We address the problem of compiling defeasible theories to Datalog¬ programs. We prove the correctness of this compilation, for the defeasible logic DL(∂||), but the techniques we use apply to many other defeasible logics. Structural properties of DL(∂||) are identified that support efficient implementation and/or approximation of the conclusions of defeasible theories in the logic, compared with other defeasible logics. We also use previously well-studied structural properties of logic programs to adapt to incomplete Datalog¬ implementations.

In this note, we use Kunen’s notion of a signing to establish two theorems about the well-founded semantics of logic programs, in the case where we are interested in only (say) the positive literals of a predicate p that are consequences of the program. The first theorem identifies a class of programs for which the well-founded and Fitting semantics coincide for the positive part of p. The second theorem shows that if a program has a signing, then computing the positive part of p under the well-founded semantics requires the computation of only one part of each predicate. This theorem suggests an analysis for query answering under the well-founded semantics. In the process of proving these results, we use an alternative formulation of the well-founded semantics of logic programs, which might be of independent interest.

Recent technological advances have led to unprecedented amounts of generated data that originate from the Web, sensor networks, and social media. Analytics in terms of defeasible reasoning – for example, for decision making – could provide richer knowledge of the underlying domain. Traditionally, defeasible reasoning has focused on complex knowledge structures over small to medium amounts of data, but recent research efforts have attempted to parallelize the reasoning process over theories with large numbers of facts. Such work has shown that traditional defeasible logics come with overheads that limit scalability. In this work, we design a new logic for defeasible reasoning, thus ensuring scalability by design. We establish several properties of the logic, including its relation to existing defeasible logics. Our experimental results indicate that our approach is indeed scalable and defeasible reasoning can be applied to billions of facts.

The identification of natural bioactive compounds which can prevent the post-weaning growth check and enhance gastrointestinal health in the absence of in-feed medications is an urgent priority for the swine industry. The objective of this experiment was to determine the effects of increasing dietary inclusion levels of laminarin in the first 14 d post-weaning on pig growth performance and weaning associated intestinal dysfunction. At weaning, ninety-six pigs (8·4 (sd 1·09) kg) (meatline boars × (large white × landrace sows)) were blocked by live weight, litter and sex and randomly assigned to: (1) basal diet; (2) basal + 100 parts per million (ppm) laminarin; (3) basal + 200 ppm laminarin and (4) basal + 300 ppm laminarin (three pigs/pen). The appropriate quantity of a laminarin-rich extract (65 % laminarin) was added to the basal diet to achieve the above dietary inclusion levels of laminarin. After 14 d of supplementation, eight pigs from the basal group and the best-performing laminarin group were euthanised for sample collection. The 300 ppm laminarin group was selected as this group had higher ADFI compared with all other groups and higher ADG than the basal group (P < 0·05). Laminarin supplementation increased villus height in the duodenum and jejunum (P < 0·05). Laminarin supplementation increased the expression of SLC2A8/GLUT8 in the duodenum, SLC2A2/GLUT2, SLC2A7/GLUT7, SLC15A1/PEPT1 and FABP2 in the jejunum and SLC16A1/MCT1 in the colon. Laminarin supplementation reduced Enterobacteriaceae numbers in the caecum (P < 0·05) and increased lactobacilli numbers (P < 0·05), total volatile fatty acid concentrations and the molar proportions of butyrate (P < 0·01) in the colon. In conclusion, 300 ppm laminarin from a laminarin-rich extract has potential, as a dietary supplement, to improve performance and prevent post-weaning intestinal dysfunction.

The study examined (a) whether alcohol use subgroups could be identified among African Americans assessed from adolescence through early adulthood, and (b) whether subgroup membership was associated with the interaction between internalizing symptoms and antisocial behavior polygenic risk scores (PRSs) and environmental characteristics (i.e., parental monitoring, community disadvantage). Participants (N = 436) were initially recruited for an elementary school-based prevention trial in a Mid-Atlantic city. Youths reported on the frequency of their past year alcohol use from ages 14–26. DNA was obtained from participants at age 21. Internalizing symptoms and antisocial behavior PRSs were created based on a genome-wide association study (GWAS) conducted by Benke et al. (2014) and Tielbeek et al. (2017), respectively. Parental monitoring and community disadvantage were assessed at age 12. Four classes of past year alcohol use were identified: (a) early-onset, increasing; (b) late-onset, moderate use; (c) low steady; and (d) early-onset, decreasing. In high community disadvantaged settings, participants with a higher internalizing symptoms PRS were more likely to be in the early-onset, decreasing class than the low steady class. When exposed to elevated community disadvantage, participants with a higher antisocial behavior PRS were more likely to be in the early-onset, increasing class than the early-onset, decreasing and late-onset, moderate use classes.

We recently reported an association of offspring educational attainment with polygenic risk scores (PRS) computed on parent’s non-transmitted alleles for educational attainment using the second GWAS meta-analysis article on educational attainment published by the Social Science Genetic Association Consortium. Here we test the replication of these findings using a more powerful PRS from the third GWAS meta-analysis article by the Consortium. Each of the key findings of our previous paper is replicated using this improved PRS (N = 2335 adolescent twins and their genotyped parents). The association of children’s attainment with their own PRS increased substantially with the standardized effect size, moving from β = 0.134, 95% CI = 0.079, 0.188 for EA2, to β = 0.223, 95% CI = 0.169, 0.278, p < .001, for EA3. Parent’s PRS again predicted the socioeconomic status (SES) they provided to their offspring and increased from β = 0.201, 95% CI = 0.147, 0.256 to β = 0.286, 95% CI = 0.239, 0.333. Importantly, the PRS for alleles not transmitted to their offspring — therefore acting via the parenting environment — was increased in effect size from β = 0.058, 95% CI = 0.003, 0.114 to β = 0.067, 95% CI = 0.012, 0.122, p = .016. As previously found, this non-transmitted genetic effect was fully accounted for by parental SES. The findings reinforce the conclusion that genetic effects of parenting are substantial, explain approximately one-third the magnitude of an individual’s own genetic inheritance and are mediated by parental socioeconomic competence.

Intermittent energy restriction (IER) involves short periods of severe energy restriction interspersed with periods of adequate energy intake, and can induce weight loss. Insulin sensitivity is impaired by short-term, complete energy restriction, but the effects of IER are not well known. In randomised order, fourteen lean men (age: 25 (sd 4) years; BMI: 24 (sd 2) kg/m2; body fat: 17 (4) %) consumed 24-h diets providing 100 % (10 441 (sd 812) kJ; energy balance (EB)) or 25 % (2622 (sd 204) kJ; energy restriction (ER)) of estimated energy requirements, followed by an oral glucose tolerance test (OGTT; 75 g of glucose drink) after fasting overnight. Plasma/serum glucose, insulin, NEFA, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP) and fibroblast growth factor 21 (FGF21) were assessed before and after (0 h) each 24-h dietary intervention, and throughout the 2-h OGTT. Homoeostatic model assessment of insulin resistance (HOMA2-IR) assessed the fasted response and incremental AUC (iAUC) or total AUC (tAUC) were calculated during the OGTT. At 0 h, HOMA2-IR was 23 % lower after ER compared with EB (P<0·05). During the OGTT, serum glucose iAUC (P<0·001), serum insulin iAUC (P<0·05) and plasma NEFA tAUC (P<0·01) were greater during ER, but GLP-1 (P=0·161), GIP (P=0·473) and FGF21 (P=0·497) tAUC were similar between trials. These results demonstrate that severe energy restriction acutely impairs postprandial glycaemic control in lean men, despite reducing HOMA2-IR. Chronic intervention studies are required to elucidate the long-term effects of IER on indices of insulin sensitivity, particularly in the absence of weight loss.

There is a paucity of data examining the effect of cutlery size on the microstructure of within-meal eating behaviour or food intake. Therefore, the present studies examined how manipulation of spoon size influenced these eating behaviour measures in lean young men. In study one, subjects ate a semi-solid porridge breakfast ad libitum, until satiation. In study two, subjects ate a standardised amount of porridge, with mean bite size and mean eating rate covertly measured by observation through a one-way mirror. Both studies involved subjects completing a familiarisation visit and two experimental visits, where they ate with a teaspoon (SMALL) or dessert spoon (LARGE), in randomised order. Subjective appetite measures (hunger, fullness, desire to eat and satisfaction) were made before and after meals. In study one, subjects ate 8 % less food when they ate with the SMALL spoon (SMALL 532 (SD 189) g; LARGE 575 (SD 227) g; P=0·006). In study two, mean bite size (SMALL 10·5 (SD 1·3) g; LARGE 13·7 (SD 2·6) g; P<0·001) and eating rate (SMALL 92 (SD 25) g/min; LARGE 108 (SD 29) g/min; P<0·001) were reduced in the SMALL condition. There were no condition or interaction effects for subjective appetite measures. These results suggest that eating with a small spoon decreases ad libitum food intake, possibly via a cascade of effects on within-meal eating microstructure. A small spoon might be a practical strategy for decreasing bite size and eating rate, likely increasing oral processing, and subsequently decreasing food intake, at least in lean young men.

Research on environmental and genetic pathways to complex traits such as educational attainment (EA) is confounded by uncertainty over whether correlations reflect effects of transmitted parental genes, causal family environments, or some, possibly interactive, mixture of both. Thus, an aggregate of thousands of alleles associated with EA (a polygenic risk score; PRS) may tap parental behaviors and home environments promoting EA in the offspring. New methods for unpicking and determining these causal pathways are required. Here, we utilize the fact that parents pass, at random, 50% of their genome to a given offspring to create independent scores for the transmitted alleles (conventional EA PRS) and a parental score based on alleles not transmitted to the offspring (EA VP_PRS). The formal effect of non-transmitted alleles on offspring attainment was tested in 2,333 genotyped twins for whom high-quality measures of EA, assessed at age 17 years, were available, and whose parents were also genotyped. Four key findings were observed. First, the EA PRS and EA VP_PRS were empirically independent, validating the virtual-parent design. Second, in this family-based design, children's own EA PRS significantly predicted their EA (β = 0.15), ruling out stratification confounds as a cause of the association of attainment with the EA PRS. Third, parental EA PRS predicted the SES environment parents provided to offspring (β = 0.20), and parental SES and offspring EA were significantly associated (β = 0.33). This would suggest that the EA PRS is at least as strongly linked to social competence as it is to EA, leading to higher attained SES in parents and, therefore, a higher experienced SES for children. In a full structural equation model taking account of family genetic relatedness across multiple siblings the non-transmitted allele effects were estimated at similar values; but, in this more complex model, confidence intervals included zero. A test using the forthcoming EA3 PRS may clarify this outcome. The virtual-parent method may be applied to clarify causality in other phenotypes where observational evidence suggests parenting may moderate expression of other outcomes, for instance in psychiatry.

Defeasible logics provide several linguistic features to support the expression of defeasible knowledge. There is also a wide variety of such logics, expressing different intuitions about defeasible reasoning. However, the logics can only combine in trivial ways. This limits their usefulness in contexts where different intuitions are at play in different aspects of a problem. In particular, in some legal settings, different actors have different burdens of proof, which might be expressed as reasoning in different defeasible logics. In this paper, we introduce annotated defeasible logic as a flexible formalism permitting multiple forms of defeasibility, and establish some properties of the formalism.

Open forms of global constraints allow the addition of new variables to an argument during the execution of a constraint program. Such forms are needed for difficult constraint programming problems, where problem construction and problem solving are interleaved, and fit naturally within constraint logic programming. However, in general, filtering that is sound for a global constraint can be unsound when the constraint is open. This paper provides a simple characterization, called contractibility, of the constraints, where filtering remains sound when the constraint is open. With this characterization, we can easily determine whether a constraint has this property or not. In the latter case, we can use it to derive a contractible approximation to the constraint. We demonstrate this work on both hard and soft constraints. In the process, we formulate two general classes of soft constraints.

Internalizing symptoms during adolescence and beyond is a major public health concern, particularly because severe symptoms can lead to the diagnosis of a number of serious psychiatric conditions. This study utilizes a unique sample with a complex statistical method in order to explore Gene × Environment interactions found in internalizing symptoms during adolescence. Data for this study were drawn from a longitudinal prevention intervention study (n = 798) of Baltimore city school children. Internalizing symptom data were collected using self-report and blood or saliva samples genotyped using Affymetrix 6.0 microarrays. A major depression polygenic score was created for each individual using information from the major depressive disorder Psychiatric Genetics Consortium and used as a predictor in a latent trait–state–occasion model. The major depressive disorder polygenic score was a significant predictor of the stable latent trait variable, which captures time-independent phenotypic variability. In addition, an early childhood stressor of death or divorce was a significant predictor of occasion-specific variables. A Gene × Environment interaction was not a significant predictor of the latent trait or occasion variables. These findings support the importance of genetics on the stable latent trait portion of internalizing symptoms across adolescence.

The present study examines the interaction between a polygenic score and an elementary school-based universal preventive intervention trial. The polygenic score reflects the contribution of multiple genes and has been shown in prior research to be predictive of smoking cessation and tobacco use (Uhl et al., 2014). Using data from a longitudinal preventive intervention study, we examined age of first tobacco use from sixth grade to age 18. Genetic data were collected during emerging adulthood and were genotyped using the Affymetrix 6.0 microarray. The polygenic score was computed using these data. Discrete-time survival analysis was employed to test for intervention main and interaction effects with the polygenic score. We found a main effect of the intervention, with the intervention participants reporting their first cigarette smoked at an age significantly later than controls. We also found an Intervention × Polygenic Score interaction, with participants at the higher end of the polygenic score benefitting the most from the intervention in terms of delayed age of first use. These results are consistent with Belsky and colleagues' (e.g., Belsky, Bakermans-Kranenburg, & van IJzendoorn, 2007; Belsky & Pleuss, 2009, 2013; Ellis, Boyce, Belsky, Bakermans-Kranenburg, & van IJzendoorn, 2011) differential susceptibility hypothesis and the concept of “for better or worse,” wherein the expression of genetic variants are optimally realized in the context of an enriched environment, such as provided by a preventive intervention.

This paper describes the system architecture of a newly constructed radio telescope – the Boolardy engineering test array, which is a prototype of the Australian square kilometre array pathfinder telescope. Phased array feed technology is used to form multiple simultaneous beams per antenna, providing astronomers with unprecedented survey speed. The test array described here is a six-antenna interferometer, fitted with prototype signal processing hardware capable of forming at least nine dual-polarisation beams simultaneously, allowing several square degrees to be imaged in a single pointed observation. The main purpose of the test array is to develop beamforming and wide-field calibration methods for use with the full telescope, but it will also be capable of limited early science demonstrations.