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1. Student attitudes and achievement in active learning calculus

   https://doi.org/10.1080/0020739X.2022.2150902  

   Duran, Pablo A; Castillo, Adam J; Watson, Charity; Fuller, Edgar; Potvin, Geoff; Kramer, Laird H (March 2024, International Journal of Mathematical Education in Science and Technology)

   The present paper explores the relationship between attitudes towards mathematics (ATM) and achievement in college calculus in active learning (AL) and lecture-based (LB) classrooms. Previous work on this relationship has mainly been limited to LB instruction, neglecting the impact of innovative approaches such as AL. Less attention has been paid to the roles played in this relationship by gender, year in college, and initial ATM. Results from a sample of 535 undergraduate students enrolled in 9 AL and 9 LB sections are presented. Data included ATMI surveys’ responses, final grades, and demographics. Correlation and multiple regression analyses were conducted. The influence of instruction on students with low ATM was also examined. Gender and year in college were the main demographic variables considered. Achievement in AL was found to be less dependent on initial ATM in terms of correlation. AL showed higher gains in grades than LB, when controlling for ATM and demographic variables. Effect sizes of AL instruction on grades of students with low ATM were larger than those of students with higher ATM. Furthermore, AL courses had a large effect size (d = 0.81) on female students with lower ATM, confirming its role as a gender equalizer. 

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2. Observation of low-resistance Al and Ni p-type ohmic contacts to dilute GeC and GeCSn alloys

   https://doi.org/10.1116/6.0003739  

   Saha, Jibesh K; Taqy, Saif_A A; Sarkar, Pallab K; Rahaman, Imteaz; Arbogast, Augustus W; Dey, Tuhin; Dolocan, Andrei; Reaz_Rahman_Munna, Md; Alam, Khorshed; Wasserman, Daniel; et al (December 2024, Journal of Vacuum Science & Technology B)

   Nickel and aluminum ohmic contacts were formed on p-doped GeC and GeCSn epitaxial films with ∼1%C. When a 40 nm p-GeC contact layer was added to p-Ge, annealed contact resistivity (Rc) dropped by 87% to 9.3 × 10−7 Ω cm2 for Al but increased by 32% to 2.9 × 10−5 Ω cm2 for Ni. On the other hand, thick films of GeCSn, which showed lower active doping, had contact resistivities of 4.4 × 10−6 Ω cm2 for Al and 1.4 × 10−5 Ω cm2 for Ni. In general, Al contacts were better than Ni, regardless of anneal, and were further improved by adding carbon. Annealing reduced Rc for both Ni and Al contacts to GeCSn by 4×, 2× for Al on GeC, and 5 orders of magnitude for Ni on GeC. It is speculated that C forms bonds with Ni that inhibit diffusion of Ni into the Ge, thus preventing the formation of low-resistance nickel germanide. Adding C, either as bulk GeCSn or as GeC contact layers, seems to significantly reduce the contact resistivity for Al contacts when compared to bulk Ge of comparable doping. 

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3. What do relationships between extractable metals and soil organic carbon concentrations mean?

   https://doi.org/10.1002/saj2.20343  

   Hall, Steven J.; Thompson, Aaron (January 2022, Soil Science Society of America Journal)

   Abstract Aluminum (Al)‐bearing and iron (Fe)‐bearing minerals, especially short‐range‐ordered (SRO) phases, are thought to protect soil organic C (SOC). However, it remains methodologically challenging to assess the influence of Al vs. Fe minerals or metal complexes. Whereas SRO Al and Fe phases share some properties, Al dissolved by oxalate (Al_ox) often correlates stronger with SOC than Fe dissolved by oxalate (Fe_ox) or citrate–dithionite (Fe_cd). To further evaluate these relationships, we analyzed a large North American soil dataset from the National Ecological Observatory Network. A strong relationship between Al_oxand SOC (and weaker Fe_ox‐SOC relationship) persisted even after excluding soils rich in SRO minerals (Andisols and Spodosols). Al dissolved by oxalate was strongly correlated with citrate–dithionite‐extractable Al (Al_cd; slope = 0.92,R² = .69), and discrepancies could be explained (R² = .87) by greater dissolution of Al‐substituted Fe phases by citrate–dithionite and greater dissolution of aluminosilicates by oxalate. Aluminum dissolved by oxalate and Al_cdwere both strong SOC predictors despite their differing relationships with silicon (Si). Al dissolved by oxalate and Si_oxstrongly covaried (R² = .79), but Al_cdwas inconsistently related to Si_cd(R² = .18). Similar relationships of Al_oxand Al_cdwith SOC, despite differences in minerals extracted by oxalate and citrate–dithionite, suggest that Al‐OC complexes (as opposed to aluminosilicate or iron‐bearing minerals) were the best SOC predictor. This raises important questions: do Al‐OC complexes indicate protection from decomposition or simply reflect greater intensity of mineral weathering by organic acids; and, if the latter, then perhaps SOC input is driving Al_oxand SOC correlations rather than Al phase composition or abundance. 

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4. Joint Effects of Lifestyle Habits and Heavy Metals Exposure on Chronic Stress Among U.S. Adults: Insights from NHANES 2017–2018

   https://doi.org/10.3390/jox15010007  

   Ogundipe, Esther; Obeng-Gyasi, Emmanuel (February 2025, Journal of Xenobiotics)

   Background: Chronic stress, characterized by sustained activation of physiological stress response systems, is a key risk factor for numerous health conditions. Allostatic load (AL), a biomarker of cumulative physiological stress, offers a quantitative measure of this burden. Lifestyle habits such as alcohol consumption and smoking, alongside environmental exposures to toxic metals like lead, cadmium, and mercury, were individually implicated in increasing AL. However, the combined impact of these lifestyle habits and environmental factors remains underexplored, particularly in populations facing co-occurring exposures. This study aims to investigate the joint effects of lifestyle habits and environmental factors on AL, using data from the NHANES 2017–2018 cycle. By employing linear regression and Bayesian Kernel Machine Regression (BKMR), we identify key predictors and explore interaction effects, providing new insights into how cumulative exposures contribute to chronic stress. Results from BKMR analysis underscore the importance of addressing combined exposures, particularly the synergistic effects of cadmium and alcohol consumption, in managing physiological stress. Methods: Descriptive statistics were calculated to summarize the dataset, and multivariate linear regression was performed to assess associations between exposures and AL. BKMR was employed to estimate exposure–response functions and posterior inclusion probabilities (PIPs), focusing on identifying key predictors of AL. Results: Descriptive analysis indicated that the mean levels of lead, cadmium, and mercury were 1.23 µg/dL, 0.49 µg/dL, and 1.37 µg/L, respectively. The mean allostatic load was 3.57. Linear regression indicated that alcohol consumption was significantly associated with increased AL (β = 0.0933; 95% CI [0.0369, 0.1497]; p = 0.001). Other exposures, including lead (β = −0.1056; 95% CI [−0.2518 to 0.0408]; p = 0.157), cadmium (β = −0.0001, 95% CI [−0.2037 to 0.2036], p = 0.999), mercury (β = −0.0149; 95% CI [−0.1175 to 0.0877]; p = 0.773), and smoking (β = 0.0129; 95% CI [−0.0086 to 0.0345]; p = 0.508), were not significant. BKMR analysis confirmed alcohol’s strong importance for AL, with a PIP of 0.9996, and highlighted a non-linear effect of cadmium (PIP = 0.7526). The interaction between alcohol and cadmium showed a stronger effect on AL at higher exposure levels. In contrast, lead, mercury, and smoking demonstrated minimal effects on AL. Conclusions: Alcohol consumption and cadmium exposure were identified as key contributors to increased allostatic load, while other exposures showed no significant associations. These findings emphasize the importance of addressing lifestyle habits and environmental factors in managing physiological stress. 

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5. Supersolvus Hot Workability and Dynamic Recrystallization in Wrought Co–Al–W-Base Alloys.

   https://doi.org/10.1007/978-3-030-51834-9_84  

   Wertz, K.; Weaver, D.; Wen, D.; Titus, M.S.; Shivpuri, R.; Niezgoda, S.R.; Mills, M.J.; Semiatin, S.L. (January 2020, Superalloys 2020)

   Gamma-prime strengthened Co–Al–W-based superalloys offer a unique combination of weldability, mechanical strength, creep resistance, and environmental resistance at temperature—leading many to consider the system as an alternative to nickel-base superalloys for future generation turbine engine hardware. However, little information exists regarding the deformation processing required to turn these novel alloys into useable product forms with appropriate microstructure refinement. Supersolvus thermomechanical processing sequences were successfully demonstrated using right-cylindrical upset specimens for two wrought γ′-strengthened cobalt-base superalloys at industrially relevant temperatures and deformation rates. Hot flow behavior and microstructure evolution were quantitatively characterized and compared to available information on a legacy nickel-base system, Waspaloy. Further, density functional theory was used to explore the compositional dependency of the intrinsic material properties influencing single-phase hot working behavior of model Ni–Al binary and Co–Al–W ternary systems. The apparent similarity in the supersolvus thermomechanical processing behavior of Co–Al–W-base systems and their two-phase γ–γ′ Ni-base counterparts suggests conventional pathways, models, and equipment may be leveraged to speed transition and implementation of wrought Co–Al–W-base alloys for components where their properties may be advantageous. 

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