Effects of Economic Interactions on Credit Risk

We study a credit risk model which captures effects of economic interactions on a firm's default probability. Economic interactions are represented as a functionally defined graph, and the existence of both cooperative, and competitive, business relations is taken into account. We provide an analytic solution of the model in a limit where the number of business relations of each company is large, but the overall fraction of the economy with which a given company interacts may be small. While the effects of economic interactions are relatively weak in typical (most probable) scenarios, they are pronounced in situations of economic stress, and thus lead to a substantial fattening of the tails of loss distributions in large loan portfolios. This manifests itself in a pronounced enhancement of the Value at Risk computed for interacting economies in comparison with their non-interacting counterparts.Comment: 24 pages, 6 figure

Identification of three high molecular mass cysteine proteinases from rat skeletal muscle

AbstractThree cysteine proteinases were isolated from the post-myofibrillar fraction of rat skeletal muscle. Proteinase I preferentially hydrolyzes Z-Phe—Arg-NMec with pH optimum at 8–9. The enzyme activity is stabilized by ATP against thermal inactivation. Proteinase II and III were not resolved by anion-exchange chromatography, by affinity chromatography on Arginine—Sepharose or by gel filtration. Proteinase II, splitting Bz-ValGlyArg-NMec optimally at pH 10–10.5, is inactivated by ATP, whereas Proteinase III, hydrolyzing Suc-AlaAlaPhe-NMec at pH 7–7.5 is not affected by the nucleotide. The molecular mass of proteinase I is about 750 000 and that of proteinase II and III is about 650 000, as determined by gel filtration

Across-Breed EPD Tables For The Year 2016 Adjusted To Breed Differences For Birth Year Of 2014

Factors to adjust the expected progeny differences (EPD) of each of 18 breeds to the base of Angus EPD are reported in the column labeled 6 of Tables 1-8 for birth weight, weaning weight, yearling weight, maternal milk, marbling score, ribeye area, fat thickness, and carcass weight, respectively. An EPD is adjusted to the Angus base by adding the corresponding acrossbreed adjustment factor in column 6 to the EPD. It is critical that this adjustment be applied only to Spring 2016 EPD. Older or newer EPD may be computed on different bases and, therefore, could produce misleading results. When the base of a breed changes from year to year, its adjustment factor (Column 6) changes in the opposite direction and by about the same amount. Breed differences change over time as breeds put selection emphasis on different traits and their genetic trends differ accordingly. Therefore, it is necessary to qualify the point in time at which breed differences are represented. Column 5 of Tables 1-8 contains estimates of the differences between the averages of calves from sires of each breed born in year 2014. Any differences (relative to their breed means) in the samples of sires representing those breeds at the U.S. Meat Animal Research Center (USU.S. Meat Animal Research Center) are adjusted out of these breed difference estimates and the across-breed adjustment factors. The breed difference estimates are reported as progeny differences, e.g., they represent the expected difference in progeny performance of calves sired by average bulls (born in 2014) of two different breeds and out of dams of a third, unrelated breed. In other words, they represent half the differences that would be expected between purebreds of the two breeds

Apparatus for real-time acoustic imaging of Rayleigh-Benard convection

We have designed and built an apparatus for real-time acoustic imaging of convective flow patterns in optically opaque fluids. This apparatus takes advantage of recent advances in two-dimensional ultrasound transducer array technology; it employs a modified version of a commercially available ultrasound camera, similar to those employed in non-destructive testing of solids. Images of convection patterns are generated by observing the lateral variation of the temperature dependent speed of sound via refraction of acoustic plane waves passing vertically through the fluid layer. The apparatus has been validated by observing convection rolls in both silicone oil and ferrofluid.Comment: 20 pages, 11 figures, submitted to the Review of Scientific Instrument

Ultrafast spatio-temporal dynamics of terahertz generation by ionizing two-color femtosecond pulses in gases

We present a combined theoretical and experimental study of spatio-temporal propagation effects in terahertz (THz) generation in gases using two-color ionizing laser pulses. The observed strong broadening of the THz spectra with increasing gas pressure reveals the prominent role of spatio-temporal reshaping and of a plasma-induced blue-shift of the pump pulses in the generation process. Results obtained from (3+1)-dimensional simulations are in good agreement with experimental findings and clarify the mechanisms responsible for THz emission

Growth curves of crossbred cows sired by Hereford, Angus, Belgian Blue, Brahman, Boran, and Tuli bulls, and the fraction of mature body weight and height at puberty

The objective of this study was to evaluate the growth curves of females to determine if mature size and relative rates of maturation among breeds differed. Body weight and hip height data were fitted to the nonlinear function BW = f(age) = A − Bek×age, where A is an estimate of mature BW and k determines the rate that BW or height moves from B to A. Cows represented progeny from 28 Hereford, 38 Angus, 25 Belgian Blue, 34 Brahman, 8 Boran, and 9 Tuli sires. Bulls from these breeds were mated by AI to Angus, Hereford, and U.S. Meat Animal Research Center III composite (1/4 Angus, ¼ Hereford, 1/4 Red Poll, and 1/4 Pinzgauer) cows to produce calves in 1992, 1993, and 1994. These matings resulted in 516 mature cows whose growth curves were subsequently evaluated. Hereford-sired cows tended to have heavier mature BW, as estimated by parameter A, than Angus- (P = 0.09) and Brahman-sired cows(P = 0.06), and were heavier than the other breeds (P \u3c 0.001). Angus-sired cows were heavier than Boran-(P \u3c 0.001) and Tuli-sired cows (P \u3c 0.001), and tended to be heavier than Belgian Blue-sired cows (P = 0.097). Angus-sired cows did not differ from Brahman- sired cows (P = 0.94). Brahman-sired cows had a heavier mature BW than Boran- (P \u3c 0.001), Tuli- (P \u3c 0.001), and Belgian Blue-sired cows (P \u3c 0.04). Angus-sired cows matured faster (k) than cows sired by Hereford (P = 0.03), Brahman (P \u3c 0.001), Boran (P = 0.03), and Tuli (P \u3c 0.001) sires, but did not differ from Belgian Blue-sired (P = 0.13) cows. Brahmansired cows took longer to mature than Boran- (P = 0.03) or Belgian Blue-sired cows (P = 0.003). Belgian Blue-sired cows were faster maturing than Tuli-sired cows (P = 0.02). Brahman-sired cows had reached a greater proportion of their mature BW at puberty than had Hereford- (P \u3c 0.001), Tuli- (P = 0.003), and Belgian Blue-sired cows (P = 0.001). Boran-sired cows tended to have reached a greater proportion of their mature BW at puberty than had Angus-sired cows (P = 0.09), and had reached a greater proportion of their mature BW at puberty than had Hereford- (P \u3c 0.001), Tuli- (P \u3c 0.001), and Belgian Blue-sired cows (P \u3c 0.001). Within species of cattle, the relative range in proportion of mature BW at puberty (Bos taurus 0.56 through 0.58, and Bos indicus 0.60) was highly conserved, suggesting that proportion of mature BW is a more robust predictor of age at puberty across breeds than is absolute weight or age

Growth curves of crossbred cows sired by Hereford, Angus, Belgian Blue, Brahman, Boran, and Tuli bulls, and the fraction of mature body weight and height at puberty

The objective of this study was to evaluate the growth curves of females to determine if mature size and relative rates of maturation among breeds differed. Body weight and hip height data were fitted to the nonlinear function BW = f(age) = A − Bek×age, where A is an estimate of mature BW and k determines the rate that BW or height moves from B to A. Cows represented progeny from 28 Hereford, 38 Angus, 25 Belgian Blue, 34 Brahman, 8 Boran, and 9 Tuli sires. Bulls from these breeds were mated by AI to Angus, Hereford, and U.S. Meat Animal Research Center III composite (1/4 Angus, ¼ Hereford, 1/4 Red Poll, and 1/4 Pinzgauer) cows to produce calves in 1992, 1993, and 1994. These matings resulted in 516 mature cows whose growth curves were subsequently evaluated. Hereford-sired cows tended to have heavier mature BW, as estimated by parameter A, than Angus- (P = 0.09) and Brahman-sired cows(P = 0.06), and were heavier than the other breeds (P \u3c 0.001). Angus-sired cows were heavier than Boran-(P \u3c 0.001) and Tuli-sired cows (P \u3c 0.001), and tended to be heavier than Belgian Blue-sired cows (P = 0.097). Angus-sired cows did not differ from Brahman- sired cows (P = 0.94). Brahman-sired cows had a heavier mature BW than Boran- (P \u3c 0.001), Tuli- (P \u3c 0.001), and Belgian Blue-sired cows (P \u3c 0.04). Angus-sired cows matured faster (k) than cows sired by Hereford (P = 0.03), Brahman (P \u3c 0.001), Boran (P = 0.03), and Tuli (P \u3c 0.001) sires, but did not differ from Belgian Blue-sired (P = 0.13) cows. Brahmansired cows took longer to mature than Boran- (P = 0.03) or Belgian Blue-sired cows (P = 0.003). Belgian Blue-sired cows were faster maturing than Tuli-sired cows (P = 0.02). Brahman-sired cows had reached a greater proportion of their mature BW at puberty than had Hereford- (P \u3c 0.001), Tuli- (P = 0.003), and Belgian Blue-sired cows (P = 0.001). Boran-sired cows tended to have reached a greater proportion of their mature BW at puberty than had Angus-sired cows (P = 0.09), and had reached a greater proportion of their mature BW at puberty than had Hereford- (P \u3c 0.001), Tuli- (P \u3c 0.001), and Belgian Blue-sired cows (P \u3c 0.001). Within species of cattle, the relative range in proportion of mature BW at puberty (Bos taurus 0.56 through 0.58, and Bos indicus 0.60) was highly conserved, suggesting that proportion of mature BW is a more robust predictor of age at puberty across breeds than is absolute weight or age