Streaming Current and Streaming Potential Induced by Water Flow Through Porous Media

This study was conducted to investigate analytically and experimentally the relationship between the rate of flow of water through porous material and the streaming current and streaming potential induced by this flow. The effect of dissolved salts in the permeating solution and the size of the soil particles was also investigated. Results and conclusions of this study are summarized as follows: A modified procedure using the appropriate delay to insure stead state conditions was used for the measurements of both streaming current and streaming potential. The flow-pressure relationship was the same irrespective of the counter electro-osmosis (resulting from the streaming potential) and the change in salt concentration. Flows through the samples tested thus followed Darcy\u27s Law. The rate of flow (at a constant salt concentration and soil particle diameter) is directly proportional to the induced streaming current and streaming potential. Emperical equations in the form of I = C1q and E = C2q are suggested. A decrease in both streaming current and streaming potential was observed with increase of salt concentrate in the permeating solution. Comparable results were obtained for simulated natural waters and NaCl and KCl solutions, provided that the conductance of the solution was taken as a parameter. A decrease in current and potential was observed with increase of soil particle diameter. a Relationships of the form α = bN and β = C log N + d are suggested to express the effects of particle size and salt concentration on the streaming current and the streaming potential induced by the flow. Induced streaming potential was found to increase with the decrease in temperature. The analytical relationships developed together with the experimental work could probably be used as the basis of a method for measuring the rate of flow through porous material

New challenges in wireless and free space optical communications

AbstractThis manuscript presents a survey on new challenges in wireless communication systems and discusses recent approaches to address some recently raised problems by the wireless community. At first a historical background is briefly introduced. Challenges based on modern and real life applications are then described. Up to date research fields to solve limitations of existing systems and emerging new technologies are discussed. Theoretical and experimental results based on several research projects or studies are briefly provided. Essential, basic and many self references are cited. Future researcher axes are briefly introduced

Today’s Consumption in Egypt

During the last decade Cairo has witnessed a flowering of shopping malls, ATM and mobile phone use, resort-style recreation, and fast-food consuming, all of which represent a radical departure from previous Egyptian consumer habits. These new behaviours symbolize Egypt’s increasing integration into the world capitalist system, if not its growing participation in multiple dimensions of globalization

Perceptions of cUrfi Marriage in the Egyptian Press

Recent press coverage of what has been coined as 'curfi marriage' seems to bear witness to evolving sexual norms in Egyptian society today. More than to the phenomenon itself, for which no serious statistics are available, our attention should be drawn to the labelling procedures indulged by the press and 'popular literature'. Perceptions of sexuality and curfi marriage, and the way in which society is portrayed, reflect an attempt to incorporate the changing norms within a revived Islamic code. Reading the press, one discovers with astonishment an unleashed resentment of and blame on the youth and women

c-Jun N-terminal kinase has a key role in Alzheimer disease synaptic dysfunction in vivo.

Altered synaptic function is considered one of the first features of Alzheimer disease (AD). Currently, no treatment is available to prevent the dysfunction of excitatory synapses in AD. Identification of the key modulators of synaptopathy is of particular significance in the treatment of AD. We here characterized the pathways leading to synaptopathy in TgCRND8 mice and showed that c-Jun N-terminal kinase (JNK) is activated at the spine prior to the onset of cognitive impairment. The specific inhibition of JNK, with its specific inhibiting peptide D-JNKI1, prevented synaptic dysfunction in TgCRND8 mice. D-JNKI1 avoided both the loss of postsynaptic proteins and glutamate receptors from the postsynaptic density and the reduction in size of excitatory synapses, reverting their dysfunction. This set of data reveals that JNK is a key signaling pathway in AD synaptic injury and that its specific inhibition offers an innovative therapeutic strategy to prevent spine degeneration in AD

Stimulation of translation by human Unr requires cold shock domains 2 and 4, and correlates with poly(A) binding protein interaction

The RNA binding protein Unr, which contains five cold shock domains, has several specific roles in post-transcriptional control of gene expression. It can act as an activator or inhibitor of translation initiation, promote mRNA turnover, or stabilise mRNA. Its role depends on the mRNA and other proteins to which it binds, which includes cytoplasmic poly(A) binding protein 1 (PABP1). Since PABP1 binds to all polyadenylated mRNAs, and is involved in translation initiation by interaction with eukaryotic translation initiation factor 4G (eIF4G), we investigated whether Unr has a general role in translational control. We found that Unr strongly stimulates translation in vitro, and mutation of cold shock domains 2 or 4 inhibited its translation activity. The ability of Unr and its mutants to stimulate translation correlated with its ability to bind RNA, and to interact with PABP1. We found that Unr stimulated the binding of PABP1 to mRNA, and that Unr was required for the stable interaction of PABP1 and eIF4G in cells. siRNA-mediated knockdown of Unr reduced the overall level of cellular translation in cells, as well as that of cap-dependent and IRES-dependent reporters. These data describe a novel role for Unr in regulating cellular gene expression

Selfies for Mobile Biometrics: Sample Quality in Unconstrained Environments

Taking a ‘selfie’ using a mobile device has become a natural gesture in everyday life. This simple action has many similarities to face authentication on a smartphone: positioning the camera, adjusting the pose, choosing the right background and looking for the best lighting conditions. In the context of face authentication, most of the standardised processes and best practice for image quality is mainly focused on passport images and only recently has the attention of research moved to mobile devices. There is a lack of an agile methodology that adapts the characteristics of facial images taken on smartphone cameras in an unconstrained environment. The main objective of our study is to improve the performances of facial verification systems when implemented on smartphones. We asked 53 participants to take a minimum of 150 ‘selfies’ suitable for biometric verification on an Android smartphone. Images were considered from constrained and unconstrained environments, where users took images both in indoor and outdoor locations, simulating real-life scenarios. We subsequently calculated the quality metrics for each image. To understand how each quality metric affected the authentication outcome, we obtained biometric scores from the comparison of each image to a range of images. Our results describe how each quality metric is affected by the environment variations and user pose using the biometric scores obtained. Our study is a contribution to improve the performance and the adaptability of face verification systems to any environmental conditions, applications and devices

Bullets over ballots: Islamist groups, the state and electoral violence in Egypt and Morocco

This article is concerned with state-sponsored electoral violence in liberalized autocracies. The first section of the paper identifies a number of variables that can help explain the decision calculus of authoritarian incumbents to deploy force against strong electoral challengers. The second section then examines these propositions with reference to Egypt and Morocco. Drawing on recent parliamentary elections in both countries the article questions why, despite facing the challenge of political Islam, the two regimes differed so markedly in their willingness to manipulate the polls by recourse to violence. Whilst the Egyptian authorities decided to abrogate all pretence of peaceful elections in favour of violent repression against the Muslim Brotherhood candidates and sympathizers, no such tactics were deployed by the ruling elite in Morocco. We suggest that three principal factors influenced the regimes' response to this electoral challenge: (1) the centrality of the elected institution to authoritarian survival; (2) the availability of alternative electioneering tools; and (3) the anticipated response of the international community. The article concludes by suggesting that in order to understand better when and how states deploy violence in elections, we need to focus on a more complex set of factors rather than simply on the electoral potency of key opposition challengers or the authoritarian nature of the state