82837 research outputs found
Sort by
Diversification of annual cropping sequences with perennial forage seed crops
No full textIdentifying profitable cropping systems from a sustainable perspective is crucial for addressing the challenges faced in modern farming. A truly sustainable cropping system can ensure farm profitability, promote environmental stewardship, and advance social equity. In this study, we explored the potential of cropping system diversification as a strategy to achieve the sustainability goals. We hypothesized that integrating perennial forage seed crops into cropping systems would increase productivity and profitability while enhancing soil and environmental health. To test this, a field study was initiated in 2013 at Beaverlodge Research Farm, Agriculture and Agri-Food Canada, Alberta to identify beneficial cropping systems. The experiment was laid out in a split plot design randomized complete block design with four replicates. Eight different cropping sequences were considered main-factor treatments and three nitrogen levels (0, 45, 90 kg ha-1) were assigned in sub-plots. The cropping sequences included four annual crops (canola [Brassica napus L.], wheat [Triticum aestivum L.], pea [Pisum sativum L.], and barley [Hordeum vulgare L.]), three perennial grasses (creeping red fescue [Festuca rubra L.], meadow bromegrass [Bromus riparius Rehm.], and timothy [Phleum pratense L.]), and two perennial legumes (alsike clover [Trifolium hybridum L.], and red clover [Trifolium pratense L.]). Among the eight cropping sequences treatments, six were diversified with both perennial forage legumes and grasses to compare with annual-based traditional sequences. The productivity of the cropping system was evaluated based on seed yield and expressed as canola equivalent yield (CEY), while gross revenue and gross margin were used as profitability metrics for uniform comparison among the tested sequences. Soil samples were collected from 0-15 cm depth over short- and long-term periods to assess soil physical, chemical, and biological properties that are sensitive to change with cropping system diversification. The CEY, gross revenue, and gross margin were notably higher in the legume to vernalizing grass rotation, regardless of nitrogen fertility level. The higher seed price of the perennial legume (red clover) and the higher seed yield and price of the vernalizing grass (meadow bromegrass) during their production phases provided an opportunity to capitalize on favorable seasonal weather and local market demands. However, the aboveground biomass yield was significantly higher in annual cropping sequences and improved with increasing nitrogen rates as compared to perennial forage-based sequences. Soil health indicators such as soil organic carbon, microbial biomass carbon, active carbon, and the activities of carbon and nitrogen cycling enzymes were significantly improved with the inclusion of perennial forages in annual cropping systems. Specifically, the creeping red fescue dominated cropping sequence exhibited higher soil aggregate stability and structural resilience as compared to other sequences. However, soil compaction, bulk density, pH, water infiltration rates, and water content at field capacity showed no significant differences among cropping sequences tested in this study. In summary, the perennial forage seed crops-based cropping system can be adopted to optimize farm profits while improving soil health under soil-climatic conditions similar to those of the Peace River region in western Canada
Supplementary File 1 Raw DIA intensity values and processed data used to identify proteins with altered stability across conditions
No full textHsp90 is an essential molecular chaperone that plays a key role in maintaining protein homeostasis by assisting the folding, activation, and maturation of diverse client proteins. Hsp90 functions through a dynamic conformational cycle that is coupled to ATP hydrolysis. Its ATP driven conformational cycle is finely regulated by post translational modifications and a network of co chaperones. Among these regulators, Accelerator of Hsp90 ATPase 1 (Ahsa1) is the most potent stimulator of Hsp90 ATPase activity, yet its mechanistic role in metazoans, and its potential Hsp90 independent functions, remain incompletely understood. This thesis dissects the biochemical and cellular functions of a conserved 20-residue N-terminal segment of Ahsa1, termed the intrinsic chaperone domain (ICD), and evaluates Ahsa1-dependent proteome turnover. Quantitative ATPase assays, structure guided mutagenesis, and cell based co immunoprecipitation revealed that removing the ICD accelerates Hsp90 ATPase activity in vitro and impairs stable Ahsa1–Hsp90 recruitment in cells. Surprisingly, this region has also recently been shown to contribute to an Hsp90-independent chaperone role. The work here also demonstrates that the NxNNWHW motif is also essential in the mammalian protein function, revealing key differences and similarities in yeast and metazoan protein. To probe cellular roles of Ahsa1, a novel proteome wide bioorthogonal non-canonical amino acid tagging (BONCAT) pulse chase workflow was performed to measure in cell protein degradation kinetics. BONCAT profiling showed that Ahsa1 knock down modestly destabilises a select set of proteins, whereas over expression, especially of the ICD deleted variant, reshapes the half lives of hundreds of proteins, including factors beyond the canonical Hsp90 client repertoire. These data, coupled with in vitro holdase assays, support dual Hsp90 dependent and autonomous activities for Ahsa1. The study has also uncovered previously unappreciated roles for Ahsa1 in signalling and innate immune pathways. Together, these findings expand the current understanding of co-chaperone function by revealing new structural and functional roles for Ahsa1 in proteome maintenance. This work introduces BONCAT pulse chase proteomics as a powerful tool for studying chaperone mediated proteome dynamics and advancing understanding of co chaperone biology
Extrafloral nectaries in aspen (Populus tremuloides) and their possible role as a sink tissue for non-structural carbohydrates
No full textTrembling aspen (Populus tremuloides Michx.) is a deciduous clonal species that is commonly found across North America, mainly in boreal and aspen parkland regions. This species possesses extrafloral nectaries (EFNs), which are purported to exude sugars to attract insect predators, but may also have other functions, including the potential as a sink tissue for non-structural carbohydrates (NSC). To determine whether aspen preferentially use extrafloral nectaries to store starches and sugars, I set up two separate experiments. In the first experiment, I attempted to girdle the phloem of trees below their canopy to prevent the trees from sending NSC to their roots. I then collected leaves with EFNs on days two, six and ten afterwards. I found that over the collection period, sugar concentrations of leaf tissue decreased and starch concentrations increased for both girdled and ungirdled trees. In EFNs, sugar concentrations decreased faster in girdled than control trees. However, no statistical differences in NSC were found at each time-point, between girdled and control aspen. It is unclear if there was complete removal of all of the phloem from every tree in the “Girdled” group, which may have affected final results. Natural seasonal senescence likely also had an effect on the sugar and starch concentrations in the leaves and EFN tissue. The second experiment involved restricting rainfall for seed-origin aspen trees by excluding precipitation with tarps. I hypothesized that if aspen used EFNs to redistribute NSC, and reduced soil moisture causes a potential build-up of sugars in aspen tissues, then tarped trees should produce more EFN-bearing leaves compared to untarped trees. I tarped the ground around ten young aspen trees from mid-May to mid-September, 2023, each paired with another aspen, left untarped. At the end of the season, the trees were completely defoliated by hand. I found no statistical difference in the number of EFN bearing leaves between tarped and untarped trees. However, the tarps were compromised in a major rainfall event which likely decreased their effect on soil moisture. Volumetric water content in soils was significantly different between the untarped and tarped trees on only one sampling date in mid-August, after the critical time for expression of EFNs in neo-growth had already passed. In conclusion, it did not appear that aspen trees use their EFNs as preferential sinks for NSC when the tree is girdled. My results did not show significant differences between EFN and leaf tissues in girdled trees when compared to control. Likewise, trees that had their roots tarped did not demonstrate phenotypic plasticity by increasing the number of EFNs in neo-growth. However, due to the potentially inadequate girdling of the phloem and the unusually high rainfall event during a critical growth period, my results may have been affected and do not reflect what was expected in my hypothesis. The trees did, however, use their EFNs as temporary stores but it was unclear if this was due to our manipulations or natural seasonal senescence
Structural Retention Harvesting and Small Mammal Biodiversity in Alberta’s Boreal Forests
No full textThe boreal forest is one of the largest terrestrial biomes globally, providing critical
ecosystem services, carbon storage, and habitat for diverse fauna, while supporting
economically important forestry industries. However, intensive forest management,
dominated by clear-cutting, has simplified stand structure, reduced coarse woody
debris, and diminished late-seral forest attributes, with documented negative effects
on species dependent on these conditions. In response to these concerns, forest
managers have increasingly adopted retention-based harvesting systems that aim
to emulate the structural legacies of natural disturbances while maintaining timber
yields. Two emerging approaches in Alberta are: stubbing (the deliberate creation
of high-cut stems during harvest while protecting the forest floor) and understory
protection (UP) harvesting (a practice that retains understory vegetation and select
overstory trees during partial harvesting). Despite their growing adoption in
operational forestry, their effectiveness in supporting small mammal biodiversity
remains insufficiently evaluated. Small mammals, given their fine-scale habitat
sensitivity, diverse ecological roles in seed dispersal, soil processes, and food webs,
and proven value as bioindicators, provide an ideal model group for assessing the
ecological outcomes of retention-based harvesting. In my first objective, I evaluated the ecological benefits of stubbing using a paired-block design comparing stubbing and adjacent clear-cuts across 67 blocks in
western Alberta’s foothill forests. Motion-triggered camera trap surveys revealed that
stubbing supported higher gamma richness and a greater presence of forest specialists
(Clethrionomys gapperi, Tamiasciurus hudsonicus) compared to clear-cuts, which
were dominated by generalists (Peromyscus maniculatus). Stubbing sites had greater
shrub cover and less bare ground. Species-specific responses were driven by downed
woody material (DWM) volume, decay stage, and grass cover: generalists such as
Peromyscus maniculatus preferred high volumes of late-decay woody material with
low grass cover, whereas Clethrionomys gapperi avoided high volumes of late-decay
material, possibly due to competition or predation risk.
In mysecondobjective, IassessedtheeffectivenessofUPharvestinginsupporting
old-forest-associated small mammals using a randomized block design across 57 sites
representing four treatments: natural disturbance harvesting (NDH), unharvested
old growth (OG), and two UP sub-treatments: structurally intact UP Buffer and
more exposed UP Trail. NDH and UP Trail, with reduced canopy cover, lower green
tree basal area, and elevated grass and shrub cover, favored early-seral specialists
and generalists, including Sorex shrews, Peromyscus maniculatus, Zapus princeps,
and Lepus americanus. In contrast, UP Buffer and OG sites, characterized by
late-seral structural conditions, supported higher habitat use intensity and occupancy
by old-forest specialists such as Clethrionomys gapperi, Glaucomys sabrinus, and
Tamiasciurus hudsonicus. Notably, the occurrence of Clethrionomys gapperi and G.
sabrinus was insensitive to harvest age, indicating that structural retention, rather
than stand age, was the primary driver of their presence.
Collectively, these findings demonstrate that both stubbing and UP harvesting can
maintain or enhance small mammal diversity in managed boreal forests by providing
habitat for species acrossarangeofseralstages. Stubbingoffersacost-effectivemeans
of increasing structural heterogeneity in clear-cuts, while UP harvesting, particularly through the incorporation of intact buffers, can accelerate the recovery of late-seral
habitat conditions. Integrating these retention-based strategies into operational
forestry can help balance timber production with biodiversity conservation, thereby
supporting a more ecologically resilient boreal forest landscape
Role of Pharmacists in Chronic Obstructive Pulmonary Disease Management
No full textBackground: Patient-centered medical homes (PCMHs) are foundational for integrated primary healthcare delivery and population health management. A key PCMH principle is chronic disease management, which requires collaboration among healthcare professionals to meet patients' medical and psychosocial needs. Chronic obstructive pulmonary disease (COPD) is well suited to benefit from collaborative care. The expanding role of pharmacists positions them as suitable for close collaboration in managing chronic diseases, including COPD. Pharmacists may contribute to COPD management through detecting adverse drug reactions, medication reconciliation, smoking cessation counseling, addressing treatment adherence, and inhaler technique assessment. Besides participating in case-finding activities including referral patients to spirometry, diagnosis, and treatment initiation. Objectives: Aim one is to map pharmacists' activities and collaboration between pharmacists and physicians, describe outcomes of pharmacist-physician collaborative care in COPD according to the Economic, Clinical, Humanistic Outcomes (ECHO) model. Aim two is to understand current COPD management practices by physicians and examine their perceptions of COPD clinical services provided by community pharmacists within Alberta.
Method: The first project was a scoping review that followed the methodological framework developed by Arksey and O’Malley. A comprehensive search from January 2003 to August 2024 was conducted using Scopus, MEDLINE, Web of Science, Embase, and the first 100 results of Google Scholar. The search strategy employed a combination of "pharmacist”, "COPD”, "collaboration", and "physician" concepts, incorporating MeSH terms and expanded free-text terms. The second project was an online cross-sectional survey conducted with a convenience sample of respirologists, emergency medicine, and family medicine physicians within Alberta between November 1st, 2023, to November 1st, 2024. The survey tool was developed by the authors based on previous literature. Results: In project 1, Most studies originated from the USA (n=11; 61%) and used observational research designs (n=15; 83%) to evaluate outcomes. Multi-component interventions were common and the main pharmacists’ activities were: 1) Medication optimization (n=16; 89%), 2) COPD monitoring (n=18; 100%), 3) Screening and diagnosis (n=4; 22%), and 4) Other activities (n=12; 67%). Integrated services were delivered by pharmacists co-located with physicians in 12 studies (67%); 8 (44.4%) studies scored high on collaboration scale (≥6 out of 10). The most commonly reported outcomes were clinical (n=11; 61%) particularly hospital-related outcomes, followed by humanistic (n=8; 45%) most commonly quality of life, and economic (n=7; 39%) primarily cost savings. In project 2, Of the 96 individual surveys returned, 52 were complete. The majority (n=38, 73.1%) had experience collaborating with pharmacists providing clinical services and 68% (n=26) of these rated pharmacist’s services as good or very good. Two-thirds of respondents (n=34; 66%) encounter 6 or more COPD patients/month. Patients had access to smoking cessation programs and required medications. Access to timely pulmonary rehabilitation; specialist referral and post-hospitalization assessment were viewed as inadequate. Eighty-one percent of physicians agreed that pharmacists have an important role in COPD care. Regarding assessment, most participants (n=36, 69%) agreed that pharmacists can inform physicians about the need for spirometry in those with suspected COPD, but only half (n=25, 48%) supported pharmacists performing spirometry in patients at risk. The majority agreed to items relating to pharmacist roles in patient and caregiver education. Regarding management, half of the respondents (n=25, 49%) agreed that pharmacists could assist with managing COPD exacerbations, while almost all (n=51, 98%) agreed that pharmacists can ensure COPD patients have up-to-date immunizations.
Conclusion: Using a scoping review and cross-sectional survey, this thesis explored the pharmacists’ activities in COPD care and the outcomes of these collaborative practices in addition to the perceptions of physicians about the care provided and the role of community pharmacists in COPD management. The findings highlighted considerable variability in pharmacist interventions, tailored to address diverse patient needs. Collaborative approaches involving physicians and pharmacists in COPD management may have a positive impact on both health-related and economic outcomes, although the impact on humanistic aspects remains inconsistent. Also, the results of the survey showed most respondents recognized that community pharmacists play an important role in patient education and ensure that treatment aligns with current evidence-based practices. However, physicians' perspectives varied and there was less support for pharmacists' capacity to contribute to the process of diagnosing patients with COPD. Most of the participating physicians believed that the majority of their patients had adequate access to the recommended care. Additional research is necessary to investigate physicians' views on pharmacists' roles in COPD management to support high-quality COPD care
Advancing therapeutic platforms through in situ drug production and release
No full textHere, I describe my efforts in building artificial cells that sense the presence of tumors and respond by releasing drug molecules. The artificial cells contain DNA that encode their function. In the final design, specific molecules will be sensed by aptameric sequences of DNA tethered to the surface of the lipid membrane of the artificial cells. In this design, the signal is transduced by the release of a membrane permeable small molecule that activates the expression of an enzyme and a protein pore. The enzyme converts an encapsulated prodrug to a drug that secretes from the artificial cell and kills the tumor. The system was optimized by screening the efficiency of transcription-translation of different genetic constructs by fluorescence spectroscopy. The permeability of trigger molecules and the activity of the prodrug and drug were also evaluated. Ultimately, we hope that our integrated approach will create a versatile therapeutic platform capable of precisely identifying biomarkers and, in response, releasing drug molecules tailored to the specific ailment
Revisiting the Fuzzy Tiling Activation
No full textMany choices in deep reinforcement learning were inherited from deep supervised learning and largely remain unchanged. It is common to use fully connected feedforward neural networks---potentially first with convolutional layers---with rectified linear unit (ReLU) activations, standard initializations, and the Adam optimizer. It is hard to deviate from these defaults, because it can be hard to change just one component and maintain performance and similarly it can be hard to isolate and understand one component. In this work, we reconsider and study one of these choices: replacing ReLU with another activation, called the Fuzzy Tiling Activation (FTA). FTA is a one-to-many activation that was introduced previously to learn sparse activation patterns, and shown to be useful for improving stability in online reinforcement learning. But further investigation is needed. In this thesis, we show that FTA is at least as effective as ReLU and tanh across a range of problems, according to both performance and a set of reliability metrics, which we improve from earlier work. We then dive deeper into FTA's mechanism, showing that the ``fuzzy factor'' delivers superior performance to binary discretization and shedding light on when in learning FTA is most beneficial. We also find that FTA exhibits low hyperparameter sensitivity across problems, making it an easy-to-use alternative to standard practice. We conclude by showing that using FTA in an environment not typically found in benchmark suites significantly outperforms ReLU, suggesting that FTA can be effectively applied to new problems
Constraining the formation of Mg-clays in Mg-carbonate rich alkaline lakes
No full textCarbon sequestration processes such as silicate weathering and mineral carbonation have regulated atmospheric CO2 concentrations in natural systems over geologic time. Alkaline lakes have been highly studied given that their high pH and dissolved inorganic carbon concentrations yield to ideal carbon sequestration environments. Insights gained from studying natural alkaline environments where we observe carbon sequestering processes can be enhanced and implemented to engineered carbon sequestration projects. Broad implementation of carbon sequestration technologies is necessary in order to diminish the impacts of anthropogenic CO2 emissions and strive to reach carbon neutrality. While prior studies have explored the interactions between aqueous geochemistry, microbiology, and carbonate precipitation of alkaline lakes, the formation and impact of authigenic Mg-rich clays on these systems remains largely unexamined. Authigenic Al-poor Mg-clays play a crucial role in the geochemical cycling of alkaline lakes and are closely associated with carbonate minerals, influencing solution chemistry and carbonate precipitation. This thesis advances our understanding of the geochemical and biogeochemical processes governing authigenic mineral precipitation in alkaline lakes from the Cariboo Plateau, British Columbia using a combination of quantitative and qualitative X-ray diffraction techniques, Fourier transform infrared spectroscopy, scanning electron microscopy, sediment composition and aqueous geochemistry analyses. Chapter 2 identifies and characterizes the presence of stevensite as the main authigenic Mg-rich clay phase present in lacustrine sediment and microbial mat samples from four lakes in the Cariboo Plateau with varying geochemistry and alkalinities. Findings revealed that microbial processes appear to favour the formation of Mg-clays over Mg-carbonate precipitation, while Mg-carbonate minerals were higher in abundance in lacustrine sediments, suggesting that phototrophic microbial mats highly influence Mg-clay precipitation through processes such as photosynthesis, heterotrophy, and Si(aq) regulation by diatoms. These results further our understanding of conditions that favour Mg-clay formation, implying that precipitation of these minerals do not only rely on abiotic factors within the water column. Chapter 3 tests the hypothesis that Mg-clays can be a precursor for Mg-carbonate precipitation through a series of laboratory microbial and abiotic batch experiments. While synthetic stevensite [Na0.082Ca0.013·nH2O)Mg2.92Si4O10(OH)2] can dissolve and release Mg with the addition of acid, abiotic pH swing experiments led to re-precipitation of Mg-clays rather than carbonate formation, highlighting a challenge for CO₂ sequestration—termed here as "the silica problem". However, biological experiments using a phototrophic microbial consortium led to dypingite [Mg5(CO3)4(OH)2·~5H2O] precipitation on stevensite surfaces, suggesting that Mg-clays can act as precursors to Mg-carbonates. Results have important implications for the use of Mg-clays in carbon sequestration methods, such as enhanced rock weathering and microbial mineral carbonation. Chapter 4 analyzed the pore water geochemistry and sediment core mineralogy from Last Chance Lake. Results revealed that stevensite formation correlates with organic matter degradation, indicating a role for early diagenesis in Mg-clay precipitation in alkaline lakes. Findings from this study may have important implications for using authigenic minerals in lacustrine sediments as paleoenvironmental proxies. Chapter 5 investigated the relationships between aqueous geochemistry and authigenic mineralogy of 27 alkaline lakes and 11 playas from the Cariboo Plateau, British Columbia. Results were used to evaluate and calculate the impacts of reverse weathering on carbon sequestration efficiency of the alkaline lakes, highlighting the importance of including CO2 release by authigenic clay and carbonate precipitation into engineered carbon sequestration models and monitoring methods
The Girls Are a Single Body: Mediating Intersectional Feminism in Contemporary YA
No full textResponding to the recent surge in publications of realist young adult (YA) novels about feminism, this thesis examines the mediation of feminist politics in two exemplary case studies: Amy Reed’s YA rape novel, The Nowhere Girls (2017), and Renée Watson and Ellen Hagan’s activist coming-of-age narrative, Watch Us Rise (2019). These books emerge alongside ongoing debates about the extent to which cultural production—particularly texts created for young audiences—can proliferate disruptive, justice-oriented politics within a popular media culture underpinned by white, capitalist, and neoliberal logics. As such, this thesis considers how these case studies reconcile their explicit intersectional feminist commitments with the formal affordances of YA literature and the demands of popular culture. My analysis begins with an interrogation of how Reed, Watson, and Hagan focalize their novels’ feminist ideologies through the conventions of realist school stories. I then evaluate how the authors employ multivoiced narration to exercise their politics on the level of narrative structure. Finally, I investigate the possibilities and constraints of multimodal expressions of intersectional feminism in these novels. Taken together, these chapters find that, at times, The Nowhere Girls and Watch Us Rise engage in problematic popular feminist practices, including simplifying complex political discourses and maintaining attachments to visibility as a form of social action. Ultimately, however, this thesis concludes that the affordances of YA literature exhibited in these novels are uniquely positioned to express radical, intersectional politics within popular culture