A steepest descent calculation of RNA pseudoknots

We enumerate possible topologies of pseudoknots in single-stranded RNA molecules. We use a steepest-descent approximation in the large N matrix field theory, and a Feynman diagram formalism to describe the resulting pseudoknot structure

Observations of current rings in the Antarctic Zone at Drake Passage

Time series of current velocity and temperature from several depths at a site near the center of Drake Passage show features that can plausibly be interpreted as current rings. Between June 1975 and January 1976, five cyclonic rings from the Continental Water Boundary and one anticyclonic ring from the Polar Front passed over the site. The diameters of the rings varied from 30 km to 130 km, and all of them extended vertically to a depth of at least 2500 m. The rings exhibited maximum spin velocities of about 20 cm sec−1 at 1000 m depth and 10 cm sec−1 at 2500 m. Their translatory motion, which was toward the north at about 4 cm sec−1, contained a westward component relative to the ambient flow. The magnitude of the westward component suggests that it may have resulted from an interaction between rings and the sea floor, which slopes downward to the northeast at the mooring site. The total available mechanical energy of the rings (kinetic plus potential) varied from 6.2 × 1013 j in the smallest ring to 9.9 × 1014 in the largest. The available heat, relative to the Antarctic Zone, was several orders of magnitude larger: −3.0 × 1017 j for the smallest ring and −3.6 × 1018 j for the largest. The numbers indicate that current rings may play an important role in dissipating the kinetic energy of the circumpolar fronts and that they may be responsible for a significant poleward flux of heat in the Southern Ocean

A compilation of observations from moored current meters. Vol. VIII. Wind, currents and temperature off Northwest Africa along 21°40' N during JOINT-1

Current meters, moored during JOINT-I in the coastal upwelling area off Northwest Africa along 21°40'N measured current speed and direction, temperature and, in some cases, conductivity and pressure. In addition, surface buoy meterological stations were installed at some current meter strings to record wind speed and direction, as well as air and water temperature. The sampling intervals of the instruments were 5 and 10 minutes. The data have been filtered and are shown here by means of pertinent statistics, real time plots, progressive vector diagrams and rotary spectra of hourly values

A Compilation of observations from moored current meters. Vol. VII. Oregon continental shelf, July-August 1973

Aanderaa recording current meters, moored off the Oregon coast at fixed depths measured water temperature, current speed, current direction and for some meters, conductivity and pressure. In addition to these sub­surface meters, surface meteorological buoys were installed to measure wind speed, wind direction, air and water temperature. Data from each current meter string are shown by means of pertinent statistics, real time plots of hourly values, progressive vector diagrams, and rotary spectra

A compilation of observations from moored current meters. Vol. 12. Currents, temperature and pressure in the Drake Passage during FDRAKE 77, 78, January 1977-January 1979

Internally recording instruments were installed in the Drake Passage in January 1977 and recovered in December 1977. Additional instruments were installed at this time and recovered in January 1979. The first array consisted of 21 Aanderaa current meters on five moorings. The second array was one mooring with three current meters. The data were taken at one hour intervals. In this report the measurements are summarized through pertinent statistics, progressive vector diagrams, real time plots, stick figures, rotary spectra, and conventional power spectra

A Compilation of observations from moored current meters. Vol. 6. Oregon continental shelf, April-October 1972

Aanderaa recording current meters, moored in CUE-I off the Oregon coast at specific depths along both the Newport hydrographic line and perpendicular to the isobaths off Depoe Bay, were set to measure water temperature, current speed, current direction and, in some cases, pressure. In addition, surface buoy meteorological stations were moored at points along these same lines to measure wind speed, direction and air and water temperature. Data from each current meter string are shown by means of pertinent statistics, real time plots of hourly values, progressive vector diagrams and rotary spectra. The appendices describe the actual operation of the Aanderaa current meter and the methods used to process the data

Effects of tidal-forcing variations on tidal properties along a narrow convergent estuary

A 1D analytical framework is implemented in a narrow convergent estuary that is 78 km in length (the Guadiana, Southern Iberia) to evaluate the tidal dynamics along the channel, including the effects of neap-spring amplitude variations at the mouth. The close match between the observations (damping from the mouth to ∼ 30 km, shoaling upstream) and outputs from semi-closed channel solutions indicates that the M2 tide is reflected at the estuary head. The model is used to determine the contribution of reflection to the dynamics of the propagating wave. This contribution is mainly confined to the upper one third of the estuary. The relatively constant mean wave height along the channel (< 10% variations) partly results from reflection effects that also modify significantly the wave celerity and the phase difference between tidal velocity and elevation (contradicting the definition of an “ideal” estuary). Furthermore, from the mouth to ∼ 50 km, the variable friction experienced by the incident wave at neap and spring tides produces wave shoaling and damping, respectively. As a result, the wave celerity is largest at neap tide along this lower reach, although the mean water level is highest in spring. Overall, the presented analytical framework is useful for describing the main tidal properties along estuaries considering various forcings (amplitude, period) at the estuary mouth and the proposed method could be applicable to other estuaries with small tidal amplitude to depth ratio and negligible river discharge.info:eu-repo/semantics/publishedVersio