Previous studies of serum adenosine deaminase have neglected consideration of the two molecular forms of this enzyme that exist in human tissues. The purpose of this study was to survey the distribution of these forms in normal and pathological human sera. Both molecular forms were present in normal serum, though the small form predominated. This form also predominates in lymphocytes, erythrocytes, and in tissues with high specific activity of this enzyme. The ratio of the two forms is different for plasma and serum and can change with sample storage. The activity of the small form varied over a wider range than the activity of the large form in normal serum. Many pathological samples showed an altered distribution of the two forms. This study demonstrates the potential usefulness of serum forms of adenosine deaminase for distinguishing some pathological conditions.

This study examined the impact of active layer detachments (ALDs) on seasonal dissolved nitrogen (N) export from continuous permafrost headwater catchments at the Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, Nunavut. Runoff samples collected throughout the summer of 2012 from an undisturbed catchment (Goose; GS) and from one that was disturbed by ALDs (Ptarmigan; PT) were analyzed for dissolved inorganic ions and species of total dissolved N (TDN), including dissolved organic N (DON) and dissolved inorganic N (DIN; ammonium (NH4+), nitrite (NO2-), and nitrate (NO3-)). Rainfall samples were also collected for dissolved ions analyses. Select runoff and rainfall samples were analyzed for stable isotopes of nitrogen and oxygen in NO3- (δ15N-NO3- and δ18O-NO3-, respectively) to determine its origin streamwater. Data from 2012 were compared to predisturbance data to assess the long-term effects of ALDs on N export. ALDs increased the proportion of DIN/TDN in PT from 4% (predisturbance) to 37% in 2012. The increase in DIN/TDN in PT largely resulted from significantly higher NO3- in runoff. Values of δ18O and δ15N-NO3- as well as correlations between NO3- and major ions indicated that the higher NO3- in PT was due to the exposure of mineral soils in ALDs, which likely reduced NO3- sinks (e.g. plant uptake) and increased inputs of nitrified-NO3-. Values of δ18O-NO3- during initial runoff showed that NO3- supplied from the snowpack overwhelmed NO3- sinks in PT, leading to a twelve-fold higher peak NO3- concentration relative to GS. Low δ18O-NO3- values in runoff during stormflow indicated that inputs of DIN from rainfall (1545 ± 148 and 1838 ± 174 g N-DIN to GS and PT, respectively) supplied less than 30% of the NO3- in both streams, and that exceptionally high NO3- concentrations in PT resulted from flushing of mineralized-NO3- from the mineral soils. Seasonal DIN flux was 95% higher in PT relative to GS, because NO3- export from PT was 27 times that of GS. This is the first study to show that ALDs can have persistent impacts on DIN export from High Arctic watersheds, and that this results from enhanced export of mineralized-NO3-. / Thesis (Master, Geography) -- Queen's University, 2014-05-27 10:30:38.874

We present a Markov chain analysis for studying the performance of wireless ad hoc networks. The models presented in this dissertation support an arbitrary backoff strategy. We found that the most important parameter affecting the performance of binary exponential backoff is the initial backoff window size. Our experimental results show that the probability of collision can be reduced when the initial backoff window size equals the number of terminals. Thus, the throughput of the system increases and, at the same time, the delay to transmit the frame is reduced. In our second contribution, we present a new analytical model of a Medium Access Control (MAC) layer for wireless ad hoc networks that takes into account frame retry limits for a four-way handshaking mechanism. This model offers flexibility to address some design issues such as the effects of traffic parameters as well as possible improvements for wireless ad hoc networks. It effectively captures important network performance characteristics such as throughput, channel utilization, delay, and average energy. Under this analytical framework, we evaluate the effect of the Request-to-Send (RTS) state on unsuccessful transmission probability and its effect on performance particularly when the hidden terminal problem is dominant, the traffic is heavy, or the data frame length is very large. By using our proposed model, we show that the probability of collision can be reduced when using a Request-to-Send/Clear- to-Send (RTS/CTS) mechanism. Thus, the throughput increases and, at the same time, the delay and the average energy to transmit the frame decrease. In our third contribution, we present a new analytical model of a MAC layer for wireless ad hoc networks that takes into account channel bit errors and frame retry limits for a two-way handshaking mechanism. This model offers flexibility to address design issues such as the effects of traffic parameters and possible improvements for wireless ad hoc networks. We illustrate that an important parameter affecting the performance of binary exponential backoff is the initial backoff window size. We show that for a low bit error rate (BER) the throughput increases and, at the same time, the delay and the average energy to transmit the frame decrease. Results show also that the negative acknowledgment-based (NAK-based) model proves more useful for a high BER. In our fourth contribution, we present a new analytical model of a MAC layer for wireless ad hoc networks that takes into account Quality of Service (QoS) of the MAC layer for a two-way handshaking mechanism. The model includes a high priority traffic class (class 1) and a low priority traffic class (class 2). Extension of the model to more QoS levels is easily accomplished. We illustrate an important parameter affecting the performance of an Arbitration InterFrame Space (AIFS) and small backoff window size limits. They cause the frame to start contending the channel earlier and to complete the backoff sooner. As a result, the probability of sending the frame increases. Under this analytical framework, we evaluate the effect of QoS on successful transmission probability and its effect on performance, particularly when high priority traffic is dominant. / Graduate

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The chemistry of stratospheric ozone is discussed and particular consideration is given to the role of chlorine compounds and to the impact of human activity on the ozone layer. An account is given of the methods used by other researchers to measure hydrogen chloride (HC1) in the stratosphere and their results are summarized. The pressure modulator radiometer (PMR) is an instrument which can be used to make remote measurements of atmospheric temperature and composition by sensing the radiation transmitted by or emitted from an atmospheric path containing gases with absorption bands in the infra-red. A balloon-borne PMR has been used to detect the absorption of solar radiation by the fundamental vibration-rotation band of HC1 at 3.5 micrometres. Using a limb scanning technique, the mixing ratio profile of HC1 has been measured over the height range, 16 to 39 km. It is shown that the amount of HC1 in an atmospheric path can be related to the PMR signals using a line-by-line method. The theory is developed in sufficiently general terms for it to be applicable to line-by-line calculations for many other gases with absorption bands in the infra-red. Consideration is given to the modelling of PMR measurements of transmission and emission both in the atmosphere and in the laboratory. The instrument used to measure HC1 is described in detail. The problems associated with the interpretation of the signals are discussed and an account of the instrument's laboratory testing is given. The reduction of the balloon flight data is described and the method used to retrieve the mixing ratio profile from the PMR signals is presented.

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Conditional sampling techniques were used to analyze airbourne carbon dioxide and water vapour flux traces recorded during the FIFE experiment. Two analysis methods based on quadrant analysis were used to isolate and examine extreme contributions to estimates of the mean flux. The first method was a graphical analysis based on 'hyperbolic holes'. This method was used to attain the result that 80% of the flux-fraction is carried by 20% of the time-fraction. The second method, based on quadrant analysis, permitted the distinction of physical structures which are thought to represent the signatures of turbulent flux structures such as eddies or thermals. Overall results indicate that mean flux estimates over the FIFE site are dominated by a very few intermittent extreme events.

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