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J F Allen

Publications and source records attributed to J F Allen.

52 records · Page 3Linked to original sources
PubMed1988

Black-white earnings ratios: the role of cohort size effects.

"While black-white earning ratios have been rising over time across cohorts [in the United States] there is some evidence that they have been dropping over time within cohorts of recent entrants to the labor market. This has coincided with the entry of the large baby boom cohorts into the labor market. This paper examines the role of race differences in cohort size effects on black-white earnings ratios for male high school graduates using Current Population Survey data. In larger cohorts, the black-white earnings ratio is lower at entry and falls as the cohort progresses through the career, consistent with recent evidence."

Black or African American↗
PubMed1986

Amino acid composition of the 9 kDa phosphoprotein of pea thylakoids.

The 9 kDa phosphoprotein of pea thylakoids was isolated by electroelution from SDS-polyacrylamide gels and its amino acid composition determined. The result is at variance with the amino acid compositions predicted from published nucleotide sequences of the genes for apocytochrome b-559 and for CFo subunit III. The amino acid composition of the 9 kDa phosphoprotein resembles that of the 25 kDa light-harvesting chlorophyll a/b protein (LHC-II). We propose that the 9 kDa polypeptide is a chlorophyll-binding protein of photosystem II, that it functions as a link in excitation energy transfer between LHC-II and the reaction centre, and that its phosphorylation regulates excitation energy distribution by means of mutual electrostatic repulsion between itself and phosphorylated LHC-II.

Amino Acids↗
PubMed1979

A pilot study on left ventricular dimensions and wall stress before and after submaximal exercise.

Left ventricle dimensions and wall stress were measured echocardiographically before and immediately after exercise in 14 athletes and 7 control subjects. Our findings suggest that afterload is an important determinant of cardiac performance and wall hypertrophy in athletes. In spite of major changes in heart rate and blood pressure, left ventricular wall stress remains unchanged following submaximal exercise, in trained and untrained hearts. It would appear that the changes in heart size during exercise are to a large extent limited in untrained ventricles, as smaller left ventricular dimensions are required, to "normalise" wall stress. This results in a lower stroke volume for a given stroke dimensional change. Consequently cardiac output is a function of heart rate rather than stroke volume in untrained subjects. The effect of increased muscle mass in athletes, is to permit larger left ventricular dimensions for a given afterload, thus stroke volume can be augmented. The increase h/R ratio suggests that afterload is more important than preload in the development of left ventricular hypertrophy in rowers and swimmers.

Adolescent↗
PubMed1978

Effects of inhibitors of catalase on photosynthesis and on catalase activity in unwashed preparations of intact chloroplasts.

The catalase activity of unwashed preparations containing intact spinach (Spinacia oleracea L.) chloroplasts is inhibited both by cyanide and by azide at concentrations which also cause inhibition of photosynthetic CO(2)- dependent O(2) evolution.Aminotriazole can also be used to inhibit this contaminant catalase, and in this case inhibition of catalase can be achieved at aminotriazole concentrations which have little effect on the rate of photosynthetic CO(2) fixation. Aminotriazole may be used as a specific inhibitor of catalase in order to demonstrate inhibition of photosynthesis by added H(2)O(2).It is therefore concluded that inhibition of photosynthesis by cyanide and azide does not necessarily result from inhibition of catalase in the chloroplast preparation, and that intact chloroplasts do not produce inhibitory concentrations of H(2)O(2) under the best experimental conditions for CO(2) fixation.

Journal Article↗
PubMed1977

Toxoplasmosis in a California sea lion (Zalophus californianus).

Disseminated toxoplasmosis was diagnosed in a female California sea lion that had been used in thermoregulation studies for about 4 years while housed in a small enclosure with a fresh-water pool at the University of Hawaii, Honolulu. Toxoplasma gondii was demonstrated in and around necrotic lesions of the heart and the stomach. Source of the infection was not established; however, studies on toxoplasmosis in cats were being conducted at the institution, and common caretakers attended both groups of animals.

Animals↗
PubMedDate not supplied

Protein phosphorylation and control of excitation energy transfer in photosynthetic purple bacteria and cyanobacteria.

The function of phosphorylation of light-harvesting polypeptides is well characterised in chloroplasts of green plants, but the prokaryotic cyanobacteria and purple photosynthetic bacteria have quite different light-harvesting polypeptides whose structure and function cannot be controlled in precisely the same way. Nevertheless, cyanobacteria show light-dependent phosphorylation of membrane polypeptides associated with photosystem II and with the light-harvesting phycobilisome, and purple bacteria show light-dependent phosphorylation of low molecular-weight chromatophore membrane polypeptides. In both cases membrane protein phosphorylation is associated with functional changes observed by chlorophyll fluorescence spectroscopy or chlorophyll fluorescence induction kinetics. Here we report on our recent protein sequence and other data concerning the identities of these phosphoproteins. We also discuss the significance of these findings for regulation by protein phosphorylation of photosynthesis in prokaryotes.

Cyanobacteria↗