Collision Site Research Articles

Relationship between the atrial-activation pattern around the triangle of Koch and successful ablation sites in slow-fast atrioventricular nodal reentrant tachycardia.

The precise details of atrial activation around the triangle of Koch (ToK) remain unknown. We evaluated the relationship between the atrial-activation pattern around the ToK and success sites for slow-pathway (SP) modification ablation in slow-fast atrioventricular reentrant tachycardia (AVNRT). Thirty patients with slow-fast AVNRT who underwent successful ablation were enrolled. Atrial activation around the ToK during sinus rhythm was investigated using ultra-high-density mapping pre-ablation. The relationships among features of atrial-activation pattern and success sites were examined. Of 30 patients (22 cryoablation; 8 radiofrequency ablation), 26 patients had a collision site of two wavefronts of delayed atrial activation within ToK, indicating a success site. The activation-search function of Lumipoint software, which highlights only atrial activation with a spatiotemporal consistency, showed non-highlighted area on the tricuspid-annulus side of ToK. In 23 of the patients, a spiky potential was recorded at that collision site outside the Lumipoint-highlighted area. Fifteen cryoablation patients with a success site coincident with a collision site outside the Lumipoint-highlighted area had significantly more frequent disappearances of SP after initial cryoablation (46.7% vs. 0%, p = .029), fewer cryoablations (3.7 ± 1.8 vs. 5.3 ± 1.3, p = .045), and shorter procedure times (170 ± 57 vs. 228 ± 91 min, p = .082) compared to the seven cryoablation patients without such sites. Four patients had transient AV block by ablation inside the Lumipoint-highlighted area with fractionated signals, but no patient developed permanent AV block or recurrence post-procedure (median follow-up: 375 days). SP modification ablation at the collision site of atrial activation of the tricuspid-annulus side along with a spiky potential could provide a better outcome.

Septins provide microenvironment sensing and cortical actomyosin partitioning in motile amoeboid T lymphocytes.

The all-terrain motility of lymphocytes in tissues and tissue-like gels is best described as amoeboid motility. For amoeboid motility, lymphocytes do not require specific biochemical or structural modifications to the surrounding extracellular matrix. Instead, they rely on changing shape and steric interactions with the microenvironment. However, the exact mechanism of amoeboid motility remains elusive. Here, we report that septins participate in amoeboid motility of T cells, enabling the formation of F-actin and α-actinin-rich cortical rings at the sites of cell cortex-indenting collisions with the extracellular matrix. Cortical rings compartmentalize cells into chains of spherical segments that are spatially conformed to the available lumens, forming transient "hourglass"-shaped steric locks onto the surrounding collagen fibers. The steric lock facilitates pressure-driven peristaltic propulsion of cytosolic content by individually contracting cell segments. Our results suggest that septins provide microenvironment-guided partitioning of actomyosin contractility and steric pivots required for amoeboid motility of T cells in tissue-like microenvironments.

Mechanism of ionic dissociation of HCl in the smallest water clusters.

The dissociation of strong acids into water is a fundamental process in chemistry and biology. Determining the minimum number of water molecules that can result in an ionic dissociation of hydrochloric acid (HCl → H+ + Cl-) remains a challenging subject. In this study, the reactions of H2O with HCl(H2O)n-1 (HCl-H2O cluster), i.e., HCl(H2O)n-1 + H2O (n = 3-7), were investigated by using the direct ab initio molecular dynamics (AIMD) method. Direct AIMD calculations were performed to set the collision energy of H2O to zero for all trajectories. For n = 3, no reaction occurred. In contrast, HCl dissociated to H+ + Cl- at n = 4, forming a contact ion pair (cIP) and solvent-separated ion pair (ssIP) as products. The reactions were expressed as HCl(H2O)3 + H2O → H3O+(H2O)2Cl- (ssIP), and HCl(H2O)3 + H2O → H3O+(Cl-)(H2O)2 (cIP). The ion pair (IP) products were dependent on the collision site of H2O relative to HCl(H2O)3. For n = 5-7, both IPs were formed through the reaction between H2O and HCl(H2O)n-1 (n = 5-7). The reaction between HCl and (H2O)4 (HCl + (H2O)4 → HCl(H2O)4) was non-reactive in IP formation. The reaction mechanism was discussed based on the theoretical results.

Hole behavior captured by analysis of instantaneous amplitude and phase of sarcosynced oscillations reveals wave characteristics of sarcomeric oscillations

In this study, we performed signal analysis based on instantaneous amplitude and phase of sarcomeric oscillations, which are generated by skeletal muscle under constant calcium concentration conditions and in which sarcomeres repeatedly contract and relax autonomously. In addition to the changes in sarcomere length that have been attracting attention, we named the Z-line oscillations that partition sarcomeres sarcosynced oscillations, and analyzed their instantaneous amplitude and phase. As a result, the behavior of pairs of sarcosynced oscillations and sarcomeric oscillations, which are produced when propagating waves propagate in one direction or collide, was clearly visualized. By focusing on the behavior of the hole, which is a dip in the instantaneous amplitude accompanied by a sudden jump in the instantaneous phase in sarcosynced oscillations, we were able to discern the wave characteristics. Transient disruption occurred in the propagating waves even when they traveled in one direction. Its properties were captured by the sarcomeric defect hole (SD hole), a dip in the instantaneous amplitude accompanied by a jump in the instantaneous phase in sarcosynced oscillations. When propagating waves collide, the collision site, its persistence, movement, and disappearance process are captured as sarcomeric collision holes (SC holes) of sarcosynced oscillations. These holes are important indicators for understanding the oscillation properties of sarcomeres. In conclusion, although sarcosynced oscillations and sarcomeric oscillations are closely related, they exhibit different oscillations, and the study of the SD holes and SC holes caused by them will contribute to a detailed understanding of the muscle characteristics of sarcomeres. This finding has important implications for improving our understanding of the efficiency of muscle function and its regulatory mechanisms.

3D simulation of interosseous interference in sagittal split ramus osteotomy for mandibular asymmetry

BackgroundThe purpose of this study was to evaluate the pattern of predicted interosseous interference and to determine the influencing factor to volume of bony interference using a computer-assisted simulation system. This retrospective study recruited 116 patients with mandibular prognathism who had undergone sagittal split ramus osteotomy (SSRO) with or without maxillary osteotomy. The patients were divided into 3 groups according to the amount of menton (Me) deviation: less than 2 mm (Group 1), 2–4 mm (Group 2), and more than 4 mm (Group 3). Changes in the distal segments following BSSRO and the volume of the interosseous interference between the proximal and distal segments were simulated after matching preoperative occlusion and postoperative expected occlusion with the cone-beam computed tomography data. Ramal inclinations and other skeletal measurements were analyzed before surgery, immediately after surgery, and at least 6 months after surgery.ResultsThe anticipated interosseous interference was more frequently noted on the contralateral side of chin deviation (long side) than the deviated site (short side) in Groups 2 and 3. More interference volume was predicted at the long side (186 ± 343.9 mm3) rather than the short side (54.4 ± 124.4 mm3) in Group 3 (p = 0.033). The bilateral difference in the volume of the interosseous interference of the osteotomized mandible was significantly correlated with the Me deviation (r =  − 0.257, p = 0.009) and bilateral ramal inclination (r = 0.361, p < 0.001). The predictor variable that affected the volume of the osseous interference at each side was the amount of Me deviation (p = 0.010).ConclusionBy using the 3D simulation system, the potential site of bony collision could be visualized and successfully reduced intraoperatively. Since the osseous interference can be existed on any side, unilaterally or bilaterally, 3D surgical simulation is necessary before surgery to predict the osseous interference and improve the ramal inclination.

A Bright First Day for Tidal Disruption Events

Stream–stream collision may be an important prepeak energy dissipation mechanism in tidal disruption events (TDEs). We perform local three-dimensional radiation hydrodynamic simulations in a wedge geometry including the gravity to study stream self-crossing with an emphasis on resolving the collision and following the subsequent outflow. We find that the collision can contribute to prepeak optical emissions by converting ≳5% of the stream kinetic energy to radiation, yielding prompt emission of ∼1042−44 erg s−1. The radiative efficiency is sensitive to stream mass fallback rates and strongly depends on the downstream gas optical depth. Even for a sub-Eddington (10%) mass fallback rate, the strong radiation pressure produced in the collision can form a local super-Eddington region near the collision site, where a fast, aspherical outflow is launched. A higher mass fallback rate usually leads to more optically thick outflow and lower net radiative efficiency. For , the estimated photosphere size of the outflow can expand by 1–2 orders of magnitude, reaching ∼1014 cm. The average gas temperature at this photospheric surface is a few × 104 K, roughly consistent with inferred prepeak photosphere properties for some optical TDEs. We find that the dynamics is sensitive to the collision angle and radius, but the radiative efficiency or outflow properties show more complex dependency than is often assumed in ballistic models.

Early Mesoproterozoic (1.72–1.68 Ga) convergence between Bastar and Eastern Dharwar cratons along the Bhopalpatnam orogen, southcentral India and implication for paleogeography of supercontinent Columbia

Temporal constraints on orogen initiation and duration are critical for the Paleoproterozoic reconstruction of cratons presently constituting India. Recent late Paleoproterozoic paleomagnetic pole data indicate proximity of Eastern Dharwar, Bastar and Singhbhum cratons and in view of global Mesoproterozoic-aged final Columbia assembly, reconstruction sequence of Indic cratons is critical to assess whether they constituted Columbia. The initiation time and duration of the Bhopalpatnam orogen, developed between the Eastern Dharwar and Bastar cratons, range from earliest Mesoproterozoic to Neoarchean. Therefore, in order to constrain the earliest stages of cratonic convergence and crustal thickening, the time of peak metamorphism was established on tectonites, sampled from > 300 km along newly classified longitudinal domains representative of the entire Bhopalpatnam orogen, by precise combined garnet Lu-Hf and Sm-Nd chronology of amphibolite-and granulite-facies rocks. Interpreting the Lu-Hf and Sm-Nd isochron weighted mean ages, an orogenic duration of 38 ± 19 Myr is inferred between the high-pressure amphibolite-facies through to granulite-facies event at 1721 ± 14 Ma and a post-peak cooling to ≤ 650 °C at 1683 ± 6 Ma, being the Sm-Nd garnet weighted mean age. Archean two-stage depleted mantle model ages (at 1.7 Ga) of tectonites and rotated dyke swarm orientations support the reactivation and reworking of the Paleo- to Neoarchean Bastar craton marginal rocks in response to the early Mesoproterozoic orogeny. Based on the clockwise P-T path involving an early high-pressure amphibolite-facies stage (Pmax ≥ 12 kbar at ∼ 750 °C) followed by a granulite-facies stage (Tmax ≤ 850 °C at lower pressures), we interpret the orogen to represent deeply exhumed thrust slices of the reworked Bastar craton leading edge underthrusted beneath the Eastern Dharwar craton. As paleomagnetic data indicates proximity or contiguity of Bastar and Eastern Dharwar cratons by 1.79 Ga, the Bhopalapatnam orogen could represent site of early Mesoproterozoic cratonic collision or locus of post amalgamation reactivation due to convergence.

Hydrogeochemistry, Geothermometry, and Sourcing of High Dissolved Boron, Tungsten, and Chlorine Concentrations in the Trans-Himalayan Hotsprings of Ladakh, India

Boron (B) and Tungsten (W) are often found enriched in high-temperature geothermal waters associated with the development of subduction-related mafic to felsic arc magma. However, knowledge about the sourcing and transportation of these elements from such hydrothermal systems is sparse and ambiguous. Being the only active continental collision site in the world, the Trans-Himalaya offers a unique chance to study how continental collision sources the high boron and tungsten concentrations in geothermal fluids. This study investigated the distribution of trace elements, major cations, and anions in three physicochemically distinct hotspring sites in the Ladakh region. The results were integrated with the existing geochemical and isotopic data to address the research problem more effectively. This study exhibits that the extreme concentrations of boron, sodium, chlorine, potassium, and tungsten in the hotspring waters were primarily governed by magmatic fluid inputs. In addition, this study recorded the highest-ever chlorine and boron concentrations for the Trans-Himalayan hotspring waters. The highest-ever boron and chlorine concentrations in the hotspring waters probably represented an increase in magmatic activity in the deeper source zone.

In Atrial Fibrillation, Omnipolar Voltage Maps More Accurately Delineate Scar Than Bipolar Voltage Maps

BackgroundOptimal method for voltage assessment in AF remains unclear. ObjectivesThis study evaluated different methods for assessing atrial voltage and their accuracy in identifying pulmonary vein reconnection sites (PVRSs) in atrial fibrillation (AF). MethodsPatients with persistent AF undergoing ablation were included. De novo procedures: voltage assessment in AF with omnipolar voltage (OV) and bipolar voltage (BV) methodology and BV assessment in sinus rhythm (SR). Activation vector and fractionation maps were reviewed at voltage discrepancy sites on OV and BV maps in AF. AF voltage maps were compared with SR BV maps. Repeat ablation procedures: OV and BV maps in AF were compared to detect gaps in wide area circumferential ablation (WACA) lines that correlated with PVRS. ResultsForty patients were included: 20 de novo and 20 repeat procedures. De novo procedure: OV vs BV maps in AF; average voltage 0.55 ± 0.18 mV vs 0.38 ± 0.12 mV; P = 0.002, voltage difference of 0.20 ± 0.07 mV; P = 0.003 at coregistered points and proportion of left atrium (LA) area occupied by low-voltage zones (LVZs) was smaller on OV maps (42.4% ± 12.8% OV vs 66.7% ± 12.7% BV; P < 0.001). LVZs identified on BV maps and not on OV maps correlated frequently to wavefront collision and fractionation sites (94.7%). OV AF maps agreed better with BV SR maps (voltage difference at coregistered points 0.09 ± 0.03 mV; P = 0.24) unlike BV AF maps (0.17 ± 0.07 mV, P = 0.002). Repeat ablation procedure: OV was superior in identifying WACA line gaps that correlated with PVRS than BV maps (area under the curve = 0.89, P < 0.001). ConclusionsOV AF maps improve voltage assessment by overcoming the impact of wavefront collision and fractionation. OV AF maps correlate better with BV maps in SR and more accurately delineate gaps on WACA lines at PVRS.

(Re)ordering the Mediterranean: The evolution of security assistance as an international practice

ABSTRACT Security assistance – foreign actors training and equipping security forces in another country – has proliferated in the Mediterranean over the last decades. Now, more than a decade on from the Arab Uprisings, security assistance cannot be considered merely a tool to obtain strategic objectives, but is in itself a site of competition, collusion and potential collision. In this Introduction to the Special Issue, we develop a framework deploying reordering as a lens through which comparative and interdisciplinary explorations can develop comprehensive and critical views of the evolution of security assistance in the Mediterranean. We propose a theoretical framework centred on international practice and socio-material network theory, which brings different types of providers and recipients, as well as the discourse-material structures underpinning them, into a common frame. The framework conceptualizes security assistance as operating at vertical (between provider and recipient), and horizontal (between vertical blocks) levels. It can purposefully be analysed across three dimensions – knowledge, materiality and networks. In so doing, we may be able to observe how, despite the absence of formal institutions, norms or governing mechanisms, security assistance constitutes an international practice and contributes to the ordering, and continuous reordering, of the Mediterranean as a governable geospatial field of intervention.

Molecular dynamics of He encapsulation in the C20H20 cage at the threshold energy

The encapsulation of He inside C20H20 cage has been investigated in the framework of molecular dynamics for incident atom energy in a range close to the threshold value, corresponding to the projectile passing through the pentagonal carbon ring. The entrance of He atom into dodecahedrane is analyzed in terms of static and dynamic potential barriers. The details of helium capture inside the molecular box is revealed by using geometric and energetic parameters, being associated with the response of the atomic configuration near the collision site on the C20H20 cage. The energy transferred from the incident atom to deformation, vibrations, and recoil of the molecule target, was calculated as a function of the distance between the projectile and the collision site on C20H20 cage. The calculations show that the noble gas atom, encapsulated at the threshold of 315.62 Å/ps, oscillates across the void of the dodecahedrane with frequencies of 2.5, 22.5, and 25.0 THz, monitored for a time interval of 10 ps starting at helium penetration into C20H20. Molecular dynamics calculations are based on ab-initio Hartree-Fock method, considering an adiabatic process. This study reveals advantageous features of helium encapsulation in dodecahedrane molecules in designing super-molecular structures for advanced nano sensors in the field of THz detectors.

Interactions between the Jet and Disk Wind in Nearby Radio-intermediate Quasar III Zw 2

Disk winds and jets are ubiquitous in active galactic nuclei (AGN), and how these two components interact remains an open question. We study the radio properties of the radio-intermediate quasar III Zw 2. We detect two jet knots, J1 and J2, on parsec scales that move at a mildly apparent superluminal speed of 1.35c. Two γ-ray flares were detected in III Zw 2 in 2009–2010, corresponding to the primary radio flare in late 2009 and the secondary radio flare in early 2010. The primary 2009 flare was found to be associated with the ejection of J2. The secondary 2010 flare occurred at a distance of ∼0.3 pc from the central engine, probably resulting from the collision of the jet with the accretion disk wind. The variability characteristics of III Zw 2 (periodic radio flares, unstable periodicity, multiple quasiperiodic signals and the possible harmonic relations between them) can be explained by the global instabilities of the accretion disk. These instabilities originating from the outer part of the warped disk propagate inward and can lead to modulation of the accretion rate and consequent jet ejection. At the same time, the wobbling of the outer disk may also lead to oscillations of the boundary between the disk wind and the jet tunnel, resulting in changes in the jet–wind collision site. Object III Zw 2 is one of the few cases observed with jet–wind interactions, and the study in this paper is of general interest for gaining insight into the dynamic processes in the nuclear regions of AGN.

What are the ideal systolic and diastolic blood pressure which do not injure the intima of iliac and coronary arteries?

Abstract   For patients with coronary artery disease, hypertension (HTN) is a major risk factor. How could uncontrolled HTN start atherosclerosis? In our prior research, laminar flow in coronary arteries prevented the formation of plaques while turbulent flow injured the intima and triggered atherosclerosis. In this present study our question was: Which blood pressure (BP) level is optimal in not producing turbulence and so not injuring the intima? Methods At first, a systolic BP&amp;lt;120mmHg and diastolic BP&amp;lt;75mmHg) were arbitrarily set as controlled (group A) while a BP of &amp;gt;160/105mmHg as uncontrolled (group B). All patients underwent a dynamic coronary angiogram recorded at 15 images/second or 0.06 seconds per image. The first image was of the index artery completely filled with contrast. In subsequent images the blood in white color moved in over a background of black contrast (Figure 1A). In 1B, 0.06 seconds later, the blood arrived at the mid segment (white arrow). In 1C, the flood moved forward, however there was darker contrast hanging at the mid segment, marking the location of collision from the retrograde against the antegrade flow (white arrow). The reason was that in uncontrolled BP the contraction of the left ventricle was stronger so in systole, the coronary blood could reverse its course, run on a retrograde direction, collide against the antegrade flow and create turbulence (1C). At the end, before deploying a vascular closure device, an iliac angiogram was performed. In Figure 2, on a black background of contrast, the blood in white color moved forward with a pointed tip of laminar flow. 0.06 seconds later, the laminar tip was stopped abruptly with all the layers recoiling on each other like a falling stack of dominoes. In the next image. a large swirl of disorganized mixing of blood and contrast suggested the presence of turbulence caused by the collision. The data to be collected were (1) the duration of the antegrade and retrograde flow, (2) duration of the collision (turbulence at the collision site) Results In the group A (BP &amp;lt;120/75 mmHg), 90% of 20 patients had no retrograde flow nor collision in the iliac and short collision in coronary arteries (&amp;lt;0.12 secs). In 30 patients of group B (BP &amp;gt;160/105 mmHg), the duration of retrograde flow and collision in the iliac artery were prolonged at &amp;gt;0.24 msecs. In the coronary arteries, the duration was prolonged at 0.18 msecs (all p&amp;lt;0.05 compared with group A). These locations of turbulence correlated with the location of plaques in our prior studies. Conclusion In patients with uncontrolled HTN, the retrograde flow was prolonged, and the turbulence was intense. In contrary, for patients with controlled BP, there was no retrograde flow and weaker collision in coronary arteries. The results suggest that a BP of &amp;lt;120/75 mmHg may not trigger the atherosclerotic process. New clinical trials with larger number of patients should be performed in search for the lowest ideal blood pressure. Funding Acknowledgement Type of funding sources: None.

Microscale pedestrian environment surrounding pedestrian injury sites in Washington state, 2015–2020

Objective While microscale pedestrian environment features such as sidewalks and crosswalks can affect pedestrian safety, it is challenging to assess microscale environment associated risk across locations or at scale. Addressing these challenges requires an efficient auditing protocol that can be used to assess frequencies of microscale environment features. For this reason, we developed an eight-item pedestrian environment virtual audit protocol and conducted a descriptive epidemiologic study of pedestrian injury in Washington State, USA. Methods We used data from police reports at pedestrian-automotive collision sites where the pedestrian was seriously injured or died. At each collision site, high school students participating in an online summer internship program virtually audited Google Street View imagery to assess the presence of microscale pedestrian environment features such as crosswalks and streetlighting. We assessed inter-rater reliability using Cohen’s kappa and explored prevalence of eight microscale environment features in relation to injury severity and municipal boundaries. Results There were 2248 motor vehicle crashes eliciting police response and resulting in death or serious injury of a pedestrian in Washington State between January 1, 2015 and May 8, 2020. Of the crashes resulting in serious injury or death, 498 (22%) resulted in fatalities and 1840 (82%) occurred within municipal boundaries. Cohen’s kappa scores for the eight pedestrian features that were audited ranged from 0.52 to 0.86. Audit results confirmed that features such as sidewalks and crosswalks were more common at collision sites within city limits. Conclusions High school student volunteers with minimal training can reliably audit microscale pedestrian environments using limited resources.

A Quantitative Method for Determining Underground Garage Parking Comfort and Development of a BIM Based Analysis Program

The current parking space design only considers whether the parking space size meets the requirements of the specification, but because of people’s parking habits, parking technology is different and its requirements for parking comfort are different, and so our parking space design should be people-oriented to meet people’s requirements for parking comfort. At present, the main dilemma faced by designers considering the comfort of parking is that it is difficult to quantify the comfort of parking. At the same time, the number of parking spaces in underground garages is large, so manual calculation of the comfort of parking is a huge task. Therefore, in this paper, we put forward the concept of parking comfort and put forward a calculation model that can quantify the parking comfort. Considering the position coordinates of the collision-prone parts in the whole process of vehicle parking, the collision position coordinates and site obstacle coordinates are established together to form the vehicle collision constraint relationship in the process of parking, so as to quantify parking comfort into specific values. At the same time, based on the calculation model and BIM secondary development technology, we develop a program for automatic calculation and detection of parking comfort based on the BIM model, so as to automatically evaluate the parking comfort of each parking space in the whole underground garage effectively, quickly, and accurately.

If you build it, will they come? A comparative landscape analysis of ocelot roadkill locations and crossing structures

Wildlife-vehicle collisions can have a substantial influence on the mortality rates of many wildlife populations. Crossing structures are designed to mitigate the impact of road mortality by allowing safe passage of wildlife above or below roads, and connect to suitable areas on both sides of the road. Ocelots (Leopardus pardalis) are a federally endangered felid in the United States, with remnant populations of <80 individuals remaining in the Lower Rio Grande Valley of South Texas. Vehicle collisions are the greatest known source of mortality for ocelots in Texas. Crossing structures designed for ocelot use have been implemented throughout South Texas since the 1990s, however, ocelots rarely use them. We compared landscape characteristics between ocelot crossing structures and ocelot-vehicle collision sites. We quantified the spatial distribution of woody and herbaceous cover types surrounding ocelot crossing structures (n = 56) and ocelot-vehicle collision sites (n = 26) at multiple spatial extents and compared landscape metrics between these location types. The landscape surrounding ocelot crossing structures had 17–22% more open herbaceous cover >1,050 m from the road, and 1.2–5.8 ha larger herbaceous patches >450 m from the road compared to ocelot-vehicle collision sites. Additionally, many crossing structures installed during the 1990’s are situated >100 km away from an extant ocelot population. Results from this study can guide conservation planners to place future road crossing structures in areas more likely to be used by ocelots. Our results also emphasize that reliable scientific data must be used for effective mitigation efforts. In the absence of data, post-installation assessments can improve the placement of future structures.

Observations of a Flare-ignited Broad Quasiperiodic Fast-propagating Wave Train

Large-scale extreme-ultraviolet (EUV) waves are frequently observed as an accompanying phenomenon of flares and coronal mass ejections (CMEs). Previous studies mainly focused on EUV waves with single wave fronts that are generally thought to be driven by the lateral expansion of CMEs. Using high spatiotemporal resolution multi-angle imaging observations taken by the Solar Dynamics Observatory and the Solar Terrestrial Relations Observatory, we present the observation of a broad quasiperiodic fast-propagating (QFP) wave train composed of multiple wave fronts along the solar surface during the rising phase of a GOES M3.5 flare on 2011 February 24. The wave train transmitted through a lunate coronal hole (CH) with a speed of ∼840 ± 67 km s−1, and the wave fronts showed an intriguing refraction effect when they passed through the boundaries of the CH. Due to the lunate shape of the CH, the transmitted wave fronts from the north and south arms of the CH started to approach each other and finally collided, leading to a significant intensity enhancement at the collision site. This enhancement might hint at the occurrence of interference between the two transmitted wave trains. The estimated magnetosonic Mach number of the wave train is about 1.13, which indicates that the observed wave train was a weak shock. Period analysis reveals that the period of the wave train was ∼90 s, in good agreement with that of the accompanying flare. Based on our analysis results, we conclude that the broad QFP wave train was a large-amplitude fast-mode magnetosonic wave or a weak shock driven by some nonlinear energy release processes in the accompanying flare.

Motorway Bottleneck Probability Estimation in Connected Vehicles Environment Using Speed Transition Matrices.

Increased development of the urban areas leads to intensive transport service demand, especially on urban motorways. To increase traffic flow and reduce congestion, motorway traffic bottlenecks caused by high traffic demand need to be efficiently resolved using Intelligent Transport Systems services. Communication technology development that supports Connected Vehicles (CVs), which act as an active mobile sensor for collecting traffic data, provides an opportunity to harness the large datasets to develop novel methods regarding traffic bottlenecks detection. This paper presents a speed transition matrix based model for bottleneck probability estimation on motorways. The method is based on the computation of the speed at the vehicle transition point between consecutive motorway segments, which forms a traffic pattern that is represented using transition matrices. The main feature extracted from the traffic patterns was the center of mass, whose position is used as an input to the fuzzy-based system for bottleneck probability estimation. The proposed method is evaluated on four different simulated motorway traffic scenarios: (i) traffic collision site, (ii) short recurring bottleneck, (iii) long recurring bottleneck, and (iv) moving bottleneck. The method achieves comparable bottleneck detection results on every scenario, with a total accuracy of 92% on the validation dataset. The results indicate possible implementation of the method in the motorway traffic environment with a high CVs penetration rate using them as the sensory input data for the control systems based on the machine learning algorithms.

Excitation of the triplet 2p4(3P)3s2 autoionizing state of Neon by molecular orbital electron promotion at solid surfaces

We address the long standing issue of the dominant excitation of the triplet 2p4(3P)3s2 state in the scattering of Neon projectiles from Magnesium, Aluminum and Silicon surfaces, which is not predicted by the Fano-Lichten Molecular orbital promotion model. We measured autoionization spectra from the triplet and the singlet states of Neon excited at Al and Mg surfaces. The measurements show that the triplet excited state is produced locally at the collision site, supporting the physical picture of an Auger rearrangement converting the singlet state into the triplet while the colliding atoms are still coupled in the quasi-molecular system.

Electrogram fractionation during sinus rhythm occurs in normal voltage atrial tissue in patients with atrial fibrillation.

Electrogram (EGM) fractionation is often associated with diseased atrial tissue; however, mechanisms for fractionation occurring above an established threshold of 0.5mV have never been characterized. We sought to investigate during sinus rhythm (SR) the mechanisms underlying bipolar EGM fractionation with high-density mapping in patients with atrial fibrillation (AF). Forty-five patients undergoing AF ablation (73% paroxysmal, 27% persistent) were mapped at high density (18562±2551 points) during SR (Rhythmia). Only bipolar EGMs with voltages above 0.5mV were considered for analysis. When fractionation (>40ms and >4 deflections) was detected, we classified the mechanisms as slow conduction, wave-front collision, or a pivot point. The relationship between EGM duration and amplitude, and tissue anisotropy and slow conduction, was then studied using a computational model. Of the 45 left atria analyzed, 133 sites of EGM fragmentation were identified with voltages above 0.5mV. The most frequent mechanism (64%) was slow conduction (velocity 0.45m/s±0.2) with mean EGM voltage of 1.1±0.5mV and duration of 54.9±9.4ms. Wavefront collision was the second most frequent (19%), characterized by higher voltage (1.6±0.9mV) and shorter duration (51.3±11.3ms). Pivot points (9%) were associated with the highest degree of fractionation with 70.7±6.6ms and 1.8±1mV. In 10 sites (8%) fractionation was unexplained. The EGM duration was significantly different among the 3 mechanisms (p=.0351). In patients with a history of AF, EGM fractionation can occur at amplitudes>0.5mV when in SR in areas often considered not to be diseased tissue. The main mechanism of EGM fractionation is slow conduction, followed by wavefront collision and pivot sites.