Copper Supply Research Articles

Nouvelles propositions de classement des monnaies de « bronze » de Claude Ier

Summary. — The profusion of bronze coins minted under Claudius has long puzzled historians and numismatists. The great stylistic variety of coins of this type would appear to preclude any satisfactory classification. On the basis of the material uncovered in Armorie ford deposits at Saint-Léonard (Jublains, Mayenne) and in Vilaine (Rennes, Ille-et- Vilaine), we here propose a new method of classification with the strict division of official and imitation coins. Various Methods of elementary analysis are used to confirm the accuracy of categories obtained by other criteria (style, epigraphy, flan shape, die axis and the geographic distribution of discoveries). The results appear to show that, concurrent with purely local striking (illicit mints) and the output of the official mint in Rome, several official mints located in Gaul and the Iberian peninsula were the source of an abundant supply of copper and brass coins issued over a short period of time.

Growth in excess copper induces changes in the lipid composition and fluidity of PSII‐enriched membranes in wheat

Changes in the lipid composition and fluidity of PSII‐enriched thylakoids were studied in seedlings of wheat (Triticum durum Desf. cv. Adamello) grown in nutrient solution supplemented with CuSO4 to achieve a final concentration of 10 and 50 μM Cu. Metal content increased in the chloroplasts of the 50 μM Cu‐grown plants. PSII isolated from wheat supplied with 10 μM Cu did not show any alteration in the lipid composition or in the lipid and protein levels of the membranes, nor was any change in the ultrastructure of the membranes detected. The 50 μM Cu‐grown plants showed thylakoid swelling, particularly in the stroma and terminal grana thylakoids. Furthermore, an alteration in the lipid composition of PSII preparations was observed together with a decrease in the lipid content, which resulted in a reduction in the lipid to protein ratio. The monogalactosyldiacylglycerol (MGDG) to digalactosyldiacylglycerol (DGDG) molar ratio decreased, whereas the degradation of the polar lipids caused an accumulation of free fatty acids (FFA). The total amount of unsaturated lipids associated with the PSII‐enriched membranes of wheat was not affected by excess copper supplies, even though changes in the individual fatty acids occurred. The effect of copper on the fluidity of PSII membranes was evaluated by electron paramagnetic resonance (EPR) measurements, using spin‐probed fatty acids as probes. The PSII membranes, spin probed by means of 5‐ and 16‐doxylstearic acids, showed that only the fluidity of the surface region of the bilayer close to the polar head group was reduced following the 50 μM Cu supply. In contrast, the fluidity of the inner membrane region of the bilayer did not show any change. The implications of changes in the lipid composition and lipid‐protein interactions on the fluidity of specific transversal membrane regions are discussed.

Growth in excess copper induces changes in the lipid composition and fluidity of PSII-enriched membranes in wheat

Changes in the lipid composition and fluidity of PSII-enriched thylakoids were studied in seedlings of wheat (Triticum durum Desf. cv. Adamello) grown in nutrient solution supplemented with CuSO4 to achieve a final concentration of 10 and 50 μM Cu. Metal content increased in the chloroplasts of the 50 μM Cu-grown plants. PSII isolated from wheat supplied with 10 μM Cu did not show any alteration in the lipid composition or in the lipid and protein levels of the membranes, nor was any change in the ultrastructure of the membranes detected. The 50 μM Cu-grown plants showed thylakoid swelling, particularly in the stroma and terminal grana thylakoids. Furthermore, an alteration in the lipid composition of PSII preparations was observed together with a decrease in the lipid content, which resulted in a reduction in the lipid to protein ratio. The monogalactosyldiacylglycerol (MGDG) to digalactosyldiacylglycerol (DGDG) molar ratio decreased, whereas the degradation of the polar lipids caused an accumulation of free fatty acids (FFA). The total amount of unsaturated lipids associated with the PSII-enriched membranes of wheat was not affected by excess copper supplies, even though changes in the individual fatty acids occurred. The effect of copper on the fluidity of PSII membranes was evaluated by electron paramagnetic resonance (EPR) measurements, using spin-probed fatty acids as probes. The PSII membranes, spin probed by means of 5- and 16-doxylstearic acids, showed that only the fluidity of the surface region of the bilayer close to the polar head group was reduced following the 50 μM Cu supply. In contrast, the fluidity of the inner membrane region of the bilayer did not show any change. The implications of changes in the lipid composition and lipid-protein interactions on the fluidity of specific transversal membrane regions are discussed.

Can an increased copper requirement in copper-tolerant Mimulus guttatus explain the cost of tolerance? II. Reproductive phase.

Circumstantial evidence suggests that plants that have evolved metal tolerance are at a disadvantage on normal soil, i.e. there is a cost of tolerance. One hypothesis for the cause of this cost is that individuals have a greater requirement for copper, and so suffer micronutrient deficiency on normal soils, as a result of a reduced uptake, distribution and/or utilization of copper. We provided highly and less copper-tolerant plants of Mimulus guttatus Fischer ex DC. (the common monkey flower) with sub-optimal copper, and demonstrated the importance of copper as an essential micronutrient during the reproductive phase, both in the production of viable pollen and in seed set. We also looked at the effect of sub-optimal copper supply on the growth of the microgametophyte, and the efficiency with which seed was set. No evidence was found that highly tolerant plants have an increased copper requirement during the reproductive phase. This is in agreement with earlier work on Mimulus guttatus, which investigated the copper requirement of highly tolerant plants during vegetative growth and found that any differences in copper requirement were small. The 'metal requirement hypothesis' is, therefore, not the sole explanation for the cost of copper tolerance in M. guttatus.

Nitrogen fixation in several grain legume species with contrasting sensitivities to copper nutrition

The nitrogen fixation response to copper nutrition in faba bean, yellow lupin and soybean was studied. Copper nutrition significantly increased the pod yields of all tested grain legumes but faba bean gave the greatest Cu-use efficiency for pod and grain production. The accumulation of dry matter in vegetative parts, nodules, N and leghemoglobin concentration in nodules and nitrogen accumulation in the whole plants were increased by copper supply in faba bean and yellow lupin in contrast with soybean. Cu nutrition significantly increased the Cu concentrations in nodules of all cultivated plants. The differential sensitivity of N2 fixation in tested grain legume species to copper nutrition could be connected with the level of phenols in nodules and depended on both the host plants and strains of rhizobia, which differ in their ability to produce catechol-like siderophores. Copper requirements by symbiotic N2 fixation could also depend on the nature of phenols in nodules (presence of o-dihydroxyphenols or number of hydroxyls in molecule).

Steady‐state nutrition and growth responses of Betula pendula to different relative supply rates of copper

In a series of experiments on the growth and nutrition of copper‐limited birch (Betula pendula Roth) plants, growth was controlled by the relative addition rate of copper, RCu (d–1). This was 0·05, 0·10, 0·15 or 0·20 d–1 with free access to all other nutrients. An additional treatment provided free access to all nutrients. The pH in the nutrient solution was ≈ 4·5 and conductivity was 100 μS cm–1. At steady‐state growth, there was a linear relationship between the relative growth rate, RG, and RCu. The [Cu] of the plants ranged from 2·4 to 2·7 μg g–1 dry mass (DM) in all treatments with limiting RCu and was ≈ 28 μg g–1 in the free access treatment. The plants showed specific copper deficiency symptoms at limitation. Total non‐structural carbohydrate concentrations and the fraction of plant DM partitioned to roots was much less at copper limitation than at free access. The uptake rate of copper per unit root growth rate, dCu/dWr (μmol g–1 root DM) was unaffected by the copper supply. Low rates of plant growth at copper limitation were associated with high values of specific leaf area (SLA; 47 m2 kg–1) and leaf area ratio (LAR; 28 m2 kg–1 plant DM) but lower values of net assimilation rate (NAR; 2·5 kg m–2 leaf DM d–1) than were found at free access, 28 m2 kg–1 (SLA), 17 m2 kg–1 DM (LAR) and 14 kg m–2 leaf DM d–1 (NAR), respectively. It is not obvious from the present data how the growth response can help alleviate copper limitation in the field.

Essentiality of copper in humans

The biochemical basis for the essentiality of copper, the adequacy of the dietary copper supply, factors that condition deficiency, and the special conditions of copper nutriture in early infancy are reviewed. New biochemical and crystallographic evidence define copper as being necessary for structural and catalytic properties of cuproenzymes. Mechanisms responsible for the control of cuproprotein gene expression are not known in mammals; however, studies using yeast as a eukaryote model support the existence of a copper-dependent gene regulatory element. Diets in Western countries provide copper below or in the low range of the estimated safe and adequate daily dietary intake. Copper deficiency is usually the consequence of decreased copper stores at birth, inadequate dietary copper intake, poor absorption, elevated requirements induced by rapid growth, or increased copper losses. The most frequent clinical manifestations of copper deficiency are anemia, neutropenia, and bone abnormalities. Recommendations for dietary copper intake and total copper exposure, including that from potable water, should consider that copper is an essential nutrient with potential toxicity if the load exceeds tolerance. A range of safe intakes should be defined for the general population, including a lower safe intake and an upper safe intake, to prevent deficiency as well as toxicity for most of the population.

Laramide alteration of Proterozoic diabase; a likely contributor of copper to porphyry systems in the Dripping Spring Mountains area, southeastern Arizona

Proterozoic diabase of the Dripping Spring range occurs as sills in the Proterozoic Apache Group and the Troy Quartzite and as intrustive sheets in basement rocks. The aggregate thickness of the diabase sills and intrusive sheets averages about 450 m in the part of the range showing little mid-Tertiary extension. Laramide alteration is of two types, dominated by chlorite and actinolite, respectively, and formed mostly from clinopyroxene. Actinolite-dominated assemblages are higher in Na and Ca. Hydrothermal biotite is common in the central areas of both alteration types. Laramide alteration forms two distribution patterns: a subsequent pattern centered on Laramide intrusions and small porphyry deposits, characterized by actinolitic alteration, and a more extensive branching linear pattern that follows Laramide structures, centered on the larger Ray porphyry deposit, extending toward other Laramide districts and showing both alteration types. Alteration has apparently mobilized copper and other metals from diabase. The freshest diabase samples average about 120 ppm copper with little variation. In chloritic alteration, about 100 ppm of this copper is expelled in the most completely altered rocks. In actinolitic alteration, diabase may either gain or lose copper during alteration. Chloritic alteration constitutes roughly 70 percent of the diabase alteration in the study area, where alteration averages 41 percent complete. This implies liberation of about 9X10 6 tons (t) copper from diabase alteration, significantly less than the 16X10 6 t copper in Laramide mineral deposits of the superdistrict Ray, Superior. Chilito. Christmas. However, diabase alteration may have been a significant component of the supply of copper to the Laramide mineral districts of the area. Synmineral magmatic sources of copper are not documented in this area. The distribution of Proterozoic diabase coincides with the central part of the southeastern Arizona copper province, which may thus owe much copper availability to an unusual abundance of diabase. However, many unanswered questions remain about metal supply from altering diabase.

CAPACITY AND PRICE OF NONRENEWABLE RESOURCE DEPOSITS

This paper develops a model to determine the planned rate of production from a nonrenewable resource deposit and applies the model to the U.S. copper industry to estimate changes in aggregate planned copper production as a function of copper price expectations. Standard investment theory is applied in the model to examine the choice of the planned rate of extraction from limited volume resource deposits. A setting is analyzed in which the total production volume from any site is fixed by the size of the resource deposit at that site. Within this setting, the planned rate of resource extraction is a fully endogenous solution of the model. Properties of the model are investigated to determine changes in the planned rate of production caused by variation in operating cost, investment cost and output price parameters. The planned rate of production from any deposit is found to increase at a decreasing rate, given incremental increases in the output price, ceteris paribus. The finding is illustrated with data describing mined and yet-to-be mined copper deposits in the United States. A close match is observed between the calculated production rate for mined copper deposits and the mine capacity (rate of production) chosen by the owners of those deposits, given plausible assumptions about mine owner price expectations. The planned rate of production is aggregated across all deposits and plotted as a function of output price. An aggregate medium run copper supply curve is obtained, indicating the elasticity of planned production to changes in the expected long run output price of copper. This empirical example suggests that doubling the output price from $1 to $2 per pound copper, would triple aggregate planned copper production in the United States.

The Effects of Low Dietary Copper Intake During Pregnancy on Physiological Fluids and Reproductive Performance of First-litter Gilts

Seven pairs of first littermate gilts were used to study the influence of low copper supply and pregnancy on physiological fluids and reproductive performance of first-litter gilts. They were fed semi-purified diets containing either 2.13 or 12.25 micrograms/kg of Cu from 30 days of gestation through two weeks of lactation. Low-Cu gilts had lower plasma Cu in early- and mid- gestation and farrowed piglets with lower plasma Cu and higher plasma Zn concentrations (p < 0.05). Plasma Fe and Mn concentrations were not affected by Cu supply (p > 0.05). Plasma Cu and Fe levels of newborn piglets were lower than those of their dams (p < 0.05) but this was not true for plasma Zn and Mn (p > 0.05). Low-Cu gilts had lower Cu and higher Zn content in colostrum and also lower Cu in milk than control gilts (p < 0.05). No significant differences were found in Fe and Mn levels in colostrum and milk between the two treatments (p > 0.05). Colostrum was richer in Cu and Zn than milk (p < 0.05) but not in Fe and Mn (p > 0.05). The low-Cu diet did not affect (p > 0.05) weight changes during pregnancy. The duration of parturition was shorter for low-Cu than for control gilts (3.19h vs. 5.71h, p < 0.05). Control gilts farrowed larger litters than low-Cu gilts (9.71 vs. 7.57 piglets, p < 0.05). There were no significant differences in live litter weights at birth, one wk. or two wks. of age (p > 0.05). The results indicated that a low-Cu diet and pregnancy had some effect on plasma, colostrum and milk mineral concentrations, as well as on litter size of gilts. An interaction between Cu and Zn was found.

Zinc and copper in infants fed breast-milk or different formula.

In 129 term infants at birth and at the age of 4 months, zinc and copper concentrations of plasma and urine were determined by graphite furnace atomic absorption spectrophotometry and the values correlated to other biochemical parameters and somatic data. Of the infants, 49 were exclusively breast-fed, 44 fed with various commercially available cow's milk formula, 35 fed with a hypoallergenic formula (cows's milk whey hydrolysate, commercially available, supplemented with zinc and copper). Plasma zinc values declined from birth to the age of 4 months in all three groups (P < 0.001). In formula fed children, 4 months old, the values (11.1 +/- 1.7 mumol Zn/l) were significantly lower than in breast-fed (12.2 +/- 1.7 mumol Zn/l; P = 0.004) or babies on hypo-allergenic formula (12.4 +/- 1.6 mumol Zn/l; P = 0.0015). In accordance with the literature plasma copper and caeruloplasmin values increased significantly within the first 4 months of life, the plasma levels were similar in either feeding group, only urinary copper excretion was higher in male infants on hypo-allergenic formula (P < 0.03) at the age of 4 months. There were no correlations between zinc or copper values and alkaline phosphatase. In infants on hypo-allergenic formula there was a negative correlation between plasma zinc and weight or height increments. Despite different zinc and copper supply, presumedly different bioavailability, and different plasma zinc values, all infants thrived and weight and length increments were similar in each group.

Comparative Responses of a Copper-tolerant and a Copper-sensitive Population of Minuartia hirsuta to Copper Toxicity

The response of two populations of Minuartia hirsuta with different copper tolerance to an excess of copper was studied. The population originatin from copper contaminated sites showed a distinct tolerance to copper. A more vigorous growth of copper tolerant plants under increasing copper concentrations was found, since their root-length growth and chlorophyll content were higher than the control, as well as their unchanged percentage survival. In contrast, copper treatments caused progressive reduction in the above mentioned parameters in copper-sensitive plants. The total uptake of copper and its distribution between roots and shoots differ significantly between the two populations. At all external copper concentrations the sensitive plants took up more copper, and a higher percentage of the total copper concentration was allocated to the shoot, compared with the tolerant plants. A distinct population differentiation was observed with respect to the distribution of calcium, magnesium, iron and potassium in roots and shoot-leaves. Under copper treatments the sensitive population showed a direct relation to the calcium concentration both in roots and shoot-leaves, while the tolerant population revealed an inverse relation to calcium concentration in plant tissues. The magnesium concentration decreased in the presence of increasing copper levels both in tolerant and, especially, sensitive populations. The total iron concentration seems to be unaffected under an excess of copper in tolerant plants, while an inverse relation of iron concentration to external copper supply in the sensitive population was observed. The concentration of potassium dropped more in sensitive plants. It seems likely that a constitutive copper tolerance mechanism also operates both in shoot and root and that this also contributes to the increased copper requirements of tolerant plants.

Les ceitis portugais (XVe - XVIe siècles) : composition des alliages utilisés et problèmes numismatiques

Summary. — For 120 years (15th to 16th century) the ceitil was struck with the same basic typology. Controversial for the lack of reference documents, this coinage reveals difficulties as the attribution of the monetary letters to the mints or the evolution of its legal value and weigh. The metrological data obtained over more than 10 000 coins, the study of its slight typological evolution and the few known documents, allowed to propose a relative chronology for this coinage. To confirm this relative chronology about 300 coins covering almost all the typological groups were non destructively analysed using a global method based on fast neutrons cyclotron activation. The evaluated chemical compositions showed that coins struck with monetary letter « С » were similar to those with a « L » (Lisbon mint) as well as the existence of several copper supply sources and the absence of the previous copper coinage recasting for striking the ceitil

Stem deformation in fast grown Pinus radiata: an investigation of causes

The incidence of deformed stems and poor form of Pinus radiata (D. Don) growing on ex-pasture sites in south-eastern Australia has been termed the Toorour syndrome. The syndrome appears to be under genetic control and stimulated by high nitrification in the soil. The influence of weather conditions, stem structure, nitrogen (N) availability and copper (Cu) supply on the onset of Toorour syndrome was examined. Trees deformed most markedly during a late-spring flush when the weather was warmer, wetter, and windier than previously; there was no distinct meteorological cause, except that strong wind created the mechanical disturbance. During this warm, wet and windy period the form of N in meristematic tissue changed as the trees flushed; the ratio of soluble N to total N dropped dramatically. Concentrations of Cu in buds decreased over time and also were lower in trees that received N and P fertiliser than those that did not. No structural or anatomical differences between form classes were found that could be attributed to the onset of stem bending. Tissue produced prior to deformation in deformed trees did not have lower density, shorter tracheids, or larger microfibril angles. It was not possible to define weather conditions, N availability, or Cu supply to meristematic tissue as a single causative factor in the Toorour syndrome. Many variables changed coincidentally with stem sinuosity, but none were found to be linked clearly and causatively with the syndrome. The nutritional physiology of the syndrome, if one exists, is not much better defined. The question as to whether there is an important and functional difference in nutritional physiology between straight and deformed trees remained unanswered.

Copper supply and the leaf emergence rate of spring wheat

Copper deficiency can delay flowering and plant maturity. However, the effect of copper deficiency on the rate of leaf emergence has not been quantified. We tested the hypothesis that low copper supply decreases the rate of leaf emergence of wheat (Triticum aestivum L. cv Gamenya). Copper foliar sprays are commonly applied to wheat. We examined the response of the rate of leaf emergence to a foliar application of copper sulphate.

Commodities, Transactions, and Growth in the Central-European Early Bronze Age

Abstract This paper suggests that recent studies of the beginning of the Bronze Age and the growth of a bronze 'industry' have placed too much emphasis on the importance of social ranking and the control of resources by elites. Copper had been in demand for over 2000 years before the beginning of the Bronze Age. What changed at this time was the emergence of a technology that gave access to virtually unlimited copper supplies and contributed to a process of economic growth. Circulating metal took on the role of a proto-currency in certain areas and had a significant effect on local patterns of social organisation. It was not centrally controlled. Eventually, the end of the growth process led to increased competition and warfare. Studies of these processes are illuminated by looking at the circulation of metal and money in medieval Europe and by thinking of the social changes in terms of Douglas's' grid' and 'group' dimensions.

Atomic Layer Growth of SrCuO2 Thin Film by Molecular Beam Epitaxy.

Thin films of SrCuO2 with a tetragonal structure have been synthesized by molecular beam epitaxy. Two different patterns have been observed by reflection high-energy electron diffraction (RHEED) during the alternating supply of strontium and copper under the flow of NO2. Incommensurate streaks appear during the copper supply. The intensity of the incommensurate streak decreases to zero with the strontium supply. We demonstrate that an exact control of the elemental composition of Sr and Cu can be carried out using in-situ intensity monitoring of the incommensurate streak.

Foliar catechol oxidase activity as a measure of copper nutrition of tomato plants

AbstractThe diagnostic value of catechol oxidase assays as indices of copper nutritional status was investigated in tomato plants (Lycopersicon esculentum Mill) receiving graded copper treatment in sand culture. Foliar copper concentrations ranged from 0.79 to 5.16 μg g−1 dry matter under various copper treatments but these results were misleading because copper‐inadequate plants concentrated the element in older leaves. A colorimetric assay based on catechol oxidase‐catalysed formation of measurable quinones in young tomato leaves discriminated sufficiently between the various copper treatments. The rates of invitro induction of this enzyme amounted to an expression of the plant growth response to copper supply and thus was indicative of the copper requirement of the plant. A paper strip‐based modification of the enzyme assay simplified it further for diagnostic use in field situations.

The role of exploration in iron and copper supply

The development histories of approximately 200 each iron and copper mine openings in the non-centrally-planned-economies from the mid-1800s through the mid-1980s are analyzed to determine the role of exploration in mineral supply. The research shows that approximately 75 percent of the iron mines and 50 percent of the copper mines opened since World War II do not result from the prompt development of new discoveries. The mine openings result from the reevaluation of mineralization or orebodies that are previously recognized, which become economic under changed technologic or market conditions. Although the incentive for exploration is normally the expectation that high-profit deposits exist to be found, the supply of new mines does not depend critically on whether such high-profit deposits are discovered. Studies that predict scarcity of resources arising from the failure of exploration to uncover new, highprofit deposits thus do not adequately explain the mineral supply process.

Copper-induced Damage to the Permeability Barrier in Roots of Silene cucubalus

The mechanism of copper-induced damage to cell plasma membrane functioning in intact roots of Silene cucubalus was studied by comparing the effects of high copper ion concentrations with those of Nethylmaleimide (NEM), a sulfhydryl-reagent, and of cumene hydroperoxide (CHP), an organic peroxide known to induce lipid peroxidation by free radical formation. Leakage of potassium ions from roots (a measure of cell permeability) was detected directly upon supply of copper or NEM, whereas with CHP a 45 minutes time-lag was observed. In copper or CHP treated plants, leakage was constant for at least three hours and, as demonstrated by trypan blue staining after a 24 hour exposure, the plasma membranes of root cells were severely damaged, especially in the tips. A marked increase of lipid peroxidation products was detected in roots treated with these reagents, although the increase was highest with copper. In contrast, with NEM potassium leakage diminished after about 1 hour, dye staining of root cells was negligible and the level of lipid peroxidation products did not increase. When NEM plus CHP were added, the results were the same as those obtained with high copper supply, suggesting a combined effect of thiol depletion and lipid peroxidation by copper ions. In addition, it was shown in vitro that copper ions stimulate lipid peroxidation in microsomes isolated from roots of plants grown at a normal low copper supply. These results suggest that, apart from thiol depletion, direct free radical formation leading to lipid peroxidation might play an important role in the mechanism of copper-induced damage to the permeability barrier in roots of higher plants in vivo.