Amalgamation and small-scale gold mining in the ancient Andes

In 1532, the volume of gold provided by Atahualpa, the Inka king, as ransom for his release from the Spanish was hard evidence for the efficient small-scale gold mining that took place before European contact and the number of gold occurrences in the Andes. At Huancavelica, Perú, mercury occurs as a native metal and as cinnabar [HgS], which was used for pigments, funeral preparations, and retorted to obtain mercury. Using Inductively Coupled Plasma analysis (ICP), an average of 15 ppm (parts per million) mercury was found in the gold after the gold-mercury amalgam, with more than 300 000 ppm mercury, was burned to volatilize (rogado) the mercury. From 12,3 to 13,9 ppm mercury was found in worked gold foils from Huaca la Ventana, a Middle Sicán (A. D. 900-1200) site at Lambayeque, Perú and low levels of mercury were found in pre-contact gold foils from Colombia (1-12 ppm). Similarly low levels of mercury in the analyses of modern refogado gold and pre-contact gold foils are consistent with a comparable, ancient small-scale mining technology that would have used mercury to amalgamate the fine-grained gold; and then, as now, burning the amalgam to volatilize the mercury and beautify and recover the gold.En 1532, el volumen de oro proporcionado por el Inca Atahualpa, como rescate por liberarlo de los españoles, fue una prueba difícil para la minería de oro eficiente a pequeña escala que tuvo lugar antes del contacto europeo y la cantidad de oro disponible en los Andes. En Huancavelica, Perú, el mercurio se presenta como un metal nativo y como cinabrio (HgS), que fue utilizado para los pigmentos, los preparativos funerarios y para obtener mercurio. Utilizando el análisis llamado Induced Coupled Plasma (ICP), un promedio de 15 ppm (partes por millón) de mercurio fue encontrado en el oro después de que la amalgama oro-mercurio (>300 000 ppm de mercurio) haya sido quemada o refogada para volatilizar el mercurio, en las tiendas modernas de oro en Madre de Dios, Perú. De 12,3 a 13,9 ppm de mercurio fue encontrado en láminas de oro trabajado en Huaca la Ventana, Sican Medio (900-1200 d. C.), Lambayeque, Perú y bajos niveles de mercurio fueron encontrados en las láminas pre-contacto de oro de Colombia (1-12 ppm) y Ecuador. Asimismo, los bajos niveles de mercurio medidos en el análisis ICP de oro refogado moderno (charapitas) y pre-contacto (láminas de oro) son consistentes con los valores esperados utilizando una antigua tecnología de pequeña minería. Para eso se usa métodos de separación por gravedad y de amalgama de mercurio para el tratamiento del grano fino y vena de oro de los lavaderos, y entonces, como ahora, el refogado de la amalgama hace volitilizar el mercurio, para embellecer y recuperar el oro.En 1532, la quantité de l’or fourni par Atahualpa, le souverain Inka, pour payer sa rançon aux Espagnols constitua une dure épreuve pour l’industrie minière à petite échelle à l’époque pré-hispanique et un indicateur de la quantité d’or disponible dans les Andes. À Huancavelica, au Pérou, le mercure est considéré comme un métal d’origine et comme du cinabre (HgS), utilisé pour les pigments, pour les préparatifs funéraires et pour obtenir du mercure. L’analyse par spectrométrie de masse à plasma inductif (ICP) d’échantillons modernes produits dans les ateliers de traitement d’or à Madre de Dios, Pérou, révèle la présence d’une valeur moyenne de 15 ppm de mercure dans l’or, après que l’amalgame a été brûlé (refogado), afin de volatiliser le mercure (>300 000 ppm de mercure). Par ailleurs, des concentrations de mercure entre 12 et 14 ppm ont été mesurées dans les feuilles d’or de la Huaca la Ventana, Pérou, un site Lambayeque Sicán moyen (900-1200 ap. J.-C.) et entre 1 et 12 ppm dans les feuilles d’or trouvées en Colombie et en Équateur à l’époque pré-hispanique. Les basses concentrations de mercure mesurées par ICP pour l’or refogado moderne et pour des feuilles d’or de l’époque pré-contact sont conformes aux valeurs attendues pour une technologie ancienne d’extraction à petite échelle qui aurait utilisé les méthodes de séparation par gravité et d’amalgame de mercure pour traitement de la fine poudre d’or des gisements et des filons ; il s’agissait donc, comme actuellement, de brûler l’amalgame de façon à volatiliser le mercure et récupérer l’or

Vegetable Crops Report: Variety Trials and Cultural Research Test, Muck Crops Branch, 1985

Onion variety trial, 1985 ; Celery variety trial, 1985 ; Broccoli variety trial 1985 ; Row cover evaluation 1985 ; Muskmelons ; Summer squash ; Celery transplants ; Celery seed beds ; Spring broccoli ; Seed quality and seed enhancements on lettuce production 1985 / Richard L. Hassell -- Fertilizer guidelines for vegetable crops grown on muck soils in Ohio / William M. Brooks, E. C. Wittmeyer, and Richard L. Hassel

DAMAS Processing for a Phased Array Study in the NASA Langley Jet Noise Laboratory

A jet noise measurement study was conducted using a phased microphone array system for a range of jet nozzle configurations and flow conditions. The test effort included convergent and convergent/divergent single flow nozzles, as well as conventional and chevron dual-flow core and fan configurations. Cold jets were tested with and without wind tunnel co-flow, whereas, hot jets were tested only with co-flow. The intent of the measurement effort was to allow evaluation of new phased array technologies for their ability to separate and quantify distributions of jet noise sources. In the present paper, the array post-processing method focused upon is DAMAS (Deconvolution Approach for the Mapping of Acoustic Sources) for the quantitative determination of spatial distributions of noise sources. Jet noise is highly complex with stationary and convecting noise sources, convecting flows that are the sources themselves, and shock-related and screech noise for supersonic flow. The analysis presented in this paper addresses some processing details with DAMAS, for the array positioned at 90 (normal) to the jet. The paper demonstrates the applicability of DAMAS and how it indicates when strong coherence is present. Also, a new approach to calibrating the array focus and position is introduced and demonstrated

ATM Quality of Service Tests for Digitized Video Using ATM Over Satellite: Laboratory Tests

A digitized video application was used to help determine minimum quality of service parameters for asynchronous transfer mode (ATM) over satellite. For these tests, binomially distributed and other errors were digitally inserted in an intermediate frequency link via a satellite modem and a commercial gaussian noise generator. In this paper, the relation- ship between the ATM cell error and cell loss parameter specifications is discussed with regard to this application. In addition, the video-encoding algorithms, test configurations, and results are presented in detail

Ambulatory monitoring of activity levels of individuals in the sub-acute stage following stroke: a case series

<p>Abstract</p> <p>Background</p> <p>There is an important need to better understand the activities of individual patients with stroke outside of structured therapy since this activity is likely to have a profound influence on recovery. A case-study approach was used to examine the activity levels and associated physiological load of patients with stroke throughout a day.</p> <p>Methods</p> <p>Activities and physiologic measures were recorded during a continuous 8 hour period from 4 individuals in the sub-acute stage following stroke (ranging from 49 to 80 years old; 4 to 8 weeks post-stroke) in an in-patient rehabilitation hospital.</p> <p>Results</p> <p>Both heart rate (p = 0.0207) and ventilation rate (p < 0.0001) increased as intensity of activity increased. Results revealed individual differences in physiological response to daily activities, and large ranges in physiological response measures during 'moderately' and 'highly' therapeutic activities.</p> <p>Conclusion</p> <p>Activity levels of individuals with stroke during the day were generally low, though task-related changes in physiologic measures were observed. Large variability in the physiological response to even the activities deemed to be greatest intensity suggests that inclusion of such extended measurement of physiologic measures may improve understanding of physiological profile that could guide elements of the physical therapy prescription.</p

Winning and losing: differences in reward and punishment sensitivity between smokers and nonsmokers

Background: Smokers show increased brain activation in reward processing regions in response to smoking-related cues, yet few studies have examined secondary rewards not associated with smoking (i.e., money). Inconsistencies exist in the studies that do examine secondary rewards with some studies showing increased brain activation in reward processing brain regions, while others show decreased activation or no difference in activation between smokers and nonsmokers. Aims: The goal of the current study is to see if smokers process the evaluation and delivery of equally salient real world rewards similarly or differently than nonsmokers. Methods: The current study employed functional magnetic resonance imaging (fMRI) to examine brain responses in smokers and nonsmokers during the evaluation and delivery of monetary gains and losses. Results: In comparison to nonsmokers, smokers showed increased activation in the ventromedial prefrontal cortex to the evaluation of anticipated monetary losses and the brain response. Moreover, smokers compared to nonsmokers showed decreased activation in the inferior frontal gyrus to the delivery of expected monetary gains. Brain activations to both the evaluation of anticipated monetary losses and the delivery of expected monetary gains correlated with increased self-reported smoking craving to relieve negative withdrawal symptoms and craving related to positive aspects of smoking, respectively. Discussion: Together these results indicate that smokers are hyperresponsive to the evaluation of anticipated punishment and hyporesponsive to the delivery of expected rewards. Although further research is needed, this hypersensitivity to punishments coupled with increased craving may negatively impact quit attempts as smokers anticipate the negative withdrawal symptoms associated with quitting

Do functional walk tests reflect cardiorespiratory fitness in sub-acute stroke?

BACKGROUND AND PURPOSE: The Six-Minute Walk Test (6MWT) has been employed as a measure of functional capacity, but its relationship to cardiorespiratory fitness in stroke is not well established. Gait speed measured over short distances is commonly used as an index of walking competency following stroke. We evaluated the relationship between the 6MWT, aerobic fitness (VO(2)peak) and walking competency in sub-acute stroke. METHODS: Thirty-six individuals (mean age ± SD, 64.6 ± 14.4 years; time post-stroke 16.2 ± 13.3 days) were evaluated using the 6MWT (distance, speed, heart rate), a maximal exercise test (VO(2)peak, heart rate, exercise test duration), and walking competency using a five meter walk (speed, symmetry ratio). Correlation analyses were used to examine the relationships between these outcomes. RESULTS: There was a strong correlation between the 6MWT and five meter walk velocity for preferred (r = 0.79) and fast (r = 0.82) speed (p < 0.001). On average, the 6MWT speed was faster than the preferred gait speed (94.9 cm/s vs. 83.8 cm/s, p = 0.003), but slower than the fast-paced walk (115.1 cm/s, p < 0.001). There was significant though more moderate association between 6MWT distance and VO(2)peak (r = 0.56, p < 0.001) and exercise test duration (r = 0.60, p < 0.001). CONCLUSION: The speed selected during the 6MWT was strongly related to the velocities selected during the five meter walk distance (intermediate to the selected preferred and fast speeds). Although the 6MWT may be challenging to the cardiorespiratory system, it appears to be more strongly influenced by potential limits to walking speed rather than cardiorespiratory capacity. As a result, this test is not, by itself, an adequate measure of aerobic fitness early after stroke

Mineral pigments at Huaca Tacaynamo (Chan Chan, Peru)

X-ray diffraction analyses of five samples of pigments from a recently excavated mural at the archaeological site of Huaca Tacaynamo, a part of the Chan Chan archaeological complex, northern Peru, show that minerals related to metal occurrences known to have been exploited by ancient Andeans were also used as pigments. These minerals include: atacamite [Cu2Cl(OH3)] for green; azurite [Cu3(CO3)2(OH)2] for blue; calcite [CaCO3] for white; cinnabar [HgS] for red; and goethite [HFeO2] for yellow. Woven plant material from Tacaynamo gave a calibrated, 2 sigma 14C date of AD 1412-1614; however, initial occupation of the site and painting of the murals may have been earlier.Los análisis de difracción de rayos x en 5 muestras de pigmentos de un mural, recientemente excavado en el sitio arqueológico de Huaca Tacaynamo —una parte del complejo de Chan Chan en el norte del Perú—, muestran ciertos minerales relacionados con presencias metálicas que, como se sabe, han sido aprovechados por los antiguos habitantes de los Andes, también, como pigmentos. Estos minerales incluyen atacamita [Cu2Cl(OH3)] para el color verde; azurita [Cu3(CO3)2(OH)2] para el azul; calcita [CaCO3] para el blanco; cinabrio [HgS] para el rojo; y goetita [HFeO2] para el amarillo. La datación de los tejidos a partir de materiales vegetales de Tacaynamo con el 14C dio como resultado: AD 1412-1614. Sin embargo, la ocupación inicial del sitio y la pintura de los murales bien podría haber sido previas.Les analyses de diffraction des rayons X sur cinq échantillons de pigments d’une peinture murale récemment découverte sur le site archéologique de Huaca Tacaynamo — qui fait partie du complexe de Chan Chan, au nord du Pérou —, indiquent la présence de minéraux connus pour avoir servi de pigments aux anciens habitants des Andes. Ces minéraux sont l’atacamite [Cu2Cl(OH3)] pour la couleur verte; l’azurite [Cu3(CO3)2(OH)2] pour le bleu; la calcite [CaCO3] pour le blanc; le cinabre [HgS] pour le rouge; et la goethite [HFeO2] pour le jaune. Le matériel tissé d’origine végétale retrouvé à Tacaynamo a donné un calibrage de 2 sigma 14C avec une date de AD 1412-1614; cependant, la première occupation du site et les peintures murales pourraient bien être antérieures