A colimit decomposition for homotopy algebras in Cat

Badzioch showed that in the category of simplicial sets each homotopy algebra of a Lawvere theory is weakly equivalent to a strict algebra. In seeking to extend this result to other contexts Rosicky observed a key point to be that each homotopy colimit in simplicial sets admits a decomposition into a homotopy sifted colimit of finite coproducts, and asked the author whether a similar decomposition holds in the 2-category of categories Cat. Our purpose in the present paper is to show that this is the case.Comment: Some notation changed; small amount of exposition added in intr

Molecular Emission in Active Centres of Nearby Galaxies

The work of this thesis focuses on observations of molecular rotational lines, which are used to uncover the properties of some of the most extreme regions of nearby galaxies. We complete this by both direct analysis of the observations, and using a suite of astrochemical models. We study the distribution of CS in two nearby starburst galaxies, NGC 6946 and NGC 3079. Two low-J lines of CS are observed with the IRAM-30m telescope in a region spanning 50′′ about the centre of each galaxy. Both lines have a high critical density that makes CS a good tracer of dense, star-forming gas. Through LTE analysis and a coupled radiative transfer-chemical modelling, we find a temperature and density gradient from the centre of NGC 6946 to the offset pointings. In NGC 3079, we find uniform temperature. We also present observations of SiO and HNCO in nearby galaxy NGC 1068 from the Plateau de Bure interferometer (PdBI). We see four clear peaks, one for each molecule to both the west and the east of the AGN. From a detailed chemical modelling we find that a high SiO abundance and low HNCO indicate a fast shock, while high HNCO and low SiO indicates either a slow shock or warm, dense, non-shocked gas. Comparing to observations, the east is therefore likely to contain gas that is heavily shocked. Gas to the west may be non-shocked, or maybe undergoing a much milder shock event. We complete a radiative transfer modelling. Taking into account these results, the milder shock event is the more likely of the two. Finally, ALMA observations of the distribution of several molecules in NGC 1068 are analysed. These molecules trace different components of the molecular gas in the AGN, circumnuclear disc and starburst ring. Spectral analysis of each molecule, and the ratio between molecules are used to determine galaxy properties and how these vary from region to region

Categorified quantum sl(2) is an inverse limit of flag 2-categories

We prove that categorified quantum sl(2) is an inverse limit of Flag 2-categories defined using cohomology rings of iterated flag varieties. This inverse limit is an instance of a 2-limit in a bicategory giving rise to a universal property that characterizes the categorification of quantum sl(2) uniquely up to equivalence. As an application we characterize all bimodule homomorphisms in the Flag 2-category and prove that the categorified quantum Casimir of sl(2) acts appropriately on these 2-representations.Comment: 21 pages, with xypic diagrams. v2 corrects typo

Reversal of Pathogen-Induced Barrier Defects in Intestinal Epithelial Cells by Contra-pathogenicity Agents.

“This is a post-peer-review, pre-copyedit version of a protocol published in Digestive Diseases and Sciences The final publication is available at https://doi.org/10.1007/s10620-020-06121-9"BACKGROUND: Environmental enteropathy (EE) is associated with stunting, impairment of responses to oral vaccines, and other adverse health consequences in young children throughout the developing world. EE is characterized by chronic low-grade intestinal inflammation and disrupted epithelial barrier integrity, partly resulting from dysregulation of tight junction proteins, observed in other enteropathies such as celiac disease. During EE, this dysregulation of tight junction expression amplifies translocation of pathogenic bacteria across the intestinal mucosa. AIMS: The aim was to determine whether enteropathogen-mediated epithelial barrier failure can be ameliorated using contra-pathogenicity therapies. METHODS: Intestinal epithelial barrier damage was assessed in Caco-2 cells incubated with three important enteropathogens identified in EE patients: Enteropathogenic Escherichia coli (EPEC), Citrobacter rodentium (C. rodentium), and Cryptosporidium parvum (C. parvum). Potential therapeutic molecules were tested to detect effects on transepithelial resistance (TER), bacterial translocation (BT), claudin-4 expression, and regulation of the inflammatory cytokine response. RESULTS: All three enteropathogens compared to uninfected cells, reduced TER (EPEC; p < 0.0001, C. rodentium; p < 0.0001, C. parvum; p < 0.0007), reduced claudin-4 expression, and permitted BT (EPEC; p < 0.0001, C. rodentium; p < 0.0001, C. parvum; p < 0.0003) through the monolayer. Zinc, colostrum, epidermal growth factor, trefoil factor 3, resistin-like molecule-β, hydrocortisone, and the myosin light chain kinase inhibitor ML7 (Hexahydro-1-[(5-iodo-1-naphthalenyl)sulfonyl]-1H-1,4-diazepine hydrochloride); ML7) improved TER (up to 70%) and decreased BT (as much as 96%). Only zinc demonstrated modest antimicrobial activity. CONCLUSION: The enteropathogens impaired intestinal-epithelial barrier integrity with dysregulation of claudin-4 and increased bacterial translocation. Enteropathogen-mediated damage was reduced using contra-pathogenicity agents which mitigated the effects of pathogens without direct antimicrobial activity

Temporal blocking of finite-difference stencil operators with sparse "off-the-grid" sources

Stencil kernels dominate a range of scientific applications, including seismic and medical imaging, image processing, and neural networks. Temporal blocking is a performance optimization that aims to reduce the required memory bandwidth of stencil computations by re-using data from the cache for multiple time steps. It has already been shown to be beneficial for this class of algorithms. However, applying temporal blocking to practical applications' stencils remains challenging. These computations often consist of sparsely located operators not aligned with the computational grid (“off-the-grid”). Our work is motivated by modelling problems in which source injections result in wavefields that must then be measured at receivers by interpolation from the grided wavefield. The resulting data dependencies make the adoption of temporal blocking much more challenging. We propose a methodology to inspect these data dependencies and reorder the computation, leading to performance gains in stencil codes where temporal blocking has not been applicable. We implement this novel scheme in the Devito domain-specific compiler toolchain. Devito implements a domain-specific language embedded in Python to generate optimized partial differential equation solvers using the finite-difference method from high-level symbolic problem definitions. We evaluate our scheme using isotropic acoustic, anisotropic acoustic, and isotropic elastic wave propagators of industrial significance. After auto-tuning, performance evaluation shows that this enables substantial performance improvement through temporal blocking over highly-optimized vectorized spatially-blocked code of up to 1.6x

Induction of CYP2E1 activity in liver transplant patients as measured by chlorzoxazone 6-hydroxylation

Objective: To examine the phenotypic expression of CYP2E1 in liver transplant patients, as measured by the in vivo probe chlorzoxazone, and to evaluate CYP2E1 activity over me after transplantation. Methods: Thirty-three stable liver transplant: patients were given 250 mg chlorzoxazone within 1 year after transplantation as part of a multiprobe CYP cocktail; urine and blood were collected for 8 hours. Chlorzoxazone and 6-hydroxychlorzoxazone concentrations were determined by HPLC. Twenty-eight healthy control subjects, eight patients with moderate to severe liver disease, and four patients who had not received liver transplants were also studied for comparison. The chlorzoxazone metabolic ratio, calculated as the plasma concentration of 6-hydroxychlorzoxazone/chlorzoxazone at 4 hours after chlorzoxazone administration, was used as the phenotypic, index. In a subgroup of patients and control subjects, additional blood samples were obtained to allow for the calculation of chlorzoxazone pharmacokinetic parameters by noncompartmental methods. Results: The chlorzoxazone metabolic ratio for the liver transplant patients in the first month after transplantation (mean ± SD, 6.4 ± 5.1) was significantlp higher than that after 1 month after surgery (2.1 ± 2.0), when the chlorzoxazone metabolic ratio was not different from control subjects (0.8 ± 0.5). The chlorzoxazone metabolic ratios in the patients who had not received liver transplants (1.1 ± 0.7) were equivalent to those of healthy control subjects. The maximum observed 6-hydroxychlorzoxazone plasma concentration was 3046 ± 1848 ng/ml in seven liver transplant patients in the first month after surgery compared with 1618 ± 320 ng/ml in 16 healthy control subjects (p < 0.05). The maximum observed concentration of chlorzoxazone, the chlorzoxazone apparent oral clearance, and the formation clearance of 6-hydroxychlorzoxazone were also significantly different between the groups. Conclusions: We conclude that significant induction of CYP2E1, as indicated by the chlorzoxazone metabolic, ratio, occurs in the first month after surgery in liver transplant patients and that drugs that are substrates for CYP2E1 may require dosage alteration during that period. Contrary to expectations, drug metabolism is not uniformly depressed after liver transplantation

Do TETRA (Airwave) base station signals have a short-term impact on health and well-being? A randomized double-blind provocation study

Background: "Airwave" is the new communication system currently being rolled out across the United Kingdom for the police and emergency services, based on the Terrestrial Trunked Radio Telecommunications System (TETRA). Some police officers have complained about skin rashes, nausea, headaches, and depression as a consequence of using their Airwave handsets. In addition, a small subgroup in the population self-report being sensitive to electromagnetic fields (EMFs) in general. Objectives: We conducted a randomized double-blind provocation study to establish whether short-term exposure to a TETRA base station signal has an impact on the health and well-being of individuals with self-reported "electrosensitivity" and of participants who served as controls.Methods: Fifty-one individuals with self-reported electrosensitivity and 132 age and sex-matched controls participated in an open provocation test; 48 sensitive and 132 control participants went on to complete double-blind tests in a fully screened semianechoic chamber. Heart rate, skin conductance, and blood pressure readings provided objective indices of short-term physiological response. Visual analog scales and symptom scales provided subjective indices of well-being.Results: We found no differences on any measure between TETRA and sham (no signal) under double-blind conditions for either controls or electrosensitive participants, and neither group could detect the presence of a TETRA signal at rates greater than chance (50%). When conditions were not double blind, however, the self-reported electrosensitive individuals did report feeling worse and experienced more severe symptoms during TETRA compared with sham.Conclusions: Our findings suggest that the adverse symptoms experienced by electrosensitive individuals are due to the belief of harm from TETRA base stations rather than to the low-level EMF exposure itself

Systematic review and meta-analysis of effects of community-delivered positive youth development interventions on violence outcomes

Background We systematically reviewed and meta-analysed evaluations testing the effectiveness of positive youth development (PYD) interventions for reducing violence in young people. Methods Two reviewers working independently screened records, assessed full-text studies for inclusion and extracted data. Outcomes were transformed to Cohen's d. Quality assessment of included evaluations was undertaken using the Cochrane risk of bias tool. Effect sizes were combined using multilevel meta-analysis. We searched 21 databases, including MEDLINE, PsycINFO, CINAHL and CENTRAL, and hand-searched key journals and websites. We included studies where the majority of participants were aged 11–18 years and where interventions were delivered in community (not clinical or judicial) settings outside of normal school hours. We excluded studies targeting predefined physical and mental health conditions or parents/carers alongside young people. We defined violence as perpetration or victimisation of physical violence including violent crime. Results Three randomised trials were included in this systematic review. Included evaluations each had design flaws. Meta-analyses suggested that PYD interventions did not have a statistically significant effect on violence outcomes across all time points (d=0.021, 95% CI −0.050 to 0.093), though interventions did have a statistically significant short-term effect (d=0.076, 95% CI 0.013 to 0.140). Conclusions Our meta-analyses do not offer evidence of PYD interventions in general having effects of public health significance in reducing violence among young people. Evaluations did not consistently report theories of change or implementation fidelity, so it is unclear if our meta-analyses provide evidence that the PYD theory of change is ineffective in reducing violence among young people

Architecture and performance of Devito, a system for automated stencil computation

Stencil computations are a key part of many high-performance computing applications, such as image processing, convolutional neural networks, and finite-difference solvers for partial differential equations. Devito is a framework capable of generating highly-optimized code given symbolic equations expressed in Python, specialized in, but not limited to, affine (stencil) codes. The lowering process -- from mathematical equations down to C++ code -- is performed by the Devito compiler through a series of intermediate representations. Several performance optimizations are introduced, including advanced common sub-expressions elimination, tiling and parallelization. Some of these are obtained through well-established stencil optimizers, integrated in the back-end of the Devito compiler. The architecture of the Devito compiler, as well as the performance optimizations that are applied when generating code, are presented. The effectiveness of such performance optimizations is demonstrated using operators drawn from seismic imaging applications

Negotiation in strategy making teams : group support systems and the process of cognitive change

This paper reports on the use of a Group Support System (GSS) to explore at a micro level some of the processes manifested when a group is negotiating strategy-processes of social and psychological negotiation. It is based on data from a series of interventions with senior management teams of three operating companies comprising a multi-national organization, and with a joint meeting subsequently involving all of the previous participants. The meetings were concerned with negotiating a new strategy for the global organization. The research involved the analysis of detailed time series data logs that exist as a result of using a GSS that is a reflection of cognitive theory