Showing papers by "Michigan State University published in 1968"
TL;DR: In this paper, a Monte Carlo experiment is carried out to examine the small sample properties of five alternative estimators of a set of linear regression equations with mutually correlated disturbances, and the results show that three of the five estimation methods lead to identical estimates for any sample size, that in many cases the two-stage Aitken estimator performs as well as or better than the other estimators, and most of the asymptotic properties of this estimator tend to hold in small samples as well.
Abstract: A Monte Carlo experiment is carried out to examine the small sample properties of five alternative estimators of a set of linear regression equations with mutually correlated disturbances. The estimators considered are ordinary least squares, Zellner's two-stage Aitken, Zellner's iterative Aitken, Telser's iterative, and maximum likelihood. The experiment, based on 100 samples, provides approximate sampling distributions for samples of size 10, 20 and 100 for various model specifications. The results show that three of the five estimation methods lead to identical estimates for any sample size, that in many cases the two-stage Aitken estimator performs as well as or better than the other estimators, and that most of the asymptotic properties of this estimator tend to hold in small samples as well.
465 citations
354 citations
329 citations
TL;DR: Up to 55% of the activity for these enzymes in spinach leaves have been found in the particulate fractions after the initial centrifugation, suggesting the leaf peroxisomes are probably the site of oxygen uptake during photorespiration.
303 citations
TL;DR: The low-lying even-parity energy levels and wave functions of the even isotopes of tungsten, osmium and platinum are calculated within the framework of Bohr's collective Hamiltonian as mentioned in this paper.
240 citations
TL;DR: In this article, the pairing-plus-quadrupole matrix elements are compared with those of more realistic interactions, and it is decided to keep only matrix elements between states of two adjacent oscillator shells.
223 citations
01 Jan 1968
194 citations
TL;DR: Results are presented which are interpreted as indicating the existence of four pools of particulate hexokinase activity in rat brain, defined by their susceptibility to exposure and solubilization by ATP, glucose-6-P, and Triton X-100.
191 citations
TL;DR: Radioactive carbon assimilated by vegetative cells of Anabaena cylindrica in the light passed via an intrafilamentous route into heterocysts in the dark and after several hours, label per heterocyst approximated label per vegetative cell.
Abstract: Radioactive carbon assimilated by vegetative cells of Anabaena cylindrica in the light passed via an intrafilamentous route into heterocysts in the dark. After several hours, label per heterocyst approximated label per vegetative cell. Much of the label entering heterocysts was not available for diffusional exchange back into vegetative cells.
168 citations
TL;DR: It is concluded that normal ripening of pome fruits is a highly coordinated process of biochemical differentiation involving directed protein synthesis.
Abstract: Protein synthesis by intact Bartlett pear fruits was studied with ripening as measured by flesh softening, chlorophyll degradation, respiration, ethylene synthesis, and malic enzyme activity. Protein synthesis is required for normal ripening, and the proteins synthesized early in the ripening process are, in fact, enzymes required for ripening. (14)C-Phenylalanine is differentially incorporated into fruit proteins separated by acrylamide gel electrophoresis of pome fruits taken at successive ripening stages. Capacity for malic enzyme synthesis increases during the early stage of ripening. Fruit ripening and ethylene synthesis are inhibited when protein synthesis is blocked by treatment with cycloheximide at the early-climacteric stage. Cycloheximide became less effective as the climacteric developed. Ethylene did not overcome inhibition of ripening by cycloheximide. The respiratory climacteric is not inhibited by cycloheximide. It is concluded that normal ripening of pome fruits is a highly coordinated process of biochemical differentiation involving directed protein synthesis.
168 citations
TL;DR: In this article, the authors assign conformations and configurations to oximes of several aldehydes and ketones from analysis of their 60-Mc NMR spectra using spin-spin coupling data from the cis isomers (hydroxy cis to hydrogen) of the aldoximes in terms of rotamers I and II.
TL;DR: In this paper, a family of methods for calculating the surface heat flux from the transient temperature history measured at an interior position in a heat-conducting solid possessing constant thermal properties is presented.
TL;DR: The relatively greater decrease in ammonia nitrogen excretion over total ammonia excretion in fish exposed to the higher concentrations of ammonia suggests that excretion of other nitrogenous compounds occured to partially compensate for the significant decrease in nitrogen excreted by these fish.
TL;DR: The weight loss was the best index of withdrawal; it was dose-dependent and could be quantified, and the increase in brain NE after morphine is peculiar to this drug and is not a characteristic of the drug class.
TL;DR: The lineage of the cell groups which contribute to the tissues of the adult ovary has been determined and the importance in morphogenesis of acellular membranes secreted at the interface separting cells of different prospective meanings is stressed.
Abstract: Light and electron microscopical studies allow a descriptive account to be given of the preadult development of the ovary of Drosophila melanogaster. The lineage of the cell groups which contribute to the tissues of the adult ovary has been determined. The earliest morphologically detectable event in the differeentiation of each ovariole is the formation during the larval period of its terminal filament. Oogonia play no role in the induction of terminal filaments. The developmental events which transform a spherical mass of ovarian cells into a collection of multicellular cylinders is described. The importance in morphogenesis of acellular membranes secreted at the interface separting cells of different prospective significances is stressed. Such membranes may serve to regulate the future migration of cell populations or as sites of attachment for monolayers of cells which later fuse to form multinucleated muscle sheaths. The transformation of oogonia to cystoblasts coincides with and presumably depends upon the same hormonal stimulus which causes metamorphosis. The first oocytes to undergo crossing over do so between 24 and 36 hours after puparium formation.
TL;DR: The literature of bimolecular lipid membranes (BLM), including abstracts, has been reviewed through January, 1967 and some recent studies from this and several other laboratories are included.
TL;DR: In this paper, the point arboricity ρ(G) of a graph G is defined as the minimum number of subsets in a partition of the point set of G so that each subset induces an acyclic subgraph.
Abstract: The point-arboricity ρ(G) of a graphG is defined as the minimum number of subsets in a partition of the point set ofG so that each subset induces an acyclic subgraph Dually, the tuleity τ(G) is the maximum number of disjoint, point-induced, non-acyclic subgraphs contained inG Several results concerning these numbers are presented, among which are formulas for the point arboricity and tulgeity of the class of completen-partite graphs
TL;DR: A theory of collective motion based on the time-dependent Hartree-Bogolyubov approximation for the pairing-plus-quadrupole model was proposed in this article.
TL;DR: In this paper, the effects on deformational behavior produced by the addition of sand particles to the ice matrix were studied using axial stress creep tests and constant axial strain-rate tests.
Abstract: The mechanical properties of a saturated frozen sand were studied using constant axial stress creep tests and constant axial strain-rate tests. Observation of the effects on deformational behavior produced by the addition of sand particles to the ice matrix led to an analysis useful in predicting creep rates for a constant stress and stress levels for a constant strain rate. The relationship between strain rate and stress for polycrystalline ice considers a strain dependent hardening term and a strain energy dependent softening term. Parameters of the equation include stress and temperature. Stress factors, dependent on sand volume concentration and friction and dilatancy of the sand, are used in conjunction with the equation for polycrystalline ice to give predictions of the mechanical behavior of the sand-ice system. These are in reasonable agreement with experimental data.
TL;DR: The results support the idea that processes involved in the transport of indoleacetic acid (IAA) are specific for growth-promoting auxins, and a model is discussed in which auxin-binding to the plasma membrane and reversible changes of membrane conformation may provide a basis for active secretion and for the observed cooperativity.
Abstract: Movement of radioactive auxins was analysed in corn coleoptile sections. The results support the idea that processes involved in the transport of indoleacetic acid (IAA) are specific for growth-promoting auxins.
TL;DR: Autoradiographs of protonemata treated with a labeled cytokinin, benzyladenine-benzyl-7-(14)C, show a striking accumulation of the radioactivity in caulonema cells which are in the stage of bud formation, and in the buds themselves.
Abstract: Application of cytokinins to moss protonemata of the proper physiological age causes bud formation on specific cells (caulonema). During the early stages of their development, buds revert to protonemal filaments if the cytokinin has been removed by washing the protonemata. This indicates that the hormone is not acting as a "trigger" but has to be present during a critical period of time until differentiation is stabilized. Autoradiographs of protonemata treated with a labeled cytokinin, benzyladenine-benzyl-7-(14)C, show a striking accumulation of the radioactivity in caulonema cells which are in the stage of bud formation, and in the buds themselves. Cells which did not react to the hormone contained very little radioactivity. The accumulation of benzyladenine in the "target cells" may be due to the presence of binding sites which, in turn, may distinguish responding cells from non-responding ones.
TL;DR: In this article, aldehyde and ketone N,N-dimethyldrazones were assigned configurational and conformations from analyses of their 60-Mc NMR spectra.
TL;DR: The geneticist is able to study mutations which presumably alter the structure of enzymes, resulting in differential electrophoretic mobilities of the molecules, while their catalytic activity is retained.
Abstract: Progress in the biochemical genetics of diploid organisms has been very marked in the last decade. Such progress is almost invariably due to new methods and tools which the scientist utilizes in conjunction with existing methodology to elucidate pertinent questions. Zone electrophoresis in various gel matrices has already proven to be such a powerful new tool in experimental biology. It has been known since the early part of this century, when Garrod put forth the concept of inborn errors of metabolism, that altered enzyme activity may be an expression of genetic variation. The early period of biochemical genetics was confined to studies of enzyme variation due to changes in total catalytic activity of the enzyme investigated. Now, by use of the zone electrophoretic techniques (Smithies, 1955) in conjunction with the highresolution \"zymogram\" method for displaying enzyme activity on gels (Hunter & Markert, 1957), the geneticist is able to study mutations which presumably alter the structure of enzymes, resulting in differential electrophoretic mobilities of the molecules, while their catalytic activity is retained. With the aid of these methods, a large number of electrophoretic variants of enzymes have been discovered (Shaw, 1965). With these findings came the knowledge that enzymes may occur in more than one molecular form. These multiple forms have been designated isozymes (Markert & Moller, 1959). Although a large number of genetic enzyme variations have been described in many organisms (W rbblewski, 1961), the number of genetic isozyme studies in plants has been minimal. The first such study dealt with genetic variations of the esterases in maize endosperm (Schwartz, 1960). Since then, other isozyme systems have been investigated in Zea mays (Scandalios, 1965a). Some of these systems are leucine aminopeptidase (Beckman, et a!., 1964; Scandalios, 1964; 1965b) ; catalase (Scandalios, 1965~) ; amylase (Scandalios, 1966a) ; alcohol dehydrogenase (Scandalios, 1966b; 1967). During the past three years, my efforts have been in part directed a t elucidating the genetic control of the catalase isozymes in maize. This paper summarizes some of the results obtained to date.
TL;DR: Electron transport in chloroplasts can proceed by two pathways and observations suggest that, at high light intensities and in the absence of amine uncouplers, the phosphorylating electron transport is superimposed on a constant non-phosphorylates electron transport.
TL;DR: Cells of Azotobacter vinelandii encysted in Burk's nitrogen-free liquid media which had been supplemented with n-butyl alcohol, beta-hydroxybutyrate, or crotonate promoted abortive encystment, which was manifested by the disorganization of the exine and the release of a highly viscous material into the medium.
Abstract: Cells of Azotobacter vinelandii encysted in Burk9s nitrogen-free liquid media which had been supplemented with n -butyl alcohol, β-hydroxybutyrate, or crotonate Butyraldehyde and butyrate did not influence the extent of encystment In the absence of glucose, β-hydroxybutyrate enhanced the rate and extent of encystment In the presence of glucose, it promoted abortive encystment, which was manifested by the disorganization of the exine and the release of a highly viscous material into the medium The soluble, viscous polymer was separated from the medium by a series of ethyl alcohol precipitations and identified as a mucopeptide It was cleaved by treatment with lysozyme and lysostaphin with a concomitant increase in reducing power It contained 139% N; 56% amino acids, as alanine (alanine, lysine, and glutamic acids); and 42% hexosamines The polymer appeared to be similar to a noncross-linked peptidoglycan Images
TL;DR: Observations with black or bilayer lipid membranes formed from photosynthetic pigments such as chlorophylls and xanthophyllS exhibit two interesting photoelectric phenomena: a photovoltaic effect, and photoconductivity.
Abstract: SEVERAL investigators have shown that black or bilayer lipid membranes (BLM) are the most realistic approach to cell membrane models. A review of the relevant literature has recently been published1. This communication reports some observations with such membranes formed from photosynthetic pigments such as chlorophylls and xanthophylls. The BLM in aqueous solution exhibit two interesting photoelectric phenomena: (a) a photovoltaic effect, and (b) photoconductivity.
TL;DR: In this article, a partial characterization of clique graphs is given, including a method for constructing a graph having a given graph as its clique graph, provided the given graph meets certain conditions.