The Predictive utility of the model of multiple identity tracking in air traffic control performance

This paper reports an experiment designed to investigate whether the Model of Multiple Identity Tracking can be use to predict air traffic controller performance in terms of situation awareness. The experiment tests a number of predictions derived from the Model of Multiple Identity Tracking. This model posits that when tracking multiple moving objects, the location of 4-5 objects can be acquired in parallel but the identification of any one target needs serial attention. While one object is being identified, an error factor associated with the location of all other objects increases with respect to an objects speed and the amount of time since the object\u27s location-identity binding was refreshed. On an individual basis, working memory limits the number location-identity bindings that be stored at any one time and long term memory makes familiar objects easier to track. The experimental task consisted of tracking a set of moving objects for twenty seconds. The objects were 6-character strings; three letters followed by three numbers. After tracking the objects for twenty seconds, the participant was instructed to locate a target-objects. The time required to find the target object was recorded. The number of objects and the magnitude of direction changes (entropy) were manipulated. The main effect of number of objects was found to be significant. The main effect of entropy was found to be marginally significant. The pattern of results supports the idea that the Model of Multiple Identity Tracking (MOMIT) can be used to predict air traffic controller performance. A formula derived from MOMIT to predict completion time showed a good fit to the experimental data

Metabolic engineering for butanol yield enhancement in Clostridium acetobutylicum

Clostridium acetobutylicum is the model solventogenic saccharolytic Clostridium spp. representing a group of bacteria which exclusively produce acetone and n-butanol along with the common solvent, ethanol; known as the ABE pathway. There is broad utility for n-butanol, particularly as a transport fuel but also as an industrial solvent and as a platform chemical. Hydrogen is also a major product of this organism by way of reduction of protons via ferredoxin coupled hydrogenase activity, where electron flux to this product is mediated by the oxidation of organic metabolic intermediates by the enzymes pyruvate ferredoxin oxidoreductase (PFOR) and the electron bifurcating activity of butyryl-CoA dehydrogenase (BCD). The role of BCD was explored utilising homologous recombination in-frame deletion methods, however, the apparent essentiality of the gene resulted in maintenance of the vector and the target gene in the genome, likely as a result of a random vector integration event. Replacing BCD with trans-2-enoyl-CoA reductase (TER) presents a metabolic engineering opportunity by subversion of electron flux to ferredoxin, and ultimately hydrogen gas production, furthermore, it allows us to investigate the importance of the bifurcating role of BCD. Hypothetically, successful replacement of BCD with TER should result in an alcohologenic fermentation, as the cells attempt to maintain redox cofactor homeostasis. The expression of TER resulted in a significant improvement in solvent productivity. Nevertheless, the electron bifurcating activity of BCD appears to be an essential metabolic function for C. acetobutylicum, and DNA-seq data from a mutant strain obtained from a third party suggests that this is due to the role of hydrogenase in maintaining the proton motive force - in which case a complementary mutation interrupting the function of the proton powered flagella will ultimately facilitate the replacement of BCD with TER. A prototypic lactose inducible orthogonal expression system was applied in order to maximise the flux to butanol in the TER expressing parent strain. A control study using a strain expressing the lactose binding transcriptional activator and the TcdR sigma factor produced an altered phenotype where enhanced solvent production was observed and a computational approach was used to try to identify TcdR promotor binding sites in the C. acetobutylicum genome offering some insight as to the cause of the adjusted phenotype and a new regulator of solventogenesis is proposed

Investigation into Reynolds Number Effects on a Biomimetic Flapping Wing

This research investigated the behavior of a Manduca sexta inspired biomimetic wing as a function of Reynolds number by measuring the aerodynamic forces produced by varying the characteristic wing length and testing at air densities from atmospheric to near vacuum. A six degree of freedom balance was used to measure forces and moments, while high speed cameras were used to measure wing stroke angle. An in-house created graphical user interface was used to vary the voltage of the drive signal sent to the piezoelectric actuator which determined the wing stroke angle. The Air Force Institute of Technology baseline 50 mm wing was compared to wings manufactured with 55, 60, 65, and 70 mm spans, while maintaining a constant aspect ratio. Tests were conducted in a vacuum chamber at air densities between 0.5% and 100% of atmospheric pressure. Increasing the wingspan increased the wing’s weight, which reduced the first natural frequency; and did not result in an increase in vertical force over the baseline 50 mm wing. However, if the decrease in natural frequency corresponding to the increased wing span was counteracted by increasing the thickness of the joint material in the linkage mechanism, vertical force production increased over the baseline wing planform. Of the wings built with the more robust flapping mechanism, the 55 mm wing span produced 95% more vertical force at a 26% higher flapping frequency, while the 70 mm wing span produced 165% more vertical force at a 10% lower frequency than the Air Force Institute of Technology baseline wing. Negligible forces and moments were measured at vacuum, where the wing exhibited predominantly inertial motion, revealing flight forces measured in atmosphere are almost wholly limited to interaction with the surrounding air. Lastly, there was a rough correlation between Reynolds number and vertical force, indicating Reynolds number is a useful modelling parameter to predict lift and corresponding aerodynamic coefficients for a specific wing design

Streamflow response to fire in large catchments of a Mediterranean-climate region using paired-catchment experiments

Understanding post-fire streamflow dynamics in large California catchments is limited by a lack of direct empirical evidence. Scaling results from small experimental catchments to large catchments for practical applications is challenging. We investigated the possibility of using streamflow data from an existing gauge network in central and southern California to examine the effects of fire on streamflow using a paired-catchment approach. Post-fire streamflow change was examined in six paired catchments at annual, seasonal and monthly time-periods. Prediction intervals associated with the pre-fire calibration regression models were used to identify statistically significant changes in post-fire streamflow. The identification of suitable paired test and control catchments presented a major challenge, despite the large number of potential catchments in the network. The best calibration results were associated with catchment pairs that had similar orographic controls over rainfall, with proximity to one another being a secondary control. The effect of fires on streamflow, regardless of time-period examined, was found to be variable, depending mostly on post-fire wetness conditions. No relation was evident between post-fire streamflow change and catchment size or area burnt. Published by Elsevier B.V

Perceptions of Campus Climate by Sexual Minorities

Previous research has indicated that students who identify as lesbian, gay, bisexual, or transgender (LGBT) often have negative experiences on university campuses due to their sexual orientation or gender identity. Direct and indirect experiences contribute to an overall perception of the campus climate. This study used an online survey to assess students’ perceptions of campus climate, their experiences confronting bias, support of family members and friends, and whether they had considered leaving campus. Multiple regression analysis indicated that perceptions of poorer campus climate were predicted by greater unfair treatment by instructors, more impact from anti-lesbian, gay, bisexual, transgender, or queer (LGBTQ) bias on friends’ and families’ emotional support, and having hidden one’s LGBT identity from other students. Cluster analyses revealed four groups of participants distinguished by openness about their sexual orientation and negative experiences, with one group appearing to be at risk for poor retention. Results are discussed in terms of the needs of LGBTQ students on campus

Perceptions of Campus Climate by Sexual Minorities

Previous research has indicated that students who identify as lesbian, gay, bisexual, or transgender (LGBT) often have negative experiences on university campuses due to their sexual orientation or gender identity. Direct and indirect experiences contribute to an overall perception of the campus climate. This study used an online survey to assess students’ perceptions of campus climate, their experiences confronting bias, support of family members and friends, and whether they had considered leaving campus. Multiple regression analysis indicated that perceptions of poorer campus climate were predicted by greater unfair treatment by instructors, more impact from anti-lesbian, gay, bisexual, transgender, or queer (LGBTQ) bias on friends’ and families’ emotional support, and having hidden one’s LGBT identity from other students. Cluster analyses revealed four groups of participants distinguished by openness about their sexual orientation and negative experiences, with one group appearing to be at risk for poor retention. Results are discussed in terms of the needs of LGBTQ students on campus

Functional Nanoparticles in Thin Films as Sensing Media

The combination of unique properties offered by materials on the nanoscale with the increased role of surface chemistry in nanostructured solids makes core-shell nanoparticles extremely attractive for application to smart thin-film coatings. Sensing properties of nanoparticle-based thin films were studied in several systems containing organic-coated semiconductor and metallic particles. In semiconductors, the interaction of organic shell and/or thin-film matrix with the environment results in changes in the nanoparticle\u27s surface states, altering the optical properties of the thin film. Measuring the electrical properties of thin films composed of metallic cores with hydrocarbon shells offers another mechanism to monitor the local environment through the swelling of the hydrocarbons in the presence of external compounds. These mechanisms and their potential application to novel sensors will be discussed