160 research outputs found

    On Teaching Palindromes

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    Webster\u27s Third New International Dictionary defines palindrome as a word, verse, or sentence that reads the same backward as forward . As is often the case with limericks, sonnets, and other highly-structured but nowadays seldom-pursued literary creations, the few frequently-anthologized examples have come to be the only examples we know. This is certainly the case with the palindrome

    Seed production of barnyardgrass (Echinochloa crus-galli) in response to time of emergence in cotton and rice

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    The spread of herbicide resistance in barnyardgrass (Echinochloa crus-galli (L.) Beauv.) poses a serious threat to crop production in the southern United States. A thorough knowledge of the biology of barnyardgrass is fundamental for designing effective resistance-management programmes. In the present study, seed production of barnyardgrass in response to time of emergence was investigated in cotton and rice, respectively, in Fayetteville and Rohwer, Arkansas, over a 2-year period (2008–09). Barnyardgrass seed production was greater when seedlings emerged with the crop, but some seed production was observed even if seedlings emerged several weeks after crop emergence. Moreover, barnyardgrass seed production was highly variable across environments. When emerging with the crop (0 weeks after crop emergence (WAE)), barnyardgrass produced c. 35 500 and 16 500 seeds/plant in cotton, and c. 39 000 and 2900 seeds/plant in rice, in 2008 and 2009, respectively. Seed production was observed when seedlings emerged up to 5 WAE (2008) or 7 WAE (2009) in cotton and up to 5 WAE (2008, 2009) in rice; corresponding seed production was c. 2500 and 1500 seeds/plant in cotton, and c. 14 700 and 110 seeds/plant in rice, in 2008 and 2009, respectively. The results suggest that cultural approaches that delay the emergence of barnyardgrass or approaches that make the associated crop more competitive will be useful in integrated management programmes. In the context of herbicide resistance management, it may be valuable to prevent seed return to the seedbank, irrespective of cohorts. The findings are vital for parameterizing herbicide resistance simulation models for barnyardgrass

    The Great Debate Between John W. Ring and J. W. Chism

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    https://digitalcommons.acu.edu/crs_books/1094/thumbnail.jp

    Using Cover Crops to Suppress Weeds and Improve Soil Health

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    Herbicide-resistant weeds are creating challenges for producers to control weeds in crop fields. This study explores the potential of cover crops to reduce weed pressure and im­prove soil health. Cover crops were planted after corn harvest in tilled and no-till fields, and included Graza radish, winter wheat, annual ryegrass, spring oats, winter oats, and forage collards. The control was fallow with herbicide application but no cover crop. Soil health was determined prior to cover crop termination. Graza radish and forage collards did not grow consistently in all plots due to poor germination and winter kill. Significant weed biomass was produced in the fallow plot or in plots with poor cover crop stands. Microbial biomass was much greater in the no-till field than in the tilled fields

    Using Cover Crops as an Effective Weed Control Method in Southeast Kansas

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    Weed control is important to optimize crop production. This study was conducted to compare the effectiveness of different methods of fall-implemented weed control strategies. These strategies included different cover crop mixes, chemical control, and mechanical control. The cover crop mixes included four different commonly-planted winter cover crops. The chemical control was a fall-applied burndown, and the me­chanical control was vertical tillage. We found cover crop mixes that contained cereal rye provided the most weed control, with the chemical control being a close second. Spring oats die during the winter because of the low temperatures. The three cover crop mixes containing spring oats still provided 50% reduction in weed biomass the follow­ing spring. However, the fall tillage increased the amount of weed biomass

    Quantitative single cell determination of ERK phosphorylation and regulation in relapsed and refractory primary acute myeloid leukemia

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    : We investigated the constitutive activation of the MEK/ERK pathway in acute myelogenous leukemia (AML) via a flow cytometric technique to quantitate expression of phosphorylated ERK (p-ERK). A total of 42 AML samples (16 newly diagnosed, 26 relapsed/refractory) were analyzed. Normal bone marrow CD34+ cells (n = 10) had little or no expression of p-ERK, while G-CSF-mobilized CD34+ cells exhibited enhanced p-ERK levels. Markedly elevated p-ERK levels were found in 83.3% of the AML samples, with no differences observed between the newly diagnosed and relapsed/refractory samples. Treatment with a MEK inhibitor resulted in significantly decreased p-ERK levels in both the newly diagnosed and relapsed/refractory samples, which was associated with growth arrest, but not apoptosis induction. In summary, we defined conditions for the analysis of MAPK signaling in primary AML samples. Normal CD34+ cells expressed very low levels of p-ERK, and increased p-ERK levels were found in normal G-CSF-stimulated circulating CD34+ cells. Constitutively high p-ERK levels observed in the majority of AML samples suggest deregulation of this pathway that appears to be independent of disease status. The ability of ERK inhibition to promote growth arrest rather than apoptosis suggests that clinical trials of MEK/ERK inhibitors may be more effective when combined with chemotherapy

    Peer observation of teaching: A decoupled process

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    This article details the findings of research into the academic teaching staff experience of peer observation of their teaching practice. Peer observation is commonly used as a tool to enhance a teacher’s continuing professional development. Research participants acknowledged its ability to help develop their teaching practice, but they also reported that it could operate superficially as a tick box exercise, that its outcomes were frequently decoupled from formal staff development processes, and that its purpose and usefulness therefore seemed unclear. This article argues that the presence of decoupling reinforces the need to account for structural factors that can interact with peer observation of teaching to ensure it is a meaningful exercise for all teaching staff. It concludes that the published academic literature is perhaps guilty of overplaying the role of personal choice and individual tutor characteristics when addressing the complex issue that is staff disengagement with peer observation of teaching

    Kidney Recovery in Patients with Acute Kidney Injury Treated in Outpatient Hemodialysis or Rehabilitation Facilities

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    Rationale & Objective: Since January 2017, patients with acute kidney injury requiring dialysis (AKI-D) can be discharged to outpatient dialysis centers for continued hemodialysis (HD) support. We aimed to examine the rate of kidney recovery, time to recovery, and hospitalization-related clinical parameters associated with kidney recovery in patients with AKI-D. Study Design: Single-center prospective cohort study. Setting & Participants: 111 adult patients who were admitted to the University of Kentucky Hospital, experienced AKI-D, and were discharged with need of outpatient HD. Exposure: Hospitalization-related clinical parameters were evaluated. Outcome: Kidney recovery as a composite of being alive and no longer requiring HD or other form of kidney replacement therapy. Analytical Approach: Discrete-time survival analysis and logistic regression were used to determine adjusted probabilities of kidney recovery at prespecified time points and to evaluate clinical parameters associated with recovery. Results: 45 (41%) patients recovered kidney function, 25 (55.5%) within the first 30 days following discharge, 16 (35.5%) within 30 to 60 days, and 4 (9%) within 60 to 90 days. Adjusted probabilities of recovery were 36.7%, 27.4%, and 6.3%, respectively. Of the remaining patients, 49 (44%) developed kidney failure requiring chronic kidney replacement therapy and 17 (15%) died or went to hospice. Patients who did not recover kidney function were older, had more comorbid conditions, had lower estimated glomerular filtration rates at baseline, and received more blood transfusions during hospitalization when compared with those who recovered kidney function. Limitations: Selection bias given that patients included in the study were all eligible for AKI management with outpatient HD as part of Medicare/Medicaid services. Conclusions: At least one-third of AKI-D survivors discharged from an acute care hospital dependent on HD recovered kidney function within the first 90 days of discharge, more commonly in the first 30 days postdischarge. Future studies should elucidate clinical parameters that can inform risk classification and interventions to promote kidney recovery in this vulnerable and growing population
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