Urban–rural disparity in blood pressure among Chinese children: 1985–2010

Background: Understanding the urban-rural gap in childhood blood pressure (BP) is crucial to alleviate the urban-rural disparity in burden of hypertension in the future. This study investigated trends in urban-rural BP disparity and the influence of body mass index among Chinese children between 1985 and 2010. Methods: Data included 1 010 153 children aged 8-17 years enrolled in the Chinese National Survey on Students' Constitution and Health, a successive national cross-sectional survey. High BP was defined according to age-sex- and height-specific 95th percentile. Multi-variable linear and logistic regression models were used to assess the urban-rural BP differentials. Results: Although urban children had greater prevalence of overweight and obesity than rural counterparts, rural children revealed higher levels of BP across the consecutive 25-year periods. The urban-rural disparity in prevalence of high systolic BP decreased from 2.3 (95% confidence interval: 2.3, 2.6) % to 0.2 (-0.1, 0.4) % in boys and 3.7 (3.5, 4.0) % to 0.6 (0.3, 0.8) % in girls between 1985 and 2010 after adjusting for confounding factors. Further adjustment of body mass index did not change the urban-rural disparity and its trend. The similar results were also observed for diastolic BP. Conclusions: Despite the urban-rural disparity in BP decreased between 1985 and 2010, rural children constantly showed higher BP levels than their urban counterparts. Since these differentials in BP cannot be explained by obesity, study of other potential factors could provide further opportunity to bridge this gap

Onset of unsteady horizontal convection in rectangle tank at Pr=1Pr=1

The horizontal convection within a rectangle tank is numerically simulated. The flow is found to be unsteady at high Rayleigh numbers. There is a Hopf bifurcation of $Ra$ from steady solutions to periodic solutions, and the critical Rayleigh number $Ra_c$ is obtained as $Ra_c=5.5377\times 10^8$ for the middle plume forcing at $Pr=1$, which is much larger than the formerly obtained value. Besides, the unstable perturbations are always generated from the central jet, which implies that the onset of instability is due to velocity shear (shear instability) other than thermally dynamics (thermal instability). Finally, Paparella and Young's [J. Fluid Mech. 466 (2002) 205] first hypotheses about the destabilization of the flow is numerically proved, i.e. the middle plume forcing can lead to a destabilization of the flow.Comment: 4pages, 6 figures, extension of Chin. Phys. Lett. 2008, 25(6), in pres

Improved PSO algorithm based on chaos theory and its application to design flood hydrograph

AbstractThe deficiencies of basic particle swarm optimization (bPSO) are its ubiquitous prematurity and its inability to seek the global optimal solution when optimizing complex high-dimensional functions. To overcome such deficiencies, the chaos-PSO (COSPSO) algorithm was established by introducing the chaos optimization mechanism and a global particle stagnation-disturbance strategy into bPSO. In the improved algorithm, chaotic movement was adopted for the particles' initial movement trajectories to replace the former stochastic movement, and the chaos factor was used to guide the particles' path. When the global particles were stagnant, the disturbance strategy was used to keep the particles in motion. Five benchmark optimizations were introduced to test COSPSO, and they proved that COSPSO can remarkably improve efficiency in optimizing complex functions. Finally, a case study of COSPSO in calculating design flood hydrographs demonstrated the applicability of the improved algorithm

Group Based Interference Alignment

In the $K$-user single-input single-output (SISO) frequency-selective fading interference channel, it is shown that the maximal achievable multiplexing gain is almost surely $K/2$ by using interference alignment (IA). However, when the signaling dimensions are limited, allocating all the resources to all users simultaneously is not optimal. So, a group based interference alignment (GIA) scheme is proposed, and it is formulated as an unbounded knapsack problem. Optimal and greedy search algorithms are proposed to obtain group patterns. Analysis and numerical results show that the GIA scheme can obtain a higher multiplexing gain when the resources are limited.Comment: 3 pages, 3 figures. resubmitted to IEEE Communications Letter

2-Bromo-4-chloro-6-(cyclo­hexyl­imino­meth­yl)phenol

The title compound, C13H15BrClNO, was prepared by the condensation of equimolar quanti­ties of 3-bromo-5-chloro­salicyl­aldehyde with cyclo­hexyl­amine in methanol. There is an intra­molecular O—H⋯N hydrogen bond in the mol­ecule. The cyclo­hexyl ring adopts a chair conformation

6-Allyl-3-(6-chloro-3-pyridylmeth­yl)-6,7-dihydro-3H-1,2,3-triazolo[4,5-d]pyrimidin-7-imine

The title compound, C13H12ClN7, crystallizes with two independent mol­ecules in the asymmetric unit, each with similar geometries. The dihedral angles between the triazole and pyrimidine rings are 0.45 (9) and 1.00 (10)° in the two mol­ecules. A number of N—H⋯N hydrogen bonds co-operate with C–H⋯N contacts, forming a supra­molecular array in the ab plane. C—H⋯π inter­actions are also present. One of the vinyl groups was found to be disordered so that the C(H)=CH2 atoms were resolved over two positions with the major component having a site occupancy factor of 0.539 (4)