Charge Violation and Alice Behavior in Global and Textured Strings

Spontaneous breaking of global symmetries can produce ``Alice'' strings: line defects which make unbroken symmetries multivalued, induce apparent charge violation via Aharonov-Bohm interactions, and form point defects when twisted into loops. We demonstrate this behavior for both divergent and textured global Alice strings. Both adiabatically scatter charged particles via effective Wilson lines. For textured Alice strings, such Wilson lines occur at all radii, and are multivalued only inside the string. This produces measurable effects, including path-dependent charge violation.Comment: 32 pages, 2 epsfigs, Revte

Mechanisms of fragmentation of Al-W granular composites under dynamic loading

Numerical simulations of Aluminum (Al) and Tungsten (W) granular composite rings under various dynamic loading conditions caused by explosive loading were examined. Three competing mechanisms of fragmentation were observed: a continuum level mechanism generating large macrocracks described by the Grady-Kipp fragmentation mechanism, a mesoscale mechanism generating voids and microcracks near the initially unbonded Al/W interfaces due to tensile strains, and a mesoscale jetting due to the development of large velocity gradients between the W particles and adjacent Al. These mesoscale mechanisms can be used to tailor the size of the fragments by selecting an appropriate initial mesostructure for a given loading condition.Comment: 10 pages, 3 figures, submitted to AP

Observations of cosmic ray induced phosphenes

Phosphene observations by astronauts on flights near and far from earth atmosphere are discussed. It was concluded that phosphenes could be observed by the naked eye. Further investigation is proposed to determine realistic human tolerance levels for extended missions and to evaluate the need to provide special spacecraft shielding

The Conformal Anomaly in General Rank 1 Symmetric Spaces and Associated Operator Product

We compute the one-loop effective action and the conformal anomaly associated with the product $\bigotimes_p{\cal L}_p$ of the Laplace type operators ${\cal L}_p, p=1,2$, acting in irreducible rank 1 symmetric spaces of non-compact type. The explicit form of the zeta functions and the conformal anomaly of the stress-energy momentum tensor is derived.Comment: 10 pages, LaTe

Silo Music and Silo Quake: Granular Flow Induced Vibration

Acceleration and sound measurements during granular discharge from silos are used to show that silo music is a sound resonance produced by silo quake. The latter is produced by stick-slip friction between the wall and the granular material in tall narrow silos. For the discharge rates studied, the occurrence and frequency of flow pulsations are determined primarily by the surface properties of the granular material and the silo wall. The measurements show that the pulsating motion of the granular material drives the oscillatory motion of the silo and the occurrence of silo quake does not require a resonant interaction between the silo and the granular material.Comment: 16 pages, submitted to Powder Technolog

Normal, Abby Normal, Prefix Normal

A prefix normal word is a binary word with the property that no substring has more 1s than the prefix of the same length. This class of words is important in the context of binary jumbled pattern matching. In this paper we present results about the number $pnw(n)$ of prefix normal words of length $n$, showing that $pnw(n) =\Omega\left(2^{n - c\sqrt{n\ln n}}\right)$ for some $c$ and $pnw(n) = O \left(\frac{2^n (\ln n)^2}{n}\right)$. We introduce efficient algorithms for testing the prefix normal property and a "mechanical algorithm" for computing prefix normal forms. We also include games which can be played with prefix normal words. In these games Alice wishes to stay normal but Bob wants to drive her "abnormal" -- we discuss which parameter settings allow Alice to succeed.Comment: Accepted at FUN '1

Parenting Strategies Used by Parents of Children with ASD: Differential Links with Child Problem Behaviour

Here, we explored the structure of the ‘Parenting Strategies Questionnaire’, a new scale designed to measure parenting strategies for problem behaviour in ASD. We then examined links between child behaviour and parenting in a sample of 222 predominantly-UK parents of ASD children exhibiting behaviour found difficult or challenging. Analysis revealed three parenting subscales: Accommodation, Reinforcement Approaches and Reducing Uncertainty. Both Accommodation and Reducing Uncertainty were linked to child problem behaviour. Child factors explained up to 29% of the variance in Accommodation, with Socially Inflexible Non-compliance the strongest predictor, and up to 24% of the variance in Reducing Uncertainty, with Intolerance of Uncertainty the strongest predictor. Child factors were not related to Reinforcement Approaches. Longitudinal studies investigating these relationships are needed. Autism Spectrum Disorders (ASD) are neurodevelopmental impairments characterised by difficulties with communication, socialisation, and rigid and repetitive behaviours (Americal Psychiatric Association 2013). Problem behaviour (also referred to as ‘behaviour that challenges’ or, in the past, ‘challenging behaviour’) often occurs in children with ASD, and is more severe in ASD than in other clinical populations (e.g., Brereton et al. 2006; Estes et al. 2009). Forms of problem behaviour include oppositionality, failures to comply, destructiveness and explosiveness (e.g., Gadow et al. 2004). These behaviours are thought to reflect a dysregulated emotional state, resulting in outbursts and prolonged emotional reactions (Mazefsky et al. 2018a, b). Problem behaviour may reflect attempts by the child to reduce anxiety or distress by escaping aversive activities, or reactivity reflecting frustration when things are not on their terms (Brewer et al. 2014; Larson 2006). Demands to comply have been identified as a key trigger of reactivity in ASD (Chowdhury et al. 2016). Some individuals appear more reactive to routine demands (e.g., to wash or get dressed), and others to demands in socially challenging or novel situations (e.g., when visiting friends) (Chowdhury et al. 2016). The former ‘demand-specific’ profile resembles accounts of extreme/‘pathological’ demand avoidance (‘PDA’), which describe avoidance of and reactivity to routine demands in children with ASD (Newson et al. 2003). Some accounts of PDA explicitly attribute these behaviours to elevated anxiety and distress in the context of demands (Newson et al. 2003). In contrast, the latter ‘socially inflexible’ profile, may particularly reflect intolerance of uncertainty: the tendency to “react negatively on an emotional, cognitive, and behavioural level to uncertain situations and events” (Buhr and Dugas 2009, p. 216), which characterizes some children with ASD (Boulter et al. 2014; Larson 2006)

Environmental DNA Metabarcoding Detects Mammal use of Stock Tanks and Natural Springs on the Prescott National Forest

Recent research has shown the viability of environmental DNA (eDNA) analysis as a tool for identifying species presence in aquatic ecosystems. However, there is limited research indicating the feasibility of eDNA as a survey tool in water sources such as springs and stock tanks. Because of the scarcity of water in the high desert landscape of Arizona, natural springs and stock tanks are an important water resource. In this study, we examined whether 16S rRNA metabarcoding could detect mammal eDNA in springs and stock tanks in the Prescott National Forest. During summer 2019, we collected and analyzed water samples at eight sites, including five natural springs and three stock tanks. Across all sites, samples resulted in the detection of eight vertebrate species, including one amphibian, the American Bullfrog Lithobates catesbeiana, one bird, the Mallard Anas platyrhynchos, and seven mammal species, including the American Black Bear Ursus americanus, Mule Deer Odocoileus hemionus, and two squirrel species from the Genus Sciurus. However, of the 1.9 million sequences generated during sequencing, 1.85 million sequences belonged to invertebrate species. This suggests amplification of invertebrate eDNA associated with the 16S primers, which may interfere with the detection of vertebrate eDNA sequences in these systems. POSTER PRESENTATION ARIZONA SPACE GRANT AWARD IGNITE AWAR

Role of material properties and mesostructure on dynamic deformation and shear instability in Al-W granular composites

Dynamic experiments with Al-W granular/porous composites revealed qualitatively different behavior with respect to shear localization depending on bonding between Al particles. Two-dimensional numerical modeling was used to explore the mesomechanics of the large strain dynamic deformation in Al-W granular/porous composites and explain the experimentally observed differences in shear localization between composites with various mesostructures. Specifically, the bonding between the Al particles, the porosity, the roles of the relative particle sizes of Al and W, the arrangements of the W particles, and the material properties of Al were investigated using numerical calculations. It was demonstrated in simulations that the bonding between the "soft" Al particles facilitated shear localization as seen in the experiments. Numerical calculations and experiments revealed that the mechanism of the shear localization in granular composites is mainly due to the local high strain flow of "soft" Al around the "rigid" W particles causing localized damage accumulation and subsequent growth of the meso/macro shear bands/cracks. The "rigid" W particles were the major geometrical factor determining the initiation and propagation of "kinked" shear bands in the matrix of "soft" Al particles, leaving some areas free of extensive plastic deformation as observed in experiments and numerical calculations.Comment: 10 pages, 14 figures, submitted to Journal of Applied Physic

Optimising a nonlinear utility function in multi-objective integer programming

In this paper we develop an algorithm to optimise a nonlinear utility function of multiple objectives over the integer efficient set. Our approach is based on identifying and updating bounds on the individual objectives as well as the optimal utility value. This is done using already known solutions, linear programming relaxations, utility function inversion, and integer programming. We develop a general optimisation algorithm for use with k objectives, and we illustrate our approach using a tri-objective integer programming problem.Comment: 11 pages, 2 tables; v3: minor revisions, to appear in Journal of Global Optimizatio