169 research outputs found

    Unlocking Past Ocean Circulation And Climate Changes Using Benthic Foraminifera

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    The analysis of the chemical and isotopic composition of calcareous benthic foraminifera is a widely used approach to reconstruct changes in ocean circulation and climate through time. In the first part of the seminar, I will present the application of the “traditional” benthic foraminiferal oxygen and carbon isotope ratios to reconstruct ocean circulation changes in the North Atlantic during the greenhouse-icehouse transition, one of the most important climatic and oceanographic transitions of the last 50 million years. In addition, I will present microscopy and spectroscopy data revealing a novel biomineralization strategy in a particular foraminiferal species called Melonis barleeanus. In the second part of the talk, I will show some preliminary data regarding the development of novel approaches to study methane dynamics and biogeochemical cycles in marine sediments today and in the geological past. In particular, the “non- traditional” benthic foraminiferal hydrogen and sulphur isotope ratios look very promising for studying methane fluxes in marine sediments, whereas the investigation of the benthic foraminiferal S/Ca, Mn/Ca, and Fe/Ca can provide some insight on modern and past changes of the carbon, sulfur, manganese, and iron cycles as consequence of methane release, methane oxidation, and availability of dissolved oxygen in sediments

    Witnessing entanglement in hybrid systems

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    We extend the definition of entanglement witnesses based on structure factors to the case in which the position of the scatterers is quantized. This allows us to study entanglement detection in hybrid systems. We provide several examples that show how these extra degrees of freedom affect the detection of entanglement by directly contributing to the measurement statistics. We specialize the proposed witness operators for a chain of trapped ions. Within this framework, we show how the collective vibronic state of the chain can act as an undesired quantum environment and how ions quantum motion can affect the entanglement detection. Finally, we investigate some specific cases where the method proposed leads to detection of hybrid entanglement.Comment: 6 pages, 4 figure

    Biogeochemical investigations of methane seepage at the ultraslow-spreading Arctic mid-ocean ridge: Svyatogor ridge, Fram Strait

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    The Arctic continental shelves are important reservoirs of methane stored in gas hydrates and deeper geological formations. However, little is known about methane dynamics in deeper oceanic settings such as mid-ocean ridges, mainly due to operational challenges related to their remoteness. This study investigates a recently discovered methane seepage environment at Svyatogor Ridge, a sediment-covered transform fault on the western flank of the Arctic mid-ocean ridge west of Svalbard. Svyatogor Ridge was previously hypothesized to host deep gas hydrates and active fluid flow systems, which is a unique combination for this setting and requires geochemical evidence. Based on sediment and foraminiferal geochemistry, we demonstrate that Svyatogor Ridge hosts a shallow methane cycle with anaerobic oxidation of microbial methane, sustaining chemosynthetic communities at the seafloor. Our geochemical datasets also suggest that methane fluxes were higher in the past than today and long-lasting, with episodes of intense methane oxidation recorded in pre-Holocene sediments. Methane seepage is still ongoing at this location, although no evidence exists that methane is reaching the sea surface. The results provide the first evidence of a methane seepage environment ever reported from the ultra-slow spreading Arctic mid-ocean ridge, thus calling for a reevaluation of the role of this type of ridge in the ocean methane cycle

    Lo stato dell’arte dei progetti nature-based in ambito educativo, formativo, terapeutico e ricreativo in Italia: quadro concettuale e una possibile categorizzazione dei settori/contesti

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    National and international literature on nature-based programs in the educational,training, therapeutic and leisure areas reveals a lack of homogeneityin using the different terminologies: the various terms are used with differentmeanings, both by practitioners and by scholars. The present work is theconceptual premise of a research which outlined a quantitative and qualitativemapping of the Italian organizations that use nature-based approachesand methodologies. This paper provides both a literature review of the theoreticalroots which support nature-based experiences, and a reconnaissanceof the national situation regarding the use of terminology and thedifferentiation in the various specific practical fields. In order to properly introducethe mapping research, this work proposes a conceptual organizationdefining four macro-areas of the nature-based sector. This categorization,which is organized around some indicators, aims to be flexible and to havepermeable borders; and it has the goal to help orienting in the complexframework of the numerous nature-based proposals in Italy.Dall’analisi della letteratura nazionale e internazionale sulle pratiche naturebasedin ambito educativo, formativo, terapeutico e ricreativo, emerge disomogeneitànell’utilizzo delle diverse terminologie, utilizzate con significatitalvolta molto diversi sia dagli stessi soggetti che se ne occupano, sia daglistudiosi che ne teorizzano e concettualizzano le pratiche. Il presente contributoù la premessa concettuale di una ricerca* effettuata per disegnare unamappa quantitativa e qualitativa delle realtà che operano in Italia utilizzandometodologie e approcci nature-based e propone sia una rassegna delle radiciteoriche che sostengono le esperienze nature-based, sia una ricostruzionedel panorama nazionale in merito all’utilizzo della terminologia e alla differenziazionenei diversi ambiti specifici di operatività. Ai fini della suddetta rilevazione,inoltre, il lavoro propone un’organizzazione concettuale chedelinea quattro macro-aree del settore nature-based; la categorizzazione proposta,organizzata intorno ad alcuni indicatori, intende essere fluida e daiconfini permeabili ed ù finalizzata a facilitare l’orientamento nel complessoquadro delle numerose proposte nature-based presenti sul territorio italiano

    Between Participatory Approaches and Politics, Promoting Social Innovation in Smart Cities: Building a Hum–Animal Smart City in Lucca

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    In recent decades, the interest in social innovation and nature-based solutions has spread in scientific articles, and they are increasingly deployed for cities’ strategic planning. In this scenario, participatory approaches become pivotal to engaging the population and stakeholders in the decision- making process. In this paper, we reflect on the first year’s results and the strengths and weaknesses— of the participatory activities realized in Lucca to co-design and co-deploy a smart city based on human–animal relationships in the framework of the European project Horizon 2020 (IN-HABIT). Human–animal bonds, as nature-based solutions, are scientifically and practically underestimated. Data were collected on the activities organized to implement a public–private–people partnership in co-designing infrastructural solutions (so-called Animal Lines) and soft nature-based solutions to be implemented in the city. Stakeholders actively engaged in mutual discussions with great enthusiasm, and the emergent ideas (the need to improve people’s knowledge of animals and develop a map showing pet-friendly services and places and the need for integration to create innovative pet services) were copious and different while showing many connections among the various points of view. At the same time, a deeper reflection on the relationships among the participatory activities and institutionally integrated arrangements also emerged

    Physiological indicators of acute and chronic stress in securely and insecurely attached dogs undergoing a strange situation procedure (SSP): Preliminary results

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    The quality of the attachment bond towards the caregiver may affect the dog’s physiological responses to stressful stimuli. This study aimed to measure chronic and acute physiological parameters of stress in ten securely and ten insecurely attached dogs. The twenty experimental subjects were selected from a sample of dogs that participated with their owners in the Strange Situation Procedure. Saliva samples were collected before (T0) and after (T1) the test. Blood pressure, heart rate, respiratory rate, and rectal temperature were measured after the test, only. At this time, a hair sample was also collected. RM ANOVA was used to analyse cortisol concentrations between secure and insecure dogs at T0 and T1. Mann–Whitney U test or T test were used for other physiological parameters. Insecure dogs had significant higher salivary cortisol concentrations than secure dogs at T1 (p = 0.024), but only a non-significant trend towards higher cortisol concentrations at T0 (p = 0.099). Post-test heart rate also tended to be higher in insecure compared to secure dogs (p = 0.077). No significant differences in hair cortisol concentration were found. The quality of attachment may affect the dog’s physiological response to acute stress, at least when related to separation from the caregiver. The effect of attachment on chronic stress requires further investigation

    Macular Microcysts in Mitochondrial Optic Neuropathies: Prevalence and Retinal Layer Thickness Measurements.

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    PurposeTo investigate the thickness of the retinal layers and to assess the prevalence of macular microcysts (MM) in the inner nuclear layer (INL) of patients with mitochondrial optic neuropathies (MON).MethodsAll patients with molecularly confirmed MON, i.e. Leber's Hereditary Optic Neuropathy (LHON) and Dominant Optic Atrophy (DOA), referred between 2010 and 2012 were enrolled. Eight patients with MM were compared with two control groups: MON patients without MM matched by age, peripapillary retinal nerve fiber layer (RNFL) thickness, and visual acuity, as well as age-matched controls. Retinal segmentation was performed using specific Optical coherence tomography (OCT) software (Carl Zeiss Meditec). Macular segmentation thickness values of the three groups were compared by one-way analysis of variance with Bonferroni post hoc corrections.ResultsMM were identified in 5/90 (5.6%) patients with LHON and 3/58 (5.2%) with DOA. The INL was thicker in patients with MON compared to controls regardless of the presence of MM [133.1±7Όm vs 122.3±9Όm in MM patients (p<0.01) and 128.5±8Όm vs. 122.3±9Όm in no-MM patients (p<0.05)], however the outer nuclear layer (ONL) was thicker in patients with MM (101.4±1mΌ) compared to patients without MM [77.5±8mΌ (p<0.001)] and controls [78.4±7mΌ (p<0.001)]. ONL thickness did not significantly differ between patients without MM and controls.ConclusionThe prevalence of MM in MON is low (5-6%), but associated with ONL thickening. We speculate that in MON patients with MM, vitreo-retinal traction contributes to the thickening of ONL as well as to the production of cystic spaces

    Nonequilibrium quantum thermodynamics in Coulomb crystals

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    We present an in-depth study of the nonequilibrium statistics of the irreversible work produced during sudden quenches in proximity to the structural linear-zigzag transition of ion Coulomb crystals in 1+1 dimensions. By employing both an analytical approach based on a harmonic expansion and numerical simulations, we show the divergence of the average irreversible work in proximity to the transition. We show that the nonanalytic behavior of the work fluctuations can be characterized in terms of the critical exponents of the quantum Ising chain. Due to the technological advancements in trapped-ion experiments, our results can be readily verified
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