91 research outputs found
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Better insurance could effectively mitigate the increase in economic growth losses from U.S. hurricanes under global warming
Global warming is likely to increase the proportion of intense hurricanes in the North Atlantic. Here, we analyze how this may affect economic growth. To this end, we introduce an event-based macroeconomic growth model that temporally resolves how growth depends on the heterogeneity of hurricane shocks. For the United States, we find that economic growth losses scale superlinearly with shock heterogeneity. We explain this by a disproportional increase of indirect losses with the magnitude of direct damage, which can lead to an incomplete recovery of the economy between consecutive intense landfall events. On the basis of two different methods to estimate the future frequency increase of intense hurricanes, we project annual growth losses to increase between 10 and 146% in a 2°C world compared to the period 1980–2014. Our modeling suggests that higher insurance coverage can compensate for this climate change–induced increase in growth losses
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Post-Brexit no-trade-deal scenario: Short-term consumer benefit at the expense of long-term economic development
After the United Kingdom has left the European Union it remains unclear whether the two parties can successfully negotiate and sign a trade agreement within the transition period. Ongoing negotiations, practical obstacles and resulting uncertainties make it highly unlikely that economic actors would be fully prepared to a “no-trade-deal” situation. Here we provide an economic shock simulation of the immediate aftermath of such a post-Brexit no-trade-deal scenario by computing the time evolution of more than 1.8 million interactions between more than 6,600 economic actors in the global trade network. We find an abrupt decline in the number of goods produced in the UK and the EU. This sudden output reduction is caused by drops in demand as customers on the respective other side of the Channel incorporate the new trade restriction into their decision-making. As a response, producers reduce prices in order to stimulate demand elsewhere. In the short term consumers benefit from lower prices but production value decreases with potentially severe socio-economic consequences in the longer term
Future heat stress to reduce people’s purchasing power
With increasing carbon emissions rising temperatures are likely to impact our economies and societies profoundly. In particular, it has been shown that heat stress can strongly reduce labor productivity. The resulting economic perturbations can propagate along the global supply network. Here we show, using numerical simulations, that output losses due to heat stress alone are expected to increase by about 24% within the next 20 years, if no additional adaptation measures are taken. The subsequent market response with rising prices and supply shortages strongly reduces the consumers’ purchasing power in almost all countries including the US and Europe with particularly strong effects in India, Brazil, and Indonesia. As a consequence, the producing sectors in many regions temporarily benefit from higher selling prices while decreasing their production in quantity, whereas other countries suffer losses within their entire national economy. Our results stress that, even though climate shocks may stimulate economic activity in some regions and some sectors, their unpredictability exerts increasing pressure on people’s livelihood
Earth system modeling with endogenous and dynamic human societies: the copan:CORE open World-Earth modeling framework
Analysis of Earth system dynamics in the Anthropocene requires to explicitly
take into account the increasing magnitude of processes operating in human
societies, their cultures, economies and technosphere and their growing
feedback entanglement with those in the physical, chemical and biological
systems of the planet. However, current state-of-the-art Earth System Models do
not represent dynamic human societies and their feedback interactions with the
biogeophysical Earth system and macroeconomic Integrated Assessment Models
typically do so only with limited scope. This paper (i) proposes design
principles for constructing World-Earth Models (WEM) for Earth system analysis
of the Anthropocene, i.e., models of social (World) - ecological (Earth)
co-evolution on up to planetary scales, and (ii) presents the copan:CORE open
simulation modeling framework for developing, composing and analyzing such WEMs
based on the proposed principles. The framework provides a modular structure to
flexibly construct and study WEMs. These can contain biophysical (e.g. carbon
cycle dynamics), socio-metabolic/economic (e.g. economic growth) and
socio-cultural processes (e.g. voting on climate policies or changing social
norms) and their feedback interactions, and are based on elementary entity
types, e.g., grid cells and social systems. Thereby, copan:CORE enables the
epistemic flexibility needed for contributions towards Earth system analysis of
the Anthropocene given the large diversity of competing theories and
methodologies used for describing socio-metabolic/economic and socio-cultural
processes in the Earth system by various fields and schools of thought. To
illustrate the capabilities of the framework, we present an exemplary and
highly stylized WEM implemented in copan:CORE that illustrates how endogenizing
socio-cultural processes and feedbacks could fundamentally change macroscopic
model outcomes
Shunting operations at flat yards : retrieving freight railcars from storage tracks
In this paper, we study the railcar retrieval problem (RRT) where specified numbers of certain types of railcars have to be withdrawn from the storage tracks of a flat yard. This task arises in the daily operations of workshop yards for railcar maintenance. The objective is to minimize the total cost of shunting via methods such as minimizing the usage of shunting engines.
We describe the RRT formally, present a mixed-integer program formulation, and prove the general case to be NP-hard. For some special cases, exact algorithms with polynomial runtimes are proposed. We also analyze several intuitive heuristic solution approaches motivated by observed real-world planning routines. We evaluate their average performances in simulations with different scenarios and provide their worst-case performance guarantee. We show that although the analyzed heuristics result in much better solutions than the naive planning approach, they are still on average 30%-50% from the optimal objective value and may result in up to 14 times higher costs in the worst case. Therefore, we conclude that optimization should be implemented in practice in order to save valuable resources. Furthermore, we analyze the impacts of yard layout and the widespread organizational routine of presorting on the railcar retrieval cost
Origin and Properties of the Gap in the Half-Ferromagnetic Heusler Alloys
We study the origin of the gap and the role of chemical composition in the
half-ferromagnetic Heusler alloys using the full-potential screened KKR method.
In the paramagnetic phase the C1_b compounds, like NiMnSb, present a gap.
Systems with 18 valence electrons, Z_t, per unit cell, like CoTiSb, are
semiconductors, but when Z_t > 18 antibonding states are also populated, thus
the paramagnetic phase becomes unstable and the half-ferromagnetic one is
stabilized. The minority occupied bands accommodate a total of nine electrons
and the total magnetic moment per unit cell in mu_B is just the difference
between Z_t and . While the substitution of the transition metal
atoms may preserve the half-ferromagnetic character, substituting the atom
results in a practically rigid shift of the bands and the loss of
half-metallicity. Finally we show that expanding or contracting the lattice
parameter by 2% preserves the minority-spin gap.Comment: 11 pages, 7 figures New figures, revised tex
A Randomized Trial of Intravenous Alteplase before Endovascular Treatment for Stroke
The value of administering intravenous alteplase before endovascular treatment (EVT) for acute ischemic stroke has not been studied extensively, particularly in non-Asian populations. METHODS We performed an open-label, multicenter, randomized trial in Europe involving patients with stroke who presented directly to a hospital that was capable of providing EVT and who were eligible for intravenous alteplase and EVT. Patients were randomly assigned in a 1:1 ratio to receive EVT alone or intravenous alteplase followed by EVT (the standard of care). The primary end point was functional outcome on the modified Rankin scale (range, 0 [no disability] to 6 [death]) at 90 days. We assessed the superiority of EVT alone over alteplase plus EVT, as well as noninferiority by a margin of 0.8 for the lower boundary of the 95% confidence interval for the odds ratio of the two trial groups. Death from any cause and symptomatic intracerebral hemorrhage were the main safety end points. RESULTS The analysis included 539 patients. The median score on the modified Rankin scale at 90 days was 3 (interquartile range, 2 to 5) with EVT alone and 2 (interquartile range, 2 to 5) with alteplase plus EVT. The adjusted common odds ratio was 0.84 (95% confidence interval [CI], 0.62 to 1.15; P=0.28), which showed neither superiority nor noninferiority of EVT alone. Mortality was 20.5% with EVT alone and 15.8% with alteplase plus EVT (adjusted odds ratio, 1.39; 95% CI, 0.84 to 2.30). Symptomatic intracerebral hemorrhage occurred in 5.9% and 5.3% of the patients in the respective groups (adjusted odds ratio, 1.30; 95% CI, 0.60 to 2.81). CONCLUSIONS In a randomized trial involving European patients, EVT alone was neither superior nor noninferior to intravenous alteplase followed by EVT with regard to disability outcome at 90 days after stroke. The incidence of symptomatic intracerebral hemorrhage was similar in the two groups
Shunting operations at flat yards : Retrieving freight railcars from storage tracks
In this paper, we study the railcar retrieval problem (RRT) where a specified number of certain types of railcars has to be withdrawn from the storage tracks of a flat yard. This task arises in the daily operations of yards belonging to a workshop for railcar maintenance. The objective is to minimize the total costs of shunting, i.e. minimizing the usage of shunting engines.
We describe the RRT formally as a mixed-integer program and prove it to be NP-hard in the general case. In addition, we analyze several heuristics for solving the problem and provide their worst case performance guarantee. Furthermore, computational experiments are conducted that show the average performance of the introduced heuristics and compare them to the optimal solution provided by the mixedinteger program. The results show that both, the heuristics and the exact formulation come to solutions for realistically-sized instances in running times acceptable to practitioners, leading to the advice that optimization should be implemented in practice in order to save valuable
resources
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