High-resolution far-infrared and sub-millimetre spectroscopy of water lines is an important tool to understand the physical and chemical properties of cometary atmospheres. We present observations of ...several rotational ortho- and para-water transitions in comet C/2008 Q3 (Garradd) performed with HIFI on Herschel. These observations have provided the first detection of the 2_{12}-1_{01} (1669 GHz) ortho and 1_{11}-0_{00} (1113 GHz) para transitions of water in a cometary spectrum. In addition, the ground-state transition 1_{10}-1_{01} at 557 GHz is detected and mapped. By detecting several water lines quasi-simultaneously and mapping their emission we can constrain the excitation parameters in the coma. Synthetic line profiles are computed using excitation models which include excitation by collisions, solar infrared radiation, and radiation trapping. We obtain the gas kinetic temperature, constrain the electron density profile, and estimate the coma expansion velocity by analyzing the map and line shapes. We derive water production rates of 1.7-2.8 x 10^{28} s^{-1} over the range r_h = 1.83-1.85 AU.
Needles from phosphorus deficient seedlings of Pinus radiata D. Don grown for 8 weeks at either 330 or 660 microliters CO2 per liter displayed chlorophyll a fluorescence induction kinetics ...characteristic of structural changes within the thylakoid chloroplast membrane, i.e. constant yield fluorescence ($\text{F}_{\text{O}}$) was increased and induced fluorescence ($\text{F}_{\text{P}}-\text{F}_{\text{I}}/\text{F}_{\text{O}}$) was reduced. The effect was greatest in the undroughted plants grown at 660 μl $\text{CO}_{2}\ \text{L}^{-1}$. By week 22 at 330 μl $\text{CO}_{2}\ \text{L}^{-1}$ acclimation to P deficiency had occurred as shown by the similarity in the fluorescence characteristics and maximum rates of photosynthesis of the needles from the two P treatments. However, acclimation did not occur in the plants grown at 660 μl $\text{CO}_{2}\ \text{L}^{-1}$. The light saturated rate of photosynthesis of needles with adequate P was higher at 660 μl $\text{CO}_{2}\ \text{L}^{-1}$ than at 330 μl $\text{CO}_{2}\ \text{L}^{-1}$, whereas photosynthesis of P deficient plants showed no increased when grown at the higher CO2 concentration. The average growth increase due to CO2 enrichment was 14% in P deficient plants and 32% when P was adequate. In drought stressed plants grown at 330 μl $\text{CO}_{2}\ \text{L}^{-1}$, there was a reduction in the maximal rate of quenching of fluorescence ($\text{R}_{\text{Q}}$) after the major peak. Constant yield fluorescence was unaffected but induced fluorescence was lower. These results indicate that electron flow subsequent to photosystem II was affected by drought stress. At 660 μl $\text{CO}_{2}\ \text{L}^{-1}$ this response was eliminated showing that CO2 enrichment improved the ability of the seedlings to acclimate to drought stress. The average growth increase with CO2 enrichment was 37% in drought stressed plants and 19% in unstressed plants.
We report on the initial analysis of Herschel/HIFI carbon monoxide (CO) observations of the Martian atmosphere performed between 11 and 16 April 2010. We selected the (7-6) rotational transitions of ...the isotopes ^{13}CO at 771 GHz and C^{18}O at 768 GHz in order to retrieve the mean vertical profile of temperature and the mean volume mixing ratio of carbon monoxide. The derived temperature profile agrees within less than 5 K with general circulation model (GCM) predictions up to an altitude of 45 km, however, show about 12-15 K lower values at 60 km. The CO mixing ratio was determined as 980 \pm 150 ppm, in agreement with the 900 ppm derived from Herschel/SPIRE observations in November 2009.
We report on the initial analysis of a Herschel/PACS full range spectrum of Neptune, covering the 51-220 micrometer range with a mean resolving power of ~ 3000, and complemented by a dedicated ...observation of CH4 at 120 micrometers. Numerous spectral features due to HD (R(0) and R(1)), H2O, CH4, and CO are present, but so far no new species have been found. Our results indicate that (i) Neptune's mean thermal profile is warmer by ~ 3 K than inferred from the Voyager radio-occultation; (ii) the D/H mixing ratio is (4.5+/-1) X 10**-5, confirming the enrichment of Neptune in deuterium over the protosolar value (~ 2.1 X 10**-5); (iii) the CH4 mixing ratio in the mid stratosphere is (1.5+/-0.2) X 10**-3, and CH4 appears to decrease in the lower stratosphere at a rate consistent with local saturation, in agreement with the scenario of CH4 stratospheric injection from Neptune's warm south polar region; (iv) the H2O stratospheric column is (2.1+/-0.5) X 10**14 cm-2 but its vertical distribution is still to be determined, so the H2O external flux remains uncertain by over an order of magnitude; and (v) the CO stratospheric abundance is about twice the tropospheric value, confirming the dual origin of CO suspected from ground-based millimeter/submillimeter observations.
Cette étude propose une analyse des différences et similitudes linguistiques dans la presse écrite traditionnelle et les médias participatifs en ligne afin d’évaluer dans quelle mesure la production ...et la diffusion en ligne peuvent modifier nos usages linguistiques. Les analyses effectuées se basent sur un large corpus (8 millions de mots) qui représente des modes d’expression et des degrés de subjectivité a priori différents.
On 19 Feb. 2016 nine Rosetta instruments serendipitously observed an outburst of gas and dust from the nucleus of comet 67P/Churyumov-Gerasimenko. Among these instruments were cameras and ...spectrometers ranging from UV over visible to microwave wavelengths, in-situ gas, dust and plasma instruments, and one dust collector. At 9:40 a dust cloud developed at the edge of an image in the shadowed region of the nucleus. Over the next two hours the instruments recorded a signature of the outburst that significantly exceeded the background. The enhancement ranged from 50% of the neutral gas density at Rosetta to factors >100 of the brightness of the coma near the nucleus. Dust related phenomena (dust counts or brightness due to illuminated dust) showed the strongest enhancements (factors >10). However, even the electron density at Rosetta increased by a factor 3 and consequently the spacecraft potential changed from ˜-16 V to -20 V during the outburst. A clear sequence of events was observed at the distance of Rosetta (34 km from the nucleus): within 15 minutes the Star Tracker camera detected fast particles (˜25 m sSUP-1/SUP) while 100 μm radius particles were detected by the GIADA dust instrument ˜1 hour later at a speed of ~6 m sSUP-1/SUP. The slowest were individual mm to cm sized grains observed by the OSIRIS cameras. Although the outburst originated just outside the FOV of the instruments, the source region and the magnitude of the outburst could be determined.
Lösch (2001) concluded that information on the ecophysiology of tropical mountain trees — key components for the understanding of the functional role of vegetation in these ecosystems — is entirely ...missing; therefore we concentrate on transpiration. Available knowledge on stands is almost exclusively from catchment studies (e.g. Bruijnzeel and Proctor 1995; see Chapter 12 in this volume), but types of “gully”, “slope” and “stunted” forests are found everywhere. To evaluate their contribution to water consumption and buffering in the landscape it is essential to characterize these forest types individually, here via up-scaling from sap flow measurements on individual trees to plot-scale. In this context it is important to know whether sap flow varies species-specifically (then many species have to be studied) or whether the size of individual plants, their life-forms, and associations with functional groups are more important (then only a few representative individuals need to be investigated).
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