172 research outputs found
UMaine Office for Diversity and Inclusion_ Happy Valentines and Self-Care! Email
Full text linkEmail from the UMaine Office for Diversity and Inclusion with various details of the Office\u27s work, Black History Month events, and featuring a letter from Dr. Sonja K. Birthisel Director of the Wilson Center regarding the Wabanaki peoples of Maine
Multi-Tactic Ecological Weed Management in a Changing Climate
Full text linkClimate change is expected to impact weed communities in Maine, and the efficacy of tools and tactics farmers use to manage them. Through seedbank sampling and surveys of Maine organic farms, we identified currently rare weeds that are known to be especially abundant or problematic in warmer areas of the USA and might therefore represent an emerging agronomic risk. Many ecological weed management strategies that focus on depleting the weed seedbank are expected to remain effective in a changing climate, and become increasingly important as efficacy of cultivation and some herbicide applications diminish or become more variable. Through field experiments, we evaluated the efficacy of one seedbank management strategy, soil solarization (clear plastic) for stale seedbed creation. We found that two weeks of solarization followed by flaming created an effective stale seedbed, reducing subsequent weed density by 78% as compared to a control prepared with flaming only. In response to farmer questions, we measured solarization’s impacts on soil microbiota, and compared its weed control efficacy to that of tarping (black plastic). Soil biological activity was somewhat reduced by solarization, though results are likely temporary. Solarization was more effective than tarping in one site-year, but tarping outperformed solarization in the other. Overall, solarization is a promising weed management strategy for high-value crops, and one that is likely to remain effective in Maine’s changing climate. Maine is home to a growing population of beginning farmers, who face steep learning curves related to weed management. As a first step toward improving beginning farmer education, we constructed a digital tool called WEEDucator designed to engage users in interactive learning related to ecological weed management. Through a structured educational intervention we found that WEEDucator improved knowledge of weed ecology and management among agriculture students, and was ranked as a preferred learning method. Overall, the findings of this dissertation can aid in the development of outreach materials on climate-resilient ecological weed management practices suitable for farmers in Maine
Sources of Variability in Agronomic Weed Seed Predation: Time, Space, Habitat, and Hyperpredation
Full text linkWeed seed predation is an ecosystem service that benefits farmers by decreasing seedbank inputs, thereby reducing weed pressure in subsequent growing seasons. Seed predation can be considerable, but is highly variable. Sources of variability may include time, space, habitat, and trophic interactions such as hyperpredation. Two experiments were conducted to measure the impacts of these sources of variability on weed seed predation rates in Maine mixed vegetable agroecosystems.
Chapter One of this thesis describes a series of landscape-level field experiments conducted to quantify the effects of time, space, and habitat on seed predation rates. Seed assays, with and without vertebrate exclosures, were used to measure seed predation at spatially explicit sample sites across crop and non-crop habitats on a ‘typical’ Maine organic mixed vegetable farm. Total and invertebrate seed predation averaged 8% and 3% day-1, respectively. Motion-sensing wildlife cameras indicated that vertebrate seed predators included small mammals and birds. Pitfall trapping data indicated that one species of carabid, Harpalus rufipes, was highly dominant, comprising 66% of invertebrate seed predators captured within crop fields. Correlogram analysis showed that seed predation was randomly distributed in space. Based on linear mixed effects models, time and habitat were highly significant drivers of seed predation. Total seed predation varied between years of study, and both total and invertebrate seed predation decreased from August to October with winter’s approach. Total seed predation was greater in crop and riparian forest habitats than in mowed grass, meadow, or softwood forest. Generally, invertebrate seed predation was greatest at sites with moderate habitat complexity, while habitat type was the chief biotic determinant of vertebrate seed predation rates. In this study system, time and habitat were more important regulators of seed predation than was space.
Chapter Two describes an experiment conducted to measure hyperpredation of H. rufipes and explore its effects on the weed seedbank. H. rufipes prefer sites with vegetative cover to fallow sites, preference speculated to be driven by predator avoidance behavior. To test this hypothesis, ‘hyperpredation assays’ were developed, in which live H. rufipes prey were presented to higher-order predators. Field trials were conducted to determine foremost if H. rufipes was subject to predation, and secondly, whether a) vegetative cover affords H. rufipes protection from hyperpredators, and b) high hyperpredation rates correspond with decreased invertebrate seed predation rates. Hyperpredation was 2.8% per day. Motion- sensing cameras indicated that H. rufipes’ predators included birds and small mammals. Neither a relationship between hyperpredation and vegetative treatment, nor an empirical relationship between hyperpredation and invertebrate seed predation were found. However, a simulation model predicted that hyperpredation at the rate observed could increase seedbank inputs by more than 17% annually. Additionally, complex habitats supported higher rates of hyperpredation than did simple habitats
Habitat effects on second-order predation of the seed predator Harpalus rufipes and implications for weed seedbank management
No full textExamining the Influence of Racial Microaggression in the Recruitment, Retention, Promotion, Self-Efficacy, and Mental and Physical Health of Black Women Education Administrators in K-12 Public Schools
No full textThe purpose of this study was to examine the influence of racial microaggressions in recruiting, retention, and promotion of Black women educational administrators in K-12 public schools and to understand how racial microaggressions impact mental and physical wellbeing, and self-efficacy. This study included a mixed method approach which consisted of a quantitative online survey and qualitative semistructured interviews from Black women who were current or former administrators. The results from the survey revealed that Black women who are administrators encounter microaggressions, microassaults, and microinvalidations in their place of work which leads to stress. There were six themes that emerged from the semistructured interviews were: we are not favored, we are not represented in leadership roles, we are not valued, I question myself, we are not okay, and we are mentally exhausted. The conclusions suggested that Black women who are in administrative roles in their respective school districts need other Black mentors to buffer the stress that they experience caused by microaggressions. In addition, Black women who are administrators need to be protected from hostile environments that prevent them from being their best selves. Most importantly, Black women who are administrators need to be seen, heard, valued, and appreciated in their workplace. It is recommended that future studies be conducted using the Gendered Racial Microaggression Scale for Black Women who are in management and leadership positions in their respective school districts
Samþætting aðferða við læsiskennslu : byrjendalæsi, K-Pals, Pals og Leikur að læra
No full textÍ þessari ritgerð er sagt frá starfendarannsókn á reynslu eins kennara af samþættingu fjögurra kennsluaðferða við læsiskennslu á yngsta stigi grunnskóla. Aðferðirnar eru: Byrjendalæsi, K-pals, Pals og Leikur að læra. Rannsóknin var gerð í fámennum skóla, þar sem kennarinn sem jafnframt var rannsakandi, starfar sem umsjónarkennari í 1.-2. bekk en þeim árgöngum er kennt saman. Markmið rannsóknarinnar var að meta hvort og þá hvernig samþætting þessara aðferða gæti auðgað læsisnám nemenda.
Leitað var eftir mati nemenda, mati aðstandenda og auk þess fylgdist stuðningsfulltrúi með starfi kennarans og nemenda í völdum kennslustundum og skráði hjá sér athugasemdir. Gagna var aflað með dagbókarskrifum, viðtölum og viðhorfakönnunum, vettvangsathugunum og mati á afrakstri vinnu nemenda.
Meginniðurstöður rannsóknarinnar sýna að nemendur sýndu námsefninu áhuga og voru virkir og viljugir til að læra nýtt efni. Einnig sýna niðurstöður að aðstandendur voru ánægðir með kennsluna, þeim fannst nemendur sýna náminu áhuga og vera ánægðir í skólanum.
Niðurstöður benda til að samþætting aðferðanna hafi tekist og að kennarinn hafi fengið staðfestingu á réttmæti þess að nota fleiri en eina kennsluaðferð til að styrkja læsisnám nemenda.This dissertation reports a practioner research into the experience of one classroom teacher of the integration of four different methods of teaching literacy to young elementary students. These methods are Beginning Literacy, K–pals, Pals and Play to learn more. The research took place in a small school where the teacher, who is also the researcher, works as a class teacher in grades 1 and 2 where those grades are tought together as one multi-age group. The aim of the research was to evaluate if and how integrating these methods would enrich the literacy learning of the students.
Data was collected from students and parents and a classroom assistant also observed the teachers and students working in selected lessons and took notes. The data included journals, interviews, a questionnaire survey, field notes from observations, and evaluation of students work.
The main results of the research is that the students were intresed in their activities, they were engaged and willing to learn something new. The results also indicate that parents were satisfied with the teaching, they felt the students were interested in learning and happy in school.
The author concludes that the integration of the methods was successful and confirmed the value of using multiple methods to enrich the literacy education of students.Ritgerðin sem og fylgiskjöl eru opin og öllum aðgengileg. Hins vegar ef óskað er eftir frekari upplýsingum um verkefni eða fá aðgang að verkefnum er hægt að hafa samband við mig í gegnum netfangið [email protected]
A Note on Case-Based Optimization with a Non-Degenerate Similarity Function
Full text linkThe paper applies the ��realistic-ambitious�� rule for adaptation of the aspiration level suggested by Gilboa and Schmeidler (1996) to a situation in which the similarity between the available acts is represented by a non-degenerate function. The paper shows that the optimality result obtained by Gilboa and Schmeidler (1996) in general fails. With a concave similarity function, the best corner act is chosen in the limit. Introducing convex regions into the similarity function improves the limit choice. A sufficiently fine similarity function allows to approximate optimal behavior with an arbitrary degree of precision.
High-resolution extreme ultraviolet spectroscopy of G191-B2B: structure of the stellar photosphere and the surrounding interstellar medium
No full textWe have continued our detailed analysis of the high-resolution (R= 4000) spectroscopic observation of the DA white dwarf G191-B2B, obtained by the Joint Astrophysical Plasmadynamic Experiment (J-PEX) normal incidence sounding rocket-borne telescope, comparing the observed data with theoretical predictions for both homogeneous and stratified atmosphere structures. We find that the former models give the best agreement over the narrow waveband covered by J-PEX, in conflict with what is expected from previous studies of the lower resolution but broader wavelength coverage Extreme Ultraviolet Explorer spectra. We discuss the possible limitations of the atomic data and our understanding of the stellar atmospheres that might give rise to this inconsistency. In our earlier study, we obtained an unusually high ionization fraction for the ionized He ii present along the line of sight to the star. In the present paper, we obtain a better fit when we assume, as suggested by Space Telescope Imaging Spectrograph results, that this He ii resides in two separate components. When one of these is assigned to the local interstellar cloud, the implied He ionization fraction is consistent with measurements along other lines of sight. However, the resolving power and signal-to-noise available from the instrument configuration used in this first successful J-PEX flight are not sufficient to clearly identify and prove the existence of the two components
Methodus: An Autograph of Josip Herović Dating Back to 1797
Full text linkVrijedan povijesni izvor za povijest školstva u 18. i početkom 19. stoljeća u Hrvatskoj autograf je Josipa Herovića iz 1797. “Methodus”. Riječ je o prijevodu (ili prijepisu prijevoda) učiteljskoga priručnika “Kern des Methodenbuches, besonders für die Landschulmeister in den k. k. Staaten” na hrvatski kajkavski jezik. Od 1901. rukopis se čuva u Arhivskoj zbirci Hrvatskoga školskog muzeja. U hrvatskoj historiografiji poznati su djelomični sadržaj i značenje “Methodusa”, a njegov cjeloviti tekst prvi se put objavljuje kao povijesna građa. U radu se daje kontekst nastanka, opis i sažeti prikaz sadržaja autografa te pregled pedagoškoga djelovanja njegova autora, samoborskoga učitelja Josipa Herovića (1780. – 1871.).The 1797 autograph of Josip Herović titled “Methodus” is a valuable historical source of information about the history of schooling in the 18th and early 19th centuries. It is a translation (or rather a transcript of a translation) of the teacher manual “Kern des Methodenbuches, besonders für die Landschulmeister in den k. k. Staaten” into the Croatian kajkavian language. The manuscript has been kept in the Archival Collection of the Croatian School Museum. Some of the content and meaning of “Methodus” is partly known in Croatian historiography and its integral text was first published as historical material. The paper provides the context of the creation, a description and a summary of the autograph, as well as an overview of the teaching activities undertaken by its author Josip Herović, a teacher in Samobor (1780–1871)
Development and validation of main spectral profile for rapid identification of Yersinia ruckeri isolated from Atlantic salmon using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
No full textMatrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows rapid and reliable identification of microorganisms. The accuracy of bacterial identification using MALDI-TOF MS depends on main spectral profiles (MSPs) provided in a quality-assured commercial reference library, which requires ongoing improvement. This study aimed to develop and validate an in-house MALDI-TOF MS MSP to rapidly identify Yersinia ruckeri isolated from Atlantic salmon (Salmo salar). The novel MSP was prepared using an isolate of Y. ruckeri recovered from Atlantic salmon and confirmed by 16S rRNA gene sequencing. Subsequently, a validation set which comprises 29 isolates of Y. ruckeri were examined from three fishes: Atlantic salmon (Salmo salar) (n = 26), American eel (Anguilla rostrata) (n = 1), and Atlantic cod (Gadus morhua) (n = 2). These isolates were randomly selected from the Atlantic Veterinary College, Aquatic Diagnostic Services Bacteriology Laboratory's culture collection to validate the novel MSP. Analytical sensitivity of MALDI-TOF MS using the novel MSP to identify the validation set was 86.2%. Repeatability was assessed by acquiring spectra from 30 different spots of a randomly-selected isolate of Y. ruckeri, and analyzed spectra from each spot were compared against the novel MSP. The coefficient of variation was 3.3%. The novel MSP clustered with Bruker MSPs (n = 3) of Y. ruckeri in the reference library and did not falsely identify any closely related bacteria to Y. ruckeri. This study reports the development of a novel MSP of high analytical sensitivity and specificity for rapid identification of Y. ruckeri using MALDI-TOF MS
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