International travel in times of the COVID-19 pandemic: Evidence from German school breaks

The COVID-19 pandemic has triggered severe global restrictions on international travel with the intention of limiting the spread of SARS-CoV-2 across countries. This paper studies the effects of the partial relaxation of these travel restrictions in Europe during the summer months of 2020. It exploits the staggered start of the summer school breaks across German states as an exogenous shock to the travel opportunities of the population. While the school breaks also increased mobility within Germany, the event study regressions include disaggregated and time-varying controls for domestic mobility and local COVID-19-related restrictions. The resulting intention-to-treat effects of the relaxed travel restrictions show a significant and sizable increase of the COVID-19 incidence in German counties during the later weeks of the school breaks.

Oral Intake of EPA:DHA 6:1 by Middle-Aged Rats for One Week Improves Age-Related Endothelial Dysfunction in Both the Femoral Artery and Vein: Role of Cyclooxygenases

In humans, aging is associated with endothelial dysfunction and an increased risk of venous thromboembolism. Although intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) at a ratio of 6:1 by old rats improved the endothelial dysfunction in arteries, the impact on veins remains unclear. Eight-month-old male Wistar rats were either untreated or orally administered corn oil, EPA:DHA 1:1, or EPA:DHA 6:1 (500 mg/kg/d) for seven days. Vascular reactivity was studied by myography. In middle-aged femoral artery rings, acetylcholine caused a partial relaxation at low concentrations and a contractile response at high concentrations, whereas in the old femoral vein only a partial relaxation was observed. The EPA:DHA 6:1 treatment blunted the contractile response to acetylcholine in the middle-aged femoral artery and both EPA:DHA 6:1 and 1:1 increased the relaxation to acetylcholine in the old femoral vein. No such effects were observed with corn oil. Both the non-selective cyclooxygenase inhibitor indomethacin and the COX-1 inhibitor SC-560 increased the relaxation to acetylcholine in the middle-aged femoral artery whereas the COX-2 inhibitor NS-398 increased that in the middle-aged femoral vein. In conclusion, our results indicate that aging is associated with an endothelial dysfunction in the femoral artery and vein, which can be improved by EPA:DHA 6:1 treatment—most likely via a cyclooxygenase-dependent mechanism.

Survey of animal by-products in feedingstuffs before the reintroduction of processed animal proteins in aquafeed

Description. Since 2001, the number of bovine spongiform encephalopathy cases has drastically declined. A gradual lifting of the feed ban for aquaculture was possible in 2013 but this partial relaxation makes its control much more complex. Objectives. The objective was to have a practical overview of the current analytical situation and to highlight current and foreseen analytical gaps in the context of a progressive lifting of the ban. Method. Feed samples, collected before the partial lifting as regards aquafeed in 2013, were firstly analyzed by light microscopy. All samples were additionally analyzed by PCR in order to study the difficulties which would be faced with feeds produced after the relaxation. ELISA for the detection of milk proteins was also performed on samples in which ruminant DNA was detected. Results. When keeping the interpretation to the sole light microscopy results, all samples were in accordance to the legal requirements. Adding the PCR results made the interpretation more difficult. DNA of terrestrial animals was detected in nearly 65% of the samples. Apart from aquafeeds, the presence of ruminant DNA could be explained by the use of dairy products confirmed in most cases by ELISA. In aquafeeds, 23% (13/57) of the samples tested positive for ruminant DNA but only three of them also tested positive for milk proteins. Conclusions. The study underlined the crucial need for complementary analytical solutions in order to identify the source of the detected DNA.