Results of monitoring at the British library excavation

The main phase of excavation for the basements of the British Library at St Pancras, London, was completed in 1987. The project included basements extending up to 25 m deep, through the London Clay and into the Lambeth Group. The excavations were formed using both the top-down method and open excavation with ground anchors. Existing major buildings lie within 25 m of the site and London Underground tunnels lie below and adjacent to the site. The purpose of this paper is to present the results of displacement monitoring; they are summarised in the paper and presented in more detail in online supplementary data files. The retaining walls advanced towards the site by up to about 32 mm and the clays expanded rapidly on unloading beneath the excavations, causing the Victoria Line tunnels to heave by up to 22 mm. The slow progress of the project provided an unusual opportunity to monitor ground and structure movements in the surroundings before site activity began. Ironically, it was found that the largest settlements of adjacent buildings were caused by the installation of equipment intended to measure the settlements. Extensive condition surveys were carried out, but no damage to adjacent structures or tunnels has been recorded. </jats:p

Discovering an active subspace in a single-diode solar cell model

Predictions from science and engineering models depend on the values of the model's input parameters. As the number of parameters increases, algorithmic parameter studies like optimization or uncertainty quantification require many more model evaluations. One way to combat this curse of dimensionality is to seek an alternative parameterization with fewer variables that produces comparable predictions. The active subspace is a low-dimensional linear subspace defined by important directions in the model's input space; input perturbations along these directions change the model's prediction more, on average, than perturbations orthogonal to the important directions. We describe a method for checking if a model admits an exploitable active subspace, and we apply this method to a single-diode solar cell model with five input parameters. We find that the maximum power of the solar cell has a dominant one-dimensional active subspace, which enables us to perform thorough parameter studies in one dimension instead of five

The changing effects of social protection on poverty

This paper fits within a broader research programme concerned with the processes that link labour market precarity and social exclusion. Labour market insecurity manifests itself most directly in the form of unemployment, and other elements in the programme seek to measure the impact of precarity, and unemployment in particular, on poverty and social exclusion in the eight countries covered. One of the principal concerns of the programme is however the extent to which institutional differences across countries with respect to the labour market and social protection are a significant factor mediating the relationship between labour market precarity and social exclusion. This paper focuses on the effectiveness of cash transfers, the central element of social protection systems, in alleviating the effects of unemployment on income poverty. The structures of social protection systems vary greatly across European Union member states, and in many cases have altered significantly in recent years in response to high unemployment (see Hauser et al, 1998). Using data from the mid-1980s and the mid-1990s for six member countries, the paper compares the effectiveness of different systems in lifting or keeping the unemployed out of poverty, and how this has been affected by the way systems have responded to the challenges produced by developments in the labour market in the past decade. The specific role of social insurance-based unemployment-linked transfers versus other cash transfers is also considered, to assess the extent to which social insurance has been able to cope with changes in the labour market over the period. The data come from a variety of national large-scale household surveys. The paper is structured as follows. Section 2 discusses the data and methods to be employed in measuring the impact of cash transfers on poverty risks for the unemployed. Section 3 looks at the overall risks of poverty for the unemployed before and after cash transfers, and how these changed between the mid-1980s and mid-1990s. Section 4 looks at the role of social insurance-based unemployment payments versus other cash transfers. Section 5 examines the extent to which the impact of transfers varies by gender and by duration of unemployment. Section 6 highlights the key patterns identified and what these tell us about the relationship between the type of welfare regime a country operates and effectiveness in alleviating poverty among the unemployed

Economic associations among causes of species endangerment in the United States.

Associations among causes of species endangerment in the United States reflect the integration of economic sectors, supporting the theory and evidence that economic growth proceeds at the competitive exclusion of nonhuman species in the aggregate.economic growth; biodiversity; endangered species

Mixtures of Shifted Asymmetric Laplace Distributions

A mixture of shifted asymmetric Laplace distributions is introduced and used for clustering and classification. A variant of the EM algorithm is developed for parameter estimation by exploiting the relationship with the general inverse Gaussian distribution. This approach is mathematically elegant and relatively computationally straightforward. Our novel mixture modelling approach is demonstrated on both simulated and real data to illustrate clustering and classification applications. In these analyses, our mixture of shifted asymmetric Laplace distributions performs favourably when compared to the popular Gaussian approach. This work, which marks an important step in the non-Gaussian model-based clustering and classification direction, concludes with discussion as well as suggestions for future work

Binary Black Hole Accretion During Inspiral and Merger

We present the results of 2D, moving mesh, viscous hydrodynamical simulations of accretion onto merging supermassive black hole (SMBH) binaries. We include viscous heating, shock heating, and radiative cooling, and simulate the transition from the "pre-decoupling" epoch, where the inspiral timescale is longer than the viscous timescale, to the "post-decoupling" epoch, where the inspiral timescale is shorter than the viscous timescale. We find that there is no abrupt halt to the accretion at decoupling, but rather the accretion shows a slow decay, with significant accretion well after the expected decoupling. Moreover, we find that the luminosity in X-rays is significantly higher prior to the merger, as orbital energy from the SMBH binary is converted to heat via strong shocks inside the cavity, and radiated away. Following the merger, the cavity refills viscously and the accretion rate relaxes to the Shakura-Sunyaev value, while the X-ray luminosity drops as the shocks quickly dissipate