Publications by authors named "N Johannesen"

This paper presents quasiexperimental evidence of Covid-19 transmission through casual contact between customers in retail stores. For a large sample of individuals in Denmark, we match card payment data, indicating exactly where and when each individual made purchases, with Covid-19 test data, indicating when each individual was tested and whether the test was positive. The resulting dataset identifies more than 100,000 instances where an infected individual made a purchase in a store and, in each instance, allows us to track the infection dynamics of other individuals who made purchases in the same store around the same time.

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This paper uses transaction-level bank account data from Denmark to study the dynamics of consumer spending during the Covid-19 pandemic. We document that aggregate spending initially dropped by almost 30% but recovered almost fully after the first wave. While spending plummeted in categories severely affected by supply restrictions, it increased in unaffected categories.

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This paper uses real-time transaction data from a large bank in Scandinavia to estimate the effect of social distancing laws on consumer spending in the coronavirus 2019 (COVID-19) pandemic. The analysis exploits a natural experiment to disentangle the effects of the virus and the laws aiming to contain it: Denmark and Sweden were similarly exposed to the pandemic but only Denmark imposed significant restrictions on social and economic activities. We estimate that aggregate spending dropped by around 25% (95% CI: 24 to 26%) in Sweden and, as a result of the shutdown, by 4 additional percentage points (95% CI: 3 to 5 percentage points [p.

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Aspirin and clopidogrel are important drugs in the secondary prevention of ischemic events. A considerable individual variation in platelet response to these drugs has, however, been reported, and high residual platelet reactivity despite treatment may be an independent risk factor for ischemic events. Most studies have been undertaken in patients with coronary heart disease, but patients with peripheral artery disease (PAD) may exhibit greater residual platelet reactivity, possibly because of platelet activation by a larger area of diseased endothelium.

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Objective: To compare 1-year potencies' of heparin-bonded PTFE [(Hb-PTFE) (Propaten(®))] grafts with those of ordinary polytetraflouroethylene (PTFE) grafts in a blinded, randomised, clinically controlled, multi-centre study.

Materials And Methods: Eleven Scandinavian centres enrolled 569 patients with chronic functional or critical lower limb ischaemia who were scheduled to undergo femoro-femoral bypass or femoro-poplitaeal bypass. The patients were randomised 1:1 stratified by centre.

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