457 research outputs found
Mapping Physiological Suitability Limits for Malaria in Africa Under Climate Change
We mapped current and future temperature suitability for malaria
transmission in Africa using a published model that incorporates
nonlinear physiological responses to temperature of the mosquito
vector Anopheles gambiae and the malaria parasite Plasmodium
falciparum. We found that a larger area of Africa currently
experiences the ideal temperature for transmission than
previously supposed. Under future climate projections, we
predicted a modest increase in the overall area suitable for
malaria transmission, but a net decrease in the most suitable
area. Combined with human population density projections, our
maps suggest that areas with temperatures suitable for
year-round, highest-risk transmission will shift from coastal
West Africa to the Albertine Rift between the Democratic
Republic of Congo and Uganda, whereas areas with seasonal
transmission suitability will shift toward sub-Saharan coastal
areas. Mapping temperature suitability places important bounds
on malaria transmissibility and, along with local level
demographic, socioeconomic, and ecological factors, can indicate
where resources may be best spent on malaria control
Understanding uncertainty in temperature effects on vector-borne disease: A Bayesian approach
Extrinsic environmental factors influence the distribution and population
dynamics of many organisms, including insects that are of concern for human
health and agriculture. This is particularly true for vector-borne infectious
diseases, like malaria, which is a major source of morbidity and mortality in
humans. Understanding the mechanistic links between environment and population
processes for these diseases is key to predicting the consequences of climate
change on transmission and for developing effective interventions. An important
measure of the intensity of disease transmission is the reproductive number
. However, understanding the mechanisms linking and temperature, an
environmental factor driving disease risk, can be challenging because the data
available for parameterization are often poor. To address this we show how a
Bayesian approach can help identify critical uncertainties in components of
and how this uncertainty is propagated into the estimate of . Most
notably, we find that different parameters dominate the uncertainty at
different temperature regimes: bite rate from 15-25 C; fecundity across
all temperatures, but especially 25-32 C; mortality from
20-30 C; parasite development rate at 15-16C and again at
33-35C. Focusing empirical studies on these parameters and
corresponding temperature ranges would be the most efficient way to improve
estimates of . While we focus on malaria, our methods apply to improving
process-based models more generally, including epidemiological, physiological
niche, and species distribution models.Comment: 27 pages, including 1 table and 3 figure
Managed Aquifer Recharge as a Tool to Enhance Sustainable Groundwater Management in California
A growing population and an increased demand for water resources have resulted in a global trend of groundwater depletion. Arid and semi-arid climates are particularly susceptible, often relying on groundwater to support large population centers or irrigated agriculture in the absence of sufficient surface water resources. In an effort to increase the security of groundwater resources, managed aquifer recharge (MAR) programs have been developed and implemented globally. MAR is the approach of intentionally harvesting and infiltrating water to recharge depleted aquifer storage. California is a prime example of this growing problem, with three cities that have over a million residents and an agricultural industry that was valued at 47 billion dollars in 2015. The present-day groundwater overdraft of over 100 km3 (since 1962) indicates a clear disparity between surface water supply and water demand within the state. In the face of groundwater overdraft and the anticipated effects of climate change, many new MAR projects are being constructed or investigated throughout California, adding to those that have existed for decades. Some common MAR types utilized in California include injection wells, infiltration basins (also known as spreading basins, percolation basins, or recharge basins), and low-impact development. An emerging MAR type that is actively being investigated is the winter flooding of agricultural fields using existing irrigation infrastructure and excess surface water resources, known as agricultural MAR. California therefore provides an excellent case study to look at the historical use and performance of MAR, ongoing and emerging challenges, novel MAR applications, and the potential for expansion of MAR. Effective MAR projects are an essential tool for increasing groundwater security, both in California and on a global scale. This chapter aims to provide an overview of the most common MAR types and applications within the State of California and neighboring semi-arid regions
A chromosome-scale high-contiguity genome assembly of the cheetah (Acinonyx jubatus)
AbstractThe cheetah (Acinonyx jubatus, SCHREBER 1775) is a large felid and is considered the fastest land animal. Historically, it inhabited open grassland across Africa, the Arabian Peninsula, and southwestern Asia; however, only small and fragmented populations remain today. Here, we present a de novo genome assembly of the cheetah based on PacBio continuous long reads and Hi-C proximity ligation data. The final assembly (VMU_Ajub_asm_v1.0) has a total length of 2.38 Gb, of which 99.7% are anchored into the expected 19 chromosome-scale scaffolds. The contig and scaffold N50 values of 96.8 Mb and 144.4 Mb, respectively, a BUSCO completeness of 95.4% and a k-mer completeness of 98.4%, emphasize the high quality of the assembly. Furthermore, annotation of the assembly identified 23,622 genes and a repeat content of 40.4%. This new highly contiguous and chromosome-scale assembly will greatly benefit conservation and evolutionary genomic analyses and will be a valuable resource, e.g., to gain a detailed understanding of the function and diversity of immune response genes in felids.Abstract
The cheetah (Acinonyx jubatus, SCHREBER 1775) is a large felid and is considered the fastest land animal. Historically, it inhabited open grassland across Africa, the Arabian Peninsula, and southwestern Asia; however, only small and fragmented populations remain today. Here, we present a de novo genome assembly of the cheetah based on PacBio continuous long reads and Hi-C proximity ligation data. The final assembly (VMU_Ajub_asm_v1.0) has a total length of 2.38 Gb, of which 99.7% are anchored into the expected 19 chromosome-scale scaffolds. The contig and scaffold N50 values of 96.8 Mb and 144.4 Mb, respectively, a BUSCO completeness of 95.4% and a k-mer completeness of 98.4%, emphasize the high quality of the assembly. Furthermore, annotation of the assembly identified 23,622 genes and a repeat content of 40.4%. This new highly contiguous and chromosome-scale assembly will greatly benefit conservation and evolutionary genomic analyses and will be a valuable resource, e.g., to gain a detailed understanding of the function and diversity of immune response genes in felids
Role of monocarboxylate transporters in human cancers : state of the art
Monocarboxylate transporters (MCTs) belong to the SLC16 gene family, presently composed by 14 members. MCT1-MCT4 are proton symporters, which mediate the transmembrane transport of pyruvate, lactate and ketone bodies. The role of MCTs in cell homeostasis has been characterized in detail in normal tissues, however, their role in cancer is still far from understood. Most solid tumors are known to rely on glycolysis for energy production and this activity leads to production of important amounts of lactate, which are exported into the extracellular milieu, contributing to the acidic microenvironment. In this context, MCTs will play a dual role in the maintenance of the hyper-glycolytic acidresistant phenotype of cancer, allowing the maintenance of the high glycolytic rates by performing lactate efflux, and pH regulation by the co-transport of protons. Thus, they constitute attractive targets for cancer therapy, which have been little explored. Here we review the literature on the role of MCTs in solid tumors in different locations, such as colon, central nervous system, breast, lung, gynecologic tract, prostate, stomach, however, there are many conflicting results and in most cases there are no functional studies showing the dependence of the tumors on MCT expression and activity. Additional studies on MCT expression in other tumor types, confirmation of the results already published as well as additional functional studies are needed to deeply understand the role of MCTs in cancer maintenance and aggressiveness
Improving Illumina assemblies with Hi-C and long reads : An example with the North African dromedary
Researchers have assembled thousands of eukaryotic genomes using Illumina reads, but traditional mate-pair libraries cannot span all repetitive elements, resulting in highly fragmented assemblies. However, both chromosome conformation capture techniques, such as Hi-C and Dovetail Genomics Chicago libraries and long-read sequencing, such as Pacific Biosciences and Oxford Nanopore, help span and resolve repetitive regions and therefore improve genome assemblies. One important livestock species of arid regions that does not have a high-quality contiguous reference genome is the dromedary (Camelus dromedarius). Draft genomes exist but are highly fragmented, and a high-quality reference genome is needed to understand adaptation to desert environments and artificial selection during domestication. Dromedaries are among the last livestock species to have been domesticated, and together with wild and domestic Bactrian camels, they are the only representatives of the Camelini tribe, which highlights their evolutionary significance. Here we describe our efforts to improve the North African dromedary genome. We used Chicago and Hi-C sequencing libraries from Dovetail Genomics to resolve the order of previously assembled contigs, producing almost chromosome-level scaffolds. Remaining gaps were filled with Pacific Biosciences long reads, and then scaffolds were comparatively mapped to chromosomes. Long reads added 99.32 Mbp to the total length of the new assembly. Dovetail Chicago and Hi-C libraries increased the longest scaffold over 12-fold, from 9.71 Mbp to 124.99 Mbp and the scaffold N50 over 50-fold, from 1.48 Mbp to 75.02 Mbp. We demonstrate that Illumina de novo assemblies can be substantially upgraded by combining chromosome conformation capture and long-read sequencing.Peer reviewe
Dialogue and materiality/embodiment in science|arts creative pedagogy: their role and manifestation
This is the final version. Available on open access from Elsevier via the DOI in this record.This paper responds to recent calls to explore the nuances of the interaction between the sciences, the arts and their inherent creativity to better understand their potential within teaching and learning. Building on previous arguments that the science-arts-creativity relationship is dialogic and relational, this research focuses on the question: How are dialogue and material/embodied activity manifested within creative pedagogy? We begin with a fusion of Bakhtinian-inspired and New-Materialist understandings of dialogue drawing out the importance of embodiment in order to revitalize how we articulate dialogue within creative educational practice. We then take on the challenge of a materialist diffractive analysis to conduct research which complements the theoretical framing and offers our outcomes in a way that appropriately makes the phenomena tangible. We present the outcomes of the diffractive analysis including the constitution of matter as well as meaning in the dialogic space; and the emergence of new assemblages of embodied teachers, students, ideas, and objects within transdisciplinary educational practice. We conclude by arguing for the benefits of diffractive analysis: that we have fore-fronted the entangled relationality of trans-disciplinary creative pedagogy; avoided bracketing out aspects of education that are often side-lined; opened out the space of pedagogical
approaches that might be attempted; and begun to challenge what education is for. In so doing, the article aims to open up new ways for teachers, students and researchers to experience seeing, doing, feeling and researching science|arts creative pedagogy and provoke conversations about how this might develop in the future.European Commissio
The major histocompatibility complex in Old World camelids and low polymorphism of its class II genes
BACKGROUND: The Major Histocompatibility Complex (MHC) is a genomic region containing genes with crucial roles in immune responses. MHC class I and class II genes encode antigen-presenting molecules expressed on the cell surface. To counteract the high variability of pathogens, the MHC evolved into a region of considerable heterogeneity in its organization, number and extent of polymorphism. Studies of MHCs in different model species contribute to our understanding of mechanisms of immunity, diseases and their evolution. Camels are economically important domestic animals and interesting biomodels. Three species of Old World camels have been recognized: the dromedary (Camelus dromedarius), Bactrian camel (Camelus bactrianus) and the wild camel (Camelus ferus). Despite their importance, little is known about the MHC genomic region, its organization and diversity in camels. The objectives of this study were to identify, map and characterize the MHC region of Old World camelids, with special attention to genetic variation at selected class MHC II loci. RESULTS: Physical mapping located the MHC region to the chromosome 20 in Camelus dromedarius. Cytogenetic and comparative analyses of whole genome sequences showed that the order of the three major sub-regions is “Centromere - Class II – Class III – Class I”. DRA, DRB, DQA and DQB exon 2 sequences encoding the antigen binding site of the corresponding class II antigen presenting molecules showed high degree of sequence similarity and extensive allele sharing across the three species. Unexpectedly low extent of polymorphism with low numbers of alleles and haplotypes was observed in all species, despite different geographic origins of the camels analyzed. The DRA locus was found to be polymorphic, with three alleles shared by all three species. DRA and DQA sequences retrieved from ancient DNA samples of Camelus dromedarius suggested that additional polymorphism might exist. CONCLUSIONS: This study provided evidence that camels possess an MHC comparable to other mammalian species in terms of its genomic localization, organization and sequence similarity. We described ancient variation at the DRA locus, monomorphic in most species. The extent of molecular diversity of MHC class II genes seems to be substantially lower in Old World camels than in other mammalian species. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12864-016-2500-1) contains supplementary material, which is available to authorized users
The potential and shortcomings of mitochondrial DNA analysis for cheetah conservation management
There are only about 7,100 adolescent and adult cheetahs (Acinonyx jubatus) remaining in the wild. With the majority occurring outside protected areas, their numbers are rapidly declining. Evidence-based conservation measures are essential for the survival of this species. Genetic data is routinely used to inform conservation strategies, e.g., by establishing conservation units (CU). A commonly used marker in conservation genetics is mitochondrial DNA (mtDNA). Here, we investigated the cheetah’s phylogeography using a large-scale mtDNA data set to refine subspecies distributions and better assign individuals to CUs. Our dataset mostly consisted of historic samples to cover the cheetah’s whole range as the species has been extinct in most of its former distribution. While our genetic data largely agree with geography-based subspecies assignments, several geographic regions show conflicting mtDNA signals. Our analyses support previous findings that evolutionary forces such as incomplete lineage sorting or mitochondrial capture likely confound the mitochondrial phylogeography of this species, especially in East and, to some extent, in Northeast Africa. We caution that subspecies assignments solely based on mtDNA should be treated carefully and argue for an additional standardized nuclear single nucleotide polymorphism (SNP) marker set for subspecies identification and monitoring. However, the detection of the A. j. soemmeringii specific haplogroup by a newly designed Amplification-Refractory Mutation System (ARMS) can already provide support for conservation measures.info:eu-repo/semantics/publishedVersio
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