4,418 research outputs found
Digital Preservation and Astronomy: Lessons for funders and the funded
Astronomy looks after its data better than most disciplines, and it is no
coincidence that the consensus standard for the archival preservation of all
types of digital assets -- the OAIS Reference Model -- emerged originally from
the space science community.
It is useful to highlight both what is different about astronomy (and indeed
about Big Science in general), what could be improved, and what is exemplary,
and in the process I will give a brief introduction to the framework of the
OAIS model, and its useful conceptual vocabulary. I will illustrate this with a
discussion of the spectrum of big-science data management practices from
astronomy, through gravitational wave (GW) data, to particle physics.Comment: 4 pages, 1 figure, to appear in proceedings of ADASS XX; corresponds
to LIGO document P100017
Managing Research Data in Big Science
The project which led to this report was funded by JISC in 2010--2011 as part of its 'Managing Research Data' programme, to examine the way in which Big Science data is managed, and produce any recommendations which may be appropriate. Big science data is different: it comes in large volumes, and it is shared and exploited in ways which may differ from other disciplines. This project has explored these differences using as a case-study Gravitational Wave data generated by the LSC, and has produced recommendations intended to be useful variously to JISC, the funding council (STFC) and the LSC community. In Sect. 1 we define what we mean by 'big science', describe the overall data culture there, laying stress on how it necessarily or contingently differs from other disciplines. In Sect. 2 we discuss the benefits of a formal data-preservation strategy, and the cases for open data and for well-preserved data that follow from that. This leads to our recommendations that, in essence, funders should adopt rather light-touch prescriptions regarding data preservation planning: normal data management practice, in the areas under study, corresponds to notably good practice in most other areas, so that the only change we suggest is to make this planning more formal, which makes it more easily auditable, and more amenable to constructive criticism. In Sect. 3 we briefly discuss the LIGO data management plan, and pull together whatever information is available on the estimation of digital preservation costs. The report is informed, throughout, by the OAIS reference model for an open archive
The course and outcome of depression in different cultures: 10-year follow-up of the WHO Collaborative Study on the Assessment of Depressive Disorders
The World Health Organization's study on depressive disorders in different cultures began in 1972. Cohorts of depressed patients were identified in Basle, Montreal, Nagasaki, Teheran and Tokyo. The patients were assessed using standardized measures of social and clinical functioning. Ten-year follow-up data on clinical course, service contact, suicidal acts and social function outcomes were available for 439 (79%) patients. Over one-third (36%) were re-admitted at least once in the follow-up period, half of whom (18%) had very poor clinical outcome. Twenty-four per cent suffered severe social impairment for over half the follow-up period, and over one-fifth (21%) showed no full remissions. The best clinical course (one or two reasonably short episodes of depression with complete remission between episodes) was experienced twice as frequently in patients with a diagnosis of endogenous (65%) as in those diagnosed as suffering from psychogenic depression (29%). Among all patients, a fifth (22%) had at least one episode lasting for more than 1 year, and 10% had an episode lasting over 2 years during follow-up. Death by suicide occurred in 11% of patients, with a further 14% making unsuccessful suicide attempt
Emissions and efficiencies of domestic appliances burning various fuels in South Africa
Assessments of pollution from domestic fuel burning in South Africa have, in the main, based their conclusions on measured ambient pollutant concentrations. This approach does not allow for direct comparison of emissions from different domestic fuel burning appliances. Pollution from domestic fuel burning depends both on appliance efficiency, since a more efficient applianceĀ· will burn less fuel, and appliance emission rates. A test cell was designed and built to measure efficiencies and emissions of various fuel/appliance combinations during cooking and space heating tests representative of field operating conditions. A range of fuels, liquid petroleum gas (LPG), paraffin, coal and wood were burnt in domestic appliances commonly used in South Africa. Emissions of gaseous pollutants, C02 , CO, NOx and HC, and particulate pollutants, total suspended particulates (TSP) and particles less than 2.SĪ¼rn aerodynamic diameter, were measured
Lithologies contributing to the clast population in Apollo 17 LKFM basaltic impact melts
LKFM basaltic impact melts are abundant among Apollo lunar samples, especially those from Apollo 15, 16, and 17. They are generally basaltic in composition, but are found exclusively as impact melts. They seem to be related to basins and so could represent the composition of the lower lunar crust. They contain lithic clasts that cannot be mixed in any proportion to produce the composition of the melt matrix; components rich in transition elements (Ti, Cr, Sc) and REE are not considered. To search for the mysterious cryptic component, we previously investigated the mineral clast population in two Apollo 14 LKFM basaltic impact melts, 15445 and 15455. The cryptic component was not present in the mineral clast assemblage of these breccias either, but some olivine and pyroxene grains appeared to be from lithologies not represented among identified igneous rocks from the lunar highlands. In addition, none of the mineral clasts could be unambiguously assigned to a ferroan anorthosite source. We have now extended this study to Apollo 17, starting with two LKFM impact melt breccias (76295 and 76315) from the Apollo 17 station 6 boulder. The results from the study are presented
64-slice computed tomography angiography in the diagnosis and assessment of coronary artery disease : systematic review and meta-analysis
Objective
To assess whether 64-slice computed tomography (CT) angiography might replace some coronary angiography (CA) for diagnosis and assessment of coronary artery disease (CAD).
Methods
We searched electronic databases, conference proceedings and scanned reference lists of included studies. Eligible studies compared 64-slice CT with a reference standard of CA in adults with suspected/known CAD, reporting sensitivity and specificity or true and false positives and negatives. Data were pooled using the hierarchical summary receiver operating characteristic model.
Results
Forty studies were included; 28 provided sufficient data for inclusion in the meta-analyses, all using a cutoff of ā„ 50% stenosis to define significant CAD. In patient-based detection (n=1286) 64-slice CT pooled sensitivity was 99% (95% credible interval (CrI) 97 to 99%), specificity 89% (95% CrI 83 to 94%), median positive predictive value (PPV) across studies 93% (range 64 to 100%) and negative predictive value (NPV) 100% (range 86 to 100%). In segment-based detection (n=14,199) 64-slice CT pooled sensitivity was 90% (95% CrI 85 to 94%), specificity 97% (95% CrI 95 to 98%), median positive predictive value (PPV) across studies 76% (range 44 to 93%) and negative predictive value (NPV) 99% (range 95 to 100%).
Conclusions
64-slice CT is highly sensitive for patient-based detection of CAD and has high NPV. An ability to rule out significant CAD means that it may have a role in the assessment of chest pain, particularly when the diagnosis remains uncertain despite clinical evaluation and simple non-invasive testing.UK National Institute for Health Research Health Technology Assessment programme (project number 06/15/01).
The Health Services Research Unit is core funded by the Chief Scientist Office of the Scottish Government Health Directorates.Peer reviewedAuthor versio
Microstructural controls on the geomechanics of coarse grained soft rocks; Waitemata Group, Auckland
The geomechanical behaviour of a variety of soft rocks from the Waitemata Group, Auckland, is characterised, and the influence of microstructure in determining the geomechanics examined. Field geotechnical measurements of joint spacing and Schmidt Hammer rebound are related to geomechanical properties to determine controls on joint development and applicability of field index tests for soft materials. Samples studied are dominantly sandstones, with one conglomerate; all of which have a significant component of swelling clay minerals. Low bulk densities, high porosities and large void ratios are characteristic of the samples.
They vary from extremely weak, very low durability rocks to moderately: strong and durable materials. Extremely weak sandstones are highly deformable and undergo plastic deformation when loaded in compression. The stronger samples undergo strain softening and respond elastically to applied stresses prior to brittle failure. High softening factors indicate that compressive and tensile strengths are greatly reduced upon saturation.
All the study rocks have high proportions of sand and silt size material (ā¤ 95 %), and up to 10 % of < 2 Ī¼ m proportions; significant gravel size material only occurs in the conglomerate. Volcanic and detrital rock fragments are the dominant constituents in all samples, with abundant quartz, minor calcic plagioclase, and a variety of accessory minerals. The dominant clay is smectite with lesser amounts of illite, kaolinite, and mixed-layer clays.
Individual sand and silt grains are dominantly subrounded to subangular quartz, regular bricks of feldspar, and rods of rutile, and are often clay coated. Microaggregates and grains are combined into aggregates and assemblages, and in some cases macroassemblages, to form granular arrangements, which produce a network of interconnecting pores. The fabric of the rocks is characterised by discontinuous matrices. Fabric types range from skeletal to turbostratic, and arrangements range from tightly interlocking grains to loose granular structures. Clay micro aggregates are either flocculated or form welded FF honeycomb arrangements.
Strength and durability are not influenced by quantity, size, or type of clasts or minerals present; rather, it is the arrangement of individual components (and associated pore spaces) in the rock fabric which directly determines the geomechanical behaviour. Strong, durable samples have an abundance of clean grain to grain contacts, and few large clay aggregates. Clay microaggregates are arranged in welded FF arrangements, and pore space is restricted to micropores which resist water infiltration. Progressively weaker rocks are characterised by an increase in clay coated grains, clay aggregates, and clay connectors (which form weak links for stress transmission), and interconnecting pores at all levels in the fabric. In the weakest rock macroassemblages of clay coated grains, and open flocculated smectitic aggregates connected by point contacts, produce a network of macropores, allowing easy access of water which flocculates clays into weaker states by reducing bonding and cohesion.
Schmidt rebound values in the field do not provide a useful indication of either compressive or tensile strength of these rocks. The rebound values do, however, correlate well with laboratory determined dynamic elasticity values, suggesting that the instrument should be used in the field to predict rock elasticity and not strength.
Joint spacing within the rock units is related to elasticity with units capable of storing stress through plastic deformation having reasonably wide, uniformly spaced joints. Units which release stress through brittle fracture have closely spaced, and more complex joint systems
- ā¦