Density-and trait-mediated effects of a parasite and a predator in a tri-trophic food web

1. Despite growing interest in ecological consequences of parasitism in food webs, relatively little is known about effects of parasites on long-term population dynamics of non-host species or about whether such effects are density- or trait- mediated. 2. We studied a tri-trophic food chain comprised of: (i) a bacterial basal resource (Serratia fonticola), (ii) an intermediate consumer (Paramecium caudatum), (iii) a top predator (Didinium nasutum), and (iv) a parasite of the intermediate consumer (Holospora undulata). A fully-factorial experimental manipulation of predator and parasite presence/absence was combined with analyses of population dynamics, modelling, and analyses of host (Paramecium) morphology and behavior. 3. Predation and parasitism each reduced the abundance of the intermediate consumer (Paramecium), and parasitism indirectly reduced the abundance of the basal resource (Serratia). However, in combination, predation and parasitism had non-additive effects on the abundance of the intermediate consumer, as well as on that of the basal resource. In both cases, the negative effect of parasitism seemed to be effaced by predation. 4. Infection of the intermediate consumer reduced predator abundance. Modelling and additional experimentation revealed that this was most likely due to parasite reduction of intermediate host abundance (a density-mediated effect), as opposed to changes in predator functional or numerical response. 5. Parasitism altered morphological and behavioural traits, by reducing host cell length and increasing the swimming speed of cells with moderate parasite loads. Additional tests showed no significant difference in Didinium feeding rate on infected and uninfected hosts, suggesting that the combination of these modifications does not affect host vulnerability to predation. However, estimated rates of encounter with Serratia based on these modifications were higher for infected Paramecium than for uninfected Paramecium. 6. A mixture of density-mediated and trait-mediated indirect effects of parasitism on non- host species creates rich and complex possibilities for effects of parasites in food webs that should be included in assessments of possible impacts of parasite eradication or introduction

The first poverty line? Davies and Eden’s investigation of rural poverty in late 18th-century England

Two important and well-known surveys of the household budgets of the English rural labouring poor were produced by David Davies and Frederick Eden in the 1790s. We revisit these from the point of view of their original rationale — an investigation of the characteristics and extent of poverty in the countryside. We argue that Davies' standard of ‘tolerable comfort’ can lay claim to being the first poverty line based upon the application of a minimum consumption standard to household income. We find that the majority of households fall below this standard, although those in the south of England were worst off, that family size was the largest coefficient and poverty reduced as the age of the first child increased. The incidence of poverty was not highly correlated with the absence of a woman wage earner

Unconventional localization of electrons inside of a nematic electronic phase

The magnetotransport behaviour inside the nematic phase of bulk FeSe reveals unusual multiband effects that cannot be reconciled with a simple two-band approximation proposed by surface-sensitive spectroscopic probes. In order to understand the role played by the multiband electronic structure and the degree of two-dimensionality we have investigated the electronic properties of exfoliated flakes of FeSe by reducing their thickness. Based on magnetotransport and Hall resistivity measurements, we assess the mobility spectrum that suggests an unusual asymmetry between the mobilities of the electrons and holes with the electron carriers becoming localized inside the nematic phase. Quantum oscillations in magnetic fields up to 38 T indicate the presence of a hole-like quasiparticle with a lighter effective mass and a quantum scattering time three times shorter, as compared with bulk FeSe. The observed localization of negative charge carriers by reducing dimensionality can be driven by orbitally-dependent correlation effects, enhanced interband spin-fluctuations or a Lifshitz-like transition which affect mainly the electron bands. The electronic localization leads to a fragile two-dimensional superconductivity in thin flakes of FeSe, in contrast to the two-dimensional high-Tc induced with electron doping via dosing or using a suitable interface.Comment: 22 pages, 14 figure

Investigating mechanisms of state localization in highly ionized dense plasmas

Producción CientíficaWe present experimental observations of Kβ emission from highly charged Mg ions at solid density, driven by intense x rays from a free electron laser. The presence of Kβ emission indicates the n=3 atomic shell is relocalized for high charge states, providing an upper constraint on the depression of the ionization potential. We explore the process of state relocalization in dense plasmas from first principles using finite-temperature density functional theory alongside a wave-function localization metric, and find excellent agreement with experimental results.This work has been supported by the Spanish Ministry of Science and Innovation under Research Grant No. PID2019-108764RB-I0

Investigating Mechanisms of State Localization in Highly-Ionized Dense Plasmas

We present the first experimental observation of K$_{\beta}$ emission from highly charged Mg ions at solid density, driven by intense x-rays from a free electron laser. The presence of K$_{\beta}$ emission indicates the $n=3$ atomic shell is relocalized for high charge states, providing an upper constraint on the depression of the ionization potential. We explore the process of state relocalization in dense plasmas from first principles using finite-temperature density functional theory alongside a wavefunction localization metric, and find excellent agreement with experimental results.Comment: 22 pages, 13 figure

Urban working-class food consumption and nutrition in Britain in 1904

This article re-examines the food consumption of working class households in 1904 and compares the nutritional content of these diets with modern measures of adequacy. We find a fairly steep gradient of nutritional attainment relative to economic class, with high levels of vitamin and mineral deficiency among the very poorest working households. We conclude that the average unskilled-headed working household was better fed and nourished than previously thought. When proper allowance is made for the likely consumption of alcohol, household energy intakes were significantly higher still. We investigate the likely impact of contemporary cultural food distribution norms and conclude on the basis of the very limited evidence available that women may have received, on average, about 80% of a man’s share of the available food. We adjust energy requirements for likely higher physical activity rates and smaller stature and find that except among the poorest households, early twentieth century diets were sufficient to provide energy for reasonably physically demanding work. These results are consistent with recent attempts to relate the available anthropometric evidence to long-run trends in food consumption. We also find that the lower tail of the household nutrition distribution drops away very rapidly, so that few households are estimated to have suffered severe food shortages. JEL Classification: I14, I32, N34 Keywords: nutrition, well-being, Britain, early 20th century

Kidney single-cell atlas reveals myeloid heterogeneity in progression and regression of kidney disease

BACKGROUND: Little is known about the roles of myeloid cell subsets in kidney injury and in the limited ability of the organ to repair itself. Characterizing these cells based only on surface markers using flow cytometry might not provide a full phenotypic picture. Defining these cells at the single-cell, transcriptomic level could reveal myeloid heterogeneity in the progression and regression of kidney disease. METHODS: Integrated droplet– and plate-based single-cell RNA sequencing were used in the murine, reversible, unilateral ureteric obstruction model to dissect the transcriptomic landscape at the single-cell level during renal injury and the resolution of fibrosis. Paired blood exchange tracked the fate of monocytes recruited to the injured kidney. RESULTS: A single-cell atlas of the kidney generated using transcriptomics revealed marked changes in the proportion and gene expression of renal cell types during injury and repair. Conventional flow cytometry markers would not have identified the 12 myeloid cell subsets. Monocytes recruited to the kidney early after injury rapidly adopt a proinflammatory, profibrotic phenotype that expresses Arg1, before transitioning to become Ccr2(+) macrophages that accumulate in late injury. Conversely, a novel Mmp12(+) macrophage subset acts during repair. CONCLUSIONS: Complementary technologies identified novel myeloid subtypes, based on transcriptomics in single cells, that represent therapeutic targets to inhibit progression or promote regression of kidney disease

Electron population dynamics in resonant non-linear x-ray absorption in nickel at a free-electron laser

Free-electron lasers provide bright, ultrashort, and monochromatic x-ray pulses, enabling novel spectroscopic measurements not only with femtosecond temporal resolution: The high fluence of their x-ray pulses can also easily enter the regime of the non-linear x-ray–matter interaction. Entering this regime necessitates a rigorous analysis and reliable prediction of the relevant non-linear processes for future experiment designs. Here, we show non-linear changes in the L3-edge absorption of metallic nickel thin films, measured with fluences up to 60 J/cm2. We present a simple but predictive rate model that quantitatively describes spectral changes based on the evolution of electronic populations within the pulse duration. Despite its simplicity, the model reaches good agreement with experimental results over more than three orders of magnitude in fluence, while providing a straightforward understanding of the interplay of physical processes driving the non-linear changes. Our findings provide important insights for the design and evaluation of future high-fluence free-electron laser experiments and contribute to the understanding of non-linear electron dynamics in x-ray absorption processes in solids at the femtosecond timescale

Codesigning a Measure of Person-Centred Coordinated Care to Capture the Experience of the Patient: The Development of the P3CEQ

Background: Person-centred coordinated care (P3C) is a priority for stakeholders (ie, patients, carers, professionals, policy makers). As a part of the development of an evaluation framework for P3C, we set out to identify patient-reported experience measures (PREMs) suitable for routine measurement and feedback during the development of services. Methods: A rapid review of the literature was undertaken to identity existing PREMs suitable for the probing person-centred and/or coordinated care. Of 74 measures identified, 7 met our inclusion criteria. We critically examined these against core domains and subdomains of P3C. Measures were then presented to stakeholders in codesign workshops to explore acceptability, utility, and their strengths/weaknesses. Results: The Long-Term Condition 6 questionnaire was preferred for its short length, utility, and tone. However, it lacked key questions in each core domain, and in response to requests from our codesign group, new questions were added to cover consideration as a whole person, coordination, care plans, carer involvement, and a single coordinator. Cognitive interviews, on-going codesign, and mapping to core P3C domains resulted in the refinement of the questionnaire to 11 items with 1 trigger question. The 11-item modified version was renamed the P3C Experiences Questionnaire. Conclusions: Due to a dearth of brief measures available to capture people’s experience of P3C for routine practice, an existing measure was modified using an iterative process of adaption and validation through codesign workshops. Next steps include psychometric validation and modification for people with dementia and learning difficulties.</p