| 1. |
- Abolfathi, Bela, et al.
(författare)
-
The Fourteenth Data Release of the Sloan Digital Sky Survey : First Spectroscopic Data from the Extended Baryon Oscillation Spectroscopic Survey and from the Second Phase of the Apache Point Observatory Galactic Evolution Experiment
- 2018
-
Ingår i: Astrophysical Journal Supplement Series. - : IOP Publishing Ltd. - 0067-0049 .- 1538-4365. ; 235:2
-
Tidskriftsartikel (refereegranskat)abstract
- The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since 2014 July. This paper describes the second data release from this phase, and the 14th from SDSS overall (making this Data Release Fourteen or DR14). This release makes the data taken by SDSS-IV in its first two years of operation (2014-2016 July) public. Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey; the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data-driven machine-learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from the SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS web site (www.sdss.org) has been updated for this release and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020 and will be followed by SDSS-V.
|
|
| 2. |
- Hinde, D. J., et al.
(författare)
-
Systematic study of quasifission characteristics and timescales in heavy element formation reactions
- 2016
-
Ingår i: 12th International Conference on Nucleus-Nucleus Collisions 2015. - : EDP Sciences.
-
Konferensbidrag (refereegranskat)abstract
- Superheavy elements can only be created in the laboratory by the fusion of two massive nuclei. Mass-angle distributions give the most direct information on the characteristics and time scales of quasifission, the major competitor to fusion in these reactions. The systematics of 42 mass-angle distributions provide information on the global characteristics of quasifission. Deviations from the systematics reveal the major role played by the nuclear structure of the two colliding nuclei in determining the reaction outcome, and in hindering or favouring heavy element production.
|
|
| 3. |
- Hinde, D. J., et al.
(författare)
-
Quasifission in heavy and superheavy element formation reactions
- 2016
-
Ingår i: Nobel Symposium NS 160 – Chemistry and Physics of Heavy and Superheavy Elements. - : EDP Sciences.
-
Konferensbidrag (refereegranskat)abstract
- Superheavy elements are created in the laboratory by the fusion of two heavy nuclei. The large Coulomb repulsion that makes superheavy elements decay also makes the fusion process that forms them very unlikely. Instead, after sticking together for a short time, the two nuclei usually come apart, in a process called quasifission. Mass-angle distributions give the most direct information on the characteristics and time scales of quasifission. A systematic study of carefully chosen mass-angle distributions has provided information on the global trends of quasifission. Large deviations from these systematics reveal the major role played by the nuclear structure of the two colliding nuclei in determining the reaction outcome, and thus implicitly in hindering or favouring superheavy element production.
|
|
| 4. |
- Hinde, D. J., et al.
(författare)
-
Sub-barrier quasifission in heavy element formation reactions with deformed actinide target nuclei
- 2018
-
Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 97:2
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The formation of superheavy elements (SHEs) by fusion of two massive nuclei is severely inhibited by the competing quasifission process. Lowexcitation energies favor SHE survival against fusion-fission competition. In "cold" fusion with spherical target nuclei near Pb-208, SHE yields are largest at beam energies significantly below the average capture barrier. In "hot" fusion with statically deformed actinide nuclei, this is not the case. Here the elongated deformation-aligned configurations in sub-barrier capture reactions inhibits fusion (formation of a compact compound nucleus), instead favoring rapid reseparation through quasifission. Purpose: To determine the probabilities of fast and slow quasifission in reactions with prolate statically deformed actinide nuclei, through measurement and quantitative analysis of the dependence of quasifission characteristics at beam energies spanning the average capture barrier energy. Methods: The Australian National University Heavy Ion Accelerator Facility and CUBE fission spectrometer have been used to measure fission and quasifission mass and angle distributions for reactions with projectiles from C to S, bombarding Th and U target nuclei. Results: Mass-asymmetric quasifission occurring on a fast time scale, associated with collisions with the tips of the prolate actinide nuclei, shows a rapid increase in probability with increasing projectile charge, the transition being centered around projectile atomic number ZP = 14. For mass-symmetric fission events, deviations of angular anisotropies from expectations for fusion fission, indicating a component of slower quasifission, suggest a similar transition, but centered around ZP similar to 8. Conclusions: Collisions with the tips of statically deformed prolate actinide nuclei show evidence for two distinct quasifission processes of different time scales. Their probabilities both increase rapidly with the projectile charge. The probability of fusion can be severely suppressed by these two quasifission processes, since the sub-barrier heavy element yield is likely to be determined by the product of the probabilities of surviving each quasifission process.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Ursu, Marian F, et al.
(författare)
-
Interactive TV Narratives : Opportunities, Progress and Challenges
- 2008
-
Ingår i: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP). - : Transactions on Multimedia Computing, Communications, and Applications (TOMCAAP). - 1551-6857 .- 1551-6865. ; 4:4
-
Tidskriftsartikel (refereegranskat)abstract
- This paper is motivated by the question whether television should do more than simply offer interactive services alongside (and separately from) traditional linear programmes, in the context of its dominance being seriously challenged and threatened by interactive forms of screen media entertainment. It suggests: yes. Interactive narrativity, i.e. the ability to interact with (and influence) stories whilst they are being told, represents one clear development-path for interactive television. The capabilities of computing technology are ripe for exploring this new form of storytelling, from creation to commercial distribution. The paper starts with looking at the relationship between narrativity and interactivity in the current context of screen media, and identifies clear signs of interest from certain European public broadcasters in interactive TV narratives. It then presents in detail four recent experimental interactive TV productions in the genres of drama, news, and documentary, developed in collaboration with public broadcasters, which illustrate the potential and richness of this new form of storytelling, but also highlight new technological capabilities necessary for such productions. A number of essential technological requirements are then discussed in more detail in the final part. The paper suggests that the ShapeShifting Media Technology, employed in the implementation of the four productions, has made significant advances both at the technological and the creative ends in supporting the development of interactive TV narrativity, but, however, that further developments are required before being able to answer questions such as “would end users want such a form of screen media entertainment?” and “would it be effective for both end-users and producers?”
|
|
