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INTERSPEECH 2021
No full textMany of the commonly used voice source models are based on piecewise elementary functions defined in the time domain.
The discrete-time implementation of such models generally causes aliasing distortion, which make them less useful for certain applications. This paper presents a method which eliminates this distortion. The key component of the proposed method is the frequency domain description of the source model. By deploying the Laplace transform and phasor arithmetic, closed-form expressions of the source model spectrum can be derived. This facilitates the calculation of the spectrum directly from the model parameters, which in turn makes it possible to obtain the ideal discrete spectrum of the model given the sampling frequency used. This discrete spectrum is entirely free of aliasing distortion, and the inverse discrete Fourier transform is used to compute the sampled glottal flow pulse. The proposed method was applied to the widely used LF model, and the complete Laplace transform of the model is
presented. Also included are closed-form expressions of the amplitude spectrum and the phase spectrum for the calculation of the LF model spectrum
Calibrating COVID-19 susceptible-exposed-infected-removed models with time-varying effective contact rates
No full textWe describe the population-based susceptible-exposed-infected-removed (SEIR) model developed by the Irish Epidemiological Modelling Advisory Group (IEMAG), which advises the Irish government on COVID-19 responses. The model assumes a time-varying effective contact rate (equivalently, a time-varying reproduction number) to model the effect of non-pharmaceutical interventions. A crucial technical challenge in applying such models is their accurate calibration to observed data, e.g. to the daily number of confirmed new cases, as the history of the disease strongly affects predictions of future scenarios. We demonstrate an approach based on inversion of the SEIR equations in conjunction
with statistical modelling and spline-fitting of the data to produce a robust methodology for
calibration of a wide class of models of this type. This article is part of the theme issue ‘Data science approaches to infectious disease surveillance’
Block Copolymer Thin Films: Self-Assembly of Large Molecular Weight Systems and the Fabrication of Novel Metal/Metal Oxide Nanomaterials
No full textThe self-assembly of block copolymers (BCPs) is considered an excellent candidate to further
the development and progression of nanoscale technologies. While lithographic applications
remain a primary topic of focus for BCP research, less conventional areas of interest such as
optics, catalysis, and sensing present unique challenges to the field. In the case of these
aforementioned areas, the advantages of BCP-templated nanostructures include low cost, high
scalability, morphological tunability, and large-area ordering. This thesis reports the
development of an innovative strategy for the self-assembly of large BCP systems with optics-
scale dimensionality, along with expanding the potential of BCP templating via fabricating
novel catalytic and sensing materials. Firstly, the rapid self-assembly of a large BCP system
(poly(styrene)-b-poly-2-vinylpyridine (PS-b-P2VP)) into lamellar domains via a controlled
solvent vapour annealing (SVA) strategy is detailed. The influence of variables such as the film
thickness, SVA time and the rate of swelling on the morphology of the BCP system are
analysed. A liquid phase infiltration (LPI) strategy is utilised to convert the lamellar BCP films
into a metal oxide hardmask, which is then etched into a Si substrate to create large period
nanowall features. The resulting self-assembled BCP films are also utilised for synthesizing 3-
dimensional metallic lamellae, again using a LPI strategy. The relationship between the BCP
film thickness on the heights of the metal structures is detailed, enabling precise control over
the heights of the nanowall structures. These structures are utilised as photocatalytic structures
for the degradation of methyl orange, revealing a height-dependent performance relationship.
Finally, a novel, multifunctional catalytic device is fabricated and characterised using BCP
templating. A PS-b-P4VP BCP system is self-assembled into cylindrical domains on an
indium-tin oxide (ITO) substrate via SVA, which is then converted into WO3 nanowires using
a LPI strategy. The device is successfully utilised for both water oxidation and highly selective
epinephrine detection
Carbon pricing ethics
No full textThe three main types of policies for addressing climate change are command and control regulation, carbon taxes (or price instruments), and cap and trade (or quantity instruments). The first question in the ethics of carbon pricing is whether the latter two (price and quantity instruments) are preferable to command and control regulation. The second question is, if so, how should we evaluate the relative merits of price and quantity instruments. I canvass relevant arguments to explain different ways of addressing these important policy questions, suggesting that carbon pricing is preferable to command and control regulation, and that price instruments have the theoretical edge over quantity instruments
Designing information systems to break habits and promote preventive behaviours during large-scale disease outbreaks
No full textAdhering to preventive behaviours, like social distancing and wearing a mask, can help reduce the spread of some transmissible diseases; however, doing so can be a challenge as it requires people to break established habits. This challenge will be most evident for organisations as they need to ensure that all stakeholders adhere to preventive behaviours to resume in-person business operations. While various information systems (IS) have emerged to address this challenge, they remain limited in scope and fall short of helping users navigate the evolving practices and guidelines of a pandemic. To address this shortcoming, we adopt the design science research approach to derive design principles for IS supporting the breaking of established habits and promotion of preventive behaviours. The design principles are rigorously anchored in the habit alteration knowledge base and the Health Belief Model. We demonstrate how the design principles can be applied using an illustrative case
Assessing Patient-Specific Microwave Breast Imaging in Clinical Case Studies
No full textMicrowave breast imaging has seen increasing use in clinical investigations in the past decade with over eight systems having being trialled with patients. The majority of systems use radar-based algorithms to reconstruct the image shown to the clinician which requires an estimate of the dielectric properties of the breast to synthetically focus signals to reconstruct the image. Both simulated and experimental studies have shown that, even in simplified scenarios,
misestimation of the dielectric properties can impair both the image quality and tumour detection. Many methods have been proposed to address the issue of the estimation of dielectric properties, but few have been tested with patient images. In this work, a leading approach for dielectric properties estimation based on the computation of many candidate images for microwave breast imaging is analysed with patient images for the first time. Using five clinical case studies of both healthy breasts and breasts with abnormalities, the advantages and disadvantages of computational patient-specific microwave breast image reconstruction are highlighted
Effects on an acute priming exercise and high-intensity interval training on oxygen uptake and muscle deoxygenation kinetics in older individuals with type 2 diabetes
No full textPeak oxygen uptake (V̇O2peak) is consistently reduced in individuals with type 2 diabetes (T2D) of all ages compared with non-diabetic (ND) controls. In middle-aged (between 45 to 60 y) individuals with T2D these reductions in V̇O2peak are influenced by a reduced rate of microvascular blood flow adaptations, but it is unknown if these vascular impairments are apparent in older individuals with this disease. In addition, the dynamic response of V̇O2 at the onset of moderate-intensity exercise (V̇O2 kinetics) is blunted (i.e. slowed) in middle-aged, but not older (between 60 to 70 y) people with T2D compared with age-matched corresponding ND controls. This is likely due to the powerful deleterious effect of ageing per se mainly in untrained individuals. Understanding how to ameliorate these impairments and the confounding effects of older age is important given that these limitations may lead to cardiovascular complications and all-cause mortality.
In this regard, an acute bout of heavy-intensity priming exercise (PE) as well as short-term training interventions involving moderate-intensity continuous training (MICT) and/or low-volume high-intensity interval training (HIIT) have been shown to be effective at speeding V̇O2 kinetics and thus, improving exercise tolerance mainly in middle-aged adults with uncomplicated T2D. However, these effects have not been assessed in older individuals living with T2D.
To further explore these important adaptations, Experiment 1 examined the influence of T2D on muscle deoxygenation ([HHb+Mb]) during ramp incremental cycle exercise in older adults. Fourteen older untrained adults with T2D (62.9 ± 2.8 y; 29.0 ± 3.7 kg.m-2; 9 males/5 females) and 14 untrained older ND controls (64.8 ± 3.9 y; 27.1 ± 2.8 kg.m-2; 10 males/4 females) completed the ramp cycle test. Normalised [HHb+Mb] profiles of the vastus lateralis muscle (%[HHb+Mb]) were plotted as a function of relative peak power output (%PO) using a bilinear model. V̇O2peak was significantly reduced in older individuals with T2D compared to ND controls (27.1 ± 5.7 vs. 23.3 ± 4.0 mL.kg-1.min-1), however, no difference was observed in the primary slope of the Δ%[HHb+Mb]/Δ%PO. These findings suggest that in contrast to middle-aged individuals with T2D, a greater rate of fractional O2 extraction in the exercising musculature for a given increase in V̇O2, indicative of reduced O2 delivery, is not a contributing factor to the reduction in V̇O2peak observed in older individuals with T2D compared to older ND controls.
Experiment 2 investigated the effects of a heavy-intensity PE on a subsequent heavy-intensity cycling exercise in older individuals with T2D (62.5 ± 3 y; 29.4 ± 4.5 kg.m-2; 8 males/1 female) and older ND controls (63.3 ± 3.9 y; 28.4 ± 2.3 kg.m-2; 8 males/1 female). No differences were observed between groups for V̇O2 [HHb+Mb] kinetics in the unprimed bout. Following PE, both groups displayed a significant acceleration for the time constant of the V̇O2 primary phase (τV̇O2P) at the onset of exercise (T2D: 40 ± 3 vs. 32 ± 3 s; ND: 43 ± 5 vs. 34 ± 6 s). A significant reduction in the slow component (V̇O2SC) amplitude was also observed in both groups (T2D: 0.3 ± 0.1 vs. 0.2 ± 0.1 L.min-1; ND: 0.3 ± 0.1 vs. 0.2 ± 0.1 L.min-1). This occurred in conjunction with a slower muscle [HHb+Mb] time constant of the primary phase (Δ[HHb+Mb]τp) in both groups, suggesting an improvement in O2 delivery to utilisation within the exercising muscle which may enhance exercise tolerance in both groups.
When initiating high-intensity exercise from an elevated baseline (work-to-work: WtoW), middle-aged individuals with T2D display a sluggish V̇O2 kinetic response compared to that observed during heavy-intensity exercise initiated from an “unloaded” baseline. The objective of Experiment 3 was to further investigate this influence of PE on V̇O2 and [HHb+Mb] kinetics during a subsequent WtoW exercise bout in older adults with T2D (62.2 ± 2.8 y; 30.1 ± 3.3 kg.m-2; 8 males/2 females) and ND controls (64 ± 4.2 y; 27.6 ± 2.5 kg.m-2; 8 males/2 females). No differences were observed between groups for any responses during the unprimed bouts. Following PE, a reduction occurred in both, the τV̇O2P response (T2D: 49 ± 6 vs. 34 ± 4 s; ND: 49 ± 7 vs. 38 ± 9 s) and the amplitude of the V̇O2SC (T2D: 0.2 ± 0.0 vs. 0.1 ± 0.0 L.min-1; ND: 0.2 ± 0.1 vs. 0.1 ± 0.1 L.min-1). No changes were observed for any [HHb+Mb] responses following PE. These results indicate that PE induced a speeding V̇O2 kinetics response due to a faster contribution from the aerobic metabolism via improvements in O2 delivery as well as an alteration in motor unit recruitment, and that these effects were similar in both groups.
Experiment 4 investigated the effects of 12 weeks of MICT and low-volume HIIT on V̇O2 and [HHb+Mb] kinetics during transitions to heavy-intensity cycling exercise initiated from an unloaded baseline. Participants with T2D were randomly assigned to a control (CON) group (53.9 ± 9.4 y; 30.5 ± 3.6 kg.m-2; 4 males/5 females), a MICT group (54.2 ± 9.9 y; 31.3 ± 5.8 kg.m-2; 7 males/3 females; 50 min of moderate-intensity cycling) and a HIIT group (52 ± 10.1 y; 28.8 ± 3.2 kg.m-2; 6 males/3 females; 10 x 1 min high-intensity bouts at ~90% maximal heart rate interspersed by 1 min of unloaded cycling). Exercise groups trained 3 times per week with the intensity adjusted every 3 weeks. After 12 weeks, τV̇O2P was accelerated for both MICT (35±4 vs. 24±4 s) and HIIT (33±5 vs. 26±3 s) groups, with no differences observed in the CON group (32±4 vs. 31±5 s). Additionally, a significant slowing of the Δ[HHb+Mb]τp response occurred in both exercising groups but not in the control group. Taken together, these results indicate that both exercising groups induced similar benefits in V̇O2 kinetics due to improvements in O2 delivery and/or distribution relative to O2 utilisation.
In conclusion, the accumulated data for the first three experiments of this thesis indicate that no apparent differences in pathophysiological mechanisms are evident with respect to peripheral factors for the impaired exercise tolerance observed in older people with and without T2D. In addition, an acute intervention such as heavy-intensity PE may be effective at improving microvascular blood flow to the exercising muscle, thus, improving the aerobic contribution to exercise and, thereby, increasing exercise tolerance in inactive older adults with and without T2D. Finally, given that the magnitude of effects on V̇O2 kinetics subsequent to low-volume HIIT and MICT were similar in Experiment 4, it is possible that low-volume HIIT, with half the time commitment and volume than MICT, may be a more effective intervention to increase both, exercise involvement and adherence in people with uncomplicated T2D
Viromes of one year old infants reveal the impact of birth mode on microbiome diversity
No full textEstablishing a diverse gut microbiota after birth is being increasingly recognised as
important for preventing illnesses later in life. It is well established that bacterial
diversity rapidly increases post-partum; however, few studies have examined the infant
gut virome/phageome during this developmental period. We performed a metagenomic
analysis of 20 infant faecal viromes at one year of age to determine whether spontaneous
vaginal delivery (SVD) or caesarean section (CS) influenced viral composition. We
find that birth mode results in distinctly different viral communities, with SVD infants
having greater viral and bacteriophage diversity. We demonstrate that CrAssphage is
acquired early in life, both in this cohort and two others, although no difference in
birth mode is detected. A previous study has shown that bacterial OTU’s (operational
taxonomic units) identified in the same infants could not discriminate between birth
mode at 12 months of age. Therefore, our results indicate that vertical transmission
of viral communities from mother to child may play a role in shaping the early life
microbiome, and that birth mode should be considered when studying the early life
gut virome
In vitro screening of different Pseudomonas fluorescens isolates to study lytic enzyme production and growth inhibition during antagonism of Fusarium oxysporum f. sp. cumini, wilt causing pathogen of cumin
No full textLand plants exist in close association with bacterial and fungal microbes, where some associations can be
pathogenic and others can be mutualistic/beneficial. One such relation exists between host plant, Cuminum
cyminum L. (Cumin) and Fusarium oxysporum f. sp. cumini (Foc), the causal pathogen of cumin wilt and
Pseudomonas fluorescens (Pf), where Pf acts as a bio-agent for inhibiting Foc and promoting plant growth of cumin.
In this study, antagonism by 10 different Pf isolates against Foc was studied under laboratory conditions through
percent growth inhibition and biochemical mechanisms. Among these Pf isolates, Pf-5 exhibited the highest in vitro
growth inhibition (82.51%). A positive correlation was observed between percent growth inhibition and specific
activities of hydrolytic enzymes, chitinase, β-1, 3 glucanase, and protease, where a negative correlation was
observed with cell wall degrading enzymes, cellulase and polygalacturonase. To conclude, isolate Pf-5 could be a
potential biocontrol agent for Fusarium wilt disease of cumin
A rapid realist review of quality care process metrics implementation in nursing and midwifery practice
No full textQuality measurement initiatives promote quality improvement in healthcare but can be
challenging to implement effectively. This paper presents a Rapid Realist Review (RRR) of published literature on Quality Care-Process Metrics (QCP-M) implementation in nursing and midwifery practice. An RRR informed by RAMESES II standards was conducted as an efficient means to synthesize evidence using an expert panel. The review involved research question development, quality appraisal, data extraction, and evidence synthesis. Six program theories summarised below identify the key characteristics that promote positive outcomes in QCP-M implementation. Program Theory 1: Focuses on the evidence base and accessibility of the QCP-M and their ease of use by nurses and midwives working in busy and complex care environments. Program Theory 2: Examines
the influence of external factors on QCP-M implementation. Program Theory 3: Relates to existing cultures and systems within clinical sites. Program Theory 4: Relates to nurses’ and midwives’ knowledge and beliefs. Program Theory 5: Builds on the staff theme of Programme Theory four, extending the culture of organizational learning, and highlights the meaningful engagement of nurses and midwives in the implementation process as a key characteristic of success. Program Theory 6: Relates to patient needs. The results provide nursing and midwifery policymakers and professionals with evidence-based program theory that can be translated into action-orientated strategies to help guide successful QCP-M implementation