426 research outputs found
The Raman spectra of PbTiO sub 3 and solid solutions of NaTaO sub 3-KTaO sub 3 and KTaO sub 3-KNbO sub 3
Raman spectra of lead titanium trioxide and solid solutions of sodium tantalum trioxide-potassium tantalum trioxide and potassium niobium trioxid
Optical and Infrared Spectroscopy
Contains research objectives, summary of research and reports on four research projects.Joint Services Electronics Programs (U. S. Army, U.S. Navy, and U. S. Air Force) under Contract DA 28-043-AMC-02536(E)National Aeronautics and Space Administration (Grant NGR-22-009-237)U. S. Air Force Cambridge Research Laboratories Contract AF 19(628)-606
Proposal for generating and detecting multi-qubit GHZ states in circuit QED
We propose methods for the preparation and entanglement detection of
multi-qubit GHZ states in circuit quantum electrodynamics. Using quantum
trajectory simulations appropriate for the situation of a weak continuous
measurement, we show that the joint dispersive readout of several qubits can be
utilized for the probabilistic production of high-fidelity GHZ states. When
employing a nonlinear filter on the recorded homodyne signal, the selected
states are found to exhibit values of the Bell-Mermin operator exceeding 2
under realistic conditions. We discuss the potential of the dispersive readout
to demonstrate a violation of the Mermin bound, and present a measurement
scheme avoiding the necessity for full detector tomography.Comment: 9 pages, 5 figure
Swedish Future Surface Ships and Submarines
Cuts in military spending are now an international reality, and Sweden is no exception. The defence of Sweden, however, is more than a question of money. Our neutrality policy is no longer an end in itself but a tool that it is possible to discuss. The preservation of our compulsory service system is also under debate because it is obvious that we cannot finance the existing large army if we are also to possess the quality and readiness that we need. A structural reorganization in defence is now taking place, and it is evident that aspects of our defence industry are in jeopardy
Fat-Holding in Hamburgers as Influenced by the Different Constituents of Beef Adipose Tissue
The effects of addition of adipose tissue, rendered fat, rendered fat + the separated connective tissue and rendered fat + gelatin, respectively, were compared on the fat-holding properties of hamburgers upon heating. The fat losses on frying (175 °C, 3.5 minutes on each side) were substantially less than in the net test (cooking in a water bath at 77 oc for 35 minutes, followed by a centrifugation step). Fat losses during frying were governed both by the instability of the fat and the migration of the fat out of the product. The fat losses determined by the net test, however, reflected only the instability of the fat, as the effect of the migration of the fat out of the product was minimized, due to the centrifugation step. Fat-holding on frying was the best when fat was added in the form of fat cells and when an increased amount of connective tissue was added. On the contrary, fat-holding in the net test was be.st, when the fat was emulsified to smaller droplets with gelatin as an emulsifier. These observations suggest that the migration of the fat out of the hamburger is the most important factor, governing fat-holding in hamburgers on frying, whereas for the net test the instability of the fat per se seemed to be more essential
Dietary soy and meat proteins induce distinct physiological and gene expression changes in rats
This study reports on a comprehensive comparison of the effects of soy and meat proteins given at the recommended level on physiological markers of metabolic syndrome and the hepatic transcriptome. Male rats were fed semi-synthetic diets for 1 wk that differed only regarding protein source, with casein serving as reference. Body weight gain and adipose tissue mass were significantly reduced by soy but not meat proteins. The insulin resistance index was improved by soy, and to a lesser extent by meat proteins. Liver triacylglycerol contents were reduced by both protein sources, which coincided with increased plasma triacylglycerol concentrations. Both soy and meat proteins changed plasma amino acid patterns. The expression of 1571 and 1369 genes were altered by soy and meat proteins respectively. Functional classification revealed that lipid, energy and amino acid metabolic pathways, as well as insulin signaling pathways were regulated differently by soy and meat proteins. Several transcriptional regulators, including NFE2L2, ATF4, Srebf1 and Rictor were identified as potential key upstream regulators. These results suggest that soy and meat proteins induce distinct physiological and gene expression responses in rats and provide novel evidence and suggestions for the health effects of different protein sources in human diets
Adaptive Mesh Refinement for Characteristic Grids
I consider techniques for Berger-Oliger adaptive mesh refinement (AMR) when
numerically solving partial differential equations with wave-like solutions,
using characteristic (double-null) grids. Such AMR algorithms are naturally
recursive, and the best-known past Berger-Oliger characteristic AMR algorithm,
that of Pretorius & Lehner (J. Comp. Phys. 198 (2004), 10), recurses on
individual "diamond" characteristic grid cells. This leads to the use of
fine-grained memory management, with individual grid cells kept in
2-dimensional linked lists at each refinement level. This complicates the
implementation and adds overhead in both space and time.
Here I describe a Berger-Oliger characteristic AMR algorithm which instead
recurses on null \emph{slices}. This algorithm is very similar to the usual
Cauchy Berger-Oliger algorithm, and uses relatively coarse-grained memory
management, allowing entire null slices to be stored in contiguous arrays in
memory. The algorithm is very efficient in both space and time.
I describe discretizations yielding both 2nd and 4th order global accuracy.
My code implementing the algorithm described here is included in the electronic
supplementary materials accompanying this paper, and is freely available to
other researchers under the terms of the GNU general public license.Comment: 37 pages, 15 figures (40 eps figure files, 8 of them color; all are
viewable ok in black-and-white), 1 mpeg movie, uses Springer-Verlag svjour3
document class, includes C++ source code. Changes from v1: revised in
response to referee comments: many references added, new figure added to
better explain the algorithm, other small changes, C++ code updated to latest
versio
Sex-biased parental care and sexual size dimorphism in a provisioning arthropod
The diverse selection pressures driving the evolution of sexual size dimorphism (SSD) have long been debated. While the balance between fecundity selection and sexual selection has received much attention, explanations based on sex-specific ecology have proven harder to test. In ectotherms, females are typically larger than males, and this is frequently thought to be because size constrains female fecundity more than it constrains male mating success. However, SSD could additionally reflect maternal care strategies. Under this hypothesis, females are relatively larger where reproduction requires greater maximum maternal effort – for example where mothers transport heavy provisions to nests.
To test this hypothesis we focussed on digger wasps (Hymenoptera: Ammophilini), a relatively homogeneous group in which only females provision offspring. In some species, a single large prey item, up to 10 times the mother’s weight, must be carried to each burrow on foot; other species provide many small prey, each flown individually to the nest.
We found more pronounced female-biased SSD in species where females carry single, heavy prey. More generally, SSD was negatively correlated with numbers of prey provided per offspring. Females provisioning multiple small items had longer wings and thoraxes, probably because smaller prey are carried in flight.
Despite much theorising, few empirical studies have tested how sex-biased parental care can affect SSD. Our study reveals that such costs can be associated with the evolution of dimorphism, and this should be investigated in other clades where parental care costs differ between sexes and species
Quantum feedback control of a superconducting qubit: Persistent Rabi oscillations
The act of measurement bridges the quantum and classical worlds by projecting
a superposition of possible states into a single, albeit probabilistic,
outcome. The time-scale of this "instantaneous" process can be stretched using
weak measurements so that it takes the form of a gradual random walk towards a
final state. Remarkably, the interim measurement record is sufficient to
continuously track and steer the quantum state using feedback. We monitor the
dynamics of a resonantly driven quantum two-level system -- a superconducting
quantum bit --using a near-noiseless parametric amplifier. The high-fidelity
measurement output is used to actively stabilize the phase of Rabi
oscillations, enabling them to persist indefinitely. This new functionality
shows promise for fighting decoherence and defines a path for continuous
quantum error correction.Comment: Manuscript: 5 Pages and 3 figures ; Supplementary Information: 9
pages and 3 figure
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