The First Large Absorption Survey in H i (FLASH) is a large-area radio survey for neutral hydrogen in and around galaxies in the intermediate redshift range 0.4 < z < 1.0, using the 21-cm H i absorption line as a probe of cold neutral gas. The survey uses the ASKAP radio telescope and will cover 24,000 deg2 of sky over the next five years. FLASH breaks new ground in two ways – it is the first large H i absorption survey to be carried out without any optical preselection of targets, and we use an automated Bayesian line-finding tool to search through large datasets and assign a statistical significance to potential line detections. Two Pilot Surveys, covering around 3000 deg2 of sky, were carried out in 2019-22 to test and verify the strategy for the full FLASH survey. The processed data products from these Pilot Surveys (spectral-line cubes, continuum images, and catalogues) are public and available online. In this paper, we describe the FLASH spectral-line and continuum data products and discuss the quality of the H i spectra and the completeness of our automated line search. Finally, we present a set of 30 new H i absorption lines that were robustly detected in the Pilot Surveys, almost doubling the number of known H i absorption systems at 0.4 < z < 1. The detected lines span a wide range in H i optical depth, including three lines with a peak optical depth τ > 1, and appear to be a mixture of intervening and associated systems. Interestingly, around two-thirds of the lines found in this untargeted sample are detected against sources with a peaked-spectrum radio continuum, which are only a minor (5-20%) fraction of the overall radio-source population. The detection rate for H i absorption lines in the Pilot Surveys (0.3 to 0.5 lines per 40 deg2 ASKAP field) is a factor of two below the expected value. One possible reason for this is the presence of a range of spectral-line artefacts in the Pilot Survey data that have now been mitigated and are not expected to recur in the full FLASH survey. A future paper in this series will discuss the host galaxies of the H i absorption systems identified here.

We develop a theory of generalized characters of local systems in $\infty $-categories, which extends classical character theory for group representations and, in particular, the induced character formula. A key aspect of our approach is that we utilize the interaction between traces and their categorifications. We apply this theory to reprove and refine various results on the composability of Becker-Gottlieb transfers, the Hochschild homology of Thom spectra, and the additivity of traces in stable $\infty $-categories.

We introduce the notion of echeloned spaces – an order-theoretic abstraction of metric spaces. The first step is to characterize metrizable echeloned spaces. It turns out that morphisms between metrizable echeloned spaces are uniformly continuous or have a uniformly discrete image. In particular, every automorphism of a metrizable echeloned space is uniformly continuous, and for every metric space with midpoints, the automorphisms of the induced echeloned space are precisely the dilations.

Next, we focus on finite echeloned spaces. They form a Fraïssé class, and we describe its Fraïssé-limit both as the echeloned space induced by a certain homogeneous metric space and as the result of a random construction. Building on this, we show that the class of finite ordered echeloned spaces is Ramsey. The proof of this result combines a combinatorial argument by Nešetřil and Hubička with a topological-dynamical point of view due to Kechris, Pestov and Todorčević. Finally, using the method of Katětov functors due to Kubiś and Mašulović, we prove that the full symmetric group on a countable set topologically embeds into the automorphism group of the countable universal homogeneous echeloned space.

In contradistinction to totalitarianism, Claude Lefort theorised a democratic form of society as one primarily characterised by indeterminacy, absence of ground, and by extension openness to the event. In maintaining this form of society, Lefort reserved a key role for human rights. The aims of this paper are twofold: first, I argue that, despite the fact that Lefort never developed a theory of constitutions, an important role can nonetheless be ascribed to them. I hypothesise constitutions to be key in democratic society’s symbolic representation of itself to itself. Second, I then examine what the repercussions are for this idea when Martin Loughlin’s account of constitutionalism is taken into account. Loughlin’s argument suggests that, while constitutions may have been important safeguards against totalitarianism, constitutions today threaten to become total themselves. I conclude by indicating the populist response as a point of convergence between Lefort’s and Loughlin’s analyses.

Let $F:\; {\mathscr {C}} \to {\mathscr {E}} \ $ be a functor from a category $\mathscr {C} \ $ to a homological (Borceux–Bourn) or semi-abelian (Janelidze–Márki–Tholen) category $\mathscr {E}$. We investigate conditions under which the homology of an object $X$ in $\mathscr {C}$ with coefficients in the functor $F$, defined via projective resolutions in $\mathscr {C}$, remains independent of the chosen resolution. Consequently, the left derived functors of $F$ can be constructed analogously to the classical abelian case.

Our approach extends the concept of chain homotopy to a non-additive setting using the technique of imaginary morphisms. Specifically, we utilize the approximate subtractions of Bourn–Janelidze, originally introduced in the context of subtractive categories. This method is applicable when $\mathscr {C}$ is a pointed regular category with finite coproducts and enough projectives, provided the class of projectives is closed under protosplit subobjects, a new condition introduced in this article and naturally satisfied in the abelian context. We further assume that the functor $F$ meets certain exactness conditions: for instance, it may be protoadditive and preserve proper morphisms and binary coproducts—conditions that amount to additivity when $\mathscr {C}$ and $\mathscr {E}$ are abelian categories.

Within this framework, we develop a basic theory of derived functors, compare it with the simplicial approach, and provide several examples.

Marine clay mineral authigenesis, referred to as reverse (silicate) weathering, is one of the first-order controls on seawater pH through the generation of acidity and thus plays a significant role in controlling carbon cycling between marine sediments, oceans and the atmosphere over geological timescales. Reverse weathering is mainly regulated by the rates of silicate and carbonate weathering on the continents, the reactivity of detritus supplied to the oceans and the rates of seafloor weathering. These processes provide essential dissolved components (e.g. K+, Mg2+, Ca2+, Si(OH)4, Al3+, Fe2+/3+) to the marine porewater inventory that cause authigenic clay minerals, such as odinite, glauconite, celadonite and greenalite, to form close to the sediment–seawater interface. Such clay mineral reactions impact the sedimentary cycling versus sequestration of chemical elements, importantly Si, Fe, Mg and K, and consequently contribute to the fluctuations in climate and seawater composition recorded in marine archives over geological time. This review explores the links between reverse silicate weathering and the climate system across geological timescales and provides estimates of the elemental uptake fluxes associated with modern-day clay mineral authigenesis. Novel isotope proxies (e.g. δ41K and δ30Si) and promising new dating techniques (e.g. in situ Rb/Sr geochronology) provide improved constraints on the timing, kinetics and environmental significance of clay mineral reactions on the ocean floor. We also consider recent geoengineering developments linked to reverse weathering reactions, such as ongoing attempts to reduce atmospheric CO2 concentrations via marine alkalinity enhancement and the application of marine clay mineral-based slow-release fertilizers to soils to optimize nutrient availability.

Using the ONEDFEL code we perform free electron laser simulations in the astrophysically important guide-field dominated regime. For wigglers’ (Alfvén waves) wavelengths of tens of kilometres and beam Lorentz factor ${\sim }10^3$, the resulting coherently emitted waves are in the centimetre range. Our simulations show a growth of the wave intensity over fourteen orders of magnitude, over the astrophysically relevant scale of approximately a few kilometres. The signal grows from noise (unseeded). The resulting spectrum shows fine spectral substructures, reminiscent of those observed in fast radio bursts.

Extraintestinal pathogenic Escherichia coli (ExPEC) causes invasive E. coli disease (IED), including bacteraemia and (uro)sepsis, resulting in a high disease burden, especially among older adults. This study describes the epidemiology of IED in England (2013–2017) by combining laboratory surveillance and clinical data. A total of 191 612 IED cases were identified. IED incidence increased annually by 4.4–8.2% across all ages and 2.8–7.6% among adults ≥60 years of age. When laboratory-confirmed urosepsis cases without a positive blood culture were included, IED incidence in 2017 reached 149.4/100 000 person-years among all adults and 368.4/100 000 person-years among adults ≥60 years of age. Laboratory-confirmed IED cases were identified through E. coli-positive blood samples (55.3%), other sterile site samples (26.3%), and urine samples (16.6%), with similar proportions observed among adults ≥60 years of age. IED-associated case fatality rates ranged between 11.8–13.2% among all adults and 13.1–14.7% among adults ≥60 years of age. This study reflects the findings of other published studies and demonstrates IED constitutes a major and growing global health concern disproportionately affecting the older adult population. The high case fatality rates observed despite available antibiotic treatments emphasize the growing urgency for effective intervention strategies. The burden of urosepsis due to E. coli is likely underestimated and requires additional investigation.

Since August 2014, a monitoring survey at a frequency of 111 MHz has been conducted on the Large Phased Array (LPA) radio telescope of the P.N. Lebedev Physical Institute (LPI). We report the discovery of a bright pulse having a dispersion measure (DM) equal to $134.4\pm2\ \text{pc cm}^{-3}$, a peak flux density ($S_p$) equal to $20\pm4$ Jy, and a half-width ($W_e$) equal to $211\pm6$ ms. The excessive DM of the pulse, after taking into account the Milky Way contribution, is $114\ \text{pc cm}^{-3}$ that indicates its extragalactic origin. Such value of DM corresponds to the luminosity distance 713 Mpc. The above parameters make the pulse to be a reliable candidate to the fast radio burst (FRB) event, and then it is the second FRB detected at such a large $\lambda\sim2.7$ m wavelength and the first one among non-repeating FRBs. The normalised luminosity $L_\nu$ of the event, which we have designated as FRB 20190203, estimated under assumption that the whole excessive DM is determined by the intergalactic environment towards the host galaxy, is equal to $\simeq 10^{34}\ \text{erg s}^{-1} \text{Hz}^{-1}$. In addition to the study of radio data we analysed data from the quasi-simultaneous observations of the sky in the high energy ($\geq 80$ keV) band by the omnidirectional detector SPI/ACS aboard the INTEGRAL orbital observatory (in order to look for a possible gamma-ray counterpart of FRB 20190203). We did not detect any transient events exceeding the background at a statistically significant level. In the INTEGRAL archive, the FRB 20190203 localisation region has been observed many times with a total exposure of $\sim 73.2$ days. We have analysed the data but were unable to find any reliable short gamma-ray bursts from the FRB 20190203 position. Finally, we note that the observed properties of FRB 20190203 can be reproduced well in the framework of a maser synchrotron model operating in the far reverse shock (at a distance of $\sim 10^{15}$ cm) of a magnetar. However, triggering the burst requires a high conversion efficiency (at the level of 1%) of the shock wave energy into the radio emission.

The functional diversity structure of a community can be represented as a combination of three additive components (species dominance D, functional redundancy R, and functional diversity Q) (DRQ approach in which different facets of functional differences between species are considered simultaneously). We applied this concept to assemblages of fleas and gamasid mites parasitic on small mammals at continental (across regions of the Palearctic) and regional (across sampling sites in Slovakia) scales and asked: What are the relative effects of host species, biome/habitat type, and geographic locality on the DRQ composition of a parasite assemblage? At the continental scale, regions were partitioned according to predominant biome or geographic position in a continental section. At the regional scale, sampling sites were partitioned according to habitat type or geographic locality. We tested for differences in the functional diversity structure (measured as the DRQ composition) of an ectoparasite assemblage (a) within a host species between biomes/habitat types or continental sections/localities and (b) between host species within a biome/habitat type or a continental section/locality. At both scales, the functional diversity structure of both flea and mite assemblages differed mainly between host species within a biome/habitat or geographic regions/locations, whereas differences in the DRQ composition between biomes/habitats or geographic regions/locations were only detected in a few host species. We compare our results with the results of earlier studies and conclude that the DRQ approach has an advantage over a single diversity metric and allows a better understanding of spatial variation in different facets of ectoparasite diversity.

Paleoparasitological studies have made important contributions to our understanding of the past epidemiology of parasites, infection in past populations and lifestyle in the past. In some cases, these ancient parasites can also provide evidence for long distance travel or migration of people in the past. Three sediment samples from a 15th–16th c. CE latrine from the Spanish nation house in Bruges, Belgium were analysed for preserved helminth eggs using microscopy. Bruges was a major trading centre in medieval Europe, thus it was home to a large merchant population with extensive trading networks. Paleoparasitological analysis revealed a preserved parasite egg from Schistosoma mansoni, which causes intestinal schistosomiasis. Roundworm, whipworm, liver fluke and Taenia tapeworm eggs were also found in the latrine which is consistent with parasites previously found in the local population in the medieval period. These new data provide direct evidence for the movement of S. mansoni outside of its endemic area. Today the vast majority of S. mansoni infections occur in Sub-Saharan Africa, with additional endemic areas in the Arabian peninsula and South America. The introduction of S. mansoni into South America is proposed to have occurred relatively recently in human history, as the result of forced movement of people from Africa to the Americas with the Atlantic slave trade. Thus, this infection may have occurred in a merchant who acquired the parasite during trade voyages to Africa or in an individual living in Africa who migrated to Bruges.

Viruses present an amazing genetic variability. An ensemble of infecting viruses, also called a viral quasispecies, is a cloud of mutants centered around a specific genotype. The simplest model of evolution, whose equilibrium state is described by the quasispecies equation, is the Moran–Kingman model. For the sharp-peak landscape, we perform several exact computations and derive several exact formulas. We also obtain an exact formula for the quasispecies distribution, involving a series and the mean fitness. A very simple formula for the mean Hamming distance is derived, which is exact and does not require a specific asymptotic expansion (such as sending the length of the macromolecules to $\infty$ or the mutation probability to 0). With the help of these formulas, we present an original proof for the well-known phenomenon of the error threshold. We recover the limiting quasispecies distribution in the long-chain regime. We try also to extend these formulas to a general fitness landscape. We obtain an equation involving the covariance of the fitness and the Hamming class number in the quasispecies distribution. Going beyond the sharp-peak landscape, we consider fitness landscapes having finitely many peaks and a plateau-type landscape. Finally, within this framework, we prove rigorously the possible occurrence of the survival of the flattest, a phenomenon which was previously discovered by Wilke et al. (Nature 412, 2001) and which has been investigated in several works (see e.g. Codoñer et al. (PLOS Pathogens 2, 2006), Franklin et al. (Artificial Life 25, 2019), Sardanyés et al. (J. Theoret. Biol. 250, 2008), and Tejero et al. (BMC Evolutionary Biol. 11, 2011)).

Mali is a country where little information is known about the circulation of avian influenza viruses (AIVs) in poultry. Implementing risk-based surveillance strategies would allow early detection and rapid control of AIVs outbreaks in the country. In this study, we implemented a multi-criteria decision analysis (MCDA) method coupled with geographic information systems (GIS) to identify risk areas for AIVs occurrence in domestic poultry in Mali. Five risk factors associated with AIVs occurrence were identified from the literature, and their relative weights were determined using the analytic hierarchy process (AHP). Spatial data were collected for each risk factor and processed to produce risk maps for AIVs outbreaks using a weighted linear combination (WLC). We identified the southeast regions (Bamako and Sikasso) and the central region (Mopti) as areas with the highest risk of AIVs occurrence. Conversely, northern regions were considered low-risk areas. The risk areas agree with the location of HPAI outbreaks in Mali. This study provides the first risk map using the GIS-MCDA approach to identify risk areas for AIVs occurrence in Mali. It should provide a basis for designing risk-based and more cost-effective surveillance strategies for the early detection of avian influenza outbreaks in Mali.

With the over-use of tetracycline (TC) and its ultimate accumulation in aquatic systems, the demand for TC removal from contaminated water is increasing due to its severe threat to public health. Clay minerals have attracted great attention as low-cost adsorbents for controlling water pollution. The objective of the present study was to measure the adsorption behavior and mechanisms of TC on allophane, a nanosized clay mineral with a hollow spherical structure; to highlight the advantage of the allophane nanostructure, a further objective was to compare allophane with halloysite and montmorillonite, which have nanostructures that differ from allophane. Structural features and surface physicochemical properties were characterized by transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), zeta potential, N2-physisorption, and acid–base titration. The adsorption data showed that TC adsorption followed the pseudo-second order and Langmuir models. The adsorption was pH dependent, as all three clay minerals performed better under neutral to weakly alkaline conditions and maintained high adsorption performance in the presence of co-existing Na+/K+/Ca2+/Mg2+ cations. Regeneration of the adsorbent was excellent, with efficiencies exceeding 75% after five recycles. By comparison, allophane always exhibited the greatest adsorption capacity, up to 796 mg g–1 at ~pH 9. The TC adsorption on allophane and halloysite was dominated by inner-sphere complexation, together with a small amount of electrostatic adsorption, while that on montmorillonite involved mainly interlayer cation exchange. The findings provide insights into the effects of nanostructures of clay minerals on their TC adsorption performance and highlight the huge potential of allophane as an efficient and inexpensive adsorbent for TC removal.

The cliff and foreshore sections at Blue Anchor Bay, north Somerset, provide a detailed picture of the transitional Triassic–Jurassic succession. The site has been recorded as a location for fossil fishes for over 200 years, and yet the assemblages from the bone beds have not been described. Here, we present new observations on the two bone beds and find major faunal differences: the classic basal bone bed at Blue Anchor Bay contains an assemblage dominated by osteichthyan teeth, unexpected because elsewhere the ichthyofauna is usually dominated by chondrichthyans. The upper bone bed at Blue Anchor Bay is indeed more typical, being dominated by teeth of hybodont chondrichthyans. We report two unusual finds, first five teeth of the rare shark Parasycylloides turnerae, only the fifth such record in the UK. Further, we report here for the first time a tooth of the pycnodontiform Eomesodon, the first report of this taxon from the Triassic of the UK or Europe. The two bone beds are distinguished not only by different assemblages, but also by evidence of different degrees of anoxia and water depth: the upper bone bed contains abundant pyrite and marcasite, indicating highly anoxic conditions, and perhaps deposition in deeper water than the basal bone bed.