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- 2019
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Journal article (peer-reviewed)
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| 2. |
- Antoniazza, Sylvain, et al.
(author)
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Local adaptation maintains clinal variation in melanin-based coloration of European barn owls (Tyto alba).
- 2010
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In: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 64:7, s. 1944-1954
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Journal article (peer-reviewed)abstract
- Ecological parameters vary in space, and the resulting heterogeneity of selective forces can drive adaptive population divergence. Clinal variation represents a classical model to study the interplay of gene flow and selection in the dynamics of this local adaptation process. Although geographic variation in phenotypic traits in discrete populations could be remainders of past adaptation, maintenance of adaptive clinal variation requires recurrent selection. Clinal variation in genetically determined traits is generally attributed to adaptation of different genotypes to local conditions along an environmental gradient, although it can as well arise from neutral processes. Here, we investigated whether selection accounts for the strong clinal variation observed in a highly heritable pheomelanin-based color trait in the European barn owl by comparing spatial differentiation of color and of neutral genes among populations. Barn owl's coloration varies continuously from white in southwestern Europe to reddish-brown in northeastern Europe. A very low differentiation at neutral genetic markers suggests that substantial gene flow occurs among populations. The persistence of pronounced color differentiation despite this strong gene flow is consistent with the hypothesis that selection is the primary force maintaining color variation among European populations. Therefore, the color cline is most likely the result of local adaptation.
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| 3. |
- Arpaia, Riccardo, 1985, et al.
(author)
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Dynamical charge density fluctuations pervading the phase diagram of a Cu-based high-Tc superconductor
- 2019
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 365:6456, s. 906-910
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Journal article (peer-reviewed)abstract
- Charge density modulations have been observed in all families of high–critical temperature (Tc) superconducting cuprates. Although they are consistently found in the underdoped region of the phase diagram and at relatively low temperatures, it is still unclear to what extent they influence the unusual properties of these systems. Using resonant x-ray scattering, we carefully determined the temperature dependence of charge density modulations in YBa2Cu3O7–d and Nd1+xBa2–xCu3O7–d for several doping levels. We isolated short-range dynamical charge density fluctuations in addition to the previously known quasi-critical charge density waves. They persist up to well above the pseudogap temperature T*, are characterized by energies of a few milli–electron volts, and pervade a large area of the phase diagram.
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| 4. |
- Baiocchi, Gian Luca, et al.
(author)
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International consensus on a complications list after gastrectomy for cancer
- 2019
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In: Gastric Cancer. - : Springer Science and Business Media LLC. - 1436-3291 .- 1436-3305. ; 22:1, s. 172-189
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Journal article (peer-reviewed)abstract
- Background: Perioperative complications can affect outcomes after gastrectomy for cancer, with high mortality and morbidity rates ranging between 10 and 40%. The absence of a standardized system for recording complications generates wide variation in evaluating their impacts on outcomes and hinders proposals of quality-improvement projects. The aim of this study was to provide a list of defined gastrectomy complications approved through international consensus. Methods: The Gastrectomy Complications Consensus Group consists of 34 European gastric cancer experts who are members of the International Gastric Cancer Association. A group meeting established the work plan for study implementation through Delphi surveys. A consensus was reached regarding a set of standardized methods to define gastrectomy complications. Results: A standardized list of 27 defined complications (grouped into 3 intraoperative, 14 postoperative general, and 10 postoperative surgical complications) was created to provide a simple but accurate template for recording individual gastrectomy complications. A consensus was reached for both the list of complications that should be considered major adverse events after gastrectomy for cancer and their specific definitions. The study group also agreed that an assessment of each surgical case should be completed at patient discharge and 90 days postoperatively using a Complication Recording Sheet. Conclusion: The list of defined complications (soon to be validated in an international multicenter study) and the ongoing development of an electronic datasheet app to record them provide the basic infrastructure to reach the ultimate goals of standardized international data collection, establishment of benchmark results, and fostering of quality-improvement projects.
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| 5. |
- Braicovich, Lucio, et al.
(author)
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Determining the electron-phonon coupling in superconducting cuprates by resonant inelastic x-ray scattering: Methods and results on Nd1+xBa2-xCu3O7-δ
- 2020
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In: Physical Review Research. - 2643-1564. ; 2:2
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Journal article (peer-reviewed)abstract
- The coupling between lattice vibration quanta and valence electrons can induce charge-density modulations and decisively influence the transport properties of materials, e.g., leading to conventional superconductivity. In high-critical-temperature superconductors, where electronic correlation is the main actor, the actual role of electron-phonon coupling (EPC) is being intensely debated theoretically and investigated experimentally. We present an in-depth study of how the EPC strength can be obtained directly from resonant inelastic x-ray scattering (RIXS) data through the theoretical approach derived by Ament et al. [Europhys. Lett. 95, 27008 (2011)]. The role of the model parameters (e.g., phonon energy ω0, intermediate state lifetime 1/Γ, EPC matrix element M, and detuning energy Ω) is thoroughly analyzed, providing general relations among them that can be used to make quantitative estimates of the dimensionless EPC g=(M/ω0)2 without detailed microscopic modeling. We then apply these methods to very high-resolution Cu L3-edge RIXS spectra of three Nd1+xBa2−xCu3O7−δ films. For the insulating antiferromagnetic parent compound, the value of M as a function of the in-plane momentum transfer is obtained for Cu-O bond-stretching (breathing) and bond-bending (buckling) phonon branches. For the underdoped and the nearly optimally doped samples, the effects of Coulomb screening and of charge-density-wave correlations on M are assessed. In light of the anticipated further improvements of the RIXS experimental resolution, this work provides a solid framework for an exhaustive investigation of the EPC in cuprates and other quantum materials.
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| 6. |
- Burri, Reto, et al.
(author)
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Adaptive divergence of ancient gene duplicates in the avian MHC class II beta
- 2010
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In: Molecular biology and evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 27:10, s. 2360-2374
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Journal article (peer-reviewed)abstract
- Gene duplication and neofunctionalization are known to be important processes in the evolution of phenotypic complexity. They account for important evolutionary novelties that confer ecological adaptation, such as the major histocompatibility complex (MHC), a multigene family crucial to the vertebrate immune system. In birds, two MHC class II β (MHCIIβ) exon 3 lineages have been recently characterized, and two hypotheses for the evolutionary history of MHCIIβ lineages were proposed. These lineages could have arisen either by 1) an ancient duplication and subsequent divergence of one paralog or by 2) recent parallel duplications followed by functional convergence. Here, we compiled a data set consisting of 63 MHCIIβ exon 3 sequences from six avian orders to distinguish between these hypotheses and to understand the role of selection in the divergent evolution of the two avian MHCIIβ lineages. Based on phylogenetic reconstructions and simulations, we show that a unique duplication event preceding the major avian radiations gave rise to two ancestral MHCIIβ lineages that were each likely lost once later during avian evolution. Maximum likelihood estimation shows that following the ancestral duplication, positive selection drove a radical shift from basic to acidic amino acid composition of a protein domain facing the α-chain in the MHCII α β-heterodimer. Structural analyses of the MHCII α β-heterodimer highlight that three of these residues are potentially involved in direct interactions with the α-chain, suggesting that the shift following duplication may have been accompanied by coevolution of the interacting α- and β-chains. These results provide new insights into the long-term evolutionary relationships among avian MHC genes and open interesting perspectives for comparative and population genomic studies of avian MHC evolution.
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| 7. |
- Burri, Reto, et al.
(author)
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Evolutionary patterns of MHC class II B in owls and their implications for the understanding of avian MHC evolution
- 2008
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In: Molecular biology and evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 25:6, s. 1180-1191
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Journal article (peer-reviewed)abstract
- Owing to its special mode of evolution and central role in the adaptive immune system, the major histocompatibility complex (MHC) has become the focus of diverse disciplines such as immunology, evolutionary ecology, and molecular evolution. MHC evolution has been studied extensively in diverse vertebrate lineages over the last few decades, and it has been suggested that birds differ from the established mammalian norm. Mammalian MHC genes evolve independently, and duplication history (i.e., orthology) can usually be traced back within lineages. In birds, this has been observed in only 3 pairs of closely related species. Here we report strong evidence for the persistence of orthology of MHC genes throughout an entire avian order. Phylogenetic reconstructions of MHC class II B genes in 14 species of owls trace back orthology over tens of thousands of years in exon 3. Moreover, exon 2 sequences from several species show closer relationships than sequences within species, resembling transspecies evolution typically observed in mammals. Thus, although previous studies suggested that long-term evolutionary dynamics of the avian MHC was characterized by high rates of concerted evolution, resulting in rapid masking of orthology, our results question the generality of this conclusion. The owl MHC thus opens new perspectives for a more comprehensive understanding of avian MHC evolution.
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| 8. |
- Burri, Reto, et al.
(author)
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Isolation and characterization of major histocompatibility complex (MHC) class II B genes in the Barn owl (Aves: Tyto alba)
- 2008
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In: Immunogenetics. - : Springer Science and Business Media LLC. - 0093-7711 .- 1432-1211. ; 60:9, s. 543-550
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Journal article (peer-reviewed)abstract
- We isolated major histocompatibility complex class II B (MHCIIB) genes in the Barn owl (Tyto alba). A PCR-based approach combined with primer walking on genomic and complementary DNA as well as Southern blot analyses revealed the presence of two MHCIIB genes, both being expressed in spleen, liver, and blood. Characteristic structural features of MHCIIB genes as well as their expression and high non-synonymous substitution rates in the region involved in antigen binding suggest that both genes are functional. MHC organization in the Barn owl is simple compared to passerine species that show multiple duplications, and resembles the minimal essential MHC of chicken.
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| 9. |
- Burri, Reto, et al.
(author)
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The genetic basis of color-related local adaptation in a ring-like colonization around the Mediterranean
- 2016
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In: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 70:1, s. 140-153
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Journal article (peer-reviewed)abstract
- Uncovering the genetic basis of phenotypic variation and the population history under which it established is key to understand the trajectories along which local adaptation evolves. Here, we investigated the genetic basis and evolutionary history of a clinal plumage color polymorphism in European barn owls (Tyto alba). Our results suggest that barn owls colonized the Western Palearctic in a ring-like manner around the Mediterranean and meet in secondary contact in Greece. Rufous coloration appears to be linked to a recently evolved nonsynonymous-derived variant of the melanocortin 1 receptor (MC1R) gene, which according to quantitative genetic analyses evolved under local adaptation during or following the colonization of Central Europe. Admixture patterns and linkage disequilibrium between the neutral genetic background and color found exclusively within the secondary contact zone suggest limited introgression at secondary contact. These results from a system reminiscent of ring species provide a striking example of how local adaptation can evolve from derived genetic variation.
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| 10. |
- Campos, Jaime, et al.
(author)
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Business Performance Measurements in Asset Management with the Support of Big Data Technologies
- 2017
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In: Management Systems in Production Engineering. - : De Gruyter Open. - 2299-0461 .- 2450-5781. ; 25:3, s. 143-149
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Journal article (peer-reviewed)abstract
- The paper reviews the performance measurement in the domain of interest. Important data in asset management are further, discussed. The importance and the characteristics of today’s ICTs capabilities are also mentioned in the paper. The role of new concepts such as big data and data mining analytical technologies in managing the performance measurements in asset management are discussed in detail. The authors consequently suggest the use of the modified Balanced Scorecard methodology highlighting both quantitative and qualitative aspects, which is crucial for optimal use of the big data approach and technologies.
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