Timescales for the development of methanogenesis and free gas layers in recently-deposited sediments of Arkona Basin (Baltic Sea)

Arkona Basin (southwestern Baltic Sea) is a seasonally-hypoxic basin characterized by the presence of free methane gas in its youngest organic-rich muddy stratum. Through the use of reactive transport models, this study tracks the development of the methane geochemistry in Arkona Basin as this muddy sediment became deposited during the last 8 kyr. Four cores are modeled each pertaining to a unique geochemical scenario according to their respective contemporary geochemical profiles. Ultimately the thickness of the muddy sediment and the flux of particulate organic carbon are crucial in determining the advent of both methanogenesis and free methane gas, the timescales over which methanogenesis takes over as a dominant reaction pathway for organic matter degradation, and the timescales required for free methane gas to form

Role of the inter‐ply microstructure in the consolidation quality of high‐performance thermoplastic composites

Consolidation of Carbon Fiber (CF)/high-performance thermoplastic compos-ites is much less understood than the one of their thermoset counterparts. It isusually assumed that the consolidation quality is directly linked to the removalof voids within the sample during consolidation, leading to mechanical proper-ties suitable for aerospace applications. A systematic study of the temporalevolution of CF/polyetherketoneketone (PEKK) samples' microstructure con-solidated under low pressure in a rheometer is related to the increase in inter-laminar shear strength. The results show that despite similar void contentswell-below 1 vol%, samples can present significant differences in ILSS values,from 80 to 95 MPa for cross-ply samples, and from 98 to 112 MPa for unidirec-tional (UD) ones. A microstructural analysis shows that, for these materials,consolidation quality is rather related to a reorganization of the inter-ply, aresin-rich ( 70 vol%) region of typical thickness 10μm which is slowly repo-pulated in fibers during consolidation

Proteomic analysis of Arabidopsis glutathione S-transferases from benoxacor- and copper-treated seedlings

Glutathione S-transferases (GSTs) are involved in many stress responses in plants, for example, participating in the detoxification of xenobiotics and limiting oxidative damage. Studies examining the regulation of this gene family in diverse plant species have focused primarily on RNA expression. A proteomics method was developed to identify GSTs expressed in Arabidopsis seedlings and to determine how the abundance of these proteins changed in response to copper, a promoter of oxidative stress, and benoxacor, a herbicide safener. Eight GSTs were identified in seedlings grown under control conditions, and only one, AtGSTU19, was induced by benoxacor. In contrast, four GSTs, AtGSTF2, AtGSTF6, AtGSTF7, and AtGSTU19, were significantly more abundant in copper-treated seedlings. The different responses to these treatments may reflect the potential for copper to affect many more aspects of plant growth and physiology compared with a herbicide safener. Differences between RNA and protein expression of GSTs indicate that both transcriptional and translational mechanisms are involved in regulation of GSTs under these conditions

Report: The 62nd Annual Caddo Conference and 27th Annual East Texas Archeological Conference, Tyler, Texas, February 28 and 29, 2020

The 62nd Caddo Conference and 27th East Texas Archeological Conference was held at the University Center on the campus of the University of Texas at Tyler on February 28 and 29, 2020. The conference was dedicated to the rebuilding of public facilities at Caddo Mounds State Historic Site. These facilities had been destroyed by a tornado in 2019. The conference organizers were Thomas Guderjan, Colleen Hanratty, Cory Sills, Christy Simmons (University of Texas at Tyler), Keith Eppich (Tyler Junior College), Anthony Souther (Caddo Mounds State Historic Site), Amanda Regnier (Oklahoma Archeological Survey), Mark Walters (Texas Historical Commission Steward). Sponsors included The Center for Social Science Research and Department of Social Sciences, University of Texas at Tyler, Humanities Texas, Kevin Stingley, Arkansas Archeological Survey, Beta Analytic, Inc., Friends of Northeast Texas Archeology, East Texas Archeological Society, Maya Research Program, Tejas Archeology, Tyler Junior College, Gregg County Historical Museum, the American Indian Heritage Day of Texas organization, and the Caddo Nation. Before the formal program began, a preconference gathering was held at ETX Brewing Company at 221 S Broadway Avenue in Tyler on Thursday evening, February 27th. Approximately 250 people participated in the joint conferences

Amplitude equations for Rayleigh-Benard convective rolls far from threshold

An extension of the amplitude method is proposed. An iterative algorithm is developed to build an amplitude equation model that is shown to provide precise quantitative results even far from the linear instability threshold. The method is applied to the study of stationary Rayleigh-Benard thermoconvective rolls in the nonlinear regime. In particular, the generation of second and third spatial harmonics is analyzed. Comparison with experimental results and direct numerical calculations is also made and a very good agreement is found.Peer reviewe

Simulating Flaring Events in Complex Active Regions Driven by Observed Magnetograms

We interpret solar flares as events originating from active regions that have reached the Self Organized Critical state, by using a refined Cellular Automaton model with initial conditions derived from observations. Aims: We investigate whether the system, with its imposed physical elements,reaches a Self Organized Critical state and whether well-known statistical properties of flares, such as scaling laws observed in the distribution functions of characteristic parameters, are reproduced after this state has been reached. Results: Our results show that Self Organized Criticality is indeed reached when applying specific loading and relaxation rules. Power law indices obtained from the distribution functions of the modeled flaring events are in good agreement with observations. Single power laws (peak and total flare energy) as well as power laws with exponential cutoff and double power laws (flare duration) are obtained. The results are also compared with observational X-ray data from GOES satellite for our active-region sample. Conclusions: We conclude that well-known statistical properties of flares are reproduced after the system has reached Self Organized Criticality. A significant enhancement of our refined Cellular Automaton model is that it commences the simulation from observed vector magnetograms, thus facilitating energy calculation in physical units. The model described in this study remains consistent with fundamental physical requirements, and imposes physically meaningful driving and redistribution rules.Comment: 14 pages; 12 figures; 6 tables - A&A, in pres

Adaptive partitioning of real-time tasks on multiple processors

This paper presents a new algorithm for scheduling real-time tasks on multiprocessor/multicore systems. This new algorithm is based on combining EDF scheduling with a migration strategy that moves tasks only when needed. It has been evaluated through an extensive set of simulations that showed good performance when compared with global or partitioned EDF: a worst-case utilisation bound similar to partitioned EDF for hard real-time tasks, and a tardiness bound similar to global EDF for soft real-time tasks. Therefore, the proposed scheduler is effective for dealing with both soft and hard real-time workloads

Nanotopography-Induced Structural Anisotropy and Sarcomere Development in Human Cardiomyocytes Derived from Induced Pluripotent Stem Cells

This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Appl Mater Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://doi.org/10.1021/acsami.5b11671.Understanding the phenotypic development of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) is a prerequisite to advancing regenerative cardiac therapy, disease modeling, and drug screening applications. Lack of consistent hiPSC-CM in vitro data can be largely attributed to the inability of conventional culture methods to mimic the structural, biochemical, and mechanical aspects of the myocardial niche accurately. Here, we present a nanogrid culture array comprised of nanogrooved topographies, with groove widths ranging from 350 to 2000 nm, to study the effect of different nanoscale structures on the structural development of hiPSC-CMs in vitro. Nanotopographies were designed to have a biomimetic interface, based on observations of the oriented myocardial extracellular matrix (ECM) fibers found in vivo. Nanotopographic substrates were integrated with a self-assembling chimeric peptide containing the Arg-Gly-Asp (RGD) cell adhesion motif. Using this platform, cell adhesion to peptide-coated substrates was found to be comparable to that of conventional fibronectin-coated surfaces. Cardiomyocyte organization and structural development were found to be dependent on the nanotopographical feature size in a biphasic manner, with improved development achieved on grooves in the 700–1000 nm range. These findings highlight the capability of surface-functionalized, bioinspired substrates to influence cardiomyocyte development, and the capacity for such platforms to serve as a versatile assay for investigating the role of topographical guidance cues on cell behavior. Such substrates could potentially create more physiologically relevant in vitro cardiac tissues for future drug screening and disease modeling studies

Seasonal dynamics of the depth and rate of anaerobic oxidation of methane in Aarhus Bay (Denmark) sediments

A reactive-transport model has been applied to investigate the dynamics of the sulfate-methane transition zone (SMTZ) in nearshore sediments of Aarhus Bay (Denmark). The sediments are influenced by seasonal variations of temperature and particulate organic carbon (POC) deposition flux at the sediment-water interface. Initially, the model was calibrated at steady state using field data collected at two sites (M1 and M5) in December 2004, and included a dynamic gas phase which determines the depth of the SMTZ. Simulations were then performed under transient conditions of heat propagation in the porous medium, which influenced the solubility of gaseous methane, the diffusion of solutes as well as the kinetic and bioenergetic constraints on redox conditions in the system. Results revealed important variations in local rates of anaerobic oxidation of methane (AOM) over a seasonal cycle due to temperature variation. Seasonal perturbations in POC depositional flux had no influence on AOM rates but did have a strong bearing on sulfate reduction rates in the surface layers of the simulations at both stations. At M5, where the SMTZ was located 63 cm below the sediment-water interface, depth integrated AOM rates varied between 76 and 178 nmol cm-2 d-1. At M1, where the deeper SMTZ (221 cm) experienced less thermal variation, AOM rates varied relatively less (20 to 24 nmol cm-2 d-1). Furthermore, local and depth-integrated AOM rates over the year did not show a simple response to bottom water temperature but exhibited a hysteresis-type behavior related to time lags in solute transport and heat propagation. Overall, the solute concentration profiles were not very sensitive to the seasonal variability in rates or gas transport and the modeled vertical displacement of the SMTZ was limited to <1 cm at M1 and 2–3 cm at M5. The results suggest that the significantly larger apparent displacement observed in the field from repeated coring (80 cm and 16 cm at M1 and M5, respectively) must be attributed to other factors, of which spatial heterogeneity in gas transport rate appears to be the most likely

Mutations in components of complement influence the outcome of Factor I-associated atypical hemolytic uremic syndrome

Genetic studies have shown that mutations of complement inhibitors such as membrane cofactor protein, Factors H, I, or B and C3 predispose patients to atypical hemolytic uremic syndrome (aHUS). Factor I is a circulating serine protease that inhibits complement by degrading C3b and up to now only a few mutations in the CFI gene have been characterized. In a large cohort of 202 patients with aHUS, we identified 23 patients carrying exonic mutations in CFI. Their overall clinical outcome was unfavorable, as half died or developed end-stage renal disease after their first syndrome episode. Eight patients with CFI mutations carried at least one additional known genetic risk factor for aHUS, such as a mutation in MCP, CFH, C3 or CFB; a compound heterozygous second mutation in CFI; or mutations in both the MCP and CFH genes. Five patients exhibited homozygous deletion of the Factor H-related protein 1 (CFHR-1) gene. Ten patients with aHUS had one mutation in their CFI gene (Factor I-aHUS), resulting in a quantitative or functional Factor I deficiency. Patients with a complete deletion of the CFHR-1 gene had a significantly higher risk of a bad prognosis compared with those with one Factor I mutation as their unique vulnerability feature. Our results emphasize the necessity of genetic screening for all susceptibility factors in patients with aHUS