The role of bipartite structure in R&D collaboration networks

A number of real-world networks are, in fact, one-mode projections of bipartite networks comprised of two types of nodes. For institutions engaging in collaboration for technological innovation, the underlying network is bipartite with institutions (agents) linked to the patents they have filed (artifacts), while the projection is the co-patenting network. Projected network topology is highly affected by the underlying bipartite structure, hence a lack of understanding of the bipartite network has consequences for the information that might be drawn from the one-mode co-patenting network. Here, we create an empirical bipartite network using data from 2.7 million patents. We project this network onto the agents (institutions) and look at properties of both the bipartite and projected networks that may play a role in knowledge sharing and collaboration. We compare these empirical properties to those of synthetic bipartite networks and their projections in order to understand the processes that might operate in the network formation. A good understanding of the topology is critical for investigating the potential flow of technological knowledge. We show how degree distributions and small cycles affect the topology of the one-mode projected network - specifically degree and clustering distributions, and assortativity. We propose new network-based metrics to quantify how collaborative agents are in the co-patenting network. We find that several large corporations that are the most collaborative agents in the network, however such organisations tend to have a low diversity of collaborators. In contrast, the most prolific institutions tend to collaborate relatively little but with a diverse set of collaborators. This indicates that they concentrate the knowledge of their core technical research, while seeking specific complementary knowledge via collaboration with smaller companies.Comment: 23 pages, 12 figures, 2 table

New partitioning perturbation theory. 2 - Example of almost degeneracy

Degeneracy applications to partitioning perturbation theory - Part

Time-dependent perturbation of a two-state quantum mechanical system

A two- (nondegenerate) level quantum system interacting with a classical monochromatic radiation field is described. The existing work on this problem is reviewed and some novel aspects of the problems are presented

Reaching optimally oriented molecular states by laser kicks

We present a strategy for post-pulse orientation aiming both at efficiency and maximal duration within a rotational period. We first identify the optimally oriented states which fulfill both requirements. We show that a sequence of half-cycle pulses of moderate intensity can be devised for reaching these target states.Comment: 4 pages, 3 figure

Laser control for the optimal evolution of pure quantum states

Starting from an initial pure quantum state, we present a strategy for reaching a target state corresponding to the extremum (maximum or minimum) of a given observable. We show that a sequence of pulses of moderate intensity, applied at times when the average of the observable reaches its local or global extremum, constitutes a strategy transferable to different control issues. Among them, post-pulse molecular alignment and orientation are presented as examples. The robustness of such strategies with respect to experimentally relevant parameters is also examined.Comment: 16 pages, 9 figure

Kajian Rumput Laut Sargassum Duplicatum J. G. Agardh Sebagai Penghasil Bioetanol Dengan Proses Hidrolisis Asam Dan Fermentasi

Bioethanol is an alternative fuel made from biomass containing sugar components, starch, and cellulose. So far, bioethanol is made from raw materials which become a source of food and feed resulting in the competition. The potential of cellulosic biomass seaweed S. duplicatum as bioethanol production can be a solution to resolve the issue. The purpose of this research was to study seaweed S. duplicatum J.G. Agardh as raw material for bioethanol. Method used for this research was experimental laboratory with a completely randomized design (RAL) factorial pattern to test glucose levels and a randomized block design (RAK) to test the ethanol levels. Ethanol concentration was determined by Gas Chromatography (GC). Hydrolysis with H2SO4 concentration of 0.2 M, 0.3 M, 0.4 M, 0.5 M and the variation within 30 minutes, 60 minutes, 120 minutes. The fermentation conducted with yeast S. cereviceae with incubation time 24 hours, 48 hours, 72 hours. Ethanol concentration measurements conducted using Gas Chromatography (GC). The results showed that the best conditions for hydrolysis of concentrated H2SO4 0.4 M (28.051 mg / ml ± 1.100) and 120 minutes (23.128 mg / ml ± 6.069). During the fermentation process, the maximum ethanol levels achieved at 72 hours incubation time is 0.0451% v / v ± 0.009

High-order optical nonlinearity at low light levels

We observe a nonlinear optical process in a gas of cold atoms that simultaneously displays the largest reported fifth-order nonlinear susceptibility \chi^(5) = 1.9x10^{-12} (m/V)^4 and high transparency. The nonlinearity results from the simultaneous cooling and crystallization of the gas, and gives rise to efficient Bragg scattering in the form of six-wave-mixing at low-light-levels. For large atom-photon coupling strengths, the back-action of the scattered fields influences the light-matter dynamics. This system may have important applications in many-body physics, quantum information processing, and multidimensional soliton formation.Comment: 5 pages, 3 figure