Entanglement in a Time-Dependent Coupled XY Spin Chain in an External Magnetic Field

We consider an infinite one dimensional anisotropic XY spin chain with a nearest neighbor time-dependent Heisenberg coupling J(t) between the spins in presence of a time-dependent magnetic field h(t). We discuss a general solution for the system and present an exact solution for particular choice of J and h of practical interest. We investigate the dynamics of entanglement for different degrees of anisotropy of the system and at both zero and finite temperatures. We find that the time evolution of entanglement in the system show non-ergodic and critical behavior at zero and finite temperatures and different degrees of anisotropy. The asymptotic behavior of entanglement at the infinite time limit at zero temperature and constant J and h depends only the parameter lambda=J/h rather than the individual values of J and h for all degrees of anisotropy but changes for nonzero temperature. Furthermore, the asymptotic behavior is very sensitive to the initial values of J and h and for particular choices we may create finite asymptotic entanglement regardless of the final values of J and h. The persistence of quantum effects in the system as it evolves and as the temperature is raised is studied by monitoring the entanglement. We find that the quantum effects dominates within certain regions of the kT-lambda space that vary significantly depending on the degree of the anisotropy of the system. Particularly, the quantum effects in the Ising model case persists in the vicinity of both its critical phase transition point and zero temperature as it evolves in time. Moreover, the interplay between the different system parameters to tune and control the entanglement evolution is explored.Comment: 33 pages, 17 figures; v3: Grammar errors and typos corrected, Figure 17(b) update

Entanglement dynamics of one-dimensional driven spin systems in time-varying magnetic fields

We study the dynamics of entanglement for a one-dimensional spin chain with a nearest neighbor time dependent Heisenberg coupling J(t) between the spins in presence of a time dependent external magnetic field h(t) at zero and finite temperatures. We consider different forms of time dependence for the coupling and magnetic field; exponential, hyperbolic and periodic. We examined the system size effect on the entanglement asymptotic value. It was found that for a small system size the entanglement starts to fluctuate within a short period of time after applying the time dependent coupling. The period of time increases as the system size increases and disappears completely as the size goes to infinity. We also found that when J(t) is periodic the entanglement shows a periodic behavior with the same period, which disappears upon applying periodic magnetic field with the same frequency. Solving the particular case where J(t) and h(t) are proportional exactly, we showed that the asymptotic value of entanglement depends only on the initial conditions regardless of the form of J(t) and h(t) applied at t > 0.Comment: 22 pages and 8 figure

An Evaluation of the Effectiveness of a Simulated Classroom-based Intervention on Concussion Rehabilitation Among Individuals with Persistent Post-Concussion Symptoms

Although recent clinical and scientific effort has focused on the development of guidelines for post-concussion return to play/work/learn, there is still relatively little literature that addresses specific treatment methods by which this can be accomplished. Accordingly, this study investigated the effect of a 7-week simulated classroom-based intervention on the self-reporting of symptom scores among 71 individuals with persistent concussion symptoms (26 men and 45 women). All participants were provided with novel strategies for reading, writing, study skills, social communication and technology use. Self-assessment of symptoms were obtained weekly, both before and after each session of the treatment program, in an effort to monitor the cognitive demands of each session, and to identify the extent to which the program produced an improvement over the course of seven weeks. Results suggested that concussion symptoms were exacerbated in the short term by treatment, F(1, 343) = 255.69, p \u3c .05, consistently across the 7 weeks of the program. An overall downward trend was, however, observed for symptom scores, over the seven weeks of the treatment program, and a statistically significant difference was noted between the first and last week of the program, F(6, 343) = 2.29, p \u3c .05. Post-hoc analysis of means (using Tukey’s HSD) suggests that there was a significant improvement (alpha = 0.05) of self-reported symptoms when comparing weeks 1 and 6, and between weeks 1 and 7. These results suggest that, transient exacerbation of symptoms aside; the targeted simulated classroom interventions produced a statistically significant benefit in the management of persistent concussion symptoms within this particular return-to-learn protocol

Measurement quench in many-body systems

Measurement is one of the key concepts which discriminates classical and quantum physics. Unlike classical systems, a measurement on a quantum system typically alters it drastically as a result of wave function collapse. Here we suggest that this feature can be exploited for inducing quench dynamics in a many-body system while leaving its Hamiltonian unchanged. Importantly, by doing away with dedicated macroscopic devices for inducing a quench -- using instead the indispensable measurement apparatus only -- the protocol is expected to be easier to implement and more resilient against decoherence. By way of various case studies, we show that our scheme also has decisive advantages beyond reducing decoherence -- for spectroscopy purposes and probing nonequilibrium scaling of critical and quantum impurity many-body systems.Comment: 6 pages, 5 figure

Object-Based Coastal Morphological Change Analysis Based on LiDAR and Hurricane Events

Storms are considered one of the rapid climatic events that have a dramatic impact on coastal morphology, hence they require further investigation and quantifying of coastal changes and responses. Light detection and ranging (LiDAR) is the most advanced technology to be widely used by researchers for coastal geomorphological studies. The purpose of this study is to apply an object-based approach using repeated LiDAR surveys to understand the short-term morphological changes that occurred on Santa Rosa Island, Florida after category 3 hurricanes Ivan (2004) and Dennis (2005), making it the first study to apply this method, as opposed to previous studies’ commonly used field-based approaches. The first analysis was conducted using a coastal morphology analysis (CMA) tool. In the second analysis, the extracted mean elevation change values were linked to three factors—mean vegetation, mean slope, and mean elevation—to demonstrate their contribution to the change using ordinary least square (OLS) analysis. The third analysis was carried out using the classification and regression tree (CART) analysis. Of the study area, 18.64% encountered erosional processes and 11.35% with depositional processes during Hurricane Ivan, whereas during Hurricane Dennis, 5.91% faced erosional processes and 8.18% was affected by depositional processes. Both hurricanes resulted in a net sediment loss; 283,167 m3 during Hurricane Ivan and 52,440 m3 during Hurricane Dennis. Generally, objects tended to be irregular, asymmetrical, and shaped with smooth boundaries. Along the coast, most objects tended to have an elongated shape, but inland the shapes were more irregular. The overall OLS model during Hurricane Ivan yielded statistically significant results for the three factors, with a confidence level of 0.00 and an adjusted r-square of 0.40; and during Hurricane Dennis, the mean vegetation and mean elevation results yielded significant statistical results (p-value 0.00), while slope did not show significance and had an adjusted r-square of 0.47. CART analysis of both hurricanes ranked the mean elevation as the most important factor in predicting the mean elevation change, followed by the mean slope and finally the mean vegetation variable

Exploring Pre-Service Special and General Education Teachers’ Beliefs and Attitudes in Mathematics and Learning and Teaching Mathematics

The purpose of this quantitative study was to examine and compare the beliefs and attitudes of pre-service special and general education teacher candidates regarding mathematics and the learning and teaching of mathematics and explore factors including student learning, teaching math, math rated affect (math anxiety and confidence), effectance motivation, usefulness of math, and the effect of previous teachers’ perceptions. The interrelationship among these factors was explored and compared to participants’ academic level and majors (i.e., special education and general) to determine whether these factors influenced the approaches pre-service teachers thought they would use when teaching math. The participants were 362 special and general pre-service teachers (elementary education and secondary math education) at all four academic levels (freshman, sophomore, junior, and senior). Statistical analysis methods employed to obtain the results included multivariate analysis of variance, chi square, and multiple linear regression. Findings revealed statistically significantly differences in beliefs and attitudes toward mathematics among pre-service teachers across their academic majors. In comparison to the other two participant groups, special education pre-service teachers had more anxiety and less confidence in their math abilities and had the lowest mean scores in usefulness of math, effectance motivation, teacher perception, and student learning of all three participant groups. Findings also indicated the relationships between major and planning to teach math and major and desire to teach math were both statistically significant. In this study, special education pre-service teachers were less likely to plan or want to teach math when compared to elementary and secondary math pre-service teachers. Furthermore, findings suggested math rated affect and teacher perception could predict pre-service teachers’ beliefs in student learning. Findings suggested pre-service teachers who had less math anxiety and were more confident in their math ability were more likely to believe in a constructivist approach in student learning. Finally, a significant relationship was found between pre-service teachers’ beliefs in teaching math and effectance motivation, which implied pre-service teachers who had more interest and motivation toward math were more likely to believe teaching math involved constructivist practices. Implications and suggestions for future research were provided based on the results of the current study

H2S donor GYY4137 ameliorates paclitaxel-induced neuropathic pain in mice

Paclitaxel-induced neuropathic pain (PINP) is a dose-limiting side effect that largely affects the patient’s quality of life and may limit the use of the drug as a chemotherapeutic agent for treating metastatic breast cancer and other solid tumors. Recently, a putative role for the gaseous mediator hydrogen sulfide (H2S) in nociception modulation has been suggested. The aim of the present study was to investigate the potential efficacy of the slow release H2S donor GYY4137 to alleviate and prevent PINP. Female BALB/c mice that were intraperitoneally (i.p.) injected with paclitaxel (2 mg/kg) for 5 consecutive days developed thermal hyperalgesia, cold and mechanical allodynia and had reduced of H2S, generation in the spinal cord and paw skin. Treatment of mice with established thermal hyperalgesia with GYY4137 or the analgesic positive control drug gabapentin produced antihyperalgesic activities. The antihyperalgesic activity of GYY4137 was antagonized by the ATP sensitive potassium channels (KATP channels) blocker glibenclamide. Co-treatment with GYY4137 and paclitaxel prevented the paclitaxel-induced decrease in H2S, generation as well as the paclitaxel-induced thermal hyperalgesia, cold allodynia and mechanical allodynia. GYY4137 enhanced paclitaxel\u27s anti-proliferative effects against the breast cancer cell line MCF-7. The present results suggest that GYY4137 alleviates paclitaxel-induced thermal hyperalgesia, via KATP channels. GYY4137 prevents PINP possibly by blocking the paclitaxel-induced reduction in the generation of H2S, in the tissues, while enhancing the anti-cancer activity of paclitaxel, and therefore warrants further research as a candidate for prevention of PINP in clinical settings

Characterizing the effect of retractions on scientific careers

Retracting academic papers is a fundamental tool of quality control when the validity of papers or the integrity of authors is questioned post-publication. While retractions do not eliminate papers from the record, they have far-reaching consequences for retracted authors and their careers, serving as a visible and permanent signal of potential transgressions. Previous studies have highlighted the adverse effects of retractions on citation counts and coauthors' citations; however, the broader impacts beyond these have not been fully explored. We address this gap leveraging Retraction Watch, the most extensive data set on retractions and link it to Microsoft Academic Graph, a comprehensive data set of scientific publications and their citation networks, and Altmetric that monitors online attention to scientific output. Our investigation focuses on: 1) the likelihood of authors exiting scientific publishing following a retraction, and 2) the evolution of collaboration networks among authors who continue publishing after a retraction. Our empirical analysis reveals that retracted authors, particularly those with less experience, tend to leave scientific publishing in the aftermath of retraction, particularly if their retractions attract widespread attention. We also uncover that retracted authors who remain active in publishing maintain and establish more collaborations compared to their similar non-retracted counterparts. Nevertheless, retracted authors with less than a decade of publishing experience retain less senior, less productive and less impactful coauthors, and gain less senior coauthors post-retraction. Taken together, notwithstanding the indispensable role of retractions in upholding the integrity of the academic community, our findings shed light on the disproportionate impact that retractions impose on early-career authors.Comment: 49 pages, 13 figures, 19 table