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The mesosphere/lower thermosphere (MLT, 80–100 km) region is an important boundary between Earth's atmosphere below and space above and may act as a sensitive indicator for anthropogenic climate change. Existing observational and modeling studies have shown the middle atmosphere and the MLT is cooling and contracting because of increasing greenhouse gas emissions. However, trend analyses are highly sensitive to the time periods covered, their length, and the measurement type and methodology used. We present for the first time the linear and 11‐year solar cycle responses in the meteor ablation altitude distributions observed by 12 meteor radars at different locations. Decreasing altitudes were seen at all latitudes (linear trends varying from −10.97 to −817.95 m dec−1), and a positive correlation with solar activity was seen for most locations. The divergence of responses at high latitudes indicates an important and complex interplay between atmospheric changes and dynamics at varying time scales. Plain Language Summary High up in our atmosphere lies the mesosphere/lower thermosphere region (80–100 km); an important transition zone between the atmosphere below and space above. Existing studies indicate that this region is changing (cooling and contracting) in response to increasing greenhouse gas emissions, quite unlike the net warming we see near the surface. However these trend studies are often highly sensitive to choice and length of time period covered, and the methodology and type of measurements used. Here we present for the first time a self‐consistent methodology applied to 12 different meteor radar station datasets located at a diverse range of latitudes. We looked at changes in the mean peak altitude of individual meteoroid detections, and found decreasing peak altitudes at all locations examined (linear trends varying from −10.97 to −817.95 m decade−1) consistent with a global cooling and contracting of the upper atmosphere. We also examined the response to the 11‐year solar cycle and found a positive correlation with solar activity (i.e., increased meteoroid peak altitudes during solar maximum, and vice versa) for low and mid‐latitude locations. However we found an anti‐correlation at high latitudes suggestive of an important and complex interplay between atmospheric changes and dynamics at varying time scales. Key Points Use of geographically diverse meteor radar peak detection altitudes to assess long‐term and 11‐year solar cycle (SC) trends in mesopause region The altitude of observed peak meteor height has decreased over time at all locations, regardless of latitude and data set Positive correlation at low‐ and mid‐latitude locations with the 11‐year SC, but more complex response at high‐latitudes

Non-invasive cross-sectional imaging techniques play a crucial role in the assessment of the varied manifestations of vascular disease. Vascular imaging encompasses a wide variety of pathology. Designing vascular imaging protocols can be challenging owing to the non-uniform velocity of blood in the aorta, differences in cardiac output between patients, and the effect of different disease states on blood flow. In this review, we provide the rationale behind—and a practical guide to—designing and implementing straightforward vascular computed tomography (CT) and magnetic resonance imaging (MRI) protocols.Teaching Points• There is a wide range of vascular pathologies requiring bespoke imaging protocols.• Variations in cardiac output and non-uniform blood velocity complicate vascular imaging.• Contrast media dose, injection rate and duration affect arterial enhancement in CTA.• Iterative CT reconstruction can improve image quality and reduce radiation dose.• MRA is of particular value when imaging small arteries and venous studies.

Background Cardiotocography (CTG) is a screening test used to detect fetal hypoxia in labour. It has a high false positive rate resulting in many potentially unnecessary caesarean sections. Fetal blood sampling (FBS) is a second-line test of the acid-base status of the fetus. It is used to provide either reassurance that it is safe for labour to continue or objective evidence of compromise so that delivery can be expedited. Digital fetal scalp stimulation (dFSS) to elicit a fetal heart rate acceleration is an alternative less invasive second-line test of fetal wellbeing. This study aims to provide robust evidence on the role of these two second-line tests in assessing fetal wellbeing and potentially preventing operative delivery. Methods A multi-centre parallel group randomised controlled trial (RCT) is planned in four maternity centres in Ireland. The study aims to recruit 2500 nulliparous women with a term (≥37+0 weeks) singleton pregnancy who require a second-line test of fetal wellbeing in labour due to an abnormal CTG. Women will be allocated randomly to dFSS or FBS on a 1:1 ratio. The primary outcome is caesarean section. With 1250 women in each arm, the study will have 90% power to detect a difference of 5–6%, at a two-sided alpha significance level of 5%, assuming a caesarean section rate of at least 20% in the dFSS group. Discussion If the proposed study shows evidence that dFSS is a safe, reliable and effective alternative to FBS, this would have ground-breaking implications for labour management worldwide. It could potentially lead to a reduction in invasive procedures and emergency caesarean sections. Trial registration ClinicalTrials.gov NCT05306756. Registered on 31 March 2022. The trial commenced enrolment on 10 May 2022. Ethical committee approval has been granted by the Research Ethics Committee (REC) of each hospital: Dublin/CWIUH REC: 12.06.2019; Cork/UCC REC: 29.11.2019; Galway/NUIG REC: 06.09.2019; Limerick/UL REC: 30.09.2019.

A wildfire burned through a previously sampled research site, allowing pre- and post-burn measurements of the forest floor, soils, and soil leaching near Lake Tahoe, Nevada. Fire and post-fire erosion caused large and statistically significant (P less than or equal to 0.05) losses of C, N, P, S, Ca, and Mg from the forest floor. There were no statistically significant effects on mineral soils aside from a decrease in total N in the surface (A11) horizon, an increase in pH in the A11 horizon, and increases in water-extractable SO4(2-) in the A11 and A12 horizons. Burning caused consistent but nonsignificant increases in exchangeable Ca(2+) in most horizons, but no consistent or statistically significant effects on exchangeable K(+) or Mg(2+), or on Bray-, bicarbonate-, or water-extractable P concentrations. Before the burn, there were no significant differences in leaching, but during the first winter after the fire, soil solution concentrations of NH4(+), NO3(-), ortho-P, and (especially) SO4(2-) were elevated in the burned area, and resin lysimeters showed significant increases in the leaching of NH4(+) and mineral N. The leaching losses of mineral N were much smaller than the losses from the forest floor and A11 horizons, however. We conclude that the major short-term effects of wildfire were on leaching whereas the major long-term effect was the loss of N from the forest floor and soil during the fire.

Gravity wave activity in the upper stratosphere and lower mesosphere (USLM) is investigated using temperature data retrieved from a Rayleigh lidar at Davis, Antarctica (69°S, 78°E) during the 2007 and 2008 winters. The temporal and height variabilities of waves with ground‐based periods greater than 2 h and vertical wavelengths between 4 km and 20 km are analyzed. Stratospheric gravity wave potential energy per unit mass shows a weaker correlation with stratospheric winds at Davis than that reported in the Arctic. Gravity waves dissipate above 40 km during winter, while there is no dissipation in the autumn mesosphere. A separate analysis of gravity waves with ground‐based periods of 2–6 h revealed lower dissipation in the winter mesosphere. The seasonal cycle of gravity wave activity is evident throughout the USLM, with peak activity observed during winter. The gravity wave potential energy and vertical wavenumber power spectral density at Davis are similar to that recorded at other high‐latitude sites. Key Points Gravity wave dissipation in the winter Antarctic mesosphere Seasonal cycle of wave activity in the USLM with winter peak Correlation between stratosphere u wind speed and energy lower than in Arctic

I have used cellular and molecular genetic and bioinformatic approaches to characterise the components of the pollen coat in plants of the family Brassicaceae, including Arabidopsis thaliana and several brassicas including Brassica napus, B. oleracea, and B. rapa. The pollen coat in these species is mostly made up of a unique mixture of lipids that is highly enriched in acylated compounds, such as sterol esters and phospholipids. These acyl lipids are characterised by an unusually high degree of saturation. The fatty acids typically contain 70-90% saturated acyl residues such as myristate, palmitate, and stearate. The major sterol components of the pollen coat are saturated fatty acyl esters of stigmasterol, campesterol, and campestdienol. In addition to lipids, the second major component of the pollen coat is a specific group of proteins that is dominated by a family of proteins that we term pollenins. Although pollenins are by far the major protein components of the pollen coat of members of the Brassicaceae, proteomic analysis reveals that there are several additional protein components, including lipases, protein kinases, a pectin esterase, and a caleosin. The biosynthesis of these lipids and proteins and their significance for overall pollen function are reviewed and discussed.

Two years of Very High Frequency (VHF) radar echo power observations are used to examine the structure and variability of the tropopause at Davis, Antarctica. Co-located radiosonde and ozonesonde launches provide data with which to calculate the lapse-rate and chemical tropopauses. The radar tropopause, defined as the maximum vertical gradient of echo return power, can be used as a definition of the Antarctic tropopause throughout the year under all meteorological conditions. During the extended summer period of December–April (DJFMA) inclusive, radar tropopauses are (0.2 0.4) km lower than radiosonde lapse-rate (i.e. the World Meteorological Organisation – WMO) tropopauses and during the extended winter period of June–October (JJASO) inclusive, the radar tropopauses are (0.8 1.0) km lower. A potential vorticity tropopause is defined as the altitude of the −2 PVU surface (where 1 PVU = 106 m2 s−1 K kg−1). This is (0.3 0.5) km lower than the radar tropopause during DJFMA and (0.5 1.0) km lower during JJASO. The radar, potential vorticity and ozone tropopauses decrease in altitude during increasingly strong cyclonic conditions, in contrast to the radiosonde WMO tropopause which remains nearly constant. During strong JJASO cyclonic conditions, there are large (several km) differences between WMO tropopause altitudes and radar tropopause altitudes. A seasonal cycle in tropopause fold occurrence is observed, with approximately a three-fold increase during JJASO.

Oncogenic signaling in melanocytes results in oncogene-induced senescence (OIS), a stable cell-cycle arrest frequently characterized by a bi- or multinuclear phenotype that is considered as a barrier to cancer progression. However, the long-sustained conviction that senescence is a truly irreversible process has recently been challenged. Still, it is not known whether cells driven into OIS can progress to cancer and thereby pose a potential threat. Here, we show that prolonged expression of the melanoma oncogene N-RAS 61K in pigment cells overcomes OIS by triggering the emergence of tumor-initiating mononucleated stem-like cells from senescent cells. This progeny is dedifferentiated, highly proliferative, anoikis-resistant and induces fast growing, metastatic tumors. Our data describe that differentiated cells, which are driven into senescence by an oncogene, use this senescence state as trigger for tumor transformation, giving rise to highly aggressive tumor-initiating cells. These observations provide the first experimental in vitro evidence for the evasion of OIS on the cellular level and ensuing transformation.

Wind observations obtained between 1995 and 2011 using the MF radar at Davis have been used to demonstrate the modifying role the quasi‐biennial oscillation (QBO) plays on some aspects of interhemispheric coupling identified by previous authors. The response of the meridional wind in the southern summer polar MLT to changes in winter stratospheric planetary wave activity is shown to change sign according to the phase of the QBO. The time delay associated with the coupling is also shown to vary with QBO phase, with an eastward QBO providing a more rapid response. Coupling to the MLT meridional winds is strongest in January. Parts of the mechanism currently proposed have been tested using UKMO assimilated observations. The signatures of some aspects of this mechanism are present in the data. However, some differences to the mechanism are also apparent, in particular the effectiveness of the mechanism near the equator. An explanation for the QBO modulation of the MLT wind response to interhemispheric coupling is proposed on the basis of these differences. Key Points Coupling from winter stratosphere to summer polar MLT identified in wind QBO found to modulate the interhemispheric coupling mechanism

Aims/hypothesis Studies have shown a relationship between pre-eclampsia and later coronary artery disease. This study investigated whether there is a relationship between pre-eclampsia and the development of type 2 diabetes in mothers and their babies and how this is affected by infant birthweight. Subjects and methods This was an intergenerational cohort study. The study population comprised 7,187 mothers who gave birth and 8,648 babies who were born in Dundee, Scotland between 1952 and 1958. Their later diabetic status was defined from 1980 to 2003 by linkage to population-based datasets. Results There were 810 (11.3%) mothers with pre-eclampsia and 745 (10.4%) who subsequently developed type 2 diabetes. Logistic regression showed an increased risk of developing type 2 diabetes for mothers with pre-eclampsia, unadjusted odds ratio (OR) 1.37 (95% CI 1.10-1.71), p = 0.005. This relationship persisted after adjustment for infant birthweight, OR 1.40 (95% CI 1.12-1.75), p = 0.003. Of the babies born between 1952 and 1958, 221 (2.6%) had developed type 2 diabetes, 137 of them male (2.9% of male subjects in study population) and 84 female (2.2% of female subjects). The relationship between pre-eclampsia in the mother and the risk of type 2 diabetes in the offspring did not reach statistical significance, OR 1.38 (95% CI 0.90-2.10). Babies with birthweight in the lowest quintile (adjusted for sex, gestation and birth order) had an increased risk of developing type 2 diabetes, OR for lowest quintile vs highest quintile 1.84 (95% CI 1.24-2.72), p = 0.002. Conclusions/interpretation Pre-eclampsia is associated with increased risk of developing type 2 diabetes in the mother, but birthweight is a more important determinant of future risk for the offspring.