37 results on '"K. Pedley"'
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2. Paleoseismicity of the western Humps fault on the Emu Plain, North Canterbury, New Zealand
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Russ Van Dissen, N. Khajavi, Andrew Nicol, K. Pedley, Jarg R. Pettinga, Robert Langridge, Ningsheng Wang, Thomas Brough, Timothy Stahl, and Dan Clark
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strike-slip ,geography ,The Humps fault ,geography.geographical_feature_category ,Kaikōura Earthquake ,Geology ,Fault (geology) ,Strike-slip tectonics ,Geophysics ,paleoearthquakes ,Earth and Planetary Sciences (miscellaneous) ,fault trench ,Seismology - Abstract
Supplementary material for article published in New Zealand Journal of Geology and Geophysics “Kaikōura Earthauake: 5 years on Special Issue. Supplementary material contains preferred (Figure S1 and Table S1) and alternate (Figure S2 and Table S2) OxCal age models for the timing of paleoearthquakes and stratigraphy in the McLean-1 trench. Paper details. Brough, T., Nicol, A., Stahl, T., Pettinga, J., Van Dissen, R., Clark, D., Khajavi, N., Pedley, K., Langridge, R., Wang, N., 2021. Paleoseismicity of the western Humps fault on the Emu Plain, North Canterbury, New Zealand. New Zealand Journal of Geology and Geophysics: Kaikoura Earthquake Special Issue. September 2021.
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- 2021
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3. Surface Rupture of Multiple Crustal Faults in the 2016 Mw 7.8 Kaikōura, New Zealand, Earthquake
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K. Pedley, Jesse Kearse, Clark Fenton, Delia Strong, Russ Van Dissen, Garth Archibald, Cameron Asher, Steve Lawson, Adrian Benson, Julie V. Rowland, Simon C. Cox, Robert Zinke, Samuel T. McColl, David Heron, Mark Hemphill-Haley, Andrew Nicol, Duncan Noble, Katrina Sauer, Brendan S. Hall, Tim Kane, Jarg R. Pettinga, John Manousakis, William Ries, Nicola Litchfield, Biljana Lukovic, Jamie Howarth, Suzanne Woelz, Robert Langridge, Jack N. Williams, Ursula Cochran, Caleb Gasston, Alexandra E. Hatem, Mark Stirling, Kelvin Berryman, Dougal Townsend, Timothy Stahl, Virginia Toy, Phaedra Upton, Dan Hale, David J.A. Barrell, Joshu J. Mountjoy, Pilar Villamor, Kate Clark, N. Khajavi, Geoffroy Lamarche, Katie Jones, Timothy A. Little, Philip M. Barnes, and Christopher Madugo
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Surface rupture ,010504 meteorology & atmospheric sciences ,Subduction ,Slip (materials science) ,Surface displacement ,010502 geochemistry & geophysics ,01 natural sciences ,Seafloor spreading ,Tectonics ,Geophysics ,Seismic hazard ,Geochemistry and Petrology ,Seismic moment ,Seismology ,Geology ,0105 earth and related environmental sciences - Abstract
Multiple (>20 \ud >20\ud ) crustal faults ruptured to the ground surface and seafloor in the 14 November 2016 M w \ud Mw\ud 7.8 Kaikōura earthquake, and many have been documented in detail, providing an opportunity to understand the factors controlling multifault ruptures, including the role of the subduction interface. We present a summary of the surface ruptures, as well as previous knowledge including paleoseismic data, and use these data and a 3D geological model to calculate cumulative geological moment magnitudes (M G w \ud MwG\ud ) and seismic moments for comparison with those from geophysical datasets. The earthquake ruptured faults with a wide range of orientations, sense of movement, slip rates, and recurrence intervals, and crossed a tectonic domain boundary, the Hope fault. The maximum net surface displacement was ∼12 m \ud ∼12 m\ud on the Kekerengu and the Papatea faults, and average displacements for the major faults were 0.7–1.5 m south of the Hope fault, and 5.5–6.4 m to the north. M G w \ud MwG\ud using two different methods are M G w \ud MwG\ud 7.7 +0.3 −0.2 \ud 7.7−0.2+0.3\ud and the seismic moment is 33%–67% of geophysical datasets. However, these are minimum values and a best estimate M G w \ud MwG\ud incorporating probable larger slip at depth, a 20 km seismogenic depth, and likely listric geometry is M G w \ud MwG\ud 7.8±0.2 \ud 7.8±0.2\ud , suggests ≤32% \ud ≤32%\ud of the moment may be attributed to slip on the subduction interface and/or a midcrustal detachment. Likely factors contributing to multifault rupture in the Kaikōura earthquake include (1) the presence of the subduction interface, (2) physical linkages between faults, (3) rupture of geologically immature faults in the south, and (4) inherited geological structure. The estimated recurrence interval for the Kaikōura earthquake is ≥5,000–10,000 yrs \ud ≥5,000–10,000 yrs\ud , and so it is a relatively rare event. Nevertheless, these findings support the need for continued advances in seismic hazard modeling to ensure that they incorporate multifault ruptures that cross tectonic domain boundaries.
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- 2018
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4. Preliminary Geometry, Displacement, and Kinematics of Fault Ruptures in the Epicentral Region of the 2016 Mw 7.8 Kaikōura, New Zealand, Earthquake
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Andrew Nicol, Ian Hamling, K. Pedley, Clark Fenton, D. Noble, Bushell T, Timothy Stahl, N. Hyland‐Brook, N. Khajavi, Jarg R. Pettinga, Samuel T. McColl, John Ristau, and Stephen Bannister
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geography ,Geophysics ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Geochemistry and Petrology ,Displacement (orthopedic surgery) ,Kinematics ,Fault (geology) ,010502 geochemistry & geophysics ,01 natural sciences ,Seismology ,Geology ,0105 earth and related environmental sciences - Published
- 2018
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5. The Mw7.8 2016 Kaikōura earthquake
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S. Lawson, Chris Grimshaw, Andrea Barrier, D. Noble, Robert Langridge, F. Fenton, Christopher Madugo, Katrina Sauer, Hale Dd, Timothy Stahl, David J.A. Barrell, Robert Zinke, Clark Fenton, Alex Hatem, Philip M. Barnes, K. Pedley, Delia Strong, Dougal Townsend, Simon C. Cox, Ian Hamling, Timothy A. Little, Pilar Villamor, Samuel T. McColl, Nicola Litchfield, Brendan S. Hall, Marlene Villeneuve, N. Khajavi, Virginia Toy, Biljana Lukovic, Alan Bischoff, Ken Xiansheng Hao, Russ Van Dissen, Caleb Gasston, Tim Kane, Matt Cockcroft, Mark Hemphill-Haley, Jesse Kearse, Adrian Benson, Susanne Woelz, Ursula Cochran, Geoffroy Lamarche, Mark Stirling, Cameron Asher, Z. Juniper, Josh W. Borella, David Heron, Grace Duke, William Ries, Jarg R. Pettinga, Joshu J. Mountjoy, A. Wandres, Andrew Nicol, Jamie Howarth, I. Manousakis, Julie V. Rowland, R. Carne, and Jack N. Williams
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geography ,Surface rupture ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Event (relativity) ,Context (language use) ,Fault (geology) ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,Seismic hazard ,Source model ,Seismology ,Geology ,0105 earth and related environmental sciences ,Civil and Structural Engineering - Abstract
We provide a summary of the surface fault ruptures produced by the Mw7.8 14 November 2016 Kaikōura earthquake, including examples of damage to engineered structures, transportation networks and farming infrastructure produced by direct fault surface rupture displacement. We also provide an overview of the earthquake in the context of the earthquake source model and estimated ground motions from the current (2010) version of the National Seismic Hazard Model (NSHM) for New Zealand. A total of 21 faults ruptured along a c.180 km long zone during the earthquake, including some that were unknown prior to the event. The 2010 version of the NSHM had considered multi-fault ruptures in the Kaikōura area, but not to the degree observed in the earthquake. The number of faults involved a combination of known and unknown faults, a mix of complete and partial ruptures of the known faults, and the non-involvement of a major fault within the rupture zone (i.e. the Hope Fault) makes this rupture an unusually complex event by world standards. However, the strong ground motions of the earthquake are consistent with the high hazard of the Kaikōura area shown in maps produced from the NSHM.
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- 2017
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6. GEOMORPHOLOGY AND ORIGIN OF THE SURFICIAL SEDIMENTS OF THE ST. BERNARD SADDLE, CASS REGION, NEW ZEALAND
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Stefan Winkler, Josh W. Borella, K. Pedley, and Anna Pearson
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Surficial sediments ,Geochemistry ,Geology ,Saddle - Published
- 2020
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7. GEOMORPHIC MAPPING AND ANALYSIS OF GLACIAL LANDFORMS TO UNDERSTAND THE DEVELOPMENT AND DEFINING CHARACTERISTICS OF ‘GLACIAL’ LAKE SPEIGHT IN THE MIDDLE WAIMAKARIRI RIVER OF THE SOUTHERN ALPS, NEW ZEALAND
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Monica Dix, Stefan Winkler, K. Pedley, and Josh W. Borella
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Glacial landform ,Physical geography ,Glacial lake ,Geology - Published
- 2019
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8. GEOMORPHIC MAPPING AND INTERPRETATION OF PARAGLACIAL FAN MORPHOLOGIES IN CASS, NEW ZEALAND
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Josh W. Borella, Kevin Getty, K. Pedley, and Stefan Winkler
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Paleontology ,Paraglacial ,Interpretation (philosophy) ,Geology - Published
- 2019
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9. Strike-slip ground-surface rupture (Greendale Fault) associated with the 4 September 2010 Darfield earthquake, Canterbury, New Zealand
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R. Jongens, Nicola Litchfield, R. Cosgrove, Mark Quigley, H. Mackenzie, L. Moody, R. Nicol, Eric L. Bilderback, Dja Barrell, A. Smith, R. Van Dissen, K. Pedley, Kevin P. Furlong, H. Henham, S. Hemmings-Sykes, John Begg, A. Klahn, D. Noble, Simon C. Cox, E.M.W. Lang, Timothy Stahl, Dougal Townsend, Pilar Villamor, and Brendan Duffy
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Surface rupture ,Sinistral and dextral ,Nouvelle zelande ,Earth and Planetary Sciences (miscellaneous) ,Geology ,Geotechnical Engineering and Engineering Geology ,Strike-slip tectonics ,Surface deformation ,Seismology - Abstract
This paper provides a photographic tour of the ground-surface rupture features of the Greendale Fault, formed during the 4 September 2010 Darfield earthquake. The fault, previously unknown, produced at least 29.5 km of strike-slip surface deformation of right-lateral (dextral) sense. Deformation, spread over a zone between 30 and 300 m wide, consisted mostly of horizontal flexure with subsidiary discrete shears, the latter only prominent where overall displacement across the zone exceeded about 1.5 m. A remarkable feature of this event was its location in an intensively farmed landscape, where a multitude of straight markers, such as fences, roads and ditches, allowed precise measurements of offsets, and permitted well-defined limits to be placed on the length and widths of the surface rupture deformation.
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- 2011
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10. Surface rupture of the Greendale Fault during the Darfield (Canterbury) earthquake, New Zealand
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D. Noble, Timothy Stahl, Kevin P. Furlong, R. Jongens, Brendan Duffy, H. Mackenzie, K. Pedley, Dougal Townsend, Nicola Litchfield, A. Klahn, John Begg, S. Hornblow, Eric L. Bilderback, Pilar Villamor, Simon C. Cox, J. Claridge, A. Smith, R. Nicol, R. Van Dissen, W. Ries, Robert Langridge, Dja Barrell, and Mark Quigley
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Surface rupture ,geography ,geography.geographical_feature_category ,Sinistral and dextral ,Deformation (mechanics) ,Echelon formation ,Vertical displacement ,Fault (geology) ,Geotechnical Engineering and Engineering Geology ,Displacement (vector) ,Seismology ,Geology ,Civil and Structural Engineering - Abstract
The Mw 7.1 Darfield (Canterbury) earthquake of 4 September 2010 (NZST) was the first earthquake in New Zealand to produce ground-surface fault rupture since the 1987 Edgecumbe earthquake. Surface rupture of the previously unrecognised Greendale Fault during the Darfield earthquake extends for at least 29.5 km and comprises an en echelon series of east-west striking, left-stepping traces. Displacement is predominantly dextral strike-slip, averaging ~2.5 m, with maxima of ~5 m along the central part of the rupture. Maximum vertical displacement is ~1.5 m, but generally < 0.75 m. The south side of the fault has been uplifted relative to the north for ~80% of the rupture length, except at the eastern end where the north side is up. The zone of surface rupture deformation ranges in width from ~30 to 300 m, and comprises discrete shears, localised bulges and, primarily, horizontal dextral flexure. At least a dozen buildings were affected by surface rupture, but none collapsed, largely because most of the buildings were relatively flexible and robust timber-framed structures and because deformation was distributed over tens to hundreds of metres width. Many linear features, such as roads, fences, power lines, and irrigation ditches were offset or deformed by fault rupture, providing markers for accurate determinations of displacement.
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- 2010
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11. Tectonic and geological framework for gas hydrates and cold seeps on the Hikurangi subduction margin, New Zealand
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Stuart Henrys, Philip M. Barnes, Ingo Pecher, K. Pedley, G L Netzeband, Jens Greinert, Jörg Bialas, Gareth Crutchley, Geoffroy Lamarche, and Joshu J. Mountjoy
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geography ,Décollement ,geography.geographical_feature_category ,Accretionary wedge ,Subduction ,Hikurangi Margin ,Seamount ,Anticline ,Geology ,Oceanography ,Seafloor spreading ,Geochemistry and Petrology ,Thrust fault ,Petrology ,Seismology - Abstract
The imbricated frontal wedge of the central Hikurangi subduction margin is characteristic of wide (ca. 150 km), poorly drained and over pressured, low taper (not, vert, similar 4°) thrust systems associated with a relatively smooth subducting plate, a thick trench sedimentary sequence (not, vert, similar 3–4 km), weak basal decollement, and moderate convergence rate (not, vert, similar 40 mm/yr). New seismic reflection and multibeam bathymetric data are used to interpret the regional tectonic structures, and to establish the geological framework for gas hydrates and fluid seeps. We discuss the stratigraphy of the subducting and accreting sequences, characterize stratigraphically the location of the interplate decollement, and describe the deformation of the upper plate thrust wedge together with its cover sequence of Miocene to Recent shelf and slope basin sediments. We identify approximately the contact between an inner foundation of deforming Late Cretaceous and Paleogene rocks, in which widespread out-of-sequence thrusting occurs, and a 65–70 km-wide outer wedge of late Cenozoic accreted turbidites. Although part of a seamount ridge is presently subducting beneath the deformation front at the widest part of the margin, the morphology of the accretionary wedge indicates that frontal accretion there has been largely uninhibited for at least 1–2 Myr. This differs from the offshore Hawkes Bay sector of the margin to the north where a substantial seamount with up to 3 km of relief has been subducted beneath the lower margin, resulting in uplift and complex deformation of the lower slope, and a narrow (10–20 km) active frontal wedge. Five areas with multiple fluid seep sites, referred to informally as Wairarapa, Uruti Ridge, Omakere Ridge, Rock Garden, and Builders Pencil, typically lie in 700–1200 m water depth on the crests of thrust-faulted, anticlinal ridges along the mid-slope. Uruti Ridge sites also lie in close proximity to the eastern end of a major strike-slip fault. Rock Garden sites lie directly above a subducting seamount. Structural permeability is inferred to be important at all levels of the thrust system. There is a clear relationship between the seeps and major seaward-vergent thrust faults, near the outer edge of the deforming Cretaceous and Paleogene inner foundation rocks. This indicates that thrust faults are primary fluid conduits and that poor permeability of the Cretaceous and Paleogene inner foundation focuses fluid flow to its outer edge. The sources of fluids expelling at active seep sites along the middle slope may include the inner parts of the thrust wedge and subducting sediments below the decollement. Within anticlinal ridges beneath the active seep sites there is a conspicuous break in the bottom simulating reflector (BSR), and commonly a seismically-resolvable shallow fault network through which fluids and gas percolate to the seafloor. No active fluid venting has yet been recognized over the frontal accretionary wedge, but the presence of a widespread BSR, an extensive protothrust zone (> 200 km by 20 km) in the Hikurangi Trough, and two unconfirmed sites of possible previous fluid expulsion, suggest that the frontal wedge could be actively dewatering. There are presently no constraints on the relative fluid flux between the frontal wedge and the active mid-slope fluid seeps. Article Outline
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- 2010
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12. Seafloor structural geomorphic evolution of the accretionary frontal wedge in response to seamount subduction, Poverty Indentation, New Zealand
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Jarg R. Pettinga, Philip M. Barnes, K. Pedley, and Keith B. Lewis
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Canyon ,geography ,geography.geographical_feature_category ,Continental shelf ,Hikurangi Margin ,Seamount ,Geology ,Oceanography ,Seafloor spreading ,Continental margin ,Geochemistry and Petrology ,Thrust fault ,Geomorphology ,Forearc - Abstract
High quality swath bathymetry and seismic reflection data reveal that the steep forearc slope along the northern sector of the obliquely convergent Hikurangi subduction zone is characteristic of non-accretionary and tectonically eroding continental margins, with reduced sediment supply in the trench relative to further south, and the presence of subducting seamount relief on the Hikurangi Plateau. These seamounts influence the subduction process and the structurally-driven geomorphic development of the over-riding margin of the Australian Plate frontal wedge. The origin of the Poverty Indentation, on the inboard trench slope, is attributed to multiple seamount impacts over the last c. 1 Myr period, accompanied by canyon incision, thrust fault propagation into the trench fill, and numerous large-scale gravitational collapse structures with multiple debris flow and avalanche deposits ranging in downslope length from a few hundred metres to more than 40 km. The indentation is directly offshore of the Waipaoa River which is currently estimated to have a high sediment yield into the marine system. The Poverty Canyon stretches 70 km from the continental shelf edge directly offshore from the Waipaoa to the trench floor, incising into the axis of the indentation. The sediment delivered to the margin from the Waipaoa catchment and elsewhere during sea-level high-stands, including the Holocene, has remained largely trapped in a large depocentre on the Poverty shelf, while during low-stand cycles, sediment bypassed the shelf to develop a prograding clinoform sequence out onto the upper slope. The formation of the indentation and the development of the upper branches of the Poverty Canyon system has led to the progressive removal of a substantial part of this prograding wedge by mass movements and gully incision. Sediment has also accumulated in the head of the Poverty Canyon and episodic mass flows contribute significantly to continued modification of the indentation by driving canyon incision and triggering instability in the adjacent slopes. Prograding clinoforms lying seaward of active faults beneath the shelf, and overlying a buried inactive thrust system beneath the upper slope, reveal a history of deformation accompanied by the creation of accommodation space. The middle to lower Poverty Canyon represents a structural transition zone within the indentation coincident with the indentation axis. The lower to mid-slope south of the canyon conforms more closely to a classic accretionary slope deformation style with a series of east-facing thrust-propagated asymmetric anticlines, separated by early-stage slope basins. North of the canyon system, seamount impact has resulted in frontal tectonic erosion associated with the development of an over-steepened lower to mid-slope margin, fault reactivation and structural inversion and over-printing.
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- 2010
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13. A METHODOLOGY FOR INTEGRATING A VIRTUAL FIELD TRIP WITH INTERACTIVE LEARNING INTO A TERTIARY CURRICULUM
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Clark Fenton, K. Pedley, Alistair J. Davies, Nathaly Reyna, Tim Davies, Pete Sommerville, Barrie Matthews, Erik Brogt, Thomas Wilson, Samuel J. Hampton, Alison Jolley, Shelley Hersey, and Ben Kennedy
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Engineering ,Multimedia ,business.industry ,Virtual field ,computer.software_genre ,business ,computer ,Curriculum ,Interactive Learning - Published
- 2016
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14. A structured competency based training programme for junior trainees in emergency medicine: the 'Dundee Model'
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S Thakore, Ronald J Cook, and D K Pedley
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Models, Educational ,Medical education ,medicine.medical_specialty ,Educational measurement ,business.industry ,education ,General Medicine ,Critical Care and Intensive Care Medicine ,Competency-Based Education ,humanities ,Teaching hospital ,Scotland ,Education, Medical, Graduate ,Emergency medicine ,Emergency Medicine ,Medical training ,Humans ,Medicine ,Original Article ,Educational Measurement ,Emergency Service, Hospital ,Hospitals, Teaching ,business ,Training programme - Abstract
Recent changes in medical training prompted by Modernising Medical Careers and the New Deal requires a more structured, competency based training programme. This paper describes the development of such a programme in an emergency medicine department of a teaching hospital. It describes the process of design and the various aspects incorporated to develop a balanced system of training, appraisal, and assessment.
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- 2006
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15. Prospective observational cohort study of time saved by prehospital thrombolysis for ST elevation myocardial infarction delivered by paramedics
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M C Jones, Kim Bissett, David K Pedley, Ian Golding, G. P. Mcneill, Stuart D. Pringle, Elizabeth M Connolly, Carol G Goodman, and T. H. Pringle
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Emergency Medical Services ,medicine.medical_specialty ,Time Factors ,medicine.medical_treatment ,Myocardial Infarction ,Rural Health ,Cohort Studies ,Catchment Area, Health ,Fibrinolysis ,medicine ,Emergency medical services ,Humans ,Thrombolytic Therapy ,Hospital Mortality ,Prospective Studies ,Letters ,cardiovascular diseases ,Myocardial infarction ,Hospitals, Teaching ,Intensive care medicine ,Prospective cohort study ,General Environmental Science ,medicine.diagnostic_test ,business.industry ,ST elevation ,Urban Health ,General Engineering ,General Medicine ,Thrombolysis ,medicine.disease ,Transportation of Patients ,Scotland ,Papers ,Emergency medicine ,General Earth and Planetary Sciences ,business ,Electrocardiography ,Cohort study - Abstract
To evaluate a system of prehospital thrombolysis, delivered by paramedics, in meeting the national service framework's targets for the management of acute myocardial infarction.Prospective observational cohort study comparing patients with suspected acute myocardial infarction considered for thrombolysis in the prehospital environment with patients treated in hospital.The catchment area of a large teaching hospital, including urban and rural areas.201 patients presenting concurrently over a 12 month period who had changes to the electrocardiogram that were diagnostic of acute myocardial infarction or who received thrombolysis for suspected acute myocardial infarction.Time from first medical contact to initiation of thrombolysis (call to needle time), number of patients given thrombolysis appropriately, and all cause mortality in hospital.The median call to needle time for patients treated before arriving in hospital (n=28) was 52 (95% confidence interval 41 to 62) minutes. Patients from similar rural areas who were treated in hospital (n=43) had a median time of 125 (104 to 140) minutes. This represents a median time saved of 73 minutes (P0.001). Sixty minutes after medical contact 64% of patients (18/28) treated before arrival in hospital had received thrombolysis; this compares with 4% of patients (2/43) in a cohort from similar areas. Median call to needle time for patients from urban areas (n=107) was 80 (78 to 93) minutes. Myocardial infarction was confirmed in 89% of patients (25/28) who had received prehospital thrombolysis; this compares with 92% (138/150) in the two groups of patients receiving thrombolysis in hospital.Thrombolysis delivered by paramedics with support from the base hospital can meet the national targets for early thrombolysis. The system has been shown to work well and can be introduced without delay.
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- 2003
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16. Mobile telemetry for pre-hospital thrombolysis: problems and solutions
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David K Pedley, Stephen Beedie, and James Ferguson
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Emergency Medical Services ,020205 medical informatics ,medicine.medical_treatment ,Health Informatics ,02 engineering and technology ,Cohort Studies ,03 medical and health sciences ,0302 clinical medicine ,Signal strength ,Telemetry ,0202 electrical engineering, electronic engineering, information engineering ,Medicine ,Humans ,Thrombolytic Therapy ,030212 general & internal medicine ,business.industry ,Thrombolysis ,medicine.disease ,Telemedicine ,Pre hospital thrombolysis ,Equipment failure ,Scotland ,Median time ,Electrocardiography, Ambulatory ,Medical emergency ,business - Abstract
In the Angus region of Scotland, we have used mobile telemetry to facilitate pre-hospital thrombolysis by paramedic staff. An initial survey demonstrated that connection could be achieved in all but three locations. In the first year of operation, 229 contacts were received. Communication between the ambulance and the base station failed on four occasions (2%). Problems with transmission of an electrocardiogram (ECG) were encountered on 37 occasions (16%). The median time for acquisition and transmission of an ECG was 22 min. This compares with a median time of 59 min for first ECG in a control group from similar locations, who were assessed in hospital. Telemetry offers essential back-up to paramedics adopting a challenging and extended role. Strategies can be developed to deal with signal strength and equipment failure.
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- 2005
17. Heterogeneity in nuclear transport does not affect the timing of DNA synthesis in quiescent mammalian nuclei induced to replicate in Xenopus egg extracts
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W H, Sun, M, Hola, N, Baldwin, K, Pedley, and R F, Brooks
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Cell Nucleus ,DNA Replication ,Microscopy, Fluorescence ,Xenopus ,Molecular Sequence Data ,Animals ,Nuclear Proteins ,Amino Acid Sequence ,Original Articles ,Nucleoplasmins ,Phosphoproteins ,Ovum - Abstract
Intact G(0) nuclei from quiescent mammalian cells initiate DNA synthesis asynchronously in Xenopus egg extracts, despite exposure to the same concentration of replication factors. This indicates that individual nuclei differ in their ability to respond to the inducers of DNA replication. Since the induction of DNA synthesis requires the accumulation of replication factors by active nuclear transport, any variation in the rate of transport among nuclei could contribute to the variability of DNA replication. Using the naturally fluorescent protein allophycocyanin (APC) coupled with the nuclear localization sequence (NLS) of SV40 T antigen, as a marker of nuclear uptake, we show here that individual G(0) nuclei differ in their rate of transport over a range of more than 20‐fold. Surprisingly, this variation has no direct influence on the timing or extent of DNA synthesis. Similar results were obtained by monitoring the uptake of nucleoplasmin, a nuclear protein present at high levels in egg extracts. These experiments show that the initiation of DNA synthesis is not driven merely by the accumulation of replication factors to some threshold concentration. Instead, some other explanation is needed to account for the timing of initiation.
- Published
- 2001
18. Abstract-to-publication ratio for papers presented at scientific meetings: a quality marker for UK emergency medicine research
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Craig D Macmillan, David K Pedley, Anthony K Moore, and Ronald J Cook
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Publishing ,medicine.medical_specialty ,Abstracting and Indexing ,business.industry ,Research ,Accident and emergency ,Short Report ,Alternative medicine ,MEDLINE ,General Medicine ,Congresses as Topic ,Critical Care and Intensive Care Medicine ,United Kingdom ,Emergency medicine ,Emergency Medicine ,medicine ,Humans ,Periodicals as Topic ,Medline database ,business ,Retrospective Studies - Abstract
Objectives: To determine the publication rate of abstracts presented by UK emergency physicians at major emergency medicine meetings, and to identify the site of publication of papers. Method: All abstracts presented to the annual scientific meetings of both the British Association of Emergency Medicine and the Faculty of Accident and Emergency Medicine between 2001 and 2002 were identified retrospectively from conference programmes. To identify whether the work relating to the abstract had been published in a peer-reviewed journal, the Medline database (Ovid interface) was searched using the first and last authors as well as key words from the abstract. Results: Of the 404 abstracts identified, 124 (30%) had been published as full articles. For abstracts presented in the oral sessions, 83 (57%) resulted in publication. A range of journals accepted papers for publication. Conclusion: The abstract-to-publication ratio for UK emergency medicine is lower than for other specialties, but broadly similar to emergency medicine in the US and Australia.
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- 2007
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19. Removal of C-spine protection by A&E triage nurses: a prospective trial of a clinical decision making instrument
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M Johnston, E Pitt, A Nelson, D K Pedley, and M Cumming
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Adult ,Male ,medicine.medical_specialty ,Adolescent ,Decision Making ,Short Report ,Nursing assessment ,Critical Care and Intensive Care Medicine ,Decision Support Techniques ,Clinical decision making ,Humans ,Medicine ,Prospective Studies ,Child ,Prospective cohort study ,Device Removal ,Aged ,Aged, 80 and over ,business.industry ,Protective Devices ,General Medicine ,Middle Aged ,medicine.disease ,Triage ,Spinal Injuries ,Prospective trial ,Radiological weapon ,Emergency medicine ,Emergency Medicine ,Female ,Cervical collar ,Medical emergency ,Medical assessment ,Emergency Service, Hospital ,business - Abstract
To investigate if triage nurses could safely apply a set of clinical criteria, removing hard collars and spinal boards at initial triage assessment.The Nexus clinical decision rules were applied by trained triage nurses to patients who attended the department with cervical collars and/or on spinal boards. Patients were excluded if they were felt to be in need of immediate medical assessment. Data were collected on the time to nursing assessment, time to medical assessment and time spent restrained. Patients were followed up until discharge and their radiological diagnosis confirmed. Hospital records were checked to ensure that no patients re-presented with injuries that had been missed at initial assessment.In total, 112 patients were included in the study. Clinical criteria were met in 59 patients and their collar removed at triage assessment. For low risk patients, this reflects a mean reduction in time spent restrained of 23.3 minutes (p0.005; 95% confidence interval 20.18 to 26.54). No patient who had a collar removed was found to have a significant injury.Simple criteria can be applied by accident and emergency triage nurses to allow safe removal of cervical collars and spinal boards. The reduced time patients spent immobilised represents an important improvement in patient care.
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- 2006
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20. Difference in injury pattern between drivers and front seat passengers involved in road traffic accidents in Scotland
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S Thakore and D K Pedley
- Subjects
Automobile Driving ,Thoracic Injuries ,Short Report ,Poison control ,Critical Care and Intensive Care Medicine ,Occupational safety and health ,Risk Factors ,Injury prevention ,Humans ,Medicine ,Road traffic ,Front (military) ,Lumbar Vertebrae ,business.industry ,Protective Devices ,digestive, oral, and skin physiology ,Accidents, Traffic ,Human factors and ergonomics ,General Medicine ,Crash test ,Scotland ,Spinal Injuries ,Cervical Vertebrae ,Emergency Medicine ,Wounds and Injuries ,Body region ,business ,human activities ,Demography - Abstract
Objectives: To investigate the frequency and pattern of injury in front seat passengers as compared with drivers, in Scotland. Methods: Using the Scottish Trauma Audit Group (STAG) database from 1994 to 2000, a search for injuries to eight anatomical body regions was performed. Injuries were identified and selected by their abbreviated injury score code. A comparison of injury frequency between drivers and front seat passengers was then made. Results: There were 4189 drivers and 954 front seat passengers included in the study. Mortality was higher in the “front seat passengers” group (6.6% compared with 5.3% p = 0.13). Seven of the eight body regions selected showed higher rates of injury in front seat passengers. There were significantly more injuries to cervical spine (6.0% compared with 3.3% p⩽0.001), chest (41.4% compared with 29.0% p⩽0.001), and lumber spine (7.4% compared with 5.2% p⩽0.001) in front seat passengers. Conclusions: Front seat passengers are at increased risk of injury relative to drivers in actual road traffic accidents as recorded in the STAG database. This contradicts crash test data, which suggest drivers are less well protected than front seat passengers in laboratory conditions.
- Published
- 2004
- Full Text
- View/download PDF
21. O-086. Investigation of possible damage to the cytoskeletal elements of the human oocyte following ICSI
- Author
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J.G. Grudzinskas, C. Wilson, F.F. Norman, K. Pedley, R.K. IIes, A.M. Lower, and S.M. Hawes
- Subjects
medicine.anatomical_structure ,Reproductive Medicine ,Chemistry ,Rehabilitation ,medicine ,Obstetrics and Gynecology ,Oocyte ,Cytoskeleton ,Cell biology - Published
- 1997
- Full Text
- View/download PDF
22. The replication capacity of intact mammalian nuclei in Xenopus egg extracts declines with quiescence, but the residual DNA synthesis is independent of Xenopus MCM proteins.
- Author
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W, Sun, M, Hola, K, Pedley, S, Tada, J, Blow J, T, Todorov I, E, Kearsey S, and F, Brooks R
- Abstract
In eukaryotes, the initiation of DNA synthesis requires the assembly of a pre-replicative complex (pre-RC) at origins of replication. This involves the sequential binding of ORC (origin-recognition-complex), Cdc6 and MCM proteins, a process referred to as licensing. After origin firing, the Cdc6 and MCM proteins dissociate from the chromatin, and do not rebind until after the completion of mitosis, thereby restricting replication to a single round in each cell cycle. Although nuclei normally become licensed for replication as they enter G(1), the extent to which the license is retained when cells enter the quiescent state (G(0)) is controversial. Here we show that the replication capacity of nuclei from Swiss 3T3 cells, in Xenopus egg extracts, is not lost abruptly with the onset of quiescence, but instead declines gradually. The decline in replication capacity, which affects both the number of nuclei induced to replicate and their subsequent rate of DNA synthesis, is accompanied by a fall in the level of chromatin-bound MCM2. When quiescent nuclei are incubated in egg extracts, they do not bind further MCMs unless the nuclei are first permeabilized. The residual replication capacity of intact nuclei must therefore be dependent on the remaining endogenous MCMs. Although high levels of Cdk activity are known to block MCM binding, we show that the failure of intact nuclei in egg extracts to increase their bound MCMs is not due to their uptake and accumulation of Cdk complexes. Instead, the failure of binding must be due to exclusion of some other binding factor from the nucleus, or to the presence within nuclei of an inhibitor of binding other than Cdk activity. In contrast to the situation in Xenopus egg extracts, following serum stimulation of intact quiescent cells, the level of bound MCMs does increase before the cells reach S phase, without any disruption of the nuclear envelope.
- Published
- 2000
23. Hypodermic Injections of Cocaine, etc., for Local Anaesthesia, and the Anaesthetics Bill
- Author
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J. K. Pedley
- Subjects
business.industry ,Anesthesia ,Correspondence ,General Engineering ,General Earth and Planetary Sciences ,Medicine ,General Medicine ,business ,General Environmental Science - Published
- 1910
- Full Text
- View/download PDF
24. Difference in injury pattern between drivers and front seat passengers involved in road traffic accidents in Scotland.
- Author
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K, Pedley D and S, Thakore
- Abstract
OBJECTIVES: To investigate the frequency and pattern of injury in front seat passengers as compared with drivers, in Scotland. METHODS: Using the Scottish Trauma Audit Group (STAG) database from 1994 to 2000, a search for injuries to eight anatomical body regions was performed. Injuries were identified and selected by their abbreviated injury score code. A comparison of injury frequency between drivers and front seat passengers was then made. RESULTS: There were 4189 drivers and 954 front seat passengers included in the study. Mortality was higher in the "front seat passengers" group (6.6% compared with 5.3% p = 0.13). Seven of the eight body regions selected showed higher rates of injury in front seat passengers. There were significantly more injuries to cervical spine (6.0% compared with 3.3% p</=0.001), chest (41.4% compared with 29.0% p</=0.001), and lumber spine (7.4% compared with 5.2% p</=0.001) in front seat passengers. CONCLUSIONS: Front seat passengers are at increased risk of injury relative to drivers in actual road traffic accidents as recorded in the STAG database. This contradicts crash test data, which suggest drivers are less well protected than front seat passengers in laboratory conditions.
- Published
- 2004
25. Perspectives on Support Material for Referrals to Cochlear Implantation Teams.
- Author
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Mashal M, Au A, Leigh J, Távora-Vieira D, Wedekind A, Pedley K, Swiderski N, Chester-Browne R, Balke C, Brew J, Arkcoll A, Dahm MR, and Boisvert I
- Subjects
- Adult, Australia, Humans, Referral and Consultation, Cochlear Implantation, Cochlear Implants, Hearing Loss
- Abstract
Purpose: This study used a collaborative approach to explore the needs, barriers, and facilitators to developing cochlear implant referral information material that would be valuable for hard of hearing adults and referring audiologists., Method: During the development of a prototype referral aid to be used within the Australian context, a multistage qualitative study was conducted using a consultative process, informal and semistructured interviews, as well as online surveys. A deductive directed content analysis approach was applied to assess respondents' perspectives. A total of 106 participants (37 hard of hearing adults and 69 audiologists) were involved across the multiple phases of this study., Results: Referral practices for the evaluation of cochlear implantation candidacy in Australia are highly inconsistent, supporting the need to streamline referral information. The following facilitators were identified to support the development of referral material: appropriate content, perceived patient benefit, and objectivity. Areas for improvement related to the broadness of the content, impact on professional identity, and accessibility., Conclusions: Practical insight from patients and referrers can inform the development of patient-facing material related to cochlear implant referrals. Streamlining information used in educational material could alleviate confusion inherent to varied health literacy levels and support patients in making informed decisions related to pursuing, or not, cochlear implantation candidacy evaluation services.
- Published
- 2022
- Full Text
- View/download PDF
26. Nutrition in New Zealand: Can the Past Offer Lessons for the Present and Guidance for the Future?
- Author
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Coad J and Pedley K
- Subjects
- Food Industry, Food Supply legislation & jurisprudence, Humans, Malnutrition epidemiology, New Zealand epidemiology, Noncommunicable Diseases epidemiology, Nutrition Policy legislation & jurisprudence, Nutrition Policy trends, Nutritional Status, Policy Making, Public Health
- Abstract
Over the last century, nutrition research and public health in New Zealand have been inspired by Dr Muriel Bell, the first and only state nutritionist. Some of her nutritional concerns remain pertinent today. However, the nutritional landscape is transforming with extraordinary changes in the production and consumption of food, increasing demand for sustainable and healthy food to meet the requirements of the growing global population and unprecedented increases in the prevalence of both malnutrition and noncommunicable diseases. New Zealand's economy is heavily dependent on agrifoods, but there is a need to integrate interactions between nutrition and food-related disciplines to promote national food and nutrition security and to enhance health and well-being. The lack of integration between food product development and health is evident in the lack of investigation into possible pathological effects of food additives. A national coherent food strategy would ensure all components of the food system are optimised and that strategies to address the global syndemic of malnutrition and climate change are prioritised. A state nutritionist or independent national nutrition advocacy organisation would provide the channel to communicate nutrition science and compete with social media, lead education priorities and policy development, engage with the food industry, facilitate collaboration between the extraordinary range of disciplines associated with food production and optimal health and lead development of a national food strategy.
- Published
- 2020
- Full Text
- View/download PDF
27. Novel Sources of Wheat Head Blast Resistance in Modern Breeding Lines and Wheat Wild Relatives.
- Author
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Cruppe G, Cruz CD, Peterson G, Pedley K, Asif M, Fritz A, Calderon L, Lemes da Silva C, Todd T, Kuhnem P, Singh PK, Singh RP, Braun HJ, Barma NCD, and Valent B
- Subjects
- Asia, Bolivia, Brazil, Breeding, Plant Diseases microbiology, Disease Resistance genetics, Triticum genetics, Triticum microbiology
- Abstract
Wheat head blast (WHB), caused by the fungus Magnaporthe oryzae pathotype triticum , is a devastating disease affecting South America and South Asia. Despite 30 years of intensive effort, the 2N
V S translocation from Aegilops ventricosa contains the only useful source of resistance to WHB effective against M. oryzae triticum isolates. The objective of this study was to identify non-2NV S sources of resistance to WHB among elite cultivars, breeding lines, landraces, and wild-relative accessions. Over 780 accessions were evaluated under field and greenhouse conditions in Bolivia, greenhouse conditions in Brazil, and at two biosafety level-3 laboratories in the United States. The M. oryzae triticum isolates B-71 (2012), 008 (2015), and 16MoT001 (2016) were used for controlled experiments, while isolate 008 was used for field experiments. Resistant and susceptible checks were included in all experiments. Under field conditions, susceptible spreaders were inoculated at the tillering stage to guarantee sufficient inoculum. Disease incidence and severity were evaluated as the average rating for each 1-m-row plot. Under controlled conditions, heads were inoculated after full emergence and individually rated for percentage of diseased spikelets. The diagnostic marker Ventriup-LN2 was used to test for the presence of the 2NV S translocation. Four non-2NV S spring wheat International Maize and Wheat Improvement Center breeding lines (CM22, CM49, CM52, and CM61) and four wheat wild-relatives ( A. tauschii TA10142, TA1624, TA1667, and TA10140) were identified as resistant (<5% of severity) or moderately resistant (5 to <25% severity) to WHB. Experiments conducted at the seedling stage showed little correlation with disease severity at the head stage. M. oryzae triticum isolate 16MoT001 was significantly more aggressive against 2NV S-based varieties. The low frequency of WHB resistance and the increase in aggressiveness of newer M. oryzae triticum isolates highlight the threat that the disease poses to wheat production worldwide and the urgent need to identify and characterize new resistance genes that can be used in breeding for durably resistant varieties.- Published
- 2020
- Full Text
- View/download PDF
28. The Lolium Pathotype of Magnaporthe oryzae Recovered from a Single Blasted Wheat Plant in the United States.
- Author
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Farman M, Peterson G, Chen L, Starnes J, Valent B, Bachi P, Murdock L, Hershman D, Pedley K, Fernandes JM, and Bavaresco J
- Abstract
Wheat blast is a devastating disease that was first identified in Brazil and has subsequently spread to surrounding countries in South America. In May 2011, disease scouting in a University of Kentucky wheat trial plot in Princeton, KY identified a single plant with disease symptoms that differed from the Fusarium head blight that was present in surrounding wheat. The plant in question bore a single diseased head that was bleached yellow from a point about one-third up the rachis to the tip. A gray mycelial mass was observed at the boundary of the healthy tissue and microscopic examination of this material revealed pyriform spores consistent with a Magnaporthe sp. The pathogen was subsequently identified as Magnaporthe oryzae through amplification and sequencing of molecular markers, and genome sequencing revealed that the U.S. wheat blast isolate was most closely related to an M. oryzae strain isolated from annual ryegrass in 2002 and quite distantly related to M. oryzae strains causing wheat blast in South America. The suspect isolate was pathogenic to wheat, as indicated by growth chamber inoculation tests. We conclude that this first occurrence of wheat blast in the United States was most likely caused by a strain that evolved from an endemic Lolium-infecting pathogen and not by an exotic introduction from South America. Moreover, we show that M. oryzae strains capable of infecting wheat have existed in the United States for at least 16 years. Finally, evidence is presented that the environmental conditions in Princeton during the spring of 2011 were unusually conducive to the early production of blast inoculum.
- Published
- 2017
- Full Text
- View/download PDF
29. Iron deficiency and iron deficiency anemia in women.
- Author
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Coad J and Pedley K
- Subjects
- Anemia, Iron-Deficiency epidemiology, Female, Humans, Risk, Anemia, Iron-Deficiency etiology, Iron metabolism
- Abstract
Iron deficiency is one of the most common nutritional problems in the world and disproportionately affects women and children. Stages of iron deficiency can be characterized as mild deficiency where iron stores become depleted, marginal deficiency where the production of many iron-dependent proteins is compromised but hemoglobin levels are normal and iron deficiency anemia where synthesis of hemoglobin is decreased and oxygen transport to the tissues is reduced. Iron deficiency anemia is usually assessed by measuring hemoglobin levels but this approach lacks both specificity and sensitivity. Failure to identify and treat earlier stages of iron deficiency is concerning given the neurocognitive implications of iron deficiency without anemia. Most of the daily iron requirement is derived from recycling of senescent erythrocytes by macrophages; only 5-10 % comes from the diet. Iron absorption is affected by inhibitors and enhancers of iron absorption and by the physiological state. Inflammatory conditions, including obesity, can result in iron being retained in the enterocytes and macrophages causing hypoferremia as a strategic defense mechanism to restrict iron availability to pathogens. Premenopausal women usually have low iron status because of iron loss in menstrual blood. Conditions which further increase iron loss, compromise absorption or increase demand, such as frequent blood donation, gastrointestinal lesions, athletic activity and pregnancy, can exceed the capacity of the gastrointestinal tract to upregulate iron absorption. Women of reproductive age are at particularly high risk of iron deficiency and its consequences however there is a controversial argument that evolutionary pressures have resulted in an iron deficient phenotype which protects against infection.
- Published
- 2014
- Full Text
- View/download PDF
30. Urea Output by L3 Teladorsagia circumcincta and some Properties of Two Urea Producing Enzymes.
- Author
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Muhamad N, Walker L, Simcock D, Pedley K, Simpson H, and Brown S
- Abstract
Background: Like several other parasites, Teladorsagia circumcincta secretes or excretes urea, but neither the rate of efflux nor the possible metabolic sources of the urea has been considered., Methods: Parasites were maintained by passage through sheep. Urea efflux was measured using phenol/hypochlorite after treatment with urea aminohydrolase. The kinetics of creatine amidinohydrolase and arginine amidinohydrolase were characterised by coupling the reactions with urea aminohydrolase and glutamate dehydrogenase., Results: Infective L3 T. circumcincta secreted or excreted urea at 25% of the rate of NH3/NH4 (+). The rate of urea efflux was about 84 pmol h(-1) (10(3) larvae)(-1) over 4 hours, corresponding to about 11 nmol h(-1) mg(-1) protein. We could not detect urea aminohydrolase activity, but urea production by both creatine amidinohydrolase and arginine amidinohydrolase could be detected. The apparent K m and V max of creatine amidinohydrolase were 1.1 mM and 48 nmol h(-1) mg(-1) protein, respectively, and the activity was greatest at pH 8. The apparent K m and V max of arginine amidinohydrolase were 0.7 mM and 62 nmol h(-1) mg(-1) protein, respectively, and the activity was greatest at pH 7.9., Conclusion: The activity of creatine amidinohydrolase and arginine amidinohydrolase was sufficient to account for the rate of urea secretion or excretion.
- Published
- 2013
31. Cochlear implant outcomes in adults and adolescents with early-onset hearing loss.
- Author
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Caposecco A, Hickson L, and Pedley K
- Subjects
- Adolescent, Adult, Age Factors, Age of Onset, Aged, Child, Child, Preschool, Female, Health Surveys, Humans, Male, Middle Aged, Prognosis, Retrospective Studies, Self Report, Young Adult, Cochlear Implantation rehabilitation, Hearing Loss, Bilateral rehabilitation, Hearing Loss, Sensorineural rehabilitation, Patient Satisfaction, Speech Perception
- Abstract
Objectives: The aims of the study were to investigate (1) speech perception outcomes in people with an early-onset hearing loss (HL) who received a cochlear implant as an adolescent or adult, (2) prognostic factors associated with positive speech perception outcomes, and (3) self-report outcomes in these participants., Design: Outcomes for 38 implant recipients with a Nucleus device were investigated retrospectively. All participants were diagnosed with a bilateral HL at age #3 yr and were implanted at age 14 yr or older. Nineteen participants had confirmed bilateral, severe to profound HL at age #12 mo (prelingual); nine had confirmed bilateral, severe to profound HL at age.12 mo and #3 yr (perilingual); and the remaining 10 had a diagnosis of bilateral sensorineural HL at age #3 yr which progressed to severe to profound HL after 3 yrs of age (progressive). There were 24 females and 14 males, and the average age at implantation was 33 yr (range 5 14-65 yr). Closed-set and open-set speech perception tests administered pre- and postimplant were analyzed for all participants, in addition to self-report survey measures of benefit, satisfaction, and implant usage., Results: Participants were placed into one of five hierarchic categories of speech perception performance preimplantation and at 12 mo postimplantation. The categories ranged from sound detection only (category 1) to excellent open-set speech perception (category 5). To be in category 4 or 5, the participant had to score.30% words correct on a recorded version of either the Central Institute for the Deaf Everyday Sentence Lists or the City University of New York Sentences. Before implantation, two recipients (5%) were in category 4 or 5 compared with 20 (53%) at 12 mo postimplant. Consistent with previous studies, there was large intersubject variability in speech scores. Three factors accounted for 63% of the variance on open-set sentence test scores, postimplant: mode of communication in childhood (oral versus total communication/sign), stable as opposed to progressive loss, and time without a hearing aid on the implant ear. More than 80% of survey respondents used their device.8 hr a day, and 90% reported that their ability to understand speech with visual cues was "much better" with the implant. In addition, all reported being satisfied with the device., Conclusion: These results indicate that a cochlear implant should be considered as an option for adults and adolescents with early-onset HL. The majority of participants gained benefit from the device and were satisfied with it. In addition, a substantial number gained good open-set speech perception ability, postimplant. Recipients who used oral communication in childhood, had a progressive loss, and wore a hearing aid on the implant ear up to the time of surgery were more likely to obtain better speech perception outcomes.
- Published
- 2012
- Full Text
- View/download PDF
32. Evaluation of NRT and behavioral measures for MAPping elderly cochlear implant users.
- Author
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Pedley K, Psarros C, Gardner-Berry K, Parker A, Purdy SC, Dawson P, and Plant K
- Subjects
- Action Potentials, Aged, Aged, 80 and over, Auditory Threshold, Deafness physiopathology, Electrophysiology, Female, Humans, Male, Noise, Patient Satisfaction, Time Factors, Behavior, Cochlear Implants, Deafness psychology, Deafness rehabilitation, Nervous System physiopathology, Speech Perception, Telemetry
- Abstract
We investigated the acceptability of electrophysiologically derived MAPs and the effect of these MAPs on speech perception in elderly adults using Nucleus 24 cochlear implants. Eight implant recipients aged 75 years or older trialed an electrophysiologically derived MAP and a behavioral MAP. The electrophysiologically derived MAP was based on the threshold and maximum comfort level for electrode 10 and evoked compound action potential thresholds measured on six electrodes using neural response telemetry (NRT). Word perception at 55 dB SPL and sentence perception in noise at 70 dB SPL were assessed after six weeks take-home experience and again after an additional two weeks of experience. During the final two weeks of take-home experience participants indicated their preferred MAP for different listening situations. The NRT derived MAP estimated behavioral T levels well, but underestimated behavioral C levels for apical electrodes in some subjects. Speech perception with NRT derived MAPs was comparable to speech perception with behaviorally measured MAPs. MAPs estimated from NRT data provided good speech perception outcomes for elderly implant recipients and were well tolerated.
- Published
- 2007
- Full Text
- View/download PDF
33. Evaluation of streamlined programming procedures for the Nucleus cochlear implant with the Contour electrode array.
- Author
-
Plant K, Law MA, Whitford L, Knight M, Tari S, Leigh J, Pedley K, and Nel E
- Subjects
- Adult, Aged, Aged, 80 and over, Audiometry, Speech, Female, Humans, Male, Middle Aged, Patient Satisfaction, Prosthesis Design, Prosthesis Fitting, Surveys and Questionnaires, Cochlear Implants, Hearing Loss therapy, Software standards, Speech Perception physiology
- Abstract
Objective: The objective of this study was to evaluate streamlined programming procedures for the Nucleus cochlear implant system with the Contour electrode array., Design: Phase 1 involved an examination of the clinical MAPs for the first 103 recipients implanted with the Contour electrode array in the Melbourne Cochlear Implant Clinic, to examine the ability to predict the entire MAP based on a smaller number of clinically determined T- and/or C-levels. In phase 2, a subset of the streamlined procedures was selected and clinically evaluated, using speech perception and subjective preference measures. In the first study, the clinical MAP was compared with a MAP based on interpolating across three behavioral T-levels and three behavioral C-levels in a group of newly implanted subjects. The second study investigated the use of a single interpolated profile as the basis to creating the entire MAP. Initial evaluation compared the clinical MAP with two streamlined MAPs, one in which the C-level profile was derived from interpolation across a subset of T-levels and one in which the T-level profile was derived from interpolation across a subset of C-levels. In this case, the interpolated profile was based on five behavioral measures. Subsequently, the use of either three or a single T-level measure as the basis for the interpolated T-level profile was evaluated. Eighteen subjects, who were experienced with the clinical MAP before enrollment in the study, participated in the initial evaluation. The subjects were selected to include a group whose RMS deviation from clinical MAP levels, as determined in Phase 1, was greater than that of the wider population., Results: The Phase 1 analysis showed that as expected, larger differences were observed between the clinical and derived MAP levels as interpolation was applied across fewer measured electrodes and that the use of a single interpolated profile to create the entire MAP resulted in the greatest deviation. No significant group mean difference was found in speech perception scores for newly implanted subjects when mapped with the clinical versus the streamlined MAP based on three behavioral T- and three behavioral C-level measures. For some individual subjects, scores were higher with the streamlined MAP. Subjective reports from the comparative performance questionnaire were consistent with these findings. No significant group mean difference in speech perception scores was found in comparing the clinical MAP with the streamlined MAPs based on a single interpolated T- or C-level profile created from five behavioral measures. Individual effects were observed; however, there was no consistent finding across subjects. The use of three rather than five behavioral T-level measures in the procedure did not result in significantly lower group mean scores; however, significantly poorer scores were obtained for three of the 10 individual subjects. The use of a MAP based on a single behavioral measure did result in poorer speech perception scores when compared with the MAP based on five behavioral T-level measures. These findings were consistent with subjective results from the performance questionnaires administered to determine preference for program across a range of listening situations., Conclusions: Two streamlined programming procedures are recommended for use in the clinical setting: (1) interpolating across three measured T-levels and three measured C-levels and (2) interpolating across five measured T- or C-levels and using the interpolated profile for fitting of the alternative profile.
- Published
- 2005
- Full Text
- View/download PDF
34. Evaluating the health-related quality of life effects of cochlear implants: a prospective study of an adult cochlear implant program.
- Author
-
Hawthorne G, Hogan A, Giles E, Stewart M, Kethel L, White K, Plaith B, Pedley K, Rushbrooke E, and Taylor A
- Subjects
- Deafness diagnosis, Female, Follow-Up Studies, Health Status, Humans, Male, Middle Aged, Models, Statistical, Program Evaluation, Prospective Studies, Self Efficacy, Severity of Illness Index, Surveys and Questionnaires, Cochlear Implantation, Deafness psychology, Deafness rehabilitation, Quality of Life
- Abstract
This paper prospectively documents the health-related quality of life (HRQoL) and social participation benefits of adult patients receiving cochlear implants in Australia and New Zealand. Thirty-four consecutively implanted patients completed the Assessment of Quality of Life (AQoL) and Hearing Participation Scale (HPS) instruments before implantation, and at 3- and 6-month follow-ups. Implantation resulted in significant improvements in AQoL and HPS scores, The effect size was 1.09 for both measures. Those in the top socio-economic tertile obtained the greatest gains. The HRQoL and social participation benefits were slightly larger than those reported elsewhere. This may be because participants used more recent technology (Nucleus 24 rather than Nucleus 22) and received auditory and self-efficacy training as part of their rehabilitation. The results suggest that cochlear implants have a large beneficial effect. They show that social and HRQoL outcomes can be parsimoniously measured using the HPS and AQoL instruments.
- Published
- 2004
- Full Text
- View/download PDF
35. Heterogeneity in nuclear transport does not affect the timing of DNA synthesis in quiescent mammalian nuclei induced to replicate in Xenopus egg extracts.
- Author
-
Sun WH, Hola M, Baldwin N, Pedley K, and Brooks RF
- Subjects
- Amino Acid Sequence, Animals, Microscopy, Fluorescence, Molecular Sequence Data, Nuclear Proteins metabolism, Nucleoplasmins, Phosphoproteins metabolism, Xenopus, Cell Nucleus metabolism, DNA Replication, Ovum ultrastructure
- Abstract
Intact G0 nuclei from quiescent mammalian cells initiate DNA synthesis asynchronously in Xenopus egg extracts, despite exposure to the same concentration of replication factors. This indicates that individual nuclei differ in their ability to respond to the inducers of DNA replication. Since the induction of DNA synthesis requires the accumulation of replication factors by active nuclear transport, any variation in the rate of transport among nuclei could contribute to the variability of DNA replication. Using the naturally fluorescent protein allophycocyanin (APC) coupled with the nuclear localization sequence (NLS) of SV40 T antigen, as a marker of nuclear uptake, we show here that individual G0 nuclei differ in their rate of transport over a range of more than 20-fold. Surprisingly, this variation has no direct influence on the timing or extent of DNA synthesis. Similar results were obtained by monitoring the uptake of nucleoplasmin, a nuclear protein present at high levels in egg extracts. These experiments show that the initiation of DNA synthesis is not driven merely by the accumulation of replication factors to some threshold concentration. Instead, some other explanation is needed to account for the timing of initiation.
- Published
- 2001
- Full Text
- View/download PDF
36. The replication capacity of intact mammalian nuclei in Xenopus egg extracts declines with quiescence, but the residual DNA synthesis is independent of Xenopus MCM proteins.
- Author
-
Sun W, Hola M, Pedley K, Tada S, Blow JJ, Todorov IT, Kearsey SE, and Brooks RF
- Subjects
- 3T3 Cells, Adenine analogs & derivatives, Adenine pharmacology, Animals, Blood Proteins pharmacology, Cell Nucleus chemistry, Chromatin metabolism, Cyclin-Dependent Kinases metabolism, DNA Replication drug effects, DNA-Binding Proteins metabolism, Enzyme Inhibitors pharmacology, Mammals, Mice, Minichromosome Maintenance 1 Protein, Minichromosome Maintenance Complex Component 2, Nuclear Envelope metabolism, Nuclear Proteins genetics, Nuclear Proteins metabolism, Oocytes physiology, Transcription Factors metabolism, Xenopus, Cell Nucleus metabolism, DNA Replication physiology, DNA-Binding Proteins genetics, Transcription Factors genetics
- Abstract
In eukaryotes, the initiation of DNA synthesis requires the assembly of a pre-replicative complex (pre-RC) at origins of replication. This involves the sequential binding of ORC (origin-recognition-complex), Cdc6 and MCM proteins, a process referred to as licensing. After origin firing, the Cdc6 and MCM proteins dissociate from the chromatin, and do not rebind until after the completion of mitosis, thereby restricting replication to a single round in each cell cycle. Although nuclei normally become licensed for replication as they enter G(1), the extent to which the license is retained when cells enter the quiescent state (G(0)) is controversial. Here we show that the replication capacity of nuclei from Swiss 3T3 cells, in Xenopus egg extracts, is not lost abruptly with the onset of quiescence, but instead declines gradually. The decline in replication capacity, which affects both the number of nuclei induced to replicate and their subsequent rate of DNA synthesis, is accompanied by a fall in the level of chromatin-bound MCM2. When quiescent nuclei are incubated in egg extracts, they do not bind further MCMs unless the nuclei are first permeabilized. The residual replication capacity of intact nuclei must therefore be dependent on the remaining endogenous MCMs. Although high levels of Cdk activity are known to block MCM binding, we show that the failure of intact nuclei in egg extracts to increase their bound MCMs is not due to their uptake and accumulation of Cdk complexes. Instead, the failure of binding must be due to exclusion of some other binding factor from the nucleus, or to the presence within nuclei of an inhibitor of binding other than Cdk activity. In contrast to the situation in Xenopus egg extracts, following serum stimulation of intact quiescent cells, the level of bound MCMs does increase before the cells reach S phase, without any disruption of the nuclear envelope.
- Published
- 2000
- Full Text
- View/download PDF
37. Membrane proteins at the interface of erythrocytes fused by treatment with polyethylene glycol.
- Author
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Litwa M, Maggs AM, Jin CZ, Wang WD, Pedley K, Beaven GH, and Gratzer WB
- Subjects
- Anion Exchange Protein 1, Erythrocyte drug effects, Ankyrins drug effects, Erythrocyte Membrane chemistry, Erythrocyte Membrane ultrastructure, Humans, Membrane Lipids blood, Microscopy, Confocal, Microscopy, Fluorescence, Models, Chemical, Spectrin drug effects, Cell Fusion drug effects, Erythrocyte Membrane drug effects, Membrane Proteins drug effects, Polyethylene Glycols pharmacology
- Abstract
Fusion of human red cells through the action of polyethylene glycol gives rise to pairs or higher clusters with a common membrane envelope, in which a barrier at the position of the original interface can be seen in phase contrast. At early times this septum contains lipids, as judged by labelling with a fluorescent lipophile, and transmembrane protein; this was shown by the presence of the preponderant component, band 3, detected by a fluorescent label, covalently attached before fusion at an extracellular site, or by immunofluorescence with anti-band 3 antibody. Ankyrin, which is bound to band 3, is also observed in the septum. The lipid thereafter disappears from the interface, carrying most of the band 3 with it. A continuous membrane skeletal network, defined by the presence of spectrin (detected by immunofluorescent staining in epifluorescence and confocal microscopy) appears to persist for long periods, but in many cells interruptions develop in the septum. In other fused pairs, particularly at longer times, the interface is seen to have vanished completely. Protease inhibitors have no discernible effect on any of these observations. The results suggest a model for the events that follow fusion. Covalent cross-linking of membrane proteins beyond a critical level causes inhibition of fusion, suggesting that proteins, probably the membrane skeletal network, regulate the fusion process. The efficiency of fusion is strikingly dependent on the composition of the isotonic medium, being relatively high at an orthophosphate concentration of 5 mM and minimal at 20 mM.
- Published
- 1997
- Full Text
- View/download PDF
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