774 research outputs found

    Letter to Sonora Dodd from Edwin Johnson, June 10, 1935

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    Letter to Sonora Dodd from Edwin Johnson, with envelope. Edwin C. Johnson served as Governor of the State of Colorado from 1933 to 1937, as U.S. Senator from Colorado from 1937 to 1955, and then again as Governor of Colorado from 1955 to 1957.https://digitalcommons.whitworth.edu/fathers-day-correspondence/1048/thumbnail.jp

    Autonomous Flight in Unknown Indoor Environments

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    http://multi-science.metapress.com/content/80586kml376k2711/This paper presents our solution for enabling a quadrotor helicopter, equipped with a laser rangefinder sensor, to autonomously explore and map unstructured and unknown indoor environments. While these capabilities are already commodities on ground vehicles, air vehicles seeking the same performance face unique challenges. In this paper, we describe the difficulties in achieving fully autonomous helicopter flight, highlighting the differences between ground and helicopter robots that make it difficult to use algorithms that have been developed for ground robots. We then provide an overview of our solution to the key problems, including a multilevel sensing and control hierarchy, a high-speed laser scan-matching algorithm, an EKF for data fusion, a high-level SLAM implementation, and an exploration planner. Finally, we show experimental results demonstrating the helicopter's ability to navigate accurately and autonomously in unknown environments.National Science Foundation (U.S.) (NSF Division of Information and Intelligent Systems under grant # 0546467)United States. Army Research Office (ARO MAST CTA)Singapore. Armed Force

    An Analysis of Fifty Delinquent Boys\u27 Feelings of Inferiority and Superiority

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    By the use of tests a group of boys showing decided inclinations toward feelings of superiority or inferiority was selected from the Iowa Boys Training School at Eldora. The members of this group were interviewed, and the boys\u27 own stories obtained. Comparisons were made with the judgments of the teachers and the case records. An analysis of the resulting pictures suggests definite lines for further investigation

    Eliminating Fruit and Vegetable Planting Restrictions: How Would Markets Be Affected?

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    Eighty-nine percent of American households were food secure throughout the entire year in 2005, meaning that they had access, at all times, to enough food for an active, healthy life for all household members. The remaining households were food insecure at least some time during that year. The prevalence of food insecurity declined from 11.9 percent of households in 2004 to 11.0 percent in 2005, while the prevalence of very low food security remained unchanged at 3.9 percent. This report, based on data from the December 2005 food security survey, provides the most recent statistics on the food security of U.S. households, as well as on how much they spent for food and the extent to which food-insecure households participated in Federal and community food assistance programs. Survey responses indicate that the typical food-secure household in the U.S. spent 34 percent more on food than the typical food-insecure household of the same size and household composition. Just over one-half of all food-insecure households participated in one or more of the three largest Federal food assistance programs during the month prior to the survey. About 22 percent of food-insecure households—3.5 percent of all U.S. households—obtained emergency food from a food pantry at some time during the year.Food security, food insecurity, food spending, food pantry, hunger, soup kitchen, emergency kitchen, material well-being, Food Stamp Program, National School, Crop Production/Industries,

    Reluctant glass formers and their applications in optical lens design

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    Over ten years ago, it was shown that glasses with high index of refraction and some with low dispersion could be produced from a number of pure refractory oxides, including the lanthanides, by containerless processing. By containerless processing it is possible to minimize surface heterogeneous nucleation and produce larger glass samples of the materials than by other methods. The use of proposed high temperature containerless processing facilities in space permits the fabrication of benchmark samples of new unique glass compositions for optical property determination as well as for glass formation. It was shown that glasses with high refractive indices and large Abbe numbers can be formulated using this technology. These glasses lie in the classical forbidden region of the glass map. Preliminary study of the impact of having such unusual glasses available for the lens designer was made. Results indicate that significant improvements can be realized over the use of only conventional glasses. A cursory survey of a number of nationally recognized lens designers indicated a general agreement that such glasses would be highly desired and could be expected to lead to completely new designs as well as simplifying existing designs

    Synaptotagmins I and II mediate entry of botulinum neurotoxin B into cells

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    Botulinum neurotoxins (BoNTs) cause botulism by entering neurons and cleaving proteins that mediate neurotransmitter release; disruption of exocytosis results in paralysis and death. The receptors for BoNTs are thought to be composed of both proteins and gangliosides; however, protein components that mediate toxin entry have not been identified. Using gain-of-function and loss-of-function approaches, we report here that the secretory vesicle proteins, synaptotagmins (syts) I and II, mediate the entry of BoNT/B (but not BoNT/A or E) into PC12 cells. Further, we demonstrate that BoNT/B entry into PC12 cells and rat diaphragm motor nerve terminals was activity dependent and can be blocked using fragments of syt II that contain the BoNT/B-binding domain. Finally, we show that syt II fragments, in conjunction with gangliosides, neutralized BoNT/B in intact mice. These findings establish that syts I and II can function as protein receptors for BoNT/B

    Effect of surfactants on the thermoresponse of PNIPAM investigated in the brush geometry

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    Hypothesis: Anionic surfactants have been reported to interact with poly(N-isopropyl acrylamide) (PNIPAM), suppressing its thermoresponse. Scattering and NMR studies of the anionic sodium dodecylsulfate (SDS) system propose that the PNIPAM-surfactant interaction is purely hydrophobic. However, prior phenomenological investigations of a range of surfactant identities (anionic, cationic, nonionic) show that only anionic surfactants affect the thermoresponse and conformation of PNIPAM, implying that the hydrophilic head–group also contributes. Crucially, the phenomenological experiments do not measure the affinity of the tested surfactants to the polymer, only their effect on its behaviour. Experiments: We study the adsorption of six surfactants within a planar PNIPAM brush system, elucidating the polymer conformation, thermoresponse, and surfactant adsorption kinetics using ellipsometry, neutron reflectometry (NR), optical reflectometry and the quartz crystal microbalance technique. NR is used to measure the distribution of surfactants within the brush. Findings: We find that only anionic surfactants modify the structure and thermoresponse of PNIPAM, with the greater affinity of anionic surfactants for PNIPAM (relative to cationic and nonionic surfactants) being the primary reason for this behaviour. These results show that the surfactant head–group has a more critical role in mediating PNIPAM-surfactant interaction than previously reported. Taking inspiration from prior molecular dynamics work on the PEO-surfactant system, we propose an interaction mechanism for PNIPAM and SDS that reconciles evidence for hydrophobic interaction with the observed head–group-dependent affinity.</p

    Strong coupling in molecular systems: a simple predictor employing routine optical measurements

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    We provide a simple method that enables readily acquired experimental data to be used to predict whether or not a candidate molecular material may exhibit strong coupling. Specifically, we explore the relationship between the hybrid molecular/photonic (polaritonic) states and the bulk optical response of the molecular material. For a given material this approach enables a prediction of the maximum extent of strong coupling (vacuum Rabi splitting), irrespective of the nature of the confined light field. We provide formulae for the upper limit of the splitting in terms of the molar absorption coefficient, the attenuation coefficient, the extinction coefficient (imaginary part of the refractive index) and the absorbance. To illustrate this approach we provide a number of examples, we also discuss some of the limitations of our approach
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