Efficient feedback controllers for continuous-time quantum error correction

We present an efficient approach to continuous-time quantum error correction that extends the low-dimensional quantum filtering methodology developed by van Handel and Mabuchi [quant-ph/0511221 (2005)] to include error recovery operations in the form of real-time quantum feedback. We expect this paradigm to be useful for systems in which error recovery operations cannot be applied instantaneously. While we could not find an exact low-dimensional filter that combined both continuous syndrome measurement and a feedback Hamiltonian appropriate for error recovery, we developed an approximate reduced-dimensional model to do so. Simulations of the five-qubit code subjected to the symmetric depolarizing channel suggests that error correction based on our approximate filter performs essentially identically to correction based on an exact quantum dynamical model

Agronomic and Economic Performance Characteristics of Conventional and Low-External-Input Cropping Systems

A 22-acre field experiment was conducted in Boone, IA, from 2003–2006 to test the hypothesis that low-external-input(LEI) cropping systems can produce yields and profits that match or exceed those obtained from conventional systems. A conventionally managed 2-year rotation system [corn (Zea mays L.)/soybean (Glycine max (L.) Merr.)] was compared with a 3-year LEI rotation system [corn/soybean/small grain + red clover (Trifolium pratense L.)], and a 4-year LEI rotation system [corn/soybean/small grain + alfalfa (Medicago sativa L.)/alfalfa]. Triticale (× Triticosecale Wittmack) was used as the small grain in 2003–2005; oat (Avena sativa L.) was used in 2006. Over the period of 2003– 2006, synthetic N fertilizer use was 59% and 74% lower in the 3- and 4-year systems, respectively, compared with the 2-year system. Similarly, herbicide use was reduced 76% and 82% in the 3- and 4-year systems

Galois theory and Lubin-Tate cochains on classifying spaces

We consider brave new cochain extensions F(BG +,R) → F(EG +,R), where R is either a Lubin-Tate spectrum E n or the related 2-periodic Morava K-theory K n , and G is a finite group. When R is an Eilenberg-Mac Lane spectrum, in some good cases such an extension is a G-Galois extension in the sense of John Rognes, but not always faithful. We prove that for E n and K n these extensions are always faithful in the K n local category. However, for a cyclic p-group C p r, the cochain extension F(BC p r +,E n ) → F(EC p r +, E n ) is not a Galois extension because it ramifies. As a consequence, it follows that the E n -theory Eilenberg-Moore spectral sequence for G and BG does not always converge to its expected target

GM 20. Evidence for the existence of a major gene influencing hair Length and heat tolerance in bos taurus cattle

A total of 28 calves from Angus sires and Senepol × Hereford or Hereford × Senepol dams were evaluated for hair length, rectal temperatures, respiration rates, and weights. In addition, ten purebred Angus calves were included in the study as control. Measurements were taken on three consecutive weeks during the hot summer months and also during the cooler late fall. Length of the hair was evaluated using a subjective system of classification (1 - 4). The lowest values describe the typical extremely short hair of pure Senepol cattle and of its crossings F1 with Bos taurus. Twelve of the 28 calves were thus coded as slick-haired and 16 as normal-haired; this ratio does not differ significantly from the 1:1 ratio. Rectal temperature (RT) of the yearling calves of short hair was smaller (P<.02) that the one of the A in two of the dates in the summer and two of the dates in fall sessions. The TR of yearling calves 25 % S of short hair was smaller (P<.04) that of its contemporaries of normal hair in two of the three dates in the summer. TR of yearling calves 25 % Senepol calves of bulls A and with normal coat, was not different (P>.07) of the A in any of the dates. A group of 15 yearling calves of Charolais bulls in cows F1 A × S it was classified by length of hair to the end of September. Seven of these yearling calves were classified as short hair and eight like normal hair. These data suggest a greater gene for length of the hair and tolerance to the heat it could exist in the Senepol breed

GM 16. Sire effects on postweaning growth and carcass characteristics in pubered Brahman cattle

A progeny test for postweaning growth and carcass characteristics was conducted on five purebred Brahman sires. Data presented here are from the progeny of five sires that were tested the first year of a multiyear study that is planned to evaluate approximately 25 sires. There was no effect of sire on initial body weight, but sire effects on average daily gain and final body weight were significant (P<.01). Hot carcass weight (P<.001) and ribeye area (P<.01). Sire affected dressing percentage (P<.001), but there was no effect of sire on USDA yield grade. There were no differences among sires in tenderness scored by sensory panel on steaks aged for 14 days or measured by Warner-Bratzler shear on steaks aged for 7, 14 or 21 days. This progeny test of five Brahman sires revealed genetic differences in postweaning rate of gain and carcass quality grade. Data from additional sires will be required to demonstrate genetic differences in tenderness