SIOUX project: a simultaneous multiband camera for exoplanet atmospheres studies

The exoplanet revolution is well underway. The last decade has seen order-of-magnitude increases in the number of known planets beyond the Solar system. Detailed characterization of exoplanetary atmospheres provide the best means for distinguishing the makeup of their outer layers, and the only hope for understanding the interplay between initial composition chemistry, temperature-pressure atmospheric profiles, dynamics and circulation. While pioneering work on the observational side has produced the first important detections of atmospheric molecules for the class of transiting exoplanets, important limitations are still present due to the lack of sys- tematic, repeated measurements with optimized instrumentation at both visible (VIS) and near-infrared (NIR) wavelengths. It is thus of fundamental importance to explore quantitatively possible avenues for improvements. In this paper we report initial results of a feasibility study for the prototype of a versatile multi-band imaging system for very high-precision differential photometry that exploits the choice of specifically selected narrow-band filters and novel ideas for the execution of simultaneous VIS and NIR measurements. Starting from the fundamental system requirements driven by the science case at hand, we describe a set of three opto-mechanical solutions for the instrument prototype: 1) a radial distribution of the optical flux using dichroic filters for the wavelength separation and narrow-band filters or liquid crystal filters for the observations; 2) a tree distribution of the optical flux (implying 2 separate foci), with the same technique used for the beam separation and filtering; 3) an exotic solution consisting of the study of a complete optical system (i.e. a brand new telescope) that exploits the chromatic errors of a reflecting surface for directing the different wavelengths at different foci

Brucelosis canina

Canine brucellosis caused by Brucella canis is a contageous and infectious disease that affects dogs. It has been diagnosed in EEUU and several other coutries, including Russia, Japan, Nigeria, India, China and Argentina. Natural infection can occurs by vertical or horizontal route, by means of seminal or vaginal secretions and by oronasal and conjunctival mucous. The most significating sign of the disease is abortion and reproductive failure in females and orchitis and epididimitis followed by infertility in males. The diagnosis is based on isolation of the bacteria from hemoculture and serologic tests with specific antigens of Brucella canis. The treatment is expensive, extended and not 100% effective, and the infection often reccurs after it. The transmission of Brucella canis to man commonly occurs through contact with infected dogs or their secretions or through direct laboratory exposure, but is not frequent and is easily treated.La brucelosis canina causada por Brucella canis es una enfermedad infecciosa y contagiosa que afecta a los perros. Ha sido diagnosticada en EEUU y otros países, incluyendo Rusia, Japón, Nigeria, China y Argentina. La infección natural puede ocurrir por vía vertical u horizontal, a través de secreciones seminales o vaginales, y a través de mucosa oronasal y conjuntival. Los signos más significativos de la enfermedad en la hembra son el aborto y la falla reproductiva, en los machos la orquitis y la epididimitis seguidas de infertilidad. El diagnóstico se basa en el aislamiento de la bacteria a partir de he mocultivos y pruebas serológicas con antígeno específico de Brucella canis. El tratamiento es caro, prolongado, no es 100% efectivo y la infección usualmente recurre despué s del mismo. La transmisión de Brucella canis al hombre comúnmente ocurre por contacto directo con perros infectados, sus secreciones o a través de exposisción directa en laboratorio. El contagio no es frecuente, pero cuando ocurre es fácilmente tratada

Kinetochore alignment within the metaphase plate is regulated by centromere stiffness and microtubule depolymerases

During mitosis in most eukaryotic cells, chromosomes align and form a metaphase plate halfway between the spindle poles, about which they exhibit oscillatory movement. These movements are accompanied by changes in the distance between sister kinetochores, commonly referred to as breathing. We developed a live cell imaging assay combined with computational image analysis to quantify the properties and dynamics of sister kinetochores in three dimensions. We show that baseline oscillation and breathing speeds in late prometaphase and metaphase are set by microtubule depolymerases, whereas oscillation and breathing periods depend on the stiffness of the mechanical linkage between sisters. Metaphase plates become thinner as cells progress toward anaphase as a result of reduced oscillation speed at a relatively constant oscillation period. The progressive slowdown of oscillation speed and its coupling to plate thickness depend nonlinearly on the stiffness of the mechanical linkage between sisters. We propose that metaphase plate formation and thinning require tight control of the state of the mechanical linkage between sisters mediated by centromeric chromatin and cohesion

Transmit–receive parabolic reflectarray to generate two beams per feed for multispot satellite antennas in Ka-band

This contribution describes the design of a multibeam parabolic reflectarray to produce two adjacent beams per feed in orthogonal circular Polarization (CP) simultaneously at transmit (Tx) and receive (Rx) frequencies in Ka-band. The Variable Rotation Technique (VRT) has been applied to reflectarray cells based on two types of resonant elements, which makes it possible to provide orthogonal beams at Tx and Rx, as well as to implement an in-band optimization procedure to reduce the cross-polarization. A 90-cm parabolic reflectarray has been designed, manufactured and tested to produce multiple adjacent beams in RHCP and LHCP at both 20 and 30 GHz. The results are satisfactory and validate the concept of generating two spaced beams in orthogonal CP by a single feed, changing the polarization of the beam between Tx and Rx. This concept can be suitable for multispot satellites in Ka-band, enabling to halve the number of onboard antennas and feedsAgencia Estatal de Investigación | Ref. TEC2016-75103-C2-1-RAgencia Estatal de Investigación | Ref. FJCI-2016-29943European Space Agency | Ref. 4000117113/16/NL/A

Parabolic reflectarray antenna to generate multiple beams for geostationary high throughput satellites in Ka-band

This contribution describes the design and simulations of a multibeam 1.8 m parabolic reflectarray antenna for geostationary high throughput satellites (HTS) in Ka-band. The parabolic reflectarray generates two orthogonal circularly polarized beams per feed simultaneously at 19.7 and 29.5 GHz, by the variable rotation technique. The antenna is made of 62 654 reflectarray cells, which include two types of printed elements independently rotated and adjusted. The elements have been optimized one by one to ensure the required phase-shift at each frequency. A novel design approach has made it possible to promptly obtain an initial layout of every element with a very low computational cost. The simulated radiation patterns show that the parabolic reflectarray, illuminated by 27 dual-circularly polarized feeds, can generate 54 spot-beams in two orthogonal polarizations, with a beam spacing of 0.56° between adjacent beams. The design and simulation tools have been validated by a parabolic reflectarray scaled in a factor of 0.5, which has been manufactured and tested. The proposed reflectarray would allow to generate a complete multi-spot coverage from a geostationary HTS with only two parabolic reflectarrays, instead of four reflector antennas, also reducing the number of feeds by half, since every feed generates two beams.Agencia Estatal de Investigación | Ref. PID2020-113979RB-C22Agencia Estatal de Investigación | Ref. PID2020-114172RB-C21-2Agencia Estatal de Investigación | Ref. PDC2021-120959-C2

Advanced multibeam antenna configurations based on reflectarrays: providing multispot coverage with a smaller number of apertures for satellite communications in the K- and Ka-bands

This article presents some recent developments in multiplebeam antennas (MBAs) based on reflectarrays for communication satellites in the Kurz (K) and Kurz-above (Ka) bands. The existing high-throughput satellites commonly employ four reflector antennas to provide cellular coverage that is formed by multiple spot beams in a four-color scheme. Reflectarray antennas are proposed as an attractive solution for the design of novel MBA configurations to produce multispot coverage, with a smaller number of apertures than conventional MBA systems based on reflector technology. Single and dual reflectarray configurations have been considered for the purpose of exploiting their ability to produce independent beams in different polarizations and frequencies.Agencia Estatal de Investigación | Ref. TEC2016-75103-C2-1-RMinisterio de Economía y Competitividad | Ref. TEC2015-65353-RXunta de Galicia | Ref. GRC2015/018European Space Agency | Ref. 4000117113/16/NL/A