The herbicide atrazine is used extensively throughout the United States, and is a widespread groundwater and surface water contaminant. Biochar has been shown to strongly sorb organic compounds and ...could be used to reduce atrazine leaching. We used lab and field experiments to determine biochar impacts on atrazine leaching under increasingly heterogeneous soil conditions. Application of pine chip biochar (commercially pyrolyzed between 300 and 550 °C) reduced cumulative atrazine leaching by 52% in homogenized (packed) soil columns (p=0.0298). Biochar additions in undisturbed soil columns did not significantly (p>0.05) reduce atrazine leaching. Mean peak groundwater atrazine concentrations were 53% lower in a field experiment after additions of 10 t ha(-1) acidified biochar (p=0.0056) relative to no biochar additions. Equivalent peat applications by dry mass had no effect on atrazine leaching. Plots receiving a peat-biochar mixture showed no reduction, suggesting that the peat organic matter may compete with atrazine for biochar sorption sites. Several individual measurement values outside the 99% confidence interval in perched groundwater concentrations indicate that macropore structure could contribute to rare, large leaching events that are not effectively reduced by biochar. We conclude that biochar application has the potential to decrease peak atrazine leaching, but heterogeneous soil conditions, especially preferential flow paths, may reduce this impact. Long-term atrazine leaching reductions are also uncertain.
The effect of long-term versus short-term water content on soil organic carbon (SOC) mineralizability was evaluated in a six-week incubation trial. Soils were sampled from field sites in upstate New ...York used for rain-fed bioenergy crop production: nitrogen (N)- fertilized reed canarygrass, switchgrass, switchgrass + N, as well as a broadleaf-grass fallow. Within each cropping system, natural moisture gradients due to topography and subsoil structure allowed us to sample across regions with high (0.5 g g−1), mid (0.4 g g−1) and low (0.3 g g−1) water content. Moisture of the laboratory incubations was adjusted mimicking the three average field moisture levels in a full factorial design. Increasing laboratory moisture in the incubations increased cumulative carbon mineralization per unit soil (C mineralization) and cumulative C mineralization per unit SOC (C mineralizability) (main effect p < 0.0001), indicating that lower average moisture as found at this site on average limited mineralization but higher average moisture did not. C mineralizability at high field moisture was 31% (25-42%) lower than at low field moisture across all cropping systems, regardless of moisture adjustment in the incubation. The mean slow C pool size of soils from high field moisture sites (997.1 ± 0.1 mg C g−1 C) was 0.2% greater than that of soils from low field moisture sites (p < 0.0001), obtained by fitting a double-exponential model. The mean residence time of the slow mineralizing C pool for soils from low field moisture sites was 5.5 ± 0.1 years, in comparison to 8.0 ± 0.1 years for soils from high field moisture sites (p < 0.0001). While permanganate-oxidizable carbon (POXC) per unit SOC (r = 0.1) was positively correlated to C mineralizability, wet aggregate stability (r = −0.2) was negatively correlated to C mineralizability. Above-ground biomass did not affect C mineralizability (p > 0.05) and root biomass marginally influenced (p = 0.05) C mineralizability after correcting for soil texture variations. Additionally, after correcting for soil texture variations and biomass inputs, C mineralizability significantly decreased with higher field moisture (p = 0.02), indicating possible stabilization mechanisms through mineral interactions of SOC under high water content. Bulk contents of pedogenic iron and aluminum determined by oxalate extraction did not clearly explain differences in mineralizability. However, exchangeable calcium and magnesium contents were significantly (p < 0.0001) greater in high moisture soils than soils with lower moisture. Additionally, cumulative C mineralizability at 6 weeks was negatively correlated to calcium (r = −0.7) and magnesium (r = −0.6) and mean residence time of the modeled slow pool correlated positively with calcium (r = 0.4). Therefore, cation bridging by retained or illuviated base ions was more important than redox changes of iron as a stabilization mechanism in this experiment.
•Soil organic carbon (SOC) was highest in bioenergy plantations under high moisture.•SOC mineralizability was 25–42% lower from high field moisture compared to low field moisture.•Mineralization increased with higher moisture in laboratory incubation.•Above-ground biomass or root biomass did not affect C mineralizability.•Aggregate stability was negatively correlated to C mineralizability.•Base cation contents negatively correlated with mineralizability.
The present paper represents the second contribution in the Genera of Fungi series, linking type species of fungal genera to their morphology and DNA sequence data, and where possible, ecology. This ...paper focuses on 12 genera of microfungi, 11 of which the type species are neo- or epitypified here: Allantophomopsis (A. cytisporea, Phacidiaceae, Phacidiales, Leotiomycetes), Latorua gen. nov. (Latorua caligans, Latoruaceae, Pleosporales, Dothideomycetes), Macrodiplodiopsis (M. desmazieri, Macrodiplodiopsidaceae, Pleosporales, Dothideomycetes), Macrohilum (M. eucalypti, Macrohilaceae, Diaporthales, Sordariomycetes), Milospium (M. graphideorum, incertae sedis, Pezizomycotina), Protostegia (P. eucleae, Mycosphaerellaceae, Capnodiales, Dothideomycetes), Pyricularia (P. grisea, Pyriculariaceae, Magnaporthales, Sordariomycetes), Robillarda (R. sessilis, Robillardaceae, Xylariales, Sordariomycetes), Rutola (R. graminis, incertae sedis, Pleosporales, Dothideomycetes), Septoriella (S. phragmitis, Phaeosphaeriaceae, Pleosporales, Dothideomycetes), Torula (T. herbarum, Torulaceae, Pleosporales, Dothideomycetes) and Wojnowicia (syn. of Septoriella, S. hirta, Phaeosphaeriaceae, Pleosporales, Dothideomycetes). Novel species include Latorua grootfonteinensis, Robillarda africana, R. roystoneae, R. terrae, Torula ficus, T. hollandica, and T. masonii spp. nov., and three new families: Macrodiplodiopsisceae, Macrohilaceae, and Robillardaceae. Authors interested in contributing accounts of individual genera to larger multi-authored papers to be published in IMA Fungus, should contact the associate editors listed for the major groups of fungi on the List of Protected Generic Names for Fungi (www.generaoffungi.org).
Metabolic fluxes may be regulated "hierarchically," e.g., by changes of gene expression that adjust enzyme capacities (Vmax) and/or "metabolically" by interactions of enzymes with substrates, ...products, or allosteric effectors. In the present study, a method is developed to dissect the hierarchical regulation into contributions by transcription, translation, protein degradation, and posttranslational modification. The method was applied to the regulation of fluxes through individual glycolytic enzymes when the yeast Saccharomyces cerevisiae was confronted with the absence of oxygen and the presence of benzoic acid depleting its ATP. Metabolic regulation largely contributed to the almost equal to10-fold change in flux through the glycolytic enzymes. This contribution varied from 50 to 80%, depending on the glycolytic step and the cultivation condition tested. Within the 50-20% hierarchical regulation of fluxes, transcription played a minor role, whereas regulation of protein synthesis or degradation was the most important. These also contributed to 75-100% of the regulation of protein levels.
Article 59.1, of the International Code of Nomenclature for Algae, Fungi, and Plants (ICN; Melbourne Code), which addresses the nomenclature of pleomorphic fungi, became effective from 30 July 2011. ...Since that date, each fungal species can have one nomenclaturally correct name in a particular classification. All other previously used names for this species will be considered as synonyms. The older generic epithet takes priority over the younger name. Any widely used younger names proposed for use, must comply with Art. 57.2 and their usage should be approved by the Nomenclature Committee for Fungi (NCF). In this paper, we list all genera currently accepted by us in
Dothideomycetes
(belonging to 23 orders and 110 families), including pleomorphic and non-pleomorphic genera. In the case of pleomorphic genera, we follow the rulings of the current ICN and propose single generic names for future usage. The taxonomic placements of 1261 genera are listed as an outline. Protected names and suppressed names for 34 pleomorphic genera are listed separately. Notes and justifications are provided for possible proposed names after the list of genera. Notes are also provided on recent advances in our understanding of asexual and sexual morph linkages in
Dothideomycetes
. A phylogenetic tree based on four gene analyses supported 23 orders and 75 families, while 35 families still lack molecular data.
Si1−xGex is a key material in modern complementary metal‐oxide‐semiconductor and bipolar devices. However, despite considerable efforts in metal‐silicide and ‐germanide compound material systems, ...reliability concerns have so far hindered the implementation of metal‐Si1−xGex junctions that are vital for diverse emerging “More than Moore” and quantum computing paradigms. In this respect, the systematic structural and electronic properties of Al‐Si1−xGex heterostructures, obtained from a thermally induced exchange between ultra‐thin Si1−xGex nanosheets and Al layers are reported. Remarkably, no intermetallic phases are found after the exchange process. Instead, abrupt, flat, and void‐free junctions of high structural quality can be obtained. Interestingly, ultra‐thin interfacial Si layers are formed between the metal and Si1−xGex segments, explaining the morphologic stability. Integrated into omega‐gated Schottky barrier transistors with the channel length being defined by the selective transformation of Si1−xGex into single‐elementary Al leads, a detailed analysis of the transport is conducted. In this respect, a report on a highly versatile platform with Si1−xGex composition‐dependent properties ranging from highly transparent contacts to distinct Schottky barriers is provided. Most notably, the presented abrupt, robust, and reliable metal‐Si1−xGex junctions can open up new device implementations for different types of emerging nanoelectronic, optoelectronic, and quantum devices.
The authors report monolithic and single‐crystal heterostructures with abrupt junctions, obtained from a thermal Al‐Si1−xGex exchange reaction. Integrated into Schottky barrier transistors with single‐elementary Al contacts, Si1−xGex composition‐dependent properties ranging from highly transparent contacts to distinct Schottky barriers are found. The obtained metal‐Si1−xGex heterostructures can be a key building block for emerging nanoelectronic, optoelectronic and quantum devices.
Reconfigurable field‐effect transistors, capable of being dynamically programmed during run‐time, overcome the static nature of conventional complementary metal‐oxide semiconductors by reducing the ...transistor count and the circuit path delay. Thereby, SiGe and Ge are predicted to boost drive currents, switching speed and to reduce power consumption. Nevertheless, Ge‐based reconfigurable field‐effect transistor prototypes have so far fallen short in reaching both the promised performance due to interface instability to their contacts and gate oxides, as well as in reaching the current–voltage symmetry necessary for circuit applicability. Here, a top‐down fabricated SiGe‐based reconfigurable transistor technology is reported that is comprised of a vertical Si‐Si0.67Ge0.33 heterostructure enabling the envisioned high and symmetric on‐currents of both n‐ and p‐type operation. Monolithic integration with single‐elementary crystalline Al contacts alleviates process variability compared to conventional Ni‐silicide/Ni‐germanide contacts and introduces an ultra‐thin Si interlayer providing stability and equal injection efficiency of holes and electrons. The implementation of a three top‐gate transistor in combination with a hysteresis‐free Si/SiO2/HfO2 gate stack enhances polarity control and leakage current suppression to limit static power dissipation. Importantly, the obtained Al‐Si‐SiGe multi‐heterojunction and advanced reconfigurable transistor design is the first Ge‐based technology showing the envisioned stability and performance enhancements.
This work reports on the electronic transport in a SiGe‐based reconfigurable transistor embedded with single‐elementary Al contacts, capable of providing high and symmetric on‐currents for both, n‐ and p‐type operation. This is achieved by a thermally induced SiGe exchange reaction resulting in a high‐quality Al‐Si‐Si0.67Ge0.33 junction with symmetric activation energies for electrons and holes.
Here, we present a Ge based reconfigurable transistor, capable of dynamic run-time switching between n- and p-type operation with enhanced performance compared to state-of-the- art Si devices. ...Thereto, we have monolithically integrated an ultra-thin epitaxial and defect-free Ge layer on a Si on insulator platform. To evade the commonly observed process variability of Ni-germanides, Al-Si-Ge multi-heterojunction contacts have been employed, providing process stability and the required equal injection capabilities for electrons and holes. Integration into a three top-gate transistor enables effective polarity control and efficient leakage current suppression to limit static power dissipation. Exploiting the advantages of multi-gate transistors, combinational wired-AND gates are shown to be capable of extending a single transistor to a logic gate. Notably, the obtained Al-Si-Ge multi-heterojunction reconfigurable transistors constitute the first CMOS compatible platform to combine efficient polarity control enabling the envisioned performance enhancements of Ge based reconfigurable transistors.
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