University of Minnesota

About: University of Minnesota is a education organization based out in Minneapolis, Minnesota, United States. It is known for research contribution in the topics: Population & Transplantation. The organization has 117432 authors who have published 257986 publications receiving 11944239 citations. The organization is also known as: University of Minnesota, Twin Cities & University of Minnesota-Twin Cities.

The new Casper: query processing for location services without compromising privacy

Abstract: This paper tackles a major privacy concern in current location-based services where users have to continuously report their locations to the database server in order to obtain the service. For example, a user asking about the nearest gas station has to report her exact location. With untrusted servers, reporting the location information may lead to several privacy threats. In this paper, we present Casper1; a new framework in which mobile and stationary users can entertain location-based services without revealing their location information. Casper consists of two main components, the location anonymizer and the privacy-aware query processor. The location anonymizer blurs the users' exact location information into cloaked spatial regions based on user-specified privacy requirements. The privacy-aware query processor is embedded inside the location-based database server in order to deal with the cloaked spatial areas rather than the exact location information. Experimental results show that Casper achieves high quality location-based services while providing anonymity for both data and queries.

Plant diversity and ecosystem productivity: theoretical considerations.

Abstract: Ecosystem processes are thought to depend on both the number and identity of the species present in an ecosystem, but mathematical theory predicting this has been lacking. Here we present three simple models of interspecific competitive interactions in communities containing various numbers of randomly chosen species. All three models predict that, on average, productivity increases asymptotically with the original biodiversity of a community. The two models that address plant nutrient competition also predict that ecosystem nutrient retention increases with biodiversity and that the effects of biodiversity on productivity and nutrient retention increase with interspecific differences in resource requirements. All three models show that both species identity and biodiversity simultaneously influence ecosystem functioning, but their relative importance varies greatly among the models. This theory reinforces recent experimental results and shows that effects of biodiversity on ecosystem functioning are predicted by well-known ecological processes.

Regulation of TORC1 by Rag GTPases in nutrient response.

Abstract: TORC1 (target of rapamycin complex 1) has a crucial role in the regulation of cell growth and size. A wide range of signals, including amino acids, is known to activate TORC1. Here, we report the identification of Rag GTPases as activators of TORC1 in response to amino acid signals. Knockdown of Rag gene expression suppressed the stimulatory effect of amino acids on TORC1 in Drosophila melanogaster S2 cells. Expression of constitutively active (GTP-bound) Rag in mammalian cells activated TORC1 in the absence of amino acids, whereas expression of dominant-negative Rag blocked the stimulatory effects of amino acids on TORC1. Genetic studies in Drosophila also show that Rag GTPases regulate cell growth, autophagy and animal viability during starvation. Our studies establish a function of Rag GTPases in TORC1 activation in response to amino acid signals.

Moving into adolescence: The impact of pubertal change and school context.

Abstract: From the sociological point of view, adolescence traditionally has been described as a period of physical maturity and social immaturity. Adolescents reach physical adulthood before they are capable of functioning well in adult social roles. The disjunction between physical capabilities and socially allowed independence and power and the concurrent status ambiguities are viewed as stressful for the adolescent in modern Western society. It has been assumed that the need to disengage from parents during these years will result in high levels of rebellion and parent-child confl ict. Moving into Adolescence follows students as they make a major life course transition from childhood into early adolescence.

A Capabilities Perspective on the Effects of Early Internationalization on Firm Survival and Growth

Abstract: Recent critiques of internationalization process models question the wisdom of delaying internationalization. Internationalizing late allows firms to assemble resources and gain experience but also allows inertia to develop. We resolve this tension by positing that internationalization has differing effects on firm survival and growth. These effects are moderated by organizational age, managerial experience, and resource fungibility. Our framework provides insights into the evolution of capabilities across borders and may be tested and built upon by organization researchers.