Legendrian singular links and singular connected sums

We study Legendrian singular links up to contact isotopy. Using a special property of the singular points, we define the singular connected sum of Legendrian singular links. This concept is a generalization of the connected sum and can be interpreted as a tangle replacement, which provides a way to classify Legendrian singular links. Moreover, we investigate several phenomena only occur in the Legendrian setup

Why your neighbor matters: Positions in preferential trade agreement networks and export growth in global value chains

In rapidly expanding global and regional preferential trade agreements (PTA) networks, policy‐makers are keen to situate their countries in a better position, believing that a better position in PTA networks will help their economies trade more and grow faster. In this paper, we provide a theory that explains how changes in countries’ PTA network positions affect their trade performance. We argue that a dense and deep “neighbor network” provides a country with a wide access to global value chains, better protection to investment, and strong credibility to their policy commitments. To measure trade performance, we compute value‐added exports at the country, year, and industry level across 43 countries, 56 industries, and 15 years (2000–14). The estimation of network position effects is done by panel fixed‐effects methods and the sample‐splitting and cross‐fitting double machine‐learning method. The findings show that as a country’s neighbors have deeper and wider PTA networks, the country’s value‐added exports grow faster. Also, the industry‐level analysis shows that sectors heavily engaging in the fragmentation of production stages exhibit faster growth with the improvement of neighbor networks.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163429/2/ecpo12152.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163429/1/ecpo12152_am.pd

Algae–bacteria interactions: Evolution, ecology and emerging applications

AbstractAlgae and bacteria have coexisted ever since the early stages of evolution. This coevolution has revolutionized life on earth in many aspects. Algae and bacteria together influence ecosystems as varied as deep seas to lichens and represent all conceivable modes of interactions — from mutualism to parasitism. Several studies have shown that algae and bacteria synergistically affect each other's physiology and metabolism, a classic case being algae–roseobacter interaction. These interactions are ubiquitous and define the primary productivity in most ecosystems. In recent years, algae have received much attention for industrial exploitation but their interaction with bacteria is often considered a contamination during commercialization. A few recent studies have shown that bacteria not only enhance algal growth but also help in flocculation, both essential processes in algal biotechnology. Hence, there is a need to understand these interactions from an evolutionary and ecological standpoint, and integrate this understanding for industrial use. Here we reflect on the diversity of such relationships and their associated mechanisms, as well as the habitats that they mutually influence. This review also outlines the role of these interactions in key evolutionary events such as endosymbiosis, besides their ecological role in biogeochemical cycles. Finally, we focus on extending such studies on algal–bacterial interactions to various environmental and bio-technological applications

Comparison of Sasang Constitutional Medicine, Traditional Chinese Medicine and Ayurveda

Sasang constitutional medicine (SCM), traditional Chinese medicine (TCM) and Ayurveda are three different forms of Asian traditional medicine. Although these traditions share a lot in common as holistic medicines, the different philosophical foundations found in each confer distinguishing attributes and unique qualities. SCM is based on a constitution-based approach, and is in this way relatively more similar to the Ayurvedic tradition than to the TCM, although many of the basic SCM theories were originally derived from TCM, a syndrome-based medicine. SCM and TCM use the same botanical materials that are distributed mainly in the East Asian region, but the basic principles of usage and the underlying rationale are completely different from each other. Meanwhile, the principles of the Ayurvedic use of botanical resources are very similar to those seen in SCM, but the medicinal herbs used in Ayurveda generally originate from the West Asian region which displays a different spectrum of flora

Topological Structure of Dense Hadronic Matter

We present a summary of work done on dense hadronic matter, based on the Skyrme model, which provides a unified approach to high density, valid in the large $N_c$ limit. In our picture, dense hadronic matter is described by the {\em classical} soliton configuration with minimum energy for the given baryon number density. By incorporating the meson fluctuations on such ground state we obtain an effective Lagrangian for meson dynamics in a dense medium. Our starting point has been the Skyrme model defined in terms of pions, thereafter we have extended and improved the model by incorporating other degrees of freedom such as dilaton, kaons and vector mesons.Comment: 13 pages, 8 figures, Talk given at the KIAS-APCTP Symposium in Astro-Hadron Physics "Compact Stars: Quest for New States of Dense Matter", November 10-14, 2003, Seoul, Korea, published by World Scientific. Based on talk by B.-Y. Par

One-pot Enzymatic Synthesis of Deoxy-thymidine-diphosphate (TDP)-2-deoxy-∝-d-glucose Using Phosphomannomutase

Production of deoxy-thymidine-diphosphate (TDP)-sugars as substrates of glycosyltransferases, has been one of main hurdles for combinatorial antibiotic biosynthesis, which combines sugar moiety with aglycon of various antibiotics. Here, we report the one-pot enzymatic synthesis of TDP-2-deoxy-glucose employing high efficient TMP kinase (TMK; E.C. 2.7.2.12), acetate kinase (ACK; E.C. 2.7.1.21), and TDP-glucose synthase (TGS; E.C. 2.7.7.24) with phosphomannomutase (PMM; E.C. 5.4.2.8). In this study, replacing phosphoglucomutase (PGM; E.C. 5.4.2) by PMM from Escherichia coli gave four times higher specific activity on 2-deoxy-6-phosphate glucose, suggesting that the activity on 2-deoxy-glucose-6-phosphate was mainly affected by PMM activity, not PGM activity. Using an in vitro system starting from TMP and 2-deoxy-glucose-6-phosphate glucose, TDP-2-deoxy-glucose (63% yield) was successfully synthesized. Considering low productivity of NDP-sugars from cheap starting materials, this paper showed how production of NDP-sugars could be enhanced by controlling mutase activity

An Efficient Building Evacuation Algorithm in Congested Networks

This paper proposes a new network model for the building evacuation problem considering congestion levels and provides a mixed integer linear programming (MILP) model and an efficient heuristic algorithm solving the problem. Constructing an optimization model with several congestion levels, we introduce a new network called the multi-class time-expanded (MCTE) network having several exclusive arcs connecting the same tail and head nodes. The MCTE networks make both the MILP model and the heuristic algorithm reflect a realistic situation in congested networks. Considering MCTE networks makes the problem difficult to solve, which motivates us to develop an efficient heuristic algorithm. We test our heuristic algorithm using several real-world networks such as a multiplex cinema, a subway station, and a large-size complex shopping mall in addition to an artificial network for clear comparison between the proposed algorithm and the MILP approaches. The results indicate that the proposed algorithm runs fast and produces a near-optimal solution compared with those from MILP models with a commercial solver.11Ysciescopu