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The alien invasive silver carpHypophthalmichthys molitrixestablished a self-sustaining feral population in an oligotrophic impoundment, Flag Boshielo Dam, in South Africa. The ability of this population to persist in a dam with low algal biomass (median annual suspended chlorophylla= 0.08 µg l−1), and limited access to rivers considered large enough for successful spawning, has implications for their invasive potential in other systems. Stomach content and stable isotope analysis were used to assess the trophic ecology ofH. molitrix, which was then compared with indigenous Mozambique tilapiaOreochromis mossambicus, on a seasonal basis during 2011.Hypophthalmichthys molitrixare generalist filter feeders, with a diet consisting primarily of sediment, vegetative detritus, dinoflagellates and diatoms. The dominance of sediments in their stomachs suggests occasional benthic scavenging. However,H. molitrixoccupied a higher trophic level (TL = 2.8) than expected, suggesting that this population subsidised their diet with an unidentified dietary constituent, characterised by enriched nitrogen values. Although the stomach contents indicated dietary overlap betweenH. molitrixandO. mossambicus, stable isotopes revealed fine-scale resource partitioning, despite both species occupying the same trophic level. Nonetheless, the persistence of this feralH. molitrixpopulation in an oligotrophic impoundment highlights their phenotypic plasticity. [ABSTRACT FROM PUBLISHER]

The scientific method is predicated on transparency-yet the pace at which transparent research practices are being adopted by the scientific community is slow. The replication crisis in psychology showed that published findings employing statistical inference are threatened by undetected errors, data manipulation and data falsification. To mitigate these problems and bolster research credibility, open data and preregistration practices have gained traction in the natural and social sciences. However, the extent of their adoption in different disciplines is unknown. We introduce computational procedures to identify the transparency of a research field using large-scale text analysis and machine learning classifiers. Using political science and international relations as an illustrative case, we examine 93 931 articles across the top 160 political science and international relations journals between 2010 and 2021. We find that approximately 21% of all statistical inference papers have open data and 5% of all experiments are preregistered. Despite this shortfall, the example of leading journals in the field shows that change is feasible and can be effected quickly., Competing Interests: We declare we have no competing interests., (© 2024 The Authors.)

Functional redundancy, the potential for the functional role of one species to be fulfilled by another, is a key determinant of ecosystem viability. Scavenging transfers huge amount of energy through ecosystems and is, therefore, crucial for ecosystem viability and healthy ecosystem functioning. Despite this, relatively few studies have examined functional redundancy in scavenger communities. Moreover, the results of these studies are mixed and confined to a very limited range of habitat types and taxonomic groups. This study attempts to address this knowledge gap by conducting a field experiment in an undisturbed natural environment assessing functional roles and redundancy in vertebrate and invertebrate scavenging communities in a South African savanna. We used a large-scale field experiment to suppress ants in four 1 ha plots in a South African savanna and paired each with a control plot. We distributed three types of small food bait: carbohydrate, protein and seed, across the plots and excluded vertebrates from half the baits using cages. Using this combination of ant suppression and vertebrate exclusion, allowed us explore the contribution of non-ant invertebrates, ants and vertebrates in scavenging and also to determine whether either ants or vertebrates were able to compensate for the loss of one another. In this study, we found the invertebrate community carried out a larger proportion of overall scavenging services than vertebrates. Moreover, although scavenging was reduced when either invertebrates or vertebrates were absent, the presence of invertebrates better mitigated the functional loss of vertebrates than did the presence of vertebrates against the functional loss of invertebrates. There is a commonly held assumption that the functional role of vertebrate scavengers exceeds that of invertebrate scavengers; our results suggest that this is not true for small scavenging resources. Our study highlights the importance of invertebrates for securing healthy ecosystem functioning both now and into the future. We also build upon many previous studies which show that ants can have particularly large effects on ecosystem functioning. Importantly, our study suggests that scavenging in some ecosystems may be partly resilient to changes in the scavenging community, due to the potential for functional compensation by vertebrates and ants., (© 2024 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.)

There is burgeoning interest in how artificial light at night (ALAN) interacts with disease vectors, particularly mosquitoes. ALAN can alter mosquito behaviour and biting propensity, and so must alter disease transfer rates. However, most studies to date have been laboratory-based, and it remains unclear how ALAN modulates disease vector risk. Here, we identify five priorities to assess how artificial light can influence disease vectors in socio-ecological systems. These are to (i) clarify the mechanistic role of artificial light on mosquitoes, (ii) determine how ALAN interacts with other drivers of global change to influence vector disease dynamics across species, (iii) determine how ALAN interacts with other vector suppression strategies, (iv) measure and quantify the impact of ALAN at scales relevant for vectors, and (v) overcome the political and social barriers in implementing it as a novel vector suppression strategy. These priorities must be addressed to evaluate the costs and benefits of employing appropriate ALAN regimes in complex socio-ecological systems if it is to reduce disease burdens, especially in the developing world. This article is part of the theme issue 'Light pollution in complex ecological systems'.

Species can be both native and alien to a given administrative region. Here we present the first consolidated inventory of these 'native-alien populations' for South Africa, and provide an overview of the data it contains. To gather data, literature searches were performed and experts were consulted both directly and via an on-line survey. Putative native-alien populations were then scored based on a newly developed protocol. The final inventory contains information on 77 native species from 49 families across nine classes that have formed 132 native-alien populations across the terrestrial, freshwater, and marine environments. The phenomenon is rare when compared to the prevalence of related phenomena, such as alien species introduced from other countries (2033 alien species in South Africa), but is under-reported. However, they pose a specific problem for regulators and managers and their importance will likely increase with global change. These data will be integrated with an existing alien species list and, we hope, will provide a useful foundation to address the issue. We encourage those working on biodiversity to contribute more records., (© 2023. The Author(s).)

Deadwood is a large global carbon store with its store size partially determined by biotic decay. Microbial wood decay rates are known to respond to changing temperature and precipitation. Termites are also important decomposers in the tropics but are less well studied. An understanding of their climate sensitivities is needed to estimate climate change effects on wood carbon pools. Using data from 133 sites spanning six continents, we found that termite wood discovery and consumption were highly sensitive to temperature (with decay increasing >6.8 times per 10°C increase in temperature)-even more so than microbes. Termite decay effects were greatest in tropical seasonal forests, tropical savannas, and subtropical deserts. With tropicalization (i.e., warming shifts to tropical climates), termite wood decay will likely increase as termites access more of Earth's surface.

The dead donor rule is fundamental to transplant ethics. The rule states that organ procurement must not commence until the donor is both dead and formally pronounced so, and by the same token, that procurement of organs must not cause the death of the donor. In a separate area of medical practice, there has been intense controversy around the participation of physicians in the execution of capital prisoners. These two apparently disparate topics converge in a unique case: the intimate involvement of transplant surgeons in China in the execution of prisoners via the procurement of organs. We use computational text analysis to conduct a forensic review of 2838 papers drawn from a dataset of 124 770 Chinese-language transplant publications. Our algorithm searched for evidence of problematic declarations of brain death during organ procurement. We find evidence in 71 of these reports, spread nationwide, that brain death could not have properly been declared. In these cases, the removal of the heart during organ procurement must have been the proximate cause of the donor's death. Because these organ donors could only have been prisoners, our findings strongly suggest that physicians in the People's Republic of China have participated in executions by organ removal., (© 2022 The Authors. American Journal of Transplantation published by Wiley Periodicals LLC on behalf of The American Society of Transplantation and the American Society of Transplant Surgeons.)

Interaction between two biological control agents released against Lantana camara L. (sensu lato) (Verbenaceae) was studied in replicated semi-field plots. Caged plants under semi-field conditions were inoculated with Uroplata girardi Pic (Coleoptera: Chrysomelidae) and Ophiomyia camarae Spencer (Diptera: Agromyzidae), either alone or in combination, to investigate the extent to which co-infestation of the two agents affects the reproductive capacity and growth of their host. At the end of the trial, both single and combined attacks by the two agents had no effect on stem diameter, stem height, and canopy width. However, uncaged control plants were heavily attacked by Teleonemia scrupulosa Stål (Hemiptera: Tingidae), and therefore became significantly shorter than all the caged plants in all the treatments. When confined alone, feeding damage by O. camarae resulted in higher reduction of fruit and flower biomass relative to that caused by U. girardi alone. However, when confined alone, U. girardi caused higher reductions in leaf density and fruit biomass than when combined with O. camarae. Single attack by O. camarae caused higher reduction in flower biomass than simultaneous attack by both agents. Above-ground biomass of all single and combined treatment plants were significantly lower than those of the caged control plants. Uncaged control plants exposed to heavy attack by T. scrupulosa did not produce flowers and fruits, and their above-ground biomass was significantly lower than those of caged control plants. Overall, the study showed that simultaneous attack by the two herbivores alters their herbivory, thereby affecting reproductive capacity and growth of their host., (© 2021. Sociedade Entomológica do Brasil.)

Background: The massive transfusion protocol (MTP) is designed to quickly provide blood products at a fixed ratio for the exsanguinating patient. At our academic medical center, the frequency of MTP activation increased over 10-fold between 2008 and 2015, putting inordinate stress on our transfusion service., Study Design and Methods: Gathering a large number of relevant stakeholders, we performed a multidisciplinary root cause analysis (RCA) in response to the acute clinical need to reform our MTP., Results: Through the RCA, we identified four principal opportunities for improvement (OFI) associated with our MTP: education, stewardship, process improvement, and communication. Through the deployment of new approaches to each of these OFI, we reduced MTP activations, blood product waste, and transfusion service technologist stress., Conclusion: The MTP is amenable to improvement, and, although time intensive, the RCA process yields significant favorable effects: improving communication with colleagues, reducing stress within the transfusion service, and improving resource utilization. Activation of the MTP at our institution is now more aligned with its primary purpose: rapidly providing large quantities of blood products to exsanguinating patients., (© 2021 AABB.)

Biological invasions often transcend political boundaries, but the capacity of countries to prevent invasions varies. How this variation in biosecurity affects the invasion risks posed to the countries involved is unclear. We aimed to improve the understanding of how the biosecurity of a country influences that of its neighbours. We developed six scenarios that describe biological invasions in regions with contiguous countries. Using data from alien species databases, socio-economic and biodiversity data and species distribution models, we determined where 86 of 100 of the world's worst invasive species are likely to invade and have a negative impact in the future. Information on the capacity of countries to prevent invasions was used to determine whether such invasions could be avoided. For the selected species, we predicted 2,523 discrete invasions, most of which would have significant negative impacts and are unlikely to be prevented. Of these invasions, approximately a third were predicted to spread from the country in which the species first establishes to neighbouring countries where they would cause significant negative impacts. Most of these invasions are unlikely to be prevented as the country of first establishment has a low capacity to prevent invasions or has little incentive to do so as there will be no impact in that country. Regional biosecurity is therefore essential to prevent future harmful biological invasions. In consequence, we propose that the need for increased regional co-operation to combat biological invasions be incorporated in global biodiversity targets., (© 2020 John Wiley & Sons Ltd.)

Background: Since 2010 the People's Republic of China has been engaged in an effort to reform its system of organ transplantation by developing a voluntary organ donation and allocation infrastructure. This has required a shift in the procurement of organs sourced from China's prison and security apparatus to hospital-based voluntary donors declared dead by neurological and/or circulatory criteria. Chinese officials announced that from January 1, 2015, hospital-based donors would be the sole source of organs. This paper examines the availability, transparency, integrity, and consistency of China's official transplant data., Methods: Forensic statistical methods were used to examine key deceased organ donation datasets from 2010 to 2018. Two central-level datasets - published by the China Organ Transplant Response System (COTRS) and the Red Cross Society of China - are tested for evidence of manipulation, including conformance to simple mathematical formulae, arbitrary internal ratios, the presence of anomalous data artefacts, and cross-consistency. Provincial-level data in five regions are tested for coherence, consistency, and plausibility, and individual hospital data in those provinces are examined for consistency with provincial-level data., Results: COTRS data conforms almost precisely to a mathematical formula (which first appeared to be a general quadratic, but with further confirmatory data was discovered to be a simpler one-parameter quadratic) while Central Red Cross data mirrors it, albeit imperfectly. The analysis of both datasets suggests human-directed data manufacture and manipulation. Contradictory, implausible, or anomalous data artefacts were found in five provincial datasets, suggesting that these data may have been manipulated to enforce conformity with central quotas. A number of the distinctive features of China's current organ procurement and allocation system are discussed, including apparent misclassification of nonvoluntary donors as voluntary., Conclusion: A variety of evidence points to what the authors believe can only be plausibly explained by systematic falsification and manipulation of official organ transplant datasets in China. Some apparently nonvoluntary donors also appear to be misclassified as voluntary. This takes place alongside genuine voluntary organ transplant activity, which is often incentivized by large cash payments. These findings are relevant for international interactions with China's organ transplantation system.

The trait-based approach to ecology promises to provide a mechanistic understanding of species distributions and ecosystem functioning. Typically, trait analyses focus on average species trait values and assume that intraspecific variation is small or negligible. Recent work has shown, however, that intraspecific trait variation can often contribute substantially to total trait variation. Whilst many studies have investigated intraspecific variation in plants, very few have done so for invertebrates. There is no research on the level of intraspecific trait variation in ants (Hymenoptera: Formicidae), despite the fact that there is a growing body of literature using ant morphological trait data and demonstrating that these insects play important roles in many ecosystems and food webs. Here, we investigate the intraspecific variability of four commonly used ant morphological traits from 23 species from the Maloti-Drakensberg Mountains of southern Africa. In total, we measured 1145 different individuals and made 6870 trait measurements. Intraspecific variation accounted for only 1-4% of total trait variation for each of the four traits we analysed. We found no links between intraspecific variation, phylogeny and elevation. On average, six individuals generated robust species means but under biased sampling scenarios 20 individuals were needed. The low levels of intraspecific morphological variation that we find suggest that the approach of using mean species traits is valid, in this fauna at least. Regardless, we encourage ant trait ecologists to measure greater numbers of individuals, especially across gradients, to shed further light on intraspecific variation in this functionally important group of insects.

Predictive analytics monitoring, the use of patient data to provide continuous risk estimation of deterioration, is a promising new application of big data analytical techniques to the care of individual patients. We tested the hypothesis that continuous display of novel electronic risk visualization of respiratory and cardiovascular events would impact intensive care unit (ICU) patient outcomes. In an adult tertiary care surgical trauma ICU, we displayed risk estimation visualizations on a large monitor, but in the medical ICU in the same institution we did not. The risk estimates were based solely on analysis of continuous cardiorespiratory monitoring. We examined 4275 individual patient records within a 7 month time period preceding and following data display. We determined cases of septic shock, emergency intubation, hemorrhage, and death to compare rates per patient care pre-and post-implementation. Following implementation, the incidence of septic shock fell by half (p < 0.01 in a multivariate model that included age and APACHE) in the surgical trauma ICU, where the data were continuously on display, but by only 10% (p = NS) in the control Medical ICU. There were no significant changes in the other outcomes. Display of a predictive analytics monitor based on continuous cardiorespiratory monitoring was followed by a reduction in the rate of septic shock, even when controlling for age and APACHE score.

Predicting and understanding the biological response to future climate change is a pressing challenge for humanity. In the 21st century, many species will move into higher latitudes and higher elevations as the climate warms. In addition, the relative abundances of species within local assemblages are likely to change. Both effects have implications for how ecosystems function. Few biodiversity forecasts, however, take account of both shifting ranges and changing abundances. We provide a novel analysis predicting the potential changes to assemblage-level relative abundances in the 21st century. We use an established relationship linking ant abundance and their colour and size traits to temperature and UV-B to predict future abundance changes. We also predict future temperature driven range shifts and use these to alter the available species pool for our trait-mediated abundance predictions. We do this across three continents under a low greenhouse gas emissions scenario (RCP2.6) and a business-as-usual scenario (RCP8.5). Under RCP2.6, predicted changes to ant assemblages by 2100 are moderate. On average, species richness will increase by 26%, while species composition and relative abundance structure will be 26% and 30% different, respectively, compared with modern assemblages. Under RCP8.5, however, highland assemblages face almost a tripling of species richness and compositional and relative abundance changes of 66% and 77%. Critically, we predict that future assemblages could be reorganized in terms of which species are common and which are rare: future highland assemblages will not simply comprise upslope shifts of modern lowland assemblages. These forecasts reveal the potential for radical change to montane ant assemblages by the end of the 21st century if temperature increases continue. Our results highlight the importance of incorporating trait-environment relationships into future biodiversity predictions. Looking forward, the major challenge is to understand how ecosystem processes will respond to compositional and relative abundance changes., (© 2019 John Wiley & Sons Ltd.)

Objectives: The objective of this study is to investigate whether papers reporting research on Chinese transplant recipients comply with international professional standards aimed at excluding publication of research that: (1) involves any biological material from executed prisoners; (2) lacks Institutional Review Board (IRB) approval and (3) lacks consent of donors., Design: Scoping review based on Arksey and O'Mallee's methodological framework., Data Sources: Medline, Scopus and Embase were searched from January 2000 to April 2017., Eligibility Criteria: We included research papers published in peer-reviewed English-language journals reporting on outcomes of research involving recipients of transplanted hearts, livers or lungs in mainland China., Data Extraction and Synthesis: Data were extracted by individual authors working independently following training and benchmarking. Descriptive statistics were compiled using Excel., Results: 445 included studies reported on outcomes of 85 477 transplants. 412 (92.5%) failed to report whether or not organs were sourced from executed prisoners; and 439 (99%) failed to report that organ sources gave consent for transplantation. In contrast, 324 (73%) reported approval from an IRB. Of the papers claiming that no prisoners' organs were involved in the transplants, 19 of them involved 2688 transplants that took place prior to 2010, when there was no volunteer donor programme in China., Discussion: The transplant research community has failed to implement ethical standards banning publication of research using material from executed prisoners. As a result, a large body of unethical research now exists, raising issues of complicity and moral hazard to the extent that the transplant community uses and benefits from the results of this research. We call for retraction of this literature pending investigation of individual papers., Competing Interests: Competing interests: Dr AB is a member of the New Zealand Advocacy & Initiatives Committee (NZAIC) of the International Coalition to End Transplant Abuse in China, Dr BB has nothing to disclose, Dr RC has nothing to disclose, Dr RC-W is a member of the Australian Advocacy and Initiatives Committee of the International Coalition to End Transplant Abuse in China, Professor MFS is a member of the Ethics Committee of Doctors Against Forced Organ Harvesting, and a member of the Australian Advocacy and Initiatives Committee of the International Coalition to End Transplant Abuse in China, MPR reports that he is an occasional expert contributor to the International Coalition to End Transplant Abuse in China, Professor WR is a Director of the NGO ’International Coalition to End Transplant Abuse in China' and is chair of its International Advisory Committee., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Woody encroachment can lead to a complete switch from open habitats to dense thickets, and has the potential to greatly alter the biodiversity and ecological functioning of grassy ecosystems across the globe. Plant litter decomposition is a critical ecosystem process fundamental to nutrient cycling and global carbon dynamics, yet little is known about how woody encroachment might alter this process. We compared grass decay rates of heavily encroached areas with adjacent nonencroached open areas in a semi-arid South African savanna using litterbags that allowed or excluded invertebrates. We also assessed the effect of woody encroachment on the activity of termites- dominant decomposer organisms in savanna systems. We found a significant reduction in decomposition rates within encroached areas, with litter taking twice as long to decay compared with open savanna areas. Moreover, invertebrates were more influential on grass decomposition in open areas and termite activity was substantially lower in encroached areas, particularly during the dry season when activity levels were reduced to almost zero. Our results suggest that woody encroachment created an unfavourable environment for invertebrates, and termites in particular, leading to decreased decomposition rates in these areas. We provide the first quantification of woody encroachment altering the functioning of African savanna ecosystems through the slowing of aboveground plant decomposition. Woody encroachment is intensifying across the globe, and our results suggest that substantial changes to the carbon balance and biodiversity of grassy biomes could occur., (© 2018 John Wiley & Sons Ltd.)

The global shipping network facilitates the transportation and introduction of marine and terrestrial organisms to regions where they are not native, and some of these organisms become invasive. South Africa was used as a case study to evaluate the potential for shipping to contribute to the introduction and establishment of marine and terrestrial alien species (i.e. establishment debt) and to assess how this varies across shipping routes and seasons. As a proxy for the number of species introduced (i.e. 'colonisation pressure') shipping movement data were used to determine, for each season, the number of ships that visited South African ports from foreign ports and the number of days travelled between ports. Seasonal marine and terrestrial environmental similarity between South African and foreign ports was then used to estimate the likelihood that introduced species would establish. These data were used to determine the seasonal relative contribution of shipping routes to South Africa's marine and terrestrial establishment debt. Additionally, distribution data were used to identify marine and terrestrial species that are known to be invasive elsewhere and which might be introduced to each South African port through shipping routes that have a high relative contribution to establishment debt. Shipping routes from Asian ports, especially Singapore, have a particularly high relative contribution to South Africa's establishment debt, while among South African ports, Durban has the highest risk of being invaded. There was seasonal variation in the shipping routes that have a high relative contribution to the establishment debt of the South African ports. The presented method provides a simple way to prioritise surveillance effort and our results indicate that, for South Africa, port-specific prevention strategies should be developed, a large portion of the available resources should be allocated to Durban, and seasonal variations and their consequences for prevention strategies should be explored further.

Introduction There is an increased demand for intensive care unit (ICU) beds. We sought to determine if we could create a safe surge capacity model to increase ICU capacity by treating ICU patients in the post-anaesthesia care unit (PACU) utilizing a collaborative model between an ICU service and a telemedicine service during peak ICU bed demand. Methods We evaluated patients managed by the surgical critical care service in the surgical intensive care unit (SICU) compared to patients managed in the virtual intensive care unit (VICU) located within the PACU. A retrospective review of all patients seen by the surgical critical care service from January 1st 2008 to July 31st 2011 was conducted at an urban, academic, tertiary centre and level 1 trauma centre. Results Compared to the SICU group ( n = 6652), patients in the VICU group ( n = 1037) were slightly older (median age 60 (IQR 47-69) versus 58 (IQR 44-70) years, p = 0.002) and had lower acute physiology and chronic health evaluation (APACHE) II scores (median 10 (IQR 7-14) versus 15 (IQR 11-21), p < 0.001). The average amount of time patients spent in the VICU was 13.7 + /-9.6 hours. In the VICU group, 750 (72%) of patients were able to be transferred directly to the floor; 287 (28%) required subsequent admission to the surgical intensive care unit. All patients in the VICU group were alive upon transfer out of the PACU while mortality in the surgical intensive unit cohort was 5.5%. Discussion A collaborative care model between a surgical critical care service and a telemedicine ICU service may safely provide surge capacity during peak periods of ICU bed demand. The specific patient populations for which this approach is most appropriate merits further investigation.

Border control is one of the major approaches used by countries to limit the number of organisms introduced as stowaways. However, it is not feasible to inspect all passengers, cargo and vehicles entering a country, and so efforts need to be prioritised. Here we use South Africa as a case study to assess, based on tourism and trade data and climate matching techniques, the number of stowaway species that might be introduced ('colonisation pressure') and the likelihood that once introduced, these organisms will establish ('likelihood of establishment'). These results were used to explore how the number of species that are likely to establish ('establishment debt') varies across donor regions and seasons. A simple theoretical model was then used to compare four strategies for prioritising border control inspections: no prioritisation; based on colonisation pressure; based on likelihood of establishment; and based on both colonisation pressure and likelihood of establishment. Establishment debt was greatest in southern hemisphere spring and autumn when South Africa is climatically similar to northern hemisphere countries with which there are strong, consistent trade and tourism links (i.e. colonisation pressure varied little seasonally, but likelihood of establishment did vary across the seasons). Prioritising inspections based on both colonisation pressure and the likelihood of establishment was clearly the most effective strategy, with this strategy detecting at least 6% more potential invaders than the other strategies. While there are many practical limitations to the implementation of such prioritised inspection strategies, the results highlight the importance of national and regional studies of establishment debt., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

African savannas are highly seasonal with a diverse array of both mammalian and invertebrate herbivores, yet herbivory studies have focused almost exclusively on mammals. We conducted a 2-yr exclosure experiment in South Africa's Kruger National Park to measure the relative impact of these two groups of herbivores on grass removal at both highly productive patches (termite mounds) and in the less productive savanna matrix. Invertebrate and mammalian herbivory was greater on termite mounds, but the relative importance of each group changed over time. Mammalian offtake was higher than invertebrates in the dry season, but can be eclipsed by invertebrates during the wet season when this group is more active. Our results demonstrate that invertebrates play a substantial role in savanna herbivory and should not be disregarded in attempts to understand the impacts of herbivory on ecosystems.

Aim: Beta diversity describes the variation in species composition between sites and can be used to infer why different species occupy different parts of the globe. It can be viewed in a number of ways. First, it can be partitioned into two distinct patterns: turnover and nestedness. Second, it can be investigated from either a species identity or a functional-trait point of view. We aim to document for the first time how these two aspects of beta diversity vary in response to a large environmental gradient., Location: Maloti-Drakensberg Mountains, southern Africa., Methods: We sampled ant assemblages along an extensive elevational gradient (900-3000 m a.s.l.) twice yearly for 7 years, and collected functional-trait information related to the species' dietary and habitat-structure preferences. We used recently developed methods to partition species and functional beta diversity into their turnover and nestedness components. A series of null models were used to test whether the observed beta diversity patterns differed from random expectations., Results: Species beta diversity was driven by turnover, but functional beta diversity was composed of both turnover and nestedness patterns at different parts of the gradient. Null models revealed that deterministic processes were likely to be responsible for the species patterns but that the functional changes were indistinguishable from stochasticity., Main Conclusions: Different ant species are found with increasing elevation, but they tend to represent an increasingly nested subset of the available functional strategies. This finding is unique and narrows down the list of possible factors that control ant existence across elevation. We conclude that diet and habitat preferences have little role in structuring ant assemblages in montane environments and that some other factor must be driving the non-random patterns of species turnover. This finding also highlights the importance of distinguishing between different kinds of beta diversity.

Understanding which species are introduced and become invasive, and why, are central questions in invasion science. Comparative studies on model taxa have provided important insights, but much more needs to be done to unravel the context dependencies of these findings. The cactus family (Cactaceae), one of the most popular horticultural plant groups, is an interesting case study. Hundreds of cactus species have been introduced outside their native ranges; a few of them are among the most damaging invasive plant species in the world. We reviewed the drivers of introductions and invasions in the family and seek insights that can be used to minimize future risks. We compiled a list of species in the family and determined which have been recorded as invasive. We also mapped current global distributions and modelled the potential global distributions based on distribution data of known invasive taxa. Finally, we identified whether invasiveness is phylogenetically clustered for cacti and whether particular traits are correlated with invasiveness. Only 57 of the 1922 cactus species recognized in this treatment have been recorded as invasive. There are three invasion hotspots: South Africa (35 invasive species recorded), Australia (26 species) and Spain (24 species). However, there are large areas of the world with climates suitable for cacti that are at risk of future invasion-in particular, parts of China, eastern Asia and central Africa. The invasive taxa represent an interesting subset of the total species pool. There is a significant phylogenetic signal: invasive species occur in 2 of the 3 major phylogenetic clades and in 13 of the 130 genera. This phylogenetic signal is not driven by human preference, i.e. horticultural trade, but all invasive species are from 5 of the 12 cactus growth forms. Finally, invasive species tend to have significantly larger native ranges than non-invasive species, and none of the invasive species are of conservation concern in their native range. These results suggest fairly robust correlates of invasiveness that can be used for proactive management and risk assessments., (Published by Oxford University Press on behalf of the Annals of Botany Company.)

Global change is driving a massive rearrangement of the world's biota. Trajectories of distributional shifts are shaped by species traits, the recipient environment and driving forces with many of the driving forces directly due to human activities. The relative importance of each in determining the distributions of introduced species is poorly understood. We consider 11 Australian Acacia species introduced to South Africa for different reasons (commercial forestry, dune stabilization and ornamentation) to determine how features of the introduction pathway have shaped their invasion history. Projections from species distribution models (SDMs) were developed to assess how the reason for introduction influences the similarity between climatic envelopes in native and alien ranges. A lattice model for an idealized invasion was developed to assess the relative contribution of intrinsic traits and introduction dynamics on the abundance and extent over the course of simulated invasions. SDMs show that alien populations of ornamental species in South Africa occupy substantially different climate space from their native ranges, whereas species introduced for forestry occupy a similar climate space in native and introduced ranges. This may partly explain the slow spread rates observed for some alien ornamental plants. Such mismatches are likely to become less pronounced with the current drive towards 'eco gardens' resulting in more introductions of ornamental species with a close climate match between native and newly introduced regions. The results from the lattice model showed that the conditions associated with the introduction pathway (especially introduction pressure) dominate early invasion dynamics. The placement of introduction foci in urban areas limited the extent and abundance of invasive populations. Features of introduction events appear to initially mask the influence of intrinsic species traits on invasions and help to explain the relative success of species introduced for different purposes. Introduction dynamics therefore can have long-lasting influences on the outcomes of species redistributions, and must be explicitly considered in management plans., (© 2013 John Wiley & Sons Ltd.)

The RNA World Hypothesis posits that the first self-replicating molecules were RNAs. RNA self-replicases are, in general, assumed to have employed nucleotide 5'-polyphosphates (or their analogues) as substrates for RNA polymerization. The mechanism by which these substrates might be synthesized with sufficient abundance to supply a growing and evolving population of RNAs is problematic for evolutionary hypotheses because non-enzymatic synthesis and assembly of nucleotide 5'-triphosphates (or other analogously activated phosphodiester species) is inherently difficult. However, nucleotide 2',3'-cyclic phosphates are also phosphodiesters, and are the natural and abundant products of RNA degradation. These have previously been dismissed as viable substrates for prebiotic RNA synthesis. We propose that the arguments for their dismissal are based on a flawed assumption, and that nucleotide 2',3'-cyclic phosphates in fact possess several significant, advantageous properties that indeed make them particularly viable substrates for prebiotic RNA synthesis. An RNA World hypothesis based upon the polymerization of nucleotide 2',3'-cyclic phosphates possesses additional explanatory power in that it accounts for the observed ribozyme "fossil record", suggests a viable mechanism for substrate transport across lipid vesicle boundaries of primordial proto-cells, circumvents the problems of substrate scarcity and implausible synthetic pathways, provides for a primitive but effective RNA replicase editing mechanism, and definitively explains why RNA, rather than DNA, must have been the original catalyst. Finally, our analysis compels us to propose that a fundamental and universal property that drives the evolution of living systems, as well as pre-biotic replicating molecules (be they composed of RNA or protein), is that they exploit chemical reactions that already possess competing kinetically-preferred and thermodynamically-preferred pathways in a manner that optimizes the balance between the two types of pathways.

Background: Intensive care units (ICUs) function frequently at capacity, requiring incoming critically ill patients to be placed in alternate geographically distinct ICUs. In some medical ICU populations, "boarding" in an overflow ICU has been associated with increased mortality. We hypothesized that surgical ICU patients experience more complications when boarding in an overflow ICU and that the frequency of these complications are greatest in boarders farthest from the home unit (HU)., Methods: A 5-year (June 2005 to June 2010) retrospective review of a prospectively maintained ICU database was performed, and demographics, severity of illness, length of stay, and incidence of ICU complications were extracted. Distances between boarding patients' rooms and the HU were measured. Complications occurring in patients located in the same floor (BUSF) and different floor (BUDF) boarding units were compared and stratified by distance from HU to the patient room. Logistic regression was used to develop control for known confounders., Results: A total of 7,793 patients were admitted to the HU and 833 to a boarding unit (BUSF, n = 712; BUDF, n = 121). Boarders were younger, had a lower length of stay, and Acute Physiology and Chronic Health Evaluation II and were more often trauma/emergency surgery patients. Compared with in-HU patients, the incidence of aspiration pneumonia (2.2% vs. 3.6%, p < 0.01) was greater in BUSF patients and highest in those farthest from the HU (odds ratio [OR], 2.39; p = 0.01). Delirium occurred less often in HU than in BUDF patients (3.3% vs. 8.3 %, p < 0.01), and both delirium (OR, 6.09, p < 0.01) and ventilator-associated pneumonia (OR, 4.49, p < 0.05) were more frequent in patients farther from the HU., Conclusion: Certain ICU complications occur more frequently in boarding patients particularly if they are located on a different floor or far from the HU. When surgical ICU bed availability forces overflow admissions to non-home ICUs, greater interdisciplinary awareness, education, and training may be needed to ensure equivalent care and outcomes., Level of Evidence: Epidemiologic study, level III. Therapeutic study, level IV.

An RNA enzyme has been developed that catalyzes the joining of oligonucleotide substrates to form additional copies of itself, undergoing self-replication with exponential growth. The enzyme also can cross-replicate with a partner enzyme, resulting in their mutual exponential growth and enabling self-sustained Darwinian evolution. The opportunity for inventive evolution within this synthetic genetic system depends on the diversity of the evolving population, which is limited by the catalytic efficiency of the enzyme. Directed evolution was used to improve the efficiency of the enzyme and increase its exponential growth rate to 0.14 min(-1), corresponding to a doubling time of 5 min. This is close to the limit of 0.21 min(-1) imposed by the rate of product release, but sufficient to enable more than 80 logs of growth per day., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Much ecological research relies on existing multispecies distribution datasets. Such datasets, however, can vary considerably in quality, extent, resolution or taxonomic coverage. We provide a framework for a spatially-explicit evaluation of geographical representation within large-scale species distribution datasets, using the comparison of an occurrence atlas with a range atlas dataset as a working example. Specifically, we compared occurrence maps for 3773 taxa from the widely-used Atlas Florae Europaeae (AFE) with digitised range maps for 2049 taxa of the lesser-known Atlas of North European Vascular Plants. We calculated the level of agreement at a 50-km spatial resolution using average latitudinal and longitudinal species range, and area of occupancy. Agreement in species distribution was calculated and mapped using Jaccard similarity index and a reduced major axis (RMA) regression analysis of species richness between the entire atlases (5221 taxa in total) and between co-occurring species (601 taxa). We found no difference in distribution ranges or in the area of occupancy frequency distribution, indicating that atlases were sufficiently overlapping for a valid comparison. The similarity index map showed high levels of agreement for central, western, and northern Europe. The RMA regression confirmed that geographical representation of AFE was low in areas with a sparse data recording history (e.g., Russia, Belarus and the Ukraine). For co-occurring species in south-eastern Europe, however, the Atlas of North European Vascular Plants showed remarkably higher richness estimations. Geographical representation of atlas data can be much more heterogeneous than often assumed. Level of agreement between datasets can be used to evaluate geographical representation within datasets. Merging atlases into a single dataset is worthwhile in spite of methodological differences, and helps to fill gaps in our knowledge of species distribution ranges. Species distribution dataset mergers, such as the one exemplified here, can serve as a baseline towards comprehensive species distribution datasets.

Interhospital transfer (IHT) is associated with mortality in medical and mixed intensive care units (ICUs), but few studies have examined this relationship in a surgical ICU (SICU) setting. We hypothesized that IHT is associated with increased mortality in SICU patients relative to ICU patients admitted within the hospital. We reviewed SICU and transfer center databases from a tertiary academic center over a 2-year period. Inclusion criteria included age 18 years or older and SICU admission 24 hours or greater. Demographic data, admission service, and Acute Physiology and Chronic Health Evaluation (APACHE) II scores were captured. The primary end point was ICU mortality. Univariate logistic regression was used to test the association between variables and mortality. Factors found to be associated with mortality at P < 0.1 were entered into a multivariable model. Of 4542 admissions, 416 arrived by IHT. Compared with the non-IHT group, the IHT group was older (age 58.3 years [interquartile range, 47.8 to 70.6] vs. 57.8 years [interquartile range, 44.1 to 68.8] years, P = 0.036), sicker (APACHE II score 16.5 [interquartile range, 12 to 23] vs. 14 [interquartile range, 10 to 20], P < 0.001), and more likely to be white (82% [n = 341] vs. 69% [n = 2865], P < 0.001). Mortality rates in IHT patients were highest on the emergency surgery (18%), transplant surgery (16%), and gastrointestinal surgery (8%) services. After adjusting for age and APACHE II score, IHT remained a risk factor for ICU mortality (odds ratio, 1.60; 95% confidence interval, 1.04 to 2.45; P = 0.032) in SICU patients. Interhospital transfer is an independent risk factor for mortality in the SICU population; this risk is unevenly distributed through service lines. Further efforts to determine the cause of this association are warranted.

The general notion of an "RNA World" is that, in the early development of life on the Earth, genetic continuity was assured by the replication of RNA and genetically encoded proteins were not involved as catalysts. There is now strong evidence indicating that an RNA World did indeed exist before DNA- and protein-based life. However, arguments regarding whether life on Earth began with RNA are more tenuous. It might be imagined that all of the components of RNA were available in some prebiotic pool, and that these components assembled into replicating, evolving polynucleotides without the prior existence of any evolved macromolecules. A thorough consideration of this "RNA-first" view of the origin of life must reconcile concerns regarding the intractable mixtures that are obtained in experiments designed to simulate the chemistry of the primitive Earth. Perhaps these concerns will eventually be resolved, and recent experimental findings provide some reason for optimism. However, the problem of the origin of the RNA World is far from being solved, and it is fruitful to consider the alternative possibility that RNA was preceded by some other replicating, evolving molecule, just as DNA and proteins were preceded by RNA.

Multiple releases of insect agents intended to target a single plant pest species could result in competitive interactions that in turn might affect the community structure of the phytophagous insects. Two leaf-feeding biological control agents, Uroplata girardi Pic (Coleoptera: Chrysomelidae) and Ophiomyia camarae Spencer (Dipetera: Agromyzidae), were released against the weed Lantana camara L. (Verbenaceae) in South Africa in the 1970s and 2001, respectively. Since the population explosion of O. camarae in 2005, a decline of U. girardi populations had been observed in KwaZulu-Natal (KZN) humid coast, leading to speculation that negative interaction may be operating between the agents. The study therefore was conducted to determine the competitive effect of O. camarae on U. girardi. The study showed that 76% of O. camarae larval mines were formed on uninfested (clean) compared with only 24% formed on U. girardi-infested leaves, suggesting that the fly chose to lay more eggs on clean leaves. Almost the same number of U. girardi larval mines was formed on both O. camarae-infested and clean leaves, indicating that U. girardi females in this case oviposited indiscriminately on the two types of leaves. The survival of U. girardi was 53.8% when reared on clean leaves compared with only 14.6% survival on O. camarae-infested leaves. At the end of the sampling period, densities of U. girardi was over two times higher in single-species than in combined-species treatment. Releasing both agents together did not significantly affect O. camarae densities during the sampling period. In the field, O. camarae densities increased rapidly from spring to autumn, whereas those of U. girardi remained consistently low during the same period. The bias toward oviposition on clean leaves in O. camarae enables its larvae to avoid unfavorable encounters with U. girardi larvae, thus enhancing its development and survival. The apparent inability of U. girardi to distinguish between suitable and unsuitable leaves for oviposition could compromise the fitness of this beetle, and this could explain the suppression of U. girardi populations during summer when O. camarae populations begin to increase rapidly. This study provides evidence for an asymmetric interaction between two introduced agents, and therefore highlights the importance of conducting interaction studies on agents with extensive niche overlap before their release into the environment.

The crystallographic phase problem is the primary bottleneck encountered when attempting to solve macromolecular structures for which no close crystallographic structural homologues are known. Typically, isomorphous "heavy-atom" replacement and/or anomalous dispersion methods must be used in such cases to obtain experimentally-determined phases. Even three-dimensional NMR structures of the same macromolecule are often not sufficient to solve the crystallographic phase problem. RNA crystal structures present additional challenges due to greater difficulty in obtaining suitable heavy-atom derivatives. We present a unique approach to solve the phase problem for novel RNA crystal structures that has enjoyed a reasonable degree of success. This approach involves modeling only those portions of the RNA sequence whose structure can be predicted readily, i.e., the individual A-form helical regions and well-known stem-loop sub-structures. We have found that no prior knowledge of how the helices and other structural elements are arranged with respect to one another in three-dimensional space, or in some cases, even the sequence, is required to obtain a useable solution to the phase problem, using simultaneous molecular replacement of a set of generic helical RNA fragments., (Copyright © 2010 Elsevier Inc. All rights reserved.)

The L1 ligase is an in vitro selected ribozyme that uses a noncanonically base-paired ligation site to catalyze regioselectively and regiospecifically the 5' to 3' phosphodiester bond ligation, a reaction relevant to origin of life hypotheses that invoke an RNA world scenario. The L1 ligase crystal structure revealed two different conformational states that were proposed to represent the active and inactive forms. It remains an open question as to what degree these two conformers persist as stable conformational intermediates in solution, and along what pathway are they able to interconvert. To explore these questions, we have performed a series of molecular dynamics simulations in explicit solvent of the inactive-active conformational switch in L1 ligase. Four simulations were performed departing from both conformers in both the reactant and product states, in addition to a simulation where local unfolding in the active state was induced. From these simulations, along with crystallographic data, a set of four virtual torsion angles that span two evolutionarily conserved and restricted regions were identified as dynamical hinge points in the conformational switch transition. The ligation site visits three distinct states characterized by hydrogen bond patterns that are correlated with the formation of specific contacts that may promote catalysis. The insights gained from these simulations contribute to a more detailed understanding of the coupled catalytic/conformational switch mechanism of L1 ligase that may facilitate the design and engineering of new catalytic riboswitches.

Two correlative approaches to the challenge of ecological niche modeling (genetic algorithm, maximum entropy) were used to estimate the potential global distribution of the invasive fruit fly, Bactrocera invadens, based on associations between known occurrence records and a set of environmental predictor variables. The two models yielded similar estimates, largely corresponding to Equatorial climate classes with high levels of precipitation. The maximum entropy approach was somewhat more conservative in its evaluation of suitability, depending on thresholds for presence/absence that are selected, largely excluding areas with distinct dry seasons; the genetic algorithm models, in contrast, indicate that climate class as partly suitable. Predictive tests based on independent distributional data indicate that model predictions are quite robust. Field observations in Benin and Tanzania confirm relationships between seasonal occurrences of this species and humidity and temperature.

The crystallographic phase problem [Muirhead & Perutz (1963), Nature (London), 199, 633-638] remains the single major impediment to obtaining a three-dimensional structure of a macromolecule once suitable crystals have been obtained. Recently, it was found that it was possible to solve the structure of a 142-nucleotide L1 ligase ribozyme heterodimer that possesses no noncrystallographic symmetry without heavy-atom derivatives, anomalous scattering atoms or other modifications and without a model of the tertiary structure of the ribozyme [Robertson & Scott (2007), Science, 315, 1549-1553]. Using idealized known RNA secondary-structural fragments such as A-form helices and GNRA tetraloops in an iterative molecular-replacement procedure, it was possible to obtain an estimated phase set that, when subjected to solvent flattening, yielded an interpretable electron-density map with minimized model bias, allowing the tertiary structure of the ribozyme to be solved. This approach has also proven successful with other ribozymes, structured RNAs and RNA-protein complexes.

Life originated, according to the RNA World hypothesis, from self-replicating ribozymes that catalyzed ligation of RNA fragments. We have solved the 2.6 angstrom crystal structure of a ligase ribozyme that catalyzes regiospecific formation of a 5' to 3' phosphodiester bond between the 5'-triphosphate and the 3'-hydroxyl termini of two RNA fragments. Invariant residues form tertiary contacts that stabilize a flexible stem of the ribozyme at the ligation site, where an essential magnesium ion coordinates three phosphates. The structure of the active site permits us to suggest how transition-state stabilization and a general base may catalyze the ligation reaction required for prebiotic RNA assembly.