247 research outputs found
An Empirical Investigation of the Predictors of Executive Career Success
The present study examined the degree to which demographic, human capital,motivational, organizational, and industry/region variables predicted executive career success. Career success was assumed to comprise objective (pay, ascendancy) and subjective (job satisfaction, career satisfaction) elements. Results obtained from a sample of 1,388 U.S.executives suggested that demographic, human capital, motivational, and organizational variables explained significant variance in objective career success and in career satisfaction. Particularly interesting were findings that educational level, quality, prestige, and degree type all predicted financial success. In contrast, only the motivational and organizational variables explained significant amounts of variance in job satisfaction. These findings suggest that the variables that lead to objective career success often are quite different from those that lead to subjectively defined success
Synthesis and characterization of patterned surfaces and catalytically relevant binary nanocrystalline intermetallic compounds
As devices and new technologies continue to shrink, nanocrystalline multi-metal
compounds are becoming increasingly important for high efficiency and
multifunctionality. However, synthetic methods to make desirable nanocrystalline
multi-metallics are not yet matured. In response to this deficiency, we have developed
several solution-based methods to synthesize nanocrystalline binary alloy and
intermetallic compounds. This dissertation describes the processes we have developed,
as well as our investigations into the use of lithographically patterned surfaces for
template-directed self-assembly of solution dispersible colloids.
We used a modified polyol process to synthesize nanocrystalline intermetallics of
late transition and main-group metals in the M-Sn, Pt-M’, and Co-Sb systems. These
compounds are known to have interesting physical properties and as nanocrystalline
materials they may be useful for magnetic, thermoelectric, and catalytic applications.
While the polyol method is quite general, it is limited to metals that are somewhat easy
to reduce. Accordingly, we focused our synthetic efforts on intermetallics comprised of highly electropositive metals. We find that we can react single-metal nanoparticles with
zero-valent organometallic Zinc reagents in hot, coordinating amine solvents via a
thermal decomposition process to form several intermetallics in the M’’-Zn system.
Characterization of the single-metal intermediates and final intermetallic products shows
a general retention of morphology throughout the reaction, and changes in optical
properties are also observed. Following this principle of conversion chemistry, we can
employ the high reactivity of nanocrystals to reversibly convert between intermetallic
phases within the Pt-Sn system, where PtSn2 ↔ PtSn ↔ Pt3Sn. Our conversion
chemistry occurs in solution at temperatures below 300 °C and within 1 hour,
highlighting the high reactivity of our nanocrystalline materials compared to the bulk.
Some evidence of the generality for this process is also presented.
Our nanocrystalline powders are dispersible in solution, and as such are
amenable to solution-based processing techniques developed for colloidal dispersions.
Accordingly, we have investigated the use of lithographically patterned surfaces to
control the self-assembly of colloidal particles. We find that we can rapidly crystallize
2-dimensional building blocks, as well as use epitaxial templates to direct the formation
of interesting superlattice structures comprised of a bidisperse population of particles
What’s Germany really thinking? Vince Cable, Simon Hix and Jeromin Zettelmeyer discuss Brexit
German economic policy advisor Jeromin Zettelmeyer (far left) joined the LSE’s Simon Hix (near left) and former UK business secretary Vince Cable on 7 September to discuss how Germany plans to negotiate Brexit. How much will Angela Merkel – herself under domestic pressure – be prepared to concede to keep the UK in the Single Market (assuming Britain wants to do so)? What does Germany want out of the final agreement? Robert van Geffen reports on the discussion
A co-crystal between benzene and ethane: a potential evaporite material for Saturn’s moon Titan
Using synchrotron X-ray powder diffraction, the structure of a co-crystal
between benzene and ethane formed in situ at cryogenic conditions has been
determined, and validated using dispersion-corrected density functional theory
calculations. The structure comprises a lattice of benzene molecules hosting
ethane molecules within channels. Similarity between the intermolecular
interactions found in the co-crystal and in pure benzene indicate that the C—
H network of benzene is maintained in the co-crystal, however, this expands
to accommodate the guest ethane molecules. The co-crystal has a 3:1
benzene:ethane stoichiometry and is described in the space group R3 with a =
15.977 (1) AËš and c = 5.581 (1) AËš at 90 K, with a density of 1.067 g cm3
. The
conditions under which this co-crystal forms identify it is a potential that forms
from evaporation of Saturn’s moon Titan’s lakes, an evaporite material
Quantum states of light produced by a high-gain optical parametric amplifier for use in quantum lithography
We present a theoretical analysis of the properties of an unseeded optical parametic amplifier (OPA) used as the source of entangled photons for applications in quantum lithography. We first study the dependence of the excitation rate of a two-photon absorber on the intensity of the light leaving the OPA. We find that the rate depends linearly on intensity only for output beams so weak that they contain fewer than one photon per mode. We also study the use of an N-photon absorber for arbitrary N as the recording medium to be used with such a light source. We find that the contrast of the interference pattern and the sharpness of the fringe maxima tend to increase with increasing values of N, but that the density of fringes and thus the limiting resolution does not increase with N. We conclude that the output of an unseeded OPA exciting an N-photon absorber provides an attractive system in which to perform quantum lithography
A nonmitochondrial hydrogen production in Naegleria gruberi
Naegleria gruberi is a free-living heterotrophic aerobic amoeba well known for its ability to transform from an amoeba to a flagellate form. The genome of N. gruberi has been recently published, and in silico predictions demonstrated that Naegleria has the capacity for both aerobic respiration and anaerobic biochemistry to produce molecular hydrogen in its mitochondria. This finding was considered to have fundamental implications on the evolution of mitochondrial metabolism and of the last eukaryotic common ancestor. However, no actual experimental data have been shown to support this hypothesis. For this reason, we have decided to investigate the anaerobic metabolism of the mitochondrion of N. gruberi. Using in vivo biochemical assays, we have demonstrated that N. gruberi has indeed a functional [FeFe]-hydrogenase, an enzyme that is attributed to anaerobic organisms. Surprisingly, in contrast to the published predictions, we have demonstrated that hydrogenase is localized exclusively in the cytosol, while no hydrogenase activity was associated with mitochondria of the organism. In addition, cytosolic localization displayed for HydE, a marker component of hydrogenase maturases. Naegleria gruberi, an obligate aerobic organism and one of the earliest eukaryotes, is producing hydrogen, a function that raises questions on the purpose of this pathway for the lifestyle of the organism and potentially on the evolution of eukaryotes
- …