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Clonal propagation enables favourable crop genotypes to be rapidly selected and multiplied. However, the absence of sexual propagation can lead to low genetic diversity and accumulation of deleterious mutations, which may eventually render crops less resilient to pathogens or environmental change. To better understand this trade-off, we characterize the domestication and contemporary genetic diversity of Enset (Ensete ventricosum), an indigenous African relative of bananas (Musa) and a principal starch staple for 20 million Ethiopians. Wild enset reproduction occurs strictly by sexual outcrossing, but for cultivation, it is propagated clonally and associated with diversification and specialization into hundreds of named landraces. We applied tGBS sequencing to generate genome-wide genotypes for 192 accessions from across enset's cultivated distribution, and surveyed 1340 farmers on enset agronomic traits. Overall, reduced heterozygosity in the domesticated lineage was consistent with a domestication bottleneck that retained 37% of wild diversity. However, an excess of putatively deleterious missense mutations at low frequency present as heterozygotes suggested an accumulation of mutational load in clonal domesticated lineages. Our evidence indicates that the major domesticated lineages initially arose through historic sexual recombination associated with a domestication bottleneck, followed by the amplification of favourable genotypes through an extended period of clonal propagation. Among domesticated lineages, we found a significant phylogenetic signal for multiple farmer-identified food, nutrition and disease resistance traits and little evidence of contemporary recombination. The development of future-climate adapted genotypes may require crop breeding, but outcrossing risks exposing deleterious alleles as homozygotes. This trade-off may partly explain the ubiquity and persistence of clonal propagation over recent centuries of comparative climate stability.
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Domesticación , Fitomejoramiento , Agricultura , Variación Genética , Fenotipo , FilogeniaRESUMEN
PREMISE: Oceanic islands offer the opportunity to understand evolutionary processes underlying rapid diversification. Along with geographic isolation and ecological shifts, a growing body of genomic evidence has suggested that hybridization can play an important role in island evolution. Here we use genotyping-by-sequencing (GBS) to understand the roles of hybridization, ecology, and geographic isolation in the radiation of Canary Island Descurainia (Brassicaceae). METHODS: We carried out GBS for multiple individuals of all Canary Island species and two outgroups. Phylogenetic analyses of the GBS data were performed using both supermatrix and gene tree approaches and hybridization events were examined using D-statistics and Approximate Bayesian Computation. Climatic data were analyzed to examine the relationship between ecology and diversification. RESULTS: Analysis of the supermatrix data set resulted in a fully resolved phylogeny. Species networks suggest a hybridization event has occurred for D. gilva, with these results being supported by Approximate Bayesian Computation analysis. Strong phylogenetic signals for temperature and precipitation indicate one major ecological shift within Canary Island Descurainia. CONCLUSIONS: Inter-island dispersal played a significant role in the diversification of Descurainia, with evidence of only one major shift in climate preferences. Despite weak reproductive barriers and the occurrence of hybrids, hybridization appears to have played only a limited role in the diversification of the group with a single instance detected. The results highlight the need to use phylogenetic network approaches that can simultaneously accommodate incomplete lineage sorting and gene flow when studying groups prone to hybridization; patterns that might otherwise be obscured in species trees.
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Hibridación Genética , Filogenia , España , Teorema de Bayes , GeografíaRESUMEN
Children and young people in contact with forensic child and adolescent mental health services present with more complex needs than young people in the general population. Recent policy in child and adolescent mental health has led to the implementation of new workstreams and programmes to improve service provision. This research examines the characteristics of children and young people referred to recently commissioned Community Forensic Child and Adolescent Services (F:CAMHS) and service activity during the first 24 months of service. The study is a national cohort study to describe the population and investigate service provision and access across England. Secondary data on 1311 advice cases and 1406 referrals are included in analysis. Findings show that 71.9% of the sample had accessed mainstream CAMHS before their referral, 50.9% had experienced/witnessed multiple traumatic events and 58.4% of young people presented with multiple difficulties. The results of the study highlight the complexity of the cohort and a need for interagency trauma-informed working. This is the first study to describe the characteristics of children and young people referred to Community F:CAMHS and provides valuable information on pathways and needs to inform service policy and provision.
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Servicios de Salud del Adolescente , Servicios de Salud Mental , Humanos , Niño , Adolescente , Estudios de Cohortes , Inglaterra , Derivación y ConsultaRESUMEN
According to Transparency International, of the US$7.5 trillion spent globally on health each year, US$500 billion is lost to corruption.1 This article deals with the topic of corruption in the health sector in sub-Saharan Africa with a focus on how it affects persons living with HIV and their families. It begins with a definition of corruption and outlines the types of activities, people and institutions that fall within that definition in the context of HIV/AIDS. Examples are provided of what happens in practice and the types of persons (in terms of their societal roles) who yield to corruption, and how and why they commit it. The effects of corruption in health and in the fight against HIV/AIDS are then considered, drawing on published research on the costs to institutions and society. For example, HIV prevalence among women is higher than men, yet their reliance on health services plagued by corruption makes them vulnerable to abuse, blocking access to vital contraceptive, HIV testing, and reproductive and child health services. Attention is then focused on the factors that encourage the adoption of corrupt practices and what approaches have been taken to try to counter them. This includes a review and analysis of the steps that have been taken to strengthen compliance, governance and accountability and why attempts to deal with corruption have met with little success. This article suggests a new approach - harnessing digitalisation - to combat corruption more quickly and effectively, pointing out that corruption is both a major factor contributing to inefficiency and is harming peoples' health. This article aims to raise interest and renew efforts in fighting corruption in health.
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Síndrome de Inmunodeficiencia Adquirida , Infecciones por VIH , Masculino , Humanos , Femenino , Niño , Síndrome de Inmunodeficiencia Adquirida/epidemiología , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , Responsabilidad Social , Costos y Análisis de Costo , África del Sur del SaharaRESUMEN
The vast, deep, volatile-ice-filled basin informally named Sputnik Planum is central to Pluto's vigorous geological activity. Composed of molecular nitrogen, methane, and carbon monoxide ices, but dominated by nitrogen ice, this layer is organized into cells or polygons, typically about 10 to 40 kilometres across, that resemble the surface manifestation of solid-state convection. Here we report, on the basis of available rheological measurements, that solid layers of nitrogen ice with a thickness in excess of about one kilometre should undergo convection for estimated present-day heat-flow conditions on Pluto. More importantly, we show numerically that convective overturn in a several-kilometre-thick layer of solid nitrogen can explain the great lateral width of the cells. The temperature dependence of nitrogen-ice viscosity implies that the ice layer convects in the so-called sluggish lid regime, a unique convective mode not previously definitively observed in the Solar System. Average surface horizontal velocities of a few centimetres a year imply surface transport or renewal times of about 500,000 years, well under the ten-million-year upper-limit crater retention age for Sputnik Planum. Similar convective surface renewal may also occur on other dwarf planets in the Kuiper belt, which may help to explain the high albedos shown by some of these bodies.
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Inferring the processes responsible for the rich endemic diversity of oceanic island floras is important for our understanding of plant evolution and setting practical conservation priorities. This requires an accurate knowledge of phylogenetic relationships, which have often been difficult to resolve due to a lack of genetic variation. We employed genotyping-by-sequencing (GBS) to investigate how geographical isolation, habitat shifts, and hybridisation have contributed to the evolution of diversity observed in Argyranthemum Webb (Asteraceae), the largest genus of flowering plants endemic to the Macaronesian archipelagos. Species relationships were resolved, and biogeographical stochastic mapping identified intra-island speciation as the most frequent biogeographic process underlying diversification, contrary to the prevailing view in Argyranthemum and the Canary Islands. D-statistics revealed significant evidence of hybridisation between lineages co-occurring on the same island, however there was little support for the hypothesis that hybridisation may be responsible for the occurrence of nonmonophyletic multi-island endemic (MIE) species. Geographic isolation, habitat shifts and hybridisation have all contributed to the diversification of Argyranthemum, with intra-island speciation found to be more frequent than previously thought. Morphological convergence is also proposed to explain the occurrence of nonmonophyletic MIE species. This study reveals greater complexity in the evolutionary processes generating Macaronesian endemic diversity.
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Asteraceae , Asteraceae/genética , Ecosistema , Especiación Genética , Islas , Océanos y Mares , Filogenia , EspañaRESUMEN
Well-characterized examples of homoploid hybrid speciation (HHS) are rare in nature, yet they offer the potential to study a number of evolutionary processes. In this study, we investigate putative homoploid hybrid species in the genus Argyranthemum (Asteraceae), a group of plants endemic to the Macaronesian archipelagos of the North Atlantic Ocean. We specifically address a number of knowledge gaps surrounding the origin(s) of A. sundingii and A. lemsii, which are thought to be derived from the same parental cross. Comparisons of leaf morphology suggest that A. sundingii and A. lemsii are distinct from their parental progenitors and distinguishable from each other based on leaf area. Ecological niche modelling (ENM) demonstrated that the homoploid hybrid species occupy novel habitats that are intermediate relative to the parental species. Nuclear simple sequence repeat markers (SSRs) and single nucleotide polymorphism (SNP) data indicate that the homoploid hybrid species are distinct from the parental taxa, while population-level sampling of chloroplast SSRs and approximate Bayesian computation show that A. sundingii and A. lemsii are independently derived from the same parental cross. As such, Argyranthemum represents an example of independent homoploid hybrid speciation events with evidence of divergence in leaf morphology and adaptation to novel intermediate habitats. On oceanic islands, which are often typified by steep ecological gradients and inhabited by recently derived species with weak reproductive barriers, multiple HHS events from the same parental cross are not only possible but also likely to have played a more important role in oceanic island radiations than we currently think.
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Asteraceae/clasificación , Especiación Genética , Teorema de Bayes , Ecosistema , Genética de Población , Hibridación Genética , Islas , Repeticiones de Microsatélite , Modelos Biológicos , Hojas de la Planta/anatomía & histología , Polimorfismo de Nucleótido Simple , EspañaRESUMEN
Ecological isolation is increasingly thought to play an important role in speciation, especially for the origin and reproductive isolation of homoploid hybrid species. However, the extent to which divergent and/or transgressive gene expression changes are involved in speciation is not well studied. In this study, we employ comparative transcriptomics to investigate gene expression changes associated with the origin and evolution of two homoploid hybrid plant species, Argyranthemum sundingii and A. lemsii (Asteraceae). As there is no standard methodology for comparative transcriptomics, we examined five different pipelines for data assembly and analysing gene expression across the four species (two hybrid and two parental). We note biases and problems with all pipelines, and the approach used affected the biological interpretation of the data. Using the approach that we found to be optimal, we identify transcripts showing DE between the parental taxa and between the homoploid hybrid species and their parents; in several cases, putative functions of these DE transcripts have a plausible role in ecological adaptation and could be the cause or consequence of ecological speciation. Although independently derived, the homoploid hybrid species have converged on similar expression phenotypes, likely due to adaptation to similar habitats.
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Asteraceae , Hibridación Genética , Especiación Genética , Transcriptoma , Asteraceae/genética , EcosistemaRESUMEN
A recurring feature of oceanic archipelagos is the presence of adaptive radiations that generate endemic, species-rich clades that can offer outstanding insight into the links between ecology and evolution. Recent developments in evolutionary genomics have contributed towards solving long-standing questions at this interface. Using a comprehensive literature search, we identify studies spanning 19 oceanic archipelagos and 110 putative adaptive radiations, but find that most of these radiations have not yet been investigated from an evolutionary genomics perspective. Our review reveals different gaps in knowledge related to the lack of implementation of genomic approaches, as well as undersampled taxonomic and geographic areas. Filling those gaps with the required data will help to deepen our understanding of adaptation, speciation, and other evolutionary processes.
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Evolución Biológica , Especiación Genética , Filogenia , Ecología , GenómicaRESUMEN
There has been increased research in recent years on incidents within adolescent inpatient psychiatric units, although findings to date have been somewhat inconsistent. We analysed all reported incidents by 37 consecutively discharged patients from a mixed sex adolescent forensic hospital. Findings include a very high overall rate of incidents. A small number of female patients with emerging emotionally unstable personality disorder accounted for the majority of violent incidents and other incidents. Almost all the patients assaulted someone during their admission. Patients on civil sections of the Mental Health Act had just as many incidents as patients on forensic sections. The vast majority of assaults were on staff. Peak times for incidents were the end of each day when education sessions were timetabled and the beginning of the night shift.
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Unidades Hospitalarias , Servicio de Psiquiatría en Hospital , Violencia/estadística & datos numéricos , Adolescente , Inglaterra , Femenino , Humanos , Masculino , Trastornos de la Personalidad/epidemiología , Estudios RetrospectivosRESUMEN
The New Horizons spacecraft returned images and compositional data showing that terrains on Pluto span a variety of ages, ranging from relatively ancient, heavily cratered areas to very young surfaces with few-to-no impact craters. One of the regions with very few impact craters is dominated by enormous rises with hummocky flanks. Similar features do not exist anywhere else in the imaged solar system. Here we analyze the geomorphology and composition of the features and conclude this region was resurfaced by cryovolcanic processes, of a type and scale so far unique to Pluto. Creation of this terrain requires multiple eruption sites and a large volume of material (>104 km3) to form what we propose are multiple, several-km-high domes, some of which merge to form more complex planforms. The existence of these massive features suggests Pluto's interior structure and evolution allows for either enhanced retention of heat or more heat overall than was anticipated before New Horizons, which permitted mobilization of water-ice-rich materials late in Pluto's history.
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The first investigation into PBDE levels in food produced from flood-prone land on industrial river catchments was conducted. In August 2008 samples of cows' milk, along with grass and soil were taken from 5 pairs of flood-prone and control farms on the River Trent (Central UK). The sum of 7 BDE congeners (28, 47, 99, 100, 153, 154, and 183) was calculated. Higher PBDE levels occurred in soil on flood-prone compared to control farms (median 770 vs 280 ng/kg dry weight). These higher levels were not reflected in the grass samples indicating that PBDE contamination on soils is not transferred efficiently to grass. This observation alongside the fact that cows on flood-prone farms spend time on non-flood-prone land and are fed substantial quantities of commercial feed are reasons why higher PBDE levels were not found in milk from flood-prone farms (median 300 vs 250 ng/kg fat weight). Similar BDE47/BDE99 ratios were observed in soil and grass samples compared to the PBDE product commonly used in the UK, indicating few differences in source-pathway transfer efficiencies between congeners. The BDE47/BDE99 ratio in the milk samples was greater than those in the grass and feed indicating differential food to milk transfer efficiencies between congeners.
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Contaminantes Ambientales/análisis , Inundaciones , Éteres Difenilos Halogenados/análisis , Leche/química , Animales , Bovinos , Poaceae/química , Ríos , Suelo/química , Reino UnidoRESUMEN
Introduction: Young people in contact with forensic child and adolescent mental health services present with more complex needs than young people in the general population. Recent policy has led to the implementation of new workstreams and programmes to improve service provision for this cohort. This paper aims to present the protocol for a national study examining the impact and implementation of Community Forensic Child and Adolescent Mental Health Services (F:CAMHS). Methods and analysis: The study will use a mixed-methods Realist Evaluation design. Quantitative service activity and feedback data will be collected from all 13 sites, as well as questionnaires from staff. Non-participant observations and qualitative interviews will be conducted with staff, young people and parents/guardians from four focus study sites. An economic evaluation will examine whether Community F:CAMHS provides good value for money. The results will be triangulated to gain an in-depth understanding of young people's, parents/guardians' and staff experiences of the service. Ethics and dissemination: Ethical approval was granted by the Health Research Association and UCL Ethics. The results will be disseminated via project reports, feedback to sites, peer-reviewed journal publications and conference presentations.
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Pluto is covered by numerous deposits of methane, either diluted in nitrogen or as methane-rich ice. Within the dark equatorial region of Cthulhu, bright frost containing methane is observed coating crater rims and walls as well as mountain tops, providing spectacular resemblance to terrestrial snow-capped mountain chains. However, the origin of these deposits remained enigmatic. Here we report that they are composed of methane-rich ice. We use high-resolution numerical simulations of Pluto's climate to show that the processes forming them are likely to be completely different to those forming high-altitude snowpack on Earth. The methane deposits may not result from adiabatic cooling in upwardly moving air like on our planet, but from a circulation-induced enrichment of gaseous methane a few kilometres above Pluto's plains that favours methane condensation at mountain summits. This process could have shaped other methane reservoirs on Pluto and help explain the appearance of the bladed terrain of Tartarus Dorsa.
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A complex mixture of dissolved organic contaminants, emanating from a many decades-old, residual, dense non-aqueous phase liquid (DNAPL) source, migrates through unconfined, moderately heterogeneous, glacial-derived sediments and sedimentary rock in a residential area of Dane County, Wisconsin, USA. A portion of this contaminant plume intersects a large man-made pond, roughly 400 m downgradient of the source zone. Depth-discrete, multilevel groundwater sampling, detailed sedimentological logs, and hydraulic head profiles were used to delineate the spatial distribution of hydraulic, geologic, organic contaminant, and redox hydrochemical conditions within the established plume along two transects immediately upgradient of the pond. Twenty-one contaminants were detected and classified into four major contaminant groups: chlorinated ethenes, chlorinated ethanes, aromatics (BTEX: benzene, toluene, ethylbenzene, xylene), and aliphatic ketones. Within the glacial sediments and shallow bedrock, zones of reductive dechlorination of chlorinated ethenes and ethanes were juxtaposed with zones of BTEX and ketone degradation. Spatial heterogeneity in the concentration and distribution of contaminant groups and redox conditions was observed over lateral distances of tens of meters and vertical distances of tens of centimeters along the two transects. Although the site was situated in a complex glacial depositional environment, lithologic and hydraulic heterogeneity surprisingly only had a modest influence on the spatial distribution of plume contaminants. Depth-discrete sampling along paired, closely spaced transects (~20 m apart) was essential to assess internal plume composition/concentration evolution along flow paths with strong attenuation over short migration distances. This study shows how paired, highly resolved transects can enhance understanding of transverse and longitudinal variability in areas where contaminant-induced redox conditions control reaction zones and strong plume attenuation.
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Agua Subterránea , Contaminantes Químicos del Agua , Anciano , Etano , Geología , Humanos , Contaminantes Químicos del Agua/análisisRESUMEN
PREMISE OF THE STUDY: Oceanic islands offer unparalleled opportunities to investigate evolutionary processes such as adaptation and speciation. However, few genomic resources are available for oceanic island endemics. In this study, we publish transcriptome sequences from three Macaronesian endemic plant species (Argyranthemum broussonetii [Asteraceae], Descurainia bourgaeana [Brassicaceae], and Echium wildpretii [Boraginaceae]) that are representative of lineages that have radiated in the region. In addition, the utility of transcriptome data for marker development is demonstrated. METHODS AND RESULTS: Transcriptomes from the three plant species were sequenced, assembled, and annotated. Between 1972 and 2282 simple sequence repeats (SSRs) were identified for each taxon. Primers were designed and tested for 30 of the candidate SSRs identified in Argyranthemum, of which 12 amplified well across three species and eight were polymorphic. CONCLUSIONS: We demonstrate here that a single transcriptome sequence is sufficient to identify hundreds of polymorphic SSR markers. The SSRs are applicable to a wide range of questions relating to the evolution of island lineages.
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NASA's New Horizons spacecraft has revealed the complex geology of Pluto and Charon. Pluto's encounter hemisphere shows ongoing surface geological activity centered on a vast basin containing a thick layer of volatile ices that appears to be involved in convection and advection, with a crater retention age no greater than ~10 million years. Surrounding terrains show active glacial flow, apparent transport and rotation of large buoyant water-ice crustal blocks, and pitting, the latter likely caused by sublimation erosion and/or collapse. More enigmatic features include tall mounds with central depressions that are conceivably cryovolcanic and ridges with complex bladed textures. Pluto also has ancient cratered terrains up to ~4 billion years old that are extensionally faulted and extensively mantled and perhaps eroded by glacial or other processes. Charon does not appear to be currently active, but experienced major extensional tectonism and resurfacing (probably cryovolcanic) nearly 4 billion years ago. Impact crater populations on Pluto and Charon are not consistent with the steepest impactor size-frequency distributions proposed for the Kuiper belt.
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OBJECTIVES: Children who have been maltreated are at increased risk of further maltreatment. Identification of those at highest risk of further maltreatment is a priority for professionals working in child protection services. The current study is intended to consolidate and expand on previous work on recurrence of child maltreatment. It has sought to identify risk factors for maltreatment recurrence in the recent literature in the expectation that this may help in the practical identification of children at risk. METHODS: We conducted a systematic review of cohort studies published between 2003 and 2009, identifying factors associated with maltreatment recurrence in children. Studies included demonstrated differing levels of substantiation of maltreatment. RESULTS: Fifteen studies met inclusion criteria but showed significant heterogeneity, varying in setting, recruitment of subjects, types of maltreatment considered and length of follow-up. Previous findings were replicated and expanded in the current study in relation to a range of factors, including rates of maltreatment recurrence, maltreatment types, frequency of previous episodes of maltreatment, child and family considerations, home environment and service provision. Factors were identified irrespective of level of maltreatment substantiation. CONCLUSION: This study provides further systematic evidence of the existence of a number of factors associated with child maltreatment recurrence. It points to the possibility of practical application of its findings within the wider context of decision making in child protection services, with the ultimate aim of reducing recurrence of maltreatment in individual cases.