Showing papers by "Ryerson University published in 2023"

Documenting the impacts of increasing salinity in freshwater and coastal ecosystems: Introduction to the special issue

Abstract: Freshwater salinization is the process of changing ion concentrations (e.g., Na+, Mg2+, K+, Cl−, CO 3 2 − , SO 4 2 − ) relative to background levels due to human activities (e.g., agriculture, application of road de-icing salts, water and resource extraction, climate change, and sea-level rise; Williams 2001; Cañedo-Argüelles et al. 2016). Although considerably less studied than other environmental issues (Cañedo-Argüelles 2020), salinization is widely accepted as presenting major challenges to freshwater and coastal biodiversity (Cunillera-Montcusí et al. 2022). Existing data and research show a clear rise in freshwater salinization worldwide (Dugan et al. 2017; Cañedo-Argüelles 2020; Jeppesen et al. 2020; Kaushal et al. 2021), yet key knowledge gaps and management challenges remain due to the complexity (Kaushal et al. 2018) and prevalence of the problem (Cañedo-Argüelles 2020; Jeppesen et al. 2020). Current literature has neglected to provide unbiased geographic coverage (Cunillera-Montcusí et al. 2022), and ecosystem-level responses (e.g., functions and services) are rarely assessed (Herbert et al. 2015). Compelling calls for research agendas that address the need for salinization research at multiple scales (e.g., global, regional, local) are well timed (Cunillera-Montcusí et al. 2022). One identified research gap points to the need for networks of researchers working together at regional scales using experimental approaches to identify impacts on biodiversity, community salinity thresholds, and landscape-scale drivers. Here, we document the results of a networked Global Salt Initiative (GSI) that performed in situ experiments on lakes to look at ecosystem-level impacts: their findings suggest that North American and European water quality guidelines for salt are far too low to prevent ecosystem-level impacts. The further purpose of this Special Issue (SI) is to document the results of ecosystem-level impacts of increasing salinity on lake and coastal area biodiversity and ecosystem functioning from a variety of perspectives. Salinity is an important environmental parameter, like temperature and light, that directly affects freshwater organisms via osmotic stress (Silver and Donini 2021). Despite the rise in freshwater salinization worldwide, however, from a socioeconomic perspective, salts are perhaps still viewed as a natural component of ecosystems with negligible impacts on biodiversity and ecosystem functioning (Gorostiza and Saurí 2019). Moreover, current management solutions are technically challenging and expensive (Cañedo-Argüelles 2020), making salinization a seemingly unavoidable consequence of many human activities. We have witnessed a substantial increase in research on freshwater salinization worldwide, including some high profile papers and reviews (Dugan et al. 2017; Kaushal et al. 2018; Hintz and Relyea 2019; Arnott et al. 2020; Dugan et al. 2020; Thorslund et al. 2021; Cunillera-Montcusí et al. 2022; Hintz et al. 2022a,b), scientific data papers (Dugan et al. 2017; Thorslund and van Vliet 2020), and three SIs devoted to the topic: (1) SI in Philosophical Transactions B (2018) on “Salt in freshwaters: causes, ecological consequences and future prospects” (Cañedo-Argüelles et al. 2019); (2) SI in Water (coming in 2022) focused on “Salinization of water resources: ongoing and future trends” (Colombani 2022); and (3) SI in Hydrobiologia (coming in 2023) focused on “Effects of induced changes in salinity on inland and coastal water ecosystems,” edited by Jeppesen, Cañedo-Argüelles, Entrekin, Padisák, and Sarma. What makes this SI in Limnology and Oceanography Letters unique is the principal focus on determining impacts of salinization on lakes and coastal ecosystems worldwide (as stated above). When faced with trying to understand the complexity of what happens when a mixture of salt ions interacts with other anthropogenically derived substances in aquatic ecosystems, experts refer to the result as a “freshwater salinization syndrome” (FSS; Kaushal et al. 2018). Like any syndrome, the combination of complex factors (chemical, biological, geological, environmental, and social) associated with freshwater salinization can result in extreme consequences like unsafe drinking water (Ehmar Khan et al. 2014; Kaushal 2016); mobilized contaminants (Herbert et al. 2015; Kaushal et al. 2022); changes in the toxicity and bioaccumulation of co-occurring pollutants such as pesticides (Saranjampour et al. 2017; Hutton et al. 2021; Xing et al. 2022); and a loss of freshwater biodiversity (James et al. 2003; Castillo et al. 2018; Hintz and Relyea 2019; Hébert et al. 2022). FSS is expected to progress in five distinct stages as outlined here (this SI) for the first time (Kaushal et al. 2022). As a result of inadequate salinity regulations (Huling and Hollocher 1972; Jackson and Jobbàgy 2005; Gorostiza and Saurí 2019; Schuler et al. 2019; Arnott et al. 2020; Hintz et al. 2022b), salinization continues to impact freshwater biodiversity and ecosystem function, as well as freshwater ecosystem services such as sector-specific water withdrawals in many regions of the world (e.g., irrigation agriculture; drinking water; van Vliet et al. 2017). The global scale and complexity of freshwater ecosystem salinization and the seemingly irreconcilable demands of various anthropogenic practices (e.g., agriculture, road-de-icing, mining) help to explain the recent increase in scientific research in this area. International teams working on freshwater salinization recently published calls for networked research approaches (e.g., coordinated mesocosm experiments across regions) that focus on the most urgent knowledge gaps (Hintz and Relyea 2019; Jeppesen et al. 2020; Cunillera-Montcusí et al. 2022). All three guest editors of this SI are a part of the networked GSI, which began with the design of a Global Salt Experiment (GSE) conceived at a GLEON (Global Lakes Ecological Observatory Network) meeting in Mohonk (New York) 2017. Interdisciplinary researchers led by Drs Shelley Arnott and William Hintz designed a large-scale, simultaneous mesocosm experiment that was performed in 16 lakes within Canada (CA), Europe (EU), and the United States (US) in the summer of 2018. The experiment was performed under natural conditions and was designed to address a lack of experimental research on the direct impacts of road de-icing salt on pristine lake zooplankton, outside of laboratory tests. The results of these regional lake mesocosm experiments are published in Hintz et al. (2022b) and in this SI as a series of six papers that either combine data to evaluate cross-regional impacts (Arnott et al. 2022) or examine unique regional effects of salt and other stressors on communities at the base of the food chain (Moffett et al. 2020; Greco et al. 2021; Astorg et al. 2022). The GSE results (i) are complemented by 14 selected research papers that examine what is known about effects of freshwater salinization on zooplankton communities worldwide; (ii) document and predict trends of ongoing increases in lake salinity in North America caused predominantly by road salt; (iii) examine complex impacts of salinity on lake associated freshwater ecosystems (e.g., urban wetlands, streams, and ponds); (iv) examine impacts of increased human land-water usage patterns causing saltwater intrusion and nutrient loadings in coastal marine areas; and (v) document the need to consider community-level impacts and the freshwater salinization syndrome. The contributions in this SI provide depth and scope in support of GSI's recent overarching paper that explains how zooplankton abundances will be lost in lakes due to current water quality guidelines (Hintz et al. 2022b). Currently, freshwater salinization is regulated through recommendations (i.e., non-legally enforced standards) that are based on laboratory toxicity tests, and the focus is on total salinity and/or chloride concentrations (e.g., chronic chloride [Cl−] guidelines for Canada and the United States are 120 and 230 mg L−1, respectively). Addressing the problem of freshwater salinization will require more rigorous guidelines that capture the complexity of ecosystems and consider the toxicity of different ion mixtures and chemical cocktails (Cañedo-Argüelles et al. 2016; Schuler et al. 2019). Recently, Hintz et al.'s (2022b) paper created heightened scientific appreciation, with over 2300 comments and 69,100 upvotes in the New Reddit Journal of Science (NRJS 2022). Such appreciation included the need for investigations into microbes that use road salt for energy; the need for knowledge about how products affect ecosystems; or the use of different substances for safe roads, such as beet juice, gravel (Finland), or sand. Without knowledge and evidence, legislative changes are unlikely. We provide a brief overview in this SI to enhance the probability of legislative change. The most important finding of our coordinated, mesocosm, experiments (on impacts of increasing salt on lake zooplankton communities) was the precipitous loss of zooplankton biomass (e.g., 50% reductions) at salt concentrations below existing chronic concentration guidelines in CA, US, and EU (Hintz et al. 2022b). Vitally, Hébert et al. (2022) showed that the loss in abundance was accompanied by a loss in zooplankton biodiversity with fewer species, reduced community diversity, and a consistent trophic shift in algal communities (dominance) across all lakes, demonstrated by increasing chlorophyll a (Chl a). Arnott et al. (2022) were unable to link sensitivity of zooplankton communities (i.e., intraspecific variation in community-level salt responses) to their original species pool or local environmental conditions. Yet, some lakes had more robust zooplankton community responses, possibly due to evolutionary adaptation (Moffett et al. 2020). Nonetheless, even the most robust zooplankton communities were lost at upper Cl− concentrations leading to a proliferation of algae released from grazing pressure. The paper by Astorg et al. (2022) uniquely investigated shifts in the algal and fungal eukaryotic plankton community using DNA metabarcoding with 18 S rRNA. They found massive compositional shifts in plankton communities with increasing salinity among diverse groups of fungal dominants and unicellular algae. Eventually, high Cl− concentrations combined with high nutrient loadings are expected to favor cyanobacteria (Porter-Goff et al. 2013), but this is not universally the case for lakes wherein cyanobacteria are absent and other groups of phytoplankton are favored in the phytoplankton community (Astorg et al. 2022). More research on effects of multiple stressors is needed. Examining interactions between Cl− and nutrients, Greco et al. (2021) exposed zooplankton communities in their mesocosms to either ambient or high nutrient levels (~ 3–4× ambient), concluding that although higher nutrients increased food availability, there was no concomitant increase in zooplankton tolerance to salt. Temperature is another key variable expected to interact with salinity, and McClymont et al. (2022) found that algae were more responsive to changes in temperature than zooplankton when subjected to interactions with Cl− as a stressor. Despite the losses in zooplankton abundance and diversity that we found in our GSI mesocosm experiments, Wersebe et al. (2021) found only slight changes in the relative abundance of Daphnia ephippia in response to increasing suburban lake salinization over 170 years (with changing [Cl−] from 1 to 150 mg L−1) in a paleolimnological study of ephippial densities in lake sediments. This ecological response in zooplankton may be explained by the possible attenuating effects of calcium and water hardness (Elphick et al. 2011). However, more research is needed to address ecological and evolutionary responses to freshwater salinization in lakes with different environmental conditions as previous studies have focused on soft water, boreal shield lakes. Dugan's research group focused on quantifying and modeling the increases in lake salinity levels across North America over the past 50 years (Dugan et al. 2017; Dugan et al. 2020). In this special issue, the group presents their most recent findings in a series of three original papers: (1) Dugan and Rock (2021) model increasing salinity in a distinctive groundwater fed seepage lake located next to a highway in Northern Wisconsin. By adjusting an outdated box model (Bowser 1992) to account for increasing Cl− reservoirs in the soil, the authors demonstrate why previously predicted 2020 Cl− concentrations in Sparking Lake were surpassed by 50%, highlighting the need to consider soil as a long-term reservoir of salt. (2) In a second paper, they demonstrate how Lake Michigan annually receives more than 1 million metric tonnes of Cl− from five main urbanized rivers (i.e., the Grand, St. Joseph, Fox, Kalamazoo, and Milwaukee Rivers, Dugan et al. 2021). If these trends continue, they predict that Lake Michigan could reach 18 mg L−1 Cl− by 2050, a concentration known to decrease reproduction and increase mortality of Daphnia for lakes within the Canadian Shield (Arnott et al. 2020). (3) Ladwig et al. (2021) investigate the understudied impact of increasing lake salinities on lake depth stratification for north temperate lakes. They show delays in spring turnover, prolonged summer stratification periods, and increases in water column stability during spring, summer, and winter, which could have critical impacts like anoxic conditions in the hypolimnion during summer. Impacts of increasing dissolved salts extend to muddled lake deltas that may once have persisted as unique ecosystems (Richardson et al. 2021). The associated complexity of salt impacted streams, ponds, and wetlands are covered in a series of three SI papers by Shattuck et al. (2022); Bolotin et al. (2022); and Kinsman-Costello et al. (2022). Decades of data are needed to understand prolonged salinity trends in stream surface waters outside of seasonal hydrologic variability. Shattuck et al. (2022) used long-term data for New Hampshire streams combined with insights from high-frequency sensors (15-min intervals) to elucidate influences of groundwater Cl− sources and extreme flooding events. Chloride concentrations increased threefold since 1953 in an urban site, and urban streams often exceed relatively lax (230 mg L−1) chronic chloride guidelines in all seasons, but surprisingly an extreme flood event reset Cl− levels for up to a decade. Bolotin et al. (2022) provide a predictive salinity classification model based on key drivers (e.g., precipitation, slope, and soil salinity), which may help managers track salinity across and within basins of the central and western US. Predictive modeling characterizing stream salinization patterns are needed across the globe to use as reference and management tools. Kinsman-Costello et al. (2022) provide an important review of salinization syndrome impacts on urban wetlands. They identify a knowledge gap that limits our understanding of how urban wetland salinization impacts biogeochemical processing (e.g., N & P nutrient removal) in urban wetlands, which is an ecosystem service that many urban wetlands are designed to perform. Most research on trends in freshwater salinization focuses on inland freshwater ecosystems such as rivers (Cañedo-Argüelles et al. 2013; Kaushal et al. 2022) and lakes (Dugan et al. 2017). However, coastal ecosystems also face severe salinization due mainly to a combination of water withdrawal—for irrigation and human consumption—and sea-level rise (Oude Essink et al. 2010; Mahmuduzzaman et al. 2014; Dasgupta et al. 2015; Mabrouk et al. 2018). To elucidate problems facing sensitive groundwater dependent coastal ecosystems in the Pacific and beyond, Dulai et al. (2021) use Hawaii as a case study to show how changes in groundwater nutrient and salinity discharge levels modify native marine macroalgal growth rates, branching patterns, and ostensibly weaken ensuing competitive interactions with invasive macroalgae. Tidal freshwater marsh communities are significantly affected by sea-level rise and seawater intrusion. Mobilian et al. (2020) conducted a large-scale, multiyear, field manipulation to address how in situ microbial community diversity and carbon cycling activity are more affected by the consistent press of seawater intrusion (i.e., by long-term sea-level rise—than by pulses of high salinity due to episodic seawater intrusion). Osburn et al. (2022) employed a laboratory experiment to understand the implications of what may happen at the mouth of coastal estuaries when toxic cyanobacterial blooms, such as those that occur in upstream eutrophic reservoirs, encounter salinity when they are flushed downstream to the ocean. Their results indicate that such practices may magnify the harmful effects of cyanobacterial blooms when they mix with ocean water. Changes in macroalgae and microbial communities along coastal salinity continua lead to predictable shifts in phytoplankton community diversity with a minimum diversity at intermediate salinity levels (i.e., at a salinity of 8 g L−1; Olli et al. 2022). However, when phytoplankton chlorophyll (Chl a) relative to total nitrogen was measured as an indicator of resource use efficiency (RUE), Olli et al. (2022) found functional redundancy in RUE likely due to fewer trophic interactions (i.e., lower resource competition and reduced grazing). We know that species occur within communities and ecosystems, and that the interaction between them can modulate the sensitivity of individual species to stressors (Baillard et al. 2020; Thompson et al. 2021). Kefford et al. (2021) and Arnott et al. (2022) call for more community-based toxicity tests and coordinated mesocosm studies that account for species interactions rather than single species toxicity tests performed in laboratories when salinity standards for the protection of aquatic ecosystems are developed. Results reported in this SI provide new knowledge about how lake and coastal ecosystems, zooplankton, plankton and microbial (algal, bacterial, and fungal) communities will likely respond to increasing salinity, not only with reductions in zooplankton abundance, but also with fewer species of zooplankton, and a consistent trophic shift towards primary producers and microbiota. Regional differences and high intra- and inter-specific variation in species responses to changing salinity are to be expected, and it may be difficult to link variable responses to drivers in multistressor environments. We conclude that the need to better understand lake and coastal salinization impacts on plankton communities will intensify with global climate change in most parts of the world (Jeppesen et al. 2015), and impacts will vary regionally. For example, in regions receiving large freshwater inputs from melting glaciers, salinity will decrease (Garcia-Eidell et al. 2019). In the search for solutions to FSS impacts, effective management practices that adjust for regional variability (e.g., calcium levels, additional contaminant pressures, changing climate and precipitation patterns) in ecosystem and community responses will help prevent costly impacts. The authors thank Jim Cloern, Gesa Weyhenmeyer, Steven Perez, and the Wiley editorial team for their vital and judicious assistance. The authors thank all the reviewers who graciously gave their time, expertise, and advice in helping review and improve special issue manuscripts. This study is part of the Global Salt Initiative, a working group formed during the Global Lake Ecological Observatory Network (GLEON) meeting held in 2017. The authors acknowledge the following funding sources for supporting our research, writing, and editing: Natural Sciences and Engineering Research Council (NSERC) Discovery Grant program (DG 03834-2015 to SJM and DG 05143-2016 to AMD). MC was supported by a Ramón y Cajal contract funded by the Spanish Ministry of Science and Innovation (RYC2020-029829-I). None declared.

Use of Rituximab in Childhood Idiopathic Nephrotic Syndrome

Abstract: Rituximab is an established therapy in children with idiopathic nephrotic syndrome to sustain short- to medium-term disease remission and avoid steroid toxicities. Recent trials focus on its use as a first-line agent among those with milder disease severity. Rituximab is used in multidrug refractory nephrotic syndrome and post-transplant disease recurrence, although the evidence is much less substantial. Available data suggest that the treatment response to rituximab depends on various patient factors, dosing regimen, and the concomitant use of maintenance immunosuppression. After repeated treatments, patients are found to have an improving response overall with a longer relapse-free period. The drug effect, however, is not permanent, and 80% of patients eventually relapse and many will require an additional course of rituximab. This underpins the importance of understanding the long-term safety profile on repeated treatments. Although rituximab appears to be generally safe, there are concerns about long-term hypogammaglobulinemia, especially in young children. Reliable immunophenotyping and biomarkers are yet to be discovered to predict treatment success, risk of both rare and severe side effects, e.g., persistent hypogammaglobulinemia, and guiding of redosing strategy. In this review, we highlight recent advances in the use of rituximab for childhood nephrotic syndrome and how the therapeutic landscape is evolving.

Thermo-bioconvection performance of nanofluid containing oxytactic microorganisms inside a square porous cavity under constant and periodic temperature boundary conditions

Abstract: Thermal performance of natural convection heat transfer of nanofluid containing oxytactic microorganisms saturated a square porous cavity under constant and sinusoidal temperature boundary conditions is numerically investigated. Scrutinizing the literature review reveals that microorganisms' impact on the rate of heat transfer may be contributory or destructive, depending on the problem under consideration. Accordingly, the objective of the current study is set to remove the detrimental effect of microorganisms on the average Nusselt number seen in some previous studies by applying a periodic temperature distribution on the sidewalls to introduce microorganisms as being an always heat transfer intensifier method. For this aim, the Buongiorno model is adopted to simulate the nanofluid flow and the Darcy model is employed to analyze the fluid flow inside porous media. By the definition of a series of appropriate dimensionless numbers, the governing equations are initially converted to a non-dimensional form of governing equations, and then, they are solved numerically using the FEM approach. The accuracy of the numerical method has successfully been validated by comparing it with the available study in the literature. Simulations are undertaken for different parameters including Rayleigh number, bioconvection Rayleigh number, bioconvection Peclet number, and bioconvection Lewis number. Obtained results are provided in the form of tabular and graphical contours related to streamlines, isothermal lines, isoconcentration of nanoparticles, oxygen, and microorganisms. Based on the outcomes, it is concluded that opposed to the constant wall temperature in which microorganisms’ presence leads to the Nusselt number attenuation for the majority of the considered cases, in sinusoidal temperature distribution, microorganisms lead to improvement of the heat transfer in all considered cases. These new findings will likely lead to revolutionary changes in the use of microorganisms in the heat transfer industry. Several applications exist for the concepts developed in this study, including cooling towers, microbial fuel cells, and nanotechnology-based bioconvection.

BERT4Loc: BERT for Location—POI Recommender System

Abstract: Recommending points of interest (POI) is a challenging task that requires extracting comprehensive location data from location-based social media platforms. To provide effective location-based recommendations, it is important to analyze users’ historical behavior and preferences. In this study, we present a sophisticated location-aware recommendation system that uses Bidirectional Encoder Representations from Transformers (BERT) to offer personalized location-based suggestions. Our model combines location information and user preferences to provide more relevant recommendations compared to models that predict the next POI in a sequence. Based on our experiments conducted on two benchmark datasets, we have observed that our BERT-based model surpasses baselines models in terms of HR by a significant margin of 6% compared to the second-best performing baseline. Furthermore, our model demonstrates a percentage gain of 1–2% in the NDCG compared to second best baseline. These results indicate the superior performance and effectiveness of our BERT-based approach in comparison to other models when evaluating HR and NDCG metrics. Moreover, we see the effectiveness of the proposed model for quality through additional experiments.

Inclusive education and deaf learners

Abstract: This chapter provides an overview of inclusive education for deaf learners with reference to how this concept has been differentially defined by deaf advocacy organizations and inclusion and special education advocates, and operationalized by governments. Inclusive education is often viewed in terms of disabled children's placement in a regular school. However, this focus on children's physical presence in the classroom frequently overlooks the issues of deaf children's participation and social and academic development. This article discusses some policy issues and problems with practical implementation and ideologies of inclusive schooling for deaf learners.

Proton exchange membrane (PEM) fuel cell parametric study via mathematical modeling and numerical simulation

Abstract: In the proton exchange membrane (PEM) fuel cell study, numerical analysis of complex and coupled multi-disciplinary processes involving the subjects of fluid dynamics, heat transfer, mass transport, and electrochemistry has been attempted over the past few decades. However, many resulting models are, in spite of fancier functionalities such as three-dimensionality, too complex to implement on account of the digital hardware requirement as well as computation time consumption. On the other hand, three-dimensional analytical models reported in literature look much simple, but they are embedded by a number of fairly unrealistic assumptions and, hence, lead to significantly weakened usability. In this thesis, a set of detailed two-dimensional non-isothermal computational models for PEM fuel cells in x-y and y-z planes are developed, which aims at the equivalency with the 3D PEM fuel cell model and, moreover, gains more insights with significantly reduced computational cost. The complete model consisting of the equations of continuity, momentum, energy, species concentrations, and electric potentials in different regions of a PEM fuel cell are numerically solved using the finite element method implemented into a commercial CFD (COMSOL) code. A comprehensive comparison with the experimental data has been performed to validate the 2D models developed in this study. On the basis of simulations of various flow and transport phenomena in an operational PEMFC, a systematic parametric study is conducted using the present developed PEM fuel cell models. A number of operating and design parameters are examined, including the operating pressure, ambient temperature, relative humidity, the porosity of the gas diffusion layer (GDL), the effective porosity of catalyst layer (CL), the porosity of membrane (M), the proton conductivity and the air inlet velocity at cathode side. The obtained results of this study revelaed that the membrane porosity, and air inlet velocity have considerable effects on the water content in the membrane, thus it is essential to select the proper values of these parameters to improve water management in the cell and avoid dehydration the membrane or flooding the electrode. Also, it is found that increasing air velocity at the inlet of the cathode gas channel has a significant effect on the temperature distribution in PEM fuel cell, as the temperature a noticeably dropped with higher inlet air velocity. The numerically results also found that with higher porosities of gas diffusion layers (GDLs) and catalyst layers (CLs), the performance of PEM fuel cell improved. In addition, it found that a higher performance can be achieved when fuel cell operated with reasonably higher operating temperature, operating pressure, proton conductivity and ensuring a full hydration of the reactants. The outcome of this study demonstrates that the present developed PEM fuel cell models can serve as a useful tool for understanding of transport and electrochemical phenomena in PEM fuel cell as well as for optimization of cell design and operating conditions.

Consumption of trematode parasite infectious stages: from conceptual synthesis to future research agenda

Abstract: Given their sheer cumulative biomass and ubiquitous presence, parasites are increasingly recognized as essential components of most food webs. Beyond their influence as consumers of host tissue, many parasites also have free-living infectious stages that may be ingested by non-host organisms, with implications for energy and nutrient transfer, as well as for pathogen transmission and infectious disease dynamics. This has been particularly well-documented for the cercaria free-living stage of digenean trematode parasites within the Phylum Platyhelminthes. Here, we aim to synthesize the current state of knowledge regarding cercariae consumption by examining: (a) approaches for studying cercariae consumption; (b) the range of consumers and trematode prey documented thus far; (c) factors influencing the likelihood of cercariae consumption; (d) consequences of cercariae consumption for individual predators (e.g. their viability as a food source); and (e) implications of cercariae consumption for entire communities and ecosystems (e.g. transmission, nutrient cycling and influences on other prey). We detected 121 unique consumer-by-cercaria combinations that spanned 60 species of consumer and 35 trematode species. Meaningful reductions in transmission were seen for 31 of 36 combinations that considered this; however, separate studies with the same cercaria and consumer sometimes showed different results. Along with addressing knowledge gaps and suggesting future research directions, we highlight how the conceptual and empirical approaches discussed here for consumption of cercariae are relevant for the infectious stages of other parasites and pathogens, illustrating the use of cercariae as a model system to help advance our knowledge regarding the general importance of parasite consumption.

Green Biodegradable Polylactide-Based Polyurethane Triblock Copolymers Reinforced with Cellulose Nanowhiskers

Abstract: A novel series of biodegradable polylactide-based triblock polyurethane (TBPU) copolymers covering a wide range of molecular weights and compositions were synthesized for potential use in biomedical applications. This new class of copolymers showed tailored mechanical properties, improved degradation rates, and enhanced cell attachment potential compared to polylactide homopolymer. Triblock copolymers, (TB) PL-PEG-PL, of different compositions were first synthesized from lactide and polyethylene glycol (PEG) via ring-opening polymerization in the presence of tin octoate as the catalyst. After which, polycaprolactone diol (PCL-diol) reacted with TB copolymers using 1,4-butane diisocyanate (BDI) as a nontoxic chain extender to form the final TBPUs. The final composition, molecular weight, thermal properties, hydrophilicity, and biodegradation rates of the obtained TB copolymers, and the corresponding TBPUs were characterized using 1H-NMR, GPC, FTIR, DSC, and SEM, and contact angle measurements. Results obtained from the lower molecular weight series of TBPUs demonstrated potential use in drug delivery and imaging contrast agents due to their high hydrophilicity and degradation rates. On the other hand, the higher molecular weight series of TBPUs exhibited improved hydrophilicity and degradation rates compared to PL-homopolymer. Moreover, they displayed improved tailored mechanical properties suitable for utilization as bone cement, or in regeneration medicinal applications of cartilage, trabecular, and cancellous bone implants. Furthermore, the polymer nanocomposites obtained by reinforcing the TBPU3 matrix with 7% (w/w) bacterial cellulose nanowhiskers (BCNW) displayed a ~16% increase in tensile strength, and 330% in % elongation compared with PL-homo polymer.

Plato the Novelist: The Family Saga in <i>Republic</i> 8–9

Abstract: In Republic 8–9, Socrates explains how the kallipolis develops into a series of flawed regimes. Each regime is said to have a corresponding soul type; these souls are described as a lineage of fathers and sons. Socrates, then, narrates not only a political story, but what is in effect a multigenerational family saga: the story of a moral decline and fall over the course of five generations, set amidst political turmoil and revolution, covering roughly a century of narrative ground from its start in tragicomedy to its end in disaster. What are the implications of this choice to convey the change from kallipolis to tyranny through such an emotionally charged narrative? As a hybrid of generic conventions, the family saga suggests Plato’s view that existing cultural models were insufficient for understanding and reacting to constitutional breakdown. I consider two accounts Socrates offers for the relationship between his family and political narratives, discussing the interpretive difficulties raised by each, and proposing that these difficulties oblige the reader to attend closely to the details of character and plot in Socrates’s story. I treat the family saga less as an explanation of constitutional breakdown than as an affective model that attempts to make such a breakdown emotionally vivid—one that is nevertheless consistent with the Republic’s strict limits on imitative poetry. Finally, I consider the kinds of political action that the family saga might motivate in the Republic’s readers, under three sets of assumptions about Plato’s attitudes toward Athenian democracy and the kallipolis.

Branded Bodies: Judicial Torture, Punishment, and Infamy in Nineteenth-Century Iran

Abstract: Abstract Forced branding, tattooing, and bodily inscriptions were linked to a complex intersection of meanings and uses in nineteenth-century Iran. Drawing on insights from studies of bodily inscriptions in other world historical contexts, this paper discusses branding as a marker of ownership, both of human slaves and of animals; Islamic attitudes toward bodily inscription and its symbolic significance in the afterlife; and associations between branding and human or divine love in Persian poetry. From this semiotic foundation, it turns to judicial uses of branding in nineteenth-century Iran: as torture for the extraction of incriminating admissions, and as punishment intended to shame (symbolically casting the criminal from society, stigmatizing their crime) and identify (tracking convicted criminals). Throughout the paper, branding’s legal place is understood in relation to silence and speaking, writing and reading, pain, humiliation, and the inversion of branding’s meaning by its victims, in Iran and a number of other societies.

Information-assisted volume rendering and visual evaluation through machine intelligence

Abstract: Exploration and visualization of complex data has become an integral part of life. But there is a semantic gap between the users and the visualization scientists. The priority of the users is usability while that of the scientists is techniques. Information-Assisted Visualization (IAV) can help bridge this gap, where additional information extracted from the raw data is presented to the user in an easily interpretable way. This thesis proposes some novel machine intelligence based systems for intuitive IAV. The majority of the thesis focuses on Direct Volume Rendering, where Transfer Functions (TF) are used to color the volume data to expose structures. Existing TF design methods require manipulating complex widgets, which may be difficult for the user. We propose two novel approaches towards TF design. In the data-centric approach, we generate an organized representation of the data through clustering and provide the user with some intuitive control over the output in the cluster domain. We use Spherical Self-Organizing Maps (SS)M) as the core of this approach. Instead of manipulating complex widgets, the user interacts with the simple SSOM color-coded lattice to design the TF. In the image-centric approach, the user interaction with the data is direct and minimal. The user interactions create the training data, and supervised classification is used to generate the TF. First, we propose novel supervised classifiers that combine the local information available through Support Vector Machine-based classifiers and the global information available through Nonparametric Discriminant Analysis-based classifiers. Using these classifiers, we propose a TF design method where the user interacts with the volume slices directly to generate the output. Finally, we explore the use of IAV for home-based physical rehabilitation. We propose an information-assisted visual valuation framework which can compare a user’s performance of a physical exercise with that of an expert using our novel Incremental Dynamic Time Warping method and communicate the results visually through our color-mapped skeleton silhouette. All the proposed techniques are accompanied by detailed experimental results comparing them against the state-of-the-art. The results shows the potential of using machine learning techniques to achieve visualization tasks in a simpler yet more effective way.

Interactions of Population, Health, and Place in a Spatially Explicit Heat Vulnerability Assessment

Abstract: <p>Urban sprawl and growth has experienced increased concern in geographic and environmental literature. Preceding the existence of robust frameworks found in regional and urban planning, as well as urban geography and economics, the spatial properties of allocation of urban land use are still far from being completely understood. This is largely due to the underlying complexity of the change found at spatial level of urban land use, merging social, economic and natural drivers. The spatial patterns formed, and the connectivity established among the different subsets of landuse types, becomes a complex network of interactions over time, helping to shape the structure of the city. The possibility to merge the configuration of land-use with complex networks may be assessed elegantly through graph theory. Nodes and edges can become abstract representations of typologies of space and are represented into a topological space of different land use types which traditionally share common spatial boundaries. Within a regional framework, the links between adjacent and neighboring urban land use types become better understood, by means of a Kamada-Kawai algorithm. This study uses land use in Lisbon over three years, 1990, 2000 and 2006, to develop a Kamada-Kawai graph interpretation of land-use as a result of neighboring power. The rapid change witnessed in Lisbon since the nineties, as well as the availability of CORINE Land Cover data in these three time stamps, permits a reflection on anthropogenic land-use change in urban and semi-urban areas in Portugal’s capital. This paper responds to (1) the structure and connectivity of urban land use over time, demonstrating that most of the agricultural land is stressed to transform to urban, gaining a central role in future. (2) Offer a systemic approach to land-use transitions generating what we call spatial memory, where land use change is often unpredictable over space, but becomes evident in a graph theory framework, and (3) advance in the geovisual understanding of spatial phenomena in land use transitions by means of graph theory. Thus, the structure of this combined method enables urban and landscape to have a better understanding of the spatial interaction of land-use types within the city, promoting an elegant solution to rapid geovisualization for land-use management in general. </p>

Organic chemistry synthesis problem as artificial intelligence planning

Abstract: This thesis formulates organic chemistry synthesis problems as Artificial Intelligence planning problems and uses a combination of techniques developed in the field of planning to solve organic synthesis problems. To this end, a methodology for axiomatizing organic chemistry is developed, which includes axiomatizing molecules and functional groups, as well as two approaches for representing chemical reactions in a logical language amenable to reasoning. A novel algorithm for planning specific to organic chemistry is further developed, based on which a planner capable of identifying 75 functional groups and chemical classes is implemented with a knowledge base of 55 generic chemical reactions. The performance of the planner is empirically evaluated on two sets of benchmark problems and analytically compared with a number of competing algorithms. v

Improving the Accumulation of Gold Nanoparticles Using Ultrasound and Microbubbles to Enhance Radiation Therapy

Abstract: Gold nanoparticles have long been considered for use in conjunction with radiation therapy to enhance dose in a local tumor regions. However, limitation in cellular accumulation remains a hindrance for treatments to extend to clinical levels. Ultrasound and microbubbles have been shown to enhance the delivery of chemotherapies, genetic material and other molecules. This goal of this study was to demonstrate, for the first time to the best of our knowledge, the increase in PEGylated gold nanoparticle accumulation in cells due to the addition of ultrasound and microbubbles, and survival fraction. The results display approximate 3 fold increase in intracellular gold content independent of nanoparticle size, resulting in a 5 fold increase in cell death. Additionally, it was shown that USMB can facilitate nuclear localization of gold nanoparticles with nuclear localized signals to further enhance radiation therapy.

Land-Use and Land Cover Change: Advancing with Geographic Information Science

Abstract: The physical size of the province of Ontario has been a limitation in assessing, compiling, and monitoring land-use and land cover change. Nevertheless, several regional and urban planning efforts and present and past initiatives have allowed the gathering of an ample amount of land-use data that should be examined from a spatial perspective. Further to the ongoing initiatives and the challenges of land-use classification at the provincial level, this chapter analyzes the available data sources. Additionally, a historical overview renders the limitations of land-use classifications and offers an ex ante vision of the potential of volunteered geographic information. Other data sources provide land cover analysis for Ontario while recognizing the importance of these data sources for planning, but also identifying the limitations in the classification of land use in peri-urban and rural areas.

Missing and Misrepresented: Portrayals of Other Ethnic and Racialized Groups in a Greater Toronto Area Ethnocultural Newspaper

Abstract: The vibrant ethnocultural press in the Greater Toronto Area is a testament to the multicultural reality of a metropolitan area where visible minorities are expected to be the majority by 2031. The GTA’s ethnocultural and racialized communities are served by more than 200 newspapers, many of them published in languages other than English or French. What role do these publications play in shaping how ethnic and racialized groups “see” each other? This case study examines how other groups are portrayed in the Chinese-language daily newspaper Ming Pao. With the exception of members of the White community, it concludes that other racial and ethnic groups are represented only to a limited extent and that, in some cases, they are also misrepresented.

The Canadian news directors study: demographics and political leanings of television decision makers

Abstract: Abstract: This is the first academic study to attempt to understand more about the men and women who make key decisions in television newsrooms across Canada. The authors surveyed all television news directors across the country. The research reveals that, unlike in the United States, the voting patterns of news directors mirror those of the general Canadian population. It reveals that news directors are more secular than those in the general population. The research also uncovered significant demographic differences between CBC and private sector news directors. Finally, it suggests that women and ethnic minorities are dramatically underrepresented in senior positions.

Optimal Replacement, Retrofit, and Management of a Fleet of Assets Under Regulations of an Emissions Trading System

Abstract: This thesis presents the development of a model for parallel replacement and improvement for a fleet of assets to minimize both the economic costs and greenhouse gas (GHG) emissions where the emissions are limited by cap-and-trade. The firm which owns the assets has the options of using the assets, putting them in inventory, improving them, or salvaging them. Different technological types and their performances have been considered for assets. The firm has the option of purchasing new assets from varying technologies and/or improving its existing assets to a higher-performance type. Moreover, the model considers the possibility of both banking the emission allowances and trading them in the market. The model was later used with data of a fleet of excavators in Ontario, Canada. The use of this model could help emitter firms to simultaneously manage the emissions and costs of their fleet of assets in a jurisdiction regulated by cap-and-trade.

Dynamic Finite Element Modelling and Free Vibration Analysis of Delaminated Composite Beams

Abstract: The requirement for accurate analysis tools to predict the behaviour of delaminated composites has grown and will continue to grow into the future, due to the high demand of these materials on major structural components. In the following, a detailed analysis of single- and double-delaminated beams is made, using traditional finite element techniques, as well as two dynamic element-based techniques. The Dynamic Stiffness Matrix (DSM) and Dynamic Finite Element (DFE) techniques introduce the concept of frequency-dependent stiffness matrices and shape functions, respectively, and have been documented to exhibit excellent convergence qualities when compared to traditional finite elements. Current trends in the literature are critically examined, and insight into different types of modeling techniques and constraint types are introduced. In particular, the continuity (both kinematic and force) conditions at delamination tips plays a large role in each model’s formulation. In addition, the data previously available from a commercial finite element suite are also utilized to validate the natural frequencies of the systems analyzed here. Beam element-based techniques are used and the results are compared to those obtained using the dynamic element techniques and data from the literature. In each case excellent agreement between different techniques was observed. Finally, general concluding remarks are made on the usefulness of the presented theories, and some comments are made on the future work of this research path.

Exploring the role of Black feminist thought in pre-service Early Childhood Education: on the possibilities of embedded transformative change

Abstract: <p>As a Black feminist scholar who teaches in an early childhood studies program, the author has witnessed how dominant theories and methods used for pre-service early childhood education and care disconnect students from their lived experiences. The detachment of social location in theoretical text, and particularly in developmental discourse, is not isolated to the field; it is instead a result of the fragmentation of knowledge, which is central in the modern colonial project. The author explores what the possibilities are for Black feminist scholarship in pre-service early childhood education and care while unpacking the many racial and intersecting injustices in the field. The dominant research and pedagogy practices in early childhood education and care have limitations, with omissions of the nuances of the critical engagement of students, families and community more broadly through lived experience. When assumptions of detached and ‘objective’ knowledge are centred, then ideas that challenge norms and the status quo are omitted or peripheralized, when they are included. The article explores the possibilities of what the author calls ‘embedded transformative change’ – a change that is central to pedagogy and research in the field of early childhood education and care as opposed to being placed at the margins. Through embedded transformative change, members of pre-service early childhood education and care programs can think of themselves as active agents in change and liberation.</p>

Energy and Latency Efficient Caching in Mobile Edge Networks: Survey, Solutions, and Challenges

Abstract: Future wireless networks provide research challenges with many fold increase of smart devices and the exponential growth in mobile data traffic. The advent of highly computational and real-time applications cause huge expansion in traffic volume. The emerging need to bring data closer to users and minimizing the traffic off the macrocell base station introduces the use of caches at the edge of the networks. Storing most popular files at the edge of mobile edge networks (MENs) in user terminals (UTs) and small base stations caches is a promising approach to the challenges that face data-rich wireless networks. Caching at the mobile UT allows to obtain requested contents directly from its nearby UTs caches through the device-to-device (D2D) communication. In this survey article, solutions for mobile edge computing and caching challenges in terms of energy and latency are presented. Caching in MENs and comparisons between different caching techniques in MENs are presented. An illustration of the research in cache development for wireless networks that apply intelligent and learning techniques in a specific domain in their design is presented. We summarize the challenges that face the design of caching system in MENs. Finally, some future research directions are discussed for the development of cache placement and cache access and delivery in MENs.

Front Page Challenge: A case study examining what the ethnic media promises and what it delivers

Abstract: The editors and publishers of ethnic newspapers acknowledge the importance of reporting local news in helping their readers understand Canadian society. Yet detailed analyses of news content produced by ethnic media organizations often find that information that fosters understanding of life in Canada takes second place to news from the group‟s home country. This study investigates the local news content published about the Greater Toronto Area in the Chinese-language newspaper Ming Pao(Toronto-area edition) and identifies a significant imbalance in the mix of local news versus homeland news from China, Taiwan, and Hong Kong. The author argues that newcomers trying to understand their adopted place would benefit from access to more extensive and varied local news and suggests that providing journalists who work in ethnic news media with greater opportunities for professional development would be one way to achieve this goal. Programs could include journalism skills workshops as well as seminars that explore the role of local news in helping immigrants adapt. Professional development sessions would also bring together journalists from different ethnocultural communities to discuss the challenges they face, develop joint projects, and acquaint editors and publishers with the latest research on the role of local news in fostering intercultural understanding.

When do people lie, for whom, and why? : Altruistic lying in an alibi corroboration context

Abstract: Three studies were conducted in order to identity factors that impact the likelihood that a witness will lie for a suspect in an alibi corroboration context. Specifically, the level of affinity between a suspect and a witness, the level of social pressure, and gender were investigated as factors impacting the likelihood that a witness would knowingly support a false alibi. During a study session purportedly intended to investigate dyadic problem-solving ability, a mock theft was staged in an adjacent office. When questioned by the experimenter, undergraduate students were provided the opportunity to either corroborate or refute a confederate’s false alibi that the latter had been in the testing room during the time of the theft, which participants knew was false. In study 1, participants who were explicitly asked to conceal the confederate’s whereabouts during the time of the theft were more likely to lie for him or her by corroborating the false alibi (61% vs. 26% of those who were not asked to lie). In study 2, there was a higher percentage of male participants who corroborated a male confederate’s false alibi (41%) compared to female participants who corroborated a female confederate’s false alibi (23%). In study 3, participants were found to be more likely to lie for a confederate when the latter was their friend (41%) than when he or she was a stranger (18%). How much a participant liked the suspect (study 1) and whether or not the suspect had previously helped the participant (study 2) did not affect the rates of false alibi corroboration. The results confirm that alibi witnesses often lie, but suggest that investigators and jurors may underestimate the frequency with which strangers and acquaintances lie for one another, and that witnesses who lie do so more often because they trust that the suspect is innocent rather than guilty.

Real Time Optimal Control of Distributed-Parameter Systems

Abstract: An optimal state feedback control strategy is proposed for processes described by non-linear, distributed-parameter models. For different values of a given parameter susceptible to upsets, the strategy involves off-line computation of a repository of optimal open-loop control, state, and the gain needed for the feedback adjustment of control. The gain is determined by minimizing the perturbation of the objective functional, state and control due to an upset. When an upset is encountered in a running process, the repository is utilized to obtain the control adjustment required to steer the process to the new optimal state. The strategy is successfully applied to a highly non-linear, heavy oil recovery process with the state depending non-linearly on time and two spatial directions inside a moving boundary, and subject to pressure upsets. The results demonstrate that the proposed strategy is able to determine control adjustment with negligible time delay, and navigate the process to the new optimal state when disturbed by a pressure upset.

Metrics and analytics in the newsroom: an ethnographic study exploring how audience data are changing journalistic practice

Abstract: <p>The use of metrics and analytics is now embedded in and directly impacting newsroom practice and routines. As audience data are used to shape and promote content that help form societal narratives, development of best practice is crucial, not only to enhance fulsome public discourse but as a means of reputation building for media outlets fighting to retain relevance and public trust, both of which are intrinsically tied to revenue and/or funding. This thesis explores the potential conflicts between journalism’s mandate to keep the public informed through quality, contextualised news coverage and the use of metrics and analytics to build scale and a sustainable business model. Empirical research is based on ethnographic observation in four news organisations on two continents in three different countries: Norway’s national broadcaster, NRK, which has developed its own analytics system that uses both qualitative and quantitative data; The Canadian Press, Canada’s national news agency, which is exploring ways to track how its content is being used with little direct access to audience data; The Hamilton Spectator, a local newspaper in Canada making the shift from print to digital; and a similarly sized and situated local paper in the United Kingdom, The Bournemouth Daily Echo. Participant observation and interviews were used to investigate how metrics and analytics impact newsroom routines; how journalists feel their work is impacted by the use of audience data; and how practices pertaining to the use of metrics and analytics are challenging the boundaries of journalism. The thesis employs a bricolage of theories within a sociological framework, through the lens of media logic, and draws on the author’s own perspective of working in a newsroom and, currently, in an academic media faculty. The research provides observed examples of the ways in which changing boundaries are impacting definitions of journalism and who is a journalist; it proposes best practice for the use of metrics and analytics in newsrooms that might better situate media outlets to serve their communities and survive in a rapidly changing media landscape; it offers suggestions for media scholars on best practice to perform research that better reflects newsroom routines particular to the use of metrics and analytics; the thesis contributes a new gatekeeping model that identifies two primary channels related specifically to the use of metrics and analytics: promotional and developmental; finally, the thesis demonstrates how a bricolage of complementary theories and the selection of multiple sites of study might best support the reflexive investigation of complex social structures within a rapidly changing field.<br> </p>

Neither Temporary, Nor Permanent: The Precarious Employment Experiences of Refugee Claimants in Toronto

Abstract: <p>While Canada’s immigration system is shaped primarily by the nation’s economic needs, refugee claimants’ motivations are, by nature, non-economic. Resultantly, refugee claimants are often portrayed as a drain on Canadian resources. Despite this however, refugee claimants’ employment experiences remain underrepresented in the literature. This study explores the employment experiences of refugee claimants in Toronto, and finds that claimants face distinct and unique barriers stemming from their precarious legal status. Additionally, as neither temporary workers nor permanent citizens, this study finds that refugee claimants perceive employment as an integrative expression of belonging and citizenship. Through the lens of <em>refugeeness</em>, this study traces the subjective employment trajectories of refugee claimants. Findings indicate that refugee claimants’ employability is shaped by real and ascribed barriers associated with their citizenship status, creating decidedly unique and often difficult employment experiences.</p>

A Virtual Reality Investigation of Spontaneous Navigation Strategies and Spatial Memory Performance in Schizophrenia

Abstract: There is strong evidence that schizophrenia (SCZ) patients perform poorly on spatial memory tasks. We investigated whether these deficits were associated with subdivisions of spatial memory (locale/cognitive map and taxon/response) or whether these deficits represented a general cognitive decline. This study investigated the types of spontaneous navigation strategies used by individuals living with SCZ to solve the 4 on 8 task. It was predicted that SCZ participants who spontaneously chose a spatial strategy would have the longest latencies and make the most errors. Four of five measures of latency and errors produced a medium magnitude effect size (