A Riemann-Roch theorem for edge-weighted graphs

We prove a Riemann-Roch theorem for real divisors on edge-weighted graphs over the reals, extending the result of Baker and Norine for integral divisors on graphs with multiple edges.Comment: Minor revisions, 10 page

Riemann-Roch theory on finite sets

In [1] M. Baker and S. Norine developed a theory of divisors and linear systems on graphs, and proved a Riemann-Roch Theorem for these objects (conceived as integer-valued functions on the vertices). In [2] and [3] the authors generalized these concepts to real-valued functions, and proved a corresponding Riemann-Roch Theorem in that setting, showing that it implied the Baker-Norine result. In this article we prove a Riemann-Roch Theorem in a more general combinatorial setting that is not necessarily driven by the existence of a graph.Comment: 7 pages, 4 figure

Organisational Challenges Facing Civil Society Networks in Malawi

The research results provide a snapshot of civil society networks in Malawi today, whilst highlighting the critical organisational challenges in 2006. The project did not aim for nor did it achieve an exhaustive impact assessment of all civil society networks in the country. Interviews focussed on three networks: Malawi Economic Justice Network (MEJN), Land Task Force (LTF) and Civil Society Coalition on Basic Quality Education (CSCQBE). The findings therefore directly relate to thesethree networks; although they have resonance with other civil society networks in Malawi and globally.The main elements of the research methodology included: Literature review to provide an overview of current thinking (see references);Semi-structured interviews with up to 25 stakeholders for Malawi Economic Justice Network (MEJN), Civil Society Coalition for Quality Basic Education (CSCQBE), Land Task Force (LTF), other CSO networks, donors, and government;Analysis of consultancy work with MEJN and Civil Society Agriculture Network (CISANET);Analysis and write up;Publication and dissemination.The paper will briefly discuss the development impact of the CSOs before proceeding to discuss the critical organisational capacity issues facing the networks

The U.S. Gulf of Mexico Pink Shrimp, Farfantepenaeus duorarum, Fishery: 50 Years of Commercial Catch Statistics

U.S. Gulf of Mexico, pink shrimp, Farfantepenaeus duorarum, catch statistics have been collected by NOAA’s National Marine Fisheries Service, or its predecessor agency, for over 50 years. Recent events, including hurricanes and oil spills within the ecosystem of the fishery, have shown that documentation of these catch data is of primary importance. Fishing effort for this stock has fluctuated over the 50-year period analyzed, ranging from 3,376 to 31,900 days fished, with the most recent years on record, 2008 and 2009, exhibiting declines up to 90% relative to the high levels recorded in the mid 1990’s. Our quantification of F. duorarum landings and catch rates (CPUE) indicates catch have been below the long-term average of about 12 million lb for all of the last 10 years on record. In contrast to catch and effort, catch rates have increased in recent years, with record CPUE levels measured in 2008 and 2009, of 1,340 and 1,144 lb per day fished, respectively. Our regression results revealed catch was dependent upon fishing effort (F=98.48df=1, 48, p<0.001, r2=0.67), (Catch=1,623,378 + (520) × (effort)). High CPUE’s measured indicate stocks were not in decline prior to 2009, despite the decline in catch. The decrease in catch is attributed in large part to low effort levels caused by economical and not biological or habitat related conditions. Future stock assessments using these baseline data will provide further insights and management advice concerning the Gulf of Mexi

Distribution of Bats in the Delta Region of Northeastern Arkansas

Eight taxa of bats are reported from seven counties in northeastern Arkansas. Localities, natural history notes, sex, age and reproductive condition are reported for most species. New records are combined with previously existing ones to reveal a greater distribution of chiroptera for the stat

How well do we need to measure Higgs boson couplings?

Most of the discussion regarding the Higgs boson couplings to Standard Model vector bosons and fermions is presented with respect to what present and future collider detectors will be able to measure. Here, we ask the more physics-based question of how well do we need to measure the Higgs boson couplings? We first present a reasonable definition of "need" and then investigate the answer in the context of various highly motivated new physics scenarios: supersymmetry, mixed-in hidden sector Higgs bosons, and a composite Higgs boson. We find the largest coupling deviations away from the SM Higgs couplings that are possible if no other state related to EWSB is directly accessible at the LHC. Depending on the physics scenario under consideration, we find targets that range from less than 1% to 10% for vector bosons, and from a few percent to tens of percent for couplings to fermions.Comment: 9 pages, 10 figures; v3: minor corrections, to be published in Physical Review

How well do we need to measure the Higgs boson mass and self-coupling?

Much of the discussion regarding future measurements of the Higgs boson mass and self-coupling is focussed on how well various collider options can do. In this article we ask a physics-based question of how well do we need colliders to measure these quantities to have an impact on discovery of new physics or an impact in how we understand the role of the Higgs boson in nature. We address the question within the framework of the Standard Model and various beyond the Standard Model scenarios, including supersymmetry and theories of composite Higgs bosons. We conclude that the LHC's stated ability to measure the Higgs boson to better than 150 MeV will be as good as we will ever need to know the Higgs boson mass in the foreseeable future. On the other hand, we estimate that the self-coupling will likely need to be measured to better than 20 percent to see a deviation from the Standard Model expectation. This is a challenging target for future collider and upgrade scenarios.Comment: 20 pages, 4 figure

A Survey of the Causes for Suspensions in the Junior High Schools of the Highline School District

This study was undertaken to (1) relate compulsory attendance to the problem of suspension, (2) survey the frequency of and causes for suspensions of junior high school students, (3) survey the course of action taken by the school, school district and/or the parents of the suspended student, and (4) to study the number of cases in which pupils were affected by multiple suspensions