Optical design of an off-axis four-mirror objective system (OFOS) for a thermal camera

The optical design of a reflective objective system of a thermal camera for a syndromic surveillance system that captures bio-clinical signals, like temperature, directly related to the physical symptoms of the COVID-19 disease through thermal images is presented. The design is based on an off-axis four mirror system that allows for correcting spherical, coma, astigmatism, and field curvature aberrations. The OFOS design works on wavelengths of 7.5 µm - 14 µm, with an f-number less than 5, and a field of view (FOV) greater than 10 degrees. © COPYRIGHT SPIE. Downloading of the is permitted for personal use only.

Subsistence Hunting During the COVID-19 Pandemic: The Case of the White-Tailed Deer (Odocoileus virginianus) in Rural Communities of Calakmul, Campeche, Mexico

Subsistence hunting for obtaining wild meat is a common practice in rural neotropical communities. Like other peasant practices disrupted by the COVID-19 pandemic, subsistence hunting could exacerbate pressure on wild mammals whose greater size contributes to feeding the hunter and his family. Thus, in the context of the pandemic, we assessed the subsistence hunting of the white-tailed deer (Odocoileus virginianus), one of the main traditional game species in the Calakmul region, Campeche, Mexico, and compared this activity with its pre-pandemic levels of such vertebrate species. Based on ethnographic information and hunting records from three rural communities, we found that in one trimester (July-September 2020) of the rainy season, a total of 26 white-tailed deer (923 kg of game biomass) were obtained by local peasant-hunters carrying out hunting mostly alone. Most peasant-hunters interviewed (36 of 51) stated that they hunted daily, and only a few hunted once a week or once a month (8 and 3%, respectively). This hunting activity and modalities were carried out at night (68%) versus day, stalking (21%) and opportunist (11%) near their community. The game biomass and hunting frequency in the studied communities were twice as high during the pandemic, compared to similar pre-pandemic periods in the region. Our survey highlights the need to expand monitoring and evaluation (during and after the pandemic) of subsistence hunting on key species, such as white-tailed deer, in order to ensure conservation and sustainable use of wildlife in this important Mesoamerican region.

Design of a compact off-axis four-mirror objective system for a thermal camera.

The optical design of a compact off-axis four-mirror objective system (OFOS) of a thermal camera for a syndromic surveillance system that captures bioclinical signals, like temperature, directly related to the physical symptoms of the COVID-19 disease through thermal images is presented. The OFOS design works on wavelengths of 7.5-14 µm, with an f-number of 4, and a field of view (FOV) of 24×4 deg.