Management Team

Chair Fredrick Jenet University of Texas, Brownsville
Former Chair Maura McLaughlin West Virginia University
Member Zaven Arzoumanian Universities Space Research Association & Nasa Goddard Space Flight Center
Member Jim Cordes Cornell University
Member Victoria Kaspi McGill University
Member Xavi Siemens University of Wisconsin, Milwaukee

Working Group Leads

Astrophysics / Sources Sarah Burke-Spolaor NASA Jet Propulsion Laboratory
Cyber-InfrastructureRobert Ferdman McGill University
Education and Outreach Ryan LynchMcGill University
Gravitational Wave Detection Xavier Siemens University of Wisconsin-Milwaukee
Instrumentation Scott RansomNRAO
International Engagement Andrea LommenFranklin & Marshall College
Interstellar Medium Mitigation Dan StinebringOberlin College
Noise Budget Jim Cordes Cornell University
Searching Duncan Lorimer West Virginia University
Strategic Planning Jim Cordes Cornell University
Timing David Nice Lafayette College

By Laws

1. Purpose


The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) is a collaboration of researchers who are actively engaged in using North American radio telescopes to detect and study gravitational waves via pulsar timing.

In order to further this purpose, the members of NANOGrav work to obtain observing time on relevant telescopes, advance instrumentation and algorithms, obtain funding, publish relevant research results, and engage their professional colleagues, potential sponsors, and the public regarding the detection and study of gravitational waves via pulsar timing. NANOGrav is one of the founding members of the International Pulsar Timing Array (IPTA) and collaborates with its international partners in advancing the goal of the detection and study of gravitational waves. The foregoing activities illustrate the range, but shall not be taken to preclude other activities that would advance the purposes of NANOGrav.

NANOGrav encourages diversity among its members and leadership. Diversity refers to the variety of personal experiences, values, and worldviews that arise from differences of culture and circumstance. Such differences include, but are not limited to, race, ethnicity, gender, age, religion, language, abilities/disabilities, sexual orientation, gender identity, socioeconomic status, and geographic region.

2. Membership


Membership of NANOGrav is open to any researcher or institution that can make a meaningful contribution to furthering the goals of NANOGrav. The NANOGrav Membership Policy describes levels of Membership and the process by which researchers and institutions can join and sustain their Membership in NANOGrav.

3. Officers


Officers of NANOGrav shall consist of a Chair, a Management Team, and representatives to the IPTA Steering Committee.

The Collaboration shall elect a Chair to represent its interests to the larger community and to act in an executive capacity for the Collaboration.

All Senior Personnel are eligible to stand for election to the position of Chair. The Chair serves for a term of two years.1 A person may serve no more than two consecutive terms in the position of Chair, but may be re-elected as Chair at a later time. The Chair may designate a member of the Management Team to act in his/her absence for a limited duration.

If the Chair resigns or is no longer a member, the Management Team shall select one of its members to serve in the position of Chair until the election can be held. The election to select a person to serve the remaining term of the Chair shall be conducted as soon as reasonably possible. After completing the remaining term, the individual thus elected shall be eligible to stand for only a single consecutive subsequent term as Chair.

The Management Team for the Collaboration shall be composed of the Chair of NANOGrav, four elected Senior Personnel, and the Principal Investigators (PIs) of any large grants that are directly related to NANOGrav's mission and that involve a significant number of NANOGrav members or institutions (see examples below). The collaboration, by vote (election process described below), shall determine if a proposed project is significant enough to warrant membership. The PI’s presence on the MT, through this process, is contingent on the proposal being awarded. The Chair of NANOGrav is also the Chair of the Management Team. The Management Team has the power to plan future activities, conduct an annual review of NANOGrav Membership, arbitrate disputes, and conduct other functions that are necessary in order to ensure that the Collaboration is able to further its purpose. If the Chair is required to act in an executive capacity, the Chair shall take reasonable steps to ensure that the advice of the other Management Team members is obtained. The Chair shall report all actions undertaken and any decisions taken, either individually or by the Management Team, on a regular basis to the Collaboration.

Elected Management Team terms are two-year positions. PIs of large grants will remain MT members through the duration of the relevant grant. Members are encouraged to consider diversity in their nominations to the MT (and to leadership positions in general) in terms of gender, age, ethnicity, geography, and type of institution of which the nominee is a part.

The previous Chair shall serve on the Management Team in a non-voting capacity for at least one year following the expiration of that person’s term as Chair. If an elected member of the Management Team resigns, or is no longer a member of NANOGrav, or is elected to the MT as a PI of a large grant, an election to replace that member shall be conducted as soon as reasonably possible, unless that position on the Management Team would have been vacated in less than six months.

The process for determining the significance of a new project:

  • During at least one general meeting, face-to-face or virtual, before the submission of a large proposal, the PI must present an overview of the proposed project to the collaboration and request membership on the MT for the duration of the award.
  • NANOGrav Full members will vote no more than one week after the PI presentation. A two-thirds majority vote will be required to instate the PI on the MT. The PI's tenure on the management team will begin on the official start date, and end on the official end date, of the proposal.

Descriptions and examples of large grants that would warrant PI membership in the MT:

  • A grant that provides funding for any NANOGrav activity to a majority of full members. This can include expenses for telescope time, data analysis, data curation, working group participation, publications, and travel to meetings. Funding for students and research associates who are not themselves full members but are mentored by a full member would be included.
  • A grant that covers telescope time for core NANOGrav observations even if the funding is channeled through a minority of institutions or to a minority of members. Examples: The PIRE grant from 2011-2015. Pending proposals that may lead to significant funding: CREST, Physics Frontier Center, Mid-Scale Innovations Program

Two Senior Personnel of NANOGrav shall serve on the IPTA Steering Committee in order to represent NANOGrav interests. One of the positions shall be designated to be also a member of the Management Team. The term of the IPTA Steering Committee representatives is two years,3 with one IPTA Steering Committee representative elected at the same time as the positions of the first class of the Management Team and the second representative elected at the same time as the positions of the second class of the Management Team.

If an IPTA Steering Committee representative resigns or is no longer a member of NANOGrav, an election to replace that representative shall be conducted as soon as reasonably possible, unless that position on the IPTA Steering Committee would have been vacated in less than six months.

The Management Team is responsible for conducting elections to all of these positions. Elections shall be scheduled such that there is at least one month between the date of the election and the date on which the term of the elected positions begins. One month prior to the date of an election, the Management Team shall identify the positions to be elected and notify the entire Collaboration by email that nominations for these positions can be submitted. A person may be nominated for multiple positions, but all nominations shall identify the position or positions for which a person is being nominated. The Management Team shall verify that all persons nominated for a position are eligible to serve in that position, if elected. Once the time for voting has expired, the Management Team shall notify the entire Collaboration by email of the persons elected to the positions as soon as reasonably possible, but no later than at least one week prior to the start of the new term of the positions.

4. Working Groups and committees


The Collaboration organizes its activities into a series of Working Groups (WGs). A new WG may be established by the agreement of three Full Members. Each WG shall appoint a chair, who will serve for a term of one year. A person may serve consecutive terms as a WG chair. Any Member of the Collaboration may join a WG by contacting the WG chair and requesting to join.

Ad-hoc, time-limited committees may be established, as needed, by the Management Team to research a specific issue, develop draft documents for discussion and approval by the Membership, or for other purposes as needed.

5. Meetings


NANOGrav shall conduct monthly meetings in order to assess progress toward its goals and review any scientific, technical, or programmatic issues that may have an impact on its goals. At least one meeting per year shall be in person, and other meetings may be in person or may use suitable technologies (e.g. teleconferencing, video conferencing, or web conferencing).

Each WG shall hold regular meetings, with a frequency of at least two meetings per year. Meetings may be in person or may use suitable technologies (e.g. teleconferencing, video conferencing, or web conferencing). All Members are welcome to participate in any WG meeting, even if not a formal member of that WG.

6. Voting


All votes shall be conducted by secret ballot. Votes shall be by email ballot or other suitable technical means (e.g. web poll). A minimum of one week shall be allowed for Members to transmit their votes. The quorum for a vote is two-thirds of the Members eligible to vote on the given question. A supermajority is defined as two-thirds of the votes cast.

For votes for Officer positions during elections, instant runoff voting shall be used. The election ballot shall list each position that is contested, with a slate of candidates for each position. The names of candidates shall be ordered alphabetically by their surnames. Each voter ranks the candidates for each position. In the first round, the top-ranked candidate on each ballot receives the vote. If a candidate receives a majority of the vote, he or she is elected to that position. If no candidate receives a majority, the candidate with the smallest number of votes is eliminated. The ballots of the eliminated candidate are assigned to one of the remaining candidates based on the next preference on each ballot. The process repeats until one candidate achieves a majority of votes cast.

To the extent possible, the Collaboration shall endeavor to act in a manner to develop consensus. If a consensus on an issue cannot be developed in a reasonable amount of time, the Chair may call for a vote on the issue. In any such vote, the motion is carried if a majority of the voting Full Members is in agreement.

For the following specific items, votes must be conducted with all Full Members being eligible to vote:

  • Election of the Chair of NANOGrav
  • Election of members of the NANOGrav Management Team
  • Election of NANOGrav representatives to the IPTA Steering Committee

For the following specific actions, votes must be conducted, with all Senior Personnel being eligible to vote and the motion being carried if a supermajority of the voting Senior Personnel is in agreement:

  • Adoption of any subsequent policies
  • Modification of these by-laws or of any policies

  • Ratification of these by-laws
  • Promotion of Associate Member to Full Membership
  • Involuntary conversion of a Full Member to Legacy membership
  • Expulsion of a member
  • Dissolution of NANOGrav

7. Proposals


The Collaboration shall be notified by email about any proposal for the purpose of obtaining funding for the detection or study of gravitational waves in which membership or participation in NANOGrav is referenced at least one month in advance of the proposal’s submission deadline. The notification shall contain at least the description of the funding opportunity and the working title of the proposal.

To the extent possible, the Collaboration shall be notified about any proposal to obtain observing time on North American telescopes for observations directly relevant to NANOGrav goals at least two weeks in advance of the proposal deadline, but no later than submission of the proposal itself. Any such proposal shall be circulated to the Collaboration as soon as possible prior to the deadline.

The individual who is anticipated to serve as Principal Investigator (PI) for the proposal shall provide the notification to NANOGrav. In the event that the proposal opportunity allows for multiple individuals to serve as Principal Investigators (co-PIs), one of the anticipated co-PIs shall provide the notification.

8. Policies and Procedures


The Collaboration may adopt policies for specific needs and describe procedures to implement them, as warranted, but no policy may be proposed that would contravene these by-laws. A policy may be proposed by the Management Team or by the agreement of three Full Members. At least two meetings of the NANOGrav Collaboration shall occur between the proposal of a policy and a vote to ratify it. Once adopted, policies may be amended in the same manner as these by-laws.

If any Member has reason to believe that procedures described in these by-laws or policies are not being followed correctly, that person is obligated to express his or her concerns to at least one member of the Management Team. The Management Team shall report to the Collaboration at the next meeting the nature of the concern, respecting confidentiality when necessary, and shall report to the Collaboration within a reasonable time the manner of its resolution.

9. Communications


NANOGrav shall maintain an email distribution list for the purpose of distributing notifications and other topics of interest to the entire Membership. Email distribution lists for subsets of NANOGrav members (e.g. Working Groups) may be established as needed. Other fora for the interchange and archiving of communications, documents, and data shall be established as necessary.

Any press release related to NANOGrav activities by a member’s institution shall be coordinated through the Public/Science Community Relations and Outreach WG.

10. Ratification and Amendments


An amendment to the by-laws may be suggested at any time by a Full Member. At least two meetings of the NANOGrav Collaboration shall occur between the proposal of an amendment and a vote to ratify it.

These by-laws shall come into force upon ratification by a supermajority vote of the Senior Personnel of NANOGrav.

11. Advisory Board


NANOGrav has a six-member External Advisory Board (EAB). The EAB meets with NANOGrav Senior Personnel twice yearly and advises the collaboration on its management, science progress, and strategic planning. The EAB submits a report to NANOGrav after each meeting, which may be shared by NANOGrav with external stakeholders at the collaboration's discretion. NANOGrav replies to this report no later than one month prior to the subsequent meeting. The EAB is also on hand to assist the collaboration throughout the year if the need arises. The members of the EAB are chosen by the Senior Personnel and will serve for two years unless removed by the MT. An EAB member may elect to step down at any time, but is encouraged to give the MT a minimum of one month’s notice. When a vacancy arises, any Senior Personnel member of NANOGrav may nominate a prospective replacement. If deemed suitable by the MT after taking into consideration such aspects as professional standing, synergy with current EAB members, and logistical considerations, the chair will announce the prospective EAB member at a following NANOGrav general meeting (either virtual or face-to-face). Within one week of the announcement, any Senior Personnel member may request a vote, which must occur no later then one month after the announcement of the prospective EAB member. The prospective EAB member will be instated to the EAB if 1) no vote was requested within the allotted time frame, or 2) there was a majority vote of the senior personnel members in favor of the prospective EAB member.

  • [1]At the time of writing of this document, the next term of the NANOGrav Chair begins on 2015 January 1.
  • [2]At the time of writing of this document, the current term of the Management Team members ends on 2013 December 31.
  • [3]At the time of writing of this document, the current term of one of the IPTA Steering Committee representatives ends on 2013 December 31 and the term of the other ends on 2014 December 31.

Publication Policy

1. Purpose


The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) is a collaboration of researchers who are actively engaged in using North American radio telescopes to detect and study gravitational waves via pulsar timing. The goals of this policy are

  • To ensure the timely dissemination of NANOGrav results
  • To ensure that members receive credit for critical NANOGrav work
  • To promote the open exchange of ideas within the Collaboration and foster collaboration among NANOGrav members
  • To publicize NANOGrav and its work in the broader scientific community
  • To increase awareness among all NANOGrav members of projects and publications within the Collaboration

2. Oversight


The NANOGrav Management Team is responsible for managing all aspects of the publication policy. The Management Team shall arbitrate and settle any publication dispute. Authors may appeal to the Management Team for exceptions to the publication policy in special cases. The Management Team may designate other NANOGrav members (individuals or committees) to act on their behalf in matters involving publication policy. In such instances, final decision-making power remains with the Management Team.

3. Coverage of Policy


This policy applies to Junior, Associate, and Full members of NANOGrav as defined by the membership policy.

The NANOGrav publication policy applies to “NANOGrav publications.” This includes all publications produced by NANOGrav members involving or motivated by NANOGrav data, pre-publication NANOGrav research and research results, or discussions that the members may have had as a privilege of their participation in the NANOGrav Collaboration. This also includes any publication related to NANOGrav science, or which uses NANOGrav-developed tools. The scope of “NANOGrav science” is broad and includes, but is not limited to, pulsar timing observations and data analysis for gravitational wave (GW) detection; detection techniques for GWs; astrophysical interpretation of pulsar timing array measurements; studies of noise in pulsar signals; and studies of the influence of the interstellar medium on pulsar signals.

Unless specified otherwise, this policy applies to all publications, independent of form or venue. This includes, but is not limited to, refereed journal articles, conference proceedings, technical memos, white papers, arXiv-only publications, and student papers.

4. IPTA Publications


Publications written under the auspices of the IPTA (International Pulsar Timing Array) shall follow IPTA authorship guidelines. We encourage such publications to follow policies similar to those for NANOGrav measurement/limit papers as outlined in Authorship.

5. Definitions and Types of Publications.


  1. Types of NANOGrav Science and Non-NANOGrav Science Publications
  2. Every publication covered by the NANOGrav publication policy falls into one of the following three categories.

    1. NANOGrav GW Measurement/Limit Publications
    2. A NANOGrav GW measurement/limit publication is a publication that uses NANOGrav data (and data products, time of arrival (TOA), residuals, par files) for the purposes of GW detection and/or upper limits (even if the data have been publicly released). Such publications include measurements/limits on GWs from any source or collection of sources, including backgrounds, individual periodic sources, and burst sources.

    3. NANOGrav Non-GW Measurement/Limit Publications
    4. This category includes all publications on NANOGrav science not giving GW measurements/limits. Such publications are on topics related to the NANOGrav goal of detecting, measuring, and extracting astrophysical information from GW signals using pulsar timing. Such publications include ISM studies, noise estimation in timing residuals, data analysis methods, detection techniques, astrophysical interpretation, etc.

    5. Non-NANOGrav Science Publications
    6. This category includes all publications which use NANOGrav resources as defined in Section 5.b but which are not on topics related to NANOGrav science as defined in Sections 5.a.i and 5.a.ii. An example of such a publication would be a paper using NANOGrav data to analyze a binary pulsar to measure neutron star masses.

  3. Publications Using NANOGrav Data

    Publications covered by the NANOGrav publication policy may (but need not) fall into one or both of the following categories. These definitions are used in authorship policies in Authorship.

    1. Publications Using NANOGrav Data
    2. A publication that uses NANOGrav data is any publication, whether or not on NANOGrav science as defined in Sections 5.a.i and 5.a.ii, that makes use of any data collected for the NANOGrav project, whether or not the data is available to the general public or to other collaborative groups. Such data includes, but is not limited to, pulsar timing array data, supplementary timing observations of individual timing array pulsars, and observations to study other aspects of pulsars that impact NANOGrav science (e.g. ISM studies, individual-pulse studies). The “data team” associated with any given data set are the NANOGrav members who obtained that data or processed it in ways necessary for its use in a publication.

    3. Publications Using NANOGrav Tools
    4. A publication that uses NANOGrav tools is any publication, whether or not on NANOGrav science as defined in Sections 5.a.i and 5.a.ii, that uses any software, simulation, or other tool developed for the NANOGrav project, whether or not that tool is publicly available. The “developers” associated with any given tool are the NANOGrav members who had a significant role in developing that tool.

6. Authorship


  1. NANOGrav GW Measurement/Limit Publications as Defined in Section 5.a.i
    1. The authorship of a NANOGrav measurement/limit publication, except for posters and presentations as described in first paragraph of Authorship, shall consist of NANOGrav Full Members, NANOGrav Legacy Members during their first year of Legacy status, and all others who contributed significantly to the publication. Authors shall be listed alphabetically in order of surname.
    2. Author lists for NANOGrav GW measurement/limit posters, oral presentations (e.g. seminars, colloquia, and conference presentations), and conference proceedings shall be authored by the presenter(s) for the NANOGrav Collaboration (e.g. “Jane Doe for the NANOGrav Collaboration”). Additional individual authors may be named only with approval of the Management Team.
  2. NANOGrav Non-GW Measurement/Limit Publications as Defined in Section 5.a.ii
    1. Author lists shall include all people who make significant contributions to the publication.
    2. Author lists may include specific groups as described in Sections 6.d.
    3. Author order shall be determined by the authors themselves. A typical situation may be a short list of those who make the most significant contributions to the publication followed by an alphabetical list of those with more ancillary roles.
    4. Author lists for posters, oral presentations, and conference proceedings that are NANOGrav non-GW-measurement/limit publications may include full author lists or may be abbreviated, e.g. “Jane Doe for the NANOGrav detection group” at the discretion of the authors.
  3. Publications Not on NANOGrav Science Using NANOGrav Resources as Defined in Section 5.a.iii
  4. Publications by NANOGrav members which use NANOGrav resources (data or tools) for non-NANOGrav science are subject to the authorship policies governing NANOGrav data and NANOGrav tools given in Section 6.d but are not governed by other authorship rules in the NANOGrav publication policy.

  5. Publications Using NANOGrav Data or Tools
    1. Publications that use NANOGrav data or NANOGrav tools that are not publicly available shall include the relevant data team or tool developers as authors.
    2. Publications that use NANOGrav data or NANOGrav tools that are publicly available should consult with the relevant data team or tool developers regarding potential co-authorship. For guidance, the corresponding author of a paper or the major participants in a project may consult with the Management Team.
    3. Publications that use small amounts of published NANOGrav data for illustrative purposes (e.g. for a new detection technique), but which do not present new GW limits/detections, need not include data-takers among the authors.
  6. authors may appeal to the Management Team for exceptions to the authorship policy as stated in Section 2

7. Conferences and Presentations


  1. Circulation of Abstracts, Titles, and Author Lists
    1. Conference and poster abstracts, titles, and author lists, for presentation on NANOGrav science topics as defined in Sections 5.a.i and 5.a.ii, shall be circulated to the NANOGrav Collaboration via email at least one week before submission to the conference organizers.
    2. Only abstracts for talks or posters on behalf of the NANOGrav Collaboration (i.e. “Jane Doe for the NANOGrav Collaboration”) shall require Management Team approval. Other types of abstracts for talks and posters do not require such approval, but should be circulated to the Collaboration as described in Section 7.a.i.
    3. All circulated abstracts shall be gathered on the NANOGrav document repository.
  2. Presentations Including a GW Measurement/Limit
    1. Circulation and Approval

      No poster or oral presentation (e.g. seminar, colloquium, conference presentation), nor any abstract for such, may make a quantitative statement about GW measurement/limits derived from NANOGrav data without the express approval of the Management Team, unless the result has already been published in an archival journal or on the arXiv, or unless the quantitative statement is on a list of approved measurement/limit statements maintained by the Management Team on the NANOGrav wiki. This approval must be obtained at least one week prior to the presentation. Any unpublished results shall be labeled as “preliminary.” Such presentations shall be circulated to the entire Collaboration, in draft form, one week before the presentation is given.

    2. Posting of Presentation Slides and Recordings
    3. Some conferences and seminar series routinely post presentation slides and/or video recordings of presentations on the Internet. Presentations that include NANOGrav GW measurement/limit statements that are part of such a conference or series may be posted on the Internet under the same restrictions described for presentations in Section 7.b.i.

    4. Conference Proceedings Including a GW Measurement/Limit
    5. Conference proceedings that are NANOGrav GW measurement/limit publications may not be submitted until the main NANOGrav GW detection/upper limit paper that describes the results is on the arXiv or published.

  3. Archiving of Presentations
  4. All presentations shall be gathered on the NANOGrav document repository.

8. Student Publications


  1. Definition
  2. A “student publication” is a thesis (graduate or undergraduate), term paper, or other publication primarily or exclusively written by a student for submission to an educational institution for academic purposes.

  3. Authorship
  4. Student publications may be authored by a single author (the student). Such publications shall acknowledge other contributors to the work.

  5. Student Publications Including a GW Measurement/Limit
  6. Student publications shall not be the first presentation of a new GW measurement or new astrophysically significant GW upper limit.

  7. Circulation
  8. Student publications shall be circulated to the Collaboration one week before submission. The purpose of circulation is to make the Collaboration aware of the student work and to allow the student to receive feedback on the publication. However, the student supervisor, not the Collaboration, is ultimately responsible for reviewing student work.

9. Review and Submission Procedures


  1. A corresponding author shall be designated by those working most closely on any given publication in consultation with the Management Team.
  2. The corresponding author is charged with ensuring that the NANOGrav review and submission procedures are followed for the publication.
  3. The corresponding author along with the co-authors working most closely on the publication have the responsibility for the entire paper as an accurate, verifiable, report on the research.
  4. Publications which do not arise from pre-existing projects should be placed on the project list in a timely manner.
  5. Circulation
    1. Rough draft manuscripts shall be circulated within the NANOGrav Collaboration for a minimum of one week for discussion of major content issues.
    2. Draft manuscripts shall be circulated within NANOGrav for a minimum of one additional week for discussion of minor content issues, for a total of at least two weeks of circulation before submission to a journal (or publication in another form).
    3. Early and frequent circulation of outlines and manuscripts is strongly encouraged, however. The circulation time-scales in Sections 9.e.i and 9.e.ii should be regarded as an absolute minimum.
    4. All Collaboration members may suggest changes to the content and author list.
    5. Non-authors may not distribute draft manuscripts further without permission of authors.
  6. The corresponding author shall share editorial correspondence with all other authors on any given publication (not necessarily the full NANOGrav Collaboration).
  7. If major changes in content are required during the refereeing process, the manuscript shall be circulated as described in Section 9.e.
  8. For refereed papers, the corresponding author shall notify the NANOGrav Collaboration when the paper is accepted.
    1. A database of NANOGrav publications with bibliographic information shall be maintained.

10. Project List


  1. Student and other projects by NANOGrav members on NANOGrav related science shall be listed on the NANOGrav wiki.
  2. Such projects, including graduate student projects, shall be protected from prior publication by others provided the project is completed in timely manner.
  3. The status and progress of all unfinished projects and unpublished publications, including graduate student projects, shall be reviewed at regular intervals by the Working Group (WG) chairs who shall report to the Management Team.
  4. Anyone who has made significant contributions to a project in NANOGrav forums and WGs may propose themselves as an author on papers which arise from that project.
  5. Information about projects in progress shall not be circulated beyond the NANOGrav Collaboration except by the project team.

This material is based in part on work supported by the National Science Foundation under Grant Number 968296. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.