Search results for " usi"
showing 10 items of 88 documents
Macroalgal responses to ocean acidification depend on nutrient and light levels
2015
Ocean acidification may benefit algae that are able to capitalize on increased carbon availability for photosynthesis, but it is expected to have adverse effects on calcified algae through dissolution. Shifts in dominance between primary producers will have knock-on effects on marine ecosystems and will likely vary regionally, depending on factors such as irradiance (light vs. shade) and nutrient levels (oligotrophic vs. eutrophic). Thus experiments are needed to evaluate interactive effects of combined stressors in the field. In this study, we investigated the physiological responses of macroalgae near a CO2 seep in oligotrophic waters off Vulcano (Italy). The algae were incubated in situ …
Seagrass ecosystem response to long-term high CO2 in a Mediterranean volcanic vent
2014
We examined the long-term effect of naturally acidified water on a Cymodocea nodosa meadow growing at a shallow volcanic CO2 vent in Vulcano Island (Italy). Seagrass and adjacent unvegetated habitats growing at a low pH station (pH = 7.65 ± 0.02) were compared with corresponding habitats at a control station (pH = 8.01 ± 0.01). Density and biomass showed a clear decreasing trend at the low pH station and the below- to above-ground biomass ratio was more than 10 times lower compared to the control. C content and delta 13C of leaves and epiphytes were significantly lower at the low pH station. Photosynthetic activity of C. nodosa was stimulated by low pH as seen by the significant increase in…
Seawater carbonate chemistry and coralline algal diversity
2021
Calcified coralline algae are ecologically important in rocky habitats in the marine photic zone worldwide and there is growing concern that ocean acidification will severely impact them. Laboratory studies of these algae in simulated ocean acidification conditions have revealed wide variability in growth, photosynthesis and calcification responses, making it difficult to assess their future biodiversity, abundance and contribution to ecosystem function. Here, we apply molecular systematic tools to assess the impact of natural gradients in seawater carbonate chemistry on the biodiversity of coralline algae in the Mediterranean and the NW Pacific, link this to their evolutionary history and …
Decline in Coccolithophore Diversity and Impact on Coccolith Morphogenesis Along a Natural CO2 Gradient
2014
A natural pH gradient caused by marine CO2 seeps off Vulcano Island (Italy) was used to assess the effects of ocean acidification on coccolithophores, which are abundant planktonic unicellular calcifiers. Such seeps are used as natural laboratories to study the effects of ocean acidification on marine ecosystems, since they cause long-term changes in seawater carbonate chemistry and pH, exposing the organisms to elevated CO2 concentrations and therefore mimicking future scenarios. Previous work at CO2 seeps has focused exclusively on benthic organisms. Here we show progressive depletion of 27 coccolithophore species, in terms of cell concentrations and diversity, along a calcite saturation …
Shallow water marine sediment bacterial community shifts along a natural CO2 gradient in the Mediterranean Sea Off vulcano, Italy
2014
The effects of increasing atmospheric CO(2) on ocean ecosystems are a major environmental concern, as rapid shoaling of the carbonate saturation horizon is exposing vast areas of marine sediments to corrosive waters worldwide. Natural CO(2) gradients off Vulcano, Italy, have revealed profound ecosystem changes along rocky shore habitats as carbonate saturation levels decrease, but no investigations have yet been made of the sedimentary habitat. Here, we sampled the upper 2 cm of volcanic sand in three zones, ambient (median pCO(2) 419 µatm, minimum Omega (arag) 3.77), moderately CO(2)-enriched (median pCO(2) 592 µatm, minimum Omega (arag) 2.96), and highly CO(2)-enriched (median pCO(2) 1611…
Il direttore d'orchestra nel sistema produttivo del teatro d'opera italiano di fine Ottocento. Un caso eloquente: Emilio Usiglio a Firenze nel 1892
2014
Attraverso l'analisi dei sistemi che regolarono l'organizzazione di una stagione operistica a Firenze nel 1892, l'articolo riflette sulla progressiva affermazione del direttore d'orchestra come figura centrale della macchina produttiva.
Iepazīšanās portāla lietošanas motīvi un personības tumšā triāde
2020
Pētījuma mērķis bija noskaidrot kāda sakarība pastāv starp iepazīšanās portālu lietošanas motīviem un tumšās triādes personības iezīmēm. Pētījumā piedalījās 686 Latvijas iepazīšanās portāla Otrapuse.lv lietotāji, 420 sievietes un 266 vīrieši. Pētījumā tika uzmantotas divas aptaujas: Īsā tumšās triādes skala (Short Dark Triad Scale, Jones & Paulhus, 2014). Latvijā metodi adaptējusi Laima Baldiņa (Baldiņa, 2017); Iepazīšanās portāla Otrapuse.lv lietošanas motīvi aptauja ( Tinder Motives Scale (TMS), Timmermans & De Caluwé, 2017). Aptauja tika adaptēta maģistra darba ietvaros. Pētījumā izvirzītie jautājumi: 1. Kāda sakarība pastāv starp iepazīšanās portāla lietošanas motīviem un tumšās triādes…
Meeting the Discipline-Culture Framework of Physics Knowledge: A Teaching Experience in Italian Secondary School
2014
The paper deals with physics teaching/learning in high school. An investigation in three upper secondary school classes in Italy explored the reactions of students to a structuring lecture on optics within the discipline-culture (DC) framework that organises physics knowledge around four interrelated fundamental theories of light. The lecture presented optics as an unfolding conceptual discourse of physicists regarding the nature of light. Along with the knowledge constructed in a school course of a scientific lyceum, the students provided epistemological comments, displaying their perception of physics knowledge presented in the classroom. Students’ views and knowledge were investigated by…
Nella giostra della social photography
2018
Oggi la fotografia va ben oltre la fissazione dei ricordi. Il volume riprende la nota ricerca di Bourdieu relativa agli usi sociali della fotografia intorno alla metà degli anni Sessanta. Da questa si desume che un tempo gli scatti dei non professionisti, mediati dall'habitus di classe, intercettavano i momenti topici della vita sociale e le tipicità espresse da una cultura condivisa. Mentre le foto dei professionisti aspiravano a riconoscere i momenti decisivi in senso autoriale in vari ambiti (reportage, moda, paesaggio, pubblicità ). Oggi, in virtù dell'accelerazione sociale, siamo incerti sulla direzione della Storia. Tutti i fenomeni sono potenzialità del mondo, come tutte le immagini …
Procne e Filomela. Dal mito al simbolo letterario
2005
Una monografia sulla saga di Procne e Filomela da Omero a Ovidio, esaminata in primo luogo dal punto di vista mitografico, nello sviluppo delle diverse versioni del mito, quindi da quello metaletterario, in relazione alla metafora del poeta-usignolo e al suo percorso dalla letteratura greca arcaica alla letteratura latina di età augustea A monograph on the saga of Procne and Philomela from Homer to Ovid, surveyed first from a mythological point of view - taking into account the development of the myth's different versions -, then from a metaliterary one, following the path of the poet-nightingale metaphor from archaic Greek literature to augustan Latin literature.