Composite infrared spectrometer (CIRS) on Cassini.

The Cassini spacecraft orbiting Saturn carries the composite infrared spectrometer (CIRS) designed to study thermal emission from Saturn and its rings and moons. CIRS, a Fourier transform spectrometer, is an indispensable part of the payload providing unique measurements and important synergies with the other instruments. It takes full advantage of Cassini's 13-year-long mission and surpasses the capabilities of previous spectrometers on Voyager 1 and 2. The instrument, consisting of two interferometers sharing a telescope and a scan mechanism, covers over a factor of 100 in wavelength in the mid and far infrared. It is used to study temperature, composition, structure, and dynamics of the atmospheres of Jupiter, Saturn, and Titan, the rings of Saturn, and surfaces of the icy moons. CIRS has returned a large volume of scientific results, the culmination of over 30 years of instrument development, operation, data calibration, and analysis. As Cassini and CIRS reach the end of their mission in 2017, we expect that archived spectra will be used by scientists for many years to come.

Composite infrared spectrometer (CIRS) on Cassini: publisher's note.

This publisher's note renumbers the reference list in Appl. Opt.56, 5274 (2017)APOPAI0003-693510.1364/AO.56.005274.

An intense stratospheric jet on Jupiter.

The Earth's equatorial stratosphere shows oscillations in which the east-west winds reverse direction and the temperatures change cyclically with a period of about two years. This phenomenon, called the quasi-biennial oscillation, also affects the dynamics of the mid- and high-latitude stratosphere and weather in the lower atmosphere. Ground-based observations have suggested that similar temperature oscillations (with a 4-5-yr cycle) occur on Jupiter, but these data suffer from poor vertical resolution and Jupiter's stratospheric wind velocities have not yet been determined. Here we report maps of temperatures and winds with high spatial resolution, obtained from spacecraft measurements of infrared spectra of Jupiter's stratosphere. We find an intense, high-altitude equatorial jet with a speed of approximately 140 m s(-1), whose spatial structure resembles that of a quasi-quadrennial oscillation. Wave activity in the stratosphere also appears analogous to that occurring on Earth. A strong interaction between Jupiter and its plasma environment produces hot spots in its upper atmosphere and stratosphere near its poles, and the temperature maps define the penetration of the hot spots into the stratosphere.

Cassini encounters Enceladus: background and the discovery of a south polar hot spot.

The Cassini spacecraft completed three close flybys of Saturn's enigmatic moon Enceladus between February and July 2005. On the third and closest flyby, on 14 July 2005, multiple Cassini instruments detected evidence for ongoing endogenic activity in a region centered on Enceladus' south pole. The polar region is the source of a plume of gas and dust, which probably emanates from prominent warm troughs seen on the surface. Cassini's Composite Infrared Spectrometer (CIRS) detected 3 to 7 gigawatts of thermal emission from the south polar troughs at temperatures up to 145 kelvin or higher, making Enceladus only the third known solid planetary body-after Earth and Io-that is sufficiently geologically active for its internal heat to be detected by remote sensing. If the plume is generated by the sublimation of water ice and if the sublimation source is visible to CIRS, then sublimation temperatures of at least 180 kelvin are required.

Titan's atmospheric temperatures, winds, and composition.

Temperatures obtained from early Cassini infrared observations of Titan show a stratopause at an altitude of 310 kilometers (and 186 kelvin at 15 degrees S). Stratospheric temperatures are coldest in the winter northern hemisphere, with zonal winds reaching 160 meters per second. The concentrations of several stratospheric organic compounds are enhanced at mid- and high northern latitudes, and the strong zonal winds may inhibit mixing between these latitudes and the rest of Titan. Above the south pole, temperatures in the stratosphere are 4 to 5 kelvin cooler than at the equator. The stratospheric mole fractions of methane and carbon monoxide are (1.6 +/- 0.5) x 10(-2) and (4.5 +/- 1.5) x 10(-5), respectively.

Temperatures, winds, and composition in the saturnian system.

Stratospheric temperatures on Saturn imply a strong decay of the equatorial winds with altitude. If the decrease in winds reported from recent Hubble Space Telescope images is not a temporal change, then the features tracked must have been at least 130 kilometers higher than in earlier studies. Saturn's south polar stratosphere is warmer than predicted from simple radiative models. The C/H ratio on Saturn is seven times solar, twice Jupiter's. Saturn's ring temperatures have radial variations down to the smallest scale resolved (100 kilometers). Diurnal surface temperature variations on Phoebe suggest a more porous regolith than on the jovian satellites.

Biologically active luteinizing hormone (LH) in plasma: II. Comparison with immunologically active LH levels throughout the human menstrual cycle.

The levels of biologically active luteinizing hormone were determined by an in vitro bioassay method in plasma samples collected daily over a complete menstrual cycle from 12 menstruating women. These cycles were normal according to a number of criteria, including daily plasma levels of oestradiol, 17-hydroxyprogesterone and progesterone. Immunoreactive LH was estimated in the same 12 cycles by a radio-immunoassay (RIA) procedure (HCG-RIA) using an HCG antiserum and iodinated HCG. The 2nd IRP of HMG was selected as standard although significant deviations from parallelism were found with 7 out of the 12 plasma pools studied. The use of the 1st IRP of human pituitary gonadotrophins (FSH and LH (ICSH)) for bioassay (herafter HPG-1st IRP) as standard in this system resulted invariably in invalid assays, due to lack of parallelism. Immunoreactive LH was also measured in 8 of the 12 cycles by a RIA procedure (HLA-RIA) using a human LH antiserum and iodinated human LH of pituitary origin. Results are expressed in terms of the HPG-1st IRP. The plasma levels of biologically and immunologically active LH were qualitatively similar throughout the menstrual cycle. However, the LH levels measured by the bioassay invariably exceeded those estimated by the RIA procedures. The biological to immunological (B/I) ratio over the entire menstrual cycle (312 comparisons) was 5.5 with 95% confidence limits at 5.2 and 5.8 when the HCG-RIA system was employed. Using the HLH-RIA system (208 comparisons), the corresponding ratio was 6.4 (6.0:6.9). When regression lines were calculated using the bioassay results as the independent variable and the RIA results as the dependent variable, the 95% confidence limits of the regression lines did not include the origin. Furthermore,, in keeping with the high B/I ratios, the slopes of the two regression lines and their conficence limits differed markedly from unity. It is concluded that although qualitatively similar profiles were observed between the biological and immunological activities throughtout the menstrual cycle, two aspects require further attention. Firstly, the elevated B/I ratios together with the behaviour of the dose-effect lines obtained with different standards in the various RIA systems suggest that presently available reference standard preparations of pituitary and/or urinary origin are not suitable for the assay of LH in human plasms. Secondly, from the regression analyses of the biological and immunological activities it is infered that the RIA methods detect immunological activity which is not associated with biological activity. If so, the validity of these RIA procedures for specifically measuring low levels of biologically active LH in plasma may be in question.

Polyamine macrocycles incorporating a phenolic function: their synthesis, basicity, and coordination behavior toward metal cations. Crystal structure of a binuclear nickel complex.

The synthesis and characterization of two new polyazamacrocycles, 1,4,7,10-tetraaza[12](2,6)phenolphane (L1) and 1,4,7,10,13-pentaaza[15](2,6)phenolphane (L2), are reported. Both ligands incorporate the 2,6-phenolic unit within the cyclic framework. The basicity behavior and the ligational properties of L1 and L2 toward Ni(II), Zn(II), and Cu(II) were determined by means of potentiometric measurements in aqueous solution (298.1 +/- 0.1 K, I = 0.15 mol dm-3). UV spectra were used to understand the role of the phenolic function in the stabilization of the cations. L1 and L2 behave as pentaprotic bases under the experimental conditions used. The UV spectra showed that the deprotonation of the phenolic function occurs at low pH values for both ligands, giving rise to the simultaneous presence of positive and (one) negative charges on the macrocycle. While L1 forms only mononuclear complexes, L2 can also form binuclear species with all the metal ions investigated. In the mononuclear species of both ligands, one nitrogen atom close to the phenol remains unbound. The UV spectra revealed that the phenol, bridging the two metal ions in phenolate form, plays an important role in the stabilization of the binuclear complexes of L2. The coordination sphere of the two metals is completed by adding a secondary ligand such as water molecules or OH-, in any case preferring substrates able to bridge the two close metal ions. These results are confirmed by the crystal structure of [Ni2(C16H28ON5)(H2O)2Cl2]Cl.H2O.CH3OH (space group P21/a, a = 14.821(5) A, b = 10.270(4) A, c = 17.663(6) A, beta = 108.87(3) degrees, V = 2544(2) A3, Z = 4, R1 = 0.0973, wR2 = 0.2136). This structure displays a Ni(II) binuclear complex of L2 in which the phenolic oxygen and a chlorine ion bridge the two close Ni(II) ions.

Observations of CH4, C2H6, and C2H2 in the stratosphere of Jupiter.

We have performed high-resolution spectral observations at mid-infrared wavelengths of CH4 (8.14 micrometers), C2H6 (12.16 micrometers), and C2H2 (13.45 micrometers) on Jupiter. These emission features probe the stratosphere of the planet and provide information on the carbon-based photochemical processes taking place in that region of the atmosphere. The observations were performed using our cryogenic echelle spectrometer CELESTE, in conjunction with the McMath-Pierce 1.5-m solar telescope between November 1994 and February 1995. We used the methane observations to derive the temperature profile of the jovian atmosphere in the 1-10 mbar region of the stratosphere. This profile was then used in conjunction with height-dependent mixing ratios of each hydrocarbon to determine global abundances for ethane and acetylene. The resulting mixing ratios are 3.9(+1.9)(-1.3) x 10(-6) for C2H6 (5 mbar pressure level), and 2.3 +/- 0.5 x 10(-8) for C2H2 (8 mbar pressure level), where the quoted uncertainties are derived from model variations in the temperature profile which match the methane observation uncertainties.

Jupiter's atmospheric composition from the Cassini thermal infrared spectroscopy experiment.

The Composite Infrared Spectrometer observed Jupiter in the thermal infrared during the swing-by of the Cassini spacecraft. Results include the detection of two new stratospheric species, the methyl radical and diacetylene, gaseous species present in the north and south auroral infrared hot spots; determination of the variations with latitude of acetylene and ethane, the latter a tracer of atmospheric motion; observations of unexpected spatial distributions of carbon dioxide and hydrogen cyanide, both considered to be products of comet Shoemaker-Levy 9 impacts; characterization of the morphology of the auroral infrared hot spot acetylene emission; and a new evaluation of the energetics of the northern auroral infrared hot spot.