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Sample records for 2-min tidal breathing

  1. Patient-specific simulation of tidal breathing

    NASA Astrophysics Data System (ADS)

    Walters, M.; Wells, A. K.; Jones, I. P.; Hamill, I. S.; Veeckmans, B.; Vos, W.; Lefevre, C.; Fetitia, C.

    2016-03-01

    Patient-specific simulation of air flows in lungs is now straightforward using segmented airways trees from CT scans as the basis for Computational Fluid Dynamics (CFD) simulations. These models generally use static geometries, which do not account for the motion of the lungs and its influence on important clinical indicators, such as airway resistance. This paper is concerned with the simulation of tidal breathing, including the dynamic motion of the lungs, and the required analysis workflow. Geometries are based on CT scans obtained at the extremes of the breathing cycle, Total Lung Capacity (TLC) and Functional Residual Capacity (FRC). It describes how topologically consistent geometries are obtained at TLC and FRC, using a `skeleton' of the network of airway branches. From this a 3D computational mesh which morphs between TLC and FRC is generated. CFD results for a number of patient-specific cases, healthy and asthmatic, are presented. Finally their potential use in evaluation of the progress of the disease is discussed, focusing on an important clinical indicator, the airway resistance.

  2. Methacholine bronchial challenge using a dosimeter with controlled tidal breathing.

    PubMed Central

    Nieminen, M M; Lahdensuo, A; Kellomaeki, L; Karvonen, J; Muittari, A

    1988-01-01

    A new inhalation synchronised dosimeter triggered by low inspiratory flow rates has been assessed. The methacholine challenge test using dosimeter nebulisation with controlled tidal breathing was compared with continuous nebulisation using De Vilbiss No 40 nebulisers with deep inhalations in 11 asthmatic subjects. Within subject PD20 FEV1 values were lower with the dosimeter method than with the continuous nebulisation method (geometric means 158 and 588 micrograms). The repeatability of the dosimeter method with controlled tidal breathing was studied in 11 asthmatic subjects, and the 95% range for a single measurement was +/- 0.72 doubling doses of methacholine. The dosimeter method has greater efficacy because aerosol is delivered during the first part of an inhalation, minimising loss of aerosol outside the respiratory tract. The dosimeter technique combined with controlled tidal breathing appears to be a useful method for carrying out standardised non-specific bronchoprovocation tests. Images PMID:3065974

  3. Physiological techniques for detecting expiratory flow limitation during tidal breathing.

    PubMed

    Koulouris, N G; Hardavella, G

    2011-09-01

    Patients with severe chronic obstructive pulmonary disease (COPD) often exhale along the same flow-volume curve during quiet breathing as they do during the forced expiratory vital capacity manoeuvre, and this has been taken as an indicator of expiratory flow limitation at rest (EFL(T)). Therefore, EFL(T), namely attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow. EFL(T) leads to small airway injury and promotes dynamic pulmonary hyperinflation, with concurrent dyspnoea and exercise limitation. In fact, EFL(T) occurs commonly in COPD patients (mainly in Global Initiative for Chronic Obstructive Lung Disease III and IV stage), in whom the latter symptoms are common, but is not exclusive to COPD, since it can also be detected in other pulmonary and nonpulmonary diseases like asthma, acute respiratory distress syndrome, heart failure and obesity, etc. The existing up to date physiological techniques of assessing EFL(T) are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, noninvasive, practical and accurate new technique.

  4. Physiological techniques for detecting expiratory flow limitation during tidal breathing.

    PubMed

    Koulouris, N G; Hardavella, G

    2011-09-01

    Patients with severe chronic obstructive pulmonary disease (COPD) often exhale along the same flow-volume curve during quiet breathing as they do during the forced expiratory vital capacity manoeuvre, and this has been taken as an indicator of expiratory flow limitation at rest (EFL(T)). Therefore, EFL(T), namely attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow. EFL(T) leads to small airway injury and promotes dynamic pulmonary hyperinflation, with concurrent dyspnoea and exercise limitation. In fact, EFL(T) occurs commonly in COPD patients (mainly in Global Initiative for Chronic Obstructive Lung Disease III and IV stage), in whom the latter symptoms are common, but is not exclusive to COPD, since it can also be detected in other pulmonary and nonpulmonary diseases like asthma, acute respiratory distress syndrome, heart failure and obesity, etc. The existing up to date physiological techniques of assessing EFL(T) are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, noninvasive, practical and accurate new technique. PMID:21881143

  5. Measuring tidal breathing parameters using a volumetric vest in neonates with and without lung disease.

    PubMed

    Olden, C; Symes, E; Seddon, P

    2010-11-01

    Lung function measurement is difficult in unsedated infants; tidal breathing parameters are a useful non-invasive surrogate, but even these measurements cause disturbance from applying a facemask. We investigated a novel volumetric vest system (FloRight), which measures volume changes of the respiratory system from changes in the magnetic fields induced by current-carrying coils around the entire chest and abdomen. Using a facemask and ultrasonic flowmeter as comparator, we assessed the validity and repeatability of tidal breathing parameters measured by FloRight in 10 healthy newborn infants during natural sleep. We also assessed the effect of a facemask on tidal volume and tidal expiratory flow parameters. To assess the ability of the FloRight system to detect disease, we compared the healthy infants with 11 infants suffering from bronchopulmonary dysplasia. Tidal parameters with the FloRight vest corresponded closely with facemask measurements. Mean difference, mask minus vest, for tidal volume was 0.096 ml (P < 0.05), with limits of agreement +4.5 to -4.3 ml. Coefficient of repeatability was similar for mask and vest measurements. Tidal volume measured by FloRight with mask in place (20.6 ml) was significantly higher than without mask (16.1 ml), but tidal expiratory flow parameters were not altered. FloRight measurements of tidal parameters were markedly different between the two groups of infants, with tidal volume per Kg significantly higher and tidal expiratory flow parameters significantly lower. Our findings suggest that the FloRight system is able to measure tidal breathing parameters accurately, in healthy newborn infants, without prior calibration on the infant. It appears to have at least sufficient sensitivity to detect severe respiratory disease. PMID:20872815

  6. Correlational analysis of electroencephalographic and end-tidal carbon dioxide signals during breath-hold exercise.

    PubMed

    Morelli, Maria Sole; Vanello, Nicola; Giannoni, Alberto; Frijia, Francesca; Hartwig, Valentina; Maestri, Michelangelo; Bonanni, Enrica; Carnicelli, Luca; Positano, Vincenzo; Passino, Claudio; Emdin, Michele; Landini, Luigi

    2015-01-01

    The central mechanism of breathing control is not totally understood. Several studies evaluated the correlation between electroencephalographic (EEG) power spectra and respiratory signals by performing resting state tasks or adopting hypercapnic/hypoxic stimuli. The observation of brain activity during voluntary breath hold tasks, might be an useful approach to highlight the areas involved in mechanism of breath regulation. Nevertheless, studies of brain activity with EEG could present some limitations due to presence of severe artifacts. When artifact rejection methods, as independent component analysis, cannot reliably clean EEG data, it is necessary to exclude noisy segments. In this study, global field power in the delta band and end-tidal CO2 were derived from EEG and CO2 signals respectively in 4 healthy subjects during a breath-hold task. The cross correlation function between the two signals was estimated taking into account the presence of missing samples. The statistical significance of the correlation coefficients at different time lags was assessed using surrogate data. Some simulations are introduced to evaluate the effect of missing data on the correlational analysis and their results are discussed. Results obtained on subjects show a significant correlation between changes in EEG power in the delta band and end-tidal CO2. Moreover, the changes in end-tidal CO2 were found to precede those of global field power. These results might help to better understand the cortical mechanisms involved in the control of breathing. PMID:26737684

  7. Correlational analysis of electroencephalographic and end-tidal carbon dioxide signals during breath-hold exercise.

    PubMed

    Morelli, Maria Sole; Vanello, Nicola; Giannoni, Alberto; Frijia, Francesca; Hartwig, Valentina; Maestri, Michelangelo; Bonanni, Enrica; Carnicelli, Luca; Positano, Vincenzo; Passino, Claudio; Emdin, Michele; Landini, Luigi

    2015-01-01

    The central mechanism of breathing control is not totally understood. Several studies evaluated the correlation between electroencephalographic (EEG) power spectra and respiratory signals by performing resting state tasks or adopting hypercapnic/hypoxic stimuli. The observation of brain activity during voluntary breath hold tasks, might be an useful approach to highlight the areas involved in mechanism of breath regulation. Nevertheless, studies of brain activity with EEG could present some limitations due to presence of severe artifacts. When artifact rejection methods, as independent component analysis, cannot reliably clean EEG data, it is necessary to exclude noisy segments. In this study, global field power in the delta band and end-tidal CO2 were derived from EEG and CO2 signals respectively in 4 healthy subjects during a breath-hold task. The cross correlation function between the two signals was estimated taking into account the presence of missing samples. The statistical significance of the correlation coefficients at different time lags was assessed using surrogate data. Some simulations are introduced to evaluate the effect of missing data on the correlational analysis and their results are discussed. Results obtained on subjects show a significant correlation between changes in EEG power in the delta band and end-tidal CO2. Moreover, the changes in end-tidal CO2 were found to precede those of global field power. These results might help to better understand the cortical mechanisms involved in the control of breathing.

  8. Electromagnetic inductance plethysmography to measure tidal breathing in preterm and term infants.

    PubMed

    Pickerd, N; Williams, E M; Kotecha, S

    2013-02-01

    Tidal breathing measurements which provide a non-invasive measure of lung function in preterm and term infants are particularly useful to guide respiratory support. We used a new technique of electromagnetic inductance plethysmography (EIP) to measure tidal breathing in infants between 32 and 42 weeks postconceptional age (PCA). Tidal breathing was measured in 49 healthy spontaneously breathing infants between 32 and 42 weeks PCA. The weight-corrected tidal volume (V(T) ) and minute volume (MV) decreased with advancing PCA (V(T) 6.5 ± 1.5 ml/kg and MV 0.44 ± 0.04 L/kg/min at 32-33 weeks, respectively; 6.3 ± 0.9 ml/kg and 0.38 ± 0.02 L/kg/min at 34-36 weeks; and 5.1 ± 1.1 ml/kg and 0.28 ± 0.02 L/kg/min at term, V(T) P < 0.001 and MV P < 0.01 for 32-33 weeks PCA vs. term; V(T) P = 0.016 and MV P = 0.015 for 34-36 weeks PCA vs. term). Respiratory frequency and the phase angle decreased significantly with advancing PCA but the flow parameter t(PTEF) /t(E) did not change significantly. Using a new technique to measure tidal breathing parameters in newborn infants, our data confirms its usability in clinical practice and establishes normative data which can guide future respiratory management of newborn infants.

  9. Nitrogen washout during tidal breathing with superimposed high-frequency chest wall oscillation.

    PubMed

    Harf, A; Zidulka, A; Chang, H K

    1985-08-01

    In order to assess the efficacy of high-frequency chest wall oscillation (HFCWO) superimposed on tidal ventilation, multiple-breath nitrogen washout curves were obtained in 7 normal seated subjects. To maintain a regular breathing pattern throughout the study, the subjects breathed synchronously with a Harvard ventilator set at a constant tidal volume and frequency for each subject during a trial period. Washout curves were obtained during 3 different maneuvers performed in random order. Series A was the control condition with no superimposed HFCWO. In Series B and C, HFCWO at 5 Hz was superimposed on the regulated tidal breathing; the magnitude of the oscillatory tidal volume measured at the airway opening was 20 ml for Series B and 40 ml for Series C. The nitrogen washout was clearly faster in Series C than in Series A for each subject. In Series B, there was an interindividual variability, with a washout rate either equal to that in Maneuver A or in Maneuver C, or intermediate between the two. When these washout curves were analyzed in terms of a simple monocompartment model, the time constant of the washout was found to decrease by 16 +/- 11% in Series B, and 25 +/- 7% in Series C compared with that in Series A. In this group of normal subjects, the correction of any inhomogeneity in the distribution of the ventilation is unlikely to explain these results because of the close fit of all washout curves to a monoexponential model. It is postulated that during inspiration HFCWO enhances gas mixing in the lung periphery and that during expiration it improves gas mixing in the airways.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Interpretation of the krypton-81m dynamic series: the distribution of a tidal breath

    SciTech Connect

    Shykoff, B.E.; Cinotti, L.; Meignan, M.; Harf, A.; Chang, H.K.

    1988-12-01

    Lung scans during cyclic breathing of krypton-81m, an isotope with a 13-s half-life, were acquired in list mode, where both temporal and spatial information are preserved. Subjects in the left lateral decubitus position breathed with two tidal volumes at each of two frequencies. Profiles of total activity over the acquisition period were examined. They showed little effect of frequency or tidal volume on the distribution of air between dependent and non-dependent regions. Dynamic series for ensemble-averaged breaths were constructed. The regional flow per unit volume was shown to correspond to the time derivative of the regional activity of the dynamic series divided by the corresponding activity. Both the relative timing of the gas flow to different lung regions and the flow per unit volume as a function of time were obtained from the dynamic series. The dependent lung was seen to be better ventilated throughout the respiratory cycle except for brief periods at the start of inspiration and the end of expiration. Most of the dead-space gas can be construed to enter and leave the dependent lung.

  11. 4DCT-based assessment of regional airflow distribution in healthy human lungs during tidal breathing

    NASA Astrophysics Data System (ADS)

    Choi, Jiwoong; Jahani, Nariman; Choi, Sanghun; Hoffman, Eric; Lin, Ching-Long

    2014-11-01

    Nonlinear dynamics of regional airflow distribution in healthy human lungs are studied with four-dimensional computed tomography (4DCT) quantitative imaging of four subjects. During the scanning session, subjects continuously breathed with tidal volumes controlled by the dual piston system. For each subject, 10 instantaneous volumetric image data sets (5 inspiratory and 5 expiratory phases) were reconstructed. A mass-preserving image registration was then applied to pairs of these image data to construct a breathing lung model. Regional distributions of local flow rate fractions are computed from time-varying local air volumes. The 4DCT registration-based method provides the link between local and global air volumes of the lung, allowing derivation of time-varying regional flow rates during the tidal breathing for computational fluid dynamics analysis. The local flow rate fraction remains greater in the lower lobes than in the upper lobes, being qualitatively consistent with those derived from three static CT (3SCT) images (Yin et al. JCP 2013). However, unlike 3SCT, the 4DCT data exhibit lung hysteresis between inspiration and expiration, providing more sensitive measures of regional ventilation and lung mechanics. NIH Grants U01-HL114494, R01-HL094315 and S10-RR022421.

  12. Investigating in vivo airway wall mechanics during tidal breathing with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Robertson, Claire; Lee, Sang-Won; Ahn, Yeh-Chan; Mahon, Sari; Chen, Zhongping; Brenner, Matthew; George, Steven C.

    2011-10-01

    Optical coherence tomography (OCT) is a nondestructive imaging technique offering high temporal and spatial resolution, which makes it a natural choice for assessing tissue mechanical properties. We have developed methods to mechanically analyze the compliance of the rabbit trachea in vivo using tissue deformations induced by tidal breathing, offering a unique tool to assess the behavior of the airways during their normal function. Four-hundred images were acquired during tidal breathing with a custom-built endoscopic OCT system. The surface of the tissue was extracted from a set of these images via image processing algorithms, filtered with a bandpass filter set at respiration frequency to remove cardiac and probe motion, and compared to ventilatory pressure to calculate wall compliance. These algorithms were tested on elastic phantoms to establish reliability and reproducibility. The mean tracheal wall compliance (in five animals) was 1.3+/-0.3×10-5 (mm Pa)-1. Unlike previous work evaluating airway mechanics, this new method is applicable in vivo, noncontact, and loads the trachea in a physiological manner. The technique may have applications in assessing airway mechanics in diseases such as asthma that are characterized by significant airway remodeling.

  13. Investigating in vivo airway wall mechanics during tidal breathing with optical coherence tomography

    PubMed Central

    Robertson, Claire; Lee, Sang-Won; Ahn, Yeh-Chan; Mahon, Sari; Chen, Zhongping; Brenner, Matthew; George, Steven C.

    2011-01-01

    Optical coherence tomography (OCT) is a nondestructive imaging technique offering high temporal and spatial resolution, which makes it a natural choice for assessing tissue mechanical properties. We have developed methods to mechanically analyze the compliance of the rabbit trachea in vivo using tissue deformations induced by tidal breathing, offering a unique tool to assess the behavior of the airways during their normal function. Four-hundred images were acquired during tidal breathing with a custom-built endoscopic OCT system. The surface of the tissue was extracted from a set of these images via image processing algorithms, filtered with a bandpass filter set at respiration frequency to remove cardiac and probe motion, and compared to ventilatory pressure to calculate wall compliance. These algorithms were tested on elastic phantoms to establish reliability and reproducibility. The mean tracheal wall compliance (in five animals) was 1.3±0.3×10−5 (mm Pa)−1. Unlike previous work evaluating airway mechanics, this new method is applicable in vivo, noncontact, and loads the trachea in a physiological manner. The technique may have applications in assessing airway mechanics in diseases such as asthma that are characterized by significant airway remodeling. PMID:22029358

  14. Evaluation of an end-tidal portable ETCO2 colorimetric breath indicator (COLIBRI).

    PubMed

    Rabitsch, Werner; Nikolic, Ajsa; Schellongowski, Peter; Kofler, Julia; Kraft, Peter; Krenn, Claus G; Staudinger, Thomas; Locker, Gottfried J; Knöbl, Paul; Hofbauer, Roland; Frass, Michael

    2004-01-01

    Evaluation of tube position is important after in-hospital and prehospital emergency intubation. Colorimetric breath indicators are devices for immediate control of tube positioning by showing a color change according to end-tidal CO2 (ETCO2) concentrations. We hypothesized that colorimetric breath indicators can yield reliable results for confirmation of tube position. The aim of this study was to evaluate the effectiveness and safety of a new colorimetric breath indicator (Colibri, ICOR AB, Bromma, Sweden) in 147 patients during general anesthesia, in critically ill patients, during transport to in-hospital interventions, and in a study design after insertion of a second tube into the esophagus in long-term ventilated patients. The Colibri was attached between the respective airway and ventilatory tubing. Seventy-three patients were investigated during general anesthesia, 39 patients were observed during long-term ventilation with an average duration of 33 hours, in 15 patients during transport to an intervention for up to 4 hours, and in 20 long-term ventilated patients at the medical intensive-care unit after insertion of a second tube intentionally into the esophagus with the help of a laryngoscope. The Colibri worked well in all groups investigated and showed no false results in the group with tubes inserted into the trachea and esophagus. Data suggest that the Colibri might serve as a valuable tool for evaluating and controlling tube position. This device is independent of power supply or electronic equipment, portable, small, and immediately ready for use.

  15. Spectral characteristics of airway opening and chest wall tidal flows in spontaneously breathing preterm infants.

    PubMed

    Habib, Robert H; Pyon, Kee H; Courtney, Sherry E; Aghai, Zubair H

    2003-05-01

    We compared the harmonic content of tidal flows measured simultaneously at the mouth and chest wall in spontaneously breathing very low birth weight infants (n = 16, 1,114 +/- 230 g, gestation age: 28 +/- 2 wk). Airway opening flows were measured via face mask-pneumotachograph (P-tach), whereas chest wall flows were derived from respiratory inductance plethysmography (RIP) excursions. Next, for each, we computed two spectral shape indexes: 1) harmonic distortion (k(d); k(d,P-tach) and k(d,RIP), respectively) defines the extent to which flows deviated from a single sine wave, and 2) the exponent of the power law (s; s(P-tach) and s(RIP), respectively), describing the spectral energy vs. frequency. P-tach and RIP flow spectra exhibited similar power law functional forms consistently in all infants. Also, mouth [s(P-tach) = 3.73 +/- 0.23% (95% confidence interval), k(d,P-tach) = 38.8 +/- 4.6%] and chest wall (s(RIP) = 3.51 +/- 0.30%, k(d,RIP) = 42.8 +/- 4.8%) indexes were similar and highly correlated (s(RIP) = 1.17 x s(P-tach) + 0.85; r(2) = 0.81; k(d,RIP) = 0.90 x k(d,P-tach) + 8.0; r(2) = 0.76). The corresponding time to peak tidal expiratory flow-to-expiratory time ratio (0.62 +/- 0.08) was higher than reported in older infants. The obtained s and k(d) values are similar to those reported in older and/or larger chronic lung disease infants, yet appreciably lower than for 1-mo-old healthy infants of closer age and/or size; this indicated increased complexity of tidal flows in very low birth weight babies. Importantly, we found equivalent flow spectral data from mouth and chest wall tidal flows. The latter are desirable because they avoid face mask artificial effects, including leaks around it, they do not interfere with ventilatory support delivery, and they may facilitate longer measurements that are useful in control of breathing assessment.

  16. Tidal volume single-breath washin of SF6 and CH4 in transient microgravity

    NASA Technical Reports Server (NTRS)

    Dutrieue, Brigitte; Paiva, Manuel; Verbanck, Sylvia; Le Gouic, Marine; Darquenne, Chantal; Prisk, G. Kim

    2003-01-01

    We performed tidal volume single-breath washins (SBW) by using tracers of different diffusivity and varied the time spent in microgravity (microG) before the start of the tests to look for time-dependent effects. SF(6) and CH(4) phase III slopes decreased by 35 and 26%, respectively, in microG compared with 1 G (P < 0.05), and the slope difference between gases disappeared. There was no effect of time in microG, suggesting that neither the hypergravity period preceding microG nor the time spent in microG affected gas mixing at volumes near functional residual capacity. In previous studies using SF(6) and He (Lauzon A-M, Prisk GK, Elliott AR, Verbanck S, Paiva M, and West JB. J Appl Physiol 82: 859-865, 1997), the vital capacity SBW showed an increase in slope difference between gases in transient microG, the opposite of the decrease in sustained microG. In contrast, tidal volume SBW showed a decrease in slope difference in both microG conditions. Because it is only the behavior of the more diffusive gas that differed between maneuvers and microG conditions, we speculate that, in the previous vital capacity SBW, the hypergravity period preceding the test in transient microG provoked conformational changes at low lung volumes near the acinar entrance.

  17. Analysis of tidal breathing flow volume loops for automated lung-function diagnosis in infants.

    PubMed

    Leonhardt, Steffen; Ahrens, Peter; Kecman, Vojislav

    2010-08-01

    Lung-function analysis in the age group below 5 years has not yet found its way into clinical routine. One possible candidate for routine lung testing in this age group is the analysis of tidal breathing flow-volume (TBFV) loops, a technique that has not yet proven to be capable of detecting obstructive and other lung disorders at an early stage. We present a new set of mathematical features useful to analyze TBFV loops. These new features attempt to describe more complex properties of the loops, thus imitating medical judgment of the curves (e.g., "round," "triangular," etc.) in a "linguistic" manner. Furthermore, we introduce support vector machines (SVMs) as a method for automated classification of diseases. In a retrospective clinical trial on 195 spontaneously breathing infants aged 3 to 24 months, the discriminant power of individual features and the overall diagnostic performance of SVMs is investigated and compared with the results obtained with traditional Bayes' classifiers. We demonstrate that the proposed new features perform better in all examined disease groups and that depending on the disease, the classification error can be reduced by up to 50%. We conclude that TBFV loops may have a much stronger discriminant power than previously thought.

  18. Methods for Assessing Expiratory Flow Limitation during Tidal Breathing in COPD Patients.

    PubMed

    Koulouris, Nickolaos G; Kaltsakas, Georgios; Palamidas, Anastasios F; Gennimata, Sofia-Antiopi

    2012-01-01

    Patients with severe COPD often exhale along the same flow-volume curve during quite breathing as during forced expiratory vital capacity manoeuvre, and this has been taken as indicating expiratory flow limitation at rest (EFL(T)). Therefore, EFL(T), namely, attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow. EFL(T) leads to small airway injury and promotes dynamic pulmonary hyperinflation with concurrent dyspnoea and exercise limitation. In fact, EFL(T) occurs commonly in COPD patients (mainly in GOLD III and IV stage) in whom the latter symptoms are common. The existing up-to-date physiological methods for assessing expiratory flow limitation (EFL(T)) are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure (NEP) has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, non invasive, most practical, and accurate new technique.

  19. Methods for Assessing Expiratory Flow Limitation during Tidal Breathing in COPD Patients.

    PubMed

    Koulouris, Nickolaos G; Kaltsakas, Georgios; Palamidas, Anastasios F; Gennimata, Sofia-Antiopi

    2012-01-01

    Patients with severe COPD often exhale along the same flow-volume curve during quite breathing as during forced expiratory vital capacity manoeuvre, and this has been taken as indicating expiratory flow limitation at rest (EFL(T)). Therefore, EFL(T), namely, attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow. EFL(T) leads to small airway injury and promotes dynamic pulmonary hyperinflation with concurrent dyspnoea and exercise limitation. In fact, EFL(T) occurs commonly in COPD patients (mainly in GOLD III and IV stage) in whom the latter symptoms are common. The existing up-to-date physiological methods for assessing expiratory flow limitation (EFL(T)) are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure (NEP) has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, non invasive, most practical, and accurate new technique. PMID:23008769

  20. Controlled breathing protocols probe human autonomic cardiovascular rhythms

    NASA Technical Reports Server (NTRS)

    Cooke, W. H.; Cox, J. F.; Diedrich, A. M.; Taylor, J. A.; Beightol, L. A.; Ames, J. E. 4th; Hoag, J. B.; Seidel, H.; Eckberg, D. L.

    1998-01-01

    The purpose of this study was to determine how breathing protocols requiring varying degrees of control affect cardiovascular dynamics. We measured inspiratory volume, end-tidal CO2, R-R interval, and arterial pressure spectral power in 10 volunteers who followed the following 5 breathing protocols: 1) uncontrolled breathing for 5 min; 2) stepwise frequency breathing (at 0.3, 0.25, 0.2, 0.15, 0.1, and 0.05 Hz for 2 min each); 3) stepwise frequency breathing as above, but with prescribed tidal volumes; 4) random-frequency breathing (approximately 0.5-0.05 Hz) for 6 min; and 5) fixed-frequency breathing (0.25 Hz) for 5 min. During stepwise breathing, R-R interval and arterial pressure spectral power increased as breathing frequency decreased. Control of inspired volume reduced R-R interval spectral power during 0.1 Hz breathing (P < 0.05). Stepwise and random-breathing protocols yielded comparable coherence and transfer functions between respiration and R-R intervals and systolic pressure and R-R intervals. Random- and fixed-frequency breathing reduced end-tidal CO2 modestly (P < 0.05). Our data suggest that stringent tidal volume control attenuates low-frequency R-R interval oscillations and that fixed- and random-rate breathing may decrease CO2 chemoreceptor stimulation. We conclude that autonomic rhythms measured during different breathing protocols have much in common but that a stepwise protocol without stringent control of inspired volume may allow for the most efficient assessment of short-term respiratory-mediated autonomic oscillations.

  1. Tidal breathing parameters in young children: comparison of measurement by respiratory inductance plethysmography to a facemask pneumotachograph system.

    PubMed

    Manczur, T; Greenough, A; Hooper, R; Allen, K; Latham, S; Price, J F; Rafferty, G F

    1999-12-01

    The ratio of expiratory time at tidal peak flow to total expiratory time (t(ptef)/t(e)) correlates with conventional measures of airway obstruction. It is usually assessed using a facemask and pneumotachograph system which may be poorly tolerated in young children and hence limits the usefulness of this technique. We therefore determined in young asthmatic children the accuracy of t(ptef)/t(e), using an uncalibrated respiratory inductance plethysmograph (RIP), and compared the results with those from a facemask-pneumotachograph system. We also assessed whether age influenced the agreement between measurements using the two devices. Forty-seven children aged between 1 month and 12 years were recruited: 39 were inpatients recovering from an acute wheezy episode, and 8 were recruited from the asthma clinic. All were receiving bronchodilators. Tidal breathing parameters t(ptef)/t(e), the duty cycle (t(i)/t(tot)), and respiratory rate were initially measured using the Respitrace alone and then simultaneously with both the Respitrace and the facemask-pneumotachograph system. Eight children did not tolerate the facemask, and in two others it was impossible to analyze the Respitrace trace due to artefacts. In the remaining 37 children, the reliability coefficients and coefficients of variation of the two techniques were similar. Similar values of t(i)/t(tot) and respiratory rate were obtained using the two devices. The mean t(ptef)/t(e) obtained using the Respitrace was lower than with the facemask-pneumotachograph system (P < 0.01), although this was age group-dependent (P < 0.05), as the difference was less apparent in the 1 to 2-year-old children than in other age groups. Application of the facemask-pneumotachograph system did not significantly influence the results obtained using the Respitrace. We conclude that uncalibrated respiratory inductance plethysmography can measure tidal breathing parameters as reliably as a facemask-pneumotachograph system in young asthmatic

  2. Keep Kids' Mouths Healthy: Brush 2min2X

    MedlinePlus

    ... Kids’ Teeth Teeth Helpful Resources Links Keep Kids’ Mouths Healthy Roll over or click the time line below for healthy mouth information. Email Link Kids' Care Timeline Brush 2min2x - ...

  3. A critical assessment of uncalibrated respiratory inductance plethysmography (Respitrace) for the measurement of tidal breathing parameters in newborns and infants.

    PubMed

    Jackson, E; Stocks, J; Pilgrim, L; Dundas, I; Dezateux, C

    1995-08-01

    We have compared results obtained with an uncalibrated respiratory inductance plethysmograph (RIP) with those of a face mask and pneumotachograph (PNT) for the computerized measurement of the time to reach peak tidal expiratory flow as a ratio of total expiratory time (tPTEF:tE). Simultaneous measurements were made in 32 healthy neonates aged 0-3 weeks, 35 healthy infants aged 5-82 weeks, and 28 infants aged 15-94 weeks with physician diagnosed recurrent wheeze. The group mean (+/- SD) values of tPTEF:TE determined using a PNT were 0.455 (+/- 0.129), 0.263 (+/- 0.077), and 0.232 (+/- 0.089) for the neonates, healthy infants and infants with recurrent wheeze respectively. RIP gave mean (+/- SD) values that were 0.055 (+/- 0.044) and 0.025 (+/- 0.104) lower than the PNT in healthy neonates and infants with recurrent wheeze respectively; RIP values were 0.002 (+/- 0.073) higher in the healthy infants over 4 weeks of age than measurements by PNT. Although the difference between the two measurements was not related to the thoracoabdominal phase angle, as measured from Lissajous figures, examination of the RIP ribcage and abdominal signals revealed that many healthy subjects, while appearing clinically in phase, had ribcage and abdominal signals that differed markedly from each other in terms of convexity/concavity during early expiration. This may explain the lack of agreement between the two methods. We conclude that uncalibrated RIP should be used with caution for the determination of tPTEF:tE, even in subjects whose ribcage and abdomen appear to move synchronously. The measurement of tPTEF:tE did not differentiate between the healthy infants and infants with recurrent wheezing.

  4. Bad Breath

    MedlinePlus

    ... habits, like brushing and flossing regularly, help fight bad breath. Mouthwashes, mints or chewing gum may make your breath fresher. If you have an underlying disorder, treating it may help eliminate the breath odor.

  5. Breathing Problems

    MedlinePlus

    ... re not getting enough air. Sometimes mild breathing problems are from a stuffy nose or hard exercise. ... emphysema or pneumonia cause breathing difficulties. So can problems with your trachea or bronchi, which are part ...

  6. Breath-by-breath measurement of particle deposition in the lung of spontaneously breathing rats.

    PubMed

    Karrasch, S; Eder, G; Bolle, I; Tsuda, A; Schulz, H

    2009-10-01

    A number of deposition models for humans, as well as experimental animals, have been described. However, no breath-by-breath deposition measurement in rats has been reported to date. The objective of this study is to determine lung deposition of micrometer-sized particles as a function of breathing parameters in the adult rat lung. A new aerosol photometry system was designed to measure deposition of nonhygroscopic, 2-mum sebacate particles in anesthetized, intubated, and spontaneously breathing 90-day-old Wistar-Kyoto rats placed in a size-adjusted body plethysmograph box. Instrumental dead space of the system was minimized down to 310 microl (i.e., approximately 20% of respiratory dead space). The system allows continuous monitoring of particle concentration in the respired volume. Breathing parameters, such as respiratory rate (f), tidal volume (Vt), as well as inspiration/expiration times, were also monitored at different levels of anesthesia. The results showed that Vt typically varied between 1.5 and 4.0 ml for regular breathing and between 4.0 and 10.0 ml for single-sigh breaths; f ranged from 40 to 200 breaths/min. Corresponding deposition values varied between 5 and 50%, depending on breath-by-breath breathing patterns. The best fit of deposition (D) was achieved by a bilinear function of Vt and f and found to be D = 11.0 - 0.09.f + 3.75.Vt. We conclude that our approach provides more realistic conditions for the measurement of deposition than conventional models using ventilated animals and allows us to analyze the correlation between breath-specific deposition and spontaneous breathing patterns.

  7. Syllable-Related Breathing in Infants in the Second Year of Life

    ERIC Educational Resources Information Center

    Parham, Douglas F.; Buder, Eugene H.; Oller, D. Kimbrough; Boliek, Carol A.

    2011-01-01

    Purpose: This study explored whether breathing behaviors of infants within the 2nd year of life differ between tidal breathing and breathing supporting single unarticulated syllables and canonical/articulated syllables. Method: Vocalizations and breathing kinematics of 9 infants between 53 and 90 weeks of age were recorded. A strict selection…

  8. Kidney motion during free breathing and breath hold for MR-guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Stam, Mette K.; van Vulpen, Marco; Barendrecht, Maurits M.; Zonnenberg, Bernard A.; Intven, Martijn; Crijns, Sjoerd P. M.; Lagendijk, Jan J. W.; Raaymakers, Bas W.

    2013-04-01

    Current treatments for renal cell carcinoma have a high complication rate due to the invasiveness of the treatment. With the MRI-linac it may be possible to treat renal tumours non-invasively with high-precision radiotherapy. This is expected to reduce complications. To deliver a static dose distribution, radiation gating will be used. In this study the reproducibility and efficiency of free breathing gating and a breath hold treatment of the kidney was investigated. For 15 patients with a renal lesion the kidney motion during 2 min of free breathing and 10 consecutive expiration breath holds was studied with 2D cine MRI. The variability in kidney expiration position and treatment efficiency for gating windows of 1 to 20 mm was measured for both breathing patterns. Additionally the time trend in free breathing and the variation in expiration breath hold kidney position with baseline shift correction was determined. In 80% of the patients the variation in expiration position during free breathing is smaller than 2 mm. No clinically relevant time trends were detected. The variation in expiration breath hold is for all patients larger than the free breathing expiration variation. Gating on free breathing is, for gating windows of 1 to 5 mm more efficient than breath hold without baseline correction. When applying a baseline correction to the breath hold it increases the treatment efficiency. The kidney position is more reproducible in expiration free breathing than non-guided expiration breath hold. For small gating windows it is also more time efficient. Since free breathing also seems more comfortable for the patients it is the preferred breathing pattern for MRI-Linac treatments of the kidney.

  9. Bad Breath

    MedlinePlus

    ... hygiene leads to bad breath because when food particles are left in your mouth, they can rot ... Flossing once a day helps get rid of particles wedged between your teeth. Also, visit your dentist ...

  10. Psychophysiological effects of breathing instructions for stress management.

    PubMed

    Conrad, Ansgar; Müller, Anett; Doberenz, Sigrun; Kim, Sunyoung; Meuret, Alicia E; Wollburg, Eileen; Roth, Walton T

    2007-06-01

    Stressed and tense individuals often are recommended to change the way they breathe. However, psychophysiological effects of breathing instructions on respiration are rarely measured. We tested the immediate effects of short and simple breathing instructions in 13 people seeking treatment for panic disorder, 15 people complaining of daily tension, and 15 controls. Participants underwent a 3-hour laboratory session during which instructions to direct attention to breathing and anti-hyperventilation instructions to breathe more slowly, shallowly, or both were given. Respiratory, cardiac, and electrodermal measures were recorded. The anti-hyperventilation instructions failed to raise end-tidal pCO(2) above initial baseline levels for any of the groups because changes in respiratory rate were compensated for by changes in tidal volume and vice versa. Paying attention to breathing significantly reduced respiratory rate and decreased tidal volume instability compared to the other instructions. Shallow breathing made all groups more anxious than did other instructions. Heart rate and skin conductance were not differentially affected by instructions. We conclude that simple and short instructions to alter breathing do not change respiratory or autonomic measures in the direction of relaxation, except for attention to breathing, which increases respiratory stability. To understand the results of breathing instructions for stress and anxiety management, respiration needs to be monitored physiologically.

  11. Immediate effects of breath holding maneuvers onto composition of exhaled breath.

    PubMed

    Sukul, Pritam; Trefz, Phillip; Schubert, Jochen K; Miekisch, Wolfram

    2014-09-01

    Rapid concentration changes due to physiological or pathophysiological effects rather than appearance of unique disease biomarkers are important for clinical application of breath research. Simple maneuvers such as breath holding may significantly affect breath biomarker concentrations. In this study, exhaled volatile organic compound (VOC) concentrations were assessed in real time before and after different breath holding maneuvers. Continuous breath-resolved measurements (PTR-ToF-MS-8000) were performed in 31 healthy human subjects in a side-stream sampling mode. After 1 min of tidal breathing participants held their breath for 10, 20, 40, 60 s and as long as possible. Afterwards they continued to breathe normally for another minute. VOC profiles could be monitored in real time by assigning online PTR-ToF-MS data to alveolar or inspired phases of breath. Sudden and profound changes of exhaled VOC concentrations were recorded after different breath holding maneuvers. VOC concentrations returned to base line levels 10-20 s after breath holding. Breath holding induced concentration changes depended on physico-chemical properties of the substances. When substance concentrations were normalized onto end-tidal CO2 content, variation of acetone concentrations decreased, whereas variations of isoprene concentrations were not affected. As the effects of breathing patterns on exhaled substance concentrations depend on individual substance properties, sampling procedures have to be validated for each compound by means of appropriate real-time analysis. Normalization of exhaled concentrations onto exhaled CO2 is only valid for substances having similar physico-chemical properties as CO2.

  12. Tidal Energy.

    ERIC Educational Resources Information Center

    Impact of Science on Society, 1987

    1987-01-01

    States that tidal power projects are feasible in a relatively limited number of locations around the world. Claims that together they could theoretically produce the energy equivalent to more than one million barrels of oil per year. (TW)

  13. How to breathe when you are short of breath

    MedlinePlus

    Pursed lip breathing; COPD - pursed lip breathing; Emphysema - pursed lip breathing; Chronic bronchitis - pursed lip breathing; Pulmonary fibrosis - pursed lip breathing; Interstitial lung disease - pursed lip breathing; Hypoxia - pursed lip breathing; ...

  14. Tidal Meanders

    NASA Astrophysics Data System (ADS)

    Marani, M.; Lanzoni, S.; Zandolin, D.; Seminara, S.; Rinaldo, A.

    Observational evidence is presented on the geometry of meandering tidal channels evolved within coastal wetlands characterized by different tidal, hydrodynamic, to- pographic, vegetational and ecological features. New insight is provided on the ge- ometrical properties of tidal meanders, with possible dynamic implications on their evolution. In particular, it is shown that large spatial gradients of leading flow rates induce important spatial variabilities of meander wavelengths and widths, while their ratio remains remarkably constant in the range of scales of observation. This holds regardless of changes in width and wavelength up to two orders of magnitude. This suggests a locally adapted evolution, involving the morphological adjustment to the chief landforming events driven by local hydrodynamics. The spectral analysis of lo- cal curvatures reveals that Kinoshita's model curve does not fit tidal meanders due to the presence of even harmonics, in particular the second mode. Geometric parameters are constructed that are suitable to detect possible geomorphic signatures of the tran- sitions from ebb- to flood-dominated hydrodynamics, here related to the skewness of the tidal meander. Trends in skewness, however, prove elusive to measure and fail to show detectable patterns. We also study comparatively the spatial patterns of evolu- tion of the ratios of channel width to depth, and the ratio of width to local radius of curvature. Interestingly, the latter ratio exhibits consistency despite sharp differences in channel incision. Since the degree of incision, epitomized by the width-to-depth ratio, responds to the relevant erosion and migrations mechanisms and is much sen- sitive to vegetation and sediment properties, it is noticeable that we observe a great variety of landscape carving modes and yet recurrent planar features like constant width/curvature and wavelength/width ratios.

  15. What Controls Your Breathing?

    MedlinePlus

    ... To a limited degree, you can change your breathing rate, such as by breathing faster or holding your ... oxygen levels in your blood and change your breathing rate as needed. Sensors in the airways detect lung ...

  16. Breath alcohol test

    MedlinePlus

    Alcohol test - breath ... There are various brands of breath alcohol tests. Each one uses a different method to test the level of alcohol in the breath. The machine may be electronic or manual. One ...

  17. Breath-Holding Spells

    MedlinePlus

    ... less than a minute before a child regains consciousness and resumes breathing normally. Breath-holding spells can ... spells cause kids to stop breathing and lose consciousness for up to a minute. In the most ...

  18. Voluntary control of breathing does not alter vagal modulation of heart rate

    NASA Technical Reports Server (NTRS)

    Patwardhan, A. R.; Evans, J. M.; Bruce, E. N.; Eckberg, D. L.; Knapp, C. F.

    1995-01-01

    Variations in respiratory pattern influence the heart rate spectrum. It has been suggested, hence, that metronomic respiration should be used to correctly assess vagal modulation of heart rate by using spectral analysis. On the other hand, breathing to a metronome has been reported to increase heart rate spectral power in the high- or respiratory frequency region; this finding has led to the suggestion that metronomic respiration enhances vagal tone or alters vagal modulation of heart rate. To investigate whether metronomic breathing complicates the interpretation of heart rate spectra by altering vagal modulation, we recorded the electrocardiogram and respiration from eight volunteers during three breathing trials of 10 min each: 1) spontaneous breathing (mean rate of 14.4 breaths/min); 2) breathing to a metronome at the rate of 15, 18, and 21 breaths/min for 2, 6, and 2 min, respectively; and 3) breathing to a metronome at the rate of 18 breaths/min for 10 min. Data were also collected from eight volunteers who breathed spontaneously for 20 min and breathed metronomically at each subject's mean spontaneous breathing frequency for 20 min. Results from the three 10-min breathing trials showed that heart rate power in the respiratory frequency region was smaller during metronomic breathing than during spontaneous breathing. This decrease could be explained fully by the higher breathing frequencies used during trials 2 and 3 of metronomic breathing. When the subjects breathed metronomically at each subject's mean breathing frequency, the heart rate powers during metronomic breathing were similar to those during spontaneous breathing. Our results suggest that vagal modulation of heart rate is not altered and vagal tone is not enhanced during metronomic breathing.

  19. Breathing difficulty - lying down

    MedlinePlus

    ... Paroxysmal nocturnal dyspnea; PND; Difficulty breathing while lying down; Orthopnea ... does not directly cause difficulty breathing while lying down but often worsens other conditions that lead to ...

  20. Measurement of end-tidal PCO2 and PO2.

    PubMed

    Gardner, W

    1994-06-01

    This article describes the basic principles of the measurement of end-tidal carbon dioxide (CO2) and oxygen (O2) in humans. The description includes definitions of the major parameters of breathing (e.g., the composition of atmospheric air, arterial and venous blood; metabolism; lung capacity; volumetric measures of tidal volume, minute volume, and respiration frequency; pH regulation and cerebral acidity; barometric pressure and the partial pressures of CO2 and O2), the basic anatomical features of breathing, the means by which gases are exchanged between the lungs and blood, the techniques used in the measurement of respiratory variables, and the interpretation of these measurements. PMID:7918749

  1. Tidal power in Argentina

    SciTech Connect

    Aisiks, E.G.

    1993-03-01

    This presentation describes the tidal power potential of Argentina and the current status of its utilization. The topics of the presentation include tidal power potential, electric production of the region and the Argentine share of production and consumption, conventional hydroelectric potential, economic feasibility of tidal power production, and the general design and feasibility of a tidal power plant planned for the San Jose Gulf.

  2. Additional work of breathing imposed by endotracheal tubes, breathing circuits, and intensive care ventilators.

    PubMed

    Bersten, A D; Rutten, A J; Vedig, A E; Skowronski, G A

    1989-07-01

    A disadvantage of spontaneous breathing through an endotracheal tube (ETT) and connector attached to a breathing circuit and/or ventilator (breathing device) is an increase in the work of breathing. The work of breathing associated with ETT of 6 to 9-mm diameter and eight breathing devices was determined, using a lung simulator to mimic spontaneous inspiration at flow rates of 20 to 100 L/min and a tidal volume of 500 ml, at both zero end-expiratory pressure (ZEEP) and 10 cm H2O continuous positive airway pressure (CPAP). Work associated with the breathing devices alone (WCIR) ranged from -0.002 kg.m/L (Servo 900-C ventilator, 7-mm ETT, 20 L/min, ZEEP) to 0.1 kg.m/L (continuous flow circuit, 7-mm ETT, 100 L/min, CPAP), the latter representing 196% of the work of normal breathing. When the devices were attached to ETT, total apparatus work (WAPP) ranged from 0.009 kg.m/L (Mapleson-D circuit, 9-mm ETT, 20 L/min, ZEEP) to 0.25 kg.m/L (Drager EV-A, 6-mm ETT, 100 L/min, ZEEP), the latter representing 490% of the work of normal breathing. This additional work imposed by the ETT varied considerably among devices. Spontaneous breathing through modern ventilators, circuits and ETT imposes a burden of increased work, most of which is associated with the presence of the ETT and connector. Whether this burden represents an impediment to the weaning patient, or has training value for the ultimate resumption of unassisted spontaneous ventilation, remains to be determined.

  3. Variability of the breathing pattern before and after extubation.

    PubMed

    Krieger, B P; Chediak, A; Gazeroglu, H B; Bizousky, F P; Feinerman, D

    1988-04-01

    A stable breathing pattern during unassisted ventilation through an endotracheal tube (ETT) prior to extubation is an important factor in determining whether a patient can be successfully extubated. Proper interpretation of changes in the breathing pattern requires knowledge of the normal variability of the breathing pattern in critically ill, intubated patients. To establish these guidelines, 50 spontaneously breathing patients who were being weaned from mechanical ventilation were monitored with respiratory inductive plethysmography for one hour immediately prior to and following successful extubation. Immediately after extubation, respiratory rate (f), tidal volume (VT), minute ventilation, and mean inspiratory flow increased slightly. By 30 minutes postextubation, these parameters were similar to preextubation values. There was no significant change in variability of f or VT. Although the breathing pattern of these relatively stable, intensive care patients differed from values of normal ambulatory subjects, values were similar in the preextubation and postextubation periods.

  4. Minimizing Shortness of Breath

    MedlinePlus

    ... Top Doctors in the Nation Departments & Divisions Home Health Insights Stress & Relaxation Breathing and Relaxation Minimizing Shortness of Breath ... Management Assess Your Stress Coping Strategies Identifying ... & Programs Health Insights Doctors & Departments Research & Science Education & Training Make ...

  5. Breathing and Relaxation

    MedlinePlus

    ... Top Doctors in the Nation Departments & Divisions Home Health Insights Stress & Relaxation Breathing and Relaxation Breathing and Relaxation Make ... Management Assess Your Stress Coping Strategies Identifying ... & Programs Health Insights Doctors & Departments Research & Science Education & Training Make ...

  6. Hypoxia switches episodic breathing to singlet breathing in red-eared slider turtles (Trachemys scripta) via a tropisetron-sensitive mechanism

    PubMed Central

    Johnson, Stephen M.; Krisp, Ashley R.; Bartman, Michelle E.

    2015-01-01

    Hypoxia-induced changes in the chelonian breathing pattern are poorly understood. Thus, breathing was measured in freely swimming adult red-eared slider turtles breathing air prior to breathing nitrogen for 4 h. Ventilation increased 10-fold within 10 min due to increased breath frequency and tidal volume. Breaths/episode decreased by ~50% within after 1 h of hypoxia while the number of singlet breaths increased from 3.1 ± 1.6 singlets/h to a maximum of 66.1 ± 23.5 singlets/h. Expiratory and inspiratory duration increased during hypoxia. For doublet and triplet breaths, expiratory duration increased during the first breath only, while inspiratory duration increased for all breaths. Tropisetron (5-HT3 receptor antagonist, 5 mg/kg) administration prior to hypoxia attenuated the hypoxia-induced increase in singlet breath frequency. Along with results from previous in vitro studies, this study suggests that 5-HT3 receptor activation may be required for the hypoxia-induced increase in singlet breathing pattern in red-eared slider turtles. PMID:25543027

  7. A Systematic Approach to Multiple Breath Nitrogen Washout Test Quality

    PubMed Central

    Klingel, Michelle; Pizarro, Maria Ester; Hall, Graham L.; Ramsey, Kathryn; Foong, Rachel; Saunders, Clare; Robinson, Paul D.; Webster, Hailey; Hardaker, Kate; Kane, Mica; Ratjen, Felix

    2016-01-01

    Background Accurate estimates of multiple breath washout (MBW) outcomes require correct operation of the device, appropriate distraction of the subject to ensure they breathe in a manner representative of their relaxed tidal breathing pattern, and appropriate interpretation of the acquired data. Based on available recommendations for an acceptable MBW test, we aimed to develop a protocol to systematically evaluate MBW measurements based on these criteria. Methods 50 MBW test occasions were systematically reviewed for technical elements and whether the breathing pattern was representative of relaxed tidal breathing by an experienced MBW operator. The impact of qualitative and quantitative criteria on inter-observer agreement was assessed across eight MBW operators (n = 20 test occasions, compared using a Kappa statistic). Results Using qualitative criteria, 46/168 trials were rejected: 16.6% were technically unacceptable and 10.7% were excluded due to inappropriate breathing pattern. Reviewer agreement was good using qualitative criteria and further improved with quantitative criteria from (κ = 0.53–0.83%) to (κ 0.73–0.97%), but at the cost of exclusion of further test occasions in this retrospective data analysis. Conclusions The application of the systematic review improved inter-observer agreement but did not affect reported MBW outcomes. PMID:27304432

  8. Improving estimation of cardiac vagal tone during spontaneous breathing using a paced breathing calibration.

    PubMed

    Wilhelm, Frank H; Grossman, Paul; Coyle, Michael A

    2004-01-01

    Respiratory sinus arrhythmia (RSA) is a commonly employed non-invasive measure of cardiac vagal control. It has been demonstrated that respiratory parameters such as tidal volume and respiratory frequency can change RSA without altering tonic vagal activity. Thus, within-individual comparisons of cardiac vagal control across different behavioral tasks might benefit from an adjustment for respiratory confounds. We tested an adjustment method using transfer function analysis and paced breathing at 3 different respiratory frequencies as the basis for regressing out respiratory related RSA changes in a task where breathing was not controlled. Electrocardiogram and calibrated respiration were recorded with the LifeShirt system from 15 young adult participants. Time series of RR intervals and lung volume change were computed and the respiration-to-RR-interval transfer-function magnitude (RSA-TF, in ms/liter) estimated. Mean (SD) of RSA-TF was 142 (68) at 9 breaths/min, 78 (52) at 13.5 breaths/min, 57 (43) at 18 breaths/min, and 121 (56) during baseline, with a respiratory frequency of 12.5 (3.8) breaths/min. At baseline, measured and predicted RSA-TF values (mean 94 +/- 82) differed significantly and correlated only moderately (r = 0.67). Factors contributing to a less than perfect correlation included slightly elevated subjective anxiety levels and hyperventilation during paced breathing, both of which may have affected cardiac vagal tone. This study demonstrates a novel procedure for computing a respiratory unrelated RSA index. Results provide some support for the utility of this adjustment method for improving the estimation of cardiac vagal tone from RSA, but also indicate that the paced breathing procedure may need to be further refined.

  9. Understanding the rhythm of breathing: so near yet so far

    PubMed Central

    Feldman, Jack L.; Del Negro, Christopher A.; Gray, Paul A.

    2013-01-01

    , responding rapidly (in less than one second) and with considerable precision, over an order of magnitude in metabolic demand for O2 (~0.25 to ~5 liters of O2/min). Breathing does indeed persist! Finally, breathing is genetically determined to work at birth, with a well-defined developmental program underlying a neuroanatomical organization with apparent segregation of function, i.e., rhythmogenesis is separate from motor pattern (burst shape and coordination) generation. Importantly, single human gene mutations can affect breathing, and several neurodegenerative disorders compromise breathing by direct effects on brainstem respiratory circuits (See below). PMID:23121137

  10. Air-breathing adaptation in a marine Devonian lungfish.

    PubMed

    Clement, Alice M; Long, John A

    2010-08-23

    Recent discoveries of tetrapod trackways in 395 Myr old tidal zone deposits of Poland (Niedźwiedzki et al. 2010 Nature 463, 43-48 (doi:10.1038/nature.08623)) indicate that vertebrates had already ventured out of the water and might already have developed some air-breathing capacity by the Middle Devonian. Air-breathing in lungfishes is not considered to be a shared specialization with tetrapods, but evolved independently. Air-breathing in lungfishes has been postulated as starting in Middle Devonian times (ca 385 Ma) in freshwater habitats, based on a set of skeletal characters involved in air-breathing in extant lungfishes. New discoveries described herein of the lungfish Rhinodipterus from marine limestones of Australia identifies the node in dipnoan phylogeny where air-breathing begins, and confirms that lungfishes living in marine habitats had also developed specializations to breathe air by the start of the Late Devonian (ca 375 Ma). While invasion of freshwater habitats from the marine realm was previously suggested to be the prime cause of aerial respiration developing in lungfishes, we believe that global decline in oxygen levels during the Middle Devonian combined with higher metabolic costs is a more likely driver of air-breathing ability, which developed in both marine and freshwater lungfishes and tetrapodomorph fishes such as Gogonasus.

  11. Simulated breath waveform control

    NASA Technical Reports Server (NTRS)

    Bartlett, R. G.; Hendricks, C. M.; Morison, W. B.

    1972-01-01

    Subsystem was developed which provides twelve waveform controls to breath drive mechanism. Twelve position, magnetically actuated rotary switch is connected to one end of crankshaft drive, such that it makes one complete revolution for each simulated breath. Connections with common wired point are included in modifications made to standard motor speed controller.

  12. From breathing to respiration.

    PubMed

    Fitting, Jean-William

    2015-01-01

    The purpose of breathing remained an enigma for a long time. The Hippocratic school described breathing patterns but did not associate breathing with the lungs. Empedocles and Plato postulated that breathing was linked to the passage of air through pores of the skin. This was refuted by Aristotle who believed that the role of breathing was to cool the heart. In Alexandria, breakthroughs were accomplished in the anatomy and physiology of the respiratory system. Later, Galen proposed an accurate description of the respiratory muscles and the mechanics of breathing. However, his heart-lung model was hampered by the traditional view of two non-communicating vascular systems - veins and arteries. After a period of stagnation in the Middle Ages, knowledge progressed with the discovery of pulmonary circulation. The comprehension of the purpose of breathing progressed by steps thanks to Boyle and Mayow among others, and culminated with the contribution of Priestley and the discovery of oxygen by Lavoisier. Only then was breathing recognized as fulfilling the purpose of respiration, or gas exchange. A century later, a controversy emerged concerning the active or passive transfer of oxygen from alveoli to the blood. August and Marie Krogh settled the dispute, showing that passive diffusion was sufficient to meet the oxygen needs.

  13. From breathing to respiration.

    PubMed

    Fitting, Jean-William

    2015-01-01

    The purpose of breathing remained an enigma for a long time. The Hippocratic school described breathing patterns but did not associate breathing with the lungs. Empedocles and Plato postulated that breathing was linked to the passage of air through pores of the skin. This was refuted by Aristotle who believed that the role of breathing was to cool the heart. In Alexandria, breakthroughs were accomplished in the anatomy and physiology of the respiratory system. Later, Galen proposed an accurate description of the respiratory muscles and the mechanics of breathing. However, his heart-lung model was hampered by the traditional view of two non-communicating vascular systems - veins and arteries. After a period of stagnation in the Middle Ages, knowledge progressed with the discovery of pulmonary circulation. The comprehension of the purpose of breathing progressed by steps thanks to Boyle and Mayow among others, and culminated with the contribution of Priestley and the discovery of oxygen by Lavoisier. Only then was breathing recognized as fulfilling the purpose of respiration, or gas exchange. A century later, a controversy emerged concerning the active or passive transfer of oxygen from alveoli to the blood. August and Marie Krogh settled the dispute, showing that passive diffusion was sufficient to meet the oxygen needs. PMID:25532022

  14. Automatic electrical stimulation of abdominal wall muscles increases tidal volume and cough peak flow in tetraplegia.

    PubMed

    Gollee, H; Hunt, K J; Allan, D B; Fraser, M H; McLean, A N

    2008-01-01

    Paralysis of the respiratory muscles in people with tetraplegia affects their ability to breathe and contributes to respiratory complications. Surface functional electrical stimulation (FES) of abdominal wall muscles can be used to increase tidal volume (V_{T}) and improve cough peak flow (CPF) in tetraplegic subjects who are able to breathe spontaneously. This study aims to evaluate the feasibility and effectiveness of a novel abdominal FES system which generates stimulation automatically, synchronised with the subjects' voluntary breathing activity. Four subjects with complete tetraplegia (C4-C6), breathing spontaneously, were recruited. The automatic stimulation system ensured that consistent stimulation was achieved. We compared spirometry during unassisted and FES-assisted quiet breathing and coughing, and measured the effect of stimulation on end-tidal CO_2 (EtCO_2) during quiet breathing. The system dependably recognised spontaneous respiratory effort, stimulating appropriately, and was well tolerated by patients. Significant increases in V_T during quiet breathing (range 0.05-0.23 L) and in CPF (range 0.04-0.49 L/s) were observed. Respiratory rate during quiet breathing decreased in all subjects when stimulated, whereas minute ventilation increased by 1.05-2.07 L/min. The changes in EtCO_2 were inconclusive. The automatic stimulation system augmented spontaneous breathing and coughing in tetraplegic patients and may provide a potential means of respiratory support for tetraplegic patients with reduced respiratory capacity.

  15. Tidal Power in France

    SciTech Connect

    Frau, J.P. )

    1993-03-01

    This presentation discusses the tidal power resource of France and the successes of the La Rance Plant. The topics of the presentation include power generation, adaptation of output to grid requirements, plant installation, environmental factors, La Rance success, and a review of major world wide tidal energy projects in the UK, Canada, South Korea, India, and Argentina.

  16. TIDEV: Tidal Evolution package

    NASA Astrophysics Data System (ADS)

    Cuartas-Restrepo, P.; Melita, M.; Zuluaga, J.; Portilla, B.; Sucerquia, M.; Miloni, O.

    2016-09-01

    TIDEV (Tidal Evolution package) calculates the evolution of rotation for tidally interacting bodies using Efroimsky-Makarov-Williams (EMW) formalism. The package integrates tidal evolution equations and computes the rotational and dynamical evolution of a planet under tidal and triaxial torques. TIDEV accounts for the perturbative effects due to the presence of the other planets in the system, especially the secular variations of the eccentricity. Bulk parameters include the mass and radius of the planet (and those of the other planets involved in the integration), the size and mass of the host star, the Maxwell time and Andrade's parameter. TIDEV also calculates the time scale that a planet takes to be tidally locked as well as the periods of rotation reached at the end of the spin-orbit evolution.

  17. Shortness-of-Breath

    MedlinePlus

    ... can lead to shortness of breath include anxiety, panic attacks, anemia and even constipation. The experience of shortness ... are used to treat patients with anxiety or panic attacks. Other commonly used drugs include bronchodilators to widen ...

  18. Stop, Breathe & Think app.

    PubMed

    Shaw, Natalie

    2014-07-15

    The Stop, Breathe & Think app is free, thanks to underwriting from Tools for Peace, the non-profit organisation that teaches people of all ages how to develop and apply kindness and compassion in their daily lives.

  19. Breath holding spell

    MedlinePlus

    ... such as Riley-Day syndrome or Rett syndrome Iron deficiency anemia A family history of breath holding spells ( ... tests may be done to check for an iron deficiency. Other tests that may be done include: EKG ...

  20. Shortness of Breath

    MedlinePlus

    ... deep breath, which usually results in retention of carbon dioxide and not enough oxygen in blood (obesity hypoventilation ... for anemia), and oximetry or blood oxygen or carbon dioxide levels. Your doctor also may obtain a chest ...

  1. Sevoflurane degradation by soda lime in a circle breathing system.

    PubMed

    Munday, I T; Ward, P M; Foden, N D; Jones, R M; Van Pelt, F N; Kenna, J G

    1996-07-01

    Sevoflurane is degraded by soda lime to a vinyl ether commonly referred to as compound A. We measured the concentration of compound A in the circle breathing system of 31 patients receiving sevoflurane anaesthesia. Inspiratory and expiratory gas samples were analysed using gas chromatography and flame ionisation detection. The end-tidal sevoflurane concentration and soda lime temperature were recorded. The peak compound A concentration ranged between 10 to 32 ppm in the inspiratory limb and 7 to 26 ppm in the expiratory limb. There was a positive correlation between the peak compound A concentration and the end-tidal sevoflurane concentration (r2 = 0.545, p < 0.0001) and the soda lime temperature (r2 = 0.301, p = 0.0014). We conclude that the end-tidal concentration of sevoflurane and the temperature of the soda lime are important variables in determining concentration of compound A in a circle system.

  2. Archosaurian respiration and the pelvic girdle aspiration breathing of crocodyliforms.

    PubMed Central

    Claessens, Leon P. A. M.

    2004-01-01

    Birds and crocodylians, the only living archosaurs, are generally believed to employ pelvic girdle movements as a component of their respiratory mechanism. This in turn provides a phylogenetic basis for inferring that extinct archosaurs, including dinosaurs, also used pelvic girdle breathing. I examined lung ventilation through cineradiography (high-speed X-ray filming) and observed that alligators indeed rotate the pubis to increase tidal volume, but did not observe pelvic girdle movement contributing to lung ventilation in guinea fowl, emus or tinamous, despite extensive soft-tissue motion. Re-examination of fossil archosaurs reveals that pubic rotation evolved in basal crocodyliforms and that pelvic girdle breathing is not a general archosaurian mechanism. The appearance of pelvic aspiration in crocodyliforms is a striking example of the ability of amniotes to increase gas exchange or circumvent constraints on respiration through the evolution of novel accessory breathing mechanisms. PMID:15306317

  3. Slow Breathing and Hypoxic Challenge: Cardiorespiratory Consequences and Their Central Neural Substrates

    PubMed Central

    Critchley, Hugo D.; Nicotra, Alessia; Chiesa, Patrizia A.; Nagai, Yoko; Gray, Marcus A.; Minati, Ludovico; Bernardi, Luciano

    2015-01-01

    Controlled slow breathing (at 6/min, a rate frequently adopted during yoga practice) can benefit cardiovascular function, including responses to hypoxia. We tested the neural substrates of cardiorespiratory control in humans during volitional controlled breathing and hypoxic challenge using functional magnetic resonance imaging (fMRI). Twenty healthy volunteers were scanned during paced (slow and normal rate) breathing and during spontaneous breathing of normoxic and hypoxic (13% inspired O2) air. Cardiovascular and respiratory measures were acquired concurrently, including beat-to-beat blood pressure from a subset of participants (N = 7). Slow breathing was associated with increased tidal ventilatory volume. Induced hypoxia raised heart rate and suppressed heart rate variability. Within the brain, slow breathing activated dorsal pons, periaqueductal grey matter, cerebellum, hypothalamus, thalamus and lateral and anterior insular cortices. Blocks of hypoxia activated mid pons, bilateral amygdalae, anterior insular and occipitotemporal cortices. Interaction between slow breathing and hypoxia was expressed in ventral striatal and frontal polar activity. Across conditions, within brainstem, dorsal medullary and pontine activity correlated with tidal volume and inversely with heart rate. Activity in rostroventral medulla correlated with beat-to-beat blood pressure and heart rate variability. Widespread insula and striatal activity tracked decreases in heart rate, while subregions of insular cortex correlated with momentary increases in tidal volume. Our findings define slow breathing effects on central and cardiovascular responses to hypoxic challenge. They highlight the recruitment of discrete brainstem nuclei to cardiorespiratory control, and the engagement of corticostriatal circuitry in support of physiological responses that accompany breathing regulation during hypoxic challenge. PMID:25973923

  4. Breathing patterns after mid-cervical spinal contusion in rats

    PubMed Central

    Golder, FJ; Fuller, DD; Lovett-Barr, MR; Vinit, S; Resnick, DK; Mitchell, GS

    2011-01-01

    Respiratory failure is the leading cause of death after cervical spinal injury. We hypothesized that incomplete cervical spinal injuries would alter respiratory pattern and initiate plasticity in the neural control of breathing. Further, we hypothesized that the severity of cervical spinal contusion would correlate with changes in breathing pattern. Fourteen days after C4–C5 contusions, respiratory frequency and tidal volume were measured in unanesthetized Sprague Dawley rats in a whole body plethysmograph. Phrenic motor output was monitored in the same rats which were anesthetized, vagotomized, paralyzed and ventilated to eliminate and/or control sensory feedback that could alter breathing patterns. The extent of spinal injury was approximated histologically by measurements of the injury-induced cyst area in transverse sections; cysts ranged from 2 to 28% of spinal cross-sectional area, and had a unilateral bias. In unanesthetized rats, the severity of spinal injury correlated negatively with tidal volume (R2=0.85; p<0.001) and positively with breathing frequency (R2=0.65; p<0.05). Thus, the severity of C4–C5 spinal contusion dictates post-injury breathing pattern. In anesthetized rats, phrenic burst amplitude was decreased on the side of injury, and burst frequency correlated negatively with contusion size (R2=0.51; p<0.05). A strong correlation between unanesthetized breathing pattern and the pattern of phrenic bursts in anesthetized, vagotomized and ventilated rats suggests that changes in respiratory motor output after spinal injury reflect, at least in part, intrinsic neural mechanisms of CNS plasticity initiated by injury. PMID:21683697

  5. Force oscillations simulating breathing maneuvers do not prevent force adaptation.

    PubMed

    Pascoe, Chris; Jiao, Yuekan; Seow, Chun Y; Paré, Peter D; Bossé, Ynuk

    2012-07-01

    Airway inflammation in patients with asthma exposes the airway smooth muscle (ASM) to a variety of spasmogens. These spasmogens increase ASM tone, which can lead to force adaptation. Length oscillations of ASM, which occur in vivo due to breathing maneuvers, can attenuate force adaptation. However, in the presence of tone, the force oscillations required to achieve these length oscillations may be unphysiologic (i.e., magnitude greater than the ones achieved due to the swings in transpulmonary pressure required for breathing). In the present study, we applied force oscillations simulating the tension oscillations experienced by the wall of a fourth-generation airway during tidal breathing with or without deep inspirations (DI) to ASM. The goal was to investigate whether force adaptation occurs in conditions mimicking breathing maneuvers. Tone was induced by carbachol (average, 20 nM), and the force-generating capacity of the ASM was assessed at 5-minute intervals before and after carbachol administration using electrical field stimulations (EFS). The results show that force oscillations applied before the introduction of tone had a small effect on the force produced by EFS (declined to 96.8% [P > 0.05] and 92.3% [P < 0.05] with and without DI, respectively). The tone induced by carbachol transiently decreased after a DI and declined significantly (P < 0.05) due to tidal breathing oscillations (25%). These force oscillations did not prevent force adaptation (gain of force of 11.2 ± 2.2 versus 13.5 ± 2.7 and 11.2 ± 3.0% in static versus dynamic conditions with or without DI, respectively). The lack of effect of simulated breathing maneuvers on force adaptation suggests that this gain in ASM force may occur in vivo and could contribute to the development of airway hyperresponsiveness. PMID:22323367

  6. Theme and variations: amphibious air-breathing intertidal fishes.

    PubMed

    Martin, K L

    2014-03-01

    Over 70 species of intertidal fishes from 12 families breathe air while emerging from water. Amphibious intertidal fishes generally have no specialized air-breathing organ but rely on vascularized mucosae and cutaneous surfaces in air to exchange both oxygen and carbon dioxide. They differ from air-breathing freshwater fishes in morphology, physiology, ecology and behaviour. Air breathing and terrestrial activity are present to varying degrees in intertidal fish species, correlated with the tidal height of their habitat. The gradient of amphibious lifestyle includes passive remainers that stay in the intertidal zone as tides ebb, active emergers that deliberately leave water in response to poor aquatic conditions and highly mobile amphibious skipper fishes that may spend more time out of water than in it. Normal terrestrial activity is usually aerobic and metabolic rates in air and water are similar. Anaerobic metabolism may be employed during forced exercise or when exposed to aquatic hypoxia. Adaptations for amphibious life include reductions in gill surface area, increased reliance on the skin for respiration and ion exchange, high affinity of haemoglobin for oxygen and adjustments to ventilation and metabolism while in air. Intertidal fishes remain close to water and do not travel far terrestrially, and are unlikely to migrate or colonize new habitats at present, although in the past this may have happened. Many fish species spawn in the intertidal zone, including some that do not breathe air, as eggs and embryos that develop in the intertidal zone benefit from tidal air emergence. With air breathing, amphibious intertidal fishes survive in a variable habitat with minimal adjustments to existing structures. Closely related species in different microhabitats provide unique opportunities for comparative studies.

  7. Tidal alignment of galaxies

    NASA Astrophysics Data System (ADS)

    Blazek, Jonathan; Vlah, Zvonimir; Seljak, Uroš

    2015-08-01

    We develop an analytic model for galaxy intrinsic alignments (IA) based on the theory of tidal alignment. We calculate all relevant nonlinear corrections at one-loop order, including effects from nonlinear density evolution, galaxy biasing, and source density weighting. Contributions from density weighting are found to be particularly important and lead to bias dependence of the IA amplitude, even on large scales. This effect may be responsible for much of the luminosity dependence in IA observations. The increase in IA amplitude for more highly biased galaxies reflects their locations in regions with large tidal fields. We also consider the impact of smoothing the tidal field on halo scales. We compare the performance of this consistent nonlinear model in describing the observed alignment of luminous red galaxies with the linear model as well as the frequently used "nonlinear alignment model," finding a significant improvement on small and intermediate scales. We also show that the cross-correlation between density and IA (the "GI" term) can be effectively separated into source alignment and source clustering, and we accurately model the observed alignment down to the one-halo regime using the tidal field from the fully nonlinear halo-matter cross correlation. Inside the one-halo regime, the average alignment of galaxies with density tracers no longer follows the tidal alignment prediction, likely reflecting nonlinear processes that must be considered when modeling IA on these scales. Finally, we discuss tidal alignment in the context of cosmic shear measurements.

  8. Comparison of impedance and inductance ventilation sensors on adults during breathing, motion, and simulated airway obstruction.

    PubMed

    Cohen, K P; Ladd, W M; Beams, D M; Sheers, W S; Radwin, R G; Tompkins, W J; Webster, J G

    1997-07-01

    The goal of this study was to compare the relative performance of two noninvasive ventilation sensing technologies on adults during artifacts. We recorded changes in transthoracic impedance and cross-sectional area of the abdomen (abd) and rib cage (rc) using impedance pneumography (IP) and respiratory inductance plethysmography (RIP) on ten adult subjects during natural breathing, motion artifact, simulated airway obstruction, yawning, snoring, apnea, and coughing. We used a pneumotachometer to measure air flow and tidal volume as the standard. We calibrated all sensors during natural breathing, and performed measurements during all maneuvers without changing the calibration parameters. No sensor provided the most-accurate measure of tidal volume for all maneuvers. Overall, the combination of inductance sensors [RIP(sum)] calibrated during an isovolume maneuver had a bias (weighted mean difference) as low or lower than all individual sensors and all combinations of sensors. The IP(rc) sensor had a bias as low or lower than any individual sensor. The cross-correlation coefficient between sensors was high during natural breathing, but decreased during artifacts. The cross correlation between sensor pairs was lower during artifacts without breathing than it was during maneuvers with breathing for four different sensor combinations. We tested a simple breath-detection algorithm on all sensors and found that RIP(sum) resulted in the fewest number of false breath detections, with sensitivity of 90.8% and positive predictivity of 93.6%.

  9. Breathing: Rhythmicity, Plasticity, Chemosensitivity

    PubMed Central

    Feldman, Jack L.; Mitchell, Gordon S.; Nattie, Eugene E.

    2010-01-01

    Breathing is a vital behavior that is particularly amenable to experimental investigation. We review recent progress on three problems of broad interest. (i) Where and how is respiratory rhythm generated? The preBötzinger Complex is a critical site, whereas pacemaker neurons may not be essential. The possibility that coupled oscillators are involved is considered. (ii) What are the mechanisms that underlie the plasticity necessary for adaptive changes in breathing? Serotonin-dependent long-term facilitation following intermittent hypoxia is an important example of such plasticity, and a model that can account for this adaptive behavior is discussed. (iii) Where and how are the regulated variables CO2 and pH sensed? These sensors are essential if breathing is to be appropriate for metabolism. Neurons with appropriate chemosensitivity are spread throughout the brainstem; their individual properties and collective role are just beginning to be understood. PMID:12598679

  10. The effect of inspiratory muscle fatigue on breathing pattern and ventilatory response to CO2.

    PubMed Central

    Mador, M J; Tobin, M J

    1992-01-01

    1. The effects of inducing inspiratory muscle fatigue on the subsequent breathing pattern were examined during resting unstimulated breathing and during CO2 rebreathing. In addition, we examined whether induction of inspiratory muscle fatigue alters CO2 responsiveness. 2. Global inspiratory muscle fatigue and diaphragmatic fatigue were achieved by having subjects breathe against an inspiratory resistive load while generating a predetermined fraction of either their maximal mouth pressure or maximal transdiaphragmatic pressure until they were unable to generate the target pressure. 3. Induction of inspiratory muscle fatigue had no effect on the subsequent breathing pattern during either unstimulated breathing or during CO2 rebreathing. 4. Following induction of inspiratory muscle fatigue, the slope of the ventilatory response to CO2 was significantly decreased from 18.8 +/- 3.3 during control to 13.8 +/- 2.1 l min-1 (% end-tidal CO2 concentration)-1 with fatigue (P < 0.02). PMID:1484352

  11. Limits to Tidal Power

    NASA Astrophysics Data System (ADS)

    Garrett, C.

    2008-12-01

    Ocean tides have been proposed as a source of renewable energy, though the maximum available power may be shown to be only a fraction of the present dissipation rate of 3.5 TW, which is small compared with global insolation (nearly 105 TW), wind dissipation (103 TW), and even human power usage of 15 TW. Nonetheless, tidal power could be a useful contributor in some locations. Traditional use of tidal power, involving the trapping of water behind a barrage at high tide, can produce an average power proportional to the area of the headpond and the square of the tidal range; the power density is approximately 6 W per square meter for a tidal range of 10 m. Capital costs and fears of environmental damage have put barrage schemes in disfavor, with interest turning to the exploitation of strong tidal currents, using turbines in a manner similar to wind turbines. There is a limit to the available power, however, as adding turbines reduces the flow, ultimately reducing the power. For sinusoidal forcing of flow in a channel connecting two large open basins, the maximum available power may be shown to be given approximately by 0.2ρ g a Q_max, where ρ is the water density, g gravity, a the amplitude of the tidal sea level difference along the channel, and Q_max is the maximum volume flux in the natural state. The same formula applies if the channel is the entrance to a semi-enclosed basin, with a now the amplitude of the external tide. A flow reduction of approximately 40% is typically associated with the maximum power extraction. The power would be reduced if only smaller environmental changes are acceptable, and reduced further by drag on supporting structures, dissipation in turbine wakes, and internal inefficiencies. It can be suggested that the best use of strong, cold, tidal currents is to provide cooling water for nuclear reactors.

  12. Use of a single pair of magnetometer coils to monitor breathing patterns in an intensive care unit

    PubMed Central

    Rees, P J; Higenbottam, T W; Clark, T J H

    1980-01-01

    The use of a single pair of magnetometer coils placed centrally on the trunk to record tidal volumes and breath times has been evaluated in five normal subjects in five positions. Breath times were accurate in all positions tested but tidal volumes were only reliable with the subjects lying and the backrest raised to 45° or in the supine position only for volumes up to 1000 ml. Using this system, recordings have been made in seven patients with barbiturate overdose, five with salicylate overdose, and five undergoing anaesthesia with thiopentone. The single pair of coils was satisfactory for measuring changes in the pattern of breathing in these patients. In barbiturate overdose in five patients there was initially an increase in respiratory frequency with a decrease in tidal volume. As these patients recovered the tidal volume increased and the respiratory rate slowed. In two patients who had a raised PaCO2 there was initially reduction of both tidal volume and respiratory rate, both increasing as the patients recovered. Monitoring respiratory rate appears to be a useful guide in barbiturate overdose; a slowing of the rate without recovery of consciousness warrants further investigation to assess the need for ventilatory support. The single pair of coils were also satisfactory for measuring the increased tidal volume in salicylate overdose. As after other respiratory stimuli in man, increased ventilation occurred predominantly through changes in tidal volume and expiratory time while inspiratory time changed very little. PMID:7434290

  13. AN APPROACH FOR CLASSIFYING TIDAL REGIMES BASED ON TIDAL CONSTITUENTS

    EPA Science Inventory

    Tidal fluctuations can be one of the dominant physical processes in estuaries. This paper presents a numerical classification of tidal regimes that can be used to summarize local conditions and facilitate comparisons among locations. Tide predictions are customarily calculated ...

  14. Life and Breath

    ERIC Educational Resources Information Center

    Ellis, Helen D.

    1974-01-01

    This article describes a public education program combining the screening process and a follow-up program for teaching victims of emphysema and other respiratory diseases how to better their living condition through proper breathing, avoidance of air pollutants and cigarette smoking, and taking better care of themselves physically. (PD)

  15. Metabolic breath analyzer

    NASA Technical Reports Server (NTRS)

    Perry, C. L.

    1971-01-01

    Instrument measures metabolic breathing rate and dynamics of human beings in atmospheres ranging from normal air to 100 percent oxygen at ambient pressures from 14.7 to 3.0 psia. Measurements are made at rest or performing tasks up to maximum physical capacity under either zero or normal gravity.

  16. Breathing Like a Fish

    ERIC Educational Resources Information Center

    Katsioloudis, Petros J.

    2010-01-01

    Being able to dive and breathe underwater has been a challenge for thousands of years. In 1980, Fuji Systems of Tokyo developed a series of prototype gills for divers as a way of demonstrating just how good its membranes are. Even though gill technology has not yet reached the point where recipients can efficiently use implants to dive underwater,…

  17. Breathing metabolic simulator

    NASA Technical Reports Server (NTRS)

    Bartlett, R. G., Jr.; Hendricks, C. M.; Morison, W. B.

    1972-01-01

    A description is given of an automatic computer controlled second generation breathing metabolic simulator (BMS). The simulator is used for evaluating and testing respiratory diagnostic, monitoring, support, and resuscitation equipment. Any desired sequence of metabolic activities can be simulated on the device for up to 15 hours. The computer monitors test procedures and provides printouts of test results.

  18. Tidal Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Duc, P.-A.; Mirabel, I. F.; Brinks, E.

    The life and evolution of galaxies are dramatically affected by environmental effects. Interactions with the intergalactic medium and collisions with companions cause major perturbations in the morphology and contents of galaxies: in particular stars and gas clouds may be gravitationally pulled out from their parent galaxies during tidal encounters, forming rings, tails and bridges. This debris of collisions lies at the origin of a new generation of small galaxies, the so-called "tidal dwarf galaxies" (TDGs). The authors have carried out multi-wavelength observations of some 20 TDGs. These systems are made of two stellar components: young stars, formed from the recent collapse of expelled H I clouds, and an older stellar population, tidally pulled out from the disks of their interacting parent galaxies. In the observed TDGs, the current star formation episode is fuelled by a large reservoir of H I gas and is younger than 10 Myr.

  19. Sigh-induced changes of breathing pattern in preterm infants

    PubMed Central

    Jost, Kerstin; Latzin, Philipp; Fouzas, Sotirios; Proietti, Elena; Delgado-Eckert, Edgar W; Frey, Urs; Schulzke, Sven M

    2015-01-01

    Sighs are thought to play an important role in control of breathing. It is unclear how sighs are triggered, and whether preterm birth and lung disease influence breathing pattern prior to and after a sigh in infants. To assess whether frequency, morphology, size, and short-term variability in tidal volume (VT) before, during, and after a sigh are influenced by gestational age at birth and lung disease (bronchopulmonary dysplasia, BPD) in former preterm infants and healthy term controls measured at equivalent postconceptional age (PCA). We performed tidal breathing measurements in 143 infants during quiet natural sleep at a mean (SD) PCA of 44.8 (1.3) weeks. A total of 233 sighs were analyzed using multilevel, multivariable regression. Sigh frequency in preterm infants increased with the degree of prematurity and severity of BPD, but was not different from that of term controls when normalized to respiratory rate. After a sigh, VT decreased remarkably in all infants (paired t-test: P < 0.001). There was no major effect of prematurity or BPD on various indices of sigh morphology and changes in VT prior to or after a sigh. Short-term variability in VT modestly increased with maturity at birth and infants with BPD showed an earlier return to baseline variability in VT following a sigh. In early infancy, sigh-induced changes in breathing pattern are moderately influenced by prematurity and BPD in preterm infants. The major determinants of sigh-related breathing pattern in these infants remain to be investigated, ideally using a longitudinal study design. PMID:26564066

  20. Tidally Heated Terrestrial Exoplanets

    NASA Astrophysics Data System (ADS)

    Henning, Wade Garrett

    This work models the surface and internal temperatures for hypothetical terrestrial planets in situations involving extreme tidal heating. The feasibility of such planets is evaluated in terms of the orbital perturbations that may give rise to them, their required proximity to a hoststar, and the potential for the input tidal heating to cause significant partial melting of the mantle. Trapping terrestrial planets into 2:1 resonances with migrating Hot Jupiters is considered as a reasonable way for Earth-like worlds to both maintain high eccentricities and to move to short enough orbital periods (1-20 days) for extreme tidal heating to occur. Secular resonance and secular orbital perturbations may support moderate tidal heating at a low equilibrium eccentricity. At orbital periods below 10-30 days, with eccentricities from 0.01 to 0.1, tidal heat may greatly exceed radiogenic heat production. It is unlikely to exceed insolation, except when orbiting very low luminosity hosts, and thus will have limited surface temperature expression. Observations of such bodies many not be able to detect tidal surface enhancements given a few percent uncertainty in albedo, except on the nightside of spin synchronous airless objects. Otherwise detection may occur via spectral detection of hotspots or high volcanic gas concentrations including sulfur dioxide and hydrogen sulfide. The most extreme cases may be able to produce magma oceans, or magma slush mantles with up to 40-60% melt fractions. Tides may alter the habitable zones for smaller red dwarf stars, but are generally detrimental. Multiple viscoelastic models, including the Maxwell, Voigt-Kelvin, Standard Anelastic Solid, and Burgers rheologies are explored and applied to objects such as Io and the super-Earth planet GJ 876d. The complex valued Love number for the Burgers rheology is derived and found to be a useful improvement when modeling the low temperature behavior of tidal bodies, particularly during low eccentricity

  1. Acute theophylline exposure modulates breathing activity through a cervical contusion.

    PubMed

    Hoy, Kevin C; Alilain, Warren J

    2015-09-01

    Cervical spinal contusion injuries are the most common form of spinal cord injury (>50%) observed in humans. These injuries can result in the impaired ability to breathe. In this study we examine the role of theophylline in the rescue of breathing behavior after a cervical spinal contusion. Previous research in the C2 hemisection model has shown that acute administration of theophylline can rescue phrenic nerve activity and diaphragmatic EMG on the side ipsilateral to injury. However, this effect is dependent on intact and uninjured pathways. In this study we utilized a cervical contusion injury model that more closely mimics the human condition. This injury model can determine the effectiveness of therapeutic interventions, in this case theophylline, on the isolated contused pathways of the spinal cord. Three weeks after a 150 kD C3/4 unilateral contusion subjects received a 15 mg/kg dose of theophylline prior to a contralateral C2 hemisection. Subjects that received theophylline were able to effectively utilize damaged pathways to breathe for up to 2 min, while subjects treated with saline were unable to support ventilation. Through these experiments, we demonstrate that theophylline can make injured pathways that mediate breathing more effective and therefore, suggest a potential therapeutic role in the critical time points immediately after injury.

  2. Breathing-Synchronized Delivery: A Potential Four-Dimensional Tomotherapy Treatment Technique

    SciTech Connect

    Zhang Tiezhi . E-mail: tiezhi.zhang@beaumont.edu; Lu Weiguo; Olivera, Gustavo H.; Keller, Harry; Jeraj, Robert; Manon, Rafael; Mehta, Minesh; Mackie, Thomas R.; Paliwal, Bhudatt

    2007-08-01

    Purpose: To introduce a four-dimensional (4D) tomotherapy treatment technique with improved motion control and patient tolerance. Methods and Materials: Computed tomographic images at 10 breathing phases were acquired for treatment planning. The full exhalation phase was chosen as the planning phase, and the CT images at this phase were used as treatment-planning images. Region of interest delineation was the same as in traditional treatment planning, except that no breathing motion margin was used in clinical target volume-planning target volume expansion. The correlation between delivery and breathing phases was set assuming a constant gantry speed and a fixed breathing period. Deformable image registration yielded the deformation fields at each phase relative to the planning phase. With the delivery/breathing phase correlation and voxel displacements at each breathing phase, a 4D tomotherapy plan was obtained by incorporating the motion into inverse treatment plan optimization. A combined laser/spirometer breathing tracking system has been developed to monitor patient breathing. This system is able to produce stable and reproducible breathing signals representing tidal volume. Results: We compared the 4D tomotherapy treatment planning method with conventional tomotherapy on a static target. The results showed that 4D tomotherapy can achieve dose distributions on a moving target similar to those obtained with conventional delivery on a stationary target. Regular breathing motion is fully compensated by motion-incorporated breathing-synchronized delivery planning. Four-dimensional tomotherapy also has close to 100% duty cycle and does not prolong treatment time. Conclusion: Breathing-synchronized delivery is a feasible 4D tomotherapy treatment technique with improved motion control and patient tolerance.

  3. Human breathing and eye blink rate responses to airborne chemicals.

    PubMed Central

    Walker, J C; Kendal-Reed, M; Utell, M J; Cain, W S

    2001-01-01

    Increased levels of air pollution have been linked with morbidity and mortality, but mechanisms linking physiologic responses to quality of life and productivity issues remain largely unknown. Individuals often report irritation of the nose and/or eyes upon exposures to environmental contaminants. Evaluation of these self-reports would be greatly aided by the development of valid physiological markers. Chamber studies (unencumbered exposures) of nonsmoker responses to environmental tobacco smoke offer two candidate end points: (a) Tidal volume increases and breathing frequency declines with stimuli that elicit only moderate irritation. (b) Eye blink rate increases only with a concentration sufficiently high to cause progressive worsening of eye irritation with prolonged exposure. Experiments with very brief nasal-only presentations also suggest the value of breathing changes as sensitive markers of irritation: (a) Tidal volume is inversely related to perceived nasal irritation (NI) intensity in both normal and anosmic (lacking olfactory input) individuals, although normals exhibit greater NI sensitivity. (b) Inhalation duration, in both groups, declines only with trigeminal activation sufficient to cause readily perceptible NI in anosmics. Changes in eye blink rate and breathing may be useful in the investigation of irritation and other effects of air pollution, and could be quite useful in investigations of mixtures of volatile organic compounds. PMID:11544155

  4. Tidal power plants in Russia

    SciTech Connect

    Bernshtein, L.B. )

    1994-01-01

    This article examines the performance of tidal power plants in Russia and the expansion of tidal plant to new sites. The topics of the article include remote construction and transport techniques, pilot plant performance, economics and payback, and a review of global tidal power plant designs that are on hold due to economic problems relating to the global economy.

  5. Slow breathing training reduces resting blood pressure and the pressure responses to exercise.

    PubMed

    Jones, C U; Sangthong, B; Pachirat, O; Jones, D A

    2015-01-01

    Slow breathing training reduces resting blood pressure, probably by modifying central autonomic control, but evidence for this is lacking. The pressor response to static handgrip exercise is a measure of autonomic control and the aim of this study was to determine whether slow breathing training modulates the pressor responses to exercise of untrained muscles. Twenty hypertensive patients trained for 8 weeks, 10 with unloaded slow breathing (Unloaded) and 10 breathing against an inspiratory load of 20 cm H(2)O (Loaded). Ten subjects were untrained controls. Subjects performed a 2 min handgrip pressor test (30 % MVC) pre- and post-training, and blood pressure and heart rate (HR) were measured before the contraction, at the end and following 2 min recovery. Resting systolic (sBP) and HR were reduced as a result of training, as reported previously. After training there was both a smaller pressor response to hand grip exercise and a more rapid recovery of sBP and HR compared to pre-training. There were no changes in the Controls and no differences between the Unloaded and Loaded groups. Combining the two training groups, the sBP response to handgrip exercise after training was reduced by 10 mm Hg (95 % CI: -7, -13) and HR by 5 bpm (95 % CI: -4, -6), all p<0.05. These results are consistent with slow breathing training modifying central mechanisms regulating cardiovascular function. PMID:25804100

  6. Ionospheric response to tidal waves measured by dynasonde techniques

    NASA Astrophysics Data System (ADS)

    Negrea, Cǎtǎlin; Zabotin, Nikolay; Bullett, Terence; Codrescu, Mihail; Fuller-Rowell, Tim

    2016-01-01

    Atmospheric tides are known to have a dramatic influence on thermospheric and ionospheric structure and variability. Considerable effort goes into understanding characteristics of tidal modes, their interactions with planetary and gravity waves and other tidal modes, as well as their influence on the background state of the thermosphere-ionosphere system. For the altitude interval between roughly 120 and 400 km, this effort is somewhat hindered by the lack of global observations. We propose a new method of determining tidal variability by making use of dynasonde measurements. The NeXtYZ inversion procedure produces altitude profiles of the ionospheric parameters with a vertical resolution typically better than 1 km. This, together with the typical 2 min cadence of the instrument, results in extensive data sets with wide temporal and altitude coverage. At any given altitude we have nonuniform sampling due to the natural ionospheric variability. A Lomb-Scargle implementation is used to obtain equivalent results at all altitudes and locations. We report height profiles of the first three tidal harmonics derived from dynasonde measurements. The data analyzed include the vertical electron density profiles, the ionospheric X (east-west) "tilt" measurement, and the derived zonal plasma density gradient. Both the tilt and the gradient are shown to be sensitive tracers of atmospheric waves. We use data from Wallops Island and San Juan, for two time intervals: 6 May- 6 June and 9 October- 8 November 2013, thus capturing seasonal, latitudinal, and altitude variations of tidal amplitude and phase. This proves the potential of using dynasonde-capable instruments as a data source for tidal studies in the thermosphere.

  7. Emergency Response Breathing Apparatus

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Aerospace Design & Development, Inc.'s (ADD's) SCAMP was developed under an SBIR contract through Kennedy Space Center. SCAMP stands for Supercritical Air Mobility Pack. The technology came from the life support fuel cell support systems used for the Apollo and Space Shuttle programs. It uses supercritical cryogenic air and is able to function in microgravity environments. SCAMP's self-contained breathing apparatus(SCBA) systems are also ground-based and can provide twice as much air than traditional SCBA's due to its high-density capacity. The SCAMP system was designed for use in launch pad emergency rescues. ADD also developed a protective suit for use with SCAMP that is smaller and lighter system than the old ones. ADD's SCAMP allows for body cooling and breathing from the supercritical cryogenic air, requiring no extra systems. The improvement over the traditional SCBA allows for a reduction of injuries, such as heat stress, and makes it easier for rescuers to save lives.

  8. [TMJ, eating and breathing].

    PubMed

    Cheynet, F

    2016-09-01

    The study of the relationship between temporomandibular joints (TMJ), mastication and ventilation and the involvement of these two functions in the genesis of primary Temporomandibular Disorders (TMD) and in some dentofacial deformities, was initiated in France, more than 30years, by Professor Raymond Gola. Once criticized the weakness of the scientific literature in this domain, the originality of the TMJ within the masticatory system is recalled with its huge adaptation potential to very different biomechanical constraints according to the age and masticatory activities during the day. But the biomechanics of the masticatory system does not stop at night and the positions of the mandible and head during sleep should be studied carefully. In case of nocturnal mouth breathing with open mouth, the predominant sleeping position (generating small but long-term strengths) may be deleterious to the condyle-disc complex, to the surrounding muscles and the occlusal relationships. Some condyle-disc displacements and asymmetric malocclusions occur in this long portion of life what sleep, especially as oral breathing leads to a lot of dysfunctions (low position of the tongue, labio-lingual dysfunctions, exacerbation of bruxism sleep…). The aim of this work was to share our multidisciplinary experience of the biomechanical consequences of the nocturnal mouth breathing on the face involving orthodontists, maxillofacial surgeons, ENT, allergists, speech therapists, physiotherapists and radiologists.

  9. [TMJ, eating and breathing].

    PubMed

    Cheynet, F

    2016-09-01

    The study of the relationship between temporomandibular joints (TMJ), mastication and ventilation and the involvement of these two functions in the genesis of primary Temporomandibular Disorders (TMD) and in some dentofacial deformities, was initiated in France, more than 30years, by Professor Raymond Gola. Once criticized the weakness of the scientific literature in this domain, the originality of the TMJ within the masticatory system is recalled with its huge adaptation potential to very different biomechanical constraints according to the age and masticatory activities during the day. But the biomechanics of the masticatory system does not stop at night and the positions of the mandible and head during sleep should be studied carefully. In case of nocturnal mouth breathing with open mouth, the predominant sleeping position (generating small but long-term strengths) may be deleterious to the condyle-disc complex, to the surrounding muscles and the occlusal relationships. Some condyle-disc displacements and asymmetric malocclusions occur in this long portion of life what sleep, especially as oral breathing leads to a lot of dysfunctions (low position of the tongue, labio-lingual dysfunctions, exacerbation of bruxism sleep…). The aim of this work was to share our multidisciplinary experience of the biomechanical consequences of the nocturnal mouth breathing on the face involving orthodontists, maxillofacial surgeons, ENT, allergists, speech therapists, physiotherapists and radiologists. PMID:27554491

  10. Cardiovascular Biomarkers In Exhaled Breath

    PubMed Central

    Cikach, Frank S.; Dweik, Raed A.

    2014-01-01

    With each breath we exhale, thousands of molecules are expelled in our breath giving individuals a “breath-print” that can tell a lot about them and their state of health. Breath analysis is rapidly evolving as the new frontier in medical testing. The end of the 20th century and the beginning of the 21st century have arguably witnessed a revolution in our understanding of the constituents of exhaled breath and the development of the field of breath analysis and testing. Thanks to major breakthroughs in new technologies (infrared, electrochemical, chemiluminescence, and others) and the availability of mass spectrometers, the field of breath analysis has made considerable advances in the 21st century. Several methods are now in clinical use or nearly ready to enter that arena. Breath analysis has the potential to offer relatively inexpensive, rapid, noninvasive methods for detecting and/or monitoring a variety of diseases. Breath analysis also has applications in fields beyond medicine, including environmental monitoring, security and others. This review will focus on exhaled breath as a potential source of biomarkers for medical applications with specific attention to applications (and potential applications) in cardiovascular disease. PMID:22824108

  11. Breathing and affective picture processing across the adult lifespan.

    PubMed

    Gomez, Patrick; Filippou, Dimitra; Pais, Bruno; von Gunten, Armin; Danuser, Brigitta

    2016-09-01

    The present study investigated differences between healthy younger, middle-aged, and older adults in their respiratory responses to pictures of different valence and arousal. Expiratory time shortened and end-tidal PCO2 decreased with increasing arousal in all age groups; yet, compared to younger adults, older adults' overall change from baseline was smaller for expiratory time and larger for end-tidal PCO2. Contrary to their younger counterparts, older adults' inspiratory time did not shorten with increasing arousal. Inspiratory duty cycle did not covary with affective ratings for younger adults, increased with unpleasantness for middle-aged adults, and increased with arousal for older adults. Thoracic breathing increased with increasing unpleasantness only among older adults. Age had no effects on mean inspiratory flow and minute ventilation, which both augmented as arousal increased. We discuss how age effects on respiratory response magnitude and pattern may depend on age-associated biological changes or reflect age-related differences in emotional processing.

  12. Tidal disruption events

    NASA Astrophysics Data System (ADS)

    Levan, A.

    2014-07-01

    Tidal disruption events (TDEs) provide a powerful probe of many astrophysical processes. They occur when the powerful tidal field around a black hole disrupts a passing star which is subsequently accreted. The resulting signal is a powerful X-ray, UV/opt and possibly even radio source, that provides us with a view of accretion aroud supermassive black holes from switch-on to switch-off over the timescale of years. TDEs probe accretion physics, the ubquity of black holes in galactic nuclei and dynamics in their cores, offering a novel route to addressing these issues. I will review observations of TDEs over the past decade, outlining how samples of candidates have been gradually building, and how they can be identified against other more common transient events. I will also discuss the implications of the discovery of a population of TDEs apparently launching relativisitc jets, and how these powerful transients may be detected in upcoming X-ray to radio surveys.

  13. Developments in tidal power

    NASA Astrophysics Data System (ADS)

    Charlier, R. H.

    Successful, planned, and potential tidal power plants and sites are discussed. Units are in operation in France and Russia, with the French plant using reversible blade turbines being used as a design guide for plants in Argentina and Australia. The U.S. is studying the feasibility of a plant in Passamaquaddy Bay, and Canada is pursuing construction of a plant in the Bay of Fundy. The Severn River in Great Britain is receiving a site study, and over a hundred plants have been built as local power systems in China. Bulb-type turbines, which enhance the volume emptying and filling the retaining basin, are considered as the highest performing power unit. Simpler one-way flow turbines have been suggested as more economical to install. Governmental, institutional, and investor impediments to tidal power plant are explored.

  14. Developments in tidal power

    SciTech Connect

    Charlier, R.H.

    1982-08-01

    Marine power has been the subject of numerous conferences and an impressive number of studies has considered schemes to harness ocean energy. Recently some attention has also been given to small marine power projects. Thermal difference, tides and waves appear to offer the greatest immediate promise, but so far only tidal power has been tapped on a large scale. Since completion of the Rance plant new concepts have been developed and new schemes designed. Some aspects are briefly examined here.

  15. Ammonia in breath and emitted from skin.

    PubMed

    Schmidt, F M; Vaittinen, O; Metsälä, M; Lehto, M; Forsblom, C; Groop, P-H; Halonen, L

    2013-03-01

    Ammonia concentrations in exhaled breath (eNH3) and skin gas of 20 healthy subjects were measured on-line with a commercial cavity ring-down spectrometer and compared to saliva pH and plasma ammonium ion (NH(+)4), urea and creatinine concentrations. Special attention was given to mouth, nose and skin sampling procedures and the accurate quantification of ammonia in humid gas samples. The obtained median concentrations were 688 parts per billion by volume (ppbv) for mouth-eNH3, 34 ppbv for nose-eNH3, and 21 ppbv for both mouth- and nose-eNH3 after an acidic mouth wash (MW). The median ammonia emission rate from the lower forearm was 0.3 ng cm(-2) min(-1). Statistically significant (p < 0.05) correlations between the breath, skin and plasma ammonia/ammonium concentrations were not found. However, mouth-eNH3 strongly (p < 0.001) correlated with saliva pH. This dependence was also observed in detailed measurements of the diurnal variation and the response of eNH3 to the acidic MW. It is concluded that eNH3 as such does not reflect plasma but saliva and airway mucus NH(+)4 concentrations and is affected by saliva and airway mucus pH. After normalization with saliva pH using the Henderson-Hasselbalch equation, mouth-eNH3 correlated with plasma NH(+)4, which points to saliva and plasma NH(+)4 being linked via hydrolysis of salivary urea.

  16. Effect of transcendental meditation on breathing and respiratory control.

    PubMed

    Wolkove, N; Kreisman, H; Darragh, D; Cohen, C; Frank, H

    1984-03-01

    We studied the effect of transcendental meditation (TM) on breathing using 16 experienced meditators and 16 control subjects. In controls, there was no significant difference in minute ventilation (VE), respiratory pattern, or hypercapnic response, whether breathing with eyes open-awake (CA), or with eyes closed-relaxing (CR). In meditators, VE decreased significantly during quiet breathing from 14.0 +/- 0.7 1/min with eyes open-awake (MA) to 12.4 +/- 0.6 1/min during meditation (MM) (P less than 0.02). The change in VE during meditation was due to a decrease in tidal volume (VT) resulting from a shortened inspiratory time (TI). Meditation was associated with a decreased response to progressive hypercapnia from 3.7 +/- 0.4 to 2.5 +/- 0.21 X min-1 X Torr-1 during MA and MM trials, respectively (P less than 0.01). During meditation VT was smaller at a given alveolar PCO2 than during MA studies because of a decrease in mean inspiratory flow rate (VT/TI). These observations suggest that an alteration in wakefulness, more subtle than sleep or the unconscious state, can significantly affect the chemical and neural regulation of breathing.

  17. Relativistic tidal disruption events

    NASA Astrophysics Data System (ADS)

    Levan, A.

    2012-12-01

    In March 2011 Swift detected an extremely luminous and long-lived outburst from the nucleus of an otherwise quiescent, low luminosity (LMC-like) galaxy. Named Swift J1644+57, its combination of high-energy luminosity (1048 ergs s-1 at peak), rapid X-ray variability (factors of >100 on timescales of 100 seconds) and luminous, rising radio emission suggested that we were witnessing the birth of a moderately relativistic jet (Γ ˜ 2 - 5), created when a star is tidally disrupted by the supermassive black hole in the centre of the galaxy. A second event, Swift J2058+0516, detected two months later, with broadly similar properties lends further weight to this interpretation. Taken together this suggests that a fraction of tidal disruption events do indeed create relativistic outflows, demonstrates their detectability, and also implies that low mass galaxies can host massive black holes. Here, I briefly outline the observational properties of these relativistic tidal flares observed last year, and their evolution over the first year since their discovery.

  18. Probing plasmonic breathing modes optically

    SciTech Connect

    Krug, Markus K. Reisecker, Michael; Hohenau, Andreas; Ditlbacher, Harald; Trügler, Andreas; Hohenester, Ulrich; Krenn, Joachim R.

    2014-10-27

    The confinement of surface plasmon modes in flat nanoparticles gives rise to plasmonic breathing modes. With a vanishing net dipole moment, breathing modes do not radiate, i.e., they are optically dark. Having thus escaped optical detection, breathing modes were only recently revealed in silver nanodisks with electron energy loss spectroscopy in an electron microscope. We show that for disk diameters >200 nm, retardation induced by oblique optical illumination relaxes the optically dark character. This makes breathing modes and thus the full plasmonic mode spectrum accessible to optical spectroscopy. The experimental spectroscopy data are in excellent agreement with numerical simulations.

  19. Respiratory muscle activity during sleep-induced periodic breathing in the elderly.

    PubMed

    Hudgel, D W; Hamilton, H B

    1994-11-01

    During spontaneous sleep-induced periodic breathing in elderly subjects, we have found that tidal volume oscillations are related to reciprocal oscillations in upper airway resistance. The purpose of this study was to address the mechanism of the relationship between oscillations in tidal volume and upper airway resistance in elderly subjects with sleep-induced periodic breathing. We hypothesized that the spontaneous periodic breathing observed in non-rapid-eye-movement (NREM) sleep in elderly subjects would be closely related to fluctuations in upper airway resistance and not to changes in central motor drive to ventilatory pump muscles. Therefore, in eight healthy elderly subjects, we measured costal margin chest wall peak moving time average electrical inspiratory activity (CW EMG), ventilation variables, and upper airway resistance during sleep. Five of eight subjects had significant sine wave oscillations in upper airway resistance and tidal volume. For these five subjects, there was a reciprocal exponential relationship between peak upper airway inspiratory resistance and tidal volume or minute ventilation [r = -0.60 +/- 0.20 (SD) (P < 0.05) and -0.55 +/- 0.26 (P < 0.05), respectively], such that as resistance increased, ventilation decreased. The relationship between CW EMG and tidal volume or minute ventilation was quite low (r = 0.12 +/- 0.32 and -0.07 +/- 0.27, respectively). This study demonstrated that oscillations in ventilation during NREM sleep in elderly subjects were significantly related to fluctuations in upper airway resistance but were not related to changes in chest wall muscle electrical activity. Therefore, changes in upper airway caliber likely contribute to oscillations in ventilation seen during sleep-induced periodic breathing in the elderly.

  20. Tidal Venuses: triggering a climate catastrophe via tidal heating.

    PubMed

    Barnes, Rory; Mullins, Kristina; Goldblatt, Colin; Meadows, Victoria S; Kasting, James F; Heller, René

    2013-03-01

    Traditionally, stellar radiation has been the only heat source considered capable of determining global climate on long timescales. Here, we show that terrestrial exoplanets orbiting low-mass stars may be tidally heated at high-enough levels to induce a runaway greenhouse for a long-enough duration for all the hydrogen to escape. Without hydrogen, the planet no longer has water and cannot support life. We call these planets "Tidal Venuses" and the phenomenon a "tidal greenhouse." Tidal effects also circularize the orbit, which decreases tidal heating. Hence, some planets may form with large eccentricity, with its accompanying large tidal heating, and lose their water, but eventually settle into nearly circular orbits (i.e., with negligible tidal heating) in the habitable zone (HZ). However, these planets are not habitable, as past tidal heating desiccated them, and hence should not be ranked highly for detailed follow-up observations aimed at detecting biosignatures. We simulated the evolution of hypothetical planetary systems in a quasi-continuous parameter distribution and found that we could constrain the history of the system by statistical arguments. Planets orbiting stars with masses<0.3 MSun may be in danger of desiccation via tidal heating. We have applied these concepts to Gl 667C c, a ∼4.5 MEarth planet orbiting a 0.3 MSun star at 0.12 AU. We found that it probably did not lose its water via tidal heating, as orbital stability is unlikely for the high eccentricities required for the tidal greenhouse. As the inner edge of the HZ is defined by the onset of a runaway or moist greenhouse powered by radiation, our results represent a fundamental revision to the HZ for noncircular orbits. In the appendices we review (a) the moist and runaway greenhouses, (b) hydrogen escape, (c) stellar mass-radius and mass-luminosity relations, (d) terrestrial planet mass-radius relations, and (e) linear tidal theories.

  1. Overland Tidal Power Generation Using Modular Tidal Prism

    SciTech Connect

    Khangaonkar, Tarang; Yang, Zhaoqing; Geerlofs, Simon H.; Copping, Andrea

    2010-03-01

    Naturally occurring sites with sufficient kinetic energy suitable for tidal power generation with sustained currents > 1 to 2 m/s are relatively rare. Yet sites with greater than 3 to 4 m of tidal range are relatively common around the U.S. coastline. Tidal potential does exist along the shoreline but is mostly distributed, and requires an approach which allows trapping and collection to also be conducted in a distributed manner. In this paper we examine the feasibility of generating sustainable tidal power using multiple nearshore tidal energy collection units and present the Modular Tidal Prism (MTP) basin concept. The proposed approach utilizes available tidal potential by conversion into tidal kinetic energy through cyclic expansion and drainage from shallow modular manufactured overland tidal prisms. A preliminary design and configuration of the modular tidal prism basin including inlet channel configuration and basin dimensions was developed. The unique design was shown to sustain momentum in the penstocks during flooding as well as ebbing tidal cycles. The unstructured-grid finite volume coastal ocean model (FVCOM) was used to subject the proposed design to a number of sensitivity tests and to optimize the size, shape and configuration of MTP basin for peak power generation capacity. The results show that an artificial modular basin with a reasonable footprint (≈ 300 acres) has the potential to generate 10 to 20 kw average energy through the operation of a small turbine located near the basin outlet. The potential of generating a total of 500 kw to 1 MW of power through a 20 to 40 MTP basin tidal power farms distributed along the coastline of Puget Sound, Washington, is explored.

  2. Tidal Venuses: triggering a climate catastrophe via tidal heating.

    PubMed

    Barnes, Rory; Mullins, Kristina; Goldblatt, Colin; Meadows, Victoria S; Kasting, James F; Heller, René

    2013-03-01

    Traditionally, stellar radiation has been the only heat source considered capable of determining global climate on long timescales. Here, we show that terrestrial exoplanets orbiting low-mass stars may be tidally heated at high-enough levels to induce a runaway greenhouse for a long-enough duration for all the hydrogen to escape. Without hydrogen, the planet no longer has water and cannot support life. We call these planets "Tidal Venuses" and the phenomenon a "tidal greenhouse." Tidal effects also circularize the orbit, which decreases tidal heating. Hence, some planets may form with large eccentricity, with its accompanying large tidal heating, and lose their water, but eventually settle into nearly circular orbits (i.e., with negligible tidal heating) in the habitable zone (HZ). However, these planets are not habitable, as past tidal heating desiccated them, and hence should not be ranked highly for detailed follow-up observations aimed at detecting biosignatures. We simulated the evolution of hypothetical planetary systems in a quasi-continuous parameter distribution and found that we could constrain the history of the system by statistical arguments. Planets orbiting stars with masses<0.3 MSun may be in danger of desiccation via tidal heating. We have applied these concepts to Gl 667C c, a ∼4.5 MEarth planet orbiting a 0.3 MSun star at 0.12 AU. We found that it probably did not lose its water via tidal heating, as orbital stability is unlikely for the high eccentricities required for the tidal greenhouse. As the inner edge of the HZ is defined by the onset of a runaway or moist greenhouse powered by radiation, our results represent a fundamental revision to the HZ for noncircular orbits. In the appendices we review (a) the moist and runaway greenhouses, (b) hydrogen escape, (c) stellar mass-radius and mass-luminosity relations, (d) terrestrial planet mass-radius relations, and (e) linear tidal theories. PMID:23537135

  3. Ventilatory inhomogeneity determined from multiple-breath washouts during sustained microgravity on Spacelab SLS-1

    NASA Technical Reports Server (NTRS)

    Prisk, G. Kim; Guy, Harold J. B.; Elliott, Ann R.; Paiva, Manuel; West, John B.

    1995-01-01

    We used multiple-breath N2 washouts (MBNW) to study the homogeneity of ventilation in four normal humans (mean age 42.5 yr) before, during, and after 9 days of exposure to microgravity on Spacelab Life Sciences-1. Subjects performed 20-breath MBNW at tidal volumes of approximately 700 ml and 12-breath MBNW at tidal volumes of approximately 1,250 ml. Six indexes of ventilatory inhomogeneity were derived from data from (1) distribution of specific ventilation (SV) from mixed-expired and (2) end-tidal N2, (3) change of slope of N2 washout (semilog plot) with time, (4) change of slope of normalized phase III of successive breaths, (5) anatomic lead dead space, and (6) Bohr dead space. Significant ventilatory inhomogeneity was seen in the standing position at normal gravity (1 G). When we compared standing 1 G with microgravity, the distributions of SV became slightly narrower, but the difference was not significant. Also, there were no significant changes in the change of slope of the N2 washout, change of normalized phase III slopes, or the anatomic and Bohr dead spaces. By contrast, transition from the standing to supine position in 1 G resulted in significantly broader distributions of SV and significantly greater changes in the changes in slope of the N2 washouts, indicating more ventilatory inhomogeneity in that posture. Thus these techniques can detect relatively small changes in ventilatory inhomogeneity. We conclude that the primary determinants of ventilatory inhomogeneity during tidal breathing in the upright posture are not gravitational in origin.

  4. Recognition of synodic and tropical tidal periodicities in tidal rhythmites

    SciTech Connect

    Archer, A.W. ); Kvale, E.P. ); Johnson, H.P. )

    1990-05-01

    Tidal processes are capable of producing bedding that records individual tidal events; however, only within the last decade have tidal cycles, such as neap-spring periodicities become widely recognized. Such cycles have been documented within thinly laminated, vertically accreted siltstones. The laminae exhibit systematic patterns of thickening and thinning that have been equated to the lunar orbital period (synodic month). However, modem tides are subject to periodicities other than the synodic month and such additional periods can be the causative mechanism for neap-spring tidal periods. Gravitational interactions of the earth, moon, and sun generate tides that fluctuate with periods that correspond to the phases of the moon (synodic month), declination of the moon (tropical month), and distance of the moon from the earth (anomalistic month). Although harmonic analyses of semidiurnal tidal data indicate that such systems are controlled by synodic factors, there are also indications that diurnal systems can be controlled by tropical factors. Thus neap-spring periods are not only related to lunar phase (synodic month), but can be related to tropical month (lunar declination) in diurnal systems. Analysis of laminae-thickness periodicities in a variety of Pennsylvanian tidal rhythmites, which include apparent examples of diurnal as well as semidiurnal tidal patterns, indicates similarities to modern tidal systems. For example, semidiurnal tidal rhythmites exhibit not only synodic periodicities but also exhibit a weaker, tropical periodicity. Conversely, within rhythmites that exhibit a diurnal pattern, it is not completely clear whether tropical or synodic periodicities are being expressed.

  5. Dissipation of Tidal Energy

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The moon's gravity imparts tremendous energy to the Earth, raising tides throughout the global oceans. What happens to all this energy? This question has been pondered by scientists for over 200 years, and has consequences ranging from the history of the moon to the mixing of the oceans. Richard Ray at NASA's Goddard Space Flight Center, Greenbelt, Md. and Gary Egbert of the College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Ore. studied six years of altimeter data from the TOPEX/Poseidon satellite to address this question. According to their report in the June 15 issue of Nature, about 1 terawatt, or 25 to 30 percent of the total tidal energy dissipation, occurs in the deep ocean. The remainder occurs in shallow seas, such as on the Patagonian Shelf. 'By measuring sea level with the TOPEX/Poseidon satellite altimeter, our knowledge of the tides in the global ocean has been remarkably improved,' said Richard Ray, a geophysicist at Goddard. The accuracies are now so high that this data can be used to map empirically the tidal energy dissipation. (Red areas, above) The deep-water tidal dissipation occurs generally near rugged bottom topography (seamounts and mid-ocean ridges). 'The observed pattern of deep-ocean dissipation is consistent with topographic scattering of tidal energy into internal motions within the water column, resulting in localized turbulence and mixing', said Gary Egbert an associate professor at OSU. One important implication of this finding concerns the possible energy sources needed to maintain the ocean's large-scale 'conveyor-belt' circulation and to mix upper ocean heat into the abyssal depths. It is thought that 2 terawatts are required for this process. The winds supply about 1 terawatt, and there has been speculation that the tides, by pumping energy into vertical water motions, supply the remainder. However, all current general circulation models of the oceans ignore the tides. 'It is possible that properly

  6. End-tidal CO2 in some aquatic mammals of large size.

    PubMed

    Mortola, Jacopo P; Seguin, Julie

    2009-01-01

    While resting on land or at the water surface, the breathing frequency (f) of aquatic mammals of medium and large size is lower than in terrestrial mammals of similar body weight (W), the difference widening with the increase in W. The allometric function for aquatic mammals is f proportional to W(-0.42) (f, breaths/min, W, kg) and that of terrestrial species is f proportional to W(-0.25). We asked whether or not resting breathing at such low f would entail high values of alveolar CO2. End-tidal alveolar CO2 pressure, taken as representative of alveolar CO2 pressure, PaCO2, was measured from the expired gas during resting breathing in captive specimens of aquatic species trained to rest in proximity of their keepers, either on land (walrus and sea lion) or at the water surface (dolphin, orca, beluga and hippopotamus). Their f during the recordings ranged from less than 1 (orca) to 6 (walrus) breaths/min. The average PaCO2 values ranged from 32 to 42 mm Hg, the peaks being a few mm Hg higher. These values were similar or slightly higher than literature data of many terrestrial species, with no relation to the animal f or W. The quasi-normality of PaCO2 in large aquatic species breathing at rest, despite their exceptionally low f and normal metabolism, can be explained mainly by two factors, their large tidal volume/W, about three times the average terrestrial value, and their peculiar breathing pattern with sustained high lung volume during the expiratory pause. This latter is key in avoiding a substantial rise in PaCO2 during the inter-breath pause. PMID:19026528

  7. SU-E-J-178: A Normalization Method Can Remove Discrepancy in Ventilation Function Due to Different Breathing Patterns

    SciTech Connect

    Qu, H; Yu, N; Stephans, K; Xia, P

    2014-06-01

    Purpose: To develop a normalization method to remove discrepancy in ventilation function due to different breathing patterns. Methods: Twenty five early stage non-small cell lung cancer patients were included in this study. For each patient, a ten phase 4D-CT and the voluntarily maximum inhale and exhale CTs were acquired clinically and retrospectively used for this study. For each patient, two ventilation maps were calculated from voxel-to-voxel CT density variations from two phases of the quiet breathing and two phases of the extreme breathing. For the quiet breathing, 0% (inhale) and 50% (exhale) phases from 4D-CT were used. An in-house tool was developed to calculate and display the ventilation maps. To enable normalization, the whole lung of each patient was evenly divided into three parts in the longitude direction at a coronal image with a maximum lung cross section. The ratio of cumulated ventilation from the top one-third region to the middle one-third region of the lung was calculated for each breathing pattern. Pearson's correlation coefficient was calculated on the ratios of the two breathing patterns for the group. Results: For each patient, the ventilation map from the quiet breathing was different from that of the extreme breathing. When the cumulative ventilation was normalized to the middle one-third of the lung region for each patient, the normalized ventilation functions from the two breathing patterns were consistent. For this group of patients, the correlation coefficient of the normalized ventilations for the two breathing patterns was 0.76 (p < 0.01), indicating a strong correlation in the ventilation function measured from the two breathing patterns. Conclusion: For each patient, the ventilation map is dependent of the breathing pattern. Using a regional normalization method, the discrepancy in ventilation function induced by the different breathing patterns thus different tidal volumes can be removed.

  8. Use of a turbine in a breath-by-breath computer-based respiratory measurement system.

    PubMed

    Venkateswaran, R S; Gallagher, R R

    1997-01-01

    The Computer-Based Respiratory Measurement System (CBRMS) is capable of analyzing individual breaths to monitor the kinetics of oxygen uptake, carbon dioxide production, tidal volumes, pulmonary ventilation, and other respiratory parameters during rest, exercise, and recovery. Respiratory gas volumes are measured by a calibrated turbine transducer while the respiratory gas concentrations are measured by a calibrated, fast-responding medical gas analyzer. To improve accuracy of the results, the inspiratory volumes and gas concentrations are measured and not assumed to be equal to expiratory volumes or ambient concentrations respectively. The respiratory gas volumes and concentration signals are digitized and stored in arrays. The gas volumes are converted to flow signals by software differentiation. These digitized data arrays are stored as files in a personal computer. Time alignment of the flow and gas concentration signals is performed at each breath for maximum accuracy in analysis. For system verification, data were obtained under resting conditions and under constant load exercises at 50 W, 100 W, and 150 W. These workloads were performed by a healthy, male subject on a bicycle ergometer. A strong correlation existed between the CBRMS steady-state results and the standard end-expirate bag collection technique. Thus, there is reason to believe that the CBRMS is capable of calculating respiratory transient responses accurately, a significant contribution to an understanding of total respiratory system function.

  9. Association between the rapid shallow breathing index and extubation success in patients with traumatic brain injury

    PubMed Central

    dos Reis, Helena França Correia; Almeida, Mônica Lajana Oliveira; da Silva, Mário Ferreira; Moreira, Julião Oliveira; Rocha, Mário de Seixas

    2013-01-01

    Objective To investigate the association between the rapid shallow breathing index and successful extubation in patients with traumatic brain injury. Methods This study was a prospective study conducted in patients with traumatic brain injury of both genders who underwent mechanical ventilation for at least two days and who passed a spontaneous breathing trial. The minute volume and respiratory rate were measured using a ventilometer, and the data were used to calculate the rapid shallow breathing index (respiratory rate/tidal volume). The dependent variable was the extubation outcome: reintubation after up to 48 hours (extubation failure) or not (extubation success). The independent variable was the rapid shallow breathing index measured after a successful spontaneous breathing trial. Results The sample comprised 119 individuals, including 111 (93.3%) males. The average age of the sample was 35.0±12.9 years old. The average duration of mechanical ventilation was 8.1±3.6 days. A total of 104 (87.4%) participants achieved successful extubation. No association was found between the rapid shallow breathing index and extubation success. Conclusion The rapid shallow breathing index was not associated with successful extubation in patients with traumatic brain injury. PMID:24213084

  10. Patient's breath controls comfort devices

    NASA Technical Reports Server (NTRS)

    Schrader, M.; Carpenter, B.; Nichols, C. D.

    1972-01-01

    Patient assist system for totally disabled persons was developed which permits a person, so paralyzed as to be unable to move, to activate by breathing, a call system to summon assistance, turn the page of a book, ajust his bed, or do any one of a number of other things. System consists of patient assist control and breath actuated switch.

  11. BREATHE to Understand©

    ERIC Educational Resources Information Center

    Swisa, Maxine

    2015-01-01

    BREATHE is an acronym for Breathe, Reflect, Empathize, Accept, Thank, Hearten, Engage. The addition of Understand allows for a holistic approach to living a healthy and balanced life both inside and outside the classroom. This paper took form as a result of my personal, spiritual journey, as well as my teaching practice. I noticed that the…

  12. Effects of breathing patterns and light exercise on linear and nonlinear heart rate variability.

    PubMed

    Weippert, Matthias; Behrens, Kristin; Rieger, Annika; Kumar, Mohit; Behrens, Martin

    2015-08-01

    Despite their use in cardiac risk stratification, the physiological meaning of nonlinear heart rate variability (HRV) measures is not well understood. The aim of this study was to elucidate effects of breathing frequency, tidal volume, and light exercise on nonlinear HRV and to determine associations with traditional HRV indices. R-R intervals, blood pressure, minute ventilation, breathing frequency, and respiratory gas concentrations were measured in 24 healthy male volunteers during 7 conditions: voluntary breathing at rest, and metronome guided breathing (0.1, 0.2 and 0.4 Hz) during rest, and cycling, respectively. The effect of physical load was significant for heart rate (HR; p < 0.001) and traditional HRV indices SDNN, RMSSD, lnLFP, and lnHFP (p < 0.01 for all). It approached significance for sample entropy (SampEn) and correlation dimension (D2) (p < 0.1 for both), while HRV detrended fluctuation analysis (DFA) measures DFAα1 and DFAα2 were not affected by load condition. Breathing did not affect HR but affected all traditional HRV measures. D2 was not affected by breathing; DFAα1 was moderately affected by breathing; and DFAα2, approximate entropy (ApEn), and SampEn were strongly affected by breathing. DFAα1 was strongly increased, whereas DFAα2, ApEn, and SampEn were decreased by slow breathing. No interaction effect of load and breathing pattern was evident. Correlations to traditional HRV indices were modest (r from -0.14 to -0.67, p < 0.05 to <0.01). In conclusion, while light exercise does not significantly affect short-time HRV nonlinear indices, respiratory activity has to be considered as a potential contributor at rest and during light dynamic exercise.

  13. Breath isoprene concentrations in persons undergoing general anesthesia and in healthy volunteers.

    PubMed

    Hornuss, Cyrill; Zagler, Armin; Dolch, Michael E; Wiepcke, Dirk; Praun, Siegfried; Boulesteix, Anne-Laure; Weis, Florian; Apfel, Christian C; Schelling, Gustav

    2012-12-01

    Human breath contains an abundance of volatile organic compounds (VOCs). Analysis of breath VOC may be used for diagnosis of various diseases or for on-line monitoring in anesthesia and intensive care. However, VOC concentrations largely depend on the breath sampling method and have a large inter-individual variability. For the development of breath tests, the influence of breath sampling methods and study subject characteristics on VOC concentrations has to be known. Therefore, we investigated the VOC isoprene in 62 study subjects during anesthesia and 16 spontaneously breathing healthy volunteers to determine (a) the influence of artificial and spontaneous ventilation and (b) the influence of study subject characteristics on breath isoprene concentrations. We used ion molecule reaction mass spectrometry for high-resolution breath-by-breath analysis of isoprene. We found that persons during anesthesia had significantly increased inspiratory and end-expiratory isoprene breath concentrations. Measured isoprene concentrations (median [first quartile-third quartile]) were in the anesthesia group: 54 [40-79] ppb (inspiratory) and 224 [171-309] ppb (end-expiratory), volunteer group: 14 [11-17] ppb (inspiratory) and 174 [124-202] ppb (end-expiratory). Higher end-tidal CO(2) concentrations in ventilated subjects were associated with higher expiratory isoprene levels. Furthermore, inspiratory and end-expiratory isoprene concentrations were correlated during anesthesia (r = 0.603, p < 0.001). Multivariate analysis showed that men had significantly higher end-expiratory isoprene concentrations than women. Rebreathing of isoprene from the anesthesia machine possibly accounts for the observed increase in isoprene in the anesthesia group.

  14. Effects of breathing patterns and light exercise on linear and nonlinear heart rate variability.

    PubMed

    Weippert, Matthias; Behrens, Kristin; Rieger, Annika; Kumar, Mohit; Behrens, Martin

    2015-08-01

    Despite their use in cardiac risk stratification, the physiological meaning of nonlinear heart rate variability (HRV) measures is not well understood. The aim of this study was to elucidate effects of breathing frequency, tidal volume, and light exercise on nonlinear HRV and to determine associations with traditional HRV indices. R-R intervals, blood pressure, minute ventilation, breathing frequency, and respiratory gas concentrations were measured in 24 healthy male volunteers during 7 conditions: voluntary breathing at rest, and metronome guided breathing (0.1, 0.2 and 0.4 Hz) during rest, and cycling, respectively. The effect of physical load was significant for heart rate (HR; p < 0.001) and traditional HRV indices SDNN, RMSSD, lnLFP, and lnHFP (p < 0.01 for all). It approached significance for sample entropy (SampEn) and correlation dimension (D2) (p < 0.1 for both), while HRV detrended fluctuation analysis (DFA) measures DFAα1 and DFAα2 were not affected by load condition. Breathing did not affect HR but affected all traditional HRV measures. D2 was not affected by breathing; DFAα1 was moderately affected by breathing; and DFAα2, approximate entropy (ApEn), and SampEn were strongly affected by breathing. DFAα1 was strongly increased, whereas DFAα2, ApEn, and SampEn were decreased by slow breathing. No interaction effect of load and breathing pattern was evident. Correlations to traditional HRV indices were modest (r from -0.14 to -0.67, p < 0.05 to <0.01). In conclusion, while light exercise does not significantly affect short-time HRV nonlinear indices, respiratory activity has to be considered as a potential contributor at rest and during light dynamic exercise. PMID:26187271

  15. Measuring Breathing Rate Variability by a Microprocessor Based Instrument in Newborn Infants

    PubMed Central

    Dolcourt, Jack; Younger, Steve

    1984-01-01

    A microprocessor-based instrument was developed to measure apnea (cessation of breathing) of prematurity. This instrument analyzes real-time respiratory data obtrained from either a standard cardiorespiratory monitor or from an end-tidal CO2 analyzer. The time between successive breaths (apneic duration) is computed and recorded. These intervals are displayed as a histogram in real-time on a computer terminal screen. The effects of pharmacologic treatment and nervous system maturation as relating to respiratory instability in premature infants is demonstrated.

  16. Study of airflow in the trachea of idealized model of human tracheobronchial airways during breathing cycle

    NASA Astrophysics Data System (ADS)

    Elcner, Jakub; Lizal, Frantisek; Jedelsky, Jan; Jicha, Miroslav

    2015-05-01

    The article deals with a numerical simulation and its verification by experiments in the trachea of idealized geometry of tracheobronchial airways by using unsteady RANS method. The breathing cycle was simulated by sinusoidal function with period of 4 seconds and tidal volume of 0.5 litres of air, which corresponds to breathing during resting condition. Results were compared with experiments measured by laser-Doppler velocimeter in eight points of four cross sections in the trachea. Model consists of the mouth cavity, larynx and tracheobronchial tree down to fourth generation of branching.

  17. Tidal heating of Ariel

    NASA Technical Reports Server (NTRS)

    Tittemore, William C.

    1990-01-01

    During evolution through the 4:1 commensurability early in the history of the Uranian system, over 3.8 billion years ago, tidal heating may have raised the internal temperature of Ariel by up to about 20 K; the internal temperature of Ariel may already have been high in virtue of both accretional and radiogenic heating. The additional increase in Ariel's temperature could then have triggered the geological activity that led to a late resurfacing, by decreasing lithospheric thickness and exacerbating thermal stresses on it to the point where observed cracks and faults formed.

  18. Conservation of tidal marshes

    SciTech Connect

    Daiber, F.C.

    1986-01-01

    This book is the first attempt to examine collectively the various uses and the consequences of marsh conservation efforts. Author Franklin Daiber emphasizes tidal marsh conservation from a holistic perspective rather than from the perspective of a single purpose or special economic interest. He addresses a topic receiving increasing attention, namely the concept of open marsh management as a means of controlling mosquito production without harmful effects on other marsh organisms. Topics considered include: water management; dikes, impoundments, ponds and ditches; reclaimed land and impoundments; ditching and ponding for mosquito control; sewage disposal and waste treatment; dredge material for wetland restoration; insecticides; oil pollution; and petroleum hydrocarbon interactions.

  19. Tidal Energy Research

    SciTech Connect

    Stelzenmuller, Nickolas; Aliseda, Alberto; Palodichuk, Michael; Polagye, Brian; Thomson, James; Chime, Arshiya; Malte, Philip

    2014-03-31

    This technical report contains results on the following topics: 1) Testing and analysis of sub-scale hydro-kinetic turbines in a flume, including the design and fabrication of the instrumented turbines. 2) Field measurements and analysis of the tidal energy resource and at a site in northern Puget Sound, that is being examined for turbine installation. 3) Conceptual design and performance analysis of hydro-kinetic turbines operating at high blockage ratio, for use for power generation and flow control in open channel flows.

  20. Yoga breathing, meditation, and longevity.

    PubMed

    Brown, Richard P; Gerbarg, Patricia L

    2009-08-01

    Yoga breathing is an important part of health and spiritual practices in Indo-Tibetan traditions. Considered fundamental for the development of physical well-being, meditation, awareness, and enlightenment, it is both a form of meditation in itself and a preparation for deep meditation. Yoga breathing (pranayama) can rapidly bring the mind to the present moment and reduce stress. In this paper, we review data indicating how breath work can affect longevity mechanisms in some ways that overlap with meditation and in other ways that are different from, but that synergistically enhance, the effects of meditation. We also provide clinical evidence for the use of yoga breathing in the treatment of depression, anxiety, post-traumatic stress disorder, and for victims of mass disasters. By inducing stress resilience, breath work enables us to rapidly and compassionately relieve many forms of suffering.

  1. TIDAL AND TIDALLY AVERAGED CIRCULATION CHARACTERISTICS OF SUISUN BAY, CALIFORNIA.

    USGS Publications Warehouse

    Smith, Lawrence H.; Cheng, Ralph T.

    1987-01-01

    Availability of extensive field data permitted realistic calibration and validation of a hydrodynamic model of tidal circulation and salt transport for Suisun Bay, California. Suisun Bay is a partially mixed embayment of northern San Francisco Bay located just seaward of the Sacramento-San Joaquin Delta. The model employs a variant of an alternating direction implicit finite-difference method to solve the hydrodynamic equations and an Eulerian-Lagrangian method to solve the salt transport equation. An upwind formulation of the advective acceleration terms of the momentum equations was employed to avoid oscillations in the tidally averaged velocity field produced by central spatial differencing of these terms. Simulation results of tidal circulation and salt transport demonstrate that tides and the complex bathymetry determine the patterns of tidal velocities and that net changes in the salinity distribution over a few tidal cycles are small despite large changes during each cycle.

  2. Rapid shallow breathing index

    PubMed Central

    Karthika, Manjush; Al Enezi, Farhan A.; Pillai, Lalitha V.; Arabi, Yaseen M.

    2016-01-01

    Predicting successful liberation of patients from mechanical ventilation has been a focus of interest to clinicians practicing in intensive care. Various weaning indices have been investigated to identify an optimal weaning window. Among them, the rapid shallow breathing index (RSBI) has gained wide use due to its simple technique and avoidance of calculation of complex pulmonary mechanics. Since its first description, several modifications have been suggested, such as the serial measurements and the rate of change of RSBI, to further improve its predictive value. The objective of this paper is to review the utility of RSBI in predicting weaning success. In addition, the use of RSBI in specific patient populations and the reported modifications of RSBI technique that attempt to improve the utility of RSBI are also reviewed. PMID:27512505

  3. Rapid shallow breathing index.

    PubMed

    Karthika, Manjush; Al Enezi, Farhan A; Pillai, Lalitha V; Arabi, Yaseen M

    2016-01-01

    Predicting successful liberation of patients from mechanical ventilation has been a focus of interest to clinicians practicing in intensive care. Various weaning indices have been investigated to identify an optimal weaning window. Among them, the rapid shallow breathing index (RSBI) has gained wide use due to its simple technique and avoidance of calculation of complex pulmonary mechanics. Since its first description, several modifications have been suggested, such as the serial measurements and the rate of change of RSBI, to further improve its predictive value. The objective of this paper is to review the utility of RSBI in predicting weaning success. In addition, the use of RSBI in specific patient populations and the reported modifications of RSBI technique that attempt to improve the utility of RSBI are also reviewed. PMID:27512505

  4. Breathing zone air sampler

    DOEpatents

    Tobin, John

    1989-01-01

    A sampling apparatus is provided which comprises a sampler for sampling air in the breathing zone of a wearer of the apparatus and a support for the sampler preferably in the form of a pair of eyeglasses. The sampler comprises a sampling assembly supported on the frame of the eyeglasses and including a pair of sample transport tubes which are suspended, in use, centrally of the frame so as to be disposed on opposite sides of the nose of the wearer and which each include an inlet therein that, in use, is disposed adjacent to a respective nostril of the nose of the wearer. A filter holder connected to sample transport tubes supports a removable filter for filtering out particulate material in the air sampled by the apparatus. The sample apparatus is connected to a pump for drawing air into the apparatus through the tube inlets so that the air passes through the filter.

  5. Growth of breath figures

    NASA Astrophysics Data System (ADS)

    Beysens, D.; Knobler, C. M.

    1986-09-01

    Measurements are reported of the growth of breath figures, the patterns that form when a vapor is condensed onto a cold surface. Water vapor was condensed on glass slides and the pattern was studied by direct observation and light scattering as a function of the contact angle theta, flux F, degree of supersaturation ΔT, and time t. When theta=0°, a uniform layer forms whose thickness grows as t at constant F and ΔT. For theta=90°, droplets are formed; at constant F and T, the radius of an isolated droplet grows as t0.23, but, as a result of coalescences, the average droplet radius grows as t0.75. The droplet growth process is self-similar-coalescences simply rescale the distances and leave the basic droplet pattern unaltered.

  6. Tidal Pools--Miniature Oceans

    ERIC Educational Resources Information Center

    Plake, Linda Perry

    1977-01-01

    A comprehensive discussion of the biological activity in tidal pools is provided. The importance of environmental factors such as oxygen supply, temperature, salinity, and light is detailed. Plants and animals that might be found in a tidal pool are identified and described. (BT)

  7. Design and Evaluation of an Intelligent Remote Tidal Volume Variability Monitoring System in E-Health Applications.

    PubMed

    Fekr, Atena Roshan; Radecka, Katarzyna; Zilic, Zeljko

    2015-09-01

    A reliable long-term monitoring and diagnosis of breath disorders at an early stage provides an improvement of medical act, life expectancy, and quality of life while decreasing the costs of treatment and medical services. Therefore, a real-time unobtrusive monitoring of respiration patterns, as well as breath parameters, is a critical need in medical applications. In this paper, we propose an intelligent system for patient home care, capable of measuring respiration rate and tidal volume variability via a wearable sensing technology. The proposed system is designed particularly for the goal of diagnosis and treatment in patients with pathological breathing, e.g., respiratory complications after surgery or sleep disorders. The complete system was comprised of wearable calibrated accelerometer sensor, Bluetooth low energy, and cloud database. The experiments are conducted with eight subjects and the overall error in respiration rate calculation is obtained 0.29%±0.33% considering SPR-BTA spirometer as the reference. We also introduce a method for tidal volume variability estimation while validated using Pearson correlation. Furthermore, since it is essential to detect the critical events resulted from sudden rise or fall in per breath tidal volume of the patients, we provide a technique to automatically find the accurate threshold values based on each individual breath characteristics. Therefore, the system is able to detect the major changes, precisely by more than 98%, and provide immediate feedback such as sound alarm for round-the-clock respiration monitoring. PMID:26087508

  8. Design and Evaluation of an Intelligent Remote Tidal Volume Variability Monitoring System in E-Health Applications.

    PubMed

    Fekr, Atena Roshan; Radecka, Katarzyna; Zilic, Zeljko

    2015-09-01

    A reliable long-term monitoring and diagnosis of breath disorders at an early stage provides an improvement of medical act, life expectancy, and quality of life while decreasing the costs of treatment and medical services. Therefore, a real-time unobtrusive monitoring of respiration patterns, as well as breath parameters, is a critical need in medical applications. In this paper, we propose an intelligent system for patient home care, capable of measuring respiration rate and tidal volume variability via a wearable sensing technology. The proposed system is designed particularly for the goal of diagnosis and treatment in patients with pathological breathing, e.g., respiratory complications after surgery or sleep disorders. The complete system was comprised of wearable calibrated accelerometer sensor, Bluetooth low energy, and cloud database. The experiments are conducted with eight subjects and the overall error in respiration rate calculation is obtained 0.29%±0.33% considering SPR-BTA spirometer as the reference. We also introduce a method for tidal volume variability estimation while validated using Pearson correlation. Furthermore, since it is essential to detect the critical events resulted from sudden rise or fall in per breath tidal volume of the patients, we provide a technique to automatically find the accurate threshold values based on each individual breath characteristics. Therefore, the system is able to detect the major changes, precisely by more than 98%, and provide immediate feedback such as sound alarm for round-the-clock respiration monitoring.

  9. DTP: a Tidal Power Revolution

    NASA Astrophysics Data System (ADS)

    Steijn, Robbert; Hulsbergen, Kees; van Banning, Gijs

    2013-04-01

    Tidal power can significantly contribute to the global mix of sustainable energy resources. It is climate-independent, fully predictable, and if designed properly it is environmentally friendly and socio-economically feasible. The two traditional methods of exploiting tidal power are Tidal Barrage and Tidal Stream. This study deals with an alternative Third Method, named Dynamic Tidal Power (DTP), which contrary to the other methods, utilises the oscillating character of tides, or more precisely: the acceleration inherent to unsteady flow. DTP uses a long dam (order of tens of km's), attached and perpendicular to a coast with shore-parallel tidal currents, to generate a local hydraulic head. This time-varying head is used to generate electricity in a more or less standard way with turbines and generators placed in (many) dam openings. For a first impression only: typical installed power for one DTP is more than 10 GW with electricity output > 2.1010 kWh/y and construction costs of ca. 1 EUR/W. The physical mechanism behind the creation of the head has been described by Hulsbergen e.a., (2012). Following a heuristic approach based on analytical work done by Kolkman (unpubl.), and output from numerical tidal models, Hulsbergen (2012) concluded that the maximum head (near the coast), is: hmax = 6,8*?*D*Vmax/(g*T), with Vmax the maximum alongshore flow velocity during the tidal cycle, T the tidal period and D the length of dam. Such simple relationship was also found by Mei (2012) who made a rigorous analysis of a process-based model. After a thorough reflection on DTP, this study will first check the above formula for hmax , by comparing its predictions with the output from various numerical tidal models. Any differences will be analysed in the study through an evaluation of the dominant physical processes and the schematisations inherent to both the analytical and the numerical models. The study will also address the effect of the openings in the dam, as well as the

  10. Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating

    PubMed Central

    Mullins, Kristina; Goldblatt, Colin; Meadows, Victoria S.; Kasting, James F.; Heller, René

    2013-01-01

    Abstract Traditionally, stellar radiation has been the only heat source considered capable of determining global climate on long timescales. Here, we show that terrestrial exoplanets orbiting low-mass stars may be tidally heated at high-enough levels to induce a runaway greenhouse for a long-enough duration for all the hydrogen to escape. Without hydrogen, the planet no longer has water and cannot support life. We call these planets “Tidal Venuses” and the phenomenon a “tidal greenhouse.” Tidal effects also circularize the orbit, which decreases tidal heating. Hence, some planets may form with large eccentricity, with its accompanying large tidal heating, and lose their water, but eventually settle into nearly circular orbits (i.e., with negligible tidal heating) in the habitable zone (HZ). However, these planets are not habitable, as past tidal heating desiccated them, and hence should not be ranked highly for detailed follow-up observations aimed at detecting biosignatures. We simulated the evolution of hypothetical planetary systems in a quasi-continuous parameter distribution and found that we could constrain the history of the system by statistical arguments. Planets orbiting stars with masses<0.3 MSun may be in danger of desiccation via tidal heating. We have applied these concepts to Gl 667C c, a ∼4.5 MEarth planet orbiting a 0.3 MSun star at 0.12 AU. We found that it probably did not lose its water via tidal heating, as orbital stability is unlikely for the high eccentricities required for the tidal greenhouse. As the inner edge of the HZ is defined by the onset of a runaway or moist greenhouse powered by radiation, our results represent a fundamental revision to the HZ for noncircular orbits. In the appendices we review (a) the moist and runaway greenhouses, (b) hydrogen escape, (c) stellar mass-radius and mass-luminosity relations, (d) terrestrial planet mass-radius relations, and (e) linear tidal theories. Key Words: Extrasolar terrestrial

  11. Validation of Respiratory Inductance Plethysmography for Measuring Tidal Volume in Swine

    PubMed Central

    Su, Zhenbo; Oto, Jun; Wang, Jingwen; Kimball, William R; Chenelle, Christopher T; Kacmarek, Robert M; King, David R; Jiang, Yandong; Duggan, Michael J

    2015-01-01

    Measuring tidal volume (VT) in nonintubated swine or swine with leaking breathing circuits is challenging. The aim of this study was to validate respiratory inductance plethysmography (RIP) for measuring VT in swine that are comparable in size to adult humans. To determine calibration curves, VT and RIP readings were obtained from anesthetized swine (n = 8; weight, 46–50 kg) during positive-pressure (mechanical) ventilation and spontaneous breathing. For positive-pressure ventilation, 6 pigs were mechanically ventilated by using the pressure-control mode. The 2 pigs in the spontaneously breathing cohort each received a single intravenous bolus dose of propofol to abolish spontaneous breathing; VT was measured during gradual return of their respiratory drive. A flow–volume sensor was placed between the proximal end of the endotracheal tube and breathing circuit for the recording of inspiratory and expiratory VT. RIP readings were recorded by using 2 bands, which simultaneously measured ribcage and abdominal excursions. The data revealed that VT was linearly correlated with the movements of both ribcage and abdomen as measured by using plethysmography over a large range of tidal volume (44 to 1065 mL). In addition, the intercept of the linear equation was small or even negative during spontaneous breathing but increased significantly (maximum, 145 mL, 59.2 ± 35.1 mL) during positive pressure ventilation. Our results indicate that VT in swine can be calculated by using a simple univariate linear regression equation with RIP readings obtained during either mechanical ventilation or spontaneous breathing. PMID:26141447

  12. Validation of Respiratory Inductance Plethysmography for Measuring Tidal Volume in Swine.

    PubMed

    Su, Zhenbo; Oto, Jun; Wang, Jingwen; Kimball, William R; Chenelle, Christopher T; Kacmarek, Robert M; King, David R; Jiang, Yandong; Duggan, Michael J

    2015-06-01

    Measuring tidal volume (VT) in nonintubated swine or swine with leaking breathing circuits is challenging. The aim of this study was to validate respiratory inductance plethysmography (RIP) for measuring VT in swine that are comparable in size to adult humans. To determine calibration curves, VT and RIP readings were obtained from anesthetized swine (n = 8; weight, 46-50 kg) during positive-pressure (mechanical) ventilation and spontaneous breathing. For positive-pressure ventilation, 6 pigs were mechanically ventilated by using the pressure-control mode. The 2 pigs in the spontaneously breathing cohort each received a single intravenous bolus dose of propofol to abolish spontaneous breathing; VT was measured during gradual return of their respiratory drive. A flow-volume sensor was placed between the proximal end of the endotracheal tube and breathing circuit for the recording of inspiratory and expiratory VT. RIP readings were recorded by using 2 bands, which simultaneously measured ribcage and abdominal excursions. The data revealed that VT was linearly correlated with the movements of both ribcage and abdomen as measured by using plethysmography over a large range of tidal volume (44 to 1065 mL). In addition, the intercept of the linear equation was small or even negative during spontaneous breathing but increased significantly (maximum, 145 mL, 59.2 ± 35.1 mL) during positive pressure ventilation. Our results indicate that VT in swine can be calculated by using a simple univariate linear regression equation with RIP readings obtained during either mechanical ventilation or spontaneous breathing.

  13. Anatomic and Pathologic Variability During Radiotherapy for a Hybrid Active Breath-Hold Gating Technique

    SciTech Connect

    Glide-Hurst, Carri K.; Gopan, Ellen; Hugo, Geoffrey D.

    2010-07-01

    Purpose: To evaluate intra- and interfraction variability of tumor and lung volume and position using a hybrid active breath-hold gating technique. Methods and Materials: A total of 159 repeat normal inspiration active breath-hold CTs were acquired weekly during radiotherapy for 9 lung cancer patients (12-21 scans per patient). A physician delineated the gross tumor volume (GTV), lungs, and spinal cord on the first breath-hold CT, and contours were propagated semiautomatically. Intra- and interfraction variability of tumor and lung position and volume were evaluated. Tumor centroid and border variability were quantified. Results: On average, intrafraction variability of lung and GTV centroid position was <2.0 mm. Interfraction population variability was 3.6-6.7 mm (systematic) and 3.1-3.9 mm (random) for the GTV centroid and 1.0-3.3 mm (systematic) and 1.5-2.6 mm (random) for the lungs. Tumor volume regressed 44.6% {+-} 23.2%. Gross tumor volume border variability was patient specific and demonstrated anisotropic shape change in some subjects. Interfraction GTV positional variability was associated with tumor volume regression and contralateral lung volume (p < 0.05). Inter-breath-hold reproducibility was unaffected by time point in the treatment course (p > 0.1). Increases in free-breathing tidal volume were associated with increases in breath-hold ipsilateral lung volume (p < 0.05). Conclusions: The breath-hold technique was reproducible within 2 mm during each fraction. Interfraction variability of GTV position and shape was substantial because of tumor volume and breath-hold lung volume change during therapy. These results support the feasibility of a hybrid breath-hold gating technique and suggest that online image guidance would be beneficial.

  14. Galileo's tidal theory.

    PubMed

    Naylor, Ron

    2007-03-01

    The aim of Galileo's tidal theory was to show that the tides were produced entirely by the earth's motion and thereby to demonstrate the physical truth of Copernicanism. However, in the Dialogue Concerning the Two Chief World Systems Galileo did not explain some of the most significant aspects of the theory completely. As a consequence, the way the theory works has long been disputed. Though there exist a number of interpretations in the literature, the most widely accepted are based on ideas that are not explicitly articulated by Galileo in the Dialogue. This essay attempts to understand the way the theory functions in terms of Galilean physics. It is an interpretation of the theory based solely on Galileo's arguments--and one that reveals it to have had some unrecognized consequences. This interpretation indicates that Galileo's theory would not have worked in the manner he described in the Dialogue. PMID:17539198

  15. Galileo's tidal theory.

    PubMed

    Naylor, Ron

    2007-03-01

    The aim of Galileo's tidal theory was to show that the tides were produced entirely by the earth's motion and thereby to demonstrate the physical truth of Copernicanism. However, in the Dialogue Concerning the Two Chief World Systems Galileo did not explain some of the most significant aspects of the theory completely. As a consequence, the way the theory works has long been disputed. Though there exist a number of interpretations in the literature, the most widely accepted are based on ideas that are not explicitly articulated by Galileo in the Dialogue. This essay attempts to understand the way the theory functions in terms of Galilean physics. It is an interpretation of the theory based solely on Galileo's arguments--and one that reveals it to have had some unrecognized consequences. This interpretation indicates that Galileo's theory would not have worked in the manner he described in the Dialogue.

  16. Lung function, breathing pattern, and gas exchange in interstitial lung disease.

    PubMed Central

    Javaheri, S; Sicilian, L

    1992-01-01

    BACKGROUND: The aim of this study was to determine the relation between the severity of abnormalities in ventilatory function tests and tidal breathing pattern and gas exchange indices in interstitial lung disease. METHODS: Pulmonary function, ventilation, carbon dioxide production, oxygen consumption, arterial blood gas tensions, and pH were measured during resting steady state conditions in 60 patients with proved interstitial lung disease. Patients were categorised by forced vital capacity (FVC) (percentage of predicted values) as having a mild, moderate, or severe restrictive defect with means (SD) of 71% (4%), 57% (4%), and 41% (7%) of predicted values, respectively. RESULTS: FVC varied from 29% to 79% of predicted values and from 0.99 l to 4.32 l. The two measurements of FVC correlated strongly with most static lung volumes and with transfer factor for carbon monoxide. Mean respiratory rates (per minute) and tidal volumes (ml) were 17 (4) and 484 (131), 20 (4) and 460 (139), and 23 (5) and 377 (109) in mild, moderate, and severe restrictive defects, respectively. FVC correlated negatively with respiratory rate and positively with tidal volume. Arterial carbon dioxide tension ranged from 30 to 49 mm Hg; only two patients were hypercapnic. Mean arterial oxygen tensions were not significantly different among the three groups, and there were no significant correlations between forced expiratory volume in one second or FVC and arterial carbon dioxide tension or carbon dioxide production. CONCLUSION: Low values of FVC were associated with increased respiratory rate and decreased tidal volume; this pattern of breathing mimics external elastic loading, suggesting that mechanoreceptors may contribute to the rapid and shallow pattern of breathing in interstitial lung disease. Hypercapnia seems to be rare in interstitial lung disease even when functional impairment is severe and tidal volume is small. The increased respiratory rate is important in maintaining adequate

  17. A nomogram for assessment of breathing patterns during treadmill exercise

    PubMed Central

    Naranjo, J; Centeno, R; Galiano, D; Beaus, M

    2005-01-01

    Objective: To assess the breathing patterns of trained athletes under different conditions. The hypothesis is that the breathing pattern during a progressive treadmill exercise is independent of the protocol, at least in healthy people, and can be assessed using a nomogram. Methods: A total of 43 male and 21 female athletes from different sports were studied. They performed one of two different protocols (steps or ramp) on a treadmill. The two protocols started at the same speed and had the same rate of increase in work. During the test, the expired air was analysed for CO2 and O2. Ventilation (VE) was continuously recorded, and tidal volume (Vt) and breathing frequency (BF) at the same intensity were analysed for both protocols, as well as Vt/Ti and Ti/Ttot. Results: No significant differences were observed in Vt and BF between the two protocols in either the men or women at any level (confidence intervals up to 0.958 in all the groups). Ti/Ttot remained constant, and all increases in VE were strongly related to the respective increases in Vt/Ti. Plots of data for men and women showed a curvilinear relation between Vt and BF which could be fitted with an exponential function with a strong correlation (R2 = 0.98 for men and 0.97 for women). Conclusions: Graphic expression of Vt v BF is a useful nomogram for the routine assessment of ventilatory response during exercise in healthy trained subjects. PMID:15665202

  18. Automated 4D lung computed tomography reconstruction during free breathing for conformal radiation therapy

    NASA Astrophysics Data System (ADS)

    El Naqa, Issam M.; Low, Daniel A.; Christensen, Gary E.; Parikh, Parag J.; Song, Joo Hyun; Nystrom, Michelle M.; Lu, Wei; Deasy, Joseph O.; Hubenschmidt, James P.; Wahab, Sasha H.; Mutic, Sasa; Singh, Anurag K.; Bradley, Jeffrey D.

    2004-04-01

    We are developing 4D-CT to provide breathing motion information (trajectories) for radiation therapy treatment planning of lung cancer. Potential applications include optimization of intensity-modulated beams in the presence of breathing motion and intra-fraction target volume margin determination for conformal therapy. The images are acquired using a multi-slice CT scanner while the patient undergoes simultaneous quantitative spirometry. At each couch position, the CT scanner is operated in ciné mode and acquires up to 15 scans of 12 slices each. Each CT scan is associated with the measured tidal volume for retrospective reconstruction of 3D CT scans at arbitrary tidal volumes. The specific tasks of this project involves the development of automated registration of internal organ motion (trajectories) during breathing. A modified least-squares based optical flow algorithm tracks specific features of interest by modifying the eigenvalues of gradient matrix (gradient structural tensor). Good correlations between the measured motion and spirometry-based tidal volume are observed and evidence of internal hysteresis is also detected.

  19. Tidal influence within Pennsylvanian sandstones

    SciTech Connect

    Archer, A.W. )

    1991-08-01

    Within Pennsylvanian-age strata of the Illinois basin, large-scale linear sand bodies have been previously interpreted as fluvial and deltaic in origin. Nonetheless, analyses of fine-scale sedimentology and bed forms within such sandstones and the associated shales indicate that tidal processes greatly influenced the depositional environments within such lithofacies. Recent work on Mid-Continent Pennsylvanian-age sandstones indicates the occurrence of similar depositional environments. Based upon the pervasive tidal influence observed within such strata, environmental analogs other than fluvial and deltaic bear consideration. In general, tidally influenced estuarine models seem particularly appropriate. Within such settings, the changeover from a fluvially dominated deposystem to tidally influenced estuary occurs during transgressive phases. Despite the tidal influence that can be interpreted from the sedimentology, the strata contain few, if any, marine indicators because of the low salinities that occurred during deposition. Ongoing work in the Mid-Continent indicates that Morrowan, Atokan, Desmoinesian, Missourian, and Virgilian sands share a number of similarities with the tidally influenced environments delineated in the Illinois basin studies. Thus a tidal/estuarine interpretation might be a generalizable model for many Pennsylvanian sandstones. In addition, enhanced understanding of the siliciclastic parts of Mid-Continent cyclothems provides a more useful framework for documentation of carbonate/siliciclastic interrelationships. Oscillations of carbonate/siliciclastic environments may be more readily explainable by climatic cycles rather than by traditionally popular depth-related facies models.

  20. Tidal amplification of seabed light

    NASA Astrophysics Data System (ADS)

    Bowers, D. G.; Brubaker, J. M.

    2010-09-01

    Because solar irradiance decreases approximately exponentially with depth in the sea, the increase in irradiance at the seabed from mid to low tide is greater than the decrease from mid to high tide. Summed over a day, this can lead to a net amplification of seabed irradiance in tidal waters compared to nontidal waters with the same mean depth and transparency. In this paper, this effect is quantified by numerical and analytical integration of the Lambert-Beer equation to derive the ratio of daily total seabed irradiance with and without a tide. Greatest amplification occurs in turbid water with large tidal range and low tide occurring at noon. The theoretical prediction is tested against observations of seabed irradiance in the coastal waters of North Wales where tidal amplification of seabed light by up to a factor of 7 is both observed and predicted. Increasing the strength of tidal currents tends to increase the turbidity of the water and hence reduce the light reaching the seabed, but this effect is made less by increasing tidal amplification, especially when low water is in the middle of the day. The ecological implications of tidal amplification are discussed. The productivity of benthic algae will be greater than that predicted by simple models which calculate seabed irradiance using the mean depth of water alone. Benthic algae are also able to live at greater depths in tidal waters than in nontidal waters with the same transparency.

  1. Correlations between blood glucose and breath components from portable gas sensors and PTR-TOF-MS.

    PubMed

    Righettoni, M; Schmid, A; Amann, A; Pratsinis, S E

    2013-09-01

    Acetone is one of the most abundant volatile compounds in the human breath and might be important for monitoring diabetic patients. Here, a portable acetone sensor consisting of flame-made, nanostructured, Si-doped WO3 sensing films was used to analyse the end tidal fraction of the breath (collected in Tedlar bags) from eight healthy volunteers after overnight fasting (morning) and after lunch (afternoon). After breath sampling, the gaseous components were also analysed by proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS), and each person's blood glucose level was measured. The portable sensor accurately detected the presence of acetone with fast response/recovery times (<12 s) and a high signal-to-noise ratio. Statistical analysis of the relationship between the PTR-TOF-MS measurements of breath gases (e.g., acetone, isoprene, ethanol and methanol), sensor response and the blood glucose level was performed for both sampling periods. The best correlations were found after overnight fasting (morning): in particular, between blood glucose level and breath acetone (Pearson's 0.98 and Spearman's 0.93). Whereas the portable sensor response correlated best with the blood glucose (Pearson's 0.96 and Spearman's 0.81) and breath acetone (Pearson's 0.92 and Spearman's 0.69). PMID:23959908

  2. Slow breathing and emotions associated with odor-induced autobiographical memories.

    PubMed

    Masaoka, Yuri; Sugiyama, Haruko; Katayama, Atsushi; Kashiwagi, Mitsuyoshi; Homma, Ikuo

    2012-05-01

    An important feature of olfactory perception is its dependence on respiratory activity. By inspiration, olfactory information ascends directly to olfactory-related limbic structures. Therefore, every breath with odor molecules activates these limbic areas associated with emotional experience and memory retrieval. We tested whether odors associated with autobiographical memories can trigger pleasant emotional experiences and whether respiration changes during stimulation with these odors. During presentation of odors related to autobiographical memories and control odors, we measured minute ventilation, tidal volume, respiratory frequency, O2 consumption, and end tidal CO2 concentration. Findings showed that autobiographical memory retrieval was associated with increasing tidal volume and decreasing respiratory frequency more than during presentation of control odors. Subjective feelings such as emotional arousal during retrieval of the memory, arousal level of the memory itself, or pleasantness and familiarity toward the odor evoked by autobiographical memory were more specific emotional responses compared with those related to control odors. In addition, high trait anxiety subjects responded with a stronger feeling of being taken back in time and had high arousal levels with tidal volume increases. We discussed assumptions regarding how deep and slow breathing is related to pleasantness and comfortableness of an autobiographical memory. PMID:22230171

  3. Slow breathing and emotions associated with odor-induced autobiographical memories.

    PubMed

    Masaoka, Yuri; Sugiyama, Haruko; Katayama, Atsushi; Kashiwagi, Mitsuyoshi; Homma, Ikuo

    2012-05-01

    An important feature of olfactory perception is its dependence on respiratory activity. By inspiration, olfactory information ascends directly to olfactory-related limbic structures. Therefore, every breath with odor molecules activates these limbic areas associated with emotional experience and memory retrieval. We tested whether odors associated with autobiographical memories can trigger pleasant emotional experiences and whether respiration changes during stimulation with these odors. During presentation of odors related to autobiographical memories and control odors, we measured minute ventilation, tidal volume, respiratory frequency, O2 consumption, and end tidal CO2 concentration. Findings showed that autobiographical memory retrieval was associated with increasing tidal volume and decreasing respiratory frequency more than during presentation of control odors. Subjective feelings such as emotional arousal during retrieval of the memory, arousal level of the memory itself, or pleasantness and familiarity toward the odor evoked by autobiographical memory were more specific emotional responses compared with those related to control odors. In addition, high trait anxiety subjects responded with a stronger feeling of being taken back in time and had high arousal levels with tidal volume increases. We discussed assumptions regarding how deep and slow breathing is related to pleasantness and comfortableness of an autobiographical memory.

  4. Effect of ventilation frequency and tidal volume on pleural space thickness in rabbits.

    PubMed

    Wang, P M; Lai-Fook, S J

    1993-10-01

    The thickness of the pleural space was measured by fluorescence video-microscopy during mechanical ventilation in anesthetized paralyzed rabbits. A transparent parietal pleural window was made in the fourth or sixth intercostal space near midchest by dissection of intercostal muscle and endothoracic fascia. Fluorescence-labeled (fluorescein isothiocyanate) dextran solution (1 ml) was injected into the pleural space via a rib capsule and allowed to mix with the pleural liquid. With the rabbit in the left lateral decubitus position and the pleural window superior, the light emitted from the pleural liquid through the pleural window was measured through the videomicroscope. Both ventilation frequency and tidal volume were varied. Pleural space thickness was determined by in vitro calibration of the pleural liquid at the end of the experiment. At a frequency of 40 breaths/min and a tidal volume of 20 ml, pleural space thickness averaged 35 +/- 15 (SD) microns (n = 7). When frequency was reduced to 8 breaths/min, this value was reduced by 40% to 22 +/- 11 microns. A reduction in tidal volume from 20 to 6 ml at a frequency of 40 breaths/min produced a similar reduction in pleural space thickness. During apnea, pleural space thickness averaged 11 +/- 3 microns. Cardiogenic motion had no measurable effect on pleural space thickness. The increased pleural space thickness with ventilation might serve to reduce the power dissipated due to sliding of the lung relative to the chest wall. Results support the concept of lubrication as the primary function of the pleural space.

  5. Enceladus' tidal dissipation revisited

    NASA Astrophysics Data System (ADS)

    Tobie, Gabriel; Behounkova, Marie; Choblet, Gael; Cadek, Ondrej; Soucek, Ondrej

    2016-10-01

    A series of chemical and physical evidence indicates that the intense activity at Enceladus' South Pole is related to a subsurface salty water reservoir underneath the tectonically active ice shell. The detection of a significant libration implies that this water reservoir is global and that the average ice shell thickness is about 20-25km (Thomas et al. 2016). The interpretation of gravity and topography data further predicts large variations in ice shell thickness, resulting in a shell potentially thinner than 5 km in the South Polar Terrain (SPT) (Cadek et al. 2016). Such an ice shell structure requires a very strong heat source in the interior, with a focusing mechanism at the SPT. Thermal diffusion through the ice shell implies that at least 25-30 GW is lost into space by passive diffusion, implying a very efficient dissipation mechanism in Enceladus' interior to maintain such an ocean/ice configuration thermally stable.In order to determine in which conditions such a large dissipation power may be generated, we model the tidal response of Enceladus including variable ice shell thickness. For the rock core, we consider a wide range of rheological parameters representative of water-saturated porous rock materials. We demonstrate that the thinning toward the South Pole leads to a strong increase in heat production in the ice shell, with a optimal thickness obtained between 1.5 and 3 km, depending on the assumed ice viscosity. Our results imply that the heat production in the ice shell within the SPT may be sufficient to counterbalance the heat loss by diffusion and to power eruption activity. However, outside the SPT, a strong dissipation in the porous core is required to counterbalance the diffusive heat loss. We show that about 20 GW can be generated in the core, for an effective viscosity of 1012 Pa.s, which is comparable to the effective viscosity estimated in water-saturated glacial tills on Earth. We will discuss the implications of this revisited tidal

  6. Standardization of exhaled breath condensate (EBC) collection using a feedback regulated breathing pattern

    EPA Science Inventory

    Collection of exhaled breath condensate (EBC) fluid by cooling of expired breath is a potentially valuable approach for the detection of biomarkers associated with disease or exposure to xenobiotics. EBC is generally collected using unregulated breathing patterns, perceived to el...

  7. Effects of changes in level and pattern of breathing on the sensation of dyspnea.

    PubMed

    Chonan, T; Mulholland, M B; Altose, M D; Cherniack, N S

    1990-10-01

    Breathing during hypercapnia is determined by reflex mechanisms but may also be influenced by respiratory sensations. The present study examined the effects of voluntary changes in level and pattern of breathing on the sensation of dyspnea at a constant level of chemical drive. Studies were carried out in 15 normal male subjects during steady-state hypercapnia at an end-tidal PCO2 of 50 Torr. The intensity of dyspnea was rated on a Borg category scale. In one experiment (n = 8), the level of ventilation was increased or decreased from the spontaneously adopted level (Vspont). In another experiment (n = 9), the minute ventilation was maintained at the level spontaneously adopted at PCO2 of 50 Torr and breathing frequency was increased or decreased from the spontaneously adopted level (fspont) with reciprocal changes in tidal volume. The intensity of dyspnea (expressed as percentage of the spontaneous breathing level) correlated with ventilation (% Vspont) negatively at levels below Vspont (r = -0.70, P less than 0.001) and positively above Vspont (r = 0.80, P less than 0.001). At a constant level of ventilation, the intensity of dyspnea correlated with breathing frequency (% fspont) negatively at levels below fspont (r = -0.69, P less than 0.001) and positively at levels above fspont (r = 0.75, P less than 0.001). These results indicate that dyspnea intensifies when the level or pattern of breathing is voluntarily changed from the spontaneously adopted level. This is consistent with the possibility that ventilatory responses to changes in chemical drive may be regulated in part to minimize the sensations of respiratory effort and discomfort.

  8. Tidal volume measurements in infants: Opto-electronic plethysmography versus pneumotachograph.

    PubMed

    Reinaux, Cyda Maria Albuquerque; Aliverti, Andrea; da Silva, Lívia Gabriely Melo; da Silva, Rafael Justino; Gonçalves, Juliane Neves; Noronha, Jessica Brito; Filho, José Eulálio Cabral; de Andrade, Armèle Dornelas; de Amorim Britto, Murilo Carlos

    2016-08-01

    Tidal breathing measurements by Opto-Electronic Plethysmography (OEP) has been reported for infants limited to protocols with two chest wall compartments. Standard protocol for the analysis of adults, with three compartments of chest wall, has been unavailable for analysis of infants. We aimed to study the agreement of simultaneous measurements of tidal volume by OEP (VT,OEP ) and a heated pneumotachograph (PNT) (VT,PNT ) performed during sleeping in 20 infants (gestational age 35.1 ± 4.6 weeks) at 3-4 months postconceptual age with a three compartment protocol. From PNT and OEP measurements, tidal volume corrected (VT,PNT ) for ambient conditions were calculated with a total number of 200 breaths. The two methods were in good agreement with tidal volume mean difference of 0.02 ml and limit of agreement -4.11 to 4.08 ml (95%CI), no relationship was found between differences and means of OEP and PNT measurements. Pulmonary rib cage, abdominal rib cage and abdomen contributed by 12.4 ± 9.7%, 5.2 ± 5.1%, and 82.4 ± 11.4% to VT,OEP , respectively. The OEP experimental protocol based on 52 markers and a three-compartment model of the chest wall could be used in spontaneously sleeping infants. Pediatr Pulmonol. 2016;51:850-857. © 2016 Wiley Periodicals, Inc.

  9. Short-term potentiation of breathing in humans.

    PubMed

    Fregosi, R F

    1991-09-01

    The purpose of this study was to determine if the increase in ventilation induced by hypoxic stimulation of the carotid bodies (CB) persists after cessation of the stimulus in humans. I reasoned that a short-term potentiation (STP) of breathing, sometimes called an "afterdischarge," could be unmasked by combining hypoxia with exercise, because ventilation increases synergistically under these conditions. Seven young healthy men performed mild bicycle exercise (30% peak power) while breathing O2 for 1.5 min ("control" state), and their CB were then stimulated by 1.5 min of hypoxic exercise (10% O2--balance N2). CB stimulation was then terminated by changing the inspirate back to O2 as exercise continued. Inspiratory and expiratory duration (TI and TE) and inspiratory flow and its time integral [tidal volume (VT)] were measured with a pneumotachometer. Inspired minute ventilation (VI) and mean inspiratory flow (VT/TI) declined exponentially after the cessation of CB stimulation, with first-order time constants of 28.6 +/- 6.7 and 24.6 +/- 1.6 (SD) s, respectively. The slow decay of VI was due primarily to potentiation of both TI and TE, although the effect on the latter predominated. Additional experiments in six subjects showed that brief intense CB stimulation with four to five breaths of N2 during mild exercise induced STP of similar magnitude to that observed in the hypoxic exercise experiments. Finally, the imposition of hyperoxia during air breathing exercise at a level of respiratory drive similar to that induced by the hypoxic exercise did not change VI significantly.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1757326

  10. Periodic breathing in healthy humans at exercise in hypoxia.

    PubMed

    Hermand, Eric; Pichon, Aurélien; Lhuissier, François J; Richalet, Jean-Paul

    2015-01-01

    Periodic breathing is frequent in heart failure or ventilatory disorders during sleep, and common during sleep at high altitude, but has been rarely studied in wakefulness and during exercise. A retrospective analysis of ventilation from hypoxia exercise tests was realized in 82 healthy subjects separated into two groups with either high or low ventilatory response to hypoxia at exercise (HVRe). A fast Fourier transform spectral analysis of the breath-by-breath ventilation (V̇e) signal, O2 saturation, and end-tidal PCO2 evidenced a periodic pattern with a period of 11.1 to 12.0 s. The peak power of the V̇e spectrum was higher in the high HVRe group (P < 0.001). A prospective study (25 subjects) was performed to evaluate the influence of cardiorespiratory factors on the amplitude and period of oscillations in various conditions of exercise (20 to 40% maximal aerobic power) and hypoxia (0 to 4,000 m altitude). The period of V̇e was shorter at exercise (vs. rest, P < 0.001) and hypoxia (vs. normoxia, P < 0.001), and inversely related with cardiac output and V̇e (P < 0.001). V̇e peak power was higher at exercise (P < 0.001) and hypoxia (P < 0.001), and was positively related with cardiac output and V̇e (P < 0.001). V̇e peak power in hypoxia was positively related with the ventilatory response to CO2 (HCVR). This novel observation suggests that healthy subjects demonstrate a spontaneous periodic breathing, not clearly observable at rest and in normoxia, but triggered by hypoxic exercise. The periodic pattern is enhanced in subjects with high HVRe and high HCVR, suggesting that oxygen and CO2 play synergistic roles in the modulation of these oscillations.

  11. Dead space in the breathing apparatus; interaction with ventilation.

    PubMed

    Warkander, D E; Lundgren, C E

    1995-09-01

    Dead space in breathing apparatus may cause increased ventilation and/or CO2 retention. Interactions between ventilation and dead space were tested in the breathing apparatus of three divers: a full face mask with an oro-nasal cup (AGA), a full face mask without an oro-nasal cup (EXO-26) but designed to minimize dead space, and one mouthpiece. Experiments were performed at three depths; 0, 30 and 45 m seawater (msw). The breathing gas was air except at 30 msw where it was 36 O2 in N2. Five certified SCUBA divers were exercised at three levels (0, 50 and 100 W). Ventilation and gas exchange were measured. The dead space in the AGA mask was not influenced by either depth or exercise (mean 0.201). The mean dead space of the EXO-26 was 0.341, but it increased with exercise (p < 0.001) and decreased with depth (p < 0.03). Since the dead space can vary with ventilation levels it is not sufficient to test breathing apparatus only at rest as is required by the US National Institute of Occupational Safety and Health. The mean ventilation with the EXO-26 was higher than with the AGA by 10% at 50 W (p < 0.05) and by 12% (p < 0.01) at 100 W. The same comparison for end-tidal CO2 showed mean increase by 0.30 kPa at the 100-W workload (P < 0.05); changes at other workloads were not statistically significant. Comparisons of the mean inspired PCO2 to the maximum values considered acceptable by various organizations showed that the mouthpiece was always acceptable, the AGA mask was marginally acceptable or better, while sometimes the EXO-26 was not acceptable.

  12. Estimation of tidal ventilation in preterm and term newborn infants using electromagnetic inductance plethysmography.

    PubMed

    Williams, E M; Pickerd, N; Eriksen, M; Øygarden, K; Kotecha, S

    2011-11-01

    Tidal volume (VT) measurements in newborn infants remain largely a research tool. Tidal ventilation and breathing pattern were measured using a new device, FloRight, which uses electromagnetic inductive plethysmography,and compared simultaneously with pneumotachography in 43 infants either receiving no respiratory support or continuous positive airway pressure (CPAP).Twenty-three infants were receiving CPAP (gestational age 28 ± 2 weeks, mean ± SD) and 20 were breathing spontaneously (gestational age 34 ± 4 weeks). The two methods were in reasonable agreement, with VT (r2 = 0.69) ranging from 5 to 23 ml (4–11 ml kg−1) with a mean difference of 0.4 ml and limit of agreement of −4.7 to + 5.5 ml. For respiratory rate, minute ventilation,peak flow and breathing pattern indices, the mean difference between the two methods ranged between 0.7% and 5.8%. The facemask increased the respiratory rate (P < 0.001) in both groups with the change in VT being more pronounced in the infants receiving no respiratory support. Thus, FloRight provides an easy to use technique to measure term and preterm infants in the clinical environment without altering the infant's breathing pattern.

  13. Correlated Variability in the Breathing Pattern and End-Expiratory Lung Volumes in Conscious Humans

    PubMed Central

    Dellaca, Raffaele L.; Aliverti, Andrea; Lo Mauro, Antonella; Lutchen, Kenneth R.; Pedotti, Antonio; Suki, Bela

    2015-01-01

    In order to characterize the variability and correlation properties of spontaneous breathing in humans, the breathing pattern of 16 seated healthy subjects was studied during 40 min of quiet breathing using opto-electronic plethysmography, a contactless technology that measures total and compartmental chest wall volumes without interfering with the subjects breathing. From these signals, tidal volume (VT), respiratory time (TTOT) and the other breathing pattern parameters were computed breath-by-breath together with the end-expiratory total and compartmental (pulmonary rib cage and abdomen) chest wall volume changes. The correlation properties of these variables were quantified by detrended fluctuation analysis, computing the scaling exponentα. VT, TTOT and the other breathing pattern variables showed α values between 0.60 (for minute ventilation) to 0.71 (for respiratory rate), all significantly lower than the ones obtained for end-expiratory volumes, that ranged between 1.05 (for rib cage) and 1.13 (for abdomen) with no significant differences between compartments. The much stronger long-range correlations of the end expiratory volumes were interpreted by a neuromechanical network model consisting of five neuron groups in the brain respiratory center coupled with the mechanical properties of the respiratory system modeled as a simple Kelvin body. The model-based α for VT is 0.57, similar to the experimental data. While the α for TTOT was slightly lower than the experimental values, the model correctly predicted α for end-expiratory lung volumes (1.045). In conclusion, we propose that the correlations in the timing and amplitude of the physiological variables originate from the brain with the exception of end-expiratory lung volume, which shows the strongest correlations largely due to the contribution of the viscoelastic properties of the tissues. This cycle-by-cycle variability may have a significant impact on the functioning of adherent cells in the

  14. Time and volume dependence of dead space in healthy and surfactant-depleted rat lungs during spontaneous breathing and mechanical ventilation.

    PubMed

    Dassow, Constanze; Schwenninger, David; Runck, Hanna; Guttmann, Josef

    2013-11-01

    Volumetric capnography is a standard method to determine pulmonary dead space. Hereby, measured carbon dioxide (CO2) in exhaled gas volume is analyzed using the single-breath diagram for CO2. Unfortunately, most existing CO2 sensors do not work with the low tidal volumes found in small animals. Therefore, in this study, we developed a new mainstream capnograph designed for the utilization in small animals like rats. The sensor was used for determination of dead space volume in healthy and surfactant-depleted rats (n = 62) during spontaneous breathing (SB) and mechanical ventilation (MV) at three different tidal volumes: 5, 8, and 11 ml/kg. Absolute dead space and wasted ventilation (dead space volume in relation to tidal volume) were determined over a period of 1 h. Dead space increase and reversibility of the increase was investigated during MV with different tidal volumes and during SB. During SB, the dead space volume was 0.21 ± 0.14 ml and increased significantly at MV to 0.39 ± 0.03 ml at a tidal volume of 5 ml/kg and to 0.6 ± 0.08 ml at a tidal volume of 8 and 11 ml/kg. Dead space and wasted ventilation during MV increased with tidal volume. This increase was mostly reversible by switching back to SB. Surfactant depletion had no further influence on the dead space increase during MV, but impaired the reversibility of the dead space increase.

  15. Time and volume dependence of dead space in healthy and surfactant-depleted rat lungs during spontaneous breathing and mechanical ventilation.

    PubMed

    Dassow, Constanze; Schwenninger, David; Runck, Hanna; Guttmann, Josef

    2013-11-01

    Volumetric capnography is a standard method to determine pulmonary dead space. Hereby, measured carbon dioxide (CO2) in exhaled gas volume is analyzed using the single-breath diagram for CO2. Unfortunately, most existing CO2 sensors do not work with the low tidal volumes found in small animals. Therefore, in this study, we developed a new mainstream capnograph designed for the utilization in small animals like rats. The sensor was used for determination of dead space volume in healthy and surfactant-depleted rats (n = 62) during spontaneous breathing (SB) and mechanical ventilation (MV) at three different tidal volumes: 5, 8, and 11 ml/kg. Absolute dead space and wasted ventilation (dead space volume in relation to tidal volume) were determined over a period of 1 h. Dead space increase and reversibility of the increase was investigated during MV with different tidal volumes and during SB. During SB, the dead space volume was 0.21 ± 0.14 ml and increased significantly at MV to 0.39 ± 0.03 ml at a tidal volume of 5 ml/kg and to 0.6 ± 0.08 ml at a tidal volume of 8 and 11 ml/kg. Dead space and wasted ventilation during MV increased with tidal volume. This increase was mostly reversible by switching back to SB. Surfactant depletion had no further influence on the dead space increase during MV, but impaired the reversibility of the dead space increase. PMID:23950167

  16. A Study of the Effects of Breath Management Instruction on the Breathing Mode, Knowledge of Breathing, and Performance Skills of College-Level Brass Players.

    ERIC Educational Resources Information Center

    Phillips, Kenneth H.; Sehmann, Karin Harfst

    1990-01-01

    Investigates the effectiveness of breathing instruction on the breath management, performance, and knowledge of breathing among college-level brass musicians. Finds that breathing instruction significantly improved the breath management and knowledge of the breathing for the experimental groups and the musical range of the trombone players in the…

  17. Tidal disruption event demographics

    NASA Astrophysics Data System (ADS)

    Kochanek, C. S.

    2016-09-01

    We survey the properties of stars destroyed in tidal disruption events (TDEs) as a function of black hole (BH) mass, stellar mass and evolutionary state, star formation history and redshift. For M_{BH} ≲ 10^7 M_{⊙}, the typical TDE is due to a M* ˜ 0.3 M⊙ M-dwarf, although the mass function is relatively flat for M_{ast } ≲ M_{⊙}. The contribution from older main-sequence stars and sub-giants is small but not negligible. From MBH ≃ 107.5-108.5 M⊙, the balance rapidly shifts to higher mass stars and a larger contribution from evolved stars, and is ultimately dominated by evolved stars at higher BH masses. The star formation history has little effect until the rates are dominated by evolved stars. TDE rates should decline very rapidly towards higher redshifts. The volumetric rate of TDEs is very high because the BH mass function diverges for low masses. However, any emission mechanism which is largely Eddington-limited for low BH masses suppresses this divergence in any observed sample and leads to TDE samples dominated by MBH ≃ 106.0-107.5 M⊙ BHs with roughly Eddington peak accretion rates. The typical fall-back time is relatively long, with 16 per cent having tfb < 10-1 yr (37 d), and 84 per cent having longer time-scales. Many residual rate discrepancies can be explained if surveys are biased against TDEs with these longer tfb, which seems very plausible if tfb has any relation to the transient rise time. For almost any BH mass function, systematic searches for fainter, faster time-scale TDEs in smaller galaxies, and longer time-scale TDEs in more massive galaxies are likely to be rewarded.

  18. Tidal Boundary Conditions in SEAWAT

    USGS Publications Warehouse

    Mulligan, Ann E.; Langevin, Christian; Post, Vincent E.A.

    2011-01-01

    SEAWAT, a U.S. Geological Survey groundwater flow and transport code, is increasingly used to model the effects of tidal motion on coastal aquifers. Different options are available to simulate tidal boundaries but no guidelines exist nor have comparisons been made to identify the most effective approach. We test seven methods to simulate a sloping beach and a tidal flat. The ocean is represented in one of the three ways: directly using a high hydraulic conductivity (high-K) zone and indirect simulation via specified head boundaries using either the General Head Boundary (GHB) or the new Periodic Boundary Condition (PBC) package. All beach models simulate similar water fluxes across the upland boundary and across the sediment-water interface although the ratio of intertidal to subtidal flow is different at low tide. Simulating a seepage face results in larger intertidal fluxes and influences near-shore heads and salinity. Major differences in flow occur in the tidal flat simulations. Because SEAWAT does not simulate unsaturated flow the water table only rises via flow through the saturated zone. This results in delayed propagation of the rising tidal signal inland. Inundation of the tidal flat is delayed as is flow into the aquifer across the flat. This is severe in the high-K and PBC models but mild in the GHB models. Results indicate that any of the tidal boundary options are fine if the ocean-aquifer interface is steep. However, as the slope of that interface decreases, the high-K and PBC approaches perform poorly and the GHB boundary is preferable.

  19. Tidal boundary conditions in SEAWAT.

    PubMed

    Mulligan, Ann E; Langevin, Christian; Post, Vincent E A

    2011-01-01

    SEAWAT, a U.S. Geological Survey groundwater flow and transport code, is increasingly used to model the effects of tidal motion on coastal aquifers. Different options are available to simulate tidal boundaries but no guidelines exist nor have comparisons been made to identify the most effective approach. We test seven methods to simulate a sloping beach and a tidal flat. The ocean is represented in one of the three ways: directly using a high hydraulic conductivity (high-K) zone and indirect simulation via specified head boundaries using either the General Head Boundary (GHB) or the new Periodic Boundary Condition (PBC) package. All beach models simulate similar water fluxes across the upland boundary and across the sediment-water interface although the ratio of intertidal to subtidal flow is different at low tide. Simulating a seepage face results in larger intertidal fluxes and influences near-shore heads and salinity. Major differences in flow occur in the tidal flat simulations. Because SEAWAT does not simulate unsaturated flow the water table only rises via flow through the saturated zone. This results in delayed propagation of the rising tidal signal inland. Inundation of the tidal flat is delayed as is flow into the aquifer across the flat. This is severe in the high-K and PBC models but mild in the GHB models. Results indicate that any of the tidal boundary options are fine if the ocean-aquifer interface is steep. However, as the slope of that interface decreases, the high-K and PBC approaches perform poorly and the GHB boundary is preferable.

  20. Tidal dynamics of transiting exoplanets

    NASA Astrophysics Data System (ADS)

    Fabrycky, Daniel C.

    2011-11-01

    Transits give us the mass, radius, and orbital properties of the planet, all of which inform dynamical theories. Two properties of the hot Jupiters suggest they had a dramatic origin via tidal damping from high eccentricity. First, the tidally circularized planets (in the 1-4 day pile-up) lie along a relation or boundary in the mass-period plane. This observation may implicate a tidal damping process regulated by planetary radius inflation and Roche lobe overflow, early in the planets' lives. Second, the host stars of many planets have spins misaligned from the planets' orbits. This observation was not expected a priori from the conventional disk migration theory, and it was a boon for the alternative theories of planet-planet scattering and Kozai cycles, accompanied by tidal friction, which predicted it. Now we are faced with a curious observation that the misalignment angle depends on the stellar temperature. It may mean that the tide raised on the stars realigns them, the final result being the tidal consumption of hot Jupiters.

  1. TIDAL LIMITS TO PLANETARY HABITABILITY

    SciTech Connect

    Barnes, Rory; Jackson, Brian; Greenberg, Richard; Raymond, Sean N.

    2009-07-20

    The habitable zones (HZs) of main-sequence stars have traditionally been defined as the range of orbits that intercept the appropriate amount of stellar flux to permit surface water on a planet. Terrestrial exoplanets discovered to orbit M stars in these zones, which are close-in due to decreased stellar luminosity, may also undergo significant tidal heating. Tidal heating may span a wide range for terrestrial exoplanets and may significantly affect conditions near the surface. For example, if heating rates on an exoplanet are near or greater than that on Io (where tides drive volcanism that resurfaces the planet at least every 1 Myr) and produce similar surface conditions, then the development of life seems unlikely. On the other hand, if the tidal heating rate is less than the minimum to initiate plate tectonics, then CO{sub 2} may not be recycled through subduction, leading to a runaway greenhouse that sterilizes the planet. These two cases represent potential boundaries to habitability and are presented along with the range of the traditional HZ for main-sequence, low-mass stars. We propose a revised HZ that incorporates both stellar insolation and tidal heating. We apply these criteria to GJ 581 d and find that it is in the traditional HZ, but its tidal heating alone may be insufficient for plate tectonics.

  2. Follow your breath: Respiratory interoceptive accuracy in experienced meditators

    PubMed Central

    DAUBENMIER, JENNIFER; SZE, JOCELYN; KERR, CATHERINE E.; KEMENY, MARGARET E.; MEHLING, WOLF

    2014-01-01

    Attention to internal bodily sensations is a core feature of mindfulness meditation. Previous studies have not detected differences in interoceptive accuracy between meditators and nonmeditators on heartbeat detection and perception tasks. We compared differences in respiratory interoceptive accuracy between meditators and nonmeditators in the ability to detect and discriminate respiratory resistive loads and sustain accurate perception of respiratory tidal volume during nondistracted and distracted conditions. Groups did not differ in overall performance on the detection and discrimination tasks; however, meditators were more accurate in discriminating the resistive load with the lowest ceiling effect. Meditators were also more accurate during the nondistracted tracking task at a lag time of 1 s following the breath. Results provide initial support for the notion that meditators have greater respiratory interoceptive accuracy compared to nonmeditators. PMID:23692525

  3. pH in nasal exhaled breath condensate in healthy adults.

    PubMed

    Svensson, Sophie; Hellgren, Johan

    2007-09-01

    This paper describes a new method to assess nasal pH in nasal exhaled breath condensate in adults. The study included 19 healthy, non-smoking, adult volunteers without current upper respiratory disease, COPD or asthma. Expiratory breath condensate (EBC) was collected from the nose and mouth respectively. A Jaeger breath condenser was fitted with a transparent facemask and during oral sampling it was fitted with a mouthpiece. The condensates were bubbled with argon gas for 10 minutes to reduce carbon dioxide and the samples were analysed immediately using a calibrated glass electrode and a portable pH-meter. The mean pH in the nasal EBC was 7.0 +/- 0.5 and in oral EBC 6.9 +/- 0.7 (p = 0.6). The nasal EBC-pH was well in agreement with data from previous studies, which measured pH directly on the nasal mucosa with an electrode. In conclusion, this paper describes a method to measure pH in nasal exhaled breath condensate (EBC) in healthy adults during tidal breathing. The nasal EBC-pH related well to previous data from intranasal pH measurements suggesting that nasal EBC-pH could have a role in monitoring pH alterations in the nasal mucosa such as nasal inflammation.

  4. FEV manoeuvre induced changes in breath VOC compositions: an unconventional view on lung function tests.

    PubMed

    Sukul, Pritam; Schubert, Jochen K; Oertel, Peter; Kamysek, Svend; Taunk, Khushman; Trefz, Phillip; Miekisch, Wolfram

    2016-01-01

    Breath volatile organic compound (VOC) analysis can open a non-invasive window onto pathological and metabolic processes in the body. Decades of clinical breath-gas analysis have revealed that changes in exhaled VOC concentrations are important rather than disease specific biomarkers. As physiological parameters, such as respiratory rate or cardiac output, have profound effects on exhaled VOCs, here we investigated VOC exhalation under respiratory manoeuvres. Breath VOCs were monitored by means of real-time mass-spectrometry during conventional FEV manoeuvres in 50 healthy humans. Simultaneously, we measured respiratory and hemodynamic parameters noninvasively. Tidal volume and minute ventilation increased by 292 and 171% during the manoeuvre. FEV manoeuvre induced substance specific changes in VOC concentrations. pET-CO2 and alveolar isoprene increased by 6 and 21% during maximum exhalation. Then they decreased by 18 and 37% at forced expiration mirroring cardiac output. Acetone concentrations rose by 4.5% despite increasing minute ventilation. Blood-borne furan and dimethyl-sulphide mimicked isoprene profile. Exogenous acetonitrile, sulphides, and most aliphatic and aromatic VOCs changed minimally. Reliable breath tests must avoid forced breathing. As isoprene exhalations mirrored FEV performances, endogenous VOCs might assure quality of lung function tests. Analysis of exhaled VOC concentrations can provide additional information on physiology of respiration and gas exchange. PMID:27311826

  5. FEV manoeuvre induced changes in breath VOC compositions: an unconventional view on lung function tests

    PubMed Central

    Sukul, Pritam; Schubert, Jochen K.; Oertel, Peter; Kamysek, Svend; Taunk, Khushman; Trefz, Phillip; Miekisch, Wolfram

    2016-01-01

    Breath volatile organic compound (VOC) analysis can open a non-invasive window onto pathological and metabolic processes in the body. Decades of clinical breath-gas analysis have revealed that changes in exhaled VOC concentrations are important rather than disease specific biomarkers. As physiological parameters, such as respiratory rate or cardiac output, have profound effects on exhaled VOCs, here we investigated VOC exhalation under respiratory manoeuvres. Breath VOCs were monitored by means of real-time mass-spectrometry during conventional FEV manoeuvres in 50 healthy humans. Simultaneously, we measured respiratory and hemodynamic parameters noninvasively. Tidal volume and minute ventilation increased by 292 and 171% during the manoeuvre. FEV manoeuvre induced substance specific changes in VOC concentrations. pET-CO2 and alveolar isoprene increased by 6 and 21% during maximum exhalation. Then they decreased by 18 and 37% at forced expiration mirroring cardiac output. Acetone concentrations rose by 4.5% despite increasing minute ventilation. Blood-borne furan and dimethyl-sulphide mimicked isoprene profile. Exogenous acetonitrile, sulphides, and most aliphatic and aromatic VOCs changed minimally. Reliable breath tests must avoid forced breathing. As isoprene exhalations mirrored FEV performances, endogenous VOCs might assure quality of lung function tests. Analysis of exhaled VOC concentrations can provide additional information on physiology of respiration and gas exchange. PMID:27311826

  6. FEV manoeuvre induced changes in breath VOC compositions: an unconventional view on lung function tests

    NASA Astrophysics Data System (ADS)

    Sukul, Pritam; Schubert, Jochen K.; Oertel, Peter; Kamysek, Svend; Taunk, Khushman; Trefz, Phillip; Miekisch, Wolfram

    2016-06-01

    Breath volatile organic compound (VOC) analysis can open a non-invasive window onto pathological and metabolic processes in the body. Decades of clinical breath-gas analysis have revealed that changes in exhaled VOC concentrations are important rather than disease specific biomarkers. As physiological parameters, such as respiratory rate or cardiac output, have profound effects on exhaled VOCs, here we investigated VOC exhalation under respiratory manoeuvres. Breath VOCs were monitored by means of real-time mass-spectrometry during conventional FEV manoeuvres in 50 healthy humans. Simultaneously, we measured respiratory and hemodynamic parameters noninvasively. Tidal volume and minute ventilation increased by 292 and 171% during the manoeuvre. FEV manoeuvre induced substance specific changes in VOC concentrations. pET-CO2 and alveolar isoprene increased by 6 and 21% during maximum exhalation. Then they decreased by 18 and 37% at forced expiration mirroring cardiac output. Acetone concentrations rose by 4.5% despite increasing minute ventilation. Blood-borne furan and dimethyl-sulphide mimicked isoprene profile. Exogenous acetonitrile, sulphides, and most aliphatic and aromatic VOCs changed minimally. Reliable breath tests must avoid forced breathing. As isoprene exhalations mirrored FEV performances, endogenous VOCs might assure quality of lung function tests. Analysis of exhaled VOC concentrations can provide additional information on physiology of respiration and gas exchange.

  7. Meandering: fluvial versus tidal. (Invited)

    NASA Astrophysics Data System (ADS)

    Seminara, G.

    2009-12-01

    Tidal meanders (Marani et al, Water Resour Res, 2002) display similarities as well as important differences from fluvial meanders (Seminara, J Fluid Mech, 2006). Like fluvial meanders they have characteristic wavelengths scaling with channel width: this is why the convergent character of tidal channels leads to meander wavelengths decaying landward. Unlike fluvial meanders, the typical curvature spectra of tidal meanders contain even harmonics: hence, meander skewing does non display any distinct correlation with the flow direction and the known Kinoshita curve, which approximates the shape of fluvial meanders, is not appropriate to tidal meanders. Additional constraints are brought up by the spatial gradients of the basic bed profile connected to the finite length of tidal channels at equilibrium. In fact, it has been theoretically established (Schuttelaars and De Swart, Eur J Mech, B/Fluids, 1996, Seminara et al, J Fluid Mech submitted, 2009) and confirmed by controlled laboratory experiments (Tambroni et al., J Geoph Res, 2005) that tidal channels closed at one end and connected at the other end with a tidal sea, evolve towards an equilibrium configuration characterized by a ‘slow’ landward decay of the average flow depth. An equilibrium length of the channel is then determined by the formation of a shoreline. Channel curvature affects the lateral equilibrium topography and gives rise to a pattern of point bars and scour pools resembling that of fluvial channels. With some notable differences, though. In fact, Solari et al (J Fluid Mech, 2001) showed that long sequences of weakly sinuous identical meandering channels subject to a symmetrical tidal forcing develop a symmetrical bar-pool pattern with small symmetrical oscillations during the tidal cycle. However, in the laboratory investigations of Garotta et al. (Proceedings RCEM5,2007) the bar-pool pattern was somehow unexpected. In a first experiment, it was in phase with curvature only in the inner half of

  8. Korea tidal power and beyond

    NASA Astrophysics Data System (ADS)

    Song, W. O.; van Walsum, E.

    A study evaluating the tidal power potential on the west coast of Korea is presented. The tidal power plant concept applied to all sites features prefabricated caissons from which the powerhouse and the sluice sections of the plant are built up. In the screening process, all 13 potential sites were compared on the basis of a single basin and single effect schemes operated to produce the maximum amount of energy. The four sites identified as having potential for development (the inner Asan Bay, the outer Asan Bay, the Incheon Bay, and the Garorim Bay) are economically evaluated. It is noted that harbor development and land reclamation can proceed in conjunction with tidal power development.

  9. Submarines, Spacecraft, and Exhaled Breath

    EPA Science Inventory

    The International Association of Breath Research (IABR) meetings are an eclectic gathering of researchers in the medical, environmental and instrumentation fields; our focus is on human health as assessed by the measurement and interpretation of trace chemicals in human exhaled b...

  10. Pulmonary oedema in breath-hold diving: an unusual presentation and computed tomography findings.

    PubMed

    Gempp, Emmanuel; Sbardella, Fabrice; Cardinale, Mickael; Louge, Pierre

    2013-09-01

    Haemoptysis and pulmonary oedema following deep breath-hold diving have been described in recent years. We describe the case of a 33-year-old healthy military diver who presented symptoms suggestive of pulmonary oedema after two breathhold dives, the first lasting 0.5-1 min and the second 1-2 min, to 6 metres' depth in the sea. The diagnosis was promptly confirmed with chest computed tomography showing bilateral interstitial infiltrates in the upper regions of the lungs. To our knowledge, this is the first report to document pulmonary oedema in this setting of shallow breath-hold diving with atypical radiological presentation. A definite mechanism for this specific distribution of lung injury remains unclear.

  11. Functional analysis and intervention for breath holding.

    PubMed

    Kern, L; Mauk, J E; Marder, T J; Mace, F C

    1995-01-01

    We conducted a functional analysis of breath-holding episodes in a 7-year-old girl with severe mental retardation and Cornelia-de-Lange syndrome. The results showed that breath holding served an operant function, primarily to gain access to attention. The intervention, consisting of extinction, scheduled attention, and use of a picture card communication system, resulted in decreased breath holding.

  12. Tidal disruption of dissipative planetesimals

    NASA Astrophysics Data System (ADS)

    Mizuno, H.; Boss, A. P.

    1985-07-01

    A self-consistent numerical model is developed for the tidal disruption of a solid planetesimal. The planetesimal is treated as a highly viscous, slightly compressible fluid whose disturbed parts are an inviscid, pressureless fluid undergoing distortion and disruption. The distortions were constrained to being symmetrical above and below the equatorial plane. The tidal potential is expanded in terms of Legendre polynomials, which eliminates the center of mass acceleration effects, permitting definition of equations of motion in a noninertial frame. Consideration is given to viscous dissipation and to characteristics of the solid-atmosphere boundary. The model is applied to sample cases in one, two and three dimensions.

  13. Particle size concentration distribution and influences on exhaled breath particles in mechanically ventilated patients.

    PubMed

    Wan, Gwo-Hwa; Wu, Chieh-Liang; Chen, Yi-Fang; Huang, Sheng-Hsiu; Wang, Yu-Ling; Chen, Chun-Wan

    2014-01-01

    Humans produce exhaled breath particles (EBPs) during various breath activities, such as normal breathing, coughing, talking, and sneezing. Airborne transmission risk exists when EBPs have attached pathogens. Until recently, few investigations had evaluated the size and concentration distributions of EBPs from mechanically ventilated patients with different ventilation mode settings. This study thus broke new ground by not only evaluating the size concentration distributions of EBPs in mechanically ventilated patients, but also investigating the relationship between EBP level and positive expiratory end airway pressure (PEEP), tidal volume, and pneumonia. This investigation recruited mechanically ventilated patients, with and without pneumonia, aged 20 years old and above, from the respiratory intensive care unit of a medical center. Concentration distributions of EBPs from mechanically ventilated patients were analyzed with an optical particle analyzer. This study finds that EBP concentrations from mechanically ventilated patients during normal breathing were in the range 0.47-2,554.04 particles/breath (0.001-4.644 particles/mL). EBP concentrations did not differ significantly between the volume control and pressure control modes of the ventilation settings in the mechanically ventilated patients. The patient EBPs were sized below 5 µm, and 80% of them ranged from 0.3 to 1.0 µm. The EBPs concentrations in patients with high PEEP (> 5 cmH₂O) clearly exceeded those in patients with low PEEP (≤ 5 cmH₂O). Additionally, a significant negative association existed between pneumonia duration and EBPs concentration. However, tidal volume was not related to EBPs concentration.

  14. Horses Auto-Recruit Their Lungs by Inspiratory Breath Holding Following Recovery from General Anaesthesia

    PubMed Central

    Mosing, Martina; Waldmann, Andreas D.; MacFarlane, Paul; Iff, Samuel; Auer, Ulrike; Bohm, Stephan H.; Bettschart-Wolfensberger, Regula; Bardell, David

    2016-01-01

    This study evaluated the breathing pattern and distribution of ventilation in horses prior to and following recovery from general anaesthesia using electrical impedance tomography (EIT). Six horses were anaesthetised for 6 hours in dorsal recumbency. Arterial blood gas and EIT measurements were performed 24 hours before (baseline) and 1, 2, 3, 4, 5 and 6 hours after horses stood following anaesthesia. At each time point 4 representative spontaneous breaths were analysed. The percentage of the total breath length during which impedance remained greater than 50% of the maximum inspiratory impedance change (breath holding), the fraction of total tidal ventilation within each of four stacked regions of interest (ROI) (distribution of ventilation) and the filling time and inflation period of seven ROI evenly distributed over the dorso-ventral height of the lungs were calculated. Mixed effects multi-linear regression and linear regression were used and significance was set at p<0.05. All horses demonstrated inspiratory breath holding until 5 hours after standing. No change from baseline was seen for the distribution of ventilation during inspiration. Filling time and inflation period were more rapid and shorter in ventral and slower and longer in most dorsal ROI compared to baseline, respectively. In a mixed effects multi-linear regression, breath holding was significantly correlated with PaCO2 in both the univariate and multivariate regression. Following recovery from anaesthesia, horses showed inspiratory breath holding during which gas redistributed from ventral into dorsal regions of the lungs. This suggests auto-recruitment of lung tissue which would have been dependent and likely atelectic during anaesthesia. PMID:27331910

  15. Separation of factors responsible for change in breathing pattern induced by instrumentation.

    PubMed

    Perez, W; Tobin, M J

    1985-11-01

    Employment of mouthpiece and noseclips (MP + NC) has repeatedly been shown to increase tidal volume (VT), but its effect on respiratory frequency (f) and its subsets is controversial. The mechanisms accounting for this alteration in breathing pattern are poorly understood and may include stimulation of oral or nasal sensory receptors or alteration in the route of breathing. In this study we demonstrated that use of a MP + NC, compared with nonobtrusive measurement with a calibrated respiratory inductive plethysmograph, alters the majority of the volume and time indexes of breathing pattern, with increases in minute ventilation (P less than 0.01), VT (P less than 0.001), inspiratory time (TI, P less than 0.05), expiratory time (TE, P less than 0.05), mean inspiratory flow (P less than 0.05), and mean expiratory flow (P less than 0.05) and a decrease in f(P less than 0.05). Separating the potential mechanisms we found that when the respiratory route was not altered, independent oral stimulation (using an occluded MP) or nasal stimulation (by applying paper clips to the alae nasi) did not change the breathing pattern. In contrast, obligatory oral breathing without additional stimulation of the oral or nasal sensory receptors caused increases in VT (P less than 0.05), TI (P less than 0.05), and TE (P less than 0.01) and a fall in f(P less than 0.05). Heating and humidifying the inspired air did not prevent the alteration in breathing pattern with a MP. Thus change in the respiratory route is the major determinant of the alteration in breathing pattern with a MP + NC.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Evaluation of Fractional Regional Ventilation Using 4D-CT and Effects of Breathing Maneuvers on Ventilation

    SciTech Connect

    Mistry, Nilesh N.; Diwanji, Tejan; Shi, Xiutao; Pokharel, Sabin; Feigenberg, Steven; Scharf, Steven M.; D'Souza, Warren D.

    2013-11-15

    Purpose: Current implementations of methods based on Hounsfield units to evaluate regional lung ventilation do not directly incorporate tissue-based mass changes that occur over the respiratory cycle. To overcome this, we developed a 4-dimensional computed tomography (4D-CT)-based technique to evaluate fractional regional ventilation (FRV) that uses an individualized ratio of tidal volume to end-expiratory lung volume for each voxel. We further evaluated the effect of different breathing maneuvers on regional ventilation. The results from this work will help elucidate the relationship between global and regional lung function. Methods and Materials: Eight patients underwent 3 sets of 4D-CT scans during 1 session using free-breathing, audiovisual guidance, and active breathing control. FRV was estimated using a density-based algorithm with mass correction. Internal validation between global and regional ventilation was performed by use of the imaging data collected during the use of active breathing control. The impact of breathing maneuvers on FRV was evaluated comparing the tidal volume from 3 breathing methods. Results: Internal validation through comparison between the global and regional changes in ventilation revealed a strong linear correlation (slope of 1.01, R{sup 2} of 0.97) between the measured global lung volume and the regional lung volume calculated by use of the “mass corrected” FRV. A linear relationship was established between the tidal volume measured with the automated breathing control system and FRV based on 4D-CT imaging. Consistently larger breathing volumes were observed when coached breathing techniques were used. Conclusions: The technique presented improves density-based evaluation of lung ventilation and establishes a link between global and regional lung ventilation volumes. Furthermore, the results obtained are comparable with those of other techniques of functional evaluation such as spirometry and hyperpolarized-gas magnetic

  17. Drive mechanism for production of simulated human breath

    NASA Technical Reports Server (NTRS)

    Bartlett, R. G.; Hendricks, C. M.; Lambert, J. W.; Morison, W. B.

    1972-01-01

    Simulated breath drive mechanism was developed as subsystem to breathing metabolic simulator. Mechanism reproduces complete range of human breath rate, breath depth, and breath waveform, as well as independently controlled functional residual capacity. Mechanism was found capable of simulating various individual human breathing characteristics without any changes of parts.

  18. Correlation of regional breath sound with regional ventilation in emphysema

    SciTech Connect

    Ploysongsang, Y.; Pare, J.A.; Macklem, P.T.

    1982-09-01

    We measured regional breath sound intensities (Ib) by a microphone amplifier system in 8 subjects with emphysema. We also measured regional white noise transmissions (Tn) from the same areas in all subjects. The recorded areas were 5, 10, 15, and 20 cm from the apex of the lung just lateral to the right anterior midclavicular line. Xenon ventilation indexes (xenon tidal raw counts, an index of total regional ventilation; xenon equilibration raw counts, an index of ventilating lung volume; xenon ventilation per unit volume (Vr), an index of ventilation per unit volume) were also recorded from the same areas. The Ib, Tn, Ib/Tn (an index of sound generation), and xenon ventilation indexes were all expressed as a fraction of the mean value of all four recorded areas. The Ib and Ib/Tn correlated best with the xenon tidal raw counts, correlated well with the xenon equilibration raw counts, and correlated poorly with Vr. We conclude that Ib and Ib/Tn can be used to quantify regional ventilation in subjects with emphysema.

  19. Influence of drive and timing mechanisms on breathing pattern and ventilation during mental task performance.

    PubMed

    Wientjes, C J; Grossman, P; Gaillard, A W

    1998-09-01

    Assessment of multiple respiratory measures may provide insight into how behavioral demands affect the breathing pattern. This is illustrated by data from a study among 44 subjects, in which tidal volume, respiration rate, minute ventilation and indices of central drive and timing mechanisms were assessed via inductive plethysmography, in addition to end-tidal PCO2. After a baseline, three conditions of a memory comparison task were presented. The first two conditions differed only with regard to the presence or absence of feedback of performance (NFB and FB). In the third 'all-or-nothing' (AON) condition, subjects only received a monetary bonus, if their performance exceeded that of the previous two conditions. Minute ventilation increased from baseline to all task conditions, and from NFB and FB to AON. Respiration rate increased in all task conditions, but there were no differences between task conditions. Tidal volume decreased during NFB, but was equal to baseline during FB and AON. Of the respiratory control indices, inspiratory flow rate covaried much more closely with minute ventilation than duty cycle. The task performance induced a minor degree of hyperventilation. The discussion focusses on how behavioral demands affect respiratory control processes to produce alterations in breathing pattern and ventilation.

  20. Breathing responses of unanesthetized man and guinea pigs to increased transrespiratory pressure.

    PubMed

    Gillespie, J R; Bruce, E; Alexander, J; Mead, J

    1979-07-01

    We compared the breathing responses of unanesthetized men and guinea pigs to externally imposed shifts in lung volume produced by steady pressures applied to the body surface while the mouth remained near atmospheric pressure. Lung inflation caused no consistent or significant changes either in frequency or end-tidal CO2 in the three men. In contrast, during lung inflation the guinea pigs breathed at low frequencies and smaller tidal volumes and showed consistent increases in arterial PCO2 lasting up to 10 min. The changes seen immediately on application of pressure, namely apneic periods followed by breathing in which inspiratory duration was shortened while expiratory duration was substantially increased, indicates that conscious guinea pigs have active inflation reflexes. We concluded that the reflex responses rather than mechanical factors probably account for the underventilation in the guinea pigs and that guinea pigs are not nearly as well equipped as is man to defend gas exchange in the face of nonmetabolic shifts in lung volume. PMID:381262

  1. What Makes a Tidal Tail?

    NASA Astrophysics Data System (ADS)

    Rodruck, Michael; Konstantopoulos, I.; Charlton, J. C.

    2014-01-01

    Galaxy interactions are famous for creating some of the most visually stunning scenes in astronomy, particularly in the cases of tidal tails. These chaotic regions are known to house breeding grounds for young stellar clusters, as shown through past imaging and spectroscopic studies, but the underlying material remains a mystery. While we know that gas is easily stripped from the parent galaxies, what about the stars? The presence of an older stellar population is crucial to dynamical simulations of tidal tails, but has not yet been confirmed by observation. We use the twin tidal tails of NGC3256 as a case study for determining the presence of an old, underlying stellar population. Newly acquired ugriz Gemini data allows us to distinguish between young and old stars, while previous HST data pinpoints the locations of these objects. Deep imaging surveys have often been used to detect tidal features, including these ancient relics, but our survey will be the first to measure the colors of such objects. This will lead us to place constraints on the original composition of the material that was ejected from the interacting/merging galaxies, and the star formation history.

  2. Analysis of Exhaled Breath for Disease Detection

    NASA Astrophysics Data System (ADS)

    Amann, Anton; Miekisch, Wolfram; Schubert, Jochen; Buszewski, Bogusław; Ligor, Tomasz; Jezierski, Tadeusz; Pleil, Joachim; Risby, Terence

    2014-06-01

    Breath analysis is a young field of research with great clinical potential. As a result of this interest, researchers have developed new analytical techniques that permit real-time analysis of exhaled breath with breath-to-breath resolution in addition to the conventional central laboratory methods using gas chromatography-mass spectrometry. Breath tests are based on endogenously produced volatiles, metabolites of ingested precursors, metabolites produced by bacteria in the gut or the airways, or volatiles appearing after environmental exposure. The composition of exhaled breath may contain valuable information for patients presenting with asthma, renal and liver diseases, lung cancer, chronic obstructive pulmonary disease, inflammatory lung disease, or metabolic disorders. In addition, oxidative stress status may be monitored via volatile products of lipid peroxidation. Measurement of enzyme activity provides phenotypic information important in personalized medicine, whereas breath measurements provide insight into perturbations of the human exposome and can be interpreted as preclinical signals of adverse outcome pathways.

  3. [Stahl, Leibniz, Hoffmann and breathing].

    PubMed

    Carvallo, Sarah

    2006-01-01

    At the beginning of the XVIII th century, Wilhelm Gottfried Leibniz and Friedrich Hoffmann criticize Georg Ernst Stahl's medical theory. They differenciate between unsound and true reasonings. Namely, they validate Stahl's definition of breath but extracting it from its animist basis and placing it in an epistemology obeying to the principle of sufficient reason and to the mechanical model. The stahlian discovery consists in understanding breath as a calorific ventilation against the ancient conception; the iatromechanists recognize its accuracy, but they try then to transpose it to a mechanical model of ventilation. Using it in a different epistemological context implies that they analyze the idea of discovery "true" in its contents, but "wrong" in its hypothesis. It impels to examine the epistemology of medical knowledge, as science and therapeutics, and in its links with the other scientific theories. Thus, if Leibniz as philosopher and Hoffmann as doctor consider Stahl's animism so important, it is because its discoveries question the fundamental principles of medicine.

  4. Self-contained breathing apparatus

    NASA Technical Reports Server (NTRS)

    Sullivan, J. L.; Giorgini, E. A.; Simmonds, M. R. (Inventor)

    1976-01-01

    A self-contained breathing apparatus with automatic redundant fluid pressure controls and a facemask mounted low pressure whistle alarm is described. The first stage of the system includes pair of pressure regulators connected in parallel with different outlet pressures, both of which reduce the pressure of the stored supply gas to pressures compatible with the second stage breathing demand regulator. A primary regulator in the first stage delivers a low output pressure to the demand regulator. In the event of a failure closed condition of the primary regulator an automatic transfer valve switches on the backup regulator. A warning that the supply pressure has been depleted is also provided by a supply pressure actuated transfer valve which transfers the output of the first stage pressure regulators from the primary to the backup regulator. The alarm is activated in either the failure closed condition or if the supply pressure is reduced to a dangerously low level.

  5. Changes in partial pressures of respiratory gases during submerged voluntary breath hold across odontocetes: is body mass important?

    PubMed

    Noren, S R; Williams, T M; Ramirez, K; Boehm, J; Glenn, M; Cornell, L

    2012-02-01

    Odontocetes have an exceptional range in body mass spanning 10(3) kg across species. Because, size influences oxygen utilization and carbon dioxide production rates in mammals, this lineage likely displays an extraordinary variation in oxygen store management compared to other marine mammal groups. To examine this, we measured changes in the partial pressures of respiratory gases ([Formula: see text], [Formula: see text]), pH, and lactate in the blood during voluntary, quiescent, submerged breath holds in Pacific white-sided dolphins (Lagenorhynchus obliquidens), bottlenose dolphins (Tursiops truncatus), and a killer whale (Orcinus orca) representing a mass range of 96-3,850 kg. These measurements provided an empirical determination of the effect of body size on the variability in blood biochemistry during breath hold and experimentally determined aerobic dive limits (ADL) within one taxonomic group (odontocetes). For the species in this study, maximum voluntary breath-hold duration was positively correlated with body mass, ranging from 3.5 min in white-sided dolphins to 13.3 min for the killer whale. Variation in breath-hold duration was associated with differences in the rate of change for [Formula: see text] throughout breath hold; [Formula: see text] decreased twice as fast for the two smaller species (-0.6 mmHg O(2) min(-1)) compared to the largest species (-0.3 mmHg O(2) min(-1)). In contrast, the rate of increase in [Formula: see text] during breath hold was similar across species. These results demonstrate that large body size in odontocetes facilitates increased aerobic breath-hold capacity as mediated by decreased mass-specific metabolic rates (rates of change in [Formula: see text] served as a proxy for oxygen utilization). Indeed the experimentally determined 5 min ADL for bottlenose dolphins was surpassed by the 13.3 min maximum breath hold of the killer whale, which did not end in a rise in lactate. Rather, breath hold ended voluntarily as respiratory

  6. Reconstruction of 4D-CT data sets acquired during free breathing for the analysis of respiratory motion

    NASA Astrophysics Data System (ADS)

    Ehrhardt, Jan; Werner, Rene; Frenzel, Thorsten; Säring, Dennis; Lu, Wei; Low, Daniel; Handels, Heinz

    2006-03-01

    Respiratory motion is a significant source of error in radiotherapy treatment planning. 4D-CT data sets can be useful to measure the impact of organ motion caused by breathing. But modern CT scanners can only scan a limited region of the body simultaneously and patients have to be scanned in segments consisting of multiple slices. For studying free breathing motion multislice CT scans can be collected simultaneously with digital spirometry over several breathing cycles. The 4D data set is assembled by sorting the free breathing multislice CT scans according to the couch position and the tidal volume. But artifacts can occur because there are no data segments for exactly the same tidal volume and all couch positions. We present an optical flow based method for the reconstruction of 4D-CT data sets from multislice CT scans, which are collected simultaneously with digital spirometry. The optical flow between the scans is estimated by a non-linear registration method. The calculated velocity field is used to reconstruct a 4D-CT data set by interpolating data at user-defined tidal volumes. By this technique, artifacts can be reduced significantly. The reconstructed 4D-CT data sets are used for studying inner organ motion during the respiratory cycle. The procedures described were applied to reconstruct 4D-CT data sets for four tumour patients who have been scanned during free breathing. The reconstructed 4D data sets were used to quantify organ displacements and to visualize the abdominothoracic organ motion.

  7. Running and Breathing in Mammals

    NASA Astrophysics Data System (ADS)

    Bramble, Dennis M.; Carrier, David R.

    1983-01-01

    Mechanical constraints appear to require that locomotion and breathing be synchronized in running mammals. Phase locking of limb and respiratory frequency has now been recorded during treadmill running in jackrabbits and during locomotion on solid ground in dogs, horses, and humans. Quadrupedal species normally synchronize the locomotor and respiratory cycles at a constant ratio of 1:1 (strides per breath) in both the trot and gallop. Human runners differ from quadrupeds in that while running they employ several phase-locked patterns (4:1, 3:1, 2:1, 1:1, 5:2, and 3:2), although a 2:1 coupling ratio appears to be favored. Even though the evolution of bipedal gait has reduced the mechanical constraints on respiration in man, thereby permitting greater flexibility in breathing pattern, it has seemingly not eliminated the need for the synchronization of respiration and body motion during sustained running. Flying birds have independently achieved phase-locked locomotor and respiratory cycles. This hints that strict locomotor-respiratory coupling may be a vital factor in the sustained aerobic exercise of endothermic vertebrates, especially those in which the stresses of locomotion tend to deform the thoracic complex.

  8. Maine Tidal Power Initiative: Environmental Impact Protocols For Tidal Power

    SciTech Connect

    Peterson, Michael Leroy; Zydlewski, Gayle Barbin; Xue, Huijie; Johnson, Teresa R.

    2014-02-02

    The Maine Tidal Power Initiative (MTPI), an interdisciplinary group of engineers, biologists, oceanographers, and social scientists, has been conducting research to evaluate tidal energy resources and better understand the potential effects and impacts of marine hydro-kinetic (MHK) development on the environment and local community. Project efforts include: 1) resource assessment, 2) development of initial device design parameters using scale model tests, 3) baseline environmental studies and monitoring, and 4) human and community responses. This work included in-situ measurement of the environmental and social response to the pre-commercial Turbine Generator Unit (TGU®) developed by Ocean Renewable Power Company (ORPC) as well as considering the path forward for smaller community scale projects.

  9. Modeling airway resistance dynamics after tidal and deep inspirations.

    PubMed

    Thorpe, C William; Salome, Cheryl M; Berend, Norbert; King, Gregory G

    2004-11-01

    Using the forced oscillation technique, we tracked airway resistance continuously during quiet breathing (QB) and deep inspiration (DI), thus observing fluctuations in resistance that may reflect mechanisms of airway stretch and renarrowing. After DI, however, the resistance may be depressed for a period not related to volume changes. We hypothesized that this gradual increase in resistance after DI-induced dilation was determined by a simple time constant. Furthermore, to the extent that this effect reflects dynamic characteristics of airway renarrowing, the resistance change after each tidal inspiration should also be constrained by this temporal limit. A model relating resistance fluctuations to the breathing pattern, including both instantaneous and delayed effects, was developed and applied to data from 14 nonasthmatic and 17 asthmatic subjects (forced expiratory volume in 1 s = 103 +/- 13 and 83 +/- 12%, respectively, means +/- SD) after methacholine challenge (dose 145 +/- 80 and 3.0 +/- 3.4 micromol, respectively) that resulted in respective forced expiratory volume in 1 s reductions of 16 +/- 7 and 24 +/- 6% from baseline. Resistance was measured continuously for 1 min of QB, a DI, followed by a further minute of QB. Resistance values at end expiration (Ree) and end inspiration were calculated. We found that the sequence of Ree after DI was best modeled by a power-law function of time rather than an exponential decay (r2 = 0.82 +/- 0.18 compared with 0.63 +/- 0.16; P < 0.01). Furthermore, the coefficient characterizing this "renarrowing function" was close to equal to the coefficient characterizing the equivalent function of resistance change between each resistance value at end inpiration and subsequent Ree during QB, particularly in the nonasthmatic subjects for whom the intraclass correlation was 0.66. This suggests that the same time-dependent factors determine renarrowing after both large and small breaths.

  10. Simulating hydrodynamics on tidal mudflats

    NASA Astrophysics Data System (ADS)

    Cook, S.; Lippmann, T. C.

    2014-12-01

    Biogeochemical cycling in estuaries is governed by fluxes from both riverine sources and through estuarine sediment deposits. Although estimates from river sources are relatively common and easily sampled, estimates of nutrient fluxes through the fluid-sediment interface are less common and limited to deeper portions of the bays away from intertidal areas. Lack of quantifiable shear stress estimates over intertidal areas limits our overall understanding of nutrient budgets in estuaries. Unfortunately, observation of intertidal hydrodynamics and nutrient fluxes over tidal flats and near the water's edge is difficult owing to the temporally varying and spatially extensive region where the tides inundate, and thus numerical modeling is often employed. In this work, the Regional Ocean Modeling System (ROMS), a three dimensional numerical hydrodynamic model was used to investigate the shear stresses over intertidal mudflats in the Great Bay, a tidally-dominated New England estuary cut by several tidal channels and with over 50% of the estuary exposed at low tide. The ROMS wetting and drying scheme was used to simulate the rising and falling tide on the flats, a successful approach adapted in other regions of the world but not always inclusive of tidal channels. Bathymetric data obtained in 2009 and 2013 was used to define the model grid. Predicted tides are forced at Adam's Pt., a natural constriction in the estuary about 20 km upstream of the mouth and at the entrance to the Great Bay. Of particular interest are fluxes of material on-to and off-of the tidal flats which contribute to water quality conditions in the estuary, and are largely governed by shear stresses that drive nutrient fluxes at the fluid-sediment interface. Basin wide estimates of near-bottom shear stresses can be used to estimate first order nutrient fluxes over a tidal cycle and hence describe general biogeochemical dynamics of the estuary. Future work will include enhanced forcing of currents by

  11. State-dependent control of breathing by the retrotrapezoid nucleus

    PubMed Central

    Burke, Peter GR; Kanbar, Roy; Basting, Tyler M; Hodges, Walter M; Viar, Kenneth E; Stornetta, Ruth L; Guyenet, Patrice G

    2015-01-01

    Key points This study explores the state dependence of the hypercapnic ventilatory reflex (HCVR). We simulated an instantaneous increase or decrease of central chemoreceptor activity by activating or inhibiting the retrotrapezoid nucleus (RTN) by optogenetics in conscious rats. During quiet wake or non-REM sleep, hypercapnia increased both breathing frequency (fR) and tidal volume (VT) whereas, in REM sleep, hypercapnia increased VT exclusively. Optogenetic inhibition of RTN reduced VT in all sleep–wake states, but reduced fR only during quiet wake and non-REM sleep. RTN stimulation always increased VT but raised fR only in quiet wake and non-REM sleep. Phasic RTN stimulation produced active expiration and reduced early expiratory airflow (i.e. increased upper airway resistance) only during wake. We conclude that the HCVR is highly state-dependent. The HCVR is reduced during REM sleep because fR is no longer under chemoreceptor control and thus could explain why central sleep apnoea is less frequent in REM sleep. Abstract Breathing has different characteristics during quiet wake, non-REM or REM sleep, including variable dependence on . We investigated whether the retrotrapezoid nucleus (RTN), a proton-sensitive structure that mediates a large portion of the hypercapnic ventilatory reflex, regulates breathing differently during sleep vs. wake. Electroencephalogram, neck electromyogram, blood pressure, respiratory frequency (fR) and tidal volume (VT) were recorded in 28 conscious adult male Sprague–Dawley rats. Optogenetic stimulation of RTN with channelrhodopsin-2, or inhibition with archaerhodopsin, simulated an instantaneous increase or decrease of central chemoreceptor activity. Both opsins were delivered with PRSX8-promoter-containing lentiviral vectors. RTN and catecholaminergic neurons were transduced. During quiet wake or non-REM sleep, hypercapnia (3 or 6% ) increased both fR and VT whereas, in REM sleep, hypercapnia increased VT exclusively. RTN

  12. Prediction of CBS tidal evolution

    NASA Astrophysics Data System (ADS)

    Dryomova, G. N.

    The time series of basic processes, accompanying the tidal evolution of star components of Close Binary Systems (CBS) are predicted in the framework of evolutionary stellar models by Claret (2004). The series includes the apsidal motion period, timescale of synchronization of axial rotation of a star with the orbital revolution, the orbit circularization timescale, and the age. Data from the catalogues by Svechnikov & Perevozkina (1999) and by Torres, Andersen, Gimenez (2010) are used for testing the sensitivity of the numerical prediction algorithm.

  13. Dynamical modeling of tidal streams

    SciTech Connect

    Bovy, Jo

    2014-11-01

    I present a new framework for modeling the dynamics of tidal streams. The framework consists of simple models for the initial action-angle distribution of tidal debris, which can be straightforwardly evolved forward in time. Taking advantage of the essentially one-dimensional nature of tidal streams, the transformation to position-velocity coordinates can be linearized and interpolated near a small number of points along the stream, thus allowing for efficient computations of a stream's properties in observable quantities. I illustrate how to calculate the stream's average location (its 'track') in different coordinate systems, how to quickly estimate the dispersion around its track, and how to draw mock stream data. As a generative model, this framework allows one to compute the full probability distribution function and marginalize over or condition it on certain phase-space dimensions as well as convolve it with observational uncertainties. This will be instrumental in proper data analysis of stream data. In addition to providing a computationally efficient practical tool for modeling the dynamics of tidal streams, the action-angle nature of the framework helps elucidate how the observed width of the stream relates to the velocity dispersion or mass of the progenitor, and how the progenitors of 'orphan' streams could be located. The practical usefulness of the proposed framework crucially depends on the ability to calculate action-angle variables for any orbit in any gravitational potential. A novel method for calculating actions, frequencies, and angles in any static potential using a single orbit integration is described in the Appendix.

  14. Tidally-Induced Thermonuclear Supernovae

    SciTech Connect

    Rosswog, S.; Ramirez-Ruiz, E.; Hix, William Raphael

    2009-01-01

    We discuss the results of 3D simulations of tidal disruptions of white dwarfs by moderate-mass black holes as they may exist in the cores of globular clusters or dwarf galaxies. Our simulations follow self-consistently the hydrodynamic and nuclear evolution from the initial parabolic orbit over the disruption to the build-up of an accretion disk around the black hole. For strong enough encounters (pericentre distances smaller than about 1/3 of the tidal radius) the tidal compression is reversed by a shock and finally results in a thermonuclear explosion. These explosions are not restricted to progenitor masses close to the Chandrasekhar limit, we find exploding examples throughout the whole white dwarf mass range. There is, however, a restriction on the masses of the involved black holes: black holes more massive than 2x105M{circle_dot} swallow a typical 0.6M{circle_dot} white dwarf before their tidal forces can overwhelm the star's selfgravity. Therefore, this mechanism is characteristic for black holes of moderate masses. The material that remains bound to the black hole settles into an accretion disk and produces an Xray flare close to the Eddington limit of L{sub Edd} {approx} 10{sup 41}erg/s (Mbh/1000M{circle_dot}), typically lasting for a few months. The combination of a peculiar thermonuclear supernova together with an X-ray flare thus whistle-blows the existence of such moderate-mass black holes. The next generation of wide field space-based instruments should be able to detect such events.

  15. Dynamical Modeling of Tidal Streams

    NASA Astrophysics Data System (ADS)

    Bovy, Jo

    2014-11-01

    I present a new framework for modeling the dynamics of tidal streams. The framework consists of simple models for the initial action-angle distribution of tidal debris, which can be straightforwardly evolved forward in time. Taking advantage of the essentially one-dimensional nature of tidal streams, the transformation to position-velocity coordinates can be linearized and interpolated near a small number of points along the stream, thus allowing for efficient computations of a stream's properties in observable quantities. I illustrate how to calculate the stream's average location (its "track") in different coordinate systems, how to quickly estimate the dispersion around its track, and how to draw mock stream data. As a generative model, this framework allows one to compute the full probability distribution function and marginalize over or condition it on certain phase-space dimensions as well as convolve it with observational uncertainties. This will be instrumental in proper data analysis of stream data. In addition to providing a computationally efficient practical tool for modeling the dynamics of tidal streams, the action-angle nature of the framework helps elucidate how the observed width of the stream relates to the velocity dispersion or mass of the progenitor, and how the progenitors of "orphan" streams could be located. The practical usefulness of the proposed framework crucially depends on the ability to calculate action-angle variables for any orbit in any gravitational potential. A novel method for calculating actions, frequencies, and angles in any static potential using a single orbit integration is described in the Appendix.

  16. Breath-to-breath variations of alveolar Po2 and Pco2 at barometric pressures of 490, 745 and 1500 Toor in resting awake dogs.

    PubMed

    Imbert, G; Hildwein, G; Dejours, P

    1976-11-01

    Two awake, resting dogs born and raised at low altitude were studied, breathing air (1) at 745 torr, (2) during a 12 days sojourn at 490 torr in an altitude chamber, and (3) during 5 days sojourn at 1500 torr in a hyperbaric chamber. The respired gas was continuously sampled an end-tidal PCO2 and PO2 of sequences of thirty breaths were measured by fast analyzers. The mean value of alveolar PCO2 was 29 torr at high altitude; 35 torr at 745 torr; and 40 torr in hyperbary. The changes of PCO2 indicate different alveolar ventilations which result mainly from the changes of the chemoreceptor drive which is enhanced at high altitude and decreased in hyperbary. The scattering of PCO2 is about the same at the three pressures. The scattering of PO2 is less at high altitude than at sea level, and less at sea level than in hyperbary. On a PCO2 vs PO2 diagram end-tidal PCO2 and PO2 points form elliptical clouds whose mean slopes decrease with the increase of total pressure. The characteristics of the dispersion of the alveolar pressures and of the slopes of the alveolar clouds depend on several factors among which the relevant steepness (i.e. capacitance) of the O2 and CO2 blood abosrption curves at the three pressures presumably plays the major role.

  17. Effect of tracheostomy tube on work of breathing: Comparison of pre- and post-decannulation

    PubMed Central

    Villalba, Darío; Feld, Viviana; Leiva, Valeria; Scrigna, Mariana; Distéfano, Eduardo; Pratto, Romina; Rodriguez, Matías; Collins, Jesica; Rocco, Ana; Matesa, Amelia; Rossi, Damián; Areas, Laura; Virgilio, Sacha; Golfarini, Nicolás; Gil-Rosetti, Gregorio; Diaz-Ballve, Pablo; Planells, Fernando

    2016-01-01

    Objective: To describe and compare the work of breathing (WOB) during spontaneous breathing under four conditions: (1) breathing through a tracheostomy tube with an inflated cuff, (2) breathing through the upper airway (UA) with a deflated cuff and occluded tube, (3) breathing through the UA with an occluded cuffless tube, and (4) postdecannulation. Patients and Methods: Patients who tolerated an occluded cuffless tube were included. Ventilatory variables and esophageal pressure were recorded. The pressure-time product (PTP), PTP/min, and PTP/min/tidal volume (PTP/min/VT) were measured. Each condition was measured for 5 min with a 15 min time interval between evaluations. Quantitative data are expressed as mean ± standard deviation. Single-factor analysis of variance was used, and the Games-Howell test was used for post hoc analysis of comparisons between group means (P ≤ 0.05). Results: Eight patients were studied under each of the four conditions described above. Statistically significant differences were found for PTP, PTP/min, and PTP/min/VT. In the post hoc analysis for PTP, significant differences among all conditions were found. For PTP/min, there was no significant difference between Conditions 2 and 4 (P = 0.138), and for PTP/min/VT, there was no significant difference between Conditions 1 and 2 (P = 0.072) or between Conditions 2 and 3 (P = 0.106). A trend toward a higher PTP, PTP/min, and PTP/min/VT was observed when breathing through a cuffless tracheostomy tube. Conclusion: The four conditions differed with respect to WOB. Cuff inflation could result in a reduced WOB because there is less dead space. Cuffless tracheostomy tubes generate increased WOB, perhaps due to the material deformity caused by body temperature. PMID:27722109

  18. Human Breath Gas Analysis in the Screening of Gestational Diabetes Mellitus

    PubMed Central

    Halbritter, Susanne; Fedrigo, Mattia; Höllriegl, Vera; Szymczak, Wilfried; Maier, Joerg M.; Hummel, Michael

    2012-01-01

    Abstract Background We present a pilot study on the feasibility of the application and advantages of online, noninvasive breath gas analysis (BGA) by proton transfer reaction quadrupole mass spectrometry for the screening of gestational diabetes mellitus (GDM) in 52 pregnant women by means of an oral glucose tolerance test (OGTT). Subjects and Methods We collected and identified samples of end-tidal breath gas from patients during OGTT. Time evolution parameters of challenge-responsive volatile organic compounds (VOCs) in human breath gas were estimated. Multivariate analysis of variance and permutation analysis were used to assess feasibility of BGA as a diagnostic tool for GDM. Results Standard OGTT diagnosis identified pregnant women as having GDM (n=8), impaired glucose tolerance (n=12), and normal glucose tolerance (n=32); a part of this latter group was further subdivided into a “marginal” group (n=9) because of a marginal high 1-h or 2-h OGTT value. We observed that OGTT diagnosis (four metabolic groups) could be mapped into breath gas data. The time evolution of oxidation products of glucose and lipids, acetone metabolites, and thiols in breath gas after a glucose challenge was correlated with GDM diagnosis (P=0.035). Furthermore, basal (fasting) values of dimethyl sulfide and values of methanol in breath gas were inversely correlated with phenotype characteristics such as homeostasis model assessment of insulin resistance index (R=−0.538; P=0.0002, Pcorrected=0.0034) and pregestational body mass index (R=−0.433; P=0.0013, Pcorrected=0.022). Conclusions Noninvasive BGA in challenge response studies was successfully applied to GDM diagnosis and offered an insight into metabolic pathways involved. We propose a new approach to the identification of diagnosis thresholds for GDM screening. PMID:22775148

  19. ARRAY OPTIMIZATION FOR TIDAL ENERGY EXTRACTION IN A TIDAL CHANNEL – A NUMERICAL MODELING ANALYSIS

    SciTech Connect

    Yang, Zhaoqing; Wang, Taiping; Copping, Andrea

    2014-04-18

    This paper presents an application of a hydrodynamic model to simulate tidal energy extraction in a tidal dominated estuary in the Pacific Northwest coast. A series of numerical experiments were carried out to simulate tidal energy extraction with different turbine array configurations, including location, spacing and array size. Preliminary model results suggest that array optimization for tidal energy extraction in a real-world site is a very complex process that requires consideration of multiple factors. Numerical models can be used effectively to assist turbine siting and array arrangement in a tidal turbine farm for tidal energy extraction.

  20. Repetitive transcranial magnetic stimulation over the supplementary motor area modifies breathing pattern in response to inspiratory loading in normal humans

    PubMed Central

    Nierat, Marie-Cécile; Hudson, Anna L.; Chaskalovic, Joël; Similowski, Thomas; Laviolette, Louis

    2015-01-01

    In awake humans, breathing depends on automatic brainstem pattern generators. It is also heavily influenced by cortical networks. For example, functional magnetic resonance imaging and electroencephalographic data show that the supplementary motor area becomes active when breathing is made difficult by inspiratory mechanical loads like resistances or threshold valves, which is associated with perceived respiratory discomfort. We hypothesized that manipulating the excitability of the supplementary motor area with repetitive transcranial magnetic stimulation would modify the breathing pattern response to an experimental inspiratory load and possibly respiratory discomfort. Seven subjects (three men, age 25 ± 4) were studied. Breathing pattern and respiratory discomfort during inspiratory loading were described before and after conditioning the supplementary motor area with repetitive stimulation, using an excitatory paradigm (5 Hz stimulation), an inhibitory paradigm, or sham stimulation. No significant change in breathing pattern during loading was observed after sham conditioning. Excitatory conditioning shortened inspiratory time (p = 0.001), decreased tidal volume (p = 0.016), and decreased ventilation (p = 0.003), as corroborated by an increased end-tidal expired carbon dioxide (p = 0.013). Inhibitory conditioning did not affect ventilation, but lengthened expiratory time (p = 0.031). Respiratory discomfort was mild under baseline conditions, and unchanged after conditioning of the supplementary motor area. This is the first study to show that repetitive transcranial magnetic stimulation conditioning of the cerebral cortex can alter breathing pattern. A 5 Hz conditioning protocol, known to enhance corticophrenic excitability, can reduce the amount of hyperventilation induced by inspiratory threshold loading. Further studies are needed to determine whether and under what circumstances rTMS can have an effect on dyspnoea. PMID:26483701

  1. Tidal Locking Of The Earth

    NASA Astrophysics Data System (ADS)

    Koohafkan, Michael

    2006-05-01

    The Moon's orbit and spin period are nearly synchronized, or tidally locked. Could the Moon's orbit and the Earth's spin eventually synchronize as well? The Moon's gravitational pull on the Earth produces tides in our oceans, and tidal friction gradually lengthens our days. Less obvious gravitational interactions between the Earth and Moon may also have effects on Earth's spin. The Earth is slightly distorted into an egg-like shape, and the torque exerted by the Moon on our equatorial bulge slowly changes the tilt of our spin axis. How do effects such as these change as the Moon drifts away from Earth? I will examine gravitational interactions between Earth and Moon to learn how they contribute to the deceleration of the Earth's rotation. My goal is to determine the amount of time it would take for the Earth's rotational speed to decelerate until the period of a single rotation matches the period of the Moon's orbit around Earth -- when the Earth is ``tidally locked'' with the Moon. I aim to derive a general mathematical expression for the rotational deceleration of the Earth due to Moon's gravitational influences.

  2. North American tidal power prospects

    NASA Astrophysics Data System (ADS)

    Wayne, W. W., Jr.

    1981-07-01

    Prospects for North American tidal power electrical generation are reviewed. Studies by the US Army Corps of Engineers of 90 possible generation schemes in Cobscook Bay, ME, indicated that maximum power generation rather than dependable capacity was the most economic method. Construction cost estimates for 15 MW bulb units in a single effect mode from basin to the sea are provided; five projects were considered ranging from 110-160 MW. Additional tidal power installations are examined for: Half-Moon Cove, ME (12 MW, 18 ft tide); Cook Inlet, AK, which is shown to pose severe environmental and engineering problems due to fish migration, earthquake hazards, and 300 ft deep silt deposits; and the Bay of Fundy, Canada. This last has a 17.8 MW plant under construction in a 29 ft maximum tide area. Other tidal projects of the Maritime Provinces are reviewed, and it is noted that previous economic evaluations based on an oil price of $16/barrel are in need of revision.

  3. Workshop on Stellar Tidal Disruption

    NASA Astrophysics Data System (ADS)

    Farrar, Glennys R.

    2012-04-01

    The past year has seen major advances in the observational status of Stellar Tidal Disruption, with the discovery of two strong optical candidates in archived SDSS data and the real-time X-ray detection of Swift J1644+57, plus rapid radio and optical follow-up establishing it as a probable Tidal Disruption Flare (TDF) in ``blazar mode''. These observations motivated a workshop devoted to discussion of such events and of the theory of their emission and flare rate. Observational contributions included a presentation of Swift J2058+05 (a possible second example of a TDF in blazar mode), reports on the late-time evolution and X-ray variability of the two Swift events, and a proposal that additional candidates may be evidenced by spectral signatures in SDSS. Theory presentations included models of radio emission, theory of light curves and the proposal that GRB101225A may be the Galactic tidal disruption of a neutron star, an interpretation of Swift J1644+57 as due to the disruption of a white dwarf instead of main-sequence star, calculation of the dependence of the TDF rate on the spin of the black hole, and analysis of the SDSS events, fitting their SEDs to profiles of thoretical emission from accretion disks and showing that their luminosity and rate are consistent with the proposal that TDEs can be responsible for UHECR acceleration.

  4. Breath Tests to Assess Alcoholic Liver Disease.

    PubMed

    Furnari, Manuele; Ahmed, Iftikhar; Erpecum, Karel J van; Savarino, Vincenzo; Giannini, Edoardo G

    2016-01-01

    The prevalence of Alcohol related Liver Disease (ALD) continues to rise all over the world due to changing drinking behaviour of the population. Liver disease due to excessive alcohol consumption causes significant morbidity and mortality, and poses a substantial economic burden to the health care resources. Early diagnosis and treatment of ALD may help prevent progression to cirrhosis and hepatocellular carcinoma. The last decade has seen a rising interest in potential use of non-invasive tests in clinical practice, including diagnosis and monitoring of chronic liver diseases. Over the past few decades, breath testing has been investigated extensively in the diagnosis of ALD, and has shown promising results in predicting the early stages of ALD. A variety of breath tests have been utilised in this regard including the13Clabelled breath tests, aminopyrine breath test , galactose breath test , methacetin breath test, and keto-isocaproic acid breath test. These tests have demonstrated good results in identification of both significant and severe liver disease among patients with ALD. Volatile Organic Compounds (VOC) are chemicals, which can be quantified in breath and other biological fluids, and represent physio-pathological activities within an individual. Alteration in the pattern of breath VOCs can be correlated with a number of diseases including ALD. Early stages of ALD can be detected using these breath tests, which can lead to adoption of preventive measures to reduce the progression of liver disease. This review focuses on the clinical utility of current and future breath tests, including breath VOC, as a non-invasive means of predicting early stages of ALD. PMID:27515960

  5. Graph-based retrospective 4D image construction from free-breathing MRI slice acquisitions

    NASA Astrophysics Data System (ADS)

    Tong, Yubing; Udupa, Jayaram K.; Ciesielski, Krzysztof C.; McDonough, Joseph M.; Mong, Andrew; Campbell, Robert M.

    2014-03-01

    4D or dynamic imaging of the thorax has many potential applications [1, 2]. CT and MRI offer sufficient speed to acquire motion information via 4D imaging. However they have different constraints and requirements. For both modalities both prospective and retrospective respiratory gating and tracking techniques have been developed [3, 4]. For pediatric imaging, x-ray radiation becomes a primary concern and MRI remains as the de facto choice. The pediatric subjects we deal with often suffer from extreme malformations of their chest wall, diaphragm, and/or spine, as such patient cooperation needed by some of the gating and tracking techniques are difficult to realize without causing patient discomfort. Moreover, we are interested in the mechanical function of their thorax in its natural form in tidal breathing. Therefore free-breathing MRI acquisition is the ideal modality of imaging for these patients. In our set up, for each coronal (or sagittal) slice position, slice images are acquired at a rate of about 200-300 ms/slice over several natural breathing cycles. This produces typically several thousands of slices which contain both the anatomic and dynamic information. However, it is not trivial to form a consistent and well defined 4D volume from these data. In this paper, we present a novel graph-based combinatorial optimization solution for constructing the best possible 4D scene from such data entirely in the digital domain. Our proposed method is purely image-based and does not need breath holding or any external surrogates or instruments to record respiratory motion or tidal volume. Both adult and children patients' data are used to illustrate the performance of the proposed method. Experimental results show that the reconstructed 4D scenes are smooth and consistent spatially and temporally, agreeing with known shape and motion of the lungs.

  6. Qigong--Chinese breathing exercise.

    PubMed

    Koh, T C

    1982-01-01

    Qigong is an ancient Chinese breathing exercise with meditation which is being developed today for therapy of chronic illnesses in the People's Republic of China. It is claimed to cure gastric ulcers, hypertension, anxiety neurosis, otitis media, cancer and has even been used as a form of anaesthesia. Although the physiological effects produced by Qigong resemble those of meditation, there are certain features that are unique and often mysterious. Research in the future may prove Qigong to be a useful adjunct in the practice of medicine.

  7. Breathing

    MedlinePlus Videos and Cool Tools

    ... size of the thoracic cavity and decreases the pressure inside. As a result, air rushes in and ... volume of the thoracic cavity decreases, while the pressure within it increases. As a result, the lungs ...

  8. Shoulder and hip roll differences between breathing and non-breathing conditions in front crawl swimming.

    PubMed

    Psycharakis, Stelios G; McCabe, Carla

    2011-06-01

    The effects of breathing on body roll have been previously investigated for the roll of the whole trunk only. The purposes of this study were: to calculate separately the shoulder roll (SR) and hip roll (HR) of swimmers during front crawl for non-breathing and preferred-side breathing conditions; to assess the differences in the magnitude and temporal characteristics of these variables between non-breathing and preferred-side breathing conditions; and to examine their association with swimming performance (indicated by swimming speed). Twelve male swimmers who competed at national and international level performed two maximum 25 m front crawl trials: one non-breathing and one with breathing to their preferred side. Performance was recorded with four below and two above water synchronised cameras. SR and HR in both trials were calculated for the breathing and non-breathing sides. The timings of SR and HR peaks to each side and at the positions of neutral roll were also calculated. Swimming speed was significantly slower in the breathing trial (p < 0.01). Swimmers rolled their shoulders and hips to the breathing side significantly more in the breathing than in the non-breathing trial (SR: p < 0.01; HR: p = 0.03). Nevertheless, there were no significant differences in the overall SR or HR between these trials. In the breathing trial, SR was higher in the breathing than in the non-breathing side (p < 0.01) but HR was not significantly different (p = 0.07). There was no evidence to suggest that temporal characteristics of SR or HR were associated with swimming performance.

  9. TIDAL FRICTION AND TIDAL LAGGING. APPLICABILITY LIMITATIONS OF A POPULAR FORMULA FOR THE TIDAL TORQUE

    SciTech Connect

    Efroimsky, Michael; Makarov, Valeri V. E-mail: vvm@usno.navy.mil

    2013-02-10

    Tidal torques play a key role in rotational dynamics of celestial bodies. They govern these bodies' tidal despinning and also participate in the subtle process of entrapment of these bodies into spin-orbit resonances. This makes tidal torques directly relevant to the studies of habitability of planets and their moons. Our work begins with an explanation of how friction and lagging should be built into the theory of bodily tides. Although much of this material can be found in various publications, a short but self-consistent summary on the topic has been lacking in the hitherto literature, and we are filling the gap. After these preparations, we address a popular concise formula for the tidal torque, which is often used in the literature, for planets or stars. We explain why the derivation of this expression, offered in the paper by Goldreich and in the books by Kaula (Equation (4.5.29)) and Murray and Dermott (Equation (4.159)), implicitly sets the time lag to be frequency independent. Accordingly, the ensuing expression for the torque can be applied only to bodies having a very special (and very hypothetical) rheology which makes the time lag frequency independent, i.e., the same for all Fourier modes in the spectrum of tide. This expression for the torque should not be used for bodies of other rheologies. Specifically, the expression cannot be combined with an extra assertion of the geometric lag being constant, because at finite eccentricities the said assumption is incompatible with the constant-time-lag condition.

  10. Tidal Friction and Tidal Lagging. Applicability Limitations of a Popular Formula for the Tidal Torque

    NASA Astrophysics Data System (ADS)

    Efroimsky, Michael; Makarov, Valeri V.

    2013-02-01

    Tidal torques play a key role in rotational dynamics of celestial bodies. They govern these bodies' tidal despinning and also participate in the subtle process of entrapment of these bodies into spin-orbit resonances. This makes tidal torques directly relevant to the studies of habitability of planets and their moons. Our work begins with an explanation of how friction and lagging should be built into the theory of bodily tides. Although much of this material can be found in various publications, a short but self-consistent summary on the topic has been lacking in the hitherto literature, and we are filling the gap. After these preparations, we address a popular concise formula for the tidal torque, which is often used in the literature, for planets or stars. We explain why the derivation of this expression, offered in the paper by Goldreich and in the books by Kaula (Equation (4.5.29)) and Murray & Dermott (Equation (4.159)), implicitly sets the time lag to be frequency independent. Accordingly, the ensuing expression for the torque can be applied only to bodies having a very special (and very hypothetical) rheology which makes the time lag frequency independent, i.e., the same for all Fourier modes in the spectrum of tide. This expression for the torque should not be used for bodies of other rheologies. Specifically, the expression cannot be combined with an extra assertion of the geometric lag being constant, because at finite eccentricities the said assumption is incompatible with the constant-time-lag condition.

  11. Experimental studies on artificial ventilation using a tidal volume ventilator. Mechanics and dynamics of ventilation.

    PubMed

    Lindahl, S; Okmian, L

    1979-08-01

    In 24 piglets (2.7-24.5 kg b.w.), the mechanics of ventilation, the accuracy of dosage of respiratory volumes, and the influence of the ventilator's volume/pressure characteristics (Cvent, "internal compliance") on the dynamic course of insufflation were studied. A linear relationship was shown to exist between tidal volume and end-inspiratory tracheal pressure and between tidal volume and insufflation time. The insufflation time was reduced to about 50% of previously registered values. The error between set and registered tidal volume was found to be 6.0 +/- 2.7%. During the insufflation a linear relationship was found between the instant amount of delivered breathing gas and the corresponding endotracheal pressure change. The ventilator's Cvent did (and body size, total compliance and tidal volume did not) significantly influence the size of the direction coefficient for the linear instantaneous volume/pressure relationship, the magnitude of tracheal peak pressure and a short insufflation time, and vice versa. The use of greater power from the ventilator resulted in a significant shortening of the duration of insufflation and vice versa. The duration of insufflation is the parameter of choice in evaluating the efficiency of the ventilatory equipment. When the ventilator's performance is defined, measurements of the duration of insufflation may enable evaluation of conditions within the lungs.

  12. News from the Breath Analysis Summit 2011.

    PubMed

    Corradi, Massimo; Mutti, Antonio

    2012-05-23

    This special section highlights some of the important work presented at the Breath Analysis Summit 2011, which was held in Parma (Italy) from 11 to 14 September 2011. The meeting, which was jointly organized by the International Association for Breath Research and the University of Parma, was attended by more than 250 delegates from 33 countries, and offered 34 invited lectures and 64 unsolicited scientific contributions. The summit was organized to provide a forum to scientists, engineers and clinicians to present their latest findings and to meet industry executives and entrepreneurs to discuss key trends, future directions and technologies available for breath analysis. A major focus was on nitric oxide, exhaled breath condensate, electronic nose, mass spectrometry and newer sensor technologies. Medical applications ranged from asthma and other respiratory diseases to gastrointestinal disease, occupational diseases, critical care and cancer. Most people identify breath tests with breathalysers used by police to estimate ethanol concentration in blood. However, breath testing has far more sophisticated applications. Breath analysis is rapidly evolving as a new frontier in medical testing for disease states in the lung and beyond. Every individual has a breath fingerprint-or 'breathprint'-that can provide useful information about his or her state of health. This breathprint comprises the many thousands of molecules that are expelled with each breath we exhale. Breath research in the past few years has uncovered the scientific and molecular basis for such clinical observations. Relying on mass spectrometry, we have been able to identify many such unique substances in exhaled breath, including gases, such as nitric oxide (NO) and carbon monoxide (CO), and a wide array of volatile organic compounds. Exhaled breath also carries aerosolized droplets that can be collected as an exhaled breath condensate that contains endogenously produced non-volatile compounds. Breath

  13. 42 CFR 84.81 - Compressed breathing gas and liquefied breathing gas containers; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from American National Standards... 42 Public Health 1 2013-10-01 2013-10-01 false Compressed breathing gas and liquefied breathing... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.81 Compressed...

  14. 42 CFR 84.81 - Compressed breathing gas and liquefied breathing gas containers; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from American National Standards... 42 Public Health 1 2012-10-01 2012-10-01 false Compressed breathing gas and liquefied breathing... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.81 Compressed...

  15. 42 CFR 84.81 - Compressed breathing gas and liquefied breathing gas containers; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from American National Standards... 42 Public Health 1 2014-10-01 2014-10-01 false Compressed breathing gas and liquefied breathing... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.81 Compressed...

  16. Tidal acceleration of black holes and superradiance

    NASA Astrophysics Data System (ADS)

    Cardoso, Vitor; Pani, Paolo

    2013-02-01

    Tidal effects have long ago locked the Moon in a synchronous rotation with the Earth and progressively increase the Earth-Moon distance. This ‘tidal acceleration’ hinges on dissipation. Binaries containing black holes may also be tidally accelerated, dissipation being caused by the event horizon—a flexible, viscous one-way membrane. In fact, this process is known for many years under a different guise: superradiance. Here, we provide compelling evidence for a strong connection between tidal acceleration and superradiant scattering around spinning black holes. In general relativity, tidal acceleration is obscured by the gravitational-wave emission. However, when coupling to light scalar degrees of freedom is allowed, an induced dipole moment produces a ‘polarization acceleration’, which might be orders of magnitude stronger than tidal quadrupolar effects. Consequences for optical and gravitational-wave observations are intriguing and it is not impossible that imprints of such a mechanism have already been observed.

  17. Gravitoelectromagnetic analogy based on tidal tensors

    SciTech Connect

    Costa, L. Filipe O.; Herdeiro, Carlos A. R.

    2008-07-15

    We propose a new approach to a physical analogy between general relativity and electromagnetism, based on tidal tensors of both theories. Using this approach we write a covariant form for the gravitational analogues of the Maxwell equations, which makes transparent both the similarities and key differences between the two interactions. The following realizations of the analogy are given. The first one matches linearized gravitational tidal tensors to exact electromagnetic tidal tensors in Minkowski spacetime. The second one matches exact magnetic gravitational tidal tensors for ultrastationary metrics to exact magnetic tidal tensors of electromagnetism in curved spaces. In the third we show that our approach leads to a two-step exact derivation of Papapetrou's equation describing the force exerted on a spinning test particle. Analogous scalar invariants built from tidal tensors of both theories are also discussed.

  18. TIDAL NOVAE IN COMPACT BINARY WHITE DWARFS

    SciTech Connect

    Fuller, Jim; Lai Dong

    2012-09-01

    Compact binary white dwarfs (WDs) undergoing orbital decay due to gravitational radiation can experience significant tidal heating prior to merger. In these WDs, the dominant tidal effect involves the excitation of outgoing gravity waves in the inner stellar envelope and the dissipation of these waves in the outer envelope. As the binary orbit decays, the WDs are synchronized from outside in (with the envelope synchronized first, followed by the core). We examine the deposition of tidal heat in the envelope of a carbon-oxygen WD and study how such tidal heating affects the structure and evolution of the WD. We show that significant tidal heating can occur in the star's degenerate hydrogen layer. This layer heats up faster than it cools, triggering runaway nuclear fusion. Such 'tidal novae' may occur in all WD binaries containing a CO WD, at orbital periods between 5 minutes and 20 minutes, and precede the final merger by 10{sup 5}-10{sup 6} years.

  19. Protective supplied breathing air garment

    DOEpatents

    Childers, E.L.; Hortenau, E.F. von.

    1984-07-10

    A breathing air garment is disclosed for isolating a wearer from hostile environments containing toxins or irritants includes a suit and a separate head protective enclosure or hood engaging a suit collar in sealing attachment. The hood and suit collar are cylindrically shaped and dimensioned to enable the wearer to withdraw his hands from the suit sleeves to perform manual tasks within the hood interior. Breathing air is supplied from an external air line with an air delivery hose attached to the hood interior. The hose feeds air into an annular halo-like fiber-filled plenum having spaced discharge orifices attached to the hood top wall. A plurality of air exhaust/check valves located at the suit extremities cooperate with the hood air delivery system to provide a cooling flow of circulating air from the hood throughout the suit interior. A suit entry seal provided on the suit rear torso panel permits access into the suit and is sealed with an adhesive sealing flap. 17 figs.

  20. Protective supplied breathing air garment

    DOEpatents

    Childers, Edward L.; von Hortenau, Erik F.

    1984-07-10

    A breathing air garment for isolating a wearer from hostile environments containing toxins or irritants includes a suit and a separate head protective enclosure or hood engaging a suit collar in sealing attachment. The hood and suit collar are cylindrically shaped and dimensioned to enable the wearer to withdraw his hands from the suit sleeves to perform manual tasks within the hood interior. Breathing air is supplied from an external air line with an air delivery hose attached to the hood interior. The hose feeds air into an annular halo-like fiber-filled plenum having spaced discharge orifices attached to the hood top wall. A plurality of air exhaust/check valves located at the suit extremities cooperate with the hood air delivery system to provide a cooling flow of circulating air from the hood throughout the suit interior. A suit entry seal provided on the suit rear torso panel permits access into the suit and is sealed with an adhesive sealing flap.

  1. Calculating lunar retreat rates using tidal rhythmites

    USGS Publications Warehouse

    Kvale, E.P.; Johnson, H.W.; Sonett, C.P.; Archer, A.W.; Zawistoski, A.N.N.

    1999-01-01

    Tidal rhythmites are small-scale sedimenta??r}- structures that can preserve a hierarchy of astronomically induced tidal periods. They can also preserve a record of periodic nontidal sedimentation. If properly interpreted and understood, tidal rhjthmites can be an important component of paleoastronomy and can be used to extract information on ancient lunar orbital dynamics including changes in Earth-Moon distance through geologic time. Herein we present techniques that can be used to calculate ancient Earth-Moon distances. Each of these techniques, when used on a modern high-tide data set, results in calculated estimates of lunar orbital periods and an EarthMoon distance that fall well within 1 percent of the actual values. Comparisons to results from modern tidal data indicate that ancient tidal rhythmite data as short as 4 months can provide suitable estimates of lunar orbital periods if these tidal records are complete. An understanding of basic tidal theory allows for the evaluation of completeness of the ancient tidal record as derived from an analysis of tidal rhythmites. Utilizing the techniques presented herein, it appears from the rock record that lunar orbital retreat slowed sometime during the midPaleozoic. Copyright ??1999, SEPM (Society for Sedimentary Geology).

  2. Tidal friction in close-in planets

    NASA Astrophysics Data System (ADS)

    Rodríguez, Adrián; Ferraz-Mello, Sylvio; Hussmann, Hauke

    2008-05-01

    We use Darwin's theory (Darwin, 1880) to derive the main results on the orbital and rotational evolution of a close-in companion (exoplanet or planetary satellite) due to tidal friction. The given results do not depend on any assumption linking the tidal lags to the frequencies of the corresponding tide harmonics (except that equal frequency harmonics are assumed to span equal lags). Emphasis is given to the study of the synchronization of the planetary rotation in the two possible final states for a non-zero eccentricity : (1) the super-synchronous stationary rotation resulting from the vanishing of the average tidal torque; (2) the capture into a 1:1 spin-orbit resonance (true synchronization), which is only possible if an additional torque exists acting in opposition to the tidal torque. Results are given under the assumption that this additional torque is produced by a non-tidal permanent equatorial asymmetry of the planet. The indirect tidal effects and some non-tidal effects due to that asymmetry are considered. For sake of comparison with other works, the results obtained when tidal lags are assumed proportional to the corresponding tidal wave frequencies are also given.

  3. Submarines, spacecraft and exhaled breath.

    PubMed

    Pleil, Joachim D; Hansel, Armin

    2012-03-01

    Foreword The International Association of Breath Research (IABR) meetings are an eclectic gathering of researchers in the medical, environmental and instrumentation fields; our focus is on human health as assessed by the measurement and interpretation of trace chemicals in human exhaled breath. What may have escaped our notice is a complementary field of research that explores the creation and maintenance of artificial atmospheres practised by the submarine air monitoring and air purification (SAMAP) community. SAMAP is comprised of manufacturers, researchers and medical professionals dealing with the engineering and instrumentation to support human life in submarines and spacecraft (including shuttlecraft and manned rockets, high-altitude aircraft, and the International Space Station (ISS)). Here, the immediate concerns are short-term survival and long-term health in fairly confined environments where one cannot simply 'open the window' for fresh air. As such, one of the main concerns is air monitoring and the main sources of contamination are CO(2) and other constituents of human exhaled breath. Since the inaugural meeting in 1994 in Adelaide, Australia, SAMAP meetings have been held every two or three years alternating between the North American and European continents. The meetings are organized by Dr Wally Mazurek (a member of IABR) of the Defense Systems Technology Organization (DSTO) of Australia, and individual meetings are co-hosted by the navies of the countries in which they are held. An overriding focus at SAMAP is life support (oxygen availability and carbon dioxide removal). Certainly, other air constituents are also important; for example, the closed environment of a submarine or the ISS can build up contaminants from consumer products, cooking, refrigeration, accidental fires, propulsion and atmosphere maintenance. However, the most immediate concern is sustaining human metabolism: removing exhaled CO(2) and replacing metabolized O(2). Another

  4. Submarines, spacecraft and exhaled breath.

    PubMed

    Pleil, Joachim D; Hansel, Armin

    2012-03-01

    Foreword The International Association of Breath Research (IABR) meetings are an eclectic gathering of researchers in the medical, environmental and instrumentation fields; our focus is on human health as assessed by the measurement and interpretation of trace chemicals in human exhaled breath. What may have escaped our notice is a complementary field of research that explores the creation and maintenance of artificial atmospheres practised by the submarine air monitoring and air purification (SAMAP) community. SAMAP is comprised of manufacturers, researchers and medical professionals dealing with the engineering and instrumentation to support human life in submarines and spacecraft (including shuttlecraft and manned rockets, high-altitude aircraft, and the International Space Station (ISS)). Here, the immediate concerns are short-term survival and long-term health in fairly confined environments where one cannot simply 'open the window' for fresh air. As such, one of the main concerns is air monitoring and the main sources of contamination are CO(2) and other constituents of human exhaled breath. Since the inaugural meeting in 1994 in Adelaide, Australia, SAMAP meetings have been held every two or three years alternating between the North American and European continents. The meetings are organized by Dr Wally Mazurek (a member of IABR) of the Defense Systems Technology Organization (DSTO) of Australia, and individual meetings are co-hosted by the navies of the countries in which they are held. An overriding focus at SAMAP is life support (oxygen availability and carbon dioxide removal). Certainly, other air constituents are also important; for example, the closed environment of a submarine or the ISS can build up contaminants from consumer products, cooking, refrigeration, accidental fires, propulsion and atmosphere maintenance. However, the most immediate concern is sustaining human metabolism: removing exhaled CO(2) and replacing metabolized O(2). Another

  5. Work of Breathing into Snow in the Presence versus Absence of an Artificial Air Pocket Affects Hypoxia and Hypercapnia of a Victim Covered with Avalanche Snow: A Randomized Double Blind Crossover Study

    PubMed Central

    2015-01-01

    Presence of an air pocket and its size play an important role in survival of victims buried in the avalanche snow. Even small air pockets facilitate breathing. We hypothesize that the size of the air pocket significantly affects the airflow resistance and work of breathing. The aims of the study are (1) to investigate the effect of the presence of an air pocket on gas exchange and work of breathing in subjects breathing into the simulated avalanche snow and (2) to test whether it is possible to breathe with no air pocket. The prospective interventional double-blinded study involved 12 male volunteers, from which 10 completed the whole protocol. Each volunteer underwent two phases of the experiment in a random order: phase “AP”—breathing into the snow with a one-liter air pocket, and phase “NP”—breathing into the snow with no air pocket. Physiological parameters, fractions of oxygen and carbon dioxide in the airways and work of breathing expressed as pressure-time product were recorded continuously. The main finding of the study is that it is possible to breath in the avalanche snow even with no air pocket (0 L volume), but breathing under this condition is associated with significantly increased work of breathing. The significant differences were initially observed for end-tidal values of the respiratory gases (EtO2 and EtCO2) and peripheral oxygen saturation (SpO2) between AP and NP phases, whereas significant differences in inspiratory fractions occurred much later (for FIO2) or never (for FICO2). The limiting factor in no air pocket conditions is excessive increase in work of breathing that induces increase in metabolism accompanied by higher oxygen consumption and carbon dioxide production. The presence of even a small air pocket reduces significantly the work of breathing. PMID:26666523

  6. Work of Breathing into Snow in the Presence versus Absence of an Artificial Air Pocket Affects Hypoxia and Hypercapnia of a Victim Covered with Avalanche Snow: A Randomized Double Blind Crossover Study.

    PubMed

    Roubík, Karel; Sieger, Ladislav; Sykora, Karel

    2015-01-01

    Presence of an air pocket and its size play an important role in survival of victims buried in the avalanche snow. Even small air pockets facilitate breathing. We hypothesize that the size of the air pocket significantly affects the airflow resistance and work of breathing. The aims of the study are (1) to investigate the effect of the presence of an air pocket on gas exchange and work of breathing in subjects breathing into the simulated avalanche snow and (2) to test whether it is possible to breathe with no air pocket. The prospective interventional double-blinded study involved 12 male volunteers, from which 10 completed the whole protocol. Each volunteer underwent two phases of the experiment in a random order: phase "AP"--breathing into the snow with a one-liter air pocket, and phase "NP"--breathing into the snow with no air pocket. Physiological parameters, fractions of oxygen and carbon dioxide in the airways and work of breathing expressed as pressure-time product were recorded continuously. The main finding of the study is that it is possible to breath in the avalanche snow even with no air pocket (0 L volume), but breathing under this condition is associated with significantly increased work of breathing. The significant differences were initially observed for end-tidal values of the respiratory gases (EtO2 and EtCO2) and peripheral oxygen saturation (SpO2) between AP and NP phases, whereas significant differences in inspiratory fractions occurred much later (for FIO2) or never (for FICO2). The limiting factor in no air pocket conditions is excessive increase in work of breathing that induces increase in metabolism accompanied by higher oxygen consumption and carbon dioxide production. The presence of even a small air pocket reduces significantly the work of breathing.

  7. Work of Breathing into Snow in the Presence versus Absence of an Artificial Air Pocket Affects Hypoxia and Hypercapnia of a Victim Covered with Avalanche Snow: A Randomized Double Blind Crossover Study.

    PubMed

    Roubík, Karel; Sieger, Ladislav; Sykora, Karel

    2015-01-01

    Presence of an air pocket and its size play an important role in survival of victims buried in the avalanche snow. Even small air pockets facilitate breathing. We hypothesize that the size of the air pocket significantly affects the airflow resistance and work of breathing. The aims of the study are (1) to investigate the effect of the presence of an air pocket on gas exchange and work of breathing in subjects breathing into the simulated avalanche snow and (2) to test whether it is possible to breathe with no air pocket. The prospective interventional double-blinded study involved 12 male volunteers, from which 10 completed the whole protocol. Each volunteer underwent two phases of the experiment in a random order: phase "AP"--breathing into the snow with a one-liter air pocket, and phase "NP"--breathing into the snow with no air pocket. Physiological parameters, fractions of oxygen and carbon dioxide in the airways and work of breathing expressed as pressure-time product were recorded continuously. The main finding of the study is that it is possible to breath in the avalanche snow even with no air pocket (0 L volume), but breathing under this condition is associated with significantly increased work of breathing. The significant differences were initially observed for end-tidal values of the respiratory gases (EtO2 and EtCO2) and peripheral oxygen saturation (SpO2) between AP and NP phases, whereas significant differences in inspiratory fractions occurred much later (for FIO2) or never (for FICO2). The limiting factor in no air pocket conditions is excessive increase in work of breathing that induces increase in metabolism accompanied by higher oxygen consumption and carbon dioxide production. The presence of even a small air pocket reduces significantly the work of breathing. PMID:26666523

  8. NASA firefighters breathing system program report

    NASA Technical Reports Server (NTRS)

    Wood, W. B.

    1977-01-01

    Because of the rising incidence of respiratory injury to firefighters, local governments expressed the need for improved breathing apparatus. A review of the NASA firefighters breathing system program, including concept definition, design, development, regulatory agency approval, in-house testing, and program conclusion is presented.

  9. How Does a Hopping Kangaroo Breathe?

    ERIC Educational Resources Information Center

    Giuliodori, Mauricio J.; Lujan, Heidi L.; Janbaih, Hussein; DiCarlo, Stephen E.

    2010-01-01

    We developed a model to demonstrate how a hopping kangaroo breathes. Interestingly, a kangaroo uses less energy to breathe while hopping than while standing still. This occurs, in part, because rather than using muscle power to move air into and out of the lungs, air is pulled into (inspiration) and pushed out of (expiration) the lungs as the…

  10. BREATHING PATTERN DISORDERS AND FUNCTIONAL MOVEMENT

    PubMed Central

    Dr. Esformes, Joseph

    2014-01-01

    Study Design: Experimental design Background: Normal breathing mechanics play a key role in posture and spinal stabilization. Breathing Pattern Disorders (BPD) have been shown to contribute to pain and motor control deficits, which can result in dysfunctional movement patterns. The Functional Movement Screen™ (FMS™) has been shown to accurately predict injury in individuals who demonstrate poor movement patterns. The role BPD play on functional movement is not well established. Furthermore, there is currently no single test to clinically diagnose BPD. A variety of methods are used, but correlations between them are poor. Purpose: To examine the relationship between BPD and functional movement and identify correlations between different measures of BPD. Methods: Breathing was assessed in 34 healthy individuals using a multi‐dimensional approach that included biomechanical, biochemical, breathing related symptoms, and breathing functionality measures. Movement was assessed using the FMS™. Analysis, involving independent t‐tests and Pearson correlation were performed to identify associations between measures. Results: Individuals who exhibited biochemical and biomechanical signs of BPD were significantly more likely to score poorly on the FMS™. These studied measures of BPD correlated highly with each other. Conclusion: These results demonstrate the importance of diaphragmatic breathing on functional movement. Inefficient breathing could result in muscular imbalance, motor control alterations, and physiological adaptations that are capable of modifying movement. These findings provide evidence for improved breathing evaluations by clinicians. Level of Evidence: 2B PMID:24567853

  11. EXHALED BREATH ANALYSIS FOR HUMAN EXPOSURE RESEARCH

    EPA Science Inventory

    Exhaled breath collection and analysis has historically been used in environmental research studies to characterize exposures to volatile organic compounds. The use of this approach is based on the fact that many compounds present in blood are reflected in the breath, and that...

  12. Estimating tidal current amplitudes outside estuaries and characterizing the zone of estuarine tidal influence

    NASA Astrophysics Data System (ADS)

    Whitney, Michael M.; Garvine, Richard W.

    2008-02-01

    Tidal currents within many estuaries are stronger than on the adjacent continental shelf. Estuarine tidal influence extends onto the shelf elevating tidal amplitudes above ambient shelf levels over a region outside the estuary. In this paper, a kinematic theory that describes tidal flow in these estuary-shelf tidal interaction zones is derived and tested. Using these results, tidal current amplitudes outside estuaries are estimated and the range and intensity of estuarine tidal influence is characterized. The estimates for the tidal current amplitudes ( utide) of the dominant constituent are appropriate for linear or weakly nonlinear systems with predominantly barotropic tides; the ratio of tidal height to water depth is small ( η/ h≪1) in linear or weakly nonlinear regimes. Within tidal interaction zones, the tidal current amplitude is composed of an ambient shelf part ( ua) and an estuary-induced part ( ue). The characteristic shelf amplitude far from the estuary is used to set ua. Continuity arguments indicate that ue (averaged over a control volume arc centered on the mouth with radius r and a swath angle of γπ) approximately equals the ratio of the tidal volume flux through the mouth ( Vm) and the cross-sectional area of any control volume arc (u≈V/γπrh¯). This approximation holds where the squared product of the tidal wave number and radial distance is small: ( kr) 2≪1. For a shelf with constant slope α and small coastal wall depth, the arc-averaged depth is h¯≈sr (where s=2 α/ pi for γ=1). For this shelf bathymetry, ue decays with squared radial distance from the estuary mouth. Theoretical predictions are consistent with observed tidal current amplitudes outside the Delaware Bay and Block Island Sound. In both test cases, the estimated and observed amplitudes exhibit an r-2 dependence and decay over a similar distance. The relative importance of estuarine tidal influence is assessed with the tidal interaction index ( Ti= ue/ ua). The

  13. Rapid eye movement sleep in breath holders.

    PubMed

    Kohyama, J; Hasegawa, T; Shimohira, M; Fukumizu, M; Iwakawa, Y

    2000-07-01

    One-night polysomnography was performed on seven subjects suffering from breath-holding spells, including one whose death was suggested to be a consequence of a breath-holding spell. The fatal case showed no rapid eye movements (REMs) during REM sleep, although he exhibited REMs during wakefulness. The average numbers of both REMs and bursts of REMs in REM sleep in the other six breath holders were significantly lower than those in age-matched controls. The breath holders showed no airway obstruction, desaturation, or sleep fragmentation. Since the rapid ocular activity in REM sleep is generated in the brain stem, we hypothesized that a functional brainstem disturbance is involved in the occurrence of breath-holding spells.

  14. Breathing evaluation and retraining in manual therapy.

    PubMed

    McLaughlin, Laurie

    2009-07-01

    Patients with back and neck pain commonly seek body work yet there are some who do not experience full recovery with the typical tool kit of manual therapy, education and exercise, suggesting the need for additional clinical approaches. Epidemiological literature linking back pain with breathing difficulties suggests one possibility. Altered motor control associated with back and neck pain appears to negatively impact breathing mechanics, which may have negative consequences on respiratory chemistry. Changes in respiratory chemistry can have profound effects on body system function. Altered breathing has been recognized for many years as a potential source of a wide variety of unexplained symptoms. There has been controversy around accurate diagnosis with symptoms and questionnaires often being the only methods used. Capnography, which is routinely used in critical care settings, offers an objective measure of respiratory chemistry providing physiological data on which to base a diagnosis of poor breathing. Capnography can also be used as biofeedback to guide breathing retraining.

  15. Computer simulation of breathing systems for divers

    SciTech Connect

    Sexton, P.G.; Nuckols, M.L.

    1983-02-01

    A powerful new tool for the analysis and design of underwater breathing gas systems is being developed. A versatile computer simulator is described which makes possible the modular ''construction'' of any conceivable breathing gas system from computer memory-resident components. The analysis of a typical breathing gas system is demonstrated using this simulation technique, and the effects of system modifications on performance of the breathing system are shown. This modeling technique will ultimately serve as the foundation for a proposed breathing system simulator under development by the Navy. The marriage of this computer modeling technique with an interactive graphics system will provide the designer with an efficient, cost-effective tool for the development of new and improved diving systems.

  16. Slow breathing influences cardiac autonomic responses to postural maneuver: Slow breathing and HRV.

    PubMed

    Vidigal, Giovanna Ana de Paula; Tavares, Bruna S; Garner, David M; Porto, Andrey A; Carlos de Abreu, Luiz; Ferreira, Celso; Valenti, Vitor E

    2016-05-01

    Chronic slow breathing has been reported to improve Heart Rate Variability (HRV) in patients with cardiovascular disorders. However, it is not clear regarding its acute effects on HRV responses on autonomic analysis. We evaluated the acute effects of slow breathing on cardiac autonomic responses to postural change manoeuvre (PCM). The study was conducted on 21 healthy male students aged between 18 and 35 years old. In the control protocol, the volunteer remained at rest seated for 15 min under spontaneous breathing and quickly stood up within 3 s and remained standing for 15 min. In the slow breathing protocol, the volunteer remained at rest seated for 10 min under spontaneous breath, then performed slow breathing for 5 min and rapidly stood up within 3 s and remained standing for 15 min. Slow breathing intensified cardiac autonomic responses to postural maneuver. PMID:27157952

  17. Impact loading and locomotor-respiratory coordination significantly influence breathing dynamics in running humans.

    PubMed

    Daley, Monica A; Bramble, Dennis M; Carrier, David R

    2013-01-01

    Locomotor-respiratory coupling (LRC), phase-locking between breathing and stepping rhythms, occurs in many vertebrates. When quadrupedal mammals gallop, 1∶1 stride per breath coupling is necessitated by pronounced mechanical interactions between locomotion and ventilation. Humans show more flexibility in breathing patterns during locomotion, using LRC ratios of 2∶1, 2.5∶1, 3∶1, or 4∶1 and sometimes no coupling. Previous studies provide conflicting evidence on the mechanical significance of LRC in running humans. Some studies suggest LRC improves breathing efficiency, but others suggest LRC is mechanically insignificant because 'step-driven flows' (ventilatory flows attributable to step-induced forces) contribute a negligible fraction of tidal volume. Yet, although step-driven flows are brief, they cause large fluctuations in ventilatory flow. Here we test the hypothesis that running humans use LRC to minimize antagonistic effects of step-driven flows on breathing. We measured locomotor-ventilatory dynamics in 14 subjects running at a self-selected speed (2.6±0.1 ms(-1)) and compared breathing dynamics in their naturally 'preferred' and 'avoided' entrainment patterns. Step-driven flows occurred at 1-2X step frequency with peak magnitudes of 0.97±0.45 Ls(-1) (mean ±S.D). Step-driven flows varied depending on ventilatory state (high versus low lung volume), suggesting state-dependent changes in compliance and damping of thoraco-abdominal tissues. Subjects naturally preferred LRC patterns that minimized antagonistic interactions and aligned ventilatory transitions with assistive phases of the step. Ventilatory transitions initiated in 'preferred' phases within the step cycle occurred 2x faster than those in 'avoided' phases. We hypothesize that humans coordinate breathing and locomotion to minimize antagonistic loading of respiratory muscles, reduce work of breathing and minimize rate of fatigue. Future work could address the potential consequences of

  18. Impact loading and locomotor-respiratory coordination significantly influence breathing dynamics in running humans.

    PubMed

    Daley, Monica A; Bramble, Dennis M; Carrier, David R

    2013-01-01

    Locomotor-respiratory coupling (LRC), phase-locking between breathing and stepping rhythms, occurs in many vertebrates. When quadrupedal mammals gallop, 1∶1 stride per breath coupling is necessitated by pronounced mechanical interactions between locomotion and ventilation. Humans show more flexibility in breathing patterns during locomotion, using LRC ratios of 2∶1, 2.5∶1, 3∶1, or 4∶1 and sometimes no coupling. Previous studies provide conflicting evidence on the mechanical significance of LRC in running humans. Some studies suggest LRC improves breathing efficiency, but others suggest LRC is mechanically insignificant because 'step-driven flows' (ventilatory flows attributable to step-induced forces) contribute a negligible fraction of tidal volume. Yet, although step-driven flows are brief, they cause large fluctuations in ventilatory flow. Here we test the hypothesis that running humans use LRC to minimize antagonistic effects of step-driven flows on breathing. We measured locomotor-ventilatory dynamics in 14 subjects running at a self-selected speed (2.6±0.1 ms(-1)) and compared breathing dynamics in their naturally 'preferred' and 'avoided' entrainment patterns. Step-driven flows occurred at 1-2X step frequency with peak magnitudes of 0.97±0.45 Ls(-1) (mean ±S.D). Step-driven flows varied depending on ventilatory state (high versus low lung volume), suggesting state-dependent changes in compliance and damping of thoraco-abdominal tissues. Subjects naturally preferred LRC patterns that minimized antagonistic interactions and aligned ventilatory transitions with assistive phases of the step. Ventilatory transitions initiated in 'preferred' phases within the step cycle occurred 2x faster than those in 'avoided' phases. We hypothesize that humans coordinate breathing and locomotion to minimize antagonistic loading of respiratory muscles, reduce work of breathing and minimize rate of fatigue. Future work could address the potential consequences of

  19. Diaphragmatic amplitude and accessory inspiratory muscle activity in nasal and mouth-breathing adults: a cross-sectional study.

    PubMed

    Trevisan, Maria Elaine; Boufleur, Jalusa; Soares, Juliana Corrêa; Haygert, Carlos Jesus Pereira; Ries, Lilian Gerdi Kittel; Corrêa, Eliane Castilhos Rodrigues

    2015-06-01

    The purpose of this study was to evaluate the electromyographic activity of the accessory inspiratory muscles and the diaphragmatic amplitude (DA) in nasal and mouth-breathing adults. The study evaluated 38 mouth-breathing (MB group) and 38 nasal-breathing (NB group) adults, from 18 to 30years old and both sexes. Surface electromyography (sEMG) was used to evaluate the amplitude and symmetry (POC%) of the sternocleidomastoid (SCM) and upper trapezius (UT) muscles at rest, during nasal slow inspiration at Lung Total Capacity (LTC) and, during rapid and abrupt inspiration: Sniff, Peak Nasal Inspiratory Flow (PNIF) and Maximum Inspiratory Pressure (MIP). M-mode ultrasonography assessed the right diaphragm muscle amplitude in three different nasal inspirations: at tidal volume (TV), Sniff and inspiration at LTC. The SCM activity was significantly lower in the MB group during Sniff, PNIF (p<0.01, Mann-Whitney test) and MIP (p<0.01, t-test). The groups did not differ during rest and inspiration at LTC, regarding sEMG amplitude and POC%. DA was significantly lower in the MB group at TV (p<0.01, Mann-Whitney) and TLC (p=0.03, t-test). Mouth breathing reflected on lower recruitment of the accessory inspiratory muscles during fast inspiration and lower diaphragmatic amplitude, compared to nasal breathing.

  20. Breath Testing for Small Intestinal Bacterial Overgrowth: Should We Bother?

    PubMed

    Pimentel, Mark

    2016-03-01

    The hydrogen breath test is based on following breath hydrogen levels after the administration of a carbohydrate (most commonly lactulose) to a patient with suspected small intestinal bacterial overgrowth. The test is based on the interaction between the administered carbohydrate and the intestinal bacteria. The resulting fermentation produces hydrogen. A positive breath test is based on a breath hydrogen rise prior to the expected arrival time in the highly microbial cecum. Despite renewed enthusiasm for breath testing in recent years due to associations with conditions such as irritable bowel syndrome, breath testing poses many challenges. In this argument against breath testing, several pitfalls that complicate breath testing will be described. PMID:26902227

  1. 46 CFR 197.450 - Breathing gas tests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... commencement of diving operations, at the umbilical or underwater breathing apparatus connection point for the... underwater breathing apparatus connection point for the diver, for percentage of oxygen....

  2. Particle concentration in exhaled breath

    SciTech Connect

    Fairchild, C.I.; Stampfer, J.F.

    1987-11-01

    Measurements were made of the number of concentration of particles in exhaled breath under various conditions of exercise. A laser light scattering particle spectrometer was used to count particles exhaled by test subjects wearing respirators in a challenge environment of clean, dry air. Precautions were taken to ensure that particles were not generated by the respirators and that no extraneous water or other particles were produced in the humid exhaled air. The number of particles detected in exhales air varied over a range from <0.10 to approx. 4 particles/cm/sup 3/ depending upon the test subject and his activity. Subjects at rest exhaled the lowest concentration of particles, whereas exercises producing a faster respiration rate caused increased exhalation of particles. Exhaled particle concentration can limit the usefulness of nondiscriminating, ambient challenge aerosols for the fit testing of highly protective respirators.

  3. The indoor air we breathe.

    PubMed Central

    Oliver, L C; Shackleton, B W

    1998-01-01

    Increasingly recognized as a potential public health problem since the outbreak of Legionnaire's disease in Philadelphia in 1976, polluted indoor air has been associated with health problems that include asthma, sick building syndrome, multiple chemical sensitivity, and hypersensitivity pneumonitis. Symptoms are often nonspecific and include headache, eye and throat irritation, chest tightness and shortness of breath, and fatigue. Air-borne contaminants include commonly used chemicals, vehicular exhaust, microbial organisms, fibrous glass particles, and dust. Identified causes include defective building design and construction, aging of buildings and their ventilation systems, poor climate control, inattention to building maintenance. A major contributory factor is the explosion in the use of chemicals in building construction and furnishing materials over the past four decades. Organizational issues and psychological variables often contribute to the problem and hinder its resolution. This article describes the health problems related to poor indoor air quality and offers solutions. Images p398-a p399-a PMID:9769764

  4. The indoor air we breathe.

    PubMed

    Oliver, L C; Shackleton, B W

    1998-01-01

    Increasingly recognized as a potential public health problem since the outbreak of Legionnaire's disease in Philadelphia in 1976, polluted indoor air has been associated with health problems that include asthma, sick building syndrome, multiple chemical sensitivity, and hypersensitivity pneumonitis. Symptoms are often nonspecific and include headache, eye and throat irritation, chest tightness and shortness of breath, and fatigue. Air-borne contaminants include commonly used chemicals, vehicular exhaust, microbial organisms, fibrous glass particles, and dust. Identified causes include defective building design and construction, aging of buildings and their ventilation systems, poor climate control, inattention to building maintenance. A major contributory factor is the explosion in the use of chemicals in building construction and furnishing materials over the past four decades. Organizational issues and psychological variables often contribute to the problem and hinder its resolution. This article describes the health problems related to poor indoor air quality and offers solutions.

  5. Kozai Cycles and Tidal Friction

    SciTech Connect

    L, K; P.P., E

    2009-07-17

    Several studies in the last three years indicate that close binaries, i.e. those with periods of {approx}< 3 d, are very commonly found to have a third body in attendance. We argue that this proves that the third body is necessary in order to make the inner period so short, and further argue that the only reasonable explanation is that the third body causes shrinkage of the inner period, from perhaps a week or more to the current short period, by means of the combination of Kozai cycles and tidal friction (KCTF). In addition, once KCTF has produced a rather close binary, magnetic braking also combined with tidal friction (MBTF) can decrease the inner orbit further, to the formation of a contact binary or even a merged single star. Some of the products of KCTF that have been suggested, either by others or by us, are W UMa binaries, Blue Stragglers, X-ray active BY Dra stars, and short-period Algols. We also argue that some components of wide binaries are actually merged remnants of former close inner pairs. This may include such objects as rapidly rotating dwarfs (AB Dor, BO Mic) and some (but not all) Be stars.

  6. Modified ventilatory response characteristics to exercise in breath-hold divers.

    PubMed

    Roecker, Kai; Metzger, Jule; Scholz, Tobias; Tetzlaff, Kay; Sorichter, Stephan; Walterspacher, Stephan

    2014-09-01

    Specific adjustments to repeated extreme apnea are not fully known and understood. While a blunted ventilatory chemosensitivity to CO2 is described for elite breath-hold divers (BHDs) at rest, it is unclear whether specific adaptations affect their response to dynamic exercise. Eight elite BHDs with a previously validated decrease in CO2 chemosensitivity, 8 scuba divers (SCDs), and 8 matched control subjects were included in a study where markers of ventilatory response, Fowler's dead space, partial pressure of carbon dioxide (pCO2), and blood lactate concentrations during cycle exercise were measured. Maximal power output did not differ between the groups, but lactate threshold (θL) appeared at a significantly lowered respiratory compensation point (RCP) and at a higher VO2 for the BHDs. End-tidal (petCO2) and estimated arterial pCO2 (paCO2) were significantly higher in BHDs at θL, the RCP, and maximum exhaustion. BHDs showed a significantly (P < .01) slower breathing pattern in relation to a given tidal volume at a specific work rate. In summary, BHDs presented signs of a metabolic shift from aerobic to anaerobic energy supply, decreased chemosensitivity during exercise, and a distinct ventilatory-response pattern during cycle exercise that differs from SCDs and controls. PMID:24231513

  7. Modified ventilatory response characteristics to exercise in breath-hold divers.

    PubMed

    Roecker, Kai; Metzger, Jule; Scholz, Tobias; Tetzlaff, Kay; Sorichter, Stephan; Walterspacher, Stephan

    2014-09-01

    Specific adjustments to repeated extreme apnea are not fully known and understood. While a blunted ventilatory chemosensitivity to CO2 is described for elite breath-hold divers (BHDs) at rest, it is unclear whether specific adaptations affect their response to dynamic exercise. Eight elite BHDs with a previously validated decrease in CO2 chemosensitivity, 8 scuba divers (SCDs), and 8 matched control subjects were included in a study where markers of ventilatory response, Fowler's dead space, partial pressure of carbon dioxide (pCO2), and blood lactate concentrations during cycle exercise were measured. Maximal power output did not differ between the groups, but lactate threshold (θL) appeared at a significantly lowered respiratory compensation point (RCP) and at a higher VO2 for the BHDs. End-tidal (petCO2) and estimated arterial pCO2 (paCO2) were significantly higher in BHDs at θL, the RCP, and maximum exhaustion. BHDs showed a significantly (P < .01) slower breathing pattern in relation to a given tidal volume at a specific work rate. In summary, BHDs presented signs of a metabolic shift from aerobic to anaerobic energy supply, decreased chemosensitivity during exercise, and a distinct ventilatory-response pattern during cycle exercise that differs from SCDs and controls.

  8. TIDALLY HEATED TERRESTRIAL EXOPLANETS: VISCOELASTIC RESPONSE MODELS

    SciTech Connect

    Henning, Wade G.; O'Connell, Richard J.; Sasselov, Dimitar D.

    2009-12-20

    Tidal friction in exoplanet systems, driven by orbits that allow for durable nonzero eccentricities at short heliocentric periods, can generate internal heating far in excess of the conditions observed in our own solar system. Secular perturbations or a notional 2:1 resonance between a hot Earth and hot Jupiter can be used as a baseline to consider the thermal evolution of convecting bodies subject to strong viscoelastic tidal heating. We compare results first from simple models using a fixed Quality factor and Love number, and then for three different viscoelastic rheologies: the Maxwell body, the Standard Anelastic Solid (SAS), and the Burgers body. The SAS and Burgers models are shown to alter the potential for extreme tidal heating by introducing the possibility of new equilibria and multiple response peaks. We find that tidal heating tends to exceed radionuclide heating at periods below 10-30 days, and exceed insolation only below 1-2 days. Extreme cases produce enough tidal heat to initiate global-scale partial melting, and an analysis of tidal limiting mechanisms such as advective cooling for earthlike planets is discussed. To explore long-term behaviors, we map equilibria points between convective heat loss and tidal heat input as functions of eccentricity. For the periods and magnitudes discussed, we show that tidal heating, if significant, is generally detrimental to the width of habitable zones.

  9. Tidal deformations of a spinning compact object

    NASA Astrophysics Data System (ADS)

    Pani, Paolo; Gualtieri, Leonardo; Maselli, Andrea; Ferrari, Valeria

    2015-07-01

    The deformability of a compact object induced by a perturbing tidal field is encoded in the tidal Love numbers, which depend sensibly on the object's internal structure. These numbers are known only for static, spherically-symmetric objects. As a first step to compute the tidal Love numbers of a spinning compact star, here we extend powerful perturbative techniques to compute the exterior geometry of a spinning object distorted by an axisymmetric tidal field to second order in the angular momentum. The spin of the object introduces couplings between electric and magnetic deformations and new classes of induced Love numbers emerge. For example, a spinning object immersed in a quadrupolar, electric tidal field can acquire some induced mass, spin, quadrupole, octupole and hexadecapole moments to second order in the spin. The deformations are encoded in a set of inhomogeneous differential equations which, remarkably, can be solved analytically in vacuum. We discuss certain subtleties in defining the tidal Love numbers in general relativity, which are due to the difficulty in separating the tidal field from the linear response of the object in the solution, even in the static case. By extending the standard procedure to identify the linear response in the static case, we prove analytically that the Love numbers of a Kerr black hole remain zero to second order in the spin. As a by-product, we provide the explicit form for a slowly-rotating, tidally-deformed Kerr black hole to quadratic order in the spin, and discuss its geodesic and geometrical properties.

  10. Aerosol deposition characteristics in distal acinar airways under cyclic breathing conditions.

    PubMed

    Ma, Baoshun; Darquenne, Chantal

    2011-05-01

    Although the major mechanisms of aerosol deposition in the lung are known, detailed quantitative data in anatomically realistic models are still lacking, especially in the acinar airways. In this study, an algorithm was developed to build multigenerational three-dimensional models of alveolated airways with arbitrary bifurcation angles and spherical alveolar shape. Using computational fluid dynamics, the deposition of 1- and 3-μm aerosol particles was predicted in models of human alveolar sac and terminal acinar bifurcation under rhythmic wall motion for two breathing conditions (functional residual capacity = 3 liter, tidal volume = 0.5 and 0.9 liter, breathing period = 4 s). Particles entering the model during one inspiration period were tracked for multiple breathing cycles until all particles deposited or escaped from the model. Flow recirculation inside alveoli occurred only during transition between inspiration and expiration and accounted for no more than 1% of the whole cycle. Weak flow irreversibility and convective transport were observed in both models. The average deposition efficiency was similar for both breathing conditions and for both models. Under normal gravity, total deposition was ~33 and 75%, of which ~67 and 96% occurred during the first cycle, for 1- and 3-μm particles, respectively. Under zero gravity, total deposition was ~2-5% for both particle sizes. These results support previous findings that gravitational sedimentation is the dominant deposition mechanism for micrometer-sized aerosols in acinar airways. The results also showed that moving walls and multiple breathing cycles are needed for accurate estimation of aerosol deposition in acinar airways.

  11. Relativistic theory of tidal Love numbers

    SciTech Connect

    Binnington, Taylor; Poisson, Eric

    2009-10-15

    In Newtonian gravitational theory, a tidal Love number relates the mass multipole moment created by tidal forces on a spherical body to the applied tidal field. The Love number is dimensionless, and it encodes information about the body's internal structure. We present a relativistic theory of Love numbers, which applies to compact bodies with strong internal gravities; the theory extends and completes a recent work by Flanagan and Hinderer, which revealed that the tidal Love number of a neutron star can be measured by Earth-based gravitational-wave detectors. We consider a spherical body deformed by an external tidal field, and provide precise and meaningful definitions for electric-type and magnetic-type Love numbers; and these are computed for polytropic equations of state. The theory applies to black holes as well, and we find that the relativistic Love numbers of a nonrotating black hole are all zero.

  12. Time-frequency methods and voluntary ramped-frequency breathing: a powerful combination for exploration of human neurophysiological mechanisms

    PubMed Central

    Stankovski, Tomislav; Cooke, William H.; Rudas, László; Stefanovska, Aneta

    2013-01-01

    We experimentally altered the timing of respiratory motoneuron activity as a means to modulate and better understand otherwise hidden human central neural and hemodynamic oscillatory mechanisms. We recorded the electrocardiogram, finger photoplethysmographic arterial pressure, tidal carbon dioxide concentrations, and muscle sympathetic nerve activity in 13 healthy supine young men who gradually increased or decreased their breathing frequencies between 0.05 and 0.25 Hz over 9-min periods. We analyzed results with traditional time- and frequency-domain methods, and also with time-frequency methods (wavelet transform, wavelet phase coherence, and directional coupling). We determined statistical significance and identified frequency boundaries by comparing measurements with randomly generated surrogates. Our results support several major conclusions. First, respiration causally modulates both sympathetic (weakly) and vagal motoneuron (strongly) oscillations over a wide frequency range—one that extends well below the frequency of actual breaths. Second, breathing frequency broadly modulates vagal baroreflex gain, with peak gains registered in the low frequency range. Third, breathing frequency does not influence median levels of sympathetic or vagal activity over time. Fourth, phase relations between arterial pressure and sympathetic and vagal motoneurons are unaffected by breathing, and are therefore likely secondary to intrinsic responsiveness of these motoneurons to other synaptic inputs. Finally, breathing frequency does not affect phase coherence between diastolic pressure and muscle sympathetic oscillations, but it augments phase coherence between systolic pressure and R-R interval oscillations over a limited portion of the usual breathing frequency range. These results refine understanding of autonomic oscillatory processes and those physiological mechanisms known as the human respiratory gate. PMID:24114700

  13. Take a breath and take the turn: how breathing meets turns in spontaneous dialogue

    PubMed Central

    Rochet-Capellan, Amélie; Fuchs, Susanne

    2014-01-01

    Physiological rhythms are sensitive to social interactions and could contribute to defining social rhythms. Nevertheless, our knowledge of the implications of breathing in conversational turn exchanges remains limited. In this paper, we addressed the idea that breathing may contribute to timing and coordination between dialogue partners. The relationships between turns and breathing were analysed in unconstrained face-to-face conversations involving female speakers. No overall relationship between breathing and turn-taking rates was observed, as breathing rate was specific to the subjects' activity in dialogue (listening versus taking the turn versus holding the turn). A general inter-personal coordination of breathing over the whole conversation was not evident. However, specific coordinative patterns were observed in shorter time-windows when participants engaged in taking turns. The type of turn-taking had an effect on the respective coordination in breathing. Most of the smooth and interrupted turns were taken just after an inhalation, with specific profiles of alignment to partner breathing. Unsuccessful attempts to take the turn were initiated late in the exhalation phase and with no clear inter-personal coordination. Finally, breathing profiles at turn-taking were different than those at turn-holding. The results support the idea that breathing is actively involved in turn-taking and turn-holding. PMID:25385777

  14. Active breathing control (ABC): Determination and reduction of breathing-induced organ motion in the chest

    SciTech Connect

    Gagel, Bernd . E-mail: BGagel@UKAachen.de; Demirel, Cengiz M.P.; Kientopf, Aline; Pinkawa, Michael; Piroth, Marc; Stanzel, Sven; Breuer, Christian; Asadpour, Branka; Jansen, Thomas; Holy, Richard; Wildberger, Joachim E.; Eble, Michael J.

    2007-03-01

    Purpose: Extensive radiotherapy volumes for tumors of the chest are partly caused by interfractional organ motion. We evaluated the feasibility of respiratory observation tools using the active breathing control (ABC) system and the effect on breathing cycle regularity and reproducibility. Methods and Materials: Thirty-six patients with unresectable tumors of the chest were selected for evaluation of the ABC system. Computed tomography scans were performed at various respiratory phases starting at the same couch position without patient movement. Threshold levels were set at minimum and maximum volume during normal breathing cycles and at a volume defined as shallow breathing, reflecting the subjective maximal tolerable reduction of breath volume. To evaluate the extent of organ movement, 13 landmarks were considering using commercial software for image coregistration. In 4 patients, second examinations were performed during therapy. Results: Investigating the differences in a normal breathing cycle versus shallow breathing, a statistically significant reduction of respiratory motion in the upper, middle, and lower regions of the chest could be detected, representing potential movement reduction achieved through reduced breath volume. Evaluating interfraction reproducibility, the mean displacement ranged between 0.24 mm (chest wall/tracheal bifurcation) to 3.5 mm (diaphragm) for expiration and shallow breathing and 0.24 mm (chest wall) to 5.25 mm (diaphragm) for normal inspiration. Conclusions: By modifying regularity of the respiratory cycle through reduction of breath volume, a significant and reproducible reduction of chest and diaphragm motion is possible, enabling reduction of treatment planning margins.

  15. Take a breath and take the turn: how breathing meets turns in spontaneous dialogue.

    PubMed

    Rochet-Capellan, Amélie; Fuchs, Susanne

    2014-12-19

    Physiological rhythms are sensitive to social interactions and could contribute to defining social rhythms. Nevertheless, our knowledge of the implications of breathing in conversational turn exchanges remains limited. In this paper, we addressed the idea that breathing may contribute to timing and coordination between dialogue partners. The relationships between turns and breathing were analysed in unconstrained face-to-face conversations involving female speakers. No overall relationship between breathing and turn-taking rates was observed, as breathing rate was specific to the subjects' activity in dialogue (listening versus taking the turn versus holding the turn). A general inter-personal coordination of breathing over the whole conversation was not evident. However, specific coordinative patterns were observed in shorter time-windows when participants engaged in taking turns. The type of turn-taking had an effect on the respective coordination in breathing. Most of the smooth and interrupted turns were taken just after an inhalation, with specific profiles of alignment to partner breathing. Unsuccessful attempts to take the turn were initiated late in the exhalation phase and with no clear inter-personal coordination. Finally, breathing profiles at turn-taking were different than those at turn-holding. The results support the idea that breathing is actively involved in turn-taking and turn-holding.

  16. Delayed feedback applied to breathing in humans

    NASA Astrophysics Data System (ADS)

    Janson, N. B.; Pototsky, A.; Parkes, C.

    2013-10-01

    We studied the response of healthy volunteers to the delayed feedback generated from the breathing signals. Namely, in the freely-breathing volunteers the breathing signal was recorded, delayed by τ seconds and fed back to the same volunteer in real time in the form of a visual and auditory stimulus of low intensity, i.e. the stimulus was crucially non-intrusive. In each case volunteers were instructed to breathe in the way which was most comfortable for them, and no explanation about the kind of applied stimulus was provided to them. Each volunteer experienced 10 different delay times ranging between 10% and 100% of the average breathing period without external stimulus. It was observed that in a significant proportion of subjects (11 out of 24) breathing was slowed down in the presence of delayed feedback with moderate delay. Also, in 6 objects out of 24 the delayed feedback was able to induce transition from nearly periodic to irregular breathing. These observations are consistent with the phenomena observed in numerical simulation of the models of periodic and chaotic self-oscillations with delays, and also in experiments with simpler self-oscillating systems.

  17. Decreased chewing activity during mouth breathing.

    PubMed

    Hsu, H-Y; Yamaguchi, K

    2012-08-01

    This study examined the effect of mouth breathing on the strength and duration of vertical effect on the posterior teeth using related functional parameters during 3 min of gum chewing in 39 nasal breathers. A CO(2) sensor was placed over the mouth to detect expiratory airflow. When no airflow was detected from the mouth throughout the recording period, the subject was considered a nasal breather and enrolled in the study. Electromyographic (EMG) activity was recorded during 3 min of gum chewing. The protocol was repeated with the nostrils occluded. The strength of the vertical effect was obtained as integrated masseter muscle EMG activity, and the duration of vertical effect was also obtained as chewing stroke count, chewing cycle variation and EMG activity duration above baseline. Baseline activity was obtained from the isotonic EMG activity during jaw movement at 1.6 Hz without making tooth contact. The duration represented the percentage of the active period above baseline relative to the 3-min chewing period. Paired t-test and repeated analysis of variance were used to compare variables between nasal and mouth breathing. The integrated EMG activity and the duration of EMG activity above baseline, chewing stroke count and chewing cycle significantly decreased during mouth breathing compared with nasal breathing (P<0.05). Chewing cycle variance during mouth breathing was significantly greater than nasal breathing (P<0.05). Mouth breathing reduces the vertical effect on the posterior teeth, which can affect the vertical position of posterior teeth negatively, leading to malocclusion.

  18. An ultrasonic contactless sensor for breathing monitoring.

    PubMed

    Arlotto, Philippe; Grimaldi, Michel; Naeck, Roomila; Ginoux, Jean-Marc

    2014-01-01

    The monitoring of human breathing activity during a long period has multiple fundamental applications in medicine. In breathing sleep disorders such as apnea, the diagnosis is based on events during which the person stops breathing for several periods during sleep. In polysomnography, the standard for sleep disordered breathing analysis, chest movement and airflow are used to monitor the respiratory activity. However, this method has serious drawbacks. Indeed, as the subject should sleep overnight in a laboratory and because of sensors being in direct contact with him, artifacts modifying sleep quality are often observed. This work investigates an analysis of the viability of an ultrasonic device to quantify the breathing activity, without contact and without any perception by the subject. Based on a low power ultrasonic active source and transducer, the device measures the frequency shift produced by the velocity difference between the exhaled air flow and the ambient environment, i.e., the Doppler effect. After acquisition and digitization, a specific signal processing is applied to separate the effects of breath from those due to subject movements from the Doppler signal. The distance between the source and the sensor, about 50 cm, and the use of ultrasound frequency well above audible frequencies, 40 kHz, allow monitoring the breathing activity without any perception by the subject, and therefore without any modification of the sleep quality which is very important for sleep disorders diagnostic applications. This work is patented (patent pending 2013-7-31 number FR.13/57569). PMID:25140632

  19. The effect of body temperature on the dynamic respiratory system compliance-breathing frequency relationship in the rat.

    PubMed

    Rubini, Alessandro; Bosco, Gerardo

    2013-06-01

    The mechanical inhomogeneity of the respiratory system is frequently investigated by measuring the frequency dependence of dynamic compliance, but no data are currently available describing the effects of body temperature variations. The aim of the present report was to study those effects in vivo. Peak airway pressure was measured during positive pressure ventilation in eight anesthetized rats while breathing frequency (but not tidal volume) was altered. Dynamic compliance was calculated as the tidal volume/peak airway pressure, and measurements were taken in basal conditions (mean rectal temperature 37.3 °C) as well as after total body warming (mean rectal temperature 39.7 °C). Due to parenchymal mechanical inhomogeneity and stress relaxation-linked effects, the normal rat respiratory system exhibited frequency dependence of dynamic lung compliance. Even moderate body temperature increments significantly reduced the decrements in dynamic compliance linked to breathing rate increments. The results were analyzed using Student's and Wilcoxon's tests, which yielded the same results (p < 0.05). Body temperature variations are known to influence respiratory mechanics. The frequency dependence of dynamic compliance was found, in the experiments described, to be temperature-dependent as temperature variations affected parenchymal mechanical inhomogeneity and stress relaxation. These results suggest that body temperature variations should be taken into consideration when the dynamic compliance-breathing frequency relationship is being examined during clinical assessment of inhomogeneity of lung parenchyma in patients.

  20. Applications of breath gas analysis in medicine

    NASA Astrophysics Data System (ADS)

    Amann, Anton; Poupart, Guy; Telser, Stefan; Ledochowski, Maximilian; Schmid, Alex; Mechtcheriakov, Sergei

    2004-12-01

    Volatile organic compounds (VOCs) in exhaled breath gas provide valuable information about the subjects' physiological and pathophysiological condition. Proton-transfer-reaction mass spectrometry (PTR-MS) allows rapid and online measurements of these substances. We present results of three studies illustrating the potential of breath gas analysis by PTR-MS in various contexts: long-time online monitoring of VOCs in sleeping subjects suggests that VOC profiles are related to sleep stages. Analysis of VOC concentrations in the breath of carbohydrate malabsorbers emphasizes the role played by bacteria in the gut. Finally, we demonstrate the large intra- and intersubject concentration variability of VOCs by considering one particular mass.

  1. Tidal Streams Near and Far

    NASA Astrophysics Data System (ADS)

    Fardal, Mark A.

    2014-06-01

    The Pandas survey of stars in M31's disk and halo is crisscrossed by numerous tidal features from both M31 and the Milky Way. Here I focus on two narrow stellar streams visible in the survey. They have comparable angular extent in the survey (10-13 degrees long versus only 0.3 degree wide), but one is a local Milky Way stream at about 30 kpc and one is in M31, roughly 25 times more distant. I estimate the stellar mass and metallicity in the streams and the distance gradient along them. The kinematics of the M31 stream is sparsely sampled by red giant stars and globular clusters. Bayesian modeling of the stream data yields accurate constraints on the orbital parameters of the streams.

  2. Breathing strategy in master athletes and untrained elderly subjects according to the incremental protocol.

    PubMed

    Deruelle, Fabien; Nourry, Cédric; Mucci, Patrick; Bart, Frédéric; Grosbois, Jean-Marie; Lensel, Ghislaine; Fabre, Claudine

    2006-06-01

    To analyze the influence of step-duration protocol (1 vs. 3 min) on breathing strategy according to the physical fitness of healthy elderly subjects, this study compared the ventilatory responses and exercise tidal flow-volume loops (ETFVL) at the first and second ventilatory thresholds (VT(1) and VT(2)). Nineteen master athletes (mean age (+/- SD), 63.1 +/- 3.2 y; (.)VO(2)(max), 41.5 mL x (min x kg)(-1)) and 8 untrained elderly subjects (age, 65.5 +/- 2.3 y; (.)VO(2)(max), 25.8 mL x (min x kg)(-1)) performed 2 exhaustive exercise tests on a cycle ergometer. In untrained subjects, at VT(1) and VT(2), no significant difference was measured in ventilatory responses and ETFVL between protocols. Master athletes, at VT(2), presented a significantly higher (.)VCO(2) (P < 0.01), ventilation ((.)VE; P < 0.01), breathing frequency (f(b); P < 0.05), tidal volume relative to inspiratory capatcity (V(t)/IC) (P < 0.01),V(t) relative to forced vital capacity (V(t)/FVC; P < 0.05), and lower inspiratory reserve volume relative to FVC (IRV/FVC; P < 0.01) during the 1 min protocol than during the 3 min protocol. Master athletes, at maximal exercise, expressed significantly higher (.)VCO(2) (P < 0.01) and dyspnea (P < 0.05) with the shorter protocol. We concluded that, in untrained subjects, neither incremental exercise test had an impact on respiratory responses during exercise. Nevertheless, in master athletes, breathing strategy seems to be protocol dependent. The short test induced higher mechanical ventilatory constraints and dyspneic feeling than the long protocol, which could be explained by a higher (.)VE itself linked to a greater (.)VCO(2) and a higher blood lactate concentration.

  3. Atmospheric noise of a breaking tidal bore.

    PubMed

    Chanson, Hubert

    2016-01-01

    A tidal bore is a surge of waters propagating upstream in an estuary as the tidal flow turns to rising and the flood tide propagates into a funnel-shaped system. Large tidal bores have a marked breaking roller. The sounds generated by breaking tidal bores were herein investigated in the field (Qiantang River) and in laboratory. The sound pressure record showed two dominant periods, with some similarity with an earlier study [Chanson (2009). J. Acoust. Soc. Am. 125(6), 3561-3568]. The two distinct phases were the incoming tidal bore when the sound amplitude increased with the approaching bore, and the passage of the tidal bore in front of the microphone when loud and powerful noises were heard. The dominant frequency ranged from 57 to 131 Hz in the Qiantang River bore. A comparison between laboratory and prototype tidal bores illustrated both common features and differences. The low pitch sound of the breaking bore had a dominant frequency close to the collective oscillations of bubble clouds, which could be modeled with a bubble cloud model using a transverse dimension of the bore roller. The findings suggest that this model might be over simplistic in the case of a powerful breaking bore, like that of the Qiantang River.

  4. Characterization of free breathing patterns with 5D lung motion model

    SciTech Connect

    Zhao Tianyu; Lu Wei; Yang Deshan; Mutic, Sasa; Noel, Camille E.; Parikh, Parag J.; Bradley, Jeffrey D.; Low, Daniel A.

    2009-11-15

    Purpose: To determine the quiet respiration breathing motion model parameters for lung cancer and nonlung cancer patients. Methods: 49 free breathing patient 4DCT image datasets (25 scans, cine mode) were collected with simultaneous quantitative spirometry. A cross-correlation registration technique was employed to track the lung tissue motion between scans. The registration results were applied to a lung motion model: X-vector=X-vector{sub 0}+{alpha}-vector{beta}-vector f, where X-vector is the position of a piece of tissue located at reference position X-vector{sub 0} during a reference breathing phase (zero tidal volume v, zero airflow f). {alpha}-vector is a parameter that characterizes the motion due to air filling (motion as a function of tidal volume v) and {beta}-vector is the parameter that accounts for the motion due to the imbalance of dynamical stress distributions during inspiration and exhalation that causes lung motion hysteresis (motion as a function of airflow f). The parameters {alpha}-vector and {beta}-vector together provide a quantitative characterization of breathing motion that inherently includes the complex hysteresis interplay. The {alpha}-vector and {beta}-vector distributions were examined for each patient to determine overall general patterns and interpatient pattern variations. Results: For 44 patients, the greatest values of |{alpha}-vector| were observed in the inferior and posterior lungs. For the rest of the patients, |{alpha}-vector| reached its maximum in the anterior lung in three patients and the lateral lung in two patients. The hysteresis motion {beta}-vector had greater variability, but for the majority of patients, |{beta}-vector| was largest in the lateral lungs. Conclusions: This is the first report of the three-dimensional breathing motion model parameters for a large cohort of patients. The model has the potential for noninvasively predicting lung motion. The majority of patients exhibited similar |{alpha}-vector| maps

  5. Breathing patterns of preterm infants during bottle feeding: role of milk flow.

    PubMed

    Mathew, O P

    1991-12-01

    Milk flow achieved during feeding may contribute to the ventilatory depression observed during nipple feeding. One of the important determinants of milk flow is the size of the feeding hole. In the first phase of the study, investigators compared the breathing patterns of 10 preterm infants during bottle feeding with two types of commercially available (Enfamil) single-hole nipples: one type designed for term infants and the other for preterm infants. Reductions in ventilation, tidal volume, and breathing frequency, compared with prefeeding control values, were observed with both nipple types during continuous and intermittent sucking phases; no significant differences were observed for any of the variables. Unlike the commercially available, mechanically drilled nipples, laser-cut nipple units showed a markedly lower coefficient of variation in milk flow. In the second phase of the study, two sizes of laser-cut nipple units, low and high flow, were used to feed nine preterm infants. Significantly lower sucking pressures were observed with high-flow nipples as compared with low-flow nipples. Decreases in minute ventilation and breathing frequency were also significantly greater with high-flow nipples. These results suggest that milk flow contributes to the observed reduction in ventilation during nipple feeding and that preterm infants have limited ability to self-regulate milk flow.

  6. Remembering the past with slow breathing associated with activity in the parahippocampus and amygdala.

    PubMed

    Masaoka, Yuri; Sugiyama, Haruko; Katayama, Atsushi; Kashiwagi, Mitsuyoshi; Homma, Ikuo

    2012-07-19

    Breathing plays an important role in perception of odors and the experience of emotions. We used the dipole tracing method to analyze brain areas related to odor-induced autobiographical memory and emotions estimated from averaged electroencephalograms triggered by inspiration onset during odor presentation. Odor stimuli were perfumes subjects named that elicited a specific, pleasant and personal memory as well as two pleasant odors for controls. The perfumes induced specific emotional responses during memory retrieval, arousal level of the memory, feelings of pleasantness and a sense of familiarity with the odor. Respiration measurement indicated that tidal volume increased and respiratory frequency decreased during presentation of perfume stimuli, showing a deep and slow breathing pattern. Throughout the olfactory stimulation, electroencephalograms and respiration were simultaneously recorded. In the averaged potentials, low frequency oscillation was phase-locked to inspiration. Dipole analysis showed that perfumes activated more widespread areas of the right parahippocampal cortex and converged in the right amygdala compared to control odors. Slow breathing synchronized with odor-induced autobiographical memory and emotions may be subconsciously stored in the parahippocampal cortex and amygdala.

  7. 21 CFR 862.3050 - Breath-alcohol test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Breath-alcohol test system. 862.3050 Section 862....3050 Breath-alcohol test system. (a) Identification. A breath-alcohol test system is a device intened to measure alcohol in the human breath. Measurements obtained by this device are used in...

  8. 21 CFR 862.3050 - Breath-alcohol test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Breath-alcohol test system. 862.3050 Section 862....3050 Breath-alcohol test system. (a) Identification. A breath-alcohol test system is a device intened to measure alcohol in the human breath. Measurements obtained by this device are used in...

  9. 21 CFR 862.3050 - Breath-alcohol test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Breath-alcohol test system. 862.3050 Section 862....3050 Breath-alcohol test system. (a) Identification. A breath-alcohol test system is a device intened to measure alcohol in the human breath. Measurements obtained by this device are used in...

  10. 21 CFR 862.3050 - Breath-alcohol test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Breath-alcohol test system. 862.3050 Section 862....3050 Breath-alcohol test system. (a) Identification. A breath-alcohol test system is a device intened to measure alcohol in the human breath. Measurements obtained by this device are used in...

  11. 21 CFR 862.3050 - Breath-alcohol test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Breath-alcohol test system. 862.3050 Section 862....3050 Breath-alcohol test system. (a) Identification. A breath-alcohol test system is a device intened to measure alcohol in the human breath. Measurements obtained by this device are used in...

  12. 42 CFR 84.72 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Breathing tubes; minimum requirements. 84.72 Section 84.72 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL...-Contained Breathing Apparatus § 84.72 Breathing tubes; minimum requirements. Flexible breathing tubes...

  13. 42 CFR 84.72 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Breathing tubes; minimum requirements. 84.72 Section 84.72 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL...-Contained Breathing Apparatus § 84.72 Breathing tubes; minimum requirements. Flexible breathing tubes...

  14. 42 CFR 84.72 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Breathing tubes; minimum requirements. 84.72 Section 84.72 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL...-Contained Breathing Apparatus § 84.72 Breathing tubes; minimum requirements. Flexible breathing tubes...

  15. 42 CFR 84.72 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Breathing tubes; minimum requirements. 84.72 Section 84.72 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL...-Contained Breathing Apparatus § 84.72 Breathing tubes; minimum requirements. Flexible breathing tubes...

  16. 42 CFR 84.72 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Breathing tubes; minimum requirements. 84.72 Section 84.72 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL...-Contained Breathing Apparatus § 84.72 Breathing tubes; minimum requirements. Flexible breathing tubes...

  17. Tidal river dynamics: Implications for deltas

    NASA Astrophysics Data System (ADS)

    Hoitink, A. J. F.; Jay, D. A.

    2016-03-01

    Tidal rivers are a vital and little studied nexus between physical oceanography and hydrology. It is only in the last few decades that substantial research efforts have been focused on the interactions of river discharge with tidal waves and storm surges into regions beyond the limit of salinity intrusion, a realm that can extend inland hundreds of kilometers. One key phenomenon resulting from this interaction is the emergence of large fortnightly tides, which are forced long waves with amplitudes that may increase beyond the point where astronomical tides have become extinct. These can be larger than the linear tide itself at more landward locations, and they greatly influence tidal river water levels and wetland inundation. Exploration of the spectral redistribution and attenuation of tidal energy in rivers has led to new appreciation of a wide range of consequences for fluvial and coastal sedimentology, delta evolution, wetland conservation, and salinity intrusion under the influence of sea level rise and delta subsidence. Modern research aims at unifying traditional harmonic tidal analysis, nonparametric regression techniques, and the existing understanding of tidal hydrodynamics to better predict and model tidal river dynamics both in single-thread channels and in branching channel networks. In this context, this review summarizes results from field observations and modeling studies set in tidal river environments as diverse as the Amazon in Brazil, the Columbia, Fraser and Saint Lawrence in North America, the Yangtze and Pearl in China, and the Berau and Mahakam in Indonesia. A description of state-of-the-art methods for a comprehensive analysis of water levels, wave propagation, discharges, and inundation extent in tidal rivers is provided. Implications for lowland river deltas are also discussed in terms of sedimentary deposits, channel bifurcation, avulsion, and salinity intrusion, addressing contemporary research challenges.

  18. An introduction to the psychophysiology of breathing.

    PubMed

    Ley, R

    1994-06-01

    Breathing can be viewed as an independent variable which affects emotion, cognition, and behavior as well as a dependent variable which reflects changes in emotion, cognition, and behavior. This bidirectional interaction is basic to an appreciation of the significance of breathing in terms of its relevance in research and application. The underlying premise of the present article is that since breathing is a behavior that is under voluntary as well as reflexive control, it can be modified according to the principles of both instrumental training (operant conditioning) and Pavlovian (classical) conditioning. The implications of this premise are relevant to theory, diagnosis, and treatment of stress and anxiety-related disorders (e.g., panic disorder, phobias, test anxiety, occupational strain, and related psychosomatic disorders), and to basic and applied research in the psychophysiology of breathing.

  19. Portable breathing apparatus for coal mines

    NASA Technical Reports Server (NTRS)

    Vandolah, R. W.

    1972-01-01

    The state of the art in portable oxygen breathing equipment is reported. Considered are self-containing as well as chemically generating oxygen sources and their effectiveness and limitations in mine rescue operations.

  20. Coordination of Mastication, Swallowing and Breathing

    PubMed Central

    Matsuo, Koichiro; Palmer, Jeffrey B.

    2009-01-01

    Summary The pathways for air and food cross in the pharynx. In breathing, air may flow through either the nose or the mouth, it always flows through the pharynx. During swallowing, the pharynx changes from an airway to a food channel. The pharynx is isolated from the nasal cavity and lower airway by velopharyngeal and laryngeal closure during the pharyngeal swallow. During mastication, the food bolus accumulates in the pharynx prior to swallow initiation. The structures in the oral cavity, pharynx and larynx serve multiple functions in breathing, speaking, mastication and swallowing. Thus, the fine temporal coordination of feeding among breathing, mastication and swallowing is essential to provide proper food nutrition and to prevent pulmonary aspiration. This review paper will review the temporo-spatial coordination of the movements of oral, pharyngeal, and laryngeal structures during mastication and swallowing, and temporal coordination between breathing, mastication, and swallowing. PMID:20161022

  1. Does a Smaller Waist Mean Smelly Breath?

    MedlinePlus

    ... overnight on the surface of the tongue when saliva production is diminished." ; Tips to combat halitosis: ; 1. Drink ... after meals can help keep bad breath away. Saliva production increases during chewing and this can help neutralize ...

  2. Alcohol breath test: gas exchange issues.

    PubMed

    Hlastala, Michael P; Anderson, Joseph C

    2016-08-01

    The alcohol breath test is reviewed with a focus on gas exchange factors affecting its accuracy. The basis of the alcohol breath test is the assumption that alveolar air reaches the mouth during exhalation with no change in alcohol concentration. Recent investigations have shown that alcohol concentration is altered during its transit to the mouth. The exhaled alcohol concentration is modified by interaction with the mucosa of the pulmonary airways. Exhaled alcohol concentration is not an accurate indicator of alveolar alcohol concentration. Measuring alcohol concentration in the breath is very different process than measuring a blood level from air equilibrated with a blood sample. Airway exchange of alcohol leads to a bias against certain individuals depending on the anatomic and physiologic characteristics. Methodological modifications are proposed to improve the accuracy of the alcohol breath test to become fair to all. PMID:27197859

  3. Haemoptysis after breath-hold diving.

    PubMed

    Boussuges, A; Pinet, C; Thomas, P; Bergmann, E; Sainty, J M; Vervloet, D

    1999-03-01

    Pulmonary oedema has been described in swimmers and self-contained underwater breathing apparatus (Scuba) divers. This study reports three cases of haemoptysis secondary to alveolar haemorrhage in breath-hold divers. Contributory factors, such as haemodynamic modifications secondary to immersion, cold exposure, exercise and exposure to an increase in ambient pressure, could explain this type of accident. Furthermore, these divers had taken aspirin, which may have aggravated the bleeding.

  4. Melting of Io by tidal dissipation

    NASA Technical Reports Server (NTRS)

    Peale, S. J.; Cassen, P.; Reynolds, R. T.

    1979-01-01

    The resonant structure of Io leads to forced eccentricities that are considerably larger than the free values. Although still modest by all standards, these forced eccentricities coupled with the enormous tides induced by Jupiter lead to magnitudes of tidal dissipation that are large enough to completely dominate the thermal history of Io. In the present paper, the forced eccentricities are calculated and then substituted into an expression for the total tidal dissipation. The results point to the possibility that the dissipation of tidal energy in Io may have melted a major fraction of Io's mass.

  5. Evolution of satellite resonances by tidal dissipation.

    NASA Technical Reports Server (NTRS)

    Greenberg, R.

    1973-01-01

    Analysis of a realistic model shows how satellites' gravitational interaction can halt their differential tidal evolution when resonant commensurabilities of their orbital periods are reached. The success of this study lends support to the hypothesis that orbit-orbit resonances among satellites in the solar system, including the Titan-Hyperion case, did evolve as a result of tidal energy dissipation. Consideration of the time scale for this evolution process, possible now that the capture mechanism has been revealed, can offer more sophisticated constraints on the tidal dissipation function, Q, and on past orbital conditions.

  6. ON THE TIDAL DISSIPATION OF OBLIQUITY

    SciTech Connect

    Rogers, T. M.; Lin, D. N. C. E-mail: lin@ucolick.org

    2013-05-20

    We investigate tidal dissipation of obliquity in hot Jupiters. Assuming an initial random orientation of obliquity and parameters relevant to the observed population, the obliquity of hot Jupiters does not evolve to purely aligned systems. In fact, the obliquity evolves to either prograde, retrograde, or 90 Degree-Sign orbits where the torque due to tidal perturbations vanishes. This distribution is incompatible with observations which show that hot Jupiters around cool stars are generally aligned. This calls into question the viability of tidal dissipation as the mechanism for obliquity alignment of hot Jupiters around cool stars.

  7. Dynamical response to a stationary tidal field

    NASA Astrophysics Data System (ADS)

    Landry, Philippe; Poisson, Eric

    2015-12-01

    We demonstrate that a slowly rotating compact body subjected to a stationary tidal field undergoes a dynamical response, in which the fluid variables and the interior metric vary on the time scale of the rotation period. This dynamical response requires the tidal field to have a gravitomagnetic component generated by external mass currents; the response to a gravitoelectric tidal field is stationary. We confirm that in a calculation carried out to first order in the body's rotation, the exterior geometry bears no trace of this internal dynamics; it remains stationary in spite of the time-dependent interior.

  8. Extreme human breath-hold diving.

    PubMed

    Ferretti, G

    2001-04-01

    In this paper, the respiratory, circulatory and metabolic adjustments to human extreme breath-hold diving are reviewed. A survey of the literature reveals that in extreme divers, adaptive mechanisms take place that allow prolongation of apnoea beyond the limits attained by non-diving subjects, and preservation of oxygen stores during the dives. The occurrence of a diving response, including peripheral vasoconstriction, increased arterial blood pressure, bradycardia and lowered cardiac output, is strongly implicated. Some peripheral regions may be excluded from perfusion, with consequent reliance on anaerobic metabolism. In addition, extreme breath-hold divers show a blunted ventilatory response to carbon dioxide breathing, possibly as a consequence of frequent exposure to high carbon dioxide partial pressures during the dives. These mechanisms allow the attainment of particularly low alveolar oxygen (< 30 mmHg) and high alveolar carbon dioxide (> 50 mmHg) partial pressures at the end of maximal dry breath-holds, and reduce oxygen consumption during the dive at the expense of increased anaerobic glycolysis (rate of blood lactate accumulation > 0.04 mM.s-1). The current absolute world record for depth in breath-hold diving is 150 m. Its further improvement depends upon how far the equilibrium between starting oxygen stores, the overall rate of energy expenditure, the fraction of energy provided by anaerobic metabolism and the diving speed can be pushed, with consciousness upon emersion. The ultimate limit to breath-hold diving records may indeed be imposed by an energetic constraint. PMID:11374109

  9. Monitoring breath markers under controlled conditions.

    PubMed

    Righettoni, Marco; Ragnoni, Alessandro; Güntner, Andreas T; Loccioni, Claudio; Pratsinis, Sotiris E; Risby, Terence H

    2015-12-01

    Breath analysis has the potential to detect and monitor diseases as well as to reduce the corresponding medical costs while improving the quality of a patient's life. Herein, a portable prototype, consisting of a commercial breath sampler modified to work as a platform for solid-state gas sensors was developed. The sensor is placed close to the mouth (<10 cm) and minimizes the mouth-to-sensor path to avoid contamination and dilution of the target breath marker. Additionally with an appropriate cooling concept, even high sensor operating temperatures (e.g. 350 °C) could be used. Controlled sampling is crucial for accurate repeatable analysis of the human breath and these concerns have been addressed by this novel prototype. The device helps a subject control their exhaled flow rate which increases reproducibility of intra-subject breath samples. The operation of this flame-made selective chemo-resistive gas sensor is demonstrated by the detection of breath acetone. PMID:26469378

  10. Hydrogen breath tests in gastrointestinal diseases.

    PubMed

    Rana, Satya Vati; Malik, Aastha

    2014-10-01

    Hydrogen breath tests are widely used to explore pathophysiology of functional gastrointestinal (GI) disorders. Small intestinal bacterial overgrowth (SIBO) and carbohydrate malabsorption are disorders detected by these tests that have been proposed to be of great importance for symptoms of GI diseases. Glucose hydrogen breath test is more acceptable for diagnosis of SIBO whereas lactose and fructose hydrogen breath tests are used for detection of lactose and fructose maldigestion respectively. Lactulose hydrogen breath test is also used widely to measure the orocecal transit time for GI motility. These methods are noninvasive and inexpensive. Many patients with functional gut disorders are unaware of the relationship between diet and GI symptoms they present. In particular, patients with chronic symptoms may regard their condition as normal and may not be aware that their symptoms can be effectively managed following a proper diagnosis. Patients with symptoms of abdominal pain, bloating, flatulence and altered bowel movements (diarrhea and constipation), or with a medical diagnosis of irritable bowel syndrome or celiac disease, may have undiagnosed carbohydrate malabsorption or SIBO. Hydrogen breath tests are specific and sensitive diagnostic tests that can be used to either confirm or eliminate the possibility of carbohydrate malabsorption or SIBO in such patients. Breath tests, though valuable tools, are underutilized in evaluating dyspepsia and functional bloating and diarrhea as well as suspected malabsorption. However, because of their simplicity, reproducibility and safety of procedure they are now being substituted to more uncomfortable and expensive techniques that were traditionally used in gastroenterology. PMID:25298621

  11. Optoacoustic 13C-breath test analyzer

    NASA Astrophysics Data System (ADS)

    Harde, Hermann; Helmrich, Günther; Wolff, Marcus

    2010-02-01

    The composition and concentration of exhaled volatile gases reflects the physical ability of a patient. Therefore, a breath analysis allows to recognize an infectious disease in an organ or even to identify a tumor. One of the most prominent breath tests is the 13C-urea-breath test, applied to ascertain the presence of the bacterium helicobacter pylori in the stomach wall as an indication of a gastric ulcer. In this contribution we present a new optical analyzer that employs a compact and simple set-up based on photoacoustic spectroscopy. It consists of two identical photoacoustic cells containing two breath samples, one taken before and one after capturing an isotope-marked substrate, where the most common isotope 12C is replaced to a large extent by 13C. The analyzer measures simultaneously the relative CO2 isotopologue concentrations in both samples by exciting the molecules on specially selected absorption lines with a semiconductor laser operating at a wavelength of 2.744 μm. For a reliable diagnosis changes of the 13CO2 concentration of 1% in the exhaled breath have to be detected at a concentration level of this isotope in the breath of about 500 ppm.

  12. Control of breathing in invertebrate model systems.

    PubMed

    Bell, Harold J; Syed, Naweed I

    2012-07-01

    The invertebrates have adopted a myriad of breathing strategies to facilitate the extraction of adequate quantities of oxygen from their surrounding environments. Their respiratory structures can take a wide variety of forms, including integumentary surfaces, lungs, gills, tracheal systems, and even parallel combinations of these same gas exchange structures. Like their vertebrate counterparts, the invertebrates have evolved elaborate control strategies to regulate their breathing activity. Our goal in this article is to present the reader with a description of what is known regarding the control of breathing in some of the specific invertebrate species that have been used as model systems to study different mechanistic aspects of the control of breathing. We will examine how several species have been used to study fundamental principles of respiratory rhythm generation, central and peripheral chemosensory modulation of breathing, and plasticity in the control of breathing. We will also present the reader with an overview of some of the behavioral and neuronal adaptability that has been extensively documented in these animals. By presenting explicit invertebrate species as model organisms, we will illustrate mechanistic principles that form the neuronal foundation of respiratory control, and moreover appear likely to be conserved across not only invertebrates, but vertebrate species as well. PMID:23723022

  13. Contributions of tidal lung inflation to human R-R interval and arterial pressure fluctuations.

    PubMed

    Koh, J; Brown, T E; Beightol, L A; Eckberg, D L

    1998-01-19

    We studied the effects of mechanical lung inflation on respiratory frequency R-R interval and arterial pressure fluctuations in nine healthy young adults undergoing elective orthopedic surgery. We conducted this research to define the contribution of pulmonary and thoracic stretch receptor input to respiratory sinus arrhythmia. We compared fast Fourier transform spectral power during three modes of ventilation: (1) spontaneous, frequency-controlled (0.25 Hz) breathing, (2) intermittent positive pressure ventilation (0.25 Hz, with a tidal volume of 8 ml/kg) and (3) high frequency jet ventilation (5.0 Hz, 2.5 kg/cm2), after sedation and vecuronium paralysis. Mean R-R intervals, arterial pressures and arterial blood gas levels were comparable during all three breathing conditions. Respiratory frequency systolic pressure spectral power was comparable during spontaneous breathing and conventional mechanical ventilation, but was significantly reduced during high frequency jet ventilation (P < 0.05). Respiratory frequency R-R interval spectral power (used as an index of respiratory sinus arrhythmia) declined dramatically with sedation and muscle paralysis (P < 0.05), but was greater during conventional mechanical, than high frequency jet ventilation (P < 0.05). These results suggest that although phasic inputs from pulmonary and thoracic stretch receptors make a statistically significant contribution to respiratory sinus arrhythmia, that contribution is small.

  14. Contributions of tidal lung inflation to human R-R interval and arterial pressure fluctuations

    NASA Technical Reports Server (NTRS)

    Koh, J.; Brown, T. E.; Beightol, L. A.; Eckberg, D. L.

    1998-01-01

    We studied the effects of mechanical lung inflation on respiratory frequency R-R interval and arterial pressure fluctuations in nine healthy young adults undergoing elective orthopedic surgery. We conducted this research to define the contribution of pulmonary and thoracic stretch receptor input to respiratory sinus arrhythmia. We compared fast Fourier transform spectral power during three modes of ventilation: (1) spontaneous, frequency-controlled (0.25 Hz) breathing, (2) intermittent positive pressure ventilation (0.25 Hz, with a tidal volume of 8 ml/kg) and (3) high frequency jet ventilation (5.0 Hz, 2.5 kg/cm2), after sedation and vecuronium paralysis. Mean R-R intervals, arterial pressures and arterial blood gas levels were comparable during all three breathing conditions. Respiratory frequency systolic pressure spectral power was comparable during spontaneous breathing and conventional mechanical ventilation, but was significantly reduced during high frequency jet ventilation (P < 0.05). Respiratory frequency R-R interval spectral power (used as an index of respiratory sinus arrhythmia) declined dramatically with sedation and muscle paralysis (P < 0.05), but was greater during conventional mechanical, than high frequency jet ventilation (P < 0.05). These results suggest that although phasic inputs from pulmonary and thoracic stretch receptors make a statistically significant contribution to respiratory sinus arrhythmia, that contribution is small.

  15. Underwater Stroke Kinematics During Breathing and Breath-holding Front Crawl Swimming.

    PubMed

    Vezos, Nickos; Gourgoulis, Vassilios; Aggeloussis, Nickos; Kasimatis, Panagiotis; Christoforidis, Christos; Mavromatis, Giorgos

    2007-01-01

    The aim of the present study was to determine the effects of breathing on the three - dimensional underwater stroke kinematics of front crawl swimming. Ten female competitive freestyle swimmers participated in the study. Each subject swam a number of front crawl trials of 25 m at a constant speed under breathing and breath-holding conditions. The underwater motion of each subject's right arm was filmed using two S-VHS cameras, operating at 60 Hz, which were positioned behind two underwater viewing windows. The spatial coordinates of selected points were calculated using the DLT procedure with 30 control points and after the digital filtering of the raw data with a cut-off frequency of 6 Hz, the hand's linear displacements and velocities were calculated. The results revealed that breathing caused significantly increases in the stroke duration (t9 = 2.764; p < 0.05), the backward hand displacement relative to the water (t9 = 2.471; p<0.05) and the lateral displacement of the hand in the X - axis during the downsweep (t9 = 2.638; p < 0.05). On the contrary, the peak backward hand velocity during the insweep (t9 = 2.368; p < 0.05) and the displacement of the hand during the push phase (t9 = -2.297; p < 0.05) were greatly reduced when breathing was involved. From the above, it was concluded that breathing action in front crawl swimming caused significant modifications in both the basic stroke parameters and the overall motor pattern were, possibly due to body roll during breathing. Key pointsThe breathing action increases the duration of the total underwater pull.The breathing action increases the absolute backward displacement of the hand.The breathing action caused significant modifications in the overall motor pattern, possibly due to body roll during breathing. PMID:24149225

  16. Upper limb kinematic differences between breathing and non-breathing conditions in front crawl sprint swimming.

    PubMed

    McCabe, Carla B; Sanders, Ross H; Psycharakis, Stelios G

    2015-11-26

    The purpose of this study was to determine whether the breathing action in front crawl (FC) sprint swimming affects the ipsilateral upper limb kinematics relative to a non-breathing stroke cycle (SC). Ten male competitive swimmers performed two 25m FC sprints: one breathing to their preferred side (Br) and one not breathing (NBr). Both swim trials were performed through a 6.75m(3) calibrated space and recorded by six gen-locked JVC KY32 CCD cameras. A paired t-test was used to assess statistical differences between the trials, with a confidence level of p<0.05 accepted as significant. Swimmers were slower (3%) when breathing. Within the entry phase, swimmers had a slower COM horizontal velocity (3.3%), less shoulder flexion (8%), abduction (33%) and roll (4%) when breathing. The pull phase was longer in duration (14%) swimmers had a shallower hand path (11%), less shoulder abduction (11%), a slower hand vertical acceleration (30%) and slower centre of mass (COM) horizontal velocity (3%) when breathing. In the push phase, swimmers had a smaller elbow range of motion (ROM) (38%), faster backwards hand speed (25%) and faster hand vertical acceleration (33%) when breathing. Swimmers rolled their shoulders more (12%) in the recovery phase when breathing. This study confirms that swim performance is compromised by the inclusion of taking a breath in sprint FC swimming. It was proposed that swimmers aim to orient their ipsilateral shoulder into a stronger position by stretching and rolling the shoulders more in the entry phase whilst preparing to take a breath. Swimmers should focus on lengthening the push phase by extending the elbow more and not accelerating the hand too quickly upwards when preparing to inhale. PMID:26456423

  17. Upper limb kinematic differences between breathing and non-breathing conditions in front crawl sprint swimming.

    PubMed

    McCabe, Carla B; Sanders, Ross H; Psycharakis, Stelios G

    2015-11-26

    The purpose of this study was to determine whether the breathing action in front crawl (FC) sprint swimming affects the ipsilateral upper limb kinematics relative to a non-breathing stroke cycle (SC). Ten male competitive swimmers performed two 25m FC sprints: one breathing to their preferred side (Br) and one not breathing (NBr). Both swim trials were performed through a 6.75m(3) calibrated space and recorded by six gen-locked JVC KY32 CCD cameras. A paired t-test was used to assess statistical differences between the trials, with a confidence level of p<0.05 accepted as significant. Swimmers were slower (3%) when breathing. Within the entry phase, swimmers had a slower COM horizontal velocity (3.3%), less shoulder flexion (8%), abduction (33%) and roll (4%) when breathing. The pull phase was longer in duration (14%) swimmers had a shallower hand path (11%), less shoulder abduction (11%), a slower hand vertical acceleration (30%) and slower centre of mass (COM) horizontal velocity (3%) when breathing. In the push phase, swimmers had a smaller elbow range of motion (ROM) (38%), faster backwards hand speed (25%) and faster hand vertical acceleration (33%) when breathing. Swimmers rolled their shoulders more (12%) in the recovery phase when breathing. This study confirms that swim performance is compromised by the inclusion of taking a breath in sprint FC swimming. It was proposed that swimmers aim to orient their ipsilateral shoulder into a stronger position by stretching and rolling the shoulders more in the entry phase whilst preparing to take a breath. Swimmers should focus on lengthening the push phase by extending the elbow more and not accelerating the hand too quickly upwards when preparing to inhale.

  18. Half Moon Cove Tidal Project. Feasibility report

    NASA Astrophysics Data System (ADS)

    1980-11-01

    The project would be located in a small cove in the northern part of Cobscook Bay in the vicinity of Eastport, Maine. The basin impounded by the barrier when full will approximate 1.2 square miles. The average tidal range at Eastport is 18.2 feet. The maximum spring tidal range will be 26.2 feet and the neap tidal range 12.8 feet. The project will be of the single pool-type single effect in which generation takes place on the ebb tide only. Utilizing an average mean tidal range of 18.2 feet the mode of operation enables generation for approximately ten and one-half (10-1/2) hours per day or slightly in excess of five (5) hours per tide. The installed capacity will be 12 MW utilizing 2 to 6 MW units. An axial flow, or Bulb type of turbine was selected for this study.

  19. Lunar Tidal Deformation and the Deep Interior

    NASA Astrophysics Data System (ADS)

    Williams, James G.; Konopliv, Alex S.; Park, Ryan; Boggs, Dale H.; Asmar, Sami W.; Yuan, Dah-Ning; Ratcliff, James; Watkins, Michael M.; Smith, David E.; Zuber, Maria

    2016-10-01

    The gravitational attractions of the Earth and Sun raise tides on the Moon. The amplitudes of vertical tidal variations are typically 0.1 to 0.15 m in size. The GRAIL mission determines the potential Love number k2 = 0.02422 with <1% uncertainty. Models with a crust, mantle, deep dissipating region, and fluid core can match the k2. Lunar Laser Ranging determines tidal dissipation Q=38 at 1 month period and Q=41 at 1 yr. Dissipation in the deep mantle appears to cause the low tidal Q and Q versus tidal period is a clue about the dissipation mechanism. The dissipating region has an upper radius of at least 535 km. The vertical displacement Love number h2 is detected.

  20. Morphodynamics of tidal networks: advances and challenges

    NASA Astrophysics Data System (ADS)

    Coco, G.; Olabarrieta, M.; van Maanen, B.; Zhou, Z.; Tinoco, R.

    2012-12-01

    Tidal embayments are complex environments at the boundary between land and sea. Their evolution, natural or human-induced, feeds back onto ecological, economic and societal functions. Overall, the ability to manage tidal embayments successfully and maintain their value hinges on our knowledge of the system. The morphological behaviour of tidal embayments, however, is very complex because of the variety of feedback mechanisms which lead to morphological change. In recent years, numerical studies have highlighted that the feedback between the hydrodynamics, sediment transport and morphological evolution can lead to the development of tidally-forced morphological networks characterized by slowly-evolving bifurcating channels. Both tidal range and the initial bathymetry appear to have a strong control on the morphological characteristics of the tidal network by affecting final basin hypsometry and channel patterns. Although promising, none of the numerical models presented in the literature and capable of simulating the growth of a tidal network have been scrutinized against field or laboratory data. Here, we show and discuss the performance of one of those numerical models against detailed laboratory data. Preliminary results indicate that numerical simulations can reproduce the general features of pattern development but that a better description of many fast- and small-scale processes is needed to achieve better model-data agreement. Unsurprisingly, the model shows a strong sensitivity to frictional effects and resuspension parameterizations. Numerical models of morphodynamics tend to neglect some physical or biological processes that affect the short- and long-term evolution of tidal networks. In terms of physical processes, wind waves, interacting with the ebb shoal and tidal currents at the mouth of the embayment can significantly affect hydro- and morphodynamics. Under high wave conditions waves can break in the inlet area producing wave induced circulation

  1. Tidal Despinning Timescales in the Solar System

    NASA Astrophysics Data System (ADS)

    Chyba, C. F.; Thomas, P. J.

    1998-09-01

    Planets and satellites in the Solar System despin to a spin-evolved end-state due to tidal dissipation. The usual derivation for the despinning timescale sets the change in spin angular momentum equal to to the gravitational torque acting on the object's tidal bulge (MacDonald 1964, Goldreich and Soter 1966, Peale 1974, 1977). The despinning timescale is found to be proportional to the difference between the initial and final spin angular velocities, and is finite. However, this approximate derivation ignores the orbital mean motion n of the despinning object, and is less and less satisfactory as the object.s spin angular velocity w approaches n. We have instead calculated tidal despinning times by applying the formalism of Peale and Cassen (1978) to calculate tidal energy dissipation due to tides raised on a non-spin-locked object. Tidal heating in the latter case is larger than tidal heating in the spin locked case by a factor (1/7)[(w-n)/n](1/e(2) ), where e is the orbital eccentricity. This factor is initially greater than 10(4) for many objects in the Solar System. Calculating despinning times from energy loss, we find that the despinning timescale includes a previously neglected term that goes to infinity logarithmically as w approaches n. In this sense all despinning timescales are in fact infinite. We therefore define an effective despinning timescale as the time required for despin tidal heating to fall below tidal heating due to orbital eccentricity. For many satellites in the Solar System, including such major moons as Io and Europa, the neglected term in the despinning timescale is in fact the dominant term. For some especially short-period satellites, such as Phobos or Amalthea, the resulting despinning timescales are one to two orders of magnitude longer than those previously accepted.

  2. Free-breathing respiratory motion of the heart measured from x-ray coronary angiograms (Second Place Student Paper Award)

    NASA Astrophysics Data System (ADS)

    Shechter, Guy; Ozturk, Cengizhan; Resar, Jon R.; McVeigh, Elliot R.

    2004-04-01

    Respiratory motion compensation for cardiac imaging requires knowledge of the heart's motion and deformation during breathing. We propose a method for measuring the natural tidal respiratory motion of the heart using free breathing coronary angiograms. A 3D deformation field describing the cardiac and respiratory motion of the coronary arteries is recovered from a biplane acquisition. Cardiac and respiratory phase are assigned to the images from an ECG signal synchronized to the image acquisition, and from the diaphragmatic displacement as observed in the images. The resulting motion field is decomposed into cardiac and respiratory components by fitting the field with periodic 2D parametric functions, where one dimension spans one cardiac cycle, and the second dimension spans one respiratory cycle. The method is applied to patient datasets, and an analysis of respiratory motion of the heart is presented.

  3. External work output and force generation during synchronized intermittent mechanical ventilation. Effect of machine assistance on breathing effort.

    PubMed

    Marini, J J; Smith, T C; Lamb, V J

    1988-11-01

    We measured the mechanical work performed by 12 acutely ill patients during synchronized intermittent mandatory ventilation to determine the influence of volume-cycled machine assistance on inspiratory timing, respiratory muscle force development, and external work output. The frequency and tidal volume of spontaneous breaths increased at lower levels of mechanical ventilation, but inspiratory time fraction did not vary across the spectrum of machine support. As machine support was withdrawn, inspiratory work and pressure-time product increased progressively for both spontaneous and assisted breathing cycles. On a per cycle basis, work output was greater for assisted than for spontaneous breaths at all levels of comparison. Although the mean pressure developed by the patient during assisted cycles averaged approximately equal to 20% less than during adjacent unassisted cycles, contraction time averaged approximately equal to 20% longer, so that the pressure-time products were nearly equivalent for both types of cycle. Two indices of force reserve indicated that our patients taxed their maximal ventilatory capability at all but the highest levels of support. We conclude that under the conditions of this study the ventilatory pump continued to be active at all levels of machine assistance. Although work per liter related linearly to the proportion of minute ventilation borne by the patient, force generation differed little for spontaneous and machine-aided breaths at any specified level of support. Whether judged on the basis of mean developed pressure (work per liter of ventilation) or pressure-time product, little effort adaptation to volume-cycled machine assistance appears to occur on a breath-by-breath basis.

  4. VISCOELASTIC MODELS OF TIDALLY HEATED EXOMOONS

    SciTech Connect

    Dobos, Vera; Turner, Edwin L.

    2015-05-01

    Tidal heating of exomoons may play a key role in their habitability, since the elevated temperature can melt the ice on the body even without significant solar radiation. The possibility of life has been intensely studied on solar system moons such as Europa or Enceladus where the surface ice layer covers a tidally heated water ocean. Tidal forces may be even stronger in extrasolar systems, depending on the properties of the moon and its orbit. To study the tidally heated surface temperature of exomoons, we used a viscoelastic model for the first time. This model is more realistic than the widely used, so-called fixed Q models because it takes into account the temperature dependence of the tidal heat flux and the melting of the inner material. Using this model, we introduced the circumplanetary Tidal Temperate Zone (TTZ), which strongly depends on the orbital period of the moon and less on its radius. We compared the results with the fixed Q model and investigated the statistical volume of the TTZ using both models. We have found that the viscoelastic model predicts 2.8 times more exomoons in the TTZ with orbital periods between 0.1 and 3.5 days than the fixed Q model for plausible distributions of physical and orbital parameters. The viscoelastic model provides more promising results in terms of habitability because the inner melting of the body moderates the surface temperature, acting like a thermostat.

  5. Tidal Interactions in Merging White Dwarf Binaries

    NASA Astrophysics Data System (ADS)

    Piro, Anthony L.

    2011-10-01

    The recently discovered system J0651 is the tightest known detached white dwarf (WD) binary. Since it has not yet initiated Roche-lobe overflow, it provides a relatively clean environment for testing our understanding of tidal interactions. I investigate the tidal heating of each WD, parameterized in terms of its tidal Q parameter. Assuming that the heating can be radiated efficiently, the current luminosities are consistent with Q 1 ≈ 7 × 1010 and Q 2 ≈ 2 × 107, for the He and C/O WDs, respectively. Conversely, if the observed luminosities are merely from the cooling of the WDs, these estimated values of Q represent the upper limits. A large Q 1 for the He WD means its spin velocity will be slower than that expected if it was tidally locked, which, since the binary is eclipsing, may be measurable via the Rossiter-McLaughlin effect. After one year, gravitational wave emission shifts the time of eclipses by 5.5 s, but tidal interactions cause the orbit to shrink more rapidly, changing the time by up to an additional 0.3 s after a year. Future eclipse timing measurements may therefore infer the degree of tidal locking.

  6. Viscoelastic Models of Tidally Heated Exomoons

    NASA Astrophysics Data System (ADS)

    Dobos, Vera; Turner, Edwin L.

    2015-05-01

    Tidal heating of exomoons may play a key role in their habitability, since the elevated temperature can melt the ice on the body even without significant solar radiation. The possibility of life has been intensely studied on solar system moons such as Europa or Enceladus where the surface ice layer covers a tidally heated water ocean. Tidal forces may be even stronger in extrasolar systems, depending on the properties of the moon and its orbit. To study the tidally heated surface temperature of exomoons, we used a viscoelastic model for the first time. This model is more realistic than the widely used, so-called fixed Q models because it takes into account the temperature dependence of the tidal heat flux and the melting of the inner material. Using this model, we introduced the circumplanetary Tidal Temperate Zone (TTZ), which strongly depends on the orbital period of the moon and less on its radius. We compared the results with the fixed Q model and investigated the statistical volume of the TTZ using both models. We have found that the viscoelastic model predicts 2.8 times more exomoons in the TTZ with orbital periods between 0.1 and 3.5 days than the fixed Q model for plausible distributions of physical and orbital parameters. The viscoelastic model provides more promising results in terms of habitability because the inner melting of the body moderates the surface temperature, acting like a thermostat.

  7. Half Moon Cove Tidal Project. Feasibility report

    SciTech Connect

    Not Available

    1980-11-01

    The proposed Half Moon Cove Tidal Power Project would be located in a small cove in the northern part of Cobscook Bay in the vicinity of Eastport, Maine. The project would be the first tidal electric power generating plant in the United States of America. The basin impounded by the barrier when full will approximate 1.2 square miles. The average tidal range at Eastport is 18.2 feet. The maximum spring tidal range will be 26.2 feet and the neap tidal range 12.8 feet. The project will be of the single pool-type single effect in which generation takes place on the ebb tide only. Utilizing an average mean tidal range of 18.2 feet the mode of operation enables generation for approximately ten and one-half (10-1/2) hours per day or slightly in excess of five (5) hours per tide. The installed capacity will be 12 MW utilizing 2 to 6 MW units. An axial flow, or Bulb type of turbine was selected for this study.

  8. TIDAL INTERACTIONS IN MERGING WHITE DWARF BINARIES

    SciTech Connect

    Piro, Anthony L.

    2011-10-20

    The recently discovered system J0651 is the tightest known detached white dwarf (WD) binary. Since it has not yet initiated Roche-lobe overflow, it provides a relatively clean environment for testing our understanding of tidal interactions. I investigate the tidal heating of each WD, parameterized in terms of its tidal Q parameter. Assuming that the heating can be radiated efficiently, the current luminosities are consistent with Q {sub 1} {approx} 7 x 10{sup 10} and Q {sub 2} {approx} 2 x 10{sup 7}, for the He and C/O WDs, respectively. Conversely, if the observed luminosities are merely from the cooling of the WDs, these estimated values of Q represent the upper limits. A large Q {sub 1} for the He WD means its spin velocity will be slower than that expected if it was tidally locked, which, since the binary is eclipsing, may be measurable via the Rossiter-McLaughlin effect. After one year, gravitational wave emission shifts the time of eclipses by 5.5 s, but tidal interactions cause the orbit to shrink more rapidly, changing the time by up to an additional 0.3 s after a year. Future eclipse timing measurements may therefore infer the degree of tidal locking.

  9. Adsorption of desflurane by the silica gel filters in breathing circuits: an in vitro study

    PubMed Central

    Song, Seok Young; Lim, Bo Reum

    2015-01-01

    Background During general anesthesia, a heated breathing circuit (HBC) is used to replace the heat and moisture exchange function of the upper airway. One HBC uses an air dryer filter that employs silica gel (SG) as a desiccant. SG is capable of adsorbing many organic compounds. Therefore, we undertook an in vitro study of the adsorption of desflurane by SG filters. Methods An HBC was connected to an anesthesia machine, and a test lung was connected to the circuit. The test lung was mechanically ventilated with 2 or 4 L/min of fresh gas flow, with and without the air dryer filter. Desflurane was administered at a 6 vol% on the vaporizer dial setting. The experiment was repeated 15 times in each group. The end-tidal concentrations were measured during the experiments. The air dryer filter weights were measured before and after the experiments, and the times required to achieve the specific end-tidal desflurane concentrations were determined. Results Significant differences in the end-tidal concentrations of desflurane were observed between the control and filter groups (P < 0.001). The filter weights increased significantly after the experiments (P < 0.001). The times required to achieve the same end-tidal desflurane concentrations were different with the application of the air dryer filter (P < 0.001). Conclusions The adsorption of desflurane with the use of an air dryer filter was verified in this in vitro study. Careful attention is needed when using air dryer gel filters during general anesthesia. PMID:26045931

  10. Fitting orbits to tidal streams

    NASA Astrophysics Data System (ADS)

    Binney, James

    2008-05-01

    Recent years have seen the discovery of many tidal streams through the Galaxy. Relatively straightforward observations of a stream allow one to deduce three phase-space coordinates of an orbit. An algorithm is presented that reconstructs the missing phase-space coordinates from these data. The reconstruction starts from assumed values of the Galactic potential and a distance to one point on the orbit, but with noise-free data the condition that energy be conserved on the orbit enables one to reject incorrect assumptions. The performance of the algorithm is investigated when errors are added to the input data that are comparable to those in published data for the streams of Pal 5. It is found that the algorithm returns distances and proper motions that are accurate to of the order of 1 per cent, and enables one to reject quite resonable but incorrect trial potentials. In practical applications, it will be important to minimize errors in the imput data, and there is considerable scope for doing this.

  11. The fast exercise drive to breathe.

    PubMed

    Duffin, James

    2014-02-01

    This paper presents a personal view of research into the exercise drive to breathe that can be observed to act immediately to increase breathing at the start of rhythmic exercise. It is based on a talk given at the Experimental Biology 2013 meeting in a session entitled 'Recent advances in understanding mechanisms regulating breathing during exercise'. This drive to breathe has its origin in a combination of central command, whereby voluntary motor commands to the exercising muscles produce a concurrent respiratory drive, and afferent feedback, whereby afferent information from the exercising muscles affects breathing. The drive at the start and end of rhythmic exercise is proportional to limb movement frequency, and its magnitude decays as exercise continues so that the immediate decrease of ventilation at the end of exercise is about 60% of the immediate increase at the start. With such evidence for the effect of this fast drive to breathe at the start and end of rhythmic exercise, its existence during exercise is hypothesised. Experiments to test this hypothesis have, however, provided debatable evidence. A fast drive to breathe during both ramp and sine wave changes in treadmill exercise speed and grade appears to be present in some individuals, but is not as evident in the general population. Recent sine-wave cycling experiments show that when cadence is varied sinusoidally the ventilation response lags by about 10 s, whereas when pedal loading is varied ventilation lags by about 30 s. It therefore appears that limb movement frequency is effective in influencing ventilation during exercise as well as at the start and end of exercise. PMID:23940383

  12. The fast exercise drive to breathe.

    PubMed

    Duffin, James

    2014-02-01

    This paper presents a personal view of research into the exercise drive to breathe that can be observed to act immediately to increase breathing at the start of rhythmic exercise. It is based on a talk given at the Experimental Biology 2013 meeting in a session entitled 'Recent advances in understanding mechanisms regulating breathing during exercise'. This drive to breathe has its origin in a combination of central command, whereby voluntary motor commands to the exercising muscles produce a concurrent respiratory drive, and afferent feedback, whereby afferent information from the exercising muscles affects breathing. The drive at the start and end of rhythmic exercise is proportional to limb movement frequency, and its magnitude decays as exercise continues so that the immediate decrease of ventilation at the end of exercise is about 60% of the immediate increase at the start. With such evidence for the effect of this fast drive to breathe at the start and end of rhythmic exercise, its existence during exercise is hypothesised. Experiments to test this hypothesis have, however, provided debatable evidence. A fast drive to breathe during both ramp and sine wave changes in treadmill exercise speed and grade appears to be present in some individuals, but is not as evident in the general population. Recent sine-wave cycling experiments show that when cadence is varied sinusoidally the ventilation response lags by about 10 s, whereas when pedal loading is varied ventilation lags by about 30 s. It therefore appears that limb movement frequency is effective in influencing ventilation during exercise as well as at the start and end of exercise.

  13. The fast exercise drive to breathe

    PubMed Central

    Duffin, James

    2014-01-01

    This paper presents a personal view of research into the exercise drive to breathe that can be observed to act immediately to increase breathing at the start of rhythmic exercise. It is based on a talk given at the Experimental Biology 2013 meeting in a session entitled ‘Recent advances in understanding mechanisms regulating breathing during exercise’. This drive to breathe has its origin in a combination of central command, whereby voluntary motor commands to the exercising muscles produce a concurrent respiratory drive, and afferent feedback, whereby afferent information from the exercising muscles affects breathing. The drive at the start and end of rhythmic exercise is proportional to limb movement frequency, and its magnitude decays as exercise continues so that the immediate decrease of ventilation at the end of exercise is about 60% of the immediate increase at the start. With such evidence for the effect of this fast drive to breathe at the start and end of rhythmic exercise, its existence during exercise is hypothesised. Experiments to test this hypothesis have, however, provided debatable evidence. A fast drive to breathe during both ramp and sine wave changes in treadmill exercise speed and grade appears to be present in some individuals, but is not as evident in the general population. Recent sine-wave cycling experiments show that when cadence is varied sinusoidally the ventilation response lags by about 10 s, whereas when pedal loading is varied ventilation lags by about 30 s. It therefore appears that limb movement frequency is effective in influencing ventilation during exercise as well as at the start and end of exercise. PMID:23940383

  14. Exercise carbon dioxide (CO2) retention with inhaled CO2 and breathing resistance.

    PubMed

    Shykoff, Barbara E; Warkander, Dan E

    2012-01-01

    Combined effects on respiratory minute ventilation (VE)--and thus, on end-tidal carbon dioxide partial pressure (P(ET)CO2)--of breathing resistance and elevated inspired carbon dioxide (CO2) had not been determined during heavy exercise. In this Institutional Review Board-approved, dry, sea-level study, 12 subjects in each of three phases exercised to exhaustion at 85% peak oxygen uptake while V(E) and P(ET)CO2 were measured. Participants inhaled 0%, 1%, 2% or 3% CO2 in air, or 0% or 2% CO2 in oxygen, with or without breathing resistance, mimicking the U.S. Navy's MK 16 rebreather underwater breathing apparatus (UBA). Compared to air baseline (0% inspired CO2 in air without resistance): (1) Oxygen decreased baseline V(E) (p < 0.01); (2) Inspired CO2 increased V(E) and P(ET)CO2 (p < 0.01); (3) Resistance decreased V(E) (p < 0.01); (4) Inspired CO2 with resistance elevated P(ET)CO2 (p < 0.01). In air, V(E) did not change from that with resistance alone. In oxygen, V(E) returned to oxygen baseline. End-exercise P(ET)CO2 exceeded 60 Torr (8.0 kPa) in three tests. Subjects identified hypercapnia poorly. Results support dual optimization of arterial carbon dioxide partial pressure and respiratory effort. Because elevated CO2 may not increase V(E) if breathing resistance and VE are high, rebreather UBA safety requires very low inspired CO2.

  15. Single-breath diffusing capacity of NO independent of inspiratory NO concentration in rabbits.

    PubMed

    Heller, H; Schuster, K D

    1997-12-01

    Pulmonary diffusing capacity of NO (DLNO) was determined by performing single-breath experiments on six anesthetized paralyzed supine rabbits, applying inspiratory concentrations of NO (FINO) within a range of 10 parts per million (ppm) < or = FINO < or = 800 ppm. Starting from residual volume, the rabbit lungs were inflated by 50 ml of a NO-nitrogen-containing indicator gas mixture. Breath-holding time was set at 0.1, 1, 3, 5, and 7 s. Alveolar partial pressure of NO was determined by analyzing the end-tidal portion from expirates, with the use of respiratory mass spectrometry. In the six animals, pulmonary diffusing capacity of NO averaged DLNO = 1.92 +/- 0.21 ml.mmHg-1.min-1 (mean +/- SD value). Despite extreme variations in FINO, we found very similar DLNO values, and in three rabbits we found identical values even at such different FINO levels of 80 ppm or 500, 20, or 200 ppm as well as 10 or 800 ppm. There was also no dependence of DLNO on the respective duration of the single-breath maneuvers. In addition, the time course of NO removal from alveolar space was independent of applied FINO levels. These results suggest that DLNO determinations are neither affected by chemical reactions of NO in alveolar gas phase as well as in lung tissue nor biased by endogenous release of NO from pulmonary tissue. It is our conclusion that the single-breath diffusing capacity of NO is able to provide a measure of alveolar-capillary gas conductance that is not influenced by the biochemical reactions of NO.

  16. Metabolic and Ventilatory Changes During and After High-Frequency Yoga Breathing

    PubMed Central

    Telles, Shirley; Singh, Nilkamal; Balkrishna, Acharya

    2015-01-01

    Background Practicing high-frequency yoga breathing (HFYB) induced a hypermetabolic state in a single subject during the practice but the effect has not been studied in multiple practitioners. Material/Methods Healthy male volunteers (n=47, group mean age ±S.D., 23.2±4.1 years) were recruited as an experimental group and another twenty volunteers were recruited as a control group. The experimental group practiced either HFYB (Breath rate 1.0 Hz) or breath awareness (BAW) on two separate days. The sequence was reversed for alternate participants. The control group was assessed under similar conditions while sitting at ease. The breath rate (RR), tidal volume (VT), ventilation (VE), VO2, VCO2, arterial PCO2 and energy expenditure (EE Kcal/day) were assessed for 35 minutes using an open circuit oxygen consumption analyzer. The assessment period was divided into before, during and after conditions. Repeated measures analyses of variance (ANOVA) were used to compare data recorded during and after the two practices with data recorded before. Before-After comparisons in the control group were with paired t-tests. Results The most relevant significant changes were increases in VE, VO2, VCO2 and EE during HFYB, while the same variables decreased during the control period. However after HFYB there was no change in VO2 or EE, although VE decreased as it did after the control period. Conclusions HFYB induces a hypermetabolic state for the duration of the practice which returns to baseline after HFYB suggesting a possible application for HFYB in hypometabolic states. PMID:26270968

  17. Ventilatory efficiency and breathing pattern in world-class cyclists: A three-year observational study.

    PubMed

    Salazar-Martínez, Eduardo; Terrados, Nicolás; Burtscher, Martin; Santalla, Alfredo; Naranjo Orellana, José

    2016-07-15

    The purpose of this three-year observational study was to analyze the ventilatory efficiency and breathing pattern in world-class professional cyclists. Twelve athletes (22.61±3.8years; 177.38±5.5cm; 68.96±5.5kg and VO2max 75.51±3.3mLkg(-1)min(-1)) were analyzed retrospectively. For each subject, respiratory and performance variables were recorded during incremental spiroergometry: oxygen uptake (VO2), carbon dioxide output (VCO2), pulmonary ventilation (VE), tidal volume (Vt), breathing frequency (fR), driving (Vt/Ti), timing (Ti/Ttot), peak power output (PPO) and maximum oxygen uptake (VO2max). Ventilatory efficiency (VE/VCO2 slope) was calculated from the beginning of exercise testing to the second ventilatory threshold (VT2). The VE/VCO2 slope was unaffected during the study period (24.63±3.07; 23.61±2:79; 24:89±2:61) with a low effect size (ES=0.04). The PPO improved significantly in the third year (365±33.74; 386.36±32.33; 415.00±24.15) (p<0.05). The breathing pattern variables, Vt/Ti and Ti/Ttot, did not change significantly over the three year period (ES=0.00; ES=0.03 respectively). These findings suggest that changes in cycling performance in world-class professional cyclists do not modify breathing variables related to the control of ventilatory efficiency.

  18. Metabolic and Ventilatory Changes During and After High-Frequency Yoga Breathing.

    PubMed

    Telles, Shirley; Singh, Nilkamal; Balkrishna, Acharya

    2015-01-01

    BACKGROUND Practicing high-frequency yoga breathing (HFYB) induced a hypermetabolic state in a single subject during the practice but the effect has not been studied in multiple practitioners. MATERIAL AND METHODS Healthy male volunteers (n=47, group mean age ± S.D., 23.2 ± 4.1 years) were recruited as an experimental group and another twenty volunteers were recruited as a control group. The experimental group practiced either HFYB (Breath rate 1.0 Hz) or breath awareness (BAW) on two separate days. The sequence was reversed for alternate participants. The control group was assessed under similar conditions while sitting at ease. The breath rate (RR), tidal volume (VT), ventilation (VE), VO2, VCO2, arterial PCO2 and energy expenditure (EE Kcal/day) were assessed for 35 minutes using an open circuit oxygen consumption analyzer. The assessment period was divided into before, during and after conditions. Repeated measures analyses of variance (ANOVA) were used to compare data recorded during and after the two practices with data recorded before. Before-After comparisons in the control group were with paired t-tests. RESULTS The most relevant significant changes were increases in VE, VO2, VCO2 and EE during HFYB, while the same variables decreased during the control period. However after HFYB there was no change in VO2 or EE, although VE decreased as it did after the control period. CONCLUSIONS HFYB induces a hypermetabolic state for the duration of the practice which returns to baseline after HFYB suggesting a possible application for HFYB in hypometabolic states. PMID:26270968

  19. Ventilatory efficiency and breathing pattern in world-class cyclists: A three-year observational study.

    PubMed

    Salazar-Martínez, Eduardo; Terrados, Nicolás; Burtscher, Martin; Santalla, Alfredo; Naranjo Orellana, José

    2016-07-15

    The purpose of this three-year observational study was to analyze the ventilatory efficiency and breathing pattern in world-class professional cyclists. Twelve athletes (22.61±3.8years; 177.38±5.5cm; 68.96±5.5kg and VO2max 75.51±3.3mLkg(-1)min(-1)) were analyzed retrospectively. For each subject, respiratory and performance variables were recorded during incremental spiroergometry: oxygen uptake (VO2), carbon dioxide output (VCO2), pulmonary ventilation (VE), tidal volume (Vt), breathing frequency (fR), driving (Vt/Ti), timing (Ti/Ttot), peak power output (PPO) and maximum oxygen uptake (VO2max). Ventilatory efficiency (VE/VCO2 slope) was calculated from the beginning of exercise testing to the second ventilatory threshold (VT2). The VE/VCO2 slope was unaffected during the study period (24.63±3.07; 23.61±2:79; 24:89±2:61) with a low effect size (ES=0.04). The PPO improved significantly in the third year (365±33.74; 386.36±32.33; 415.00±24.15) (p<0.05). The breathing pattern variables, Vt/Ti and Ti/Ttot, did not change significantly over the three year period (ES=0.00; ES=0.03 respectively). These findings suggest that changes in cycling performance in world-class professional cyclists do not modify breathing variables related to the control of ventilatory efficiency. PMID:27083403

  20. Hydrodynamics and sediment suspension in shallow tidal channels intersecting a tidal flat

    NASA Astrophysics Data System (ADS)

    Pieterse, Aline; Puleo, Jack A.; McKenna, Thomas E.

    2016-05-01

    A field study was conducted on a tidal flat intersected by small tidal channels (depth <0.1 m, width <2 m) within a tidal marsh. Data were collected in the channels, and on the adjacent tidal flat that encompasses approximately 1600 m2 in planform area. Hydrodynamic processes and sediment suspension between the channels and adjacent flat were compared. Shear stress and turbulent kinetic energy were computed from high frequency velocity measurements. Maximum water depth at the field site varied from 0.11 m during the lowest neap high tide to 0.58 m during a storm event. In the channel intersecting the tidal flat, the shear stress, turbulence and along-channel velocity were ebb dominant; e.g. 0.33 m/s peak velocity for ebb compared to 0.19 m/s peak velocity for flood. Distinct pulses in velocity occurred when the water level was near the tidal flat level. The velocity pulse during flood tide occurred at a higher water level than during ebb tide. No corresponding velocity pulse on the tidal flat was observed. Sediment concentrations peaked at the beginning and end of each tidal cycle, and often had a secondary peak close to high tide, assumed to be related to sediment advection. The influence of wind waves on bed shear stress and sediment suspension was negligible. Water levels were elevated during a storm event such that the tidal flat remained inundated for 4 tidal cycles. The water did not drain from the tidal flat into the channels during the storm, and no velocity pulses occurred. Along-channel velocities, turbulent kinetic energy, and shear stresses were therefore smaller in the channels during storm conditions than during non-storm conditions.

  1. Factors Influencing Continuous Breath Signal in Intubated and Mechanically-Ventilated Intensive Care Unit Patients Measured by an Electronic Nose

    PubMed Central

    Leopold, Jan Hendrik; Abu-Hanna, Ameen; Colombo, Camilla; Sterk, Peter J.; Schultz, Marcus J.; Bos, Lieuwe D. J.

    2016-01-01

    Introduction: Continuous breath analysis by electronic nose (eNose) technology in the intensive care unit (ICU) may be useful in monitoring (patho) physiological changes. However, the application of breath monitoring in a non-controlled clinical setting introduces noise into the data. We hypothesized that the sensor signal is influenced by: (1) humidity in the side-stream; (2) patient-ventilator disconnections and the nebulization of medication; and (3) changes in ventilator settings and the amount of exhaled CO2. We aimed to explore whether the aforementioned factors introduce noise into the signal, and discuss several approaches to reduce this noise. Methods: Study in mechanically-ventilated ICU patients. Exhaled breath was monitored using a continuous eNose with metal oxide sensors. Linear (mixed) models were used to study hypothesized associations. Results: In total, 1251 h of eNose data were collected. First, the initial 15 min of the signal was discarded. There was a negative association between humidity and Sensor 1 (Fixed-effect β: −0.05 ± 0.002) and a positive association with Sensors 2–4 (Fixed-effect β: 0.12 ± 0.001); the signal was corrected for this noise. Outliers were most likely due to noise and therefore removed. Sensor values were positively associated with end-tidal CO2, tidal volume and the pressure variables. The signal was corrected for changes in these ventilator variables after which the associations disappeared. Conclusion: Variations in humidity, ventilator disconnections, nebulization of medication and changes of ventilator settings indeed influenced exhaled breath signals measured in ventilated patients by continuous eNose analysis. We discussed several approaches to reduce the effects of these noise inducing variables. PMID:27556467

  2. Evolution and stability of tidal river bifurcations

    NASA Astrophysics Data System (ADS)

    Kleinhans, M. G.

    2011-12-01

    At bifurcations, water and sediment are partitioned, so that long-term evolution of fluvial and deltaic channels is determined by the bifurcation stability. Recent work in fluvial environments showed that bifurcations are commonly unstable so that avulsion results. For tidal rivers it could be argued that the discharge fluctuation enhances transport so that it simply closes of faster than in steady flow, but it could also be argued that tidal phase differences between the bifurcates cause a residual flow that counteracts the closing trend and keeps both bifurcates open. A physics-based numerical model (Delft3D) was used to model fixed-bank fork-shaped bifurcations with and without tides, and with short and long length relative to tidal wavelength. In all cases the bifurcations remained as unstable as without tides and ended invariably in avulsion. Tidal bifurcations unbalanced more rapidly than fluvial bifurcations, because of the increased ebb current and nonlinearity of sediment transport. On the other hand, discharge partitioning at the final bifurcation was much less asymmetrical with tides than without. Tidal wave deformation and production of higher harmonics in the longer channels affected sediment partitioning in the unstable phase but seems to have no effect on equilibrium morphology. Significant phase differences between the bifurcates caused a tidal floss effect, which scoured the bifurcation. In conclusion, symmetrical bifurcations affected by tides are unstable, but their final equilibrium is more symmetrical than without tides unless bifurcates have significant tidal phase differences. Furthermore I modelled growing deltas with self-formed distributary channels with and without cohesive sediment and with and without tides. Here, tides cause the flow to be more focussed in fewer and larger channels, whilst the few bifurcations are relatively stable. Combined fluvial discharge and tidal ebb flow in the channels transports more sediment than in fluvial

  3. Sudarshan kriya yoga: Breathing for health.

    PubMed

    Zope, Sameer A; Zope, Rakesh A

    2013-01-01

    Breathing techniques are regularly recommended for relaxation, stress management, control of psychophysiological states, and to improve organ function. Yogic breathing, defined as a manipulation of breath movement, has been shown to positively affect immune function, autonomic nervous system imbalances, and psychological or stress-related disorders. The aim of this study was to assess and provide a comprehensive review of the physiological mechanisms, the mind-body connection, and the benefits of Sudarshan Kriya Yoga (SKY) in a wide range of clinical conditions. Various online databases searched were Medline, Psychinfo, EMBASE, and Google Scholar. All the results were carefully screened and articles on SKY were selected. The references from these articles were checked to find any other potentially relevant articles. SKY, a unique yogic breathing practice, involves several types of cyclical breathing patterns, ranging from slow and calming to rapid and stimulating. There is mounting evidence to suggest that SKY can be a beneficial, low-risk, low-cost adjunct to the treatment of stress, anxiety, post-traumatic stress disorder, depression, stress-related medical illnesses, substance abuse, and rehabilitation of criminal offenders. PMID:23440614

  4. Breath suspension during the transcendental meditation technique.

    PubMed

    Farrow, J T; Hebert, J R

    1982-05-01

    We observed, over four independent experiments, 565 criterion-meeting episodes of breath suspension in 40 subjects practicing the Transcendental Mediation technique (TM), a simple mental technique involving no breath control procedures. The frequency and length of these breath suspension episodes were substantially and significantly greater for TM subjects than for control subjects relaxing with eyes closed. Voluntary control of respiration was most probably eliminated as an explanation of ths phenomenon by the experimental design and by the use of a variety of nonintrusive respiration transducers, including a two-channel magnetometer, an indirect but accurate means of monitoring respiration. Many TM subjects report experience of a completely quiescent mental state characterized by maintained awareness in the absence of thought. Eleven TM subjects were instructed to press an event mark button after each episode of this pure consciousness experience. The temporal distribution of button presses was significantly related (p less than 10(-10) to the distribution of breath suspension episodes, indicating that breath suspension is a physiological correlate of some, but not all, episodes of the pure consciousness experience. In an extensive study of a single advanced mediator, pure consciousness experiences were also associated with reduced heart rate; high basal skin resistance; stable phasic skin resistance; markedly reduced mean respiration rate, mean minute ventilation and mean metabolic rate; and statistically consistent changes in EEG power and EEG coherence (an indicator of long-range spatial order in the nervous system).

  5. Breath tests in diagnosis of pulmonary tuberculosis.

    PubMed

    Cheepsattayakorn, Attapon; Cheepsattayakorn, Ruangrong

    2014-01-01

    Since the time of Hippocrates, physicians have known that the odour of human breath can provide clues to diagnosis. In the past, hydrogen peroxide which is a marker of inflammatory diseases and oxidative stress was the most studied substance in the exhaled breath which was detectable in the liquid that obtained by condensing or cooling. The advantages of breath analysis are that it is convenient, non-invasive, and could be performed with children as well as mechanically ventilated patients. Today, exhaled nitric oxide has been studied extensively, especially in relation to asthma. More than a thousand different volatile organic compounds have been observed in low concentrations in normal human breath. Alkanes and methylalkanes have been increasingly used by physicians as a novel method to diagnose many diseases without discomforts of invasive procedures. Although the limitations of measurement of exhaled nitric oxide in direct diagnosis of infectious pulmonary TB, it may have potential development as a cost-effective replacement of chest radiological examination in screening algorithms. None of the individual exhaled volatile organic compound alone is specific for disease. Exhaled breath analysis techniques may be available to diagnose and monitor the diseases in home setting when their sensitivity and specificity are expected to improve in the future. Here, we also discussed some patents related to the topic. PMID:25185981

  6. Pulse Ejection Presentation System Synchronized with Breathing

    NASA Astrophysics Data System (ADS)

    Kadowaki, Ami; Sato, Junta; Ohtsu, Kaori; Bannai, Yuichi; Okada, Kenichi

    Trials on transmission of olfactory information together with audio/visual information are currently being conducted in the field of multimedia. However, continuous emission of scents in high concentration creates problems of human adaptation and remnant odors in air. To overcome such problems we developed an olfactory display in conjunction with Canon Inc. This display has high emission control in the ink-jet so that it can provide stable pulse emission of scents. Humans catch a scent when they breathe in and inhale smell molecules in air. Therefore, it is important that the timing of scent presentation is synchronized with human breathing. We also developed a breath sensor which detects human inspiration. In this study, we combined the olfactory display with the breath sensor to make a pulse ejection presentation system synchronized the breath. The experimental evaluation showed that the system had more than 90 percent of detection rate. Another evaluation was held at KEIO TECHNO-MALL 2007. From questionnaire results of the participants, we found that the system made the user feel continuous sense of smell avoiding adaptation. It is expected that our system enables olfactory information to be synchronized with audio/visual information in arbitrary duration at any time.

  7. Sudarshan kriya yoga: Breathing for health

    PubMed Central

    Zope, Sameer A.; Zope, Rakesh A

    2013-01-01

    Breathing techniques are regularly recommended for relaxation, stress management, control of psychophysiological states, and to improve organ function. Yogic breathing, defined as a manipulation of breath movement, has been shown to positively affect immune function, autonomic nervous system imbalances, and psychological or stress-related disorders. The aim of this study was to assess and provide a comprehensive review of the physiological mechanisms, the mind–body connection, and the benefits of Sudarshan Kriya Yoga (SKY) in a wide range of clinical conditions. Various online databases searched were Medline, Psychinfo, EMBASE, and Google Scholar. All the results were carefully screened and articles on SKY were selected. The references from these articles were checked to find any other potentially relevant articles. SKY, a unique yogic breathing practice, involves several types of cyclical breathing patterns, ranging from slow and calming to rapid and stimulating. There is mounting evidence to suggest that SKY can be a beneficial, low-risk, low-cost adjunct to the treatment of stress, anxiety, post-traumatic stress disorder, depression, stress-related medical illnesses, substance abuse, and rehabilitation of criminal offenders. PMID:23440614

  8. Plant distributions along salinity and tidal gradients in Oregon tidal marshes

    EPA Science Inventory

    Accurately modeling climate change effects on tidal marshes in the Pacific Northwest requires understanding how plant assemblages and species are presently distributed along gradients of salinity and tidal inundation. We outline on-going field efforts by the EPA and USGS to dete...

  9. Biogeomorphology of tidal landforms: physical and biological processes shaping the tidal landscape

    NASA Astrophysics Data System (ADS)

    Marani, M.; D'Alpaos, A.; Da Lio, C.

    2011-12-01

    The equilibrium states and transient dynamics of tidal landforms are the result of many concurring physical and biological forcings, such as tidal range, wind climate, sediment supply, vegetation and microphytobenthos development, and rates of relative sea level rise (RSLR). A 0D model of the coupled elevation-vegetation dynamics is used to explore the relative role of the physical and biological factors shaping these systems. We find that salt marshes exposed to large tidal ranges are more stable, and therefore more resilient to increasing rates of RSLR, than marshes subjected to low tidal ranges and that subtidal platforms in macrotidal systems are less exposed to wind-induced erosion processes than their counterparts in systems with smaller tidal fluctuations. Notably, we find that vegetation crucially affects both the equilibrium marsh elevation, through dissipation of wind waves and organic accumulation, and marsh resilience to accelerations in RSLR rates, important differences being associated with different vegetation types. Furthermore, our results show that the existence and stability of equilibrium states fundamentally depend on the local wind and tidal regime, even within the same tidal system. Finally, we propose a modelling framework to study how biological evolution lead to the emergence of tidal landforms as we know them.

  10. A Review of Tidal Salt Marsh Morphodynamics

    NASA Astrophysics Data System (ADS)

    Friedrichs, C. T.; Perry, J. E.

    2001-05-01

    We now understand that, morphologically, natural tidal marshes are generally near or progressing rapidly toward dynamic equilibrium with sediment supply, vegetative growth and relative sea level, rather than far out of equilibrium on a slow evolution toward geologic maturity. The last fifteen years have been marked by major advances in the observation of sedimentation and accretion patterns in tidal salt marshes which reinforce the above interpretation. This paper reviews and synthesizes advances since the late 1980s in our understanding of tidal salt marsh morphodynamics. Recent work has shown that allochthonous deposition patterns on the marsh are controlled primarily by source concentration, distance from that source, and duration of inundation (in turn determined by marsh elevation). Because deposition is proportional to inundation period, inorganic accretion tends to increase or decrease with accelerated or decelerated sea level rise, allowing the accretion rate to similarly fluctuate. Feedback between proximity to sediment source and duration of inundation causes relatively uniform accretion to be characterized by highest marsh elevations adjacent to tidal creeks. Since physical stress on vegetation increases with inundation, plant density and accretion of organic matter is reduced as inundation period increases, a pattern opposite to allochthonous deposition. Among systems dominated by allochthonous sediment, microtidal marshes are more reliant on storm and flood sedimentation and horizontally expand and retreat more quickly than macrotidal marshes, while the latter are more likely to persist during periods of accelerated sea level rise. The density, width and depth of salt marsh creeks all increase with increased tidal prism. Along barrier coastlines, greater tidal range is associated with more frequent inlet spacing, shallower channels, flood-dominance, and higher marsh elevation at equilibrium. Smaller tidal range results in greater inlet spacing, deeper

  11. Monitoring Jupiter's Atmosphere for Tidal Oscillations

    NASA Astrophysics Data System (ADS)

    Houben, H.; Mosqueira, I.; Showman, A.; Young, R. E.

    2003-12-01

    Tidal dissipation in Jupiter is the ultimate source of the energy that powers Io's volcanism and may also be an important cause of heating in Europa and Ganymede. However, the mechanism of jovian tidal dissipation is still unknown. In general, there are two possibilities that can work in a fluid planet: 1) some viscous process in the interior of the planet (although eddy viscosity due to convective overturning can be excluded because of the large mismatch between the tidal period and the convective eddy timescale); or 2) the generation of inertia-gravity waves (a natural consequence of tidal forcing in any stably stratified fluid) that propagate to the upper atmosphere before breaking. Our calculations rule out the possibility that a stable, resonant, ducting layer in the atmosphere or outer envelope of Jupiter would result in large wave amplitudes and dissipate enough energy to account for a longterm average tidal dissipation factor (Q) of 105. But, we cannot exclude the possibility that a stable layer (perhaps due to composition gradients) in the deep interior would have this effect. The resulting energy flux ( ˜ 1021 erg/s) would be an important factor in the thermospheric heat balance. Thus, by monitoring Jupiter's atmosphere to determine the amplitude of the tidal wave response, JIMO would contribute to the understanding of the longterm orbital and thermal evolution of the Galilean satellites, while also shedding light on Jupiter's interior structure and upper atmospheric heat balance. Even a negative result would be valuable. Although global jovian atmospheric oscillations have been difficult to observe, the fact that we know the tidal frequencies and wavenumbers exactly will make it possible to add even random or opportunistic observations in phase to enhance the desired signal. We estimate that the waves will have a temperature amplitude less than 1 K, but a horizontal wind amplitude of up to 10 m/s at the 100 mbar level of the atmosphere.

  12. Technologies for Clinical Diagnosis Using Expired Human Breath Analysis.

    PubMed

    Mathew, Thalakkotur Lazar; Pownraj, Prabhahari; Abdulla, Sukhananazerin; Pullithadathil, Biji

    2015-01-01

    This review elucidates the technologies in the field of exhaled breath analysis. Exhaled breath gas analysis offers an inexpensive, noninvasive and rapid method for detecting a large number of compounds under various conditions for health and disease states. There are various techniques to analyze some exhaled breath gases, including spectrometry, gas chromatography and spectroscopy. This review places emphasis on some of the critical biomarkers present in exhaled human breath, and its related effects. Additionally, various medical monitoring techniques used for breath analysis have been discussed. It also includes the current scenario of breath analysis with nanotechnology-oriented techniques. PMID:26854142

  13. Technologies for Clinical Diagnosis Using Expired Human Breath Analysis

    PubMed Central

    Mathew, Thalakkotur Lazar; Pownraj, Prabhahari; Abdulla, Sukhananazerin; Pullithadathil, Biji

    2015-01-01

    This review elucidates the technologies in the field of exhaled breath analysis. Exhaled breath gas analysis offers an inexpensive, noninvasive and rapid method for detecting a large number of compounds under various conditions for health and disease states. There are various techniques to analyze some exhaled breath gases, including spectrometry, gas chromatography and spectroscopy. This review places emphasis on some of the critical biomarkers present in exhaled human breath, and its related effects. Additionally, various medical monitoring techniques used for breath analysis have been discussed. It also includes the current scenario of breath analysis with nanotechnology-oriented techniques. PMID:26854142

  14. Sleep and Breathing at High Altitude.

    PubMed

    Wickramasinghe, Himanshu; Anholm, James D.

    1999-01-01

    Sleep at high altitude is characterized by poor subjective quality, increased awakenings, frequent brief arousals, marked nocturnal hypoxemia, and periodic breathing. A change in sleep architecture with an increase in light sleep and decreasing slow-wave and REM sleep have been demonstrated. Periodic breathing with central apnea is almost universally seen amongst sojourners to high altitude, although it is far less common in long-standing high altitude dwellers. Hypobaric hypoxia in concert with periodic breathing appears to be the principal cause of sleep disruption at altitude. Increased sleep fragmentation accounts for the poor sleep quality and may account for some of the worsened daytime performance at high altitude. Hypoxic sleep disruption contributes to the symptoms of acute mountain sickness. Hypoxemia at high altitude is most severe during sleep. Acetazolamide improves sleep, AMS symptoms, and hypoxemia at high altitude. Low doses of a short acting benzodiazepine (temazepam) may also be useful in improving sleep in high altitude. PMID:11898114

  15. Effect of dietary turmeric on breath hydrogen.

    PubMed

    Shimouchi, Akito; Nose, Kazutoshi; Takaoka, Motoko; Hayashi, Hiroko; Kondo, Takaharu

    2009-08-01

    Turmeric is widely used in Indian cuisine. The main constituents of turmeric are curcumin and its analogues, which are well-known antioxidant compounds. In the present study, we hypothesized that turmeric in curry might increase bowel motility and activate hydrogen-producing bacterial flora in the colon, thereby increasing the concentration of breath hydrogen. Eight healthy subjects fasted for 12 h and ingested curry and rice with or without turmeric (turmeric knockout curry). Breath-hydrogen concentrations were analyzed every 15 min for 6 h by gas chromatography with a semiconductor detector. Curry with turmeric significantly increased the area under the curve of breath hydrogen and shortened small-bowel transit time, compared with curry not containing turmeric. These results suggested that dietary turmeric activated bowel motility and carbohydrate colonic fermentation. PMID:19034660

  16. Decompression sickness following breath-hold diving.

    PubMed

    Schipke, J D; Gams, E; Kallweit, Oliver

    2006-01-01

    Despite convincing evidence of a relationship between breath-hold diving and decompression sickness (DCS), the causal connection is only slowly being accepted. Only the more recent textbooks have acknowledged the risks of repetitive breath-hold diving. We compare four groups of breath-hold divers: (1) Japanese and Korean amas and other divers from the Pacific area, (2) instructors at naval training facilities, (3) spear fishers, and (4) free-dive athletes. While the number of amas is likely decreasing, and Scandinavian Navy training facilities recorded only a few accidents, the number of spear fishers suffering accidents is on the rise, in particular during championships or using scooters. Finally, national and international associations (e.g., International Association of Free Drives [IAFD] or Association Internationale pour Le Developpment De L'Apnee [AIDA]) promote free-diving championships including deep diving categories such as constant weight, variable weight, and no limit. A number of free-diving athletes, training for or participating in competitions, are increasingly accident prone as the world record is presently set at a depth of 171 m. This review presents data found after searching Medline and ISI Web of Science and using appropriate Internet search engines (e.g., Google). We report some 90 cases in which DCS occurred after repetitive breath-hold dives. Even today, the risk of suffering from DCS after repetitive breath-hold diving is often not acknowledged. We strongly suggest that breath-hold divers and their advisors and physicians be made aware of the possibility of DCS and of the appropriate therapeutic measures to be taken when DCS is suspected. Because the risk of suffering from DCS increases depending on depth, bottom time, rate of ascent, and duration of surface intervals, some approaches to assess the risks are presented. Regrettably, none of these approaches is widely accepted. We propose therefore the development of easily manageable

  17. Electrospray ionization of volatiles in breath

    NASA Astrophysics Data System (ADS)

    Martínez-Lozano, P.; de La Mora, J. Fernández

    2007-08-01

    Recent work by Zenobi and colleagues [H. Chen, A. Wortmann, W. Zhang, R. Zenobi, Angew. Chem. Int. Ed. 46 (2007) 580] reports that human breath charged by contact with an electrospray (ES) cloud yields many mass peaks of species such as urea, glucose, and other ions, some with molecular weights above 1000 Da. All these species are presumed to be involatile, and to originate from breath aerosols by so-called extractive electrospray ionization EESI [H. Chen, A. Venter, R.G. Cooks, Chem. Commun. (2006) 2042]. However, prior work by Fenn and colleagues [C.M. Whitehouse, F. Levin, C.K. Meng, J.B. Fenn, Proceedings of the 34th ASMS Conference on Mass Spectrometry and Allied Topics, Denver, 1986 p. 507; S. Fuerstenau, P. Kiselev, J.B. Fenn, Proceedings of the 47th ASMS Conference on Mass Spectrometry, 1999, Dallas, TX, 1999] and by Hill and colleagues [C. Wu, W.F. Siems, H.H. Hill Jr., Anal. Chem. 72 (2000) 396] have reported the ability of electrospray drops to ionize a variety of low vapor pressure substances directly from the gas phase, without an apparent need for the vapor to be brought into the charging ES in aerosol form. The Ph.D. Thesis of Martínez-Lozano [P. Martínez-Lozano Sinués, Ph.D. Thesis, Department of Thermal and Fluid Engineering, University Carlos III of Madrid; April 5, 2006 (in Spanish); http://hdl.handle.net/10016/655] had also previously argued that the numerous human breath species observed via a similar ES ionization approach were in fact ionized directly from the vapor. Here, we observe that passage of the breath stream through a submicron filter does not eliminate the majority of the breath vapors seen in the absence of the filter. We conclude that direct vapor charging is the leading mechanism in breath ionization by electrospray drops, though aerosol ionization may also play a role.

  18. Tidal Distortion of Titan: Implications for Surface Features and Tidal Measurements

    NASA Astrophysics Data System (ADS)

    Sohl, F.; Hussmann, H.; Coustenis, A.; Knapmeyer, M.; Lange, C.; Solomonidou, A.; Stephan, K.; Wagner, F. W.

    2012-04-01

    Titan is unique due to its similarity to the Earth and terrestrial planets in spite of the satellite's ice-rich bulk composition. Gravitational field data acquired by the Cassini spacecraft suggest that Titan's interior is composed of a mixture of rock and ice and is only partly differentiated. Titan is tidally locked with respect to Saturn and thereby subject to periodic tidal forcing of its interior and surface. Based on interior structure models and assumptions on rheological properties of planetary materials (i.e. ice, rock, water-ammonia ocean), we compute the elastic body tide Love numbers h2, k2, and l2 in order to describe Titan's tidal response. Key parameters, e.g., tidally-induced changes of local gravity, tilt relative to the direction of gravity, and areal strain are then given by linear combinations of h2, k2, and l2. We find peak-to-peak amplitudes of tidally-induced surface displacement and tilt variation on the order of up to a few tens of metres and a few arc seconds, respectively. Based on the obtained variations of tidal parameters, we will address possible implications for morphotectonic surface features and compositional heterogeneity on Titan. In addition, we will address possible measurements of global tidal distortion by using a network of several small landed stations. Each of those would have to carry an instrument suite to monitor tidally-induced changes of local gravity, tilt relative to the direction of gravity, and areal strain at the surface of Titan. Furthermore, tidal stresses are expected to induce significant seismic activity comparable to tidally-induced quakes on the Moon, and possibly along with seismicity induced by localized cryovolcanic activity.

  19. Sleep-Disordered Breathing and Cardiac Arrhythmias.

    PubMed

    Bitter, Thomas; Fox, Henrik; Gaddam, SaiPrassad; Horstkotte, Dieter; Oldenburg, Olaf

    2015-07-01

    Over the past few years sleep-disordered breathing has been identified as an important factor in arrhythmogenesis and a potential target of therapy to prevent cardiac arrhythmias in selected patients. In this review we highlight the role of obstructive sleep apnea and Cheyne-Stokes respiration in the pathophysiology of arrhythmias, address their clinical effect in supraventricular and ventricular tachyarrhythmias, and in conduction disturbances, and address the role of current treatment options for sleep-disordered breathing in the primary and secondary prevention of arrhythmic events.

  20. Medication effects on sleep and breathing.

    PubMed

    Seda, Gilbert; Tsai, Sheila; Lee-Chiong, Teofilo

    2014-09-01

    Sleep respiration is regulated by circadian, endocrine, mechanical and chemical factors, and characterized by diminished ventilatory drive and changes in Pao2 and Paco2 thresholds. Hypoxemia and hypercapnia are more pronounced during rapid eye movement. Breathing is influenced by sleep stage and airway muscle tone. Patient factors include medical comorbidities and body habitus. Medications partially improve obstructive sleep apnea and stabilize periodic breathing at altitude. Potential adverse consequences of medications include precipitation or worsening of disorders. Risk factors for adverse medication effects include aging, medical disorders, and use of multiple medications that affect respiration.

  1. Breathing air trailer acceptance test procedure

    SciTech Connect

    Kostelnik, A.J.

    1994-09-14

    This Acceptance Test Procedure (ATP) will document compliance with the requirements of WHC-S-0251 Rev. 0 and ECNs 613530 and 606113. The equipment being tested is a Breathing Air Supply Trailer purchased as a Design and Fabrication procurement activity for use in the core sampling program. The ATP was written by the Seller and will be performed by the Seller with representatives of the Westinghouse Hanford Company witnessing the test at the Seller`s location. This test procedure is to verify that the American Bristol Industries, Inc., Model 5014-0001 low pressure Mobile Breathing Air Trailer, meets or exceeds the requirements of the Westinghouse Hanford specification.

  2. Tidal Response of Preliminary Jupiter Model

    NASA Astrophysics Data System (ADS)

    Wahl, Sean M.; Hubbard, William B.; Militzer, Burkhard

    2016-11-01

    In anticipation of improved observational data for Jupiter’s gravitational field, from the Juno spacecraft, we predict the static tidal response for a variety of Jupiter interior models based on ab initio computer simulations of hydrogen–helium mixtures. We calculate hydrostatic-equilibrium gravity terms, using the non-perturbative concentric Maclaurin Spheroid method that eliminates lengthy expansions used in the theory of figures. Our method captures terms arising from the coupled tidal and rotational perturbations, which we find to be important for a rapidly rotating planet like Jupiter. Our predicted static tidal Love number, {k}2=0.5900, is ∼10% larger than previous estimates. The value is, as expected, highly correlated with the zonal harmonic coefficient J 2, and is thus nearly constant when plausible changes are made to the interior structure while holding J 2 fixed at the observed value. We note that the predicted static k 2 might change, due to Jupiter’s dynamical response to the Galilean moons, and find reasons to argue that the change may be detectable—although we do not present here a theory of dynamical tides for highly oblate Jovian planets. An accurate model of Jupiter’s tidal response will be essential for interpreting Juno observations and identifying tidal signals from effects of other interior dynamics of Jupiter’s gravitational field.

  3. Ridges and tidal stress on Io

    USGS Publications Warehouse

    Bart, G.D.; Turtle, E.P.; Jaeger, W.L.; Keszthelyi, L.P.; Greenberg, R.

    2004-01-01

    Sets of ridges of uncertain origin are seen in twenty-nine high-resolution Galileo images, which sample seven locales on Io. These ridges are on the order of a few kilometers in length with a spacing of about a kilometer. Within each locale, the ridges have a consistent orientation, but the orientations vary from place to place. We investigate whether these ridges could be a result of tidal flexing of Io by comparing their orientations with the peak tidal stress orientations at the same locations. We find that ridges grouped near the equator are aligned either north-south or east-west, as are the predicted principal stress orientations there. It is not clear why particular groups run north-south and others east-west. The one set of ridges observed far from the equator (52?? S) has an oblique azimuth, as do the tidal stresses at those latitudes. Therefore, all observed ridges have similar orientations to the tidal stress in their region. This correlation is consistent with the hypothesis that tidal flexing of Io plays an important role in ridge formation. ?? 2004 Elsevier Inc. All rights reserved.

  4. Tidal characteristics of the gulf of Tonkin

    NASA Astrophysics Data System (ADS)

    Minh, Nguyen Nguyet; Patrick, Marchesiello; Florent, Lyard; Sylvain, Ouillon; Gildas, Cambon; Damien, Allain; Van Uu, Dinh

    2014-12-01

    The Gulf of Tonkin, situated in the South China Sea, is a zone of strong ecological, touristic and economic interest. Improving our knowledge of its hydro-sedimentary processes is of great importance to the sustainable development of the area. The scientific objective of this study is to revisit the dominant physical processes that characterize tidal dynamics in the Gulf of Tonkin using a high-resolution model and combination of all available data. Particular attention is thus given to model-data cross-examination using tidal gauges and coastal satellite altimetry and to model calibration derived from a set of sensitivity experiments to model parameters. The tidal energy budget of the gulf (energy flux and dissipation) is then analyzed and its resonance properties are evaluated and compared with idealized models and observations. Then, the tidal residual flow in both Eulerian and Lagrangian frameworks is evaluated. Finally, the problem of tidal frontogenesis is addressed to explain the observed summer frontal structures in chlorophyll concentrations.

  5. The mathematical analysis of breath alcohol profiles generated during breath exhalation.

    PubMed

    Gullberg, R G

    1990-01-01

    The mathematical analysis of time domain data provides a useful tool for evaluating biological and instrumental systems. Breath alcohol profile measurements generated during exhalation constitute biological signals that can be subjected to a variety of mathematical treatments. The present paper discusses the application of a variety of mathematical procedures to breath alcohol profiles. These mathematical procedures include model approximation, data smoothing, integration, differentiation, and fourier transformation. The different mathematical procedures provide insight into the physiology of breath alcohol measurement and suggest forensic as well as instrumental applications.

  6. The dependence of estuarine turbidity on tidal intrusion length, tidal range and residence time

    NASA Astrophysics Data System (ADS)

    Uncles, R. J.; Stephens, J. A.; Smith, R. E.

    2002-07-01

    It is shown that there is a marked tendency for long, strongly tidal estuaries to have greater suspended particulate matter (SPM) concentrations within their high-turbidity regions than shorter estuaries with comparable tidal ranges at their mouths, or weakly tidal estuaries. Using consistently derived data from 44 estuaries in Europe and the Americas, contours of the logarithm of maximum estuarine SPM concentration are shown to be reasonably smooth when plotted against the logarithm of mean spring tidal range (at the estuary mouth) and the logarithm of estuarine tidal length. Predictions from the plot are compared with published observations made in the Delaware, Scheldt, Rio de la Plata, Gironde, Bay of Fundy, Changjiang (Yangtze), Amazon, Patos Lagoon and the Hawkesbury Estuary and it is shown that, qualitatively, there are no serious discrepancies. Short, weakly tidal estuaries are predicted to have very low 'intrinsic' SPM concentrations. High SPM concentrations in these estuaries would most likely be the result of either locally generated wave resuspension, high freshwater sediment loads due to freshets, or intruding seawater carrying suspended sediments derived from wave activity in the coastal zone. Application of a generic tidal model demonstrates that longer estuaries possess faster tidal currents for a given tidal range at their mouth and, in the presence of a supply of erodable fine sediment, therefore (by implication) produce greater concentrations of SPM that can be accumulated within a turbidity maximum. The same is true if the tidal range is increased for estuaries of a given length. These features are illustrated by comparing surveys of SPM data from two large estuaries possessing greatly different tidal ranges (the microtidal, medium turbidity Potomac and the macrotidal, highly turbid Humber-Ouse) and a third, much smaller but strongly tidal estuary (the low-turbidity Tweed). It is demonstrated that longer estuaries tend to have longer flushing

  7. The dependence of estuarine turbidity on tidal intrusion length, tidal range and residence time

    USGS Publications Warehouse

    Uncles, R.J.; Stephens, J.A.; Smith, R.E.

    2002-01-01

    It is shown that there is a marked tendency for long, strongly tidal estuaries to have greater suspended particulate matter (SPM) concentrations within their high-turbidity regions than shorter estuaries with comparable tidal ranges at their mouths, or weakly tidal estuaries. Using consistently derived data from 44 estuaries in Europe and the Americas, contours of the logarithm of maximum estuarine SPM concentration are shown to be reasonably smooth when plotted against the logarithm of mean spring tidal range (at the estuary mouth) and the logarithm of estuarine tidal length. Predictions from the plot are compared with published observations made in the Delaware, Scheldt, Rio de la Plata, Gironde, Bay of Fundy, Changjiang (Yangtze), Amazon, Paros Lagoon and the Hawkesbury Estuary and it is shown that, qualitatively, there are no serious discrepancies. Short, weakly tidal estuaries are predicted to have very low 'intrinsic' SPM concentrations. High SPM concentrations in these estuaries would most likely be the result of either locally generated wave resuspension, high freshwater sediment loads due to freshets, or intruding seawater carrying suspended sediments derived from wave activity in the coastal zone. Application of a generic tidal model demonstrates that longer estuaries possess faster tidal currents for a given tidal range at their mouth and, in the presence of a supply of erodable fine sediment, therefore (by implication) produce greater concentrations of SPM that can be accumulated within a turbidity maximum. The same is true if the tidal range is increased for estuaries of a given length. These features are illustrated by comparing surveys of SPM data from two large estuaries possessing greatly different tidal ranges (the microtidal, medium turbidity Potomac and the macrotidal, highly turbid Humber-Ouse) and a third, much smaller but strongly tidal estuary (the low-turbidity Tweed). It is demonstrated that longer estuaries tend to have longer flushing

  8. Carotid body denervation improves autonomic and cardiac function and attenuates disordered breathing in congestive heart failure

    PubMed Central

    Marcus, Noah J; Rio, Rodrigo; Schultz, Evan P; Xia, Xiao-Hong; Schultz, Harold D

    2014-01-01

    In congestive heart failure (CHF), carotid body (CB) chemoreceptor activity is enhanced and is associated with oscillatory (Cheyne–Stokes) breathing patterns, increased sympathetic nerve activity (SNA) and increased arrhythmia incidence. We hypothesized that denervation of the CB (CBD) chemoreceptors would reduce SNA, reduce apnoea and arrhythmia incidence and improve ventricular function in pacing-induced CHF rabbits. Resting breathing, renal SNA (RSNA) and arrhythmia incidence were measured in three groups of animals: (1) sham CHF/sham–CBD (sham–sham); (2) CHF/sham–CBD (CHF–sham); and (3) CHF/CBD (CHF–CBD). Chemoreflex sensitivity was measured as the RSNA and minute ventilatory () responses to hypoxia and hypercapnia. Respiratory pattern was measured by plethysmography and quantified by an apnoea–hypopnoea index, respiratory rate variability index and the coefficient of variation of tidal volume. Sympatho-respiratory coupling (SRC) was assessed using power spectral analysis and the magnitude of the peak coherence function between tidal volume and RSNA frequency spectra. Arrhythmia incidence and low frequency/high frequency ratio of heart rate variability were assessed using ECG and blood pressure waveforms, respectively. RSNA and responses to hypoxia were augmented in CHF–sham and abolished in CHF–CBD animals. Resting RSNA was greater in CHF–sham compared to sham–sham animals (43 ± 5% max vs. 23 ± 2% max, P < 0.05), and this increase was not found in CHF–CBD animals (25 ± 1% max, P < 0.05 vs. CHF–sham). Low frequency/high frequency heart rate variability ratio was similarly increased in CHF and reduced by CBD (P < 0.05). Respiratory rate variability index, coefficient of variation of tidal volume and apnoea–hypopnoea index were increased in CHF–sham animals and reduced in CHF–CBD animals (P < 0.05). SRC (peak coherence) was increased in CHF–sham animals (sham–sham 0.49 ± 0.05; CHF–sham 0.79

  9. Coughing Wheezing Shortness of Breath Tightness in Chest

    MedlinePlus

    ... Current Issue Past Issues Coughing Wheezing Shortness of Breath Tightness in Chest Past Issues / Fall 2006 Table ... you cough a lot, wheeze, are short of breath or feel tightness in your chest, you might ...

  10. Meeting Reports for 2013: Recent Advances in Breath Biomarker Research

    EPA Science Inventory

    This article reports the efforts of the breath research community affiliated with the International Association of Breath Research (IABR) in disseminating research results in high profile technical meetings in the United States (US). Specifically, we describe presentations at a ...

  11. ALVEOLAR BREATH SAMPLING AND ANALYSIS IN HUMAN EXPOSURE ASSESSMENT STUDIES

    EPA Science Inventory

    Alveolar breath sampling and analysis can be extremely useful in exposure assessment studies involving volatile organic compounds (VOCs). Over recent years scientists from the EPA's National Exposure Research Laboratory have developed and refined an alveolar breath collection ...

  12. Pitfalls in the evaluation of shortness of breath.

    PubMed

    Wills, Charlotte Page; Young, Megann; White, Douglas W

    2010-02-01

    This article illustrates the challenges practitioners face evaluating shortness of breath, a common emergency department complaint. Through a series of patient encounters, pitfalls in the evaluation of shortness of breath are reviewed and discussed. PMID:19945605

  13. Tidal response of Europa's subsurface ocean

    NASA Astrophysics Data System (ADS)

    Karatekin, Özgür; Comblen, Richard; Toubeau, Jonathan; Deleersnijder, Eric; van Hoolst, Tim; Dehant, Veronique

    2010-05-01

    Observations of Cassini and Galileo spacecrafts suggest the presence of subsurface global water oceans under the icy shells of several satellites of Jupiter and Saturn. Previous studies have shown that in the presence of subsurface oceans, time-variable tides cause large periodic surface displacements and that tidal dissipation in the icy shell becomes a major energy source that can affect long-term orbital evolution. However, in most studies so far, the dynamics of these satellite oceans have been neglected. In the present study, we investigate the tidal response of the subsurface ocean of Europa to a time-varying potential. Two-dimensional nonlinear shallow water equations are solved on a sphere by means of a finite element code. The resulting ocean tidal flow velocities and surface displacements will be presented.

  14. Gravitational circulation in a tidal strait

    USGS Publications Warehouse

    Smith, P.E.; Cheng, R.T.; Burau, J.R.; Simpson, M.R.; ,

    1991-01-01

    Eight months of continuous measurements of tidal current profiles with an acoustic Doppler current profiler (ADCP) were made in Carquinez Strait, California, during 1988 for the purpose of estimating long-term variations in vertical profiles of Eulerian residual currents. Salinity stratification near the ADCP deployment site also was analyzed. The strength of density-driven gravitational circulation and the amount of salinity stratification in the strait varied significantly over the spring-neap tidal cycle. Density currents and stratification were greater during neap tides when vertical mixing from the tide is at a minimum. Landward residual currents along the bottom were observed only during neap tides. Simulations made with a three-dimensional model to supplement the field measurements show a significant, tidally induced lateral variation in residual currents across the strait. The Stokes drift of 1-2 cm/s in the strait is small relative to the speed of gravitational currents.

  15. Is slow slip in Cascadia tidally modulated?

    NASA Astrophysics Data System (ADS)

    Hawthorne, J. C.; Rubin, A. M.

    2009-12-01

    Several studies have shown that the seismic tremor in episodic tremor and slip is tidally modulated, suggesting a strong sensitivity to the rather small tidal stresses. We address whether the slip is also tidally modulated by examining data from six borehole strainmeters in northwest Washington and southern Vancouver Island. We use the processed data provided by Plate Boundary Observatory (PBO), which is resampled to 5-minute intervals. However, we recompute empirical corrections for tides, a long-term linear trend, and barometric pressure in the 50 days surrounding each slow slip event. We then fit sinusoids at the tidal periods to the processed data as proxies for the tidally modulated component of slip, along with a linear trend as a proxy for the net strain in the slow slip. The data are too noisy to allow detection any tidal modulation using only a single event and station. We therefore simultaneously fit data from multiple stations and from three slow slip events since 2007. This assumes that the phase of the tides at the slipping regions detected by all stations is the same and that the phase of the fault response to the tidal stress is constant. Combining the stations and events both reduces the noise at the tidal periods and creates a longer time series, which allows us to separate energy at the different tidal frequencies. We find significant tidal signals at the 12.4 and 25.8-hour periods which differ from zero at the 1.5 to 2-sigma level. Errors are estimated by bootstrapping the slow slip strain and by considering the tidal signal at times before the slow slip event. The 12.4 and 25.8-hour sinusoids have amplitudes of 23 (10-40 at 2-sigma) and 15 (0-30 at 2-sigma) percent of the maximum amplitude that does not allow the slow slip strain signal to change sign, where the mean strain rate is estimated from the linear trends fit to the slow slip data. In terms of slip rate, the sinusoids at each period could then modulate the slip rate 23 and 15 percent

  16. TIDAL TURBULENCE SPECTRA FROM A COMPLIANT MOORING

    SciTech Connect

    Thomson, Jim; Kilcher, Levi; Richmond, Marshall C.; Talbert, Joe; deKlerk, Alex; Polagye, Brian; Guerra, Maricarmen; Cienfuegos, Rodrigo

    2013-06-13

    A compliant mooring to collect high frequency turbulence data at a tidal energy site is evaluated in a series of short demon- stration deployments. The Tidal Turbulence Mooring (TTM) improves upon recent bottom-mounted approaches by suspend- ing Acoustic Doppler Velocimeters (ADVs) at mid-water depths (which are more relevant to tidal turbines). The ADV turbulence data are superior to Acoustic Doppler Current Profiler (ADCP) data, but are subject to motion contamination when suspended on a mooring in strong currents. In this demonstration, passive stabilization is shown to be sufficient for acquiring bulk statistics of the turbulence, without motion correction. With motion cor- rection (post-processing), data quality is further improved; the relative merits of direct and spectral motion correction are dis- cussed.

  17. DOUBLE TIDAL DISRUPTIONS IN GALACTIC NUCLEI

    SciTech Connect

    Mandel, Ilya; Levin, Yuri E-mail: yuri.levin@monash.edu

    2015-05-20

    A star on a nearly radial trajectory approaching a massive black hole (MBH) gets tidally disrupted if it comes sufficiently close to the MBH. Here we explore what happens to binary stars whose centers of mass approach the MBH on nearly radial orbits. The interaction with the MBH often leads to both stars being disrupted in sequence. We argue that such events could produce light curves that are substantially different from those of the single disruptions, with possible features such as two local maxima. Tidal forces from the MBH can also lead the binary components to collide; these merger products can form highly magnetized stars, whose subsequent tidal disruption may enable prompt jet formation.

  18. Oceanic tidal signals in magnetic satellite data

    NASA Astrophysics Data System (ADS)

    Wardinski, I.; Lesur, V.

    2015-12-01

    In this study we discuss the observation of oceanic tidal signals in magnetic satellite data. We analyse 10 years of CHAMP satellite data. The detection algorithm is applied on residual signal that remains after the derivation of GRIMM 42 (Lesur et al., 2015). The signals found represent the major tidal constituents, such as the M2 tide. However, other tidal constituents appear to be swallowed by unmodelled external and induced magnetic signal, particularly in equatorial and circumpolar regions. A part of the study also focuses on the temporal variability of the signal detection and its dependence on geomagnetic activity. Possible refinements to the detection algorithm and its applicability to SWARM data are also presented and discussed.

  19. Tidal analysis of Met rocket wind data

    NASA Technical Reports Server (NTRS)

    Bedinger, J. F.; Constantinides, E.

    1976-01-01

    A method of analyzing Met Rocket wind data is described. Modern tidal theory and specialized analytical techniques were used to resolve specific tidal modes and prevailing components in observed wind data. A representation of the wind which is continuous in both space and time was formulated. Such a representation allows direct comparison with theory, allows the derivation of other quantities such as temperature and pressure which in turn may be compared with observed values, and allows the formation of a wind model which extends over a broader range of space and time. Significant diurnal tidal modes with wavelengths of 10 and 7 km were present in the data and were resolved by the analytical technique.

  20. Tidal deceleration of the moon's mean motion

    NASA Technical Reports Server (NTRS)

    Cheng, M. K.; Eanes, R. J.; Tapley, B. D.

    1992-01-01

    The secular change in the mean motion of the moon, n, caused by the tidal dissipation in the ocean and solid earth is due primarily to the effect of the diurnal and semidiurnal tides. The long-period ocean tides produce an increase in n, but the effects are only 1 percent of the diurnal and semidiurnal ocean tides. In this investigation, expressions for these effects are obtained by developing the tidal potential in the ecliptic reference system. The computation of the amplitude of equilibrium tide and the phase corrections is also discussed. The averaged tidal deceleration of the moon's mean motion, n, from the most recent satellite ocean tide solutions is -25.25 +/- 0.4 arcseconds/sq century. The value for n inferred from the satellite-determined ocean-tide solution is in good agreement with the value obtained from the analysis of 20 years of lunar laser-ranging observations.

  1. Tidal truncation and barotropic convergence in a channel network tidally driven from opposing entrances

    USGS Publications Warehouse

    Warner, J.C.; Schoellhamer, D.; Schladow, G.

    2003-01-01

    Residual circulation patterns in a channel network that is tidally driven from entrances on opposite sides are controlled by the temporal phasing and spatial asymmetry of the two forcing tides. The Napa/Sonoma Marsh Complex in San Francisco Bay, CA, is such a system. A sill on the west entrance to the system prevents a complete tidal range at spring tides that results in tidal truncation of water levels. Tidal truncation does not occur on the east side but asymmetries develop due to friction and off-channel wetland storage. The east and west asymmetric tides meet in the middle to produce a barotropic convergence zone that controls the transport of water and sediment. During spring tides, tidally averaged water-surface elevations are higher on the truncated west side. This creates tidally averaged fluxes of water and sediment to the east. During neap tides, the water levels are not truncated and the propagation speed of the tides controls residual circulation, creating a tidally averaged flux in the opposite direction. ?? 2003 Elsevier Science B.V. All rights reserved.

  2. Tidal constituents from remote sensing image sequences

    NASA Astrophysics Data System (ADS)

    Mied, Richard P.; Snow, Charlotte M.; Smith, Geoffrey B.; Bachmann, Charles M.; Korwan, Daniel R.; Fusina, Robert A.; Vermillion, Michael S.; Hagen, Rick A.

    2013-01-01

    We address the problem of obtaining tidal constituents from a series of shoreline positions derived from time-sequential airborne imagery of the intertidal zone. A multi-sensor experiment (Bachmann et al., 2012) conducted at the Virginia Coast Reserve Long-Term Ecological Research (VCR LTER) site supplied in-situ and airborne data. Hyperspectral and infrared shoreline imagery of the VCR LTER barrier islands, shallow lagoons, and mainland coastal areas as well as topographic LiDAR data were obtained from the same air platform over a nine-day period, and LiDAR and in-situ topographic beach surveys were used to specify the beach bathymetry and derive a Digital Elevation Model (DEM) over the primary area focused on in this paper at Wreck Island, VA. The DEM and shoreline positions are used to obtain a time sequence of tidal heights; these are found to be consistent with a time series from a GPS-equipped tide gage float anchored nearby. A least-squares fit of the five largest tidal constituents (M2, N2, S2, O1, K1) to this one-week record indicates that the first three can be retrieved with only a ±15-20 % error, as determined by the one-year sea-surface height time series from a nearby NOAA Sea Surface Height (SSH) station at Wachapreague, VA. The broader question of how many images are needed to obtain tidal constituents from an annual record is also addressed. Using SSH values from a NOAA tide gage station as a surrogate for image-derived SSH values, we progressively decimate a yearlong tide record, calculating its tidal constituents at each level of decimation. We find that that only one image every ten days is needed to retrieve the five largest tidal constituents to within a 10% error. www.vcrlter.virginia.edu

  3. On inter-tidal transport equation

    USGS Publications Warehouse

    Cheng, Ralph T.; Feng, Shizuo; Pangen, Xi

    1989-01-01

    The transports of solutes, sediments, nutrients, and other tracers are fundamental to the interactive physical, chemical, and biological processes in estuaries. The characteristic time scales for most estuarine biological and chemical processes are on the order of several tidal cycles or longer. To address the long-term transport mechanism meaningfully, the formulation of an inter-tidal conservation equation is the main subject of this paper. The commonly used inter-tidal conservation equation takes the form of a convection-dispersion equation in which the convection is represented by the Eulerian residual current, and the dispersion terms are due to the introduction of a Fickian hypothesis, unfortunately, the physical significance of this equation is not clear, and the introduction of a Fickian hypothesis is at best an ad hoc approximation. Some recent research results on the Lagrangian residual current suggest that the long-term transport problem is more closely related to the Lagrangian residual current than to the Eulerian residual current. With the aid of additional insight of residual current, the inter-tidal transport equation has been reformulated in this paper using a small perturbation method for a weakly nonlinear tidal system. When tidal flows can be represented by an M2 system, the new intertidal transport equation also takes the form of a convective-dispersion equation without the introduction of a Fickian hypothesis. The convective velocity turns out to be the first order Lagrangian residual current (the sum of the Eulerian residual current and the Stokes’ drift), and the correlation terms take the form of convection with the Stokes’ drift as the convective velocity. The remaining dispersion terms are perturbations of lower order solution to higher order solutions due to shear effect and turbulent mixing.

  4. 21 CFR 868.5620 - Breathing mouthpiece.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... connects with diagnostic or therapeutic respiratory devices. (b) Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5620 Breathing mouthpiece....

  5. The Air We Breathe. Activity Packet.

    ERIC Educational Resources Information Center

    Connecticut State Dept. of Environmental Protection, Hartford.

    This packet of materials is intended to provide teachers with an interdisciplinary approach to integrating air quality education into the existing curriculum of Connecticut schools. The unit is designed to complement the student booklet "The Air We Breathe," which is included. A major portion of the document is comprised of teaching activities.…

  6. Monitoring diurnal changes in exhaled human breath.

    PubMed

    Sinues, Pablo Martinez-Lozano; Kohler, Malcolm; Zenobi, Renato

    2013-01-01

    The development of noninvasive analytical techniques is of interest to the field of chronobiology, in order to reveal the human metabolome that seems to show temporal patterns and to predict internal body time. We report on the real-time mass spectrometric analysis of human breath as a potential method to be used in this field. The breath of 12 subjects was analyzed during 9 days by secondary electrospray ionization-mass spectrometry (SESI-MS). The samples were collected during four time slots: morning (8:00-11:00), before lunch (11:00-13:00), after lunch (13:00-15:00), and late afternoon (15:00-18:00). A total of 203 mass spectra were statistically analyzed. Univariate analysis revealed a number of features with a marked temporal behavior. Principal component analysis/canonical analysis showed a clear temporal evolution of the breath patterns. A blind cross-validation yielded 84% of correct classifications of the time slot at which the breath samples were collected. We conclude that this approach seems to have potential for the investigation of biological clocks, including the description of internal body time, which may have important implications for the timing of pharmacotherapy. PMID:23198821

  7. Air breathing direct methanol fuel cell

    DOEpatents

    Ren, Xiaoming

    2002-01-01

    An air breathing direct methanol fuel cell is provided with a membrane electrode assembly, a conductive anode assembly that is permeable to air and directly open to atmospheric air, and a conductive cathode assembly that is permeable to methanol and directly contacting a liquid methanol source.

  8. Fast and Accurate Exhaled Breath Ammonia Measurement

    PubMed Central

    Solga, Steven F.; Mudalel, Matthew L.; Spacek, Lisa A.; Risby, Terence H.

    2014-01-01

    This exhaled breath ammonia method uses a fast and highly sensitive spectroscopic method known as quartz enhanced photoacoustic spectroscopy (QEPAS) that uses a quantum cascade based laser. The monitor is coupled to a sampler that measures mouth pressure and carbon dioxide. The system is temperature controlled and specifically designed to address the reactivity of this compound. The sampler provides immediate feedback to the subject and the technician on the quality of the breath effort. Together with the quick response time of the monitor, this system is capable of accurately measuring exhaled breath ammonia representative of deep lung systemic levels. Because the system is easy to use and produces real time results, it has enabled experiments to identify factors that influence measurements. For example, mouth rinse and oral pH reproducibly and significantly affect results and therefore must be controlled. Temperature and mode of breathing are other examples. As our understanding of these factors evolves, error is reduced, and clinical studies become more meaningful. This system is very reliable and individual measurements are inexpensive. The sampler is relatively inexpensive and quite portable, but the monitor is neither. This limits options for some clinical studies and provides rational for future innovations. PMID:24962141

  9. Coordination of breathing with nonrespiratory activities.

    PubMed

    Bartlett, Donald; Leiter, James C

    2012-04-01

    Many articles in this section of Comprehensive Physiology are concerned with the development and function of a central pattern generator (CPG) for the control of breathing in vertebrate animals. The action of the respiratory CPG is extensively modified by cortical and other descending influences as well as by feedback from peripheral sensory systems. The central nervous system also incorporates other CPGs, which orchestrate a wide variety of discrete and repetitive, voluntary and involuntary movements. The coordination of breathing with these other activities requires interaction and coordination between the respiratory CPG and those governing the nonrespiratory activities. Most of these interactions are complex and poorly understood. They seem to involve both conventional synaptic crosstalk between groups of neurons and fluid identity of neurons as belonging to one CPG or another: neurons that normally participate in breathing may be temporarily borrowed or hijacked by a competing or interrupting activity. This review explores the control of breathing as it is influenced by many activities that are generally considered to be nonrespiratory. The mechanistic detail varies greatly among topics, reflecting the wide variety of pertinent experiments.

  10. Crew equipment applications - Firefighter's Breathing System.

    NASA Technical Reports Server (NTRS)

    Smith, W. L.

    1973-01-01

    The Firefighter's Breathing System (FBS) represents a significant step in applying NASA's crew equipment technologists and technologies to civilian sector problems. This paper describes the problem, the utilization of user-design committees as a forum for development of design goals, the design of the FBS, and the field test program to be conducted.

  11. Investigation on Tidal Components in GPS Coordinates

    NASA Astrophysics Data System (ADS)

    Araszkiewicz, Andrzej; Bogusz, Janusz; Figurski, Mariusz

    2009-01-01

    This paper presents analyses on the GPS coordinates from sub-diurnal solutions of EPN data provided by Warsaw Military University of Technology. The aim of this research is to investigate the way the tidal models used in Bernese software (solid Earth and ocean tides as well) fit to the individual conditions of EPN stations. The 1-hour solution technique of GPS data processing was utilized to obtain coordinates of above 70 EPN stations. Additionally several Polish permanent sites with clearly seen oscillations were examined. This processing technique allowed us to recognize diurnal and sub-diurnal residual oscillations which could be next utilized for validation of the tidal models.

  12. SN 2012hn: a tidal detonation event?

    NASA Astrophysics Data System (ADS)

    Maccarone, Thomas

    2013-09-01

    We propose for a 30 kilosecond observation of SN 2102hn, a Ca-rich gap transient. These enigmatic objects, with properties intermediate between those of classical novae and Type Ia supernovae, can be well-explained by tidal detonations of low mass white dwarfs by intermediate mass black holes. In such a case, fall-back accretion of the tidal debris would power an X-ray source for which we propose to search. Because supermassive black holes will swallow white dwarfs whole, a successful outcome to this proposal would both explain the Ca-rich gap transients *and* establish the existence of intermediate mass black holes.

  13. Tidally Heated ExoMoons (THEM)

    NASA Astrophysics Data System (ADS)

    Dobos, V.

    2014-04-01

    More than a thousand exoplanets have been identified to date (Schneider 2014); however, moons orbiting exoplanets have not been discovered, yet. Nevertheless, it is probable that exomoons will be detected in the near future if they are not much more rare in exoplanetary systems than they are in the Solar System (Heller & Barnes 2013, Peters & Turner 2013, Kaltenegger 2010). For this reason it is important to begin to develop basic theoretical models of exomoons in advance of the first detections. Habitability is a particularly important aspect, since life might well develop on a non-planetary body if it has suitable characteristics and environmentals. Tidal forces produced by the planet which the moon orbits can induce friction inside the satellite that will have a warming effect (Peale et al. 1979). In the Solar System there are several examples for moons that have significant heating due to tidal forces. On exomoons that are too far from their central star to have habitable surface temperatures due to radiative heating, it is possible that warmth area of the surface produced by tidal heating could allow the emergence of life (Scharf 2006). This investigation focuses on tidal heating, studying the surface temperature of hypothetical exomoons for different orbital and interior parameters of the body. The aim of our research is to describe the conditions that allow the existence of water reservoirs in the liquid phase state on or near the surface. We modified and extended the public code of Heller & Barnes (2013) for the purposes of this investigation. References Heller, R., Barnes, R. 2013 Exomoon Habitability Constrained by Illumination and Tidal Heating, Astrobiology 13, 18 Kaltenegger, L. 2010 Characterizing habitable exomoons, The Astrophysical Journal Letters 712, 125 Peale, S. J., Cassen, P., Reynolds, R. T. 1979 Melting of Io by Tidal Dissipation, Science 203, 892 Peters, M. A., Turner, E. L. 2013 On the direct imaging of tidally heated exomoons, The

  14. Tidal friction in the solid earth

    NASA Technical Reports Server (NTRS)

    Zschau, J.

    1978-01-01

    The earth's imperfectly elastic response to body and loading tidal forces is discussed using complex Love numbers and complex mass loading coefficients. Exact analytical expressions were derived relating the energy dissipation within an inhomogeneous, compressible solid earth to the surface values of these complex characteristic numbers, thus relating the global dissipation function Q to the phase shifts in the potential, gravity, tilt, strain and displacement tides. Integration of a global ocean tidal model shows that energy dissipated in the solid earth due to ocean loading is at least 10% of that dissipated in the body tides.

  15. Tidal disruption of stars by SMBHs

    NASA Astrophysics Data System (ADS)

    Komossa, S.

    2016-06-01

    The tidal disruption and subsequent accretion of stars by supermassive black holes produces spectacular flares in the X-ray sky. First found with ROSAT, ongoing and upcoming sky surveys will find these events in the 1000s. In X-rays, tidal disruption events (TDEs) provide us with powerful new probes of accretion physics under extreme conditions, of the formation of disk winds, of relativistic effects near the SMBH, and of the presence of supermassive binary black holes. This talk reviews the status of observations, and discusses future prospects. XMM-Newton will continue to play an important role in identifying new events and carry out spectroscopic follow-ups.

  16. 42 CFR 84.81 - Compressed breathing gas and liquefied breathing gas containers; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from American National Standards... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.81 Compressed...

  17. 42 CFR 84.81 - Compressed breathing gas and liquefied breathing gas containers; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from American National Standards... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.81 Compressed...

  18. Contribution to the theory of tidal oscillations of an elastic earth. External tidal potential

    NASA Technical Reports Server (NTRS)

    Musen, P.

    1974-01-01

    The differential equations of the tidal oscillations of the earth were established under the assumption that the interior of the earth is laterally inhomogeneous. The theory was developed using vectorial and dyadic symbolism to shorten the exposition and to reduce the differential equations to a symmetric form convenient for programming and for numerical integration. The formation of tidal buldges on the surfaces of discontinuity and the changes in the internal density produce small periodic variations in the exterior geopotential which are reflected in the motion of artificial satellites. The analoques of Love elastic parameters in the expansion of exterior tidal potential reflect the asymmetric and inhomogeneous structure of the interior of the earth.

  19. 46 CFR 197.340 - Breathing gas supply.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... diver. (d) A primary breathing gas supply for SCUBA diving must be sufficient to support the diver for...) A diver-carried reserve breathing gas supply for SCUBA diving must be sufficient to allow the diver... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.340 Breathing gas supply. (a) A...

  20. 46 CFR 197.340 - Breathing gas supply.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... diver. (d) A primary breathing gas supply for SCUBA diving must be sufficient to support the diver for...) A diver-carried reserve breathing gas supply for SCUBA diving must be sufficient to allow the diver... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.340 Breathing gas supply. (a) A...

  1. 42 CFR 84.91 - Breathing resistance test; exhalation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Breathing resistance test; exhalation. 84.91...-Contained Breathing Apparatus § 84.91 Breathing resistance test; exhalation. (a) Resistance to exhalation airflow will be measured in the facepiece or mouthpiece of open-circuit apparatus with air flowing at...

  2. 42 CFR 84.91 - Breathing resistance test; exhalation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Breathing resistance test; exhalation. 84.91...-Contained Breathing Apparatus § 84.91 Breathing resistance test; exhalation. (a) Resistance to exhalation airflow will be measured in the facepiece or mouthpiece of open-circuit apparatus with air flowing at...

  3. 42 CFR 84.91 - Breathing resistance test; exhalation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Breathing resistance test; exhalation. 84.91...-Contained Breathing Apparatus § 84.91 Breathing resistance test; exhalation. (a) Resistance to exhalation airflow will be measured in the facepiece or mouthpiece of open-circuit apparatus with air flowing at...

  4. 42 CFR 84.91 - Breathing resistance test; exhalation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Breathing resistance test; exhalation. 84.91...-Contained Breathing Apparatus § 84.91 Breathing resistance test; exhalation. (a) Resistance to exhalation airflow will be measured in the facepiece or mouthpiece of open-circuit apparatus with air flowing at...

  5. 46 CFR 108.703 - Self-contained breathing apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... DESIGN AND EQUIPMENT Miscellaneous Equipment § 108.703 Self-contained breathing apparatus. (a) Each unit must be equipped with a self-contained breathing apparatus described in § 108.497(a) to use as... 46 Shipping 4 2010-10-01 2010-10-01 false Self-contained breathing apparatus. 108.703 Section...

  6. 46 CFR 108.635 - Self-contained breathing apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... DESIGN AND EQUIPMENT Equipment Markings and Instructions § 108.635 Self-contained breathing apparatus. Each locker or space containing self-contained breathing apparatus must be marked: “SELF CONTAINED... 46 Shipping 4 2011-10-01 2011-10-01 false Self-contained breathing apparatus. 108.635 Section...

  7. 46 CFR 108.635 - Self-contained breathing apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... DESIGN AND EQUIPMENT Equipment Markings and Instructions § 108.635 Self-contained breathing apparatus. Each locker or space containing self-contained breathing apparatus must be marked: “SELF CONTAINED... 46 Shipping 4 2010-10-01 2010-10-01 false Self-contained breathing apparatus. 108.635 Section...

  8. 46 CFR 169.736 - Self-contained breathing apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Self-contained breathing apparatus. 169.736 Section 169... VESSELS Vessel Control, Miscellaneous Systems, and Equipment Markings § 169.736 Self-contained breathing apparatus. Each locker or space containing self-contained breathing apparatus must be marked...

  9. 46 CFR 108.703 - Self-contained breathing apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... DESIGN AND EQUIPMENT Miscellaneous Equipment § 108.703 Self-contained breathing apparatus. (a) Each unit must be equipped with a self-contained breathing apparatus described in § 108.497(a) to use as... 46 Shipping 4 2011-10-01 2011-10-01 false Self-contained breathing apparatus. 108.703 Section...

  10. 46 CFR 169.736 - Self-contained breathing apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Self-contained breathing apparatus. 169.736 Section 169... VESSELS Vessel Control, Miscellaneous Systems, and Equipment Markings § 169.736 Self-contained breathing apparatus. Each locker or space containing self-contained breathing apparatus must be marked...

  11. 46 CFR 197.340 - Breathing gas supply.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Breathing gas supply. 197.340 Section 197.340 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.340 Breathing gas supply. (a) A primary breathing gas supply for surface-supplied diving must be sufficient to support the following for...

  12. 46 CFR 197.340 - Breathing gas supply.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Breathing gas supply. 197.340 Section 197.340 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.340 Breathing gas supply. (a) A primary breathing gas supply for surface-supplied diving must be sufficient to support the following for...

  13. 21 CFR 868.5330 - Breathing gas mixer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Breathing gas mixer. 868.5330 Section 868.5330...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5330 Breathing gas mixer. (a) Identification. A breathing gas mixer is a device intended for use in conjunction with a respiratory...

  14. 46 CFR 197.340 - Breathing gas supply.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Breathing gas supply. 197.340 Section 197.340 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.340 Breathing gas supply. (a) A primary breathing gas supply for surface-supplied diving must be sufficient to support the following for...

  15. 21 CFR 868.5330 - Breathing gas mixer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Breathing gas mixer. 868.5330 Section 868.5330...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5330 Breathing gas mixer. (a) Identification. A breathing gas mixer is a device intended for use in conjunction with a respiratory...

  16. 21 CFR 868.5330 - Breathing gas mixer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Breathing gas mixer. 868.5330 Section 868.5330...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5330 Breathing gas mixer. (a) Identification. A breathing gas mixer is a device intended for use in conjunction with a respiratory...

  17. 21 CFR 868.5240 - Anesthesia breathing circuit.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Anesthesia breathing circuit. 868.5240 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5240 Anesthesia breathing circuit. (a) Identification. An anesthesia breathing circuit is a device that is intended to administer medical gases to...

  18. 21 CFR 868.5240 - Anesthesia breathing circuit.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Anesthesia breathing circuit. 868.5240 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5240 Anesthesia breathing circuit. (a) Identification. An anesthesia breathing circuit is a device that is intended to administer medical gases to...

  19. Human respiratory deposition of particles during oronasal breathing

    NASA Astrophysics Data System (ADS)

    Swift, David L.; Proctor, Donald F.

    Deposition of particles in the tracheobronchial and pulmonary airways is computed as a function of particle size, correcting for deposition in the parallel nasal and oral airways with oronasal breathing. Thoracic deposition is lower at all sizes for oronasal breathing than for mouth breathing via tube, and is negligible for aerodynamic equivalent diameters of 10 μm or larger.

  20. Oral Breathing Challenge in Participants with Vocal Attrition

    ERIC Educational Resources Information Center

    Sivasankar, Mahalakshmi; Fisher, Kimberly V.

    2003-01-01

    Vocal folds undergo osmotic challenge by mouth breathing during singing, exercising, and loud speaking. Just 15 min of obligatory oral breathing, to dry the vocal folds, increases phonation threshold pressure (P[subscript th]) and expiratory vocal effort in healthy speakers (M. Sivasankar & K. Fisher, 2002). We questioned whether oral breathing is…

  1. A convenient and reliable method for carbogen breathing in man.

    PubMed

    Kaanders, J H; van der Maazen, R W

    1993-12-01

    The feasibility of carbogen breathing and the intake of nicotinamide in combination with radiation therapy is currently being tested for clinical application. A dependable and convenient system for carbogen breathing is presented which can be easily combined with techniques for immobilization of the patient. The proposed method ensures adequate breathing of carbogen.

  2. 46 CFR 197.312 - Breathing supply hoses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Breathing supply hoses. 197.312 Section 197.312 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.312 Breathing supply hoses. (a) Each breathing supply hose must— (1) Have a maximum working pressure that is equal to or exceeds— (i) The...

  3. 46 CFR 197.456 - Breathing supply hoses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Breathing supply hoses. 197.456 Section 197.456 Shipping....456 Breathing supply hoses. (a) The diving supervisor shall insure that— (1) Each breathing supply hose is pressure tested prior to being placed into initial service and every 24 months thereafter to...

  4. 46 CFR 197.456 - Breathing supply hoses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Breathing supply hoses. 197.456 Section 197.456 Shipping....456 Breathing supply hoses. (a) The diving supervisor shall insure that— (1) Each breathing supply hose is pressure tested prior to being placed into initial service and every 24 months thereafter to...

  5. 46 CFR 197.312 - Breathing supply hoses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Breathing supply hoses. 197.312 Section 197.312 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.312 Breathing supply hoses. (a) Each breathing supply hose must— (1) Have a maximum working pressure that is equal to or exceeds— (i) The...

  6. 46 CFR 197.456 - Breathing supply hoses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Breathing supply hoses. 197.456 Section 197.456 Shipping....456 Breathing supply hoses. (a) The diving supervisor shall insure that— (1) Each breathing supply hose is pressure tested prior to being placed into initial service and every 24 months thereafter to...

  7. 46 CFR 197.312 - Breathing supply hoses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Breathing supply hoses. 197.312 Section 197.312 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.312 Breathing supply hoses. (a) Each breathing supply hose must— (1) Have a maximum working pressure that is equal to or exceeds— (i) The...

  8. 46 CFR 197.312 - Breathing supply hoses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Breathing supply hoses. 197.312 Section 197.312 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.312 Breathing supply hoses. (a) Each breathing supply hose must— (1) Have a maximum working pressure that is equal to or exceeds— (i) The...

  9. 46 CFR 197.456 - Breathing supply hoses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Breathing supply hoses. 197.456 Section 197.456 Shipping....456 Breathing supply hoses. (a) The diving supervisor shall insure that— (1) Each breathing supply hose is pressure tested prior to being placed into initial service and every 24 months thereafter to...

  10. 46 CFR 197.456 - Breathing supply hoses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Breathing supply hoses. 197.456 Section 197.456 Shipping....456 Breathing supply hoses. (a) The diving supervisor shall insure that— (1) Each breathing supply hose is pressure tested prior to being placed into initial service and every 24 months thereafter to...

  11. 46 CFR 197.312 - Breathing supply hoses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Breathing supply hoses. 197.312 Section 197.312 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.312 Breathing supply hoses. (a) Each breathing supply hose must— (1) Have a maximum working pressure that is equal to or exceeds— (i) The...

  12. 42 CFR 84.152 - Breathing tube test; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Breathing tube test; minimum requirements. 84.152... Respirators § 84.152 Breathing tube test; minimum requirements. (a)(1) Type A and Type B supplied-air respirators shall employ one or two flexible breathing tubes of the nonkinking type which extend from...

  13. 42 CFR 84.115 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Breathing tubes; minimum requirements. 84.115 Section 84.115 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... § 84.115 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction with...

  14. 42 CFR 84.132 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Breathing tubes; minimum requirements. 84.132 Section 84.132 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Respirators § 84.132 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction...

  15. 42 CFR 84.195 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Breathing tubes; minimum requirements. 84.195 Section 84.195 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Cartridge Respirators § 84.195 Breathing tubes; minimum requirements. Flexible breathing tubes used...

  16. 42 CFR 84.172 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Breathing tubes; minimum requirements. 84.172... Air-Purifying Particulate Respirators § 84.172 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction with respirators shall be designed and constructed to prevent:...

  17. 42 CFR 84.1132 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Breathing tubes; minimum requirements. 84.1132 Section 84.1132 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Gas Masks § 84.1132 Breathing tubes; minimum requirements. (a) Flexible breathing tubes used...

  18. 42 CFR 84.115 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Breathing tubes; minimum requirements. 84.115 Section 84.115 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... § 84.115 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction with...

  19. 42 CFR 84.195 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Breathing tubes; minimum requirements. 84.195 Section 84.195 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Cartridge Respirators § 84.195 Breathing tubes; minimum requirements. Flexible breathing tubes used...

  20. 42 CFR 84.152 - Breathing tube test; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Breathing tube test; minimum requirements. 84.152... Respirators § 84.152 Breathing tube test; minimum requirements. (a)(1) Type A and Type B supplied-air respirators shall employ one or two flexible breathing tubes of the nonkinking type which extend from...

  1. 42 CFR 84.1132 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Breathing tubes; minimum requirements. 84.1132 Section 84.1132 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Gas Masks § 84.1132 Breathing tubes; minimum requirements. (a) Flexible breathing tubes used...

  2. 42 CFR 84.172 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Breathing tubes; minimum requirements. 84.172... Air-Purifying Particulate Respirators § 84.172 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction with respirators shall be designed and constructed to prevent:...

  3. 42 CFR 84.195 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Breathing tubes; minimum requirements. 84.195 Section 84.195 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Cartridge Respirators § 84.195 Breathing tubes; minimum requirements. Flexible breathing tubes used...

  4. 42 CFR 84.152 - Breathing tube test; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Breathing tube test; minimum requirements. 84.152... Respirators § 84.152 Breathing tube test; minimum requirements. (a)(1) Type A and Type B supplied-air respirators shall employ one or two flexible breathing tubes of the nonkinking type which extend from...

  5. 42 CFR 84.1132 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Breathing tubes; minimum requirements. 84.1132 Section 84.1132 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Gas Masks § 84.1132 Breathing tubes; minimum requirements. (a) Flexible breathing tubes used...

  6. 42 CFR 84.195 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Breathing tubes; minimum requirements. 84.195 Section 84.195 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Cartridge Respirators § 84.195 Breathing tubes; minimum requirements. Flexible breathing tubes used...

  7. 42 CFR 84.1132 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Breathing tubes; minimum requirements. 84.1132 Section 84.1132 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Gas Masks § 84.1132 Breathing tubes; minimum requirements. (a) Flexible breathing tubes used...

  8. 42 CFR 84.132 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Breathing tubes; minimum requirements. 84.132 Section 84.132 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Respirators § 84.132 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction...

  9. 42 CFR 84.115 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Breathing tubes; minimum requirements. 84.115 Section 84.115 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... § 84.115 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction with...

  10. 42 CFR 84.172 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Breathing tubes; minimum requirements. 84.172... Air-Purifying Particulate Respirators § 84.172 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction with respirators shall be designed and constructed to prevent:...

  11. 42 CFR 84.132 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Breathing tubes; minimum requirements. 84.132 Section 84.132 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Respirators § 84.132 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction...

  12. 42 CFR 84.172 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Breathing tubes; minimum requirements. 84.172... Air-Purifying Particulate Respirators § 84.172 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction with respirators shall be designed and constructed to prevent:...

  13. 42 CFR 84.132 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Breathing tubes; minimum requirements. 84.132 Section 84.132 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Respirators § 84.132 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction...

  14. 42 CFR 84.132 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Breathing tubes; minimum requirements. 84.132 Section 84.132 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Respirators § 84.132 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction...

  15. 42 CFR 84.115 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Breathing tubes; minimum requirements. 84.115 Section 84.115 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... § 84.115 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction with...

  16. 42 CFR 84.152 - Breathing tube test; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Breathing tube test; minimum requirements. 84.152... Respirators § 84.152 Breathing tube test; minimum requirements. (a)(1) Type A and Type B supplied-air respirators shall employ one or two flexible breathing tubes of the nonkinking type which extend from...

  17. 42 CFR 84.152 - Breathing tube test; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Breathing tube test; minimum requirements. 84.152... Respirators § 84.152 Breathing tube test; minimum requirements. (a)(1) Type A and Type B supplied-air respirators shall employ one or two flexible breathing tubes of the nonkinking type which extend from...

  18. 42 CFR 84.115 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Breathing tubes; minimum requirements. 84.115 Section 84.115 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... § 84.115 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction with...

  19. 42 CFR 84.172 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Breathing tubes; minimum requirements. 84.172... Air-Purifying Particulate Respirators § 84.172 Breathing tubes; minimum requirements. Flexible breathing tubes used in conjunction with respirators shall be designed and constructed to prevent:...

  20. 42 CFR 84.1132 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Breathing tubes; minimum requirements. 84.1132 Section 84.1132 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Gas Masks § 84.1132 Breathing tubes; minimum requirements. (a) Flexible breathing tubes used...

  1. 42 CFR 84.195 - Breathing tubes; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Breathing tubes; minimum requirements. 84.195 Section 84.195 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL... Cartridge Respirators § 84.195 Breathing tubes; minimum requirements. Flexible breathing tubes used...

  2. 42 CFR 84.90 - Breathing resistance test; inhalation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Breathing resistance test; inhalation. 84.90...-Contained Breathing Apparatus § 84.90 Breathing resistance test; inhalation. (a) Resistance to inhalation... machine as described in § 84.88. (b) The inhalation resistance of open-circuit apparatus shall not...

  3. 42 CFR 84.90 - Breathing resistance test; inhalation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Breathing resistance test; inhalation. 84.90...-Contained Breathing Apparatus § 84.90 Breathing resistance test; inhalation. (a) Resistance to inhalation... machine as described in § 84.88. (b) The inhalation resistance of open-circuit apparatus shall not...

  4. 42 CFR 84.90 - Breathing resistance test; inhalation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Breathing resistance test; inhalation. 84.90...-Contained Breathing Apparatus § 84.90 Breathing resistance test; inhalation. (a) Resistance to inhalation... machine as described in § 84.88. (b) The inhalation resistance of open-circuit apparatus shall not...

  5. 42 CFR 84.90 - Breathing resistance test; inhalation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Breathing resistance test; inhalation. 84.90...-Contained Breathing Apparatus § 84.90 Breathing resistance test; inhalation. (a) Resistance to inhalation... machine as described in § 84.88. (b) The inhalation resistance of open-circuit apparatus shall not...

  6. 42 CFR 84.90 - Breathing resistance test; inhalation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Breathing resistance test; inhalation. 84.90...-Contained Breathing Apparatus § 84.90 Breathing resistance test; inhalation. (a) Resistance to inhalation... machine as described in § 84.88. (b) The inhalation resistance of open-circuit apparatus shall not...

  7. Tidal capture of stars by a massive black hole

    NASA Technical Reports Server (NTRS)

    Novikov, I. D.; Pethick, C. J.; Polnarev, A. G.

    1992-01-01

    The processes leading to tidal capture of stars by a massive black hole and the consequences of these processes in a dense stellar cluster are discussed in detail. When the amplitude of a tide and the subsequent oscillations are sufficiently large, the energy deposited in a star after periastron passage and formation of a bound orbit cannot be estimated directly using the linear theory of oscillations of a spherical star, but rather numerical estimates must be used. The evolution of a star after tidal capture is discussed. The maximum ratio R of the cross-section for tidal capture to that for tidal disruption is about 3 for real systems. For the case of a stellar system with an empty capture loss cone, even in the case when the impact parameter for tidal capture only slightly exceeds the impact parameter for direct tidal disruption, tidal capture would be much more important than tidal disruption.

  8. Breath measurements as volatile organic compound biomarkers.

    PubMed Central

    Wallace, L; Buckley, T; Pellizzari, E; Gordon, S

    1996-01-01

    A brief review of the uses of breath analysis in studies of environmental exposure to volatile organic compounds (VOCs) is provided. The U.S. Environmental Protection Agency's large-scale Total Exposure Assessment Methodology Studies have measured concentrations of 32 target VOCs in the exhaled breath of about 800 residents of various U.S. cities. Since the previous 12-hr integrated personal air exposures to the same chemicals were also measured, the relation between exposure and body burden is illuminated. Another major use of the breath measurements has been to detect unmeasured pathways of exposure; the major impact of active smoking on exposure to benzene and styrene was detected in this way. Following the earlier field studies, a series of chamber studies have provided estimates of several important physiological parameters. Among these are the fraction, f, of the inhaled chemical that is exhaled under steady-state conditions and the residence times. tau i in several body compartments, which may be associated with the blood (or liver), organs, muscle, and fat. Most of the targeted VOCs appear to have similar residence times of a few minutes, 30 min, several hours, and several days in the respective tissue groups. Knowledge of these parameters can be helpful in estimating body burden from exposure or vice versa and in planning environmental studies, particularly in setting times to monitor breath in studies of the variation with time of body burden. Improvements in breath methods have made it possible to study short-term peak exposure situations such as filling a gas tank or taking a shower in contaminated water. PMID:8933027

  9. The analysis of components that lead to increased work of breathing in chronic obstructive pulmonary disease patients

    PubMed Central

    Chen, Sibei; Li, Ying; Zheng, Zeguang; Luo, Qun

    2016-01-01

    Background This study is to explore the components and related mechanism responsible for the increase of work of breathing (WB) in chronic obstructive pulmonary disease (COPD) patients. Methods Eight COPD patients and eight healthy volunteers were recruited in the study. The rebreathing method was used to increase end-tidal CO2 partial pressure (PetCO2) and stimulate the increase in ventilation (VE). The increase in VE, WB, and changes in the compositions of WB were observed and analyzed. The WB and its components were calculated using the Campbell diagram. Results The inspiratory work (Wi) of breathing, a major component of total work of breathing (Wtot), in the COPD group was significantly higher than the control group during quiet breathing (P<0.05). As the minute VE increased, Wtot and Wi increased in a linear manner, and the slope of increase was significantly higher in the COPD group as compared to the normal group (P<0.05). The analyses of changes in overcoming airway resistance (Wrs) and lung/chest-wall elastance (Wel) indicated that the slope of increase (response to VE increase) of Wrs was not significantly different between the two groups (P>0.05) although the Wrs in the COPD group was always higher than the normal group (P<0.05). However, as the VE increased, the slope of the increase in Wel was significantly higher in the COPD group than the normal group. Work done to overcome the intrinsic PEEP (WPEEPi), a component of the Wel, was not observed in the control group. However, WPEEPi increased gradually as VE increased and accounted for 56% of Wel at the end of rebreathing trial in COPD group. Conclusions Airway resistance was the main cause for increased WB during quiet breathing. As the VE increased, an increase of WPEEPi became an important part of increased WB in COPD patients, so it is important to reduce dynamic hyperinflation in COPD patients. PMID:27621878

  10. The analysis of components that lead to increased work of breathing in chronic obstructive pulmonary disease patients

    PubMed Central

    Chen, Sibei; Li, Ying; Zheng, Zeguang; Luo, Qun

    2016-01-01

    Background This study is to explore the components and related mechanism responsible for the increase of work of breathing (WB) in chronic obstructive pulmonary disease (COPD) patients. Methods Eight COPD patients and eight healthy volunteers were recruited in the study. The rebreathing method was used to increase end-tidal CO2 partial pressure (PetCO2) and stimulate the increase in ventilation (VE). The increase in VE, WB, and changes in the compositions of WB were observed and analyzed. The WB and its components were calculated using the Campbell diagram. Results The inspiratory work (Wi) of breathing, a major component of total work of breathing (Wtot), in the COPD group was significantly higher than the control group during quiet breathing (P<0.05). As the minute VE increased, Wtot and Wi increased in a linear manner, and the slope of increase was significantly higher in the COPD group as compared to the normal group (P<0.05). The analyses of changes in overcoming airway resistance (Wrs) and lung/chest-wall elastance (Wel) indicated that the slope of increase (response to VE increase) of Wrs was not significantly different between the two groups (P>0.05) although the Wrs in the COPD group was always higher than the normal group (P<0.05). However, as the VE increased, the slope of the increase in Wel was significantly higher in the COPD group than the normal group. Work done to overcome the intrinsic PEEP (WPEEPi), a component of the Wel, was not observed in the control group. However, WPEEPi increased gradually as VE increased and accounted for 56% of Wel at the end of rebreathing trial in COPD group. Conclusions Airway resistance was the main cause for increased WB during quiet breathing. As the VE increased, an increase of WPEEPi became an important part of increased WB in COPD patients, so it is important to reduce dynamic hyperinflation in COPD patients.

  11. Phox2b-expressing neurons of the parafacial region regulate breathing rate, inspiration, and expiration in conscious rats.

    PubMed

    Abbott, Stephen B G; Stornetta, Ruth L; Coates, Melissa B; Guyenet, Patrice G

    2011-11-01

    The retrotrapezoid nucleus contains Phox2b-expressing glutamatergic neurons (RTN-Phox2b neurons) that regulate breathing in a CO₂-dependent manner. Here we use channelrhodopsin-based optogenetics to explore how these neurons control breathing in conscious and anesthetized adult rats. Respiratory entrainment (pacing) of breathing frequency (fR) was produced over 57% (anesthetized) and 28% (conscious) of the natural frequency range by burst activation of RTN-Phox2b neurons (3-8 × 0.5-20 ms pulses at 20 Hz). In conscious rats, pacing under normocapnic conditions increased tidal volume (V(T)) and each inspiration was preceded by active expiration, denoting abdominal muscle contraction. During long-term pacing V(T) returned to prestimulation levels, suggesting that central chemoreceptors such as RTN-Phox2b neurons regulate V(T) partly independently of their effect on fR. Randomly applied light trains reset the respiratory rhythm and shortened the expiratory phase when the stimulus coincided with late-inspiration or early-expiration. Importantly, continuous (20 Hz) photostimulation of the RTN-Phox2b neurons and a saturating CO₂ concentration produced similar effects on breathing that were much larger than those elicited by phasic RTN stimulation. In sum, consistent with their anatomical projections, RTN-Phox2b neurons regulate lung ventilation by controlling breathing frequency, inspiration, and active expiration. Adult RTN-Phox2b neurons can entrain the respiratory rhythm if their discharge is artificially synchronized, but continuous activation of these neurons is much more effective at increasing lung ventilation. These results suggest that RTN-Phox2b neurons are no longer rhythmogenic in adulthood and that their average discharge rate may be far more important than their discharge pattern in driving lung ventilation.

  12. Don't Cross the (Tidal) Streams

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-09-01

    In a tidal disruption event (TDE), an unfortunate star passes too close to a dormant supermassive black hole (BH) and gets torn apart by tidal forces, feeding the BH for a short time. Oddly, were not finding nearly as many TDEs typically detected due to their distinctive observational signatures as theory says we should. A recent study suggests that we might be missing many of these events, due to the way the streams of shredded stars fall onto the BHs.Signatures of ShreddingWhen a BH tears a star apart, the stars material is stretched out into whats known as a tidal stream. That stream continues on a trajectory around the BH, with roughly half the material eventually falling back on the BH, whipping around it in a series of orbits. Where those orbits intersect each other, the material smashes together and circularizes, forming a disk that then accretes onto the BH.What does a TDE look like? We dont observe anything until after the tidal streams collide and the material begins to accrete onto the BH. At that point we observe a sudden peak in luminosity, which then gradually decreases (scaling roughly as time-5/3) as the tail end of whats left of the star accretes and the BHs food source eventually runs out.So why have we only been observing about a tenth as many TDEs as theory predicts we should see? By studying the structure of tidal streams in TDEs, James Guillochon (Harvard-Smithsonian Center for Astrophysics) and Enrico Ramirez-Ruiz (UC Santa Cruz) have found a potential reason and the culprit is general relativity.Dark YearsThe authors run a series of simulations of TDEs around black holes of varying masses and spins to see what form the resulting tidal streams take over time. They find that precession of the tidal stream due to the BHs gravitational effects changes how the stream interacts with itself, and therefore what we observe. Some cases behave like what we expect for whats currently considered a typical TDE but some dont.Example from simulations of a

  13. End tidal carbon dioxide monitoring in prehospital and retrieval medicine: a review

    PubMed Central

    Donald, M J; Paterson, B

    2006-01-01

    End tidal carbon dioxide (ETCO2) monitoring is the non‐invasive measurement of exhaled CO2. The Intensive Care Society guidelines include (ETCO2) monitoring as one of the objective standards required for monitoring patients in transport, and the American Heart Association recommends that all intubations must be confirmed by some form of ETCO2 measurement. The physiological principles and technology underlying ETCO2 measurement and the clinical indication for its use in the prehospital environment are reviewed. ETCO2 monitoring has been widely established in the prehospital environment and is of particular use for verification of endotracheal tube placement. It is non‐invasive and easy to apply to breathing circuits. The units now available are compact and rugged, with extended battery operating times, which are ideally suited for prehospital use and should be considered as an essential item for advanced airway management. PMID:16921096

  14. Circadian rhythm of breath hydrogen in young women.

    PubMed

    Kagaya, M; Iwata, M; Toda, Y; Nakae, Y; Kondo, T

    1998-08-01

    Breath hydrogen levels, which reflect colonic fermentation of undigested starches, are usually low in the fasted state. Fasting levels of breath hydrogen are important for estimation of oro-cecal transit time and diagnosis of lactase deficiency. In young women, however, fasting levels of breath hydrogen are high. To clarify the reason for this, we studied the circadian pattern of breath hydrogen and the effect of alpha-D-galactosidase on fasting breath hydrogen in one study, and the effect of sleep deprivation on fasting breath hydrogen in another study, in 13 women students aged 21-23 years. In the first study, two breath samples were collected, one in the evening and the other the next morning. On another occasion, alpha-D-galactosidase was given before dinner and breath samples were collected the next morning. In the second study, the circadian rhythm of breath hydrogen was assessed for 3 days and the subjects were deprived of sleep on the second night. Breath samples were collected every 30 min, except during the second night when samples were collected at 1-h intervals. Fasting breath hydrogen was 24 +/- 3.9 ppm (mean +/- SE), which did not differ from the value for the previous night. Alpha-D-galactosidase significantly decreased fasting breath hydrogen levels, to 17 +/- 2.4 ppm (P < 0.05). There was a clear circadian pattern of breath hydrogen, high in the morning and decreasing to the nadir by 16:00. After dinner, the level increased again and stayed high during the night. Sleep deprivation did not affect fasting levels of breath hydrogen. High fasting breath hydrogen levels in young women followed a circadian pattern and this may have been due, in part, to an high intake of dietary fiber on the previous day. PMID:9719227

  15. Tidal Marshes: The Boundary between Land and Ocean.

    ERIC Educational Resources Information Center

    Gosselink, James

    An overview of the ecology of the tidal marshes along the gulf coast of the United States is presented. The following topics are included: (1) the human impact on tidal marshes; (2) the geologic origins of tidal marshes; (3) a description of the physical characteristics and ecosystem of the marshlands; (4) a description of the marshland food chain…

  16. How Tidal Forces Cause Ocean Tides in the Equilibrium Theory

    ERIC Educational Resources Information Center

    Ng, Chiu-king

    2015-01-01

    We analyse why it is erroneous to think that a tidal bulge is formed by pulling the water surface directly up by a local vertical tidal force. In fact, ocean tides are caused by the global effect of the horizontal components of the tidal forces.

  17. Tidal stress triggering of earthquakes in Southern California

    NASA Astrophysics Data System (ADS)

    Bucholc, Magda; Steacy, Sandy

    2016-05-01

    We analyse the influence of the solid Earth tides and ocean loading on the occurrence time of Southern California earthquakes. For each earthquake, we calculate tidal Coulomb failure stress and stress rate on a fault plane that is assumed to be controlled by the orientation of the adjacent fault. To reduce bias when selecting data for testing the tide-earthquake relationship, we create four earthquake catalogues containing events within 1, 1.5, 2.5 and 5 km of nearest faults. We investigate the difference in seismicity rates at times of positive and negative tidal stresses/stress rates given three different cases. We consider seismicity rates during times of positive versus negative stress and stress rate, as well as 2 and 3 hr surrounding the local tidal stress extremes. We find that tidal influence on earthquake occurrence is found to be statistically non-random only in close proximity to tidal extremes meaning that magnitude of tidal stress plays an important role in tidal triggering. A non-random tidal signal is observed for the reverse events. Along with a significant increase in earthquake rates around tidal Coulomb stress maxima, the strength of tidal correlation is found to be closely related to the amplitude of the peak tidal Coulomb stress (τp). The most effective tidal triggering is found for τp ≥ 1 kPa, which is much smaller than thresholds suggested for static and dynamic triggering of aftershocks.

  18. Precise mimicking of exercise hyperpnea to investigate the oxygen cost of breathing.

    PubMed

    Dominelli, P B; Render, J N; Molgat-Seon, Y; Foster, G E; Sheel, A W

    2014-09-15

    The oxygen cost of exercise hyperpnea (V˙(O2 RM)) has been quantified using a variety of techniques with inconsistent findings. Between-study variation relates to poor control of breathing patterns and lung mechanics. We developed a methodology allowing precise matching of exercising WOB in order to estimate V˙(O2 RM). Thirteen healthy young subjects (7 male) completed an incremental cycle exercise test, familiarization and experimental days where exercise hyperpnea was mimicked. On experimental days, feedback of exercise flow, volume and the respiratory pressures were provided while end-tidal CO2 was kept at exercise levels during each 5-min trial. Minute ventilation levels between 50 and 100% maximum were mimicked 3-5 times. The r(2) between exercise and mimic trails was 0.99 for frequency, tidal volume and minute ventilation; 0.86 for esophageal pressure swings and 0.93 for WOB. The coefficient of variation for (V˙(O2) averaged 4.3, 4.4 and 5.7% for 50, 75 and 100% ventilation trials. When WOB and other respiratory parameters are tightly controlled, the V˙(O2 RM) can be consistently estimated.

  19. Effect of ozone on breathing in dogs: vagal and nonvagal mechanisms

    SciTech Connect

    Sasaki, K.; Nadel, J.A.; Hahn, H.L.

    1987-01-01

    We exposed two awake dogs with a chronic tracheostomy and the cervical vagus nerves exteriorized in skin loops to 1.0 ppm of ozone (O/sub 3/) for 2 h at intervals of 4 wk. We measured ventilatory variables before and after O/sub 3/ exposure during rest and exercise before and after vagal block. We compared the effects of vagal blockade, exercise, and O/sub 3/ on the primary determinants of breathing pattern (VT/TI, VT/TE, TI, and TE) in each of three conditions: base line (steady state), during hypercapnia, and after inhalation of 1% histamine. Under base-line conditions, O/sub 3/ increased respiratory rate and decreased tidal volume (VT) by shortening time of expiration (TE) and time of inspiration (TI) without affecting VT/TI, an indicator of the neural drive to breathing. During progressive hypercapnia, O/sub 3/ shortened TE and TI by effects both on tonic (nonvolume-related) and on phasic (volume-related) vagal inputs, and only the latter were prevented completely by cooling of the vagus nerves. Histamine-induced tachypnea was increased by O/sub 3/ and was totally blocked by cooling the vagus nerves. It was concluded that O/sub 3/ shortens the timing of respiration without increasing ventilatory drive, shortens TI and TE through vagal and nonvagal pathways, increases tonic nonvagal and phasic vagal inputs, and stimulates more than one vagal fiber type.

  20. Aerosol Deposition in the Human Respiratory Tract Breathing Air and 80:20 Heliox

    PubMed Central

    DARQUENNE, CHANTAL; PRISK, G. KIM

    2005-01-01

    Aerosol mixing resulting from turbulent flows is thought to be an important mechanism of deposition in the upper respiratory tract (URT). Since turbulence levels are a function of gas density, the use of a low density carrier gas would be expected to reduce deposition in the URT. We measured aerosol deposition in the respiratory tract of 8 healthy subjects using both air and heliox, a low density gas mixture containing 80% helium and 20% oxygen, as the carrier gas. The subjects breathed 0.5, 1, and 2 μm-diameter monodisperse polystyrene latex particles from a reservoir at a constant flow rate (~450 mL/sec) and tidal volume (~900 mL). Aerosol concentration and flow rate were measured at the mouth using a photometer and a pneumotachograph, respectively. Deposition was 17.0%, 20.3%, and 38.9% in air and 16.8%, 18.5%, and 36.9% in heliox for 0.5, 1, and 2 μm-diameter particles, respectively. There was a small but statistically significant decrease in deposition when using heliox compared to air for 1 and 2 μm-diameter particles (p < 0.05). While it could not be directly measured from these data, it is likely that when breathing heliox instead of air, deposition is reduced in the URT and increased in the small airways and alveoli. PMID:15625820

  1. Attenuated ventilatory responses to hypercapnia and hypoxia in assisted breath-hold drivers (Funado).

    PubMed

    Masuda, Y; Yoshida, A; Hayashi, F; Sasaki, K; Honda, Y

    1982-01-01

    The steady-state ventilatory responses to hypercapnia and hypoxia in 7 assisted breath-hold divers (Funado) were compared with those in 7 normal sedentary controls. Ventilatory response to hypercapnia was measured from the slope of the hyperoxic VN-PETCO2 line, where VN was normalized minute ventilation using the allometric coefficient and PETCO2 end-Tidal PCO2. The slope of this line in the Funado (1.48 +/- 0.54 liters . min-1 . Torr-1) was significantly less than in the control (2.70 +/- 1.08 liters . min-1 . Torr-1) (p less than 0.025). On the other hand, hypoxic sensitivity estimated by hyperbolic and exponential mathematical equations was not found to be significantly different between the two groups, although estimated increments in ventilation using the hyperbolic equation exhibited significantly lower response in the Funado than in the control only when PETO2 decreased lower than 50 Torr (p less than 0.05). These findings in the Funado were different from our previous observations obtained in unassisted breath-hold divers (Kachido), in whom no obvious attenuations in CO2 sensitivity were seen. This difference was assumed to be derived from more hypercapnic and hypoxic conditions produced in the Funado than in the Kachido during diving activities.

  2. Large tidal currents near Bear Island and related tidal energy losses from the North Atlantic

    NASA Astrophysics Data System (ADS)

    Huthnance, John M.

    1981-01-01

    Independent series of current meter measurements between northern Norway and Bear Island (19°E, 74 1/2° N) by MAFF Fisheries Laboratory, Lowestoft in 1972 and the Norwegian River and Harbour Laboratory in 1978 both show a ten-fold increase in diurnal tidal currents near Bear Island. The increase appears to be due partly to excitation of a topographic mode of natural frequency less than the tidal constituent K1. Part of the increase is also due simply to the shallower water near Bear Island and is shared by the semi-diurnal tidal currents. Tidal energy fluxes out of the Norwegian Sea total about 5 × 10 10 W between Norway and Bear Island and 6 × 10 10 W between Bear Island and Greenland, in contrast with the observational estimate 7 × 10 10 W entering the Norwegian Sea between Scotland and Iceland.

  3. Modelling the far field hydro-environmental impacts of tidal farms - A focus on tidal regime, inter-tidal zones and flushing

    NASA Astrophysics Data System (ADS)

    Nash, S.; O'Brien, N.; Olbert, A.; Hartnett, M.

    2014-10-01

    The introduction of tidal stream turbines into water bodies can have an impact on the environment due to changes in the hydrodynamic flow fields resulting from the extraction of energy by the tidal turbines. Water levels, tidal currents and flushing characteristics could potentially be significantly altered with the introduction of tidal turbine farms, which could lead to possible loss of habitat and a change in the tidal regime. Therefore, planning of tidal turbines field deployments must take into account possible hydro-environmental impacts. This paper describes research undertaken by the authors in the Shannon Estuary to predict changes in the tidal regime and flushing characteristics, with the introduction of tidal turbine farms of different array configurations. The model was simulated using a 2D hydrodynamic model that was modified to incorporate the effects of tidal turbine fields. Water levels are shown to have been affected with the inclusion of turbines, especially in areas upstream of the turbine farm where inter-tidal zones could become predominately inundated resulting in loss of habitat in the estuary. Flushing parameters were also shown to be altered with the inclusion of turbines, with residence time shown to be increased, which could change pollutant transport in the region.

  4. Tidal Dynamics of Transiting Extrasolar Planetary Systems

    NASA Astrophysics Data System (ADS)

    Fabrycky, Daniel C.

    2008-05-01

    The transits of extrasolar planets have revealed a wealth of information about their structures and atmospheres. Because of increased transit likelihood, these planets have small semi-major axes; therefore the planets we know the best are those which are tidally evolved. Transiting planets have not yet been found in multiple-planet systems, but will eventually be an excellent probe of their dynamics. This talk addresses both sides of the coin: theories of tidal dynamics on the one side, clever observations to constrain those theories on the other. On the theory side: Small orbits may be established via eccentricity pumping by a third body (e.g., Kozai cycles) plus tidal dissipation; (b) Oblique spins (Cassini states) may be created and maintained through a secular resonance between orbital precession and spin precession; and (c) Second planets may evolve out of coorbital configurations (near Lagrange points) and mean motion resonance (e.g., the Laplace resonance among Jupiter's satellites) by tidal dissipation. On the observation side: (a) Spectroscopic transit measurements assess the spin orientation of the host star relative to the orbit of the transiting planet; (b) Transit timing measurements can discover second planets and characterize the dynamics of resonant planetary systems; (c) The instantaneous orbital configuration of two-planet systems can indicate the precession rate of the transiting planet, yielding its Love number and probing its internal structure. I gratefully acknowledge funding by the Michelson Fellowship, supported by the National Aeronautics and Space Administration and administered by the Michelson Science Center.

  5. 2008 NWFSC Tidal Freshwater Genetics Results

    SciTech Connect

    David Teel

    2009-05-01

    Genetic Analysis of Juvenile Chinook Salmon for inclusion in 'Ecology of Juvenile Salmon in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2008. Annual Report to Bonneville Power Administration, Contract DE-AC05-76RL01830.'

  6. Tidal Energy Dissipation from Topex/Poseidon

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Egbert, G. D.; Smith, David E. (Technical Monitor)

    2000-01-01

    In a recent paper ({\\it Nature, 405,} 775, 2000) we concluded that 25 to 30\\% of the ocean's tidal energy dissipation, or about 1 terawatt, occurs in the deep ocean, with the remaining 2.6 TW in shallow seas. The physical mechanism for deep-ocean dissipation is apparently scattering of the surface tide into internal modes; Munk and Wunsch have suggested that this mechanism may provide half the power needed for mixing the deep-ocean. This paper builds further evidence for $1\\pm 0.2$ TW of deep-ocean dissipation. The evidence is extracted from tidal elevations deduced from seven years of Topex/Poseidon satellite altimeter data. The dissipation rate Is formed as a balance between the rate of working by tidal forces and the energy flux divergence. While dynamical assumptions are required to compute fluxes, area integrals of the energy balance are, owing to the tight satellite constraints, remarkably insensitive to these assumptions. A large suite of tidal solutions based on a wide range of dynamical assumptions, on perturbations to bathymetric models, and on simulated elevation data are used to assess this sensitivity. These and Monte Carlo error fields from a generalized inverse model are used to establish error uncertainties.

  7. Estuaries and Tidal Marshes. Habitat Pac.

    ERIC Educational Resources Information Center

    Fish and Wildlife Service (Dept. of Interior), Washington, DC.

    This educational packet consists of an overview, three lesson plans, student data sheets, and a poster. The overview examines estuaries and tidal or salt marshes by discussing the plants and animals in these habitats, marsh productivity, benefits and management of the habitats, historical aspects, and development and pollution. A glossary and list…

  8. Tidal deformation, Orbital Dynamics and JIMO

    NASA Astrophysics Data System (ADS)

    Ratcliff, J. T.; Wu, X.; Williams, J. G.

    2003-12-01

    Observations of Europa, Ganymede and Callisto obtained from encounters by the Galileo spacecraft strongly suggest the possibility of liquid oceans under the icy shells of these Jovian satellites. The strong tidal environments in which these moons are found and the fact that a planetary body with internal fluid undergoes greater deformation than an otherwise solid body make a compelling case for using tidal observations as a method for ocean detection. Given the high degree of uncertainty in our knowledge of the interiors of these moons, a comprehensive geodetic program measuring different physical signatures related to tidal deformation and interior structure is preferred to using separate and various interior parameters that may not be as closely tied to actual measurable quantities. Potential and displacement tidal Love numbers, libration amplitudes of the surface ice shell and rocky mantle, static topography and gravity fields and other quantities should all be included in the measurement objectives. Many geodetic techniques rely heavily upon orbital positions of the spacecraft. Their accurate determination depend on factors such as the orbital configuration, the gravity fields of the icy moons, as well as the duration and geometry of tracking. Given the competing science, engineering and planetary protection demands, orbital accuracy subject to constraints has become a critical mission design issue. Orbit determination simulations and covariance analyses will be used to investigate the achievable accuracies of spacecraft position and geodetic signatures under different orbital and tracking scenarios.

  9. The Tidal Filament of NGC 4660

    NASA Astrophysics Data System (ADS)

    Kemp, S. N.; Martínez-Robles, C.; Márquez-Lugo, R. A.; Zepeda-García, D.; Franco-Hernández, R.; Nigoche-Netro, A.; Ramos-Larios, G.; Navarro, S. G.; Corral, L. J.

    2016-10-01

    NGC 4660, in the Virgo cluster, is a well-studied elliptical galaxy which has a strong disk component (D/T approximately 0.2–0.3). The central regions, including the disk component, have stellar populations approximately 12–13 Gyr in age, based on SAURON studies. However, we report the discovery of a long, narrow tidal filament associated with the galaxy, as seen in deep co-added Schmidt plate images and deep CCD frames, implying that the galaxy has undergone a tidal interaction and merger within the last few Gyr. The relative narrowness of the filament implies a wet merger with at least one spiral galaxy involved, but the current state of the system shows little evidence of such. However, a two-component photometric fit using GALFIT shows much bluer B-V colors for the disk component than for the elliptical component, which may represent a residual trace of enhanced star formation in the disk caused by the interaction 1–2 Gyr ago. There are brighter concentrations within the filament that resemble tidal dwarf galaxies, although they are at least 40 times fainter. These concentrations may represent faint, evolved versions of those galaxies. A previously detected stripped satellite galaxy south of the nucleus seen in our residual image may imply that the filament is a tidal stream produced by perigalactic passages of this satellite.

  10. Motivational processes and behavioral inhibition in breath holding.

    PubMed

    Alpher, V S; Blanton, R L

    1991-01-01

    Large individual differences in breathing performance have made it difficult to investigate the effects of psychological variables on respiratory parameters. This study uses an experimental approach to investigating the effects of attentional and motivational factors on breath-holding span in humans. The effects of shock threat (negative incentive), monetary reward (positive incentive), and mantra meditation (attentional control) on breath-holding span at functional residual capacity (FRC) were compared. Based on Jeffrey Gray's (1975, 1987) theory of behavioral inhibition, it was predicted that shock threat would extend FRC breath holding. Breath holding was increased under the shock threat condition but not under the monetary reward or mantra meditation conditions.

  11. Possibility of oscillatory tidal heating of Enceladus

    NASA Astrophysics Data System (ADS)

    Shoji, D.; Hussmann, H.; Sohl, F.; Kurita, K.

    2012-12-01

    Enceladus radiates ~16 GW of heat from its surface [1]. One efficient heat source of Enceladus is tidal heating which is maintained by the orbital resonance with Dione. However, assuming that the current eccentricity of Enceladus is in equilibrium with the resonance, tidal heating can generate only 1.1 GW of heat [2]. In the case of a non-equilibrium state, tidal heating rate and eccentricity evolve by interacting with each other. For homogeneous model of Enceladus, corresponding coupling calculations have been conducted by Meyer and Wisdom [3]. In their calculations, generated heat and eccentricity reach equilibrium state soon. In this work, we have performed coupling calculation among tidal heating rate, eccentricity and the interior structure of Enceladus. We constructed spherical shell Maxwell model for simplicity. Conventionally, dissipation factor (Q-value) of Saturn is estimated to more than 18,000 [2]. However, the latest observation implies a Q-value of Saturn that is one of order of magnitude less than conventional values [4]. We performed the calculation with different values of the Saturnian dissipation factor. In addition to the tidal heat, we took 7 GW of shear heat into consideration as an additional heat source[5]. In our calculation, if water-ice mixture (~10^9 Pa s in viscosity) exists between convective ice and silicate core instead of liquid ocean, eccentricity and heating rate oscillate with an 50-million-years cycle when the Q-value of Saturn is assumed around 3800. Minimum value of eccentricity is 0.005, which is comparable to the current value (0.0047). Generated tidal heat oscillates between 3 GW and 10 GW. Combined with shear heat, 17 GW of heat is generated at maximum. Although conditions for oscillatory heating are hard to fulfill and more consideration is needed, current large heat radiation of Enceladus may be remnant of episodically large tidal heating. Enceladus has divergent surface conditions, which might be related to episodic

  12. TIDAL EVOLUTION OF CLOSE-IN PLANETS

    SciTech Connect

    Matsumura, Soko; Rasio, Frederic A.; Peale, Stanton J.

    2010-12-20

    Recent discoveries of several transiting planets with clearly non-zero eccentricities and some large obliquities started changing the simple picture of close-in planets having circular and well-aligned orbits. The two major scenarios that form such close-in planets are planet migration in a disk and planet-planet interactions combined with tidal dissipation. The former scenario can naturally produce a circular and low-obliquity orbit, while the latter implicitly assumes an initially highly eccentric and possibly high-obliquity orbit, which are then circularized and aligned via tidal dissipation. Most of these close-in planets experience orbital decay all the way to the Roche limit as previous studies showed. We investigate the tidal evolution of transiting planets on eccentric orbits, and find that there are two characteristic evolution paths for them, depending on the relative efficiency of tidal dissipation inside the star and the planet. Our study shows that each of these paths may correspond to migration and scattering scenarios. We further point out that the current observations may be consistent with the scattering scenario, where the circularization of an initially eccentric orbit occurs before the orbital decay primarily due to tidal dissipation in the planet, while the alignment of the stellar spin and orbit normal occurs on a similar timescale to the orbital decay largely due to dissipation in the star. We also find that even when the stellar spin-orbit misalignment is observed to be small at present, some systems could have had a highly misaligned orbit in the past, if their evolution is dominated by tidal dissipation in the star. Finally, we also re-examine the recent claim by Levrard et al. that all orbital and spin parameters, including eccentricity and stellar obliquity, evolve on a similar timescale to orbital decay. This counterintuitive result turns out to have been caused by a typo in their numerical code. Solving the correct set of tidal

  13. Relativistic tidal properties of neutron stars

    SciTech Connect

    Damour, Thibault; Nagar, Alessandro

    2009-10-15

    We study the various linear responses of neutron stars to external relativistic tidal fields. We focus on three different tidal responses, associated to three different tidal coefficients: (i) a gravito-electric-type coefficient G{mu}{sub l}=[length]{sup 2l+1} measuring the lth-order mass multipolar moment GM{sub a{sub 1}}{sub ...a{sub I}} induced in a star by an external lth-order gravito-electric tidal field G{sub a{sub 1}}{sub ...a{sub I}}; (ii) a gravito-magnetic-type coefficient G{sigma}{sub l}=[length]{sup 2l+1} measuring the lth spin multipole moment GS{sub a{sub 1}}{sub ...a{sub I}} induced in a star by an external lth-order gravito-magnetic tidal field H{sub a{sub 1}}{sub ...a{sub I}}; and (iii) a dimensionless 'shape' Love number h{sub l} measuring the distortion of the shape of the surface of a star by an external lth-order gravito-electric tidal field. All the dimensionless tidal coefficients G{mu}{sub l}/R{sup 2l+1}, G{sigma}{sub l}/R{sup 2l+1}, and h{sub l} (where R is the radius of the star) are found to have a strong sensitivity to the value of the star's 'compactness'c{identical_to}GM/(c{sub 0}{sup 2}R) (where we indicate by c{sub 0} the speed of light). In particular, G{mu}{sub l}/R{sup 2l+1}{approx}k{sub l} is found to strongly decrease, as c increases, down to a zero value as c is formally extended to the 'black hole (BH) limit'c{sup BH}=1/2. The shape Love number h{sub l} is also found to significantly decrease as c increases, though it does not vanish in the formal limit c{yields}c{sup BH}, but is rather found to agree with the recently determined shape Love numbers of black holes. The formal vanishing of {mu}{sub l} and {sigma}{sub l} as c{yields}c{sup BH} is a consequence of the no-hair properties of black holes. This vanishing suggests, but in no way proves, that the effective action describing the gravitational interactions of black holes may not need to be augmented by nonminimal worldline couplings.

  14. Ice rheology and tidal heating of Enceladus

    NASA Astrophysics Data System (ADS)

    Shoji, D.; Hussmann, H.; Kurita, K.; Sohl, F.

    2013-09-01

    For the saturnian satellite Enceladus, the possible existence of a global ocean is a major issue. For the stability of an internal ocean, tidal heating is suggested as an effective heat source. However, assuming Maxwell rheology ice, it has been shown that a global scale ocean on Enceladus cannot be maintained (Roberts, J.F., Nimmo, F. [2008]. Icarus 194, 675-689). Here, we analyze tidal heating and the stability of a global ocean from the aspect of anelastic behavior. The Maxwell model is the most typical and widely used viscoelastic model. However, in the tidal frequency domain, energy is also dissipated by the anelastic response involving time-dependent or transient creep mechanisms, which is different from the viscoelastic response caused by steady-state creep. The Maxwell model cannot adequately address anelasticity, which has a large effect in the high viscosity range. Burgers and Andrade models are suggested as suitable models for the creep behavior of ice in the frequency domain. We calculate tidal heating in the ice layer and compare it with the radiated heat assuming both convection and conduction of the ice layer. Though anelastic behavior increases the heating rate, it is insufficient to maintain a global subsurface ocean if the ice layer is convecting, even though a wide parameter range is taken into account. One possibility to maintain a global ocean is that Enceladus’ ice shell is conductive and its tidal response is similar to that of the Burgers body with comparatively small transient shear modulus and viscosity. If the surface ice with large viscosity is dissipative by anelastic response, the heat produced in the ice layer would supersede the cooling rate and a subsurface ocean could be maintained without freezing.

  15. Tidally Induced Bars of Galaxies in Clusters

    NASA Astrophysics Data System (ADS)

    Łokas, Ewa L.; Ebrová, Ivana; del Pino, Andrés; Sybilska, Agnieszka; Athanassoula, E.; Semczuk, Marcin; Gajda, Grzegorz; Fouquet, Sylvain

    2016-08-01

    Using N-body simulations, we study the formation and evolution of tidally induced bars in disky galaxies in clusters. Our progenitor is a massive, late-type galaxy similar to the Milky Way, composed of an exponential disk and a Navarro-Frenk-White dark matter halo. We place the galaxy on four different orbits in a Virgo-like cluster and evolve it for 10 Gyr. As a reference case, we also evolve the same model in isolation. Tidally induced bars form on all orbits soon after the first pericenter passage and survive until the end of the evolution. They appear earlier, are stronger and longer, and have lower pattern speeds for tighter orbits. Only for the tightest orbit are the properties of the bar controlled by the orientation of the tidal torque from the cluster at pericenter. The mechanism behind the formation of the bars is the angular momentum transfer from the galaxy stellar component to its halo. All of the bars undergo extended periods of buckling instability that occur earlier and lead to more pronounced boxy/peanut shapes when the tidal forces are stronger. Using all simulation outputs of galaxies at different evolutionary stages, we construct a toy model of the galaxy population in the cluster and measure the average bar strength and bar fraction as a function of clustercentric radius. Both are found to be mildly decreasing functions of radius. We conclude that tidal forces can trigger bar formation in cluster cores, but not in the outskirts, and thus can cause larger concentrations of barred galaxies toward the cluster center.

  16. Breathing in fetal lambs: the effect of brain stem section.

    PubMed

    Dawes, G S; Gardner, W N; Johnston, B M; Walker, D W

    1983-02-01

    The effects of section of the brain stem caudally (through the upper pons or mid-collicular) or rostrally (through the caudal hypothalamus or anterior commissure-suprachiasmatic nucleus) were studied in fetal lambs from 118 days gestation, after recovery in utero. In lambs sectioned caudally, breathing movements and electrocortical activity were dissociated. After some days recovery breathing tended to become continuous, with an abnormal prolongation of inspiratory time. Isocapnic hypoxia caused an increase in the rate and amplitude of breathing. After carotid denervation hypoxia still caused an increase in the amplitude of breathing. In lambs sectioned rostrally, there was also dissociation between breathing movements and electrocortical activity. Breathing remained episodic, with an incidence similar to that of intact fetal lambs. In two lambs after 10 days of recovery the breathing and electrocortical rhythms returned, from time to time, to their normal phasic relationship. Isocapnic hypoxia caused a diminution or arrest of breathing, as in intact lambs. The cardiovascular effects of transection were examined. Baroreflex sensitivity was normal in those lambs sectioned caudally and enhanced in those sectioned rostrally. It is concluded first that as a result of rostral section, independent episodic rhythms of fetal breathing and electrocortical activity can be dissociated. Secondly, moderate isocapnic hypoxia causes arrest of fetal breathing indirectly, requiring the integrity of a suprapontine mechanism. And thirdly, after caudal section of the brain stem, hypoxia causes enhancement of fetal breathing efforts, independently of the carotid chemoreceptors. Possible mechanisms are discussed. PMID:6875894

  17. Tidal Tales: Comparison of Star Formation in Tidal Tails of Minor Mergers

    NASA Astrophysics Data System (ADS)

    Knierman, Karen A.; Scowen, Paul A.; Groppi, Christopher E.

    2016-01-01

    While major mergers and their tidal debris are well studied, they are less common than minor mergers (mass ratios <0.3) and likely played a role in forming most large galaxies, including the Milky Way. Tidal debris regions have large reservoirs of neutral gas but a lower gas density and may have higher turbulence. Star formation tracers such as young star cluster populations, star cluster complexes, and H-alpha, CO, molecular hydrogen, and CII emission were studied to determine the different factors that may influence star formation in tidal debris. These tracers were compared to the reservoirs of gas available for star formation to estimate the star formation efficiency (SFE). In our pilot study using two of the sample of 15 minor mergers, we find that the star formation rate (SFR) of minor merger tidal debris can reach up to 50% of the total star formation in the system which is comparable to prior simulations of star formation in major mergers. The SFE of tidal tails in minor mergers can range over orders of magnitude on both local and global scales. From the tidal debris environments in this study, this variance appears to stem from the formation conditions of the debris. Further work on the 13 additional minor mergers in this sample will shed more light on the factors influencing star formation in low density environments.

  18. Tidal Tales of Minor Mergers: Star Formation in Minor Merger Tidal Tails

    NASA Astrophysics Data System (ADS)

    Knierman, Karen; Scowen, P.; Groppi, C.; Veach, T.; Knezek, P. M.; Mullan, B.; Konstanopoulos, I. S.; Charlton, J. C.; Jansen, R.; Wehner, E.

    2014-07-01

    While major mergers and their tidal debris are well studied, they are less common than minor mergers and likely played a role in forming most large galaxies, including the Milky Way. Tidal debris regions have large amounts of neutral gas but a lower gas density and may have higher turbulence.Star formation tracers such as young star cluster populations and Halpha, CO, and CII emission were studied to determine the different factors that may influence star formation in tidal debris. These tracers were compared to the reservoirs of gas available for star formation to estimate the star formation efficiency (SFE). The SFR of tidal debris can reach up to 50% of the total star formation in the system. The SFE of tidal tails in minor mergers can range over orders of magnitude on both local and global scales. From the tidal debris environments in this study, this variance appears to stem from the formation conditions of the debris. A large survey with TMT as well as the continuing programs of ALMA and the EVLA can provide a larger sample of environments to study the threshold for star formation and can inform star formation models, particularly at low densities.

  19. Maximal breath-holding time and immediate tissue CO2 storage capacity during head-out immersion in humans.

    PubMed

    Chang, L P; Lundgren, C E

    1996-01-01

    This study tested three possible mechanisms that could explain the prolonged breath-holds (BH) previously observed in humans during submersion in 35 degrees C (thermoneutral) water, including a reduced metabolism, a decreased CO2 sensitivity, and an increased CO2 storage capacity. During immersed BH (n = 13), maximal BH time was prolonged by 20.3% (P < 0.05), the rate of rise of end tidal partial pressure of carbon dioxide (PETCO2) was slower (P < 0.05) by 31% (compatible with increased CO2 storage capacity), but the breaking-point PETCO2 (CO2 sensitivity) and the rate of decrease of end tidal partial pressure of oxygen (metabolism) were unchanged. During air breathing (n = 5), immersion resulted in a significant decrease in tidal volume (11%), but did not affect O2 uptake, CO2 elimination (VCO2), or respiratory exchange ratio (R). During a 4-min CO2-rebreathing (n = 9), the slope of the hypercapnic ventilatory response curve (CO2 sensitivity index) was unchanged by immersion, but the significantly decreased VCO2, R, and rate of rise in PETCO2 during immersed rebreathing indicated an increase in the acute CO2 storage capacity (SC). The estimated SC (n = 9), based on an assumed cellular respiratory quotient of 0.8, were 0.52 (SEM 0.03) ml.kg-1.mmHg-1 for control and 0.66 (SEM 0.04) ml.kg-1.mmHg-1 for immersion. A proposed mechanism for the increased SC during immersed BH and during immersed rebreathing is that immersion accelerated CO2 redistribution in the body by increasing perfusion to some low-perfused, low-metabolism, and high-capacity tissues, such as resting skeletal muscle. The increased SC during immersion, however, did not correlate with the prolonged BH duration (n = 9, P > 0.05). The mechanism of the latter remains unclear.

  20. Metabolite Content Profiling of Bottlenose Dolphin Exhaled Breath

    PubMed Central

    2014-01-01

    Changing ocean health and the potential impact on marine mammal health are gaining global attention. Direct health assessments of wild marine mammals, however, is inherently difficult. Breath analysis metabolomics is a very attractive assessment tool due to its noninvasive nature, but it is analytically challenging. It has never been attempted in cetaceans for comprehensive metabolite profiling. We have developed a method to reproducibly sample breath from small cetaceans, specifically Atlantic bottlenose dolphins (Tursiops truncatus). We describe the analysis workflow to profile exhaled breath metabolites and provide here a first library of volatile and nonvolatile compounds in cetacean exhaled breath. The described analytical methodology enabled us to document baseline compounds in exhaled breath of healthy animals and to study changes in metabolic content of dolphin breath with regard to a variety of factors. The method of breath analysis may provide a very valuable tool in future wildlife conservation efforts as well as deepen our understanding of marine mammals biology and physiology. PMID:25254551

  1. A new double-tracer gas single-breath washout to assess early cystic fibrosis lung disease.

    PubMed

    Singer, Florian; Stern, Georgette; Thamrin, Cindy; Abbas, Chiara; Casaulta, Carmen; Frey, Urs; Latzin, Philipp

    2013-02-01

    In cystic fibrosis (CF), tests for ventilation inhomogeneity are sensitive but not established for clinical routine. We assessed feasibility of a new double-tracer gas single-breath washout (SBW) in school-aged children with CF and control subjects, and compared SBW between groups and with multiple-breath nitrogen washout (MBNW). Three SBW and MBNW were performed in 118 children (66 with CF) using a side-stream ultrasonic flowmeter setup. The double-tracer gas containing 5% sulfur hexafluoride and 26.3% helium was applied during one tidal breath. Outcomes were SBW phase III slope (SIII(DTG)), MBNW-derived lung clearance index (LCI), and indices of acinar (S(acin)) and conductive (S(cond)) ventilation inhomogeneity. SBW took significantly less time to perform than MBNW. SBW and MBNW were feasible in 109 (92.4%) and 98 (83.0%) children, respectively. SIII(DTG) differed between children with CF and controls, mean±sd was -456.7±492.8 and -88.4±129.1 mg·mol·L(-1), respectively. Abnormal SIII(DTG) was present in 36 (59%) children with CF. SIII(DTG) was associated with LCI (r= -0.58) and S(acin) (r= -0.58), but not with S(cond). In CF, steeply sloping SIII(DTG) potentially reflects ventilation inhomogeneity near the acinus entrance. This tidal SBW is a promising test to assess ventilation inhomogeneity in an easy and fast way. PMID:22599360

  2. Breath Analysis Using Laser Spectroscopic Techniques: Breath Biomarkers, Spectral Fingerprints, and Detection Limits

    PubMed Central

    Wang, Chuji; Sahay, Peeyush

    2009-01-01

    Breath analysis, a promising new field of medicine and medical instrumentation, potentially offers noninvasive, real-time, and point-of-care (POC) disease diagnostics and metabolic status monitoring. Numerous breath biomarkers have been detected and quantified so far by using the GC-MS technique. Recent advances in laser spectroscopic techniques and laser sources have driven breath analysis to new heights, moving from laboratory research to commercial reality. Laser spectroscopic detection techniques not only have high-sensitivity and high-selectivity, as equivalently offered by the MS-based techniques, but also have the advantageous features of near real-time response, low instrument costs, and POC function. Of the approximately 35 established breath biomarkers, such as acetone, ammonia, carbon dioxide, ethane, methane, and nitric oxide, 14 species in exhaled human breath have been analyzed by high-sensitivity laser spectroscopic techniques, namely, tunable diode laser absorption spectroscopy (TDLAS), cavity ringdown spectroscopy (CRDS), integrated cavity output spectroscopy (ICOS), cavity enhanced absorption spectroscopy (CEAS), cavity leak-out spectroscopy (CALOS), photoacoustic spectroscopy (PAS), quartz-enhanced photoacoustic spectroscopy (QEPAS), and optical frequency comb cavity-enhanced absorption spectroscopy (OFC-CEAS). Spectral fingerprints of the measured biomarkers span from the UV to the mid-IR spectral regions and the detection limits achieved by the laser techniques range from parts per million to parts per billion levels. Sensors using the laser spectroscopic techniques for a few breath biomarkers, e.g., carbon dioxide, nitric oxide, etc. are commercially available. This review presents an update on the latest developments in laser-based breath analysis. PMID:22408503

  3. Women candidates for diving with oxygen-enriched gas mixtures have a lower end tidal CO2 than men during moderate exercise.

    PubMed

    Eynan, Mirit; Abramovich, Amir; Arieli, Yehuda

    2013-12-01

    We have previously determined the thresholds for CO2 detection (conscious recognition of elevated CO2) and retention in male divers, beyond which a diving candidate should not continue his diving activity due to an increased risk of CNS oxygen toxicity. The purpose of the present study was to establish whether there is a difference in end tidal PCO2 between male and female divers who use oxygen-enriched gas mixtures. Ventilatory and perceptual responses to variations in inspired CO2 (range 0-42 mm Hg) were assessed during moderate exercise in 18 males and 18 females. End tidal PCO2 was lower in the female divers when breathing oxygen with 42 mm Hg CO2 (58.2±3.0 mm Hg vs. 61.5±4.5 mm Hg, P<0.03). These results suggest that female divers have a lower end tidal CO2 than males when breathing a hyperoxic gas mixture during exercise, which might imply that women are less susceptible to CNS oxygen toxicity than men.

  4. Evaluation of a transportable capnometer for monitoring end-tidal carbon dioxide.

    PubMed

    Hildebrandt, T; Espelund, M; Olsen, K S

    2010-10-01

    We compared a small and transportable Capnometer (EMMA™) with a reference capnometer, the Siesta i TS Anaesthesia. During air-breathing through a facemask, both the EMMA (nine modules) and reference capnometer sampled expired gas simultaneously. A wide range of end-tidal carbon dioxide values were obtained during inhalation of carbon dioxide and voluntary hyperventilation. The median IQR [range] difference between all sets of carbon dioxide values (EMMA - reference) was -0.3 (-0.6 to 0.0 [-1.7 to 1.6] kPa; n = 297) using new batteries, which was statistically significant (p = 0.04) and located to two of the nine EMMAs tested. Using batteries with reduced voltage did not influence the measurements. The 95% CI of the medians of the differences were -0.4 to -0.2. We conclude that the EMMA can slightly under-read the end-tidal carbon dioxide but is generally comparable with a free-standing monitor. The precision of the EMMAs was similar whether new batteries or batteries with reduced voltage were used.

  5. Sleep-disordered breathing and psychiatric disorders.

    PubMed

    Naqvi, Haider A; Wang, David; Glozier, Nicholas; Grunstein, Ronald R

    2014-12-01

    Sleep-disordered breathing, the commonest form of which is obstructive sleep apnoea (OSA) is increasingly recognised as a treatable cause of morbidity. It shares many risk factors with psychiatric disorders including behaviours such as smoking and physical comorbidity. Many symptoms of the two overlap, leaving OSA often undetected and undertreated. In the few studies that assess the two, OSA is commonly comorbid with depression (17-45%) and schizophrenia (up to 55%) and possibly bipolar. There is some limited evidence that treating OSA can ameliorate psychiatric symptoms. Some psychotropics, such as narcotics, cause sleep-disordered breathing (SDB), whilst weight-inducing neuroleptics may exacerbate it. An extreme form of SDB, sudden infant death syndrome (SIDS), is a risk in mothers with substance abuse. Being aware of these common comorbidities may help improve psychiatric patient's treatment and quality of life. PMID:25308389

  6. Weyl magnons in breathing pyrochlore antiferromagnets.

    PubMed

    Li, Fei-Ye; Li, Yao-Dong; Kim, Yong Baek; Balents, Leon; Yu, Yue; Chen, Gang

    2016-01-01

    Frustrated quantum magnets not only provide exotic ground states and unusual magnetic structures, but also support unconventional excitations in many cases. Using a physically relevant spin model for a breathing pyrochlore lattice, we discuss the presence of topological linear band crossings of magnons in antiferromagnets. These are the analogues of Weyl fermions in electronic systems, which we dub Weyl magnons. The bulk Weyl magnon implies the presence of chiral magnon surface states forming arcs at finite energy. We argue that such antiferromagnets present a unique example, in which Weyl points can be manipulated in situ in the laboratory by applied fields. We discuss their appearance specifically in the breathing pyrochlore lattice, and give some general discussion of conditions to find Weyl magnons, and how they may be probed experimentally. Our work may inspire a re-examination of the magnetic excitations in many magnetically ordered systems. PMID:27650053

  7. Weyl magnons in breathing pyrochlore antiferromagnets

    NASA Astrophysics Data System (ADS)

    Li, Fei-Ye; Li, Yao-Dong; Kim, Yong Baek; Balents, Leon; Yu, Yue; Chen, Gang

    2016-09-01

    Frustrated quantum magnets not only provide exotic ground states and unusual magnetic structures, but also support unconventional excitations in many cases. Using a physically relevant spin model for a breathing pyrochlore lattice, we discuss the presence of topological linear band crossings of magnons in antiferromagnets. These are the analogues of Weyl fermions in electronic systems, which we dub Weyl magnons. The bulk Weyl magnon implies the presence of chiral magnon surface states forming arcs at finite energy. We argue that such antiferromagnets present a unique example, in which Weyl points can be manipulated in situ in the laboratory by applied fields. We discuss their appearance specifically in the breathing pyrochlore lattice, and give some general discussion of conditions to find Weyl magnons, and how they may be probed experimentally. Our work may inspire a re-examination of the magnetic excitations in many magnetically ordered systems.

  8. Protective supplied-breathing-air garment

    DOEpatents

    Childers, E.L.; von Hortenau, E.F.

    1982-05-28

    A breathing-air garment for isolating a wearer from hostile environments containing toxins or irritants is disclosed. The garment includes a suit and a separate head-protective enclosure or hood engaging a suit collar in sealing attachment. The hood and suit collar are cylindrically shaped and dimensioned to enable the wearer to withdraw his hands from the suit sleeves to perform manual tasks within the hood interior. Breathing air is supplied from an external air line with an air-delivery hose attached to the hood interior. The hose feeds air into an annular halo-like fiber-filled plenum having spaced discharge orifices attached to the hood top wall. A plurality of air exhaust/check valves located at the suit extremities cooperate with the hood air-delivery system to provide a cooling flow of circulating air from the hood throughout the suit interior. A suit entry seal provided on the suit sealed with an adhesive sealing flap.

  9. Weyl magnons in breathing pyrochlore antiferromagnets

    PubMed Central

    Li, Fei-Ye; Li, Yao-Dong; Kim, Yong Baek; Balents, Leon; Yu, Yue; Chen, Gang

    2016-01-01

    Frustrated quantum magnets not only provide exotic ground states and unusual magnetic structures, but also support unconventional excitations in many cases. Using a physically relevant spin model for a breathing pyrochlore lattice, we discuss the presence of topological linear band crossings of magnons in antiferromagnets. These are the analogues of Weyl fermions in electronic systems, which we dub Weyl magnons. The bulk Weyl magnon implies the presence of chiral magnon surface states forming arcs at finite energy. We argue that such antiferromagnets present a unique example, in which Weyl points can be manipulated in situ in the laboratory by applied fields. We discuss their appearance specifically in the breathing pyrochlore lattice, and give some general discussion of conditions to find Weyl magnons, and how they may be probed experimentally. Our work may inspire a re-examination of the magnetic excitations in many magnetically ordered systems. PMID:27650053

  10. More air-breathing spaceplane projects

    NASA Astrophysics Data System (ADS)

    Holmes, Diane L.

    1989-08-01

    The development and funding of current air-breathing spaceplane projects are discussed. The research considered includes: West Germany's Saenger, the UK's Hotol, the US's NASP, India's hyperplane, and the hypersonic activities of France, Japan, and the USSR. The basic characteristics of a spaceplace are: a reduction in launch costs, reusability, easier ground operations and launch preparation, short turnaround times, horizontal take-off and landing, and reliability and safety. Various types of power-plant concepts for the spaceplane, such as turbojet, ramjet, and scramjet, are described and diagrams are presented. The design of the airframe, aerodynamic heating, payload capacity, and the cost for developing an air-breathing spaceplane are examined. Applications for the spaceplane are proposed.

  11. Breath tests and irritable bowel syndrome.

    PubMed

    Rana, Satya Vati; Malik, Aastha

    2014-06-28

    Breath tests are non-invasive tests and can detect H₂ and CH₄ gases which are produced by bacterial fermentation of unabsorbed intestinal carbohydrate and are excreted in the breath. These tests are used in the diagnosis of carbohydrate malabsorption, small intestinal bacterial overgrowth, and for measuring the orocecal transit time. Malabsorption of carbohydrates is a key trigger of irritable bowel syndrome (IBS)-type symptoms such as diarrhea and/or constipation, bloating, excess flatulence, headaches and lack of energy. Abdominal bloating is a common nonspecific symptom which can negatively impact quality of life. It may reflect dietary imbalance, such as excess fiber intake, or may be a manifestation of IBS. However, bloating may also represent small intestinal bacterial overgrowth. Patients with persistent symptoms of abdominal bloating and distension despite dietary interventions should be referred for H₂ breath testing to determine the presence or absence of bacterial overgrowth. If bacterial overgrowth is identified, patients are typically treated with antibiotics. Evaluation of IBS generally includes testing of other disorders that cause similar symptoms. Carbohydrate malabsorption (lactose, fructose, sorbitol) can cause abdominal fullness, bloating, nausea, abdominal pain, flatulence, and diarrhea, which are similar to the symptoms of IBS. However, it is unclear if these digestive disorders contribute to or cause the symptoms of IBS. Research studies show that a proper diagnosis and effective dietary intervention significantly reduces the severity and frequency of gastrointestinal symptoms in IBS. Thus, diagnosis of malabsorption of these carbohydrates in IBS using a breath test is very important to guide the clinician in the proper treatment of IBS patients. PMID:24976698

  12. Air breathing direct methanol fuel cell

    DOEpatents

    Ren, Xiaoming; Gottesfeld, Shimshon

    2002-01-01

    An air breathing direct methanol fuel cell is provided with a membrane electrode assembly, a conductive anode assembly that is permeable to air and directly open to atmospheric air, and a conductive cathode assembly that is permeable to methanol and directly contacting a liquid methanol source. Water loss from the cell is minimized by making the conductive cathode assembly hydrophobic and the conductive anode assembly hydrophilic.

  13. Breath Analysis in Pulmonary Arterial Hypertension

    PubMed Central

    Cikach, Frank S.; Tonelli, Adriano R.; Barnes, Jarrod; Paschke, Kelly; Newman, Jennie; Grove, David; Dababneh, Luma; Wang, Sihe

    2014-01-01

    Background: Pulmonary arterial hypertension (PAH) is a progressive and devastating condition characterized by vascular cell proliferation and is associated with several metabolic derangements. We hypothesized that metabolic derangements in PAH can be detected by measuring metabolic by-products in exhaled breath. Methods: We collected breath and blood samples from patients with PAH at the time of right-sided heart catheterization (n = 31) and from healthy control subjects (n = 34). Breath was analyzed by selected ion flow tube-mass spectrometry in predetermined training and validation cohorts. Results: Patients with PAH were 51.5 ± 14 years old, and 27 were women (85%). Control subjects were 38 ± 13 years old, and 22 were women (65%). Discriminant analysis in the training set identified three ion peaks (H3O+29+, NO+56+, and O2+98+) and the variable age that correctly classified 88.9% of the individuals. In an independent validation cohort, 82.8% of the individuals were classified correctly. The concentrations of the volatile organic compounds 2-propanol, acetaldehyde, ammonia, ethanol, pentane, 1-decene, 1-octene, and 2-nonene were different in patients with PAH compared with control subjects. Exhaled ammonia was higher in patients with PAH (median [interquartile range]: 94.7 parts per billion (ppb) [70-129 ppb] vs 60.9 ppb [46-77 ppb], P < .001) and was associated with right atrial pressure (ρ = 0.57, P < .001), mean pulmonary artery pressure (ρ = 0.43, P = .015), cardiac index by thermodilution (ρ = −0.39, P = .03), pulmonary vascular resistance (ρ = 0.40, P = .04), mixed venous oxygen (ρ = −0.59, P < .001), and right ventricular dilation (ρ = 0.42, P = .03). Conclusions: Breathprint is different between patients with PAH and healthy control subjects. Several specific compounds, including ammonia, were elevated in the breath of patients with PAH. Exhaled ammonia levels correlated with severity of disease. PMID:24091389

  14. Houses need to breathe--right?

    SciTech Connect

    Sherman, Max H.

    2004-10-01

    Houses need to breathe, but we can no longer leave the important functions associated with ventilation to be met accidentally. A designed ventilation system must be considered as much a part of a home as its heating system. Windows are a key part of that system because they allow a quick increase in ventilation for unusual events, but neither they nor a leaky building shell can be counted on to provide minimum levels.

  15. Breath tests and irritable bowel syndrome

    PubMed Central

    Rana, Satya Vati; Malik, Aastha

    2014-01-01

    Breath tests are non-invasive tests and can detect H2 and CH4 gases which are produced by bacterial fermentation of unabsorbed intestinal carbohydrate and are excreted in the breath. These tests are used in the diagnosis of carbohydrate malabsorption, small intestinal bacterial overgrowth, and for measuring the orocecal transit time. Malabsorption of carbohydrates is a key trigger of irritable bowel syndrome (IBS)-type symptoms such as diarrhea and/or constipation, bloating, excess flatulence, headaches and lack of energy. Abdominal bloating is a common nonspecific symptom which can negatively impact quality of life. It may reflect dietary imbalance, such as excess fiber intake, or may be a manifestation of IBS. However, bloating may also represent small intestinal bacterial overgrowth. Patients with persistent symptoms of abdominal bloating and distension despite dietary interventions should be referred for H2 breath testing to determine the presence or absence of bacterial overgrowth. If bacterial overgrowth is identified, patients are typically treated with antibiotics. Evaluation of IBS generally includes testing of other disorders that cause similar symptoms. Carbohydrate malabsorption (lactose, fructose, sorbitol) can cause abdominal fullness, bloating, nausea, abdominal pain, flatulence, and diarrhea, which are similar to the symptoms of IBS. However, it is unclear if these digestive disorders contribute to or cause the symptoms of IBS. Research studies show that a proper diagnosis and effective dietary intervention significantly reduces the severity and frequency of gastrointestinal symptoms in IBS. Thus, diagnosis of malabsorption of these carbohydrates in IBS using a breath test is very important to guide the clinician in the proper treatment of IBS patients. PMID:24976698

  16. VLT observations of NGC 1097's ``dog-leg'' tidal stream. Dwarf spheroidals and tidal streams

    NASA Astrophysics Data System (ADS)

    Galianni, P.; Patat, F.; Higdon, J. L.; Mieske, S.; Kroupa, P.

    2010-10-01

    Aims: We investigate the structure and stellar population of two large stellar condensations (knots A & B) along one of the faint optical “jet-like” tidal streams associated with the spiral NGC 1097, with the goal of establishing their physical association with the galaxy and their origin. Methods: We use the VLT/FORS2 to get deep V-band imaging and low-resolution optical spectra of two knots along NGC 1097's northeast “dog-leg” tidal stream. With this data, we explore their morphology and stellar populations. Results: Spectra were obtained for eleven sources in the field surrounding the tidal stream. The great majority of them turned out to be background or foreground sources, but the redshift of knot A (and perhaps of knot B) is consistent with that of NGC 1097. Using the V-band image of the “dog-leg” tidal feature we find that the two knots match the photometric scaling relations of canonical dwarf spheroidal galaxies (dSph) very well. Spectral analysis shows that knot A is mainly composed of stars near G-type, with no signs of ongoing star formation. Comparing its spectrum with a library of high resolution spectra of galactic globular clusters (GCs), we find that the stellar population of this dSph-like object is most similar to intermediate to metal rich galactic GCs. We find moreover, that the tidal stream shows an “S” shaped inflection as well as a pronounced stellar overdensity at knot A's position. This suggests that knot A is being tidally stripped, and populating the stellar stream with its stars. Conclusions: We have discovered that two knots along NGC 1097's northeast tidal stream share most of their spectral and photometric properties with ordinary dwarf spheroidal galaxies (dSph). Moreover, we find strong indications that the “dog-leg” tidal stream arises from the tidal disruption of knot A. Since it has been demonstrated that tidally stripping dSph galaxies need to loose most of their dark matter before starting to loose stars

  17. Genetics and early disturbances of breathing control.

    PubMed

    Gaultier, Claude; Amiel, Jeanne; Dauger, Stéphane; Trang, Ha; Lyonnet, Stanislas; Gallego, Jorge; Simonneau, Michel

    2004-05-01

    Early disturbances in breathing control, including apneas of prematurity and apparently life-threatening events, account for some cases of sudden infant death syndrome and for a rare disorder called congenital central hypoventilation syndrome (CCHS). Data suggesting a genetic basis for CCHS have been obtained. Recently, we found heterozygous de novo mutations of the PHOX2B gene in 18 of 29 individuals with CCHS. Most mutations consisted of five to nine alanine expansions within a 20-residue polyalanine tract, probably resulting from nonhomologous recombination. Other mutations, generally inherited from one of the parents, in the coding regions of genes involved in the endothelin and RET signaling pathways and in the brain-derived-neurotrophic factor (BDNF) gene have been found in a few CCHS patients. Interestingly, all these genes are involved in the development of neural crest cells. Targeted disruption of these genes in mice has provided information on the pathophysiological mechanisms underlying CCHS. Despite the identification of these genes involved in breathing control, none of the genetically engineered mice developed to date replicate the full human CCHS respiratory phenotype. Recent insights into the genetic basis for CCHS may shed light on the genetics of other early disturbances in breathing control, such as apnea of prematurity and sudden infant death syndrome. PMID:14739359

  18. The immune response to resistive breathing.

    PubMed

    Vassilakopoulos, T; Roussos, C; Zakynthinos, S

    2004-12-01

    Resistive breathing is an "immune challenge" for the body, initiating an inflammatory response consisting of an elevation of plasma cytokines, and the recruitment and activation of lymphocyte subpopulations. These cytokines do not originate from monocytes, but are, instead, produced within the diaphragm, secondary to the increased muscle activation. Oxidative stress is a major stimulus for the cytokine induction, secondary to resistive breathing. The production of cytokines within the diaphragm may be mediating the diaphragm muscle fibre injury that occurs with strenuous contractions, or contributing towards the expected repair process. These cytokines may also compromise diaphragmatic contractility or contribute towards the development of muscle cachexia. They may also have systemic effects, mobilising glucose from the liver and free fatty acid from the adipose tissue to the strenuously working respiratory muscles. At the same time, they stimulate the hypothalamic-pituitary-adrenal axis, leading to production of adrenocorticotropin and beta-endorphins. The adrenocorticotropin response may represent an attempt of the organism to reduce the injury occurring in the respiratory muscles via the production of glucocorticoids and the induction of the acute phase-response proteins. The beta-endorphin response would decrease the activation of the respiratory muscles and change the pattern of breathing, which becomes more rapid and shallow, possibly in an attempt to reduce and/or prevent further injury to the respiratory muscles. PMID:15572550

  19. Ultrasensitive laser spectroscopy for breath analysis

    NASA Astrophysics Data System (ADS)

    Wojtas, J.; Bielecki, Z.; Stacewicz, T.; Mikołajczyk, J.; Nowakowski, M.

    2012-03-01

    At present there are many reasons for seeking new methods and technologies that aim to develop new and more perfect sensors for different chemical compounds. However, the main reasons are safety ensuring and health care. In the paper, recent advances in the human breath analysis by the use of different techniques are presented. We have selected non-invasive ones ensuring detection of pathogenic changes at a molecular level. The presence of certain molecules in the human breath is used as an indicator of a specific disease. Thus, the analysis of the human breath is very useful for health monitoring. We have shown some examples of diseases' biomarkers and various methods capable of detecting them. Described methods have been divided into non-optical and optical methods. The former ones are the following: gas chromatography, flame ionization detection, mass spectrometry, ion mobility spectrometry, proton transfer reaction mass spectrometry, selected ion flow tube mass spectrometry. In recent twenty years, the optical methods have become more popular, especially the laser techniques. They have a great potential for detection and monitoring of the components in the gas phase. These methods are characterized by high sensitivity and good selectivity. The spectroscopic sensors provide the opportunity to detect specific gases and to measure their concentration either in a sampling place or a remote one. Multipass spectroscopy, cavity ring-down spectroscopy, and photo-acoustic spectroscopy were characterised in the paper as well.

  20. [Model experiments on breathing under sand].

    PubMed

    Maxeiner, H; Haenel, F

    1985-01-01

    Remarkable autopsy findings in persons who had suffocated as a result of closure of the mouth and nose by sand (without the body being buried) induced us to investigate some aspects of this situation by means of a simple experiment. A barrel (diameter 36.7 cm) with a mouthpiece in the bottom was filled with sand to a depth of 15, 30, 60, or 90 cm. The subject tried to breathe as long as possible through the sand, while the amount of sand inspired was measured. Pressure and volume of the breath, as well as the O2 and CO2 content were also measured. A respiratory volume of up to 31 was possible, even when the depth was 90 cm. After about 1 min in all trials, the subject's shortness of breath forced us to stop the experiment. Measurement of O2 and CO2 concentrations proved that respiratory volume in and out of the sand shifts to atmospheric air without gas exchange, even when the sand depth is 15 cm. Sand aspiration depended on the moisture of the material: when the sand was dry, it was impossible to avoid aspiration. However, even a water content of only 5% prevented aspiration, although the sand seemed to be nearly dry.