Search

Your search keyword '"Hewson S"' showing total 155 results
Start Over Author "Hewson S"
155 results on '"Hewson S"'

3. An approach to F-theory

Author

Hewson, S. F.

Subjects
High Energy Physics - Theory
Abstract

We consider BPS configurations in theories with two timelike directions from the perspective of the supersymmetry algebra. We show that whereas a BPS state in a theory with one timelike variable must have positive energy, in a theory with two times any BPS state must have positive angular momentum in the timelike plane, in that $Z_{0\tilde{0}}>0$, where $0$ and $\tilde{0}$ are the two timelike directions. We consider some generic BPS solutions of theories with two timelike directions, and then specialise to the study of the (10,2) dimensional superalgebra for which the spinor operators generate 2-forms and 6-forms. We argue that the BPS configurations of this algebra relate to F-theory in the same way that the BPS configurations of the eleven dimensional supersymmetry algebra relate to M-theory. We show that the twelve dimensional theory is one of fundamental 3-branes and 7-branes, along with their dual partners. We then formulate the new intersection rules for these objects. Upon reduction of this system we find the algebraic description of the IIB-branes and the M-branes. Given these correspondences we may begin an algebraic study of F-theory., Comment: 20 pages, no figures, latex

Published
1997
Full Text
View/download PDF

4. Potentials and T-duality

Author

Hewson, S. F. and Lambert, N. D.

Subjects
High Energy Physics - Theory
Abstract

We discuss the application of T-duality to massive supersymmetric sigma models. In particular (1,1) supersymmetric models with off-shell central charges reveal an interesting structure. The T-duality transformations of the BPS states of these theories are also discussed and an explicit example of Q-kinks is given., Comment: Condensed version to appear in Phys. Lett. B

Published
1997
Full Text
View/download PDF

5. Generalised supersymmetry and p-brane actions

Author

Hewson, S.

Subjects
High Energy Physics - Theory
Abstract

We investigate the most general N=1 graded extension of the Poincare algebra, and find the corresponding supersymmetry transformations and the associated superspaces. We find that the supersymmetry for which {Q,Q} = P is not special, and in fact must be treated democratically with a whole class of supersymmetries. We show that there are two distinct types of grading, and a new class of general spinors is defined. The associated superspaces are shown to be either of the usual type, or flat with no torsion. p-branes are discussed in these general superspaces and twelve dimensions emerges as maximal. New types of brane are discovered which could explain many features of the standard p-brane theories., Comment: 29 pages, LaTex, no figures. Errors in degrees of freedom counting corrected, leading to altered brane scan

Published
1997
Full Text
View/download PDF

6. The twelve dimensional super (2+2)-brane

Author

Hewson, S. F. and Perry, M. J.

Subjects
High Energy Physics - Theory
Abstract

We discuss supersymmetry in twelve dimensions and present a covariant supersymmetric action for a brane with worldsheet signature (2,2), called a super (2+2)-brane, propagating in the osp(64,12) superspace. This superspace is explicitly constructed, and is trivial in the sense that the spinorial part is a trivial bundle over spacetime, unlike the twisted superspace of usual Poincare supersymmetry. For consistency, it is necessary to take a projection of the superspace. This is the same as the projection required for worldvolume supersymmetry. Upon compactification of this superspace, a torsion is naturally introduced and we produce the membrane and type IIB string actions in 11 and 10 dimensional Minkowski spacetimes. In addition, the compactification of the twelve dimensional supersymmetry algebra produces the correct algebras for these theories, including central charges. These considerations thus give the type IIB string and M-theory a single twelve dimensional origin., Comment: 32 pages LaTex, no figures, minor comments and address(!) added

Published
1996
Full Text
View/download PDF

7. Exact non-abelian duality

Author

Hewson, S. F. and Perry, M. J.

Subjects
High Energy Physics - Theory
Abstract

We investigate non-abelian gaugings of WZNW models. When the gauged group is semisimple we are able to present exact formulae for the dual conformal field theory, for all values of the level $k$. The results are then applied to non-abelian target space duality in string theory, showing that the standard formulae are quantum mechanically well defined in the low energy limit if the gauged group is semisimple., Comment: 17 pages uuencoded Z-compressed latex

Published
1996
Full Text
View/download PDF

8. The non-abelian target space duals of Taub-NUT space

Author

Hewson, S. F.

Subjects
High Energy Physics - Theory
Abstract

We discuss the non-abelian duality procedure for groups which do not act freely. As an example we consider Taub-NUT space, which has the local isometry group $SU(2) \otimes U(1)$. We dualise over the entire symmetry group as well as the subgroups $SO(3)$ and $U(1)$, presenting unusual new solutions to low energy string theory. The solutions obtained highlight the relationship between fixed points of an isometry in one solution and singular points in another. We also find the interesting results that, in this case, the $U(1)$ and $SO(3)$ $T$-duality procedures commute with each other, and that the extreme points of the $O(1,1)$ duality group for the time translations have special significance under the $SO(3)$ T-duality., Comment: 26 pages LaTeX, one figure as a uuencoded postscript file

Published
1995
Full Text
View/download PDF

9. Dualities, branes and supersymmetry

Author

Hewson, S. F.

Subjects
530.15
Abstract

Non-abelian target space duality and its effect on low energy string backgrounds is investigated, with particular emphasis on Taub-NUT space. The dual solutions are analysed and the physical effects of the duality are discussed, along with the interrelationship between successive applications of target space duality. A full quantum mechanical analysis of non-abelian duality is then considered. Conditions for the transformation to be anomaly free are presented, along with the quantum corrections to the standard non-abelian duality formulae. A low energy analysis is also performed. The study of D-branes creates an interest in massive sigma models. The supersymmetric abelian target space duals of such models are constructed. From the dual models the correct form of the dual potentials may be inferred. Finally the effects of the duality on the solitons of the massive model are discussed. The general problem of branes in twelve dimensions is studied. A supersymmetric action principle is formulated, but in order to do this the notions of supersymmetric must generalised. The resulting (2 + 2)- brane lives in a new type of superspace with two timelike directions. It is then shown that the traditional spacetime strings and membranes may be obtained by dimensional reduction. Once one has adapted to the possibility that there are many different supersymmetry theories, it is natural to attempt a classification. Details of such a procedure are given, and the corresponding superspaces constructed. In addition, complete brane scans are given for branes in any spacetime dimension and signature, and the algebras for which they are possible. The (2+2)-brane requires there to be two time directions. The concrete properties which any supersymmetric theory with two times must have are thus discussed. The BPS states of the two-time algebras are investigated in an analysis similar to that used in supergravity. Consistency conditions are discussed and the intersection properties of the branes detailed.

Published
1998

10. The Cost Implications in Ontario, Alberta, and British Columbia of Early Versus Delayed External Cephalic Version in the Early External Cephalic Version 2 (EECV2) Trial

Author

Hutton, E.K., Barrett, J., Carson, G.D., Delisle, M.F., Dunn, M., Edwards, S., Fernandez, A., Gafni, A., Hannah, M.E., Hewson, S., Natale, R., Ohlsson, A., Ross, S.J., Willan, A.R., Windrim, R., Pollard, J.K., Schweitzer, Sylvestre, G., Turtle, P., Bracken, M., Crowley, P., Donner, A., Duley, L., Ehrenkranz, R., Curioni, M., Abalos Gorostiaga, R., Becker, C., Elizabeth, P.A., Errandonea, L., Palermo, M., Ramos, C.A., Trabucco, M., Montes Varela, D., Bertin, M.S., Castaldi, J.L., Mohedano de Duhalde, M., Messina, A., Baumgartner, J., Kovacs, G., Malcolm, B., Neil, J.R., Mahomed, K., Green, A., Child, A., DeVries, B., Phipps, H., Welsh, A., Davis, G.K., Roberts, L., Watts, N.P., Cybulski, M., Gibson, D., Tucker, S., McCahon, I., Sheehan, P., Umstad, M., Milligan, J., Morris, J., Rickard, K., Gardener, G., Jenkins-Manning, S., Boniface, C., Edmondson, M., Watson, D., Ayub, A., Soanes, S., Jordan, A., Fanning, C., Parish, B., Watson, M.A., Reid, D., Scheufler, P., Malott, A.M., Reitsma, A., Haslauer, K.A., Lipp, M., Farquharson, D., Gray, K., Demianczuk, N., Penttinen, E., Herer, E., McLean, K., Aghajafari, F., Williams, S., Moravac, C., Yudin, M., Pollard, J., Miller, L., Anderson, R.B., Good, M., Walker, M.C., Kulkarni, R., Scarfone, R., Cameron, C., Peel, T., Carrillo, J., Cruces, A., Gonzalez, Y., Figueroa Poblete, J., Lama Hormazabal, L., Saez, J., Oyarzun, E., Rioseco, A., Illanes, S., Kottmann, C., Parra, M., Quezada, S., Quiroz, L., Hvidman, L., Mogensen, I.M., Mouritzen, A., Ostberg, B., Abdel-Samad, S.N.M., Al-Hussaini, T., El-Nashar, I., Kirss, F., Rull, K., Ustav, E., Vaas, P., Brink-Spalink, V., Weizsaecker, K., Major, T., Poka, R., Daly, S., Kaneti, H., Rosen, D., Schachter, B., Chayen, B., Harel, L., Hiaeb, Z., Malinger, G., Dukler, D., Lunenfeld, E., AlFaris, L., El-Zibdeh, M., Domzalska-Popadiuk, I., Kobiela, P., Pankrac, Z., Preis, J., Preis, K., Swiatkowska-Freund, M., Cravo, J., Theron, A.M., Theron, G.B., Cronje, H.S., du Plessis, J.M., Munoz, M., Khan, G., Khan, S., Goossens, S., Pieters, M., Roumen, F.J.M.E., ten Cate, F., Smits, F., Heres, M., Krabbendam, E., Airey, R., Farrar, D., Tuffnell, D.J., Heyes, V., Melvin, C., Schram, C., Galimberti, A., Stewart, P., Cresswell, J., McCormick, C., Andrews, J., Fleener, D., Coonrod, D., Jimenez, B.F., Brown, S., Gregg, A., Pitchford, C., Seubert, D., Ahmed, Rashid J., Gafni, Amiram, and Hutton, Eileen K.

Published
2016
Full Text
View/download PDF

13. Threebranes in Twelve Dimensions

Author

Hewson, S. F., Baulieu, Laurent, editor, Di Francesco, Philippe, editor, Douglas, Michael, editor, Kazakov, Vladimir, editor, Picco, Marco, editor, and Windey, Paul, editor

Published
1999
Full Text
View/download PDF

14. The Control of Hypertension In Pregnancy Study pilot trial

Author

Magee, L A, von Dadelszen, P, Chan, S, Gafni, A, Gruslin, A, Helewa, M, Hewson, S, Kavuma, E, Lee, S K, Logan, A G, McKay, D, Moutquin, J-M, Ohlsson, A, Rey, E, Ross, S, Singer, J, Willan, A R, and Hannah, M E

Published
2007

24. The natural history of nemaline myopathy

Author

Amburgey, K., primary, Hewson, S., additional, Hum, C., additional, Glueck, M., additional, Sultanum, N., additional, Girdea, M., additional, Brudno, M., additional, Bönnemann, C., additional, Dastgir, J., additional, Amin, R., additional, Mayer, O., additional, Constantinescu, A., additional, Syed, F., additional, Tran, T., additional, Jain, M., additional, Nelson, L., additional, Beggs, A., additional, Genetti, C., additional, Lawlor, M., additional, and Dowling, J., additional

Published
2017
Full Text
View/download PDF

28. P.280 - The natural history of nemaline myopathy

Author

Amburgey, K., Hewson, S., Hum, C., Glueck, M., Sultanum, N., Girdea, M., Brudno, M., Bönnemann, C., Dastgir, J., Amin, R., Mayer, O., Constantinescu, A., Syed, F., Tran, T., Jain, M., Nelson, L., Beggs, A., Genetti, C., Lawlor, M., and Dowling, J.

Published
2017
Full Text
View/download PDF

30. Canadian Spine Society abstracts1.1.01 Supraspinal modulation of gait abnormalities associated with noncompressive radiculopathy may be mediated by altered neurotransmitter sensitivity1.1.02 Neuroprotective effects of the sodium-glutamate blocker riluzole in the setting of experimental chronic spondylotic myelopathy1.1.03 The effect of timing to decompression in cauda equina syndrome using a rat model1.2.04 Intraoperative waste in spine surgery: incidence, cost and effectiveness of an educational program1.2.05 Looking beyond the clinical box: the health services impact of surgical adverse events1.2.06 Brace versus no brace for the treatment of thoracolumbar burst fractures without neurologic injury: a multicentre prospective randomized controlled trial1.2.07 Adverse event rates in surgically treated spine injuries without neurologic deficit1.2.08 Functional and quality of life outcomes in geriatric patients with type II odontoid fracture: 1-year results from the AOSpine North America Multi-Center Prospective GOF Study1.3.09 National US practices in pediatric spinal fusion: in-hospital complications, length of stay, mortality, costs and BMP utilization1.3.10 Current trends in the surgical treatment of adolescent idiopathic scoliosis in Canada1.3.11 Sagittal spinopelvic parameters help predict the risk of proximal junctional kyphosis for children treated with posterior distraction-based implants1.4.12 Correlations between changes in surface topography and changes in radiograph measurements from before to 6 months after surgery in adolescents with idiopathic scoliosis1.4.13 High upper instrumented vertebra (UIV) sagittal angle is associated with UIV fracture in adult deformity corrections1.4.14 Correction of adult idiopathic scoliosis using intraoperative skeletal traction1.5.01 Cauda equina: using management protocols to reduce delays in diagnosis1.5.02 Predicting the need for tracheostomy in patients with acute traumatic spinal cord injury1.5.03 A novel animal model of cervical spondylotic myelopathy: an opportunity to identify new therapeutic targets1.5.04 A review of preference-based measures of health-related quality of life in spinal cord injury research1.5.05 Predicting postoperative neuropathic pain following surgery involving nerve root manipulation based on intraoperative electromyographic activity1.5.06 Detecting positional injuries in prone spinal surgery1.5.07 Percutaneous thoracolumbar stabilization for trauma: surgical morbidity, clinical outcomes and revision surgery1.5.08 Systemic inflammatory response syndrome in spinal cord injury patients: Does its presence at admission affect patient outcomes?2.1.15 One hundred years of spine surgery — a review of the evolution of our craft and practice in the spine surgical century [presentation]2.1.16 Prevalence of preoperative MRI findings of adjacent segment disc degeneration in patients undergoing anterior cervical discectomy and fusion2.1.17 Adverse event rates of surgically treated cervical spondylopathic myelopathy2.1.18 Morphometricand dynamic changes in the cervical spine following anterior cervical discectomy and fusion and cervical disc arthroplasty2.1.19 Is surgery for cervical spondylotic myelopathy cost-effective? A cost–utility analysis based on data from the AO Spine North American Prospective Multicentre CSM Study2.2.20 Cost–utility of lumbar decompression with or without fusion for patients with symptomatic degenerative lumbar spondylolisthesis (DLS)2.2.21 Minimally invasive surgery lumbar fusion for low-grade isthmic and degenerative spondylolisthesis: 2- to 5-year follow-up2.2.22 Results and complications of posterior-only reduction and fusion for high-grade spondylolisthesis2.3.23 Fusion versus no fusion in patients with central lumbar spinal stenosis and foraminal stenosis undergoing decompression surgery: comparison of outcomes at baseline and follow-up2.3.24 Two-year results of interspinous spacers (DIAM) as an alternative to arthrodesis for lumbar degenerative disorders2.3.25 Treatment of herniated lumbar disc by sequestrectomy or conventional discectomy2.4.26 No sustained benefit of continuous epidural analgesia for minimally invasive lumbar fusion: a randomized double-blinded placebo controlled study2.4.27 Evidence and current practice in the radiologic assessment of lumbar spine fusion2.4.28 Wiltse versus midline approach for decompression and fusion of the lumbar spine2.5.09 The effect of soft tissue restraints following type II odontoid fractures in the elderly — a biomechanical study2.5.10 Development of an international spinal cord injury (SCI) spinal column injury basic data set2.5.11 Evaluation of instrumentation techniques for a unilateral facet perch and fracture using a validated soft tissue injury model2.5.12 Decreasing neurologic consequences in patients with spinal infection: the testing of a novel diagnostic guideline2.5.13 Prospective analysis of adverse events in surgical treatment of degenerative spondylolisthesis2.5.14 Load transfer characteristics between posterior fusion devices and the lumbar spine under anterior shear loading: an in vitro investigation2.5.15 Preoperative predictive clinical and radiographic factors influencing functional outcome after lumbar discectomy2.5.16 A Thoracolumbar Injury Classification and Severity Score (TLICS) of 4: What should we really do?3.1.29 Adverse events in emergent oncologic spine surgery: a prospective analysis3.1.30 En-bloc resection of primary spinal and paraspinal tumours with critical vascular involvement3.1.31 The treatment impact of minocycline on quantitative MRI in acute spinal cord injury3.1.32 Benefit of minocycline in spinal cord injury — results of a double-blind randomized placebo-controlled study3.2.33 Improvement of magnetic resonance imaging correlation with unilateral motor or sensory deficits using diffusion tensor imaging3.2.34 Comparing care delivery for acute traumatic spinal cord injury in 2 Canadian centres: How do the processes of care differ?3.2.35 Improving access to early surgery: a comparison of 2 centres3.3.36 The effects of early surgical decompression on motor recovery after traumatic spinal cord injury: results of a Canadian multicentre study3.3.37 A clinical prediction model for long-term functional outcome after traumatic spinal cord injury based on acute clinical and imaging factors3.3.38 Effect of motor score on adverse events and quality of life in patients with traumatic spinal cord injury3.4.39 The impact of facet dislocation on neurologic recovery after cervical spinal cord injury: an analysis of data on 325 patients from the Surgical Trial in Acute Spinal Cord Injury Study (STASCIS)3.4.40 Toward a more precise understanding of the epidemiology of traumatic spinal cord injury in Canada3.4.41 Access to care (ACT) for traumatic SCI: a survey of acute Canadian spine centres3.4.42 Use of the Spine Adverse Events Severity (SAVES) instrument for traumatic spinal cord injury3.5.17 Does the type of distraction-based growing system for early onset scoliosis affect postoperative sagittal alignment?3.5.18 Comparison of radiation exposure during thoracolumbar fusion using fluoroscopic guidance versus anatomic placement of pedicle screws3.5.19 Skeletal traction for intraoperative reduction in adolescent idiopathic scoliosis3.5.20 Utility of intraoperative cone-beam computed tomography (O-ARM) and stereotactic navigation in acute spinal trauma surgery3.5.21 Use of a central compression rod to reduce thoracic level spinal osteotomies3.5.22 ICD-10 coding accuracy for spinal cord injured patients3.5.23 Feasibility of patient recruitment in acute SCI trials3.5.24 Treatment of adult degenerative scoliosis with DLIF approaches

Author

Shamji, M., primary, Moon, E. Su, primary, Glennie, R.A., primary, Soroceanu, A., primary, Lin, C., primary, Bailey, C.S., primary, Simmonds, A., primary, Fehlings, M., primary, Dodwell, E., primary, Dold, A., primary, El-Hawary, R., primary, Hashem, M., primary, Jones, S., primary, Karadimas, S., primary, Whitehurst, D., primary, Norton, J., primary, Manson, N.A, primary, Kesani, A., primary, Bednar, Drew, primary, Lundine, K., primary, Hartig, D., primary, Fichadi, A., primary, Kim, S., primary, Harris, S.A., primary, Gill, J., primary, Abraham, E., primary, Choi, S., primary, Goldstein, C., primary, Wang, Z., primary, McCabe, M., primary, Noonan, V.K., primary, Nadeau, M., primary, Ferrara, S., primary, Kelly, A., primary, Melnyk, A., primary, Arora, D., primary, Quateen, A., primary, Dea, N., primary, Ranganathan, A., primary, Zhang, Y., primary, Casha, S., primary, Rajamanickam, K., primary, Santos, A., primary, Wilson, J., primary, Street, J., primary, Lewis, R., primary, Egge, N., primary, Schouten, R., primary, Kim, A., primary, Kwon, B., primary, Huang, E., primary, Hwang, P., additional, Allen, K., additional, Jing, L., additional, Mata, B., additional, Gabr, M., additional, Richardson, W., additional, Setton, L., additional, Karadimas, S., additional, Fehlings, M., additional, Fleming, J., additional, Bailey, C.S., additional, Gurr, K., additional, Bailey, S., additional, Siddiqi, F., additional, Lawendy, A., additional, Sanders, D., additional, Staudt, M., additional, Canacari, E., additional, Brown, E., additional, Robinson, A., additional, McGuire, K., additional, Chrysostoum, C., additional, Rampersaud, Y. Raja, additional, Dvorak, M.F., additional, Thomas, K.C., additional, Boyd, M.C., additional, Gurr, K.R., additional, Bailey, S.I., additional, Nadeau, M., additional, Fisher, C.G, additional, Batke, J., additional, Street, J., additional, Boyd, M., additional, Dvorak, M., additional, Fisher, C., additional, Kwon, B., additional, Paquette, S., additional, Vaccaro, A., additional, Chapman, J., additional, Arnold, P., additional, Shaffrey, C., additional, Kopjar, B., additional, Snyder, B., additional, Wright, J., additional, Lewis, S., additional, Zeller, R., additional, El-Hawary, R., additional, Moroz, P., additional, Bacon, S., additional, Jarzem, P., additional, Hedden, D., additional, Howard, J., additional, Sturm, P., additional, Cahill, P., additional, Samdani, A., additional, Vitale, M., additional, Gabos, P., additional, Bodin, N., additional, d’Amato, C., additional, Harris, C., additional, Smith, J., additional, Parent, E., additional, Hill, D., additional, Moreau, M., additional, Mahood, J., additional, Bodrogi, A., additional, Abbas, H., additional, Goldstein, S., additional, Bronstein, Y., additional, Chua, S., additional, Magana, S., additional, Van Houwelingen, A., additional, Halpern, E., additional, Jhaveri, S., additional, Lim, A., additional, Leelapattana, P., additional, Siddiqqi, F., additional, Moon, E. Su, additional, Satkunendrarajah, K., additional, Noonan, V., additional, Bryan, S., additional, Aronyk, K., additional, Fox, R., additional, Nataraj, A., additional, Pugh, J., additional, Elliott, R., additional, McKeon, M., additional, Abraham, E.P., additional, Davis, G., additional, Rogers, M., additional, Staples, M., additional, Quan, G., additional, Shamji, M., additional, Hurlbert, R.J., additional, Jacobs, W.B., additional, Duplessis, S., additional, Casha, S., additional, Jha, N., additional, Hewson, S., additional, Massicotte, E., additional, Mortaz, S., additional, Coyte, P., additional, Rampersaud, Y.R., additional, Andrew, B., additional, Modi, H., additional, Roffey, D., additional, Miles, I., additional, Wai, E., additional, Manson, N., additional, Eastwood, D., additional, Elliot, R., additional, Bains, I., additional, Yong, E., additional, Sutherland, G., additional, Chan, V.W.S., additional, Persaud, O., additional, Koshkin, A., additional, Brull, R., additional, Hassan, N., additional, Petis, S., additional, Kowalczuk, M., additional, Petrisor, B., additional, Drew, B., additional, Bhandari, M., additional, DiPaola, C., additional, McLachlin, S., additional, Bailey, C., additional, Dunning, C., additional, Fehlings, M.G., additional, Wing, P., additional, Itshayek, E., additional, Biering-Sorensen, F., additional, Bradi, A., additional, Pokrupa, R., additional, Kelly, A., additional, Wen, T., additional, Kingwell, S., additional, Chak, J., additional, Singh, V., additional, Cripton, P., additional, Oxland, T., additional, Wali, Z., additional, Yen, D., additional, Alfllouse, A., additional, Alzahrani, A., additional, Jiang, H., additional, Kortbeek, F., additional, Reddy, R., additional, Rampersaud, R., additional, Hurlbert, J., additional, Yong, W., additional, Zygun, D., additional, McGowan, D., additional, Yong, V.W., additional, Mendis, B., additional, Chakraborty, S., additional, Nguyen, T., additional, Tsai, E., additional, Chen, A., additional, Atkins, D., additional, Noonan, V.K., additional, Tsui, D., additional, Townson, A., additional, Craven, C., additional, Ford, M., additional, Ahn, H., additional, Kiss, A., additional, Harrop, J., additional, Grossman, R., additional, Frankowski, R., additional, Guest, J., additional, Aarabi, B., additional, Cheung, A., additional, Sun, B., additional, Marais, L., additional, Queyranne, M., additional, Fourney, D., additional, Johnson, M., additional, Yee, A., additional, Finkelstein, J., additional, Paquet, J., additional, Parent, S., additional, Christie, S., additional, Lange, J., additional, Lapinsky, A., additional, Connolly, P., additional, Eck, J., additional, Rabin, D., additional, Lee, R., additional, Sofia, M., additional, Shin, J., additional, Tung, K., additional, Ghag, R., additional, Goyal, T., additional, Littlewood, J., additional, Cho, R., additional, Thomas, K., additional, and Swamy, G., additional

Published
2012
Full Text
View/download PDF

31. Slope stability major hazard management plan and operating procedures at Cadia Hill open pit, Cadia Valley operations, Newcrest Mining Limited.

Author

Pothitos F., Fifth large open pit conference Kalgoorlie, Western Australia 03-Nov-0305-Nov-03, Clark D.J., Hewson S., Li T., Pothitos F., Fifth large open pit conference Kalgoorlie, Western Australia 03-Nov-0305-Nov-03, Clark D.J., Hewson S., and Li T.

Abstract

Newcrest Mining's Cadia Valley operations are located 250 km west of Sydney, New South Wales, Australia. They include the Cadia Hill and Cadia Extended open pits, where around 70 000 000-100 000 000 tonnes of material are moved a year to mine a monazite-hosted gold copper porphyry deposit. The pit slope design is primarily based on structural controls related to faults and shears. Pit wall slopes have been mined at inter- ramp angles of up to 60 degrees over heights of 120 m. The operating procedures and management plans that have been developed to mitigate the risks of rock falls are described., Newcrest Mining's Cadia Valley operations are located 250 km west of Sydney, New South Wales, Australia. They include the Cadia Hill and Cadia Extended open pits, where around 70 000 000-100 000 000 tonnes of material are moved a year to mine a monazite-hosted gold copper porphyry deposit. The pit slope design is primarily based on structural controls related to faults and shears. Pit wall slopes have been mined at inter- ramp angles of up to 60 degrees over heights of 120 m. The operating procedures and management plans that have been developed to mitigate the risks of rock falls are described.

Published
2003

32. Design and optimisation of Cadia Hill open pit, Cadia Valley operations, Newcrest Mining Limited.

Author

Li T., Fifth large open pit conference Kalgoorlie, Western Australia 03-Nov-0305-Nov-03, Hewson S., Pothitos F., Li T., Fifth large open pit conference Kalgoorlie, Western Australia 03-Nov-0305-Nov-03, Hewson S., and Pothitos F.

Abstract

Newcrest Mining's Cadia Valley operations are located 250 km west of Sydney, New South Wales, Australia. They consist of the Ridgeway underground mine, together with the Cadia Hill and Cadia Extended open pits. The deposit is a low-grade porphyry gold-copper system, and the 17 000 000 tonnes/a ore mined from the open pits produce 300 000 oz/a Au and 23 000 t/a Cu. The Cadia Hill open pit is currently between 250 m and 400 m deep, and will reach a maximum 720 m depth over the remaining nine years of its life. Geological and geotechnical conditions at the pit are complex, and the integration of geotechnical, hydrogeological, mining and production scheduling programmes needed to achieve an optimum design of the pit slopes is described. This current project focuses on the use of risk and return principles in the pit design., Newcrest Mining's Cadia Valley operations are located 250 km west of Sydney, New South Wales, Australia. They consist of the Ridgeway underground mine, together with the Cadia Hill and Cadia Extended open pits. The deposit is a low-grade porphyry gold-copper system, and the 17 000 000 tonnes/a ore mined from the open pits produce 300 000 oz/a Au and 23 000 t/a Cu. The Cadia Hill open pit is currently between 250 m and 400 m deep, and will reach a maximum 720 m depth over the remaining nine years of its life. Geological and geotechnical conditions at the pit are complex, and the integration of geotechnical, hydrogeological, mining and production scheduling programmes needed to achieve an optimum design of the pit slopes is described. This current project focuses on the use of risk and return principles in the pit design.

Published
2003

36. A sociolinguistic exploration of genetic counseling discourse involving a child with a new genetic diagnosis.

Author

Babul-Hirji R, Hewson S, and Frescura M

Abstract

OBJECTIVES: To examine the process of genetic counseling with the aim of observing how participants negotiate a common understanding in light of the inherent power asymmetry of a genetics health care encounter. METHODS: Data from ten sessions between genetic counselors and parents of children with a genetic diagnosis were taped. Transcripts were examined using a qualitative discourse analysis approach focusing on communication features such as question design, topic initiation and control, and lexical or discourse features which could give insights into rapport building strategies. RESULTS: Counselors tightly controlled the medical history phase in all sessions and verbally dominated the scientific information phase. More symmetric communication occurred when: (i) counselors showed flexibility with their agenda and gave parents the opportunity to share their health experience; (ii) counselors showed signs of involvement through the use of 'rapport building' strategies; (iii) counselors used a syllogistic approach and information was delivered at a slower pace. CONCLUSION: Observations from this study suggest that, when counselors focus on building rapport with parents, the human voice of the parent emerges. Examples of rapport building strategies by the counselors included adapting to the parents' variations in knowledge, recognizing the needs of the parents, verifying their understanding, and choosing a more interactive approach to the delivery of information. PRACTICE IMPLICATIONS: Our findings suggest that for effective communication to occur, parents need to be provided with opportunities to be active participants in the genetic counseling encounter. [ABSTRACT FROM AUTHOR]

Published
2010
Full Text
View/download PDF

37. Women's Views of Their Experiences in the CHIPS (Control of Hypertension in Pregnancy Study) Pilot Trial.

Author

Magee, L. A., von Dadelszen, P., Chan, S., Gafni, A., Gruslin, A., Helewa, M., Hewson, S., Kavuma, E., Lee, S. K., Logan, A. G., McKay, D., Moutquin, J.-M., Ohlsson, A., Rey, E., Ross, S., Singer, J., Willan, A. R., and Hannah, M. E.

Subjects
HYPERTENSION in pregnancy, PREECLAMPSIA, BLOOD circulation disorders, BLOOD pressure, PREGNANCY
Abstract

Background: Satisfaction with maternity care is strongly related to the patient-caregiver relationship and involvement in the decision-making process. We sought to compare women's views about their care in a randomized trial of 'less tight' vs. 'tight' control of non-proteinuric pre-existing or gestational hypertension in pregnancy. Methods: In the CHIPS Pilot Trial, women completed a postpartum questionnaire to assess their likes and dislikes about their blood pressure (BP) management and trial participation. Comparisons were descriptive. Results: Baseline information was similar for the 'less tight' and 'tight' control groups. Of 132 women, 126 (95.5%) from 17 centers completed a postpartum questionnaire, usually within days of delivery. At least 90% of women in both groups were satisfied with their care, and would be willing to participate again or recommend participation to a friend. Women in both the 'less tight' and 'tight' groups were satisfied with BP management (98.4% vs. 95.1%), and the frequency of tests of maternal and fetal well being. Half of women in both groups perceived that their BP was too high and that caregivers thought that their BP was too high. More women in the 'less tight' (vs. the 'tight') control group took less medication than expected (71.7% vs. 38.2%). More women in the 'tight' (vs. the 'less tight') group took more medication than they expected (60.0% vs. 22.2%). At least 60% of all women used home BP monitoring. Conclusion: In the CHIPS Pilot Trial, while women stated that they were satisfied with their BP management and care, a surprising 50% in both groups thought that their BP was too high. The majority of women used home BP monitoring, the role of which must be further defined in hypertensive pregnancies. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

38. Maternal outcomes at 2 years after planned cesarean section versus planned vaginal birth for breech presentation at term: the international randomized Term Breech Trial.

Author

Hannah ME, Whyte H, Hannah WJ, Hewson S, Amankwah K, Cheng M, Gafni A, Guselle P, Helewa M, Hodnett ED, Hutton E, Kung R, McKay D, Ross S, Saigal S, Willan A, and 2-Year Maternal Follow-Up Term Breech Trial Collaborative Group

Abstract

OBJECTIVE: This study was undertaken to compare maternal outcomes at 2 years postpartum after planned cesarean section and planned vaginal birth for the singleton fetus in breech presentation at term. STUDY DESIGN: In selected centers in the Term Breech Trial, mothers completed a structured questionnaire at 2 or more years postpartum to determine their health in the previous 3 to 6 months. RESULTS: A total of 917 of 1159 (79.1%) mothers from 85 centers completed a follow-up questionnaire at 2 years postpartum. There were no differences between groups in breast feeding, relationship with child or partner, pain, subsequent pregnancy, incontinence, depression, urinary, menstrual or sexual problems, fatigue, or distressing memories of the birth experience. Planned cesarean section was associated with a higher risk of constipation (P = .02). CONCLUSION: Maternal outcomes at 2 years postpartum are similar after planned cesarean section and planned vaginal birth for the singleton breech fetus at term. [ABSTRACT FROM AUTHOR]

Published
2004
Full Text
View/download PDF

39. Factors associated with adverse perinatal outcome in the Term Breech Trial.

Author

Su M, McLeod L, Ross S, Willan A, Hannah WJ, Hutton E, Hewson S, Hannah ME, Term Breech Trial Collaborative Group, Su, Min, McLeod, Lynne, Ross, Susan, Willan, Andrew, Hannah, Walter J, Hutton, Eileen, Hewson, Sheila, and Hannah, Mary E

Abstract

Background: In the Term Breech Trial, the risk of adverse perinatal outcome was lower with planned cesarean section versus planned vaginal birth. We undertook secondary analyses to determine factors associated with adverse perinatal outcome.Study Design: By using multiple logistic regression analyses, we determined the effect of prelabor cesarean section, cesarean section during early labor, cesarean section during active labor versus vaginal birth, and other factors, on adverse perinatal outcome. For 1384 fetuses delivered after labor, we determined the effect of variables associated with labor on adverse perinatal outcome.Results: The risk of adverse perinatal outcome was lowest with prelabor cesarean section (odds ratio [OR]=0.13) and highest with vaginal birth. For those delivered after labor, labor augmentation (P=.007), birth weight less than 2.8 kg (P=.003), and longer time between pushing and delivery (P<.001) increased the risk, whereas the presence of an experienced clinician at delivery (P=.004) reduced the risk of adverse perinatal outcome.Conclusion: Breech infants at term are best delivered by prelabor cesarean section. [ABSTRACT FROM AUTHOR]

Published
2003

40. Evaluation of an educational program to prevent adolescent pregnancy.

Author

Mitchell-DiCenso A, Thomas BH, Devlin MC, Goldsmith CH, Willan A, Singer J, Marks S, Watters D, and Hewson S

Abstract

The authors evaluated the effectiveness of a school-based sex education program in decreasing rates of sexual intercourse, improving birth control use, and decreasing the incidence of pregnancies among teenagers 16 years of age and younger. Twenty-one schools received either the McMaster Teen Program or the conventional didactic sex education program. Preprogram, the mean age of the students was 12.6 years. There were no statistically significant differences between groups in time to first sexual activity for males, chi 2(1) = 2.93, p = 0.09; time to first sexual activity for females, chi 2(1) = 0.50, p = 0.48; and time to first pregnancy, chi 2(1) = 1.90, p = 0.17. Significantly more experimental group males reported always using birth control at year 1 (difference 8.9%; 95% confidence interval [CI] = 0.4, 17.4). Limitations of the program that may have influenced the results were the exclusion of contraception information and its short duration. [ABSTRACT FROM AUTHOR]

Published
1997
Full Text
View/download PDF

43. Monolayers of valinomycin and its equimolar mixtures with cholesterol and with stearic acid

Author

Hewson S Swift and Herman E Ries

Subjects
Chemistry, Condensation, Analytical chemistry, Mixing (process engineering), Biological membrane, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Biomaterials, Valinomycin, chemistry.chemical_compound, Colloid and Surface Chemistry, Monolayer, Compressibility, Molecule, Organic chemistry, Stearic acid
Abstract

The properties of mixed films of horizontally and vertically oriented molecules bear on many problems in surface chemistry and on the development of models for biological membranes. Pressure-area isotherms for valinomycin, a cyclic dodecadepsipeptide antibiotic, give an extrapolated molecular area of 370 A 2 and an approximate film thickness of 5 A. Horizontal orientation is thus established. Monolayer compressibility is 0.0147 cm/dyn and the collapse pressure is 23 dyn/cm. Cholesterol has a corresponding molecular area of 39 A 2 , a much lower compressibility, 0.0012 cm/dyn, and a higher collapse pressure, 43 dyn/cm. An equimolar mixture of valinomycin and cholesterol gives an isotherm contour that indicates not only the presence of the two components but considerable condensation. A mixed monolayer of valinomycin and stearic acid shows a greater condensation. Electron micrographs of collapsed monolayers of valinomycin and cholesterol demonstrate further the mixing and possible interaction of the two components in the high-pressure region.

Published
1978
Full Text
View/download PDF

48. A controlled trial of nurse practitioners in neonatal intensive care

Author

Mitchell-DiCenso A, Guyatt G, Marrin M, Goeree R, Willan A, Southwell D, Hewson S, Paes B, Rosenbaum P, Hunsberger M, and Andrea Baumann

Subjects
Male, Patient Care Team, Outcome and Process Assessment, Health Care, Intensive Care Units, Neonatal, Surveys and Questionnaires, Pediatrics, Perinatology and Child Health, Infant Mortality, Infant, Newborn, Humans, Female, Nurse Practitioners, Follow-Up Studies
Abstract

Objective. To compare a clinical nurse specialist/neonatal practitioner (CNS/NP) team with a pediatric resident team in the delivery of neonatal intensive care. Design. Randomized, controlled trial. Setting. A 33-bed tertiary-level neonatal intensive care unit. Patients. Of 821 infants admitted to the neonatal intensive care unit between September 1991 and September 1992, 414 were randomized to care by the CNS/NP team, and 407 were randomized to care by the pediatric resident team. Intervention. Infants assigned to the CNS/NP team were cared for by CNS/NPs during the day and by pediatric residents during the night. Infants assigned to the pediatric resident team were cared for by pediatric residents around the clock. Neonatologists supervised both teams. Measures. Outcome measures included mortality; number of neonatal complications; length of stay; quality of care, as assessed by a quantitative indicator condition approach; parent satisfaction with care, measured using the Neonatal Index of Parent Satisfaction; long-term outcomes, measured using the Minnesota Infant Development Inventory; and costs. Results. There were 19 (4.6%) deaths in the CNS/NP group and 24 (5.9%) in the resident group (relative risk [RR], 0.78; confidence interval [CI], 0.43 to 1.40). In the CNS/NP group, 230 (55.6%) neonates had complications, in comparison with 220 (54.1%) in the resident group (RR, 1.03; CI 0.91 to 1.16). Mean lengths of stay were 12.5 days in the CNS/NP group and 11.7 days in the resident group (difference in means, 0.8 days; CI, -1.1 to 2.7). The performance on the indicator conditions was comparable in the two groups except for two instances, jaundice and charting, both of which favored the CNS/NP group. Mean scores on the Neonatal Index of Parent Satisfaction were 140 in the CNS/NP group and 139 in the resident group (difference in means, 1.0; CI, -3.6 to 5.6). In the CNS/NP group, 6 (2.6%) infants performed 30% or more below their age level in the Minnesota Infant Development Inventory, in comparison with 2 (0.9%) in the resident group (RR, 2.87; CI, 0.59 to 14.06) The cost per infant in the CNS/NP group was $14 245 and in the resident group $13 267 (difference in means, $978; CI, -1303.18 to 3259.05). Conclusions. CNS/NP and resident teams are similar with respect to all tested measures of performance. These results support the use of CNS/NPs as an alternative to pediatric residents in delivering care to critically ill neonates.

Catalog

Books, media, physical & digital resources
See catalog results