Multidimensional stochastic differential equations with distributional drift

This paper investigates a time-dependent multidimensional stochastic differential equation with drift being a distribution in a suitable class of Sobolev spaces with negative derivation order. This is done through a careful analysis of the corresponding Kolmogorov equation whose coefficient is a distribution

Expression of platelet-derived growth factor-beta receptor and bovine papillomavirus E5 and E7 oncoproteins in equine sarcoid.

Equine sarcoids are benign fibroblastic skin tumours that are recognized throughout the world. Infection with bovine papillomavirus (BPV) types 1 and 2 has been implicated as a major factor in disease development; however, the cellular mechanisms underlying fibroblast transformation remain poorly defined. The present study further characterizes aspects of the association with BPV in 15 equine sarcoids. BPV DNA was demonstrated in 12/15 tumours collected from different areas of Italy. Nine of these 12 tumours expressed the BPV oncoproteins E5 and E7, but these oncoproteins were not expressed by normal equine cells. The BPV E5 protein is known to bind to the platelet-derived growth factor-b receptor (PDGF-bR) and this molecule was expressed by 11 of the 12 sarcoids in which E5 was demonstrated. These findings add further weight to the theory that BPV and the PDGF-bR may have a role in the pathogenesis of this disease

On the regularity of stochastic currents, fractional Brownian motion and applications to a turbulence model

38 pagesInternational audienceWe study the pathwise regularity of the map $$\varphi \mapsto I(\varphi) = \int_0^T \langle \varphi(X_t), dX_t \rangle$$ where $\varphi$ is a vector function on $\R^d$ belonging to some Banach space $V$, $X$ is a stochastic process and the integral is some version of a stochastic integral defined via regularization. A \emph{stochastic current} is a continuous version of this map, seen as a random element of the topological dual of $V$. We give sufficient conditions for the current to live in some Sobolev space of distributions and we provide elements to conjecture that those are also necessary. Next we verify the sufficient conditions when the process $X$ is a $d$-dimensional fractional Brownian motion (fBm); we identify regularity in Sobolev spaces for fBm with Hurst index $H \in (1/4,1)$. Next we provide some results about general Sobolev regularity of Brownian currents. Finally we discuss applications to a model of random vortex filaments in turbulent fluids

CONODONT BIOSTRATIGRAPHY OF THE S.CASSIANO FORMATION SURROUNDING THE SELLA MASSIF (DOLOMITES, ITALY): IMPLICATIONS FOR SEQUENCE STRATIGRAPHIC MODELS OF THE TRIASSIC OF THE SOUTHERN ALP

The stratigraphy and age of the S.Cassiano Formation outcropping around the Sella Massif (Dolomites, Northern Italy) were investigated. The unit interfingers with slope deposits pertaining to the Cassian carbonate platform of the Sella Massif. Several stratigraphic sections were analyzed from a sedimentologic and biostratigraphic perspective.Three section (Sella Pass Ia and Ib,Gardena Pass) yielded stratigraphically significant conodont faunas referable to the diebeli Assemblage Zone sensu Krystyn (1983) of latest Ladinian age. Therefore, the Sella Cassian Platform traditionally regarded as a typical Carnian buildup, is also latest Ladinian age. The occurrence of the post-volcanic carbonate platforms older (e.g.Denti di Terra Rossa) and younger (e.g.,the Nuvolau and Lagazuoi platform) than the Sella Platform,suggest that :a) the post-volcanic and Cassian succession of the Dolomites is fare more complex than traditionally thought and b) a sequence stratigraphic model of the Middle-Upper Triassic of the Dolomites based on two generations of Cassian platforms is clearly inadequate to describe the actual succession. &nbsp

Infinite-dimensional calculus under weak spatial regularity of the processes

Two generalizations of Itô formula to infinite-dimensional spaces are given. The first one, in Hilbert spaces, extends the classical one by taking advantage of cancellations when they occur in examples and it is applied to the case of a group generator. The second one, based on the previous one and a limit procedure, is an Itô formula in a special class of Banach spaces having a product structure with the noise in a Hilbert component; again the key point is the extension due to a cancellation. This extension to Banach spaces and in particular the specific cancellation are motivated by path-dependent Itô calculus

Syndepositional cements associated with nannofossils in the Marmolada Massif: Evidences of microbially mediated primary marine cements? (Middle Triassic, Dolomites, Italy)

The Marmolada platform is characterized by striking globose masses (“evinosponges”), arranged in concentric bands, of fibrous calcite cements ranging in size from centimeters to several decimeters. The lithogenetic importance of these peculiar cements has been recognized in many Middle Triassic buildups of the Western Tethys. EDS microanalyses revealed that these fibrous cements contain 1–3 mol% of Mg and detectable amounts of Sr, over 1000 ppm, sometimes exceeding 10,000 ppm. The strontium geochemical signature in neomorphic calcite could reflect the replacement of an aragonitic carbonate precursor. The boundaries between the fibrous calcite bands are marked by alignments of microcrystalline aggregates of fluorapatite and/or dolomite. The presence of fluorapatite may indicate a depositional microenvironment eutrophic or rich in microbial communities. Epifluorescence analyses showed bright bands alternated to dark ones, confirming that organic matter remains occur within the studied cements and could have played a significant role in supporting the widespread syndepositional cementation. High magnification SEM observations on bright epifluorescent bands showed the presence of widespread, more or less spherical bodies ranging in size 100–300 nm. These bodies could represent the relicts of nannobacterial cells