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Showing papers by "Michigan State University published in 1985"


Journal ArticleDOI
TL;DR: Factors such as pH and chelation govern the reactivity of the transition metals with dioxygen and "oxy-radicals" and therefore influence the apparent mechanisms by which oxidative damage to phospholipids, DNA, and other biomolecules is initiated.

1,133 citations


Journal ArticleDOI
21 Jun 1985-Science
TL;DR: Model studies suggest that the ability of Phanerochaete chrysosporium to metabolize these compounds is dependent on the extracellular lignin-degrading enzyme system of this fungus.
Abstract: The white rot fungus Phanerochaete chrysosporium degraded DDT [1,1,-bis(4-chlorophenyl)-2,2,2-trichloroethane], 3,4,3',4'-tetrachlorobiphenyl, 2,4,5,2',-4',5'-hexachlorobiphenyl, 2,3,7,8-tetrachlorodibenzo-p-dioxin, lindane (1,2,3,4,5,6-hexachlorocylohexane), and benzo[a]pyrene to carbon dioxide. Model studies, based on the use of DDT, suggest that the ability of Phanerochaete chrysosporium to metabolize these compounds is dependent on the extracellular lignin-degrading enzyme system of this fungus.

910 citations


Journal ArticleDOI
TL;DR: In this paper, meta-analytiques sont utilisé for determiner statistiquement la relation existant entre les caracteristiques du travail and la satisfaction vis-a-vis du trawail, en prenant en compte la force du besoin de developpement personnel de l'employe
Abstract: Des procedes meta-analytiques sont utilises pour determiner statistiquement la relation existant entre les caracteristiques du travail et la satisfaction vis-a-vis du travail, en prenant en compte la force du besoin de developpement personnel de l'employe

717 citations


Journal ArticleDOI
TL;DR: Five diagnostic procedures are reviewed: partial regression plots, the “hat” matrix, studentized residuals, DFITSi, and DFBETASij, to underscore the point that the diagnostics cannot be employed mechanically.
Abstract: Gauging the robustness of regression estimates is especially important in small-sample analyses. Here, we examine recent developments in the detection and analysis of outliers and influential cases...

689 citations


Journal ArticleDOI
TL;DR: The authors summarizes the literature on frontier production and cost functions and their relationship to the problem of efficiency measurement, and summarizes a survey of frontier production methods and their relationships to the efficiency measurement problem.
Abstract: This paper summarizes the literature on frontier production and cost functions and on their relationship to the problem of efficiency measurement.

674 citations


Journal ArticleDOI
TL;DR: An oxygen microelectrode was modified to measure O concentrations in wet aggregates of silt loam soil as mentioned in this paper, which can be made in as little as 0.1mm increments to a depth of 12 mm.
Abstract: An oxygen microelectrode was modified to measure O concentrations in wet aggregates of a silt loam soil. The microelectrode tip had an O-permeable membrane opening 3 µm in diameter, and O measurements could be made in as little as 0.1-mm increments to a depth of 12 mm. When aggregates were incubated in air, steep O gradients usually occurred over very small distances from the aggregate surface. The smallest aggregate exhibiting an anaerobic center had a radius of 4 mm, although small aggregates (radius ≤ 6 mm) were generally oxic. Larger aggregates (radius ≥ 10 mm) often had measureable anaerobic centers, with the exception of those from a native prairie soil which exhibited irregular O profiles and had aerobic centers, apparently due to O intrusion caused by old root channels. Oxygen profiles obtained in 45 degree increments around an aggregate circumference were used to construct contour maps of O concentrations within the aggregate. Oxygen gradients were somewhat asymmetric, suggesting nonuniformly distributed sites of O consumption. An average intra-aggregate O diffusion coefficient of 8.5 × 10 cm · s was measured for water-saturated aggregates. The radii of anaerobic centers within several aggregates, measured directly with the electrode, correlated with those calculated from a model of radial diffusion using measured respiration rates and the intra-aggregate O diffusion coefficient. Anaerobic centers were present in all aggregates that denitrified, but not all aggregates with anaerobic zones denitrified. The denitrification rate did not correlate with the size of the anaerobic zone, indicating that factors other than anaerobic volume contributed to the observed rates.

672 citations


Journal ArticleDOI
TL;DR: In this paper, the Phillips constraint theory of glass formation was applied to numerical simulations of vector percolation with nearest neighbor central forces, showing that the correct non-central vector threshold lies between the scalar and central vector thresholds.

634 citations


Journal ArticleDOI
TL;DR: In both normal and preeclamptic placentas, the production rates of thromboxane and prostacyclin were inhibited by indomethacin and not affected by arachidonic acid, so that their biologic actions on vascular tone, platelet aggregation, and uterine activity will be balanced.

596 citations


Journal ArticleDOI
TL;DR: The activities of sucrose phosphate synthase and acid invertase are significantly higher in the mutant than in the wild-type whereas ADP-glucose pyrophosphorylase activity is lower, suggesting that the activities of these enzymes may be modulated in response to metabolite concentrations or flux through the pathways.
Abstract: A mutant of Arabidopsis thaliana (L.) Heynh. which lacks leaf starch was isolated by screening for plants which did not stain with iodine. The starchless phenotype, confirmed by quantitative enzymic analysis, is caused by a single recessive nuclear mutation which results in a deficiency of the chloroplast isozyme of phosphoglucomutase. When grown in a 12-h photoperiod, leaves of the wild-type accumulated substantial amounts of starch but lower levels of soluble sugars. Under these conditions, the mutant accumulated relatively high levels of soluble sugars. Rates of growth and net photosynthesis of the mutant and wild-type were indistinguishable when the plants were grown in constant illumination. However, in a short photoperiod, the growth of the mutant was severely impaired, the rate of photosynthesis was depressed relative to the wild-type, and the rate of dark respiration, which was high following the onset of darkness, exhibited an uncharacteristic decay throughout the dark period. The altered control of respiration by the mutant, which may be related to the relatively high levels of soluble carbohydrate that accumulate in the leaf and stem tissue, is believed to be partially responsible for the low growth rate of the mutant in short days. The depressed photosynthetic capacity of the mutant may also reflect a metabolic adaptation to the accumulation of high levels of soluble carbohydrate which mimics the effects of alterations in source/sink ratio. The activities of sucrose phosphate synthase and acid invertase are significantly higher in the mutant than in the wild-type whereas ADP-glucose pyrophosphorylase activity is lower. This suggests that the activities of these enzymes may be modulated in response to metabolite concentrations or flux through the pathways.

542 citations


Journal ArticleDOI
TL;DR: Feminists have made important contributions to sociology, but they have yet to transform the basic conceptual frameworks of the field as mentioned in this paper, and the traditional subject matter of sociology fell into a co-optable middle ground.
Abstract: Feminists have made important contributions to sociology, but we have yet to transform the basic conceptual frameworks of the field. A comparison of sociology with anthropology, history, and literature–disciplines which have been more deeply transformed–suggests factors that may facilitate or inhibit feminist paradigm shifts. The traditional subject matter of sociology fell into a co-optable middle ground, neither as thoroughly male centered as in history or literature, nor as deeply gendered as in anthropology. In addition, feminist perspectives have been contained in sociology by functionalist conceptualizations of gender, by the inclusion of gender as a variable rather than as a theoretical category, and by being ghettoized, especially in Marxist sociology. Feminist rethinking is also affected by underlying epistemologies (proceeding more rapidly in fields based on interpretive rather than positivist understanding), and by the status and nature of theory within a discipline.

527 citations


Journal ArticleDOI
TL;DR: The first conclusive evidence that covalent glasses can be divided into two classes is presented by calculating the elastic properties of random networks with different average coordination: those with high average coordination and those with low average coordination.
Abstract: It is believed that covalent glasses can be divided into two classes: those with high average coordination (amorphous solids) and those with low average coordination (polymeric glasses). We present the first conclusive evidence that this division is correct by calculating the elastic properties of random networks with different average coordination $〈r〉$. The results show that the elastic constants depend predominantly on $〈r〉$ and go to zero when $〈r〉=2.4$ with an exponent $f=1.5\ifmmode\pm\else\textpm\fi{}0.2$.

Journal ArticleDOI
TL;DR: This article showed that negative factors could be generated by a relatively small portion of the respondents who fail to attend to the negative-positive wording of the items, which is a frequently occurring phenomenon in factor and cluster analysis of personality or attitude scale items.
Abstract: A frequently occurring phenomenon in factor and cluster analysis of personality or attitude scale items is that all or nearly all questionnaire items that are nega tively keyed will define a single factor. Although sub stantive interpretations of these negative factors are usually attempted, this study demonstrates that the negative factor could be produced by a relatively small portion of the respondents who fail to attend to the negative-positive wording of the items. Data were generated using three different correlation matrices, which demonstrated that regardless of data source, when only 10% of the respondents are careless in this fashion, a clearly definable negative factor is gener ated. Recommendations for instrument development and data editing are presented.

Journal ArticleDOI
TL;DR: The hypothesis explored in this paper is that this hierarchy is related to the conceptual accessibility of the intended referents of noun phrases that commonly occur in particular relational roles, with relations higher in the hierarchy typically occupied by noun phrases representing more accessible concepts.

Journal ArticleDOI
TL;DR: In this article, a characterization of the citizen as an evaluator of the president is developed and used to construct an equation of presidential approval, and an equation that explains presidential effectiveness in the legislative arena and illustrates the operation of public support as a presidential resource.
Abstract: The growth of public opinion measurement in the last 40 years has added a new dimension to the study of presidential behavior. Not only have public evaluations become more newsworthy, but the importance of public support as a resource and determinant of political survival has been enhanced. Recent scholarship on the presidency has documented the value of public support, attempted to identify its major determinants, and speculated about the manner in which presidents might influence these evaluations.This research is designed to integrate these concerns into a single model and thereby to examine the interdependence between public support as a product of citizen decisions and as a political resource. First, a characterization of the citizen as an evaluator of the president is developed and used to construct an equation of presidential approval. Next, we develop an equation that explains presidential effectiveness in the legislative arena and illustrates the operation of public support as a presidential resource. The public support and legislative effectiveness equations are specified as a simultaneous equation system, estimated, and evaluated. The results of the model are then used to expand the conventional wisdom about the determinants of public support, to examine the consequences of the reciprocal relationship between public support and legislative success, and to generate ex post forecasts of President Reagan's support from 1981 through 1983.

Journal ArticleDOI
TL;DR: It is shown that the width of the ``optic peak'' increases roughly linearly with the rms bond-angle distortion of the network, consistent with model-building experience which shows that it is impossible to construct fully bonded amorphous networks with \ensuremath{\Delta}${\ensureMath{\theta}}_{b}$.
Abstract: The Raman scattering from various model structures for amorphous silicon is computed. It is shown that the width of the ``optic peak'' increases roughly linearly with the rms bond-angle distortion \ensuremath{\Delta}${\ensuremath{\theta}}_{b}$ of the network. The experimentally observed linewidths lead to 7.7\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}\ensuremath{\Delta}${\ensuremath{\theta}}_{b}$\ensuremath{\le}10.5\ifmmode^\circ\else\textdegree\fi{}. The smaller linewidths (and hence angles) correspond to networks that have been annealed at higher temperatures. These results are consistent with model-building experience which shows that it is impossible to construct fully bonded amorphous networks with \ensuremath{\Delta}${\ensuremath{\theta}}_{b}$\ensuremath{\le}6.6\ifmmode^\circ\else\textdegree\fi{}.

Journal ArticleDOI
TL;DR: A dwarf mutant of Arabidopsis thaliana (L.) Heynh was found to be less sensitive to applied gibberellins than the wild type, and this character was controlled by one partially-dominant gene (denoted Gai) located on chromosome 1.
Abstract: A dwarf mutant of Arabidopsis thaliana (L.) Heynh. was found to be less sensitive to applied gibberellins than the wild type, and this character was controlled by one partially-dominant gene (denoted Gai) located on chromosome 1. This mutant resembled gibberellin-deficient mutants since not only stem growth, but also apical dominanace and seed germination were reduced. However, in contrast to the latter mutants, gibberellin does not reverse these effects in the Gai mutant. The insensitivity of the mutant could be quantified in much more detail in the recombinant of this mutation with the GA deficient mutant ga-1/ga-1. Endogenous gibberellins of the Gai mutant did not differ from the wild type either in quantity or composition. The data suggest that the gene controls a step involved in gibberellin action.

Journal ArticleDOI
TL;DR: In this article, a meta-analysis of 31 field studies of the size-performance relationship is presented, showing that subunit size and performance are nonsignificantly or negatively related, depending on the operationalization used to measure subunit performance.
Abstract: The authors thank Lawrence W. Foster for his collaboration and Michael K. Moch for his comments on earlier drafts of this paper. We also thank the Associate Editor and ASQ reviewers for their helpful guidance, and Sarah B. Dornbos for her diligent assistance. This paper presents a meta-analysis of 31 published field studies of the size-performance relationship. The metaanalysis indicates that the relationship between subunit size and performance differs from the relationship between organizational size and performance. Specifically, subunit size and subunit perfomance are nonsignificantly or negatively related, depending on the operationalization used to measure subunit performance. These results appear to be modestly consistent with free-rider and process-loss models of group behavior. However, organizational size and organizational productivity, defined as performance measured in absolute (nonratio) terms, are positively related to each other in contrast to review findings to date. Additionally, organizational size and organizational efficiency, defined as performance measured in relative (output-input) terms, are shown to exhibit no positive relationship to each other, casting doubt on the existence of a positive net relationship between organizational size and economies of scale.*

Journal ArticleDOI
TL;DR: Benthic community metabolism was studied on four stream systems located in different biomes in the United States to test the hypothesis that a transition in community metabolism will occur from a predominance of heterotrophy in headwaters to a predominances of autotro Murphy in mid-sized reaches, with a return to heterotrophic further downstream.
Abstract: Benthic community metabolism was studied on four stream systems located in different biomes in the United States: the eastern deciduous forest (Pennsylvania, PA, and Michigan, MI), the high desert (Idaho, ID), and the coniferous forest (Oregon, OR). Studies were designed to test the hypothesis advanced within the River Continuum Concept that a transition in community metabolism will occur from a predominance of heterotrophy in headwaters to a predominance of autotrophy in mid-sized reaches, with a return to heterotrophy further downstream. Both gross primary productivity (GPP) and community respiration (CR24) increased with downstream direction on all systems. Net daily metabolism (NDM, or GPP − CR24) shifted from heterotrophy (−NDM, GPP CR24) with downstream direction at all sites, supporting the hypothesis. Annual metabolism in the most upstream reach of all sites was dominated by respiration; however, the farthest downstream reach was not necessarily the most autotrophic. Site-specific factors affected manifestation of the trend. Photosynthesis predominated annual metabolism in reaches (designated 1–4 in order of increasing size) 2–4 in ID, 3 and 4 in OR, and 4 in MI. In PA annual photosynthesis was slightly greater than respiration only at Station 3. Photosynthesis was predominant most consistently in ID and respiration most often in PA. About half the reaches that were heterotrophic annually were autotrophic at one or more seasons. Annual means of benthic GPP, CR24 and NDM ranged from 0.16 to 3.37, 0.36 to 2.88 and −0.73 to 0.50 g O2 · m2 · d1, respectively. Metabolic rates were usually high in PA and MI (and sometimes ID) and almost always lowest in OR. Parameters accounting for most variance in multiple linear regression analyses of the combined metabolism data from all sites were indicators of stream size, photosynthetically active radiation, temperature, and chlorophyll a concentration.

Journal ArticleDOI
TL;DR: Vitreous surgery was used to remove epiretinal macular membranes in 328 cases, 184 of which had membranes that were considered idiopathic and 144 which were due to other causes, and visual results were significantly better and complications fewer.

Journal ArticleDOI
TL;DR: The observations are consistent with the possibility that alterations in MT compression during growth cone advance integrates MT assembly with the advance, and suggest a particular type of complementary force interaction underlying axonal shape; the neurite actin network under tension and neurite microtubules under compression.
Abstract: We report in this article that the retraction of PC 12 neurites, unlike that of other cultured neurons, is due to tension within the neurite. Retraction is rapid and independent of metabolic energy. Transection of one arm of a branched neurite immediately causes the remaining arm to take up a new equilibrium position between attachment points. Similarly, detachment of one growth cone of a cell causes the cell body to move to a new equilibrium position between the remaining neurites. These observations provide direct evidence for the suspension of the cell soma among a network of tensioned neurites. We used retraction as an assay for neurite tension to examine the role of actin filaments and microtubules in neurite support and elongation. Our data suggest that microtubules (MTs) within PC 12 neurites are under compression, supporting tension within the actin network. Treatment of cells with drugs that disrupt actin networks, cytochalasin D or erythro-9-[3-(2-hydroxynonyl)]adenosine eliminates retraction regardless of the absence of MTs, lack of adhesion to the substratum, or integrity of the neurite. Conversely, stimulation of actin polymerization by injection of phalloidin causes retraction of neurites. Treatments that depolymerize MTs, nocodazole or cold, cause retraction of neurites, which suggests that microtubules support this tension, i.e., are under compression. Stabilization of MTs with taxol stabilizes neurites to retraction and under appropriate circumstances can drive neurite extension. Taxol-stimulated neurite extension is augmented by combined treatment with anti-actin drugs. This is consistent with the actin network's normally exerting a force opposite that of MT assembly. Cytochalasin and erythro-9-[3-(2-hydroxynonyl)] adenosine were found to increase slightly the dose of nocodazole required for MT depolymerization. This is consistent with the postulated balance of forces and also suggests that alteration of the compression borne by the microtubules could serve as a local regulator for MT polymerization during neurite outgrowth.

Journal ArticleDOI
TL;DR: Results are consistent with the hypothesis that CO(2) is the species of inorganic carbon which crosses the plasmalemma and that extracellular carbonic anhydrase is required to replenish CO( 2) from HCO(3) (-) at high pH and indicate that both acetazolamide and the dextran-bound sulfonamide inhibit only the extacellular enzyme.
Abstract: Membrane-permeable and impermeable inhibitors of carbonic anhydrase have been used to assess the roles of extracellular and intracellular carbonic anhydrase on the inorganic carbon concentrating system in Chlamydomonas reinhardtii. Acetazolamide, ethoxzolamide, and a membrane-impermeable, dextran-bound sulfonamide were potent inhibitors of extracellular carbonic anhydrase measured with intact cells. At pH 5.1, where CO2 is the predominant species of inorganic carbon, both acetazolamide and the dextran-bound sulfonamide had no effect on the concentration of CO2 required for the half-maximal rate of photosynthetic O2 evolution (K0.5[CO2]) or inorganic carbon accumulation. However, a more permeable inhibitor, ethoxzolamide, inhibited CO2 fixation but increased the accumulation of inorganic carbon as compared with untreated cells. At pH 8, the K0.5(CO2) was increased from 0.6 micromolar to about 2 to 3 micromolar with both acetazolamide and the dextran-bound sulfonamide, but to a higher value of 60 micromolar with ethoxzolamide. These results are consistent with the hypothesis that CO2 is the species of inorganic carbon which crosses the plasmalemma and that extracellular carbonic anhydrase is required to replenish CO2 from HCO3− at high pH. These data also implicate a role for intracellular carbonic anhydrase in the inorganic carbon accumulating system, and indicate that both acetazolamide and the dextran-bound sulfonamide inhibit only the extracellular enzyme. It is suggested that HCO3− transport for internal accumulation might occur at the level of the chloroplast envelope.

Journal ArticleDOI
TL;DR: In this paper, three pragmatic researchers, Professors Gupta, Raj, and Wilemon, take another look at what causes the significant barriers that exist at the interface of two of the key product innovation functions.

Journal ArticleDOI
TL;DR: A statistic for determining the number of different textures in the image is developed and demonstrated and a theory regarding the information processing strategies in human vision motivates the development of a texture feature space.

Journal ArticleDOI
TL;DR: The results are in general agreement with the results reported previously and are used to support the conclusion that most of the H(2)-dependent methanogenesis in these ecosystems occurs as a consequence of direct interspecies H( 2) transfer between juxtapositioned microbial associations within flocs or consortia.
Abstract: We developed new techniques to measure dissolved H2 and H2 consumption kinetics in anoxic ecosystems that were not dependent on headspace measurements or gas transfer-limited experimentation. These H2 metabolism parameters were then compared with measured methane production rates, and estimates of H2 production and interspecies H2 transfer were made. The H2 pool sizes were 205 and 31 nM in sewage sludge from an anaerobic digestor and in sediments (24 m) from Lake Mendota, respectively. The H2 turnover rate constants, as determined by using in situ pool sizes and temperatures, were 103 and 31 h−1 for sludge and sediment, respectively. The observed H2 turnover rate accounted for only 5 to 6% of the expected H2-CO2-dependent methanogenesis in these ecosystems. Our results are in general agreement with the results reported previously and are used to support the conclusion that most of the H2-dependent methanogenesis in these ecosystems occurs as a consequence of direct interspecies H2 transfer between juxtapositioned microbial associations within flocs or consortia.

Journal ArticleDOI
TL;DR: A microscopic theory is presented which explains for the first time simultaneously both the observed collective flow and the pion multiplicity and gives their dependence on the nuclear equation of state.
Abstract: Nuclear collisions from 0.3 to 2 GeV/nucleon are studied in a microscopic theory based on Vlasov's self-consistent mean field and Uehling-Uhlenbeck's two-body collision term which respects the Pauli principle. The theory explains simultaneously the observed collective flow and the pion multiplicity and gives their dependence on the nuclear equation of state.

Journal ArticleDOI
TL;DR: A distributed algorthim for load balancing which is network topology independent is proposed in this paper and the main objective of this paper is to describe the dynamic process migration protocol based on the proposed drafting algorithm.
Abstract: It is desirable for the load in a distributed system to be balanced evenly. A dynamic process migration protocol is needed in order to achieve load balancing in a user transparent manner. A distributed algorthim for load balancing which is network topology independent is proposed in this paper. Different network topologies and low-level communications protocols affect the choice of only some system design parameters. The "drafting" algorithm attempts to compromise two contradictory goals: maximize the processor utilization and minimize the communication overhead. The main objective of this paper is to describe the dynamic process migration protocol based on the proposed drafting algorithm. A sample distributed system is used to further illustrate the drafting algorithm and to show how to define system design parameters. The system performance is measured by simulation experiments based on the sample system.

Journal ArticleDOI
TL;DR: In this article, a comprehensive comparison of experimentally observed Gamow-Teller beta decay with theory is presented for the sd-shell (A = 17-39) nuclei.

Journal ArticleDOI
TL;DR: It is shown that effective-medium theory gives an excellent description of regular lattices when nearest-neighbor central-force springs are present with probability p with all the elastic constants going to zero at p = c = d where d is the dimension and c is the ordinary percolation threshold.
Abstract: We show that effective-medium theory gives an excellent description of regular lattices when nearest-neighbor central-force springs are present with probability p. Effective-medium theory shows that all the elastic constants go to zero at ${p}_{\mathrm{cen}={\mathrm{dp}}_{c}}$ where d is the dimension and ${p}_{c}$ is the effective-medium estimate of the ordinary percolation threshold.


Journal ArticleDOI
TL;DR: A training study was conducted with 59 sixth grade students, finding that the training appeared to be most facilitative for those of average and lower ability levels, consistent with similar findings in other studies that trained cognitive skills.
Abstract: The ubiquity of oral and written questions in classrooms and reading tasks has been well established. It is obvious that students’ background knowledge is a primary determinant of how well they can answer comprehension-promoting or assessment-oriented questions. Less obvious is the need to access appropriate sources of information used in answering questions. A training study was conducted with 59 sixth grade students of high, average, and low reading ability levels, instructing half of students in each ability level in the relationship of a question, the text to which the question refers, and the reader’s knowledge base. Repeated measures multivariate analyses of variance on two passages indicate that the training enhanced students’ understanding of task demands of questions and their answer quality as measured by (a) their ability to correctly identify the question-answer relationship represented, (b) their consistency in providing an answer from the source of information they had indicated they were us...