Geodetic measurements at sea floor spreading centers

A network of 8 or more precision transponder units mounted on the sea floor and interrogated periodically from an instrument package towed near bottom through the area to provide the necessary spatial averaging could provide a practical system for observing the pattern of buildup of strain at intermediate and fast spreading centers

Acceleration measurements in the deep ocean

The study of surface waves in the deep ocean can be carried out effectively by using a new technique: measurement of accelerations of a small water mass well below the surface. Instrumentation for carrying out such measurements is described in detail, including a special accelerometer, neutrally buoyant case, long lightweight slack wire, and data-recording equipment. Some initial results achieved with this equipment are shown and the possibility of broader applications of this technique for wave and gravity measurements at sea are discussed briefly

Near-bottom seismic profiling: High lateral variability, anomalous amplitudes, and estimates of attenuation

For almost a decade the Marine Physical Laboratory of Scripps Institution of Oceanography has been conducting near‐bottom geophysical surveys involving quantitative seismic profiling. Operating initially at 4 kHz and more recently at 6 kHz, this system has provided a wealth of fine scale quantitative data on the acoustic properties of ocean sediments. Over lateral distances of a few meters, 7‐dB changes in overall reflected energy as well as 10‐dB changes from individual reflectors have been observed. Anomalously high amplitudes from deep reflectors have been commonly observed, suggesting that multilayer interference is prevalent in records from such pulsed cw profilers. This conclusion is supported by results from sediment core physical property work and related convolution modeling, as well as by the significant differences observed between 4‐ and 6‐kHz profiles. In general, however, lateral consistency has been adequate in most areas surveyed to permit good estimates of acoustic attenuation from returns from dipping reflectors and sediment wedges

Analysis of a method for precisely relating a seafloor point to a distant point on land

A study of the environmental constraints and engineering aspects of the acoustic portion of a system for making geodetic ties between undersea reference points and others on land is described. Important areas in which to make such observations initially would be from the California mainland out to oceanic points seaward of the San Andreas fault, and across the Aleutian Trench. The overall approach would be to operate a GPS receiver in a relative positioning (interferometric) mode to provide the long range element of the baseline determination (10 to 1,000 km) and an array of precision sea floor acoustic transponders to link the locally moving sea surface GPS antenna location to a fixed sea floor point. Analyses of various environmental constrants (tides, waves, currents, sound velocity variations) lead to the conclusion that, if one uses a properly designed transponder having a remotely controllable precise retransmission time delay, and is careful with regard to methods for installing these on the sea floor, one should, in many ocean locations, be able to achieve sub-decimeter overall system accuracy. Achievements of cm accuracy or better will require additional understanding of time and space scales of variation of sound velocity structure in the ocean at relevant locations

Corneal collagen cross-linking as treatment for infectious and non-infectious corneal melting in cats and dogs: results of a prospective, non-randomized, controlled trial

OBJECTIVE. UV-A/Riboflavin crosslinking of corneal collagen fibers (CXL) is a highly promising therapy for corneal melting in humans. A prospective interventional, non-randomized, controlled study was conducted to compare the stabilizing effect of CXL treatment on melting keratitis in dogs and cats and the complication rate of CXL to those of standardized intensive medical treatment. PROCEDURES. Forty-nine eyes with melting keratitis were included in the study between October 2009 and October 2012. All eyes were treated according to the same medical treatment protocol. Nineteen eyes were CXL-treated and 30 eyes were not. Follow-up included slit-lamp examination, fluorescein staining, ulcer size measurement, stromal stability evaluation, photographic documentation and documentation of complications. RESULTS. Five of 19 eyes in the CXL group and 9/30 eyes in the control group required rescue stabilization due to continued melting. Seven of the 9 control group corneas stabilized after rescue CXL treatment. At initial presentation, the ulcers in the canine CXL group were significantly deeper and larger than in the control group. Ulcer deepening during follow-up was more pronounced in the canine control group than in the canine CXL group. CXL treatment related complications were not observed. CONCLUSIONS. Based on the similar failure rates in the control and CXL treatment groups despite the poorer initial situation in the CXL group, the tendency for the ulcers in the control group to deepen and the stabilization of all corneas receiving CXL rescue treatment, we believe that CXL has its place as an adjunctive therapy for melting keratitis in veterinary ophthalmology

Advances in the process-related understanding of atmosphere-cryosphere-hydrosphere couplings on the Tibetan Plateau

Abstract HKT-ISTP 2013 B

Early hemostatic responses to trauma identified with hierarchical clustering analysis

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111900/1/jth12919.pd

Growing Correlation Length on Cooling Below the Onset of Caging in a Simulated Glass-Forming Liquid

We present a calculation of a fourth-order, time-dependent density correlation function that measures higher-order spatiotemporall correlations of the density of a liquid. From molecular dynamics simulations of a glass-forming Lennard-Jones liquid, we find that the characteristic length scale of this function has a maximum as a function of time which increases steadily beyond the characteristic length of the static pair correlation function $g(r)$ in the temperature range approaching the mode coupling temperature from above