Isotropy, shear, symmetry and exact solutions for relativistic fluid spheres

The symmetry method is used to derive solutions of Einstein's equations for fluid spheres using an isotropic metric and a velocity four vector that is non-comoving. Initially the Lie, classical approach is used to review and provide a connecting framework for many comoving and so shear free solutions. This provides the basis for the derivation of the classical point symmetries for the more general and mathematicaly less tractable description of Einstein's equations in the non-comoving frame. Although the range of symmetries is restrictive, existing and new symmetry solutions with non-zero shear are derived. The range is then extended using the non-classical direct symmetry approach of Clarkson and Kruskal and so additional new solutions with non-zero shear are also presented. The kinematics and pressure, energy density, mass function of these solutions are determined.Comment: To appear in Classical and Quantum Gravit

Uncertainty modeling and interpretability in convolutional neural networks for polyp segmentation

Convolutional Neural Networks (CNNs) are propelling advances in a range of different computer vision tasks such as object detection and object segmentation. Their success has motivated research in applications of such models for medical image analysis. If CNN-based models are to be helpful in a medical context, they need to be precise, interpretable, and uncertainty in predictions must be well understood. In this paper, we develop and evaluate recent advances in uncertainty estimation and model interpretability in the context of semantic segmentation of polyps from colonoscopy images. We evaluate and enhance several architectures of Fully Convolutional Networks (FCNs) for semantic segmentation of colorectal polyps and provide a comparison between these models. Our highest performing model achieves a 76.06% mean IOU accuracy on the EndoScene dataset, a considerable improvement over the previous state-of-the-art

Genetic Diversity in Commercially Exploited Fish Species

This document was produced during a three-day seminar and workshop on the genetic diversity of commercially exploited fish species in Nordic waters held at Holar College, Iceland. The aim of the seminar was to discuss current knowledge regarding the effects of commercial fishing activities on the genetic diversity of wild, marine species of fish in Nordic waters, and to provide recommendations for necessary actions to minimize further loss of such diversity. This document expresses the joint view of the selected expert scientists invited to the meeting, and the content concerns fish populations exploited in Nordic waters. During the first day of the meeting short presentations were given by some of the participants. The abstracts of these presentations are provided in Appendix 2 and the full workshop program in Appendix 3. Topics for working groups during workshop sections, and the initial questions outlined for the discussions are provided in Appendix 4

Mycotoxin exposure and human cancer risk : a systematic review of epidemiological studies

In recent years, there has been an increasing interest in investigating the carcinogenicity of mycotoxins in humans. This systematic review aims to provide an overview of data linking exposure to different mycotoxins with human cancer risk. Publications (2019 and earlier) of case–control or longitudinal cohort studies were identified in PubMed and EMBASE. These articles were then screened by independent reviewers and their quality was assessed according to the Newcastle–Ottawa scale. Animal, cross‐sectional, and molecular studies satisfied criteria for exclusion. In total, 14 articles were included: 13 case–control studies and 1 longitudinal cohort study. Included articles focused on associations of mycotoxin exposure with primary liver, breast, and cervical cancer. Overall, a positive association between the consumption of aflatoxin‐contaminated foods and primary liver cancer risk was verified. Two case–control studies in Africa investigated the relationship between zearalenone and its metabolites and breast cancer risk, though conflicting results were reported. Two case–control studies investigated the association between hepatocellular carcinoma and fumonisin B1 exposure, but no significant associations were observed. This systematic review incorporates several clear observations of dose‐dependent associations between aflatoxins and liver cancer risk, in keeping with IARC Monograph conclusions. Only few human epidemiological studies investigated the associations between mycotoxin exposures and cancer risk. To close this gap, more in‐depth research is needed to unravel evidence for other common mycotoxins, such as deoxynivalenol and ochratoxin A. The link between mycotoxin exposures and cancer risk has mainly been established in experimental studies, and needs to be confirmed in human epidemiological studies to support the evidence‐based public health strategies

Invariant construction of solutions to Einstein's field equations - LRS perfect fluids II

The properties of LRS class II perfect fluid space-times are analyzed using the description of geometries in terms of the Riemann tensor and a finite number of its covariant derivatives. In this manner it is straightforward to obtain the plane and hyperbolic analogues to the spherical symmetric case. For spherically symmetric static models the set of equations is reduced to the Tolman-Oppenheimer-Volkoff equation only. Some new non-stationary and inhomogeneous solutions with shear, expansion, and acceleration of the fluid are presented. Among these are a class of temporally self-similar solutions with equation of state given by $p=(\gamma-1)\mu, 1<\gamma<2$, and a class of solutions characterized by $\sigma=-\Theta/6$. We give an example of geometry where the Riemann tensor and the Ricci rotation coefficients are not sufficient to give a complete description of the geometry. Using an extension of the method, we find the full metric in terms of curvature quantities.Comment: 24 pages, 1 figur

Learning the \u27How\u27 of the Law: Teaching Procedure and Legal Education

This article examines the approaches to teaching civil procedure in five common law jurisdictions (Canada, Australia, United States, Israel, and England). The paper demonstrates the important transition of civil procedure from a vocational oriented subject to a rigorous intellectual study of policies, processes, and values underpinning our civil justice system, and analysis of how that system operates. The advantages and disadvantages of where civil procedure fits within the curriculum are discussed and the significant opportunities for ‘active’ learning are highlighted. The inclusion of England where civil procedure is not taught to any significant degree in the law degree provides a valuable comparator. Common findings from the other jurisdictions suggest that teaching civil procedure enhances the curriculum by bringing it closer to what lawyers actually do as well as enabling a better understanding of the development of doctrinal law

Learning the \u27How\u27 of the Law: Teaching Procedure and Legal Education

This article examines the approaches to teaching civil procedure in five common law jurisdictions (Canada, Australia, United States, Israel, and England). The paper demonstrates the important transition of civil procedure from a vocational oriented subject to a rigorous intellectual study of policies, processes, and values underpinning our civil justice system, and analysis of how that system operates. The advantages and disadvantages of where civil procedure fits within the curriculum are discussed and the significant opportunities for ‘active’ learning are highlighted. The inclusion of England where civil procedure is not taught to any significant degree in the law degree provides a valuable comparator. Common findings from the other jurisdictions suggest that teaching civil procedure enhances the curriculum by bringing it closer to what lawyers actually do as well as enabling a better understanding of the development of doctrinal law

Genotype reconstruction of paternity in European lobsters (Homarus gammarus)

This is the author accepted manuscript. The final version is available on open access from Public Library of Science via the DOI in this recordData Availability: Microsatellite genotypes of 312 individuals (13 spatial samples of 24 individuals), used in the calculation of regional allele frequencies, microsatellite characterisation, and tests of HWE, linkage and null alleles, are available on the Dryad Digital Repository at http://dx.doi.org/10.5061/dryad.v176mDecapod crustaceans exhibit considerable variation in fertilisation strategies, ranging from pervasive single paternity to the near-ubiquitous presence of multiple paternity, and such knowledge of mating systems and behaviour are required for the informed management of commercially-exploited marine fisheries. We used genetic markers to assess the paternity of individual broods in the European lobster, Homarus gammarus, a species for which paternity structure is unknown. Using 13 multiplexed microsatellite loci, three of which are newly described in this study, we genotyped 10 eggs from each of 34 females collected from an Atlantic peninsula in the south-western United Kingdom. Single reconstructed paternal genotypes explained all observed progeny genotypes in each of the 34 egg clutches, and each clutch was fertilised by a different male. Simulations indicated that the probability of detecting multiple paternity was in excess of 95% if secondary sires account for at least a quarter of the brood, and in excess of 99% where additional sire success was approximately equal. Our results show that multiple paternal fertilisations are either absent, unusual, or highly skewed in favour of a single male among H. gammarus in this area. Potential mechanisms upholding single paternal fertilisation are discussed, along with the prospective utility of parentage assignments in evaluations of hatchery stocking and other fishery conservation approaches in light of this finding.European Social FundFisheries Charitable Trust of the Fishmongers' Company, U

A few questions about curves on surfaces

In this note we address the following kind of question: let X be a smooth, irreducible, projective surface and D a divisor on X satisfying some sort of positivity hypothesis, then is there some multiple of D depending only on X which is effective or movable? We describe some examples, discuss some conjectures and prove some results that suggest that the answer should in general be negative, unless one puts some really strong hypotheses either on D or on X