Uniform decision problems in automatic semigroups

We consider various decision problems for automatic semigroups, which involve the provision of an automatic structure as part of the problem instance. With mild restrictions on the automatic structure, which seem to be necessary to make the problem well-defined, the uniform word problem for semigroups described by automatic structures is decidable. Under the same conditions, we show that one can also decide whether the semigroup is completely simple or completely zero-simple; in the case that it is, one can compute a Rees matrix representation for the semigroup, in the form of a Rees matrix together with an automatic structure for its maximal subgroup. On the other hand, we show that it is undecidable in general whether a given element of a given automatic monoid has a right inverse.Comment: 19 page

Decidability Results for the Boundedness Problem

We prove decidability of the boundedness problem for monadic least fixed-point recursion based on positive monadic second-order (MSO) formulae over trees. Given an MSO-formula phi(X,x) that is positive in X, it is decidable whether the fixed-point recursion based on phi is spurious over the class of all trees in the sense that there is some uniform finite bound for the number of iterations phi takes to reach its least fixed point, uniformly across all trees. We also identify the exact complexity of this problem. The proof uses automata-theoretic techniques. This key result extends, by means of model-theoretic interpretations, to show decidability of the boundedness problem for MSO and guarded second-order logic (GSO) over the classes of structures of fixed finite tree-width. Further model-theoretic transfer arguments allow us to derive major known decidability results for boundedness for fragments of first-order logic as well as new ones

Analysis of Energy Supply and Usage in the Iowa Economy

This report addresses the needs of state policymakers to understand the implications to the state’s economy from current levels of energy supply imports. Historical energy consumption patterns for the state and the role of energy in the performance of the Iowa economy are reviewed using current data. Economic modeling techniques are then used to analyze the linkages of these energy sectors, forward and backwards, with the rest of the economy. Information on the importance of energy to various economic activities and the share of energy expenditure that goes to in-state vs. out-of-state sources, including the energy distribution functions, is also provided. The objective of this report is to review the information on the quantities of energy consumed and dollars spent in Iowa and evaluate the share of these energy dollars that are leaving the state.

A Preliminary Investigation of School District Expenditures with Respect to School District Size in Iowa

This is a preliminary investigation into the relationships between public school district size and patterns in school district expenditures and revenues in Iowa.  The report uses Internet-accessible revenue and expenditure data to examine the relative importance of primary education to the Iowa’s budget and to local government budgets.  Data derived from the Certified Annual Report that each public school district files with the Iowa Department of Education are used to examine patterns of revenues and expenditures for all Iowa public school districts relative to school district sizes and state averages.  The analysis finds a reciprocal relationship between total district expenditures per student and district size.  Economy of scale is a substantial factor as district enrollments decline below 750 students.

Preliminary Market and Cost Analysis of a Five-Station Hemodialysis Facility in Marengo, Iowa

This report was commissioned by the Marengo Memorial Hospital to evaluate the market potential for a new kidney dialysis facility. Marengo Memorial Hospital is a rural hospital located in Marengo, a town of 2,535 people in north central Iowa County, Iowa (see the star in Map 1). In 2001, the hospital reported a capacity of 25 acute-care beds, 228 admissions, 8,485 inpatient admission days, and 8,750 outpatient visits. Marengo Memorial Hospital intends to add space in order to expand its wellness, health maintenance, and community programs. One of the options for use of this added space is a fivestation hemodialysis facility. Our primary goal is to determine whether there is enough current and anticipated demand for in-center hemodialysis services within the immediate area and surrounding region to support such a facility. Our secondary aim is to determine the utilization levels at which a five-station hemodialysis facility's operations can be self-financed. For the purposes of this report, it is assumed that suitable facility space will be included in hospital expansion, regardless of whether the space is utilized for dialysis operations. This report focuses on the potential market for and operational costs and revenues associated with the proposed dialysis facility.

High-order cyclo-difference techniques: An alternative to finite differences

The summation-by-parts energy norm is used to establish a new class of high-order finite-difference techniques referred to here as 'cyclo-difference' techniques. These techniques are constructed cyclically from stable subelements, and require no numerical boundary conditions; when coupled with the simultaneous approximation term (SAT) boundary treatment, they are time asymptotically stable for an arbitrary hyperbolic system. These techniques are similar to spectral element techniques and are ideally suited for parallel implementation, but do not require special collocation points or orthogonal basis functions. The principal focus is on methods of sixth-order formal accuracy or less; however, these methods could be extended in principle to any arbitrary order of accuracy

A Producer's Propensity to Conserve Framework: Application to a US and Australian Conservation Program

Increasing recognition of the environmental impact of agriculture has led to increasing public activity around the world encouraging public conservation programs. Different countries have taken different program approaches to accomplish this. The comparison and contrast here is between Australia and the United States, examining the CREP program in the U.S. and the Eco Tender program in Australia. A different historical experience in the U.S. sets certain parameters that are expected in their conservation programs. To some extent, the Australian program could take more of a clean slate approach. The Australian program is able to take a broader landscape approach, specifically considering multiple benefits with knowledge about off-site benefits as well. This is tied into a structured auction process that does not allow gaming of the auction process. While the U.S. approach does include a bidding process, its structure is such that it has characteristics of an incentive program. The U.S. approach also gives less incentive to farmers to provide environmental amenities at the lowest possible cost. Taking off-site impacts into consideration and finding ways to induce competition among farmers to provide amenities at the lowest cost to the public are seen as important characteristics of cost effective conservation programs.Resource /Energy Economics and Policy,

Preliminary Investigations of Hospital Geography and Patient Choice in Iowa

This report provides a spatial representation of hospital geography in Iowa and of the decisions of patients to patronize hospitals. It begins with a brief analysis of hospital proximity and hospital proximity’s relationship to population distributions and existing hospital capacity.  This is followed with a discussion of hospital capacity as a proxy for the supply of hospital services and the construction of hospital service area gravity models based upon capacity.   Patient patronage of hospitals is then presented as a proxy of demand for hospital services, and gravity models are estimated on the basis of patronage. healthcare; hospital

Solving the Jitter Problem in Microwave Compressed Ultrafast Electron Diffraction Instruments: Robust Sub-50 fs Cavity-Laser Phase Stabilization

We demonstrate the compression of electron pulses in a high-brightness ultrafast electron diffraction (UED) instrument using phase-locked microwave signals directly generated from a mode-locked femtosecond oscillator. Additionally, a continuous-wave phase stabilization system that accurately corrects for phase fluctuations arising in the compression cavity from both power amplification and thermal drift induced detuning was designed and implemented. An improvement in the microwave timing stability from 100 fs to 5 fs RMS is measured electronically and the long-term arrival time stability ($>$10 hours) of the electron pulses improves to below our measurement resolution of 50 fs. These results demonstrate sub-relativistic ultrafast electron diffraction with compressed pulses that is no longer limited by laser-microwave synchronization.Comment: Accepted for publication in Structural Dynamic

Cross-Boundary Weed Management in Protected Area-Centered Ecosystems: How Can it Work and What Makes it Harder to Achieve?

Invasive species management in natural landscapes is generally executed at the scale of independent jurisdictions, yet the ecological processes and biodiversity to be protected from invasion occur over large spatial scales and across multiple jurisdictions. Jurisdictional land boundaries can influence the flows and dynamics of ecological systems, as well as the social systems that exist in these complex landscapes. Land management entities in large, protected area-centered ecosystems may use different approaches to address cross-boundary management challenges. To understand these differing strategies and their effects on cooperative invasive plant management, we interviewed employees with federal, county and state agencies, research organizations, nonprofits, and local stakeholder groups in two national parks and their surrounding lands in California, USA. Although all participants stressed the importance of working together, they did so along a continuum of strategies ranging from simple communication to coordination of independent efforts to active collaboration. Barriers to collaboration can be categorized as originating within or externally to the management unit, including limited resources, differing agency priorities, paperwork requirements, and lack of support by higher-level managers. Strategies to reduce barriers depend on where they originate