91. The excess of phosphorus in soil reduces physiological performances over time but enhances prompt recovery of salt-stressed Arundo donax plantsClaudia Cocozza, Federico Brilli, Sara Pignattelli, Susanna Pollastri, Cecilia Brunetti, Cristina Gonnelli, Roberto Tognetti, Mauro Centritto, Francesco Loreto, 2020, izvirni znanstveni članek Opis: Arundo donax L. is an invasive grass species with high tolerance to a wide range of environmental stresses. The
response of potted A. donax plants to soil stress characterized by prolonged exposure (43 days) to salinity (+Na),
to high concentration of phosphorus (+P), and to the combination of high Na and P (+NaP) followed by 14 days
of recovery under optimal nutrient solution, was investigated along the entire time-course of the experiment.
After an exposure of 43 days, salinity induced a progressive decline in stomatal conductance that hampered A.
donax growth through diffusional limitations to photosynthesis and, when combined with high P, reduced the
electron transport rate. Isoprene emission from A. donax leaves was stimulated as Na+ concentration raised in
leaves. Prolonged growth in P-enriched substrate did not significantly affect A. donax performance, but decreased
isoprene emission from leaves. Prolonged exposure of A. donax to + NaP increased the leaf level of
H2O2, stimulated the production of carbohydrates, phenylpropanoids, zeaxanthin and increased the de-epoxidation
state of the xanthophylls. This might have resulted in a higher stress tolerance that allowed a fast and full
recovery following stress relief. Moreover, the high amount of ABA-glucose ester accumulated in leaves of A.
donax exposed to + NaP might have favored stomata re-opening further sustaining the observed prompt recovery
of photosynthesis. Therefore, prolonged exposure to high P exacerbated the negative effects of salt stress
in A. donax plants photosynthetic performances, but enhanced activation of physiological mechanisms that allowed
a prompt and full recovery after stress. Ključne besede: Arundo donax
Phosphorus
Salinity
Stress tolerance
Biomass production Objavljeno v RUNG: 20.04.2020; Ogledov: 3083; Prenosov: 0 Gradivo ima več datotek! Več... |
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93. Looking for a topological insulator in the tetradymite familyZipporah Rini Benher, Sandra Gardonio, Mattia Fanetti, Polina M. Sheverdyaeva, Paolo Moras, Matjaž Valant, 2019, objavljeni povzetek znanstvenega prispevka na konferenci Opis: Materials that are topological insulators (TI) manifest a novel state for their electrons. They possess topological surface states that are not destroyed by the presence of non-magnetic impurities on their surfaces. This unique property lies in the bulk band structure and it is typically found in narrow gap semiconductor with strong spin-orbit coupling.
Bi2Se3 and Bi2Te3 belong to the class of compounds called tetradymites and are considered as the 3D-prototypical TI materials. However, these compounds are not usually insulators but have metallic bulk conductivity as a consequence of intrinsic defect doping: vacancies and anti-site defects. For these reasons, it is difficult to electrically gate these materials for the manipulation and control of charge carriers for realizing devices. This led to the search for other topological materials, which might have better insulating behavior in their bulk.
Theoretical studies have pointed out that ternary variants of the Bi2Se3 and Bi2Te3, such as Bi2Te2Se, Bi2Te2S, Bi2Se2S Sb2Te2Se and Sb2Te2S, should be stable TIs and potentially offer a chemical way to control TI behavior, in particular by lowering native doping. Among the cited ternary compounds, Bi2Se2S should manifest a genuine topological spin-transport regime hosting an isolated Dirac cone with the Dirac point in the gap as well. However, it has been poorly studied from the TI experimental perspective.
Therefore, to uncover the full potential of the predicted topological electronic properties of the Bi-Se-S system, in this presentation we will revisit the crystallographic and electronic structure of Bi2Se3-Bi2S3 solid solutions. The combined use of bulk and surface sensitive techniques such as X-ray diffraction (XRD), low energy electron diffraction (LEED), scanning electron microscopy (SEM) with Energy Dispersive X-ray spectroscopy (EDX) and X-ray photoemission spectroscopy (XPS) was applied to analyze single crystal samples grown by us. The quality of the single crystals was suitable for rigorous measurement of the electronic properties by means of Angle Resolved Photoemission Spectroscopy. We unambiguously showed that within a certain solid solution range, the single crystals of Bi-Se-S have a rombohedral structure with the topological surface states as theoretically predicted. Ključne besede: topological insulators, ternary tetradymite, electronic properties. Objavljeno v RUNG: 19.12.2019; Ogledov: 4059; Prenosov: 0 Gradivo ima več datotek! Več... |
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95. STUDY OF ELECTRONIC STATES OF THIN METAL FILMS ON HEAVY METAL SURFACES : MASTER'S THESISLuka Novinec, 2018, magistrsko delo Opis: V magistrskem delu smo se osredoto£ili na pripravo in karakterizacijo
heterogenih ve£plastnih tankih filmov sestavljenih iz kovin ter teºkih kovin.
Za izdelavo vzorcev smo izbrali dve feromagnetni kovini, Fe in Gd, ter
eno divalentno kovino iz redkih zemelj, Yb. Tanke filme smo nana²ali na
kristalno povr²ino volframa W(110) ter molibdena Mo(110). V primeru Fe
na povr²ini W(110) in Mo(110) ter Yb na pov²ini Mo(110) smo uspe²no
dolo£ili pogoje, potrebne za nana²anje atomsko enakomernih filmov. S pomo
£jo kotno odvisne fotoemisije smo preu£evali kvantna stanja v Fe in Yb
filmih na Mo in W kristalih. Celotno eksperimentalno delo je potekalo na
ºarkovnih linijah VUV-Photoemission in²tituta (ISM-CNR) ter BaDElPh
pri sinhrotronu Elettra v Trstu. Ključne besede: electronic states, thin metal films, heavy metal surfaces Objavljeno v RUNG: 04.12.2019; Ogledov: 4268; Prenosov: 106 Celotno besedilo (25,10 MB) |
96. A consensus protocol for the in silico optimisation of antibody fragmentsMiguel Soler, Barbara Medagli, Marta S. Semrau, Paola Storici, Gregor Bajc, Ario De Marco, Alessandro Laio, Sara Fortuna, 2019, izvirni znanstveni članek Ključne besede: nanobodies, in silico design, Her2 Objavljeno v RUNG: 21.11.2019; Ogledov: 3384; Prenosov: 0 Gradivo ima več datotek! Več... |
97. Synthesis of adsorbent-free ultrathin Bi2Se3 Topological Insulator Platelets and Its Inherent Surface PropertiesBlaž Belec, Katja Ferfolja, Tanja Goršak, Nina Kostevšek, Sandra Gardonio, Mattia Fanetti, Matjaž Valant, 2019, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: Bismuth selenide, topological insulator, hydrothermal synthesis, surface properties Objavljeno v RUNG: 30.09.2019; Ogledov: 3532; Prenosov: 0 Gradivo ima več datotek! Več... |
98. Multi-wavelength aerosol absorption coefficient measurements: instrument inter-comparison and results of source and source-component modellingVera Bernardoni, Luca Ferrero, Francesca Soldan, Sara Valentin, Mario Massabò, Griša Močnik, Asta Gregorič, Marco Cataldi A., Ezio Bolzacchini, Paolo Prati, Gianluigi Valli, Roberta Vecchi, 2019, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: aerosol absorption, method intercomparison Objavljeno v RUNG: 17.07.2019; Ogledov: 3668; Prenosov: 0 Gradivo ima več datotek! Več... |
99. Au and Ag on the Bi2Se3(0001) Surface: Experimental Electronic and Physical PropertiesSandra Gardonio, Mattia Fanetti, Katja Ferfolja, Matjaž Valant, objavljeni povzetek znanstvenega prispevka na konferenci Opis: Binary bismuth chalcogenides, Bi2Se3 and Bi2Te3, have been extensively studied as reference topological
insulators (TIs). These materials are bulk insulators with topological surface states (TSS) crossing the
Fermi level. In contrast to conventional surface states of metals, the TSS are extremely robust
against local modifications at the surface, such as adsorbed adatoms, localized defects or changes in the surface termination. This aspect makes the TIs attractive for applications in spintronics, plasmonics, quantum computing and catalysis.
A theoretical model of charge transport by the TI surface states predicts that the TSS survive, provided that bonding at the metal/TI interface is weak. Ab-initio calculations have been done to understand the electronic properties of Au, Ni, Pt, Pd and graphene layers in a contact with Bi2Se3. These calculations showed that for Au and graphene the spin-momentum locking of TSS is maintained at the interface. In another theoretical study, Ag and Au thin layers on Bi2Se3 have been predicted to show a large Rashba splitting and a high spin polarization of the Ag quantum wells, providing a great potential for development of the spintronic devices. Finally, the calculations have foreseen that the presence of the robust TSS affects the adsorption properties of metals (Au bi-layer and clusters of Au, Ag, Cu, Pt, and Pd) supported on TI, in some cases resulting in the enhancement of the catalytic processes.
Despite the fundamental importance of the metal/TI interfaces and a number of theoretical studies
predicting exotic interfacial phenomena, the experimental knowledge about the metals on the TI surfaces is surprisingly limited, especially concerning combined study of morphology, growth mode, electronic and chemical properties.
In order to exploit the predicted physical properties of such systems, it is especially important to extend the study above the diluted coverage regime and to understand what is the growth morphology of the metal on the TI surface, to what extent the metal overlayer interacts with the TI substrate, how the TSS change with the presence of the metal overlayer and what is the reactivity of the system at the different stages of the overlayer growth.
Within this frame, we present a comprehensive surface sensitive study, of Au and Ag on Bi2Se3 by means of ARPES, XPS, SEM, LEED and XRD. The obtained results allow us to discuss the relation between electronic and physical properties at two of the most important model metal/TI interfaces Ključne besede: topological insulator, electronic properties, synchrotron radiation Objavljeno v RUNG: 27.06.2019; Ogledov: 3494; Prenosov: 0 Gradivo ima več datotek! Več... |
100. Anomaly detection in processing of complex syntax by early L2 learnersArthur Stepanov, Sara Andreetta, Penka Stateva, Adam Zawiszewski, Itziar Laka, 2019, izvirni znanstveni članek Opis: This study investigates the processing of long-distance syntactic dependencies by native speakers of Slovenian (L1) who are advanced learners of Italian as a second language (L2), compared with monolingual Italian speakers. Using a self-paced reading task, we compare sensitivity of the early-acquired L2 learners to syntactic anomalies in their L2 in two empirical domains: (1) syntactic islands, for which the learners’ L1 and L2 grammars provide a converging characterization, and (2) verb–clitic constructions, for which the respective L1 and L2 grammatical descriptions diverge. We find that although our L2 learners show native-like processing patterns in the former, converging, grammatical domain, they may nevertheless perform non-native-like with respect to syntactic phenomena in which the L1 and L2 grammars do not align, despite the early age of L2 acquisition. Implications for theories of L2 acquisition and endstate are discussed. Ključne besede: bilingualism, clitic, Italian, sentence processing, Slovenian, syntactic island Objavljeno v RUNG: 21.02.2019; Ogledov: 4013; Prenosov: 113 Celotno besedilo (597,08 KB) |