974 resultados para Taxonomic impediment
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Phylogenetic relationships within the Tabanidae are largely unknown, despite their considerable medical and ecological importance. The first robust phylogenetic hypothesis for the horse fly tribe Scionini is provided, completing the systematic placement of all tribes in the subfamily Pangoniinae. The Scionini consists of seven mostly southern hemisphere genera distributed in Australia, New Guinea, New Zealand and South America. A 5757. bp alignment of 6 genes, including mitochondrial (COI and COII), ribosomal (28S) and nuclear (AATS and CAD regions 1, 3 and 4) genes, was analysed for 176 taxa using both Bayesian and maximum likelihood approaches. Results indicate the Scionini are strongly monophyletic, with the exclusion of the only northern hemisphere genus Goniops. The South American genera Fidena, Pityocera and Scione were strongly monophyletic, corresponding to current morphology-based classification schemes. The most widespread genus Scaptia was paraphyletic and formed nine strongly supported monophyletic clades, each corresponding to either the current subgenera or several previously synonymised genera that should be formally resurrected. Molecular results also reveal a newly recognised genus endemic to New Zealand, formerly placed within Scaptia. Divergence time estimation was employed to assess the global biogeographical patterns in the Pangoniinae. These analyses demonstrated that the Scionini are a typical Gondwanan group whose diversification was influenced by the fragmentation of that ancient land mass. Furthermore, results indicate that the Scionini most likely originated in Australia and subsequently radiated to New Zealand and South American by both long distance dispersal and vicariance. The phylogenetic framework of the Scionini provided herein will be valuable for taxonomic revisions of the Tabanidae.
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Bactrocera dorsalis (Hendel), Bactrocera papayae Drew & Hancock, Bactrocera philippinensis Drew & Hancock, and Bactrocera carambolae Drew & Hancock are pest members within the B. dorsalis species complex of tropical fruit flies. The species status of these taxa is unclear and this confounds quarantine, pest management, and general research. Mating studies carried out under uniform experimental conditions are required as part of resolving their species limits. These four taxa were collected from the wild and established as laboratory cultures for which we subsequently determined levels of prezygotic compatibility, assessed by field cage mating trials for all pair-wise combinations. We demonstrate random mating among all pair-wise combinations involving B. dorsalis, B. papayae, and B. philippinensis. B. carambolae was relatively incompatible with each of these species as evidenced by nonrandom mating for all crosses. Reasons for incompatibility involving B. carambolae remain unclear; however, we observed differences in the location of couples in the field cage for some comparisons. Alongside other factors such as pheromone composition or other courtship signals, this may lead to reduced interspecific mating compatibility with B. carambolae. These data add to evidence that B. dorsalis, B. papayae, and B. philippinensis represent the same biological species, while B. carambolae remains sufficiently different to maintain its current taxonomic identity. This poses significant implications for this group's systematics, impacting on pest management, and international trade.
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The invasive liana cat’s claw creeper Dolichandra unguis-cati (L.) L.G. Lohmann (syn. Macfadyena unguis-cati (L.) A.H. Gentry) exhibits intraspecific variation in leaf morphology, but this is rarely noted in the published literature. The present study documents variation in leaf morphology in two forms of the species that occur in Australia (long pod and short pod). Leaf morphology is compared between the two forms and the position of the shoots (trunk and ground) at the only two sites in which they co-occur. Leaves were categorised on the basis of leaflet number and the presence or absence of tendrils. Simple leaves were produced mainly on shoots growing along the ground and were more abundant in the short-pod form. Long-pod plants were dominated by bifoliate leaves with tendrils. Cat’s claw creeper exhibits considerably wider variation in leaf morphology than recorded previously. Variations in leaf morphology may be linked to differences in the genotype, developmental stage and plastic responses of the plants. Understanding these variations may have implications for taxonomic delimitation and improved management, particularly biological control involving leaf-feeding insects.
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Post-transplantation lymphoproliferative disorders (PTLD) arise in the immunosuppressed and are frequently Epstein-Barr virus (EBV) associated. The most common PTLD histological sub-type is diffuse large B-cell lymphoma (EBV+DLBCL-PTLD). Restoration of EBV-specific T-cell immunity can induce EBV+DLBCL-PTLD regression. The most frequent B-cell lymphoma in the immunocompetent is also DLBCL. ‘EBV-positive DLBCL of the elderly’ (EBV+DLBCL) is a rare but well-recognized DLBCL entity that occurs in the overtly immunocompetent, that has an adverse outcome relative to EBV-negative DLBCL. Unlike PTLD (which is classified as viral latency III), literature suggests EBV+DLBCL is typically latency II, i.e. expression is limited to the immuno-subdominant EBNA1, LMP1 and LMP2 EBV-proteins. If correct, this would be a major impediment for T-cell immunotherapeutic strategies. Unexpectedly we observed EBV+DLBCL-PTLD and EBV+DLBCL both shared features consistent with type III EBV-latency, including expression of the immuno-dominant EBNA3A protein. Extensive analysis showed frequent polymorphisms in EBNA1 and LMP1 functionally defined CD8+ T-cell epitope encoding regions, whereas EBNA3A polymorphisms were very rare making this an attractive immunotherapy target. As with EBV+DLBCL-PTLD, the antigen presenting machinery within lymphomatous nodes was intact. EBV+DLBCL express EBNA3A suggesting it is amenable to immunotherapeutic strategies.
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1. Expert knowledge continues to gain recognition as a valuable source of information in a wide range of research applications. Despite recent advances in defining expert knowledge, comparatively little attention has been given to how to view expertise as a system of interacting contributory factors, and thereby, to quantify an individual’s expertise. 2. We present a systems approach to describing expertise that accounts for many contributing factors and their interrelationships, and allows quantification of an individual’s expertise. A Bayesian network (BN) was chosen for this purpose. For the purpose of illustration, we focused on taxonomic expertise. The model structure was developed in consultation with professional taxonomists. The relative importance of the factors within the network were determined by a second set of senior taxonomists. This second set of experts (i.e. supra-experts) also provided validation of the model structure. Model performance was then assessed by applying the model to hypothetical career states in the discipline of taxonomy. Hypothetical career states were used to incorporate the greatest possible differences in career states and provide an opportunity to test the model against known inputs. 3. The resulting BN model consisted of 18 primary nodes feeding through one to three higher-order nodes before converging on the target node (Taxonomic Expert). There was strong consistency among node weights provided by the supra-experts for some nodes, but not others. The higher order nodes, “Quality of work” and “Total productivity”, had the greatest weights. Sensitivity analysis indicated that although some factors had stronger influence in the outer nodes of the network, there was relatively equal influence of the factors leading directly into the target node. Despite differences in the node weights provided by our supra-experts, there was remarkably good agreement among assessments of our hypothetical experts that accurately reflected differences we had built into them. 4. This systems approach provides a novel way of assessing the overall level of expertise of individuals, accounting for multiple contributory factors, and their interactions. Our approach is adaptable to other situations where it is desirable to understand components of expertise.
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Acoustic sensors are increasingly used to monitor biodiversity. They can remain deployed in the environment for extended periods to passively and objectively record the sounds of the environment. The collected acoustic data must be analyzed to identify the presence of the sounds made by fauna in order to understand biodiversity. Citizen scientists play an important role in analyzing this data by annotating calls and identifying species. This paper presents our research into bioacoustic annotation techniques. It describes our work in defining a process for managing, creating, and using tags that are applied to our annotations. This paper includes a detailed description of our methodology for correcting and then linking our folksonomic tags to taxonomic data sources. Providing tools and processes for maintaining species naming consistency is critical to the success of a project designed to generate scientific data. We demonstrate that cleaning the folksonomic data and providing links to external taxonomic authorities enhances the scientific utility of the tagging efforts of citizen scientists.
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The practical need to partition the world of viruses into distinguishable, universally agreed upon entities is the ultimate justification for developing a virus classification system. The Author of this Book is Andrew MQ King, Elliot Lefkowitz, Eric B. Carstens, Michael J. Adams Since 1971, the International Committee on Taxonomy of Viruses (ICTV) operating on behalf of the world community of virologists has taken on the task of developing a single, universal taxonomic scheme for all viruses infecting animals (vertebrate, invertebrates, and protozoa), plants (higher plants and algae), fungi, bacteria, and archaea.
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We provide a taxonomic redescription of the Fawn Antechinus, Antechinus bellus (Thomas). A. bellus is the only member of its genus to occur in Australia’s Northern Territory, where it can be found in savannah woodlands of the Top End. It is perhaps the most distinctive antechinus, and clearly distinguishable from the other 10 extant species of antechinus found in Australia: externally, A. bellus has pale body fur, white feet and large ears; A. bellus skulls have large auditory bullae and narrow interorbital width, while broadening abruptly at the molar row; mitochondrial and nuclear genes clearly dis-tinguish A. bellus from all congeners, phylogenetically positioning the Fawn Antechinus as sister to Queensland’s A. leo Van Dyck, 1980, with which it shares a curled supratragus of the external ear and a similar tropical latitudinal range.
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We provide a taxonomic redescription of the ubiquitous and variable dasyurid marsupial Yellow-footed Antechinus, Antechinus flavipes (Waterhouse), which comprises three currently recognized subspecies whose combined geographic distribution spans almost the length and breadth of Australia. A. flavipes leucogaster Gray is confined to south-west Western Australia; A. flavipes flavipes is distributed in south-eastern Australia across four states—South Australia, Victoria, New South Wales and Queensland; A. flavipes rubeculus Van Dyck is confined to the wet tropics of Queensland. A. flavipes is readily distinguished from all extant congeners based on external morphology by the following combination of features: a grey head; orange-yellow toned flanks/rump, feet and tail base; pale eye-rings and a darkened tail tip. A. flavipes skulls are stout, being broad at the level of the rear upper molars, have small palatal vacuities and small entoconid cusps on the lower molars. However, notable differences among subspecies of A. flavipesprevent any obvious collection of skull characters being diagnostic for species-level discrimination among congeners. A. flavipes rubeculus is the largest of the three subspecies of Yellow-footed Antechinus and most similar in skull morphology to A. leo, A. bellus and A. godmani—all four species are geographically limited to tropical Australia. A. f. rubeculus is notably larger in many characters than its conspecifics: A. f. flavipes, the next largest, and A. f. leucogaster, the smallest of the group. A. f. flavipes and A. f. leucogaster diverge significantly at only a few skull characters, and both subspecies have cranial morphological affinities with the recently discovered A. mysticus, most notably A. f. leucogaster. Phylogenies generated from mt- and nDNA data strongly support Antechinus flavipes as monophyletic with respect to other members of the genus; within A. flavipes, each of the three recognized subspecies form distinctive monophyletic clades.
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We provide a taxonomic redescription of the dasyurid marsupial Atherton Antechinus, Antechinus godmani (Thomas). A. godmani is only rarely encountered and limited to wet tropical rainforests of north-east Queensland, Australia, between the towns of Cardwell and Cairns (a distribution spanning 135 kilometres from north to south). The distinctive species occurs at altitudes of over 600 meters asl, in all major rainforest types, and can be found with both the northern subspecies of the Yellow-footed Antechinus, A. flavipes rubeculus Van Dyck and the Rusty Antechinus, A. adustus (Thomas). A. god-mani is clearly separated from all congeners on the basis of both morphometrics and genetics. A. godmani can be distin-guished from all extant congeners based on external morphology by a combination of large size, naked-looking tail and reddish fur on the face and head. A. godmani skulls are characteristically large, with a suite of long features: basicranium, palate, upper premolar tooth row, inter-palatal vacuity distance and dentary. Phylogenies generated from mt- and nDNA data position Antechinus godmani as monophyletic with respect to other members of the genus; A. godmani is strongly supported as the sister-group to a clade containing all other antechinus, but excluding the south-east Australian Dusky An-techinus, A. swainsonii (Waterhouse) and Swamp Antechinus, A. minimus (Geoffroy). Antechinus godmani are genetically very divergent compared to all congeners (mtDNA: range 12.9–16.3%).
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Most recommender systems attempt to use collaborative filtering, content-based filtering or hybrid approach to recommend items to new users. Collaborative filtering recommends items to new users based on their similar neighbours, and content-based filtering approach tries to recommend items that are similar to new users' profiles. The fundamental issues include how to profile new users, and how to deal with the over-specialization in content-based recommender systems. Indeed, the terms used to describe items can be formed as a concept hierarchy. Therefore, we aim to describe user profiles or information needs by using concepts vectors. This paper presents a new method to acquire user information needs, which allows new users to describe their preferences on a concept hierarchy rather than rating items. It also develops a new ranking function to recommend items to new users based on their information needs. The proposed approach is evaluated on Amazon book datasets. The experimental results demonstrate that the proposed approach can largely improve the effectiveness of recommender systems.
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Many mature term-based or pattern-based approaches have been used in the field of information filtering to generate users’ information needs from a collection of documents. A fundamental assumption for these approaches is that the documents in the collection are all about one topic. However, in reality users’ interests can be diverse and the documents in the collection often involve multiple topics. Topic modelling, such as Latent Dirichlet Allocation (LDA), was proposed to generate statistical models to represent multiple topics in a collection of documents, and this has been widely utilized in the fields of machine learning and information retrieval, etc. But its effectiveness in information filtering has not been so well explored. Patterns are always thought to be more discriminative than single terms for describing documents. However, the enormous amount of discovered patterns hinder them from being effectively and efficiently used in real applications, therefore, selection of the most discriminative and representative patterns from the huge amount of discovered patterns becomes crucial. To deal with the above mentioned limitations and problems, in this paper, a novel information filtering model, Maximum matched Pattern-based Topic Model (MPBTM), is proposed. The main distinctive features of the proposed model include: (1) user information needs are generated in terms of multiple topics; (2) each topic is represented by patterns; (3) patterns are generated from topic models and are organized in terms of their statistical and taxonomic features, and; (4) the most discriminative and representative patterns, called Maximum Matched Patterns, are proposed to estimate the document relevance to the user’s information needs in order to filter out irrelevant documents. Extensive experiments are conducted to evaluate the effectiveness of the proposed model by using the TREC data collection Reuters Corpus Volume 1. The results show that the proposed model significantly outperforms both state-of-the-art term-based models and pattern-based models
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Sorghum is a food and feed cereal crop adapted to heat and drought and a staple for 500 million of the world’s poorest people. Its small diploid genome and phenotypic diversity make it an ideal C4 grass model as a complement to C3 rice. Here we present high coverage (16–45 × ) resequenced genomes of 44 sorghum lines representing the primary gene pool and spanning dimensions of geographic origin, end-use and taxonomic group. We also report the first resequenced genome of S. propinquum, identifying 8 M high-quality SNPs, 1.9 M indels and specific gene loss and gain events in S. bicolor. We observe strong racial structure and a complex domestication history involving at least two distinct domestication events. These assembled genomes enable the leveraging of existing cereal functional genomics data against the novel diversity available in sorghum, providing an unmatched resource for the genetic improvement of sorghum and other grass species.
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We describe a new species of dasyurid marsupial within the genus Antechinus that was previously known as a northern outlier of Dusky Antechinus (A. swainsonii). The Black-tailed Antechinus, Antechinus arktos sp. nov., is known only from areas of high altitude and high rainfall on the Tweed Volcano caldera of far south-east Queensland and north-east New South Wales, Australia. Antechinus arktos formerly sheltered under the taxonomic umbrella of A. swainsonii mimetes, the widespread mainland form of Dusky Antechinus. With the benefit of genetic hindsight, some striking morphological differences are herein resolved: A. s. mimetes is more uniformly deep brown-black to grizzled grey-brown from head to rump, with brownish (clove brown—raw umber) hair on the upper surface of the hindfoot and tail, whereas A. arktos is more vibrantly coloured, with a marked change from greyish-brown head to orange-brown rump, fuscous black on the upper surface of the hindfoot and dense, short fur on the evenly black tail. Further, A. arktos has marked orange-brown fur on the upper and lower eyelid, cheek and in front of the ear and very long guard hairs all over the body; these characters are more subtle in A. s. mimetes. There are striking genetic differences between the two species: at mtDNA, A. s. mimetes from north-east New South Wales is 10% divergent to A. arktos from its type locality at Springbrook NP, Queensland. In contrast, the Ebor A. s. mimetes clades closely with conspecifics from ACT and Victoria. A. arktos skulls are strikingly different to all subspecies of A. swainsonii. A. arktos are markedly larger than A. s. mimetes and A. s. swainsonii (Tasmania) for a range of craniodental measures. Antechinus arktos were historically found at a few proximate mountainous sites in south-east Queensland, and have only recently been recorded from or near the type locality. Even there, the species is likely in low abundance. The Black-tailed Antechinus has plausibly been detrimentally affected by climate change in recent decades, and will be at further risk with increasing warming trends.
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The mitochondrial (mt) genome is, to date, the most extensively studied genomic system in insects, outnumbering nuclear genomes tenfold and representing all orders versus very few. Phylogenomic analysis methods have been tested extensively, identifying compositional bias and rate variation, both within and between lineages, as the principal issues confronting accurate analyses. Major studies at both inter- and intraordinal levels have contributed to our understanding of phylogenetic relationships within many groups. Genome rearrangements are an additional data type for defining relationships, with rearrangement synapomorphies identified across multiple orders and at many different taxonomic levels. Hymenoptera and Psocodea have greatly elevated rates of rearrangement offering both opportunities and pitfalls for identifying rearrangement synapomorphies in each group. Finally, insects are model systems for studying aberrant mt genomes, including truncated tRNAs and multichromosomal genomes. Greater integration of nuclear and mt genomic studies is necessary to further our understanding of insect genomic evolution.