Early experiences of computer‐aided assessment and administration when teaching computer programming

This paper describes early experiences with the Ceilidh system currently being piloted at over 30 institutions of higher education. Ceilidh is a course‐management system for teaching computer programming whose core is an auto‐assessment facility. This facility automatically marks students programs from a range of perspectives, and may be used in an iterative manner, enabling students to work towards a target level of attainment. Ceilidh also includes extensive course‐administration and progress‐monitoring facilities, as well as support for other forms of assessment including short‐answer marking and the collation of essays for later hand‐marking. The paper discusses the motivation for developing Ceilidh, outlines its major facilities, then summarizes experiences of developing and actually using it at the coal‐face over three years of teaching

MINDING THE COURT: ENHANCING THE DECISION-MAKING PROCESS

Scientists carefully study how our brain processes information, though judges rarely consider these studies. But this research has great potential significance to judges, who spend much of their time making decisions of great importance to others. Although the study of how the brain processes information is an evolving one, the information now available can help judges to make better decisions. Much of the processing for simple tasks—called reflexive processing—occurs in the background, while most of us solve riddles or math problems through reflective processing, which is deliberate and conscious. The reflective system has a limited capacity, so we operate on a principle of least effort, tending to rely on the reflexive system when possible. To do so, we often use what scientists call schemas, in which characteristics of objects, people, or behaviors coalesce into an easily recognizable pattern (like our ability to tell that a red octagon in the distance is a stop sign). Heuristics are schemas that are based on only part of the information available—letting us make decisions more quickly. But heuristics can be faulty in a variety of ways. And since heuristics (like all schemas) operate in the world of unconscious, reflexive processing, we can easily make errors without recognizing the source of a faulty decision. Anchoring is one of these heuristics: for example, a person is likely to give a higher or lower estimate of damages if a particularly high (or low) figure is introduced early in the process. That number— even if far off the mark—tends to act as an anchor around which later estimates are formed

From strings to coils: Rotational dynamics of DNA-linked colloidal chains

We investigate the dynamical behavior of deformable filaments experimentally using a tunable model system consisting of linked paramagnetic colloidal particles, where the persistence length lp, the contour length lc, and the strength and frequency of the external driving force are controlled. We find that upon forcing by an external magnetic field, a variety of structural and conformational regimes exist. Depending on the competition of forces and torques on the chain, we see classic rigid rotator behavior, as well as dynamically rich wagging, coiling, and folding behavior. Through a combination of experiments, computational models, and theoretical calculations, we are able to observe, classify, and predict these dynamics as a function of the dimensionless Mason and magnetoelastic numbers

Addressing environmental and atmospheric challenges for capturing high-precision thermal infrared data in the field of astro-ecology

Using thermal infrared detectors mounted on drones, and applying techniques from astrophysics, we hope to support the field of conservation ecology by creating an automated pipeline for the detection and identification of certain endangered species and poachers from thermal infrared data. We test part of our system by attempting to detect simulated poachers in the field. Whilst we find that we can detect humans hiding in the field in some types of terrain, we also find several environmental factors that prevent accurate detection, such as ambient heat from the ground, absorption of infrared emission by the atmosphere, obscuring vegetation and spurious sources from the terrain. We discuss the effect of these issues, and potential solutions which will be required for our future vision for a fully automated drone-based global conservation monitoring system.Comment: Published in Proceedings of SPIE Astronomical Telescopes and Instrumentation 2018. 8 pages, 3 figure

Calcite dissolution in sediments of the Ontong-Java Plateau : In situ measurements of pore water O₂ and pH

We present in situ electrode measurements of sediment resistivity, pore water oxygen, and pore water pH from three stations between 2300 and 3000 m depth on the Ontong-Java Plateau in the western equatorial Pacific. One of these stations is also the site of a concurrent benthic chamber incubation experiment [Jahnke et al., 1994]. The pore water oxygen data and a steady state diffusion and reaction model constrain the depth-dependent rate of oxic respiration in the sediments and imply a diffusive flux of oxygen to the sediments of 10-21 μmol cm⁻² yr⁻¹. Given these respiration rates, the pore water pH data cannot be explained without calcite dissolution driven by metabolically produced CO₂. The dissolution necessary to explain the observations, quantified by a statistical approach, is 3.5-6 μmol cm⁻² yr⁻¹, which corresponds to at least 20-40% of the calcite rain to these sediments. Over 65% of the total dissolution is driven by metabolic CO₂. Oxygen fluxes and net calcite dissolution constrained by the electrode data are compatible with the benthic chamber measurements of Jahnke et al. [1994]. The dissolution flux, while a significant part of the early diagenesis of calcite in these sediments, is less than would be predicted by earlier models of dissolution, and Jahnke et al. [1994] probably could not distinguish it from zero with the benthic chamber technique. The dissolution rates found in this study are lower than previous estimates because the respiration reaction is concentrated near the sediment-water interface, and the calcite dissolution rate constants are very small. The statistical evaluation of the pore water pH data and model constrain the calcite dissolution rate constant to 0.005-0.16% d⁻¹, following the general trend of lower values determined by in situ techniques rather than by laboratory results

The Local Nanohertz Gravitational-Wave Landscape From Supermassive Black Hole Binaries

Supermassive black hole binaries (SMBHBs) in the 10 million to 10 billion $M_\odot$ range form in galaxy mergers, and live in galactic nuclei with large and poorly constrained concentrations of gas and stars. There are currently no observations of merging SMBHBs--- it is in fact possible that they stall at their final parsec of separation and never merge. While LIGO has detected high frequency GWs, SMBHBs emit GWs in the nanohertz to millihertz band. This is inaccessible to ground-based interferometers, but possible with Pulsar Timing Arrays (PTAs). Using data from local galaxies in the 2 Micron All-Sky Survey, together with galaxy merger rates from Illustris, we find that there are on average $91\pm7$ sources emitting GWs in the PTA band, and $7\pm2$ binaries which will never merge. Local unresolved SMBHBs can contribute to GW background anisotropy at a level of $\sim20\%$, and if the GW background can be successfully isolated, GWs from at least one local SMBHB can be detected in 10 years.Comment: submitted to Nature Astronomy (reformatted for arXiv

Proliferation Security Initiative \u2714

In September 2013 Deputy Assistant Secretary of Defense for Countering Weapons of Mass Destruction Rebecca Hersman requested that the Naval War College conduct a PSI table top game in May 2014 in conjunction with a meeting of the PSI Operational Experts Group (OEG). It was specifically requested that the game explore critical challenges and opportunities in counter- proliferation interdiction, and identify capacity building tools that may be shared with the broader PSI community

The Role of Action Potential Waveform in Failure of Excitation Contraction Coupling

Excitation contraction coupling (ECC) is the process by which electrical excitation of muscle is converted into force generation. Depolarization of skeletal muscle resting potential contributes to failure of ECC in diseases such as periodic paralysis, ICU acquired weakness and possibly fatigue of muscle during vigorous exercise. When extracellular K+ is raised to depolarize the resting potential, failure of ECC occurs suddenly, over a range of several mV of resting potential. While some studies have hypothesized the sudden failure of ECC is due to all-or-none failure of excitation, other studies suggest failure of excitation is graded. Intracellular recordings of action potentials (APs) in individual fibers during depolarization revealed that APs do not fail in an all-or-none manner. Simultaneous imaging of Ca2+ transients during depolarization revealed failure over a narrow range of resting potentials. An AP property that closely correlated with the sudden failure of the Ca2+ transient was the integral of AP voltage with respect to time. We hypothesize the close correlation is due to the combined dependence on time and voltage of Ca2+ release from the sarcoplasmic reticulum. The quantitative relationships established between resting potential, APs and Ca2+ transients provide the foundation for future studies of depolarization-induced failure of ECC in diseases such as periodic paralysis