Gap Filling of 3-D Microvascular Networks by Tensor Voting

We present a new algorithm which merges discontinuities in 3-D images of tubular structures presenting undesirable gaps. The application of the proposed method is mainly associated to large 3-D images of microvascular networks. In order to recover the real network topology, we need to fill the gaps between the closest discontinuous vessels. The algorithm presented in this paper aims at achieving this goal. This algorithm is based on the skeletonization of the segmented network followed by a tensor voting method. It permits to merge the most common kinds of discontinuities found in microvascular networks. It is robust, easy to use, and relatively fast. The microvascular network images were obtained using synchrotron tomography imaging at the European Synchrotron Radiation Facility. These images exhibit samples of intracortical networks. Representative results are illustrated

Transfer of Metacognitive Skills and Hint Seeking in Monkeys

Metacognition is knowledge that can be expressed as confidence judgments about what we know (monitoring) and by strategies for learning what we don’t know (control). Although a substantial literature exists on cognitive processes in animals, little is known about their metacognitive abilities. Here we show that rhesus macaques, trained previously to make retrospective confidence judgments about their performance on perceptual tasks, transferred that ability immediately to a new perceptual task and to a working memory task. In a second experiment we show that monkeys can also learn to request “hints” when they are given problems that they would otherwise have to solve by trial and error. This shows, for the first time, that non-human primates share with humans the ability to monitor and transfer their metacognitive ability both within and between different cognitive tasks, and to seek new knowledge on a need to know basis.

A Labelled Analytic Theorem Proving Environment for Categorial Grammar

We present a system for the investigation of computational properties of categorial grammar parsing based on a labelled analytic tableaux theorem prover. This proof method allows us to take a modular approach, in which the basic grammar can be kept constant, while a range of categorial calculi can be captured by assigning different properties to the labelling algebra. The theorem proving strategy is particularly well suited to the treatment of categorial grammar, because it allows us to distribute the computational cost between the algorithm which deals with the grammatical types and the algebraic checker which constrains the derivation.Comment: 11 pages, LaTeX2e, uses examples.sty and a4wide.st

Learning from Analysis of Japanese EFL Texts

Japan has a long tradition of teaching English as a foreign language (EFL). A common feature of EFL courses is reliance on specific textbooks as a basis for graded teaching, and periods in Japanese EFL history are marked by the introduction of different textbook series. These sets of textbooks share the common goal of taking students from beginners through to able English language users, so one would expect to find common characteristics across such series. As part of an on-going research programme in which Japanese EFL textbooks from different historical periods are compared and contrasted, we have recently focussed our efforts on using textual analysis tools to highlight distinctive characteristics of such textbooks. The present paper introduces one such analysis tool and describes some of the results from its application to three textbook series from distinct periods in Japanese EFL history. In so doing, we aim to encourage the use of textual analysis and seek to expose salient features of EFL texts which would likely remain hidden without such analytical techniques

measures of social capital and trust

Trust and trustworthiness are important components of social capital and much attention has been devoted to the problems of their correct evaluation. Attitudinal survey questions as reported in the EVS – European Value Survey - are often regarded as inefficient indicators of trust, since they lack of behavioural underpinnings (Putnam, 1995) which one might desire when measuring trust. In this paper, we consider alternative measures of trust and trustworthiness, based on behavioural assumptions. We construct two relative behavioural measures of trust (RBM1 and RBM2), both based on the ex post measurement of trust, once individuals are informed on the level of trustworthiness of the social group to which they have been allocated during the experiment. Our main finding is that the relative behavioural measures show that trust strongly varies once the individual is informed on the on the level of trustworthiness of the social group to which he\she has been allocated during the experiment. This difference is higher the higher is the family level of income and the parental education status. As for previous findings (Glaeser et al., 2000, Lazzarini, 2005) which have found no correlation between attitudinal and behavioural measures of trust, we find that relative behavioural measures are not correlated to attitudinal measures but they are strongly correlated to groups’ trustworthiness. We also find that similar social preferences profiles (between Senders and Recipients) tend to enhance the individual level of trust, in the RBM2 context. This result seems to confirm the importance of the homogeneity of the social environment when studying the effects of policy interventions (Alesina and La Ferrara, 2002).social capital, trust, experiments