Northeast Colorado Extreme Rains Interpreted in a Climate Change Context

The probability for an extreme five-day September rainfall event over northeast Colorado, as was observed in early September 2013, has likely decreased due to climate change

Evaluation of a Tool for Airborne-Managed In-Trail Approach Spacing

The Advanced Terminal Area Approach Spacing (ATAAS) tool uses Automatic Dependent Surveillance-Broadcast aircraft state data to compute a speed command for an ATAAS-equipped aircraft to follow and obtain a required time interval behind another aircraft. The ATAAS tool and candidate operational procedures were tested in a high-fidelity, full mission simulator with active airline subject pilots flying an arrival scenario to obtain pilot perceptions of acceptability and workload for the concept. The aircraft consistently achieved the target spacing interval within 1 s when the ATAAS speed guidance was autothrottle-coupled and a slightly greater (4 - 5 s) but consistent interval with pilot-controlled speed changes. The subject pilots rated the ATAAS workload as similar to one with standard procedures for a nominal Instrument Landing System (ILS) approach. They also rated highly various procedural aspects (including amount of head-down time required). Eyetracker data showed only slight changes in instrument scan patterns for ATAAS versus standard ILS procedures

Combined use of satellite estimates and rain gauge observations to generate high-quality historical rainfall time series over Ethiopia

Climate data are used in a number of applications including climate risk management and adaptation to climate change. However, the availability of climate data, particularly throughout rural Africa, is very limited. Available weather stations are unevenly distributed and mainly located along main roads in cities and towns. This imposes severe limitations to the availability of climate information and services for the rural community where, arguably, these services are needed most. Weather station data also suffer from gaps in the time series. Satellite proxies, particularly satellite rainfall estimate, have been used as alternatives because of their availability even over remote parts of the world. However, satellite rainfall estimates also suffer from a number of critical shortcomings that include heterogeneous time series, short time period of observation, and poor accuracy particularly at higher temporal and spatial resolutions. An attempt is made here to alleviate these problems by combining station measurements with the complete spatial coverage of satellite rainfall estimates. Rain gauge observations are merged with a locally calibrated version of the TAMSAT satellite rainfall estimates to produce over 30-years (1983-todate) of rainfall estimates over Ethiopia at a spatial resolution of 10 km and a ten-daily time scale. This involves quality control of rain gauge data, generating locally calibrated version of the TAMSAT rainfall estimates, and combining these with rain gauge observations from national station network. The infrared-only satellite rainfall estimates produced using a relatively simple TAMSAT algorithm performed as good as or even better than other satellite rainfall products that use passive microwave inputs and more sophisticated algorithms. There is no substantial difference between the gridded-gauge and combined gauge-satellite products over the test area in Ethiopia having a dense station network; however, the combined product exhibits better quality over parts of the country where stations are sparsely distributed

Middle School: Building Persistence

This case study explores the skill of engaging and persisting that Nebraska rural freshmen students possess based on whether an art education class was offered every year of middle school. Data was gathered through multiple student observations, field notes, and student document and artifact analysis. This study emphasizes the critical need for art education at every level, especially in middle school, to ensure the strong development of engaging and persisting essential for high school learning experiences

Causes and Predictability of the 2012 Great Plains Drought

Central Great Plains precipitation deficits during May-August 2012 were the most severe since at least 1895, eclipsing the Dust Bowl summers of 1934 and 1936. Drought developed suddenly in May, following near-normal precipitation during winter and early spring. Its proximate causes were a reduction in atmospheric moisture transport into the Great Plains from the Gulf of Mexico. Processes that generally provide air mass lift and condensation were mostly absent, including a lack of frontal cyclones in late spring followed by suppressed deep convection in summer owing to large-scale subsidence and atmospheric stabilization. Seasonal forecasts did not predict the summer 2012 central Great Plains drought development, which therefore arrived without early warning. Climate simulations and empirical analysis suggest that ocean surface temperatures together with changes in greenhouse gases did not induce a substantial reduction in summertime precipitation over the central Great Plains during 2012. Yet, diagnosis of the retrospective climate simulations also reveals a regime shift toward warmer and drier summertime Great Plains conditions during the recent decade, most probably due to natural decadal variability. As a consequence, the probability for severe summer Great Plains drought may have increased in the last decade compared to the 1980s and 1990s, and the so-called tail-risk for severe drought may have been heightened in summer 2012. Such an extreme drought event was nonetheless still found to be a rare occurrence within the spread of 2012 climate model simulations. Implications of this study's findings for U.S. seasonal drought forecasting are discussed

The Effects of Task Partitioning and Computer Skill Level on Operator Engagement and Performance in an Adaptive Biocybernetic Environment

The present study examined task partitioning in an adaptive environment, utilizing the cybernetic closed-loop system of Pope et al. (1995). In that study, participants either performed a tracking task (manual condition) or monitored the tracking task (automatic condition). Changes in task mode were driven by an engagement index derived from the participant\u27s EEG and operated under either positive or negative feedback conditions. One goal of the present study was to examine participant performance under a wider range of tracking conditions. Specifically, the task was partitioned into 3 modes: a manual mode, a partitioned mode, and an automatic mode. A second objective of the present study was to examine the effects of different skill levels of a computer teammate within the closed-loop system. An index of operator engagement was used as a basis for switching the compensatory tracking task among the three task modes. These three modes were combined factorially with two feedback. conditions (positive and negative) and two skill levels (expert and novice). Performance was assessed by the level of operator engagement index as well as RMSE on the tracking task. In addition, participants provided estimates of subjective workload on the NASA-TLX. Results of the present study showed that more task allocations occurred under negative feedback than positive feedback. Also, a feedback by task mode interaction for mean engagement showed that the biocybernetics system responded exactly as expected in a multi-level situation, supporting Pope et al. (1994, 1995). Participants paired with an expert-level computer outperformed those paired with a novice-level, showing that the effect of skill level of a computer teammate applies in an adaptive environment. Workload estimates, however, did not show significant differences across skill levels. Tracking performance in the partitioned mode may have been affected by the brief amount of time participants had to acclimate to that mode. Future changes to the cybernetic system may require a damping factor to limit the frequency of task allocations, or the use of a wider range around the baseline mean for the switch criterion

SYTO dyes and EvaGreen outperform SYBR Green in real-time PCR

Background: Real-time PCR can be carried out using either probes or DNA dyes. SYBR Green has been used the most, but it suffers from several drawbacks. Numerous other DNA dyes are commercially available, but with limited structural information. Dye behavior in real time PCR is difficult to predict, so empirical data are needed. In the work described here, a panel of 23 different DNA dyes–including green, orange, and red SYTO dyes, EvaGreen, and SYBR Green–were evaluated with respect to their performance in real time PCR. Findings: Data were analyzed for reaction inhibition, effects on amplicon melting temperature, fluorescent signal strength, and reaction efficiency. This is the first report of reaction efficiency using alternatives to SYBR Green. Results indicated substantial variation in performance even within the SYTO dye family. EvaGreen and the SYTO dyes 13, 16, 80, and 82 performed better than SYBR Green in general, and high reaction efficiencies can be achieved using these dyes. Conclusions: Empirical data were generated for 23 DNA dyes. This paper confirms and extends previous findings that among commercially available DNA dyes, EvaGreen and certain SYTO dyes are the most desirable alternatives to the commonly used SYBR Green in real-time PCR. Backgroun

Perceptual Cues and Subjective Organization in a Virtual Information Workspace

The key to effectively using the immense body of data on the Internet is an efficient method of organizing relevant information. Researchers and designers are beginning to promote the advantages of three-dimensional (3D) models of information storage and retrieval; however, the potential benefits of perceptual depth cues have not been systematically studied. The present study used a computer task to examine the effectiveness of three types of virtual desktops. A two-dimensional (2D) virtual desktop display, lacking in the cues that give the illusion of depth, was compared to two different 3D virtual desktops, both of which used perceptual cues to convey a sense of depth. One of the 3D desktop conditions conveyed motion parallax through an automatic rotation. It was expected that performance would increase as the number of perceptual cues increased. The present study also examined the potential benefits of organizing and retrieving documents from a subjectively organized versus a preconstructed, or fixed, information space. An organization that individuals create for their own use may be difficult for others to use. Thus, subjective organization of documents was expected to promote better performance than a fixed organization scheme, which is exactly what the data showed. There was a very strong performance benefit to those who organized their own desktops. Contrary to the other hypothesis, the 2D arrangement was more beneficial to users than either the 3D or 3D with motion arrangements. The 2D advantage may be the result of a number of factors. First, although people live in a 3D world they navigate more on 2D planes. Also, people may naturally encode spatial information in a descriptive or symbolic manner, as opposed to creating a spatial analog in the mind\u27s eye. Designers should not blindly attempt to create interfaces that mimic the real world. The choice between a 2D and 3D interface should be based upon the type of task to which the interface will be applied. Information storage/recall tasks, including the present task, will most likely benefit from a 2D interface. Other tasks that make greater use of navigation in 3D space may be better suited to 3D displays

Snapshots

A collection of photos of Cyclones having fun