61 research outputs found

    Tailoring transport properties of phase-separated manganite films with ordered magnetic nanostructures

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    International audienceThe magnetotransport properties of thin manganite films (La 0.7 Ca 0.3 MnO 3) coupled with arrays of permalloy (Py) nanodots deposited on the surface of the film is studied as a function of temperature , magnetic field and size of the dots. In the presence of the magnetic dots, a reduction of the electrical resistivity is observed, especially at the insulator-to-metal transition, as well as a shift of the transition peak towards higher temperature. This indicates that, due to the local interface exchange coupling, highly conductive ferromagnetic domains are nucleated in the manganite film underneath the Py nanodots. The use of a simplified resistor network model allows us to estimate the size of the metallic regions induced by the exchange coupling. At low temperatures, these regions extend ∼ 70 nm beyond the edge of the nanodots, a lengthscale comparable to the correlation length of the ferromagnetic clusters in the phase-separated state of La 0.7 Ca 0.3 MnO 3

    Modern pollen-vegetation relationships along a steep temperature gradient in the Tropical Andes of Ecuador

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    This is the author accepted manuscript. The final version is available from Cambridge University Press via the DOI in this record.The characterization of modern pollen rain assemblages along environmental gradients is an essential prerequisite for reliable interpretations of fossil pollen records. In this study, we identify pollen-vegetation relationships using modern pollen rain assemblages in moss polsters (n = 13) and lake sediment surface samples (n = 11) along a steep temperature gradient of 7°C (3100–4200 m above sea level) on the western Andean Cordillera, Ecuador. The pollen rain is correlated to vascular plant abundance data recorded in vegetation relevées (n = 13). Results show that pollen spectra from both moss polsters and sediment surface samples reflect changes in species composition along the temperature gradient, despite overrepresentation of upper montane forest taxa in the latter. Estimated pollen transport distance for a lake (Laguna Llaviucu) situated in a steep upper montane forest valley is 1–2 km, while a lake (Laguna Pallcacocha) in the páramo captures pollen input from a distance of up to 10–40 km. Weinmannia spp., Podocarpus spp., and Hedyosmum sp. are indicators of local upper montane forest vegetation, while Phlegmariurus spp. and Plantago spp. are indicators for local páramo vegetation.Earth and Life Science council (ALW) of the Netherlands Organisation of Scientific Researc

    Endemism in the genus Pertusaria (Pertusariales, lichenized Ascomycota) from the Galapagos Islands

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    This revision of Pertusaria in the Galapagos Islands documents twenty-four species, twenty-two being new to the archipelago. Secondary chemistry correlates well with morphology and anatomy and is particularly useful in distinguishing these taxa. Eight species are described as new to science, and seven are known only from the Galapagos: Pertusaria albineoides, P. cerroazulensis, P. darwiniana, P. medullamarilla, P. stictica, P. thioisidiata and P. xanthoisidiata. Pertusaria lueckingii is new, but it also occurs in Central America (El Salvador). Three new endemic varieties are described based on their chemistry: Pertusaria thioisidiata var. isidiogyrophorica, P. tejocotensis var. stictica and P. xantholeucoides var. thamnolica. In contrast with previous studies on other genera where rates of endemism of 8–10% were observed, in Pertusaria 30–37% of all species and 41–46% of all taxa are considered endemic

    Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

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    Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk

    Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

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    This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

    Implementación de un sistema para la generación automática de llamadas salientes en un call center

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    El proyecto que se implementó consiste en un sistema telefónico basado en Asterisk, para lo cual se desarrolló una aplicación PHP que hace uso de la Interfaz de Administración de Asterisk (AMI), capaz de generar automáticamente llamadas salientes programadas en base al monto adeudado por el cliente. Para esto se estableció como escenario de prueba una empresa de gestión de cobranzas, que mantiene una base de datos de los clientes que poseen una tarjeta de crédito, dicha base es actualizada periódicamente por el administrador del sistema. Al momento de ejecución de las llamadas se valida que la grabación es escuchada, si no es así se programa la realización de una segunda llamada. Adicionalmente, periódicamente se genera un reporte de las llamadas realizadas a los clientes, el cual es entregado a la empresa
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