Postural disturbance and vection when viewing visual stimulus oscillating in roll and fore-and-aft directions : effects of frequency and peak velocity

2008 ◽  
Author(s):  
Eric Ho Chi Chow
Keyword(s):  
Visual Stimulus ◽  
Peak Velocity ◽  
Postural Disturbance

Record Wear Studies by Scanning Electron Microscopy

1968 ◽  
Vol 26 ◽  
pp. 364-365
Author(s):  
M.D. Coutts ◽  
E.R. Levin ◽  
J.G. Woodward
Keyword(s):  
Electron Microscopy ◽  
Constant Velocity ◽  
Peak Velocity ◽  
Great Depth ◽  
Depth Of Focus ◽  
Sweep Frequency ◽  
Transmission Electron ◽  
Test Record ◽  
Lateral Mode ◽  
Scanning Electron

While record grooves have been studied by transmission electron microscopy with replica techniques, and by optical microscopy, the former are cumbersome and restricted and the latter limited by lack of depth of focus and resolution at higher magnification. With its great depth of focus and ease in specimen manipulation, the scanning electron microscope is admirably suited for record wear studies.A special RCA sweep frequency test record was used with both lateral and vertical modulation bands. The signal is a repetitive, constant-velocity sweep from 2 to 20 kHz having a duration and repetitive rate of approximately 0.1 sec. and a peak velocity of 5.5 cm/s.A series of different pickups and numbers of plays were used on vinyl records. One centimeter discs were then cut out, mounted and coated with 200 Å of gold to prevent charging during examination. Wear studies were made by taking micrographs of record grooves having 1, 10 and 50 plays with each stylus and comparing with typical “no-play” grooves. Fig. 1 shows unplayed grooves in a vinyl pressing with sweep-frequency modulation in the lateral mode.

VISUAL STIMULUS REDINTEGRATION IN THE CHIMPANZEE.

1966 ◽  
Author(s):  
DONALD N. FARRER ◽  
JIM MILNER
Keyword(s):  
Visual Stimulus

Gaze and Postural Coupling to Visual Stimulus Oscillations of Complex Motion Organization

2012 ◽  
Author(s):  
Joshua Haworth ◽  
Nathaniel Hunt ◽  
Yawen Yu ◽  
Nicholas Stergiou
Keyword(s):  
Visual Stimulus ◽  
Complex Motion

Visual stimulus-seeking in dark-reared kittens

1976 ◽  
Author(s):  
P. C. Dodwell ◽  
B. N. Timney ◽  
V. F. Emerson
Keyword(s):  
Visual Stimulus

Urine Albumin to Creatinine Ratio and Echocardiographic Left Ventricular Structure and Function in Patients with Essential Hypertension

2011 ◽  
Vol 9 (2) ◽  
pp. 90 ◽  
Author(s):  
Rohola Hemmati ◽  
Mojgan Gharipour ◽  
Hasan Shemirani ◽  
Alireza Khosravi ◽  
Elham Khosravi ◽  
...  
Keyword(s):  
Essential Hypertension ◽  
Peak Velocity ◽  
Left Ventricular ◽  
Lv Function ◽  
Creatinine Ratio ◽  
Uncomplicated Hypertension ◽  
Urine Albumin ◽  
Lv Dysfunction ◽  
Mitral Annulus Velocity ◽  
Lv Mass

Background:Appearance of microalbuminuria, particularly in patients with hypertension, might be associated with a higher prevalence of left ventricular (LV) dysfunction and geometric abnormalities. This study was undertaken to determine whether high urine albumin to creatinine ratio (UACR) as a sensitive marker for microalbuminuria can be associated with LV hypertrophy (LVH) and systolic and diastolic LV dysfunction.Methods:The study population consisted of 125 consecutive patients with essential uncomplicated hypertension. Urine albumin and creatinine concentration was determined by standard methods. LVH was defined as a LV mass index >100 g/m2 of body surface area in women and >130 g/m2 in men. Echocardiographic LV systolic and diastolic parameters were measured.Results:The prevalence of microalbuminuria in patients with essential hypertension was 5.6 %. UACR was significantly no different in patients with LVH than in patients with normal LV geometry (21.26 ± 31.55 versus 17.80 ± 24.52 mg/mmol). No significant correlation was found between UACR measurement and systolic and diastolic function parameters, including early to late diastolic peak velocity (E/A) ratio (R=-0.192, p=0.038), early diastolic peak velocity to early mitral annulus velocity (E/E') ratio (R=-0.025, p=0.794), LV ejection fraction (R=0.008, p=0.929), and LV mass (R=-0.132, p=0.154). According to the receiver operator characteristic (ROC) curve analysis, UACR measurement was not an acceptable indicator of LVH with areas under the ROC curves 0.514 (95 % confidence interval 0.394–0.634). The optimal cut-off value for UACR for predicting LVH was identified at 9.4, yielding a sensitivity of 51.6 % and a specificity of 48.3 %.Conclusion:In patients with uncomplicated essential hypertension, abnormal systolic and diastolic LV function and geometry cannot be effectively predicted by the appearance of microalbuminuria.

P2549The cardiovascular predictors of clinical outcomes in patients after ischemic stroke of undetermined etiology

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
A Bielecka-Dabrowa ◽  
P Gasiorek ◽  
A Sakowicz ◽  
M Banach
Keyword(s):  
Ischemic Stroke ◽  
Independent Predictor ◽  
Reference Group ◽  
Peak Velocity ◽  
Recurrent Stroke ◽  
Mitral Annular Velocity ◽  
Kaplan Meier ◽  
Unfavourable Prognosis ◽  
Undetermined Etiology

Abstract Purpose The study aimed to identify echocardiographic, hemodynamic and biochemical predictors of unfavourable prognosis after ischemic strokes of undetermined etiology (ESUS) in patients (pts) at age <65. Methods Out of 520 ischemic stroke pts we selected 64 pts diagnosed with ESUS [mean age 54 (SD: 47–58) years, 42% males] and additional 36 without stroke but with similar risk profile, which were treated as a reference group [age 53 (SD: 47–58) years, 61% males]. All pts underwent echocardiography, non-invasive assessment of hemodynamic parameters using SphygmoCor tonometer (Atcor Med., Australia), HDL subfraction distribution using Lipoprint (Quantimetrix) as well as measurements of selected biomarkers. Follow-up was 12 months. Results At 12-month follow-up 9% of patients had died, and recurrent ischemic stroke also occurred in 9% of patients - only in the ESUS group (Figure). Patients who died had significantly lower levels of LDL and HDL cholesterol (included HDL-8 and -9 subfractions) and higher level of triglicerides (p=0.01, p=0.01, and p=0.02; respectively), lower level of adiponectin (p=0.01), lower value of mean early diastolic (E') mitral annular velocity (p=0.04) and lower diastolic blood pressure (p=0.04). The atrial fibrillation (AF) occurred in 10% of pts during the 12 months (log-rang, p=0.254) (Figure). The log-rank test showed that ESUS group had a significantly poorer outcome of AF in the first 2 months after hospitalization compared to reference group (11% vs 5%, p=0.041). Based on a Kaplan-Meier analysis, the outcome of re-hospitalizationin the 1st year was 28% (18/64) in the ESUS group and 17% (6/36); log-rank, p=0.058. In the multivariate analysis mean early diastolic (E') mitral annular velocity (odds ratio [OR] 0.75, 95% confidence interval [CI]: 0.6–0.94; p=0.01) was significantly associated with CV hospitalizations assessed at 12-month follow-up. The only independent predictor of AF occurrence in the 12-month follow-up was lower value of Tissue Doppler-derived right ventricular systolic excursion velocity S' (OR 0.65, 95% Cl 0.45–0.93; p=0.01). The only independent predictor of recurrent stroke was the ratio of peak velocity of early diastolic transmitral flow to peak velocity of early diastolic mitral annular motion as determined by pulsed wave Doppler (E/E') (OR 0.75, 95% CI: 0.6–0.94; p=0.01). E/E' ratio was also independently associated with composite endpoint consisting of death, hospitalization and recurrent stroke (OR 1.90, 95% CI 1.1–3.2, p=0.01). Kaplan-Meier Analysis - survival and AF Conclusions The indices of diastolic dysfunction are significantly associated with unfavourable prognosis after ESUS. There is a robust role for outpatient cardiac monitoring especially during first 2 months after ESUS to detect potential AF. Acknowledgement/Funding The study was financed by research grants no. 502-03/5-139-02/502-54-229-18 of the Medical University of Lodz

scholarly journals Visual stimulus complexity and food vs. food alone as rewards for rats

1965 ◽  
Vol 3 (1-12) ◽  
pp. 403-404 ◽  
Author(s):  
R. B. May ◽  
K. L. Beauchamp ◽  
S. Pollock
Keyword(s):  
Visual Stimulus ◽  
Stimulus Complexity
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