The effect of dynamic topography and gravity on lithospheric effective elastic thickness estimation: A case study

Lithospheric effective elastic thickness (T e ), a proxy for plIate strength, is helpful for the understanding of subduction characteristics. Affected by curvature, faulting and magma activity, lithospheric strength near trenches should be weakened but some regional inversion studies have shown much higher T e values along some trenches than in their surroundings. In order to improve T e -estimation accuracy, here we discuss the long-wavelength effect of dynamic topography and gravity on T e estimation by taking the Izu-Bonin-Mariana (IBM) Trench as a case study area. We estimate the long-wavelength influence of the density and negative buoyancy of the subducting slab on observed gravity anomalies and seafloor topography. The residual topography and gravity are used to map T e using the fan-wavelet coherence method. Maps of T e , both with and without the effects of dynamic topography and slab gravity anomaly, contain a band of high-T e values along the IBM Trench, though these values and their errors are lower when slab effects are accounted for. Nevertheless, tests show that the T e map is relatively insensitive to the choice of slab-density modelling method, even though the dynamic topography and slab-induced gravity anomaly vary considerably when the slab density is modelled by different methods. The continued presence of a high-T e band along the trench after application of dynamic corrections shows that, before using 2-D inversion methods to estimate T e variations in subduction zones, there are other factors that should be considered besides the slab dynamic effects on the overriding plate

How Sample Completeness Affects Gamma-Ray Burst Classification

Unsupervised pattern recognition algorithms support the existence of three gamma-ray burst classes; Class I (long, large fluence bursts of intermediate spectral hardness), Class II (short, small fluence, hard bursts), and Class III (soft bursts of intermediate durations and fluences). The algorithms surprisingly assign larger membership to Class III than to either of the other two classes. A known systematic bias has been previously used to explain the existence of Class III in terms of Class I; this bias allows the fluences and durations of some bursts to be underestimated (Hakkila et al., ApJ 538, 165, 2000). We show that this bias primarily affects only the longest bursts and cannot explain the bulk of the Class III properties. We resolve the question of Class III existence by demonstrating how samples obtained using standard trigger mechanisms fail to preserve the duration characteristics of small peak flux bursts. Sample incompleteness is thus primarily responsible for the existence of Class III. In order to avoid this incompleteness, we show how a new dual timescale peak flux can be defined in terms of peak flux and fluence. The dual timescale peak flux preserves the duration distribution of faint bursts and correlates better with spectral hardness (and presumably redshift) than either peak flux or fluence. The techniques presented here are generic and have applicability to the studies of other transient events. The results also indicate that pattern recognition algorithms are sensitive to sample completeness; this can influence the study of large astronomical databases such as those found in a Virtual Observatory.Comment: 29 pages, 6 figures, 3 tables, Accepted for publication in The Astrophysical Journa

How do doctors use information in real-time? A qualitative study of internal medicine resident precepting

Background  Despite the importance of evidence-based medicine in medical education, little observational research exists on how doctors-in-training seek and use evidence from information resources in ambulatory care. Objective  To describe information exchange behaviour by internal medicine residents and attendings in ambulatory resident clinic precepting rooms. Design  We observed resident behaviour and audiotaped resident–attending doctor interactions during precepting sessions. Participants  Participating residents included 70 of an eligible 89 residents and 28 of 34 eligible attendings from one large academic internal medicine residency programme in the Midwestern USA. Residents were observed during 95 separate precepting interactions at four ambulatory sites. Approach  Using a qualitative approach, we analysed transcripts and field notes of observed behaviours and interactions looking for themes of information exchange. Coders discussed themes which were refined using feedback from an interdisciplinary panel. Results  Four themes of information exchange behaviour emerged: (i) questioning behaviours that were used as part of the communication process in which the resident and attending doctor could reason together; (ii) searching behaviour of non-human knowledge sources occurred in a minority of precepting interations; (iii) unsolicited knowledge offering and (iv) answering behaviours were important means of exchanging information. Conclusions  Most clinic interactions between resident and attending doctors relied heavily on spoken deliberation without resorting to the scientific literature or other published information resources. These observations suggest a range of factors that may moderate information exchange behaviour in the precepting context including relationships, space and efficiency. Future research should aim to more readily adapt information resources to the relationships and practice context of precepting.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72879/1/j.1365-2753.2006.00752.x.pd

Prospects for photon blockade in four level systems in the N configuration with more than one atom

We show that for appropriate choices of parameters it is possible to achieve photon blockade in idealised one, two and three atom systems. We also include realistic parameter ranges for rubidium as the atomic species. Our results circumvent the doubts cast by recent discussion in the literature (Grangier et al Phys. Rev Lett. 81, 2833 (1998), Imamoglu et al Phys. Rev. Lett. 81, 2836 (1998)) on the possibility of photon blockade in multi-atom systems.Comment: 8 page, revtex, 7 figures, gif. Submitted to Journal of Optics B: Quantum and Semiclassical Optic

Sonographically Guided Posterior Subtalar Joint Injections via the Sinus Tarsi Approach

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135311/1/jum201534183.pd

Light Gluino Constituents of Hadrons and a Global Analysis of Hadron Scattering Data

Light strongly interacting supersymmetric particles may be treated as partonic constituents of nucleons in high energy scattering processes. We construct parton distribution functions for protons in which a light gluino is included along with standard model quark, antiquark, and gluon constituents. A global analysis is performed of a large set of data from deep-inelastic lepton scattering, massive lepton pair and vector boson production, and hadron jet production at large values of transverse momentum. Constraints are obtained on the allowed range of gluino mass as a function of the value of the strong coupling strength alpha_s(M_Z) determined at the scale of the Z boson mass. We find that gluino masses as small as 10 GeV are admissible provided that alpha_s(M_Z) \ge 0.12. Current hadron scattering data are insensitive to the presence of gluinos heavier than ~ 100 - 150 GeV.Comment: 31 pages, 12 figures, RevTe

Do we practice what we preach? A qualitative assessment of resident–preceptor interactions for adherence to evidence‐based practice

Background  Evidence‐based medicine (EBM) is important in training doctors for high‐quality care. Yet little is known about whether ambulatory precepting incorporates the concepts and principles of EBM. Methods  The authors observed and audiotaped 95 internal medicine residency precepting interactions and rated interactions using a qualitative analytic template consisting of three criteria: (1) presence of clinical questions; (2) presence of an evidence‐based process; and (3) resident ability to articulate a clinical question. Results  Sixty‐seven of 95 audio tapes (71%) were of acceptable quality to allow template analysis. Thirty (45%) contained explicit clinical questions; 11 (16%) included an evidence‐based process. Resident ability to articulate a clinical question when prompted was rated as at least ‘fair’ in 59 of 67 interactions (88%). Conclusions  EBM was not optimally implemented in these clinics. Future research could explore more systematically what factors facilitate or impair the use of EBM in the real‐time ambulatory training context.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99027/1/j.1365-2753.2008.00966.x.pd

Structure of Disk Dominated Galaxies I. Bulge/Disk Parameters, Simulations, and Secular Evolution

(Abridged) A robust analysis of galaxy structural parameters, based on the modeling of bulge and disk brightnesses in the BVRH bandpasses, is presented for 121 face-on and moderately inclined late-type spirals. Each surface brightness (SB) profile is decomposed into a sum of a generalized Sersic bulge and an exponential disk. The reliability and limitations of our bulge-to-disk (B/D) decompositions are tested with extensive simulations of galaxy brightness profiles (1D) and images (2D). Galaxy types are divided into 3 classes according to their SB profile shapes; Freeman Type-I and Type-II, and a third ``Transition'' class for galaxies whose profiles change from Type-II in the optical to Type-I in the infrared. We discuss possible interpretations of Freeman Type-II profiles. The Sersic bulge shape parameter for nearby Type-I late-type spirals shows a range between n=0.1-2 but, on average, the underlying surface density profile for the bulge and disk of these galaxies is adequately described by a double-exponential distribution. We confirm a coupling between the bulge and disk with a scale length ratio r_e/h=0.22+/-0.09, or h_bulge/h_disk=0.13+/-0.06 for late-type spirals, in agreement with recent N-body simulations of disk formation and models of secular evolution. This ratio increases from ~0.20 for late-type spirals to ~0.24 for earlier types. The similar scaling relations for early and late-type spirals suggest comparable formation and/or evolution scenarios for disk galaxies of all Hubble types.Comment: 78 pages with 23 embedded color figures + tables of galaxy structural parameters. Accepted for publication in the Astrophysical Journal. The interested reader is strongly encouraged to ignore some of the low res figures within; instead, download the high resolution version from http://www.astro.ubc.ca/people/courteau/public/macarthur02_disks.ps.g

Measurement of Neutrino-Electron Scattering Cross-Section with a CsI(Tl) Scintillating Crystal Array at the Kuo-Sheng Nuclear Power Reactor

The $\bar{\nu}_{e}-e^{-}$ elastic scattering cross-section was measured with a CsI(Tl) scintillating crystal array having a total mass of 187kg. The detector was exposed to an average reactor $\bar{\nu}_{e}$ flux of $\rm{6.4\times 10^{12} ~ cm^{-2}s^{-1}}$ at the Kuo-Sheng Nuclear Power Station. The experimental design, conceptual merits, detector hardware, data analysis and background understanding of the experiment are presented. Using 29882/7369 kg-days of Reactor ON/OFF data, the Standard Model(SM) electroweak interaction was probed at the squared 4-momentum transfer range of $\rm{Q^2 \sim 3 \times 10^{-6} ~ GeV^2}$. The ratio of experimental to SM cross-sections of $\xi =[ 1.08 \pm 0.21(stat)\pm 0.16(sys)]$ was measured. Constraints on the electroweak parameters $(g_V , g_A)$ were placed, corresponding to a weak mixing angle measurement of \s2tw = 0.251 \pm 0.031({\it stat}) \pm 0.024({\it sys}) . Destructive interference in the SM \nuebar -e process was verified. Bounds on anomalous neutrino electromagnetic properties were placed: neutrino magnetic moment at \mu_{\nuebar}< 2.2 \times 10^{-10} \mu_{\rm B} and the neutrino charge radius at -2.1 \times 10^{-32} ~{\rm cm^{2}} < \nuchrad < 3.3 \times 10^{-32} ~{\rm cm^{2}}, both at 90% confidence level.Comment: 18 Figures, 7 Tables; published version as V2 with minor revision from V