Encoding monomorphic and polymorphic types

Most automatic theorem provers are restricted to untyped logics, and existing translations from typed logics are bulky or unsound. Recent research proposes monotonicity as a means to remove some clutter. Here we pursue this approach systematically, analysing formally a variety of encodings that further improve on efficiency while retaining soundness and completeness. We extend the approach to rank-1 polymorphism and present alternative schemes that lighten the translation of polymorphic symbols based on the novel notion of “cover”. The new encodings are implemented, and partly proved correct, in Isabelle/HOL. Our evaluation finds them vastly superior to previous schemes

Encoding monomorphic and polymorphic types

Many automatic theorem provers are restricted to untyped logics, and existing translations from typed logics are bulky or unsound. Recent research proposes monotonicity as a means to remove some clutter when translating monomorphic to un-typed first-order logic. Here we pursue this approach systematically, analysing formally a variety of encodings that further improve on efficiency while retaining soundness and completeness. We extend the approach to rank-1 polymorphism and present alternative schemes that lighten the translation of polymorphic symbols based on the novel notion of “cover”. The new encodings are implemented in Isabelle/HOL as part of the Sledgehammer tool. We include informal proofs of soundness and correctness, and have formalized the monomorphic part of this work in Isabelle/HOL. Our evaluation finds the new encodings vastly superior to previous schemes

Quiescience as a mechanism for cyclical hypoxia and acidosis

Tumour tissue characteristically experiences fluctuations in substrate supply. This unstable microenvironment drives constitutive metabolic changes within cellular populations and, ultimately, leads to a more aggressive phenotype. Previously, variations in substrate levels were assumed to occur through oscillations in the hæmodynamics of nearby and distant blood vessels. In this paper we examine an alternative hypothesis, that cycles of metabolite concentrations are also driven by cycles of cellular quiescence and proliferation. Using a mathematical modelling approach, we show that the interdependence between cell cycle and the microenvironment will induce typical cycles with the period of order hours in tumour acidity and oxygenation. As a corollary, this means that the standard assumption of metabolites entering diffusive equilibrium around the tumour is not valid; instead temporal dynamics must be considered

Similarities and Differences In Adolescence-Onset Versus Adulthood-Onset Sexual Abuse Incidents

A sample of males who had first committed sexual offences against children in either adolescence (n= 230; M= 14.0 years, SD= 1.5) or adulthood (n= 280; M= 34.4 years, SD= 11.7) were compared on measures relating to the circumstances of their first known sexual abuse incident. Considerable diversity in the circumstances of these first incidents was observed for both groups. However, adulthood-onset sexual abuse most often occurred following a long-standing familial relationship with a female victim, and in a home setting. The first incident for adolescence-onset offenders also tended to occur in the context of a long-term relationship and against a female child in a home setting, but more commonly against a nonfamilial victim. Adulthood-onset offenders abused older children, were more likely to engage in penetrative sexual behaviors, and went on to abuse over a longer duration than adolescence-onset offenders. Adolescence-onset offences were more likely to be witnessed by a third party. Findings and their implications for prevention are considered from a situational crime prevention perspective. © 2015 Elsevier Ltd

An integrated smart thermo-chemical energy network

Managing the intermittency of renewable sources together with transient (hourly to daily to seasonal) energy demands is one of the principal challenges of delivering a net-zero energy system. Smart multifunctional thermo-chemical energy networks represent an alternative energy network and storage system, a solution based on the distribution of energy via thermo-chemical material rather than thermal energy, gas, fuels or electricity– an option that has scope for integrated short- and long-term energy storage. This is the first research work to realise such a system and demonstrate how it might operate using smart control strategies and how thermo-chemical fluids (TCFs) can be used as a medium for timely energy storage and distribution. The experimental study also describes the effect of steady and variable heat sources on TCF regeneration performance and estimates the potential of thermo-chemical energy networks, which would be particularly beneficial in buildings with high energy consumption for humidity control. This research proves the practicality of the design idea for such a network, which would be governed by centralised control, regenerated by steady or transient heat loads and capable of supplying a variety of demands in an experimental setting. The energy and economic potential of the network were also assessed, identifying temperature and humidity control application scenarios with energy savings of more than 60% compared to conventional operation and payback periods of 6.6–9.7 years

Police officers\u27 perceptions of the challenges involved in internet child exploitation investigation

PurposeThe purpose of this paper is to explore police officers&rsquo; perceptions of the challenges and work stressors of working in Internet Child Exploitation (ICE) investigation.Design/methodology/approachParticipants were a heterogeneous sample of 32 ICE investigators across nine Australian jurisdictions. Officers&rsquo; perceptions of ICE work were elicited via individual, open-ended, anonymous, telephone interviews, which focused on both the nature and impact of work-related stressors and challenges.FindingsThematic analysis revealed that viewing ICE material was not perceived to be a major stressor or particularly traumatic facet of ICE investigation. Rather, the challenges related to three areas; work relationships, workload and resources and the physical environment. Participants also suggested some improvements to their work environment which could reduce the impact of these challenges.Practical implicationsThe stressors identified by ICE investigators in this study place physical, psychological and social restrictions on investigative capacity. Modifications to the workplace environment that facilitate more effective professional collaboration, reduce workload and enhance investigator efficiency and functionality of the physical work environment would likely reduce the potential for harm associated with ICE investigation and improve ICE investigators&rsquo; capacity to perform their role.Originality/valueThis is the first study to use a broad research framework to examine the full range of stressors that ICE investigators face (both organisational and operational). The findings are important for developing comprehensive theories regarding workplace traumatisation as well as holistic intervention models to assist the prevention and management of stress related to ICE investigation.</div

Review on Sampling Methods and Health Impacts of Fine (PM₂.₅, ≤2.5 µm) and Ultrafine (UFP, PM₀.₁, ≤0.1 µm) Particles

Airborne particulate matter (PM) is of great concern in the modern-day atmosphere owing to its association with a variety of health impacts, such as respiratory and cardiovascular diseases. Of the various size fractions of PM, it is the finer fractions that are most harmful to health, in particular ultrafine particles (PM₀.₁; UFPs), with an aerodynamic diameter ≤ 100 nm. The smaller size fractions, of ≤2.5 µm (PM₂.₅; fine particles) and ≤0.1 µm (PM₀.₁; ultrafine particles), have been shown to have numerous linkages to negative health effects; however, their collection/sampling remains challenging. This review paper employed a comprehensive literature review methodology; 200 studies were evaluated based on the rigor of their methodologies, including the validity of experimental designs, data collection methods, and statistical analyses. Studies with robust methodologies were prioritised for inclusion. This review paper critically assesses the health risks associated with fine and ultrafine particles, highlighting vehicular emissions as the most significant source of particulate-related health effects. While coal combustion, diesel exhaust, household wood combustors’ emissions, and Earth’s crust dust also pose health risks, evidence suggests that exposure to particulates from vehicular emissions has the greatest impact on human health due to their widespread distribution and contribution to air pollution-related diseases. This article comprehensively examines current sampling technologies, specifically focusing on the collection and sampling of ultrafine particles (UFP) from ambient air to facilitate toxicological and physiochemical characterisation efforts. This article discusses diverse approaches to collect fine and ultrafine particulates, along with experimental endeavours to assess ultrafine particle concentrations across various microenvironments. Following meticulous evaluation of sampling techniques, high-volume air samplers such as the Chem Vol Model 2400 High Volume Cascade Impactor and low-volume samplers like the Personal Cascade Impactor Sampler (PCIS) emerge as effective methods. These techniques offer advantages in particle size fractionation, collection efficiency, and adaptability to different sampling environments, positioning them as valuable tools for precise characterisation of particulate matter in air quality research and environmental monitoring

Cellular adaptations to hypoxia and acidosis during somatic evolution of breast cancer

Conceptual models of carcinogenesis typically consist of an evolutionary sequence of heritable changes in genes controlling proliferation, apoptosis, and senescence. We propose that these steps are necessary but not sufficient to produce invasive breast cancer because intraductal tumour growth is also constrained by hypoxia and acidosis that develop as cells proliferate into the lumen and away from the underlying vessels. This requires evolution of glycolytic and acid-resistant phenotypes that, we hypothesise, is critical for emergence of invasive cancer. Mathematical models demonstrate severe hypoxia and acidosis in regions of intraductal tumours more than 100 m from the basement membrane. Subsequent evolution of glycolytic and acid-resistant phenotypes leads to invasive proliferation. Multicellular spheroids recapitulating ductal carcinoma in situ (DCIS) microenvironmental conditions demonstrate upregulated glucose transporter 1 (GLUT1) as adaptation to hypoxia followed by growth into normoxic regions in qualitative agreement with model predictions. Clinical specimens of DCIS exhibit periluminal distribution of GLUT-1 and Na+/H+ exchanger (NHE) indicating transcriptional activation by hypoxia and clusters of the same phenotype in the peripheral, presumably normoxic regions similar to the pattern predicted by the models and observed in spheroids. Upregulated GLUT-1 and NHE-1 were observed in microinvasive foci and adjacent intraductal cells. Adaptation to hypoxia and acidosis may represent key events in transition from in situ to invasive cancer

Predicting multiple victim versus single victim sexual abuse: an examination of distal factors and proximal factors associated with the first abuse incident

Official and confidential self-report data on 83 convicted adult male sexual abusers were analysed to examine whether sexual offending progression can be better predicted from distal antecedents, or from proximal antecedents and outcomes associated with the first sexual abuse incident. Fifty-six offenders who sexually abused more than one victim (multiple victim offenders; MVOs) were compared to 27 offenders who sexually abused a single victim only (single victim offenders; SVOs). MVOs were younger at the time of their first sexual abuse incident, and were more likely to first abuse male and non-familial children. With the exception of sexual attraction to male children, no differences were found between the two groups on distal antecedents. Proximal antecedents and outcomes associated with the first sexual abuse incident were significantly related to multiple victim offending. Logistic regression analysis identified the presence of sexual difficulties in the month prior to the first abuse incident, and sexual excitement immediately preceding the first incident, as significant unique predictors. Implications for risk assessment and risk management are discussed, and future research directions proposed

Entrepreneurial capital, social values and Islamic traditions: exploring the growth of women-owned enterprises in Pakistan

Main ArticleThis study seeks to explore the variables contributing to the growth of women-owned enterprises in the Islamic Republic of Pakistan. Based on a previously established multivariate model, it uses two econometric approaches: first classifying variables into predetermined blocks; and second, using the general to specific approach. Statistical analyses and in-depth interviews confirm that women entrepreneurs’ personal resources and social capital have a significant role in their business growth. Further, it reveals that the moral support of immediate family, independent mobility and being allowed to meet with men play a decisive role in the sales and employment growth of women-owned enterprises in an Islamic country such as Pakistan