21,109 research outputs found
Leadership: The Tabletop Concept
Applying the analogy of the four supporting pillars of support for a table — and thus, in similar fashion with a true and lasting, moral leader — Hagelberg discusses how four leadership principles in particular – integrity, competence, emotional intelligence, and vision – are the four essential traits of successful and lasting leadership
Spin ice on the trillium lattice studied by Monte Carlo calculations
We study a local ferromagnetic Ising model for classical spins on the
trillium lattice. The ground state of this model features two spins out(/in)
and one spin in(/out) on each triangle, and leads to a macroscopic ground state
degeneracy. Our Monte Carlo simulations find a ground state entropy
intermediate to that of spin ice on the kagome and pyrochlore lattices,
suggesting that trillium spin ice is highly frustrated. To motivate the search
for trillium spin ice, we calculate the magnetic susceptibility and structure
factor. We note the qualitative resemblance of the susceptibility to previously
published work on EuPtSi, which features local moments on the trillium lattice.Comment: 8 pages, 6 figure
Satellite appendage tie down cord Patent
Design and construction of satellite appendage tie-down cor
Localization and centrality in networks
Eigenvector centrality is a common measure of the importance of nodes in a
network. Here we show that under common conditions the eigenvector centrality
displays a localization transition that causes most of the weight of the
centrality to concentrate on a small number of nodes in the network. In this
regime the measure is no longer useful for distinguishing among the remaining
nodes and its efficacy as a network metric is impaired. As a remedy, we propose
an alternative centrality measure based on the nonbacktracking matrix, which
gives results closely similar to the standard eigenvector centrality in dense
networks where the latter is well behaved, but avoids localization and gives
useful results in regimes where the standard centrality fails.Comment: 5 pages, 1 figur
Diagonal Slice Four-Wave Mixing: Natural Separation of Coherent Broadening Mechanisms
We present an ultrafast coherent spectroscopy data acquisition scheme that
samples slices of the time domain used in multidimensional coherent
spectroscopy to achieve faster data collection than full spectra. We derive
analytical expressions for resonance lineshapes using this technique that
completely separate homogeneous and inhomogeneous broadening contributions into
separate projected lineshapes for arbitrary inhomogeneous broadening. These
lineshape expressions are also valid for slices taken from full
multidimensional spectra and allow direct measurement of the parameters
contributing to the lineshapes in those spectra as well as our own
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Understanding Behavioral Responses of Wildlife to Traffic to Improve Mitigation Planning
Creating and maintaining sustainable transportation systems depends in part on understanding and mitigating ecological impacts. Wildlife crossing structures (WCS) are often used to mitigate impacts on wildlife populations. WCS and existing structures may provide passage for multiple species, depending on their sensitivity to traffic disturbance and perception of the roadway. In a previous project, the research team found that traffic conditions and traffic noise could reduce WCS effectiveness in facilitating passage of diverse and sensitive species. In the current project, they expanded the geographic scope to 26 sites throughout California, including detailed measurements of vehicle noise and lighting impacts on wildlife use of structures. They investigated individual animal behavior as the animals approached structures as a possible mechanism for reducing species diversity due to traffic disturbance. In order to inform future WCS planning, placement and construction, the team studied traffic noise and light impacts on wildlife in the vicinity of the proposed Liberty Canyon wildlife over-crossing (over US 101), the first and largest of its kind in California. They improved a preliminary statistical model of the effects of traffic on WCS use of existing structures. The authors recommend strategies for transportation agencies to use in developing and modifying WCS to improve wildlife passage.View the NCST Project Webpag
No evidence for oncogenic mutations in guanine nucleotide-binding proteins of human adrenocortical neoplasms
G-Proteins are membrane-bound heterotrimeric polypeptides that couple receptor signals to second messenger systems such as cAMP. Recently, point mutations at 2 codons of the highly preserved alpha-chain of Gs, the adenyl cyclase-stimulating G-protein, were found in GH-secreting pituitary tumors. These mutations resulted in constitutively activated Gs alpha and high intracellular cAMP levels. In addition, point mutations at similar codons of a different G-protein, G(i) alpha 2, were reported in adrenocortical neoplasms, suggesting a potential role of this isoform in the genesis of these tumors. We reevaluated the frequency of constitutively activating point mutations in the alpha- chain of the stimulatory (Gs alpha) and inhibitory (G(i) alpha 2) G- proteins in human adrenocortical tumors. Seven adrenocortical carcinomas, 2 human adrenocortical tumor cell lines, and 11 adrenocortical adenomas were studied. Genomic DNA was purified from either frozen tumor tissue or paraffin-embedded sections. Using specific primers and the polymerase chain reaction, DNA fragments surrounding codons 201 and 227 (Gs alpha) and 179 and 205 (G(i) alpha 2) were amplified and visualized on a 2% agarose gel. In a second asymmetric polymerase chain reaction, using nested primers, single stranded DNA was generated using 1-10 microL of the initial amplification mixture and directly sequenced using the dideoxy chain termination method of Sanger. We found no mutations at codons 201, 227 and 179, 205 of Gs alpha and G(i) alpha 2, respectively, in the tumors studied. We conclude that previously identified oncogenic point mutations in the stimulatory and inhibitory alpha-chain of G-proteins do not appear to be present at high frequency in adrenal neoplasms. Thus, the mechanism(s) of tumorigenesis in these tumors is different from that in GH-secreting adenomas and may involve oncogenic mutations of other cell constituents
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