Cylindrical solutions in braneworld gravity

In this article we investigate exact cylindrically symmetric solutions to the modified Einstein field equations in the brane world gravity scenarios. It is shown that for the special choice of the equation of state $2U+P=0$ for the dark energy and dark pressure, the solutions found could be considered formally as solutions of the Einstein-Maxwell equations in 4-D general relativity.Comment: 12 pages, RevTex format, typos corrected and references added. Accepted for publication in PR

Quantum gravitational optics in the field of a gravitomagnetic monopole

Vacuum polarization in QED in a background gravitational field induces interactions which {\it effectively} modify the classical picture of light rays as the null geodesics of spacetime. After a short introduction on the main aspects of the quantum gravitational optics, as a nontrivial example, we study this effect in the background of NUT space characterizing the spacetime of a spherical mass endowed with a gravitomagnetic monopole charge, the so called NUT factor.Comment: 9 pages, title changed and the text abridged for publication in the Journal of Physics: Conference serie

New bounds on the signed total domination number of graphs

In this paper, we study the signed total domination number in graphs and present new sharp lower and upper bounds for this parameter. For example by making use of the classic theorem of Turan, we present a sharp lower bound on this parameter for graphs with no complete graph of order r+1 as a subgraph. Also, we prove that n-2(s-s') is an upper bound on the signed total domination number of any tree of order n with s support vertices and s' support vertives of degree two. Moreover, we characterize all trees attainig this bound.Comment: This paper contains 11 pages and one figur

Detecting Singleton Review Spammers Using Semantic Similarity

Online reviews have increasingly become a very important resource for consumers when making purchases. Though it is becoming more and more difficult for people to make well-informed buying decisions without being deceived by fake reviews. Prior works on the opinion spam problem mostly considered classifying fake reviews using behavioral user patterns. They focused on prolific users who write more than a couple of reviews, discarding one-time reviewers. The number of singleton reviewers however is expected to be high for many review websites. While behavioral patterns are effective when dealing with elite users, for one-time reviewers, the review text needs to be exploited. In this paper we tackle the problem of detecting fake reviews written by the same person using multiple names, posting each review under a different name. We propose two methods to detect similar reviews and show the results generally outperform the vectorial similarity measures used in prior works. The first method extends the semantic similarity between words to the reviews level. The second method is based on topic modeling and exploits the similarity of the reviews topic distributions using two models: bag-of-words and bag-of-opinion-phrases. The experiments were conducted on reviews from three different datasets: Yelp (57K reviews), Trustpilot (9K reviews) and Ott dataset (800 reviews).Comment: 6 pages, WWW 201

Evaluating high risks in large-scale projects using an extended VIKOR method under a fuzzy environment

The complexity of large-scale projects has led to numerous risks in their life cycle. This paper presents a new risk evaluation approach in order to rank the high risks in large-scale projects and improve the performance of these projects. It is based on the fuzzy set theory that is an effective tool to handle uncertainty. It is also based on an extended VIKOR method that is one of the well-known multiple criteria decision-making (MCDM) methods. The proposed decision-making approach integrates knowledge and experience acquired from professional experts, since they perform the risk identification and also the subjective judgments of the performance rating for high risks in terms of conflicting criteria, including probability, impact, quickness of reaction toward risk, event measure quantity and event capability criteria. The most notable difference of the proposed VIKOR method with its traditional version is just the use of fuzzy decision-matrix data to calculate the ranking index without the need to ask the experts. Finally, the proposed approach is illustrated with a real-case study in an Iranian power plant project, and the associated results are compared with two well-known decision-making methods under a fuzzy environment

Study on nanoparticles of Aloe vera extract on growth performance, survival rate and body composition in Siberian sturgeon (Acipenser baerii)

The application of nanotechnology in drug delivery and a variety of supplements is very impressive. In this regard, the use of this knowledge can be effective in the performance of medicinal plants in aquaculture. In the present study Aloe vera was extracted and its nanoparticles were produced. Three levels of Aloe vera nanoparticles in Siberian sturgeon (Acipenser baerii) were evaluated for the effects on growth performance, survival rate and body composition. A total of 360 Siberian sturgeon (A. baerii) with an average of 10.95 ± 0.04 (g) randomly divided into four treatment groups with three replicates each. The treatment groups were fed with diets that included 0% (control), 0.5, 1 and 1.5% of Aloe vera nanoparticles for 60 days. Weight gain, initial body weight, condition factor, feed conversion ratio, specific growth rate, protein efficiency ratio, survival rate, and body composition (protein, lipid, carbohydrate, ash and moisture) were measured and compared among the fish in the different groups. The results showed that growth indices of fish fed the Aloe vera nanoparticles were higher than the control diet, so that the difference between the control group and 1% Aloe vera nanoparticles was more than that in other treatments. In each of the body composition parameters, no significant differences were observed among the treatments and control groups (p>0.05). Considering that there are no significant differences in results between 1% and 1.5% Aloe vera nanoparticles, the results showed that adding 1% Aloe vera nanoparticles to the fish diet improves the growth factors of Siberian sturgeon

Nurses' Requirements for Relief and Casualty Support in Disasters: A Qualitative Study

Background: Nurses are among the most important groups engaged in casualty support, regardless of the cause, and they are one of the largest care groups involved in disasters. Consequently, these workers should gain proper support and skills to enable effective, timely, responsible and ethical emergency responses. Objectives: In this study, we investigated the needs of nurses for proper casualty support in disasters, to facilitate better planning for disaster management. Materials and Methods: This was a qualitative content analysis study. Interviews were performed with 23 nurses, at educational hospitals and the Faculty of Nursing at Kerman Medical University, who had a minimum of five years working experience and assisted in an earthquake disaster. Intensity and snowball sampling were performed. Data was collected through semi-structured interviews. Interviews were transcribed and coded into main themes and subthemes. Results: Four major themes emerged from the data; 1) psychological support, 2) appropriate clinical skills education, 3) appropriate disaster management, supervision and programming, and 4) the establishment of ready for action groups and emergency sites. The participants’ comments highlighted the necessity of training nurses for special skills including emotion management, triage and crush syndrome, and to support nurses' families, provide security, and act according to predefined programs in disasters. Conclusions: There are a wide range of requirements for disaster aid. Proper aid worker selection, frequent and continuous administration of workshops and drills, and cooperation and alignment of different governmental and private organizations are among the suggested initiatives