Solving Tree Problems with Category Theory

Artificial Intelligence (AI) has long pursued models, theories, and techniques to imbue machines with human-like general intelligence. Yet even the currently predominant data-driven approaches in AI seem to be lacking humans' unique ability to solve wide ranges of problems. This situation begs the question of the existence of principles that underlie general problem-solving capabilities. We approach this question through the mathematical formulation of analogies across different problems and solutions. We focus in particular on problems that could be represented as tree-like structures. Most importantly, we adopt a category-theoretic approach in formalising tree problems as categories, and in proving the existence of equivalences across apparently unrelated problem domains. We prove the existence of a functor between the category of tree problems and the category of solutions. We also provide a weaker version of the functor by quantifying equivalences of problem categories using a metric on tree problems.Comment: 10 pages, 4 figures, International Conference on Artificial General Intelligence (AGI) 201

Reconciling Semiclassical and Bohmian Mechanics: III. Scattering states for continuous potentials

In a previous paper [J. Chem. Phys. 121 4501 (2004)] a unique bipolar decomposition, Psi = Psi1 + Psi2 was presented for stationary bound states Psi of the one-dimensional Schroedinger equation, such that the components Psi1 and Psi2 approach their semiclassical WKB analogs in the large action limit. The corresponding bipolar quantum trajectories, as defined in the usual Bohmian mechanical formulation, are classical-like and well-behaved, even when Psi has many nodes, or is wildly oscillatory. A modification for discontinuous potential stationary stattering states was presented in a second paper [J. Chem. Phys. 124 034115 (2006)], whose generalization for continuous potentials is given here. The result is an exact quantum scattering methodology using classical trajectories. For additional convenience in handling the tunneling case, a constant velocity trajectory version is also developed.Comment: 16 pages and 14 figure

Tenofovir disoproxil fumarate for prevention of HIV infection in women: a phase 2, double-blind, randomized, placebo-controlled trial.

ObjectivesThe objective of this trial was to investigate the safety and preliminary effectiveness of a daily dose of 300 mg of tenofovir disoproxil fumarate (TDF) versus placebo in preventing HIV infection in women.DesignThis was a phase 2, randomized, double-blind, placebo-controlled trial.SettingThe study was conducted between June 2004 and March 2006 in Tema, Ghana; Douala, Cameroon; and Ibadan, Nigeria.ParticipantsWe enrolled 936 HIV-negative women at high risk of HIV infection into this study.InterventionParticipants were randomized 1:1 to once daily use of 300 mg of TDF or placebo.Outcome measuresThe primary safety endpoints were grade 2 or higher serum creatinine elevations (>2.0 mg/dl) for renal function, grade 3 or 4 aspartate aminotransferase or alanine aminotransferase elevations (>170 U/l) for hepatic function, and grade 3 or 4 phosphorus abnormalities (<1.5 mg/dl). The effectiveness endpoint was infection with HIV-1 or HIV-2.ResultsStudy participants contributed 428 person-years of laboratory testing to the primary safety analysis. No significant differences emerged between treatment groups in clinical or laboratory safety outcomes. Study participants contributed 476 person-years of HIV testing to the primary effectiveness analysis, during which time eight seroconversions occurred. Two were diagnosed in participants randomized to TDF (0.86 per 100 person-years) and six in participants receiving placebo (2.48 per 100 person-years), yielding a rate ratio of 0.35 (95% confidence interval = 0.03-1.93), which did not achieve statistical significance. Owing to premature closures of the Cameroon and Nigeria study sites, the planned person-years of follow-up and study power could not be achieved.ConclusionDaily oral use of TDF in HIV-uninfected women was not associated with increased clinical or laboratory adverse events. Effectiveness could not be conclusively evaluated because of the small number of HIV infections observed during the study

Fantasies of subjugation: a discourse theoretical account of British policy on the European Union

The decision by the UK government to hold a referendum on Britain’s membership of the European Union (EU) marks an important development in policy towards the EU. Policy changes of this kind must be understood in the historical and political context in which they occur. This includes the framing of the policy issues within public discourse. In the UK, policies are formed in a discursive environment which is overwhelmingly hostile towards the EU. Debates are structured by a predominantly Euroskeptic discourse which emphasizes the UK’s separation and heterogeneity from the rest of the EU. Drawing on the logics of critical explanation, this article examines the structure and affective power of Euroskeptic discourses which dictate the terms of the EU debate. It presents a case study of the recent EU treaty revision process, culminating in the Treaty of Lisbon. In so doing, it enables a deeper understanding of recent policy developments

Academic Library and Publisher Collaboration: Utilizing an Institutional Repository to Maximize the Visibility and Impact of Articles by University Authors

The George A. Smathers Libraries (Libraries) (http://www.uflib.ufl.edu/) at the University of Florida (UF) (http://www.ufl.edu/) and Elsevier (http://www.elsevier.com) have embarked on a pilot project to maximize visibility, impact, and dissemination of articles by UF researchers who have published in Elsevier journals. Article links and metadata are automatically delivered to UF’s Institutional Repository, the IR@UF (http://ufdc.ufl.edu/ir), in the IR@UF-Elsevier Collection (http://ufdc.ufl.edu/ielsevier). The metadata, with links for approximately 31,000 articles by UF authors, is made possible through integration of the IR@UF with the ScienceDirect application programming interfaces (APIs) (https://www.elsevier.com/solutions/sciencedirect/support/institutional-repository) that are freely available to libraries. Access to the full text on ScienceDirect is available for all institutional repository users affiliated with a subscribing institution. In the next phase users without subscriptions will be able to access the manuscripts of articles published from 2013 forward. This will be done by embedding metadata and links to accepted manuscripts available on ScienceDirect into the IR@UF. We will conduct user and usability testing of this cross-platform user experience. This article provides an overview of the project’s current status, how it works, what it delivers, and next steps expanding the project to include articles by UF authors from other publishers. It concludes with strategic considerations, future developments, and reflections on the value of library/publisher collaboration

Kinematic Age Estimates for 4 Compact Symmetric Objects from the Pearson-Readhead Survey

Based on multi-epoch observations at 15 and 43 GHz with the Very Long Baseline Array (VLBA) we detect significant angular expansions between the two hot spots of 4 Compact Symmetric Objects (CSOs). From these relative motions we derive kinematic ages of between 300 and 1200 years for the radio emission. These ages lend support to the idea that CSOs are produced in a recent phase of activity. These observations also allow us to study the evolution of the hot spots dynamically in individual sources. In all 4 sources the hot spots are separating along the source axis, but in 1031+567 the tip of one hot spot appears to be moving almost orthogonally to the source axis. Jet components, seen in 3 of the 4 sources observed, are found to be moving relativistically outward from the central engines towards the more slowly moving hot spots.Comment: in press at ApJ for v. 541 Oct. 1, 2000, 23 page LaTeX document includes 6 postscript figure

Does preoperative axillary staging lead to overtreatment of women with screen-detected breast cancer?

AIM: To determine the impact of preoperative axillary ultrasound staging in a screen-detected breast cancer population. MATERIALS AND METHODS: Ultrasound and needle biopsy staging results alongside reference standard sentinel lymph node biopsy and axillary lymph node dissection were extracted retrospectively from the unit's computer records between 1 April 2008 and 31 March 2015. Axillary staging was compared with final histopathology and treatment. RESULTS: Of the 215,661 screening examinations performed, 780 invasive cancers were diagnosed, which had preoperative axillary staging data, of which 162 (20.7%) were node positive. Thirty-six (4.6%) had a heavy nodal burden (three or more nodes). Ninety (11.5%) had an abnormal axillary ultrasound and axillary biopsy of which 54 were positive for cancer (33.3% of the node positive cases) and triaged to axillary lymph node dissection avoiding a sentinel lymph node biopsy. Of these 22 (40.7%) had neoadjuvant treatment, and 32 (59.3%) proceeded directly to axillary lymph node dissection. The sensitivity of axillary ultrasound and biopsy to detect women with a heavy nodal burden (three or more nodes) was 41.7% (15 of 36); however, 17 (53%) of the 32 women with a positive axillary biopsy had a low burden of axillary disease (two or fewer positive nodes) at axillary lymph node dissection, the mean number of nodes obtained was 14.6. CONCLUSION: Significant numbers of women are being potentially overtreated or denied entry into positive sentinel node: adjuvant therapy only versus adjuvant therapy and clearance or axillary radiotherapy (POSNOC) because of routine preoperative axillary staging