120,652 research outputs found
L p-convergence of Hermite and Hermite-Fejér interpolation
No full textNecessary and sufficient conditions for the weighted L p-convergence of Hermite and Hermite-Fejér interpolation of higher order based on Jacobi zeros are given, extending previous results for Lagrange interpolation. Error estimates in the weighted L p-norm are also shown. © 2013 Elsevier Inc
First record of Langobardisaurus (Diapsida, Protorosauria) from the Norian (Late Triassic) of Austria, and a revision of the genus
No full textLangobardisaurus Renesto 1994, is a small (body length less than 0.5 m) archosauromorph diapsid with a robust skull set on a very elongate neck (Renesto, 1994). It was originally described based on two fairly well preserved specimens from the Norian Calcare di Zorzino Formation (Zorzino Limestone) of Lombardy (Northwestern Italy), ascribed to L. pandolfii Renesto, 1994. However, the structure of the skull remained virtually unknown until the discovery of a nearly complete and articulated specimen from the Dolomia di Forni Formation (Forni Dolostone) of Friuli, northeastern Italy (Muscio, 1996). That specimen was assigned to a different species, L. tonelloi Muscio 1996, on the basis of the different proportions between some limb elements. Two further specimens referred to Langobardisaurus were reported from the Dolomia di Forni Formation of Friuli (Renesto et al., 2002; Dalla Vecchia, 2006). A third species, L. rossii, also based on a specimen (MFSN 19235) from the Dolomia di Forni Formation of Friuli, was erected by Bizzarrini and Muscio (1995). However Renesto and Dalla Vecchia (2007) demonstrated that L. rossii is instead a lepidosauromorph, probably a rhynchocephalian; so that Langobardisaurus rossii is an invalid taxon
Regge behavior saves string theory from causality violations
No full textHigher-derivative corrections to the Einstein-Hilbert action are present in bosonic string theory leading to the potential causality violations recently pointed out by Camanho et al. We analyze in detail this question by considering high-energy string-brane collisions at impact parameters (the string-length parameter) with (the characteristic scale of the D-brane geometry). If we keep only the contribution of the massless states causality is violated for a set of initial states whose polarization is suitably chosen with respect to the impact parameter vector. Such violations are instead neatly avoided when the full structure of string theory - and in particular its Regge behavior - is taken into account.Higher-derivative corrections to the Einstein-Hilbert action are present in bosonic string theory leading to the potential causality violations recently pointed out by Camanho et al. [1]. We analyze in detail this question by considering high-energy string-brane collisions at impact parameters b ≤ l (the string-length parameter) with l ≫ R (the characteristic scale of the Dp-brane geometry). If we keep only the contribution of the massless states causality is violated for a set of initial states whose polarization is suitably chosen with respect to the impact parameter vector. Such violations are instead neatly avoided when the full structure of string theory — and in particular its Regge behavior — is taken into account.Higher-derivative corrections to the Einstein-Hilbert action are present in bosonic string theory leading to the potential causality violations recently pointed out by Camanho et al. We analyze in detail this question by considering high-energy string-brane collisions at impact parameters (the string-length parameter) with (the characteristic scale of the D-brane geometry). If we keep only the contribution of the massless states causality is violated for a set of initial states whose polarization is suitably chosen with respect to the impact parameter vector. Such violations are instead neatly avoided when the full structure of string theory - and in particular its Regge behavior - is taken into account
On the order of reflection coefficients for Generalized Jacobi weights
No full textThis paper generalizes some results of L. B. Golinskii [4] on the asymptotic behaviour of reflection coefficients associated with generalized Jacobi weight functions. © 2012 Akadémiai Kiadó, Budapest, Hungary
Virus e scuola: riflessioni sui fattori che in Italia hanno acuito le conseguenze dell'emergenza sanitaria [Virus and school: reflections about the factors that have exacerbated the consequences of the health emergency in Italy]
No full textL’Italia è stato il primo dei paesi europei ad essere colpito da una diffusione rapida del virus SARS- Cov-2, nell’arco di 15 giorni è entrata in stato di lockdown. La chiusura delle attività ha riguardato anche le scuole e proprio tale istituzione sociale ha maggiormente sofferto gli effetti negativi del blocco nazionale sia per la mancanza di indicazioni chiare sul da farsi sia per la presenza di carenze e di criticità che da anni l’attraversano. Solo in aprile è iniziata la DaD, la didattica a distanza, ma senza indirizzi metodologici né piani formativi che ne guidassero l’azione, ogni scuola si è organizzata come meglio ha potuto. Nella maggior parte dei casi sono stati gli insegnanti a far andare avanti le cose, mettendo in campo ogni tipo di strategia pur di mantenere un contatto attivo con gli studenti, come dimostrano le testimonianze raccolte attraverso lo strumento focus-group. Ma diversamente dal messaggio che in quei giorni si diffondeva nel nostro Paese, non è andato tutto bene: il virus, vale a dire, ha messo in evidenza una situazione cronica di fragilità e di vulnerabilità, esasperandone le conseguenze e probabilmente proiettandone gli effetti negativi anche negli anni futuri. Scopo del presente lavoro è analizzare quanto accaduto durante il lockdown nel tentativo di inquadrare in una dimensione socio-culturale l’impatto della pandemia. In questo senso verranno presi in considerazioni quei fattori contestuali che hanno avuto un ruolo nell’acuire le conseguenze del virus dal punto di vista educativo.: Italy was the first European country which has been affected by the fast spread of SARS-Cov-2, leading to a general lockdown that started on March 9, 2020, only two weeks after the diagnosis of the Italian patient zero. Such lockdown concerned also the school, that is, the social institution which suffered and keeps suffering the most the negative effects of the national strictions whether because of the lack of precise indications regarding the dactics after the suspension of in-class activities or because of the deficiencies and criticalities that it has been facing since ages. It was only in
ril when teachers could eventually resort to e-learning; though, due to the lack of both methodological indications and adequate study plans, each school acted autonomously and the best they could. In most cases, it was the teachers' initiative and individual efforts that led to a successful didactics. As a matter of fact, teachers tried any kind of strategy to keep in touch actively with their students, as testified through the technique of the focus group. Although, in disagreement with the message of hope spread during the lockdown, not everything has gone well; that is, the virus has highlighted a chronical situation of fragility and vulnerability, whose negative consequences and effects seem to persist also in the future. This essay aims at analysing what happened during the first Italian lockdown framing the impact of the COVID-19 pandemic on a sociocultural dimension. For this purpose, I will take into account the main contextual factors that have contributed to worsen from the didactic and teaching perspective the consequences of the spread of the virus
Collezionismo a Vicenza: la raccolta Vecchia
No full textAttraverso l'inventario giudiziale del 1838, conservato nell'Archivio di Stato di Vicenza, è stato possibile ricostruire più dettagliatamente la preziosa collezione d'arte dell'avvocato Angelo Vecchia (1689-1762) che, nelle sale del suo palazzo vicentino, custodiva opere di G.B. Tiepolo, L. Giordano, G.B. Langetti e P. Liberi. L'inventario rivela anche un nutrito gruppo di sculture e una ricca biblioteca. La passione di Angelo Vecchia per i libri era condivisa anche dal nipote Antonio, antiquario e disegnatore. All'attività di Antonio Vecchia è riservata l'ultima parte del contributo, nel quale sono resi noti alcuni inediti documenti d'archivio
Il paesaggio vegetazionale dell’insediamento etrusco (V sec. a.C.) di Miseria Vecchia, Mirandola, 9-10 m s.l.m. (Modena, Nord-Italia).
No full textRicostruzine del paesaggio vegetale dell'abitato etrusco di Miseria Vecchia attraverso le analisi botaniche, Il sito sorgeva in un paesaggio vegetazionale aperto, in un'area interessata da formazioni erbacee con tratti palustri. I querceti mesoigrofili hanno poco rilievo. Sono presenti coltivazioni di Cereali e Vite
Cardiac autonomic adjustement to normal human pregnancy : insight from spectral analysis of R-R interval and systolic arterial pressure variability
No full textOBJECTIVE: To assess the adaptation in autonomic control mechanisms that accompanies the marked haemodynamic changes, such as increases in cardiac size and output, that occur in the course of normal human pregnancy. DESIGN: We studied 14 healthy pregnant women (aged 30+/-1 years) before the 6th week (early stage) and within weeks 32-34 (late stage) of pregnancy, while they were at rest or in a state of active orthostatism (standing), which enhances sympathetic activity. METHODS: We used echocardiography to assess cardiac volumes and mass, and spectral analysis of the R-R interval and systolic arterial pressure variability to obtain indices of autonomic regulation of the circulation. This non-invasive methodology, recently validated with direct recordings of muscle sympathetic nerve activity, furnishes quantitative markers of sympathetic modulation of the sino-atrial node (low frequency component, LF in normalized units, nu), vagal modulation (high frequency component, HF in normalized units, nu) and the overall arterial pressure-heart rate baroreflex gain (alpha index). RESULTS: Late pregnancy was characterized by an increase in cardiac size and volumes and by a reduction of R-R interval, R-R interval variance and the alpha index, together with an increase in the LF/HF ratio (from 1.4+/-0.4 to 5.6+/-1.9). Changes in markers of autonomic modulation of the sino-atrial node normally induced by the standing position were blunted. CONCLUSIONS: The late stage of normal human pregnancy appears to be characterized by alterations in the autonomic control of the circulation and by attenuated responsiveness to active standing, possibly as a consequence of the accompanying increase in cardiac size
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