1,844 research outputs found

    The Feasibility of Wood and its Derivatives as a Bicycle Frame Building Material

    Full text link
    [EN] The bicycle is often considered as one of the most important inventions of all time. In addition, it is the most efficient form of human transport in the world. It is non pollutant, uses no fuel other than human power and its carbon footprint is neutralised in a short time. Today, faced with the threat of global warming brought about by fossil fuels, countries such as Denmark, the Netherlands and Columbia actually encourage the use of the bicycle as a viable means of urban transport, and in the city of Paris there are financial incentives for cycling commuters. In China alone there are 450 Million bicycles. The form of the bicycle is universally recognisable, it is easy to use and simple to maintain. However, in spite of its apparent simplicity, the bicycle is made up of numerous components and sub-assemblies. Over the years these components and sub-assemblies have undergone a succession of changes and modifications. As with the evolution, development, and life cycle of any product, some of the modifications were relatively short lived. Others for various reasons have been adopted almost universally, such as steel ball bearings, the roller chain, pneumatic tires, tension spoked wheels, etc. In order to more fully understand the bicycle, its advantages, its shortcomings, and its place in the modern world, the first part of this study aims to address the various criteria which apply to bicycle typology, differentiation, use and construction. However, although numerous types of Human Powered Vehicles (HPVs) exist, the initial part of this research is constrained to the evolution and development of the "Safety" type bicycle - attributed to J. K. Starley of Coventry in 1895 - up to the present day, taking into account such factors as; design, material selection, manufacturing technology, and diversity. The first part of the study is a comprehensive overview of the bicycle which identifies crucial technological aspects and categorises bicycle by type and intended use. Due to the huge quantities and types of bicycles produced worldwide this research identifies generic types of each category irrespective of origin or manufacturer. The second part of this dissertation is devoted to the study of wooden bicycles and the specific requirements of this type of bicycle such as the use of wood and its derivatives e.g. engineered wood, as a bicycle frame construction material and some of the solutions arrived at and the special parts or components required. Contemporary and historical bicycles made from wood, other organic material and its derivatives have been investigated and conclusions drawn regarding their functionality and purpose. Part three is dedicated to the Design, Development, and Evaluation of a Wooden Bicycle prototype undertaken by the Author with the assistance of three Industrial Design Students. Part four describes the design, construction and testing of subsequent prototypes in detail including the fabrication of pre-production bicycles and proposals for manufacture on a commercial level. Parts five and six outline the empirical findings from the previous section and attempt to define strategies for marketing bicycles manufactured from wood and its derivatives as an alternative to conventional materials with a view to reanimating small local industries which have a strong base of expertise and knowhow working with wood, such as producers of furniture and similar products (broom handles, tool handles, boxes etc.). Part seven is devoted to the potential diversification of wooden framed bicycles which are electrically assisted. The fabrication of a prototype is discussed but no conclusions were made due to constraints beyond my control. Keywords: Design, Product, Frame, Bicycle[ES] La bicicleta es frecuentemente considerada como una de las invenciones más importantes de todos los tiempos. Es también una de las formas de transporte humano más eficiente en el mundo. Hoy en día, por la amenaza del calentamiento global provocado por las fuentes de energía no renovables, países como Dinamarca, Holanda y Colombia animan a usar la bicicleta como un medio de transporte urbano. La figura de la bicicleta es universalmente reconocida, es fácil de usar y su mantenimiento es simple. A pesar de su aparente simplicidad, la bicicleta está compuesta de numerosos componentes y subconjuntos. A lo largo de los años, los subconjuntos sufrieron una serie de cambios y transformaciones. Como en cualquier evolución y desarrollo, los cambios influyen en el ciclo de vida de cualquier producto, a pesar que algunas de estas aportaciones tuvieron una vida efímera. Otras, por razones varias, fueron adoptadas casi universalmente. Entre estas podemos citar los rodamientos de esferas de azor, la cadena, los neumáticos, etc. Para comprender mejor el producto bicicleta, se ha considerado como objetivo en la primera parte de este estudio, abordar varios criterios que se aplican de acuerdo con la tipología, diferenciación, uso y construcción de la bicicleta. A pesar de existir numerosos tipos de Human Powered Vehicles (HPVs), la primera parte de esta investigación se limita al estudio de la evaluación y desenvolvimiento de la bicicleta "Safety" atribuida A J.K. Starley de Coventry UK.1895, desde su aparición hasta nuestros días, tomando en consideración la selección de materiales, las tecnologías de fabricación, el diseño, y el estatus de la bicicleta en la sociedad. La segunda parte de esta tesis está dedicada por completo al estudio de la madera y sus derivados como material de construcción de la bicicleta. Bicicletas contemporáneas e históricas de madera y sus derivados, que han sido investigados y se han presentado los resultados en relación a su funcionalidad y propósito. La tercera parte describe con detalle el diseño, desarrollo y evaluación de una bicicleta prototipo de madera, los prototipos posteriores y las bicicletas prototipo o de pre-producción de madera y sus derivados fabricados por el autor con la ayuda de los Estudiantes finalistas del grado de Diseño Industrial (ESTGAD CR, Portugal) En la cuarta parte se describe el diseño, construcción y prueba de prototipos posteriores en detalle, incluyendo la fabricación de bicicletas de pre-producción y propuestas para la fabricación a nivel comercial. La quinta y sexto partes resume los resultados empíricos de la sección anterior y trata de definir estrategias de marketing, para bicicletas fabricadas a partir de la madera y sus derivados como una alternativa a los materiales convencionales, con el fin de animar a producción industrial a las pequeñas industrias locales, que poseen una base sólida de experiencia en el trabajo con la madera, como productores de muebles y productos similares. En la última parte, se ha dedicado a la diversificación potencial de cuadros de bicicletas en madera que están asistidas eléctricamente. La fabricación de un prototipo forma parte de la discusión y pretende ser una proyección de futuro. Palabras Clave: Diseño, Producto, Madera, Bicicleta.[CA] La bicicleta es freqüentment considerada com una de les invencions mes importants de tots els temps. Es tambe una de les formes de transport huma mes eficient en el mon. Hui en dia, per l'amenaça del calfament global provocat per les fonts d'energia no renovellables, països com Dinamarca, Holanda i Colombia animen a usar la bicicleta com un mig de transport urba. La figura de la bicicleta es universalment reconeguda, es facil d'usar i el seu manteniment es simple. A pesar de la seua aparent simplicitat, la bicicleta està composta de numerosos components i subconjuntos. A lo llarc dels anys, els subconjuntos patiren una serie de canvis i transformacions. Com en qualsevol evolucio i desenroll, els canvis influixen en el cicle de vida de qualsevol producte, a pesar que algunes d'estos aportaments tingueren una vida efimera. Atres, per raons varies, foren adoptades casi universalment. Entre estes podem citar els rodaments d'esferes d'azor, la cadena, els neumatics, etc. Per a comprendre millor el producte bicicleta, s'ha considerat com objectiu en la primera part d'este estudi, abordar varis criteris que s'apliquen d'acort en la tipología, diferenciacio, us i construccio de la bicicleta. A pesar d'existir numerosos tipos d'Human Powered Vehicles (HPVS), la primera part d'esta investigacio se llimita a l'estudi de l'evaluacio i desenvolupament de la bicicleta "Safety" atribuida A J.K. Starley de Coventry UK. 1895, des de la seua aparicio fins nostres dies, prenent en consideracio la seleccio de materials, les tecnologies de fabricacio, el disseny, i l'estat de la bicicleta en la societat. La segona part d'esta tesis està dedicada per complet a l'estudi de la fusta i els seus derivats com material de construccio de la bicicleta. Bicicletes contemporanees i historiques de fusta i els seus derivats, que han segut investigats i s'han presentat els resultats en relacio a la seua funcionalitat i proposit. La tercera part descriu en detall el disseny, desenroll i evaluacio d'una bicicleta prototip de fusta, els prototips posteriors i les bicicletes prototip o de PRE-produccio de fusta i els seus derivats fabricats per l'autor en l'ajuda dels Estudiants finalistes del grau de Disseny Industrial (ESTGAD CR, Portugal) En la quarta part se descriu el disseny, construccio i prova de prototips posteriors en detall, incloent la fabricacio de bicicletes de pre-produccio i propostes per a la fabricacio a nivell comercial. La quinta i sisè parts resumix els resultats empirics de la seccio anterior i tracta de definir estrategies de marketing, per a bicicletes fabricades a partir de la fusta i els seus derivats com una alternativa als materials convencionals, en el fi d'animar a produccio industrial a les menudes industries locals, que posseixen una base solida d'experiencia en el treball en la fusta, com productors de mobles i productes similars. En l'ultima part, s'ha dedicat a la diversificacio potencial de quadros de bicicletes en fusta que estan assistides electricament. La fabricacio d'un prototip forma part de la discussio i preten ser una proyeccio de futur. Paraules Clau: Disseny, Producte, Fusta, Bicicleta.Brent Taylor, N. (2016). The Feasibility of Wood and its Derivatives as a Bicycle Frame Building Material [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63663TESI

    Experimental Infection of North American Birds with the New York 1999 Strain of West Nile Virus

    Get PDF
    To evaluate transmission dynamics, we exposed 25 bird species to West Nile virus (WNV) by infectious mosquito bite. We monitored viremia titers, clinical outcome, WNV shedding (cloacal and oral), seroconversion, virus persistence in organs, and susceptibility to oral and contact transmission. Passeriform and charadriiform birds were more reservoir competent (a derivation of viremia data) than other species tested. The five most competent species were passerines: Blue Jay (Cyanocitta cristata), Common Grackle (Quiscalus quiscula), House Finch (Carpodacus mexicanus), American Crow (Corvus brachyrhynchos), and House Sparrow (Passer domesticus). Death occurred in eight species. Cloacal shedding of WNV was observed in 17 of 24 species, and oral shedding in 12 of 14 species. We observed contact transmission among four species and oral in five species. Persistent WNV infections were found in tissues of 16 surviving birds. Our observations shed light on transmission ecology of WNV and will benefit surveillance and control programs

    The SAMI Galaxy Survey : spatially resolving the main sequence of star formation

    Get PDF
    We present the ∼800 star formation rate maps for the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey based on H α emission maps, corrected for dust attenuation via the Balmer decrement, that are included in the SAMI Public Data Release 1. We mask out spaxels contaminated by non-stellar emission using the [O iii]/H β, [N ii]/H α, [S ii]/H α, and [O i]/H α line ratios. Using these maps, we examine the global and resolved star-forming main sequences of SAMI galaxies as a function of morphology, environmental density, and stellar mass. Galaxies further below the star-forming main sequence are more likely to have flatter star formation profiles. Early-type galaxies split into two populations with similar stellar masses and central stellar mass surface densities. The main-sequence population has centrally concentrated star formation similar to late-type galaxies, while galaxies >3σ below the main sequence show significantly reduced star formation most strikingly in the nuclear regions. The split populations support a two-step quenching mechanism, wherein halo mass first cuts off the gas supply and remaining gas continues to form stars until the local stellar mass surface density can stabilize the reduced remaining fuel against further star formation. Across all morphologies, galaxies in denser environments show a decreased specific star formation rate from the outside in, supporting an environmental cause for quenching, such as ram-pressure stripping or galaxy interactions.Publisher PDFPeer reviewe

    brainlife.io: A decentralized and open source cloud platform to support neuroscience research

    Full text link
    Neuroscience research has expanded dramatically over the past 30 years by advancing standardization and tool development to support rigor and transparency. Consequently, the complexity of the data pipeline has also increased, hindering access to FAIR data analysis to portions of the worldwide research community. brainlife.io was developed to reduce these burdens and democratize modern neuroscience research across institutions and career levels. Using community software and hardware infrastructure, the platform provides open-source data standardization, management, visualization, and processing and simplifies the data pipeline. brainlife.io automatically tracks the provenance history of thousands of data objects, supporting simplicity, efficiency, and transparency in neuroscience research. Here brainlife.io's technology and data services are described and evaluated for validity, reliability, reproducibility, replicability, and scientific utility. Using data from 4 modalities and 3,200 participants, we demonstrate that brainlife.io's services produce outputs that adhere to best practices in modern neuroscience research

    Improved imputation of low-frequency and rare variants using the UK10K haplotype reference panel

    Get PDF
    Imputing genotypes from reference panels created by whole-genome sequencing (WGS) provides a cost-effective strategy for augmenting the single-nucleotide polymorphism (SNP) content of genome-wide arrays. The UK10K Cohorts project has generated a data set of 3,781 whole genomes sequenced at low depth (average 7x), aiming to exhaustively characterize genetic variation down to 0.1% minor allele frequency in the British population. Here we demonstrate the value of this resource for improving imputation accuracy at rare and low-frequency variants in both a UK and an Italian population. We show that large increases in imputation accuracy can be achieved by re-phasing WGS reference panels after initial genotype calling. We also present a method for combining WGS panels to improve variant coverage and downstream imputation accuracy, which we illustrate by integrating 7,562 WGS haplotypes from the UK10K project with 2,184 haplotypes from the 1000 Genomes Project. Finally, we introduce a novel approximation that maintains speed without sacrificing imputation accuracy for rare variants

    A communal catalogue reveals Earth’s multiscale microbial diversity

    Get PDF
    Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity

    A communal catalogue reveals Earth's multiscale microbial diversity

    Get PDF
    Our growing awareness of the microbial world's importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth's microbial diversity.Peer reviewe

    New genetic loci link adipose and insulin biology to body fat distribution.

    Get PDF
    Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

    Common, low-frequency, rare, and ultra-rare coding variants contribute to COVID-19 severity

    Get PDF
    The combined impact of common and rare exonic variants in COVID-19 host genetics is currently insufficiently understood. Here, common and rare variants from whole-exome sequencing data of about 4000 SARS-CoV-2-positive individuals were used to define an interpretable machine-learning model for predicting COVID-19 severity. First, variants were converted into separate sets of Boolean features, depending on the absence or the presence of variants in each gene. An ensemble of LASSO logistic regression models was used to identify the most informative Boolean features with respect to the genetic bases of severity. The Boolean features selected by these logistic models were combined into an Integrated PolyGenic Score that offers a synthetic and interpretable index for describing the contribution of host genetics in COVID-19 severity, as demonstrated through testing in several independent cohorts. Selected features belong to ultra-rare, rare, low-frequency, and common variants, including those in linkage disequilibrium with known GWAS loci. Noteworthily, around one quarter of the selected genes are sex-specific. Pathway analysis of the selected genes associated with COVID-19 severity reflected the multi-organ nature of the disease. The proposed model might provide useful information for developing diagnostics and therapeutics, while also being able to guide bedside disease management. © 2021, The Author(s)

    AI is a viable alternative to high throughput screening: a 318-target study

    Get PDF
    : High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery
    corecore