114,359 research outputs found
Spatial Moments for Colloid-Enhanced Radionuclide Transport in Heterogeneous Aquifers
No full textWe consider colloid facilitated radionuclide transport by steady groundwater flow in a heterogeneous porous formation. Radionuclide
binding on colloids and soil-matrix is assumed to be kinetically/equilibrium controlled. All reactive parameters are regarded as uniform,
whereas the hydraulic log-conductivity is modelled as a stationary random space function (RSF). Colloid-enhanced radionuclide transport
is studied by means of spatial moments pertaining to both the dissolved and colloid-bounded concentration. The general expressions of
spatial moments for a colloid-bounded plume are presented for the first time, and are discussed in order to show the combined impact of
sorption processes as well as aquifer heterogeneity upon the plume migration. For the general case, spatial moments are defined by the aid
of two characteristic reaction functions which cannot be expressed analytically. By adopting the approximation for the longitudinal fluid
trajectory covariance valid for a flow parallel to the formation bedding suggested by Dagan and Cvetkovic [Dagan G, Cvetkovic V. Spatial
Moments of Kinetically Sorbing Plume in a Heterogeneous Aquifers. Water Resour Res 1993;29:4053], we obtain closed form solutions.
For illustrative purposes, we consider the case when sorption/desorption between solution and moving colloids is a linear non-equilibrium
process, whereas sorption onto the soil-matrix is a linear equilibrium process. Based on the flow and transport parameters pertaining
to the alluvial aquifer at the Yucca Mountain Site (Nevada), we investigate the potential enhancing role of colloidal particles by
comparing radionuclide spatial moments with and without colloids, and mainly investigate the sensitivity to the reverse rate parameter.
The most potentially significant effects are obtained when radionuclide attachment to colloidal particles is irreversible. The simplicity of
our results makes them suitable for quick assessments of the potential impact of colloids on contaminant transport in heterogeneous
aquifers
An Approach to the Assessment of Domino Accidents Hazard in Quantitative Area Risk Analysis
No full textOn The Velocity Covariance for Steady Flows in Heterogeneous Porous Formations and Its Applications To Contaminants Transport
No full textWe consider groundwater steady flow in a heterogeneous porous formation of random
and stationary log-conductivity Y = ln K, characterized by the mean bY À, and the two point
correlation function CY which in turn has finite, and different horizontal and vertical integral
scales I and Iv, respectively. The fluid velocity V, driven by a given head drop applied at the
boundary, has constant mean value U K (U, 0, 0). Approximate explicit analytical expressions
for transverse velocity covariances are derived. The adopted methodology follows
the approach developed by Dagan and Cvetkovic (Spatial moments of kinetically sorbing
plume in a heterogeneous aquifers, Water Resour. Res. 29 (1993) 4053) to obtain a similar
result for the longitudinal velocity covariance. Indeed, the approximate covariances of
transverse velocities are determined by requiring that they have the exact first order variances
as well as zero integral scale (G. Dagan, Flow and Transport in Porous Formations
(Springer, 1989)) , and provide the exact asymptotic limits of the displacement covariance of
the fluid particles obtained by Russo (On the velocity covariance and transport modeling in
heterogeneous anisotropic porous formations 1. Saturated flow, Water Resour. Res., 31
(1995) 129). Comparisons with numerical results show that the proposed expressions compare
quite well in the early time regime, and for Ut/I >100. Since most of the applications,
like assessing the effective mobility of contaminants or quantifying the potential hazards of
nuclear repositories, require predictions over higher times the proposed approximate expressions
provide acceptable results. The main advantage related to such expressions is that
they allow obtaining closed analytical forms of spatial moments pertaining to kinetically
sorbing contaminant plumes avoiding the very heavy computational effort which is generally
demanded. For illustration purposes, we consider the movement of one contaminant
species, and show how our approximate spatial moments compare with the numerical
simulations
NOTA SULLE MODALITA' DELL'ESSERE
No full textL'intervento contiene una valutazione del contributo di Emanuele Severino alla riproposta - dopo le critiche neopositivistiche e analitiche - della perenne pertinenza di un discorso esplicitamente ontologico. Ricostruisce poi le ragioni che vietano alla ontologia di Severino di sviluppare una compiuta dottrina delle modalità. Difende, infine, la figura della "contingenza" dalle critiche classicamente emerse nei suoi riguardi
L'economia del futuro comincia dalla città
No full texti flussi creativi dentro le città e il grado di attrattività dei talenti da parte del territori
Analysis of secreted proteins
No full textMost biological processes including growth, proliferation, differentiation, and apoptosis are coordinated by tightly regulated signaling pathways, which also involve secreted proteins acting in an autocrine and/ or paracrine manner. In addition, extracellular signaling molecules affect local niche biology and in fl uence the cross-talking with the surrounding tissues. The understanding of this molecular language may provide an integrated and broader view of cellular regulatory networks under physiological and pathological conditions. In this context, the pro fi ling at a global level of cell secretomes (i.e., the subpopulations of a proteome secreted by the cell) has become an active area of research. The current interest in secretome research also deals with its high potential for the biomarker discovery and the identi fi cation of new targets for therapeutic strategies. Several proteomic and mass spectrometry platforms and methodologies have been applied to secretome pro fi ling of conditioned media of cultured cell lines and primary cells. Nevertheless, the analysis of secreted proteins is still a very challenging task, because of the technical dif fi culties that may hamper the subsequent mass spectrometry analysis. This chapter describes a typical work fl ow for the analysis of proteins secreted by cultured cells. Crucial issues related to cell culture conditions for the collection of conditioned media, secretome preparation, and mass spectrometry analysis are discussed. Furthermore, an overview of quantitative LC-MS-based approaches, computational tools for data analysis, and strategies for validation of potential secretome biomarkers is also presented
Tabla genealógica de la familia de San Severino, príncipe de Bisignano. [Manuscrito]
No full textEmpieza en Antonio de San Severino, V conde de Tricarico, duque de San Marco.
Termina en sus quintos nietos Pedro Antonio de Blanca y San Severino, IV marqués de la Vala Siciliana, y doña Julia Ursinos y San Severino, princesa de Bisignano, duquesa de San Marco.Pertenece a la Colección Salazar y Castro de la RA
Tabla genealógica de la familia de San Severino, príncipe de Bisignano. [Manuscrito]
No full textEmpieza en Antonio de San Severino, V conde de Tricarico, duque de San Marco.
Termina en sus quintos nietos Pedro Antonio de Blanca y San Severino, IV marqués de la Vala Siciliana, y doña Julia Ursinos y San Severino, princesa de Bisignano, duquesa de San Marco.Pertenece a la Colección Salazar y Castro de la RA
author-bios-SRD-19-0063.R1 – Supplemental material for The Network Structure of Police Misconduct
No full textSupplemental material, author-bios-SRD-19-0063.R1 for The Network Structure of Police Misconduct by George Wood, Daria Roithmayr and Andrew V. Papachristos in Socius</p
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