Study of the Mechanisms of Flux Pinning in Type 2 Superconductors

Flux pinning mechanisms in type-2 semiconductors and specific heat measurements on annealed and deformed pure niobium sample

Steer stress response as affected by genotype and transportation

Bovine cytochrome P450 3A28 is responsible for metabolizing ergot alkaloids that cattle ingest when feeding on endophyte-infested tall fescue grass. The objective of this research was to determine associations among genotype, transportation, and stress responses. Angus crossbred steers (n = 47) were genotyped (CC, CG, or GG) for a single-nucleotide polymorphism (C994G) in cytochrome P450 3A28. Genotypes were determined by polymerase chain reaction (PCR) amplification followed by restriction enzyme (Alu1) digestion. Steers were backgrounded on a mixedcultivar tall fescue pasture. Following the stocker phase, steers were transported to the feedlot for finishing. Stress responses were determined 27 h prior to, and 6 and 20 h after transport. Plasma concentrations of prolactin and cortisol, and white blood cell expression of prolactin, cytochrome P450, tumor necrosis factor-alpha, and short form prolactin receptor were our indicators of stress. Both time and genotypic effects were determined. Time (P \u3c 0.05) relative to transportation was associated with expression of all four genes tested. In addition, plasma concentrations of cortisol and prolactin, as well as their ratio were affected (P \u3c 0.05) by time. In contrast, neither genotype nor the interaction between genotype and time affected (P \u3e 0.1) our stress indicators. In previous studies, C994G genotype has been associated with cattle productivity; however, those effects were not observed in this study

Thermally activated escape rates of uniaxial spin systems with transverse field

Classical escape rates of uniaxial spin systems are characterized by a prefactor differing from and much smaller than that of the particle problem, since the maximum of the spin energy is attained everywhere on the line of constant latitude: theta=const, 0 =< phi =< 2*pi. If a transverse field is applied, a saddle point of the energy is formed, and high, moderate, and low damping regimes (similar to those for particles) appear. Here we present the first analytical and numerical study of crossovers between the uniaxial and other regimes for spin systems. It is shown that there is one HD-Uniaxial crossover, whereas at low damping the uniaxial and LD regimes are separated by two crossovers.Comment: 4 PR pages, 3 figures, final published versio

Field dependence of the temperature at the peak of the ZFC magnetization

The effect of an applied magnetic field on the temperature at the maximum of the ZFC magnetization, $M_{ZFC}$, is studied using the recently obtained analytic results of Coffey et al. (Phys. Rev. Lett. {\bf 80}(1998) 5655) for the prefactor of the N\'{e}el relaxation time which allow one to precisely calculate the prefactor in the N\'{e}el-Brown model and thus the blocking temperature as a function of the coefficients of the Taylor series expansion of the magnetocrystalline anisotropy. The present calculations indicate that even a precise determination of the prefactor in the N\'{e}el-Brown theory, which always predicts a monotonic decrease of the relaxation time with increasing field, is insufficient to explain the effect of an applied magnetic field on the temperature at the maximum of the ZFC magnetization. On the other hand, we find that the non linear field-dependence of the magnetization along with the magnetocrystalline anisotropy appears to be of crucial importance to the existence of this maximum.Comment: 14 LaTex209 pages, 6 EPS figures. To appear in J. Phys.: Condensed Matte

Integral Relaxation Time of Single-Domain Ferromagnetic Particles

The integral relaxation time \tau_{int} of thermoactivating noninteracting single-domain ferromagnetic particles is calculated analytically in the geometry with a magnetic field H applied parallel to the easy axis. It is shown that the drastic deviation of \tau_{int}^{-1} from the lowest eigenvalue of the Fokker-Planck equation \Lambda_1 at low temperatures, starting from some critical value of H, is the consequence of the depletion of the upper potential well. In these conditions the integral relaxation time consists of two competing contributions corresponding to the overbarrier and intrawell relaxation processes.Comment: 8 pages, 3 figure

Koinonia

The Purpose of Higher Education President\u27s Corner The Editor\u27s Disk CoCCA: Volunteer Service...Required? & Hot Ideas New Professionals Retreat, ACSD Archives Announcement Book Preview: What on Earth Are We Doing? ACSD Northwest Regional Activity Career Development: Much More Than Placementhttps://pillars.taylor.edu/acsd_koinonia/1025/thumbnail.jp

Quantum Thermoactivation of Nanoscale Magnets

The integral relaxation time describing the thermoactivated escape of a uniaxial quantum spin system interacting with a boson bath is calculated analytically in the whole temperature range. For temperatures T much less than the barrier height \Delta U, the level quantization near the top of the barrier and the strong frequency dependence of the one-boson transition probability can lead to the regularly spaced deep minima of the thermoactivation rate as a function of the magnetic field applied along the z axis.Comment: 4 pages, no figures, rejected from Phys. Rev. Let

Book Reviews

Reviews of the following books: Was Baseball Really Invented in Maine? by Will Anderson; Acadian Hard Times: The Farm Security Administration in Maine\u27s St. John Valley, 1940-1943 by C. Stewart Doty; The Latchstring Was Always Out: A History of Lodging Hospitality and Tourism in Bartlett, New Hampshire by Aileen M. Carroll; A Fair Field and No Favor: A Concise History of the Maine State Grange by Stanley Russell Howe; Dell Turner: The Stories of His Life by John T. Meader; Hail Britannia: Maine Pewter and Silverplate: An Exhibition of Maine Britannia Ware and Silverplate, 1829-1941, in the Collections of the Maine State Museum, May 15, 1992-May 15, 1993 by Edwin A. Churchil

Linking Community Service, Learning, and Enviromental Analytical Chemistry

In 1994, during a tour of the then-new natural sciences building- a $43 million teaching and research complex fully equipped with the latest in technology and instrumentation for chemistry and geology courses-a member of the Buffalo Public Schools Board of Education asked, How can the community [that paid for it] have access to this teaching and research equipment? That question triggered the effort reported here - a program to better link teaching and research to community service