Bifurcation of Localized Disturbances in a Model Biochemical Reaction

Asymptotic solutions are presented to the nonlinear parabolic reaction-diffusion equations describing a model biochemical reaction proposed by I. Prigogine. There is a uniform steady state which, for certain values of the adjustable parameters, may be unstable. When the uniform solution is slightly unstable, the two-timing method is used to find the bifurcation of new solutions of small amplitude. These may be either nonuniform steady states or time-periodic solutions, depending on the ratio of the diffusion coefficients. When one of the parameters is allowed to depend on space and the basic state is unstable, it is found that the nonuniform steady state which is approached may show localized spatial oscillations. The localization arises out of the presence of turning points in the linearized stability equations

IMPACT OF NO-TILL TECHNOLOGIES IN GHANA

In the 1990s, no-till with mulch, a sustainable agricultural alternative, was introduced to Ghanaian farmers through a joint program between the Crops Research Institute in Kusami, Ghana, Sasakawa Global 2000, and the Monsanto Company. The package was disseminated to farmers in the Forest, Transition, and Guinea Savannah Zones, and rapidly adopted. In 2000, it was estimated that 100,000 small-scale farmers practiced no-till on 45,000 hectares of land. This study examines the impact of no-till on farmers who adopted the technology in the three zones, and to a lesser extent, the reasons for non-adoption. The impact of no-till among agrochemical dealers was also evaluated. The report found that no-till brought important changes to farmers using the technology and expanded the market for agrochemicals. It calls for more research on machinery for the technology, crop rotations, and the dynamics of diseases and weed and pest populations. More research on the organization and performance of agrochemical markets is also needed to identify bottlenecks that hamper the dissemination of no-till.Farm Management,

BOA: Framework for Automated Builds

Managing large-scale software products is a complex software engineering task. The automation of the software development, release and distribution process is most beneficial in the large collaborations, where the big number of developers, multiple platforms and distributed environment are typical factors. This paper describes Build and Output Analyzer framework and its components that have been developed in CMS to facilitate software maintenance and improve software quality. The system allows to generate, control and analyze various types of automated software builds and tests, such as regular rebuilds of the development code, software integration for releases and installation of the existing versions.Comment: 3 pages, 2 figure

Deputy Minister Salary in Canada: Economic and Political Forces

Since the late 1990s both the public and the federal and provincial governments in Canada have paid increasing attention to the issue of public sector salaries due to the availability of public compensation information, the aging of senior government officials and adoption of new public management by the public sector. This study investigates the factors determining the compensation level of senior government officials, namely deputy ministers (DMs), in the provincial and the federal governments in Canada. The key factors of interest are cabinet minister salaries, private sector salaries and the presence of pay-for-performance schemes. Using descriptive and regression analysis, this study shows that political elements play an important role in DM salary determination. In particular, regression results indicate a close relationship between DM and ministerial salaries during the period between 2000 and 2010. The relationship between DM salary and pay-for-performance schemes shows that DM salary is positively related to the presence of aggressive pay-for-performance schemes. This study argues that the introduction of pay-for-performance schemes is consistent with the politicization of the salary determination process for senior government officials. DMs with better performance are awarded with higher salaries in exchange for reaching performance measures that politicians lay out in advance

Control of invasive typha spp. in a restored freshwater wetland

Wetlands are critically important habitats that provide many ecosystem services but loss and degradation of wetland habitat and functions has led to the growing need to create and restore functionally sound wetlands. In temperate climates, Typha spp. are an invasive plant genus that is problematic for mitigation efforts as it spreads quickly and aggressively into disturbed habitats and creates monotypic stands with dense rhizomes that are difficult to eradicate. Control is most often attempted through mechanical cutting or application of herbicide. In this study I surveyed four mitigation wetland vegetation communities in two years to determine species distribution and change at HANA, locate areas invaded by four emergent wetland species (Typha spp., P. arundinacea, P. australis, L. salicaria), and monitor manual and chemical control efforts. P. arundinacea cover was reduced 81% by herbicide application and Typha spp. cover was reduced 38% overall, with greater reduction through mechanical cutting than herbicide. I conducted experimental manipulations following control and found that leaving floating Typha debris in deep water ponds after cutting did not negatively impact ecosystem recovery, and that the addition of organic carbon (sugar) limited Typha growth by 80% after herbicide, though I found no correlation between carbon addition and soil nitrogen to suggest nitrogen immobilization was the mechanism. Overall I found that there are many factors, including type of control, the post-control methods employed and the nutrient availability of the system, which significantly impact the recovery of aquatic and emergent wetland systems following control implementation. My investigations help to provide a better understanding of Typha invasion and potential improvements to control efforts

Long-range chromatin domains in yeast

The principal repeating subunit of chromatin is the nucleosome, which consists of a histone octamer complex, around which the DNA fibre coils. Adjacent nucleosomes are separated by short regions of linker DNA, within which a specialised Tinker' histone protein may bind to further compact the DNA. Chromatin organisation in Saccharomyces cerevisiae differs from that found in more complex organisms, primarily due to its relatively compact genome, which is made up of about 6000 genes. In yeast the average nucleosome repeat length is only 165bp compared to the 180-200bp linker length seen in higher eukaiyotes. Therefore, the majority of the yeast genome does not have sufficient linker length between nucleosomes to enable the binding of Tinker' histones and only areas with increased repeat length will be able to bind these specialised proteins.The FLOl gene locus includes a potentially gene-free 6kb upstream region that is mediated by SWI/SNF and Tupl-Ssn6. These complexes modulate nucleosome binding by altering the histone-DNA interactions and are pivotal to FLOl gene regulation (Fleming and Pennings, 2001). Interestingly, the nucleosome array in this region is most regularly spaced when the Tuplp co-repressor is present with an average nucleosome spacing of 180bp. Thus, it constitutes a region of chromatin in the yeast genome that could accommodate linker histones and / or the Tuplp repressor complex, leading to an area of higher-order chromatin compactionThe causal relationship between Hholp (yeast Tinker' histone) and Tuplp-Ssn6p binding was investigated in wildtype, ΔHHOl, ΔSNF2, ΔSSN6 and ΔTUP1 mutant 1 Abstract cells by chromatin immunoprecipitation in the FLOl upstream region. The 3D proximity of the two Tuplp peaks was investigated using chromatin conformation capture analyses, which showed that the Tuplp sites are closely aligned, except in ΔSNF2 strains. The change in the conformation of DNA may be influenced by changes in the acetylation of the core histones and / or a chromatin structure which alters the fluidity of the chromatin fibre

Electronic swallowing intervention package to support swallowing function in patients with head and neck cancer: development and feasibility study

Background: Many patients undergoing treatment for head and neck cancer (HNC) experience significant swallowing difficulties, and there is some evidence that swallowing exercises may improve outcomes, including quality of life. This feasibility study developed an evidence-based, practical Swallowing Intervention Package (SiP) for patients undergoing chemo-radiotherapy (CRT) for HNC. As part of the study, an electronic version of SiP (e-SiP) was concurrently developed to support patients to self-manage during treatment. This paper reports on the e-SiP component of this work. Objective: To develop and conduct preliminary evaluation of an electronic support system (e-SiP) for patients undergoing CRT for head and neck cancer. Methods: The study involved health professionals and patients who were undergoing CRT for head and neck cancer. The scoping stage of e-SiP development involved investigated the potential usefulness of e-SiP, exploring how e-SiP would look and feel and what content would be appropriate to provide. Patient and carer focus groups and a health professionals’ consensus day were used as a means of data gathering around potential e-SiP content. A repeat focus group looked at an outline version of e-SIP and informed the next stage of its development around requirements for tool. This was followed by further development and a testing stage of e-SiP involved the coding of a prototype which was then evaluated using a series of steering group meetings, semi-structured interviews with both patients and health care professionals, and analysis of e-SiP log data. Results: Feedback from focus groups and health professional interviews was very positive and it was felt e-SiP use would support and encourage patients in conducting their swallowing exercises. However, of the ten patients offered e-SIP, only two opted to use it. For these patients, aspects of the e-SIP application were considered useful, in particular the ease of keeping a diary of exercises performed. Interviews with users and non-users suggested significant barriers to its use. Most significantly the lack of flexibility of platform on which e-SiP could be accessed appeared a dominant factor in deterring e-SiP use. Conclusions: Results suggest a need for further research to be conducted around the implementation of e-SiP. This involves evaluating how e-SiP can be better integrated into usual care, and through patient training and staff engagement, can be seen as a beneficial tool to help support patients in conducting swallowing exercises