Reactive ion etching of tellurite and chalcogenide waveguides using hydrogen, methane, and argon

The authors report in detail on the reactive plasma etching properties of tellurium and demonstrate a high quality etching process using hydrogen, methane, and argon. Very low loss planar ridge waveguides are demonstrated. Optical losses in tellurium dioxide waveguides below 0.1 dB/cm in most of the near infrared region of the electromagnetic spectrum and at 1550 nm have been achieved—the lowest ever reported by more than an order of magnitude and clearly suitable for planar integrated devices. The etch process is also shown to be suitable for chalcogenide glasses which may be of importance in applications such as phase change memory devices and nonlinear integrated optics.The support of the Australian Research Council through its Discovery Grant Program is gratefully acknowledged Grant No. DP070333

The Decomposition Theorem For Two-Dimensional Shifts Of Finite Type

A one-dimensional shift of finite type can be described as the collection of bi-infinite walks along an edge graph. The Decomposition Theorem states that every conjugacy between two shifts of finite type can be broken down into a finite sequence of splittings and amalgamations of their edge graphs. When dealing with two-dimensional shifts of finite type, the appropriate edge graph description is not as clear; we turn to Nasu\u27s notion of a textile system for such a description and show that all two-dimensional shifts of finite type can be so described. We then define textile splittings and amalgamations and prove that every conjugacy between two-dimensional shifts of finite type can be broken down into a finite sequence of textile splittings, textile amalgamations, and a third operation called an inversion

Putting The Pieces Together: Understanding Robinson’s Nonperiodic Tilings

A discussion of Robinson\u27s nonperiodic tilings and nonperiodic tilings with nonsquare tiles (Penrose and pinwheel)

Renewal Systems, Sharp-Eyed Snakes, And Shifts Of Finite Type

Johnson and Madden look at collections of bi-infinite strings of symbols that occur in several different areas of mathematics and ask whether these collections are the same in some sense. A dynamical systems property called entropy can be used to show that the shifts of finite type are not all conjugate to uniquely decipherable renewal systems

Projectional Entropy In Higher Dimensional Shifts Of Finite Type

Any higher dimensional shift space (X, ℤᵈ) contains many lower dimensional shift spaces obtained by projection onto r-dimensional sublattices L of ℤᵈ where r \u3c d. We show here that any projectional entropy is bounded below by the ℤᵈ entropy and, in the case of certain shifts of finite type satisfying a mixing condition, equality is achieved if and only if the shift of finite type is the infinite product of a lower dimensional projection

Patient perspectives on discussing alcohol as part of medicines review in community pharmacies.

BACKGROUND: This paper reports on a qualitative study which formed part of the intervention development phase of a five year research programme (Community pharmacy: Highlighting Alcohol use in Medication aPpointments; CHAMP-1). OBJECTIVES: To better understand patient views on the appropriateness of alcohol as a subject for discussion in medication reviews in community pharmacy. METHODS: Semi-structured interviews were conducted with a sample of 25 people eligible for medication reviews whose AUDIT-C screening scores identified them as likely risky drinkers. Transcripts were analysed using a modified framework method with a constructionist thematic analysis approach. RESULTS: Most patients interviewed said they were open to the idea of a medication and alcohol linked discussion with a pharmacist if this was routine, well-conducted and confidential. Such a discussion was thought less personally relevant for those who viewed the proposed intervention through the prism of a particular set of ideas about the nature of alcohol problems, which distanced them from thinking about alcohol in terms of their everyday life and possible impacts on their health. Study findings attest to some of the sensitivities involved in discussion of alcohol, and the complexities inherent in helping people to talk about their own drinking, medicine use and health. CONCLUSIONS: Patients were open to the idea of discussing alcohol with community pharmacists in the context of a medicines review if this was sensitively done and the relevance was clear to them

Star-forming dwarf galaxies in the Virgo cluster: the link between molecular gas, atomic gas, and dust

We present $^{12}$CO(1-0) and $^{12}$CO(2-1) observations of a sample of 20 star-forming dwarfs selected from the Herschel Virgo Cluster Survey, with oxygen abundances ranging from 12 + log(O/H) ~ 8.1 to 8.8. CO emission is observed in ten galaxies and marginally detected in another one. CO fluxes correlate with the FIR 250 $\mu$m emission, and the dwarfs follow the same linear relation that holds for more massive spiral galaxies extended to a wider dynamical range. We compare different methods to estimate H2 molecular masses, namely a metallicity-dependent CO-to-H2 conversion factor and one dependent on H-band luminosity. The molecular-to-stellar mass ratio remains nearly constant at stellar masses <~ 10$^9$ M$_{\odot}$, contrary to the atomic hydrogen fraction, M$_{HI}$/M$_*$, which increases inversely with M$_*$. The flattening of the M$_{H_2}$/M$_*$ ratio at low stellar masses does not seem to be related to the effects of the cluster environment because it occurs for both HI-deficient and HI-normal dwarfs. The molecular-to-atomic ratio is more tightly correlated with stellar surface density than metallicity, confirming that the interstellar gas pressure plays a key role in determining the balance between the two gaseous components of the interstellar medium. Virgo dwarfs follow the same linear trend between molecular gas mass and star formation rate as more massive spirals, but gas depletion timescales, $\tau_{dep}$, are not constant and range between 100 Myr and 6 Gyr. The interaction with the Virgo cluster environment is removing the atomic gas and dust components of the dwarfs, but the molecular gas appears to be less affected at the current stage of evolution within the cluster. However, the correlation between HI deficiency and the molecular gas depletion time suggests that the lack of gas replenishment from the outer regions of the disc is lowering the star formation activity.Comment: 19 pages, 11 figures, accepted for publication in Astronomy & Astrophysic

Distributed top-k aggregation queries at large

Top-k query processing is a fundamental building block for efficient ranking in a large number of applications. Efficiency is a central issue, especially for distributed settings, when the data is spread across different nodes in a network. This paper introduces novel optimization methods for top-k aggregation queries in such distributed environments. The optimizations can be applied to all algorithms that fall into the frameworks of the prior TPUT and KLEE methods. The optimizations address three degrees of freedom: 1) hierarchically grouping input lists into top-k operator trees and optimizing the tree structure, 2) computing data-adaptive scan depths for different input sources, and 3) data-adaptive sampling of a small subset of input sources in scenarios with hundreds or thousands of query-relevant network nodes. All optimizations are based on a statistical cost model that utilizes local synopses, e.g., in the form of histograms, efficiently computed convolutions, and estimators based on order statistics. The paper presents comprehensive experiments, with three different real-life datasets and using the ns-2 network simulator for a packet-level simulation of a large Internet-style network

Using qualitative process evaluation in the development of a complex intervention to advance person-centred practice by pharmacists: The Medicines and Alcohol Consultation (MAC)

In order to effectively evaluate complex interventions, there have been calls for the further integration of qualitative methods. Qualitative process studies of brief alcohol interventions and medicines reviews are notably lacking. This article provides a grounded example through the presentation of findings from an embedded qualitative process evaluation of a multi-site, pilot cluster RCT of a new intervention: the Medicines and Alcohol Consultation (MAC). MAC is designed to increase the capacity of community pharmacists (CPs) to conduct person-centred medicines reviews in which the subject of alcohol consumption is raised in connection with medications and associated health conditions. Participant-focused qualitative studies (interviews, observations, recorded consultations) sought to understand how CPs engaged with and implemented MAC in context. This article documents effects of the intervention on developing person-centred consultation practice and highlights how qualitative process studies can be used formatively to develop middle range programme theory and to optimise intervention design for testing in a definitive RCT