1. |
- Abelev, Betty, et al.
(författare)
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Long-range angular correlations on the near and away side in p-Pb collisions at root S-NN=5.02 TeV
- 2013
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 719:1-3, s. 29-41
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Tidskriftsartikel (refereegranskat)abstract
- Angular correlations between charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV for transverse momentum ranges within 0.5 < P-T,P-assoc < P-T,P-trig < 4 GeV/c. The correlations are measured over two units of pseudorapidity and full azimuthal angle in different intervals of event multiplicity, and expressed as associated yield per trigger particle. Two long-range ridge-like structures, one on the near side and one on the away side, are observed when the per-trigger yield obtained in low-multiplicity events is subtracted from the one in high-multiplicity events. The excess on the near-side is qualitatively similar to that recently reported by the CMS Collaboration, while the excess on the away-side is reported for the first time. The two-ridge structure projected onto azimuthal angle is quantified with the second and third Fourier coefficients as well as by near-side and away-side yields and widths. The yields on the near side and on the away side are equal within the uncertainties for all studied event multiplicity and p(T) bins, and the widths show no significant evolution with event multiplicity or p(T). These findings suggest that the near-side ridge is accompanied by an essentially identical away-side ridge. (c) 2013 CERN. Published by Elsevier B.V. All rights reserved.
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2. |
- Abelev, Betty, et al.
(författare)
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Measurement of prompt J/psi and beauty hadron production cross sections at mid-rapidity in pp collisions at root s=7 TeV
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.
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3. |
- Abelev, Betty, et al.
(författare)
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Underlying Event measurements in pp collisions at root s=0.9 and 7 TeV with the ALICE experiment at the LHC
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :7
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of Underlying Event observables in pp collisions at root s = 0 : 9 and 7 TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p(T),L-T in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p(T) thresholds: 0.15, 0.5 and 1.0 GeV/c. In the Transverse region we observe an increase in the multiplicity of a factor 2-3 between the lower and higher collision energies, depending on the track p(T) threshold considered. Data are compared to PYTHIA 6.4, PYTHIA 8.1 and PHOJET. On average, all models considered underestimate the multiplicity and summed p(T) in the Transverse region by about 10-30%.
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5. |
- Lomax, Johanna, et al.
(författare)
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Luminescence based loess chronostratigraphy of the Upper Palaeolithic site Krems-Wachtberg, Austria
- 2014
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Ingår i: Quaternary International. - : Elsevier BV. - 1040-6182 .- 1873-4553. ; 351, s. 88-97
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Tidskriftsartikel (refereegranskat)abstract
- The loess section Krems-Wachtberg (Lower Austria) is well known for its Upper Palaeolithic find layer, which contains a double and a single infant burial. The layer containing the grave (archaeological horizon AH 4.4) was dated to 26,580 +/- 160 C-14 BP (Einwogerer et al., 2006), corresponding to ca. 31 ka cal BP and is embedded in an 8 m thick loess sequence. In order to provide a chronostratigraphy of the entire section, 38 samples for luminescence dating were taken at high resolution from below and above the find layer. The samples were dated using the quartz coarse grain fraction, the quartz fine grain fraction and/or the polymineral fine grain fraction. The resulting ages are in correct chronostratigraphic order and, in case samples were measured with different protocols, agree within errors with each other and with the radiocarbon age of the find layer. The polymineral fine grain ages are systematically slightly lower than the quartz ages, although no fading could be detected in laboratory experiments. Loess deposition at the site commenced ca. 40 ka ago and reaches up to ca. 22 ka. The ages indicate nearly continuous loess sedimentation throughout this time span. Short breaks in sedimentation probably exist but cannot be resolved due to the uncertainties of luminescence ages.
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6. |
- Zanker, Markus, et al.
(författare)
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An Autometed Approach for Deriving Semantic Annotations of Tourism Products based on Geo-Spatial Information
- 2009
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Ingår i: Information and Communication Technologies in Tourism 2009 Proceedings of the International Conference in Amsterdam, The Netherlands, 2009. - Viennna New York : Springer. - 9783211939703 ; , s. 211-221
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Konferensbidrag (refereegranskat)abstract
- High quality product data is a necessary prerequisite for supporting efficient browsing and recommendation procedures on e-commerce platforms. This is especially true for the tourism domain where an abundance of information can easily overwhelm users. Although classification data such as to which category (e.g. accommodation, restaurant or sight) a tourism product belongs is usually directly available, qualitative information, such as proximity to a lake or opportunities for dining or shopping, is rarely provided in a structured way. As a consequence, users can not restrict their search on these criteria; rather, it would require costly manual information acquisition efforts. In this paper we propose a knowledge-based approach that automatically associates such qualitative concepts with tourism products based on their geographic coordinates and their spatial proximity. An initial evaluation of the approach that considered automatically generated annotations within different regions suggests that it can be used as an alternative to domain experts.
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7. |
- Zanker, Markus, et al.
(författare)
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Automated semantic annotation of tourism resources based on geo-spatial data
- 2009
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Ingår i: Information Technology & Tourism. - New York; Sydney; Tokyo : Cognizant Communication Corp.. - 1098-3058 .- 1943-4294. ; 11:4, s. 341-354
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Tidskriftsartikel (refereegranskat)abstract
- Web 2.0 applications, now common in the tourism domain, make it easy to share travel related experiences and opinions, thus, leading to the creation of enormous amounts of user generated content. This type of tourist information must, however, be preprocessed by structuring and aggregating it in order to avoid overwhelming users. In this article we, therefore, propose a knowledge-based approach that exploits spatial proximity to annotate resources with qualitative semantic concepts for tourism products, such as proximity to a lake or opportunities for specific sporting activities. Finally, the article describes the successful prototypical implementation of the proposed technique and provides insight into a practical usage scenario
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8. |
- Aguilar-Pimentel, Juan Antonio, et al.
(författare)
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Increased estrogen to androgen ratio enhances immunoglobulin levels and impairs B cell function in male mice.
- 2020
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Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Sex steroids, such as estrogens and androgens, are important regulators of the humoral immune response. Studies in female mice have demonstrated that alteration of circulating estrogen concentration regulates antibody-mediated immunity. As males have normally little endogenous estrogen, we hypothesized that in males high estrogens and low androgens affect the immune system and enhance the allergic inflammatory response. Here, we studied transgenic male mice expressing human aromatase (AROM+). These animals have a high circulating estrogen to androgen ratio (E/A), causing female traits such as gynecomastia. We found that AROM+ male mice had significantly higher plasma immunoglobulin levels, particularly IgE. Flow cytometry analyses of splenocytes revealed changes in mature/immature B cell ratio together with a transcriptional upregulation of the Igh locus. Furthermore, higher proliferation rate and increased IgE synthesis after IgE class-switching was found. Subsequently, we utilized an ovalbumin airway challenge model to test the allergic response in AROM+ male mice. In line with above observations, an increase in IgE levels was measured, albeit no impact on immune cell infiltration into the lungs was detected. Together, our findings suggest that high circulating E/A in males significantly alters B cell function without any significant enhancement in allergic inflammation.
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9. |
- Botan, Alexandru, et al.
(författare)
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Toward Atomistic Resolution Structure of Phosphatidylcholine Headgroup and Glycerol Backbone at Different Ambient Conditions
- 2015
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 119:49, s. 15075-15088
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Tidskriftsartikel (refereegranskat)abstract
- Phospholipids are essential building blocks of biological membranes. Despite a vast amount of very accurate experimental data, the atomistic resolution structures sampled by the glycerol backbone and choline headgroup in phoshatidylcholine bilayers are not known. Atomistic resolution molecular dynamics simulations have the potential to resolve the structures, and to give an arrestingly intuitive interpretation of the experimental data, but only if the simulations reproduce the data within experimental accuracy. In the present work, we simulated phosphatidylcholine (PC) lipid bilayers with 13 different atomistic models, and compared simulations with NMR. experiments in terms of the highly structurally sensitive C-H bond vector order parameters. Focusing on the glycerol backbone and choline headgroups, we showed that the order parameter comparison can be used to judge the atomistic resolution structural accuracy of the models. Accurate models, in turn, allow molecular dynamics simulations to be used as an interpretation tool that translates these NMR data into a dynamic three-dimensional representation of biomolecules in biologically relevant conditions. In addition to lipid bilayers in fully hydrated conditions, we reviewed previous experimental data for dehydrated bilayers and cholesterol-containing bilayers, and interpreted them with simulations. Although none of the existing models reached experimental accuracy, by critically comparing them we were able to distill relevant chemical information: (1) increase of choline order parameters indicates the P-N vector tilting more parallel to the membrane, and (2) cholesterol induces only minor changes to the PC (glycerol backbone) structure. This work has been done as a fully open collaboration, using nmrlipids.blogspot.fi as a communication platform; all the scientific contributions were made publicly on this blog. During the open research process, the repository holding our simulation trajectories and files (https://zenodo.org/collection/user-nmrlipids) has become the most extensive publicly available collection of molecular dynamics simulation trajectories of lipid bilayers.
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