Origin of synchronized traffic flow on highways and its dynamic phase transitions

We study the traffic flow on a highway with ramps through numerical simulations of a hydrodynamic traffic flow model. It is found that the presence of the external vehicle flux through ramps generates a new state of recurring humps (RH). This novel dynamic state is characterized by temporal oscillations of the vehicle density and velocity which are localized near ramps, and found to be the origin of the synchronized traffic flow reported recently [PRL 79, 4030 (1997)]. We also argue that the dynamic phase transitions between the free flow and the RH state can be interpreted as a subcritical Hopf bifurcation.Comment: 4 pages, source TeX file and 4 figures are tarred and compressed via uufile

An agent-based dynamic information network for supply chain management

One of the main research issues in supply chain management is to improve the global efficiency of supply chains. However, the improvement efforts often fail because supply chains are complex, are subject to frequent changes, and collaboration and information sharing in the supply chains are often infeasible. This paper presents a practical collaboration framework for supply chain management wherein multi-agent systems form dynamic information networks and coordinate their production and order planning according to synchronized estimation of market demands. In the framework, agents employ an iterative relaxation contract net protocol to find the most desirable suppliers by using data envelopment analysis. Furthermore, the chain of buyers and suppliers, from the end markets to raw material suppliers, form dynamic information networks for synchronized planning. This paper presents an agent-based dynamic information network for supply chain management and discusses the associated pros and cons

Optimal Estimates for the Electric Field in Two-Dimensions

The purpose of this paper is to set out optimal gradient estimates for solutions to the isotropic conductivity problem in the presence of adjacent conductivity inclusions as the distance between the inclusions goes to zero and their conductivities degenerate. This difficult question arises in the study of composite media. Frequently in composites, the inclusions are very closely spaced and may even touch. It is quite important from a practical point of view to know whether the electric field (the gradient of the potential) can be arbitrarily large as the inclusions get closer to each other or to the boundary of the background medium. In this paper, we establish both upper and lower bounds on the electric field in the case where two circular conductivity inclusions are very close but not touching. We also obtain such bounds when a circular inclusion is very close to the boundary of a circular domain which contains the inclusion. The novelty of these estimates, which improve and make complete our earlier results published in Math. Ann., is that they give an optimal information about the blow-up of the electric field as the conductivities of the inclusions degenerate.Comment: 26 page

Characteristics of Alveolar Bone Marrow Cells from Patients Undergoing Dental Extractions or Dental Implant Therapy

Alveolar bone marrow stromal cells (aBMSCs) play important roles in craniofacial wound healing. To establish an easy, efficient and reliable method to harvest aBMSCs, we compared three different methods: extraction socket aspiration, osteotomy aspiration and bone core digestion. Samples of aBMSC were collected from two groups of subjects. Group 1 (dental extraction): after dental extraction, 22.5-gauge needles were used to collect 0.5-1cc marrow aspirate. Group 2 (dental implant): during implant surgeries, bone core and 0.5-1cc marrow aspirate were obtained from the osteotomy. Samples were cultured in petri dishes and attached cells were expanded. The population doubling time (PDT), surface markers, and osteogenic differentiation potential of these cells were studied. In total 12 subjects were enrolled in the study. The success rates of generating aBMSCs from extraction socket aspiration, osteotomy aspiration and bone core digestion were 42.8% (3/7), 40% (2/5) and 80% (4/5), respectively. Cells from extraction socket aspiration had the fastest proliferation rate among the three sample types, followed by bone core and osteotomy aspiration, as shown in PDTs and DNA fold changes. After isolation and expansion, all the aBMSCs expressed high levels of CD 73, CD90, and CD105, however, the expression of CD146 varied among the cells. Cells derived from bone core had the highest ALP activity after osteogenic induction, followed by cells from osteotomy aspiration, and then extraction aspiration. Taken together, bone core samples obtained during implant surgery is a more reliable source for generating aBMSCs and aBMSCs harvested from different methods may have different characteristics

Safe-Conduct Theory of the Alien Tort Statute, The

In this Article, Professor Lee introduces a novel explanation of the Alien Tort Statute (ATS) - a founding-era enactment that has achieved modern prominence as a vehicle for international human rights litigation. He demonstrates how the statute was intended to address violations of something called a safe conduct - a sovereign promise of safety to aliens from injury to their persons and property. The safe-conduct theory advances a new modern role for the ATS to redress torts committed by private actors - including aliens - with a U.S. sovereign nexus, and not for international law violations committed by anyone anywhere. In developing this contextual account, Professor Lee resolves uncertainty over the constitutional basis for the ATS and shows how, even with sparse conventional sources, the original meaning of an iconic founding-era statute might be recovered

New York’s School Teachers Say No to the Status Quo! A Chronicle of New York State’s Teachers Union’s (NYSUT) First Contested Election

Other than a scattered mentioning on educational blogs, and a few uninspired national references, the New York State United Teacher’s (NYSUT) April 2014 first contested election in its four decade history did not seem to matter very much. We saw it differently at Cornell’s ILR School. NYSUT is known as a highly efficient, top down, union powerhouse, yet we learned that this election saw school teachers and their local union leaders utilizing their organization’s design and structure for the members’ advantage in a stunning “bottom up” political victory. This surprising outcome is why we decided to research how this occurred and write this report. Along the way, we met brilliant strategists, courageous political novitiates, remarkable communication specialists, and never-ending tenacity wrapped in purposefulness that ensured school-based leaders their electoral success. In doing so, they joined their insurgent teacher colleagues in Massachusetts, Milwaukee, Chicago, Los Angeles, St. Paul and elsewhere, affirming that school teacher trade unionists can and will respond to the attacks upon them and public education. The following pages chart why this contested election occurred and how the insurgents proceeded. The information is based primarily upon extensive interviews with rank and file leaders and discussions with former and newly elected leaders. There are also specific references to observations shared by the defeated President, Richard Iannuzzi, who graciously offered his candor in explaining how he saw what was happening to the union and why he acted as he did in the period leading up to his defeat. This report begins with some brief comments about NYSUT’s history, placement of the election in both a national and New York state context, and an explanation about how NYSUT’s structure had so much to do with the election. The bulk of the writing describes how rank and file forces slowly but molecularly developed into a force able to successfully challenge the president and leadership team of the largest state union in America. Throughout, the detail presented suggests that power wielded by rank and file union members of the teaching profession is the best hope to restore balance to public education in the country. The next few years will tell us whether this “suggestion” is so