1,817 research outputs found
Off-shoring, specialization and R&D
This paper investigates whether off-shoring promotes technological specialization by reallocating resources towards high-tech industries and/or stimulating within industry R&D. Using data for the US, Japan and Europe, our results show that material off-shoring promotes high-tech specialization through input reallocation between sectors, while service off-shoring favours technologically advanced production by increasing within-industry productivity, mainly via its positive impact on R&D. Conversely, we find that the increasing fragmentation of core production tasks, captured by narrow off-shoring, has adverse effects on technological specialisation, which suggests that this type of off-shoring is mainly pursued for cost-reduction motives
Offshoring and specialisation: are industries moving?
This paper investigates the impact of off-shoring on specialisation via its effect on national endowments and productivity. We use different definition of off-shoring to properly capture international fragmentation of production, while controlling for countries‟ stocks of R&D and ICT capital. Using industry data for the US, Japan and Europe we show that while off-shoring of materials can benefit a wide range of industries, service and intra-industry off-shoring can decrease specialisation in high-tech industry, both within manufacturing and services. This effect can be compensated with increasing R&D investments
We see ICT spillovers everywhere but in the econometric evidence: a reassessment
Using company-level data for the US we study the productivity effects of knowledge spillovers, induced by the diffusion of ICT in the markets where companies operate. We adopt multiple spillover proxies and account for firms' absorptive capacity and lagged effects. Our results show that intra-industry ICT spillovers have a contemporaneous negative effect while the impact of inter-industry spillovers is positive. The overall productivity effect of ICT is negative, except for those companies with a strong absorptive capacity. However, after a 5-year lag the overall spillover effect turns positive while the role of absorptive capacity diminishes as a consequence of decreasing learning costs and more accessible technology
The pulsar synchrotron: coherent radio emission
We propose a simple physical picture for the generation of coherent radio
emission in the axisymmetric pulsar magnetosphere that is quite different from
the canonical paradigm of radio emission coming from the magnetic polar caps.
In this first paper we consider only the axisymmetric case of an aligned
rotator. Our picture capitalizes on an important element of the MHD
representation of the magnetosphere, namely the separatrix between the
corotating closed-line region (the `dead zone') and the open field lines that
originate in the polar caps. Along the separatrix flows the return current that
corresponds to the main magnetospheric electric current emanating from the
polar caps. Across the separatrix, both the toroidal and poloidal components of
the magnetic field change discontinuously. The poloidal component discontinuity
requires the presence of a significant annular electric current which has up to
now been unaccounted for. We estimate the position and thickness of this
annular current at the tip of the closed line region, and show that it consists
of electrons (positrons) corotating with Lorentz factors on the order of 10^5,
emitting incoherent synchrotron radiation that peaks in the hard X-rays. These
particles stay in the region of highest annular current close to the equator
for a path-length of the order of one meter. We propose that, at wavelengths
comparable to that path-length, the particles emit coherent radiation, with
radiated power proportional to N^2, where N is the population of particles in
the above path-length. We calculate the total radio power in this wavelength
regime and its scaling with pulsar period and stellar magnetic field and show
that it is consistent with estimates of radio luminosity based on observations.Comment: Monthly Notices Letters, in pres
Observation and theoretical description of the pure Fano-effect in the valence-band photo-emission of ferromagnets
The pure Fano-effect in angle-integrated valence-band photo-emission of
ferromagnets has been observed for the first time. A contribution of the
intrinsic spin polarization to the spin polarization of the photo-electrons has
been avoided by an appropriate choice of the experimental parameters. The
theoretical description of the resulting spectra reveals a complete analogy to
the Fano-effect observed before for paramagnetic transition metals. While the
theoretical photo-current and spin difference spectra are found in good
quantitative agreement with experiment in the case of Fe and Co only a
qualitative agreement could be achieved in the case of Ni by calculations on
the basis of plain local spin density approximation (LSDA). Agreement with
experimental data could be improved in this case in a very substantial way by a
treatment of correlation effects on the basis of dynamical mean field theory
(DMFT).Comment: 11 pages, 3 figures accepted by PR
We see ICT spillovers everywhere but in the econometric evidence: a reassessment
Using company-level data for the US we study the productivity effects of knowledge spillovers, induced by the diffusion of ICT in the markets where companies operate. We adopt multiple spillover proxies and account for firms' absorptive capacity and lagged effects. Our results show that intra-industry ICT spillovers have a contemporaneous negative effect while the impact of inter-industry spillovers is positive. The overall productivity effect of ICT is negative, except for those companies with a strong absorptive capacity. However, after a 5-year lag the overall spillover effect turns positive while the role of absorptive capacity diminishes as a consequence of decreasing learning costs and more accessible technology
Atomistic long-term simulation of heat and mass transport
We formulate a theory of non-equilibrium statistical thermodynamics for ensembles of atoms or molecules. The theory is an application of Jayne's maximum entropy principle, which allows the statistical treatment of systems away from equilibrium. In particular, neither temperature nor atomic fractions are required to be uniform but instead are allowed to take different values from particle to particle. In addition, following the Coleman-Noll method of continuum thermodynamics we derive a dissipation inequality expressed in terms of discrete thermodynamic fluxes and forces. This discrete dissipation inequality effectively sets the structure for discrete kinetic potentials that couple the microscopic field rates to the corresponding driving forces, thus resulting in a closed set of equations governing the evolution of the system. We complement the general theory with a variational meanfield theory that provides a basis for the formulation of computationally tractable approximations. We present several validation cases, concerned with equilibrium properties of alloys, heat conduction in silicon nanowires and hydrogen desorption from palladium thin films, that demonstrate the range and scope of the method and assess its fidelity and predictiveness. These validation cases are characterized by the need or desirability to account for atomic-level properties while simultaneously entailing time scales much longer than those accessible to direct molecular dynamics. The ability of simple meanfield models and discrete kinetic laws to reproduce equilibrium properties and long-term behavior of complex systems is remarkable
The Tuning System for the HIE-ISOLDE High-Beta Quarter Wave Resonator
A new linac using superconducting quarter-wave resonators (QWR) is under
construction at CERN in the framework of the HIE-ISOLDE project. The QWRs are
made of niobium sputtered on a bulk copper substrate. The working frequency at
4.5 K is 101.28 MHz and they will provide 6 MV/m accelerating gradient on the
beam axis with a total maximum power dissipation of 10 W on cavity walls. A
tuning system is required in order to both minimize the forward power variation
in beam operation and to compensate the unavoidable uncertainties in the
frequency shift during the cool-down process. The tuning system has to fulfil a
complex combination of RF, structural and thermal requirements. The paper
presents the functional specifications and details the tuning system RF and
mechanical design and simulations. The results of the tests performed on a
prototype system are discussed and the industrialization strategy is presented
in view of final production.Comment: 5 pages, The 16th International Conference on RF Superconductivity
(SRF2013), Paris, France, Sep 23-27, 201
Thermomagnetic history effects in SmMnGe
The intermetallic compound SmMnGe, displaying multiple magnetic phase
transitions, is being investigated in detail for its magnetization behavior
near the 145 K first order ferromagnetic to antiferromagnetic transition
occuring on cooling, in particular for thermomagnetic history effects in the
magnetization data. The most unusual finding is that the thermomagnetic
irreversibility, [= M(T)-M(T)] at 135 K is higher in
intermediate magnetic field strengths. By studying the response of the sample
(i.e., thermomagnetic irreversibility and thermal hysteresis) to different
histories of application of magnetic field and temperature, we demonstrate how
the supercooling and superheating of the metastable magnetic phases across the
first order transition at 145 K contribute to overall thermomagnetic
irreversibility.Comment: 15 pages, 5 figures, to appear in Physical Review
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