Traversing non-convex regions

This paper considers a method for dealing with non-convex objective functions in optimization problems. It uses the Hessian matrix and combines features of trust-region techniques and continuous steepest descent trajectory-following in order to construct an algorithm which performs curvilinear searches away from the starting point of each iteration. A prototype implementation yields promising resultsPeer reviewe

Contening cultures amongst development actors

Lewis et al (2003) establish a cogent argument which suggests that serious analysis of the culture of aid organizations, and of the relationships with other actors, matters, and that it is a neglected area of analysis. Their discussion raises important new questions about the development enterprise from an internal perspective that heretofore has been neglected or ignored. Contrasting the article by Lewis et al. with a book by Harrison and Huntington (2000) reinforces that conviction. Throughout the Harrison and Huntington book-- whose authors provide an excellent overview of the history of the study of culture as something that certainly does ‘matter’ in development--we kept saying to ourselves that ‘All this is fine, but it is focussed (as is much of the ancillary literature on ‘culture’ in development) on looking outward, at others undergoing development, without consideration of the development agency actors themselves. It mostly addresses questions and issues concerning the question: Why some political and national systems succeed and others fail

Who should be searching? Differences in personality can affect visual search accuracy

© 2017 Visual search is an everyday task conducted in a wide variety of contexts. Some searches are mundane, such as finding a beverage in the refrigerator, and some have life-or-death consequences, such as finding improvised explosives at a security checkpoint or within a combat zone. Prior work has shown numerous influences on search, including “bottom-up” (physical stimulus attributes) and “top-down” factors (task-relevant or goal-driven aspects). Recent work has begun to focus on “observer-specific” factors, examining how searchers' attributes might influence search performance. A logical extension involves exploring whether some individuals are better suited to conduct visual searches than other individuals. The current study examined whether certain personality characteristics relate to visual search performance in a large sample of professional searchers employed by the U.S. Transportation Security Administration. Of the “big five” personality traits (neuroticism, extroversion, openness, agreeableness, and conscientiousness), only conscientiousness significantly correlated with visual search accuracy. Both early-career and experienced professional searchers demonstrated a significant relationship between conscientiousness scores and accuracy on a simple visual search task. These findings validate the notion that searchers' attributes impact their visual search performance and suggest that personality assessments might prove useful for hiring and selection decisions regarding professional tasks that incorporate visual search

A new VLA/e-MERLIN limit on central images in the gravitational lens system CLASS B1030+074

We present new VLA 22-GHz and e-MERLIN 5-GHz observations of CLASS B1030+074, a two-image strong gravitational lens system whose background source is a compact flat-spectrum radio quasar. In such systems we expect a third image of the background source to form close to the centre of the lensing galaxy. The existence and brightness of such images is important for investigation of the central mass distributions of lensing galaxies, but only one secure detection has been made so far in a galaxy-scale lens system. The noise levels achieved in our new B1030+074 images reach 3 microJy/beam and represent an improvement in central image constraints of nearly an order of magnitude over previous work, with correspondingly better resulting limits on the shape of the central mass profile of the lensing galaxy. Simple models with an isothermal outer power law slope now require either the influence of a central supermassive black hole, or an inner power law slope very close to isothermal, in order to suppress the central image below our detection limit. Using the central mass profiles inferred from light distributions in Virgo galaxies, moved to z=0.5, and matching to the observed Einstein radius, we now find that 45% of such mass profiles should give observable central images, 10% should give central images with a flux density still below our limit, and the remaining systems have extreme demagnification produced by the central SMBH. Further observations of similar objects will therefore allow proper statistical constraints to be placed on the central properties of elliptical galaxies at high redshift.Comment: Accepted by Monthly Notices of the Royal Astronomical Society. 16 pages, 8 figure

Stimulation of the Pro-Resolving Receptor Fpr2 Reverses Inflammatory Microglial Activity by Suppressing NFκB Activity

Neuroinflammation driven primarily by microglia directly contributes to neuronal death in many neurodegenerative diseases. Classical anti-inflammatory approaches aim to suppress pro-inflammatory mediator production, but exploitation of inflammatory resolution may also be of benefit. A key driver of peripheral inflammatory resolution, formyl peptide receptor 2 (Fpr2), is expressed by microglia, but its therapeutic potential in neurodegeneration remains unclear. Here, we studied whether targeting of Fpr2 could reverse inflammatory microglial activation induced by the potent bacterial inflammogen lipopolysaccharide (LPS). Exposure of murine primary or immortalised BV2 microglia to LPS triggered pro-inflammatory phenotypic change and activation of ROS production, effects significantly attenuated by subsequent treatment with the Fpr2 agonist C43. Mechanistic studies showed C43 to act through p38 MAPK phosphorylation and reduction of LPS-induced NFκB nuclear translocation via prevention of IκBα degradation. Here, we provide proof-of-concept data highlighting Fpr2 as a potential target for control of microglial pro-inflammatory activity, suggesting that it may be a promising therapeutic target for the treatment of neuroinflammatory disease