3,960 research outputs found
The macroeconomic effects of a pandemic in Europe - A model-based assessment
This report estimates possible macroeconomic effects of a pandemic taking place in the EU in 2006, using a quarterly macroeconomic model. The macroeconomic costs of a pandemic, that is the cost in terms of production lost due to illness and death measured as reductions in GDP growth and/or declines in the level of GDP, are quantified in various pandemic scenarios. We focus on two sectors of the European economy that are expected to be particularly severely hit, tourism and trade. The results are compared with those obtained in similar studies. Our basic conclusion is that, although a pandemic would take a huge toll in human suffering, it would most likely not be a severe threat to the European macroeconomy.Pandemics, avian flu, Spanish influenza, macroeconomic model, Jonung, Roeger
Knowledge Transfer in Buyer-Supplier Relationships – When It (Not) Occurs
Abuyer’s technical knowledge may increase the efficiency of its supplier.Suppliers, however, frequently maintain relationships with additional buyers. Knowledge disclosure then bears the risk of benefiting one’s own competitor due to opportunistic knowledge transmission through the common supplier. We show that in one-shot relationships no knowledge disclosure takes place because the supplier has an incentive for knowledge transmission and, in anticipation of this outcome, buyers refuse to disclose any of their knowledge. In repeated relationships knowledge disclosure is stabilized by larger technological proximity between buyers and suppliers and destabilized by the absolute value of the knowledge.Knowledge Transfer, Knowledge Spillovers, Cooperation, Innovation, Repeated Games
Non-LTE Spectral Analysis of Extremely Hot Post-AGB Stars: Constraints for Evolutionary Theory
Spectral analysis by means of Non-LTE model-atmosphere techniques has arrived
at a high level of sophistication: fully line-blanketed model atmospheres which
consider opacities of all elements from H to Ni allow the reliable
determination of photospheric parameters of hot, compact stars. Such models
provide a crucial test of stellar evolutionary theory: recent abundance
determinations of trace elements like, e.g., F, Ne, Mg, P, S, Ar, Fe, and Ni
are suited to investigate on AGB nucleosynthesis. E.g., the strong Fe depletion
found in hydrogen-deficient post-AGB stars is a clear indication of an
efficient s-process on the AGB where Fe is transformed into Ni or even heavier
trans iron-group elements. We present results of recent spectral analyses based
on high-resolution UV observations of hot stars.Comment: 6 pages, 2 figure
Uncertainty Relations for Angular Momentum
In this work we study various notions of uncertainty for angular momentum in
the spin-s representation of SU(2). We characterize the "uncertainty regions''
given by all vectors, whose components are specified by the variances of the
three angular momentum components. A basic feature of this set is a lower bound
for the sum of the three variances. We give a method for obtaining optimal
lower bounds for uncertainty regions for general operator triples, and evaluate
these for small s. Further lower bounds are derived by generalizing the
technique by which Robertson obtained his state-dependent lower bound. These
are optimal for large s, since they are saturated by states taken from the
Holstein-Primakoff approximation. We show that, for all s, all variances are
consistent with the so-called vector model, i.e., they can also be realized by
a classical probability measure on a sphere of radius sqrt(s(s+1)). Entropic
uncertainty relations can be discussed similarly, but are minimized by
different states than those minimizing the variances for small s. For large s
the Maassen-Uffink bound becomes sharp and we explicitly describe the
extremalizing states. Measurement uncertainty, as recently discussed by Busch,
Lahti and Werner for position and momentum, is introduced and a generalized
observable (POVM) which minimizes the worst case measurement uncertainty of all
angular momentum components is explicitly determined, along with the minimal
uncertainty. The output vectors for the optimal measurement all have the same
length r(s), where r(s)/s goes to 1 as s tends to infinity.Comment: 30 pages, 22 figures, 1 cut-out paper model, video abstract available
on https://youtu.be/h01pHekcwF
Accessing topological superconductivity via a combined STM and renormalization group analysis
The search for topological superconductors has recently become a key issue in
condensed matter physics, because of their possible relevance to provide a
platform for Majorana bound states, non-Abelian statistics, and fault-tolerant
quantum computing. We propose a new scheme which links as directly as possible
the experimental search to a material-based microscopic theory for topological
superconductivity. For this, the analysis of scanning tunneling microscopy,
which typically uses a phenomenological ansatz for the superconductor gap
functions, is elevated to a theory, where a multi-orbital functional
renormalization group analysis allows for an unbiased microscopic determination
of the material-dependent pairing potentials. The combined approach is
highlighted for paradigmatic hexagonal systems, such as doped graphene and
water-intercalated sodium cobaltates, where lattice symmetry and electronic
correlations yield a propensity for a chiral singlet topological superconductor
state. We demonstrate that our microscopic material-oriented procedure is
necessary to uniquely resolve a topological superconductor state.Comment: phenomenological STM predictions and temperature dependence of
conductance as well as references added (28 pages, 8 figures
Knowledge Transfer in Buyer-Supplier Relationships - When It (Not) Occurs
Abuyer?s technical knowledge may increase the efficiency of its supplier. Suppliers, however, frequently maintain relationships with additional buyers. Knowledge disclosure then bears the risk of benefiting one?s own competitor due to opportunistic knowledge transmission through the common supplier. We show that in one-shot relationships no knowledge disclosure takes place because the supplier has an incentive for knowledge transmission and, in anticipation of this outcome, buyers refuse to disclose any of their knowledge. In repeated relationships knowledge disclosure is stabilized by larger technological proximity between buyers and suppliers and destabilized by the absolute value of the knowledge
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Reduction of Activated Alkenes by PIII/PV Redox Cycling Catalysis
The carbon–carbon double bond of unsaturated carbonyl compounds was readily reduced by using a phosphetane oxide catalyst in the presence of a simple organosilane as the terminal reductant and water as the hydrogen source. Quantitative hydrogenation was observed when 1.0 mol % of a methyl-substituted phosphetane oxide was employed as the catalyst. The procedure is highly selective towards activated double bonds, tolerating a variety of functional groups that are usually prone to reduction. In total, 25 alkenes and two alkynes were hydrogenated to the corresponding alkanes in excellent yields of up to 99 %. Notably, less active poly(methylhydrosiloxane) could also be utilized as the terminal reductant. Mechanistic investigations revealed the phosphane as the catalyst resting state and a protonation/deprotonation sequence as the crucial step in the catalytic cycle. © 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA
Smart-phone assisted travel assistance for passengers with reduced mobility
Public transportation is a main factor for a reliable mobility in urban and rural areas. Every user group and
their specific requirements have to be considered during planning and realization of public transportation services. Hence public transport operators have to ensure a barrier-free public transportation service. Certainly this barrier-freeness still is not realized for every user group, due to the high complexity of public transportation systems. This article outlines an individual travel assistance application for smart phones which can be easily integrated into existing background systems of public transport operators
Why powerful buyers finance suppliers' R&D
It is a common concern that pricing pressure by powerful buyers discourages suppliers' R&D investments. Employing a simple monopsonist - competitive upstream industry - framework, this paper qualifies this view in two respects. First, the monopsonist has an incentive to subsidize upstream R&D which yields more upstream R&D and higher profits in both industries than the monopsonist's commitment to higher prices. Secondly, in the presence of intra-industry R&D spillovers between upstream firms, the monopsonist has an even stronger incentive to finance upstream R&D. If the monopsonist finances more than fifty percent of suppliers R&D efforts, R&D investments in upstream industry will be higher than in the case of buyer competition
Preparing for retirement - a comparative view : personal experiences of financial preparations from four nations
No abstract availabl
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