.988, 95%CI: 0.981-0.994; p=0.961). and at fixed fixed screen positive rate (SPR) of 3.9% the detection rate (DR) was 87.1% for both methods. In contrast, the performance of screening for delivery with PE at 4w-40GW was better with the method utilising Bayes theorem than with the sFLT-1 to PLGF ratio (AUROC: 0.884, 95%CI 0.854-0.914 vs. 0.818, 95%CI: 0.775--0.860 ; p<0.0001) and at total fixed SPR of 25.7% the DRs were 84.4% vs. 73.0%. Conclusion: At 31-34 weeks’ gestation the performance of screening for PE at <4 weeks from assessment by the method utilising Bayes theorem is similar to that of the sFLT-1 to PLGF ratio, but the former is superior to the latter in prediction of PE >>4 weeks

    Advances in genome-wide RNAi cellular screens: a case study using the Drosophila JAK/STAT pathway

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    BACKGROUND: Genome-scale RNA-interference (RNAi) screens are becoming ever more common gene discovery tools. However, whilst every screen identifies interacting genes, less attention has been given to how factors such as library design and post-screening bioinformatics may be effecting the data generated. RESULTS: Here we present a new genome-wide RNAi screen of the Drosophila JAK/STAT signalling pathway undertaken in the Sheffield RNAi Screening Facility (SRSF). This screen was carried out using a second-generation, computationally optimised dsRNA library and analysed using current methods and bioinformatic tools. To examine advances in RNAi screening technology, we compare this screen to a biologically very similar screen undertaken in 2005 with a first-generation library. Both screens used the same cell line, reporters and experimental design, with the SRSF screen identifying 42 putative regulators of JAK/STAT signalling, 22 of which verified in a secondary screen and 16 verified with an independent probe design. Following reanalysis of the original screen data, comparisons of the two gene lists allows us to make estimates of false discovery rates in the SRSF data and to conduct an assessment of off-target effects (OTEs) associated with both libraries. We discuss the differences and similarities between the resulting data sets and examine the relative improvements in gene discovery protocols. CONCLUSIONS: Our work represents one of the first direct comparisons between first- and second-generation libraries and shows that modern library designs together with methodological advances have had a significant influence on genome-scale RNAi screens

    A modern pollen record from the central Gulf of California

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    As one facet of an effort to tie the pollen record of central Gulf of California deep cores to modern analogs, pollen was analyzed in the uppermost 150-200 years of varved core 7807-1410 taken nearby. Sampling at 2- to 8-year resolution yielded a noncomplacent record, suggesting pollen in these sediments may be a potential high resolution proxy record of short-term climatic events. The pollen spectrum as a whole matches that of upper-most DSDP Site 480 (means of all samples). Lack of a ratio or influx shift following damming of local rivers and a surplus of low-spine Compositae pollen relative to mainland sites support Baumgartner's theory that terrigenous influx to the site is largely aeolian and also suggest that a significant fraction of the pollen influx may come from Baja California

    Screening for pre-eclampsia by maternal factors and biomarkers at 11-13 weeks' gestation

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    Objective: To examine the performance of screening for early-, preterm- and term-preeclampsia (PE) at 11 13 weeks’ gestation by maternal factors and combinations of mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), serum placental growth factor (PLGF) and serum pregnancy associated plasma protein A (PAPP A). Methods The data for this study were derived from three previously reported prospective non intervention screening studies at 11+0 – 13+6 weeks’ gestation in a combined total of 61,174 singleton pregnancies, including 1,770 (2.9%) that developed PE. Bayes theorem was used to combine the prior distribution of the gestational age at delivery with PE, obtained from maternal characteristics, with various combinations of biomarker multiple of the median (MoM) values to derive the p patient specific risks of delivery with PE at <37 weeks’ gestation. The performance of such screening was estimated. Results In pregnancies that develop ed PE , compared to those without PE, the MoM values of UtA-PI and MAP were increased and PAPP A and PLGF were decreased and the deviation from normal was greater for early than late PE for all four biomarkers. Combined screening by maternal factors, UtA-PI, MAP and PLGF predicted 90% of early PE, 75% of preterm PE and 4 1 % of term PE, at screen positive rate of 10%; inclusion of PAPP A did not improve the performance of screening The performance of screening depended on the racial origin of the women; in screening by a combination of maternal factors, MAP, UtA-PI and PLGF and use of the risk cut off of 1 in 10 0 for PE at <37 weeks in Caucasian women, the screen positive rate was 10% and detection rates for early --, preterm and term PE were 88%, 69% and 40%, respectively. With the same method of screening and risk cut off in women of Afro Caribbean racial origin, the screen positive rate was 34% and detection rates for early --, preterm and term PE were 100%, 92% and 75%, respectively. Conclusion Screening by maternal factors and biomarkers at 11-13 weeks’ gestation can identify a high proportion of pregnancies that develop early- and preterm-PE

    Toxic effect of herbicides used for water hyacinth control on two insects released for its biological control in South Africa

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    The integrated control of water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae) has become necessary in South Africa, as biological control alone is perceived to be too slow in controlling the weed. In total, seven insect biological control agents have been released on water hyacinth in South Africa. At the same time, herbicides are applied by the water authorities in areas where the weed continues to be troublesome. This study investigated the assumption that the two control methods are compatible by testing the direct toxicity of a range of herbicide formulations and surfactants on two of the biological control agents released against water hyacinth, the weevil, Neochetina eichhorniae Warner (Coleoptera: Curculionidae) and the water hyacinth mirid,Eccritotarsus catarinensis (Carvalho) (Hemiptera: Miridae). A number of the formulations used resulted in significant mortality of the mirid and the weevil. Products containing 2,4-D amine and diquat as active ingredients caused higher mortality of both agents (up to 80% for the mirid) than formulations containing glyphosate. Furthermore, when surfactants were added to enhance herbicide efficiency, it resulted in increased toxicity to the insects. We recommend that glyphosate formulations should be used in integrated control programmes, and that surfactants be avoided in order to reduce the toxic nature of spray formulations to the insect biological control agents released against water hyacinth

    Aspirin for evidence-based preeclampsia prevention trial: effect of aspirin in prevention of preterm preeclampsia in subgroups of women according to their characteristics and medical and obstetrical history.

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    Objective: To examine whether there are differences in the effect of aspirin on the incidence of preterm-PE in the ASPRE trial in subgroups defined according to maternal characteristics and medical and obstetrical history. Study design: This was a secondary analysis of data from the ASPRE trial. In ASPRE women with singleton pregnancies had screening by means of an algorithm that combines maternal factors and biomarkers at 11-13 weeks’ gestation. Those with an estimated risk for preterm-PE of >1 in 100 were invited to participate in a double-blind trial of aspirin (150 mg/day) vs. placebo from 11 to 14 until 36 weeks’ gestation. Aspirin was associated with a significant reduction in the incidence of preterm-PE with delivery at 90% of the prescribed medication. Results are presented as forest plot with P values for the interaction effects, group sizes, event counts and estimated odds ratios. We examined whether the test of interaction was significant at the 5% level with a Bonferroni adjustment for multiple comparisons. Results: There was no evidence of heterogeneity in the aspirin effect in subgroups defined according to maternal characteristics and obstetrical history. In participants with chronic hypertension preterm-PE occurred in 10.2% (5/49) in the aspirin group and in 8.2% (5/61) in the placebo group (adjusted odds ratio 1.29, 95% confidence interval, 0.33 to 5.12); the respective values in those without chronic hypertension were 1.1% (8/749) in the aspirin group and 3.9% (30/761) in the placebo group (adjusted odds ratio 0.27, 95% confidence interval, 0.12 to 0.60). In all participants with adherence of >90% the adjusted odds ratio in the aspirin group was 0.24 (95% CI 0.09 to 0.65), in the subgroup with chronic hypertension it was 2.06 (95% CI 0.40 to 10.71) and in those without chronic hypertension it was 0.05 (95% CI 0.01 to 0.41). For the complete data set the test of interaction was not significant at the 5% level (p=0.055), but in those with adherence >90%, after adjustment for multiple comparisons, the interaction was significant at the 5% level (p=0.0019). Conclusions: The beneficial effect of aspirin in the prevention of preterm preeclampsia may not apply in pregnancies with chronic hypertension. There was no evidence of heterogeneity in the aspirin effect in subgroups defined according to maternal characteristics and obstetrical history

    Leadership and the media: Gendered framings of Julia Gillard's ‘sexism and misogyny’ speech

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    This article analyses Australian media portrayals of former Australian Prime Minister Julia Gillard's ‘sexism and misogyny’ speech to parliament in October 2012. Our analysis reveals that coverage of the speech comprised three principal gendered framings: strategic attack, uncontrolled emotional outpouring and hypocrisy. We argue that these framings demonstrate the role the media plays as a gendered mediator, perpetuating the gender double bind that constrains female political leaders, as they negotiate the demand to demonstrate masculine leadership attributes without tarnishing the feminine qualities expected of them. In this instance, gendered media framings limited the saliency of Gillard's speech, curtailed calls for wider introspection on Australian political culture and further disassociated women from political leadership

    Experiences and Outcomes of Preschool Physical Education: an analysis of developmental discourses in Scottish curricular documentation

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    This article provides an analysis of developmental discourses underpinning preschool physical education in Scotland's Curriculum for Excellence. Implementing a post-structural perspective, the article examines the preschool experiences and outcomes related to physical education as presented in the Curriculum for Excellence ‘health and wellbeing’ documentation. The article interrogates the ways in which developmental discourses are evident throughout this and related documentation and how these discourses might ‘work’ to produce specific effects on practitioners and children as they are deployed and taken up in Scottish preschool education contexts. This analysis involves speculating about potential consequences for practitioners' and children's experiences and subjectivities. In conclusion, it is suggested that practitioners should critically engage with the curriculum, as uncritical acceptance of the discourses underpinning it could lead to practices that may have negative consequences. Furthermore, the article proposes that future research should investigate the ways in which the discourses privileged in the Curriculum for Excellence ‘health and wellbeing’ documentation are taken up and negotiated in Scottish preschool settings

    Magnetic Field Generation in Stars

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    Enormous progress has been made on observing stellar magnetism in stars from the main sequence through to compact objects. Recent data have thrown into sharper relief the vexed question of the origin of stellar magnetic fields, which remains one of the main unanswered questions in astrophysics. In this chapter we review recent work in this area of research. In particular, we look at the fossil field hypothesis which links magnetism in compact stars to magnetism in main sequence and pre-main sequence stars and we consider why its feasibility has now been questioned particularly in the context of highly magnetic white dwarfs. We also review the fossil versus dynamo debate in the context of neutron stars and the roles played by key physical processes such as buoyancy, helicity, and superfluid turbulence,in the generation and stability of neutron star fields. Independent information on the internal magnetic field of neutron stars will come from future gravitational wave detections. Thus we maybe at the dawn of a new era of exciting discoveries in compact star magnetism driven by the opening of a new, non-electromagnetic observational window. We also review recent advances in the theory and computation of magnetohydrodynamic turbulence as it applies to stellar magnetism and dynamo theory. These advances offer insight into the action of stellar dynamos as well as processes whichcontrol the diffusive magnetic flux transport in stars.Comment: 41 pages, 7 figures. Invited review chapter on on magnetic field generation in stars to appear in Space Science Reviews, Springe
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