On Newton's method with a class of rational functions

AbstractThe classical Newton's method for determining a real factor of a polynomial is shown to be one member of a family of similar algorithms found by considering the roots of a class of rational functions. These algorithms are variants of the Birge Vieta method for solving polynomial equations. Methods for selecting an appropriate member of the family for a general problem are compared. Third order possibilities are shown to exist and results for a particular case are reported

A manifesto for a socio-technical approach to NHS and social care IT-enabled business change - to deliver effective high quality health and social care for all

80% of IT projects are known to fail. Adopting a socio-technical approach will help them to succeed in the future. The socio-technical proposition is simply that any work system comprises both a social system (including the staff, their working practices, job roles, culture and goals) and a technical system (the tools and technologies that support and enable work processes). These elements together form a single system comprising interacting parts. The technical and the social elements need to be jointly designed (or redesigned) so that they are congruent and support one another in delivering a better service. Focusing on one aspect alone is likely to be sub-optimal and wastes money (Clegg, 2008). Thus projects that just focus on the IT will almost always fail to deliver the full benefits

Joining emulsion droplets using colloidal rods

Many of the differences between conventional emulsions and particle-stabilized emulsions stem from the fact that the particles are mesoscopic objects. One curious difference is the phenomenon of bridging.[1] This is where colloidal particles are shared by more than one droplet. It results in emulsions with clusters of droplets that are all attached and it has the effect of making the emulsions very fragile.[2] Previous work in this area has focused on colloidal spheres. Here we explore the bridging behavior of droplets stabilized by colloidal rods. Our rods are spherocylinders which have an iron oxide core coated with a silica shell; in this work we use rods with aspect ratios 3 and 15. We find that bridging is ubiquitous for rod shaped particles, especially at high aspect ratio. Previously, computer simulations have shown that the adsorption of colloidal rods to liquid interfaces is likely to involve two steps which happen sequentially.[3] In the first step the rods are adsorbed to the interface; in the second step the rods reorient to lie with their long axis in the plane of the interface. Please click Additional Files below to see the full abstract

Managing risk in enterprise resource planning projects

Enterprise Resource Planning (ERP) projects are strategic and capital intensive, so failure may be costly and even cause bankruptcy of companies. Previous studies have proposed ways for improving implementation, but they are mostly generic and follow standardized project management practices as specified in various standards (e.g. the “project management body of knowledge” of the Project Management Institute). Because ERP is interdisciplinary (involving change management, project management and information technology management), it warrants a customized approach to managing risks throughout the life cycle of implementation and operation. Through a practical case study, this paper demonstrates a qualitative, user friendly approach to ERP project risk management. Firstly, through a literature review it identifies various risk factors in ERP implementation. Secondly, the risk management practices of a UK-based multinational consulting company in one of its clients are evaluated. The risk factors from the case study organization and literature are then compared and discussed

Transfer of Escherichia coli to water from drained and undrained grassland after grazing.

The aim of this study was to determine the load of Escherichia coli transferred via drainage waters from drained and undrained pasture following a grazing period. Higher concentrations (ranging between 104 and 103 CFU g-1) of E. coli persisted in soil for up to 60 days beyond the point where cattle were removed from the plots, but these eventually declined in the early months of spring to concentrations less than 102 CFU g-1. The decline reflects the combined effect of cell depletion from the soil store through both wash-out and die-off of E. coli. No difference (P 0.05) was observed in E. coli loads exported from drained and undrained plots. Similarly, no difference (P 0.05) was observed in E. coli concentrations in drainage waters of mole drain flow and overland plus subsurface interflow. Intermittent periods of elevated discharge associated with storm events mobilised E. coli at higher concentrations (e.g. in excess of 400 CFU ml-1) than observed during low flow conditions (often <25 CFU ml-1). The combination of high discharge and cell concentrations resulted in the export of E. coli loads from drained and undrained plots exceeding 106 CFU L-1 s-1. The results highlight the potential for drained land to export E. coli loads comparable to those transferred from undrained pasture

The Importance of Combinatorial Gene Expression in Early Mammalian Thalamic Patterning and Thalamocortical Axonal Guidance

The thalamus is essential for sensory perception. In mammals, work on the mouse has taught us most of what we know about how it develops and connects to the cortex. The mature thalamus of all mammalian species comprises numerous anatomically distinct collections of neurons called nuclei that differ in function, connectivity, and molecular constitution. At the time of its initial appearance as a distinct structure following neural tube closure, the thalamus is already patterned by the regional expression of numerous regulatory genes. This patterning, which lays down the blueprint for later development of thalamic nuclei, predates the development of thalamocortical projections. In this review we apply novel analytical methods to gene expression data available in the Allen Developing Mouse Brain Atlas to highlight the complex organized molecular heterogeneity already present among cells in the thalamus from the earliest stages at which it contains differentiating neurons. This early patterning is likely to invest in axons growing from different parts of the thalamus the ability to navigate in an ordered way to their appropriate area in the cerebral cortex. We review the mechanisms and cues that thalamic axons use, encounter, and interpret to attain the cortex. Mechanisms include guidance by previously generated guidepost cells, such as those in the subpallium that maintain thalamic axonal order and direction, and axons such as those of reciprocal projections from intermediate structures or from the cortex itself back toward the thalamus. We show how thalamocortical pathfinding involves numerous guidance cues operating at a series of steps along their route. We stress the importance of the combinatorial actions of multiple genes for the development of the numerous specific identities and functions of cells in this exquisitely complex system and their orderly innervation of the cortex

The clinical effectiveness and cost-effectiveness of ablative therapies in the management of liver metastases: systematic review and economic evaluation

Background: Many deaths from cancer are caused by metastatic burden. Prognosis and survival rates vary, but survival beyond 5 years of patients with untreated metastatic disease in the liver is rare. Treatment for liver metastases has largely been surgical resection, but this is feasible in only approximately 20–30% of people. Non-surgical alternatives to treat some liver metastases can include various forms of ablative therapies and other targeted treatments.Objectives: To evaluate the clinical effectiveness and cost-effectiveness of the different ablative and minimally invasive therapies for treating liver metastases.Data sources: Electronic databases including MEDLINE, EMBASE and The Cochrane Library were searched from 1990 to September 2011. Experts were consulted and bibliographies checked.Review methods: Systematic reviews of the literature were undertaken to appraise the clinical effectiveness and cost-effectiveness of ablative therapies and minimally invasive therapies used for people with liver metastases. Studies were any prospective study with sample size greater than 100 participants. A probabilistic model was developed for the economic evaluation of the technologies where data permitted.Results: The evidence assessing the clinical effectiveness and cost-effectiveness of ablative and other minimally invasive therapies was limited. Nine studies of ablative therapies were included in the review; each had methodological shortcomings and few had a comparator group. One randomised controlled trial (RCT) of microwave ablation versus surgical resection was identified and showed no improvement in outcomes compared with resection. In two prospective case series studies that investigated the use of laser ablation, mean survival ranged from 41 to 58 months. One cohort study compared radiofrequency ablation with surgical resection and five case series studies also investigated the use of radiofrequency ablation. Across these studies the median survival ranged from 44 to 52 months. Seven studies of minimally invasive therapies were included in the review. Two RCTs compared chemoembolisation with chemotherapy only. Overall survival was not compared between groups and methodological shortcomings mean that conclusions are difficult to make. Two case series studies of laser ablation following chemoembolisation were also included; however, these provide little evidence of the use of these technologies in combination. Three RCTs of radioembolisation were included. Significant improvements in tumour response and time to disease progression were demonstrated; however, benefits in terms of survival were equivocal. An exploratory survival model was developed using data from the review of clinical effectiveness. The model includes separate analyses of microwave ablation compared with surgery and radiofrequency ablation compared with surgery and one of radioembolisation in conjunction with hepatic artery chemotherapy compared with hepatic artery chemotherapy alone. Microwave ablation was associated with an incremental cost-effectiveness ratio (ICER) of £3664 per quality-adjusted life-year (QALY) gained, with microwave ablation being associated with reduced cost but also with poorer outcome than surgery. Radiofrequency ablation compared with surgical resection for solitary metastases &lt; 3 cm was associated with an ICER of –£266,767 per QALY gained, indicating that radiofrequency ablation dominates surgical resection. Radiofrequency ablation compared with surgical resection for solitary metastases ? 3 cm resulted in poorer outcomes at lower costs and a resultant ICER of £2538 per QALY gained. Radioembolisation plus hepatic artery chemotherapy compared with hepatic artery chemotherapy was associated with an ICER of £37,303 per QALY gained.Conclusions: There is currently limited high-quality research evidence upon which to base any firm decisions regarding ablative therapies for liver metastases. Further trials should compare ablative therapies with surgery, in particular. A RCT would provide the most appropriate design for undertaking any further evaluation and should include a full economic evaluation, but the group to be randomised needs careful selection.Source of funding: Funding for this study was provided by the Health Technology Assessment programme of the National Institute for Health Research