Pseudopolymorphism in Brucine: Brucine-Water (1/2), The Third Crystal Hydrate of Brucine

The structure of the third pseudopolymorphic hydrate of brucine, brucine-water (1/2) [systematic name 2,3-dimethoxystrychnidin-10-one-water (1/2)], C23H26N2O4 . 2H2O, has been determined at 130 K. The asymmetric unit comprises two independent brucine molecules and four water molecules of solvation. The four water molecules form uncommon cyclic hydrogen-bonded homomolecular R2/2(8) tetramer rings, which then form primary hydrogen-bonded chain substructures, extending down the 21 screw axis in the unit cell. The two brucine molecules are linked peripherally to these substructures by either single O-H...O(brucine) or O-H...N(brucine) hydrogen bonds

Rich Nations, Poor Nations: How much can multiple equilibria explain?

The idea that income differences between rich and poor nations arise through multiple equilibria or 'poverty traps' is as intuitive as it is difficult to verify. In this paper, we explore the empirical relevance of such models. We calibrate a simple two sector model for 127 countries, and use the results to analyze the international prevalence of poverty traps and their consequences for productivity. We also examine the possible effects of multiplicity on the world distribution of income, and identify events in the data that may correspond to equilibrium switching.

The small-scale solar surface dynamo

The existence of a turbulent small-scale solar surface dynamo is likely, considering existing numerical and laboratory experiments, as well as comparisons of a small-scale dynamo in MURaM simulations with Hinode observations. We find the observed peaked probability distribution function (PDF) from Stokes-V magnetograms is consistent with a monotonic PDF of the actual vertical field strength. The cancellation function of the vertical flux density from a Hinode SP observation is found to follow a self-similar power law over two decades in length scales down to the ~200 km resolution limit. This provides observational evidence that the scales of magnetic structuring in the photosphere extend at least down to 20 km. From the power law, we determine a lower bound for the true quiet-Sun mean vertical unsigned flux density of ~43 G, consistent with our numerically-based estimates that 80% or more of the vertical unsigned flux should be invisible to Stokes-V observations at a resolution of 200 km owing to cancellation. Our estimates significantly reduce the order-of-magnitude discrepancy between Zeeman- and Hanle-based estimates.Comment: Proceedings of the Second Hinode Science Meeting, ASP Series 2009. 8 pages, 4 figure

The systemic response to topical Aldara treatment is mediated through direct TLR7 stimulation as Imiquimod enters the circulation

Topical application of Aldara cream, containing the Toll-like receptor 7/8 agonist Imiquimod, is a widely used mouse model for investigating the pathogenesis of psoriasis. We have previously used this model to study the effects of peripheral inflammation on the brain, and reported a brain-specific response characterised by increased transcription, infiltration of immune cells and anhedonic-like behavior. Here, we perform a more robust characterisation of the systemic response to Aldara application and find a potent but transient response in the periphery, followed by a prolonged response in the brain. Mass spectrometry analysis of plasma and brain samples identified significant levels of Imiquimod in both compartments at molar concentrations likely to evoke a biological response. Indeed, the association of Imiquimod with the brain correlated with increased Iba1 and GFAP staining, indicative of microglia and astrocyte reactivity. These results highlight the potency of this model and raise the question of how useful it is for interpreting the systemic response in psoriasis-like skin inflammation. In addition, the potential impact on the brain should be considered with regards to human use and may explain why fatigue, headaches and nervousness have been reported as side effects following prolonged Aldara use

Rich nations, poor nations: how much can multiple equilibria explain?

This paper asks whether the income gap between rich and poor nations can be explained by multiple equilibria. We explore the quantitative implications of a simple two sector general equilibrium model that gives rise to multiplicity, and calibrate the model for a large number of countries. Under the assumptions of the model, around a quarter of the world’s economies are found to be in a low output equilibrium. The output gains associated with an equilibrium switch are sizeable, but well short of the vast income disparity observed in the data.poverty traps, multiple equilibria, TFP differences,calibration

A conjugate gradient minimisation approach to generating holographic traps for ultracold atoms

Direct minimisation of a cost function can in principle provide a versatile and highly controllable route to computational hologram generation. However, to date iterative Fourier transform algorithms have been predominantly used. Here we show that the careful design of cost functions, combined with numerically efficient conjugate gradient minimisation, establishes a practical method for the generation of holograms for a wide range of target light distributions. This results in a guided optimisation process, with a crucial advantage illustrated by the ability to circumvent optical vortex formation during hologram calculation. We demonstrate the implementation of the conjugate gradient method for both discrete and continuous intensity distributions and discuss its applicability to optical trapping of ultracold atoms.Comment: 11 pages, 4 figure