<p> The objectives of this study were to measure injuries and impairments directly observed from gags <i>Mycteroperca microlepis</i> caught and released within a large-scale recreational fishery, develop methods that may be used to rapidly assess the condition of reef fish discards, and estimate the total portion of discards in the fishery that suffer latent mortality. Fishery observers were placed on for-hire charter and headboat vessels operating in the Gulf of Mexico from June 2009 through December 2012 to directly observe reef fishes as they were caught by recreational anglers fishing with hook-and-line gear. Fish that were not retained by anglers were inspected and marked with conventional tags prior to release. Fish were released in multiple regions over a large geographic area throughout the year and over multiple years. The majority of recaptured fish were reported by recreational and commercial fishers, and fishing effort fluctuated both spatially and temporally over the course of this study in response to changes in recreational harvest restrictions and the Deepwater Horizon oil spill. Therefore, it could not be assumed that encounter probabilities were equal for all individual tagged fish in the population. Fish size and capture depth when fish were initially caught-and-released also varied among individuals in the study and potentially influenced recapture reporting probabilities. The Cox proportional hazards regression model was used to control for potential covariates on both the occurrence and timing of recapture reporting events so that relative survival among fish released in various conditions could be compared. A total of 3,954 gags were observed in this study, and the majority (77.26%) were released in good condition (condition category 1), defined as fish that immediately submerged without assistance from venting and had not suffered internal injuries from embedded hooks or visible damage to the gills. However, compared to gags caught in shallower depths, a greater proportion of gags caught and released from depths deeper than 30 meters were in fair or poor condition. Relative survival was significantly reduced (alpha <u>&lt;</u>0.05) for gags released in fair and poor condition after controlling for variable mark-recapture reporting rates for different sized discards among regions and across months and years when individual fish were initially captured, tagged and released. Gags released within the recreational fishery in fair and poor condition were 66.4% (95% C.I. 46.9 to 94.0%) and 50.6% (26.2 to 97.8%) as likely to be recaptured, respectively, as gags released in good condition. Overall discard mortality was calculated for gags released in all condition categories at ten meter depth intervals. There was a significant linear increase in estimated mortality from less than 15% (range of uncertainty, 0.1-25.2%) in shallow depths up to 30 meters, to 35.6% (5.6-55.7%) at depths greater than 70 meters (p &lt; 0.001, R² = 0.917). This analysis demonstrated the utility of the proportional hazards regression model for controlling for potential covariates on both the occurrence and timing of recapture events in a large-scale mark-recapture study and for detecting significant differences in the relative survival of fish released in various conditions measured under highly variable conditions within a large-scale fishery.</p>

<p> This thesis estimates the impacts of rooftop photovoltaic (PV) capacity on electricity generation and CO2 emissions in America's Pacific Northwest. The region's demand for electricity is increasing at the same time that it is attempting to reduce its greenhouse gas emissions. The electricity generated by rooftop PV capacity is expected to displace electricity from fossil fueled electricity generators and reduce CO2 emissions, but when and how much? And how can this region maximize and focus the impacts of additional rooftop PV capacity on CO2 emissions? To answer these questions, an hourly urban rooftop PV generation profile for 2009 was created from estimates of regional rooftop PV capacity and solar resource data. That profile was compared with the region's hourly fossil fuel generation profile for 2009 to determine how much urban rooftop PV generation reduced annual fossil fuel electricity generation and CO2 emissions. Those reductions were then projected for a range of additional multiples of rooftop PV capacity. The conclusions indicate that additional rooftop PV capacity in the region primarily displaces electricity from natural gas generators, and shows that the timing of rooftop PV generation corresponds with the use of fossil fuel generators. Each additional Wp/ capita of rooftop PV capacity reduces CO2 emissions by 9,600 to 7,300 tons/ year. The final discussion proposes some methods to maximize and focus rooftop PV impacts on CO2 emissions, and also suggests some questions for further research.</p>

Heterogeneous Wireless Networks (HWNs) are composite networks made of different wireless access technologies, possibly with overlapping coverage. Users with multi-mode terminals in HWNs will be able to initiate connectivity in the access technology that best suits their attributes and the requirements of their applications. The true potential of HWNs, however, is only realized through allowing users to maintain their sessions when toggling from one access technology to another. Such inter-technology handoffs, called vertical handoffs, will enable users to persistently select the most appropriate network, and not just at session initiation. For operators, HWNs pave the road to higher profitability through more capable networks where the complementary advantages of individual access technologies are combined. However, the characteristics of HWNs challenge traditional arguments for designing Radio Resource Management (RRM) frameworks. Managing the resources of an access technology in an HWN independently of other networks with which its overlaid risks underutilization and resource mismanagement. The dynamic nature of user demands in HWNs also calls for RRM modules with controlled operational cost. More importantly, the unique characteristics of HWNs call for non-traditional solutions that exploit the ``complementarity" of the individual networks. In this thesis, we address these issues through proposing a framework for RRM in HWNs. Our framework comprises three key components. The first component is aimed at improving allocation policies in HWNs through joint allocation policies involving provisioning and admission control. In addition, we outline the basis for achieving robust provisioning that accommodates variability in user demands, but also in network capabilities. The second component is concerned with controlling the operational cost of RRM modules. As a case study, we choose bandwidth adaptation algorithms and optimize their performance. We also introduce the notion of stochastic triggers which enables operators to direct the operation of a RRM module based on the operator's objectives and network conditions. In the third component, we introduce a new module that exploits vertical handoffs to the benefit of network operators. Such operator motivated vertical handoffs can be utilized in instances of congestion control. They can also be used proactively to achieve long-term objectives such as load balancing or service delivery cost reduction. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2007-09-28 04:54:46.819

No description available.

<p> Semi-arid forests are in a period of rapid transition as a result of unprecedented landscape scale fires, insect outbreaks, drought, and anthropogenic land use practices. Understanding how historically episodic disturbances led to coherent forest structural and spatial patterns that promoted resilience and resistance is a critical part of addressing change. Here my coauthors and I apply metabolic scaling theory (MST) to examine scaling behavior and structural patterns of semi-arid conifer forests in Arizona and New Mexico. We conceptualize a linkage to mechanistic drivers of forest assembly that incorporates the effects of low-intensity disturbance, and physiologic and resource limitations as an extension of MST. We use both aerial LiDAR data and field observations to quantify changes in forest structure from the sub-meter to landscape scales. We found: (1) semi-arid forest structure exhibits MST-predicted behaviors regardless of disturbance and that MST can help to quantitatively measure the level of disturbance intensity in a forest, (2) the application of a power law to a forest overstory frequency distribution can help predict understory presence/absence, (3) local indicators of spatial association can help to define first order effects (e.g. topographic changes) and map where recent disturbances (e.g. logging and fire) have altered forest structure. Lastly, we produced a comprehensive set of above-ground biomass and carbon models for five distinct forest types and ten common species of the southwestern US that are meant for use in aerial LiDAR forest inventory projects. This dissertation presents both a conceptual framework and applications for investigating local scales (stands of trees) up to entire ecosystems for diagnosis of current carbon balances, levels of departure from historical norms, and ecological stability. These tools and models will become more important as we prepare our ecosystems for a future characterized by increased climatic variability with an associated increase in frequency and severity of ecological disturbances. </p>

The aim of the study was to investigate flexitime as a potential moderator to reduce the administrative employee stress, and to reduce the negative aspects associated with stress through the use of flexitime programmes. This exploratory study was conducted in a tertiary environment. The literature review explores the core areas of the main and sub-variables. A literature review was conducted relating to the key variables of the study, that is, flexitime and stress. In terms of flexitime, emphasis was placed on the benefits of flexitime, flexible work practice and the drawbacks of flexitime. In terms of stress, emphasis was placed on stress reduction, work/life balance and employee commitment. This study was conducted with a sample of 97 subjects from a tertiary environment. The data was collected using questionnaires, and reliability was also determined. Various statistical techniques were used to test the hypotheses. Data was analysed using both descriptive and inferential statistics and the results were presented using tabular and graphical representations. Furthermore, comparisons were made with studies of other researchers who have embarked on this area of the study or studies close to this research topic. The study shows correlations and significant associations with employee stress and flexitime. The findings also indicate that stress can be reduced through the moderator, that is, flexitime. / Thesis (M.Com.)-University of KwaZulu-Natal, Westville, 2011.

<p> Despite an increasing interest among land managers in collaborative management and learning from place-based Indigenous knowledge systems, natural resource management negotiations between Indigenous communities and government agencies are still characterized by distrust, conflict, and a history of excluding Indigenous peoples from decision-making. In addition, many scholars are skeptical of Indigenous communities attempting to achieve self-determination through bureaucratic and scientific systems, which can be seen as potential mechanisms for co-opting Indigenous community values (e.g. Nadasdy 2003). </p><p> This dissertation considers how Indigenous communities and state agencies are meeting contemporary natural resource governance challenges within the Pacific Northwest. Taking a community-engaged scholarship approach, the work addresses two exemplar case studies of Indigenous resource management negotiations involving forest management with the Karuk Tribe in California (U.S.) and the X&aacute;xli'p Indigenous community in British Columbia (Canada). These cases explore the ways and degree to which Indigenous peoples are advancing their self-determination interests, as well as environmental and cultural restoration goals, through resource management negotiations with state agencies&mdash;despite the ongoing barriers of uneven power relations and territorial disputes. </p><p> Through the 1990s and 2000s, both the X&aacute;xli'p and Karuk communities engaged with specific government policies to shift status quo natural resource management practices affecting them. Their respective strategies included leveraging community-driven management plans to pursue eco-cultural restoration on their traditional territories, which both overlap with federal forestlands. In the X&aacute;xli'p case, community members successfully negotiated the creation of the X&aacute;xli'p Community Forest, which has provided the X&aacute;xli'p community with the exclusive right to forest management within the majority of its traditional territory. This <i>de jure</i> change in forest tenure facilitated a significant transfer of land management authority to the community, and long-term forest restoration outcomes. In the Karuk case, tribal land managers leveraged the Ti Bar Demonstration Project, a <i>de facto</i> co-management initiative between the Forest Service and the Karuk Tribe, to conduct several Karuk eco-cultural restoration projects within federal forestlands. Because the Ti Bar Demonstration Project was ultimately abandoned, the main project outcome was building the legitimacy of Karuk land management institutions and creating a wide range of alliances that support Karuk land management approaches. </p><p> Through my case studies, I examined how Indigenous resource management negotiations affect knowledge sharing, distribution of decision-making authority, and longstanding political struggles over land and resource access. I first asked, how is Indigenous knowledge shaping natural resource management policy and practice? My analysis shows that both communities are strategically linking disparate sets of ideas, including Traditional Ecological Knowledge (TEK) and Western scientific knowledge, in order to shape specific natural resource governance outcomes. My second question was, how does access to land and resources shift through Indigenous resource management agreements? This work demonstrates that both communities are shifting access to land and resources by identifying "pivot points": existing government policies that provide a starting point for Indigenous communities to negotiate self-determination through both resisting and engaging with government standards. And third, I considered how do co-management approaches affect Indigenous sovereignty and self-determination? The different case outcomes indicate that the ability to uphold Indigenous resource management agreements is contingent upon establishing long-term institutional commitments by government agencies, and the broader political context. </p><p> This work emphasizes the importance of viewing the world from the standpoint of individuals who are typically excluded from decision-making (Harding 1995, 1998). Pursuing natural resource management with Indigenous peoples is one way for state agencies to gain innovative perspectives that often extend beyond standard resource management approaches, and consider longstanding relationships between people and the environment in a place-based context. Yet the assumption that tribal managers would export Indigenous knowledge to agency "professionals" or other external groups, supposedly acting on behalf of Indigenous peoples, reflects a problematic lack of awareness about Indigenous perspectives on sovereignty and self-determination--central goals for Indigenous communities that choose to engage in natural resource management negotiations. </p><p> Several implications emerge from these findings. First, Indigenous community representatives need to be involved in every step of natural resource management processes affecting Indigenous territories and federal forestlands, especially given the complex, multi-jurisdictional arrangements that govern these areas. Second, there is a strong need to generate funding that enables Indigenous communities to self-determine their own goals and negotiate over land management issues on a more level playing field. Finally, more funding must be invested in government programs that support Indigenous resource management.</p>

<p> Ordered mesoporous carbon (OMC) materials have attracted great interests from NASA due to their remarkable properties, such as high specific surface area, regular and tunable pore size. These features show great potential for being used in the water recovery system (WRS) in the International Space Station (ISS) as potential adsorbents. Various methods have been explored on the OMC preparation and modification to achieve better adsorption results. In this research, acrylic acid was used as a carbon precursor to synthesize OMC using a common silica mesoporous template (SBA-15). The influence of silica template amount was tested by using different ratios of SBA-15 to acrylic acid. The modification processes were conducted by immersing methods using four different aqueous solutions: 30% ammonium hydroxide, 0.1% sodium hydroxide, 1 mol/L aluminum chloride, and 0.02 g/mL urea solution. BET-SSA, FT-IR, TEM, TGA, and XRD were used to characterize the structures of OMCs and modified OMCs. It demonstrated that all the products had well-ordered hexagonal structure. The modifying procedures had eroded the surface of the OMC, but the highly ordered structures had been preserved based on the TEM and XRD results. FT-IR analysis indicated that the functional groups were introduced to the surface of the modified OMCs, which affected the adsorption capacity significantly. Resorcinol, a typical total organic carbon (TOC) model compound, was selected to evaluate the adsorption behavior of the OMCs and modified OMCs. Adsorption study illustrates that OMC produced by 3:1 ratio of SBA-15 to acrylic acid showed a higher adsorption capacity than that of OMCs produced with other ratios. The ammonium hydroxide modified OMC had the highest adsorption capacity of 40.6 mg/g for resorcinol removal, compared with that of the other three modified OMCs.</p>

<p> Pinyon-juniper (<i>Pinus monophylla &ndash; Juniperus osteosperma</i>) woodlands have expanded and infilled over the last 150 years to cover more than 40 million ha in the Great Basin. Many land managers seek to remove Pinyon-juniper trees using a variety of treatments. This thesis looks at six different Pinyon-juniper removal projects in Central and Eastern Nevada. We established a total of 73 vegetation and soil monitoring plots (38 treated, 35 adjacent untreated) across six Pinyon-juniper removal projects in Central and Eastern Nevada to look at the effects of fire, hand thinning, and chaining. The four burns examined together in Chapter 1 had similar elevation, precipitation, and pre-treatment vegetation communities in the untreated areas, but the treated areas had significantly different responses to treatment. With nonmetric multidimensional scaling (NMS), we found a useful 3-axis ordination of the plots (stress=7.1, R²=.966). Within ordination space, the treated plots were well grouped by parent material. These results informed a Poisson generalized linear model that found parent material factorized explained 86.5% of the deviance in cheatgrass (<i>Bromus tectorum</i>) cover at the treated plots. The projects on soils derived from welded tuff had very little cheatgrass while soils derived from limestone or mixed limestone/volcanics were dominated by cheatgrass. Parent material should be considered an important factor when planning Pinyon-juniper removal treatments. Chapter 2 examined the effects of a hand thinning. The hand thinning significantly reduced tree cover [F(1,10) = 7.43, p = 0.027] to less than 2%. Perennial grasses on the site are slightly higher in the treated area. There was a significant increase in perennial grass cover from 2013 to 2014 [F(1,10) = 14.5, p = 0.003]. The hand thinning did not have significant effects on shrubs, annual grasses, annual forbs, perennial forbs, ground cover, stability, species richness, diversity, infiltration, or gap structure. Because hand thinning does not remove the shrubs or other perennials, site resistance can be maintained. With sufficient understory vegetation to maintain resistance post treatment (as in phase I or early phase II Pinyon-juniper woodlands), nonnative annual grasses are less likely to dominate after treatment. Chapter 3 examined the effects of a chaining. The effects of the 40-year old chaining are still significant even though Pinyon-juniper trees are reinvading and make up >5% of the cover in the treated area. The treated areas still have a much more productive understory than adjacent untreated areas. Perennial grass cover, frequency, and density was 2-5 times greater in the chained area. The treated area had fewer large gaps (>100 cm). However, interspace infiltration times were slower in the treatment (t(4)=-2.14, p=0.09). Surface and subsurface soil aggregate stability remained significantly lower in the treatment for vegetation-protected and unprotected samples (t(4)=3.53, p=0.024; t(4)=3.10, p=0.036). Chainings have long-term benefits for vegetation, but also long term impacts on soils and hydrologic ecosystem processes. When planning Pinyon-juniper removal treatments, land managers should consider the plant community, temperature and precipitation regime, and soils at the potential treatment location to better achieve desired outcomes.</p>

<p> Forecasts of hydrological information are vital for many of society's functions. Availability of water is a requirement for any civilization, and this necessitates quantitative estimates of water for effective resource management. The research in this dissertation will focus on the forecasting of hydrological quantities, with emphasis on times of anomalously low water availability, commonly referred to as droughts. Of particular focus is the quantification of uncertainty in hydrological forecasts, and the factors that affect that uncertainty. With this focus, Bayesian methods, including ensemble data assimilation and multi-model combinations, are utilized to develop a probabilistic forecasting system. This system is applied to the upper Colorado River Basin for water supply and drought forecast analysis. </p><p> This dissertation examines further advancements related to the identification of drought intensity. Due to the reliance of drought forecasting on measures of the magnitude of a drought event, it is imperative that these measures be highly accurate. In order to quantify drought intensity, hydrologists typically use statistical indices, which place observed hydrological deficiencies within the context of historical climate. Although such indices are a convenient framework for understanding the intensity of a drought event, they have obstacles related to non-stationary climate, and non-uniformly distributed input variables. This dissertation discusses these shortcomings, demonstrates some errors that conventional indices may lead to, and then proposes a movement towards physically-based indices to overcome these issues. </p><p> A final advancement in this dissertation is an examination of the sensitivity of hydrological forecasts to initial conditions. Although this has been performed in many recent studies, the experiment here takes a more detailed approach. Rather than determining the lead time at which meteorological forcing becomes dominant with respect to initial conditions, this study quantifies the lead time at which the forecast becomes entirely insensitive to initial conditions, and estimating the rate at which the forecast loses sensitivity to initial conditions. A primary goal with this study is to examine the recovery of drought, which is related to the loss of sensitivity to below average initial moisture conditions over time. Through this analysis, it is found that forecasts are sensitive to initial conditions at greater lead times than previously thought, which has repercussions for development of forecast systems.</p>