The acoustic properties of snores

This study was undertaken in an attempt to characterize the acoustic properties of snoring sounds in the time and frequency domains, and to correlate between these properties and the mechanical events underlying their production. Three experimental set-ups were used: 1) Dog model--six mongrel dogs, in which partial upper airway obstruction was created by an implanted supraglottic balloon. Flow, supraglottic pressure, and snoring sounds were recorded during different degrees of obstruction. Fifteen to 20 snores from each dog (total 100 snores) were analysed. 2) Simulated human snores--Six simulated snores from each of four subjects were recorded in two locations (trachea and ambient) with simultaneous airflow, and their correlations examined. 3) Snoring patients--snores were recorded with an ambient microphone from nine subjects with "heavy" snoring and no obstructive sleep apnoea (OSA). Forty to 50 snores from each subject were analysed (total of 400 snores). The snoring sound was analysed in the time (time-expanded waveform) and frequency (power spectrum) domains. After analysing these snores, we were able to identify two dominant patterns which are distinctly different from each other: the "simple-waveform" and the "complex-waveform". The complex-waveform snore is characterized by repetitive, equally-spaced, train of sound structures, starting with a large deflection followed by a decaying amplitude wave. In the frequency domain, it is characterized by multiple, equally-spaced peaks of power (comb-like spectrum). Simple-waveform snores have a quasi-sinusoidal waveform, with a range of variants, and almost no secondary internal oscillations. Their power spectrum contains only 1-3 peaks, of which the first is the most prominent. We developed a mathematical representation of these waveforms, which is presented along with its implications. The complex-waveform snores result from colliding of the airway walls and represent actual brief airway closure. Simple-waveform snores are of higher frequency and probably result from oscillation around a neutral position without actual closure of the lumen.     

Microforms in Gravel Bed Rivers: Formation, Disintegration, and Effects on Bedload Transport

This research aims to advance current knowledge on cluster formation and evolution by tackling some of the aspects associated with cluster microtopography and the effects of clusters on bedload transport. The specific objectives of the study are (1) to identify the bed shear stress range in which clusters form and disintegrate, (2) to quantitatively describe the spacing characteristics and orientation of clusters with respect to flow characteristics, (3) to quantify the effects clusters have on the mean bedload rate, and (4) to assess the effects of clusters on the pulsating nature of bedload. In order to meet the objectives of this study, two main experimental scenarios, namely, Test Series A and B (20 experiments overall) are considered in a laboratory flume under well-controlled conditions. Series A tests are performed to address objectives (1) and (2) while Series B is designed to meet objectives (3) and (4). Results show that cluster microforms develop in uniform sediment at 1.25 to 2 times the Shields parameter of an individual particle and start disintegrating at about 2.25 times the Shields parameter. It is found that during an unsteady flow event, effects of clusters on bedload transport rate can be classified in three different phases: a sink phase where clusters absorb incoming sediment, a neutral phase where clusters do not affect bedload, and a source phase where clusters release particles. Clusters also increase the magnitude of the fluctuations in bedload transport rate, showing that clusters amplify the unsteady nature of bedload transport. A fourth-order autoregressive, autoregressive integrated moving average model is employed to describe the time series of bedload and provide a predictive formula for predicting bedload at different periods. Finally, a change-point analysis enhanced with a binary segmentation procedure is performed to identify the abrupt changes in the bedload statistic characteristics due to the effects of clusters and detect the different phases in bedload time series using probability theory. The analysis verifies the experimental findings that three phases are detected in the bedload rate time series structure, namely, sink, neutral, and source.     

On Jonckheere's k-Sample Test Against Ordered Alternatives

In this paper a k-sample non-parametric test for trend is considered. Given a sample of size n_i , i = 1, …, k respectively from each of k populations, the test rejects the hypothesis that the k populations are identical if S = Σ ^k _i=2 S_i ≥ S_i . Here Si is the Mann-Whitney statistic computed when each observation in the i-th sample is compared with the combined observations from the first (i – 1) populations. A recurrence formula is derived for computing the exact distribution of S. Tables of exact probabilities and critical values are given for nominal values of α = 0.5, 0.2, 0.1, 0.05, 0.025, 0.01, and 0.005 for k = 3 and all possible sample sizes from 2 to 8, and for equal sample sizes for values of n = 2(1)6, k = 4(1)6.     

Building Reusable Remote Labs with Adaptable Client User-Interfaces

Nowadays remote laboratories suffer the absence of reusability. In addition, their construction and maintenance require time, money and skills. The system implementation of a specific remote lab is neither generic nor reusable. In this paper, a solution for a reusable remote lab dedicated for disparate types of scientific and engineering experiments is presented. The experiment designer needs only to connect the experiment components and equipment such as capacitors, resistors, transistors, function generators with a switch system of a lab server, then, she/he has to map this connection structure in a configuration data structure. Once a student starts the Web-based client user-interface and logs-in into the lab server, the menu structure of the graphical user-interface builds and initializes itself automatically, using information stored in a configuration data structure. This contribution discusses some hitherto used lab servers, some of their drawbacks, the desirable requirements on a universal remote lab, which simplify the building process of newer lab experiments consisting of experiment components and equipment as well as a client user-interface that could enable students to remotely access the experiment.     

Least-square identification with error bounds for real-time signalprocessing and control

Set-membership (SM) identification, which refers to a class of algorithms using certain a priori knowledge about a parametric model to constrain the solutions to certain sets, is considered. The focus is on a class of SM-based techniques that are of particular interest in applications requiring real-time processing. The optimal bounding ellipsoid (OBE) algorithms are interpreted as a blending of the classical least-square error minimization approach with knowledge of bounds on model errors arising from SM considerations. Using this interpretation, a general framework embracing all currently used OBE algorithms is developed, and strategies for adaptation and for implementation on parallel machines are discussed. Computational complexity benefits are considered for the various algorithms. The treatment is tutorial, leaving many of the formal details to an appendix that presents an archival theoretical treatment of the key results. A second appendix gives an overview of current research in the general SM identification field     

Economic viability of photovoltaic water pumping systems

A comparison of the economic viability of photovoltaic and diesel water pumping systems is presented for system sizes in the range 2.8 kW_p to 15 kW_p. Actual performance data from installed systems are employed for the base case. Sensitivity analysis is carried out to generalize results for other locations and conditions. The effect of system oversizing due to mismatch of water supply and demand patterns on the economic viability of PV water pumping system is illustrated based on real data and three-year operational experience of eight installations. Investment prospects in PV water pumping applications for different selling price scenarios of water have been investigated.     

Pharmacokinetics of prednisolone transfer to breast milk

A possible interaction of salmon-calcitonin with opioid systems was studied in isolated tissues. Neurogenic contractions were elicited by electrical stimulation in guinea-pig ileum myenteric plexus-longitudinal muscle strips, rabbit vas deferens and mouse vas deferens. Bremazocine inhibited neurogenic contractions in all three tissues (presumably through kappa-receptors) [D-Pen2, D-Pen5]enkephalin and [Met5]enkephalin inhibited contractions in mouse vas deferens (presumably through delta-receptors), and [D-Ala2, N-Me-Phe4, Gly5-ol]enkephalin (DAMGO) inhibited contractions in guinea-pig ileum and mouse vas deferens (presumably through mu-receptors). All inhibitory effects were concentration-dependent. Salmon-calcitonin 0.1 IU/ml increased the effect of bremazocine in guinea-pig ileum and rabbit vas deferens and also increased the effects of [D-Pen2, D-Pen5]enkephalin and [Met5]enkephalin in mouse vas deferens. In contrast, salmon-calcitonin up to 0.4 IU/ml did not change the effect of bremazocine in mouse vas deferens and the effect of DAMGO in guinea-pig ileum and mouse vas deferens. It is concluded that salmon-calcitonin enhances agonist effects at opioid kappa- and delta- but not at opioid mu-receptors. The level of this interaction remains to be elucidated. The interaction may be the basis of the analgesic effect of salmon-calcitonin in vivo.     

Levels of 15 + 1 EU Priority Polycyclic Aromatic Hydrocarbons in Different Edible Oils Available in the Syrian Market

ABSTRACT

The levels of 15 + 1 EU priority polycyclic aromatic hydrocarbons (15 + 1 EU PAHs) have been determined in different edible oils (extra virgin olive oil, virgin olive oil, sunflower oil, corn oil, and soybean oil) available in the Syrian market. The samples have been prepared by donor–acceptor complex chromatography and subsequently characterized by high-pressure liquid chromatography coupled with fluorescence and ultraviolet detection for quantification purposes. Variable levels of contamination have been found within different kinds of edible oil samples, and only chrysene has been detected in all the studied samples. Moreover, the mean total sum of 15 + 1 EU PAHs has shown variation from 29.8 µg/kg (corn oil) to 63.7 µg/kg (virgin olive oil). A total of 11 samples out of 38 samples (28.9%) have not fulfilled the European Union (EU) food law requirements. Nine samples have exceeded the EU legislation limit of benzo[a]pyrene (BaP) (2 µg/kg) and only two samples have exceeded the EU legislation limit of PAH4 (10 µg/kg) and had acceptable level of BaP. Finally, the mean and maximum dietary exposures of PAHs through consumption of edible oils have been estimated.     

The Distribution of the Maximum Sum of Rank

In this paper a c-sample slippage analogue of the Wilcoxon [11] test is considered. Given a sample of size n for each of c populations, the test rejects the hypothesis that the c populations are identical when max_1≤i≤c σ _k r _ik > λ, where r _i1, …, r _in are the ranks of the observations from the i-th population in the combined sample of size cn. The small and large sample distributions of the test statistic are derived. Tables of the exact distribution are given for c = 2(1)5, n = 2(1)5. Tables of critical values are given for c = 2(1)6, n = 2(1)8 for values of α = 0.001, 0.005, 0.01, 0.025, 0.05, 0.10, and 0.20.