High Degree Of Cooperation Research Articles

The Results of Four Wisconsin Focus Groups: Roles of Husbands and Wives in Farm Decisions

The study consisted of four gender-segregated focus groups in which farm couples were asked to describe an actual and a hypothetical farm decision. We used this study to triangulate the findings of a survey of six hundred couples on farm decision making. We also used it to formulate a theoretical model of farm decision making and to determine which explanatory variables to include. The findings indicate that while couples exhibit a high degree of cooperation, share goals, and make long-term decisions jointly, they have different preferences and different spheres of influence and decision making on the farm. This points to a cooperative bargaining model of decision-making behavior. Factors that most influenced decision making were age, debt load, and wives' off-farm income.

Flexible Regions of RNA Structure Facilitate Co-operative Rev Assembly on the Rev-response Element

The oligomerisation of Rev on the Rev-response element (RRE) was studied using a series of model substrates. Only a monomer of Rev is able to bind efficiently to a high affinity site that is flanked by perfect duplex RNA. Addition of a bulge or a second stem structure adjacent to the high affinity site permits the co-operative incorporation of a second Rev molecule to the RNA. Model RREs carrying bulges can bind Rev with a higher degree of co-operativity than the native structure. Oligomerisation was efficient when the bulge was moved to the opposite strand of the duplex, but was severely impaired when the distance between the bulge and the high affinity site was increased by more than 8 bp. Rev can oligomerise at either end of the RNA – protein complex formed at the high affinity site; when the duplex flanking a high affinity site is disrupted by a bulge or a stem, oligomerisation proceeds in the direction of the disruption regardless of the orientation of the high affinity site. The results are consistent with the "molecular rheostat" model for RRE function, which suggests that Rev binding to the RRE is highly distributive and provides a sensitive measurement of intracellular Rev concentrations.

Thermal unfolding of Acanthamoeba myosin II and skeletal muscle myosin

Studies on the thermal unfolding of monomeric Acanthamoeba myosin II and other myosins, in particular skeletal muscle myosin, using differential scanning calorimetry (DSC) are reviewed. The unfolding transitions for intact myosin or its head fragment are irreversible, whereas those of the rod part and its fragments are completely reversible. Acanthamoeba myosin II unfolds with a high degree of cooperativity from ca. 40–45°C at pH 7.5 in 0.6 M KCl, producing a single, sharp endotherm in DSC. In contrast, thermal transitions of rabbit skeletal muscle myosin occur over a broader temperature range (ca. 40–60°C) under the same conditions. The DSC studies on the unfolding of the myosin rod and its fragments allow identification of cooperative domains, each of which unfolds according to a two-state mechanism. Also, DSC data show the effect of the nucleotide-induced conformational changes in the myosin head on the protein stability.

Sequential ordered mechanism for the sodium-glutamate transport in intestinal brush border membrane vesicles

The glutamate/aspartate carrier localized in the brush-border membrane vesicles from enterocytes is known as a transport system catalyzing a sodium-substrate cotransport driven by the sodium gradient across the membrane. The kinetics of this transport system is studied by analogy with an enzymatic bi-substrate reaction. The results of this approach can be summarized as follows: (1) The dependence of the l-glutamate transport rate on the sodium concentration is sigmoidal, and the stoichiometry of the transport is 2 Na +/1 glutamate/1 carrier molecule. (2) The mechanism is sequential ordered, with l-glutamate binding after both the sodium cations. In addition, there is a very high degree of cooperativity between the two sodium binding sites.

Denaturant unfolding of the ferric enterobactin receptor and ligand-induced stabilization studied by site-directed spin labeling.

FepA is an integral outer membrane protein that is the specific receptor for the siderophore, ferric enterobactin, and is thus primarily responsible for iron uptake in many Gram-negative bacteria. A site-specific mutant of FepA, containing a single introduced cysteine in the ligand-binding domain, was spin labeled and used to examine the denaturant-induced unfolding of this receptor with guanidine hydrochloride (Gdn-HCl) and urea. Electron spin resonance (ESR) spectra showed conversion of the spin label from a motionally-restricted, immobilized environment to a freely-accessible, rotationally-mobile state upon denaturation. Unfolding was also followed by nondenaturing polyacrylamide gel electrophoresis (PAGE), which is sensitive to loss of the putative transmembrane beta-structure, and displayed a similar concentration dependence. Unfolding occurred over relatively narrow ranges of denaturant concentration, indicating a high degree of cooperativity. Unfolding was fully reversible under the conditions employed. Rapid, spontaneous refolding occurred in the presence of Triton X-100 and did not require exogenous lipids. Refolding could be induced by either dialysis, dilution to low denaturant concentration, or ethanol precipitation. At ambient temperature the free energy of unfolding extrapolated to zero denaturant concentration (delta GU zero) was 6.24 +/- 0.63 kcal/mol. Values of delta GU zero obtained with Gdn-HCl and urea were in good agreement, as were values obtained from linear extrapolation and nonlinear regression fitting to a two-state equilibrium. This is the first report of a quantitative evaluation of the free energy of unfolding for an integral membrane protein.

Early biological morphogenesis and nonlinear dynamics

Biological pattern formation is a process that so far has gone largely unexplained. Mechanisms for cellular differentiation, and pattern forming processes, must both have emerged within the same short time interval. It now seems unlikely that the great diversity of observed patterns can be accounted for by the action of one or a few specific patterning genes, or, in its extreme form, the idea that there might be a single such proto pattern gene. Many seemingly related pattern forming processes, such as segment formation, depend on unrelated genetic mechanisms. Thus another common feature as a proto pattern gene is needed to understand the onset of pattern formation. Experimental biologists favour mechanisms in which morphogenetic gradients are the main source of positional information. Specific combinations of genes (cues) are activated differentially by thresholds along particular regions on the gradient. Among theoreticians the pattern forming processes are believed to some extent to be dependent upon true symmetry breaking processes, which can occur in most nonlinear control systems, of which the Turing mechanism is an example. It is argued here that the common fundamental feature of gene control systems is a high degree of cooperativity. Such highly nonlinear systems may originally have been capable of reading subtle differences in the concentration of a controller, but the evolutionary pressure to refine this kind of processes in single cells would eventually have led to gene clusters with steep off-on control, and this is seen experimentally in many such systems. Some nonlinear systems of this type have for some time been known among theoreticians to be prone to multistability (a necessary precondition for cell differentiation), chemical time oscillations and spontaneous spatial pattern formation by Turing’s mechanism. Increasing cooperativity in the defining rate laws greatly facilitates the tendency for such phenomena to arise, and we demonstrate this explicitly for Turing pattern formation. We argue that all these phenomena arose simultaneously with the capability of interpreting positional information along simple gradients.

GABAergic inhibition of crayfish deep extensor abdominal muscle exhibits a steep dose-response relationship and a high degree of cooperativity

A patch-clamp study was done to characterize the recently found GABAergic (i.e. gamma-aminobutyric acid) inhibitory synaptic channels of crayfish deep extensor abdominal muscle. Outside-out patches were rapidly activated by GABA to measure the dose/response curves for the open probability of the channels, Po, and the rise time, tr, (time from Po = 0.1 to Po = 0.9). In some of the patches the GABA-activated currents decayed due to desensitization and such patches were not studied further. Rare channel openings were elicited with 0.1 mM GABA. The Po at this low concentration of GABA was 0.0005 to 0.01. Application of 10 mM GABA was necessary to reach the maximal Po of 0.9. The slope of the dose/response relationship in the double logarithmic plot was 5.4 +/- 1.1 (mean +/- SD; n = 9) between 0.1 mM and 0.2 mM GABA. The plot of tr versus GABA concentration had a peculiar shape, recently found to be characteristic for positive cooperativity of the binding sites. tr increased from a minimum at 10 mM GABA with declining concentrations of GABA and reached a peak at 0.4 mM GABA. Below 0.4 mM GABA, tr decreased again. With 0.2 mM GABA tr was 0.40 +/- 0.1 (mean +/- SD; n = 4) of the peak value measured at 0.4 mM GABA. Simulations were compared with the experimental results and a linear reaction scheme with five binding sites for GABA was established to describe the dose/response curves for Po and tr.

Toward lean management? international transferability of Japanese management strategies to Australia

AbstractThere has been growing international interest in the “lean production” notion with present Japanese car plants as the paragon of this work system. Yet despite its Japanese origins many commentators have taken for granted that this Japanese notion can readily be transferred to other contexts and that it is a preferable alternative to Fordist mass production. Lean management involves continuous improvement, just‐in‐time techniques, total quality management, and team based work organization. These techniques have led to demonstrable major improvements in the efficiency of manufacturing enterprises in Southeast Asia, Japan, Europe, and the U.S., as shown by numerous studies. However, there has been little research on the possible transferability of such Japanese management strategies to Australia, which does not have a reputation for having highly committed workers or compliant unions. Therefore, the introduction of lean management in Australia deserves examination. After summarizing the context of the Australian car industry and the literature on lean production, we report on our study of a major car plant, which is based on interviews, observation, and a survey of employees. We were fortunate in having a high degree of cooperation from the company, unions, and government, because this independent study was initiated jointly by these three parties, which is relatively unusual for such research. Although we report several criticisms of lean production, we conclude that, especially when coupled with industry restructuring, lean production can potentially contribute to a substantial improvement in manufacturing competitiveness. © 1995 John Wiley & Sons, Inc.

Substituent effects on the physical properties of (μ-oxo)(μ-carboxylato)bis{tris(2-pyridylmethyl) aminechromium(III)} dimers

In order to document the influence of carboxylate substituents on the physical properties of [(tmpa)Cr(μ-O)(μ- RCO 2)Cr(tmpa)] 3+ dimers, electronic spectra, Cr(III,IV/III,III) half-wave reduction potentials, μ-OH − ionization constants and antiferromagnetic coupling constants are reported for R=CH 2Cl, CHCl 2, C(CH 3) 3, C(C 6H 5) 3, 1- adamantyl and Ph-4-X (X=NMe 2, OH, OCH 3, CH 3, CF 3, F, Cl, CN, NO 2); tmpa=tris(2-pyridylmethyl)amine. Inductive effects of bridging benzoato para substituents are transmitted effectively to the μ-O 2− group in [(tmpa)Cr(μ-O)(μ-4-X-PhCO 2)Cr(tmpa)] 3+ dimers. A linear free energy relationship between E 1/2 Cr(III,IV/ III,III) and p K a(Cr(μ-OH)Cr) indicates a high degree of cooperativity among bridging oxo, complementary bridging and non-bridging ligands with regard to π-donation towards the Cr(III) centers. Trends in antiferromagnetic coupling constants are interpreted through the influence of configuration interaction between ligand- and metal- centered b 1 symmetry orbitals on the HOMO(b 1)-LUMO(a 2) singlet-triplet energy gap.

A Fokker-Planck description of multivalent interactions

A dynamic model is presented which uses a mean first passage time to characterize multivalent binding as the continuum limit of a one-step stochastic process. The use of a stochastic model instead of a model based on rate equations permits consideration of fluctuations in the number of bonds formed. The importance of fluctuations to the problem of multivalent interactions, especially low affinity interactions, is discussed. Assumptions for the theory are based on data in which liposomes were used as a model system for multivalency. The data suggest a linear sequential process of bond rupture, and thus a high degree of cooperativity in the microscopic events associated with multivalent liposomal binding.

Integrating domains of work stress and industrial relations: Introduction and overview

During the past decade, there has been a growing interest in the literature on stress at work, from both theoretical and empirical perspectives (e.g. Cohen 1980; Cooper and Payne, 1988; Jackson and Schuler, 1985; Kahn and Byosiere, 1992). The experience of stress at work has been singled out as an important area of investigation because of its potential effect on the well-being and productivity of employees. Reviews of the literature have clearly indicated that a variety of work stressors such as role ambiguity, role conflict, and insuffient control and authority at work tend to be associated with psychological strains (e.g. burnout, psychosomatic complaints) as well as adverse behavioral (e.g. absenteeism, turnover) and physiological (e.g. blood pressure, heart rate) outcomes (see e.g. Cooper and Marshall, 1976; Fried, Rowland and Ferris, 1984; Jackson and Schuler, 1985; Shirom, 1989 for reviews). The severe implications of work stress have also led scholars and researchers to search for potential coping mechanisms to reduce the experiences of stress and strain at work. Among these mechanisms, emotional and instrumental social support have been the most extensively examined and appear to be beneficial for reducing stress and strain (Cohen and Wills, 1985; House, 1981). Yet, our knowledge concerning the issues of work stress its causes and effects as well as mechanisms utilized to cope with or overcome it appears to be incomplete. In particular, past research has failed to incorporate sufficiently relevant concepts and variables from other potentially related areas. Very little attention, for example, has been given in the work stress literature to relevant domains in the field of industrial relations (e.g. Bluen and Barling, 1988). The linkage between work stress and industrial relations can be discussed in relation to three subareas. More specifically, inherent in the field of industrial relations is the conflict or potential conflict over domains of work control between labor and management. While labor and management may show a high degree of cooperation, such cooperation typically results from outside threat of competition or depletion of resources, rather than cessation of the basic conflict between labor and management (e.g. Kochan and Katz, 1988; Lawler and Mohrman, 1987). Clearly, such inherent conflict between labor and management may affect the level of stress and strain experienced by both managers and workers (Hartley, 1992). Yet, to date, very little research has focused on how labor-management relation actually contribute to individual stress and strain at work. Moreover, the industrial relations literature has recognized the unique position of union officials because they act as an interface among management, union and rank and file (e.g.

Business Service Location Strategies in the Barcelona Metropolitan Region

On the basis of two studies recently carried out on the supply and demand for business services, the fundamental aim of this article is to analyse business service location strategies in the Barcelona Metropolitan Region (BMR) and to demonstrate the existence of tendencies similar to those in other developed urban areas. Three conclusions clearly emerge: a growing and progressive externalisation of business services; the tendency towara's the urban concentration of these services, especially the most innovative and strategic ones; and the need for a high degree of co-operation between business service customers and suppliers.

Increasing Cooperation among Children Using Dependent Group-Oriented Reinforcement Contingencies

This investigation evaluated the differential effectiveness of two reinforcement contingencies for improving cooperation among students when solving a mathematics estimation task. The two reinforcement paradigms were a dependent group-oriented contingency and an individual reinforcement contingency. Subjects were 371 children enrolled in grades 2 through 5 at two public schools. The two schools were randomly assigned to the two reinforcement conditions. The estimation task required guessing the number of objects in a container on three occasions, at weekly intervals. Feedback (high, low, or correct) was provided each week. Results showed that the group reinforcement contingency resulted in superior estimation accuracy and was associated with a higher degree of cooperation among students. These findings were discussed within the context of the literature pertaining to group-oriented reinforcement contingencies for improving cooperation and academic skills.

Retinoid X receptor interacts with nuclear receptors in retinoic acid, thyroid hormone and vitamin D3 signalling.

Cellular responsiveness to retinoic acid and its metabolites is conferred through two structurally and pharmacologically distinct families of receptors: the retinoic acid receptors (RAR) and the retinoid X receptors (RXR). Here we report that the transcriptional activity of RAR and RXR can be reciprocally modulated by direct interactions between the two proteins. RAR and RXR have a high degree of cooperativity in binding to target DNA, consistent with previous reports indicating that the binding of either RAR or RXR to their cognate response elements is enhanced by factors present in nuclear extracts. RXR also interacts directly with and enhances the binding of nuclear receptors conferring responsiveness to vitamin D3 and thyroid hormone T3; the DNA-binding activities of these receptors are also stimulated by the presence of nuclear extracts. Together these data indicate that RXR has a central role in multiple hormonal signalling pathways.

College‐Corporate Cooperation: A Compelling Emerging Need

Competitive, technological and demographic imperatives are combining to dramatically change the nature of tomorrow’s workplace, and the needs of workers and managers comprising this workplace. To a significant extent, meeting the challenge of this change will involve educating and reeducating people, and will mandate a much higher degree of cooperation between academic and corporate education establishments. To achieve this cooperation, differences in perceptions, policies, and practices which have traditionally militated against cooperation among higher and corporate education establishments must be addressed, and strategic planning initiatives undertaken to develop cooperative programs and formats that best meet corporate education needs.

Stimulation of alanine metabolism by ammonia in the perfused rat liver. Quantitative analysis by means of a mathematical model

The effect of ammonia on the catabolism of alanine was studied in the perfused rat liver. Addition of 0.5 mM NH 4Cl to the perfusion medium containing 5 mM alanine plus 0.1 mM octanote produced drastic changes in the metabolite concentrations in the efflux medium. Not only the rate of ureogenesis was activated, but also the formation of glucose, lactate and pyruvate. Additionally, respiration was stimulated, the output of ketone bodies decreased, and the redox ratios lactate/pyruvate as well as 3-hydroxybutyrate/acetoacetate became more oxidized. To interpret the causes of these metabolic changes, a mathematical model was developed. It contains kinetic equations by which fluxes through essential pathways of alanine catabolism, gluconeogenesis and energy metabolism were related to the intracellular concentrations of pyruvate, oxaloacetate and ammonia, as well as to the redox ratios lactate/pyruvate and 3-hydroxybutyrate/acetoacetate. Using a nonlinear regression procedure, the model was suitable to be fitted to the data found in the experiments. The consistency of the model and experiment allowed the changes caused by ammonia to be explained. Primarily, ammonia stimulated ureogenesis hence accelerating the deamination of alanine which led to the increased formation of pyruvate, lactate and glucose. The enhanced energetic load resulting from ureogenesis and gluconeogenesis shifted the mitochondrial and cytosolic NAD systems towards more oxidized states which additionally modified the flux rates. The results demonstrate that there is a high degree of cooperativity between the metabolic pathways.

The enhanced ATPase activity of glutathione-substituted actin provides a quantitative approach to filament stabilization.

[Cys374]glutathionyl-actin was prepared by isolation of the reaction product of G-actin with Ellman's reagent (5,5'-dithiobis-(2-nitrobenzoic acid], followed by reaction with glutathione. Filaments of this actin disulfide are susceptible to even weak shearing stress as exerted, for example, by heating to 37 degrees C. This treatment produces a 25-fold enhanced steady-state ATPase activity as compared to unsubstituted F-actin at room temperature. Monitoring the reduction of this enhanced ATPase activity is a reliable method for quantifying the effectiveness of filament-stabilizing agents and for determining their apparent dissociation constants. A detailed comparative study of filament-stabilizing agents was performed, and some hitherto unknown filament-protecting effects were revealed. Inorganic phosphate provides stabilization only to a maximum of 45% ATPase inhibition, but reaches this effect already at cytoplasmic Pi concentrations (approximately 4 mM). Arsenate seems to bind with similar affinity, but with distinctly less protective activity (maximum of 16%). High concentrations of alkali ions provide a more effective protection (maximum of 95%), Li+ being more efficient than Na+ and K+. Divalent cations (Ca2+, Mg2+) had a strong stabilizing effect on KCl-polymerized actin; we confirmed the presence of two distinct classes of binding sites for divalent metal ions with moderate and low affinities, apparent in a strong stabilizing effect on KCl-polymerized actin. The stabilizing effects of KCl and Pi are independent and additive. Correspondingly, at K2HPO4 concentrations greater than 4 mM, K+ ions contribute considerably to stabilization. In the presence of 100 mM KCl plus 4 mM Pi, conditions which mimic the physiological environment, filament protection is nearly as effective as with the mushroom toxin phalloidin. The strong stabilizing effect of phalloidin occurred at concentrations far below stoichiometric, suggesting a very high degree of cooperativity in its interaction with actin filaments.

High Cooperativity, Specificity, and Multiplicity in the Protein Kinase C-Lipid Interaction

The number of phosphatidylserine molecules involved in activating protein kinase C was determined in a mixed micelle system where one monomer of protein kinase C binds to one detergent:lipid micelle of fixed composition. Unusually high cooperativity, specificity, and multiplicity in the protein kinase C-phospholipid interaction are demonstrated by examining the lipid dependence of enzymatic activity. The rates of autophosphorylation and substrate (histone) phosphorylation are specifically regulated by the phosphatidylserine content of the micelles. Hill coefficients of 8-11 were calculated for phosphatidylserine-dependent stimulation of enzyme activity, with a maximum occurring in micelles containing greater than or equal to 12 phosphatidylserine molecules. The high specificity that exists is illustrated by the fact that phosphatidylethanolamine and phosphatidylglycerol, but not phosphatidylcholine or phosphatidic acid, can replace only some of the phosphatidylserine molecules. We propose that Ca2+ and acidic phospholipids cause the protein to undergo a conformation change revealing multiple phosphatidylserine binding sites and resulting in the highly cooperative and specific interaction of protein kinase C with phosphatidylserine. Consistent with this, the proteolytic sensitivity of protein kinase C increases approximately 10-fold in the presence of phosphatidylserine and Ca2+ compared to Ca2+ alone. The high degree of cooperativity and specificity may provide a sensitive method for the physiological regulation of protein kinase C by phospholipid.

Divorce in the Kibbutz: Determinants of emotional adjustment

About two-thirds of a representative sample of kibbutz divorced subjects reached a satisfactory emotional and functioning level of adjustment with a high degree of cooperation between the exspouses by the second postseparation year. This outcome appears to be positively influenced both by a process of habituation and desensitization determined by the continuous physical proximity of the former spouses and by the neutralization of parenting and economic issues as subjects for dispute and litigation.

Two functionally distinct forms of guanosine cyclic 3',5'-phosphate stimulated cation channels in a bovine rod photoreceptor disk preparation

Cyclic nucleotide stimulated efflux of 22Na+ and 45Ca2+ from a purified bovine rod outer segment disk preparation was measured on the 25-100-ms time scale by a novel rapid superfusion method. Activation of cation efflux by 8-bromoguanosine cyclic 3',5'-phosphate (8-Br-cGMP) was maximal within 25 ms. Over a wide range of concentrations of 8-Br-cGMP, the kinetics of termination of efflux precisely conformed to the sum of two exponential decay processes: a rapid phase (decay constant of 200 ms) and a slower phase (decay constant of 1.6 s). The kinetics of the biphasic decay of efflux cannot be explained by depletion of a pool of releasable 22Na but appear to reflect an intrinsic process for inactivation of the channels. 8-Br-cGMP-stimulated release of actively accumulated 45Ca exhibited identical biphasic decay kinetics. The maximum rate of Ca release [5 nmol.(mg of disk protein)-1.min-1] may be sufficient to produce a 1 microM change in local cytoplasmic [Ca] within 20 ms. The Ca:Na selectivity ratio is approximately 0.5:1 for both decay phases. 8-Br-cGMP demonstrated a lower potency (EC50 of 8.4 microM vs 2.8 microM) but a higher degree of cooperativity in its activation of the rapid vs the slower decay phase of 22Na efflux. The slower phase of decay was selectively inhibited by 25 microM l-cis-diltiazem, a relatively weak inhibitor of the rapid decay phase. Sodium ion (5-10 mM) selectively inhibited the rapid decay phase of 8-Br-cGMP-stimulated 45Ca release. These two kinetically and pharmacologically distinct phases of decay are hypothesized to represent two functionally distinct forms of cGMP-stimulated cation channels.