Institution
University of Rijeka
Education•Rijeka, Croatia•
About: University of Rijeka is a education organization based out in Rijeka, Croatia. It is known for research contribution in the topics: Population & Tourism. The organization has 3471 authors who have published 7993 publications receiving 110386 citations. The organization is also known as: Rijeka University & Sveučilište u Rijeci.
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TL;DR: In this article, the spectral energy distribution of 3C 279, the first quasar discovered to emit VHE gamma-rays by the MAGIC telescope in 2006, was reobserved by MAGIC in January 2007 during a major optical flare and from December 2008 to April 2009 following an alert from the Fermi space telescope on an exceptionally high gamma-ray state.
Abstract: Context. 3C 279, the first quasar discovered to emit VHE gamma-rays by the MAGIC telescope in 2006, was reobserved by MAGIC in January 2007 during a major optical flare and from December 2008 to April 2009 following an alert from the Fermi space telescope on an exceptionally high gamma -ray state.
Aims. The January 2007 observations resulted in a detection on January 16 with significance 5.2 sigma, corresponding to a F(> 150 GeV) (3.8 \pm 0.8) \cdot 10^-11 ph cm^-2 s^-1 while the overall data sample does not show significant signal. The December 2008 - April 2009 observations did not detect the source. We study the multiwavelength behavior of the source at the epochs of MAGIC observations, collecting quasi-simultaneous data at optical and X-ray frequencies and for 2009 also gamma-ray data from Fermi.
Methods. We study the light curves and spectral energy distribution of the source. The spectral energy distributions of three observing epochs (including the February 2006, which has been previously published in Albert et al. 2008a) are modeled with one-zone inverse Compton models and the emission on January 16, 2007 also with two zone model and with a lepto-hadronic model.
Results. We find that the VHE gamma-ray emission detected in 2006 and 2007 challenges standard one-zone model, based on relativistic electrons in a jet scattering broad line region photons, while the other studied models fit the observed spectral energy distribution more satisfactorily.
92 citations
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TL;DR: In this article, the MAGIC telescopes were used to detect very high energy gamma-rays from IC 310, a head-tail radio galaxy in the Perseus galaxy cluster, observed during the interval November 2008 to February 2010.
Abstract: We report on the detection with the MAGIC telescopes of very high energy gamma-rays from IC 310, a head-tail radio galaxy in the Perseus galaxy cluster, observed during the interval November 2008 to February 2010. The Fermi satellite has also detected this galaxy. The source is detected by MAGIC at a high statistical significance of 7.6sigma in 20.6 hr of stereo data. The observed spectral energy distribution is flat with a differential spectral index of -2.00 \pm 0.14. The mean flux above 300 GeV, between October 2009 and February 2010, (3.1 \pm 0.5)x10^{-12} cm^{-2} s^{-1}, corresponds to (2.5 \pm 0.4)% of Crab Nebula units. Only an upper limit, of 1.9% of Crab Nebula units above 300 GeV, was obtained with the 2008 data. This, together with strong hints (>3sigma) of flares in the middle of October and November 2009, implies that the emission is variable. The MAGIC results favour a scenario with the very high energy emission originating from the inner jet close to the central engine. More complicated models than a simple one-zone SSC scenario, e.g. multi-zone SSC, external Compton or hadronic, may be required to explain the very flat spectrum and its extension over more than three orders of magnitude in energy.
92 citations
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TL;DR: The presented data indicate clear regional differences of biochemical changes caused by lithium plus pilocarpine treatment and the resulting status epilepticus, frontal cortex being the most affected site.
90 citations
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TL;DR: In this article, a conceptual model incorporating perceived service quality, customer-perceived value, and repurchase intention in a higher education context was proposed and tested, and empirical data were collected among undergraduate students in Bosnia and Herzegovina and Croatia to assess the overall fit of the proposed model and to test hypotheses using covariance-based structural equation modelling.
Abstract: The present study proposed and tested a conceptual model incorporating perceived service quality, customer-perceived value, and repurchase intention in a higher-education context. The main purpose was to empirically investigate the relationships between these concepts; thus, three hypotheses were postulated. Empirical data were collected among undergraduate students in Bosnia and Herzegovina and Croatia. A total of 735 cases were used to assess the overall fit of the proposed model and to test hypotheses using covariance-based structural equation modelling. The results support the proposed conceptual model, showing that perceived service quality and customer-perceived value have a positive and significant influence on repurchase intention, as well as that perceived service quality has a positive and significant impact on customer-perceived value. Therefore, the study contributes to the existing literature reporting the findings on quality and value in an educational context, with evidence from South Easte...
90 citations
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TL;DR: It is demonstrated that the balance between rRNA and ribosomal protein synthesis controls the function of p53 in mammalian cells, that p53 can be induced without the occurrence of severe changes of the cellular components controlling ribosome biogenesis, and that conditions characterised by an upregulated rRNA synthesis are associated with a reduced p53 response.
Abstract: Data on the relationship between ribosome biogenesis and p53 function indicate that the tumour suppressor can be activated by either nucleolar disruption or ribosomal protein defects. However, there is increasing evidence that the induction of p53 does not always require these severe cellular changes, and data are still lacking on a possible role of ribosome biogenesis in the downregulation of p53. Here, we studied the effect of the up- and downregulation of the rRNA transcription rate on p53 induction in mammalian cells. We found that a downregulation of rRNA synthesis, induced by silencing the POLR1A gene coding for the RNA polymerase I catalytic subunit, stabilised p53 without altering the nucleolar integrity in human cancer cells. p53 stabilisation was due to the inactivation of the MDM2-mediated p53 degradation by the binding of ribosomal proteins no longer used for ribosome building. p53 stabilisation did not occur when rRNA synthesis downregulation was associated with a contemporary reduction of protein synthesis. Furthermore, we demonstrated that in three different experimental models characterised by an upregulation of rRNA synthesis, cancer cells treated with insulin or exposed to the insulin-like growth factor 1, rat liver stimulated by cortisol and regenerating rat liver after partial hepatectomy, the p53 protein level was reduced due to a lowered ribosomal protein availability for MDM2 binding. It is worth noting that the upregulation of rRNA synthesis was responsible for a decreased p53-mediated response to cytotoxic stresses. These findings demonstrated that the balance between rRNA and ribosomal protein synthesis controls the function of p53 in mammalian cells, that p53 can be induced without the occurrence of severe changes of the cellular components controlling ribosome biogenesis, and that conditions characterised by an upregulated rRNA synthesis are associated with a reduced p53 response.
90 citations
Authors
Showing all 3537 results
Name | H-index | Papers | Citations |
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Igor Rudan | 142 | 658 | 103659 |
Nikola Godinovic | 138 | 1469 | 100018 |
Ivica Puljak | 134 | 1436 | 97548 |
Damir Lelas | 133 | 1354 | 93354 |
D. Mekterovic | 110 | 449 | 46779 |
Ulrich H. Koszinowski | 96 | 281 | 27709 |
Michele Doro | 79 | 437 | 20090 |
Robert Zivadinov | 73 | 522 | 18636 |
D. Dominis Prester | 70 | 363 | 16701 |
Daniel Ferenc | 70 | 225 | 16145 |
Vladimir Parpura | 64 | 226 | 18050 |
Stipan Jonjić | 62 | 227 | 19363 |
Dario Hrupec | 60 | 288 | 13345 |
Alessandro Laviano | 59 | 298 | 14609 |
Tomislav Terzić | 58 | 271 | 10699 |