Supervised Associative Learning in Spiking Neural Network

In this paper, we propose a simple supervised associative learning approach for spiking neural networks. In an excitatory-inhibitory network paradigm with Izhikevich spiking neurons, synaptic plasticity is implemented on excitatory to excitatory synapses dependent on both spike emission rates and spike timings. As results of learning, the network is able to associate not just familiar stimuli but also novel stimuli observed through synchronised activity within the same subpopulation and between two associated subpopulations

Review of NGO performance research published in academic journals between 1996 and 2008

Globally, literature on the performance of development non-governmental organisations (NGOs) has increased. However, little is known regarding the distinctive characteristics of academic articles on factors influencing NGO performance. In a recent systematic review of research, published in English-language academic journals between 1996 and 2008, factors influencing NGO performance were investigated. From the 31 journal articles that met the inclusion criteria, this study examined the salient characteristics of NGO performance research in terms of, (1) the number of publications, (2) publication outlets (journals and journal cluster), (3) author collaboration (sole or joint authors), (4) author affiliation, (5) study location, (6) study period, (7) study topics and (8) method and sources of information. Findings showed a steady increase in the number of articles, published in a wide array of journals with over half of the articles published in development studies journals. Of the 31 articles, 21 were sole authored. Data were mainly sought from NGO directors, programme staff and donors; comparatively fewer studies collected data from beneficiaries. Studies were mainly conducted in developing countries, whilst most authors were affiliated to institutions in developed countries. Of the 13 authors who conducted studies in Africa only 3 were affiliated to an institution in Africa. This study confirmed the continued need for increased research on factors influencing NGO performance; revealed the low seeking of beneficiaries’ perspectives in NGO performance research despite the rhetoric of participatory development; and revealed the low number of published researchers in Africa an

UK export performance research - review and implications

Previous research on export performance has been criticized for being a mosaic of autonomous endeavours and for a lack of theoretical development. Building upon extant models of export performance, and a review and analysis of research on export performance in the UK for the period 1990-2005, an integrated model of export performance is developed and theoretical explanations of export performance are put forward. It is suggested that a multi-theory approach to explaining export performance is viable. Management and policy implications for the UK emerging from the review and synthesis of the literature and the integrated model are discussed

Rheology of Active-Particle Suspensions

We study the interplay of activity, order and flow through a set of coarse-grained equations governing the hydrodynamic velocity, concentration and stress fields in a suspension of active, energy-dissipating particles. We make several predictions for the rheology of such systems, which can be tested on bacterial suspensions, cell extracts with motors and filaments, or artificial machines in a fluid. The phenomena of cytoplasmic streaming, elastotaxis and active mechanosensing find natural explanations within our model.Comment: 3 eps figures, submitted to Phys Rev Let

Development of a district mental healthcare plan in Uganda.

BACKGROUND: Evidence is needed for the integration of mental health into primary care advocated by the national health sector strategic investment plan in Uganda. AIMS: To describe the processes of developing a district mental healthcare plan (MHCP) in rural Uganda that facilitates integration of mental health into primary care. METHOD: Mixed methods using a situational analysis, qualitative studies, theory of change workshops and partial piloting of the plan at two levels informed the MHCP. RESULTS: A MHCP was developed with packages of care to facilitate integration at the organisational, facility and community levels of the district health system, including a specified human resource mix. The partial embedding period supports its practical application. Key barriers to scaling up the plan were identified. CONCLUSIONS: A real-world plan for the district was developed with involvement of stakeholders. Pilot testing demonstrated its feasibility and implications for future scaling up

Children’s friendships in middle childhood: how number of friends, reciprocity and friendship quality relate to peer and school identification, and general self-worth

Children’s friendships are important for well-being and school adjustment, but few studies have examined multiple indices of friendships together in middle childhood. The current study surveyed 7 to 11-year olds (n = 314) about their friendships, best friendships, friendship quality and indices of self-worth, identification with peers and identification with school. Peer relationships were positively related to self-worth, but not identification with peers or school. Best friendship quality moderated the relationship between number of reciprocated friendship nominations and self-worth. Children with a reciprocated best friend had higher friendship quality and peer identification than others. Where best friendship was reciprocated, the relationship with identification with peers was mediated via positive friendship quality. The results suggest that friendship reciprocity is particularly relevant for children’s self-worth and identification with peers. The findings are discussed in relation to the importance of fostering the development of reciprocated friendships

Electronic and phononic properties of cinnabar: ab initio calculations and some experimental results

We report ab initio calculations of the electronic band structure, the corresponding optical spectra, and the phonon dispersion relations of trigonal alpha-HgS (cinnabar). The calculated dielectric functions are compared with unpublished optical measurements by Zallen and coworkers. The phonon dispersion relations are used to calculate the temperature and isotopic mass dependence of the specific heat which has been compared with experimental data obtained on samples with the natural isotope abundances of the elements Hg and S (natural minerals and vapor phase grown samples) and on samples prepared from isotope enriched elements by vapor phase transport. Comparison of the calculated vibrational frequencies with Raman and ir data is also presented. Contrary to the case of cubic beta-HgS (metacinnabar), the spin-orbit splitting of the top valence bands at the Gamma-point of the Brillouin zone (Delta_0) is positive, because of a smaller admixture of 5d core electrons of Hg. Calculations of the lattice parameters, and the pressure dependence of Delta_0 and the corresponding direct gap E_0~2eV are also presented. The lowest absorption edge is confirmed to be indirect.Comment: 13 pages, 15 figure

'Word from the street' : when non-electoral representative claims meet electoral representation in the United Kingdom

Taking the specific case of street protests in the UK – the ‘word from the street’– this article examines recent (re)conceptualizations of political representation, most particularly Saward’s notion of ‘representative claim’. The specific example of nonelectoral claims articulated by protestors and demonstrators in the UK is used to illustrate: the processes of making, constituting, evaluating and accepting claims for and by constituencies and audiences; and the continuing distinctiveness of claims based upon electoral representation. Two basic questions structure the analysis: first, why would the political representative claims of elected representatives trump the nonelectoral claims of mass demonstrators and, second, in what ways does the ‘perceived legitimacy’ of the former differ from the latter

Vacuum assisted closure in coloproctology

Vacuum-assisted closure has earned its indications in coloproctology. It has been described with variable results in the treatment of large perineal defects after abdominoperineal excision, in the treatment of stoma dehiscence and perirectal abscesses. The most promising indication for vacuum-assisted closure is probably the treatment of para-anastomotic presacral abscesses following anastomotic leakage after total mesorectal excision. Early initiation of vacuum-assisted closure has the potential to prevent debilitating persistent presacral sinuses precluding stoma closure and bad function of the neorectum. Prompt initiation of endosponge treatment is advised after the anastomotic leakage with the purulent cavity is diagnosed. The endosponge is inserted transanally and connected with a low vacuum bottle. With the gradual reduction in the cavity, the endosponge is reduced in size every 3–4 days when the endosponge is exchanged. It takes 3–6 weeks to close the cavity. Future studies should focus on the stoma closure rate and function to assess whether this intensive postoperative treatment of anastomotic leakages is justified

Conformations of Linear DNA

We examine the conformations of a model for under- and overwound DNA. The molecule is represented as a cylindrically symmetric elastic string subjected to a stretching force and to constraints corresponding to a specification of the link number. We derive a fundamental relation between the Euler angles that describe the curve and the topological linking number. Analytical expressions for the spatial configurations of the molecule in the infinite- length limit were obtained. A unique configuraion minimizes the energy for a given set of physical conditions. An elastic model incorporating thermal fluctuations provides excellent agreement with experimental results on the plectonemic transition.Comment: 5 pages, RevTeX; 6 postscript figure