From buildings to cities: techniques for the multi-scale analysis of urban form and function

The built environment is a significant factor in many urban processes, yet direct measures of built form are seldom used in geographical studies. Representation and analysis of urban form and function could provide new insights and improve the evidence base for research. So far progress has been slow due to limited data availability, computational demands, and a lack of methods to integrate built environment data with aggregate geographical analysis. Spatial data and computational improvements are overcoming some of these problems, but there remains a need for techniques to process and aggregate urban form data. Here we develop a Built Environment Model of urban function and dwelling type classifications for Greater London, based on detailed topographic and address-based data (sourced from Ordnance Survey MasterMap). The multi-scale approach allows the Built Environment Model to be viewed at fine-scales for local planning contexts, and at city-wide scales for aggregate geographical analysis, allowing an improved understanding of urban processes. This flexibility is illustrated in the two examples, that of urban function and residential type analysis, where both local-scale urban clustering and city-wide trends in density and agglomeration are shown. While we demonstrate the multi-scale Built Environment Model to be a viable approach, a number of accuracy issues are identified, including the limitations of 2D data, inaccuracies in commercial function data and problems with temporal attribution. These limitations currently restrict the more advanced applications of the Built Environment Model

Arrays of Josephson junctions between unconventional superconductors

We study large arrays of mesoscopic junctions between gapless superconductors where the tunneling processes of both, particle-hole and Cooper, pairs give rise to a strongly retarded effective action which, contrary to the standard case, can not be readily characterized in terms of a local Josephson energy. This complexity is expected to arise in, e.g., the grain boundary and c-axis junctions in layered high-T_c superconductors. A new representation for describing collective phenomena in this system is introduced, and its phase diagram is discussed, alongside the electrical conductivity.Comment: Latex, 4+ pages, 1 figur

A good start equals a good stay: providing a positive induction experience

Universities are only too aware of the ways in which their student profiles are changing, however it remains a challenge for staff to identify how they should respond to the increasing diversity resulting from widening participation. This paper aims to identify areas of the induction process that meets the needs of first year students in a pre and post 1992 higher education institutions, namely Brunel and Middlesex. These two London based universities have good performance indicators for widening participation holding positions one and two in the list of institutions that have expanded full time undergraduate numbers in HEFCE (2001), and have both developed Access Agreements to recruit the brightest and most disadvantaged students in 2006. The universities are geographical competitors; therefore strategies to attract and retain students are central to their existence. However, the universities represent different ends of the retention spectrum; one has a withdrawal rate of less than 7% while the other has a rate of 15%. Nevertheless, both universities recognise that the initial induction process has a significant impact upon a student's perceptions of the university and plays a vital role in a student's decision to either continue with their studies or withdraw as stated in their missions and visions. The current study reports on the collaborative findings of research during the first six weeks of the autumn term 2003. This paper reports on the joint findings of the students’ reflections on their induction experience with the particular emphasis on the students’ perception of the purpose of induction, their satisfaction with the this period and gives suggestions on developing effective induction strategies. The results reveal that although the institutions are vastly different, they face similar problem issues. The task of universities old and new is to recognise value and respond to these needs

Time step rescaling recovers continuous-time dynamical properties for discrete-time Langevin integration of nonequilibrium systems

When simulating molecular systems using deterministic equations of motion (e.g., Newtonian dynamics), such equations are generally numerically integrated according to a well-developed set of algorithms that share commonly agreed-upon desirable properties. However, for stochastic equations of motion (e.g., Langevin dynamics), there is still broad disagreement over which integration algorithms are most appropriate. While multiple desiderata have been proposed throughout the literature, consensus on which criteria are important is absent, and no published integration scheme satisfies all desiderata simultaneously. Additional nontrivial complications stem from simulating systems driven out of equilibrium using existing stochastic integration schemes in conjunction with recently-developed nonequilibrium fluctuation theorems. Here, we examine a family of discrete time integration schemes for Langevin dynamics, assessing how each member satisfies a variety of desiderata that have been enumerated in prior efforts to construct suitable Langevin integrators. We show that the incorporation of a novel time step rescaling in the deterministic updates of position and velocity can correct a number of dynamical defects in these integrators. Finally, we identify a particular splitting that has essentially universally appropriate properties for the simulation of Langevin dynamics for molecular systems in equilibrium, nonequilibrium, and path sampling contexts.Comment: 15 pages, 2 figures, and 2 table

Cluster optimisation using Cgroups at a tier-2

The Linux kernel feature Control Groups (cgroups) has been used to gather metrics on the resource usage of single and eight-core ATLAS workloads. It has been used to study the effects on performance of a reduction in the amount of physical memory. The results were used to optimise cluster performance, and consequently increase cluster throughput by up to 10%

Wrong without a Remedy - North Carolina and the Wrongful Death of a Stillborn

This comment ... presents a legal argument supporting a civil action for the wrongful death of some stillborns and suggests that a gestational age of twenty-six weeks represents an appropriate viability standard in interpreting the North Carolina wrongful death statute. It also attempts to bridge the perceptual gap between certain aspects of medical and social sciences and the law regarding the fetus. The argument in support of the twenty-six week viability standard is presented in four parts. First, this comment illustrates why the fetus now enjoys an elevated status in society. Second, it illustrates the devastating impact of a stillbirth on the survivors. Third, it examines the born alive requirement and demonstrates that this requirement does not represent a well-defined line of demarcation, nor is it in the best interest of the public. Finally, it recommends that North Carolina courts interpret the wrongful death statute to include fetuses who have reached a gestational age of twenty-six weeks, because this age is: an age consistent with a medical viability standard; an age at which abortion ceases to be a maternal, medical, or legal option; an age at which maternal attachment is well-developed; and an age during which the fetus exhibits true attributes of personhood

Random planar graphs and the London street network

In this paper we analyse the street network of London both in its primary and dual representation. To understand its properties, we consider three idealised models based on a grid, a static random planar graph and a growing random planar graph. Comparing the models and the street network, we find that the streets of London form a self-organising system whose growth is characterised by a strict interaction between the metrical and informational space. In particular, a principle of least effort appears to create a balance between the physical and the mental effort required to navigate the city

Wrong without a Remedy - North Carolina and the Wrongful Death of a Stillborn

This comment ... presents a legal argument supporting a civil action for the wrongful death of some stillborns and suggests that a gestational age of twenty-six weeks represents an appropriate viability standard in interpreting the North Carolina wrongful death statute. It also attempts to bridge the perceptual gap between certain aspects of medical and social sciences and the law regarding the fetus. The argument in support of the twenty-six week viability standard is presented in four parts. First, this comment illustrates why the fetus now enjoys an elevated status in society. Second, it illustrates the devastating impact of a stillbirth on the survivors. Third, it examines the born alive requirement and demonstrates that this requirement does not represent a well-defined line of demarcation, nor is it in the best interest of the public. Finally, it recommends that North Carolina courts interpret the wrongful death statute to include fetuses who have reached a gestational age of twenty-six weeks, because this age is: an age consistent with a medical viability standard; an age at which abortion ceases to be a maternal, medical, or legal option; an age at which maternal attachment is well-developed; and an age during which the fetus exhibits true attributes of personhood