Estimation of room acoustic parameters: the ACE challenge

Reverberation Time (T60) and Direct-to-Reverberant Ratio (DRR) are important parameters which together can characterize sound captured by microphones in non-anechoic rooms. These parameters are important in speech processing applications such as speech recognition and dereverberation. The values of T60 and DRR can be estimated directly from the Acoustic Impulse Response (AIR) of the room. In practice, the AIR is not normally available, in which case these parameters must be estimated blindly from the observed speech in the microphone signal. The Acoustic Characterization of Environments (ACE) Challenge aimed to determine the state-of-the-art in blind acoustic parameter estimation and also to stimulate research in this area. A summary of the ACE Challenge, and the corpus used in the challenge is presented together with an analysis of the results. Existing algorithms were submitted alongside novel contributions, the comparative results for which are presented in this paper. The challenge showed that T60 estimation is a mature field where analytical approaches dominate whilst DRR estimation is a less mature field where machine learning approaches are currently more successful

No evidence for intense, cold accretion on to YSOs from measurements of Li in T-Tauri stars

We have used medium-resolution spectra to search for evidence that proto-stellar objects accrete at high rates during their early 'assembly phase'. Models predict that depleted lithium and reduced luminosity in T-Tauri stars are key signatures of 'cold' high-rate accretion occurring early in a star's evolution. We found no evidence in 168 stars in NGC 2264 and the Orion nebula cluster for strong lithium depletion through analysis of veiling-corrected 6708Å lithium spectral line strengths. This suggests that 'cold' accretion at high rates (M = 5 × 10-4 M⊙ yr-1) occurs in the assembly phase of fewer than 0.5 per cent of 0.3 = M⊙ = 1.9M⊙ stars. We also find that the dispersion in the strength of the 6708Å lithium line might imply an age spread that is similar in magnitude to the apparent age spread implied by the luminosity dispersion seen in colour-magnitude diagrams. Evidence for weak lithium depletion (<10 per cent in equivalent width) that is correlated with luminosity is also apparent, but we are unable to determine whether age spreads or accretion at rates less than 5 × 10-4 M⊙ yr-1 are responsible. ©2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.DJS is funded by a UK Science and Technology Facilities Council (STFC) studentship. The authors wish to thank Isabelle Baraffe for providing cold accretion models and useful discussions. Spectra were extracted and calibrated using the AF2 pipeline developed by Richard Jackson. This research is based on observations made with the William Herschel Telescope operated on the island of La Palma by the Isaac Newton Group (ING) in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. This research has made use of archival data products from the Two-Micron All-Sky Survey (2MASS), which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, funded by the National Aeronautics and Space Administration (NASA) and the National Science Foundation

Muscle size explains low passive skeletal muscle force in heart failure patients.

BACKGROUND: Alterations in skeletal muscle function and architecture have been linked to the compromised exercise capacity characterizing chronic heart failure (CHF). However, how passive skeletal muscle force is affected in CHF is not clear. Understanding passive force characteristics in CHF can help further elucidate the extent to which altered contractile properties and/or architecture might affect muscle and locomotor function. Therefore, the aim of this study was to investigate passive force in a single muscle for which non-invasive measures of muscle size and estimates of fiber force are possible, the soleus (SOL), both in CHF patients and age- and physical activity-matched control participants. METHODS: Passive SOL muscle force and size were obtained by means of a novel approach combining experimental data (dynamometry, electromyography, ultrasound imaging) with a musculoskeletal model. RESULTS: We found reduced passive SOL forces (∼30%) (at the same relative levels of muscle stretch) in CHF vs. healthy individuals. This difference was eliminated when force was normalized by physiological cross sectional area, indicating that reduced force output may be most strongly associated with muscle size. Nevertheless, passive force was significantly higher in CHF at a given absolute muscle length (non length-normalized) and likely explained by the shorter muscle slack lengths and optimal muscle lengths measured in CHF compared to the control participants. This later factor may lead to altered performance of the SOL in functional tasks such gait. DISCUSSION: These findings suggest introducing exercise rehabilitation targeting muscle hypertrophy and, specifically for the calf muscles, exercise that promotes muscle lengthening

Impact of handgrip exercise intensity on brachial artery flow-mediated dilation.

PURPOSE: Previous studies that have examined the impact of exercise intensity on conduit artery endothelial function have involved large muscle group exercise which induces local and systemic effects. The aim of this study was to examine flow-mediated dilation (FMD) before and after incremental intensities of handgrip exercise (HE), to assess the role of local factors such as blood flow and shear rate on post-exercise brachial artery function. METHODS: Eleven healthy men attended the laboratory on three occasions. Subjects undertook 30 min of handgrip exercise at three intensities (5, 10 or 15 % MVC). Brachial artery FMD, shear and blood flow patterns were examined before, immediately after and 60 min post exercise. RESULTS: Handgrip exercise increased mean and antegrade shear rate (SR) and blood flow (BF) and reduced retrograde SR and BF (all P < 0.01). Exercise intensity was associated with a dose-dependent increase in both mean and antegrade BF and SR (interaction, P < 0.01). Post-hoc tests revealed that, whilst handgrip exercise did not immediately induce post-exercise changes, FMD was significantly higher 60 min post-exercise following the highest exercise intensity (5.9 ± 2.8-10.4 ± 5.8 %, P = 0.01). CONCLUSIONS: Handgrip exercise leads to intensity-and time-dependent changes in conduit artery function, possibly mediated by local increases in shear, with improvement in function evident at 1 h post-exercise when performed at a higher intensity

Brachial and Cerebrovascular Functions Are Enhanced in Postmenopausal Women after Ingestion of Chocolate with a High Concentration of Cocoa.

Background: Cocoa contains polyphenols that are thought to be beneficial for vascular health.Objective: We assessed the impact of chocolate containing distinct concentrations of cocoa on cerebrovascular function and cognition.Methods: Using a counterbalanced within-subject design, we compared the acute impact of consumption of energy-matched chocolate containing 80%, 35%, and 0% single-origin cacao on vascular endothelial function, cognition, and cerebrovascular function in 12 healthy postmenopausal women (mean ± SD age: 57.3 ± 5.3 y). Participants attended a familiarization session, followed by 3 experimental trials, each separated by 1 wk. Outcome measures included cerebral blood flow velocity (CBFv) responses, recorded before and during completion of a computerized cognitive assessment battery (CogState); brachial artery flow-mediated dilation (FMD); and hemodynamic responses (heart rate and blood pressure).Results: When CBFv data before and after chocolate intake were compared between conditions through the use of 2-factor ANOVA, an interaction effect (P = 0.003) and main effects for chocolate (P = 0.043) and time (P = 0.001) were evident. Post hoc analysis revealed that both milk chocolate (MC; 35% cocoa; P = 0.02) and dark chocolate (DC; 80% cocoa; P = 0.003) induced significantly lower cerebral blood flow responses during the cognitive tasks, after normalizing for changes in arterial pressure. DC consumption also increased brachial FMD compared with the baseline value before chocolate consumption (P = 0.002), whereas MC and white chocolate (0% cocoa) caused no change (P-interaction between conditions = 0.034).Conclusions: Consumption of chocolate containing high concentrations of cocoa enhanced vascular endothelial function, which was reflected by improvements in FMD. Cognitive function outcomes did not differ between conditions; however, cerebral blood flow responses during these cognitive tasks were lower in those consuming MC and DC. These findings suggest that chocolate containing high concentrations of cocoa may modify the relation between cerebral metabolism and blood flow responses in postmenopausal women. This trial was registered at www.ANZCTR.orgau as ACTRN12616000990426

Impact of commonly prescribed exercise interventions on platelet activation in physically inactive and overweight men.

The exercise paradox infers that, despite the well-established cardioprotective effects of repeated episodic exercise (training), the risk of acute atherothrombotic events may be transiently increased during and soon after an exercise bout. However, the acute impact of different exercise modalities on platelet function has not previously been addressed. We hypothesized that distinct modalities of exercise would have differing effects on in vivo platelet activation and reactivity to agonists which induce monocyte-platelet aggregate (MPA) formation. Eight middle-aged (53.5 ± 1.6 years) male participants took part in four 30 min experimental interventions (aerobic AE, resistance RE, combined aerobic/resistance exercise CARE, or no-exercise NE), in random order. Blood samples were collected before, immediately after, and 1 h after each intervention, and incubated with one of three agonists of physiologically/clinically relevant pathways of platelet activation (thrombin receptor activating peptide-6 TRAP, arachidonic acid AA, and cross-linked collagen-related peptide xCRP). In the presence of AA, TRAP, and xCRP, both RE and CARE evoked increases in MPAs immediately post-exercise (P < 0.01), whereas only AA significantly increased MPAs immediately after AE (P < 0.01). These increases in platelet activation post-exercise were transient, as responses approached pre-exercise levels by 1 h. These are the first data to suggest that exercise involving a resistance component in humans may transiently increase platelet-mediated thrombotic risk more than aerobic modalities

Heat shock protein 10 inhibits lipopolysaccharide-induced inflammatory mediator production

Heat shock protein 10 (Hsp10) and heat shock protein 160 (Hsp60) were originally described as essential mitochondrial proteins involved in protein folding. How,ever, both proteins have also been shown to have a number of extracellular immunomodulatory activities. Here we show that purified recombinant human Hsp10 incubated with cells in vitro reduced lipopolysaccharide (LPS)-induced nuclear factor-kappaB activation and secretion of several inflammatory mediators from RAW264.7 cells, murine macrophages, and human peripheral blood mononuclear cells. Induction of tolerance by contaminating LPS was formally excluded as being responsible for Hsp10 activity. Treatment of mice with Hsp10 before,endotoxin challenge resulted in the reduction of serum tumor necrosis factor-a and RANTES (regulated upon activation, normal T cell expressed and secreted) levels and an elevation of serum interleukin-10 levels. Hsp10 treatment also delayed mortality in a murine graft-ver-sus-host disease model, where gut-derived LPS contributes to pathology. We were unable to confirm previous reports that Hsp10 has tumor growth factor properties and suggest that Hsp10 exerts anti-inflammatory activity by inhibiting Toll-like receptor signaling possibly by interacting with extracellular Hsp60

Consumption of dark chocolate attenuates subsequent food intake compared with milk and white chocolate in postmenopausal women.

BACKGROUND: Chocolate has a reputation for contributing to weight gain due to its high fat, sugar and calorie content. However, the effect of varying concentrations of cocoa in chocolate on energy intake and appetite is not clear. OBJECTIVE: To compare the acute effect of consuming an isocaloric dose of dark, milk and white chocolate on subsequent energy intake, appetite and mood in postmenopausal women. METHODS: Fourteen healthy postmenopausal women (57.6 ± 4.8yr) attended an introductory session followed by three experimental trials performed in a counterbalanced order at a standardised time of day, each separated by one week. Ad libitum energy intake, perceived appetite, mood and appetite-related peptides were assessed in response to consumption of 80% cocoa [dark chocolate], 35% cocoa [milk chocolate] and cocoa butter [white chocolate] (2099 kJ), prepared from a single-origin cacao bean. RESULTS: Ad libitum energy intake was significantly lower following dark (1355 ± 750 kJ) compared with both milk (1693 ± 969 kJ; P = 0.008) and white (1842 ± 756 kJ; P = 0.001) chocolate consumption. Blood glucose and insulin concentrations were transiently elevated in response to white and milk chocolate consumption compared with the dark chocolate (P  0.05). CONCLUSIONS: Dark chocolate attenuates subsequent food intake in postmenopausal women, compared to the impact of milk and white chocolate consumption

Differential impact of water immersion on arterial blood flow and shear stress in the carotid and brachial arteries of humans.

Arterial shear stress is a potent stimulus to vascular adaptation in humans. Typically, increases in retrograde shear have been found to acutely impair vascular function while increases in antegrade shear enhance function. We hypothesized that blood flow and shear stress through the brachial and carotid arteries would change in a similar manner in response to water immersion, an intervention which modifies hemodynamics. Nine healthy young male subjects were recruited to undergo controlled water immersion in a standing upright position to the level of the right atrium in 30°C water. Diameters were continuously and simultaneously recorded in the brachial and common carotid arteries along with mean arterial pressure (MAP), cardiac output (CO), and heart rate before, during, and after 10 min of immersion. MAP and CO increased during water immersion (baseline vs. 8-10 min; 80 ± 9 vs. 91 ± 12 mmHg; and 4.8 ± 0.7 vs. 5.1 ± 0.6 L/min, P < 0.01 and P < 0.05, respectively). We observed a differential regulation of flow and shear stress patterns in the brachial and carotid arteries in response to water immersion; brachial conductance decreased markedly in response to immersion (1.25 ± 0.56 vs. 0.57 ± 0.30 mL.min/mmHg, P < 0.05), whereas it was unaltered in the carotid artery (5.82 ± 2.14 vs. 5.60 ± 1.59). Our findings indicate that adaptations to systemic stimuli and arterial adaptation may be vessel bed specific in humans, highlighting the need to assess multiple vascular sites in future studies

Decision-making in percutaneous coronary intervention: a survey

<p>Abstract</p> <p>Background</p> <p>Few researchers have examined the perceptions of physicians referring cases for angiography regarding the degree to which collaboration occurs during percutaneous coronary intervention (PCI) decision-making. We sought to determine perceptions of physicians concerning their involvement in PCI decisions in cases they had referred to the cardiac catheterization laboratory at a major academic medical center.</p> <p>Methods</p> <p>An anonymous survey was mailed to internal medicine faculty members at a major academic medical center. The survey elicited whether responders perceived that they were included in decision-making regarding PCI, and whether they considered such collaboration to be the best process of decision-making.</p> <p>Results</p> <p>Of the 378 surveys mailed, 35% (133) were returned. Among responding non-cardiologists, 89% indicated that in most cases, PCI decisions were made solely by the interventionalist at the time of the angiogram. Among cardiologists, 92% indicated that they discussed the findings with the interventionalist prior to any PCI decisions. When asked what they considered the best process by which PCI decisions are made, 66% of non-cardiologists answered that they would prefer collaboration between either themselves or a non-interventional cardiologist and the interventionalist. Among cardiologists, 95% agreed that a collaborative approach is best.</p> <p>Conclusion</p> <p>Both non-cardiologists and cardiologists felt that involving another decision-maker, either the referring physician or a non-interventional cardiologist, would be the best way to make PCI decisions. Among cardiologists, there was more concordance between what they believed was the best process for making decisions regarding PCI and what they perceived to be the actual process.</p