Hyperbanana Graphs

A bar-and-joint framework is a finite set of points together with specified distances between selected pairs. In rigidity theory we seek to understand when the remaining pairwise distances are also fixed. If there exists a pair of points which move relative to one another while maintaining the given distance constraints, the framework is flexible; otherwise, it is rigid. Counting conditions due to Maxwell give a necessary combinatorial criterion for generic minimal bar-and-joint rigidity in all dimensions. Laman showed that these conditions are also sufficient for frameworks in R^2. However, the flexible "double banana" shows that Maxwell's conditions are not sufficient to guarantee rigidity in R^3. We present a generalization of the double banana to a family of hyperbananas. In dimensions 3 and higher, these are (infinitesimally) flexible, providing counterexamples to the natural generalization of Laman's theorem

Watching gene expression in color.

A combination of two fluorescent proteins with different half-lives allows gene expression to be followed with improved time resolution

Crayfish and Bivalve Distribution in a Valley in Southwestern Ohio

Author Institution: Department of Zoology, The Ohio State UniversityThe crayfish and bivalve fauna of 2 stream systems in an ancient valley in southwestern Ohio were examined. The distribution of the various species was mapped and the topography and environmental conditions of each collecting site were noted. The greatest diversity of species was usually found at the edge of the valley, while environmentally stressed sites harbored neither decapods nor bivalves. One species of crayfish, Orconectes sloanii, was found in the northwestern drainage system of the valley, but not in the southeastern drainage system, even though the 2 stream systems were once connected

Growth Rate, Life Span and Molting Cycle of the Crayfish Orconectes Sanborni

Author Institution: The Department of Zoology, The Ohio State UniversityOrconectes sanborni young were found to hatch in the spring and to undergo several closely spaced molts. These juveniles could be sexed by mid-summer. A molt occurring in the autumn of the first year was the beginning of a pattern of two molts per year, one in the spring and one in the summer or autumn, although the precise timing of these molts was variable. Both sexes usually reached sexual maturity by the autumn of the second year. At this time the males became form I (breeding) and the oocytes in the females began to increase in size. The maximum life span was found to be thirty-seven months

Fabianism versus welfareism : the movement towards the welfare state in the United States

Finally in the 1880’s there emerged a reformist group which was ultimately to be the model of the viability, adaptability, effectiveness, and success of evolutionary socialism. The group called itself the Fabian Society and in the beginning it seemed to be not unlike other protest or reformist groups which were springing up all over England at the time. The difference was that this group, though always small in numbers, was to have a tremendous impact throughout England and the rest of the democratic world. To be specific, the ideas of the Fabian Socialists can clearly be seen as influencing the movement toward the welfare state in America and this is the main thesis this paper aims to prove - that the ideas and programs of the Fabian Socialists were first implemented in Britain and later in the United State, particularly since the advent of Franklin Delano Roosevelt and his New Deal. It is the author’s contention that these ideas and programs of the Fabians are comparable to a developing movement in the United States toward the welfare state or as others would term it, the good society. This, then, is what the writer seeks to prove

Local P T symmetry violates the no-signaling principle

Bender et al. [Phys. Rev. Lett. 80, 5243 (1998)] have developed PT-symmetric quantum theory as an extension of quantum theory to non-Hermitian Hamiltonians. We show that when this model has a local PT symmetry acting on composite systems, it violates the nonsignaling principle of relativity. Since the case of global PT symmetry is known to reduce to standard quantum mechanics A. Mostafazadeh [J. Math. Phys. 43, 205 (2001)], this shows that the PT-symmetric theory is either a trivial extension or likely false as a fundamental theory. © 2014 American Physical Society

Algorithms for detecting dependencies and rigid subsystems for CAD

Geometric constraint systems underly popular Computer Aided Design soft- ware. Automated approaches for detecting dependencies in a design are critical for developing robust solvers and providing informative user feedback, and we provide algorithms for two types of dependencies. First, we give a pebble game algorithm for detecting generic dependencies. Then, we focus on identifying the "special positions" of a design in which generically independent constraints become dependent. We present combinatorial algorithms for identifying subgraphs associated to factors of a particular polynomial, whose vanishing indicates a special position and resulting dependency. Further factoring in the Grassmann- Cayley algebra may allow a geometric interpretation giving conditions (e.g., "these two lines being parallel cause a dependency") determining the special position.Comment: 37 pages, 14 figures (v2 is an expanded version of an AGD'14 abstract based on v1