1,956 research outputs found
Non-equilibrium ionization around clouds evaporating in the interstellar medium
It is of prime importance for global models of the interstellar medium to know whether dense clouds do or do not evaporate in the hot coronal gas. The rate of mass exchanges between phases depends very much on that. McKee and Ostriker's model, for instance, assumes that evaporation is important enough to control the expansion of supernova remnants, and that mass loss obeys the law derived by Cowie and McKee. In fact, the geometry of the magnetic field is nearly unknown, and it might totally inhibit evaporation, if the clouds are not regularly connected to the hot gas. Up to now, the only test of the theory is the U.V. observation (by the Copernicus and IUE satellites) of absorption lines of ions such as OVI or NV, that exist at temperatures of a few 100,000 K typical of transition layers around evaporating clouds. Other means of testing the theory are discussed
Can be gravitational waves markers for an extra-dimension?
The main issue of the present letter is to fix specific features (which turn
out being independent of extradimension size) of gravitational waves generated
before a dimensional compactification process. Valuable is the possibility to
detect our prediction from gravitational wave experiment without high energy
laboratory investigation. In particular we show how gravitational waves can
bring information on the number of Universe dimensions. Within the framework of
Kaluza-Klein hypotheses, a different morphology arises between waves generated
before than the compactification process settled down and ordinary
4-dimensional waves. In the former case the scalar and tensor degrees of
freedom can not be resolved. As a consequence if were detected gravitational
waves having the feature here predicted (anomalous polarization amplitudes),
then they would be reliable markers for the existence of an extra dimension.Comment: 5 pages, two figure, to appear on Int. Journ. Mod. Phys.
Rainfall thresholds for the possible occurrence of landslides in Italy
Abstract. In Italy, rainfall is the primary trigger of landslides that frequently cause fatalities and large economic damage. Using a variety of information sources, we have compiled a catalogue listing 753 rainfall events that have resulted in landslides in Italy. For each event in the catalogue, the exact or approximate location of the landslide and the time or period of initiation of the slope failure is known, together with information on the rainfall duration D, and the rainfall mean intensity I, that have resulted in the slope failure. The catalogue represents the single largest collection of information on rainfall-induced landslides in Italy, and was exploited to determine the minimum rainfall conditions necessary for landslide occurrence in Italy, and in the Abruzzo Region, central Italy. For the purpose, new national rainfall thresholds for Italy and new regional rainfall thresholds for the Abruzzo Region were established, using two independent statistical methods, including a Bayesian inference method and a new Frequentist approach. The two methods proved complementary, with the Bayesian method more suited to analyze small data sets, and the Frequentist method performing better when applied to large data sets. The new regional thresholds for the Abruzzo Region are lower than the new national thresholds for Italy, and lower than the regional thresholds proposed in the literature for the Piedmont and Lombardy Regions in northern Italy, and for the Campania Region in southern Italy. This is important, because it shows that landslides in Italy can be triggered by less severe rainfall conditions than previously recognized. The Frequentist method experimented in this work allows for the definition of multiple minimum rainfall thresholds, each based on a different exceedance probability level. This makes the thresholds suited for the design of probabilistic schemes for the prediction of rainfall-induced landslides. A scheme based on four probabilistic thresholds is proposed. The four thresholds separate five fields, each characterized by different rainfall intensity-duration conditions, and corresponding different probability of possible landslide occurrence. The scheme can be implemented in landslide warning systems that operate on rainfall thresholds, and on precipitation measurements or forecasts
Verifica degli impatti socioeconomici ed ambientali conseguenza dei mutamenti climatici in atto nel bacino del Mediterraneo, attraverso l’uso del telerilevamento satellitare
Oggi l’uomo è pericolosamente prossimo ad un punto di non ritorno, in cui può decidere di
cambiare rotta od accettare di vedere avverarsi ciò che più temeva l'economista statunitense Premio
Nobel Paul Robin Krugmani, il quale sosteneva che le future generazioni non avrebbero piĂą potuto
contare, come avevano sempre fatto le precedenti, su di un tenore di vita migliore rispetto a quello
di padri e nonni. Questo potrebbe avvenire perché è stato ormai sollevato il problema dell’assoluta
carenza di risorse naturali, questione che per lungo tempo è stata risolta dai paesi più industrializzati
con l’esclusione della maggioranza della popolazione mondiale dai consumi di massa propri
dell’Occidente. Ma la problematica riguardante questa scarsità segue, ogni giorno di più, quella
altrettanto drammatica che investe il clima e per la comunità scientifica è ormai ovvio che entrambi
sono due facce di una stessa medaglia. Sempre piĂą spesso, dunque, siamo chiamati a confrontarci
non solo con la miseria, in preoccupante aumento in ogni Paese dopo la crisi economica globale
iniziata nel 2008 e non ancora conclusasi, ma, anche, con tematiche come calamitĂ naturali, eventi
estremi, squilibri ecologici, avvenimenti pure essi in apparente, decisa crescita. Privazioni e
mutamenti climatici hanno un costo economico e sociale altissimo e l’unico metodo per risolvere
queste difficoltĂ parrebbe quello di ricondurre la dottrina al significato primigenio della parola
economia, “oikos nomos”, che circa 2700 anni fa significava gestione della casa comune, ovvero la
Terra, pianeta in cui viviamo. In questo contesto è da inquadrare il programma di studio
interministeriale che ha per titolo “Modello integrato per l’evoluzione degli ecosistemi naturali ed
agricoli in relazione ai cambiamenti climatici nell’area mediterranea (FISR-MICENA)”; il lavoro
che qui si presenta è parte integrante dell’attività di ricerca n.19 di questo progetto
Radiogenic isotopes in minerals and melt inclusions reveal that mantle heterogeneity is masked by mixing
Ion diffusion modelling of Fricke-agarose dosemeter gels
In Fricke-agarose gels, an accurate determination of the spatial dose distribution is hindered by the diffusion of ferric ions. In this work, a model was developed to describe the diffusion process within gel samples of finite length and, thus, permit the reconstruction of the initial spatial distribution of the ferric ions. The temporal evolution of the ion concentration as a function of the initial concentration is derived by solving Fick's second law of diffusion in two dimensions with boundary reflections. The model was applied to magnetic resonance imaging data acquired at high spatial resolution (0.3 mm) and was found to describe accurately the observed diffusion effect
Implementing quality by design for biotech products: are regulators on track?
Quality by design (QbD) is an innovative approach to drug development that has started to be implemented into the regulatory framework, but currently mainly for chemical drugs. The recent marketing authorization of the first monoclonal antibody developed using extensive QbD concepts in the European Union paves the way for future further regulatory approvals of complex products employing this cutting-edge technological concept. In this paper, we report and comment on insights and lessons learnt from the non-public discussions in the European Medicines Agency's Biologicals Working Party and Committee for Medicinal Products
for Human Use on the key issues during evaluation related to the implementation of an extensive QbD approach for biotechnology-derived medicinal products. Sharing these insights could prove useful for future developments in QbD for biotech products in general and monoclonal antibodies in particular
Detection of serum allergen-specific IgE in atopic dogs tested in northern Italy: Preliminary study
Canine atopic dermatitis (CAD) is a pruritic allergic skin disease associated with IgE-mediated hypersensitivity. IgE is detected using Serum Allergen-Specific IgE test (SAT) in order to identify allergens. The present study aims to identify the environmental allergens in atopic dogs living in Northern Italy using SAT. The screening SAT (sSAT), using a monoclonal antibody cocktail-based ELISA to identify indoor and outdoor allergens, was performed. In all positive samples, an anti-IgE monoclonal antibody ELISA test was performed to extend panel of allergens. Out of 117 selected dogs, 69 were included in the study; 71% were positive and 29% were negative to sSAT. Among the 49 positive sSAT, 53% were positive for both indoor and outdoor, 38.8% only for indoor, and 8.2% only for outdoor allergens. This is the first study on the frequency of allergens involved in CAD in Italy using SAT. IgE hypersensitivity in atopic dogs of Northern Italy is usually associated with indoor allergens, primarily house dust mites. Among the outdoor allergens, an important role was played by Rumex acetosa. Polysensitization also commonly occurs. Therefore, since the numerous factors affect the IgE positivity in CAD, specific panels for geographical areas should be considered and re-evaluated at time intervals
Amplification and next generation sequencing of near full-length human enteroviruses for identification and characterisation from clinical samples
© 2018, The Author(s). More than 100 different enterovirus (EV) genotypes infect humans and contribute to substantial morbidity. However, current methods for characterisation of full-length genomes are based on Sanger sequencing of short genomic regions, which are labour-intensive and do not enable comprehensive characterisation of viral populations. Here, we describe a simple and sensitive protocol for the amplification and sequencing of near full-length genomes of human EV species using next generation sequencing. EV genomes were amplified from 89% of samples tested, with Ct values ranging between 15.7 and 39.3. These samples included 7 EV-A genotypes (CVA2, 5–7, 10, 16 and EV71), 19 EV-B genotypes (CVA9, CVB1-6, ECHO3, 4, 6, 7, 9, 11, 16, 18, 25, 29, 30, and EV69), 3 EV-C genotypes (CVA19 and PV2, 3) and 1 EV-D genotype (EV70). We characterised 70 EVs from 58 clinical stool samples and eight reference strains, with a minimum of 100X depth. We found evidence of co-infection in four clinical specimens, each containing two distinct EV genotypes (CVB3/ECHO7, CVB3/ECHO18 and ECHO9/30). Characterisation of the complete genome provided conclusive genotyping of EVs, which can be applied to investigate the intra-host virus evolution of EVs, and allows further identification and investigation of EV outbreaks
Cardioplegia and angiotensin II receptor antagonists modulate signal transducers and activators of transcription activation in neonatal rat myocytes.
Previous investigations have shown that the signal transducers and activators of transcription (STATs) signaling pathway play an important role in the modulation of apoptosis after ischemia and reperfusion. The mechanism for this enhanced cardioprotection is unknown, but we believe that alterations STATs may play a role. To investigate this hypothesis, we examined the effects of angiotension II type 1 (AT1) and angiotension II type 2 (AT2) receptor antagonist added to cardioplegia on the downstream response of different STATs, connected with proinflammatory pathways (STAT2, STAT5) and prohypertrophic and antiapoptotic pathways (STAT3). Isolated, nonworking hearts (n = 3 per group) from neonatal rats were perfused aerobically (4°C) for 20 min in the Langendorff mode with the modified St. Thomas' Hospital no. 2 (MSTH2) cardioplegic solution (Group 1), the MSTH2 cardioplegic solution + AT1 receptor antagonist (Group 2), and MSTH2 cardioplegic solution + AT2 receptor antagonist (Group 3). Thus, myocytes were isolated by enzymatic digestion, and STAT2, STAT3, and STAT5 were investigated in Western blot studies. Times to arrest after cardioplegia were 8-12 s for all groups. Total cardioplegia delivery volume was about 300 mL for the 20 min. Perfusion with the MSTH2 cardioplegic solution supplemented with AT1 receptor antagonist (Group 2) induced a significant reduction in STAT2 and STAT5 tyrosine phosphorylation (-58 and -63%, respectively, vs. Group 1, P < 0.05). Conversely, STAT2 and STAT5 activation were unaffected by perfusion with the MSTH2 cardioplegic solution supplemented with AT2 receptor antagonist (Group 3). The decreased activation of STAT2 and STAT5 observed in Group 2 was accompanied by reduction of interleukin-1β (-57% in Group 2 vs. Group 1, P < 0.05). There were no significant differences in STAT3 phosphorylation among all groups. Only the addition of AT1 receptor antagonist to MSTH2 cardioplegia significantly decreases the inflammatory response of the neonatal rat cardiomyocytes without affecting antiapoptotic influence provided by tyrosine phosphorylation of STAT3. AT1 receptor antagonist added to cardioplegia represents an additional modality for enhancing myocardial protection during cardiac surgery and could contribute to optimize the ischemia tolerance of the pediatric heart
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