326,157 research outputs found
Effects of long-term light acclimation on Photosystem II functional antenna size and excitonic connectivity in Selaginella martensii.
No full textLycophyte division is composed of ancient vascular plants that diverged from euphyllophyte lineage ca. 400 million years ago. Among these, Selaginella martensii Spring has evolved to inhabit shade environments of tropical-equatorial rainforests. However, this plant is also able to acclimate efficiently to light regimes as different as deep shade and full sunlight (Ferroni et al. 2016, 2021). Such characteristic reveals a marked flexibility of the photosynthetic machinery in response to the light availability, but the underlying structural and dynamic acclimation features have been clarified only partially. In fact, differently from most seed plants, S. martensii is unable to modulate the content of Photosystem II antenna complexes (LHCII), which remains constant from deep shade to full sunlight regime, while the ratio between PSII and PSI decreases. In order to clarify the light acclimation features in S. martensii under deep-shade (L), intermediate shade (M) and full sunlight (H), we analyzed some functional aspects of light harvesting and electron transport after the plants' exposure to dark for 20 minutes, far red (FR) light for 20 minutes and moderate light for 1 hour. The analysis was performed using a HandyPEA (Hansatech, UK) fluorometer, which allowed us to calculate the JIP-test parameters. Among these, we particularly focused on ABS/RC, i.e. the functional antenna size of a PSII unit (Stirbet and Govindjee 2011). We also used the fluorescence transients to calculate the PSII excitonic connectivity parameters, which describe the probability of excitation transfer between different PSII units (Stirbet 2013). Our results suggest that the acclimation to different light regimes influences both PSII functional antenna size and PSII connectivity, but the direction of changes apparently contrasted with expectations. On one hand, the PSII antenna size was only slightly variable from L to H plants. On the other hand, PSII connectivity was in general far lower when compared to common values reported for seed plants. Especially H plants reported connectivity values close to 0, suggesting a "puddle" organization of PSII
Della vera curva degli archi del ponte a S. Trinità di Firenze
No full textdiscorso geometrico-storico del Sig. Pietro Ferroni"Inserito nel tomo XIV della Società Italiana delle Scienze"Handschriftliches Exlibris: "Duc de Coseane No. 41" 990005792960205503_0001 Exemplar der ETH-BI
Alexander at the Walls of Paradise in the Alexanderlied: Source Usage and Judaic Echoes
No full textThis contribution provides a source usage analysis of two parallel episodes in the S and B redactions of the "Alexanderlied". Both redactions deal with the story of Alexander's visit to Paradise in a slightly different way, and the aim of this paper is to clarify the function of the story both within the texts and within their manuscript contexts
Pathological glial reactions in neurodegenerative disorders: Prospects for future therapeutics
No full textPathological activation of the immune-competent glial cells is an obligatory event in neurodegenerative diseases. The secondary recruitment of astrocytes, resulting from an upgraded microglial activation, represents a critical point. Reactive astrocytes have to give up physiologically important functions (control of extracellular homeostasis and of synaptic transmission) and build a synergistic alliance with microglia in promoting oxidative, excitotoxic and β-amyloid-induced neuronal damage. Growing understanding of the pathogenically relevant molecular signaling pathways opens new possibilities of pharmacological corrections at the second messenger level. Here, the respective know-how of endogenous modulators, such as adenosine, might be used. The aim should be a titration of the glia reaction in order to maintain supposed beneficial functions of reactive microglia and to prevent the dangerous involvement of astrocytes
INDAGINE SU ARTROPODI E ALTRI INVERTEBRATI IN AMBIENTI DUNOSI COSTIERI RECENTEMENTE RESTAURATI: RISULTATI PRELIMINARI
No full text176
Sessione V - Ecologia ed etologia. Presentazioni Posters
INDAGINE SU ARTROPODI E ALTRI INVERTEBRATI IN AMBIENTI
DUNOSI COSTIERI Recente MENTE RESTAURATI: RISULTATI
PRELIMINARI
S. Francati, L. Ferroni, M. Speranza & M. L. Dindo
DiSTA, Università di Bologna, Viale Fanin 42-44, 40127 Bologna
E-mail: [email protected]
Nell’ambito di un progetto di riqualificazione del litorale, riguardante l’area
protetta di Foce del Torrente Bevano (Ravenna), stazione del Parco Regionale
del Delta del Po, è stata realizzata la copertura vegetale di una duna costruita
artificialmente, a seguito dei lavori effettuati nell’inverno 2005/2006 per il riposizionamento
della foce del torrente stesso. Per l’intervento sono state utilizzate
due specie, l’una delle dune embrionali (Agropyron junceum (L.) Beauv.), l’altra
delle dune mobili (Ammophila littoralis (Beauv.) Rothm.). La piantumazione,
effettuata a fine ottobre 2006, ha dato luogo, già nella stagione vegetativa
2007, ad una copertura vegetale di discreto sviluppo, aumentata ulteriormente
negli anni successivi. A primavera 2010 si è verificato l’avvenuto insediamento
spontaneo di invertebrati nel nuovo ambiente, mediante il censimento
di artropodi e di altri gruppi. Tale censimento è stato effettuato anche in una
duna limitrofa, immediatamente a Sud della foce del torrente. Ciò allo scopo
di eseguire un confronto tra la giovane duna e una duna di origine naturale,
dove la copertura vegetale presentava la complessità strutturale e floristica
propria di un sistema dunoso maturo. La principale tecnica di campionamento
utilizzata è stata quella delle trappole a caduta, posizionate a distanza regolare
all’interno dell’area vegetata delle dune, parallelamente alla linea di costa.
Sono state utilizzate anche le tecniche di raccolta manuale e sfalcio con retino.
Dal punto di vista della composizione faunistica, sia nella duna naturale (N) che
in quella ricostituita (R) sono stati rinvenuti i seguenti taxa: Isopoda (N=256;
R=7), Araneae (N=38; R=5), Acari (N=356; R=246), Orthoptera (N=1; R=11),
Neuroptera Myrmeleontidae (N=9; R=15), Diptera (N=1.894; R=1.343), Hemiptera
(N=12; R=8), Coleoptera (Carabidae (N=371; R=134), Staphylinidae (N=1-848;
R=302), Scarabaeoidea (N=641; R=654), Hymenoptera (Formicidae Myrmicinae
(N=657; R=266). Nella sola duna naturale sono stati inoltre rinvenuti Gastropoda
(1.218), Pseudoscorpiones (1), Diplopoda Julidae (48), Collembola (70), Blattodea
(5), Coleoptera Curculionidae (8).
Riguardo alla sostenibilità ambientale dell’intervento di restauro effettuato, il
risultato può essere considerato incoraggiante. Dopo un tempo relativamente
breve dall’esecuzione dell’intervento (poco più di 3 anni), è, infatti, già stata rinvenuta
una comunità di artropodi, e altri invertebrati, ben diversificata e numericamente
abbastanza consistente. I dati raccolti potrebbero essere validi anche
per costituire una banca dati da utilizzare per caratterizzazioni di studi analoghi
Opere del Venerable D. Tomaso da Kempis, Canonigo Regolare
No full textSign.: a\p4\s, A-T\p12\s, V\p1\sPort. con grav. xilAntepA il. é un grav. calc. retrato do auto
Preparation and Characterization of Tin Oxide Nanowires on SiC
No full textInterest in nanowires of metal oxide oxides has been exponentially growing in the last years, due to the attracting potential of application in electronic, optical and sensor field. We have focused our attention on the sensing properties of semiconducting nanowires as conductometric and optical gas sensors. Single crystal tin dioxide nanostructures were synthesized to explore and study their capability in form of multi-nanowires sensors. The nanowires of SnO2 have been used to produce a novel gas sensor based on Pt/oxide/SiC structure and operating as Schottky diode. For the first time, a reactive oxide layer in this device has been replaced by SnO2 nanowires. Proposed sensor has maintained the advantageous properties of known SiC- based MOS devices, that can be employed for the monitoring of gases (hydrogen and hydrocarbons) emitted by industrial combustion processes
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