Showing papers by "Michigan State University published in 1988"

Transfer of training: a review and directions for future research

Abstract: Transfer of training is of paramount concern for training researchers and practitioners. Despite research efforts, there is a growing concern over the “transfer problem.” The purpose of this paper is to provide a critique of the existing transfer research and to suggest directions for future research investigations. The conditions of transfer include both the generalization of learned material to the job and the maintenance of trained skills over a period of time on the job. The existing research examining the effects of training design, trainee, and work-environment factors on conditions of transfer is reviewed and critiqued. Research gaps identified from the review include the need to (1) test various operationalizations of training design and work-environment factors that have been posited as having an impact on transfer and (2) develop a framework for conducting research on the effects of trainee characteristics on transfer. Needed advancements in the conceptualization and operationalization of the criterion of transfer are also discussed.

Coordinating Coordination Failures in Keynesian Models

Abstract: This paper focuses on the importance of strategic complementarities in agents’ payoff functions as a basis for macroeconomic coordination failures. Strategic complementarities arise when the optimal strategy of an agent depends positively upon the strategies of the other agents. We first analyze an abstract game and find that multiple equilibria and a multiplier process may arise when strategic complementarities are present. Often these equilibria can be Pareto ranked. We then place additional economic content on the analysis of this game by considering strategic complementarities arising from production functions, matching technologies, and commodity demand functions in a multisector, imperfectly competitive economy. C 1988 by the President and Fellows of Harvard College and the Massachusetts Institute of Technology. © 1988 by the President and Fellows of Harvard College and the Massachusetts Institute of Technology.

GAL4-VP16 is an unusually potent transcriptional activator

Abstract: Recent work has defined a class of transcriptional activators1–5, members of which activate transcription in yeast, plant, insect and mammalian cells6–9. These proteins contain two parts: one directs DNA binding and the other, called the activating region, presumably interacts with some component of the transcriptional machinery. Activating regions are typically acidic and require some poorly-understood aspect of structure, probably at least in part an α-helix1–5,10. Here we describe a new member of this class, formed by fusing a DNA-binding fragment of the yeast activator GAL4 to a highly acidic portion of the herpes simplex virus protein VP16 (ref. 11; also called Vmw65). VP16 activates transcription of immediate early viral genes by using its amino-terminal sequences to attach to one or more host-encoded proteins that recognise DNA sequences in their promoters11–15. We show that the hybrid protein (GAL4-VP16) activates transcription unusually efficiently in mammalian cells when bound close to, or at large distances from the gene. We suggest that the activating region of VP16 may be near-maximally potent and that it is not coincidental that such a strong activator is encoded by a virus.

Insensitivity to Ethylene Conferred by a Dominant Mutation in Arabidopsis thaliana

Abstract: Ethylene influences a number of developmental processes and responses to stress in higher plants. The molecular basis for the action of ethylene was investigated in mutants of Arabidopsis thaliana that have altered responses to ethylene. One mutant line, which has a dominant mutation at a locus designated etr, lacks a number of responses to ethylene that are present in the wild-type plant. These include inhibition of cell elongation, promotion of seed germination, enhancement of peroxidase activity, acceleration of leaf senescence, and feedback suppression of ethylene synthesis by ethylene. These diverse responses, which occur in different tissues of Arabidopsis, appear to share some common element in their transduction pathways—for example, a single receptor for ethylene. Results of ethylene binding experiments in vivo indicate that this receptor may be affected by the etr mutation.

Synthesizing standardized mean‐change measures

Abstract: A new approach is presented for the meta-analysis of data from pre-test-post-test designs. With this approach, data from studies using different designs may be compared directly and studies without control groups need not be omitted. The approach is based on a ‘standardized mean-change’ measure, computed for each sample within a study, and involves analysis of the standardized mean changes and differences in the standardized mean changes. Analyses are illustrated using results of studies of the effectiveness of mental practice on motor-skill development.

Transaction cost analysis of strategy‐structure choice

Abstract: Using a transaction cost approach this paper analyzes the relationship between strategy, structure and organizational performance. It addresses three related questions. First, what determines the limit to growth through internalization for a firm pursing a particular strategy? Second, why does a firm pursue different strategies for achieving growth? Third, what determines changes in the strategy and structure used by the firm over time? This analysis serves to integrate work in strategic management and provides a framework for analyzing corporate strategy choice.

Conflict among personal strivings: immediate and long-term implications for psychological and physical well-being.

Abstract: We examined the influence of goal conflict and ambivalence on psychological and physical well-being through the personal striving framework. Eighty-eight undergraduates in two studies listed 15 of their personal strivings and rated them on the amount of conflict experienced between them and ambivalence experienced about each. Diary and experience sampling methods were used to assess positive and negative affect and physical symptomatology. Conflict and ambivalence were associated with high levels of negative affect, depression, neuroticism, and psychosomatic complaints. Conflict was also associated with health center visits and illnesses over the past year. A 1-year follow-up demonstrated that conflict and ambivalence ratings were stable and that these ratings predicted psychosomatic complaints over time. In a third study, undergraduates' thoughts and activities were randomly sampled over a 3-week period. Subjects were less likely to act on conflictful and ambivalent strivings but to spend more time thinking about these strivings.

Primary structure of prostaglandin G/H synthase from sheep vesicular gland determined from the complementary DNA sequence.

Abstract: Prostaglandin G/H synthase (8,11,14-icosatrienoate, hydrogen-donor:oxygen oxidoreductase, EC 1.14.99.1) catalyzes the first step in the formation of prostaglandins and thromboxanes, the conversion of arachidonic acid to prostaglandin endoperoxides G and H. This enzyme is the site of action of nonsteroidal anti-inflammatory drugs. We have isolated a 2.7-kilobase complementary DNA (cDNA) encompassing the entire coding region of prostaglandin G/H synthase from sheep vesicular glands. This cDNA, cloned from a lambda gt 10 library prepared from poly(A)+ RNA of vesicular glands, hybridizes with a single 2.75-kilobase mRNA species. The cDNA clone was selected using oligonucleotide probes modeled from amino acid sequences of tryptic peptides prepared from the purified enzyme. The full-length cDNA encodes a protein of 600 amino acids, including a signal sequence of 24 amino acids. Identification of the cDNA as coding for prostaglandin G/H synthase is based on comparison of amino acid sequences of seven peptides comprising 103 amino acids with the amino acid sequence deduced from the nucleotide sequence of the cDNA. The molecular weight of the unglycosylated enzyme lacking the signal peptide is 65,621. The synthase is a glycoprotein, and there are three potential sites for N-glycosylation, two of them in the amino-terminal half of the molecule. The serine reported to be acetylated by aspirin is at position 530, near the carboxyl terminus. There is no significant similarity between the sequence of the synthase and that of any other protein in amino acid or nucleotide sequence libraries, and a heme binding site(s) is not apparent from the amino acid sequence. The availability of a full-length cDNA clone coding for prostaglandin G/H synthase should facilitate studies of the regulation of expression of this enzyme and the structural features important for catalysis and for interaction with anti-inflammatory drugs.

DNA Probe Method for the Detection of Specific Microorganisms in the Soil Bacterial Community

Abstract: We developed a protocol which yields purified bacterial DNA from the soil bacterial community. The bacteria were first dispersed and separated from soil particles in the presence of polyvinylpolypyrrolidone, which removes humic acid contaminants by adsorption to this insoluble polymer. The soil bacteria were then collected by centrifugation and lysed by using a comprehensive protocol designed to maximize disruption of the various types of bacteria present. Total bacterial DNA was purified from the cell lysate and remaining soil contaminants by using equilibrium density gradients. The isolated DNA was essentially pure as determined by UV spectral analysis, was at least 48 kilobases long, and was not subject to degradation, which indicated that there was no contaminating nuclease activity. The isolated DNA was readily digested by exogenously added restriction endonucleases and successfully analyzed by slot blot and Southern blot hybridizations. Using single-stranded, P-labeled DNA probes, we could detect and quantitate the presence of a specific microbial population in the natural soil community on the basis of the presence of a DNA sequence unique to that organism. The sensitivity of our methodology was sufficient to detect Bradyrhizobium japonicum at densities as low as 4.3 x 10 cells per g (dry weight) of soil, which corresponds to about 0.2 pg of hybridizable DNA in a 1-mug DNA sample.

Asking the Right Questions About Teacher Preparation: Contributions of Research on Teacher Thinking

Abstract: Research on teacher thinking has established a place for itself within the international educational research enterprise. What is not so clear is how studies of teacher thinking may be of use in improving the quality of teacher preparation programs. This paper promotes a consultant role for researchers on teacher thinking in relation to teacher educators. The current state of knowledge about teacher thinking is summarized under three headings: Preconceptions and Implicit Theories, Planning and Reflection, and Dilemmas and Uncertainty. After each summary, a list of questions is offered as food for thought in the pursuit of understanding and improving learning to teach. The author claims that research on teacher thinking can improve teacher preparation by encouraging thoughtful teacher educators to ask better questions of themselves and of their arts.

A linear model of muscle respiration explains monoexponential phosphocreatine changes

Abstract: Phosphocreatine (PCr) content was measured by phosphorus nuclear magnetic resonance spectroscopy in the gastrocnemius muscles of pentobarbital-anesthetized rats during and after twitch stimulation at rates up to 0.75 Hz. The monoexponential time constant for PCr changes was similar at the onset of vs. during recovery after stimulation and was not significantly different for different stimulation rates (mean time constant 1.44 min). Steady-state PCr level during stimulation was linearly related to the product of stimulation rate times peak twitch force. These results are shown to be consistent with a simple first-order electrical analog model of oxidative metabolism that is applicable at submaximal oxidative rates. The model assumes equilibrium of the creatine kinase reaction, which is modeled as a chemical capacitor, with capacitance proportional to the total creatine level, and PCr level proportional to the cytosolic free energy of ATP hydrolysis.

Genetic differentiation between sympatric host races of the apple maggot fly Rhagoletis pomonella

Abstract: It has been proposed that true fruit flies in the Rhagoletis pomonella species group speciate sympatrically (that is, in the absence of geographic isolation) as a consequence of shifts to previously unexploited host plants1,2. Because Rhagoletis larvae are host-specific fruit parasites and mate selection in these flies is directly coupled to host-plant recognition3–5, variation for larval survivorship and host preference traits can act as genetically based barriers to gene flow. This reduction in gene flow results in the sympatric divergence of fly populations adapted to alternative hosts. The shift of R. pomonella from its native host hawthorn (Crataegus spp.) to domestic apples (Mains pumila) in eastern North America in the past 200 years6 provides an opportunity to determine whether host specialization is sufficient to differentiate populations without earlier periods of geographic isolation. We report finding genetic differentiation between co-occurring hawthorn and apple populations of R. pomonella at a field site near Grant, Michigan. The result confirms that hawthorn and apple flies represent partially reproductively isolated 'host races' and is consistent with a sympatric mode of divergence for these flies.

Stereotypic biases in social decision making and memory: testing process models of stereotype use.

Abstract: Two information-processing mechanisms that could potentially contribute to judgmental discrimination against the members of stereotyped social groups were examined in two experiments, using a mock juror decision-making task. Both postulated mechanisms involve biased processing of judgment-relevant evidence. The interpretation hypothesis asserts that the activation of stereotypic concepts influences the perceived probative implications of other evidence. The selective processing hypothesis asserts that stereotype-consistent evidence is processed more extensively than is inconsistent evidence. Judgment and memory data from the first experiment supported the general notion that stereotype-based discrimination emerges from biased evidence processing. The specific pattern of results supported selective processing rather than interpretation biases as the critical process underlying observed judgmental discrimination. The second experiment corroborated this conclusion by showing that a manipulation that prevents selective processing of the evidence effectively eliminated biases in judgments and recall pertaining to stereotyped targets. Implications for a general understanding of stereotyping and discrimination are discussed.

Directed mutagenesis indicates that the donor to P 680+ in photosystem II is tyrosine-161 of the D1 polypeptide

Abstract: Photosystem II contains two redox-active tyrosines. One of these, Y{sub Z}, reduces the reaction center chlorophyll, P680, and transfers the oxidizing equivalent to the oxygen-evolving complex. The second, Y{sub D}, has a long-lived free radical state of unknown function. The authors, recently established that Y{sub D} is Tyr-160 of the D2 polypeptide by site-directed mutagenesis of a psbD gene in the unicellular cyanobacterium Synechocystis 6803. Y{sub Z} is most likely the symmetry-related Tyr-161 of the D1 polypeptide. To test this hypothesis, they have changed Tyr-161 to phenylalanine by site-directed mutagenesis of a psb A gene in Synechocystis. The resulting mutant assembles PSII, as judged by its ability to produce the stable Y{sup +}{sub D} radical, but is unable to grow photosynthetically and exhibits altered fluorescence properties. The nature of the fluorescence change indicates that forward electron transfer to P{sup +}{sub 680} is disrupted in the mutant. These results provide strong support for our identification of Tyr-161 in the D1 polypeptide with Y{sub Z}.

Toward a More Appropriate Conceptualization of Research on School Effects: A Three-Level Hierarchical Linear Model

Abstract: Two aspects of educational research--that children's learning is typically the object of inquiry and that this learning usually occurs in organizational settings of classrooms and schools--locate educational research at the nexus of two of the most troublesome and persistent methodological problems in the social sciences: the measurement of change and the "unit-of-analysis" problems. Over the past several years, a satisfactory solution to these problems has been developed through the use of hierarchical linear models. This article summarizes these developments and shows how these techniques have already been used to illuminate important substantive questions about the effects of school organization and children's language development. In the final section of the article, the authors introduce a three-level hierarchical model that they argue should constitute the basic paradigm for future quantitative research on student learning.

Site-directed mutagenesis identifies a tyrosine radical involved in the photosynthetic oxygen-evolving system

Abstract: Photosynthetic oxygen evolution takes place in the thylakoid protein complex known as photosystem II. The reaction center core of this photosystem, where photochemistry occurs, is a heterodimer of homologous polypeptides called D1 and D2. Besides chlorophyll and quinone, photosystem II contains other organic cofactors, including two known as Z and D. Z transfers electrons from the site of water oxidation to the oxidized reaction center primary donor, P+.680, while D+. gives rise to the dark-stable EPR spectrum known as signal II. D+. has recently been shown to be a tyrosine radical. Z is probably a second tyrosine located in a similar environment. Indirect evidence indicates that Z and D are associated with the D1 and D2 polypeptides, respectively. To identify the specific tyrosine residue corresponding to D, we have changed Tyr-160 of the D2 polypeptide to phenylalanine by site-directed mutagenesis of a psbD gene in the cyanobacterium Synechocystis 6803. The resulting mutant grows photosynthetically, but it lacks the EPR signal of D+.. We conclude that D is Tyr-160 of the D2 polypeptide. We suggest that the C2 symmetry in photosystem II extends beyond P680 to its immediate electron donor and conclude that Z is Tyr-161 of the D1 polypeptide.

Spatial Variability in a Successional Plant Community: Patterns of Nitrogen Availability

Abstract: We examined the spatial variability of N mineralization, nitrification, and denitrification at a resolution of 1 m over a 0.5-ha portion of an old field in southeast Michigan. Net mineralization and nitrification rates were estimated from changes in am- monium and nitrate during 45-d laboratory incubations of soil from >300 individual sample locations. Denitrification was estimated from nitrous oxide accumulation rates during 24-h incubations of intact cores (n = 252) under acetylene atmospheres at a pressure of 10 kPa. We used geostatistical procedures to characterize the spatial distributions of these and other soil variates. Semivariograms for all three N transformations showed a high degree of spatial de- pendence among points sampled within 1-40 m of one another. Nugget variances were 27-37% of structural variances, indicating that most of the variation within the sample populations for these rates could be attributed to spatial autocorrelation at a scale > 1 m. Isopleths calculated using punctual kriging algorithms show a nonuniform distribution of these transformations across the field. High rates of all processes occurred in swales on the northern edge of the sample area, but also occurred elsewhere in the field on drier, more level sites. These results indicate that spatial characteristics of the measured nitrogen transfor- mations in this old field are complex, and that only some of this complexity is associated with surface topography. Whether spatial complexity affects or mainly reflects plant com- munity structure is not known, but this small-scale heterogeneity may influence existing plant and microbial population dynamics and should be considered by those attempting to understand community dynamics or to quantify ecosystem-level nutrient fluxes.

Reductive dechlorination of polychlorinated biphenyls by anaerobic microorganisms from sediments

Abstract: Microorganisms from Hudson River sediments reductively dechlorinated most polychlorinated biphenyls (PCBs) in Aroclor 1242 under anaerobic conditions, thus demonstrating PCB dechlorination by anaerobic bacteria in the laboratory. The most rapid dechlorination was observed at the highest PCB concentration used; at 700 parts per million Aroclor, 53 percent of the total chlorine was removed in 16 weeks, and the proportion of mono- and dichlorobiphenyls increased from 9 to 88 percent. Dechlorination occurred primarily from the meta and para positions; congeners that were substituted only in the ortho position (or positions) accumulated. These dechlorination products are both less toxic and more readily degraded by aerobic bacteria. These results indicate that reductive dechlorination may be an important environmental fate of PCBs, and suggest that a sequential anaerobic-aerobic biological treatment system for PCBs may be feasible.

Isolation and characterization of a starchless mutant of Arabidopsis thaliana (L. ) Heynh lacking ADPglucose pyrophosphorylase activity

Abstract: A mutant of Arabidopsis thaliana lacking ADPglucose pyrophosphorylase activity (EC 2.7.7.27) was isolated (from a mutagenized population of plants) by screening for the absence of leaf starch. The mutant grows as vigorously as the wild type in continuous light but more slowly than the wild type in a 12 hours light/12 hours dark photoperiod. Genetic analysis showed that the deficiency of both starch and ADPglucose pyrophosphorylase activity were attributable to a single, nuclear, recessive mutation at a locus designated adg1. The absence of starch in the mutant demonstrates that starch synthesis in the chloroplast is entirely dependent on a pathway involving ADPglucose pyrophosphorylase. Analysis of leaf extracts by two-dimensional polyacrylamide gel electrophoresis followed by Western blotting experiments using antibodies specific for spinach ADPglucose pyrophosphorylase showed that two proteins, present in the wild type, were absent from the mutant. The heterozygous F1 progeny of a cross between the mutant and wild type had a specific activity of ADPglucose pyrophosphorylase indistinguishable from the wild type. These observations suggest that the mutation in the adg1 gene in TL25 might affect a regulatory locus.

McrA and McrB restriction phenotypes of some E.coli strains and implications for gene cloning

Abstract: The McrA and McrB (modified cytosine restriction) systems of E. coli interfere with incoming DNA containing methylcytosine. DNA from many organisms, including all mammalian and plant DNA, is expected to be sensitive, and this could interfere with cloning experiments. The McrA and B phenotypes of a few strains have been reported previously (1-4). The Mcr phenotypes of 94 strains, primarily derived from E. coli K12, are tabulated here. We briefly review some evidence suggesting that McrB restriction of mouse-modified DNA does occur in vivo and does in fact interfere with cloning of specific mouse sequences.

Pectins as mediators of wall porosity in soybean cells.

Abstract: The non-invasive technique of fluorescence redistribution after photobleaching was employed on soybean (Glycine max (L.) Merr.) root cells grown in suspension culture to examine macromolecular transport across plant cell walls. Using both fluorescently derivatized dextrans and proteins of graded size, a functional range of diameters for putative trans-wall channels was determined to be 6.6-8.6 nm. A mild treatment with pectinase apparently enlarged the channels, without adversely affecting cell viability, enabling significantly larger molecules to pass through the wall. Treatment of the cells with cellulysin or protease did not have this enlargement effect. It appears that the organization of pectic substances is a major control element in defining the sieving properties of the wall.