Droplets Sliding down a Vertical Surface under Increasing Horizontal Forces.

We have investigated the retention forces of liquid drops on rotating, vertical surfaces. We considered two scenarios: in one, a horizontal, centrifugal force pushes the drop toward the surface (?pushed drop? case), and in the other, a horizontal, centrifugal force pulls the drop away from the surface (?pulled drop? case). Both drops slide down as the centrifugal force increases, although one expects that the pushed drop should remain stuck to the surface. Even more surprising, when the centrifugal force is low, the pushed drop moves faster than the pulled drop, but when the centrifugal force is high, the pushed drop moves much slower than the pulled drop. We explain these results in terms of interfacial modulus between the drop and the surface.

Trends in underage tobacco sales: an update on the past decade of compliance checks in Hawai'i.

Tobacco use remains the leading cause of preventable death in the United States and is a major concern in the adolescent population. Preventing youth from starting to smoke is a key public health priority, as a majority of adult smokers started smoking by age 18. Controlling access to tobacco in retail outlets has been shown to be an effective measure for reducing the use of tobacco among minors. In order to control the sales of tobacco to minors in the retail environment, the Synar Amendment requires states to conduct annual, random, and unannounced tobacco sales compliance inspections. Synar compliance inspections started in Hawai'i in 1996, reducing the sales of tobacco to minors almost 40.0% by 2003. The current paper aims to expand on past surveillance findings to examine the Synar compliance inspection results in Hawai'i from 2004 to 2013 and to identify factors associated with minors' successfully purchasing tobacco. Surveillance of the past ten years showed that noncompliance rates remained low, ranging from a high of 11.2% in 2008 to a low of 4.3% in 2012; this number was 7.5% in 2013. Three factors were significantly associated with successful tobacco purchases by a minor in 2013: whether a clerk requested a minor's identification, the gender of the minor, and whether self-service of tobacco products was available. Other significant factors varied by year. Findings from this study are needed for continued surveillance, to implement effective anti-tobacco policies, and to develop policies aimed at emerging tobacco products, such as electronic cigarettes.