Diversity and Dynamics of Indigenous \u3cem\u3eRhizobium japonicum\u3c/em\u3e Populations

A simple method, based upon the separation of cellular proteins by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, has been devised for distinguishing between isolates of Rhizobium japonicum. Eleven laboratory strains, previously classified into five serogroups, were analyzed by gel electrophoresis. Groups determined subjectively according to protein patterns matched the serogroups, with one exception. Most strains within serogroups could be distinguished from one another. For studying the ecology of Rhizobium, an important advantage of this technique compared with serology or phage typing is that it discriminates among previously unencountered indigenous bacterial isolates as well as among known laboratory strains. SDS-gels were used to analyze the Rhizobium population of 500 nodules, sampled throughout the growing season, from soybeans at two different Wisconsin localities. Although the soybeans had been inoculated with laboratory strains of R. japonicum, indigenous R. japonicum predominated. At one location, 19 indigenous gel types were distinguished and classified mainly into four groups. At the other location, 18 gel types, falling mainly into three groups, were detected. The predominance of a particular group varied, in some cases dramatically, depending upon the time and depth of nodule formation

Canonical Analysis of Algebraic String Actions

We investigate the canonical aspects of the algebraic first order formulation of strings introduced two decades ago by Balachandran and collaborators. We slightly enlarge the Lagrangian framework and show the existence of a self-dual formulation and of an Immirzi-type parameter reminiscent of four-dimensional first order gravity. We perform a full Hamiltonian analysis of the self-dual case: we extract the first class constraints and construct the Dirac bracket associated to the second class constraints. The first class constraints contain the diffeomorphisms algebra on the world-sheet, and the coordinates are shown to be non-commutative with respect to the Dirac bracket. The Hamilton equations in a particular gauge are shown to reproduce the wave equation for the string coordinates. In the general, non-self-dual case, we also explicit the first class constraints of the system and show that, unlike the self-dual formulation, the theory admits an extra propagating degree of freedom than the two degrees of freedom of conventional string theory. This prevents the general algebraic string from being strictly equivalent to the Nambu-Goto string.Comment: Title changed. Presentation improved. Typos correcte

Peer Effects in Higher Education

In this chapter, we describe the potential significance of student peer effects for the economic structure of and behavior in higher education. Their existence would motivate much of the restricted supply, student queuing, and selectivity and institutional competition via merit aid and honors colleges that we see in American higher education; their (appropriate) non-linearity could justify the resulting stratification of higher education as an efficient way to produce human capital. In addition, we use data from the College and Beyond entering class of 1989, combined with phonebook data identifying roommates, to implement a quasi-experimental empirical strategy aimed at measuring peer effects in academic outcomes. In particular, we use data on individual students' grades, SAT scores, and the SAT scores of their roommates at three schools to estimate the effect of roommates' academic characteristics on an individual's grades. The results suggest that, for two of the three schools used, students in the middle of the SAT distribution do somewhat worse in terms of grades if they share a room with a student who is in the bottom 15 percent of the SAT distribution. Students in the top of the SAT distribution appear often not to be affected by the SAT scores of their roommates. These results are similar to those reported in earlier research using data from Williams (Zimmerman) and Dartmouth (Sacerdote).

Guardian Knight or Hands Off: The European Response to Network Neutrality. Legal considerations on the electronic communications reform

Network neutrality refers to a policy principle regarding access for online content and service providers to broadband infrastructures. It implies a general and ex ante obligation of non-discrimination for network operators when granting access to providers of online services, with the aim of excluding practices such as blocking access to non-affiliated content, degrading the quality of transmission, imposing unreasonable restrictions or prioritising affiliated content. Whether such obligation should be "cast in the Stone Tables" of the law was first fiercely debated in the United States, and the issue is now gaining increased attention in other parts of the world, including the European Union, where the regulatory framework for electronic communications is currently under review. This article examines whether existing rules already provide the relevant authorities with the necessary tools to take action against broadband providers illegitimately discriminating or blocking content of those who are not prepared to pay a "toll" for the use of higher speed networks or better quality services. It focuses in particular on the EU regulatory framework for electronic communications networks and services, including the reform proposals published by the European Commission on November 13th (type should be like 24th below) 2007 and the resolution adopted by the European Parliament on 24th September 2008.network neutrality, regulation, electronic communications, reform proposals.

The FCC's Network Neutrality Ruling in the Comcast Case: Towards a Consensus with Europe?

In August 2008, the FCC found that Comcast's restrictions on peer-to-peer upload transmissions were unreasonably discriminatory, arbitrarily targeted a particular application, and deprived consumers of their rights to run Internet applications and use services of their choice. The Comcast ruling represents a significant change in the FCC's direction: given the FCC's past decisions that broadband Internet access services do not fall within the "common carrier" category, it is notable that the agency has now imposed nondiscrimination requirements on these services. This Article shows that the rationales articulated in the FCC's Comcast order, stressing both (i) concerns about protecting competition and (ii) concerns about protecting consumers from disruption of their ability to communicate freely and privately, are rooted in centuries of Anglo-American law defining he obligations of "common carriers." The FCC appears to be moving away from its traditional emphasis on the competition policy concerns, which justify asymmetrical regulation of dominant providers for the sake of enabling competition, and toward an emphasis on the consumer protection issues, which justify symmetrical regulation of all service providers regardless whether they have market power. These developments in the U.S. echo the discussion now going on in Europe in the context of the package of proposals on a new common regulatory framework for telecommunications, released by the European Commission on Nov. 13, 2007, and which is now being debated by the European Parliament and Council. On both sides of the Atlantic, a trend is emerging to permit network discrimination only if the discrimination is narrowly tailored to achieve legitimate objectives.network neutrality, discrimination, common carrier, network management, Comcast, European Directives.

Evaluation of capacitors for space propulsion applications final progress report

Low inductance energy storage capacitors for space propulsion application

What is a Good Plan? Cultural Variations in Expert Planners’ Concepts of Plan Quality

This article presents the results of a field research study examining commonalities and differences between American and British operational planners’ mental models of planning. We conducted Cultural Network Analysis (CNA) interviews with 14 experienced operational planners in the US and UK. Our results demonstrate the existence of fundamental differences between the way American and British expert planners conceive of a high quality plan. Our results revealed that the American planners’ model focused on specification of action to achieve synchronization, providing little autonomy at the level of execution, and included the belief that increasing contingencies reduces risk. The British planners’ model stressed the internal coherence of the plan, to support shared situational awareness and thereby flexibility at the level of execution. The British model also emphasized the belief that reducing the number of assumptions decreases risk. Overall, the American ideal plan serves a controlling function, whereas the British ideal plan supports an enabling function. Interestingly, both the US and UK would view the other’s ideal plan as riskier than their own. The implications of cultural models of plans and planning are described for establishing performance measures and designing systems to support multinational planning teams