29 results
A Pilot Randomized Controlled Trial of Augmented Reality Just-in-Time Guidance for the Performance of Rugged Field Procedures
- Laurel O’Connor, Sepahrad Zamani, Xinyi Ding, Nicolette McGeorge, Susan Latiff, Cindy Liu, Jorge Acevedo Herman, Matthew LoConte, Andrew Milsten, Michael Weiner, Timothy Boardman, Martin Reznek, Michael Hall, John P. Broach
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- Journal:
- Prehospital and Disaster Medicine , First View
- Published online by Cambridge University Press:
- 07 May 2024, pp. 1-9
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Introduction:
Medical resuscitations in rugged prehospital settings require emergency personnel to perform high-risk procedures in low-resource conditions. Just-in-Time Guidance (JITG) utilizing augmented reality (AR) guidance may be a solution. There is little literature on the utility of AR-mediated JITG tools for facilitating the performance of emergent field care.
Study Objective:The objective of this study was to investigate the feasibility and efficacy of a novel AR-mediated JITG tool for emergency field procedures.
Methods:Emergency medical technician-basic (EMT-B) and paramedic cohorts were randomized to either video training (control) or JITG-AR guidance (intervention) groups for performing bag-valve-mask (BVM) ventilation, intraosseous (IO) line placement, and needle-decompression (Needle-d) in a medium-fidelity simulation environment. For the interventional condition, subjects used an AR technology platform to perform the tasks. The primary outcome was participant task performance; the secondary outcomes were participant-reported acceptability. Participant task score, task time, and acceptability ratings were reported descriptively and compared between the control and intervention groups using chi-square analysis for binary variables and unpaired t-testing for continuous variables.
Results:Sixty participants were enrolled (mean age 34.8 years; 72% male). In the EMT-B cohort, there was no difference in average task performance score between the control and JITG groups for the BVM and IO tasks; however, the control group had higher performance scores for the Needle-d task (mean score difference 22%; P = .01). In the paramedic cohort, there was no difference in performance scores between the control and JITG group for the BVM and Needle-d tasks, but the control group had higher task scores for the IO task (mean score difference 23%; P = .01). For all task and participant types, the control group performed tasks more quickly than in the JITG group. There was no difference in participant usability or usefulness ratings between the JITG or control conditions for any of the tasks, although paramedics reported they were less likely to use the JITG equipment again (mean difference 1.96 rating points; P = .02).
Conclusions:This study demonstrated preliminary evidence that AR-mediated guidance for emergency medical procedures is feasible and acceptable. These observations, coupled with AR’s promise for real-time interaction and on-going technological advancements, suggest the potential for this modality in training and practice that justifies future investigation.
Transient subglacial water routing efficiency modulates ice velocities prior to surge termination on Sít’ Kusá, Alaska
- Yoram Terleth, Timothy C. Bartholomaus, Jukes Liu, Flavien Beaud, Thomas Dylan Mikesell, Ellyn Mary Enderlin
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- Journal:
- Journal of Glaciology , First View
- Published online by Cambridge University Press:
- 18 April 2024, pp. 1-17
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Glacier surges are opportunities to study large amplitude changes in ice velocities and accompanying links to subglacial hydrology. Although the surge phase is generally explained as a disruption in the glacier's ability to drain water from the bed, the extent and duration of this disruption remain difficult to observe. Here we present a combination of in situ and remotely sensed observations of subglacial water discharge and evacuation during the latter half of an active surge and subsequent quiescent period. Our data reveal intermittently efficient subglacial drainage prior to surge termination, showing that glacier surges can persist in the presence of channel-like subglacial drainage and that successive changes in subglacial drainage efficiency can modulate active phase ice dynamics at timescales shorter than the surge cycle. Our observations favor an explanation of fast ice flow sustained through an out-of-equilibrium drainage system and a basal water surplus rather than binary switching between states in drainage efficiency.
Foreword
- Timothy Hildebrandt, Jieyu Liu, Tim Pringle
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- Journal:
- The China Quarterly / Volume 257 / March 2024
- Published online by Cambridge University Press:
- 03 April 2024, pp. 1-2
- Print publication:
- March 2024
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Chapter 17 - Spondylolisthesis
- from Section 2 - Clinical Neurosurgical Diseases
- Edited by Farhana Akter, Harvard University, Massachusetts, Nigel Emptage, University of Oxford, Florian Engert, Harvard University, Massachusetts, Mitchel S. Berger, University of California, San Francisco
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- Neuroscience for Neurosurgeons
- Published online:
- 04 January 2024
- Print publication:
- 25 January 2024, pp 248-253
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Summary
Spondylolisthesis is defined as the slippage of one vertebra over another. When the posterior bony elements are dissociated from the anterior column, high shear forces on the disc can lead to slippage of the vertebral bodies on one another. There are five types: dysplastic isthmic, degenerative, traumatic, and pathological. Biomechanical models are limited and attempt to replicate on isthmic and degenerative etiologies. From a clinical standpoint, several studies have explored the relative efficacy of surgical versus non-operative treatment and among surgical treatments, the need for decompression and fusion vs decompression alone. While several landmark studies have established several guides to surgical treatment, the lack of consensus on the use of different surgical approaches leaves room for future work.
Propagating speedups during quiescence escalate to the 2020–2021 surge of Sít’ Kusá, southeast Alaska
- Jukes Liu, Ellyn M. Enderlin, Timothy C. Bartholomaus, Yoram Terleth, Thomas Dylan Mikesell, Flavien Beaud
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- Journal:
- Journal of Glaciology , First View
- Published online by Cambridge University Press:
- 09 January 2024, pp. 1-12
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We use satellite image processing techniques to measure surface elevation and velocity changes on a temperate surging glacier, Sít’ Kusá, throughout its entire 2013–2021 surge cycle. We present detailed records of its dynamic changes during quiescence (2013–2019) and its surge progression (2020–2021). Throughout quiescence, we observe order-of-magnitude speedups that propagate down-glacier seasonally from the glacier's upper northern tributary, above a steep icefall, into the reservoir zone for the surging portion of the glacier. The speedups initiate in fall and gradually accelerate through winter until they peak in late spring, ~1 − 2 months after the onset of melt. Propagation distance of the speedups controls the distribution of mass accumulation in the reservoir zone prior to the surge. Furthermore, the intensity and propagation distance of each year's speedup is correlated with the positive degree day sum from the preceding melt season, suggesting that winter melt storage drives the seasonal speedups. We demonstrate that the speedups are kinematically similar to the 2020–2021 surge, differing mainly in that the surge propagates past the dynamic balance line at the lower limit of the reservoir zone, likely triggered by the exceedance of a tipping point in mass accumulation and basal enthalpy in the reservoir zone.
3 Area Deprivation Index Interacts with Sex to Predict Atrophy and Cognitive Trajectory Over a 5-Year Follow-Up Period
- Marissa A Gogniat, Brina Ratangee, Omair A Khan, Francis Cambronero, Soumya Vytla, Michelle Houston, Dandan Liu, Timothy J Hohman, Katherine A Gifford, Angela L Jefferson
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 870-872
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Objective:
Area Deprivation Index (ADI) is a measurement of neighborhood disadvantage. Evidence suggests that living in a disadvantaged neighborhood has a negative impact on health outcomes independent of socioeconomic status, including increased risk for Alzheimer's disease (AD). However, less is known about the biological mechanisms that drive these associations. We examined how ADI influences structural imaging variables and cognitive performance in community-dwelling older adults. We hypothesized that greater neighborhood disadvantage would predict atrophy and worse cognitive trajectory over time.
Participants and Methods:Participants included the legacy cohort from the Vanderbilt Memory and Aging Project (n=295, 73±7 years of age, 16±3 years of education, 42% female, 85% non-Hispanic White) who lived in the state of Tennessee. T1-weighted and T2-weighted fluid-attenuated inversion recovery brain MRIs and a comprehensive neuropsychological assessment were acquired at baseline, 18-month, 3-year, 5-year and 7-year follow-up time (mean follow-up time=5.2 years). Annual change scores were calculated for all neuropsychological and structural MRI outcome variables. Baseline state ADI was calculated using the University of Wisconsin School of Medicine and Public Health Neighborhood Atlas (Kind & Buckingham, 2018) and was based on deciles where 1 represents the least deprived area and 10 represents the most. Mixed effects regression models related baseline ADI to longitudinal brain structure (volume, thickness, white matter hyperintensities) and neuropsychological trajectory (one test per model). Analyses adjusted for age, sex, race/ethnicity, education, Framingham Stroke Risk Profile score, (apolipoprotein) APOE-e4 status, cognitive status, and intracranial volume (for MRI outcomes). Models were repeated testing interactions with APOE-e4 status, sex, and cognitive status. A false discovery rate (FDR) correction for multiple comparisons was performed.
Results:On average, the sample was from relatively less disadvantaged neighborhoods in Tennessee (ADI state decile=2.4±1.8). Greater neighborhood disadvantage at study entry predicted more thinning of an AD-signature composite over time (ß=-0.002, p=0.005, pFDR=0.06); however, all other models testing MRI and neuropsychological outcomes were null (p-values>0.05, pFDR-values>0.51). Baseline ADI interacted with sex on longitudinal cortical thinning captured on the AD-signature composite (ß=0.004, p=0.006, pFDR=0.08) as well as several longitudinal cognitive outcomes including an executive function composite score (ß=0.033, p<0.001, pFDR=0.01), naming (ß=0.10, p=0.01, pFDR=0.12), visuospatial functioning (ß=0.083, p=0.02, pFDR=0.09), and an episodic memory composite score (ß=0.021, p=0.02, pFDR=0.07). In stratified models by sex, greater ADI predicted greater cortical thinning over time and worse longitudinal neuropsychological performance among men only. All stratified models in women were null except for executive function composite score, which did not survive correction for multiple comparisons (ß=-0.013, p=0.03, pFDR=0.61). Interactions by APOE-e4 and cognitive status were null (p-values>0.06, pFDR-values>0.61).
Conclusions:Among community-dwelling older adults, greater neighborhood disadvantage predicted greater cortical thinning over the mean 5-year follow-up in anatomical regions susceptible to AD-related neurodegeneration. Neighborhood disadvantage also interacted with sex on cortical thickness and several cognitive domains, with stronger effects found among men versus women. By contrast, there were no interactions between neighborhood disadvantage and genetic risk for AD or cognitive status. This study provides valuable evidence for sociobiological mechanisms that may underlie health disparities in aging adults whereby neighborhood deprivation is linked with neurodegeneration over time.
14 Performance of Novel Blood Based Biomarkers of Alzheimer's Disease is Dependent on Renal Functioning
- Corey J Bolton, Omair A Khan, Dandan Liu, Timothy J Hohman, Katherine A Gifford, Kaj Blennow, Henrik Zetterberg, Angela L Jefferson
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 225-226
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Objective:
Novel blood-based biomarkers for Alzheimer's disease (AD) could transform AD diagnosis in the community; however, their interpretation in individuals with medical comorbidities is not well understood. Specifically, kidney function has been shown to influence plasma levels of various brain proteins. This study sought to evaluate the effect of one common marker of kidney function (estimated glomerular filtration rate (eGFR)) on the association between various blood-based biomarkers of AD/neurodegeneration (glial fibrillary acidic protein (GFAP), neurofilament light (NfL), amyloid-b42 (Ab42), total tau) and established CSF biomarkers of AD (Ab42/40 ratio, tau, phosphorylated-tau (p-tau)), neuroimaging markers of AD (AD-signature region cortical thickness), and episodic memory performance.
Participants and Methods:Vanderbilt Memory and Aging Project participants (n=329, 73±7 years, 40% mild cognitive impairment, 41% female) completed fasting venous blood draw, fasting lumbar puncture, 3T brain MRI, and neuropsychological assessment at study entry and at 18-month, 3-year, and 5-year follow-up visits. Plasma GFAP, Ab42, total tau, and NfL were quantified on the Quanterix single molecule array platform. CSF biomarkers for Ab were quantified using Meso Scale Discovery immunoassays and tau and p-tau were quantified using INNOTEST immunoassays. AD-signature region atrophy was calculated by summing bilateral cortical thickness measurements captured on T1-weighted brain MRI from regions shown to distinguish individuals with AD from normal cognition. Episodic memory functioning was measured using a previously developed composite score. Linear mixed-effects regression models related predictors to each outcome adjusting for age, sex, education, race/ethnicity, apolipoprotein E-e4 status, and cognitive status. Models were repeated with a blood-based biomarker x eGFR x time interaction term with follow-up models stratified by chronic kidney disease (CKD) staging (stage 1/no CKD: eGFR>90 mL/min/1.73m2, stage 2: eGFR=60-89 mL/min/1.73m2; stage 3: eGFR=44-59mL/min/1.73m2 (no participants with higher than stage 3)).
Results:Cross-sectionally, GFAP was associated with all outcomes (p-values<0.005) and NfL was associated with memory and AD-signature region cortical thickness (p-values<0.05). In predictor x eGFR interaction models, GFAP and NfL interacted with eGFR on AD-signature cortical thickness, (p-values<0.004) and Ab42 interacted with eGFR on tau, p-tau, and memory (p-values<0.03). Tau did not interact with eGFR. Stratified models across predictors showed that associations were stronger in individuals with better renal functioning and no significant associations were found in individuals with stage 3 CKD. Longitudinally, higher GFAP and NfL were associated with memory decline (p-values<0.001). In predictor x eGFR x time interaction models, GFAP and NfL interacted with eGFR on p-tau (p-values<0.04). Other models were nonsignificant. Stratified models showed that associations were significant only in individuals with no CKD/stage 1 CKD and were not significant in participants with stage 2 or 3 CKD.
Conclusions:In this community-based sample of older adults free of dementia, plasma biomarkers of AD/neurodegeneration were associated with AD-related clinical outcomes both cross-sectionally and longitudinally; however, these associations were modified by renal functioning with no associations in individuals with stage 3 CKD. These results highlight the value of blood-based biomarkers in individuals with healthy renal functioning and suggest caution in interpreting these biomarkers in individuals with mild to moderate CKD.
Real-world impact of vaccination on coronavirus disease 2019 (COVID-19) incidence in healthcare personnel at an academic medical center
- Part of
- Sarah E. Waldman, Jason Y. Adams, Timothy E. Albertson, Maya M. Juárez, Sharon L. Myers, Ashish Atreja, Sumeet Batra, Elena E. Foster, Cy V. Huynh, Anna Y. Liu, David A. Lubarsky, Victoria T. Ngo, Christian E. Sandrock, Sandra L. Taylor, Ann M. Tompkins, Stuart H. Cohen
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- Journal:
- Infection Control & Hospital Epidemiology / Volume 43 / Issue 9 / September 2022
- Published online by Cambridge University Press:
- 21 July 2021, pp. 1194-1200
- Print publication:
- September 2022
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Objective:
Coronavirus disease 2019 (COVID-19) vaccination effectiveness in healthcare personnel (HCP) has been established. However, questions remain regarding its performance in high-risk healthcare occupations and work locations. We describe the effect of a COVID-19 HCP vaccination campaign on SARS-CoV-2 infection by timing of vaccination, job type, and work location.
Methods:We conducted a retrospective review of COVID-19 vaccination acceptance, incidence of postvaccination COVID-19, hospitalization, and mortality among 16,156 faculty, students, and staff at a large academic medical center. Data were collected 8 weeks prior to the start of phase 1a vaccination of frontline employees and ended 11 weeks after campaign onset.
Results:The COVID-19 incidence rate among HCP at our institution decreased from 3.2% during the 8 weeks prior to the start of vaccinations to 0.38% by 4 weeks after campaign initiation. COVID-19 risk was reduced among individuals who received a single vaccination (hazard ratio [HR], 0.52; 95% confidence interval [CI], 0.40–0.68; P < .0001) and was further reduced with 2 doses of vaccine (HR, 0.17; 95% CI, 0.09–0.32; P < .0001). By 2 weeks after the second dose, the observed case positivity rate was 0.04%. Among phase 1a HCP, we observed a lower risk of COVID-19 among physicians and a trend toward higher risk for respiratory therapists independent of vaccination status. Rates of infection were similar in a subgroup of nurses when examined by work location.
Conclusions:Our findings show the real-world effectiveness of COVID-19 vaccination in HCP. Despite these encouraging results, unvaccinated HCP remain at an elevated risk of infection, highlighting the need for targeted outreach to combat vaccine hesitancy.
Optimal Wireless Information and Power Transfer Using Deep Q-Network
- Yuan Xing, Haowen Pan, Bin Xu, Cristiano Tapparello, Wei Shi, Xuejun Liu, Tianchi Zhao, Timothy Lu, Arpan Desai
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- Journal:
- Wireless Power Transfer / Volume 2021 / 2021
- Published online by Cambridge University Press:
- 01 January 2024, e5
- Print publication:
- 2021
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In this paper, a multiantenna wireless transmitter communicates with an information receiver while radiating RF energy to surrounding energy harvesters. The channel between the transceivers is known to the transmitter, but the channels between the transmitter and the energy harvesters are unknown to the transmitter. By designing its transmit covariance matrix, the transmitter fully charges the energy buffers of all energy harvesters in the shortest amount of time while maintaining the target information rate toward the receiver. At the beginning of each time slot, the transmitter determines the particular beam pattern to transmit with. Throughout the whole charging process, the transmitter does not estimate the energy harvesting channel vectors. Due to the high complexity of the system, we propose a novel deep Q-network algorithm to determine the optimal transmission strategy for complex systems. Simulation results show that deep Q-network is superior to the existing algorithms in terms of the time consumption to fulfill the wireless charging process.
Inhibition of BMP9 Induced Bone Formation by Salicylic-acid Polymer Capping
- Timothy M. Acri, Noah Z. Laird, Liu Hong, Jaidev L. Chakka, Kyungsup Shin, Satheesh Elangovan, Aliasger K. Salem
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- Journal:
- MRS Advances / Volume 4 / Issue 64 / 2019
- Published online by Cambridge University Press:
- 27 January 2020, pp. 3505-3512
- Print publication:
- 2019
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This work focuses on the development of a system to control the formation of bone to complement developments that have enabled potent regeneration of bony tissue. Scaffolds were fabricated with chemically modified RNA encoding for bone morphogenetic protein-9 (cmBMP9) and capped with salicylic acid (SA)-containing polymer (SAPAE). The goal was to determine if SAPAE could inhibit the formation of bone in a pilot animal study since cmBMP9 has been demonstrated to be highly effective in regenerating bone in a rat calvarial defect model. The results indicated that cmBMP9 increased bone formation (30% increase in area covered compared to control) and that SAPAE trended toward reducing the bone formation. These results suggest SAPAE could be useful as a chemical agent in reducing unwanted bone formation in implants loaded with cmBMP9.
2318 Augmenting perception through direct electrical stimulation of adult somatosensory cortex
- Yohannes Ghenbot, Andrew Richardson, Xilin Liu, Han Hao, Sam DeLuccia, Greg Boyek, Jan Van der Spiegel, Timothy Lucas
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- Journal:
- Journal of Clinical and Translational Science / Volume 2 / Issue S1 / June 2018
- Published online by Cambridge University Press:
- 21 November 2018, p. 5
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OBJECTIVES/SPECIFIC AIMS: Our main objectives are to study sensory encoding in the adult cortex and quantify rodents’ ability to use intracortical microstimulation to guide behavior. METHODS/STUDY POPULATION: Three rats were implanted with unilateral bipolar stimulating electrodes. The electrodes were connected to a wireless neural stimulator housed in the rat’s backpack. The rat’s swim path was tracked by a video camera above the circular pool, and stimulation parameters were updated in real-time based on distance from the platform. Stimulation was delivered as the distance from the platform increased. Stimulation amplitude was determined through behavioral threshold testing, and parameters ranged from 15–75 μA with 100-Hz pulse trains and 0.2-ms pulses. Rats were first challenged with the 4-platform task in which the submerged platform was randomized across 4 possible locations. This dissociated visual cues from the platform location, as rats had knowledge of the 4 possible locations, but had to use stimulation to guide them efficiently. Next, rats were tasked with the more challenging random-platform task. Visual cues were completely dissociated from the platform location by randomizing the platform location across the entire pool. Performance using the neuroprosthetic device was assessed by comparing trials when the device was on (stimulation trial) Versus off (no-stim trial) for the 2 tasks. RESULTS/ANTICIPATED RESULTS: 4-platform task: Rats visited less potential platform locations when the neuroprosthetic was on Versus off. Rats were also more likely to visit the correct platform location on their first swim trajectory when brain stimulation was delivered. When artificial cues were not available, rats had a greater chance of visiting the platform location from the previous trial. This indicated that rats relied on visuospatial memory without the neuroprosthetic. Random platform task: Performance was measured by taking the ratio of the rat’s actual path length to the optimal path length. When the neuroprosthetic was on, rats demonstrated superior performance through a smaller path to length ratio compared with when the device was off. The platform locations of catch trials were matched to a random subset of stimulation trials, permitting a paired sample t-test. Both rats had significantly shorter path lengths when the device was on. DISCUSSION/SIGNIFICANCE OF IMPACT: Rodents have excellent navigation skills that have been well studied. They have been shown to rely on multimodal sensory information from visual, olfactory, auditory, and idiothetic cues to navigate through their environment. The importance of these cues depends on both their environmental presence and task relevance. In the original Morris water maze experiment, rats use vision to form a visuospatial map of the platform location for allocentric navigation. Here, we have shown that sensory augmented rats can pick up on novel sensory information delivered through ICMS to efficiently find a hidden platform when visual cues are made irrelevant.Our results have implications for the design of the bi-directional sensorimotor neuroprosthetic. We have demonstrated that mammals can interpret artificial sensory information to guide behavior. Future directions include investigating sensory encoding in other primary sensory areas and downstream targets along the somatosensory neuraxis.
Fate of simazine in a drip-irrigated Vitis vinifera vineyard
- Fuhan Liu, Timothy S. Prather
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- Journal:
- Weed Science / Volume 48 / Issue 4 / August 2000
- Published online by Cambridge University Press:
- 20 January 2017, pp. 514-517
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To determine simazine movement and dissipation in a drip-irrigated Vitis vinifera vineyard under two irrigation schedules [ grower standard (GS) and current evaporation/transpiration (CET)], field experiments were conducted in a Hanford fine sandy loam, a soil type prone to leaching. In experiment 1, simazine was surface-applied in a 1.7-m swath down the vine row, and chloride was applied as a tracer. Total recovery of simazine was < 1.0% under the irrigation emitters 51 and 57 d after simazine application in 1997 and 1999, respectively. Simazine was not detected in the soil profile from 0 to 150 cm deep, 1.0 m from the emitters. A chloride tracer moved to a soil depth of 90 cm but not deeper. In experiment 2, simazine moved 75 cm under the emitters in 7 d but did not move deeper into the soil. Under the emitter, 28% of applied simazine was found 0 to 45 cm deep and 3% was > 45 cm deep. In experiment 3, which was conducted in the absence of irrigation, total recovery of simazine was 30% when sheltered from rain and 8% when exposed to rain. Rapid dissipation and proper irrigation management were key factors preventing deep percolation of simazine in these studies.
Associations between Verbal Learning Slope and Neuroimaging Markers across the Cognitive Aging Spectrum
- Katherine A. Gifford, Jeffrey S. Phillips, Lauren R. Samuels, Elizabeth M. Lane, Susan P. Bell, Dandan Liu, Timothy J. Hohman, Raymond R. Romano III, Laura R. Fritzsche, Zengqi Lu, Angela L. Jefferson, for the Alzheimer’s Disease Neuroimaging Initiative
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- Journal:
- Journal of the International Neuropsychological Society / Volume 21 / Issue 6 / July 2015
- Published online by Cambridge University Press:
- 29 July 2015, pp. 455-467
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A symptom of mild cognitive impairment (MCI) and Alzheimer’s disease (AD) is a flat learning profile. Learning slope calculation methods vary, and the optimal method for capturing neuroanatomical changes associated with MCI and early AD pathology is unclear. This study cross-sectionally compared four different learning slope measures from the Rey Auditory Verbal Learning Test (simple slope, regression-based slope, two-slope method, peak slope) to structural neuroimaging markers of early AD neurodegeneration (hippocampal volume, cortical thickness in parahippocampal gyrus, precuneus, and lateral prefrontal cortex) across the cognitive aging spectrum [normal control (NC); (n=198; age=76±5), MCI (n=370; age=75±7), and AD (n=171; age=76±7)] in ADNI. Within diagnostic group, general linear models related slope methods individually to neuroimaging variables, adjusting for age, sex, education, and APOE4 status. Among MCI, better learning performance on simple slope, regression-based slope, and late slope (Trial 2–5) from the two-slope method related to larger parahippocampal thickness (all p-values<.01) and hippocampal volume (p<.01). Better regression-based slope (p<.01) and late slope (p<.01) were related to larger ventrolateral prefrontal cortex in MCI. No significant associations emerged between any slope and neuroimaging variables for NC (p-values ≥.05) or AD (p-values ≥.02). Better learning performances related to larger medial temporal lobe (i.e., hippocampal volume, parahippocampal gyrus thickness) and ventrolateral prefrontal cortex in MCI only. Regression-based and late slope were most highly correlated with neuroimaging markers and explained more variance above and beyond other common memory indices, such as total learning. Simple slope may offer an acceptable alternative given its ease of calculation. (JINS, 2015, 21, 455–467)
Contributors
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- By Mitchell Aboulafia, Frederick Adams, Marilyn McCord Adams, Robert M. Adams, Laird Addis, James W. Allard, David Allison, William P. Alston, Karl Ameriks, C. Anthony Anderson, David Leech Anderson, Lanier Anderson, Roger Ariew, David Armstrong, Denis G. Arnold, E. J. Ashworth, Margaret Atherton, Robin Attfield, Bruce Aune, Edward Wilson Averill, Jody Azzouni, Kent Bach, Andrew Bailey, Lynne Rudder Baker, Thomas R. Baldwin, Jon Barwise, George Bealer, William Bechtel, Lawrence C. Becker, Mark A. Bedau, Ernst Behler, José A. Benardete, Ermanno Bencivenga, Jan Berg, Michael Bergmann, Robert L. Bernasconi, Sven Bernecker, Bernard Berofsky, Rod Bertolet, Charles J. Beyer, Christian Beyer, Joseph Bien, Joseph Bien, Peg Birmingham, Ivan Boh, James Bohman, Daniel Bonevac, Laurence BonJour, William J. Bouwsma, Raymond D. Bradley, Myles Brand, Richard B. Brandt, Michael E. Bratman, Stephen E. Braude, Daniel Breazeale, Angela Breitenbach, Jason Bridges, David O. Brink, Gordon G. Brittan, Justin Broackes, Dan W. Brock, Aaron Bronfman, Jeffrey E. Brower, Bartosz Brozek, Anthony Brueckner, Jeffrey Bub, Lara Buchak, Otavio Bueno, Ann E. Bumpus, Robert W. Burch, John Burgess, Arthur W. Burks, Panayot Butchvarov, Robert E. Butts, Marina Bykova, Patrick Byrne, David Carr, Noël Carroll, Edward S. Casey, Victor Caston, Victor Caston, Albert Casullo, Robert L. Causey, Alan K. L. Chan, Ruth Chang, Deen K. Chatterjee, Andrew Chignell, Roderick M. Chisholm, Kelly J. Clark, E. J. Coffman, Robin Collins, Brian P. Copenhaver, John Corcoran, John Cottingham, Roger Crisp, Frederick J. Crosson, Antonio S. Cua, Phillip D. Cummins, Martin Curd, Adam Cureton, Andrew Cutrofello, Stephen Darwall, Paul Sheldon Davies, Wayne A. Davis, Timothy Joseph Day, Claudio de Almeida, Mario De Caro, Mario De Caro, John Deigh, C. F. Delaney, Daniel C. Dennett, Michael R. DePaul, Michael Detlefsen, Daniel Trent Devereux, Philip E. Devine, John M. Dillon, Martin C. Dillon, Robert DiSalle, Mary Domski, Alan Donagan, Paul Draper, Fred Dretske, Mircea Dumitru, Wilhelm Dupré, Gerald Dworkin, John Earman, Ellery Eells, Catherine Z. Elgin, Berent Enç, Ronald P. Endicott, Edward Erwin, John Etchemendy, C. Stephen Evans, Susan L. Feagin, Solomon Feferman, Richard Feldman, Arthur Fine, Maurice A. Finocchiaro, William FitzPatrick, Richard E. Flathman, Gvozden Flego, Richard Foley, Graeme Forbes, Rainer Forst, Malcolm R. Forster, Daniel Fouke, Patrick Francken, Samuel Freeman, Elizabeth Fricker, Miranda Fricker, Michael Friedman, Michael Fuerstein, Richard A. Fumerton, Alan Gabbey, Pieranna Garavaso, Daniel Garber, Jorge L. A. Garcia, Robert K. Garcia, Don Garrett, Philip Gasper, Gerald Gaus, Berys Gaut, Bernard Gert, Roger F. Gibson, Cody Gilmore, Carl Ginet, Alan H. Goldman, Alvin I. Goldman, Alfonso Gömez-Lobo, Lenn E. Goodman, Robert M. Gordon, Stefan Gosepath, Jorge J. E. Gracia, Daniel W. Graham, George A. Graham, Peter J. Graham, Richard E. Grandy, I. Grattan-Guinness, John Greco, Philip T. Grier, Nicholas Griffin, Nicholas Griffin, David A. Griffiths, Paul J. Griffiths, Stephen R. Grimm, Charles L. Griswold, Charles B. Guignon, Pete A. Y. Gunter, Dimitri Gutas, Gary Gutting, Paul Guyer, Kwame Gyekye, Oscar A. Haac, Raul Hakli, Raul Hakli, Michael Hallett, Edward C. Halper, Jean Hampton, R. James Hankinson, K. R. Hanley, Russell Hardin, Robert M. Harnish, William Harper, David Harrah, Kevin Hart, Ali Hasan, William Hasker, John Haugeland, Roger Hausheer, William Heald, Peter Heath, Richard Heck, John F. Heil, Vincent F. Hendricks, Stephen Hetherington, Francis Heylighen, Kathleen Marie Higgins, Risto Hilpinen, Harold T. Hodes, Joshua Hoffman, Alan Holland, Robert L. Holmes, Richard Holton, Brad W. Hooker, Terence E. Horgan, Tamara Horowitz, Paul Horwich, Vittorio Hösle, Paul Hoβfeld, Daniel Howard-Snyder, Frances Howard-Snyder, Anne Hudson, Deal W. Hudson, Carl A. Huffman, David L. Hull, Patricia Huntington, Thomas Hurka, Paul Hurley, Rosalind Hursthouse, Guillermo Hurtado, Ronald E. Hustwit, Sarah Hutton, Jonathan Jenkins Ichikawa, Harry A. Ide, David Ingram, Philip J. Ivanhoe, Alfred L. Ivry, Frank Jackson, Dale Jacquette, Joseph Jedwab, Richard Jeffrey, David Alan Johnson, Edward Johnson, Mark D. Jordan, Richard Joyce, Hwa Yol Jung, Robert Hillary Kane, Tomis Kapitan, Jacquelyn Ann K. Kegley, James A. Keller, Ralph Kennedy, Sergei Khoruzhii, Jaegwon Kim, Yersu Kim, Nathan L. King, Patricia Kitcher, Peter D. Klein, E. D. Klemke, Virginia Klenk, George L. Kline, Christian Klotz, Simo Knuuttila, Joseph J. Kockelmans, Konstantin Kolenda, Sebastian Tomasz Kołodziejczyk, Isaac Kramnick, Richard Kraut, Fred Kroon, Manfred Kuehn, Steven T. Kuhn, Henry E. Kyburg, John Lachs, Jennifer Lackey, Stephen E. Lahey, Andrea Lavazza, Thomas H. Leahey, Joo Heung Lee, Keith Lehrer, Dorothy Leland, Noah M. Lemos, Ernest LePore, Sarah-Jane Leslie, Isaac Levi, Andrew Levine, Alan E. Lewis, Daniel E. Little, Shu-hsien Liu, Shu-hsien Liu, Alan K. L. Chan, Brian Loar, Lawrence B. Lombard, John Longeway, Dominic McIver Lopes, Michael J. Loux, E. J. Lowe, Steven Luper, Eugene C. Luschei, William G. Lycan, David Lyons, David Macarthur, Danielle Macbeth, Scott MacDonald, Jacob L. Mackey, Louis H. Mackey, Penelope Mackie, Edward H. Madden, Penelope Maddy, G. B. Madison, Bernd Magnus, Pekka Mäkelä, Rudolf A. Makkreel, David Manley, William E. Mann (W.E.M.), Vladimir Marchenkov, Peter Markie, Jean-Pierre Marquis, Ausonio Marras, Mike W. Martin, A. P. Martinich, William L. McBride, David McCabe, Storrs McCall, Hugh J. McCann, Robert N. McCauley, John J. McDermott, Sarah McGrath, Ralph McInerny, Daniel J. McKaughan, Thomas McKay, Michael McKinsey, Brian P. McLaughlin, Ernan McMullin, Anthonie Meijers, Jack W. Meiland, William Jason Melanson, Alfred R. Mele, Joseph R. Mendola, Christopher Menzel, Michael J. Meyer, Christian B. Miller, David W. Miller, Peter Millican, Robert N. Minor, Phillip Mitsis, James A. Montmarquet, Michael S. Moore, Tim Moore, Benjamin Morison, Donald R. Morrison, Stephen J. Morse, Paul K. Moser, Alexander P. D. Mourelatos, Ian Mueller, James Bernard Murphy, Mark C. Murphy, Steven Nadler, Jan Narveson, Alan Nelson, Jerome Neu, Samuel Newlands, Kai Nielsen, Ilkka Niiniluoto, Carlos G. Noreña, Calvin G. Normore, David Fate Norton, Nikolaj Nottelmann, Donald Nute, David S. Oderberg, Steve Odin, Michael O’Rourke, Willard G. Oxtoby, Heinz Paetzold, George S. Pappas, Anthony J. Parel, Lydia Patton, R. P. Peerenboom, Francis Jeffry Pelletier, Adriaan T. Peperzak, Derk Pereboom, Jaroslav Peregrin, Glen Pettigrove, Philip Pettit, Edmund L. Pincoffs, Andrew Pinsent, Robert B. Pippin, Alvin Plantinga, Louis P. Pojman, Richard H. Popkin, John F. Post, Carl J. Posy, William J. Prior, Richard Purtill, Michael Quante, Philip L. Quinn, Philip L. Quinn, Elizabeth S. Radcliffe, Diana Raffman, Gerard Raulet, Stephen L. Read, Andrews Reath, Andrew Reisner, Nicholas Rescher, Henry S. Richardson, Robert C. Richardson, Thomas Ricketts, Wayne D. Riggs, Mark Roberts, Robert C. Roberts, Luke Robinson, Alexander Rosenberg, Gary Rosenkranz, Bernice Glatzer Rosenthal, Adina L. Roskies, William L. Rowe, T. M. Rudavsky, Michael Ruse, Bruce Russell, Lilly-Marlene Russow, Dan Ryder, R. M. Sainsbury, Joseph Salerno, Nathan Salmon, Wesley C. Salmon, Constantine Sandis, David H. Sanford, Marco Santambrogio, David Sapire, Ruth A. Saunders, Geoffrey Sayre-McCord, Charles Sayward, James P. Scanlan, Richard Schacht, Tamar Schapiro, Frederick F. Schmitt, Jerome B. Schneewind, Calvin O. Schrag, Alan D. Schrift, George F. Schumm, Jean-Loup Seban, David N. Sedley, Kenneth Seeskin, Krister Segerberg, Charlene Haddock Seigfried, Dennis M. Senchuk, James F. Sennett, William Lad Sessions, Stewart Shapiro, Tommie Shelby, Donald W. Sherburne, Christopher Shields, Roger A. Shiner, Sydney Shoemaker, Robert K. Shope, Kwong-loi Shun, Wilfried Sieg, A. John Simmons, Robert L. Simon, Marcus G. Singer, Georgette Sinkler, Walter Sinnott-Armstrong, Matti T. Sintonen, Lawrence Sklar, Brian Skyrms, Robert C. Sleigh, Michael Anthony Slote, Hans Sluga, Barry Smith, Michael Smith, Robin Smith, Robert Sokolowski, Robert C. Solomon, Marta Soniewicka, Philip Soper, Ernest Sosa, Nicholas Southwood, Paul Vincent Spade, T. L. S. Sprigge, Eric O. Springsted, George J. Stack, Rebecca Stangl, Jason Stanley, Florian Steinberger, Sören Stenlund, Christopher Stephens, James P. Sterba, Josef Stern, Matthias Steup, M. A. Stewart, Leopold Stubenberg, Edith Dudley Sulla, Frederick Suppe, Jere Paul Surber, David George Sussman, Sigrún Svavarsdóttir, Zeno G. Swijtink, Richard Swinburne, Charles C. Taliaferro, Robert B. Talisse, John Tasioulas, Paul Teller, Larry S. Temkin, Mark Textor, H. S. Thayer, Peter Thielke, Alan Thomas, Amie L. Thomasson, Katherine Thomson-Jones, Joshua C. Thurow, Vzalerie Tiberius, Terrence N. Tice, Paul Tidman, Mark C. Timmons, William Tolhurst, James E. Tomberlin, Rosemarie Tong, Lawrence Torcello, Kelly Trogdon, J. D. Trout, Robert E. Tully, Raimo Tuomela, John Turri, Martin M. Tweedale, Thomas Uebel, Jennifer Uleman, James Van Cleve, Harry van der Linden, Peter van Inwagen, Bryan W. Van Norden, René van Woudenberg, Donald Phillip Verene, Samantha Vice, Thomas Vinci, Donald Wayne Viney, Barbara Von Eckardt, Peter B. M. Vranas, Steven J. Wagner, William J. Wainwright, Paul E. Walker, Robert E. Wall, Craig Walton, Douglas Walton, Eric Watkins, Richard A. Watson, Michael V. Wedin, Rudolph H. Weingartner, Paul Weirich, Paul J. Weithman, Carl Wellman, Howard Wettstein, Samuel C. Wheeler, Stephen A. White, Jennifer Whiting, Edward R. Wierenga, Michael Williams, Fred Wilson, W. Kent Wilson, Kenneth P. Winkler, John F. Wippel, Jan Woleński, Allan B. Wolter, Nicholas P. Wolterstorff, Rega Wood, W. Jay Wood, Paul Woodruff, Alison Wylie, Gideon Yaffe, Takashi Yagisawa, Yutaka Yamamoto, Keith E. Yandell, Xiaomei Yang, Dean Zimmerman, Günter Zoller, Catherine Zuckert, Michael Zuckert, Jack A. Zupko (J.A.Z.)
- Edited by Robert Audi, University of Notre Dame, Indiana
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- The Cambridge Dictionary of Philosophy
- Published online:
- 05 August 2015
- Print publication:
- 27 April 2015, pp ix-xxx
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Problematic Internet Use: Clinical Implications
- Timothy Liu, Marc N. Potenza
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- Journal:
- CNS Spectrums / Volume 12 / Issue 6 / June 2007
- Published online by Cambridge University Press:
- 07 November 2014, pp. 453-466
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Impulse-control disorders have received relatively little attention from the mental health community. An increasing awareness of the prevalence and impact of these disorders is emerging. Among impulse control disorders, problematic Internet use has been considered and examined. Prevalence estimate studies indicate that problematic Internet use is experienced across geographic locations by many individuals of diverse backgrounds. This review examines problematic Internet use from epidemiological and clinical perspectives. Clinicians should be familiar with the extent of problematic Internet use and the data regarding the efficacies and tolerabilities of available treatments.
Alteration of postprandial glucose and insulin concentrations with meal frequency and composition
- Jill A. Kanaley, Timothy D. Heden, Ying Liu, Timothy J. Fairchild
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- Journal:
- British Journal of Nutrition / Volume 112 / Issue 9 / 14 November 2014
- Published online by Cambridge University Press:
- 18 September 2014, pp. 1484-1493
- Print publication:
- 14 November 2014
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A frequent eating pattern may alter glycaemic control and augment postprandial insulin concentrations in some individuals due to the truncation of the previous postprandial period by a subsequent meal. The present study examined glucose, insulin, C-peptide and glucose-dependent insulinotropic peptide (GIP) responses in obese individuals when meals were ingested in a high-frequency pattern (every 2 h, 6M) or in a low-frequency pattern (every 4 h, 3M) over 12 h. It also examined these postprandial responses to high-frequency, high-protein meals (6MHP). In total, thirteen obese subjects completed three 12 h study days during which they consumed 6276 kJ (1500 kcal): (1) 3M – 15 % protein and 65 % carbohydrate; (2) 6M – 15 % protein and 65 % carbohydrate; (3) 6MHP – 45 % protein and 35 % carbohydrate. Blood samples were collected every 10 min and analysed for glucose, insulin, C-peptide and GIP. Insulin total AUC (tAUC) and peak insulin concentrations (P< 0·05) were higher in the 3M condition than in the 6M condition, but there were no differences in glucose tAUC between the conditions. The 6MHP regimen (glucose: 3569 (se 83) mmol/l × min (64·3 (se 1·5) g/dl × min), insulin: 1·577 (se 0·146) pmol/l (22·7 (se 2·1) μIU/dl) for 12 h) lowered glucose and insulin excursions more so over 12 h than either the 3M regimen (glucose: 3913 (se 78) mmol/l × min (70·5 (se 1·4) g/dl × min), insulin: 2·195 (se 0·146) pmol/l × min (31·6 (se 2·1) μIU/dl × min) for 12 h) or the 6M regimen (glucose: 3902 (se 83) mmol/l × min (70·3 (se 1·5) g/dl × min), insulin: 1·861 (se 0·174) pmol/l × min (26·8 (se 2·5) μIU/dl × min) for 12 h; P< 0·01). Insulin secretion, GIP concentrations and the glucose:insulin ratio were not altered by meal frequency or composition. In obese subjects, ingestion of meals in a low-frequency pattern does not alter glucose tAUC, but increases postprandial insulin responses. The substitution of carbohydrates with protein in a frequent meal pattern results in tighter glycaemic control and reduced postprandial insulin responses.
High-Resolution Radial Distribution Function of Pure Ion-Implanted Amorphous Silicon Measured Using Tilted-Illumination Selected-Area Electron Diffraction
- Alexander Gorecki, Amelia C.Y. Liu, Timothy C. Petersen
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- Journal:
- Microscopy and Microanalysis / Volume 20 / Issue 1 / February 2014
- Published online by Cambridge University Press:
- 28 November 2013, pp. 50-54
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- February 2014
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High-resolution radial distribution functions of as-implanted and thermally relaxed amorphous silicon created by ion implantation were measured using tilted-illumination selected area electron diffraction at room temperature. The diffracted intensities were measured out to a maximum scattering vector 2 sin(θ)/λ of 3.3–3.7 Å−1. The volume-averaged pair-correlation statistics of as-implanted and relaxed ion-implanted amorphous silicon are virtually indistinguishable with coordination numbers of 3.7 ± 0.3 and 3.9 ± 0.3 (for neighbors closer than 3 Å) and average bond angles of 109 ± 0.5° and 110 ± 0.6°, respectively. The atomic rearrangements in ion-implanted amorphous silicon due to a low temperature anneal are subtle.
Development and evaluation of the Oxford WebQ, a low-cost, web-based method for assessment of previous 24 h dietary intakes in large-scale prospective studies
- Bette Liu, Heather Young, Francesca L Crowe, Victoria S Benson, Elizabeth A Spencer, Timothy J Key, Paul N Appleby, Valerie Beral
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- Journal:
- Public Health Nutrition / Volume 14 / Issue 11 / November 2011
- Published online by Cambridge University Press:
- 01 June 2011, pp. 1998-2005
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Objectives
To describe the development of the Oxford WebQ, a web-based 24 h dietary assessment tool developed for repeated administration in large prospective studies; and to report the preliminary assessment of its performance for estimating nutrient intakes.
DesignWe developed the Oxford WebQ by repeated testing until it was sufficiently comprehensive and easy to use. For the latest version, we compared nutrient intakes from volunteers who completed both the Oxford WebQ and an interviewer-administered 24 h dietary recall on the same day.
SettingOxford, UK.
SubjectsA total of 116 men and women.
ResultsThe WebQ took a median of 12·5 (interquartile range: 10·8–16·3) min to self-complete and nutrient intakes were estimated automatically. By contrast, the interviewer-administered 24 h dietary recall took 30 min to complete and 30 min to code. Compared with the 24 h dietary recall, the mean Spearman's correlation for the 21 nutrients obtained from the WebQ was 0·6, with the majority between 0·5 and 0·9. The mean differences in intake were less than ±10 % for all nutrients except for carotene and vitamins B12 and D. On rare occasions a food item was reported in only one assessment method, but this was not more frequent or systematically different between the methods.
ConclusionsCompared with an interviewer-based 24 h dietary recall, the WebQ captures similar food items and estimates similar nutrient intakes for a single day's dietary intake. The WebQ is self-administered and nutrients are estimated automatically, providing a low-cost method for measuring dietary intake in large-scale studies.
MEASURING EVERYDAY RACIAL/ETHNIC DISCRIMINATION IN HEALTH SURVEYS: How Best to Ask the Questions, in One or Two Stages, Across Multiple Racial/Ethnic Groups?1
- Salma Shariff-Marco, Nancy Breen, Hope Landrine, Bryce B. Reeve, Nancy Krieger, Gilbert C. Gee, David R. Williams, Vickie M. Mays, Ninez A. Ponce, Margarita Alegría, Benmei Liu, Gordon Willis, Timothy P. Johnson
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- Journal:
- Du Bois Review: Social Science Research on Race / Volume 8 / Issue 1 / Spring 2011
- Published online by Cambridge University Press:
- 15 April 2011, pp. 159-177
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While it is clear that self-reported racial/ethnic discrimination is related to illness, there are challenges in measuring self-reported discrimination or unfair treatment. In the present study, we evaluate the psychometric properties of a self-reported instrument across racial/ethnic groups in a population-based sample, and we test and interpret findings from applying two different widely-used approaches to asking about discrimination and unfair treatment. Even though we found that the subset of items we tested tap into a single underlying concept, we also found that different groups are more likely to report on different aspects of discrimination. Whether race is mentioned in the survey question affects both frequency and mean scores of reports of racial/ethnic discrimination. Our findings suggest caution to researchers when comparing studies that have used different approaches to measure racial/ethnic discrimination and allow us to suggest practical empirical guidelines for measuring and analyzing racial/ethnic discrimination. No less important, we have developed a self-reported measure of recent racial/ethnic discrimination that functions well in a range of different racial/ethnic groups and makes it possible to compare how racial/ethnic discrimination is associated with health disparities among multiple racial/ethnic groups.
Contributors
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- By Gregory S. Aaen, Maria Pia Amato, Laura J. Balcer, Brenda Banwell, Amit Bar-Or, Khurram Bashir, Anita L. Belman, Susan Bennett, Dorothée Chabas, Tanuja Chitnis, Russell C. Dale, Angelo Ghezzi, Jin S. Hahn, Folker Hanefeld, Deborah Hertz, R. Q. Hintzen, Sunny Im-Wang, Laura J. Julian, Lauren B. Krupp, Nancy L. Kuntz, Grant T. Liu, Timothy Lotze, Andrew McKeon, Maria Milazzo, Ellen M. Mowry, Jayne Ness, Frank S. Pidcock, Immacolata Plasmati, Daniela Pohl, Christel Renoux, Moses Rodriguez, Martino Ruggieri, A. D. Sadovnick, Guillaume Sébire, Isabella Simone, Bruno P. Soares, Jonathan Strober, Esther Tantsis, Marc Tardieu, Silvia Tenembaum, Maria Trojano, Sunita Venkateswaran, Amy T. Waldman, Emmanuelle L. Waubant, Bianca Weinstock-Guttman, Max Wintermark, E. Ann Yeh
- Edited by Dorothée Chabas, University of California, San Francisco, Emmanuelle L. Waubant, University of California, San Francisco
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- Book:
- Demyelinating Disorders of the Central Nervous System in Childhood
- Published online:
- 11 April 2011
- Print publication:
- 17 March 2011, pp vii-ix
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