Entanglement and spin squeezing properties for three bosons in two modes

We discuss the canonical form for a pure state of three identical bosons in two modes, and classify its entanglement correlation into two types, the analogous GHZ and the W types as well known in a system of three distinguishable qubits. We have performed a detailed study of two important entanglement measures for such a system, the concurrence $\mathcal{C}$ and the triple entanglement measure $\tau$. We have also calculated explicitly the spin squeezing parameter $\xi$ and the result shows that the W state is the most ``anti-squeezing'' state, for which the spin squeezing parameter cannot be regarded as an entanglement measure.Comment: 7 pages, 6 figures; corrected figure sequence. Thanks to Dr. Han P

Classical Poisson structures and r-matrices from constrained flows

We construct the classical Poisson structure and $r$-matrix for some finite dimensional integrable Hamiltonian systems obtained by constraining the flows of soliton equations in a certain way. This approach allows one to produce new kinds of classical, dynamical Yang-Baxter structures. To illustrate the method we present the $r$-matrices associated with the constrained flows of the Kaup-Newell, KdV, AKNS, WKI and TG hierarchies, all generated by a 2-dimensional eigenvalue problem. Some of the obtained $r$-matrices depend only on the spectral parameters, but others depend also on the dynamical variables. For consistency they have to obey a classical Yang-Baxter-type equation, possibly with dynamical extra terms.Comment: 16 pages in LaTe

The Impact of Geopolitical Risks on Tourism Supply in Developing Economies: The Moderating Role of Social Globalization

Capital investment is vital for sustainable tourism growth, particularly in times of geopolitical turmoil. This study examines how tourism investment was influenced by geopolitical risks considering social globalization as a moderating factor. Data were collected from 18 developing economies between 1995 and 2018. The results from the fixed effects and the least squares dummy variable–corrected methods show that the geopolitical risks negatively affect capital investment in tourism, with social globalization playing a moderating role in alleviating the adverse effect. The results were robust to different measures and analyses. The study advances our understanding of sustainable tourism growth amid geopolitical turmoil. Policymakers, especially those from developing economies, are suggested to be vigilant about the media atmosphere of geopolitics and enhancing social globalization as a countermeasure against politically turbulent times. The study also provides implications for alleviating the impact of the global pandemic on tourism investment

Study on the insecticidal activity compounds of the essential oil from Syzygium aromaticum against stored grain insect pests

Insect pests are a major cause of damage in stored grain around the world. To control the stored grain insects, synthetic insecticides have been used extensively for many years, resulting in insect populations that are resistant to insecticides. Consequently there is an interest to find alternatives to chemical pesticides. The essential oil from Syzygium aromaticum (clove oil) has a number of bioactive compounds. The chemical constituents of the clove oil were analyzed by GC-MS, and 9 of 18 compounds were identified. The main compound (83%) was 2-methoxy-4-(2-propenyl)-phenol the second most common compound (12%) was trans-caryophyllene. These two pure compounds and clove oil were tested for toxicity and repellency against Rhyzopertha dominica, Sitophilus oryzae and Tribolium castaneum. The pure compounds were tested at the dosages found in clove oil. The mortality from 2-methoxy-4-(2-propenyl)-phenol was not significantly different from clove oil, suggesting that the activity of clove oil was solely due to this major compound. The repellency results were more complex. 2-methoxy-4-(2-propenyl)-phenol was more repellant than clove oil. Trans-caryophyllene was less toxic and less repellant than both clove oil and 2-methoxy-4-(2-propenyl)- phenol. The potential for these compounds to be used to control stored product insects is discussed. Keywords: Essential oils, Syzygium aromaticum, Clove oil, Insecticidal activity compounds, Stored grain insect

Effects of AdR-siPTEN on learning capability, memory and extracellular signal-regulated kinase expression in hippocampus of rats with vascular dementia

This study investigated the effects of a recombinant adenovirus, AdR-siPTEN, on learning capability, memory and extracellular signal-regulated kinase (ERK) expression in the hippocampus of rats withvascular dementia (VD). VD was introduced via permanent bilateral common carotid artery ligation (2-VO) in rats. AdR-siPTEN recombinant adenovirus and unrelated control adenovirus AdRFP were independently injected into the hippocampus of VD rats. Four weeks later, Morris water maze test was performed to detect the cognition of rats. Hematoxylin and eosin (HE) and Nissl staining were used to observe cellular morphous and neuronal damage in the hippocampus CA1 region. The mRNA andprotein expression of a phosphatase and tensin homolog deleted on chromosome 10 (PTEN), phosphatidylinositol 3-kinase (PI3K), ERK and cAMP response element-binding (CREB) were detected by reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively. PTEN expression was reduced apparently in hippocampus after RNAi intervation in the AdR-siPTENgroup (P<0.05). Compared with the AdRFP group, rats in the AdR-siPTEN group had significantly shorter escape latency to the invisible platform (except on the first day of test) (P<0.05); and more neurons with regular shape and/or Nissl bodies in hippocampus were observed in the AdR-siPTEN group, suggesting attenuated neuronal damage and degeneration. Additionally, the expression of PI3K, ERK and CREB in hippocampus CA1 region of AdR-siPTEN treatment group was markedly higher than that in the AdRFP group (P < 0.05). However, compared with the normal group, the expression of PI3K, ERK and CREB was dramatically decreased in the AdRFP group (P < 0.05). AdR-siPTEN may improvethe cognition of VD rats, attenuate neuronal damage and promote expression of ERK and CREB, leading to the protective effects on neuronal synaptic plasticity in VD rats. These results suggest that PTEN down-regulation may exert potential therapeutic effects on VD

Stochastic Fractal Based Multiobjective Fruit Fly Optimization

The fruit fly optimization algorithm (FOA) is a global optimization algorithm inspired by the foraging behavior of a fruit fly swarm. In this study, a novel stochastic fractal model based fruit fly optimization algorithm is proposed for multiobjective optimization. A food source generating method based on a stochastic fractal with an adaptive parameter updating strategy is introduced to improve the convergence performance of the fruit fly optimization algorithm. To deal with multiobjective optimization problems, the Pareto domination concept is integrated into the selection process of fruit fly optimization and a novel multiobjective fruit fly optimization algorithm is then developed. Similarly to most of other multiobjective evolutionary algorithms (MOEAs), an external elitist archive is utilized to preserve the nondominated solutions found so far during the evolution, and a normalized nearest neighbor distance based density estimation strategy is adopted to keep the diversity of the external elitist archive. Eighteen benchmarks are used to test the performance of the stochastic fractal based multiobjective fruit fly optimization algorithm (SFMOFOA). Numerical results show that the SFMOFOA is able to well converge to the Pareto fronts of the test benchmarks with good distributions. Compared with four state-of-the-art methods, namely, the non-dominated sorting generic algorithm (NSGA-II), the strength Pareto evolutionary algorithm (SPEA2), multi-objective particle swarm optimization (MOPSO), and multiobjective self-adaptive differential evolution (MOSADE), the proposed SFMOFOA has better or competitive multiobjective optimization performance