Scaling Behaviors of Weighted Food Webs as Energy Transportation Networks

Food webs can be regarded as energy transporting networks in which the weight of each edge denotes the energy flux between two species. By investigating 21 empirical weighted food webs as energy flow networks, we found several ubiquitous scaling behaviors. Two random variables $A_i$ and $C_i$ defined for each vertex $i$, representing the total flux (also called vertex intensity) and total indirect effect or energy store of $i$, were found to follow power law distributions with the exponents $\alpha\approx 1.32$ and $\beta\approx 1.33$, respectively. Another scaling behavior is the power law relationship, $C_i\sim A_i^\eta$, where $\eta\approx 1.02$. This is known as the allometric scaling power law relationship because $A_i$ can be treated as metabolism and $C_i$ as the body mass of the sub-network rooted from the vertex $i$, according to the algorithm presented in this paper. Finally, a simple relationship among these power law exponents, $\eta=(\alpha-1)/(\beta-1)$, was mathematically derived and tested by the empirical food webs

Establishment of porcine and human expanded potential stem cells.

We recently derived mouse expanded potential stem cells (EPSCs) from individual blastomeres by inhibiting the critical molecular pathways that predispose their differentiation. EPSCs had enriched molecular signatures of blastomeres and possessed developmental potency for all embryonic and extra-embryonic cell lineages. Here, we report the derivation of porcine EPSCs, which express key pluripotency genes, are genetically stable, permit genome editing, differentiate to derivatives of the three germ layers in chimeras and produce primordial germ cell-like cells in vitro. Under similar conditions, human embryonic stem cells and induced pluripotent stem cells can be converted, or somatic cells directly reprogrammed, to EPSCs that display the molecular and functional attributes reminiscent of porcine EPSCs. Importantly, trophoblast stem-cell-like cells can be generated from both human and porcine EPSCs. Our pathway-inhibition paradigm thus opens an avenue for generating mammalian pluripotent stem cells, and EPSCs present a unique cellular platform for translational research in biotechnology and regenerative medicine

From MetroII to Metronomy, Designing Contract-based Function-Architecture Co-simulation Framework for Timing Verification of Cyber-Physical Systems

As the design complexity of cyber-physical systems continues to grow, modeling the system at higher abstraction levels with formal models of computation is increasingly appealing since it enables early design verification and analysis. However, it is very challenging to analyze and verify timing at the early design stages, as the design representation is still abstract and trade-offs have to be made between the performance requirements defined in terms of system functionality and the cost of the feasible architecture that can implement the functionality. In this work, we present Metronomy, a function-architecture co-simulation framework that integrates functional modeling from Ptolemy and architectural modeling from the MetroII environment via a mapping interface. Metronomy completely separates the function and architecture modeling. It allows the function and the architecture of the system to be modeled in the most suitable design environments. At the same time, Metronomy allows designers to do timing verification and design space exploration at early design stage by exploiting contract theory and co-simulation. Two case studies on an electrical power system and a paper-feed sub-system for a high speed printing press demonstrate the effectiveness of our approach

Integration of Correct-by-Construction BIP Models into the MetroII Design Space Exploration Flow

Design correctness and performance are major issues which are usually considered separately, and with different emphasis, by traditional system design flows. In this paper we show that one can meaningfully connect and benefit from the advantages of two design frameworks, with different design goals. We consider BIP for high-level rigorous design and correct-by-construction implementation, and METROII, for low-level platform-based design and performance evaluation

Integration of Correct-by-Construction BIP Models into the MetroII Design Space Exploration Flow We consider BIP for high-level rigorous design and correct- by-construction implementation, and METROII, for low-level platform-based design and performance e

Abstract-Design correctness and performance are major issues which are usually considered separately, and with different emphasis, by traditional system design flows. In this paper we show that one can meaningfully connect and benefit from the advantages of two design frameworks, with different design goals

Anti-Fouling Performance of Hydrophobic Hydrogels with Unique Surface Hydrophobicity and Nanoarchitectonics

Hydrogel is a kind of soft and wet matter, which demonstrates favorable fouling resistance owing to the hydration anti-adhesive surfaces. Different from conventional hydrogels constructed by hydrophilic or amphiphilic polymers, the recently invented “hydrophobic hydrogels” composed of hydrophobic polymers exhibit many unique properties, e.g., surface hydrophobicity and high water content, suggesting promising applications in anti-fouling. In this paper, a series of hydrophobic hydrogels were prepared with different chemical structures and water content for anti-fouling investigations. The hydrophobic hydrogels showed high static water contact angles (WCAs > 90°), indicating remarkable surface hydrophobicity, which is abnormal for conventional hydrogels. Compared with the conventional hydrogels, all the hydrophobic hydrogels exhibited less than 4% E. coli biofilm coverage, showing a contrary trend of anti-fouling ability to the water content inside the polymer. Typically, the poly(2-(2-ethoxyethoxy)ethyl acrylate) (PCBA) and poly(tetrahydrofurfuryl acrylate) (PTHFA) hydrogels with relatively high surface hydrophobicity showed as low as 5.1% and 2.4% E. coli biofilm coverage even after incubation for 7 days in bacteria suspension, which are about 0.32 and 0.15 times of that on the hydrophilic poly(N,N-dimethylacrylamide) (PDMA) hydrogels, respectively. Moreover, the hydrophobic hydrogels exhibited a similar anti-adhesion ability and trend to algae S. platensis. Based on the results, the surface hydrophobicity mainly contributes to the excellent anti-fouling ability of hydrophobic hydrogels. In the meantime, the too-high water content may be somehow detrimental to anti-fouling performance

Metronomy

As the design complexity of cyber-physical systems continues to grow, modeling the system at higher abstraction levels with formal models of computation is increasingly appealing since it enables early design verification and analysis. One of the most important aspects in system modeling and analysis is timing. However, it is very challenging to analyze and verify timing at the early design stages, as the design representation is quite abstract and trade-offs have to be made between the performance requirements defined in terms of system functionality and the cost of the feasible architecture that can implement the functionality. In this paper, we present Metronomy, a function-architecture cosimulation framework that integrates functional modeling from Ptolemy and architectural modeling from the MetroII environment via a mapping interface. Metronomy exploits contract theory for timing verification and design space exploration via co-simulation. Two case studies on an electrical power system and a paper-feed sub-system for a high speed printing press demonstrate the effectiveness of our approach. Copyright 2014 ACM

A Thunderstorm Gale Forecast Method Based on the Objective Classification and Continuous Probability

Potential prediction is an important research content of thunderstorm gale weather forecast, and it is still a challenge because the environmental field of thunderstorm gale presents different characteristics under different weather conditions. Using the 12-year thunderstorm gale data of Hubei province in central China and the reanalysis data of National Center for Environmental Prediction (NCEP), this study analyzed the percentile distribution of environmental physical quantities of thunderstorm gale, and the continuous probability method was adopted to establish the probability forecast models of thunderstorm gale in four different types of weather situation, which are in the rear of trough type, in front of trough type, in the periphery of the western Pacific subtropical high type and easterly airflow type. Finally, probability prediction was realized by objective classification criterion in operation. The results show that the method based on objective classification and continuous probability can significantly improve the probability of thunderstorm gale detection, and also reduce the missing alarm rate of thunderstorm gale. Moreover, the quantitative test of 16 weather processes under four types of weather situations also shows that the continuous probability method has a higher probability of detection than the bisection method, and significantly reduces the missing alarm of extreme wind by the bisection method

The relative contribution of paracine effect versus direct differentiation on adipose-derived stem cell transplantation mediated cardiac repair.

BACKGROUND: Recent studies have demonstrated that transplantation of adipose-derived stem cell (ADSC) can improve cardiac function in animal models of myocardial infarction (MI). However, the mechanisms underlying the beneficial effect are not fully understood. In this study, we characterized the paracrine effect of transplanted ADSC and investigated its relative importance versus direct differentiation in ADSC transplantation mediated cardiac repair. METHODOLOGY/PRINCIPAL FINDINGS: MI was experimentally induced in mice by ligation of the left anterior descending coronary artery. Either human ADSC, conditioned medium (CM) collected from the same amount of ADSC or control medium was injected into the peri-infarct region immediately after MI. Compared with the control group, both ADSC and ADSC-CM significantly reduced myocardial infarct size and improved cardiac function. The therapeutic efficacy of ADSC was moderately superior to ADSC-CM. ADSC-CM significantly reduced cardiomyocyte apoptosis in the infarct border zone, to a similar degree with ADSC treatment. ADSC enhanced angiogenesis in the infarct border zone, but to a stronger degree than that seen in the ADSC-CM treatment. ADSC was able to differentiate to endothelial cell and smooth muscle cell in post-MI heart; these ADSC-derived vascular cells amount to about 9% of the enhanced angiogenesis. No cardiomyocyte differentiated from ADSC was found. CONCLUSIONS: ADSC-CM is sufficient to improve cardiac function of infarcted hearts. The therapeutic function of ADSC transplantation is mainly induced by paracrine-mediated cardioprotection and angiogenesis, while ADSC differentiation contributes a minor benefit by being involved in angiogenesis. Highlights 1 ADSC-CM is sufficient to exert a therapeutic potential. 2. ADSC was able to differentiate to vascular cells but not cardiomyocyte. 3. ADSC derived vascular cells amount to about 9% of the enhanced angiogenesis. 4. Paracrine effect is the major mechanism of ADSC therapeutic function for MI