scholarly journals Spatial and Temporal Controls on the Distribution of Indium in Xenothermal Vein-Deposits: The Huari Huari District, Potosí, Bolivia

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 304 ◽  
Author(s):  
Lisard Torró ◽  
Joan Melgarejo ◽  
Laura Gemmrich ◽  
Diva Mollinedo ◽  
Malena Cazorla ◽  
...  
Keyword(s):  
Iron Sulfide ◽  
Hydrothermal Fluids ◽  
Central Position ◽  
Strong Positive Correlation ◽  
Formula Unit ◽  
Vein Mineralization ◽  
Critical Metal ◽  
Coupled Substitution ◽  
Moderate Negative Correlation ◽  
High Concentrations

The Huari Huari deposit, Potosí Department in SW Bolivia, hosts polymetallic stratiform and vein mineralization of Miocene age with significant concentrations of the critical metal indium (In). Vein mineralization records document early crystallization of quartz and cassiterite followed by prominent associations of sulfides and sulfosalts. The earliest sulfide was arsenopyrite, followed by pyrrhotite, and progressively giving way to pyrite as the main iron sulfide, whereas Cu–Ag–Pb sulfosalts constitute late hypogene associations. Sphalerite is the chief ore mineral, and its crystallization is extended during most of the mineralization lifespan as evidenced by its initial cocrystallization with pyrrhotine, then with pyrite, and finally with Ag–Pb sulfosalts. The composition of sphalerite varies from early to late generations with a continuous decrease in FeS that attests to a decrease in temperature, which is constrained to vary from ~450 to <200 °C, and/or an increase in f(S2), both congruent with the described paragenetic sequence. Indium concentrated mostly in the structure of Fe-rich sphalerite (up to 3.49 wt. %) and stannite (up to 2.64 wt. %) as limited solid solutions with roquesite in the (Zn,Fe)S–Cu2FeSnS4–CuInS2 pseudoternary system. In sphalerite, In shows a strong positive correlation with Cu at Cu/In = 1, suggesting its incorporation via a (Cu+ + In3+) ↔ 2Zn2+ coupled substitution, and it does not correlate with Fe. In stannite, In shows a moderate, negative correlation with Cu and Sn, and an In3+ ↔ (Cu+ + ½ Sn4+) coupled substitution is suggested. Coexisting sphalerite and stannite yielded the highest In concentrations and crystallized at temperatures between 350 and 250 °C. Copper activity probably played a major role in the accumulation of In in the structure of sphalerite since In-bearing sphalerite coexisted with the deposition of stannite, shows high concentrations of Cu (up to 0.13 atoms per formula unit (a.p.f.u.)) in its structure, and hosts exsolutions of stannite and chalcopyrite. Distribution on the district scale of In suggests an input of hydrothermal fluids richer in Cu in the central position of the mineralizing system, represented by the Antón Bravo vein.

scholarly journals Coupled partitioning of Au and As into pyrite controls formation of giant Au deposits

2019 ◽  
Vol 5 (5) ◽  
pp. eaav5891 ◽  
Author(s):  
C. Kusebauch ◽  
S. A. Gleeson ◽  
M. Oelze
Keyword(s):  
Partition Coefficients ◽  
Hydrothermal Fluid ◽  
Iron Sulfide ◽  
Gold Deposits ◽  
Hydrothermal Systems ◽  
Hydrothermal Fluids ◽  
Balance Model ◽  
Mass Balance Model ◽  
Depositional Process ◽  
Partitioning Behavior

The giant Carlin-type Au deposits (Nevada, USA) contain gold hosted in arsenic-rich iron sulfide (pyrite), but the processes controlling the sequestration of Au in these hydrothermal systems are poorly understood. Here, we present an experimental study investigating the distribution of Au and As between hydrothermal fluid and pyrite under conditions similar to those found in Carlin-type Au deposits. We find that Au from the fluid strongly partitions into a newly formed pyrite depending on the As concentration and that the coupled partitioning behavior of these two trace elements is key for Au precipitation. On the basis of our experimentally derived partition coefficients, we developed a mass balance model that shows that simple partitioning (and the underlying process of adsorption) is the major depositional process in these systems. Our findings help to explain why pyrite in Carlin-type gold deposits can scavenge Au from hydrothermal fluids so efficiently to form giant deposits.

scholarly journals Challenging the thorium-immobility paradigm

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Haylea Nisbet ◽  
Artas A. Migdisov ◽  
Anthony E. Williams-Jones ◽  
Hongwu Xu ◽  
Vincent J. van Hinsberg ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Low Temperature ◽  
Nuclear Fuel ◽  
Fuel Cycle ◽  
Nuclear Fuel Cycle ◽  
Hydrothermal Fluids ◽  
Solubility Data ◽  
Aqueous Systems ◽  
Hydrothermal Deposits ◽  
High Concentrations

AbstractThorium is the most abundant actinide in the Earth’s crust and has universally been considered one of the most immobile elements in natural aqueous systems. This view, however, is based almost exclusively on solubility data obtained at low temperature and their theoretical extrapolation to elevated temperature. The occurrence of hydrothermal deposits with high concentrations of Th challenges the Th immobility paradigm and strongly suggests that Th may be mobilized by some aqueous fluids. Here, we demonstrate experimentally that Th, indeed, is highly mobile at temperatures between 175 and 250 °C in sulfate-bearing aqueous fluids due to the formation of the highly stable Th(SO4)2 aqueous complex. The results of this study indicate that current models grossly underestimate the mobility of Th in hydrothermal fluids, and thus the behavior of Th in ore-forming systems and the nuclear fuel cycle needs to be re-evaluated.

scholarly journals Leaching of Fluoride from Biotite Mica in Soil: Implications for Fluoride in Shallow Groundwater

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
K. U. K. S. Kularatne ◽  
H. M. T. G. A. Pitawala
Keyword(s):  
Citric Acid ◽  
Complex Formation ◽  
Organic Acids ◽  
Shallow Groundwater ◽  
Ionic Exchange ◽  
Strong Positive Correlation ◽  
High Concentration ◽  
Short Term ◽  
Inorganic Acids ◽  
High Concentrations

Leaching of from biotite was investigated at room temperature by performing a series of short-term leach tests. The leaching of from biotite structure strongly depends on its weathering stage. Results of this study suggest that high concentration of is leached from highly weathered biotite, compared to fresh biotite. Results of dissolution experiments confirm that the organic acids in soil promote the leaching of from biotite compared to inorganic acids. Citric acid which is a week organic acid enhances leaching of from biotite structure compared to strong inorganic acid HNO3, independent of the weathering stage of biotite. Strong positive correlation between K+ and Fe2+ with in biotite treated with citric acid suggests that readily leachs into the solution through an ionic exchange and complex formation. Organic acids involve sorption and complex formation processes leading to release of into the solution. Our studies suggest that in the presence of organic acids is leached readily into water percolating through the soil. Therefore, shallow groundwater replenished by the water table may achieve high concentrations by this leaching process.

Analysis of Bacterial Kill Versus Corrosion From Use of Common Oilfield Biocides

2010 ◽  
Author(s):  
Vic Keasler ◽  
Brian Bennett ◽  
Heather McGinley
Keyword(s):  
Iron Sulfide ◽  
Heterotrophic Bacteria ◽  
Negative Impact ◽  
High Water ◽  
Microbiologically Influenced Corrosion ◽  
General Corrosion ◽  
Severe Problem ◽  
Sulfate Reducing ◽  
Corrosion Rates ◽  
High Concentrations

Bacterial proliferation is a severe problem in many oilfield systems, especially in aging systems with high water cuts. Depending on the types of microorganisms present, they can cause microbiologically influenced corrosion (MIC) or biofouling of filters, membranes, and metal surfaces. Common oilfield bacteria include sulfate-reducing bacteria (SRB) that can generate hydrogen sulfide (H2S) and iron sulfide (FeS) as a by-product (iron sulfide can occur in different structural forms), acid producing bacteria that can secrete organic acids that lower the pH within the microenvironment of a biofilm, as well as general heterotrophic bacteria that are often important in biofilm formation and maintenance, amongst others. To prevent corrosion or biofouling caused by these organisms, biocides are commonly added to the production fluids. Some concern has arisen that common oilfield biocides may be inherently corrosive at high end use concentrations and could cause general corrosion in the assets they are protecting from MIC. Accordingly, it is important to understand the risk of MIC, souring, and biofouling versus general corrosion from the biocides themselves. To examine the killing efficiency of oilfield biocides versus their corrosive potential, laboratory work was undertaken with five biocide products including: Tetrakis (hydroxymethyl) phosphonium sulfate (THPS), glutaraldehyde, glutaraldehyde / alkyldimethylbenzyl ammonium chloride (ADBAC) mixture, 5-chloro-2-methyl-4-isothiazolin-3-one/2-methyl-4-isothiazolin-3-one (CMIT/MIT), and a cocodiamine (quaternary amine). Each biocide was evaluated at four different concentrations ranging from 10–100,000 ppm of product. Killing efficiency was determined via bacterial kill studies, while wheelbox and bubble cell testing examined corrosion rates. Corrosion rates varied quite substantially from one biocide to the next, especially at high concentrations. Some biocides were found to be only mildly corrosive even at high dosages, while other biocides were much more corrosive at high concentrations. In general, it was observed that biocide corrosivity is directly related to the dosage of the biocide, with higher dosages correlating with higher corrosion rates. On the other hand, biocides were shown to be effective at killing common oilfield bacteria at relatively low dosages. This data suggests that biocides can be effective at killing bacteria at concentrations that do not cause significant amounts of general corrosion. Additionally, the common practice of batch treating biocides minimizes contact time between the biocide and the metal surface, which is in turn expected to minimize any corrosion that would otherwise be attributed to the biocides themselves. Taken together, this data would suggest that the benefit of biocide treatment to prevent MIC and biofouling substantially outweighs any potentially negative impact on corrosion.

scholarly journals Tracking the temporal variation of COVID-19 surges through wastewater-based epidemiology during the peak of the pandemic: a six-month long study in Charlotte, North Carolina

2021 ◽  
Author(s):  
Visva Bharati Barua ◽  
Md Ariful Islam Juel ◽  
A. Denene Blackwood ◽  
Thomas Clerkin ◽  
Mark Ciesielski ◽  
...  
Keyword(s):  
North Carolina ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Strong Positive Correlation ◽  
Municipal Wastewater Treatment ◽  
Fecal Shedding ◽  
Global Pandemic ◽  
High Concentrations ◽  
Municipal Wastewater Treatment Plants ◽  
Influent Wastewater

The global spread of SARS-CoV-2 has continued to be a serious concern after WHO declared the virus the causative agent of the coronavirus disease 2019 (COVID-19) a global pandemic. Monitoring of wastewater is a useful tool for assessing community prevalence given that fecal shedding of SARS-CoV-2 occurs in high concentrations by infected individuals, regardless of whether they are asymptomatic or symptomatic. Using tools that are part of the wastewater-based epidemiology (WBE) approach, combined with molecular analyses, wastewater monitoring becomes a key piece of information used to assess trends and quantify the scale and dynamics of COVID-19 infection in a specific community, municipality, or area of service. This study investigates a six-month long SARS-CoV-2 RNA quantification in influent wastewater from four municipal wastewater treatment plants (WWTP) serving the Charlotte region of North Carolina (NC) using both RT-qPCR and RT-ddPCR platforms. Influent wastewater was analyzed for the nucleocapsid (N) genes N1 and N2. Both RT-qPCR and RT-ddPCR performed well for detection and quantification of SARS-CoV-2 using the N1 target, while for the N2 target RT-ddPCR was more sensitive. SARS-CoV-2 concentration ranged from 103 to105 copies/L for all four plants. Both RT-qPCR and RT-ddPCR showed a significant moderate to a strong positive correlation between SARS-CoV-2 concentrations and the 7-day rolling average of clinically reported COVID-19 cases using a lag that ranged from 7 to 12 days. A major finding of this study is that despite small differences, both RT-qPCR and RT-ddPCR performed well for tracking the SARS-CoV-2 virus across WWTP of a range of sizes and metropolitan service functions.

scholarly journals Intramammary antibiotics in dairy goats : effect of stage of lactation, parity and milk volume on withdrawal periods, and the effect of treatment on milk compositional quality

2007 ◽  
Vol 74 (3) ◽  
Author(s):  
J. Karzis ◽  
E.F. Donkin ◽  
I.M. Petzer
Keyword(s):  
Negative Correlation ◽  
Milk Fat ◽  
Animal Health ◽  
Cow Milk ◽  
Strong Positive Correlation ◽  
Withdrawal Period ◽  
Dairy Goats ◽  
Positive Correlation ◽  
Stage Of Lactation ◽  
Moderate Negative Correlation

The length of the antibiotic withdrawal period after intramammary treatment was influenced by the milk yield of dairy goats during this trial. Shorter withdrawal periods were seen in relatively high yielding dairy goats (production above 1.5 ℓ per day) compared to low producers (less than 1.3 ℓ per day). High yielding goats treated with Curaclox LC (Norbrook [Pharmacia AH]) had a withdrawal period of 42 h, while low yielding goats, treated with the same product, had a withdrawal period of 74 h. The recommended withdrawal period for Curaclox LC for use in cattle is 72 h. Relatively high yielding goats treated with Rilexine 200 LC (Logos Agvet [Virbac]) had a significantly shorter withdrawal period (37 h) than that recommended for use in cattle (96 h). Low yielding goats treated with Spectrazol Milking Cow (Schering-Plough Animal Health) had a significantly longer (95 h) withdrawal period than that recommended for use in cattle (60 h). Withdrawal periods were also influenced by stage of lactation and parity. There was a moderate positive correlation between lactation number and withdrawal period, as measured by TRIS (R2 = 0.621), and a moderate negative correlation between stage of lactation and withdrawal period (R2 = -0.669). In Trials 1, 2 and 3 combined there was a moderate negative correlation between withdrawal period and volume (R2 = -0.511) and a strong positive correlation between withdrawal period and lactation number (R2 = 0.720). The differences in percentage milk fat, protein and lactose before, during and after treatment were not statistically significant except in Trial 3 (Curaclox LC and Rilexine 200 LC) where protein and lactose differed significantly. In Trial 2 (Spectrazol Milking Cow) milk fat percentages differed significantly between treatment and control groups as did protein percentages in Trial 3. These differences are however, not biologically meaningful.

Evolution of Multistage Hydrothermal Fluids in the Luoboling Porphyry Cu-Mo Deposit, Zijinshan Ore Field, Fujian Province, China: Insights from LA-ICP-MS Analyses of Fluid Inclusions

2020 ◽  
Author(s):  
Xiao-Yu Zhao ◽  
Hong Zhong ◽  
Rui-Zhong Hu ◽  
Wei Mao ◽  
Zhong-Jie Bai ◽  
...  
Keyword(s):  
Fluid Inclusions ◽  
Hydrothermal Systems ◽  
Hydrothermal Fluids ◽  
Common Source ◽  
Two Phase ◽  
Porphyry Cu ◽  
Icp Ms ◽  
High Concentrations ◽  
Granodiorite Porphyry ◽  
Increasing Trends

Abstract The Luoboling Cu-Mo deposit, with 1.4 million tons (Mt) Cu and 0.11 Mt Mo, is the largest porphyry deposit in the Zijinshan district of southeast China. Mineralization at Luoboling is divided into premineralization, synmineralization, and late-mineralization stages. Consistent Cs/(Na + K) ratios in fluid inclusions suggest that the mineralizing fluids originated from a common source—the Luoboling granodiorite porphyry. The absence of initial supercritical fluid inclusions and abundant coexisting vapor and brine fluid inclusions imply that the fluids exsolved at low-pressure two-phase conditions, with temperatures of 250° to 600°C and salinities of 30 to 60 wt % NaCl equiv (brines) and &lt;10 wt % NaCl equiv (vapors). The deposit formed at ~120 to 800 bar, corresponding to the depths of ~1.2 to 3.2 km (assuming a transition from lithostatic to hydrostatic load). Metals such as Mo (up to 77 ppm), Pb (up to 8,800 ppm), Zn (up to 13,000 ppm), and Ag (up to 130 ppm) migrated mainly in brines. Although vapor inclusions have high concentrations of Cu (up to 20,000 ppm), hypersaline fluid was the major medium for Cu transport and precipitation. The successive precipitation of Mo and Cu occurred when fluids cooled to ~500°C and ~350° to 450°C, respectively. The late-stage quartz-pyrite veins with phyllic alteration were formed by Cu-rich magmatic hydrothermal fluids. The Zijinshan epithermal Cu-Au deposit and the Luoboling porphyry Cu-Mo deposit originated from independent hydrothermal systems. Nonetheless, the increasing trends of Pb, Zn, and Ag concentrations in different stage inclusions from Luoboling imply potential for distal Pb-Zn-Ag mineralization.

scholarly journals The correlation between spinal and chest wall deformities and pulmonary function in Marfan syndrome

2020 ◽  
Vol 14 (4) ◽  
pp. 343-348
Author(s):  
Hila Otremski ◽  
Roger F. Widmann ◽  
Mary F. Di Maio ◽  
Dror Ovadia
Keyword(s):  
Pulmonary Function ◽  
Chest Wall ◽  
Marfan Syndrome ◽  
Negative Correlation ◽  
Spinal Deformity ◽  
Strong Positive Correlation ◽  
Chest Wall Deformity ◽  
Moderate Negative Correlation ◽  
The Impact ◽  
The Relationship

Purpose Scoliosis, chest wall deformities and pulmonary involvement are common features of Marfan syndrome (MFS). We aimed to assess the impact of spinal and chest wall deformities on pulmonary function in paediatric MFS patients with a surgically managed spinal deformity. Methods In this multicentre retrospective study, spirometry, lung volumes and radiographic imaging were performed on 26 MFS patients between the ages of seven and 18 years who were undergoing planned spinal fusion surgery for spinal deformity. A correlation analysis assessed the relationship between radiographic measurements of spinal and chest wall deformities and predicted total lung capacity (TLC), forced vital capacity (FVC) and the ratio between forced expiratory volume in one second and FVC (FEV1/FVC). Results In total, 18 patients (70%) had impaired pulmonary function. Thoracic kyphosis (mean 19.3°; -32° to 54°) had a strong positive correlation with FEV1/FVC (r = 0.65; p < 0.001). Significant decrease in FEV1/FVC below 80% occurred at kyphosis under 15° (p = 0.004). Kyphosis had a moderate negative correlation with FVC (r = -0.43; p = 0.03). Chest wall deformity had a strong negative correlation with FEV1/FVC (r = -0.61; p = 0.001). The magnitude of the thoracic curve (mean 55.2°; 28° to 92°) had a significant moderate negative correlation with TLC (r = -0.45; p = 0.04). Conclusion In MFS, three factors correlate with decreased pulmonary function measures: hypokyphosis, increasing chest wall deformity and increasing coronal curve magnitude. Hypokyphosis and increased chest wall deformity correlated with diminished FEV1/FVC; increasing thoracic spinal curvature with diminished TLC. Further analysis with a larger cohort will help better define the relationship between these deformities and pulmonary function in this unique population. Level of Evidence IV

scholarly journals Determination of Spearman Correlation Coefficient(r)to Evaluate the Linear Association of Dermal Collagen and Elastic Fibers in the Perspectives of Skin Injury

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Naveen Kumar ◽  
Pramod Kumar ◽  
Satheesha Nayak Badagabettu ◽  
Melissa Glenda Lewis ◽  
Murali Adiga ◽  
...  
Keyword(s):  
Correlation Coefficients ◽  
Scar Formation ◽  
Elastic Fibers ◽  
Strong Positive Correlation ◽  
Spearman Correlation ◽  
Unequal Distribution ◽  
Positive Correlation ◽  
Dermal Collagen ◽  
Human Cadavers ◽  
Moderate Negative Correlation

Background. Difference in scar formation at different sites, in different directions at the same site, but with changes in the elasticity of skin with age, sex, and race or in some pathological conditions, is well known to clinicians. The inappropriate collagen syntheses and delayed or lack of epithelialization are known to induce scar formation with negligible elasticity at the site of damage. Changes in the elasticity of scars may be due to an unequal distribution of dermal collagen (C) and elastic (E) fibers.Materials and Methods. Spearman correlation coefficients (r) of collagen and elastic fibers in horizontal (H) and in vertical (V) directions (variables CV, CH, EV, and EH) were measured from the respective quantitative fraction data in 320 skin samples from 32 human cadavers collected at five selected sites over extremities.Results. Spearman’s correlation analysis revealed the statistically significant (p<0.01) strong positive correlation betweenCHandCVin all the areas, that is, shoulder joint area (r=0.66), wrist (r=0.75), forearm (r=0.75), and thigh (r=0.80), except at the ankle (r=0.26,p=0.14) region. Similarly, positive correlation betweenEHandEVhas been observed at the forearm (r=0.65, moderate) and thigh (r=0.42, low) regions. However, a significant moderate negative correlation was observed betweenCVandEVat the forearm (r=-0.51) and betweenCHandEHat the thigh region (r=-0.65).Conclusion. Significant differences of correlations of collagen and elastic fibers in different directions from different areas of extremities were noted. This may be one of the possible anatomical reasons of scar behavior in different areas and different directions of the same area.

scholarly journals Resting Heart Rate and Auditory Evoked Potential

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Simone Fiuza Regaçone ◽  
Daiane Damaris Baptista de Lima ◽  
Vitor Engrácia Valenti ◽  
Ana Cláudia Figueiredo Frizzo
Keyword(s):  
Heart Rate ◽  
Evoked Potential ◽  
Rest Heart Rate ◽  
Auditory Evoked Potential ◽  
Strong Positive Correlation ◽  
Resting Heart Rate ◽  
Heart Rate Monitor ◽  
Healthy Female ◽  
Related Potentials ◽  
Moderate Negative Correlation

The objective of this study was to evaluate the association between rest heart rate (HR) and the components of the auditory evoked-related potentials (ERPs) at rest in women. We investigated 21 healthy female university students between 18 and 24 years old. We performed complete audiological evaluation and measurement of heart rate for 10 minutes at rest (heart rate monitor Polar RS800CX) and performed ERPs analysis (discrepancy in frequency and duration). There was a moderate negative correlation of the N1 and P3a with rest HR and a strong positive correlation of the P2 and N2 components with rest HR. Larger components of the ERP are associated with higher rest HR.

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