804 research outputs found

    Robust point correspondence applied to two and three-dimensional image registration

    Get PDF
    Accurate and robust correspondence calculations are very important in many medical and biological applications. Often, the correspondence calculation forms part of a rigid registration algorithm, but accurate correspondences are especially important for elastic registration algorithms and for quantifying changes over time. In this paper, a new correspondence calculation algorithm, CSM (correspondence by sensitivity to movement), is described. A robust corresponding point is calculated by determining the sensitivity of a correspondence to movement of the point being matched. If the correspondence is reliable, a perturbation in the position of this point should not result in a large movement of the correspondence. A measure of reliability is also calculated. This correspondence calculation method is independent of the registration transformation and has been incorporated into both a 2D elastic registration algorithm for warping serial sections and a 3D rigid registration algorithm for registering pre and postoperative facial range scans. These applications use different methods for calculating the registration transformation and accurate rigid and elastic alignment of images has been achieved with the CSM method. It is expected that this method will be applicable to many different applications and that good results would be achieved if it were to be inserted into other methods for calculating a registration transformation from correspondence

    Clarification of the relationship between bound and scattering states in quantum mechanics: Application to 12C + alpha

    Full text link
    Using phase-equivalent supersymmetric partner potentials, a general result from the inverse problem in quantum scattering theory is illustrated, i.e., that bound-state properties cannot be extracted from the phase shifts of a single partial wave, as a matter of principle. In particular, recent R-matrix analyses of the 12C + alpha system, extracting the asymptotic normalization constant of the 2+ subthreshold state, C12, from the l=2 elastic-scattering phase shifts and bound-state energy, are shown to be unreliable. In contrast, this important constant in nuclear astrophysics can be deduced from the simultaneous analysis of the l=0, 2, 4, 6 partial waves in a simplified potential model. A new supersymmetric inversion potential and existing models give C12=144500+-8500 fm-1/2.Comment: Expanded version (50% larger); three errors corrected (conversion of published reduced widths to ANCs); nine references added, one remove

    Quantitative evaluation of polymer gel dosimeters by broadband ultrasound attenuation

    Get PDF
    Ultrasound has been examined previously as an alternative readout method for irradiated polymer gel dosimeters, with authors reporting varying dose response to ultrasound transmission measurements. In this current work we extend previous work to measure the broadband ultrasound attenuation (BUA) response of irradiated PAGAT gel dosimeters, using a novel ultrasound computed tomography system

    Deriving the ultrastructure of α-crustacyanin using lower-resolution structural and biophysical methods

    Get PDF
    The structure of α-crustacyanin has been determined to 30 Å resolution using negative-stain electron microscopy (EM) single-particle averaging and modelling with the β-crustacyanin dimer from the crystal structure (Protein Data Bank code 1gka), guided by PISA protein subunit interface calculations for 1gka, and compared with the protein arrangements observed in the crystal lattice of 1gka. This α-crustacyanin EM model has been checked against SAXS experimental data, including comparison with rigid-body models calculated from the SAXS data, and finally with analytical ultracentrifugation measurements

    Modelling tsunami inundation on coastlines with characteristic form

    Get PDF
    This paper provides an indication of the likely difference in tsunami amplification and dissipation between different characteristic coastal embayments, coastal entrances and estuaries. Numerical modeling is performed with the ANU/Geoscience Australia tsunami inundation model. Characteristic coastal morphology is represented by simpler generic morphological shapes which can be applied easily in the ANUGA model, such that key non-dimensional parameters (e.g. embayment depth/bay width) can be varied. Modeling is performed with a range of bay shapes, seabed gradient and different incident tsunami wave shapes and wave angles, including sine waves, solitary waves and leading depression Nwaves. The results show a complex pattern for both large and small embayments, with wave breaking an important control on the amplification of the wave between the 20m contour and the shore. For large embayments, the wave run-up can be amplified by a factor six in comparison to the amplitude at the model boundary. For small embayments, the amplification is dependent on the location of the ocean water line, or tidal stage

    Lack of regional pathways impact on surgical delay: Analysis of the Orthopaedic Trauma Hospital Outcomes-Patient Operative Delays (ORTHOPOD) study.

    Get PDF
    INTRODUCTION: Current practice following injury within the United Kingdom is to receive surgery, at the institution of first contact regardless of ability to provide timely intervention and inconsiderate of neighbouring hospital resource and capacity. This can lead to a mismatch of demand and capacity, delayed surgery and stress within hospital systems, particularly with regards to elective services. We demonstrate through a multicentre, multinational study, the impact of this at scale. METHODOLOGY: ORTHOPOD data collection period was between 22/08/2022 and 16/10/2022 and consisted of two arms. Arm 1 captured orthopaedic trauma caseload and capacity in terms of sessions available per centre and patients awaiting surgery per centre per given week. Arm 2 recorded patient and injury demographics, time of decision making, outpatient and inpatient timeframes as well as time to surgery. Hand and spine cases were excluded. For this regional comparison, regional trauma networks with a minimum of four centres enroled onto the ORTHOPOD study were exclusively analysed. RESULTS: Following analysis of 11,202 patient episodes across 30 hospitals we found no movement of any patient between hospitals to enable prompt surgery. There is no current system to move patients, between regional centres despite clear discrepancies in workload per capacity across the United Kingdom. Many patients wait for days for surgery when simple transfer to a neighbouring hospital (within 10 miles in many instances) would result in prompt care within national guidelines. CONCLUSION: Most trauma patients in the United Kingdom are managed exclusively at the place of first presentation, with no consideration of alternative pathways to local hospitals that may, at that time, offer increased operative capacity and a shorter waiting time. There is no oversight of trauma workload per capacity at neighbouring hospitals within a regional trauma network. This leads to a marked disparity in waiting time to surgery, and subsequently it can be inferred but not proven, poorer patient experience and outcomes. This inevitably leads to a strain on the overall trauma system and across several centres can impact on elective surgery recovery. We propose the consideration of inter-regional network collaboration, aligned with the Major Trauma System

    EMAGE: a spatial database of gene expression patterns during mouse embryo development

    Get PDF
    EMAGE () is a freely available, curated database of gene expression patterns generated by in situ techniques in the developing mouse embryo. It is unique in that it contains standardized spatial representations of the sites of gene expression for each gene, denoted against a set of virtual reference embryo models. As such, the data can be interrogated in a novel and abstract manner by using space to define a query. Accompanying the spatial representations of gene expression patterns are text descriptions of the sites of expression, which also allows searching of the data by more conventional text-based methods

    EMAGE: a spatial database of gene expression patterns during mouse embryo development

    Get PDF
    EMAGE () is a freely available, curated database of gene expression patterns generated by in situ techniques in the developing mouse embryo. It is unique in that it contains standardized spatial representations of the sites of gene expression for each gene, denoted against a set of virtual reference embryo models. As such, the data can be interrogated in a novel and abstract manner by using space to define a query. Accompanying the spatial representations of gene expression patterns are text descriptions of the sites of expression, which also allows searching of the data by more conventional text-based methods

    EMAGE—Edinburgh Mouse Atlas of Gene Expression: 2008 update

    Get PDF
    EMAGE (http://genex.hgu.mrc.ac.uk/Emage/database) is a database of in situ gene expression patterns in the developing mouse embryo. Domains of expression from raw data images are spatially integrated into a set of standard 3D virtual mouse embryos at different stages of development, allowing data interrogation by spatial methods. Sites of expression are also described using an anatomy ontology and data can be queried using text-based methods. Here we describe recent enhancements to EMAGE which include advances in spatial search methods including: a refined local spatial similarity search algorithm, a method to allow global spatial comparison of patterns in EMAGE and subsequent hierarchical-clustering, and spatial searches across multiple stages of development. In addition, we have extended data access by the introduction of web services and new HTML-based search interfaces, which allow access to data that has not yet been spatially annotated. We have also started incorporating full 3D images of gene expression that have been generated using optical projection tomography (OPT)

    Peculiar properties of the cluster-cluster interaction induced by the Pauli exclusion principle

    Full text link
    Role of the Pauli principle in the formation of both the discrete spectrum and multi-channel states of the binary nuclear systems composed of clusters is studied in the Algebraic Version of the resonating-group method. Solutions of the Hill-Wheeler equations in the discrete representation of a complete basis of the Pauli-allowed states are discussed for 4He+n, 3H+3H, and 4He+4He binary systems. An exact treatment of the antisymmetrization effects are shown to result in either an effective repulsion of the clusters, or their effective attraction. It also yields a change in the intensity of the centrifugal potential. Both factors significantly affect the scattering phase behavior. Special attention is paid to the multi-channel cluster structure 6He+6He as well as to the difficulties arising in the case when the two clustering configurations, 6He+6He and 4He+8He, are taken into account simultaneously. In the latter case the Pauli principle, even in the absence of a potential energy of the cluster-cluster interaction, leads to the inelastic processes and secures an existence of both the bound state and resonance in the 12Be compound nucleus.Comment: 17 pages, 14 figures, 1 table; submitted to Phys.Rev.C Keywords: light neutron-rich nuclei, cluster model
    • …
    corecore