49,162 research outputs found
An evaluation of the NASA/GSFC Barnes field spectral reflecometer model 14-758, using signal/noise as a measure of utility
A Barnes field spectral reflectometer which collected information in 373 channels covering the region from 0.4 to 2.5 micrometers was assessed for signal utility. A band was judged unsatisfactory if the probability was 0.1 or greater than its signal to noise ratio was less than eight to one. For each of the bands the probability of a noisy observation was estimated under a binomial assumption from a set of field crop spectra covering an entire growing season. A 95% confidence interval was calculated about each estimate and bands whose lower confidence limits were greater than 0.1 were judged unacceptable. As a result, 283 channels were deemed statistically satisfactory. Excluded channels correspond to portions of the electromagnetic spectrum (EMS) where high atmospheric absorption and filter wheel overlap occur. In addition, the analyses uncovered intervals of unsatisfactory detection capability within the blue, red and far infrared regions of vegetation spectra. From the results of the analysis it was recommended that 90 channels monitored by the instrument under consideration be eliminated from future studies. These channels are tabulated and discussed
Equilibrium fluctuation theorems compatible with anomalous response
Previously, we have derived a generalization of the canonical fluctuation
relation between heat capacity and energy fluctuations , which is able to describe the existence of macrostates with negative
heat capacities . In this work, we extend our previous results for an
equilibrium situation with several control parameters to account for the
existence of states with anomalous values in other response functions. Our
analysis leads to the derivation of three different equilibrium fluctuation
theorems: the \textit{fundamental and the complementary fluctuation theorems},
which represent the generalization of two fluctuation identities already
obtained in previous works, and the \textit{associated fluctuation theorem}, a
result that has no counterpart in the framework of Boltzmann-Gibbs
distributions. These results are applied to study the anomalous susceptibility
of a ferromagnetic system, in particular, the case of 2D Ising model.Comment: Extended version of the paper published in JSTA
Research on gravitational mass sensors Quarterly progress report no. 1, 15 Oct. 1964 - 14 Jan. 1965
Lunar orbiter and deep space probe gravitational sensor for determining mass distribution of moon and asteroid
Research on gravitational mass sensors quarterly progress report no. 2, 15 jan. - 14 apr. 1965
Cruciform sensor head, phase shift tuned amplifier, and air bearing support for sensor for detecting presence of small moving mass through gravitational interaction
A Topos Foundation for Theories of Physics: IV. Categories of Systems
This paper is the fourth in a series whose goal is to develop a fundamentally
new way of building theories of physics. The motivation comes from a desire to
address certain deep issues that arise in the quantum theory of gravity. Our
basic contention is that constructing a theory of physics is equivalent to
finding a representation in a topos of a certain formal language that is
attached to the system. Classical physics arises when the topos is the category
of sets. Other types of theory employ a different topos. The previous papers in
this series are concerned with implementing this programme for a single system.
In the present paper, we turn to considering a collection of systems: in
particular, we are interested in the relation between the topos representation
for a composite system, and the representations for its constituents. We also
study this problem for the disjoint sum of two systems. Our approach to these
matters is to construct a category of systems and to find a topos
representation of the entire category.Comment: 38 pages, no figure
Universal homogeneous causal sets
Causal sets are particular partially ordered sets which have been proposed as
a basic model for discrete space-time in quantum gravity. We show that the
class C of all countable past-finite causal sets contains a unique causal set
(U,<) which is universal (i.e., any member of C can be embedded into (U,<)) and
homogeneous (i.e., (U,<) has maximal degree of symmetry). Moreover, (U,<) can
be constructed both probabilistically and explicitly. In contrast, the larger
class of all countable causal sets does not contain a universal object.Comment: 14 page
Non-Bilocal Measurement via Entangled State
Two observers, who share a pair of particles in an entangled mixed state, can
use it to perform some non-bilocal measurement over another bipartite system.
In particular, one can construct a specific game played by the observers
against a coordinator, in which they can score better than a pair of observers
who only share a classical communication channel.Comment: 6 pages. minor change
Electromagnetic Fields of Separable Space-Times
Carter derived the forms of the metric and the vector potentials of the
space-times in which the relativistic Schrodinger equation for the motion of a
charged particle separates. Here we show that on each `spheroidal' surface a
rotation rate exists such that relative to those rotating axes the electric and
magnetic fields are parallel and orthogonal to the spheroid which is thus an
equipotential in those axes. All the finite Carter separable systems without
magnetic monopoles or gravomagnetic NUT monopoles have the same gyromagnetic
ratio as the Dirac electron.Comment: 9 pages; accepted for publication in Class. Quantum Gra
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