2,437 research outputs found

    Promoting Fertilizer Use in Africa: Current Issues and Empirical Evidence from Malawi, Zambia, and Kenya

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    It is generally agreed that increasing agricultural productivity is critical to stimulating the rate of economic growth in Africa. There are many important and often complementary determinants of agricultural productivity. In this brief and the full paper it draws from, the focus is on fertilizer and improved seed, without intending to imply that they are the only or most significant productivity determinants.fertilizer, Africa, Malawi, Zambia, Kenya, Crop Production/Industries, Food Security and Poverty, Q18,

    Promoting Fertilizer Use in Africa: Current Issues and Empirical Evidence from Malawi, Zambia, and Kenya

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    This study was funded jointly by the Regional Strategic Agricultural Knowledge Support System (Re-SAKSS) for Southern Africa, based at International Water Management Institute, Pretoria, South Africa, and by the United States Agency for International Development's Africa Bureau. Much of the data and analysis reported in this study was carried out under the Tegemeo Agricultural Monitoring and Policy Analysis Project, funded by USAID/Kenya; the Food Security Research Project/Markets, Trade and Enabling Environment (MATEP) Program, funded by USAID/Zambia and the Swedish International Development Agency; and by the DFID and USAID offices in Lilongwe, Malawi.fertilizer, Africa, Malawi, Zambia, Kenya, Crop Production/Industries, Q18,

    A molecular‐level perspective on the frequency, distribution, and consequences of messenger RNA modifications

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    Cells use chemical modifications to alter the sterics, charge, and conformations of large biomolecules, modulating their biogenesis, function, and stability. Until recently post‐transcriptional RNA modifications were thought to be largely limited to nonprotein coding RNA species. However, this dogma has rapidly transformed with the discovery of a host of modifications in protein coding messenger RNAs (mRNAs). Recent advancements in genome‐wide sequencing technologies have enabled the identification of mRNA modifications as a potential new frontier in gene regulation—leading to the development of the epitranscriptome field. As a result, there has been a flurry of multiple groundbreaking discoveries, including new modifications, nucleoside modifying enzymes (“writers” and “erasers”), and RNA binding proteins that recognize chemical modifications (“readers”). These discoveries opened the door to understanding how post‐transcriptional mRNA modifications can modulate the mRNA lifecycle, and established a link between the epitranscriptome and human health and disease. Despite a rapidly growing recognition of their importance, fundamental questions regarding the identity, prevalence, and functional consequences of mRNA modifications remain to be answered. Here, we highlight quantitative studies that characterize mRNA modification abundance, frequency, and interactions with cellular machinery. As the field progresses, we see a need for the further integration of quantitative and reductionist approaches to complement transcriptome wide studies in order to establish a molecular‐level framework for understanding the consequences of mRNA chemical modifications on biological processes.This article is categorized under:RNA Structure and Dynamics > RNA Structure, Dynamics and ChemistryRNA Processing > RNA Editing and ModificationThe integration of biochemical, structural, and transcriptome wide approaches is shaping a quantitative framework for understanding the biological consequences of mRNA modifications.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155973/1/wrna1586.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155973/2/wrna1586_am.pd

    Neonatal NMDA receptor blockade disrupts spike timing and glutamatergic synapses in fast spiking interneurons in a NMDA receptor hypofunction model of schizophrenia

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    The dysfunction of parvalbumin-positive, fast-spiking interneurons (FSI) is considered a primary contributor to the pathophysiology of schizophrenia (SZ), but deficits in FSI physiology have not been explicitly characterized. We show for the first time, that a widely-employed model of schizophrenia minimizes first spike latency and increases GluN2B-mediated current in neocortical FSIs. The reduction in FSI first-spike latency coincides with reduced expression of the Kv1.1 potassium channel subunit which provides a biophysical explanation for the abnormal spiking behavior. Similarly, the increase in NMDA current coincides with enhanced expression of the GluN2B NMDA receptor subunit, specifically in FSIs. In this study mice were treated with the NMDA receptor antagonist, MK-801, during the first week of life. During adolescence, we detected reduced spike latency and increased GluN2B-mediated NMDA current in FSIs, which suggests transient disruption of NMDA signaling during neonatal development exerts lasting changes in the cellular and synaptic physiology of neocortical FSIs. Overall, we propose these physiological disturbances represent a general impairment to the physiological maturation of FSIs which may contribute to schizophrenia-like behaviors produced by this model

    Copy Number Alterations and Methylation in Ewing's Sarcoma

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    Ewing's sarcoma is the second most common bone malignancy affecting children and young adults. The prognosis is especially poor in metastatic or relapsed disease. The cell of origin remains elusive, but the EWS-FLI1 fusion oncoprotein is present in the majority of cases. The understanding of the molecular basis of Ewing's sarcoma continues to progress slowly. EWS-FLI1 affects gene expression, but other factors must also be at work such as mutations, gene copy number alterations, and promoter methylation. This paper explores in depth two molecular aspects of Ewing's sarcoma: copy number alterations (CNAs) and methylation. While CNAs consistently have been reported in Ewing's sarcoma, their clinical significance has been variable, most likely due to small sample size and tumor heterogeneity. Methylation is thought to be important in oncogenesis and balanced karyotype cancers such as Ewing's, yet it has received only minimal attention in prior studies. Future CNA and methylation studies will help to understand the molecular basis of this disease

    UC-15 Malware Analysis Using Reverse Engineering

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    The motivation for this project is driven by evaluation of the different tools on the market that allow for breaking down executables or binary files, and understanding what the malware is doing. By reverse-engineering the malware, we can understand its impact and how to protect against it. Our focus is to understand where different tools are stronger than others, as well as understand the evolving landscape of malware and security overall. For this capstone project, we utilized two different tools and many sample malware files. The methods used to debug the malware are detailed in our milestone two report and will be expanded upon in our final presentation. At this point, we\u27ve found the tool WinDbg to be the most versatile for binary and executable debugging. We also evaluated IDA Pro, and understand the many ways in which its graphical display of data and relationships, equips a researcher with the necessary tools and information to walk through an executable. Our focus in milestone 3 is to expand our documentation and guide on malware debugging to the point that it provides a user the full breadth of information and steps needed to start from scratch and end with a broken apart piece of malware. We provided much of this as part of the milestone 2 presentation and report, but we will continue to build on it so it\u27s a useful how-to guide for anyone trying to debug a piece of malicious code.Advisors(s): Dr. Ying Xie [email protected](s): SecurityIT 498

    The Safety and Efficacy of Phage Therapy for Infections in Cardiac and Peripheral Vascular Surgery:A Systematic Review

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    New approaches to managing infections in cardiac and peripheral vascular surgery are required to reduce costs to patients and healthcare providers. Bacteriophage (phage) therapy is a promising antimicrobial approach that has been recommended for consideration in antibiotic refractory cases. We systematically reviewed the clinical evidence for phage therapy in vascular surgery to support the unlicensed use of phage therapy and inform future research. Three electronic databases were searched for articles that reported primary data about human phage therapy for infections in cardiac or peripheral vascular surgery. Fourteen reports were eligible for inclusion, representing 40 patients, among which an estimated 70.3% of patients (n = 26/37) achieved clinical resolution. A further 10.8% (n = 4/37) of patients showed improvement and 18.9% (n = 7/37) showed no improvement. Six of the twelve reports that commented on the safety of phage therapy did not report adverse effects. No adverse effects documented in the remaining six reports were directly linked to phages but reflected the presence of manufacturing contaminants or release of bacterial debris following bacterial lysis. The reports identified by this review suggest that appropriately purified phages represent a safe and efficacious treatment option for infections in cardiac and peripheral vascular surgery.</p

    The Safety and Efficacy of Phage Therapy for Infections in Cardiac and Peripheral Vascular Surgery:A Systematic Review

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    New approaches to managing infections in cardiac and peripheral vascular surgery are required to reduce costs to patients and healthcare providers. Bacteriophage (phage) therapy is a promising antimicrobial approach that has been recommended for consideration in antibiotic refractory cases. We systematically reviewed the clinical evidence for phage therapy in vascular surgery to support the unlicensed use of phage therapy and inform future research. Three electronic databases were searched for articles that reported primary data about human phage therapy for infections in cardiac or peripheral vascular surgery. Fourteen reports were eligible for inclusion, representing 40 patients, among which an estimated 70.3% of patients (n = 26/37) achieved clinical resolution. A further 10.8% (n = 4/37) of patients showed improvement and 18.9% (n = 7/37) showed no improvement. Six of the twelve reports that commented on the safety of phage therapy did not report adverse effects. No adverse effects documented in the remaining six reports were directly linked to phages but reflected the presence of manufacturing contaminants or release of bacterial debris following bacterial lysis. The reports identified by this review suggest that appropriately purified phages represent a safe and efficacious treatment option for infections in cardiac and peripheral vascular surgery.</p

    The effects of golf course runoff on macroinvertebrates and nutrient levels in the Carp Lake and Maple Rivers.

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    General EcologyThe effect of fertilizer runoff from nonpoint sources is an issue for water quality. This study focused on two rivers in Northern Lower Michigan, the Maple River and the Carp Lake River and the possible effects of fertilizer runoff from golf courses adjacent to those rivers. The purpose was to measure the proportion of macroinvertebrates, particularly Ephemeroptera, Plecoptera, and Trichoptera, which serve as indicators of aquatic ecosystem health and also to measure nutrient levels on the rivers to determine water quality. Samples of macroinvertebrates and nutrients were taken at three locations on each river; upstream from the golf course, at the golf course, and downstream from the golf course. Temperature, pH, alkalinity, conductivity, chlorophyll A, and dissolved oxygen samples were also taken at the same sites on each river to ensure consistency. We found no significant difference between sites on the same river for the majority of our variables. There was, however, significance between the Maple River and the Carp Lake River in our variables tested. We found a significant difference in total Nitrogen levels between the two rivers and a significant difference from upstream and downstream at sites on each river, suggesting that the golf courses were sources of Nitrogen enrichment.http://deepblue.lib.umich.edu/bitstream/2027.42/64839/1/Bramble_Jones_Govus_2009.pd

    A point process framework for modeling electrical stimulation of the auditory nerve

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    Model-based studies of auditory nerve responses to electrical stimulation can provide insight into the functioning of cochlear implants. Ideally, these studies can identify limitations in sound processing strategies and lead to improved methods for providing sound information to cochlear implant users. To accomplish this, models must accurately describe auditory nerve spiking while avoiding excessive complexity that would preclude large-scale simulations of populations of auditory nerve fibers and obscure insight into the mechanisms that influence neural encoding of sound information. In this spirit, we develop a point process model of the auditory nerve that provides a compact and accurate description of neural responses to electric stimulation. Inspired by the framework of generalized linear models, the proposed model consists of a cascade of linear and nonlinear stages. We show how each of these stages can be associated with biophysical mechanisms and related to models of neuronal dynamics. Moreover, we derive a semi-analytical procedure that uniquely determines each parameter in the model on the basis of fundamental statistics from recordings of single fiber responses to electric stimulation, including threshold, relative spread, jitter, and chronaxie. The model also accounts for refractory and summation effects that influence the responses of auditory nerve fibers to high pulse rate stimulation. Throughout, we compare model predictions to published physiological data and explain differences in auditory nerve responses to high and low pulse rate stimulation. We close by performing an ideal observer analysis of simulated spike trains in response to sinusoidally amplitude modulated stimuli and find that carrier pulse rate does not affect modulation detection thresholds.Comment: 1 title page, 27 manuscript pages, 14 figures, 1 table, 1 appendi
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