The Effect of Context Switching, Focal Switching Distance, Binocular and Monocular Viewing, and Transient Focal Blur on Human Performance in Optical See-Through Augmented Reality.

In optical see-through augmented reality (AR), information is often distributed between real and virtual contexts, and often appears at different distances from the user. To integrate information, users must repeatedly switch context and change focal distance. If the user's task is conducted under time pressure, they may attempt to integrate information while their eye is still changing focal distance, a phenomenon we term transient focal blur. Previously, Gabbard, Mehra, and Swan (2018) examined these issues, using a text-based visual search task on a one-eye optical see-through AR display. This paper reports an experiment that partially replicates and extends this task on a custom-built AR Haploscope. The experiment examined the effects of context switching, focal switching distance, binocular and monocular viewing, and transient focal blur on task performance and eye fatigue. Context switching increased eye fatigue but did not decrease performance. Increasing focal switching distance increased eye fatigue and decreased performance. Monocular viewing also increased eye fatigue and decreased performance. The transient focal blur effect resulted in additional performance decrements, and is an addition to knowledge about AR user interface design issues.

Predicting carbon and water vapor fluxes using machine learning and novel feature ranking algorithms.

Gap-filling eddy covariance flux data using quantitative approaches has increased over the past decade. Numerous methods have been proposed previously, including look-up table approaches, parametric methods, process-based models, and machine learning. Particularly, the REddyProc package from the Max Planck Institute for Biogeochemistry and ONEFlux package from AmeriFlux have been widely used in many studies. However, there is no consensus regarding the optimal model and feature selection method that could be used for predicting different flux targets (Net Ecosystem Exchange, NEE; or Evapotranspiration -ET), due to the limited systematic comparative research based on the identical site-data. Here, we compared NEE and ET gap-filling/prediction performance of the least-square-based linear model, artificial neural network, random forest (RF), and support vector machine (SVM) using data obtained from four major row-crop and forage agroecosystems located in the subtropical or the climate-transition zones in the US. Additionally, we tested the impacts of different training-testing data partitioning settings, including a 10-fold time-series sequential (10FTS), a 10-fold cross validation (CV) routine with single data point (10FCV), daily (10FCVD), weekly (10FCVW) and monthly (10FCVM) gap length, and a 7/14-day flanking window (FW) approach; and implemented a novel Sliced Inverse Regression-based Recursive Feature Elimination algorithm (SIRRFE). We benchmarked the model performance against REddyProc and ONEFlux-produced results. Our results indicated that accurate NEE and ET prediction models could be systematically constructed using SVM/RF and only a few top informative features. The gap-filling performance of ONEFlux is generally satisfactory (R2 = 0.39-0.71), but results from REddyProc could be very limited or even unreliable in many cases (R2 = 0.01-0.67). Overall, SIRRFE-refined SVM models yielded excellent results for predicting NEE (R2 = 0.46-0.92) and ET (R2 = 0.74-0.91). Finally, the performance of various models was greatly affected by the types of ecosystem, predicting targets, and training algorithms; but was insensitive towards training-testing partitioning. Our research provided more insights into constructing novel gap-filling models and understanding the underlying drivers affecting boundary layer carbon/water fluxes on an ecosystem level.

Recent Advances in the Tissue Culture of American Ginseng (Panax quinquefolius).

The in vitro tissue culture of medicinal plants is considered as a potential source for plant-derived bioactive secondary metabolites. The in vitro tissue culture of American ginseng has wide commercial applications in pharmaceutical, nutraceutical, food, and cosmetic fields with regard to the production of bioactive compounds such as ginsenosides and polysaccharides. This review highlights the recent progress made on different types of tissue culture practices with American ginseng, including callus culture, somatic embryo culture, cell suspension culture, hairy root culture, and adventitious root culture. The tissue culture conditions for inducing ginseng callus, somatic embryos, cell suspension, hairy roots, and adventitious roots were analyzed. In addition, the optimized conditions for increasing the production of ginsenosides and polysaccharides were discussed. This review provides references for the use of modern biotechnology to improve the production of bioactive compounds from American ginseng, as well as references for the development and sustainable utilization of American ginseng resources.

The Impact of Hurricane Irma on Population Density of the Black Salt-Marsh Mosquito, Aedes taeniorhynchus, in Collier County, Florida.

In 2017, the southeastern USA and Caribbean endured an extremely active year for tropical storm and hurricane activity. On September 10, 2017, Hurricane Irma made a 2nd landfall in Florida, striking Collier County-including Naples and Marco Island, FL. Areas affected by Hurricane Irma are abundant in salt-marsh and mangrove swamps, prime habitats for the black salt-marsh mosquito, Aedes taeniorhynchus. Using both human landing rate and Biogents BG-Counter trap data, here we report the year-to-year fluctuations in population density of Ae. taeniorhynchus. In 2017, Collier County experienced a population explosion of Ae. taeniorhynchus, with daily landing rates reaching as high as 150 adult females/2-min period. The following year a dramatic population crash of Ae. taeniorhynchus was observed, representing some of the lowest Ae. taeniorhynchus numbers ever recorded in Collier County. Analysis of human landing rate and trap data following major hurricane strikes, including Hurricane Irma (2017) and Hurricane Wilma (2005), have revealed severe reductions in Ae. taeniorhynchus populations. Because Ae. taeniorhynchus accounts for a large majority of adulticiding missions in the state of Florida, an enhanced understanding of the factors contributing to Ae. taeniorhynchus population dynamics may allow for improved operational planning and decision-making.