Measuring temperature - dependent propagating disturbances in coronal fan loops using multiple SDO/AIA channels and surfing transform technique

A set of co-aligned high resolution images from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) is used to investigate propagating disturbances (PDs) in warm fan loops at the periphery of a non-flaring active region NOAA AR 11082. To measure PD speeds at multiple coronal temperatures, a new data analysis methodology is proposed enabling quantitative description of subvisual coronal motions with low signal-to-noise ratios of the order of 0.1 %. The technique operates with a set of one-dimensional "surfing" signals extracted from position-time plots of several AIA channels through a modified version of Radon transform. The signals are used to evaluate a two-dimensional power spectral density distribution in the frequency - velocity space which exhibits a resonance in the presence of quasi-periodic PDs. By applying this analysis to the same fan loop structures observed in several AIA channels, we found that the traveling velocity of PDs increases with the temperature of the coronal plasma following the square root dependence predicted for the slow mode magneto-acoustic wave which seems to be the dominating wave mode in the studied loop structures. This result extends recent observations by Kiddie et al. (Solar Phys., 2012) to a more general class of fan loop systems not associated with sunspots and demonstrating consistent slow mode activity in up to four AIA channels.Comment: 23 pages, 8 figures, 2 table

Models and Analysis of Vocal Emissions for Biomedical Applications

The International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications (MAVEBA) came into being in 1999 from the particularly felt need of sharing know-how, objectives and results between areas that until then seemed quite distinct such as bioengineering, medicine and singing. MAVEBA deals with all aspects concerning the study of the human voice with applications ranging from the neonate to the adult and elderly. Over the years the initial issues have grown and spread also in other aspects of research such as occupational voice disorders, neurology, rehabilitation, image and video analysis. MAVEBA takes place every two years always in Firenze, Italy

Non-invasive vascular assessment using photoplethysmography

Photoplethysmography (PPG) has become widely accepted as a valuable clinical tool for performing non-invasive biomedical monitoring. The dominant clinical application of PPG has been pulse oximetry, which uses spectral analysis of the peripheral blood supply to establish haemoglobin saturation. PPG has also found success in screening for venous dysfunction, though to a limited degree. Arterial Disease (AD) is a condition where blood flow in the arteries of the body is reduced,a condition known as ischaernia. Ischaernia can result in pain in the affected areas, such as chest pain for an ischearnic heart, but does not always produce symptoms. The most common form of AD is arteriosclerosis, which affects around 5% of the population over 50 years old. Arteriosclerosis, more commonly known as 'hardening of the arteries' is a condition that results in a gradual thickening, hardening and loss of elasticity in the walls of the arteries, reducing overall blood flow. This thesis investigates the possibility of employing PPG to perform vascular assessment, specifically arterial assessment, in two ways. PPG based perfusion monitoring may allow identification of ischaernia in the periphery. To further investigate this premise, prospective experimental trials are performed, firstly to assess the viability of PPG based perfusion monitoring and culminating in the development of a more objective method for determining ABPI using PPG based vascular assessment. A complex interaction between the heart and the connective vasculature, detected at the measuring site, generates the PPG signal. The haemodynamic properties of the vasculature will affect the shape of the PPG waveform, characterising the PPG signal with the properties of the intermediary vasculature. This thesis investigates the feasibility of deriving quantitative vascular parameters from the PPG signal. A quantitative approach allows direct identification of pathology, simplifying vascular assessment. Both forward and inverse models are developed in order to investigate this topic. Application of the models in prospective experimental trials with both normal subjects and subjects suffering PVD have shown encouraging results. It is concluded that the PPG signal contains information on the connective vasculature of the subject. PPG may be used to perform vascular assessment using either perfusion based techniques, where the magnitude of the PPG signal is of interest, or by directly assessing the connective vasculature using PPG, where the shape of the PPG signal is of interest. it is argued that PPG perfusion based techniques for performing the ABPI diagnosis protocol can offer greater sensitivity to the onset of PAD, compared to more conventional methods. It is speculated that the PPG based ABPI diagnosis protocol could provide enhanced PAD diagnosis, detecting the onset of the disease and allowing a treatmenpt lan to be formed soonert han was possible previously. The determination of quantitative vascular parameters using PPG shape could allow direct vascular diagnosis, reducing subjectivity due to interpretation. The prospective trials investigating PPG shape analysis concentrated on PVD diagnosis, but it is speculated that quantitative PPG shaped based vascular assessment could be a powerful tool in the diagnosis of many vascular based pathological conditions

Reliability of Subjective Endoscopic Parameters in the Differentiation of Essential Voice Tremor and Adductor Spasmodic Dysphonia Using High-Speed Videoendoscopy

Certain neurogenic voice disorders present with similar or overlapping audio perceptual voice characteristics. Developing reliable and standardized perceptual measures of vocal fold vibratory characteristics for such voice disorders can enable accurate diagnosis and lead to faster, targeted treatment. In this study, subjective perceptual vocal fold vibratory characteristics and the presence and absence of supraglottic events during phonation were investigated to differentiate between Adductor Spasmodic Dysphonia (ADSD) and Essential Vocal Fold Tremor (EVT) using high-speed videoendoscopy (HSV). The specific aims of the study were to 1) assess which subjective endoscopic vocal fold vibratory measures differentiate EVT from AdSD; and 2) assess the inter-rater and intra-rater reliability of the ratings. High speed video recordings of vibratory vocal fold motion were selected to conduct a retrospective analysis on existing data. The participants were classified into three groups: 16 participants with a diagnosis of Adductor Spasmodic Dysphonia, 8 participants with a clinical diagnosis of Essential Vocal Tremor, and 10 participants with a diagnosis of Both (AdSD with Tremor). The inclusion criteria for HSV data was the presence of a full view of true vocal folds and supraglottic structures during vibration. It was hypothesized that HSV vocal fold vibratory measures and supraglottic events would distinguish EVT and ADSD and these measures would be reliable. In addition, the vocal fold vibratory features would be more reliable than supraglottic events in differentiating between the groups. Results demonstrated mixed reliability for supraglottic and vocal fold vibratory parameters. None of the hypothesized supraglottic parameters demonstrated any significant distinction between diagnostic groups given the three raters’ responses. While all four vocal fold vibratory parameters revealed distinctive patterns between the three diagnostic categories, only two, right/left TVF symmetry and anterior/posterior TVF symmetry, met the requirements for both reliability and differentiation. For these parameters, EVT demonstrated greater vocal fold symmetry in comparison to AdSD; however, those with a differential diagnosis of both demonstrated the highest vocal fold symmetry

Models and analysis of vocal emissions for biomedical applications

This book of Proceedings collects the papers presented at the 3rd International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications, MAVEBA 2003, held 10-12 December 2003, Firenze, Italy. The workshop is organised every two years, and aims to stimulate contacts between specialists active in research and industrial developments, in the area of voice analysis for biomedical applications. The scope of the Workshop includes all aspects of voice modelling and analysis, ranging from fundamental research to all kinds of biomedical applications and related established and advanced technologies