Measurement of the speed-of-light perturbation of free-fall absolute gravimeters

We report on a direct measurement of the relativistic Doppler shift with a commercial free-fall absolute gravimeter of the type FG5X. The observed Doppler shift, which is commonly called speed-of-light perturbation, can be well described by the relativistic Doppler formula, where the constant object velocity is replaced by a time-dependent velocity with constant acceleration. The observed speed-of-light perturbation stands in contrast to other publications, which predict a higher frequency shift. It has been measured with a relative uncertainty of 1.1 × 10 −3

Seismic-frequency attenuation and moduli estimates using a fiber-optic strainmeter

Summary We have developed a fiber-optic strainmeter to estimate velocities and attenuation at seismic frequencies. The two main advantages of the new system compared to strain gage techniques are the higher sensitivity to deformations (moduli) and phase lags (attenuation), and that estimates are representative of bulk values. While stress-strain measurements using strain gages or ultrasonic wave propagation sample only part of the core sample, the fiber-optic strainmeter would analyze the rock sample response to an applied stress as a whole. Still, the system is under development and the first experiment on a Plexiglas sample showed that attenuation estimates are more robust than deformation estimates due to difficulties with light intensity. Initial rock measurements are made on a dolomite sample

Changes in absolute gravity 2000–2015, South Island, New Zealand

<p>We quantify changes in gravity that have occurred over the past 15 years at 14 points between latitudes 42.5°S and 44°S in the South Island of New Zealand. Ten of the points form two transects across the Southern Alps and four lie in the epicentral region of the 2010 Canterbury earthquakes. At each location gravity was measured using an absolute gravimeter (FG5–111) with a nominal accuracy of 1 µGal. Observed changes in gravity varied from −53 to +43 µGal in the presence of surface elevation changes in the range −11 cm to +20 cm. Despite the difficulty in quantifying gravitational contributions from surface and subsurface water, uplift in both the Southern Alps and the Christchurch region is consistent with a Bouguer surface gradient of approximately 1.97 µGal cm^–1, appropriate for the mean density of crustal rocks.</p

Creighton University Window Summer 1988

CAMPUS / THE CAMPUS OF 1988: CHANGES LIKE THE 60S Not for some 20 years have there been so many changes to the face of the Creighton campus. Aerial photos, maps, the whole story starts on Page 4. SO GREAT WAS THE STRUGGLE 1879 / BUT BACK IN 1878 THERE WAS A STRUGGLE TO BEGIN Fr. Roland Reichmuth gives readers the first taste of his book on Creighton and its "heroic" struggle to survive in 1878. Page 12. THE 5TH FORCE / 5TH FORCE: ADVENTURE IN SCIENTIFIC RESEARCH Creighton physics graduate Dr. Tim Niebauer takes you into the world of pure research and the mystery of the Fifth Force. Page 16. THE CREIGHTON CENTER FOR HEALTHY AGING / THE NEW CREIGHTON CENTER FOR HEALTHY AGING Dr. David Haber tells what's new at one of Creighton's newest ventures in behalf of the older citizen — the Center for Healthy Aging. Page 20.4

Incidence of complications associated with tibial tuberosity advancement in Boxer dogs

Objective: To retrospectively review and describe the incidence of complications associated with tibial tuberosity advancement (TTA) surgical procedures in a group of Boxer dogs (n = 36 stifles) and compare the data with a non-Boxer control population (n = 271 stifles). Methods: Retrospective analysis of medical records to identify all dogs that underwent TTA surgery due to cranial cruciate ligament disease. These records were categorized into two groups: Boxer dogs and non-Boxer dogs (controls – all other breeds). Results: Of the 307 stifles included, 69 complications were reported in 58 joints. The complication rate differed significantly for Boxer dogs (16/36 stifles) and non-Boxer dogs (42/271 stifles), corresponding to an odds ratio of 5.8 (confidence interval: 1.96–17.02; p-value &#60;0.001). Boxer dogs were more likely to undergo revision surgery and to develop multiple complications. The incidence of tibial tuberosity fractures requiring surgical repair (2/36 versus 1/271) and incisional infections requiring antibiotic treatment (three in each group) was significantly higher in the Boxer group. Clinical significance: Boxer dogs had more major and multiple complications after TTA surgery than the control non-Boxer group; these complications included higher rates of revision surgery, tibial tuberosity fractures requiring stabilization, and infection related complications. The pertinence and value of breed-specific recommendations for cranial cruciate ligament disease appears to be a subject worthy of further investigation