Forecasting Livestock Feed Cost Risks Using Futures and Options

The costs of corn- and soybean-based feeds compose a substantial proportion of the variable costs faced by both mainstream and emergent confined livestock producers. This research develops a method to provide a joint distribution of prices of corn and soybean meal at a future time. Black's 1976 option model and stochastic volatility jump diffusion (SVJD) model are compared in volatility forecasting performance. In general, SVJD is superior to Black's model, though their performance is both commodity-specific and forecasting horizon specific.Livestock Production/Industries, Marketing,

Empirical Performance of Alternative Option Pricing Models for Commodity Futures Options

The central part of pricing agricultural commodity futures options is to find appropriate stochastic process of the underlying assets. The Black's (1976) futures option pricing model laid the foundation for a new era of futures option valuation theory. The geometric Brownian motion assumption girding the Black's model, however, has been regarded as unrealistic in numerous empirical studies. Option pricing models incorporating discrete jumps and stochastic volatility have been studied extensively in the literature. This study tests the performance of major alternative option pricing models and attempts to find the appropriate model for pricing commodity futures options.Marketing,

Managing Livestock Feed Cost Risks Using Futures and Options

The costs of corn- and soybean-based feeds compose a substantial proportion of the variable costs faced by both mainstream and emergent confined livestock producers. This research develops a method to provide a joint distribution of prices of corn and soybean meal at a future time. Black's 1976 option model and stochastic volatility jump diffusion (SVJD) model are compared in volatility forecasting performance. In general, SVJD is superior to Black's model, though their performance is both commodity-specific and forecasting horizon specific. The price forecast can assist livestock producers to assess different feed procurement strategies in terms of the distribution of costs projected for each strategy.Risk and Uncertainty,

Adaption of Self-Phasing Antenna Systems to Space Missions

The ability of the self-phasing antennas to nor only provide high gain but also to minimize the requirement of satellite attitude control has rendered them very attractive for use in satellite communication systems. The potential advantages and versatility afforded by self-phasing antennas are analyzed in this paper with discussions of results obtained for two specific applications. The paper begins with a description of two types of self-phasing antennas., namely^ the Van Atta array and the so-called phase conjugation array; similarities and differences in operation of the two types of arrays of various geometrical configurations such as planar^ cylindrical^ and spherical^ are then discussed. Problem areas which are common to both types are indicated and techniques such as array scaling and frequency translation which are useful in dealing with some of these problems are also included in the discussion. Examples of two specific applications of self-phasing antennas are used to demonstrate their attractive features. The first involves the use of self-phasing arrays on a communication satellite in a critically inclined elliptic orbit. The second deals with the mutual acquisition problem between two vehicles employing selfphasing antennas for space to space communication. In the latter application^ the finite Markov chain technique, is used to analyze the problem and the results are compared with those of the corresponding problem wherein the satellites employ narrow beam antennas pointing at each other to accomplish acquisition. The acquisition condition which would render a self-phasing system more attractive than a narrow beam system are indicated

Distance measures in gravitational-wave astrophysics and cosmology

We present quantities which characterize the sensitivity of gravitational-wave observatories to sources at cosmological distances. In particular, we introduce and generalize the horizon, range, response, and reach distances. These quantities incorporate a number of important effects, including cosmologically well-defined distances and volumes, cosmological redshift, cosmological time dilation, and rate density evolution. In addition, these quantities incorporate unique aspects of gravitational wave detectors, such as the variable sky sensitivity of the detectors and the scaling of the sensitivity with inverse distance. An online calculator (https://users.rcc.uchicago.edu/~dholz/gwc/) and python notebook (https://github.com/hsinyuc/distancetool) to determine GW distances are available. We provide answers to the question: "How far can gravitational-wave detectors hear?

Large-scale analysis of antisense transcription in wheat using the Affymetrix GeneChip Wheat Genome Array

<p>Abstract</p> <p>Background</p> <p>Natural antisense transcripts (NATs) are transcripts of the opposite DNA strand to the sense-strand either at the same locus (<it>cis</it>-encoded) or a different locus (<it>trans</it>-encoded). They can affect gene expression at multiple stages including transcription, RNA processing and transport, and translation. NATs give rise to sense-antisense transcript pairs and the number of these identified has escalated greatly with the availability of DNA sequencing resources and public databases. Traditionally, NATs were identified by the alignment of full-length cDNAs or expressed sequence tags to genome sequences, but an alternative method for large-scale detection of sense-antisense transcript pairs involves the use of microarrays. In this study we developed a novel protocol to assay sense- and antisense-strand transcription on the 55 K Affymetrix GeneChip Wheat Genome Array, which is a 3' <it>in vitro </it>transcription (3'IVT) expression array. We selected five different tissue types for assay to enable maximum discovery, and used the 'Chinese Spring' wheat genotype because most of the wheat GeneChip probe sequences were based on its genomic sequence. This study is the first report of using a 3'IVT expression array to discover the expression of natural sense-antisense transcript pairs, and may be considered as proof-of-concept.</p> <p>Results</p> <p>By using alternative target preparation schemes, both the sense- and antisense-strand derived transcripts were labeled and hybridized to the Wheat GeneChip. Quality assurance verified that successful hybridization did occur in the antisense-strand assay. A stringent threshold for positive hybridization was applied, which resulted in the identification of 110 sense-antisense transcript pairs, as well as 80 potentially antisense-specific transcripts. Strand-specific RT-PCR validated the microarray observations, and showed that antisense transcription is likely to be tissue specific. For the annotated sense-antisense transcript pairs, analysis of the gene ontology terms showed a significant over-representation of transcripts involved in energy production. These included several representations of ATP synthase, photosystem proteins and RUBISCO, which indicated that photosynthesis is likely to be regulated by antisense transcripts.</p> <p>Conclusion</p> <p>This study demonstrated the novel use of an adapted labeling protocol and a 3'IVT GeneChip array for large-scale identification of antisense transcription in wheat. The results show that antisense transcription is relatively abundant in wheat, and may affect the expression of valuable agronomic phenotypes. Future work should select potentially interesting transcript pairs for further functional characterization to determine biological activity.</p

Effect of ovariectomy on the progression of chronic kidney disease-mineral bone disorder (CKD-MBD) in female Cy/+ rats

Male Cy/+ rats have shown a relatively consistent pattern of progressive kidney disease development that displays multiple key features of late stage chronic kidney disease-mineral bone disorder (CKD-MBD), specifically the development of cortical bone porosity. However, progression of disease in female Cy/+ rats, assessed in limited studies, is more heterogeneous and to date has failed to show development of the CKD-MBD phenotype, thus limiting their use as a practical model of progressive CKD-MBD. Animal and human studies suggest that estrogen may be protective against kidney disease in addition to its established protective effect on bone. Therefore, in this study, we aimed to determine the effect of ovariectomy (OVX) on the biochemical and skeletal manifestations of CKD-MBD in Cy/+ female rats. We hypothesized that OVX would accelerate development of the biochemical and skeletal features of CKD-MBD in female Cy/+ rats, similar to those seen in male Cy/+ rats. Female Cy/+ rats underwent OVX (n = 8) or Sham (n = 8) surgery at 15 weeks of age. Blood was collected every 5 weeks post-surgery until 35 weeks of age, when the rats underwent a 4-day metabolic balance, and the tibia and final blood were collected at the time of sacrifice. OVX produced the expected changes in trabecular and cortical parameters consistent with post-menopausal disease, and negative phosphorus balance compared with Sham. However, indicators of CKD-MBD were similar between OVX and Sham (similar kidney weight, plasma blood urea nitrogen, creatinine, creatinine clearance, phosphorus, calcium, parathyroid hormone, and no cortical porosity). Contrary to our hypothesis, OVX did not produce evidence of development of the CKD-MBD phenotype in female Cy/+ rats

Dielectric spectroscopy of ferroelectric nematic liquid crystals: Measuring the capacitance of insulating interfacial layers

Numerous measurements of the dielectric constant $\epsilon$ of the recently discovered ferroelectric nematic ($N_F$) liquid crystal (LC) phase report extraordinarily large values of $\epsilon^\prime$ (up to ~30,000). We show that what is in fact being measured in such experiments is the high capacitance of the non-ferroelectric, interfacial, insulating layers of nanoscale thickness that bound the $N_F$ material in typical cells. We analyze a parallel-plate cell filled with $N_F$ material of high-polarization $\mathbf{P}$, oriented parallel to the plates at zero applied voltage. Minimization of the dominant electrostatic energy renders $\mathbf{P}$ spatially uniform and orients it to make the electric field in the $N_F$ as small as possible, a condition under which the voltage applied to the cell appears almost entirely across the high-capacity interfacial layers. This coupling of orientation and charge creates a combined polarization-external capacitance (PCG) Goldstone reorientation mode requiring applied voltages orders of magnitude smaller than that of the $N_F$ layer alone to effectively transport charge across the $N_F$ layer. The $N_F$ layer acts as a low-value resistor and the interfacial capacitors as reversible energy storage reservoirs, lowering the restoring force (mass) of the PCG mode and producing strong reactive dielectric behavior. Analysis of data from several experiments on ferroelectric liquid crystals (chiral smectics C, bent-core smectics, and the $N_F$ phase supports the PCG model, showing deriving that deriving dielectric constants from electrical impedance measurements of high-polarization ferroelectric LCs, without properly accounting for the self-screening effects of polarization charge and the capacitive contributions of interfacial layers, can result in overestimation of the $\epsilon^\prime$ values of the LC by many orders of magnitude.Comment: 26 pages of text, 10 figures, 49 references (40 pages total