Examinando por Materia "Canada"

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    Ítem
    Bases para la modelación de epidemias: El caso del síndrome respiratorio agudo severo en Canadá
    (Universidad Nacional de Colombia, 2007-01-01) Hincapié, D.; Ospina, J.; Hincapié, D.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
    Objective: Severe acute respiratory syndrome propagation in Canada during 2003 is analysed by means of simple models, comparing the influence of isolation measures on two epidemic waves. Methods: Deterministic susceptible-infected and susceptible-infected-removed models were used for both epidemic waves, using official published information. NLREG 6.2 was used for estimating deterministic parameters and analytical solutions were obtained with Maple 9 software. Dynamical indicators were obtained for the epidemic. Results: Suitable adjustment of the data was observed with both models, but smaller adjustment was observed during the second wave with the non- removed model. The highest rate of infectiousness was shown (35 new cases per 10 000 susceptible people) during the second wave (with R0 near to one), in spite of presenting greater incidence (8.8 cases per day), compensated for by a high rate of removal (11,5 cases per day) which lasted less than the epidemic (11,1 days), and a lower rate of attack (1 case per each 100 susceptible people). Conclusions: The susceptible-infected model can be useful during an epidemic's initial phase (prior to removal); however, closer monitoring of an epidemic's development is required for modelling the strength of removal and deriving useful information for decision-making.
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    Ítem
    Evolution of Sandspits Along the Caribbean Coast of Colombia: Natural and Human Influences
    (SPRINGER-VERLAG BERLIN, 2015-01-01) Anfuso, G.; Rangel-Buitrago, Nelson; Correa Arango, Ivan Dario; Universidad EAFIT. Departamento de Geología; Ciencias del Mar
    This work deals with the evolution of Bocas de Ceniza-Puerto Caiman, Galerazamba, Isla Cascajo and Punta Canoas coastal sectors, located along the 120 km-long coastline between the Magdalena River mouth and Cartagena de Indias, on the Caribbean coast of Colombia. Comparisons of coastline morphology from reliable ancient charts, modern bathymetric surveys and remote sensing data, show major changes (in some cases at kilometre-scale) related to the rapid erosion and formation of offshore sandy shoals, spits and beaches. These sediment bodies are linked to sediment supply from the Magdalena River. In 1935, after the emplacement of two jetties at the river mouth, sediment was channelled offshore and erosion ensued on the western part of the Magdalena delta. Spits and sandy shoals rapidly migrated down drift. As a result, a spit at Puerto Colombia - present on the 1935 and 1947 aerial photograms – progressively diminished and merged with the coastline between 1953 and 1959. South of this location, a new spit formed before 2000 and it presently shelters a marina at Puerto Velero. At Galerazamba, a 5 km-long spit at a high angle to the coastline, was present until 1864. It was replaced by a new spit, broadly parallel to shoreline, at some point before 1947. This feature was much smaller than the one previously observed and it has migrated down drift until the present. High rates of accretion were also observed around Isla Cascajo, a rocky island that caused the development of a rapidly growing tombolo. At Punta Canoas, a spit formed between 1947 and 1961 and, then migrated southwards.