Large Fluctuations in the High-Redshift Metagalactic Ionizing Background

Recent observations have shown that the scatter in opacities among coeval segments of the Lyman-alpha forest increases rapidly at z > 5. In this paper, we assess whether the large scatter can be explained by fluctuations in the ionizing background in the post-reionization intergalactic medium. We find that matching the observed scatter at z ~ 5.5 requires a short spatially averaged mean free path of 3 shorter than direct measurements at z ~ 5.2. We argue that such rapid evolution in the mean free path is difficult to reconcile with our measurements of the global H I photoionization rate, which stay approximately constant over the interval z ~ 4.8 - 5.5. However, we also show that measurements of the mean free path at z > 5 are likely biased towards higher values by the quasar proximity effect. This bias can reconcile the short values of the mean free path that are required to explain the large scatter in opacities. We discuss the implications of this scenario for cosmological reionization. Finally, we investigate whether other statistics applied to the z > 5 Lyman-alpha forest can shed light on the origin of the scatter. Compared to a model with a uniform ionizing background, models that successfully account for the scatter lead to enhanced power in the line-of-sight flux power spectrum on scales k < 0.1 h/Mpc. We find tentative evidence for this enhancement in observations of the high-redshift Lyman-alpha forest.Comment: Matches version published by MNRAS with clarifications and expanded discussio

Selfish Dark Matter

We present a mechanism where a particle asymmetry in one sector is used to generate an asymmetry in another sector. The two sectors are not coupled through particle number violating interactions and are not required to be in thermal contact with each other. When this mechanism is applied to baryogenesis in asymmetric dark matter models, we find that the dark matter particles can be extremely light, e.g. much lighter than an eV, and that in some cases there is no need to annihilate away the symmetric component of dark matter. We discuss a concrete realization of the mechanism with signals in direct detection, at the LHC, at $B$-factories or future beam dump experiments.Comment: 18+5 pages, 2 figures; Journal version: Added references, small changes to the free-streaming length estimate

Mary Watts and Elena Polenova: Kindred Spirits of the Arts and Crafts Movement

This article studies two important women of the Arts and Crafts Movement during the late nineteenth century, the Scottish artist Mary Watts and the Russian artist Elena Polenova, and considers similarities in their lives and works which have never before been observed. Though starting their careers in remote locations and cultures, their personal philosophies and conse-quent artistic choices brought about a striking convergence in their lives, culminating in the mu-tuality, not just of creative output, but also of direct personal links and acquaintances. Starting with a broad consideration of the Arts and Crafts Movement, the paper locates the women within their respective national movements and notes shared elements within Brit-ish and Russian Arts and Crafts ideologies. The article then addresses the role played in the women’s thinking by the distinguished artistic networks into which they were linked. By exten-sion, the study then considers the channels and degree of contact, influence and artistic ex-change between different national groups and the extent to which the women can be said to have participated in a broad international movement. The paper reveals just how close the two women came to personal acquaintance. The tragic early death of Elena Polenova, the rise of the Russian avant-garde, and the Soviet art historical bias against her artistic movement, on the one hand, and Mary Watts’s widowhood, subsequent career divergence, and the rise of British modernism on the other, combined to foreshorten their artistic careers and obscure their legacy for much of the twentieth century. Research for this project has brought about discussions be-tween the English and Russian curators of Mary Watts and Elena Polenova’s legacies towards a range of future collaborative enterprises

Cryptosporidium cuniculus - new records in human and kangaroo in Australia

BACKGROUND: To date, Cryptosporidium cuniculus has been found exclusively in rabbits and humans. The present study provides the first published molecular evidence for C. cuniculus in an Australian human patient as well as a kangaroo. FINDINGS: Using PCR-based sequencing of regions in the actin, 60 kDa glycoprotein (gp60) and small subunit of ribosomal RNA (SSU) genes, we identified a new and unique C. cuniculus genotype (akin to VbA25) from a human, and C. cuniculus genotype VbA26 from an Eastern grey kangaroo (Macropus giganteus) in Australia. CONCLUSIONS: The characterisation of these genotypes raises questions as to their potential to infect humans and/or other animals in Australia, given that C. cuniculus has been reported to cause cryptosporidiosis outbreaks in Europe

Cryptosporidium and Giardia taxa in faecal samples from animals in catchments supplying the city of Melbourne with drinking water (2011 to 2015)

BACKGROUND: In a long-term program to monitor pathogens in water catchments serving the City of Melbourne in the State of Victoria in Australia, we detected and genetically characterised Cryptosporidium and Giardia in faecal samples from various animals in nine water reservoir areas over a period of 4 years (July 2011 to November 2015). METHODS: This work was conducted using PCR-based single-strand conformation polymorphism (SSCP) and phylogenetic analyses of portions of the small subunit of ribosomal RNA (SSU) and 60 kDa glycoprotein (gp60) genes for Cryptosporidium, and triose-phosphate isomerase (tpi) gene for Giardia. RESULTS: The prevalence of Cryptosporidium was 1.62 % (69 of 4,256 samples); 25 distinct sequence types were defined for pSSU, and six for gp60 which represented C. hominis (genotype Ib - subgenotype IbA10G2), C. cuniculus (genotype Vb - subgenotypes VbA26, and VbA25), and C. canis, C. fayeri, C. macropodum, C. parvum, C. ryanae, Cryptosporidium sp. "duck" genotype, C. suis and C. ubiquitum as well as 12 novel SSU sequence types. The prevalence of Giardia was 0.31 % (13 of 4,256 samples); all three distinct tpi sequence types defined represented assemblage A of G. duodenalis. CONCLUSIONS: Of the 34 sequence types (genotypes) characterized here, five and one have been recorded previously for Cryptosporidium and Giardia, respectively, from humans. Novel genotypes of Cryptosporidium and Giardia were recorded for SSU (n = 12), gp60 (n = 4) and tpi (n = 1); the zoonotic potential of these novel genotypes is presently unknown. Future work will continue to monitor the prevalence of Cryptosporidium and Giardia genotypes in animals in these catchments, and expand investigations to humans. Nucleotide sequences reported in this paper are available in the GenBank database under accession nos. KU531647-KU531718

Inferring Mobility of Care Travel Behavior From Transit Origin-Destination Data

There are substantial differences in travel behavior by gender on public transit. Studies have concluded that these differences are largely attributable to household responsibilities typically falling disproportionately on women, leading to women being more likely to utilize transit for purposes referred to by the umbrella concept of "mobility of care". In contrast to past studies that have quantified the impact of gender using survey and qualitative data, we propose a novel data-driven workflow utilizing a combination of previously developed origin, destination, and transfer inference (ODX) based on individual transit fare card transactions, name-based gender inference, and geospatial analysis as a framework to identify mobility of care trip making. We apply this framework to data from the Washington Metropolitan Area Transit Authority (WMATA). Analyzing data from millions of journeys conducted in the first quarter of 2019, the results of this study show that our proposed workflow can identify mobility of care travel behavior, detecting times and places of interest where the share of women travelers in an equally-sampled subset (on basis of inferred gender) of transit users is 10% - 15% higher than that of men. The workflow presented in this study provides a blueprint for combining transit origin-destination data, inferred customer demographics, and geospatial analyses enabling public transit agencies to assess, at the fare card level, the gendered impacts of different policy and operational decisions.Comment: Updated reference formatting and discussion point