Effective dark matter halo catalog in f(R) gravity

We introduce the idea of an effective dark matter halo catalog in f(R) gravity, which is built using the effective density field. Using a suite of high resolution N-body simulations, we find that the dynamical properties of halos, such as the distribution of density, velocity dispersion, specific angular momentum and spin, in the effective catalog of f(R) gravity closely mimic those in the cold dark matter model with a cosmological constant (ΛCDM). Thus, when using effective halos, an f(R) model can be viewed as a ΛCDM model. This effective catalog therefore provides a convenient way for studying the baryonic physics, the galaxy halo occupation distribution and even semianalytical galaxy formation in f(R) cosmologies

Predation-driven biotic resistance fails to restrict the spread of a sessile rocky shore invader

The invasive barnacle Balanus glandula has progressively spread along the South African west coast. We used multiple approaches to assess the role of predation by indigenous whelks in regulating this expansion. B. glandula abundance and distribution were monitored annually while field observations and laboratory experiments assessed the relative predation pressure on B. glandula and the native barnacle Notomegabalanus algicola. In the mid-shore, the whelks Trochia cingulata and Burnt1pena lagenaria fed on N. algicola most often despite the alien B. glandula covering a mean of 86% of the shore at this site. Lower on the shore, the same feeding pattern was evident, although N. algicola was spatially dominant. Feeding experiments revealed that small (mean ± SD shell length: 13.9 ± 0.3 mm) and large (19.6 ± 0.5 mm) T. cingulata consumed up to 70% more N. algicola than B. glandula, displaying a significant avoidance of the alien. While small (15.5 ± 0.5 mm) B. lagenaria displayed the same pattern, large individuals (27.7 ± 0.4 mm) consumed equal numbers of the 2 barnacles. The avoidance of B. glandula may be explained by this species possessing thicker shell and opercular plates than N. algicola, while a narrow margin of vulnerable soft tissue around the circumference of the opercular plates makes the native an attractive prey choice. This study demonstrates that predation-driven biotic resistance has not contained the expansion of B. glandula along the South African coast

Scenario-Based Thinking to Negotiate Coastal Squeeze of Ecosystems: Green, blue, grey, and hybrid infrastructures for climate adaptation and resilience

Scott Hawken, Kaihang Zhou, Luke Mosley and Emily Leyde

Gravitational Flexion by Elliptical Dark Matter Haloes

We present equations for the gravitational lensing flexion expected for an elliptical lens mass distribution. These can be reduced to one-dimensional finite integrals, thus saving significant computing time over a full two-dimensional calculation. We estimate constraints on galaxy halo ellipticities for a range of potential future surveys, finding that the constraints from the two different types of flexion are comparable and are up to two orders of magnitude tighter than those from shear. Flexion therefore appears to be a very promising potential tool for constraining the shapes of galaxy haloes from future surveys.Comment: 7 pages, 5 figures, submitted to MNRA

Measuring the growth rate of structure around cosmic voids

Using an algorithm based on searching for empty spheres we identified 245 voids in the VIMOS Public Extragalactic Redshift Survey (VIPERS). We show how by modelling the anisotropic void-galaxy cross correlation function we can probe the growth rate of structure

Experiences of autism spectrum disorder and policing in England and Wales:surveying police and the autism community

An online survey gathered the experiences and views of 394 police officers (from England and Wales) regarding autism spectrum disorder (ASD). Just 42 % of officers were satisfied with how they had worked with individuals with ASD and reasons for this varied. Although officers acknowledged the need for adjustments, organisational/time constraints were cited as barriers. Whilst 37 % of officers had received training on ASD, a need for training tailored to policing roles (e.g., frontline officers, detectives) was identified. Police responses are discussed with respect to the experiences of the ASD community (31 adults with ASD, 49 parents), who were largely dissatisfied with their experience of the police and echoed the need for police training on ASD

MetaCAM: Ensemble-Based Class Activation Map

The need for clear, trustworthy explanations of deep learning model predictions is essential for high-criticality fields, such as medicine and biometric identification. Class Activation Maps (CAMs) are an increasingly popular category of visual explanation methods for Convolutional Neural Networks (CNNs). However, the performance of individual CAMs depends largely on experimental parameters such as the selected image, target class, and model. Here, we propose MetaCAM, an ensemble-based method for combining multiple existing CAM methods based on the consensus of the top-k% most highly activated pixels across component CAMs. We perform experiments to quantifiably determine the optimal combination of 11 CAMs for a given MetaCAM experiment. A new method denoted Cumulative Residual Effect (CRE) is proposed to summarize large-scale ensemble-based experiments. We also present adaptive thresholding and demonstrate how it can be applied to individual CAMs to improve their performance, measured using pixel perturbation method Remove and Debias (ROAD). Lastly, we show that MetaCAM outperforms existing CAMs and refines the most salient regions of images used for model predictions. In a specific example, MetaCAM improved ROAD performance to 0.393 compared to 11 individual CAMs with ranges from -0.101-0.172, demonstrating the importance of combining CAMs through an ensembling method and adaptive thresholding.Comment: 9 page

Synthesis and Structural Investigation of an \u27Oxazinoquinolinespirohexadienone\u27 That Only Exists as Its Long-Wavelength Ring-Opened Quinonimine Isomer

The spirocyclic oxazinoquinolinespirohexadienone (OSHD) photochromes are computationally predicted to be an attractive target as electron deficient analogues of the perimidinespirohexadienone (PSHD) photochromes, for eventual application as photochromic photooxidants. We have found the literature method for their preparation unsuitable and present an alternative synthesis. Unfortunately the product of this synthesis is the long wavelength (LW) ring-opened quinonimine isomer of the OSHD. We have found this isomer does not close to the spirocyclic short wavelength isomer (SW) upon prolonged standing in the dark, unlike other PSHD photochromes. The structure of this long wavelength isomer was found by NMR and X-ray crystallography to be exclusively the quinolinone (keto) tautomer, though experimental cyclic voltammetry supported by our computational methodology indicates that the quinolinol (enol) tautomer (not detected by other means) may be accessible through a fast equilibrium lying far toward the keto tautomer. Computations also support the relative stability order of keto LW over enol LW over SW

The VIMOS Public Extragalactic Redshift Survey - Searching for Cosmic Voids

The characterisation of cosmic voids gives unique information about the large-scale distribution of galaxies, their evolution and the cosmological model. We identify and characterise cosmic voids in the VIMOS Public Extragalactic Redshift Survey (VIPERS) at redshift 0.55 < z < 0.9. A new void search method is developed based upon the identification of empty spheres that fit between galaxies. The method can be used to characterise the cosmic voids despite the presence of complex survey boundaries and internal gaps. We investigate the impact of systematic observational effects and validate the method against mock catalogues. We measure the void size distribution and the void-galaxy correlation function. We construct a catalogue of voids in VIPERS. The distribution of voids is found to agree well with the distribution of voids found in mock catalogues. The void-galaxy correlation function shows indications of outflow velocity from the voids