Total Number Of Crossings Research Articles

Green Vehicles’ Responses to an Expiring Congestion Toll Exemption: Findings from a Natural Experiment in Stockholm, Sweden

Stockholm established time-varying congestion pricing in 2007, and adopted a toll exemption as a temporary incentive for green vehicles (GVs) that ended in 2012. We examine the behavioral effects of phasing out the exemption by studying the change in cordon crossing events for GV morning commuters between May 2012 and May 2013, with a random sample of conventional vehicles (CVs) as control. The results suggest i) a significant drop in the total number of crossings; ii) a slight shift towards later journeys in the morning; and iii) a reduction in the ratio of peak-toll period crossings to other ones.

Space-efficient algorithms for reachability in directed geometric graphs

The problem of graph Reachability is to decide whether there is a path from one vertex to another in a given graph. In this paper, we study the Reachability problem on three distinct graph families - intersection graphs of Jordan regions, unit contact disk graphs (penny graphs), and chordal graphs. For each of these graph families, we present space-efficient algorithms for the Reachability problem.For intersection graphs of Jordan regions, we show how to obtain a “good” vertex separator in a space-efficient manner and use it to solve the Reachability in polynomial time and O(m1/2log⁡n) space, where n is the number of Jordan regions, and m is the total number of crossings among the regions. We use a similar approach for chordal graphs and obtain a polynomial time and O(m1/2log⁡n) space algorithm, where n and m are the number of vertices and edges, respectively. However, for unit contact disk graphs (penny graphs), we use a more involved technique and obtain a better algorithm. We show that for every ϵ>0, there exists a polynomial time algorithm that can solve Reachability in an n vertex directed penny graph, using O(n1/4+ϵ) space. We note that the method used to solve penny graphs does not extend naturally to the class of geometric intersection graphs that include arbitrary size cliques.

Testing gap k-planarity is NP-complete

For all k≥1, we show that deciding whether a graph is k-planar is NP-complete, extending the well-known fact that deciding 1-planarity is NP-complete. Furthermore, we show that the gap version of this decision problem is NP-complete. In particular, given a graph with local crossing number either at most k≥1 or at least 2k, we show that it is NP-complete to decide whether the local crossing number is at most k or at least 2k. This algorithmic lower bound proves the non-existence of a (2−ϵ)-approximation algorithm for any fixed k≥1. In addition, we analyze the sometimes competing relationship between the local crossing number (maximum number of crossings per edge) and crossing number (total number of crossings) of a drawing. We present results regarding the non-existence of drawings that simultaneously approximately minimize both the local crossing number and crossing number of a graph.

Paeoniflorin ameliorates depressive-like behavior in prenatally stressed offspring by restoring the HPA axis- and glucocorticoid receptor- associated dysfunction

BackgroundPrenatal stress (PS) can increase the risk of nervous, endocrine and metabolic diseases and induce depression in offspring. Paeoniflorin (PA) is an amorphous glucoside isolated from the aqueous extract of roots of the peony plant (Paeonia lactiflora Pall.) and exerts various pharmacological effects in the nervous system. MethodsMale prenatally stressed offspring were used to investigate the antidepression-like effects and possible mechanism of PA. We measured animal behavior, HPA axis, Nissil staining, and Ng expression. Additionally, we assessed the modulation of hippocampal glucocorticoid receptors (GR) nuclear translocation and SNARE complex expression by western blotting. ResultsThe results showed that administration of PA (15, 30, and 60 mg/kg/day, i.g.) for 28 days markedly increased sucrose intake and decreased the immobility time and the total number of crossings, center crossings, rearing, and grooming in male PS offspring. Moreover, PA significantly reduced the serum corticosterone (CORT), adrenocorticotropin (ACTH), corticotropin-releasing hormone (CRH) and hippocampal glutamate (Glu) levels in male PS offspring, which were stimulated by an increase of GR nuclear translocation. Furthermore, PA markedly increased neurogranin (Ng) protein expression in the hippocampus CA3 region in offspring. PA also markedly decreased hippocampal Glu by inhibiting SNAP25, VAMP2, Syntaxin1a and related protein expression; SNARE complex formation; and EAAT2/3, NR1, NR2A, and FKBP5 protein expression. ConclusionsTaken together, the results of this study show that PA has antidepression-like effects in male PS offspring, partially due to the HPA axis, GR dysfunction and Glu transport system.

Ferulic Acid Improves Depressive-Like Behavior in Prenatally-Stressed Offspring Rats via Anti-Inflammatory Activity and HPA Axis.

Prenatal stress (PS) can increase the risk of nervous, endocrine and metabolic diseases, and immune dysfunction. Ferulic acid (FA) is a dietary phenolic acid that has pharmacological properties, including potent anti-inflammatory action. We used male, prenatally-stressed offspring rats to investigate the anti-depressive-like effects and possible anti-inflammatory mechanism of FA. We determined the animal behaviors, and the mRNA expression and concentration of inflammatory cytokines, and HPA axis. In addition, we assessed the modulation of hippocampal nuclear factor-κB (NF-κB) activation, neuronal nitric oxide synthase (nNOS) and glucocorticoid receptors (GR) expression via western blotting and immunohistochemistry. Administration of FA (12.5, 25, and 50 mg/kg/day, i.g.) for 28 days markedly increased sucrose intake, and decreased immobility time and total number of crossings, center crossings, rearing, and grooming in the male PS offspring. FA significantly reduced IL-6, IL-1β, and TNF-α concentration and increased IL-10 concentration in male, prenatally-stressed offspring, stimulated by the NF-κB pathway. In addition, FA inhibited interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α), and increased interleukin-10 (IL-10) mRNA and protein expression. Furthermore, FA markedly decreased the serum adrenocorticotropin (ACTH) and corticosterone concentration by the increase of GR protein expression. Taken together, this study revealed that FA has anti-depressive-like effects in male, prenatally-stressed offspring, partially due to its anti-inflammatory activity and hypothalamic-pituitary-adrenal (HPA) axis.

Randomized incremental construction for the Hausdorff Voronoi diagram revisited and extended

This paper applies the randomized incremental construction (RIC) framework to computing the Hausdorff Voronoi diagram of a family of k clusters of points in the plane. The total number of points is n. The diagram is a generalization of Voronoi diagrams based on the Hausdorff distance function. The combinatorial complexity of the Hausdorff Voronoi diagram is O(n+m), where m is the total number of crossings between pairs of clusters. For non-crossing clusters (m=0), our algorithm works in expected O(n log n + k log n log k) time and deterministic O(n) space. For arbitrary clusters (m=O(n^2)), the algorithm runs in expected O((m+n log k) log n) time and O(m +n log k) space. When clusters cross, bisectors are disconnected curves resulting in disconnected Voronoi regions that challenge the incremental construction. This paper applies the RIC paradigm to a Voronoi diagram with disconnected regions and disconnected bisectors, for the first time.

Behavioral and mutagenic biomarkers in tadpoles exposed to different abamectin concentrations.

It is known that pesticides such as abamectin (ABA) present cytotoxic effects on target organisms; however, the effects from ABA on non-target organisms such as amphibians are poorly understood. The aim of the current study is to investigate whether the exposure of Lithobates catesbeianus tadpoles to different abamectin concentrations [12.5, 25, and 50% of the median lethal concentration (LC50)] leads to behavioral and morphological changes and/or generates possible cytotoxic effects. The aggregation test showed that tadpoles exposed to the highest ABA concentrations did not respond to the stimulus from non-familial and unrelated co-specific species. On the other hand, there was no difference in the total number of crossings in the central line of the herein adopted apparatus between groups; it suggests that ABA did not affect animal locomotion in the aforementioned test, although changes in the normal swimming pattern of tadpoles exposed to the pesticide were recorded in the swimming activity test. In addition, the herein exposed animals did not respond to the predatory stimulus in the antipredator response test; this result suggests defensive response deficit caused by the pesticide. With respect to their oral morphology, tadpoles exposed to ABA presented the lowest scores for mandibular pigmentation and structures, as well as for dentition condition. Finally, it was possible seeing that the exposure to ABA, even at the lowest concentration (12.5% of the LC50), resulted in nuclear changes in the erythrocytes of the animals; these changes became evident in the increased number of micronuclei and in other nuclear abnormalities. Thus, besides confirming the cytotoxic potential of ABA in amphibians, the current study corroborates the hypothesis that the exposure to the herein investigated pesticide leads to behavioral and morphological changes in tadpoles, fact that may negatively reflect on the survival, as well as on natural populations of these individuals.

On Metro-Line Crossing Minimization

We consider the problem of drawing a set of simple paths along the edges of an embedded underlying graph G = (V;E) so that the total number of crossings among pairs of paths is minimized. This problem arises when drawing metro maps, where the embedding of G depicts the structure of the underlying network, the nodes of G correspond to train stations, an edge connecting two nodes implies that there exists a railway track connecting them, whereas the paths illustrate the metro lines connecting terminal stations. We call this the metro-line crossing minimization problem (MLCM). We examine several variations of the problem for which we develop algorithms that yield optimal solutions.

An efficient parallel algorithm for the minimum crossing number problem

An efficient parallel algorithm for the minimum crossing number problem is presented. The algorithm, which is designed to embed the edges of a graph such that the total number of crossings is minimized, is based on an improved Hopfield neural network in which the internal dynamics is modified to permit temporary increases of the energy function so that the network can escape from local minima. The proposed algorithm is tested on several complete graphs and the simulation results show that the proposed algorithm provides a high probability of finding optimal solutions.

Gender-related response in open-field activity following developmental nicotine exposure in rats

Smoking during pregnancy may lead to low birthweight and behavioral alterations in the offspring. In this study, the effects of developmental nicotine exposure on the somatic growth of the offspring and the behavioral performance in the open-field test were examined. Sprague–Dawley female rats were implanted with nicotine (35 mg for 21-day time release; NIC 35) or placebo pellets on gestational day (GD) 8 (postblastocyst implantation). A normal control group with no pellet implant was also included. There was a significantly higher maternal weight gain in the placebo group possibly due to a larger litter size. However, there were no significant differences in body weights among all three treatment groups for male and female offspring. The amount of activity, measured by the total number of crossings in the open-field test, indicated a gender difference in baseline level and pattern of ambulatory activity, with less activity (lower number of crossings) in male offspring and an increase in the activity of the female offspring as a function of testing day. The increase in the ambulatory activity of the female offspring was observed in the placebo and normal, but not the NIC 35 group suggesting that developmental nicotine exposure interferes with open-field activity, and this behavioral alteration is gender related.

Agmatine induces anxiolysis in the elevated plus maze task in adult rats

Agmatine is an endogenous released polyamine recently proposed to be a putative neurotransmitter, however its physiological role is still to be determined. We investigated the hypothesis that agmatine, systemically administered to adult Wistar rats, might exert anxiolytic-like behavior in the elevated plus maze (EPM) and the open field. Agmatine (1, 10, 20, 40 and 100 mg/kg) and saline were administered i.p. 30 min before the EPM and the open field. Administration of agmatine (20 and 40 mg/kg) increased the time spent in the open arms of the EPM, as compared to the saline group, with no effect on locomotion activity in the open field. However, 100 mg/kg of agmatine significantly reduced the number of entries into enclosed arms of the EPM and the total number of crossings in the open field. We suggest that agmatine, in doses of 20 and 40 mg/kg, causes a mild anxiolytic-like behavior and discuss the possibility that this first reported effect could be caused either by the inhibition of nitric oxide synthase, the blockage of NMDA receptors or by the activation of alpha-2-adrenoceptors.

Study on ‘‘regularity’’ of barrier recrossing motion

A method to scrutinize ‘‘regularity’’ of barrier recrossing dynamics of chemical reactions in the vicinity of the transition state is developed by using Lie canonical perturbation theory (LCPT). As an example, the recrossing dynamics of a four-degrees of freedom Hamiltonian regarded as a model of proton transfer reaction of malonaldehyde is investigated. It is shown that the second order LCPT is essential to describe frequent saddle recrossings whose total number of crossings is greater than three, and reproduces the time-dependent transmission coefficient. It is found that the local recrossing dynamics can be regarded as quasiperiodic and a well-defined reaction coordinate along which no barrier recrossings occur, can be extracted in the phase space by using the second order LCPT Hamiltonian. We also formulate a new transition state theory which allows us to estimate the reaction rate constant taking account of the barrier recrossing effect if the recrossings are near-integrable in the short time but long enough to determine the final state of the recrossing dynamics.

Impression materials: effect of hydrophilicity and viscosity on ability to displace water from dentin surfaces.

The water-displacing ability of hydrophilic and hydrophobic impression materials was determined and related to the hydrophilicity and viscosity of the materials. The water-displacing ability of the materials was determined on a network of grooves in a dentin surface covered by a drop of water. After setting of the material, the number of crossings reproduced in the impression was calculated in percent of the total number of crossings. The hydrophilicity was assessed by measuring the contact angle between water and impression material. To determine viscosity, a rotoviscosimeter was used. Impression materials with contact angles less than 70 degrees showed a significant negative correlation between water-displacing ability and contact angle, i.e. the reproducing ability decreased with decreasing hydrophilicity of the materials. Impression materials with contact angles above 70 degrees showed a significant positive correlation between water-displacing ability and viscosity, i.e. the water-displacing ability improved with increasing viscosity.