Parallel Exchange Research Articles

Solution of dynamics of cis-bis(diphenylphosphino)ethene substituted derivatives of Ir 4(CO) 12

The fluxional behavior of [Ir 4(CO) 10( cis-Ph 2PCH=CHPPh 2)] ( I) and [Ir 4(CO) 8( cis-Ph 2PCH=CHPPh 2) 2] ( II) has been investigated by 13C and 31P NMR. Cluster I exists in solution as an equilibrium mixture of two geometrical isomers. Both isomers are fluxional due to two independent CO scrambling processes, and their interconversion is due to a slower P atom intramolecular migration from one metal centre to another. In contrast, the pairwise exchange of the P atoms in cluster II is not due to P atom migration but is the consequence of two parallel CO site exchange processes.

Foreign currency deposits and the demand for money in developing countries

This paper examines the relative demands for domestic and foreign currency deposits by residents of developing countries. A dynamic currency substitution model that incorporates forward-looking rational expectations is specified and estimated for a group of ten developing countries. The results indicate that the foreign rate of interest and the expected rate of depreciation of the parallel market exchange rate are important factors in the choice between holding domestic money or foreign currency deposits abroad. Furthermore, the model appears to fit the data better than a conventional partial-adjustment model.

Multiple Exchange Rates, Fiscal Deficits and Inflation Dynamics

The paper explores the inflationary implications of exchange rate regime reforms in a small open economy model combining the public finance view of inflation with multiple exchange markets. To account for the experience of many developing countries, the analysis focuses on transitions to multiple official exchange markets. In those countries, multiple exchange rates were often announced as temporary. The paper shows that the dynamic response of inflation to the reform markedly differ whether the announcement is credible or not. The paper also compares the response of inflation under a fixed crawl of nominal official rates and under the presence of policy rules aimed at reducing the spread between the official and parallel exchange rates.

Multiple Exchange Rates, Fiscal Deficits and Inflation Dynamics

The paper explores the inflationary implications of exchange rate regime reforms in a small open economy model combining the public finance view of inflation with multiple exchange markets. To account for the experience of many developing countries, the analysis focuses on transitions to multiple official exchange markets. In those countries, multiple exchange rates were often announced as temporary. The paper shows that the dynamic response of inflation to the reform markedly differ whether the announcement is credible or not. The paper also compares the response of inflation under a fixed crawl of nominal official rates and under the presence of policy rules aimed at reducing the spread between the official and parallel exchange rates.

Parallel Gibbs-ensemble simulations

A truly parallel algorithm for the Gibbs-ensemble simulation technique is given. The key components of this algorithm are a parallel displacement move based on the hybrid Monte Carlo method and a parallel exchange move based on a novel algorithm. For the parallel exchange move each processor generates additional trial conformations, and a trial conformation is selected with the most favourable energy. This introduces a bias, which is removed by a modification of the acceptance rules. A proof of the correctness of the parallel exchange move is given and the algorithm is verified for a Lennard-Jones system. Simulations on ten processors of an SP/2 parallel computer give a speedup of eight for large systems and a speedup of four for systems of typical size.

Exchange rate regime reforms with black market leakages

Many countries have multiple exchange rate regimes, with black or secondary currency markets operating alongside an exchange rate pegged or determined in interbank or auction markets. Leakages occur across these markets, necessitating careful analysis of the dynamic effects of numerous policy instruments. Using a model with multiple exchange rates and leakages, we trace the dynamic effects on official and parallel foreign exchange markets of exchange rate unification, changes in foreign exchange surrender requirements, taxes on trade and capital account transactions, and official exchange rate devaluation. Simulations based on Russia's recent experience demonstrate the qualitative importance of the results.

The Parallel Market for Foreign Exchange in an Oil Exporting Economy: The Case of Iran, 1978-1990

This paper provides a model for the determination of the parallel market exchange rate premium in a country where oil export earnings accrue directly to the government, and foreign exchange is centrally allocated for the importation of specific goods. Next, it studies the parallel market for foreign exchange in the Islamic Republic of Iran during the period 1978-90. The paper then examines the various time series properties of parallel market exchange rate in Iran, and the evidence of the role of oil and non-oil exports in the determination of the parallel market premium.

The Parallel Market for Foreign Exchange in an Oil Exporting Economy: The Case of Iran, 1978-1990

This paper provides a model for the determination of the parallel market exchange rate premium in a country where oil export earnings accrue directly to the government, and foreign exchange is centrally allocated for the importation of specific goods. Next, it studies the parallel market for foreign exchange In the Islamic Republic of Iran during the period 1978-90. The paper then examines the various time series properties of parallel market exchange rate in Iran, and the evidence of the role of oil and non-oil exports in the determination of the parallel market premium.

Loi de reponse d'un echangeur thermique soumis a des echelons de temperature aux entrees

In this paper we try to characterize the transient behaviour of parallel or counterflow heat exchangers when the two inlets are submitted at the same time to steps of temperature. The analysis lies on a two-parameter model for the temperature response, including a time lag tr and a time constant τ. By the mean of a time-dependent energy balance, we obtain an analytical expression of τ. Many special cases deduced from the general formulation are considered. This study is completed by a parametric analysis. Experimental investigations realized in various situations show a good agreement with theoretical results.

PARALLEL EXCHANGE RATES IN DEVELOPING COUNTRIES

Dual exchange rates and black markets for foreign exchange are common in developing countries, and a body of evidence is beginning to emerge on the effects that such parallel foreign exchange systems have on macroeconomic performance. This article presents a simple typology of parallel systems, discusses their emergence, and looks at why countries prefer these arrangements to the main alternatives. The article examines the ability of parallel markets to insulate international reserves and domestic prices from shocks to the balance of payments. Drawing on the findings from eight detailed case studies, the authors discuss the determination of the parallel premium in the short and long terms, the relationship between the premium and illegal transactions, and the fiscal effects of parallel rates. They compare the experiences of countries that have attempted to unify their foreign exchange markets and discuss the implications for policy alternatives.

Monetary shocks and exchange rate dynamics with informal currency markets

This paper examines the anticipatory dynamics associated with monetary policy shocks in an economy where an informal market for foreign exchange coexists with the official market. The analysis is based on a model with optimizing agents and currency substitution. It is shown that with certainty about the implementation date, a reduction in the nominal money stock leads to an appreciation in the parallel exchange rate upon announcement as well as during the transition period, followed by a subsequent depreciation. The direction of the initial jump in the parallel exchange rate upon announcement is, however, ambiguous under uncertainty.

Effects of extracellular bicarbonate ions and pH on volume-regulatory taurine efflux from rat cerebral cortical slices in vitro: evidence for separate neutral and anionic transport mechanisms

Net efflux of [ 3H]taurine from cells in pre-loaded slices of rat cerebral cortex has previously been shown to occur via an anionic pathway, believed to consist of exchange of anionic taurine for extracellular Cl −, and operating under both isomotic and hypoosmotic conditions, and a calmodulin-dependent mechanism, activated by hypoosmotic stress: the latter may comprise conductive channels (Law, R.O. (1994) Biochim. Biophys. Acta 1221, 21–28). Experiments have now been performed to examine two inter-related problems; firstly, how anion/anion exchange (assuming 1:1 stochiometry) could contribute to the regulation of brain cell volume, and secondly, whether the hypoosmotically-activated component of efflux represents a second anionic transport process or loss of neutral taurine. The former process has been shown to be strongly dependent upon extracellular pH and bicarbonate concentration, being accelerated by low pH (7.0) and high (60 mmol/1) bicarbonate, and retarded by alkalinization (pH 7.8) and low (2.5 mmol/l) bicarbonate. Taurine efflux is inhibited by acetazolamide, with accompanying cell swelling in both isoosmotic and hypoosmotic media. It is hypothesized that inwardly directed bicarbonate transport, in exchange for intracellular Cl −, operates in parallel with efflux of anionic taurine in exchange for extracellular Cl −, and it is the subsequent conversion of bicarbonate to CO 2 and water, under the influence of carbonic anhydrase, that effects a volume-regulatory decrease in internal osmotic potential. The dependence of taurine efflux upon pH and bicarbonate persists in the presence of trifluoperazine (an inhibitor of calmodulin activation) but is abolished in hypoosmotic media by the anion transport inhibitor niflumic acid. Cell depolarization in high K + has no effect on taurine efflux, which is envisaged as involving parallel electroneutral anion exchange processes (taurine/Cl − and Cl −/bicarbonate) augmented, in hypoosmotic media, by diffusive efflux of neutral taurine.

Closing the Hong Kong Gap: the Hong Kong free dollar market in the 1950s

In the last io years parallel foreign exchange markets have generated considerable interest among economists in the context of developing countries.2 The imposition of foreign exchange and trade controls to foster economic development in these countries has commonly generated parallel exchange markets, whether black, legal, or informally tolerated. The current research has focused on various aspects of these free markets such as the effect on domestic price stability,3 the effect of devaluation,4 and the impact of the markets on the effectiveness of macroeconomic policy.5 One important feature which has attracted much less interest is why parallel currency markets were tolerated.6 A proper investigation of official motives is important as it permits a better analysis of the thinking that underpinned policy at the time-of the perceived advantages and disadvantages for the economy in general as well as for the monetary authority or government in particular.7 The literature has focused on negative aspects of parallel exchange markets and concluded that a major reason for allowing them to operate is that they are prohibitively expensive to eliminate. McDermott, however, has suggested some positive economic aspects of black markets in foreign exchange for developing countries.8 He argues that, in theory, parallel exchange markets may actually increase foreign exchange earnings and increase employment by allowing a greater volume of imports for export industries than could be allocated from the official reserves. This model depends on a high import content of exports which is often associated with developing countries. It is the purpose of this article to pursue an explanation for the UK toleration of the Hong Kong parallel exchange market in the I950S and to suggest implications of the market for the development of the Hong Kong economy. An historical perspective on parallel exchange markets is lacking

Unification of Foreign Exchange Markets: A Comment on Agenor and Flood

Recently in an interesting paper in IMF Staff Papers, Pierre-Richard Agenor and Robert Flood (1992) set up a theoretical model of dual exchange rates and analyzed how the economy would work given the shock of an announcement to unify dual exchange markets. Provided that the unified exchange rate under the flexible regime is greater than the official exchange rate under the dual regime, their major findings are (i) at the announcement, the domestic price of foreign currency in the parallel exchange market depreciates immediately, (ii) the parallel exchange rate keeps rising and net foreign assets keep falling during the pre-unification period, and (iii) the unified exchange rate of the post-unification regime is independent of the timing of unified implementation. This paper is written for two purposes. First, we intend to show that the unified exchange rate of the post-reform regime is inversely related to the date of reform. Second, we attempt to extend the graphical presentation of Agenor and Flood (1992) and to trace the possible dynamic behavior of relevant variables during the unified process.1

Regulation of NaCl entry into Necturus gallbladder epithelium by protein kinase C.

The role of protein kinase C in the regulation of the mode of NaCl entry into Necturus gallbladder epithelial cells was determined from the rate and magnitude of ouabain-induced cell swelling in the presence of inhibitors. Stimulation of protein kinase C by phorbol ester increased the rate of cell swelling from the control value of 2.9% to 4.7%/min and caused the predominant apical membrane transport mechanism for NaCl to switch from bumetanide-sensitive Na-Cl cotransport to amiloride-sensitive parallel exchange. Na-Cl cotransport could be restored as the predominant mode of NaCl entry by treatment of stimulated tissues with the kinase inhibitors 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7) and calphostin C. Therefore the mechanism of NaCl transport across the apical membrane can be controlled by the activity of protein kinase C.

Molecular propane adsorption dynamics on Pt(110)−(1 × 2)

The molecular adsorption probability of propane on clean and propane-covered Pt(110)-(l × 2) was measured as a function of incident translational energy, E i, incident polar angle, θ i, propane surface coverage, θ cov, and azimuthal angle at a surface temperature of 95 K. The dependence of the adsorption probability on E i, and θ i at all propane coverages reflects significant participation of parallel momentum in the adsorption process due to corrugation in the propane/Pt(110)-(1 × 2) interaction. When the tangential velocity component of the molecular beam is directed along the close-packed atomic rows (the [11̄0] direction), the initial adsorption probability increases with increasing θ i; however, the initial adsorption probability decreases with θ i, when the crystal azimuthal angle is rotated 90°, indicating parallel momentum exchange dominates the adsorption process on this azimuth. Adsorbed propane facilitates trapping; S 0 increases linearly with propane coverage up to 0.55 saturation coverage. As θ cov increases, corrugation in the adsorbed layer dominates the adsorption process for all angles of incidence, and the azimuthal dependence of the adsorption probability becomes negligible except at the most glancing angles of incidence. A sudden change in the coverage dependence of the adsorption probability is observed at surface coverages above 0.55 saturation coverage.

Transient behaviour of shell and tube heat exchangers

AbstractBased on the dispersion model rather than on the conventional pluf‐flow model, a method of predicting the transient behaviour of parallel and counterflow heat exchangers is developed, whereby the effects of shell‐side flow maldistribution and the finite heat capacities of both fluids, tube bundle and shell are considered. The final solution has been obtained by numerical inversion of the Laplace transform, to determine the transient responses to arbitrary inlet temperature variations. The experiment was carried out in a one pass tube heat exchanger. The comparison between therotical and experimental results is presented and the feasibility of this method is discussed.

The causality between official and parallel exchange rates in developing countries

The paper examines the causal relationship between official and parallel exchange rates in developing countries, using a methodological approach based on the statistical theory of cointegration and Granger-causality tests. The application of the procedure to monthly data covering a 13-year period for 19 countries suggests no clear causality pattern across countries

Improving the Accuracy of the Low-Order Models for Heat Exchangers

For both counter current and parallel heat exchangers, the transfer functions from the partial differential equations are simplified. The accuracy of these low-order models can be increased through a step-by-step procedure. For counter current heat exchangers, this is done by taking more terms from the Taylor expansion of some specific terms in the transfer functions. For parallel. heat exchangers, a new model, which is called the sectionally-distributed model, is proposed. The accuracy of these low-order models are compared with their original transfer functions in the frequency domain and with the high-order lumped models in the time domain.

Consumption and significance: The shape of things to come

Our necessary involvement in the everyday traffic of mass-produced goods and services also immerses us in a parallel exchange of symbolic understanding. From this basis, it is argued that the various landscapes which accommodate the consumption of these artefacts are themselves parts of the social and symbolic structures we create and maintain through such trade. Accordingly, a semiological analysis of goods from major industrial cultures like Britain, Japan and the USA shows how consumers of these goods are obliged to accept the limitations and the inequalities of a social and symbolic order which admits that, physically and intellectually, some of its members may render the world as artefacts while the next can only shape their lives by trading in these terms.