38 research outputs found
Trade-offs among cost, integration, and segregation in the human connectome
AbstractThe human brain structural network is thought to be shaped by the optimal trade-off between cost and efficiency. However, most studies on this problem have focused on only the trade-off between cost and global efficiency (i.e., integration) and have overlooked the efficiency of segregated processing (i.e., segregation), which is essential for specialized information processing. Direct evidence on how trade-offs among cost, integration, and segregation shape the human brain network remains lacking. Here, adopting local efficiency and modularity as segregation factors, we used a multiobjective evolutionary algorithm to investigate this problem. We defined three trade-off models, which represented trade-offs between cost and integration (Dual-factor model), and trade-offs among cost, integration, and segregation (local efficiency or modularity; Tri-factor model), respectively. Among these, synthetic networks with optimal trade-off among cost, integration, and modularity (Tri-factor model [Q]) showed the best performance. They had a high recovery rate of structural connections and optimal performance in most network features, especially in segregated processing capacity and network robustness. Morphospace of this trade-off model could further capture the variation of individual behavioral/demographic characteristics in a domain-specific manner. Overall, our results highlight the importance of modularity in the formation of the human brain structural network and provide new insights into the original cost-efficiency trade-off hypothesis
An initial assessment of SMAP soil moisture retrievals using high-resolution model simulations and in situ observations
At the end of its first year of operation, we compare soil moisture retrievals from the Soil Moisture Active Passive (SMAP) mission to simulations from a land surface model with meteorological forcing downscaled from observations/reanalysis and in situ observations from sparse monitoring networks within continental United States (CONUS). The radar failure limits the duration of comparisons for the active and combined products (~3 months). Nevertheless, the passive product compares very well against in situ observations over CONUS. On average, SMAP compares to the in situ data even better than the land surface model and provides significant added value on top of the model and thus good potential for data assimilation. At large scale, SMAP is in good agreement with the model in most of CONUS with less-than-expected degradation over mountainous areas. Lower correlation between SMAP and the model is seen in the forested east CONUS and significantly lower over the Canadian boreal forests.United States. National Aeronautics and Space Administration (NNX14AH92G)United States. National Aeronautics and Space Administration (NNX13AI44G
Characterization of a novel qepA3 variant in Enterobacter aerogenes
Five isolates harboring qepA were studied by polymerase chain reaction (PCR) amplification and relevant methods. One was determined to be a novel qepA3 from Enterobacter aerogenes, and four involved three qepA1 and one qepA2 determinants from Escherichia coli; the qepA3 changed five amino acids. These results characterized genetic structures A, B, C, D, and E
Knowledge Graph-Based Assembly Resource Knowledge Reuse towards Complex Product Assembly Process
Assembly process designers typically confront the challenge of seeking information out of large volumes of non-structured files with a view to supporting the decision-making to be made. It is a leading concern that embedding data in text documents can hardly be retrieved semantically in order to facilitate decision-making with timely support. For tackling this gap, we propose in this paper a knowledge graph-based approach used to merge and retrieve information decided to be relevant within an engineering context. The proposed approach is to establish a multidimensional integrated assembly resource knowledge graph (ARKG) based on the structure of function-structure-assembly procedure-assembly resource, and this multidimensional integrated structure can well accomplish the retrieval of related knowledge. The upper semantic framework of ARKG is established by the assembly resource ontology model, which is a semantic-type framework involving multiple domains of knowledge to create instantiated data reflecting the full profile of the assembly resource for obtaining structured data of ARKG while avoiding the data redundancy problem. The ARKG method is validated through assembly scenario of the aircraft, and the results show the effectiveness and accuracy of the ARKG used by the assembly process designer in the assembly process design phase for retrieving the target knowledge of the assembly resources
Knowledge Graph-Based Assembly Resource Knowledge Reuse towards Complex Product Assembly Process
Assembly process designers typically confront the challenge of seeking information out of large volumes of non-structured files with a view to supporting the decision-making to be made. It is a leading concern that embedding data in text documents can hardly be retrieved semantically in order to facilitate decision-making with timely support. For tackling this gap, we propose in this paper a knowledge graph-based approach used to merge and retrieve information decided to be relevant within an engineering context. The proposed approach is to establish a multidimensional integrated assembly resource knowledge graph (ARKG) based on the structure of function-structure-assembly procedure-assembly resource, and this multidimensional integrated structure can well accomplish the retrieval of related knowledge. The upper semantic framework of ARKG is established by the assembly resource ontology model, which is a semantic-type framework involving multiple domains of knowledge to create instantiated data reflecting the full profile of the assembly resource for obtaining structured data of ARKG while avoiding the data redundancy problem. The ARKG method is validated through assembly scenario of the aircraft, and the results show the effectiveness and accuracy of the ARKG used by the assembly process designer in the assembly process design phase for retrieving the target knowledge of the assembly resources
Tuning Dielectric Loss of SiO2@CNTs for Electromagnetic Wave Absorption
We developed a simple method to fabricate SiO2-sphere-supported N-doped CNTs (NCNTs) for electromagnetic wave (EMW) absorption. EMW absorption was tuned by adsorption of the organic agent on the precursor of the catalysts. The experimental results show that the conductivity loss and polarization loss of the sample are improved. Meanwhile, the impedance matching characteristics can also be adjusted. When the matching thickness was only 1.5 mm, the optimal 3D structure shows excellent EMW absorption performance, which is better than most magnetic carbon matrix composites. Our current approach opens up an effective way to develop low-cost, high-performance EMW absorbers
Coupling Hollow Fe<sub>3</sub>O<sub>4</sub>–Fe Nanoparticles with Graphene Sheets for High-Performance Electromagnetic Wave Absorbing Material
We developed a strategy for coupling
hollow Fe<sub>3</sub>O<sub>4</sub>–Fe nanoparticles with graphene
sheets for high-performance electromagnetic wave absorbing material.
The hollow Fe<sub>3</sub>O<sub>4</sub>–Fe nanoparticles with
average diameter and shell thickness of 20 and 8 nm, respectively,
were uniformly anchored on the graphene sheets without obvious aggregation.
The minimal reflection loss <i>R</i><sub>L</sub> values
of the composite could reach −30 dB at the absorber thickness
ranging from 2.0 to 5.0 mm, greatly superior to the solid Fe<sub>3</sub>O<sub>4</sub>–Fe/G composite and most magnetic EM wave absorbing
materials recently reported. Moreover, the addition amount of the
composite into paraffin matrix was only 18 wt %
Electrostatic Trapping of Double-Stranded DNA Based on Cd(OH)<sub>2</sub> Three-Side Nanobelt Architectures
In
this paper, CdÂ(OH)<sub>2</sub> 1D three-side nanobelt architectures
have been fabricated through a facile two-phase reaction system. Considering
their electropositive character proven by zeta potential measurement,
the as-obtained CdÂ(OH)<sub>2</sub> nanomaterials have been applied
to capture negatively charged DNA. On the basis of the above results,
the CdÂ(OH)<sub>2</sub> nanomaterials have been employed for trapping
negatively charged double-stranded DNA molecules (salmon sperm DNA).
Assisted by the detailed observation of their DNA interaction results
as well as through UV–vis spectroscopy, infrared imaging automatic
target recognition (IRATR) and inductive coupled plasma atomic emission
spectrometer (ICP-AES) measurements, it has been clearly shown that
this 1D nanoarchitecture can effectively trap and release DNA molecules
without use of any other organic reagents. In addition, a miniaturized
electrochemical DNA-releasing device based on the CdÂ(OH)<sub>2</sub> 1D three-side nanobelt architectures has been fabricated. Using
this device, it is possible to recycle the CdÂ(OH)<sub>2</sub> nanostructures.
In addition, the CdÂ(OH)<sub>2</sub> nanomaterials maintain their nanostructures,
and no Cd<sup>2+</sup> ions were released in repeated DNA separation
and transfer processes, which demonstrate their practicality for DNA
trapping
Terahertz Spectroscopy for Accurate Identification of Panax quinquefolium Basing on Nonconjugated 24(R)-Pseudoginsenoside F11
Panax quinquefolium is a perennial herbaceous plant that contains many beneficial ginsenosides with diverse pharmacological effects. 24(R)-pseudoginsenoside F11 is specific to P. quinquefolium, a useful biomarker for distinguishing this species from other related plants. However, because of its nonconjugated property and the complexity of existing detection methods, this biomarker cannot be used as the identification standard. We herein present a stable 24(R)-pseudoginsenoside F11 fingerprint spectrum in the terahertz band, thereby proving that F11 can be detected and quantitatively analyzed via terahertz spectroscopy. We also analyzed the sample by high-performance liquid chromatography-triple quadrupole mass spectrometry. The difference between the normalized data for the two analytical methods was less than 5%. Furthermore, P. quinquefolium from different areas and other substances can be clearly distinguished based on these terahertz spectra with a standard principal component analysis. Our method is a fast, simple, and cost-effective approach for identifying and quantitatively analyzing P. quinquefolium