Beach-face slope dataset for Australia

Sandy beaches are unique environments composed of unconsolidated sediments that are constantly reshaped by the action of waves, tides, currents, and winds. The most seaward region of the dry beach, referred to as the beach face, is the primary interface between land and ocean and is of fundamental importance to coastal processes, including the dissipation and reflection of wave energy at the coast, and the exchange of sediment between the land and sea. The slope of the beach-face is a critical parameter in coastal geomorphology and coastal engineering, necessary to calculate the total elevation and excursion of wave run-up at the shoreline. However, datasets of the beach-face slope remain unavailable along most of the world’s coastlines. This study presents a new dataset of beach-face slopes for the Australian coastline derived from a novel remote sensing technique. The dataset covers 13,200 km of sandy coast and provides an estimate of the beach-face slope at every 100 m alongshore, accompanied by an easy to apply measure of the confidence of each slope estimate. The dataset offers a unique view of large-scale spatial variability in beach-face slope and addresses the growing need for this information to predict coastal hazards around Australia. The beach-face slope dataset and relevant metadata are available at https://doi.org/10.5281/zenodo.5606217 (Vos et al., 2021)

MO256THE TREATMENT EFFECT OF RAS BLOCKADE ON PROTEINURIA IN IGA NEPHROPATHY PATIENTS AS A SURROGATE FOR RENAL EVENTS AND DECLINE IN EGFR: AN ANALYSIS OF RANDOMIZED CONTROLLED TRIALS

Background and Aims Renin-Angiotensin System Blockade (RASB) is the cornerstone of standard-of-care in IgA nephropathy. Randomized controlled trials (RCTs) have shown the treatment benefit of RASB therapy on proteinuria and risk of renal failure. The objective of this study was to describe the relationships between the treatment effect of RASB on proteinuria and (i) risk of renal events, and (ii) decline in eGFR, as an endpoint proximal to renal failure. To this aim, trial level (TL) and simple weighted linear regression (SWR) analyses were conducted on RCTs identified through a systematic literature review, with RASB as the active intervention. Methods A systematic literature review of available peer-reviewed literature from 1990 to 2020 was performed applying the following inclusion criteria: RCT in patients with biopsy-proven IgAN, investigating the effects of RASB as an intervention, sample size >25, measurement of proteinuria at baseline and at >3 months. At least 1 renal event (defined as ≥50% decline in eGFR, CKD Stage 5, dialysis or transplantation) was required for the renal event analysis and similarly, at least 12 months follow-up was required for the decline in eGFR analysis. For the relationship between proteinuria and risk of renal events, 4 studies including 5 comparisons were identified, while 9 studies including 10 comparisons were identified for the analysis of proteinuria vs eGFR decline. Proteinuria change from baseline was calculated from the value closest to 6 months. If annualized change in eGFR was reported, these data were used, otherwise annualized change in eGFR was calculated per year of follow-up. Methods as described by Burzykoski & Buyse (2006) and Joffe & Greene (2008) were used for TL meta-regression analyses; the resulting meta-regression line was displayed with an 80% credible interval band (CB). Given the assumptions made in this analysis, a SWR analysis was also performed; to compensate for potential underestimation of error associated with the regression line, a 99.9% CB was applied in the SWR analysis. Results For RASB treatment effects on renal events, a statistical association was found with treatment effects on proteinuria with a TL slope estimate = 15.30 95% CI (0.57, 38.79), R2 = 0.88 95% CI (0.22, 1.00); using the lower CI of 0.75 for the estimated slope, a 30% treatment effect on proteinuria would be expected to result in at least a 25% reduction in the risk of renal events. As individual subject level data were not available, the correlation between errors on treatment effects for proteinuria and treatment effects for renal events were unknown, resulting in a wide CB on the meta-regression line and a wide CI for the slope estimate. The SWR approach is not hampered by lack of subject level data and gave a slope estimate of 3.5 95% CI (2.1, 5.0) with R2 = 0.97, such that a 30% treatment effect on proteinuria would be expected to result in at least a 64% reduction in the risk of renal events. For treatment effects on annualized eGFR versus effects on proteinuria, the TL slope estimate was -5.1 95% CI (-30.2, 35.0), R2 = 0.89 95% CI (0.15, 1.00); the corresponding SWR slope estimate was -7.6, 95% CI (-12.3, -2.8) with R2 = 0.71. A 30% treatment effect on proteinuria would be expected to result in a 2.6 mL/min (TL analysis) to 3.9 mL/min slower decline (SWR analysis) in annualized eGFR. Conclusion In patients with IgAN, associations were seen between treatment effects of RASB on proteinuria and on the clinically relevant endpoints of renal events and annualized change in eGFR. Consistent with TL analyses of RCTs across a variety of mechanisms of actions, these data, specific to RASB, contribute to the growing evidence base supporting the use of proteinuria as a valid surrogate endpoint in IgAN.

Improved method of estimating temperatures at meteor peak heights

For two decades meteor radars have been routinely used to monitor temperatures around the 90 km altitude. A common method, based on a temperature-gradient model, is to use the height dependence of meteor decay time to obtain a height-averaged temperature in the peak meteor region. Traditionally this is done by fitting a linear regression model in the scattered plot of log10(1 / τ) and height, where τ is the half-amplitude decay time of the received signal. However, this method was found to be consistently biasing the slope estimate. The consequence of such bias is that it produces a systematic offset in the estimated temperature, and thus requiring calibration with other colocated measurements. The main reason for such a biasing effect is thought to be due to the failure of the classical regression model to take into account the measurement error in τ or the observed height. This is further complicated by the presence of various geophysical effects in the data, which are not taken into account in the physical model. The effect of such biasing is discussed on both theoretical and experimental grounds. An alternative regression method that incorporates various error terms in the statistical model is used for line fitting. This model is used to construct an analytic solution for the bias-corrected slope coefficient for this data. With this solution, meteor radar temperatures can be obtained independently without using any external calibration procedure. When compared with colocated lidar measurements, the temperature estimated using this method is found to be accurate within 7 % or better and without any systematic offset.

Extreme rainfall trends over the Mekong Delta under the impacts of climate change

Purpose This study aims to investigate aspects related to the changing trends of the rainfall extremes in the entire Mekong Delta in the period of 32 years (1984-2015) applying rainfall extreme indices. First, the homogeneity tests were applied to assess the quality of observed rainfall data series. The authors, then, investigated three rainfall indices including the number of very heavy rainfall days 20 mm (R20), number of days above 50 mm (R50) and number of days above 100 mm (R100) applying the Mann-Kendall test and Sen’s slope estimate. Design/methodology/approach First, the homogeneity tests were applied to assess the quality of observed rainfall data series. The authors, then, investigated three rainfall indices including the number of very heavy rainfall days 20 mm (R20), number of days above 50 mm (R50) and number of days above 100 mm (R100) applying the Mann-Kendall test and Sen’s slope estimate. Findings The results of R20 pointed out that an insignificant upward tendency was found in the coastal provinces, whereas an insignificant downward tendency was also recorded in the inland provinces. Regarding the number of R50, a similar trend to R20 was recorded with five stations slightly increased and five stations slightly decreased. For the number of R100, the results recorded an absence of significant trends over the entire study area. Approximately 58.5% of stations show a slightly decreasing trend, while 41.5% of the remaining stations recorded a slightly increasing trend. Originality/value For the number of R100, the results recorded an absence of the significant trends over the entire study area. Approximately 58.5% of stations show a slightly decreasing trend, while 41.5% of the remaining stations recorded a slightly increasing trend. Of note is the fact that the number of R100 occurred more frequently in the northern provinces, which means the northern region is facing a high risk of flooding.

Migraine is associated with high brain 5-HT levels as indexed by 5-HT4 receptor binding

Introduction Serotonin (5-HT) plays a role in migraine pathophysiology, but whether brain 5-HT is involved in the conversion from episodic to chronic migraine is unknown. Here, we investigated brain 5-HT levels, as indexed by 5-HT4 receptor binding, in chronic migraine patients and evaluated whether these were associated with migraine frequency. Methods Sixteen chronic migraine patients underwent a dynamic PET scan after injection of [11C]SB207145, a specific 5-HT4 receptor radioligand. Data from 15 episodic migraine patients and 16 controls were included for comparison. Quantification of 5-HT4 receptor binding was used as a proxy for brain 5-HT levels, since 5-HT4 receptor binding is inversely related to brain 5-HT levels. Results Chronic migraine patients had 9.1% (95% CI: [−17%; −1.0%]) lower 5-HT4 receptor binding compared to controls ( p = 0.039). There was no difference in 5-HT4 receptor binding between chronic and episodic migraine patients ( p = 0.48) and no association between number of monthly migraine days and 5-HT4 receptor binding (slope estimate 0.003, 95% CI: [−0.004; 0.715], p = 0.39). Conclusion The finding of low 5-HT4 receptor binding suggests that cerebral levels of 5-HT are elevated in chronic migraine patients. This is in line with observations made in patients with episodic migraine. Elevated brain 5-HT levels may thus be an inherent trait of the migraine brain rather than a risk factor for conversion from episodic to chronic migraine.

The multistep hypothesis of ALS revisited

ObjectiveAmyotrophic lateral sclerosis (ALS) incidence rates are consistent with the hypothesis that ALS is a multistep process. We tested the hypothesis that carrying a large effect mutation might account for ≥1 steps through the effect of the mutation, thus leaving fewer remaining steps before ALS begins.MethodsWe generated incidence data from an ALS population register in Italy (2007–2015) for which genetic analysis for C9orf72, SOD1, TARDBP, and FUS genes was performed in 82% of incident cases. As confirmation, we used data from ALS cases diagnosed in the Republic of Ireland (2006–2014). We regressed the log of age-specific incidence against the log of age with least-squares regression for the subpopulation carrying disease-associated variation in each separate gene.ResultsOf the 1,077 genetically tested cases, 74 (6.9%) carried C9orf72 mutations, 20 (1.9%) had SOD1 mutations, 15 (1.4%) had TARDBP mutations, and 3 (0.3%) carried FUS mutations. In the whole population, there was a linear relationship between log incidence and log age (r2 = 0.98) with a slope estimate of 4.65 (4.37–4.95), consistent with a 6-step process. The analysis for C9orf72-mutated patients confirmed a linear relationship (r2 = 0.94) with a slope estimate of 2.22 (1.74–2.29), suggesting a 3-step process. This estimate was confirmed by data from the Irish ALS register. The slope estimate was consistent with a 2-step process for SOD1 and with a 4-step process for TARDBP.ConclusionThe identification of a reduced number of steps in patients with ALS with genetic mutations compared to those without mutations supports the idea of ALS as a multistep process and is an important advance for dissecting the pathogenic process in ALS.