Space charge in drift chambers operated with the Xe,CO2(15%) mixture

Using prototype modules of the ALICE Transition Radiation Detector we investigate space charge effects and the dependence of the pion rejection performance on the incident angle of the ionizing particle. The average pulse height distributions in the drift chambers operated with the Xe,CO2(15%) mixture provide quantitative information on the gas gain reduction due to space charge accumulating during the drift of the primary ionization. Our results demonstrate that the pion rejection performance of a TRD is better for tracks which are not at normal incidence to the anode wires. We present detailed simulations of detector signals, which reproduce the measurements and lend strong support to our interpretation of the measurements in terms of space charge effects.Comment: 18 pages, 10 figures, accepted for publication in Nucl.Instrum.Meth. A. Data files available at http://www-alice.gsi.de/tr

Changes in wild meat hunting and use by rural communities during the COVID-19 socio-economic shock

There has been limited quantitative research into the effects of socio-economic shocks on biological resource use. Focusing on wild meat hunting, a substantial livelihood and food source in tropical regions, we evaluated the impacts of the shock from Nigeria’s COVID-19 lockdown on species exploitation around a global biodiversity hotspot. Using a three-year quantitative dataset collected during and after the lockdown (covering 1,008 hunter-months) and matching by time of year, we found that successful hunting trip rates were more frequent during lockdown, with a corresponding increase in the monthly number, mass, and value of animals caught. Moreover, hunters consumed a larger proportion of wild meat and sold less during lockdown compared to non-lockdown periods. These results suggest that local communities relied on wild meat to supplement reduced food and income during lockdown, buffering COVID-19’s socio-economic shock. Our findings also indicate that wild species may be especially vulnerable to increased hunting pressure during such shocks