2,687 research outputs found

    The Impact of Digitisation Projects on the Work of Local Historians

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    Background: the methodology of historical research depends on a commitment to reporting and record keeping based on investigation of primary and secondary sources. This dependence on finding and assessing the reliability of information sources presents particular challenges to designers of information retrieval software intended to support historical research. Aim: this paper reports the results of a questionnaire distributed as the first phase of a research project intended to assess the information needs of historians working with original and/or digitised primary resources. We have been particularly interested in the work of “local” historians working with archives of local newspapers and with image collections that are in the process of being digitised. The prim ary aim at this stage was to discover whether these historians have a preference between original or digitised resources and to understand the reasons behind any preferences. In the longer term we aim to apply what we have learned to the development of a model of information seeking behaviour that can be used to guide the design of information retrieval applications supporting local historical research. Method: an online survey was distributed to historians in 43 universities in the UK. Results: The results show that historians make an interesting distinction between their preference for working with original documents and the greater “usefulness” of digitised resources. Conclusions: Historical research presents a number of unique challenges. Further research is needed into the unique aspects of the local historian’s information seeking behaviour. An important focus for this research will be the design of archival information retrieval systems that address these unique requirements

    PiDRAM: A Holistic End-to-end FPGA-based Framework for Processing-in-DRAM

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    Processing-using-memory (PuM) techniques leverage the analog operation of memory cells to perform computation. Several recent works have demonstrated PuM techniques in off-the-shelf DRAM devices. Since DRAM is the dominant memory technology as main memory in current computing systems, these PuM techniques represent an opportunity for alleviating the data movement bottleneck at very low cost. However, system integration of PuM techniques imposes non-trivial challenges that are yet to be solved. Design space exploration of potential solutions to the PuM integration challenges requires appropriate tools to develop necessary hardware and software components. Unfortunately, current specialized DRAM-testing platforms, or system simulators do not provide the flexibility and/or the holistic system view that is necessary to deal with PuM integration challenges. We design and develop PiDRAM, the first flexible end-to-end framework that enables system integration studies and evaluation of real PuM techniques. PiDRAM provides software and hardware components to rapidly integrate PuM techniques across the whole system software and hardware stack (e.g., necessary modifications in the operating system, memory controller). We implement PiDRAM on an FPGA-based platform along with an open-source RISC-V system. Using PiDRAM, we implement and evaluate two state-of-the-art PuM techniques: in-DRAM (i) copy and initialization, (ii) true random number generation. Our results show that the in-memory copy and initialization techniques can improve the performance of bulk copy operations by 12.6x and bulk initialization operations by 14.6x on a real system. Implementing the true random number generator requires only 190 lines of Verilog and 74 lines of C code using PiDRAM's software and hardware components.Comment: To appear in ACM Transactions on Architecture and Code Optimizatio

    Electrochemically stable tunnel-type α-MnO2-based cathode materials for rechargeable aqueous zinc-ion batteries

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    The purpose of this study is the synthesis of α-MnO2-based cathode materials for rechargeable aqueous zinc ion batteries by hydrothermal method using KMnO4 and MnSO4 as starting materials. The aim is to improve the understanding of Zn2+ insertion/de-insertion mechanisms. The as-prepared solid compounds were characterized by spectroscopy and microscopy techniques. X-ray diffraction showed that the hydrothermal reaction forms α-MnO2 and Ce4+-inserted MnO2 structures. Raman spectroscopy confirmed the formation of α-MnO2 with hexagonal MnO2 and Ce-MnO2 structures. Scanning electron microscopy (SEM) confirmed the formation of nanostructured MnO2 (nanofibers) and Ce-MnO2 (nanorods). The electrochemical performance of MnO2 was evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) tests in half-cells. CV results showed the reversible insertion/de-insertion of Zn2+ ions in MnO2 and Ce-MnO2. GCD cycling tests of MnO2 and Ce-MnO2 at 2500 mA/g demonstrated an impressive electrochemical performance, excellent cycling stability throughout 500 cycles, and high rate capability. The excellent electrochemical performance and the good cycling stability of MnO2 and Ce-MnO2 nanostructures by simple method makes them promising cathode materials for aqueous rechargeable zinc-ion batteries.This work was funded by Qatar University through its Collaborative Grants Funding Program with project number QUCG-CAS-21/23-602

    A Green's function approach to transmission of massless Dirac fermions in graphene through an array of random scatterers

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    We consider the transmission of massless Dirac fermions through an array of short range scatterers which are modeled as randomly positioned δ\delta- function like potentials along the x-axis. We particularly discuss the interplay between disorder-induced localization that is the hallmark of a non-relativistic system and two important properties of such massless Dirac fermions, namely, complete transmission at normal incidence and periodic dependence of transmission coefficient on the strength of the barrier that leads to a periodic resonant transmission. This leads to two different types of conductance behavior as a function of the system size at the resonant and the off-resonance strengths of the delta function potential. We explain this behavior of the conductance in terms of the transmission through a pair of such barriers using a Green's function based approach. The method helps to understand such disordered transport in terms of well known optical phenomena such as Fabry Perot resonances.Comment: 22 double spaced single column pages. 15 .eps figure

    Effects of Resistance Training of Peripheral Muscles Versus Respiratory Muscles in Older Adults With Sarcopenia Who are Institutionalized: A Randomized Controlled Trial

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    [EN] This study compares the effects of two resistance training programs in peripheral and respiratory musculature on muscle mass and strength and physical performance and identifies the appropriate muscle mass parameter for assessing the intervention effects. Thirty-seven institutionalized older Spanish adults with sarcopenia were analyzed: control group (n = 17), respiratory muscle training group (n = 9), and peripheral muscle training group (n = 11). Measured outcomes were appendicular skeletal muscle mass (ASM/height(2), ASM/weight, and ASM/BMI), isometric knee extension, arm flexion and handgrip strength, maximal inspiratory and expiratory pressures, and gait speed pre- and postintervention. Trained groups participated in a 12-week program and improved in maximum static inspiratory pressure, maximum static expiratory pressure, knee extension, and arm flexion (p < .05), whereas nonsignificant changes were found in gait speed and ASM indexes pre-and postintervention in the three groups. In conclusion, resistance training improved skeletal muscle strength in the studied population, and any ASM index was found to be appropriate for detecting changes after physical interventions.This study was supported by Universitat de Valencia (UV-INV-AE14-269704) and has no conflict of interest to declare.Cebriá, M.; Balasch-Bernat, M.; Tortosa, M.; Balasch Parisi, S. (2018). Effects of Resistance Training of Peripheral Muscles Versus Respiratory Muscles in Older Adults With Sarcopenia Who are Institutionalized: A Randomized Controlled Trial. Journal of Aging and Physical Activity. 26(4):637-646. https://doi.org/10.1123/japa.2017-0268S63764626

    The ocean sampling day consortium

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    Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits

    Liver segmentation in MRI: a fully automatic method based on stochastic partitions

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    There are few fully automated methods for liver segmentation in magnetic resonance images (MRI) despite the benefits of this type of acquisition in comparison to other radiology techniques such as computed tomography (CT). Motivated by medical requirements, liver segmentation in MRI has been carried out. For this purpose, we present a new method for liver segmentation based on the watershed transform and stochastic partitions. The classical watershed over-segmentation is reduced using a marker-controlled algorithm. To improve accuracy of selected contours, the gradient of the original image is successfully enhanced by applying a new variant of stochastic watershed. Moreover, a final classifier is performed in order to obtain the final liver mask. Optimal parameters of the method are tuned using a training dataset and then they are applied to the rest of studies (17 datasets). The obtained results (a Jaccard coefficient of 0.91 +/- 0.02) in comparison to other methods demonstrate that the new variant of stochastic watershed is a robust tool for automatic segmentation of the liver in MRI. (C) 2014 Elsevier Ireland Ltd. All rights reserved.This work has been supported by the MITYC under the project NaRALap (ref. TSI-020100-2009-189), partially by the CDTI under the project ONCOTIC (IDI-20101153), by Ministerio de Educacion y Ciencia Spain, Project Game Teen (TIN2010-20187) projects Consolider-C (SEJ2006-14301/PSIC), "CIBER of Physiopathology of Obesity and Nutrition, an initiative of ISCIII" and Excellence Research Program PROMETEO (Generalitat Valenciana. Conselleria de Educacion, 2008-157). We would like to express our gratitude to the Hospital Clinica Benidorm, for providing the MR datasets and to the radiologist team of Inscanner for the manual segmentation of the MR images.López-Mir, F.; Naranjo Ornedo, V.; Angulo, J.; Alcañiz Raya, ML.; Luna, L. (2014). Liver segmentation in MRI: a fully automatic method based on stochastic partitions. Computer Methods and Programs in Biomedicine. 114(1):11-28. https://doi.org/10.1016/j.cmpb.2013.12.022S1128114

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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