Orienting of Attention

1980 ◽  
Vol 32 (1) ◽  
pp. 3-25 ◽  
Author(s):  
Michael I. Posner

Bartlett viewed thinking as a high level skill exhibiting ballistic properties that he called its “point of no return”. This paper explores one aspect of cognition through the use of a simple model task in which human subjects are asked to commit attention to a position in visual space other than fixation. This instruction is executed by orienting a covert (attentional) mechanism that seems sufficiently time locked to external events that its trajectory can be traced across the visual field in terms of momentary changes in the efficiency of detecting stimuli. A comparison of results obtained with alert monkeys, brain injured and normal human subjects shows the relationship of this covert system to saccadic eye movements and to various brain systems controlling perception and motion. In accordance with Bartlett's insight, the possibility is explored that similar principles apply to orienting of attention toward sensory input and orienting to the semantic structures used in thinking.


2016 ◽  
Vol 37 (3) ◽  
pp. 1095-1107 ◽  
Author(s):  
Jean-Dominique Gallezot ◽  
Beata Planeta ◽  
Nabeel Nabulsi ◽  
Donna Palumbo ◽  
Xiaoxi Li ◽  
...  

Measurements of drug occupancies using positron emission tomography (PET) can be biased if the radioligand concentration exceeds “tracer” levels. Negative bias would also arise in successive PET scans if clearance of the radioligand is slow, resulting in a carryover effect. We developed a method to (1) estimate the in vivo dissociation constant Kd of a radioligand from PET studies displaying a non-tracer carryover (NTCO) effect and (2) correct the NTCO bias in occupancy studies taking into account the plasma concentration of the radioligand and its in vivo Kd. This method was applied in a study of healthy human subjects with the histamine H3 receptor radioligand [11C]GSK189254 to measure the PK-occupancy relationship of the H3 antagonist PF-03654746. From three test/retest studies, [11C]GSK189254 Kd was estimated to be 9.5 ± 5.9 pM. Oral administration of 0.1 to 4 mg of PF-03654746 resulted in occupancy estimates of 71%–97% and 30%–93% at 3 and 24 h post-drug, respectively. NTCO correction adjusted the occupancy estimates by 0%–15%. Analysis of the relationship between corrected occupancies and PF-03654746 plasma levels indicated that PF-03654746 can fully occupy H3 binding sites ( ROmax = 100%), and its IC50 was estimated to be 0.144 ± 0.010 ng/mL. The uncorrected IC50 was 26% higher.



2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S559-S560
Author(s):  
Katherine Kennedy ◽  
John R Bowblis ◽  
Katherine M Abbott

Abstract Stabilizing certified nursing assistant (CNA) employment is necessary for maintaining care networks and providing high quality of care for nursing home (NH) residents. This study’s objective was to examine the relationship of high wages and empowerment practices on CNA retention. We used the 2015 Ohio Biennial Survey to construct a facility-level dataset of 547 NHs and estimated multivariable linear regressions. NHs that provided both high wages and high empowerment were associated with a 12.95 percentage-point improvement in the CNA retention rate (SE = 4.53, t-value = 2.86, p = 0.0045). High wages and a high empowerment score did not have significant effects individually (p > .05). Retention rates were similar between NHs that lacked high wages and scored low on the empowerment scale, and NHs that provided one at a high level but not the other. Implications for better retaining CNAs require multiple empowerment practices combined with high hourly wages.



1946 ◽  
Vol 133 (872) ◽  
pp. 235-248 ◽  

Since a review of the conditions under which siderocytes appear will support a hypothesis that it is an ageing erythrocyte at least as strongly as Grüneberg’s (1941 a ) theory that it should be considered as a young cell, a search was made in blood films of stored mammalian blood and large numbers of siderocytes were found. The conditions affecting the rate of appearance of the siderocytes were studied, and it was found that adverse conditions would hasten their appearance. The relationship of the siderotic material to the 'easily split’ blood iron was also considered, and it seems probable that both are derived from a special and identical fraction of ‘haemoglobin’, and that this phenomenon is related to an intracorpuscular bile pigment formation. The occurrence of siderocytosis after the ingestion of acetyl phenylhydrazine by a ‘normal’ human being was followed, and a close correlation between siderocytosis, erythrocyte destruction and urinary siderosis as described by Peyton Rous (1918) is shown. The siderocyte extrudes its siderotic granules and reverts to a state at present morphologically indistinguishable from the normal erythrocyte, but appears to be susceptible of phagocytosis at this stage. The application of siderocyte counts to clinical medicine is suggested.



1977 ◽  
Vol 128 (3) ◽  
pp. 272-278 ◽  
Author(s):  
Laurence I. Burd ◽  
Melvin Dorin ◽  
Vimala Philipose ◽  
James A. Lemons


2000 ◽  
Vol 6 (7) ◽  
pp. 781-788 ◽  
Author(s):  
JENNIFER SALTZMAN ◽  
ESTHER STRAUSS ◽  
MICHAEL HUNTER ◽  
SARAH ARCHIBALD

Although the majority of research in theory of mind (TOM) has focused on young children or individuals with autism, recent investigations have begun to look at TOM throughout the lifespan and in other neurological and psychiatric populations. Some have suggested that TOM may represent a dissociable, modular brain system that is related to, but separable, from other brain functions including executive functions (EF). Recently, studies have shown that TOM performance can be compromised following an acquired brain insult (e.g, damage to the right hemisphere). However, the relationship of such impaired TOM performance to other brain functions in these cases has not been explored. This study investigated the effects of both normal human aging and Parkinson's disease on TOM. The relationship of TOM performance and EF in these groups was also examined. The results suggested that although TOM performance appeared compromised in the group of individuals with Parkinson's disease, the elderly control participants were relatively unimpaired relative to younger individuals. Significant relationships between several measures of TOM and EF were also found. The implications of these findings, and also the finding that failure on one measure of TOM did not necessarily predict failure on all measures of TOM, are discussed. (JINS, 2000, 6, 781–788.)



2021 ◽  
Vol 1 (25) ◽  
pp. 140-149
Author(s):  
G.G. Parkhomenko ◽  
◽  
S.I. Kambulov ◽  
I.V. Bozhko ◽  
◽  
...  

Choosing rational design parameters of the coupling device for multi-section aggregation of seeders, it is possible to ensure full loading of the power unit while maintaining quality indicators of the technological process at a sufficiently high level. Foreign aggregates are not suitable for use in the Russian Federation due to the different soil and climatic conditions. Purpose of the study: to develop an effective device for multi-section aggregation suitable for domestic modern seeding machines. Subject of the research: the relationship of design parameters and modes of operation of the device for multi-section aggregation of seeders with indicators of the technological process of sowing. A monographic survey of known structures has been carried out, a device for multi-section aggregation of seeding machines has been substantiated by the design and construction method, indicators of the technological process of sowing have been experimentally obtained. The developed coupling device for multi-section aggregation consists of a central frame resting on the wheels and articulated side sections: left and right, which fold when transporting the seeding unit. The total working width of the seeding unit is up to 12.5 meters. According to the research results, the quality of the technological process by the seeding devices meets the regulatory requirements. The instability of the total seeding (0.6–1.1 % for barley and 0.4–0.7 % for wheat) is within the tolerance (up to 3 percent); uneven seeding between devices 3.9–4.2 percent (barley) and 2.6–4.2 percent (wheat) corresponds to the norm (up to 5 percent). The number of seeds embedded at a predetermined depth of the soil corresponds to the required (not less than 80 percent) and was 81.8–83.9 percent for barley and 80.1–83.3 percent for wheat. Not embedded seeds were found in the soil.



HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1036D-1037
Author(s):  
Zhanao Deng ◽  
Jinguo Hu ◽  
Fahrettin Goktepe ◽  
Brady A. Vick ◽  
Brent K. Harbaugh

Cultivated caladiums are valued for their bright colorful leaves and are widely used in containers and landscapes. More than 1500 named cultivars have been introduced during the past 150 years, yet currently only about 100 cultivars are in commercial propagation in Florida. Caladium tubers produced in Florida account for 95% of the world supplies. Loss of caladium germplasm or genetic diversity has been a concern to future improvement of this plant. In addition, the relationship among the available cultivars, particularly those of close resemblance, has been lacking. This study was conducted to assess the genetic variability and relationship in commercial cultivars and species accessions. Fifty-seven major cultivars and 15 caladium species accessions were analyzed using the target region amplification polymorphism marker technique. This marker system does not involve DNA restriction or adaptor linking, but shares the same high throughput and reliability with the amplified fragment length polymorphism system (AFLP). Eight primer combinations amplified 379 scorable DNA fragments among the caladium samples. A high level of polymorphism was detected among the species accessions as well as among cultivars. These markers allowed differentiation of all the cultivars tested, including those hardly distinguishable morphologically. Clustering analysis based on these DNA fingerprints separated the cultivars into five clusters and Caladium lindenii far from other caladium species. The availability of this information will be very valuable for identifying and maintaining the core germplasm resources and will aid in selecting breeding parents for further improvement.



1979 ◽  
Vol 32 (3) ◽  
pp. 317 ◽  
Author(s):  
Patricia A Wilson ◽  
BF Short

The relationship of wool growth to cell proliferation in the follicle bulb and to the subsequent migration and growth of the fibre cortical cells was investigated in 10 Peppin Merino sheep. These sheep had been maintained on a low, medium or high level of nutrient intake to ensure a wide range in wool growth. The number and mitotic activity of the germinal cells in the follicle bulb were determined after administration of colchicine. Cortical cell size was measured following isolation of the fibre cells by acid-treatment of wool.



Author(s):  
Jo Ann Starkweather Bigbee ◽  
Deborah H. Stevenson

The critical nature of information flow as a precursor to project success has been affirmed by both scholars and project management professionals. The data analyzed in this study represent the perceptions of 91 IT project professionals regarding the importance of 18 different aspects of project communication to project success. The relationship of these data vis-a-vis project manager demographics and project/organizational characteristics is explored. Despite a relatively high level of agreement across the respondents regarding which communications are perceived critical to project success, there are clear project and stakeholder circumstances that warrant consideration. The data reveal both statistical and practical dimensions of communication that attribute importance to project success differently for internal as compared to external communication. Furthermore, the emergence of average project duration as a consistently strong correlate of perceived importance of communication to project success is an area of research deserving greater attention.



1989 ◽  
Vol 66 (5) ◽  
pp. 2358-2363 ◽  
Author(s):  
D. J. Israel ◽  
R. S. Pozos

The electromyograms (EMG) of shivering human subjects exposed to 0 degrees C air in an environmental chamber were analyzed to detect slow-amplitude modulations (SAMs, less than 1 Hz) in the EMGs of widely separated muscles and to study the relationship of these SAMs to respiration rate and skin temperature. Distinct amplitude modulations were observed in the raw EMGs during shivering. The peaks in EMG activity occurred simultaneously in the majority of the monitored muscles in all subjects. Pearson correlations between the average rectified EMGs of 93% of the muscles were significant (P less than 0.05). Visual analysis of the EMG and respiration signals indicated that the peaks in muscular activity occurred 6–12 times/min, whereas respiration ranged from 10 to 23 cycles/min. For all subjects respiration was at a higher frequency than amplitude modulation in the EMG. Comparison of EMG records with expiratory flow rate traces in shivering subjects indicated no one-to-one correlation between the occurrence of respiration and EMG amplitude modulations. Respiratory flow rate and average rectified EMG showed significant correlation in only 33% of the cases. In addition, skin temperature changes could not be correlated with the SAMS.



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