Trends in PM2.5 transition metals in urban areas across the United States

Using data from the Environmental Protection Agency’s Chemical Speciation Network, we have characterized trends in PM _2.5 transition metals in urban areas across the United States for the period 2001–2016. The metals included in this analysis—Cr, Cu, Fe, Mn, Ni, V, and Zn—were selected based upon their abundance in PM _2.5 , known sources, and links to toxicity. Ten cities were included to provide broad geographic coverage, diverse source influences, and climatology: Atlanta (ATL), Baltimore (BAL), Chicago (CHI), Dallas (DAL), Denver (DEN), Los Angeles (LA), New York City (NYC), Phoenix (PHX), Seattle (SEA), and St. Louis (STL). The concentrations of V and Zn decreased in all ten cities, though the V decreases were more substantial. Cr concentrations increased in cities in the East and Midwest, with a pronounced spike in concentrations in 2013. The National Emissions Inventory was used to link sources with the observed trends; however, the causes of the broad Cr concentration increases and 2013 spike are not clear. Analysis of PM _2.5 metal concentrations in port versus non-port cities showed different trends for Ni, suggesting an important but decreasing influence of marine emissions. The concentrations of most PM _2.5 metals decreased in LA, STL, BAL, and SEA while concentrations of four of the seven metals (Cr, Fe, Mn, Ni) increased in DAL over the same time. Comparisons of the individual metals to overall trends in PM _2.5 suggest decoupled sources and processes affecting each. These metals may have an enhanced toxicity compared to other chemical species present in PM, so the results have implications for strategies to measure exposures to PM and the resulting human health effects

Compassionate revanchism: The blurry geography of homelessness in the USA

In this article we move beyond the binary division between care and punishment in urban studies of homelessness to examine how caring institutions are themselves crucial to the punitive and exclusionary project of capitalist urbanisation. Based on ethnographic and archival analysis of homelessness management in Fresno, California, and Phoenix, Arizona, we show how punitive measures and institutions of care often emerge simultaneously and operate in tandem as part of a broader scheme for urban revitalisation. Further, we show how caring institutions themselves often perform the function of controlling homeless people’s movements in the city, while punitive institutions adopt more caring tactics. Thus, we argue for a focus on how compassion and criminalisation are regularly blurred

Dissociable Effects of Cocaine Dependence on Reward Processes: The Role of Acute Cocaine and Craving

The relative impact of chronic vs acute cocaine on dependence-related variability in reward processing in cocaine-dependent individuals (CD) is not well understood, despite the relevance of such effects to long-term outcomes. To dissociate these effects, CD (N=15) and healthy controls (HC; N=15) underwent MRI two times while performing a monetary incentive delay task. Both scans were identical across subjects/groups, except that, in a single-blind, counterbalanced design, CD received intravenous cocaine (30 mg/70 kg) before one session (CD+cocaine) and saline in another (CD+saline). Imaging analyses focused on activity related to anticipatory valence (gain/loss), anticipatory magnitude (small/medium/large), and reinforcing outcomes (successful/unsuccessful). Drug condition (cocaine vs saline) and group (HC vs CD+cocaine or CD+saline) did not influence valence-related activity. However, compared with HC, magnitude-related activity for gains was reduced in CD in the left cingulate gyrus post-cocaine and in the left putamen in the abstinence/saline condition. In contrast, magnitude-dependent activity for losses increased in CD vs HC in the right inferior parietal lobe post-cocaine and in the left superior frontal gyrus post-saline. Across outcomes (ie, successful and unsuccessful) activity in the right habenula decreased in CD in the abstinence/saline condition vs acute cocaine and HC. Cocaine-dependent variability in outcome- and loss-magnitude activity correlated negatively with ratings of cocaine craving and positively with how high subjects felt during the scanning session. Collectively, these data suggest dissociable effects of acute cocaine on non-drug reward processes, with cocaine consumption partially ameliorating dependence-related insensitivity to reinforcing outcomes/‘liking', but having no discernible effect on dependence-related alterations in incentive salience/‘wanting'. The relationship of drug-related affective sequelae to non-drug reward processing suggests that CD experience a general alteration of reward function and may be motivated to continue using cocaine for reasons beyond desired drug-related effects. This may have implications for individual differences in treatment efficacy for approaches that rely on reinforcement strategies (eg, contingency management) and for the long-term success of treatment