4,624 research outputs found
The Swiss National Bank's monetary policy concept - an example of a 'principles-based' policy framework
The practice of monetary policy has evolved a great deal since the early 1990s. This evolution was significantly influenced by rapid developments in the theory of monetary policy. A new consensus about 'principles-based' monetary policy appears to be emerging. It marries a firm long-term anchor for nominal stability, rooted in the original ideas behind inflation targeting, with short-term flexibility, based on a more discretionary and pragmatic approach to monetary policy. The SNB's monetary policy framework - with a firm nominal anchor but with an emphasis on the need for flexibility - reflects, to a considerable degree, the emerging academic consensus about best-practice monetary policy. With its successful seven-year track record, it may serve as an interesting case study for a policy aiming at an intermediate position between full discretion and rigidly defined short-term inflation targeting.Swiss National Bank, monetary policy, inflation targeting, rules, discretion
Sources of productivity growth in the American coal industry
This paper develops new techniques to assess the expanse of the geographic market under varying supply and demand conditions and applies these techniques to the current wholesale electricity market in the western United States. This paper finds that, by and large, the expanse of the geographic market extends across most of the western United States, but that conditions which create congestion along transmission lines, such as high hydroelectric flows in the Pacific Northwest, transmission line outages and deratings, and high demand for wholesale electricity, cause the expanse of the geographic market to narrow at certain times.Supported by the MIT Center for Energy and Environmental Policy Research
Step size of the rotary proton motor in single FoF1-ATP synthase from a thermoalkaliphilic bacterium by DCO-ALEX FRET
Thermophilic enzymes can operate at higher temperatures but show reduced
activities at room temperature. They are in general more stable during
preparation and, accordingly, are considered to be more rigid in structure.
Crystallization is often easier compared to proteins from bacteria growing at
ambient temperatures, especially for membrane proteins. The ATP-producing
enzyme FoF1-ATP synthase from thermoalkaliphilic Caldalkalibacillus thermarum
strain TA2.A1 is driven by a Fo motor consisting of a ring of 13 c-subunits. We
applied a single-molecule F\"orster resonance energy transfer (FRET) approach
using duty cycle-optimized alternating laser excitation (DCO-ALEX) to monitor
the expected 13-stepped rotary Fo motor at work. New FRET transition histograms
were developed to identify the smaller step sizes compared to the 10-stepped Fo
motor of the Escherichia coli enzyme. Dwell time analysis revealed the
temperature and the LDAO dependence of the Fo motor activity on the single
molecule level. Back-and-forth stepping of the Fo motor occurs fast indicating
a high flexibility in the membrane part of this thermophilic enzyme.Comment: 14 pages, 7 figure
Microscopic approach to pion-nucleus dynamics
Elastic scattering of pions from finite nuclei is investigated utilizing a
contemporary, momentum--space first--order optical potential combined with
microscopic estimates of second--order corrections. The calculation of the
first--order potential includes:\ \ (1)~full Fermi--averaging integration
including both the delta propagation and the intrinsic nonlocalities in the
- amplitude, (2)~fully covariant kinematics, (3)~use of invariant
amplitudes which do not contain kinematic singularities, and (4)~a
finite--range off--shell pion--nucleon model which contains the nucleon pole
term. The effect of the delta--nucleus interaction is included via the mean
spectral--energy approximation. It is demonstrated that this produces a
convergent perturbation theory in which the Pauli corrections (here treated as
a second--order term) cancel remarkably against the pion true absorption terms.
Parameter--free results, including the delta--nucleus shell--model potential,
Pauli corrections, pion true absorption, and short--range correlations are
presented. (2 figures available from authors)Comment: 13 page
Chinese crisis communication in the early stage of the COVID-19 pandemic: a discourse analysis of 'People's Daily' news articles in response to threatening international news coverage
This paper examines China's international communication strategy during the initial phase of the global COVID-19 pandemic. In the spring of 2020, Western governments and media began criticising the systematic lack of transparency and accountability in the Chinese political system in relation to the failed containment of the Wuhan outbreak. Facing an unprecedented reputational crisis, the Chinese Communist Party (CCP) mobilised its foreign-language media in an attempt to influence the international discourse on COVID-19. Surveying the English and Chinese editions of the People's Daily, this study identifies CCP discourses aimed at foreign audiences and traces their evolution during the early stages of the pandemic. Overall, the study provides a comprehensive map of Chinese narratives on COVID-19 and generates fresh insights into CCP crisis communication
Designing a virtual cockpit for helicopter offshore operations
In recent years the number of offshore wind farms is rapidly increasing. Especially coastal European countries are building numerous offshore wind turbines in the Baltic, the North, and the Irish Sea. During both construction and operation of these wind farms, many specially-equipped helicopters are on duty. Due to their flexibility, their hover capability, and their higher speed compared to ships, these aircraft perform important tasks like helicopter emergency medical services (HEMS) as well as passenger and freight transfer flights. The missions often include specific challenges like ship landings or hoist operations to drop off workers onto wind turbines.
However, adverse weather conditions frequently limit offshore helicopter operations. In such scenarios, the adoption of aircraft-mounted sensors and obstacle databases together with helmet-mounted displays (HMD) seems to offer great potential to improve the operational capabilities of the helicopters used. By displaying environmental information in a visual conformal manner, these systems mitigate the loss of visual reference to the environment. This helps the pilots to maintain proper situational awareness (SA).
This paper presents how our previously introduced concept of an HMD-based virtual flight deck can enhance offshore helicopter missions. The advantages of this system – for instance its “see-through the airframe”-capability and its highly-flexible cockpit instrument setup – enable us to design entirely novel pilot assistance systems. The work analyzes the specific requirements on our virtual cockpit so as to assist the helicopter crew in offshore-specific tasks. The gained knowledge is used to propose and evaluate concepts for a virtual cockpit that is tailor-made for helicopter offshore maneuvers
Disorder scattering in classical flat channel transport of particles between twisted magnetic square patterns
We measure the trajectories of macroscopic magnetic particles pulled against
gravity between twisted alternating magnetic square patterns in a superposed
homogeneous magnetic field normal to both patterns. The two patterns are built
from a set of magentic cubes having a distribution of magnetization. The
magnetic potential between the patterns is a sum of three contributions: two
being periodic on two lattices with different magnitude and orientation, and
the third random contribution arising from the distribution of magnetization of
the cubes. As one varies the twist angle between the two patterns each time the
twist angle coincides with a magic twist angle one of the two periodic lattices
becomes a sublattice of the other lattice. Simulations of particles moving
through patterns with a precise cube magnetization produce pronounced mobility
peaks near magic twist angles that are associated with flat channels. Weak
random fluctuations of the cube magnetization in the experiment and the
simulations cause enhanced random disorder of the potential and reduce the
mobility by scattering particles into the interior of the twisted Wigner Seitz
cells. The mobility undergoes an Anderson transition from magic to generic
behavior as the magnetization disorder increases beyond half of a percent of
the cube magnetization
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