99 research outputs found
Analytic Smoothing and Nekhoroshev Estimates for Holder Steep Hamiltonians
In this paper we prove the first result of Nekhoroshev stability for steep Hamiltonians in Holder class. Our newapproach combines the classical theory of normal forms in analytic category with an improved smoothing procedure to approximate an Holder Hamiltonian with an analytic one. It is only for the sake of clarity that we consider the (difficult) case of Holder perturbations of an analytic integrable Hamiltonian, but our method is flexible enough to work in many other functional classes, including the Gevrey one. The stability exponents can be taken to be (l - 1)/(2n alpha(1)...alpha(n-2)) + 1/2 for the time of stability and 1/(2n alpha(1)...alpha(n-1)) for the radius of stability, n being the dimension, l > n + 1 being the regularity and the ai 's being the indices of steepness. Crucial to obtain the exponents above is a new non-standard estimate on the Fourier norm of the smoothed function. As a byproduct we improve the stability exponents in the C-k class, with integer k
Unmanned Aerial Vehicles for Debris Survey in Coastal Areas: Long-Term Monitoring Programme to Study Spatial and Temporal Accumulation of the Dynamics of Beached Marine Litter
Unmanned aerial vehicles (UAVs) are becoming increasingly accessible tools with widespread use as environmental monitoring systems. They can be used for anthropogenic marine debris survey, a recently growing research field. In fact, while the increasing efforts for offshore investigations lead to a considerable collection of data on this type of pollution in the open sea, there is still little knowledge of the materials deposited along the coasts and the mechanism that leads to their accumulation pattern. UAVs can be effective in bridging this gap by increasing the amount of data acquired to study coastal deposits, while also limiting the anthropogenic impact in protected areas. In this study, UAVs have been used to acquire geo-referenced RGB images in a selected zone of a protected marine area (the Migliarino, Massacciuccoli, and San Rossore park near Pisa, Italy), during a long-term (ten months) monitoring programme. A post processing system based on visual interpretation of the images allows the localization and identification of the anthropogenic marine debris within the scanned area, and the estimation of their spatial and temporal distribution in different zones of the beach. These results provide an opportunity to investigate the dynamics of accumulation over time, suggesting that our approach might be appropriate for monitoring and collecting such data in isolated, and especially in protected, areas with significant benefits for different types of stakeholders
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Inhibition of de novo ceramide biosynthesis affects aging phenotype in an in vitro model of neuronal senescence.
Although aging is considered to be an unavoidable event, recent experimental evidence suggests that the process can be counteracted. Intracellular calcium (Ca2+i) dyshomeostasis, mitochondrial dysfunction, oxidative stress, and lipid dysregulation are critical factors that contribute to senescence-related processes. Ceramides, a pleiotropic class of sphingolipids, are important mediators of cellular senescence, but their role in neuronal aging is still largely unexplored. In this study, we investigated the effects of L-cycloserine (L-CS), an inhibitor of thede novoceramide biosynthesis, on the aging phenotype of cortical neurons cultured for 22 days, a setting employed as anin vitromodel of senescence. Our findings indicate that, compared to control cultures, 'aged' neurons display dysregulation of [Ca2+]ilevels, mitochondrial dysfunction, increased generation of reactive oxygen species (ROS), altered synaptic activity as well as the activation of neuronal death-related molecules. Treatment with L-CS positively affected the senescent phenotype, a result associated with recovery of neuronal [Ca2+]isignaling and reduction of mitochondrial dysfunction and ROS generation. The results suggest that thede novoceramide biosynthesis represents a critical intermediate in the molecular and functional cascade leading to neuronal senescence and identify ceramide biosynthesis inhibitors as promising pharmacological tools to decrease age-related neuronal dysfunctions
An energy information system for retrofitting smart urban areas
This paper presents the ENERSI platform, an energy information system that provides advanced energy services by means of integrating energy related data from multiple domains and formats using Semantic Web technologies. The platform services can provide qualified information at different scales – from building to district, city and region – to different kind of users – such as building owners, city planner, energy agencies, architects, contractors and consultants – to take decisions aimed at improving the building energy performance in their respective decision-making realms.Peer ReviewedPostprint (published version
Enhancing energy performance certificates with energy related data to support decision making for building retrofitting
The increasing availability of large-scale repositories of energy performance certificates offers the opportunity to interlink them with other data sources (cadastre, geographical data, weather data, building regulations, catalogues of refurbish?ment measures) and to derive innovative services that use the integrated data in conjunction with various tools (energy performance simulation, environmental impact). In the ENERSI project, two applications have been developed to make it easier for building owners and planners to take informed decisions to improve building energy performance in their properties and in their municipalities. These applications, named ENERHAT and ENERPAT, are based on the integration of building data from multiple sources and domains (energy performance certificates, cadastre, geographic information, and census), building refurbishment policies and assessment tools. Data integration has been performed using Semantic Web technologies. A user-friendly interface enables end-users of these on-line applications to obtain information about the current building status of properties, the measures which could be undertaken to improve them, the energy savings achieved and their respective costs.Peer ReviewedPostprint (published version
SEíS: Sistema basado en tecnologías semánticas para integrar la información energética de los edificios
Access to reliable energy related data is a fundamental factor when taking decisions that help to improve the energy efficiency of buildings. The increase in the amount of data we have available has led to the need to develop information systems that facilitate the analysis of such data to the agents which are present throughout the building life cycle, from the design phase to maintenance. Semantic web technologies provide a solution to interlink distributed data sources. This requires the construction of shared vocabularies (i.e. ontologies) which capture the meaning that users give to the data and facilitate access to them. As yet there are no consolidated methods to build these vocabularies. This article presents the methodology developed to create SEíS, an energy information system that uses semantic technologies to integrate energy related data and to facilitate services to the different agents involved throughout the stages of the building life cycle.Objectius de Desenvolupament Sostenible::13 - Acció per al ClimaPostprint (published version
Mapping of Yucca gloriosa invasion along Mediterranean coastal dunes using unmanned aerial vehicles (UAVs)
Invasive Alien Plants (IAPs) are defined as those species whose introduction and/or spread outside their natural distribution can threaten the biological diversity of an ecosystem. They represent a severe threat to biodiversity and can severely alter the performance of crucial ecosystems such as coastal dunes. Coastal dunes are composed of specialized fauna and flora, converting them into strategic ecosystems due to their unique ecological functions.
Coastal dunes are one of the most invaded European environments, with a total flora composed of up to 7% of IAPs. One of these IAPs is Yucca gloriosa L. (Asparagaceae), a homoploid hybrid native plant from the United States of America introduced to Europe for ornamental purposes. For Italy, Y. gloriosa is a typical invasive species related to fixed dunes dominated by Juniperus sp. pl. (with which it competes).
Concerning biological invasions, maybe the most effective management strategy is early detection and mapping. In that sense, this work explores and tests the potential of unmanned aerial vehicles (UAVs) for detecting, mapping, and managing the Y. gloriosa invasion along the Mediterranean coastal dunes of a protected area located in Tuscany (Italy).
In detail, this work focuses on four aspects: i) determine the suitability of RGB images to map Y. gloriosa, ii) identify the best time of data acquisition, iii) detect changes affecting the occurrence and cover of Y. gloriosa, and iv) propose a set of management actions to preserve a coastal dune ecosystem subjected to plant invasion.
The UAV images allowed the generation of ultra-high spatial resolution maps to assess the Y. gloriosa invasion and distribution along the surveyed sandy dunes. The morphological characteristics of this plant – especially at the foliar level – make the invasion of Y. gloriosa particularly suitable for being evaluated and managed using UAV mapping, especially in coastal dunes vegetation that can be a mosaic of different plant communities hard to identify when airborne or satellite images are used.
According to the obtained results, the spring season is the perfect time to collect data because light conditions are ideal, with minimal shading effects. Also, due to the peculiar morphology of Y. gloriosa leaves, the timing of data collection seems not crucial for mapping this IAP on coastal dune habitats.
Despite the massive eradication action funded by a LIFE project during the period 2005-2009, Y. gloriosa is still present in the protected area and affects the priority habitat of juniper. This might be linked to the fact that Y. gloriosa is a perennial rhizomatous shrub capable of switching its photosynthesis from the C3 to CAM pathway and, therefore, withstand the harsh environmental conditions of dune ecosystems.
The early detection using UAVs is the first line of defense against IAPs colonization over any ecosystem. From a conservation and management point of view, this work suggests the development of annual biomonitoring of Y. gloriosa to check its distribution over time and control its spread where it becomes particularly invasive. In this case, one possible strategy will be to keep the IAP in isolated nuclei of plants that are easier to remove with mechanical methods. In a broader view, the study area and the Mediterranean coast must include the ban on introducing non-native species as a strategy, adopting a short-term non-native Management Plan as urgent action
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The pharmacological perturbation of brain zinc impairs BDNF-related signaling and the cognitive performances of young mice.
Zinc (Zn2+) is a pleiotropic modulator of the neuronal and brain activity. The disruption of intraneuronal Zn2+ levels triggers neurotoxic processes and affects neuronal functioning. In this study, we investigated how the pharmacological modulation of brain Zn2+ affects synaptic plasticity and cognition in wild-type mice. To manipulate brain Zn2+ levels, we employed the Zn2+ (and copper) chelator 5-chloro-7-iodo-8-hydroxyquinoline (clioquinol, CQ). CQ was administered for two weeks to 2.5-month-old (m.o.) mice, and effects studied on BDNF-related signaling, metalloproteinase activity as well as learning and memory performances. CQ treatment was found to negatively affect short- and long-term memory performances. The CQ-driven perturbation of brain Zn2+ was found to reduce levels of BDNF, synaptic plasticity-related proteins and dendritic spine density in vivo. Our study highlights the importance of choosing "when", "where", and "how much" in the modulation of brain Zn2+ levels. Our findings confirm the importance of targeting Zn2+ as a therapeutic approach against neurodegenerative conditions but, at the same time, underscore the potential drawbacks of reducing brain Zn2+ availability upon the early stages of development
Response to Seasonal Changes in Blood Pressure: Possible Interaction Between Sunlight and Brain Serotonin
Primary retroperitoneal abscesses due to Rhodococcus equi in a patient with severe nephrotic syndrome: successful antibiotic treatment with linezolid and tigecycline.
Abstract We present a case of Rhodococcus equi primary retroperitoneal abscesses without pulmonary involvement in an immunocompromised patient with severe nephrotic syndrome. No risk factors for exposure to R. equi were present. The infection was successfully treated with long-term combination antibiotic treatment including linezolid and tigecycline
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