Peer Review—The Newcomers' Perspective

The World Academy of Young Scientists argue that double blind peer-review will generate a better perception of fairness and equality in global scientific funding and publishin

LayeredCast -A Hybrid Peer-to-Peer Live Layered Video Streaming Protocol

Abstract-Peer-to-Peer overlay networks are an attractive foundation for video streaming. However, live Peer-to-Peer media streaming systems face many challenges such as bandwidth heterogeneity, node churn, and selfish nodes. Although many tree based and mesh based streaming protocols have been proposed, each has its own drawbacks such as unreliability and unfairness in tree based and long startup delay and complex scheduling in mesh based protocols. In this paper, we propose a new video streaming protocol called LayeredCast main features of which are: 1) Hybrid: Drawbacks of the simple approaches are compensated using a hybrid of mesh and tree overlays. 2) Layered Video: Provides an adaptive scheme to enhance the video quality using a layered video codec for heterogeneous clients. 3) QoS: LayeredCast scheduling aims at moving complexity of Multi-Service network core to the network clients application layer, thus providing better QoS over simple regular networks. LayeredCast's tree network pushes the base layer to all peers while the enhancement layers and missing base layer segments are pulled over a mesh network by peers with extra bandwidth using a new data-driven scheduling scheme. We have evaluated the performance of LayeredCast on an innovative simulation framework. Simulation results verify better performance of LayeredCast in term of decodable video frames over CoolStreaming, especially when network resources are limited

The fungus Neurospora crassa displays telomeric silencing mediated by multiple sirtuins and by methylation of histone H3 lysine 9

<p>Abstract</p> <p>Background</p> <p>Silencing of genes inserted near telomeres provides a model to investigate the function of heterochromatin. We initiated a study of telomeric silencing in <it>Neurospora crassa</it>, a fungus that sports DNA methylation, unlike most other organisms in which telomeric silencing has been characterized.</p> <p>Results</p> <p>The selectable marker, <it>hph</it>, was inserted at the subtelomere of Linkage Group VR in an <it>nst-1 </it>(n<it>eurospora </it>s<it>ir </it>t<it>wo</it>-1) mutant and was silenced when <it>nst-1 </it>function was restored. We show that NST-1 is an H4-specific histone deacetylase. A second marker, <it>bar</it>, tested at two other subtelomeres, was similarly sensitive to <it>nst-1 </it>function. Mutation of three additional SIR2 homologues, <it>nst-2</it>, <it>nst-3 </it>and <it>nst-5</it>, partially relieved silencing. Two genes showed stronger effects: <it>dim-5</it>, which encodes a histone H3 K9 methyltransferase and <it>hpo</it>, which encodes heterochromatin protein-1. Subtelomeres showed variable, but generally low, levels of DNA methylation. Elimination of DNA methylation caused partial derepression of one telomeric marker. Characterization of histone modifications at subtelomeric regions revealed H3 trimethyl-K9, H3 trimethyl-K27, and H4 trimethyl-K20 enrichment. These modifications were slightly reduced when telomeric silencing was compromised. In contrast, acetylation of histones H3 and H4 increased.</p> <p>Conclusion</p> <p>We demonstrate the presence of telomeric silencing in Neurospora and show a dependence on histone deacetylases and methylation of histone H3 lysine 9. Our studies also reveal silencing functions for DIM-5 and HP1 that appear independent of their role in <it>de novo </it>DNA methylation.</p

Evaluation growths and survival indexes of vaccinated Litopenaeus vannamei against white spot virus syndrome

Nowadays, white spot virus disease is serious threat for breeding and culture industry of shrimp. In this study was increasing resistance of shrimp against white spot virus by using modern methods such as shrimp vaccination with inactivated viruses and recombinant proteins. The aim of this study were determine the growth and survival rates vaccinated and non-vaccinated of Litopenaeus vannamei (5 to 15 and 12 to 26 day), that were challenged with white spot virus in 40 and 60 day rearing. This study consisted two separate groups were vaccinated and non-vaccinated with 11 treatments experimental and each of replicate was stocked 1000 pieces by post larva of 5 to15 and 12 to 26 day. After vaccination, two groups of post larvae exposed to the white spot virus at 40 and 60 day, one groups no exposure to the virus. Samplings were randomly of shrimp in 40, 60 and 80 days 10 pieces each of treatment experimental and measured mean of weight and length. Also, number of deaths was recorded at morning and evening daily and calculated survival rate at the end of study. The results showed growth rate of post larvae vaccinated (5 to15 day) which exposed to white spot virus at 40 and 60 was significantly lower than non-vaccinated of post larval, while the growth rate of post larval exposed to virus in 60 day was significantly increased. On the other hand, growth rate of post larval vaccination (12 to 26 day) exposed to virus in 60 day compared with post larval vaccination (5 to 15 and 12 to 26) exposed to virus in 40 and 60 days was significantly increased. Hence, growth rate was significantly increased in post larval vaccinated (5 to 15 and 12 to 26) which non-exposed to virus. Although the survival rate was post larval vaccinated (12 to 26 days) exposed to virus Post larvae in 60 day higher than post larval were exposed to virus in 40 and 60, but no significant differences were observed. However, relative mortality of post larval vaccination in 12 to 26 day compared with post larval vaccination in 5 to 15 days exposed to virus were significantly lower. Considering growth and survival index was improved of post larval vaccination can be concluded that the optimum age for vaccination against white spot virus of L.vannamei was 12 to 26 day

Conformal fields in prostate radiotherapy: A comparison between measurement, calculation and simulation

Aims: The objective of this study is to evaluate the accuracy of a treatment planning system (TPS) for calculating the dose distribution parameters in conformal fields (CF). Dosimetric parameters of CF′s were compared between measurement, Monte Carlo simulation (MCNP4C) and TPS calculation. Materials and Methods: Field analyzer water phantom was used for obtaining percentage depth dose (PDD) curves and beam profiles (BP) of different conformal fields. MCNP4C was used to model conformal fields dose specification factors and head of linear accelerator varian model 2100C/D. Results: Results showed that the distance to agreement (DTA) and dose difference (DD) of our findings were well within the acceptance criteria of 3 mm and 3%, respectively. Conclusions: According to this study it can be revealed that TPS using equivalent tissue air ratio calculation method is still convenient for dose prediction in non small conformal fields normally used in prostate radiotherapy. It was also showed that, since there is a close correlation with Monte Carlo simulation, measurements and TPS, Monte Carlo can be further confirmed for implementation and calculation dose distribution in non standard and complex conformal irradiation field for treatment planning systems

Two RNAi complexes, RITS and RDRC, physically interact and localize to noncoding centromeric RNAs.

International audienceRNAi-mediated heterochromatin assembly in fission yeast requires the RNA-induced transcriptional silencing (RITS) complex and a putative RNA-directed RNA polymerase (Rdp1). Here we show that Rdp1 is associated with two conserved proteins, Hrr1, an RNA helicase, and Cid12, a member of the polyA polymerase family, in a complex that has RNA-directed RNA polymerase activity (RDRC, RNA-directed RNA polymerase complex). RDRC physically interacts with RITS in a manner that requires the Dicer ribonuclease (Dcr1) and the Clr4 histone methyltransferase. Moreover, both complexes are localized to the nucleus and associate with noncoding centromeric RNAs in a Dcr1-dependent manner. In cells lacking Rdp1, Hrr1, or Cid12, RITS complexes are devoid of siRNAs and fail to localize to centromeric DNA repeats to initiate heterochromatin assembly. These findings reveal a physical and functional link between Rdp1 and RITS and suggest that noncoding RNAs provide a platform for siRNA-dependent localization of RNAi complexes to specific chromosome regions