Showing papers by "University College Dublin published in 1982"

Booming Sector and De-Industrialisation in a Small Open Economy

Abstract: This paper presents a theoretical analysis of the 'Dutch Disease': the phenomenon whereby a boom in one traded goods sector squeezes porfitability in other traded goods sectors, both by directly bi ...

Periodic replacement when minimal repair costs vary with time

Abstract: A policy of periodic replacement with minimal repair at failure is considered for a complex system. Under such a policy the system is replaced at multiples of some period T while minimal repair is performed at any intervening system failures. The cost of a minimal repair to the system is assumed to be a nonde-creasing function of its age. A simple expression is derived for the expected minimal repair cost in an interval in terms of the cost function and the failure rate of the system. Necessary and sufficient conditions for the existence of an optimal replacement interval are exhibited in the case where the system life distribution is strictly increasing failure rate (IFR).

Ground-state configurations of ionic species I through XVI for Z = 57 − 74 and the interpretation of 4 d − 4 f emission resonances in laser-produced plasmas

Abstract: Spectra of the elements barium ($Z=56$) through Nd ($Z=60$) observed in laser-produced plasmas from pure-metal targets in the wavelength region 70- 130 \AA{} are presented. This completes our survey of the spectra of elements from cesium to hafnium in two regimes of optical thickness. The two sets of spectra show significant differences. In order to interpret the whole range of results, we need to know the ground-state configurations of ions in stages up to XVI for $Z=55\ensuremath{-}71$. From the limited-term analyses available, a table of plausible ground configurations is proposed. In the preparation of the table, the effect of increasing ionization, for a fixed $Z$, on wave-function contraction is studied, and it is inferred that the $4f$ electron becomes more tightly bound than $5p$ between the sixth and seventh spectra of the elements from cerium to lutetium; similarly the $4f$ electron attains a higher binding energy than does the $5s$ between the fourteenth and fifteenth spectra. Consequently, for a considerable range of ion stages, particularly in the rare earths, the ground configurations have a partially filled $4f$ shell. Furthermore, in the same ion stages, the $4f$, $5p$, and $5s$ energies stay relatively close together so that configurations of the type $5{p}^{l}4{f}^{n\ensuremath{-}l}$ lie very near the nominal ground configuration. A corresponding manifold of overlapping excited configurations of the type $4{d}^{9}4{f}^{n+1}$, $4{d}^{9}5{p}^{l}4{f}^{n\ensuremath{-}l+1}$ is also expected and the observed resonances arise from all of the $4d\ensuremath{-}4f$ transitions permitted between the upper and lower manifolds of configurations. The numbers of transitions are calculated and in the majority of cases are very great. Because the principal quantum number does not change, the transitions will tend to overlap for different ion stages of any one element. The widths and varying complexity of the resonances can be explained in a satisfactory, if qualitative, way by means of available theory. The very considerable difference between the compound and metal spectra can be explained in terms of the effect of number density of the active species on both emission and absorption processes in the two types of plasma.

Sectoral Shocks in a Dependent Economy: Long-run Adjustment and Short-run Accommodation

Abstract: This paper examines the allocation and stabilization consequences of a resource boom in a small open economy. Both the intersectoral allocation of capital and the price of non-traded goods adjust sluggishly; in contrast the nominal exchange rate adjusts instantaneously to ensure that the conditions for uncovered interest parity in the presence of rational exchange rate expectations are always met. The ability of monetary policy to stabilize the economy is examined, and it is shown that, even when intervention is justified in principle, policy errors which arise from confusing real and monetary shocks may worsen macroeconomic performance.

The regulation of pyocyanin production in Pseudomonas aeruginosa

Abstract: Pyocyanin was produced only after the exponential phase of growth on all media examined. Pyocyanin was also found to be produced in response to some nutrient limitation (for example, carbon or oxygen). Furthermore, by controlling the growth rate at less than approximately 0.1 h−1 the repression of pyocyanin production could be overcome to a large degree. An inverse relationship existed at low growth rates between growth rate and pyocyanin production, with a decrease in growth rate resulting in increased pyocyanin levels. Therefore, pyocyanin production appeared to be regulated by the energy status of the cell which would be lowered under conditions of low nutrient concentration, resulting in a decrease in growth rate and an increase in the level of pyocyanin produced. Under conditions of readily available nutrients the energy generating capacity of the cell was increased resulting in an increased growth rate and repression of pyocyanin. The ability of uncouplers of oxidative phosphorylation (e.g. CCCP and FCCP) to induce pyocyanin production, and of inhibitors of the membrane-bound ATPase (e.g. DCCD and sodium azide) to repress pyocyanin production, confirmed the existance of an energy mediated regulatory mechanism. Indeed, the evidence presented here along with the reported regulatory role of inorganic phosphate in pyocyanin production, suggests that production of this antibiotic may be regulated by intracellular ATP levels.

The development and questing activity of Ixodes ricinus (L.) (Acari: Ixodidae) under field conditions in Ireland

Abstract: Development rates of engorged examples of Ixodes ricinus (L.) and the onset and duration of questing activity of unfed ticks were investigated in gauze cages in the field in the Irish Republic. Development rates of the various stages were broadly similar to those described in other studies but differed in small detail from most of them. It was found that larvae that fed during or after the first two weeks of August entered diapause. The activity periods of questing ticks were found to agree closely with observations made in the field, and the origins of the various peaks in tick activity in the field were thus elucidated. It was established that considerable interchange between autumn-feeding and spring-feeding populations of ticks can occur, and it is concluded that the extent of this is largely controlled by the weather, being accentuated by high summer temperatures.

Effects of tranexamic acid on the coagulation and fibrinolytic systems in pregnancy complicated by placental bleeding.

Abstract: Treatment with the fibrinolytic inhibitor tranexamic acid was investigated in 12 women with vaginal bleeding in the second half of pregnancy. The aim of the therapy was to accelerate haemostasis in the uteroplacental circulation and to prevent further bleeding at the placental site. Tranexamic acid 1 g 8-hourly was given for 7 days. Serial investigations of coagulation and fibrinolysis were carried out. Plasma fibrinolytic activity, plasminogen, antiplasmin and platelet count significantly decreased during treatment, while antithrombin III and factor VIII related antigen showed a significant increase. Plasma tranexamic acid levels ranged from 5 mg/1 to 17 mg/1. Two patients on treatment at the time of delivery had plasma tranexamic acid levels of 9 mg/1 and 12 mg/1 detected in the umbilical cord venous blood. No adverse effects were detected in any of the mothers and all 12 were delivered of live born infants. Tranexamic acid may have a therapeutic role in accelerating haemostasis in the uteroplacental circulation and thereby reducing the adverse effects of bleeding at the placental site.

Epidemic hepatitis B with delta-antigenaemia among Dublin drug-abusers.

Abstract: ONE hundred and fifty-eight cases of hepatitis have been detected among Dublin drug-abusers from January to August 1981 during an epidemic which originated in 1980 and still continues. The mean age was 21 years and the male/female susceptibility to hepatitis was the same. An unusually high proportion (29%) of a sample of 50 tested had the hepatitis associated delta antigen in their serum and confirms that the delta agent is probably common in drug addicts and not confined to Italy.

Behavioural responses of the carrot fly larva, Psila rosae, to carrot root volatiles

Abstract: . The behaviour of the carrot fly larva, Psila rosae F. (Diptera, Psilidae), was investigated in the presence of six concentrations of thirty-four volatiles associated with carrot root and of trans-methyl-iso-eugenol, a constituent of carrot herb oil. Bomyl acetate, 2,4-dimethyl styrene, α-ionone, SbT-ionone and biphenyl were the most consistently preferred compounds. Klinotaxis and klinokinesis were the orientation responses near the stimulus source. Trans-2-nonenal was the most consistently avoided compound. Extracts derived by steam distillation of carrot roots and by concentration of vapour from roots were resolved, by gas liquid chromatography, into forty-five and twenty-two major constituents, respectively. The five preferred compounds are micro-components of these extracts, collectively representing 1% and 0.6% of root extract oil and vapour, respectively. It is suggested that these secondary plant constituents are specific host finding cues for the larva, and that frara-2-nonenal is a carrot defence compound.

The demonstration of protein-bound 99Mo-di- and trithiomolybdate in sheep plasma after the infusion of 99M0-labelled molybdate into the rumen.

Abstract: 1. Protein-bound, trichloroacetic acid- (TCA) insoluble 99 Mo appeared in plasma a few hours after the introduction of 99 Mo-labelled molybdate (30 mg Mo) into the rumen of sheep maintained on a basic diet supplemented with elemental sulphur (3 g S/d). 2. Most of the 99 Mo could be displaced from its protein carrier in vitro and the labelled compounds displaced were identified by Sephadex G-25 chromatography as di- and trithiomolybdate. Tetrathiomolybdate was not detected. 3. In control experiments protein-bound, TCA-insoluble 99 Mo predominated in plasma after the direct administration of [ 99 Mo]tetrathiomolybdate, either into the rumen or intravenously. The 99 Mo could be displaced in vitro and [ 99 Mo]tetrathiomolybdate identified, although [ 99 Mo]trithiomolybdate was also present.The study provides direct evidence of thiomolybdate synthesis and absorption in ruminants in vivo.

Photolysis of carbon tetrachloride in the presence of alkanes

Abstract: The photolysis of carbon tetrachloride in the presence of a number of alkanes has been investigated in the gas phase. The products obtained from the photolysis experiments were those expected from a chain reaction in which trichloromethyl radicals abstract hydrogen atoms from the alkane. The data have been used to determine Arrhenius parameters for hydrogen abstraction from the series of alkanes CH4, C2H6, C3H8, and i-C4H10 by trichloromethyl radicals, The rate data obtained are used to explain why termination reactions involving alkyl radicals become less significant as the alkane becomes more complex.

Demographic determinants of perceived well-being in eight European countries

Abstract: This paper reports results of a harmonised study of subjective social indicators carried out in eight member countries of the European Community, sponsored, on an experimental basis, by the Statistical Office of the European Communities (Luxembourg). Comparative data from nationwide representative samples from Germany, France, Italy, the Netherlands, Belgium, the United Kingdom, Ireland and Denmark are presented for three key dependent measures of perceived well-being: Self-Assessed Health, Satisfaction with Housing and Life Satisfaction. The cross-cultural generalisability of the influence of demographic variables on these three measures in examined, using 4-way analysis of variance. The analyses revealed a remarkable consistency across nations in terms of the effects of certain demographic variables on some of the dependent measures; however, some inconsistencies were also revealed. Substantial discrepancies in mean scores of the same sub-groups in different countries were also observed. While further research would be required to determine whether these differences were due to objective circumstances or to cultural differences in subjective perceptions or response patterns, some tentative interpretations of the differences were put forth.

The development of a sampling method for the tick Ixodes ricinus and its use in a redwater fever area

Abstract: SUMMARY Tick sampling methods based on blanket dragging and flagging were assessed with a view to carrying out a tick survey in an area of endemic babesiosis. The strip-flag method was finally selected for its efficiency, consistency, and practicality. This method was used to sample larval tick populations on ten farms with endemic babesiosis and it was found that these farms harboured very low densities of ticks compared with a control site. Possible explanations for this finding are discussed.

Spectral-irradiance calibration of continuum emitted from rare-earth plasmas

Abstract: The spectral irradiance of laser-produced plasmas of gadolinium and ytterbium have been determined in the 115-220-nm range for an incident 2.2-J, 30-nsec ruby-laser pulse. The effects of target geometry arnd variation of laser energy on the spectral irradiance were also studied. The potential of the source as a radiometric standard is discussed.

Local Anaesthetics Including Benzyl Alcohol Activate the Adenylate Cyclase in Trypanosoma brucei by a Calcium-Dependent Mechanism

Abstract: 1 The adenylate cyclase of Trypanosoma brucei is activated by local anaesthetics. 2 Activation of adenylate cyclase by the local anaesthetic, benzyl alcohol, requires Ca2+. 3 The kinetics of the presteady state reveal that the activation step occurs prior to and is separate from the catalytic step. 4 The activation step in the presence of Ca2+ can be stimulated some 200-fold and is highly co-operative with respect to benzyl alcohol concentration. 5 The mechanism by which local anaesthetics activate may be by exposing the Ca2+-binding site of the catalytic step. Ca2+ receptor which is oriented towards the hydrophobic regions of the plasma membrane in the basal state.

An intelligent terminal for implementing relevance feedback on large operational retrieval systems

Abstract: Research has shown that document retrieval based on weighting functions and incorporating relevance feedback may be more effective than retrieval based on Boolean combinations. These novel methods have not been adopted by the large operational systems. In this paper, a software implementation of an 'intelligent terminal' is described. It overcomes many of the objections to non-Boolean retrieval. It is linked to an operational database via EURONET, and includes such features as the weighting of search terms, the construction and submission of search statements in the Common Command Language of EURONET, and the use of relevance feedback information to improve retrieval.

Response of wheat and barley isolates of Septoria nodorum to passage through barley and wheat cultivars

Abstract: A single-spore wheat isolate of S. nodorum was passaged once through barley and a barley isolate passaged once through wheat. Reisolations from barley leaves were designated as either ‘original-type wheat’ (OTW) and resembled the wheat isolate used for inoculations in morphology, or ‘sector-type barley’ (STB) resembling the known morphology of barley isolates. Reisolations from wheat were similarly designated either OTB or STW. Sub-cultures of STB were significantly more pathogenic to barley in a glasshouse experiment than OTW, and vice versa. Similarly STW was significantly more pathogenic to wheat than OTB, and vice versa. A single-spore wheat isolate was also passaged 0, 1, 2, 3 or 4 times through barley and a barley isolate passaged similarly through wheat. Disease assessment and yield data from a field experiment showed that the pathogenicity of the passaged wheat isolate remained largely unaltered from that of the original isolate. However, the barley isolate responded after the third wheat passage by causing significantly less disease and significantly higher yields in barley than the unpassaged isolate; conversely, on wheat, disease levels significantly increased and yield slgnficantly decreased after the second wheat passage. Data obtained are discussed in the context of cultural observations made on colony morphology during host passage sequences and possible genetic mechanisms responsible.