77 research outputs found
Neural hypernetwork approach for pulmonary embolism diagnosis
Background
Hypernetworks are based on topological simplicial complexes and generalize the concept of two-body relation to many-body relation. Furthermore, Hypernetworks provide a significant generalization of network theory, enabling the integration of relational structure, logic and analytic dynamics. A pulmonary embolism is a blockage of the main artery of the lung or one of its branches, frequently fatal.
Results
Our study uses data on 28 diagnostic features of 1427 people considered to be at risk of pulmonary embolism enrolled in the Department of Internal and Subintensive Medicine of an Italian National Hospital “Ospedali Riuniti di Ancona”. Patients arrived in the department after a first screening executed by the emergency room. The resulting neural hypernetwork correctly recognized 94 % of those developing pulmonary embolism. This is better than previous results obtained with other methods (statistical selection of features, partial least squares regression, topological data analysis in a metric space).
Conclusion
In this work we successfully derived a new integrative approach for the analysis of partial and incomplete datasets that is based on Q-analysis with machine learning. The new approach, called Neural Hypernetwork, has been applied to a case study of pulmonary embolism diagnosis. The novelty of this method is that it does not use clinical parameters extracted by imaging analysis
Genetic Diversity and Population Parameters of Sea Otters, Enhydra lutris, before Fur Trade Extirpation from 1741–1911
All existing sea otter, Enhydra lutris, populations have suffered at least one historic population bottleneck stemming from the fur trade extirpations of the eighteenth and nineteenth centuries. We examined genetic variation, gene flow, and population structure at five microsatellite loci in samples from five pre-fur trade populations throughout the sea otter's historical range: California, Oregon, Washington, Alaska, and Russia. We then compared those values to genetic diversity and population structure found within five modern sea otter populations throughout their current range: California, Prince William Sound, Amchitka Island, Southeast Alaska and Washington. We found twice the genetic diversity in the pre-fur trade populations when compared to modern sea otters, a level of diversity that was similar to levels that are found in other mammal populations that have not experienced population bottlenecks. Even with the significant loss in genetic diversity modern sea otters have retained historical structure. There was greater gene flow before extirpation than that found among modern sea otter populations but the difference was not statistically significant. The most dramatic effect of pre fur trade population extirpation was the loss of genetic diversity. For long term conservation of these populations increasing gene flow and the maintenance of remnant genetic diversity should be encouraged
The mammals of Angola
Scientific investigations on the mammals of Angola started over 150 years
ago, but information remains scarce and scattered, with only one recent published
account. Here we provide a synthesis of the mammals of Angola based on a thorough
survey of primary and grey literature, as well as recent unpublished records. We present
a short history of mammal research, and provide brief information on each species
known to occur in the country. Particular attention is given to endemic and near endemic
species. We also provide a zoogeographic outline and information on the conservation
of Angolan mammals. We found confirmed records for 291 native species, most of
which from the orders Rodentia (85), Chiroptera (73), Carnivora (39), and
Cetartiodactyla (33). There is a large number of endemic and near endemic species,
most of which are rodents or bats. The large diversity of species is favoured by the wide range of habitats with contrasting environmental conditions, while endemism tends to
be associated with unique physiographic settings such as the Angolan Escarpment. The
mammal fauna of Angola includes 2 Critically Endangered, 2 Endangered, 11
Vulnerable, and 14 Near-Threatened species at the global scale. There are also 12 data
deficient species, most of which are endemics or near endemics to the countryinfo:eu-repo/semantics/publishedVersio
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