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High-altitude illness includes the pulmonary and cerebral syndromes that can develop in unacclimated persons after an ascent to high altitude. The three major types of high-altitude illness are acute mountain [...]

In addition to practicing in emergency medicine, I am a Fellow of the Academy of Wilderness Medicine, Wilderness Medical Society, and I volunteer with a search and rescue (SAR) team [...]

RÉSUMÉDes cartes hebdomadaires de la glace de mer produites par le Centre national des glaces (NIC) de 1972 à 1994 ont été rendues publiques récemment en soutien à la recherche environnementale. Ces cartes étaient conçues à l'origine comme outil d'aide à la navigation pour les navires opérant dans les eaux infestées de glace de mer dans l'hémisphère nord. Toutefois, on a réalisé très tôt que ces données constituaient une ressource unique pour les chercheurs en milieu Arctique, apportant une contribution significative aux ensembles de données sur la glace de mer compilées par Walsh (1978) et autres. Les enregistrements de concentration de glace dérivés couramment des données des capteurs satellitaires hyperfréquences passifs sont semblables à l'ensemble de données du NIC en termes de résolution, d'étendue et de période d'enregistrement, mais ces ensembles de données hyperfréquences peuvent souffrir de biais systématiques reliés au processus et aux algorithmes de formation de l'image utilisés pour déduire la concentration de glace à partir des données brutes. Bien que l'ensemble des données numériques de glace de mer du NIC ait ses propres limitations, les premiers enregistrements dans le temps précèdent les enregistrements de données par capteurs hyperfréquences passifs et permettent d'éviter certains de ces biais inhérents. Cet article décrit les caractéristiques spatiales et thématiques de l'ensemble de données historiques du NIC de même que les données numériques et analogiques et les méthodes d'analyse utilisées pour créer l'ensemble de données. Cette étude analyse aussi brièvement les changements à long terme dans le couvert de glace dans l'Arctique. L'ensemble de données du NIC révèle que les patrons de concentration de glace de mer dans les secteurs Atlantique et Pacifique de l'Arctique varient en réponse aux changements dans l'Oscillation de l'Atlantique Nord. Ce résultat est cohérent avec les résultats des recherches d'autres chercheurs qui ont utilisé d'autres ensembles de données.

Using 0.002 cm resolution Fourier transform absorption spectra of an O enriched ozone sample, an extensive analysis of the v 1 + v 3 bands of the OOO and OOO isotopomers of ozone has been performed for the first time. The experimental rotational levels of the (101) vibrational states were satisfactorily reproduced using a Hamiltonian matrix that takes into account the observed rovibrational resonances. More precisely, for OOO, as for the other C 2 v -type ozone isotopomers, it was necessary to account for the Coriolis type resonances linking the (101) rotational levels with the levels of the (200) and (002) vibrational states and the Darling-Dennison interaction coupling the levels of (200) with those of (002). For the C s -type isotopomer, namely OOO, as for OOO and OOO, it proved necessary to also account for an additional Δ K a =±2 resonance involving the rotational levels from (101) and (002) (J.-M. Flaud and R. Bacis, Spectrochimica Acta Part A 54 , 3-16 (1998)). Using a Hamiltonian matrix which takes these resonances explicitly into account, precise vibrational energies and rotational and coupling constants were deduced, leading to the following band centers: v 0 ( v 1 + v 3 )=2078.3496 cm for OOO and v 0 ( v 1 + v 3 )=2098.8631 cm for OOO.

Room temperature argon broadened halfwidth and pressure-induced line shift coefficients have been determined for 118 transitions in the ν_4 band of ^12CH_4 from analysis of high resolution laboratory absorption spectra recorded with the McMath Fourier transform spectrometer operated on Kitt Peak by the National Solar Observatory. Transitions up to J″ = 12 have been measured using a nonlinear least-squares spectral fitting procedure. The variation of the measured halfwidth coefficients with symmetry type and rotational quantum number is very similar to that measured previously for N_2 and air broadening, but the absolute values of the argon broadening coefficients are all smaller. On average, the ratio of the argon broadened halfwidth coefficient to the corresponding N_2 broadened halfwidth coefficient is 0.877 ± 0.017 (2σ). More than 95% of the pressure-induced shifts are negative with values ranging from −0.0081 to +0.0055 cm^−1 atm^−1. The pressure shifts in argon are nearly equal to corresponding values measured previously in N_2 and air.

Absolute intensities for 430 transitions belonging to eleven rotation–vibration bands of ^12C^16O_2, ^13C^16O_2, and ^16O^12C^18O in the 3140–3410-cm^−1 spectral region have been determined by analyzing spectra recorded at 0.01-cm^−1 resolution with the Fourier transform spectrometer in the McMath solar telescope complex at the National Solar Observatory on Kitt Peak. The data were recorded at room temperature and low pressures (<10 Torr) using a natural sample of carbon dioxide. Intensities were derived using a nonlinear least-squares spectral fitting procedure, and the values obtained for each band have been analyzed to determine the vibrational band intensity and nonrigid rotor coefficients. An alternative mathematical formulation is shown in the case of bands for which the Coriolis effect is large and the Q-branch line intensities were not determinable either because they were severely blended or absent from the spectra. Comparisons are made between the results obtained in this study and other published values.

Air-broadened and N_2-broadened halfwidth and pressure shift coefficients of 294 transitions in the ν_4 and ν_2 bands of 12CH_4 have been measured from laboratory absorption spectra recorded at room temperature with the Fourier transform spectrometer in the McMath solar telescope facility of the National Solar Observatory. Total pressures of up to 551 Torr were employed with absorption paths of 5–150 cm, CH_4 volume mixing ratios of 2.6% or less, and resolutions of 0.005 and 0.01 cm^−1. A nonlinear least-squares spectral fitting technique has been utilized in the analysis of the twenty-five measured spectra. Lines up to J″ = 18 in the ν_4 band and J″ = 15 in the ν_2 band have been analyzed.

Absolute intensities were measured at room temperature for thirty-nine lines in the qQ, qP, and qR branches of the ν_3 (A1) parallel-type band of ^12CH_3D between 1250 and 1340 cm^−1 using a tunable diode laser spectrometer. Although the line intensities were determined to a precision ≈3%, the square of the vibrational transition dipole moment matrix element derived from each mean line intensity varied by ≈20%, indicating intensity perturbations possibly caused by Coriolis interaction with the nearby ν_6 fundamental. Room temperature air- and N_2-broadened halfwidths have also been determined for seventeen of these lines and the measured halfwidth values varied from 0.023 cm^−1 atm^−1 for high J,K transitions to ∼0.067 cm^−1 atm^−1 for low J,K transitions. The average of the ratios of N_2- to air-broadened halfwidths was 1.01, with a standard deviation of 0.01, indicating almost equal broadening efficiencies for N_2 and air. Room temperature self-broadened halfwidths were also determined for three transitions with a mean value of 0.0803 ± 0.0010 cm^−1 atm^−1.

Air-broadened and N_2-broadened halfwidths at room temperature for twenty-five transitions in the ν_4 fundamental band of ^12CH_4 have been determined from IR absorption spectra recorded with a tunable diode laser spectrometer. Two tunable diode lasers operating in the 1250–1380-cm^−1 region were used to obtain these data. Air-broadened halfwidths for twenty of these lines were also determined from additional spectra recorded at 0.01-cm^−1 resolution with the Fourier transform spectrometer in the McMath solar telescope complex on Kitt Peak. The air-broadened halfwidths obtained from these two techniques are very consistent with agreement better than 3% in most cases.

Absolute intensities for over 800 transitions belonging to twelve bands of ^12C^16O_2, ^16O^12C^18O, ^16O^12C^17O, and ^16O^13C^18O molecules in the 2395–2680-cm^−1 spectral region have been derived using a nonlinear least-squares spectral fitting procedure. The data used in the analysis were recorded at room temperature and low pressure (<10 Torr) with the 0.01-cm^−1 resolution Fourier transform spectrometer in the McMath solar telescope complex at the National Solar Observatory. The measured intensities obtained for each band have been analyzed to derive the vibrational band intensity and F-factor coefficients. The results are compared with other published values.

Absolute intensities for over 300 lines of eleven relatively weak bands of ^12C^16O_2, ^13C^16O_2, ^16O^12C^18O, and ^16O^12C^17O near 2050 cm^−1 have been measured from 0.01-cm^−1 resolution laboratory spectra recorded with the Fourier transform spectrometer in the McMath solar telescope complex at the National Solar Observatory on Kitt Peak. The spectral data were obtained with a natural sample of carbon dioxide at room temperature and low pressure (<10 Torr) and have a signal-to-rms noise of ≈4000. The intensities were determined using the technique of nonlinear least-squares spectral curve fitting. The measured line intensities obtained for each band have been analyzed to derive the vibrational band intensity and F-factor coefficients. The results are compared to values from the 1982 Air Force Geophysics Laboratory line parameters compilation.

A nonlinear least-squares fitting procedure has been used to derive absolute intensities for lines in the P, R, and Q branches of the (11^10)_II ? 00^00 band of ^12C^16O_2 (band center = 1932 cm^−1) from long-path 0.01-cm^−1 resolution laboratory spectra. The spectral data were recorded at room temperature and low pressure (<10 Torr) with the Fourier transform spectrometer in the McMath solar telescope complex at Kitt Peak National Observatory. The observed line intensities were analyzed to derive the vibrational band intensity and F-factor coefficients. To obtain a good fit to the data, it was necessary to include terms in the expression for the F factor, which account for Coriolis-type and Fermi-type interactions and centrifugal distortion effects.

Air- and nitrogen-broadened half-widths and line shifts at room temperature for more than 60 individual vibration–rotation transitions in the ν_1 fundamental band of ^16O_3 and several transitions in the ν_3 band were determined from infrared absorption spectra. These spectra were recorded at 0.005-cm^−1 resolution with a Fourier-transform spectrometer. A tunable-diode-laser spectrometer operating in the 1090–1150-cm^−1 region was also used to record data on oxygen-, nitrogen-, and air-broadened half-widths for selected individual transitions. The nitrogen- and air-broadened half-widths determined by these two different measurement techniques are consistent to within 4%. The results are in good agreement with other published measurements and calculations.

Air-, nitrogen-, and oxygen-broadened halfwidth and pressure-induced line shift coefficients have been measured for over seventy-five individual vibration–rotation transitions in the ν_3 fundamental band of ^13CH_4 at 3 μm from room temperature IR laboratory absorption spectra recorded at a 0.01-cm^−1 resolution with a Fourier transform spectrometer. Transitions up to J″ = 13 in the P-branch and J″ = 7 in the R-branch were analyzed using a nonlinear least-squares curve fitting technique assuming a Voigt line shape. From the analysis, we have determined the mean ratios of air- to nitrogen-broadened and air- to oxygen-broadened halfwidth coefficients obtained for the same transitions as 1.00 ± 0.03 and 1.06 ± 0.04, respectively. The measured pressure shift coefficients were predominantly negative, and the mean and standard deviation values for air-, nitrogen-, and oxygen-broadened shifts were −0.0067 ± 0.0032, −0.0068 ± 0.0041, and −0.0066 ± 0.0028 cm^−1 atm^−1, respectively. Comparisons are made with the results obtained for similar transitions in the ν_3 band of ^12CH_4 and the ν_4 band of ^13CH_4.

Absolute intensities have been determined for over 700 unblended lines in twenty bands of ^12C^16O_2, ^13C^16O_2, ^16O^12C^18O, and ^16O^12C^17O in the 4.8-μm spectral region. The spectral data used in the analysis were recorded at room temperature and low pressure (<10 Torr) with the Fourier transform interferometer in the McMath solar telescope complex of the National Solar Observatory. A natural sample of ultrahigh-purity carbon dioxide was used in the experiment. For each band, the measured line intensities have been fitted to derive the vibrational band intensity and coefficients of the F factor. These derived quantities are compared to values assumed in calculation of the 1982 Air Force Geophysics Laboratory line parameters compilation.

Air-broadened and N_2-broadened halfwidths at room temperature for twenty-five transitions in the ν_4 fundamental band of ^12CH_4 have been determined from IR absorption spectra recorded with a tunable diode laser spectrometer. Two tunable diode lasers operating in the 1250–1380-cm^-1 region were used to obtain these data. Air-broadened halfwidths for twenty of these lines were also determined from additional spectra recorded at 0.01-cm^-1 resolution with the Fourier transform spectrometer in the McMath solar telescope complex on Kitt Peak. The air-broadened halfwidths obtained from these two techniques are very consistent with agreement better than 3% in most cases.

A nonlinear least-squares spectral fitting procedure has been used to derive experimental absolute intensities for over 300 unblended lines belonging to twelve bands of^12C^16O_2, ^13C^16O_2, ^16O^12C^18O, ^16O^12C^17O, and ^16O^13C^18O in the 5.2-μm region. The spectral data were recorded at 0.01-cm^−1 resolution and room temperature with the Fourier transform spectrometer in the McMath solar telescope complex at the National Solar Observatory on Kitt Peak and have a signal-to-rms noise ratio of 2000–4000. A natural sample of carbon dioxide was used as the sample gas. For each band, the measured line intensities have been analyzed to derive the vibrational band intensity and coefficients of the F factor. The results are compared to the values used to calculate the intensities in the 1982 Air Force Geophysics Laboratory line parameters compilation.

Air-broadened halfwidths and pressure-induced line shifts in the ν_4 fundamental of ^13CH_4 were determined from spectra recorded at room temperature and at 0.01-cm^−1 resolution using a Fourier transform spectrometer. Halfwidths and pressure shifts were determined for over 180 transitions belonging to J″ values of ?16. Comparisons of air-broadened halfwidths and pressure-induced line shifts made for identical transitions in the ν_4 bands of ^12CH_4 and ^13CH_4 have shown that ^13CH_4 air-broadened halfwidths are ~5% smaller than the corresponding ^12CH_4 halfwidths, and the pressure shifts for ^13CH_4 lines are ~5–15% larger than those for ^12CH_4.

Data from the Halogen Occultation Experiment (HALOE) provide the first opportunity to examine solar center-to-limb relative intensity measured exoatmospherically at wavelengths from 2.4 to 10 µm. The data were obtained from limb-to-limb scans across the solar equator on days of very low activity in May 1994. Coefficients for a function describing limb darkening are obtained at eight infrared wavelengths using a nonlinear least-squares fitting technique. Relative intensities produced by the limb-darkening functions are precise to 0.1% (2s). From the limb-darkening coefficients, it is possible to calculate temperature information about the photosphere. At each of the eight HALOE wavelengths, the brightness temperature from the flux, Tbdisk(?), and the temperature as a function of monochromatic optical depth, T(t?), are determined and normalized using Kondratyev et al. (1965) and calibrated Pierce (1954) central intensity measurements. The two temperature quantities are compared with the predictions of Vernazza, Avrett, and Loeser's (1976) model M, and in general there is good agreement. The largest differences occur between 2.4 and 3 µm and suggest that the central intensities used in this spectral region are low.

Seven basic fluorochromes with varying specificities were used to stain the large squamous epithelial cells isolated from the larval salivary glands of Megaselia scalaris (Phoridae). Although the EDTA-based method selected for isolating the cells produced permeabilization and a loss of viability of the cells, consistent results were obtained with the various fluorochromes. The “classical” pattern of green nuclear and red cytoplasmic fluorescence observed in cells stained with acridine orange could be changed to green cytoplasmic and red nuclear fluorescence by pretreatment with RNase. The predominantly cytoplasmic and nucleolar fluorescence obtained with pyronine Y could be changed to mainly nuclear fluorescence by RNase pretreatment. The other five fluorochromes tested were not affected appreciably by extraction with RNase. Quinacrine mustard, dicarbocyanine (DiOC6(3)), and rhodamine 123 produced primarily cytoplasmic and nucleolar fluorescence, while nile red revealed mainly cytoplasmic lipid droplets. Phosphine 3R initially stained lipid droplets but very rapidly redistributed throughout the cytoplasm and nucleus. Because of their large size, flatness, and content of histochemically demonstrable components, the cells of Megaselia are especially appropriate for use as “optical objects” or controls in various studies. New methods of isolating the cells, however, will be needed to prevent permeabilization and loss of viability of the cells.

BUG6 is a temperature-sensitive cell division mutant which forms filaments at the nonpermissive temperature. Synthesis of the maltose- and galactose-binding protein-dependent transport systems is also temperature sensitive in BUG6. Using operon and protein fusions of the maltose transport genes to lacZ, we observed that the temperature-sensitive control of the maltose transport system in BUG6 occurs at the transcriptional level. By P1-mediated transductions, we found that BUG6 contains two independent temperature-sensitive mutations. One maps between 2 and 3 min on the Escherichia coli linkage map, in close proximity to the fts-envA region. This mutation is responsible for temperature-sensitive cell division. The other mutation maps at 73 min in crp, the structural gene of the catabolite activator protein. The latter could be complemented by a hybrid plasmid carrying the wild-type crp as the only gene on a 0.9-kilobase HindIII-AluI restriction fragment. The mutation in crp alone was found to be responsible for the temperature-sensitive synthesis of the maltose transport system. Although it causes a complete block of transcription of the maltose transport genes at 41 degrees C, this mutation had only a marginal effect on the transcription of the lac operon.

Air-broadened halfwidths of eighteen transitions in the ν_6 band of H_2O_2 have been determined at room temperature from high resolution laboratory spectra recorded with a tunable diode laser system. The measured transitions occur in the 1252–1291-cm^−1 region. For these eighteen transitions, the measured halfwidths range from 0.0923 to 0.1155 cm^−1 atm^−1.

A personal narrative is presented which explores the author's experience of competing in the Western States Endurance Run.

Highlights activities that are being sponsored by the Soil Conservation Service in Minnesota in honor of African-American History Month. Examples include special presentations, an African-American history question-of-the-week during February and showing of the video `Eye to Eye.'