Background. Understanding COVID-19 dynamics in Colombia during the first pandemic year (2020) gives important insights surrounding population’s exposure risk and specific susceptibilities. Seroprevalence studies can aid in having a broader understanding of the disease, offering a more inclusive view of the pandemic’s impact across the population. Methods. A population-based cross-sectional study to assess antibodies against SARS-CoV-2 in 10 Colombian cities was developed between September and December 2020. Cities were grouped according development typology (Robust (RD), Intermediate (ID) and Incipient (InD)). Detection of total antibodies (IgM + IgG) against SARS-CoV-2 was employed. Univariate Odds Ratios (OR) were estimated for antibody results and selected variables. Results. About 3124 children aged between 5 and 17 years were included. Factors related to lower seropositive results were affiliation to the employer-based health insurance in RD and ID cities (OR: 0.579, 95% CI 0.477-0.703, OR: 0.648, 95%CI 0.480-0.874 respectively) and living in a household with adequate access to public services only for ID cities (OR: 0.679. 95% CI 0.491-0.939). Higher seropositivity rates in RD and ID cities were seen in children belonging to the low socioeconomic stratum (RD: OR: 1.758, 95% CI 1.427-2.165; ID: OR: 2.288, 95% CI 1.599-3.275) and living in an overcrowded household (RD: OR: 1.846, 95% CI 1.467-2.323; ID: OR: 2.379, 95% CI 1.769-3.199). Conclusions. Children and adolescents showed substantial impact from the COVID-19 pandemic. Disadvantageous living conditions were found to be significantly related to having a positive SARS-CoV-2 antibody test. These results highlight the need to prioritize vulnerable populations in the context of health emergencies.

La “Merluza peruana” Merluccius gayi peruanus (Ginsburg, 1954), es la especie más abundante y económicamente importante en la pesquería de arrastre de fondo en el Perú. El objetivo del presente trabajo fue evaluar los índices parasitológicos de la merluza peruana M. gayi peruanus procedentes del Terminal Pesquero de Ventanilla durante los meses de enero a febrero del 2014. Se recogieron los parásitos, se fijaron, preservaron y se cuantificaron mediante procedimientos estandarizados. Se colectó un total de quince especies parásitas, con una abundancia media total y de riqueza de especies de 1,55 y 0,90. Los ectoparásitos estuvieron representados por el monogeneo Anthocotyle americana y los copépodos Caligus debueni, y Neobrachiella insidiosa pacifica. Los endoparásitos por los digeneos Aporocotyle wilhelmi, Derogenes varicus y Lecithochirium genypteri. Los cestodos fueron Diphyllobothrium pacificum, Diphyllobothrium arctocephalinum, Callitetrarhynchus gracilis, Grillotia dollfusi y Clestobothrium crassiceps. Los nematodos se identificaron como Anisakis simplex y Contracaecum sp. Los acantocefalos corresponden a Corynosoma obtuscens y Bolbosoma sp. Clestobothrium crassiceps, A. wilhelmi, A. americana y A. simplex presentaron la mayor frecuencia de dominancia. La prevalencia y abundancia media de C. crassiceps estuvo asociada con la longitud total del hospedero. Solo A. wilhelmi, presentó valores de factor de condición de la merluza peruana más altos en los peces no parasitados. Los índices de interactividad (CC ) de ectoparásitos y endoparásitos mostraron que 50 las comunidades parasitarias fueron mayormente no interactivas o aisladas. Los cuatro estimadores no paramétricos Chao-2, Jacknife-1, Jacknife-2 y Bootstrap para determinar la riqueza de especies parasitas indicaron que se requiere aumentar el esfuerzo de muestreo en la merluza peruana.

In vitro embryo production is a cutting-edge technology in constant evolution and has been used routinely. With the objective of improving genetic value, recent studies have been focused on the production of high-performance descendants from early prepubertal animals. The aim of this study was to compare hormonal protocols of ovarian stimulation for laparoscopic ovum pick-up in prepubertal sheep, to determine ovarian response and number of oocytes. For this study, 36 Santa Ines sheep, aged between 4 and 8 weeks, were submitted to a progestogen-based, short-term ovulation induction protocol (without use of prostaglandin F2α), and following 36 h, ovarian stimulation (300 IU of eCG) associated with different regimens of administration of FSH, according to experimental group. The ewes were divided into 1 of 6 groups: 2 groups received 80 mg of FSH by either single administration in the first group (G80U) or multiple constant administrations at 12-h intervals in the second group (G80M); animals belonging to 2 other groups received 160 mg in the same fashion, in a single-dose regimen (group G160U) or in multiple administrations (group G160M). The other 2 groups constituted the control groups: one received no hormonal treatment for ovulation induction and ovarian stimulation (GCN); the other received the ovulation induction protocol, but no ovulation stimulation was carried out (GCI). The animals were submitted to laparoscopic ovum pick-up 48 h following the beginning of the ovarian stimulation. The number of follicles viewed (FV), aspirated (FA), and recovered (OR) laparoscopically was recorded. Data were assessed using the one-way ANOVA test, and the comparison among groups was carried out using the Tukey test. The mean of follicles visualised, aspirated, and oocytes recovered are shown in Table 1. Group G160U had a better result regarding OR compared with the other groups. Moreover, the current study highlights that laparoscopic ovum pick-up for in vitro maturation using prepubertal ewes is viable for commercial purposes. More studies are required in order to improve the quality of oocytes and successful in vitro maturation rates. Table 1.Results of visualised follicles (VF), aspirated follicles (AF), and oocytes retrieved (OR)

El presente trabajo es un estudio cualitativo con enfoque interpretativo, que tiene como objeto indagar en los procesos de construcción subjetiva de la ciudadanía y la participación de las juventudes chilenas, con el propósito de comprender algunas de las prácticas juveniles que dan cuenta de su imaginario sobre la política, en el marco del primer proceso Constituyente, que incorpora de manera masiva a la ciudadanía en Chile. La técnica utilizada para este estudio fue la entrevista en profundidad a jóvenes entre 15 y 18 años del gran Valparaíso. Los resultados preliminares indican que existe una transformación en el imaginario de las juventudes, respecto a los conceptos de Estado y de nación, que estarían incidiendo en la forma como aquellas se implican en los procesos políticos, identificándose con prácticas vinculadas a organizaciones autoconvocadas, con una relación diferente frente al poder y orientada a soluciones concretas.