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- Adcox, K, et al.
(författare)
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Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX Collaboration
- 2005
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Ingår i: Nuclear Physics, Section A. - : Elsevier BV. - 0375-9474. ; 757:1-2, s. 184-283
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Forskningsöversikt (refereegranskat)abstract
- Extensive experimental data from high-energy nucleus-nucleus collisions were recorded using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The comprehensive set of measurements from the first three years of RHIC operation includes charged particle multiplicities, transverse energy, yield ratios and spectra of identified hadrons in a wide range of transverse momenta (PT), elliptic flow, two-particle correlations, nonstatistical fluctuations, and suppression of particle production at high PT. The results are examined with an emphasis on implications for the formation of a new state of dense matter. We find that the state of matter created at RHIC cannot be described in terms of ordinary color neutral hadrons.
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| 2. |
- Adler, Patrick, et al.
(författare)
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The city and high-tech startups : The spatial organization of Schumpeterian entrepreneurship
- 2019
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Ingår i: Cities. - : Pergamon Press. - 0264-2751 .- 1873-6084. ; 87:April, s. 121-130
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Tidskriftsartikel (refereegranskat)abstract
- Research on Schumpeterian entrepreneurship identifies new high-growth startup companies as key factors in technological innovation and economic growth. While economists have tended to focus on high-growth, high-tech startup firms as the unit of analysis, economic geographers and urbanists have examined the geographic dimensions of entrepreneurship, particularly the rise of entrepreneurial clusters and eco systems. We focus here on a particular type of Schumpeterian entrepreneurship associated with high-tech startup companies, or what we refer to as “tech-startup entrepreneurship.†We contend that the organization of such Schumpeterian entrepreneurship occurs at two spatial scales. At the macro-geographic level, it is highly clustered and concentrated in a relatively small number of global cities or metro areas. At the micro-geographic level, it is highly concentrated in distinct districts or micro-clusters within these leading cities and metro areas. To examine the geographic dimensions of tech-startup entrepreneurship across these spatial scales, we use previously unused data on venture capital-financed startups at the metropolitan and district levels. Our findings support the hypothesis that tech-startup entrepreneurship is organized across two distinct but related spatial scales, which act on entrepreneurial activity through different mechanisms. These findings suggest that local diversity and local specialization can simultaneously potentiate innovation, and that a multi-scalar approach to the geography of entrepreneurship is prudent.
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| 3. |
- Adler, SS, et al.
(författare)
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Double helicity asymmetry in inclusive midrapidity pi(0) production for polarized p+p collisions at root s=200 GeV
- 2004
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Ingår i: Physical Review Letters. - 1079-7114. ; 93:20: 202002
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Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the double longitudinal spin asymmetry in inclusive pi(0) production in polarized proton-proton collisions at roots=200 GeV. The data were taken at the Relativistic Heavy Ion Collider with average beam polarizations of 0.27. The measurements are the first in a program to study the longitudinal spin structure of the proton, using strongly interacting probes, at collider energies. The asymmetry is presented for transverse momenta 1-5 GeV/c at midrapidity, where next-to-leading-order perturbative quantum chromodynamic (NLO pQCD) calculations well describe the unpolarized cross section. The observed asymmetry is small and is compared to a NLO pQCD calculation with a range of polarized gluon distributions.
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| 6. |
- Adler, Sven
(författare)
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Effects of counting variances on water quality assessments: implications from four benthic diatom samples, each counted by 40 diatomists
- 2016
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Ingår i: Journal of Applied Phycology. - : Springer Science and Business Media LLC. - 0921-8971 .- 1573-5176. ; 28, s. 2287-2297
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Tidskriftsartikel (refereegranskat)abstract
- The European Water Framework Directive (EU WFD) aims to improve and maintain the water quality of lakes and rivers. Diatoms play an important role for implementing the EU WFD as they are widely used to assess water quality. To asses and use diatom-based evaluations in practice, it is essential to know and to minimize the analyst-dependent variability of the primary diatom results. We compare the counting results of benthic diatoms from two river and two lake samples as identified by 40 participants of the first German benthic diatom intercalibration exercise. Differences among participants and auditors are calculated with the Bray-Curtis distance, and similarities are graphically displayed by detrended correspondence analyses. Additionally, this study identifies the effects of counting variances on the ecological water assessment with the German PHYLIB method for implementing the EU WFD using the above dataset. Counting result differences among participants may have a significant impact on the assessed water quality. Some taxonomically problematic taxa do not have indicator values (no impact), sometimes, several taxonomic mistakes counterbalance each other during assessment (no or minor impact), and sometimes, taxonomic differences greatly influence the assessment due to highly deviating taxon abundances and/or strongly differing indicator values between mistaken taxa. Intercalibration exercises promote discussion about taxonomy, identify problematic taxa, and harmonize taxonomic concepts among diatomists. Thus, the shown analyst-induced variability of diatom counts may be reduced with an intercalibration exercise, thereby further refining the accuracy of water quality assessments.
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| 9. |
- Adcox, K, et al.
(författare)
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Centrality dependence of the high (PT) charged hadron suppression in Au+Au collisions at root s(NN)=130 GeV
- 2003
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 561:1-2, s. 82-92
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Tidskriftsartikel (refereegranskat)abstract
- PHENIX has measured the centrality dependence of charged hadron p(T) spectra from Au +An collisions at root(s)NN = 130 GeV The truncated mean p(T) decreases with centrality for p(T) > 2 GeV/c, indicating an apparent reduction of the contribution from hard scattering to high p(T) hadrdn production. For central collisions the yield at high p(T) is shown to be suppressed compared to binary nucleon-nucleon collision scaling of p + p, data. This suppression is monotonically increasing with centrality, but most of the change occurs below 30% centrality, i.e., for collisions with less than similar to140 participating nucleons. The observed p(T) and centrality dependence is consistent with the particle production predicted by models including hard scattering and subsequent energy loss of the scattered partons in the dense matter created in the collisions. (C) 2003 Published by Elsevier Science B.V.
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