Browsing by Author "Contreras, Patricio"

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    Free-roaming domestic cats near conservation areas in Chile: Spatial movements, human care and risks for wildlife
    (2021) Jose Lopez-Jara, Maria; Sacristan, Irene; Farias, Ariel A.; Maron-Perez, Francisca; Acuna, Francisca; Aguilar, Emilio; Garcia, Sebastian; Contreras, Patricio; Silva-Rodriguez, Eduardo A.; Napolitano, Constanza
    Free-roaming domestic cats can negatively affect wildlife, and understanding how they use space is fundamental to predict their potential impacts. In this study we describe the use of space of 48 owned free-roaming cats and assess the level of care provided by owners in rural areas near priority conservation areas in southern Chile. Additionally, we use camera trap data from two protected areas to assess spatial overlap with wild vertebrates, particularly the guigna (Leopardus guigna), a vulnerable forest-dwelling felid. Cat home ranges were variable (1-47.2 hectares) and their activity was mostly concentrated within 100 meters of the household, with maximum foray distances up to 2.5 km. Cats used wooded areas (12% of fixes on average), mostly native forest, where spatial overlap with endemic and/or threatened species was documented. Nonetheless cats were infrequently detected in nearby protected areas (1.7% of GPS locations and 1% of the cameras). The use of wooded areas was strongly associated with the distance from the household to the forest edge and home range areas were negatively associated with house density. Our findings suggest that in areas isolated from households (>200 m), the problem of cats is marginal and restricted to the edges. Management was in general deficient, observing birth control in only 13% of cats and lack of preventive health care in 86% of cats. Cat impacts could be exacerbated under increasing land subdivision in southern Chile where, without population control strategies, cats may become an emergent threat for native wildlife.
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    Insulin sensitivity and testicular function in a cohort of adult males suspected of being insulin-resistant
    (2018) Contreras, Patricio; Serrano, Felipe; Salgado, Ana; Vigil Portales, María del Pilar
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    Large-scale assessment of the presence of Darwin's fox across its newly discovered range
    (2018) Silva-Rodríguez, Eduardo A.; Ovando, Erwin; González, Danilo; Zambrano, Brayan; Sepúlveda, Maximiliano A.; Svensson, Gabriella L.; Cárdenas, René; Contreras, Patricio; Farías Piccolini Ariel Alejandro
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    Nickel Nanopillar Arrays Electrodeposited on Silicon Substrates Using Porous Alumina Templates
    (2020) Bejide, Matias; Contreras, Patricio; Homm, Pia; Duran, Boris; Garcia-Merino, Jose Antonio; Rosenkranz, Andreas; Denardin, Juliano C.; del Rio, Rodrigo; Hevia, Samuel A.
    Nickel nanopillar arrays were electrodeposited onto silicon substrates using porous alumina membranes as a template. The characterization of the samples was done by scanning electron microscopy, X-ray diffraction, and alternating force gradient magnetometry. Ni nanostructures were directly grown on Si by galvanostatic and potentiostatic electrodeposition techniques in three remarkable charge transfer configurations. Differences in the growth mechanisms of the nanopillars were observed, depending on the deposition method. A high correlation between the height of the nanopillars and the charge synthesis was observed irrespective of the electrochemical technique. The magnetization measurements demonstrated a main dependence with the height of the nanopillars. The synthesis of Ni nanosystems with a controllable aspect ratio provides an effective way to produce well-ordered networks for wide scientific applications.