658 research outputs found
High sensitivity Cavity Ring Down spectroscopy of 18O enriched carbon dioxide between 5850 and 7000 cm-1: Part III-Analysis and theoretical modeling of the 12C17O2, 16O12C17O, 17O12C18O, 16O13C17O and 17O13C18O spectra
More than 19,700 transitions belonging to 11 isotopologues of carbon dioxide
have been assigned in the room temperature absorption spectrum of highly 18O
enriched carbon dioxide recorded by very high sensitivity CW-Cavity Ring Down
spectroscopy between 5851 and 6990 cm-1 (1.71-1.43 \mum). This third and last
report is devoted to the analysis of the bands of five 17O containing
isotopologues present at very low concentration in the studied spectra:
16O12C17O, 17O12C18O, 16O13C17O, 17O13C18O and 12C17O2 (627, 728, 637, 738 and
727 in short hand notation). On the basis of the predictions of effective
Hamiltonian models, a total of 1759, 1786, 335, 273 and 551 transitions
belonging to 24, 24, 5, 4 and 7 bands were rovibrationally assigned for 627,
728, 637, 738 and 727, respectively. For comparison, only five bands were
previously measured in the region for the 728 species. All the identified bands
belong to the \deltaP=8 and 9 series of transitions, where P=2V1+V2+3V3 is the
polyad number (Vi are vibrational quantum numbers). The band-by-band analysis
has allowed deriving accurate spectroscopic parameters of 61 bands from a fit
of the measured line positions. Two interpolyad resonance perturbations were
identified
First observation of electric-quadrupole infrared transitions in water vapour
Molecular absorption of infrared radiation is generally due to ro-vibrational
electric-dipole transitions. Electric-quadrupole transitions may still occur,
but they are typically a million times weaker than electric-dipole transitions,
rendering their observation extremely challenging. In polyatomic or polar
diatomic molecules, ro-vibrational quadrupole transitions have never been
observed. Here, we report the first direct detection of quadrupole transitions
in water vapor. The detected quadrupole lines have intensity largely above the
standard dipole intensity cut-off of spectroscopic databases and thus are
important for accurate atmospheric and astronomical remote sensing
Reproduction and adaptation characteristics in D’man sheep
D’man breed (D) is found in the oasis of the subsaharian regions of Morocco and reared usually in sedentary type of management with small flocks (< 10 ewes). Preliminary field surveys showed that D is early maturing, prolific and aseasonal. Hence, a multidisciplinary research programme on D was started in 1974. This paper reports the findings of these studies and describes the approach used to (1) characterize and evaluate the performances of D in field and station, (2) study the physiological mechanism involved in its peculiar reproduction and production, (3) study the genetic basis of reproduction parameters, and (4) evaluate use of D in crossbreeding schemes to improve the productivity of other Moroccoan breeds. Results show that D is one of the rare breeds that is simultaneously early maturing, highly prolific and completely aseasonal. However, studies on water turnover and nitrogen recycling show that D is not well adapted to hot climate and poor nutrition. Its reproduction parameters are relatively independent of photoperiod and related to a low sensitivity to negative oestrogen feedback. D male is characterized by high libido and can be used for synchronizing oestruses through the »ram effect». Crossbreeding experiments with non-prolific sheep confirm the heritability of reproductive parameters. However, the genetic basis for these is not yet well known
Diversite floristique et valeur de conservation de la foret classee de Badenou (Korhogo, Cote d’Ivoire)
La présente étude a été initiée pour contribuer à la gestion durable de la forêt classée de Badénou. Elle a permis d’analyser les diversités floristiques, la structure de la végétation et d’estimer le stock de carbone séquestré dans les différents biotopes le long d’une chronoséquence de stades postculturaux au sein d’un système de forêt claire de Côte d’Ivoire. Un total de 241 espèces a été recensé dans l’ensemble du massif, dont 97 espèces (inventoriées dans les 30 parcelles) participent à la chronoséquence. Les 241 espèces étaient réparties en 184 genres et 53 familles, dont les plus importantes étaient les Fabaceae, les Rubiaceae et les Poaceae. La flore de cette aire protégée est aussi caractérisée par la présence des espèces à statut particulier dont une endémique ivoirienne. Ces travaux montrent également que les paramètres de composition et de structures des peuplements augmentent avec l’âge de la jachère. Le potentiel de stockage de carbone des différents biotopes rend compte de la participation de la forêt classée de Badenou à la réduction du CO2 atmosphérique dans cette région de la Côte d’Ivoire. Malheureuse, la forêt classée de Badenou subit encore d’énormes pressions anthropiques. Les efforts de conservation des espèces endémiques, rares et menacées d’extinction et de la forêt classée elle-même doivent être une priorité.
Mots-clés : Forêt claire, Jachères, Biodiversité, Changement climatique, Badenou
English Title: Floristic diversity and conservation value of the Badenou Classified Forest (Korhogo, Cote dIivoire)
This study was initiated to contribute to the sustainable management of the Badénou classified forest. It allowed to analyze the floristic diversities, the structure of the vegetation and estimate the carbon stock sequestered in the various biotopes along a chronosequence of post-cultural stages within a system of clear forest of Ivory Coast. A total of 241 species have been identified throughout the massif, of which 97 species (inventoried in the 30 plots) participate in the chronosequence. The 241 species were divided into 184 genus and 53 families, the most important of its were Fabaceae, Rubiaceae and Poaceae. The flora of this protected area is also characterized by the presence of special status species including an endemic Ivorian. This study also show that the parameters of stand composition and structure increase with the age of the fallow. The carbon storage potential of the different biotopes accounts for the participation of the Badénou classified forest in the reduction of atmospheric CO2 in this region of Ivory Coast. Unfortunately, the Badénou classified forest is still under enormous human pressure. Conservation efforts for endemic species, rare and endangered species and the classified forest itself must be a priority.
Keys words: Clear forest, Fallows, Biodiversity, Climate change, Badeno
Electric-quadrupole and magnetic-dipole contributions to the ν₂+ν₃ band of carbon dioxide near 3.3 µm
The recent detections of electric-quadrupole (E2) transitions in water vapor and magnetic-dipole (M1) transitions in carbon dioxide have opened a new field in molecular spectroscopy. While in their present status, the spectroscopic databases provide only electric-dipole (E1) transitions for polyatomic molecules (H_{2}O, CO_{2}, N_{2}O, CH_{4}, O_{3}…), the possible impact of weak E2 and M1 bands to the modeling of the Earth and planetary atmospheres has to be addressed. This is especially important in the case of carbon dioxide for which E2 and M1 bands may be located in spectral windows of weak E1 absorption. In the present work, a high sensitivity absorption spectrum of CO_{2} is recorded by Optical-Feedback-Cavity Enhanced Absorption Spectroscopy (OFCEAS) in the 3.3 µm transparency window of carbon dioxide. The studied spectral interval corresponds to the region where M1 transitions of the ν_{2}+ν_{3} band of carbon dioxide were recently identified in the spectrum of the Martian atmosphere. Here, both M1 and E2 transitions of the ν_{2}+ν_{3} band are detected by OFCEAS. Using recent ab initio calculations of the E2 spectrum of {12}^C^{16}O_{2}, intensity measurements of five M1 lines and three E2 lines allow us to disentangle the M1 and E2 contributions. Indeed, E2 intensity values (on the order of a few 10^{–29} cm/molecule) are found in reasonable agreement with ab initio calculations while the intensity of the M1 lines (including an E2 contribution) agree very well with recent very long path measurements by Fourier Transform spectroscopy. We thus conclude that both E2 and M1 transitions should be systematically incorporated in the CO_{2} line list provided by spectroscopic databases
Rumen ecology research planning. Proceedings of a workshop
This workshop was conducted to identify and prioritise areas of rumen ecology which are promising for their potential impact on improving nutrition status of tropical ruminants, to develop a rumen ecology research programme for ILRI based on relevance to developing countries and ILRI's comparative advantage vis-a-vis other institutions, to identify potential collaborators in advanced research institutes, and to define model(s) of collaboration. Major topics of discussion include - potential application of rumen ecology manipulation to animal nutrition in developing countries, state of art in manipulation of the rumen microbial ecosystem, and state of art in bioengineering of rumen microorganisms
Antifungal activities of the essential oil extracted from the tea of savanna (Lippia multiflora) in Côte d’Ivoire
The objective of this study was to evaluate the antifungal potency of the essential oil of tea of savanna (Lippia multiflora) on three fungal strains. The essential oil is extracted of Lippia multiflora by steam distillation and the antifungal activity in vitro was investigated on Apergillus flavus, Asperguillus Niger and Fusarium sp species. This activity was realized by incorporation of the plant extract in Sabouraud medium prepared by a double dilution. The study revealed a sensitivity of these three species to the essential oil extracted from Lippia multiflora. It has been observed, in a descending order of sensitivity, a minimum fungicidal concentration (MFC) of 2.08 ± 0.58 µl / ml with Aspergillus flavus; 4.16 ± 1.17 µl / ml with Aspergillus Niger and 8.33 ± 2.35 µl / ml with Fusarium sp. The antifungal potency of the essential oil extracted from Lippia multiflora, allows considering its use as a novel approach in the field of integrated management of cereal stocks in post-harvest.Keywords: Essential oil, Lippia multiflora, Antifungal, Aspergillus, Fusarium
Effet antihypertensif d\'un extrait aqueux d\'écorce de tronc de Parkia biglobosa (mimosaceae) sur la pression artérielle de lapin.
Un extrait aqueux des écorces de tronc de Parkia biglobosa (EAPB), à des concentrations comprises entre 1,18 et 18, 93 mg/kg de poids corporel, induit une hypotension dose dépendante sur la pression artérielle de lapin. L'interaction Adrénaline - EAPB a révélé une réduction significative (
L'infection par le VIH chez les femmes en âge de procréer à Sassandra (Côte d'Ivoire)
Le travail, réalisé en 1988-1989, a consisté à comparer les caractéristiques socio-démographiques des femmes en âge de procréer (15-49 ans) d'une sous-préfecture rurale de Côte d'Ivoire (Sassandra) avec leur statut sérologique VIH afin de dégager des variables explicatives de cette séropositivité. Il n'a pas été possible de tester que 521 femmes sur les 1084 qui constituaient la population de départ, mais les deux sous-populations ne diffèrent que par les lieux de naissance et de résidence. La séropositivité tréponémique est élevée, de façon homogène. Pour la séropositivité du VIH, le taux global de séropositivité est de 6,1 plus ou moins 0,02 %, soit un taux intermédiaire (différences non significatives) entre ceux trouvés lors de l'enquête nationale en zone rurale (4,9 %) et en zone urbaine (7,3 %). Ce taux de séropositivité est lié au lieu de naissance (même après ajustement sur le taux de présentation); les femmes nées dans la région sont plus souvent positives que les autres et les femmes nées dans les villages plus souvent que celles nées en ville (p = 0,005 et 0,02). En revanche, les femmes mariées sont moins souvent positives que les femmes non mariées et que celles vivant en union libre (p = 0,02 et 0,0005); la polygamie semble apporter une certaine protection envers le VIH par rapport à la monogamie. Enfin les femmes séropositives ont eu plus souvent des enfants mort-nés et moins souvent des enfants décédés que les femmes séronégatives (p = 0,02 et 0,03). Il est proposé de renforcer les activités de surveillance prénatale et de les renforcer surtout en zone rurale pour prévenir de nouvelles infections par le VIH. (Résumé d'auteur
Pluto's lower atmosphere structure and methane abundance from high-resolution spectroscopy and stellar occultations
Context: Pluto possesses a thin atmosphere, primarily composed of nitrogen,
in which the detection of methane has been reported.
Aims: The goal is to constrain essential but so far unknown parameters of
Pluto's atmosphere such as the surface pressure, lower atmosphere thermal
stucture, and methane mixing ratio.
Methods: We use high-resolution spectroscopic observations of gaseous
methane, and a novel analysis of occultation light-curves.
Results: We show that (i) Pluto's surface pressure is currently in the 6.5-24
microbar range (ii) the methane mixing ratio is 0.5+/-0.1 %, adequate to
explain Pluto's inverted thermal structure and ~100 K upper atmosphere
temperature (iii) a troposphere is not required by our data, but if present, it
has a depth of at most 17 km, i.e. less than one pressure scale height; in this
case methane is supersaturated in most of it. The atmospheric and bulk surface
abundance of methane are strikingly similar, a possible consequence of the
presence of a CH4-rich top surface layer.Comment: AA vers. 6.1, LaTeX class for Astronomy & Astrophysics, 9 pages with
5 figures Astronomy and Astrophysics Letters, in pres
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