1,721,011 research outputs found
Triad’s consonance and dissonance: combining roughness and compactness models
No full textTheories of consonance and dissonance based on the “roughness” approach are those that explain these perceptions as due to the primary beatings between harmonics. Originally proposed by Helmholtz, this approach has been very popular in the last century, being naturally associated to continuous functions of the frequency ratios, on the contrary of theories based on the “compactness” approach. In a previous work, we focused on the roughness consonance and dissonance indicators for dyads, showing the importance of including weight functions and especially secondary beatings. Here, we generalize the roughness indicators to describe the consonance and dissonance for triads. We compare our model predictions with perceptual data from a recent psychoacoustic test by means of a Chi-square analysis. The result is that roughness indicators provide a quite effective, but not fully satisfactory, description of consonance and dissonance for triads. We then study the effect of combining roughness and compactness models for triads: in this case, a very satisfactory agreement with perceptual data is achieved
Segmentation procedure for the generation of a 3D model and solid replica of a human skull
Get PDFThe present study describes a strategy to produce patient-specific skull base rep-lica with realistic shapes, starting from radiological images. Several papers aim to highlight the clinical value of patient-specific three-dimensional (3D) models, ob-tained segmenting multidetector computed tomography (MDCT) images, for preoper-ative planning in general surgery, for physician training and for didactics targets.
In this study, segmentation and 3D model generation were performed using a semiautomatic tool developed in the EndoCAS centre. The segmentation procedure is based on the neighbourhood connected region-growing algorithm that, appropri-ately parameterized for the anatomy of interest and combined with the optimal seg-mentation sequence, generates good-quality 3D images coupled with facility of use. Using a touch screen monitor, manual refining has been added to segment struc-tures unsuitable for automatic reconstruction.
The goal of the present work consists in providing and visualizing quantitative geometrical and topological information on the anatomy of a cranium, starting from a MDCT dataset, and to develop a detailed solid replica that allow to improve the com-prehension of anatomy and the dimensions of deep structures of a skull base. Ana-tomical structures of little size - e.g. foramen rotundum, foramen spinosum, lamina cribriformis, hypoglossal canal - were replicated in detail. Furthermore our 3D virtual model permits to well distinguish pneumatized bones; in particular nasal cavities and paranasal sinuses were minutely computer-generated.
We consider that our methodological approach to reproduce virtual and solid an-atomical models can represent an useful didactic tool, both for undergraduate and postgraduate students
Rapid prototyping of cerebral arteries: a perfect scenario to develop innovative endovascular devices
No full textAbstract not availabl
An integrated platform for an effective liver surgical planning through segmentation of multiphase CT datasets
No full textAbstract not availabl
Assessment of DICOM Viewers Capable of Loading Patient-specific 3D Models Obtained by Different Segmentation Platforms in the Operating Room
No full textPatient-specific 3D models obtained by the segmentation of volumetric diagnostic images play an increasingly important role in surgical planning. Surgeons use the virtual models reconstructed through segmentation to plan challenging surgeries. Many solutions exist for the different anatomical districts and surgical interventions. The possibility to bring the 3D virtual reconstructions with native radiological images in the operating room is essential for fostering the use of intraoperative planning. To the best of our knowledge, current DICOM viewers are not able to simultaneously connect to the picture archiving and communication system (PACS) and import 3D models generated by external platforms to allow a straight integration in the operating room. A total of 26 DICOM viewers were evaluated: 22 open source and four commercial. Two DICOM viewers can connect to PACS and import segmentations achieved by other applications: Synapse 3D® by Fujifilm and OsiriX by University of Geneva. We developed a software network that converts diffuse visual tool kit (VTK) format 3D model segmentations, obtained by any software platform, to a DICOM format that can be displayed using OsiriX or Synapse 3D. Both OsiriX and Synapse 3D were suitable for our purposes and had comparable performance. Although Synapse 3D loads native images and segmentations faster, the main benefits of OsiriX are its user-friendly loading of elaborated images and it being both free of charge and open source
Pathological and histological findings associated with the feline lungworm Troglostrongylus brevior
No full textTroglostrongylus brevior is a neglected feline lungworm species, which has been increasingly reported in the Mediterranean area, although scant data are available on the respiratory alterations it causes in cats. Therefore, we describe the gross and histological lesions of a 20-week old kitten that succumbed due to the onset of a fulminant respiratory failure. At necropsy, a catarrhal exudate was observed in the airways, along with nematodes in the trachea and bronchi. The lungs were processed for histological examination and serial pulmonary sections were performed. A total of 14 nematodes were collected, being all morphologically and molecularly identified as T. brevior. Lungworms were histologically localized within the bronchial lumen, surrounded by an eosinophilic infiltrate. The presence of T. brevior in the airways has been histologically documented for the first time and its life-threatening potential is discussed
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Peer-To-Peer Architectures in Distributed Data Management Systems for Large Hadron Collider Experiments
No full textThe main goal of the presented research is to investigate Peer-to-Peer architectures and to leverage distributed services to support networked autonomous systems. The research work focuses on development and demonstration of technologies suitable for providing autonomy and flexibility in the context of distributed network management and distributed data acquisition. A network management system enables the network administrator to monitor a computer network and properly handle any failure that can arise within the network. An online data acquisition (DAQ) system for high-energy physics experiments has to collect, combine, filter, and store for later analysis a huge amount of data, describing subatomic particles collision events. Both domains have tight constraints which are discussed and tackled in this work. New emerging paradigms have been investigated to design novel middleware architectures for such distributed systems, particularly the Active Networks paradigm and the Peer-to-Peer paradigm. A network management framework has been designed and developed, which is able to carry on network management tasks and failures detection. Moreover an Artificial Intelligence based autonomous agent has been prototyped, in order to support the network administrator in pursuing his management responsibilities. The Active Networks paradigm has been used in this context to enable network programming. In addition, a software prototype has been developed to enable controlling of DAQ systems by means of distributed discovery services. A discovery service allows network entities to be acknowledged about each other, and enables them to expose and make use of custom services. The Peer-to-Peer paradigm has been leveraged to implement a discovery service to ease configuration and monitoring of distributed DAQ systems. The research and development activity carried on in both domains had the common goal of demonstrating how appropriate middleware can provide the required autonomy to systems under analysis
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