2,419 research outputs found
Coupling motion of colloidal particles in quasi-twodimensional confinement
The Brownian motion of colloidal particles in quasi-two-dimensional (q2D)
confinement displays a distinct kinetic character from that in bulk. Here we
experimentally report dynamic coupling motion of Brownian particles in a
relatively long process (∼100 h), which displays a quasi-equilibrium state in the
q2D system. In the quasi-equilibrium state, the q2D confinement results in the
coupling of particle motions, which slowly damps the motion and interaction of
particles until the final equilibrium state is reached. The process of approaching
the equilibrium is a random relaxation of a many-body interaction system of
Brownian particles. As the relaxation proceeds for ∼100 h, the system reaches
the equilibrium state in which the energy gained by the particles from the
stochastic collision in the whole system is counteracted by the dissipative energy
resulting from the collision. The relaxation time of this stochastic q2D system is
17.7 h. The theory is developed to explain coupling motions of Brownian particles
in q2D confinement
Evaluation of a comprehensive intervention with a behavioural modification strategy for childhood obesity prevention: a nonrandomized cluster controlled trial
Background: With regard to the global childhood obesity epidemic, it is imperative that effective lifestyle interventions are devised to combat childhood obesity. This paper describes the development and implementation of a comprehensive (a combination of diet and physical activity (PA)), social cognitive behaviour modification intervention using accelerometry and a dietary diary to tackle child overweight and obesity. The comprehensive intervention effect was evaluated in a comparison with diet only, PA only and a no-treatment control group. Methods: A pilot study was conducted with a non-randomized cluster design. Four hundred thirty-eight overweight and obese children aged 7-12 years from ten primary schools in Beijing were recruited to receive a one-year intervention. Participants were allocated into one of four groups: the comprehensive intervention group; the PA only group (Happy 10 program); the diet only group (nutrition education program); and a control group. The effects of intervention on adiposity, blood pressure, and biochemical indicators were assessed by examining 2-way interactions (time x intervention) in linear mixed models. Means and 95 % confidence intervals (CI) for the adjusted changes between post-intervention and baseline relative to changes in the control group were calculated and reported as effect sizes. Results: The percentage of body fat in the comprehensive intervention group showed a significant relative decrease (adjusted change: -1.01 %, 95 % CI: (-1.81, -0.20) %) compared with the PA only, diet only or control groups (P < 0.001). Systolic blood pressure significantly decreased in the comprehensive intervention group (adjusted change: -4.37 mmHg, 95 % CI: (-8.42, -0.33) mmHg), as did diastolic blood pressure (adjusted change: -5.50 mmHg, 95 % CI (-8.81, -2.19) mmHg) (P < 0.05). Compared with the other two intervention groups and the control group, positive adjusted changes in fasting glucose in the comprehensive group were found, although not for the biochemical lipid metabolism indicators. Positive but non-significant adjusted changes in body mass index and waist circumference were observed. Conclusions: Compared with the diet or PA only intervention groups, the current comprehensive program had superior positive effects on body fat percentage and blood pressure but not on the biochemical lipid metabolism indicators in Chinese overweight and obese children. Future randomized controlled trials and long-term follow-up studies are required to elaborate the findings of the current intervention.Danone Dietary and Nutrition Research and Education Grant [DIC2009-11]; National Science and Technology Support Important Projects for the "Eleven Five-Year Plan" of China [2008BAI58B05]; Natural Science Foundation of China (NSFC) [81172683]SCI(E)[email protected]; [email protected]
N′-(2-Hydroxy-4-methoxybenzylidene)-4-methylbenzohydrazide
The asymmetric unit of the title compound, C16H16N2O3, contains four independent molecules with different conformations; the dihedral angles between the two benzene rings in the molecules are 39.7 (3), 45.4 (3), 50.6 (3) and 51.6 (3)°. Intramolecular O—H⋯N hydrogen bonds are observed in the molecule. In the crystal, N—H⋯O hydrogen bonds link the molecules into two crystallographically independent chains propagating in [010], and each chain is formed by two alternating independent molecules. Weak C—H⋯O interactions also occur
Decorrelation of Neutral Vector Variables: Theory and Applications
In this paper, we propose novel strategies for neutral vector variable
decorrelation. Two fundamental invertible transformations, namely serial
nonlinear transformation and parallel nonlinear transformation, are proposed to
carry out the decorrelation. For a neutral vector variable, which is not
multivariate Gaussian distributed, the conventional principal component
analysis (PCA) cannot yield mutually independent scalar variables. With the two
proposed transformations, a highly negatively correlated neutral vector can be
transformed to a set of mutually independent scalar variables with the same
degrees of freedom. We also evaluate the decorrelation performances for the
vectors generated from a single Dirichlet distribution and a mixture of
Dirichlet distributions. The mutual independence is verified with the distance
correlation measurement. The advantages of the proposed decorrelation
strategies are intensively studied and demonstrated with synthesized data and
practical application evaluations
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