James Gordon - Academia.edu (original) (raw)

Papers by James Gordon

Scientific reports, Jan 8, 2018

Human motor cortex can activate pelvic floor muscles (PFM), but the motor cortical representation... more Human motor cortex can activate pelvic floor muscles (PFM), but the motor cortical representation of the PFM is not well characterized. PFM representation is thought to be focused in the supplementary motor area (SMA). Here we examine the degree to which PFM representation is distributed between SMA and the primary motor cortex (M1), and how this representation is utilized to activate the PFM in different coordination patterns. We show that two types of coordination patterns involving PFM can be voluntarily accessed: one activates PFM independently of synergists and a second activates PFM prior to and in proportion with synergists (in this study, the gluteus maximus muscle - GMM). Functional magnetic resonance imaging (fMRI) showed that both coordination patterns involve overlapping activation in SMA and M1, suggesting the presence of intermingled but independent neural populations that access the different patterns. Transcranial magnetic stimulation (TMS) confirmed SMA and M1 repre...

Public reporting burden for this collection of information is estimated to average 1 hour per res... more Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1200 individuals attended the 2007 International Meeting on Simulation in Healthcare and had access to panels, keynotes and workshop sessions to further their knowledge of use of simulation in healthcare to improve patient safety and manage resources. 26 workshops provided both hands-on and interactive learning in the areas of conducting research, outcomes based assessment, case development, disaster training, needs assessment and competency based training. Panels and keynotes addressed education, research, simulations operations, interactive environments, credentialing & assessment, clinical areas, economics of simulation and standardized patients. 72 peer reviewed abstracts were presented and are published in the Society's Journal, Simulation in Healthcare. 15. SUBJECT TERMS Simulation, healthcare, credentialing, assessment 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON

Western New England Law Review, 2014

whole nature responds to the principle of equality of all men before the law, as well as to the p... more whole nature responds to the principle of equality of all men before the law, as well as to the principle of the equal protection by the laws for everyone in his personal and property rights."-John Marshall Harlan 1 [T]o be labeled a prophet is to be held to an impossible standard. In many ways, Harlan's views fell short of our current notions of racial equality. But Harlan was not a philosopher; he was a judge. His job was not to divine eternal truths, but to make socially situated legal judgments. It is correct to say that Harlan's views on race were as problematic in some ways as they were progressive in others. But in reaching that conclusion, we benefit from a century's worth of hindsight and experience that Harlan did not have.

for supporting this project with a summer research grant. The author also wishes to thank his col... more for supporting this project with a summer research grant. The author also wishes to thank his colleagues Anne B. Goldstein and Arthur D. Wolf for reading earlier drafts of this essay and offering helpful comments. 1. J. HURST, THE GROWTH OF AMERICAN LAW: THE LAWMAKERS 252 (1950).

Journal of hospital medicine, Jan 15, 2015

Residency training is charged with improving resident teaching skills. Utilizing simulation in te... more Residency training is charged with improving resident teaching skills. Utilizing simulation in teacher training has unique advantages such as providing a controlled learning environment and opportunities for deliberate practice. We assessed the impact of a simulation-based resident-as-teacher (RaT) program. A RaT program was embedded in an existing 8-case simulation curriculum for 52 internal medicine (IM) interns. Residents participated in a workshop, then served as facilitators in the curriculum and received feedback from faculty. Residents' teaching and feed back skills were measured using a pre- and post-program self-assessment and post-session and post-curriculum evaluations by intern learners. Forty-one second- and third-year residents participated in the study August 2013 to October 2013 at a single center. Pre- and post-program teaching skills were assessed for 34 of 41 resident facilitators (83%) participating in 3.9 sessions on average. Partaking in the program led to ...

Technology in cancer research & treatment, Jan 10, 2015

To evaluate the overall positioning accuracy of image-guided intracranial radiosurgery across mul... more To evaluate the overall positioning accuracy of image-guided intracranial radiosurgery across multiple linear accelerator platforms. A computed tomography scan with a slice thickness of 1.0 mm was acquired of an anthropomorphic head phantom in a BrainLAB U-frame mask. The phantom was embedded with three 5-mm diameter tungsten ball bearings, simulating a central, a left, and an anterior cranial lesion. The ball bearings were positioned to radiation isocenter under ExacTrac X-ray or cone-beam computed tomography image guidance on 3 Linacs: (1) ExacTrac X-ray localization on a Novalis Tx; (2) cone-beam computed tomography localization on the Novalis Tx; (3) cone-beam computed tomography localization on a TrueBeam; and (4) cone-beam computed tomography localization on an Edge. Each ball bearing was positioned 5 times to the radiation isocenter with different initial setup error following the 4 image guidance procedures on the 3 Linacs, and the mean (µ) and one standard deviation (σ) of ...

Medical Physics, 2014

To investigate the potential advantages of multiple anatomy optimization (MAO) for lung cancer ra... more To investigate the potential advantages of multiple anatomy optimization (MAO) for lung cancer radiation therapy compared to the internal target volume (ITV) approach. Methods: MAO aims to optimize a single fluence to be delivered under free-breathing conditions such that the accumulated dose meets the plan objectives, where accumulated dose is defined as the sum of deformably mapped doses computed on each phase of a single four dimensional computed tomography (4DCT) dataset. Phantom and patient simulation studies were carried out to investigate potential advantages of MAO compared to ITV planning. Through simulated delivery of the ITV-and MAO-plans, target dose variations were also investigated. Results: By optimizing the accumulated dose, MAO shows the potential to ensure dose to the moving target meets plan objectives while simultaneously reducing dose to organs at risk (OARs) compared with ITV planning. While consistently superior to the ITV approach, MAO resulted in equivalent OAR dosimetry at planning objective dose levels to within 2% volume in 14/30 plans and to within 3% volume in 19/30 plans for each lung V20, esophagus V25, and heart V30. Despite large variations in per-fraction respiratory phase weights in simulated deliveries at high dose rates (e.g., treating 4/10 phases during single fraction beams) the cumulative clinical target volume (CTV) dose after 30 fractions and per-fraction dose were constant independent of planning technique. In one case considered, however, per-phase CTV dose varied from 74% to 117% of prescription implying the level of ITV-dose heterogeneity may not be appropriate with conventional, free-breathing delivery. Conclusions: MAO incorporates 4DCT information in an optimized dose distribution and can achieve a superior plan in terms of accumulated dose to the moving target and OAR sparing compared to ITV-plans. An appropriate level of dose heterogeneity in MAO plans must be further investigated.

The Journal of Neuroscience, 2015

The interaction between brightness and color causes there to be different color appearance when o... more The interaction between brightness and color causes there to be different color appearance when one and the same object is viewed against surroundings of different brightness. Brightness contrast causes color to be desaturated, as has been found in perceptual experiments on color induction and color-gamut expansion in human vision. However, it is not clear yet where in the cerebral cortex the brightness–color interaction that causes these major perceptual effects is located. One hypothesis is that brightness and color signals are processed separately and in parallel within the primary visual cortex V1 and only interact in extrastriate cortex. Another hypothesis is that color and brightness contrast interact strongly already within V1. We localized the brightness–color interaction in human V1 by means of recording the chromatic visual-evoked potential. The chromatic visual-evoked potential measurements decisively support the idea that brightness–color interaction arises in a recurren...

Simulation in healthcare : journal of the Society for Simulation in Healthcare, 2006

To critically analyze the experience of clinical clerkship students exposed to simulator-based te... more To critically analyze the experience of clinical clerkship students exposed to simulator-based teaching, in order to better understand student perspectives on its utility. A convenience sample of clinical students (n = 95) rotating through an emergency medicine, surgery, or longitudinal patient-doctor clerkship voluntarily participated in a 2-hour simulator-based teaching session. Groups of 3-5 students managed acute scenarios including respiratory failure, myocardial infarction, or multisystem trauma. After the session, students completed a brief written evaluation asking for free text commentary on the strengths and weaknesses of the experience; they also provided simple satisfaction ratings. Using a qualitative research approach, the textual commentary was transcribed and parsed into fragments, coded for emergent themes, and tested for inter-rater agreement. Six major thematic categories emerged from the qualitative analysis: The "Knowledge & Curriculum" domain was desc...

Spatial Vision, 2006

A gray region can be made to look colored by a colored surround. This phenomenon, chromatic induc... more A gray region can be made to look colored by a colored surround. This phenomenon, chromatic induction, depends on color differences around the boundary of the region. We performed experiments on chromatic induction with small, initially achromatic, targets on nine different colored surrounds ranging in color from blue to red. Using scaling of saturation as our measure of perceived color strength, we found that chromatic induction is at its maximum when the brightness contrast at the boundary between target and surroundings is minimal. This implies that the neural mechanism in the cerebral cortex that mediates the appearance of brightness at a boundary inhibits the activity of chromatic mechanisms at that same boundary. Observers matched the apparent brightness and luminance of each of the colored surrounds. For surround colors where brightness and luminance matches differ, brightness contrast, not luminance contrast, controls chromatic induction. These new findings, taken together with other evidence, require a new theory of color appearance that includes mutually inhibitory interactions between color and brightness mechanisms that are sensing color and brightness contrast at visual boundaries.

Physical Therapy, 2011

Assessed for Eligibility (n=127) Randomized (n=80) Excluded Did not meet inclusion criteria (n=47... more Assessed for Eligibility (n=127) Randomized (n=80) Excluded Did not meet inclusion criteria (n=47) Attention control group (n=40) Received allocated intervention (n=36) Did not receive intervention (n=4) Reasons: Unexplained weight loss (n=1) Lost to follow-up (n=3) Exercise/movement optimization group (n=40) Received allocated intervention (n=35) Did not receive intervention (n=5) Reasons: Pressure ulcer (n=1) Lost to follow-up (n=4) Lost to Follow-up at Week 12 (n=6) Reasons: None given Lost to Follow-up at Week 12 (n=3) Reasons: None given Discontinued Intervention (n=1) Reasons: Deep vein thrombosis Discontinued Intervention (n=3) Reasons: Neck pain, fall, spider bite

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1994

An integrated imaging sensor system is being developed to enhance operations of robots and telero... more An integrated imaging sensor system is being developed to enhance operations of robots and telerobotic systems used in nuclear industry. This system combines a gamma ray image of the distribution of radioactivity with a video image of the area, allowing a rapid and intuitive determination of the source location. The gamma ray imaging system is based upon a position sensitive photomultiplier tube, a segmented scintillator, and a pinhole collimator which provides high quality images in the energy range of 0.1 to 1.5 MeV. The design and measured performance of a prototype of this system will be discussed.

Medical Physics, 2012

Purpose:This work uses repeat images of intensity modulated radiation therapy (IMRT) fields to qu... more Purpose:This work uses repeat images of intensity modulated radiation therapy (IMRT) fields to quantify fluence anomalies (i.e., delivery errors) that can be reliably detected in electronic portal images used for IMRT pretreatment quality assurance.Methods:Repeat images of 11 clinical IMRT fields are acquired on a Varian Trilogy linear accelerator at energies of 6 MV and 18 MV. Acquired images are corrected for output variations and registered to minimize the impact of linear accelerator and electronic portal imaging device (EPID) positioning deviations. Detection studies are performed in which rectangular anomalies of various sizes are inserted into the images. The performance of detection strategies based on pixel intensity deviations (PIDs) and gamma indices is evaluated using receiver operating characteristic analysis.Results:Residual differences between registered images are due to interfraction positional deviations of jaws and multileaf collimator leaves, plus imager noise. P...

Medical Physics, 2011

A dosimetric margin ͑DM͒ is the margin in a specified direction between a structure and a specifi... more A dosimetric margin ͑DM͒ is the margin in a specified direction between a structure and a specified isodose surface, corresponding to a prescription or tolerance dose. The dosimetric margin distribution ͑DMD͒ is the distribution of DMs over all directions. Given a geometric uncertainty model, representing inter-or intrafraction setup uncertainties or internal organ motion, the DMD can be used to calculate coverage Q, which is the probability that a realized target or organ-at-risk ͑OAR͒ dose metric D v exceeds the corresponding prescription or tolerance dose. Postplanning coverage evaluation quantifies the percentage of uncertainties for which target and OAR structures meet their intended dose constraints. The goal of the present work is to evaluate coverage probabilities for 28 prostate treatment plans to determine DMD sampling parameters that ensure adequate accuracy for postplanning coverage estimates. Methods: Normally distributed interfraction setup uncertainties were applied to 28 plans for localized prostate cancer, with prescribed dose of 79.2 Gy and 10 mm clinical target volume to planning target volume ͑CTV-to-PTV͒ margins. Using angular or isotropic sampling techniques, dosimetric margins were determined for the CTV, bladder and rectum, assuming shift invariance of the dose distribution. For angular sampling, DMDs were sampled at fixed angular intervals ͑e.g., =1°,2°,5°,10°,20°͒. Isotropic samples were uniformly distributed on the unit sphere resulting in variable angular increments, but were calculated for the same number of sampling directions as angular DMDs, and accordingly characterized by the effective angular increment eff. In each direction, the DM was calculated by moving the structure in radial steps of size ␦͑=0.1, 0.2, 0.5, 1 mm͒ until the specified isodose was crossed. Coverage estimation accuracy ⌬Q was quantified as a function of the sampling parameters or eff and ␦. Results: The accuracy of coverage estimates depends on angular and radial DMD sampling parameters or eff and ␦, as well as the employed sampling technique. Target ͉⌬Q͉ Ͻ 1% and OAR ͉⌬Q͉ Ͻ 3% can be achieved with sampling parameters or eff = 20°, ␦ = 1 mm. Better accuracy ͑target ͉⌬Q͉ Ͻ 0.5% and OAR ͉⌬Q͉ Ͻ ϳ 1%͒ can be achieved with or eff = 10°, ␦ = 0.5 mm. As the number of sampling points decreases, the isotropic sampling method maintains better accuracy than fixed angular sampling. Conclusions: Coverage estimates for post-planning evaluation are essential since coverage values of targets and OARs often differ from the values implied by the static margin-based plans. Finer sampling of the DMD enables more accurate assessment of the effect of geometric uncertainties on coverage estimates prior to treatment. DMD sampling with or eff = 10°and ␦ = 0.5 mm should be adequate for planning purposes.

Journal of Public Economics, 1988

and U.B.C. and an anonymous referee for helpful and constructive comments. Errors remain our own.... more and U.B.C. and an anonymous referee for helpful and constructive comments. Errors remain our own. 'See, for example, Sandmo (1981), Cowell (1985), and Slemrod and Yitzhaki (1987). 2Exceptions are the original Kolm paper, Gottheb (1985) and Hansson (1985). The effect of how the government spends taxes on the labour supply decision has however been considered. See Lindbeck (1982).

The Journal of neuroscience : the official journal of the Society for Neuroscience, 2004

Cathode ray tubes (CRTs) display images refreshed at high frequency, and the temporal waveform of... more Cathode ray tubes (CRTs) display images refreshed at high frequency, and the temporal waveform of each pixel is a luminance impulse only a few milliseconds long. Although humans are perceptually oblivious to this flicker, we show in V1 in macaque monkeys and in humans that extracellularly recorded action potentials (spikes) and visual-evoked potentials (VEPs) align with the video impulses, particularly when high-contrast stimuli are viewed. Of 91 single units analyzed in macaque with a 60 Hz video refresh, 29 cells (32%) significantly locked their firing to a uniform luminance display, but their number increased to 75 (82%) when high-contrast stimuli were shown. Of 92 cells exposed to a 100 Hz refresh, 21 (23%) significantly phase locked to high-contrast stimuli. Phase locking occurred in both input and output layers of V1 for simple and complex cells, regardless of preferred temporal frequency. VEPs recorded in humans showed significant phase locking to the video refresh in all sev...

Journal of Applied Research in Intellectual Disabilities, 2013

Background-In individuals with Down syndrome virtually all structures of the eye have some abnorm... more Background-In individuals with Down syndrome virtually all structures of the eye have some abnormality which likely diminishes vision. We examined basic vision functions in adults with Down syndrome. Materials and Methods-Participants completed a battery of psychophysical tests which probed a comprehensive array of visual functions. The performance of adults with Down syndrome was compared to younger and older adults without intellectual disability. Results-Adults with Down syndrome had significant vision deficits; reduced sensitivity across spatial frequencies and temporal modulation rates, reduced stereopsis, impaired vernier acuity, and anomalies in colour discrimination. The pattern of deficits observed was similar to those seen by researchers examining adults with Alzheimer's disease. Conclusions-Our findings suggest that a common mechanism may be responsible for the pattern of deficits observed, possibly the presence of Alzheimer's disease neuropathology in the visual association cortex. We also showed that individuals with mild to moderate intellectual disability are capable of participating in studies employing state-of-the-art psychophysical procedures. This has wider implications in terms of their ability to participate in research that use similar techniques.

International Journal of Stress Management, 2011

CITATION Staples, JK, Abdel Atti, JA, & Gordon, JS (2011, June 27). Mind-Body Skills Groups f... more CITATION Staples, JK, Abdel Atti, JA, & Gordon, JS (2011, June 27). Mind-Body Skills Groups for Posttraumatic Stress Disorder and Depression Symptoms in Palestinian Children and Adolescents in Gaza. International Journal of Stress Management. Advance online publication. doi: ...

International Journal of Radiation Oncology*Biology*Physics, 2011

regulation of the mitochondrial acetylome is critical to regulate how cells respond to oxidative ... more regulation of the mitochondrial acetylome is critical to regulate how cells respond to oxidative stressed. In addition, Sirt3 is the primary mitochondrial protein deacetylase. Thus, we hypothesized that Sirt3 may respond to the stress of therapeutic irradiation to prevent IR-induced damage. A direct extension of this hypothesis would be that cells and/or normal tissues lacking Sirt3 would be permissive to IR-induced damage. Materials/Methods: Sirt3+/+ and Sirt3-/-mice were exposed to 4 Gy of radiation and livers harvested at 24 hours. Results: Histological examination of the irradiated Sirt3-/-livers demonstrated marked periportal hepatocellular swelling, dilation of the cytoplasm, and poorly defined vacuoles pathologically consistent with liver damage referred to as liver steatosis. When these mouse livers were stained with markers for apoptosis, the Sirt3-/-mice exposed to IR demonstrated significantly more apoptosis, as compared to the Sirt3+/+ samples, as measured by TUNEL assay or staining for cleaved caspase-3. Sirt3-/-mouse liver cells also exhibited increased anti-nitrotyrosine staining that is a marker for increased protein damage by intracellular (ONOO-) a reaction product of nitric oxide and superoxide. Conclusions: These results, for the first time, suggest that the genetics of aging are connected to how normal tissue responds to the damaging effects of IR and definitively demonstrate that the mitochondria are a critical target for IR-induced cell death.

Experimental Brain Research, 1994

This study examined the variability in movement end points in a task in which human subjects reac... more This study examined the variability in movement end points in a task in which human subjects reached to targets in different locations on a horizontal surface. The primary purpose was to determine whether patterns in the variable errors would reveal the nature and origin of the coordinate system in which the movements were planned. Six subjects moved a hand-held cursor on a digitizing tablet. Target and cursor positions were displayed on a computer screen, and vision of the hand and arm was blocked. The screen cursor was blanked during movement to prevent visual corrections. The paths of the movements were straight and thus directions were largely specified at the onset of movement. The velocity profiles were bell-shaped, and peak velocities and accelerations were scaled to target distance, implying that movement extent was also programmed in advance of the movement. The spatial distributions of movement end points were elliptical in shape. The major axes of these ellipses were systematically oriented in the direction of hand movement with respect to its initial position. This was true for both fast and slow movements, as well as for pointing movements involving rotations of the wrist joint. Using principal components analysis to compute the axes of these ellipses, we found that the eccentricity of the elliptical dispersions was uniformly greater for small than for large movements: variability along the axis of movement, representing extent variability, increased markedly but nonlinearly with distance. Variability perpendicular to the direction of movement, which results from directional errors, was generally smaller than extent variability, but it increased in proportion to the extent of the movement. Therefore,