Search results for "traffic"
showing 10 items of 598 documents
Dynamics and Thermodynamics of Traffic Flow
2009
Application of thermodynamics to traffic flow is discussed. On a microscopic level, traffic flow is described by Bando’s optimal velocity model in terms of accelerating and decelerating forces. It allows us to introduce kinetic, potential, as well as a total energy, which is the internal energy of the car system in view of thermodynamics. The total energy is however not conserved, although it has a certain value in any of the two possible stationary states corresponding either to a fixed point or to a limit cycle solution in the space of headways and velocities.
Probabilistic description of traffic flow
2005
Abstract A stochastic description of traffic flow, called probabilistic traffic flow theory, is developed. The general master equation is applied to relatively simple models to describe the formation and dissolution of traffic congestions. Our approach is mainly based on spatially homogeneous systems like periodically closed circular rings without on- and off-ramps. We consider a stochastic one-step process of growth or shrinkage of a car cluster (jam). As generalization we discuss the coexistence of several car clusters of different sizes. The basic problem is to find a physically motivated ansatz for the transition rates of the attachment and detachment of individual cars to a car cluster…
Application of thermodynamics to driven systems
2007
Application of thermodynamics to driven systems is discussed. As particular examples, simple traffic flow models are considered. On a microscopic level, traffic flow is described by Bando's optimal velocity model in terms of accelerating and decelerating forces. It allows to introduce kinetic, potential, as well as total energy, which is the internal energy of the car system in view of thermodynamics. The latter is not conserved, although it has certain value in any of two possible stationary states corresponding either to fixed point or to limit cycle in the space of headways and velocities. On a mesoscopic level of description, the size n of car cluster is considered as a stochastic varia…
Probabilistic description of traffic breakdowns
2001
We analyze the characteristic features of traffic breakdown. To describe this phenomenon we apply to the probabilistic model regarding the jam emergence as the formation of a large car cluster on highway. In these terms the breakdown occurs through the formation of a certain critical nucleus in the metastable vehicle flow, which enables us to confine ourselves to one cluster model. We assume that, first, the growth of the car cluster is governed by attachment of cars to the cluster whose rate is mainly determined by the mean headway distance between the car in the vehicle flow and, may be, also by the headway distance in the cluster. Second, the cluster dissolution is determined by the car …
Metastability of Traffic Flow in Zero-Range Model
2007
The development of traffic jams in vehicular flow is an everyday example of the occurence of phase separation in low-dimensional driven systems, a topic which has attracted much recent interest [1–4]. In [5] the existence of phase separation is related to the size-dependence of domain currents and a quantitative criterion is obtained by considering the zero-range process (ZRP) as a generic model for domain dynamics. We use zero-range picture to study the phase separation in traffic flow in the spirit of the probabilistic (master equation) description of transportation [6]. Significantly, we find [7] that prior to condensation studied in previous works [8, 9] the system can exist in a homoge…
Stochastic description of traffic breakdown
2003
We present a comparison of nucleation in an isothermal-isochoric container with traffic congestion on a one-lane freeway. The analysis is based, in both cases, on the probabilistic description by stochastic master equations. Further we analyze the characteristic features of traffic breakdowns. To describe this phenomenon we apply the stochastic model regarding the jam emergence to the formation of a large car cluster on the highway.
The depletion of nuclear glutathione impairs cell proliferation in 3t3 fibroblasts.
2009
BACKGROUND:Glutathione is considered essential for survival in mammalian cells and yeast but not in prokaryotic cells. The presence of a nuclear pool of glutathione has been demonstrated but its role in cellular proliferation and differentiation is still a matter of debate. PRINCIPAL FINDINGS:We have studied proliferation of 3T3 fibroblasts for a period of 5 days. Cells were treated with two well known depleting agents, diethyl maleate (DEM) and buthionine sulfoximine (BSO), and the cellular and nuclear glutathione levels were assessed by analytical and confocal microscopic techniques, respectively. Both agents decreased total cellular glutathione although depletion by BSO was more sustaine…
Between Local and Global: the ‘Ndrangheta’s Drug Trafficking Route
2017
AbstractAccording to the last United Nations Office on Drugs and Crime report (2016), 247 million people aged between 15 and 64 years used drugs at least once in the past year, with cocaine being the best-selling of the goods from the ‘Ndrangheta. In this case, the drugs trade is 60% of the systemic gain due to illicit trafficking that allowed the spreading of the Calabrian criminal organization across five continents. Nevertheless, this sometimes little-known apparently harmless organization, which comes from the Aspromonte heartland in Calabria, was included by the United States in the blacklist of the 75 most dangerous drug-trafficking organizations only in 2008. Therefore, this investig…
Motherhood of Nigerian and Romanian Women in Sexual Exploitation
2020
Motherhood in human trafficking can cause a transition from an invisible individual, marginalised by their administrative and social status, into a ‘recognised citizen’ (Brouckaert and Longman 2018). This is to do with ‘the constitute maternal act’ (Ruddick 1995), in which the role of care is assumed regarding the child necessities, bringing with it help for the mother in order to fulfil necessary services (Brouckaert and Longman 2018). Therefore, motherhood can be perceived, especially by the trafficker as an added vulnerability factor, due to the responsibility that the victim feels in protecting the baby. However, on the other hand, the responsibility in protecting another life can also …
The EU and global imbalances
2015
The EU’s Role in Fighting Global Imbalances looks at the role of the European Union in addressing some of the greatest challenges of our time: poverty, protectionism, climate change, and human trafficking. Contributions from ten leading scholars in the fields of economics, law, and political science provide in-depth analyses of three key dimensions of EU foreign policy, namely: the internal challenges facing the EU, as its 28 member countries struggle to coordinate their actions; the external challenges facing the EU on the global arena, in areas where global imbalances are particularly pervasive, and where measures taken by the Union can have an important impact; and the EU´s performance o…