The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018.

Global aviation operations contribute to anthropogenic climate change via a complex set of processes that lead to a net surface warming. Of importance are aviation emissions of carbon dioxide (CO2), nitrogen oxides (NOx), water vapor, soot and sulfate aerosols, and increased cloudiness due to contrail formation. Aviation grew strongly over the past decades (1960-2018) in terms of activity, with revenue passenger kilometers increasing from 109 to 8269 billion km yr-1, and in terms of climate change impacts, with CO2 emissions increasing by a factor of 6.8 to 1034 Tg CO2 yr-1. Over the period 2013-2018, the growth rates in both terms show a marked increase. Here, we present a new comprehensive and quantitative approach for evaluating aviation climate forcing terms. Both radiative forcing (RF) and effective radiative forcing (ERF) terms and their sums are calculated for the years 2000-2018. Contrail cirrus, consisting of linear contrails and the cirrus cloudiness arising from them, yields the largest positive net (warming) ERF term followed by CO2 and NOx emissions. The formation and emission of sulfate aerosol yields a negative (cooling) term. The mean contrail cirrus ERF/RF ratio of 0.42 indicates that contrail cirrus is less effective in surface warming than other terms. For 2018 the net aviation ERF is +100.9 milliwatts (mW) m-2 (5-95% likelihood range of (55, 145)) with major contributions from contrail cirrus (57.4 mW m-2), CO2 (34.3 mW m-2), and NOx (17.5 mW m-2). Non-CO2 terms sum to yield a net positive (warming) ERF that accounts for more than half (66%) of the aviation net ERF in 2018. Using normalization to aviation fuel use, the contribution of global aviation in 2011 was calculated to be 3.5 (4.0, 3.4) % of the net anthropogenic ERF of 2290 (1130, 3330) mW m-2. Uncertainty distributions (5%, 95%) show that non-CO2 forcing terms contribute about 8 times more than CO2 to the uncertainty in the aviation net ERF in 2018. The best estimates of the ERFs from aviation aerosol-cloud interactions for soot and sulfate remain undetermined. CO2-warming-equivalent emissions based on global warming potentials (GWP* method) indicate that aviation emissions are currently warming the climate at approximately three times the rate of that associated with aviation CO2 emissions alone. CO2 and NOx aviation emissions and cloud effects remain a continued focus of anthropogenic climate change research and policy discussions.

Low loss Ge-on-Si waveguides operating in the 8-14 µm atmospheric transmission window.

Germanium-on-silicon waveguides were modeled, fabricated and characterized at wavelengths ranging from 7.5 to 11 µm. Measured waveguide losses are below 5 dB/cm for both TE and TM polarization and reach values of ∼ 1 dB/cm for ≥ 10 µm wavelengths for the TE polarization. This work demonstrates experimentally for the first time that Ge-on-Si is a viable waveguide platform for sensing in the molecular fingerprint spectral region. Detailed modeling and analysis is presented to identify the various loss contributions, showing that with practical techniques losses below 1 dB/cm could be achieved across the full measurement range.

Implications of possible interpretations of 'greenhouse gas balance' in the Paris Agreement.

The main goal of the Paris Agreement as stated in Article 2 is 'holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C'. Article 4 points to this long-term goal and the need to achieve 'balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases'. This statement on 'greenhouse gas balance' is subject to interpretation, and clarifications are needed to make it operational for national and international climate policies. We study possible interpretations from a scientific perspective and analyse their climatic implications. We clarify how the implications for individual gases depend on the metrics used to relate them. We show that the way in which balance is interpreted, achieved and maintained influences temperature outcomes. Achieving and maintaining net-zero CO2-equivalent emissions conventionally calculated using GWP100 (100-year global warming potential) and including substantial positive contributions from short-lived climate-forcing agents such as methane would result in a sustained decline in global temperature. A modified approach to the use of GWP100 (that equates constant emissions of short-lived climate forcers with zero sustained emission of CO2) results in global temperatures remaining approximately constant once net-zero CO2-equivalent emissions are achieved and maintained. Our paper provides policymakers with an overview of issues and choices that are important to determine which approach is most appropriate in the context of the Paris Agreement.This article is part of the theme issue 'The Paris Agreement: understanding the physical and social challenges for a warming world of 1.5°C above pre-industrial levels'.

Effect of gonadotropin-inhibitory hormone on luteinizing hormone secretion in humans.

BACKGROUND: Gonadotropin-inhibitory hormone (GnIH, human homologue of RFRP-3) suppresses gonadotropin secretion in animal models, but its effects have not been studied in the human. OBJECTIVE: We tested the hypotheses that exogenous GnIH inhibits LH secretion (i) in postmenopausal women and (ii) in men concurrently administered exogenous kisspeptin. DESIGN: Following in vitro and in vivo preclinical studies to functionally characterize the GnIH peptide, a dose-finding study (human GnIH: 1·5-150 µg/kg/h, iv for 3 h) was undertaken, and 50 µg/kg/h selected for further evaluation. Five postmenopausal women were administered 50 µg/kg/h iv infusion for 3 h or vehicle on two separate days. Four men were administered kisspeptin-10 (0·3 µg/kg iv bolus) with simultaneous infusion of GnIH (50 µg/kg/h, iv for 3 h) or vehicle. PARTICIPANTS: Healthy postmenopausal women (mean age 58 ± 2 years, LH: 30·8 ± 2·9 IU/l, FSH: 78·7 ± 6·4 IU/l, oestradiol: <50 pmol/l) and men (39·8 ± 2·1 years, mean total testosterone 12·1 ± 1·8 nmol/l, LH 2·2 ± 0·2 IU/l). PRIMARY OUTCOME: Change in area under curve (AUC) of LH during GnIHvs vehicle. RESULTS: During GnIH administration in postmenopausal women, LH secretion decreased (ΔAUC: -9·9 ± 1·8 IU/3 h) vs vehicle (ΔAUC: -0·5 ± 1·7 IU/3 h; P = 0·02). Kisspeptin-10-stimulated LH responses in men were not affected by GnIH co-administration (60-min AUC of LH 6·2 ± 0·8 IU/h with kisspeptin-10 alone, 6·3 ± 1·0 IU/h, kisspeptin-10 with GnIH, P = 0·72). Exogenous GnIH was well tolerated, with no adverse events reported. CONCLUSIONS: Gonadotropin-inhibitory hormone decreased LH secretion in postmenopausal women in this first-in-human study. Kisspeptin-stimulated LH secretion in men was not inhibited during concomitant administration of GnIH.

Mid-infrared light emission > 3 µm wavelength from tensile strained GeSn microdisks.

GeSn alloys with Sn contents of 8.4 % and 10.7 % are grown pseudomorphically on Ge buffers on Si (001) substrates. The alloys as-grown are compressively strained, and therefore indirect bandgap. Undercut GeSn on Ge microdisk structures are fabricated and strained by silicon nitride stressor layers, which leads to tensile strain in the alloys, and direct bandgap photoluminescence in the 3-5 µm gas sensing window of the electromagnetic spectrum. The use of pseudomorphic layers and external stress mitigates the need for plastic deformation to obtain direct bandgap alloys. It is demonstrated, that the optically pumped light emission overlaps with the methane absorption lines, suggesting that GeSn alloys are well suited for mid-infrared integrated gas sensors on Si chips.

Sublethal effects of angling and release on golden perch Macquaria ambigua: implications for reproduction and fish health.

The present study tested the hypothesis of no delayed sublethal effects of mild angling and release on the feeding, growth, somatic condition and gonadal development of golden perch Macquaria ambigua during gametogenesis. Subsamples of adult M. ambigua (n = 17-21 of 207), originally captured from the wild and stocked into ten 0·1 ha earthen ponds, were angled and released during early and late gametogenesis. Wild samples that were concurrently collected throughout the experiment underwent rapid and synchronous gonadal development and many spawned. While no spawning occurred in the ponds, most M. ambigua underwent normal gonadal development to maturity, including the angled fish. Angled fish also fed, maintained condition and actually grew faster than non-angled captive controls. Although females that were angled during late gametogenesis more readily ingested and retained baited hooks, neither their subsequent condition nor gonadal development was significantly affected. The predominance of null results was attributed to the combined effects of the flexible reproductive strategy of M. ambigua, the benignness of mouth hooking and immediate release, and possible methodological issues arising from differential hooking success of more aggressive and resilient individuals. The findings support earlier catch-and-release research, but contrast with reports of acute reproductive effects following capture and handling for aquaculture broodstock. This discrepancy highlights the need for research to specifically address welfare questions relevant to recreational fisheries across various species and angling scenarios.

Analysis of Ge micro-cavities with in-plane tensile strains above 2.

Ge on Si micro-disk, ring and racetrack cavities are fabricated and strained using silicon nitride stressor layers. Photoluminescence measurements demonstrate emission at wavelengths ≥ 2.3 µm, and the highest strained samples demonstrate in-plane, tensile strains of > 2 %, as measured by Raman spectroscopy. Strain analysis of the micro-disk structures demonstrate that shear strains are present in circular cavities, which can detrimentally effect the carrier concentration for direct band transitions. The advantages and disadvantages of each type of proposed cavity structure are discussed.

Mapping the spatio-temporal distribution of threatened batoids to improve conservation in a subtropical estuary.

The spatio-temporal distributions of four batoid species were examined in a subtropical estuary. Fluvial gradient was the most important factor explaining abundances, reflecting positive relationships with either salinity or distance from urbanised areas that were consistent across seasons and depths. The results support existing protected areas.

Extending the emission wavelength of Ge nanopillars to 2.25 µm using silicon nitride stressors.

The room temperature photoluminescence from Ge nanopillars has been extended from 1.6 µm to above 2.25 µm wavelength through the application of tensile stress from silicon nitride stressors deposited by inductively-coupled-plasma plasma-enhanced chemical-vapour-deposition. Photoluminescence measurements demonstrate biaxial equivalent tensile strains of up to ∼ 1.35% in square topped nanopillars with side lengths of 200 nm. Biaxial equivalent strains of 0.9% are observed in 300 nm square top pillars, confirmed by confocal Raman spectroscopy. Finite element modelling demonstrates that an all-around stressor layer is preferable to a top only stressor, as it increases the hydrostatic component of the strain, leading to an increased shift in the band-edge and improved uniformity over top-surface only stressors layers.

Helminth parasites in the endangered Ethiopian wolf, Canis simensis.

Ethiopian wolves, Canis simensis, are an endangered carnivore endemic to the Ethiopian highlands. Although previous studies have focused on aspects of Ethiopian wolf biology, including diet, territoriality, reproduction and infectious diseases such as rabies, little is known of their helminth parasites. In the current study, faecal samples were collected from 94 wild Ethiopian wolves in the Bale Mountains of southern Ethiopia, between August 2008 and February 2010, and were screened for the presence of helminth eggs using a semi-quantitative volumetric dilution method with microscopy. We found that 66 of the 94 faecal samples (70.2%) contained eggs from at least one group of helminths, including Capillaria, Toxocara, Trichuris, ancylostomatids, Hymenolepis and taeniids. Eggs of Capillaria sp. were found most commonly, followed by Trichuris sp., ancylostomatid species and Toxocara species. Three samples contained Hymenolepis sp. eggs, which were likely artefacts from ingested prey species. Four samples contained taeniid eggs, one of which was copro-polymerase chain reaction (copro-PCR) and sequence positive for Echinococcus granulosus, suggesting a spillover from a domestic parasite cycle into this wildlife species. Associations between presence/absence of Capillaria, Toxocara and Trichuris eggs were found; and egg burdens of Toxocara and ancylostomatids were found to be associated with geographical location and sampling season.

ABO incompatible renal transplantation without antibody removal using conventional immunosuppression alone.

ABO incompatible living donor renal transplantation (ABOi) can achieve outcomes comparable to ABO compatible transplantation (ABOc). However, with the exception of blood group A2 kidneys transplanted into recipients with low titer anti-A antibody, regimens generally include antibody removal, intensified immunosuppression and splenectomy or rituximab. We now report a series of 20 successful renal transplants across a range of blood group incompatibilities using conventional immunosuppression alone in recipients with low baseline anti-blood group antibody (ABGAb) titers. Incompatibilities were A1 to O (3), A1 to B (2), A2 to O (2), AB to A (2), AB to B (1), B to A1 (9), B to O (1); titers 1:1 to 1:16 by Ortho. At 36 months, patient and graft survival are 100%. Antibody-mediated rejection (AbMR) occurred in one patient with thrombophilia and low level donor-specific anti-HLA antibody. Four patients experienced cellular rejection (two subclinical), which responded to oral prednisolone. This series demonstrates that selected patients with low titer ABGAb can undergo ABOi with standard immunosuppression alone, suggesting baseline titer as a reliable predictor of AbMR. This reduces morbidity and cost of ABOi for patients with low titer ABGAb and increases the possibility of ABOi from deceased donors.

The role of neurokinin B signalling in reproductive neuroendocrinology.

The KNDy neuropeptides, kisspeptin, neurokinin B (NKB) and dynorphin A (Dyn), have been implicated in regulating pulsatile luteinising hormone (LH) secretion. Studies of the interactions between KNDy signalling systems, however, are currently few. Although the stimulatory effect of kisspeptin and the inhibitory effect of Dyn on the gonadotropin-releasing hormone pulse generator are widely accepted, the effects of NKB in rodents are variable and sometimes controversial. Literature describing increased LH secretion in response to NKB receptor agonism predominates and is in line with human physiology, as well as the pathophysiology of pubertal failure associated with disruption of NKB signalling. However, the robust suppression of the LH pulse, induced by the same treatment under hypoestrogenic conditions, may hold clues as to the mechanisms of reproductive inhibition under pathological conditions. This review discusses the recent evidence for this paradox and outlines a revised working model incorporating the mechanisms by which KNDy neuropeptides modulate the reproductive axis.

A one-step-ahead pseudo-DIC for comparison of Bayesian state-space models.

In the context of state-space modeling, conventional usage of the deviance information criterion (DIC) evaluates the ability of the model to predict an observation at time t given the underlying state at time t. Motivated by the failure of conventional DIC to clearly choose between competing multivariate nonlinear Bayesian state-space models for coho salmon population dynamics, and the computational challenge of alternatives, this work proposes a one-step-ahead DIC, DICp, where prediction is conditional on the state at the previous time point. Simulations revealed that DICp worked well for choosing between state-space models with different process or observation equations. In contrast, conventional DIC could be grossly misleading, with a strong preference for the wrong model. This can be explained by its failure to account for inflated estimates of process error arising from the model mis-specification. DICp is not based on a true conditional likelihood, but is shown to have interpretation as a pseudo-DIC in which the compensatory behavior of the inflated process errors is eliminated. It can be easily calculated using the DIC monitors within popular BUGS software when the process and observation equations are conjugate. The improved performance of DICp is demonstrated by application to the multi-stage modeling of coho salmon abundance in Lobster Creek, Oregon.

The curious case of the hypothalamic-pituitary-gonadal axis dysfunction in subordinate female naked mole-rats (Heterocephalus glaber): No apparent role of opioids and glucocorticoids.

The naked mole-rat (Heterocephalus glaber) is a unique model mammal in which to study socially induced inhibition of the hypothalamic-pituitary-gonadal (HPG) axis. Naked mole-rat groups exhibit a high degree of reproductive bias in which breeding is restricted to one female (the queen) and one male, with subordinate non-breeding colony members rarely, if ever, having the opportunity to reproduce due to a dysfunctional HPG axis. It is posited that aggression directed at subordinates by the queen suppresses reproduction in these subordinates, yet the underlying physiological mechanisms causing this dysfunction are unknown. This study aimed to investigate the possible factors contributing to the dysfunction of the HPG axis in subordinate female naked mole-rats with a specific focus on the role of ovarian feedback and stress-related factors such as circulating glucocorticoid and endogenous opioid peptides. The results showed that stress-related factors appear to not mediate the suppression of reproductive function in subordinate female naked mole rats. Indeed, in some cases, the activation of the stress axis may lead to reproductive activation instead of deactivation. At the same time, the role of ovarian sex steroid feedback in reproductive suppression is likely limited and not clearly delineated. This study highlights the need for detailed studies to elucidate the mechanism of reproductive suppression in this unique model mammalian species which may shed light on, and reveal novel mechanisms, in the social regulation of reproduction.

Kisspeptin-10 stimulation of gonadotrophin secretion in women is modulated by sex steroid feedback.

STUDY QUESTION: Does sex-steroid feedback influence gonadotrophin responses to kisspeptin-10? SUMMARY ANSWER: Gonadotrophin response to kisspeptin-10 is enhanced in sex-steroid deficient post-menopausal women and suppressed in women taking pharmacological doses of exogenous estrogen and progestogen. WHAT IS KNOWN ALREADY: Kisspeptin, a novel hypothalamic neuropeptide, stimulates gonadotrophin secretion by stimulating GnRH secretion and has been shown in animal models to play a pivotal role in mediating sex steroid feedback. As estrogen feedback occurs at both the hypothalamus and the pituitary levels, we hypothesized that the stimulatory effect of kisspeptin-10 in women would be dependent on prevailing sex steroid milieu. STUDY DESIGN, SIZE, DURATION: An experimental study of a novel neuropeptide in women-10 in the early follicular phase, 6 post-menopausal and 8 taking sex-steroid contraceptives (combined pill, n = 4; progestogen implants, n = 4) with suppressed LH secretion. Gonadotrophin secretion was followed for 60 min after kisspeptin administration. METHODS AND PARTICIPANTS: The gonadotrophin response to intravenous kisspeptin-10 (0.3 µg/kg) in women in the early follicular phase was compared with that in the presence of low endogenous sex steroids/high gonadotrophin secretion (post-menopausal women) and in women taking sex-steroid contraceptives (combined pill, n = 4; progestogen implants, n = 4) with suppressed LH secretion. Area under the curve (AUC) of gonadotrophin secretion sampled at 15 min intervals over 60 min before and after kisspeptin-10 was analysed. MAIN RESULTS AND ROLE OF CHANCE: Kisspeptin-10 stimulated LH secretion in follicular (ΔAUC 2.3 ± 0.8 IU/l h, P = 0.009), post-menopausal (5.3 ± 0.9 IU/l h P 0.002) and progestogen (2.6 ± 0.8 IU/l h P 0.05) groups but not in women taking combined pill (0.9 ± 0.4 IU/l h P 0.13). FSH secretion was significantly increased only in post-menopausal women (ΔAUC 2.6 ± 0.8 IU/l h P = 0.03) with changes of <0.5 IU/l h observed in the other three groups. Both LH and FSH responses in post-menopausal women were significantly larger than the other groups (one-way ANOVA analysis of ΔAUC; LH (P = 0.012) and FSH (P = 0.001)]. LIMITATIONS, REASONS FOR CAUTION: This study only assessed acute responses to an intravenous bolus of kisspeptin-10 administration, and the impact of continuous exposure to kisspeptin-10 on LH pulse frequency in women remains to be studied to fully understand the translational potential. WIDER IMPLICATIONS OF THE FINDINGS: Gonadotrophin secretion in women is stimulated by kisspeptin-10. These results suggest that the pituitary gonadotrope is a functionally important locus of estrogen feedback in women and also inform potential translational applications of kisspeptin in reproductive endocrine disorders. STUDY FUNDING: Medical Research Council (UK). COMPETING INTERESTS: None.

Contrast imaging ultrasound detects abnormalities in the marmoset ovary.

The development of a functional vascular tree within the primate ovary is critical for reproductive health. To determine the efficacy of contrast agents to image the microvascular environment within the primate ovary, contrast ultrasonography was performed in six reproductive-aged female common marmosets (Callithrix jacchus) during the late luteal phase of the cycle, following injection of Sonovue™. Regions of interest (ROIs), representing the corpus luteum (CL) and noncorpus luteum ovarian tissue (NCLOT), were selected during gray-scale B-mode ultrasound imaging. The magnitude of backscatter intensity of CL and NCLOT ROIs were calculated in XnView, post hoc: subsequent gamma-variate modeling was implemented in Matlab to determine perfusion parameters. Histological analysis of these ovaries revealed a total of 11 CL, nine of which were identified during contrast ultrasonography. The median enhancement ratio was significantly increased in the CL (5.54AU; 95% CI -2.21-68.71) compared to the NCLOT (2.82AU; 95% CI 2.73-15.06; P < 0.05). There was no difference in time parameters between the CL and NCLOT. An additional avascular ROI was identified in the ovary of Animal 5, both histologically and by ultrasonography. This cystic ROI displayed a markedly lower enhancement ratio (0.79AU) and higher time parameters than mean CL and NCLOT, including time to peak and time to wash out. These data demonstrate, for the first time, the ability of commercially available contrast agents, to differentiate structures within the nonhuman primate ovary. Contrast-enhanced ultrasonography has a promising future in reproductive medicine.

Profile and management of acute coronary syndromes at primary- and secondary-level healthcare facilities in Cape Town.

BACKGROUND: Little is known about the clinical profile and management of patients with acute coronary syndromes (ACS) in the South African public sector. METHODS: We conducted a retrospective study of patients presenting with ACS to a secondary-level healthcare facility in Cape Town during a one-year period to study the clinical profile and management of these patients. RESULTS: Among the 214 patients in this cohort, 48 (27.5%) had ST-segment elevation myocardial infarction (STEMI), 43 (24.7%) had non-ST-segment elevation myocardial infarction and 83 (47.7%) unstable angina pectoris. We identified high rates of >12-hour delays in first medical contact after symptom onset (46%) and inaccurate ECG diagnosis of STEMI (29.2%), which were associated with low rates of thrombolysis (39.6%). High rates of non-adherence and ACS recurrence were also observed. CONCLUSION: To address the local challenges in ACS management highlighted in this study, we propose the development of a regional referral network prioritising access to expedited care and primary reperfusion interventions in ACS.

Successful ABO-incompatible kidney transplantation with antibody removal and standard immunosuppression.

ABO-incompatible (ABOi) kidney transplantation is an established therapy, though its implementation to date has been in part limited by the requirement for additional immunosuppression. Here, we describe the outcomes of 37 patients undergoing ABOi kidney transplantation utilizing perioperative antibody depletion and receiving an identical tacrolimus-based immunosuppressive regimen to contemporaneous ABO-compatible (ABOc) recipients, with the exception that mycophenolate was commenced earlier (7-14 days pretransplant). Antibody depletion was scheduled according to baseline anti-ABO antibody titer (tube IAT method: median 1:128, range 1:8 to 1:4096). Patient and graft survival for the 37 ABOi recipients was 100% after a median 26 months (interquartile range [IQR] 18-32). Eight rejection episodes (two antibody-mediated and six cellular) in ABOi recipients were successfully treated with biopsy-proven resolution. Latest median eGFR is 50 mL/min × 1.73 m² (IQR 40-64) for ABOi patients and 54 mL/min × 1.73 m² (IQR 44-66) in the ABOc patients (p = 0.25). We conclude that ABOi transplantation can be performed successfully with perioperative antibody removal and conventional immunosuppression. This suggests that access to ABOi transplantation can include a broader range of end-stage kidney disease patients.

Heterogeneity of vertebrate luteinizing hormone-releasing hormone.

Radioimmunoassay and chromatography analyses of hypothalamic luteinizing hormone-releasing hormone (LHRH) have demonstrated the presence of LHRH-like immunoreactive peptides in a wide range of vertebrates. Contrary to previous reports, the molecule differs in various vertebrates. Avian, reptilian, and teleostean LHRH's are chemically distinct from the mammalian peptide but are in themselves indistinguishable. However, amphibian LHRH appears to be identical to the mammalian peptide. These findings have interesting evolutionary implications.