Aerothermodynamic Assessment of Corrugated Panel Thermal Protection Systems

The feasibility of using corrugated panels as a thermal protection system for an advanced space transportation vehicle was investigated. The study consisted of two major tasks: development of improved correlations for wind tunnel heat transfer and pressure data to yield design techniques, and application of the design techniques to determine if corrugated panels have application future aerospace vehicles. A single-stage-to-orbit vehicle was used to assess advantages and aerothermodynamic penalties associated with use of such panels. In the correlation task, experimental turbulent heat transfer and pressure data obtained on corrugation roughened surfaces during wind tunnel testing were analyzed and compared with flat plate data. The correlations and data comparisons included the effects of a large range of geometric, inviscid flow, internal boundary layer, and bulk boundary layer parameters in supersonic and hypersonic flow

The Surgical Nosology In Primary-care Settings (SNIPS): a simple bridging classification for the interface between primary and specialist care

BACKGROUND: The interface between primary care and specialist medical services is an important domain for health services research and policy. Of particular concern is optimising specialist services and the organisation of the specialist workforce to meet the needs and demands for specialist care, particularly those generated by referral from primary care. However, differences in the disease classification and reporting of the work of primary and specialist surgical sectors hamper such research. This paper describes the development of a bridging classification for use in the study of potential surgical problems in primary care settings, and for classifying referrals to surgical specialties. METHODS: A three stage process was undertaken, which involved: (1) defining the categories of surgical disorders from a specialist perspective that were relevant to the specialist-primary care interface; (2) classifying the 'terms' in the International Classification of Primary Care Version 2-Plus (ICPC-2 Plus) to the surgical categories; and (3) using referral data from 303,000 patient encounters in the BEACH study of general practice activity in Australia to define a core set of surgical conditions. Inclusion of terms was based on the probability of specialist referral of patients with such problems, and specialists' perception that they constitute part of normal surgical practice. RESULTS: A four-level hierarchy was developed, containing 8, 27 and 79 categories in the first, second and third levels, respectively. These categories classified 2050 ICPC-2 Plus terms that constituted the fourth level, and which covered the spectrum of problems that were managed in primary care and referred to surgical specialists. CONCLUSION: Our method of classifying terms from a primary care classification system to categories delineated by specialists should be applicable to research addressing the interface between primary and specialist care. By describing the process and putting the bridging classification system in the public domain, we invite comment and application in other settings where similar problems might be faced

S = 3 Ground State for a Tetranuclear Mn^(IV)₄O₄ Complex Mimicking the S₃ State of the Oxygen Evolving Complex

The S₃ state is currently the last observable intermediate prior to O–O bond formation at the oxygen-evolving complex (OEC) of Photosystem II, and its electronic structure has been assigned to a homovalent Mn^(IV)₄ core with an S = 3 ground state. While structural interpretations based on the EPR spectroscopic features of the S₃ state provide valuable mechanistic insight, corresponding synthetic and spectroscopic studies on tetranuclear complexes mirroring the Mn oxidation states of the S₃ state remain rare. Herein, we report the synthesis and characterization by XAS and multifrequency EPR spectroscopy of a Mn^(IV)₄O₄ cuboidal complex as a spectroscopic model of the S₃ state. Results show that this Mn^(IV)₄O₄ complex has an S = 3 ground state with isotropic ⁵⁵Mn hyperfine coupling constants of −75, −88, −91, and 66 MHz. These parameters are consistent with an αααβ spin topology approaching the trimer–monomer magnetic coupling model of pseudo-octahedral Mn^(IV) centers. Importantly, the spin ground state changes from S = 1/2 to S = 3 as the OEC is oxidized from the S₂ state to the S₃ state. This same spin state change is observed following oxidation of the previously reported Mn^(III)Mn^(IV)₃O₄ cuboidal complex to the Mn^(IV)₄O₄ complex described here. This sets a synthetic precedent for the observed low-spin to high-spin conversion in the OEC

HD 145263: Spectral Observations of Silica Debris Disk Formation via Extreme Space Weathering?

We report here time domain infrared spectroscopy and optical photometry of the HD145263 silica-rich circumstellar disk system taken from 2003 through 2014. We find an F4V host star surrounded by a stable, massive 1e22 - 1e23 kg (M_Moon to M_Mars) dust disk. No disk gas was detected, and the primary star was seen rotating with a rapid ~1.75 day period. After resolving a problem with previously reported observations, we find the silica, Mg-olivine, and Fe-pyroxene mineralogy of the dust disk to be stable throughout, and very unusual compared to the ferromagnesian silicates typically found in primordial and debris disks. By comparison with mid-infrared spectral features of primitive solar system dust, we explore the possibility that HD 145263's circumstellar dust mineralogy occurred with preferential destruction of Fe-bearing olivines, metal sulfides, and water ice in an initially comet-like mineral mix and their replacement by Fe-bearing pyroxenes, amorphous pyroxene, and silica. We reject models based on vaporizing optical stellar megaflares, aqueous alteration, or giant hypervelocity impacts as unable to produce the observed mineralogy. Scenarios involving unusually high Si abundances are at odds with the normal stellar absorption near-infrared feature strengths for Mg, Fe, and Si. Models involving intense space weathering of a thin surface patina via moderate (T < 1300 K) heating and energetic ion sputtering due to a stellar superflare from the F4V primary are consistent with the observations. The space weathered patina should be reddened, contain copious amounts of nanophase Fe, and should be transient on timescales of decades unless replenished.Comment: 41 Pages, 5 Figures, 5 Tables, Accepted for publication in the Astrophysical Journa

Systematics of Fission Barriers in Superheavy Elements

We investigate the systematics of fission barriers in superheavy elements in the range Z = 108-120 and N = 166-182. Results from two self-consistent models for nuclear structure, the relativistic mean-field (RMF) model as well as the non-relativistic Skyrme-Hartree-Fock approach are compared and discussed. We restrict ourselves to axially symmetric shapes, which provides an upper bound on static fission barriers. We benchmark the predictive power of the models examining the barriers and fission isomers of selected heavy actinide nuclei for which data are available. For both actinides and superheavy nuclei, the RMF model systematically predicts lower barriers than most Skyrme interactions. In particular the fission isomers are predicted too low by the RMF, which casts some doubt on recent predictions about superdeformed ground states of some superheavy nuclei. For the superheavy nuclei under investigation, fission barriers drop to small values around Z = 110, N = 180 and increase again for heavier systems. For most of the forces, there is no fission isomer for superheavy nuclei, as superdeformed states are in most cases found to be unstable with respect to octupole distortions.Comment: 17 pages REVTEX, 12 embedded eps figures. corrected abstrac

Structural Effects of Ammonia Binding to the Mn_4CaO_5 Cluster of Photosystem II

The Mn_4CaO_5 oxygen-evolving complex (OEC) of photosystem II catalyzes the light-driven oxidation of two substrate waters to molecular oxygen. ELDOR-detected NMR along with computational studies indicated that ammonia, a substrate analogue, binds as a terminal ligand to the Mn4A ion trans to the O5 μ_4 oxido bridge. Results from electron spin echo envelope modulation (ESEEM) spectroscopy confirmed this and showed that ammonia hydrogen bonds to the carboxylate side chain of D1-Asp61. Here we further probe the environment of OEC with an emphasis on the proximity of exchangeable protons, comparing ammonia-bound and unbound forms. Our ESEEM and electron nuclear double resonance (ENDOR) results indicate that ammonia substitutes for the W1 terminal water ligand without significantly altering the electronic structure of the OEC

Novel heavy-traffic regimes for large-scale service systems

We introduce a family of heavy-traffic regimes for large scale service systems, presenting a range of scalings that include both moderate and extreme heavy traffic, as compared to classical heavy traffic. The heavy-traffic regimes can be translated into capacity sizing rules that lead to Economies-of-Scales, so that the system utilization approaches 100% while congestion remains limited. We obtain heavy-traffic approximations for stationary performance measures in terms of asymptotic expansions, using a non-standard saddle point method, tailored to the specific form of integral expressions for the performance measures, in combination with the heavy-traffic regimes

Respiratory tract infections among children younger than 5 years: Current management in Australian general practice

Objective: To explore the current management in Australian general practice of common respiratory tract infections (RTIs) in children younger than 5 years. Design, setting and participants: Analysis of data from a sample of 4522 general practitioners who participated in the Bettering the Evaluation and Care of Health (BEACH) cross-sectional survey, April 2007 to March 2012. Consultations with children younger than 5 years were analysed. Main outcome measures: GPs’ management of four common RTIs (acute upper RTI [URTI], acute bronchitis/bronchiolitis, acute tonsillitis, and pneumonia) in association with six management options: antibiotic medications; prescribed or supplied non-antibiotic medications; medications advised for over-the-counter purchase; referrals; pathology testing; and counselling. Results: Of 31 295 encounters recorded, at least one of the four selected paediatric RTIs was managed at 8157 encounters. URTI was managed 18.6 times per 100 GP patient encounters, bronchitis/bronchiolitis 4.2 times, acute tonsillitis 2.7 times, and pneumonia 0.6 times per 100 encounters. Antibiotics were prescribed most frequently for tonsillitis and least frequently for URTI. Male GPs prescribed antibiotics for URTI significantly more often than female GPs, while older GPs prescribed antibiotics for URTI more often than younger GPs. Conclusion: GP management of paediatric RTIs in Australia varied according to the clinical problem and with age and sex of the GP. Further research into parents’ and health professionals’ attitudes and practices regarding the role of antibiotics, over-the-counter medications, and hygiene will help maintain favourable management practices

A dynamical model of surrogate reactions

A new dynamical model is developed to describe the whole process of surrogate reactions; transfer of several nucleons at an initial stage, thermal equilibration of residues leading to washing out of shell effects and decay of populated compound nuclei are treated in a unified framework. Multi-dimensional Langevin equations are employed to describe time-evolution of collective coordinates with a time-dependent potential energy surface corresponding to different stages of surrogate reactions. The new model is capable of calculating spin distributions of the compound nuclei, one of the most important quantity in the surrogate technique. Furthermore, various observables of surrogate reactions can be calculated, e.g., energy and angular distribution of ejectile, and mass distributions of fission fragments. These features are important to assess validity of the proposed model itself, to understand mechanisms of the surrogate reactions and to determine unknown parameters of the model. It is found that spin distributions of compound nuclei produced in $^{18}$O+$^{238}$U $\rightarrow ^{16}$O+$^{240*}$U and $^{18}$O+$^{236}$U $\rightarrow ^{16}$O+$^{238*}$U reactions are equivalent and much less than 10$\hbar$, therefore satisfy conditions proposed by Chiba and Iwamoto (PRC 81, 044604(2010)) if they are used as a pair in the surrogate ratio method.Comment: 17 pages, 5 figure

Emergency contraception in Australia: The desired source of information versus the actual source of information

Objective: To determine long-term trends in emergency contraception (EC) management by general practitioners in Australia. Design, setting and participants: Data from April 2000 to March 2012 were drawn from the BEACH (Bettering the Evaluation and Care of Health) program, a continuous cross-sectional survey of GP activity. We analysed consultations involving EC management, unwanted pregnancy management and emergency contraceptive pill (ECP) prescribing per 1000 GP encounters with women aged 14-54 years. Summary statistics were calculated with 95% confidence intervals. Results: In 2000-2001, GPs managed EC problems at a rate of 5.50 per 1000 encounters (95% CI, 4.37-6.63). From 2004, after the ECP became available over the counter (OTC) in pharmacies, EC management, which includes ECP prescription, progressively declined. By 2011-2012, only 1.43 EC problems were managed per 1000 encounters (95% CI, 0.84-2.02) and only 0.48 ECP prescriptions were provided per 1000 encounters (95% CI, 0.14-0.82). Yet the management rate of unwanted pregnancy problems stayed relatively constant (rate in 2000-2001, 0.95 per 1000 encounters; 95% CI, 0.40-1.50; rate in 2011-2012, 0.88 per 1000 encounters; 95% CI, 0.41-1.36). Conclusion: Low rates of EC management by GPs since ECP became available OTC suggest that women may be obtaining information on EC elsewhere. Further investigation is needed to uncover the sources of this information and its acceptability and application by Australian women