93 research outputs found
Culex (Melanoconion) hutchingsae Talaga & Gendrin 2022, n. sp.
No full textCulex (Melanoconion) hutchingsae Talaga, n. sp. Zoobank LSID: urn:lsid:zoobank.org:act: 359A3B9D-819C-4BA0-86C7-AC3E46513ECC BIN: BOLD:AEE6759. Culex (Melanoconion) coppenamensis Form 2 (in part) of Sallum & Hutchings (2003) (illustration of gonostylus, species distribution). Male. Habitus not examined. Genitalia (Fig. 3A‒G): Tergum VIII with a shallow V-shaped emargination separating the 2 lateral lobes, with longer setae forming a lateral concentrated setal group. Tergum IX with 2 distinct lobes, shape as shown in Fig. 3F, bearing 33‒35 setae, outer basal setae clearly longer than the others. Gonocoxite globose, outer margin convex, inner margin nearly straight; ventrolateral setae strongly developed; ventromesal surface with small, scattered setae from base to level of distal division of subapical lobe; lateral surface with a well-developed patch of long setae (lsp) at level of subapical lobe, setae longer ventrally; proximal part of ventrolateral surface with numerous scales. Subapical lobe clearly divided into 2 divisions. Proximal division moderately long, columnar, not clearly divided into 2 arms, proximal arm conspicuously shorter than distal arm, each arm bearing 1 long, robust, sinuous, apically hooked seta (setae a and b), both setae equivalent in length and width; a patch of short setae inserted mesally at base of distal surface. Distal division subdivided into inner and outer arms; inner arm with 2 apical setae, 1 long hooked seta (h) and 1 shorter, narrow, saber-like seta (s) inserted in a small tubercle at base of seta h, both h and s arise from separate tubercles at proximal side, 3 or 4 subapical setae, 1 long, wide, apically curved saberlike seta (s) and 3 indistinct, narrow, appressed flattened setae (f) inserted in small tubercles at base of seta s; outer arm long, nearly straight with 1 foliform seta (l) at apex, seta l strongly enlarged, almost symmetrical, striate at base with a well-developed basal expansion. Gonostylus short, strong, with a patch of long spicules at midlength on dorsal surface, distal 0.5 widened and abruptly tapering to apex in lateral view, bearing a conspicuous subapical crest on ventral side restricted to widest part; gonostylar claw long, leaf-like, 2 setae on dorsal side before gonostylar claw, distal seta slightly larger and longer than proximal seta. Phallosome with lateral plates and aedeagal sclerites equivalent in length; aedeagal sclerite narrow, curved in lateral view with anterior margin thickened and sclerotized, narrowly fused to base of lateral plate; distal part of lateral plate with median, sternal and tergal processes; apical median process conical with apex produced into a point tergad, tergal margin of apical process concave; apical sternal process short, somewhat hook-like, pointed, curved laterally; apical tergal process elongate, shorter than apical median process, pointed and directed dorsolaterally; base of lateral plate with short tergal process; aedeagal sclerite not connected by dorsal aedeagal bridge. Proctiger elongate; paraproct narrowed distally, expanded basally, crown a row of about 14 or 15 short simple blades. Cercal sclerite long and narrow with 2 or 3 cercal setae. Basal plate and paramere as figured. Tergum X somewhat rectangular in outline, rounded at apex. Etymology. This species is dedicated to Rosa Sá Gomes Hutchings for her valuable work on the diversity of mosquitoes in the Brazilian Amazon (e.g. Hutchings et al. 2005, 2010, 2013, 2018, 2020), and particularly on species allied to Culex coppenamensis Bonne-Wepster & Bonne, 1920, published in Sallum & Hutchings (2003) and Hutchings & Sallum (2008). Bionomics. Very little is known about the bionomics of Cx. hutchingsae. Immature stages were collected among roots and dead leaves at the edge of a large ground pool in rainforest (Fig. 5A). Water was highly brown-coloured with dissolved plant substances, acidic (pH = 5.9), moderately warm (26.4°C) and with a conductivity of 390 µS/ cm. Immature stages of Cx. hutchingsae were collected together with Anopheles (Anopheles) punctimacula Dyar & Knab, 1906a, Cx. (Mel.) rabelloi Forattini & Sallum, 1987 and Cx. (Mel.) serratimarge Root, 1927b. Distribution. Culex hutchingsae is known from the type locality and Gare Tigre, French Guiana (Fig. 1A). The latter is located at 45 km north-northeast from the type locality, but this area has been flooded since 1994 following the construction of the Petit Saut dam. Specimens of Cx. hutchingsae collected at Gare Tigre on 30 October 1945 were initially identified as Cx. coppenamensis by Floch (1946) and Floch & Abonnenc (1947). More recently, they were regarded as Cx. coppenamensis Form 2 by Sallum & Hutchings (2003) and as Cx. coppenamensis by Talaga et al. (2021). Type material. Holotype: Adult male in 96% ethanol with dissected genitalia mounted on a microscope slide and associated pupal and larval exuviae in 70% ethanol (specimen numbers ST1#01727, BOLD: FGMOS2912- 22), FRENCH GUIANA: Montagnes de la Trinité, Mare Aya (53.41445° W, 4.60289° N, 120 m above sea level), 5-XI-2020, S. Talaga, IPG. Paratypes: Two individualized adult males in 96% ethanol with dissected genitalia mounted on separate microscope slides and individualized associated pupal exuviae in 70% ethanol (specimen numbers ST1#01729, BOLD: FGMOS2914-22 and ST1#01734, BOLD: FGMOS2919-22), same collection data as the holotype, IPG. Other material examined. One male genitalia mounted on a microscope slide (IPG1#00639) and associated pupal and larval exuviae mounted on a separate microscope slide (IPG1#00603), original specimen number N°817 (17A), FRENCH GUIANA: Gare Tigre, 30-X-45, E. Abonnenc, IPG.Published as part of Talaga, Stanislas & Gendrin, Mathilde, 2022, Three new species of Culex (Melanoconion) (Diptera: Culicidae) from French Guiana based on morphological and molecular data, pp. 177-189 in Zootaxa 5205 (2) on pages 181-183, DOI: 10.11646/zootaxa.5205.2.5, http://zenodo.org/record/730585
A Swiss Army Knife to Cut Malaria Transmission
No full textInternational audienceThe mosquito microbiota is known to naturally limit malaria transmission, acting directly on parasites and via effects on mosquito immunity and fitness. Using genetically modified bacteria and mosquitoes, two studies uncover new potential of this multipotent prospective tool to reduce disease transmission
Fiction and Reality in HBO’s Treme: A Narrative Alchemy at the Service of Political Truth
No full textAuthor of the television drama The Wire, David Simon with Eric Overmyer launched a new series entitled Treme on the American channel HBO in April, 2010. Located in the heart of New Orleans, Tremé is a neighborhood known for its unique cultural, social, and historical context. It is the oldest African American neighborhood in the United States, the birthplace of the Black civil right movement in the South and the home of Jazz. Categorized as a drama by David Simon, the series is a work of fiction. Yet it also depicts day-to-day life in New Orleans in the aftermath of Katrina, referencing real events, real people, real places, and real cultural symbols. Relying on the work of Schaeffer and Esquenazi, this article links fiction to reality with an analysis of historical truths though fictional characters’ narratives. With this methodology, we examine the film-makers’ perspective, and uncover the political intentionality of the series as an act of denunciation against the dysfunctions of the local, state, and federal institutions in responding to the Katrina catastrophe. The political message of the series is also an act of testimony and homage about the daily lives and struggles of New Orleanians in a post-Katrina era.Auteur du drame télévisé The Wire, David Simon a lancé avec Eric Overmyer une nouvelle série intitulée Treme sur la chaîne américaine HBO en avril 2010. Situé au cœur de la Nouvelle Orléans, Tremé est un quartier connu pour son contexte unique sur les plans culturels, social et historique. C’est le quartier afro-américain le plus ancien aux États-Unis, le lieu de naissance du mouvement pour les droits civiques des noirs dans le Sud et le pays du Jazz. Catégorisé comme un drame par David Simon, la série est une œuvre de fiction. Or, elle représente la vie quotidienne dans la Nouvelle Orléans après l’ouragan Katrina, faisant référence à de vrais événements, de vraies personnes, de vrais endroits et de vrais symboles culturels. S’appuyant sur les travaux de Schaeffer et Esquenazi, cet article relie la fiction à la réalité avec une analyse des vérités historiques à travers les récits fictifs des personnages. Avec cette méthodologie, nous examinons la perspective des réalisateurs et dévoilons l’intentionnalité politique de la série comme un acte de dénonciation du dysfonctionnement des institutions municipales, régionales et fédérales en réponse à la catastrophe de Katrina. Le message politique de la série est aussi un acte de témoignage et d’hommage aux vies et aux luttes des habitants de la Nouvelle-Orléans dans l’ère post-Katrina
Different types of whistler mode chorus in the equatorial source region
No full textInternational audienceThe Time History of Events and Macroscale Interactions during Substorms-D spacecraft crossed an active equatorial source region of whistler mode chorus rising tones on 23 October 2008. Rising tones are analyzed in terms of spectral and polarization characteristics, with special emphasis on wave normal angles. The latter exhibit large variations from quasi-parallel to oblique, even within single bursts, but seem to follow a definite pattern, which enables an unambiguous classification into five different groups. Furthermore, we discuss the frequently observed splitting of chorus bursts into a lower and an upper band around one half of the local electron cyclotron frequency. At chorus frequencies close to the gap, we find significantly lowered wave planarities and a tendency of wave normal angles to approach the Gendrin angle
Using dimers to measure biosignatures and atmospheric pressure for terrestrial exoplanets
No full textWe present a new method to probe atmospheric pressure on Earth-like planets using (O-O) dimers in the near-infrared. We also show that dimer features could be the most readily detectable biosignatures for Earth-like atmospheres and may even be detectable in transit transmission with the James Webb Space Telescope (JWST). The absorption by dimers changes more rapidly with pressure and density than that of monomers and can therefore provide additional information about atmospheric pressures. By comparing the absorption strengths of rotational and vibrational features to the absorption strengths of dimer features, we show that in some cases it may be possible to estimate the pressure at the reflecting surface of a planet. This method is demonstrated by using the O A band and the 1.06 μm dimer feature, either in transmission or reflected spectra. It works best for planets around M dwarfs with atmospheric pressures between 0.1 and 10 bar and for O volume mixing ratios above 50% of Earth's present-day level. Furthermore, unlike observations of Rayleigh scattering, this method can be used at wavelengths longer than 0.6 μm and is therefore potentially applicable, although challenging, to near-term planet characterization missions such as JWST. We also performed detectability studies for JWST transit transmission spectroscopy and found that the 1.06 and 1.27 μm dimer features could be detectable (SNR>3) for an Earth analogue orbiting an M5V star at a distance of 5 pc. The detection of these features could provide a constraint on the atmospheric pressure of an exoplanet and serve as biosignatures for oxygenic photosynthesis. We calculated the required signal-to-noise ratios to detect and characterize O monomer and dimer features in direct imaging-reflected spectra and found that signal-to-noise ratios greater than 10 at a spectral resolving power of R=100 would be required.Peer reviewe
He+ dominance in the plasmasphere during geomagnetically disturbed periods: 1. Observational results
No full textObservations made by the DMSP 1710 satellite during the recovery phase from geomagnetic disturbances in June 1991 show regions of He+ dominance around 830 km altitude at 09:00 MLT. These regions are co-located with a trough in ionisation observed around 55degrees in the winter hemisphere. Plasma temperature and concentration observations made during the severe geomagnetic storm of 24 March 1991 are used as a case study to determine the effects of geomagnetic disturbances along the orbit of the F10 satellite. Previous explanations for He+ dominance in this trough region relate to the part of the respective flux tubes that is in darkness. Such conditions are not relevant for this study, since the whole of the respective flux tubes are sunlit. A new mechanism is proposed to explain the He+ dominance in the trough region. This mechanism is based on plasma transport and chemical reaction effects in the F-region and topside ionosphere, and on the time scales for such chemical reactions. Flux tubes previously depleted by geomagnetic storm effects refill during the recovery phase from the ionosphere as a result of pressure differences along the flux tubes. Following a geomagnetic disturbance, the He+ ion recovers quickly via the rapid photoionisation of neutral helium, in the F-region and the topside. The recovery of the O+ and H+ ions is less rapid. This is proposed as a result of the respective charge exchange reactions with neutral atomic hydrogen and oxygen. Preliminary model calculations support the proposed mechanism
Efficacité et risques inhérents à la décolonisation digestive par streptomycine orale chez les porteurs d’entérocoques résistants aux glycopeptides
No full textHigh-frequency Alfven waves in multi-ion coronal plasma : observational implications
No full textWe investigate the effects of high-frequency (of order ion gyrofrequency) Alfvén and ion-cyclotron waves on ion emission lines by studying the dispersion of these waves in a multi-ion coronal plasma. For this purpose we solve the dispersion relation of the linearized multifluid and Vlasov equations in a magnetized multi-ion plasma with coronal abundances of heavy ions. We also calculate the dispersion relation using nonlinear one-dimensional hybrid kinetic simulations of the multi-ion plasma. When heavy ions are present the dispersion relation of parallel propagating Alfvén cyclotron waves exhibits the following branches (in the positive Ω − k quadrant): right-hand polarized nonresonant and left-hand polarized resonant branch for protons and each ion. We calculate the ratio of ion to proton velocities perpendicular to the direction of the magnetic field for each wave modes for typical coronal parameters and find strong enhancement of the heavy ion perpendicular fluid velocity compared with proton perpendicular fluid velocity. The linear multifluid cold plasma results agree with linear warm plasma Vlasov results and with the nonlinear hybrid simulation model results. In view of our findings we discuss how the observed nonthermal line broadening of minor ions in coronal holes may relate to the high-frequency wave motions
Timescales for electron quasi-linear diffusion by parallel and oblique lower-band chorus waves
No full textInternational audience[1] The loss of relativistic electrons from the Earth's radiation belts can be described in terms of the quasi-linear pitch angle diffusion by cyclotron-resonant waves, provided that their frequency spectrum is broad enough. Chorus waves at large wave-normal angles with respect to the magnetic field are often present in CLUSTER and THEMIS measurements in the outer belt at moderate to high latitudes. An approximate analytical formulation of diffusion coefficients has been derived in the low-frequency limit, leading to a simplified analytical expression of diffusion coefficients and lifetimes for energetic trapped electrons. Large values of the wave-normal angles between the Gendrin and resonance angles are shown to induce important increases in diffusion, thereby strongly reducing the particle lifetimes (by almost two orders of magnitude). The analytical diffusion coefficients and lifetimes obtained here are found to be in a good agreement with full numerical calculations based on CLUSTER chorus waves measurements in the outer belt for electron energies ranging from 100 keV to 2 MeV. Such very oblique chorus waves could contribute to a predominantly perpendicular anisotropy of the global equatorial electron population on the dayside and to a relative isotropization at low energy under disturbed conditions. It is also suggested that they might play a significant role in pulsating auroras
Selecting the geology filter wavelengths for the ExoMars Panoramic Camera instrument
No full textThe Panoramic Camera (PanCam) instrument will provide surface remote sensing data for the ExoMars mission. A combination of wide-angle stereo, multispectral, and high resolution imagery will generate contextual geological information to help inform which scientific targets should be selected for drilling and analysis. One component of the PanCam dataset is narrowband multispectral imaging in the visible to near infrared, which utilises a dedicated set of 12 “geology” filters of predetermined wavelength and bandwidth to view the terrain, and provide information on composition and putative mineralogy. The centre wavelengths and bandwidths of these filters were optimised to account for the highly diverse mineralogical terrains the ExoMars rover will hopefully encounter. Six new alternative test filter sets were created, each optimised for the detection of either: sulfates, phyllosilicates, ferric oxides, mafic silicates, iron absorptions, and minor hydration absorptions. These six filter sets were cross-tested using database mineral reflectance spectra and Mars analogue rock multispectral data to find the best performing filter set. Once selected, the bandwidths of this filter set were also optimised. The filter set optimised to ferric oxide minerals was able to most accurately represent rock multispectral data, as well as capture subtle spectral features of hydrated minerals, including sulfates, phyllosilicates, and carbonates. These filters differ from those used on past missions (e.g., Pathfinder, Mars Exploration Rover) and represent the next evolutionary stage in PanCam instrument development. When compared to past filter sets, the updated ExoMars filters capture rock and mineral spectral data more effectively, enhancing the ability of the ExoMars PanCam to detect lithological and compositional variation within an outcrop
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