1,240 research outputs found

    Conditions for electron-cyclotron maser emission in the solar corona

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    Context: The Sun is an active source of radio emission ranging from long duration radio bursts associated with solar flares and coronal mass ejections to more complex, short duration radio bursts such as solar S bursts, radio spikes and fibre bursts. While plasma emission is thought to be the dominant emission mechanism for most radio bursts, the electron-cyclotron maser (ECM) mechanism may be responsible for more complex, short-duration bursts as well as fine structures associated with long-duration bursts. Aims: We investigate the conditions for ECM in the solar corona by considering the ratio of the electron plasma frequency ωp to the electron-cyclotron frequency Ωe. The ECM is theoretically possible when ωp/ Ωe< 1. Methods: Two-dimensional electron density, magnetic field, plasma frequency, and electron cyclotron frequency maps of the off-limb corona were created using observations from SDO/AIA and SOHO/LASCO, together with potential field extrapolations of the magnetic field. These maps were then used to calculate ωp/Ωe and AlfvĂ©n velocity maps of the off-limb corona. Results: We found that the condition for ECM emission (ωp/ Ωe40 G and electron densities are >3 × 108 cm-3. In addition, we found comparatively high AlfvĂ©n velocities (>0.02c or >6000 km s-1) at heights <1.07 R⊙ within the active region. Conclusions: This demonstrates that the condition for ECM emission is satisfied within areas of the corona containing large magnetic fields, such as the core of a large active region. Therefore, ECM could be a possible emission mechanism for high-frequency radio and microwave bursts

    Il regime aggravato della responsabilitĂ  degli Stati nel diritto internazionale

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    The adoption by the International Law Commission (ILC) of the Draft articles on Responsibility of States for Internationally Wrongful Acts (2001) marked the end of a codification process lasted nearly fifty years. While the Draft articles as a whole enjoyed a very positive reception by the international community, it was not the same for those articles concerning one of the most controversial issues of the matter, i.e. the identification of a special regime (so-called “aggravated”) of international responsibility, as a consequence of the most serious breaches of international law. This research aims to assess the effectiveness of the aggravated regime of international responsibility contained in the 2001 ILC’s Draft Articles, analyzing the work of the International Law Commission through the opinions of international law scholars’ and the relevant international judicial decisions

    Ureteropelvic Junction Obstruction: Robot-Assisted Pyeloplasty

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    The standard treatment of ureteropelvic junction obstruction (UPJO) is represented by the Anderson-Hynes dismembered pyeloplasty, even if different approaches, both surgical and endoscopic, have been described. Robot-assisted pyeloplasty (RP) is a feasible and safe approach. The indications for the robotic approach remain the same as those for the laparoscopic or open pyeloplasty. Every patient with symptomatic UPJO, or with decreasing renal function in the presence of UPJO, should undergo RP. The transperitoneal, retroperitoneal, and transmesocolic approaches are described focusing on advantages and disadvantages of each approach. Robot-assisted pyeloplasty has excellent success rates for relief of obstruction and very low peri- and post-operative morbidity. The robotic surgical technique maintains the advantages of laparoscopic surgery providing a more precise manipulation and visualization, and a faster learning curve. Comparative studies are reported to confront the different techniques. Secondary minimally invasive pyeloplasty is obviously a more challenging procedure due to the fibrosis and the adhesions formed after the previous surgery. Newer techniques and indications such as the employment of buccal mucosal graft, the single port approach, and indocyanine green injection are described. Tips and tricks to keep in mind during this kind of procedure are listed in order to report our experience in this setting

    Selection of candidate genes controlling veraison time in grapevine through integration of meta-QTL and transcriptomic data

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    Background High temperature during grape berry ripening impairs the quality of fruits and wines. Veraison time, which marks ripening onset, is a key factor for determining climatic conditions during berry ripening. Understanding its genetic control is crucial to successfully breed varieties more adapted to a changing climate. Quantitative trait loci (QTL) studies attempting to elucidate the genetic determinism of developmental stages in grapevine have identified wide genomic regions. Broad scale transcriptomic studies, by identifying sets of genes modulated during berry development and ripening, also highlighted a huge number of putative candidates. Results With the final aim of providing an overview about available information on the genetic control of grapevine veraison time, and prioritizing candidates, we applied a meta-QTL analysis for grapevine phenology-related traits and checked for co-localization of transcriptomic candidates. A consensus genetic map including 3130 markers anchored to the grapevine genome assembly was compiled starting from 39 genetic maps. Two thousand ninety-three QTLs from 47 QTL studies were projected onto the consensus map, providing a comprehensive overview about distribution of available QTLs and revealing extensive co-localization especially across phenology related traits. From 141 phenology related QTLs we generated 4 veraison meta-QTLs located on linkage group (LG) 1 and 2, and 13 additional meta-QTLs connected to the veraison time genetic control, among which the most relevant were located on LG 14, 16 and 18. Functional candidates in these intervals were inspected. Lastly, taking advantage of available transcriptomic datasets, expression data along berry development were integrated, in order to pinpoint among positional candidates, those differentially expressed across the veraison transition. Conclusion Integration of meta-QTLs analysis on available phenology related QTLs and data from transcriptomic dataset allowed to strongly reduce the number of candidate genes for the genetic control of the veraison transition, prioritizing a list of 272 genes, among which 78 involved in regulation of gene expression, signal transduction or development

    Concepts and Methods to Assess the Dynamic Thermal Rating of Underground Power Cables

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    With the increase in the electrical load and the progressive introduction of power generation from intermittent renewable energy sources, the power line operating conditions are approaching the thermal limits. The definition of thermal limits variable in time has been addressed under the concept of dynamic thermal rating (DTR), with which it is possible to provide a more detailed assessment of the line rating and exploit the electrical system more flexibly. Most of the literature on DTR has addressed overhead lines exposed to different weather conditions. The interest in the dynamic thermal rating of power cables is increasing, considering the evolution of computational methods and advanced systems for cable monitoring. This paper contains an overview of the concepts and methods referring to dynamic cable rating (DCR). Starting from the analytical formulations developed many years ago for determining the power cable rating in steady-state conditions, also reported in International Standards, this paper considers the improvements of these formulations proposed during the years. These improvements are leading to include more specific details in the models used for DCR analysis and the computational methods used to assess the power cable’s thermal conditions buried in soil. This paper is focused on highlighting the path from the initial theories and models to the latest literature contributions. Attention is paid to thermal modelling with different levels of detail, applications of 2D and 3D solvers and simplified models, and their validation based on experimental measurements. A salient point of the overview is considering the DCR impact on reliability aspects, risk estimation, real-time calculations, forecasting, and planning with different time horizons

    VALE-Emotions: Teaching mobile application for individuals with Autism Spectrum Disorders

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    In this paper, the development of an interactive mobile application to strengthen the learning of emotion recognition in children with Autism Spectrum Disorders (ASD) is presented. This App is part of an authoring Virtual Advanced Learning Environment (VALE) devoted to support teaching and learning activities. VALE-Emotions App is based on the six basic emotions studied by (Paul Ekman, 1992), but it is not only limited to the recognition of such emotions in their highest intensity levels. In fact, the app allows for determining the effective recognition of these emotions at different intensity levels. Such intensity levels are generated by an authoring Dynamic Facial Expressions (DFE) coding using virtual avatars. Each learning activity is carried out through training and tests applications, giving to the users the opportunity of freely developing, learning, and strengthen social skills in an entertaining way. The results of the experimentation of the VALE-Emotions on subjects with ASD are also reported. In general, the participants showed efficient response at the stimulus during the developed activities obtaining a high and fast recognition of certain emotions

    Characteristics and coastal effects of a destructive marine storm in the Gulf of Naples (southern Italy)

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    Destructive marine storms bring large waves and unusually high surges of water to coastal areas, resulting in significant damages and economic loss. This study analyses the characteristics of a destructive marine storm on the strongly inhabited coastal area of Gulf of Naples, along the Italian coasts of the Tyrrhenian Sea. This is highly vulnerable to marine storms due to the accelerated relative sea level rise trend and the increased anthropogenic impact on the coastal area. The marine storm, which occurred on 28 December 2020, was analyzed through an unstructured wind-wave coupled model that takes into account the main marine weather components of the coastal setup. The model, validated with in situ data, allowed the establishment of threshold values for the most significant marine and atmospheric parameters (i.e., wind intensity and duration) beyond which an event can produce destructive effects. Finally, a first assessment of the return period of this event was evaluated using local press reports on damage to urban furniture and port infrastructures

    Subcellular elements responsive to the biomechanical activity of triple-negative breast cancer-derived small extracellular vesicles

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    Abstract Triple-negative breast cancer (TNBC) stands out for its aggressive, fast spread, and highly metastatic behavior and for being unresponsive to the classical hormonal therapy. It is considered a disease with a poor prognosis and limited treatment options. Among the mechanisms that contribute to TNBC spreading, attention has been recently paid to small extracellular vesicles (sEVs), nano-sized vesicles that by transferring bioactive molecules to recipient cells play a crucial role in the intercellular communication among cancer, healthy cells, and tumor microenvironment. In particular, TNBC-derived sEVs have been shown to alter proliferation, metastasis, drug resistance, and biomechanical properties of target cells. To shed light on the molecular mechanisms involved in sEVs mediation of cell biomechanics, we investigated the effects of sEVs on the main subcellular players, i.e., cell membrane, cytoskeleton, and nuclear chromatin organization. Our results unveiled that TNBC-derived sEVs are able to promote the formation and elongation of cellular protrusions, soften the cell body, and induce chromatin decondensation in recipient cells. In particular, our data suggest that chromatin decondensation is the main cause of the global cell softening. The present study added new details and unveiled a novel mechanism of activity of the TNBC-derived sEVs, providing information for the efficient translation of sEVs to cancer theranostics

    Oxidative stress and inflammation induced by environmental and psychological stressors: a biomarker perspective

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    Significance. The environment can elicit biological responses such as oxidative stress (OS) and inflammation as consequence of chemical, physical or psychological changes. As population studies are essential for establishing these environment-organism interactions, biomarkers of oxidative stress or inflammation are critical in formulating mechanistic hypotheses. Recent advances. By using examples of stress induced by various mechanisms, we focus on the biomarkers that have been used to assess oxidative stress and inflammation in these conditions. We discuss the difference between biomarkers that are the result of a chemical reaction (such as lipid peroxides or oxidized proteins that are a result of the reaction of molecules with reactive oxygen species, ROS) and those that represent the biological response to stress, such as the transcription factor NRF2 or inflammation and inflammatory cytokines. Critical issues. The high-throughput and holistic approaches to biomarker discovery used extensively in large-scale molecular epidemiological exposome are also discussed in the context of human exposure to environmental stressors. Future directions. We propose to consider the role of biomarkers as signs and distinguish between signs that are just indicators of biological processes and proxies that one can interact with and modify the disease process

    Influence of superabsorbent polymers on hydration of cement pastes with low water-to-binder ratio: A calorimetry study

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    Internal curing with superabsorbent polymers (SAP) is a method for promoting hydration of cement and limiting self-desiccation, shrinkage and cracking in high-performance, and ultra high-performance concrete with low water-to-binder ratio. SAP are introduced in the dry state during mixing and form water-filled inclusions by absorbing pore solution. The absorbed solution is later released to the cement paste during hydration of the cement. In this paper, cement pastes with low water-to-binder ratios incorporating superplasticizer and different dosages of SAP and corresponding additional water were prepared. Reference cement pastes without SAP but with the same amount of water and superplasticizer were also mixed. Isothermal calorimetry was used to measure hydration heat flow. Water entrainment by means of SAP increased the degree of hydration at later hydration times in a manner similar to increasing the water-to-binder ratio. Addition of SAP also delayed the main calorimetric hydration peak compared to the reference pastes, however, in a less prominent manner than the increase in water-to-cement ratio
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