Mount Allison University
  • Sackville, New Brunswick, Canada
Recent publications
This study characterizes single-particle aerosol composition from filters collected during the ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) and CLoud–Aerosol–Radiation Interaction and Forcing: Year 2017 (CLARIFY-2017) campaigns. In particular the study describes aged biomass burning aerosol (BBA), its interaction with the marine boundary layer and the influence of biomass burning (BB) air on marine aerosol. The study finds evidence of BBA influenced by marine boundary layer processing as well as sea salt influenced by BB air. Secondary chloride aerosols were observed in clean marine air as well as in BB-influenced air in the free troposphere. Higher-volatility organic aerosol appears to be associated with increased age of biomass burning plumes, and photolysis or oxidation may be a mechanism for the apparent increased volatility. Aqueous processing and interaction with the marine boundary layer air may be a mechanism for the presence of sodium on many aged potassium salts. By number, biomass burning potassium salts and modified sea salts are the most observed particles on filter samples. The most commonly observed BC coatings are inorganic salts. These results suggest that atmospheric processes such as photolysis, oxidation and cloud processing are key drivers in the elemental composition and morphology of aged BBA. Fresh BBA inorganic salt content, as it has an important role in the particles' ability to uptake water, may be a key driver in how aqueous processing and atmospheric aging proceed.
Biomass burning emissions often contain brown carbon (BrC), which represents a large family of light-absorbing organics that are chemically complex, thus making it difficult to estimate their absorption of incoming solar radiation, resulting in large uncertainties in the estimation of the global direct radiative effect of aerosols. Here we investigate the contribution of BrC to the total light absorption of biomass burning aerosols over the South-East Atlantic Ocean with different optical models, utilizing a suite of airborne measurements from the ORACLES 2018 campaign. An effective refractive index of black carbon (BC), meBC=1.95+ikeBC, that characterizes the absorptivity of all absorbing components at 660 nm wavelength was introduced to facilitate the attribution of absorption at shorter wavelengths, i.e. 470 nm. Most values of the imaginary part of the effective refractive index, keBC, were larger than those commonly used for BC from biomass burning emissions, suggesting contributions from absorbers besides BC at 660 nm. The TEM-EDX single-particle analysis further suggests that these long-wavelength absorbers might include iron oxides, as iron is found to be present only when large values of keBC are derived. Using this effective BC refractive index, we find that the contribution of BrC to the total absorption at 470 nm (RBrC,470) ranges from ∼8 %–22 %, with the organic aerosol mass absorption coefficient (MACOA,470) at this wavelength ranging from 0.30±0.27 to 0.68±0.08 m2 g−1. The core–shell model yielded much higher estimates of MACOA,470 and RBrC,470 than homogeneous mixing models, underscoring the importance of model treatment. Absorption attribution using the Bruggeman mixing Mie model suggests a minor BrC contribution of 4 % at 530 nm, while its removal would triple the BrC contribution to the total absorption at 470 nm obtained using the AAE (absorption Ångström exponent) attribution method. Thus, it is recommended that the application of any optical properties-based attribution method use absorption coefficients at the longest possible wavelength to minimize the influence of BrC and to account for potential contributions from other absorbing materials.
Conservation of mobile organisms is difficult in the absence of detailed information about movement and habitat use. While the miniaturization of tracking devices has eased the collection of such information, it remains logistically and financially difficult to track a wide range of species across a large geographic scale. Predictive distribution models can be used to fill this gap by integrating both telemetry and census data to construct distribution maps and inform conservation goals and planning. We used tracking data from 520 individuals of 14 seabird species in Atlantic Canada to first compare foraging range and distance to shorelines among species across colonies, and then developed tree-based machine-learning models to predict foraging distributions for more than 5000 breeding sites distributed along more than 5000 km of shoreline. Despite large variability in foraging ranges among species, tracking data revealed clusters of species using similar foraging habitats (e.g., nearshore vs. offshore foragers), and within species, foraging range was highly colony-specific. Even with this variability, distance from the nesting colony was an important predictor of distribution for nearly all species, while distance from coastlines and bathymetry (slope and ruggedness) were additional important predictors for some
Early career researchers (ECRs) are important stakeholders leading efforts to catalyze systemic change in research culture and practice. Here, we summarize the outputs from a virtual unconventional conference (unconference), which brought together 54 invited experts from 20 countries with extensive experience in ECR initiatives designed to improve the culture and practice of science. Together, we drafted 2 sets of recommendations for (1) ECRs directly involved in initiatives or activities to change research culture and practice; and (2) stakeholders who wish to support ECRs in these efforts. Importantly, these points apply to ECRs working to promote change on a systemic level, not only those improving aspects of their own work. In both sets of recommendations, we underline the importance of incentivizing and providing time and resources for systems-level science improvement activities, including ECRs in organizational decision-making processes, and working to dismantle structural barriers to participation for marginalized groups. We further highlight obstacles that ECRs face when working to promote reform, as well as proposed solutions and examples of current best practices. The abstract and recommendations for stakeholders are available in Dutch, German, Greek (abstract only), Italian, Japanese, Polish, Portuguese, Spanish, and Serbian.
Walgate and Scott have determined the maximum number of generic pure quantum states that can be unambiguously discriminated by an LOCC measurement [Journal of Physics A: Mathematical and Theoretical, 41:375305, 08 2008]. In this work, we determine this number in a more general setting in which the local parties have access to pre-shared entanglement in the form of a resource state. We find that, for an arbitrary pure resource state, this number is equal to the Krull dimension of (the closure of) the set of pure states obtainable from the resource state by SLOCC. Surprisingly, a generic resource state maximizes this number.Local state discrimination is closely related to the topic of entangled subspaces, which we study in its own right. We introduce r -entangled subspaces, which naturally generalize previously studied spaces to higher multipartite entanglement. We use algebraic-geometric methods to determine the maximum dimension of an r -entangled subspace, and present novel explicit constructions of such spaces. We obtain similar results for symmetric and antisymmetric r -entangled subspaces, which correspond to entangled subspaces of bosonic and fermionic systems, respectively.
Gold nanoparticles (AuNP) are promising anti-cancer agents because of their modifiable properties and high biocompatibility. This study used multiple parallel analyses to investigate the cytotoxic properties of 5 nm AuNP conjugated to four different ligands with distinct surface chemistry: polyethylene glycol (PEG), trimethylammonium bromide (TMAB), 4-dimethylaminopyridine (DMAP), and carboxyl (COOH). We used a range of biochemical and high-content microscopy methods to evaluate the metabolic function, oxidative stress, cell health, cell viability, and cell morphology in SKOV3 ovarian cancer cells. Each AuNP displayed a distinct cytotoxicity profile. All AuNP species assessed exhibited signs of dose-dependent cytotoxicity when morphology, clonogenic survival, lysosomal uptake, or cell number were measured as the marker of toxicity. All particles except for AuNP-COOH increased SKOV3 apoptosis. In contrast, AuNP-TMAB was the only particle that did not alter the metabolic function or induce significant signs of oxidative stress. These results demonstrate that AuNP surface chemistry impacts the magnitude and mechanism of SKOV3 cell death. Together, these findings reinforce the important role for multiparametric cytotoxicity characterization when considering the utility of novel particles and surface chemistries.
The use of drones fo r geophysical data acquisition and artificial intelligence (AI) for geophysical data processing, imaging, and interpretation are active focus areas in current industry and academic applications. Unlocking their cumulative potential in single-focus applications can have a transformative impact, possibly leading to dramatic cost reductions in key use cases and new application areas for enhanced actionable business intelligence. We present field study results from Texas and California that show the potential for imaging pipelines and other subsurface infrastructure by using AI-based methods on high-resolution aboveground magnetic data. The superior resolution and interpretability over conventional geophysical inversion is demonstrated. The method has the potential to provide actionable intelligence in several business-use cases for detecting and characterizing pipelines, crossing zones for multiple pipes, etc. at dramatically reduced costs. The advanced algorithms and workflows used resulted in a 100-fold increase in efficiency and delivered results in two days compared to what could take several months using generally available open-source deep learning AI workflows and software. Future direction of development is to validate against excavation-/drill-bit-/inline-tool-based ground truth and further extend and develop this process to deliver near real-time results. The techniques used are general and can be applied to other geophysical data including seismic, electromagnetic, and gravity at various scales and resolution.
The aim of the study was to determine the effect of static magnetic field (SMF) and electromagnetic field (EMF), of values usually recorded near submarine cables, on the bioenergetics, oxidative stress, and neurotoxicity in the cockle Cerastoderma glaucum. Bivalves maintained a positive energy balance, but the filtration rate and energy available for individual production were significantly lower in SMF-exposed animals compared to the control treatment. No changes in the respiration were noted but ammonia excretion rate was significantly lower after exposure to EMF. Changes in the activities of antioxidant enzymes and the lipid peroxidation were not observed however, exposure to both fields resulted in increased protein carbonylation. After exposure to EMF a significant inhibition of acetylcholinesterase activity was observed. As the present study for the first time revealed the oxidative damage and neurotoxicity in marine invertebrate after exposure to artificial magnetic fields, the need for further research is highlighted.
Adaptation and resilience are concepts meant to galvanize thinking around the ways and means of ensuring that cities, while standing their ground, develop a capacity to change for the greater good. Political crises across North Africa, the Middle East and Ukraine illustrate how events remote in physical space have impacts that touch everyone around the world: disrupted supply chains, rising prices, food insecurity and the mass movement of people highlight the importance of bringing complex systems thinking, integrated resource management practice and collective action processes to bear even in discrete contexts such as meeting the challenges of urban water security. The evidence in this collection shows highly uneven outcomes in pursuit of urban water security. The chapter authors argue for deeper commitment from all stakeholders toward improved governance through inclusive, transparent and accountable decision processes and practices; green design leading to the use of appropriate and affordable technology; concentrated focus on nature-based solutions that can be jointly undertaken by all stakeholders in order to not only build sustainably but to also build trust and social capital; fairness in pricing and the use of market forces; and specific, targeted actions framed by complex and integrated systems analysis.
The underlying drivers of variation in the colouration (colour and pattern) of animals can be genetic, non‐genetic, or more likely, a combination of both. Understanding the role of heritable genetic elements, as well as non‐genetic factors such as age, habitat or temperature, in shaping colouration can provide insight into the evolution and function of these traits, as well as the speed of response to changing environments. This project examined the genetic and non‐genetic drivers of continuous variation in colouration in a lizard, the jacky dragon (Amphibolurus muricatus). We leveraged a large captive experiment that manipulated parental and offspring thermal environment to simultaneously estimate the genetic and non‐genetic drivers of variation in colouration. We found that the overall brightness, the elongation of the longitudinal stripes on the dorsum and the contrast between light and dark patches of the pattern were all heritable. Colouration varied according to the age of the hatchling; however, the thermal environment of neither the parents nor offspring contributed significantly to colouration. It appears that developmental plasticity and maternal effects associated with temperature are not important drivers of variation in our measures of colouration. Jacky dragons exhibit high variation in dorsal colour and pattern. We investigated the role of heritable genetic and non‐genetic drivers of this variation in colouration. We found only genetic sources contributed to variation in colouration.
A k $k$‐extended q $q$‐near Skolem sequence of order n $n$, denoted by Nnq(k) ${{\mathscr{N}}}_{n}^{q}(k)$, is a sequence s1,s2,…,s2n−1 ${s}_{1},{s}_{2},\ldots ,{s}_{2n-1}$ where sk=0 ${s}_{k}=0$ and for each integer ℓ∈[1,n]\{q} $\ell \in [1,n]\backslash \{q\}$ there are two indices i $i$, j $j$ such that si=sj=ℓ ${s}_{i}={s}_{j}=\ell $ and ∣i−j∣=ℓ $| i-j| =\ell $. For an Nnq(k) ${{\mathscr{N}}}_{n}^{q}(k)$ to exist it is necessary that q≡k(mod2) $q\equiv k\,(\mathrm{mod}\,2)$ when n≡0,1(mod4) $n\equiv 0,1\,(\mathrm{mod}\,4)$ and q≢k(mod2) $q\not\equiv k\,(\mathrm{mod}\,2)$ when n≡2,3(mod4) $n\equiv 2,3\,(\mathrm{mod}\,4)$, where (n,q,k)≠(3,2,3) $(n,q,k)\ne (3,2,3)$, (4,2,4) $(4,2,4)$. Any triple (n,q,k) $(n,q,k)$ satisfying these conditions is called admissible. In this manuscript, which is Part III of three manuscripts, we construct the remaining sequences; that is, Nnq(k) ${{\mathscr{N}}}_{n}^{q}(k)$ for all admissible (n,q,k) $(n,q,k)$ with q∈⌊n+23⌋,⌊n−22⌋ $q\in \left[\lfloor \frac{n+2}{3}\rfloor ,\lfloor \frac{n-2}{2}\rfloor \right]$ and k∈⌊2n3⌋,n−1 $k\in \left[\lfloor \frac{2n}{3}\rfloor ,n-1\right]$.
BACKGROUND : Pediatric obesity management can be successful, but some families discontinue care prematurely ( i.e., attrition), limiting treatment impact. Attrition is often a consequence of barriers and constraints that limit families’ access to obesity management. Family Navigation (FN) can improve access, satisfaction with care, and treatment outcomes in diverse areas of healthcare. To help our team prepare for a future effectiveness trial, the objectives of our randomized feasibility study are to (i) explore children's and caregivers' acceptability of FN and (ii) examine attrition, measures of study rigour and conduct, and responses to FN + Usual Care vs Usual Care by collecting clinical, health services, and health economic data. METHODS : In our 2.5-year study, 108 6–17-year-olds with obesity and their caregivers will be randomized (1:1) to FN + Usual Care or Usual Care after they enroll in obesity management clinics in Edmonton, Calgary, and Mississauga, Canada. Our Stakeholder Steering Committee and research team will use Experience-Based Co-Design to design and refine our FN intervention to reduce families’ barriers to care, maximizing the intervention dose families receive. FN will be delivered by a navigator at each site who will use logistical and relational strategies to enhance access to care, supplementing obesity management. Usual Care will be offered similarly at each clinic, adhering to expert guidelines. At enrollment, families will complete a multidisciplinary assessment, then meet regularly with a multidisciplinary team of clinicians for obesity management. Over 12 months, both FN and Usual Care will be delivered virtually and/or in-person, pandemic permitting. Data will be collected at 0, 3, 6, and 12 months post-baseline. We will explore child and caregiver perceptions of FN acceptability as well as evaluate attrition, recruitment, enrolment, randomization, and protocol integrity against pre-set success thresholds. Data on clinical, health services, and health economic outcomes will be collected using established protocols. Qualitative data analysis will apply thematic analysis; quantitative data analysis will be descriptive. DISCUSSION : Our trial will assess the feasibility of FN to address attrition in managing pediatric obesity. Study data will inform a future effectiveness trial, which will be designed to test whether FN reduces attrition. TRIAL REGISTRATION : This trial was registered prospectively at clinicaltrials.gov (#NCT05403658; first posted: June 3, 2022); full details available at: https://clinicaltrials.gov/ct2/show/NCT05403658.
Organisms from the Synechococcus genus constitute one of the major contributors to oceanic primary production, broadly distributed in waters with wide range of environmental conditions. This work investigated the influence of abiotic factors (temperature, irradiance, and salinity) on the strength of allelopathic interactions between different phenotypes of picoplanktonic cyanobacteria of the genus Synechococcus sp. (Type 1, Type 2, and Type 3a) employing mixed cultures and cell-free filtrate assays. The response variables studied were population growth and content of photosynthetic pigments: chlorophyll a (Chl a), carotenoids (Car), phycocyanin (PC), phycoerythrin (PE), and allophycocyanin (APC). Temperature was shown to be the most significant abiotic factor impacting the allelopathy of Synechococcus sp. phenotypes, with the Type 2 most significantly impacted. Irradiance also had a significant effect, having the largest effect on allelopathy of Type 3a phenotype. Changes in salinity had the greatest effect on allelopathy of Type 1. Our study has shown the significant influence of temperature, irradiance, and salinity on the strength of allelopathic compounds secreted by Synechococcus sp. phenotypes, with temperature the most significantly affecting allelopathic properties. Moreover, we discovered that the allelopathic response to changing environmental factors is highly phenotype-specific. This differential response of allelopathy could help different phenotypes of Synechococcus sp. to coexist in the water column.
Headwater streams, especially those flowing through forested landscapes, are mainly detritus-based systems. The interactions between leaf litter, microbial decomposers and invertebrate detritivores set the course for the vital carbon flow in these ecosystems. Among the microbial decomposers, fungi, particularly aquatic hyphomycetes (AQHs) are the primary mediators of carbon and nutrient flow across food webs. AQHs channel ≥ 50% of their production in releasing a prodigious number of asexual spores (conidia) directly from the leaf litter into the water. Spores can be used as proxies for Darwinian fitness, ensuring dispersal and representation in the next generation. They are also critical constituents of fine particulate organic matter serving, potentially, as food for filter feeders and collectors, two important functional invertebrate groups. Yet to date, the role of AQH spores in the energy pathway in streams has rarely been explored. Here we discuss what progress has been made in exploring spores as a fundamental aspect of AQH research. We hope to point out potential blind spots in stream ecology and to stimulate research on the functions of spores in forested streams. This chapter articulates unresolved pivotal aspects such as biodiversity and biogeography of spores, environmental cues for their production, germination and viability, and their role as carriers of essential molecules in streams. Addressing these issues should allow ecologists to deepen their knowledge of ecosystem functioning across the globe and help manage vulnerable ecosystems.
Background Genito-pelvic pain (GPP) affects a sizable minority of women and results of existing treatments can be variable. A method of general pain treatment that has not yet been extended to penetration-related GPP is Explicit Motor Imagery (EMI), which uses pain-related images to help individuals with pain alter their responses to pain, resulting in reduced pain, less pain-related anxiety, and improved function. Aim As a first step toward determining if EMI is a feasible method for treating penetration-related GPP, this study examined whether images that potentially signal genital pain are sufficient to induce an anxiety or anticipated pain response in women. Methods Participants were 113 women (62 with genital pain, 51 pain-free) recruited to complete an online study. Participants viewed randomized images of women engaging in various activities that potentially cause pain for people with penetration-related GPP (sitting, walking, running, lifting, inserting a tampon, implied penetrative sex, actual penetrative sex, implied gynecological exam, actual gynecological exam). Participants then rated each image on how much anxiety they experienced viewing the picture (viewing anxiety), and how much anxiety (anticipated anxiety) and pain (anticipated pain) they expected to experience doing the activity in the picture. Outcomes Outcomes were the self-reported viewing anxiety, anticipated anxiety, and anticipated pain of women with and without self-reported penetration-related GPP in response to the pain-related images. Results Women who experienced self-reported penetration-related GPP reported significantly higher levels of viewing anxiety, anticipated anxiety, and anticipated pain in almost all categories of images, compared to women who were free of pain. The key exception was that women with and without self-reported penetration-related GPP reported similar levels of viewing anxiety when looking at images of implied and actual penetrative sex. Clinical Translation These results support that pelvic and genital imagery serve as a sufficient stimulus to generate anxiety and anticipated pain in our study sample. EMI, which targets desensitization of heightened anxiety warrants further research as a potential novel treatment option. Strengths & Limitations This study was the first to assess responses to a wide array of pain-eliciting images in women with and without self-reported penetration-related GPP. A key limitation was that the pain sample was self-reported and not clinically diagnosed. Conclusion Images of pain-related stimuli were sufficient to induce anxiety and anticipated pain in women with self-reported penetration-related GPP. This first step suggests that EMI may be a useful treatment option for women with penetration-related GPP. Kelly KJM, Fisher BL, Rosen NO, et al. Anxiety and Anticipated Pain Levels of Women With Self-Reported Penetration-Related Genito-Pelvic Pain are Elevated in Response to Pain-related Images. J Sex Med 2022;XX:XXX–XXX.
The helicity-dependent single π0 photoproduction cross section on the deuteron and the angular dependence of the double polarisation observable E for the quasi-free single π0 production off the proton and the neutron have been measured, for the first time, from the threshold region up to the photon energy 1.4 GeV. The experiment was performed at the tagged photon facility of the MAMI accelerator and used a circularly polarised photon beam and longitudinally polarised deuteron target. The reaction products were detected using the large acceptance Crystal Ball/TAPS calorimeter, which covered 97% of the full solid angle. Comparing the cross section from the deuteron with the sum of free nucleon cross sections provides a quantitative estimate of the effects of the nuclear medium on pion production. In contrast, comparison of the E helicity asymmetry data from quasi-free protons off deuterium with data from a free proton target indicates that nuclear effects do not significantly affect this observable. As a consequence, it is deduced that the helicity asymmetry E on a free neutron can be reliably extracted from measurements on a deuteron in quasi-free kinematics.
In terrestrial vertebrates, inhalation of airborne engineered nanomaterials (ENMs) can trigger an oxidative stress response, subsequently leading to vascular inflammation and cardiorespiratory dysfunction. Direct or indirect oxidative stress is frequently cited as a mechanism of ENM toxicity in aquatic organisms, and a growing body of evidence suggests suspended ENMs may also trigger cardiorespiratory dysfunction in these animals via similar mechanisms. This chapter will provide an overview of current data on the cardiorespiratory toxicity of ENMs in aquatic animals, with a particular focus on fish as the most thoroughly investigated model system. Potential underlying mechanisms will be outlined, and the physiological and ecological impacts of ENM‐induced cardiorespiratory dysfunction will be discussed.
Background: As more adults reach advanced age with natural teeth, there is an increasing need for dental and dental hygiene practices to provide care for older adults and individuals living with dementia. Little is known about how well these populations are accommodated in private practice. Methods: Following approval from the Research Ethics Board at Mount Allison University, a survey was sent to the 517 practising dental hygienists in New Brunswick, Canada. They were asked to rate on 5-point scales their geriatric oral care knowledge, their willingness to receive more education on the topic, and how frequently they adjusted their care provision to meet the needs of older (age 70+) clients and those living with dementia. Results: A total of 121 dental hygienists responded (23.4% response rate). Overall, respondents were willing to learn more about geriatric care, but lacked knowledge about the oral health effects of certain medications frequently used by older adults, and about techniques for accessing the oral cavity of clients with dementia. Many accommodations recommended by geriatric specialists were not consistently carried out. Discussion: Given that older adults and adults with dementia make up an increasingly large part of the population in need of oral care, geriatric and dementia oral care needs should be emphasized in dental and dental hygiene practices and continuing education for dental hygienists. Conclusion: More research is required on the impact of integrating accommodations for older clients and clients with dementia into clinical practice, as well as how oral care is experienced by these populations.
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942 members
Robert Hawkes
  • Department of Physics
Felix Baerlocher
  • Department of Biology
Amanda M Cockshutt
  • Department of Chemistry and Biochemistry
Nathaniel Johnston
  • Department of Mathematical and Computer Science
Zoe V Finkel
  • Department of Geography and Environment
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Sackville, New Brunswick, Canada