Potential and historical Uses for bracken (Pteridium aquilinum (L.) Kuhn) in organic agriculture

This report was presented at the UK Organic Research 2002 Conference. Bracken is considered a serious weed species, due to its toxic constituents and negative impacts on agriculture and conservation. Historically however, this fern was a highly prized commodity due to the many uses for cut fronds. Cutting bracken is one of the few bracken management options open to organic farmers. Many traditional uses for the material resulting from harvesting material may have potential in modern organic agriculture, putting a modern value on the plant for its sustainable use or its eradication. This poster reviews some traditional and potential uses within agriculture, investigated as part of a MPhil research project. These uses for bracken include; use as a source of fertility from raw material and ash, weed control for vegetable crops, animal bedding, cover mulch, insect repellent, seed treatment, anti-fungal agent, and biofuel

A formally verified proof of the prime number theorem

The prime number theorem, established by Hadamard and de la Vall'ee Poussin independently in 1896, asserts that the density of primes in the positive integers is asymptotic to 1 / ln x. Whereas their proofs made serious use of the methods of complex analysis, elementary proofs were provided by Selberg and Erd"os in 1948. We describe a formally verified version of Selberg's proof, obtained using the Isabelle proof assistant.Comment: 23 page

Mortality among children and young people who survive cancer in Northern Ireland

ABSTRACT: Whilst survival rates for childhood cancers are excellent, it is known that these patients have an increased risk of death from disease recurrence and other causes. We investigate patterns, trends and survival of cancers in children and young adults in N. Ireland. MATERIALS AND METHODS: 21 years (1993-2013) of cancer incidence data including non-malignant brain tumours from the N. Ireland Cancer Registry for persons aged 0-24 years was analysed using Joinpoint regresssion for trend and the Kaplan Meier method for survival analysis up to end 2013 with excess mortality calculated at one and five years after first cancer diagnosis using standardised mortality ratios. RESULTS: 2633 children and young people were diagnosed with cancer, 1386 (52.6%) male and 1247 female with 1139 (43.3%) aged 0-14. While trends increased over time they did not reach statistical significance except in the 15-24 age group for males and females combined. The most common cancers for age 0-14 were brain, eye and central nervous system and leukaemia with skin (including non-melanoma skin) the most common in the 15-24 age group. 59 patients (2.2%) had a record of a second cancer. Survival was high at 90.7% after 1 year, better among females and similar for older and younger groups. Although mortality in children is low overall, there was an excess mortality 24.7% (22-27.5) p<0.001 at one year and 7.3% (5.5-9.2) p<0.001 for those who survived 5 years. Excluding the primary cancer there was an excess mortality for one year survivors, with deaths twice that of the background level (SMR= 2.2 (1.3-3.0)p=0.005 and although one and a half times background levels at 5 years, the excess mortality was not significant 1.5 (0.6-2.3 p=0.269). CONCLUSION: Whilst survival from childhood cancers is excellent, this work in common with larger studies, highlights the need for ongoing monitoring of cancer survivors. Preventable skin cancer was identified as a problem in young adults

Coherence vortices in one spatial dimension

Coherence vortices are screw-type topological defects in the phase of Glauber's two-point degree of quantum coherence, associated with pairs of spatial points at which an ensemble-averaged stochastic quantum field is uncorrelated. Coherence vortices may be present in systems whose dimensionality is too low to support spatial vortices. We exhibit lattices of such quantum-coherence phase defects for a one-dimensional model quantum system. We discuss the physical meaning of coherence vortices and propose how they may be realized experimentally.Comment: 5 pages, 3 figure

The Lessons of “Lesson Drawing”: How the Obama Administration Attempted to Learn from Failure of the Clinton Health Plan

The article examines the role of historical insights in the creation of U.S. healthcare policy. Particular focus is given to the influence of former U.S. President Bill Clinton\u27s 1993-1994 attempts at healthcare reform on the policies of U.S. President Barack Obama. It is suggested that while the U.S. Patient Protection and Affordable Care act of 2010 was successful in many respects, the Obama administration\u27s efforts to avoid missteps taken with Clinton\u27s Health Security Act did not significantly aid and sometimes even hindered its progress. Details on the political strategy, policy design, and political rhetoric used by both administrations are presented. Other topics include partisan politics and the communication of policy goals to the public

Gender differences in conceptual understanding of Newtonian mechanics: a UK cross-institution comparison

We present results of a combined study from three UK universities where we investigate the existence and persistence of a performance gender gap in conceptual understanding of Newtonian mechanics. Using the Force Concept Inventory, we find that students at all three universities exhibit a statistically significant gender gap, with males outperforming females. This gap is narrowed but not eliminated after instruction, using a variety of instructional approaches. Furthermore, we find that before instruction the quartile with the lowest performance on the diagnostic instrument comprises a disproportionately high fraction (~50%) of the total female cohort. The majority of these students remain in the lowest-performing quartile post-instruction. Analysis of responses to individual items shows that male students outperform female students on practically all items on the instrument. Comparing the performance of the same group of students on end-of-course examinations, we find no statistically significant gender gaps.Comment: 17 page

Attitudes Toward Dysfunctional Audit Behavior: The Effects Of Locus Of Control, Organizational Commitment, and Position

Dysfunctional audit behavior (DAB) is associated with decreased audit quality (Public Oversight Board 2000). While recent studies suggest that dysfunctional audit behavior is a widespread problem (Smith 1995; Otley and Pierce 1995), extant research fails to adequately explain the causes or determinants of this form of deviant behavior. This study develops and tests a theoretical model that identifies locus of control, position, and organizational commitment as antecedents of attitudes toward DAB. Using a cross-organizational design and a path analysis technique, survey results from 113 auditors support the theoretical model.