The bicycle is a low-cost means of transport linked to low risk of transmission of infectious disease. During the COVID-19 crisis, governments have therefore incentivized cycling by provisionally ...redistributing street space. We evaluate the impact of this new bicycle infrastructure on cycling traffic using a generalized difference in differences design. We scrape daily bicycle counts from 736 bicycle counters in 106 European cities. We combine these with data on announced and completed pop-up bike lane road work projects. Within 4 mo, an average of 11.5 km of provisional pop-up bike lanes have been built per city and the policy has increased cycling between 11 and 48% on average. We calculate that the new infrastructure will generate between $1 and $7 billion in health benefits per year if cycling habits are sticky.
The price of EU allowances (EUAs) in the EU Emissions Trading Scheme (EU ETS) fell from almost 30€/tCO2 in mid-2008 to less than 5€/tCO2 in mid-2013. The sharp and persistent price decline has ...sparked intense debates both in academia and among policy-makers about the decisive allowance price drivers. In this paper we examine whether and to what extent the EUA price drop can be justified by three commonly identified explanatory factors: the economic recession, renewable policies and the use of international credits. Capitalizing on marginal abatement cost theory and a broadly extended data set, we find that only variations in economic activity and the growth of wind and solar electricity production are robustly explaining EUA price dynamics. Contrary to simulation-based analyses, our results point to moderate interaction effects between the overlapping EU ETS and renewable policies. The bottom line, however, is that 90% of the variations of EUA price changes remains unexplained by the abatement-related fundamentals. Together, our findings do not support the widely-held view that negative demand shocks are the main cause of the weak carbon price signal. In view of the new evidence, we evaluate the EU ETS reform options which are currently discussed.
•We examine whether abatement-related fundamentals justify the EU ETS price drop.•90% of the variations of EUA price changes remain unexplained.•Variations in economic activity are robustly explaining EUA price dynamics.•Price impact of renewable deployment and international credit use remains moderate.•Reform options are evaluated in the light of the new findings.
This study exploits the incomplete participation requirements of the European Union Emissions Trading System (EU ETS) to investigate the policy's causal effect on outward foreign direct investment ...(FDI) decisions of German multinational firms. Using a combination of difference-in-differences with bias-corrected matching, our baseline specification indicates that the sample average treatment effect is very small and levels out at −0.2%, but its standard error is large (0.16). Looking at a sub-sample of firms which can be considered as geographically more mobile because they are supposedly less capital-intensive, we find that a small number of EU ETS regulated firms have increased their FDI outside the EU by 52% ± 47% compared to a counterfactual scenario. Paradoxically, relocating firms neither operate in the targeted energy-intensive sectors, nor are they emission-intensive. The small emissions share of these footloose firms indeed indicates a limited potential for policy-induced leakage of emissions. On the extensive margin, we find that all EU ETS firms on average have increased the number of their affiliates outside the EU by 28% ± 24% relative to control firms. This causal change in network structures of multinational firms outside the EU is suggestive of endeavors undertaken by regulated firms to facilitate relocations in the future.
•We examine causal effect of the EU ETS on outward FDI decisions of German multinationals.•The treatment effect from a matched difference-in-differences design levels out at -0.2% and is statistically insignificant.•Yet, a comparatively small number of firms have shifted part of their production to non-EU ETS countries.•Relocating firms neither operate in the targeted energy-intensive sectors, nor are they emission-intensive.•They are rather firms in shortage of permits operating in footloose sectors, making leakage of emissions hardly possible.
The impact of different feed waters in terms of eukaryotic populations and organic carbon content on the biofilm structure formation and permeate flux during Gravity-Driven Membrane (GDM) filtration ...was investigated in this study. GDM filtration was performed at ultra-low pressure (65 mbar) in dead-end mode without control of the biofilm formation. Different feed waters were tested (River water, pre-treated river water, lake water, and tap water) and varied with regard to their organic substrate content and their predator community. River water was manipulated either by chemically inhibiting all eukaryotes or by filtering out macrozoobenthos (metazoan organisms). The structure of the biofilm was characterized at the meso- and micro-scale using Optical Coherence Tomography (OCT) and Confocal Laser Scanning Microscopy (CLSM), respectively. Based on Total Organic Carbon (TOC) measurements, the river waters provided the highest potential for bacterial growth whereas tap water had the lowest. An increasing content in soluble and particulate organic substrate resulted in increasing biofilm accumulation on membrane surface. However, enhanced biofilm accumulation did not result in lower flux values and permeate flux was mainly influenced by the structure of the biofilm. Metazoan organisms (in particular nematodes and oligochaetes) built-up protective habitats, which resulted in the formation of open and spatially heterogeneous biofilms composed of biomass patches. In the absence of predation by metazoan organisms, a flat and compact biofilm developed. It is concluded that the activity of metazoan organisms in natural river water and its impact on biofilm structure balances the detrimental effect of a high biofilm accumulation, thus allowing for a broader application of GDM filtration. Finally, our results suggest that for surface waters with high particulate organic carbon (POC) content, the use of worms is suitable to enhance POC removal before ultrafiltration units.
Display omitted
► Increasing TOC content in the influent induces a lower permeate flux. ► In the absence of metazoa, influent TOC content governs biofilm accumulation. ► In the absence of metazoa flat and compacts biofilms form. ► Metazoan activity induces the formation of open and heterogeneous biofilms. ► Metazoan activity increases biofilm permeability, and in turn the permeate flux.
Abstract
Phylogenomic subsampling is a procedure by which small sets of loci are selected from large genome-scale data sets and used for phylogenetic inference. This step is often motivated by either ...computational limitations associated with the use of complex inference methods or as a means of testing the robustness of phylogenetic results by discarding loci that are deemed potentially misleading. Although many alternative methods of phylogenomic subsampling have been proposed, little effort has gone into comparing their behavior across different data sets. Here, I calculate multiple gene properties for a range of phylogenomic data sets spanning animal, fungal, and plant clades, uncovering a remarkable predictability in their patterns of covariance. I also show how these patterns provide a means for ordering loci by both their rate of evolution and their relative phylogenetic usefulness. This method of retrieving phylogenetically useful loci is found to be among the top performing when compared with alternative subsampling protocols. Relatively common approaches such as minimizing potential sources of systematic bias or increasing the clock-likeness of the data are found to fare worse than selecting loci at random. Likewise, the general utility of rate-based subsampling is found to be limited: loci evolving at both low and high rates are among the least effective, and even those evolving at optimal rates can still widely differ in usefulness. This study shows that many common subsampling approaches introduce unintended effects in off-target gene properties and proposes an alternative multivariate method that simultaneously optimizes phylogenetic signal while controlling for known sources of bias.
The environment has an influence on an organism's growth and differentiation during ontogeny. For extinct species in particular, the record of this interaction can be accessed through osteohistology. ...Such studies have, however, historically focused largely on dinosaurs and mammals, leaving the rest of Amniota understudied. Although accounting for nearly 40% of extant amniote diversity, Squamata (hereafter, “lizards” including snakes and amphisbaenians) is conspicuous for lack of osteohistological study. Here, an osteohistological study of the growth record of 29 individuals of the cnemidophorine teiid lizard Aspidoscelis tigris – Tiger whiptail – sheds light on the species’ growth patterns. We observed that size and age are not tightly coupled in A. tigris. Rather, growth in this lizard may be influenced by genetically determined growth strategies suited to the highly variable arid environments they inhabit, in conjunction with the environment in which individuals hatch. Hatchlings, which exhibit the highest growth rates, have the smallest home ranges and thus habitat variables such as the density of food and competitors could strongly influence final size. However, smaller size seems to favor longevity in A. tigris as the oldest individuals are below the median snout-vent length for the species. Surprisingly, ‘adult’ ontogenetic fusions in the skeleton did not correlate closely with age. Instead, they strongly correlate with size. Although a terminal asymptotic size appears fixed within a narrow size range, the rate at which they achieve it is highly variable. Our study reveals a complex organism-environment interaction governing growth and differentiation in Aspidoscelis tigris, that has implications for the interpretation of osteohistological data in fossil taxa.
•Age and size in Aspidoscelis tigris are not strongly correlated.•Growth in the first two seasons strongly correlates with final size.•Temperature positively influences growth in the first season, precipitation has a negative influence.•Suture fusion correlates with size, not with age.•Sutures and growth record combined allow for accurate life-history reconstruction.
Squamate reptiles are a major component of vertebrate biodiversity whose crown-clade traces its origin to a narrow window of time in the Mesozoic during which the main subclades diverged in rapid ...succession. Deciphering phylogenetic relationships among these lineages has proven challenging given the conflicting signals provided by genomic and phenomic data. Most notably, the placement of Iguania has routinely differed between data sources, with morphological evidence supporting a sister relationship to the remaining squamates (Scleroglossa hypothesis) and molecular data favoring a highly nested position alongside snakes and anguimorphs (Toxicofera hypothesis). We provide novel insights by generating an expanded morphological dataset and exploring the presence of phylogenetic signal, noise, and biases in molecular data. Our analyses confirm the presence of strong conflicting signals for the position of Iguania between morphological and molecular datasets. However, we also find that molecular data behave highly erratically when inferring the deepest branches of the squamate tree, a consequence of limited phylogenetic signal to resolve this ancient radiation with confidence. This, in turn, seems to result from a rate of evolution that is too high for historical signals to survive to the present. Finally, we detect significant systematic biases, with iguanians and snakes sharing faster rates of molecular evolution and a similarly biased nucleotide composition. A combination of scant phylogenetic signal, high levels of noise, and the presence of systematic biases could result in the misplacement of Iguania. We regard this explanation to be at least as plausible as the complex scenario of convergence and reversals required for morphological data to be misleading. We further evaluate and discuss the utility of morphological data to resolve ancient radiations, as well as its impact in combined-evidence phylogenomic analyses, with results relevant for the assessment of evidence and conflict across the Tree of Life.
Today, more than 70 carbon pricing schemes have been implemented around the globe, but their contributions to emissions reductions remains a subject of heated debate in science and policy. Here we ...assess the effectiveness of carbon pricing in reducing emissions using a rigorous, machine-learning assisted systematic review and meta-analysis. Based on 483 effect sizes extracted from 80 causal ex-post evaluations across 21 carbon pricing schemes, we find that introducing a carbon price has yielded immediate and substantial emission reductions for at least 17 of these policies, despite the low level of prices in most instances. Statistically significant emissions reductions range between -5% to -21% across the schemes (-4% to -15% after correcting for publication bias). Our study highlights critical evidence gaps with regard to dozens of unevaluated carbon pricing schemes and the price elasticity of emissions reductions. More rigorous synthesis of carbon pricing and other climate policies is required across a range of outcomes to advance our understanding of "what works" and accelerate learning on climate solutions in science and policy.
Adaptive landscapes are a common way of conceptualizing the phenotypic evolution of lineages across deep time. Although multiple approaches exist to implement this concept into operational models of ...trait evolution, inferring adaptive landscapes from comparative datasets remains challenging. Here, I explore the macroevolutionary dynamics of echinoid body size using data from over 5000 specimens and a phylogenetic framework incorporating a dense fossil sampling and spanning approximately 270 million years. Furthermore, I implement a novel approach of exploring alternative parameterizations of adaptive landscapes that succeeds in finding simpler, yet better-fitting models. Echinoid body size has been constrained to evolve within a single adaptive optimum for much of the clade’s history. However, most of the morphological disparity of echinoids was generated by multiple regime shifts that drove the repeated evolution of miniaturized and gigantic forms. Events of body size innovation occurred predominantly in the Late Cretaceous and were followed by a drastic slowdown following the Cretaceous-Paleogene mass extinction. The discovery of these patterns is contingent upon directly sampling fossil taxa. The macroevolution of echinoid body size is therefore characterized by a late increase in disparity (likely linked to an expansion of ecospace), generated by active processes driving lineages toward extreme morphologies.
PDF
