32 results on '"Fraser LE"'
Search Results
2. A knee arthroscopy simulator: Design and validation.
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Abelardo Escoto, Fraser Le Ber, Ana Luisa Trejos, Michael D. Naish, Rajni V. Patel, and Marie-Eve LeBel
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- 2013
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3. Absence of effects of widespread badger culling on tuberculosis in cattle
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Paul R. Torgerson, Sonja Hartnack, Philip Rasmussen, Fraser Lewis, and Thomas E. S. Langton
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Medicine ,Science - Abstract
Abstract Government policy in England aims for the elimination of bovine tuberculosis (bTB). This policy includes culling of European badger (Meles meles) to reduce cattle TB incidence. The rationale is based on a field trial, the Randomised Badger Culling Trial (RBCT) 1998–2005, which reported a substantial decrease in bTB herd incidence where badger culling had been implemented, in comparison to untreated control areas. The RBCT was undertaken because previous studies of reductions in badgers by culling, reported a possible association between bTB in badger and cattle, but none could directly show causation. The effect of intensive widespread (proactive) culling in the RBCT was reported in 2006 in the journal Nature. Analysis of an extensive badger removal programme in England since 2013 has raised concerns that culling has not reduced bTB herd incidence. The present study re-examined RBCT data using a range of statistical models. Most analytical options showed no evidence to support an effect of badger culling on bTB herd incidence ‘confirmed’ by visible lesions and/or bacterial culture post mortem following a comparative intradermal skin test (SICCT). However, the statistical model chosen by the RBCT study was one of the few models that showed an effect. Various criteria suggest that this was not an optimal model, compared to other analytical options available. The most likely explanation is that the RBCT proactive cull analysis over-fitted the data with a non-standard method to control for exposure giving it a poor predictive value. Fresh appraisal shows that there was insufficient evidence to conclude RBCT proactive badger culling affected bTB breakdown incidence. The RBCT found no evidence of an effect of culling on ‘total’ herd incidence rates. Total herd incidences include those confirmed as bTB at necropsy and those herds where there was at least one animal animal positive to the comparative intradermal skin test, the standard diagnostic test used for routine surveillance, but not confirmed at necropsy. This was also the case using the more suitable statistical models. Use only of ‘confirmed’ herd incidence data, together with a more recent (2013) published perception that RBCT data presented ‘a strong evidence base….with appropriate detailed statistical or other quantitative analysis’ should be reconsidered. The results of the present report are consistent with other analyses that were unable to detect any disease control benefits from badger culling in England (2013–2019). This study demonstrates one form of potential driver to the reproducibility crisis, in this case with disease control management in an increasingly intensified livestock industry.
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- 2024
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4. Determining the Nature of IC 10 X-2: A Comprehensive Study of the Optical/IR Emission from an Extragalactic BeHMXB
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Jwaher Alnaqbi, Joseph D. Gelfand, Payaswini Saikia, Craig Heinke, M. C. Baglio, David M. Russell, Guobao Zhang, Antonios Manousakis, Ivan Yu. Katkov, and Fraser Lewis
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High mass x-ray binary stars ,Astrophysics ,QB460-466 - Abstract
We present a comprehensive analysis of the optical and infrared (IR) properties of high-mass X-ray binary (HMXB) IC 10 X-2, classified as a supergiant HMXB and superfast X-ray transient by previous work. Our analysis of regular (daily and weekly) observations by both the Zwicky Transient Facility and Las Cumbres Observatory over a 5 yr period indicates both periodic flares and variations in the apparent magnitude and color with a period of ∼26.5 days—likely the orbital period of this binary system. The periodic flaring suggests the stellar companion is a Be star, with flares resulting from increased accretion onto the neutron star (NS) when it enters the stellar decretion disk. The periodic variations in the optical/IR brightness and color likely result from orbital variations in the hydrogen column density along the line of sight or a transient accretion disk around the NS. Lastly, the numerous short-duration episodes where IC 10 X-2 is significantly “redder” or “bluer” than normal likely result from clumps within this system—which can accrete onto the NS (causing IC 10 X-2 to appear bluer) or pass through the line of sight (causing IC 10 X-2 to appear redder). These results substantially increase our understanding of the evolution of this source, which is a significant source of ionizing photons in its host galaxy IC 10, a low-mass, metal-poor starburst galaxy similar in many respects to those thought to be common in the early Universe.
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- 2025
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5. Chasing the Break: Tracing the Full Evolution of a Black Hole X-Ray Binary Jet with Multiwavelength Spectral Modeling
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Constanza Echiburú-Trujillo, Alexandra J. Tetarenko, Daryl Haggard, Thomas D. Russell, Karri I. I. Koljonen, Arash Bahramian, Jingyi Wang, Michael Bremer, Joe Bright, Piergiorgio Casella, David M. Russell, Diego Altamirano, M. Cristina Baglio, Tomaso Belloni, Chiara Ceccobello, Stephane Corbel, Maria Diaz Trigo, Dipankar Maitra, Aldrin Gabuya, Elena Gallo, Sebastian Heinz, Jeroen Homan, Erin Kara, Elmar Körding, Fraser Lewis, Matteo Lucchini, Sera Markoff, Simone Migliari, James C. A. Miller-Jones, Jerome Rodriguez, Payaswini Saikia, Craig L. Sarazin, Tariq Shahbaz, Gregory Sivakoff, Roberto Soria, Vincenzo Testa, Bailey E. Tetarenko, and Valeriu Tudose
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X-ray binary stars ,Low-mass x-ray binary stars ,Radio jets ,Astrophysics ,QB460-466 - Abstract
Black hole (BH) X-ray binaries (XRBs) are ideal targets to study the connection between accretion inflow and jet outflow. Here we present quasi-simultaneous, multiwavelength observations of the Galactic BH system MAXI J1820+070, throughout its 2018–2019 outburst. Our data set includes coverage from the radio through X-ray bands from 17 different instruments/telescopes, and encompasses 19 epochs over a 7 month period, resulting in one of the most well-sampled multiwavelength data sets of a BH XRB outburst to date. With our data, we compile and model the broadband spectra of this source using a phenomenological model that includes emission from the jet, a companion star, and an accretion flow. This modeling allows us to track the evolution of the spectral break in the jet spectrum, a key observable that samples the jet launching region. We find that the spectral break location changes over at least ≈3 orders of magnitude in electromagnetic frequency over this period. Using these spectral break measurements, we link the full cycle of jet behavior, including the rising, quenching, and reignition, to the changing accretion flow properties as the source evolves through its different accretion states. Our analysis shows consistent jet behavior with other sources in similar phases of their outbursts, reinforcing the idea that jet quenching and recovery may be a global feature of BH XRB systems in outburst. Our results also provide valuable evidence supporting a close connection between the geometry of the inner accretion flow and the base of the jet.
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- 2024
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6. A Multiwavelength Study of the Hard and Soft States of MAXI J1820+070 During Its 2018 Outburst
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Srimanta Banerjee, Gulab C. Dewangan, Christian Knigge, Maria Georganti, Poshak Gandhi, N. P. S. Mithun, Payaswini Saikia, Dipankar Bhattacharya, David M. Russell, Fraser Lewis, and Andrzej A. Zdziarski
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Accretion ,Black hole physics ,Astronomy data analysis ,Low-mass x-ray binary stars ,X-ray astronomy ,Astrophysics ,QB460-466 - Abstract
We present a comprehensive multiwavelength spectral analysis of the black hole (BH) X-ray binary MAXI J1820+070 during its 2018 outburst, utilizing AstroSat far-UV, soft X-ray, and hard X-ray data, along with (quasi-)simultaneous optical and X-ray data from the Las Cumbres Observatory and NICER, respectively. In the soft state, we detect soft X-ray and UV/optical excess components over and above the intrinsic accretion disk emission ( kT _in ∼ 0.58 keV) and a steep X-ray power-law component. The soft X-ray excess is consistent with a high-temperature blackbody ( kT ∼ 0.79 keV), while the UV/optical excess is described by UV emission lines and two low-temperature blackbody components ( kT ∼ 3.87 and ∼0.75 eV). Employing continuum spectral fitting, we determine the BH spin parameter ( a = 0.77 ± 0.21), using the jet inclination angle of 64° ± 5° and a mass spanning 5–10 M _☉ . In the hard state (HS), we observe a significantly enhanced optical/UV excess component, indicating a stronger reprocessed emission in the outer disk. Broadband X-ray spectroscopy in the HS reveals a two-component corona, each associated with its reflection component, in addition to the disk emission ( kT _in ∼ 0.19 keV). The softer coronal component dominates the bolometric X-ray luminosity and produces broader relativistic reflection features, while the harder component gets reflected far from the inner disk, yielding narrow reflection features. Furthermore, our analysis in the HS suggests a substantial truncation of the inner disk (≳51 gravitational radii) and a high disk density (∼10 ^20 cm ^−3 ).
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- 2024
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7. Gaia22dkvLb: A Microlensing Planet Potentially Accessible to Radial-velocity Characterization
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Zexuan Wu, Subo Dong, Tuan Yi, Zhuokai Liu, Kareem El-Badry, Andrew Gould, L. Wyrzykowski, K. A. Rybicki, Etienne Bachelet, Grant W. Christie, L. de Almeida, L. A. G. Monard, J. McCormick, Tim Natusch, P. Zieliński, Huiling Chen, Yang Huang, Chang Liu, A. Mérand, Przemek Mróz, Jinyi Shangguan, Andrzej Udalski, J. Woillez, Huawei Zhang, Franz-Josef Hambsch, P. J. Mikołajczyk, M. Gromadzki, M. Ratajczak, Katarzyna Kruszyńska, N. Ihanec, Uliana Pylypenko, M. Sitek, K. Howil, Staszek Zola, Olga Michniewicz, Michal Zejmo, Fraser Lewis, Mateusz Bronikowski, Stephen Potter, Jan Andrzejewski, Jaroslav Merc, Rachel Street, Akihiko Fukui, R. Figuera Jaimes, V. Bozza, P. Rota, A. Cassan, M. Dominik, Y. Tsapras, M. Hundertmark, J. Wambsganss, K. Bąkowska, and A. Słowikowska
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Gravitational microlensing exoplanet detection ,Astronomy ,QB1-991 - Abstract
We report discovering an exoplanet from following up a microlensing event alerted by Gaia. The event Gaia22dkv is toward a disk source rather than the traditional bulge microlensing fields. Our primary analysis yields a Jovian planet with ${M}_{{\rm{p}}}={0.59}_{-0.05}^{+0.15}\,{M}_{{\rm{J}}}$ at a projected orbital separation ${r}_{\perp }={1.4}_{-0.3}^{+0.8}$ au, and the host is a ∼1.1 M _⊙ turnoff star at ∼1.3 kpc. At $r^{\prime} \approx 14$ , the host is far brighter than any previously discovered microlensing planet host, opening up the opportunity to test the microlensing model with radial velocity (RV) observations. RV data can be used to measure the planet’s orbital period and eccentricity, and they also enable searching for inner planets of the microlensing cold Jupiter, as expected from the “inner–outer correlation” inferred from Kepler and RV discoveries. Furthermore, we show that Gaia astrometric microlensing will not only allow precise measurements of its angular Einstein radius θ _E but also directly measure the microlens parallax vector and unambiguously break a geometric light-curve degeneracy, leading to the definitive characterization of the lens system.
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- 2024
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8. Additive Bayesian Network Modeling with the R Package abn
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Gilles Kratzer, Fraser Lewis, Arianna Comin, Marta Pittavino, and Reinhard Furrer
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structure learning ,graphical models ,greedy and exact search ,scoring algorithm ,GLM ,graph theory ,Statistics ,HA1-4737 - Abstract
The R package abn is designed to fit additive Bayesian network models to observational datasets and contains routines to score Bayesian networks based on Bayesian or information theoretic formulations of generalized linear models. It is equipped with exact search and greedy search algorithms to select the best network, and supports continuous, discrete and count data in the same model and input of prior knowledge at a structural level. The Bayesian implementation supports random effects to control for one-layer clustering. In this paper, we give an overview of the methodology and illustrate the package's functionality using a veterinary dataset concerned with respiratory diseases in commercial swine production.
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- 2023
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9. A combined microphysiological-computational omics approach in dietary protein evaluation
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Paulus G. M. Jochems, Willem R. Keusters, Antoine H. P. America, Pascale C. S. Rietveld, Shanna Bastiaan-Net, Renata M. C. Ariëns, Monic M. M. Tomassen, Fraser Lewis, Yang Li, Koen G. C. Westphal, Johan Garssen, Harry J. Wichers, Jeroen van Bergenhenegouwen, and Rosalinde Masereeuw
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Nutrition. Foods and food supply ,TX341-641 ,Food processing and manufacture ,TP368-456 - Abstract
Abstract Food security is under increased pressure due to the ever-growing world population. To tackle this, alternative protein sources need to be evaluated for nutritional value, which requires information on digesta peptide composition in comparison to established protein sources and coupling to biological parameters. Here, a combined experimental and computational approach is presented, which compared seventeen protein sources with cow’s whey protein concentrate (WPC) as the benchmark. In vitro digestion of proteins was followed by proteomics analysis and statistical model-based clustering. Information on digesta peptide composition resulted in 3 cluster groups, primarily driven by the peptide overlap with the benchmark protein WPC. Functional protein data was then incorporated in the computational model after evaluating the effects of eighteen protein digests on intestinal barrier integrity, viability, brush border enzyme activity, and immune parameters using a bioengineered intestine as microphysiological gut system. This resulted in 6 cluster groups. Biological clustering was driven by viability, brush border enzyme activity, and significant differences in immune parameters. Finally, a combination of proteomic and biological efficacy data resulted in 5 clusters groups, driven by a combination of digesta peptide composition and biological effects. The key finding of our holistic approach is that protein source (animal, plant or alternative derived) is not a driving force behind the delivery of bioactive peptides and their biological efficacy.
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- 2020
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10. Seven Reflares, a Mini Outburst, and an Outburst: High-amplitude Optical Variations in the Black Hole X-Ray Binary Swift J1910.2–0546
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Payaswini Saikia, David M. Russell, Saarah F. Pirbhoy, M. C. Baglio, D. M. Bramich, Kevin Alabarta, Fraser Lewis, and Phil Charles
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Stellar mass black holes ,Low-mass x-ray binary stars ,Accretion ,Jets ,Optical astronomy ,Astrophysics ,QB460-466 - Abstract
We present long-term (2012–2022) optical monitoring of the candidate black hole X-ray binary Swift J1910.2–0546 with the Faulkes Telescopes and Las Cumbres Observatory network. Following its initial bright 2012 outburst, we find that the source displayed a series of at least seven quasi-periodic, high-amplitude (~3 mag) optical reflares in 2013, with a recurrence time increasing from ∼42 to ∼49 days. In 2014, the source experienced a mini outburst with two peaks in the optical. We also study the recent 2022 outburst of the source at optical wavelengths, and perform a comparative analysis with the earlier rebrightenings. A single X-ray detection and only two radio detections were obtained during the 2013 reflaring period, and only optical detections were acquired in 2014. During the reflaring in both 2013 and 2014, the source showed bluer-when-brighter behavior, having optical colors consistent with blackbody heating and cooling between 4500 and 9500 K, i.e., the temperature range in which hydrogen starts to ionize. Finally, we compare the flaring behavior of the source to rebrightening events in other X-ray binaries. We show that the repeated reflarings of Swift J1910.2–0546 are highly unusual, and propose that they arise from a sequence of repetitive heating and cooling front reflections traveling through the accretion disk.
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- 2023
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11. Clinical Outcomes of Symptomatic Neuroma Resection and Reconstruction with Processed Nerve Allograft
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Sonu A. Jain, MD, FACS, Jason Nydick, DO, Fraser Leversedge, MD, Dominic Power, MD, Joseph Styron, MD, PhD, Bauback Safa, MD, and Gregory Buncke, MD
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Surgery ,RD1-811 - Abstract
Background:. Neuromas causing sensory disturbance can substantially affect nerve function and quality of life. Historically, passive termination of the nerve end and proximal relocation to muscle or bone has been performed after neuroma resection, but this method does not allow for neurologic recovery or prevent recurrent neuromas. The use of processed nerve allografts (PNAs) for intercalary reconstruction of nerve defects following neuroma resection is reasonable for neuroma management, although reported outcomes are limited. The purpose of this study was to assess the outcomes of pain reduction and functional recovery following neuroma resection and intercalary nerve reconstruction using PNA. Methods:. Data on outcomes of PNA use for peripheral nerve reconstruction were collected from a multicenter registry study. The registry database was queried for upper extremity nerve reconstruction with PNA after resection of symptomatic neuroma. Patients completing both pain and quantitative sensory assessments were included in the analysis. Improvement in pain-related symptoms was determined via patient self-reported outcomes and/or the visual analog scale. Meaningful sensory recovery was defined as a score of at least S3 on the Medical Research Council Classification scale. Results:. Twenty-five repairs involving 21 patients were included in this study. The median interval from injury to reconstruction was 386 days, and the average nerve defect length was 31 mm. Pain improved in 80% of repairs. Meaningful sensory recovery was achieved in 88% of repairs. Conclusion:. Neuroma resection and nerve reconstruction using PNA can reduce or eliminate chronic peripheral nerve pain and provide meaningful sensory recovery.
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- 2021
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12. Associations between preconception macronutrient intake and birth weight across strata of maternal BMI.
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Nastaran Salavati, Marian K Bakker, Fraser Lewis, Petra C Vinke, Farya Mubarik, JanJaap H M Erwich, and Eline M van der Beek
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Medicine ,Science - Abstract
IntroductionMaternal nutrition during pregnancy is linked with birth outcomes including fetal growth, birth weight, congenital anomalies and long-term health through intra-uterine programming. However, a woman's nutritional status before pregnancy is a strong determinant in early embryo-placental development, and subsequently outcomes for both mother and child. Therefore, the aim of this study was to investigate the association between dietary macronutrient intake in the preconception period with birth weight.MethodsWe studied a group of 1698 women from the Dutch Perined-Lifelines linked birth cohort with reliable detailed information on preconception dietary macronutrient intake (using a semi quantitative food frequency questionnaire) and data available on birth weight of the offspring. Birth weight was converted into gestational age adjusted z-scores, and macronutrient intake was adjusted for total energy intake using the nutrient residual method. Preconception BMI was converted into cohort-based quintiles. Multivariable linear regression was performed, adjusted for other macronutrients and covariates.ResultsMean maternal age was 29.5 years (SD 3.9), preconception BMI: 24.7 kg/m2 (SD 4.2) and median daily energy intake was 1812 kcal (IQR 1544-2140). Mean birth weight was 3578 grams (SD 472). When adjusted for covariates, a significant association (adjusted z score [95% CI], P) between polysaccharides and birth weight was shown (0.08 [0.01-0.15], 0.03). When linear regression analyses were performed within cohort-based quintiles of maternal BMI, positive significant associations between total protein, animal protein, fat, total carbohydrates, mono-disaccharides and polysaccharides with birth weight were shown in the lowest quintile of BMI independent of energy intake, intake of other macronutrients and covariates.ConclusionOut of all macronutrients studied, polysaccharides showed the strongest association with birth weight, independent of energy intake and other covariates. Our study might suggest that specifically in women with low preconception BMI a larger amount of macronutrient intake was associated with increased birth weight. We recommend that any dietary assessment and advise during preconception should be customized to preconception weight status of the women.
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- 2020
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13. Metabolic activity of boar semen stored in different extenders supplemented with ostrich egg yolk lipoproteins
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Dziekońska Anna, Kinder Marek, Fraser Leyland, Strzeżek Jerzy, and Kordan Władysław
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boar ,sperm ,extender ,lipoprotein ,metabolism ,Veterinary medicine ,SF600-1100 - Abstract
Introduction: The aim of this study was to evaluate the effect of lipoprotein fraction isolated from ostrich egg yolk (LPFo) on the metabolic activity of boar spermatozoa following liquid semen storage in different extenders and temperatures.
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- 2017
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14. Robotic Astronomy with the Faulkes Telescopes and Las Cumbres Observatory Global Telescope
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Fraser Lewis, Rachel Street, Paul Roche, Vanessa Stroud, and David M. Russell
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Astronomy ,QB1-991 - Abstract
We present results from ongoing science projects conducted by members of the Faulkes Telescope (FT) team and Las Cumbres Observatory Global Telescope (LCOGT). Many of these projects incorporate observations carried out and analysed by FT users, comprising amateur astronomers and schools. We also discuss plans for the further development of the LCOGT network.
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- 2010
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15. Episodic sexual transmission of HIV revealed by molecular phylodynamics.
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Fraser Lewis, Gareth J Hughes, Andrew Rambaut, Anton Pozniak, and Andrew J Leigh Brown
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Medicine - Abstract
BackgroundThe structure of sexual contact networks plays a key role in the epidemiology of sexually transmitted infections, and their reconstruction from interview data has provided valuable insights into the spread of infection. For HIV, the long period of infectivity has made the interpretation of contact networks more difficult, and major discrepancies have been observed between the contact network and the transmission network revealed by viral phylogenetics. The high rate of HIV evolution in principle allows for detailed reconstruction of links between virus from different individuals, but often sampling has been too sparse to describe the structure of the transmission network. The aim of this study was to analyze a high-density sample of an HIV-infected population using recently developed techniques in phylogenetics to infer the short-term dynamics of the epidemic among men who have sex with men (MSM).Methods and findingsSequences of the protease and reverse transcriptase coding regions from 2,126 patients, predominantly MSM, from London were compared: 402 of these showed a close match to at least one other subtype B sequence. Nine large clusters were identified on the basis of genetic distance; all were confirmed by Bayesian Monte Carlo Markov chain (MCMC) phylogenetic analysis. Overall, 25% of individuals with a close match with one sequence are linked to 10 or more others. Dated phylogenies of the clusters using a relaxed clock indicated that 65% of the transmissions within clusters took place between 1995 and 2000, and 25% occurred within 6 mo after infection. The likelihood that not all members of the clusters have been identified renders the latter observation conservative.ConclusionsReconstruction of the HIV transmission network using a dated phylogeny approach has revealed the HIV epidemic among MSM in London to have been episodic, with evidence of multiple clusters of transmissions dating to the late 1990s, a period when HIV prevalence is known to have doubled in this population. The quantitative description of the transmission dynamics among MSM will be important for parameterization of epidemiological models and in designing intervention strategies.
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- 2008
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16. White versus gray matter: fMRI hemodynamic responses show similar characteristics, but differ in peak amplitude
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Fraser Leanne M, Stevens M, Beyea Steven D, and D’Arcy Ryan C N
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White matter ,Functional connectivity ,BOLD response ,Hemodynamic response function ,Event-related fMRI ,Interhemispheric transfer ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 ,Neurophysiology and neuropsychology ,QP351-495 - Abstract
Abstract Background There is growing evidence for the idea of fMRI activation in white matter. In the current study, we compared hemodynamic response functions (HRF) in white matter and gray matter using 4 T fMRI. White matter fMRI activation was elicited in the isthmus of the corpus callosum at both the group and individual levels (using an established interhemispheric transfer task). Callosal HRFs were compared to HRFs from cingulate and parietal activation. Results Examination of the raw HRF revealed similar overall response characteristics. Finite impulse response modeling confirmed that the WM HRF characteristics were comparable to those of the GM HRF, but had significantly decreased peak response amplitudes. Conclusions Overall, the results matched a priori expectations of smaller HRF responses in white matter due to the relative drop in cerebral blood flow (CBF) and cerebral blood volume (CBV). Importantly, the findings demonstrate that despite lower CBF and CBV, white matter fMRI activation remained within detectable ranges at 4 T.
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- 2012
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17. A gene-rich linkage map in the dioecious species Actinidia chinensis (kiwifruit) reveals putative X/Y sex-determining chromosomes
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Gill Geoffrey P, Harvey Catherine F, De Silva H Nihal, Datson Paul M, Tsang Gianna K, Fraser Lena G, Crowhurst Ross N, and McNeilage Mark A
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Biotechnology ,TP248.13-248.65 ,Genetics ,QH426-470 - Abstract
Abstract Background The genus Actinidia (kiwifruit) consists of woody, scrambling vines, native to China, and only recently propagated as a commercial crop. All species described are dioecious, but the genetic mechanism for sex-determination is unknown, as is the genetic basis for many of the cluster of characteristics making up the unique fruit. It is, however, an important crop in the New Zealand economy, and a classical breeding program would benefit greatly by knowledge of the trait alleles carried by both female and male parents. The application of marker assisted selection (MAS) in seedling populations would also aid the accurate and efficient development of novel fruit types for the market. Results Gene-rich female, male and consensus linkage maps of the diploid species A. chinensis have been constructed with 644 microsatellite markers. The maps consist of twenty-nine linkage groups corresponding to the haploid number n = 29. We found that sex-linked sequence characterized amplified region (SCAR) markers and the 'Flower-sex' phenotype consistently mapped to a single linkage group, in a subtelomeric region, in a section of inconsistent marker order. The region also contained markers of expressed genes, some of unknown function. Recombination, assessed by allelic distribution and marker order stability, was, in the remainder of the linkage group, in accordance with other linkage groups. Fully informative markers to other genes in this linkage group identified the comparative linkage group in the female map, where recombination ratios determining marker order were similar to the autosomes. Conclusion We have created genetic linkage maps that define the 29 linkage groups of the haploid genome, and have revealed the position and extent of the sex-determining locus in A. chinensis. As all Actinidia species are dioecious, we suggest that the sex-determining loci of other Actinidia species will be similar to that region defined in our maps. As the extent of the non-recombining region is limited, our result supports the suggestion that the subtelomeric region of an autosome is in the early stages of developing the characteristics of a sex chromosome. The maps provide a reference of genetic information in Actinidia for use in genetic analysis and breeding programs.
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- 2009
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18. Analysis of expressed sequence tags from Actinidia: applications of a cross species EST database for gene discovery in the areas of flavor, health, color and ripening
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Richardson Annette C, Rassam Maysoon, McNeilage Mark A, Nain Bhawana, MacDiarmid Robin M, Lo Kim R, Klages Karin, Janssen Bart J, Hellens Roger P, Gera Emma, Fraser Lena G, Ferguson A Ross, Eckloff Rheinhart, Davy Marcus W, Bowen Judith H, Boldingh Helen L, Allan Andrew C, Usadel Björn, Schaffer Robert J, Newcomb Richard D, Montefiori Mirco, Matich Adam J, Marsh Ken B, Chagne David, Bulley Sean M, Beuning Lesley L, Atkinson Ross G, Ampomah-Dwamena Charles, MacRae Elspeth A, Gleave Andrew P, Crowhurst Ross N, Rikkerink Erik HA, Ross Gavin S, Schröder Roswitha, Snowden Kimberley C, Souleyre Edwige JF, Templeton Matt D, Walton Eric F, Wang Daisy, Wang Mindy Y, Wang Yanming Y, Wood Marion, Wu Rongmei, Yauk Yar-Khing, and Laing William A
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Biotechnology ,TP248.13-248.65 ,Genetics ,QH426-470 - Abstract
Abstract Background Kiwifruit (Actinidia spp.) are a relatively new, but economically important crop grown in many different parts of the world. Commercial success is driven by the development of new cultivars with novel consumer traits including flavor, appearance, healthful components and convenience. To increase our understanding of the genetic diversity and gene-based control of these key traits in Actinidia, we have produced a collection of 132,577 expressed sequence tags (ESTs). Results The ESTs were derived mainly from four Actinidia species (A. chinensis, A. deliciosa, A. arguta and A. eriantha) and fell into 41,858 non redundant clusters (18,070 tentative consensus sequences and 23,788 EST singletons). Analysis of flavor and fragrance-related gene families (acyltransferases and carboxylesterases) and pathways (terpenoid biosynthesis) is presented in comparison with a chemical analysis of the compounds present in Actinidia including esters, acids, alcohols and terpenes. ESTs are identified for most genes in color pathways controlling chlorophyll degradation and carotenoid biosynthesis. In the health area, data are presented on the ESTs involved in ascorbic acid and quinic acid biosynthesis showing not only that genes for many of the steps in these pathways are represented in the database, but that genes encoding some critical steps are absent. In the convenience area, genes related to different stages of fruit softening are identified. Conclusion This large EST resource will allow researchers to undertake the tremendous challenge of understanding the molecular basis of genetic diversity in the Actinidia genus as well as provide an EST resource for comparative fruit genomics. The various bioinformatics analyses we have undertaken demonstrates the extent of coverage of ESTs for genes encoding different biochemical pathways in Actinidia.
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- 2008
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19. Linking Signal Relevancy and Intensity in Predictive Tactile Suppression.
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Beyvers MC, Fraser LE, and Fiehler K
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Predictable somatosensory feedback leads to a reduction in tactile sensitivity. This phenomenon, called tactile suppression , relies on a mechanism that uses an efference copy of motor commands to help select relevant aspects of incoming sensory signals. We investigated whether tactile suppression is modulated by (a) the task-relevancy of the predicted consequences of movement and (b) the intensity of related somatosensory feedback signals. Participants reached to a target region in the air in front of a screen; visual or tactile feedback indicated the reach was successful. Furthermore, tactile feedback intensity (strong vs. weak) varied across two groups of participants. We measured tactile suppression by comparing detection thresholds for a probing vibration applied to the finger either early or late during reach and at rest. As expected, we found an overall decrease in late-reach suppression, as no touch was involved at the end of the reach. We observed an increase in the degree of tactile suppression when strong tactile feedback was given at the end of the reach, compared to when weak tactile feedback or visual feedback was given. Our results suggest that the extent of tactile suppression can be adapted to different demands of somatosensory processing. Downregulation of this mechanism is invoked only when the consequences of missing a weak movement sequence are severe for the task. The decisive factor for the presence of tactile suppression seems not to be the predicted action effect as such, but the need to detect and process anticipated feedback signals occurring during movement., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Beyvers, Fraser and Fiehler.)
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- 2022
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20. Virtual Hand Illusion in younger and older adults.
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Campos JL, El-Khechen Richandi G, Coahran M, Fraser LE, Taati B, and Keshavarz B
- Abstract
Introduction: Embodiment involves experiencing ownership over our body and localizing it in space and is informed by multiple senses (visual, proprioceptive and tactile). Evidence suggests that embodiment and multisensory integration may change with older age. The Virtual Hand Illusion (VHI) has been used to investigate multisensory contributions to embodiment, but has never been evaluated in older adults. Spatio-temporal factors unique to virtual environments may differentially affect the embodied perceptions of older and younger adults., Methods: Twenty-one younger (18-35 years) and 19 older (65+ years) adults completed the VHI paradigm. Body localization was measured at baseline and again, with subjective ownership ratings, following synchronous and asynchronous visual-tactile interactions., Results: Higher ownership ratings were observed in the synchronous relative to the asynchronous condition, but no effects on localization/drift were found. No age differences were observed. Localization accuracy was biased in both age groups when the virtual hand was aligned with the real hand, indicating a visual mislocalization of the virtual hand., Conclusions: No age-related differences in the VHI were observed. Mislocalization of the hand in VR occurred for both groups, even when congruent and aligned; however, tactile feedback reduced localization biases. Our results expand the current understanding of age-related changes in multisensory embodiment within virtual environments., Competing Interests: Declaration of conflicting interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2021.)
- Published
- 2021
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21. Predicted reach consequences drive time course of tactile suppression.
- Author
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Fraser LE and Fiehler K
- Subjects
- Adult, Biomechanical Phenomena, Feedback, Physiological, Female, Fingers physiology, Humans, Male, Models, Biological, Touch Perception physiology, Young Adult, Motor Activity physiology, Touch physiology
- Abstract
Sensitivity to touch is reduced during movement; this tactile suppression is likely the result of a mechanism that suppresses self-generated movement consequences. We sought to determine whether tactile suppression is modulated by naturally evoked changes in movement speed driven by task precision demands (Exp.1), and by changes in predicted movement consequences (Exp.2). We measured suppression by comparing detection thresholds for a vibration applied to the finger during reach and at rest. In Experiment 1 we varied reach target size to create a speed-accuracy tradeoff, where participants decelerated more to smaller targets to accurately hit them. We theorized that the reduction in late-reach speed associated with higher precision demands might lead to a reduction in late-reach suppression, consistent with the literature showing a positive relationship between speed and suppression. Contrary to our hypothesis, we found suppression increased towards the end of the reach in all conditions, despite a significant decrease in reaching speed. We postulated this might be a de-emphasizing of the predicted tactile feedback associated with tapping the target. To test this, in Experiment 2 we paired a vibration consequence with a target of a certain colour. We found an increase in late-reach suppression for this target compared to a target of another colour with no associated consequence. Our results indicate that tactile suppression is temporally sensitive and increases as predicted consequences become more likely. We propose the positive correlation between movement speed and suppression previously reported may be driven by the predicted somatosensory consequences associated with increased movement speed., (Copyright © 2018 Elsevier B.V. All rights reserved.)
- Published
- 2018
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22. The Weighting of Cues to Upright Following Stroke With and Without a History of Pushing.
- Author
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Fraser LE, Mansfield A, Harris LR, Merino DM, Knorr S, and Campos JL
- Subjects
- Aged, Aged, 80 and over, Case-Control Studies, Female, Functional Laterality, Humans, Male, Middle Aged, Photic Stimulation, Stroke physiopathology, Stroke psychology, Virtual Reality, Cues, Orientation, Perceptual Disorders etiology, Proprioception physiology, Visual Perception physiology
- Abstract
Objective: Perceived upright depends on three main factors: vision, graviception, and the internal representation of the long axis of the body. We assessed the relative contributions of these factors in individuals with sub-acute and chronic stroke and controls using a novel tool; the Oriented Character Recognition Test (OCHART). We also considered whether individuals who displayed active pushing or had a history of pushing behaviours had different weightings than those with no signs of pushing., Method: Three participants experienced a stroke 6 months prior: eight with a history of pushing. In total, 12 participants served as healthy aged-matched controls. Visual and graviceptive cues were dissociated by orienting the visual background left, right, or upright relative to the body, or by orienting the body left, right, or upright relative to gravity. A three-vector model was used to quantify the weightings of vision, graviception, and the body to the perceptual upright., Results: The control group showed weightings of 13% vision, 25% graviception, and 62% body. Some individuals with stroke showed a similar pattern; others, particularly those with recent stroke, showed different patterns, for example, being unaffected by one of the three factors. The participant with active pushing behaviour displayed an ipsilesional perceptual bias (>30°) and was not affected by visual cues to upright., Conclusion: The results of OCHART may be used to quantify the weightings of multisensory inputs in individuals post-stroke and may help characterize perceptual sources of pushing behaviours.
- Published
- 2018
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23. The effect of hand position on perceived finger orientation in left- and right-handers.
- Author
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Fraser LE and Harris LR
- Subjects
- Adolescent, Adult, Female, Humans, Male, Movement physiology, Posture, Psychomotor Performance physiology, Young Adult, Fingers physiology, Functional Laterality physiology, Hand, Orientation physiology, Orientation, Spatial physiology, Proprioception physiology
- Abstract
In the absence of visual feedback, the perceived orientation of the fingers is systematically biased. In right-handers these biases are asymmetrical between the left and right hands in the horizontal plane and may reflect common functional postures for the two hands. Here we compared finger orientation perception in right- and left-handed participants for both hands, across various hand positions in the horizontal plane. Participants rotated a white line on a screen optically superimposed over their hand to indicate the perceived position of the finger that was rotated to one of seven orientations with the hand either aligned with the body midline, aligned with the shoulder, or displaced by twice the shoulder-to-midline distance from the midline. We replicated the asymmetric pattern of biases previously reported in right-handed participants (left hand biased towards an orientation ~30° inward, right hand ~10° inward). However, no such asymmetry was found for left-handers, suggesting left-handers may use different strategies when mapping proprioception to body or space coordinates and/or have less specialization of function between the hands. Both groups' responses rotated further outward as distance of the hand from the body midline increased, consistent with other research showing spatial orientation estimates diverge outward in the periphery. Finally, for right-handers, precision of responses was best when the hand was aligned with the shoulder compared to the other two conditions. These results highlight the unique role of hand dominance and hand position in perception of finger orientation, and provide insight into the proprioceptive position sense of the upper limbs.
- Published
- 2017
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24. Perceived finger orientation is biased towards functional task spaces.
- Author
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Fraser LE and Harris LR
- Subjects
- Adult, Analysis of Variance, Female, Functional Laterality, Gravitation, Humans, Male, Middle Aged, Young Adult, Bias, Fingers physiology, Orientation physiology, Perception physiology
- Abstract
In the absence of visual feedback, the perceived position of the hands is systematically biased towards the plausible manual task space. Here we tested whether perceived orientation of the finger is similarly misperceived in right-handed individuals. Participants' index fingers were passively rotated about the middle joint to a range of test angles, either in the frontoparallel plane (Experiment 1) or the horizontal plane (Experiment 2); they reported perceived orientation of the finger by rotating a visual line presented on a screen optically superimposed on the location of their unseen finger. Perceived finger orientations were biased towards positions that varied across hands and planes. Both hands were biased towards 10° inward in the frontoparallel plane and, in the horizontal plane, the left hand was biased towards 25° inward, whereas the right hand was biased towards 2° inwards. In a third experiment, participants reported finger orientation with respect to non-visual targets: gravitational vertical or straight ahead. Biases in perceived finger orientation to non-visual targets were similar to those found in the visual line task. The asymmetrical nature of biases across hands and planes reflects the typical orientation of the hands while working and supports the theory of a functional rather than anatomical representation of the fingers and hands in space.
- Published
- 2016
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25. The Subjective Visual Vertical and the Subjective Haptic Vertical Access Different Gravity Estimates.
- Author
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Fraser LE, Makooie B, and Harris LR
- Subjects
- Adolescent, Adult, Female, Gravitation, Head physiology, Head Movements physiology, Humans, Male, Neck Muscles, Otolithic Membrane physiology, Rotation, Young Adult, Orientation physiology, Posture physiology, Proprioception physiology, Visual Perception physiology
- Abstract
The subjective visual vertical (SVV) and the subjective haptic vertical (SHV) both claim to probe the underlying perception of gravity. However, when the body is roll tilted these two measures evoke different patterns of errors with SVV generally becoming biased towards the body (A-effect, named for its discoverer, Hermann Rudolph Aubert) and SHV remaining accurate or becoming biased away from the body (E-effect, short for Entgegengesetzt-effect, meaning "opposite", i.e., opposite to the A-effect). We compared the two methods in a series of five experiments and provide evidence that the two measures access two different but related estimates of gravitational vertical. Experiment 1 compared SVV and SHV across three levels of whole-body tilt and found that SVV showed an A-effect at larger tilts while SHV was accurate. Experiment 2 found that tilting either the head or the trunk independently produced an A-effect in SVV while SHV remained accurate when the head was tilted on an upright body but showed an A-effect when the body was tilted below an upright head. Experiment 3 repeated these head/body configurations in the presence of vestibular noise induced by using disruptive galvanic vestibular stimulation (dGVS). dGVS abolished both SVV and SHV A-effects while evoking a massive E-effect in the SHV head tilt condition. Experiments 4 and 5 show that SVV and SHV do not combine in an optimally statistical fashion, but when vibration is applied to the dorsal neck muscles, integration becomes optimal. Overall our results suggest that SVV and SHV access distinct underlying gravity percepts based primarily on head and body position information respectively, consistent with a model proposed by Clemens and colleagues.
- Published
- 2015
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26. How our body influences our perception of the world.
- Author
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Harris LR, Carnevale MJ, D'Amour S, Fraser LE, Harrar V, Hoover AE, Mander C, and Pritchett LM
- Abstract
Incorporating the fact that the senses are embodied is necessary for an organism to interpret sensory information. Before a unified perception of the world can be formed, sensory signals must be processed with reference to body representation. The various attributes of the body such as shape, proportion, posture, and movement can be both derived from the various sensory systems and can affect perception of the world (including the body itself). In this review we examine the relationships between sensory and motor information, body representations, and perceptions of the world and the body. We provide several examples of how the body affects perception (including but not limited to body perception). First we show that body orientation effects visual distance perception and object orientation. Also, visual-auditory crossmodal-correspondences depend on the orientation of the body: audio "high" frequencies correspond to a visual "up" defined by both gravity and body coordinates. Next, we show that perceived locations of touch is affected by the orientation of the head and eyes on the body, suggesting a visual component to coding body locations. Additionally, the reference-frame used for coding touch locations seems to depend on whether gaze is static or moved relative to the body during the tactile task. The perceived attributes of the body such as body size, affect tactile perception even at the level of detection thresholds and two-point discrimination. Next, long-range tactile masking provides clues to the posture of the body in a canonical body schema. Finally, ownership of seen body parts depends on the orientation and perspective of the body part in view. Together, all of these findings demonstrate how sensory and motor information, body representations, and perceptions (of the body and the world) are interdependent.
- Published
- 2015
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27. Patient care plans for intershift report.
- Author
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Fraser LE, O'Brien K, Tobar I, and Waller DM
- Subjects
- Child, Humans, Interprofessional Relations, Nursing Evaluation Research, Surveys and Questionnaires, Communication, Nursing Staff, Hospital psychology, Patient Care Planning standards, Pediatric Nursing methods
- Abstract
Inconsistent communication during intershift report had resulted in loss of vital information. This project was developed to implement the use of nursing care plans for intershift report on a 25-bed school-age unit. A review of literature showed an absence of any systematic method for intershift report. Classes that included a 20-minute video, written guidelines, and discussion were used to promote the use of nursing care plans for intershift report. A questionnaire was administered to the nursing staff 3 weeks after class to evaluate the project. The evaluation of use of the care plans indicated: (a) a more focused intershift report; (b) an improved structure for report, including important information about the child and family; (c) increased communication; (d) more practical up-to-date care plans; and (e) increased professionalism and collaboration.
- Published
- 1991
28. Haemophilus influenzae abscess presenting as an asymptomatic lung mass.
- Author
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Balter MS and Fraser LE
- Subjects
- Adult, Ampicillin therapeutic use, Diagnosis, Differential, Haemophilus Infections drug therapy, Haemophilus Infections pathology, Haemophilus influenzae, Humans, Lung Abscess drug therapy, Lung Abscess microbiology, Lung Abscess pathology, Male, Radiography, Haemophilus Infections diagnostic imaging, Lung Abscess diagnostic imaging, Lung Neoplasms diagnostic imaging
- Abstract
We report the radiographic and computed tomographic findings in an asymptomatic patient who had a Haemophilus influenzae lung abscess. The diagnosis was made by Gram's staining and culture of abscess material obtained by transthoracic needle aspiration. The radiographic abnormalities cleared after specific antimicrobial therapy.
- Published
- 1990
29. Experiences with hypophysectomy in mice. Criteria of complete removal.
- Author
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YOUNG S and FRASER LE
- Subjects
- Animals, Mice, Hypophysectomy
- Published
- 1960
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30. Para-aminobenzoic acid in treatment of Rocky Mountain spotted fever.
- Author
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FRASER LE, ROSENBLUM H, and DANCIGER JA
- Subjects
- 4-Aminobenzoic Acid, Acids therapy, Efficiency, Rocky Mountain Spotted Fever therapy
- Published
- 1948
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31. Detection and attempted assay of mammotrophic activity in women's blood and urine.
- Author
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FRASER LE, SPICER CC, WILLIAMS PC, and YOUNG S
- Subjects
- Female, Humans, Blood chemistry, Blood Chemical Analysis, Body Fluids, Breast, Progesterone pharmacology, Prolactin pharmacology, Protein Binding, Urine chemistry
- Published
- 1961
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32. Effect of para-aminobenzoic acid on fever and joint pains of acute rheumatic fever.
- Author
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ROSENBLUM H and FRASER LE
- Subjects
- 4-Aminobenzoic Acid, Acids, Arthralgia, Fever, Rheumatic Fever therapy
- Published
- 1947
- Full Text
- View/download PDF
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