In this study, we describe changes of plasma levels of the hypothalamic neuropeptide orexin A in obese children during the reduction of body weight and its relationship to other biochemical and anthropometrical parameters. We measured orexin A fasting plasma levels by the RIA method in 58 obese children - 33 girls and 25 boys; mean age 13.1±0.38 years (range 7-18.5) before and after 5 weeks of weight-reduction therapy. Leptin, IGF-1, and IGFBP-3 levels were measured in all the subjects and were compared to orexin A levels and anthropometrical data. Average weight in subjects before weight-reduction was 74.2±2.79 kg and after weight-loss 67.4±2.60 kg (p<0.0001). Orexin A levels before the therapy were 33.3±1.97 pg/ml and after the therapy 51.7±3.07 pg/ml (p<0.0001). Levels of orexin A were not significantly different between girls and boys (p=0.7842). We found negative correlation between orexin A and age (r = -0.5395; p<0.0001), body height (r = -0.4751; p=0.0002), body weight (r = -0.4030; p=0.0017) and BMI (r = -0.2607; p=0.0481). No correlation was found between orexin A and IGF-1, IGFBP-3 or leptin. Orexin A plasma levels increased during body weight loss, whereas the reverse was true for leptin levels. These findings support the hypothesis that orexin A may be involved in regulation of nutritional status in children., J. Bronský, J. Nedvídková, H. Zamrazilová, M. Pechová, M. Chada, K. Kotaška, J. Nevoral, R. Průša., and Obsahuje bibliografii a bibliografické odkazy
Dynamic changes of neoxanthin (NEO), violaxanthin (VIO), anteraxanthin (ANT), zeaxanthin (ZEA), chlorophyll (Chl) a, Chl b, α-carotene, β-carotene, and their behaviour under increasing duration of high irradiance (HI) were investigated in the soybean hypocotyl callus culture. The calli were induced on solid (1.1 % agar) MS medium (pH 5.8) supplemented with 4.52 μM 2,4-D, 2.32 μM kinetin, and 3 % sucrose. After 30 d of culture, the green calli were irradiated with "white light" (133W m-2) for 0, 3.5, and 24 h. HPLC profiles were separated on a C18 column. With increasing duration of HI, the content of total carotenoids (Cars) increased, but the ratio of Chl a+b/Cars decreased. With lengthening the duration of HI, there was induction of ZEA. Contents of ANT, α-carotene, and β-carotene remained nearly constant, but ratio of ZEA/Chl a+b increased with lengthening the HI duration. and D. M. Pandey, K. H. Kim, U. D. Yeo.
This paper studies the dynamic coverage control problem for cooperative region reconnaissance where a group of agents are required to reconnoitre a given region. The main challenge of this problem is that the sensing region of each agent is an ellipse. This modeling results in asymmetric(directed) interactions among agents. First, the region reconnaissance is formulated as a coverage problem, where each point in the given region should be surveyed until a preset level is achieved. Then, a coverage control law is designed that minimizes coverage performance index by finite switches between nominal control laws and perturbation control law. Finally, numerical simulations are provided to indicate the efficiency of the proposed control law.
Dynamic properties of two similar, parallel, one-sided clamped beams connected by a damping element on their free ends are analytically and numerically investigated. A harmonic motion excites the end of one of these beams. The main attention is given to the ascertaining of response curves deflection shapes of beams and their stresses in roots at different orientations and levels of damping force. and Obsahuje seznam literatury
This paper proposes a general framework to compare the strength of the dependence in survival models, as time changes, i.e. given remaining lifetimes X, to compare the dependence of X given X>t, and X given X>s, where s>t. More precisely, analytical results will be obtained in the case the survival copula of X is either Archimedean or a distorted copula. The case of a frailty based model will also be discussed in details.
The paper deals with mathematical modelling of dynamic response of the electric locomotive wheelset drive caused by short-circuit traction motor torque. The individual wheelset drive is composed of five subsystems - rotor of the traction motor with driving gear, driven gear, stator of the traction motor with gear housing, hollow graduated shaft with clutches and wheelset. The couplings between subsystems are linearized in dependence on longitudinal creepage and locomotive forward velocity before sudden short-circuit in the asynchronous traction motor. In comparison with previous models of the wheelset drives, the rotor of the electromotor is characterized by flexible shaft suppported on flexible rolling-element bearings. The sheet metal packjet of cylindrical shape is connected by parallel cooper bars with two short circuit rings. In conseqquence of strong excitation an interruption of gear mesh can be observed. This nonlinear effect and dynamic load of individual wheelset drive with large number of DOF is investigated using the condensed mathematical model created by model synthesis method. and Obsahuje seznam literatury
The paper deals with the mathematical modelling and the computer simulation of forced vibrations of the reactor core barrel excited by pressure pulsations generated by main circulation pumps. The modelling is focused on a possible core barrel flange slip along a pressure vessel flange. The slip in this internal reactor linkage is analysed providing the solid friction and the backlash between slip tongues of the pressure vessel flange and grooves in the core barrel flange. The impact motion can produce an excessive abrasive wear of the tongues and grooves. A guarantee of the fail-safe operation is achieved by calculated pre- stressing of toroidal tubes inserted between the upper flange of the core barrel and the pressure vessel cover. and Obsahuje seznam literatury
We model a market with multiple liquidity takers and a single market maker maximizing his discounted consumption while keeping a prescribed probability of bankruptcy. We show that, given this setting, spread and price bias (a difference between the midpoint- and the expected fair price) depend solely on the MM's inventory and his uncertainty concerning the fair price. Tested on ten-second data from ten US electronic markets, our model gives significant results with the price bias decreasing in the inventory and increasing in the uncertainty and with the spread mostly increasing in the uncertainty.
A topologically oriented neural network is very efficient in real-time path planning of a mobile robot in dynamic environments. Using a dynamic recurrent neural network to solve the partial differential equation of a potential field in a discrete manner, the problem of obstacle avoidance and path planning of a moving robot can be efficiently solved. A dimensional network used to represent the topology of the robot's workspace, where each network node represents a state associated with a local workspace point. In this paper, two approaches associated with different boundary conditions are proposed, namely, Dirichlet and Neumann conditions. The first approach relies on a field of attraction distributed around the moving target, acting as a unique local extreme in the local network space. The steepest gradients of the network state variables will aim towards the source of the potential field. The second approach considers two attractive and repulsive potential sources associated with the start and destination points. A dynamic neural mesh is used to model the robot workspace. A simulation package has been built and extensive computer experiments were conducted to demonstrate and validate the reliability of the presented approach.
We investigate the problem of power utility maximization considering risk management and strategy constraints. The aim of this paper is to obtain admissible dynamic portfolio strategies. In case the floor is guaranteed with probability one, we provide two admissible solutions, the option based portfolio insurance in the constrained model, and the alternative method and show that none of the solutions dominate the other. In case the floor is guaranteed partially, we provide one admissible solution, the portfolio insurance with spreads.