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Phylogenomic discordance suggests polytomies along the backbone of the large genus Solanum
Get PDFPremise: Evolutionary studies require solid phylogenetic frameworks, but increased volumes of phylogenomic data have revealed incongruent topologies among gene trees in many organisms both between and within genomes. Some of these incongruences indicate polytomies that may remain impossible to resolve. Here we investigate the degree of gene-tree discordance in Solanum, one of the largest flowering plant genera that includes the cultivated potato, tomato, and eggplant, as well as 24 minor crop plants.Methods: A densely sampled species-level phylogeny of Solanum is built using unpublished and publicly available Sanger sequences comprising 60 of all accepted species (742 spp.) and nine regions (ITS, waxy, and seven plastid markers). The robustness of this topology is tested by examining a full plastome dataset with 140 species and a nuclear target-capture dataset with 39 species of Solanum (Angiosperms353 probe set).Key results: While the taxonomic framework of Solanum remained stable, gene tree conflicts and discordance between phylogenetic trees generated from the target-capture and plastome datasets were observed. The latter correspond to regions with short internodal branches, and network analysis and polytomy tests suggest the backbone is composed of three polytomies found at different evolutionary depths. The strongest area of discordance, near the crown node of Solanum, could potentially represent a hard polytomy.Conclusions: We argue that incomplete lineage sorting due to rapid diversification is the most likely cause for these polytomies, and that embracing the uncertainty that underlies them is crucial to understand the evolution of large and rapidly radiating lineages
Geochemistry and paleogeography of the Rajang Group, Northwest Borneo, Malaysia
Get PDFThe Late Cretaceous to Late Eocene Rajang Group in Borneo is one of the world's largest deep-sea sedimentary fans. The volume of the Rajang Group cannot be explained by erosion of the Schwaner Mountains in SW Borneo and the Malay Peninsula. To identify other contributing sources, this study examined the provenance history of the Rajang Group and the overlying Tatau Formation. A combination of bulk rock geochemistry, zircon morphological analysis and U–Pb geochronology is used to better constrain the provenance of the Rajang Group. Bulk rock Nd data, supported by detrital zircon data indicates that a late Mesozoic magmatic belt include the Schwaner Mountains was an important source before the Paleocene, after which sediment supply was dominated by older crustal sources, consistent with the Malay Peninsula. The increased contribution from older crustal material is considered to be the consequence of collapse of the magmatic arc and collision between Australian microcontinental fragment(s) and the southern margin of Sundaland. Paleocene river systems that flowed through the Malay Peninsula, transported large amounts of sediments to the marine basins including the deep-sea Rajang Group. A strong signal of sediment recycling for the Tatau Formation indicates uplift and denudation of lower Rajang Group in Late Eocene
Short communication: An axiomatization of -Quantiles
Get PDFWe give an axiomatic foundation to -quantiles, a family of generalized quantiles introduced in [M. Frittelli, M. Maggis, and I. Peri, Math. Finance, 24 (2014), pp. 442--463] under the name Lambda Value at Risk. Under mild assumptions, we show that these functionals are characterized by a property that we call “locality,” which means that any change in the distribution of the probability mass that arises entirely above or below the value of the -quantile does not modify its value. We make comparisons with a related axiomatization of the usual quantiles given by Chambers in [Math. Finance, 19 (2009), pp. 335--342], based on the stronger property of “ordinal covariance,” meaning that quantiles are covariant with respect to increasing transformations. Further, we present a systematic treatment of the properties of -quantiles, refining some of the results of Frittelli, Maggis, and Peri and [M. Burzoni, I. Peri, and C. M. Ruffo, Quant. Finance, 17 (2017), pp. 1735--1743] and showing that in the case of a nonincreasing the properties of -quantiles closely resemble those of the usual quantiles
Staying poor: unpacking the process of barefoot institutional entrepreneurship failure
Get PDFResearch on barefoot entrepreneurship is growing, yet we still know little about the potential
limits of institutional entrepreneurship in the context of extreme poverty. Challenging
institutional entrepreneurship theory’s agency-centric assumptions, we seek to understand how
barefoot institutional entrepreneurship efforts fail amidst resistance from powerful actors in the
institutional context. Our qualitative study of marginalized waste pickers in Colombia sheds
light on the role of power in barefoot institutional entrepreneurship failure. We unpack a
paradox of inclusion: the more marginalized barefoot entrepreneurs push for and gain
regulatory legitimacy for their market inclusion, the more this accentuates overt and covert
power mechanisms that work to suppress the diffusion of institutional change, aggravating
barefoot entrepreneurs’ market exclusion. Our study shows that while regulatory change is
necessary to enhance barefoot entrepreneurs’ market inclusion, on its own it is not sufficient,
without normative and cognitive support from powerful actors in the institutional field
Prevention, coercion, and two concepts of negative liberty
Get PDFThis paper argues that there are two, irreducibly distinct negative concepts of liberty: freedom as non-prevention and freedom as non-coercion. Contemporary proponents of the negative view, such as Matthew Kramer and Ian Carter, have sought to develop the Hobbesian idea that freedom is essentially a matter of physical non-prevention. Accordingly, they have sought to reduce the freedom-diminishing effect of coercion to that of prevention by arguing that coercive threats function to diminish freedom by preventing people from performing certain combinations of actions. Against this, this paper argues that coercion diminishes people’s freedom in ways that cannot be fully captured in terms of prevention. Focusing on two types of case, those involving coercive threats and those involving coercive preference manipulation, it argues that non-coercion and physical non-prevention are importantly different goods. It concludes that a complete negative account of liberty must draw not only on the (Hobbesian) ‘non-prevention’ strand of the negative tradition but also on its (Benthamite and Hayekian) ‘non-coercion’ strands
Special Issue: Economics in Law: Law in Economics
No full textThis special issue presents a series of papers, each of which – in different ways – reflects upon the role of law in markets. Together, these papers throw light on the ever-evolving relationship between legal studies and the discipline of economics
Body models in humans and robots
Get PDFHumans excel in combining information from multiple sensory modalities, controlling their complex bodies, adapting to growth, failures, or using tools. These capabilities are also highly desirable in robots. They are displayed by machines to some extent—yet, as is so often the case, the artificial creatures are lagging behind. The key foundation is an internal representation of the body that the agent—human or robot—has developed. In the biological realm, evidence has been accumulated by diverse disciplines giving rise to the concepts of body image, body schema, and others. In robotics, a model of the robot is an indispensable component that enables control of the machine. In this chapter, we compare the character of body representations in biology with their robotic counterparts and relate that to the differences in performance that we observe. In some sense, robots have a lot in common with Ian Waterman—“the man who lost his body”—in that they rely on an explicit, veridical body model (body image taken to the extreme) and lack any implicit, multimodal representation (like the body schema) of their bodies. The core of this work is a detailed look at the somatoperceptual processing “pipeline” from inputs (tactile and proprioceptive afference, efferent commands), over “body representations” (superficial schema, postural schema, model of body size and shape), to perceptual processes like spatial localization of touch. A direct comparison with solutions to the same task in robots allows us to make important steps in converting this conceptual schematics into a computational model. As an additional aspect, we briefly look at the question of why robots do not experience body illusions. Finally, we discuss how robots can inform the biological sciences dealing with body representations and which of the features of the “body in the brain” should be transferred to robots, giving rise to more adaptive and resilient, self-calibrating machines
Optimisation techniques for flexible SPARQL queries
Get PDFRDF datasets can be queried using the SPARQL language but are often irregularly structured and incomplete, which may make precise query formulation hard for users. The SPARQL language extends SPARQL 1.1 with two operators - APPROX and RELAX - so as to allow flexible querying over property paths. These operators encapsulate different dimensions of query flexibility, namely approximation and generalisation, and they allow users to query complex, heterogeneous knowledge graphs without needing to know precisely how the data is structured. Earlier work has described the syntax, semantics and complexity of SPARQL, has demonstrated its practical feasibility, but has also highlighted the need for improving the speed of query evaluation. In the present paper, we focus on the design of two optimisation techniques targeted at speeding up the execution of SPARQL queries and on their empirical evaluation on three knowledge graphs: LUBM, DBpedia and YAGO. We show that applying these optimisations can result in substantial improvements in the execution times of longer-running queries (sometimes by one or more orders of magnitude) without incurring significant performance penalties for fast queries
Recommendations to support the mental wellbeing of nurses and midwives in the United Kingdom: a Delphi study
Get PDFAim: To use Delphi technique to identify and prioritise recommendations for research and practice to improve the mental wellbeing of nurses and midwives in the United Kingdom (UK).
Background: Although there is evidence that self-reported mental wellbeing among nurses and midwives in the UK is poor, interventions have not adequately considered the wider context in which they work. The wide range of individual, organisational, occupational, and wider sector-level factors that can influence wellbeing requires the involvement of different stakeholders to identify the most pressing actions required.
Design: A three-round Delphi technique conducted in 2019.
Methods: In the first round, 16 subject matter experts generated, reviewed, and discussed recommendations from a review of the research evidence with potential to support the mental wellbeing of nurses. A second group with 23 stakeholder representatives then rated and provided feedback on the developed recommendations through two additional rounds. Recommendations that received an ‘essential’ or ‘important’ rating from at least 80% of participants were retained and prioritised.
Results: In total, 45 recommendations met the consensus agreement and were retained. More than half (57%) involved action at the organisational level, 27% to public policy and 13% to research. Only one recommendation related to the individual. Collectively, these recommendations highlight the importance of taking direct action to tackle poor mental wellbeing among the workforce and initiating change at the policy and organisational level.
Conclusion: Our findings emphasise the need to take a systemic approach to improving the mental health of nurses and midwives in the UK with input from different stakeholders. There is clear consensus that action is needed at the organisation and policy levels, rather than at the individual level as is current practice.
Impact:
This study provides a framework, alongside a set of practical recommendations, that provides a starting point for different stakeholders to understand, address and support the mental wellbeing of nurses and midwives. Although UK-focused, it has relevance to healthcare workforces internationally
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