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J Eccles

Publications and source records attributed to J Eccles.

At least 19 recordsLinked to original sources

Do self-fulfilling prophecies accumulate, dissipate, or remain stable over time?

The authors examined whether self-fulfilling prophecies accumulate, dissipate, or remain stable over time by using data from more than 500 6th- through 12th-grade students in public school math classes. The authors used multiple regression analyses to assess the extent to which teacher perceptions predicted students' final math marks and standardized math-test scores from 6th through 12th grade. Control variables included 5 measures of student motivation and 2 measures of previous achievement. The results were consistent with both the dissipation and stability hypotheses. Implications for understanding the extent to which social perception creates social reality and the role of expectations in social problems are discussed.

Achievement↗

In search of the powerful self-fulfilling prophecy.

This research examined moderators of naturally occurring self-fulfilling prophecies. The authors assessed whether positive or negative self-fulfilling prophecies were more powerful and whether some targets were more susceptible to self-fulfilling prophecies because of their self-concepts in a particular achievement domain and previous academic records. Participants were 98 teachers and 1,539 students in sixth-grade public school math classes. Results yielded a strong pattern showing that teacher perceptions predicted achievement more strongly for low achievers than for high achievers. Results also yielded a much weaker pattern showing that teacher overestimates predicted achievement more strongly than teacher underestimates. Implications for social perceptual accuracy, self-enhancement theory, and understanding when self-fulfilling prophecies are stronger are discussed.

Achievement↗

Age and gender differences in children's self- and task perceptions during elementary school.

We examined the development of children's self- and task perceptions during the elementary school years. 865 first-, second,- and fourth-grade children (ages 7-10) completed questionnaires assessing their perceptions of competence in, and valuing of, activities in several activity domains (math, reading, sports, and instrumental music). Factor analyses showed that even the first graders had differentiated self-beliefs for the various activities. These analyses also indicated that children's competence beliefs and subjective task values formed distinct factors. Analyses assessing age and gender differences in children's beliefs showed that for all the activities except sports, younger children's (particularly the first graders) perceptions of competence and subjective task values were more positive than the beliefs of the older children. Boys had more positive competence beliefs and values than did girls for sport activities, and more positive competence beliefs for mathematics. Girls had more positive competence beliefs and values than did boys for reading and music activities.

Achievement↗

The application of SSADM to modelling the logical structure of proteins.

A logical design that describes the overall structure of proteins, together with a more detailed design describing secondary and some supersecondary structures, has been constructed using the computer-aided software engineering (CASE) tool, Auto-mate. Auto-mate embodies the philosophy of the Structured Systems Analysis and Design Method (SSADM) which enables the logical design of computer systems. Our design will facilitate the building of large information systems, such as databases and knowledgebases in the field of protein structure, by the derivation of system requirements from our logical model prior to producing the final physical system. In addition, the study has highlighted the ease of employing SSADM as a formalism in which to conduct the transferral of concepts from an expert into a design for a knowledge-based system that can be implemented on a computer (the knowledge-engineering exercise). It has been demonstrated how SSADM techniques may be extended for the purpose of modelling the constituent Prolog rules. This facilitates the integration of the logical system design model with the derived knowledge-based system.

Amino Acid Sequence↗

A unitary hypothesis of mind-brain interaction in the cerebral cortex.

A brief introduction to the brain-mind problem leads on to a survey of the neuronal structure of the cerebral cortex. It is proposed that the basic receptive units are the bundles or clusters of apical dendrites of the pyramidal cells of laminae V and III-II as described by Fleischhauer and Peters and their associates. There are up to 100 apical dendrites in these receptive units, named dendrons. Each dendron would have an input of up to 100,000 spine synapses. There are about 40 million dendrons in the human cerebral cortex. A study of the influence of mental events on the brain leads to the hypothesis that all mental events, the whole of the World 2 of Popper, are composed of mental units, each carrying its own characteristic mental experience. It is further proposed that each mental unit, named psychon, is uniquely linked to a dendron. So the mind-brain problem reduces to the interaction between a dendron and its psychon for all the 40 million linked units. In my 1986 paper (Proc. R. Soc. Lond. B 227, 411-428) on the mind-brain problem, there was developed the concept that the operation of the synaptic microsites involved displacement of particles so small that they were within range of the uncertainty principle of Heisenberg. The psychon-dendron interaction provides a much improved basis for effective selection by a process analogous to a quantal probability field. In the fully developed hypothesis psychons act on dendrons in the whole world of conscious experiences and dendrons act on psychons in all perceptions and memories. It is shown how these interactions involve no violation of the conservation laws. There are great potentialities of these unitary concepts, for example as an explanation of the global nature of a visual experience from moment to moment. It would seem that there can be psychons not linked to dendrons, but only to other psychons, creating what we may call a psychon world.

Animals↗

The pattern of childhood hepatitis B infection in two Gambian villages.

Serologic markers of hepatitis B virus (HBV) infection were measured in children from Manduar and Keneba, two adjacent villages in The Gambia, in 1980 and in 1984. The rate of HBV infection over the 4 years differed markedly: in Manduar 71% of children who were less than 5 years of age in 1980 became infected, whereas in Keneba only 37% became infected. Male children were more frequent carriers of either HBs or e antigen than were female children. Marked clustering of hepatitis B surface antigen (HBsAg) antigenemia within sibling relationships was shown in both villages. The chance of the youngest child in a household being a carrier of HBsAg was strongly related to the number of antigen-positive siblings. Four years later, 53% of children who were initially positive for HBsAg and 33% who were positive for hepatitis B e antigen still carried these antigens. Jaundice was not observed.

Adolescent↗

A theoretical analysis of the effects of sonication on differential absorption flattening in suspensions of membrane sheets.

A theoretical analysis is presented for the flattening of absorption and circular dichroic spectra of suspensions of membrane sheets containing proteins. Equations are presented to describe the dependence of this artifact on the size of the sheets. Values for the flattening coefficients QA and QB are calculated both as a function of absorptivity and sheet size. These studies show that sonication in an inadequate procedure for eliminating flattening in these samples.

Mathematics↗

Charged amino acids as spectroscopic determinants for chlorophyll in vivo.

In this paper we propose that the large spectroscopic red shifts observed for chlorophyll (Chl) and bacteriochlorophyll (BChl) in vivo may be due to charged amino acids in the binding site. Molecular orbital calculations of the transition energies of Chl in the field of external charges are carried out. The calculated wavelength shifts induced by these charges are comparable in magnitude to those observed in vivo. Moreover the size of the shifts increases in the order BChl b > BChl a > Chl a, which is the observed trend. The ability of the calculations to account for both the absolute and relative magnitudes of the wavelength shifts argues for the validity of the model. Further indirect support comes from the recent demonstration that charged amino acids are responsible for the colors of visual pigments and bacteriorhodopsin. In addition to their effects on spectra the presence of external charges induces large changes in the ionization potential of Chl molecules and thus might explain the in vivo alteration of the oxidation potentials in reaction centers.

Journal Article↗

Sir Karl Popper.

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Austria↗