Mars Extant Life: What's Next? Conference Report.

On November 5-8, 2019, the "Mars Extant Life: What's Next?" conference was convened in Carlsbad, New Mexico. The conference gathered a community of actively publishing experts in disciplines related to habitability and astrobiology. Primary conclusions are as follows: A significant subset of conference attendees concluded that there is a realistic possibility that Mars hosts indigenous microbial life. A powerful theme that permeated the conference is that the key to the search for martian extant life lies in identifying and exploring refugia ("oases"), where conditions are either permanently or episodically significantly more hospitable than average. Based on our existing knowledge of Mars, conference participants highlighted four potential martian refugium (not listed in priority order): Caves, Deep Subsurface, Ices, and Salts. The conference group did not attempt to reach a consensus prioritization of these candidate environments, but instead felt that a defensible prioritization would require a future competitive process. Within the context of these candidate environments, we identified a variety of geological search strategies that could narrow the search space. Additionally, we summarized a number of measurement techniques that could be used to detect evidence of extant life (if present). Again, it was not within the scope of the conference to prioritize these measurement techniques-that is best left for the competitive process. We specifically note that the number and sensitivity of detection methods that could be implemented if samples were returned to Earth greatly exceed the methodologies that could be used at Mars. Finally, important lessons to guide extant life search processes can be derived both from experiments carried out in terrestrial laboratories and analog field sites and from theoretical modeling.

Case studies in dysphagia after pediatric brain injury.

The course of pediatric traumatic brain injury is not homogeneous because the underlying neuropathology can be so variable. Assessment, intervention, and recovery are examined among five individuals whose neuroradiologic imaging differed grossly on initial and early presentations after head trauma. Knowledge of the neuropathology in an overarching sense can be informative to a clinician's management of different swallowing problems after brain injury.

The effects of acute and repeated cocaine injections on protein kinase C activity and isoform levels in dopaminergic brain regions.

The present study was designed to assess the effects of acute and repeated cocaine exposure on protein kinase C (PKC) activity and the levels of calcium-dependent isoforms of PKC in mesocorticolimbic and nigrostriatal dopamine brain regions. Animals received repeated injections of saline or cocaine and were challenged with saline or cocaine 24 h or 7 days after the last of their daily injections. Animals were sacrificed 2, 6 or 24 h after the challenge injection and their brains were dissected and used in PKC studies. The data demonstrated that previously reported cocaine-induced increases in PKC activity in the ventral tegmental area are transient and not associated with changes in the levels of calcium-dependent isoforms of PKC. In addition, there was a decrease in membrane-associated PKC activity, with a concomitant increase in the levels of PKCbetaI in the medial prefrontal cortex 24 h after the last injection of cocaine. These data suggest that changes in PKC activity in the ventral tegmental area may be involved in the initiation of sensitization whereas changes in PKC activity in the medial prefrontal cortex may be related to the expression of the sensitized response to cocaine.