1,716 research outputs found
Roll-Up & Cross-Collateralization in DIP (Debtor-In-Possession) Financing as Measures of Creditor Control
There is an increasing debate on whether creditors exert excessive power and influence through their DIP (Debtor-in-Possession) lending arrangements in the Chapter 11 bankruptcy process. DIP lenders often advance the priority of their prepetition claims as a reward for extending credit (through DIP financing) through roll-up or cross-collateralization provisions. As these provisions violate the general principle of equitable treatment among the same class in bankruptcy, they are viewed as products of excessive creditor control. Hence, the paper compares U.S. bankruptcy cases from 2009 to 2011 with roll-up or cross-collateralization provisions in their DIP arrangements to those without, focusing on the CEO turnover rate and the strictness of covenants as signals of creditor control. As companies with those provisions report higher CEO turnover rates and stricter covenants, it is concluded that DIP agreements with cross-collateralization or roll-up signal greater creditor control than those without
Discovery Of Ethanol-Responsive Small Rnas In Zymomonas Mobilis
Zymomonas mobilis is a bacterium that can produce ethanol by fermentation. Due to its unique metabolism and efficient ethanol production, Z. mobilis has attracted special interest for biofuel energy applications; an important area of study is the regulation of those specific metabolic pathways. Small RNAs (sRNAs) have been studied as molecules that function as transcriptional regulators in response to cellular stresses. While sRNAs have been discovered in various organisms by computational prediction and experimental approaches, their discovery in Z. mobilis has not yet been reported. In this study, we have applied transcriptome analysis and computational predictions to facilitate identification and validation of 15 novel sRNAs in Z. mobilis. We furthermore characterized their expression in the context of high and low levels of intracellular ethanol. Here, we report that 3 of the sRNAs (Zms2, Zms4, and Zms6) are differentially expressed under aerobic and anaerobic conditions, when low and high ethanol productions are observed, respectively. Importantly, when we tested the effect of ethanol stress on the expression of sRNAs in Z. mobilis, Zms2, Zms6, and Zms18 showed differential expression under 5% ethanol stress conditions. These data suggest that in this organism regulatory RNAs can be associated with metabolic functions involved in ethanol stress responses.NSF CBET-1254754Welch Foundation F-1756Cellular and Molecular BiologyChemical Engineerin
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Exploring novel regulatory noncoding RNAs associated with ethanol tolerance in Zymomonas mobilis for strain engineering
Zymomonas mobilis has been identified as a promising cellular factory for biofuels due to its efficient, natural production of and tolerance to ethanol. With rising demands of efficiency and sustainability, the use of microbes as chemical factories is increasingly attractive. In bacteria, small noncoding RNAs have been highlighted as powerful tools due to their regulatory roles in cellular pathways and as such are being increasingly exploited for engineering purposes. As global controllers of gene expression, noncoding regulatory RNAs represent powerful tools for engineering complex phenotypes. However, mechanistic analysis of these regulators in bacteria lags far behind their high-throughput search and discovery; this makes it difficult to understand how to efficiently identify noncoding RNAs that could be used to engineer a phenotype of interest. This dissertation describes discovery of novel global regulatory small noncoding RNAs that impact ethanol tolerance in Z. mobilis using a forward systems approach. The effect of the bioinformatically predicted candidates were experimentally characterized by building overexpression and deletion strains. This led to the successful uncovering of several sRNAs that could be manipulated to enhance ethanol tolerance as well as ethanol production in Z. mobilis. Using these ethanol-related sRNAs, we then performed traditional genetic and biochemical approaches as well as transcriptomics and proteomics methods to identify a pool of mRNA targets and pathways that were being regulated by these sRNAs under conditions of enhanced ethanol tolerance. Additionally, control elements (especially untranslated regions (UTRs)) that regulate gene expression at the local level associated with ethanol as well as other metabolic stresses in Z. mobilis were searched and exploited. Specifically, ethanol responsive-UTR element identified in this work regulates the expression of Hfq and affects cell growth under ethanol stress condition. This work represents the first application of a de novo sRNA engineering strategy in a non-model organism, Z. mobilis, which is of relevance to biofuel technologies. Furthermore, our development and application of a novel bioinformatics pipeline for this work has demonstrated the ability to use formal computational approaches (in conjuction with systems-level methods) to accelerate the discovery of specific pathways that could be further optimized to enhance a given complex phenotypeCellular and Molecular Biolog
RTNH+: Enhanced 4D Radar Object Detection Network using Combined CFAR-based Two-level Preprocessing and Vertical Encoding
Four-dimensional (4D) Radar is a useful sensor for 3D object detection and
the relative radial speed estimation of surrounding objects under various
weather conditions. However, since Radar measurements are corrupted with
invalid components such as noise, interference, and clutter, it is necessary to
employ a preprocessing algorithm before the 3D object detection with neural
networks. In this paper, we propose RTNH+ that is an enhanced version of RTNH,
a 4D Radar object detection network, by two novel algorithms. The first
algorithm is the combined constant false alarm rate (CFAR)-based two-level
preprocessing (CCTP) algorithm that generates two filtered measurements of
different characteristics using the same 4D Radar measurements, which can
enrich the information of the input to the 4D Radar object detection network.
The second is the vertical encoding (VE) algorithm that effectively encodes
vertical features of the road objects from the CCTP outputs. We provide details
of the RTNH+, and demonstrate that RTNH+ achieves significant performance
improvement of 10.14\% in and 16.12\% in
over RTNH.Comment: Arxiv preprin
Effects of Forestland Ownership Conversion on Greenhouse Gas Emissions: The Case of South Korea
This research analyzed the effects of forestland conversion from private to public ownership on greenhouse gas emissions by quantifying the relationship between forestland ownership conversion and deforestation, and then examining the effects of the change in deforestation on greenhouse gas emissions in South Korea. Ex ante simulations forecast greenhouse gas emissions resulting from deforestation rates under the current level of national forestland and three scenarios of increased percentages of national forestland. The findings suggest that increasing the percentage of national forestland would mitigate the increase in the deforestation rate, which in turn would moderate the increase in greenhouse gas emissions.greenhouse gas emissions, Forestland Ownership, Environmental Economics and Policy, Q15, Q23, Q24, Q54,
Estimating Live Fuel Moisture in Southern California Using Remote Sensing Vegetation Water Content Proxies
Wildfires are a major ecological disturbance in Southern California and often lead to great destruction along the Wildland-Urban Interface. Live fuel moisture has been used as an important indicator of wildfire risk in measurements of vegetation water content. However, the limited field measurements of live fuel moisture in both time and space have affected the accuracy of wildfire risk estimations. Traditional estimation of live fuel moisture using remote sensing data was based on vegetation indices, indirect proxies of vegetation water content and subject to influence from weather conditions. In this study, we investigated the feasibility of estimating live fuel moisture using vegetation indices, Soil Moisture Active Passive L-band soil moisture data and the modeled vegetation water content using a non-linear model based on VIs and the stem factor associated with remote sensing moisture data products. The stem factor describes the peak amount of water residing in stems of plants and varies by land cover. We also compared the outcomes from regression models and recurrent neural network using the same independent variables. We found the modeled vegetation water content outperformed vegetation indices and the L-band soil moisture observations, suggesting a non-linear relationship between live fuel moisture and the remotely sensed vegetation signatures. We discuss our results which will improve the predictability of live fuel moisture
Application of the assumed mode method to the vibration analysis of rectangular plate structures in contact with fluid
Micro-nano hybrid structures with manipulated wettability using a two-step silicon etching on a large area
Nanoscale surface manipulation technique to control the surface roughness and the wettability is a challenging field for performance enhancement in boiling heat transfer. In this study, micro-nano hybrid structures (MNHS) with hierarchical geometries that lead to maximizing of surface area, roughness, and wettability are developed for the boiling applications. MNHS structures consist of micropillars or microcavities along with nanowires having the length to diameter ratio of about 100:1. MNHS is fabricated by a two-step silicon etching process, which are dry etching for micropattern and electroless silicon wet etching for nanowire synthesis. The fabrication process is readily capable of producing MNHS covering a wafer-scale area. By controlling the removal of polymeric passivation layers deposited during silicon dry etching (Bosch process), we can control the geometries for the hierarchical structure with or without the thin hydrophobic barriers that affect surface wettability. MNHS without sidewalls exhibit superhydrophilic behavior with a contact angle under 10°, whereas those with sidewalls preserved by the passivation layer display more hydrophobic characteristics with a contact angle near 60°
Generation of a single-cycle pulse using a two-stage compressor and its temporal characterization using a tunnelling ionization method
A single-cycle laser pulse was generated using a two-stage compressor and characterized using a pulse characterization technique based on tunnelling ionization. A 25-fs, 800-nm laser pulse was compressed to 5.5 fs using a gas-filled hollow-core fibre and a set of chirped mirrors. The laser pulse was further compressed, down to the single-cycle limit by propagation through multiple fused-silica plates and another set of chirped mirrors. The two-stage compressor mitigates the development of higher-order dispersion during spectral broadening. Thus, a single-cycle pulse was generated by compensating the second-order dispersion using chirped mirrors. The duration of the single-cycle pulse was 2.5 fs, while its transform-limited duration was 2.2 fs. A continuum extreme ultraviolet spectrum was obtained through high-harmonic generation without applying any temporal gating technique. The continuum spectrum was shown to have a strong dependence on the carrier-envelope phase of the laser pulse, confirming the generation of a single-cycle pulse. © 2019, The Author(s
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