5,745 research outputs found

    "Security Model for a Central Bank in Latin America using Blockchain"

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    "Banking institutions in Latin America are the target of increasingly sophisticated and advanced cyber-attacks and threats, which increase every year and leave substantial economic losses, due to the high level of global interconnection and digitization of their operations. The objective of this work is to design a model to guarantee information security in a Central Bank in Latin America using Blockchain technology. Exploratory research, observation and inductive and deductive methods are used to propose Blockchain solutions in a Central Bank. The results are a model for secure transactions in Blockchain, Smart Contract functions and a data management process. It was concluded that the security model for a central bank provides high level of information management and storage of transactions in a secure and immutable way.

    A Proposed Astronomy Learning Progression For Remote Telescope Observation

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    Providing meaningful telescope observing experiences for students who are deeply urban or distantly rural place-bound—or even daylight time-bound—has consistently presented a formidable challenge for astronomy educators.  For nearly 2 decades, the Internet has promised unfettered access for large numbers of students to conduct remote telescope observing, but it has only been in recent years that the technology has become readily available.  Now that this once fanciful possibility is becoming a reality, astronomy education researchers need a guiding theory on which to develop learning experiences.  As one departure point, we propose a potential learning progression anchored on one end with recognizing that stars visible at night have describable locations and predictable motions, and anchored at the other with distant robotic telescopes can be programmed to record specific astronomical data for later analysis

    Performance Analysis of ML-based MTC Traffic Pattern Predictors

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    Prolonging the lifetime of massive machine-type communication (MTC) networks is key to realizing a sustainable digitized society. Great energy savings can be achieved by accurately predicting MTC traffic followed by properly designed resource allocation mechanisms. However, selecting the proper MTC traffic predictor is not straightforward and depends on accuracy/complexity trade-offs and the specific MTC applications and network characteristics. Remarkably, the related state-of-the-art literature still lacks such debates. Herein, we assess the performance of several machine learning (ML) methods to predict Poisson and quasi-periodic MTC traffic in terms of accuracy and computational cost. Results show that the temporal convolutional network (TCN) outperforms the long-short term memory (LSTM), the gated recurrent units (GRU), and the recurrent neural network (RNN), in that order. For Poisson traffic, the accuracy gap between the predictors is larger than under quasi-periodic traffic. Finally, we show that running a TCN predictor is around three times more costly than other methods, while the training/inference time is the greatest/least.Comment: IEEE Wireless Communications Letters Print ISSN: 2162-2337 Online ISSN: 2162-234

    Microscopic-observation drug-susceptibility assay for the diagnosis of TB.

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    BACKGROUND: New diagnostic tools are urgently needed to interrupt the transmission of tuberculosis and multidrug-resistant tuberculosis. Rapid, sensitive detection of tuberculosis and multidrug-resistant tuberculosis in sputum has been demonstrated in proof-of-principle studies of the microscopic-observation drug-susceptibility (MODS) assay, in which broth cultures are examined microscopically to detect characteristic growth. METHODS: In an operational setting in Peru, we investigated the performance of the MODS assay for culture and drug-susceptibility testing in three target groups: unselected patients with suspected tuberculosis, prescreened patients at high risk for tuberculosis or multidrug-resistant tuberculosis, and unselected hospitalized patients infected with the human immunodeficiency virus. We compared the MODS assay head-to-head with two reference methods: automated mycobacterial culture and culture on Löwenstein-Jensen medium with the proportion method. RESULTS: Of 3760 sputum samples, 401 (10.7%) yielded cultures positive for Mycobacterium tuberculosis. Sensitivity of detection was 97.8% for MODS culture, 89.0% for automated mycobacterial culture, and 84.0% for Löwenstein-Jensen culture (P<0.001); the median time to culture positivity was 7 days, 13 days, and 26 days, respectively (P<0.001), and the median time to the results of susceptibility tests was 7 days, 22 days, and 68 days, respectively. The incremental benefit of a second MODS culture was minimal, particularly in patients at high risk for tuberculosis or multidrug-resistant tuberculosis. Agreement between MODS and the reference standard for susceptibility was 100% for rifampin, 97% for isoniazid, 99% for rifampin and isoniazid (combined results for multidrug resistance), 95% for ethambutol, and 92% for streptomycin (kappa values, 1.0, 0.89, 0.93, 0.71, and 0.72, respectively). CONCLUSIONS: A single MODS culture of a sputum sample offers more rapid and sensitive detection of tuberculosis and multidrug-resistant tuberculosis than the existing gold-standard methods used

    Eliminating Amylase Testing from the Evaluation of Pancreatitis in the Emergency Department

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    Background: Alterations in serum biomarkers have been used to evaluate for pancreatitis in the emergency department (ED). Studies have shown lipase to be as sensitive and more specific than amylase in diagnosing pancreatitis and that amylase plus lipase does not improve accuracy over lipase alone.Objective: To determine effects of interventions to decrease ordering of amylase in the evaluation of pancreatitis.Methods: We conducted a pre- and post-cohort study. The number of amylase and lipase tests ordered in the ED was recorded prior to intervention to establish a baseline. We introduced an educational intervention to order lipase without amylase. A second intervention involved removing amylase from bedside order entry forms. We introduced a third intervention that included deleting amylase from trauma order forms, and decoupling amylase and lipase in the computer ordering system. We recorded the number of lipase and amylase tests in weekly aggregates for comparison to the baseline. Data analysis using students t-test, standard deviation and p values are reported.Results: Before interventions 93% of patients had both tests ordered. Educational interventions resulted in a decrease to 91% (p=0.06) of co-ordering. Further interventions decreased the percentage of patients evaluated with both tests to 14.3%. This translates into a decrease in patient charges of approximately $350,000 a year.Conclusion: Using simple structured interventions in the ED can reduce amylase ordering. Educational programming alone was not effective in significantly decreasing amylase ordering; however, education plus system-based interventions decreased amylase ordering. [West J Emerg Med. 2010; 11(4):344-347.

    Immunolocalization and temporal distribution of cytokine expression during the development of vein graft intimal hyperplasia in an experimental model

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    AbstractPurpose: Vein graft stenosis caused by intimal hyperplasia (IH) accounts for 30% to 50% of late bypass graft failures; however, the biochemical mediators of vein graft IH have been poorly defined. We attempted to evaluate the spatial and temporal distribution of five principal cytokines (interleukin-1 beta [IL-1β], platelet-derived growth factor AA [PDGF-AA], basic fibroblast growth factor [bFGF], interferon gamma [INFγ], and tumor necrosis factor alpha [TNF-α]) during the development of IH in a rat vein graft model.Methods: Rat epigastric vein interposition grafts in the femoral artery were harvested at 6 hours, 2 days, 1 week, 2 weeks, and 4 weeks after the grafting procedure and studied with immunohistochemical and standard histologic techniques. The cytokine expression in the endothelium and media/neointima was quantified as the percentage of immunopositive cells per high-power field.Results: Maximal hyperplasia occurred 2 weeks after the grafting procedure. Peak expression of IL-1β and bFGF occurred by 2 days. PDGF-AA expression paralleled the development of IH, peaking at 2 weeks and then declining. TNF-α expression increased at 1 week and remained elevated. INFγ was seen only in control grafts.Conclusions: The coordinated early release of IL-1β and bFGF and the down-regulation of INFγ seem to trigger an inflammatory response, thereby initiating IH. The process then is propagated by the release of PDGF-AA and TNF-α, with concomitant smooth muscle cell proliferation and production of extracellular matrix. It is likely that this complex milieu of local paracrine signaling is required to generate the hyperplastic response seen in failing vein grafts. (J Vasc Surg 1996;24:463-71.

    Brillouin scattering study on the single-crystal elastic properties of natrolite and analcime zeolites

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    Copyright © 2005 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics 98 (2005) and may be found at http://link.aip.org/link/?jap/98/053508The Brillouin light-scattering technique was used to investigate the single-crystal elastic properties of two aluminosilicate zeolites, natrolite (NAT) and analcime (ANA), at ambient conditions. An inversion of the acoustic velocity data results in the full set of elastic stiffness moduli (Cij's) for both materials. From the single-crystal moduli the aggregate adiabatic bulk moduli (Ks), shear moduli (G), and Poisson's ratios (v) were found to be Ks=48.5(1.0) GPa, G=31.6(1.0) GPa, and v =0.232(5) for NAT, and Ks=59.8(1.2) GPa, G=32.1(1.0) GPa, and v=0.272(5) for ANA (Voigt-Reuss-Hill averages). The bulk and shear moduli of both zeolites are relatively low compared with those of densely packed aluminosilicates, reflecting an open framework structure of (Al,SiO4) tetrahedra which is easily deformed by bending the Si–O–Al angles. As expected for a less dense crystal, NAT is softer and more compressible than ANA. An evaluation of the directional Young's moduli shows that the compressibility of NAT is nearly uniform along the [100] and [010] axes, while [001] is stiffer, in agreement with previous compression studies. We do not find experimental evidence of negative Poisson's ratios for NAT zeolites as predicted by recent theoretical calculations

    Herd-level animal management factors associated with the occurrence of bovine neonatal pancytopenia in calves in a multicountry study

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    Since 2007, mortality associated with a previously unreported haemorrhagic disease has been observed in young calves in several European countries. The syndrome, which has been named ‘bovine neonatal pancytopenia’ (BNP), is characterised by thrombocytopenia, leukocytopenia and a panmyelophthisis. A herd-level case-control study was conducted in four BNP affected countries (Belgium, France, Germany and the Netherlands) to identify herd management risk factors for BNP occurrence. Data were collected using structured face-to-face and telephone interviews of farm managers and their local veterinarians. In total, 363 case farms and 887 control farms were included in a matched multivariable conditional logistic regression analysis. Case-control status was strongly associated with the odds of herd level use of the vaccine PregSure® BVD (PregSure, Pfizer Animal Health) (matched adjusted odds ratio (OR) 107.2; 95% CI: 41.0–280.1). This was also the case for the practices of feeding calves colostrum from the calf’s own dam (OR 2.0; 95% CI: 1.1–3.4) or feeding pooled colostrum (OR 4.1; 95% CI: 1.9–8.8). Given that the study had relatively high statistical power and represented a variety of cattle production and husbandry systems, it can be concluded with some confidence that no other herd level management factors are competent causes for a sufficient cause of BNP occurrence on herd level. It is suggested that genetic characteristics of the dams and BNP calves should be the focus of further investigations aimed at identifying the currently missing component causes that together with PregSure vaccination and colostrum feeding represent a sufficient cause for occurrence of BNP in calves

    Managing soil carbon and nitrogen for productivity and environmental quality

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    Includes bibliographical references (pages 774-775).In this study, we investigated the impact of cropping system management on C and N pools, crop yield, and N leaching in a long-term agronomic experiment in Southwest Michigan. Four management types, conventional (CO), integrated fertilizer (IF), integrated compost (IC), and transitional organic (TO) were applied to two crop sequences, a corn (Zea mays L.)–corn–soybean [Glycine max (L.) Merr.]–wheat (Triticum aestivum L.) rotation and continuous corn, which were grown with and without cover crops in the IF, IC, and TO managements. Using compost as a fertility source and reducing the use of herbicides and other chemicals resulted in long-term changes in soil organic matter pools such TO ≥ IC > IF ≥ CO for total C and N and for the labile C and N measured through aerobic incubations at 70 and 150 d. Mineralizable N varied within the rotation, tending to increase after soybean and decrease after corn production in all systems. Corn yield was closely associated with 70-d N mineralization potential, being greatest for first-year corn with cover and least for continuous corn without cover under all management types. Although the TO and IC systems produced the lowest yield for second-year or continuous corn, the combination of soybean and wheat plus red clover (Trifolium pratense L.) always supported high yield for first-year corn. Fall nitrate level and nitrate leaching were higher for commercially fertilized corn than for any other crop or for compost-amended corn

    The impact of methodology on the reproducibility and rigor of DNA methylation data

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    Epigenetic modifications are crucial for normal development and implicated in disease pathogenesis. While epigenetics continues to be a burgeoning research area in neuroscience, unaddressed issues related to data reproducibility across laboratories remain. Separating meaningful experimental changes from background variability is a challenge in epigenomic studies. Here we show that seemingly minor experimental variations, even under normal baseline conditions, can have a significant impact on epigenome outcome measures and data interpretation. We examined genome-wide DNA methylation and gene expression profiles of hippocampal tissues from wild-type rats housed in three independent laboratories using nearly identical conditions. Reduced-representation bisulfite sequencing and RNA-seq respectively identified 3852 differentially methylated and 1075 differentially expressed genes between laboratories, even in the absence of experimental intervention. Difficult-to-match factors such as animal vendors and a subset of husbandry and tissue extraction procedures produced quantifiable variations between wild-type animals across the three laboratories. Our study demonstrates that seemingly minor experimental variations, even under normal baseline conditions, can have a significant impact on epigenome outcome measures and data interpretation. This is particularly meaningful for neurological studies in animal models, in which baseline parameters between experimental groups are difficult to control. To enhance scientific rigor, we conclude that strict adherence to protocols is necessary for the execution and interpretation of epigenetic studies and that protocol-sensitive epigenetic changes, amongst naive animals, may confound experimental results
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