Copula-based agricultural conditional value-at-risk modelling for geographical diversifications in wheat farming portfolio management

An agricultural producer's crop yield and subsequent farming revenues are affected by many complex factors, including price fluctuations, government policy and climate (e.g., rainfall and temperature) extremes. Geographical diversification is identified as a potential farmer adaptation and decision support tool that could assist producers to reduce unfavourable financial impacts due to variabilities in crop price and yield, associated with climate variations. There has been limited research performed on the effectiveness of this strategy. The paper proposed a new statistical approach to investigate whether the geographical spread of wheat farm portfolios across three climate broad-acre (i.e., rain-fed) zones could potentially reduce financial risks for producers in Australian agro-ecological zones. A suite of popular and statistically robust tools applied in finance based on well-established statistical theories, comprised of the Conditional Value-at-Risk (CVaR) and the joint copula model were employed to evaluate the effectiveness geographical diversification. CVaR is utilised to benchmark the loss (i.e., downside risk), while the copula function is employed to model joint distribution among marginal returns (i.e., profit in each zone). The mean-CVaR optimisations indicate that geographical diversification could be a feasible agricultural risk management approach for wheat farm portfolio managers in achieving their optimised expected returns while controlling the risks (i.e., targeting levels of risk). Further, in this study, the copula-based mean-CVaR model is seen to better simulate extreme losses compared to the conventional multivariate-normal models, which underestimate the minimum risk levels at a given target of expected return. Among the suite of tested copula-based models, the vine copula in this study is found to be a superior in capturing the tail dependencies compared to the other multivariate copula models investigated

Transient Mathematical Modeling for Liquid Rocket Engine Systems: Methods, Capabilities, and Experience

The subject of mathematical modeling of the transient operation of liquid rocket engines is presented in overview form from the perspective of engineers working at the NASA Marshall Space Flight Center. The necessity of creating and utilizing accurate mathematical models as part of liquid rocket engine development process has become well established and is likely to increase in importance in the future. The issues of design considerations for transient operation, development testing, and failure scenario simulation are discussed. An overview of the derivation of the basic governing equations is presented along with a discussion of computational and numerical issues associated with the implementation of these equations in computer codes. Also, work in the field of generating usable fluid property tables is presented along with an overview of efforts to be undertaken in the future to improve the tools use for the mathematical modeling process

SCFSlimb Ubiquitin Ligase Suppresses Condensin II–Mediated Nuclear Reorganization by Degrading Cap-H2

Condensin complexes play vital roles in chromosome condensation during mitosis and meiosis. Condensin II uniquely localizes to chromatin throughout the cell cycle and, in addition to its mitotic duties, modulates chromosome organization and gene expression during interphase. Mitotic condensin activity is regulated by phosphorylation, but mechanisms that regulate condensin II during interphase are unclear. Here, we report that condensin II is inactivated when its subunit Cap-H2 is targeted for degradation by the SCF(Slimb) ubiquitin ligase complex and that disruption of this process dramatically changed interphase chromatin organization. Inhibition of SCF(Slimb) function reorganized interphase chromosomes into dense, compact domains and disrupted homologue pairing in both cultured Drosophila cells and in vivo, but these effects were rescued by condensin II inactivation. Furthermore, Cap-H2 stabilization distorted nuclear envelopes and dispersed Cid/CENP-A on interphase chromosomes. Therefore, SCF(Slimb)-mediated down-regulation of condensin II is required to maintain proper organization and morphology of the interphase nucleus

Experimental quantum tossing of a single coin

The cryptographic protocol of coin tossing consists of two parties, Alice and Bob, that do not trust each other, but want to generate a random bit. If the parties use a classical communication channel and have unlimited computational resources, one of them can always cheat perfectly. Here we analyze in detail how the performance of a quantum coin tossing experiment should be compared to classical protocols, taking into account the inevitable experimental imperfections. We then report an all-optical fiber experiment in which a single coin is tossed whose randomness is higher than achievable by any classical protocol and present some easily realisable cheating strategies by Alice and Bob.Comment: 13 page

Oct4 Is Crucial for Transdifferentiation of Hepatocytes to Biliary Epithelial Cells in an in Vitro Organoid Culture Model

BACKGROUND: Hepatocyte to biliary transdifferentiation has been documented in various models of bile duct injury. In this process, mature hepatocytes transform into mature biliary epithelial cells by acquiring biliary phenotypic markers. Several signaling pathways including PI3 kinase, Notch, Hes1, Sox9, and Hippo are shown to be involved in the process. However, if Oct4 is involved in hepatocyte to biliary transdifferentiation is unknown. METHODS: We investigated the role of Oct4 in hepatocyte to biliary transdifferentiation utilizing an in vitro organoid culture system as a model of transdifferentiation. Oct4 was inhibited using adenovirus containing Oct4 shRNA. Hepatocyte specific HNF-4α and biliary specific HNF-1β & CK19 expression were assessed to gauge the extent of transdifferentiation. RESULTS: Oct4 was induced during hepatocyte to biliary transdifferentiation. Oct4 inhibition significantly downregulated the appearance of biliary cells from hepatocytes. This was accompanied by a significant downregulation of signaling pathways including Notch, Sox9, and Hippo. CONCLUSION: Our findings suggest that Oct4 is crucial for hepatocyte to biliary transdifferentiation and maturation and that it acts upstream of Notch, Sox9, and Hippo signaling in this model. This finding identifies new signaling through Oct4 in plasticity between hepatocytes and biliary epithelial cells, which can be potentially utilized to identify new strategies in chronic biliary diseases

Molecular differentiation of the Murraya paniculata Complex (Rutaceae: Aurantioideae: Aurantieae)

Background: Orange jasmine has a complex nomenclatural history and is now known as Murraya paniculata (L.) Jack. Our interest in this common ornamental stemmed from the need to resolve its identity and the identities of closely related taxa as hosts of the pathogen 'Candidatus Liberibacter asiaticus' and its vector Diaphorina citri. Understanding these microbe-vector-plant relationships has been hampered by taxonomic confusion surrounding Murraya at both the generic and specific levels. Results: To resolve the taxonomic uncertainty, six regions of the maternally-inherited chloroplastal genome and part of the nuclear-encoded ITS region were amplified from 85 accessions of Murraya and Merrillia using the polymerase chain reaction (PCR). Clustering used maximum parsimony (MP), maximum likelihood (ML) and Bayesian inference (BI). Chronograms were produced for molecular dating, and to test the monophyly of Murraya rigorously, using selected accessions of Murraya and 26 accessions of the Rutaceae and Simarubaceae. Sequence data from the ITS and chloroplastal regions suggest that Murraya paniculata (sensu (Swingle WT and Reece CR, The Citrus Industry, p. 190-430, 1967)) can be separated into four distinct but morphologically somewhat cryptic taxa: Murraya paniculata (sensu (Mabberley DJ, Taxon 65:366-371, 2016)), M. elongata, M. sumatrana and M. lucida. In addition, Murraya omphalocarpa was identified as a putative hybrid of M. paniculata and M. lucida with two geographically isolated nothovarieties representing reciprocal crosses. Murraya is monophyletic, and molecular dating suggests that it diverged from Merrillia during the Miocene (23-5 Ma) with this Murraya group speciating and dispersing during the Middle Miocene onwards. Conclusions: The accessions from Asia and Australasia used in this study grouped into biogeographical regions that match herbarium specimen records for the taxa that suggest natural allopatric distributions with limited overlap and hybridity. Murraya paniculata has been distributed around the world as an ornamental plant. The division of the Murraya paniculata complex into four species with a rare hybrid also confirms morphological studies