756 research outputs found

    Harmonic maps from the tangent bundle

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    Integrating certifications into the cybersecurity college curriculum: The efficacy of education with certifications to increase the cybersecurity workforce

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    One only needs to listen to the news reports to recognize that the gap between securing the enterprise and cybersecurity threats, breaches, and vulnerabilities appears to be widening at an alarming rate. An un-tapped resource to combat these attacks lies in the students of the secondary educational system. Necessary in the cybersecurity education is a 3-tiered approach to quickly escalate the student into a workplace-ready graduate. The analogy used is a three-legged-stool, where curriculum content, hands-on skills, and certifications are equal instruments in the edification of the cybersecurity student. This paper endeavors to delve into the 3rd leg of the stool by developing the concept of vendor-specific and vendor-neutral certifications to educate the cybersecurity student and test their capability of protecting the workplace. The research data was drawn from companies in the Atlanta, Georgia area, who employ and hire cybersecurity recruits. The data from the research proves certifications are necessary as an addition to the cybersecurity curriculum in the secondary education arena. The paper reviews the need for cybersecurity graduates, the balance between cybersecurity theory and applied skillsets, the difference between a certificate and a certification, benefits to the community, classifications of certifications, relevancy of a college degree in today’s workforce, and recommendations for further study

    A spatially and temporally localized sub-laser-cycle electron source

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    We present an experimental and numerical study of electron emission from a sharp tungsten tip triggered by sub-8 femtosecond low power laser pulses. This process is non-linear in the laser electric field, and the non-linearity can be tuned via the DC voltage applied to the tip. Numerical simulations of this system show that electron emission takes place within less than one optical period of the exciting laser pulse, so that an 8 fsec 800 nm laser pulse is capable of producing a single electron pulse of less than 1 fsec duration. Furthermore, we find that the carrier-envelope phase dependence of the emission process is smaller than 0.1% for an 8 fsec pulse but is steeply increasing with decreasing laser pulse duration.Comment: 4 pages, 5 figure

    Europium nitride: A novel diluted magnetic semiconductor

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    Europium nitride is semiconducting and contains non-magnetic \3+, but sub-stoichiometric EuN has Eu in a mix of 2+ and 3+ charge states. We show that at \2+ ~concentrations near 15-20% EuN is ferromagnetic with a Curie temperature as high as 120 K. The \3+ ~polarization follows that of the \2+, confirming that the ferromagnetism is intrinsic to the EuN which is thus a novel diluted magnetic semiconductor. Transport measurements shed light on the likely exchange mechanisms.Comment: 5 page

    Recovery of Small DNA Fragments from Serum Using Compaction Precipitation

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    Background: While most nucleic acids are intracellular, trace amounts of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), including micro RNAs, can also be found in peripheral blood. Many studies have suggested the potential utility of these circulating nucleic acids in prenatal diagnosis, early cancer detection, and the diagnosis of infectious diseases. However, DNA circulating in blood is usually present at very low concentrations (ng/ml), and is in the form of relatively small fragments (,1,000 bp), making its isolation challenging. Methods: Here we report an improved method for the isolation of small DNA fragments from serum using selective precipitation by quaternary ammonium compaction agents. A 151 bp fragment of double-stranded DNA from the Escherichia coli bacteriophage lambda served as the model DNA in our experiments. DNA was serially diluted in serum until undetectable by conventional polymerase chain reaction (PCR), before being enriched by compaction precipitation. Results: Starting with concentrations two to three orders of magnitude lower than the PCR-detectable level (0.01 ng/ml), we were able to enrich the DNA to a detectable level using a novel compaction precipitation protocol. The isolated DNA product after compaction precipitation was largely free of serum contaminants and was suitable for downstream applications. Conclusions: Using compaction precipitation, we were able to isolate and concentrate small DNA from serum, and increase the sensitivity of detection by more than four orders of magnitude. We were able to recover and detect very low levels (0.01 ng/ml) of a small DNA fragment in serum. In addition to being very sensitive, the method is fast, simple, inexpensive, and avoids the use of toxic chemicals

    Increasing Binding Efficiency via Reporter Shape and Flux in a Viral Nanoparticle Lateral-Flow Assay

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    To identify factors controlling the performance of reporter particles in a sensitive lateral-flow assay (LFA), we investigated the effect of the flux and shape of filamentous bacteriophage (phage) on the performance of phage LFAs. Phage of three different lengths and diameters were modified with biotin and AlexaFluor 555 as binding and read-out elements, respectively. The binding efficiencies of the functionalized phage were tested in a fibrous glass LFA membrane modified with avidin. The total binding rate, quantified using real-time particle counting and particle image velocimetry, decreased monotonically with the average bulk flux of phage through the membrane. At the pore scale, more phage bound in regions with faster local flow, confirming that both average and local flux increased binding. The number of bound phage increased with the aspect ratio of the phage and scaled with the phage surface area, consistent with a binding interaction controlled by the number of recognition elements on the surface. Together, these results indicate that increasing the likelihood that recognition elements on the surface of phage encounter the fibers enhances the assay binding efficiency and suggests one origin for the improved performance of nonspherical phage reporters

    Rationale and practical techniques for mouse models of early vein graft adaptations

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    Mouse models serve as relatively new yet powerful research tools to study intimal hyperplasia and wall remodeling of vein bypass graft failure. Several model variations have been reported in the past decade. However, the approach demands thoughtful preparation, selected sophisticated equipment, microsurgical technical expertise, advanced tissue processing, and data acquisition. This review compares several described models and aims (building on our personal experiences) to practically aid the investigators who want to utilize mouse models of vein graft failure.Clinical RelevanceSurgical revascularization via vein grafting offers immediate and often dramatic end organ benefit. However, substantial percentages of vein conduits placed develop stenosis or fail, often early. Mechanistic studies of the complex interplay between the biologic and physical forces that drive failure have been hampered by limited quantity and quality of clinical specimens, and the inability of systems such as computer models and cell culture to mimic the clinical circumstance. This review summarizes the power and limitations of mouse vein graft models, and it includes practical experience-based advice for researchers aiming to utilize this tool

    Superpixel-based segmentation of muscle fibers in multi-channel microscopy

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    Background Confetti fluorescence and other multi-color genetic labelling strategies are useful for observing stem cell regeneration and for other problems of cell lineage tracing. One difficulty of such strategies is segmenting the cell boundaries, which is a very different problem from segmenting color images from the real world. This paper addresses the difficulties and presents a superpixel-based framework for segmentation of regenerated muscle fibers in mice. Results We propose to integrate an edge detector into a superpixel algorithm and customize the method for multi-channel images. The enhanced superpixel method outperforms the original and another advanced superpixel algorithm in terms of both boundary recall and under-segmentation error. Our framework was applied to cross-section and lateral section images of regenerated muscle fibers from confetti-fluorescent mice. Compared with “ground-truth” segmentations, our framework yielded median Dice similarity coefficients of 0.92 and higher. Conclusion Our segmentation framework is flexible and provides very good segmentations of multi-color muscle fibers. We anticipate our methods will be useful for segmenting a variety of tissues in confetti fluorecent mice and in mice with similar multi-color labels.National University of Singapore (Duke-NUS SRP Phase 2 Research Block Grant)Singapore. National Research Foundation (CREATE programme)Singapore-MIT Alliance for Research and Technology (SMART

    Forage Grasses and Legumes with Broad Adaptation for Southeast Asia

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    A wide range of forages is currently being evaluated by farmers and researchers in seven countries in Southeast Asia. Broadly-adapted species have been identified for fodder banks, grazed systems, tree cropping, erosion control and improved fallows. The most promising accessions to date are Stylosanthes guianensis CIAT 184, Brachiaria decumbens cv Basilisk, Brachiaria humidicola cv Tully and CIAT 6133, CIAT 6780, Centrosema pubescens CIAT 15160 and Andropogon gayanus cv Kent and CIAT 621. Other forages that show promise are Paspalum atratum, Arachis pintoi, and Macroptilium gracile cv. Maldonado. Local seed supply and distribution systems are needed to ensure that these species reach their potential on farms

    Electronic Payment Systems: Payment Gateways and Data Security Standards

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    The use of smartphones, tablets, and laptops allow electronic transactions to be made anytime, anywhere, and by anyone. This version of commerce, known as e-commerce or digital commerce, has become a mainstay in the way consumers shop. Online payments have essentially made cash payment systems virtually obsolete. Also, the Internet has made it possible for businesses to expand their reach across the globe. More importantly, due to the proliferation of social media as a guiding agent for purchasing decisions, e-commerce has evolved into one of the most significant driving forces into how businesses generate revenue (Wong 2018). According to the U.S. Census Bureau (2019), the year’s retail e-commerce sales reached 154.7 billion, and the data indicated that sales would continue to grow. Coexisting with the steady rise of sales is the need for skilled and knowledgeable workers. Torpey (2018) shared a Bureau of Labor and Statistics report which revealed that e-commerce employment is expected to reach approximately 450,000 by 2026. Many of these jobs require advanced knowledge of credit card standards and acceptance procedures. Aligned to these expectations, the purpose of this project was to garner an understanding of payment gateways (PGs) and Payment Card Industry Data Security Standards (PCI-DSS) to develop material to enhance an undergraduate e-commerce curriculum. The outcome of this research will be three-fold. First, it will offer qualitative outcomes on how students and teachers collaborated on gathering appropriate learning material to be used in the classroom. Second, the results of a quantitative student survey, administered near the end of the semester, will provide supporting evidence of the need to add this material into the curriculum. Third, using a scholarly practitioner model, the outcomes will bridge the gap between academia and real-world applications to equip students with the necessary knowledge to enter the workforce
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