Braids, mapping class groups, and categorical delooping

Dehn twists around simple closed curves in oriented surfaces satisfy the braid relations. This gives rise to a group theoretic from the braid group to the mapping class group. We prove here that this map is trivial in stable homology with any trivial coefficients. In particular this proves an old conjecture of J. Harer. The main tool is categorical delooping. In an appendix we discuss geometrically defined homomorphisms from the braid to the mapping class group.Comment: 19 pages, 9 figures, late

EXPLORING THE LINKAGES BETWEEN FIRM INTERACTIVITY, INNOVATION, AND IMPROVED BUSINESS PERFORMANCE

In today’s dynamic and hypercompetitive business environment, knowledge and innovation have emerged as bases for sustained competitive advantage. This paper addresses two specific research questions. First, we ask, “What is the effect that firm interactivity has on various types of innovation?” As we address this question, we explain that interactivity helps firms create knowledge, which then promotes and enables innovation. Second, we ask, “How do the various types of innovation impact firm performance?” We develop a research model and a set of hypotheses from the basis of organizational knowledge creation theory and the knowledge-based view of the firm. We test this model using survey data, and find that interactivity is positively associated with innovation. We also find that several types of innovation, including service innovation, process innovation, and organizational innovation have a positive impact on firm performance

Related-Key Boomerang Attack on Block Cipher SQUARE

Square is 8-round SPN structure block cipher and its round function and key schedule have been slightly modified to design building blocks of Rijndael. Key schedule of Square is simple and efficient but fully affie, so we apply a related-key attack on it. We find a 3-round related-key differential trail with probability 2^28, which have zero differences both on its input and output states, and this trail is called the local collision in [5]. By extending of this related-key differential, we construct a 7-round related-key boomerang distinguisher and successful attack on full round Square. The best attack on Square have ever been known is the square attack on 6-round reduced variant of Square. In this paper, we present a key recovery attack on the full round of Square using a related-key boomerang distinguisher. We construct a 7-round related-key boomerang distinguisher with probability 2^119 by finding local collision, and calculate its probability using ladder switch and local amplification techniques. As a result, one round on top of distinguisher is added to construct a full round attack on Square which recovers 16-bit key information with 2^36 encryptions and 2^123 data

Effects of Condylar Elastic Properties to Temporomandibular Joint Stress

Mandibular condyle plays an important role in the growth and reconstruction of the temporomandibular joint (TMJ). We aimed to obtain orthotropic elastic parameters of the condyle using a continuous-wave ultrasonic technique and to observe the effects of condylar elastic parameters on stress distribution of the TMJ using finite element analysis (FEA). Using the ultrasonic technique, all nine elastic parameters were obtained, which showed that the mandibular condyle was orthotropic. With the condyle defined as orthotropic, the occlusal stress was transferred fluently and uniformly from the mandible to the TMJ. The stress distribution in the isotropic model showed stepped variation among different anatomical structures with higher stress values in the cartilage and condyle than in the orthotropic model. We conclude that anisotropy has subtle yet significant effects on stress distribution of the TMJ and could improve the reality of simulations

Variation of Tensor Force due to Nuclear Medium Effect

The enhancement of $J^{\pi}(T)$=3$^{+}$(0) state with isospin $T=0$ excited by the tensor force in the free $^{6}$Li nucleus has been observed, for the first time, relative to a shrinkable excitation in the $^{6}$Li cluster component inside its host nucleus. Comparatively, the excitation of $J^{\pi}(T)$=0$^{+}$(1) state with isospin $T=1$ for these two $^{6}$Li formations take on an approximately equal excitation strength. The mechanism of such tensor force effect was proposed due to the intensive nuclear medium role on isospin $T$=0 state.Comment: 6 pages, 4 figure

Aspect of Clusters Correlation at Light Nuclei Excited State

The correlation of $\alpha\alpha$ was probed via measuring the transverse momentum $p_{T}$ and width $\delta p_{T}$ of one $\alpha$, for the first time, which represents the spatial and dynamical essentialities of the initial coupling state in $^{8}$Be nucleus. The weighted interaction vertex of 3$\alpha$ reflected by the magnitudes of their relative momentums and relative emission angles proves the isosceles triangle configuration for 3$\alpha$ at the high excited energy analogous Hoyle states.Comment: 8 pages, 9 figure