Scales of motion in the deep Gulf Stream and across the Continental Rise

An array of 15 moorings with 33 current meters was deployed in the deep water across the Continental Rise near 70°W for eight months. The data thus obtained provide the first synoptic view of the large amplitude, long period variability associated with the deep Gulf Stream region, shown here to have meridional scales of 150 km but zonal scales of less than 50 km. These fluctuations are associated with temperature variation of 0.5°C and exhibit a southward phase propagation of 10 cm/sec

Equatorial current measurements, I. Moored observations

The low frequency fluctuations in the western Indian Ocean are dominated by energetic variability with relatively small horizontal and vertical scales. The time series of horizontal current and temperature exhibit a number of energetic events which, for the most part, are not sufficiently resolved to assign a spatial scale to the underlying process...

Exploring the North Atlantic Ocean on floppy disks

Data from four floppy disks found in the zip fileA selection of hydrographic station data in the Atlantic between 8°S and 70°N is packed on four 5 1/4" floppy disks. Sample utility programs for reading and plotting the data are also on the disks. We present this computer atlas in preliminary form for use by students and professionals, in the belief that easy access to this valuable historical data will be educational and stimulating.Funding was provided by the Office of Naval Research under contract Number N00014-84-C-0134, and the National Science Foundation through grant Number OCE86-13810

Spectral time scales for mid-latitude eddies

A few hundred current meter records of roughly one to two years\u27 duration are now available from diverse locations in the world\u27s oceans, primarily the North Atlantic. The shape of the spectrum for low-frequency ocean current fluctuations is shown to have a geographical distribution related to the general circulation. In the offshore segment of the Gulf Stream and Kuroshio Extension systems along with their recirculations, and near the Agulhas Current as well, normalized frequency distributions of eddy kinetic energy tend to be comparatively depth-independent and peaked at the mesoscale. However, in the immediate vicinity of current axes or fronts, spectral shapes may become “red” in the thermocline, as a result of low-frequency meandering of a baroclinic jet across mooring sites. Normalized frequency distributions of eddy kinetic energy from some areas distant from strong currents but perhaps near weaker upper-ocean fronts tend to be baroclinic and not peaked at the mesoscale in the thermocline, rather they are “red” there, although peaked at the mesoscale at abyssal depths. There are also low energy regions where spectral shapes tend to be red and comparatively independent of depth. In some areas, frequency distributions are relatively energetic or peaked at periods of order days, normally at depth near bottom relief

Moored velocity measurements on the edge of the Gulf-Stream recirculation

Mean velocities, eddy kinetic energies and time series of velocities at several depths are presented from moored current meters for the 15 month period May 1978 to July 1979 as part of the POLYMODE Local Dynamics Experiment, centered at 31N, 69°30\u27W. The mean velocities in the upper one kilometer are toward the southwest at 2.4 to 4.4 cm/s, consistent with Worthington\u27s (1976) description of the mean circulation of the North Atlantic...

Subduction in the subtropical gyre : Seasoar cruises data report

The overall objective of the Subduction Accelerated Research Initiative (ARI) was to bring together several techniques to address the formation and evolution of newly formed water masses. The Seasoar component provided surveys of temperature and salinity to help determine the spatial varability of the temperature, salinity and density fields in both the active frontal regions and in the vicinity of subducting water tagged by bobbers. Data were collected in the eastern North Atlantic Ocean in spring 1991, winter 1992, winter 1993 and spring 1994. "Star" patterns were used to study the mesoscale varability. Temperature, pressure and thickness for each pattern were objectively mapped on potential density surfaces of 26.5, 26.7 and 26.9 kg/m3. Acoustic Doppler Current Profies (ADCP) maps were also created for the the two shallower density surfaces. We describe the Seasoar data collected during the four cruises. A CD-Rom includes 1- and 3-second conductivity-temperature-depth (CTD), cruise navigation, ADCP and Seasoar engineering data, as well as color figures of these data. This data report can also be viewed using an internet information browser (i.e., Mosaic, Netscape) using the provided CD-Rom.Funding was provided by the Office of Naval Research through Grants Nos, N00014-91-J-1585, N00014-90-J-1425. and N00014-90-J-1508

Moored current meter, AVHRR, CTD, and drifter data from the Agulhas Current and Retroflexion region (1985-1987) Volume XLII

Stored in the Archives of the Woods Hole Oceanographic Institution is the floppy disk on which can be found the one-day average currents, the path of the Agulhas Current, CTD stations in "Live Atlas" format, SST frontal analyses (Chassignet and Olson, personal communcation) as well as programs written in QuickBASIC which allow one to access and display these observations. The programs are stored in ASCII and can be run under the Microsoft QuickBasic (Version 4.0 or higher). Instructions for running the programs can be found in a file entitled "read.me" on the disk.Data are presented from an experiment designed to explore the spatial and temporal structure of the Agulhas Current and Retroflexion by direct means. Included are the current meter results from 10 moorings in the Retroflexion region, CTD stations occupied on the deployment cruise in 1985, data from satellite tracked (ARGOS) freely during surface buoys and numerous images of the sea surface temperature.Funding was provided by the Office of Naval Research through Contract Nos. NOOO14-84C-O134, NOO014-85-C-0001, and NOOO14-87-K-0007

Tomographic Separation of Composite Spectra. VIII. The Physical Properties of the Massive Compact Binary in the Triple Star System HD 36486 (delta Orionis A)

Double-lined spectroscopic orbital elements have recently been found for the central binary in the massive triple, delta Orionis A based on radial velocities from cross-correlation techniques applied to IUE high dispersion spectra and He I 6678 spectra obtained at Kitt Peak. The primary and secondary velocity amplitudes were found to be 94.9 +/- 0.6 km/s and 186 +/- 9 km/s respectively. Tomographic reconstructions of the primary and secondary stars' spectra confirm the O9.5 II classification of the primary and indicate a B0.5 III type for the secondary. The widths of the UV cross-correlation functions are used to estimate the projected rotational velocities, Vsin i = 157 +/- 6 km/s and 138 +/- 16 km/s for the primary and secondary, respectively implying that both stars rotate faster than their orbital motion. We used the spectroscopic results to make a constrained fit of the Hipparcos light curve of this eclipsing binary, and the model fits limit the inclination to the range between 67 and 77 degrees. The i = 67 degrees solution, which corresponds to a near Roche-filling configuration, results in a primary mass of 11.2 solar masses and a secondary mass of 5.6 solar masses, both of which are substantially below the expected masses for stars of their luminosity. This binary may have experienced a mass ratio reversal caused by Case A Roche lobe overflow, or the system may have suffered extensive mass loss through a binary interaction, perhaps during a common envelope phase, in which most of the primary's mass was lost from the system rather than transferred to the secondary.Comment: 27 pages, 15 figures in press, the Astrophysical Journal, February 1, 200

Cost and disease burden of Dengue in Cambodia

<p>Abstract</p> <p>Background</p> <p>Dengue is endemic in Cambodia (pop. estimates 14.4 million), a country with poor health and economic indicators. Disease burden estimates help decision makers in setting priorities. Using recent estimates of dengue incidence in Cambodia, we estimated the cost of dengue and its burden using disability adjusted life years (DALYs).</p> <p>Methods</p> <p>Recent population-based cohort data were used to calculate direct and productive costs, and DALYs. Health seeking behaviors were taken into account in cost estimates. Specific age group incidence estimates were used in DALYs calculation.</p> <p>Results</p> <p>The mean cost per dengue case varied from US$36 -$75 over 2006-2008 respectively, resulting in an overall annual cost from US$3,327,284 in 2008 to US$14,429,513 during a large epidemic in 2007. Patients sustain the highest share of costs by paying an average of 78% of total costs and 63% of direct medical costs. DALY rates per 100,000 individuals ranged from 24.3 to 100.6 in 2007-2008 with 80% on average due to premature mortality.</p> <p>Conclusion</p> <p>Our analysis confirmed the high societal and individual family burden of dengue. Total costs represented between 0.03 and 0.17% of Gross Domestic Product. Health seeking behavior has a major impact on costs. The more accurate estimate used in this study will better allow decision makers to account for dengue costs particularly among the poor when balancing the benefits of introducing a potentially effective dengue vaccine.</p

The Milky Way Tomography with SDSS: I. Stellar Number Density Distribution

Abridged: We estimate the distances to ~48 million stars detected by the Sloan Digital Sky Survey and map their 3D number density distribution in 100 < D < 20 kpc range over 6,500 deg^2 of sky. The data show strong evidence for a Galaxy consisting of an oblate halo, a disk component, and a number of localized overdensities with exponential disk parameters (bias-corrected for an assumed 35% binary fraction) H_1 = 300 pc, L_1 = 2600 pc, H_2 = 900 pc, L_2 = 3600 pc, and local density normalization of 12%. We find the halo to be oblate, with best-fit axis ratio c/a = 0.64, r^{-2.8} profile, and the local halo-to-thin disk normalization of 0.5%. We estimate the errors of derived model parameters to be no larger than ~20% (disk scales) and ~10% (thick disk normalization). While generally consistent with the above model, the density distribution shows a number of statistically significant localized deviations. We detect two overdensities in the thick disk region at (R, Z) ~ (6.5, 1.5)kpc and (R, Z) ~ (9.5, 0.8) kpc, and a remarkable density enhancement in the halo covering >1000deg^2 of sky towards the constellation of Virgo, at distances of ~6-20 kpc. Compared to a region symmetric with respect to the l=0 line, the Virgo overdensity is responsible for a factor of 2 number density excess and may be a nearby tidal stream or a low-surface brightness dwarf galaxy merging with the Milky Way. After removal of the resolved overdensities, the remaining data are consistent with a smooth density distribution; we detect no evidence of further unresolved clumpy substructure at scales ranging from ~50pc in the disk, to ~1 - 2 kpc in the halo.Comment: 60 pages, 46 figures (reduced resolution; see the ApJ for hi-res version