42 research outputs found

    Interactions between WLAN networks

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    Tato práce se zabývá vzájemným ovlivňováním WLAN sítí. Vysvětluje historii a následný vývoj bezdrátových technologií a poté se zaměřuje na současné WLAN sítě. Popisuje problematiku rušení ve WLAN sítích a parametry, které nedílnou součástí přispívají k vzájemnému rušení. Součástí práce je vypracování dvou laboratorních úloh. První úloha je realizována v programu Riverbed, ve kterém je sestavena topologie se třemi stejnými WLAN routery. Po otestování WLAN routerů je zobrazen graf popisující rušení v pásmu 2,4 GHz, kterého je dosaženo vhodným zvolením frekvenčního pásma, vysílacího výkonu a kanálu. Druhá laboratorní úloha je realizována v programu Iperf3, který je nainstalovaný na třech Raspberry Pi (RPi Zero, RPi 3 a RPi 4). Zahlcení sítě je docíleno pomocí skriptu wifijammer, který je nainstalován na RPi 4. V této druhé laboratorní úloze byly nejdříve ověřeny parametry přenosu a pomocí skriptu wifijammer byla odmítnuta služba. Pro testování druhé laboratorní úlohy byly zvoleny standardy IEEE 802.11b a IEEE 802.11n s ve frekvenčním pásmu 2,4 GHz. Testování probíhalo na routrech Mercusys, Netis, Tp-Link a Asus. Výsledky z testovacích scénářů byly přehledně zpracovány formou grafů.This bachelor thesis deals with the possible interferences caused by the parallel running WLAN networks. It explains the history and subsequent development of wireless technologies and then focuses on current WLAN networks. It describes the problem of interference in WLAN networks and parameters that contribute to mutual interference. Practical part of this thesis consists of two laboratory exercises. The first task is implemented in the Riverbed program, in which a topology with three identical WLAN routers is assembled. After testing the WLAN routers, a graph describing the interference in the 2.4 GHz band is displayed, which is achieved by a suitable choice of frequency band, transmission power and channel. The second laboratory task is implemented utilizing the Iperf3 program, which is installed on three Raspberry Pi´s (RPi Zero, RPi 3, and RPi 4). Network congestion is achieved using the wifijammer script, which is installed on RPi 4. In this second laboratory task, the transmission parameters were first verified and the service was denied using the wifijammer script. For evaluation of the second laboratory task, the IEEE 802.11b and IEEE 802.11n utilizing the frequency band 2,4 GHz were chosen. For testing, the following routers were used: Mercusys, Netis, Tp-Link and Asus routers. Once the measurements were over, all the data was processed and included as charts.

    Comparison of Terbutryn Acute Toxicity to Danio rerio and Poecilia reticulata

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    Abstract The aim of the present study was to determine and compare acute toxicity of terbutryn in Danio rerio and Poecilia reticulata, and in two different developmental stages of D. rerio -embryonic and juvenile. Acute toxicity tests were performed according to OECD methodology. The LC50 values were assessed by probit analysis using EKO-TOX 5.2 programme. The 96hLC50 terbutryn mean value of 5 tests was 2.85 ± 0

    Cell-based and multi-omics profiling reveals dynamic metabolic repurposing of mitochondria to drive developmental progression of Trypanosoma brucei

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    Mitochondrial metabolic remodeling is a hallmark of the Trypanosoma brucei digenetic life cycle because the insect stage utilizes a cost-effective oxidative phosphorylation (OxPhos) to generate ATP, while bloodstream cells switch to aerobic glycolysis. Due to difficulties in acquiring enough parasites from the tsetse fly vector, the dynamics of the parasite’s metabolic rewiring in the vector have remained obscure. Here, we took advantage of in vitro–induced differentiation to follow changes at the RNA, protein, and metabolite levels. This multi-omics and cell-based profiling showed an immediate redirection of electron flow from the cytochrome-mediated pathway to an alternative oxidase (AOX), an increase in proline consumption, elevated activity of complex II, and certain tricarboxylic acid (TCA) cycle enzymes, which led to mitochondrial membrane hyperpolarization and increased reactive oxygen species (ROS) levels. Interestingly, these ROS molecules appear to act as signaling molecules driving developmental progression because ectopic expression of catalase, a ROS scavenger, halted the in vitro–induced differentiation. Our results provide insights into the mechanisms of the parasite’s mitochondrial rewiring and reinforce the emerging concept that mitochondria act as signaling organelles through release of ROS to drive cellular differentiation

    Molecular and cytological characterization of the global Musa germplasm collection provides insights into the treasure of banana diversity

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    © 2016, The Author(s). Bananas (Musa spp.) are one of the main fruit crops grown worldwide. With the annual production reaching 144 million tons, their production represents an important contribution to the economies of many countries in Asia, Africa, Latin-America and Pacific Islands. Most importantly, bananas are a staple food for millions of people living in the tropics. Unfortunately, sustainable banana production is endangered by various diseases and pests, and the breeding for resistant cultivars relies on a far too small base of genetic variation. Greater diversity needs to be incorporated in breeding, especially of wild species. Such work requires a large and thoroughly characterized germplasm collection, which also is a safe depository of genetic diversity. The largest ex situ Musa germplasm collection is kept at the International Transit Centre (ITC) in Leuven (Belgium) and currently comprises over 1500 accessions. This report summarizes the results of systematic cytological and molecular characterization of the Musa ITC collection. By December 2015, 630 accessions have been genotyped. The SSR markers confirmed the previous morphological based classification for 84% of ITC accessions analyzed. The remaining 16% of the genotyped entries may need field verification by taxonomist to decide if the unexpected classification by SSR genotyping was correct. The ploidy level estimation complements the molecular data. The genotyping continues for the entire ITC collection, including newly introduced accessions, to assure that the genotype of each accession is known in the largest global Musa gene bank. Open Access ispartof: Biodiversity and Conservation vol:26 issue:4 pages:801-824 status: publishe

    Interactions between WLAN networks

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    This bachelor thesis deals with the possible interferences caused by the parallel running WLAN networks. It explains the history and subsequent development of wireless technologies and then focuses on current WLAN networks. It describes the problem of interference in WLAN networks and parameters that contribute to mutual interference. Practical part of this thesis consists of two laboratory exercises. The first task is implemented in the Riverbed program, in which a topology with three identical WLAN routers is assembled. After testing the WLAN routers, a graph describing the interference in the 2.4 GHz band is displayed, which is achieved by a suitable choice of frequency band, transmission power and channel. The second laboratory task is implemented utilizing the Iperf3 program, which is installed on three Raspberry Pi´s (RPi Zero, RPi 3, and RPi 4). Network congestion is achieved using the wifijammer script, which is installed on RPi 4. In this second laboratory task, the transmission parameters were first verified and the service was denied using the wifijammer script. For evaluation of the second laboratory task, the IEEE 802.11b and IEEE 802.11n utilizing the frequency band 2,4 GHz were chosen. For testing, the following routers were used: Mercusys, Netis, Tp-Link and Asus routers. Once the measurements were over, all the data was processed and included as charts
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