581 research outputs found

    Residual Effect of Herbicides Used in Pastures on Clover Establishment and Productivity

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    Field experiments in 2013 evaluated residual herbicide effects on ball (Trifolium nigrescens viv.) and white (Trifolium repens L.) clover. For the October planting, averaged across clovers, ground cover for 2,4-D plus aminopyralid and 2,4-D plus picloram averaged 4.4 and was less than for the nontreated (7.0). For the November and March plantings, ground cover for all herbicides was equivalent to the nontreated. Averaged across clover species and planting date, herbicide treatments except 2,4-D plus aminopyralid (4) resulted in ground cover 49/112 days after planting (DAP) equal to the non-treated (5.7). Lowest plant population 4 to 6 wk after Oct/Nov planting was observed for 2,4-D plus aminopyralid (6.3) and 2,4-D plus picloram (7.3). Only 2,4-D plus aminopyralid resulted in yield reduction from the nontreated (29.8%). Field experiments also evaluated simulated residual effects of fluroxypyr plus triclopyr and 2, 4-D plus picloram on ball (Trifolium nigrescens viv.), white (Trifolium repens L.), crimson (Trifolium incarnatum L.) and red (Trifolium pretense L.) clover. For all clovers, when averaged across herbicide rates, plant population 214/217 and ground cover 86/87 DAP was equivalent for fluroxypyr plus triclopyr and the non-treated and greater than 2,4-D plus picloram. Averaged across herbicide rates, clover height was equivalent for fluroxypyr plus triclopyr and the non-treated. 2,4-D plus picloram reduced clover height 67 to 88% from the non-treated. Ground cover 161/196 DAP, when averaged across clovers, for all rates of fluroxypyr plus triclopyr was equivalent to the non-treated. All rates of 2,4-D plus picloram were reduced compared to the non-treated (1.4 to 4.0 vs 7.9). Averaged across clovers, plant height following all rates of fluroxypyr plus triclopyr was equivalent to the non-treated (14.2 to 14.3 vs 15.3 cm) and greater than 2,4-D plus picloram. Compared with the non-treated, 2,4-D plus picloram at 25, 38, and 50% x rates reduced height 58, 76, and 85% respectively. Averaged across clover species, yield for fluroxypyr plus triclopyr at all rates was equivalent to the non-treated (2624.0 to 2839.7 vs 2811.9 kg/ha). Compared with the non-treated, 2,4-D plus picloram at 25, 38, and 50% x rate reduced yield 65,89, and 99%, respectively

    Multimodal MRI Neuroimaging Biomarkers for Cognitive Normal Adults, Amnestic Mild Cognitive Impairment, and Alzheimer's Disease

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    Multimodal magnetic resonance imaging (MRI) techniques have been developed to noninvasively measure structural, metabolic, hemodynamic and functional changes of the brain. These advantages have made MRI an important tool to investigate neurodegenerative disorders, including diagnosis, disease progression monitoring, and treatment efficacy evaluation. This paper discusses recent findings of the multimodal MRI in the context of surrogate biomarkers for identifying the risk for AD in normal cognitive (NC) adults, brain anatomical and functional alterations in amnestic mild cognitive impairment (aMCI), and Alzheimer's disease (AD) patients. Further developments of these techniques and the establishment of promising neuroimaging biomarkers will enhance our ability to diagnose aMCI and AD in their early stages and improve the assessment of therapeutic efficacy in these diseases in future clinical trials

    Thalamic medial dorsal nucleus atrophy in medial temporal lobe epilepsy: A VBM meta-analysis

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    Purpose: Medial temporal lobe epilepsy (MTLE) is associated with MTLE network pathology within and beyond the hippocampus. The purpose of this meta-analysis was to identify consistent MTLE structural change to guide subsequent targeted analyses of these areas. Methods: We performed an anatomic likelihood estimation (ALE) meta-analysis of 22 whole-brain voxel-based morphometry experiments from 11 published studies. We grouped these experiments in three ways. We then constructed a meta-analytic connectivity model (MACM) for regions of consistent MTLE structural change as reported by the ALE analysis. Key findings: ALE reported spatially consistent structural change across VBM studies only in the epileptogenic hippocampus and the bilateral thalamus; within the thalamus, the medial dorsal nucleus of the thalamus (MDN thalamus) represented the greatest convergence (Pb0.05 corrected for multiple comparisons). The subsequent MACM for the hippocampus and ipsilateral MDN thalamus demonstrated that the hippocampus and ipsilateral MDN thalamus functionally co-activate and are nodes within the same network, suggesting that MDN thalamic damage could result from MTLE network excitotoxicity. Significance: Notwithstanding our large sample of studies, these findings aremore restrictive thanprevious reports and demonstrate the utility of our inclusion filters and of recently modified meta-analyticmethods in approximating clinical relevance. Thalamic pathology is commonly observed in animal and human studies, suggesting it could be a clinically useful indicator. Thalamus-specific research as a clinical marker awaits further investigation

    Estimating the prevalence of missing experiments in a neuroimaging meta-analysis.

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    Coordinate-based meta-analyses (CBMA) allow researchers to combine the results from multiple functional magnetic resonance imaging experiments with the goal of obtaining results that are more likely to generalize. However, the interpretation of CBMA findings can be impaired by the file drawer problem, a type of publication bias that refers to experiments that are carried out but are not published. Using foci per contrast count data from the BrainMap database, we propose a zero-truncated modeling approach that allows us to estimate the prevalence of nonsignificant experiments. We validate our method with simulations and real coordinate data generated from the Human Connectome Project. Application of our method to the data from BrainMap provides evidence for the existence of a file drawer effect, with the rate of missing experiments estimated as at least 6 per 100 reported. The R code that we used is available at https://osf.io/ayhfv/

    Future Energy Solutions for North St. Paul: Exploring Net Zero Carbon

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    Presentation completed by students in PA 5271, taught by Dr. Elizabeth Wilson in fall 2013.This project was completed as part of the 2013-2014 Resilient Communities Project (rcp.umn.edu) partnership with the City of North St. Paul. The City of North St. Paul is unique in that it operates its own electric utility, in cooperation with Minnesota Municipal Power Agency. The city sought assistance investigating and providing information to residents, businesses, and elected officials about alternative energy and energy conservation initiatives, as well as identifying strategies for dedicating electric utility revenue toward green energy initiatives such as wind, solar, and geothermal. North St. Paul Electric Utility Director Brian Frandle partnered with five teams of students in PA 5271: Energy and Environmental Policy, to investigate such opportunities. A presentation prepared by student group 5 is available. A video produced by the students is available at https://youtu.be/rUPxwq_EG-Y. (Student deliverables from the other four student teams are catalogued separately.).This project was supported by the Resilient Communities Project (RCP), a program at the University of Minnesota whose mission is to connect communities in Minnesota with U of MN faculty and students to advance local sustainability and resilience through collaborative, course-based projects. RCP is a program of the Center for Urban and Regional Affairs (CURA). More information at http://www.rcp.umn.edu

    Progressive Bidirectional Age-Related Changes in Default Mode Network Effective Connectivity across Six Decades

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    The default mode network (DMN) is a set of regions that is tonically engaged during the resting state and exhibits task-related deactivation that is readily reproducible across a wide range of paradigms and modalities. The DMN has been implicated in numerous disorders of cognition and, in particular, in disorders exhibiting age-related cognitive decline. Despite these observations, investigations of the DMN in normal aging are scant. Here, we used blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) acquired during rest to investigate age-related changes in functional connectivity of the DMN in 120 healthy normal volunteers comprising six, 20-subject, decade cohorts (from 20–29 to 70–79). Structural equation modeling (SEM) was used to assess age-related changes in inter-regional connectivity within the DMN. SEM was applied both using a previously published, meta-analytically derived, node-and-edge model, and using exploratory modeling searching for connections that optimized model fit improvement. Although the two models were highly similar (only 3 of 13 paths differed), the sample demonstrated significantly better fit with the exploratory model. For this reason, the exploratory model was used to assess age-related changes across the decade cohorts. Progressive, highly significant changes in path weights were found in 8 (of 13) paths: four rising, and four falling (most changes were significant by the third or fourth decade). In all cases, rising paths and falling paths projected in pairs onto the same nodes, suggesting compensatory increases associated with age-related decreases. This study demonstrates that age-related changes in DMN physiology (inter-regional connectivity) are bidirectional, progressive, of early onset and part of normal aging

    Progressive Bidirectional Age-Related Changes in Default Mode Network Effective Connectivity across Six Decades

    Get PDF
    The default mode network (DMN) is a set of regions that is tonically engaged during the resting state and exhibits task-related deactivation that is readily reproducible across a wide range of paradigms and modalities. The DMN has been implicated in numerous disorders of cognition and, in particular, in disorders exhibiting age-related cognitive decline. Despite these observations, investigations of the DMN in normal aging are scant. Here, we used blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) acquired during rest to investigate age-related changes in functional connectivity of the DMN in 120 healthy normal volunteers comprising six, 20-subject, decade cohorts (from 20–29 to 70–79). Structural equation modeling (SEM) was used to assess age-related changes in inter-regional connectivity within the DMN. SEM was applied both using a previously published, meta-analytically derived, node-and-edge model, and using exploratory modeling searching for connections that optimized model fit improvement. Although the two models were highly similar (only 3 of 13 paths differed), the sample demonstrated significantly better fit with the exploratory model. For this reason, the exploratory model was used to assess age-related changes across the decade cohorts. Progressive, highly significant changes in path weights were found in 8 (of 13) paths: four rising, and four falling (most changes were significant by the third or fourth decade). In all cases, rising paths and falling paths projected in pairs onto the same nodes, suggesting compensatory increases associated with age-related decreases. This study demonstrates that age-related changes in DMN physiology (inter-regional connectivity) are bidirectional, progressive, of early onset and part of normal aging

    Progranulin is Neurotrophic In Vivo and Protects against a Mutant TDP-43 Induced Axonopathy

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    Mislocalization, aberrant processing and aggregation of TAR DNA-binding protein 43 (TDP-43) is found in the neurons affected by two related diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal lobe dementia (FTLD). These TDP-43 abnormalities are seen when TDP-43 is mutated, such as in familial ALS, but also in FTLD, caused by null mutations in the progranulin gene. They are also found in many patients with sporadic ALS and FTLD, conditions in which only wild type TDP-43 is present. The common pathological hallmarks and symptomatic cross over between the two diseases suggest that TDP-43 and progranulin may be mechanistically linked. In this study we aimed to address this link by establishing whether overexpression of mutant TDP-43 or knock-down of progranulin in zebrafish embryos results in motor neuron phenotypes and whether human progranulin is neuroprotective against such phenotypes. Mutant TDP-43 (A315T mutation) induced a motor axonopathy characterized by short axonal outgrowth and aberrant branching, similar, but more severe, than that induced by mutant SOD1. Knockdown of the two zebrafish progranulin genes, grna and grnb, produced a substantial decrease in axonal length, with knockdown of grna alone producing a greater decrease in axonal length than grnb. Progranulin overexpression rescued the axonopathy induced by progranulin knockdown. Interestingly, progranulin also rescued the mutant TDP-43 induced axonopathy, whilst it failed to affect the mutant SOD1-induced phenotype. TDP-43 was found to be nuclear in all conditions described. The findings described here demonstrate that progranulin is neuroprotective in vivo and may have therapeutic potential for at least some forms of motor neuron degeneration
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