scholarly journals Asymmetrical Pseudo-Extinction Phenomenon in the Illusory Line Motion

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1322
Author(s):  
Vidheya G. Del Vicario ◽  
Rossana Actis-Grosso ◽  
Nadia Bolognini ◽  
Roberta Daini
Keyword(s):  
Superior Colliculus ◽  
Spatial Attention ◽  
Opposite Direction ◽  
The Other ◽  
Exogenous Attention ◽  
White Line ◽  
Illusory Line Motion ◽  
Perceptual Asymmetry ◽  
Negative Results ◽  
Asymmetrical Effect

Illusory Line Motion (i.e., a static line, presented after a lateral cue, is perceived as movement in the opposite direction to the cue) has been used to study a phenomenon of perceptual asymmetry. We have demonstrated the presence of an illusion of leftward movement, even in the presence of bilateral symmetrical cues. We have classified this phenomenon as one of pseudo-extinction. The paradigm of the four experiments performed was always the same: a white line, briefly presented alone or preceded by one or two lateral cues (150 ms), was judged by a group of young participants to be moving either to one side or the other. The asymmetrical effect in the bilateral cue condition was observed with horizontal lines (Experiment 1 and 4), and not with vertical or oblique (Experiment 2 and 3). These results suggest that the effect is linked to the asymmetry of the horizontal spatial planum and the mechanisms of spatial attention. Experiment 4 verified whether the Illusory Line Motion involves the collicular pathway by using blue stimuli for the cues, which activate less the Superior Colliculus (SC), with negative results. We interpreted the asymmetrical pseudo-extinction phenomenon in terms of a right-space exogenous attention advantage.

scholarly journals An alternative to the rejection of observations

1932 ◽  
Vol 137 (831) ◽  
pp. 78-87 ◽  
Keyword(s):  
Standard Deviation ◽  
Continuous Function ◽  
Large Deviations ◽  
Opposite Direction ◽  
Standard Error ◽  
The Other ◽  
Cause Of Error ◽  
The Mean ◽  
Normal Law ◽  
Usual Rule

1. It is widely felt that any method of rejecting observations with large deviations from the mean is open to some suspicion. Suppose that by some criterion, such as Peirce’s and Chauvenet’s, we decide to reject observations with deviations greater than 4 σ, where σ is the standard error, computed from the standard deviation by the usual rule; then we reject an observation deviating by 4·5 σ, and thereby alter the mean by about 4·5 σ/ n , where n is the number of observations, and at the same time we reduce the computed standard error. This may lead to the rejection of another observation deviating from the original mean by less than 4 σ, and if the process is repeated the mean may be shifted so much as to lead to doubt as to whether it is really sufficiently representative of the observations. In many cases, where we suspect that some abnormal cause has affected a fraction of the observations, there is a legitimate doubt as to whether it has affected a particular observation. Suppose that we have 50 observations. Then there is an even chance, according to the normal law, of a deviation exceeding 2·33 σ. But a deviation of 3 σ or more is not impossible, and if we make a mistake in rejecting it the mean of the remainder is not the most probable value. On the other hand, an observation deviating by only 2 σ may be affected by an abnormal cause of error, and then we should err in retaining it, even though no existing rule will instruct us to reject such an observation. It seems clear that the probability that a given observation has been affected by an abnormal cause of error is a continuous function of the deviation; it is never certain or impossible that it has been so affected, and a process that completely rejects certain observations, while retaining with full weight others with comparable deviations, possibly in the opposite direction, is unsatisfactory in principle.

XXVI.—A New Method of determining the Degree of Twist in Single Threads

1907 ◽  
Vol 27 ◽  
pp. 264-268 ◽  
Author(s):  
Thomas Oliver
Keyword(s):  
Opposite Direction ◽  
The Other ◽  
New Method

The determination of the degree of twist in a folded or ply thread composed of two or more strands is an easy matter. It is merely necessary to stretch the thread between two clamps, one being fixed and the other forming the end of a bar which can be rotated about its axis. A counter is attached to indicate the number of rotations. Rotating the thread in the opposite direction to its twist ultimately brings the singles parallel to each other. This point is easily observed. If we apply this method to single yarns we are at once confronted with the difficulty that the fibres constituting the yarn cannot be reduced to exact parallelism with each other.

scholarly journals Natural infection of phlebotomines (Diptera: Psychodidae) in a visceral-leishmaniasis focus in Mato Grosso do Sul, Brazil

2007 ◽  
Vol 49 (2) ◽  
pp. 119-122 ◽  
Author(s):  
João Cezar do Nascimento ◽  
Byanca Regina de Paiva ◽  
Rosely dos Santos Malafronte ◽  
Wedson Desidério Fernandes ◽  
Eunice Aparecida Bianchi Galati
Keyword(s):  
Visceral Leishmaniasis ◽  
Natural Infection ◽  
Leishmania Species ◽  
Common Species ◽  
The Other ◽  
Lutzomyia Longipalpis ◽  
Leishmania Chagasi ◽  
Mato Grosso ◽  
Negative Results ◽  
Mato Grosso Do Sul

The main purpose of this study was to investigate natural infection by Leishmania in phlebotomine females in a visceral-leishmaniasis focus in Antonio João county in Mato Grosso do Sul State, Brazil. Between June and October 2003, the digestive tracts of 81 females captured in Aldeia Campestre, Aldeia Marangatu and Povoado Campestre were dissected. The females were separated by species, location, area and date of capture into 13 groups and kept in ethanol 70%. To identify the Leishmania species using the PCR technique, amplifications of the ribosomal-DNA (rDNA) and mini-exon genes were analyzed. Of the 81 specimens, 77 (95%) were Lutzomyia longipalpis, making this the most common species; only one specimen of each of the species Brumptomyia avellari, Evandromyia cortelezzii, Evandromyia lenti and Nyssomyia whitmani was found. Trypanosomatids were identified in eight of the nine groups of Lutzomyia longipalpis (10.39%) one group from Aldeia Campestre, one from Aldeia Marangatu and six from Povoado Campestre; of the eight groups, one from Aldeia Marangatu and another, with promastigotes forms also confirmed by dissection (1.23%) from Povoado Campestre, were identified by PCR as Leishmania chagasi (2.6%). The other groups gave negative results. These findings indicate that there is a high risk of leishmaniasis transmission in this area.

X.—Remarks on Coincidence Experiments with Visible Light

1962 ◽  
Vol 66 (2) ◽  
pp. 111-115
Author(s):  
Z. Bay ◽  
P. S. Farago
Keyword(s):  
Quantum Theory ◽  
Visible Light ◽  
The Other ◽  
Coherent Light ◽  
Quadratic Effect ◽  
Linear Effect ◽  
Negative Results ◽  
Light Beams

SynopsisAfter the detection of correlations in two coherent light beams by Hanbury Brown and Twiss, objections were raised by Brannen and Ferguson on the basis of the experiments of Adam, Janossy and Varga and their own experiments in which no correlations were detected. It is pointed out here that the different groups were looking for two entirely different effects, one being quadratic, the other one linear in the number of photons involved; the quadratic effect (discovered by Hanbury Brown and Twiss) is in agreement with quantum theory while the linear effect is not. It was shown by Purcell and by Hanbury Brown and Twiss that the choice of parameters in the experiments which gave negative results was inadequate to show the quadratic effect. It is shown in this paper that their experiments were also inadequate to decide between the existence or nonexistence of the linear effect.

Dynamics of Within-, Inter-, and Cross-Modal Attentional Modulation

2011 ◽  
Vol 105 (2) ◽  
pp. 674-686 ◽  
Author(s):  
Tetsuo Kida ◽  
Koji Inui ◽  
Emi Tanaka ◽  
Ryusuke Kakigi
Keyword(s):  
Spatial Attention ◽  
Interstimulus Interval ◽  
Temporal Dynamics ◽  
Visual Stimulation ◽  
The Other ◽  
Neural Representations ◽  
Tactile Stimuli ◽  
Sensory Modalities ◽  
The Right ◽  
Directing Attention

Numerous studies have demonstrated effects of spatial attention within single sensory modalities (within-modal spatial attention) and the effect of directing attention to one sense compared with the other senses (intermodal attention) on cortical neuronal activity. Furthermore, recent studies have been revealing that the effects of spatial attention directed to a certain location in a certain sense spread to the other senses at the same location in space (cross-modal spatial attention). The present study used magnetoencephalography to examine the temporal dynamics of the effects of within-modal and cross-modal spatial and intermodal attention on cortical processes responsive to visual stimuli. Visual or tactile stimuli were randomly presented on the left or right side at a random interstimulus interval and subjects directed attention to the left or right when vision or touch was a task-relevant modality. Sensor-space analysis showed that a response around the occipitotemporal region at around 150 ms after visual stimulation was significantly enhanced by within-modal, cross-modal spatial, and intermodal attention. A later response over the right frontal region at around 200 ms was enhanced by within-modal spatial and intermodal attention, but not by cross-modal spatial attention. These effects were estimated to originate from the occipitotemporal and lateral frontal areas, respectively. Thus the results suggest different spatiotemporal dynamics of neural representations of cross-modal attention and intermodal or within-modal attention.

scholarly journals Computational study on the aerodynamics of a long-shrouded contra-rotating rotor in hover

2019 ◽  
Vol 11 ◽  
pp. 175682931983368
Author(s):  
Chao Huo ◽  
Peng Lv ◽  
Anbang Sun
Keyword(s):  
Flow Field ◽  
Opposite Direction ◽  
Computational Study ◽  
Flow Characteristics ◽  
The Other ◽  
Complex Flow ◽  
Sliding Mesh ◽  
Global Performance ◽  
Mesh Method ◽  
Downstream Flow

This paper aims to investigate the aerodynamics including the global performance and flow characteristics of a long-shrouded contra-rotating rotor by developing a full 3D RANS computation. Through validations by current experiments on the same shrouded contra-rotating rotor, the computation using sliding mesh method and the computational zone with an extended nozzle downstream flow field effectively works; the time-averaged solution of the unsteady computation reveals that more uniform flow presents after the downstream rotor, which implies that the rear rotor rotating at opposite direction greatly compensates and reduces the wake; the unsteady computations further explore the flow field throughout the whole system, along the span and around blade tips. Complex flow patterns including the vortices and their interactions are indicated around the blade roots and tips. For further identifying rotor configurations, the rotor–rotor distance and switching two rotor speeds were studied. The computation reveals that setting the second rotor backwards decreases the wake scale but increases its intensity in the downstream nozzle zone. However, for the effect of switching speeds, computations cannot precisely solve the flow when the rear rotor under the windmill because of the upstream rotor rotating much faster than the other one. All the phenomena from computations well implement the experimental observations.

An evaluation of four serum tests for pregnancy.

1983 ◽  
Vol 29 (3) ◽  
pp. 561-563 ◽  
Author(s):  
K W Ryder ◽  
R A Munsick ◽  
T O Oei ◽  
P C Young ◽  
H F Blackford
Keyword(s):  
Positive Result ◽  
Early Pregnancy ◽  
Beta Subunit ◽  
The Other ◽  
Analytical Sensitivity ◽  
Negative Results ◽  
Human Choriogonadotropin ◽  
Beta Hcg

Abstract We evaluated four pregnancy tests (Biocept-G, Beta-CG, Preg/Stat, and HCG-Beta Screen), using sera from 59 nonpregnant subjects and 77 patients with serum human choriogonadotropin beta-subunit (beta-hCG) concentrations ranging from 4 to 100 000 int. units/L. The results obtained for each test were compared with the results predicted on the basis of the sample's beta-hCG concentration and the beta-hCG concentration the manufacturer claimed necessary for a positive result (the test's analytical sensitivity). Biocept-G had the best sensitivity (100%), specificity (98.9%), and accuracy (99.2%). Beta-CG had the poorest sensitivity (86.4%), Preg/Stat the poorest specificity (87.5%), and accuracy (92.6%). We confirmed the manufacturer's claimed analytical sensitivity (200 int. units/L) for the Biocept-G procedure, but our calculated analytical sensitivity for the other tests was significantly different from that claimed by their manufacturers. Best results were obtained with Biocept-G, but with its analytical sensitivity of 200 int. units/L, samples from early pregnancy will give negative results. None of the pregnancy tests evaluated here will establish the presence or absence of early pregnancy with certainty.

INCIDENCE OF HIV-1 AND HIV-2 ANTIBODIES IN HEMOPHILIACS

1987 ◽  
Author(s):  
W Schramm ◽  
L G Gürtler ◽  
H Pohlmann ◽  
I Weigel ◽  
J Eberie ◽  
...  
Keyword(s):  
The Other ◽  
Clotting Factor ◽  
Test Results ◽  
Clotting Factors ◽  
Negative Results ◽  
Group 12 ◽  
Hiv Test ◽  
In The Beginning ◽  
Anti Hiv ◽  
Hiv 1

The presence of antibodies to HIV-1 (anti-HIV-1) was tested in 167 hemophiliacs surveyed and treated at Munich hemophilia center. Increasing numbers of HIV infected patients were observed in the years 1981 to 1986 from 0% to 51,5% (86 positive patients in January 1987 of 167 followed patients). Most of the seroconver-sions occured between 1982 and 1984. The 150 clinically severe affected hemophiliacs (F-VIII-levels up to 5% and need of replacement therapy) showed positive HIV-test results in 55,3% (83 patients) and negative results in 44,7% (67 patients). 5 patients died since 1981, one because of AIDS. 17 patients were not seen since 1984, 14 of those belong to the severly affected group, 12 of them were negative. Since spring 1985 only heat or chemically treated clotting factor preparations are used for substitution. Despite this still 5 seroconversions were observed. Two may be attributed to the use of a preparation heat inactivated in dry state, this preparation is no longer used. The other 3 seroconversions possibly were caused by an occasional use of an noninactivated preparation in the beginning of the change to inactivated clotting factor preparations. 38 of the anti-HIV-1 positive sera were tested for the presence of HIV-2 antibodies also. The methods were ELISA,immunofluorescence and immunoblot. HIV-2 (LAV-2) for these tests was kindly provided by L. Montagnier. Antibodies specific for HIV-2 antigens were not detected, but crossreactions were observed between anti-HIV-1 with HIV-2 antigens particularly epitopes on HIV-2-p27.The data indicate that the use of adequately inactivated clotting factors can prevent infection of hemophilia patients by this route and that HIV-2 was not present in the clotting factor preparations used for the substitution of this group of patients. The incidence of full blown AIDS since 1981 in our group of hemophiliacs is still low (1,2%).

The effect of frontal eye field and superior colliculus lesions on saccadic latencies in the rhesus monkey

1987 ◽  
Vol 57 (4) ◽  
pp. 1033-1049 ◽  
Author(s):  
P. H. Schiller ◽  
J. H. Sandell ◽  
J. H. Maunsell
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Short Latency ◽  
The Other ◽  
Frontal Eye Field ◽  
Express Saccades ◽  
Unimodal Distribution ◽  
Other Hand ◽  
Eye Field ◽  
The Mean

Rhesus monkeys were trained to make saccadic eye movements to visual targets using detection and discrimination paradigms in which they were required to make a saccade either to a solitary stimulus (detection) or to that same stimulus when it appeared simultaneously with several other stimuli (discrimination). The detection paradigm yielded a bimodal distribution of saccadic latencies with the faster mode peaking around 100 ms (express saccades); the introduction of a pause between the termination of the fixation spot and the onset of the target (gap) increased the frequency of express saccades. The discrimination paradigm, on the other hand, yielded only a unimodal distribution of latencies even when a gap was introduced, and there was no evidence for short-latency "express" saccades. In three monkeys either the frontal eye field or the superior colliculus was ablated unilaterally. Frontal eye field ablation had no discernible long-term effects on the distribution of saccadic latencies in either the detection or discrimination tasks. After unilateral collicular ablation, on the other hand, express saccades obtained in the detection paradigm were eliminated for eye movements contralateral to the lesion, leaving only a unimodal distribution of latencies. This deficit persisted throughout testing, which in one monkey continued for 9 mo. Express saccades were not observed again for saccades contralateral to the lesion, and the mean latency of the contralateral saccades was longer than the mean latency of the second peak for the ipsiversive saccades. The latency distribution of saccades ipsiversive to the collicular lesion was unaffected except for a few days after surgery, during which time an increase in the proportion of express saccades was evident. Saccades obtained with the discrimination paradigm yielded a small but reliable increase in saccadic latencies following collicular lesions, without altering the shape of the distribution. Unilateral muscimol injections into the superior colliculus produced results similar to those obtained immediately after collicular lesions: saccades contralateral to the injection site were strongly inhibited and showed increased saccadic latencies. This was accompanied by a decrease of ipsilateral saccadic latencies and an increase in the number of saccades falling into the express range. The results suggest that the superior colliculus is essential for the generation of short-latency (express) saccades and that the frontal eye fields do not play a significant role in shaping the distribution of saccadic latencies in the paradigms used in this study.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Detection of Bovine and Porcine Adenoviruses for Tracing the Source of Fecal Contamination

2004 ◽  
Vol 70 (3) ◽  
pp. 1448-1454 ◽  
Author(s):  
Carlos Maluquer de Motes ◽  
Pilar Clemente-Casares ◽  
Ayalkibet Hundesa ◽  
Margarita Mart�n ◽  
Rosina Girones
Keyword(s):  
Nested Pcr ◽  
Fecal Contamination ◽  
Human Adenovirus ◽  
The Other ◽  
Animal Origin ◽  
Viral Contamination ◽  
Urban Sewage ◽  
Negative Results ◽  
Pcr Assays ◽  
Nested Pcr Assays

ABSTRACT In this study, a molecular procedure for the detection of adenoviruses of animal origin was developed to evaluate the level of excretion of these viruses by swine and cattle and to design a test to facilitate the tracing of specific sources of environmental viral contamination. Two sets of oligonucleotides were designed, one to detect porcine adenoviruses and the other to detect bovine and ovine adenoviruses. The specificity of the assays was assessed in 31 fecal samples and 12 sewage samples that were collected monthly during a 1-year period. The data also provided information on the environmental prevalence of animal adenoviruses. Porcine adenoviruses were detected in 17 of 24 (70%) pools of swine samples studied, with most isolates being closely related to serotype 3. Bovine adenoviruses were present in 6 of 8 (75%) pools studied, with strains belonging to the genera Mastadenovirus and Atadenovirus and being similar to bovine adenoviruses of types 2, 4, and 7. These sets of primers produced negative results in nested PCR assays when human adenovirus controls and urban-sewage samples were tested. Likewise, the sets of primers previously designed for detection of human adenovirus also produced negative results with animal adenoviruses. These results indicate the importance of further studies to evaluate the usefulness of these tests to trace the source of fecal contamination in water and food and for environmental studies.

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