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"Dewey, John A."
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Still waters run deep : young women's writing from Russia
Frank, unsparing, and varied stories by women in their twenties and thirties reveal the evolution of women's consciousness in Russia through two decades of violent social upheaval-- including the dramatic monologue of a teenage girl who grew up in an orphanage; an escape to the Altai Mountains and the mysterious local rites and lore; the seamy side of Siberian business and a young man's failure to get to grips with it; the tricky backstage life of a provincial theater; the private life of a wealthy family which mirrors the social stratification in Russian society today.
Do Implicit and Explicit Measures of the Sense of Agency Measure the Same Thing?
2014
The sense of agency (SoA) refers to perceived causality of the self, i.e. the feeling of causing something to happen. The SoA has been probed using a variety of explicit and implicit measures. Explicit measures include rating scales and questionnaires. Implicit measures, which include sensory attenuation and temporal binding, use perceptual differences between self- and externally generated stimuli as measures of the SoA. In the present study, we investigated whether the different measures tap into the same self-attribution processes by determining whether individual differences on implicit and explicit measures of SoA are correlated. Participants performed tasks in which they triggered tones via key presses (operant condition) or passively listened to tones triggered by a computer (observational condition). We replicated previously reported effects of sensory attenuation and temporal binding. Surprisingly the two implicit measures of SoA were not significantly correlated with each other, nor did they correlate with the explicit measures of SoA. Our results suggest that some explicit and implicit measures of the SoA may tap into different processes.
Journal Article
Cognitive Flexibility Predicts Live-Fire Rifle Marksmanship in Airborne Cadets: A Pilot Study
by
Lachowicz, Maciej
,
Jamro, Dariusz
,
Lucena, Rui
in
Accuracy
,
Army Combat Fitness Test
,
Bayesian analysis
2025
Background: Executive functions may underpin performance in live-fire tasks, whereas evidence for global physical fitness is mixed. We quantified the associations between cognitive flexibility (CF), inhibitory control (IC), overall physical fitness, and rifle marksmanship in cadets, and derived a parsimonious predictive model. Methods: Twenty second-year male airborne cadets (mean age 21.7 ± 2.2 years) completed a live-fire Basic Rifle Marksmanship (BRM) qualification (40 targets at 50–300 m); the Color Trails Test (CTT-1 and CTT-2; interference index) to index CF and processing speed; a stop-signal–style task (CogniFit) to assess IC indexed by NO-GO accuracy and GO-trial response time; and the Army Combat Fitness Test (ACFT). Associations were examined with Spearman correlations. Multiple linear regression with backward elimination and Bayesian model comparison evaluated predictive models. Results: Faster CTT-2 performance was associated with higher BRM scores (ρ = −0.48, p = 0.032), with a similar association for CTT-1 (ρ = −0.46, p = 0.042). The best-fitting regression model included CTT-2 time and IC–accuracy (adjusted R2 = 0.345; RMSE = 7.03), with CTT-2 time the only significant predictor of BRM (b = −0.330, p = 0.006). Bayesian model comparison independently favored a parsimonious CTT-2–only model (P(M|data) = 0.222; BFM = 5.41; BF10 = 1.00; R2 = 0.352). ACFT scores were not significantly associated with BRM. Conclusions: CF and processing speed are key correlates of live–fire rifle marksmanship in cadets, suggesting value in integrating executive–function elements into marksmanship training. Replication in larger cohorts is warranted.
Journal Article
Relationship between BOLD amplitude and pattern classification of orientation-selective activity in the human visual cortex
by
Harrison, Stephenie A.
,
Tong, Frank
,
Kamitani, Yukiyasu
in
Adult
,
Brain
,
Brain - blood supply
2012
Orientation-selective responses can be decoded from fMRI activity patterns in the human visual cortex, using multivariate pattern analysis (MVPA). To what extent do these feature-selective activity patterns depend on the strength and quality of the sensory input, and might the reliability of these activity patterns be predicted by the gross amplitude of the stimulus-driven BOLD response? Observers viewed oriented gratings that varied in luminance contrast (4, 20 or 100%) or spatial frequency (0.25, 1.0 or 4.0cpd). As predicted, activity patterns in early visual areas led to better discrimination of orientations presented at high than low contrast, with greater effects of contrast found in area V1 than in V3. A second experiment revealed generally better decoding of orientations at low or moderate as compared to high spatial frequencies. Interestingly however, V1 exhibited a relative advantage at discriminating high spatial frequency orientations, consistent with the finer scale of representation in the primary visual cortex. In both experiments, the reliability of these orientation-selective activity patterns was well predicted by the average BOLD amplitude in each region of interest, as indicated by correlation analyses, as well as decoding applied to a simple model of voxel responses to simulated orientation columns. Moreover, individual differences in decoding accuracy could be predicted by the signal-to-noise ratio of an individual's BOLD response. Our results indicate that decoding accuracy can be well predicted by incorporating the amplitude of the BOLD response into simple simulation models of cortical selectivity; such models could prove useful in future applications of fMRI pattern classification.
► Decoding of orientation-selective activity patterns depends on visual input strength. ► Results largely follow the predictions of neurophysiological studies in animals. ► Areas V1–V3 are differentially affected by changes in contrast and spatial frequency. ► Amplitude of BOLD response can predict changes in orientation decoding accuracy. ► Predictions are enhanced by incorporating BOLD amplitudes into a simulation model.
Journal Article
Sensory attenuation of action effects due to predictive forward models: When does it transfer to observed actions?
2012
The sensory consequences of intentional actions (action effects) are often judged to be less intense compared to identical but externally generated stimuli. This phenomenon is normally explained in terms of predictive forward models within the sensorimotor system which partially inhibit predictable sensory feedback. An unsettled question is whether merely observing another agent performing a predictable action may also trigger a forward model with attendant sensory attenuation, or alternatively, if a self-generated motor signal is necessary. I conducted three experiments to investigate this question using a visual speed discrimination task. Participants judged which of two moving stimuli was faster. The first stimulus was initiated by the participant's own key press (Self), another person's key press (Other), or the computer program (Computer), and had a fixed speed. The second stimulus was always initiated by the computer and had a variable speed. The point of subjective equality (PSE) was compared for each condition. In Experiment 1 participants performed the task at their own pace. The Self condition was judged to be slower than the Other or Computer conditions, while the latter two did not differ. To control for the possibility that self-initiated movements were more temporally predictable and/or less attended than movements by other agents, in Experiment 2 the pace was controlled by go signals, and a green light followed every human or computer action to indicate that a movement was about to begin. Compared to Experiment 1, the PSE increased in all conditions, but the Self condition was still judged to be slowest and the Computer condition the fastest, while the Other condition was in between. In Experiment 3 the predictability of the action effects was manipulated independently from the agent who produced them, in order to investigate whether expectation similarly attenuates the intensity of Self and Computer-initiated action effects. Participants used two keys to initiate moves in two directions (left or right). In the Predictable group, the direction of the move matched the direction of the key press 80% of the time. In the Unpredictable group, the directions only matched 50% of the time. Self moves were only attenuated in the Predictable group. I conclude that sensory attenuation is influenced by a combination of private and shared or publicly available information, and that the influence of public information may be particularly tuned to biological agents. Furthermore action effects must be predictable to become attenuated.
Dissertation
Characterization of Parkinson’s disease using blood-based biomarkers: A multicohort proteomic analysis
by
Trojanowski, John Q.
,
Huang, Xuemei
,
Skrinak, R. Tyler
in
Aged
,
Algorithms
,
Amidohydrolases - blood
2019
Parkinson's disease (PD) is a progressive neurodegenerative disease affecting about 5 million people worldwide with no disease-modifying therapies. We sought blood-based biomarkers in order to provide molecular characterization of individuals with PD for diagnostic confirmation and prediction of progression.
In 141 plasma samples (96 PD, 45 neurologically normal control [NC] individuals; 45.4% female, mean age 70.0 years) from a longitudinally followed Discovery Cohort based at the University of Pennsylvania (UPenn), we measured levels of 1,129 proteins using an aptamer-based platform. We modeled protein plasma concentration (log10 of relative fluorescence units [RFUs]) as the effect of treatment group (PD versus NC), age at plasma collection, sex, and the levodopa equivalent daily dose (LEDD), deriving first-pass candidate protein biomarkers based on p-value for PD versus NC. These candidate proteins were then ranked by Stability Selection. We confirmed findings from our Discovery Cohort in a Replication Cohort of 317 individuals (215 PD, 102 NC; 47.9% female, mean age 66.7 years) from the multisite, longitudinally followed National Institute of Neurological Disorders and Stroke Parkinson's Disease Biomarker Program (PDBP) Cohort. Analytical approach in the Replication Cohort mirrored the approach in the Discovery Cohort: each protein plasma concentration (log10 of RFU) was modeled as the effect of group (PD versus NC), age at plasma collection, sex, clinical site, and batch. Of the top 10 proteins from the Discovery Cohort ranked by Stability Selection, four associations were replicated in the Replication Cohort. These blood-based biomarkers were bone sialoprotein (BSP, Discovery false discovery rate [FDR]-corrected p = 2.82 × 10-2, Replication FDR-corrected p = 1.03 × 10-4), osteomodulin (OMD, Discovery FDR-corrected p = 2.14 × 10-2, Replication FDR-corrected p = 9.14 × 10-5), aminoacylase-1 (ACY1, Discovery FDR-corrected p = 1.86 × 10-3, Replication FDR-corrected p = 2.18 × 10-2), and growth hormone receptor (GHR, Discovery FDR-corrected p = 3.49 × 10-4, Replication FDR-corrected p = 2.97 × 10-3). Measures of these proteins were not significantly affected by differences in sample handling, and they did not change comparing plasma samples from 10 PD participants sampled both on versus off dopaminergic medication. Plasma measures of OMD, ACY1, and GHR differed in PD versus NC but did not differ between individuals with amyotrophic lateral sclerosis (ALS, n = 59) versus NC. In the Discovery Cohort, individuals with baseline levels of GHR and ACY1 in the lowest tertile were more likely to progress to mild cognitive impairment (MCI) or dementia in Cox proportional hazards analyses adjusting for age, sex, and disease duration (hazard ratio [HR] 2.27 [95% CI 1.04-5.0, p = 0.04] for GHR, and HR 3.0 [95% CI 1.24-7.0, p = 0.014] for ACY1). GHR's association with cognitive decline was confirmed in the Replication Cohort (HR 3.6 [95% CI 1.20-11.1, p = 0.02]). The main limitations of this study were its reliance on the aptamer-based platform for protein measurement and limited follow-up time available for some cohorts.
In this study, we found that the blood-based biomarkers BSP, OMD, ACY1, and GHR robustly associated with PD across multiple clinical sites. Our findings suggest that biomarkers based on a peripheral blood sample may be developed for both disease characterization and prediction of future disease progression in PD.
Journal Article
Cochlear outer hair cell electromotility enhances organ of Corti motion on a cycle-by-cycle basis at high frequencies in vivo
by
Shera, Christopher A.
,
Dewey, James B.
,
Altoè, Alessandro
in
Acoustic Stimulation
,
Amplification
,
Animals
2021
Mammalian hearing depends on an amplification process involving prestin, a voltage-sensitive motor protein that enables cochlear outer hair cells (OHCs) to change length and generate force. However, it has been questioned whether this prestin-based somatic electromotility can operate fast enough in vivo to amplify cochlear vibrations at the high frequencies that mammals hear. In this study, we measured sound-evoked vibrations from within the living mouse cochlea and found that the top and bottom of the OHCs move in opposite directions at frequencies exceeding 20 kHz, consistent with fast somatic length changes. These motions are physiologically vulnerable, depend on prestin, and dominate the cochlea’s vibratory response to high-frequency sound. This dominance was observed despite mechanisms that clearly low-pass filter the in vivo electromotile response. Low-pass filtering therefore does not critically limit the OHC’s ability to move the organ of Corti on a cycle-by-cycle basis. Our data argue that electromotility serves as the primary high-frequency amplifying mechanism within the mammalian cochlea.
Journal Article
Orogeny Can Be Very Short
2005
In contrast to continent/continent collision, arc-continent collision generates very short-lived orogeny because the buoyancy-driven impedance of the subduction of continental lithosphere, accompanied by arc/suprasubduction-zone ophiolite obduction, is relieved by subduction polarity reversal (flip). This tectonic principle is illustrated by the early Ordovician Grampian Orogeny in the British and Irish Caledonides, in which a wealth of detailed sedimentologic, heavy mineral, and geochronologic data pin the Orogeny to a very short Arenig/Llanvirn event. The Orogeny, from the initial subduction of continental margin sediments to the end of postflip shortening, lasted $\\approx18$ million years (my). The collisional shortening, prograde-metamorphic phase of the Orogeny lasted 8 my, extensional collapse and exhumation of midcrustal rocks lasted 1.5 my, and postflip shortening lasted 4.5 my. Strain rates were a typical plate-boundary-zone 10-15. Metamorphism, to the second sillimanite isograd, with extensive partial melting, occurred within a few my after initial collision, indicating that conductive models for metamorphic heat transfer in Barrovian terrains are incorrect and must be replaced by advective models in which large volumes of mafic/ultramafic magma are emplaced, syn-tectonically, below and into evolving nappe stacks. Arc/continent collision generates fast and very short orogeny, regional metamorphism, and exhumation.
Journal Article
Two-Year Outcomes after Transcatheter or Surgical Aortic-Valve Replacement
by
Svensson, Lars G
,
Makkar, Raj R
,
Whisenant, Brian
in
Anticoagulants - adverse effects
,
Anticoagulants - therapeutic use
,
Aortic stenosis
2012
This study provides 2-year data from the PARTNER trial, in which patients with aortic stenosis received transcatheter aortic-valve replacement (TAVR) or surgical replacement. Overall mortality was similar, but paravalvular leak increased mortality in the TAVR group.
Aortic stenosis is associated with high mortality after the appearance of cardiac symptoms.
1
Nevertheless, many patients do not undergo surgical aortic-valve replacement owing to real or perceived increased risks associated with surgery.
2
–
5
Transcatheter aortic-valve replacement (TAVR) has emerged as an alternative therapy in high-risk patients with aortic stenosis.
6
–
10
Observational registries from various countries have reported 1-month and 1-year outcomes after TAVR,
11
–
14
but there are limited long-term follow-up data.
15
The Placement of Aortic Transcatheter Valves (PARTNER) trial was a randomized trial comparing TAVR with standard-of-care therapies in high-risk patients with aortic stenosis. One-year mortality outcomes from PARTNER showed . . .
Journal Article
The sole of an ophiolite; the Ordovician Bay of Islands Complex, Newfoundland
2013
The early Ordovician (c. 485 Ma) Bay of Islands Ophiolite Complex was obducted onto the Laurentian rifted margin as the fore-arc of an oceanic arc that collided with the margin during the mid-Ordovician (c. 470 Ma). The subduction zone was nucleated on an oceanic transform-fracture zone, part of whose remnants occur as the polyphase-deformed and intruded mafic and ultramafic rocks of the Coastal Complex. The ophiolite formed as a suprasubduction-zone fore-arc ophiolite at the spatial and temporal continuation of the ridge normal to the transform-fracture zone-subduction zone system and NE of a trench-trench-ridge triple junction. A two-pyroxene garnet granulite-garnet amphibolite-epidote amphibolite mafic metamorphic sole at the base of the ophiolite was generated, roughly synchronously with the ophiolite, by the metamorphism of mid-ocean ridge basalt mafic rocks in the descending slab at about 10 kbar and quickly attached to the base of the overlying ophiolite during slab flattening, and not by subduction zone extrusion. The metamorphic sole is not a metamorphic aureole at the base of a hot obducting ophiolite. Plate slip vector triangles around the triple junction, before collision and during obduction, are constructed from the orientation of dykes in the sheeted complex and the trends of structures in the high- to lower-temperature parts of the sole and the obducted nappes of oceanic and continental margin rocks beneath the ophiolite. Linear structures in the sole amphibolites trend NNW (the subduction direction); those in the greenschist-facies, obducted, oceanic and continental margin rocks trend WSW (the obduction direction).
Journal Article