Reference stars compiled catalogue around extragalactic radio sources. Reduction techniques and the first results

Some differential reference stars catalogues around extragalactic radio sources obtained from photographic and CCD-observations at different observatories are considered. Compiled catalogue of star positions in fields of 30 ×30 is intended for reduction of ERS optical observations using the telescopes equipped with CCD-cameras. Photographic observations of the fields around 74 ERS were made at the Pulkovo Observatory, around 115 ERS – at the AO KNU, around 188 ERS – at the AIRA in Bucharest. The 208 fields around ERS at NAO using the telescope equipped with a CCD-camera were obtained. The first results of the creation of uniform compiled catalogue are given. Astrometric positions for stars brighter than 16 magnitude in more than 20 fields around ERS are presented. A comparison of our results with those of other authors is made

EURONEAR - Data Mining of Asteroids and Near Earth Asteroids

Accepted in Astronomische Nachrichten (Feb 2009). The definitive version is available at www3.interscience.wiley.com.International audienceBesides new observations, mining old photographic plates and CCD image archives represents an opportunity to recover and secure newly discovered asteroids, also to improve the orbits of Near Earth Asteroids (NEAs), Potentially Hazardous Asteroids (PHAs) and Virtual Impactors (VIs). These are the main research aims of the EURONEAR network. As stated by the IAU, the vast collection of image archives stored worldwide is still insufficiently explored, and could be mined for known NEAs and other asteroids appearing occasionally in their fields. This data mining could be eased using a server to search and classify findings based on the asteroid class and the discovery date as "precoveries" or "recoveries". We built PRECOVERY, a public facility which uses the Virtual Observatory SkyBoT webservice of IMCCE to search for all known Solar System objects in a given observation. To datamine an entire archive, PRECOVERY requires the observing log in a standard format and outputs a database listing the sorted encounters of NEAs, PHAs, numbered and un-numbered asteroids classified as precoveries or recoveries based on the daily updated IAUMPC database. As a first application, we considered an archive including about 13,000 photographic plates exposed between 1930 and 2005 at the Astronomical Observatory in Bucharest, Romania. PRECOVERY can be applied to other archives, being intended as a public facility offered to the community by the EURONEAR project. This is the first of a series of papers aimed to improve orbits of PHAs and NEAs using precovered data derived from archives of images to be data mined in collaboration with students and amateurs. In the next paper we will search the CFHT Legacy Survey, while data mining of other archives is planned for the near future

Exploration of the Solar System : projection of the past into the future

International audienc

Exploration of the Solar System : projection of the past into the future

International audienc

Exploration of the Solar System : projection of the past into the future

International audienc

Review of Flowering Control in Industrial Hemp

Hemp ( Cannabis sativa L.) is a dioecious annual that commences its reproductive cycle when photoperiods are shorter than a critical length. Photoperiod-sensitive varieties grown in low latitudes with short-day lengths tend to produce early flowering, short plants affecting the yield and quality of the fiber. The photoperiodic sensitivity of the crop could be controlled by the activation or deactivation of genes triggered by the change in light duration perceived by photoreceptive pigments. The sexual dimorphism of Cannabisis genetically determined by the XY chromosomal mechanismal though sexual morphology is primarily a result of endogenous plant growth regulator levels that fluctuate in response to environmental variables. Occurrence of occasional hermaphroditic flowers and monoecious plants are probably the result of these fluctuations. Understanding the mechanisms of photoperiodicity and sexual inheritance contributes to advances in breeding and crop management that may underpin the expansion of the commercial cultivation of the crop in nontraditional agroecological domains

Identification of QTLs for sex expression in dioecious and monoecious hemp (Cannabis sativa L.)

Hemp (Cannabis sativa L.) is a diploid species including both dioecious and monoecious cultivars with hetero- and homomorphic sex chromosomes, respectively. It displays a high plasticity of sex expression, i.e., the ratio of female and male flowers. In this study, we investigated the role of sex chromosomes in the genetic determinism of sex expression in dioecious and monoecious hemp. The experimental materials were three F1 segregating populations, two dioecious (C1 and C2: ‘Carmagnola’ ♀ × ‘Carmagnola’ ♂), and one monoecious (UF: ‘Uso 31’ × ‘Fedora 17’). A ‘sex’ phenotypic marker was mapped in C1 and C2. In total, 23, 42, and 26 AFLP markers (71 markers in total) were mapped to three, nine, and three co-segregation groups putatively located on sex chromosomes in C1, C2, and UF, respectively. Recombination rates with sex ranged from 0 to 0.5. Five sex-linked markers were detected in UF, revealing homologies between the X chromosomes of monoecious hemp and the X and Y chromosomes of dioecious hemp. Five QTLs associated with quantitative variations in sex expression were identified in each map. Four markers associated with variations in sex expression in UF segregated with sex or accounted for a putative QTL in C1 or C2. Two QTLs and three of these markers were mapped in UF in a region homologous to the sex-locus region of the dioecious maps. Given these results, conducting further research on the genetic determinism of sex expression in hemp using a quantitative approach appears relevant