Robustness and modular design of the Drosophila segment polarity network

Biomolecular networks have to perform their functions robustly. A robust function may have preferences in the topological structures of the underlying network. We carried out an exhaustive computational analysis on network topologies in relation to a patterning function in Drosophila embryogenesis. We found that while the vast majority of topologies can either not perform the required function or only do so very fragilely, a small fraction of topologies emerges as particularly robust for the function. The topology adopted by Drosophila, that of the segment polarity network, is a top ranking one among all topologies with no direct autoregulation. Furthermore, we found that all robust topologies are modular--each being a combination of three kinds of modules. These modules can be traced back to three sub-functions of the patterning function and their combinations provide a combinatorial variability for the robust topologies. Our results suggest that the requirement of functional robustness drastically reduces the choices of viable topology to a limited set of modular combinations among which nature optimizes its choice under evolutionary and other biological constraints.Comment: Supplementary Information and Synopsis available at http://www.ucsf.edu/tanglab

Hadronic production of the PP-wave excited BcB_c-states (BcJ,L=1∗B_{cJ,L=1}^*)

Adopting the complete $\alpha_s^4$ approach of the perturbative QCD (pQCD) and updated parton distribution functions, we have estimated the hadronic production of $P$-wave excited $B_c$-states ($B_{cJ,L=1}^*$). In the estimate, special care on the relation of the production amplitude to the derivative of wave function at origin of the potential model is payed. For experimental references, main uncertainties are discussed, and the total cross sections and the distributions of the production with reasonable cuts at the energies of Tevatron and LHC are computed and presented. The results show that $P$-wave production may contribute to the $B_c$-meson production indirectly by a factor about 0.5 of the direct production, and with such a big cross section, it is worth further to study the possibility to observe the $P$-wave production itself experimentally.Comment: 23 pages, 9 figures, to replace for revising the misprints ec

Properties of the Molecular Cores of Low Luminosity Objects

We present a survey toward 16 Low Luminosity Objects (LLOs with an internal luminosity, Lint, lower than 0.2 Lsun) with N2H+ (1-0), N2H+ (3-2), N2D+ (3-2), HCO+ (3-2) and HCN (3-2) using the Arizona Radio Observatory Kitt Peak 12m Telescope and Submillimeter Telescope. Our goal is to probe the nature of these faint protostars which are believed to be either very low mass or extremely young protostars. We find that the N2D+/N2H+ column density ratios of LLOs are similar to those of typical starless cores and Class 0 objects. The N2D+/N2H+ column density ratios are relatively high (> 0.05) for LLOs with kinetic temperatures less than 10 K in our sample. The distribution of N2H+ (1-0) line widths spreads between that of starless cores and young Class 0 objects. If we use the line width as a dynamic evolutionary indicator, LLOs are likely young Class 0 protostellar sources. We further use the optically thick tracers, HCO+ (3-2) and HCN (3-2), to probe the infall signatures of our targets. We derive the asymmetry parameters from both lines and estimate the infall velocities by fitting the HCO+ (3-2) spectra with two-layer models. As a result, we identify eight infall candidates based on the infall velocities and seven candidates have infall signatures supported by asymmetry parameters from at least one of HCO+ (3-2) and HCN (3-2).Comment: 15 pages, 8 figures, accepted to Ap

Analyzing the influential factors of industry 4.0 in precision machinery industry

Abstract. Nowadays the science and technology progresses not only create the change to have a big impact on various industries, but also stimulate Industry 4.0 being applied in the manufacturing industry to achieve manufacturing efficiency and to reduce its cost to increase additional values. This study uses the Analytical Hierarchical Process (AHP) evaluation method, which considers four criteria layers: Internet of things factors, Automationfactors, Intelligent factors, Big data factors, and twelve influence factors in sub-layer are: perceived layer, network layer, application layer, field layer, management layer, control layer, process control visualization, system supervisory and control omni bearing, green energy manufacturing production, variety, volume, and velocity. Then, the relative risk indicator (RRI) is obtained by the Analytical Hierarchical Process method, and the overall risk indicator (ORI) can be obtained after introducing the evaluation value of each impact factor through the case. The research results confirm that the risk assessment values obtained the hierarchical analysis method are consistent. This research through the Analytic Hierarchy Process, then discusses Industry 4.0 pair of Taiwan's precision machinery industry management pattern institute emphatically face with target, expected will provide the existing machine manufacture industry as well as the future wants to invest the precision machine industry the management policy-maker reference value, also might take the government policy consideration factors and the machine manufacture industry scholars study the academic for reference.Keywords. Industry 4.0, Precision machine industry, Analytic Hierarchy Process.JEL. L22, M11, O14