NGC1052 - A study of the pc-scale twin jet

We present results of a VLBA multi-frequency study of the pc-scale twin jet in NGC1052. We observed this object at epoch 1998.99 with the VLBA at 5, 8.4, 22 and 43 GHz both in total and linearly polarized intensity. The spectral analysis confirms the necessity of a free-free absorbing medium, obscuring the innermost part of both jets. At 5 GHz we found a compact linearly polarized emission region at the base of the eastern jet with a degree of polarization of 1.5%. At higher frequencies there is no evidence for polarization in our data. A core shift analysis constrains the position of the central engine to ~0.03 pc. The shift rates of the apparent core position with frequency confirm the strong influence of free-free absorption in conjunction with steep pressure gradients at the bases of both jets.Comment: Proceedings of the conference "SRT: the impact of large antennas on Radio Astronomy and Space Science", Cagliari, Italy, 7-10 November 2001, in press; 6 pages, 5 figures, needs srt_style.st

Risk Perceptions of Arsenic in Tap Water and Consumption of Bottled Water

The demand for bottled water has increased rapidly over the past decade, but bottled water is extremely costly compared to tap water. The convenience of bottled water surely matters to consumers, but are others factors at work? This manuscript examines whether purchases of bottled water are associated with the perceived risk of tap water. All of the past studies on bottled water consumption have used simple scale measures of perceived risk that do not correspond to risk measures used by risk analysts. We elicit a probability-based measure of risk and find that as perceived risks rise, expenditures for bottled water rise.Environmental Economics and Policy, Risk and Uncertainty, Q25, Q53, I12,

Evaluation of Causes of Construction Material Waste: Case of River State, Nigeria

This research paper evaluates the causes of construction waste generation on building sites in Rivers State, Nigeria. The methods employed to collect data include review of relevant literature and structured questionnaire. The statistical techniques used to analyse the data collected are Mean score method, ranking method and Man-Whitney U test. The results of analysis showed that the three most important factors contributing to construction material waste generation on building sites in Rivers State, Nigeria are ‘’rework contrary to drawing and specification”, “design changes and revision” and “waste from uneconomical shapes” respectively. It was also discovered that inappropriate equipment contributed least to waste generation on site and there is little “bottle neck” in obtaining work permit by contractors in Rivers State, Nigeria. The study revealed that all the 74 factors were considered important by the respondents. The study showed that there is no significant difference between the consultants and contractors perception about the factors affecting construction waste generation on building sites in Rivers State, Nigeria. This study therefore recommended that construction stakeholders should consider the studied factors at every level of the construction processes and in their waste management plan.Key words: Building Sites, Construction Waste, Evaluation, Factors, Nigeri

Comparing leadership internationally: challenges and reflections

This paper is a co-written paper by five MA Education students at the University of Northampton and James Underwood, Principal Lecturer at the University of Northampton and a PhD student at the University of Cambridge. We are all currently engaged in research that involves comparing aspects of education in the UK with another nation. The research that we are each personally undertaking addresses a range of topics. These all relate to an aspect of education leadership ranging from student leadership to school and university management. There is one common underlying research question which underpins all the studies which is: in what ways has comparison between nations been a valid approach to understanding education and leadership? This question is addressed successively via our individual stories in this paper. This paper is linked to a paper presented in May 2015 at the University of Cambridge entitled: “Breaking boundaries as writers, researchers and me-searchers, the challenges and rewards of completing an MA as a community of practice.” In which we discussed in depth our experience as a research community. This paper has therefore also been informed by a distinct perspective on the nature of Masters’ level study

Henri Temianka correspondence, Gurs

https://digitalcommons.chapman.edu/tobin_gurs_et_al_correspondence/1011/thumbnail.jp

Quadratic Word Equations with Length Constraints, Counter Systems, and Presburger Arithmetic with Divisibility

Word equations are a crucial element in the theoretical foundation of constraint solving over strings, which have received a lot of attention in recent years. A word equation relates two words over string variables and constants. Its solution amounts to a function mapping variables to constant strings that equate the left and right hand sides of the equation. While the problem of solving word equations is decidable, the decidability of the problem of solving a word equation with a length constraint (i.e., a constraint relating the lengths of words in the word equation) has remained a long-standing open problem. In this paper, we focus on the subclass of quadratic word equations, i.e., in which each variable occurs at most twice. We first show that the length abstractions of solutions to quadratic word equations are in general not Presburger-definable. We then describe a class of counter systems with Presburger transition relations which capture the length abstraction of a quadratic word equation with regular constraints. We provide an encoding of the effect of a simple loop of the counter systems in the theory of existential Presburger Arithmetic with divisibility (PAD). Since PAD is decidable, we get a decision procedure for quadratic words equations with length constraints for which the associated counter system is \emph{flat} (i.e., all nodes belong to at most one cycle). We show a decidability result (in fact, also an NP algorithm with a PAD oracle) for a recently proposed NP-complete fragment of word equations called regular-oriented word equations, together with length constraints. Decidability holds when the constraints are additionally extended with regular constraints with a 1-weak control structure.Comment: 18 page

Long-term outcome after lambrinudi operation in severe rigid equinus deformity

Concurrent Free Papers 7 - Paediatric Orthopaedics / General Orthopaedics: no. 7.3INTRODUCTION: Patients with severe rigid equinus deformity require corrective osteotomies to achieve a plantigrade foot. One such operation is the Lambrinudi triple arthrodesis. Many of these patients suffer from post-poliomyelitis deformity and have this operation within the first 2 decades of life. However, there is little in the literature describing long-term outcomes of these patients beyond 20 years. The study looked at the outcomes of patients from our centre over 30 years after their operations. METHODS: We traced 16 patients who had Lambrinudi operations at the Duchess of Kent Children’s Hospital from 1974 to 1979. The latest outcomes of 10 of these patients were found in the Clinical ...published_or_final_versio