Calibration of quasi-static aberrations in exoplanet direct-imaging instruments with a Zernike phase-mask sensor

Context. Several exoplanet direct imaging instruments will soon be in operation. They use an extreme adaptive optics (XAO) system to correct the atmospheric turbulence and provide a highly-corrected beam to a near-infrared (NIR) coronagraph for starlight suppression. The performance of the coronagraph is however limited by the non-common path aberrations (NCPA) due to the differential wavefront errors existing between the visible XAO sensing path and the NIR science path, leading to residual speckles in the coronagraphic image. Aims. Several approaches have been developed in the past few years to accurately calibrate the NCPA, correct the quasi-static speckles and allow the observation of exoplanets at least 1e6 fainter than their host star. We propose an approach based on the Zernike phase-contrast method for the measurements of the NCPA between the optical path seen by the visible XAO wavefront sensor and that seen by the near-IR coronagraph. Methods. This approach uses a focal plane phase mask of size {\lambda}/D, where {\lambda} and D denote the wavelength and the telescope aperture diameter, respectively, to measure the quasi-static aberrations in the upstream pupil plane by encoding them into intensity variations in the downstream pupil image. We develop a rigorous formalism, leading to highly accurate measurement of the NCPA, in a quasi-linear way during the observation. Results. For a static phase map of standard deviation 44 nm rms at {\lambda} = 1.625 {\mu}m (0.026 {\lambda}), we estimate a possible reduction of the chromatic NCPA by a factor ranging from 3 to 10 in the presence of AO residuals compared with the expected performance of a typical current-generation system. This would allow a reduction of the level of quasi-static speckles in the detected images by a factor 10 to 100 hence, correspondingly improving the capacity to observe exoplanets.Comment: 11 pages, 14 figures, A&A accepted, 2nd version after language-editor correction

Obstetrical complications among adolescent girls at the maternity ward of Ignace Deen National Hospital

Background: The objective of this study was to highlight obstetrical complications that occurred among adolescent girls who delivered at the ward and to identify factors associated with the occurrence of such complications.Methods: This was a prospective study of descriptive and analytical type extending over a period of one year from September 1, 2016 to August 31, 2017 carried out at the maternity ward of Ignace Deen National Hospital at Conakry Teaching Hospital (CHU). It covered a continuous series of 1034 deliveries among adolescent girls.Results: The frequency of childbirth among adolescent girls was 16.7%. The main complications identified were dystocia, severe preeclampsia, eclampsia, retroplacental hematoma, placenta previa, uterine rupture, severe anemia, postpartum hemorrhage and puerperal endometritis. These complications occurred among adolescent girls aged 18 to 19, christian, skin and pelvic bones secondary school or university students. Factors associated with such complications were the marital status (p=0.010), the gestational age (p=0.012), the number of prenatal consultations (p=0.001), the place of prenatal consultation (p=0.001), the reason for admission (p=0.000) and the mode of admission (p=0.000).Conclusions: Childbirth among adolescent girls is frequent in this context; complications are numerous but they are preventable in the vast majority of cases

Surgical intervention on uterine fibromyoma in a country with limited resources: case of the gynaecology-obstetrics department of the Communal Medical Centre of Ratoma Conakry - Guinea

Background: In developing countries, treatment of uterine fibromyoma is confronted with numerous problems, namely: financial inaccessibility to the proposed treatments, fear of surgery and the weakness of the technical platform. The objectives of the study were to calculate the frequency of uterine fibromyomas, describe the socio-demographic characteristics of patients, identify the main clinical data and to describe the modalities of surgical management.Methods: It was a mixed descriptive study, cumulative over a period of 5 years (60 months) with data collection in two phases: a 4-year retrospective study from January 1, 2015 to December 31, 2018 and a 1-year prospective study from January 1, 2019 to December 31, 2019.Results: Authors collected 135 cases of uterine fibromyomas operated on out of a total of 260 cases of gynaecological pathologies, i.e. a frequency of 51.92%. Nulliparous women were the most concerned (45.18%), and women who attended school (60%) and those who did not attend school (40%). Women at home and housewives accounted for 42.20% and 54.07% respectively. Clinically, the circumstances of discovery were dominated by menometrorrhagia and menorrhagia respectively 77.77% and 68.14%. The large uterus was the most frequent physical sign found in 96.29% of cases. Uterine fibromyomas were recorded in 86.6% of cases in women with genital activity. The operative indications were dominated by the large polymyomatous uterus (64.44%), followed by hemorrhagic fibroma (18.52%) The surgical treatment was conservative in 92.60%. The total hysterectomy was performed in 7.40. Lethality was 1.4%.Conclusions: The surgical management of fibroids contrasts conservative treatment (myomectomy) with radical treatment (hysterectomy) with multiple possible approaches (hysteroscopy, vaginal surgery, laparoscopy or laparotomy). In this context, only laparotomy was possible due to lack of equipment. Laparoscopy and hysteroscopy equipment are necessary for less invasive surgery

Natural polymorphism in the thrombospondin-related adhesive protein of Plasmodium falciparum

We have developed a typing system using natural sequence variation in the thrombospondin-related adhesive protein (TRAP) gene of Plasmodium falciparum. This method permits a haplotype to be assigned to any particular TRAP gene. We have applied this method to a hospital-based, case control-study in Mali. Previous sequence variation and conservation in TRAP has been confirmed. Particular TRAP haplotypes can be used as geographic hallmarks. Because of the high level of conflict between characters, we have examined the phylogenetic relationships between parasites using a network approach. Having received patient samples from urban and periurban areas of Bamako, the majority of haplotypes were closely related and distinct from TRAP sequences present in other continents. This suggests that the structure of TRAP can only tolerate a limited number of sequence variations to preserve its function but that this is sufficient to allow the parasite to evade the host's immune system until a long-lived immune response can be maintained. It may also reflect host genetics in that certain variants may escape the host immune response more efficiently than others. For vaccine design, sequences from the major regional variants may need to be considered in the production of effective subunit vaccines

Mixed matrix PVDF membranes with in-situ synthesized PAMAM dendrimer- like particles: A new class of sorbents for Cu(II) recovery from aqueous solutions by ultrafiltration

A one-pot method for the preparation of a new family of mixed matrix polyvinylidene fluoride (PVDF) membranes with in-situ synthesized poly(amidoamine) [PAMAM] particles is described. The key feature of this membrane preparation method is the in-situ synthesis of PAMAM dendrimer-like particles in the dope solutions prior to membrane casting using low-generation dendrimers with terminal primary amine groups (G0 and G1-NH2) as precursors and epichlorohydrin (ECH) as cross-linker. By using a combined thermally induced phase separation (TIPS) and non-solvent induced phase separation (NIPS) casting process, a new family of asymmetric PVDF ultrafiltration membranes with (i) neutral and hydrophilic surface layers of average pore diameters of 22−45 nm, (ii) high loadings (∼48 wt %) of dendrimer-like PAMAM particles with average diameters of ∼1.3−2.4 μm, and (iii) matrices with sponge-like microstructures characteristic of membranes with strong mechanical integrity were successfully prepared. Preliminary experiments show that these new mixed matrix PVDF membranes can serve as reusable high capacity sorbents for Cu(II) recovery from aqueous solutions by ultrafiltration

Etude des politiques relatives aux stratégies de gestion de la chimiorésistance dans le cadre de la lutte contre la trypanosomose en Afrique de l'Ouest: cas du Mali

Discussion sur l’etude des politiques relatives aux stratégies de gestion de la chimiorésistance dans le cadre de la lutte contre la trypanosomose en Afrique de l’Ouest, Mali. Le projet a pour objectif d’assurer l’efficacité des trypanocides comme une composante effective des strategies intégrées et améliorées de contrôle de Ia trypanosomose animale dans Ia region ouest-africaine. Pour atteindre cet objectif, des organisations nationales de recherche et de developpement, des institutions internationales et régionales de recherche, et des universités allemandes travaillent en partenariat afin de développer aux niveaux local et regional des strategies de reduction de risque de Ia chimiorésistance. L’accent est mis principalement sur l‘information et des supports techniques aux paysans, aux prestataires de service en sante animale, aux vétérinaires professionnels et aux décideurs politiques. Les informations et supports techniques ont pour but de promouvoir Ia lutte intégrée et l’utilisation rationnelle des trypanocides afin de réduire les risques a long terme de Ia chimiorésistance sans compromettre Ia capacité des éleveurs a pouvoir protéger leurs animaux contre les effets néfastes de la trypanosomose animale. Le projet est réalisé au Burkina Faso, au Mali et en Guinée par l’lnstitut International de Recherche sur l’Elevage (lLRl) en collaboration avec d’autres organisations. Des approaches de solutions sont alors proposees de maniere a apporter une solution durable au phenomene de la chimioresistance

Effets de la fertilisation potassique des sols ferrugineux tropicaux sur la nutrition minérale et la productivité du cotonnier (Gossypium hirsutum L.) au Burkina Faso

L'étude a été conduite pendant deux années, dans deux stations expérimentales situées à l’Ouest et à l’Est du Burkina Faso, pour évaluer l'efficacité de la fertilisation potassique sur les rendements du cotonnier et ses effets sur les caractéristiques technologiques de la fibre de coton. Les traitements étaient constitués par lafumure minérale vulgarisée sur le cotonnier (150 kg ha-1 de 14-18-18-6S-1B + 50 kg ha-1 d'urée) à laquelle cinq doses de chlorure de potassium (0; 25; 50; 75 et 100 kg ha-1 de KCl) ont été associées. Dans un dispositif expérimental en blocs de Fisher, la nutrition minérale du cotonnier, le rendement en coton graine et ses composantes ainsi que les caractéristiques technologiques de la fibre ont été les paramètres mesurés. Les doses de potassium ont significativement amélioré la nutrition potassique du cotonnier à 70 jours après levée ainsi que les rendements en coton graine. Les doses de 75 et 100 kg ha-1de KCl étaient statistiquement équivalentes à la dose de 50 kg ha-1 de KCl qui a induit, par rapport au témoin sans KCl, une amélioration du rendement de + 139 kg ha-1 et + 214 kg ha-1 de coton graine, respectivement à Kouaré et Farako-bâ. Par rapport au témoin sans KCl, les doses de potassium n'ont pas eu d'effets significatifs sur le nombre de capsules, le pourcentage de fibre, le seed index (poids de 100 graines) ainsi que les caractéristiques technologiques de la fibre. En dépit de l'utilisation de la fumure minérale vulgarisée, les bilans potassiques étaient déficitaires. Mais les apports de KCl ont permis d'atténuer ces déficits et même d'assurer des bilans excédentaires. L'apport de 50 kg ha-1 de KCl pourrait être associé à la fumure minérale vulgarisée sur le cotonnier pour son efficacité sur le rendement et l'amélioration du bilan potassique du sol.© 2016 International Formulae Group. All rights reserved.Mots clés: Sol ferrugineux, potassium, cotonnier, rendement, Burkina FasoEnglish Title:  Effects of potassium fertilization of lixisols on mineral nutrition and productivity of cotton (Gossypium hirsutum L.) in Burkina FasoEnglish AbstractTo evaluate potassium fertilization effects on the cotton yield and fiber quality characteristics, two years study was conducted on two experimental stations, located in West and East Burkina Faso. Treatments were five rates of potassium chloride (0; 25; 50; 75 and 100 kg ha-1 KCl) associated to the recommended mineral fertilizer (150 kg ha-1 of 14-18-18-6S-1B + 50 kg ha-1 urea) of cotton. The treatments were arranged in a randomized block design. The cotton plant nutrition, yields and its components and fiber characteristics were evaluated. The cotton plant K nutrition at 70 days after emergence and cotton-seed yields were significantly improved by applied rates of potassium compared to the control. KCl application rates of 75 and 100 kg ha -1 were statistically equivalent to 50 kg ha -1 which gave a surplus cotton-seed production of 139 kg ha-1 and 214 kg ha-1, respectively in Kouaré and Farako-bâ. Compared to the control without KCl, potassium didn’t have significant effects on bolls production, fiber yield and quality, and seed index. Despite the use of recommended mineral fertilization rate, the soil K balance was negative. Potassium application reduces the K deficits and ensures positive soil K balance. Use of KCl at 50 kg ha-1 with the recommended mineral fertilizer could be done to improve cotton yield and soil K balance.© 2016 International Formulae Group. All rights reserved.Keywords: Lixisols, potassium, cotton, yield, Burkina Fas