The Local Compressibility of Liquids near Non-Adsorbing Substrates: A Useful Measure of Solvophobicity and Hydrophobicity?

We investigate the suitability of the local compressibility chi(z) as a measure of the solvophobicity or hydrophobicity of a substrate. Defining the local compressibility as the derivative of the local one-body density w.r.t. the chemical potential at fixed temperature, we use density functional theory (DFT) to calculate chi(z) for a model fluid, close to bulk liquid-gas coexistence, at various planar substrates. These range from a `neutral' substrate with a contact angle of approximately 90 degrees, which favours neither the liquid nor the gas phase, to a very solvophobic, purely repulsive substrate which exhibits complete drying (i.e. contact angle 180 degrees). We find that the maximum in the local compressibility, which occurs within one-two molecular diameters of the substrate, and the integrated quantity chi_ex (the surface excess compressibility, defined below) both increase rapidly as the contact angle increases and the substrate becomes more solvophobic. The local compressibility provides a more pronounced indicator of solvophobicity than the density depletion in the vicinity of the surface which increases only weakly with increasing contact angle. When the fluid is confined in a parallel slit with two identical solvophobic walls, or with competing solvophobic and solvophilic walls, chi(z) close to the solvophobic wall is altered little from that at the single substrate. We connect our results with simulation studies of water near to hydrophobic surfaces exploring the relationship between chi(z) and fluctuations in the local density and between chi_ex and the mean-square fluctuation in the number of adsorbed molecules.Comment: 23 pages, 9 figures, submitted to Journal of Physics: Condensed Matter as a Special Issue Articl

A hopeful therapy for Niemann-Pick C diseases

Not abstract availabl

Evolution of Risk and Political Regimes

The article contributes to the growing literature on intermediate regiimes by presenting a model that incorporates key features of such regimes and generates several of the "stylized facts" that characterize their behavior: their political volatility, cross nationality and over time, and the veriability of their economic performance something that renders their economies among the fastest growing and declining in global samples. Using an instrumental veriables approach, we test the model employing cross-national data.

The ephemeral aesthetic of spontaneous design on the streets of São Paulo, Brazil

There are few opportunities when the poor and prosperous can be spoken about with respect to the same, shared cultural experience. And yet, visual culture, and the design process that contributes to its materialisation in specific contexts, offers an opportunity to recognise a socially inclusive activity that reveals similarity rather than difference. This paper celebrates an ephemeral aesthetic that is appreciated by people at different ends of the economic, political and social spectrum. A mutual appreciation for the medium of collage differs only in terms of the environment within which the recycled object is eventually revealed. This paper explores some of these different contexts, and those who recognise and practise this phenomenon in a South American and European context. The conclusion of this speculative and exploratory study is that there is potential to develop this unique medium as an accessible and inclusive visual language, giving voice to those who often do not have the opportunity or the means to speak and be heard. Collage is recognised as a channel that mediates between social exclusion and inclusion when political and economic means have been exhausted. The resulting ephemeral aesthetic is proven to have visual appeal, satisfying low- and high-order human needs. Keywords: Bricolage; Ephemeral Aesthetic; Urban Poor; Human Need; Graphic Design</p

Problems and Prospects of Interdisciplinarity: The Case of Philosophy of Science

In this paper, we discuss some problems and prospects of interdisciplinary encounters by focusing on philosophy of science as a case study. After introducing the case, we give an overview about the various ways in which philosophy of science can be interdisciplinary in Section 2. In Section 3, we name some general problems concerning the possible points of interaction between philosophy of science and the sciences studied. In Section 4 we compare the advantages and risks of interdisciplinarity for individual researchers and institutions. In Section 5, we discuss interdisciplinary PhD programs, in particular concerning two main problems: increased workload and the quality of supervision. In the final Section 6, we look at interdisciplinary careers beyond the PhD

Training Echo State Networks with Regularization through Dimensionality Reduction

In this paper we introduce a new framework to train an Echo State Network to predict real valued time-series. The method consists in projecting the output of the internal layer of the network on a space with lower dimensionality, before training the output layer to learn the target task. Notably, we enforce a regularization constraint that leads to better generalization capabilities. We evaluate the performances of our approach on several benchmark tests, using different techniques to train the readout of the network, achieving superior predictive performance when using the proposed framework. Finally, we provide an insight on the effectiveness of the implemented mechanics through a visualization of the trajectory in the phase space and relying on the methodologies of nonlinear time-series analysis. By applying our method on well known chaotic systems, we provide evidence that the lower dimensional embedding retains the dynamical properties of the underlying system better than the full-dimensional internal states of the network

Factor Prices and Factor Substitution in U.S. Firms' Manufacturing Affiliates Abroad

Using confidential individual firm data from the Bureau of Economic Analysis survey of U.S. firms' manufacturing operations abroad, we investigate the determinants of capital intensity in affiliate operations. Host country labor cost, the scale of host country production, and the capital intensity of the parent firm's production in the United States, are all significant influences. The parent's capital intensity is the strongest and most consistent determinant of affiliate capital intensity. Affiliates that export are more sensitive to these factors in their choice of factor proportions than affiliates that sell only in their host countries.