Fluctuation-Driven Molecular Transport in an Asymmetric Membrane Channel

Channel proteins, that selectively conduct molecules across cell membranes, often exhibit an asymmetric structure. By means of a stochastic model, we argue that channel asymmetry in the presence of non-equilibrium fluctuations, fueled by the cell's metabolism as observed recently, can dramatically influence the transport through such channels by a ratchet-like mechanism. For an aquaglyceroporin that conducts water and glycerol we show that a previously determined asymmetric glycerol potential leads to enhanced inward transport of glycerol, but for unfavorably high glycerol concentrations also to enhanced outward transport that protects a cell against poisoning.Comment: REVTeX4, 4 pages, 3 figures; Accepted for publication in Phys. Rev. Let

Water constraints on European power supply under climate change: Impacts on electricity prices

Recent warm, dry summers showed the vulnerability of the European power sector to low water availability and high river temperatures. Climate change is likely to impact electricity supply, in terms of both water availabilty for hydropower generation and cooling water usage for thermoelectric power production. Here, we show the impacts of climate change and changes in water availability and water temperature on European electricity production and prices. Using simulations of daily river flows and water temperatures under future climate (2031-2060) in power production models, we show declines in both thermoelectric and hydropower generating potential for most parts of Europe, except for the most northern countries. Based on changes in power production potentials, we assess the cost-optimal use of power plants for each European country by taking electricity import and export constraints into account. Higher wholesale prices are projected on a mean annual basis for most European countries (except for Sweden and Norway), with strongest increases for Slovenia (12-15%), Bulgaria (21-23%) and Romania (31-32% for 2031-2060), where limitations in water availability mainly affect power plants with low production costs. Considering the long design life of power plant infrastructures, short-term adaptation strategies are highly recommended to prevent undesired distributional and allocative effects

Pushing forward white lupin as a local source for protein and nitrogen in Central Europe

White lupin (Lupinus albus L.) is a promising leguminous crop. Europe is fully dependent on protein and nitrogen fertilizer imports. This has tremendous negative effects both in Europe and the producing countries, such as loss of terrestrial biodiversity, pollution of freshwater, increase of greenhouse gases and soil acidification. Diverse crop-rotations with a substantial amount of pulses are a proven solution. The protein composition and yield potential of white lupin suggest that it could become the ‘Soy of the North’. Currently, the seed-borne pathogen Colletotrichum lupini is substantially impeding the cultivation of white lupin in Central Europe. We developed a DNA-based diagnostic test to identify and quantify the fungal pathogen in plants and seeds. This technique will allow us to improve our understanding of the Colletotrichum lupini life cycle and, thereby, lay the basis for an advanced resistance breeding approach

Effects of Feeding Field Peas on Fresh Beef Quality

The objective of this study was to evaluate the use of field peas during two phases of production (grazing and finishing) on fresh beef quality. A total of 232 crossbred steers and heifers were randomly assigned to one of six dietary treatments in a 3x2 factorial consisting of 3 pasture and 2 finishing supplementations. The pasture phase consisted of 1) no supplement, 2) field peas at 0.5% BW, or 3) dry-rolled corn supplement at 0.5% of BW. The finishing phase consisted of 1) field peas at 20% DM or 2) no field peas. During this two-year study, steers (year 1) and heifers (year 2), strip loin samples were aged for 14 d. Steaks were subject to retail display for a total of 7 d. Analyses included tenderness (WBSF and SSF), objective (L*, a*, and b*) and subjective color, lipid oxidation (TBARS) and fatty acid composition. There were minimal effects due to diet. Dietary treatment had no effect on tenderness (WBSF or SSF) or content of saturated fatty acids, unsaturated fatty acids, monounsaturated fatty acids or polyunsaturated fatty acids (p \u3e 0.05). Although there was a significant interaction between pasture and finishing treatments for fatty acid C15:1 (p = 0.0331), the range in values was relative low and no implications from these differences could be identified. Supplementing cattle on pasture with field peas resulted in more C18:2 (p = 0.0381) fatty acids than when cattle were supplemented with corn, while cattle without supplement were intermediate. Meat from cattle finished with field peas had slightly greater lipid oxidation than samples from cattle not receiving field peas during finishing (1.56 vs. 1.44 mg malonaldehyde/kg tissue, respectively; p = 0.0541). Discoloration, L*, and a* displayed a triple interactions for retail display, pasture and finishing diets (p \u3c 0.0001, p = 0.0524 and p = 0.024, respectively). Although these interactions were statistically significant, no consistent patterns could be identified. These data indicate field peas may be used for cattle with minimal negative impact on fresh meat quality. Advisor: Chris Calkin

Numerical Characterization and Modeling of Adiabatic Slot Film Cooling

Film cooling is a technique used to protect critical surfaces in combustors, thrust chambers, turbines and nozzles from hot, chemically reacting gases. Accurately predicting the film's performance is especially challenging in the vicinity of the wall and the film injection plane due to the complex interactions of two highly turbulent, shearing, boundary layer flows. Properly characterizing the streams at the inlet of a numerical simulation and the choice of turbulence model are crucial to accurately predicting the decay of the film. To address these issues, this study employs a RANS solver that is used to model a film cooled wall. Menter's baseline model, and shear-stress transport model and the Spalart-Allmaras model are employed to determine the effect on film cooling predictions. Several methods for prescribing the inlet planes are explored. These numerical studies are compared with experimental data obtained in a UMD film cooling wind tunnel

Effects of Feeding Field Peas on Fresh Beef Quality

The objective of this study was to evaluate the use of field peas during two phases of production (grazing and finishing) on fresh beef quality. A total of 232 crossbred steers and heifers were randomly assigned to one of six dietary treatments in a 3x2 factorial consisting of 3 pasture and 2 finishing supplementations. The pasture phase consisted of 1) no supplement, 2) field peas at 0.5% BW, or 3) dry-rolled corn supplement at 0.5% of BW. The finishing phase consisted of 1) field peas at 20% DM or 2) no field peas. During this two-year study, steers (year 1) and heifers (year 2), strip loin samples were aged for 14 d. Steaks were subject to retail display for a total of 7 d. Analyses included tenderness (WBSF and SSF), objective (L*, a*, and b*) and subjective color, lipid oxidation (TBARS) and fatty acid composition. There were minimal effects due to diet. Dietary treatment had no effect on tenderness (WBSF or SSF) or content of saturated fatty acids, unsaturated fatty acids, monounsaturated fatty acids or polyunsaturated fatty acids (p \u3e 0.05). Although there was a significant interaction between pasture and finishing treatments for fatty acid C15:1 (p = 0.0331), the range in values was relative low and no implications from these differences could be identified. Supplementing cattle on pasture with field peas resulted in more C18:2 (p = 0.0381) fatty acids than when cattle were supplemented with corn, while cattle without supplement were intermediate. Meat from cattle finished with field peas had slightly greater lipid oxidation than samples from cattle not receiving field peas during finishing (1.56 vs. 1.44 mg malonaldehyde/kg tissue, respectively; p = 0.0541). Discoloration, L*, and a* displayed a triple interactions for retail display, pasture and finishing diets (p \u3c 0.0001, p = 0.0524 and p = 0.024, respectively). Although these interactions were statistically significant, no consistent patterns could be identified. These data indicate field peas may be used for cattle with minimal negative impact on fresh meat quality. Advisor: Chris Calkin

The Disenfranchised Grief of a Blackbird: Teacher Discernment, Introspection, and Healing through Autoethnography

Throughout my life, grief’s torrents have run undercurrent to my personal and professional journey. It has taken my arrival to mid-life, decades of professional and life experiences as well as higher education for this awareness to flow. I have been grieving for my lost self as woman; my shattered voice as a teacher; and the freedom to choose as a daughter of this nation. Utilizing a Marxist feminist lens, I will examine how patriarchal loss and capitalistic constructs rooted in an undeveloped class consciousness have perpetuated my own sense of powerlessness, detachment, and compulsivity, reifying my indoctrination into the teaching profession (Apple, 1988, 2019; Gilligan & Snider, 2018; Seeman, 1959). Coming into this awareness has been the work of discernment whereas healing has been the result of grief work (Boyd & Myers, 1988). This dissertation is an examination my of lived experiences with disenfranchised grief and subsequent transformational learning within my personal, professional, and pedagogical intersectionality. Storying my way within these concentric spheres through autoethnography, a healing methodology, I will examine dialectically how my positionality intersect with my profession and pedagogy, perpetuating grief while promoting healing (Chang, 2008; Ellis et al., 2011; Pennebaker & Evans, 2014; Pennebaker & Smyth, 2016; Poulos, 2021). To shed light on disenfranchisement within any context, voices from the culture itself must rise up; silences must rupture (Adams et al., 2014). Stories must be shared to shed light on the struggles, and they must be accessible to reach the intended audience— educators from K-12, adult education, and higher education (Adams et al., 2014, Chang, 2008; Holman Jones et al., 2013; Poulos, 2013). It is my hope that by sharing my story, my lived experiences, others will shatter their own silences and heal with me