This paper examines the determinants of social distancing during the COVID-19 epidemic. We classify state and local government actions, and we study multiple proxies for social distancing based on data from smart devices. Mobility fell substantially in all states, even ones that have not adopted major distancing mandates. There is little evidence, for example, that stay-at-home mandates induced distancing. In contrast, early and information-focused actions have had bigger effects. Event studies show that first case announcements, emergency declarations, and school closures reduced mobility by 1-5% after 5 days and 7-45% after 20 days. Between March 1 and April 11, average time spent at home grew from 9.1 hours to 13.9 hours. We find, for example, that without state emergency declarations, event study estimates imply that hours at home would have been 11.3 hours in April, suggesting that 55% of the growth comes from emergency declarations and 45% comes from secular (non-policy) trends. State and local government actions induced changes in mobility on top of a large response across all states to the prevailing knowledge of public health risks. Early state policies conveyed information about the epidemic, suggesting that even the policy response mainly operates through a voluntary channel.
The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. At least one co-author has disclosed a financial relationship of potential relevance for this research. Further information is available online at http://www.nber.org/papers/w27280.ack NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.
Background: The treatment of keloids remains challenging. Cryosurgery and intralesional corticosteroids have been considered as the mainstream of therapy; however, the long-term use of corticosteroids has been found to be associated with serious side effects. Intralesional 5-fluorouracil (5-FU) has only been used in one study for the treatment of hypertrophic scars and keloids, mostly in combination with other treatments. The efficacy of 5-FU as an individual therapeutic agent is unknown. Objective: To evaluate the efficacy and safety of intralesional injections of 5-FU in the treatment of small keloid lesions. Methods: Twenty-four (12 male, 12 female) consecutive patients with keloids of 6 cm or less in their maximum dimension were treated with intralesional injections of 50–150 mg 5-FU per week for a maximum of 16 injections. Results: One third (8/24, 33.3%) of the patients showed more than 75% flattening of the keloid. Three out of 8 patients (with >75% flattening) required less than 16 (13, 13 and 15) injections for achieving the desired response. Overall, about half of the patients showed more than 50% flattening of the treated keloid. A correlation with the duration of keloid was found. Six (54.5%) out of 11 patients with keloids of ≤5 years duration, in contrast to only 2 (15.4%) out of 13 patients with keloids of >5 years duration showed more than 75% flattening (p < 0.05). Side effects included pain (all patients), hyperpigmentation (all patients) and ulceration (1 patient). No difference in peripheral blood count was noted before, during and after the therapy. Conclusion: Intralesional 5-FU can be safely used for the management of small keloids of shorter duration.
the categorization of certain passive activities as nonmeaningful and that activities were assessed by self-report. Nonetheless, we believe engagement in meaningful activities is central to one's identity and well-being.
Preeclampsia (PE) is a major cause of maternal and perinatal morbidity and mortality. The genesis of PE is related to deficient trophoblast invasion of maternal spiral arteries, which might result in a reduction of placental (PL) oxygen (O(2)). An absence of increased O(2) that normally occurs around the 10-12th wk of gestation results in aberrant expression of genes that might contribute to the pathophysiology of PE. We examined the expression and regulation of PL 11 beta-hydroxysteroid dehydrogenase 2 (11 beta-HSD) in normal pregnancies and in PE. Two types of 11 beta-HSD exist in the placenta, 11 beta-HSD1 and 11 beta-HSD2. 11 beta-HSD2 is thought to protect the fetus from cortisol excess. In PE, both the expression and activity of PL 11 beta-HSD2 were reduced significantly compared with those in age-matched controls. As PE is associated with a reduction of PL O(2), we next investigated whether in normal pregnancy 11 beta-HSD2 expression changes at the time of the increase in O(2). 11 beta-HSD2 was detected as early as 5 wk, with expression limited to the syncytiotrophoblast (ST). At 10-12 wk, this expression increased and was also found in the cytotrophoblast and extravillous trophoblast. These results were substantiated by Western blot. The ability of O(2) to regulate 11 beta-HSD2 was determined both in cultures of villous explant from early gestation and in term trophoblast cells after incubation under 3% or 20% O(2). Villous explants cultured under 20% O(2) showed higher enzyme activity and expression compared with 3% O(2). Term trophoblast cells also exhibited higher enzyme activity at 20% vs. 3% O(2). No change in 11 beta-HSD1 expression was observed in early pregnancy or in PE. This is the first report to suggest that 11 beta-HSD2 is O(2) dependent in first and third trimester placenta during human gestation.
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