Dissipation induced quantum synchronization in few-body spin systems

We explore the synchronization phenomenon in quantum few-body spin system with the non-local dissipation by quantum trajectory approach. We find that even without external drive, the system can achieve spontaneous synchronization due to the interaction of non-local dissipation, and the time-dependent non-stationarity oscillations can be confirmed through the purely imaginary eigenvalues of the Liouvillian. We theoretically analyze the dissipative dynamics of the system and consider the measure to quantify synchronization through the stochastic quantum trajectories. In each quantum trajectory, it is also possible for the system to ignore dissipative process and build up oscillations in the long-time evolution. We finally investigate the robustness of the oscillations to perturbations, and determine the so-call the largest Lyapunov exponent to confirm the stability of oscillations.Comment: 8 pages, 5 figure

Quantum non-stationary phenomena of spin systems in collision models

We investigate the non-stationary phenomenon in a tripartite spin-1/2 system in the collision model (CM) framework. After introducing the dissipation through the system-environment collision for both Markovian and non-Markovian cases, we find the emergence of long-time oscillation in the dynamics of the system and the synchronization among subsystems. We connect the CM description and the quantum master equation in the continuous time limit and explain the existence of the stable oscillation by means of Liouvillian spectrum analysis. The time-dependence of the thermal property and the correlations are investigated, in particular we discuss the possibility of violation of the Landauer's principle in non-Markovian dynamics. In addition, we find that the imperfection of collective dissipation can be compensated by the randomness of the interaction sequence in our CM.Comment: 13 pages, 8 figures, accepted versio

A modified coupled map car-following model considering a nonconstant driver sensitivity

AbstractOwing to the real traffic in which the drivers’ sensitivities are different under different speeds and road conditions, a modified car-following model is put forward. This model is related to the headway of cars and the velocity difference as well as the variation of the sensitivity. A small parameter is added to the original sensitivity. Based on the stability theory of Hurwiz, the allowable variation range of this parameter, especially in the case of different velocities, is obtained. It can be concluded that the model with the term of velocity difference can increase the stability of traffic flow

Reaktionen auf Hitzestress und funktionelle Analyse von LIM6 und LIM14 in den späten Stadien der Pollenentwicklung bei Mais

Male gametophyte development in flowering plants undergoes a complex process that is transcriptionally regulated and that it is highly sensitive to abiotic and biotic stresses. Particularly, developmental phase transitions of plant reproduction play a crucial role in normal gametophyte generation and successful double fertilization. In maize, the diploid pollen mother cell (2N) releases haploid microspores (1N) after meiosis. Following two rounds of mitosis, pollen development phases are defined based on the developmental state of nuclei, which include the unicellular, bicellular, and tricellular stages. When a moderate (35°C/25°C day/night) heat stress treatment was imposed on maize plants at the unicellular and bicellular stages, pollen showed stage-specific heat stress responses (HSR). During unicellular development, pollen viability and fertilization ability were severely affected, resulting in reduced seed set. However, at the bicellular stage, heat stress did not have strong effects on pollen abilities, but still caused seed abortion. Furthermore, sperm cells were found strongly altered both in morphology and biological functions. Through transcriptome and proteome profile analyses, the metaphase of mitosis during PMII was found partially arrested, resulting in the generation of nonfunctional sperm cells. Meanwhile, sperm cells could not travel into the pollen tube for fertilization, probably due to heat stress impairing pollen tube cytoskeleton structure. Two LIM transcription factors genes, ZmLIM6 and ZmLIM14, are highly expressed during the bicellular and tricellular pollen stages. CRISPR/Cas9 knock-out mutants of ZmLIM6/14 produced one sperm-like nucleus or sperm cells were not observed inside the mature pollen. In addition, pollen tubes grew in a twisted pattern. Inside the pollen grain, LIM6/14 colocalized with α-tubulin. Therefore, in LIM-mutated pollen, α-tubulin failed to form a normal envelope. However, tubulin disorder and nuclei loss were independent by investigating the LIM-mutated sperm cell marker line, YFP-tubulin+/lim14. Moreover, ZmLIM6/14 proteins functioned during nucleolus formation in germ cells, which was likely explained by the lim6/14 phenotypes. Further, ZmRALF3 was identified as the potential target of ZmLIM14 and thus regulating pollen tube integrity. Altogether, all findings reveal multiple functions of ZmLIMs in proper microtubule bundling and nucleoli formation during the bi- to tricellular transition stage in maize pollen. In general, above findings indicate that heat stress affects sperm cell formation during the PMII transition in pollen development. Moreover, it is revealed that the novel functions of ZmLIMs in microtubule dynamics and sperm cell formation during the PMII transition. In conclusion, this thesis provides more evidences for male gametophyte phase-specific regulation patterns and more insights into the late stages of maize pollen development

The determinants of IPO-related Shareholder Litigation : the role of CEO equity incentives and corporate governance

This paper empirically examines whether CEO equity incentives as well as other corporate governance mechanisms are related to the incidence of shareholder litigation. Our study differs from previous studies, which have largely focused on seasoned firms, by examining how CEO incentives at a firm's pre-IPO stage affect the incidence of IPO-related shareholder litigation. We examine a sample of 81 U.S. IPO firms (issued between 1997 and 2007) that are sued under Section 11 of the 1933 Securities Act within 3 years of their IPO and an industry-size-year matched sample of 81 control firms. We have assembled a novel, hand-collected data set that measures the lawsuit, corporate governance, and firm characteristics of these 162 firms. We report a significant positive association between the likelihood of securities fraud allegations and CEO equity incentives, which is consistent with the idea that there is a "dark side" to executive equity incentives. This association is robust to alternative model specifications, sample selection criteria, and estimation methods. In addition, we find that the risk of being sued is higher for firms whose board is dominated by insiders, whose CEOs are older, have a shorter tenure, or who founded the firm

Mathematical model of vacuum freeze-drying in the secondary drying

The freeze-drying process is a complex heat and mass transfer process virtually. The drying process of freeze-drying is not only the key stage which decides the success of freeze-drying, but also the most difficult stage to control. There are lots of papers about heat and mass transfer in vacuum freeze drying at home and abroad. The present status of research on heat and mass transfer during vacuum freeze drying in the secondary drying is summed up and analyzed, and the trend of research in this field is discussed in this paper

Analysis of heat and mass transfer mechanism of vacuum freeze-drying in the primary drying

The freeze-drying process is a complex heat and mass transfer process virtually. The drying process of freeze-drying is not only the key stage which decides the success of freeze-drying, but also the most difficult stage to control. There are lots of papers about heat and mass transfer in vacuum freeze drying at home and abroad. The present status of research on heat and mass transfer during vacuum freeze drying in the primary drying is summed up and analyzed, the trend of research in this field is discussed in this paper

Clinical characteristics and long term post-operative outcome of cardiac myxoma

Background and aim: Myxoma is the most common type of primary cardiac neoplasm, but the clinical characteristics and long term outcome are less known in the elderly in China. Methods: We analyzed medical records of 112 consecutive patients who underwent operative resection of cardiac myxoma between December 1988 and December 2010 in our hospital. Their data were retrospectively analyzed and the difference between two age groups (< 60 years, n = 87 and ≥ 60 years, n = 25) was compared. Results: The mean age of 112 patients was 48.8 ± 12.5 (range 13 ~ 75) years, and 66 patients (58.9 %) were female. The interval from onset of symptoms to diagnosis was 12 months and the most common presenting symptoms were chest distress (66 patients 58.9 %), followed by palpitations (55 patients, 49.1 %) and dyspnea (47 patients, 42.0 %). Mitral valve diastolic murmur was heard in 67 (59.1 %) patients. The tumor was located in the left atrium in 96 (85.8 %) patients. There were no in-hospital death. During follow-up ranged between one and twenty-one (7.3 ± 5.3) years, there was no malignancy. Myxoma recurred in 3 (2.7 %) patients and deaths occurred in 5 (4.5 %) patients. The 5 and 15 years survival was 97.8 % and 89.5 %, respectively. To compare with the younger patients, the elderly have higher ratios of concomitant hypertension, fewer complaints of dyspnea and chest distress (p < 0.05). Conclusion: The elderly have lower complaints of dyspnea and chest distress, surgical treatment is associated with low long-term mortality and recurrence rate even in the elder patients

Electrochemical Reducation of TiO2/Al2O3/C to Ti3AlC2 and Its Derived Two-Dimensional (2D) Carbides

Ti3AlC2 has been directly synthesized from TiO2/Al2O3/C mixture precursors (3TiO2/0.5Al2O3/1.5C and 2TiO2/0.5Al2O3/C) by a molten salt electrolysis process at 900?C and 3.2 V in molten CaCl2. The influence of initial carbon content on the electrosynthesized products has been investigated. The result shows that the main phase of the electrosynthesized products changes from Ti3AlC to Ti2AlC and then to Ti3AlC2 with the increasing carbon content, and the electrosynthesized Ti3AlC2 is carbon deficient. The morphology observation shows that the electrosynthesized Ti3AlC2 particles possess smooth surfaces and dense flake-like microstructure. The reaction mechanism of the electroreduction of TiO2/Al2O3/C mixture precursor has been discussed based on the time- and position-dependent phase constitution analysis. In addition, two-dimensional (2D) Ti3AlC2-derived carbides, i.e., Ti3C2Tx and TiCx have been successfully prepared from the electrosynthesized Ti3AlC2 by a chemical etching process and an electrochemical etching process, respectively. Both derived carbides exhibit the similar layered structure, in which single layer carbides are composed of plentiful nanometer carbides. It is suggested that the molten salt electrolysis process has a great potential to be used for the facile synthesis of Mn+1AXn phases (such as Ti3AlC2) from their oxides precursors, and the synthesized Mn+1AXn phases can be further converted into 2D carbidesauthorsversionPeer reviewe