On the Spatial Evolution of Traffic State Transitions: Empirical Observations and General Features

2019 ◽  
Vol 2673 (12) ◽  
pp. 606-618
Author(s):  
Paulina Reina ◽  
George Saman ◽  
Soyoung Ahn
Keyword(s):  
Transition Zone ◽  
Considerable Effect ◽  
State Transitions ◽  
Spatial Evolution ◽  
Transition Rates ◽  
Traffic State ◽  
Average Transition

Features of transitions between stationary traffic states for both congestion onset and dissipation were evaluated through empirical observations at two freeway sites. Results reveal that transition durations vary significantly between sites and that they can be rather long, with observed average transition durations of 42–45 min in one site. It was also observed that transition durations remain relatively constant within a queue, while transition rates vary as the transition zone travels upstream of the bottleneck. In addition, results also suggest that complex site geometry, particularly the presence of multiple lane reductions, has an effect on the spatial evolution of transition rates, while single merging and diverging maneuvers do not seem to affect the mechanism of transitions. Finally, it was observed that the presence of non-stationary traffic periods could have a considerable effect on the estimation of key traffic variables in locations where long transition durations are observed.

Transcompp: understanding phenotypic plasticity by estimating Markov transition rates for cell state transitions

2020 ◽  
Vol 36 (9) ◽  
pp. 2813-2820
Author(s):  
N Suhas Jagannathan ◽  
Mario O Ihsan ◽  
Xiao Xuan Kin ◽  
Roy E Welsch ◽  
Marie-Véronique Clément ◽  
...  
Keyword(s):  
Cell Culture ◽  
Phenotypic Plasticity ◽  
Cell Population ◽  
Single Cells ◽  
Supplementary Information ◽  
State Transitions ◽  
Cell Phenotype ◽  
Markov Modeling ◽  
Transition Rates ◽  
Cell State

Abstract Motivation Gradual population-level changes in tissues can be driven by stochastic plasticity, meaning rare stochastic transitions of single-cell phenotype. Quantifying the rates of these stochastic transitions requires time-intensive experiments, and analysis is generally confounded by simultaneous bidirectional transitions and asymmetric proliferation kinetics. To quantify cellular plasticity, we developed Transcompp (Transition Rate ANalysis of Single Cells to Observe and Measure Phenotypic Plasticity), a Markov modeling algorithm that uses optimization and resampling to compute best-fit rates and statistical intervals for stochastic cell-state transitions. Results We applied Transcompp to time-series datasets in which purified subpopulations of stem-like or non-stem cancer cells were exposed to various cell culture environments, and allowed to re-equilibrate spontaneously over time. Results revealed that commonly used cell culture reagents hydrocortisone and cholera toxin shifted the cell population equilibrium toward stem-like or non-stem states, respectively, in the basal-like breast cancer cell line MCF10CA1a. In addition, applying Transcompp to patient-derived cells showed that transition rates computed from short-term experiments could predict long-term trajectories and equilibrium convergence of the cultured cell population. Availability and implementation Freely available for download at http://github.com/nsuhasj/Transcompp. Supplementary information Supplementary data are available at Bioinformatics online.

scholarly journals Mathematical modelling of activation-induced heterogeneity reveals cell state transitions underpinning macrophage responses to LPS

2021 ◽  
Author(s):  
Shoumit Dey ◽  
Dave Boucher ◽  
Jonathan William Pitchford ◽  
Dimitris Lagos
Keyword(s):  
Mathematical Modelling ◽  
Community Dynamics ◽  
Critical Role ◽  
State Model ◽  
Cell Protein ◽  
State Transitions ◽  
Raw 264.7 ◽  
Transition Rates ◽  
Cellular Models ◽  
Lps Challenge

Despite extensive work on macrophage heterogeneity, the mechanisms driving activation induced heterogeneity (AIH) in macrophages remain poorly understood. Here, we use two in vitro cellular models of LPS-induced tolerance (bone marrow-derived macrophages or BMDMs and RAW 264.7 cells), single-cell protein measurements, and mathematical modelling to explore how AIH underpins primary and secondary responses to LPS. We measure expression of TNF, IL-6, pro-IL-1β, and NOS2 and demonstrate that macrophage community AIH is dependent on LPS dose. We show that altered AIH kinetics in macrophages responding to a second LPS challenge underpin hypo-responsiveness to LPS. These empirical data can be explained by a mathematical 3-state model including negative, positive, and non-responsive states (NRS), but they are also compatible with a 4-state model that includes distinct reversibly NRS and non-responsive permanently states (NRPS). Our mathematical model, termed NoRM (Non-Responsive Macrophage) model identifies similarities and differences between BMDM and RAW 264.7 cell responses. In both cell types, transition rates between states in the NoRM model are distinct for each of the tested proteins and, crucially, macrophage hypo-responsiveness is underpinned by changes in transition rates to and from NRS. Overall, our findings provide support for a critical role for phenotypically negative macrophage populations as an active component of AIH and primary and secondary responses to LPS. This reveals unappreciated aspects of cellular ecology and community dynamics associated with LPS-driven training of macrophages.

Abstract 238: In-Hospital Cardiac Arrest: The Dynamic Clinical Course During Advanced Cardiac Life Support

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_2) ◽  
Author(s):  
Eirik Skogvoll ◽  
David G Buckler ◽  
Trond Nordseth ◽  
Maria Brønstad ◽  
Trygve Eftestøl ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Life Support ◽  
Clinical Course ◽  
Pulseless Electrical Activity ◽  
Advanced Cardiac Life Support ◽  
Clinical State ◽  
State Transitions ◽  
Transition Rates ◽  
Chest Compressions ◽  
Hospital Cardiac Arrest

Background: Sudden cardiac arrest may present with one of three clinical states (rhythms): Ventricular fibrillation/tachycardia (VF/VT), Pulseless Electrical Activity (PEA), or Asystole (ASY). During Advanced Cardiac Life Support (ACLS), the patient may also transition between the other states or reach temporary ROSC (defined as an organized electrical rhythm without chest compressions >= 1 min). Finally, either sustained ROSC or death will ensue. The aim of study was to investigate and quantify the dynamic characteristics of this process and compare with previous studies. Methods: As part of a CPR quality assessment initiative, we prospectively registered the development of clinical states using defibrillators that records the ECG as well as ongoing chest compressions. These recordings were analyzed in a multi-state statistical framework. Instantaneous transition rates were obtained by smoothing the Nelson-Aalen estimator of cumulative intensities. Results: We analyzed 201 episodes in 168 patients between 2008 and 2009 at the Hospital of the University of Pennsylvania (51% women; median age 60, IQR 49-73 years). Most episodes (62%) took place in the Medical ICU, and represented multiple etiologies. PEA was the most frequent presenting rhythm (69%); VF/VT and ASY contributed with 15 % each. In the 191 episodes with complete information about the clinical course, the transition rate from PEA to ROSC was 0.11 episodes/min (approximately 11%), the rate of PEA recurring from temporary ROSC was 0.12/min. These transition rates are both about 40 % higher than observed earlier. The prevalence of sustained ROSC was 0.6 (60%) at about 25 min (figure: 0 to 45 min of CPR). Conclusion: We provide quantitative overview of the dynamic process of clinical state transitions during in-hospital cardiac arrest in adults. Compared to earlier studies from American and Norwegian Hospitals, we found higher transition rates between PEA to ROSC, and a high prevalence of sustained ROSC.

Space and Time Distribution of Hard X-Ray Emission in a Loop at the Beginning of a Flare

1994 ◽  
Vol 144 ◽  
pp. 275-277
Author(s):  
M. Karlický ◽  
J. C. Hénoux
Keyword(s):  
Time Distribution ◽  
Electron Bombardment ◽  
Spatial Evolution ◽  
Superthermal Electrons ◽  
Flare Loop ◽  
X Ray ◽  
Superthermal Electron ◽  
Flare Loops ◽  
Chromospheric Evaporation ◽  
Temporal And Spatial

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

Hysteresis in spectral state transitions – a challenge for theoretical modeling

2005 ◽  
Vol 432 (1) ◽  
pp. 181-187 ◽  
Author(s):  
E. Meyer-Hofmeister ◽  
B. F. Liu ◽  
F. Meyer
Keyword(s):  
Theoretical Modeling ◽  
State Transitions ◽  
Spectral State

Theoretical modeling of the regular olivine intergrowths in the mimetic paramorphosis after ringwoodite and wadsleyite

2018 ◽  
pp. 3-12
Author(s):  
B. B. Shkursky
Keyword(s):  
Transition Zone ◽  
Theoretical Modeling ◽  
Mantle Transition Zone ◽  
Misorientation Angles

Theoretical modeling of regular olivine grains misorientations in mimetic paramorphoses after ringwoodite and wadsleyite, the formation of which during the ascension of matter from the Mantle Transition Zone is expected, has been carried out. The coordinates of the misorientation axes and the misorientation angles, characterizing 10 operations of alignment in the pair intergrowths of olivine grains, eight of which are twins, are calculated. Possible conditions for the formation of mimetic paramorphoses predicted here, and the chances of their persistence are discussed. The calculated orientations are compared with the known twinning laws of olivine.

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