Generalized Skein Modules of Surfaces

Frobenius extensions play a central role in the link homology theories based upon the sl(n) link variants, and each of these Frobenius extensions may be recast geometrically via a category of marked cobordisms in the manner of Bar-Natan. Here we explore a large family of such marked cobordism categories that are relevant to generalized sl(n) link homology theories. We also investigate the skein modules that result from embedding these marked cobordisms within 3-manifolds, and arrive at an explicit presentation for several of these generalized skein modules.Comment: 23 pages, multiple figure

Strong Szego asymptotics and zeros of the zeta function

Assuming the Riemann hypothesis, we prove the weak convergence of linear statistics of the zeros of L-functions towards a Gaussian field, with covariance structure corresponding to the \HH^{1/2}-norm of the test functions. For this purpose, we obtain an approximate form of the explicit formula, relying on Selberg's smoothed expression for $\zeta'/\zeta$ and the Helffer-Sj\"ostrand functional calculus. Our main result is an analogue of the strong Szeg{\H o} theorem, known for Toeplitz operators and random matrix theory

Time to Talk? How the Structure of Dialog Processes Shapes Stakeholder Learning in Participatory Water Resources Management

Public participation is increasingly viewed as a means to initiate social learning among stakeholders, resource managers, and policy makers rather than to ensure democratic representation. This growing understanding of participatory activities as learning platforms can be seen as a direct response to shifts in how natural resources management is framed, namely as uncertain, non-linear, and interlinked with the human dimensions. Social learning as it is discussed within the natural resources management (NRM) context features a process of collective and communicative learning that is thought to enable stakeholders to arrive at a shared understanding of a specific environmental situation and to develop new solutions as well as ways of acting together in pursuit of a shared ambition. Yet, although case-study research on social-learning processes provides multiple accounts of positive experiences, there are also reports of mistaken learning, the intensification of tensions or conflict, and failure to reach agreement or verifiable consensus. Based on results of a postal survey of stakeholder experiences in two involvement initiatives, we can draw two main conclusions: First, social learning is a multidimensional and dynamic process and, as such, evolves in stages and to various degrees. Second, stakeholder processes are shaped and affected by a multitude of factors that constrain the occurrence of learning processes and eventually limit the extent to which these can contribute to sustainable NRM. Foremost, the fact that the intensity of stakeholder learning differed in the two investigated initiatives reinforces the role organizational arrangements play in encouraging the type of communicative process necessary for stakeholder learning

Unauthorized Immigrants and Their U.S.-Born Children

Analyzes data on the number, age distribution, fertility, and family structure of legal and unauthorized immigrants and the percentage of their children among all U.S. children and of the U.S.-born and foreign-born among their children

Non-Hermitian topology of spontaneous magnon decay

Spontaneous magnon decay is a generic feature of the magnetic excitations of anisotropic magnets and isotropic magnets with non-collinear order. In this paper, we argue that the effect of interactions on one-magnon states can, under many circumstances, be treated in terms of an effective, energy independent, non-Hermitian Hamiltonian for the magnons. In the vicinity of Dirac or Weyl touching points, we show that the spectral function has a characteristic anisotropy arising from topologically protected exceptional points or lines in the non-Hermitian spectrum. Such features can, in principle, be detected using inelastic neutron scattering or other spectroscopic probes. We illustrate this physics through a concrete example: a honeycomb ferromagnet with Dzyaloshinskii-Moriya exchange. We perform interacting spin wave calculations of the structure factor and spectral function of this model, showing good agreement with results from a simple effective non-Hermitian model for the splitting of the Dirac point. Finally, we argue that the zoo of known topological protected magnon band structures may serve as a nearly ideal platform for realizing and exploring non-Hermitian physics in solid-state systems.Comment: 4+epsilon page

Animation graphic interface for the space shuttle onboard computer

Graphics interfaces designed to operate on space qualified hardware challenge software designers to display complex information under processing power and physical size constraints. Under contract to Johnson Space Center, MICROEXPERT Systems is currently constructing an intelligent interface for the LASER DOCKING SENSOR (LDS) flight experiment. Part of this interface is a graphic animation display for Rendezvous and Proximity Operations. The displays have been designed in consultation with Shuttle astronauts. The displays show multiple views of a satellite relative to the shuttle, coupled with numeric attitude information. The graphics are generated using position data received by the Shuttle Payload and General Support Computer (PGSC) from the Laser Docking Sensor. Some of the design considerations include crew member preferences in graphic data representation, single versus multiple window displays, mission tailoring of graphic displays, realistic 3D images versus generic icon representations of real objects, the physical relationship of the observers to the graphic display, how numeric or textual information should interface with graphic data, in what frame of reference objects should be portrayed, recognizing conditions of display information-overload, and screen format and placement consistency

Planning Rural Water Services in Nicaragua: A Systems-Based Analysis of Impact Factors Using Graphical Modeling

The success or failure of rural water services in the developing world is a result of numerous factors that interact in a complex set of connections that are difficult to separate and identify. This research effort presented a novel means to empirically reveal the systemic interactions of factors that influence rural water service sustainability in the municipalities of Darío and Terrabona, Nicaragua. To accomplish this, the study employed graphical modeling to build and analyze factor networks. Influential factors were first identified by qualitatively and quantitatively analyzing transcribed interviews from community water committee members. Factor influences were then inferred by graphical modeling to create factor network diagrams that revealed the direct and indirect interaction of factors. Finally, network analysis measures were used to identify “impact factors” based on their relative influence within each factor network. Findings from this study elucidated the systematic nature of such factor interactions in both Darío and Terrabona, and highlighted key areas for programmatic impact on water service sustainability for both municipalities. Specifically, in Darío, the impact areas related to the current importance of water service management by community water committees, while in Terrabona, the impact areas related to the current importance of finances, viable water sources, and community capacity building by external support. Overall, this study presents a rigorous and useful means to identify impact factors as a way to facilitate the thoughtful planning and evaluation of sustainable rural water services in Nicaragua and beyond