Modeling Graph Languages with Grammars Extracted via Tree Decompositions

Work on probabilistic models of natural language tends to focus on strings and trees, but there is increasing interest in more general graph-shaped structures since they seem to be better suited for representing natural language semantics, ontologies, or other varieties of knowledge structures. However, while there are relatively simple approaches to defining generative models over strings and trees, it has proven more challenging for more general graphs. This paper describes a natural generalization of the n-gram to graphs, making use of Hyperedge Replacement Grammars to define generative models of graph languages.9 page(s

A PHOTOGRAMMETRIC WORKFLOW FOR RAPID SITE DOCUMENTATION AT STOBI, REPUBLIC OF NORTH MACEDONIA

The so-called “Theodosian Palace” is one of the most significant Late Antique structures at the site of Stobi, in the Republic of North Macedonia. Popularly thought to be a stopping-place of Theodosius I on his way through the province of Macedonia Secunda according to the evidence of the Codex Theodosianus, the structure is in dire need of conservation with many of the stone and mortar walls threatening to collapse onto the mosaic floors below. Any conservation effort in the Republic of North Macedonia must produce rigorous documentation before any physical work can take place. The most important and time consuming component of the project preparation are section and elevation drawings documenting each of the walls stone-by-stone, with elevations and scales indicated in a format prescribed by the state. These drawings are usually done manually on graph paper in the field, with the assistance of time-honoured manual tools – the plum-bob and tape-measure –, but this method is enormously time consuming and has considerable of room for error. The present project, begun in 2016 and the subject of this paper, endeavoured to show that new, photogrammetric methods could not only improve the accuracy of these drawings, but also the speed with which they are made. Our results demonstrate an increase in accuracy by an order magnitude, from 3 cm to 3 mm, and an improvement in the time to deliver the final product from an estimated 8 months to 2 months

Formalizing Semantic Parsing with Tree Transducers

This paper introduces tree transducers as a unifying theory for semantic parsing models based on tree transformations. Many existing models use tree transformations, but implement specialized training and smoothing methods, which makes it difficult to modify or extend the models. By connecting to the rich literature on tree automata, we show how semantic parsing models can be developed using completely general estimation methods. We demonstrate the approach by reframing and extending one state-of-the-art model as a tree automaton. Using a variant of the inside-outside algorithm with variational Bayesian estimation, our generative model achieves higher raw accuracy than existing generative and discriminative approaches on a standard data set.10 page(s

A digital intervention for adolescent depression ‘MoodHwb’: mixed-methods feasibility evaluation

Background: Treatment and prevention guidelines highlight the key role of health information and evidence-based psychosocial interventions for adolescent depression. Digital health technologies and psychoeducational interventions have been recommended to help engage young people, provide accurate health information, enhance self-management skills and promote social support. However, few digital psychoeducational interventions for adolescent depression have been robustly developed and evaluated. Objective: We aimed to evaluate the feasibility, acceptability and potential impact of a theory-informed, co-designed digital intervention programme, ‘MoodHwb’. Methods: We used a mixed-methods (quantitative and qualitative) approach to evaluate the programme and the assessment process. Adolescents with or at elevated risk of depression and their parents/carers were recruited from mental health services, school counsellors/nurses and participants from a previous study. They completed questionnaires before and after the programme (to gather views and assess changes in mood, knowledge/attitudes and behaviour), and their Web usage was monitored. A subsample was also interviewed. A focus group was conducted with professionals from health, education, social and youth services/charities. Interview and focus group transcripts were analysed using inductive thematic analysis with NVivo 10. Results: Forty-four young people and 31 parents/carers were recruited, and 36 (82%) young people and 21 (68%) parents/carers completed follow-up questionnaires. Nineteen young people and 12 parents/carers were interviewed. Thirteen professionals from a range of disciplines participated in the focus group. Overall, participants found the intervention engaging, clear, user-friendly, comprehensive and helpful (particularly the ‘self help’ section), and stated it could be integrated into existing services. The findings provided initial support for the intervention programme theory, for example depression literacy improved after using the intervention. Conclusions: Findings from this early-stage evaluation suggest that ‘MoodHwb’ and the assessment process were feasible and acceptable, and that the intervention has potential to be helpful for young people and families/carers as an early intervention programme in health, education, youth and social services/charities. A randomised controlled trial is needed to further evaluate the digital programme

Antecedents of new-onset major depressive disorder in adolescence: a longitudinal familial high-risk study

Importance: Early-onset major depressive disorder (MDD) is common in individuals at high familial risk of depression and is associated with poor long-term mental health, social, and educational outcomes. Objectives: To examine the developmental pathways that lead to first-episode adolescent-onset MDD (incident cases) in those at high familial risk and to postulate a theoretically informed model that enables simultaneous testing of different pathways to incident adolescent-onset MDD composed of contributions from familial/genetic and social risk factors, as well as effects via specific clinical antecedents. Design, Setting, and Participants: This investigation was a 4-year longitudinal study (April 2007 to March 2011) among offspring of depressed parents in the general community. Analyses were conducted between September 1, 2015, and May 27, 2016. Participants were 337 families in whom the index parent (315 mothers and 22 fathers) had experienced at least 2 episodes of MDD (recruited through primary care) and among whom there was a biologically related child in the age range of 9 to 17 years living with the index parent (197 girls and 140 boys with a mean [SD] age of 12.4 [2.0] years) at baseline. Offspring with MDD before the study or at baseline (n = 27), offspring with an episode of MDD that had remitted by follow-up (n = 4), and offspring with missing baseline MDD data (n = 2) were excluded. Ninety-two percent (279 of 304) of families completed the follow-up. Main Outcomes and Measures: The primary outcome was new-onset offspring MDD, and the secondary outcome was the total DSM-IV MDD symptom score. Results: On average, children and adolescents had a mean (SD) of 1.85 (1.74) (range, 0-8.5) DSM-IV symptoms of MDD at follow-up. Twenty (6 males and 14 females) had new-onset MDD, with a mean (SD) age at onset of 14.4 (2.0) years (range, 10-18 years). Irritability (β = 0.12, P = .03) and fear and/or anxiety (β = 0.38, P < .001) were significant independent clinical antecedents of new adolescent-onset MDD, but disruptive behavior (β = −0.08, P = .14) and low mood (β = −0.03, P = .65) were not. The results were similar for the DSM-IV symptom count at follow-up. All the measured familial/genetic and social risk indicators directly influenced risk for new-onset MDD rather than indirectly through acting on dimensional clinical antecedents. Conclusions and Relevance: There are multiple pathways to first-onset adolescent depression in individuals at familial risk. Irritability and fear/anxiety may be additional clinical phenomena to be included as targets in primary preventive interventions focusing on the child. In addition to targeting these phenomena in parents and children, depression prevention methods in high-risk groups may need to take into consideration social risks, such as poverty and psychosocial adversity

Validation of the short Mood and Feelings Questionnaire in young adulthood

BACKGROUND: Depression often onsets in adolescence and is associated with recurrence in adulthood. There is a need to identify and monitor depression symptoms across adolescence and into young adulthood. The short Mood and Feelings Questionnaire (sMFQ) is commonly used to measure depression symptoms in adolescence but has not been validated in young adulthood. This study aimed to (1) examine whether the sMFQ is valid in young adulthood, and (2) identify cut-points best capturing DSM-5 depression diagnosis at age 25 METHODS: The sample included participants in the Avon Longitudinal Study of Parents and Children (ALSPAC) at age 25 (n = 4098). Receiver Operating Characteristic analyses examined how well the self-rated sMFQ discriminates between cases and non-cases of DSM-5 Major Depressive Disorder (MDD) classified using the self-rated Development and Well Being Assessment. Sensitivity and specificity values were used to identify cut-points on the sMFQ RESULTS: The sMFQ had high accuracy for discriminating MDD cases from non-cases at age 25. The commonly used cut-point in adolescence (≥12) performed well at this age, best balancing sensitivity and specificity. However, a lower cut-point (≥10) may be appropriate when favouring sensitivity over specificity e.g., in context of screening. Sensitivity analyses suggested similar results for males and females LIMITATIONS: ALSPAC is a longitudinal population cohort that suffers from non-random attrition CONCLUSIONS: The sMFQ is a valid measure of depression in young adults in the general population. It can be used to screen for and monitor depression across adolescence and early adulthood

Investigating the validity of the Strengths and Difficulties Questionnaire to assess ADHD in young adulthood

Attention Deficit Hyperactivity Disorder (ADHD) symptoms typically onset early and persist into adulthood for many. Robust investigation of symptom continuity and discontinuity requires repeated assessments using the same measure, but research is lacking into whether measures used to assess ADHD symptoms in childhood are also valid in adulthood. The Strengths and Difficulties Questionnaire (SDQ) is widely used to assess ADHD symptoms in children, but little is known about its utility in adulthood. The aim of this study was to assess the validity of the SDQ hyperactivity/ADHD subscale to distinguish between cases and non-cases of DSM-5 ADHD at age 25 years in a UK population cohort (N=4121). ADHD diagnosis was derived using the Barkley Adult ADHD Rating Scale-IV. Analyses suggested that the self-rated SDQ ADHD subscale had high validity in distinguishing ADHD cases/non-cases in young adulthood (area under the curve=0.90, 95% CI=0.87-0.93) and indicated a lower cut-point for identifying those who may have an ADHD diagnosis in this age group compared to that currently recommended for younger ages. Findings were similar for parent-reports. Our findings suggest that the SDQ is suitable for ADHD research across different developmental periods, which will aid the robust investigation of ADHD from childhood to young adulthood

The antecedents and outcomes of persistent and remitting adolescent depressive symptom trajectories:a longitudinal, population-based English study

Background Depression often first emerges in adolescence and, for many, is a lifelong disorder. The long-term clinical course of depression is highly variable. We aimed to examine the adult outcomes of adolescent-onset trajectories of clinically significant depressive symptoms and to identify factors differentiating trajectories that persist and desist in adulthood. Methods We included participants from the English population-based Avon Longitudinal Study of Parents and Children with data on depressive symptoms. Self-reported depression symptoms were assessed on ten occasions when participants were age 10·5–25 years using the short Mood and Feelings Questionnaire, and major depressive disorder episodes were assessed at age 13·0 years, 15·0 years, 17·5 years, and 25·0 years. We characterised trajectories of depression symptoms using latent class growth analysis, for which we required depression data at least once from each of three key phases: ages 10·5–13·5 years; 16·5–18·5 years; and 21–25 years. We examined adult outcomes by assessing lifetime suicidal self-harm and functional impairment at age 24·0 years, and employment, education, and the self-reported Strengths and Difficulties Questionnaire at age 25·0 years. Findings We studied 4234 participants: 2651 (63%) female, 1582 (37%) male, and one individual with missing sex data. The mean age was 10·6 years (SD 0·2) at baseline and 25·8 years (SD 0·5) at the final timepoint. Data on ethnicity were not available in our data set. We identified four depression trajectory classes: adolescent-persistent depression with onset early in adolescence (7%, n≈279), adolescent-limited depression with onset later in adolescence and remittance by adult life (14%, n≈592), adult-increasing depression (25%, n≈1056), and stable-low levels of depression (54%, n≈2307). The adolescent-persistent class was associated with poor adult outcomes for functional impairment (62%), suicidal self-harm (27%), mental health difficulties (25%), and not being in education, employment, or training (16%). Adolescent-limited depression was associated with transient adolescent stress, but by early adulthood functional impairment and mental health difficulties were similar to the stable-low group. Major depressive disorder polygenic score (odds ratio [OR] 1·36, 95% CI 1·04–1·79), adolescent educational attainment (OR 0·47, 0·30–0·74), and any early childhood adversity (OR 2·60, 1·42–4·78), that persisted into adulthood (OR 1·60, 1·38–1·87) distinguished the adolescent-persistent and adolescent-limited groups. Interpretation The future course of adolescent depression can be differentiated by age at onset during adolescence, adolescent academic attainment, early and persistent adversity, and genetic loading. A detailed social and educational history could be helpful in making clinical decisions about the intensity of interventions for young people with clinically elevated depressive symptoms who seek help

Urinary biomarker concentrations of captan, chlormequat, chlorpyrifos and cypermethrin in UK adults and children living near agricultural land

There is limited information on the exposure to pesticides experienced by UK residents living near agricultural land. This study aimed to investigate their pesticide exposure in relation to spray events. Farmers treating crops with captan, chlormequat, chlorpyrifos or cypermethrin provided spray event information. Adults and children residing ≤100 m from sprayed fields provided first-morning void urine samples during and outwith the spray season. Selected samples (1–2 days after a spray event and at other times (background samples)) were analysed and creatinine adjusted. Generalised Linear Mixed Models were used to investigate if urinary biomarkers of these pesticides were elevated after spray events. The final data set for statistical analysis contained 1518 urine samples from 140 participants, consisting of 523 spray event and 995 background samples which were analysed for pesticide urinary biomarkers. For captan and cypermethrin, the proportion of values below the limit of detection was greater than 80%, with no difference between spray event and background samples. For chlormequat and chlorpyrifos, the geometric mean urinary biomarker concentrations following spray events were 15.4 μg/g creatinine and 2.5 μg/g creatinine, respectively, compared with 16.5 μg/g creatinine and 3.0 μg/g creatinine for background samples within the spraying season. Outwith the spraying season, concentrations for chlorpyrifos were the same as those within spraying season backgrounds, but for chlormequat, lower concentrations were observed outwith the spraying season (12.3 μg/g creatinine). Overall, we observed no evidence indicative of additional urinary pesticide biomarker excretion as a result of spray events, suggesting that sources other than local spraying are responsible for the relatively low urinary pesticide biomarkers detected in the study population

Tau Burden and the Functional Connectome in Alzheimer's Disease and Progressive Supranuclear Palsy

Alzheimer’s Disease (AD) and Progressive Supranuclear Palsy (PSP) represent neurodegenerative Tauopathies with predominantly cortical vs subcortical disease burden. In AD, neuropathology and atrophy preferentially affect ‘hub’ brain regions that are densely connected. It was unclear whether hubs are differentially affected by neurodegeneration because they are more likely to receive pathological proteins that propagate trans-neuronally, in a prion-like manner, or whether they are selectively vulnerable due to a lack of local trophic factors, higher metabolic demands, or differential gene expression. We assessed the relationship between Tau burden and brain functional connectivity, by combining in vivo PET imaging using the ligand AV-1451, and graph theoretic measures of resting-state fMRI in 17 patients with AD, 17 patients with PSP, and 12 controls. Strongly connected nodes displayed more Tau pathology in AD, independently of intrinsic connectivity network, validating the predictions of theories of trans-neuronal spread but not supporting a role for metabolic demands or deficient trophic support in Tau accumulation. This was not a compensatory phenomenon, as the functional consequence of increasing Tau burden in AD was a progressive weakening of the connectivity of these same nodes, reducing weighted degree and local efficiency and resulting in weaker ‘small-world’ properties. Conversely, in PSP, unlike in AD, those nodes that accrued pathological Tau were those that displayed graph metric properties associated with increased metabolic demand and a lack of trophic support rather than strong functional connectivity. Together, these findings go some way towards explaining why AD affects large scale connectivity networks throughout cortex while neuropathology in PSP is concentrated in a small number of subcortical structures. Further, we demonstrate that in PSP increasing Tau burden in midbrain and deep nuclei was associated with strengthened cortico-cortical functional connectivity. Disrupted cortico-subcortical and cortico-brainstem interactions meant that information transfer took less direct paths, passing through a larger number of cortical nodes, reducing closeness centrality and eigenvector centrality in PSP, while increasing weighted degree, clustering, betweenness centrality and local efficiency. Our results have wide-ranging implications, from the validation of models of Tau trafficking in humans to understanding the relationship between regional Tau burden and brain functional reorganization.The NIMROD study was funded by the National Institute for Health Research (NIHR, RG64473) Cambridge Biomedical Research Centre and Biomedical Research Unit in Dementia, PSP Association, the Wellcome Trust (JBR 103838), the Medical Research Council (MC-A060-5PQ30). T.E.C. is supported by a personal fellowship from the Association of British Neurologists and Patrick Berthoud charitable trust