122 research outputs found
Fire and climate: contrasting pressures on tropical Andean timberline species
Department of Biological Sciences; Florida Institute of Technology; Melbourne FL USA Department of Biological Sciences; Florida Institute of Technology; Melbourne FL USA Department of Biological Sciences; Florida Institute of Technology; Melbourne FL USA Geography, College of Life & Environmental Sciences; University of Exeter; Exeter UK Department of Biological Sciences; Florida Institute of Technology; Melbourne FL USA CEPSAR; The Open University; Milton Keynes UK Instituto de Geología; Universidad Nacional Autónoma de México; Ciudad Universitaria; Mexico City Mexico Department of Forest and Soil Sciences; University of Natural Resources and Life Sciences Vienna; Vienna Austria Department of Biology and Center for Energy; Environment and Sustainability; Wake Forest University; Winston Salem NC USACopyright © 2015 John Wiley & Sons Ltd.Aim: The aim was to test competing hypotheses regarding migration of the Andean timberline within the last 2000 years.
Location: The upper forest limit in Manu National Park, Peru.
Methods: A randomized stratified design provided 21 soil profiles from forested sites just below the timberline, 15 from puna grassland sites just above the timberline and 15 from the transitional habitat at the puna–forest boundary. From each profile a surface sample (hereafter modern) and a sample from the base of the organic horizon (hereafter historical) were collected. Pollen and charcoal were analysed from the modern and historical layers of the 51 soil profiles. A chronological framework was provided by 24 14C dates. Data were ordinated as modern and historical groups and the temporal trends illustrated by Procrustes rotation.
Results: The organic layer from the soil profiles represented the last 600–2000 years. Fire was much more abundant in all habitat types (puna, transitional and forested) in the modern compared with the historical groups. Samples that had historically been in puna just above the timberline showed encroachment by woody species. Samples that had been forested were still classified as forest but their composition had become more transitional. Sites that were transitional appeared to represent a new or expanded class of sites that was far less abundant historically.
Main conclusions: Our results are consistent with ongoing warming causing an upslope migration of species, although not necessarily of the timberline. Weedy fire-tolerant species are spreading upslope, creating a transitional forest, softening the boundary between forest and puna. Simultaneously, fire introduced to improve grazing outside the park has increasingly penetrated the forest and is causing the upper timberline to shift towards more fire-tolerant and weedy species. Consequently, both the form of the ecotone between forest and grassland and the species composition of these forests is changing and is expected to continue to change, representing a shifting baseline for what is considered to be natural.Gordon and Betty Moore Foundation Andes-to-Amazon programmeBlue Moon FundNational Science Foundatio
The Cerenkov effect revisited: from swimming ducks to zero modes in gravitational analogs
We present an interdisciplinary review of the generalized Cerenkov emission
of radiation from uniformly moving sources in the different contexts of
classical electromagnetism, superfluid hydrodynamics, and classical
hydrodynamics. The details of each specific physical systems enter our theory
via the dispersion law of the excitations. A geometrical recipe to obtain the
emission patterns in both real and wavevector space from the geometrical shape
of the dispersion law is discussed and applied to a number of cases of current
experimental interest. Some consequences of these emission processes onto the
stability of condensed-matter analogs of gravitational systems are finally
illustrated.Comment: Lecture Notes at the IX SIGRAV School on "Analogue Gravity" in Como,
Italy from May 16th-21th, 201
Long-distance dispersal of pigeons and doves generated new ecological opportunities for host-switching and adaptive radiation by their parasites.
Adaptive radiation is an important mechanism of organismal diversification and can be triggered by new ecological opportunities. Although poorly studied in this regard, parasites are an ideal group in which to study adaptive radiations because of their close associations with host species. Both experimental and comparative studies suggest that the ectoparasitic wing lice of pigeons and doves have adaptively radiated, leading to differences in body size and overall coloration. Here, we show that long-distance dispersal by dove hosts was central to parasite diversification because it provided new ecological opportunities for parasites to speciate after host-switching. We further show that among extant parasite lineages host-switching decreased over time, with cospeciation becoming the more dominant mode of parasite speciation. Taken together, our results suggest that host dispersal, followed by host-switching, provided novel ecological opportunities that facilitated adaptive radiation by parasites
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Pathology reporting of hepatoblastoma resections: recommendations from the international collaboration on cancer reporting
Aims
Hepatoblastoma is the most common primary malignant tumour of the liver diagnosed in children and its incidence is increasing worldwide. Ongoing international clinical trials and scientific collaborative efforts are attempting to standardize the diagnosis, risk stratification and management of young patients diagnosed with this rare cancer, which includes surgical resection of the tumour. Here we report the international consensus-based dataset for the pathology reporting of hepatoblastoma resection specimens. The dataset was developed under the auspices of the International Collaboration on Cancer Reporting (ICCR), a global alliance of international pathology and cancer organizations.
Methods and results
According to the ICCR's guidelines for dataset development, an international expert panel including paediatric pathologists and a paediatric oncologist specialized in liver tumours developed a set of core and non-core data items for hepatoblastoma resection specimens based on critical review and discussion of current evidence available. Members of the panel were specialists working in tertiary paediatric hospitals, central reviewers for international paediatric liver tumours consortia and/or involved in paediatric liver tumour trials expert committees. Commentaries were provided to support each data item, explaining the rationale for selecting them as a ‘core’ or ‘non-core’ elements, their clinical relevance and highlighting potential areas of lack of evidence, including clinical, macroscopic, microscopic and ancillary testing considerations. The hepatoblastoma dataset was finalized and ratified following international public consultation and is published on the ICCR website for wide implementation.
Conclusion
This is the first international dataset developed by an international expert panel for reporting hepatoblastoma resection specimens aimed to promote high-quality, standardized pathology reporting of these rare paediatric liver tumours. The adoption and implementation of this hepatoblastoma data set, freely available worldwide on the ICCR website (www.iccr-cancer.org/data-sets), will facilitate accurate reporting and enhance the consistency of data collection, support retrospective and inform prospective research and ultimately help to improve clinical outcomes of children with hepatoblastoma
Trans-ethnic analysis of metabochip data identifies two new loci associated with BMI
Objective:Body mass index (BMI) is commonly used to assess obesity, which is associated with numerous diseases and negative health outcomes. BMI has been shown to be a heritable, polygenic trait, with close to 100 loci previously identified and replicated in multiple populations. We aim to replicate known BMI loci and identify novel associations in a trans-ethnic study population.Subjects:Using eligible participants from the Population Architecture using Genomics and Epidemiology consortium, we conducted a trans-ethnic meta-analysis of 102 514 African Americans, Hispanics, Asian/Native Hawaiian, Native Americans and European Americans. Participants were genotyped on over 200 000 SNPs on the Illumina Metabochip custom array, or imputed into the 1000 Genomes Project (Phase I). Linear regression of the natural log of BMI, adjusting for age, sex, study site (if applicable), and ancestry principal components, was conducted for each race/ethnicity within each study cohort. Race/ethnicity-specific, and combined meta-analyses used fixed-effects models.Results:We replicated 15 of 21 BMI loci included on the Metabochip, and identified two novel BMI loci at 1q41 (rs2820436) and 2q31.1 (rs10930502) at the Metabochip-wide significance threshold (P\u3c2.5 × 10 \u27 7). Bioinformatic functional investigation of SNPs at these loci suggests a possible impact on pathways that regulate metabolism and adipose tissue.Conclusion:Conducting studies in genetically diverse populations continues to be a valuable strategy for replicating known loci and uncovering novel BMI associations
Schooling for conflict transformation : a case study from Northern Uganda
Civil wars impede progress towards the Millennium Development Goals. As many conflicts erupt within a short time, it is important to know what may increase the chances of sustainable peace. Access to education is a factor but relatively little is known about the contribution of what students learn in school. This thesis aims to respond to a research gap by addressing the foll owing question: 'How can schooling contribute to conflict transformation?'
Significant curricular approaches that may be used after civil war - peace education, human rights education and citizenship education - are assessed for their strengths and weaknesses. As no single approach is found to be sufficient for conflict transformation, a framework is proposed based on three fundamental concepts: (i) truth seeking; (ii) reconciliation; and (iii) inclusive citizenship.
This framework is examined through a qualitative case study of curriculum in seven schools in a district in northern Uganda that is emerging from a twenty-year civil war. The curriculum of four primary schools, two secondary schools, one special school and one teacher training college was studied over a three-month period. A structure of knowledge, skills and values was used to research the framework at a detailed level. It is found that schools exhibit good socialization of reconciliation values and some development of problem-solving and communication skills. There is some understanding of human rights, but little knowledge of history, or of local, national and international political/legal systems. There is minimal development of discussion and critical thinking skills.
It is argued that the framework can be used to investigate other schools and to inform the design of a curriculum that can contribute to conflict transformation, with the ultimate aim of reducing the risk of civil war re-eruption
Cardiometabolic Pregnancy Complications in Association With Autism-Related Traits as Measured by the Social Responsiveness Scale in ECHO
Prior work has examined associations between cardiometabolic pregnancy complications and autism spectrum disorder (ASD) but not how these complications may relate to social communication traits more broadly. We addressed this question within the Environmental Inf luences on Child Health Outcomes program, with 6,778 participants from 40 cohorts conducted from 1998–2021 with information on ASD-related traits via the Social Responsiveness Scale. Four metabolic pregnancy complications were examined individually, and combined, in association with Social Responsiveness Scale scores, using crude and adjusted linear regression as well as quantile regression analyses. We also examined associations stratified by ASD diagnosis, and potential mediation by preterm birth and low birth weight, and modification by child sex and enriched risk of ASD. Increases in ASD-related traits were associated with obesity (β = 4.64, 95% confidence interval: 3.27, 6.01) and gestational diabetes (β = 5.21, 95% confidence interval: 2.41, 8.02), specifically, but not with hypertension or preeclampsia. Results among children without ASD were similar to main analyses, but weaker among ASD cases. There was not strong evidence for mediation or modification. Results suggest that common cardiometabolic pregnancy complications may inf luence child ASD-related traits, not only above a diagnostic threshold relevant to ASD but also across the population
New insights into the genetic etiology of Alzheimer's disease and related dementias
Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele
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