Geospatial aspects of catchment hydrology

The catchment is a fundamental unit of study in hydrology. It is normally well defined topographically, can be studied as a series of nested units (larger catchments are made of many smaller sub-catchments), and is an open system for measuring inputs and outputs of mass and energy. Catchments are usually delineated by land-surface topography and are made of hillslopes and channels. The proportion of hillslope area to channel density or total channel length may determine how efficiently water can be removed from a catchment since water in channels tends to move much more quickly than water across and through hillslopes. Thus the spatial layout of hillslopes and channels is important. This article describes some basic principles of catchment hydrology and illustrates how determining spatial factors involved is fundamental for understanding how environmental change may impact on runoff production and resulting river flow

Restoration of seventeenth century water gardens at Bramham Park

Bramham Park, near Wetherby, is the only large-scale formal garden in the UK to survive virtually unchanged from the late seventeenth and early eighteenth centuries. During the Victorian period most such gardens were altered as styles and trends changed through time

An adjoint for likelihood maximization

The process of likelihood maximization can be found in many different areas of computational modelling. However, the construction of such models via likelihood maximization requires the solution of a difficult multi-modal optimization problem involving an expensive O(n3) factorization. The optimization techniques used to solve this problem may require many such factorizations and can result in a significant bottle-neck. This article derives an adjoint formulation of the likelihood employed in the construction of a kriging model via reverse algorithmic differentiation. This adjoint is found to calculate the likelihood and all of its derivatives more efficiently than the standard analytical method and can therefore be utilised within a simple local search or within a hybrid global optimization to accelerate convergence and therefore reduce the cost of the likelihood optimization

Do Different Groups Invest Differently in Higher Education?

On average, education accounts for about 2 percent of total annual expenditures by U.S. consumers, but this percentage varies greatly by demographic. Some groups appear to spend much more than others, so it is natural to question what influences this variation in spending. A popular conception is that racial and ethnic groups value higher education differently. In economic terms, this is a reflection of the value of human capital—how much people are willing to invest in their children’s education. The notion that some groups invest more than others is often based on average participation rates but does not account for actual expenditures or the expenditures when you consider socioeconomic differences. This Beyond the Numbers article looks at the amount of money invested in education by different race and ethnic groups and examines different factors that could contribute to the differences in expenditures. We find that race and ethnicity groups do, on average, spend vastly different amounts on education, but the likelihood of going to college (and thus having education expenditures) and socioeconomic factors have the most influence on families’ investment in higher education—and race and ethnicity is not the driving factor, as commonly thought

Balanced-bellows spirometer

Compact balanced-bellows dry type spirometer was designed to be insensitive to acceleration fields along any or all coordinate axes. It provides true indication of respiratory action of test subject without need for calibration in acceleration fields

Activity Theory Analysis of Heart Failure Self-Care

The management of chronic health conditions such as heart failure is a complex process emerging from the activity of a network of individuals and artifacts. This article presents an Activity Theory-based secondary analysis of data from a geriatric heart failure management study. Twenty-one patients' interviews and clinic visit observations were analyzed to uncover eight configurations of roles and activities involving patients, clinicians, and others in the sociotechnical network. For each configuration or activity pattern, we identify points of tension and propose guidelines for developing interventions for future computer-supported healthcare systems

The algebro-geometric initial value problem for the Ablowitz-Ladik hierarchy

We discuss the algebro-geometric initial value problem for the Ablowitz-Ladik hierarchy with complex-valued initial data and prove unique solvability globally in time for a set of initial (Dirichlet divisor) data of full measure. To this effect we develop a new algorithm for constructing stationary complex-valued algebro-geometric solutions of the Ablowitz-Ladik hierarchy, which is of independent interest as it solves the inverse algebro-geometric spectral problem for general (non-unitary) Ablowitz-Ladik Lax operators, starting from a suitably chosen set of initial divisors of full measure. Combined with an appropriate first-order system of differential equations with respect to time (a substitute for the well-known Dubrovin-type equations), this yields the construction of global algebro-geometric solutions of the time-dependent Ablowitz-Ladik hierarchy. The treatment of general (non-unitary) Lax operators associated with general coefficients for the Ablowitz-Ladik hierarchy poses a variety of difficulties that, to the best of our knowledge, are successfully overcome here for the first time. Our approach is not confined to the Ablowitz-Ladik hierarchy but applies generally to (1+1)-dimensional completely integrable soliton equations of differential-difference type.Comment: 47 page

Coming of age

Copyright at Demos 2011. This work is made available under the terms of the Demos licence.Britain’s ageing population is often described as a demographic time-bomb. As a society we often view ageing as a ‘problem’ which must be ‘managed’ – how to cope with the pressure on national health services of growing numbers of older people, the cost of sustaining them with pensions and social care, and the effect on families and housing needs. But ageing is not a policy problem to be solved. Instead it is a normal part of life, which varies according to personal characteristics, experience and outlook, and for many people growing older can be a very positive experience. Drawing on the Mass Observation project, one of the longest-running longitudinal life-writing projects anywhere in the world, Coming of Age grounds public policy in people’s real, lived experiences of ageing. It finds that the experience of ageing is changing, so that most people who are now reaching retirement do not identify themselves as old. One-size-fits-all policy approaches that treat older people as if they are all alike are alienating and inappropriate. Instead, older people need inclusive policy approaches that enable them to live their lives on their own terms. To ensure that older people are actively engaged, policy makers should stop emphasising the costs posed by an ageing population and start building on the many positive contributions that older people already make to our society.The Research Support and Development Office (RSDO) at Brunel University and the Economic and Social Research Council (ESRC

Slicing of silicon into sheet material. Silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

Fabrication of a prototype large capacity multiple blade slurry saw is considered. Design of the bladehead which will tension up to 1000 blades, and cut a 45 cm long silicon ingot as large as 12 cm in diameter is given. The large blade tensioning force of 270,000 kg is applied through two bolts acting on a pair of scissor toggles, significantly reducing operator set-up time. Tests with an upside-down cutting technique resulted in 100% wafering yields and the highest wafer accuracy yet experienced with MS slicing. Variations in oil and abrasives resulted only in degraded slicing results. A technique of continuous abrasive slurry separation to remove silicon debris is described

A network-indexbased version of TOPMODEL for use with high-resolution digital topographic data

This paper describes the preliminary development of a network index approach to modify and to extend the classic TOPMODEL. Application of the basic Beven and Kirkby (1979) form of TOPMODEL to high resolution (2.0 m) laser altimetric data (based upon the U.K. Environment Agency’s Light Detection and Ranging (LIDAR) system) to a 13.8 km(2) catchment in an upland environment identified large areas of saturated areas that remained unconnected from the drainage network even during an extreme flood event. This is shown to be a particular problem with using high resolution topographic data especially over large spatial scales. To deal with the hydrological consequences of disconnected areas, we present a simple network index modification in which saturated areas only connect when the topographic index is sufficient for there to be zero or negative saturation deficits along a complete flow path. This is combined with an enhanced method for dealing with the problem of pits and hollows which is shown to become more acute with higher resolution topographic data. The paper concludes by noting the implications of the research as presented for both methodological and substantive research that is currently under way