Showing papers by "Southern Illinois University Carbondale published in 2023"

Heat hardening of a larval amphibian is dependent on acclimation period and temperature

Abstract: Plasticity in heat tolerance provides ectotherms the ability to reduce overheating risk during thermal extremes. However, the tolerance–plasticity trade-off hypothesis states that individuals acclimated to warmer environments have a reduced plastic response, including hardening, limiting their ability to further adjust their thermal tolerance. Heat hardening describes the short-term increase in heat tolerance following a heat shock that remains understudied in larval amphibians. We sought to examine the potential trade-off between basal heat tolerance and hardening plasticity of a larval amphibian, Lithobates sylvaticus, in response to differing acclimation temperatures and periods. Lab-reared larvae were exposed to one of two acclimation temperatures (15°C and 25°C) for either 3 or 7 days, at which time heat tolerance was measured as critical thermal maximum (CTmax). A hardening treatment (sub-critical temperature exposure) was applied 2 h before the CTmax assay for comparison to control groups. We found that heat-hardening effects were most pronounced in 15°C acclimated larvae, particularly after 7 days of acclimation. By contrast, larvae acclimated to 25°C exhibited only minor hardening responses, while basal heat tolerance was significantly increased as shown by elevated CTmax temperatures. These results are in line with the tolerance–plasticity trade-off hypothesis. Specifically, while exposure to elevated temperatures induces acclimation in basal heat tolerance, shifts towards upper thermal tolerance limits constrain the capacity for ectotherms to further respond to acute thermal stress.

Examining the comparability of parallel English and Chinese elicited imitation tasks

Abstract: The suite of elicited imitation tasks (EITs) developed originally by Ortega et al. (2002) has been validated as an effective measure of second language (L2) proficiency and adopted in different L2 studies. However, the comparability of the crosslinguistic parallel EITs, all developed based on the English version, has yet to be explored. This exploratory study investigated the comparability of Ortega et al.’s parallel English and Chinese EITs by analyzing L2 English data collected from 82 L2 English participants in Wu et al. (2022) and L2 Chinese data collected from 80 L2 Chinese participants in Wu and Ortega (2013). Despite the crosslinguistic variation observed between the English and Chinese EITs, the converging evidence gathered from internal consistency, item discriminatory power, correlations with external proficiency measures, and abilities to discriminate four speaking levels indicates that the two parallel EITs tap roughly the same language proficiency components in each language. Crucially, the classification drawn from the same CAF measures across both languages suggests that the five proficiency levels of the EIT scores (i.e., Novice = 0–24; Low = 25–48; Intermediate = 49–72; High = 73–96; Advanced = 97–120) can consistently discriminate language abilities into distinctive levels across both languages. We hope the proposed five proficiency levels will enhance the application and interpretation ability of Ortega et al.’s parallel EITs in crosslinguistic, bilingual, and multilingual research.

Frontispiz: Anomalously Large Antiphase Signals from Hyperpolarized Orthohydrogen Using a MOF‐Based SABRE Catalyst

Abstract: NMR Spectroscopy. In their Communication (e202213581), Boyd M. Goodson et al. report the addition of parahydrogen to particles comprised of an iridium-based catalyst on a metal-organic framework to produce orthohydrogen. A strongly hyperpolarized state is achieved.

On Design of Robust Linear Quadratic Regulators

Abstract: Closed-loop stability of uncertain linear systems is studied under the state feedback realized by a linear quadratic regulator (LQR). Sufficient conditions are presented that ensure the closed-loop stability in the presence of uncertainty, initially for the case of a non-robust LQR designed for a nominal model not reflecting the system uncertainty. Since these conditions are usually violated for a large uncertainty, a procedure is offered to redesign such a non-robust LQR into a robust one that ensures closed-loop stability under a predefined level of uncertainty. The analysis of this paper largely relies on the concept of inverse optimal control to construct suitable performance measures for uncertain linear systems, which are non-quadratic in structure but yield optimal controls in the form of LQR. The relationship between robust LQR and zero-sum linear quadratic dynamic games is established.

Cross-Comparisons of Sediment Incubation Methods to Bound Stochastic Influences on Denitrification of Natural Waters from Mississippi River Floodplain Wetlands

Abstract: Flood regimes in large river systems such, as the Mississippi River, are inherently stochastic meaning that floodplain wetlands experience varying hydrostatic pressures of groundwater upwelling (exfiltration) and infiltration from overland flooding. Distinctions in water delivery can drastically alter the oxygen levels and groundwater delivery into wetland sediments where anaerobic microbes remove nitrates through denitrification. Our findings bound conditions for modeling denitrification rates across oxic flood waters versus exfiltration by anoxic groundwaters. Four-by-four factorial laboratory incubation treatments included oxic versus anoxic waters (degassed with helium) introduced by exfiltration or infiltration (Figs. 1A, 1B).Sediments collected in triplicate from four floodplain wetlands located along Dogtooth Bend segment of the Mississippi River near the Ohio River confluence were incubated with river water. Sediments were incubated at 29 oC for 96 h. Nitrogen gas production was measured by membrane inlet mass spectrometry (MIMS). Inflow and outflow waters were analyzed for nitrate, ammonia, phosphate, and dissolved organic carbon while sediments were characterized for their physical traits. In contrast to most studies, that estimate denitrification relative to surface area in incubations only (i.e. address conditions of surface flooding), we also present our findings relative to sediment volumes (i.e. evaluate denitrification rates from exfiltration of groundwater). Regression analyses compared denitrification from surface area versus volume calculations (R2 values > 0.89); consequently providing an excellent tool for converting estimates from surface area alone to varying sediment saturation for more rigorous assessments of subsurface interactions.Average denitrification rates relative to sediment volume were significantly higher in anoxic-deep-injection cores (&#8220;AD cores&#8221;; 23.83 + 1.94 N mg/m3/d) compared to anoxic-surface-delivery cores (&#8220;AS cores&#8221;; 19.98 + 1 N mg/m3/d), that also exceeded oxic-deep-injection cores (&#8220;OD cores"; 14.96 + 1.78 N mg/m3/d) and oxic-surface-delivery cores (&#8220;OS cores&#8221;; 10.23 + 1.04 N mg/m3/d). Thus, average denitrification followed an anoxic-injection hierarchy of AD > AS > OD > OS (p-values < 0.003), which was maintained for denitrification relative to surface area. Regarding site-specific distinctions, for sandy sites this hierarchy persisted, and each treatment differed significantly. Sites with clayey sediments had very-low permeability regardless of injection type; thus only oxic versus anoxic treatments differed significantly irrespective of water delivery. By contrast sites with loamy sediments, injection type significantly influenced denitrification rates while neither oxic nor anoxic water treatments differed. An AICc model showed that phosphate, ammonia, temperature variation, dissolved oxygen, and sand content explained 33% (p-value < 0.05) of the variation in denitrification rates across all cores and treatments.Our findings highlight the greater insights provided from cross-comparison incubation designs to better inform landscape-scale models of denitrification rates across floodplain wetlands depending on the magnitude and duration of flooding.

Perception of human rights, law enforcement interference and justifiability of terrorism: a Cross-National Analysis

Abstract: This paper seeks to understand how subjective perceptions of human rights influence the justifiability of terrorism at the individual level, net of individual and country-level controls. Utilizing the seventh wave of World Values Survey data and 65,668 respondents from 52 countries, this study finds those who report greater interference in their lives from security agents and those who see the country as being run more democratically are more likely to find terrorism justified, while those who perceive less respect for human rights are less likely to do so. The effect of state terror on the justifiability of terrorism is moderated by perceived democracy, with those perceiving the country as being run more democratically being more likely to find terrorism justified when state terror is high.

Autoethnography: storied scholarship

Abstract: Autoethnography articulates the intersection of cognitive and somatic experience. Through narrative craft, it stories a life lived, and in so doing, engages theory to make sense of how that life is socio-historically situated. It demonstrates the systemic consequences on everyday interactions, while simultaneously showing how a constellation of interactions both sustain and change those very systems. Importantly, autoethnography provides a snapshot of understanding and critique, embodying Fisher's (1984) description of homo narrans (p. 6), humans as narrating (and narrated) beings. In this chapter, I briefly trace the history of autoethnography. I then explicate the notion of autoethnographic voice, while overviewing common instantiations of voice in autoethnographic work. I outline the evocative element of autoethnography before identifying the sort of content that autoethnographers write about. I end by providing a snapshot of where one might look to further explore autoethnography as research practice.

<i>Diels–Alder</i> Additions to 2,2’‐Biaceanthrylene

Abstract: A series of Diels–Alder reactions between the diene 2,2’-biaceanthrylene and several dienophiles is presented. The diene is a cyclopenta-fused polycyclic aromatic hydrocarbon with anthracene units linked by two cyclopentene rings. Depending on the dienophile, the major product was the result of a single addition (dimethyl acetylenedicarboxylate) or double addition (quinone, benzyne) to the diene. Single crystal X-ray analysis of the quinone-derivative shows a propeller-like structure composed of mixed enantiomers. The synthesis and photophysical properties of these compounds are presented.

Iron (oxyhydr)oxide concretion formation: New insights from southern Utah, USA

Abstract: Iron (oxyhydr)oxide concretions are cemented mineral masses formed via authigenic cements in sedimentary rocks at any time during diagenesis (syndepositional, burial, and late-stage). These features are common in porous and permeable sandstone and even present on Mars in at least two different locations and formations. One notable study area for the spherules is within the Navajo Sandstone in the Grand Staircase Escalante National Monument (GSENM) in southern Utah. Diagenetic concretions, particularly iron (oxyhydr)oxide mineralogies, are thought to form via a two-fluid mixing model where one fluid has the reactants in solution, then another fluid meets and mixes with the reactant-bearing fluid, and the concretions precipitate. These two fluids could be a reducing fluid that mobilizes iron as Fe2+ and then mixes with an oxidizing fluid to precipitate iron oxyhydr(oxide), but an acidic fluid could mobilize iron as Fe3+ and then interact with a neutral fluid for the same result.&#160; Another proposed model for iron (oxyhydr)oxide concretions calls for calcium carbonate precursor concretions and mobilization of iron by acidic fluids. The acidic, iron-bearing fluid then dissolves the carbonate concretion, which buffers the solution enough to precipitate iron oxyhydr(oxide) in the same morphology as the original calcite concretion. Our research shows that in GSENM, iron concretions and calcite concretions are present within the same stratigraphic horizon and in close proximity. Another field observation is the presence of calcite concretions in clusters along paleo water tables, rather than dispersed in a self-organized spacing within three dimensions like the iron features. Also present within the region are concretions with manganese oxide phases and the iron concretions tend to include manganese oxide, but not calcite. Calcite concretions do commonly contain some iron (oxyhydr)oxides, particularly as rims around grains. In the Entrada Sandstone, also in southern Utah, iron concretions are precipitated from fluid brought in with an igneous intrusion that mobilized the iron within the host rock. Structures in the area acted as baffles keeping the fluid stagnant and iron (oxyhydr)oxide concretions are only present between the igneous dike and the nearest baffle. Calcite concretions in the area are dispersed throughout the host rock (both within and outside of the baffles), suggested that mineral precipitation rates control concretion formation and that iron (oxyhydr)oxide concretions need a longer period of fluid stagnation for formation than do calcite concretions. Understanding the complex formation mechanisms can help to unravel the history of diagenetic fluids of varying chemistries and therefore, the habitability of subsurface environments on both Earth and Mars.

Frontispiece: Anomalously Large Antiphase Signals from Hyperpolarized Orthohydrogen Using a MOF‐Based SABRE Catalyst

Abstract: NMR Spectroscopy. In their Communication (e202213581), Boyd M. Goodson et al. report the addition of parahydrogen to particles comprised of an iridium-based catalyst on a metal–organic framework to produce orthohydrogen. A strongly hyperpolarized state is achieved.

Decoupling Redox Hopping and Catalysis in Metal‐Organic Frameworks ‐based Electrocatalytic CO ₂ Reduction

Abstract: Traditional MOF e-CRR, constructed from catalytic linkers, manifest a kinetic bottleneck during their multi-electron activation. Decoupling catalysis and charge transport can address such issues. Here, we build two MOF/e-CRR systems, [email protected] and TPP(Co)@NU-1000, by installing cobalt metalated phthalocyanine and tetraphenylporphyrin electrocatalysts within the redox active NU-1000 MOF. For [email protected], the e-CRR responsive CoI/0 potential is close to that of NU-1000 reduction compared to the TPP(Co)@NU-1000. Efficient charge delivery, defined by a higher diffusion (Dhop=4.1×10−12 cm2 s−1) and low charge-transport resistance ( =59.5 Ω) in [email protected] led FECO=80 %. In contrast, TPP(Co)@NU-1000 fared a poor FECO=24 % (Dhop=1.4×10−12 cm2 s−1 and =91.4 Ω). For such a decoupling strategy, careful choice of the host framework is critical in pairing up with the underlying electrochemical properties of the catalysts to facilitate the charge delivery for its activation.

Monitoring Algal Blooms in Small Lakes Using Drones: A Case Study in Southern Illinois

Abstract: Harmful Algal Blooms (HABs) persist in many water bodies around the world and pose adverse health and economic impacts to the affected communities. Small Unmanned Aerial Vehicles (UAVs) have recently been applied as a cost-effective tool for HABs monitoring. In this study, HABs in two small lakes in Southern Illinois (Carbondale Reservoir and the Campus Lake of Southern Illinois University) were monitored using UAVs and biomass concentrations in lake waters. By analyzing vegetation indices derived from multispectral UAV images and chlorophyll-a concentrations in the two lakes, statistical regression models were established for each waterbody. The model relates spectral characteristics of the lake water to its algae biomass. It was found that normalized difference vegetation index (NDVI) and blue-to-green band ratio are the best-fit indices to the variation in chlorophyll-a in Carbondale Reservoir and the Campus Lake, respectively. The findings in this study can be used for monitoring HABs using UAVs in these lakes in the future.

Projected Future Flooding Pattern of Wabash River in Indiana and Fountain Creek in Colorado: An Assessment Utilizing Bias-Corrected CMIP6 Climate Data

Abstract: Climate change is considered one of the biggest challenges around the globe as it has been causing alterations in hydrological extremes. Climate change and variability have an impact on future streamflow conditions, water quality, and ecological balance, which are further aggravated by anthropogenic activities such as changes in land use. This study intends to provide insight into potential changes in future streamflow conditions leading to changes in flooding patterns. Flooding is an inevitable, frequently occurring natural event that affects the environment and the socio-economic structure of its surroundings. This study evaluates the flooding pattern and inundation mapping of two different rivers, Wabash River in Indiana and Fountain Creek in Colorado, using the observed gage data and different climate models. The Coupled Model Intercomparison Project Phase 6 (CMIP6) streamflow data are considered for the future forecast of the flood. The cumulative distribution function transformation (CDF-t) method is used to correct bias in the CMIP6 streamflow data. The Generalized Extreme Value (L-Moment) method is used for the estimation of the frequency of flooding for 100-year and 500-year return periods. Civil GeoHECRAS is used for each flood event to map flood extent and examine flood patterns. The findings from this study show that there will be a rapid increase in flooding events even in small creeks soon in the upcoming years. This study seeks to assist floodplain managers in strategic planning to adopt state-of-the-art information and provide a sustainable strategy to regions with similar difficulties for floodplain management, to improve socioeconomic life, and to promote environmental sustainability.

Melt Production beneath subduction zones: Using numerical models to evaluate melt production under batch and fractional melt conditions

Abstract: Melt production at subduction zones depends on numerous variables, including mineral composition, water content, age of the plate, dip angle of the plate subducting, rate of convergence, age of the slab, and forearc dimensions. To evaluate the importance of individual variables and their interaction with each other, we constructed 2D numerical models of subduction, tracking temperature, mantle flow, and melt production. This project examines differences in batch and fractional melting sensitivity to the changes of the different variables. Variables include modal clinopyroxene (cpx) and its exhaustion, mantle hydration, dip angle, convergence rate, and forearc depth. Models tracked total melt as parameters were altered. For this project, the dip angle of the slab varied from 45 to 60&#176;, rate of the slab between 20 and 90 km/Myr, age of the plate between 20 and 90 Myr, forearc depth between 40-50 km, and hydration between 0.01 and 0.1 wt%. The slab age and initial modal cpx levels are held constant throughout all the trials at 60 Myr and 15%, respectively. With batch melting, melting peaks for models set with hydration content > 0.1%, a dip angle at 60&#176;, the highest convergence rates, and the youngest ages. Melting decreases with greater ages and lower convergence rates. In both fractional and batch melting, increasing the hydration leads to an increase in melt production overall. For fractional melting with hydration less than 0.05wt%, the difference in amount of melt compared to batch melting is negligible. At greater initial hydration the difference becomes greater with less produced under fractional melting. Changes in forearc extent also affect total melt with longer forearcs resulting in less melt than shorter ones. Additionally, we explored the effects of permeability on the melt production. Most notably, a secondary region of melt begins to form for when permeability is about 0.02 or greater. The secondary region encompasses melting above the harzburgite solidus. While two melting regions were nearly always observed under batch melt conditions, typically only one region of melting was observed under fractional melt conditions. In both cases, hydration and the dip of subducting slab have the most effect on melt production, while the convergence rate and the depth of the forearc have a smaller effect on melt production.