5,172 research outputs found

    Spatially selecting single cell for lysis using light induced electric fields

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    An optoelectronic tweezing (OET) device, within an integrated microfluidic channel, is used to precisely select single cells for lysis among dense populations. Cells to be lysed are exposed to higher electrical fields than their neighbours by illuminating a photoconductive film underneath them. Using beam spot sizes as low as 2.5 μm, 100% lysis efficiency is reached in <1 min allowing the targeted lysis of cells

    Implications of Polarized Pupil Degradation Due to Focal Shifts in Dynamically Ranged Rayleigh Beacons

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    A dynamically ranged pulsed Rayleigh beacon using sensed wavefronts across a system’s pupil plane is proposed for tomographic quantification of the atmospheric turbulence strength. This method relies on relaying light from a telescope system’s pupil plane to a wavefront sensor and having precise control of the light-blocking mechanisms to filter out scattered light from the unwanted scattering regions along the propagation path. To accomplish this, we tested and incorporated design features into the sensing system that we believe, to the best of our knowledge, are unique. Dynamically changing the range of the beacon source created focal shifts along the optical axis in the telescope sensing system. This effect induced polarization degradation in the optical pupil. As a result, polarization nonuniformity within the Pockels cell resulted in light leakages that corrupted the sensed data signals. To mitigate this unwanted effect, an analysis of the polarization pupil had to be completed for the range of possible Rayleigh beacon source distances, relating the change in polarization to the ability of a Pockels cell to function as an optical shutter. Based on the resultant polarization pupil analysis, careful design of the light relay architecture of the sensing system was necessary to properly capture sensed wavefront data from a series of intended ranges. Results are presented for the engineering design of the Turbulence and Aerosol Research Dynamic Interrogation System sensing system showing the choices made within the trade space and how those choices were made based on an analysis of the polarization pupil. Based on what we learned, recommendations are made to effectively implement a polarization-based Pockels cell shutter system as part of a dynamically ranged Rayleigh beacon system

    Secondary Legal Sources: A Selected Subject Bibliography of Treatises, Looseleaf Services and Form Books Fourth Edition

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    The fourth edition of this bibliography is a subject arrangement of selected English language treatises, looseleaf services and form books. Most all of the works listed were published in this country and all are in the collection of this law library. Our object in revising this bibliography has been to present to the law students of The University of Michigan a reasonably thorough listing of useful and current secondary sources covering dorr1estic and international Jaw. The inclusion of a work in this bibliography does not mean that the Law Library is endorsing either the author\u27s style or the substance of his work. It does mean that we believe the work to be useful in the research of our patrons. While this bibliography is by no means exhaustive in its coverage of secondary sources on any subject, it does identify most of the major works in a given area. Thus, it can best be used as a starting point for legal research. It is not, however, a substitute for the card catalog which must be consulted during any serious research effort. In selecting titles for inclusion in the bibliography and in removing titles that had been in the third Edition, we have been guided by a consideration of the currency of the material. The materials listed deal with the law in its current state. Other than indirectly, this bibliography is not designed to support retrospective research. We have indicated by use of the term current those treatises which have been kept up to date by some sort of supplementation. Obviously, depending upon the subject, texts become dated at widely different intervals. Therefore, in including or deleting titles, we have looked to changes in the law, as well as to the date of publication. We have made only one major \u27\u27structural change in this edition of the bibliography. We have taken the former subject headings civil procedure and practice and procedure and combined them in a new heading civil practice and procedure . We think that this will make it easier to find the full range of material on this subject. A final word on the content of the bibliography is in order. As in past editions, we have attempted to exclude works which are more polemical than expository. We have also excluded casebooks and popular works on the law which, while possibly helpful to laymen, would be of limited use to the law student. We have, again, not included books concerned with law reform, criticism of legal institutions or the social science aspects of law, except for those dealing with the sociology of law. Nor have we included works dealing with the law of\u27 a single region or state. Finally, we have not included reference works, such as general form books and encyclopedias, which cover a vast expanse of legal knowledge. On the other hand, listed books that deal with more than one subject are placed under all appropriate subject headings This bibliography is current as of July 1, 1980. Finally, much thanks is due to Phyllis Rosenstock for her patience, endurance, skill and good humor in typing this bibliography

    Matching times of leading and following suggest cooperation through direct reciprocity during V-formation flight in ibis

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    One conspicuous feature of several larger bird species is their annual migration in V-shaped or echelon formation. When birds are flying in these formations, energy savings can be achieved by using the aerodynamic up-wash produced by the preceding bird. As the leading bird in a formation cannot profit from this up-wash, a social dilemma arises around the question of who is going to fly in front? To investigate how this dilemma is solved, we studied the flight behavior of a flock of juvenile Northern bald ibis (Geronticus eremita) during a human-guided autumn migration. We could show that the amount of time a bird is leading a formation is strongly correlated with the time it can itself profit from flying in the wake of another bird. On the dyadic level, birds match the time they spend in the wake of each other by frequent pairwise switches of the leading position. Taken together, these results suggest that bald ibis cooperate by directly taking turns in leading a formation. On the proximate level, we propose that it is mainly the high number of iterations and the immediacy of reciprocation opportunities that favor direct reciprocation. Finally, we found evidence that the animals' propensity to reciprocate in leading has a substantial influence on the size and cohesion of the flight formations

    RF Replay System for Narrowband GNSS IF Signals

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    Richard Nelson Perham. 27 April 1937—14 February 2015

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    Richard Nelson Perham, FRS, FMedSci, FRSA, was a British professor of structural biochemistry. He undertook his academic career at the University of Cambridge, holding positions as lecturer, reader, chair and head of the Department of Biochemistry, as well as becoming Master of St John's College. Perham published close to 300 scientific papers on protein structure and function, with a focus on mechanistic enzymology, particularly how large multienzyme complexes and flavin-containing enzymes work. He is most renowned for determining how reactive intermediates are transferred between enzyme active sites, for alterations of coenzyme and substrate specificity by his pioneering use of protein engineering and for developing protein display methodologies. Married to Nancy Lane-Perham, and with their two children, Perham enjoyed a full and active life in Cambridge and St John's College. He was a keen participator and supporter of sport and enjoyed art, literature, theatre and music. Perham was a vocal and active champion of equal opportunity in education. His legacy to science is a greater understanding of how enzymes work. His legacy to scientists is as a role model of how to attain the highest levels of achievement while maintaining a sense of personal modesty and a keen support for others

    Image Quality vs. NEC in 2D and 3D PET

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    To investigate the relationship between NEC and image quality to 2D and 3D PET, while simultaneously optimizing 3D low energy threshold (LET), we have performed a series of phantom measurements. The phantom consisted of 46 1 cm fillable hollow spheres on a random grid inside a water-filled oval cylinder, 21 cm tall, 36 cm wide, and 40 cm long. The phantom was imaged on a Discovery ST PET/CT system (GE Healthcare, Milwaukee, WI) in a series of 3 min scans as it decayed from an activity of 7.2 mCi. The scans included LET settings of 375,400, and 425 keV in 3D, and 375 keV in 2D. Image signal-to-noise (SNR) was calculated and compared wash NEC. While both NEC and image quality in 3D improved for LETs above the default of 375 keV, we found that there were significant differences between NEC and image quality for 2D and 3D. Most importantly, 3D image-quality was strongly dependent on the reconstruction algorithm and its associated parameters. In conclusion, a direct measure of image quality as necessary for comparing 2D vs. 3D performance

    A Systems Approach and Notional Response Model for Preserving the Health System during the COVID-19 Pandemic

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    During any pandemic, it has long been known that local jurisdictions would need to be self-sufficient with little or no outside assistance, particularly from the federal government. While all eyes have been on California, New York, and Massachusetts, the capacities of health systems in other states have yet to be put to the test. If there are subsequent waves of COVID-19 and other jurisdictions see significant increases in disease spread, the systems used to respond will become critical.Using a review and synthesis approach, this article explores our collective experience and knowledge as it pertains to use of alternate care sites for dealing with the patient surge created by a disease outbreak. Probing the concept of alternate care site (ACS) systems reveals various types of alternate care sites that may be employed during an outbreak. The historical value of ACS models used during outbreak response are discussed. This culminates in the development of a notional response model and list of actions that should be taken by all jurisdictions as we prepare for additional waves of disease
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