Playing Stackelberg Opinion Optimization with Randomized Algorithms for Combinatorial Strategies

From a perspective of designing or engineering for opinion formation games in social networks, the "opinion maximization (or minimization)" problem has been studied mainly for designing subset selecting algorithms. We furthermore define a two-player zero-sum Stackelberg game of competitive opinion optimization by letting the player under study as the first-mover minimize the sum of expressed opinions by doing so-called "internal opinion design", knowing that the other adversarial player as the follower is to maximize the same objective by also conducting her own internal opinion design. We propose for the min player to play the "follow-the-perturbed-leader" algorithm in such Stackelberg game, obtaining losses depending on the other adversarial player's play. Since our strategy of subset selection is combinatorial in nature, the probabilities in a distribution over all the strategies would be too many to be enumerated one by one. Thus, we design a randomized algorithm to produce a (randomized) pure strategy. We show that the strategy output by the randomized algorithm for the min player is essentially an approximate equilibrium strategy against the other adversarial player

Easy-Fit Triathlon Racing Shoe

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes bibliographical references (p. 30).Triathlon is one of the fastest growing sports in the world. The swim-bike-run competition has opened a whole new market in the industry of athletic footwear. In a triathlon, athletes need to make fast transitions from the swim to the bike, then from the bike to the run. Therefore, there is a demand for a triathlon running shoe that is easy and quick to slip on. In this project, the upper portion of a new racing shoe is developed, called the Easy-Fit Triathlon Shoe. It is specially designed with an incredible ease of entry to minimize transition time. A worldwide survey was conducted, and it was found that racing shoe performance features, such as being lightweight and having adequate cushioning, are extremely important to the elite competitive triathlete. Therefore, these features were also integrated into the design of the Easy-Fit Triathlon Shoe. The innovative tongue and heel system expand the shoe opening then tighten the entire shoe efficiently. Collaborative work was done with New Balance, and a prototype was built.by Chi-An Wang.S.B

Export Outsourcing and Foreign Direct Investment: Evidence from Taiwanese Exporting Firms

Exporting and FDI have traditionally been two major firm-level responses to globalization. Export outsourcing (EO), a new strategy that gained in importance recently, has now become another alternative. This paper seeks to examine how firms choose between EO and outward FDI by looking into firm-level productivity differences. A special data set is constructed by consolidating two micro data sets of Taiwanese manufacturing firms. The paper contributes in four main ways. First, it provides a causality analysis of labor productivity and EO, whereas previous studies deal only with correlations. Second, it shows that EO can be interpreted as an indirect way of exporting. Third, it points out that outward FDI itself may not help with productivity if it is not linked with EO, which finding contradicts conventional wisdom. Finally, most evidences seem to imply that the intricate Taiwan-China interconnection is a significant factor that facilitates or contributes to all above-mentioned findings.productivity, exports, foreign outsourcing, FDI, firm-level data

Effects of metformin on human monocytic THP-1 cells - Implications for type 2 diabetes mellitus

Metformin is an anti-hyperglycaemic agent widely prescribed for type 2 diabetes (T2D). Despite decades of clinical use, its exact pharmacological mechanism(s) is yet to be definitively determined. Accumulative data have shown its mild inhibitory effect on the complex 1 of the mitochondrial respiratory chain, which is thought to contribute to its anti-hyperglycaemic effect. Metformin is also thought to have a protective effect on cardiovascular disease (CVD), the most common complication in T2D. It is widely accepted that T2D is an inflammatory state thus it is not surprising that T2D patients have 2-4 times higher risk in developing CVD. Furthermore, the pathology of T2D has been proposed to involve dysfunctioning mitochondria, the organelle of energy sensing and production. The use of metformin, a mitochondria inhibitor, in cells under mitochondrial stress led us to speculate the physiological responses that ensue. To understand metformin‟s mode of action and its involvement in inflammation processes the human monocytic leukemia THP-1 cells were used in this study. Since studies of metformin on this cell type is scarce if not non-existence the first task was to determine its cytoxicity in this cell line. Next the mRNA and protein expressions of heat shock protein 60 (Hsp60), a mitochondrial stress marker, was determined in metformin-treated THP-1 cells. Further, various cell types have shown surface expressed Hsp60 under stress conditions. Thus the study here attempted to optimise the detection of surface Hsp60 in THP-1 cells, as human Hsp60 has been shown to induce innate immune response. Localisation of Hsp60 on the cell surface in metformin-treated cells may exacerbate the already-inflammed state of T2D. Lastly, metformin‟s effect on PMA-stimulated monocyte differentiation was determined by the mRNA expression of CD14, a surface receptor on macrophages. The results here agreed with published data that metformin at therapeutic concentrations are not cytotoxic and is a mild inhibitor of mitochondrial respiration. We also provide evidence that metformin up-regulated the mitochondria stress protein, Hsp60, in a time- and dose-dependent manner. In addition, live cell Hsp60 immunocytochemistry proved to be a promising method for surface Hsp60 detection in THP-1 cells. Finally, at the therapeutic concentration metformin caused a significant up-regulation in cd14 expression, which contradicts with much acclaimed protective effect of metformin in the literature

Distribution of Enterotoxigenic Clostridium perfringens Spores in U.S. Retail Spices

246 samples of bulk and packaged spices from retail stores in the western, southeastern, southern, midwestern, and northeastern areas of the U.S. were examined for the presence of Clostridium -perfringens. Isolates were checked for the presence of the lecithinase gene (cpa) and enterotoxin genes (cpe) by PCR. Enterotoxin formation during sporulation was investigated using the Oxoid Toxin Detection Kit. Forty-three confirmed isolates (from 17% of total samples) were cpa-positive. Of those, 27 were cpe-positive. Together, levels of C. perfringens spores ranged from 3.6-2400/gm. The amount of enterotoxin in cell extracts ranged from 2-16 ng/ml. Some of the SEM images of isolated spore (# 78) and one plasmid-borne ent control (FD-153) showed an organized surface structure termed “candy-wrapper”. This extracellular structure remained after treatment with 0.1 % SDS for 1 hr, suggesting it was not composed of membrane debris from the mother cell. The D values of spores ranged from 1.19- 3.31 min. The addition of lysozyme in the plating medium elevated the recovery rate of heat-treated spores. The growth rate of a cocktail of spores from spices (# 31, # 32, # 45) between 4 to 5 hr after inoculation was determined with a doubling time of 6.82 min in hamburger. A cocktail of spores of plasmid-borne ent control showed an optimum growth rate between 5 to 8 hr after inoculation with doubling time of 15.98 min. However; spice isolate cocktail, plasmid-borne ent control cocktail (FD-5603 and FD-153), and a chromosome-borne ent control (NTCT 8239) were unable to germinate and outgrowth at 20oC. Inoculation in laboratory medium FTG indicated the same result as hamburger at 20oC. The ability of C. perfringens spores in spices to potentially survive cooking procedures can be followed by germination and growth of vegetative cells during improper cooling to levels associated with foodborne illness caused by this organism. Our results suggest that retail spices are potential vehicles of transmission of enterotoxin-positive C. perfringens