Micas in experimentally shocked gneiss

Biotites and muscovites from a gneiss have been experimentally shocked between 18 and 70 GPa using powder-propellant guns at NASA Johnson Space Center and at the California Institute of Technology. This study shows that shock in biotite and muscovite can produce homogeneous and devolatilized glasses within microseconds. Shock-deformed micas display fracturing, kinking, and complex extinction patterns over the entire pressure range investigated. However, these deformation features are not a sensitive pressure indicator. Localized melting of micas begins at 33 GPa and goes to completion at 70 GPa. Melted biotite and muscovite are optically opaque, but show extensive microvesiculation and flow when observed with the SEM. Electron diffraction confirms that biotite and muscovite have transformed to a glass. The distribution of vesicles in shock-vitrified mica shows escape of volatiles within the short duration of the shock experiment. Experimentally shocked biotite and muscovite undergo congruent melting. Compositions of the glasses are similar to the unshocked micas except for volatiles (H2O loss and K loss). These unusual glasses derived from mica may be quenched by rapid cooling conditions during the shock experiment. Based on these results, the extremely low H2O content of tektites may be reconciled with a terrestrial origin by impact. Release of volatiles in shock-melted micas affects the melting behavior of coexisting dry silicates during the short duration of the shock experiment. Transportation and escape of volatiles released from shock-melted micas may provide plausible mechanisms for the origin of protoatmospheres on terrestrial planets, hydrothermal activity on phyllosilicate-rich meteorite parent bodies, and fluid entrapment in meteorites.

Melting, ablation, and vapor phase condensation during atmospheric passage of the Bjurbole Meteorite

A detailed study of the Bjurbole fusion crust using scanning electron microscopy (SEM) and energy dispersive analysis (EDS) shows that filamentary crystals and ablation spheres may form on the meteoroid surface. Filamentary crystals, hollow spheres, and porous regions of the surface point to a period of intense vapor phase activity during atmospheric passage. Filamentary crystals can be divided into three categories on the basis of bulk composition and morphology. Two types of filamentary crystals are vapor phase condensation products formed during atmospheric entry of the meteoroid. The other type forms by the interaction of seawater with the fusion surface. The density and composition of ablation spheres varies with the flight orientation of the meteorite. The size range and composition of iron-nickel spheres on the surface of Bjurbole are similar to spheres collected in the stratosphere. A comparison of stratospheric dust collections with meteorite surfaces may provide further insight into the mechanisms of meteoroid entry into planetary atmospheres.

Minimum important difference between patients with rheumatoid arthritis : the patient's perspective

OBJECTIVE: To determine the point at which differences in clinical assessment scores on physical ability, pain and overall condition are sufficiently large to correspond to a subjective perception of a meaningful difference from the perspective of the patient. METHODS: Forty patients with a diagnosis of rheumatoid arthritis participated in an evening of clinical assessment and one-on-one conversations with each other regarding their arthritic condition. The assessments included tender and swollen joint counts, clinician and patient global assessments, participant assessment of pain and the Health Assessment Questionnaire (HAQ) on physical ability. After each conversation, participants rated themselves relative to their conversational partner on physical ability, pain and overall condition. These subjective comparative ratings were compared to the differences of the individual clinical assessments. RESULTS: In total there were 120 conversations. Generally participants judged themselves as less disabled than others. They rated themselves as "somewhat better" than their conversation partner when they had a (mean) 7% better score on the HAQ, 6% less pain, and 9% better global assessment. In contrast, they rated themselves as "somewhat worse" when they had a (mean) 16% worse score on the HAQ, 16% more pain, and 29% worse global assessment. CONCLUSIONS: Patients view clinically important differences in an asymmetric manner. These results can provide guidance in interpreting results and planning clinical trials.

(Mis)Using Pulse Oximetry : A Review of Pulse Oximetry use in Acute Care Medical Wards

Background: Nurses routinely use pulse oximetry (SpO2) monitoring equipment in acute care. Interpretation of the reading involves physical assessment and awareness of parameters including temperature, haemoglobin, and peripheral perfusion. However, there is little information on whether these clinical signs are routinely measured or used in pulse oximetry interpretation by nurses. Aim: The aim of this study was to review current practice of SpO2 measurement and the associated documentation of the physiological data that is required for accurate interpretation of the readings. The study reviewed the documentation practices relevant to SpO2 in five medical wards of a tertiary level metropolitan hospital. Method: A prospective casenote audit was conducted on random days over a three-month period. The audit tool had been validated in a previous study. Results: One hundred and seventy seven episodes of oxygen saturation monitoring were reviewed. Our study revealed a lack of parameters to validate the SpO2 readings. Only 10% of the casenotes reviewed had sufficient physiological data to meaningfully interpret the SpO2 reading and only 38% had an arterial blood gas as a comparator. Nursing notes rarely documented clinical interpretation of the results. Conclusion: The audits suggest that medical and nursing staff are not interpreting the pulse oximetry results in context and that the majority of the results were normal with no clinical indication for performing this observation. This reduces the usefulness of such readings and questions the appropriateness of performing “routine” SpO2 in this context.

Supporting risk-informed decisions during business process execution

This paper proposes a technique that supports process participants in making risk-informed decisions, with the aim to reduce the process risks. Risk reduction involves decreasing the likelihood and severity of a process fault from occurring. Given a process exposed to risks, e.g. a financial process exposed to a risk of reputation loss, we enact this process and whenever a process participant needs to provide input to the process, e.g. by selecting the next task to execute or by filling out a form, we prompt the participant with the expected risk that a given fault will occur given the particular input. These risks are predicted by traversing decision trees generated from the logs of past process executions and considering process data, involved resources, task durations and contextual information like task frequencies. The approach has been implemented in the YAWL system and its effectiveness evaluated. The results show that the process instances executed in the tests complete with substantially fewer faults and with lower fault severities, when taking into account the recommendations provided by our technique.

Proportionality of sanctions under the WADA Code : CAS jurisprudence and the need for a strict approach

This article suggests that the issue of proportionality in anti-doping sanctions has been inconsistently dealt with by the Court of Arbitration for Sport (CAS). Given CAS’s pre-eminent role in interpreting and applying the World Anti-Doping Code under the anti-doping policies of its signatories, an inconsistent approach to the application of the proportionality principle will cause difficulties for domestic anti-doping tribunals seeking guidance as to the appropriateness of their doping sanctions.

Contract Law Case Book [2nd ed.]

This case book contains the essential sections of the most significant cases in Australian contract law. Ready access to this collection of cases enables students to experience the law through the judges’ own words, and to develop the skills of interpreting and analysing cases in order to refine their understanding of the law. Excerpts from important statutes and writings are also included.

Intratherapist reliability in the rating of scapula posture in multiple planes of reference

Background: Evaluation of scapular posture is a fundamental component in the clinical evaluation of the upper quadrant. This study examined the intrarater reliability of scapular posture ratings. Methods: A test-retest reliability investigation was undertaken with one week between assessment sessions. At each session physical therapists conducted visual assessments of scapula posture (relative to the thorax) in five different scapula postural planes (plane of scapula, sagittal plane, transverse plane, horizontal plane, and vertical plane). These five plane ratings were performed for four different scapular posture perturbating conditions (rest, isometric shoulder; flexion, abduction, and external rotation). Results. A total of 100 complete scapular posture ratings (50 left, 50 right) were undertaken at each assessment. The observed agreement between the test and retest postural plane ratings ranged from 59% to 87%; 16 of the 20 plane-condition combinations exceeded 75% observed agreement. Kappa (and prevalence adjusted bias adjusted kappa) values were inconsistent across the postural planes and perturbating conditions. Conclusions: This investigation generally revealed fair to moderate intrarater reliability in the rating of scapular posture by visual inspection. However, enough disagreement between assessments was present to warrant caution when interpreting perceived changes in scapula position between longitudinal assessments using visual inspection alone.

Graph-based concept weighting for medical information retrieval

This paper presents a graph-based method to weight medical concepts in documents for the purposes of information retrieval. Medical concepts are extracted from free-text documents using a state-of-the-art technique that maps n-grams to concepts from the SNOMED CT medical ontology. In our graph-based concept representation, concepts are vertices in a graph built from a document, edges represent associations between concepts. This representation naturally captures dependencies between concepts, an important requirement for interpreting medical text, and a feature lacking in bag-of-words representations. We apply existing graph-based term weighting methods to weight medical concepts. Using concepts rather than terms addresses vocabulary mismatch as well as encapsulates terms belonging to a single medical entity into a single concept. In addition, we further extend previous graph-based approaches by injecting domain knowledge that estimates the importance of a concept within the global medical domain. Retrieval experiments on the TREC Medical Records collection show our method outperforms both term and concept baselines. More generally, this work provides a means of integrating background knowledge contained in medical ontologies into data-driven information retrieval approaches.

Bismuth oxide nanoparticles in the stratosphere

Platey grains of cubic Bi2O3, α-Bi2O3, and Bi2O2.75 nanograins were associated with chondritic porous interplanetary dust particles W7029C1, W7029E5, and 2011C2 that were collected in the stratosphere at 17-19 km altitude. Similar Bi oxide nanograins were present in the upper stratosphere during May 1985. These grains are linked to the plumes of several major volcanic eruptions during the early 1980s that injected material into the stratosphere. The mass of sulfur from these eruptions is a proxy for the mass of stratospheric Bi from which we derive the particle number densities (p m -3) for "average Bi2O3 nanograins" due to this volcanic activity and those necessary to contaminate the extraterrestrial chondritic porous interplanetary dust particles via collisional sticking. The match between both values supports the idea that Bi2O3 nanograins of volcanic origin could contaminate interplanetary dust particles in the Earth's stratosphere. Copyright 1997 by the American Geophysical Union.

Accurate stratospheric particle-size distributions from a flat-plate collection surface

The first representative chemical, structural, and morphological analysis of the solid particles from a single collection surface has been performed. This collection surface sampled the stratosphere between 17 and 19km in altitude in the summer of 1981, and therefore before the 1982 eruptions of El Chichón. A particle collection surface was washed free of all particles with rinses of Freon and hexane, and the resulting wash was directed through a series of vertically stacked Nucleopore filters. The size cutoff for the solid particle collection process in the stratosphere is found to be considerably less than 1 μm. The total stratospheric number density of solid particles larger than 1μm in diameter at the collection time is calculated to be about 2.7×10−1 particles per cubic meter, of which approximately 95% are smaller than 5μm in diameter. Previous classification schemes are expanded to explicitly recognize low atomic number material. With the single exception of the calcium-aluminum-silicate (CAS) spheres all solid particle types show a logarithmic increase in number concentration with decreasing diameter. The aluminum-rich particles are unique in showing bimodal size distributions. In addition, spheres constitute only a minor fraction of the aluminum-rich material. About 2/3 of the particles examined were found to be shards of rhyolitic glass. This abundant volcanic material could not be correlated with any eruption plume known to have vented directly to the stratosphere. The micrometeorite number density calculated from this data set is 5×10−2 micrometeorites per cubic meter of air, an order of magnitude greater than the best previous estimate. At the collection altitude, the maximum collision frequency of solid particles >5μm in average diameter is calculated to be 6.91×10−16 collisions per second, which indicates negligible contamination of extraterrestrial particles in the stratosphere by solid anthropogenic particles.

Layer silicates in a chondritic porous interplanetary dust particle

Analytical electron microscopy on individual grains from a portion of a chondritic porous interplanetary dust particle (aggregate W7029C1 from the NASA Johnson Space Center Cosmic Dust Collection) shows that layer silicates compose 50 percent of the silicate fraction examined. These layer silicates can be classified into two distinct crystallochemical groups: (1) fine-grained, polycrystalline smectite minerals; and (2) well-ordered, single crystals of kaolinite and Mg-poor talc. The layer silicates in this portion of sample W7029(asterisk)A are dissimilar to those described in other chondritic porous aggregates. The predominant layer silicate assemblage in W7029(asterisk)A indicates that heating of the aggregate during atmospheric entry was brief and probably to a temperature less than 300C. Comparison with terrestrial phyllosilicate occurrences suggests that some layer silicates in aggregate W7029(asterisk)A may have been formed by alteratiton from preexisting silicate minerals at low temperatures (less than 25C) after aggregate formation.