Regional astrocyte IFN signaling restricts pathogenesis during neurotropic viral infection

Type I IFNs promote cellular responses to viruses, and IFN receptor (IFNAR) signaling regulates the responses of endothelial cells of the blood-brain barrier (BBB) during neurotropic viral infection. However, the role of astrocytes in innate immune responses of the BBB during viral infection of the CNS remains to be fully elucidated. Here, we have demonstrated that type I IFNAR signaling in astrocytes regulates BBB permeability and protects the cerebellum from infection and immunopathology. Mice with astrocyte-specific loss of IFNAR signaling showed decreased survival after West Nile virus infection. Accelerated mortality was not due to expanded viral tropism or increased replication. Rather, viral entry increased specifically in the hindbrain of IFNAR-deficient mice, suggesting that IFNAR signaling critically regulates BBB permeability in this brain region. Pattern recognition receptors and IFN-stimulated genes had higher basal and IFN-induced expression in human and mouse cerebellar astrocytes than did cerebral cortical astrocytes, suggesting that IFNAR signaling has brain region–specific roles in CNS immune responses. Taken together, our data identify cerebellar astrocytes as key responders to viral infection and highlight the existence of distinct innate immune programs in astrocytes from evolutionarily disparate regions of the CNS

Using the Internet as a Pleasure Travel Planning Tool: An Examination of the Sociodemographic and Behavioral Characteristics among Internet Users and Nonusers

A critical prerequisite for the formulation of effective travel marketing strategies in the next decade must include an understanding of the influence exerted through the Internet. The increasing presence of the Internet as an instrument for advertising travel destinations and travel-related services highlights its importance as a factor in travelers’ decision-making processes. This exploratory investigation examined travelers who requested on-line information about a potential vacation destination using the Internet. Results of this investigation suggest that Internet “users, when compared with “nonusers,” are more educated, have higher household incomes, use commercial lodging accommodations while traveling, tend to travel by air, and spend more money on travel-related expenses on a per diem basis. Implications for target marketing strategies designed for travel destination areas, services, and facilities are discussed

Predicting a Behavioral Profile for Pleasure Travelers on the Basis of Internet Use Segmentation

In an attempt to create a behavioral profile of pleasure travelers segmented based on Internet use, 5,319 pleasure travelers were interviewed. Initially, the respondents were classified as an Internet user or Internet nonuser based on whether or not they would use the Internet to seek travel related information. Using discriminant analysis, chi square, and analysis of variance statistical techniques, a profile of demographic and behavioral characteristics was created. The results of this study suggest that people who use the Internet to search for travel-related information are likely to be people who are (a) college-educated owners of computers, (b) less than 45 years of age, (c) stay more often in commercial lodging establishments, and (d) spend more money each day while traveling. Implications for marketing managers and future research are discussed

Longitudinal patterns in an Arkansas River Valley stream: an Application of the River Continuum Concept

The River Continuum Concept (RCC) provides the framework for studying how lotic ecosystems vary from headwater streams to large rivers. The RCC was developed in streams in eastern deciduous forests of North America, but watershed characteristics and land uses differ across ecoregions, presenting unique opportunities to study how predictions of the RCC may differ across regions. Additionally, RCC predictions may vary due to the influence of fishes, but few studies have used fish taxa as a metric for evaluating predictions of the RCC. Our goal was to determine if RCC predictions for stream orders 1 through 5 were supported by primary producer, macroinvertebrate, and fish communities in Cadron Creek of the Arkansas River Valley. We sampled chlorophyll a, macroinvertebrates, and fishes at five stream reaches across a gradient of watershed size. Contrary to RCC predictions, chlorophyll a did not increase in concentration with catchment size. As the RCC predicts, fish and macroinvertebrate diversity increased with catchment size. Shredding and collecting macroinvertebrate taxa supported RCC predictions, respectively decreasing and increasing in composition as catchment area increased. Herbivorous and predaceous fish did not follow RCC predictions; however, surface-water column feeding fish were abundant at all sites as predicted. We hypothesize some predictions of the RCC were not supported in headwater reaches of this system due to regional differences in watershed characteristics and altered resource availability due to land use surrounding sampling sites

Coinductive subtyping for abstract compilation of object-oriented languages into Horn formulas

In recent work we have shown how it is possible to define very precise type systems for object-oriented languages by abstractly compiling a program into a Horn formula f. Then type inference amounts to resolving a certain goal w.r.t. the coinductive (that is, the greatest) Herbrand model of f. Type systems defined in this way are idealized, since in the most interesting instantiations both the terms of the coinductive Herbrand universe and goal derivations cannot be finitely represented. However, sound and quite expressive approximations can be implemented by considering only regular terms and derivations. In doing so, it is essential to introduce a proper subtyping relation formalizing the notion of approximation between types. In this paper we study a subtyping relation on coinductive terms built on union and object type constructors. We define an interpretation of types as set of values induced by a quite intuitive relation of membership of values to types, and prove that the definition of subtyping is sound w.r.t. subset inclusion between type interpretations. The proof of soundness has allowed us to simplify the notion of contractive derivation and to discover that the previously given definition of subtyping did not cover all possible representations of the empty type

Ant colonies: building complex organizations with minuscule brains and no leaders

Thus far the articles in the series JOD calls the “Organization Zoo” have employed the notion of a “zoo” metaphorically to describe an array of human institutions. Here we take the term literally to consider the design of the most complex organizations in the living world beside those of humans, a favorite of insect zoos around the world: ant colonies. We consider individuality and group identity in the functioning of ant organizations; advantages of a flat organization without hierarchies or leaders; self-organization; direct and indirect communication; job specialization; labor coordination; and the role of errors in innovation. The likely value and limitations of comparing ant and human organizations are briefly examined

Racial and gender science achievement gaps in secondary education

ABSTRACT A substantial disparity exists for academic achievement in science between Black and White primary-school children. A similar gap exists between boys and girls. The extent to which secondary education influences these achievement gaps has not been established. The authors report analyses showing how these science achievement gaps change as a function of secondary education. Analyses of data from a large, nationally representative longitudinal study of academic achievement showed that racial disparities and disparities associated with gender continue to increase throughout high school