Control of the switching behavior of ferromagnetic nanowires using magnetostatic interactions

Magnetostatic interactions between two end-to-end Permalloy (Ni80Fe20) nanowires have been studied as a function of their separation, end shape, and width. The change in switching field increases as the wires become closer, with deviations from the switching field of an isolated wire of up to 40% observed. The sign of the change depends on the relative magnetization orientation of the two wires, with higher fields for parallel magnetization and lower fields for antiparallel magnetization. A wire end shape has a strong influence, with larger field variations being seen for flat-ended wires than wires with tapered ends. The micromagnetic modeling and experiments performed here were in good qualitative agreement. The experimental control of switching behavior of one nanowire with another was also demonstrated using magnetostatic interactions

The Public’s Reaction, Over Time, to the Findings of the Warren Report

Abstract From the moment President Kennedy was shot, the public had difficulty accepting Lee Harvey Oswald as the lone assassin, and spoke in terms of conspiracy. Polling data indicated that while Oswald may have participated in the plot, the majority believed others were also involved. Examining the public’s response to the vocal critics of the Warren Commission, the findings of both the Church Committee and the House Select Committee on Assassinations (HSCA), and the release of pertinent documents as a result of the Kennedy Assassination Records Collection Act, an image of an unconvinced public is seen. Evidence of this can be seen not only in the number of cultural and literary endeavors dedicated to the topic, but also by the public’s insatiable appetite for said material. By examining literature both critical of and in support of the Warren Report, documents collected by the Assassination Records Review Board (ARRB), and the public’s response expressed through the arts, indicates an ongoing culture of disbelief in the findings of the Warren Report. Polling data suggests that the Warren Report was not only ill received, but as additional information became public, the work of the Commission also became less reliable according to public opinion. This occurred despite of the efforts of traditional media outlets to not only marginalize critics, but also to weaponize the term “conspiracy theorist” as a pejorative. In the eyes of the public, a congressional committee reaching this conclusion not only acerbated their disbelief in the Warren Report, but also indicated that federal agencies had practiced an ongoing campaign of deception. As an expression of the Warren Report’s lack of credence is its ongoing debate through art. Manifesting itself in the form of literature, plays, film, television, song; the Warren Report’s selective use of testimony, missing evidence, and its rush to assure the public that Oswald was the lone-gunman had failed

Impact of China's Accession to the WTO on U.S. Agricultural Exports

China's accession to the WTO has been welcomed by a broad range of U.S. agricultural interests. The WTO agreement will lower tariffs and other barriers, and increase market access, but the actual benefits to U.S. exporters will depend on the competitiveness of U.S. exports with those of other countries and on China's implementation of WTO rules. Analysis by the U.S. Department of Agriculture indicates immediate gains in export sales for U.S. agriculture, gains that will increase over time as market access expands and as Chinese economic growth boosts demand for imported agricultural products. However, some observers express less optimism, indicating that while U.S. exports to China should expand "in theory," in practice exporters will face several hurdles which must be overcome in order to reach the full potential of the Chinese market. This paper adds to USDA and other analyses of China's export potential by discussing the status of China's WTO implementation for agriculture, and provides a qualitative assessment of the potential for U.S. agricultural exports to China over the next few years.International Relations/Trade,

Cosmological structure formation from soft topological defects

Some models have extremely low-mass pseudo-Goldstone bosons that can lead to vacuum phase transitions at late times, after the decoupling of the microwave background.. This can generate structure formation at redshifts z greater than or approx 10 on mass scales as large as M approx 10 to the 18th solar masses. Such low energy transitions can lead to large but phenomenologically acceptable density inhomogeneities in soft topological defects (e.g., domain walls) with minimal variations in the microwave anisotropy, as small as delta Y/T less than or approx 10 to the minus 6 power. This mechanism is independent of the existence of hot, cold, or baryonic dark matter. It is a novel alternative to both cosmic string and to inflationary quantum fluctuations as the origin of structure in the Universe

Vocal Classification of Vocalizations of a Pair of Asian Small-Clawed Otters to Determine Stress

Asian Small-Clawed Otters (Aonyx cinerea) are a small, protected but threatened species living in freshwater. They are gregarious and live in monogamous pairs for their lifetimes, communicating via scent and acoustic vocalizations. This study utilized a hidden Markov model (HMM) to classify stress versus non-stress calls from a sibling pair under professional care. Vocalizations were expertly annotated by keepers into seven contextual categories. Four of these—aggression, separation anxiety, pain, and prefeeding—were identified as stressful contexts, and three of them—feeding, training, and play—were identified as non-stressful contexts. The vocalizations were segmented, manually categorized into broad vocal type call types, and analyzed to determine signal to noise ratios. From this information, vocalizations from the most common contextual categories were used to implement HMM-based automatic classification experiments, which included individual identification, stress vs non-stress, and individual context classification. Results indicate that both individual identity and stress vs non-stress were distinguishable, with accuracies above 90%, but that individual contexts within the stress category were not easily separable

QED in strong, finite-flux magnetic fields

Lower bounds are placed on the fermionic determinants of Euclidean quantum electrodynamics in two and four dimensions in the presence of a smooth, finite-flux, static, unidirectional magnetic field $B(r) =(0,0,B(r))$, where $B(r) \geq 0$ or $B(r) \leq 0$, and $r$ is a point in the xy-plane.Comment: 10 pages, postscript (in uuencoded compressed tar file

Transverse field-induced nucleation pad switching modes during domain wall injection

We have used magnetic transmission soft X-ray microscopy (M-TXM) to image in-field magnetization configurations of patterned Ni80F20 domain wall "nucleation pads" with attached planar nanowires. Comparison with micromagnetic simulations suggests that the evolution of magnetic domains in rectangular injection pads depends on the relative orientation of closure domains in the remanent state. The magnetization reversal pathway is altered by the inclusion of transverse magnetic fields. These different modes explain previous results of domain wall injection into nanowires

Speculative bubbles in Bitcoin markets? An empirical investigation into the fundamental value of Bitcoin

Amid its rapidly increasing usage and immense public interest the subject of Bitcoin has raised profound economic and societal issues. In this paper we undertake economic and econometric modelling of Bitcoin prices. As with many asset classes we show that Bitcoin exhibits speculative bubbles. Further, we find empirical evidence that the fundamental price of Bitcoin is zero