336 research outputs found

    Mise en pratique for the definition of the candela and associated derived units for photometric and radiometric quantities in the International System of Units (SI)

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    open8The purpose of this mise en pratique, prepared by the Consultative Committee for Photometry and Radiometry (CCPR) of the International Committee for Weights and Measures (CIPM) and formally adopted by the CIPM, is to provide guidance on how the candela and related units used in photometry and radiometry can be realized in practice. The scope of the mise en pratique recognizes the fact that the two fields of photometry and radiometry and their units are closely related through the current definition of the SI base unit for the photometric quantity, luminous intensity: the candela. The previous version of the mise en pratique was applied only to the candela whereas this updated version covers the realization of the candela and other related units used for photometric and radiometric quantities. Recent advances in the generation and manipulation of individual photons show great promise of producing radiant fluxes with a well-established number of photons. Thus, this mise en pratique also includes information on the practical realization of units for photometric and radiometric quantities using photon-number-based techniques. In the following, for units used for photometric and radiometric quantities, the shorter term, photometric and radiometric units, is generally used. Section 1 describes the definition of the candela which introduces a close relationship between photometric and radiometric units. Sections 2 and 3 describe the practical realization of radiometric and photon-number-based units, respectively. Section 4.1 explains how, in general, photometric units are derived from radiometric units. Sections 4.2–4.5 deal with the particular geometric conditions for the specific photometric units. Section 5 deals very briefly with the topic of determination of measurement uncertainties in photometry.openZwinkels, Joanne; Sperling, Armin; Goodman, Teresa; Acosta, Joaquin Campos; Ohno, Yoshi; Rastello, Maria Luisa; Stock, Michael; Woolliams, EmmaZwinkels, Joanne; Sperling, Armin; Goodman, Teresa; Acosta, Joaquin Campos; Ohno, Yoshi; Rastello, Maria Luisa; Stock, Michael; Woolliams, Emm

    Ethical Implications of Modifying Lethal Injection Protocols

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    Teresa Zimmers and colleagues argue that it is difficult to conceive how lethal injection research activities could be carried out in a fashion consistent with ethical norms

    Peripheral blood DNA methylation and neuroanatomical responses to HDACi treatment that rescues neurological deficits in a Kabuki syndrome mouse model

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    Publisher Copyright: © 2023, The Author(s). © 2023. The Author(s).Background: Recent findings from studies of mouse models of Mendelian disorders of epigenetic machinery strongly support the potential for postnatal therapies to improve neurobehavioral and cognitive deficits. As several of these therapies move into human clinical trials, the search for biomarkers of treatment efficacy is a priority. A potential postnatal treatment of Kabuki syndrome type 1 (KS1), caused by pathogenic variants in KMT2D encoding a histone-lysine methyltransferase, has emerged using a mouse model of KS1 (Kmt2d +/ÎČGeo). In this mouse model, hippocampal memory deficits are ameliorated following treatment with the histone deacetylase inhibitor (HDACi), AR-42. Here, we investigate the effect of both Kmt2d +/ÎČGeo genotype and AR-42 treatment on neuroanatomy and on DNA methylation (DNAm) in peripheral blood. While peripheral blood may not be considered a “primary tissue” with respect to understanding the pathophysiology of neurodevelopmental disorders, it has the potential to serve as an accessible biomarker of disease- and treatment-related changes in the brain. Methods: Half of the KS1 and wildtype mice were treated with 14 days of AR-42. Following treatment, fixed brain samples were imaged using MRI to calculate regional volumes. Blood was assayed for genome-wide DNAm at over 285,000 CpG sites using the Illumina Infinium Mouse Methylation array. DNAm patterns and brain volumes were analyzed in the four groups of animals: wildtype untreated, wildtype AR-42 treated, KS1 untreated and KS1 AR-42 treated. Results: We defined a DNAm signature in the blood of KS1 mice, that overlapped with the human KS1 DNAm signature. We also found a striking 10% decrease in total brain volume in untreated KS1 mice compared to untreated wildtype, which correlated with DNAm levels in a subset KS1 signature sites, suggesting that disease severity may be reflected in blood DNAm. Treatment with AR-42 ameliorated DNAm aberrations in KS1 mice at a small number of signature sites. Conclusions: As this treatment impacts both neurological deficits and blood DNAm in mice, future KS clinical trials in humans could be used to assess blood DNAm as an early biomarker of therapeutic efficacy.Peer reviewe

    Geodesic flows on hyperbolic orbifolds, and universal orbifolds

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    The authors discuss a class of flows on 3-manifolds closely related to Anosov flows, which they call singular Anosov flows. These are flows which are Anosov outside of a finite number of periodic "singular orbits'', such that each singular orbit has a PoincarĂ© section on which the first return map has an "n-pronged singularity'' for some n≄1, n≠2. If only 1-pronged singularities occur the flow is called V-Anosov; the authors observe, for example, that the geodesic flow of a compact, hyperbolic 2-orbifold is V-Anosov. The main theorem is that every closed 3-manifold has a singular Anosov flow. The theorem is proved by constructing a certain link L in the 3-sphere such that L is a universal branching link, so every closed 3-manifold M is a branched cover of the 3-sphere branched over L, and L is the set of singular orbits of some V-Anosov flow on S3, so the lifted flow is a singular Anosov flow on M. In the literature, a singular Anosov flow whose n-pronged singularities always satisfy n≄3 is called pseudo-Anosov. The main theorem should be contrasted with the fact that an Anosov or pseudo-Anosov flow can only occur on an aspherical 3-manifold—an irreducible 3-manifold with infinite fundamental group. The literature contains many constructions of Anosov and pseudo-Anosov flows, but it remains unknown exactly which aspherical 3-manifolds support such flow

    An integrative approach to characterize Malagasy bats of the subfamily Vespertilioninae Gray, 1821, with the description of a new species of Hypsugo

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    Although important advances have been made in recent years in the taxonomy of different families and subfamilies of Malagasy bats, those belonging to the Vespertilioninae remain partially unresolved. Herein using a mitochondrial marker (cytochrome b) as the point of departure for 76 specimens of Malagasy vespers and appropriate African taxa, we diagnose the six taxa of this subfamily on the island by overlaying different morphological and bioacoustic characters on the clade structure of sequenced animals. The species include: endemic Neoromicia matroka, which is sister to African N. capensis; endemics N. malagasyensis and N. robertsi, which form sister species; a member of the genus Hypsugo, which is sister to African H. anchietae and described herein as new to science; Pipistrellus hesperidus for which Madagascar animals are genetically close but distinct from African populations of the same species; and endemic P. raceyi, which shows segregation of eastern (mesic) and western (dry) populations and its sister species relationships are unresolved. While the external and craniodental measurements, as well as bioacoustics variables, allow only partial differentiation of these six species of Vespertilioninae, molecular characters provide definitive separation of the taxa, as do male bacular morphology.Irene D. Pritzker Foundation associated with the Field Museum of Natural History African Training Fund; John D and Catherine T.MacArthur Foundation; Volkswagen Foundation; and the Centre de Recherche et de Veille sur les maladies Ă©mergentes dans l’OcĂ©an Indien (CRVOI) through the Fonds EuropĂ©en de DĂ©veloppement RĂ©gional Programme OpĂ©rationnel de CoopĂ©ration Territoriale RĂ©union, pathogĂšnes associĂ©s Ă  la faune sauvage ocean Indien #31189. SYNTHESYS project http://synthesys.info/, which is financed by European Community Research Infrastructure Action under the FP7 Integrating Activities Program.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1096-36422016-04-30hb2015Zoology and EntomologyMammal Research Institut

    Common \u3cem\u3eTDP1\u3c/em\u3e Polymorphisms in Relation to Survival Among Small Cell Lung Cancer Patients: A Multicenter Study from the International Lung Cancer Consortium

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    Background—DNA topoisomerase inhibitors are commonly used for treating small-cell lung cancer (SCLC). Tyrosyl-DNA phosphodiesterase (TDP1) repairs DNA damage caused by this class of drugs and may therefore influence treatment outcome. In this study, we investigated whether common TDP1 single-nucleotide polymorphisms (SNP) are associated with overall survival among SCLC patients. Methods—Two TDP1 SNPs (rs942190 and rs2401863) were analyzed in 890 patients from 10 studies in the International Lung Cancer Consortium (ILCCO). The Kaplan–Meier method and Cox regression analyses were used to evaluate genotype associations with overall mortality at 36 months postdiagnosis, adjusting for age, sex, race, and tumor stage. Results—Patients homozygous for the minor allele (GG) of rs942190 had poorer survival compared with those carrying AA alleles, with a HR of 1.36 [95% confidence interval (CI): 1.08–1.72, P = 0.01), but no association with survival was observed for patients carrying the AG genotype (HR = 1.04, 95% CI, 0.84–1.29, P = 0.72). For rs2401863, patients homozygous for the minor allele (CC) tended to have better survival than patients carrying AA alleles (HR = 0.79; 95% CI, 0.61–1.02, P = 0.07). Results from the Genotype Tissue Expression (GTEx) Project, the Encyclopedia of DNA Elements (ENCODE), and the ePOSSUM web application support the potential function of rs942190. Conclusions—We found the rs942190 GG genotype to be associated with relatively poor survival among SCLC patients. Further investigation is needed to confirm the result and to determine whether this genotype may be a predictive marker for treatment efficacy of DNA topoisomerase inhibitors

    A 500-year tale of co-evolution, adaptation, and virulence: Helicobacter pylori in the Americas

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    Helicobacter pylori is a common component of the human stomach microbiota, possibly dating back to the speciation of Homo sapiens. A history of pathogen evolution in allopatry has led to the development of genetically distinct H. pylori subpopulations, associated with different human populations, and more recent admixture among H. pylori subpopulations can provide information about human migrations. However, little is known about the degree to which some H. pylori genes are conserved in the face of admixture, potentially indicating host adaptation, or how virulence genes spread among different populations. We analyzed H. pylori genomes from 14 countries in the Americas, strains from the Iberian Peninsula, and public genomes from Europe, Africa, and Asia, to investigate how admixture varies across different regions and gene families. Whole-genome analyses of 723 H. pylori strains from around the world showed evidence of frequent admixture in the American strains with a complex mosaic of contributions from H. pylori populations originating in the Americas as well as other continents. Despite the complex admixture, distinctive genomic fingerprints were identified for each region, revealing novel American H. pylori subpopulations. A pan-genome Fst analysis showed that variation in virulence genes had the strongest fixation in America, compared with non-American populations, and that much of the variation constituted non-synonymous substitutions in functional domains. Network analyses suggest that these virulence genes have followed unique evolutionary paths in the American populations, spreading into different genetic backgrounds, potentially contributing to the high risk of gastric cancer in the region.Fil: Muñoz Ramirez, Zilia Y.. INSTITUTO POLITÉCNICO NACIONAL (IPN);Fil: Pascoe, Ben. University of Bath; Reino UnidoFil: Mendez Tenorio, Alfonso. INSTITUTO POLITÉCNICO NACIONAL (IPN);Fil: Mourkas, Evangelos. University of Bath; Reino UnidoFil: Sandoval Motta, Santiago. Consejo Nacional de Ciencia y TecnologĂ­a; MĂ©xicoFil: Perez Perez, Guillermo. New York University Langone Medical Center; Estados UnidosFil: Morgan, Douglas R.. University of Alabama at Birmingahm; Estados UnidosFil: Dominguez, Ricardo Leonel. Western Honduras Gastric Cancer Prevention Initiative Hospital de Occidente Santa Rosa de Copan; HondurasFil: Ortiz Princz, Diana. No especifĂ­ca;Fil: Cavazza, Maria Eugenia. No especifĂ­ca;Fil: Rocha, Gifone. Universidade Federal de Minas Gerais; BrasilFil: Queiroz, Dulcienne. Universidade Federal de Minas Gerais; BrasilFil: Catalano, Mariana. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones en MicrobiologĂ­a y ParasitologĂ­a MĂ©dica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en MicrobiologĂ­a y ParasitologĂ­a MĂ©dica; ArgentinaFil: Zerbetto de Palma, Gerardo Gabriel. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂ­mica y FĂ­sico-QuĂ­mica BiolĂłgicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y BioquĂ­mica. Instituto de QuĂ­mica y FĂ­sico-QuĂ­mica BiolĂłgicas; ArgentinaFil: Goldman, Cinthia Gabriela. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂ­mica; ArgentinaFil: Venegas, Alejandro. Universidad Diego Portales; ChileFil: Alarcon, Teresa. Universidad AutĂłnoma de Madrid; EspañaFil: Oleastro, Monica. Universidade Nova de Lisboa; PortugalFil: Vale, Filipa F.. Universidade Nova de Lisboa; PortugalFil: Goodman, Karen J.. University of Alberta; CanadĂĄFil: Torres, Roberto C.. Instituto Mexicano del Seguro Social; MĂ©xicoFil: Berthenet, Elvire. Swansea University Medical School; Reino UnidoFil: Hitchings, Matthew D.. Swansea University Medical School; Reino UnidoFil: Blaser, Martin J.. Rutgers University; Estados UnidosFil: Sheppard, Samuel K.. University of Bath; Reino UnidoFil: Thorell, Kaisa. University of Gothenburg; SueciaFil: Torres, Javier. Instituto Mexicano del Seguro Social; MĂ©xic

    Benchmarking spike-based visual recognition: a dataset and evaluation

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    Today, increasing attention is being paid to research into spike-based neural computation both to gain a better understanding of the brain and to explore biologically-inspired computation. Within this field, the primate visual pathway and its hierarchical organisation have been extensively studied. Spiking Neural Networks (SNNs), inspired by the understanding of observed biological structure and function, have been successfully applied to visual recognition and classification tasks. In addition, implementations on neuromorphic hardware have enabled large-scale networks to run in (or even faster than) real time, making spike-based neural vision processing accessible on mobile robots. Neuromorphic sensors such as silicon retinas are able to feed such mobile systems with real-time visual stimuli. A new set of vision benchmarks for spike-based neural processing are now needed to measure progress quantitatively within this rapidly advancing field. We propose that a large dataset of spike-based visual stimuli is needed to provide meaningful comparisons between different systems, and a corresponding evaluation methodology is also required to measure the performance of SNN models and their hardware implementations. In this paper we first propose an initial NE (Neuromorphic Engineering) dataset based on standard computer vision benchmarks and that uses digits from the MNIST database. This dataset is compatible with the state of current research on spike-based image recognition. The corresponding spike trains are produced using a range of techniques: rate-based Poisson spike generation, rank order encoding, and recorded output from a silicon retina with both flashing and oscillating input stimuli. In addition, a complementary evaluation methodology is presented to assess both model-level and hardware-level performance. Finally, we demonstrate the use of the dataset and the evaluation methodology using two SNN models to validate the performance of the models and their hardware implementations. With this dataset we hope to (1) promote meaningful comparison between algorithms in the field of neural computation, (2) allow comparison with conventional image recognition methods, (3) provide an assessment of the state of the art in spike-based visual recognition, and (4) help researchers identify future directions and advance the field
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