O2 Lines Research Articles

A GIANO-TNG high-resolution infrared spectrum of the airglow emission

A flux-calibrated high resolution spectrum of the airglow emission is a practical lambda-calibration reference for astronomical spectral observations. It is also useful for constraining the molecular parameters of the OH molecule and the physical conditions in the upper mesosphere. methods: We use the data collected during the first technical commissioning of the GIANO spectrograph at the Telescopio Nazionale Galileo (TNG). The high resolution (R~50,000) spectrum simultaneously covers the 0.95-2.4 micron wavelength range. Relative flux calibration is achieved by the simultaneous observation of spectrophotometric standard star. results: We derive a list of improved positions and intensities of OH infrared lines. The list includes Lambda-split doublets many of which are spectrally resolved. Compared to previous works, the new results correct errors in the wavelengths of the Q-branch transitions. The relative fluxes of OH lines from different vibrational bands show remarkable deviations from theoretical predictions: the Deltav=3,4 lines are a factor of 2 and 4 brighter than expected. We also find evidence of a significant fraction (1-4%) of OH molecules with ``non-thermal'' population of high-J levels. Finally we list wavelengths and fluxes of 153 lines not attributable to OH. Most of these can be associated to O2, while 37 lines in the H band are not identified. The O2 and unidentified lines in the H band account for ~5% of the total airglow flux in this band.

Quantitative Trait Loci for Ruminal Degradability in opaque endosperm2 (o2) Maize

ABSTRACTAlthough opaque endosperm2 (o2) gene that alters protein composition of maize (Zea mays L.) endosperm improves dry matter degradability (DMD) in ruminants it is also associated with soft endosperm texture, low yield, and susceptibility to diseases and insects. To circumvent the undesirable traits, breeders developed high lysine modified endosperm genotypes called quality protein maize (QPM). The objectives of this study were to determine whether DMD is maintained in modified endosperm and to map major quantitative trait loci (QTLs) associated with ruminal in situ DMD (RDMD). Composited 1.5‐g ground grain samples of 140 recombinant inbred lines (RILs) derived from the cross between o2 (B73o2) and QPM (CML161) lines were assayed for 14‐h RDMD in three rumen‐cannulated, mid‐lactation Holstein cows (Bos taurus) and 0‐h rapidly soluble dry matter (RSDM) in tepid water. The RILs were grown in Texas and were evaluated for RDMD at Madison, WI. Slowly degradable dry matter (SDDM = RDMD – RSDM) was estimated. Kernel opacity was positively correlated to 14‐h RDMD (r = 0.68 and 0.71 in 2005 and 2006, respectively; P < 0.05). Quantitative trait loci for 14‐h RDMD were detected on chromosomes 4, 5, 7, 9, and 10; QTLs for RSDM were detected on chromosomes 3, 5, 7, and 10; and QTLs for SDDM were detected on chromosomes 5, 6, and 9. Quantitative trait loci for 14‐h RDMD and RSDM colocated on chromosomes 5, 7, and 10 might be genomic regions influencing 14‐h RDMD mainly through kernel modification. Quantitative trait loci for 14‐h RDMD and/or SDDM, on chromosomes 6 (SDDM) and 9 (colocated) where 14‐h RDMD appears to be mediated through SDDM and most likely enzymatic RDMD, may be good candidates for improvement of RDMD.

Transition frequencies of oxygen B-band lines measured with optical frequency comb assisted cavity ring-down spectroscopy

Transition frequencies of weak B-band lines of O2 were measured with low uncertainties. These results were compared to data available in the literature. In order to achieve reported accuracy we took into account in the data analysis several subtle line-shape effects, such as speed dependence of collisional broadening and Dicke narrowing. We found that the speed-dependent Nelkin-Ghatak profile can properly describe experimental line shapes in the investigated pressure range of up to 22 Torr. Our experimental setup consists of the Pound-Drever-Hall locked frequency-stabilized cavity ring-down spectrometer. This spectrometer provides high-resolution and very high signal-to-noise ratio of measured spectra. It was recently linked to the optical frequency comb working in the visible region of spectrum. This upgrade allows for accurate determination of the absolute frequency axis of the CRD spectrum by direct measurement of the probe laser frequency.

Intracavity absorption spectroscopy with a tunable multimode traveling-wave ring Ti:sapphire laser

A tunable multimode unidirectional traveling-wave Ti:sapphire laser was developed to measure in situ the atmospheric absorption spectra using intracavity absorption spectroscopy. The effective absorption path length was 2100 km. O2 and H2O vapor lines in atmosphere with absorption coefficients of 10(-6)-10(-8) cm(-1) were measured with uncertainties <5%, and the absorption coefficients were in agreement with those estimated from the HITRAN database. By tuning the wavelength, a weak absorption line with an absorption coefficient of 10(-9) cm(-1) was measured with a sensitivity of 2×10(-10) cm(-1). The sensitivity was limited by the residual parasitic variation that appeared in the spectrum.

The Astrophysical Methods for Long-Term Monitoring of the CO&lt;SUB&gt;2&lt;/SUB&gt; Content in the Earth Atmosphere

We alert the astronomers carrying high-resolution observations of the Sun to a possibility to study global changes in the composition of the Earth atmosphere and other atmospheric characteristics using spectra containing telluric lines. This possibility is illustrated by solar observations carried in Moscow in visible and near infrared spectrum. A com- parison of equivalent widths O2 (λ6295 A) and CO2 (λ20,700 A) lines, recorded with a spectrograph on the large vertical solar telescope ATB-1 at the Sternberg State Astronomical Institute from 1969 to 2007 reveals that during this period oxy- gen content in atmosphere above Moscow remained constant (within the limits of observational accuracy) whereas the carbon dioxide content increased significantly.

Comparing radial velocities of atmospheric lines with radiosonde measurements

The precision of radial velocity (RV) measurements depends on the precision attained on the wavelength calibration. One of the available options is to use atmospheric lines as a natural, freely available wavelength reference. Figueira et al. measured the RV of O2 lines using High Accuracy Radial velocity Planet Searcher (HARPS) and showed that the scatter was only of ∼10 m s−1 over a time-scale of 6 yr. Using a simple but physically motivated empirical model, they demonstrated a precision of 2 m s−1, roughly twice the average photon noise contribution. In this paper, we take advantage of a unique opportunity to confirm the sensitivity of the telluric absorption lines’ RV to different atmospheric and observing conditions by means of contemporaneous in situ wind measurements. This opportunity is a result of the work done during site testing and characterization for the European Extremely Large Telescope (E-ELT). The HARPS spectrograph was used to monitor telluric standards while contemporaneous atmospheric data were collected using radiosondes. We quantitatively compare the information recovered by the two independent approaches. The RV model fitting yielded results similar to that of Figueira et al., with lower wind magnitude values and varied wind direction. The probes confirmed the average low wind magnitude and suggested that the average wind direction is a function of time as well. However, these results are affected by large uncertainty bars that probably result from a complex wind structure as a function of height. The two approaches deliver the same results in what concerns wind magnitude and agree on wind direction when fitting is done in segments of a couple of hours. Statistical tests show that the model provides a good description of the data on all time-scales, being always preferable to not fitting any atmospheric variation. The smaller the time-scale on which the fitting can be performed (down to a couple of hours), the better the description of the real physical parameters is. We then conclude that the two methods deliver compatible results, down to better than 5 m s−1 and less than twice the estimated photon noise contribution on O2 lines’ RV measurement. However, we cannot rule out that parameters α and γ (dependence on airmass and zero-point, respectively) have a dependence on time or exhibit some cross-talk with other parameters, an issue suggested by some of the results.

3-mm wave spectroradiometer for studies of atmospheric trace gases

We developed a high-sensitivity receiving and measuring facility designed for observations of the ozone O3 and carbon monoxide CO spectral lines by the method of ground-based remote sensing of the atmosphere in the 90–116 GHz frequency range. The measurement and calibration procedure is described in detail. The results of observations of the O3 and CO emission lines at frequencies 110.836 amd 115.271 GHz, respectively, are presented. The sensitivity level of the receiving and measuring facility, which was implemented in the experiment using a filter-bank analyzer and a Fourier spectrum analyzer is determined.

Molecular Marker-Assisted Selection for o2 Introgression Lines with o16 Gene in Corn

Mutant opaque-2 ( o2) is commonly used as a donor in high lysine corn ( Zea mays L.). Currently, the highest lysine content of the o2 line or the resultant hybrid is only 0.4%, and it is necessary to breed corn lines with higher lysine content. This study aimed at transferring another high lysine gene, opaque-16 ( o16), into o2 corn line. The o16 donor parent QCL3021 was crossed and backcrossed with Taixi 19 ( o2 line) until the BC 2F 4 generation. In every backcrossing and subsequent inbred generation, o2 and o16 genes were selected using simple sequence repeat (SSR) markers umc1066 and umc1141, respectively. The backgrounds of selected plants were screened with 243 SSR markers spanning over the whole corn genome. Grain lysine content was determined using the dye-binding lysine (DBL) method. In the BC 2F 4 generation, 17 lines carrying both o2 and o16 were harvested, of which the genetic background recovery ratios were as high as 92-95%. This indicated that the genome of these lines was highly identical with the o2 line. Lysine contents of the selected plants ranged from 0.47% to 0.60%. The average lysine content of these plants was 125% higher than that of normal corn, 23% higher than the high parent Taixi 19, and 64% higher than the low parent QCL3021.

Quantitative Trait Loci for Endosperm Modification and Amino Acid Contents in Quality Protein Maize

The deficient protein quality of corn (Zea mays L.) grain can be improved by replacing normal Opaque2 (O2) alleles with nonfunctional mutant o2 alleles. Unfortunately, o2 alleles are associated with soft endosperm texture, poor yield, and susceptibility to diseases and insects. Plant breeders have been able to restore a desirable ratio of hard to soft endosperm in o2 germplasm. These modified genotypes are known as Quality Protein Maize (QPM). Neither the mechanism nor the genetic components controlling endosperm modification in QPM lines are well understood. Using a population of recombinant inbred lines, derived from a cross between an o2 line and a QPM line, and a novel evaluation method for endosperm modification, quantitative trait loci (QTL) were mapped for traits related to the modification of endosperm texture and the content of the essential amino acids lysine, tryptophan, and methionine. Quantitative trait loci clusters for endosperm texture traits were detected on chromosomes 3, 5, 6, and 8, together accounting for 62 to 68% of the observed variation. For traits related to amino acid contents, QTL clusters were located on chromosomes 7 and 8, explaining up to 39% of the observed variation. The elucidation of the genetic mechanisms of the modification of o2 endosperm and essential amino acid contents provides valuable information and important tools to plant breeders and plant scientists interested in improving the quality of cereal grains.

Role of BP1, a Novel Transcription Factor, in Antiestrogen Resistance.

Abstract Background: Breast cancer patients with early stage, estrogen receptor (ER) positive tumors generally respond well to adjuvant treatment with the antiestrogen tamoxifen. The result is a 40-50% decrease in annual risk of recurrence. However, almost all patients with metastatic breast cancer and about half of the patients who receive tamoxifen exhibit recurrence due to resistance to antiestrogens. Through a better understanding of the mechanisms of resistance to antiestrogen therapy, it may be possible to design more effective treatment for those women with ER positive tumors who develop resistance, and possibly for those women with ER negative tumors, who do not respond to antiestrogen therapy. We are studying a homeotic transcription factor, BP1, that may be involved in antiestrogen resistance. BP1 is upregulated in 80% of invasive ductal breast tumors and is associated with aggressive tumors: 100% of ER negative tumors were BP1 positive, compared with 73% of ER positive tumors. We have evidence that BP1 protein (pBP1) is involved in both genomic and non-genomic ER signaling.Materials and Methods: MCF-7 derivatives overexpressing BP1, called O2 and O4 cells, were grown in serum free medium for 48 hr., followed by Western blot analysis to assess the level of phosphorylated Akt and phosphorylated ER. An electrophoretic mobility shift assay (EMSA) was performed with pBP1 transcribed and translated in wheat germ extract to demonstrate pBP1 binding to a specific DNA sequence. Cell lines were immunostained to determine levels of ER protein.Results: (1) Genomic signaling: There is a consensus DNA binding site in an intron of the ER. pBP1 binds to that site, shown by EMSA. Immunostaining of O2 and O4 cell lines overexpressing pBP1 demonstrates that there is reduced ER protein on cells overexpressing BP1, consistent with the idea that BP1 directly represses the ER and that BP1 is more frequently expressed in ER negative tumors than in ER positive tumors. (2) Non-genomic signaling: phosphorylation of Akt was examined in O2 cells after growth in phenol red-free, serum free medium. Using a phosphorylation-specific antibody, we observed phosphorylation of Akt in O2 cells. In contrast, there was little or no phosphorylation of Akt in empty vector control cells. Phosphorylation of the ER was assessed in O4 cells, where there was a detectable increase in ER phosphorylation in the cells overexpressing BP1 compared with empty vector controls.Discussion: Our data support the hypothesis that pBP1 binds to the ER, directly repressing its activity, which could lead to estrogen independence. Moreover, we have evidence that high levels of pBP1 lead to increased phosphorylation of both Akt and the ER, part of a non-genomic signaling pathway that causes estrogen independence. Moreover, in collaboration with Dr. Barbara Vonderhaar, we have shown that 20% of the tumors in mice injected with O2 or O4 cells are estrogen independent, consistent with these data. Thus, we hypothesize that BP1 is intimately involved in antiestrogen resistance, making it a strong potential therapeutic target. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5144.

Recent progress in spectroscopy and its effect on line-by-line calculations for the validation of radiation codes for climate models

The evolution of spectroscopic data from 2008 to 2009 and its effect on line-by-line (LBL) calculations for the validation of radiation codes for climate models is the subject matter of this paper. The authors have used the standard midlatitude summer (MLS) atmosphere in all numerical experiments. Long-wave calculations with the current (2008) and previous (2002) HITRAN variations revealed a very good agreement between them: the discrepancies are less than ∼0.1 W/m2 in flux calculations (H2O, CO2, and O3 lines and continuums). The replacement of the latest (MT CKD-2.1) version by the previous one (CKD-2.4) gave a discrepancy of up to ∼0.9 W/m2. The shortwave calculations with the same HITRAN versions, on the contrary, have revealed a disagreement greater than that observed during the previous decade: the additional absorption only in the water vapor lines in the downward fluxes has reached 2.6 and 2.1 W/m2 (∼1.5 and 2.9%) for solar zenith angles (SZA) of 30° and 75°, respectively. The additional absorption with the latest and previous HITRAN versions along with the continuum models has reached 2.0 and 0.4 W/m2 for SZA of 30° and 75°, respectively (H2O, CO2, O2, and O3 lines and continuums). It has been found that the total neglect of the line-mixing effect can produce essential errors of about 2.5 W/m2 (1.5%) in the long-wave flux calculations. Nevertheless, their usual treatment with the use of a line shape correction or first-order approximation gave a satisfactory result: the errors in the long-wave flux calculations were below ∼0.14 W/m2 (∼0.1%) and ∼0.03 W/m2, respectively.

Calculations of ozone line shifting induced by N2 and O2 pressure

Ozone line shifts by nitrogen and oxygen pressure are computed for the ν1 + ν3, 2ν1 and 2ν3 bands of the 5 μm spectral region by a semiempirical approach. The calculated values agree with measurements better than 0.001 cm−1 atm−1 for 98% of O3–N2 lines and 87% of O3–O2 lines. In contrast with the water molecule case, the polarization components of the interaction potential are shown to contribute to the line shift more efficiently than the electrostatic interactions. As intermediate results, the mean dipole polarizability and the components of the polarizability tensor for the vibrational states (101), (200), and (002) of ozone molecule are determined by least-squares fitting of theoretical shifts to some experimental values. The temperature exponents for the ν1 + ν3 band lines are also estimated.

Fast and Accurate Radiative Transfer in the Microwave With Optimum Spectral Sampling

Optimal spectral sampling (OSS) is a computationally fast and accurate method for modeling sensor-band transmittances and radiances. The spectral response of a sensor channel is approximated by an optimally weighted average of monochromatic radiative transfer calculations at optimally selected points. The absorption coefficients for the selected points are obtained from prestored lookup tables. Analytical Jacobians are produced in conjunction with the radiances with very little added computational burden. A microwave version of the OSS training algorithm and forward model has been developed in parallel with the infrared version. The microwave model treats O2 and N2 as fixed gases and H2O and O3 as variable gases. Several reference line-by-line (LBL) models are available for training. The method of tabulating and interpolating absorption coefficients has been optimized for execution speed. Results are shown for OSS application to several current and future microwave sounders. With a selected requirement of 0.05-K rms error (with respect to the reference LBL model), the number of monochromatic points required varies from one, for most window channels, to about four for channels embedded in the 60-GHz O2 line complex and along the 183-GHz H2O line. Even in the cases where a single point is adequate, the optimal point does not necessarily coincide with the center frequency of the channel.

Time-dependent depolarization of aligned HD molecules

An aligned sample of HD(v = 1, J = 2, M(J) = 0) molecules is prepared under collision-free conditions using the S(0) stimulated Raman pumping transition. Subsequent coupling to the spins of the deuteron I(D) and the proton I(H) causes the initial degree of alignment to oscillate and decrease as monitored over the time range from 0-13 mus via the O2 line of the [2 + 1] REMPI E,F(1)Sigma-X(1)Sigma (0,1) band. The time dependence of the rotational alignment is also calculated using both a hierarchical coupling scheme in which the rotational angular momentum J is regarded first to couple to I(D), and then the resultant F(i) to couple to I(H), to form the total angular momentum F and a non-hierarchical coupling scheme in which the HD energy level structure is not assumed to be diagonal in the |I(H)(JI(D))F(i)FM(F)> basis set. The experimental data is in good agreement with the non-hierarchical calculation but not with the hierarchical calculation, as expected for this system. Additionally, we calculate the time dependence of the H and D nuclear spin polarizations.

Heterofertilization of the opaque-2 endosperm in maize

Selection on endosperm traits among individual kernels is very important in maize because the characteristics of the kernel, especially the endosperm, are directly related to quality and yield. However the accuracy of the selection according to endosperm phenotype may be affected by heterofertilization. The objective of this work was to investigate the frequency of heterofertilization of opaque-2 (o2) kernels in maize. Three BC(1)F(1) populations using o2 lines as recurrent parents and some BC(1)F(2) progenies were used to investigate endosperm phenotypes and plant genotypes. The plant genotypes were determined using simple sequence repeat (SSR) markers, phi057 or phi112, which are sequences located within the Opaque-2 (O2) gene; the endosperm phenotypes were observed visually. In the BC(1)F(1) populations, the frequency of heterofertilization was 0 approximately 4.545%. This result indicates that there may be up to a 5% difference between the selections based on endosperm phenotype and plant genotype in a backcross breeding program. Molecular marker assisted selection should be a more accurate selection procedure. In addition, we discuss the relationship between the endosperm heterofertilization of o2 maize and the variations within the O2 locus.

The temperature of the Venus mesosphere from O2 (aΔg1) airglow observations

We have used near-infrared spectroscopic observations of the Venus nightside taken with the Infrared Imager and Spectrograph 2 (IRIS2) on the Anglo–Australian Telescope to derive temperature maps for the Venus mesosphere at an altitude of ∼95 km. The temperatures are derived from the distribution of rotational line intensities in the O2 (aΔg1) airglow band at 1.27 μm. To obtain reliable temperatures at the relatively low spectral resolution of IRIS2, we have developed a forward modeling approach to handle the blending of individual O2 lines and the telluric absorption in the same O2 band. The technique provides temperature retrievals with accuracy comparable to, or better than that of previous high-spectral resolution determinations. The resulting temperature maps show spatial temperature structure that varies from night to night, as does the intensity distribution. Intensity weighted mean temperatures range from about 181 to 196 K. The temperatures are typically 15–30 K higher than those expected from the Venus International Reference Atmosphere (VIRA) profile. The temperatures fall in regions of low O2 emission rate to values closer to the VIRA levels. Our temperatures are similar to, but slightly lower than those obtained from stellar occultation measurements with SPICAV on Venus Express. We suggest that we are seeing a region of locally enhanced temperature caused by compressional heating in the downwelling gas around the antisolar point.

Development of precipitation retrievals at millimeter and sub‐millimeter wavelengths for geostationary satellites

We study the potential of millimeter and sub‐millimeter wavelengths for precipitation retrieval from geostationary sensors based on mesoscale cloud modeling and radiative transfer computation. Hydrometeor profiles simulated with the Meso‐NH cloud resolving model for five European midlatitude situations are used to compute the brightness temperatures at frequencies from 23.8 to 875 GHz with the Atmospheric Transmission at Microwaves (ATM). Performances of both rain detection and rain rate retrieval are analyzed for different frequency sets, over ocean and land separately, and compared to the user requirements. The performances of a frequency set such as that already planned for geostationary satellites (with channels in the O2 lines at 50, 118, and 424 GHz, and in the H2O lines at 183, 325, 380 GHz) satisfy the requirements for Numerical Weather Prediction and NoWCasting in terms of rain detection as well as for rain rate retrieval above 1 mm/h. Suppressing the 50 GHz O2 channels does not seriously degrade the performances, except for rain rate below 1 mm/h, and, in addition, limits the spatial resolution problem from a geostationary orbit. Adding the thermal infrared observations has a limited impact. The retrieval of other hydrometeor quantities (cloud, ice) is also tested as well as the possibility to retrieve rain and the other hydrometeor profiles. These theoretical results are evaluated at close‐to‐millimeter wavelengths with coincident AMSU‐B and radar observations (BALTEX and CAMRa). The results are degraded with respect to the theory, as expected, but are consistent with the observations.

Experiments for modelling the biodegradation of wastewater in sequencing batch reactors

Three types of wastewater were considered: typical municipal wastewater and the effluent of a dairy industry, both polluted with organic carbon and nitrogen, and wastewater typical of a chemical industry, containing toxic or recalcitrant compounds (4-chlorophenol). Sequencing batch reactors (SBRs) were considered. Process experiments were performed to provide experimental data for parameter identification of the dynamical models of the SBRs. The processes were instrumented with sensors to measure O2, NH3, T, pH, OUR, and other off line measurements (e.g.: NO2 − and NO3 −, COD, phenol concentration, microbiological counts and activities) in order to study more accurately the behaviour of the biomasses. However, the general idea is to design a system with a minimal number of sensors.

High‐resolution terrestrial nightglow emission line atlas from UVES/VLT: Positions, intensities, and identifications for 2808 lines at 314–1043 nm

The atlas of terrestrial nightglow emission lines from spectra of the night sky obtained from the Ultraviolet and Visual Echelle Spectrograph (UVES) on the 8.2‐m UT2 telescope at the Very Large Telescope (VLT), European Southern Observatory, Cerro Paranal, Chile, consists of 2808 line positions, line widths, and intensities over the 314–1043 nm spectral range (Hanuschik, 2003). These lines have been absolute intensity calibrated and measured at a spectral resolution (λ/Δλ) of ∼43,000–45,000. Presented here are spectroscopic identifications for 98% of the lines in the atlas, made primarily through comparisons with synthetic spectra of prominent OH and O2 nightglow emission systems. The ability to simulate these systems successfully has shown that there are many additional lines that could be added to the atlas. We believe that all the O2 and OH lines in the measured region can now be successfully modeled with an accuracy better than the instrumental spectral resolution.

Odin Detection of O 2

We present the detection of molecular oxygen with Odin toward the dense molecular core rho Oph A, which is part of a region of active star formation. The observed spectral line is the (N,J = 1,1-1,0) ground state transition of molecular oxygen at 119 GHz (2.5 mm wavelength). The center of the line is at the LSR velocity of a number of optically thin lines from other species in the region and the O2 line also has a very similar, narrow, line width. Within the 10 arcmin beam, the integrated line intensity is 28 mK km/s, which corresponds to 5 sigma of the rms noise. A standard LTE analysis results in an O2 abundance of 5E(-8), with an uncertainty of at least a factor of two. We show that standard methods, however, do not apply in this case, as the coupling of the Odin beam to the source structure needs to be accounted for. Preliminary model results indicate O2 abundances to be higher by one order of magnitude than suggested by the standard case. This model predicts the 487 GHz line of O2 to be easily detectable by the future Herschel-HIFI facility, but to be out of reach for observations on a shorter time scale with the Odin space observatory.