SummaryAn epidemiologic survey (n=466) was conducted in an area of subtropical rainforest in north-west Ecuador with the following objectives: (1) to determine the prevalence of cutaneous leishmaniasis (CL), (2) to identify the Leishmania species causing human disease, (3) to investigate the major clinical manifestations of leishmaniasis, (4) to study cellular and humoral immune response indicators associated with disease status and (5) to identify risk factors for CL. Fourteen per cent of subjects had parasitologically confirmed CL; 33% had evidence of prior disease. However, 17.2% of subjects with a negative CL clinical history presented with a positive Montenegro skin test (MST), indicating the possibility of subclinical infection. The species isolated from subject lesions were L. guyanensis (63%), L. panamensis (33%), and L. brazilensis (4%). Mean specific anti-Leishmania IgG and IgM OD serum levels were highest in subjects diagnosed with current CL, followed by those with prior CL, and were lowest in healthy subjects, respectively (0.56 0.27 vs 0.33 0.2 vs 0.22 0.14; F-ratio=74; P<0.00001) and (665 270 vs 481 220 vs 301 128.5; F-ratio=37; P<0.00001). Likewise, subjects with present CL had measurably higher MST reactions (13 6.7 mm) than those with prior CL (10.9 7.8 mm) or healthy individuals (2.4 2.5 mm; F-ratio=106; P<0.00001). Serum concentrations of IgG were predicted by lesion number (t=2.5; P=0.018), size (t=3.7; P=0.0006), and duration (t=3.5; P=0.0013). Furthermore, the MST induration size increased as a function of lesion number (t=3.0; P=0.005) and size (t=3.4; P=0.022). Subject age and sex did not predict serum IgG or IgM concentrations or MST reactions in the 3 disease groups. Although no sex differences were found with respect to clinical characteristics, children^12 years of age were almost 3 times more likely to have CL lesions or scars located on the face and head area compared to adults (OR=2.75; 95% CI=1. 4-5.6, P=0.004). The risk factors associated with disease included age under 5 years (AOR=1.5; 95% CI=0.48-2.35), male gender in adults (AOR=2.8; 95% CI=1.1-7.8), and wood and/or cane exterior house walls (AOR=1.8; 95% CI=1.4-2.5). In contrast, electric home lighting was associated with decreased risk (AOR=0.7; 95% CI=0.4-2.3). The results suggest that it may be possible to modify a portion of the risk of CL by making changes in the housing environment which may help to reduce the amount of human-vector contact.

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En el presente trabajo de investigación se evaluó agronómicamente el cultivo de rábano (raphanus sativus) bajo el sistema de producción hidropónica tipo raíz flotante y se utilizó el diseño completamente con repeticiones de 56 contenedores por tratamiento. El cultivo en hidroponía, es una modalidad en el manejo de plantas, que permite su cultivo sin suelo. Mediante esta técnica se producen plantas principalmente de tipo herbáceo, aprovechando sitios o áreas no convencionales, sin perder de vistas las necesidades de las plantas, como luz, temperatura, agua y nutrientes. En el sistema hidropónico los elementos minerales esenciales son aportados por la solución nutritiva. El rendimiento de los cultivos hidropónicos puede duplicar o más los de los cultivos en suelo. La disponibilidad de agua y nutrientes, los niveles de radiación y temperatura del ambiente, la densidad de siembra o disposición de las plantas en el sistema hidropónico, la acción de patógenos o plagas, entre otros factores incidirán fuertemente en el rendimiento del cultivo. El modernismo permitió la introducción de los avances de la informática para el control y ejecución de actividades, que han hecho de la automatización del cultivo hidropónico una realidad. El ritmo de vida que llevamos hoy en día, ha impulsado al ser humano a la necesidad de obtener todo más rápidamente, Se concluyó que de los dos tratamientos que se evaluaron el mejor sistema fue el de soluciones concentradas de Nitrato de Potasio, amonio y Calcio denominada concentración de solución (a) bajo sistema de raíz flotante.

This paper presents a first estimation of the tourist test threshold for interchange fees that makes Peruvian small merchants indifferent between accepting cash and debit cards at the point of sale. We use the tourist test model (initially proposed by Rochet and Tirole), including tax evasion (Aurazo and Vasquez’s model) as an extra factor in the merchants’ decision between cash and card payments. Also, we revisit the existing empirical approaches and propose a new empirical approach, coined as the cash-flow approach, which assumes that small merchants estimate the overall cost in terms of the average ticket related to cash and card payments. Using a Survey on private costs of payment instruments conducted by the Central Reserve Bank of Peru in 2019, our estimates suggest that the tourist test threshold for debit cards is lower than the current interchange fee until 2019, even if tax evasion is not considered. Also, this study helps policymakers to better understand the factors around the merchants’ decision that may be considered to foster digital payments.