INP MMIC AMPLIFIERS FOR CRYOGENIC RADIOASTRONOMICAL APPLICATIONS

Abstract Radioastronomical observation development, pushes technology research to develop equipment working up to 100-150 GHz. This trend make heavier the Low noise Amplifiers (LNA) noise contribution. A significantly improvement comes from the Indium Phosphide (InP) Technology, that gives the best noise performances in this range. Moreover radioastronomy moves also towards array receivers configuration, this implies high integration and repeatability. In the frame of the FARADAY PROJECT we were involved in designing several kind of MMIC amplifiers in the 18 to 26 GHz range in order to approach the InP technology and the MMIC design methodology

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

InP MMIC amplifiers for cryogenic radioastronomical applications

Radioastronomical observation development pushes technology research to develop equipment working up to 100-150 GHz. This trend makes the noise contribution of the low noise amplifiers (LNA) more serious. A significant improvement comes from the use of indium phosphide (InP) technology, as it gives the best noise performance in this range. Moreover, as radioastronomy is moving towards the array receiver configuration, this implies high integration and repeatability. In the frame of the FARADAY Project, we have been involved in designing several kinds of MMIC amplifiers in the 18-26 GHz range in order to approach the InP technology and the MMIC design methodology

Sequential star formation in the Cepheus molecular cloud: the S155/Cepheus B interface.

. In this paper we present new radio and nearinfrared observations of a bright Hff knot located southeast of the Cepheus OB3 association, near the ionization front that divides the S155 diffuse H ii region from the Cepheus B molecular cloud. The arcsec resolution VLA radio continuum images reveal that the previously unresolved radio source # 9, coincident with the Hff knot, is composed of four distinct sources: an extended RIDGE and three smaller diameter components. From the radio continuum spectrum and the general morphology it is possible to deduce that the RIDGE represents an ionization front in the northern part of the Hff knot. The larger of the small--diameter components is a blister-type compact H ii region, still partly bounded by high density molecular gas. Another one of these components, which is very weak, is found to be variable. The third source is definitely unresolved even at 0:4 arcsec resolution and has a non--thermal spectral index. In the latter two sources, the pr..