Co-introduction of charges on urban roads and motorways in metropolitan areas: a model-based investigation

This paper explores the relationship between charges on motorways and on other types of road. It draws on a model-based study of different pricing scenarios which was conducted within an EU-funded investigation of differentiated infrastructure charges (the DIFFERENT project). The scenarios covered strategies ranging from full charging on all roads irrespective of category, on motorways only, on motorway access roads, on urban roads only, and at cordons. A number of different charge levels were tested. The test results suggested that positive impacts and revenues are maximised by applying charges to each link which reflect the contribution to externalities made by the marginal user of that link - irrespective of whether it is a motorway link or an urban link. However, when implementation costs are taken into account, the best performing scheme was a cordon charge combined with a per-km charge for use of motorways outside the cordon. Fixed per-km charges on motorways or on urban roads are much less effective than charges which are differentiated to reflect congestion on individual links. The introduction of charges only on motorways produces little benefit and causes unwanted diversion to urban roads, and although the introduction of a charge designed to protect the level of service enjoyed by strategic motorway traffic succeeds in achieving that goal, it yields little revenue and has little overall impact on delay or other externalities. The paper highlights the practical implications of these results and notes that, although it is likely to be easier to gain political support for introducing charges on motorways than on other types of road, the benefits from so doing are generally lower than can be obtained by introducing charges on congested urban roads

The Beaker phenomenon and the genomic transformation of northwest Europe

From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain’s gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries

Guidance framework for testing of genetically modified mosquitoes

Reproduced in accordance with the publishers guidelines "The use of content from this health information product for all non-commercial education, training and information purposes is encouraged".Commissioned by TDR and the Foundation for the National Institutes of Health (FNIH), this framework was drafted by four different working groups (efficacy; safety; ethical, legal and social; and regulation), each of which received comments about their draft from experts in the field and the public. Genetically modified mosquitoes (GMM) engineered to be incapable of transmitting certain pathogens or able to reduce populations of similar native mosquito vectors have emerged as a promising new tool to combat vector-borne diseases like malaria and dengue in the more than 100 countries where they’re endemic. The guidance framework aims to foster quality and consistency among processes for testing and regulating new genetic technologies by proposing standards of efficacy and safety testing comparable to those used for trials of other new public health tools. The framework does not represent the views of the World Health Organization (WHO) or FNIH or provide recommendations on what to do. Rather, it is a document that brings together what is known, based on current research evidence, about how best to evaluate GMM

Simulating social-ecological systems: the Island Digital Ecosystem Avatars (IDEA) consortium

Abstract Systems biology promises to revolutionize medicine, yet human wellbeing is also inherently linked to healthy societies and environments (sustainability). The IDEA Consortium is a systems ecology open science initiative to conduct the basic scientific research needed to build use-oriented simulations (avatars) of entire social-ecological systems. Islands are the most scientifically tractable places for these studies and we begin with one of the best known: Moorea, French Polynesia. The Moorea IDEA will be a sustainability simulator modeling links and feedbacks between climate, environment, biodiversity, and human activities across a coupled marine-terrestrial landscape. As a model system, the resulting knowledge and tools will improve our ability to predict human and natural change on Moorea and elsewhere at scales relevant to management/conservation actions

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity.

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant

Ancient pigs reveal a near-complete genomic turnover following their introduction to Europe

Archaeological evidence indicates that pig domestication had begun by ~10,500 y before the present (BP) in the Near East, and mitochondrial DNA (mtDNA) suggests that pigs arrived in Europe alongside farmers ~8,500 y BP. A few thousand years after the introduction of Near Eastern pigs into Europe, however, their characteristic mtDNA signature disappeared and was replaced by haplotypes associated with European wild boars. This turnover could be accounted for by substantial gene flow from local Euro-pean wild boars, although it is also possible that European wild boars were domesticated independently without any genetic con-tribution from the Near East. To test these hypotheses, we obtained mtDNA sequences from 2,099 modern and ancient pig samples and 63 nuclear ancient genomes from Near Eastern and European pigs. Our analyses revealed that European domestic pigs dating from 7,100 to 6,000 y BP possessed both Near Eastern and European nuclear ancestry, while later pigs possessed no more than 4% Near Eastern ancestry, indicating that gene flow from European wild boars resulted in a near-complete disappearance of Near East ancestry. In addition, we demonstrate that a variant at a locus encoding black coat color likely originated in the Near East and persisted in European pigs. Altogether, our results indicate that while pigs were not independently domesticated in Europe, the vast majority of human-mediated selection over the past 5,000 y focused on the genomic fraction derived from the European wild boars, and not on the fraction that was selected by early Neolithic farmers over the first 2,500 y of the domestication process

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant

Population dynamics at a diploid-polyploid contact zone in Mercurialis annua L.

Hybrid zones offer ‘natural laboratories’ for studying the origin, maintenance and demise of species, serving as examples of evolution in action. Understanding the processes that mediate the simultaneous invasions and extinctions of a hybrid zone is therefore essential to understanding the range limits of species and the maintenance of their genetic identity. Populations of diploid (2n = 16) and hexaploid (2n = 48) Mercuralis annua L. s.l. (Euphorbiaceae) have migrated from glacial refugia towards a zone of secondary contact that now exists in north-east Spain. Rapid movement of this zone in favour of the diploids over the past 50 years has been attributed to an interaction of endogenous and exogenous selection, and has lead to the formation of a narrow ‘tension hybrid zone’ that limits the spatial mixing of these lineages. This work systematically disentangles the factors underlying the stability of the diploidhexaploid contact zone in its current position in the north-east Spain to understand the fate of this hybrid zone if it follows its current trajectory into what I have characterised as a low-density trough. I examine the importance of demographic factors such as founding size, reproductive assurance in polyploids, and differences in the rate of seed bank formation for the persistence of both lineages in this area. This provides an estimate of ambient rates of extinction in this zone for each lineage, independent of their interactions with one another, and highlights their susceptibility to density-dependent processes at each life history stage. I then examine asymmetries in hybridisation dynamics between lineages in experimental field populations of controlled density as well as in naturally occurring mixed populations in this zone, assessing the effect of biased gene flow of diploids on the outcome of these apparently rare contact events. I also refine an earlier form of the mass-action pollen pool model to account for the spatial context of individuals and their individual-based contribution to the pollen pool. Using this enables a prediction of hybridisation rates in the field for given mixed assemblages. Results are interpreted in the context of tension zone dynamics and the long-term fate of sexual system variation in this species complex. The identification of long-run negative growth rates in both lineages, and the fact that a small fraction of sites remained by the end of a four-year time course of study, are both indicative of a region that represents a low-density trough into which the diploid-hexaploid contact zone will settle if movement continues along its density-dependent trajectory.This thesis is not currently available in ORA