Development and implementation of a watershed-scale cumulative effects framework for the Athabasca River Basin

Over the recent decades, there has been an increase in human-related negative environmental impacts on aquatic ecosystems worldwide. These impacts are varied and can include climatic variations as well as increased urban and industrial developments. These impacts can be challenging to manage as they can manifest themselves in a cumulative manner over very large spatial (watershed) and temporal (decadal) scales. In response to these challenges, scientists have been developing methods which attempt to assess the increasingly complex interactions between our environment and the current and future demands of society. This thesis proposes a framework for quantifying cumulative changes in water quality and quantity and demonstrates its implementation in an entire watershed, the Athabasca River basin in Alberta, Canada. The Athabasca River basin is an ideal watershed for this study as it has undergone significant increases in urban and industrial developments which have the potential to impact this aquatic ecosystem. The province of Alberta, Canada is currently experiencing significant economic growth as well as increasing public awareness of its dependence on water. The Athabasca River is a glacial fed river system with a basin covering 157 000 km2 and is the longest (1538 km) unregulated river in Canada. The basin holds significant cultural and economic importance, supporting more than nine First Nation groups, and providing water to hundreds of industries. There has been an increasing level of industrial, urban and other land-use related development (pulp and paper mills, oil sands developments, agriculture, and urban development) within the Athabasca River basin. Many of the historical water quantity and quality data for this basin have not been integrated or analyzed from headwaters to mouth, which affects development of a holistic, watershed-scale cumulative effects assessment. The main goal of this thesis was to develop and apply a quantitative approach (framework) to assess and characterize the cumulative effects of man-made stressors (e.g. municipal effluent, pulp and paper effluents, oil sands) on indicators of aquatic health (water quality and biological responses) over space and time for a model Canadian river, the Athabasca River, Alberta. This framework addresses the problems of setting an historical baseline, and comparing it to the current state in a quantitative way. This framework also creates the potential for the prediction of future impacts by creating thresholds specific to the study area. The outcome of this framework is the identification and quantification of specific stressors (dissolved sodium, chloride and sulphate) showing significant change across the entire Athabasca River basin, as well as the development of thresholds for these parameters. The first part of this framework was to quantify any spatial and temporal changes in water quality and quantity across the entire basin from headwaters to mouth, across two time periods, historical and current, over a period of 40 years. Data were collected from several federal, provincial and non-government sources. A 14-30% decrease in discharge was observed during the low flow period in the current time period in the lower three river reaches with the greatest decrease occurring at the mouth of the river. Dissolved sodium, sulphate and chloride concentrations in the second time period were greater than, and in some cases double, the 90th percentiles calculated from the first time period in the lower part of the river. Based on these findings, the second portion of the framework involved developing basin-specific thresholds for these parameters using the partial life-cycle fathead minnow (Pimephales promelas) bioassay. Two laboratory experiments (dissolved sodium and dissolved chloride) and three field experiments (sodium chloride, dissolved sulphate and water collected downstream of industrial inputs at the mouth of the Athabasca River) were conducted using a diluter system allowing for the dilution of a 100% test solution (based on the highest recorded concentration of the respective parameter in the river) down to 50%, 25%, 12.5%, 6.25% and a 0% control. Significant changes in egg production were identified and linked to changes in gill diffusion distances illustrating the chronic impacts of these parameters on fathead minnow (FHM). The threshold range determined in the laboratory for dissolved sodium was between 12.5% (36.11 mg/L) and 50% (57.00 mg/L) and dissolved chloride less than 22.22 mg/L. At levels outside or above these ranges a possible decrease in reproductive output may occur. The threshold range determined in the field studies for dissolved sulphate concentration was between 23.33 mg/L and 100 mg/L and for the sodium chloride experiment the greatest increases in reproductive output occurred in the highest treatment (25.43 mg/L Na and 38.90 mg/L Cl) which was similar to the range identified in the laboratory study for dissolved sodium. These results showed that significant changes have occurred in both water quantity and quality between the historical and current day Athabasca River basin. It is known that in addition to climatic changes, rivers which undergo increased agricultural, urban and industrial development can experience significant changes in water quantity and quality due to increased water use, discharge of effluents and surface run-off. Using the results from this thesis, we can begin to quantify dominant natural and man-made stressors affecting the Athabasca River basin as well as place the magnitude of any local changes into an appropriate context relative to trends in temporal and spatial variability. This thesis is a significant contribution to method development for watershed-scale cumulative effects assessment including development of whole river benchmarks for sublethal exposures of fish to increasing salinity for a river of economic and cultural importance and experiencing significant development pressure

Engineering solid-state nanopores for detection of single transcription factors bound to DNA

Thesis (Ph.D.)--Boston UniversityDetection and characterization of nucleic acid-protein interactions, particularly those involving DNA and transcription factors, remain significant barriers to our understanding of genetic regulation. Solid-state nanopores are extremely sensitive single molecule sensors with the capability to map local chemical and structural characteristics along the length of a biopolymer, providing label-free detection for a wide range of analyte lengths and sizes. Previous studies have utilized solid-state nanopores to detect complexes of DNA bound to many large proteins, but improvements to the sensing resolution of the nanopore platform are necessary for detection of single small transcription factors bound to DNA. This project encompasses two novel nanopore modifications that enhance output signal quality and time resolution in nanopores, and establishes solid-state nanopores as a platform for direct measurement of transcription factor-DNA complexes. First, a novel fabrication process was developed to create locally thinned SiN membranes on a full-wafer scale. These modified nanopore chips provide several advantages over conventional solid-state nanopores, including improved signal-to-background ratio, higher probability of functionality, and clearly marked pore locations for re-imaging and array fabrication. Next, the volume outside the nanopore was modified by electrospinning a sparse, hydrophobic co-polymer nanofiber mesh (NFM) directly onto the nanopore chip. The NFM interacts with analyte molecules as they translocate through the pore, increasing residence time in the sensing volume and improving resolution by more than two orders ofmagnitude for a chemically optimized blend ofpoly(E-caprolactone) and poly(glycerol-co-E-caprolactone). Finally, modified nanopores were used for direct, label-free detection of single transcription factors bound to DNA. Translocations of these complexes reveal a combination oftwo possible sensing modalities; either the complex passes unhindered through the pore, causing a transient drop in current at the location ofthe bound protein, or the protein is unable to translocate and is removed as the DNA is electrophoretically driven through the nanopore. The DNA-binding domain of the transcription factor Early Growth Response Protein 1 (EGRl), known as zif268, is presented as a model system for this research. EGRl activates genes that control cell differentiation and mitogenesis, and participates in many regulatory processes including wound response, tumor suppression, and neuronal plasticity

Interferometric scattering enables fluorescence-free electrokinetic trapping of single nanoparticles in free solution

Anti-Brownian traps confine single particles in free solution by closed-loop feedback forces that directly counteract Brownian motion. The extended-duration measurement of trapped objects allows detailed characterization of photophysical and transport properties, as well as observation of infrequent or rare dynamics. However, this approach has been generally limited to particles that can be tracked by fluorescent emission. Here we present the Interferometric Scattering Anti-Brownian ELectrokinetic trap (ISABEL trap), which uses interferometric scattering rather than fluorescence to monitor particle position. By decoupling the ability to track (and therefore trap) a particle from collection of its spectroscopic data, the ISABEL trap enables confinement and extended study of single particles that do not fluoresce, that only weakly fluoresce, or which exhibit intermittent fluorescence or photobleaching. This new technique significantly expands the range of nanoscale objects that may be investigated at the single-particle level in free solution.Comment: Manuscript and SI; videos available upon reques

Seasonal Resource Allocation and Accumulated Degree Day Estimation for Cuban Bulrush (Oxycarum cubense) in the Southeastern U.S.

Cuban bulrush (Oxycaryum cubense (Poepp. & Kunth) Lye) is a non-native aquatic plant from South America and the West Indies, first introduced into the United States in 1878. This study focused on the resource allocation and accumulated degree day modeling of the monocephalous and polycephalous Cuban bulrush populations in Mississippi, Louisiana, and Florida. Environmental factors such as photoperiod and temperature were analyzed on its effect on plant growth. From October 2021- September 2022 Cuban bulrush biomass was harvested monthly from two 0.04 Ha (0.1 ac) plots in each state. Height was measured during each monthly event. Environmental monitoring of photoperiod and air temperature were also measured monthly. Starch analyses were completed using the amylase/amyloglucosidase method via a commercially available STA-20 starch assay kit. Linear and polynomial regressions were conducted between Cuban bulrush biomass, starch content, and environmental variables. A Kruskal-Wallis One-Way ANOVA was conducted on total, inflorescence, emergent, and submersed biomass and starch to determine if each state had an effect. Accumulated degree day modeling was done using the Single Sine method by Snyder et al. (1999). Almost all Mississippi biomass and starch had negative relationships with photoperiod and air temperature. All biomass had a significant state effect (P\u3c0.01), while total and emergent starch had a significant effect between Mississippi and Florida (P\u3c0.01). Starch content was not prominent in any one tissue (\u3c1.4% DW). Phenological differences were identified between the monocephalous and polycephalous biotype where the monocephalous had more allocation to total biomass, while the polycephalous focused more on inflorescence. Monocephalous inflorescence peaked in the summer, while polycephalous peaked in the winter. Model results show base threshold temperatures below 0°C, and the potential of Cuban bulrush to expand north. Future recommendations include future growth studies based on modeling data from this study

Sembrando una profesión: la intersección entre el Estado, los intereses internacionales y el desarrollo precoz de la enfermería brasileña

State and international entities can have profound effects on the development of a country’s nursing profession. Through a global health governance lens, this paper explores the development of nursing in Brazil during the early twentieth century, and its intersections with national and international interests. Accordingly, we will show how state policies established an environment that fostered the institutionalization of nursing as a profession in Brazil and supported it as a means to increase the presence of females in nation building processes. The State focused on recruiting elite women for nursing, in part due to the Rockefeller Foundation’s involvement in the country. Nurses who worked for Rockefeller came from well-educated classes within US society with specific ideas about who should be a nurse and the roles of nurses in a healthcare system. These women served as the primary vehicles for interacting with Brazilian health authorities responsible for health system development. Their early efforts did not, however, ensure a system capable of producing nursing human resources at a rate that, in present day Brazil, could meet the health needs of the country. Findings from this paper offer new avenues for historians to explore the early roots of professional nursing through a global health governance lens, improve the understanding of the intersection between international politics and professionalization, and highlight how these factors may impact nursing human resources production in the long term.Entidades estatais e internacionais podem ter efeitos profundos sobre o desenvolvimento da profissão de enfermagem de um país. Através de uma lente global de governança de saúde, este documento analisa o desenvolvimento da enfermagem no Brasil durante o início do século XX, e suas interseções com os interesses nacionais e internacionais. Desta forma, vamos mostrar como políticas de Estado estabeleceram um ambiente que promoveu a institucionalização da enfermagem como profissão no Brasil, apoiando-se na ideia de aumentar a presença das mulheres nos processos de construção da nação. O Estado focou em recrutar mulheres de elite para a enfermagem, em parte devido ao envolvimento da Fundação Rockefeller no país. As enfermeiras que trabalharam para a Fundação Rockefeller, provenientes de uma classe social americana bem-educada, tinham ideias específicas sobre quem deveria ser enfermeira e os papéis das mesmas em um sistema de saúde. Estas mulheres atuaram como os principais veículos para a interação com as autoridades brasileiras, responsáveis pelo desenvolvimento do sistema de saúde. Seus esforços iniciais não conseguiram, no entanto, assegurar um sistema capaz de producir recursos humanos de enfermagem a uma taxa que, nos dias de hoje, poderia satisfazer as necessidades de saúde do Brasil. Os resultados do presente estudo oferecem pistas sobre novos caminhos para historiadores explorarem as raízes da enfermagem profissional, utilizando uma perspectiva global de governança de saúde, a fim de melhorar a compreensão da interseção entre políticas internacionais e profissionalização, destacando como esses fatores podem impactar a produção de recursos humanos de enfermagem a longo prazo.Organizaciones estatales e internacionales pueden tener efectos profundos sobre el desarrollo de la profesión de enfermería de un país. A través de la óptica de la gobernación global de la salud, este documento analiza el desarrollo de la enfermería en Brasil en el inicio del siglo XX, y sus intersecciones con los intereses nacionales e internacionales. Por consecuencia, vamos enseñar como las políticas del Estado establecieron un ambiente que promocionó la institucionalización de la enfermería como profesión en Brasil, y la apoyó como medio para aumentar la presencia de las mujeres en los procesos de construcción de la nación. El Estado ha focalizado en el reclutamiento de mujeres de élite para la enfermería, en parte debido al envolvimiento de la Fundación Rockefeller en el país. Enfermeras que trabajaban para Rockefeller, también provenían de clases bien-educadas de la sociedad de los Estados Unidos, imbuidas de ideas específicas sobre quién debería ser una enfermera y su papel en un sistema de salud. Esas mujeres actuaron como vehículos primordiales en la interacción con autoridades brasileñas, responsables por el desarrollo del sistema de salud. Entretanto, sus esfuerzos iniciales no fueron suficientes para garantizar un sistema capaz de producir recursos humanos de enfermería con una tasa que, en los días de hoy, el Brasil podría satisfacer las necesidades de salud del país. Los hallados de este estudio ofrecen pistas sobre nuevos caminos para historiadores explotaren las primeras raíces de la enfermería profesional valiéndose de la lente de gobernanza global de la salud; mejoraren la comprensión de la intersección entre políticas internacionales y profesionalización; y aún destacaren, como eses factores pueden impactar la producción de recursos humanos de enfermería a largo plazo

Methodological considerations when translating "burnout"

No study has systematically examined how researchers address cross-cultural adaptation of burnout. We conducted an integrative review to examine how researchers had adapted the instruments to the different contexts. We reviewed the Content Validity Indexing scores for the Maslach Burnout Inventory-Human Services Survey from the 12-country comparative nursing workforce study, RN4CAST. In the integrative review, multiple issues related to translation were found in existing studies. In the cross-cultural instrument analysis, 7 out of 22 items on the instrument received an extremely low kappa score. Investigators may need to employ more rigorous cross-cultural adaptation methods when attempting to measure burnout

Single-molecule fluorescence multiplexing by multi-parameter spectroscopic detection of nanostructured FRET labels

Multiplexed, real-time fluorescence detection at the single-molecule level is highly desirable to reveal the stoichiometry, dynamics, and interactions of individual molecular species within complex systems. However, traditionally fluorescence sensing is limited to 3-4 concurrently detected labels, due to low signal-to-noise, high spectral overlap between labels, and the need to avoid dissimilar dye chemistries. We have engineered a palette of several dozen fluorescent labels, called FRETfluors, for spectroscopic multiplexing at the single-molecule level. Each FRETfluor is a compact nanostructure formed from the same three chemical building blocks (DNA, Cy3, and Cy5). The composition and dye-dye geometries create a characteristic F\"orster Resonance Energy Transfer (FRET) efficiency for each construct. In addition, we varied the local DNA sequence and attachment chemistry to alter the Cy3 and Cy5 emission properties and thereby shift the emission signatures of an entire series of FRET constructs to new sectors of the multi-parameter detection space. Unique spectroscopic emission of each FRETfluor is therefore conferred by a combination of FRET and this site-specific tuning of individual fluorophore photophysics. We show single-molecule identification of a set of 27 FRETfluors in a sample mixture using a subset of constructs statistically selected to minimize classification errors, measured using an Anti-Brownian ELectrokinetic (ABEL) trap which provides precise multi-parameter spectroscopic measurements. The ABEL trap also enables discrimination between FRETfluors attached to a target (here: mRNA) and unbound FRETfluors, eliminating the need for washes or removal of excess label by purification. We show single-molecule identification of a set of 27 FRETfluors in a sample mixture using a subset of constructs selected to minimize classification errors.Comment: 43 pages, 6 figures, 13 Supplementary figures, 3 Supplementary tables, 5 Supplementary note