scholarly journals Contemporary evolution of maize landraces and their wild relatives influenced by gene flow with modern maize varieties

2019 ◽  
Vol 116 (42) ◽  
pp. 21302-21311 ◽  
Author(s):  
Idalia C. Rojas-Barrera ◽  
Ana Wegier ◽  
José de Jesús Sánchez González ◽  
Gregory L. Owens ◽  
Loren H. Rieseberg ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genotyping By Sequencing ◽  
Time Frame ◽  
Wild Relatives ◽  
Maize Varieties ◽  
Before And After ◽  
Modern Maize ◽  
Maize Landraces ◽  
Genetic Pools ◽  
The Impact

Mexico is recognized as the center of origin and domestication of maize. Introduction of modern maize varieties (MVs) into Mexico raised concerns regarding the possible effects of gene flow from MVs into maize landraces (LRs) and their wild relatives (WRs), teosintes. However, after more than 60 y from the release of the first MVs, the impact of the sympatry with LRs and their WRs has not been explored with genetic data. In this work, we assessed changes in the genomes of 7 maize LRs and 2 WR subspecies from collections spanning over 70 y. We compared the genotypes obtained by genotyping by sequencing (GBS) for LRs and WRs before and after the adoption of MVs, and observed introgression from sympatric MVs into LRs and into the WR Zea mays ssp. mexicana sampled after the year 2000. We also found a decrease in the paired divergence index (FST) between MV-LR and MV-WR over the same time frame. Moreover, we determined that LR genetic diversity increased after 2000, probably as a result of gene flow from MVs introduced in the 1990s. Our findings allowed us to identify ongoing changes in the domesticated and wild maize genetic pools, and concur with previous works that have evaluated short-term gene flow from MVs into LRs in other crops. Our approach represents a useful tool for tracking evolutionary change in wild and domesticated genetic resources, as well as for developing strategies for their conservation.

scholarly journals Maths Sparks engagement programme: investigating the impact on under-privileged pupils’ attitudes towards mathematics

2020 ◽  
Author(s):  
Aoibhinn Ni Shuilleabhain ◽  
Anthony Cronin ◽  
Mark Prendergast
Keyword(s):  
Social Research ◽  
Time Frame ◽  
Mathematics Students ◽  
Undergraduate Mathematics ◽  
High Stakes ◽  
Mathematical Concepts ◽  
Attitudes Towards Mathematics ◽  
Before And After ◽  
The Subject ◽  
The Impact

Abstract In this paper we explore the attitudes of under-privileged secondary school pupils in Ireland towards mathematics and investigate the impact of attending a 4-week engagement programme on these attitudes. The pupils involved in this research attended schools recognized by the Department of Education & Skills as socio-economically deprived. Pupils attending these schools, known as Delivering Equality of Opportunity in Schools (DEIS), are 40% less likely than their counterparts in non-DEIS schools to pursue mathematics at a higher level in state examinations (Smyth, E., Mccoy, S. & Kingston, G., 2015, Learning From the Evaluation of DEIS. Dublin: Economic and Social Research Institute). However, little research has reported on these pupils’ experiences of and attitudes towards mathematics at senior secondary level. An engagement programme entitled ‘Maths Sparks’ was purposefully designed for secondary pupils from DEIS schools, with the aim of positively influencing their attitudes towards and confidence in mathematics. The programme consisted of weekly out-of-school workshops exploring extra-curricular mathematics topics, designed and delivered by undergraduate mathematics students. Questionnaires were utilized to evaluate pupils’ attitudes towards mathematics before and after their participation in the programme. Despite its relatively short time frame, qualitative and quantitative analysis suggests an increase in participating pupils’ attitudes towards, enjoyment of and self-confidence in mathematics due to their participation in the programme. Findings also suggest that while these pupils liked the subject of mathematics, their experience of learning the subject in school was not always positive and was sometimes hindered by the absence of higher-level mathematics as an option in school. The high-stakes examination content and teachers’ beliefs in the ability of their students also sometimes negatively impacted learners’ intentions to pursue mathematics at a higher level. Findings suggest that longitudinal mathematics engagement programmes, which focus on problem solving, involve extra-curricular mathematical concepts and are presented by undergraduate mathematics students, may provide a valuable way of positively impacting pupils’ intentions to pursue the subject.

scholarly journals Archaeological Central American maize genomes suggest ancient gene flow from South America

2020 ◽  
Vol 117 (52) ◽  
pp. 33124-33129
Author(s):  
Logan Kistler ◽  
Heather B. Thakar ◽  
Amber M. VanDerwarker ◽  
Alejandra Domic ◽  
Anders Bergström ◽  
...  
Keyword(s):  
Gene Flow ◽  
South America ◽  
Central America ◽  
Central American ◽  
Morphological Data ◽  
Radiocarbon Dates ◽  
Rock Shelter ◽  
Maize Varieties ◽  
American Maize ◽  
Modern Maize

Maize (Zea mays ssp. mays) domestication began in southwestern Mexico ∼9,000 calendar years before present (cal. BP) and humans dispersed this important grain to South America by at least 7,000 cal. BP as a partial domesticate. South America served as a secondary improvement center where the domestication syndrome became fixed and new lineages emerged in parallel with similar processes in Mesoamerica. Later, Indigenous cultivators carried a second major wave of maize southward from Mesoamerica, but it has been unclear until now whether the deeply divergent maize lineages underwent any subsequent gene flow between these regions. Here we report ancient maize genomes (2,300–1,900 cal. BP) from El Gigante rock shelter, Honduras, that are closely related to ancient and modern maize from South America. Our findings suggest that the second wave of maize brought into South America hybridized with long-established landraces from the first wave, and that some of the resulting newly admixed lineages were then reintroduced to Central America. Direct radiocarbon dates and cob morphological data from the rock shelter suggest that more productive maize varieties developed between 4,300 and 2,500 cal. BP. We hypothesize that the influx of maize from South America into Central America may have been an important source of genetic diversity as maize was becoming a staple grain in Central and Mesoamerica.

scholarly journals Impacts of land management on the resilience of Mediterranean dry forests to fire

2016 ◽  
Author(s):  
Matteo Jucker Riva ◽  
Gudrun Schwilch ◽  
Hanspeter Liniger ◽  
Alejandro Valdecantos
Keyword(s):  
Land Management ◽  
Management Practices ◽  
Fire Regime ◽  
Management Strategies ◽  
Time Frame ◽  
Mediterranean Forests ◽  
Before And After ◽  
History Of ◽  
Time Specific ◽  
The Impact

Wildfires have always been a part of the history of Mediterranean forests. However, forest regeneration after a wildfire is not certain. It depends on many factors, some of which may be influenced by land management activities. Failure of regeneration will cause a regime shift in the ecosystem, reducing the provision of ecosystem services and ultimately leading to desertification. How can we increase Mediterranean forests’ resilience to fire? To answer this question, we did a literature review, investigating chains of processes that allow forests to regenerate (which we label “regeneration mechanisms”), and assessed the impact of selected management practices documented in the WOCAT database on the regeneration mechanisms. We identified three distinct regeneration mechanisms that enable Mediterranean forests to recover, as well as the time frame before and after a fire in which they are at work, and factors that can hinder or support resilience. The three regeneration mechanisms enabling a forest to regenerate after a fire consist of regeneration (1) from a seed bank; (2) from resprouting individuals; and (3) from unburned plants that escaped the fire. Management practices were grouped into four categories: (1) fuel breaks, (2) fuel management, (3) afforestation, and (4) mulching. We assessed how and under what conditions land management modifies the ecosystem’s resilience. The results show that land management influences resilience by interacting with resilience mechanisms before and after the fire, and not just by modifying the fire regime. Our analysis demonstrates a need for adaptive – i.e. context- and time-specific – management strategies.

P1398EFFECTS OF CONVERTING FROM CINACALCET TO ETELCALCETIDE

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Sofia Homem Melo Marques ◽  
Pablo Alija
Keyword(s):  
Vitamin D ◽  
Secondary Hyperparathyroidism ◽  
Time Frame ◽  
Chronic Hemodialysis ◽  
Vitamin D Analogues ◽  
Laboratory Values ◽  
Before And After ◽  
Calcium Phosphorus ◽  
The Mean ◽  
The Impact

Abstract Background and Aims Secondary hyperparathyroidism is a common problem in patients undergoing chronic hemodialysis and its treatment includes vitamin D analogs and calcimimetics which act upon the calcium-sensing receptor. Etelcalcetide was introduced as an intravenous calcimimetic easy to administer at the end of the hemodialysis session with improved adherence. Hypocalcemic episodes have raised some concerns although this side effect is not unanimously described. As an institutional policy most patients from 2 hemodialysis units were switched from cinacalcet to etelcalcetide between July 2017 and January 2018. We aimed at evaluating the impact of this conversion upon laboratory values and ongoing medication. Method We collected data from patients in 2 hemodialysis units including monthly serum values of calcium, phosphorus, hemoglobin and albumin, quarterly parathormone (PTH) values from 3 months previous to conversion until 3 months post-conversion as well as the calcimimetic dose during the same time frame. Descriptive statistics concerning mean and median values of the previous 3 and next 3 months following conversion were used. A paired sample t-test was performed to compare values before and after conversion. Results Of the approximately 200 patients, 22 were on cinacalcet and were switched to etelcalcetide. These had a mean age of 66.9 years and included 9 women and 8 diabetics. Mean PTH value before conversion was 728±391 (range 371-1900pg/mL) and did not differ significantly from that after conversion 717±330 (p=0.9). No significant statistical difference between values before and after conversion was found for serum calcium (9.3±0.5 vs 9.2±0.6; p=0.43), phosphorus (5.4±0.8 vs 5.1±1.0; p=0.15), albumin (4.1±0.2 vs 4.1±0.2; p=0.83) and hemoglobin (11.3±0.8 vs 11.4±0.9; p=0.50). The mean number of hypocalcemic values during the 3 months before and after conversion was identical (0.6±1 vs 0.6±0.9; p=0.86). The median cinacalcet dose on the month before conversion was 30mg/day (IQR 22.5) and the median etelcalcetide dose at conversion was 2.5mg three times per week (IQR 1.9). The conversion factor was 27mg cinacalcet: 1mg etelcalcetide, because even patients on high cinacalcet doses were initially started at low etelcalcetide doses. However, at 3 months following conversion, the median etelcalcetide dose was 8.75 (IQR 7.5). The doses of erythropoiesis-stimulating agents (ESA), vitamin D analogues and phosphorus binders were not significantly affected. Conclusion Switching from cinacalcet to etelcalcetide in all patients on hemodialysis in a particular institution did not change laboratory values or increased the number of hypocalcemic measurements. The etelcalcetide dose was adjusted up for the first 3 months and the mean PTH value did not change significantly. Treatment with ESA, vitamin D analogues and phosphorus binders remained unchanged after conversion. Secondary hyperparathyroidism is a chronic condition and etelcalcetide provides a useful means to control it with an easy administration regimen.

scholarly journals OP0213 THE IMPACT OF TNFΑ INHIBITORS ON GLUCOCORTICOIDS USE AMONG PATIENTS WITH ARTHRITIS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 132.2-133
Author(s):  
R. Hafthorsdottir ◽  
A. Gunnarsdottir ◽  
T. Love ◽  
G. Gröndal ◽  
B. Gudbjornsson
Keyword(s):  
Osteoporosis Treatment ◽  
Time Frame ◽  
Topical Steroids ◽  
Defined Daily Dose ◽  
Tnfα Inhibitors ◽  
Before And After ◽  
Osteoporosis Prophylaxis ◽  
The Impact ◽  
Number Of Individuals

Background:Glucocorticoid steroid (GC) use among patients with arthritis is common. The introduction of TNFα inhibitors (TNFi) has been a breakthrough in the treatment of arthritis leading to remission for many patients. However, there is scarce information on the impact of TNFi on the use of GC among patients with inflammatory joint diseases.Objectives:To explore oral GC use in patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), and axial spondyloarthritis (axSpA) before and after the initiation of TNFi therapy. Furthermore, to evaluate if patients on long term GC treatment were receiving active preventive osteoporosis treatment and how treatment with TNFi affected the use of topical steroids in patients with PsA.Methods:Clinical data on patients with RA, PsA and axSpA who initiated TNFi therapy with etanercept, infliximab, adalimumab or golimumab for the first time between 2005-2015 was collected from the ICEBIO registry. ICEBIO is a nationwide registry on all patients treated with biologics for rheumatologic disorders in Iceland. The use of oral GC, topical steroids and bisphosphonates was collected from the Icelandic Prescription Medicines Registry (IPMR) for a period of four years, two years before and after the initiation of TNFi. Medication use was then evaluated by counting the number of individuals receiving a medication in a given year, the total number of prescriptions, and the defined daily dose (DDD). Five controls were randomly selected from IPMR and matched on age, sex and time frame.Results:621 patients with RA, PsA or axSpA received 2630 prescriptions (4.2 prescription per patient; 3105 controls received 1337 prescriptions or 0.4 prescription per individual) for GC during the study period. GC use varied between patient groups (Figure 1). The total GC use (DDD) doubled over the two-year period leading up to TNFi treatment but decreased sharply after the initiation of TNFi. The number of individuals on GC decreased by one third after initiating TNFi therapy and the majority of those who continued GC treatment were patients with RA (Figure 1). Of those patients on long term GC treatment (>7.5 mg/day for three months) 38% were receiving bone protective therapy against corticosteroid induced osteoporosis. The use of topical steroids decreased by half among PsA patients and one third discontinued the treatment after initiating TNFi (Figure 2).Conclusion:TNFi therapy does impact GC use among patients with arthritides, however a large portion of RA patients are still on GC two years after initiating TNFi therapy. Better osteoporosis prophylaxis and treatment is warranted for those patients on long term GCDisclosure of Interests:Rebekka Hafthorsdottir: None declared, Anna Gunnarsdottir: None declared, Thorvardur Love: None declared, Gerdur Gröndal: None declared, Björn Gudbjornsson Speakers bureau: Novartis and Amgen

scholarly journals Do Individuals Skimp on Health Care After Spouse’s Dementia Diagnosis?

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. 17-18
Author(s):  
Yi Chen
Keyword(s):  
Health Care ◽  
Fixed Effects ◽  
Time Frame ◽  
Policy Support ◽  
Dementia Diagnosis ◽  
Doctor Visits ◽  
Before And After ◽  
Flu Shot ◽  
Socio Demographic Factors ◽  
The Impact

Abstract Dementia is a costly disease that places great burden on individuals and families. The substantial time and financial resources taken away by living with persons with dementia (PWDs) may make their spouses forgo essential health care, thus deteriorating long-term health and increasing downstream healthcare costs. However, such negative externality is understudied. This paper studied the impacts of spouse's incident dementia diagnosis on an individual's use of needed care, defined as annual flu shot and regular doctor visits for those with preexisting conditions. Using HRS linked to Medicare claims, I employed a fixed effects approach to compare the use of flu shot and doctor visit during 1 year before and after the index, for individuals whose spouse had dementia (N=691) and otherwise similar controls (N=5,073). After adjusting for time-varying health, caregiving roles, and other socio-demographic factors, spouse’s dementia onset was associated with greater likelihood of getting flu shot and seeing doctors. Among those transitioning into caregiving, spouses of PWDs had a marginally higher risk of skimping on doctor visits, compared to controls (p=0.053). In this broadly representative sample, there lacks evidence for rationed health care ensuing spouse’s dementia incidence, at least within a 1-year time frame. However, for new spousal caregivers, the impact of dementia is more profound and complex than deprivation of time. This group may face a trade-off between caring for spouses with dementia and caring for themselves, for whom policy support merits further study and consideration.

Abstract TP242: A Brief Educational Intervention Improves Paramedic Stroke Knowledge

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
John A Oostema ◽  
Todd Chassee ◽  
Mel Oakley ◽  
Mathew J Reeves
Keyword(s):  
Educational Intervention ◽  
Systems Of Care ◽  
Quality Care ◽  
Time Frame ◽  
Before And After ◽  
Baseline Knowledge ◽  
On Line ◽  
Stroke Systems Of Care ◽  
The Impact ◽  
Stroke Knowledge

Introduction: Emergency Medical Services (EMS) are an important component of stroke systems of care. EMS transport has been associated with faster emergency department (ED) stroke evaluations and higher t-PA delivery rates, especially among EMS recognized cases with hospital prenotification. However, delivery of high quality care including hospital prenotification requires that paramedics received regular education and training to improve their ability to identify and treat stroke cases. Methods: We identified opportunities for improvement in EMS care of suspect stroke patients through a review of local EMS stroke-related performance data and focus group discussions with paramedics. We then developed a 20-minute online educational module that reviewed basic stroke pathophysiology, discussed acute stroke therapies, and stressed the importance of performing stroke screening examinations and hospital prenotification for suspect stroke cases. The training was provided to all paramedics in a single agency. Scores on 10 item multiple-choice assessment were compared before and after receipt of the online training module using Fisher Exact tests and Wilcoxon Rank Sum Tests. Results: A total of 40 paramedics underwent the training. Overall quiz scores improved from a median of 9 (interquartile range [IQR] 7 to 9) to 10 (IQR 9 to 10, p=0.0002). Prior to training, only 43% of paramedics correctly identified 4.5 hours as the window for t-PA treatment, with 43% choosing 6 hours. Correct t-PA window identification improved significantly following education (43% to 87.5%, p<0.0001). Improvements were also seen for questions regarding the most common presenting complaints among EMS missed strokes (72.5% to 90%) and the recommended time frame for verbal hospital prenotification (80% to 95%), although these differences were not statistically significant. Conclusions: Overall, paramedics demonstrated good baseline knowledge regarding stroke, however important misconceptions regarding the time frame for t-PA eligibility were common. A brief, on-line educational intervention improved stroke knowledge. Further work is needed to determine the impact of stroke education on real world paramedic performance.

scholarly journals Genome wide analysis of Ga1-s modifiers in maize

2019 ◽  
Author(s):  
Preston Hurst ◽  
Zhikai Liang ◽  
Christine Smith ◽  
Melinda Yerka ◽  
Brandi Sigmon ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genotyping By Sequencing ◽  
The United States ◽  
Reproductive Barrier ◽  
Sequencing Data ◽  
Genetic Incompatibility ◽  
Agricultural Plant ◽  
Dent Corn ◽  
Using Data ◽  
The Impact

ABSTRACTA one way reproductive barrier exists between most popcorn varieties and dent corn varieties grown in the United States. This barrier is predominantly controlled by the ga1 locus. Using data from a diverse population of popcorn accessions pollinated by a dent corn tester, we found that the non-reciprocal pollination barrier conferred by ga1 is more complex than previously described. Individual accessions ranged from 0% to 100% compatible with dent corn pollen. Using conventional genotyping-by-sequencing data from 371 popcorn accessions carrying Ga1-s, seven significant modifiers of dent pollen compatibility were identified on five chromosomes. One locus may either be a nonfunctional ga1 allele present within popcorn, or second necessary gene for the reproductive barrier in genetic linkage with ga1, while the other modifiers are clearly genetically unlinked. The existence of ga1 modifiers segregating in a popcorn genetic background may indicate selective pressure to allow gene flow between populations, which should be incorporated into future models of the impact of genetic incompatibility loci on gene flow in natural and agricultural plant populations.

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