147 research outputs found
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California cooperative oceanic fisheries investigations. Reports volume 37, January 1--December 31, 1995
Scientists from the California Department of Fish and Game (CDFG), the Southwest Fisheries Science Center of the National Marine Fisheries Service (NMFS), and the Scripps Institution of Oceanography, University of California, San Diego (UCSD), have collaborated for 46 years in the longest-running large-scale study ever undertaken in the ocean. This study was begun in order to understand the causes of changes in population, over time, of commercially important fishes in California`s coastal waters. When the study began, the Pacific sardine was by far the most significant species of economic concern to the State of California. Because its population changes were thought to be caused by a diversity of atmospheric, oceanic, and biological variables, a wide array of measurements in the California Current region were begun and have been continued to this day. This long time series of data allows not only a better understanding of the flux of fish populations, but also lays the foundation for understanding interdecadal and secular change in the seas. This document contains papers from symposium of the 1995 CalCOFI Conference related to interdecadal changes in the ecology of the California current
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Biofouling Effects on the Response of a Wave Measurement Buoy in Deep Water
Different stress-related phenotypes of BALB/c mice from in-house or vendor: alterations of the sympathetic and HPA axis responsiveness
<p>Abstract</p> <p>Background</p> <p>Laboratory routine procedures such as handling, injection, gavage or transportation are stressful events which may influence physiological parameters of laboratory animals and may interfere with the interpretation of the experimental results. Here, we investigated if female BALB/c mice derived from in-house breeding and BALB/c mice from a vendor which were shipped during their juvenile life differ in their HPA axis activity and stress responsiveness in adulthood.</p> <p>Results</p> <p>We show that already transferring the home cage to another room is a stressful event which causes an increased HPA axis activation for at least 24 hours as well as a loss of circulating lymphocytes which normalizes during a few days after transportation. However and important for the interpretation of experimental data, commercially available strain-, age- and gender-matched animals that were shipped over-night showed elevated glucocorticoid levels for up to three weeks after shipment, indicating a heightened HPA axis activation and they gained less body weight during adolescence. Four weeks after shipment, these vendor-derived mice showed increased corticosterone levels at 45-min after intraperitoneal ACTH challenge but, unexpectedly, no acute stress-induced glucocorticoid release. Surprisingly, activation of monoaminergic pathways were identified to inhibit the central nervous HPA axis activation in the vendor-derived, shipped animals since depletion of monoamines by reserpine treatment could restore the stress-induced HPA axis response during acute stress.</p> <p>Conclusions</p> <p>In-house bred and vendor-derived BALB/c mice show a different stress-induced HPA axis response in adulthood which seems to be associated with different central monoaminergic pathway activity. The stress of shipment itself and/or differences in raising conditions, therefore, can cause the development of different stress response phenotypes which needs to be taken into account when interpreting experimental data.</p
The California coastal wave monitoring and prediction system
AbstractA decade-long effort to estimate nearshore (20m depth) wave conditions based on offshore buoy observations along the California coast is described. Offshore, deep water directional wave buoys are used to initialize a non-stationary, linear, spectral refraction wave model. Model hindcasts of spectral parameters commonly used in nearshore process studies and engineering design are validated against nearshore buoy observations seaward of the surfzone. The buoy-driven wave model shows significant skill at most validation sites, but prediction errors for individual swell or sea events can be large. Model skill is high in north San Diego County, and low in the Santa Barbara Channel and along the southern Monterey Bay coast. Overall, the buoy-driven model hindcasts have relatively low bias and therefore are best suited for quantifying mean (e.g. monthly or annual) nearshore wave climate conditions rather than extreme or individual wave events. Model error correlation with the incident offshore wave energy, and between neighboring validation sites, may be useful in identifying sources of regional modeling errors
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Sixteen years of bathymetry and waves at San Diego beaches.
Sustained, quantitative observations of nearshore waves and sand levels are essential for testing beach evolution models, but comprehensive datasets are relatively rare. We document beach profiles and concurrent waves monitored at three southern California beaches during 2001-2016. The beaches include offshore reefs, lagoon mouths, hard substrates, and cobble and sandy (medium-grained) sediments. The data span two energetic El Niño winters and four beach nourishments. Quarterly surveys of 165 total cross-shore transects (all sites) at 100âm alongshore spacing were made from the backbeach to 8âm depth. Monthly surveys of the subaerial beach were obtained at alongshore-oriented transects. The resulting dataset consists of (1) raw sand elevation data, (2) gridded elevations, (3) interpolated elevation maps with error estimates, (4) beach widths, subaerial and total sand volumes, (5) locations of hard substrate and beach nourishments, (6) water levels from a NOAA tide gauge (7) wave conditions from a buoy-driven regional wave model, and (8) time periods and reaches with alongshore uniform bathymetry, suitable for testing 1-dimensional beach profile change models
Lay perceptions of Carbon Dioxide Utilisation technologies in the United Kingdom and Germany: An exploratory qualitative interview study
Carbon Dioxide Utilisation (CDU) technologies convert Carbon Dioxide (CO2) into carbon-based products. CDU technologies are viewed as a means of helping to address climate change while creating commodities that can be sold to generate financial revenue. While technical research and development into CDU options is accelerating, at present there has been little research into public acceptance of the technology. The current study presents the findings of a series of 28 exploratory interviews conducted with lay people in the United Kingdom and Germany. The results show that awareness of CDU is currently very low in both countries but that there is tentative support for the concept. This support is, however, caveated by considerations of the techno-economic feasibility of the technology and the societal consequences that might result from investment. While the thematic content of discussions was similar in both countries, where appropriate any notable differences are outlined and discussed. In addition to providing fresh insight into the emerging nature of public perceptions and acceptance of CDU, it is reasoned that the findings of this research could help to benefit the design of communication materials intended to engage lay-publics in debate about the nature and purpose of CDU technologie
Attitude control research with educational nanosatellites
This paper introduces the three-axis attitude control of the ESAT platform. ESAT is a modular nanosatellite that implements the popular 10x10x10 cm CubeSat standard, designed for hands-on learning at different educational levels as well as professional training. ESAT features the full set of characteristic spacecraft subsystems (power, on-board data handling, attitude control, communications, and payload). The satellite can be disassembled to focus on each subsystem, one at a time, or used all together, and features a flexible ground segment. Courses using the ESAT platform are imparted in our university, as part of the last year of the masterâs degree in Aerospace engineering, and in other institutions like the ESA Academy. They cover aspects ranging from subsystems design to testing and spacecraft operations. In addition, the platform is used in masterâs thesis and research activities. Although the version that is currently being used in the courses allows only one-axis attitude control, the ESAT is in continuous development and two prototypes of the satellite have already been developed that allow three-axis control based on reaction wheels and/or magnetorquers, which is essential for the testing and verification of attitude determination and control algorithms. For this purpose, the ground support equipment has also been updated to be able to carry out the turns in three axes, with the development of new testbeds and a complete magnetic field simulator. The present work aims to show the new three-axis platform designs and its main functionalitie
Relations between molecular gas absoptivities and emissivities
Theoretical expressions have been derived for the relations
between gas absorptivities and emissivities for
the limit of zero optical depth and for the following
models of vibration-rotation bands: bands with constant
average absorption coefficients and well-defined widths;
just-overlapping spectral lines; non-overlapping dispersion
lines with constant collision half-width and either
regular line spacing or with lines of equal intensity;
randomly distributed spectral lines with dispersion contom;
non-overlapping Doppler lines with either regular
line spacing or with lines of equal intensity; randomly
distributed Doppler lines for a special {unrealistic} assumption
relating to the temperature dependence of the
effective mean line spacing; non-overlapping spectral
lines with combined Doppler and collision broadening,
constant collision half-width and either regular line
spacing or with lines of equal intensity. The theoretical
formulae have been shown to provide a good correlation
for the available experimental data on CO_2, H_2O and CO
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