1,672 research outputs found
Recommended from our members
Beyond absorptive capacity in open innovation process: the relationships between openness, capacities and firm performance
The literature has shown that open innovation (OI) can be a winning strategy in improving firm performance. However, in order to adopt and implement it, managers need to resolve practical problems, such as understanding the role played by OI capacities and openness on firm performance. In response to these needs, this study aims to investigate the hierarchical relationships between openness, OI capacities and performance using a structural equation model approach. This paper also attempts to compare the levels of openness between firms in different industries to discover similarities and differences in OI phenomena. The analysis of data obtained from a survey of Korean firms shows significant interrelations between openness, OI capacities and firm performance. Our results go further in developing understanding of the building blocks on which successful OI is built and particularly suggest that desorptive capacity which underpins the out-bound OI process, is in turn strongly supported by knowledge management capacity. It is hoped that the results of this study can enrich our understanding of the OI mechanism *and provide managerial and policy implications.This is the author accepted manuscript. The final version is available from Taylor & Francis via http://dx.doi.org/10.1080/09537325.2016.118173
Quantum Holographic Encoding in a Two-dimensional Electron Gas
The advent of bottom-up atomic manipulation heralded a new horizon for
attainable information density, as it allowed a bit of information to be
represented by a single atom. The discrete spacing between atoms in condensed
matter has thus set a rigid limit on the maximum possible information density.
While modern technologies are still far from this scale, all theoretical
downscaling of devices terminates at this spatial limit. Here, however, we
break this barrier with electronic quantum encoding scaled to subatomic
densities. We use atomic manipulation to first construct open
nanostructures--"molecular holograms"--which in turn concentrate information
into a medium free of lattice constraints: the quantum states of a
two-dimensional degenerate Fermi gas of electrons. The information embedded in
the holograms is transcoded at even smaller length scales into an atomically
uniform area of a copper surface, where it is densely projected into both two
spatial degrees of freedom and a third holographic dimension mapped to energy.
In analogy to optical volume holography, this requires precise amplitude and
phase engineering of electron wavefunctions to assemble pages of information
volumetrically. This data is read out by mapping the energy-resolved electron
density of states with a scanning tunnelling microscope. As the projection and
readout are both extremely near-field, and because we use native quantum states
rather than an external beam, we are not limited by lensing or collimation and
can create electronically projected objects with features as small as ~0.3 nm.
These techniques reach unprecedented densities exceeding 20 bits/nm2 and place
tens of bits into a single fermionic state.Comment: Published online 25 January 2009 in Nature Nanotechnology; 12 page
manuscript (including 4 figures) + 2 page supplement (including 1 figure);
supplementary movie available at http://mota.stanford.ed
Groups without cultured representatives dominate eukaryotic picophytoplankton in the oligotrophic South East Pacific Ocean
Background: Photosynthetic picoeukaryotes (PPE) with a cell size less than 3 ”m play a critical role in oceanic primary production. In recent years, the composition of marine picoeukaryote communities has been intensively investigated by molecular approaches, but their photosynthetic fraction remains poorly characterized. This is largely because the classical approach that relies on constructing 18S rRNA gene clone libraries from filtered seawater samples using universal eukaryotic primers is heavily biased toward heterotrophs, especially alveolates and stramenopiles, despite the fact that autotrophic cells in general outnumber heterotrophic ones in the euphotic zone.
Methodology/Principal Findings: In order to better assess the composition of the eukaryotic picophytoplankton in the South East Pacific Ocean, encompassing the most oligotrophic oceanic regions on earth, we used a novel approach based on flow cytometry sorting followed by construction of 18S rRNA gene clone libraries. This strategy dramatically increased the recovery of sequences from putative autotrophic groups. The composition of the PPE community appeared highly variable both vertically down the water column and horizontally across the South East Pacific Ocean. In the central gyre, uncultivated lineages dominated: a recently discovered clade of Prasinophyceae (IX), clades of marine Chrysophyceae and Haptophyta, the latter division containing a potentially new class besides Prymnesiophyceae and Pavlophyceae. In contrast, on the edge of the gyre and in the coastal Chilean upwelling, groups with cultivated representatives (Prasinophyceae clade VII and Mamiellales) dominated.
Conclusions/Significance: Our data demonstrate that a very large fraction of the eukaryotic picophytoplankton still escapes cultivation. The use of flow cytometry sorting should prove very useful to better characterize specific plankton populations by molecular approaches such as gene cloning or metagenomics, and also to obtain into culture strains representative of these novel groups
How and why DNA barcodes underestimate the diversity of microbial eukaryotes
Background: Because many picoplanktonic eukaryotic species cannot currently be maintained in culture, direct sequencing of PCR-amplified 18S ribosomal gene DNA fragments from filtered sea-water has been successfully used to investigate the astounding diversity of these organisms. The recognition of many novel planktonic organisms is thus based solely on their 18S rDNA sequence. However, a species delimited by its 18S rDNA sequence might contain many cryptic species, which are highly differentiated in their protein coding sequences. Principal Findings: Here, we investigate the issue of species identification from one gene to the whole genome sequence. Using 52 whole genome DNA sequences, we estimated the global genetic divergence in protein coding genes between organisms from different lineages and compared this to their ribosomal gene sequence divergences. We show that this relationship between proteome divergence and 18S divergence is lineage dependant. Unicellular lineages have especially low 18S divergences relative to their protein sequence divergences, suggesting that 18S ribosomal genes are too conservative to assess planktonic eukaryotic diversity. We provide an explanation for this lineage dependency, which suggests that most species with large effective population sizes will show far less divergence in 18S than protein coding sequences. Conclusions: There is therefore a trade-off between using genes that are easy to amplify in all species, but which by their nature are highly conserved and underestimate the true number of species, and using genes that give a better description of the number of species, but which are more difficult to amplify. We have shown that this trade-off differs between unicellular and multicellular organisms as a likely consequence of differences in effective population sizes. We anticipate that biodiversity of microbial eukaryotic species is underestimated and that numerous ''cryptic species'' will become discernable with the future acquisition of genomic and metagenomic sequences
First step to facilitate long term and multi centre studies of shear wave elastography in solid breast lesions using a computer assisted algorithm
Purpose:
Shear wave elastography (SWE) visualises the elasticity of tissue. As malignant tissue is generally stiffer than benign tissue, SWE is helpful to diagnose solid breast lesions. Until now, quantitative measurements of elasticity parameters have been possible only, while the images were still saved on the ultrasound imaging device. This work aims to overcome this issue and introduces an algorithm allowing fast offline evaluation of SWE images.
Methods:
The algorithm was applied to a commercial phantom comprising three lesions of various elasticities and 207 in vivo solid breast lesions. All images were saved in DICOM, JPG and QDE (quantitative data export; for research only) format and evaluated according to our clinical routine using a computer-aided diagnosis algorithm. The results were compared to the manual evaluation (experienced radiologist and trained engineer) regarding their numerical discrepancies and their diagnostic performance using ROC and ICC analysis.
Results:
ICCs of the elasticity parameters in all formats were nearly perfect (0.861â0.990). AUC for all formats was nearly identical for and (0.863â0.888). The diagnostic performance of SD using DICOM or JPG estimations was lower than the manual or QDE estimation (AUC 0.673 vs. 0.844).
Conclusions:
The algorithm introduced in this study is suitable for the estimation of the elasticity parameters offline from the ultrasound system to include images taken at different times and sites. This facilitates the performance of long-term and multi-centre studies
IL-12p40 Homodimer Ameliorates Experimental Autoimmune Arthritis
IL-23 is the key cytokine that induces the expansion of Th17 cells. It is composed of p19 and p40 subunits of IL-12. The p40 subunit binds competitively to the receptor of IL-23 and blocks its activity. Our aim was to assess the preventive and therapeutic effect of the IL-12p40 homodimer (p40)(2) subunit in autoimmune arthritis animal models. In the current study, using IL-1R antagonist-knockout mice and a collagen-induced arthritis model, we investigated the suppressive effect of (p40)(2) on inflammatory arthritis. We demonstrated that the recombinant adenovirus-expressing mouse (p40)(2) model prevented the development of arthritis when given before the onset of arthritis. It also decreased the arthritis index and joint erosions in the mouse model if transferred after arthritis was established. (p40)(2) inhibited the production of inflammatory cytokines and Ag-specific T cell proliferation. It also induced CD4(+)CD25(+)Foxp3 regulatory T (Treg) cells in vitro and in vivo, whereas the generation of retinoic acid receptor-related organ receptor gamma t and Th17 cells was suppressed. The induction of Treg cells and the suppression of Th17 cells were mediated via activated STAT5 and suppressed STAT3. Our data suggest that (p40)(2) suppressed inflammatory arthritis successfully. This could be a useful therapeutic approach in autoimmune arthritis to regulate the Th17/Treg balance and IL-23 signaling.1156Ysciescopu
Recommended from our members
High-efficiency photovoltaic cells with wide optical band gap polymers based on fluorinated phenylene-alkoxybenzothiadiazole
A series of semi-crystalline, wide band gap (WBG) photovoltaic polymers were synthesized with varying number and topology of fluorine substituents. To decrease intramolecular charge transfer and to modulate the resulting band gap of D-A type copolymers, electron-releasing alkoxy substituents were attached to electron-deficient benzothiadiazole (A) and electron-withdrawing fluorine atoms (0-4F) were substituted onto a 1,4-bis(thiophen-2-yl)benzene unit (D). Intra- and/or interchain noncovalent Coulombic interactions were also incorporated into the polymer backbone to promote planarity and crystalline intermolecular packing. The resulting optical band gap and the valence level were tuned to 1.93-2.15 eV and -5.37 to -5.67 eV, respectively, and strong interchain organization was observed by differential scanning calorimetry, high-resolution transmission electron microscopy and grazing incidence X-ray scattering measurements. The number of fluorine atoms and their position significantly influenced the photophysical, morphological and optoelectronic properties of bulk heterojunctions (BHJs) with these polymers. BHJ photovoltaic devices showed a high power conversion efficiency (PCE) of up to 9.8% with an open-circuit voltage of 0.94-1.03 V. To our knowledge, this PCE is one of the highest values for fullerene-based single BHJ devices with WBG polymers having a band gap of over 1.90 eV. A tandem solar cell was also demonstrated successfully to show a PCE of 10.3% by combining a diketopyrrolopyrrole-based low band gap polymer
Relativistic ejecta from XRF 060218 and the rate of cosmic explosions
Over the last decade, long-duration gamma-ray bursts (GRBs) including the
subclass of X-ray flashes (XRFs) have been revealed to be a rare variety of
Type Ibc supernova (SN). While all these events result from the death of
massive stars, the electromagnetic luminosities of GRBs and XRFs exceed those
of ordinary Type Ibc SNe by many orders of magnitude. The essential physical
process that causes a dying star to produce a GRB or XRF, and not just an SN,
remains the crucial open question. Here we present radio and X-ray observations
of XRF 060218 (associated with SN 2006aj), the second nearest GRB identified
to-date, which allow us to measure its total energy and place it in the larger
context of cosmic explosions. We show that this event is 100 times less
energetic but ten times more common than cosmological GRBs. Moreover, it is
distinguished from ordinary Type Ibc SNe by the presence of 10^48 erg coupled
to mildly-relativistic ejecta, along with a central engine (an accretion-fed,
rapidly rotating compact source) which produces X-rays for weeks after the
explosion. This suggests that the production of relativistic ejecta is the key
physical distinction between GRBs/XRFs and ordinary SNe, while the nature of
the central engine (black hole or magnetar) may distinguish typical bursts from
low-luminosity, spherical events like XRF 060218.Comment: To appear in Nature on August 31 2006 (15 pages, 3 figures, 1 table,
including Supplementary Information
Potential health impacts of heavy metals on HIV-infected population in USA.
Noninfectious comorbidities such as cardiovascular diseases have become increasingly prevalent and occur earlier in life in persons with HIV infection. Despite the emerging body of literature linking environmental exposures to chronic disease outcomes in the general population, the impacts of environmental exposures have received little attention in HIV-infected population. The aim of this study is to investigate whether individuals living with HIV have elevated prevalence of heavy metals compared to non-HIV infected individuals in United States. We used the National Health and Nutrition Examination Survey (NHANES) 2003-2010 to compare exposures to heavy metals including cadmium, lead, and total mercury in HIV infected and non-HIV infected subjects. In this cross-sectional study, we found that HIV-infected individuals had higher concentrations of all heavy metals than the non-HIV infected group. In a multivariate linear regression model, HIV status was significantly associated with increased blood cadmium (p=0.03) after adjusting for age, sex, race, education, poverty income ratio, and smoking. However, HIV status was not statistically associated with lead or mercury levels after adjusting for the same covariates. Our findings suggest that HIV-infected patients might be significantly more exposed to cadmium compared to non-HIV infected individuals which could contribute to higher prevalence of chronic diseases among HIV-infected subjects. Further research is warranted to identify sources of exposure and to understand more about specific health outcomes
- âŠ