No evidence for population-level benefits of polyandry in sharks and rays.

Mating system variation refers to the spectrum between genetic monogamy and polyandry, and has important consequences for sexual conflict, sexual selection and individual fitness in animals. Theoretically this variation could also have substantial population-level effects, influencing population viability and extinction risk. Evidence for these effects is mixed, in part due to the fact that substantial environmental change is thought to be required for them to have visible demographic consequences.

Characteristics of COVID-19 and mortality-associated factors during the first year of the pandemic in southeast Mexico.

The present study was designed to evaluate the clinical characteristics of COVID-19 and mortality-associated factors during the first year of the pandemic in patients from southeastern Mexico. A total of 953 records from patients with COVID-19 were cross-sectionally studied in a primary care hospital in southeast Mexico between 2020 and 2021. The prevalent symptoms were fever (78.

Hypozincemia in Mexican patients with diabetic foot ulcer treated out of hospital.

Objective: To know the frequency of people with hypozincemia in a group of Mexican patients with Diabetic Foot Ulcers (DFU)m and its relationship with metabolic and clinical profile.

Material And Methods: Cross-sectional, analytical, and observational study in patients with and without DFU, treated in Family Medicine Units from Instituto Mexicano del Seguro Social (IMSS) in Mérida, Yucatán, México. Frequency of hypozincemia (Zn serum < 70 g/ml) and its relationship with the levels of Glycosylated Hemoglobin (HbA1c), cholesterol and triglycerides was analyzed.

Trapping and manipulation of microparticles using laser-induced convection currents and photophoresis.

In this work we demonstrate optical trapping and manipulation of microparticles suspended in water due to laser-induced convection currents. Convection currents are generated due to laser light absorption in an hydrogenated amorphous silicon (a:Si-H) thin film. The particles are dragged towards the beam's center by the convection currents (Stokes drag force) allowing trapping with powers as low as 0.