Matthew A. Johnson

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Natural killer (NK) cells discern the health of other cells by recognising the balance of activating and inhibitory ligands expressed by each target cell. However, how the integration of activating and inhibitory signals relates to formation of the NK cell immune synapse remains a central question in our understanding of NK cell recognition. Here we report(More)
Notches — where small changes in behavior lead to large changes in a tax or subsidy — figure prominently in many policies, but have been rarely examined by economists. In this paper, we analyze a class of notches associated with policies aimed at improving vehicle fuel economy. We provide several pieces of evidence showing that automakers respond to notches(More)
This paper sheds light on the nature of labor income risk by exploiting the information contained in the joint dynamics of households'labor earnings and consumption-choice decisions. In particular, this paper attempts to discriminate between two leading views on the nature of labor income risk: the " restricted income pro…les " (RIP) model— in which(More)
[1] We measured the hyporheic residence time distribution in a 2nd-order mountain stream at the H. J. Andrews Experimental Forest, Oregon, and found it to be a power-law over at least 1.5 orders of magnitude in time (1.5 hr to 3.5 d). The residence time distribution has a very long tail which scales as t À1.28 , and is poorly characterized by an exponential(More)
Few preclinical or clinical studies have evaluated the effect of anesthetics on motor evoked potentials (MEPs), either alone or in the presence of conditioning stimuli such as deep brain stimulation (DBS). In this study we evaluated the effects of two commonly used anesthetic agents, propofol and ketamine (KET), on MEPs elicited by intra-cortical(More)
Patients having stereo-electroencephalography (SEEG) electrode, subdural grid or depth electrode implants have a multitude of electrodes implanted in different areas of their brain for the localization of their seizure focus and eloquent areas. After implantation, the patient must remain in the hospital until the pathological area of brain is found and(More)
Accurately measuring the volume of tissue damage in experimental lesion models is crucial to adequately control for the extent and location of the lesion, variables that can dramatically bias the outcome of preclinical studies. Many of the current commonly used techniques for this assessment, such as measuring the lesion volume with primitive software(More)
—Humans often make decisions which maximize an internal utility function. For example, humans often maximize their expected reward when gambling and this is considered as a " rational " decision. However, humans tend to change their betting strategies depending on how they " feel ". If someone has experienced a losing streak, they may " feel " that they are(More)
The U.S. Army has two disparate combat models, Janus and Distributed Interactive Simulation (DIS) based systems. Both facilitate training, tactical development and weapons analysis. However, a major problem is that entities existing in the Janus Combat Model cannot interact with DIS entities. This paper address how to make this interaction possible,(More)
In language, abstract phrasal patterns provide an important source of meaning, but little is known about whether or how such constructions are used to predict upcoming visual scenes. Findings from two fMRI studies indicate that initial exposure to a novel construction allows its semantics to be used for such predictions. Specifically, greater activity in(More)