4,006 research outputs found
Fractal Strings and Multifractal Zeta Functions
For a Borel measure on the unit interval and a sequence of scales that tend
to zero, we define a one-parameter family of zeta functions called multifractal
zeta functions. These functions are a first attempt to associate a zeta
function to certain multifractal measures. However, we primarily show that they
associate a new zeta function, the topological zeta function, to a fractal
string in order to take into account the topology of its fractal boundary. This
expands upon the geometric information garnered by the traditional geometric
zeta function of a fractal string in the theory of complex dimensions. In
particular, one can distinguish between a fractal string whose boundary is the
classical Cantor set, and one whose boundary has a single limit point but has
the same sequence of lengths as the complement of the Cantor set. Later work
will address related, but somewhat different, approaches to multifractals
themselves, via zeta functions, partly motivated by the present paper.Comment: 32 pages, 9 figures. This revised version contains new sections and
figures illustrating the main results of this paper and recent results from
others. Sections 0, 2, and 6 have been significantly rewritte
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From Waste-Heat Recovery to Refrigeration: Compositional Tuning of Magnetocaloric Mn 1+ x Sb
The Long Term Stability of Oscillations During Thermonuclear X-ray Bursts: Constraining the Binary X-ray Mass Function
We report on the long term stability of the millisecond oscillations observed
with the Rossi X-ray Timing Explorer (RXTE) during thermonuclear X-ray bursts
from the low mass X-ray binaries (LMXB) 4U 1728-34 and 4U 1636-53. We show that
bursts from 4U 1728-34 spanning more than 1.5 years have observed asymptotic
oscillation periods which are within 0.2 microsec. of each other, well within
the magnitude which could be produced by the orbital motion of the neutron star
in a typical LMXB. This stability implies a timescale to change the oscillation
period of > 23,000 years, suggesting a highly stable process such as stellar
rotation as the oscillation mechanism. We show that period offsets in three
distinct bursts from 4U 1636-53 can be plausibly interpreted as due to orbital
motion of the neutron star in this 3.8 hour binary system. We discuss the
constraints on the mass function which can in principle be derived using this
technique.Comment: 11 pages, 4 figures. AASTeX, to be published in the Astrophysical
Journal Letter
Double radiative pion capture on hydrogen and deuterium and the nucleon's pion cloud
We report measurements of double radiative capture in pionic hydrogen and
pionic deuterium. The measurements were performed with the RMC spectrometer at
the TRIUMF cyclotron by recording photon pairs from pion stops in liquid
hydrogen and deuterium targets. We obtained absolute branching ratios of for hydrogen and for deuterium, and
relative branching ratios of double radiative capture to single radiative
capture of for hydrogen
and for
deuterium. For hydrogen, the measured branching ratio and photon energy-angle
distributions are in fair agreement with a reaction mechanism involving the
annihilation of the incident on the cloud of the target proton.
For deuterium, the measured branching ratio and energy-angle distributions are
qualitatively consistent with simple arguments for the expected role of the
spectator neutron. A comparison between our hydrogen and deuterium data and
earlier beryllium and carbon data reveals substantial changes in the relative
branching ratios and the energy-angle distributions and is in agreement with
the expected evolution of the reaction dynamics from an annihilation process in
S-state capture to a bremsstrahlung process in P-state capture. Lastly, we
comment on the relevance of the double radiative process to the investigation
of the charged pion polarizability and the in-medium pion field.Comment: 44 pages, 7 tables, 13 figures, submitted to Phys. Rev.
Avaliação da severidade da murcha de fusário em tomateiro em diferentes níveis de água no solo por meio do teor de clorollila das folhas.
O objetivo deste experimento foi avaliar a severidade da murcha de fusário em 4 diferentes niveis de água no solo por meio do teor de clorofila das folhas.Resumo 820-1
Avaliação da severidade da murcha de fusário em tomateiro em diferentes níveis de água no solo por meio da temperatura na superficie foliar.
O objetivo do trabalho foi avaliar o efeito do manejo de água de irrigação por meio de diferentes níveis de água no solo sobre o desenvolvimento temporal da murcha de fusário em tomateiro.Resumo 849-1
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