Due to the pressing environmental problems coming from the transport sector, interest in electric vehicles (EVs) has increased significantly over the last decade. Although different types of EVs are ...available on the market, the largest contribution to the reduction of environmental problems could be made through zero‐emission vehicles, such as battery electric vehicles (BEVs) and fuel cell vehicles (FCVs). Each of these vehicles has some advantages and disadvantages. The problem they share is the high purchase price in comparison to conventional gasoline vehicles. Through the improvement of battery performance, further technological learning and a mix of different direct and indirect supporting policy measures, the competiveness of EVs could be significantly improved. EVs could already contribute to the reduction of emissions today, however the full environmental benefit of BEVs and FCVs is related to the mix of the primary energy sources used for electricity generation and hydrogen production. The increasing use of renewable energy sources in electricity generation makes EVs more environmentally friendly. Since total emissions are also dependent on the embedded emissions of cars, their lifetime as well as their usage (specific vehicle kilometers driven per year) have significant impacts on the total emissions per km driven.
The number of demonstration projects with fuel cell buses has been increasing worldwide. The goal of this paper is to analyse prospects and barriers for fuel cell buses focusing on their economic-, ...technical-, and environmental performance. Our results show that the prices of fuel cell buses, although decreasing over time, are still about 40% higher than those of diesel buses. With the looming ban of diesel vehicles, and current limitations of battery electric vehicles, fuel cell buses could become a viable alternative in the mid-to long-term. With the requirements for a better integration of renewable energy sources in the transport system, interest in hydrogen is rising. Hydrogen produced from renewables used in fuel cell buses has the potential to save about 93% of CO2 emissions in comparison to diesel buses. Yet, from environmental point-of-view it has to be ensured that hydrogen is produced from renewables. Currently, the major barrier, for a faster penetration of fuel cell buses are their high purchase prices, which could be significantly reduced with the increasing number of buses through technological learning.
The final conclusion is that a tougher transport policy framework is needed which fully reflects the environmental impact of different buses used.
•Worldwide, buses are the mostly used public transport mode in urban areas.•To reduce GHG emissions diesel buses have to be replaced by zero-emission vehicles.•Major obstacle for fuel cell buses are high investment costs.•The investment costs of green buses could be reduced by technological learning.•Full environmental benefits of fuel cell buses could be reached only in combination with RES.
ABSTRACT We present astrophysical false positive probability calculations for every Kepler Object of Interest (KOI)-the first large-scale demonstration of a fully automated transiting planet ...validation procedure. Out of 7056 KOIs, we determine that 1935 have probabilities <1% of being astrophysical false positives, and thus may be considered validated planets. Of these, 1284 have not yet been validated or confirmed by other methods. In addition, we identify 428 KOIs that are likely to be false positives, but have not yet been identified as such, though some of these may be a result of unidentified transit timing variations. A side product of these calculations is full stellar property posterior samplings for every host star, modeled as single, binary, and triple systems. These calculations use vespa, a publicly available Python package that is able to be easily applied to any transiting exoplanet candidate.
Although deep learning has revolutionized protein structure prediction, almost all experimentally characterized de novo protein designs have been generated using physically based approaches such as ...Rosetta. Here, we describe a deep learning-based protein sequence design method, ProteinMPNN, that has outstanding performance in both in silico and experimental tests. On native protein backbones, ProteinMPNN has a sequence recovery of 52.4% compared with 32.9% for Rosetta. The amino acid sequence at different positions can be coupled between single or multiple chains, enabling application to a wide range of current protein design challenges. We demonstrate the broad utility and high accuracy of ProteinMPNN using x-ray crystallography, cryo-electron microscopy, and functional studies by rescuing previously failed designs, which were made using Rosetta or AlphaFold, of protein monomers, cyclic homo-oligomers, tetrahedral nanoparticles, and target-binding proteins.
ABSTRACT The K2 Mission uses the Kepler spacecraft to obtain high-precision photometry over 80 day campaigns in the ecliptic plane. The Ecliptic Plane Input Catalog (EPIC) provides coordinates, ...photometry, and kinematics based on a federation of all-sky catalogs to support target selection and target management for the K2 mission. We describe the construction of the EPIC, as well as modifications and shortcomings of the catalog. Kepler magnitudes (Kp) are shown to be accurate to 0.1 mag for the Kepler field, and the EPIC is typically complete to Kp 17 (Kp 19 for campaigns covered by Sloan Digital Sky Survey). We furthermore classify 138,600 targets in Campaigns 1-8 ( 88% of the full target sample) using colors, proper motions, spectroscopy, parallaxes, and galactic population synthesis models, with typical uncertainties for G-type stars of 3% in , 0.3 dex in , 40% in radius, 10% in mass, and 40% in distance. Our results show that stars targeted by K2 are dominated by K-M dwarfs ( 41% of all selected targets), F-G dwarfs ( 36%), and K giants ( 21%), consistent with key K2 science programs to search for transiting exoplanets and galactic archeology studies using oscillating red giants. However, we find significant variation of the fraction of cool dwarfs with galactic latitude, indicating a target selection bias due to interstellar reddening and increased contamination by giant stars near the galactic plane. We discuss possible systematic errors in the derived stellar properties, and differences with published classifications for K2 exoplanet host stars. The EPIC is hosted at the Mikulski Archive for Space Telescopes (MAST): http://archive.stsci.edu/k2/epic/search.php.
Extending the differentiation-integration view of organizational design to teams, I propose that self-managing teams engaged in knowledge-intensive work can perform more effectively by combining ...autonomy and external knowledge to capture the benefits of each while offsetting their risks. The complementarity between having autonomy and using external knowledge is contingent, however, on characteristics of the knowledge and the task involved. To test the hypotheses, I examined the strategic and operational effectiveness of 96 teams in a large multinational organization. Findings provide support for the theoretical model and offer implications for research on team ambidexterity and multinational management as well as team effectiveness.
The late pre-Hispanic period in the US Southwest (A.D. 1200–1450) was characterized by large-scale demographic changes, including long-distance migration and population aggregation. To reconstruct ...how these processes reshaped social networks, we compiled a comprehensive artifact database from major sites dating to this interval in the western Southwest. We combine social network analysis with geographic information systems approaches to reconstruct network dynamics over 250 y. We show how social networks were transformed across the region at previously undocumented spatial, temporal, and social scales. Using well-dated decorated ceramics, we track changes in network topology at 50-y intervals to show a dramatic shift in network density and settlement centrality from the northern to the southern Southwest after A.D. 1300. Both obsidian sourcing and ceramic data demonstrate that long-distance network relationships also shifted from north to south after migration. Surprisingly, social distance does not always correlate with spatial distance because of the presence of network relationships spanning long geographic distances. Our research shows how a large network in the southern Southwest grew and then collapsed, whereas networks became more fragmented in the northern Southwest but persisted. The study also illustrates how formal social network analysis may be applied to large-scale databases of material culture to illustrate multigenerational changes in network structure.
Transplantation of livers obtained from donors after circulatory death is associated with an increased risk of nonanastomotic biliary strictures. Hypothermic oxygenated machine perfusion of livers ...may reduce the incidence of biliary complications, but data from prospective, controlled studies are limited.
In this multicenter, controlled trial, we randomly assigned patients who were undergoing transplantation of a liver obtained from a donor after circulatory death to receive that liver either after hypothermic oxygenated machine perfusion (machine-perfusion group) or after conventional static cold storage alone (control group). The primary end point was the incidence of nonanastomotic biliary strictures within 6 months after transplantation. Secondary end points included other graft-related and general complications.
A total of 160 patients were enrolled, of whom 78 received a machine-perfused liver and 78 received a liver after static cold storage only (4 patients did not receive a liver in this trial). Nonanastomotic biliary strictures occurred in 6% of the patients in the machine-perfusion group and in 18% of those in the control group (risk ratio, 0.36; 95% confidence interval CI, 0.14 to 0.94; P = 0.03). Postreperfusion syndrome occurred in 12% of the recipients of a machine-perfused liver and in 27% of those in the control group (risk ratio, 0.43; 95% CI, 0.20 to 0.91). Early allograft dysfunction occurred in 26% of the machine-perfused livers, as compared with 40% of control livers (risk ratio, 0.61; 95% CI, 0.39 to 0.96). The cumulative number of treatments for nonanastomotic biliary strictures was lower by a factor of almost 4 after machine perfusion, as compared with control. The incidence of adverse events was similar in the two groups.
Hypothermic oxygenated machine perfusion led to a lower risk of nonanastomotic biliary strictures following the transplantation of livers obtained from donors after circulatory death than conventional static cold storage. (Funded by Fonds NutsOhra; DHOPE-DCD ClinicalTrials.gov number, NCT02584283.).
The development of a convex probe endobronchial ultrasound (CP-EBUS) videobronchoscope to allow real-time transbronchial needle aspiration (TBNA) has been a significant advance in minimally invasive ...lung cancer staging and diagnosis. Several recent studies have demonstrated CP-EBUS-TBNA to have recovery rivalling that of the current gold standard, cervical mediastinoscopy. These same studies have indicated that the safety of this procedure has no reported complications. The present case study presents two infectious complications from full extension endobronchial ultrasound transbronchial needle aspiration and discusses possible aetiologies of these infections, as well as implications for future application of this technology.
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