Household occupancy and burglary: A case study using COVID-19 restrictions

INTRODUCTION: In response to COVID-19, governments imposed various restrictions on movement and activities. According to the routine activity perspective, these should alter where crime occurs. For burglary, greater household occupancy should increase guardianship against residential burglaries, particularly during the day considering factors such as working from home. Conversely, there should be less eyes on the street to protect against non-residential burglaries. METHODS: In this paper, we test these expectations using a spatio-temporal model with crime and Google Community Mobility data. RESULTS: As expected, burglary declined during the pandemic and restrictions. Different types of burglary were, however, affected differently but largely consistent with theoretical expectation. Residential and attempted residential burglaries both decreased significantly. This was particularly the case during the day for completed residential burglaries. Moreover, while changes were coincident with the timing and relaxation of restrictions, they were better explained by fluctuations in household occupancy. However, while there were significant decreases in non-residential and attempted non-residential burglary, these did not appear to be related to changes to activity patterns, but rather the lockdown phase. CONCLUSIONS: From a theoretical perspective, the results generally provide further support for routine activity perspective. From a practical perspective, they suggest considerations for anticipating future burglary trends

Defect filtering for thermal expansion induced dislocations in III-V lasers on silicon

Epitaxially integrated III-V semiconductor lasers for silicon photonics have the potential to dramatically transform information networks, but currently, dislocations limit performance and reliability even in defect tolerant InAs quantum dot (QD) based lasers. Despite being below critical thickness, QD layers in these devices contain previously unexplained misfit dislocations, which facilitate non-radiative recombination. We demonstrate here that these misfit dislocations form during post-growth cooldown due to the combined effects of (1) thermal-expansion mismatch between the III-V layers and silicon and (2) precipitate and alloy hardening in the active region. By incorporating an additional sub-critical thickness, indium-alloyed misfit dislocation trapping layer, we leverage these mechanical hardening effects to our advantage, successfully displacing 95% of misfit dislocations from the QD layer in model structures. Unlike conventional dislocation mitigation strategies, the trapping layer reduces neither the number of threading dislocations nor the number of misfit dislocations. It simply shifts the position of misfit dislocations away from the QD layer, reducing the defects' impact on luminescence. In full lasers, adding a misfit dislocation trapping layer both above and below the QD active region displaces misfit dislocations and substantially improves performance: we measure a twofold reduction in lasing threshold currents and a greater than threefold increase in output power. Our results suggest that devices employing both traditional threading dislocation reduction techniques and optimized misfit dislocation trapping layers may finally lead to fully integrated, commercially viable silicon-based photonic integrated circuits.Comment: 9 pages, 6 figure

Tackling Exascale Software Challenges in Molecular Dynamics Simulations with GROMACS

GROMACS is a widely used package for biomolecular simulation, and over the last two decades it has evolved from small-scale efficiency to advanced heterogeneous acceleration and multi-level parallelism targeting some of the largest supercomputers in the world. Here, we describe some of the ways we have been able to realize this through the use of parallelization on all levels, combined with a constant focus on absolute performance. Release 4.6 of GROMACS uses SIMD acceleration on a wide range of architectures, GPU offloading acceleration, and both OpenMP and MPI parallelism within and between nodes, respectively. The recent work on acceleration made it necessary to revisit the fundamental algorithms of molecular simulation, including the concept of neighborsearching, and we discuss the present and future challenges we see for exascale simulation - in particular a very fine-grained task parallelism. We also discuss the software management, code peer review and continuous integration testing required for a project of this complexity.Comment: EASC 2014 conference proceedin

An exploration of the experiences and utility of functional electrical stimulation for foot drop in people with multiple sclerosis

Purpose: Functional electrical stimulation (FES) is effective in improving walking in people with multiple sclerosis (MS) with foot drop. There is limited research exploring people’s experiences of using this device. This study aims to explore the utility, efficacy, acceptability, and impact on daily life of the device in people with MS. Methods: An interpretative phenomenological approach was employed. Ten participants who had used FES for 12 months were interviewed. Transcripts were analysed, and emergent themes identified. Results: Nine participants continued to use the device. Three relevant super-ordinate themes were identified; impact of functional electrical stimulation, sticking with functional electrical stimulation, and autonomy and control. Participants reported challenges using the device; however, all reported positive physical and psychological benefits. Intrinsic and external influences such as; access to professional help, the influence of others, an individual’s ability to adapt, and experiences using the device, influenced their decisions to continue with the device. A thematic model of these factors was developed. Conclusions: This study has contributed to our understanding of people with MS experiences of using the device and will help inform prescribing decisions and support the continued, appropriate use of FES over the longer term

Area and individual differences in personal crime victimization incidence: The role of individual, lifestyle/routine activities and contextual predictors

This article examines how personal crime differences between areas and between individuals are predicted by area and population heterogeneity and their synergies. It draws on lifestyle/routine activities and social disorganization theories to model the number of personal victimization incidents over individuals including routine activities and area characteristics, respectively, as well as their (cross-cluster) interactions. The methodology employs multilevel or hierarchical negative binomial regression with extra binomial variation using data from the British Crime Survey and the UK Census. Personal crime rates differ substantially across areas, reflecting to a large degree the clustering of individuals with measured vulnerability factors in the same areas. Most factors suggested by theory and previous research are conducive to frequent personal victimization except the following new results. Pensioners living alone in densely populated areas face disproportionally high numbers of personal crimes. Frequent club and pub visits are associated with more personal crimes only for males and adults living with young children, respectively. Ethnic minority individuals experience fewer personal crimes than whites. The findings suggest integrating social disorganization and lifestyle theories and prioritizing resources to the most vulnerable, rather than all, residents of poor and densely populated areas to prevent personal crimes

Types of problems elicited by verbal protocols for blind and sighted participants

Verbal protocols are often used in user-based studies of interactive technologies. This study investigated whether different types of problems are revealed by concurrent and retrospective verbal protocols (CVP and RVP) for blind and sighted participants. Eight blind and eight sighted participants undertook both CVP and RVP on four websites. Overall, interactivity problems were significantly more frequent in comparison to content or information architecture problems. In addition, RVP revealed significantly more interactivity problems than CVP for both user groups. Finally, blind participants encountered significantly more interactivity problems than sighted participants. The findings have implications for which protocol is appropriate, depending on the purpose of a particular study and the user groups involved

Strongly hyperpolarized gas from parahydrogen by rational design of ligand-capped nanoparticles

The production of hyperpolarized fluids in continuous mode would broaden substantially the range of applications in chemistry, materials science, and biomedicine. Here we show that the rational design of a heterogeneous catalyst based on a judicious choice of metal type, nanoparticle size and surface decoration with appropriate ligands leads to highly efficient pairwise addition of dihydrogen across an unsaturated bond. This is demonstrated in a parahydrogen-induced polarization (PHIP) experiment by a 508-fold enhancement (±78) of a CH3 proton signal and a corresponding 1219-fold enhancement (±187) of a CH2 proton signal using nuclear magnetic resonance (1H-NMR). In contrast, bulk metal catalyst does not show this effect due to randomization of reacting dihydrogen. Our approach results in the largest gas-phase NMR signal enhancement by PHIP known to date. Sensitivity-enhanced NMR with this technique could be used to image microfluidic reactions in-situ, to probe nonequilibrium thermodynamics or for the study of metabolic reactions

CD4+ T Cell Effects on CD8+ T Cell Location Defined Using Bioluminescence

T lymphocytes of the CD8+ class are critical in delivering cytotoxic function and in controlling viral and intracellular infections. These cells are “helped” by T lymphocytes of the CD4+ class, which facilitate their activation, clonal expansion, full differentiation and the persistence of memory. In this study we investigated the impact of CD4+ T cells on the location of CD8+ T cells, using antibody-mediated CD4+ T cell depletion and imaging the antigen-driven redistribution of bioluminescent CD8+ T cells in living mice. We documented that CD4+ T cells influence the biodistribution of CD8+ T cells, favoring their localization to abdominal lymph nodes. Flow cytometric analysis revealed that this was associated with an increase in the expression of specific integrins. The presence of CD4+ T cells at the time of initial CD8+ T cell activation also influences their biodistribution in the memory phase. Based on these results, we propose the model that one of the functions of CD4+ T cell “help” is to program the homing potential of CD8+ T cells