The bacterium Escherichia coli O157:H7 is a worldwide threat to public health and has been implicated in many outbreaks of haemorrhagic colitis, some of which included fatalities caused by haemolytic uraemic syndrome. Close to 75,000 cases of O157:H7 infection are now estimated to occur annually in the United States. The severity of disease, the lack of effective treatment and the potential for large-scale outbreaks from contaminated food supplies have propelled intensive research on the pathogenesis and detection of E. coli O157:H7 (ref. 4). Here we have sequenced the genome of E. coli O157:H7 to identify candidate genes responsible for pathogenesis, to develop better methods of strain detection and to advance our understanding of the evolution of E. coli, through comparison with the genome of the non-pathogenic laboratory strain E. coli K-12 (ref. 5). We find that lateral gene transfer is far more extensive than previously anticipated. In fact, 1,387 new genes encoded in strain-specific clusters of diverse sizes were found in O157:H7. These include candidate virulence factors, alternative metabolic capacities, several prophages and other new functions--all of which could be targets for surveillance.

Single molecule approaches offer the promise of large, exquisitely miniature ensembles for the generation of equally large data sets. Although microfluidic devices have previously been designed to manipulate single DNA molecules, many of the functionalities they embody are not applicable to very large DNA molecules, normally extracted from cells. Importantly, such microfluidic devices must work within an integrated system to enable high-throughput biological or biochemical analysis-a key measure of any device aimed at the chemical/biological interface and required if large data sets are to be created for subsequent analysis. The challenge here was to design an integrated microfluidic device to control the deposition or elongation of large DNA molecules (up to millimeters in length), which would serve as a general platform for biological/biochemical analysis to function within an integrated system that included massively parallel data collection and analysis. The approach we took was to use replica molding to construct silastic devices to consistently deposit oriented, elongated DNA molecules onto charged surfaces, creating massive single molecule arrays, which we analyzed for both physical and biochemical insights within an integrated environment that created large data sets. The overall efficacy of this approach was demonstrated by the restriction enzyme mapping and identification of single human genomic DNA molecules.

The American Academy of Pediatrics recommends no screen time for children under the age of 2 and limited screen time for all children. However, no such guidelines have been proposed for preteens and teenagers. Further, research shows that children, preteens, and teenagers are using massive amounts of media and those with more screen time have been shown to have increased obesity, reduced physical activity, and decreased health. This study examined the impact of technology on four areas of ill-being–psychological issues, behavior problems, attention problems and physical health–among children (aged 4–8), preteens (9–12), and teenagers (13–18) by having 1030 parents complete an online, anonymous survey about their own and their child's behaviors. Measures included daily technology use, daily food consumption, daily exercise, and health. Hypothesis 1, which posited that unhealthy eating would predict impaired ill-being, was partially supported, particularly for children and preteens. Hypothesis 2, which posited that reduced physical activity would predict diminished health levels, was partially supported for preteens and supported for teenagers. Hypothesis 3, that increased daily technology use would predict ill-being after factoring out eating habits and physical activity, was supported. For children and preteens, total media consumption predicted illbeing while for preteens specific technology uses, including video gaming and electronic communication, predicted ill-being. For teenagers, nearly every type of technological activity predicted poor health. Practical implications were discussed in terms of setting limits and boundaries on technology use and encouraging healthy eating and physical activity at home and at school.

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Teleporting is a popular interface to allow virtual reality users to explore environments that are larger than the available walking space. When teleporting, the user positions a marker in the virtual environment and is instantly transported without any self-motion cues. Five experiments were designed to evaluate the spatial cognitive consequences of teleporting and to identify environmental cues that could mitigate those costs. Participants performed a triangle completion task by traversing two outbound path legs before pointing to the unmarked path origin. Locomotion was accomplished via walking or two common implementations of the teleporting interface distinguished by the concordance between movement of the body and movement through the virtual environment. In the partially concordant teleporting interface, participants teleported to translate (change position) but turned the body to rotate. In the discordant teleporting interface, participants teleported to translate and rotate. Across all five experiments, discordant teleporting produced larger errors than partially concordant teleporting which produced larger errors than walking, reflecting the importance of translational and rotational selfmotion cues. Furthermore, geometric boundaries (room walls or a fence) were necessary to mitigate the spatial cognitive costs associated with teleporting, and landmarks were helpful only in the context of a geometric boundary. Public Significance Statement: Movement through a virtual environment (VE) can be accomplished by walking, but physical space constraints require a navigation interface. One popular interface is teleporting, whereby the user points to a place in the VE and is instantly transported there. In this study, we reveal that teleporting can lead to spatial disorientation due to lack of self-motion cues. Boundaries in the VE, such as walls or a fence, reduce but do not eliminate the disorienting effect of teleporting.