Comparison of time- and frequency-domain based LF-model fitting methods for voice source parametrisation

The Liljencrants-Fant (LF) model is used to capture the shape parameters from the voice source. In this paper, two LF-model fitting approaches (one time-domain, one frequency-domain) are presented and compared by applying each to artificial and real speech source signals. Experimental results demonstrate that in most cases the time-domain method is superior to the frequency-domain based algorithm. By assessing approaches for estimating the LF-model parameters from a glottal source signal, this paper makes a contribution to the investigation of voice source parametrisation

LF model based glottal source parameter estimation by extended Kalman filtering

A new algorithm for glottal source parameter estimation of voiced speech based on the Liljencrants-Fant (LF) model is presented in this work. Each pitch period of the inverse filtered glottal flow derivative is divided into two phases according to the glottal closing instant and an extended Kalman filter is iteratively applied to estimate the shape controlling parameters for both phases. By searching the minimal mean square error between the reconstructed LF pulse and the original signal, an optimal set of estimates can be obtained. Preliminary experimental results show that the proposed algorithm is effective for a wide range of LF parameters for different voice qualities with different noise levels, and accuracy especially for estimation of return phase parameters compares better than standard time-domain fitting methods while requiring a significantly lower computational load

Robust tracking of glottal LF-model parameters by multi-estimate fusion

A new approach to robust tracking of glottal LF-model parameters is presented. The approach does not rely on a new glottal source estimation algorithm, but instead introduces a new extensible multi-estimate fusion framework. Within this framework several existing algorithms are applied in parallel to extract glottal LF-model parameter estimates which are subsequently passed to quantitative data fusion procedures. The preliminary implementation of the fusion algorithm described here incorporates three glottal inverse filtering methods and one time-domain LF-model fitting algorithm. Experimental results for both synthetic and natural speech signals demonstrate the effectiveness of the fusion algorithm. The proposed method is flexible and can be easily extended for other speech processing applications such as speech synthesis, speaker identification and prosody analysis

Automatic LF-model fitting to the glottal source waveform by extended Kalman filtering

A new method for automatically fitting the Liljencrants-Fant (LF) model to the time domain waveform of the glottal flow derivative is presented in this paper. By applying an extended Kalman filter (EKF) to track the LF-model shape-controlling parameters and dynamically searching for a globally minimal fitting error, the algorithm can accurately fit the LF-model to the inverse filtered glottal flow derivative. Experimental results show that the method has better performance for both synthetic and real speech signals compared to a standard time-domain LF-model fitting algorithm. By offering a new method to estimate the glottal source LF-model parameters, the proposed algorithm can be utilised in many applications

The impact of assuming the primary caregiver role following traumatic spinal cord injury: an interpretative phenomenological analysis of the spouse's experience.

This study aimed to explore the lived experience of assuming the primary caregiver role in a group of spouses of individuals living with a traumatic spinal cord injury (SCI) (injuries ranged from paraplegia to quadriplegia). Individual in-depth interviews were conducted with 11 participants who were both the spouse and primary caregiver of an individual with a SCI; of these, 10 were female and 1 was male. All interviews were transcribed verbatim and were subjected to interpretative phenomenological analysis (IPA). Here we present three inter-related master themes: 'The emotional impact of SCI'; 'Post-injury shift in relationship dynamics' and 'Impact of caregiving on identity'. Regarding the emotional impact of spinal injury, participants reported an almost instantaneous sense of loss, emptiness and grief during the injured person's rehabilitative period and feelings of anxiety were reported in anticipation of their return to the family home. A distinct change in role from spouse and lover to care provider was reported and this ultimately contributed to relationship change and a loss of former identity. The findings are discussed in relation to extant caregiver literature and recommendations for future caregiver support are highlighte

Methicillin-resistant Staphylococcus aureus Clones, Western Australia

The emergence of multiple multidrug-resistant Panton-Valentine leukocidin–positive MRSA clones in the community is a major public health concern

L&D professionals in organisations: much ambition, unfilled promise

This monograph reports a study investigating the roles of learning and development (L&D) professionals in Irish, UK European and US organisations. The study investigates the contextual factors influencing L&D roles in organisations, the strategic and operational roles that L&D professionals play in organisations, the competencies and career trajectories of L&D professionals, the perceptions of multiple internal stakeholders of the effectiveness of L&D and the relationships between context, L&D roles, competencies/expertise, and perceived effectiveness. We gathered data using multiple methods: survey (n=440), Delphi study (n=125) and semi-structured interviews (n=30). The analysis revealed that L&D professionals increasingly respond to a multiplicity of external and internal contextual influences and internal stakeholders perceived the effectiveness of L&D professionals differently with significant gaps in perceptions of what L&D contributes to organisational effectiveness. L&D professionals perform both strategic and operational roles in organisations and they progress through four career levels. Each L&D role and career level requires a distinct and unique set of foundational competencies and L&D expertise. Finally, we found that different contextual predictors were important in explaining the perceived effectiveness of L&D roles and the importance attached to different foundational competencies and areas of L&D expertise. We discuss the implications for theory, research and practice

Continuing versus stopping prestroke antihypertensive therapy in acute intracerebral hemorrhage: a subgroup analysis of the efficacy of nitric oxide in stroke trial

Background and purpose: More than 50% of patients with acute intracerebral haemorrhage (ICH) are taking antihypertensive drugs before ictus. Although antihypertensive therapy should be given long term for secondary prevention, whether to continue or stop such treatment during the acute phase of ICH remains unclear, a question that was addressed in the Efficacy of Nitric Oxide in Stroke (ENOS) trial. Methods: ENOS was an international multicenter, prospective, randomized, blinded endpoint trial. Among 629 patients with ICH and systolic blood pressure between 140 and 220 mmHg, 246 patients who were taking antihypertensive drugs were assigned to continue (n = 119) or to stop (n = 127) taking drugs temporarily for 7 days. The primary outcome was the modified Rankin Score at 90 days. Secondary outcomes included death, length of stay in hospital, discharge destination, activities of daily living, mood, cognition, and quality of life. Results: Blood pressure level (baseline 171/92 mmHg) fell in both groups but was significantly lower at 7 days in those patients assigned to continue antihypertensive drugs (difference 9.4/3.5 mmHg, P < .01). At 90 days, the primary outcome did not differ between the groups; the adjusted common odds ratio (OR) for worse outcome with continue versus stop drugs was .92 (95% confidence interval, .45- 1.89; P = .83). There was no difference between the treatment groups for any secondary outcome measure, or rates of death or serious adverse events. Conclusions: Among patients with acute ICH, immediate continuation of antihypertensive drugs during the first week did not reduce death or major disability in comparison to stopping treatment temporarily

Increased peri-ductal collagen micro-organization may contribute to raised mammographic density

BACKGROUND: High mammographic density is a therapeutically modifiable risk factor for breast cancer. Although mammographic density is correlated with the relative abundance of collagen-rich fibroglandular tissue, the causative mechanisms, associated structural remodelling and mechanical consequences remain poorly defined. In this study we have developed a new collaborative bedside-to-bench workflow to determine the relationship between mammographic density, collagen abundance and alignment, tissue stiffness and the expression of extracellular matrix organising proteins. METHODS: Mammographic density was assessed in 22 post-menopausal women (aged 54–66 y). A radiologist and a pathologist identified and excised regions of elevated non-cancerous X-ray density prior to laboratory characterization. Collagen abundance was determined by both Masson’s trichrome and Picrosirius red staining (which enhances collagen birefringence when viewed under polarised light). The structural specificity of these collagen visualisation methods was determined by comparing the relative birefringence and ultrastructure (visualised by atomic force microscopy) of unaligned collagen I fibrils in reconstituted gels with the highly aligned collagen fibrils in rat tail tendon. Localised collagen fibril organisation and stiffness was also evaluated in tissue sections by atomic force microscopy/spectroscopy and the abundance of key extracellular proteins was assessed using mass spectrometry. RESULTS: Mammographic density was positively correlated with the abundance of aligned periductal fibrils rather than with the abundance of amorphous collagen. Compared with matched tissue resected from the breasts of low mammographic density patients, the highly birefringent tissue in mammographically dense breasts was both significantly stiffer and characterised by large (>80 μm long) fibrillar collagen bundles. Subsequent proteomic analyses not only confirmed the absence of collagen fibrosis in high mammographic density tissue, but additionally identified the up-regulation of periostin and collagen XVI (regulators of collagen fibril structure and architecture) as potential mediators of localised mechanical stiffness. CONCLUSIONS: These preliminary data suggest that remodelling, and hence stiffening, of the existing stromal collagen microarchitecture promotes high mammographic density within the breast. In turn, this aberrant mechanical environment may trigger neoplasia-associated mechanotransduction pathways within the epithelial cell population. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13058-015-0664-2) contains supplementary material, which is available to authorized users