Viruses and bacteriophages

Many of the enteric viruses which are transmitted from person to person by thefecal-oral route are found in raw and treated wastewater, and because of their persistence under adverse conditions may also be found in slightly polluted waters.There is no routine examination procedure of water and wastewater for entero-viruses,mainly because of the cumbersome isolation techniques, high cost and the need for highly skilled laboratory personnel.Phages are specific to single species of bacteria, are known for many entericbacteria, and are very often used for final identification of enteric pathogenic bacteria.Coliphages are provalent in raw and treated sewage as well as in polluted water, where enteric viruses may also be found.Coliphages were often mentioned as possible viral indicators in polluted water.To be a perfect indicator, they should comply with minimum criteria as follows: (a) they should be present wherever human enteric viruses are present: (b) the coliphage numbers recovered should be equal to or larger than those of enteric viruses recovered: (c) the coliphages should be at least as resistant as enteric viruses to adverse environmental conditions: (d) isolation and quantification of the coliphage should be faster and less expensive than isolation of the enteroviruses.Comparative studies show that the coliphage to enterovirus ratio in wastewater is about 10³:1. Levels of poliovirus 1 (attenuated) to coliphage f2 remained stable for a few months in oxidation pond effluents.f2 coliphage exhibited higher resistance to chlorination than poliovirus 1 (attenuated). When the two strains were kept in water of different quality, f2 survived longer. In addition, all coliphage counts were completed within 24 h. while those of enteroviruses required about a week. Results indicate very strongly that coliphages can be used as viral indicators and this is already the practice in a few European and other countries.     

Flow pattern in horizontal and vertical two phase flow in small diameter pipes

New data on flow pattern transition for gas liquid flow in small diameter tubes (4 to 12 mm) is presented. The experimental results are compared with previously published models for horizontal and vertical flows considered to be valid for medium and large diameter pipes. The effect of surface tension which might be expected to be important in small diameter pipe flow has been found to affect only the stratified-slug transition in horizontal flow. A modification to the model to include this effect is proposed.     

The Photochemistry of Solutions of Eu(III) and Eu(II)

Irradiation in the CT band of Eu³⁺ in aqueous solution, in the presence of scavengers for H atoms, gives rise to formation of Eu²⁺ and evolution of molecular hydrogen. The kinetics of these processes were studied as functions of the concentrations of Eu³⁺ and scavenger, of pH, and of light intensity. The results are interpreted by means of a complex scheme in which an excited Eu²⁺ donates an electron to a proton, the resulting H* initiating a series of dark reactions which lead to evolution of H₂ and oxidation of the scavenger.     

Flooding in inclined pipes — Effect of entrance section

Flooding in countercurrent flow of air and water in inclined tubes has been investigated. Data on flooding inception in the whole range of inclinations have been collected and predictive models for calculating the flooding conditions as a function of the flow rates and pipe inclination were proposed. Special attention is placed on the effect of the liquid injection mode. It has been shown that the porous injection system causes a local disturbance and enhances flooding at relatively shallow inclinations and high liquid flow rates.     

Can You Explain This？ Personality and Willingness to Commit Various Acts of Academic Misconduct

The rapid development of IT has created a problematic situation in higher education by providing individuals with a greater opportunity to engage in academic dishonesty especially in online courses, in contrast to traditional classroom courses. There are various factors that were used in research to explain the phenomenon of academic dishonesty. Among them are personality traits that were found to be effective in explaining unethical behaviors. Therefore, this study explores students＇ personality traits as predictors of academic dishonesty in the context of traditional and distance-learning courses in higher education. Data from 1,365 students enrolled in academic institutes in the U.S.A and Israel were surveyed to assess their personality and their willingness to commit various acts of academic misconduct. The findings indicate that in both countries dishonest behaviors are greater in face-to-face than in online courses. In addition, both American and Israeli students identified with the personality trait of agreeableness showed a negative correlation with academic dishonesty, Furthermore, Israeli students identified with the personality traits of conscientiousness and emotional stability demonstrated a negative correlation with academic dishonesty. In contrast, the personality trait of extraversion among American students was positively correlated with academic misconduct. Implications for further research are discussed.     

Flow pattern transition for downward inclined two phase flow; horizontal to vertical

Data on the flow pattern transition for gas liquid flow in pipes for downward 0–90° inclination was collected. Mathematical models were developed to predict the flow pattern in the whole range of downward inclination.     

Fast Garbling of Circuits Under Standard Assumptions

Protocols for secure computation enable mutually distrustful parties to jointly compute on their private inputs without revealing anything, but the result. Over recent years, secure computation has become practical and considerable effort has been made to make it more and more efficient. A highly important tool in the design of two-party protocols is Yao’s garbled circuit construction (Yao 1986), and multiple optimizations on this primitive have led to performance improvements in orders of magnitude over the last years. However, many of these improvements come at the price of making very strong assumptions on the underlying cryptographic primitives being used (e.g., that AES is secure for related keys, that it is circular-secure, and even that it behaves like a random permutation when keyed with a public fixed key). The justification behind making these strong assumptions has been that otherwise it is not possible to achieve fast garbling and thus fast secure computation. In this paper, we take a step back and examine whether it is really the case that such strong assumptions are needed. We provide new methods for garbling that are secure solely under the assumption that the primitive used (e.g., AES) is a pseudorandom function. Our results show that in many cases, the penalty incurred is not significant, and so a more conservative approach to the assumptions being used can be adopted.     

Efficient Protocols for Set Intersection and Pattern Matching with Security Against Malicious and Covert Adversaries

In this paper, we construct efficient secure protocols for set intersection and pattern matching. Our protocols for secure computing the set intersection functionality are based on secure pseudorandom function evaluations, in contrast to previous protocols that are based on polynomials. In addition to the above, we also use secure pseudorandom function evaluation in order to achieve secure pattern matching. In this case, we utilize specific properties of the Naor–Reingold pseudorandom function in order to achieve high efficiency.