Self-Employment of Immigrants: A Cross-National Study of 17 Western Societies

This study examines the role of immigrants’ country of origin, country of destination and combinations thereof (settings or communities) in the likelihood of immigrants being selfemployed. I pooled census data from three classic immigrant countries (Australia, Canada and the United States) and labor-force surveys from 14 countries in the European Union for a cross-national data set. Using multilevel techniques, I find that (1) immigrants from non-Christian countries of origin have higher odds of self-employment, (2) higher levels of unemployment among natives increase the odds of self-employment, and (3) selfemployment is more frequent among immigrant communities that are small, highly educated and have a longer settlement history.

Neural blackboard architectures of combinatorial structures in cognition

Human cognition is unique in the way in which it relies on combinatorial (or compositional) structures. Language provides ample evidence for the existence of combinatorial structures, but they can also be found in visual cognition. To understand the neural basis of human cognition, it is therefore essential to understand how combinatorial structures can be instantiated in neural terms. In his recent book on the foundations of language, Jackendoff described four fundamental problems for a neural instantiation of combinatorial structures: the massiveness of the binding problem, the problem of 2, the problem of variables and the transformation of combinatorial structures from working memory to long-term memory. This paper aims to show that these problems can be solved by means of neural ‘blackboard’ architectures. For this purpose, a neural blackboard architecture for sentence structure is presented. In this architecture, neural structures that encode for words are temporarily bound in a manner that preserves the structure of the sentence. It is shown that the architecture solves the four problems presented by Jackendoff. The ability of the architecture to instantiate sentence structures is illustrated with examples of sentence complexity observed in human language performance. Similarities exist between the architecture for sentence structure and blackboard architectures for combinatorial structures in visual cognition, derived from the structure of the visual cortex. These architectures are briefly discussed, together with an example of a combinatorial structure in which the blackboard architectures for language and vision are combined. In this way, the architecture for language is grounded in perception

Measuring the Virial Masses of Disk Galaxies

I present detailed models for the formation of disk galaxies, and investigate which observables are best suited as virial mass estimators. Contrary to naive expectations, the luminosities and circular velocities of disk galaxies are extremely poor indicators of total virial mass. Instead, I show that the product of disk scale length and rotation velocity squared yields a much more robust estimate. Finally, I show how this estimator may be used to put limits on the efficiencies of cooling and feedback during the process of galaxy formation.Comment: 6 pages, 2 fig. To appear in proceedings of "The Mass of Galaxies at Low and High Redshift", eds. R. Bender and A. Renzini (ESO Astrophysics Symposia, Springer-Verlag

Talking Nets: A Multi-Agent Connectionist Approach to Communication and Trust between Individuals

A multi-agent connectionist model is proposed that consists of a collection of individual recurrent networks that communicate with each other, and as such is a network of networks. The individual recurrent networks simulate the process of information uptake, integration and memorization within individual agents, while the communication of beliefs and opinions between agents is propagated along connections between the individual networks. A crucial aspect in belief updating based on information from other agents is the trust in the information provided. In the model, trust is determined by the consistency with the receiving agents’ existing beliefs, and results in changes of the connections between individual networks, called trust weights. Thus activation spreading and weight change between individual networks is analogous to standard connectionist processes, although trust weights take a specific function. Specifically, they lead to a selective propagation and thus filtering out of less reliable information, and they implement Grice’s (1975) maxims of quality and quantity in communication. The unique contribution of communicative mechanisms beyond intra-personal processing of individual networks was explored in simulations of key phenomena involving persuasive communication and polarization, lexical acquisition, spreading of stereotypes and rumors, and a lack of sharing unique information in group decisions

Destination-Language Proficiency in Cross-National Perspective: A Study of Immigrant Groups in Nine Western Countries

Immigrants’ destination-language proficiency has been typically studied from a microperspective in a single country. In this article, the authors examine the role of macrofactors in a cross-national perspective. They argue that three groups of macrolevel factors are important: the country immigrants settle in (“destination” effect), the sending nation (“origin” effect), and the combination between origin and destination (“setting” or “community” effect). The authors propose a design that simultaneously observes multiple origin groups in multiple destinations. They present substantive hypotheses about language proficiency and use them to develop a series of macrolevel indicators. The authors collected and standardized 19 existing immigrant surveys for nine Western countries. Using multilevel techniques, their analyses show that origins, destinations, and settings play a significant role in immigrants’ language proficiency.