NASA/SAO Astrophysics Data System 2018-03-05T18:41:06+00:00 https://ui.adsabs.harvard.edu/ ADS Team adshelp@cfa.harvard.edu Copyright © 2015, NASA/SAO Astrophysics Data System http://adsabs.github.io/blog/asclepias Asclepias - Enabling software citation & discovery workflows 2018-02-05T00:00:00+00:00 2018-02-05T00:00:00+00:00 Edwin Henneken <p>Soon, if not already, the research lifecycle will be fully digital. Every stage can be captured by one or more digital objects, each of which carries specific knowledge with regards to that stage. The most obvious inhabitant of this digital cosmos is the scholarly publication, but there are many more species, ranging from observation proposals, datasets, software to posters and presentations. With repositories like mission data archives, <a href="https://figshare.com/">Figshare</a> and <a href="https://zenodo.org/">Zenodo</a>, all of these objects can, in principle, be made discoverable and citable. In this blog we focus on one particular digital object: software. Enter <strong><em>Asclepias</em></strong>! Asclepias, “<em>Enabling software citation and discovery workflows</em>”, is a project funded through a grant from the Alfred P. Sloan Foundation to the American Astronomical Society (AAS), and it involves collaboration between the AAS, Zenodo, the ADS and Thomas Robitaille as freelancer. Why this collaboration? It reflects the fact that no one stakeholder can “solve” the problem of software citation.</p> <div class="text-center"> <img class="img-thumbnail" src="/blog/images/blog_2018_02_05_lifecycle.jpg" /> Figure source: "Research Life Cycle" image from UC Irvine [Library Digital Scholarship Services](https://www.lib.uci.edu/dss) </div> <table> <thead> <tr> <th style="text-align: left"> </th> <th style="text-align: left"> </th> </tr> </thead> <tbody> <tr> <td style="text-align: left"><img src="/blog/images/blog_2018_02_05_AAS_logo.png" alt="AAS" class="img-responsive" /></td> <td style="text-align: left">Gus Muench</td> </tr> <tr> <td style="text-align: left"><img src="/blog/images/blog_2018_02_05_ADS_logo.png" alt="ADS" class="img-responsive" /></td> <td style="text-align: left">Alberto Accomazzi, Sergi Blanco-Cuaresma, Edwin Henneken</td> </tr> <tr> <td style="text-align: left"><img src="/blog/images/blog_2018_02_05_Zenodo_logo.png" alt="Zenodo" class="img-responsive" /></td> <td style="text-align: left">Lars Holm Nielsen, Krzysztof Nowak , Alexander Ioannidis</td> </tr> <tr> <td style="text-align: left"><img src="/blog/images/blog_2018_02_05_TR_logo.png" alt="Robitaille" class="img-responsive" /></td> <td style="text-align: left">Thomas Robitaille</td> </tr> </tbody> </table> <p>What is so special about software citation that it takes so many parties to deal with it properly? This becomes clear when you think about how to move from a position where the curation and preservation of software products has been taken care of, to one where these products are discoverable, together with their links to the scholarly literature (by means of citations or otherwise). One challenge is that currently, there is no established standard or policy for citing software in scholarly publications. Writing a “software paper” may seem like a work-around, but it is not a very good one. It can work if you just write one, static piece of software. You describe how it works, acknowledge contributors and, perhaps, where people can get a copy, and you’re done. In all other cases, even though it is better than nothing, a “software paper” is just a bad proxy for representing all aspects. Software is a highly dynamical object, especially when it evolves from version to version, with different contributors and different characteristics. For this reason, it is important to capture the acknowledgement of actual software products. Since reworking the entire, established process of capturing scholarly acknowledgement (read: “citations”) is extremely hard, to say the least, adapting the existing mechanism of finding citations to include software, will be the next best thing.</p> <p>This is exactly what the Asclepias project focuses on. Its goal is to <strong>promote scientific software</strong> into an identifiable, citable, and preservable object. The project focuses on the needs of two of the most important roles researchers play in the scholarly ecosystem: <strong>authors</strong> of scholarly manuscripts and <strong>developers</strong> of scientific software. This goal can only be reached if the research community participates, and the research community can only be expected to participate if there are tools and workflows in place that make the citation of software products just as easy as citing a publication. What needs to be in place to make this happen? The publisher (AAS) will need to implement practices and tools that will support the integration of software citations into the scholarly publishing workflow. From the viewpoint of bibliographic indexing services (ADS), the implementation means the development of first-class support of a software framework to detect software citations and take all necessary steps to attribute and expose these citations. For repositories (Zenodo), implementation means interoperability with Github and similar codebases (like Bitbucket). The minting of DOIs is one step in this integration, and being able to send out notifications that (astronomy related) software has been released, including version updates, is another. All these steps are only possible if <strong>metadata standards</strong> for software packages are adopted. Just slapping a DOI on a digital object is not a structural solution, not by a long shot. It may help an object location be persistent, but that is not how you discover something. That is where the metadata is essential! Within the Asclepias project, the development of metadata is guided by the software citation practices put forward by the FORCE11 Software Citation Implementation Group. When all of this is in place, the three stakeholders will have put in place the framework that will provide the research community with simple instructions for how to make software discoverable and how to include software citations in the process of writing a scholarly paper.</p> <p>What does all of this mean in practice? Let’s look at an example. The Python module <em>corner.py</em> (previously known as <em>triangle.py</em>) is widely used in astronomy. Its main developer, Daniel Foreman-Mackey, made it available on <a href="https://github.com/dfm/corner.py">Github</a> and published an <a href="http://joss.theoj.org/papers/10.21105/joss.00024">entry</a> in the Journal of Open Source Software (JOSS). The ADS has a <a href="http://ui.adsabs.harvard.edu/#abs/2016JOSS.2016...24F/abstract">record</a> for this JOSS software paper, and as a result citations are being captured (provided people cite this record properly). As of November 9, 2017, this JOSS paper accumulated 77 citations.</p> <div class="text-center"> <img class="img-thumbnail" src="/blog/images/blog_2018_02_05_JOSS_corner.png" /> </div> <p>Thanks to Zenodo’s interoperability with Github, records were created for both <em>triangle.py</em> and <em><a href="https://doi.org/10.5281/zenodo.53155">corner.py</a></em>. Zenodo mints a DOI for each software version and also a so-called concept DOI. The concept DOI is available for when you don’t want to cite a specific software version, but just “the latest”. The crucial step that make this interoperability possible is the authentication within Zenodo, using your Github account, allowing Zenodo to view and retrieve your repositories on Github. For details, see: https://guides.github.com/activities/citable-code/.</p> <div class="text-center"> <img class="img-thumbnail" src="/blog/images/blog_2018_02_05_zenodo.png" /> </div> <p>The next step is to go through the reference data in the ADS holdings and see if we find any evidence of the Zenodo DOIs, corresponding with the different versions of both <em>triangle.py</em> and <em>corner.py</em>. The table below shows the results (as of Feburary 5, 2018).</p> <table> <thead> <tr> <th> </th> <th style="text-align: center"> </th> <th style="text-align: right"> </th> </tr> </thead> <tbody> <tr> <td>10.5281/zenodo.10598</td> <td style="text-align: center">triangle</td> <td style="text-align: right">2</td> </tr> <tr> <td>10.5281/zenodo.11020</td> <td style="text-align: center">triangle</td> <td style="text-align: right">40</td> </tr> <tr> <td>10.5281/zenodo.45906</td> <td style="text-align: center">corner</td> <td style="text-align: right">16</td> </tr> <tr> <td>10.5281/zenodo.53155</td> <td style="text-align: center">corner</td> <td style="text-align: right">7</td> </tr> </tbody> </table> <p>This analysis shows that authors are already citing the different versions of both modules, but also that it results in a significant amount of additional citations!</p> <p>The bottom line is that all of this is great in many ways. From the researcher’s perspective, it provides proper attribution for their role (and impact) as software developer and it provides them with a means to monitor on how their software is being used, specifically with regards to versions. The fact that, in this process, software gets deposited in a repository and proper metadata is attached and registered, is great for the community and science in general. It supports the goals of preservation and reproducibility. In this way, these efforts greatly improve the accurate recording of crucial aspects of the research lifecycle. Of course, none of this goes anywhere if the research community does not participate. There was a special session on software citation during the 231st AAS Meeting in National Harbor (session 307 Astronomy Software Publishing: Community Roles and Services, in National Harbor 2, 10:00 am – 11:30 am). If you are interested to hear more about this project, or software citation in general, please write us (<a href="ads@cfa.harvard.edu">ads@cfa.harvard.edu</a>). More details on the Asclepias project can be found here:</p> <ul> <li>Muench, August; Accomazzi, Alberto; Holm Nielsen, Lars (2017), “Asclepias: Enabling software citation &amp; discovery workflows”, poster presented at LISA VIII conference (https://doi.org/10.5281/zenodo.803474)</li> <li>Henneken, Edwin, Accomazzi, Alberto, Blanco-Cuaresma, Sergi, Muench, August, &amp; Nielsen, Lars Holm. (2017). “Asclepias - Capturing Software Citations in Astronomy”, talk given at the Metrics workshop during the 2017 ASIS&amp;T Annual Meeting (http://doi.org/10.5281/zenodo.1011088)</li> </ul> http://adsabs.github.io/blog/roadmap ADS Bumblebee: What to Look Forward to in 2018 2018-01-02T00:00:00+00:00 2018-01-02T00:00:00+00:00 Kelly Lockhart <p><a href="https://ui.adsabs.harvard.edu/">ADS Beta</a>, codenamed Bumblebee, is nearing parity with <a href="http://adsabs.harvard.edu/">ADS Classic</a>! The ADS development team has been working on Bumblebee since 2015, an outgrowth of earlier efforts (ADS Labs, ADS 2.0) to modernize the look and capabilities of ADS. While Classic has been a mainstay of astronomical research for the past 25 years, receiving 50,000 visitors a day and over three-quarters of a million visitors every month, the legacy code it’s built on prevents significant improvements in features, speed, or capacity.</p> <p>In addition to bringing the ADS architecture up-to-date, Bumblebee provides a much richer search experience. For the first time, users can search the contents of many papers, such as the article full text, acknowledgements, and author affiliations. They can also preview parts of the paper, such as embedded graphics and text snippets showing the search term in context, from the search results and article pages. These improvements provide much more functionality in searching than Classic’s metadata-only search capabilities, which are limited to author, title, and abstract queries. Besides indexing many more fields than Classic, Bumblebee also offers other more advanced features, such as improved paper metrics and paper and author network visualizations.</p> <p><img src="/img/graphics.png" alt="author network" class="img-responsive" /> <i>Graphics from an example individual article. Clicking on an individual figure thumbnail links to an expanded view in the AAS Astronomy Image Explorer, which includes caption text. Graphics are available for articles from all AAS journals, A&amp;A, and several Elsevier publications. Graphics extraction is also attempted for arXiv publications. </i> <br /></p> <p><img src="/img/paper-network.png" alt="paper network" class="img-responsive" /> <i>Paper network for John Huchra.</i> <br /></p> <p>While Bumblebee’s functionality has advanced beyond that of Classic in many ways, it is technically still in beta and is missing some Classic functionality. We plan on closing this gap over the next few months, but in the meantime, here’s a list of upcoming features to look forward to in Bumblebee over the coming months before we officially remove the beta label:</p> <ul> <li>Custom bibliography export formats</li> <li>NED object searches and filtering (similar functionality for SIMBAD objects is already available)</li> <li>Availability of arXiv records within a few hours of the daily arXiv posting (currently there is a day of lag in Bumblebee vs. Classic for these records)</li> <li>Reporting on collaborators/affiliations for use with NSF grant applications</li> <li>Additional data and paper linking options</li> </ul> <p>Under the current development schedule, Bumblebee will reach parity with Classic and lose its beta label early in the second quarter of 2018. At that point, we’ll begin more advanced testing with end users to discover any remaining issues and resolve those as quickly as possible. Over the following year, as Bumblebee matures, we’ll mark Classic for retirement and eventually redirect all Classic search URLs to Bumblebee. Within a year of Bumblebee reaching maturity, we plan on discontinuing web access to Classic. The Classic API will also eventually be retired in favor of the Bumblebee API, though that will happen on a slightly longer timeline than for the front-end web interface.</p> <p>Realizing that change doesn’t always come easy, we are working on mitigation plans to smooth the transition. Users worried about losing the Classic search interface may appreciate <a href="https://ui.adsabs.harvard.edu/#classic-form">Bumblebee’s Classic search form</a>. Bookmarked Classic links to any individual abstract pages or hardcoded search queries, such as an author search, will continue to work. And we’ve got a few tricks up our sleeves to help users acclimatize to Bumblebee’s search syntax, which we’ll be rolling out once Bumblebee’s beta phase has ended.</p> <p>Switching off a 25-year-old legacy system is no easy task! If you’d like to get involved and volunteer as an end user tester, <a href="mailto:adshelp@cfa.harvard.edu">email us</a> or come chat with us at our AAS 231 booth, #630. And as always, if you’d like to share any feedback on the new system, <a href="mailto:adshelp@cfa.harvard.edu">drop us a line</a>.</p> http://adsabs.github.io/blog/adsug ADS Welcomes Its Users Group for Their Second Annual Meeting 2017-12-12T00:00:00+00:00 2017-12-12T00:00:00+00:00 Kelly Lockhart <p>The ADS team was pleased to welcome our <a href="http://adsabs.harvard.edu/adsug.html">Users Group</a> (ADSUG) to our home base here at the <a href="https://www.cfa.harvard.edu/">CfA</a> for their <a href="http://ads.harvard.edu/adsug/2017b/ADSUsersGroupProgram.html">second visit</a> on 2-3 November. The ADSUG meets roughly once per year to hear about the status of ongoing and upcoming projects and to advise the ADS team on our operations and potential system enhancements. The group is comprised of members from the greater astronomy community, including scientists and librarians. Several of our members are also involved in digital archives or other computing-intensive projects. Their advice and insights are quite valuable in determining the direction of ADS development.</p> <p>One of the ADSUG members is Erick Peirson, lead system architect at arXiv. Erick spent an extra day with us before the official ADSUG meeting to discuss our ongoing projects. ADS and arXiv have a long history of collaboration, including a special daily ingest into ADS of arXiv papers, ADS’s use of arXiv read statistics, and arXiv’s use of the ADS linkage of the arXiv and published versions of a given paper. Similarly to ADS, arXiv is also in the process of upgrading their infrastructure to meet their 21st century needs; the two teams have independently selected <a href="https://blogs.cornell.edu/arxiv/2017/11/16/visit-to-astrophysics-data-system/">similar technology stacks and architectures</a>, which opens the door to closer future collaboration.</p> <p>Presentations and discussions at the main ADSUG meeting covered a lot of ground quickly over the two-day meeting. A full report is expected from the committee in the next month or so, but in the meantime, an overview of the major topics covered is given below, or check out the <a href="http://ads.harvard.edu/adsug/2017b/ADSUsersGroupProgram.html">online program</a>.</p> <h3 id="removing-the-beta-from-ads-beta-aka-bumblebee">Removing the Beta from ADS Beta (a.k.a. Bumblebee)</h3> <p>The ADS development team has been hard at work on <a href="https://ui.adsabs.harvard.edu/">ADS Beta</a>, codenamed Bumblebee, since 2015, an outgrowth of earlier efforts (ADS Labs, ADS 2.0) to modernize the interface, infrastructure, and search capabilities of ADS Classic. These development efforts are paying off and Bumblebee is now rapidly approaching feature and content parity with ADS Classic, a nearly 25-year-old system. In addition, Bumblebee provides a much richer search experience, including full-text searching for most recent publications, on-the-fly search filtering, and integration with systems such as ORCID. Full parity with Classic is expected to be reached in early 2018, and ADS Classic will be slowly phased out over the 6-12 months following that milestone.</p> <h3 id="system-architecture-improvements">System architecture improvements</h3> <p>System architecture development in Bumblebee is multi-pronged. The development team reported on recent architecture development in several areas. First, Bumblebee is cloud-based, unlike ADS Classic, which is hosted in locally maintained servers and mirror servers. Scaling up the system to ensure a snappy response time thus requires different solutions, including testing <a href="https://kubernetes.io/">Kubernetes</a> as a scalable deployment technology and other speed improvements. Second, ingesting data into the ADS databases relies on a series of pipelines to transform raw data from publishers and other sources into appropriately formatted and fielded metadata, to calculate citation data and other metrics, and to append other related information to a publication record. These pipelines are in the process of being re-engineered to improve speed and reliability. Third, the front-end interface of Bumblebee has been improved in a number of ways under-the-hood, including improved error handling. Finally, the dev team outlined future areas for improvements to the system architecture, all targeted at improving speed and reliability for users.</p> <h3 id="planetary-sciences">Planetary sciences</h3> <p>After the <a href="http://ads.harvard.edu/adsug/2017/ADSUsersGroupProgram.html">previous ADSUG meeting</a>, the <a href="http://ads.harvard.edu/adsug/2017/ADSUG_Report.pdf">committee recommended</a> that ADS investigate the effort involved in more thoroughly covering the planetary sciences literature. While much of the planetary sciences corpus is currently included in ADS, it’s technically out of the scope of ADS’s holdings and little effort has been expended to ensure its completeness. ADS reported on a preliminary study to explore what would be required to move the planetary sciences literature into our core holdings. While the study indicated that the move would be welcomed by the planetary sciences community, many of whom have astronomy backgrounds and are already familiar with ADS, it would require a good deal of effort on the part of ADS. The ADSUG is expected to make a recommendation on how ADS should follow up on this preliminary study.</p> <h3 id="software-citations-project-asclepias">Software citations (Project Asclepias)</h3> <p>ADS, in collaboration with AAS and <a href="https://zenodo.org">Zenodo</a>, is working to improve citations to software products. Project <a href="https://github.com/asclepias/">Asclepias</a> allows developers of astronomy-related software to upload their versioned code to an online repository such as Github, publish a released version in Zenodo, and receive a DOI for their code. The Zenodo DOI enables researchers to cite the appropriate version of the code directly, without resorting to hacks such as citing a published article describing the software. ADS will soon track the citations to these Zenodo DOIs, allowing researchers with a focus on software development to properly receive credit for their work. Asclepias will be reported on more thoroughly in an upcoming blog post.</p> <h3 id="affiliations-and-collaborations">Affiliations and collaborations</h3> <p>Author affiliations have long been included in ADS but successfully searching for an author by including their affiliation as a search term is non-trivial. This is in large part due to lack of consistency in how affiliations are recorded. To take ADS’s home institution as an example, an author could record their affiliation as “Center for Astrophysics,” “Harvard-Smithsonian Center for Astrophysics,” “CfA,” or one of many other variants. Mapping these variants to each other is a complex problem that we are solving by incorporating machine learning techniques. The implementation of this new feature is still underway, but will eventually allow users to more confidently search using author affiliations as a search term.</p> <p>A related issue is that of large collaborations, such as LIGO. For arXiv e-prints and conference proceedings, few authors explicitly list all members of large collaborations, instead generally listing the name of the collaboration itself and perhaps a small number of authors. (Published journal articles do generally include the full author lists.) Searching for a member of a given collaboration will thus fail to find any publications that are “authored” by the collaboration. In addition, similarly to author affiliation, there are many published variants of a given collaboration’s name (e.g. LIGO Scientific Collaboration vs. LIGO Collaboration). With the rise of more and larger collaborations and their prominence, ADS is exploring how best to resolve this issue.</p> <h3 id="orcid">ORCID</h3> <p>ORCID is a non-profit organization that issues ORCID IDs, a method of disambiguating authors, especially those with common names. <a href="../blog/orcid-claims">ADS has incorporated ORCID functionality into Bumblebee</a>, allowing authors to claim their papers. Papers with approved claims are then discoverable when searching by an author’s ORCID ID, allowing authors to maintain a personal bibliography. ADS is exploring methods for improving and expanding ORCID functionality within the system.</p> <h3 id="future-directions">Future directions</h3> <p>We wrapped up the ADSUG meeting by discussing future directions with the committee, including some long-term possibilities for ADS.</p> <p>Based on our presentations and their own discussions, the ADSUG is currently preparing a report with their suggestions for current and future development; that report will be available on the <a href="http://adsabs.harvard.edu/adsug.html">ADSUG page</a> when ready. We also welcome community input—if you’re interested in contributing to or serving on the ADSUG, contact the ADSUG chair or your nearest member!</p> http://adsabs.github.io/blog/100M-citations ADS Indexes Its 100,000,000th Citation 2017-10-05T00:00:00+00:00 2017-10-05T00:00:00+00:00 Kelly Lockhart <h2 id="108-citations-and-counting">10<sup>8</sup> Citations and Counting!</h2> <p>The ADS has reached its 100,000,000th citation! We hit this milestone the last week of September during our daily paper ingest. The 10<sup>8</sup> citation occurred during a batch ingest of papers that generated over a million citations. The most highly cited paper that received a citation in this ingest (and thus the unofficial winner of the 10<sup>8</sup> citation prize) is <a href="https://ui.adsabs.harvard.edu/#abs/2016A&amp;A...594A..13P/abstract" target="_blank">“Planck 2015 results. XIII. Cosmological parameters.”</a> The citing paper is <a href="https://ui.adsabs.harvard.edu/#abs/2017MNRAS.471.4606A/abstract" target="_blank">“Constraining the mass of light bosonic dark matter using SDSS Lyman-α forests.”</a></p> <p>Our citations database has doubled in roughly the last 6 years. The growth in citations is rapid: the number of citations in the database increased <a href="https://ui.adsabs.harvard.edu/#abs/2007ASPC..377...69A/abstract" target="_blank">nearly five-fold in the last decade</a> and by <a href="https://ui.adsabs.harvard.edu/#abs/1999AAS...195.8209D/abstract" target="_blank">two orders of magnitude in the last two decades</a>.</p> <p><img src="/blog/images/blog_2017-10-05_image01.png" width="600" /></p> <p>The number of records in the database that have been cited at least once has also increased over the same timespan, though not as quickly as the number of citations. The number of records in physics and astronomy that have been cited at least once has nearly doubled in the last 8 years. The more rapid increase in the number of citations than in the number of papers being cited is more easily visualized by the figure below, and is best understood when thinking of the citation dataset as a network of papers connected by citations. The figure, originally published as figure 4 in <a href="https://ui.adsabs.harvard.edu/#abs/2012opsa.book..253H/abstract" target="_blank">“The ADS in the Information Age - Impact on Discovery”</a> and using data from 1980–2006, shows the number of edges (or number of citations) as a function of the number of nodes (or records that have been cited). The nonlinear growth of the number of citations is evidence of network densification.</p> <p><img src="/blog/images/blog_2017-10-05_image02.png" width="600" title="Citations (edges) vs. records (nodes), for the period from 1980 to 2006" /></p> <p>This is partly a consequence of the growth in the average number of references in a bibliography, seen in the figure below (originally figure 5 from the <a href="https://ui.adsabs.harvard.edu/#abs/2012opsa.book..253H/abstract" target="_blank">same publication</a>). This trend has only increased since widespread adoption of electronic publishing in the late 1990s, seen as the upwards deviation from the linear trend in bibliography growth.</p> <p><img src="/blog/images/blog_2017-10-05_image03.png" width="600" /></p> <p>The process by which a paper is cited in the ADS is not always obvious to our users. When a paper is ingested, the publisher-provided reference list is read. (For arXiv e-prints or other works without separate reference lists, the paper’s full text is scanned and references are extracted directly from the text.) Individual reference strings are recognized and the bibliographic tokens within them are parsed. We then attempt to match the parsed reference metadata against the existing records within ADS. When a possible match is found, we compute a similarity score between the parsed reference data and that of the potential match in ADS. If the similarity score is high enough, the reference is accepted and a reference/citation pair is created between the referencing paper and the cited paper. The citations table is formed by inverting the references table. The resulting citations table is then checked for duplicates, such as from previous versions of the citing paper that have appeared on the arXiv.</p> <p>Papers will be properly cited in ADS if and only if the following conditions are met: the citing paper is in ADS, ADS has access to the full text (or at least the references section) of the citing paper, the reference to the cited paper is properly parsed and identified (which requires that the references are in a recognizable format), and the cited paper is in ADS. It is this process that has produced over 100 million citations to date! With all the steps involved, it is possible that our system will miss a citation here and there, despite our best efforts at curating the database. We rely on our users’ feedback to continuously improve our citation coverage and welcome your input, so if you see something wrong, please <a href="http://adsabs.harvard.edu/user_feedback.html" target="_blank">let us know</a>!</p> http://adsabs.github.io/blog/scheduled-downtime ADS Classic Downtime 2017-04-12T00:00:00+00:00 2017-04-12T00:00:00+00:00 ADS Team <h2 id="ads-unavalable-on-april-13-2017">ADS Unavalable on April 13, 2017</h2> <p>The main ADS site at the Harvard-Smithsonian Center for Astrophysics (CfA), <a href="http://adsabs.harvard.edu">http://adsabs.harvard.edu</a>, will be shutdown on April 13 at 4pm EDT and will remain unavailable till approximately 11pm due to scheduled maintenance of the local power supply line.</p> <p>During this time, you can still access the ADS Classic interface on one of our mirror sites: <a href="http://cdsads.u-strasbg.fr/mirrors.html">http://cdsads.u-strasbg.fr/mirrors.html</a>. The myADS notification service will be unavailable for the duration of the downtime.</p> <p>The ADS Bumblebee interface will remain available, although some of its link-out and export functionality will be limited. Please feel free to use one of the available Bumblebee search forms:</p> <ul> <li><a href="https://ui.adsabs.harvard.edu/">Bublebee modern search form</a></li> <li><a href="https://ui.adsabs.harvard.edu/#classic-form">Bumblebee classic search form</a></li> </ul> <p>The downtime will also affect the SIMBAD and VizieR mirrors at the CfA: <a href="http://simbad.harvard.edu/">http://simbad.harvard.edu/</a> and <a href="http://vizier.cfa.harvard.edu/">http://vizier.cfa.harvard.edu/</a>.</p> <p>For the latest updates, please see our twitter feed: <a href="https://twitter.com/adsabs">https://twitter.com/adsabs</a>.</p>
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