Exact Analysis of Offset-based Service Differentiation in Single-channel Multi-class OBS

Cataloged from PDF version of article.We study a multi-class optical burst switching (OBS) node using the horizon reservation scheme. Multiple traffic classes are differentiated using different offset times per class. Assuming Poisson burst arrivals and phase-type distributed burst lengths, we exactly solve for per-class blocking probabilities using the well-known theory of feedback Markov fluid queues

A performance evaluation framework of a rate-controlled MPEG video transmission over UMTS networks

UMTS is designed to offer high bandwidth radio access with QoS assurances for multimedia communications. In particular, real-time video communications services are expected to become a successful experience under UMTS networks. In this context, a video transmission service can be designed over the basis that UMTS can provide either a constant bit rate data channel or a dynamic variable bit rate data channel adapted to load conditions. In this latter approach, which is more efficient for both the user and the service provider, multimedia sources have to be timely designed in order to adapt their output rate to the instantaneous allowed channel rate. The target of this paper is to define an analytical model of adaptive real-time video sources in a UMTS network where system resources are dynamically shared among active users. © 2007 IEEE

Induction of micronuclei in Chalcalburnus tarichi(Pallas, 1811) exposed to sub-lethal concentrations of methyl parathion

The micronucleus assay (MNT) is a mutagenicity test system for determining pollution and chemicals causing changes in DNA fragments, such as micronuclei (MN) in the cytoplasm of interphase cells. Damage caused in the DNA by genotoxic pollutants is the first consequence occurring in the aquatic organisms. The MNT in fish erythrocytes has increasingly been used to detect the genotoxic effects of environmental mutagens, and its frequency is considered to reflect the genotoxic damage to cells, mainly the chromosomes. In this study, the genotoxic effects of methyl parathion (MP), one of the most commonly used pesticides in Lake Van Basin, on Chalcalburnus tarichi (Pallas, 1811), which is an economically important endemic species in the basin, were investigated. The experiment was carried out over a period of 30 days using an in vivo method on samples of peripheral erythrocytes of C. tarichi taken at sampling times. The fish were exposed to increasing concentrations of MP (1.47, 2.1, 3.0, 4.28 and 6.11 mg L-1) under semi-static conditions in the laboratory. The increase in micronucleus frequency was significant as well as altered cells' frequencies. Thus, it was attempted to determine whether MP affected the erythrocytes of C. tarichi at the level of DNA by means of the MN test. According to the results of the present study, the highest level of frequency of MN was found at 6.11 mg L-1. In conclusion, this study indicates that the MN test gives sensitive results in determining the genotoxicity of pesticides, and thus, it might be used as a standard method for regularly monitoring the genotoxic effects of pesticides. © by PSP

Hematological and biochemical response in the blood of Alburnus tarichi (Actinopterygii: Cypriniformes: Cyprinidae) exposed to tebuconazole

Background. Lake Van, the second-largest soda lake in the world, has a pH 9.8 value. A fish, locally known as Van fish, Alburnus tarichi (Güldenstädt, 1814), is an endemic fish of Lake Van and known also as pearl mullet, tarek, or Van bleak. Tebuconazole is a widely used pesticide around Lake Van. In this study, we will focus on the effects of tebuconazole on Van fish blood to provide critical information on the environmental risk assessment of pesticides in various aquatic environments. Materials and methods. The Van fish were exposed to tebuconazole for 24, 48, 72, and 96 h at a concentration of 2.5 mg ·L–1. Subsequently, the resulting hematological and biochemical parameters were determined. Results. There was a statistically significant decrease in erythrocytes (RBC), hemoglobin (Hb), and hematocrit (Hct) in the blood parameters (P < 0.05). The levels of serum, aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), urea, and creatine increased significantly (P < 0.05). The serum cortisol level increased significantly at all hours after the administration of tebuconazole (P < 0.05). Conclusion. As a result, toxicity caused by pesticides caused negative changes in the biochemical and hematological values of Van fish. Changes in these parameters have shown that it can be used as a biomarker for toxicity

Small Cell Carcinomas of the Bladder Highly Express Somatostatin Receptor Type 2A: Impact on Prognosis and Treatment--A Multicenter Study of Urooncology Society, Turkey.

Small cell carcinoma (SmCC) is a rare and aggressive neuroendocrine carcinoma of the bladder. Neuroendocrine carcinomas expressing somatostatin receptors (SSTR) in other viscera such as lung, pancreas, and gastrointestinal system respond to therapy with somatostatin analogs. In the present study, expressions of SSTRs 1 to 5 including type 2A are investigated by immunohistochemistry (IHC) and their relationship with clinicopathologic factors was evaluated. Hundred primary bladder SmCC cases were collected from 12 centers in Turkey. Forty-three cases were pure SmCC. Other cases had mostly papillary urothelial carcinoma as a second component. The percentage of the SmCC component ranged from 5% to 100%. SSTR-2A expression was membranous, whereas the other receptors showed cytoplasmic staining. The percentages of positive cases for SSTR-1, SSTR-2A, SSTR-3, SSTR-4, and SSTR-5 were 4% (3/75), 61.4% (54/88), 2.4% (2/84), 24.4% (20/82), and 6.25% (5/80), respectively. The percentage of SmCC component was positively correlated with the percentage of SSTR-2A expression (P=0.003) while negatively correlated with patient age (P=0.032). SSTR-2A expression was correlated with survival as a bad prognostic factor (P=0.018). SSTR-1, SSTR-3, SSTR-4, and SSTR-5 expressions did not show any statistical significance with any parameter. In conclusion, although the limited number of cases with adequate term follow-up, SSTR-2A expression could be a prognostic factor and somatostatin analogs therapeutic candidate for SmCCs of the bladder as these tumors show high percentage of SSTR-2A expression