Terminal Vector Research Articles

ECG at the Bedside: Atrial Bigeminy with Alternating long and Short PR Interval

The admission electrocardiogram of an 88-year-old woman, showed sinus rhythm, biphasic P waves in leads II, III, with the terminal vector directed upward, P duration 130 msec, PR interval 200 msec, consistent with advanced inter-atrial block. Next, atrial bigeminy occurred originating in the left atrium and delaying the sinus P waves. With the ectopic P’ measuring 60 msec, the likely path of left atrial stimuli to delaying the sinus node was through Bachmann’s bundle, by retrograde conduction. This means that inter-atrial conduction via Bachmann bundle.

Monoribbed‐Functionalized Macrobicyclic Iron(II) Complexes Decorated with Terminal Reactive and Vector Groups: Synthetic Strategy, Chemical Transformations and Structural Characterization

Comprehensive SummaryGeneral and straightforward synthetic strategy towards the iron(II) clathrochelates with functionalizing substituents in their apical capping and one of the three chelate ribbed fragments was developed. Their hexachloroclathrochelate precursors were prepared by the direct template condensation of dichloroglyoxime with a suitable boronic acid on the Fe2+ ion as a matrix and underwent a stepwise nucleophilic substitution with S2‐, N2‐ or O2‐bis‐nucleophiles, forming the alicyclic or aromatic N2‐, S2‐ or O2‐six‐membered fragments. Depending on the reaction conditions and precursor‐to‐dinucleophile molar ratios, iron(II) clathrochelates with one (S, O and N), two (S, O and N) or three (S and O) X2‐six‐membered ribbed substituent(s) were obtained. Their reactivity substantially decreases in a row: Cl6‐Cage > Cl4X2‐Cage (where X = S, O or, especially, N) > Cl2X4‐Cage (where X = S or O). The reactive monoribbed‐functionalized clathrochelates underwent further chemical transformations giving the target macrobicyclic complexes with terminal vector groups. As follows from the single crystal XRD data, their FeN6‐coordination polyhedra possess the geometry intermediate between a trigonal prism and a trigonal antiprism (φ = 21.3°—25.20°). Fe—N distances vary from 1.887(6) to 1.933(8) Å. Their 3D‐molecules, the hydrophobic–hydrophilic balance in which can be tuned using a ribbed functionalization, form in the crystals the intermolecular specific halogen bonds and/or hydrophobic interactions.

Improving the search accuracy of differential evolution by using the number of consecutive unsuccessful updates

During the process of evolution, feedback information is frequently utilized to guide the following search and it has been proved to be very effective. However, the information of unsuccessful updates has not been fully utilized yet. Thus, it is important to exploit this information systematically, which will provide a reference for further researches. In this paper, we use the number of consecutive unsuccessful updates ciG to improve the search accuracy of differential evolution (DE) and propose a novel type of DE variant, called as consecutive unsuccessful updates-based DE (CUSDE). There are two operations in CUSDE. Firstly, a simple but efficient mutation strategy is developed, in which the base vector and terminal vector are selected based on the probability calculated from ciG. Secondly, a deletion mechanism is proposed to adaptively remove some inferior individuals with larger ciG values. Compared with other state-of-the-art DE variants on CEC 2005 and CEC 2017 benchmark sets, the experimental results confirm the superiority of CUSDE in improving the search accuracy.

Electrocardiographic biomarkers to predict atrial fibrillation in sinus rhythm electrocardiograms

ObjectiveEarly prediction of atrial fibrillation (AF) development would improve patient outcomes. We propose a simple and cheap ECG based score to predict AF development.MethodsA cohort of 16 316 patients was...

Optimal Cooperative Guidance Laws for Two UAVs Under Sensor Information Deficiency Constraints

This paper presents closed-form optimal cooperative guidance laws for two UAVs under information constraints that achieve the required relative approach angle. Two UAVs cooperate to optimize a common cost function under a coupled constraint on terminal velocity vectors and the information constraint which defines the sensor information availability. To handle the information constraint, a general two-player partially nested decentralized optimal control problem is considered in the continuous finite-horizon time domain. It is shown that under the state-separation principle the optimal solution of the decentralized control problem can be obtained by solving two centralized subproblems which cover the prediction problem for the information-deficient player and the prediction error minimization problem for the player with full information. Based on the solution of the decentralized optimal control problem, the explicit closed-form cooperative guidance laws that can be efficiently implemented on conventional guidance computers are derived. The performance of the proposed guidance laws is investigated on both centralized and decentralized cooperative scenarios with nonlinear engagement kinematics of networked two-UAV systems.

Investigation on Dynamic Response of Grid-Tied VSC During Electromechanical Oscillations of Power Systems

This study focuses on the dynamics of a grid-tied voltage source converter (GVSC) during electromechanical oscillations. A small-signal model with GVSC port variables (DC voltage and AC power) as the outputs and a terminal voltage vector as the input is derived to reveal the passive response of the GVSC on the basis of the power equation in the d–q coordinate system. An input–output transfer function matrix is constructed according to the proposed model. The frequency response of this matrix in the electromechanical bandwidth is described to reflect the dynamic behavior of the GVSC. The effects of the operation parameters, i.e., the grid strength, reference value of the control system, and grid voltage, on the dynamic behavior of the GVSC in the electromechanical bandwidth, are investigated using frequency domain sensitivity. Analysis results show that the GVSC generates responses with respect to the electromechanical mode. These responses have different sensitivities to the operation parameters. The IEEE 10-machine power system simulation is performed, and the power hardware-in-the-loop platform with the GVSC was applied to validate the analysis.

On the solution to every Lambert problem

Lambert’s problem is the two-point boundary value problem for Keplerian dynamics. The parameter and solution space is surveyed for both the zero- and multiple-revolution problems, including a detailed look at the stress cases that typically plague Lambert solvers. The problem domain, independent of formulation, is shown to be rectangular for each revolution case, making the elusive initial guess and the solution itself amenable for interpolation. Biquintic splines are implemented to achieve continuous derivatives and quick evaluation. Resulting functions may be used directly as low-fidelity solutions or used with a single update iteration without safeguards. A concise, improved vercosine formulation of the Lambert problem is presented, including new singularity-free and precision-saving equations. The interpolation scheme is applied for up to 100 revolutions. The domain considered includes all practically conceivable flight times, and every possible geometry except a small region near the only physical singularity of the problem: the equal terminal vector case. The solutions are archived and benchmarked for accuracy, memory footprint, and speed. For typical scenarios, users can expect $$\sim 6$$ or more digits of velocity vector accuracy using an interpolated solution without iteration. Using a single, unguarded iteration leads to solutions with near machine precision accuracy over the full domain, including the most extreme scenarios. Depending on desired resolution, coefficient files vary in size from $$\sim 3$$ to 65 MB for each revolution case. Evaluation runtimes vary from $$\sim 2$$ to 5 times faster than the industry benchmark Gooding algorithm. The coefficient files and driver routines are provided online. While the method is currently demonstrated on the vercosine formulation, the 2D interpolation scheme stands to benefit all Lambert problem formulations.

Algorithm of the Time-Optimal Reorientation of an Axially Symmetric Spacecraft in the Class of Conical Motions

The problem of the time-optimal turn of a spacecraft as a rigid body with one axis of symmetry and bounded control function in absolute value is considered in the quaternion statement. For simplifying problem (concerning dynamic Euler equations), we change the variables reducing the original optimal turn problem of axially symmetric spacecraft to the problem of optimal turn of the rigid body with spherical mass distribution including one new scalar equation. Using the Pontryagin maximum principle, a new analytical solution of this problem in the class of conical motions is obtained. Algorithm of the optimal turn of a spacecraft is given. An explicit expression for the constant in magnitude optimal angular velocity vector of a spacecraft is found. The motion trajectory of a spacecraft is a regular precession. The conditions for the initial and terminal values of a spacecraft angular velocity vector are formulated. These conditions make it possible to solve the problem analytically in the class of conical motions. The initial and the terminal vectors of spacecraft angular velocity must be on the conical surface generated by arbitrary given constant conditions of the problem. The numerical example is presented. The example contain optimal reorientation of the Space Shuttle in the class of conical motions.

Preexcitation syndrome: experimental study on the electrocardiogram of antegradely conducting accessory pathway

BackgroundPreexcitation syndrome is characterized by a dominant delta wave on the baseline electrocardiogram (ECG), resulting from the change in QRS initial vector by the accessory pathway (AP). This study is to explore the effect of ventricular preexcitation on the QRS initial, maximal and terminal vector in an experimental rabbit with preexcitation syndrome induced by programmed electrical stimulation.MethodsRabbits (n = 10) were randomized for the experimental model of ventricular preexcitation. Sensing and stimulating electrode catheters were placed in the high right atrium and along epicardial surface of atrioventricular groove of the left ventricular anterior wall, respectively. Programmed premature stimulation S2 was synchronized with P wave and utilized to stimulate the ventricle. The ECG recorded the electrical activity of the heart. As compared with the QRS complex during sinus rhythm, paced QRS was assessed regarding the initial, maximal and terminal vector. PS2 interval and PR interval were also measured and analyzed.ResultsPreexcitation was successfully simulated by ventricular pacing in the rabbits, including (1) Complete preexcitation: PS2 interval was less than PR interval; the difference was more than or equal to 47.00 ± 7.53 ms. (2) Incomplete preexcitation: PS2 interval was less than PR interval; the difference was less than 47.00 ± 7.53 ms. (3) Incomplete latent preexcitation: PS2 interval was more than or equal to PR interval; the difference was less than or equal to 13.00 ± 3.50 ms. (4) Complete latent preexcitation: PS2 interval was more than or equal to PR interval; the difference was more than 13.00 ± 3.50 ms.ConclusionsThe difference in the relative conduction velocity of the atrioventricular node versus the AP pathways determines the degree of preexcitation and different manifestation on ECG. The QRS terminal vector also reflects the ventricle preexcitation, indicating a valuable sign for the diagnosis of atypical or latent preexcitation.

On the existence of optimal strategies in the control problem for a stochastic discrete time system with respect to the probability criterion

We study a control problem for a stochastic system with discrete time. The optimality criterion is the probability of the event that the terminal state function does not exceed a given limit. To solve the problem, we use dynamic programming. The loss function is assumed to be lower semicontinuous with respect to the terminal state vector, and the transition function from the current state to the next is assumed to be continuous with respect to all its arguments. We establish that the dynamic programming algorithm lets one in this case find optimal positional control strategies that turn out to be measurable. As an example we consider a two-step problem of security portfolio construction. We establish that in this special case the future loss function on the second step turns out to be continuous everywhere except one point.

Accuracy Analysis of the Analytical Solution for the Lunar Lander Terminal Guidance Problem

An analysis of the accuracy and reliability of the proposed analytical solution for the lunar lander terminal guidance problem was carried out. The analytical solution for 3D terminal guidance problem was obtained for a constant acceleration trajectory and thrust vector orientation programs, which are essentially linear with time. In order to achieve 6 terminal conditions (position and velocity terminal vector components) 6 guidance law parameters were used: time-to-go, braking deceleration, initial pitch angle and pitch rate, initial yaw angle and yaw rate. The simulation results of the lunar lander terminal guidance using the proposed analytical solution were presented. The analysis of the proposed terminal guidance scheme and some similar schemes were carried out by mathematical modeling of the landing maneuver from a certain initial state to the desired spot near the lunar surface. By varying the initial position and the velocity parameters, when the terminal point was fixed, the statistic characteristics of the terminal guidance solution errors in the terminal position and velocity were estimated. An analysis of the simulation results validates the basic performance of the proposed terminal guidance scheme for the lunar pinpoint landing. Estimates of the terminal guidance accuracy for the proposed scheme exceed the corresponding estimates for the alternative considered schemes. The next phase of this research will be intended for studying the influence of variations in the initial prelanding orbit parameters (obliquity, ascending node longitude, argument of periapsis, periapsis height, apoapsis height) on the terminal guidance accuracy.

Effects of Antegrade Accessory Pathway Conduction on QRS Terminal Vector in Patients with Preexcitation Syndrome.

Ventricle preexcitation through accessory pathway changes QRS initial vector, and manifests as delta wave on electrocardiogram (ECG). However, QRS terminal vector can also be affected. A total of 158 patients who had single accessory pathway (AP) with antegrade conduction capacity were included and divided into two groups according to the ECG with or without delta wave. Note that 150 patients had delta wave (overt AP group) on ECG; classical preexcitation syndrome was diagnosed before radiofrequency ablation. Eight patients had no delta wave on ECG (unapparent AP group); preexcitation was induced by transesophageal atrial pacing. ECGs and intracardiac electrogram (IEGM) before and after ablation and during atrioventricular reentrant tachycardia were analyzed. (1) In the overt AP group: QRS terminal vector amplitude and polarity changes were observed in all the 150 patients, and were related to AP location and delta wave polarity. (2) In the unapparent AP group: QRS terminal vector changes were found in two out of eight patients, and the initial activation of ventricle myocardium via AP on IEGM was almost simultaneous with the onset of QRS complex on ECG. It is not only the QRS initial vector, but also the QRS terminal vector that can be changed by the antegrade accessory pathway conduction in patients with preexcitation syndrome. The change of QRS terminal vector is valuable for the diagnosis of atypical preexcitation.

Effects of Preexcitation Syndrome on Terminal QRS Vector Observed in Spatial Vector.

Preexcitation syndrome could affect terminal QRS vector, which is not emphasized in clinic. In this study, we made a comparison between vectorcardiogram (VCG) before and after ablation to observe the change of terminal QRS vector. Furthermore, the relationship between the change of terminal QRS vector and accessory pathway (AP) as well as the change of initial QRS vector (delta vector) was analyzed. Thirty patients who were proved to have a single AP by ablation were included. All patients were divided into seven groups based on the AP location. Comparison between VCG before and after ablation was made to observe the change of terminal and delta vector. The relationship between the change of terminal QRS vector and AP location as well as delta vector was analyzed. (1) All 30 patients had a change in terminal QRS vector (elevation and/or azimuth) in comparison to postablation VCG. (2) The change of terminal QRS vector was related to delta vector and AP location. The agreement and consistency between the change of terminal QRS vector and delta vector were 91.65% and 0.856 (P < 0.01), respectively. (1) Both initial and terminal QRS vector are affected by the antegrade conduction of AP. The change of terminal QRS vector is related to the AP location and delta vector. (2) The effect of preexcitation syndrome on QRS terminal vector is shown as more intuitive and easy in spatial vector by comparison with electrocardiogram, which is helpful for the diagnosis of atypical preexcitation and localization of AP.

A Model of Predicting Corrosion Rate for Substation Grounding Grid Based on the Similarity and Support Vector Regression

In this paper, we proposed a training model to predict the corrosion rate for substation grounding grid based on the Similarity and Support Vector Regression (SSVR). In the proposed model, the effect of grounding grid corrosion rate was acted as a feature vector and processed by a dimensionless treatment. Then, the similarity between the feature vector of training terminal and index vector of actual site would be calculated. In the prediction of corrosion rate, the traditional Linear Average Method (LAM) to describe the nonlinear contribution has some fault defects. Therefore, we proposed the training model named SSVR. From the experimental results, the proposed SSVR can obtain better predicting performance than the traditional LAM.

Fusion of biventricular incomplete bundle branch block, in healthy young adults and in patients with moderate pulmonary hypertension. Fragmented depolarization – a new real ECG entity

Introduction: Within the QRS complex, the vector components either compete with each other or can appear at the same time. The two best examples of rewriting the original ECG curves are preexcitation and complete left bundle branch block. In contrast, the rS complex of left anterior hemiblock (LAH) and the Q wave of postero-inferior myocardial infarction (PI MI) can be observed simultaneously forming a W complex in the inferior leads. Methods: First, variants of incomplete right bundle branch blocks (IRBBB) were studied in healthy young adults and in patients with moderate pulmonary hypertension. According to the QRS morphology in the frontal plane (59 patients), three IRBBB patterns were formed: 1. SI-SII-SIII (n = 20); 2. SI-QIII (n = 18); 3. Both 1 and 2 patterns (n = 8). Presence or absence of IRBBB signs in lead V1 was meanwhile registered. Secondly, two further patterns were formed relating to comparison of biventricular incomplete blocks with arborization block. Both are characterized by depolarization inhomogeneity. 4. IRBBB + LAH (n = 11); 5. IRBBB + LAH + PI MI (n = 2). Results: In pattern 3, initial and terminal vectors (QIII-SIII) occurred simultaneously in the ECG lead III. Frequently, waves occurring in the same period of the depolarization in certain leads remained separable (two-component S-wave). In pattern 4, after the initial “r” wave, a two component S wave (rW complex) appeared in the inferior leads. Such separation of the depolarization vector components does not mean high electrical inhomogeneity if the width of QRS remains under 110 ms. In pattern 5, the ventricular depolarization is fragmented, and appears as three negative waves in the inferior leads (VW complex). In these cases, the duration of ventricular depolarization is also not wider than 110 ms. In contrast, the arborization block is characterized by fragmented depolarization, but the duration of QRS is wider than 140 ms, resulting in extreme inhomogeneity. Conclusion: By wave form analysis of biventricular incomplete blocks, we could describe a new ECG entity, of less dangerous “arborization block-like” form.

Transgene expression in the mouse cerebellar Purkinje cells with a minimal level of integration using long terminal repeat-modified lentiviral vectors

Transgene expression in the mouse cerebellar Purkinje cells with a minimal level of integration using long terminal repeat-modified lentiviral vectors

$\Bbb L^2$ Sufficient Conditions for End-Constrained Optimal Control Problems With Inputs in a Polyhedron

An $\hbox{{\bbb L}}^2$-local optimality sufficiency theorem is proved for a class of structured infinite-dimensional nonconvex programs with constraints of the form $u\in\Omega$ and h(u)=0, where $\Omega$ is a set of Lebesgue measurable essentially bounded vector-valued functions $u(\cdot ): [0,1]\rightarrow \hbox{{\bbb R}}^m$ with range in a polyhedron U, and h is a smooth map of the space of essentially bounded functions $u(\cdot )$ into ${\bbb R}^k$. The sufficiency theorem is based on formal counterparts of the finite-dimensional Karush--Kuhn--Tucker sufficient conditions in a Cartesian product of polyhedra, a strengthened variant of Pontryagin's necessary condition, and structure and continuity conditions on the first and second differentials of the objective function and equality constraint functions. The new sufficient conditions are directly applicable to nonconvex continuous-time Bolza optimal control problems with control-quadratic Hamiltonians, unqualified affine inequality constraints on vector-valued control inputs, and equality constraints on the terminal state vector or equivalent isoperimetric constraints on integrals of functions depending on the state and control variables.

The single-crystal electron spin resonance spectra of bis chloro bis(N,N′-substituted urea)oxovanadium(IV) compounds diluted in the corresponding tris-chloro bis(N,N′-substituted)urea indium(III) compounds

Abstract Single crystal ESR spectra of VOCl 2 L 2 (where L = N , N , N ′, N ′-tetramethyl urea (tmu), N , N ′-dimethylethyleneurea, N , N ′-dimethylpropyleneurea, tris(dimethylamino)phosphincoxide) diluted in the corresponding Inocl 3 L 2 , at Q-band frequencies are reported. The ESR data are consitent with C 2 point symmetry for VOCl 2 (tmu) 2 whilst the other compounds approximate very closely to this point symmetry. A rotation of the g and A tensor axes in the plane perpendicular to the terminal VO vector fall in the range 8–15° for the four compounds studied. The spin Hamiltonian parameters for VOCl 2 (tmu) 2 , in conjunction with the published polarized electronic absorption spectra, have been analysed via angular overlap calculations. For VOCl 2 (tmu) 2 unusual ligand hyperfine splittings were observed. These were analysed by spectrum simulation in terms of two equivalent chlorine atoms where the chlorine hyperfine and nuclear quadrupole tensors are of comparable magnitude.

On the construction of the matching polynomial for unbranched catacondensed benzenoids

AbstractAn algorithm for obtaining the matching polynomial of an arbitrary catacondensed unbranched benzenoid molecule is presented. It is based on multiplication of only three 5 x 5 transfer matricesI,J,K, and an appropriate terminal vector. The choice of the matrices is dictated by the history of the growth of the hexagonal “animals” (i.e., by the pattern of the successive fusions of the benzene rings). The approach also gives the number of Kekule valance structures, the count of conjugated circuits, the values of the topological indexZ, and the characteristic polynomials.

Response of coupled one‐dimensional dynamic systems

Attention is focused on a complex of one‐dimensional dynamic systems. The extent of a dynamic system is defined in terms of two terminal positions, one at each of two junctions. A terminal vector per junction can thus be constructed. The propagation in a dynamic system is defined in terms of two propagation functions each describing the propagation toward one or the other junction. A diagonal propagation matrix per junction can thus be constructed. The coupling among the dynamic systems is defined in terms of two junction matrices. The external drive at a position on a given dynamic system is defined in terms of the responses that it initiates toward one junction and toward the other junction. With this model and definitions of a complex of coupled one‐dimensional dynamic systems one may appropriately derive the various component matrices of the impulse response matrix. The matrix yields the response of the complex to the appropriately defined external drive vector. The derivation is explained and discussed. The basic (exponential‐type) propagation forms and the nonbasic (e.g., Bessel functional‐type) propagation forms are contrasted. The utility of the formalism is briefly cited and discussed.