Micro black holes in the laboratory

The possibility of creating microscopic black holes is one of the most exciting predictions for the LHC, with potentially major consequences for our current understanding of physics. We briefly review the theoretical motivation for micro black hole production, and our understanding of their subsequent evolution. Recent work on modelling the radiation from quantum-gravity-corrected black holes is also discussed

Defining agronomic practices for forage corn production in Saskatchewan

Non-Peer ReviewedForage corn may be an economical and high-quality alternative for winter feeding in Saskatchewan, but the cost of corn production is high compared to other forage crops. To maximize the economic potential of forage corn for feeding, input costs, such as seed and fertilizer, need to be minimized. The existing recommendations for nitrogen application rate and seeding rate for forage corn are based on grain corn production, resulting in relatively high recommended nitrogen application rates. The purpose of this project was to develop and refine seeding and fertility recommendations for corn silage production and to evaluate the cost of production and feed quality of corn silage grown in Saskatchewan. The 3-year study, including the 2016, 2017 and 2018 growing seasons, was located at three short-season sites (Lanigan, Melfort, and Scott) and three long-season sites (Yorkton, Redvers, and Outlook). The hybrids grown at each site were selected based on their corn heat unit rating. At each site, two different seed brands were planted at three target seeding rates with three nitrogen application rates. The total biomass yield was individually measured for each plot and subsamples were collected for forage quality analysis. Based on Year 2 results, there were significant differences in plant populations and biomass yields among the sites and treatments. An economic analysis was conducted to determine if any yield advantage from higher nitrogen and seeding rates are worth the added cost of these inputs

Hydrodynamic optical soliton tunneling

A conceptually new notion of hydrodynamic optical soliton tunneling is introduced in which a dark soliton is incident upon an evolving, broad potential barrier that arises from an appropriate variation of the input signal. The barriers considered include smooth rarefaction waves and highly oscillatory dispersive shock waves. Both the soliton and the barrier satisfy the same one-dimensional defocusing nonlinear Schrodinger (NLS) equation, which admits a convenient dispersive hydrodynamic interpretation. Under the scale separation assumption of nonlinear wave (Whitham) modulation theory, the highly nontrivial nonlinear interaction between the soliton and the evolving hydrodynamic barrier is described in terms of self-similar, simple wave solutions to an asymptotic reduction of the Whitham-NLS partial differential equations. One of the Riemann invariants of the reduced modulation system determines the characteristics of a soliton interacting with a mean flow that results in soliton tunneling or trapping. Another Riemann invariant yields the tunneled soliton's phase shift due to hydrodynamic interaction. Under certain conditions, soliton interaction with hydrodynamic barriers gives rise to new effects that include reversal of the soliton propagation direction and spontaneous soliton cavitation, which further suggest possible methods of dark soliton control in optical fibers

Exploring the effect of simulated Motion Conditions on Task Performance

This thesis explored the effect that four different areas of motion conditioning presented in a motion simulator had on defence-force based task performance. It is produced in conjunction with the Defence Science and Technology Organisation, Land Operations Division, to expand their understanding of how these conditions may affect their personnel. The four conditions are explored are Motion Sickness, Motion Fatigue, Motion Perception and Mental Workload under motion conditions. All studies involved first year psychology students enrolled at the University of Sydney in accordance with the University’s ethical guidelines (2013/388). In the study of Motion Sickness, nausea was shown to have very little detrimental effect on task performance. In long term driving exposure there was a slight negative effect on the reaction time that was linked to motion sickness symptoms. Two styles of driving were researched for Motion Fatigue: boredom and constant motion. The boredom drive was seen to have a slightly negative effect on performance compared to the motion drive. In analysing biomarkers of fatigue relevant to a defence context, the best indicators were respiratory rate and the Root Mean Square of Successive Differences between normal heart beats. In Motion Perception, 6-axes of motion at 3 intensities were tested using Defence force tasks to determine whether any one axis, or a certain intensity, negatively affected performance more than others. Higher errors occurred in the Roll direction. The Pitch direction was the least comfortable for participants. In the final chapter of Mental Workload under motion, increased workload did not have a great impact on performance, although further studies are needed. In an analysis of subjective scales of workload in simple tasks, participants were able to accurately determine their task performance. From a bio-measure perspective, pupil diameter and respiratory rate were found to be the most indicative of changing levels of workload

Genetic predisposition in patients undergoing cardiopulmonary bypass surgery is associated with an increase of inflammatory cytokines

Objective: Cardiopulmonary bypass (CPB) surgery induces a transient rise in pro-inflammatory cytokines typically released by activated monocytes. The E4 variant of apolipoprotein E is a recognized risk factor for atherosclerosis. It has recently been shown that apolipoprotein E affects monocyte functions in vitro and leads to higher levels of median lipoprotein (a) in humans. The aim of the study is to investigate if the E4 genetic variant of apolipoprotein E affects cytokine release after CPB surgery. Methods: 22 patients were operated on with standard coronary artery bypass grafting. Concentrations of interleukin 8 (IL-8) and tumor necrosis factor (TNF-α) were measured by automated Immulite immunoassay at regular intervals within 48 h after surgery. Total apparent cytokine outputs were calculated as area under the curve. Results are expressed as mean±standard deviation and compared by unpaired t-test. Results: In the presented patient population 6 (27%) carried the E4 allele. Sixteen (63%) showed no E4 allele. Mean cross clamp time (CCT) was 56.2±13.5 min versus 55.7±12.1 min and CPB time was 91.8±17.5 versus 93.5±15.7 min. No statistical difference between E4-carriers and E4 non-carriers regarding CCT and CPB was observed. The total amount of IL-8 and TNF-α was higher in patients carrying the E4 genetic variant of apolipoprotein E in comparison to E4 non-carriers (P≪0.08, P≪0.039). Conclusion: The presence of the E4 allele is associated with increased release of IL-8 and TNF-α after CBP surgery. The preoperative determination of E4 in patients undergoing cardiac surgery may lead to additional perioperative measures for the treatment of an increased systemic inflammatory respons

Reply to Rouder (2014) : good frequentist properties raise confidence

Established psychological results have been called into question by demonstrations that statistical significance is easy to achieve, even in the absence of an effect. One often-warned-against practice, choosing when to stop the experiment on the basis of the results, is guaranteed to produce significant results. In response to these demonstrations, Bayes factors have been proposed as an antidote to this practice, because they are invariant with respect to how an experiment was stopped. Should researchers only care about the resulting Bayes factor, without concern for how it was produced? Yu, Sprenger, Thomas, and Dougherty (2014) and Sanborn and Hills (2014) demonstrated that Bayes factors are sometimes strongly influenced by the stopping rules used. However, Rouder (2014) has provided a compelling demonstration that despite this influence, the evidence supplied by Bayes factors remains correct. Here we address why the ability to influence Bayes factors should still matter to researchers, despite the correctness of the evidence. We argue that good frequentist properties mean that results will more often agree with researchers’ statistical intuitions, and good frequentist properties control the number of studies that will later be refuted. Both help raise confidence in psychological results

Complexity, transparency and time pressure: practical insights into science communication in times of crisis

A global crisis such as the COVID-19 pandemic that started in early 2020 poses significant challenges for how research is conducted and communicated. We present four case studies from the perspective of an interdisciplinary research institution that switched to “corona-mode” during the first two months of the crisis, focussing all its capacities on COVID-19-related issues, communicating to the public directly and via media, as well as actively advising the national government. The case studies highlight the challenges posed by the increased time pressure, high demand for transparency, and communication of complexity and uncertainty. The article gives insights into how these challenges were addressed in our research institution and how science communication in general can be managed during a crisis