4,449 research outputs found
Probing Light Atoms at Sub-nanometer Resolution: Realization of Scanning Transmission Electron Microscope Holography
Atomic resolution imaging in transmission electron microscopy (TEM) and
scanning TEM (STEM) of light elements in electron-transparent materials has
long been a challenge. Biomolecular materials, for example, are rapidly altered
when illuminated with electrons. These issues have driven the development of
TEM and STEM techniques that enable the structural analysis of electron
beam-sensitive and weakly scattering nano-materials. Here, we demonstrate such
a technique, STEM holography, capable of absolute phase and amplitude object
wave measurement with respect to a vacuum reference wave. We use an
amplitude-dividing nanofabricated grating to prepare multiple spatially
separated electron diffraction probe beams focused at the sample plane, such
that one beam transmits through the specimen while the others pass through
vacuum. We raster-scan the diffracted probes over the region of interest. We
configure the post specimen imaging system of the microscope to diffraction
mode, overlapping the probes to form an interference pattern at the detector.
Using a fast-readout, direct electron detector, we record and analyze the
interference fringes at each position in a 2D raster scan to reconstruct the
complex transfer function of the specimen, t(x). We apply this technique to
image a standard target specimen consisting of gold nanoparticles on a thin
amorphous carbon substrate, and demonstrate 2.4 angstrom resolution phase
images. We find that STEM holography offers higher phase-contrast of the
amorphous material while maintaining Au atomic lattice resolution when compared
with high angle annular dark field STEM.Comment: 9 pages, 5 figures in main text, 1 supplemental figure in the
appendi
GDP Data Revisions and Forward-Looking Monetary Policy in Switzerland
This paper analyzes forward-looking rules for Swiss monetary policy in a small structural VAR model consisting of four variables taking into account data revisions for GDP. First, the paper develops an analytical method to analyze the effect of data revision errors in GDP on the ex ante or conditional inflation-output-growth volatility trade-off and applies it to Swiss data. Second, the effects of different targets in a forward-looking monetary policy on ex post or unconditional volatility of inflation and output growth is explored by a simulation exercise. In general, the results obtained suggest that focusing monetary policy on GDP growth instead on inflation may lead to an inefficient policy with both increased medium term inflation and GDP growth volatility in the presence of GDP data revisions.Structural VAR, forward-looking monetary policy, efficiency frontier, GDP data revisions
The Analysis of Forward-Looking Monetary Policy in a SVAR Framework
This paper analyzes forward-looking monetary policy rules in structural VARâs. First, an approach for modeling a monetary policy which aims at a strict medium term inflation or output growth target is developed. Second, the ex ante inflation-output-growth volatility trade-off for a forward-looking policy aiming at a convex combination these strategies is derived. Finally, an illustration of our approach using Swiss data is given.Structural VAR, forward-looking monetary policy, efficiency frontier
Measurement errors in GDP and forward-looking monetary policy: The Swiss case
This paper analyzes forward-looking rules for Swiss monetary policy in a small structural VAR consisting of four variables. First, the paper looks at the ex ante inflation-output-growth volatility trade-off for a forward-looking policy aiming at a convex combination of a strict inflation and output growth targeting rule implied by this SVAR model. Thereby the paper introduces a new analytical method. Second, the paper considers the effect of measurement errors in GDP on this inflation-output-growth volatility trade-off. Third, the paper works at the impact of changing beliefs about the potential growth rate on the variability of output growth and inflation. Finally the effects of different targets in a forward-looking monetary policy on ex post or unconditional volatility of inflation and output growth is explored by a simulation exercise. --Structural VAR,forward-looking monetary policy,efficiency frontier,GDP measurement errors
Symmetrical and asymmetrical outcomes of leader anger expression: a qualitative study of army personnel
Recent studies have highlighted the utility of anger at work, suggesting that anger can have positive outcomes. Using the Dual Threshold Model, we assess the positive and negative consequences of anger expressions at work and focus on the conditions under which expressions of anger crossing the impropriety threshold are perceived as productive or counterproductive by observers or targets of that anger. To explore this phenomenon, we conducted a phenomenological study (n = 20) to probe the lived experiences of followers (as observers and targets) associated with anger expressions by military leaders. The nature of task (e.g. the display rules prescribed for combat situations) emerged as one condition under which the crossing of the impropriety threshold leads to positive outcomes of anger expressions. Our data reveal tensions between emotional display rules and emotional display norms in the military, thereby fostering paradoxical attitudes toward anger expression and its consequences among followers. Within this paradoxical space, anger expressions have both positive (asymmetrical) and negative (symmetrical) consequences. We place our findings in the context of the Dual Threshold Model, discuss the practical implications of our research and offer avenues for future studies
Permian trilobites and the applicability of the âliving fossilâ concept to extinct clades
Some taxa occupy our imaginations as âliving fossilsâ because they were known from the fossil record before being discovered alive today. Other taxa are considered âliving fossilsâ because modern relatives bear a strong morphological resemblance to fossil relatives, or because they occupy a contracted geographic range or have less diversity now than in the past, or because they represent phylogenetic diversity that requires conservation. A characterizing feature of living fossilsâand thus an implicit assumption of all criteriaâis that the âliving fossilâ of interest is extant. However, the general research questions that âliving fossilsâ inspireâWhy do rates of evolution vary across organisms, across traits, and across time? Why do some clades decline in diversity over extended periods?âmay be applied to any clade, including completely extinct clades. We propose that there is nothing special about ânowâ when it comes to pursuing these questions and that it is unnecessarily limiting to restrict research programs to clades for which an extant member meets some conception of the âliving fossilâ moniker. To this end, we investigate the extent to which Permian trilobites might resemble âliving fossils,â albeit from the perspective of 253 million years ago, when the last trilobites were still alive. We do so by comparing the taxonomic diversity, geographic range, and morphological disparity of trilobites living in the Permian to earlier time periods. We find that Permian trilobites meet most definitions of living fossils, although our assessment of morphological change and character retention depend on taxonomic scale
The case for emotional intelligence in organizational research
Since its popularization by Goleman (1995), the concept of emotional intelligence has been the subject of ongoing controversy, so it is understandable that the model we proposed, which includes emotional intelligence as a moderator variable, would attract its share of criticism
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