664 research outputs found

    Design and Development of a Myoelectric Transradial Prosthesis

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    The loss of a limb is a life-changing event and reality for 441,000 transradial amputees in the United States. Limb loss can have substantial physical, social, psychological, and economic consequences. A prototype prosthesis was created that has sophisticated hand functionality, an adjustable and comfortable socket, and a lightweight yet durable design utilizing 3D printing, all available at a reasonable price point. The prosthesis integrated force sensors, servo motors, and a myoelectric means of control so the user may perform activities of daily living. The overall outcome was a prosthesis that met its design requirements, offering increased usability, functionality, and availability

    The role of symbiont genetic distance and potential adaptability in host preference towards Pseudonocardia symbionts in <i>Acromyrmex</i> leaf-cutting ants

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    Fungus-growing ants display symbiont preference in behavioral assays, both towards the fungus they cultivate for food and Actinobacteria they maintain on their cuticle for antibiotic production against parasites. These Actinobacteria, genus Pseudonocardia Henssen (Pseudonocardiacea: Actinomycetales), help defend the ants' fungal mutualist from specialized parasites. In Acromyrmex Mayr (Hymenoptera: Formicidae) leaf-cutting ants, individual colonies maintain either a single or a few strains of Pseudonocardia, and the symbiont is primarily vertically transmitted between generations by colony-founding queens. A recent report found that Acromyrmex workers are able to differentiate between their native Pseudonocardia strain and non-native strains isolated from sympatric or allopatric Acromyrmex species, and show preference for their native strain. Here we explore worker preference when presented with two non-native strains, elucidating the role of genetic distance on preference between strains and Pseudonocardia origin. Our findings suggest that ants tend to prefer bacteria more closely related to their native bacterium and that genetic similarity is probably more important than whether symbionts are ant-associated or free-living. Preliminary findings suggest that when continued exposure to a novel Pseudonocardia strain occurs, ant symbiont preference is potentially adaptable, with colonies apparently being able to alter symbiont preference over time. These findings are discussed in relation to the role of adaptive recognition, potential ecological flexibility in symbiont preference, and more broadly, in relation to self versus non-self recognition

    Assessing Smart City Initiatives in Kowloon East

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    The area of Kowloon East is in need of redevelopment and a plan is in place to do so. Our project focused on evaluating the proposed plan and determining which parts encouraged Smart City growth. We chose to focus on connectivity throughout the area and identify ways that would improve upon the existing plan. Using observations, a survey and interviews we developed suggestions that can improve the connectivity of Kowloon East, and also community participation and the region’s imag

    Agricultural productivity in past societies: toward an empirically informed model for testing cultural evolutionary hypotheses

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    Agricultural productivity, and its variation in space and time, plays a fundamental role in many theories of human social evolution. However, we often lack systematic information about the productivity of past agricultural systems on a scale large enough to test these theories properly. The effect of climate on crop yields has received a great deal of attention resulting in a range of empirical and process-based models, yet the focus has primarily been on current or future conditions. In this paper, we argue for a “bottom-up” approach that estimates potential productivity based on information about the agricultural practices and technologies used in past societies. Of key theoretical interest is using this information to estimate the carrying high quality historical and archaeological information about past societies in order to infer the temporal and geographic patterns of change in agricultural productivity and potential. We discuss information we need to collect about past agricultural techniques and practices, and introduce a new databank initiative that we have developed for collating the best available historical and archaeological evidence. A key benefit of our approach lies in making explicit the steps in the estimation of past productivities and carrying capacities, and in being able to assess the effects of different modelling assumptions. This is undoubtedly an ambitious task, yet promises to provide important insights into fundamental aspects of past societies, enabling us to test more rigorously key hypotheses about human socio-cultural evolution

    Pollen Streptomyces Produce Antibiotic That Inhibits the Honey Bee Pathogen Paenibacillus larvae

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    Humans use natural products to treat disease; similarly, some insects use natural products produced by Actinobacteria to combat infectious pathogens. Honey bees, Apis mellifera, are ecologically and economically important for their critical role as plant pollinators and are host to diverse and potentially virulent pathogens that threaten hive health. Here, we provide evidence that Actinobacteria that can suppress pathogenic microbes are associated with A. mellifera. We show through culture-dependent approaches that Actinobacteria in the genus Streptomyces are commonly isolated from foraging bees, and especially common in pollen stores. One strain, isolated from pollen stores, exhibited pronounced inhibitory activity against Paenibacillus larvae, the causative agent of American foulbrood. Bioassay-guided HPLC fractionation, followed by NMR and mass spectrometry, identified the known macrocyclic polyene lactam, piceamycin that was responsible for this activity. Further, we show that in its purified form, piceamycin has potent inhibitory activity toward P. larvae. Our results suggest that honey bees may use pollen-derived Actinobacteria and their associated small molecules to mediate colony health. Given the importance of honey bees to modern agriculture and their heightened susceptibility to disease, the discovery and development of antibiotic compounds from hives could serve as an important strategy in supporting disease management within apiaries.National Institute for Health/[U19 AI142720]/NIH/Estados UnidosNational Institute of Food and Agriculture/[WISO1321]/NIFA/Estados UnidosUCR::VicerrectorĂ­a de InvestigaciĂłn::Unidades de InvestigaciĂłn::Ciencias BĂĄsicas::Centro de InvestigaciĂłn en Estructuras MicroscĂłpicas (CIEMIC)UCR::VicerrectorĂ­a de InvestigaciĂłn::Unidades de InvestigaciĂłn::Ciencias BĂĄsicas::Centro de InvestigaciĂłn en BiologĂ­a Celular y Molecular (CIBCM

    Examination of the risk of reinfection with hepatitis C among injecting drug users who have been tested in Glasgow

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    Unsafe injecting practices put injecting drug users (IDUs) at repeat exposure to infection with the hepatitis C virus (HCV). It has not yet been determined if spontaneously clearing one's primary infection influences the risk of reinfection; our aim was to estimate the relative risk of reinfection in IDUs who have cleared the virus. We conducted a retrospective study using a large database of HCV test results covering Greater Glasgow Health Board during 1993–2007 to calculate rates of infection and reinfection in current/former IDUs. The relative risk of (re)infection in previously infected compared with never-infected IDUs was estimated using Poisson regression, adjusting for age at study entry, sex, and calendar period of test. Although the rate of reinfection in IDUs who were HCV antibody-positive, RNA-negative at baseline was lower (7/100 person-years, 95% CI: 5–9) than the rate of acute infection in IDUs who were HCV antibody-negative at baseline (10/100 person-years, 95% CI: 9–12), the risk of reinfection was not significantly different than the risk of initial infection (adjusted rate ratio = 0.78, 95% CI: 0.57–1.08). We found only weak evidence for a reduced risk of HCV reinfection in IDUs who had cleared their previous infection. Further research among those who have cleared infection through antiviral therapy is needed to help inform decisions regarding treatment of IDUs

    Review of the Constellation Level II Safety, Reliability, and Quality Assurance (SR&QA) Requirements Documents during Participation in the Constellation Level II SR&QA Forum

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    At the request of the Exploration Systems Mission Directorate (ESMD) and the Constellation Program (CxP) Safety, Reliability; and Quality Assurance (SR&QA) Requirements Director, the NASA Engineering and Safety Center (NESC) participated in the Cx SR&QA Requirements forum. The Requirements Forum was held June 24-26; 2008, at GRC's Plum Brook Facility. The forums purpose was to gather all stakeholders into a focused meeting to help complete the process of refining the CxP to refine its Level II SR&QA requirements or defining project-specific requirements tailoring. Element prime contractors had raised specific questions about the wording and intent of many requirements in areas they felt were driving costs without adding commensurate value. NESC was asked to provide an independent and thorough review of requirements that contractors believed were driving Program costs, by active participation in the forum. This document contains information from the forum

    Microtermolides A and B from Termite-Associated Streptomyces sp. and Structural Revision of Vinylamycin

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    Microtermolides A (1) and B (2) were isolated from a Streptomyces sp. strain associated with fungus-growing termites. The structures of 1 and 2 were determined by 1D- and 2D-NMR spectroscopy and high-resolution mass spectrometry. Structural elucidation of 1 led to the re-examination of the structure originally proposed for vinylamycin (3). Based on a comparison of predicted and experimental 1^1H and 13^{13}C NMR chemical shifts, we propose that vinylamycin’s structure be revised from 3 to 4

    First observation of Bs -> D_{s2}^{*+} X mu nu decays

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    Using data collected with the LHCb detector in proton-proton collisions at a centre-of-mass energy of 7 TeV, the semileptonic decays Bs -> Ds+ X mu nu and Bs -> D0 K+ X mu nu are detected. Two structures are observed in the D0 K+ mass spectrum at masses consistent with the known D^+_{s1}(2536) and $D^{*+}_{s2}(2573) mesons. The measured branching fractions relative to the total Bs semileptonic rate are B(Bs -> D_{s2}^{*+} X mu nu)/B(Bs -> X mu nu)= (3.3\pm 1.0\pm 0.4)%, and B(Bs -> D_{s1}^+ X munu)/B(Bs -> X mu nu)= (5.4\pm 1.2\pm 0.5)%, where the first uncertainty is statistical and the second is systematic. This is the first observation of the D_{s2}^{*+} state in Bs decays; we also measure its mass and width.Comment: 8 pages 2 figures. Published in Physics Letters
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