A low-loss wideband suspended coaxial transmission line\ud

This paper presents a transmission-line structure suitable \ud for micromachining technology. The structure is an air-filled square coaxial cable, which is very low loss and has been designed in order to utilise current manufacturing processes. This transmission line demonstrates that such a structure can be designed to cover very wide bandwidth. \ud As the cable is air filled, the centre conductor needs to be supported and this is accomplished by attaching quarter-wavelength stubs to the ground. The design method of such a cable is presented in detail and the results of an X-band component are presented

Quantal interferometry with dissipative internal motion

In presence of dissipation, quantal states may acquire complex-valued phase effects. We suggest a notion of dissipative interferometry that accommodates this complex-valued structure and that may serve as a tool for analyzing the effect of certain kinds of external influences on quantal interference. The concept of mixed-state phase and concomitant gauge invariance is extended to dissipative internal motion. The resulting complex-valued mixed-state interference effects lead to well-known results in the unitary limit and in the case of dissipative motion of pure quantal states. Dissipative interferometry is applied to fault-tolerant geometric quantum computation.Comment: Slight revision, journal reference adde

Anharmonic effect on lattice distortion, orbital ordering and magnetic properties in Cs2AgF4

We develop the cluster self-consistent field method incorporating both electronic and lattice degrees of freedom to study the origin of ferromagnetism in Cs$_{2}$AgF$_{4}$. After self-consistently determining the harmonic and anharmonic Jahn-Teller distortions, we show that the anharmonic distortion stabilizes the staggered x$^{2}$-z$^{2}$/y$^{2}$-z$^{2}$ orbital and ferromagnetic ground state, rather than the antiferromagnetic one. The amplitudes of lattice distortions, Q$_{2}$ and Q$_{3}$, the magnetic coupling strengthes, J$_{x,y}$, and the magnetic moment, are in good agreement with the experimental observation.Comment: 13 pages, 5 figure

Two-dimensional magnetism in the pnictide superconductor parent material SrFeAsF probed by muon-spin relaxation

We report muon-spin relaxation measurements on SrFeAsF, which is the parent compound of a newly discovered iron-arsenic-fluoride based series of superconducting materials. We find that this material has very similar magnetic properties to LaFeAsO, such as separated magnetic and structural transitions (TN = 120 K, Ts = 175 K), contrasting with SrFe2As2 where they are coincident. The muon oscillation frequencies fall away very sharply at TN, which suggests that the magnetic exchange between the layers is weaker than in comparable oxypnictide compounds. This is consistent with our specific heat measurements, which find that the entropy change S = 0.05 J/mol/K largely occurs at the structural transition and there is no anomaly at TN.Comment: 4 pages, 3 figure

Interview with Ralph Lancaster by Mike Hastings

Biographical NoteRalph I. Lancaster, Jr. was born on May 5, 1930, in Bangor, Maine, to Ralph I. Lancaster, Sr. and Mary Kelleher Lancaster. He was reared in Bangor by Bridget and Charles Mylan. He attended high school at John Bapst and went on to the College of the Holy Cross in Worcester, Massachusetts, being graduated in 1952 with a degree in English and a minor in history. He earned his law degree from Harvard Law School, then was drafted and spent two years in the Army. He returned to Maine to clerk for Judge Gignoux and remained in that position for two years. Then he was offered a position at the law firm Hutchinson Pierce, where he remained at the time of this interview (now Pierce Atwood) as a trial lawyer. SummaryInterview includes discussion of: growing up in Bangor; Holy Cross and Harvard Law School; Lancaster’s experience in the Army; clerkship with Judge Gignoux; the University of Maine Law School and the overabundance of lawyers in parts of Maine; how Lancaster came to work for Hutchinson Pierce (now Pierce Atwood); being a trial lawyer and a Maine lawyer; how Judge Gignoux was selected, his attributes, and occasions when he would sit in other locations around the country; George Mitchell’s appointment to the federal judgeship in Maine; Lancaster’s reaction to Mitchell’s appointment to Muskie’s U.S. Senate seat; Supreme Court consideration; how the practice of law has changed in Maine; the degree to which education prepares a lawyer for his or her work and the need for hands-on experience; and Lancaster’s views on lawyers advertising

Performance of RF MEMS switches at low temperatures

The actuation voltage of microelectromechanical system (MEMS) \ud metal switches was investigated at temperatures ranging from 10 to 290 K. The investigation shows a 50% increase in the actuation voltage at low temperature. A comparison has been made using a published model and showed similar increment of actuation voltage at low temperature

Table & seed potatoes from Western Australia at a glance

Western Australia is a leading national exporter of table potatoes, accounting for almost 40 per cent of Australian exports. The high quality of Western Australian potatoes commands premium prices on both national and international markets. Opportunities to export Certified potato seed, particularly to south east Asian markets are growing and varieties suited to export markets are being developed.https://researchlibrary.agric.wa.gov.au/bulletins/1077/thumbnail.jp

Application of Bayesian Principles to the Evaluation of Coronary Artery Disease in the Modern Era

The number of testing modalities available for the diagnosis of significant coronary artery disease has grown over the last few decades. Inappropriate utilization of these tests often leads to: (i) further investigation, (ii) physician and patient uncertainty, (iii) harm and poor outcomes, and (iv) increase in health care costs. An informed approach to the evaluation of the patients with stable ischemic chest pain can lead to efficient use of resources and better outcomes. Throughout the course of this chapter, we will explain how the applications of age-old statistical principles are still relevant in this modern era of technological advancement

Wireless recording of the calls of Rousettus aegyptiacus and their reproduction using electrostatic transducers

Bats are capable of imaging their surroundings in great detail using echolocation. To apply similar methods to human engineering systems requires the capability to measure and recreate the signals used, and to understand the processing applied to returning echoes. In this work, the emitted and reflected echolocation signals of Rousettus aegyptiacus are recorded while the bat is in flight, using a wireless sensor mounted on the bat. The sensor is designed to replicate the acoustic gain control which bats are known to use, applying a gain to returning echoes that is dependent on the incurred time delay. Employing this technique allows emitted and reflected echolocation calls, which have a wide dynamic range, to be recorded. The recorded echoes demonstrate the complexity of environment reconstruction using echolocation. The sensor is also used to make accurate recordings of the emitted calls, and these calls are recreated in the laboratory using custom-built wideband electrostatic transducers, allied with a spectral equalization technique. This technique is further demonstrated by recreating multi-harmonic bioinspired FM chirps. The ability to record and accurately synthesize echolocation calls enables the exploitation of biological signals in human engineering systems for sonar, materials characterization and imaging

Preliminary evidence for genetic overlap between body mass index and striatal reward response

The reward-processing network is implicated in the aetiology of obesity. Several lines of evidence suggest obesitylinked genetic risk loci (such as DRD2 and FTO) may influence individual variation in body mass index (BMI) through neuropsychological processes reflected in alterations in activation of the striatum during reward processing. However, no study has tested the broader hypotheses that (a) the relationship between BMI and reward-related brain activation (measured through the blood oxygenation-dependent (BOLD) signal) may be observed in a large population study and (b) the overall genetic architecture of these phenotypes overlap, an assumption critical for the progression of imaging genetic studies in obesity research. Using data from the Human Connectome Project (N = 1055 healthy, young individuals: average BMI = 26.4), we first establish a phenotypic relationship between BMI and ventral striatal (VS) BOLD during the processing of rewarding (monetary) stimuli (β = 0.44, P = 0.013), accounting for potential confounds. BMI and VS BOLD were both significantly influenced by additive genetic factors (H2r = 0.57; 0.12, respectively). Further decomposition of this variance suggested that the relationship was driven by shared genetic (ρg = 0.47, P = 0.011), but not environmental (ρE = −0.07, P = 0.29) factors. To validate the assumption of genetic pleiotropy between BMI and VS BOLD, we further show that polygenic risk for higher BMI is also associated with increased VS BOLD response to appetitive stimuli (calorically high food images), in an independent sample (N = 81; PFWE−ROI o 0.005). Together, these observations suggest that the genetic factors link risk to obesity to alterations within key nodes of the brain's reward circuity. These observations provide a basis for future work exploring the mechanistic role of genetic loci that confer risk for obesity using the imaging genetics approach