Introducing willingness-to-pay for noise changes into transport appraisal: an application of benefit transfer.

Numerous research studies have elicited willingness-to-pay values for transport-related noise, however, in many industrialised countries including the UK, noise costs and benefits are still not incorporated into appraisals for most transport projects and policy changes (Odgaard et al, 2005; Grant-Muller et al, 2001). This paper describes the actions recently taken in the UK to address this issue, comprising: primary research based on the city of Birmingham; an international review of willingness-to-pay evidence; development of values using benefit transfers over time and locations; and integration with appraisal methods. Amongst the main findings are: that the willingness-to-pay estimates derived for the UK are broadly comparable with those used in appraisal elsewhere in Europe; that there is a case for a lower threshold at 1 45dB(A)Leq,18hr1 rather than the more conventional 55dB(A); and that values per dB(A) increase with the noise level above this threshold. There are significant issues over the valuation of rail versus road noise, the neglect of non-residential noise and the valuation of high noise levels in different countries. Conclusions are drawn regarding the feasibility of noise valuation based on benefit transfers in the UK and elsewhere, and future research needs in this field are discussed

Comparing the Performance of Expert User Heuristics and an Integer Linear Program in Aircraft Carrier Deck Operations

Planning operations across a number of domains can be considered as resource allocation problems with timing constraints. An unexplored instance of such a problem domain is the aircraft carrier flight deck, where, in current operations, replanning is done without the aid of any computerized decision support. Rather, veteran operators employ a set of experience based heuristics to quickly generate new operating schedules. These expert user heuristics are neither codified nor evaluated by the United States Navy; they have grown solely from the convergent experiences of supervisory staff. As unmanned aerial vehicles (UAVs) are introduced in the aircraft carrier domain, these heuristics may require alterations due to differing capabilities. The inclusion of UAVs also allows for new opportunities for on-line planning and control, providing an alternative to the current heuristic-based replanning methodology. To investigate these issues formally, we have developed a decision support system for flight deck operations that utilizes a conventional integer linear program-based planning algorithm. In this system, a human operator sets both the goals and constraints for the algorithm, which then returns a proposed schedule for operator approval. As a part of validating this system, the performance of this collaborative human–automation planner was compared with that of the expert user heuristics over a set of test scenarios. The resulting analysis shows that human heuristics often outperform the plans produced by an optimization algorithm, but are also often more conservative

Tracking the international spread of SARS-CoV-2 lineages B.1.1.7 and B.1.351/501Y-V2

Publisher Copyright: © 2021 O'Toole Á et al.Late in 2020, two genetically-distinct clusters of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with mutations of biological concern were reported, one in the United Kingdom and one in South Africa. Using a combination of data from routine surveillance, genomic sequencing and international travel we track the international dispersal of lineages B.1.1.7 and B.1.351 (variant 501Y-V2). We account for potential biases in genomic surveillance efforts by including passenger volumes from location of where the lineage was first reported, London and South Africa respectively. Using the software tool grinch (global report investigating novel coronavirus haplotypes), we track the international spread of lineages of concern with automated daily reports, Further, we have built a custom tracking website (cov-lineages.org/global_report.html) which hosts this daily report and will continue to include novel SARS-CoV-2 lineages of concern as they are detected.Peer reviewe

Diffusion processes in thin tubes and their limits on graphs

The present paper is concerned with diffusion processes running on tubular domains with conditions on nonreaching the boundary, respectively, reflecting at the boundary, and corresponding processes in the limit where the thin tubular domains are shrinking to graphs. The methods we use are probabilistic ones. For shrinking, we use big potentials, respectively, reflection on the boundary of tubes. We show that there exists a unique limit process, and we characterize the limit process by a second-order differential generator acting on functions defined on the limit graph, with Kirchhoff boundary conditions at the vertices.Comment: Published in at http://dx.doi.org/10.1214/11-AOP667 the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org

Can facilitation influence the spatial genetics of the beneficiary plant population?

1. Plant facilitation is a positive interaction where a nurse or nurse plant community alters the local conditions, improving the life-time fitness of other beneficiary plants. In stressful environments, a common consequence is the formation of discrete vegetation patches under nurse plants, surrounded by open space. The consequences of such spatial patterns have been studied mostly at the community level. 2. At the population level, facilitation causes a distribution of beneficiary individuals that could have intra-specific genetic consequences. The spatial patchiness and the increase in local aggregation can potentially affect the population fine-scale genetic structure. In addition, marked microenvironmental differences under nurses versus outside could lead to plastic phenotypic variation between facilitated and non-facilitated individuals, as for example reproductive asynchrony, potentially producing assortative mating. 3. This study tests the hypothesis that plant facilitation can have genetic consequences for the population of a beneficiary plant (Euphorbia nicaeensis) by affecting its spatial genetic structure and mating patterns between subpopulations of facilitated and non-facilitated individuals. 4. Facilitation in this system creates an aggregated distribution of beneficiary individuals compared to a minority of non-facilitated individuals that grow on the open ground. Facilitation also leads to slight phenological differences mediated by strong microenvironmental differences created by nurses compared to the open ground. Yet a molecular analysis showed that, although there is fine scale spatial genetic structure in this system, there is no evidence that it is caused by facilitation. Numerical simulations further showed that spatial genetic patterns in the population are little influenced by the phenological mismatch observed in the field. 5. Synthesis. Facilitation leads to the strong spatial aggregation of beneficiary plants and desynchronizes their flowering phenology, but the magnitude of these effects is not enough to have local genetic consequences in our study system. Facilitation seems thus to have a homogenizing role by allowing the persistence of a diverse gene pool in populations in harsh environments, rather than fomenting genetic differentiation. Further information on other systems where facilitation produces stronger spatial or phenological effects on facilitated plants is needed to fill the large knowledge gap we have on the genetic effects of facilitation

Diversification across the Isthmus of Tehuantepec explains the phylogeographic arrangement of the widespread bright-rumped Attila (Attila spadiceus; Tyrannidae) and reveals the existence of two major lineages

We describe the phylogeographic structure of Attila spadiceus, a neotropical bird with 12 recognized subspecies, through the analysis for partial Cytb amplicon region obtained from 11 subspecies. The topology recovered from the analysis indicated the existence of two principal molecular lineages and that the morphological variation underlying the designation of subspecies is not reflected in the mitochondrial gene tree. Based on these findings, we infer that the diversification of A. spadiceus began at the Pleistocene (similar to 1.5 Mya), with the Isthmus of Tehuantepec region as the main factor driving the formation of two molecular lineages, one to the west and the other one to the east of this geographic barrier.Peer reviewe