14,879 research outputs found
Validating a postural evaluation method developed using a Digital Image-based Postural Assessment (DIPA) software
No full textAbstractObjectiveTo investigate (1) the accuracy of the palpatory method to identify anatomical points by comparison with the X-ray exams, (2) the validity of classifying spinal posture in the frontal plane using Digital Image-Based Postural Assessment (DIPA) software by comparison with the X-ray exams and (3) the intra and inter-evaluator reproducibility of the DIPA software.Materials and methodsThe postural assessment and X-ray examination of the spine, both in the frontal plane and standing position, were performed consecutively in 24 subjects. The postural assessment protocol consisted of: (1) palpation and the use of reflective markers containing lead to mark the spinous processes (SP) of the C7, T2, T4, T6, T8, T10, T12, L2, L4 and S2 vertebrae and; (2) acquisition of photographic records. First, the X-ray examinations were used to check the correlation between the palpated and marked SP and the true location of the SP of the vertebra in question, by assessing the distance between them. The spinal posture was classified based on the calculation of the scoliosis arrows in the DIPA (DIPA-SA). The X-ray examinations provided the scoliosis arrows (X-SA), the Cobb angles and the classification of spinal posture based on the Cobb angle. The results from the DIPA protocol were compared to those from the X-ray examination-based protocol. The statistical tests used were: (1) Kruskal–Wallis – differences in terms of the numerical distance between the markers and the anatomical landmarks, (2) Pearson's Correlation – DIPA-SA and Cobb angles, (3) Pearson's Correlation – X-SA and DIPA-SA; (4) Bland and Altman's graphic representation – X-SA and DIPA-SA, (5) Spearman's Correlation – classification of spinal posture obtained using the X-ray and DIPA protocols, (6) the intraclass correlation test (ICC) for the relationship between the DIPA-SA made by each evaluator (inter-evaluator), and (7) independent t-test to compare the data from the two evaluation days (intra-evaluator), α=0.05.ResultsThere were no significant differences between the location of the anatomical points located using palpation and identified with reflective markers and the respective location of the SP as identified using X-ray exams (χ2=9.366, p=0.404). Significant correlations were found between the DIPA-SA and the Cobb angles in the dorsal (r=0.75, p<0.001) and lumbar (r=0.76, p=0.007) regions; between the DIPA-SA and the X-SA in the dorsal (r=0.79, p<0.001) and lumbar (r=0.92, p<0.001) regions and; between the classifications of posture obtained with the DIPA and X-ray protocols (r=0.804, p<0.001). Bland and Altman's representation showed agreement between DIPA-SA and X-SA for both curvatures. Significant correlations were found for the intra-evaluator test in the thoracic (r=0.99, p<0.001) and lumbar (r=0.98, p<0.001) regions; for the inter-evaluator test in the thoracic (r=0.99, p<0.001) and lumbar (r=0.88, p<0.001) regions.ConclusionThe results suggest that the DIPA protocol constitutes a valid simple, practical and low-cost non-invasive tool for the evaluation of the spine in the frontal plane which can be used to obtain reproducible measurements (inter and intra-evaluators)
[Letter from Alex Bradford to Lieutenant and Mrs. Ray Starner - November 4, 1940]
No full textLetter from Alex Bradford to Lieutenant and Mrs. Ray Starner describing the the current state of affairs that the author was experiencing, including: the London blitz, the moral of the troops on the ground, and the collective company of men opposing the Nazi regime
Remediation of DIPA Contaminated Wastewater Using Visible Light Active Bimetallic Cu-Fe/TiO2 Photocatalyst
No full textAbstractAlkanolamine is widely applied in industry usually for gas treatment process to remove acid gases prior to utilization. Though the absorbent is recycled through the system, some carry over into water stream is unavoidable. Due to high solubility and toxicity of the absorbent, simple removal process or conventional wastewater treatments are inefficient to treat the contaminated water. The photocatalytic degradation of organic compounds were reported to be efficient for treatment or persistent pollutant. In this paper, the synthesized TiO2 was modified with Cu, Fe or Cu-Fe via wet impregnation method. Characterization of the prepared photocatalysts were conducted using BET analyzer, X-ray diffractometer, transmission electron microscope, diffuse reflectance UV–Vis spectrophotometer, and point of zero charge determination. The band gap of the photocatalysts was reduced to as low as 2.55eV (1.8Cu-0.2Fe/TiO2) compared to bare TiO2 with a band gap of 3.11eV. The performance of the photocatalysts for photodegradation of diisopropanolamine (DIPA) was studied using a batch glass reactor under simulated sunlight. The bimetallic photocatalyst 1.8Cu-0.2Fe/TiO2 displayed the highest chemical oxygen demand (COD) and DIPA removals of 67% and 92%, respectively. Based on the photocatalytic degradation data, all the photocatalysts were found to follow pseudo−first order kinetic with 1.8Cu-0.2Fe/TiO2 giving the highest apparent rate constant, kapp = 16.5×10-3 min-1
The student's guide to completing an author study
No full textThe 'Student's guide to completing an author study' emerged during the early development of the school library resource center program at Glen Stewart Elementary School in Stratford Canada on Prince Edward Island. This research process centered on an author study, with direct teaching and clear assignment. The resulting model has been adapted to various grade levels and subject areas in different schools.Source type: Electronic(1)http://proquest.umi.com/pqdweb?did=49237063&Fmt=7&clientId=65345&RQT=309&VName=PQ
Active X-ray optics for the next generation of X-ray space telescopes
No full textDescribed within is the design, manufacture, metrology and X-ray testing of an active X-ray
prototype intended for the next generation of X-ray telescopes. One of the challenges faced by
the X-ray telescope community is how to combine high resolution and high sensitivity into one
system, as weight limitations place constraints on the optics that can be launched. Therefore the
mandate of the active X-ray prototype is to provide high sensitivity through the ability of the optics
to be nested and to deliver high angular resolution through the active control of the optic’s form.
Piezoelectric unimorph actuators provide the active component: it is intended that they will correct
for figure errors within the optic and therefore increase the angular resolution capability.
The prototype’s design is based upon an ellipsoidal segment which provides point-to-point
focussing of an X-ray source. The prototype itself is composed of an electroformed nickel optic
where the non-reflective surface is populated with 30 piezoelectric actuators and it is the production
of the prototype that is the core of the presented research. Metrology of the actuators’ influence
functions is presented and highlight the prototype’s ability to deform its optic surface by microns.
In addition, the measured influence functions are compared against finite element models and a
distinct similarity between the functions is observed.
The prototype was tested at an X-ray beamline facility in November 2008 and the results
showed the prototype’s ability to correct the optic to achieve an improved angular resolution: from
0.786 arc-minutes to 0.686 arc-minutes in terms of full width half maximum. Finally, difficulties
in the manufacture of the prototype and X-ray testing shall be presented alongside future work in
conclusion to this thesis
Author, Geraldine Brooks at the National Library of Australia for the 2009 Ray Mathew Lecture, Canberra, 23 October 2009 [picture] /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author, Geraldine Brooks during her visit to the National Library of Australia for the 2009 Ray Mathew Lecture, Canberra, 23 October 2009.; Acquired in digital format; access copy available online.; Mode of access: Internet via World Wide Web.; Photographed by a staff member of the National Library of Australia
TRANSITION-METAL COMPLEXES OF THE NOVEL TRIDENTATE DI-2-PYRIDYLMETHANAMINE (DIPA)
No full textThe first row transition metal complexes [M(dipa)2]n+ (dipa = di-2-pyridylmethanamine, M = Fe(III), Fe(II), Co(III), Ni(II) and Cu(II)) have been synthesized in generally high yields. Stability constants for the labile Co(II), Ni(II), and Cu(II) complexes have been determined by potentiometric titrations and are as follows (log K1, log K2): 7.63 (1), 6.57 (1); 8.55 (1), 8.25 (1); and 8.89 (1), 7.94 (1). A rather large degree of steric strain within the complexes is evident from the X-ray crystal structures of rac-[Fe(dipa)2](ClO4)2.2H2O (monoclinic, P2(1)/n, a = 9.392 (3) angstrom, b = 16.749 (3) angstrom, c = 17.131 (14) angstrom, beta = 96.62 (5)-degrees, Z = 4) rac-[Co(dipa)2](ClO4)3 (orthorhombic, Pcca, a = 17.574 (5) angstrom, b = 8.568 (2) angstrom, c = 19.159 (3) angstrom, Z = 4), meso-[Ni(dipa)2](S2O6).4H2O (triclinic, P1BAR, a = 7.903 (3) angstrom, b = 9.810 (3) angstrom c = 10.900 (2) angstrom, alpha = 113.10 (3)-degrees, beta = 106.01 (3)-degrees, gamma = 96.93 (4)-degrees, Z = 1), and meso- [Cu(dipa)2] (ClO4)2 (monoclinic, P2(1)/n, a = 7.964 (3) angstrom, b = 10.1 54 (2) angstrom, c = 16.842 (4) angstrom, beta = 100.12 (4)-degrees, Z = 2). Molecular mechanics calculations indicate that the formation of rac-[Co(dipa)2]3+ in preference to the meso isomer is dominant, and this is in agreement with experimental results based on NMR spectra of equilibrated solutions. In the case of Cu(II), formation of the meso isomer is not selective, and this was confirmed by the successful Cu(II)-directed template condensation of the rac isomer with formaldehyde and nitroethane. Calculations also indicate that the rac isomer of the Ni(II) complex is more stable than the crystallized meso isomer
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
X-ray polarization in relativistic jets
No full textWe investigate the polarization properties of Comptonized X-rays from relativistic jets in active galactic nuclei (AGN) using Monte Carlo simulations. We consider three scenarios commonly proposed for the observed X-ray emission in AGN: Compton scattering of blackbody photons emitted from an accretion disc; scattering of cosmic microwave background (CMB) photons and self-Comptonization of intrinsically polarized synchrotron photons emitted by jet electrons. Our simulations show that for Comptonization of disc and CMB photons, the degree of polarization of the scattered photons increases with the viewing inclination angle with respect to the jet axis. In both cases, the maximum linear polarization is ≈20 per cent. In the case of synchrotron self-Comptonization (SSC), we find that the resulting X-ray polarization depends strongly on the seed synchrotron photon injection site, with typical fractional polarizations P≈ 10–20 per cent when synchrotron emission is localized near the jet base, while P≈ 20–70 per cent for the case of uniform emission throughout the jet. These results indicate that X-ray polarimetry may be capable of providing unique clues to identify the location of particle acceleration sites in relativistic jets. In particular, if synchrotron photons are emitted quasi-uniformly throughout a jet, then the observed degree of X-ray polarization may be sufficiently different for each of the competing X-ray emission mechanisms (synchrotron, SSC or external Comptonization) to determine which is the dominant process. However, X-ray polarimetry alone is unlikely to be able to distinguish between disc and CMB Comptonization
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Observations of the 57Fe+23 hyperfine transition in clusters of galaxies
No full textWe present a search for the hyperfine transition of the 57Fe+23 ion at 3.071 mm in clusters of galaxies with the ATNF Mopra telescope. The results are compared with a realistic estimate of the peak brightness temperature of the line in a cooling flow cluster A85, using the available X-ray data
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