Plasma neuropeptide-Y levels, monoamine metabolism, electrolyte excretion and drinking behavior in children with attention-deficit hyperactivity disorder

Introduction: This study was conducted against a background of the following four points: a) increased drinking behavior in children with attention-deficit hyperactivity disorder (ADHD), b) the parallel between some behaviours associated with ADHD and with hypertension, c) the use of the spontaneously hypertensive rat as a model for ADHD, and d) similarities in the changes of neuropeptide-Y (NPY) and catecholamine in the studies of hypertension and drinking, Methods: Measures of NPY, catecholamines and electrolyte balance were compared in the plasma and urine of healthy children and those with ADHD. Drinking was monitored during three hours of neuropsychological tests over two days in 14 ADHD (mean 9.8 years-of-age) and 9 healthy children (10.6 years-of-age). Results: Patients drank 4 times more water and showed twice the levels of NPY in controls. In controls there were positive and in patients there were negative relationships for NPY with drinking and restless behavior. Patients' plasma levels of norepinephrine (NE) and epinephrine were slightly elevated, but urinary levels of NE and the serotonin metabolite were markedly increased. Urinary excretion rates for sodium (not potassium), phosphate and, especially calcium were decreased in patients. NPY levels were inversely related to calcium excretion and drinking inversely to sodium circulating (but positively with potassium and phosphate excretion). Conclusions: Increases of drinking and increased levels of circulating NPY in ADHD children and decreased electrolyte excretion may reflect a common disturbance in the homeostatic control of metabolism.This may contribute to the impairments of attentional and behavioural control typical of ADHD children

Earth resources-regional transfer activity contracts review

A regional transfer activity contracts review held by the Earth Resources Office was summarized. Contracts in the earth resources field primarily directed toward applications of satellite data and technology in solution of state and regional problems were reviewed. A summary of the progress of each contract was given in order to share experiences of researchers across a seven state region. The region included Missouri, Kentucky, Tennessee, Mississippi, Alabama, Georgia, and North Carolina. Research in several earth science disciplines included forestry, limnology, water resources, land use, geology, and mathematical modeling. The use of computers for establishment of information retrieval systems was also emphasized

Study of methane fuel for subsonic transport aircraft

The cost and performance were defined for commercial transport using liquid methane including its fuel system and the ground facility complex required for the processing and storage of methane. A cost and performance comparison was made with Jet A and hydrogen powered aircraft of the same payload and range capability. Extensive design work was done on cryogenic fuel tanks, insulation systems as well as the fuel system itself. Three candidate fuel tank locations were evaluated, i.e., fuselage tanks, wing tanks or external pylon tanks

Expansion algorithm for the density matrix

A purification algorithm for expanding the single-particle density matrix in terms of the Hamiltonian operator is proposed. The scheme works with a predefined occupation and requires less than half the number of matrix-matrix multiplications compared to existing methods at low (90%) occupancy. The expansion can be used with a fixed chemical potential in which case it is an asymmetric generalization of and a substantial improvement over grand canonical McWeeny purification. It is shown that the computational complexity, measured as number of matrix multiplications, essentially is independent of system size even for metallic materials with a vanishing band gap.Comment: 5 pages, 4 figures, to appear in Phys. Rev.

Spicules and the effect of rigid rods on enclosing membrane tubes

Membrane tubes (spicules) arise in cells, or artificial membranes, in the nonlinear deformation regime due to, e.g. the growth of microtubules, actin filaments or sickle hemoglobin fibers towards a membrane. We calculate the axial force exerted by the cylindrical membrane tube, and its average radius, by taking into account steric interactions between the fluctuating membrane and the enclosed rod. The force required to confine a fluctuating membrane near the surface of the enclosed rod diverges as the separation approaches zero. This results in a smooth crossover of the axial force between a square root and a linear dependence on the membrane tension as the tension increases and the tube radius shrinks. This crossover can occur at the most physiologically relevant membrane tensions. Our work may be important in (i) interpreting experiments in which axial force is related to the tube radius or membrane tension (ii) dynamical theories for biopolymer growth in narrow tubes where these fluctuation effects control the tube radius.Comment: 10 pages, 1 figur

The effects of bell vibrations on the sound of the modern trumpet

The acoustic spectrum of a modern trumpet with the bell section heavily damped has been compared to the spectrum of the same instrument with the bell section left free to vibrate. Measurements of the amplitude of vibration indicate that the damping significantly reduces the movement of the metal, and a corresponding change in the acoustic spectrum between the two cases is found. It is shown that the relative power in the fundamental may change by more than 3 dB when the vibrations in the bell section are damped. Two possible causes for the effects are considered: a change in input impedance, and the transfer of mechanical vibrations through the instrument to the lips. Results of modelling and experiments are presented that indicate the latter is the more plausible explanation; however, the etiology of the effect is still unknown