356 research outputs found

    A new phylodynamic model of Mycobacterium bovis transmission in a multi-host system uncovers the role of the unobserved reservoir

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    Multi-host pathogens are particularly difficult to control, especially when at least one of the hosts acts as a hidden reservoir. Deep sequencing of densely sampled pathogens has the potential to transform this understanding, but requires analytical approaches that jointly consider epidemiological and genetic data to best address this problem. While there has been considerable success in analyses of single species systems, the hidden reservoir problem is relatively under-studied. A well-known exemplar of this problem is bovine Tuberculosis, a disease found in British and Irish cattle caused by Mycobacterium bovis, where the Eurasian badger has long been believed to act as a reservoir but remains of poorly quantified importance except in very specific locations. As a result, the effort that should be directed at controlling disease in badgers is unclear. Here, we analyse densely collected epidemiological and genetic data from a cattle population but do not explicitly consider any data from badgers. We use a simulation modelling approach to show that, in our system, a model that exploits available cattle demographic and herd-to-herd movement data, but only considers the ability of a hidden reservoir to generate pathogen diversity, can be used to choose between different epidemiological scenarios. In our analysis, a model where the reservoir does not generate any diversity but contributes to new infections at a local farm scale are significantly preferred over models which generate diversity and/or spread disease at broader spatial scales. While we cannot directly attribute the role of the reservoir to badgers based on this analysis alone, the result supports the hypothesis that under current cattle control regimes, infected cattle alone cannot sustain M. bovis circulation. Given the observed close phylogenetic relationship for the bacteria taken from cattle and badgers sampled near to each other, the most parsimonious hypothesis is that the reservoir is the infected badger population. More broadly, our approach demonstrates that carefully constructed bespoke models can exploit the combination of genetic and epidemiological data to overcome issues of extreme data bias, and uncover important general characteristics of transmission in multi-host pathogen systems

    Factors affecting ammonium uptake in streams - an inter-biome perspective

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    The Lotic Intersite Nitrogen experiment (LINX) was a coordinated study of the relationships between North American biomes and factors governing ammonium uptake in streams. Our objective was to relate inter-biome variability of ammonium uptake to physical, chemical and biological processes. 2. Data were collected from 11 streams ranging from arctic to tropical and from desert to rainforest. Measurements at each site included physical, hydraulic and chemical characteristics, biological parameters, whole-stream metabolism and ammonium uptake. Ammonium uptake was measured by injection of \u275~-ammonium and downstream measurements of 15N-ammonium concentration. 3. We found no general, statistically significant relationships that explained the variability in ammonium uptake among sites. However, this approach does not account for the multiple mechanisms of ammonium uptake in streams. When we estimated biological demand for inorganic nitrogen based on our measurements of in-stream metabolism, we found good correspondence between calculated nitrogen demand and measured assimilative nitrogen uptake. 4. Nitrogen uptake varied little among sites, reflecting metabolic compensation in streams in a variety of distinctly different biomes (autotrophic production is high where allochthonous inputs are relatively low and vice versa). 5. Both autotrophic and heterotrophic metabolism require nitrogen and these biotic processes dominate inorganic nitrogen retention in streams. Factors that affect the relative balance of autotrophic and heterotrophic metabolism indirectly control inorganic nitrogen uptake

    Emotion, deliberation, and the skill model of virtuous agency

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    A recent skeptical challenge denies deliberation is essential to virtuous agency: what looks like genuine deliberation is just a post hoc rationalization of a decision already made by automatic mechanisms (Haidt 2001; Doris 2015). Annas’s account of virtue seems well-equipped to respond: by modeling virtue on skills, she can agree that virtuous actions are deliberation-free while insisting that their development requires significant thought. But Annas’s proposal is flawed: it over-intellectualizes deliberation’s developmental role and under-intellectualizes its significance once virtue is acquired. Doing better requires paying attention to a distinctive form of anxiety—one that functions to engage deliberation in the face of decisions that automatic mechanisms alone cannot resolve

    Structural neural networks subserving oculomotor function in first-episode schizophrenia

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    BACKGROUND: Smooth pursuit and antisaccade abnormalities are well documented in schizophrenia, but their neuropathological correlates remain unclear. METHODS: In this study, we used statistical parametric mapping to investigate the relationship between oculomotor abnormalities and brain structure in a sample of first-episode schizophrenia patients (n = 27). In addition to conventional volumetric magnetic resonance imaging, we also used magnetization transfer ratio, a technique that allows more precise tissue characterization. RESULTS: We found that smooth pursuit abnormalities were associated with reduced magnetization transfer ratio in several regions, predominantly in the right prefrontal cortex. Antisaccade errors correlated with gray matter volume in the right medial superior frontal cortex as measured by conventional magnetic resonance imaging but not with magnetization transfer ratio. CONCLUSIONS: These preliminary results demonstrate that specific structural abnormalities are associated with abnormal eye movements in schizophrenia

    Ecological Psychology and Enactivism: A Normative Way Out From Ontological Dilemmas

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    Two important issues of recent discussion in the philosophy of biology and of the cognitive sciences have been the ontological status of living, cognitive agents and whether cognition and action have a normative character per se. In this paper I will explore the following conditional in relation with both the notion of affordance and the idea of the living as self-creation: if we recognize the need to use normative vocabulary to make sense of life in general, we are better off avoiding taking sides on the ontological discussion between eliminativists, reductionists and emergentists. Looking at life through normative lenses is, at the very least, in tension with any kind of realism that aims at prediction and control. I will argue that this is so for two separate reasons. On the one hand, understanding the realm of biology in purely factualist, realist terms means to dispossess it of its dignity: there is more to life than something that we simply aim to manipulate to our own material convenience. On the other hand, a descriptivist view that is committed to the existence of biological and mental facts that are fully independent of our understanding of nature may be an invitation to make our ethical and normative judgments dependent on the discovery of such alleged facts, something I diagnose as a form of representationalism. This runs counter what I take to be a central democratic ideal: while there are experts whose opinion could be considered the last word on purely factual matters, where value is concerned, there are no technocratic experts above the rest of us. I will rely on the ideas of some central figures of early analytic philosophy that, perhaps due to the reductionistic and eliminativist tendencies of contemporary philosophy of mind, have not been sufficiently discussed within post-cognitivist debatesSpanish Government FFI2016-80088-P PID2019-10976RB-100Andalusian government B-HUM459-UGR18FiloLab Group of Excellence, Vicerrectorado de Investigacion, Universidad de Granada (Spain)Departamento de Filosofia I, Universidad de Granad

    Present and future pharmacotherapeutic agents in heart failure: an evolving paradigm

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    Many conditions culminate in heart failure (HF), a multi-organ systemic syndrome with an intrinsically poor prognosis. Pharmacotherapeutic agents that correct neurohormonal dysregulation and haemodynamic instability have occupied the forefront of developments within the treatment of HF in the past. Indeed, multiple trials aimed to validate these agents in the 1980s and early 1990s, resulting in a large and robust evidence-base supporting their use clinically. An established treatment paradigm now exists for the treatment of HF with reduced ejection fraction (HFrEF), but there have been very few notable developments in recent years. HF remains a significant health concern with an increasing incidence as the population ages. We may indeed be entering the surgical era for HF treatment, but these therapies remain expensive and inaccessible to many. Newer pharmacotherapeutic agents are slowly emerging, many targeting alternative therapeutic pathways, but with mixed results. Metabolic modulation and manipulation of the nitrate/nitrite/nitric oxide pathway have shown promise and could provide the answers to fill the therapeutic gap between medical interventions and surgery, but further definitive trials are warranted. We review the significant evidence base behind the current medical treatments for HFrEF, the physiology of metabolic impairment in HF, and discuss two promising novel agents, perhexiline and nitrite

    Knowledge‐How and Epistemic Luck

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    Reductive intellectualists (e.g., Stanley & Williamson 2001; Stanley 2011a; 2011b; Brogaard 2008; 2009; 2011) hold that knowledge-how is a kind of knowledge-that. For this thesis to hold water, it is obviously important that knowledge-how and knowledge-that have the same epistemic properties. In particular, knowledge-how ought to be compatible with epistemic luck to the same extent as knowledge-that. It is argued, contra reductive intellectualism, that knowledge-how is compatible with a species of epistemic luck which is not compatible with knowledge-that, and thus it is claimed that knowledge-how and knowledge-that come apart
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