14,511 research outputs found
Planetary science questions for the manned exploration of Mars
A major goal of a manned Mars mission is to explore the planet and to investigate scientific questions for which the intensive study of Mars is essential. The systematic exploration of planets was outlined by the National Academy of Science. The nearest analogy to the manned Mars mission is the Apollo program and manned missions to the Moon, but the analogy is limited. The case is argued here that Mars may have to be explored far more systematically than was the pre-Apollo Moon to provide the detailed information necessary if plans are made to use any of the resources available on Mars. Viking missions provided a wealth of information, yet there are great gaps in the fundamental knowledge of essential facts such as the properties of the Martian surface materials and their interaction with the atmosphere. Building on a strong data base of precursor missions, human exploration will allow great leaps in understanding the Martian environment and geologic history and its evolutionary role in the solar system
A Way Out of the Quantum Trap
We review Event Enhanced Quantum Theory (EEQT). In Section 1 we address the
question "Is Quantum Theory the Last Word". In particular we respond to some of
recent challenging staments of H.P. Stapp. We also discuss a possible future of
the quantum paradigm - see also Section 5. In Section 2 we give a short sketch
of EEQT. Examples are given in Section 3. Section 3.3 discusses a completely
new phenomenon - chaos and fractal-like phenomena caused by a simultaneous
"measurement" of several non-commuting observables (we include picture of
Barnsley's IFS on unit sphere of a Hilbert space). In Section 4 we answer
"Frequently Asked Questions" concerning EEQT.Comment: Replacement. Corrected affiliation. Latex, one .jpg figure. To appear
in Proc. Conf. Relativistic Quantum Measurements, Napoli 1998, Ed. F.
Petruccion
Nonnegative Feynman-Kac Kernels in Schr\"{o}dinger's Interpolation Problem
The existing formulations of the Schr\"{o}dinger interpolating dynamics,
which is constrained by the prescribed input-output statistics data, utilize
strictly positive Feynman-Kac kernels. This implies that the related Markov
diffusion processes admit vanishing probability densities only at the
boundaries of the spatial volume confining the process. We extend the framework
to encompass singular potentials and associated nonnegative Feynman-Kac-type
kernels. It allows to deal with general nonnegative solutions of the
Schr\"{o}dinger boundary data problem. The resulting stochastic processes are
capable of both developing and destroying nodes (zeros) of probability
densities in the course of their evolution.Comment: Latex file, 25 p
Radar response from vegetation with nodal structure
Radar images from the SEASAT synthetic aperture radar (SAR) produced unusually high returns from corn and sorghum fields, which seem to indicate a correlation between nodal separation in the stalk and the wavelength of the radar. These images also show no difference in return from standing or harvested corn. Further investigation using images from the Shuttle Imaging Radar (SIR-A) substantiated these observations and showed a degradation of the high return with time after harvest. From portions of corn and sweet sorghum stalks that were sampled to measure stalk water content, it was determined that near and after maturity the water becomes more concentrated in the stalk nodes. The stalk then becomes a linear sequence of alternating dielectrics as opposed to a long slender cylinder with uniform dielectric properties
Case records of the Massachusetts General Hospital. Case 1-2014. A 32-year-old man with loss of vision and a rash
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