3,409 research outputs found

    A Study on DNA Memory Encoding Architecture

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    The amount of raw generated data is growing at an exponential rate due to the greatly increasing number of sensors in electronic systems. While the majority of this data is never used, it is often kept for cases such as failure analysis. As such, archival memory storage, where data can be stored at an extremely high density at the cost of read latency, is becoming more popular than ever for long term storage. In biological organisms, Deoxyribonucleic Acid (DNA) is used as a method of storing information in terms of simple building blocks, as to allow for larger and more complicated struc- tures in a density much higher than can currently be realized on modern memory devices. Given the ability for organisms to store this information in a set of four bases for an extremely long amounts of time with limited degradation, DNA presents itself as a possible way to store data in a manner similar to binary data. This work investigates the use of DNA strands as a storage regime, where system-level data is translated into an efficient encoding to minimize base pair errors both at a local level and at the chain level. An encoding method using a Bose-Chaudhuri-Hocquenghem (BCH) pre-coded Raptor scheme is implemented in conjunction with an 8 to 6 bi- nary to base translation, yielding an informational density of 1.18 bits/base pair. A Field-Programmable Gate Array (FPGA) is then used in conjunction with a soft-core processor to verify address and key translation abilities, providing strong support that a strand-pool DNA model is reasonable for archival storage

    Development of a Handbook for Substitute Teachers in the East Irondequoit School District

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    All schools rely on substitute teachers to provide teaching coverage when full-time teachers experience sickness or personal issues. The purpose of this this study is to use the data in the creation of a “Substitute Teacher Handbook” for East Irondequoit School District to act as a reference for substitute teachers when facing the demands of their job. To accomplish this, the author created and administered a survey of 23 East Irondequoit substitute teachers. He found that 95% felt that a handbook of this nature would be helpful, while more than 80% expressed that substitute teachers should be able to keep the handbook as a ready personal reference. Substitutes suggested a number of topics for inclusion, including District Philosophy, salary schedules, drill and attendance policies, information about the student body, lists of administrative personnel, use of AV equipment, and a map of the school district. The researcher found that while the challenges faced by substitute teachers are very different from those faced by regular teachers, substitute teachers are still required to assume regular teachers’ roles for the duration of their stay. He noted the lack of written direction provided to substitutes, as well as substitutes’ perception that such direction is invaluable. Appendices include a draft of the information to be included in the handbook

    The McCall Glacier Project and Its Logistics

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    Describes the establishment and supply of two camps for this United States IGY micrometeorological and glacier-movement survey program, 1957-58. The McCall, an accessible valley glacier in the Romanzof Mts., eastern Brooks Range, northern Alaska, was chosen for the study during a reconnaissance flight in Aug. 1956. Transport was by air: prefabricated buildings, 34 tons of fuel and 18 tons of supplies and rations for the four-man party were parachuted from U.S. Air Force C-119 cargo planes during the 18-month program. Personnel, scientific instruments, and delicate apparatus were flown in by ski-equipped light planes; the glacier surface made an excellent landing field

    Aqueous-Based Extrusion Fabrication of Ceramics on Demand

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    Aqueous-Based Extrusion Fabrication is an additive manufacturing technique that extrudes ceramic slurries of high solids loading layer by layer for part fabrication. The material reservoir in a previously developed system has been modified to allow for starting and stopping of the extrusion process on demand. Design pros and cons are examined and a comparison between two material reservoir designs is made. Tests are conducted to determine the optimal deposition parameters for starting and stopping the extrudate on demand. The collected test data is used for the development of a deposition strategy that improves material deposition consistency, including reduced material buildup at sharp corners. Example parts are fabricated using the deposition strategy and hardware design.Mechanical Engineerin

    Development of Bone Targeting Drugs.

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    The skeletal system, comprising bones, ligaments, cartilage and their connective tissues, is critical for the structure and support of the body. Diseases that affect the skeletal system can be difficult to treat, mainly because of the avascular cartilage region. Targeting drugs to the site of action can not only increase efficacy but also reduce toxicity. Bone-targeting drugs are designed with either of two general targeting moieties, aimed at the entire skeletal system or a specific cell type. Most bone-targeting drugs utilize an affinity to hydroxyapatite, a major component of the bone matrix that includes a high concentration of positively-charged Ca(2+). The strategies for designing such targeting moieties can involve synthetic and/or biological components including negatively-charged amino acid peptides or bisphosphonates. Efficient delivery of bone-specific drugs provides significant impact in the treatment of skeletal related disorders including infectious diseases (osteoarthritis, osteomyelitis, etc.), osteoporosis, and metabolic skeletal dysplasia. Despite recent advances, however, both delivering the drug to its target without losing activity and avoiding adverse local effects remain a challenge. In this review, we investigate the current development of bone-targeting moieties, their efficacy and limitations, and discuss future directions for the development of these specific targeted treatments

    MRI: Acquisition of a SQUID Magnetometer for Analysis of Advanced Materials

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    Technical Summary: Superconducting quantum interference device (SQUID) magnetometry is a non-destructive technique that reveals detailed information about the electron spin interactions in many types of materials. This project will involve a state-of-the-art SQUID magnetometer and Magnetic Property Measurement System (MPMS), which is a critical tool for characterizing several types of materials currently being investigated by researchers within the Laboratory for Surface Science & Technology (LASST) and other University of Maine (UMaine) laboratories. Specific measurement capabilities include DC and AC magnetic susceptibility, magnetoresistivity, van der Paaw conductivity, and Hall mobility. State-of-the-art MPMS capabilities will be especially valuable to several research programs at UMaine pertaining to (i) surface magnetism in nanoparticles, (ii) magnetic anisotropies in sedimentary rocks, (iii) electrical transport in physical and chemical sensing devices, (iv) optical properties of nanostructures in high magnetic fields, and (v) magnetic nanoparticle based biosensors. The MPMS will serve as a focal point for training undergraduates, graduate students, postdocs, and visiting scientists in magnetic materials, nanotechnology, biophysics, and materials science. This instrument is a critical tool for expanding the capacity of UMaine research into magnetic aspects of nanotechnology, biophysics, sensor technology, and materials science. As no SQUID magnetometer currently exists in the State of Maine, the instrumentation will provide access for research projects from interested parties throughout the state, including non-Ph.D. granting institutions and small Maine businesses. The instrument is relatively easy to operate and provides direct information on electron spin interactions, and thus it will be a powerful tool to teach physics and nanotechnology concepts to several different constituents participating in UMaine outreach activities, including K-12 students and teachers, the general public, under-represented groups, and industry partners.Layman Summary: Superconducting quantum interference device (SQUID) magnetometry is a non-destructive technique that reveals detailed information about the electron spin interactions in many types of materials. Knowledge of electron interactions in materials is extremely important in building the next generation of computers, electronics, and contrast agents in biological magnetic screening techniques (i.e. MRI). To gain the necessary information, a system with control over both the magnetic field strength and temperature is critical. To this end, a SQUID/Magnetic Property Measurement System (MPMS) is ideal for these measurements. This project will purchase a state-of-the-art MPMS system and will be especially valuable to several research programs at UMaine pertaining to surface magnetism in nanoparticles, magnetic anisotropies in sedimentary rocks, electrical transport in physical and chemical sensing devices, and magnetic nanoparticle based biosensors. The proposed MPMS will serve as a focal point for training undergraduates, graduate students, postdocs, and visiting scientists in magnetic materials, nanotechnology, biophysics, and materials science. As no SQUID magnetometer currently exists in the State of Maine, the instrumentation will provide access for research projects from interested parties throughout the state, including non-Ph.D. granting institutions and small Maine businesses. The instrument is relatively easy to operate and provides direct information on electron spin interactions, and thus it will be a powerful tool to teach physics and nanotechnology concepts to several different constituents participating in UMaine outreach activities, including K-12 students and teachers, the general public, under-represented groups, and industry partners

    Transient Heavy Element Absorption Systems in Novae: Episodic Mass Ejection from the Secondary Star

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    A high-resolution spectroscopic survey of postoutburst novae reveals short-lived heavy element absorption systems in a majority of novae near maximum light, having expansion velocities of 400-1000 km/s and velocity dispersions between 35-350 km/s. A majority of systems are accelerated outwardly, and they all progressively weaken and disappear over timescales of weeks. A few of the systems having narrow, deeper absorption reveal a rich spectrum of singly ionized Sc, Ti, V, Cr, Fe, Sr, Y, Zr, and Ba lines. Analysis of the richest such system, in Nova LMC 2005, shows the excitation temperature to be 104 K and elements lighter than Fe to have abundance enhancements over solar values by up to an order of magnitude. The gas causing the absorption systems must be circumbinary and its origin is most likely mass ejection from the secondary star. The absorbing gas pre-exists the outburst and may represent episodic mass transfer events from the secondary star that initiate the nova outburst(s). If SNe Ia originate in single degenerate binaries, such absorption systems could be detectable before maximum lightComment: 19 pages, 6 figures, accepted for publication in the Astrophysical Journa
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