170,384 research outputs found
On the asymptotic boundedness of the energy of solutions of the wave equation
No full textApplying a class of quadratic forms introduced by Manfrin we study the asymptotic behavior, as t → +∞, of the energy of the solutions to the Cauchy problem for wave equations with time dependent propagation speed
Eradicate Invasive Louisiana Red Swamp and Preserve Native white Clawed Crayfish in Friuli Venezia Giulia
No full textOn a theorem by Sohr for Navier-Stokes equations
No full textIn this paper we study some criteria for the full (space-time) regularity of weak solutions to the Navier-Stokes equations. In particular, we generalize some classical and very recent criteria involving the velocity, or its
derivatives. More specifically, we show with elementary tools that if a weak solution, or its vorticity, is small in
appropriate Marcinkiewicz spaces, then it is regular
Propagation of analyticity in the C∞ solutions of quasi-linear weakly hyperbolic wave equations
No full textdepartmental bulletin pape
Studi sulla tradizione manoscritta dell'Eutifrone di Platone: la prima famiglia
No full textIl contributo analizza un ramo della tradizione manoscritta dell’Eutifrone di Platone, dialogo trasmesso nella sua interezza da sessanta testimoni (ante 1600), cui si aggiungono gli excerpta dotati di valore primario del Vat. Pal. 173 (P). La prima famiglia comprende tre manoscritti primari, Bodl. Clarke 39 (B, a. 895), Tubing. Mb 14 (C, XI sec.), Marc. gr. 185 (D, XI o XII sec.), e tredici apografi, di ciascuno dei quali si fornisce in apertura una breve descrizione: se ne esaminano in seguito i rapporti stemmatici che intercorrono tra di loro sulla base di nuove collazioni. Per quanto riguarda l’Eutifrone, B non ha avuto discendenza, mentre la discendenza di C è limitata al solo Laur. Plut. 89 sup. 78 prodotto in ambiente crisolorino: nuovi elementi sono stati individuati riguardo alla storia di C. Tutti i restanti apografi derivano da D, a seguito di ciascuna delle tre stratificazioni diortotiche che hanno interessato il manoscritto, due delle quali ne hanno contaminato il testo con lezioni delle altre due famiglie. Da D+D2 fu copiato un testimone interessante seppure per lo più ignorato dagli studiosi, il Bonon. gr. 3630. Gli apografi di D+D2+d1 si dividono in due ramificazioni: il ‘ramo α’ comprende lo Haun. gr. Gks 415a, 2° e i suoi discendenti Ambros. N 269 sup., e Par. gr. 2011; il ‘ramo ε’ è costituito dal Par. gr. 1810, con la sua copia Laur. Conv. Soppr. 103, dal Vat. gr. 229 e dal Par. gr. 2010, col suo discendente Par. Suppl. gr. 69. Dopo l’ultima diorthosis di d2, D fu copiato da Demetrio Trivolis nell’Esc. Ψ. I. 1, a sua volta modello del Bern. 579, in parte collegato a Costantino Lascaris
Reproductive plasticity of a Procambarus clarkii population living 10°C below its thermal optimum
No full textIn this study the annual reproductive biology of a Procambarus clarkii (Girard, 1852) population living in an atypical habitat with cold spring waters is investigated by monitoring Gonado-Somatic and Hepato-Somatic Indexes (GSI and HSI) and by performing cytology on ovaries. Despite its known preference for habitats with water temperature from 21 to 30 °C, our results clearly confirm the adaptation of this population to the atypical thermal habitat, characterised by an annual mean water temperature value of 13.32 ±0.08 °C. Maximum gonadal development was reached in August, with maximum GSI median value of 0.64 (instead of reported values even 10 times higher for other populations), and ovigerous females were found in autumn, with mean realized fecundity of 35 ±7 compared to 285–995 reported from other habitats. Histological analysis was consistent with other studies and allowed us to follow ovarian development at cytological level. The importance of all these results is not to be underestimated: to our knowledge these findings are the first report of the coolest habitat successfully colonized by this species at the present time and so they have to be taken as a warning about the possible range expansion of P. clarkii also to northern and colder habitats that have few things in common with the native habitat of the species and, up to now, were considered “safe” from the invasion of the red swamp crayfish
Sviluppo e applicazione di biotecnologie genomiche in mitilo per il controllo della contaminazione da biotossine algali in stock alimentari
No full textFormation of singularities for weakly non-linear NxN hyperbolic systems
No full textWe present some results on the formation of singularities for C^1 -solutions of the quasi-linear N × N strictly hyperbolic system
U_t + A(U )U_x = 0 in [0, +∞) × R_x . Under certain weak non-linearity conditions (weaker than genuine non-linearity), we prove that the first order derivative of the solution blows-up in finite time
Notes on a paper of Pokhozhaev
No full textWe prove a second order identity for the Kirchhoff equation which yields, in
particular, a simple and direct proof of Pokhozhaev's second order conservation
law when the nonlinearity has the special form . As
applications, we give: an estimate of order for the lifespan
of the solution of the Cauchy problem with initial data of size
in Sobolev spaces when the nonlinearity is given by any
function ; a necessary and sufficient condition for boundedness of a
second order energy of the solutions.Comment: 7 page
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