Optimal sequencing of a set of positive numbers with the variance of the sequence's partial sums maximized

We consider the problem of sequencing a set of positive numbers. We try to find the optimal sequence to maximize the variance of its partial sums. The optimal sequence is shown to have a beautiful structure. It is interesting to note that the symmetric problem which aims at minimizing the variance of the same partial sums is proved to be NP-complete in the literature.Comment: 12 pages;Accepted for publication in Optimization Lette

Universal critical properties of the Eulerian bond-cubic model

We investigate the Eulerian bond-cubic model on the square lattice by means of Monte Carlo simulations, using an efficient cluster algorithm and a finite-size scaling analysis. The critical points and four critical exponents of the model are determined for several values of $n$. Two of the exponents are fractal dimensions, which are obtained numerically for the first time. Our results are consistent with the Coulomb gas predictions for the critical O($n$) branch for $n < 2$ and the results obtained by previous transfer matrix calculations. For $n=2$, we find that the thermal exponent, the magnetic exponent and the fractal dimension of the largest critical Eulerian bond component are different from those of the critical O(2) loop model. These results confirm that the cubic anisotropy is marginal at $n=2$ but irrelevant for $n<2$

Spousal concordance in adverse childhood experiences and the association with depressive symptoms in middle-aged and older adults: findings across China, the US, and Europe

Copyright \ua9 2023 Sun, Ren, Zhu, Cheng, Liu, Li, Xia, Yuan, Adeloye, Rudan, Canoy, Song, on behalf of the Global Health Epidemiology Research Group (GHERG). Background: Adverse childhood experiences (ACEs) are associated with higher depressive risks in adulthood. Whether respondents’ ACEs are associated with their own depressive symptoms in adulthood and whether this association extends to their spouses’ depressive symptoms remain unexplored. Methods: Data were from China Health and Retirement Longitudinal Study (CHARLS), the Health and Retirement Study (HRS), and the Survey of Health, Ageing and Retirement in Europe (SHARE). ACEs were categorized into overall, intra-familial, and extra-familial ACEs. Correlations of couples’ ACEs were calculated using Cramer’s V and partial Spearman’s correlation. Associations of respondents’ ACEs with spousal depressive symptoms were assessed using logistic regression, and mediation analyses were conducted to explore the mediating role of respondents’ depressive symptoms. Results: Significant associations between husbands’ ACEs and wives’ depressive symptoms, with odds ratios (ORs) and 95% confidence intervals (CIs) of 2.09 (1.36–3.22) for 4 or more ACEs in CHARLS, and 1.25 (1.06–1.48) and 1.38 (1.06–1.79) for 2 or more ACEs in HRS and SHARE. However, wives’ ACEs were associated with husbands’ depressive symptoms only in CHARLS and SHARE. Findings in intra-familial and extra-familial ACEs were consistent with our main results. Additionally, respondents’ depressive symptoms mediated more than 20% of the effect of respondents’ ACEs on spousal depressive symptoms. Conclusion: We found that ACEs were significantly correlated between couples. Respondents’ ACEs were associated with spousal depressive symptoms, with respondents’ depressive symptoms mediating the association. The bidirectional implications of ACEs on depressive symptoms should be considered within household and effective interventions are warranted

Study of the radiation damage caused by ion implantation in ZnO and its relation to magnetism

Defects play an important role in causing room temperature ferromagnetism in ZnO films. Multi-energy ion implantation has been employed to introduce different concentrations of non-magnetic ions, including argon, arsenic and krypton, into high-quality ZnO films and room temperature ferromagnetism has been observed for As and Kr implanted ZnO while none was observed for Ar doped films. The Monte Carlo simulation code SRIM was adopted to simulate the distributions of the implanted ions, the induced zinc and oxygen vacancies and the resulting interstitials. A common radiation damage parameter, known as the atomic displacements per atom (dpa), was calculated to quantify the primary radiation damage production. Our results show that the observed magnetic moment measured at low temperatures due to implantation with a given ion is proportional to the dpa. The constant of proportionality between the magnetism and the dpa depends on the implanted ion. This constant is largest for heavy, large ions. To obtain room temperature d0 magnetism in ZnO, non-magnetic ions with high mass are suggested to be implanted into ZnO films

Implications of a W^+W^- (ZZ) - Higgs - t c-bar$ Interaction for e^+e^- -> t c-bar \nu_e \nu_e-bar, t c-bar e^+ e^-, t c-bar Z and for t -> cW^+W^-, cZZ in a Two Higgs Doublet Model

The Standard Model with one extra Higgs doublet may give rise to enhanced TREE-LEVEL flavor-changing-scalar coupling of a neutral Higgs to a pair of top-charm quarks. This coupling may drive a large TREE-LEVEL effective W^+W^-(ZZ) - Higgs - t c-bar interaction. As a result we find that the reactions e^+e^- -> t c-bar \nu_e \nu_e-bar, t c-bar e^+ e^-, t c-bar Z and the two rare top decays t -> cW^+W^-, t -> cZZ become very sensitive probes of such an effective interaction. The most promising ones, e^+e^- -> t c-bar \nu_e \nu_e-bar, t c-bar e^+ e^-, may yield several hundreds and up to thousands of such events at the Next Linear Collider with a center of mass energy of \sqrt{s}=0.5 - 2 TeV if the mass of the lightest neutral Higgs is a few hundred GeV. The rare decays t -> cW^+W^- and t -> cZZ may be accessible at the LHC if the mass of the lightest neutral Higgs lies in the narrow window 150 GeV < m_h < 200 GeV.Comment: 18 pages, plain latex, 12 figures embadded in the text using epsfi

Observation of An Evolving Magnetic Flux Rope Prior To and During A Solar Eruption

Explosive energy release is a common phenomenon occurring in magnetized plasma systems ranging from laboratories, Earth's magnetosphere, the solar corona and astrophysical environments. Its physical explanation is usually attributed to magnetic reconnection in a thin current sheet. Here we report the important role of magnetic flux rope structure, a volumetric current channel, in producing explosive events. The flux rope is observed as a hot channel prior to and during a solar eruption from the Atmospheric Imaging Assembly (AIA) telescope on board the Solar Dynamic Observatory (SDO). It initially appears as a twisted and writhed sigmoidal structure with a temperature as high as 10 MK and then transforms toward a semi-circular shape during a slow rise phase, which is followed by fast acceleration and onset of a flare. The observations suggest that the instability of the magnetic flux rope trigger the eruption, thus making a major addition to the traditional magnetic-reconnection paradigm.Comment: 13 pages, 3 figure