101,938 research outputs found
Growth rate of alkali feldspars in decompression-induced crystallization experiments in a trachytic melt of the Phlegraean Fields (Napoli, Italy)
No full textAbstract: We have performed decompression experiments on a Monte Nuovo trachytic composition, at pressure between 30 and 200 MPa, temperature between 750 C and 850 C, time between 7200 and 50,400 (200) seconds and fO21⁄4 NNOþ 0.8 from which the growth rate of alkali feldspar in trachytic melts were obtained. The crystal growth rate (G) varies from 1.39108 to 1.65107 cm/s and is higher in experiments with shorter duration (7200 s), while it tends to decrease with increasing duration (21,600 and 50,400 s).
The values of G presented here are similar (108 cm/s) or higher by almost an order of magnitude (107 cm/s) when compared with the growth rates obtained from an earlier study of Monte Nuovo eruptive dynamics. Therefore, the magma ascent times calculated are
similar (1–2 days) or slightly lower (several hours) relative to those estimated in that study.
Key-words: crystallization kinetics, decompression, trachytic melt, alkali feldspars, Phlegraean Fields
Microscale textural heterogeneity and tip-streaming instability in alkaline magmas: evidence in tube pumices from Campi Flegrei, Italy
No full textWe present a textural investigation of compositionally homogeneous alkaline tube pumices from the plinian fallouts of the Agnano Monte Spina eruption (ca. 4.1 ka), Campi Flegrei, Italy. The pumice clasts present strong textural complexity from hand specimen to microscopic scale of inspection. The clasts are characterized by large vesicle tubes that extend up to several millimetres along the clast main axis. They also exhibit small and elongated vesicles arranged in stretched bands around textural domains of larger, sub-spherical vesicles associated with pyroxene, feldspar, and biotite phenocrysts. Clasts, vesicle tubes, vesicle deformation, major axes of pyroxene phenocrysts and crystals with size ≤100 μm align in the same direction. In addition, we observe chains of gradually smaller stretched vesicles likely generated from break-up of a larger parent vesicle (i.e., tip-streaming phenomenon). We use image analysis to quantify the heterogeneity of vesicle sizes and shapes. Then, we deduce the Capillary number (Ca) of the each single vesicle, which represents the ratio between the deforming viscous stress on a bubble and the restoring stress supplied by surface tension, and obtain the spatial distribution of Ca values within pumice clasts. As Ca depends on strain-rate and viscosity, the spatial distribution of Ca values provides us with a snapshot of the sub-millimetre scale variation in magma strain-rate and rheology before fragmentation. Ca in highly stretched vesicles is close to values (0.45 to 0.6) required for bubble-breakup induced by tip-streaming. Instead, low Ca values (0.3 to 0.45) are calculated for large sub-spherical vesicles mostly distributed around phenocrysts. We suggest that sub-millimetre heterogeneities in vesicle sizes and shapes recorded in tube pumices are caused by a combination of tip-streaming, heterogeneous bubble nucleation and second-boiling processes prior to fragmentation. The heterogeneous spatial distribution of Ca values may be the result of local micrometric shear localisation and consequent deformation upon break-up experienced by magma while ascending in the conduit. This deformation suggests that a variation of magma strain-rate and viscosity occurred before fragmentation at the clast microscale and this is likely to affect magma dynamics and fragmentation. Our results claim for future experimental and numerical modelling studies that investigate and consider the effect of such micrometric heterogeneities on magma rheology and flow condition variations inside volcanic conduits
Exploring the Possible Use of AI Chatbots in Public Health Education: Feasibility Study
No full textBackground: Artificial intelligence (AI) is a rapidly developing field with the potential to transform various aspects of health care and public health, including medical training. During the “Hygiene and Public Health” course for fifth-year medical students, a practical training session was conducted on vaccination using AI chatbots as an educational supportive tool. Before receiving specific training on vaccination, the students were given a web-based test extracted from the Italian National Medical Residency Test. After completing the test, a critical correction of each question was performed assisted by AI chatbots. Objective: The main aim of this study was to identify whether AI chatbots can be considered educational support tools for training in public health. The secondary objective was to assess the performance of different AI chatbots on complex multiple-choice medical questions in the Italian language. Methods: A test composed of 15 multiple-choice questions on vaccination was extracted from the Italian National Medical Residency Test using targeted keywords and administered to medical students via Google Forms and to different AI chatbot models (Bing Chat, ChatGPT, Chatsonic, Google Bard, and YouChat). The correction of the test was conducted in the classroom, focusing on the critical evaluation of the explanations provided by the chatbot. A Mann-Whitney U test was conducted to compare the performances of medical students and AI chatbots. Student feedback was collected anonymously at the end of the training experience. Results: In total, 36 medical students and 5 AI chatbot models completed the test. The students achieved an average score of 8.22 (SD 2.65) out of 15, while the AI chatbots scored an average of 12.22 (SD 2.77). The results indicated a statistically significant difference in performance between the 2 groups (U=49.5, P<.001), with a large effect size (r=0.69). When divided by question type (direct, scenario-based, and negative), significant differences were observed in direct (P<.001) and scenario-based (P<.001) questions, but not in negative questions (P=.48). The students reported a high level of satisfaction (7.9/10) with the educational experience, expressing a strong desire to repeat the experience (7.6/10). Conclusions: This study demonstrated the efficacy of AI chatbots in answering complex medical questions related to vaccination and providing valuable educational support. Their performance significantly surpassed that of medical students in direct and scenario-based questions. The responsible and critical use of AI chatbots can enhance medical education, making it an essential aspect to integrate into the educational system
Microwave irradiation for airborne virus inactivation: Evidence and future perspectives
No full textNon-thermal microwave (MW) irradiation has emerged as a promising approach for inactivating airborne viruses by exploiting their vibrational properties through selective resonant energy transfer (SRET). In this narrative review, we synthesize current evidence on the antiviral efficacy of non-thermal microwave (MW) technologies, evaluate their feasibility for indoor infection control, and highlight existing limitations as well as future research directions. A literature search was conducted across PubMed, Scopus, Google Scholar, and ScienceDirect for studies published between January 1, 2015, and March 7, 2025, using keywords related to MW irradiation, SRET, and airborne viruses. The evidence was organized into three key themes: mechanistic foundations of the technology, effectiveness against airborne viruses, and regulatory and safety considerations. The available data indicate that MW irradiation disrupts viral structures through vibrational resonance mechanisms, with effectiveness varying by viral type and depending on optimized frequency and exposure duration. Regulatory authorities recently acknowledged its potential to reduce airborne transmission, contingent on meeting stringent safety standards for electromagnetic compatibility, specific absorption rates, and power density. In summary, non-thermal MW irradiation offers a scalable solution for reducing airborne respiratory virus transmission. Pending further real-world validation, integrating this technology into public health strategies offers a promising approach to strengthen infection prevention and control in both healthcare settings and indoor environments, effectively targeting both human and zoonotic infections
Use of Digital Devices to Assess Vaccine Hesitancy and Promote Pertussis Vaccination Among Pregnant Women
No full textThe pertussis vaccination in pregnancy represents the main preventive strategy against this disease in the first trimester of life. The purpose of the study is to develop an e-health tool for assessing vaccination attitudes and to evaluate three types of communication for pregnant women, providing efficient information for their vaccination choice. One-hundred-and-five participants were assessed using a psychometric questionnaire implemented on a tablet and subsequently, they were exposed to different communication formats based on the Elaboration Likelihood Model (ELM). The participants in each group receive the same information contents on vaccination and pertussis in a different format (two provided by digital devices and one by leaflet). The difference between the post-intervention scores on vaccination intention showed that a video containing an expert-patient conversation was equivalent to the information provided by a collaborator delivering the leaflet and these two formats were significantly more efficient compared to the information provided through interactive infographics. These results demonstrate the importance of interpersonal exchange as a key factor also in the e-health tool to provide persuasive health information
Microalbuminuria and renal haemodynamics in essential hypertension.
No full textThe present study was designed to evaluate the renal haemodynamic pattern of never-treated microalbuminuric and normoalbuminuric patients with essential hypertension. A total of 19 never-treated essential hypertensive patients with microalbuminuria were selected and, as control subjects, 24 never-treated essential hypertensive patients without microalbuminuria (determined on three 24-h urine collections) were recruited. In the two groups, we compared blood pressure values, standing plasma noradrenaline, plasma renin activity, plasma aldosterone, urinary aldosterone, lipid profile, serum glucose and uric acid, glomerular filtration rate and renal plasma flow. In comparison with normoalbuminuric patients, microalbuminuric patients showed significantly higher systolic blood pressure values (P < 0.05), higher renal vascular resistances (P < 0.05) and lower plasma renin activity values (P < 0.01). Urinary albumin excretion showed a significant positive correlation with systolic (r = 0.46, P < 0.005) and mean blood pressure (r = 0.38, P < 0.05), serum uric acid (r = 0.43, P < 0.005) and triglyceride values (r = 0.36, P < 0.005), and a significant negative correlation with plasma renin activity (r = -0.34, P < 0.05). The present data are consistent with the occurrence of renal vasoconstriction in microalbuminuric never-treated essential hypertensive patients
Bibliographie Hilarion G. Petzold 1958 – 2009 mit Anhang als Einführung
No full textDieses Archiv enthält die Gesamtbibliographie der Werke des Autors nebst einiger Texte „Über H. G. Petzold“ im Schlussteil der Bibliographie sowie einen Anhang mit einer Einführung in die Architektur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author and some texts about H. G. Petzold, moreover an epilogue with an introduction to the architecture of the works in its epistemological structure and composition and as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2009-petzold-h-g-gesamtbibliographie-h-g-petzold-1958-2009-updating-november2009/peerReviewedpublishedVersio
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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