342 research outputs found
Climate Change Adaptation Case Study: Benefit-Cost Analysis of Coastal Flooding Hazard Mitigation
The damage Hurricane Sandy caused had far-reaching repercussions up and down the East Coast of the United States. Vast coastal flooding accompanied the storm, inundating homes, businesses, and utility and emergency facilities. Since the storm, projects to mitigate similar future floods have been scrutinized. Such projects not only need to keep out floodwaters but also be designed to withstand the effect that climate change might have on rising sea levels and increased flood risk.
In this study, we develop an economic model to assess the costs and benefits of a berm (sea wall) to mitigate the effects of flooding from a large storm. We account for the lifecycle costs of the project, which include those for the upfront construction of the berm, ongoing maintenance, land acquisition, and wetland and recreation zone construction. Benefits of the project include avoided fatalities, avoided residential and commercial damages, avoided utility and municipal damages, recreational and health benefits, avoided debris removal expenses, and avoided loss of function of key transportation and commercial infrastructure located in the area. Our estimate of the beneficial effects of the berm includes ecosystem services from wetlands and health benefits to the surrounding community from a park and nature system constructed along the berm.
To account for the effects of climate change and verify that the project will maintain its effectiveness over the long term, we allow the risk of flooding to increase over time. Over our 50-year time horizon, we double the risk of 100- and 500-year flood events to account for the effects of sea level rise on coastal flooding. Based on the economic analysis, the project is highly cost beneficial over its 50-year timeframe. This analysis demonstrates that climate change adaptation investments can be cost beneficial even though they mitigate the impacts of low-probability, high-consequence events
Detecting Molecular Rotational Dynamics Complementing the Low-Frequency Terahertz Vibrations in a Zirconium-Based Metal-Organic Framework
We show clear experimental evidence of co-operative terahertz (THz) dynamics
observed below 3 THz (~100 cm-1), for a low-symmetry Zr-based metal-organic
framework (MOF) structure, termed MIL-140A [ZrO(O2C-C6H4-CO2)]. Utilizing a
combination of high-resolution inelastic neutron scattering and synchrotron
radiation far-infrared spectroscopy, we measured low-energy vibrations
originating from the hindered rotations of organic linkers, whose energy
barriers and detailed dynamics have been elucidated via ab initio density
functional theory (DFT) calculations. For completeness, we obtained Raman
spectra and characterized the alterations to the complex pore architecture
caused by the THz rotations. We discovered an array of soft modes with
trampoline-like motions, which could potentially be the source of anomalous
mechanical phenomena, such as negative linear compressibility and negative
thermal expansion. Our results also demonstrate coordinated shear dynamics
(~2.5 THz), a mechanism which we have shown to destabilize MOF crystals, in the
exact crystallographic direction of the minimum shear modulus (Gmin).Comment: 10 pages, 6 figure
BOUND OBJECT HIERARCHY SERVICE
Presented herein is a hierarchical representation of uniquely identified objects within the physical world, referred to as a âBound Object Hierarchy Service.â The Bound Object Hierarchy Service enables the synchronous shared view and creation of digital twins among coordinating entities. The system enables the representation and policy based access to objects, mapped from the physical world, that would typically be considered to follow a âbound withinâ hierarchy. The digital custody and ownership of the physical objects can autonomously change over time within the system (e.g., as an object passes along a supply chain, determined via sensors within the environment and policy based access). The policy based approach can additionally enable third parties or a limited set of the system participants to access the object hierarchy data in order to view specific elements of the tracked objects, along with the sharing of object sensor data
Feldexperiment zur Wirksamkeit von konkretem vs. abstraktem Eco-Driving Feedback
Eco-Driving Feedback Informationssysteme haben das Potenzial, auf sehr rasche und effiziente Weise zur Reduktion von Spritverbrauch und CO2 im Strassentransportwesen beizutragen. Vor allem neuere vernetzte Fahrzeuge bieten durch die zunehmende Digitalisierung der Cockpits viel Freiraum zur Gestaltung und Untersuchung von Eco-Driving Feedback. Neben klassischen âSpritverbrauchs-Tachos findet man heutzutage auch eher abstrakte Formen der Informationsdarbietung, z.B. animierte Pflanzen, die in AbhĂ€ngigkeit vom Spritverbrauch wachsen oder schrumpfen. Diese Möglichkeiten werfen wichtige Fragen auf: Welche Art der Informationsdarbietung Ă€ndert das Fahrverhalten kurzfristig und langfristig effektiver? Welche Fahrverhaltensweisen (z.B. Bremsverhalten) werden in welchem Masse beeinflusst? HĂ€ngen eventuelle Effekte von bestimmten Moderatoren ab? Um diese Fragen zu untersuchen, wurde ein Eco-Driving Feedback System entwickelt, welches den Spritverbrauch des Fahrzeugs auf klassisch âkonkrete Art einerseits und auf eher abstrakte Art andererseits anzeigt. Die Auswirkungen auf Fahrverhalten und Spritverbrauch sollen in einem Feldexperiment unter Alltagsbedingungen mit 72 Pannenservice-Fahrern untersucht werden
Recommended from our members
Observed aerosol characteristics to improve forward-modelled attenuated backscatter in urban areas
Numerical weather prediction (NWP) models often parameterise aerosols to reduce computational needs, while aiming to accurately capture their impact adequately. Increasingly, aerosols are monitored in-situ directly and/or indirectly (e.g. by automatic lidars and ceilometers, ALC). ALC measure the aerosol optical characteristic of attenuated backscatter. This can also be estimated using forward models that combine forecast aerosol and relative humidity to parameterise aerosol physical and optical characteristics. The aerFO is one such forward model, designed to use Met Office NWP model output and parameterisations from the MURK visibility scheme. Given the aerFO-MURK scheme link, assessing the aerFO and its output could therefore be used to inform future developments of the MURK scheme. To identify which parameterised physical and optical aerosol characteristics in the scheme are the most critical in urban settings, aerFO is driven with different in-situ aerosol observations at a background site in central London. Estimated attenuated backscatter is then assessed against ALC observations. It is shown that the original MURK scheme parameterisation underestimates the variance of both dry mean volume radius and total number concentration. Representing both the accumulation and coarse mode aerosols in the aerFO reduces the median bias error of estimated attenuated backscatter by 69.1 %. Providing more realistic temporal (monthly to hourly) variability of relative mass for different species leads to little improvement, compared to using monthly climatological means. Numerical experiments show that having more realistic estimates of number concentration is more important than providing more accurate values of the dry mean volume radius for the accumulation mode. Hence, improving the parameterisations for number concentration should be a main focus for further development of the MURK scheme. To estimate aerosol attenuated backscatter, the aerFO requires an extinction to backscatter ratio (i.e. the lidar ratio). In addition to forward modelling, the lidar ratio can also be used with ALC attenuated backscatter to calculate aerosol properties estimated in aerosol forecasts. Here, a model is developed that estimates the ratio using in-situ observations of the number size distribution and speciated aerosol masses. The values of lidar ratio derived at the London background site (14 â 80 sr across selected common lidar wavelengths) compare well to the literature. However, the modelled lidar ratio is unexpectedly correlated to relative humidity. Further, a stronger dependence exists at shorter wavelengths (355 and 532 nm) compared to longer wavelengths (905 and 1064 nm), and is due to the critical relation of lidar wavelength to aerosol size.
Keywords: urban aerosols; lidar forward operator; automatic lidar and ceilometers; urban observation network; lidar rati
Mapping Obscured Star Formation in the Host Galaxy of FRB 20201124A
We present high-resolution 1.5--6 GHz Karl G. Jansky Very Large Array (VLA)
and () optical and infrared
observations of the extremely active repeating fast radio burst (FRB)
FRB20201124A and its barred spiral host galaxy. We constrain the location
and morphology of star formation in the host and search for a persistent radio
source (PRS) coincident with FRB20201124A. We resolve the morphology of the
radio emission across all frequency bands and measure a star formation rate SFR
yr, a factor of larger than
optically-inferred SFRs, demonstrating dust-obscured star formation throughout
the host. Compared to a sample of all known FRB hosts with radio emission, the
host of FRB20201124A has the most significant obscured star formation.
While observations show the FRB to be offset from the bar or spiral
arms, the radio emission extends to the FRB location. We propose that the FRB
progenitor could have formed (e.g., a magnetar central
engine born from the explosion of a massive star). It is still plausible,
although less likely, that the progenitor of FRB20201124A migrated from the
central bar of the host, e.g., via a runaway massive star. We further place a
limit on the luminosity of a putative PRS at the FRB position of $L_{\rm 6.0 \
GHz}\lesssim\times10^{27}^{-1}^{-1}\gtrsim 10^{5}$
yr in each model, respectively.Comment: 21 pages, 6 figures, 3 tables, Submitte
Recommended from our members
Strategic treatment optimization for HCV (STOPHCV1): a randomised controlled trial of ultrashort duration therapy for chronic hepatitis C
Background: The world health organization (WHO) has identified the need for a better understanding of which patients with hepatitis C virus (HCV) can be cured with ultrashort course HCV therapy.
Methods: A total of 202 individuals with chronic HCV were randomised to fixed-duration shortened therapy (8 weeks) vs variable-duration ultrashort strategies (VUS1/2). Participants not cured following first-line treatment were retreated with 12 weeksâ sofosbuvir/ledipasvir/ribavirin. The primary outcome was sustained virological response 12 weeks (SVR12) after first-line treatment and retreatment. Participants were factorially randomised to receive ribavirin with first-line treatment.
Results: All evaluable participants achieved SVR12 overall (197/197, 100% [95% CI 98-100]) demonstrating non-inferiority between fixed-duration and variable-duration strategies (difference 0% [95% CI -3.8%, +3.7%], 4% pre-specified non-inferiority margin). First-line SVR12 was 91% [86%-97%] (92/101) for fixed-duration vs 48% [39%-57%] (47/98) for variable-duration, but was significantly higher for VUS2 (72% [56%-87%] (23/32)) than VUS1 (36% [25%-48%] (24/66)). Overall, first-line SVR12 was 72% [65%-78%] (70/101) without ribavirin and 68% [61%-76%] (69/98) with ribavirin (p=0.48). At treatment failure, the emergence of viral resistance was lower with ribavirin (12% [2%-30%] (3/26)) than without (38% [21%-58%] (11/29), p=0.01).
Conclusions: Unsuccessful first-line short-course therapy did not compromise retreatment with sofosbuvir/ledipasvir/ribavirin (100% SVR12). SVR12 rates were significantly increased when ultrashort treatment varied between 4-7 weeks rather than 4-6 weeks. Ribavirin significantly reduced resistance emergence in those failing first-line therapy
Domestication of Campylobacter jejuni NCTC 11168
Reference and type strains of well-known bacteria have been a cornerstone of microbiology research for decades. The sharing of well-characterized isolates among laboratories has run in parallel with research efforts and enhanced the reproducibility of experiments, leading to a wealth of knowledge about trait variation in different species and the underlying genetics. Campylobacter jejuni strain NCTC 11168, deposited at the National Collection of Type Cultures in 1977, has been adopted widely as a reference strain by researchers worldwide and was the first Campylobacter for which the complete genome was published (in 2000). In this study, we collected 23 C . jejuni NCTC 11168 reference isolates from laboratories across the UK and compared variation in simple laboratory phenotypes with genetic variation in sequenced genomes. Putatively identical isolates, identified previously to have aberrant phenotypes, varied by up to 281 SNPs (in 15 genes) compared to the most recent reference strain. Isolates also display considerable phenotype variation in motility, morphology, growth at 37â°C, invasion of chicken and human cell lines, and susceptibility to ampicillin. This study provides evidence of ongoing evolutionary change among C. jejuni isolates as they are cultured in different laboratories and highlights the need for careful consideration of genetic variation within laboratory reference strains. This article contains data hosted by Microreact
- âŠ