119 research outputs found
High precision frequency estimation for harpsichord tuning classification
We present a novel music signal processing task of classifying the tuning of a harpsichord from audio recordings of standard musical works. We report the results of a classification experiment involving six different temperaments, using real harpsichord recordings as well as synthesised audio data. We introduce the concept of conservative transcription, and show that existing high-precision pitch estimation techniques are sufficient for our task if combined with conservative transcription. In particular, using the CQIFFT algorithm with conservative transcription and removal of short duration notes, we are able to distinguish between 6 different temperaments of harpsichord recordings with 96% accuracy (100% for synthetic data)
Publishing Music Similarity Features on the Semantic Web.
We describe the process of collecting, organising and publishing a large set of music similarity features produced by the SoundBite [10] playlist generator tool. These data can be a valuable asset in the development and evaluation
of new Music Information Retrieval algorithms. They can also be used in Web-based music search and retrieval applications. For this reason, we make a database of features available on the Semantic Web via a SPARQL end-point,
which can be used in Linked Data services. We provide examples of using the data in a research tool, as well as in a simple web application which responds to audio queries and finds a set of similar tracks in our database
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Visualising Chord Progressions in Music Collections: A Big Data Approach
In the Digital Music Lab project we work on the automatic analysis of large audio databases that results in rich annotations for large corpora of music. The musicological interpretation of this data from thousands of pieces is a challenging task that can beneο¬t greatly from speciο¬cally designed interactive visualisation. Most existing big music data visualisation focuses on cultural attributes, mood, or listener behaviour.
In this ongoing work we explore chord sequence patterns extracted by sequential pattern mining of more than one million tracks from the I Like Music commercial music collection. We present here several new visual representations that summarise chord patterns according to chord types, chroma, pattern structure and support, enabling musicologists to develop and answer questions about chord patterns in music collections.
Our visualisations represent root movement and chord qualities mostly in a geometrical way and use colour to represent pattern support. We use two individually conο¬gurable views in parallel to encourage comparisons, either between different representations of one corpus, highlighting complimentary musical aspects, or between different datasets,here representing different genres. We adapt several visualisation techniques to chord pattern sets using some novel layouts to support musicologists with their exploration and interpretation of the corpora. We found that differences between chord patterns of different genres, e.g. Rock & Roll vs. Jazz, are visible and can be used to generate hypotheses for the study of individual pieces, further statistical investigations or new data processing and visualisation. Our designs will be adapted as user needs are established through ongoing work. Means of aggregating, focusing and ο¬ltering by selected characteristics (such as key,melodic patterns etc.) will be added as we develop our design for the visualisation of chord patterns in close collaboration with musicologists
Integrating BDI agents with Agent-based simulation platforms
Agent-Based Models (ABMs) is increasingly being used for exploring and supporting decision making about social science scenarios involving modelling of human agents. However existing agent-based simulation platforms (e.g., SWARM, Repast) provide limited support for the simulation of more complex cognitive agents required by such scenarios. We present a framework that allows Belief-Desire Intention (BDI) cognitive agents to be embedded in an ABM system. Architecturally, this means that the "brains" of an agent can be modelled in the BDI system in the usual way, while the "body" exists in the ABM system. The architecture is exible in that the ABM can still have non-BDI agents in the simulation, and the BDI-side can have agents that do not have a physical counterpart (such as an organisation). The framework addresses a key integration challenge of coupling event-based BDI systems, with time-stepped ABM systems. Our framework is modular and supports integration off-the-shelf BDI systems with off-the-shelf ABM systems. The framework is Open Source, and all integrations and applications are available for use by the modelling community
Crystal Structure of Outer Membrane Protein NMB0315 from Neisseria meningitidis
NMB0315 is an outer membrane protein of Neisseria meningitidis serogroup B (NMB) and a potential candidate for a broad-spectrum vaccine against meningococcal disease. The crystal structure of NMB0315 was solved by single-wavelength anomalous dispersion (SAD) at a resolution of 2.4 Γ
and revealed to be a lysostaphin-type peptidase of the M23 metallopeptidase family. The overall structure consists of three well-separated domains and has no similarity to any previously published structure. However, only the topology of the carboxyl-terminal domain is highly conserved among members of this family, and this domain is a zinc-dependent catalytic unit. The amino-terminal domain of the structure blocks the substrate binding pocket in the carboxyl-terminal domain, indicating that the wild-type full-length protein is in an inactive conformational state. Our studies improve the understanding of the catalytic mechanism of M23 metallopeptidases
Pericyte Migration: A Novel Mechanism of Pericyte Loss in Experimental Diabetic Retinopathy
OBJECTIVEβ The mechanism underlying pericyte loss during incipient diabetic retinopathy remains controversial. Hyperglycemia induces angiopoietin-2 (Ang-2) transcription, which modulates capillary pericyte coverage. In this study, we assessed loss of pericyte subgroups and the contribution of Ang-2 to pericyte migration
Pinhole-free perovskite films for efficient solar modules
We report on a perovskite solar module with an aperture area of 4 cm2 and geometrical fill factor of 91%. The module exhibits an aperture area power conversion efficiency (PCE) of 13.6% from a currentβvoltage scan and 12.6% after 5 min of maximum power point tracking. High PCE originates in pinhole-free perovskite films made with a precursor combination of Pb(CH3CO2)2Β·3H2O, PbCl2, and CH3NH3I
The NlpD Lipoprotein Is a Novel Yersinia pestis Virulence Factor Essential for the Development of Plague
Yersinia pestis is the causative agent of plague. Previously we have isolated an attenuated Y. pestis transposon insertion mutant in which the pcm gene was disrupted. In the present study, we investigated the expression and the role of pcm locus genes in Y. pestis pathogenesis using a set of isogenic surE, pcm, nlpD and rpoS mutants of the fully virulent Kimberley53 strain. We show that in Y. pestis, nlpD expression is controlled from elements residing within the upstream genes surE and pcm. The NlpD lipoprotein is the only factor encoded from the pcm locus that is essential for Y. pestis virulence. A chromosomal deletion of the nlpD gene sequence resulted in a drastic reduction in virulence to an LD50 of at least 107 cfu for subcutaneous and airway routes of infection. The mutant was unable to colonize mouse organs following infection. The filamented morphology of the nlpD mutant indicates that NlpD is involved in cell separation; however, deletion of nlpD did not affect in vitro growth rate. Trans-complementation experiments with the Y. pestis nlpD gene restored virulence and all other phenotypic defects. Finally, we demonstrated that subcutaneous administration of the nlpD mutant could protect animals against bubonic and primary pneumonic plague. Taken together, these results demonstrate that Y. pestis NlpD is a novel virulence factor essential for the development of bubonic and pneumonic plague. Further, the nlpD mutant is superior to the EV76 prototype live vaccine strain in immunogenicity and in conferring effective protective immunity. Thus it could serve as a basis for a very potent live vaccine against bubonic and pneumonic plague
Bacteriophage-Resistant Mutants in Yersinia pestis: Identification of Phage Receptors and Attenuation for Mice
Background: Bacteriophages specific for Yersinia pestis are routinely used for plague diagnostics and could be an alternative to antibiotics in case of drug-resistant plague. A major concern of bacteriophage therapy is the emergence of phageresistant mutants. The use of phage cocktails can overcome this problem but only if the phages exploit different receptors. Some phage-resistant mutants lose virulence and therefore should not complicate bacteriophage therapy. Methodology/Principal Findings: The purpose of this work was to identify Y. pestis phage receptors using site-directed mutagenesis and trans-complementation and to determine potential attenuation of phage-resistant mutants for mice. Six receptors for eight phages were found in different parts of the lipopolysaccharide (LPS) inner and outer core. The receptor for R phage was localized beyond the LPS core. Most spontaneous and defined phage-resistant mutants of Y. pestis were attenuated, showing increase in LD 50 and time to death. The loss of different LPS core biosynthesis enzymes resulted in the reduction of Y. pestis virulence and there was a correlation between the degree of core truncation and the impact on virulence. The yrbH and waaA mutants completely lost their virulence. Conclusions/Significance: We identified Y. pestis receptors for eight bacteriophages. Nine phages together use at least seven different Y. pestis receptors that makes some of them promising for formulation of plague therapeutic cocktails. Most phage-resistant Y. pestis mutants become attenuated and thus should not pose a serious problem for bacteriophag
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