Actions Of Other Agents Research Articles

The effect of glucose on chloride uptake by Chlorella

Glucose at 5 mM inhibited chloride uptake by Chlorella fusca in the light and in the dark by 30±10% and acidified the cell interior by 0.2 units (measured with 5.5-dimethyl-oxazolidine-2.4-dione; DMO). Neither effect was shown by the glucose analogues 3-O-methylglucose and 6-desoxyglucose which are transported into the cell but not metabolized. As it was surmised that inhibition of Cl(-) transport was the result of intracellular acidification, the action of other agents on Cl(-) transport and intracellular pH was examined. The Tris salts of the permeant acids DMO and propionic acid inhibited Cl(-) transport. The concentration and pH dependence of this effect were consistent with the free acids being the effective agents. At pH 6.7 the 15 mM Tris salts has about the same effect on Cl(-) transport as 5 mM glucose. Under these conditions the intracellular pH (measured by the DMO method) was lowered by 0.2 units with glucose as well as, in presence of the Tris salts. When the algae were gassed with 1.5% CO2 in air, Cl(-) uptake in the light was depressed to 40-50% and the intracellular pH was lowered by 0.4 units. On the basis of these observations and the results from the preceding study, inhibition of Cl(-) transport by glucose is interpreted as inhibition of an ATP-dependent Cl(-)/OH(-) exchange by intracellular acidification, due to glucose metabolism.

Moral Hazard, Agency Costs, and Asset Prices in a Competitive Equilibrium

The behavior of economic agents in the presence of uncertainty about exogenous events and imperfect information about the endogenously influenced actions of other agents with whom they contract has been receiving growing attention. In particular, the economic theory of agency explicitly recognizes that when agents enter into synergistic relationships, each agent will act in a manner consistent with the maximization of its personal welfare, thus giving rise to a phenomenon called moral hazard. Harris and Raviv [8], Holmstrom [10], and Shavell [21] have analyzed the nature of Pareto-optimal contractual mechanisms designed to ameliorate moral hazard and achieve efficient risk sharing. Jensen and Meckling [12], Grossman and Hart [6], and Thakor and Gorman [22] have explored the impact of moral hazard on the capital structure decisions of firms. Arrow [1] explained the absence of complete contingent claims markets on the basis of moral hazard, and Harris and Raviv [7] have examined the impact of moral hazard on the structure of health insurance contracts.

An Introduction to the Theory of Rational Expectations Under Asymmetric Information

Every good economics textbook contains the cliche that market prices provide signals which facilitate the allocation of resources to their best use. In a world not subject to random shocks, consumers and producers when faced with competitive prices need look no further than their own preferences or production technology to be able to make a decision. They need give no thought to the tastes, endowments or technology of other agents. However, in a world subject to random shocks, this is no longer the case. Agents are faced with the problem of forecasting future states of nature and more importantly of forecasting the impact of these states on the actions of other agents. Rational expectations theories provide a model of how agents make those forecasts. In a world subject to random shocks, it will be the case that agents acquire (or at least attempt to acquire) information about the future realization of the shocks. It will, in general, be the case that different agents have access to different information. The fact that information is dispersed throughout the economy has the potential to cause a misallocation of resources relative to what would be the case if all agents knew everything. An efficient allocation of resources will in general require the transfer of information from consumers who have some information about their future demands to producers who can take current actions to mitigate avoidable scarcities or surpluses. Though many classical and neo-classical writers emphasize the informational role of prices, the standard Marshallian or Walrasian model of competitive equilibrium does not involve prices transferring information across traders. The purpose of this paper is to show that rational expectations models are radically different from Walrasian models in an economy where traders have diverse information. This is demonstrated by showing that unlike what occurs in a Walrasian equilibrium of an economy with heterogeneous information, if there is a complete set of insurance markets and utility is additively separable over time, then there exists a rational expectations equilibrium which gives consumers the same allocation as if each consumer has access to all of the economy's information. This implies that, under the above assumptions, a central planner with all the economy's information could not Pareto dominate the competitive allocation achieved when traders have diverse information and rational expectations. This paper makes no attempt to survey the literature on rational expectations. The reader is referred to Shiller (1978), Barro (1981) for a survey of macroeconomics and rational expectations, and Radner (1980) for a survey of the microeconomics and mathematical theory of rational expectations. This paper will, however, try to outline the evolution of the rational expectations concept from a notion of optimal forecasting to a virtually complete departure from the Walrasian model of equilibrium. The rest of this section is devoted to a discussion of pre-rational expectations ideas.

Characteristics of prostaglandin E 1 potentiation of inflammatory activity of some agents

In rats pretreated with indomethacin, injection of PGE 1 (prostaglandin E 1) with carrageenan potentiated the carrageenan paw oedema. This effect of PGE 1, was maximal when it was injected together with carrageenan, there being a reduction in the action of PGE 1 if carrageenan injection was delayed after PGE 1 injection. PGE 1 induced potentiation of increase in plasma protein leakage induced by intradermal injections of bradykinin and histamine also depended on the injection of PGE 1 along with these agents. Thus oedema enhancement by PGE 1 differs from its action in pain, where PGs cause a long lasting sensitization of the injected area for the actions of other algesics. Since vasodilation may be a mechanism of oedema enhancement by PGs, the ability of adenosine and papaverine to mimic PGE 1 in paws and skins of rats were examined. Adenosine was active whereas papaverine was inactive in this respect. To clarify this difference, the vasodilatory properties of PGE 1, adenosine and papaverine were assessed by their ability to antagonize NA response in perfused rat mesenteric blood vessels. Only papaverine was effective in antagonising the NA response. Thus, PGE 1 and adenosine which potentiated the oedema inducing actions of other agents showed no vasodilatory properties and papaverine, a vasodilator, had no oedema potentiating actions.

Unemployment Equilibrium with Myopic Complete Information

We will demonstrate that unemployment equilibrium can arise (even at Walrasian equilibrium prices) when each non-cooperative optimizing agent has full information about the consequences of his actions.' Agents may be unable to trade all they wish at going market prices because of insufficient demand for goods they want to sell (or insufficient supply for goods they wish to buy). Both in and out of equilibrium, each agent is assumed to know the actual trade possibilities open to him, conditional upon the actions of other agents remaining constant. This degree of information will be called myopic complete information.' Our interest in endowing agents with this much information is that unemployment is less surprising when agents have pessimistic expectations about their trading possibilities. Unemployment in this paper is not due to underestimates (by firms) of demand for output, nor does the presence of unemployment depend on underestimation (by workers) of income. We make the polar assumption that quantities rather than prices adjust when a market does not clear. Later on, we argue that for some plausible disequilibrium dynamics, there is no pressure on prices at some equilibria. We also exhibit examples of unemployment equilibrium at Walrasian equilibrium prices. Thus, unemployment is not merely the result of rigid prices set at the wrong levels. Studies of unemployment equilibrium face a persistent difficulty in specifying the character of individual optimization. The sticky points include (i) whether quantity constraints on individual purchases and sales implied by the failure of markets to clear are taken as rigid or subject to manipulation by agents' actions; (ii) whether the quantity constraints and the more conventional budget and non-negativity constraints apply to agents' offers (which may not be fulfilled) or to realized trades; (iii) whether offers (which may not be realized) to trade a commodity represent an optimization with respect to that commodity alone (a partial disequilibrium calculation) or an optimization with respect to all goods (general disequilibrium). The view we take in the present study is that budget and nonnegativity constraints apply directly only to actual trades, not to offers. Agents in the market have a rather good idea of what trade will be realized from offers they make. Offers are made after calculation with respect to all markets at once. That is, an offer for a good is made in light of other offers for its substitutes, complements, and other goods (if any) related to it through preferences or the allocation mechanism. Several authors have demonstrated the existence of unemployment equilibrium in a decentralized economy with optimizing agents (Glustoff (1968), Benassy (1975), Dreze (1975), Grandmont-Laroque (1976), and Hahn (1978)). Walrasian equilibrium with

Facilitation by imidazole of the aqueous flare response toα-melanocyte stimulating hormone

MSH, like traumata to the eye, cause a permeability disturbance in rabbits, with protein leakage into the aqueous. The MSH effect was enormously increased by instillation of imidazole or pilocarpine. The MSH effect seems to engage a different mechanism than the prostaglandin-dependent action of other agents.

DYNAMICS OF α‐ADRENERGIC INHIBITION OF THE ADENYL CYCLASE—CYCLIC AMP SYSTEM IN HUMAN ADIPOSE TISSUE

In short-term incubations of fat cells isolated from human adipose tissue, noradrenaline (0.2-2x10--5 M), a mixed alpha and beta-adrenergic agonist, stimulated only slightly cyclic AMP accumulation. In the presence of the alpha-adrenergic blocking agent phentolamine (0.05-5mug/ml), noradrenaline markedly augmented the amount of labelled cyclic nucleotide. The stiumlatory effect of noradrenaline and noradrenaline plus phentolamine was abolished by propranolol (0.1-10 mug/ml). Theophylline (10--4-10--3 M) slightly increased the (3-H) cyclic AMP levels per se and magnified the stiumulatory action of other agents, but did not mimic the potentiating effect of phentolamine on noradrenaline action.

David Lyons on utilitarian generalization

We have now examined two versions of UG — that proposed by David Lyons, and a new version derived from his. Both were found to be extensionally nonequivalent to AU, but both were also found to be unacceptable moral theories (Lyons' version generated counter-intuitive prescriptions, and the derived version failed to generate any prescriptions at all in an important range of cases). Naturally, these results cannot be taken to show that no satisfactory form of UG will be forthcoming. But at least some of the conditions to be met by future proposals are now clear: any successful version of the theory must interpret the ‘generalized performance’ of an action to include only the actions of agents who face similar ranges of alternatives, and (in some cases) must select as relevant a description of the action which does not refer, either explicitly or implicitly, to the actions of other agents. Reflection shows that the same remarks hold true, mutatis mutandis, for rule utilitarianism as well: unless the rules are formulated with extreme care in these respects, they may yield unacceptable recommendations, or else fail to recommend any action at all in the very cases they are designed to resolve.17

Strychnine Tetanus and the Mechanism of Neuronal Synchronization.

Oscillographic study indicates that spinal strychnine tetanus is the most perfect expression of the synergy of elementary electrical activities in a mass of nerve cells. Strychnine tetanus was studied in the curarized cat under light dial anesthesia (10 to 20 mg per kg) with the special purpose of analyzing the mechanism of neuronal synchronization. The following facts were demonstrated: 1. Tetanic waves, recorded from any segmental level of the spinal cord by means of an active electrode thrust into the grey matter of the anterior horn, have regularity of form, amplitude and rhythm of an alternating current. Their frequency varies from 30 to 10 per second, their voltage from 500 to 100 microvolts. Usually there is an inverse relationship between voltage and frequency. This relationship becomes most apparent when the frequency of the tetanic waves has been increased as the result of an intravenous injection of nicotine. 2. With each tetanic wave there is a corresponding strong discharge of centrifugal action potentials in the anterior roots. This discharge begins with the rising phase of the tetanic wave and is maximal at its peak. 3. Cell groups of the posterior horns do not participate in the strychnine tetanus. They are likewise refractory to the synchronizing action of other agents. 4. Waves simultaneously recorded from cervical, dorsal and lumbosacral regions of the cord are practically synchronous. They are never out of phase by more than 3 milliseconds. 5. This synergy cannot be explained by synaptic transmission of intraspinal impulses from a focus playing the rôle of a pacemaker, for the following reasons: (a) The cervical and lumbar reflex waves produced by stimulation of a posterior lumbar root (break shocks) are separated by a time interval which is never less than 8 milliseconds even if the spinal cord is strongly strychninized with a just subtetanic dose. (b) Strychnine tetanus is abolished by depressor agents (ether anesthesia for 30 seconds; anelectrotonus) at doses or intensities which do not affect, or only slightly diminish the amplitudes of spinal reflex waves. Conversely, a strong tetanus may continue in the absence of all electrically demonstrable reflex activity in the intervals between tetanic discharges. (c) Synchronization of the tetanic waves produced by two adjacent spinal segments may persist after complete separation of the segments by spinal transection.

EFFECTS OF DRUGS ON THE STRIA VASCULARIS

The clinical literature dealing with drugs known to cause impairment of hearing has recently been reviewed by Taylor. 1 The length of the list of substances affecting hearing is as appalling as the diversity of their natures. An experimental approach to the problem will prove fruitless unless studies on a few of these agents are made from various angles. Histologic changes in the peripheral auditory mechanism, as well as lesions which might be apparent in the central auditory pathways, when correlated with the results of hearing tests on animals should finally aid in a better understanding of the action of such drugs as quinine. Once it is possible to find and evaluate these changes in terms of the animal's ability to hear, the action of other agents can be more readily determined. It is not impossible to examine microscopically a section through the cochlea and ascertain the degree to which the