Tail Volume Research Articles

Towards mine tailings valorization: Recovery of critical materials from Chilean mine tailings

The mining industry produces large volumes of mine tailings – a mix of crushed rocks and process effluents from the processing of mineral ores. Mine tailings are a major environmental issue due to implications related to their handling and storage. Depending on the mined ore and the process used, it may be possible to recover valuable elements from mine tailings, among them critical raw materials (CRMs) like rare earths, vanadium, and antimony.The aim of this study was to investigate the techno-economic feasibility of producing critical raw materials from mine tailings. Data from 477 Chilean tailings facilities were analyzed and used in the techno-economic assessment of the valorization of mine tailings in the form of CRMs recovery. A review of applicable technologies was performed to identify suitable technologies for mine tailings processing. To assess the economic feasibility of CRMs production, net present value (NPV) was calculated using the discounted cash flow (DCF) method. Sensitivity analysis and design of experiments were performed to analyze the influence of independent variables on NPV. Two options were assessed, rare earth oxides (REOs) production and vanadium pentoxide (V2O5) production. The results show that it is possible to produce V2O5 with an NPV of 76 million US$. In the case of REOs, NPV is positive but rather low, which indicates that the investment is risky. Sensitivity analysis and the ANOVA run using the design of experiments indicated that the NPV of REOs is highly sensitive to the price of REOs and to the discount rate.

Abstract 182: Orally Administered 9-cis Retinoid Acid Improves Functional Lymphatic Drainage In Post-surgical Lymphedema

Purpose: We have previously shown that daily intraperitoneal administration of 9-cis Retinoic Acid (9-cis RA) is associated with increased lymphangiogenesis and lymphatic clearance in a mouse tail model of lymphedema. Since an oral dosing regimen would have higher clinical translatability, we sought to determine if orally administered 9-cis RA was similarly effective in preventing lymphedema. Methods: In a mouse tail model, secondary lymphedema was induced by excising 5 mm of skin circumferentially and obliterating all remaining lymphatics utilizing injection of methylene blue and the operative microscope. Twenty-five sex-matched FVB mice aged weighing between 20 and 30 grams were assigned to one of three groups: control (n=8), low-dose 9-cis RA (n=8), and high-dose 9-cis RA (n=9). 9-cis retinoic acid was dissolved in soybean oil, and vehicle control consisted of soybean oil. Low-dose 9-cis RA mice and high-dose 9-cis RA mice received doses of 10 mg/kg and 30 mg/kg respectively, and each mouse was given 0.15 mL of solution via oral gavage daily. The tail images were taken every week for 6 weeks and analyzed with ImageJ software. On POD42, mice tails were injected intradermally with indocyanine green (ICG), and fluorescence was captured and quantified via NOVADAQ Spy Fluorescence Imaging at 0, 1, 3, 6, 12, 24, 48, 72, and 96 hours. Lastly, a comprehensive metabolic panel was performed on the blood serum of each mouse. Results: The percentage change in tail volume of the low 9-cis RA group was statistically lower than the control group at all time points beginning on POD14 (p < 0.05). At POD14, the mean change in tail volume for the low 9-cis RA group and control groups were 18.11% and 69.26% respectively (p < 0.001). The percentage change in fluorescence from hour 1 post-ICG injection was significantly different between low-dose 9-cis RA group and the control group at 72, 96, and 120 hours (p < 0.05). The high-dose 9-cis RA group did not show a significant difference in tail volume change or fluorescence change relative to the control group. In addition, the high-dose 9-cis RA group demonstrated mild cutaneous irritation in the perioral and throat regions while these adverse events were not observed in the low-dose 9-cis RA group. The chemistry panel results showed no significant differences between control and both 9-cis RA groups, and there was no significant difference in weights for any groups at any time point. Conclusion: Treatment with orally administered 9-cis RA at an oral dose of 10 mg/kg attenuates the volume change associated with lymphedema and improves lymphatic drainage in a mouse tail model. These findings offer a potential preventative treatment for patients at risk of developing secondary lymphedema.

Сomprehensive evaluation of strategy for mining of iron ore deposits by environmentally-balanced underground geotechnology

For the purpose to solve the problem of reducing the negative impact of mining and processing production on the environment that is relevant for most mining regions of Russia, options of geotechnological strategy for mining of iron ore deposits on the basis of an ecologically balanced integrated underground geotechnology of extraction and processing of iron ore, which allow to utilize the entire volume of mining and processing waste in the mined out space and transfer the most environmentally hazardous enrichment process under the ground, have been formed. Technological schemes for chamber excavation of floors in ascending order have been developed, which make it possible to abandon the formation of ore pillars, thereby increasing the extraction of ore from the bowels, and using the worked out space for waste storage in the form of a dry backfill. Based on economic and mathematical modeling and a comprehensive assessment according to the environmental and economic criterion for the conditions of mining in a new step of one of the largest iron ore deposits in Russia the most effective option of geotechnical strategy has been established. Use of an ascending-descending order of floor mining with an optimal ratio of mining systems with laying out the worked out space and systems with collapse depending on the content of the useful component in the ore mined, the amount of space mined current tab and the volume of tailings used as backfill material, allows to utilize the entire volume of mining and processing waste in the mined out space and effectively to develop of reserves in a new step.

Utilização dos rejeitos de minério de ferro na construção civil: uma análise cienciométrica

A demanda do mercado internacional por minério de ferro gera um crescimento nas indústrias mineradoras, aumentando o volume de rejeitos gerados, que são depositados em barragens de contenção cada vez maiores. Entretanto, diversos acidentes ocorridos mundialmente com barragens indicam a necessidade de um plano de gestão dos rejeitos provenientes da mineração. Assim, este trabalho objetivou a avaliação da evolução espaço-temporal de artigos associados ao uso de rejeitos de mineração de ferro na construção civil. Para tal, foi realizada uma pesquisa documental, de abordagem quali-quantitativa, através da ciênciometria, que resultou em uma amostra de 98 artigos publicados entre os anos de 1960 e 2018. Os dados obtidos indicam um crescimento exponencial de trabalhos científicos publicados, sendo que os países com maior número de artigos referentes ao tema estudado foram China (41%), Índia (11%) e Brasil (9%). As áreas de conhecimento com maior número de publicações foram a Engenharia com (28,1%), Ciências dos Materiais (24,1%) e Tecnologia de Construção (15,3%). Os materiais que mais comumente utilizaram rejeito em sua composição foram o concreto, citado em 34 artigos e cimento, citado em 11 publicações. As técnicas de análises mais citadas nos artigos foram os testes mecânicos, químicos, físicos e morfológicos. Ressalta-se que o reaproveitamento de rejeitos provenientes da mineração na construção civil reduz impactos ambientais negativos associados à disposição desses materiais, além de contribuir para a redução da demanda por recursos naturais.

Microbially-mediated de-watering and consolidation (“Biodensification”) of oil sands mature fine tailings, amended with agri-business by-products

Oil sands surface mining operations in northeastern, Alberta, Canada produce enormous volumes of fluid fine tailings, an aqueous suspension of fine clays, sand, unrecovered bitumen, and diluent hydrocarbons. The tailings are deposited and retained on-site in large settling basins where the colloidal solids sediment and consolidate very slowly by gravity and pore water collects at the surface for re-use. Tailings ‘biodensification’, mediated by indigenous microbes that produce methane and/or carbon dioxide, is a phenomenon observed in situ and in vitro whereby tailings with active anaerobic microbial communities consolidate and de-water faster than predicted by gravitational (self-weighted) consolidation alone. To exploit this phenomenon, we used organic amendments to stimulate endogenous anaerobic tailings microorganisms. Tailings from three different operators were amended with agri-business by-products, placed in 100-mL microcosms and 1.5-L settling columns, and monitored for methanogenesis, pore water recovery, and solids densification. Several amendments increased methane production and accelerated biodensification compared to unamended and negative controls. Hydrolyzed canola, blood meal, bone meal and glycerol generally accelerated biodensification, stimulated methane production and supported growth of methanogens and fermentative microbes. Amendment altered the chemistry of the tailings, generally decreasing pH, increasing conductivity and magnesium, potassium, sodium, and bicarbonate concentrations. Biodensification is a potential engineered technology for accelerating water recovery and reducing the volume of stored oil sands tailings.

The dissolution characteristic of nonionic surfactants in supercritical CO2

The effects of surfactant structures on the supercritical carbon dioxide (scCO2) solubility are investigated to shed some light on the application of scCO2 in chemical procedures. The dissolution pressure of three nonionic surfactants (TX45, TX100 and OP-10) in scCO2 was measured. Solubility results reveal that surfactant with branched alkyl chains shows better solubility than surfactant with linear alkyl chains. This may be due to the volumes occupied by the hydrophobic tails of these nonionic surfactants. TX45 with the largest tail volume and lowest molecular weight performs the largest solubility in scCO2. In addition, the solubility results of three nonionic surfactants in scCO2 at the temperature range of 305 K to 325 K show that solubility is proportional to the pressure and density of scCO2, and inversely proportional to the experimental temperature. Finally, two density-based models (Chrastil model and Bartle model) are applied to correlate the experimental solubility data, and the results show good agreements for the experimental data of investigated nonionic surfactants. Similar agreements with experimental solubility data of surfactants are obtained by both models and the average absolute relative deviation (AARD) values lower than 2% were obtained.

Linking hydrocarbon biodegradation to greenhouse gas emissions from oil sands tailings and its impact on tailings management

Microbial research for maintaining soil productivity, health, and environment as well as for ecosystem function has been one of the main research focuses in the Department of Renewable Resources (formerly Department of Soil Science) during the last 100 yr. In recent years, microbial research has been expanded to effectively reclaim disturbed land, remediate contaminated sites, and manage soft sediments such as huge volumes of oil sands tailings. This article highlights the microbial processes in tailings ponds that can affect strategies to manage growing inventory of oil sands tailings and reduce associated environmental footprint. Enormous volumes of fluid fine tailings produced during bitumen extraction from oil sands are retained in tailings ponds. Some tailings streams contain residual labile hydrocarbons originated from the hydrocarbon solvents used in the extraction process. Indigenous microorganisms acclimated to the pond environment metabolize certain fractions of the fugitive labile hydrocarbons into biogenic greenhouse gases (GHG) such as methane (CH4) and carbon dioxide (CO2). Long-term (1–7 yr) biodegradation studies conducted using mature fine tailings (MFT) collected from different tailings ponds reveal that the microorganisms sequentially and preferentially biodegrade hydrocarbons under methanogenic conditions. The stoichiometric mathematical model developed on these biodegradation studies can predict GHG emissions from tailings ponds. Production of biogenic gases also affects the porewater and solid-phase chemistry of MFT and accelerates their de-watering and consolidation during active methanogenesis, which is beneficial for recovery of porewater for reuse in the bitumen extraction process and for effective reclamation of consolidated material.

Characterization and processing of plant tailings for the recovery of fine garnet - a case study

ABSTRACT Processing of tailings from a garnet operation was investigated to recover lost garnet. Analyses showed the tailings contained ~15% recoverable garnet. Because current processing utilizes spiral concentrators, different gravity separations were investigated but also included magnetic separation either in the absence or presence of comminution. Combinations of Crossflow separation, tabling and magnetic separation failed with no additional comminution. However, after the tailings were sized and the +1.18 mm fraction was crushed and mixed with the −1.18 mm fraction, a garnet concentrate was obtained at ~15% mass yield with ~80% purity. Results suggest this process will improve economic performance and reduce tailings volume.

Degradation of surfactant used in iron mining by oxidation technique: Fenton, photo‐Fenton, and H2O2/UV—A comparative study

AbstractReuse of water in mining helps reduce the volume of tailings directed to dams, avoiding overloads and ruptures, as occurred in Brumadinho, Brazil. Water reuse in mining requires treatment mainly for removing the surfactant substances used. Photo‐Fenton and UV/H2O2 showed 96% to 98% degradation results of anionic surfactants within 5 minutes, suggesting this technique is faster than biological systems that can take days. This paper aims to study the degradation of a surfactant used in the flotation process by UV/H2O2, Fenton, and photo‐Fenton oxidation techniques. The compound was characterized by FTIR and MALDI‐TOF. In degradation experiments, the variation in reactants concentrations was evaluated with hydrogen peroxide, iron sulphate heptahydrate, and oxalic acid. We used a synthetic solution of surfactant in the reverse flotation of ore with 180 mg/L. The reaction was monitored with TOC analysis and a spectrophotometer throughout the reaction. The UV/H2O2 and Fenton system were studied by varying peroxide and iron concentrations, with 120 minute tests. Additionally, photo‐Fenton concentrations, the pH variation (1.5‐8.0), temperature (15°C, 21°C, and 60°C), and time were evaluated. The results showed the most efficient degradation was that using photo‐Fenton, which achieved total TOC removal using 4500 mg/L of peroxide and 364 mg/L of iron for 330 minutes, while the UV/H2O2 system achieved 29% and 49% TOC removal of the Fenton. It is verified that the oxidative processes can be applied to degrade the surfactants present in the water recovered from the flotation processes.

LA ACTIVIDAD MINERA DEL SIGLO XX EN EL VALLE DE OAXACA: RIESGOS DE SALUD PÚBLICA DE HOY

The abandonment of mining is a topic that has gone unnoticed in the national debate since the mid-twentieth century, as well as in the normativity. The tailings, stacks of ground rocks that remain after the minerals of interest are extracted from the rocks, have a socio-environmental impact. However, the responsibilities of companies, the State and, in general, of civil society against the contaminating effects of tailings have not been defined. The present study evaluates the socio-environmental situation in San Jeronimo Taviche, Oaxaca, Mexico, where transnational companies generated large volumes of tailings. To evaluate the environmental part, 10 samples of water bodies and 13 soil samples were analyzed in which the concentration level of the total heavy metals (cadmium, copper, mercury, lead and zinc) was quantified by atomic absorption spectrophotometry. To evaluate the social aspects, semi-structured interviews were conducted with the miners, telesecundaria students and doctors from the health center, where the working conditions, the extraction processes of the heavy metals and the most common diseases in the miners were registered. It was found that the concentrations of some metals exceed the limits established by current Mexican normativity; in addition, interviews showed that the population is unaware of the health risks arising from the tailings. The present investigation allows understanding the vision of the sanitary and environmental risks that the abandoned tailings represent for the population.

Salamander stress and duress: the relationship between CORT, autotomy and regeneration, and exploratory behaviour

Responses to stress are generally mediated through the production of glucocorticoids by the hypothalamic-pituitary-adrenal (or -interrenal) axis. The prolonged production of stress hormones can contribute to delayed wound healing and growth, but little is known about their influence on regeneration following tail autotomy, or exploratory behaviour in autotomized individuals. Here we examined the relationship between stress, regeneration, and exploratory behaviour in Allegheny Mountain dusky salamanders (Desmognathus ochrophaeus) by manipulating corticosterone (CORT) levels via cutaneous patch. First, we measured tail regeneration in salamanders with elevated CORT for 13 weeks after the induction of tail autotomy. Test subjects received a weekly patch to wear for one hour that was saturated with either a low CORT (0.25 mg/ml) or high CORT (0.50 mg/ml) solution. Individuals receiving CORT patches regenerated significantly less of their tail length and volume (versus control), but without exhibiting dose-dependent effects. Second, we used a factorial design to evaluate the effects of autotomy and elevated CORT on exploration within a test arena consisting of low barriers arrayed in concentric rings. Individuals experiencing tail autotomy exhibited significantly less exploratory behaviour indicated by an increased latency to cross first barrier and a decreased number of barriers crossed. Neither elevated CORT (0.50 mg/ml), nor the interaction between elevated CORT and tail autotomy significantly affected salamander activity within the array. Although CORT did not have a direct effect on explorative behaviour, a delay in regeneration attributed to CORT could lead to changes in patterns of movement in autotomized individuals.

Growth and physiological responses of tree seedlings to oil sands non-segregated tailings

Bitumen recovery from oil sands in northeastern Alberta, Canada produces large volumes of tailings, which are deposited in mining areas that must be reclaimed upon mine closure. A new technology of non-segregated tailings (NST) developed by Canadian Natural Resources Limited (CNRL) was designed to accelerate the process of oil sands fine tailings consolidation. However, effects of these novel tailings on plants used for the reclamation of oil sands mining areas remain to be determined. In the present study, we investigated the effects of NST on seedlings of three species of plants commonly planted in oil sands reclamation sites including paper birch (Betula papyrifera), white spruce (Picea glauca) and green alder (Alnus viridis). In the controlled-environment study, we grew seedlings directly in NST and in the two types of reclamation soils with and without added NST and we measured seedling growth, gas exchange parameters, as well as tissue concentrations of selected elements and foliar chlorophyll. White spruce seedlings suffered from severe mortality when grown directly in NST and their needles contained high concentrations of Na. The growth and physiological processes were also inhibited by NST in green alder and paper birch. However, the addition of top soil and peat mineral soil mix to NST significantly improved the growth of plants, possibly due to a more balanced nutrient uptake. It appears that NST may offer some advantages in terms of site revegetation compared with the traditional oil sands tailings that were used in the past. The results also suggest that, white spruce may be less suitable for planting at reclamation sites containing NST compared with the two studied deciduous tree species.

Duodenal-preserving pancreatic head resection with limited distal pancreatectomy: A novel, tailored approach for chronic pancreatitis

Presenter: Thomas Maatman MD | Indiana University Background: Operative management of chronic pancreatitis (CP) must be tailored to individual patient’s anatomy to achieve durable symptom relief. Incomplete drainage of an atrophic pancreatic tail is a common cause of symptom recurrence in patients undergoing drainage procedures. We have selectively applied limited distal pancreatectomy (DP) with duodenal-preserving pancreatic head resection (DPPHR) to patients with appropriate anatomy and hypothesized that this novel procedure provides durable therapy. Methods: Ten patients underwent DPPHR combined with limited DP between 2013-2018. Patient demographics, comorbidities, perioperative outcomes, and long-term CP-specific outcomes were recorded. Measurements of the pathology specimen determined pancreas tail volume. Chronic pancreatitis specific outcomes included endocrine/exocrine insufficiency, pain relief, and nutritional status. The amount of opioid pain medication was reported as daily morphine equivalents. Body mass index (BMI) and albumin were reported as surrogates for nutritional status. Descriptive statistics were applied. Continuous data are reported as means ± standard error of the mean. Results: Ten patients (8 females; age 49 ± 3 years) had etiology of idiopathic (n = 4), alcohol (n = 2), sequelae of severe acute pancreatitis (n = 1), hereditary (n = 1), autoimmune (n = 1), and pancreas divisum (n = 1). Operation was 57 ± 14 months after CP diagnosis. Patients had 6 ± 1 endoscopic procedures prior to operation. Mean operative time was 215 ± 11 minutes; estimated blood loss was 110 ± 28 mL. On average, 6 ± 1 cm of pancreatic tail was resected. Splenic preservation was possible in 7 patients. Postoperative LOS was 13 ± 2 days. Postoperative morbidity occurred in two patients; one grade B postoperative pancreatic fistula and one perforated duodenal ulcer. Readmission occurred in 5/10 patients at median time of 36 days (range, 16-78 days) postoperatively. Causes included abdominal pain (n = 2), small bowel obstruction (n = 1), intraabdominal abscess requiring antibiotic therapy (n = 1), and failure to thrive (n = 1). No perioperative mortality occurred. Overall, analgesic requirements and nutrition (measured by albumin) improved substantially (Figure 1). In addition, improvement in BMI (preoperative, 23.5 ± 1 kg/m2) was sustained at one- (23.7 ± 1 kg/m2), three- (25.6 ± 1 kg/m2), and five-years postoperatively (24.2 ± 1 kg/m2). At operation, 20% of patients required insulin; at five-year follow up this number was 25%. Eighty percent of patients were prescribed exocrine replacement preoperatively; all patients were on exocrine replacement at five-year follow up. During follow up (mean, 38 ± 7 months), one patient with hereditary CP underwent salvage total pancreatectomy with islet cell auto-transplantation 13 months postoperatively. Conclusion: In select chronic pancreatitis patients, including limited distal pancreatectomy with duodenal-preserving pancreatic head resection provides durable, long-term pain relief and improves nutritional parameters with minimal effect on pancreatic endocrine and exocrine function. This operation should be considered in select patients with appropriate anatomy.

Experimental research on biochemical consolidation of bauxite tailings clay

Microbially induced carbonate precipitation (MICP) is rarely applied to clay. With the aim of tailings reservoir reclamation, measurements for compression tests, scanning electron microscope (SEM) observations and mercury intrusion porosimetry (MIP) tests were conducted to study the macroscopic strength and microstructure of the over-wet bauxite tailings clay with different water contents (w) after biochemical consolidation and quicklime solidification. These tests indicate that the compressibility (av1-2) of tailings clay with w = 60% after biochemical consolidation is less than that obtained with w = 80% and can reach the index of low compressibility. In addition, the cumulative pore volume is also less than that with w = 80%, but the volume percentage of small pores for tailings clay with w = 60% is larger than that with w = 80%. As the quicklime content increases, the compressibility (av1-2) and cumulative pore volume of tailings clay with w = 60% and after biochemical consolidation decreases at first and then increases, but the volume percentage of small pores first increases and then decreases. Quicklime solidification can expand soil pores and provide space for the microorganisms to survive, while the microbial mineralization fills soil pores and bonds with soil particles; therefore, biochemical consolidation will make the soil more compact. However, when the water content or quicklime content is too high, an intense hydration reaction releases a large amount of heat, making the temperature too high (up to 50.5 °C) and increasing the concentration of OH−. The excessive temperature and alkaline environment markedly inhibits the microbial activity, resulting in a large number of microbial death, and the biochemical consolidation effect is no longer apparent.

Hippocampal tail volume as a predictive biomarker of antidepressant treatment outcomes in patients with major depressive disorder: a CAN-BIND report.

Finding a clinically useful neuroimaging biomarker that can predict treatment response in patients with major depressive disorder (MDD) is challenging, in part because of poor reproducibility and generalizability of findings across studies. Previous work has suggested that posterior hippocampal volumes in depressed patients may be associated with antidepressant treatment outcomes. The primary purpose of this investigation was to examine further whether posterior hippocampal volumes predict remission following antidepressant treatment. Magnetic resonance imaging (MRI) scans from 196 patients with MDD and 110 healthy participants were obtained as part of the first study in the Canadian Biomarker Integration Network in Depression program (CAN-BIND 1) in which patients were treated for 16 weeks with open-label medication. Hippocampal volumes were measured using both a manual segmentation protocol and FreeSurfer 6.0. Baseline hippocampal tail (Ht) volumes were significantly smaller in patients with depression compared to healthy participants. Larger baseline Ht volumes were positively associated with remission status at weeks 8 and 16. Participants who achieved early sustained remission had significantly greater Ht volumes compared to those who did not achieve remission by week 16. Ht volume is a prognostic biomarker for antidepressant treatment outcomes in patients with MDD.

Accounting for tailings dam failures in the valuation of mining projects

The number of major tailings dam failures has doubled over the past 20 years, culminating in the tragic accident at Brumadinho in Brazil where about 300 people lost their lives. In this context, there is a growing demand from mining companies, institutional investors and policymakers alike for updated mining project assessment tools taking account of such risks. As part of this research, this paper develops a real option framework for evaluating mining projects involving tailings dams and their associated risk. Two options are considered beyond standard business-as-usual safety measures: reinforced dam maintenance, and retrofitting a treatment process that reduces the volume of unconsolidated tailings. A closed-form expression was obtained for the expected value of the business-as-usual case; semi-analytic formulas were obtained for the two options for evaluation by dynamic programming with quantization of the price factor. When applied to an iron ore deposit with characteristics similar to the Samarco deposit, the method shows that both options are financially superior to business-as-usual for the mining company, with the dry processing retrofitting option being the most attractive. The sensitivity of the expected values was evaluated over a range of values of the key parameters. This research provides senior decision-makers with tools to evaluate different options regarding tailings dam safety from a financial point of view, and provides financial evidence in favour of safer treatment processes for mining waste.

Complex cellular structures

We introduce the notion of a complex cell, a complexification of the cells/cylinders used in real tame geometry. For $\delta\in(0,1)$ and a complex cell $\mathcal{C}$ we define its holomorphic extension $\mathcal{C}\subset\mathcal{C}^\delta$, which is again a complex cell. The hyperbolic geometry of $\mathcal{C}$ within $\mathcal{C}^\delta$ provides the class of complex cells with a rich geometric function theory absent in the real case. We use this to prove a complex analog of the cellular decomposition theorem of real tame geometry. In the algebraic case we show that the complexity of such decompositions depends polynomially on the degrees of the equations involved. Using this theory, we refine the Yomdin-Gromov algebraic lemma on $C^r$-smooth parametrizations of semialgebraic sets: we show that the number of $C^r$ charts can be taken to be polynomial in the smoothness order $r$ and in the complexity of the set. The algebraic lemma was initially invented in the work of Yomdin and Gromov to produce estimates for the topological entropy of $C^\infty$ maps. For analytic maps our refined version, combined with work of Burguet, Liao and Yang, establishes an optimal refinement of these estimates in the form of tight bounds on the tail entropy and volume growth. This settles a conjecture of Yomdin who proved the same result in dimension two in 1991. A self-contained proof of these estimates using the refined algebraic lemma is given in an appendix by Yomdin. The algebraic lemma has more recently been used in the study of rational points on algebraic and transcendental varieties. We use the theory of complex cells in these two directions. In the algebraic context we refine a result of Heath-Brown on interpolating rational points in algebraic varieties. In the transcendental context we prove an interpolation result for (unrestricted) logarithmic images of subanalytic sets.

Individuals in the prediabetes stage exhibit reduced hippocampal tail volume and executive dysfunction

IntroductionHigh glucose levels are associated with cognitive impairment and total hippocampal volume reductions. However, the effects of the blood glucose level on hippocampal subfield volumes remain unclear, especially in the prediabetes stage.MethodsSixty participants were enrolled in this cross‐sectional study and were divided into the nondiabetes, prediabetes, and diabetes groups according to their medical history and A1c level. A full battery of neuropsychological tests was used to assess the global cognition, executive function, attention, verbal fluency, working memory, immediate memory, and delayed memory. FreeSurfer 6.0 was used for the hippocampus parcellation. Hippocampal subfield volumes were adjusted by intracranial volume. Analyses of covariance, multiple linear regression, and partial correlation analysis were used to explore the relationship between A1c level, cognitive function, and hippocampal subfields volume, in which age, sex, education years, body mass index, history of hypertension, level of cholesterol, and the presence of ApoE4‐positive status were adjusted.ResultsSignificant differences in the total left hippocampal volume (p = 0.046) and left hippocampal tail volume (p = 0.014) were noted among three groups. Significant correlation was identified between the A1c level and the volume of left hippocampal tail (r = −0.334, p = 0.009) after adjusting all the covariants. Increased A1c level was significantly associated with executive dysfunction, as assessed by trail making test B (R = 0.503, p = 0.0016) and Stroop test C (R = 0.506, p = 0.001).ConclusionsOur results support that the left hippocampal tail volume may be served as an early marker of diabetes‐related brain damage, associated with executive dysfunction. Clinicians should pay closer attention to adults in the prediabetes stage to prevent later cognitive impairment.

Phytostabilization of Zn and Cd in Mine Soil Using Corn in Combination with Biochars and Manure-Based Compost

Mining activities could produce a large volume of spoils, waste rocks, and tailings, which are usually deposited at the surface and become a source of metal pollution. Phytostabilization of the mine spoils could limit the spread of these heavy metals. Phytostabilization can be enhanced by using soil amendments such as manure-based biochars capable of immobilizing metal(loid)s when combined with plant species that are tolerant of high levels of contaminants while simultaneously improving properties of mine soils. However, the use of manure-based biochars and other organic amendments for mine spoil remediation are still unclear. In this greenhouse study, we evaluated the interactive effect of biochar additions (BA) with or without the manure-based compost (MBC) on the shoots biomass (SBY), roots biomass (RBY), uptake, and bioconcentration factor (BCF) of Zn and Cd in corn (Zea mays L.) grown in mine soil. Biochar additions consisting of beef cattle manure (BCM); poultry litter (PL); and lodge pole pine (LPP) were applied at 0, 2.5, and 5.0% (w/w) in combination with different rates (0, 2.5, and 5.0%, w/w) of MBC, respectively. Shoots and roots uptake of Cd and Zn were significantly affected by BA, MBC, and the interaction of BA and MBC. Corn plants that received 2.5% PL and 2.5% BCM had the greatest Cd and Zn shoot uptake, respectively. Corn plants with 5% BCM had the greatest Cd and Zn root uptake. When averaged across BA, the greatest BCF for Cd in the shoot of 92.3 was from the application of BCM and the least BCF was from the application of PL (72.8). Our results suggest that the incorporation of biochar enhanced phytostabilization of Cd and Zn with concentrations of water-soluble Cd and Zn lowest in soils amended with manure-based biochars while improving the biomass productivity of corn. Overall, the phytostabilization technique and biochar additions have the potential to be combined in the remediation of heavy metals polluted soils.

The effect of predator kairomones on caudal regeneration by Allegheny Mountain Dusky Salamanders (Desmognathus ochrophaeus)

Many prey use autotomy as an antipredator mechanism. Rapid regeneration of autotomized appendages is beneficial because forfeited tissues may serve as organs for energy storage, accessories for locomotion, or indicators of social status. We monitored levels of caudal regeneration by Allegheny Mountain Dusky Salamanders (Desmognathus ochrophaeus Cope, 1859) exposed to kairomones from predatory Eastern Garter Snakes (Thamnophis sirtalis (Linnaeus, 1758)). After the induction of autotomy, salamanders were exposed to one of three treatment regimens: blank (water), or acute (30 min per week) or chronic (constant) exposure to predator kairomones during a 12-week study period. Overall, the mean volume of regenerated tissue, as a percentage of the original tail volume, was highest for individuals exposed to the blank versus predator kairomones. When the combined effects of time elapsed since the induction of caudal autotomy and the different treatment regimens were considered, we found that the mean volume of regenerated tissue was significantly greater for control salamanders beginning 8 weeks after autotomy. The mechanism contributing to the differential rates of regeneration among individuals in our treatment groups is unknown, but previous work suggests that elevated stress related to predation threat can have detrimental effects on wound healing and growth in amphibians.