The metals price boom of 1987-89 : the role of supply disruptions and stock changes

The markets for base metals have changed remarkably in the last few years. A long period of extremely low prices was followed by a sustained price boom in 1987-89 - which continued into 1990 for copper, nickel, lead, and zinc. The author examines the causes of the price boom in terms of market fundamentals. Because of the importance of supply disturbances and low stocks, the reduced-form price equation specification was extended to incorporate supply-side variables. The resulting estimates exhibit superior fit and greater explanatory power than, for example, those of Gilbert's (1986) model. The estimates of the modeland simulations of the boom period with the model suggest the following: 1) The growth of OECD industrial production was the most important factor in the higher metals prices, 2) US dollar depreciation was the dominant contributor to the metals price increase during the earlier part of the boom, 3) supply disturbances and low stocks had positive impacts on the price increases, and 4) excessive market speculation exacerbated the price increases.Access to Markets,Economic Theory&Research,Mining&Extractive Industry (Non-Energy),Environmental Economics&Policies,Markets and Market Access

Global trends in raw materials consumption

This paper reviews movements in raw materials consumption over the past 30 years. Included in this review are all base metals and steel, and important agricultural raw materials. These primary commodities share the common characteristic that they are used as inputs in manufacturing and construction. Some metals and minerals, energy commodities, and timber products are not included in this review for various reasons. The period reviewed is from 1961 to 1988. A prominent characteristic of the metals market during the past 15 years has been its very slow growth. In some years consumption of several raw materials has even declined. Explaining the causes of this slowdown, in the face of moderate economic growth, has become a topical issue. The slowdown has important implications for a number of developing countries that rely heavily on exports of these materials. The severity and persistence of post-1973 declines in metals intensity per unit of GNP, prompted the conjecture that it may have been structural. This paper reviews the debate on this issue, including results of statistical tests. It also summarizes the trends in raw materials consumption and reviews the technological developments relating to raw materials consumption.Mining&Extractive Industry (Non-Energy),Montreal Protocol,Sanitation and Sewerage,Primary Metals,Environmental Economics&Policies

Commodity price forecasts and futures prices

The International Commodity Markets Division (CM) of the World Bank started forecasting primary commodity prices more than two decades ago. The forecast accuracy, or forecast biases and informational efficiency, has been a major concern and the subject of occasional retrospective studies. This paper explores the relationship between commodity futures prices and price expectations. It focuses of the usefulness of futures prices as a short-term price forecasting tool. In 1989, Froot and Frankel used survey data on exchange rate expectations to estimate the relative importance of risk premium and expectational error in explaining the forward discount biases in foreign exchange rates. They found that expectational errors dominate the forward discount bias and that the risk premium is small, relatively stable, and not correlated with the expectational error. This paper follows the Froot and Frankel analysis to see if commodity prices exhibit similar characteristics. It goes a step further and estimates a relationship between futures prices and price expectations. The paper summarizes the characteristics of the forecast and futures price data, tests the rationality of futures prices and decomposes the futures price bias. It also conducts direct statistical tests of the importance of risk premium and expectational error.Commodities,Access to Markets,Markets and Market Access,Environmental Economics&Policies,Economic Theory&Research

Rational expectations and commodity price forecasts

The main purpose of this paper is to take a new look at the commodity market (CM) price forecasts in light of recent investigations. The CM forecasts are similar in nature to the survey expectations in that both solicit market experts'opinions about future price developments. However, there are important differences: CM forecasts are more of the consensus-type forecasts than survey data and deal with physical goods that are subject to different risks and constraints. The characteristics of the CM forecasts are reviewed in relation to the futures prices of the same commodities. This paper also estimates the alternative expectational models and tests the rationality of the expectational behavior.Economic Forecasting,Economic Theory&Research,Environmental Economics&Policies,Access to Markets,Markets and Market Access

Emploi du triclopyr pour l'éradication des recrûs arbustifs en plantation de palmiers à huile

La préparation des terrains en vue de la réalisation d'une plantation de palmiers en forêt ou en replantation, consiste à effectuer un abattage manuel ou mécanique. Cet abattage est suivi d'un premier brûlage pour le précédent forêt. Ensuite, un andainage mécanique est effectué dans la plupart des cas. L'intervalle d'andainagc peut varier selon les options choisies et les conditions de terrain, la technique de l'andainage alterné demeurant la meilleure du point de vue agronomique (bonne répartition des restitutions de matière organique, effet certain de paillage des andains, moindre risque de détérioration des couches superficielles humifères lors de l'andainage). Parfois, un brûlage total est réalisé (technique facilitant les opérations d'entretien mais peu satisfaisante du point de vue agronomique). Ces opérations sont suivies du semis d'une plante de couverture (en général Pueraria phaseoloides) et de la mise en place des plants. Pendant 5 à 6 ans après ces opérations, l'ombrage arbustif est donc nul ou très réduit et, malgré la présence de plante de couverture, un recrû arbustif est susceptible de se développer très rapidement. Théoriquement des rabattages sélectifs périodiques tous les 2-3 mois seraient suffisants pour enrayer ce développement. Très fréquemment, la main-d'oeuvre faisant défaut, le recrû arbustif s'installe. Ce recrû arbustif est principalement constitué par les espèces suivantes : Musanga cecropioides (Fig. 1), Alchornea cordata, Dillenia reticulata (Fig. 2) et Campnosperma auriculata (Fig. 3). D'autres espèces peuvent être occasionnellement rencontrées. Afin d'éviter que ce recrû ne prenne trop d'importance et constitue une gêne pour les autres opérations d'entretien et les arbres, des traitements chimiques ont été mis au point. Les herbicides essayés ont été les suivants : - acide 2,4-dichlorophenoxyacétique (2,4-D), sous différentes formes ; - acide 2,4,5-trichlorophenoxyacétique (2,4,5-T), sous différentes formes ; - acide (phosphonométhyl ammo)-2 acétique sous forme de sel d'isopropyl amine (glyphosate) ; - acide 3,5,6-trichloro-2-pyridinyloxyacétique sous forme d'ester butylglycol (triclopyr). Les essais réalisés ont montré que le 2,4-D était insuffisamment efficace, même sous forme d'ester butylglycol. Les trois autres herbicides sont efficaces (quelle que soit la forme pour le 2,4,5-T). Le 2,4,5-T n'étant plus fabriqué, en raison des résidus de dioxine, seuls le glyphosate et le triclopyr demeurent utilisables. Les résultats des essais ont montré que, compte tenu des prix et des doses d'emploi, le triclopyr était l'herbicide le plus intéressant (coût de traitement triclopyr équivalent à celui du 2,4,5-T en raison de la très faible quantité de matière active triclopyr nécessaire). (Résumé d'auteur

Evaluation of the modified colorimetric resazurin microtiter plate-based antibacterial assay for rapid and reliable tuberculosis drug susceptibility testing

Background: The resazurin microtiter assay (classic REMA), a colorimetric liquid culture-based drug susceptibility assay for Mycobacterium tuberculosis (MTB), has been endorsed by the World Health Organization. The assay requires 8-16 days to obtain results, delaying management of drug resistant tuberculosis patients. A modified REMA which allows results in as little as 24 hours for bacterial strains, has been developed and validated using Staphylococcus aureus, but has not yet been evaluated for MTB. Therefore we assessed the performance of the modified REMA for rifampicin (RIF) and isoniazid (INH) susceptibility, using the classic REMA as the reference standard. We also compared simplicity (from the technicians’ point of view), time taken to obtain results (rank-sum testing), specificity and Kappa statistics of the two methods. Results: The modified REMA, which is a one-step procedure, was found to be simpler to perform and results were obtained in a significantly shorter time (5 versus 9 days, p < 0.0001) compared to the classic REMA due to addition of indicator and strain at the same time. The specificity of the modified REMA was low {46.8% (35.5% - 58.4%) for RIF and 13.9% (7.2% - 23.5%) for INH}. Kappa statistics were 16.0% for RIF and 2.0% for INH. Low specificity and kappa statistics are due to indicator reduction by the strains before complete drug activity. Conclusion: Although modified REMA is faster and simpler compared to classic REMA, it is not reliable for MTB drug susceptibility testing

Evaluation of the SD BIOLINE HIV/syphilis Duo assay at a rural health center in Southwestern Uganda

Background: Point-of-care tests have the capacity to improve healthcare delivery by reducing costs and delay associated with care. A novel point-of-care immunochromatographic test for dual diagnosis of both HIV and syphilis by detecting IgG, IgM and IgA antibodies to HIV, and specific and recombinant Treponema pallidum antigens has recently been developed, but has not been evaluated in rural field settings. We evaluated the performance of the SD Bioline Syphilis/HIV Duo (Duo) assay at a healthcare center in rural Uganda. Methods: A convenience sample of pregnant women attending Kinoni Health Centre IV from March to May, 2013 was enrolled. Venous blood was collected and centrifuged for plasma isolation. Samples were tested with the Duo assay and compared with the Treponema pallidum hemaglutination assay and paired HIV rapid antibody tests as the reference standards. The ease of use and time required for the Duo assay were also assessed by laboratory technicians. Results: Two hundred twenty women were enrolled with a mean age of 25.00 years (SD 5.41). The sensitivity and specificity of the Duo assay were 100% (95% CI 79.0 – 100%) and 100% (95% CI 97.6 – 100.0) respectively, for syphilis, and, 100% (75.9 – 100%) and 99.5% (96.8 – 99.9%) respectively, for HIV. The duo kit was found to be faster and easier to use than the current HIV and syphilis testing techniques. Conclusion: The sensitivity and specificity of the SD Bioline HIV/Syphilis Duo test were excellent in a field setting in Uganda. The Duo assay should be further evaluated in alternate populations and with point-of-care specimens (e.g. whole blood from finger stick specimens), but shows promise as a tool for improved HIV and syphilis surveillance, diagnosis, and treatment in field settings

Comparison of Self-Reported Alcohol Consumption to Phosphatidylethanol Measurement among HIV-Infected Patients Initiating Antiretroviral Treatment in Southwestern Uganda

Background: Alcohol consumption among HIV-infected patients may accelerate HIV disease progression or reduce antiretroviral therapy adherence. Self-reported alcohol use is frequently under-reported due to social desirability and recall bias. The aim of this study was to compare self-reported alcohol consumption to phosphatidylethanol (PEth), a biomarker of alcohol consumption, and to estimate the correlation between multiple measures of self-reported alcohol consumption with PEth. Methods: The Uganda AIDS Rural Treatment Outcomes (UARTO) cohort is located in southwestern Uganda and follows patients on ART to measure treatment outcomes. Patients complete standardized questionnaires quarterly including questions on demographics, health status and alcohol consumption. Baseline dried blood spots (DBS) were collected and retrieved to measure PEth. Results: One hundred fifty samples were tested, and 56 (37.3%) were PEth positive (≥8 ng/mL). Of those, 51.7% did not report alcohol use in the past month. Men were more likely to under-report compared to women, OR 2.9, 95% CI = 1.26, 6.65) and those in the higher economic asset categories were less likely to under-report compared to those in the lowest category (OR = 0.41 95% CI: 0.17, 0.94). Among self-reported drinkers (n = 31), PEth was highly correlated with the total number of drinking days in the last 30 (Spearman R = 0.73, p<0.001). Conclusions: Approximately half of HIV infected patients initiating ART and consuming alcohol under-report their use of alcohol. Given the high prevalence, clinicians should assess all patients for alcohol use with more attention to males and those in lower economic asset categories who deny alcohol use. Among those reporting current drinking, self-reported drinking days is a useful quantitative measure