562 research outputs found
Exploring barriers in expertise seeking : why don\u27t they ask an expert?
This paper reports findings from a research project that explores reasons why some employees prefer to seek expertise to resolve work-related problems from direct colleagues rather than designated internal experts. Several studies suggest that while an expert generally provides a higher quality solution in a shorter time, workers tend to ask friendly or proximate colleagues to help with knowledge-based problems at work. Prior research provides only fragmented insights into understanding the barriers to asking a designated internal expert for help at work. To address this gap, we asked post-graduate students enrolled in a knowledge management subject at a large Australian university to share their perspectives in an online discussion forum. Content analysis of the collected perspectives enabled identification of twenty-one factors that may limit the seeking of expertise from a designated internal expert. The factors are grouped in four categories: environment, accessibility, communication and personality. In addition one context variable is described, determining the extent to which the barriers are influential in a specific situation. By synthesising the results, we have proposed two models of expertise-seeking barriers. A literature review helps validate the barriers identified by the study. Key theoretical and practical implications are also discussed.<br /
Torsion cycles as non-local magnetic sources in non-orientable spaces
Non-orientable spaces can appear to carry net magnetic charge, even in the
absence of magnetic sources. It is shown that this effect can be understood as
a physical manifestation of the existence of torsion cycles of codimension one
in the homology of space.Comment: 17 pages, 4 figure
Effects of nanoparticles on murine macrophages
Metallic nanoparticles are more and more widely used in an increasing number
of applications. Consequently, they are more and more present in the
environment, and the risk that they may represent for human health must be
evaluated. This requires to increase our knowledge of the cellular responses to
nanoparticles. In this context, macrophages appear as an attractive system.
They play a major role in eliminating foreign matter, e.g. pathogens or
infectious agents, by phagocytosis and inflammatory responses, and are thus
highly likely to react to nanoparticles. We have decided to study their
responses to nanoparticles by a combination of classical and wide-scope
approaches such as proteomics. The long term goal of this study is the better
understanding of the responses of macrophages to nanoparticles, and thus to
help to assess their possible impact on human health. We chose as a model
system bone marrow-derived macrophages and studied the effect of commonly used
nanoparticles such as TiO2 and Cu. Classical responses of macrophage were
characterized and proteomic approaches based on 2D gels of whole cell extracts
were used. Preliminary proteomic data resulting from whole cell extracts showed
different effects for TiO2-NPs and Cu-NPs. Modifications of the expression of
several proteins involved in different pathways such as, for example, signal
transduction, endosome-lysosome pathway, Krebs cycle, oxidative stress response
have been underscored. These first results validate our proteomics approach and
open a new wide field of investigation for NPs impact on macrophagesComment: Nanosafe2010: International Conference on Safe Production and Use of
Nanomaterials 16-18 November 2010, Grenoble, France, Grenoble : France (2010
Molecular hydrogen in IllustrisTNG galaxies: Carefully comparing signatures of environment with local CO and SFR data
We examine how the post-processed content of molecular hydrogen (H2) in galaxies from the TNG100 cosmological, hydrodynamic simulation changes with environment at z = 0, assessing central/satellite status and host halo mass. We make close comparisons with the carbon monoxide (CO) emission survey xCOLD GASS where possible, having mock-observed TNG100 galaxies to match the survey's specifications. For a representative sample of host haloes across 1011 ≲ M200c/M· < 1014.6, TNG100 predicts that satellites with $m∗ ≥ 109, M⊙ should have a median deficit in their H2 fractions of ∼0.6 dex relative to centrals of the same stellar mass. Once observational and group-finding uncertainties are accounted for, the signature of this deficit decreases to ∼0.2 dex. Remarkably, we calculate a deficit in xCOLD GASS satellites' H2 content relative to centrals of 0.2-0.3 dex, in line with our prediction. We further show that TNG100 and SDSS data exhibit continuous declines in the average star formation rates of galaxies at fixed stellar mass in denser environments, in quantitative agreement with each other. By tracking satellites from their moment of infall in TNG100, we directly show that atomic hydrogen (H i) is depleted at fractionally higher rates than H2 on average. Supporting this picture, we find that the H2/H i mass ratios of satellites are elevated relative to centrals in xCOLD GASS. We provide additional predictions for the effect of environment on H2-both absolute and relative to H i-that can be tested with spectral stacking in future CO surveys
Micro-Raman Imaging of Isomeric Segregation in Small-Molecule Organic Semiconductors
Charge transport in organic semiconductors is highly sensitive to film heterogeneity and intermolecular interactions, but probing these properties on the length scales of disorder is often difficult. Here we use micro-Raman spectroscopy to assign vibrational modes of isomerically pure syn and anti 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (diF-TES ADT) by comparing to density functional theory calculations. With polarization-dependent measurements, we determine the orientation of crystallites in pure isomers. In mixed-isomer samples, we observe narrow linewidths and superposition spectra, indicating coexistence of isomerically pure sub-domains on length scales smaller than the probe area. Using the ring breathing modes close to 1300 cm−1 as indicators of the pure isomer crystalline sub-domains, we image their spatial distribution with 200-nm resolution. These results demonstrate the power of micro-Raman spectroscopy for investigating spatial heterogeneities and clarifying the origin of the reduced charge carrier mobility displayed in mixed-isomer diF-TES ADT
Low-Temperature Phase Transitions in a Soluble Oligoacene and Their Effect on Device Performance and Stability
The use of organic semiconductors in high-performance organic field-effect transistors requires a thorough understanding of the effects that processing conditions, thermal, and bias-stress history have on device operation. Here, we evaluate the temperature dependence of the electrical properties of transistors fabricated with 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene, a material that has attracted much attention recently due to its exceptional electrical properties. We have discovered a phase transition at T = 205 K and discuss its implications on device performance and stability. We examined the impact of this low-temperature phase transition on the thermodynamic, electrical, and structural properties of both single crystals and thin films of this material. Our results show that while the changes to the crystal structure are reversible, the induced thermal stress yields irreversible degradation of the devices
The Halo Mass of Optically Luminous Quasars at z ,F≈ ,F1-2 Measured via Gravitational Deflection of the Cosmic Microwave Background
© 2019. The American Astronomical Society. All rights reserved.We measure the average deflection of cosmic microwave background photons by quasars at 〈Z〉= 1.7. Our sample is selected from the Sloan Digital Sky Survey to cover the redshift range 0.9 ≤z≤2.2 with absolute i-band magnitudes of M i ≤-24 (K-corrected to z = 2). A stack of nearly 200,000 targets reveals an 8δ detection of Planck's estimate of the lensing convergence toward the quasars. We fit the signal with a model comprising a Navarro-Frenk-White density profile and a two-halo term accounting for correlated large-scale structure, which dominates the observed signal. The best-fitting model is described by an average halo mass log 10 (M h h -1 M)12.6 ±0.2 = and linear bias b=2.7±0.3 at 〈Z 〉= 1.7, in excellent agreement with clustering studies. We also report a hint, at a 90% confidence level, of a correlation between the convergence amplitude and luminosity, indicating that quasars brighter than Mi≲ -26 reside in halos of typical mass M h ≈ 10 13 h -1 M, scaling roughly as M h ∞ L opt 3/4 at M i ≲-24 mag, in good agreement with physically motivated quasar demography models. Although we acknowledge that this luminosity dependence is a marginal result, the observed Mh-L opt relationship could be interpreted as a reflection of the cutoff in the distribution of black hole accretion rates toward high Eddington ratios: the weak trend of Mh with Lopt observed at low luminosity becomes stronger for the most powerful quasars, which tend to be accreting close to the Eddington limit.Peer reviewedFinal Accepted Versio
Benefits of Empiric Nutritional and Medical Therapy for Semen Parameters and Pregnancy and Live Birth Rates in Couples with Idiopathic Infertility : A Systematic Review and Meta-analysis
The authors would like to thank Julie Darraugh and Karin Plass from the EAU Guidelines Office for their assistance with the systematic review.Peer reviewedPostprin
Optimal trapping wavelengths of Cs molecules in an optical lattice
The present paper aims at finding optimal parameters for trapping of Cs
molecules in optical lattices, with the perspective of creating a quantum
degenerate gas of ground-state molecules. We have calculated dynamic
polarizabilities of Cs molecules subject to an oscillating electric field,
using accurate potential curves and electronic transition dipole moments. We
show that for some particular wavelengths of the optical lattice, called "magic
wavelengths", the polarizability of the ground-state molecules is equal to the
one of a Feshbach molecule. As the creation of the sample of ground-state
molecules relies on an adiabatic population transfer from weakly-bound
molecules created on a Feshbach resonance, such a coincidence ensures that both
the initial and final states are favorably trapped by the lattice light,
allowing optimized transfer in agreement with the experimental observation
Quantitative Analysis of the Density of Trap States at the Semiconductor-Dielectric Interface in Organic Field-Effect Transistors
The electrical properties of organic field-effect transistors are governed by the quality of the constituting layers, and the resulting interfaces. We compare the properties of the same organic semiconductor film, 2,8-difluoro- 5,11-bis (triethylsilylethynyl) anthradithiophene, with bottom SiO2 dielectric and top Cytop dielectric and find a 10× increase in charge carrier mobility, from 0.17 ± 0.19 cm2 V−1 s−1 to 1.5 ± 0.70 cm2 V−1 s−1, when the polymer dielectric is used. This results from a significant reduction of the trap density of states in the semiconductor band-gap, and a decrease in the contact resistance
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