2,306 research outputs found
Somatostatin agonist pasireotide inhibits exercise stimulated growth in the male Siberian hamster (Phodopus sungorus)
R.Dumbell was supported by a University of Aberdeen PhD studentship and a research visit grant awarded by the British Society of Neuroendocrinology. Further support was provided by the Scottish Government Rural and Environment Science and Analytical Services Division (Barrett and the German Research Foundation (DFG; STE 331/8-1; Steinlechner lab). We are grateful for technical assistance from Dana Wilson at RINH and Siegried Hiliken at UVMH, and thank Dr Claus-Dieter Mayer of Biomathematics & Statistics Scotland for valuable advice on statistical analysis.Peer reviewedPostprin
Composition of Ni2+ cation solvation shell in NiCl2âmethanol solution by multinuclear NMR
1H-, 2H- and 13C-NMR spectra have been used to test the Ni2+ solvation shell composition in the 1.1 molal methanol solution of NiCl2. It has been confirmed that Clâ anion takes part in the nearest environment of Ni2+ cation at all the temperatures investigated. Using 2H-NMR allowed us to detect for the first time OD-signal of methanol in the primary solvation shell of Ni2+ cation. Both 2H- and 13C-NMR spectra show that the composition of the cation solvation shell becomes more complicated at temperatures lower than 220âK
Roughness and Finite Size Effect in the NYSE Stock-Price Fluctuations
We consider the roughness properties of NYSE (New York Stock Exchange)
stock-price fluctuations. The statistical properties of the data are relatively
homogeneous within the same day but the large jumps between different days
prevent the extension of the analysis to large times. This leads to intrinsic
finite size effects which alter the apparent Hurst (H) exponent. We show, by
analytical methods, that finite size effects always lead to an enhancement of
H. We then consider the effect of fat tails on the analysis of the roughness
and show that the finite size effects are strongly enhanced by the fat tails.
The non stationarity of the stock price dynamics also enhances the finite size
effects which, in principle, can become important even in the asymptotic
regime. We then compute the Hurst exponent for a set of stocks of the NYSE and
argue that the interpretation of the value of H is highly ambiguous in view of
the above results. Finally we propose an alternative determination of the
roughness in terms of the fluctuations from moving averages with variable
characteristic times. This permits to eliminate most of the previous problems
and to characterize the roughness in useful way. In particular this approach
corresponds to the automatic elimination of trends at any scale.Comment: 13 pages, 11 fugure
Two Algebraic Process Semantics for Contextual Nets
We show that the so-called 'Petri nets are monoids' approach initiated by Meseguer and Montanari can be extended from ordinary place/transition Petri nets to contextual nets by considering suitable non-free monoids of places. The algebraic characterizations of net concurrent computations we provide cover both the collective and the individual token philosophy, uniformly along the two interpretations, and coincide with the classical proposals for place/transition Petri nets in the absence of read-arcs
Zoobenthic study of biological state of small lakes in the joint Finnish, Norwegian and Russian border area
Appendix 6/15 of the publication "State of the environment in the Norwegian, Finnish and Russian border area 2007" (The Finnish Environment 6/2007)
Exact Results for the Roughness of a Finite Size Random Walk
We consider the role of finite size effects on the value of the effective
Hurst exponent H. This problem is motivated by the properties of the high
frequency daily stock-prices. For a finite size random walk we derive some
exact results based on Spitzer's identity. The conclusion is that finite size
effects strongly enhance the value of H and the convergency to the asymptotic
value (H=1/2) is rather slow. This result has a series of conceptual and
practical implication which we discuss.Comment: 5 pages, 3 figure
Ion Sources, Operation and Development
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
Electric field generation by the electron beam filamentation instability: Filament size effects
The filamentation instability (FI) of counter-propagating beams of electrons
is modelled with a particle-in-cell simulation in one spatial dimension and
with a high statistical plasma representation. The simulation direction is
orthogonal to the beam velocity vector. Both electron beams have initially
equal densities, temperatures and moduli of their nonrelativistic mean
velocities. The FI is electromagnetic in this case. A previous study of a small
filament demonstrated, that the magnetic pressure gradient force (MPGF) results
in a nonlinearly driven electrostatic field. The probably small contribution of
the thermal pressure gradient to the force balance implied, that the
electrostatic field performed undamped oscillations around a background
electric field. Here we consider larger filaments, which reach a stronger
electrostatic potential when they saturate. The electron heating is enhanced
and electrostatic electron phase space holes form. The competition of several
smaller filaments, which grow simultaneously with the large filament, also
perturbs the balance between the electrostatic and magnetic fields. The
oscillations are damped but the final electric field amplitude is still
determined by the MPGF.Comment: 14 pages, 10 plots, accepted for publication in Physica Script
Magnetohydrodynamic waves in the pulsar magnetosphere
MHD waves can be responsible for plasma fluctuations and short-term
variations of the pulsar emission. We consider the properties of plane and
cylindrical waves that can exist in the force-free magnetosphere. Waves are
considered by means of a linear analysis of the force-free MHD equations. We
argue that these particular types of waves can exist in the magnetosphere of
pulsars. These waves are closely related to the Alfven waves of the standard
magnetohydrodynamics but are modified by the force-free condition and non-zero
charge density. We derive the dispersion relation for magnetospheric waves and
show that the wave periods are likely within the range \sim 10^{-2}-10^(-4} s
depending on the magnetospheric parameters.Comment: 4 pages; to appear in Astronomy and Astrophysic
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