Examinando por Materia "Mammals"

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    Leptospirosis risk around a potential source of infection
    (SPIE-INT SOC OPTICAL ENGINEERING, 2015-01-01) Erica, Loaiza-Echeverry; Doracelly, Hincapie-Palacio; Acosta Jesus, Ochoa; Giraldo Juan, Ospina; Erica, Loaiza-Echeverry; Doracelly, Hincapie-Palacio; Acosta Jesus, Ochoa; Giraldo Juan, Ospina; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
    Leptospirosis is a bacterial zoonosis with world distribution and multiform clinical spectrum in men and animals. The etiology of this disease is the pathogenic species of Leptospira, which cause diverse manifestations of the disease, from mild to serious, such as the Weil disease and the lung hemorrhagic syndrome with lethal proportions of 10% - 50%. This is an emerging problem of urban health due to the growth of marginal neighborhoods without basic sanitary conditions and an increased number of rodents. The presence of rodents and the probability of having contact with their urine determine the likelihood for humans to get infected. In this paper, we simulate the spatial distribution of risk infection of human leptospirosis according to the proximity to rodent burrows considered as potential source of infection. The Bessel function K0 with an r distance from the potential point source, and the scale parameter a in meters was used. Simulation inputs were published data of leptospirosis incidence rate (range of 5 to 79 x 10 000), and a distance of 100 to 5000 meters from the source of infection. We obtained an adequate adjustment between the function and the simulated data. The risk of infection increases with the proximity of the potential source. This estimation can become a guide to propose effective measures of control and prevention. © 2015 SPIE.
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    Los enigmas del universo / Ernesto Haeckel ; traducción de Cristóbal Litrán
    (Valencia : F. Sempere y Ca. Editores, 1899) Haeckel, Ernst, 1834-1919; Litrán, Cristóbal, 1861-1926
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    Natural flexible armor as an inspirationfor body armor design
    (Soc. for the Advancement of Material and Process Engineering, 2015-05-21) Alexander Ossa, E.; Alexander Ossa, E.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    Animals have developed different strategies to protect themselves from environmental and predatory threats. One of these strategies concerns with the development of natural flexible dermal armor, usually consisting of rigid and highly mineralized units (e. g. scales or osteoderms) attached by flexible collagen fibers. These kinds of arrangements have been proven to achieve high flexibility without significant reduction in strength in comparison to monolithic structures. These are in fact features extremely valued by body armor users. This work studies the mechanical characteristics of scales and osteoderms of different animals (including mammals, reptiles and fishes), in order to compare them with other characteristics of the animal itself (like length and mobility) and characteristics of their predators like geometry and composition of their teeth and strength of bite. This comparison extends our knowledge and open new ways of understanding on how to design body armor materials and structures looking into improvements on flexibility and mobility. Copyright 2015. Used by the Society of the Advancement of Material and Process Engineering with permission.
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    Parameter estimation of a predator-prey model using a genetic algorithm
    (2010-01-01) Restrepo, J.G.; Sánchez, C.M.V.; Restrepo, J.G.; Sánchez, C.M.V.; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
    This paper presents the parameter estimation of a biological system with real data extracted from literature, and different model structures: Lotka-Volterra model (basic predator-prey model) and saturation predator-prey model. A third model is proposed and tested in simulation due to lack of appropriated real data; it includes inputs that excite the system and makes the estimation process more manageable. The model parameters were estimated using a genetic algorithm, which gives a combination of parameters used in simulation to compare outputs with real data and decide, using a cost function, which parameters are better. Comparing the models, the Lotka-Volterra model provides better adjustment but with unrealistic assumptions, while saturation model represents a system with real assumptions but the fit is not very high. ©2010 IEEE.
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    A Revision of Philander (Marsupialia: Didelphidae), Part 1: P. quica, P. canus, and a New Species from Amazonia
    (American Museum of Natural History, 2018-01-31) Voss, R.S.; Díaz-Nieto, J.F.; Jansa, S.A.; Universidad EAFIT. Departamento de Ciencias; Biodiversidad, Evolución y Conservación
    This is the first installment of a revision of the didelphid marsupial genus Philander, commonly known as gray four-eyed opossums. Although abundant and widespread in lowland tropical forests from southern Mexico to northern Argentina, species of Philander are not well understood taxonomically, and the current literature includes many examples of conflicting species definitions and nomenclatural usage. Our revision is based on coalescent analyses of mitochondrial gene sequences, phylogenetic analyses of mitochondrial and nuclear genes, morphometric analyses, and firsthand examination of relevant type material. Based on these results, we provisionally recognize eight species, of which three are formally treated in this report: P. quica (Temminck, 1824), an Atlantic Forest endemic formerly known as P. frenatus (Olfers, 1818); P. canus (Osgood, 1913), a widespread species formerly treated as a synonym or subspecies of P. opossum (Linnaeus, 1758); and P. pebas, a new species endemic to Amazonia. The remaining, possibly valid, species of Philander can be allocated to two clades. The first is a cis-Andean complex that includes P. andersoni (Osgood, 1913); P. mcilhennyi Gardner and Patton, 1972; and P. opossum. The second is a trans-Andean complex that includes P. melanurus (Thomas, 1899) and P. pallidus (Allen, 1901). Among other nomenclatural acts, we designate a neotype for the long-problematic nominal taxon Didelphis superciliaris Olfers, 1818, and (in an appendix coauthored by Renate Angermann), we establish that Olfers' coeval binomen D. frenata is based on an eastern Amazonian type and is a junior synonym of P. opossum. © American Museum of Natural History 2018.
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    A REVISION OF THE DIDELPHID MARSUPIAL GENUS MARMOSA PART 2. SPECIES OF THE RAPPOSA GROUP (SUBGENUS MICOUREUS)
    (AMER MUSEUM NATURAL HISTORY, 2020-06-01) Voss, Robert S.; Giarla, Thomas C.; Diaz-Nieto, Juan F.; Jansa, Sharon A.; Universidad EAFIT. Departamento de Ciencias; Biodiversidad, Evolución y Conservación
    In this report, the second of a revisionary series on mouse opossums (Marmosa), we analyze cytochrome b sequence data from 166 specimens of the subgenus Micoureus and delimit putative species using the multirate Poisson Tree Processes (mPTP) method. That analysis identifies 21 putative species, many of which can be matched with available names, including alstoni, constantiae, demerarae, limae, germana, meridae, paraguayana, parda, perplexa, phaea, rapposa, and rutteri. However, some of these nominal taxa are not morphologically diagnosable, and in the absence of other corroborating evidence, we do not recommend that they all be recognized as valid. Phylogenetic analyses of a multigene dataset suggest that putative species of Micoureus belong to several wellsupported clades, one of which (the ``Rapposa Group'') is revised in this report. As defined herein, the Rapposa Group includes at least three valid species: M. rapposa Thomas, 1899 (including budini Thomas, 1920); M. parda Tate, 1931; and M. rutteri Thomas, 1924. Herein we document their ecogeographic distributions and diagnostic traits, comment on their taxonomic histories, and list the specimens we examined (including all relevant type material).