PERFORMANCE EVALUATION OF WiFi WITH AND WITHOUT QoS

Wireless local area networks (WLANs) have been around for a long time but only recently have they become popular. Despite the fact that Wireless LANs have achieved a tremendous amount of growth in recent years, the performance is very poor. Hence, multimedia wireless network QoS support has become one of the most important researches. In order to improve the poor performance of existing system, QoS features and MAC enhancements are needed in the upcoming 802.1 le standard. This project aims to evaluate the performance of Wi-Fi systems with and without QoS, and quantify how well the new enhancement can support applications that require certain QoS guarantees. A thorough research on the IEEE802.11 standards is necessary to the success ofthis project, as well as an immaculate and extensive study on the QoS performance ofthe network. All the studies and evaluation is being done with a simulation using OMNeT++. The project requires knowledge of the WiFi architecture, C++ programming language, setting up simulation of a network in OMNeT++, andthen evaluating theQoS performance

Dietary Mercury Exposure in Male Zebra Finches Does Not Decrease their Attractiveness to Females

Choosing a high-quality mate contributes strongly to increased reproductive success in birds. Female birds assess quality in males, in part, via condition-dependent signals such as male songs and plumage. The production of attractive signals can be disrupted by environmental stressors, however, including environmental toxins. Mercury, a globally-increasing pollutant, is one such toxin. Mercury exposure has been shown to affect song, plumage, bill color, and mating behaviors in male birds, but the effect of these changes on the outcome of female mate choice is unknown. These effects on condition-dependent signals indicate that mercury could potentially alter males’ attractiveness to females, as females use such traits to assess quality of potential mates. We sought to determine if male attractiveness to females is affected by dietary mercury exposure, using zebra finches as our model system. Males were either exposed to dietary mercury (1.2 ppm) or unexposed (0.0 ppm), and then assessed by unexposed females in three types of mate preference trials: song-only phonotaxis trials, that observed female preference for mercury-exposed or unexposed songs; two-choice association preference trials, that observed female preference for mercury-exposed or unexposed males in neighboring cages; and aviary pairing trials, in which females were given the opportunity to pair with either a mercury-exposed male or unexposed male. In phonotaxis trials and association trials, females did not spend more time near songs or males of one treatment over the other. In aviary pairing trials, females were equally likely to pair with males of either treatment. While mercury exposure is known to reduce reproductive output in zebra finches and other birds, our results suggest that females are not incorporating mercury-induced variation in male traits into their mate choice decisions. This raises questions about the future evolution of the avian mate choice system in an environment increasingly affected by toxins, as females experience fitness losses as a result of potentially poor mate choice decisions. If this is the case, then females are likely to respond to this sexual selection pressure by including toxin-mediated trait variation in their quality assessment mechanisms

PERFORMANCE EVALUATION OF WiFi WITH AND WITHOUT QoS

Wireless local area networks (WLANs) have been around for a long time but only recently have they become popular. Despite the fact that Wireless LANs have achieved a tremendous amount of growth in recent years, the performance is very poor. Hence, multimedia wireless network QoS support has become one of the most important researches. In order to improve the poor performance of existing system, QoS features and MAC enhancements are needed in the upcoming 802.1 le standard. This project aims to evaluate the performance of Wi-Fi systems with and without QoS, and quantify how well the new enhancement can support applications that require certain QoS guarantees. A thorough research on the IEEE802.11 standards is necessary to the success ofthis project, as well as an immaculate and extensive study on the QoS performance ofthe network. All the studies and evaluation is being done with a simulation using OMNeT++. The project requires knowledge of the WiFi architecture, C++ programming language, setting up simulation of a network in OMNeT++, andthen evaluating theQoS performance

Robotic work cell for packing canisters

The purpose of this project is to reduce the manufacturing cost of the special order 2500cc truck canisters produced at Rochester Products\u27 Lee Road facility. This was accomplished by designing and developing a robotic work cell to pack the canisters into baskets at the injection mold machine. A literature search was conducted to gain a broader understanding of robotic applications and end-effector design. In developing this cell, the layout of the work cell components was determined, a suitable robot was selected, and an end-effector was designed, built and tested

Alterations in lymphocyte signalling produced by exposure to mercury

The effects of 1 min – 4 hr exposures to mercuric chloride (HgCl2), methyl mercuric chloride (CH3HgCl), p-chloromercuribenzoate (p-CMB) and ethylmercurithiosalicylate (TMS) on cell viability and kinetics of cell death, microtubules, F-actin, CD3 receptor expression, protein tyrosine phosphorylation (PTyr-P), intracellular calcium [Ca2+]i and responses to polarized signals in YAC-1 lymphoma cells were investigated. We hypothesized that immunotoxic effects of HgCl2 (Hg2+) are initiated by global receptor triggering, accompanied by increased protein tyrosine phosphorylation (PTyr-P) and down-regulation of the T-cell receptor (TCR). As a polychloride anion with poor lipid solubility, inorganic Hg2+ may produce effects at the outer cell membrane before significant intracellular accumulation, loss of microtubule integrity (a sensitive target) and activation of cell death through apoptotic pathways. The organomercurial compound p-CMB is likewise thought to penetrate membranes slowly as a result of ionization. In contrast, the highly lipid-soluble organomercurial compounds CH3HgCl and TMS were expected to reduce responses to polarized stimuli only in conjunction with – and not prior to – loss of microtubule integrity and the onset of necrotic cell death. Two general patterns of effects were observed. In HgCl2-treated YAC-1 cells, inhibition of responses to polarized stimuli preceded loss of microtubules and onset of cell death. Effects on polarized stimuli were preceded by a transient Ca2+ signal; however, this Ca2+ signal appeared abortive, accompanied by a paradoxic decrease in PTyr-P and partial down-regulation of CD3 receptors. Responses to polarised stimuli were inhibited prior to extensive loss of microtubule staining, indicating effects preceded cytosolic Hg2+ accumulation. HgCl2 exposure was followed rapidly by necrotic cell death. Similarly, p-CMB-treated YAC-1 cells failed to respond to polarized stimuli before effects on microtubules or loss of viability, and proceeded rapidly to late apoptosis; however, a transient Ca2+ signal and progressive loss of F-actin preceded effects in all other assays and may account for loss of polarized responses. In CH3HgCl- and TMS-treated YAC-1 cells, CD3 receptor expression, [Ca2+] and PTyr-P were increased immediately, along with loss of microtubules. These reductions preceded inhibition of polarized signaling responses and seemed to indicate a general loss of cellular homeostasis not seen in HgCl2- and p-CMB-treated cells; loss of homeostasis did not necessarily produce simultaneous loss of viability, as TMS-treated cells remained viable for 30 min while CH3HgCl-treated cells became apoptotic within 1 min. Nonetheless, the YAC-1 cells proceeded to cell death more slowly, remaining early apoptotic after 4 hr, when almost all HgCl2- and p-CMB-treated cells were necrotic. These findings indicate the two groups of mercury compounds may alter responses to polarized stimuli and induce cell death by distinct pathways, one involving an apparently abortive signal and the other mediated by much more profound disruption of cellular homeostasis. Within the larger patterns there are further differences between the effects produced by each Hg compound, likely reflecting the combined influence of pharmaco–kinetic and –dynamic factors governing access to and interactions with different cellular targets leading to cell death. These distinct targets may in turn be reflected in the different immune effects produced by these compounds in vivo

Nascom System Development Plan: System Description, Capabilities and Plans

The NASA Communications (Nascom) System Development Plan (NSDP), reissued annually, describes the organization of Nascom, how it obtains communication services, its current systems, its relationship with other NASA centers and International Partner Agencies, some major spaceflight projects which generate significant operational communication support requirements, and major Nascom projects in various stages of development or implementation

Risks Associated with Harvesting and Human Consumption of Two Turtle Species in New Jersey

Snapping turtles and diamondback terrapins have unique life characteristics, making their populations’ survivorship heavily dependent upon the turtles that reach sexual maturity, limiting the harvest potential of turtles and making them vulnerable to exploitation. Therefore, this research tests mercury concentrations in diamondback terrapins and snapping turtles to determine if turtle meat should require human consumption advisories, and examines transport of mercury through the snapping turtle food web by testing prey items for mercury burden and mapping food webs using stable isotope composition. Consumption of New Jersey diamondback terrapins and snapping turtles pose a health risk. 25% of Cape May and 46% of Meadowlands terrapin muscle samples surpassed the U.S. Environmental Protection Agency mercury threshold for fish consumption. For snapping turtles, Lake Wapalanne had the highest percent of turtle samples surpassing the threshold (36%), followed by Kearny Freshwater Marsh (33%) and Lake Hopatcong (28%). Based on the results of this study it is crucial to implement human consumption advisories for consumed turtle species. Neither the commercial or recreational harvest of snapping turtles in New Jersey is well understood. We therefore administered a survey to learn about current harvest practices, willingness of commercial and recreational harvesters to pay increased license fees, and their willingness to comply with new regulations. Respondents to the recreational harvest survey collected approximately 2,285 snapping turtles between 2012 and 2014. Respondents from the commercial harvesting survey reported collecting 1,506 turtles during the 2014 season. Commercial harvesters are willing to pay a higher permit price, up to $29.22, to keep their harvesting privileges. The results of this study suggest diamondback terrapin and snapping turtles pose a human consumption health risk due to elevated mercury concentrations. We suggest consumption advisories be developed for snapping turtles starting with locations of heavy harvest while advising the sensitive population to avoid the consumption of turtles. Based on the results of the harvest surveys we can suggest both recreational and commercial harvesters are willing to follow regulations in order to ensure future harvest. Harvesters are also willing to pay a higher permit price to keep their current harvesting privileges