Reverse Splitting Research Articles

Research on Motion Path Planning Method of Live Working Robot Manipulator Based on Reverse Splitting Calculation

In the dual manipulator motion planning of live working robot, the traditional motion planning algorithm has the problems of too many turning points and non-smoothness. Therefore, this paper proposes a method of reverse splitting and local interpolation to remove redundant path nodes and optimize the motion trajectory. The working scene of overhead distribution line live working robot is simulated in MATLAB robot toolbox. The model includes manipulator R, manipulator L and overhead conductor to verify the effect of the method proposed in this paper. The results show that, the proposed method ensures that the redundant path nodes are removed on the premise of no collision between the two manipulators, which significantly improves the quality of the path.

Structural, electronic and magnetic properties of weakly correlated metal Sr2CrTiO6: a first principles study

Structural, electronic and magnetic behaviour of a less-explored material Sr2CrTiO6 has been investigated using ab initio calculations with generalized gradient approximation (GGA) and GGA + U methods, where U is the Hubbard parameter. For each of the three possible Cr/Ti cationic arrangements in the unit cell, considered in this work, the non-magnetic band structure shows distinct traits with significant flat-band regions leading to large t 2g density of states around the Fermi energy. The Cr4+ ion in Sr2CrTiO6, which is a d 2 system, shows a reverse splitting of the t 2g orbitals. The calculated hopping matrix contains non-zero off-diagonal elements between the d xz and d yz orbitals, while the d xy orbitals remain largely unmixed. A minimal tight binding model successfully reproduces the six t 2g bands around the Fermi energy. The Fermi surface shows a two-dimensional nesting feature for the layered arrangement of Cr and Ti atoms. Fixed spin moment studies suggest that the magnetism in this compound cannot be explained by Stoner’s criterion of an itinerant band ferromagnet. In the absence of Hubbard U term, the ground state is a half-metallic ferromagnet. Calculations for the anti-ferromagnetic spin arrangement show re-arrangement of orbital character resulting in (a) narrow d xz /d yz bands and sharp peaks in the density of states at the Fermi energy and (b) highly dispersive d xy bands with a broader density of states around the Fermi energy. The metallicity persists even with increasing U for both the spin arrangements, thus suggesting that Sr2CrTiO6 belongs to the class of weakly correlated metals, while the shifting of O 2p states towards the Fermi energy with U indicates a negative charge-transfer character in Sr2CrTiO6.

Hemodynamics-driven mathematical model of first and second heart sound generation.

We propose a novel, two-degree of freedom mathematical model of mechanical vibrations of the heart that generates heart sounds in CircAdapt, a complete real-time model of the cardiovascular system. Heart sounds during rest, exercise, biventricular (BiVHF), left ventricular (LVHF) and right ventricular heart failure (RVHF) were simulated to examine model functionality in various conditions. Simulated and experimental heart sound components showed both qualitative and quantitative agreements in terms of heart sound morphology, frequency, and timing. Rate of left ventricular pressure (LV dp/dtmax) and first heart sound (S1) amplitude were proportional with exercise level. The relation of the second heart sound (S2) amplitude with exercise level was less significant. BiVHF resulted in amplitude reduction of S1. LVHF resulted in reverse splitting of S2 and an amplitude reduction of only the left-sided heart sound components, whereas RVHF resulted in a prolonged splitting of S2 and only a mild amplitude reduction of the right-sided heart sound components. In conclusion, our hemodynamics-driven mathematical model provides fast and realistic simulations of heart sounds under various conditions and may be helpful to find new indicators for diagnosis and prognosis of cardiac diseases.New & noteworthyTo the best of our knowledge, this is the first hemodynamic-based heart sound generation model embedded in a complete real-time computational model of the cardiovascular system. Simulated heart sounds are similar to experimental and clinical measurements, both quantitatively and qualitatively. Our model can be used to investigate the relationships between heart sound acoustic features and hemodynamic factors/anatomical parameters.

Origin of the magnetic and orbital ordering in α−Sr2CrO4

Motivated by recent experimental progress in transition metal oxides with the ${\mathrm{K}}_{2}\mathrm{Ni}{\mathrm{F}}_{4}$ structure, we investigate the magnetic and orbital ordering in $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Sr}}_{2}\mathrm{Cr}{\mathrm{O}}_{4}$. Using first-principles calculations, first we derive a three-orbital Hubbard model, which reproduces the ab initio band structure near the Fermi level. The unique reverse splitting of ${t}_{2g}$ orbitals in $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Sr}}_{2}\mathrm{Cr}{\mathrm{O}}_{4}$, with the $3{d}^{2}$ electronic configuration for the ${\mathrm{Cr}}^{4+}$ oxidation state, opens up the possibility of orbital ordering in this material. Using real-space Hartree-Fock for multiorbital systems, we constructed the ground-state phase diagram for the two-dimensional compound $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Sr}}_{2}\mathrm{Cr}{\mathrm{O}}_{4}$. We found stable ferromagnetic, antiferromagnetic, antiferro-orbital, and staggered orbital stripe ordering in robust regions of the phase diagram. Furthermore, using the density matrix renormalization group method for two-leg ladders with the realistic hopping parameters of $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Sr}}_{2}\mathrm{Cr}{\mathrm{O}}_{4}$, we explore magnetic and orbital ordering for experimentally relevant interaction parameters. Again, we find a clear signature of antiferromagnetic spin ordering along with antiferro-orbital ordering at moderate to large Hubbard interaction strength. We also explore the orbital-resolved density of states with Lanczos, predicting insulating behavior for the compound $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Sr}}_{2}\mathrm{Cr}{\mathrm{O}}_{4}$, in agreement with experiments. Finally, an intuitive understanding of the results is provided based on a hierarchy between orbitals, with ${d}_{xy}$ driving the spin order, while electronic repulsion and the effective one dimensionality of the movement within the ${d}_{xz}$ and ${d}_{yz}$ orbitals driving the orbital order.

Superiorization vs. accelerated convex optimization: The superiorized / regularized least-squares case

We conduct a study and comparison of superiorization and optimization approaches for the reconstruction problem of superiorized/regularized least-squares solutions of underdetermined linear equations with nonnegativity variable bounds. Regarding superiorization, the state of the art is examined for this problem class, and a novel approach is proposed that employs proximal mappings and is structurally similar to the established forward-backward optimization approach. Regarding convex optimization, accelerated forward-backward splitting with inexact proximal maps is worked out and applied to both the natural splitting least-squares term/regularizer and to the reverse splitting regularizer/least-squares term. Our numerical findings suggest that superiorization can approach the solution of the optimization problem and leads to comparable results at significantly lower costs, after appropriate parameter tuning. On the other hand, applying accelerated forward-backward optimization to the reverse splitting slightly outperforms superiorization, which suggests that convex optimization can approach superiorization too, using a suitable problem splitting.

An examination of the survivability of reverse stock splits

Purpose– The purpose of this paper is to examine the survivability of 810 reverse splits during the 1995-2006 period and show that companies that undertake reverse stock splits often fail within a relatively short time following the split.Design/methodology/approach– Applying both a logit model and an adapted version of the Hensleret al.(1997) accelerated failure time model to 810 reverse splits during the 1995-2006 period, the authors are the first to study the survivability of reverse split companies.Findings– The paper finds that the market reaction to the reverse split on the ex-date is an important predictor of the likelihood of survival and of survival time. The paper finds that the likelihood of survival also depends on firm size, pre-split firm returns, and the post-split share price level. The paper finds that post-split survival time also depends on firm size, pre-split operating performance as measured by return on assets, pre-split firm returns, leverage, and the post-split share price level.Practical implications– The study may be of interest to investors considering investing in stocks that have undergone reverse splits.Originality/value– The research sheds light on which reverse splitting firms are most likely to survive and for how long.

S-wave splitting from records of local micro-earthquakes in West Bohemia/Vogtland: An indicator of complex crustal anisotropy

Most S-wave particle motions of local micro-earthquakes in the West Bohemia/Vogtland region display S-wave splitting. The split S waves are usually well defined, being separated in time and polarized in roughly perpendicular directions in the horizontal projection. In most cases, the polarization of the fast S wave is aligned NW-SE (referred to as “normal splitting”), which is close to the direction of the maximum horizontal compression in the region. However, for some ray directions, the polarization of the fast S wave is aligned NE-SW (referred to as “reverse splitting”). The pattern of normal/reverse splitting on a focal sphere is station-dependent, indicating the presence of inhomogeneities in anisotropy. For some stations, the normal/reverse splitting pattern is asymmetric with respect to the vertical axis, indicating the symmetry axes of anisotropy are probably inclined. The presence of inclined anisotropy is confirmed by observations of directionally dependent delay times between split S waves. A complex and station-dependent anisotropy pattern is probably the result of a complicated anisotropic crust characterized by diverse geological structures. The spatial variation of anisotropy probably reflects the presence of a variety of different types of anisotropic rocks in the region.

Why Firms Consolidate Their Stocks?

I use event date methodology to examine the market reaction to reverse stock splits. I find that the abnormal returns around the announcement date are negative both for the whole reverse split sample and for the pure reverse split sample. I conduct a matched sample as the benchmark to valuate the performance of reverse splitting firms. Their firm performance and long run stock performance are documented worse compared with their matched firms. And the reverse splitting firms conducting a capital reduction perform even worse both in the view of announcement effect and of their firm performance. The adjusted trading volume increases considerably after reverse splits. This result partially suggests that reverse stock splits improve the liquidity of the stock. The relative tick size, which affects the transaction cost, decreases significantly after splitting. The relationship between the decision on split factor and the deviation from market-wide average stock price is not statistically significant. Therefore, the result does not support the hypothesis of 'optimal stock price range'.

Do reverse stock splits indicate future poor stock performance?

There has been much written on the individual topics of bankruptcy prediction, corporate performance, and forward/reverse stock splits. However, there is little research into the relationship between reverse stock splits and subsequent corporate performance and the potential for bankruptcy. Previous research suggested there is a negative drift in stock prices following reverse splits. The purpose of this study is to provide and empirically support rationales for reverse splits by classifying reverse splitting firms into two groups. The presumed rationales for engaging in reverse splits would differ between the two groups, so do the subsequent stock performance. Our results show that both neural networks and Z-scores can successfully distinguish the two groups of firms while neural networks outperforms Z-scores in finding the firms with best performing stocks.

Fortnightly Review: A MEMORABLE WARD ROUND

As a medical student in training much emphasis is placed on the detection of physical signs. This potentially can lead to feelings of inadequacy when you fail to hear the reverse splitting of the second heart sound which is so obvious to the …

An investigation of the second heart sound in the normal horse

The second heart sound was evaluated in conscious, normal horses using intracardiac and external sound detection devices and echocardiography. The second heart sound (S2) in the normal horse is single or split by a narrow interval, not usually detected by external phonocardiographic evaluation. Splitting of S2 was classified as normal (aortic [A2] preceding pulmonic [P2] components) in 66.7 per cent and reversed (P2 preceding A2) in 33.3 per cent of the horses studied. Normal splitting appears to result from lower impedance of the pulmonary vasculature delaying the onset of P2. Reverse splitting appears to result from a delay in A2 resulting from prolongation of PEP and LVET. There does not appear to be variation in splitting of S2 due to respiration based on the cases in which this was measured.

The Price Impact of Reverse Splits

> If, in principle, reverse splitting of common shares has no impact on the value of a firm, why do a large number of such splits occur every year? There are three possible reasons. First, managements may use reverse splitting to reduce their registrars' fees and shareholder mailing costs. Since it is unlikely, however, that the minimal future benefits to be gained would in most cases offset the immediate costs involved, this rationale deserves little consideration. Second, managements may use reverse splits to improve share marketability-the ease and speed with which a buyer can find a seller and vice versaby maneuvering share prices into some range perceived as preferable to investors. To test whether reverse splits can improve share marketability, the authors segregated their data into three groups(1) stocks with post-split prices in the split month of less than five dollars, (2) stocks with post-split prices between five and 15 dollars and (3) stocks with post-split prices over $15. They detected no significant differences between the groups in either split month or post-split month price movements. Third, managements may use reverse splits as an informal device for conveying to shareholders information about a firm's future earnings' prospects or dividend policies. According to the authors' findings, price behavior of dividend and non-dividend paying companies did not differ significantly. On the other hand, both types of companies saw their share prices deteriorate significantly during the month of the split: If reverse splits convey any information to shareholders, it is evidently negative. P

Mechanism of changes in the second heart sound in aortic stenosis

The dynamic correlates of the second heart sound were studied by right and left heart catheterization in 15 subjects with pure aortic valve stenosis and in 6 subjects who had no cardiac lesion. The duration of left ventricular systole is not, as previously thought, prolonged in aortic stenosis. Left ventricular ejection is prolonged because of late closure of the aortic valve related to the higher level of left ventricular pressure compared to that of aortic pressure (pressure gradient). In addition, there is a delay in the time of occurrence of the aortic incisura in relation to valve closure. The sum of both these delays (aortic valve closure in relation to end of systole; incisura in relation to valve closure) explains the delay of the aortic component of the second heart sound, which occurs either at the time of the pulmonary component or after it (reverse splitting). The changes of the second heart sound were found to be grossly proportional to the magnitude of the pressure gradient across the aortic valve and, therefore, significant in evaluating the severity of the lesion.

The second heart sound in normal and abnormal conditions

Changes of the second heart sound are caused by shifting in position and changes in magnitude of the aortic or pulmonary component, or both. Differences in the magnitude of each component are primarily related to changes in pressure but are also affected by structural changes of the vascular walls. Positional changes are influenced by the time of closure of the respective valve (in turn related to time of ventricular activation, duration of systole and pressure gradient across the valve) and by the interval between valve closure and vascular vibration at the time of rebound. Normal splitting is present during inspiration and decreases or disappears during expiration. Marked differences related to age are present. Three abnormalities may occur: wide splitting during inspiration that persists during expiration; single second sound; and reverse splitting, either occurring only during, or accentuated by, expiration (occasionally also occurring during inspiration).

The Q-II interval. 3. A study of the second heart sound in old age.

AbstractA study of the intervals between the onset of QRS and the aortic (IIA and pulmonic (IIP) components of the second heart sound was made in 16 subjects between 70 and 92 years of age. A group tendency toward prolongation of both Q‐IIA and Q‐IIP was found. The relatively greater prolongation of left over right ventricular systole or vice versa gave rise to reverse‐type splitting (25 per cent) or a single second sound (38 per cent) respectively; normal splitting was found in 37 per cent of the cases.The various possible causes of prolongation of these intervals are discussed. As neither diastolic hypertension nor severe ischemic heart disease was present in the group with reverse splitting, this manifestation would seem to be the result of the process of aging. Prolongation of the pre‐ejection period was an important contributory factor in some cases.On the basis of these findings, new formulas were developed for prediction of Q‐IIA and Q‐IIP which would be applicable to elderly persons.

New non-linear photon-magnon interaction under parallel pumping in Yig

We describe the characteristics of an anomalous process of parametric magnons excitation under parallel pumping, when a single crystal YIG is subjected to a c.w. microwave field at X band. We observe an avalanche phenomenon of the power absorbed by the crystal when the amplitude of the r.f. field exceeds a threshold if the d.c. field is below 1350 Oe. Using the theory of the dipolar transitions of spin-waves we attribute the origin of this new mechanism to a non-linear damping of the parametric magnons due to direct fusion and reverse splitting of spin-waves.