Statistical properties of hybrid estimators proposed for GEDI – NASA’s Global Ecosystem Dynamics Investigation

NASA’s Global Ecosystem Dynamics Investigation (GEDI) mission will collect waveform lidar data at a dense sample of ∼25 m footprints along ground tracks paralleling the orbit of the International Space Station (ISS). GEDI’s primary science deliverable will be a 1 km grid of estimated mean aboveground biomass density (Mg ha ^−1 ), covering the latitudes overflown by ISS (51.6 °S to 51.6 °N). One option for using the sample of waveforms contained within an individual grid cell to produce an estimate for that cell is hybrid inference, which explicitly incorporates both sampling design and model parameter covariance into estimates of variance around the population mean. We explored statistical properties of hybrid estimators applied in the context of GEDI, using simulations calibrated with lidar and field data from six diverse sites across the United States. We found hybrid estimators of mean biomass to be unbiased and the corresponding estimators of variance appeared to be asymptotically unbiased, with under-estimation of variance by approximately 20% when data from only two clusters (footprint tracks) were available. In our study areas, sampling error contributed more to overall estimates of variance than variability due to the model, and it was the design-based component of the variance that was the source of the variance estimator bias at small sample sizes. These results highlight the importance of maximizing GEDI’s sample size in making precise biomass estimates. Given a set of assumptions discussed here, hybrid inference provides a viable framework for estimating biomass at the scale of a 1 km grid cell while formally accounting for both variability due to the model and sampling error

Globalisation masculinities, empire building and forced prostitution: a critical analysis of the gendered impact of the neoliberal economic agenda in post-invasion/occupation Iraq

Adopting a transnational feminist lens and using a political economy approach, this article addresses both the direct and indirect consequences of the 2003 war in Iraq, specifically the impact on civilian women. Pre-war security and gender relations in Iraq will be compared with the situation post-invasion/occupation. The article examines the globalised processes of capitalism, neoliberalism and neo-colonialism and their impact on the political, social and economic infrastructure in Iraq. Particular attention will be paid to illicit and informal economies: coping, combat and criminal. The 2003 Iraq war was fought using masculinities of empire, post-colonialism and neoliberalism. Using the example of forced prostitution, the article will argue that these globalisation masculinities – specifically the privatisation agenda of the West and its illegal economic occupation – have resulted in women either being forced into the illicit (coping) economy as a means of survival, or trafficked for sexual slavery by profit-seeking criminal networks who exploit the informal economy in a post-invasion/occupation Iraq

Update of the best practice dietetic management of overweight and obese children and adolescents: a systematic review protocol

To update an existing systematic review series of randomized controlled trials (RCT) that include a dietary intervention for the management of overweight or obesity in children or adolescents.Specifically, the review questions are: In randomized controlled trials of interventions which include a dietary intervention for the management of overweight or obesity in children or adolescents

The Global Ecosystem Dynamics Investigation: High-resolution laser ranging of the Earth’s forests and topography

Obtaining accurate and widespread measurements of the vertical structure of the Earths forests has been a longsought goal for the ecological community. Such observations are critical for accurately assessing the existing biomass of forests, and how changes in this biomass caused by human activities or variations in climate may impact atmospheric CO2 concentrations. Additionally, the three-dimensional structure of forests is a key component of habitat quality and biodiversity at local to regional scales. The Global Ecosystem Dynamics Investigation (GEDI) was launched to the International Space Station in late 2018 to provide high-quality measurements of forest vertical structure in temperate and tropical forests between 51.6 N & S latitude. The GEDI instrument is a geodetic-class laser altimeter/waveform lidar comprised of 3 lasers that produce 8 transects of structural information. Over its two-year nominal lifetime GEDI is anticipated to provide over 10 billion waveforms at a footprint resolution of 25 m. These data will be used to derive a variety of footprint and gridded products, including canopy height, canopy foliar profiles, Leaf Area Index (LAI), sub-canopy topography and biomass. Additionally, data from GEDI are used to demonstrate the efficacy of its measurements for prognostic ecosystem modeling, habit and biodiversity studies, and for fusion using radar and other remote sensing instruments. GEDI science and technology are unique: no other space-based mission has been created that is specifically optimized for retrieving vegetation vertical structure. As such, GEDI promises to advance our understanding of the importance of canopy vertical variations within an ecological paradigm based on structure, composition and function

GEDI launches a new era of biomass inference from space

Accurate estimation of aboveground forest biomass stocks is required to assess the impacts of land use changes such as deforestation and subsequent regrowth on concentrations of atmospheric CO2. The Global Ecosystem Dynamics Investigation (GEDI) is a lidar mission launched by NASA to the International Space Station in 2018. GEDI was specifically designed to retrieve vegetation structure within a novel, theoretical sampling design that explicitly quantifies biomass and its uncertainty across a variety of spatial scales. In this paper we provide the estimates of pan-tropical and temperate biomass derived from two years of GEDI observations. We present estimates of mean biomass densities at 1 km resolution, as well as estimates aggregated to the national level for every country GEDI observes, and at the sub-national level for the United States. For all estimates we provide the standard error of the mean biomass. These data serve as a baseline for current biomass stocks and their future changes, and the mission's integrated use of formal statistical inference points the way towards the possibility of a new generation of powerful monitoring tools from space

The correlation between reading and mathematics ability at age twelve has a substantial genetic component

Dissecting how genetic and environmental influences impact on learning is helpful for maximizing numeracy and literacy. Here we show, using twin and genome-wide analysis, that there is a substantial genetic component to children’s ability in reading and mathematics, and estimate that around one half of the observed correlation in these traits is due to shared genetic effects (so-called Generalist Genes). Thus, our results highlight the potential role of the learning environment in contributing to differences in a child’s cognitive abilities at age twelve

Impact of weight management nutrition interventions on dietary outcomes in children and adolescents with overweight or obesity: A systematic review with meta-analysis

Background The impact of obesity interventions on dietary intake in children and adolescents with overweight or obesity is unclear. This systematic review aimed to investigate the impact of the dietary component of weight management interventions on the change in diet in children and adolescents with overweight or obesity. Methods Eligible RCTs published between 1975 and 2020 were identified by a systematic search following PRISMA guidelines. Meta-analyses of eligible study outcomes was performed using R statistical software. A multi-level random effects model was used with three significant random effects fitted using Restricted Maximum Likelihood estimation. Results This review identified 109 RCTs, including 95 that reported at least one statistically significant dietary outcome change, and 14 reporting no significant dietary change. Results from the meta-analyses (n= 29 studies) indicated that compared to control groups, intervention groups achieved significantly greater reductions in mean total energy intake at ≤6 months (-194kcal/day, 95%CI -275.80 to -112.90kcal/day, p<0.001) and up to 12 months (-112k cal/ day 95% CI -218.92 to -5.83kcal/ day)p=0.038), increases in fruit and/or vegetable intakes over 2-12 months (n=34, range +0.6 to +1.5 servings/day) and reductions in consumption of sugar-sweetened beverages (n=28, range -0.25 to -1.5 servings/day) at 4-24 months follow-up. Conclusions Obesity interventions with a dietary component have a modest, but sustained impact on reducing total energy intake and improving intakes of specific food groups in children and adolescents with overweight or obesity. High quality RCTs that are powered to detect change in diet as a primary outcome are warranted

The Importance of Consistent Global Forest Aboveground Biomass Product Validation

Several upcoming satellite missions have core science requirements to produce data for accurate forest aboveground biomass mapping. Largely because of these mission datasets, the number of available biomass products is expected to greatly increase over the coming decade. Despite the recognized importance of biomass mapping for a wide range of science, policy and management applications, there remains no community accepted standard for satellite-based biomass map validation. The Committee on Earth Observing Satellites (CEOS) is developing a protocol to fill this need in advance of the next generation of biomass-relevant satellites, and this paper presents a review of biomass validation practices from a CEOS perspective. We outline the wide range of anticipated user requirements for product accuracy assessment and provide recommendations for the validation of biomass products. These recommendations include the collection of new, high-quality in situ data and the use of airborne lidar biomass maps as tools toward transparent multi-resolution validation. Adoption of community-vetted validation standards and practices will facilitate the uptake of the next generation of biomass products

Genome-wide association study identifies a variant in HDAC9 associated with large vessel ischemic stroke

Genetic factors have been implicated in stroke risk but few replicated associations have been reported. We conducted a genome-wide association study (GWAS) in ischemic stroke and its subtypes in 3,548 cases and 5,972 controls, all of European ancestry. Replication of potential signals was performed in 5,859 cases and 6,281 controls. We replicated reported associations between variants close to PITX2 and ZFHX3 with cardioembolic stroke, and a 9p21 locus with large vessel stroke. We identified a novel association for a SNP within the histone deacetylase 9(HDAC9) gene on chromosome 7p21.1 which was associated with large vessel stroke including additional replication in a further 735 cases and 28583 controls (rs11984041, combined P = 1.87×10−11, OR=1.42 (95% CI) 1.28-1.57). All four loci exhibit evidence for heterogeneity of effect across the stroke subtypes, with some, and possibly all, affecting risk for only one subtype. This suggests differing genetic architectures for different stroke subtypes

Security (studies) and the limits of critique: why we should think through struggle

This paper addresses the political and epistemological stakes of knowledge production in post-structuralist Critical Security Studies. It opens a research agenda in which struggles against dominant regimes of power/knowledge are entry-points for analysis. Despite attempts to gain distance from the word ‘security’, through interrogation of wider practices and schemes of knowledge in which security practices are embedded, post-structuralist CSS too quickly reads security logics as determinative of modern/liberal forms of power and rule. At play is an unacknowledged ontological investment in ‘security’, structured by disciplinary commitments and policy discourse putatively critiqued. Through previous ethnographic research, we highlight how struggles over dispossession and oppression call the very frame of security into question, exposing violences inadmissible within that frame. Through the lens of security, the violence of wider strategies of containing and normalizing politics are rendered invisible, or a neutral backdrop against which security practices take place. Building on recent debates on critical security methods, we set out an agenda where struggle provokes an alternative mode of onto political investment in critical examination of power and order