A new equation for macroscopic description of capillary rise in porous media

Capillary rise in porous media is frequently modeled using the Washburn equation. Recent accurate measurements of advancing fronts clearly illustrate its failure to describe the phenomenon in the long term. The observed underprediction of the position of the front is due to the neglect of dynamic saturation gradients implicit in the formulation of the Washburn equation. We consider an approximate solution of the governing macroscopic equation, which retains these gradients, and derive new analytical formulae for the position of the advancing front, its speed of propagation, and the cumulative uptake. The new solution properly describes the capillary rise in the long term, while the Washburn equation may be recovered as a special case. (C) 2004 Elsevier Inc. All rights reserved.

The New (Marketing) Role of Firms as Media Content Providers – The case of SME’s Strategic Social Media Presence

In the new social media context, it is gradually more common to say that each party can itself be considered a media content provider, firms included (through their brand pages). This tendency is reflected in a rising professional field called “content marketing”. This study incorporates the perspective of small and medium-sized enterprises (SMEs) into the scope of social media (SM) as a marketing communications and media content distribution system. In an exploratory content analysis of 20 official SM brand pages with 1281 analyzed posts the authors study how SMEs respond to the advent of a new paradigm of marketing communications with special attention to their usage of media-specific contents. SM impels companies to eventually rethink the traditional one-way communication flow of their marketing messages and to incorporate a new, two-way communication into their marketing strategy, where (their engaged and involved) users can create, modify, share and discuss content related to the firm’s activity. This study’s preliminary results show that diffusing content generally acts for SMEs as a facilitator to involve fans by offering a thematized space for them to manifest themselves in company-related topics. Therefore, content adds to the firms’ possibilities of brand positioning by offering a reflection of fans’ company- and contentrelated behavior, which is a supplementary source of information.

The Prison System and the Media: How “Orange Is The New Black” Engages with the Prison as a Normalizing Agent

The purpose of this project is to ascertain the ways in which Orange is the New Black uses its platform to either complicate or reify narratives about the prison system, prisoners and their relationship to the state. This research uses the works of Giorgio Agamben, Colin Dayan, Michelle Alexander and Lisa Guenther to situate the ways the state uses the prison and social narratives about the prison to extend its control on certain populations beyond prison walls through police presence, parole, the war on drugs and prison fees. From that basis, this work argues that while Orange does challenge some narratives about race and sexuality, because of its reliance on “bad choices” as a humanizing trope and its reliance on certain racialized stereotypes for entertainment, the show ultimately does more to reify existing narratives that support state interests.

Susan Kleckner (left), filmmaker with multi-media artist Alida Walsh (right) at Cerridwen Salon in New York

: Title and date provided by Freda Leinwand.

“Refugee Voices,” New Social Media and Politics of Representation: Young Congolese in the Diaspora and Beyond

This article examines the role of new social media in the articulation and representation of the refugee and diasporic “voice.” The article problematizes the individualist, de-politicized, de-contextualized, and aestheticized representation of refugee/diasporic voices. It argues that new social media enable refugees and diaspora members to exercise agency in managing the creation, production, and dissemination of their voices and to engage in hybrid (on- and offline) activism. These new territories for self-representation challenge our conventional understanding of refugee/diaspora voices. The article is based on research with young Congolese living in the diaspora, and it describes the Geno-cost project created by the Congolese Action Youth Platform (CAYP) and JJ Bola’s spoken-word piece, “Refuge.” The first shows agency in the creation of analytical and activist voices that promote counter-hegemonic narratives of violence in the eastern Democratic Republic of Congo, while the second is an example of aesthetic expressions performed online and offline that reveal agency through authorship and ownership of one’s voice. The examples highlight the role that new social media play in challenging mainstream politics of representation of refugee/diaspora voices.

A new method for conditioning stochastic groundwater flow models in fractured media

Many geological formations consist of crystalline rocks that have very low matrix permeability but allow flow through an interconnected network of fractures. Understanding the flow of groundwater through such rocks is important in considering disposal of radioactive waste in underground repositories. A specific area of interest is the conditioning of fracture transmissivities on measured values of pressure in these formations. This is the process where the values of fracture transmissivities in a model are adjusted to obtain a good fit of the calculated pressures to measured pressure values. While there are existing methods to condition transmissivity fields on transmissivity, pressure and flow measurements for a continuous porous medium there is little literature on conditioning fracture networks. Conditioning fracture transmissivities on pressure or flow values is a complex problem because the measurements are not linearly related to the fracture transmissivities and they are also dependent on all the fracture transmissivities in the network. We present a new method for conditioning fracture transmissivities on measured pressure values based on the calculation of certain basis vectors; each basis vector represents the change to the log transmissivity of the fractures in the network that results in a unit increase in the pressure at one measurement point whilst keeping the pressure at the remaining measurement points constant. The fracture transmissivities are updated by adding a linear combination of basis vectors and coefficients, where the coefficients are obtained by minimizing an error function. A mathematical summary of the method is given. This algorithm is implemented in the existing finite element code ConnectFlow developed and marketed by Serco Technical Services, which models groundwater flow in a fracture network. Results of the conditioning are shown for a number of simple test problems as well as for a realistic large scale test case.

The right to the screen: from media education to educommunication in Brazil

Nowadays in Brazil, some social organizations, governments and mass media are discussing the need to establish an oversight committee to guarantee the quality of television programmes, as well as the need to set a system to determine what kind of pro, gram is appropriate for every television time slot. Across Brazil, a representative body of children and young people have come to the conclusion that the right to receive quality television programmes is not enough. The children of the new generations think they have the right to access new technologies and the production of their own messages, in accordance with their own creativity, interests and lifestyle projects within society.

The right to screens: from media education to educommunication in Brazil

Social organizations, local governments and the media in Brazil are confronting them, selves over the need for an oversight board to guarantee quality television programming, and establishing a system to determine which television programs are appropriate for which television time slots. Across Brazil, a representative body of children and young adults have determined that the right to receive quality programming is not currently being met. Children of the new generation see themselves as having a right to access new technologies which enable them to produce their own messages according to their own creativity, interests, and social participation. This new generation wants to go beyond education in order to watch and conquer their ""right to screens"".

Polydimethylsiloxane: a new contrast material for localization of occult breast lesions

Background. The radioguided localization of occult breast lesions (ROLL) technique often utilizes iodinated radiographic contrast to assure that the local injection of (99m)Tc-MAA corresponds to the location of the lesion under investigation. However, for this application, this contrast has several shortcomings. The objective of this study was to evaluate the safety, effectiveness and technical feasibility of the use of polydimethylsiloxane (PDMS) as radiological contrast and tissue marker in ROLL. Materials and methods. The safety assessment was performed by the acute toxicity study in Wistar rats (n = 50). The radiological analysis of breast tissue (n = 32) from patients undergoing reductive mammoplasty was used to verify the effectiveness of PDMS as contrast media. The technical feasibility was evaluated through the scintigraphic and histologic analysis. Results. We found no toxic effects of PDMS for this use during the observational period. It has been demonstrated in human breast tissue that the average diameter of the tissue marked by PDMS was lower than when marked by the contrast medium (p <0.001). PDMS did not interfere with the scintigraphic uptake (p = 0.528) and there was no injury in histological processing of samples. Conclusions. This study demonstrated not only the superiority of PDMS as radiological contrast in relation to the iodinated contrast, but also the technical feasibility for the same applicability in the ROLL.

A New Approach for Video Adaptation through Overlay Services Networks

Video adaptation is an extensively explored content providing technique aimed at appropriately suiting several usage scenarios featured by different network requirements and constraints, user`s terminal and preferences. However, its usage in high-demand video distribution systems, such as CNDs, has been badly approached, ignoring several aspects of optimization of network use. To address such deficiencies, this paper presents an approach for implementing the adaptation service by exploring the concept of overlay services networks. As a result of demonstrate the benefits of this proposal, it is made a comparison of this proposed adaptation service with other strategies of video adaptation.

New Analytic Solution Related to the Richards, Philip, and Green-Ampt Equations for Infiltration

Based on physical laws of similarity, an analytic solution of the soil water potential form of the Richards equation was derived for water infiltration into a homogeneous sand. The derivation assumes a similarity between the soil water retention function and that of the soil water content profiles taken at fixed times. The new solution successfully described soil water content profiles experimentally measured for water infiltrating downward, upward, and horizontally into a homogeneous sand and agrees with that presented by Philip in 1957. The utility of this analysis is still to be verified, but it is expected to hold for soils that have a narrow pore-size distribution before wetting and that manifest a sharp increase of water content at the wetting front during infiltration. The effect of van Genuchten`s parameters alpha and n on the application of the solution to other porous media was investigated. The solution also improves and provides a more realistic description of the infiltration process than that pioneered by Green and Ampt in 1911.

Refractive index tomography of turbid media by bifocal optical coherence refractometry

We demonstrate tomographic imaging of the refractive index of turbid media using bifocal optical coherence refractometry (BOCR). The technique, which is a variant of optical coherence tomography, is based on the measurement of the optical pathlength difference between two foci simultaneously present in a medium of interest. We describe a new method to axially shift the bifocal optical pathlength that avoids the need to physically relocate the objective lens or the sample during an axial scan, and present an experimental realization based on an adaptive liquid-crystal lens. We present experimental results, including video clips, which demonstrate refractive index tomography of a range of turbid liquid phantoms, as well as of human skin in vivo.

The cell biology of atherosclerosis - new developments

In the development of atherosclerotic lesions, three basic processes occur: 1) invasion of the artery wall by leucocytes, particularly monocytes and T-lymphocytes; 2) smooth muscle phenotypic modulation, proliferation, and synthesis of extracellular matrix; and 3) intracellular (macrophage and smooth muscle) lipoprotein uptake and lipid accumulation. Invasion of the vessel wall by leucocytes is mediated through the expression of adhesion molecules on both leucocytes and the endothelium making them 'sticky'. The adhesion molecules are induced by high serum cholesterol levels or complement fragments. Leucocytes which have adhered to the endothelium are chemo-attracted into the vessel wall by cytokines produced by early arriving leucocytes or by low density lipoprotein which has passively passed into the wall, in the process being trapped and oxidised. The oxidised low density lipoprotein is taken up by scavenger receptors (which are not subject to down-regulation) on both macrophages and smooth muscle cells. The overaccumulation of lipid is toxic to the cells and they die contributing to the central necrotic core. The macrophages and T-lymphocytes produce substances which induce smooth muscle cells of the artery wall to change from a 'contractile' (high volume fraction of myofilaments [V(v)myo]) to a 'synthetic' (low V(v)myo) phenotype. In this altered state they respond to growth factors released from macrophages, platelets, regenerating endothelial cells and smooth muscle cells; produce large amounts of matrix; express lipoprotein scavenger receptors; express adhesion molecules for leucocytes; and express HLA-DR following exposure to the T-lymphocyte product, IFN-delta, suggesting that they can become involved in a generalised immune reaction.