scholarly journals The perceived position of a moving object is reset by temporal, not spatial limits

2021 ◽  
Author(s):  
Sirui Liu ◽  
Peter Ulrich Tse ◽  
Patrick Cavanagh
Keyword(s):  
Path Length ◽  
Moving Object ◽  
Path Segment ◽  
Position Errors ◽  
Constant Rate ◽  
Physical Position ◽  
Position Shift ◽  
Perceived Motion ◽  
Internal Texture ◽  
Over Time

When the internal texture of a Gabor patch drifts orthogonally to its physical path, its perceived motion deviates dramatically from its physical path. The local position shifts accumulate to such an extent that a 45 deg oblique physical path appears to be vertical. However, at some point, a limit is reached and the path resets back to its veridical location, whereupon a new accumulation starts, making the new perceived path segment appear parallel to the pre-reset segment, but offset horizontally from it. Here, we tested whether spontaneous resets of this motion-induced position shift depend on the time or the distance over which position errors accrue, or both. We introduced a temporal gap in the middle of the path that forced the illusory path to reset back to its veridical physical position. This gap-triggered reset allowed us to measure the magnitude of the illusory offset up to that point. We found that perceived offset was less than expected for the angle of illusory drift, indicating that spontaneous resets had occurred prior to the gap-induced reset. The position offset decreased when the pre-gap duration increased but approximately doubled when the path length doubled. This pattern of perceived offsets is best accounted for by spontaneous resets that occur randomly over time at a constant rate, independently of the distance traveled. Our results suggest a temporal, not spatial, limit for the accumulation of position errors that underlies this illusion.

scholarly journals Kinetics of Anti-SARS-CoV-2 Antibody Responses 3 Months Post Complete Vaccination with BNT162b2; A Prospective Study in 283 Health Workers

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1942
Author(s):  
Evangelos Terpos ◽  
Ioannis P. Trougakos ◽  
Vangelis Karalis ◽  
Ioannis Ntanasis-Stathopoulos ◽  
Sentiljana Gumeni ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Health Workers ◽  
Antibody Responses ◽  
Healthy Individuals ◽  
Younger Age ◽  
Constant Rate ◽  
Rate Of Decline ◽  
A Prospective Study ◽  
Kinetics Of ◽  
Over Time

The aim of this study was to investigate the kinetics of neutralizing antibodies (NAbs) and anti-SARS-CoV-2 anti-S-RBD IgGs up to three months after the second vaccination dose with the BNT162b2 mRNA vaccine. NAbs and anti-S-RBD levels were measured on days 1 (before the first vaccine shot), 8, 22 (before the second shot), 36, 50, and three months after the second vaccination (D111) (NCT04743388). 283 health workers were included in this study. NAbs showed a rapid increase from D8 to D36 at a constant rate of about 3% per day and reached a median (SD) of 97.2% (4.7) at D36. From D36 to D50, a slight decrease in NAbs values was detected and it became more prominent between D50 and D111 when the rate of decline was determined at −0.11 per day. The median (SD) NAbs value at D111 was 92.7% (11.8). A similar pattern was also observed for anti-S-RBD antibodies. Anti-S-RBDs showed a steeper increase during D22–D36 and a lower decline rate during D36–D111. Prior COVID-19 infection and younger age were associated with superior antibody responses over time. In conclusion, we found a persistent but declining anti-SARS-CoV-2 humoral immunity at 3 months following full vaccination with BNT162b2 in healthy individuals.

scholarly journals Technical Note: Calibration instrument for the krypton hygrometer KH20

2012 ◽  
Vol 5 (1) ◽  
pp. 1695-1715
Author(s):  
T. Foken ◽  
H. Falke
Keyword(s):  
Water Vapour ◽  
Low Temperatures ◽  
Path Length ◽  
Motor System ◽  
Humidity Sensor ◽  
Technical Note ◽  
Stepper Motor ◽  
High Altitudes ◽  
Over Time

Abstract. A calibration instrument for krypton hygrometers (KH20, Campbell Sci.) with variable path length is presented. This unit allows for in-situ calibrations of the krypton hygrometer, which is typically not very stable over time, during measuring campaigns. It was constructed mainly for application at high altitudes and low temperatures, where further improvements are needed to the IR-hygrometers which are normally used. The changing path length requires that a changing concentration of the absorber be simulated. Because oxygen absorbs more strongly than water vapour, the calibration is made against oxygen and transferred to water vapour. The design of the calibration instrument is made as one unit containing a stepper motor system, PC and humidity sensor. For the calibration, it is necessary to install the krypton hygrometer on this unit.

scholarly journals Technical Note: Calibration device for the krypton hygrometer KH20

2012 ◽  
Vol 5 (8) ◽  
pp. 1861-1867 ◽  
Author(s):  
T. Foken ◽  
H. Falke
Keyword(s):  
Water Vapour ◽  
Low Temperatures ◽  
Path Length ◽  
Motor System ◽  
Humidity Sensor ◽  
Technical Note ◽  
Stepper Motor ◽  
Calibration Device ◽  
Over Time

Abstract. A calibration device for krypton hygrometers (KH20, Campbell Scientific, Inc.) with variable path length is presented. This unit allows for in-situ calibrations of the krypton hygrometer, which is typically not very stable over time, during measuring campaigns. It was constructed mainly for application at high altitudes and low temperatures, where further improvements are needed to the IR-hygrometers which are normally used. The changing path length requires that a changing concentration of the absorber be simulated. Because oxygen absorbs more strongly than water vapour, the calibration is made against oxygen and transferred to water vapour. The design of the calibration instrument is made as one unit containing a stepper motor system, PC and humidity sensor. For the calibration, it is necessary to install the krypton hygrometer on this unit.

Foreign Trade, Aid and Economic Growth in Less-Developed Countries by Gunnar Floystad. Oslo: Scandinavian University Books, Universitetsforlaget, 1968.

1968 ◽  
Vol 8 (2) ◽  
pp. 307-308
Author(s):  
Mohammad Anisur Rahman
Keyword(s):  
Economic Growth ◽  
Foreign Trade ◽  
Foreign Aid ◽  
Mainland China ◽  
Developed Countries ◽  
Capital Inflows ◽  
Less Developed Countries ◽  
Constant Rate ◽  
Simple Exponential Function ◽  
Over Time

Gunnar Floystad's Foreign Trade, Aid and Economic Growth is concerned with the interrelations between foreign trade, foreign aid and economic growth of a group of less developed countries (LDC) comprising all of Latin America, Africa, the Middle East and Asia, excluding USSR, Japan and Mainland China. The book is divided into two parts: Part One uses a model of trade, aid and growth to deduce a relationship between GNP, exports and net capital inflows of the LDC. Assuming exports to be given exogenously and net capital inflows to grow at a constant rate over time, growth of GNP is projected corresponding to alternative postulates about growth of exports and growth of net capital inflows via the simple exponential function, E(t) = M0 [X(t) + B(t)]B, where E, X and B stand for GNP, exports and net capital inflows respectively, and M is a constant. Part Two analyses in some details the export prospects for a list of traditional products currently exported from LDC to developed countries.

Position Perception: Influence of Motion With Displacement Dissociated From the Influence of Motion Alone

2008 ◽  
Vol 100 (5) ◽  
pp. 2472-2476 ◽  
Author(s):  
Daniel Linares ◽  
Alex O. Holcombe
Keyword(s):  
Moving Object ◽  
Spatial Lag ◽  
Position Shift ◽  
Moving Pattern

When humans view a moving object, the spatial lag in perception expected from neural delays may be partially corrected by motion mechanisms biasing perceived position. The drifting-Gabor illusion seems to support this view: the perceived location of a static envelope filled with a moving pattern is shifted in the direction of motion. To test whether this shifting mechanism also extrapolates the position of moving displacing objects, we compared the perceptual position shift for drifting versus displacing Gabors when the motion is toward the fovea and when the motion is away from the fovea. For displacing Gabors, the shift was much greater for motion toward the fovea, whereas for drifting Gabors, the shift was greater for motion away from the fovea. This dissociation suggests that the illusions are caused by different mechanisms.

scholarly journals Attention updates the perceived position of moving objects

2019 ◽  
Author(s):  
Ryohei Nakayama ◽  
Alex O. Holcombe
Keyword(s):  
Moving Objects ◽  
Moving Object ◽  
Conscious Perception ◽  
Attention Shift ◽  
Correct Position ◽  
Privileged Access ◽  
Actual Position ◽  
Position Shift

AbstractThe information used by conscious perception may be somewhat different from that which drives certain actions. In support of this notion, recent studies reported that although internal grating motion can accumulate over seconds into a large illusory position shift, this position shift is not reflected in saccade targeting (action). Another possibility however is that rather than saccades and other actions having privileged access to the correct position, the attention shift thought to precede saccades resets the accumulated position shift to zero. Here we found that the accumulation of illusory position shift can be reset by transients near the moving object and also by the observer pressing a button at the time the object is perceived to reach a particular position. This creates a striking impression of the object jumping back to near its actual position. These results suggest that both stimulus-driven attention and attention associated with control of action may update the perceived position of moving objects and mediate the previously reported dissociation between conscious perception and saccades.

Relative pronouns in it-clefts: The last seven centuries

1994 ◽  
Vol 6 (2) ◽  
pp. 179-200 ◽  
Author(s):  
Catherine N. Ball
Keyword(s):  
Relative Frequency ◽  
Relative Clauses ◽  
Constant Rate ◽  
Restrictive Relative Clauses ◽  
Over Time ◽  
Relative Pronouns

ABSTRACTIt has often been claimed that it-cleft complements differ syntactically from restrictive relative clauses. Alleged differences in the distribution and relative frequency of wh-forms in the two clause types are generally offered to support this view, but such claims have not been empirically verified. In this study, we examine synchronic and diachronic data for clefts and relative clauses and show that the major claims are unsupported. The diachronic data further show that cleft complements and restrictive relative clauses have changed together over time and at the same rate. On the constant rate hypothesis, the evidence supports the position that the two clause types are not syntactically distinct.

scholarly journals Meridian interference reveals neural locus of motion-induced position shifts

2018 ◽  
Vol 119 (6) ◽  
pp. 2091-2099 ◽  
Author(s):  
Sirui Liu ◽  
Peter U. Tse ◽  
Patrick Cavanagh
Keyword(s):  
Eye Movements ◽  
Neural Mechanisms ◽  
Motion Path ◽  
Vertical Meridian ◽  
Behavioral Consequence ◽  
Integration Period ◽  
Position Shift ◽  
Internal Texture ◽  
Anatomical Constraints

When a Gabor patch moves along a path in one direction while its internal texture drifts orthogonally to this path, it can appear to deviate from its physical path by 45° or more. This double-drift illusion is different from other motion-induced position shift effects in several ways: it has an integration period of over a second; the illusory displacement that accumulates over a second or more is orthogonal to rather than along the motion path; the perceptual deviations are much larger; and they have little or no effect on eye movements to the target. In this study we investigated the underlying neural mechanisms of the motion integration and position processing for this double-drift stimulus by testing possible anatomical constraints on its magnitude. We found that the illusion was reduced at the vertical and horizontal meridians when the perceptual path would cross or be driven toward the meridian, but not at other locations or other motion directions. The disruption of the accumulation of the position error at both the horizontal and vertical meridians suggests a central role of quadrantic areas in the generation of this type of motion-induced position shift. NEW & NOTEWORTHY The remarkably strong double-drift illusion is disrupted at both the vertical and horizontal meridians. We propose that this finding is the behavioral consequence of the anatomical gaps at both meridians, suggesting that neural areas with quadrantic representations (e.g., V2, V3) are the initial locus of this motion-induced position shift. This result rules out V1 as the source of the illusion because it has an anatomical break only at the vertical meridian.

scholarly journals Be like and the Constant Rate Effect: from the bottom to the top of the S-curve

2020 ◽  
pp. 1-44
Author(s):  
MATT HUNT GARDNER ◽  
DEREK DENIS ◽  
MARISA BROOK ◽  
SALI A. TAGLIAMONTE
Keyword(s):  
United Kingdom ◽  
Real Time ◽  
Rate Effect ◽  
Saturation Point ◽  
Constant Rate ◽  
English Speaking ◽  
S Curve ◽  
English Speaking World ◽  
Over Time ◽  
Logistic Modelling

The be like quotative emerged rapidly around the English-speaking world and has quickly saturated the quotative systems of young speakers in multiple countries. We study be like (and its covariants) in two communities – Toronto, Canada, and York, United Kingdom – in apparent time and at two separate points in real time. We trace the apparent-time trajectory of be like and its covariants from inception to saturation. We take advantage of the prodigious size of our dataset to examine understudied aspects of the linguistic factors that condition quotative variation. Building on earlier suggestions (Cukor-Avila 2002; Durham et al.2012) that be like might show patterning over time consistent with the Constant Rate Effect (or CRE, Kroch 1989), we argue that the CRE does indeed apply to the rise of be like, but needs to be handled with care. Logistic modelling assumes that the top of the S-curve is located at 100 per cent of a given variable context. In the case of be like, the saturation point is nearer 75–85 per cent, with minor variants retaining small semantic footholds in the system. In conjunction with our analysis, we suggest how to adapt the predictions of the CRE to changes likely to lead to saturation but not categorical use.

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