Genomic imprinting and assisted reproduction

Imprinted genes exhibit a parent-of-origin specific pattern of expression. Such genes have been shown to be targets of molecular defects in particular genetic syndromes such as Beckwith-Wiedemann and Angelman syndromes. Recent reports have raised concern about the possibility that assisted reproduction techniques, such as in vitro fertilization or intracytoplasmic sperm injection, might cause genomic imprinting disorders. The number of reported cases of those disorders is still too small to draw firm conclusions and the safety of these widely used assisted reproduction techniques needs to be further evaluated

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Évaluation de l’exactitude d’un MNS extrait d’une image IKONOS sur une zone urbaine et sa banlieue

The availability of IKONOS stereo pairs has made it possible to generate Digital Surface Models of IKONOS data. Though it is possible to obtain a DSM from two images with a different viewing angle on the same area, it is preferred to work with products ordered as stereo. Such stereo pairs have images that are made in the same orbital pass, resulting in a much better geometry of the stereo model. In this paper the accuracy of an IKONOS derived DSM of urban areas is assessed, based on DSMs from aerial photography and laser scanning. The quality and accuracy of a DSM derived from IKONOS stereo pairs has been assessed for test zones in two cities, Ghent and Liege. The test zones are characterized by a typical urban morphology (city center, residential, industry). The accuracy has been assessed for each of the different types of urban morphology in the study areas. An error surface is obtained by calculating the difference between the generated IKONOS surface models and reference surface models. This surface is used as a measure for the accuracy of the IKONOS surface model. Reference surface models from different origins are used (aerial photography, lidar, large scale 3D database). For the test zones in Liege, the relation between the DSM accuracy and different land cover types is studied in detail. Also the relation between DSM error and the topography will be investigated.SPIDE

Generation of digital surface models and orthophotos of urban areas with IKONOS stereopairs

The purpose of the presented research project is to investigate how present-day EO-technology can support local and regional decision-making, particularly in Belgium, and to develop prototype versions of value-added products that fulfill some of the actual information needs, as expressed by Belgian authorities at the local and at the regional level. One of the technical research modules is focussing on the geometrical aspects of VHR data processing. Due to the capability of the IKONOS sensor up to an angle of 26° off-nadir, the satellite can take stereo image pairs. An IKONOS stereo pair consists of two images of the same location taken from two different perspectives on the same orbital pass. Although it is possible to obtain a stereopair from two images from different orbital passes and with a large time interval, it is proved that the stereopairs ordered from Spaceimaging or resellers gives better results (2004, Taillieu et al.). This paper describes the method applied for DSM generation from an IKONOS stereopair, over an urban area. The geometrical accuracy of the DSM is compared with the accuracy of a DSM, derived from aerial photography at scales of 1:12000 and 1:4000. The satellite-derived DSM is used for ortho-rectification of VHR imagery. The accuracy of the ortho-rectified images is compared with ortho-rectifications of the same images, based on the aerial photo DSM.SPIDE