Quality of Service System Approximation in IP Networks

This paper is sponsored by the Ministry of Education and Research of the Republic of Bulgaria in the framework of project No 105 “Multimedia Packet Switching Networks Planning with Quality of Service and Traffic Management”.This paper presents Quality of Service analyses in wired and wireless IP networks based on the three popular techniques – RSVP, IntServ, and DiffServ. The analyses are based on a quick approximation schema of the traffic system with static and dynamic changes of the system bounds. We offer a simulation approach where a typical leaky bucket model is ap- proximated with a G/D/1/k traffic system with flexible bounds in waiting time, loss and priority. The approach is applied for two cascaded leaky buckets. The derived traffic system is programmed in C++. The simula- tion model is flexible to the dynamic traffic changes and priorities. Student criterion is applied in the simulation program to prove results. The results of the simulation demonstrate the viability of the proposed solution and its applicability for fast system reconfiguration in dynamic environmental circumstances. The simulated services cover a typical range of types of traffic sources like VoIP, LAN emulation and transaction exchange

VoIP Traffic Shaping Analyses in Metropolitan Area Networks

This paper represents VoIP shaping analyses in devices that apply the three Quality of Service techniques – IntServ, DiffServ and RSVP. The results show queue management and packet stream shaping based on simulation of the three mostly demanded services – VoIP, LAN emulation and transaction exchange. Special attention is paid to the VoIP as the most demanding service for real time communication

Evaluation of Pareto/D/1/k Queue by Simulation

The finding that Pareto distributions are adequate to model Internet packet interarrival times has motivated the proposal of methods to evaluate steady-state performance measures of Pareto/D/1/k queues. Some limited analytical derivation for queue models has been proposed in the literature, but their solutions are often of a great mathematical challenge. To overcome such limitations, simulation tools that can deal with general queueing system must be developed. Despite certain limitations, simulation algorithms provide a mechanism to obtain insight and good numerical approximation to parameters of queues. In this work, we give an overview of some of these methods and compare them with our simulation approach, which are suited to solve queues with Generalized-Pareto interarrival time distributions. The paper discusses the properties and use of the Pareto distribution. We propose a real time trace simulation model for estimating the steady-state probability showing the tail-raising effect, loss probability, delay of the Pareto/D/1/k queue and make a comparison with M/D/1/k. The background on Internet traffic will help to do the evaluation correctly. This model can be used to study the long- tailed queueing systems. We close the paper with some general comments and offer thoughts about future work

Ethnoterritorial and etnocultural identity of komi-permyaks’ in nicknames of groups

В статье рассматриваются типы прозвищ коми-пермяков, их значение и происхождение, проводится анализ отношения прозвищ к этнической, территориальной, языковой и культурной идентификации отдельных групп народа.The article describes the types of nicknames of the Komi-Permyaks’, their origin and meaning. The author analyzes, how nicknames relate to ethnic, territorial, linguistic and cultural identity of individual groups of people.Статья выполнена в рамках гранта РГНФ № 12-11-59002

Smoking in asthma is associated with elevated levels of corticosteroid resistant sputum cytokines—an exploratory study

<p>Background: Current cigarette smoking is associated with reduced acute responses to corticosteroids and worse clinical outcomes in stable chronic asthma. The mechanism by which current smoking promotes this altered behavior is currently unclear. Whilst cytokines can induce corticosteroid insensitivity in-vitro, how current and former smoking affects airway cytokine concentrations and their responses to oral corticosteroids in stable chronic asthma is unclear.</p> <p>Objectives: To examine blood and sputum cytokine concentrations in never, ex and current smokers with asthma before and after oral corticosteroids.</p> <p>Methods: Exploratory study utilizing two weeks of oral dexamethasone (equivalent to 40 mg/day prednisolone) in 22 current, 21 never and 10 ex-smokers with asthma. Induced sputum supernatant and plasma was obtained before and after oral dexamethasone. 25 cytokines were measured by multiplex microbead system (Invitrogen, UK) on a Luminex platform.</p> <p>Results: Smokers with asthma had elevated sputum cytokine interleukin (IL) -6, -7, and -12 concentrations compared to never smokers with asthma. Few sputum cytokine concentrations changed in response to dexamethasone IL-17 and IFNα increased in smokers, CCL4 increased in never smokers and CCL5 and CXCL10 reduced in ex-smokers with asthma. Ex-smokers with asthma appeared to have evidence of an ongoing corticosteroid resistant elevation of cytokines despite smoking cessation. Several plasma cytokines were lower in smokers wi</p> <p>Conclusion: Cigarette smoking in asthma is associated with a corticosteroid insensitive increase in multiple airway cytokines. Distinct airway cytokine profiles are present in current smokers and never smokers with asthma and could provide an explanatory mechanism for the altered clinical behavior observed in smokers with asthma.</p&gt

The effect of selected genetic variants, age, sex and training methods on physical activity, capability and trainability

The main objectives of this thesis were to investigate the role of selected genetic variants on physical activity (PA), capacity and trainability in homogenous cohorts from South-Eastern Norway. Two of the cohorts (Papers I and II) represented the general population, and the third consisted of well-trained cross-country skiers (Paper III). We wanted also to investigate how age and sex influence the response to maximal strength training (MST) and performance adaptations in cross-country skiing. In Paper I, three polymorphisms were investigated (ACTN3 R577X, ACE I/D and uVNTR MAOA). Questionnaires were used to divide individuals (n=831) with the mean age (± SD) 55.5 ± 3.8 years (yrs) into groups with either low/medium (LMPA) or high PA (HPA) levels. We investigated the associations between the PA levels and the polymorphisms as well as with several socio-economic variables. We found 10% fewer ACTN3 R577X X allele carriers in the HPA group compared to the LMPA group (p<0.01). Education and previous participation in sports or outdoor activities were positively associated with the PA level, and females reported higher PA levels than males (p<0.01) In Paper II, we genotyped three polymorphisms (ACTN3 R577X, ACE I/D and PPARGC1A rs8192678). 49 subjects (males and females aged 20-76 yrs) completed a MST intervention in leg-press. For 8 weeks subjects trained three sessions/week with each session consisting of 4 · 4 repetitions at ~85-90% of one-repetition maximum (1RM) intensity. At pre- and post-tests, 1RM was tested. We found an average 24% increase in 1RM (p<0.01) independent of age, sex and, surprisingly, training status. Carriers of the PPARGC1A rs8192678 T allele were 15% stronger at baseline (sex- and age-corrected 1RM) compared to individuals with CC genotype (p<0.05). The C allele carriers exhibited 34.2% larger improvements in 1RM (%) than homozygotes for the T allele (p<0.05). A trend was observed towards improved response to MST among the individuals with the ACTN3 R577X RR genotype compared to the XX (30% vs. 19%). In Paper III, seven polymorphisms were investigated (ACTN3 R577X, ACE I/D, ACSL1 rs6552828, IL6 rs1474347, PPARA rs4253778, PPARG rs1801282 and PPARGC1A rs8192678). The study was a 6-month observational study (May to October) based on a cohort of well-trained cross-country skiers (n=29; 16-48 yrs). A number of physiological tests were performed prior (Pre-test), half-way (Post1) and after (Post 2) the study period. Throughout the study, participants maintained and reported their training habits. We found several associations between several of the genetic variants and various physiological/performance variables. For instance, ACTN3 R577X X allele carriers exhibited better DP-VO2max (55.4 vs. 59.4 mL-1·kg·min-1; p<0.05) compared to the RR genotype. Individuals with the XX genotype had, however, poorer work economy than the R allele carriers (0.820 vs. 0.765 mL-1·kg-0.67·m; p<0.05). In regard to other variables, we found a significant effect of age and sex on TTDP (p < 0.01), DP-VO2peak (p < 0.01), CDP (p < 0.05), MAS (p < 0.01), LTv (p < 0.01), 1RM half squat (p < 0.01) and 1RM pull-down (p < 0.01). Sex had also an impact on RUN-VO2max (p < 0.01). The total training volume consisted of ~90% low-intensity training and 5% moderate and high-intensity training, each (range: 357.5 - 1056.8 min/week). During the study, there was a significant increase in the total volume and ski-specific training (p < 0.05), but the intensity distribution remained the same. We did not observe any improvements in either physiological/performance variables for the whole cohort or training progression/adaptation between age groups or sexes during the 6-month period. All in all, our results point towards a potential role of the investigated polymorphisms on the complex traits investigated, i.e. PA levels, maximal strength and endurance performance. Also, for all the genes, the allele frequencies were similar to those reported previously in other European populations. Another important observation was that, although age and sex had an effect on both strength and endurance performance, these factors appeared not to affect the adaptability to maximal strength training or endurance training. Training modality was shown to be highly important, as all participants of the leg-press study (Paper II) improved their maximal strength in response to the MST. In the cross-country study (Paper III), however, no significant changes in endurance parameters were observed during the 6-month study period. Although the participants increased their total training volume, they maintained the same training intensity.publishedVersio

ACE I/D and ACTN3 R577X polymorphisms in the Norwegian population:Do ACE I/D and ACTN3 R577X polymorphisms influence self-reported physical activity levels?

Physical inactivity is a global challenge as physical activity (PA) levels are lower than ever before in human history, and burden of non-communicable diseases continue to increase worldwide. PA is a complex behaviour, and unlike earlier beliefs that environmental factors are main contributor to PA behaviour, genetic factors are receiving increasingly more attention. It is likely that there are many genes, each with only small effect size, influencing the PA levels. These, in turn, interact with other biological and environmental factors to determine activity level of an individual. Genes that favour higher physical fitness have likely a more indirect contribution to PA behaviour. Many potential candidate genes, influencing PA directly and indirectly, have been discovered. Despite many studies on the subject, results are still inconsistent, at least partly due to poor study design. ACE and ACTN3 genes are the most widely investigated in field of exercise genomics. Main focus of many studies is the effect these genes have on athlete sprint and endurance performance. However, increasing number of studies are directed towards the potential effects in the general public. ACE insertion/deletion (I/D) and ACTN3 R577X polymorphisms are of special interest. I-allele of the ACE gene, and X-allele for the ACTN3 gene has been generally associated with improved endurance, while D-allele and R-allele for the ACE and ACTN3 genes, respectively, has been associated with sprint and power related phenotypes. Both polymorphisms are also potential candidate genes for influencing PA levels. Frequency of the different alleles for the ACE I/D and ACTN3 R577X polymorphisms demonstrates a large variation in different population. The present study found that approximately 24% of the Norwegian subjects were homozygous for either D or I-allele for the ACE I/D polymorphism. Around 53% were heterozygous. For the ACTN3 R577X polymorphism, the frequencies were approximately 31%, 49%, and 21% for RR, RX and XX genotype, respectively. Genotype frequencies for both genes did not deviate from HardyWeinberg Equilibrium, and were similar to what had previously been found in other Caucasian populations. Female subjects showed significantly higher self-reported PA levels compared to male subjects. This corresponds well to other studies on the Norwegian population. There was no association between the two genes and self-reported PA levels in the study population of the present study. It is likely that other than ACE and ACTN3 genes influence levels of selfreported PA in the Norwegian population.Published versio

The Endogenous Th17 Response in NO<inf>2</inf>-Promoted Allergic Airway Disease Is Dispensable for Airway Hyperresponsiveness and Distinct from Th17 Adoptive Transfer

Severe, glucocorticoid-resistant asthma comprises 5-7% of patients with asthma. IL-17 is a biomarker of severe asthma, and the adoptive transfer of Th17 cells in mice is sufficient to induce glucocorticoid-resistant allergic airway disease. Nitrogen dioxide (NO2) is an environmental toxin that correlates with asthma severity, exacerbation, and risk of adverse outcomes. Mice that are allergically sensitized to the antigen ovalbumin by exposure to NO2 exhibit a mixed Th2/Th17 adaptive immune response and eosinophil and neutrophil recruitment to the airway following antigen challenge, a phenotype reminiscent of severe clinical asthma. Because IL-1 receptor (IL-1R) signaling is critical in the generation of the Th17 response in vivo, we hypothesized that the IL-1R/Th17 axis contributes to pulmonary inflammation and airway hyperresponsiveness (AHR) in NO2-promoted allergic airway disease and manifests in glucocorticoid-resistant cytokine production. IL-17A neutralization at the time of antigen challenge or genetic deficiency in IL-1R resulted in decreased neutrophil recruitment to the airway following antigen challenge but did not protect against the development of AHR. Instead, IL-1R-/- mice developed exacerbated AHR compared to WT mice. Lung cells from NO2-allergically inflamed mice that were treated in vitro with dexamethasone (Dex) during antigen restimulation exhibited reduced Th17 cytokine production, whereas Th17 cytokine production by lung cells from recipient mice of in vitro Th17-polarized OTII T-cells was resistant to Dex. These results demonstrate that the IL-1R/Th17 axis does not contribute to AHR development in NO2-promoted allergic airway disease, that Th17 adoptive transfer does not necessarily reflect an endogenously-generated Th17 response, and that functions of Th17 responses are contingent on the experimental conditions in which they are generated. © 2013 Martin et al