Many deglaciated watersheds possess complex longitudinal profiles and spatially variable sediment sources derived from the last glaciation. Accordingly, downstream patterns in fluvial forms and characteristics of the channel and floodplain may diverge from conventional ‘graded’ watershed models where channel slope decreases downstream. Within a small, deglaciated watershed, five distinct fluvial forms were identified and it was found that the watershed is organized in a spatially variable, but generally inverted arrangement with stable, low-energy forms dominating the upper watershed and more dynamic, high-energy forms in the lower watershed. As a consequence of this inverted and variable downstream succession, and the spatially erratic organization of glacial sediment sources, downstream trends in channel and floodplain characteristics are poorly defined, and in many cases, deviate from expected trends. This is most true for sedimentological variables where multiple co-dominant controls exist, while morphological and hydrological variables better conform to expected downstream trends.

There are several potential applications for a high data density barcode that can be easily photographed and decoded by mobile phones, but no such symbology currently exists. As a result, a new barcode was designed to exploit the low-pass characteristic of a camera phone channel and is presented as a means of facilitating wireless optical communication with mobile phones. A channel model was established and subsequent simulation results led to the design of a colour barcode with encoding done in the Discrete Cosine Transform domain. A waterfilling process and a noise-shaping algorithm enhance performance, while a new fast acquisition method allows for rotational and size invariance. An outer Accumulate-Repeat-Accumulate code is employed, followed by an inner Reed Muller code with a rate varying according to spatial frequency. The final barcode data-density is 3.5 times greater than the leading symbology and has proven robust to various impediments imposed by camera phones.

In wireless channels and many other channels, interference is a central phenomenon. Mitigating interference is a key to improving system performance. To find the limit of the achievable rates for these channels in the presence of interference, the two-user Gaussian interference channel has been the subject of intensive study in network information theory. However, most current results have been obtained by assuming Gaussian input distributions. While optimal in single-user Gaussian channels, the issue with this assumption is that the Gaussian noise becomes the worst noise when the input distribution is also Gaussian. In this thesis, we propose a class of discrete constellations. We show that this class of constellations can automatically achieve the same sum rates as schemes that treat interference as noise or perform time sharing.

Many deglaciated watersheds possess complex longitudinal profiles and spatially variable sediment sources derived from the last glaciation. Accordingly, downstream patterns in fluvial forms and characteristics of the channel and floodplain may diverge from conventional ‘graded’ watershed models where channel slope decreases downstream. Within a small, deglaciated watershed, five distinct fluvial forms were identified and it was found that the watershed is organized in a spatially variable, but generally inverted arrangement with stable, low-energy forms dominating the upper watershed and more dynamic, high-energy forms in the lower watershed. As a consequence of this inverted and variable downstream succession, and the spatially erratic organization of glacial sediment sources, downstream trends in channel and floodplain characteristics are poorly defined, and in many cases, deviate from expected trends. This is most true for sedimentological variables where multiple co-dominant controls exist, while morphological and hydrological variables better conform to expected downstream trends.

Tottering and leaner mutant mice carry mutations in the pore-forming subunit (1A) of P/Q-type (CaV 2.1) voltage-gated calcium ion (Ca2+) channels that result in reduced Ca2+ current density. Since Ca2+ influx via voltage-dependent Ca2+ channels regulates important Ca2+-dependent neuronal processes including neurotransmitter release and synaptogenesis, we assessed effects of these mutations on hippocampus volume, neuronal density, neuronal morphology of hippocampal pyramidal cells in adult (six-month-old) mice, and adult neurogenesis in three-week-old and six-month-old mice. Hippocampal volume and neuronal density were assessed using hematoxylin and eosin stained serial sections. Neuronal morphology was assessed using Golgi-Cox staining as well as ultrastructural assessment using transmission electron microscopy. Adult hippocampal neurogenesis was assessed using standard 5-bromo-2’-deoxyuridine (BrdU) labeling with fluorescent immunohistochemistry (IHC) and proliferating cell nuclear antigen (PCNA) with diaminobenzidine IHC. To determine neuron and astrocyte survival, we used fluorescent double labeling for neurons with BrdU-neuronal nuclei IHC or astrocytes using BrdU-glial fibrillary acidic protein, respectively. Fluoro-Jade histochemistry was used to assess numbers of degenerating cells in the dentate gyrus subgranular zone. Decreased hippocampus volume was observed in tottering female mice and increased dentate hilar and CA1 cell density in mutant mice compared to wild type mice. Cell proliferation was increased in the hilus and combined CA3, CA2 and CA1 regions of mutant mice compared to wild type mice. Decreased total dendritic length and decreased number of dendritic intersections was observed in tottering mice compared to wild type mice. The decrease in dendritic arborization of tottering mice occurred at the concentric circles close to the neuronal cell body indicating that basal dendrites of CA1 pyramidal neurons are reduced. Taken together, P/Q-type voltage gated calcium channel mutation has age variable influence on adult hippocampal cell proliferation, and it altered neuronal morphology in terms of dendritic complexity in tottering mice, while the leaner mutation reduced mitochondrial density.

The relay channel plays an integral role in network communication systems. An intermediate node acts as a relay to facilitate the communication between the source and the destination. If the rate of codewords is less than the capacity of the source-relay link, the relay can decode the source's messages and forward them to the destination. On the contrary, if the rate of codewords is greater than the capacity of the source-relay link, the relay cannot decode the messages. Nevertheless, the relay can still compress its observations and then send them to the destination. Obviously, if the relay-destination link is of a capacity high enough such that the relay's observations can be losslessly sent to the destination, then the maximum message rate can be achieved as if the relay and the destination can jointly decode. However, when the relay-destination link is of a limited capacity such that the relay's observation cannot be losslessly forwarded to the destination, then what is the maximum achievable rate from the source to the destination? This problem was formulated by Cover in another perspective [7], i.e., what is the minimum rate of the relay-destination link such that the maximum message rate can be achieved? We try to answer this Cover's problem in this thesis. First, a sufficient rate to achieve the maximum message rate can be obtained by Slepian-Wolf coding, which gives us an upper bound on the optimal relay-destination link rate. In this thesis, we show that under some channel conditions, this sufficient condition is also necessary, which implies that Slepian-Wolf coding is already optimal. Hence, the upper bound meets exactly the minimum value of the required rate. In our approach, we start with the standard converse proof. First, we present a necessary condition for achieving the maximum message rate in the single-letter form. Following the condition, we derive a theorem, which is named as "single-letter criterion". The "single-letter criterion" can be easily utilized to verify different channels. Then we show that for two special cases: when the source-relay link and the source-destination link of the relay channel are both binary symmetric channels (BSCs), and when they are both binary erasure channels (BECs), Slepian-Wolf coding is optimal in achieving the maximum message rate. Moreover, the maximum message rates of these two special channels are also calculated in this thesis.

Headwater streams provide diverse habitat for aquatic organisms, drinking water for downstream communities and abundant recreational activities. The addition of in-stream wood to headwater channels can influence the hydrology, morphology and ecology of the system. The recruitment of wood to the channel and the export mechanisms determine the wood load and structure types formed in-stream, thus altering the channel’s morphological response. This research examined the effects of in stream wood on channel morphology in two headwater streams along the eastern slopes of the Canadian Rocky Mountains; Lyons East (LE) and Corolla Creek (CC). Lyons East has natural and anthropogenic disturbance (burned and salvage-logged) in the watershed, while Corolla Creek has anthropogenic (grazing and recreation) disturbances in the watershed. An assessment of the longitudinal spatial distribution and a reach-scale geomorphic classification were conducted to investigate the impacts of in-stream wood on channel morphology, pool formation and sediment storage. The spatial distribution of in-stream wood was 1.49 sites/100m for both watersheds, results that are comparable to previously conducted studies in similar geographic watersheds. The types of structures found in both watersheds were predominately jam formations (LE - 43%, CC - 47%), which is consistent with the wood loading and spatial distribution conceptual model previously developed by Whol and Jaeger (2009) for in-stream wood accumulations in mountain streams. At the reach-scale level of analysis, in-stream wood was found to impact channel morphology and pool forming processes. The addition of wood to the stream caused half of the studied reaches to have forced pool-riffle morphology. For all six selected study reaches, there was a decrease in expected pool spacing and an increase in the diversity of pool types. The relationship between wood-affected pools and sediment storage was examined and the results show that more sediment was stored in the burned/salvage logged reaches. Cohesive sediment was stored only in pools influenced by wood structures for half of the studied reaches. V* was generally higher in wood-affected pools for five of the six study reaches. The weighted average (V*w), which provides information regarding the storage of cohesive at the reach scale, was greater in Lyons East than in Corolla Creek. The presence of both exposed bedrock in the channel as well as the amount of vegetation are possible reasons for the smaller amounts of sediment observed in Corolla Creek. The observations from this reach scale investigation led to the development of a conceptual model, which can be used to predict the location of cohesive sediment storage in headwater streams of the Oldman River Basin. This model highlights the relationship between simultaneous recruitment of in-stream wood and sediment from local sources as a mechanism for protecting and storing cohesive sediment deposits. This research examined channel responses to in-stream wood within the context of land-use planning and Alberta’s Water for Life Strategy. There was evidence of lateral channel migration in the floodplain of both watersheds. At some sites, the channel shifted up to 30 metres while in other sections of the watershed, the channel was confined within a narrow valley. Accordingly, it is recommended that the current salvage logging guidelines be changed to include a flexible riparian buffer that would more appropriately reflect the diversity in riparian widths throughout the watersheds. In addition the best management practice is to allow natural in-stream wood processes to evolve and not to remove in-stream wood from the channel. The in-stream wood provides diverse aquatic habitat and the cycle of wood being recruited and being in the stream is part of the natural ecosystem in forested environments.

A network of n transmitters and n receivers is considered. We assume that transmitter i aims to send data to its designated destination, receiver i. Communications occur in a single-hop fashion and destination nodes are simple linear receivers without multi-user detection. Therefore, in each time slot every source node can only talk to one other destination node. Thus, there is a total of n communication links. An important question now arises. How many links can be active in such a network so that each of them supports a minimum rate Rmin? This dissertation is devoted to this problem and tries to solve it in two di erent settings, dense and extended networks. In both settings our approach is asymptotic, meaning, we only examine the behaviour of the network when the number of nodes tends to in nity. We are also interested in the events that occur asymptotically almost surely (a.a.s.), i.e., events that have probabilities approaching one as the size of the networks gets large. In the rst part of the thesis, we consider a dense network where fading is the dominant factor a ecting the quality of transmissions. Rayliegh channels are used to model the impact of fading. It is shown that a.a.s. log(n)^2 links can simultaneously maintain Rmin and thus be active. In the second part, an extended network is considered where nodes are distant from each other and thus, a more complete model must take internode distances into account. We will show that in this case, almost all of the links can be active while maintaining the minimum rate.

Characterizing probability distribution function for the input of a communication channel that achieves the maximum possible data rate is one of the most fundamental problems in the field of information theory. In his ground-breaking paper, Shannon showed that the capacity of a point-to-point additive white Gaussian noise channel under an average power constraint at the input, is achieved by Gaussian distribution. Although imposing a limitation on the peak of the channel input is also very important in modelling the communication system more accurately, it has gained much less attention in the past few decades. A rather unexpected result of Smith indicated that the capacity achieving distribution for an AWGN channel under peak constraint at the input is unique and discrete, possessing a finite number of mass points. In this thesis, we study multiple access channel under peak constraints at the inputs of the channel. By extending Smith's argument to our multi-terminal problem we show that any point on the boundary of the capacity region of the channel is only achieved by discrete distributions with a finite number of mass points. Although we do not claim uniqueness of the capacity-achieving distributions, however, we show that only discrete distributions with a finite number of mass points can achieve points on the boundary of the capacity region. First we deal with the problem of maximizing the sum-rate of a two user Gaussian MAC with peak constraints. It is shown that generating the code-books of both users according to discrete distributions with a finite number of mass points achieves the largest sum-rate in the network. After that we generalize our proof to maximize the weighted sum-rate of the channel and show that the same properties hold for the optimum input distributions. This completes the proof that the capacity region of a two-user Gaussian MAC is achieved by discrete input distributions with a finite number of mass points.

Achieving a higher transmission rate had always been a goal in the field of communications. Having a two-way channel in which two nodes transmit and receive data at the same time, is an important tool to achieve this goal. A two-way channel is the first step from point-to-point communication channel toward multi-user networks. In its ideal form, we can transmit data two times faster by using a perfect two-way channel. However, the area of two-way channels had not been of interest of researchers during the past years and number of articles on this area is considerably low comparing to other types of multi-user communication networks, such as multiple-access channel, broadcast channel and interference channel. On the other hand, use of analog-to-digital converters (ADC) is a must in modern systems to enable us to analyze data faster; nevertheless, presence of ADC add some other difficulties to the system. In this thesis, different scenarios about two-way channel are studied. The Shannon's model of two-way channel and his inner and outer bounds on the capacity of this channel are presented. For the Gaussian Two-Way Channel with quantized output, in which the ambient noise has a Gaussian distribution, the expression of Shannon's inner bound for both Gaussian and discrete inputs are derived. The best uniform quantizer to obtain the maximum achievable rate for Gaussian input is found numerically. Then we will evaluate the additive noise model for the quantizer from an information theoretic point of view. For the discrete input, the method of rotating one input with respect to other one is employed to enlarge the achievable rate region. At last, two scenarios will be studied in which, minimizing the power of interference, does not necessarily maximizes the transmission rate.