A Classification of Hyper-heuristic Approaches

The current state of the art in hyper-heuristic research comprises a set of approaches that share the common goal of automating the design and adaptation of heuristic methods to solve hard computational search problems. The main goal is to produce more generally applicable search methodologies. In this chapter we present and overview of previous categorisations of hyper-heuristics and provide a unified classification and definition which captures the work that is being undertaken in this field. We distinguish between two main hyper-heuristic categories: heuristic selection and heuristic generation. Some representative examples of each category are discussed in detail. Our goal is to both clarify the main features of existing techniques and to suggest new directions for hyper-heuristic research

Drying and wetting soil-water retention behaviour of a highly expansive clay under varying initial density

Expansive (or swelling) clays are the most prolific problem soil across Southern Africa and many parts of the world. Large volume changes due to seasonal wetting and drying cause millions of dollars’ worth of damage to engineering infrastructure yearly. Soil-water retention behaviour is dependent ondensity, and determining the correct retention curve may be key for reliable design of infrastructure. Soilwater retention curves and shrinkage curves were measured for recompacted samples of a highly expansive bentonite clay from South Africa. Four samples were prepared at varying initial dry densities between approximately 1200 and 1500 kg/m3 and subjected to total suction testing in a dewpoint hygrometer. The water content of each sample was varied through wetting and drying. The sample volume was measured after each suction reading, allowing relationships between suction and void ratio, degree of saturation and water content to be determined. The relationship between gravimetric water content and suction was not significantly influenced by initial density. Degree of saturation at a given suction varied significantly according to initial density. Volume reductions of 25% to 36% from saturated to residual conditions were recorded, and samples tended to a residual void ratio of 0.35 to 0.4. The swelling clay showed propensity for maintaining high suctions (over 300 MPa at residual conditions) and hysteretic response between primary drying and wetting

Pilot trial of a group cognitive behavioural therapy program for comorbid depression and obesity

Published online: 17 April 2020BACKGROUND: Depression and obesity are significant global health concerns that commonly occur together. An integrated group cognitive behavioural therapy program was therefore developed to simultaneously address comorbid depression and obesity. METHODS: Twenty-four participants (63% women, mean age 46 years) who screened positively for depression with a body mass index ≥25 were recruited from a self-referred general population sample. The group therapy program (10 two-hour weekly sessions) was examined in a single-arm, before-after pilot trial, conducted in a behavioural health clinic in Adelaide, Australia. Primary outcomes included survey and assessment-based analyses of depression, anxiety, body image, self-esteem, and weight (kg), assessed at four time-points: baseline, post-intervention, three-months and 12-months post program. Eighteen participants (75%) completed the program and all assessments. RESULTS: Significant improvements in depression, anxiety, self-esteem and body shape concern scores, several quality of life domains, eating behaviours and total physical activity (among others) - but not weight - were observed over the course of the trial. CONCLUSIONS: Results from this pilot trial suggest that combining interventions for depression and obesity may be useful. Further development of the program, particularly regarding the potential for physical health benefits, and a randomised controlled trial, are warranted. TRIAL REGISTRATION: Trial registration: ANZCTR, ACTRN12617001079336, 13 July 2017. Retrospectively registered after date of the first consent (6 July 2017), but before the date of the first intervention session (20 July 2017).Taryn Lores, Michael Musker, Kathryn Collins, Anne Burke, Seth W. Perry, Ma-Li Wong and Julio Licini

Geometrothermodynamics of black holes

The thermodynamics of black holes is reformulated within the context of the recently developed formalism of geometrothermodynamics. This reformulation is shown to be invariant with respect to Legendre transformations, and to allow several equivalent representations. Legendre invariance allows us to explain a series of contradictory results known in the literature from the use of Weinhold's and Ruppeiner's thermodynamic metrics for black holes. For the Reissner-Nordstr\"om black hole the geometry of the space of equilibrium states is curved, showing a non trivial thermodynamic interaction, and the curvature contains information about critical points and phase transitions. On the contrary, for the Kerr black hole the geometry is flat and does not explain its phase transition structure.Comment: Revised version, to be published in Gen.Rel.Grav.(Mashhoon's Festschrift

Impact of a Prison Therapeutic Diversion Unit on Mental and Behavioral Health Outcomes

Introduction: Incarcerated individuals with mental health disorders are disproportionally sent to restrictive housing (i.e., solitary confinement), which is known to have deleterious impacts on mental health. In response, North Carolina's prison system developed Therapeutic Diversion Units, treatment-oriented units for incarcerated individuals with high mental health needs who cycle in and out of restrictive housing. This analysis compares the impact of restrictive housing and Therapeutic Diversion Units on infractions, mental health, and self-harm among incarcerated individuals. Methods: Data were 2016–2019 incarceration records from North Carolina prisons. Outcomes were rates of infractions, inpatient mental health admissions, and self-harm in restrictive housing and Therapeutic Diversion Units. Inverse probability of treatment weights was used to adjust for confounding, and Poisson regression with generalized estimating equations was used to estimate adjusted rate ratios. Analyses were conducted between January and December 2020. Results: The analytic sample was 3,480 people, of whom 463 enrolled in a Therapeutic Diversion Unit. Compared with Therapeutic Diversion Unit rates, the rate of infractions was 3 times as high in restrictive housing (adjusted rate ratio=2.99, 95% CI=2.31, 3.87), the inpatient mental health admissions rate was 3.5 times as high (adjusted rate ratio=3.57, 95% CI=1.97, 6.46), and the self-injury incident rate was 3.5 times as high (adjusted rate ratio=3.46, 95% CI=2.11, 5.69). Conclusions: Therapeutic Diversion Unit use had strong impacts on infractions, mental health, and self-harm. Therapeutic Diversion Units provide a promising alternative to restrictive housing for individuals with mental health disorders

Fly-by-Pi : open source closed-loop control for geotechnical centrifuge testing applications

Geotechnical centrifuges are valuable instruments for physical modelling of complex geotechnical problems in a controlled laboratory setting. In comparison to full-scale testing, scaled models are cost effective to construct and instrument and, when tested in a geotechnical centrifuge at increased centrifugal accelerations, are capable of replicating full-scale stress–strain soil behaviour. Centrifuge modellers require specialised hardware and instruments capable of functioning under high accelerations. Such hardware is costly, nearly always purpose built, and often rely on commercial, closed-source data acquisition systems, hardware and control systems. This paper demonstrates a novel and versatile, low cost, open source logger and control system that works in parallel alongside existing centrifuge hardware. This solution, termed Fly-by-Pi, was developed using the Raspberry Pi microcomputer. The system provides closed-loop control of linear actuators with the ability to operate in either cyclic, monotonic, or static load- or displacement-control. The control mechanism can be reprogrammed according to experimental requirements, even during flight in the centrifuge. Three independent experiments are described which included the Fly-by-Pi controller as a key component in their operation. Based on the experience gained during these experiments, the authors encourage wide-spread adoption of open-sourced hardware solutions in extreme testing environments.The UK Engineering and Physical Sciences Research Council (EPSRC) Global Challenges Fund under the Wind Africa project.http://www.elsevier.com/locate/ohxpm2021Civil Engineerin

Variation in seizure risk increases from antiseizure medication withdrawal among patients with well-controlled epilepsy: a pooled analysis

ObjectiveGuidelines suggest considering antiseizure medication (ASM) discontinuation in seizure-free patients with epilepsy. Past work has poorly explored how discontinuation effects vary between patients. We evaluated (1) what factors modify the influence of discontinuation on seizure risk; and (2) the range of seizure risk increase due to discontinuation across low- versus high-risk patients.MethodsWe pooled three datasets including seizure-free patients who did and did not discontinue ASMs. We conducted time-to-first-seizure analyses. First, we evaluated what individual patient factors modified the relative effect of ASM discontinuation on seizure risk via interaction terms. Then, we assessed the distribution of 2-year risk increase as predicted by our adjusted logistic regressions.ResultsWe included 1626 patients, of whom 678 (42%) planned to discontinue all ASMs. The mean predicted 2-year seizure risk was 43% [95% confidence interval (CI) 39%–46%] for discontinuation versus 21% (95% CI 19%–24%) for continuation. The mean 2-year absolute seizure risk increase was 21% (95% CI 18%–26%). No individual interaction term was significant after correcting for multiple comparisons. The median [interquartile range (IQR)] risk increase across patients was 19% (IQR 14%–24%; range 7%–37%). Results were unchanged when restricting analyses to only the two RCTs.SignificanceNo single patient factor significantly modified the influence of discontinuation on seizure risk, although we captured how absolute risk increases change for patients that are at low versus high risk. Patients should likely continue ASMs if even a 7% 2-year increase in the chance of any more seizures would be too much and should likely discontinue ASMs if even a 37% risk increase would be too little. In between these extremes, individualized risk calculation and a careful understanding of patient preferences are critical. Future work will further develop a two-armed individualized seizure risk calculator and contextualize seizure risk thresholds below which to consider discontinuation.Plain Language SummaryUnderstanding how much antiseizure medications (ASMs) decrease seizure risk is an important part of determining which patients with epilepsy should be treated, especially for patients who have not had a seizure in a while. We found that there was a wide range in the amount that ASM discontinuation increases seizure risk—between 7% and 37%. We found that no single patient factor modified that amount. Understanding what a patient's seizure risk might be if they discontinued versus continued ASM treatment is critical to making informed decisions about whether the benefit of treatment outweighs the downsides.Paroxysmal Cerebral Disorder

Quantum Vacuum Experiments Using High Intensity Lasers

The quantum vacuum constitutes a fascinating medium of study, in particular since near-future laser facilities will be able to probe the nonlinear nature of this vacuum. There has been a large number of proposed tests of the low-energy, high intensity regime of quantum electrodynamics (QED) where the nonlinear aspects of the electromagnetic vacuum comes into play, and we will here give a short description of some of these. Such studies can shed light, not only on the validity of QED, but also on certain aspects of nonperturbative effects, and thus also give insights for quantum field theories in general.Comment: 9 pages, 8 figur

Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt{s} = 1.96 TeV using Kinematic Characteristics of Lepton + Jets Events

We present a measurement of the top quark pair ttbar production cross section in ppbar collisions at a center-of-mass energy of 1.96 TeV using 230 pb**{-1} of data collected by the DO detector at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), large missing transverse energy, and at least four jets, and extract the ttbar content of the sample based on the kinematic characteristics of the events. For a top quark mass of 175 GeV, we measure sigma(ttbar) = 6.7 {+1.4-1.3} (stat) {+1.6- 1.1} (syst) +/-0.4 (lumi) pb, in good agreement with the standard model prediction.Comment: submitted to Phys.Rev.Let

Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Lepton + Jets Events with Lifetime b-tagging

We present a measurement of the top quark pair ($t\bar{t}$) production cross section ($\sigma_{t\bar{t}}$) in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV using 230 pb$^{-1}$ of data collected by the D0 experiment at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), missing transverse energy, and jets in the final state. We employ lifetime-based b-jet identification techniques to further enhance the $t\bar{t}$ purity of the selected sample. For a top quark mass of 175 GeV, we measure $\sigma_{t\bar{t}}=8.6^{+1.6}_{-1.5}(stat.+syst.)\pm 0.6(lumi.)$ pb, in agreement with the standard model expectation.Comment: 7 pages, 2 figures, 3 tables Submitted to Phys.Rev.Let