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This article presents a study of 52 metallic artifacts made of gold and copper from the archaeological sites of Tamtoc and Rancho Aserradero, both located in the Huastec region of San Luis Potosí, Mexico. These objects served both utilitarian (e.g., needles, fish hooks, and axes) and ornamental (e.g., rings, beads, and bells) purposes. The objective of this paper is to provide a detailed description of the artifacts, present the results of an elemental, non-invasive, and non-destructive in situ analysis performed using X-ray fluorescence, reconstruct the manufacturing processes, and compare these findings with similar objects from other contemporary Mesoamerican regions. This research generated new data and knowledge about the use of metals and alloys in the Huastec region, the technological and cultural decisions behind the creation of these objects, and the exchange networks that facilitated their distribution. The examination of the 52 pieces revealed significant diversity in morphology and elemental composition, which limited the cultural interpretations due to the small sample size. Nevertheless, our results indicate that the studied sites were part of an extensive exchange network with access to metallic objects from the central and western regions of Mesoamerica, as well as Oaxaca and/or Central America. [ABSTRACT FROM AUTHOR]

Mercury concentration measurements were compiled from 72 sites located throughout seven departments of Colombia using field information gathered from 2016-2021 by Pure Earth, an international non-profit organization, and secondary information from previously conducted studies. These measurements and other data such as type of contaminated resource (water, soil), resource use (fishing, agricultural, residential, and industrial), estimated at-risk population, and permissible contamination limits were entered into Pure Earth's Toxic Site Identification Program (TSIP) database. Using information from the TSIP database, the Blacksmith Index, a contaminated site intervention prioritization index, was calculated for all 72 sites. After applying exclusion criteria to the sites for this study, the results show that approximately 55,095 people are affected by mercury contamination in 44 sites. Of these study sites, the site with the highest Blacksmith Index value and therefore, the highest health risk due to mercury contamination, is La Bocana in the department of Valle del Cauca. [ABSTRACT FROM AUTHOR]

Los países de China, Estados Unidos, India, Rusia, Japón y Alemania emiten el 60% de los gases de carbono del mundo que provocan el cambio climático y la degradación de la biodiversidad. Al mismo tiempo, estos países y las empresas que crearon buscan obtener ganancias económicas considerables de la “Energía Verde” como reemplazo de la dependencia de la economía basada en el carbono. El gobierno estatal y las políticas empresariales promueven la extracción de metales como el oro, el tántalo y el litio, elementos clave necesarios para apoyar el desarrollo de reemplazos eléctricos para máquinas a base de petróleo como los automóviles. El problema explorado en este artículo es que, si bien la “energía verde” es un paso positivo hacia la reversión de los efectos adversos de la economía basada en el carbono, se causan daños catastróficos al medio ambiente y a los pueblos indígenas. La consiguiente explotación minera y de otros recursos del “reverdecimiento” destruye y contamina directamente el medio ambiente al mismo tiempo que fuerza violentamente la expulsión de los pueblos indígenas de sus territorios o incluso mata a miles de personas. La democratización de la minería y la explotación de otros recursos dentro de los territorios ancestrales de los pueblos indígenas es esencial y debe convertirse en el nuevo estándar, un estándar basado en obtener el consentimiento de los pueblos indígenas afectados. El autor presenta un plan de energía verde para mediar en las relaciones entre naciones indígenas, empresas y estados. La extracción y explotación de recursos de “energía verde” es una actividad económica dominante pero destructiva en la República Democrática del Congo (RDC), el segundo estado más grande del continente africano. La República Democrática del Congo ilustra el problema como la mayor fuente de tantalio de “energía verde”, un “metal refractario” extraído con litio esencial para producir condensadores, chips de computadora y semiconductores utilizados en tecnología eléctrica. El tantalio y el litio se extraen principalmente de los territorios de las naciones indígenas con consecuencias desastrosas. [ABSTRACT FROM AUTHOR]

With the realization of the role of exosomes in diseases, especially cancer, exosome research is gaining popularity in biomedical sciences. To understand exosome biology, their labelling and tracking studies are important. New and improved methods of exosome labelling for detection and tracking of exosomes need to be developed to harness their therapeutic and diagnostic potential. In this paper, we report a novel, simple and effective method of labelling and detecting exosomes using Oil Red O (ORO), a dye commonly used for lipid staining. Using ORO is a cost effective and easy approach with an intense red coloration of exosomes. Further, the issues faced with commonly used lipophilic dyes for exosome labelling like long-term persistence of dyes, aggregation and micelle formation of dyes, difficulty in distinguishing dye particles from labelled exosomes, and detection of large aggregates of dye or dye-exosome, are also resolved with ORO dye. This method shows good labelling efficacy with very sensitive detection and real-time tracking of the cellular uptake of exosomes. [Display omitted] • A new protocol for exosome staining is established. • Exosome were stained using Oil Red O a commonly used laboratory reagent. • This method shows negligible aggregates with exosomes or dye. • Dye concentration required to stain exosomes does not stain any cell components. • Uptake of the stained exosomes by live cells can be easily detected. [ABSTRACT FROM AUTHOR]

During the last decades, mexican mining registered an unusual geographic expansion. This situation led to the simultaneous outbreak of dozens of social conflicts. In this context, this article analyzes the relationship between the financialization of precious metal mining and the origin of the social conflictivity around this activity. The approach to this dimension is carried out from the case of the Cerro Jumil gold project, located in the state of Morelos, Mexico, whose distinctive feature is its eventual location in the vicinity of the Archaeological Zone of Xochicalco, included in the list of Unesco World Heritage List. Archive work was done in repositories with financial information and different field trips. It is shown that in the study area, the area concessioned to mining increased 3,181 % during the period 2002-2009, motivated by financial speculation and the permissiveness of the State, that led to the outbreak of a strong social conflict in 2012. It is concluded that the case study shows the need to modify mining legislation, with the understanding that only in this way the possibility to regain control of their territory will be opened for local communities. [ABSTRACT FROM AUTHOR]

The aim of the study is to demonstrate that the biotinylated 19 base oligonucleotide probe of the gag gene H1Gag1584 can be used as a molecular recognition element for the detection of HIV-1 proviral DNA, in two electrochemical detection systems of free laber. Two free leber electrochemical detection systems were evaluated: an impedimetric DNA genosensor using a self-assembled biotin monolayer (SAM) and a voltammetric DNA genosensor by modifying a new epoxy graphite transducer with graphene oxide. The results obtained in this study showed that the biotinylated 19-base oligonucleotide probe of the gag gene H1Gag1584 can be used as a molecular recognition element for the detection of HIV-1 proviral DNA, in two electrochemical detection systems of free labels. [ABSTRACT FROM AUTHOR]

Mineralogical characterization is a fundamental stage when designing and implementing metallurgical extraction processes. In the case of gold mining, knowing how the metal forms and its mineralogical associations is an essential tool when minimizing losses or designing processes. Northeast Antioquia has distinguished itself as one of the main gold producing areas in Colombia. Here, a characterization of different samples from this Colombian region was done using XRD, XRF, QUEMSCAN, SEM-EDX, fire assay, conventional cyanidation, and froth flotation tests. The analyses performed classify this deposit as "high grade," with values up to 81 g/t of gold. Quartz is the most common mineral, followed by muscovite, pyrite, and potassium feldspar. Gold was found in the form of electrum associated with sulfide minerals, therefore, a conventional flotation process is proposed, with an average recovery of 90%. [ABSTRACT FROM AUTHOR]

The National Office of Mineral Resources of Cuba keeps the archives that contain the unpublished and not systematized information of the small gold mining works carried out during the neocolonial stage in the central part of the Sierra Maestra. The processing of this information has revealed existence of dozens of important mining preserves with hundreds of mining concessions, from which significant amounts of copper, gold and silver were extracted; and has provided new data on the types of mineralization and their quality that constitute direct indexes to explore. These prospects have a great interest in the current economic context, so their perspectives must be evaluated. [ABSTRACT FROM AUTHOR]

In this work, the effect of the agitation speed on the thiourea kinetics with thiourea of gold-floated minerals, the concentration of thiourea (TU) that achieved the greatest recovery of gold from its floated concentrates compared with cyanide was determined, along with the kinetic model that controls leaching with thiourea. For this, a "Suction tube" type Baffled reactor is used with mechanical agitation by means of a vane type impeller. The parameters analyzed were: percentage of solids (15%); TU concentration (1, 3, 6, 9, 12 g / L); stirring speed (420, 490, 560, 700 rpm); reaction time (4 hours); effective reactor capacity (27.1 L). An atomic absorption spectrophotometer is estimated to determine the gold concentration. It was determined that the thiourea concentration of 9 g / L was the one that produced the best gold recovery results. The thiourea leaching process adapts to the kinetic diffusion model through the ash layer as a controlling stage. Thiourea, as a leaching agent of the Au concentrate, has a lower percentage (1.74% less) of recovery of this metal than with cyanide during the leaching process at 240 minutes of stirring at a stirring speed of 700 rpm. [ABSTRACT FROM AUTHOR]

Oil red O (ORO) is a commonly used dye for the tissue staining, which recognizes nitroglycerin and cholesterol esters. In this paper, we describe an unexpected finding that ORO can be fluorescently lighted up upon meeting dsDNA with emission peak localized at 600 nm, although it almost does not fluoresce by itself. This property triggered us to test its potential as a dsDNA fluorescence probe. The interaction of dsDNA and ORO was demonstrated by spectral and thermodynamic analysis and several other means. The fluorescence of ORO was gradually increased following the addition of dsDNA, which showed linear response toward dsDNA in the concentration range from 0.02 to 0.64 mg/mL with a detection limit of 0.69 μg/mL. Moreover, ORO showed excellent selectivity when testing with a variety of dsDNA-like biomolecules. Besides, ORO resisted photobleaching and worked very well under biological background. Altogether, we propose here a new nucleic acid lighting up fluorescence probe for double stranded dsDNA detection. • The fluorescence and dsDNA binding nature of ORO have not yet been documented before this study. • ORO has several advantages such as resistance to photobleaching, rapid response and low cost. • This finding provides both an approach for dsDNA detection and a model for dsDNA-dye supramolecular chemistry. [ABSTRACT FROM AUTHOR]

The knowledge of the kinetic control mechanisms of gold leaching in real process conditions is crucial for the correct process design and plant operation. This research evaluated the kinetic control mechanism on the gold leaching with cyanide in alkaline media from a previously floated ore. Before the leaching, a pre-treatment with sodium hypochlorite was carried out to eliminate remaining reagents from the flotation process. After the pre-treatment several leaching experiments were conducted keeping constant the pH, temperature and aeration rate, meanwhile the agitation velocity and cyanide dosage were varied. The analysis of leaching kinetic profiles indicated that the control of the reaction corresponds to the mass transfer in the ash produced by the reaction with two resistances to the leaching process. Furthermore, the analysis was complemented with scanning electron microscopy and x-ray dispersive energy (SEM-EDX) measurements confirming that the leached ore surface do not contain detectable levels of gold. [ABSTRACT FROM AUTHOR]

This research was mainly focused on performing analysis of arsenic in stream sediments, soils and rocks in an area at the confluence of Piranhas and Seridó Rivers in Rio Grande do Norte state, northeast of Brazil. The methodology of collecting and preparing samples for analysis followed international standards of quality (QA / QC) and was carried out in conjunction with the Canadian Company Eldorado Gold Corp., through its Brazilian subsidiaries. Arsenic is present in concentrations above reference values in an area that is located upstream of the Oiticica Dam, which is under construction and has a storage capacity of 556 x 106/m³, and will supply a large portion of the population from the State semiarid region where live more than one hundred thousand people, considering only municipalities directly affected. [ABSTRACT FROM AUTHOR]

The leaching of gold with thiosulfate in an ammoniacal media was studied. The concentrates contained 44.1 and 71.4 (g/t) of gold respectively, the main mineralogical species present correspond to sphalerite (ZnS), chalcopyrite (CuFeS2), galena (PbS), pyrite (FeS) and gangue. The tests were carried out in a stirred reactor, with a maximum contact time of 50 hours. The parameters pH, thiosulfate and Cu (II) concentration were studied. The gold dissolved mostly at pH 10.5; 74.1 (g/l) of thiosulfate and 3.18 (g/l) of cupric ion, with gold recoveries of 84% for the low-grade concentrate and 82% for the high grade. [ABSTRACT FROM AUTHOR]

La Herradura mine in Sonora is one of the most important gold districts in Mexico producing more than 5.5 million ounces of gold over 17 years. It is part of an orogenic gold deposits belt with a northwest-southeast direction for 300 km long and 50 km wide. The mineralization consists of veins and quartz networks veinlets formed in a brittle-ductil geologic environment and it is hosted in Proterozoic quartz-feldspar gneisses. The ore bodies, defined by a 0.3 g/t Au cut-off grade, have tabular forms up to 1 km in length, 1 km in depth and 100 m in width. The visual control for mineralization is the abundance of quartz veins and veinlets, and a persistent sericitic hydrothermal alteration. Different techniques were used in this work with special focus on the Mineral Liberation Analizer (MLA) program to prove the possibility of predicting recoverable gold in the mine for the primary sulphide zone. Three geometallurgical zones (Zones A, B and C) were defined by ore composites and gravimetric concentrates from the same composites. Modal composition of the concentrates is quartz, feldspar and muscovite (sericite), and a metallic mineralogy of pyrite, sphalerite, galena, magnetite, gold and tellurides of gold and silver. Gold is identified as inclusions in pyrite or in gangue minerals like quartz, albite, orthoclase or ankerite, as well as coating pyrite crystals. The gold composition is electrum with 74% Au and 26% Ag; the presence of petzite (Ag3AuTe2) and stutzite (AgTe) were also identified. Recovery constants were calculated for each geometallurgical zone, which were introduced to the resource model of more than 14 million ounces of gold, indicating that error range in recoverable gold is less than 4% for Zone A, 6% for Zone C and 13% for Zone B, in relation with gold recovery calculated with traditional methods. These results could be acceptable to applicate this methodology to La Herradura deposit. The most important error range in the Zone B is interpreted as due to a nugget effect, which is very common in such mineral deposits. It is also concluded that the secondary milling process currently incorporated to the metallurgical plant is probably unnecessary, so its removal would result in a significant saving in energy and therefore in the economy of the mine. [ABSTRACT FROM AUTHOR]

This article studies financial crises and their impact on the main types of financial investment. Specifically, the objective of this study is to analyze the impact that financial crises generated in purchase of jewelry at Ouro Scheffer. It was therefore necessary to first revise the concept of main types of investment in variable income and fixed income, as well as a history of gold, and to analyze the main financial crises. Applied and quantitative research was then carried out with an analysis of three temporal series: gold, Ibovespa and Ouro Scheffer's jewelry sales revenue. The results found that the main financial crises of 1999 and 2008 had an impact on the jewelry sales temporal series. It was also possible to determine that these crises generated an impact on the gold and Ibovespa temporal series. [ABSTRACT FROM AUTHOR]

In the rocky massif where the Oro Descanso underground mine is located, an assessment was made of the physical-mechanical properties of rocks, cracking and blocking, in order to propose safe tillage measures for underground mining excavations using appropriate empirical methods. From the evaluation made it was concluded that the massif is composed of areas of rocks of different quality: good, fair and poor. It is proposed for the area of good quality to work excavations with complete advance, of free length 1.0-1.5 m, using in the crown the support of cemented anchors of diameter 20 mm, length 3 m and spaced 2.5 m and apply concrete released 50 mm thick. For the zone of bad and regular quality, it is suggested to work in stepwise progression, of free length of 1-3 m and after each blasting, to install in the crown, cemented anchors of diameter 20 mm, length 4-5 m and spacing 1-2 m, placing on the sides metallic mesh, with concrete cast 50-150 mm thick. [ABSTRACT FROM AUTHOR]

This research experience arises from the need to consider the importance and usefulness of studying gold in the Field of Science Teaching within the educational context of teaching chemistry. The general purpose is to characterize the contributions of the identity heritage that may be established from the intercultural tension points between ancestral knowledge and the scientific knowledge on the case of gold in Colombia among middle school students. The research is qualitative in nature, and it follows the social-critical paradigm. It involved ten-grade students from a school in Bogotá, who took part in a number of purposeful activities developed through a didactic unit. The experiences were documented in video and audio, and the theory related to intercultural education, sociology of science, knowledge ecology, Epistemologies of the South, Heritage Teaching, and Science Teaching was considered for the analysis. The findings made it possible to identify in students the existence of internal and external intercultural tensions regarding the aspects of social events, western culture, ancestral knowledge and scientific knowledge, and their relationship with heritage identity levels: absent, latent, patent and extended for the case of gold. [ABSTRACT FROM AUTHOR]

This work presents the mineralogical characterization of three ore bodies gold located in the northeast of the department of Antioquia, Colombia, which are currently benefited with mercury. Five tests were carried out on three gold deposits: determination of mineral species and analysis of false color images by QEMSCAN®; identification and quantification of gold by FE-SEM; fire analysis and cyanidation tests. The results by QEMSCAN showed that the ore bodies are mainly composed of quartz, potassium feldspar, muscovite and pyrite. The results by FE-SEM showed that gold is mainly found as nanoscopic nodules scattered in muscovite and quartz. Another amount of gold is in the form of electrum. The fire assay showed that the amount of gold was between 1 and 34 g/t and the cyanidation tests showed that it is possible to extract the gold up to 80% only with grinding and direct cyanidation without any other treatment. These results can be the basis for a proposal with alternative metallurgical methods that allow the extraction of gold without the use of mercury. [ABSTRACT FROM AUTHOR]

Mining is considered one of the economic activities that most produces pollution to water sources and soils, in addition to being the exploitation of a finite resource in which they generate sterile residues that end up as rubble or discharges in rivers. The responsibility and awareness that companies and universities have taken on the damage caused has made it innovate and invest in technology that improves extraction and generates a system where materials can be produced without using chemicals such as cyanide and mercury. This article presents a work carried out in the mine "Sociedad Minera la Elsy en Vetas, Santander" in conjunction with a research group to design a sustainable effective extraction system and shows the study carried out on sterile waste for use them as aggregates for construction. [ABSTRACT FROM AUTHOR]

In the context of the current commodity boom, informal and illegal mining have become acute challenges to the Peruvian state. This article documents and explains the state's response to these challenges. After a stage of inaction (2004-2008), the Peruvian state initially reacted with a disarticulated response (2008-2011) before mounting a more coherent and organized response (2011-2015). Although the state's response to the challenge has been limited, it is has nevertheless resulted in an observable increase in state capacity. We propose that this phenomenon is better explained by factors external to the state (international pressures and domestic demands) rather than by processes triggered from within. [ABSTRACT FROM AUTHOR]

This study has as its main objective to develop an analysis of decision making under uncertainty using the real options application in the evaluation of investments in mining projects. It is also proposed to study the behaviour of gold prices, for the specific case of Peru, using historic prices and based on the commodity prices process. The Ornstein-Uhlenbeck model has been used for this. The main result is that to evaluate projects using the real options approach allows to evaluate -in their real magnitude- the financial benefits associated with an investment project, as it takes into account the trinomial of profitability-risk-flexibility. The assessment method using real options makes it possible to structure strategic thinking. [ABSTRACT FROM AUTHOR]

The Peruvian government is attempting to implement a formalization plan to deal with the chaotic expansion of small-scale mining activities in the Amazon. However, this plan has been contested, delayed and halted by local miners. Why exactly has it been so hard for the government to enforce a formalization plan in Madre de Dios? This article aims to answer this question by analysing both government efforts to establish control over the region and the challenges it faces in enforcing its formalization plan. It is argued that current resistance to and conflict over the formalization process in Madre de Dios reveals a state governance problem due to the region having been historically governed as a zone for exploitation rather than for social and economic development. Similarly, the analysis highlights the absence of major corporations through which the state can establish a basis for governance, as in other parts of the country. [ABSTRACT FROM AUTHOR]

The main objective of this work was to determine the photocatalytic effect of the TiO2mod-FA and TiO2mod- FA-Au nanomaterials on Hela and CHO line cells. Titanium oxide (TiO2), a substance with possible and future use on the treatment of different cancer types, is analyzed due to its possible cytotoxicity effects when it is exposed to ultraviolet light. The level of cytotoxicity of the nanomaterials in presence and absence of ultraviolet light was determined by the cytotoxicity detection kit. The results showed that the nanomaterials under the established parameters are toxic on Hela cells but non-toxic on CHO cells. The effect of the TiO2mod-FA-Au nanomaterials exposed over 40 minutes to ultraviolet light showed 78% of cytotoxicity on Hela cells, being the highest percentage between the nanomaterials. The selectivity over cancer cells was the main finding that could become a possible path for cancer treatment with lower secondary effects on human health. [ABSTRACT FROM AUTHOR]

This paper takes four frameworks for understanding linguistic politeness (Brown and Levinson, Watts, Terkourafi, Hall) and tests each on the same corpus to see whether they yield results that are useful and/or in keeping with the other information we have about the material. The corpus used consists of 661 polite requests made in letters by a single Roman author, Cicero. The results demonstrate first that politeness theories are helpful as explanatory tools even in dealing with very well-known material, and second that no one theory is best: different theories are more and less useful in answering different questions about the data. It is therefore suggested that the use of multiple frameworks will provide the best understanding of the data. [ABSTRACT FROM AUTHOR]

This article shows the main experimental results related to measuring dielectric properties of Pyrite ore mineral samples as a function of temperature, and their effect on the heating behavior of the samples. It was found that the real, ϵ'(T), and imaginary, ϵ''(T), components of permittivity are strongly dependent on temperature. The model that best fitted experimental data for ϵ'(T) and ϵ'(T), was a Gaussian correlation, reaching R2 values over 0.995. Besides, and under certain conditions, it was possible to roast the mineral even better than with an electric furnace, while requiring less processing time (about 77.5% less) and with lower electrical energy consumption (about 80.8% less). Additional exploratory tests revealed that microwaves can be used to smelt a roasted mineral ore with time reductions of about 90%, while keeping recovery margins above 95%. Next stages of research should be directed to using a single mode applicator for processing higher volumes of mineral at pilot plant scale. [ABSTRACT FROM AUTHOR]

Oil Red O is a fingermark reagent that is useful for developing greasy fingermarks. Classic Oil Red O formulation is based on methanol-water solution. The use of solvent can be harmful to the forensic practitioner and the environment. Moreover, solvent can destroy hand writing and biological traces. In this paper a new solvent-free Oil red O deposition method have been proposed. Experimental method is based on Oil Red O deposition from a gas phase in reduced pressure conditions. 1728 split, greasy fingermarks deposited on paper have been developed with the new method and a benchmark one. The development results have been compared. The general performance of the new method has been found inferior to the solvent based formulation. However, in most cases both methods were comparable. This shows that the experimental method could be a possible alternative to the classic one in the cases where drawbacks connected to the solvent use are unacceptable. Even though, presented results are promising, more research and optimization is necessary, before the new method can be included into the forensic expert toolbox. [ABSTRACT FROM AUTHOR]

This research article, supported by Universidad Industrial de Santander (Vicerrectoría de Investigación y Extensión), shows the results achieved after using the electromagnetic cavity of a microwave oven and a temperature measurement system, to heat a mineral sample from the mining district of Vetas, in order to see if it was possible to induce a cheaper processing. A factorial design of experiment (DOE) was used to observe the effect of the microwave power, the exposure time and the sample's mass. It was found that an energy consumption reduction of 81.7%, and a time reduction of 75%, were possible to achieve while maintaining the recovery margin at 90% of the achieved with a traditional roasting, at lab level. Thus, it can be concluded that, at least for this ore, microwave roasting of the sample is viable at this scale. Moreover, if a better applicator were to be used, the benefits could be enhanced even more, so it is encouraged as a next step. [ABSTRACT FROM AUTHOR]

The aim of this work is to compare the economic performance of three important gold producing countries --Australia, Peru and South Africa-- and of three important oil petroleum producing countries -Iran, Mexico and Saudi Arabia- during 2003-2012. The indicators selected were: rate of change in the Gross Domestic Product (GDP), change in per capita real GDP from 2003 to 2012, changes in the unemployment rate from 2003 to 2012, and annual average inflation rate of the period. The best average performance of the economies that make up the group of gold-countries comes from the last three indicators. The political and social instability of Iran and Mexico has played against the group of oil-countries during the period. [ABSTRACT FROM AUTHOR]

In this article we investigate the role of gold as hedge of the euro-dollar exchange rate during the period 1999-2011. For this, it was used an EGARCH (2,1,1) model applied to daily data. The results show that gold has served as an useful hedge against the exchange rate risk of the investments in dollar-denominated assets carried out by the inhabitants of the euro-zone. During the period of the sample, gold was inelastic with respect to the euro-dollar exchange rate both in the short-run and in the long-run. [ABSTRACT FROM AUTHOR]

The work of William Lewis (1708-11781), a physician converted into chemist and metallurgist, was characterized by a deep practical approach; he carried on research on gold and its applications, the conversion of glass into porcelain, black dyes, and two new materials brought from America, platinum and its alloys and Americanpotashes. He was one of the first chemists to introduce titrimetry as a method of chemical analysis. [ABSTRACT FROM AUTHOR]

This text relates the history of the arrival of alluvial mining to the Middle Caquetá region (Colombian Amazon). It is narrated from the experience of one of the leaders of the Multiethnic Community of Quinché-Metá, formed by indigenous peoples from several ethnic groups and homesteaders, which aimed to organize as a multiethnic Resguardo (legally constituted indigenous territory) at the beginning of the 21st Century. The text begins with the narration of this organizing process and what had been achieved. Then it tells about the arrival of the mining rafts, together with the guerilla and drug dealers, and how it quickly eroded the process and the abuses and killings escalated. The text also tells about other experiences with gold extraction in the Taraira River. It concludes with the “reconquest" of the region by the Colombian army and how ten years after, in 2012, once again the miners are returning to the Caquetá River. [ABSTRACT FROM AUTHOR]

This article aims to reflect on the use of law in spaces of (post)colonial domination from the legal framework of large scale gold mining in Colombia. This problem arises from the context of the extractive industry that has expanded in recent years in Latin America, seeing it as a manifestation of the myth of development and as a continuation of the legacies of colonialism. The growing presence of transnational mining companies under the auspices of local governments has been a feature of the processes of (neo)colonization, in which Colombia has been no exception. It seeks to reflect on the role of the rule of law as manager and intermediary of the transnational corporations and international economic organizations government and on the role played by the law in the establishment of a new mining regime and a new developmental state. [ABSTRACT FROM AUTHOR]

The liver, due to its central role in the regulation of metabolism and multiplicity of its other functions, is exposed to a high number of pathogenic factors. Non-Alcoholic Fatty Liver Disease (NAFLD), manifested mainly by changes in liver's lipid profile, represent one of the most frequently occurring liver pathology, that is often underestimated at an early stage of its development. The pathogenesis as well as the treatment of NAFLD has not been fully established yet. The difficulty associated with this arises from the need to detect very subtle changes. With regard to fulfilling these expectations, from all available research methods vibrational spectroscopic imaging techniques attract special attention, as they possess a great potential to detect even minor variation in chemical composition of the sample. The specificity of infrared imaging and Raman mapping along with their complementarity provides the ability to obtain comprehensive information on the molecular level. Here we present an approach for the study of liver tissue based on the simultaneous application of vibrational spectroscopic imaging and multirivate data analysis combined with histochemical staining. [ABSTRACT FROM AUTHOR]

We studied the synthesis of colloidal catalysts of Au, Ir and Au-Ir, supported on TiO2. The solids obtained were characterized by X ray diffraction (XRD), temperature programmed reduction (TPR), nitrogen physisorption, chemisorption of hydrogen and transmission electronic microscopy (TEM). The catalytic activity was evaluated in the selective hydrogenation of acrolein in gas phase. The results of characterization indicated that the metal particles were not completely reduced, so it was necessary a subsequent heat treatment of reduce at 773K. This treatment did not affect the particle size obtained by transmission electron microscopy. The addition of iridium to gold increased the dissociation capacity of hydrogen with respect to the monometallic gold catalyst and improved catalytic activity in the selective hydrogenation of C= O group of acrolein. [ABSTRACT FROM AUTHOR]

This study investigates the importance of the bullroarer cult in Cuban orisha worship. Though the cult was one of the most feared collectives of precolonial Yorubaland, carrying out the executions of criminals and witches on behalf of the state councils, the cult that came to be recreated in Cuba after the transatlantic separation took on a quality that was more devotional, though equally secretive. Given that so much change has occurred among the bullroarer cults in Cuba and Yorubaland since the termination of the slave trade, the conspicuous links between the two cults have all but disappeared. The case will be made however that, by lending particular attention to the bullroarer and other accouterments of the cult in Cuba, links can be re-established that explain the persistence of the cult in Cuba and demonstrate the ways in which ironically this emblematic sounding instrument of the cult is often constructed in a manner that actually "mutes" the instrument. [ABSTRACT FROM AUTHOR]

The history of gold mining in Cuba has been described in numerous published works; however, it has not been systematized in accordance with the socio-economic developments of the island. Several classifications and conceptual models have been presented on the gold metallogeny in Cuba, but they are not clear and do not plainly reflect the essential attributes that characterize gold mineralization on the island. The aforementioned circumstances justified a historical-descriptive research project based on an exhaustive literature review, and the analysis and interpretation of the available information. Gold mining on the island extends over three historical stages: colonial, neocolonial and revolutionary. Four main metallogenetic episodes for gold formation can be distinguished on the island of Cuba: (i) an Aptian-Campanian stage of mineralization with low- and high-sulfidation Au-Cu porphyries, Au skarns and Au-Ag epithermal deposits; (ii) a late Campanian-early Danian episode that hosts orogenic-type gold mineralization and listvenites; (iii) very prolific Danian-middle Eocene gold mineralization in listvenites in Central Cuba and in Palaeogene volcanic island arc rocks in the southern part of eastern Cuba; and lastly, (iv) an Oligocene-Recent mineralization stage in which surface gossans are produced by the oxidation of sulfide ores and placers. The future of gold mining in Cuba is very attractive, but at a small to medium scale. [ABSTRACT FROM AUTHOR]

Abstract: Nutrient availability is one of the major non-genetic factors determining embryonic growth and larval or fetal size. Due to the high human consumption of blood lipid regulators, fibrates have recently been reported as pollutants in rivers. Our study investigated the developmental toxicity of fibrates in zebrafish. Treatment with micromolar concentrations of clofibrate or gemfibrozil induced an embryonic malabsorption syndrome (EMS) with very little yolk consumption, resulting in small-sized larvae. This effect was reversible on removing the drug from the water. Clofibrate delayed hatching time and decreased the amount of oil red O lipid staining in the vasculature. It also induced higher density, round-shaped neuromuscular junctions associated with disorganization and less striation of muscular fibers, and pericardial edema, as well as impairing thyroid gland morphogenesis. acox1, apoa1 and mtp hybridization transcript signals were not affected in the yolk syncytial layer (YSL) after clofibrate exposure. Di-(2-ethylhexyl)-phthalate did not slow down yolk resorption, whereas brefeldin A induced EMS. These findings suggest that the inhibition of yolk sac resorption on exposure to fibrate is not at a pre-translational level or peroxisome proliferator-activated receptor alpha dependent and may be due to an inhibition of the YSL constitutive cell secretion. The effects of fibrates and the potential bioconcentration in eggs as well as the additive action of structurally related toxicants warrant an evaluation of the developmental impact of these compounds after long-term exposure at environmentally relevant concentrations. Fibrate-induced EMS in zebrafish seems useful for studying the morphogenetic consequences of impaired nutrient availability during the early stages of vertebrate development. [Copyright &y& Elsevier]

Although mining is at present a significant source of foreign currency flows to Peru, it went through times of crisis when metal quotations dropped. Many international mining majors weathered the crises with the financial backing of their parent companies or financial multilaterals, and their operative economies of scale. In the wake of the crisis, some small and intermediate mining companies closed their operations, leaving behind a negative impact of their communities and a degraded environment. Yet, other companies, thanks to the commitment of their shareholders, workers and local banks, introduced a number of initiatives to negotiate the crisis. The story of Gold Land Mining illustrates the case of those companies that managed to survive during very dire times. [ABSTRACT FROM AUTHOR]

For approximately 150 years, Africans fled enslavement on Southern plantations and lived autonomously in Florida, using discrete African art forms, traditions, and sensibilities in their modes of communications, rituals, sub- sistence strategies, and battle plans to prosper and achieve and sustain their freedom and autonomy. This article reconstructs the ways cultural forms and practices, such as àrokô, nsibidi, tusona or sona (ideographic writing systems), and mmomomme twe and ogede (incantations), functioned in these self-emancipated Africans' stratagems to escape from Spanish, British, and American plantations; thrive socially and economically in the autonomous settlements they established; elude recapture; and defeat their former enslavers and other foe militarily despite their adversaries' incessant onslaughts, advanced artillery, manpower, and economic advantages. [ABSTRACT FROM AUTHOR]

During the 19th century, different types of illegal trade became widely spread activities all over the territory that today constitutes Colombia. Given that government policies affected illegal trade, the purpose of this article is to examine how the configuration of 19th century State had repercussions on the development and persistence of opportunities for smuggling. In order to achieve this objective, two complementary theoretical positions regarding State management are analized. On the one hand, the Neoinstitutionalist theory, and on the other, opportunity surplus. Finally, as an exercise meant to evaluate the proposed theoretical approaches, the case of gold smuggling in Antioquia during the first half of the 19th Century is analyzed. [ABSTRACT FROM AUTHOR]

The Quesigua epithermal occurrence is formed for quartz veins with base metals and gold, and it is hosted in cretaceous volcanic rocks from Téneme formation. Crystalline quartz textures, base metal rich and adularia-sericite host rock alteration are the principal features. The results of paragenetic, fluid inclusions, and sulfur stable isotope studies indicate an deep epithermal low-sulfidation or intermediate sulfidation 34 origin. d S data suggest a magmatic provenance for pyrite, sphalerite and galena. In addition, salinities are low (2,57-9,86 wt % NaCl equiv.) and the formation temperatures are around 230-270 °C. The emplacement occurs at 350-600 meters beneath the paleo-surface. Quesigua occurrence is the first low sulphidation epithermal system documented in Moa-Baracoa region. It shows that epithermal mineralization style may be found in deeply eroded volcanic arches. [ABSTRACT FROM AUTHOR]

Hoy en día, el oro se utiliza ampliamente para dispositivos eléctricos y electrónicos debido a su alta estabilidad química y alta conductividad, en consecuencia, su consumo ha aumentado exponencialmente. Durante la explotación minera se generan residuos de oro, lo que produce una cantidad considerable de aguas residuales y sedimentos que contienen oro, generando impactos negativos en el medio ambiente. El oro presente en los sedimentos se puede extraer eficazmente en soluciones ácidas, proporcionando un recurso importante de recuperación de oro. Es fundamental encontrar un método efectivo para la recuperación de oro a la vista de la protección del medio ambiente y la plena utilización de los recursos naturales para la extracción de oro. Se han empleado técnicas para la recuperación de oro; (I) adsorción por resina de intercambio iónico (II) extracción por solvente y (III) precipitado de oro reducido por reactivos. Sin embargo, estos procesos de recuperación actuales requieren mucho trabajo y tiempo a un alto costo. En este sentido, se propuso en este trabajo, generar un adsorbente de origen tánico obtenido a partir de residuos forestales donde se emplea la corteza de pino, como una clara alternativa para la recuperación de oro presente en los sedimentos residuales. Una vez extraídos los taninos presentes en la corteza de pino, se mezclan con el agente reticulante en un matraz de fondo redondo de tres bocas de 200 ml y se agita a ebullición. Las pruebas de adsorción para oro se realizan en las siguientes etapas: se toman 10 mL de soluciones de concentración conocida de oro y se mezclan con 10 mg de adsorbente seco, las muestras se agitan hasta alcanzar el equilibrio. Después de la adsorción, las muestras se filtran inmediatamente y se mide cuantitativamente usando espectroscopia de absorción por llama. El adsorbente preparado fue efectivo para la adsorción de oro en soluciones de concentración conocida, mostrando porcentajes de adsorción entre 95-98%. [ABSTRACT FROM AUTHOR]

Introduction: Breast milk is essential for human development, but it may contain toxics derived from environmental pollution, especially in mining areas. Objective: To assess the prevalence of mercury contamination in breast milk and factors associated with its transfer to nursing mothers living in municipalities with gold mining. Materials and methods: We conducted a cross-sectional study with 150 nursing mothers in four municipalities of Antioquia (El Bagre, Segovia, Remedios and Zaragoza) with a mining tradition. We surveyed these mothers to obtain information on their sociodemographic, occupational and environmental factors related to mercury, and we took breast milk, urine and hair samples. We calculated mercury level averages and the contamination prevalence per municipality. Results: Mercury average in breast milk was 2.5 (± standard deviation: 9.2) mg/L. The prevalence of mercury contamination in samples with a high level of mercury was 11.7%. Conclusion: This study shows that there is a serious problem of mercury contamination in gold mining regions of Antioquia, with significant involvement of the most vulnerable population. [ABSTRACT FROM AUTHOR]

Introduction: Currently it is proposed to use plastic fittings for casting metal-based alloys (Co- Cr) to obtain satisfactory results at lower costs. However, this has been questioned by the difficulties in achieving a close adaptation between fittings, and additionally by its affect on the bone-implant interface through such phenomena as corrosion and galvanism. Objective: To evaluate in vitro the electrochemical behavior of two alloys (Au and Co-Cr) used in the rehabilitation of dental implants. Methodology: Four groups of implants: 1. MIS Implants, 2. Neodent implants, 3. Au MIS pillars, 4. Co-Cr Neodent pillars) were placed on acrylic specimen supports for analysis in an electrochemical cell with artificial saliva to determine: 1. corrosion by pitting and 2. potential corrosion of some of alloys. Results: No statistically significant differences were found (t test) among any of the brands of implants or with the Au and Co-Cr pillars for density values (p = 0.067, p = 0.096), (p = 0.134) and potential for corrosion (p = 0.690, p = 0.705), (p = 0.778, p = 0.779) respectively. Moreover, the corrosion rate values did show statistically significant differences in the two brands of implants and for the Au and Co-Cr pillars, respectively (p = 0.019, p = 0.026), (p = 0.000, p = 0.001). Conclusions: The behavior analyzed regarding galvanic corrosion of the couplings between Ti and the alloys of Au and Co-Cr was favorable compared to the reference value of 0.5 V. It indicates that this type of coupling between alloys allows for an implant-restoration interface that is more passive, and this may reduce bacterial colonization and possible corrosion in the union. [ABSTRACT FROM AUTHOR]