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Rise in Teen Marijuana Use Stalls, Use of Synthetic Marijuana and ‘Bath Salts’ is Very Low

ANN ARBOR — National samples of 45,000 to 50,000 students in three grades (8, 10, and 12) have been surveyed every year since 1991 as part of the nationwide Monitoring the Future study. Among the most important findings from this year’s survey of U.S. secondary school students are the following:

Marijuana. After four straight years of increasing use among teens, annual marijuana use showed no further increase in any of the three grades surveyed in 2012. The 2012 annual prevalence rates (i.e., percent using in the prior 12 months) were 11%, 28%, and 36% for 8th, 10th, and 12th graders, respectively. (Among the 8th graders there was a modest decline across the past two years—from 13.7% in 2010 to 11.4% in 2012—that reached statistical significance.) (more…)

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State-Mandated Planning, Higher Resident Wealth Linked to More Sustainable City Transportation

COLUMBUS, Ohio – Transportation practices tend to be more environmentally friendly in wealthier metropolitan areas located within states that mandate comprehensive planning, new research suggests.

The study involved an examination of 225 U.S. metropolitan areas between 1980 and 2008 to gauge how sustainable their transportation practices were and determine what kinds of socioeconomic factors appeared to influence those practices. (more…)

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Droughts are Pushing Trees to the Limit

Droughts in the Southwest made more severe by warming temperatures are putting plants in stressful growing conditions, a new study has found, identifying an increasingly water-thirsty atmosphere as a key force that sucks moisture from plants, leading to potentially higher stress – especially in mid and low elevations.

As temperatures rise and droughts become more severe in the Southwest, trees are increasingly up against extremely stressful growing conditions, especially in low to middle elevations, University of Arizona researchers report in a study soon to be published in the Journal of Geophysical Research Biogeosciences.

Lead author Jeremy Weiss, a senior research specialist in the UA department of geosciences, said: “We know the climate in the Southwest is getting warmer, but we wanted to investigate how the higher temperatures might interact with the highly variable precipitation typical of the region.” (more…)

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