Effects of Magnetic Order on the Upper Critical Field of UPt3_3

I present a Ginzburg-Landau theory for hexagonal oscillations of the upper critical field of UPt$_3$ near $T_c$. The model is based on a $2D$ representation for the superconducting order parameter, $\vec{\eta}=(\eta_1,\eta_2)$, coupled to an in-plane AFM order parameter, $\vec{m}_s$. Hexagonal anisotropy of $H_{c2}$ arises from the weak in-plane anisotropy energy of the AFM state and the coupling of the superconducting order parameter to the staggered field. The model explains the important features of the observed hexagonal anisotropy [N. Keller, {\it et al.}, Phys. Rev. Lett. {\bf 73}, 2364 (1994).] including: (i) the small magnitude, (ii) persistence of the oscillations for $T\rightarrow T_c$, and (iii) the change in sign of the oscillations for $T> T^{*}$ and $T< T^{*}$ (the temperature at the tetracritical point). I also show that there is a low-field crossover (observable only very near $T_c$) below which the oscillations should vanish.Comment: 9 pages in a RevTex (3.0) file plus 2 postscript figures (uuencoded). Submitted to Physical Review B (December 20, 1994)

Resynchronization of Lactating Dairy Cows at Open Pregnancy Diagnosis Based on the Presence or Absence of a Corpus Luteum: A Practical Approach

Lactating Holstein cows in three herds were enrolled in a study at the time of nonpregnancy diagnosis. Cows were assigned to a resynchronization program based on ovarian structures determined by transrectal ultrasonography. Three resynchronization treatments were employed starting on the day of open diagnosis to test: (1) accuracy of ultrasound technician’s ability to identify a functional corpus luteum (CL); (2) whether an initial GnRH injection is required to start resynchronization when a CL is present at nonpregnant diagnosis (Short Synch: PGF2α — 24 hours — PGF2α — 32 hours — GnRH — 16 hours — timed artificial insemination [AI]); and (3) whether applying progesterone to cows without a CL as part of a traditional Ovsynch program (CIDR + Ovsynch: GnRH + CIDR insert — 7 days — PGF2α + CIDR removal — 24 hours — PGF2α — 32 hours — GnRH — 16 hours — timed AI) would be equivalent to a standard Ovsynch program (same as CIDR-Ovsynch treatment but no CIDR was applied). Treatments produced similar proportions of pregnancies per AI, with a tendency for increased fertility when the first injection of GnRH was administered as part of a standard Ovsynch. The technician’s ability to detect a functional CL was more accurate when the CL visualized was actually functional (progesterone ≥ 1 ng/mL) than when it was not functional (progesterone \u3c 1 ng/mL). Although pregnancy outcomes tended to improve when cows were treated with Ovsynch compared with Short Synch, when a functional CL was accurately detected, pregnancy outcomes did not differ. Technician accuracy for detecting a functional CL is important for improving pregnancy outcomes when applying the Short Synch treatment

High frequency sound in superfluid 3He-B

We present measurements of the absolute phase velocity of transverse and longitudinal sound in superfluid 3He-B at low temperature, extending from the imaginary squashing mode to near pair-breaking. Changes in the transverse phase velocity near pair-breaking have been explained in terms of an order parameter collective mode that arises from f-wave pairing interactions, the so-called J=4- mode. Using these measurements, we establish lower bounds on the energy gap in the B-phase. Measurement of attenuation of longitudinal sound at low temperature and energies far above the pair-breaking threshold, are in agreement with the lower bounds set on pair-breaking. Finally, we discuss our estimations for the strength of the f-wave pairing interactions and the Fermi liquid parameter, F4s.Comment: 15 pages, 8 figures, accepted to J. Low Temp. Phy

Dose and Frequency of PGF2α Administration to Lactating Dairy Cows Exposed to Presynchronization and Either Five- or Seven-day Ovsynch Protocols: Ovulation, Luteolysis, and Pregnancy Rates

Lactating Holstein cows in one herd were milked three times daily and enrolled in a 2 × 2 × 2 factorial design with eight treatments before first postpartum artificial insemination (AI). These treatments were employed to test ovulatory, progesterone, and luteolytic outcomes to three main effects: (1) two GnRH-PGF2α presynchronization programs (PG-3-G vs. Double Ovsynch); (2) 5- vs. 7-day Ovsynch-duration programs; and (3) two doses (25 mg on consecutive days) or one dose (50 mg) of PGF2α administered before timed AI. Results from this experiment demonstrate no differences in the presynchronization treatments of PG-3-G vs. Double Ovsynch; both are effective in initiating estrous cycles during warm-hot vs. cool-cold seasons. Although ovulatory responses were similar after the first GnRH administration, Double Ovsynch cows tended to have greater ovulation responses after the second GnRH administration. The single large, one-time administered 50-mg dose was effective in causing luteolysis in the 7-day program but slightly less effective in the 5-day program. Thus, when using the shorter 5-day program, the two 25-mg PGF2α doses administered 24 hours apart are recommended. Insufficient numbers of cows were treated to make conclusions about pregnancy outcomes in this one-herd study. Pregnancy rates, however, were reduced in 5-day Ovsynch program when the single large 50-mg dose of PGF2α was employed

Resynchronizing Returns to Estrus after a Prior Insemination

In two experiments, GnRH and a progesterone insert (CIDR) were applied to cows after insemination (day 0) to reprogram or synchronize the returning estrus of cows that failed to conceive to that previous insemination. The combination of GnRH (day 14) and a CIDR insert (days 17 to 24) in experiment 1 (n = 347 cows) increased the proportion of nonpregnant cows returning to estrus before pregnancy diagnosis on day 32 by 7.4 percentage points, increased the synchrony of their return by 24.4 percentage points, but delayed that return by 2.3 days compared with controls. In experiment 2 (n = 863 cows), use of GnRH alone (day 7), a CIDR insert alone (days 14 to 21), or in combination, failed to increase the proportion of nonpregnant cows in estrus before pregnancy diagnosis on day 32, but cows receiving the CIDR insert had increased synchrony of estrus by 24 to 34 percentage points compared with cows that did not receive a CIDR insert. In both experiments, the treatment of cows with GnRH or GnRH + CIDR insert increased the pretreatment pregnancy rate by 7.1 to 9.5 percentage points. We conclude that administering GnRH with or without a CIDR insert to resynchronize returns to estrus did not significantly improve the proportion of nonpregnant cows reinseminated before pregnancy diagnosis

Imaginary Squashing Mode Spectroscopy of Helium Three B

We have made precision measurements of the frequency of a collective mode of the superfluid 3He-B order parameter, the J=2- imaginary squashing mode. Measurements were performed at multiple pressures using interference of transverse sound in an acoustic cavity. Transverse waves propagate in the vicinity of this order parameter mode owing to off-resonant coupling. At the crossing of the sound mode and the order parameter mode, the sound wave is strongly attenuated. We use both velocity and attenuation measurements to determine precise values of the mode frequency with a resolution between 0.1% and 0.25%.Comment: 6 pages, 4 figures, submitted to proceedings of Quantum Fluids and Solids (QFS) Conference 2006; revised 9/26/0