Showing papers by "University of York published in 1972"

Lectures on Macroeconomics

Abstract: Lectures on Macroeconomics provides the first comprehensive description and evaluation of macroeconomic theory in many years. While the authors' perspective is broad, they clearly state their assessment of what is important and what is not as they present the essence of macroeconomic theory today. The main purpose of Lectures on Macroeconomics is to characterize and explain fluctuations in output, unemployment and movement in prices. The most important fact of modern economic history is persistent long term growth, but as the book makes clear, this growth is far from steady. The authors analyze and explore these fluctuations. Topics include consumption and investment; the Overlapping Generations Model; money; multiple equilibria, bubbles, and stability; the role of nominal rigidities; competitive equilibrium business cycles, nominal rigidities and economic fluctuations, goods, labor and credit markets; and monetary and fiscal policy issues. Each of chapters 2 through 9 discusses models appropriate to the topic. Chapter 10 then draws on the previous chapters, asks which models are the workhorses of macroeconomics, and sets the models out in convenient form. A concluding chapter analyzes the goals of economic policy, monetary policy, fiscal policy, and dynamic inconsistency. Written as a text for graduate students with some background in macroeconomics, statistics, and econometrics, Lectures on Macroeconomics also presents topics in a self contained way that makes it a suitable reference for professional economists. Olivier Jean Blanchard and Stanley Fischer are both Professors of Economics at MIT

A Note on Group Rings of Certain Torsion-Free Groups

Abstract: As a step towards characterizing ID-groups (i.e., groups G such that, for every ring R without zero-divisors, the group ring RG has no zero-divisors), Rudin and Schneider defined Ω-groups, a possibly wider class than that of right-orderable groups, and proved that if every non-trivial finitely generated subgroup of a group G has a non-trivial H-group as an epimorphic image, then G is an ID-group. We prove that such groups are even Ω-groups and obtain the analogous result for right-orderable groups.

Amino Acid Biosynthesis by Isolated Chloroplasts during Photosynthesis

Abstract: The pool sizes of the common amino acids in purified intact chloroplasts from Vicia faba L. were measured (nanomoles per milligram chlorophyll). The three amino acids present in the highest concentrations were glutamate, aspartate, and threonine. Alanine, serine, and glycine were each present at levels between 15 and 20 nanomoles per milligram chlorophyll and 13 other amino acids were detectable at levels below 10. Only aspartate, alanine, glycine, serine, threonine, and lysine became labeled during photosynthetic 14 CO 2 fixation by isolated chloroplasts: the label in aspartate represented over 60% of the total 14 C found in the amino acids. Glutamate dehydrogenase, glutamate-oxaloacetate, and glutamate-pyruvate aminotransferases were present in the chloroplasts, but no other transferase activities from glutamate could be detected. The chloroplasts were able to synthesize a total of 17 other protein amino acids from either alanine or aspartate, but no synthesis of leucine by aminotransferase reactions could be detected. The synthesis of aspartate was studied in more detail. The enzyme systems required for the generation of oxaloacetate from triose phosphate were virtually absent from the chloroplasts but present in the leaf cytoplasmic fraction. Addition of either a leaf “cytoplasmic” fraction or an oxaloacetate generating system resulted in an increased proportion of the total 14 C fixed being found in the amino acid fraction during photosynthetic 14 CO 2 fixation. It is suggested that the supply of oxaloacetate from the cytoplasm is one of the important factors controlling the synthesis of amino acids by the chloroplast.

1-anilinonaphthalene-8-sulphonate. The dependence of emission spectra on molecular conformation studied by fluorescence and proton-magnetic resonance.

Abstract: The conformations of 1-anilinonaphthalene-8-sulphonate in 2H2O and C2H3O2H have been determined by proton magnetic resonance spectroscopy, and its fluorescence spectra as a solid, in a methyl-cellulose matrix, and in solution in water, methanol and aqueous MgCl2 have been studied. The aromatic rings of anilinonaphthalene-sulphonate are more nearly coplanar in C2H3O2H than in 2H2O. The NH proton fails to exchange with 2H from the solvent in C2H3O2H, and its chemical shift indicates that there is a strong interaction with the sulphonate group. The solvents in which rapid exchange of the NH proton occurs are those in which the quantum yield of fluorescence of anilinonaphthalene-sulphonate is quenched. The fluorescence emission is enhanced and blue-shifted in strong aqueous MgCl2 solutions. Under some conditions the overall emission is composed of contributions from two separable spectra. It is argued that an efficient mechanism for quenching the first excited singlet of anilinonaphthalene-sulphonate is through vibrations of bonds to the nitrogen, and that the shifts of emission maxima in non-aqueous solvents may be partly a result of the molecule displaying different spectra in different conformations (rather than simply a solvent-polarity-induced change). There is no convincing reason for the assumption that when a fluorescence enhancement follows the binding of anilinonaphthalene-sulphonate to a biological structure the site of interaction must be hydrophobic.

Uptake and binding of uranyl ions by barley roots.

Abstract: After undergoing the processing for electron microscopy, bound uranyl ions are revealed as characteristic electron-opaque crystals. Meristematic walls and associated vesicles become heavily labeled, while pinocytotic accumulation into vacuoles seems probable in cap cells and those just behind the meristem. The endodermal Casparian strip and suberinized lamella are effective barriers to the passage of uranyl ions.

Significance of Molecular Alignment and Orbital Steering in Mechanisms for Enzymatic Catalysis

Abstract: Calculations of the energy required to form misaligned transition states in the confines of a solvent cage indicate that many reactions could be very considerably catalysed by precise alignment (orbital steering) in enzyme active sites.

Vocal rehabilitation of laryngectomees:Preliminary report of a new technic

Abstract: A modified cervical esophagostomy was used to restore speech to eight laryngectomees who were unable to develop an esophageal voice. This was accomplished by connecting either a specially designed reed larynx or a valved external bypass between the tracheostoma and esophagostomy opening. The feasibility of this approach has been demonstrated by this pilot study, but more experience is necessary before it is certain that patients will tolerate the inconvenience of an external device and a permanent esophageal fistula.

Effects of plant hormones on the stomata of barley: A study of the interaction between abscisic acid and kinetin.

Abstract: It is known that kinetin and abscisic acid affect stomatal aperture. A statistically significant interaction between kinetin and abscisic acid at concentrations of abscisic acid between 10-5 and 10-6M is demonstrated for barley. It is suggested from this and other work that the results obtained may only be true for graminaceous species and not for other monocotyledons or for dicotyledons.

Mechanisms of Mammalian Hydroxylation: Some Novel Metabolites of Chlorobenzene

Abstract: 1. The urinary metabolites of [14C]chlorobenzene administered orally to rabbits have been examined.2. The identified metabolites which account for 98-8% of the radioactivity in the urine include four previously unreported metabolites, namely, quinol, 3-chlorocatechol and o- and m-chlorophenylmercapturic acids.3. The distribution of isomeric mercapturic acids, free phenols and phenolic conjugates is reported.4. The major metabolites are r-chlorophenylmercapturic acid and the conjugates of 4-chlorocatechol.5. The metabolism of chlorobenzene is discussed in terms of an initial epoxidation to 3,4-chlorobenzene oxide.

Experiments On Mimicry: Ii. the Effect of a Batesian Mimic On Its Model

Abstract: Artificial prey, consisting of pieces of pastry placed on coloured cards, were placed on a lawn ; birds, predominantly Blue Tits, were allowed to eat them. When the prey were palatable, the birds ate more from black cards than from red, blue or grey cards. The birds ate significantly more of a "perfect" Batesian mimic than of its model, placed on an identical card, but made distasteful by soaking in a 2 1/2% solution of quinine dihydrochloride. This "discrimination" by the birds probably shows that they can see a slight yellowness in the quinine-soaked pastry. The birds showed no preference between blue, red and yellow prey when the pastry was palatable, but ate significantly more pastry from blue than from red cards when the pastry was distasteful. As this happened equally when the blue or the red prey were in the greater number, it was not due to Mullerian mimicry in the context of the experiment, but probably resulted from Batesian mimicry between the blue distasteful prey and the grey palatable prey which was intended as a control in the experiment. Thus the blue prey, acting as a Batesian model, is shown to suffer increased predation as a result of the predators' confusing it with its mimic.

Breast cancer and associated extramammary malignant neoplasms.

Abstract: The phenomenon of multiple primary malignant neoplasms has interested students of oncology for many years. Since the report of Billroth [I] appeared in 1870 numerous compilations of multiple primary malignant tumors have been made [2-41. Few investigators, however, have dealt specifically with the association of breast cancer, either unilateral or bilateral, and extramammary malignant neoplasms. Recently Schoenberg, Greenberg, and Eisenberg [5] reported an excess of at least 50 per cent observed over expected second primary lesions when the initial primary tumor was in the breast and the second primary tumor was in either the digestive system or the genital organs. Further, Schottenfeld and Berg [6] have concluded that there is an increased risk for patients ‘with ovarian and endometrial cancer to incur metachronous cancer of the breast. Inasmuch as breast cancer is one of the most prevalent malignant neoplasms in women, I thought that a study of its association with extramammary malignant neoplasia might contribute to the understanding of some aspects of breast cancer. It would be of interest to determine what patterns emerge and the effect of subsequent neoplasms on prognosis and longevity; also to correlate the menstrual patterns, blood groups, and familial history of neoplasia with breast and nonmammary malignant tumors.

Archaeological and historical evidence for subsidence in southern Britain

Abstract: This paper is presented as a warning of the pitfalls which are involved in a too ready and uncritical acceptance of the evidence for apparent changes in relative land and sea level which has been derived from the archaeological and historical remains around the coasts of southern Britain. The general trends of relative sea level changes in the later Holocene are indicated; but I am concerned more to correct some of the misapprehensions and inexact conclusions which have been drawn from the often imprecise data, and to establish a wider recognition of the types of errors and inaccurate assumptions which have been promulgated in some publications, and which erroneously, albeit unwittingly, have been cited by specialists in other disciplines to reinforce or to substantiate conclusions derived from their different data. The optimum conditions for establishing the former positions of relative mean sea level are found in deposits which can be shown to have formed in a known relationship to sea level as part of a continuous halosere from marine sands and clays to freshwater fen deposits (cf. Churchill I965, p. 240). I would stress that estimates of sea level changes should be based primarily on the analysis of physiographical data; the archaeological and historical data may provide complementary and corroborative evidence of relative land and sea level changes, but they are generally too imprecise to stand alone as definitive indicators of actual mean sea level or tidal heights.

The Hull family survey. II. Family planning in the first 5 years of marriage.

Abstract: Of 350 couples married in Hull in 1965-66 and interviewed shortly after marriage for their views on family size and birth spacing 312 were available for reinterview to compare initial intentions with fertility experience during the first 5 years of marriage (1970-71). There was a downward revision in intended family size (2.61 children first interview 2.23 reinterview) and a dissappearance of correlates of differences in fertility intention (occupation length of education of husband diminished effect of religion). Upward revaluations were due primarily to unintentional over-achievement. Birth intervals were shorter than intended. 93% had used contraceptives; 52.8% before first pregnancy 75.4% before second. 3 contraceptive methods were employed: condom (59%) pill (48%) and withdrawal (41%). Social profiles of users of the various contraceptives were outlined. 2/3 of the pregnancies were planned. Results demonstrate that family planning attitudes and actual behavior can be viewed as rational except in the area of risk taking by a large number of contraceptive users a part that requires more study.

A class of unitary block designs

Abstract: A unital is a 2 ( q 3 + l , q + l , 1) design. Apart from the unitals associated with the unitary polarities of desarguesian planes of order q2, there is one other known family, namely those of Ree type, discovered by Liineburg [4]. Both of these families have doubly-transitive automorphism groups, and the two families are known to be distinct (see O'Nan [5]). In [2], the following result was proved:

The effect of iodination of particular tyrosine residues on the hormonal activity of insulin.

Abstract: Insulin dissolved in aqueous or methanolic buffer was iodinated to give preparations containing an average of between one and five iodine atoms per insulin monomer. The resultant preparations were fragmented in various ways and the ratio of tyrosine to monoiodotyrosine and di-iodotyrosine was determined in each fragment. This has allowed the distribution of iodine between the combined A-chain tyrosine residues and the individual B-chain tyrosine residues to be determined. The hormonal activity of each of these iodinated insulin preparations was measured from their effect on the production of 14CO2 from [1-14C]glucose by isolated adipose cells. The results were interpreted as meaning that the iodination of tyrosine residue A19 or B16 leads to the inactivation of insulin. Speculations are made about the nature of an interaction between insulin and a receptor site on the target tissue.