Joint contrast optimization and object segmentation in active polarimetric images

International audienceWe present a method for automatic target detection based on the iterative interplay between an active polarimetric imager with adaptive capabilities and a snake-based image segmentation algorithm. It successfully addresses the difficult situations where the target and the background differ only by their polarimetric properties. This method illustrates the benefits of integrating digital processing algorithms at the heart of the image acquisition process rather than using them only for postprocessing

Visually narrating post-colonial lives: ghosts of war and empire

This paper is about two journeys: the first through the memories of an old soldier captured by the Japanese in the Second World War; the second through the present life to which this past gave rise, in which the old soldier tends the graves of his fellow soldiers as part of his current navigation by bus and taxi of the post-colonial landscape of Hong Kong

Polymorphism of Plasmodium falciparum Na+/H+ exchanger is indicative of a low in vitro quinine susceptibility in isolates from Viet Nam

<p>Abstract</p> <p>Background</p> <p>The <it>Plasmodium falciparum </it>NA+/H+ exchanger (<it>pfnhe1</it>, gene PF13_0019) has recently been proposed to influence quinine (QN) susceptibility. However, its contribution to QN resistance seems to vary geographically depending on the genetic background of the parasites. Here, the role of this gene was investigated in <it>in vitro </it>QN susceptibility of isolates from Viet Nam.</p> <p>Method</p> <p>Ninety-eight isolates were obtained from three different regions of the Binh Phuoc and Dak Nong bordering Cambodia provinces during 2006-2008. Among these, 79 were identified as monoclonal infection and were genotyped at the microsatellite <it>pfnhe1 </it>ms4760 locus and <it>in vitro </it>QN sensitivity data were obtained for 51 isolates. Parasite growth was assessed in the field using the HRP2 immunodetection assay.</p> <p>Results</p> <p>Significant associations were found between polymorphisms at <it>pfnhe1 </it>microsatellite ms4760 and susceptibility to QN. Isolates with two or more DNNND exhibited much lower susceptibility to QN than those harbouring zero or one DNNND repeats (median IC₅₀of 682 nM <it>versus </it>median IC₅₀of 300 nM; <it>p </it>= 0.0146) while isolates with one NHNDNHNNDDD repeat presented significantly reduced QN susceptibility than those who had two (median IC₅₀of 704 nM <it>versus </it>median IC₅₀of 375 nM; p < 0.01). These QNR associated genotype features were mainly due to the over representation of profile 7 among isolates (76.5%). The majority of parasites had <it>pfcrt76T </it>and wild-type <it>pfmdr1 </it>(> 95%) thus preventing analysis of associations with these mutations. Interestingly, area with the highest median QN IC₅₀showed also the highest percentage of isolates carrying the <it>pfnhe1 </it>haplotype 7.</p> <p>Conclusions</p> <p>The haplotype 7 which is the typical Asian profile is likely well-adapted to high drug pressure in this area and may constitute a good genetic marker to evaluate the dissemination of QNR in this part of the world.</p

Quinine-Resistant Malaria in Traveler Returning from Senegal, 2007

We describe clinical and parasitologic features of in vivo and in vitro Plasmodium falciparum resistance to quinine in a nonimmune traveler who returned to France from Senegal in 2007 with severe imported malaria. Clinical quinine failure was associated with a 50% inhibitory concentration of 829 nmol/L. Increased vigilance is required during treatment follow-up

A Escuta de Jovens em Filmes de Pesquisa

Apresenta-se trajetória de um grupo de pesquisa dedicado à produção de conhecimento sobre jovens de espaços populares no contexto de produção de filmes de pesquisa. Dois filmes são descritos e interpretados com especial destaque aos dispositivos utilizados para colocar em diálogo as narrativas de si e contextos de vida e sociabilidade de jovens através de imagens e sons. A representação fílmica não se confunde com um retrato do real, mas, em vez disso, é reconstituição através da seleção, tradução e montagem do produto que se quer compartilhar com o público. As entrevistas narrativas concebidas em bases dialógicas são elementos estruturantes da produção dos filmes que buscam apresentar o ser-jovem em sua complexidade

X band model of Venus atmosphere permittivity

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94912/1/rds5697.pd

The Science of Sungrazers, Sunskirters, and Other Near-Sun Comets

This review addresses our current understanding of comets that venture close to the Sun, and are hence exposed to much more extreme conditions than comets that are typically studied from Earth. The extreme solar heating and plasma environments that these objects encounter change many aspects of their behaviour, thus yielding valuable information on both the comets themselves that complements other data we have on primitive solar system bodies, as well as on the near-solar environment which they traverse. We propose clear definitions for these comets: We use the term near-Sun comets to encompass all objects that pass sunward of the perihelion distance of planet Mercury (0.307 AU). Sunskirters are defined as objects that pass within 33 solar radii of the Sun’s centre, equal to half of Mercury’s perihelion distance, and the commonly-used phrase sungrazers to be objects that reach perihelion within 3.45 solar radii, i.e. the fluid Roche limit. Finally, comets with orbits that intersect the solar photosphere are termed sundivers. We summarize past studies of these objects, as well as the instruments and facilities used to study them, including space-based platforms that have led to a recent revolution in the quantity and quality of relevant observations. Relevant comet populations are described, including the Kreutz, Marsden, Kracht, and Meyer groups, near-Sun asteroids, and a brief discussion of their origins. The importance of light curves and the clues they provide on cometary composition are emphasized, together with what information has been gleaned about nucleus parameters, including the sizes and masses of objects and their families, and their tensile strengths. The physical processes occurring at these objects are considered in some detail, including the disruption of nuclei, sublimation, and ionisation, and we consider the mass, momentum, and energy loss of comets in the corona and those that venture to lower altitudes. The different components of comae and tails are described, including dust, neutral and ionised gases, their chemical reactions, and their contributions to the near-Sun environment. Comet-solar wind interactions are discussed, including the use of comets as probes of solar wind and coronal conditions in their vicinities. We address the relevance of work on comets near the Sun to similar objects orbiting other stars, and conclude with a discussion of future directions for the field and the planned ground- and space-based facilities that will allow us to address those science topics

Investigations of the Mars Upper Atmosphere with ExoMars Trace Gas Orbiter

The Martian mesosphere and thermosphere, the region above about 60 km, is not the primary target of the ExoMars 2016 mission but its Trace Gas Orbiter (TGO) can explore it and address many interesting issues, either in-situ during the aerobraking period or remotely during the regular mission. In the aerobraking phase TGO peeks into thermospheric densities and temperatures, in a broad range of latitudes and during a long continuous period. TGO carries two instruments designed for the detection of trace species, NOMAD and ACS, which will use the solar occultation technique. Their regular sounding at the terminator up to very high altitudes in many different molecular bands will represent the first time that an extensive and precise dataset of densities and hopefully temperatures are obtained at those altitudes and local times on Mars. But there are additional capabilities in TGO for studying the upper atmosphere of Mars, and we review them briefly. Our simulations suggest that airglow emissions from the UV to the IR might be observed outside the terminator. If eventually confirmed from orbit, they would supply new information about atmospheric dynamics and variability. However, their optimal exploitation requires a special spacecraft pointing, currently not considered in the regular operations but feasible in our opinion. We discuss the synergy between the TGO instruments, specially the wide spectral range achieved by combining them. We also encourage coordinated operations with other Mars-observing missions capable of supplying simultaneous measurements of its upper atmosphere