24,751 research outputs found
Fisher information in quantum statistics
Braunstein and Caves (1994) proposed to use Helstrom's {\em quantum
information} number to define, meaningfully, a metric on the set of all
possible states of a given quantum system. They showed that the quantum
information is nothing else than the maximal Fisher information in a
measurement of the quantum system, maximized over all possible measurements.
Combining this fact with classical statistical results, they argued that the
quantum information determines the asymptotically optimal rate at which
neighbouring states on some smooth curve can be distinguished, based on
arbitrary measurements on identical copies of the given quantum system.
We show that the measurement which maximizes the Fisher information typically
depends on the true, unknown, state of the quantum system. We close the
resulting loophole in the argument by showing that one can still achieve the
same, optimal, rate of distinguishability, by a two stage adaptive measurement
procedure.
When we consider states lying not on a smooth curve, but on a manifold of
higher dimension, the situation becomes much more complex. We show that the
notion of ``distinguishability of close-by states'' depends strongly on the
measurement resources one allows oneself, and on a further specification of the
task at hand. The quantum information matrix no longer seems to play a central
role.Comment: This version replaces the previous versions of February 1999 (titled
'An Example of Non-Attainability of Expected Quantum Information') and that
of November 1999. Proofs and results are much improved. To appear in J. Phys.
Behavioural compensatory adjustments to exercise training in overweight women
<b>Purpose:</b> To examine extent to which changes in non-exercise physical activity contribute to individual differences in body fat loss induced by exercise programs. <b>Methods:</b> Thirty four overweight/obese sedentary women (age: 31.7 +/- 8.1 years, BMI: 29.3 +/- 4.3 kg m-2) exercised for 8 weeks. Body composition, total energy expenditure (TEE), exercise EE (ExEE), activity EE (AEE) calculated as energy expenditure of all active activities minus ExEE, sedentary EE (SEDEE), sleeping EE (SEE), and energy intake were determined before and during the last week of the exercise intervention. <b>Results:</b> Over the 8-week exercise program net ExEE was 30.2 +/- 12.6 MJ and based on this, body fat loss was predicted to be 0.8 +/- 0.2 kg. For the group as a whole, change in body fat (-0.0 +/- 0.2 kg) was not significant but individual body fat changes ranged from -3.2 kg to +2.6 kg. Eleven participants achieved equal or more than the predicted body fat loss and were classified as 'Responders' and 23 subjects achieved less than the predicted fat loss and were classified as 'Non-responders'. In the group as a whole, daily TEE was increased by 0.62 +/- 0.30 MJ (p<0.05) and the change tended to be different between groups (Responders, +1.44 +/- 0.49 MJ; Non-responders, +0.29 +/- 0.36 MJ, p=0.08). Changes in daily AEE of Responders and Non-responders differed significantly between groups (Responders, +0.79 +/- 0.50 MJ; Non-responders, -0.62 +/- 0.39 MJ, p<0.05). There were no differences between Responders and Non-responders for changes in SEDEE and SEE or energy intake. <b>Conclusion:</b> Overweight and obese women who during exercise intervention achieve lower than predicted fat loss are compensating by being less active outside exercise sessions
Determination of total potentially available nucleosides in bovine milk
Bovine colostrum and milk samples were collected from two herds over the course of the first month post-partum, pooled for each herd by stage of lactation and total potentially available nucleosides were determined. Sample analysis consisted of parallel enzymatic treatments, phenylboronate clean-up, and liquid chromatography to quantify contributions of nucleosides, monomeric nucleotides, nucleotide adducts, and polymeric nucleotides to the available nucleosides pool. Bovine colostrum contained high levels of nucleosides and monomeric nucleotides, which rapidly decreased as lactation progressed into transitional milk. Mature milk was relatively consistent in nucleoside and monomeric nucleotide concentrations from approximately the tenth day post-partum. Differences in concentrations between summer-milk and winter-milk herds were largely attributable to variability in uridine and monomeric nucleotide concentrations
The 2018 Midterm Election: Nevada and the Nation Post-Election Analysis
Brookings Mountain West, in partnership with CSUN, was pleased to present part two of a two-part analysis on the 2018 Midterm elections. The 2018 Midterms included elections for all 435 members of the House of Representatives, including four seats in Nevada. In the U.S. Senate, 34 seats were up for election, including one seat in Nevada. Across the United States, 36 states elected governors, including the State of Nevada. The Democratic Party sought to flip a minimum of 24 seats to become the majority party in House and 2 seats to become the majority party in the Senate. Two Mountain West states, Nevada and Arizona, presented the best opportunity for the Democratic Party to flip seats in the U.S. Senate. Republicans looked to flip seats in 10 states that Donald Trump won in 2016. Panelists reacted to the policy issues and voting trends that resulted from the 2018 Midterm elections
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LENS® and SFF: Enabling Technologies for Optimized Structures
Optimized, lightweight, high-strength structures are needed in many applications from aerospace
to automotive. In pursuit of such structures, there have been proposed analytical solutions and
some specialized FEA solutions for specific structures such as automobile frames. However,
generalized 3D optimization methods have been unavailable for use by most designers.
Moreover, in the cases where optimized structural solutions are available, they are often hollow,
curving, thin wall structures that cannot be fabricated by conventional manufacturing methods.
Researchers at Sandia National Laboratories and the University of Rhode Island teamed to solve
these problems. The team has been pursuing two methods of optimizing models for generalized
loading conditions, and also has been investigating the methods needed to fabricate these
structures using Laser Engineered Net Shaping™ (LENS®) and other rapid prototyping
methods. These solid freeform fabrication (SFF) methods offer the unique ability to make
hollow, high aspect ratio features out of many materials. The manufacturing development
required for LENS to make these complex structures has included the addition of rotational axes
to Sandia’s LENS machine bringing the total to 5 controlled axes. The additional axes have
required new efforts in process planning. Several of the unique structures that are only now
possible through the use of SFF technology are shown as part of the discussion of this exciting
new application for SFF.Mechanical Engineerin
Hybrid Superconductor-Quantum Point Contact Devices using InSb Nanowires
Proposals for studying topological superconductivity and Majorana bound
states in nanowires proximity coupled to superconductors require that transport
in the nanowire is ballistic. Previous work on hybrid nanowire-superconductor
systems has shown evidence for Majorana bound states, but these experiments
were also marked by disorder, which disrupts ballistic transport. In this
letter, we demonstrate ballistic transport in InSb nanowires interfaced
directly with superconducting Al by observing quantized conductance at
zero-magnetic field. Additionally, we demonstrate that the nanowire is
proximity coupled to the superconducting contacts by observing Andreev
reflection. These results are important steps for robustly establishing
topological superconductivity in InSb nanowires
On-Bird Sound Recordings: Automatic Acoustic Recognition of Activities and Contexts
We introduce a novel approach to studying animal behaviour and the context in
which it occurs, through the use of microphone backpacks carried on the backs
of individual free-flying birds. These sensors are increasingly used by animal
behaviour researchers to study individual vocalisations of freely behaving
animals, even in the field. However such devices may record more than an
animals vocal behaviour, and have the potential to be used for investigating
specific activities (movement) and context (background) within which
vocalisations occur. To facilitate this approach, we investigate the automatic
annotation of such recordings through two different sound scene analysis
paradigms: a scene-classification method using feature learning, and an
event-detection method using probabilistic latent component analysis (PLCA). We
analyse recordings made with Eurasian jackdaws (Corvus monedula) in both
captive and field settings. Results are comparable with the state of the art in
sound scene analysis; we find that the current recognition quality level
enables scalable automatic annotation of audio logger data, given partial
annotation, but also find that individual differences between animals and/or
their backpacks limit the generalisation from one individual to another. we
consider the interrelation of 'scenes' and 'events' in this particular task,
and issues of temporal resolution
Use of Nearshore and Estuarine Areas of the Southeastern Bering Sea by Gray Whales (Eschrichtius robustus)
During spring aerial surveys of the coast of the southeastern Bering Sea significant numbers of gray whales were seen in nearshore waters along the north side of the Alaska Peninsula. Many (50-80%) of these animals were observed surfacing with mud trails or lying on their sides, characteristics both associated with feeding. A migration route close to shore (within 1-2 km) was used until whales neared Egegik Bay, where they began to head west 5-8 km offshore, across northern Bristol Bay. Smaller numbers of gray whales were present throughout summer in nearshore waters and estuaries along the north side of the Alaska Peninsula. At Nelson Lagoon gray whales normally used the lagoon in spring, were absent during early summer, returned in mid-summer, and then were present until late November when they departed for the wintering grounds. Gray whales were present in the lagoon most often during periods of peak tidal flow; those that appeared to be feeding were oriented into the current. Three behaviors that appeared to be associated with feeding were observed: side-feeding from a stationary position within shallow waters of lagoon channels, diving within the lagoon and in nearshore waters, and elliptical side-feeding in the surf zone along the outer coast. Large crustaceans of the genus Crangon were available to and probably eaten by gray whales at Nelson Lagoon.Key words: gray whale, Eschrichtius robustus, feeding, behavior, estuaries, Bering Sea, AlaskaMots clés: baleine grise de Californie, Eschrichtius robustus, alimentation, comportement, estuaires, mer de Béring, Alask
Radial Alignment in Simulated Clusters
Observational evidence for the radial alignment of satellites with their dark
matter host has been accumulating steadily in the past few years. The effect is
seen over a wide range of scales, from massive clusters of galaxies down to
galaxy-sized systems, yet the underlying physical mechanism has still not been
established. To this end, we have carried out a detailed analysis of the shapes
and orientations of dark matter substructures in high-resolution N-body
cosmological simulations. We find a strong tendency for radial alignment of the
substructure with its host halo: the distribution of halo major axes is very
anisotropic, with the majority pointing towards the center of mass of the host.
The alignment peaks once the sub-halo has passed the virial radius of the host
for the first time, but is not subsequently diluted, even after the halos have
gone through as many as four pericentric passages. This evidence points to the
existence of a very rapid dynamical mechanism acting on these systems and we
argue that tidal torquing throughout their orbits is the most likely candidate.Comment: v2: 13 pages, 10 figures, ApJ in press. Revisions include a new
section (4.2) comparing our results with observations, and a few added
reference
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