Current effects and consequences of tracking

Tracking and ability grouping have long been controversial topics in American education. Researchers have been collecting data on their effects for almost three quarters of a century and still disagree about their merits (Kulik and Kulik, 1987). Educators and policy makers have argued about the effects of ability grouping and tracking for an even longer time. Reviewers of research cannot reach an agreement about the value of homogeneous grouping, yet in 1985 it was determined that in 77 percent of all American schools, ability grouping and tracking were practiced to some degree (Dawson, 1987)

Ecological divergence of Chaetopteryx rugulosa species complex (Insecta, Trichoptera) linked to climatic niche diversification

Climate is often considered to be an important, but indirect driver of speciation. Indeed, environmental factors may contribute to the formation of biodiversity, but to date this crucial relationship remains largely unexplored. Here we investigate the possible role of climate, geological factors, and biogeographical processes in the formation of a freshwater insect species group, the Chaetopteryx rugulosa species complex (Trichoptera) in the Western Balkans. We used multi-locus DNA sequence data to establish a dated phylogenetic hypothesis for the group. The comparison of the dated phylogeny with the geological history of the Western Balkans shows that lineage formation coincided with major past Earth surface and climatic events in the region. By reconstructing present-day habitat conditions (climate, bedrock geology), we show that the lineages of C. rugulosa species complex have distinct climatic but not bedrock geological niches. Without exception, all splits associated with Pliocene/Pleistocene transition led to independent, parallel split into ‘warm’ and ‘cold’ sister lineages. This indicates a non-random diversification on the C. rugulosa species complex associated with late Pliocene climate in the region. We interpreted the results as the diversification of the species complex were mainly driven by ecological diversification linked to past climate change, along with geographical isolation

Processing of Special Metal for Hanford

The object of this project is to reduce the impurities and raise the density of rejected slugs and briquetted turnings from these slugs by recasting the material. Summary and conclusions are (1) slugs and briquettes made from turnings produced when these slugs were machined can be recast with great improvement in quality; (2) casting this material is quite hard on graphite crucibles, but a long-range program might point the way to better graphite usage; (3) this metal run alone gives fair yields (88.8% to 94.8%) if heated to 2500 F and then cooled to 2400 F before pouring. Mixing with virgin metal improves the final quality, but does not materially increase the yield; (4) briquettes should not be mixed with magnesium before recasting

Comparing The Performance, Workload, And Usability Of A Gamepad And Joystick In A Complex Task

Complex human system interface systems such as unmanned vehicles utilize controls that range from standard joystick and keyboard interfaces to Xbox controllers. However, few research studies have been conducted to compare Xbox controllers with other types of interfaces, showing mixed results between those controllers. The current study compared the performance of a joystick and keyboard interface with that of an Xbox controller in both a low and high difficulty task. The results indicate that the Xbox controller had lower tracking errors and trended to lower workload and a slightly higher usability score as measured by the system usability scale (SUS). An interaction between difficulty and controller was not found, however allowing for a longer practice time with the interfaces may have shown significant differences which are planned in a future study. Overall these results indicate favorable results that an Xbox controller may be a viable control interface for complex human system interaction tasks. Copyright 2013 by Human Factors and Ergonomics Society, Inc

Evaluating Input Device Usability As A Function Of Task Difficulty In A Tracking Task

Game controllers are emerging as a preferred choice for the manual control of unmanned vehicles, but an understanding of their usability characteristics has yet to emerge. We compared the usability of an Xbox 360 game controller in a dual task situation using MATB II to the traditional joystick and keyboard interface in two experiments. In the first experiment, performance with the game controller was associated with fewer tracking errors. In a second experiment, we trained users on the devices, and found that even after training the game controller was still associated with fewer tracking errors as well as higher usability and lower workload ratings. These results are consistent with the idea that game controllers are highly usable input devices and do not require high mental workload to operate, thus making them suitable for complex control tasks

Design Considerations To Improve Cognitive Ergonomic Issues Of Unmanned Vehicle Interfaces Utilizing Video Game Controllers

This study was designed to empirically examine the effects of iPod device and text-messaging activities on driver distraction. Sixty participants were asked to perform a driving simulation task while searching for songs using an iPod device or text messaging. Driving errors as measured by lane deviations were recorded and analyzed as a function of the distracters. Physiological measures (EEG) were also recorded during the driving phases in order to measure participant levels of cortical arousal. It was hypothesized that iPod use and text messaging would result in a profound effect on driving ability. The results showed a significant effect of iPod use and text-messaging on driving performance. Increased numbers of driving errors were recorded during the iPod and text-messaging phases than the pre- and post-allocation phases. Higher levels of Theta activity were also observed during the iPod and Text-messaging phase than the pre- and post-allocation phases. Implications for in-vehicle systems design, training, and safety are also discussed. © 2012 - IOS Press and the authors. All rights reserved

Heterogeneous Knowledge Distribution In Mmo Player Behavior: Using Domain Knowledge To Distinguish Membership In A Community Of Practice

Current examinations of expertise in the Massively Multiplayer Online (MMO) domain focus primarily on player performance; explorations of player knowledge, however, have the opportunity to meaningfully supplement these studies. Including player knowledge in MMO studies provides the framework needed for a detailed examination of the role of experience and community membership in defining engaged MMO players within a larger population of potential players. Using the Community of Practice framework, we developed a measure of participant\u27s knowledge of MMO specific language to identify individuals who actively engage with other players, a constantly shifting subpopulation who are meaningfully different than those who are not actively participating. We used membership in a community of practice, as determined by our knowledge assessment, to examine the effectiveness of broader demographic questions and more MMO specific demographic questions in creating a predictive model of membership. Our findings indicate that demographics specific to MMO players are more predictive of membership than those used for a general population. Consequently, we recommend that future studies use knowledge-based measures to identify a subpopulation of engaged MMO players within a larger population, allowing researchers to describe their effects with greater precision

Data from: Epigenetic alterations and decreasing insecticide sensitivity of the Asian tiger mosquito Aedes albopictus

A range of environmental factors, including chemicals, can affect epigenetic processes in organisms leading to variations in phenotype. Thus, epigenetics displays an important environmentally responsive element. The transgenerational impact of environmental stressors on DNA methylation and phenotype was the focus of this study. The influence of two known DNA methylation-changing agents, the phytoestrogen genistein and the fungicide vinclozolin, on the overall DNA methylation level in the Asian tiger mosquito Aedes albopictus was investigated. The experiment comprised four generations in a full life-cycle design with an exposed parental generation and three consecutive non-exposed offspring generations. Application of the methylation agents to the parental generation of the study led to an alteration of the global DNA methylation level of the exposed individuals and those in two subsequent generations. The phenotypic variability of the offspring generations was assessed by examining their insecticide sensitivity. Here, a significant decrease in sensitivity (p<0.01) towards the model insecticide imidacloprid revealed alterations of the mosquito's phenotype in two subsequent generations. Thus, the evaluation of A. albopictus from an epigenetic perspective can contribute important information to the study of the high adaptability of this invasive disease vector to new environments, and its underlying mechanisms

Genomic divergence landscape in recurrently hybridizing Chironomus sister taxa suggests stable steady state between mutual gene flow and isolation

Abstract Divergence is mostly viewed as a progressive process often initiated by selection targeting individual loci, ultimately resulting in ever increasing genomic isolation due to linkage. However, recent studies show that this process may stall at intermediate stable equilibrium states without achieving complete genomic isolation. We tested the extent of genomic isolation between two recurrently hybridizing nonbiting midge sister taxa, Chironomus riparius and Chironomus piger, by analyzing the divergence landscape. Using a principal component‐based method, we estimated that only about 28.44% of the genomes were mutually isolated, whereas the rest was still exchanged. The divergence landscape was fragmented into isolated regions of on average 30 kb, distributed throughout the genome. Selection and divergence time strongly influenced lengths of isolated regions, whereas local recombination rate only had minor impact. Comparison of divergence time distributions obtained from several coalescence‐simulated divergence scenarios with the observed divergence time estimates in an approximate Bayesian computation framework favored a short and concluded divergence event in the past. Most divergence happened during a short time span about 4.5 million generations ago, followed by a stable equilibrium between mutual gene flow through ongoing hybridization for the larger part of the genome and isolation in some regions due to rapid purifying selection of introgression, supported by high effective population sizes and recombination rates. Impact Summary The process of speciation has fascinated biologists from early on. Prevailing theory suggested that gene flow among populations is the main obstacle for their divergence. Recently, it became clear that speciation with gene flow is possible under certain circumstances. However, it remains unclear how the divergence process proceeds in time, how widespread the phenomenon is, and whether it always and inevitably leads to complete isolation. Comparing the genomes of individuals of two regularly hybridizing sister taxa of nonbiting midges, we could show that they diverged during a short period millions of generations ago. Their divergence process apparently ceased before the entire genome was mutually isolated. The taxa remain distinct since, even though they share most of their genome. Our findings thus extend our view of the nature of species and the temporal dynamics of their divergence and describe novel approaches to analyze both current and past divergence processes

Oppold et al. 2015_Figure 2_methylation data

Raw data and statistics of global DNA methylation levels in Aedes albopictus