The Hudson Laboratories microbarograph system: Results and future trends

The ultralow frequency microbarograph system is described, and some results for periods ranging from a few minutes to a few hours are presented. Problems encountered during operation of the system are also discussed

Helical Magnetorotational Instability in Magnetized Taylor-Couette Flow

Hollerbach and Rudiger have reported a new type of magnetorotational instability (MRI) in magnetized Taylor-Couette flow in the presence of combined axial and azimuthal magnetic fields. The salient advantage of this "helical'' MRI (HMRI) is that marginal instability occurs at arbitrarily low magnetic Reynolds and Lundquist numbers, suggesting that HMRI might be easier to realize than standard MRI (axial field only). We confirm their results, calculate HMRI growth rates, and show that in the resistive limit, HMRI is a weakly destabilized inertial oscillation propagating in a unique direction along the axis. But we report other features of HMRI that make it less attractive for experiments and for resistive astrophysical disks. Growth rates are small and require large axial currents. More fundamentally, instability of highly resistive flow is peculiar to infinitely long or periodic cylinders: finite cylinders with insulating endcaps are shown to be stable in this limit. Also, keplerian rotation profiles are stable in the resistive limit regardless of axial boundary conditions. Nevertheless, the addition of toroidal field lowers thresholds for instability even in finite cylinders.Comment: 16 pages, 2 figures, 1 table, submitted to PR

Research Is a Partner in Forward Focused Time

The complexities of modern society and the dynamic forces of progress necessitate that professionals in every discipline be forward-focused, which is believed to come from gaining higher education. This is becoming standard within the fire and emergency services professions and is commonly a factor regarding upward mobility. With that in mind, the U.S. Fire Administration/National Fire Academy (NFA) developed the Fire and Emergency Services Higher Education (FESHE) recognition certificate

Interactive 3-D Software in Aircraft Rescue and Fire Fighting Training

As the nexus between aviation, fire science, and emergency management becomes increasingly more complex, technology can be used to augment training and avoid risk while maintaining authenticity with situational reality. In Aircraft Rescue & Fire Fighting (ARFF), the manner in which the learning content is effectively imparted to the student-professional can make all the difference in a successful emergency response. The interactive 3-D software developed exclusively for Dallas/Fort Worth Fire Training Research Center (DFW FTRC) is part of a curriculum designed to educated and train ARFF professionals in life-saving strategies and tactics. Through a 2013 Memorandum of Understanding, the world’s leading aviation and aerospace university, Embry-Riddle Aeronautical University (ERAU), and DFW FTRC have created a unique partnership for the conduct of research to explore emerging issues in the discipline. Researchers from ERAU designed this collaborative study to examine how effectively the DFW FTRC virtual technology software in the classroom translated knowledge and accelerated haptic skill transfer to the hands-on portion of ARFF training at the facility. The qualitative approach integrated classroom observations with key informant interviews to create a single-case study exploratory research strategy. Emergent themes led to a richer understanding of experiential learning, particularly key differences among individual student characteristics and instructional culture that influence student proficiency and attitudes. Most noteworthy were: a larger interest among international over domestic students, age/generational difficulties with new technology, and an apprehension among ARFF professionals to transition from traditional tabletop exercises to virtual reality. Variability also existed within the instructional culture, including inconsistencies of software integration in the classroom, instructor proficiency with the software, and adult and group teaching theories. The study also found that knowledge and accelerated haptic skill transfer were positively associated with the virtual reality software, and that interactive participation and memory reinforcement were supported by the findings. Time required for curriculum development advancing further integration of the software into the training program was a significant administrative and operational challenge. Software recommendations included options that allow scenario-specific applications and variable incident conditions, thus enriching each classroom learning experience. Marketing of this software remains the final task for DFW FTRC, as cost-effective distribution could revolutionize training across public safety. Future research should also evaluate pedagogy to categorize learning constructivism using simulator-based and software-supported education and training. How this may be applied to public safety professions where risk is an inherent part of training is a crucial need in the industry

Learning from Asiana 214--Minimizing Strike/Rollover for Aircraft Rescue and Firefighting

Following the crash of Asiana flight 214 on July 6, 2013, the National Transportation Safety Board (NTSB) provided a recommendation to the Aircraft Rescue & Fire Fighting Working Group (ARFFWG) to develop best practices to avoid strike/rollover of seriously injured or deceased persons in mass casualty situations. This paper summarizes the research process and the technical committee’s conclusions. The qualitative inquiry used participatory research and evaluation from medico-legal professionals and the expert committee comprised of 21 aircraft rescue and firefighting experts. Key informants were complemented by documentary analysis, including FAA Advisory Circulars, regulations, standards, medical and aircraft rescue industry publications. The research provides specific committee recommendations for establishing control zones in the mass casualty environment, using START for triage, surveillance, transportation, training and certification of both ARFF personnel and incident command, and airport emergency planning strategies. A best practice for ARFF personnel, which is a tactical procedure for task prioritization at aircraft crash incidents, is also proposed. The authors suggest future pilot testing for evaluation of these best practices following NTSB’s consent with the committee’s recommendations

Statistical analysis of coherent structures in transitional pipe flow

Numerical and experimental studies of transitional pipe flow have shown the prevalence of coherent flow structures that are dominated by downstream vortices. They attract special attention because they contribute predominantly to the increase of the Reynolds stresses in turbulent flow. In the present study we introduce a convenient detector for these coherent states, calculate the fraction of time the structures appear in the flow, and present a Markov model for the transition between the structures. The fraction of states that show vortical structures exceeds 24% for a Reynolds number of about Re=2200, and it decreases to about 20% for Re=2500. The Markov model for the transition between these states is in good agreement with the observed fraction of states, and in reasonable agreement with the prediction for their persistence. It provides insight into dominant qualitative changes of the flow when increasing the Reynolds number.Comment: 11 pages, 26 (sub)figure

Representational ethical model calibration

Equity is widely held to be fundamental to the ethics of healthcare. In the context of clinical decision-making, it rests on the comparative fidelity of the intelligence – evidence-based or intuitive – guiding the management of each individual patient. Though brought to recent attention by the individuating power of contemporary machine learning, such epistemic equity arises in the context of any decision guidance, whether traditional or innovative. Yet no general framework for its quantification, let alone assurance, currently exists. Here we formulate epistemic equity in terms of model fidelity evaluated over learnt multidimensional representations of identity crafted to maximise the captured diversity of the population, introducing a comprehensive framework for Representational Ethical Model Calibration. We demonstrate the use of the framework on large-scale multimodal data from UK Biobank to derive diverse representations of the population, quantify model performance, and institute responsive remediation. We offer our approach as a principled solution to quantifying and assuring epistemic equity in healthcare, with applications across the research, clinical, and regulatory domains

Usage analysis of public AC chargers in the UK

In the United Kingdom, approximately 56% of the total charging network, consisting of forty thousand charge points, is comprised of fast AC chargers. However, there exists a significant lack of information regarding usage patterns, which poses a challenge for making informed decisions about future infrastructure planning. This paper focuses on a statistical analysis of the usage patterns of 416 public AC chargers (7 kW) in the UK, based on a dataset comprising over ten thousand charging sessions. The data was collected from one of the UK's largest AC charging network operators over a four-month period (April to July 2022). The study specifically examines the charging demand (measured in kWh) and utilisation rates of chargers located in four different types of parking lots: multi-storey, workplace, on-street, and surface car parks. The analysis reveals that the median charging demand remains consistent across different locations, but there is a high standard deviation in locations with parking restrictions. Two different utilisation metrics, namely sojourn-based and energy-based, are employed to assess the utilisation rates. The results indicate that the overall median utilization rates are generally low, with most locations recording rates below 5%. These findings contribute valuable insights for effective planning and optimal allocation of investments aimed at expanding charging infrastructure

De novo origins of multicellularity in response to predation

The transition from unicellular to multicellular life was one of a few major events in the history of life that created new opportunities for more complex biological systems to evolve. Predation is hypothesized as one selective pressure that may have driven the evolution of multicellularity. Here we show that de novo origins of simple multicellularity can evolve in response to predation. We subjected outcrossed populations of the unicellular green alga Chlamydomonas reinhardtii to selection by the filter-feeding predator Paramecium tetraurelia. Two of five experimental populations evolved multicellular structures not observed in unselected control populations within ~750 asexual generations. Considerable variation exists in the evolved multicellular life cycles, with both cell number and propagule size varying among isolates. Survival assays show that evolved multicellular traits provide effective protection against predation. These results support the hypothesis that selection imposed by predators may have played a role in some origins of multicellularity

Synthesis of CdS and CdSe nanocrystallites using a novel single-molecule precursors approach

The synthesis of CdS and CdSe nanocrystallites using the thermolysis of several dithioor diselenocarbamato complexes of cadmium in trioctylphosphine oxide (TOPO) is reported. The nanodispersed materials obtained show quantum size effects in their optical spectra and exhibit near band-edge luminescence. The influence of experimental parameters on the properties of the nanocrystallites is discussed. HRTEM images of these materials show well-defined, crystalline nanosized particles. Standard size fractionation procedures can be performed in order to narrow the size dispersion of the samples. The TOPO-capped CdS and CdSe nanocrystallites and simple organic bridging ligands, such as 2,2¢-bipyrimidine, are used as the starting materials for the preparation of novel nanocomposites. The optical properties shown by these new nanocomposites are compared with those of the starting nanodispersed materials