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Small genes (40,000 small-gene families in ∼2.3 million phage genome contigs. We find that small genes in phage genomes are approximately 3-fold more prevalent than in host prokaryotic genomes. Our approach enriches for small genes that are translated in microbiomes, suggesting the small genes identified are coding. More than 9,000 families encode potentially secreted or transmembrane proteins, more than 5,000 families encode predicted anti-CRISPR proteins, and more than 500 families encode predicted antimicrobial proteins. By combining homology and genomic-neighborhood analyses, we reveal substantial novelty and diversity within phage biology, including small phage genes found in multiple host phyla, small genes encoding proteins that play essential roles in host infection, and small genes that share genomic neighborhoods and whose encoded proteins may share related functions.

Colloid transport through complex and dynamic (i.e. non-steady-state) hydrologic systems is rarely studied, owing to the difficulty of constraining initial and boundary conditions and quantifying colloid-porous media and colloid-colloid interactions in transient flow systems. Here we present a particle tracer experiment conducted on a sloped lysimeter receiving periodic rainfall events for 10 days. Four unique, DNA-labelled particle tracers were injected both in sequence and in parallel, together with a conservative tracer (deuterium), over the course of the first day and allowed to move through the system. Discharge-particle tracer concentration curves and the spatial distribution of particle tracer mass retained in the soil at the end of the experiment were found to be highly dependent on the timing of the tracer injection and the precipitation input and subsequent dynamic response of the water table. Overall, neglecting the total DLT recovery rate, the DLT particle tracer breakthrough trend (DNA-labelled particle tracer 4) was similar to deuterium and decreased over time with the exception of a few peaks later in the experiment. The individual particle tracer breakthrough curves suggest a complex system with different fast transport mechanisms (e.g. capillary barrier and size exclusion effect) and slow retention-release mechanisms (e.g. straining, physical-chemical adsorption), which resulted in particle tracers transferring faster than deuterium in the first 10 h of the experiment but being exceeded by deuterium soon after deuterium started to break through. The experiment not only highlights the interaction of repeated colloidal pollution events in hydrologic systems with different pre-event saturation conditions, but also the benefits of using multiple synchronous or sequential tracer applications to dissect explicit formulations of water flow and colloid transport processes in complex and dynamic hydrological systems. Such explicit process formulations could help improve understanding hydrologically-controlled transport through catchments and the quantitative prediction of these processes with water quality models.

Differentiating the contributions of photosynthesis and respiration to the global carbon cycle is critical for improving predictive climate models. Carbonic anhydrase (CA) activity in leaves is responsible for the largest biosphere-atmosphere trace gas fluxes of carbonyl sulfide (COS) and the oxygen-18 isotopologue of carbon dioxide (CO18O) that both reflect gross photosynthetic rates. However, CA activity also occurs in soils and will be a source of uncertainty in the use of COS and CO18O as carbon cycle tracers until process-based constraints are improved. In this study, we measured COS and CO18O exchange rates and estimated the corresponding CA activity in soils from a range of biomes and land use types. Soil CA activity was not uniform for COS and CO2, and patterns of divergence were related to microbial community composition and CA gene expression patterns. In some cases, the same microbial taxa and CA classes catalyzed both COS and CO2 reactions in soil, but in other cases the specificity towards the two substrates differed markedly. CA activity for COS was related to fungal taxa and β-D-CA expression, whereas CA activity for CO2 was related to algal and bacterial taxa and α-CA expression. This study integrates gas exchange measurements, enzyme activity models, and characterization of soil taxonomic and genetic diversity to build connections between CA activity and the soil microbiome. Importantly, our results identify kinetic parameters to represent soil CA activity during application of COS and CO18O as carbon cycle tracers.

In markets where differences in the environmental performance of competing firms arise due to differences in technology that cannot be altered in the short run and firms have private information about their own current technology, I show that market competition creates a strategic disincentive for adopting ecolabels (even if the cost of adoption is negligible) to directly and credibly communicate this private information to environmentally conscious consumers. Firms adopt ecolabels only if the green premium that buyers are willing to pay is large relative to the production cost advantage of dirty firms; ecolabels reduce market power, increase the market share of clean firms, and reduce expected environmental damage. I analyze firms' strategic (long‐run) incentive to invest in the development of clean technology where the outcome of such investment is uncertain. The availability of an ecolabel to directly communicate private information about the final outcome of such an investment enhances the expected net surplus whereas it reduces the ex ante strategic incentive to invest which in turn lowers industry investment in cleaner technology, relative to the case with no ecolabels. [ABSTRACT FROM AUTHOR]

The present study focuses on the numerical modeling of the co-combustion of reject coal (RC) and sal leaves (SL) in a drop tube furnace (DTF) under different conditions, including air-fuel and oxy-fuel environments. The numerical results highlight the significant influence of replacing the N2 atmosphere with CO2 on the temperature profiles of individual fuels and their blends. For instance, when exposed to a 21%O2/79%CO2 atmosphere, Blend SL3 and Blend SL5 experience a decrease in temperature from 1372 K to 1559 K to 1327 K and 1395 K, respectively. Conversely, increasing the O2 concentration to 35% leads to a temperature rise. Furthermore, the combustion analysis reveals that the addition of 10% SL to RC in a 21%O2/79%N2 environment enhances the devolatilization rate from 1.41 × 10−12 kg/s to 1.77 × 10−12 kg/s. Additionally, the char combustion process for all blends is completed closer to the DTF inlet at 0.28 m, compared to 0.32 m for RC alone. These findings indicate that blending SL with RC promotes a favorable combustion process. Moreover, increasing the O2 concentration to 35% in oxy-fuel conditions enhances the temperature profiles. The numerical analysis demonstrates good agreement with experimental data within a range of ±5%–11%. This suggests that the developed model can be effectively utilized for optimizing and designing biomass co-firing systems in industrial applications, considering both air-fuel and oxy-fuel conditions. [ABSTRACT FROM AUTHOR]

Undergraduate institutions serve as stepping stones to students' careers. Teaching and learning in science classrooms require quality and integrated teaching–research learning experiences that prepare students to advance their careers. Using publicly available data sets and open-access data analyses software can be impactful for engaging students in meaningful research experiences while keeping institutional expenses associated with implementing and supporting research opportunities low. In this article, we share two examples of student-led data research that utilized open data and software to analyze microbial sequence data. As part of this process, we also recognized the need for discipline-specific databases that can hold a record of publicly available data. Such a setup will support undergraduate educators and students in accessing data relevant to their requirements, thereby narrowing the gap between data availability and accessibility. Finally, both examples illustrate the benefits of using open resources in supporting student learning, with the possibility of using such resources to develop course-based undergraduate research experiences as part of course curricula. [ABSTRACT FROM AUTHOR]

A series of implicit large eddy simulations have been conducted to implement thermal control on the transonic shock-boundary layer interactions (SBLIs) over a natural laminar flow airfoil, operating beyond the drag divergence Mach number. The study focuses on the SHM1 airfoil, where the baseline flow exhibits shock-induced separation under specific conditions: free stream Mach number M ∞ = 0.78 , angle of attack α = 0.38 ° , and Reynolds number R e = 8 × 10 6 . A time-periodic surface heat flux is introduced, strategically located near the shock structures of the unaltered flow, and the impact of heating vs cooling is investigated through instantaneous Schlieren visualizations and vorticity dynamics, and time-averaged load distributions and boundary layer parameters. Time-averaged Mach contours are utilized to measure the shock strength and extent, revealing that thermal control effectively mitigates the detrimental impact of transonic SBLI on the airfoil's performance. Cooling control emerges as the more effective method, and a case featuring multiple cooling controls near the shock structures demonstrates superior efficacy in controlling shock waves and suppressing shock-induced separation. This optimized configuration results in an improved aerodynamic efficiency of 12.65% compared to the baseline flow. [ABSTRACT FROM AUTHOR]

The separation-induced transition on the suction surface of a T106A low pressure turbine blade is a complex phenomenon with implications for aerodynamic performance. In this numerical investigation, we explore an adverse pressure gradient-dominated flow subjected to varying levels of free stream excitation, as the underlying separation-induced transition is a critical factor in assessing blade profile loss. By comprehensively analyzing the effects of free stream turbulence (FST) on the transition process, we delve into the various mechanisms which govern the instabilities underlying bypass transition by studying the instantaneous enstrophy field. This involves solving the two-dimensional (2D) compressible Navier–Stokes equation through a series of numerical simulations, comparing a baseline flow to cases where FST with varying turbulent intensity (T u = 4 % and 7%) is imposed at the inflow. Consistent with previous studies, the introduction of FST is observed to delay flow separation and trigger early transition. We explore the different stages of bypass transition, from the initial growth of disturbances (described by linear stability theory) to the emergence of unsteady separation bubbles that merge into turbulent spots (due to nonlinear interactions), by examining the vorticity dynamics. Utilizing the compressible enstrophy transport equation for the flow in a T106A blade passage, we highlight the various routes of bypass transition resulting from different levels of FST, emphasizing the relative contributions from baroclinicity, compressibility, and viscous terms. [ABSTRACT FROM AUTHOR]

The present study performs three-dimensional (3D) numerical simulations of coal combustion of four samples with varying ash content in a drop tube furnace (DTF) to mimic the particle heating rates observed in industrial furnaces. The numerical framework adopted is validated with prior experimental and simulation results using a 3D cylindrical geometry and a very good match is obtained for the axial temperature distribution and particle burnout rate. The combustion performance of coal samples with varying ash contents of 2.3, 16.6, 24.1, and 37.2 wt%, is explored through temperature profiles, burnout rates, particle tracking, and mass fractions of various products of combustion. A user-defined function is used to specify the 14 species, 10-step solid particle combustion with a modified eddy dissipation concept model for volatile combustion. The range of ash content considered is for Indian coal which has a high degree of heterogeneity, making the evaluation of its combustion performance, a challenge. The present work aims to provide benchmark set of results showing the evolution of the evaporated, charred, and volatile mass for the three ash contents, which has not been attempted before. It is found that the high-ash content Indian coal samples have a tendency to produce less NOx . A 9:52% reduction in the NOx is obtained for the coal sample with 37:2% ash compared to that with 16:6% ash. The results suggest that the combustion performance is enhanced when the ash content falls within an optimum range of 20 35%. [ABSTRACT FROM AUTHOR]