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Establishment of a multicomponent dietary bioactive human equivalent dose to delete damaged Lgr5 stem cells using a mouse colon tumor initiation model
No full textMulti-component therapy has gained interest for its potential to synergize and subsequently lower the effective dose of each constituent required to reduce colon cancer risk. We have previously demonstrated that rapidly cycling Lgr5 stem cells are exquisitely sensitive to extrinsic dietary factors that modulate colon cancer risk. In the present study, we quantified the dose-dependent synergistic properties of dietary n-3 polyunsaturated fatty acids (PUFA) and curcumin (Cur) to promote targeted apoptotic deletion of damaged colonic Lgr5+ stem cells. For this purpose, both heterogeneous bulk colonocytes and Lgr5 stem cells were isolated from Lgr5-EGFP-IRES-CreER knock-in mice injected with azoxymethane (AOM). Isolated cells were analyzed for DNA damage (H2AX), apoptosis (cleaved caspase-3) and targeted apoptosis (both γH2AX and cleaved caspase-3) at 12 hr post AOM injection. Comparison of the percentage of targeted apoptosis in Lgr5 stem cells (GFP) across a broad bioactive dose range revealed an ED50 of 16.0 mg/d n-3 PUFA + 15.9 mg/d Cur. This corresponded to a human equivalent dose (HED) of 3.0 g n-3 PUFA + 3.0 g Cur. In summary, our results provide evidence that a low dose (n-3 PUFA + Cur) combination diet reduces AOM-induced DNA damage in Lgr5 stem cells and enhances targeted apoptosis of DNA damaged cells, implying that a lower HED can be utilized in future human clinical trials
Complete Genome Sequence of Vibrio campbellii DS40M4
No full textWe present the complete genome sequence of Vibrio campbellii DS40M4, assembled from Illumina and Oxford Nanopore data. This effort improves upon a previous draft assembly to resolve this organism’s two-chromosome and one-plasmid genetic structure and to provide valuable context for evaluating the gene arrangement and evolution of this species
Galactic Winds in Low-mass Galaxies
No full textStellar-feedback driven outflows are predicted to play a fundamental role in the baryon cycle of low-mass galaxies. However, observational constraints of winds in nearby dwarf galaxies are limited as outflows are transient, intrinsically low-surface brightness features, and, thus, difficult to detect. Using deep Hapha observations, we search for winds in a sample of twelve nearby dwarfs (M_* ~ 10 - 10 M) which host on-going or recent starbursts. We detect features which we classify as winds in 6 galaxies, fountain candidates in 5 galaxies, and diffuse ISM in 1 system. Winds are found preferentially in galaxies with centrally concentrated star formation, while fountains are found in galaxies with spatially distributed star formation. We suggest that the concentration of star formation is a predictor for whether a low-mass galaxy will develop a wind. The spatial extent of all detected ionized gas is limited (<1/10 virial radius) and would still be considered the ISM by cosmological simulations. Our observations suggest that the majority of material expelled from dwarfs does not escape to the intergalactic medium but remains in the halo and may be recycled to the galaxies. Derived mass-loading factors range from 0.2-7 (with only a weak dependency on circular velocity or stellar mass), in tension with higher values in simulations needed to reproduce realistic low-mass galaxies and resolve discrepancies with LambdaCDM. The sample is part of the panchromatic STARBurst IRegular Dwarf Survey - STARBIRDS - designed to characterize the starburst phenomenon in dwarf galaxies. We also report a previously uncatalogued nearby galaxy (J1118+7913)
Elastic Graphs
No full textAn elastic graph is a graph with an elasticity associated to each edge. It may be viewed as a network made out of ideal rubber bands. If the rubber bands are stretched on a target space there is an elastic energy. We characterize when a homotopy class of maps from one elastic graph to another is loosening, i.e., decreases this elastic energy for all possible targets. This fits into a more general framework of energies for maps between graphs
Haiti, Singing for the Land, Sea, and Sky: Cultivating Ecological Metaphysics and Environmental Awareness through Music
Get PDFVodou drummer Jean-Michel Yamba echoes a refrain that has been reverberating through Haitian society for some time: the Earth is dangerously out of balance, and the world’s people are the cause. Scientific studies support this uneasy realization: the 2018 Global Climate Risk Index ranks Haiti as the single most vulnerable country to the effects of extreme weather events related to climate change. This article reflects on how humanity’s responsibility toward the environment has been deeply encoded as traditional ecological knowledge (TEK) within Vodou spiritual ecology, which is expressed through songs and interactions with the lwa (spirits)
Influence of Floods, Tides, and Vegetation on Sediment Retention in Wax Lake Delta, Louisiana, USA
Get PDFSediment is the most valuable natural resource for deltaic environments because it is required to build new land. For land building to occur, sediment must be retained in the delta instead of being transported offshore. Despite this, we do not know what controls sediment retention within a delta. Here we use a calibrated numerical model of Wax Lake Delta, Louisiana, USA to analyze sediment retention for different riverine flood magnitudes, tidal amplitudes, and vegetation extents. Our results show that as riverine flood magnitude increases, areally averaged vertical accretion increases from 0.33 to 2 cm per 60‐day flood, but sediment retention decreases from 72% to 34%. For the uniform vegetation characteristics considered, the buffering effect, defined as the reduction of sediment flux onto the islands in the presence of vegetation, reduces the sediment flux onto the islands 14 to 22% on a fully vegetated delta. When sediment is transported onto the islands, vegetation enhances retention, which we refer to as the trapping effect, by ~10%. But, this does not offset the buffering effect, and vegetation decreases vertical accretion and retention in the delta up to 6% (or ~0.5 cm per 60‐day flood). We suggest that vegetation will increase sedimentation only when trapping compensates for buffering. Finally, greater tidal amplitude at higher discharges enhances vertical accretion by ~0.5 cm per 60‐day flood compared to smaller tidal amplitudes. These results provide insight on the mechanisms behind coastal systems growth, and suggest how sediment diversions might be operated more efficiently in deltas with reduced sediment supply
Cognitive and Affective Scarcities and Relational Abundance: Lessons from the Confluence of Extreme and Chronic Scarcities in Subsistence Marketplaces
Get PDFResearch on subsistence marketplaces provides a number of insights about extreme and chronic resource scarcity as well as intangible scarcities in cognitive and affective realms. These insights have been developed from a variety of sources—quantitative and qualitative research, as well as education for communities and for students through a symbiotic academic-social enterprise. These insights are juxtaposed with extant work on scarcity in consumer research, to derive implications for future research and stimulate thinking on a broad variety of scarcities. Our holistic deep dive into extreme scarcity and its multiple dimensions from the perspective of consumer behavior has much to offer in stimulating future research on scarcity
Instructional Practices for Addressing Computer Science Standards: Using Computer Kits in Preservice Teacher Education
Get PDFThis article examines the instructional practices used to teach the computer science (CS) standard of computer devices and systems to undergraduate preservice teachers (PSTs). With computer science education (CSE) gaining an international focus, there is a need to explore a variety of instructional practices used to teach these topics. This descriptive, exploratory case study presents an examination of the instructional practices used in a CSE licensure course. In this study, the instructor utilised two commercially available computer kits to provide hands-on, learner-centred learning experiences for PSTs. PSTs perceived these kits to be valuable for learning about computing devices and systems topics and for teaching these topics in their future classrooms. Additionally, results showed that PSTs considered the usability, grade level and ability of the kits to build interest in CS when reflecting on their future use. Limitations to the instructional practices included a lack of transfer to subject areas outside of CS and a lack of focus on the integration between hardware and software
Teacher Reading as Professional Development: Insights from a National Survey
Get PDFOver the past four decades, a number of researchers have attempted to describe the reading habits of teachers. Some have investigated the impact of reading habits generally, while most have focused on some kind of loosely defined "professional reading." In relationship to this body of literature, the purpose of our descriptive survey study, which invited teachers from randomly selected schools in both large and small districts across the United States, was to both add to and update the available literature regarding teachers' professional reading habits. We found that reading for professional development appears to be a common activity for the classroom teachers who participated in our survey. We also found that that the bulk of the teachers' professional reading time was completed in the evenings and on weekends. We did not find statistically significant differences in reading preferences and behaviors when differences in degree were considered. Further, we did not find statistically significant differences in reading preferences when we compared the teachers' responses by years of experience. Teachers noted that limited time and lack of relevancy were two primary reasons for why they did not read. We discuss implications for professional development
Articulatory-acoustic relations in the production of alveolar and palatal lateral sounds in Brazilian Portuguese
Get PDFLateral approximant speech sounds are notoriously difficult to measure and describe due to their complex articulation and acoustics. This has prevented researchers from reaching a unifying description of the articulatory and acoustic characteristics of laterals. This paper examines articulatory and acoustic properties of Brazilian Portuguese alveolar and palatal lateral approximants (/l/ and /ʎ/) produced by six native speakers. The methodology for obtaining vocal tract area functions was based on three-dimensional/four-dimensional (3D/4D) ultrasound recordings and 3D digitized palatal impressions with simultaneously recorded audio signals. Area functions were used to calculate transfer function spectra, and predicted formant and anti-resonance frequencies were compared with the acoustic recordings. Mean absolute error in formant frequency prediction was 4% with a Pearson correlation of r = 0.987. Findings suggest anti-resonances from the interdental channels are less important than a prominent anti-resonance from the supralingual cavity but can become important in asymmetrical articulations. The use of 3D/4D ultrasound to study articulatory-acoustic relations is promising, but significant limitations remain and future work is needed to make better use of 3D/4D ultrasound data, e.g., by combining it with magnetic resonance imaging