Evidence of shallow fault zone strengthening after the 1992 M7.5 landers, california, earthquake

Repeated seismic surveys of the Landers, California, fault zone that ruptured in the magnitude (M) 7.5 earthquake of 1992 reveal an increase in seismic velocity with time. P, S, and fault zone trapped waves were excited by near-surface explosions in two locations in 1994 and 1996, and were recorded on two linear, three-component seismic arrays deployed across the Johnson Valley fault trace. The travel times of P and S waves for identical shot-receiver pairs decreased by 0.5 to 1.5 percent from 1994 to 1996, with the larger changes at stations located within the fault zone. These observations indicate that the shallow Johnson Valley fault is strengthening after the main shock, most likely because of closure of cracks that were opened by the 1992 earthquake. The increase in velocity is consistent with the prevalence of dry over wet cracks and with a reduction in the apparent crack density near the fault zone by approximately 1.0 percent from 1994 to 1996.     

Efficacy of doxorubicin as an induction agent for cats with lymphosarcoma

OBJECTIVE: To determine the efficacy of doxorubicin when used alone in inducing remission in cats with lymphosarcoma. DESIGN: Prospective multi-institutional study of naturally occurring disease. METHODS: Cases were accrued from veterinary institutions in Australia and New Zealand after obtaining consent from informed owners. Cats were treated with doxorubicin every 3 weeks for three treatments. If there was no response to the first dose of doxorubicin or if the cat relapsed during the doxorubicin regimen, the cat was withdrawn from the trial and either euthanased or treated with other agents. Age, breed, gender and anatomic site of the lymphosarcoma (multicentric, alimentary, mediastinal, extranodal) were recorded for each cat. Clinical remission was assessed before each treatment by physical examination, radiography, ultrasonography and computed tomography where appropriate. Complete remission was defined as the disappearance of all clinical signs and clinically detectable tumour. RESULTS: Twenty-one cases were accrued over a 2-year-period but only 19 were available for data analysis. Young Siamese cats were over-represented and all cats with mediastinal tumours were young Siamese. There was a significant difference between the mean ages of cats with mediastinal or multicentric lymphosarcoma (mean +/- SD: 3.5 +/- 3.0 and 4.3 +/- 2.6 years, respectively) and cats with alimentary or extranodal LSA (11.4 +/- 0.9 and 11.0 +/- 0.9 years, respectively). Of 19 cats treated with doxorubicin alone, 6 (32%) had complete remission, 6 (32%) had partial remission and 7 (36%) did not respond. CONCLUSIONS: The results suggest that doxorubicin cannot be recommended as a single agent for treatment of feline lymphosarcoma because of the rather poor remission rate achieved.     

Molecular epidemiology of clinical isolates of Pseudomonas aeruginosa isolated from horses in Ireland

Clinical isolates (n = 63) of Pseudomonas aeruginosa obtained from various sites in 63 horses were compared using ERIC2 RAPD PCR to determine their genetic relatedness. Resulting banding patterns (n = 24 genotypes) showed a high degree of genetic heterogeneity amongst all isolates examined, indicating a relative non-clonal relationship between isolates from these patients, employing this genotyping technique. This study characterised 63 clinical isolates into 24 distinct genotypes, with the largest cluster (genotype E) accounting for 10/63 (15.9%) of the isolates. ERIC2 RAPD PCR proved to be a highly discriminatory molecular typing tool of P. aeruginosa in isolates recovered from horses. With the adoption of several controls to aid reproducibility, this technique may be useful as an alternative to PFGE, particularly in epidemiological investigations of outbreaks where speed may be a significant parameter. This is the first report of clonal heterogeneity amongst P. aeruginosa from horses and demonstrated that ERIC RAPD PCR is a rapid method for the examination of this species in horses, which may be useful in outbreak analysis.     

OC1Effects of Cryopreservation on the Expression of Glut‐3, Glut‐5 and As‐A Proteins in Iberian Boar Sperm Membranes

In order to determine the injure produced in boar spermatozoa through cryopreservation process, we analyzed the expression of the hexose transporters Glut‐3 and Glut‐5 and the zona pellucida binding protein As‐A (P68) in three different steps of the freezing‐thawed protocol: at 17°C (fresh BTS‐diluted semen, 1 : 2 v/v, step 1), at 5°C (after glycerol addition; step 2), and post‐thawing (step 3). All sperm analyses were carried out with immunogold techniques under electronic microscopy. For this study eight healthy post‐pubertal Iberian boars were submitted to a collection of twice per week through 3 months, evaluating two ejaculates from each boar. Glut‐3 maintains the expression in the acrosome region post‐thawing but not along the tail where is reduced. The expression of Glut‐5 and As‐A is majority located at the post‐acrosome region of the spermatozoa at step 1, but in step 2 and step 3 this expression is relocated to sperm tail area. In conclusion, while cryopreservation affects the localization and the expression of Glut‐3 and Glut‐5, its fertilizing capacity is not significantly reduced. The stabilization of boar semen at 5°C was found to be the most crucial step for sperm survival.     

Associations between hoof shape and the position of the frontal plane ground reaction force vector in walking horses

AIMS: To determine the frontal plane position of the ground reaction force vector at its centre of pressure under the hoof of walking horses, and its projection through the distal limb joints, and to relate this to hoof geometric measurements.

METHODS: Reflective markers were glued to the forelimb hooves and skin of 26 horses, over palpable landmarks representing centres of the coffin, fetlock and carpal joints, and the dorsal toe at its most distal point. A 4-camera kinematic system recorded the position of these markers as the horse walked in hand across a force platform, to generate a frontal plane representation of the ground reaction force vector passing between the markers at the joints. The position of the vector was calculated as the relative distance between the lateral (0%) and medial (100%) markers at each joint. Digital photos were taken of the hoof in frontal and sagittal views to determine hoof geometric measurements. Associations between these and the position of the force vector at each joint were examined using Pearson correlation coefficients.

RESULTS: Mean vector position for both forelimbs at the toe, coffin, fetlock and carpal joint was 50.1 (SD 8.9), 53.0 (SD 9.2), 54.6 (SD 11.4) and 50.5 (SD17.3)%, respectively, of the distance between the lateral and medial sides of the joint in the frontal plane. Across all four joints, the vector position was slightly more medial (2–4%) for the right than left limb (p>0.05). Medial hoof wall angle was correlated (p<0.05) with force vector position at the fetlock (r=?0.402) and carpal (r=?0.317) joints; lateral hoof wall angle with vector position at the toe (r=0.288) and carpal (r=?0.34) joint, and medial hoof wall height with vector position at the fetlock (r=?0.306) and carpal (r=?0.303) joints.

CONCLUSION: The position of the two-dimensional frontal plane ground reaction force vector at the toe, and at the fetlock and carpal joints was associated with hoof shape. Mediolateral hoof balance has been shown in vitro to affect articular forces, which may be a factor in development of joint disease. The effect of hoof shape needs to be evaluated at faster gaits to determine the potential for joint injury in the presence of larger forces.     

Concentrations of buparvaquone in milk and tissue of dairy cows

AIM: To determine the concentration of the anti-theilerial drug buparvaquone in the milk and tissue of dairy cattle following treatment with two different formulations, and to assess the effect of clinical theileriosis on the concentration of buparvaquone in milk.

METHODS: Healthy lactating dairy cows (n=25) were injected once (Day 0) I/M with 2.5?mg/kg of one of two formulations of buparvaquone (Butalex; n=12 or Bupaject; n=13). Milk samples were collected from all cows daily until Day 35. Five cows were slaughtered on each of Days 56, 119, 147, 203 and 328, and samples of liver, muscle and injection site tissue collected. Milk samples were also collected from cows (n=14) clinically affected with theileriosis for up to 21 days after treatment with buparvaquone. Milk and tissue samples were analysed by liquid chromatography-mass spectrometry; limits of detection (LOD) were 0.00018?mg/kg for muscle and 0.00023?mg/L for milk. Concentrations of buparvaquone in milk and tissues were log₁₀-transformed for analysis using multivariate models.

RESULTS: In healthy cows, concentrations of buparvaquone in milk declined with time post-treatment (p<0.001), but were above the LOD in 11 of 25 cows at Day 35. Concentration in milk was higher one day after treatment in cows treated with Butalex than in cows treated with Bupaject, but not different thereafter (p=0.007). Concentrations of buparvaquone in muscle were below the LOD for four of five animals at Day 119 and for all animals by Day 147, but were above the LOD at the injection site of one cow, and in the liver of three cows at Day 328. Tissue concentrations did not differ with formulation nor was there a formulation by time interaction (p>0.3).

Concentrations of buparvaquone in the milk of clinically affected animals were not different from those of healthy animals at 1 and 21 days post-treatment (p=0.72). Between 21 and 25 days post-treatment concentrations were below the LOD in 9/14 milk samples from clinically affected cows.

CONCLUSIONS: Detectable concentrations of buparvaquone were found in the milk of some cows for at least 35 days and in the liver and injection site of some cows until at least 328 days after injection. There were no biologically meaningful differences in milk or tissue concentrations between the formulations, or in the milk concentrations for cows that were clinically affected compared with those that were healthy at the time of treatment.     

Vertical Flux of Biogenic Carbon in the Ocean: Is There Food Web Control?

Models of biogenic carbon (BC) flux assume that short herbivorous food chains lead to high export, whereas complex microbial or omnivorous food webs lead to recycling and low export, and that export of BC from the euphotic zone equals new production (NP). In the Gulf of St. Lawrence, particulate organic carbon fluxes were similar during the spring phytoplankton bloom, when herbivory dominated, and during nonbloom conditions, when microbial and omnivorous food webs dominated. In contrast, NP was 1.2 to 161 times greater during the bloom than after it. Thus, neither food web structure nor NP can predict the magnitude or patterns of BC export, particularly on time scales over which the ocean is in nonequilibrium conditions.     

Simultaneous Measurement of Local Gain and Electron Density in X-ray Lasers

X-ray lasers (XRLs) have experimental average gains that are significantly less than calculated values and a persistently low level of spatial coherence. An XRL has been used both as an injected signal to a short XRL amplifier and as an interferometer beam to measure two-dimensional local gain and density profiles of the XRL plasma with a resolution near 1 micrometer. The measured local gain is in agreement with atomic models but is unexpectedly spatially inhomogeneous. This inhomogeneity is responsible for the low level of spatial coherence observed and helps explain the disparity between observed and simulated gains.     

A Far-Field Hydrothermal Plume from Loihi Seamount

An extensive helium plume in the north central Pacific emanates from Loihi Seamount on the flanks of Hawaii. The maximum helium signal is found at a depth of about 1100 meters, the same depth as the near-field plume directly above Loihi Seamount. Although this helium plume is strongest near Hawaii, where the 3He/4He ratio at a depth of about 1100 meters reaches values 28 percent above the atmospheric ratio, it can be detected quite clearly at latitude 24°N, over 400 kilometers to the north. Excess 3He is also present on the same isopycnal between 15°N and 20°N at 135°W, some 2000 kilometers east of the Hawaiian Islands.