| 1. |
- Blanton, Michael R., et al.
(författare)
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Sloan Digital Sky Survey IV : Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
- 2017
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Ingår i: Astronomical Journal. - : IOP Publishing Ltd. - 0004-6256 .- 1538-3881. ; 154:1
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Tidskriftsartikel (refereegranskat)abstract
- We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and. high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z similar to 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z similar to 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs. and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the. Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July.
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| 2. |
- Abolfathi, Bela, et al.
(författare)
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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
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Ingår i: Astrophysical Journal Supplement Series. - : IOP Publishing Ltd. - 0067-0049 .- 1538-4365. ; 235:2
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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.
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| 3. |
- Gaffney, K J, et al.
(författare)
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Observation of structural anisotropy and the onset of liquidlike motion during the nonthermal melting of InSb
- 2005
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 95:12
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Tidskriftsartikel (refereegranskat)abstract
- The melting dynamics of laser excited InSb have been studied with femtosecond x-ray diffraction. These measurements observe the delayed onset of diffusive atomic motion, signaling the appearance of liquidlike dynamics. They also demonstrate that the root-mean-squared displacement in the [111] direction increases faster than in the [110] direction after the first 500 fs. This structural anisotropy indicates that the initially generated fluid differs significantly from the equilibrium liquid.
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| 4. |
- Lindenberg, AM, et al.
(författare)
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Atomic-scale visualization of inertial dynamics
- 2005
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 308:5720, s. 392-395
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Tidskriftsartikel (refereegranskat)abstract
- The motion of atoms on interatomic potential energy surfaces is fundamental to the dynamics of liquids and solids. An accelerator-based source of femtosecond x-ray pulses allowed us to follow directly atomic displacements on an optically modified energy landscape, leading eventually to the transition from crystalline solid to disordered liquid. We show that, to first order in time, the dynamics are inertial, and we place constraints on the shape and curvature of the transition-state potential energy surface. Our measurements point toward analogies between this nonequilibrium phase transition and the short-time dynamics intrinsic to equilibrium liquids.
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| 5. |
- Sampaio, J. M., et al.
(författare)
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Simulation of (125) I Auger emission spectrum with new atomic parameters from MCDHF calculations
- 2022
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier. - 0022-4073 .- 1879-1352. ; 277
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Tidskriftsartikel (refereegranskat)abstract
- New 125 I atomic decay emission data of medical interest are presented. The calculations are based on two atomic structure codes that implement the multi-configuration Dirac-Hartree-Fock method. Radiative and non-radiative ransition rates are calculated in this method and then used to generate the atomic deexcitation cascade. Subshell transition rates, level widths and fluorescence yields are compared to the Evaluated Atomic Data Library. Coster-Kronig and Auger electron emission yields are also compared with results from other authors. The comparison with the experimental electron emission spectrum shows that the new calculations can reproduce very well the structure of the K-LL Auger electron peaks and improve the description of the M Auger peaks below 300 eV. The 125 I dose-point kernel is also simulated using the new data, resulting in higher values below 10 nm when compared those obtained with the Evaluated Atomic Data Library.
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| 6. |
- Tee, B. P. E., et al.
(författare)
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Development of a new database for Auger electron and X-ray spectra
- 2020
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Ingår i: HEAVY ION ACCELERATOR SYMPOSIUM (HIAS 2019). - : EDP Sciences.
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Konferensbidrag (refereegranskat)abstract
- An energy correction method is described to account for the Breit and QED effects on Auger electrons and X-ray energies in the recently developed atomic relaxation model BrIccEmis. The results are compared with literature and new experimental data for Z = 52. Overall this improves the agreement of the calculated energies with the literature values. A new atomic radiation database NS_Radlist, will contain atomic transition energies from the BrIccEmis program with these energy corrections.
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| 7. |
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The Seventeenth Data Release of the Sloan Digital Sky Surveys : Complete Release of MaNGA, MaStar, and APOGEE-2 Data
- 2022
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Ingår i: Astrophysical Journal Supplement Series. - : Institute of Physics (IOP). - 0067-0049 .- 1538-4365. ; 259:2
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Tidskriftsartikel (refereegranskat)abstract
- This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys.
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| 8. |
- Berglund, Mats, et al.
(författare)
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Perceived Risk for Cannabis, Tobacco and Alcohol : Comparison of US and Swedish High School Students
- 2014
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Ingår i: Alcoholism. - : John Wiley & Sons. - 0145-6008 .- 1530-0277. ; 38:s1, s. 347A-347A
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Aims: Perceived risk is related to use of cannabis, alcohol, and tobacco among youth. Sweden and US have different policies and customs related to these substances thatmay influence both risk perception and behavior regarding use of these substances. Differences in perceived risk of cannabis, cigarettes, chewing tobacco and alcohol in Sweden and the US have been reported but no direct systematic comparison has been performed. Design and setting: The ATLAS Project is a long-term longitudinal study comparing the development of substance use from high school to the young adult life period (18–23 years) in the US and Sweden. Participants: Baseline data for 3352 17–19 year-old high school students (65%from Sweden, 56% women, mean age 17.8, 35%from US 58%women,mean age 17.6). Measurements: Surveys of perceived risk items, ever use of cannabis, cigarettes and alcohol, as well as conduct problems, mental health symptoms, and impulsivity. Findings: The largest differences between the countries were found for the risk of cannabis use. Swedish participants reported much higher perceived risk both for continuous and occasional use than US students. For cigarettes, chewing tobacco and alcohol students from the US reported higher risk perception than the Swedish students did. Females reported higher perceived risk for all substances than male students.Conduct problems were associated with less perceived risk in all examples and impulsivity in cannabis and alcohol issues. Increasedmental health symptoms were associated with increased perceived risk for alcohol. Those who have used the specific drug reported lower levels of risk for that drug butmostly not for other drugs. Conclusions: Perceived risk for cannabis was higher in Swedish students than in US students while cigarette smoking, chewing tobacco and alcohol use were perceived as more risky in the US. One possibility could be that Sweden has much tougher drug laws than the US while less stringent alcohol and tobacco laws.
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| 9. |
- Fossos-Wong, Nicole, et al.
(författare)
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Changes in Alcohol Expectancies, Drinking and Alcohol-Related Negative Consequences in the Transition out of High School
- 2014
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Ingår i: Alcoholism. - : John Wiley & Sons. - 0145-6008 .- 1530-0277. ; 38:s1, s. 59A-59A
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The transition fromadolescence to emerging adulthood is a period of increased risk for heavy drinking behavior. Prior research has found that college students drink more and experience more consequences than their non-college counterparts. However, sparse research has examined whether students who are college- versus work-bound show differences in drinking and related consequences in high school (HS) as well. In addition, little research has explored whether alcohol expectancies also change over time as a function of selection into college versus non-college environments. The current study examined whether alcohol-related expectancies, consequences, and drinking changed over the course of a year as a function of whether participants transitioned into a four-year university (UNI), community college/trade school (CC), or workforce setting (WF). Participants (N=848) were HS seniors (mean age=17.5 years; 37%male, 73%Caucasian) taking part in a larger study examining alcohol use trajectories.Measures included alcohol expectancies (CEOA), drinking (DDQ), and alcohol-related problems (RAPI) assessed during their senior year and one year later. Repeatedmeasures ANOVAs revealed significant main effects for time, indicating increases in drinks per week F(1, 807)=19.18, p>0.001 and alcohol-related problems F(1, 808)=8.78, p>0.01 and a decrease in alcohol expectancies F(1, 808)=14.35, p>0.001 from baseline to 12 month follow-up. Results also found a main effect for group, indicating UNI students held higher expectancies F(2, 808)=8.15, p>0.001 and drank more F(2, 807)=6.26, p>0.01 than other participants. A significant time9group interaction showed that whereas UNI-bound students drank less thanWF-bound students in HS, the roles reversed one year later with UNI students drinking more thanWF students F (2, 807)=27.56, p>0.001. Similarly, WF-bound students had more alcohol-related problems in HS followed by CC-bound students and UNI-bound students, but one year later the order reversed with UNI students exhibiting the most alcohol-related problems F(2, 807)=5.21, p>0.01. Results indicate that whereas UNI-bound seniors exhibit the highest expectancies, drink less, and experience fewer problems during HS, upon entry into UNI, they experience more problems and out-drink their CC andWF counterparts. These results highlight the importance of prevention strategies, including an expectancy challenge component, especially for UNI-bound HS seniors.
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| 10. |
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