Sparse Quantum Codes from Quantum Circuits

Sparse quantum codes are analogous to LDPC codes in that their check operators require examining only a constant number of qubits. In contrast to LDPC codes, good sparse quantum codes are not known, and even to encode a single qubit, the best known distance is O(√n log(n)), due to Freedman, Meyer and Luo. We construct a new family of sparse quantum subsystem codes with minimum distance n[superscript 1 - ε] for ε = O(1/√log n). A variant of these codes exists in D spatial dimensions and has d = n[superscript 1 - ε - 1/D], nearly saturating a bound due to Bravyi and Terhal. Our construction is based on a new general method for turning quantum circuits into sparse quantum subsystem codes. Using this prescription, we can map an arbitrary stabilizer code into a new subsystem code with the same distance and number of encoded qubits but where all the generators have constant weight, at the cost of adding some ancilla qubits. With an additional overhead of ancilla qubits, the new code can also be made spatially local.National Science Foundation (U.S.) (Grant CCF-1111382)United States. Army Research Office (Contract W911NF-12-1-0486

Entanglement Perturbation Theory for Antiferromagnetic Heisenberg Spin Chains

A recently developed numerical method, entanglement perturbation theory (EPT), is used to study the antiferromagnetic Heisenberg spin chains with z-axis anisotropy $\lambda$ and magnetic field B. To demonstrate the accuracy, we first apply EPT to the isotropic spin-1/2 antiferromagnetic Heisenberg model, and find that EPT successfully reproduces the exact Bethe Ansatz results for the ground state energy, the local magnetization, and the spin correlation functions (Bethe ansatz result is available for the first 7 lattice separations). In particular, EPT confirms for the first time the asymptotic behavior of the spin correlation functions predicted by the conformal field theory, which realizes only for lattice separations larger than 1000. Next, turning on the z-axis anisotropy and the magnetic field, the 2-spin and 4-spin correlation functions are calculated, and the results are compared with those obtained by Bosonization and density matrix renormalization group methods. Finally, for the spin-1 antiferromagnetic Heisenberg model, the ground state phase diagram in $\lambda$ space is determined with help of the Roomany-Wyld RG finite-size-scaling. The results are in good agreement with those obtained by the level-spectroscopy method.Comment: 12 pages, 14 figure

Gonadotropin-releasing hormone increased pregnancy risk in suckled beef cows not detected in estrus and subjected to a split-time artificial insemination program

Citation: Hill, S. L., Grieger, D. M., Olson, K. C., Jaeger, J. R., Dahlen, C. R., Crosswhite, M. R., . . . Stevenson, J. S. (2016). Gonadotropin-releasing hormone increased pregnancy risk in suckled beef cows not detected in estrus and subjected to a split-time artificial insemination program. Journal of Animal Science, 94(9), 3722-3728. doi:10.2527/jas2016-0582We hypothesized that GnRH would increase pregnancy risk (PR) in a split-time AI program for cows in which estrus was not detected. A total of 1,236 suckled beef cows at 12 locations in 3 states (Colorado, Kansas, and North Dakota) were enrolled. Before applying the fixed-time AI program, BCS was assessed. Cows were treated on d -7 with a progesterone insert concurrent with 100 mu g GnRH and on d 0 with 25 mg PGF(2 alpha) plus removal of the insert. Estrus-detection patches were affixed to cows at insert removal. Estrus was defined to have occurred when an estrus-detection patch was >50% colored (activated). Cows in estrus by 65 h (n = 758; 61.3% of all cows) were randomly allocated to 2 treatments: 1) 100 mu g GnRH and early + GnRH (E+G; n = 373) or 2) AI only at 65 h (early -no GnRH [E-G]; n = 385). The remaining cows were randomly allocated to 2 treatments: 1) 5(L+G; n = 252) or 2) AI only at 84 h (late no GnRH [L-G]; n = 226). Pregnancy was determined 35 d after AI via transrectal ultrasound. Pregnancy risk did not differ (P = 0.68) between E+G and E-G cows (61.9 vs. 60.4%, respectively). Conversely, for cows inseminated at 84 h, PR was greater (P = 0.01) in cows that received GnRH (L+G) compared with their herd mates not receiving GnRH (L-G; 41.7 vs. 30.8%, respectively). Of those cows not detected in estrus by 65 h, 42.1% were detected by 84 h, for a total expression of estrus by all cows of 77.6%. Administration of GnRH increased (P < 0.01) PR in cows not detected in estrus by 84 h (+ GnRH = 33.4% [n = 146] vs. no GnRH = 15.0% [n = 128]) but had no effect in cows expressing estrus by 84 h (+ GnRH = 65.3% [n = 103] vs. no GnRH = 61.7% [n = 97]). Neither estrus expression by 65 or 84 h nor PR was influenced by BCS, parity, or days postpartum at AI. Cows had greater PR when they had been detected in estrus before AI, and PR was improved by administration of GnRH at 65 h after insert removal in cows that were not detected in estrus and inseminated at 84 h

Gonadotropin-Releasing Hormone Increased Pregnancy in Suckled Beef Cows Not Detected in Estrus and Subjected to a Split-Time Artificial Insemination Program

Estrus-synchronization programs allow insemination of all females in a herd at one fixed time on the first day of the breeding season. Inseminating cows after they have expressed estrus increases pregnancy rate (PR) compared with cows that do not display estrus in a timed AI (TAI) program. Identification of estrus status can be facilitated by using estrus-detection patches. Varying AI timing according to estrus status has increased PR in some previous studies. Reducing the number of injections in a TAI program decreases labor requirements, stress on cows, and overall cost of the program. Previous studies have demonstrated that PR is not compromised in cows displaying estrus when the GnRH injection administered at AI is eliminated. A split-time AI program decreases the time between estrus expression and insemination compared with a single fixed-time AI when the first AI occurs before the recommended standard 60- to 66-h fixed time. Previous research has demonstrated that delaying AI results in approxi­mately 50% more cows displaying estrus when compared with a single insemination time. Eliminating the GnRH injection at AI for cows displaying estrus in a split TAI program can reduce the number of GnRH injections required and the program cost. The objective of this study was to test the hypothesis that GnRH injection concurrent with split TAI program improves PR only in cows not displaying estrus

Chronic Allergic Inflammation Causes Vascular Remodeling and Pulmonary Hypertension in Bmpr2 Hypomorph and Wild-Type Mice

Loss-of-function mutations in the bone morphogenetic protein receptor type 2 (BMPR2) gene have been identified in patients with heritable pulmonary arterial hypertension (PAH); however, disease penetrance is low, suggesting additional factors play a role. Inflammation is associated with PAH and vascular remodeling, but whether allergic inflammation triggers vascular remodeling in individuals with BMPR2 mutations is unknown. Our goal was to determine if chronic allergic inflammation would induce more severe vascular remodeling and PAH in mice with reduced BMPR-II signaling. Groups of Bmpr2 hypomorph and wild-type (WT) Balb/c/Byj mice were exposed to house dust mite (HDM) allergen, intranasally for 7 or 20 weeks to generate a model of chronic inflammation. HDM exposure induced similar inflammatory cell counts in all groups compared to controls. Muscularization of pulmonary arterioles and arterial wall thickness were increased after 7 weeks HDM, more severe at 20 weeks, but similar in both groups. Right ventricular systolic pressure (RVSP) was measured by direct cardiac catheterization to assess PAH. RVSP was similarly increased in both HDM exposed groups after 20 weeks compared to controls, but not after 7 weeks. Airway hyperreactivity (AHR) to methacholine was also assessed and interestingly, at 20 weeks, was more severe in HDM exposed Bmpr2 hypomorph mice versus WT. We conclude that chronic allergic inflammation caused PAH and while the severity was mild and similar between WT and Bmpr2 hypomorph mice, AHR was enhanced with reduced BMPR-II signaling. These data suggest that vascular remodeling and PAH resulting from chronic allergic inflammation occurs independently of BMPR-II pathway alterations

ASSESSING THE MENSTRUATION-RELATED CHANGES OF HEMATOCRIT AND ITS INFLUENCE ON MAXIMAL EXERCISE PERFORMANCE

Heenan R, Goodheart C, Brady G, Albers M, Crosswhite, P. Gonzaga University, Spokane, WA. Hematocrit (Hct) is a ratio of red blood cells to plasma in a blood sample. When this ratio increases, the ability to carry oxygen increases. When biological females go through the menstrual cycle, time durations of blood loss result in a reduced oxygen-carrying capacity. PURPOSE: This study aimed to investigate whether a change in hematocrit due to menstruation-associated blood loss significantly affects maximal exercise performance. METHODS: We conducted VO2max tests on four moderately trained females ages 18-22 yr. Each subject completed three VO2maxtests on a bike: a familiarization day and two test days. Test day 1 corresponded to day 7 of their cycle, when hematocrit was predicted to be the lowest. Test day 2 corresponded to day 14 of their cycle when hematocrit was predicted to be fully recovered. RESULTS: Statistical significance was found between absolute VO2max on test day 1 and test day 2 (p=0.004). This was further supported by a significant difference in end wattage between test day 1 and test day 2 (p= 0.037 ) and final time between test day 1 and test day 2 (p=0.041). As anticipated, there was a significant difference in hematocrit between test day 1 and test day 2 (p=0.038). No statistically significant difference was found between relative VO2max on test day 1 and test day 2 (p= 0.068). CONCLUSION: We concluded that menstruation-associated blood loss points to significant changes in hematocrit which further affects maximal exercise performance in college-aged females