The generality of cryptic dietary niche differences in diverse large-herbivore assemblages.

Ecological niche differences are necessary for stable species coexistence but are often difficult to discern. Models of dietary niche differentiation in large mammalian herbivores invoke the quality, quantity, and spatiotemporal distribution of plant tissues and growth forms but are agnostic toward food plant species identity. Empirical support for these models is variable, suggesting that additional mechanisms of resource partitioning may be important in sustaining large-herbivore diversity in African savannas. We used DNA metabarcoding to conduct a taxonomically explicit analysis of large-herbivore diets across southeastern Africa, analyzing ∼4,000 fecal samples of 30 species from 10 sites in seven countries over 6 y. We detected 893 food plant taxa from 124 families, but just two families-grasses and legumes-accounted for the majority of herbivore diets. Nonetheless, herbivore species almost invariably partitioned food plant taxa; diet composition differed significantly in 97% of pairwise comparisons between sympatric species, and dissimilarity was pronounced even between the strictest grazers (grass eaters), strictest browsers (nongrass eaters), and closest relatives at each site. Niche differentiation was weakest in an ecosystem recovering from catastrophic defaunation, indicating that food plant partitioning is driven by species interactions, and was stronger at low rainfall, as expected if interspecific competition is a predominant driver. Diets differed more between browsers than grazers, which predictably shaped community organization: Grazer-dominated trophic networks had higher nestedness and lower modularity. That dietary differentiation is structured along taxonomic lines complements prior work on how herbivores partition plant parts and patches and suggests that common mechanisms govern herbivore coexistence and community assembly in savannas.

A revised action spectrum for vitamin D synthesis by suberythemal UV radiation exposure in humans in vivo.

Action spectra are important biological weighting functions for risk/benefit analyses of ultraviolet (UV) radiation (UVR) exposure. One important human benefit of exposure to terrestrial solar UVB radiation (∼295 to 315 nm) is the cutaneous synthesis of vitamin D3 that is initiated by the photoconversion of 7-dehydrocholesterol to previtamin D3 An action spectrum for this process that is followed by other nonphotochemical steps to achieve biologically active vitamin D3 has been established from ex vivo data and is widely used, although its validity has been questioned. We tested this action spectrum in vivo by full- or partial-body suberythemal irradiation of 75 healthy young volunteers with five different polychromatic UVR spectra on five serial occasions. Serum 25-hydroxyvitamin D3 [25(OH)D3] levels, as the most accurate measure of vitamin D3 status, were assessed before, during, and after the exposures. These were then used to generate linear dose-response curves that were different for each UVR spectrum. It was established that the previtamin D3 action spectrum was not valid when related to the serum 25(OH)D3 levels, as weighting the UVR doses with this action spectrum did not result in a common regression line unless it was adjusted by a blue shift, with 5 nm giving the best fit. Such a blue shift is in accord with the published in vitro action spectra for vitamin D3 synthesis. Thus, calculations regarding the risk (typically erythema) versus the benefit of exposure to solar UVR based on the ex vivo previtamin D3 action spectrum require revision.

Directional hydrophone clusters reveal evasive responses of small cetaceans to disturbance during construction at offshore windfarms.

Mitigation measures to disperse marine mammals prior to pile-driving include acoustic deterrent devices and piling soft starts, but their efficacy remains uncertain. We developed a self-contained portable hydrophone cluster to detect small cetacean movements from the distributions of bearings to detections. Using an array of clusters within 10 km of foundation pile installations, we tested the hypothesis that harbour porpoises (Phocoena phocoena) respond to mitigation measures at offshore windfarm sites by moving away. During baseline periods, porpoise movements were evenly distributed in all directions. By contrast, animals showed significant directional movement away from sound sources during acoustic deterrent device use and piling soft starts. We demonstrate that porpoises respond to measures aimed to mitigate the most severe impacts of construction at offshore windfarms by swimming directly away from these sound sources. Portable directional hydrophone clusters now provide opportunities to characterize responses to disturbance sources across a broad suite of habitats and contexts.

Can smaller predators expand their prey base through killing juveniles? The influence of prey demography and season on prey selection for cheetahs and lions.

Smaller predators may overcome body size restrictions on their prey base by selecting for juveniles of larger prey species. However, traditional prey selection models ignore demographic classes within prey species. We refined these models for two predators with contrasting body sizes and hunting strategies, by including seasonal consumption and availability of prey demographic classes. We predicted that cheetahs would select for smaller neonate and juvenile prey especially of larger species, while lions would select for larger, adult prey. We further predicted seasonal diet shifts in cheetah, but not lion. We recorded species-specific demographic class prey use (kills) via direct observation and GPS cluster of cheetahs and lions fitted with GPS collars. Species-specific demographic class prey availability was estimated from monthly driven transects, and species-specific demographic class prey preferences were estimated. The availability of prey demographic classes varied seasonally. Cheetahs preferred neonates, juveniles, and sub-adults during the wet season, but adults and juveniles during the dry season. Lions preferred adult prey irrespective of season, with sub-adults, juveniles, and neonates killed relative to their abundance. This confirms that traditional prey preference models do not adequately account for demographic-specific prey preference. This is particularly important for smaller predators, like cheetahs, that focus on smaller prey but can expand their prey base by killing juveniles of larger species. For these smaller predators, prey availability will vary strongly seasonally, making them more vulnerable to processes that influence prey reproduction, like global change.

Animal body size distribution influences the ratios of nutrients supplied to plants.

Nutrients released through herbivore feces have the potential to influence plant-available nutrients and affect primary productivity. However, herbivore species use nutrients in set stoichiometric ratios that vary with body size. Such differences in the ratios at which nutrients are used leads to differences in the ratios at which nutrients are deposited through feces. Thus, local environmental factors that affect the average body size of an herbivore community (such as predation risk and food availability) influence the ratios at which fecal nutrients are supplied to plants. Here, we assess the relationship between herbivore body size and the nitrogen-to-phosphorus ratios of herbivore feces. We examine how shifts in the average body size of an herbivore community alter the ratios at which nitrogen and phosphorus are supplied to plants and test whether such differences in the stoichiometry of nutrient supply propagate through plants. We show that dung from larger-bodied herbivores contain lower quantities of phosphorus per unit mass and were higher in N:P ratio. We demonstrate that spatial heterogeneity in visibility (a proxy for predation risk and/or food availability) and rainfall (a proxy for food availability), did not affect the overall amount of feces deposited but led to changes in the average body size of the defecating community. Feces deposited in areas of higher rainfall and reduced visibility originated from larger herbivores and were higher in N:P ratios. This indicates that processes that change the size distribution of herbivore communities, such as predation or size-biased extinction, have the potential to alter the nutrient landscape for plants.

Tools for assessing health research partnership outcomes and impacts: a systematic review.

OBJECTIVE: To identify and assess the globally available valid, reliable and acceptable tools for assessing health research partnership outcomes and impacts. METHODS: We searched Ovid MEDLINE, Embase, CINAHL Plus and PsycINFO from origin to 2 June 2021, without limits, using an a priori strategy and registered protocol. We screened citations independently and in duplicate, resolving discrepancies by consensus and retaining studies involving health research partnerships, the development, use and/or assessment of tools to evaluate partnership outcomes and impacts, and reporting empirical psychometric evidence. Study, tool, psychometric and pragmatic characteristics were abstracted using a hybrid approach, then synthesized using descriptive statistics and thematic analysis. Study quality was assessed using the quality of survey studies in psychology (Q-SSP) checklist. RESULTS: From 56 123 total citations, we screened 36 027 citations, assessed 2784 full-text papers, abstracted data from 48 studies and one companion report, and identified 58 tools. Most tools comprised surveys, questionnaires and scales. Studies used cross-sectional or mixed-method/embedded survey designs and employed quantitative and mixed methods. Both studies and tools were conceptually well grounded, focusing mainly on outcomes, then process, and less frequently on impact measurement. Multiple forms of empirical validity and reliability evidence was present for most tools; however, psychometric characteristics were inconsistently assessed and reported. We identified a subset of studies (22) and accompanying tools distinguished by their empirical psychometric, pragmatic and study quality characteristics. While our review demonstrated psychometric and pragmatic improvements over previous reviews, challenges related to health research partnership assessment and the nascency of partnership science persist. CONCLUSION: This systematic review identified multiple tools demonstrating empirical psychometric evidence, pragmatic strength and moderate study quality. Increased attention to psychometric and pragmatic requirements in tool development, testing and reporting is key to advancing health research partnership assessment and partnership science. PROSPERO CRD42021137932.

Building an integrated knowledge translation (IKT) evidence base: colloquium proceedings and research direction.

BACKGROUND: Integrated knowledge translation (IKT) is a model of research co-production, whereby researchers partner with knowledge users throughout the research process and who can use the research recommendations in practice or policy. IKT approaches are used to improve the relevance and impact of research. As an emerging field, however, the evidence underpinning IKT is in active development. The Integrated Knowledge Translation Research Network represents a collaborative interdisciplinary team that aims to advance the state of IKT science. METHODS: In 2017, the Integrated Knowledge Translation Research Network issued a call to its members for concept papers to further define IKT, outline an IKT research agenda, and inform the Integrated Knowledge Translation Research Network's special meeting entitled, Integrated Knowledge Translation State of the Science Colloquium, in Ottawa, Canada (2018). At the colloquium, authors presented concept papers and discussed knowledge-gaps for a research agenda and implications for advancing the IKT field. We took detailed field notes, audio-recorded the meeting and analysed the data using qualitative content analysis. RESULTS: Twenty-four participants attended the meeting, including researchers (n = 11), trainees (n = 6) and knowledge users (n = 7). Seven overarching categories emerged from these proceedings - IKT theory, IKT methods, IKT process, promoting partnership, definitions and distinctions of key IKT terms, capacity-building, and role of funders. Within these categories, priorities identified for future IKT research included: (1) improving clarity about research co-production/IKT theories and frameworks; (2) describing the process for engaging knowledge users; and (3) identifying research co-production/IKT outcomes and methods for evaluation. CONCLUSION: The Integrated Knowledge Translation State of the Science Colloquium initiated a research agenda to advance IKT science and practice. Next steps will focus on building a theoretical and evidence base for IKT.

A review of reviews on principles, strategies, outcomes and impacts of research partnerships approaches: a first step in synthesising the research partnership literature.

BACKGROUND: Conducting research in partnership with stakeholders (e.g. policy-makers, practitioners, organisations, patients) is a promising and popular approach to improving the implementation of research findings in policy and practice. This study aimed to identify the principles, strategies, outcomes and impacts reported in different types of reviews of research partnerships in order to obtain a better understanding of the scope of the research partnership literature. METHODS: This review of reviews is part of a Coordinated Multicenter Team approach to synthesise the research partnership literature with five conceptually linked literature reviews. The main research question was 'What principles, strategies, outcomes and impacts are reported in different types of research partnership approaches?'. We included articles describing a literature review of research partnerships using a systematic search strategy. We used an adapted version of the Revised Assessment of Multiple Systematic Reviews tool to assess quality. Nine electronic databases were searched from inception to April 2018. Principles, strategies, outcomes and impacts were extracted from the included reviews and analysed using direct content analysis. RESULTS: We included 86 reviews using terms describing several research partnership approaches (e.g. community-based participatory research, participatory research, integrated knowledge translation). After the analyses, we synthesised 17 overarching principles and 11 overarching strategies and grouped them into one of the following subcategories: relationship between partners; co-production of knowledge; meaningful stakeholder engagement; capacity-building, support and resources; communication process; and ethical issues related to the collaborative research activities. Similarly, we synthesised 20 overarching outcomes and impacts on researchers, stakeholders, the community or society, and the research process. CONCLUSIONS: This review of reviews is the first that presents overarching principles, strategies, outcomes and impacts of research partnerships. This review is unique in scope as we synthesised literature across multiple research areas, involving different stakeholder groups. Our findings can be used as a first step to guide the initiation and maintenance of research partnerships and to create a classification system of the key domains of research partnerships, which may improve reporting consistency in the research partnership literature. TRIAL REGISTRATION: This study is registered via Open Science Framework: https://doi.org/10.17605/OSF.IO/GVR7Y.

Deconstructing compassionate conservation.

Compassionate conservation focuses on 4 tenets: first, do no harm; individuals matter; inclusivity of individual animals; and peaceful coexistence between humans and animals. Recently, compassionate conservation has been promoted as an alternative to conventional conservation philosophy. We believe examples presented by compassionate conservationists are deliberately or arbitrarily chosen to focus on mammals; inherently not compassionate; and offer ineffective conservation solutions. Compassionate conservation arbitrarily focuses on charismatic species, notably large predators and megaherbivores. The philosophy is not compassionate when it leaves invasive predators in the environment to cause harm to vastly more individuals of native species or uses the fear of harm by apex predators to terrorize mesopredators. Hindering the control of exotic species (megafauna, predators) in situ will not improve the conservation condition of the majority of biodiversity. The positions taken by so-called compassionate conservationists on particular species and on conservation actions could be extended to hinder other forms of conservation, including translocations, conservation fencing, and fertility control. Animal welfare is incredibly important to conservation, but ironically compassionate conservation does not offer the best welfare outcomes to animals and is often ineffective in achieving conservation goals. Consequently, compassionate conservation may threaten public and governmental support for conservation because of the limited understanding of conservation problems by the general public.

Deconstrucción de la Conservación Compasiva Resumen La conservación compasiva se enfoca en cuatro principios: no causar daño; los individuos importan; la integración de los animales individualmente; y la coexistencia pacífica entre los humanos u los animales. Recientemente, la conservación compasiva ha sido promovida como una alternativa a la filosofía convencional de la conservación. Creemos que los ejemplos presentados por los conservacionistas compasivos han sido elegidos arbitraria o deliberadamente por estar enfocados en los mamíferos; por ser inherentes y no compasivos; y por ofrecer soluciones de conservación poco efectivas. La conservación compasiva se enfoca arbitrariamente en las especies carismáticas, principalmente los grandes depredadores y los megaherbívoros. La filosofía no es compasiva cuando deja que los depredadores invasores dentro del ambiente causen daño a un vasto número de individuos nativos o usa el miedo al daño por superdepredadores para aterrorizar a los mesodepredadores. El entorpecimiento del control de especies exóticas (megafauna, depredadores) in situ no mejorará las condiciones de conservación de la mayoría de la biodiversidad, incluso si los conservacionistas compasivos no dañan a los individuos exóticos. Las posiciones que toman los llamados conservacionistas compasivos sobre especies particulares y sobre las acciones de conservación podrían extenderse para entorpecer otros tipos de conservación, incluyendo las reubicaciones, el encercado para la conservación y el control de la fertilidad. El bienestar animal es increíblemente importante para la conservación e irónicamente, la conservación compasiva no ofrece los mejores resultados de bienestar para los animales y comúnmente es poco efectiva en el logro de los objetivos de conservación. Como consecuencia, la conservación compasiva puede poner en peligro el apoyo público y del gobierno que tiene la conservación debido al entendimiento poco limitado que tiene el público general sobre los problemas de conservación.

Spatial variation in anthropogenic mortality induces a source-sink system in a hunted mesopredator.

Lethal carnivore management is a prevailing strategy to reduce livestock predation. Intensity of lethal management varies according to land-use, where carnivores are more intensively hunted on farms relative to reserves. Variations in hunting intensity may result in the formation of a source-sink system where carnivores disperse from high-density to low-density areas. Few studies quantify dispersal between supposed sources and sinks-a fundamental requirement for source-sink systems. We used the black-backed jackal (Canis mesomelas) as a model to determine if heterogeneous anthropogenic mortality induces a source-sink system. We analysed 12 microsatellite loci from 554 individuals from lightly hunted and previously unhunted reserves, as well as heavily hunted livestock- and game farms. Bayesian genotype assignment showed that jackal populations displayed a hierarchical population structure. We identified two genetically distinct populations at the regional level and nine distinct subpopulations at the local level, with each cluster corresponding to distinct land-use types separated by various dispersal barriers. Migration, estimated using Bayesian multilocus genotyping, between reserves and farms was asymmetric and heterogeneous anthropogenic mortality induced source-sink dynamics via compensatory immigration. Additionally some heavily hunted populations also acted as source populations, exporting individuals to other heavily hunted populations. This indicates that heterogeneous anthropogenic mortality results in the formation of a complex series of interconnected sources and sinks. Thus, lethal management of mesopredators may not be an effective long-term strategy in reducing livestock predation, as dispersal and, more importantly, compensatory immigration may continue to affect population reduction efforts as long as dispersal from other areas persists.

Diet shifts by adult flightless dung beetles Circellium bacchus, revealed using DNA metabarcoding, reflect complex life histories.

Life history changes may change resource use. Such shifts are not well understood in the dung beetles, despite recognised differences in larval and adult feeding ability. We use the flightless dung beetle Circellium bacchus to explore such shifts, identifying dung sources of adults using DNA metabarcoding, and comparing these with published accounts of larval dung sources. C. bacchus is traditionally considered to specialise on the dung of large herbivores for both larval and adult feeding. We successfully extracted mammal DNA from 151 adult C. bacchus fecal samples, representing 16 mammal species (ranging from elephants to small rodents), many of which are hitherto undescribed in the diet. Adult C. bacchus showed clear dung source preferences, especially for large herbivores inhabiting dense-cover vegetation. Our approach also confirmed the presence of cryptic taxa in the study area, and we propose that this may be used for biodiversity survey and monitoring purposes. Murid rodent feces were the most commonly fed-upon dung source (77.5%) for adult C. bacchus, differing markedly from the large and megaherbivore dung sources used for larval rearing. These findings support the hypothesis of life history-specific shifts in resource use in dung beetles, and reveal a hitherto unsuspected, but ecologically important, role of these dung beetles in consuming rodent feces. The differences in feeding abilities of the larval and adult life history stages have profound consequences for their resource use and foraging strategies, and hence the ecological role of dung beetles. This principle and its ecological consequences should be explored in other scarabaeids.

Sub-optimal Application of a High SPF Sunscreen Prevents Epidermal DNA Damage in Vivo.

The cyclobutane pyrimidine dimer (CPD) is a potentially mutagenic DNA photolesion that is the basis of most skin cancers. There are no data on DNA protection by sunscreens under typical conditions of use. The study aim was to determine such protection, in phototypes I/II, with representative sunscreen-user application. A very high SPF formulation was applied at 0.75, 1.3 and 2.0 mg/cm2. Unprotected control skin was exposed to 4 standard erythema doses (SED) of solar simulated UVR, and sunscreen-treated sites to 30 SED. Holiday behaviour was also simulated by UVR exposure for 5 consecutive days. Control skin received 1 SED daily, and sunscreen-treated sites received 15 (all 3 application thicknesses) or 30 (2.0 mg/cm2) SED daily. CPD were assessed by quantitative HPLC-tandem mass spectrometry (HPLC-MS/MS) and semi-quantitative immunostaining. In comparison with unprotected control sites, sunscreen significantly (p ≤ 0.001-0.05) reduced DNA damage at 1.3 and 2.0 mg/cm2 in all cases. However, reduction with typical sunscreen use (0.75 mg/cm2) was non-significant, with the exception of HPLC-MS/MS data for the 5-day study (p <0.001). Overall, these results support sunscreen use as a strategy to reduce skin cancer, and demonstrate that public health messages must stress better sunscreen application to get maximal benefit.

The acute effects of ultraviolet radiation on the blood transcriptome are independent of plasma 25OHD3.

The molecular basis of many health outcomes attributed to solar ultraviolet radiation (UVR) is unknown. We tested the hypothesis that they may originate from transcriptional changes in blood cells. This was determined by assessing the effect of fluorescent solar simulated radiation (FSSR) on the transcriptional profile of peripheral blood pre- and 6h, 24h and 48h post-exposure in nine healthy volunteers. Expression of 20 genes was down-regulated and one was up-regulated at 6h after FSSR. All recovered to baseline expression at 24h or 48h. These genes have been associated with immune regulation, cancer and blood pressure; health effects attributed to vitamin D via solar UVR exposure. Plasma 25-hydroxyvitamin D3 [25OHD3] levels increased over time after FSSR and were maximal at 48h. The increase was more pronounced in participants with low basal 25OHD3 levels. Mediation analyses suggested that changes in gene expression due to FSSR were independent of 25OHD3 and blood cell subpopulations.

Obliquity-paced Pliocene West Antarctic ice sheet oscillations.

Thirty years after oxygen isotope records from microfossils deposited in ocean sediments confirmed the hypothesis that variations in the Earth's orbital geometry control the ice ages, fundamental questions remain over the response of the Antarctic ice sheets to orbital cycles. Furthermore, an understanding of the behaviour of the marine-based West Antarctic ice sheet (WAIS) during the 'warmer-than-present' early-Pliocene epoch ( approximately 5-3 Myr ago) is needed to better constrain the possible range of ice-sheet behaviour in the context of future global warming. Here we present a marine glacial record from the upper 600 m of the AND-1B sediment core recovered from beneath the northwest part of the Ross ice shelf by the ANDRILL programme and demonstrate well-dated, approximately 40-kyr cyclic variations in ice-sheet extent linked to cycles in insolation influenced by changes in the Earth's axial tilt (obliquity) during the Pliocene. Our data provide direct evidence for orbitally induced oscillations in the WAIS, which periodically collapsed, resulting in a switch from grounded ice, or ice shelves, to open waters in the Ross embayment when planetary temperatures were up to approximately 3 degrees C warmer than today and atmospheric CO(2) concentration was as high as approximately 400 p.p.m.v. (refs 5, 6). The evidence is consistent with a new ice-sheet/ice-shelf model that simulates fluctuations in Antarctic ice volume of up to +7 m in equivalent sea level associated with the loss of the WAIS and up to +3 m in equivalent sea level from the East Antarctic ice sheet, in response to ocean-induced melting paced by obliquity. During interglacial times, diatomaceous sediments indicate high surface-water productivity, minimal summer sea ice and air temperatures above freezing, suggesting an additional influence of surface melt under conditions of elevated CO(2).

Evaluating adaptive co-management as conservation conflict resolution: Learning from seals and salmon.

By linking iterative learning and knowledge generation with power-sharing, adaptive co-management (ACM) provides a potential solution to resolving complex social-ecological problems. In this paper we evaluate ACM as a mechanism for resolving conservation conflict using a case study in Scotland, where seal and salmon fishery stakeholders have opposing and entrenched objectives. ACM emerged in 2002, successfully resolving this long-standing conflict. Applying evaluation approaches from the literature, in 2011 we interviewed stakeholders to characterise the evolution of ACM, and factors associated with its success over 10 years. In common with other ACM cases, triggers for the process were shifts in slow variables controlling the system (seal and salmon abundance, public perceptions of seal shooting), and exogenous shocks (changes in legal mandates, a seal disease outbreak). Also typical of ACM, three phases of evolution were evident: emerging local leadership preparing the system for change, a policy window of opportunity, and stakeholder partnerships building the resilience of the system. Parameters maintaining ACM were legal mechanisms and structures, legal power held by government, and the willingness of all stakeholders to reach a compromise and experiment with an alternative governance approach. Results highlighted the critical role of government power and support in resolving conservation conflict, which may constrain the extent of local stakeholder-driven ACM. The evaluation also demonstrated how, following perceived success, the trajectory of ACM has shifted to a 'stakeholder apathy' phase, with declining leadership, knowledge exchange, stakeholder engagement, and system resilience. We discuss remedial actions required to revive the process, and the importance of long term government resourcing and alternative financing schemes for successful conflict resolution. Based on the results we present a generic indicator framework and participatory method for the longitudinal evaluation of ACM applied to conservation conflict resolution.

Estimating patient dose from x-ray tube output metrics: automated measurement of patient size from CT images enables large-scale size-specific dose estimates.

PURPOSE: To test the hypothesis that patient size can be accurately calculated from axial computed tomographic (CT) images, including correction for the effects of anatomy truncation that occur in routine clinical CT image reconstruction. MATERIALS AND METHODS: Institutional review board approval was obtained for this HIPAA-compliant study, with waiver of informed consent. Water-equivalent diameter (D(W)) was computed from the attenuation-area product of each image within 50 adult CT scans of the thorax and of the abdomen and pelvis and was also measured for maximal field of view (FOV) reconstructions. Linear regression models were created to compare D(W) with the effective diameter (D(eff)) used to select size-specific volume CT dose index (CTDI(vol)) conversion factors as defined in report 204 of the American Association of Physicists in Medicine. Linear regression models relating reductions in measured D(W) to a metric of anatomy truncation were used to compensate for the effects of clinical image truncation. RESULTS: In the thorax, D(W)versus D(eff) had an R(2) of 0.51 (n = 200, 50 patients at four anatomic locations); in the abdomen and pelvis, R(2) was 0.90 (n = 150, 50 patients at three anatomic locations). By correcting for image truncation, the proportion of clinically reconstructed images with an extracted D(W) within ±5% of the maximal FOV D(W) increased from 54% to 90% in the thorax (n = 3602 images) and from 95% to 100% in the abdomen and pelvis (6181 images). CONCLUSION: The D(W) extracted from axial CT images is a reliable measure of patient size, and varying degrees of clinical image truncation can be readily corrected. Automated measurement of patient size combined with CT radiation exposure metrics may enable patient-specific dose estimation on a large scale.

Elevated elephant density does not improve ecotourism opportunities: convergence in social and ecological objectives.

In order to sustainably conserve biodiversity, many protected areas, particularly private protected areas, must find means of self-financing. Ecotourism is increasingly seen as a mechanism to achieve such financial sustainability. However, there is concern that ecotourism operations are driven to achieve successful game-viewing, influencing the management of charismatic species. An abundance of such species, including the African elephant (Loxodonta africana), has been stocked in protected areas under the assumption that they will increase ecotourism value. At moderate to high densities, the impact of elephants is costly; numerous studies have documented severe changes in biodiversity through the impacts of elephants. Protected areas that focus on maintaining high numbers of elephants may therefore face a conflict between socioeconomic demands and the capacity of ecological systems. We address this conflict by analyzing tourist elephant-sighting records from six private and one statutory protected area, the Addo Elephant National Park (AENP), in the Eastern Cape Province of South Africa, in relation to elephant numbers. We found no relationship between elephant density and elephant-viewing success. Even though elephant density in the AENP increased over time, a hierarchical partitioning analysis indicated that elephant density was not a driver of tourist numbers. In contrast, annual tourist numbers for the AENP were positively correlated with general tourist numbers recorded for South Africa. Our results indicate that the socioeconomic and ecological requirements of protected areas in terms of tourism and elephants, respectively, converge. Thus, high elephant densities and their associated ecological costs are not required to support ecotourism operations for financial sustainability. Understanding the social and ecological feedbacks that dominate the dynamics of protected areas, particularly within private protected areas, can help to elucidate the management challenges of minimizing ecological trade-offs while meeting ecotourist demands and achieving sustainability.

Long­term monitoring reveals differing impacts of elephants on elements of a canopy shrub community.

The conservation management of southern Africa's elephants focuses on identifying and mitigating the extent and intensity of impacts on biological diversity. However, variation in the intensity of elephant effects between elements of biodiversity is seldom explored, which limits our ability to interpret the scale of the impacts. Our study quantifies >50 years of impacts in the succulent thickets of the Addo Elephant National Park, South Africa, contrasting hypotheses for the resilience of the canopy shrubs (a key functional guild) to elephants with those that argue the opposite. We also assess the impacts between elements of the community, ranging from community composition and structure to the structure of individual canopy species. We show the vulnerability of the canopy shrubs to transformation as the accumulated influences of elephants alter community composition and structure. The pattern of transformation is similar to that caused by domestic herbivores, which leads us to predict that elephants will eventually bring about landscape-level degradation and a significant loss of biodiversity. While we expected the canopy species to show similar declining trends in structure, providing insight into the response of the community as a whole, we demonstrate an uneven distribution of impacts between constituent elements; most of the canopy dominants exhibited little change, resisting removal. This implies that these canopy dominants might not be useful indicators of community change in thickets, a pattern that is likely repeated among the canopy trees of savanna systems. Our findings suggest that predicting elephant impacts, and finding solutions to the so-called "elephant problem," require a broader and more integrated understanding of the mechanisms driving the changes between elements of biodiversity at various spatial and temporal scales.

Wilder rangelands as a natural climate opportunity: Linking climate action to biodiversity conservation and social transformation.

Rangelands face threats from climate and land-use change, including inappropriate climate change mitigation initiatives such as tree planting in grassy ecosystems. The marginalization and impoverishment of rangeland communities and their indigenous knowledge systems, and the loss of biodiversity and ecosystem services, are additional major challenges. To address these issues, we propose the wilder rangelands integrated framework, co-developed by South African and European scientists from diverse disciplines, as an opportunity to address the climate, livelihood, and biodiversity challenges in the world's rangelands. More specifically, we present a Theory of Change to guide the design, monitoring, and evaluation of wilder rangelands. Through this, we aim to promote rangeland restoration, where local communities collaborate with regional and international actors to co-create new rangeland use models that simultaneously mitigate the impacts of climate change, restore biodiversity, and improve both ecosystem functioning and livelihoods.