Room-temperature ionic liquids (ILs) are being promoted as environmentally friendly alternatives to volatile organic solvents currently used by industry. Because ILs are novel and not yet in widespread use, their potential impact on aquatic organisms is unclear. We studied the effects of several ILs on the survivorship and behavior (movement and feeding rates) of the freshwater pulmonate snail, Physa acuta. Median lethal concentrations (LC50s) of ILs with imidazolium- and pyridinium-based cations and Br- and PF6- as anions ranged from 1 to 325 mg/L. Toxicity was greatest for ILs with eight-carbon alkyl chains attached to both imidazolium and pyridinium rings and declined with shorter alkyl chains, indicating a positive relationship between alkyl chain length and toxicity. Compared to controls, snails moved more slowly when exposed to butyl- and hexyl-cation ILs at 1 to 3% of LC50 concentrations but were not affected at higher IL concentrations (4-10% of LC50), which is characteristic of U-shaped dose-response curves. Snail movement was not affected by ILs with octyl alkyl groups. Grazing patterns, however, indicated that snails grazed less at higher IL concentrations. Physa acuta egestion rates were reduced in the presence of ILs at 3 to 10% of LC50 concentrations. Thus, nonlethal IL concentrations affected P. acuta behaviors, potentially impacting individual fitness and food web interactions. These results provide initial information needed to assess the potential hazards of ILs should they reach freshwater ecosystems.

The transmission of SARS in Toronto was limited primarily to hospitals and to households that had had contact with patients. For every case of SARS, health authorities should expect to quarantine up to 100 contacts of the patients and to investigate 8 possible cases. During an outbreak, active in-hospital surveillance for SARS-like illnesses and heightened infection-control measures are essential.

Information does not yet exist on the characteristics and outcomes of patients hospitalized with coronavirus disease 2019 (COVID-19) who are discharged to the home setting. Using rich data from home health care (HHC), the authors describe characteristics of COVID-19 survivors upon admission to HHC, the home visits they received, and the extent of recovery among those discharged from HHC. They also profile the risk factors associated with rehospitalization and death.

Overall, the risks of adverse outcomes of elective daytime procedures were similar whether or not the physician had provided medical services the previous night. (Funded by the University of Toronto Dean's Fund and others.).

Nine experiments examined the formation of an abstract category representation for the spatial relation between by 6- to 10-month-old infants. The experiments determined that 9- to 10-month-olds, but not 6- to 7-month-olds, could form an abstract category representation for between when performing in an object-variation version of the between categorization task. The results also demonstrated that 6- to 7-month-olds could form category representations for between in the object-variation version of the between categorization task but that such representations were specific to the particular objects presented. The evidence confirms that representations for different spatial relations emerge at different points during development, and suggests that each representation undergoes its own period of development from concrete to abstract.

PAs reduce resident workload and improve care on surgical teams in a tertiary hospital.

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