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Sample records for rate modulation rate

  1. NREL module energy rating methodology

    SciTech Connect

    Whitaker, C.; Newmiller, J.; Kroposki, B.

    1995-11-01

    The goals of this project were to develop a tool for: evaluating one module in different climates; comparing different modules; provide a Q&D method for estimating periodic energy production; provide an achievable module rating; provide an incentive for manufacturers to optimize modules to non-STC conditions; and to have a consensus-based, NREL-sponsored activity. The approach taken was to simulate module energy for five reference days of various weather conditions. A performance model was developed.

  2. Unified Technical Concepts. Module 3: Rate.

    ERIC Educational Resources Information Center

    Technical Education Research Center, Waco, TX.

    This concept module on rate is one of thirteen modules that provide a flexible, laboratory-based physics instructional package designed to meet the specialized needs of students in two-year, postsecondary technical schools. Each of the thirteen concept modules discusses a single physics concept and how it is applied to each energy system. This…

  3. Unified Technical Concepts. Module 3: Rate.

    ERIC Educational Resources Information Center

    Technical Education Research Center, Waco, TX.

    This concept module on rate is one of thirteen modules that provide a flexible, laboratory-based physics instructional package designed to meet the specialized needs of students in two-year, postsecondary technical schools. Each of the thirteen concept modules discusses a single physics concept and how it is applied to each energy system. This…

  4. H2-blocker modulates heart rate variability.

    PubMed

    Ooie, T; Saikawa, T; Hara, M; Ono, H; Seike, M; Sakata, T

    1999-01-01

    The use of H2-blockers in the treatment of patients with peptic ulcer has become popular. However, this treatment has adverse cardiovascular effects. The aim of this study was to investigate proarrhythmic rhythm and autonomic nervous activity by analyzing heart rate variability in patients treated with omeprazole, ranitidine, and plaunotol. Nineteen patients (mean age 67.5 +/- 2.7 years) with active gastric ulcer were treated with omeprazole (20 mg/day) for 8 weeks, then ranitidine (300 mg/day) for the next 4 months, and finally plaunotol (240 mg/day). At each stage of the treatment, Holter electrocardiography was performed, and heart rate variability and arrhythmias analyzed. Heart rate variability yielded power in the low- (0.04-0.15 Hz) and high-frequency components (0.15-0.4 Hz). Although both ranitidine and omeprazole induced little change in cardiac rhythm, the high-frequency power was higher (10.3 +/- 0.8 vs 8.6 +/- 0.6 ms, P < 0.05) and the ratio of low-to-high frequency power was lower (1.41 +/-0.10 vs 1.59 +/- 0.09. P < 0.05) during ranitidine than during plaunotol treatment. Cosinor analysis of heart rate variability revealed a decreased amplitude of low-frequency power during omeprazole compared with during ranitidine and plaunotol treatment. Ranitidine modulated high-frequency power which may be related to the adverse cardiovascular effects of H2-blocker.

  5. Photovoltaic module energy rating methodology development

    SciTech Connect

    Kroposki, B.; Myers, D.; Emery, K.; Mrig, L.; Whitaker, C.; Newmiller, J.

    1996-05-01

    A consensus-based methodology to calculate the energy output of a PV module will be described in this paper. The methodology develops a simple measure of PV module performance that provides for a realistic estimate of how a module will perform in specific applications. The approach makes use of the weather data profiles that describe conditions throughout the US and emphasizes performance differences between various module types. An industry-representative Technical Review Committee has been assembled to provide feedback and guidance on the strawman and final approach used in developing the methodology.

  6. Photovoltaic module energy rating methodology development

    SciTech Connect

    Kroposki, B.; Myers, D.; Emery, K.; Mrig, L.; Whitaker, C.; Newmiller, J.

    1996-05-01

    A consensus-based methodology to calculate the energy output of a PV module will be described in this paper. The methodology develops a simple measure of PV module performance that provides for a realistic estimate of how a module will perform in specific applications. The approach makes use of the weather data profiles that describe conditions throughout the United States and emphasizes performance differences between various module types. An industry-representative Technical Review Committee has been assembled to provide feedback and guidance on the strawman and final approach used in developing the methodology.

  7. Invariance of firing rate and field potential dynamics to stimulus modulation rate in human auditory cortex.

    PubMed

    Mukamel, Roy; Nir, Yuval; Harel, Michal; Arieli, Amos; Malach, Rafael; Fried, Itzhak

    2011-08-01

    The effect of stimulus modulation rate on the underlying neural activity in human auditory cortex is not clear. Human studies (using both invasive and noninvasive techniques) have demonstrated that at the population level, auditory cortex follows stimulus envelope. Here we examined the effect of stimulus modulation rate by using a rare opportunity to record both spiking activity and local field potentials (LFP) in auditory cortex of patients during repeated presentations of an audio-visual movie clip presented at normal, double, and quadruple speeds. Mean firing rate during evoked activity remained the same across speeds and the temporal response profile of firing rate modulations at increased stimulus speeds was a linearly scaled version of the response during slower speeds. Additionally, stimulus induced power modulation of local field potentials in the high gamma band (64-128 Hz) exhibited similar temporal scaling as the neuronal firing rate modulations. Our data confirm and extend previous studies in humans and anesthetized animals, supporting a model in which both firing rate, and high-gamma LFP power modulations in auditory cortex follow the temporal envelope of the stimulus across different modulation rates.

  8. Sensitivity to Envelope Interaural Time Differences at High Modulation Rates

    PubMed Central

    Bleeck, Stefan; McAlpine, David

    2015-01-01

    Sensitivity to interaural time differences (ITDs) conveyed in the temporal fine structure of low-frequency tones and the modulated envelopes of high-frequency sounds are considered comparable, particularly for envelopes shaped to transmit similar fidelity of temporal information normally present for low-frequency sounds. Nevertheless, discrimination performance for envelope modulation rates above a few hundred Hertz is reported to be poor—to the point of discrimination thresholds being unattainable—compared with the much higher (>1,000 Hz) limit for low-frequency ITD sensitivity, suggesting the presence of a low-pass filter in the envelope domain. Further, performance for identical modulation rates appears to decline with increasing carrier frequency, supporting the view that the low-pass characteristics observed for envelope ITD processing is carrier-frequency dependent. Here, we assessed listeners’ sensitivity to ITDs conveyed in pure tones and in the modulated envelopes of high-frequency tones. ITD discrimination for the modulated high-frequency tones was measured as a function of both modulation rate and carrier frequency. Some well-trained listeners appear able to discriminate ITDs extremely well, even at modulation rates well beyond 500 Hz, for 4-kHz carriers. For one listener, thresholds were even obtained for a modulation rate of 800 Hz. The highest modulation rate for which thresholds could be obtained declined with increasing carrier frequency for all listeners. At 10 kHz, the highest modulation rate at which thresholds could be obtained was 600 Hz. The upper limit of sensitivity to ITDs conveyed in the envelope of high-frequency modulated sounds appears to be higher than previously considered. PMID:26721926

  9. Sensitivity to Envelope Interaural Time Differences at High Modulation Rates.

    PubMed

    Monaghan, Jessica J M; Bleeck, Stefan; McAlpine, David

    2015-12-30

    Sensitivity to interaural time differences (ITDs) conveyed in the temporal fine structure of low-frequency tones and the modulated envelopes of high-frequency sounds are considered comparable, particularly for envelopes shaped to transmit similar fidelity of temporal information normally present for low-frequency sounds. Nevertheless, discrimination performance for envelope modulation rates above a few hundred Hertz is reported to be poor-to the point of discrimination thresholds being unattainable-compared with the much higher (>1,000 Hz) limit for low-frequency ITD sensitivity, suggesting the presence of a low-pass filter in the envelope domain. Further, performance for identical modulation rates appears to decline with increasing carrier frequency, supporting the view that the low-pass characteristics observed for envelope ITD processing is carrier-frequency dependent. Here, we assessed listeners' sensitivity to ITDs conveyed in pure tones and in the modulated envelopes of high-frequency tones. ITD discrimination for the modulated high-frequency tones was measured as a function of both modulation rate and carrier frequency. Some well-trained listeners appear able to discriminate ITDs extremely well, even at modulation rates well beyond 500 Hz, for 4-kHz carriers. For one listener, thresholds were even obtained for a modulation rate of 800 Hz. The highest modulation rate for which thresholds could be obtained declined with increasing carrier frequency for all listeners. At 10 kHz, the highest modulation rate at which thresholds could be obtained was 600 Hz. The upper limit of sensitivity to ITDs conveyed in the envelope of high-frequency modulated sounds appears to be higher than previously considered. © The Author(s) 2015.

  10. Development of a photovoltaic module energy ratings methodology

    SciTech Connect

    Kroposki, B; Mrig, L; Whitaker, C; Newmiller, J

    1995-05-01

    The National Renewable Energy Laboratory has begun work on developing a consensus-based approach to rating photovoltaic modules. This new approach was intended to address the limitations of the defacto standard module power rating at standard test conditions. Using technical input from a number of sources, and under the guidance of an industry-based technical review committee, the approach described in this paper was developed. The Module Energy Rating (MER) consists of 10 estimates of how much energy a single typical module of a particular type will produce in one day, one for each of 5 different weather/location combinations and 2 load-types. This paper presents an overview of the procedures required to generate an MER for any particular module type.

  11. SOPHIA CPV module round robin: Power rating at CSOC

    NASA Astrophysics Data System (ADS)

    Siefer, Gerald; Steiner, Marc; Baudrit, Mathieu; Dominguez, César; Antón, Igancio; Nuñez, Ruben; Roca, Franco; Pugliatti, Paola Maria; Stefano, Agnese Di; Kenny, Robert; Morabito, Paolo

    2014-09-01

    In the frame of the European project SOPHIA a concentrator photovoltaic (CPV) module measurement round robin has been initiated. The round robin includes measurements of four CPV modules at seven different test laboratories located in Europe. IV curves of the modules are measured with different measurement equipment under various climatic conditions. The aim of this activity is to perform at each site a rating of the modules at concentrator standard operating conditions CSOC according to IEC 62670-1. The outcome of the round robin is intended for direct feedback to the current draft standard IEC 62670-3 "Concentrator Photovoltaic (CPV) Performance Testing - Performance Measurements and Power Rating". The paper discusses initial results from the first three partners that have already finished the measurements up to now.

  12. Photovoltaic module energy rating procedure. Final subcontract report

    SciTech Connect

    Whitaker, C.M.; Newmiller, J.D.

    1998-01-01

    This document describes testing and computation procedures used to generate a photovoltaic Module Energy Rating (MER). The MER consists of 10 estimates of the amount of energy a single module of a particular type (make and model) will produce in one day. Module energy values are calculated for each of five different sets of weather conditions (defined by location and date) and two load types. Because reproduction of these exact testing conditions in the field or laboratory is not feasible, limited testing and modeling procedures and assumptions are specified.

  13. Detection and rate discrimination of amplitude modulation in electrical hearing.

    PubMed

    Chatterjee, Monita; Oberzut, Cherish

    2011-09-01

    Three experiments were designed to examine temporal envelope processing by cochlear implant (CI) listeners. In experiment 1, the hypothesis that listeners' modulation sensitivity would in part determine their ability to discriminate between temporal modulation rates was examined. Temporal modulation transfer functions (TMTFs) obtained in an amplitude modulation detection (AMD) task were compared to threshold functions obtained in an amplitude modulation rate discrimination (AMRD) task. Statistically significant nonlinear correlations were observed between the two measures. In experiment 2, results of loudness-balancing showed small increases in the loudness of modulated over unmodulated stimuli beyond a modulation depth of 16%. Results of experiment 3 indicated small but statistically significant effects of level-roving on the overall gain of the TMTF, but no impact of level-roving on the average shape of the TMTF across subjects. This suggested that level-roving simply increased the task difficulty for most listeners, but did not indicate increased use of intensity cues under more challenging conditions. Data obtained with one subject, however, suggested that the most sensitive listeners may derive some benefit from intensity cues in these tasks. Overall, results indicated that intensity cues did not play an important role in temporal envelope processing by the average CI listener.

  14. Module energy rating candidate reference days: Criteria and selection process

    NASA Astrophysics Data System (ADS)

    Myers, Daryl R.

    1999-03-01

    Presently the performance of flat-plate photovoltaic (PV) modules is based upon module power, open circuit voltage, short-circuit current, or peak power voltage and current with respect to fixed environmental conditions such as Standard Reporting Conditions, (SRC) or nominal operating cell temperature. These reporting conditions represent ideal conditions under which PV module performance (e.g., between manufacturers or technologies) may be compared. They result in overly optimistic expectations of performance by PV industry customers. A recommended practice for PV module energy-rating methodologies to relate PV module performance to real world conditions is under development. The methodologies will provide system designers and PV customers with an energy rating representative of real world conditions. The rating methodology reports energy production under 5 selected types of days representative of possible operational environments. The development and application of qualitative and quantitative criteria for identifying and selecting these representative days from the 30-year U.S. National Solar Radiation Data Base is described.

  15. Symbol rate identification for auxiliary amplitude modulation optical signal

    NASA Astrophysics Data System (ADS)

    Wei, Junyu; Dong, Zhi; Huang, Zhiping; Zhang, Yimeng

    2016-09-01

    In this paper, we creatively propose and demonstrate a method for symbol rate identification (SRI) of auxiliary amplitude modulation (AAM) optical signal based on asynchronous delay-tap sampling (ADTS) and average magnitude difference function (AMDF). The method can accurately estimate symbol rate and has large transmission impairments tolerance. Furthermore, it can be realized in the digital signal processor (DSP) with low logical resources because of multiplication-free. In order to improve the accuracy of SRI, the peak to valley ratio (PTVR) of AMDF is introduced into our method for blind chromatic dispersion (CD) compensation. The results of the numerical simulations show that the overall maximum SRI error is smaller 0.079% for return-to-zero (RZ) on-off keying (OOK), RZ differential phase-shift keying (DPSK), RZ differential quadrature phase-shift keying (DQPSK) and RZ 16-ary quadrature amplitude modulation (QAM) with 50% duty cycles.

  16. Enhanced modulation rates via field modulation in spin torque nano-oscillators

    SciTech Connect

    Purbawati, A.; Garcia-Sanchez, F.; Buda-Prejbeanu, L. D.; Ebels, U.

    2016-03-21

    Spin Transfer Nano-Oscillators (STNOs) are promising candidates for telecommunications applications due to their frequency tuning capabilities via either a dc current or an applied field. This frequency tuning is of interest for Frequency Shift Keying concepts to be used in wireless communication schemes or in read head applications. For these technological applications, one important parameter is the characterization of the maximum achievable rate at which an STNO can respond to a modulating signal, such as current or field. Previous studies of in-plane magnetized STNOs on frequency modulation via an rf current revealed that the maximum achievable rate is limited by the amplitude relaxation rate Γ{sub p}, which gives the time scale over which amplitude fluctuations are damped out. This might be a limitation for applications. Here, we demonstrate via numerical simulation that application of an additional rf field is an alternative way for modulation of the in-plane magnetized STNO configuration, which has the advantage that frequency modulation is not limited by the amplitude relaxation rate, so that higher modulation rates above GHz are achievable. This occurs when the modulating rf field is oriented along the easy axis (longitudinal rf field). Tilting the direction of the modulating rf field in-plane and perpendicularly with respect to the easy axis (transverse rf field), the modulation is again limited by the amplitude relaxation rate similar to the response observed in current modulation.

  17. Effective transition rates for epitaxial growth using fast modulation

    NASA Astrophysics Data System (ADS)

    Gallivan, Martha A.; Goodwin, David G.; Murray, Richard M.

    2004-07-01

    Thin-film deposition is an industrially important process that is highly dependent on the processing conditions. Most films are grown under constant conditions, but a few studies show that modified properties may be obtained with periodic inputs. However, assessing the effects of modulation experimentally becomes impractical with increasing material complexity. Here we consider periodic conditions in which the period is short relative to the time scales of growth. We analyze a stochastic model of thin-film growth, computing effective transition rates associated with rapid periodic process parameters. Combinations of effective rates may exist that are not attainable under steady conditions, potentially enabling new film properties. An algorithm is presented to construct the periodic input for a desired set of effective transition rates. These ideas are demonstrated in three simple examples using kinetic Monte Carlo simulations of epitaxial growth.

  18. Contact rate modulates foraging efficiency in leaf cutting ants.

    PubMed

    Bouchebti, S; Ferrere, S; Vittori, K; Latil, G; Dussutour, A; Fourcassié, V

    2015-12-21

    Lane segregation is rarely observed in animals that move in bidirectional flows. Consequently, these animals generally experience a high rate of head-on collisions during their journeys. Although these collisions have a cost (each collision induces a delay resulting in a decrease of individual speed), they could also have a benefit by promoting information transfer between individuals. Here we explore the impact of head-on collisions in leaf-cutting ants moving on foraging trails by artificially decreasing the rate of head-on collisions between individuals. We show that head-on collisions do not influence the rate of recruitment in these ants but do influence foraging efficiency, i.e. the proportion of ants returning to the nest with a leaf fragment. Surprisingly, both unladen and laden ants returning to the nest participate in the modulation of foraging efficiency: foraging efficiency decreases when the rate of contacts with both nestbound laden or unladen ants decreases. These results suggest that outgoing ants are able to collect information from inbound ants even when these latter do not carry any leaf fragment and that this information can influence their foraging decisions when reaching the end of the trail.

  19. Contact rate modulates foraging efficiency in leaf cutting ants

    PubMed Central

    Bouchebti, S.; Ferrere, S.; Vittori, K.; Latil, G.; Dussutour, A.; Fourcassié, V.

    2015-01-01

    Lane segregation is rarely observed in animals that move in bidirectional flows. Consequently, these animals generally experience a high rate of head-on collisions during their journeys. Although these collisions have a cost (each collision induces a delay resulting in a decrease of individual speed), they could also have a benefit by promoting information transfer between individuals. Here we explore the impact of head-on collisions in leaf-cutting ants moving on foraging trails by artificially decreasing the rate of head-on collisions between individuals. We show that head-on collisions do not influence the rate of recruitment in these ants but do influence foraging efficiency, i.e. the proportion of ants returning to the nest with a leaf fragment. Surprisingly, both unladen and laden ants returning to the nest participate in the modulation of foraging efficiency: foraging efficiency decreases when the rate of contacts with both nestbound laden or unladen ants decreases. These results suggest that outgoing ants are able to collect information from inbound ants even when these latter do not carry any leaf fragment and that this information can influence their foraging decisions when reaching the end of the trail. PMID:26686557

  20. Respiratory modulation and baroreflex control of heart rate in space

    NASA Astrophysics Data System (ADS)

    Verheyden, Bart; Couckuyt, Kurt; Liu, Jiexin; Aubert, Andre

    During everyday life, gravity constantly stresses the human circulation by diminishing venous return in the upright position. This induces baroreflex-mediated cardiovascular adjustments that are aimed to prevent the blood pressure from falling. In weightlessness, gravitational pressure gradients do not arise in the circulation so that baroreflex function remains chronically unchallenged. This may contribute to the development of post spaceflight orthostatic intolerance. The purpose of this study was to evaluate respiratory modulation and baroreflex control of heart rate after a week of weightlessness in space. We tested the hypothesis that cardiovascular control in space will be similar to the baseline supine condition on Earth. We studied nine male cosmonauts during seven different space missions aboard the ISS (age 40 - 52 yrs, height 1.69 - 1.85 m, weight 67 - 90 kg). Data collection was performed between 30 and 45 days before launch in the standing and supine positions, and after 8 days in space. Cosmonauts were carefully trained to perform in-flight data collection by themselves. They were instructed to pace their breathing to a fixed rate of 12 breaths per minute (0.2 Hz) for a total duration of 3 minutes. The electrocardiogram and beat-by-beat finger arterial blood pressure were recorded at 1-kHz sample rate. Respiratory rate was evaluated using an abdominal pressure sensor. We used power spectral analysis to calculate respiratory sinus arrhythmia (RSA) as well as the low-frequency (0.04 - 0.15 Hz) powers of spontaneous oscillations in heart rate and systolic blood pressure. Baroreflex sensitivity (BRS) was estimated in the time domain using cross-correlation analysis. As expected, there was a rise in heart rate upon assuming the standing position before space- flight (59 ± 6 to 79 ± 11 beats per min; p ¡ 0.001). This was accompanied by an increase in mean arterial blood pressure (84 ± 6 to 93 ± 6 mmHg; p ¡ 0.001). Standing up further induced a marked

  1. Dominant Parasympathetic Modulation of Heart Rate and Heart Rate Variability in a Wild-Caught Seabird.

    PubMed

    Carravieri, Alice; Müller, Martina S; Yoda, Ken; Hayama, Shin-Ichi; Yamamoto, Maki

    2016-01-01

    Heart rate (HR) and heart rate variability (HRV) provide noninvasive measures of the relative activity of the parasympathetic nervous system (PNS), which promotes self-maintenance and restoration, and the sympathetic nervous system (SNS), which prepares an animal for danger. The PNS decreases HR, whereas the SNS increases HR. The PNS and SNS also contribute to oscillations in heartbeat intervals at different frequencies, producing HRV. HRV promotes resilience and adjustment capacity in the organism to intrinsic and extrinsic changes. Measuring HRV can reveal the condition and emotional state of animals, including aspects of their stress physiology. Until now, the functioning of the PNS and SNS and their relationship with other physiological systems have been studied almost exclusively in humans. In this study, we tested their influence on HR and HRV for the first time in a wild-caught seabird, the streaked shearwater (Calonectris leucomelas). We analyzed electrocardiograms collected from birds carrying externally attached HR loggers and that received injections that pharmacologically blocked the PNS, the SNS, or both, as well as those that received a saline (sham) injection or no injection (control). The PNS strongly dominated modulation of HR and also HRV across all frequencies, whereas the SNS contributed only slightly to low-frequency oscillations. The saline injection itself acted as a stressor, causing a dramatic drop in PNS activity in HRV and an increase in HR, though PNS activity continued to dominate even during acute stress. Dominant PNS activity is expected for long-lived species, which should employ physiological strategies that minimize somatic deterioration coming from stress.

  2. Zonal Flow Growth Rates: Modulational Instability vs Statistical Steady States.

    NASA Astrophysics Data System (ADS)

    Krommes, J. A.; Kolesnikov, R. A.

    2002-11-01

    The nonlinear growth rate of zonal flows has been the subject of various investigations. The calculations can be grouped into two major classes: those based on modulational instability of a fixed pump wave;(L. Chen et al., Phys. Plasmas 7), 3129 (2000); P. N. Guzdar et al., Phys. Rev. Lett. 87, 015001 (2001); C. N. Lashmore-Davies et al., Phys. Plasmas 8, 5121 (2001). and those employing statistical formalism to describe a self-consistent, energy-conserving steady state.(J. A. Krommes and C.--B. Kim, Phys. Rev. E 62), 8508 (2000), and references therein. The results from these two approaches do not necessarily agree either in their dependence on parameters like the plasma pressure β, on the threshold for instability, or even, in some cases, on the sign. The reasons for such disagreements are isolated, and it is shown to what extent the steady-state statistical approach can be reconciled with a generic modulational instability calculation. Generalizations of the statistical formalism to the multifield systems appropriate for finite β are described. Specific calculations based on model systems are used to illustrate the general arguments.

  3. Resting autonomic modulations and the heart rate response to exercise.

    PubMed

    Nunan, David; Jakovljevic, Djordje G; Donovan, Gay; Singleton, Lynette D; Sandercock, Gavin R H; Brodie, David A

    2010-08-01

    Identify the underlying role of resting heart rate variability (HRV) in the hearts response to graded exercise testing (GXT). Resting 5-min HRV and heart rate (HR) measurements were made in 33 volunteers (19 males, median age 34, range 25-63 years and 14 females median age 48, range 21-63 years). Measures of VO2 peak and HR obtained during a maximal GXT and heart rate recovery (HRR) post-GXT were assessed for associations with resting HRV. Differences and effect size (d) for measures of HRV were assessed between groups based on established risk cut-points for resting, exercise and recovery HR responses. Small associations were observed for the majority of resting HRV and GXT HR responses (best r value = -0.27, P > 0.05). Measures of HRV demonstrated moderate associations with HRR (best r value = 0.46, P < 0.05) and were able to predict a negative risk HRR. In contrast to other dependent variables, measures of HRV were consistently able to demonstrate significant and moderate to large (d = 0.9-2.0) differences between groups based on literature defined prognostic HR cut-points. Small associations with HR responses to exercise prevent their accurate prediction from resting HRV. Data support the use of vagally mediated resting HRV in predicting better HRR. Lower resting autonomic modulations underlined high risk resting and exercise HR responses. Resting short-term HRV measurements should be considered when assessing cardiac autonomic health from the HR response before, during and/or after exercise.

  4. High count rate gamma camera with independent modules

    NASA Astrophysics Data System (ADS)

    Massari, R.; Ucci, A.; Campisi, C.; Scopinaro, F.; Soluri, A.

    2015-11-01

    Advances in nuclear medical imaging are based on the improvements of the detector's performance. Generally the research is focussed on the spatial resolution improvement. However, another important parameter is the acquisition time that can significantly affect performance in some clinical investigation (e.g. first-pass cardiac studies). At present, there are several clinical imaging systems which are able to solve these diagnostic requirements, such as the D-SPECT Cardiac Imaging System (Spectrum Dynamics) or the Nucline Cardiodesk Medical Imaging System (Mediso). Actually, these solutions are organ-specific dedicated systems, while it would be preferable having general purpose planar detectors with high counting rate. Our group has recently introduced the use of scintillation matrices whose size is equal to the overall area of a position sensitive photomultiplier tube (PSPMT) in order to design a modular gamma camera. This study allowed optimising the overall pixel identification by improving and controlling the light collection efficiency of each PSPMT. Although we achieved a solution for the problems about the dead area at the junction of the PSPMTs when they are set side by side. In this paper, we propose a modular gamma camera design as the basis to build large area detectors. The modular detector design allows us to achieve better counting performance. In this approach, each module that is made of one or more PSPMTs, can actually acquire data independently and simultaneously, increasing the overall detection efficiency. To verify the improvement in count rate capability we have built two detectors with a field of view of 5 × 5cm2, by using four R8900-C12 PSPMTs (Hamamatsu Photonics K.K.). Each PSPMT was coupled to a dedicated discrete scintillation structure designed to obtain a good homogeneity, high imaging performance and high efficiency. One of the detectors was designed as a standard gamma camera, while the other was composed by four independent

  5. Gum chewing modulates heart rate variability under noise stress.

    PubMed

    Ekuni, Daisuke; Tomofuji, Takaaki; Takeuchi, Noriko; Morita, Manabu

    2012-12-01

    Gum chewing may relieve stress, although this hypothesis has not been proven. Heart-rate variability (HRV) is commonly used to measure stress levels. However, it is not known if gum chewing modulates HRV under acute stress. The aim of this study was to investigate the effects of gum chewing on HRV under acute stress. A cross-over study involving 47 non-smoking healthy subjects, aged 22-27 years, was carried out. The subjects received a stress procedure with gum chewing (GS group) and without gum chewing (S group). Additionally, the other 20 subjects were allocated to the gum chewing without stress group (G group). The GS and S groups were exposed to noise for 5 min (75 dBA) as stress. Before and after stress exposure/gum chewing, participants completed the state portion of the State-Trait Anxiety Inventory (STAI-s) and a single Stress Visual Analogue Scale (VAS) measurement. HRV measurement was performed before and during stress/gum chewing for 5 min. After the stress procedure, VAS score significantly increased in the GS and S groups. During the stress procedure, the GS group showed a significantly lower level of high frequency (HF) and higher levels of low frequency (LF) and LF/HF than the S group. However, there were no significant differences in the scores of the state portion of the State-Trait Anxiety Inventory (STAI-s) and VAS between the two stress groups. These findings suggest that gum chewing modulates HRV, but may not relieve acute stress caused by noise.

  6. Radiation Hardened, Modulator ASIC for High Data Rate Communications

    NASA Technical Reports Server (NTRS)

    McCallister, Ron; Putnam, Robert; Andro, Monty; Fujikawa, Gene

    2000-01-01

    Satellite-based telecommunication services are challenged by the need to generate down-link power levels adequate to support high quality (BER approx. equals 10(exp 12)) links required for modem broadband data services. Bandwidth-efficient Nyquist signaling, using low values of excess bandwidth (alpha), can exhibit large peak-to-average-power ratio (PAPR) values. High PAPR values necessitate high-power amplifier (HPA) backoff greater than the PAPR, resulting in unacceptably low HPA efficiency. Given the high cost of on-board prime power, this inefficiency represents both an economical burden, and a constraint on the rates and quality of data services supportable from satellite platforms. Constant-envelope signals offer improved power-efficiency, but only by imposing a severe bandwidth-efficiency penalty. This paper describes a radiation- hardened modulator which can improve satellite-based broadband data services by combining the bandwidth-efficiency of low-alpha Nyquist signals with high power-efficiency (negligible HPA backoff).

  7. Sleep-Dependent Modulation of Metabolic Rate in Drosophila.

    PubMed

    Stahl, Bethany A; Slocumb, Melissa E; Chaitin, Hersh; DiAngelo, Justin R; Keene, Alex C

    2017-08-01

    Dysregulation of sleep is associated with metabolic diseases, and metabolic rate (MR) is acutely regulated by sleep-wake behavior. In humans and rodent models, sleep loss is associated with obesity, reduced metabolic rate, and negative energy balance, yet little is known about the neural mechanisms governing interactions between sleep and metabolism. We have developed a system to simultaneously measure sleep and MR in individual Drosophila, allowing for interrogation of neural systems governing interactions between sleep and metabolic rate. Like mammals, MR in flies is reduced during sleep and increased during sleep deprivation suggesting sleep-dependent regulation of MR is conserved across phyla. The reduction of MR during sleep is not simply a consequence of inactivity because MR is reduced ~30 minutes following the onset of sleep, raising the possibility that CO2 production provides a metric to distinguish different sleep states in the fruit fly. To examine the relationship between sleep and metabolism, we determined basal and sleep-dependent changes in MR is reduced in starved flies, suggesting that starvation inhibits normal sleep-associated effects on metabolic rate. Further, translin mutant flies that fail to suppress sleep during starvation demonstrate a lower basal metabolic rate, but this rate was further reduced in response to starvation, revealing that regulation of starvation-induced changes in MR and sleep duration are genetically distinct. Therefore, this system provides the unique ability to simultaneously measure sleep and oxidative metabolism, providing novel insight into the physiological changes associated with sleep and wakefulness in the fruit fly.

  8. Rating PV Power and Energy: Cell, Module, and System Measurements

    SciTech Connect

    Emery, Keith

    2016-06-02

    A summary of key points related to research-level measurements of current vs. voltage measurement theory including basic PV operation, equivalent circuit, and concept of spectral error; PV power performance including PV irradiance sensors, simulators and commercial and generic I-V systems; PV measurement artifacts, intercomparisons, and alternative rating methods.

  9. Dopamine Modulates Metabolic Rate and Temperature Sensitivity in Drosophila melanogaster

    PubMed Central

    Ueno, Taro; Tomita, Jun; Kume, Shoen; Kume, Kazuhiko

    2012-01-01

    Homeothermal animals, such as mammals, maintain their body temperature by heat generation and heat dissipation, while poikilothermal animals, such as insects, accomplish it by relocating to an environment of their favored temperature. Catecholamines are known to regulate thermogenesis and metabolic rate in mammals, but their roles in other animals are poorly understood. The fruit fly, Drosophila melanogaster, has been used as a model system for the genetic studies of temperature preference behavior. Here, we demonstrate that metabolic rate and temperature sensitivity of some temperature sensitive behaviors are regulated by dopamine in Drosophila. Temperature-sensitive molecules like dTrpA1 and shits induce temperature-dependent behavioral changes, and the temperature at which the changes are induced were lowered in the dopamine transporter-defective mutant, fumin. The mutant also displays a preference for lower temperatures. This thermophobic phenotype was rescued by the genetic recovery of the dopamine transporter in dopamine neurons. Flies fed with a dopamine biosynthesis inhibitor (3-iodo-L-tyrosine), which diminishes dopamine signaling, exhibited preference for a higher temperature. Furthermore, we found that the metabolic rate is up-regulated in the fumin mutant. Taken together, dopamine has functions in the temperature sensitivity of behavioral changes and metabolic rate regulation in Drosophila, as well as its previously reported functions in arousal/sleep regulation. PMID:22347491

  10. Dopamine modulates metabolic rate and temperature sensitivity in Drosophila melanogaster.

    PubMed

    Ueno, Taro; Tomita, Jun; Kume, Shoen; Kume, Kazuhiko

    2012-01-01

    Homeothermal animals, such as mammals, maintain their body temperature by heat generation and heat dissipation, while poikilothermal animals, such as insects, accomplish it by relocating to an environment of their favored temperature. Catecholamines are known to regulate thermogenesis and metabolic rate in mammals, but their roles in other animals are poorly understood. The fruit fly, Drosophila melanogaster, has been used as a model system for the genetic studies of temperature preference behavior. Here, we demonstrate that metabolic rate and temperature sensitivity of some temperature sensitive behaviors are regulated by dopamine in Drosophila. Temperature-sensitive molecules like dTrpA1 and shi(ts) induce temperature-dependent behavioral changes, and the temperature at which the changes are induced were lowered in the dopamine transporter-defective mutant, fumin. The mutant also displays a preference for lower temperatures. This thermophobic phenotype was rescued by the genetic recovery of the dopamine transporter in dopamine neurons. Flies fed with a dopamine biosynthesis inhibitor (3-iodo-L-tyrosine), which diminishes dopamine signaling, exhibited preference for a higher temperature. Furthermore, we found that the metabolic rate is up-regulated in the fumin mutant. Taken together, dopamine has functions in the temperature sensitivity of behavioral changes and metabolic rate regulation in Drosophila, as well as its previously reported functions in arousal/sleep regulation.

  11. Membrane potential modulates photocycling rates of bacterial rhodopsins.

    PubMed

    Manor, D; Hasselbacher, C A; Spudich, J L

    1988-08-09

    Effects of membrane potential on photochemical reactions of three retinal-containing chromoproteins in Halobacterium halobium, sensory rhodopsin I (sR-I), bacteriorhodopsin, and halorhodopsin, are described. Each of the three exhibits a decreased rate of thermal decay of its principal intermediate when photoactivated in an artificially energized compared to a deenergized membrane. The similar response of the three pigments suggests a voltage-dependent conformational change common to their respective photocycles. Spectral and kinetic properties of the sR-I photochemical reaction cycle were measured in phototactic H. halobium cells, and differences from in vitro photocycle kinetics were attributable to the electrical membrane potential present in vivo. In vivo sR-I photocycling rates were reproduced in envelope vesicle preparations in the presence of a valinomycin-induced potassium diffusion potential.

  12. Modulation recognition for variable-rate QAM schemes

    NASA Astrophysics Data System (ADS)

    Lin, Yu-Chuan; Kuo, C.-C. Jay

    1995-12-01

    For some applications such as mobile communication or transmission of multimedia data, it is desirable to use modems with variable constellation schemes to adapt to the fast changing channel to accommodate a wide range of data transmission rates, bit error rates and data types. In this research we are interested in designing receivers which can identify the QAM constellation schemes from the received signal with an unknown reference phase. The problem is modeled as an M-ary hypothesis test with each hypothesis corresponding to one of the M possible constellation schemes. We show the performance of BPSK, QPSK, 8-PSK, 16-PSK, V.29-7200 bps, V.29-9600 bps, 16-QAM, 32-QAM, 64-QAM, 128-QAM, and 256-QAM classifiers in numerical experiments.

  13. Impact of shear rate modulation on vascular function in humans

    PubMed Central

    Tinken, Toni M.; Thijssen, Dick H.J.; Hopkins, Nicola; Black, Mark A.; Dawson, Ellen A.; Minson, Christopher T.; Newcomer, Sean C.; Laughlin, M. Harold; Cable, N. Timothy; Green, Daniel J.

    2010-01-01

    Shear stress is an important stimulus to arterial adaptation in response to exercise and training in humans. We recently observed significant reverse arterial flow and shear during exercise and different antegrade/retrograde patterns of shear and flow in response to different types of exercise. The purpose of this study was to simultaneously examine flow mediated dilation (FMD), a largely nitric oxide mediated vasodilator response, in both brachial arteries of healthy young men before and after 30-minute interventions consisting of bilateral forearm heating, recumbent leg cycling and bilateral handgrip exercise. During each intervention, a cuff inflated to 60mmHg was placed on one arm to unilaterally manipulate the shear rate stimulus. In the non-cuffed arm, antegrade flow and shear increased similarly in response to each intervention (ANOVA; P<0.001, no interaction between interventions; P=0.71). Baseline FMD (4.6, 6.9 and 6.7%) increased similarly in response to heating, handgrip and cycling (8.1, 10.4 and 8.9%, ANOVA; P<0.001, no interaction; 0.89). In contrast, cuffed arm antegrade shear rate was lower than in the non-cuffed arm for all conditions (P<0.05) and the increase in FMD was abolished in this arm (4.7, 6.7 and 6.1%) (2-way ANOVA: all conditions interacted P<0.05). These results suggest that differences in the magnitude of antegrade shear rate transduce differences in endothelial vasodilator function in humans, a finding which may have relevance for the impact of different exercise interventions on vascular adaptation in humans. PMID:19546374

  14. Encoding of frequency-modulation (FM) rates in human auditory cortex

    PubMed Central

    Okamoto, Hidehiko; Kakigi, Ryusuke

    2015-01-01

    Frequency-modulated sounds play an important role in our daily social life. However, it currently remains unclear whether frequency modulation rates affect neural activity in the human auditory cortex. In the present study, using magnetoencephalography, we investigated the auditory evoked N1m and sustained field responses elicited by temporally repeated and superimposed frequency-modulated sweeps that were matched in the spectral domain, but differed in frequency modulation rates (1, 4, 16, and 64 octaves per sec). The results obtained demonstrated that the higher rate frequency-modulated sweeps elicited the smaller N1m and the larger sustained field responses. Frequency modulation rate had a significant impact on the human brain responses, thereby providing a key for disentangling a series of natural frequency-modulated sounds such as speech and music. PMID:26656920

  15. Encoding of frequency-modulation (FM) rates in human auditory cortex.

    PubMed

    Okamoto, Hidehiko; Kakigi, Ryusuke

    2015-12-14

    Frequency-modulated sounds play an important role in our daily social life. However, it currently remains unclear whether frequency modulation rates affect neural activity in the human auditory cortex. In the present study, using magnetoencephalography, we investigated the auditory evoked N1m and sustained field responses elicited by temporally repeated and superimposed frequency-modulated sweeps that were matched in the spectral domain, but differed in frequency modulation rates (1, 4, 16, and 64 octaves per sec). The results obtained demonstrated that the higher rate frequency-modulated sweeps elicited the smaller N1m and the larger sustained field responses. Frequency modulation rate had a significant impact on the human brain responses, thereby providing a key for disentangling a series of natural frequency-modulated sounds such as speech and music.

  16. Detection of frequency modulation by hearing-impaired listeners: Effects of carrier frequency, modulation rate, and added amplitude modulation

    NASA Astrophysics Data System (ADS)

    Moore, Brian C. J.; Skrodzka, Ewa

    2002-01-01

    It has been proposed that the detection of frequency modulation (FM) of sinusoidal carriers can be mediated by two mechanisms: a place mechanism based on FM-induced amplitude modulation (AM) in the excitation pattern, and a temporal mechanism based on phase-locking in the auditory nerve. The temporal mechanism appears to be ``sluggish'' and does not play a role for FM rates above about 10 Hz. It also does not play a role for high carrier frequencies (above about 5 kHz). This experiment examined FM detection in three young subjects with normal hearing and four elderly subjects with cochlear hearing loss. Carrier frequencies were 0.25, 0.5, 1, 2, 4, and 6 kHz and modulation rates were 2, 5, 10, and 20 Hz. FM detection thresholds were measured both in the absence of AM, and with AM of a fixed depth (m=0.33) added in both intervals of a forced-choice trial. The added AM was intended to disrupt cues based on FM-induced AM in the excitation pattern. Generally, the hearing-impaired subjects performed markedly more poorly than the normal-hearing subjects. For the normal-hearing subjects, the disruptive effect of the AM tended to increase with increasing modulation rate, for carrier frequencies below 6 kHz, as found previously by Moore and Sek [J. Acoust. Soc. Am. 100, 2320-2331 (1996)]. For the hearing-impaired subjects, the disruptive effective of the AM was generally larger than for the normal-hearing subjects, and the magnitude of the disruption did not consistently increase with increasing modulation rate. The results suggest that cochlear hearing impairment adversely affects both temporal and excitation pattern mechanisms of FM detection.

  17. Ionospheric Modulation of Venus Express Lightning Detection Rates

    NASA Astrophysics Data System (ADS)

    Hart, Richard A.; Russell, Christopher T.; Zhang, Tielong

    2015-11-01

    Venus Express completed its nearly 9 year campaign at Earth’s sister planet in late 2014. During this period the onboard fluxgate magnetometer collected data up to 64 Hz in frequency while near periapsis. This is the expected frequency range for lightning-generated whistler-mode waves at Venus, between the local electron and ion gyrofrequencies. These waves are right-hand circularly polarized and are guided by the local magnetic field. When the Venusian ionopause is low enough in altitude to reside in the collisional region, the interplanetary magnetic field can get carried down with the ions and magnetize the lower ionosphere. As the field travels towards the terminator it gains a radial component, enabling whistlers to reach higher altitudes and be detected by the spacecraft. The mission covered almost an entire solar cycle and frequently observed a magnetized ionosphere during the solar minimum phase when the ionosphere was weak due to reduced incident EUV. Detection was most common at 250 km altitude where the waves travel more slowly due to reduced ionospheric density. In response they increase in amplitude in order to conserve magnetic energy flux. Here, we examine the changes in the ionospheric properties associated with the evolution of the solar cycle and the rate of detection of these lightning-generated signals.

  18. Social--Population Growth Rate Learning Module. Development Education Program.

    ERIC Educational Resources Information Center

    World Bank, Washington, DC.

    This learning module has two main goals: (1) to increase students' knowledge and understanding of the often complex relationship between sustainable development and the social, economic, and environmental conditions in a country; and (2) to strengthen students' abilities to perform statistical calculations, make and interpret maps, charts, and…

  19. Modulation of sympathetic activity and heart rate variability by ivabradine.

    PubMed

    Dias da Silva, Valdo Jose; Tobaldini, Eleonora; Rocchetti, Marcella; Wu, Maddalena A; Malfatto, Gabriella; Montano, Nicola; Zaza, Antonio

    2015-10-01

    Bradycardic agents are currently used in the treatment of angina and heart failure; direct information on their effects on cardiac sympathetic nerve activity (SNA) may be relevant to their chronic use. The present study evaluates the effect of pacemaker inhibition on SNA; direct nerve recordings and indirect autonomic indexes are compared. Experiments were performed in 18 anaesthetized rats. SNA (direct nerve recording) and heart rate variability (HRV) indexes were evaluated in parallel. All parameters were recorded 10 min before to 60 min after administration of the If blocker ivabradine (IVA; 2 mg/kg, i.v.; n = 8) or vehicle (VEH; n = 5). IVA-induced RR interval (RR) prolongation (at 60 min +15.0 ± 7.1%, P < 0.01) was associated with decreased diastolic arterial pressure (DAP; -17.3 ± 8.4%, P < 0.05) and increased SNA (+51.1 ± 12.3%, P < 0.05). These effects were accompanied by increased RR variance (RRσ(2)), which showed strong positive correlation with RR. Frequency-domain HRV indexes (in normalized units) were unchanged by IVA. After baroreceptor reflexes had been eliminated by sino-aortic denervation (n = 5), similar IVA-induced RR prolongation (at 60 min +14.3 ± 5.9%, NS vs. intact) was associated with a larger DAP reduction (-30.9 ± 4.1%, P < 0.05 vs. intact), but failed to affect SNA. (i) IVA-induced bradycardia was associated with increased SNA, resulting from baroreceptor unloading; if this applied to chronic IVA use in humans, it would be of relevance for therapeutic use of the drug. (ii) Whenever mean HR is concomitantly changed, time-domain HRV indexes should not be unequivocally interpreted in terms of autonomic balance. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  20. Combinatorial FSK modulation for power-efficient high-rate communications

    NASA Technical Reports Server (NTRS)

    Wagner, Paul K.; Budinger, James M.; Vanderaar, Mark J.

    1991-01-01

    Deep-space and satellite communications systems must be capable of conveying high-rate data accurately with low transmitter power, often through dispersive channels. A class of noncoherent Combinatorial Frequency Shift Keying (CFSK) modulation schemes is investigated which address these needs. The bit error rate performance of this class of modulation formats is analyzed and compared to the more traditional modulation types. Candidate modulator, demodulator, and digital signal processing (DSP) hardware structures are examined in detail. System-level issues are also discussed.

  1. A long lifetime, low error rate RRAM design with self-repair module

    NASA Astrophysics Data System (ADS)

    Zhiqiang, You; Fei, Hu; Liming, Huang; Peng, Liu; Jishun, Kuang; Shiying, Li

    2016-11-01

    Resistive random access memory (RRAM) is one of the promising candidates for future universal memory. However, it suffers from serious error rate and endurance problems. Therefore, exploring a technical solution is greatly demanded to enhance endurance and reduce error rate. In this paper, we propose a reliable RRAM architecture that includes two reliability modules: error correction code (ECC) and self-repair modules. The ECC module is used to detect errors and decrease error rate. The self-repair module, which is proposed for the first time for RRAM, can get the information of error bits and repair wear-out cells by a repair voltage. Simulation results show that the proposed architecture can achieve lowest error rate and longest lifetime compared to previous reliable designs. Project supported by the New Century Excellent Talents in University (No. NCET-12-0165) and the National Natural Science Foundation of China (Nos. 61472123, 61272396).

  2. Modulation of heart rate by acute or chronic aerobic exercise. Potential effects on blood pressure control.

    PubMed

    Perez-Quilis, Carme; Kingsley, J Derek; Malkani, Kabir; Cervellin, Gianfranco; Lippi, Giuseppe; Sanchis-Gomar, Fabian

    2017-07-10

    It was initially assumed that heart rate and arterial blood pressure were modulated by normal respiration and muscle contraction. The arterial baroreflex, an inverse relationship between blood pressure and heart rate, was later reported. Nonetheless, it was then assumed that those responses involved vagal modulation. We summarize available evidence on the modulation of heart rate by acute or chronic aerobic exercise as well as its potential implications on BP control. Numerous studies have tried to clarify whether aerobic exercise modifies neurally-mediated vasoconstriction, but they report contradictory results. In view of these incongruities, the aim of this narrative review is to summarize available evidence on the modulation of heart rate by acute or chronic aerobic exercise as well as its potential implications on blood pressure control. We mainly focus on the effects of aerobic exercise in both heart rate and blood pressure. Heart rate and heart rate variability have been indistinctly considered similar metrics, but they have completely different meanings when properly used. Both are risk markers in cardiac disease, whereas heart rate variability is also an index of sympathovagal modulation of heart rate. On the other hand, heart rate recovery has been also used as an index for mirroring both cardiovascular fitness and autonomic function, and can be used as a measure of vagal reactivation. Importantly, it is now well-known that a reduced rate of heart rate recovery represents a powerful predictor of overall mortality. In this review, due to its complexity, we have included studies in which any of these three parameters have been analyzed. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Use of Pyranometers to Estimate PV Module Degradation Rates in the Field

    SciTech Connect

    Vignola, Frank; Peterson, Josh; Kessler, Rich; Mavromatakis, Fotis; Dooraghi, Mike; Sengupta, Manajit

    2016-06-05

    This poster provides an overview of a methodology that uses relative measurements to estimate the degradation rates of PV modules in the field. The importance of calibration and cleaning is illustrated. The number of years of field measurements needed to measure degradation rates with data from the field is cut in half using relative comparisons.

  4. Use of Pyranometers to Estimate PV Module Degradation Rates in the Field

    SciTech Connect

    Vignola, Frank; Peterson, Josh; Kessler, Rich; Mavromatakis, Fotis; Dooraghi, Mike; Sengupta, Manajit

    2016-11-21

    Methodology is described that uses relative measurements to estimate the degradation rates of PV modules in the field. The importance of calibration and cleaning is discussed. The number of years of field measurements needed to measure degradation rates with data from the field is cut in half using relative comparisons.

  5. Use of Pyranometers to Estimate PV Module Degradation Rates in the Field: Preprint

    SciTech Connect

    Vignola, Frank; Peterson, Josh; Kessler, Rich; Mavromatakis, Fotis; Dooraghi, Mike; Sengupta, Manajit

    2016-08-01

    This paper describes a methodology that uses relative measurements to estimate the degradation rates of PV modules in the field. The importance of calibration and cleaning is illustrated. The number of years of field measurements needed to measure degradation rates with data from the field is cut in half using relative comparisons.

  6. The Influence of Motor Impairment on Autonomic Heart Rate Modulation among Children with Cerebral Palsy

    ERIC Educational Resources Information Center

    Zamuner, Antonio Roberto; Cunha, Andrea Baraldi; da Silva, Ester; Negri, Ana Paola; Tudella, Eloisa; Moreno, Marlene Aparecida

    2011-01-01

    The study of heart rate variability is an important tool for a noninvasive evaluation of the neurocardiac integrity. The present study aims to evaluate the autonomic heart rate modulation in supine and standing positions in 12 children diagnosed with cerebral palsy and 16 children with typical motor development (control group), as well as to…

  7. The Influence of Motor Impairment on Autonomic Heart Rate Modulation among Children with Cerebral Palsy

    ERIC Educational Resources Information Center

    Zamuner, Antonio Roberto; Cunha, Andrea Baraldi; da Silva, Ester; Negri, Ana Paola; Tudella, Eloisa; Moreno, Marlene Aparecida

    2011-01-01

    The study of heart rate variability is an important tool for a noninvasive evaluation of the neurocardiac integrity. The present study aims to evaluate the autonomic heart rate modulation in supine and standing positions in 12 children diagnosed with cerebral palsy and 16 children with typical motor development (control group), as well as to…

  8. A Self Rating Scale as a Pre and Post Assessment Tool for Use with Instructional Modules.

    ERIC Educational Resources Information Center

    Gotts, Sandra Harris

    This article describes a self rating pre- and post-assessment instrument that has been developed at the Central Michigan University (CMU). Nine instructional modules have been developed and are being used in science methods courses at CMU. Each module focuses on an identified area of competency for elementary science teachers and contains a…

  9. A Self Rating Scale as a Pre and Post Assessment Tool for Use with Instructional Modules.

    ERIC Educational Resources Information Center

    Gotts, Sandra Harris

    This article describes a self rating pre- and post-assessment instrument that has been developed at the Central Michigan University (CMU). Nine instructional modules have been developed and are being used in science methods courses at CMU. Each module focuses on an identified area of competency for elementary science teachers and contains a…

  10. Modeling of Diffusion Based Correlations Between Heart Rate Modulations and Respiration Pattern

    DTIC Science & Technology

    2001-10-25

    1 of 4 MODELING OF DIFFUSION BASED CORRELATIONS BETWEEN HEART RATE MODULATIONS AND RESPIRATION PATTERN R.Langer,(1) Y.Smorzik,(2) S.Akselrod,(1...generations of the bronchial tree. The second stage describes the oxygen diffusion process from the pulmonary gas in the alveoli into the pulmonary...patterns (FRC, TV, rate). Keywords – Modeling, Diffusion , Heart Rate fluctuations I. INTRODUCTION Under a whole-body management perception, the

  11. International PV QA Task Force's Proposed Comparative Rating System for PV Modules: Preprint

    SciTech Connect

    Wohlgemuth, J.; Kurtz, S.

    2014-10-01

    The International PV Quality Assurance Task Force is developing a rating system that provides comparative information about the relative durability of PV modules. Development of accelerated stress tests that can provide such comparative information is seen as a major step toward being able to predict PV module service life. This paper will provide details of the ongoing effort to determine the format of such an overall module rating system. The latest proposal is based on using three distinct climate zones as defined in IEC 60721-2-1 for two different mounting systems. Specific stresses beyond those used in the qualification tests are being developed for each of the selected climate zones.

  12. 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.

  13. 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.

  14. Determining Muon Detection Efficiency Rates of Limited Streamer Tube Modules using Cosmic Ray Detector

    SciTech Connect

    Pan, M.

    2004-09-03

    In the Babar detector at the Stanford Linear Accelerator Center, the existing muon detector system in the Instrumented Flux Return gaps is currently being upgraded. Limited Streamer Tubes (LST) have been successful in other projects in the past, and are thus reliable and sensible detectors to use. The tubes have been assembled into modules to strengthen the mechanical structure [2]. Before installation, numerous tests must be performed on the LST modules to ensure that they are in good condition. One important check is to determine the muon detection efficiency rates of the modules. In this study, a cosmic ray detector was built to measure the efficiency rates of the LST modules. Five modules themselves were used as muon triggers. Two z strip planes were also constructed as part of the setup. Singles rate measurements were done on the five modules to ensure that high voltage could be safely applied to the LST. Particle count vs. voltage graphs were generated, and most of the graphs plateau normally. Wire signals from the LST modules as well as induced signals from the strip planes were used to determine the x-y-z coordinates of the muon hits in a stack of modules. Knowing the geometry of the stack, a plot of the potential muon path was generated. Preliminary results on muon detection efficiency rates of the modules in one stack are presented here. Efficiencies of the modules were determined to be between 80% and 90%, but there were large statistical errors (7%) due to the limited time available for cosmic data runs. More data samples will be taken soon; they will hopefully provide more precise measurements, with 1-2% errors for most modules before installation. Future work includes systematic studies of muon detection efficiency as a function of the operating voltage and threshold voltage settings.

  15. Modulation of Tenoxicam release from hydrophilic matrix: modulator membrane versus rate-controlling membrane.

    PubMed

    El-Nabarawi, Mohamed Ahmed

    2005-09-01

    This paper describes the preparation of two layered device comprising of tenoxicam containing layer and a drug free membrane layer based on Geomatrix Technology. Our device based on bilaminated films which produced by a casting/solvent evaporation technique. The drug-hydroxypropyl methylcellulose (HPMC) layer was covered by drug free membrane layer composed of a mixture of different ratios of HPMC and ethyl cellulose (EC). The prepared devices were evaluated for thickness, weight, drug content uniformity, water absorption capacity and in-vitro drug release. The films were also evaluated for appearance, smoothness and transparency. The influence of drug free membrane layer composition and thickness on the drug release pattern was studied on 12 devices (D1 to D12). The results indicate that, the release of drug from HPMC matrixes without the drug free membrane layer was fast and follows diffusion controlled mechanism. The release of drug from the devices D1, D4, D9 and D12 follow the same mechanism, while the release of drug from other devices become linear with time (zero order) and extended for long time especially when thickness and the ratio of EC was increased in the drug free membrane layer. From this study it is concluded that, changing the geometry of drug layer by addition of drug free membrane layer and changing its composition and thickness plays an important role in determining whether the drug free membrane layer is rate-controlling or modulator membrane. Hence it can facilitate the development of different pharmaceutical products with different release pattern.

  16. Surface supersaturation in flow-rate modulation epitaxy of GaN

    NASA Astrophysics Data System (ADS)

    Akasaka, Tetsuya; Lin, Chia-Hung; Yamamoto, Hideki; Kumakura, Kazuhide

    2017-06-01

    Hillocks on N-face GaN (000 1 bar) films are effectively eliminated by group-III-source flow-rate modulation epitaxy (FME), wherein the flow-rate of group-III sources are sequentially modulated under a constant supply of NH3. A hillock-free smooth surface obtained by group-III-source FME is attributed to the enhancement of step-flow growth. We found that a hillock originates from a micropipe and grows by spiral growth around the micropipe. The spiral growth rate rapidly decreases with decreasing the degree of surface supersaturation σ, while the step-flow growth rate decreases linearly. For group-III-source FME, wherein σ is lower than conventional continuous growth, the spiral growth rate could be lower than the step-flow growth one so that the formation of hillocks is suppressed.

  17. The effects of oxytocin and atosiban on the modulation of heart rate in pregnant women.

    PubMed

    Weissman, Amir; Tobia, Rana Swed; Burke, Yechiel Z; Maxymovski, Olga; Drugan, Arie

    2017-02-01

    To evaluate autonomic modulation of heart rate in pregnant women treated with oxytocin to induce labor and with atosiban (an oxytocin antagonist) to arrest preterm labor. A prospective study with two cohorts: 14 pregnant women treated with atosiban for premature uterine contractions, and 28 women undergoing induction of labor with oxytocin. Computerized analyses of the electrocardiogram were performed with spectral and nonlinear dynamic analyses. Atosiban did not alter any of the variables associated with heart rate variability, whereas oxytocin showed a dose-dependent decrease in heart rate (p < 0.05) and a significant increase in all spectral variables studied (p < 0.01). Atosiban has no adverse effects on the cardiovascular system or the modulation of heart rate. Oxytocin, on the other hand, can cause a dose-dependent bradycardic effect and an increase in the spectral power, thus should be used with caution in certain pregnant women.

  18. Seasonal modulation of the 7Be solar neutrino rate in Borexino

    NASA Astrophysics Data System (ADS)

    Agostini, M.; Altenmüller, K.; Appel, S.; Atroshchenko, V.; Basilico, D.; Bellini, G.; Benziger, J.; Bick, D.; Bonfini, G.; Borodikhina, L.; Bravo, D.; Caccianiga, B.; Calaprice, F.; Caminata, A.; Caprioli, S.; Carlini, M.; Cavalcante, P.; Chepurnov, A.; Choi, K.; D'Angelo, D.; Davini, S.; Derbin, A.; Ding, X. F.; Di Noto, L.; Drachnev, I.; Fomenko, K.; Franco, D.; Froborg, F.; Gabriele, F.; Galbiati, C.; Ghiano, C.; Giammarchi, M.; Goeger-Neff, M.; Goretti, A.; Gromov, M.; Hagner, C.; Houdy, T.; Hungerford, E.; Ianni, Aldo; Ianni, Andrea; Jany, A.; Jeschke, D.; Kobychev, V.; Korablev, D.; Korga, G.; Kryn, D.; Laubenstein, M.; Lehnert, B.; Litvinovich, E.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Manecki, S.; Manuzio, G.; Marcocci, S.; Martyn, J.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Montuschi, M.; Muratova, V.; Neumair, B.; Oberauer, L.; Opitz, B.; Ortica, F.; Pallavicini, M.; Papp, L.; Pocar, A.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Roncin, R.; Rossi, N.; Schönert, S.; Semenov, D.; Shakina, P.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Stokes, L. F. F.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Thurn, J.; Toropova, M.; Unzhakov, E.; Vishneva, A.; Vogelaar, R. B.; von Feilitzsch, F.; Wang, H.; Weinz, S.; Wojcik, M.; Wurm, M.; Yokley, Z.; Zaimidoroga, O.; Zavatarelli, S.; Zuber, K.; Zuzel, G.

    2017-06-01

    We present the evidence for the seasonal modulation of the 7Be neutrino interaction rate with the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy. The period, amplitude, and phase of the observed time evolution of the signal are consistent with its solar origin, and the absence of an annual modulation is rejected at 99.99% C.L. The data are analyzed using three methods: the analytical fit to event rate, the Lomb-Scargle and the Empirical Mode Decomposition techniques, which all yield results in excellent agreement.

  19. Sensitivity to temporal modulation rate and spectral bandwidth in the human auditory system: MEG evidence.

    PubMed

    Wang, Yadong; Ding, Nai; Ahmar, Nayef; Xiang, Juanjuan; Poeppel, David; Simon, Jonathan Z

    2012-04-01

    Slow acoustic modulations below 20 Hz, of varying bandwidths, are dominant components of speech and many other natural sounds. The dynamic neural representations of these modulations are difficult to study through noninvasive neural-recording methods, however, because of the omnipresent background of slow neural oscillations throughout the brain. We recorded the auditory steady-state responses (aSSR) to slow amplitude modulations (AM) from 14 human subjects using magnetoencephalography. The responses to five AM rates (1.5, 3.5, 7.5, 15.5, and 31.5 Hz) and four types of carrier (pure tone and 1/3-, 2-, and 5-octave pink noise) were investigated. The phase-locked aSSR was detected reliably in all conditions. The response power generally decreases with increasing modulation rate, and the response latency is between 100 and 150 ms for all but the highest rates. Response properties depend only weakly on the bandwidth. Analysis of the complex-valued aSSR magnetic fields in the Fourier domain reveals several neural sources with different response phases. These neural sources of the aSSR, when approximated by a single equivalent current dipole (ECD), are distinct from and medial to the ECD location of the N1m response. These results demonstrate that the globally synchronized activity in the human auditory cortex is phase locked to slow temporal modulations below 30 Hz, and the neural sensitivity decreases with an increasing AM rate, with relative insensitivity to bandwidth.

  20. Disturbances of motor unit rate modulation are prevalent in muscles of spastic-paretic stroke survivors.

    PubMed

    Mottram, C J; Heckman, C J; Powers, R K; Rymer, W Z; Suresh, N L

    2014-05-01

    Stroke survivors often exhibit abnormally low motor unit firing rates during voluntary muscle activation. Our purpose was to assess the prevalence of saturation in motor unit firing rates in the spastic-paretic biceps brachii muscle of stroke survivors. To achieve this objective, we recorded the incidence and duration of impaired lower- and higher-threshold motor unit firing rate modulation in spastic-paretic, contralateral, and healthy control muscle during increases in isometric force generated by the elbow flexor muscles. Impaired firing was considered to have occurred when firing rate became constant (i.e., saturated), despite increasing force. The duration of impaired firing rate modulation in the lower-threshold unit was longer for spastic-paretic (3.9 ± 2.2 s) than for contralateral (1.4 ± 0.9 s; P < 0.001) and control (1.1 ± 1.0 s; P = 0.005) muscles. The duration of impaired firing rate modulation in the higher-threshold unit was also longer for the spastic-paretic (1.7 ± 1.6 s) than contralateral (0.3 ± 0.3 s; P = 0.007) and control (0.1 ± 0.2 s; P = 0.009) muscles. This impaired firing rate of the lower-threshold unit arose, despite an increase in the overall descending command, as shown by the recruitment of the higher-threshold unit during the time that the lower-threshold unit was saturating, and by the continuous increase in averages of the rectified EMG of the biceps brachii muscle throughout the rising phase of the contraction. These results suggest that impairments in firing rate modulation are prevalent in motor units of spastic-paretic muscle, even when the overall descending command to the muscle is increasing.

  1. Disturbances of motor unit rate modulation are prevalent in muscles of spastic-paretic stroke survivors

    PubMed Central

    Heckman, C. J.; Powers, R. K.; Rymer, W. Z.; Suresh, N. L.

    2014-01-01

    Stroke survivors often exhibit abnormally low motor unit firing rates during voluntary muscle activation. Our purpose was to assess the prevalence of saturation in motor unit firing rates in the spastic-paretic biceps brachii muscle of stroke survivors. To achieve this objective, we recorded the incidence and duration of impaired lower- and higher-threshold motor unit firing rate modulation in spastic-paretic, contralateral, and healthy control muscle during increases in isometric force generated by the elbow flexor muscles. Impaired firing was considered to have occurred when firing rate became constant (i.e., saturated), despite increasing force. The duration of impaired firing rate modulation in the lower-threshold unit was longer for spastic-paretic (3.9 ± 2.2 s) than for contralateral (1.4 ± 0.9 s; P < 0.001) and control (1.1 ± 1.0 s; P = 0.005) muscles. The duration of impaired firing rate modulation in the higher-threshold unit was also longer for the spastic-paretic (1.7 ± 1.6 s) than contralateral (0.3 ± 0.3 s; P = 0.007) and control (0.1 ± 0.2 s; P = 0.009) muscles. This impaired firing rate of the lower-threshold unit arose, despite an increase in the overall descending command, as shown by the recruitment of the higher-threshold unit during the time that the lower-threshold unit was saturating, and by the continuous increase in averages of the rectified EMG of the biceps brachii muscle throughout the rising phase of the contraction. These results suggest that impairments in firing rate modulation are prevalent in motor units of spastic-paretic muscle, even when the overall descending command to the muscle is increasing. PMID:24572092

  2. Effects of stimulation rate, mode and level on modulation detection by cochlear implant users.

    PubMed

    Galvin, John J; Fu, Qian-Jie

    2005-09-01

    In cochlear implant (CI) patients, temporal processing is often poorest at low listening levels, making perception difficult for low-amplitude temporal cues that are important for consonant recognition and/or speech perception in noise. It remains unclear how speech processor parameters such as stimulation rate and stimulation mode may affect temporal processing, especially at low listening levels. The present study investigated the effects of these parameters on modulation detection by six CI users. Modulation detection thresholds (MDTs) were measured as functions of stimulation rate, mode, and level. Results show that for all stimulation rate and mode conditions, modulation sensitivity was poorest at quiet listening levels, consistent with results from previous studies. MDTs were better with the lower stimulation rate, especially for quiet-to-medium listening levels. Stimulation mode had no significant effect on MDTs. These results suggest that, although high stimulation rates may better encode temporal information and widen the electrode dynamic range, CI patients may not be able to access these enhanced temporal cues, especially at the lower portions of the dynamic range. Lower stimulation rates may provide better recognition of weak acoustic envelope information.

  3. Role of climate and vegetation density in modulating denudation rates in the Himalaya

    NASA Astrophysics Data System (ADS)

    Olen, Stephanie M.; Bookhagen, Bodo; Strecker, Manfred R.

    2016-07-01

    Vegetation has long been hypothesized to influence the nature and rates of surface processes. We test the possible impact of vegetation and climate on denudation rates at orogen scale by taking advantage of a pronounced along-strike gradient in rainfall and vegetation density in the Himalaya. We combine 12 new 10Be denudation rates from the Sutlej Valley and 123 published denudation rates from fluvially-dominated catchments in the Himalaya with remotely-sensed measures of vegetation density and rainfall metrics, and with tectonic and lithologic constraints. In addition, we perform topographic analyses to assess the contribution of vegetation and climate in modulating denudation rates along strike. We observe variations in denudation rates and the relationship between denudation and topography along strike that are most strongly controlled by local rainfall amount and vegetation density, and cannot be explained by along-strike differences in tectonics or lithology. A W-E along-strike decrease in denudation rate variability positively correlates with the seasonality of vegetation density (R = 0.95, p < 0.05), and negatively correlates with mean vegetation density (R = - 0.84, p < 0.05). Vegetation density modulates the topographic response to changing denudation rates, such that the functional relationship between denudation rate and topographic steepness becomes increasingly linear as vegetation density increases. We suggest that while tectonic processes locally control the pattern of denudation rates across strike of the Himalaya (i.e., S-N), along strike of the orogen (i.e., E-W) climate exerts a measurable influence on how denudation rates scatter around long-term, tectonically-controlled erosion, and on the functional relationship between topography and denudation.

  4. Rate-adaptive modulation and coding for optical fiber transmission systems

    NASA Astrophysics Data System (ADS)

    Gho, Gwang-Hyun; Kahn, Joseph M.

    2011-01-01

    Rate-adaptive optical transmission techniques adjust information bit rate based on transmission distance and other factors affecting signal quality. These techniques enable increased bit rates over shorter links, while enabling transmission over longer links when regeneration is not available. They are likely to become more important with increasing network traffic and a continuing evolution toward optically switched mesh networks, which make signal quality more variable. We propose a rate-adaptive scheme using variable-rate forward error correction (FEC) codes and variable constellations with a fixed symbol rate, quantifying how achievable bit rates vary with distance. The scheme uses serially concatenated Reed-Solomon codes and an inner repetition code to vary the code rate, combined with singlecarrier polarization-multiplexed M-ary quadrature amplitude modulation (PM-M-QAM) with variable M and digital coherent detection. A rate adaptation algorithm uses the signal-to-noise ratio (SNR) or the FEC decoder input bit-error ratio (BER) estimated by a receiver to determine the FEC code rate and constellation size that maximizes the information bit rate while satisfying a target FEC decoder output BER and an SNR margin, yielding a peak rate of 200 Gbit/s in a nominal 50-GHz channel bandwidth. We simulate single-channel transmission through a long-haul fiber system incorporating numerous optical switches, evaluating the impact of fiber nonlinearity and bandwidth narrowing. With zero SNR margin, we achieve bit rates of 200/100/50 Gbit/s over distances of 650/2000/3000 km. Compared to an ideal coding scheme, the proposed scheme exhibits a performance gap ranging from about 6.4 dB at 650 km to 7.5 dB at 5000 km.

  5. Uncertainty estimation of spectral matching ratio based power rating of CPV modules

    NASA Astrophysics Data System (ADS)

    Steiner, Marc; Siefer, Gerald; Bett, Andreas W.

    2017-09-01

    The concentrator standard conditions are defined in the standard IEC 62670-1. Those conditions demand for spectral conditions equivalent to AM1.5d as described in IEC 60904-3. The power output of CPV modules has to be rated at the concentrator standard conditions and thus at AM1.5d spectral irradiance. According to IEC standard 62670-3 the prevailing spectral conditions have to be characterized using spectral matching ratios (SMR). The SMR values have to be within three percent of unity to allow for standardized power ratings. The SMR values are calculated from component cell sensor readings. The most commonly used component cells are based on lattice-matched triple-junction cell structures with bandgaps of 1.9, 1.4 and 0.7 eV. In this work, the usage of these component cells for power ratings on CPV modules equipped with other types of multi-junction cells is investigated. This investigation is based on representative power outputs of CPV modules. These power outputs were calculated using i) the spectral irradiance modeling software SMARTS2, ii) measured external quantum efficiencies and iii) the two-diode model. The outcome of this investigation is an estimation for the measurement uncertainty of rated CPV module power output when using the SMR filtering approach recommended in IEC 62670-3.

  6. Impact of a kiosk educational module on HIV screening rates and patient knowledge.

    PubMed

    Saifu, Hemen N; Shamouelian, Albert; Davis, Lisa G; Santana-Rios, Elizabeth; Goetz, Matthew Bidwell; Asch, Steven M; Sun, Benjamin C

    2011-01-01

    We assessed the effect of a kiosk educational module on HIV screening rates and patient knowledge about HIV testing. The evaluation was performed in a walk-in clinic offering routine HIV screening. During alternating two-week periods, patients were referred either to view a kiosk-based, educational module prior to receiving usual care, or the kiosk module was turned off and no alterations to care processes were made. The primary outcome was HIV testing rate. The secondary outcome was knowledge about HIV rapid screening, as measured with a questionnaire. There were 71 patients in the kiosk periods and 79 patients in the usual-care periods. The overall HIV testing rate was 41%. The kiosk period was not associated with greater odds of HIV testing (OR 0.7; 95% CI: 0.4-1.4). In 44 patients who completed the knowledge survey, the kiosk group was strongly associated with increased knowledge (predicted increase in knowledge score: 1.3; 95% CI: 036-2.1). The brief kiosk educational module did not improve HIV screening rates, but it increased overall patient knowledge about HIV testing.

  7. Model cerebellar granule cells can faithfully transmit modulated firing rate signals

    PubMed Central

    Rössert, Christian; Solinas, Sergio; D'Angelo, Egidio; Dean, Paul; Porrill, John

    2014-01-01

    A crucial assumption of many high-level system models of the cerebellum is that information in the granular layer is encoded in a linear manner. However, granule cells are known for their non-linear and resonant synaptic and intrinsic properties that could potentially impede linear signal transmission. In this modeling study we analyse how electrophysiological granule cell properties and spike sampling influence information coded by firing rate modulation, assuming no signal-related, i.e., uncorrelated inhibitory feedback (open-loop mode). A detailed one-compartment granule cell model was excited in simulation by either direct current or mossy-fiber synaptic inputs. Vestibular signals were represented as tonic inputs to the flocculus modulated at frequencies up to 20 Hz (approximate upper frequency limit of vestibular-ocular reflex, VOR). Model outputs were assessed using estimates of both the transfer function, and the fidelity of input-signal reconstruction measured as variance-accounted-for. The detailed granule cell model with realistic mossy-fiber synaptic inputs could transmit information faithfully and linearly in the frequency range of the vestibular-ocular reflex. This was achieved most simply if the model neurons had a firing rate at least twice the highest required frequency of modulation, but lower rates were also adequate provided a population of neurons was utilized, especially in combination with push-pull coding. The exact number of neurons required for faithful transmission depended on the precise values of firing rate and noise. The model neurons were also able to combine excitatory and inhibitory signals linearly, and could be replaced by a simpler (modified) integrate-and-fire neuron in the case of high tonic firing rates. These findings suggest that granule cells can in principle code modulated firing-rate inputs in a linear manner, and are thus consistent with the high-level adaptive-filter model of the cerebellar microcircuit. PMID:25352777

  8. Modulations of Heart Rate, ECG, and Cardio-Respiratory Coupling Observed in Polysomnography

    PubMed Central

    Penzel, Thomas; Kantelhardt, Jan W.; Bartsch, Ronny P.; Riedl, Maik; Kraemer, Jan F.; Wessel, Niels; Garcia, Carmen; Glos, Martin; Fietze, Ingo; Schöbel, Christoph

    2016-01-01

    The cardiac component of cardio-respiratory polysomnography is covered by ECG and heart rate recordings. However, their evaluation is often underrepresented in summarizing reports. As complements to EEG, EOG, and EMG, these signals provide diagnostic information for autonomic nervous activity during sleep. This review presents major methodological developments in sleep research regarding heart rate, ECG, and cardio-respiratory couplings in a chronological (historical) sequence. It presents physiological and pathophysiological insights related to sleep medicine obtained by new technical developments. Recorded nocturnal ECG facilitates conventional heart rate variability (HRV) analysis, studies of cyclical variations of heart rate, and analysis of ECG waveform. In healthy adults, the autonomous nervous system is regulated in totally different ways during wakefulness, slow-wave sleep, and REM sleep. Analysis of beat-to-beat heart-rate variations with statistical methods enables us to estimate sleep stages based on the differences in autonomic nervous system regulation. Furthermore, up to some degree, it is possible to track transitions from wakefulness to sleep by analysis of heart-rate variations. ECG and heart rate analysis allow assessment of selected sleep disorders as well. Sleep disordered breathing can be detected reliably by studying cyclical variation of heart rate combined with respiration-modulated changes in ECG morphology (amplitude of R wave and T wave). PMID:27826247

  9. Modulations of Heart Rate, ECG, and Cardio-Respiratory Coupling Observed in Polysomnography.

    PubMed

    Penzel, Thomas; Kantelhardt, Jan W; Bartsch, Ronny P; Riedl, Maik; Kraemer, Jan F; Wessel, Niels; Garcia, Carmen; Glos, Martin; Fietze, Ingo; Schöbel, Christoph

    2016-01-01

    The cardiac component of cardio-respiratory polysomnography is covered by ECG and heart rate recordings. However, their evaluation is often underrepresented in summarizing reports. As complements to EEG, EOG, and EMG, these signals provide diagnostic information for autonomic nervous activity during sleep. This review presents major methodological developments in sleep research regarding heart rate, ECG, and cardio-respiratory couplings in a chronological (historical) sequence. It presents physiological and pathophysiological insights related to sleep medicine obtained by new technical developments. Recorded nocturnal ECG facilitates conventional heart rate variability (HRV) analysis, studies of cyclical variations of heart rate, and analysis of ECG waveform. In healthy adults, the autonomous nervous system is regulated in totally different ways during wakefulness, slow-wave sleep, and REM sleep. Analysis of beat-to-beat heart-rate variations with statistical methods enables us to estimate sleep stages based on the differences in autonomic nervous system regulation. Furthermore, up to some degree, it is possible to track transitions from wakefulness to sleep by analysis of heart-rate variations. ECG and heart rate analysis allow assessment of selected sleep disorders as well. Sleep disordered breathing can be detected reliably by studying cyclical variation of heart rate combined with respiration-modulated changes in ECG morphology (amplitude of R wave and T wave).

  10. Evaluation and Field Assessment of Bifacial Photovoltaic Module Power Rating Methodologies

    SciTech Connect

    Deline, Chris; MacAlpine, Sara; Marion, Bill; Toor, Fatima; Asgharzadeh, Amir; Stein, Joshua S.

    2016-11-21

    1-sun power ratings for bifacial modules are currently undefined. This is partly because there is no standard definition of rear irradiance given 1000 Wm-2 on the front. Using field measurements and simulations, we evaluate multiple deployment scenarios for bifacial modules and provide details on the amount of irradiance that could be expected. A simplified case that represents a single module deployed under conditions consistent with existing 1-sun irradiance standards leads to a bifacial reference condition of 1000 Wm-2 Gfront and 130-140 Wm-2 Grear. For fielded systems of bifacial modules, Grear magnitude and spatial uniformity will be affected by self-shade from adjacent modules, varied ground cover, and ground-clearance height. A standard measurement procedure for bifacial modules is also currently undefined. A proposed international standard is under development, which provides the motivation for this work. Here, we compare outdoor field measurements of bifacial modules with irradiance on both sides with proposed indoor test methods where irradiance is only applied to one side at a time. The indoor method has multiple advantages, including controlled and repeatable irradiance and thermal environment, along with allowing the use of conventional single-sided flash test equipment. The comparison results are promising, showing that the indoor and outdoor methods agree within 1%-2% for multiple rear-irradiance conditions and bifacial module types.

  11. Evaluation and Field Assessment of Bifacial Photovoltaic Module Power Rating Methodologies: Preprint

    SciTech Connect

    Deline, Chris; MacAlpine, Sara; Marion, Bill; Toor, Fatima; Asgharzadeh, Amir; Stein, Joshua S.

    2016-06-16

    1-sun power ratings for bifacial modules are currently undefined. This is partly because there is no standard definition of rear irradiance given 1000 Wm-2 on the front. Using field measurements and simulations, we evaluate multiple deployment scenarios for bifacial modules and provide details on the amount of irradiance that could be expected. A simplified case that represents a single module deployed under conditions consistent with existing 1-sun irradiance standards leads to a bifacial reference condition of 1000 Wm-2 Gfront and 130-140 Wm-2 Grear. For fielded systems of bifacial modules, Grear magnitude and spatial uniformity will be affected by self-shade from adjacent modules, varied ground cover, and ground-clearance height. A standard measurement procedure for bifacial modules is also currently undefined. A proposed international standard is under development, which provides the motivation for this work. Here, we compare outdoor field measurements of bifacial modules with irradiance on both sides with proposed indoor test methods where irradiance is only applied to one side at a time. The indoor method has multiple advantages, including controlled and repeatable irradiance and thermal environment, along with allowing the use of conventional single-sided flash test equipment. The comparison results are promising, showing that the indoor and outdoor methods agree within 1%-2% for multiple rear-irradiance conditions and bifacial module types.

  12. Search for Event Rate Modulation in XENON100 Electronic Recoil Data

    NASA Astrophysics Data System (ADS)

    Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Anthony, M.; Arazi, L.; Arisaka, K.; Arneodo, F.; Balan, C.; Barrow, P.; Baudis, L.; Bauermeister, B.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Cardoso, J. M. R.; Cervantes, M.; Coderre, D.; Colijn, A. P.; Contreras, H.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; di Giovanni, A.; Duchovni, E.; Fattori, S.; Ferella, A. D.; Fieguth, A.; Fulgione, W.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Grignon, C.; Gross, E.; Hampel, W.; Hasterok, C.; Itay, R.; Kaether, F.; Kaminsky, B.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Le Calloch, M.; Lellouch, D.; Levinson, L.; Levy, C.; Lindemann, S.; Lindner, M.; Lopes, J. A. M.; Lyashenko, A.; Macmullin, S.; Marrodán Undagoitia, T.; Masbou, J.; Massoli, F. V.; Mayani, D.; Melgarejo Fernandez, A. J.; Meng, Y.; Messina, M.; Micheneau, K.; Miguez, B.; Molinario, A.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Orrigo, S. E. A.; Pakarha, P.; Persiani, R.; Piastra, F.; Pienaar, J.; Plante, G.; Priel, N.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; Dos Santos, J. M. F.; Sartorelli, G.; Schindler, S.; Schreiner, J.; Schumann, M.; Scotto Lavina, L.; Selvi, M.; Shagin, P.; Simgen, H.; Teymourian, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Wall, R.; Wang, H.; Weber, M.; Weinheimer, C.; Zhang, Y.; Xenon Collaboration

    2015-08-01

    We have searched for periodic variations of the electronic recoil event rate in the (2-6) keV energy range recorded between February 2011 and March 2012 with the XENON100 detector, adding up to 224.6 live days in total. Following a detailed study to establish the stability of the detector and its background contributions during this run, we performed an unbinned profile likelihood analysis to identify any periodicity up to 500 days. We find a global significance of less than 1 σ for all periods, suggesting no statistically significant modulation in the data. While the local significance for an annual modulation is 2.8 σ , the analysis of a multiple-scatter control sample and the phase of the modulation disfavor a dark matter interpretation. The DAMA/LIBRA annual modulation interpreted as a dark matter signature with axial-vector coupling of weakly interacting massive particles to electrons is excluded at 4.8 σ .

  13. CK2 activity is modulated by growth rate in Saccharomyces cerevisiae

    SciTech Connect

    Tripodi, Farida; Cirulli, Claudia; Reghellin, Veronica; Marin, Oriano; Brambilla, Luca; Schiappelli, Maria Patrizia; Porro, Danilo; Vanoni, Marco; Alberghina, Lilia; Coccetti, Paola

    2010-07-16

    Research highlights: {yields} CK2 subunits are nuclear both in glucose and in ethanol growing yeast cells. {yields} CK2 activity is modulated in S. cerevisiae. {yields} CK2 activity is higher in conditions supporting higher growth rates. {yields} V{sub max} is higher in faster growing cells, while K{sub m} is not affected. -- Abstract: CK2 is a highly conserved protein kinase controlling different cellular processes. It shows a higher activity in proliferating mammalian cells, in various types of cancer cell lines and tumors. The findings presented herein provide the first evidence of an in vivo modulation of CK2 activity, dependent on growth rate, in Saccharomyces cerevisiae. In fact, CK2 activity, assayed on nuclear extracts, is shown to increase in exponential growing batch cultures at faster growth rate, while localization of catalytic and regulatory subunits is not nutritionally modulated. Differences in intracellular CK2 activity of glucose- and ethanol-grown cells appear to depend on both increase in molecule number and k{sub cat}. Also in chemostat cultures nuclear CK2 activity is higher in faster growing cells providing the first unequivocal demonstration that growth rate itself can affect CK2 activity in a eukaryotic organism.

  14. The radiobiological effect of intra-fraction dose-rate modulation in intensity modulated radiation therapy (IMRT)

    NASA Astrophysics Data System (ADS)

    Bewes, J. M.; Suchowerska, N.; Jackson, M.; Zhang, M.; McKenzie, D. R.

    2008-07-01

    Intensity-modulated radiation therapy (IMRT) achieves optimal dose conformity to the tumor through the use of spatially and temporally modulated radiation fields. In particular, average dose rate and instantaneous dose rate (pulse amplitude) are highly variable within a single IMRT fraction. In this study we isolate these variables and determine their impact on cell survival. Survival was assessed using a clonogenic assay. Two cell lines of differing radiosensitivity were examined: melanoma (MM576) and non-small cell lung cancer (NCI-H460). The survival fraction was observed to be independent of instantaneous dose rate. A statistically significant trend to increased survival was observed as the average dose rate was decreased, for a constant total dose. The results are relevant to IMRT practice, where average treatment times can be significantly extended to allow for movement of the multi-leaf collimator (MLC). Our in vitro study adds to the pool of theoretical evidence for the consequences of protracted treatments. We find that extended delivery times can substantially increase the cell survival. This also suggests that regional variation in the dose-rate history across a tumor, which is inherent to IMRT, will affect radiation dose efficacy.

  15. Reinforcement magnitude modulation of rate dependent effects in pigeons and rats.

    PubMed

    Ginsburg, Brett C; Pinkston, Jonathan W; Lamb, R J

    2011-08-01

    Response rate can influence the behavioral effects of many drugs. Reinforcement magnitude may also influence drug effects. Further, reinforcement magnitude can influence rate-dependent effects. For example, in an earlier report, we showed that rate-dependent effects of two antidepressants depended on reinforcement magnitude. The ability of reinforcement magnitude to interact with rate-dependency has not been well characterized. It is not known whether our previous results are specific to antidepressants or generalize to other drug classes. Here, we further examine rate-magnitude interactions by studying effects of two stimulants (d-amphetamine [0.32-5.6 mg/kg] and cocaine [0.32-10 mg/kg]) and two sedatives (chlordiazepoxide [1.78-32 mg/kg] and pentobarbital [1.0-17.8 mg/kg]) in pigeons responding under a 3-component multiple fixed-interval (FI) 300-s schedule maintained by 2-, 4-, or 8-s of food access. We also examine the effects of d-amphetamine [0.32-3.2 mg/kg] and pentobarbital [1.8-10 mg/kg] in rats responding under a similar multiple FI300-s schedule maintained by 2- or 10- food pellet (45 mg) delivery. In pigeons, cocaine and, to a lesser extent, chlordiazepoxide exerted rate-dependent effects that were diminished by increasing durations of food access. The relationship was less apparent for pentobarbital, and not present for d-amphetamine. In rats, rate-dependent effects of pentobarbital and d-amphetamine were not modulated by reinforcement magnitude. In conclusion, some drugs appear to exert rate-dependent effect which are diminished when reinforcement magnitude is relatively high. Subsequent analysis of the rate-dependency data suggest the effects of reinforcement magnitude may be due to a diminution of drug-induced increases in low-rate behavior that occurs early in the fixed-interval.

  16. Spaceflight Ka-Band High-Rate Radiation-Hard Modulator

    NASA Technical Reports Server (NTRS)

    Jaso, Jeffery M.

    2011-01-01

    A document discusses the creation of a Ka-band modulator developed specifically for the NASA/GSFC Solar Dynamics Observatory (SDO). This flight design consists of a high-bandwidth, Quadriphase Shift Keying (QPSK) vector modulator with radiation-hardened, high-rate driver circuitry that receives I and Q channel data. The radiationhard design enables SDO fs Ka-band communications downlink system to transmit 130 Mbps (300 Msps after data encoding) of science instrument data to the ground system continuously throughout the mission fs minimum life of five years. The low error vector magnitude (EVM) of the modulator lowers the implementation loss of the transmitter in which it is used, thereby increasing the overall communication system link margin. The modulator comprises a component within the SDO transmitter, and meets the following specifications over a 0 to 40 C operational temperature range: QPSK/OQPSK modulator, 300-Msps symbol rate, 26.5-GHz center frequency, error vector magnitude less than or equal to 10 percent rms, and compliance with the NTIA (National Telecommunications and Information Administration) spectral mask.

  17. Search for Periodic Rate Variations in XENON100 and Comparison with DAMA/LIBRA Annual Modulation

    NASA Astrophysics Data System (ADS)

    Lin, Qing; Xenon Collaboration

    2017-01-01

    Three Scientific runs of XENON100 data accumulated from January 2010 to January 2014 are analyzed to search for electronic recoil event rate modulation signatures. An improved understanding of the detector stability and background has been achieved in this updated analysis. A profile likelihood method, which incorporates the improved detector stability and background model, is used to search for periodical signatures in the XENON100 electronic recoil events. The new results of these studies and a comparison with the DAMA/LIBRA annual modulation will be presented. We gratefully acknowledge continued support for the XENON Dark Matter program from the National Science Foundation.

  18. Digitally modulated bit error rate measurement system for microwave component evaluation

    NASA Technical Reports Server (NTRS)

    Shalkhauser, Mary Jo W.; Budinger, James M.

    1989-01-01

    The NASA Lewis Research Center has developed a unique capability for evaluation of the microwave components of a digital communication system. This digitally modulated bit-error-rate (BER) measurement system (DMBERMS) features a continuous data digital BER test set, a data processor, a serial minimum shift keying (SMSK) modem, noise generation, and computer automation. Application of the DMBERMS has provided useful information for the evaluation of existing microwave components and of design goals for future components. The design and applications of this system for digitally modulated BER measurements are discussed.

  19. Rate dependency of beta-adrenergic modulation of repolarizing currents in the guinea-pig ventricle.

    PubMed

    Rocchetti, M; Freli, V; Perego, V; Altomare, C; Mostacciuolo, G; Zaza, A

    2006-07-01

    Beta-adrenergic stimulation modulates ventricular currents and sinus cycle length (CL). We investigated how changes in CL affect the current induced by isoprenaline (Iso) during the action potential (AP) of guinea-pig ventricular myocytes. Action-potential clamp was applied at CLs of 250 and 1000 ms to measure: (1) the net current induced by 0.1 microm Iso (I(Iso)); (2) the L-type Ca2+ current I(CaL) and slow delayed rectifier current I(Ks) components of I(Iso) (I(IsoCa) and I(IsoK)), identified as the Iso-induced current sensitive to nifedipine and HMR1556, respectively; and (3) I(Iso) persisting after inhibition of both I(Ca) and I(Ks) (I(isoR)). The pause dependency of I(Ks) and its modulation were evaluated in voltage-clamp experiments. The rate dependency of the duration of the action potential at 90% repolarization (APD90) and its modulation by isoprenaline were tested in current-clamp experiments. At a CL of 250 ms I(Iso) was inward during initial repolarization and reversed at 59% of APD90. At a CL of 1000 ms I(Iso) became mostly inward in all cells. Switching to shorter CL did not change I(IsoCa) and I(IsoK) amplitudes, but moved their peak amplitudes to earlier repolarization; I(IsoR) was independent of CL. Acceleration of I(IsoK) at shorter CL was based on faster pause dependency of I(Ks) activation rate. The 'restitution' of activation rates was modulated by isoprenaline. The APD90-CL relation was rotated anticlockwise by isoprenaline and crossed the control curve at a CL of 150 ms (400 beats min(-1)). We conclude that: (1) isoprenaline induced markedly different current profiles according to pacing rate, involving CL-dependent I(Ca) and I(Ks) modulation; (2) the effect of isoprenaline on APD90 was CL dependent, and negligible during tachycardia; and (3) during sympathetic activation, repolarization stability may involve matched modulation of sinus rate and repolarizing currents.

  20. All-optical phase modulated format conversion for high transmission rates based on fiber nonlinearity

    NASA Astrophysics Data System (ADS)

    Duarte, Vanessa C.; Drummond, Miguel V.; Nogueira, Rogério N.

    2013-11-01

    Advanced modulation formats are an emerging area since they allow reducing the symbol rate while encoding more bits per symbol. This allows higher spectral efficiencies. In addition, we can achieve higher data rates using lower-speed equipment like in all-optical format conversion systems, an important step for the development of systems with high transmission rates. In this paper we study the impact of some impairments found in all-optical advanced format conversions based on cross phase modulation (XPM) on a highly nonlinear fiber (HNLF), such as amplified spontaneous emission (ASE), nonlinear fiber length and group velocity dispersion (GVD), and analyze its performance based on error vector magnitude (EVM) for different bitrate transmissions. This simulation study is applied on earlier proposed phase modulated format conversion where n nonreturn-to-zero on-off keying (NRZ-OOK) channels at 10 Gb/s are converted into a return-to-zero m phase shift keying (RZ-mPSK) at 20Gb/s. We extend the work with simulations and show the results for n NRZ-OOK channels at 20Gb/s, 40 Gb/s and 50Gb/s to RZ-PSK at 40Gb/s, 80 Gb/s and 100Gb/s, respectively.

  1. The modulation rate transfer function of a harbour porpoise (Phocoena phocoena).

    PubMed

    Linnenschmidt, Meike; Wahlberg, Magnus; Damsgaard Hansen, Janni

    2013-02-01

    During echolocation, toothed whales produce ultrasonic clicks at extremely rapid rates and listen for the returning echoes. The auditory brainstem response (ABR) duration was evaluated in terms of latency between single peaks: 5.5 ms (from peak I to VII), 3.4 ms (I-VI), and 1.4 ms (II-IV). In comparison to the killer whale and the bottlenose dolphin, the ABR of the harbour porpoise has shorter intervals between the peaks and consequently a shorter ABR duration. This indicates that the ABR duration and peak latencies are possibly related to the relative size of the auditory structures of the central nervous system and thus to the animal's size. The ABR to a sinusoidal amplitude modulated stimulus at 125 kHz (sensitivity threshold 63 dB re 1 μPa rms) was evaluated to determine the modulation rate transfer function of a harbour porpoise. The ABR showed distinct envelope following responses up to a modulation rate of 1,900 Hz. The corresponding calculated equivalent rectangular duration of 263 μs indicates a good temporal resolution in the harbour porpoise auditory system similar to the one for the bottlenose dolphin. The results explain how the harbour porpoise can follow clicks and echoes during echolocation with very short inter click intervals.

  2. Interactive coding of visual spatial frequency and auditory amplitude-modulation rate.

    PubMed

    Guzman-Martinez, Emmanuel; Ortega, Laura; Grabowecky, Marcia; Mossbridge, Julia; Suzuki, Satoru

    2012-03-06

    Spatial frequency is a fundamental visual feature coded in primary visual cortex, relevant for perceiving textures, objects, hierarchical structures, and scenes, as well as for directing attention and eye movements. Temporal amplitude-modulation (AM) rate is a fundamental auditory feature coded in primary auditory cortex, relevant for perceiving auditory objects, scenes, and speech. Spatial frequency and temporal AM rate are thus fundamental building blocks of visual and auditory perception. Recent results suggest that crossmodal interactions are commonplace across the primary sensory cortices and that some of the underlying neural associations develop through consistent multisensory experience such as audio-visually perceiving speech, gender, and objects. We demonstrate that people consistently and absolutely (rather than relatively) match specific auditory AM rates to specific visual spatial frequencies. We further demonstrate that this crossmodal mapping allows amplitude-modulated sounds to guide attention to and modulate awareness of specific visual spatial frequencies. Additional results show that the crossmodal association is approximately linear, based on physical spatial frequency, and generalizes to tactile pulses, suggesting that the association develops through multisensory experience during manual exploration of surfaces. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Modulation of microsaccade rate by task difficulty revealed through between- and within-trial comparisons.

    PubMed

    Gao, Xin; Yan, Hongmei; Sun, Hong-Jin

    2015-03-04

    Microsaccades (MSs) are small eye movements that occur during attempted visual fixation. While most studies concerning MSs focus on their roles in visual processing, some also suggest that the MS rate can be modulated by the amount of mental exertion involved in nonvisual processing. The current study focused on the effects of task difficulty on MS rate in a nonvisual mental arithmetic task. Experiment 1 revealed a general inverse relationship between MS rate and subjective task difficulty. During Experiment 2, three task phases with different requirements were identified: during calculation (between stimulus presentation and response), postcalculation (after reporting an answer), and a control condition (undergoing a matching sequence of events without the need to make a calculation). MS rate was observed to approximately double from the during-calculation phase to the postcalculation phase, and was significantly higher in the control condition compared to postcalculation. Only during calculation was the MS rate generally decreased with greater task difficulty. Our results suggest that the nonvisual cognitive processing can suppress MS rate, and that the extent of such suppression is related to the task difficulty.

  4. Nitric oxide modulates the discharge rate of basal forebrain neurones: a study in freely moving rats.

    PubMed

    Kostin, Andrey; Stenberg, Dag; Porkka-Heiskanen, Tarja

    2009-12-01

    In urethane-anaesthetized rats the infusion of a nitric oxide (NO)-donor [NOC-18, 1 mM (DETA/NO); 2,2'-(hydroxynitrosohydrazino)bis-ethanamine)] into the basal forebrain (BF) inhibited the discharge rate of most neurones, suggesting that NO may promote sleep via inhibition of wake-promoting neurones in the BF. However, this hypothesis still needs to be confirmed in freely moving rats. The objective of this study was to examine whether NO modulates the discharge rate of BF neurones in freely moving rats in a similar manner to anaesthetized rats. We measured the discharge rates of BF neurones in freely moving rats during microdialysis infusion of a NO-donor (1 mm; NOC-18) in different vigilance states. Neurones were characterized as wake (W)-on (51.8%), W-off (28.6%) and W/non-rapid eye movement (REM)-independent (21.4%) based on their discharge profiles during wakefulness (W) and non-REM sleep. The NO-donor affected the discharge rate of most BF neurones during quiet wakefulness (QW; 55%) and non-REM sleep (64%). The most prominent response in all neuronal groups was a decrease in the discharge rate during QW and non-REM sleep. A small subpopulation of neurones increased the discharge rate. The increase in NO in the BF during prolonged wakefulness may facilitate sleep via inhibition of wake-promoting neurones.

  5. Inter-island optical link demonstration using high-data-rate pulse-position modulation

    NASA Astrophysics Data System (ADS)

    Bacher, Michael; Arnold, Felix; Thieme, Björn

    2014-03-01

    The growing data-rate demand on satellite communication systems has led to the increased interest in optical space communication solutions for uplinks and downlinks between satellites and ground stations. As one example for applications that benefit from higher data-rates offered by optical links, RUAG Space studied an uplink scenario from an Unmanned Aerial Vehicle (UAV) to a Geostationary Orbit (GEO), under the European Space Agency project formally known as "Optical Communications Transceiver for Atmospheric Links" (OCTAL). Particularly suitable for optical links through turbulent atmospheres are robust Pulse Position Modulation (PPM) schemes. Communication electronics using a Multi-Pulse PPM (MPPM) scheme have been developed, increasing the data-rate compared to traditional PPM at a constant peak-to-average ratio while allowing a widely configurable data-rate range. The communication system was tested together with a newly developed receiver and transmitter at a wavelength of 1055nm in a field test campaign on the Canary Islands, where the transmitter telescope was located on La Palma while the receiver was installed within the ESA Optical Ground Station on Tenerife. The nearly horizontal link between the two islands with a link distance of 142km allowed validation of relevant system performances under stringent atmospheric conditions. A data-rate of more than 360Mbps could be demonstrated using MPPM, while nearly 220Mbps could be achieved with traditional PPM, well exceeding the targeted data-rate of the studied UAV-to-GEO scenario. Following an introduction on the applied MPPM schemes, the architecture of the test setup is described, different modulation schemes are compared and the test results of this Inter-Island Test Campaign performed in October 2012 are presented.

  6. Serial-Turbo-Trellis-Coded Modulation with Rate-1 Inner Code

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Sam; Pollara, Fabrizio

    2004-01-01

    Serially concatenated turbo codes have been proposed to satisfy requirements for low bit- and word-error rates and for low (in comparison with related previous codes) complexity of coding and decoding algorithms and thus low complexity of coding and decoding circuitry. These codes are applicable to such high-level modulations as octonary phase-shift keying (8PSK) and 16-state quadrature amplitude modulation (16QAM); the signal product obtained by applying one of these codes to one of these modulations is denoted, generally, as serially concatenated trellis-coded modulation (SCTCM). These codes could be particularly beneficial for communication systems that must be designed and operated subject to limitations on bandwidth and power. Some background information is prerequisite to a meaningful summary of this development. Trellis-coded modulation (TCM) is now a well-established technique in digital communications. A turbo code combines binary component codes (which typically include trellis codes) with interleaving. A turbo code of the type that has been studied prior to this development is composed of parallel concatenated convolutional codes (PCCCs) implemented by two or more constituent systematic encoders joined through one or more interleavers. The input information bits feed the first encoder and, after having been scrambled by the interleaver, enter the second encoder. A code word of a parallel concatenated code consists of the input bits to the first encoder followed by the parity check bits of both encoders. The suboptimal iterative decoding structure for such a code is modular, and consists of a set of concatenated decoding modules one for each constituent code connected through an interleaver identical to the one in the encoder side. Each decoder performs weighted soft decoding of the input sequence. PCCCs yield very large coding gains at the cost of a reduction in the data rate and/or an increase in bandwidth.

  7. Assessment of bifacial photovoltaic module power rating methodologies–inside and out

    DOE PAGES

    Deline, Chris; MacAlpine, Sara; Marion, Bill; ...

    2017-01-26

    One-sun power ratings for bifacial modules are currently undefined. This is partly because there is no standard definition of rear irradiance given 1000 W·m-2 on the front. Using field measurements and simulations, we evaluate multiple deployment scenarios for bifacial modules and provide details on the amount of irradiance that could be expected. A simplified case that represents a single module deployed under conditions consistent with existing one-sun irradiance standards lead to a bifacial reference condition of 1000 W·m-2 Gfront and 130-140 W·m-2 Grear. For fielded systems of bifacial modules, Grear magnitude and spatial uniformity will be affected by self-shade frommore » adjacent modules, varied ground cover, and ground-clearance height. A standard measurement procedure for bifacial modules is also currently undefined. A proposed international standard is under development, which provides the motivation for this paper. Here, we compare field measurements of bifacial modules under natural illumination with proposed indoor test methods, where irradiance is only applied to one side at a time. The indoor method has multiple advantages, including controlled and repeatable irradiance and thermal environment, along with allowing the use of conventional single-sided flash test equipment. The comparison results are promising, showing that indoor and outdoor methods agree within 1%-2% for multiple rear-irradiance conditions and bifacial module construction. Furthermore, a comparison with single-diode theory also shows good agreement to indoor measurements, within 1%-2% for power and other current-voltage curve parameters.« less

  8. Sensitivity to temporal modulation rate and spectral bandwidth in the human auditory system: fMRI evidence.

    PubMed

    Overath, Tobias; Zhang, Yue; Sanes, Dan H; Poeppel, David

    2012-04-01

    Hierarchical models of auditory processing often posit that optimal stimuli, i.e., those eliciting a maximal neural response, will increase in bandwidth and decrease in modulation rate as one ascends the auditory neuraxis. Here, we tested how bandwidth and modulation rate interact at several loci along the human central auditory pathway using functional MRI in a cardiac-gated, sparse acquisition design. Participants listened passively to both narrowband (NB) and broadband (BB) carriers (1/4- or 4-octave pink noise), which were jittered about a mean sinusoidal amplitude modulation rate of 0, 3, 29, or 57 Hz. The jittering was introduced to minimize stimulus-specific adaptation. The results revealed a clear difference between spectral bandwidth and temporal modulation rate: sensitivity to bandwidth (BB > NB) decreased from subcortical structures to nonprimary auditory cortex, whereas sensitivity to slow modulation rates was largest in nonprimary auditory cortex and largely absent in subcortical structures. Furthermore, there was no parametric interaction between bandwidth and modulation rate. These results challenge simple hierarchical models, in that BB stimuli evoked stronger responses in primary auditory cortex (and subcortical structures) rather than nonprimary cortex. Furthermore, the strong preference for slow modulation rates in nonprimary cortex demonstrates the compelling global sensitivity of auditory cortex to modulation rates that are dominant in the principal signals that we process, e.g., speech.

  9. Sensitivity to temporal modulation rate and spectral bandwidth in the human auditory system: fMRI evidence

    PubMed Central

    Zhang, Yue; Sanes, Dan H.; Poeppel, David

    2012-01-01

    Hierarchical models of auditory processing often posit that optimal stimuli, i.e., those eliciting a maximal neural response, will increase in bandwidth and decrease in modulation rate as one ascends the auditory neuraxis. Here, we tested how bandwidth and modulation rate interact at several loci along the human central auditory pathway using functional MRI in a cardiac-gated, sparse acquisition design. Participants listened passively to both narrowband (NB) and broadband (BB) carriers (1/4- or 4-octave pink noise), which were jittered about a mean sinusoidal amplitude modulation rate of 0, 3, 29, or 57 Hz. The jittering was introduced to minimize stimulus-specific adaptation. The results revealed a clear difference between spectral bandwidth and temporal modulation rate: sensitivity to bandwidth (BB > NB) decreased from subcortical structures to nonprimary auditory cortex, whereas sensitivity to slow modulation rates was largest in nonprimary auditory cortex and largely absent in subcortical structures. Furthermore, there was no parametric interaction between bandwidth and modulation rate. These results challenge simple hierarchical models, in that BB stimuli evoked stronger responses in primary auditory cortex (and subcortical structures) rather than nonprimary cortex. Furthermore, the strong preference for slow modulation rates in nonprimary cortex demonstrates the compelling global sensitivity of auditory cortex to modulation rates that are dominant in the principal signals that we process, e.g., speech. PMID:22298830

  10. Search for Electronic Recoil Event Rate Modulation with 4 Years of XENON100 Data.

    PubMed

    Aprile, E; Aalbers, J; Agostini, F; Alfonsi, M; Amaro, F D; Anthony, M; Arneodo, F; Barrow, P; Baudis, L; Bauermeister, B; Benabderrahmane, M L; Berger, T; Breur, P A; Brown, A; Brown, E; Bruenner, S; Bruno, G; Budnik, R; Bütikofer, L; Calvén, J; Cardoso, J M R; Cervantes, M; Cichon, D; Coderre, D; Colijn, A P; Conrad, J; Cussonneau, J P; Decowski, M P; de Perio, P; Di Gangi, P; Di Giovanni, A; Diglio, S; Eurin, G; Fei, J; Ferella, A D; Fieguth, A; Franco, D; Fulgione, W; Gallo Rosso, A; Galloway, M; Gao, F; Garbini, M; Geis, C; Goetzke, L W; Greene, Z; Grignon, C; Hasterok, C; Hogenbirk, E; Itay, R; Kaminsky, B; Kessler, G; Kish, A; Landsman, H; Lang, R F; Lellouch, D; Levinson, L; Lin, Q; Lindemann, S; Lindner, M; Lopes, J A M; Manfredini, A; Maris, I; Marrodán Undagoitia, T; Masbou, J; Massoli, F V; Masson, D; Mayani, D; Messina, M; Micheneau, K; Miguez, B; Molinario, A; Murra, M; Naganoma, J; Ni, K; Oberlack, U; Pakarha, P; Pelssers, B; Persiani, R; Piastra, F; Pienaar, J; Pizzella, V; Piro, M-C; Plante, G; Priel, N; Rauch, L; Reichard, S; Reuter, C; Rizzo, A; Rosendahl, S; Rupp, N; Dos Santos, J M F; Sartorelli, G; Scheibelhut, M; Schindler, S; Schreiner, J; Schumann, M; Scotto Lavina, L; Selvi, M; Shagin, P; Silva, M; Simgen, H; Sivers, M V; Stein, A; Thers, D; Tiseni, A; Trinchero, G; Tunnell, C; Wang, H; Wei, Y; Weinheimer, C; Wulf, J; Ye, J; Zhang, Y

    2017-03-10

    We report on a search for electronic recoil event rate modulation signatures in the XENON100 data accumulated over a period of 4 yr, from January 2010 to January 2014. A profile likelihood method, which incorporates the stability of the XENON100 detector and the known electronic recoil background model, is used to quantify the significance of periodicity in the time distribution of events. There is a weak modulation signature at a period of 431_{-14}^{+16} day in the low energy region of (2.0-5.8) keV in the single scatter event sample, with a global significance of 1.9σ; however, no other more significant modulation is observed. The significance of an annual modulation signature drops from 2.8σ, from a previous analysis of a subset of this data, to 1.8σ with all data combined. Single scatter events in the low energy region are thus used to exclude the DAMA/LIBRA annual modulation as being due to dark matter electron interactions via axial vector coupling at 5.7σ.

  11. Search for Electronic Recoil Event Rate Modulation with 4 Years of XENON100 Data

    NASA Astrophysics Data System (ADS)

    Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Arneodo, F.; Barrow, P.; Baudis, L.; Bauermeister, B.; Benabderrahmane, M. L.; Berger, T.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cervantes, M.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; di Gangi, P.; di Giovanni, A.; Diglio, S.; Eurin, G.; Fei, J.; Ferella, A. D.; Fieguth, A.; Franco, D.; Fulgione, W.; Gallo Rosso, A.; Galloway, M.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Greene, Z.; Grignon, C.; Hasterok, C.; Hogenbirk, E.; Itay, R.; Kaminsky, B.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Lellouch, D.; Levinson, L.; Lin, Q.; Lindemann, S.; Lindner, M.; Lopes, J. A. M.; Manfredini, A.; Maris, I.; Marrodán Undagoitia, T.; Masbou, J.; Massoli, F. V.; Masson, D.; Mayani, D.; Messina, M.; Micheneau, K.; Miguez, B.; Molinario, A.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Pakarha, P.; Pelssers, B.; Persiani, R.; Piastra, F.; Pienaar, J.; Pizzella, V.; Piro, M.-C.; Plante, G.; Priel, N.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; Rupp, N.; Dos Santos, J. M. F.; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schreiner, J.; Schumann, M.; Scotto Lavina, L.; Selvi, M.; Shagin, P.; Silva, M.; Simgen, H.; Sivers, M. V.; Stein, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Wang, H.; Wei, Y.; Weinheimer, C.; Wulf, J.; Ye, J.; Zhang, Y.; Xenon Collaboration

    2017-03-01

    We report on a search for electronic recoil event rate modulation signatures in the XENON100 data accumulated over a period of 4 yr, from January 2010 to January 2014. A profile likelihood method, which incorporates the stability of the XENON100 detector and the known electronic recoil background model, is used to quantify the significance of periodicity in the time distribution of events. There is a weak modulation signature at a period of 43 1-14+16 day in the low energy region of (2.0-5.8) keV in the single scatter event sample, with a global significance of 1.9 σ ; however, no other more significant modulation is observed. The significance of an annual modulation signature drops from 2.8 σ , from a previous analysis of a subset of this data, to 1.8 σ with all data combined. Single scatter events in the low energy region are thus used to exclude the DAMA/LIBRA annual modulation as being due to dark matter electron interactions via axial vector coupling at 5.7 σ .

  12. Attentional modulation of firing rate varies with burstiness across putative pyramidal neurons in macaque visual area V4.

    PubMed

    Anderson, Emily B; Mitchell, Jude F; Reynolds, John H

    2011-07-27

    One of the most well established forms of attentional modulation is an increase in firing rate when attention is directed into the receptive field of a neuron. The degree of rate modulation, however, can vary considerably across individual neurons, especially among broad spiking neurons (putative pyramids). We asked whether this heterogeneity might be correlated with a neuronal response property that is used in intracellular recording studies to distinguish among distinct neuronal classes: the burstiness of the neuronal spike train. We first characterized the burst spiking behavior of visual area V4 neurons and found that this varies considerably across the population, but we did not find evidence for distinct classes of burst behavior. Burstiness did, however, vary more widely across the class of neurons that shows the greatest heterogeneity in attentional modulation, and within that class, burstiness helped account for differences in attentional modulation. Among these broad spiking neurons, rate modulation was primarily restricted to bursty neurons, which as a group showed a highly significant increase in firing rate with attention. Furthermore, every bursty broad spiking neuron whose firing rate was significantly modulated by attention exhibited an increase in firing rate. In contrast, non-bursty broad spiking neurons exhibited no net attentional modulation, and, although some individual neurons did show significant rate modulation, these were divided among neurons showing increases and decreases. These findings show that macaque area V4 shows a range of bursting behavior and that the heterogeneity of attentional modulation can be explained, in part, by variation in burstiness.

  13. Effect of injection rate on contrast-enhanced MR angiography image quality: Modulation transfer function analysis.

    PubMed

    Clark, Toshimasa J; Wilson, Gregory J; Maki, Jeffrey H

    2017-07-01

    Contrast-enhanced (CE)-MRA optimization involves interactions of sequence duration, bolus timing, contrast recirculation, and both R1 relaxivity and R2*-related reduction of signal. Prior data suggest superior image quality with slower gadolinium injection rates than typically used. A computer-based model of CE-MRA was developed, with contrast injection, physiologic, and image acquisition parameters varied over a wide gamut. Gadolinium concentration was derived using Verhoeven's model with recirculation, R1 and R2* calculated at each time point, and modulation transfer curves used to determine injection rates, resulting in optimal resolution and image contrast for renal and carotid artery CE-MRA. Validation was via a vessel stenosis phantom and example patients who underwent carotid CE-MRA with low effective injection rates. Optimal resolution for renal and carotid CE-MRA is achieved with injection rates between 0.5 to 0.9 mL/s and 0.2 to 0.3 mL/s, respectively, dependent on contrast volume. Optimal image contrast requires slightly faster injection rates. Expected signal-to-noise ratio varies with both contrast volume and cardiac output. Simulated vessel phantom and clinical carotid CE-MRA exams at an effective contrast injection rate of 0.4 to 0.5 mL/s demonstrate increased resolution. Optimal image resolution is achieved at intuitively low, effective injection rates (0.2-0.9 mL/s, dependent on imaging parameters and contrast injection volume). Magn Reson Med 78:357-369, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  14. Density of wild prey modulates lynx kill rates on free-ranging domestic sheep.

    PubMed

    Odden, John; Nilsen, Erlend B; Linnell, John D C

    2013-01-01

    Understanding the factors shaping the dynamics of carnivore-livestock conflicts is vital to facilitate large carnivore conservation in multi-use landscapes. We investigated how the density of their main wild prey, roe deer Capreolus capreolus, modulates individual Eurasian lynx Lynx lynx kill rates on free-ranging domestic sheep Ovis aries across a range of sheep and roe deer densities. Lynx kill rates on free-ranging domestic sheep were collected in south-eastern Norway from 1995 to 2011 along a gradient of different livestock and wild prey densities using VHF and GPS telemetry. We used zero-inflated negative binomial (ZINB) models including lynx sex, sheep density and an index of roe deer density as explanatory variables to model observed kill rates on sheep, and ranked the models based on their AICc values. The model including the effects of lynx sex and sheep density in the zero-inflation model and the effect of lynx sex and roe deer density in the negative binomial part received most support. Irrespective of sheep density and sex, we found the lowest sheep kill rates in areas with high densities of roe deer. As roe deer density decreased, males killed sheep at higher rates, and this pattern held for both high and low sheep densities. Similarly, females killed sheep at higher rates in areas with high densities of sheep and low densities of roe deer. However, when sheep densities were low females rarely killed sheep irrespective of roe deer density. Our quantification of depredation rates can be the first step towards establishing fairer compensation systems based on more accurate and area specific estimation of losses. This study demonstrates how we can use ecological theory to predict where losses of sheep will be greatest, and can be used to identify areas where mitigation measures are most likely to be needed.

  15. Density of Wild Prey Modulates Lynx Kill Rates on Free-Ranging Domestic Sheep

    PubMed Central

    Odden, John; Nilsen, Erlend B.; Linnell, John D. C.

    2013-01-01

    Understanding the factors shaping the dynamics of carnivore–livestock conflicts is vital to facilitate large carnivore conservation in multi-use landscapes. We investigated how the density of their main wild prey, roe deer Capreolus capreolus, modulates individual Eurasian lynx Lynx lynx kill rates on free-ranging domestic sheep Ovis aries across a range of sheep and roe deer densities. Lynx kill rates on free-ranging domestic sheep were collected in south-eastern Norway from 1995 to 2011 along a gradient of different livestock and wild prey densities using VHF and GPS telemetry. We used zero-inflated negative binomial (ZINB) models including lynx sex, sheep density and an index of roe deer density as explanatory variables to model observed kill rates on sheep, and ranked the models based on their AICc values. The model including the effects of lynx sex and sheep density in the zero-inflation model and the effect of lynx sex and roe deer density in the negative binomial part received most support. Irrespective of sheep density and sex, we found the lowest sheep kill rates in areas with high densities of roe deer. As roe deer density decreased, males killed sheep at higher rates, and this pattern held for both high and low sheep densities. Similarly, females killed sheep at higher rates in areas with high densities of sheep and low densities of roe deer. However, when sheep densities were low females rarely killed sheep irrespective of roe deer density. Our quantification of depredation rates can be the first step towards establishing fairer compensation systems based on more accurate and area specific estimation of losses. This study demonstrates how we can use ecological theory to predict where losses of sheep will be greatest, and can be used to identify areas where mitigation measures are most likely to be needed. PMID:24278123

  16. Feasibility study of volumetric modulated arc therapy with constant dose rate for endometrial cancer

    SciTech Connect

    Yang, Ruijie; Wang, Junjie; Xu, Feng; Li, Hua; Zhang, Xile

    2013-10-01

    To investigate the feasibility, efficiency, and delivery accuracy of volumetric modulated arc therapy with constant dose rate (VMAT-CDR) for whole-pelvic radiotherapy (WPRT) of endometrial cancer. The nine-field intensity-modulated radiotherapy (IMRT), VMAT with variable dose-rate (VMAT-VDR), and VMAT-CDR plans were created for 9 patients with endometrial cancer undergoing WPRT. The dose distribution of planning target volume (PTV), organs at risk (OARs), and normal tissue (NT) were compared. The monitor units (MUs) and treatment delivery time were also evaluated. For each VMAT-CDR plan, a dry run was performed to assess the dosimetric accuracy with MatriXX from IBA. Compared with IMRT, the VMAT-CDR plans delivered a slightly greater V{sub 20} of the bowel, bladder, pelvis bone, and NT, but significantly decreased the dose to the high-dose region of the rectum and pelvis bone. The MUs decreased from 1105 with IMRT to 628 with VMAT-CDR. The delivery time also decreased from 9.5 to 3.2 minutes. The average gamma pass rate was 95.6% at the 3%/3 mm criteria with MatriXX pretreatment verification for 9 patients. VMAT-CDR can achieve comparable plan quality with significant shorter delivery time and smaller number of MUs compared with IMRT for patients with endometrial cancer undergoing WPRT. It can be accurately delivered and be an alternative to IMRT on the linear accelerator without VDR capability.

  17. Autonomic modulation of heart rate in paraplegic wheelchair basketball players: Linear and nonlinear analysis.

    PubMed

    Zamunér, Antonio Roberto; Silva, Ester; Teodori, Rosana Macher; Catai, Aparecida Maria; Moreno, Marlene Aparecida

    2013-01-01

    This study aimed to evaluate the autonomic modulation of heart rate in sedentary paraplegics and paraplegic wheelchair basketball players with thoracic spinal cord injury below T6. Seven paraplegic wheelchair basketball players (active paraplegic group), five paraplegics who were not involved in regular exercise (sedentary paraplegic group) and 10 able-bodied participants (control group) took part in the study. The heart rate variability was evaluated by linear (low frequency and high frequency band in normalised units and low frequency/high frequency ratio) and nonlinear methods (Shannon entropy, corrected conditional entropy, and symbolic analysis). The sedentary group presented significantly higher values for low frequency, low frequency/high frequency ratio and symbolic index with no significant variations (0V%), and also lower values for the high frequency and symbolic index with two significant unlike variation (2ULV%) compared to active paraplegic group. Shannon entropy and corrected conditional entropy analyses revealed significantly lower values in the sedentary group than in the control or active paraplegic groups. Paraplegic individuals who regularly undertake physical exercise have higher complexity of R-R interval time series, lower sympathetic modulation, and higher parasympathetic modulation than sedentary paraplegic participants.

  18. Oxytocin receptor gene polymorphism modulates the effects of social support on heart rate variability

    PubMed Central

    Kanthak, Magdalena K.; Chen, Frances S.; Kumsta, Robert; Hill, LaBarron K.; Thayer, Julian F.; Heinrichs, Markus

    2017-01-01

    A large body of empirical research has demonstrated stress-buffering effects of social support. However, recent studies suggest that genetic variation of the oxytocin system (specifically, a common single nucleotide polymorphism, rs53576, of the oxytocin receptor gene) modulates the efficacy of social support. The timing and neurobiological basis of this genetic modulation were investigated using a standardized, laboratory-based psychological stress procedure (Trier Social Stress Test for Groups, TSST-G). To index potential stress buffering effects of social support mediated by the oxytocin system, heart rate variability (HRV) was obtained before and during the TSST-G from 40 healthy participants. Results indicate that social support is associated with higher HRV only in G allele carriers. Specifically, social support increased heart rate variability during direct social interaction and only in individuals with at least one copy of the G allele of rs53576. These findings support the idea that the stress-attenuating effects of social support are modulated by genetic variation of the oxytocin system. PMID:26903384

  19. Mean body temperature does not modulate eccrine sweat rate during upright tilt.

    PubMed

    Wilson, Thad E; Cui, Jian; Crandall, Craig G

    2005-04-01

    Conflicting reports exist about the role of baroreflexes in efferent control of eccrine sweat rate. These conflicting reports may be due to differing mean body temperatures between studies. The purpose of this project was to test the hypothesis that mean body temperature modulates the effect of head-up tilt on sweat rate and skin sympathetic nerve activity (SSNA). To address this question, mean body temperature (0.9.internal temperature + 0.1.mean skin temperature), SSNA (microneurography of peroneal nerve, n = 8), and sweat rate (from an area innervated by the peroneal nerve and from two forearm sites, one perfused with neostigmine to augment sweating at lower mean body temperatures and the second with the vehicle, n = 12) were measured in 13 subjects during multiple 30 degrees head-up tilts during whole body heating. At the end of the heat stress, mean body temperature (36.8 +/- 0.1 to 38.0 +/- 0.1 degrees C) and sweat rate at all sites were significantly elevated. No significant correlations were observed between mean body temperature and the change in SSNA during head-up tilt (r = 0.07; P = 0.62), sweating within the innervated area (r = 0.06; P = 0.56), sweating at the neostigmine treated site (r = 0.04; P = 0.69), or sweating at the control site (r = 0.01; P = 0.94). Also, for each tilt throughout the heat stress, there were no significant differences in sweat rate (final tilt sweat rates were 0.69 +/- 0.11 and 0.68 +/- 0.11 mg.cm(-2).min(-1) within the innervated area; 1.04 +/- 0.16 and 1.06 +/- 0.16 mg.cm(-2).min(-1) at the neostigmine-treated site; and 0.85 +/- 0.15 and 0.85 +/- 0.15 mg.cm(-2).min(-1) at the control site, for supine and tilt, respectively). Hence, these data indicate that mean body temperature does not modulate eccrine sweat rate during baroreceptor unloading induced via 30 degrees head-up tilt.

  20. Spin relaxation rates in quantum dots: Role of the phonon modulated spin orbit interaction

    NASA Astrophysics Data System (ADS)

    Alcalde, A. M.; Romano, C. L.; Marques, G. E.

    2008-11-01

    We calculate the spin relaxation rates in InAs and GaAs parabolic quantum dots due to the interaction of spin carriers with acoustical phonons. We consider a spin relaxation mechanism completely intrinsic to the system, since it is based on the modulation of the spin-orbit interaction by the acoustic phonon potential, which is independent of any structural properties of the confinement potential. The electron-phonon deformation potential and the piezoelectric interaction are described by the Pavlov-Firsov spin-phonon Hamiltonian. Our results demonstrate that, for narrow-gap semiconductors, the deformation potential interaction becomes dominant. This behavior is not observed for wide or intermediate gap semiconductors, where the piezoelectric coupling, in general, governs the relaxation processes. We also demonstrate that the spin relaxation rates are particularly sensitive to values of the Landé g-factor, which depend strongly on the spatial shape of the confinement.

  1. 60-GHz integrated-circuit high data rate quadriphase shift keying exciter and modulator

    NASA Technical Reports Server (NTRS)

    Grote, A.; Chang, K.

    1984-01-01

    An integrated-circuit quadriphase shift keying (QPSK) exciter and modulator have demonstrated excellent performance directly modulating a carrier frequency of 60 GHz with an output phase error of less than 3 degrees and maximum amplitude error of 0.5 dB. The circuit consists of a 60-GHz Gunn VCO phase-locked to a low-frequency reference source, a 4th subharmonic mixer, and a QPSK modlator packaged into a small volume of 1.8 x 2.5 x 0.35 in. The use of microstrip has the advantages of small size, light-weight, and low-cost fabrication. The unit has the potential for multigigabit data rate applications.

  2. A Pipelined IP Address Lookup Module for 100 Gbps Line Rates and beyond

    NASA Astrophysics Data System (ADS)

    Teuchert, Domenic; Hauger, Simon

    New Internet services and technologies call for higher packet switching capacities in the core network. Thus, a performance bottleneck arises at the backbone routers, as forwarding of Internet Protocol (IP) packets requires to search the most specific entry in a forwarding table that contains up to several hundred thousand address prefixes. The Tree Bitmap algorithm provides a well-balanced solution in respect of storage needs as well as of search and update complexity. In this paper, we present a pipelined lookup module based on this algorithm, which allows for an easy adaption to diverse protocol and hardware constraints. We determined the pipelining degree required to achieve the throughput for a 100 Gbps router line card by analyzing a representative sub-unit for various configured sizes. The module supports IPv4 and IPv6 configurations providing this throughput, as we determined the performance of our design to achieve a processing rate of 178 million packets per second.

  3. Search for Periodic Rate Variations in XENON100 and Comparison with DAMA/LIBRA Annual Modulation

    NASA Astrophysics Data System (ADS)

    Goetzke, Luke; Xenon Collaboration

    2015-04-01

    The stability of the XENON100 detector and electronic recoil event rate in the (2-6) keV energy range was studied for the 224.5 live-days of dark matter search data taken between February, 2011 and March, 2012. An un-binned profile likelihood analysis is used to identify potential periodic signatures in the electronic recoil data, with any period between 7 and 500 days. The results of these studies and a comparison with the DAMA/LIBRA annual modulation will be presented. We gratefully acknowledge the continued support of the XENON program by the National Science Foundation.

  4. Search for Periodic Rate Variations in XENON100 and Comparison with DAMA/LIBRA Annual Modulation

    NASA Astrophysics Data System (ADS)

    de Perio, Patrick; Xenon Collaboration

    2016-03-01

    The stability of the XENON100 detector and electronic recoil event rate in the (2-6) keV energy range was studied for 1 live-year of dark matter search data taken between February, 2011 and January, 2014. An un-binned profile likelihood analysis is used to identify potential periodic signatures in the electronic recoil data. The results of these studies and a comparison with the DAMA/LIBRA annual modulation will be presented. We gratefully acknowledge continued support for the XENON Dark Matter program from the National Science Foundation.

  5. High repetition rate optical switch using an electroabsorption modulator in TOAD configuration

    NASA Astrophysics Data System (ADS)

    Huo, Li; Yang, Yanfu; Lou, Caiyun; Gao, Yizhi

    2007-07-01

    A novel optical switch featured with high repetition rate, short switching window width, and high contrast ratio is proposed and demonstrated for the first time by placing an electroabsorption modulator (EAM) in a terahertz optical asymmetric demultiplexer (TOAD) configuration. The feasibility and main characteristics of the switch are investigated by numerical simulations and experiments. With this EAM-based TOAD, an error-free return-to-zero signal wavelength conversion with 0.62 dB power penalty at 20 Gbit/s is demonstrated.

  6. Perceptual-center modeling is affected by including acoustic rate-of-change modulations.

    PubMed

    Harsin, C A

    1997-02-01

    This study investigated the acoustic correlates of perceptual centers (p-centers) in CV and VC syllables and developed an acoustic p-center model. In Part 1, listeners located syllables' p-centers by a method-of-adjustment procedure. The CV syllables contained the consonants /s/,/r/,/n/,/t/,/d/,/k/, and /g/; the VCs, the consonants /s/,/r/, and /n/. The vowel in all syllables was /a/. The results of this experiment replicated and extended previous findings regarding the effects of phonetic variation on p-centers. In Part 2, a digital signal processing procedure was used to acoustically model p-center perception. Each stimulus was passed through a six-band digital filter, and the outputs were processed to derive low-frequency modulation components. These components were weighted according to a perceived modulation magnitude function and recombined to create six psychoacoustic envelopes containing modulation energies from 3 to 47 Hz. In this analysis, p-centers were found to be highly correlated with the time-weighted function of the rate-of-change in the psychoacoustic envelopes, multiplied by the psychoacoustic envelope magnitude increment. The results were interpreted as suggesting (1) the probable role of low-frequency energy modulations in p-center perception, and (2) the presence of perceptual processes that integrate multiple articulatory events into a single syllabic event.

  7. Weakly doped InP layers prepared by liquid phase epitaxy using a modulated cooling rate

    NASA Astrophysics Data System (ADS)

    Krukovskyi, R.; Mykhashchuk, Y.; Kost, Y.; Krukovskyi, S.; Saldan, I.

    2017-04-01

    Epitaxial structures based on InP are widely used to manufacture a number of devices such as microwave transistors, light-emitting diodes, lasers and Gunn diodes. However, their temporary instability caused by heterogeneity of resistivity along the layer thickness and the influence of various external or internal factors prompts the need for the development of a new reliable technology for their preparation. Weak doping by Yb, Al and Sn together with modulation of the cooling rate applied to prepare InP epitaxial layers is suggested to be adopted within the liquid phase epitaxy (LPE) method. The experimental results confirm the optimized conditions created to get a uniform electron concentration in the active n-InP layer. A sharp profile of electron concentration in the n+-InP(substrate)/n-InP/n+-InP epitaxial structure was observed experimentally at the proposed modulated cooling rate of 0.3 °С-1.5 °С min-1. The proposed technological method can be used to control the electrical and physical properties of InP epitaxial layers to be used in Gunn diodes.

  8. Experimental study on trace chemical contaminant generation rates of human metabolism in spacecraft crew module

    NASA Astrophysics Data System (ADS)

    Lihua, Guo; Xinxing, He; Guoxin, Xu; Xin, Qi

    2012-12-01

    Trace chemical contaminants generated by human metabolism is a major source of contamination in spacecraft crew module. In this research, types and generation rates of pollutants from human metabolism were determined in the Chinese diets. Expired air, skin gas, and sweat of 20 subjects were analyzed at different exercise states in a simulated module. The exercise states were designed according to the basic activities in the orbit of astronauts. Qualitative and quantitative analyses of contaminants generated by human metabolic were performed with gas chromatography/mass spectrometry, gas chromatography and UV spectrophotometer. Sixteen chemical compounds from metabolic sources were found. With the increase in physical load, the concentrations of chemical compounds from human skin and expired air correspondingly increased. The species and the offgassing rates of pollutants from human metabolism are different among the Chinese, Americans and the Russians due to differences in ethnicity and dietary customs. This research provides data to aid in the design, development and operation of China's long duration space mission.

  9. Increasing the information rates of optical communications via coded modulation: a study of transceiver performance

    PubMed Central

    Maher, Robert; Alvarado, Alex; Lavery, Domaniç; Bayvel, Polina

    2016-01-01

    Optical fibre underpins the global communications infrastructure and has experienced an astonishing evolution over the past four decades, with current commercial systems transmitting data rates in excess of 10 Tb/s over a single fibre core. The continuation of this dramatic growth in throughput has become constrained due to a power dependent nonlinear distortion arising from a phenomenon known as the Kerr effect. The mitigation of fibre nonlinearities is an area of intense research. However, even in the absence of nonlinear distortion, the practical limit on the transmission throughput of a single fibre core is dominated by the finite signal-to-noise ratio (SNR) afforded by current state-of-the-art coherent optical transceivers. Therefore, the key to maximising the number of information bits that can be reliably transmitted over a fibre channel hinges on the simultaneous optimisation of the modulation format and code rate, based on the SNR achieved at the receiver. In this work, we use an information theoretic approach based on the mutual information and the generalised mutual information to characterise a state-of-the-art dual polarisation m-ary quadrature amplitude modulation transceiver and subsequently apply this methodology to a 15-carrier super-channel to achieve the highest throughput (1.125 Tb/s) ever recorded using a single coherent receiver. PMID:26864633

  10. Sustained blood oxygenation and volume response to repetition rate-modulated sound in human auditory cortex.

    PubMed

    Seifritz, Erich; Di Salle, Francesco; Esposito, Fabrizio; Bilecen, Deniz; Neuhoff, John G; Scheffler, Klaus

    2003-10-01

    The blood oxygen level-dependent (BOLD) signal time course in the auditory cortex is characterized by two components, an initial transient peak and a subsequent sustained plateau with smaller amplitude. Because the T(2)(*) signal detected by functional magnetic resonance imaging (fMRI) depends on at least two counteracting factors, blood oxygenation and volume, we examined whether the reduction in the sustained BOLD signal results from decreased levels of oxygenation or from increased levels of blood volume. We used conventional fMRI to quantify the BOLD signal and fMRI in combination with superparamagnetic contrast agent to quantify blood volume and employed repetition rate-modulated sounds in a silent background to manipulate the response amplitude in the auditory cortex. In the BOLD signal, the initial peak reached 3.3% with pulsed sound and 1.9% with continuous sound, whereas the sustained BOLD signal fell to 2.2% with pulsed sound and to 0.5% with continuous sound, respectively. The repetition rate-dependent reduction in the sustained BOLD amplitude was accompanied by concordant changes in sustained blood volume levels, which, compared to silence, increased by approximately 30% with pulsed and by approximately 10% with continuous sound. Thus, our data suggest that the reduced amplitude of the sustained BOLD signal reflects stimulus-dependent modulation of blood oxygenation rather than blood volume-related effects.

  11. Augmenting data rate performance for higher order modulation in triangular index profile multicore fiber interconnect

    NASA Astrophysics Data System (ADS)

    Mishra, Jitendra K.; Priye, Vishnu; Rahman, B. M. A.

    2016-07-01

    A triangular profile multicore fiber (MCF) optical interconnect (OI) is investigated to augment performance that typically degrades at high data rates for higher order modulation in a short reach transmission system. Firstly, probability density functions (PDFs) variation with inter-core crosstalk is calculated for 8-core MCF OI with different index profile in the core and it was observed that the triangular profile MCF OI is the most crosstalk tolerant. Next, symbol error probability (SEP) for higher order quadrature phase shift keying (QPSK) modulated signal due to inter-core crosstalk is analytically obtained and their dependence on typical characteristic parameters are examined. Further, numerical simulations are carried out to compare the error performance of QPSK for step index and triangular index MCF OI by generating eye diagram at 40 Gbps per channel. Finally, it is shown that MCF OI with triangular index profile supporting QPSK has double spectral efficiency with tolerable trade off in SEP as compared with those of binary phase shift keying (BPSK) at high data rates which is scalable up to 5 Tbps.

  12. Rate of oxidative modification of cytochrome c by hydrogen peroxide is modulated by Hofmeister anions.

    PubMed

    Tomášková, Nataša; Varinská, Lenka; Sedlák, Erik

    2010-09-01

    Cytochrome c (cyt c) and other heme proteins are oxidatively modified in the presence of hydrogen peroxide in a concentration- and time-dependent manner. Cyt c modification has been monitored by several spectral probes by absorption spectroscopy (at wavelengths 410 nm, 530 nm), and circular dichroism (222, 268, 288 and 417 nm). Kinetics monitored with these spectral probes indicates that the oxidative modification of cyt c: i) proceeds in the order: heme --> aromatic amino acids --> secondary structure, and ii) the rate of the oxidative modification is proportional to the protein flexibility. The flexibility of cyt c was modulated by anions of Hofmeister series (sulfate, chloride, perchlorate) (Varhac et al. 2009). A minimalist scheme of the interaction of cyt c with hydrogen peroxide can be described by two steps: 1) interaction of hydrogen peroxide with heme iron forming the postulated ferryl intermediate, 2a) oxidation of another molecule of hydrogen peroxide and 2b) parallel oxidation of close amino acid residue(s) and/or heme. The catalase activity of cyt c is independent from the presence of Hofmeister anions, which indicates that both steps (1 and 2a) in the catalase reaction are independent from the flexibility of the heme region of the protein matrix. On the other hand, the flexibility of the polypeptide chain of the protein modulates the rate of parallel oxidative modification of the heme and amino acid residues.

  13. Packet error rate analysis of OOK, DPIM, and PPM modulation schemes for ground-to-satellite laser uplink communications.

    PubMed

    Jiang, Yijun; Tao, Kunyu; Song, Yiwei; Fu, Sen

    2014-03-01

    Performance of on-off keying (OOK), digital pulse interval modulation (DPIM), and pulse position modulation (PPM) schemes are researched for ground-to-satellite laser uplink communications. Packet error rates of these modulation systems are compared, with consideration of the combined effect of intensity fluctuation and beam wander. Based on the numerical results, performances of different modulation systems are discussed. Optimum divergence angle and transmitted beam radius of different modulation systems are indicated and the relations of the transmitted laser power to them are analyzed. This work can be helpful for modulation scheme selection and system design in ground-to-satellite laser uplink communications.

  14. Polarization-modulated second harmonic generation ellipsometric microscopy at video rate.

    PubMed

    DeWalt, Emma L; Sullivan, Shane Z; Schmitt, Paul D; Muir, Ryan D; Simpson, Garth J

    2014-08-19

    Fast 8 MHz polarization modulation coupled with analytical modeling, fast beam-scanning, and synchronous digitization (SD) have enabled simultaneous nonlinear optical Stokes ellipsometry (NOSE) and polarized laser transmittance imaging with image acquisition rates up to video rate. In contrast to polarimetry, in which the polarization state of the exiting beam is recorded, NOSE enables recovery of the complex-valued Jones tensor of the sample that describes all polarization-dependent observables of the measurement. Every video-rate scan produces a set of 30 images (10 for each detector with three detectors operating in parallel), each of which corresponds to a different polarization-dependent result. Linear fitting of this image set contracts it down to a set of five parameters for each detector in second harmonic generation (SHG) and three parameters for the transmittance of the incident beam. These parameters can in turn be used to recover the Jones tensor elements of the sample. Following validation of the approach using z-cut quartz, NOSE microscopy was performed for microcrystals of both naproxen and glucose isomerase. When weighted by the measurement time, NOSE microscopy was found to provide a substantial (>7 decades) improvement in the signal-to-noise ratio relative to our previous measurements based on the rotation of optical elements and a 3-fold improvement relative to previous single-point NOSE approaches.

  15. Hypnotizability-dependent modulation of the changes in heart rate control induced by upright stance.

    PubMed

    Santarcangelo, Enrica L; Balocchi, Rita; Scattina, Eliana; Manzoni, Diego; Bruschini, Luca; Ghelarducci, Brunello; Varanini, Maurizio

    2008-03-28

    Subjects with high (Highs) and low (Lows) susceptibility to hypnosis show differences in the sensory-motor integration for postural control and in the cardiovascular response to stress and experimental pain. Aim of the experiment was to assess whether the cardiac response to gravity-related stimulation depending on changes in the body position were different in the two groups. Thus, heart rate (HR) and heart rate variability (HRV) were evaluated in sitting and upright position in Highs and Lows. Position-related HRV changes were studied in the time (statistical indexes, Poincaré Plot) and frequency (spectral analysis) domain. Results indicated that upright stance was associated with similar changes in heart rate and different modulation of HRV in the two groups. The association of time and frequency domain analyses allowed hypothesizing different control mechanisms as responsible for the cardiac response to upright stance in Highs and Lows, likely due to a different role of the Very Low Frequency (VLF) spectral component of HRV in the two groups. The results are in line with previous findings indicating a natural protection of Highs against cardiovascular events and suggest that the Highs' cardiac function might be less impaired by microgravity than the Lows' one.

  16. Interactions between target location and reward size modulate the rate of microsaccades in monkeys.

    PubMed

    Joshua, Mati; Tokiyama, Stefanie; Lisberger, Stephen G

    2015-11-01

    We have studied how rewards modulate the occurrence of microsaccades by manipulating the size of an expected reward and the location of the cue that sets the expectations for future reward. We found an interaction between the size of the reward and the location of the cue. When monkeys fixated on a cue that signaled the size of future reward, the frequency of microsaccades was higher if the monkey expected a large vs. a small reward. When the cue was presented at a site in the visual field that was remote from the position of fixation, reward size had the opposite effect: the frequency of microsaccades was lower when the monkey was expecting a large reward. The strength of pursuit initiation also was affected by reward size and by the presence of microsaccades just before the onset of target motion. The gain of pursuit initiation increased with reward size and decreased when microsaccades occurred just before or after the onset of target motion. The effect of the reward size on pursuit initiation was much larger than any indirect effects reward might cause through modulation of the rate of microsaccades. We found only a weak relationship between microsaccade direction and the location of the exogenous cue relative to fixation position, even in experiments where the location of the cue indicated the direction of target motion. Our results indicate that the expectation of reward is a powerful modulator of the occurrence of microsaccades, perhaps through attentional mechanisms. Copyright © 2015 the American Physiological Society.

  17. The cellular growth rate controls overall mRNA turnover, and modulates either transcription or degradation rates of particular gene regulons

    PubMed Central

    García-Martínez, José; Delgado-Ramos, Lidia; Ayala, Guillermo; Pelechano, Vicent; Medina, Daniel A.; Carrasco, Fany; González, Ramón; Andrés-León, Eduardo; Steinmetz, Lars; Warringer, Jonas; Chávez, Sebastián; Pérez-Ortín, José E.

    2016-01-01

    We analyzed 80 different genomic experiments, and found a positive correlation between both RNA polymerase II transcription and mRNA degradation with growth rates in yeast. Thus, in spite of the marked variation in mRNA turnover, the total mRNA concentration remained approximately constant. Some genes, however, regulated their mRNA concentration by uncoupling mRNA stability from the transcription rate. Ribosome-related genes modulated their transcription rates to increase mRNA levels under fast growth. In contrast, mitochondria-related and stress-induced genes lowered mRNA levels by reducing mRNA stability or the transcription rate, respectively. We also detected these regulations within the heterogeneity of a wild-type cell population growing in optimal conditions. The transcriptomic analysis of sorted microcolonies confirmed that the growth rate dictates alternative expression programs by modulating transcription and mRNA decay. The regulation of overall mRNA turnover keeps a constant ratio between mRNA decay and the dilution of [mRNA] caused by cellular growth. This regulation minimizes the indiscriminate transmission of mRNAs from mother to daughter cells, and favors the response capacity of the latter to physiological signals and environmental changes. We also conclude that, by uncoupling mRNA synthesis from decay, cells control the mRNA abundance of those gene regulons that characterize fast and slow growth. PMID:26717982

  18. The cellular growth rate controls overall mRNA turnover, and modulates either transcription or degradation rates of particular gene regulons.

    PubMed

    García-Martínez, José; Delgado-Ramos, Lidia; Ayala, Guillermo; Pelechano, Vicent; Medina, Daniel A; Carrasco, Fany; González, Ramón; Andrés-León, Eduardo; Steinmetz, Lars; Warringer, Jonas; Chávez, Sebastián; Pérez-Ortín, José E

    2016-05-05

    We analyzed 80 different genomic experiments, and found a positive correlation between both RNA polymerase II transcription and mRNA degradation with growth rates in yeast. Thus, in spite of the marked variation in mRNA turnover, the total mRNA concentration remained approximately constant. Some genes, however, regulated their mRNA concentration by uncoupling mRNA stability from the transcription rate. Ribosome-related genes modulated their transcription rates to increase mRNA levels under fast growth. In contrast, mitochondria-related and stress-induced genes lowered mRNA levels by reducing mRNA stability or the transcription rate, respectively. We also detected these regulations within the heterogeneity of a wild-type cell population growing in optimal conditions. The transcriptomic analysis of sorted microcolonies confirmed that the growth rate dictates alternative expression programs by modulating transcription and mRNA decay.The regulation of overall mRNA turnover keeps a constant ratio between mRNA decay and the dilution of [mRNA] caused by cellular growth. This regulation minimizes the indiscriminate transmission of mRNAs from mother to daughter cells, and favors the response capacity of the latter to physiological signals and environmental changes. We also conclude that, by uncoupling mRNA synthesis from decay, cells control the mRNA abundance of those gene regulons that characterize fast and slow growth.

  19. Study of new modulation data-transmission formats for dispersion-controlled high-bit-rate fibreoptic communication lines

    SciTech Connect

    Shtyrina, O V; Fedoruk, M P; Turitsyn, S K

    2007-09-30

    The results of simulation of the propagation of optical signals in a multichannel high-bit-rate fibreoptic communication line with a combined scheme for amplifying optical signals based on new modulation data-transmission formats are presented. A comparative characteristic of formats with the amplitude and phase modulations of the electromagnetic-wave carrier is presented. The results of numerical simulation show that phase-modulation formats have a considerable advantage over amplitude formats. The use of phase-modulation formats leads to an increase in the maximum range of high-quality communications by a factor of three on average compared to amplitude-modulation formats. It is shown that optimal propagation regimes both in the case of amplitude-modulation and phase-modulation formats are realised for the normal (negative) group-velocity dispersion. However, the dispersion value for amplitude-modulation formats proves to be considerably greater than for phase-modulation formats. (optical communication)

  20. Frequency shift keying by current modulation in a MTJ-based STNO with high data rate

    NASA Astrophysics Data System (ADS)

    Ruiz-Calaforra, A.; Purbawati, A.; Brächer, T.; Hem, J.; Murapaka, C.; Jiménez, E.; Mauri, D.; Zeltser, A.; Katine, J. A.; Cyrille, M.-C.; Buda-Prejbeanu, L. D.; Ebels, U.

    2017-08-01

    Spin torque nano-oscillators are nanoscopic microwave frequency generators which excel due to their large frequency tuning range and agility for amplitude and frequency modulation. Due to their compactness, they are regarded as suitable candidates for applications in wireless communications, where cost-effective and complementary metal-oxide semiconductor-compatible standalone devices are required. In this work, we study the ability of a magnetic-tunnel-junction based spin torque nano-oscillator to respond to a binary input sequence encoded in a square-shaped current pulse for its application as a frequency-shift-keying (FSK) based emitter. We demonstrate that below the limit imposed by the spin torque nano-oscillator intrinsic relaxation frequency, an agile variation between discrete oscillator states is possible. For this kind of devices, we demonstrate FSK up to data rates of 400 Mbps, which is well suited for the application of such oscillators in wireless networks.

  1. Heart rate response and parasympathetic modulation during recovery from exercise in boys and men.

    PubMed

    Guilkey, Justin P; Overstreet, Matthew; Fernhall, Bo; Mahon, Anthony D

    2014-08-01

    The purpose of this study was to examine the influence of postexercise parasympathetic modulation, measured by heart rate variability (HRV), on heart rate recovery (HRR) in boys (n = 13, 10.1 ± 0.8 years) and men (n = 13, 23.9 ± 1.5 years) following maximal and submaximal exercise. Subjects completed 10 min of supine rest, followed by graded exercise on a cycle ergometer to maximal effort. On a separate day, subjects exercised at an intensity equivalent to ventilatory threshold. Immediately following both exercise bouts, 1-min HRR was assessed in the supine position. HRV was analyzed under controlled breathing during the final 5 min of rest and recovery in the time and frequency domains and transformed to natural log (ln) values. Boys had a greater 1-min HRR than men following maximal (58 ± 8 vs. 47 ± 11 beats·min(-1)) and submaximal (59 ± 8 vs. 47 ± 15 beats·min(-1)) exercise (p < 0.05). Following maximal exercise, boys had greater ln root mean square successive differences in R-R intervals (2.52 ± 0.95 ms), ln standard deviation of NN intervals (3.34 ± 0.57 ms), ln high-frequency power (4.32 ± 2.00 ms(2)), and ln low-frequency power (4.98 ± 1.17 ms(2)) than men (1.33 ± 0.37 ms, 2.52 ± 0.24 ms, 1.32 ± 1.06 ms(2) and 2.80 ± 0.74 ms(2), respectively) (p < 0.05). There were no differences in any HRV variables between groups following submaximal exercise (p > 0.05). In conclusion, it appears that greater parasympathetic modulation accounts for greater HRR following maximal exercise in boys versus men. Although submaximal HRR was greater in boys, parasympathetic responses were similar between groups.

  2. A portable respiratory rate estimation system with a passive single-lead electrocardiogram acquisition module.

    PubMed

    Nayan, Nazrul Anuar; Risman, Nur Sabrina; Jaafar, Rosmina

    2016-07-27

    Among vital signs of acutely ill hospital patients, respiratory rate (RR) is a highly accurate predictor of health deterioration. This study proposes a system that consists of a passive and non-invasive single-lead electrocardiogram (ECG) acquisition module and an ECG-derived respiratory (EDR) algorithm in the working prototype of a mobile application. Before estimating RR that produces the EDR rate, ECG signals were evaluated based on the signal quality index (SQI). The SQI algorithm was validated quantitatively using the PhysioNet/Computing in Cardiology Challenge 2011 training data set. The RR extraction algorithm was validated by adopting 40 MIT PhysioNet Multiparameter Intelligent Monitoring in Intensive Care II data set. The estimated RR showed a mean absolute error (MAE) of 1.4 compared with the ``gold standard'' RR. The proposed system was used to record 20 ECGs of healthy subjects and obtained the estimated RR with MAE of 0.7 bpm. Results indicate that the proposed hardware and algorithm could replace the manual counting method, uncomfortable nasal airflow sensor, chest band, and impedance pneumotachography often used in hospitals. The system also takes advantage of the prevalence of smartphone usage and increase the monitoring frequency of the current ECG of patients with critical illnesses.

  3. Theta, beta and gamma rate modulations in the developing auditory system.

    PubMed

    Vanvooren, Sophie; Hofmann, Michael; Poelmans, Hanne; Ghesquière, Pol; Wouters, Jan

    2015-09-01

    In the brain, the temporal analysis of many important auditory features relies on the synchronized firing of neurons to the auditory input rhythm. These so-called neural oscillations play a crucial role in sensory and cognitive processing and deviances in oscillatory activity have shown to be associated with neurodevelopmental disorders. Given the importance of neural auditory oscillations in normal and impaired sensory and cognitive functioning, there has been growing interest in their developmental trajectory from early childhood on. In the present study, neural auditory processing was investigated in typically developing young children (n = 40) and adults (n = 27). In all participants, auditory evoked theta, beta and gamma responses were recorded. The results of this study show maturational differences between children and adults in neural auditory processing at cortical as well as at brainstem level. Neural background noise at cortical level was shown to be higher in children compared to adults. In addition, higher theta response amplitudes were measured in children compared to adults. For beta and gamma rate modulations, different processing asymmetry patterns were observed between both age groups. The mean response phase was also shown to differ significantly between children and adults for all rates. Results suggest that cortical auditory processing of beta develops from a general processing pattern into a more specialized asymmetric processing preference over age. Moreover, the results indicate an enhancement of bilateral representation of monaural sound input at brainstem with age. A dissimilar efficiency of auditory signal transmission from brainstem to cortex along the auditory pathway between children and adults is suggested. These developmental differences might be due to both functional experience-dependent as well as anatomical changes. The findings of the present study offer important information about maturational differences between children

  4. Brain Correlates of Autonomic Modulation: Combining Heart Rate Variability with fMRI

    PubMed Central

    Napadow, Vitaly; Dhond, Rupali; Conti, Giulia; Makris, Nikos; Brown, Emery N.; Barbieri, Riccardo

    2008-01-01

    The central autonomic network (CAN) has been described in animal models but has been difficult to elucidate in humans. Potential confounds include physiological noise artifacts affecting brainstem neuroimaging data, and difficulty in deriving non-invasive continuous assessments of autonomic modulation. We have developed and implemented a new method which relates cardiac-gated fMRI timeseries with continuous-time heart rate variability (HRV) to estimate central autonomic processing. As many autonomic structures of interest are in brain regions strongly affected by cardiogenic pulsatility, we chose to cardiac-gate our fMRI acquisition to increase sensitivity. Cardiac-gating introduces T1-variability, which was corrected by transforming fMRI data to a fixed TR using a previously published method (Guimaraes et al. 1998). The electrocardiogram was analyzed with a novel point process adaptive-filter algorithm for computation of the high-frequency (HF) index, reflecting the time-varying dynamics of efferent cardiovagal modulation. Central command of cardiovagal outflow was inferred by using the HF timeseries resampled at as a regressor to the fMRI data. A grip task was used to perturb the autonomic nervous system. Our combined HRV-fMRI approach demonstrated HF correlation with fMRI activity in the hypothalamus, cerebellum, parabrachial nucleus/locus ceruleus, periaqueductal gray, amygdala, hippocampus, thalamus, and dorsomedial/dorsolateral prefrontal, posterior insular, and middle temporal cortices. While some regions consistent with central cardiovagal control in animal models gave corroborative evidence for our methodology, other mostly higher cortical or limbic-related brain regions may be unique to humans. Our approach should be optimized and applied to study the human brain correlates of autonomic modulation for various stimuli in both physiological and pathological states. PMID:18524629

  5. 7x 40 Gb/s base-rate RZ all-optical broadcasting utilizing an electroabsorption modulator.

    PubMed

    Xu, L; Chi, N; Yvind, K; Christiansen, L; Oxenløwe, L; Mørk, J; Jeppesen, P; Hanberg, J

    2004-02-09

    We experimentally demonstrate all-optical broadcasting through simultaneous 7 x 40 Gb/s base-rate wavelength conversion in RZ format based on cross absorption modulation in an electroabsorption modulator. In this experiment the original intensity-modulated information is successfully duplicated onto seven wavelengths that comply with the ITU-T proposal. The advantages of the proposed wavelength conversion scheme are also discussed.

  6. Performance evaluations of hybrid modulation with different optical labels over PDQ in high bit-rate OLS network systems.

    PubMed

    Xu, M; Li, Y; Kang, T Z; Zhang, T S; Ji, J H; Yang, S W

    2016-11-14

    Two orthogonal modulation optical label switching(OLS) schemes, which are based on payload of polarization multiplexing-differential quadrature phase shift keying(POLMUX-DQPSK or PDQ) modulated with identifications of duobinary (DB) label and pulse position modulation(PPM) label, are researched in high bit-rate OLS network. The BER performance of hybrid modulation with payload and label signals are discussed and evaluated in theory and simulation. The theoretical BER expressions of PDQ, PDQ-DB and PDQ-PPM are given with analysis method of hybrid modulation encoding in different the bit-rate ratios of payload and label. Theoretical derivation results are shown that the payload of hybrid modulation has a certain gain of receiver sensitivity than payload without label. The sizes of payload BER gain obtained from hybrid modulation are related to the different types of label. The simulation results are consistent with that of theoretical conclusions. The extinction ratio (ER) conflicting between hybrid encoding of intensity and phase types can be compromised and optimized in OLS system of hybrid modulation. The BER analysis method of hybrid modulation encoding in OLS system can be applied to other n-ary hybrid modulation or combination modulation systems.

  7. Brain stimulation modulates the autonomic nervous system, rating of perceived exertion and performance during maximal exercise.

    PubMed

    Okano, Alexandre Hideki; Fontes, Eduardo Bodnariuc; Montenegro, Rafael Ayres; Farinatti, Paulo de Tarso Veras; Cyrino, Edilson Serpeloni; Li, Li Min; Bikson, Marom; Noakes, Timothy David

    2015-09-01

    The temporal and insular cortex (TC, IC) have been associated with autonomic nervous system (ANS) control and the awareness of emotional feelings from the body. Evidence shows that the ANS and rating of perceived exertion (RPE) regulate exercise performance. Non-invasive brain stimulation can modulate the cortical area directly beneath the electrode related to ANS and RPE, but it could also affect subcortical areas by connection within the cortico-cortical neural networks. This study evaluated the effects of transcranial direct current stimulation (tDCS) over the TC on the ANS, RPE and performance during a maximal dynamic exercise. Ten trained cyclists participated in this study (33±9 years; 171.5±5.8 cm; 72.8±9.5 kg; 10-11 training years). After 20-min of receiving either anodal tDCS applied over the left TC (T3) or sham stimulation, subjects completed a maximal incremental cycling exercise test. RPE, heart rate (HR) and R-R intervals (as a measure of ANS function) were recorded continuously throughout the tests. Peak power output (PPO) was recorded at the end of the tests. With anodal tDCS, PPO improved by ~4% (anodal tDCS: 313.2±29.9 vs 301.0±19.8 watts: sham tDCS; p=0.043), parasympathetic vagal withdrawal was delayed (anodal tDCS: 147.5±53.3 vs 125.0±35.4 watts: sham tDCS; p=0.041) and HR was reduced at submaximal workloads. RPE also increased more slowly during exercise following anodal tDCS application, but maximal RPE and HR values were not affected by cortical stimulation. The findings suggest that non-invasive brain stimulation over the TC modulates the ANS activity and the sensory perception of effort and exercise performance, indicating that the brain plays a crucial role in the exercise performance regulation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  8. Disease-Control Rates Following Intensity-Modulated Radiation Therapy for Small Primary Oropharyngeal Carcinoma

    PubMed Central

    Garden, Adam S.; Morrison, William H.; Wong, Pei-Fong; Tung, Sam S.; Rosenthal, David I.; Dong, Lei; Mason, Brian; Perkins, George H.; Ang, K. Kian

    2014-01-01

    Background The purpose of this study was to assess the ability of intensity-modulated radiation therapy (IMRT) to achieve favorable disease-control rates while minimizing parotid gland doses in patients treated for small primary tumors of the oropharynx. Methods We retrospectively identified all patients who received IMRT as treatment for a small (< 4 cm) primary tumor of the oropharynx from October 2000 through June 2002. Tumor characteristics, IMRT parameters, and patient outcomes were assessed. Results Fifty-one patients met the criteria for our study. All patients had treatment to gross disease with margin (CTV1), and all but 1 had treatment to the bilateral necks. The most common treatment schedule (39 patients) was a once-daily fractionation of prescribed doses of 63 - 66 Gy to the CTV1 and 54 Gy to subclinical sites, delivered in 30 fractions. Twenty-one patients (40%) had gastrostomy tubes placed during therapy; in 4 patients, the tube remained in place for more than 6 months following completion of IMRT. The median follow-up was 45 months. The 2-year actuarial local-regional control, recurrence-free, and overall survival rates were 94%, 88%, and 94%, respectively. Conclusions These preliminary data suggest that treatment with IMRT results in favorable local-regional control of small primary oropharynx tumors. IMRT did not appear to have a more favorable acute toxicity profile in this group with respect to the use of a feeding tube; however, the mean dose of radiation delivered to the parotid gland by IMRT was decreased, as 95% of patients had a mean dose of < 30 Gy to at least one gland. PMID:17141972

  9. Disease-control rates following intensity-modulated radiation therapy for small primary oropharyngeal carcinoma

    SciTech Connect

    Garden, Adam S. . E-mail: agarden@mdanderson.org; Morrison, William H.; Wong, P.-F.; Tung, Sam S.; Rosenthal, David I.; Dong Lei; Mason, Brian M.S.; Perkins, George H.; Ang, K. Kian

    2007-02-01

    Background: The purpose of this study was to assess the ability of intensity-modulated radiation therapy (IMRT) to achieve favorable disease-control rates while minimizing parotid gland doses in patients treated for small primary tumors of the oropharynx. Methods and Materials: We retrospectively identified all patients who received IMRT as treatment for a small (<4 cm) primary tumor of the oropharynx between October 2000 and June 2002. Tumor characteristics, IMRT parameters, and patient outcomes were assessed. Results: Fifty-one patients met the criteria for our study. All patients had treatment to gross disease with margin (CTV1), and all but 1 had treatment to the bilateral necks. The most common treatment schedule (39 patients) was a once-daily fractionation of prescribed doses of 63-66 Gy to the CTV1 and 54 Gy to subclinical sites, delivered in 30 fractions. Twenty-one patients (40%) had gastrostomy tubes placed during therapy; in 4 patients, the tube remained in place for more than 6 months after completion of IMRT. The median follow-up was 45 months. The 2-year actuarial locoregional control, recurrence-free, and overall survival rates were 94%, 88%, and 94%, respectively. Conclusions: These preliminary data suggest that treatment with IMRT results in favorable locoregional control of small primary oropharynx tumors. IMRT did not appear to have a more favorable acute toxicity profile in this group with respect to the use of a feeding tube; however, the mean dose of radiation delivered to the parotid gland by IMRT was decreased, because 95% of patients had a mean dose of <30 Gy to at least one gland.

  10. PGR5-PGRL1-Dependent Cyclic Electron Transport Modulates Linear Electron Transport Rate in Arabidopsis thaliana.

    PubMed

    Suorsa, Marjaana; Rossi, Fabio; Tadini, Luca; Labs, Mathias; Colombo, Monica; Jahns, Peter; Kater, Martin M; Leister, Dario; Finazzi, Giovanni; Aro, Eva-Mari; Barbato, Roberto; Pesaresi, Paolo

    2016-02-01

    Plants need tight regulation of photosynthetic electron transport for survival and growth under environmental and metabolic conditions. For this purpose, the linear electron transport (LET) pathway is supplemented by a number of alternative electron transfer pathways and valves. In Arabidopsis, cyclic electron transport (CET) around photosystem I (PSI), which recycles electrons from ferrodoxin to plastoquinone, is the most investigated alternative route. However, the interdependence of LET and CET and the relative importance of CET remain unclear, largely due to the difficulties in precise assessment of the contribution of CET in the presence of LET, which dominates electron flow under physiological conditions. We therefore generated Arabidopsis mutants with a minimal water-splitting activity, and thus a low rate of LET, by combining knockout mutations in PsbO1, PsbP2, PsbQ1, PsbQ2, and PsbR loci. The resulting Δ5 mutant is viable, although mature leaves contain only ∼ 20% of wild-type naturally less abundant PsbO2 protein. Δ5 plants compensate for the reduction in LET by increasing the rate of CET, and inducing a strong non-photochemical quenching (NPQ) response during dark-to-light transitions. To identify the molecular origin of such a high-capacity CET, we constructed three sextuple mutants lacking the qE component of NPQ (Δ5 npq4-1), NDH-mediated CET (Δ5 crr4-3), or PGR5-PGRL1-mediated CET (Δ5 pgr5). Their analysis revealed that PGR5-PGRL1-mediated CET plays a major role in ΔpH formation and induction of NPQ in C3 plants. Moreover, while pgr5 dies at the seedling stage under fluctuating light conditions, Δ5 pgr5 plants are able to survive, which underlines the importance of PGR5 in modulating the intersystem electron transfer.

  11. Dietary protein modulates circadian changes in core body temperature and metabolic rate in rats.

    PubMed

    Yamaoka, Ippei; Nakayama, Mitsuo; Miki, Takanori; Yokoyama, Toshifumi; Takeuchi, Yoshiki

    2008-02-01

    We assessed the contribution of dietary protein to circadian changes in core body temperature (Tb) and metabolic rate in freely moving rats. Daily changes in rat intraperitoneal temperature, locomotor activity (LMA), whole-body oxygen consumption (VO2), and carbon dioxide production (VCO2) were measured before and during 4 days of consuming a 20% protein diet (20% P), a protein-free diet (0% P), or a pair-fed 20% P diet (20% P-R). Changes in Tb did not significantly differ between the 20% P and 20% P-R groups throughout the study. The Tb in the 0% P group remained elevated during the dark (D) phase throughout the study, but VO2, VCO2, and LMA increased late in the study when compared with the 20% P-R group almost in accordance with elevated Tb. By contrast, during the light (L) phase in the 0% P group, Tb became elevated early in the study and thereafter declined with a tendency to accompany significantly lower VO2 and VCO2 when compared with the 20% P group, but not the 20% P-R group. The respiratory quotient (RQ) in the 0% P group declined throughout the D phase and during the early L phase. By contrast, RQ in the 20% P-R group consistently decreased from the late D phase to the end of the L phase. Our findings suggest that dietary protein contributes to the maintenance of daily oscillations in Tb with modulating metabolic rates during the D phase. However, the underlying mechanisms of Tb control during the L phase remain obscure.

  12. Power penalties for multi-level PAM modulation formats at arbitrary bit error rates

    NASA Astrophysics Data System (ADS)

    Kaliteevskiy, Nikolay A.; Wood, William A.; Downie, John D.; Hurley, Jason; Sterlingov, Petr

    2016-03-01

    There is considerable interest in combining multi-level pulsed amplitude modulation formats (PAM-L) and forward error correction (FEC) in next-generation, short-range optical communications links for increased capacity. In this paper we derive new formulas for the optical power penalties due to modulation format complexity relative to PAM-2 and due to inter-symbol interference (ISI). We show that these penalties depend on the required system bit-error rate (BER) and that the conventional formulas overestimate link penalties. Our corrections to the standard formulas are very small at conventional BER levels (typically 1×10-12) but become significant at the higher BER levels enabled by FEC technology, especially for signal distortions due to ISI. The standard formula for format complexity, P = 10log(L-1), is shown to overestimate the actual penalty for PAM-4 and PAM-8 by approximately 0.1 and 0.25 dB respectively at 1×10-3 BER. Then we extend the well-known PAM-2 ISI penalty estimation formula from the IEEE 802.3 standard 10G link modeling spreadsheet to the large BER case and generalize it for arbitrary PAM-L formats. To demonstrate and verify the BER dependence of the ISI penalty, a set of PAM-2 experiments and Monte-Carlo modeling simulations are reported. The experimental results and simulations confirm that the conventional formulas can significantly overestimate ISI penalties at relatively high BER levels. In the experiments, overestimates up to 2 dB are observed at 1×10-3 BER.

  13. Augmented vagal heart rate modulation in active hypoestrogenic pre-menopausal women with functional hypothalamic amenorrhoea.

    PubMed

    O'Donnell, Emma; Goodman, Jack M; Morris, Beverly L; Floras, John S; Harvey, Paula J

    2015-11-01

    Compared with eumenorrhoeic women, exercise-trained women with functional hypothalamic amenorrhoea (ExFHA) exhibit low heart rates (HRs) and absent reflex renin-angiotensin-system activation and augmentation of their muscle sympathetic nerve response to orthostatic stress. To test the hypothesis that their autonomic HR modulation is altered concurrently, three age-matched (pooled mean, 24 ± 1 years; mean ± S.E.M.) groups of women were studied: active with either FHA (ExFHA; n=11) or eumenorrhoeic cycles (ExOv; n=17) and sedentary with eumenorrhoeic cycles (SedOv; n=17). Blood pressure (BP), HR and HR variability (HRV) in the frequency domain were determined during both supine rest and graded lower body negative pressure (LBNP; -10, -20 and -40 mmHg). Very low (VLF), low (LF) and high (HF) frequency power spectra (ms(2)) were determined and, owing to skewness, log10-transformed. LF/HF ratio and total power (VLF + LF + HF) were calculated. At baseline, HR and systolic BP (SBP) were lower (P<0.05) and HF and total power were higher (P<0.05) in ExFHA than in eumenorrhoeic women. In all groups, LBNP decreased (P<0.05) SBP, HF and total power and increased (P<0.05) HR and LF/HF ratio. However, HF and total power remained higher (P<0.05) and HR, SBP and LF/HF ratio remained lower (P<0.05) in ExFHA than in eumenorrhoeic women, in whom measures did not differ (P>0.05). At each stage, HR correlated inversely (P<0.05) with HF. In conclusion, ExFHA women demonstrate augmented vagal yet unchanged sympathetic HR modulation, both at rest and during orthostatic stress. Although the role of oestrogen deficiency is unclear, these findings are in contrast with studies reporting decreased HRV in hypoestrogenic post-menopausal women.

  14. Chaos-induced modulation of reliability boosts output firing rate in downstream cortical areas

    NASA Astrophysics Data System (ADS)

    Tiesinga, P. H.

    2004-03-01

    The reproducibility of neural spike train responses to an identical stimulus across different presentations (trials) has been studied extensively. Reliability, the degree of reproducibility of spike trains, was found to depend in part on the amplitude and frequency content of the stimulus [J. Hunter and J. Milton, J. Neurophysiol. 90, 387 (2003)]. The responses across different trials can sometimes be interpreted as the response of an ensemble of similar neurons to a single stimulus presentation. How does the reliability of the activity of neural ensembles affect information transmission between different cortical areas? We studied a model neural system consisting of two ensembles of neurons with Hodgkin-Huxley-type channels. The first ensemble was driven by an injected sinusoidal current that oscillated in the gamma-frequency range (40 Hz) and its output spike trains in turn drove the second ensemble by fast excitatory synaptic potentials with short term depression. We determined the relationship between the reliability of the first ensemble and the response of the second ensemble. In our paradigm the neurons in the first ensemble were initially in a chaotic state with unreliable and imprecise spike trains. The neurons became entrained to the oscillation and responded reliably when the stimulus power was increased by less than 10%. The firing rate of the first ensemble increased by 30%, whereas that of the second ensemble could increase by an order of magnitude. We also determined the response of the second ensemble when its input spike trains, which had non-Poisson statistics, were replaced by an equivalent ensemble of Poisson spike trains. The resulting output spike trains were significantly different from the original response, as assessed by the metric introduced by Victor and Purpura [J. Neurophysiol. 76, 1310 (1996)]. These results are a proof of principle that weak temporal modulations in the power of gamma-frequency oscillations in a given cortical area

  15. A Crack Growth Rate Conversion Module: Theory, Development, User Guide and Examples

    DTIC Science & Technology

    2007-09-01

    crack closure model, such as FASTRAN, CGAP and AFGROW, requires the conversion of crack growth rate versus the nominal stress ...based on plasiticty-induced crack closure model, such as FASTRAN, CGAP and AFGROW, requires the conversion of crack growth rate versus the nominal stress ...intensity range curves to a "single" curve of crack growth rate versus the effective stress intensity range. In order to minimise the error

  16. Diurnal atmosphere-ocean signals in Earth's rotation rate and a possible modulation through ENSO

    NASA Astrophysics Data System (ADS)

    Schindelegger, M.; Salstein, D.; Einšpigel, D.; Mayerhofer, C.

    2017-03-01

    Space geodetic determinations of a 6 μs length-of-day (LOD) anomaly at the diurnal S1 frequency are reconciled with excitation estimates from geophysical fluid models. Preference is given to a hybrid excitation scheme that combines atmospheric torques with oceanic angular momentum (OAM) terms from hydrodynamic forward modeling. A joint inversion of all data sets yields an LOD in-phase and quadrature estimate of (5.91, -0.22) μs, matching space geodetic S1 terms well within their formal uncertainties. Non-harmonic LOD excitations, while less than 30% of the time-averaged rotation rate contribution, are conclusively linked to El Niño-Southern Oscillation (ENSO) as the main perturbation of diurnal cycle characteristics in the troposphere. ENSO modulations of particular relevance are those in OAM, associated with the barotropic ocean response to regional modifications in the diurnal atmospheric pressure wave. The study thus highlights previously unexplored aspects of non-tidal mass-field variability in the Earth system.

  17. Nectar intake rate is modulated by changes in sucking pump activity according to colony starvation in carpenter ants.

    PubMed

    Falibene, Agustina; Josens, Roxana

    2008-05-01

    Dynamics of fluid feeding has been deeply studied in insects. However, the ability to vary the nectar-intake rate depending only on the carbohydrate deprivation has been clearly demonstrated only in Camponotus mus ants. When insect morphometry and fluid properties remain constant, changes in intake rate could only be attributed to variations in sucking pump activity. Previous records of the electrical activity generated during feeding in C. mus have revealed two different signal patterns: the regular (RP, frequencies: 2-5 Hz) and the irregular (IP, frequencies: 7-12 Hz). This work studies the mechanism underlying food intake-rate modulation in ants by analysing whether these patterns are involved. Behaviour and electrical activity generated by ants at different starvation levels were analysed during feeding on sucrose solutions. Ants were able to modulate the intake rate for a variety of sucrose concentrations (10, 40 and 60%w/w). The IP only occurred for 60% of solutions and its presence did not affect the intake rate. However, during the RP generated under the starved state, we found frequencies up to 7.5 Hz. RP frequencies positively correlated with the intake-rate for all sucrose concentrations. Hence, intake-rate modulation according to sugar deprivation is mainly achieved by the ant's ability to vary the pumping frequency.

  18. Integration of variable-rate OWC with OFDM-PON for hybrid optical access based on adaptive envelope modulation

    NASA Astrophysics Data System (ADS)

    Chen, Chen; Zhong, Wen-De; Wu, Dehao

    2016-12-01

    In this paper, we investigate an integrated optical wireless communication (OWC) and orthogonal frequency division multiplexing based passive optical network (OFDM-PON) system for hybrid wired and wireless optical access, based on an adaptive envelope modulation technique. Both the outdoor and indoor wireless communications are considered in the integrated system. The data for wired access is carried by a conventional OFDM signal, while the data for wireless access is carried by an M-ary pulse amplitude modulation (M-PAM) signal which is modulated onto the envelope of a phase-modulated OFDM signal. By adaptively modulating the wireless M-PAM signal onto the envelope of the wired phase-modulated constant envelope OFDM (CE-OFDM) signal, hybrid wired and wireless optical access can be seamlessly integrated and variable-rate optical wireless transmission can also be achieved. Analytical bit-error-rate (BER) expressions are derived for both the CE-OFDM signal with M-PAM overlay and the overlaid unipolar M-PAM signal, which are verified by Monte Carlo simulations. The BER performances of wired access, indoor OWC wireless access and outdoor OWC wireless access are evaluated. Moreover, variable-rate indoor and outdoor optical wireless access based on the adaptive envelope modulation technique is also discussed.

  19. The reversal of the rotational modulation rates of the north and south components of Saturn kilometric radiation near equinox

    NASA Astrophysics Data System (ADS)

    Gurnett, D. A.; Groene, J. B.; Persoon, A. M.; Menietti, J. D.; Ye, S.-Y.; Kurth, W. S.; MacDowall, R. J.; Lecacheux, A.

    2010-12-01

    It has been known for many years that Saturn emits intense radio emissions at kilometer wavelengths and that this radiation is modulated by the rotation of the planet at a rate that varies slowly on time scales of years. Recently it has been shown that the radio emission consists of two components that have different rotational modulation rates, one emitted from the northern auroral region and the other emitted from the southern auroral region. In this paper we show using radio measurements from the Cassini spacecraft that the rotational modulation rates of the northern and southern components reversed near Saturn's recent equinox, which occurred on 11 August 2009. We show that a similar reversal was also observed by the Ulysses spacecraft near the previous equinox, which occurred on 19 November 1995. The solar control implied by these reversals has important implications on how Saturn's rotation is coupled into the magnetosphere.

  20. Heart rate response after emotional picture presentation is modulated by interoceptive awareness.

    PubMed

    Pollatos, Olga; Herbert, Beate M; Matthias, Ellen; Schandry, Rainer

    2007-01-01

    The perception of visceral signals plays a crucial role in many theories of emotions. The present study was designed to investigate the relationship between interoceptive awareness, emotional experience and heart rate responses in an emotional stimulation paradigm. Based on their performance in a heartbeat perception task 38 participants (16 males, 22 females) were classified as subjects with either high (n=19; 8 males) or low interoceptive awareness (n=19; 8 males). 120 pictures (40 pleasant, 40 unpleasant, 40 neutral slides) from the International Affective Picture System served as emotional stimuli. Heart rate changes were recorded during baseline and during slide presentation. After each slide, the subjects had to rate emotional valence and arousal on a 9-point self-report scale. Statistical analyses revealed significantly stronger heart rate responses to pleasant and unpleasant stimuli in subjects with high interoceptive awareness. Furthermore, subjects with high interoceptive awareness rated pleasant and unpleasant slides as significantly more arousing; no differences were found in the emotional valence ratings. Heartbeat perception scores correlated significantly positive with both the mean arousal rating and with the mean heart rate changes. Our results demonstrate a strong relationship between the perception of cardiac signals and the peripheral processing of emotional stimuli.

  1. Improvements on the refresh rate and dynamical properties of a SLM by sequential readout using an acousto-optic modulator

    NASA Astrophysics Data System (ADS)

    Mestre, Michael; Viaris de Lesegno, Bruno; Farcy, René; Pruvost, Laurence; Bourderionnet, Jérôme; Delboulbé, Anne; Loiseaux, Brigitte; Dolfi, Daniel

    2006-08-01

    We demonstrate the use of an acousto-optic modulator to enhance the refresh rate and dynamic properties of a liquid-crystal spatial light modulator (SLM). The useful area of the SLM surface is split in several zones which are addressed separately, and read in a sequence by a steered laser beam. This configuration allows to increase the refresh rate by five orders of magnitude. Furthermore, improvements on the nature of the transition between different holograms are experimentally shown. The advantages of this technique are discussed in the particular context of cold atom manipulation with holographic optical tweezers.

  2. Heart rate recovery and parasympathetic modulation in boys and girls following maximal and submaximal exercise.

    PubMed

    Guilkey, J P; Overstreet, M; Mahon, A D

    2015-10-01

    This study examined heart rate recovery (HRR) and heart rate variability (HRV) following submaximal and maximal exercise in boys (n = 13; 10.1 ± 0.8 years) and girls (n = 12; 10.1 ± 0.7 years). Participants completed 10 min of supine rest followed by a graded exercise test to maximal effort. On a separate day, participants performed submaximal exercise at ventilatory threshold. Immediately following both exercise bouts, 1-min HRR was assessed in the supine position. HRV variables were analyzed under controlled breathing in the time and frequency domains over the final 5 min of rest and recovery. There were no significant differences in HRR following maximal and submaximal exercise between boys (58 ± 8 and 59 ± 8 beats min(-1), respectively) and girls (54 ± 6 and 52 ± 19 beats min(-1), respectively). There also were no significant interactions between groups from rest to recovery from maximal exercise for any HRV variables. However, there was a difference in the response between sexes from rest to recovery from submaximal exercise for log transformed standard deviation of NN intervals (lnSDNN) and log transformed total power (lnTP). No differences were observed for lnSDNN at rest (boys = 4.61 ± 0.28 vs. girls = 4.28 ± 0.52 ms) or during recovery (lnSDNN: boys 3.78 ± 0.46 vs. girls 3.87 ± 0.64 ms and lnTP: boys 7.33 ± 1.09 vs. girls; 7.44 ± 1.24 ms(2)). Post hoc pairwise comparisons showed a significant difference between boys and girls for lnTP at rest (boys = 9.14 ± 0.42 vs. girls = 8.30 ± 1.05 ms(2)). Parasympathetic modulation was similar between boys and girls at rest and during recovery from exercise, which could explain similarities observed in HRR.

  3. The Role of α7 Nicotinic Acetylcholine Receptor in Modulation of Heart Rate Dynamics in Endotoxemic Rats

    PubMed Central

    Mazloom, Roham; Eftekhari, Golnar; Rahimi, Maryam; Khori, Vahid; Hajizadeh, Sohrab; Dehpour, Ahmad R.; Mani, Ali R.

    2013-01-01

    Previous reports have indicated that artificial stimulation of the vagus nerve reduces systemic inflammation in experimental models of sepsis. This phenomenon is a part of a broader cholinergic anti-inflammatory pathway which activates the vagus nerve to modulate inflammation through activation of alpha7 nicotinic acetylcholine receptors (α7nACHR). Heart rate variability represents the complex interplay between autonomic nervous system and cardiac pacemaker cells. Reduced heart rate variability and increased cardiac cycle regularity is a hallmark of clinical conditions that are associated with systemic inflammation (e.g. endotoxemia and sepsis). The present study was aimed to assess the role of α7nACHR in modulation of heart rate dynamics during systemic inflammation. Systemic inflammation was induced by injection of endotoxin (lipopolysaccharide) in rats. Electrocardiogram and body temperature were recorded in conscious animals using a telemetric system. Linear and non-linear indices of heart rate variability (e.g. sample entropy and fractal-like temporal structure) were assessed. RT-PCR and immunohistochemistry studies showed that α7nACHR is expressed in rat atrium and is mainly localized at the endothelial layer. Systemic administration of an α7nACHR antagonist (methyllycaconitine) did not show a significant effect on body temperature or heart rate dynamics in naïve rats. However, α7nACHR blockade could further reduce heart rate variability and elicit a febrile response in endotoxemic rats. Pre-treatment of endotoxemic animals with an α7nACHR agonist (PHA-543613) was unable to modulate heart rate dynamics in endotoxemic rats but could prevent the effect of endotoxin on body temperature within 24 h experiment. Neither methyllycaconitine nor PHA-543613 could affect cardiac beating variability of isolated perfused hearts taken from control or endotoxemic rats. Based on our observations we suggest a tonic role for nicotinic acetylcholine receptors in

  4. Reconfigurable digital coherent receiver for metro-access networks supporting mixed modulation formats and bit-rates

    NASA Astrophysics Data System (ADS)

    Caballero, Antonio; Gonzalez, Neil Guerrero; Arlunno, Valeria; Borkowski, Robert; Pham, Tien Thang; Rodes, Roberto; Zhang, Xu; Othman, Maisara Binti; Prince, Kamau; Yu, Xianbin; Jensen, Jesper Bevensee; Zibar, Darko; Monroy, Idelfonso Tafur

    2013-12-01

    A single, reconfigurable, digital coherent receiver is proposed and experimentally demonstrated for converged wireless and optical fiber transport. The capacity of reconstructing the full transmitted optical field allows for the demodulation of mixed modulation formats and bit-rates. We performed experimental validation of different modulation formats, including VCSEL based OOK, baseband QPSK, RoF OFDM and wireless IR-UWB over a 78 km deployed fiber link.

  5. Effects of low-intensity exercise conditioning on blood pressure, heart rate, and autonomic modulation of heart rate in men and women with hypertension.

    PubMed

    Hua, Lien P T; Brown, C Ann; Hains, Sylvia J M; Godwin, Marshall; Parlow, Joel L

    2009-10-01

    Untreated hypertension increases cardiovascular risk 2-fold to 3-fold, leading to serious cardiovascular problems that include left ventricular hypertrophy, stroke, ischemic heart disease, myocardial infarction, vascular disease, renal disease, and death. Exercise conditioning is recommended as one of the initial treatments for hypertension. The purpose of this pretest-posttest study was to quantify the effects of a 12-week home-based low-intensity exercise conditioning (walking) program in hypertensive men and women on systolic and diastolic blood pressure, heart rate, and autonomic modulation of heart rate. A total of 20 mildly hypertensive men and women who were assigned to a structured exercise (walking) program were compared with a control group of 20 nonexercising mildly hypertensive participants. Electrocardiographic heart rate and R-R interval data and beat-by-beat arterial blood pressure data were collected continuously for 10 min with participants in the supine and standing postures and during low-intensity steady-state exercise. The results show that systolic and diastolic blood pressure and R-R interval decreased and spontaneous baroreflex sensitivity increased in the exercise group. The decline in blood pressure was significant statistically and clinically. The increase in spontaneous baroreflex sensitivity indicates that the ability of the cardiovascular system to respond rapidly to changing stimuli improved after the 12-week walking protocol. The low-intensity exercise conditioning program achieved a training effect in this population.

  6. Modulation of GDP-fucose level for generating proteins with reduced rate of fucosylation (WO2010141855).

    PubMed

    Taupin, Philippe

    2011-09-01

    The application (WO2010141855) is in the field of glycobiology, and involves the control of the rate of fucosylation of proteins by exogenous factors. It aims at controlling the rate of protein fucosylation with inhibitors (drugs or nucleic acid antagonists) of enzymes involved in the synthesis of GDP-fucose. Mammalian cell lines were cultured in the presence of inhibitors, for example, siRNA. The rates of GDP-fucose in cells and during protein fucosylation were characterized. The level of protein fucosylation decreases rapidly in response to a decrease in GDP-fucose level. The relationship between the rate of fucosylation of proteins and the level of GDP-fucose in a cell is non-linear. Reduction in the rate of protein fucosylation can be achieved with a minimal reduction of the level of GDP-fucose in cells. The paradigm may be used to synthesize proteins and antibodies, with a reduced rate of fucosylation. The application claims that the use of drugs or nucleic acid antagonists that inhibit the enzymes involved in GDP-fucose biosynthesis optimizes the level of GDP-fucose present in cells, and reduces the rate of fucosylation of glycoproteins.

  7. Modulation of post-movement beta rebound by contraction force and rate of force development.

    PubMed

    Fry, Adam; Mullinger, Karen J; O'Neill, George C; Barratt, Eleanor L; Morris, Peter G; Bauer, Markus; Folland, Jonathan P; Brookes, Matthew J

    2016-07-01

    Movement induced modulation of the beta rhythm is one of the most robust neural oscillatory phenomena in the brain. In the preparation and execution phases of movement, a loss in beta amplitude is observed [movement related beta decrease (MRBD)]. This is followed by a rebound above baseline on movement cessation [post movement beta rebound (PMBR)]. These effects have been measured widely, and recent work suggests that they may have significant importance. Specifically, they have potential to form the basis of biomarkers for disease, and have been used in neuroscience applications ranging from brain computer interfaces to markers of neural plasticity. However, despite the robust nature of both MRBD and PMBR, the phenomena themselves are poorly understood. In this study, we characterise MRBD and PMBR during a carefully controlled isometric wrist flexion paradigm, isolating two fundamental movement parameters; force output, and the rate of force development (RFD). Our results show that neither altered force output nor RFD has a significant effect on MRBD. In contrast, PMBR was altered by both parameters. Higher force output results in greater PMBR amplitude, and greater RFD results in a PMBR which is higher in amplitude and shorter in duration. These findings demonstrate that careful control of movement parameters can systematically change PMBR. Further, for temporally protracted movements, the PMBR can be over 7 s in duration. This means accurate control of movement and judicious selection of paradigm parameters are critical in future clinical and basic neuroscientific studies of sensorimotor beta oscillations. Hum Brain Mapp 37:2493-2511, 2016. © 2016 Wiley Periodicals, Inc.

  8. Associations of Heart Rate With Inflammatory Markers Are Modulated by Gender and Obesity in Older Adults

    PubMed Central

    Bandinelli, Stefania; Gemma, Antonella; Ferrucci, Luigi; Incalzi, Raffaele Antonelli

    2015-01-01

    Background. Faster resting heart rate (HR), which is associated with inflammation and elevated cortisol levels, is a risk factor for excess cardiovascular morbidity and mortality. Obesity is associated with increased cardiovascular morbidity and mortality, inflammation, and elevated cortisol levels. The aim of the present study was to evaluate the interaction of Body Mass Index (BMI) with inflammation and cortisol in modulating HR in older subjects. Methods. We analyzed data of 895 participants aged 65+ enrolled in the “InCHIANTI” study, in sinus rhythm, and not taking beta blockers or digoxin. Linear regression was performed to assess the adjusted association between HR, IL-6, and cortisol levels. The model was also analyzed stratifying for BMI tertiles. Logistic regression was adopted for evaluating the association of HR exceeding the mean value with Il-6 and serum cortisol. Results. According to multivariable linear regression, IL-6 and cortisol levels were associated with HR (B = 1.42, 95% CI = 0.43–2.42; p = .005 and B = .34, 95% CI = 0.17–.51; p < .0001, respectively). The association was significant only among women in the highest BMI tertile (B = 4.16, 95% CI = 1.40–6.91; p = .003 for IL-6 and B = .57, 95% CI = 0.14–1.01; p = .010 for cortisol). Logistic regression confirmed that IL-6 and cortisol levels were associated with HR above the mean value in the highest BMI tertile (OR = 2.13, 95% CI = 1.15–3.97; p = .009 and OR = 1.14, 95% CI = 1.03–1.25; p = .009, respectively). Conclusions. Faster HR is associated with proinflammatory state in elderly patients; this association seems to be limited to women with higher BMI. PMID:25429009

  9. Heart rate modulates the slow enhancement of contraction due to sudden left ventricular dilation.

    PubMed

    Tucci, P J; Murad, N; Rossi, C L; Nogueira, R J; Santana, O

    2001-05-01

    In isovolumic blood-perfused dog hearts, left ventricular developed pressure (DP) was recorded while a sudden ventricular dilation was promoted at three heart rate (HR) levels: low (L: 52 +/- 1.7 beats/min), intermediate (M: 82 +/- 2.2 beats/min), and high (H: 117 +/- 3.5 beats/min). DP increased instantaneously with chamber expansion (Delta(1)DP), and another continuous increase occurred for several minutes (Delta(2)DP). HR elevation did not alter Delta(1)DP (32.8 +/- 1.6, 33.6 +/- 1.5, and 34.3 +/- 1.2 mmHg for L, M, and H, respectively), even though it intensified Delta(2)DP (17.3 +/- 0.9, 20.7 +/- 1.0, and 26.8 +/- 1.2 mmHg for L, M, and H, respectively), meaning that the treppe phenomenon enhances the length dependence of the contraction component related to changes in intracellular Ca(2+) concentration. Frequency increments reduced the half time of the slow response (82 +/- 3.6, 67 +/- 2.6, and 53 +/- 2.0 s for L, M, and H, respectively), while the number of beats included in half time increased (72 +/- 2.9, 95 +/- 2.9, and 111 +/- 3.2 beats for L, M, and H, respectively). HR modulation of the slow response suggests that L-type Ca(2+) channel currents and/or the Na(+)/Ca(2+) exchanger plays a relevant role in the stretch-triggered Ca(2+) gain when HR increases in the canine heart.

  10. Associations of Heart Rate With Inflammatory Markers Are Modulated by Gender and Obesity in Older Adults.

    PubMed

    Laudisio, Alice; Bandinelli, Stefania; Gemma, Antonella; Ferrucci, Luigi; Incalzi, Raffaele Antonelli

    2015-07-01

    Faster resting heart rate (HR), which is associated with inflammation and elevated cortisol levels, is a risk factor for excess cardiovascular morbidity and mortality. Obesity is associated with increased cardiovascular morbidity and mortality, inflammation, and elevated cortisol levels. The aim of the present study was to evaluate the interaction of Body Mass Index (BMI) with inflammation and cortisol in modulating HR in older subjects. We analyzed data of 895 participants aged 65+ enrolled in the "InCHIANTI" study, in sinus rhythm, and not taking beta blockers or digoxin. Linear regression was performed to assess the adjusted association between HR, IL-6, and cortisol levels. The model was also analyzed stratifying for BMI tertiles. Logistic regression was adopted for evaluating the association of HR exceeding the mean value with Il-6 and serum cortisol. According to multivariable linear regression, IL-6 and cortisol levels were associated with HR (B = 1.42, 95% CI = 0.43-2.42; p = .005 and B = .34, 95% CI = 0.17-.51; p < .0001, respectively). The association was significant only among women in the highest BMI tertile (B = 4.16, 95% CI = 1.40-6.91; p = .003 for IL-6 and B = .57, 95% CI = 0.14-1.01; p = .010 for cortisol). Logistic regression confirmed that IL-6 and cortisol levels were associated with HR above the mean value in the highest BMI tertile (OR = 2.13, 95% CI = 1.15-3.97; p = .009 and OR = 1.14, 95% CI = 1.03-1.25; p = .009, respectively). Faster HR is associated with proinflammatory state in elderly patients; this association seems to be limited to women with higher BMI. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Modulation of post‐movement beta rebound by contraction force and rate of force development

    PubMed Central

    Fry, Adam; Mullinger, Karen J.; O'Neill, George C.; Barratt, Eleanor L.; Morris, Peter G.; Bauer, Markus; Folland, Jonathan P.

    2016-01-01

    Abstract Movement induced modulation of the beta rhythm is one of the most robust neural oscillatory phenomena in the brain. In the preparation and execution phases of movement, a loss in beta amplitude is observed [movement related beta decrease (MRBD)]. This is followed by a rebound above baseline on movement cessation [post movement beta rebound (PMBR)]. These effects have been measured widely, and recent work suggests that they may have significant importance. Specifically, they have potential to form the basis of biomarkers for disease, and have been used in neuroscience applications ranging from brain computer interfaces to markers of neural plasticity. However, despite the robust nature of both MRBD and PMBR, the phenomena themselves are poorly understood. In this study, we characterise MRBD and PMBR during a carefully controlled isometric wrist flexion paradigm, isolating two fundamental movement parameters; force output, and the rate of force development (RFD). Our results show that neither altered force output nor RFD has a significant effect on MRBD. In contrast, PMBR was altered by both parameters. Higher force output results in greater PMBR amplitude, and greater RFD results in a PMBR which is higher in amplitude and shorter in duration. These findings demonstrate that careful control of movement parameters can systematically change PMBR. Further, for temporally protracted movements, the PMBR can be over 7 s in duration. This means accurate control of movement and judicious selection of paradigm parameters are critical in future clinical and basic neuroscientific studies of sensorimotor beta oscillations. Hum Brain Mapp 37:2493–2511, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc PMID:27061243

  12. Ability of primary auditory cortical neurons to detect amplitude modulation with rate and temporal codes: neurometric analysis

    PubMed Central

    Johnson, Jeffrey S.; Yin, Pingbo; O'Connor, Kevin N.

    2012-01-01

    Amplitude modulation (AM) is a common feature of natural sounds, and its detection is biologically important. Even though most sounds are not fully modulated, the majority of physiological studies have focused on fully modulated (100% modulation depth) sounds. We presented AM noise at a range of modulation depths to awake macaque monkeys while recording from neurons in primary auditory cortex (A1). The ability of neurons to detect partial AM with rate and temporal codes was assessed with signal detection methods. On average, single-cell synchrony was as or more sensitive than spike count in modulation detection. Cells are less sensitive to modulation depth if tested away from their best modulation frequency, particularly for temporal measures. Mean neural modulation detection thresholds in A1 are not as sensitive as behavioral thresholds, but with phase locking the most sensitive neurons are more sensitive, suggesting that for temporal measures the lower-envelope principle cannot account for thresholds. Three methods of preanalysis pooling of spike trains (multiunit, similar to convergence from a cortical column; within cell, similar to convergence of cells with matched response properties; across cell, similar to indiscriminate convergence of cells) all result in an increase in neural sensitivity to modulation depth for both temporal and rate codes. For the across-cell method, pooling of a few dozen cells can result in detection thresholds that approximate those of the behaving animal. With synchrony measures, indiscriminate pooling results in sensitive detection of modulation frequencies between 20 and 60 Hz, suggesting that differences in AM response phase are minor in A1. PMID:22422997

  13. Resting heart rate and risk of sudden cardiac death in the general population: influence of left ventricular systolic dysfunction and heart rate-modulating drugs.

    PubMed

    Teodorescu, Carmen; Reinier, Kyndaron; Uy-Evanado, Audrey; Gunson, Karen; Jui, Jonathan; Chugh, Sumeet S

    2013-08-01

    Higher levels of resting heart rate (HR) have been associated with sudden cardiac death (SCD) but mechanisms are poorly understood. We hypothesized that severe left ventricular systolic dysfunction (LVSD) and HR-modulating drugs explain the HR-SCD relationship. To evaluate the relationship between HR, severe LVSD, HR-modulating drugs, and SCD in the community by using a case-control approach. From the ongoing Oregon Sudden Unexpected Death Study, SCD cases (n = 378) aged ≥35 years and with electrocardiogram-documented resting HR were compared to 378 age- and gender-matched control subjects with coronary artery disease (mean age 68 ± 13 years; 69% man). Associations with SCD were assessed by using multivariable logistic regression. Mean resting HR was significantly higher among SCD cases compared to controls (7.5 beats/min difference; P < .0001). HR was a significant determinant of SCD after adjustment for significant comorbidities and medications (odds ratio for 10 beats/min increase 1.26; 95% confidence interval 1.14-1.38; P < .0001). After considering LVSD, resting HR was slightly attenuated but remained significantly associated with SCD (P = .005). In addition to diabetes and digoxin as well as pulmonary and renal disease, LVSD was also independently associated with SCD (odds ratio 1.79; 95% confidence interval 1.11-2.87; P = .02). Contrary to expectations, the significant relationship between increased resting HR and SCD persisted even after adjustment for LVSD and HR-modulating drugs. These findings suggest a potential role for additional novel interventions/therapies that modulate autonomic tone. Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  14. Biogenic amines modulate pulse rate in the dorsal blood vessel of Lumbriculus variegatus.

    PubMed

    Crisp, Kevin M; Grupe, Rebecca E; Lobsang, Tenzin T; Yang, Xong

    2010-05-01

    The biogenic amines are widespread regulators of physiological processes, and play an important role in regulating heart rate in diverse organisms. Here, we present the first pharmacological evidence for a role of the biogenic amines in the regulation of dorsal blood vessel pulse rate in an aquatic oligochaete, Lumbriculus variegatus (Müller, 1774). Bath application of octopamine to intact worms resulted in an acceleration of pulse rate, but not when co-applied with the adenylyl cyclase inhibitor MDL-12,330a. The phosphodiesterase inhibitor theophylline mimicked the effects of OA, but the polar adenosine receptor antagonist 8(p-sulphophenyl)theophylline was significantly less potent than theophylline. Pharmacologically blocking synaptic reuptake of the biogenic amines using the selective 5-HT reuptake blocker fluoxetine or various tricyclic antidepressants also accelerated heart rate. Depletion of the biogenic amines by treatment with the monoamine vesicular transporter blocker reserpine dramatically depressed pulse rate. Pulse rate was partially restored in amine-depleted worms after treatment with octopamine or dopamine, but fully restored following treatment with serotonin. This effect of 5-HT was weakly mimicked by 5-methoxytryptamine, but not by alpha-methylserotonin; it was completely blocked by clozapine and partially blocked by cyproheptadine. Because they are known to orchestrate a variety of adaptive behaviors in invertebrates, the biogenic amines may coordinate blood flow with behavioral state in L.variegatus.

  15. Modulation of sodium channel gating by external divalent cations: differential effects on opening and closing rates.

    PubMed

    Cukierman, S; Krueger, B K

    1990-06-01

    The effects of external divalent cations on the steady-state open probability (Po), opening and closing rates, and conductance of batrachotoxin (BTX)-activated Na channels were studied in planar lipid bilayers. External divalent cations shifted the midpoint of the Po versus membrane potential (Vm) relation (gating curve) to more depolarized potentials. Of the group IIA divalent cations tested, Ca2+ caused the largest depolarizing shift followed by Ba2+, Sr2+ and Mg2+ in that order. In contrast, the order of decreasing efficacy for block of the single channel conductance was Ca2+, Mg2+, Sr2+ and Ba2+. Thus, because it is a relatively good shifter but a poor blocker, Ba2+ was used to study the effects of divalent cations on gating. External Ba2+ decreased the Na channel opening rate and increased the closing rate. At voltages close to the midpoint of the gating curve, the opening rate decreased by a factor of 1/2.8 while the closing rate increased by 2.0-fold. Although Ba2+ would be expected to increase the external surface potential by interacting with negatively charged residues on the channel, this preferential effect on the opening rate indicates that the effects of external Ba2+ cannot be attributed solely to an increase in the potential gradient across the voltage sensing apparatus.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. In-situ comparison of thermal measurement technologies for interpretation of PV module temperature de-rating effects

    NASA Astrophysics Data System (ADS)

    Elwood, Teri; Bennett, Whit; Lai, Teh; Simmons-Potter, Kelly

    2016-09-01

    It is well known that the efficiency of a photovoltaic (PV) module is strongly impacted by its temperature such that higher temperatures lead to lower energy conversion efficiencies. An accurate measurement of the temperature de-rating effect, therefore, is vital to the correct interpretation of PV module performance under varied environmental conditions. The current work investigates and compares methods for performing measurements of module temperature both in the lab and in field-test environments. A comparison of several temperature measurement devices was made in order to establish the ideal sensor configuration for quantifying module operating temperature. Sensors were also placed in various locations along a string of up to eight photovoltaic modules to examine the variance in operating temperature with position in the string and within a larger array of strings.

  17. A compact 7-cell Si-drift detector module for high-count rate X-ray spectroscopy

    PubMed Central

    Hansen, K.; Reckleben, C.; Diehl, I.; Klär, H.

    2015-01-01

    A new Si-drift detector module for fast X-ray spectroscopy experiments was developed and realized. The Peltier-cooled module comprises a sensor with 7 × 7-mm2 active area, an integrated circuit for amplification, shaping and detection, storage, and derandomized readout of signal pulses in parallel, and amplifiers for line driving. The compactness and hexagonal shape of the module with a wrench size of 16mm allow very short distances to the specimen and multi-module arrangements. The power dissipation is 186mW. At a shaper peaking time of 190 ns and an integration time of 450 ns an electronic rms noise of ~11 electrons was achieved. When operated at 7 °C, FWHM line widths around 260 and 460 eV (Cu-Kα) were obtained at low rates and at sum-count rates of 1.7 MHz, respectively. The peak shift is below 1% for a broad range of count rates. At 1.7-MHz sum-count rate the throughput loss amounts to 30%. PMID:26366028

  18. Utilization of multi-band OFDM modulation to increase traffic rate of phosphor-LED wireless VLC.

    PubMed

    Yeh, Chien-Hung; Chen, Hsing-Yu; Chow, Chi-Wai; Liu, Yen-Liang

    2015-01-26

    To increase the traffic rate in phosphor-LED visible light communication (VLC), a multi-band orthogonal frequency division multiplexed (OFDM) modulation is first proposed and demonstrated. In the measurement, we do not utilize optical blue filter to increase modulation bandwidth of phosphor-LED in the VLC system. In this proposed scheme, different bands of OFDM signals are applied to different LED chips in a LED lamp, this can avoid the power fading and nonlinearity issue by applying the same OFDM signal to all the LED chips in a LED lamp. Here, the maximum increase percentages of traffic rates are 41.1%, 17.8% and 17.8% under received illuminations of 200, 500 and 1000 Lux, respectively, when the proposed three-band OFDM modulation is used in the VLC system. In addition, the analysis and verification by experiments are also performed.

  19. Direction-Modulated Brachytherapy for High-Dose-Rate Treatment of Cervical Cancer. I: Theoretical Design

    SciTech Connect

    Han, Dae Yup; Webster, Matthew J.; Scanderbeg, Daniel J.; Yashar, Catheryn; Choi, Dongju; Song, Bongyong; Devic, Slobodan; Ravi, Ananth; Song, William Y.

    2014-07-01

    Purpose: To demonstrate that utilization of the direction-modulated brachytherapy (DMBT) concept can significantly improve treatment plan quality in the setting of high-dose-rate (HDR) brachytherapy for cervical cancer. Methods and Materials: The new, MRI-compatible, tandem design has 6 peripheral holes of 1.3-mm diameter, grooved along a nonmagnetic tungsten-alloy rod (ρ = 18.0 g/cm{sup 3}), enclosed in Delrin tubing (polyoxymethylene, ρ = 1.41 g/cm{sup 3}), with a total thickness of 6.4 mm. The Monte Carlo N-Particle code was used to calculate the anisotropic {sup 192}Ir dose distributions. An in-house-developed inverse planning platform, geared with simulated annealing and constrained-gradient optimization algorithms, was used to replan 15 patient cases (total 75 plans) treated with a conventional tandem and ovoids (T and O) applicator. Prescription dose was 6 Gy. For replanning, we replaced the conventional tandem with that of the new DMBT tandem for optimization but left the ovoids in place and kept the dwell positions as originally planned. All DMBT plans were normalized to match the high-risk clinical target volume V100 coverage of the T and O plans. Results: In general there were marked improvements in plan quality for the DMBT plans. On average, D2cc for the bladder, rectum, and sigmoid were reduced by 0.59 ± 0.87 Gy (8.5% ± 28.7%), 0.48 ± 0.55 Gy (21.1% ± 27.2%), and 0.10 ± 0.38 Gy (40.6% ± 214.9%) among the 75 plans, with best single-plan reductions of 3.20 Gy (40.8%), 2.38 Gy (40.07%), and 1.26 Gy (27.5%), respectively. The high-risk clinical target volume D90 was similar, with 6.55 ± 0.96 Gy and 6.59 ± 1.06 Gy for T and O and DMBT, respectively. Conclusions: Application of the DMBT concept to cervical cancer allowed for improved organ at risk sparing while achieving similar target coverage on a sizeable patient population, as intended, by maximally utilizing the anatomic information contained in 3-dimensional

  20. Firing rate modulation of human motor units in different muscles during isometric contraction with various forces.

    PubMed

    Seki, K; Narusawa, M

    1996-05-06

    To examine the factors affecting the control of human motor units, rate coding strategies of the motor units were investigated in upper limb and intrinsic hand muscles during voluntary isometric contraction of steady force levels up to 80% of maximal voluntary contraction. Numerous spike trains from single motor units were recorded from the m. first dorsal interosseous (FDI) and the m. biceps brachii (BB) of eight human subjects by means of tungsten micro-electrodes, and the mean firing rate (MFR) was calculated for each subject and inter-individual comparisons made. The MFRs of the FDI were larger than that of the BB at the higher force level, and substantial differences were not found between these muscles at the lower force level. The slope of the linear regression line of MFRs vs. exerted forces for the FDI was more than twice that for the BB. Therefore, isometric force control of the FDI depends more on the rate coding strategy. The difference in rate coding between the FDI and BB motor units may be determined by factors other than muscle fiber composition, because both muscles are known to possess a similar composition of fiber types. Possible mechanisms underlying these characteristics of rate coding strategy are considered in this report.

  1. Ultrasensitive anion detection by NMR spectroscopy: a supramolecular strategy based on modulation of chemical exchange rate.

    PubMed

    Perruchoud, Loïse H; Hadzovic, Alen; Zhang, Xiao-An

    2015-06-08

    NMR spectroscopy is a powerful tool for monitoring molecular interactions and is widely used to characterize supramolecular systems at the atomic level. NMR is limited for sensing purposes, however, due to low sensitivity. Dynamic processes such as conformational changes or binding events can induce drastic effects on NMR spectra in response to variations in chemical exchange (CE) rate, which can lead to new strategies in the design of supramolecular sensors through the control and monitoring of CE rate. Here, we present an indirect NMR anion sensing technique in which increased CE rate, due to anion-induced conformational flexibility of a relatively rigid structure of a novel sensor, allows ultrasensitive anion detection as low as 120 nM.

  2. Generation of tunable, high repetition rate frequency combs with equalized spectra using carrier injection based silicon modulators

    NASA Astrophysics Data System (ADS)

    Nagarjun, K. P.; Selvaraja, Shankar Kumar; Supradeepa, V. R.

    2016-03-01

    High repetition-rate frequency combs with tunable repetition rate and carrier frequency are extensively used in areas like Optical communications, Microwave Photonics and Metrology. A common technique for their generation is strong phase modulation of a CW-laser. This is commonly implemented using Lithium-Niobate based modulators. With phase modulation alone, the combs have poor spectral flatness and significant number of missing lines. To overcome this, a complex cascade of multiple intensity and phase modulators are used. A comb generator on Silicon based on these principles is desirable to enable on-chip integration with other functionalities while reducing power consumption and footprint. In this work, we analyse frequency comb generation in carrier injection based Silicon modulators. We observe an interesting effect in these comb generators. Enhanced absorption accompanying carrier injection, an undesirable effect in data modulators, shapes the amplitude here to enable high quality combs from a single modulator. Thus, along with reduced power consumption to generate a specific number of lines, the complexity has also been significantly reduced. We use a drift-diffusion solver and mode solver (Silvaco TCAD) along with Soref-Bennett relations to calculate the variations in refractive indices and absorption of an optimized Silicon PIN - waveguide modulator driven by an unbiased high frequency (10 Ghz) voltage signal. Our simulations demonstrate that with a device length of 1 cm, a driving voltage of 2V and minor shaping with a passive ring-resonator filter, we obtain 37 lines with a flatness better than 5-dB across the band and power consumption an order of magnitude smaller than Lithium-Niobate modulators.

  3. A dual-input nonlinear system analysis of autonomic modulation of heart rate

    NASA Technical Reports Server (NTRS)

    Chon, K. H.; Mullen, T. J.; Cohen, R. J.

    1996-01-01

    Linear analyses of fluctuations in heart rate and other hemodynamic variables have been used to elucidate cardiovascular regulatory mechanisms. The role of nonlinear contributions to fluctuations in hemodynamic variables has not been fully explored. This paper presents a nonlinear system analysis of the effect of fluctuations in instantaneous lung volume (ILV) and arterial blood pressure (ABP) on heart rate (HR) fluctuations. To successfully employ a nonlinear analysis based on the Laguerre expansion technique (LET), we introduce an efficient procedure for broadening the spectral content of the ILV and ABP inputs to the model by adding white noise. Results from computer simulations demonstrate the effectiveness of broadening the spectral band of input signals to obtain consistent and stable kernel estimates with the use of the LET. Without broadening the band of the ILV and ABP inputs, the LET did not provide stable kernel estimates. Moreover, we extend the LET to the case of multiple inputs in order to accommodate the analysis of the combined effect of ILV and ABP effect on heart rate. Analyzes of data based on the second-order Volterra-Wiener model reveal an important contribution of the second-order kernels to the description of the effect of lung volume and arterial blood pressure on heart rate. Furthermore, physiological effects of the autonomic blocking agents propranolol and atropine on changes in the first- and second-order kernels are also discussed.

  4. Enhancing sensitivity to interaural time differences at high modulation rates by introducing temporal jitter

    PubMed Central

    Goupell, Matthew J.; Laback, Bernhard; Majdak, Piotr

    2009-01-01

    Sensitivity to interaural time differences (ITDs) in high-frequency bandpass-filtered periodic and aperiodic (jittered) pulse trains was tested at a nominal pulse rate of 600 pulses per second (pps). It was found that random binaurally-synchronized jitter of the pulse timing significantly increases ITD sensitivity. A second experiment studied the effects of rate and place. ITD sensitivity for jittered 1200-pps pulse trains was significantly higher than for periodic 600-pps pulse trains, and there was a relatively small effect of place. Furthermore, it could be concluded from this experiment that listeners were not solely benefiting from the longest interpulse intervals (IPIs) and the instances of reduced rate by adding jitter, because the two types of pulse trains had the same longest IPI. The effect of jitter was studied using a physiologically-based model of auditory nerve and brainstem (medial superior olive neurons). It was found that the random timing of the jittered pulses increased firing synchrony in the auditory periphery, which caused an improved rate-ITD tuning for the 600-pps pulse trains. These results suggest that a recovery from binaural adaptation induced by temporal jitter is possibly related to changes in the temporal firing pattern, not spectral changes. PMID:19894831

  5. A dual-input nonlinear system analysis of autonomic modulation of heart rate

    NASA Technical Reports Server (NTRS)

    Chon, K. H.; Mullen, T. J.; Cohen, R. J.

    1996-01-01

    Linear analyses of fluctuations in heart rate and other hemodynamic variables have been used to elucidate cardiovascular regulatory mechanisms. The role of nonlinear contributions to fluctuations in hemodynamic variables has not been fully explored. This paper presents a nonlinear system analysis of the effect of fluctuations in instantaneous lung volume (ILV) and arterial blood pressure (ABP) on heart rate (HR) fluctuations. To successfully employ a nonlinear analysis based on the Laguerre expansion technique (LET), we introduce an efficient procedure for broadening the spectral content of the ILV and ABP inputs to the model by adding white noise. Results from computer simulations demonstrate the effectiveness of broadening the spectral band of input signals to obtain consistent and stable kernel estimates with the use of the LET. Without broadening the band of the ILV and ABP inputs, the LET did not provide stable kernel estimates. Moreover, we extend the LET to the case of multiple inputs in order to accommodate the analysis of the combined effect of ILV and ABP effect on heart rate. Analyzes of data based on the second-order Volterra-Wiener model reveal an important contribution of the second-order kernels to the description of the effect of lung volume and arterial blood pressure on heart rate. Furthermore, physiological effects of the autonomic blocking agents propranolol and atropine on changes in the first- and second-order kernels are also discussed.

  6. A dual-input nonlinear system analysis of autonomic modulation of heart rate.

    PubMed

    Chon, K H; Mullen, T J; Cohen, R J

    1996-05-01

    Linear analyses of fluctuations in heart rate and other hemodynamic variables have been used to elucidate cardiovascular regulatory mechanisms. The role of nonlinear contributions to fluctuations in hemodynamic variables has not been fully explored. This paper presents a nonlinear system analysis of the effect of fluctuations in instantaneous lung volume (ILV) and arterial blood pressure (ABP) on heart rate (HR) fluctuations. To successfully employ a nonlinear analysis based on the Laguerre expansion technique (LET), we introduce an efficient procedure for broadening the spectral content of the ILV and ABP inputs to the model by adding white noise. Results from computer simulations demonstrate the effectiveness of broadening the spectral band of input signals to obtain consistent and stable kernel estimates with the use of the LET. Without broadening the band of the ILV and ABP inputs, the LET did not provide stable kernel estimates. Moreover, we extend the LET to the case of multiple inputs in order to accommodate the analysis of the combined effect of ILV and ABP effect on heart rate. Analyzes of data based on the second-order Volterra-Wiener model reveal an important contribution of the second-order kernels to the description of the effect of lung volume and arterial blood pressure on heart rate. Furthermore, physiological effects of the autonomic blocking agents propranolol and atropine on changes in the first- and second-order kernels are also discussed.

  7. Absence of arterial baroreflex modulation of skin sympathetic activity and sweat rate during whole-body heating in humans

    NASA Technical Reports Server (NTRS)

    Wilson, T. E.; Cui, J.; Crandall, C. G.

    2001-01-01

    1. Prior findings suggest that baroreflexes are capable of modulating skin blood flow, but the effects of baroreceptor loading/unloading on sweating are less clear. Therefore, this project tested the hypothesis that pharmacologically induced alterations in arterial blood pressure in heated humans would lead to baroreflex-mediated changes in both skin sympathetic nerve activity (SSNA) and sweat rate. 2. In seven subjects mean arterial blood pressure was lowered (approximately 8 mmHg) and then raised (approximately 13 mmHg) by bolus injections of sodium nitroprusside and phenylephrine, respectively. Moreover, in a separate protocol, arterial blood pressure was reduced via steady-state administration of sodium nitroprusside. In both normothermia and heat-stress conditions the following responses were monitored: sublingual and mean skin temperatures, heart rate, beat-by-beat blood pressure, skin blood flow (laser-Doppler flowmetry), local sweat rate and SSNA (microneurography from peroneal nerve). 3. Whole-body heating increased skin and sublingual temperatures, heart rate, cutaneous blood flow, sweat rate and SSNA, but did not change arterial blood pressure. Heart rate was significantly elevated (from 74 +/- 3 to 92 +/- 4 beats x min(-1); P < 0.001) during bolus sodium nitroprusside-induced reductions in blood pressure, and significantly reduced (from 92 +/- 4 to 68 +/- 4 beats x min(-1); P < 0.001) during bolus phenylephrine-induced elevations in blood pressure, thereby demonstrating normal baroreflex function in these subjects. 4. Neither SSNA nor sweat rate was altered by rapid (bolus infusion) or sustained (steady-state infusion) changes in blood pressure regardless of the thermal condition. 5. These data suggest that SSNA and sweat rate are not modulated by arterial baroreflexes in normothermic or moderately heated individuals.

  8. Absence of arterial baroreflex modulation of skin sympathetic activity and sweat rate during whole-body heating in humans

    PubMed Central

    Wilson, Thad E; Cui, Jian; Crandall, Craig G

    2001-01-01

    Prior findings suggest that baroreflexes are capable of modulating skin blood flow, but the effects of baroreceptor loading/unloading on sweating are less clear. Therefore, this project tested the hypothesis that pharmacologically induced alterations in arterial blood pressure in heated humans would lead to baroreflex-mediated changes in both skin sympathetic nerve activity (SSNA) and sweat rate. In seven subjects mean arterial blood pressure was lowered (≈8 mmHg) and then raised (≈13 mmHg) by bolus injections of sodium nitroprusside and phenylephrine, respectively. Moreover, in a separate protocol, arterial blood pressure was reduced via steady-state administration of sodium nitroprusside. In both normothermia and heat-stress conditions the following responses were monitored: sublingual and mean skin temperatures, heart rate, beat-by-beat blood pressure, skin blood flow (laser-Doppler flowmetry), local sweat rate and SSNA (microneurography from peroneal nerve). Whole-body heating increased skin and sublingual temperatures, heart rate, cutaneous blood flow, sweat rate and SSNA, but did not change arterial blood pressure. Heart rate was significantly elevated (from 74 ± 3 to 92 ± 4 beats min−1; P < 0.001) during bolus sodium nitroprusside-induced reductions in blood pressure, and significantly reduced (from 92 ± 4 to 68 ± 4 beats min−1; P < 0.001) during bolus phenylephrine-induced elevations in blood pressure, thereby demonstrating normal baroreflex function in these subjects. Neither SSNA nor sweat rate was altered by rapid (bolus infusion) or sustained (steady-state infusion) changes in blood pressure regardless of the thermal condition. These data suggest that SSNA and sweat rate are not modulated by arterial baroreflexes in normothermic or moderately heated individuals. PMID:11600694

  9. Absence of arterial baroreflex modulation of skin sympathetic activity and sweat rate during whole-body heating in humans

    NASA Technical Reports Server (NTRS)

    Wilson, T. E.; Cui, J.; Crandall, C. G.

    2001-01-01

    1. Prior findings suggest that baroreflexes are capable of modulating skin blood flow, but the effects of baroreceptor loading/unloading on sweating are less clear. Therefore, this project tested the hypothesis that pharmacologically induced alterations in arterial blood pressure in heated humans would lead to baroreflex-mediated changes in both skin sympathetic nerve activity (SSNA) and sweat rate. 2. In seven subjects mean arterial blood pressure was lowered (approximately 8 mmHg) and then raised (approximately 13 mmHg) by bolus injections of sodium nitroprusside and phenylephrine, respectively. Moreover, in a separate protocol, arterial blood pressure was reduced via steady-state administration of sodium nitroprusside. In both normothermia and heat-stress conditions the following responses were monitored: sublingual and mean skin temperatures, heart rate, beat-by-beat blood pressure, skin blood flow (laser-Doppler flowmetry), local sweat rate and SSNA (microneurography from peroneal nerve). 3. Whole-body heating increased skin and sublingual temperatures, heart rate, cutaneous blood flow, sweat rate and SSNA, but did not change arterial blood pressure. Heart rate was significantly elevated (from 74 +/- 3 to 92 +/- 4 beats x min(-1); P < 0.001) during bolus sodium nitroprusside-induced reductions in blood pressure, and significantly reduced (from 92 +/- 4 to 68 +/- 4 beats x min(-1); P < 0.001) during bolus phenylephrine-induced elevations in blood pressure, thereby demonstrating normal baroreflex function in these subjects. 4. Neither SSNA nor sweat rate was altered by rapid (bolus infusion) or sustained (steady-state infusion) changes in blood pressure regardless of the thermal condition. 5. These data suggest that SSNA and sweat rate are not modulated by arterial baroreflexes in normothermic or moderately heated individuals.

  10. Hypnosis modulates behavioural measures and subjective ratings about external and internal awareness.

    PubMed

    Demertzi, Athena; Vanhaudenhuyse, Audrey; Noirhomme, Quentin; Faymonville, Marie-Elisabeth; Laureys, Steven

    2015-12-01

    In altered subjective states, the behavioural quantification of external and internal awareness remains challenging due to the need for reports on the subjects' behalf. With the aim to characterize the behavioural counterpart of external and internal awareness in a modified subjective condition, we used hypnosis during which subjects remain fully responsive. Eleven right-handed subjects reached a satisfactory level of hypnotisability as evidenced by subjective reports on arousal, absorption and dissociation. Compared to normal wakefulness, in hypnosis (a) participants' self-ratings for internal awareness increased and self-ratings for external awareness decreased, (b) the two awareness components tended to anticorrelate less and the switches between external and internal awareness self-ratings were less frequent, and (c) participants' reaction times were higher and lapses in key presses were more frequent. The identified imbalance between the two components of awareness is considered as of functional relevance to subjective (meta)cognition, possibly mediated by allocated attentional properties brought about by hypnosis. Our results highlight the presence of a cognitive counterpart in resting state, indicate that the modified contents of awareness are measurable behaviourally, and provide leverage for investigations of more challenging altered conscious states, such as anaesthesia, sleep and disorders of consciousness. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Chromatic dispersion monitoring for multiple modulation formats and data rates using sideband optical filtering and asynchronous amplitude sampling technique.

    PubMed

    Khan, F N; Lau, Alan Pak Tao; Lu, Chao; Wai, P K A

    2011-01-17

    We propose and experimentally demonstrate a low-cost technique for chromatic dispersion (CD) monitoring in various return-to-zero (RZ) amplitude and phase-modulated systems at different data rates by analyzing the asynchronously sampled amplitudes of two vestigial sideband (VSB) signals. The proposed technique graphically represents the CD induced-effects in a scatter plot of which a parameter is extracted to monitor CD and is resilient to OSNR variations. Simulations and experimental results demonstrate good monitoring ranges and sensitivities for various modulation formats at different data rates without any modification of the monitoring hardware. The influence of first-order polarization-mode dispersion (PMD) on the accuracy of proposed monitoring technique is also investigated.

  12. Modulating the rate of charge transport in a metal-organic framework thin film using host:guest chemistry.

    PubMed

    Hod, Idan; Farha, Omar K; Hupp, Joseph T

    2016-01-28

    Herein we demonstrate the use of host-guest chemistry to modulate rates of charge transport in metal-organic framework (MOF) films. The kinetics of site-to-site of charge hopping and, in turn, the overall redox conductivity, of a ferrocene-modified MOF can be altered by up to 30-fold by coupling electron exchange to the oxidation-state-dependent formation of inclusion complexes between cyclodextrin and channel-tethered metallocenes.

  13. Strong modulation of ectopic focus as a mechanism of repetitive interpolated ventricular bigeminy with heart rate doubling.

    PubMed

    Takayanagi, Kan; Nakahara, Shiro; Toratani, Noritaka; Chida, Ryuji; Kobayashi, Sayuki; Sakai, Yoshihiko; Takeuchi, Akihiro; Ikeda, Noriaki

    2013-10-01

    Repetitive interpolated ventricular bigeminy (RIVB) can introduce a doubling of the ventricular rate. To clarify the mechanism of RIVB, we hypothesized that it was introduced by a strong modulation of the ventricular automatic focus. RIVB, defined as more than 7 bigeminy events, was detected by instantaneous heart rate and bigeminy interval (BI) tachograms in 1450 successive patients with frequent ventricular premature contractions (≥3000 per day). Postextrasystolic interval bigeminy interval curves were plotted to determine the degree of modulation. Mean sinus cycle length bigeminy interval curves were plotted for selection. RIVB was simulated by using a computer-based parasystole model. RIVB was observed in 7 patients (age 60 ± 16 years; 2 men and 5 women) with a heart rate of 58.2 ± 6.5 beats/min during a rest period both during the day and at night. The tachograms disclosed the onset of the RIVB with a doubled ventricular rate to 112.3 ± 8.5 beats/min. On the postextrasystolic interval bigeminy interval curves, compensatory bigeminy and interpolated bigeminy constituted overlapping regression lines with slopes close to 1.00 and RIVB was located in the lower left portion. RIVB lasting for up to 3 hours was quickly detected by mean sinus cycle length bigeminy interval curve. The PQ interval immediately after RIVB was prolonged in comparison with baseline (0.18 ± 0.02 to 0.21 ± 0.02 seconds; P < .001). The simulation was able to reproduce RIVB faithfully at a slow heart rate. Our findings support the hypothesis that RIVB was introduced by strongly modulated ventricular pacemaker accelerated by an intervening normal QRS. © 2013 Heart Rhythm Society. All rights reserved.

  14. Low-Complexity, Digital Encoder/Modulator Developed for High-Data-Rate Satellite B-ISDN Applications

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Space Electronics Division at the NASA Lewis Research Center is developing advanced electronic technologies for the space communications and remote sensing systems of tomorrow. As part of the continuing effort to advance the state-of-the-art in satellite communications and remote sensing systems, Lewis developed a low-cost, modular, programmable, and reconfigurable all-digital encoder-modulator (DEM) for medium- to high-data-rate radiofrequency communication links. The DEM is particularly well suited to high-data-rate downlinks to ground terminals or direct data downlinks from near-Earth science platforms. It can support data rates up to 250 megabits per second (Mbps) and several modulation schemes, including the traditional binary phase-shift keying (BPSK) and quadrature phase-shift keying (QPSK) modes, as well as higher order schemes such as 8 phase-shift keying (8PSK) and 16 quadrature amplitude modulation (16QAM). The DEM architecture also can precompensate for channel disturbances and alleviate amplitude degradations caused by nonlinear transponder characteristics.

  15. Feeding ecology informs parasite epidemiology: prey selection modulates encounter rate with Echinococcus multilocularis in urban coyotes.

    PubMed

    Liccioli, Stefano; Bialowas, Carly; Ruckstuhl, Kathreen E; Massolo, Alessandro

    2015-01-01

    We investigated the role of urban coyote feeding ecology in the transmission of Echinococcus multilocularis, the causative agent of Alveolar Echinococcosis in humans. As coyotes can play a main role in the maintenance of this zoonotic parasite within North American urban settings, such study can ultimately aid disease risk management. Between June 2012 and June 2013, we collected 251 coyote feces and conducted trapping of small mammals (n = 971) in five parks in the city of Calgary, Alberta, Canada. We investigated E. multilocularis epidemiology by assessing seasonal variations of coyote diet and the selective consumption of different rodent intermediate host species. Furthermore, accounting for small mammal digestibility and coyote defecation rates we estimated the number of small mammal preys ingested by coyote and consequently, coyote encounter rates with the parasite. Dominant food items included small mammals, fruit and vegetation, although hare and deer were seasonally relevant. The lowest frequency of occurrence per scat of small mammals was recorded in winter (39.4%), when consumption of deer was highest (36.4%). However, highest encounter rates (number of infected hosts predated/season) with E. multilocularis (95% CI: 1.0-22.4), combined with the lack of predation on non-competent small mammal species, suggest that winter is the critical season for transmission and control of this parasite. Within the small mammal assemblage, voles (Microtus pennsylvanicus and Myodes gapperi) were the selected preys of urban coyotes and likely played a key role for the maintenance of the urban sylvatic life-cycle of E. multilocularis in Calgary.

  16. Feeding Ecology Informs Parasite Epidemiology: Prey Selection Modulates Encounter Rate with Echinococcus multilocularis in Urban Coyotes

    PubMed Central

    Liccioli, Stefano; Bialowas, Carly; Ruckstuhl, Kathreen E.; Massolo, Alessandro

    2015-01-01

    We investigated the role of urban coyote feeding ecology in the transmission of Echinococcus multilocularis, the causative agent of Alveolar Echinococcosis in humans. As coyotes can play a main role in the maintenance of this zoonotic parasite within North American urban settings, such study can ultimately aid disease risk management. Between June 2012 and June 2013, we collected 251 coyote feces and conducted trapping of small mammals (n = 971) in five parks in the city of Calgary, Alberta, Canada. We investigated E. multilocularis epidemiology by assessing seasonal variations of coyote diet and the selective consumption of different rodent intermediate host species. Furthermore, accounting for small mammal digestibility and coyote defecation rates we estimated the number of small mammal preys ingested by coyote and consequently, coyote encounter rates with the parasite. Dominant food items included small mammals, fruit and vegetation, although hare and deer were seasonally relevant. The lowest frequency of occurrence per scat of small mammals was recorded in winter (39.4 %), when consumption of deer was highest (36.4 %). However, highest encounter rates (number of infected hosts predated/season) with E. multilocularis (95% CI: 1.0 - 22.4), combined with the lack of predation on non-competent small mammal species, suggest that winter is the critical season for transmission and control of this parasite. Within the small mammal assemblage, voles (Microtus pennsylvanicus and Myodes gapperi) were the selected preys of urban coyotes and likely played a key role for the maintenance of the urban sylvatic life-cycle of E. multilocularis in Calgary. PMID:25768437

  17. Time Modulation of the {beta}{sup +}-Decay Rate of H-Like {sup 140}Pr{sup 58+} Ions

    SciTech Connect

    Ivanov, A. N.; Kryshen, E. L.; Pitschmann, M.; Kienle, P.

    2008-10-31

    Recent experimental data at GSI on the rates of the number of daughter ions, produced by the nuclear K-shell electron capture (EC) decays of the H-like ions {sup 140}Pr{sup 58+} and {sup 142}Pm{sup 60+}, suggest that they are modulated in time with periods T{sub EC}{approx_equal}7 sec and amplitudes a{sub EC}{approx_equal}0.20. Since it is known that these ions are unstable also under the nuclear positron ({beta}{sup +}) decays, we study a possible time dependence of the nuclear {beta}{sup +}-decay rate of the H-like {sup 140}Pr{sup 58+} ion. We show that the time dependence of the {beta}{sup +}-decay rate of the H-like {sup 140}Pr{sup 58+} ion as well as any H-like heavy ions cannot be observed.

  18. Behavior related pauses in simple spike activity of mouse Purkinje cells are linked to spike rate modulation

    PubMed Central

    Cao, Ying; Maran, Selva K.; Dhamala, Mukesh; Jaeger, Dieter; Heck, Detlef H.

    2012-01-01

    Purkinje cells (PCs) in the mammalian cerebellum express high frequency spontaneous activity with average spike rates between 30 and 200 Hz. Cerebellar nuclear (CN) neurons receive converging input from many PCs resulting in a continuous barrage of inhibitory inputs. It has been hypothesized that pauses in PC activity trigger increases in CN spiking activity. A prediction derived from this hypothesis is that pauses in PC simple spike activity represent relevant behavioral or sensory events. Here we asked whether pauses in the simple spike activity of PCs related to either fluid licking or respiration, play a special role in representing information about behavior. Both behaviors are widely represented in cerebellar PC simple spike activity. We recorded PC activity in the vermis and lobus simplex of head fixed mice while monitoring licking and respiratory behavior. Using cross correlation and Granger causality analysis we examined whether short ISIs had a different temporal relation to behavior than long ISIs or pauses. Behavior related simple spike pauses occurred during low-rate simple spike activity in both licking and breathing related PCs. Granger causality analysis revealed causal relationships between simple spike pauses and behavior. However, the same results were obtained from an analysis of surrogate spike trains with gamma ISI distributions constructed to match rate modulations of behavior related Purkinje cells. Our results therefore suggest that the occurrence of pauses in simple spike activity does not represent additional information about behavioral or sensory events that goes beyond the simple spike rate modulations. PMID:22723707

  19. FPGA-based rate-adaptive LDPC-coded modulation for the next generation of optical communication systems.

    PubMed

    Zou, Ding; Djordjevic, Ivan B

    2016-09-05

    In this paper, we propose a rate-adaptive FEC scheme based on LDPC codes together with its software reconfigurable unified FPGA architecture. By FPGA emulation, we demonstrate that the proposed class of rate-adaptive LDPC codes based on shortening with an overhead from 25% to 42.9% provides a coding gain ranging from 13.08 dB to 14.28 dB at a post-FEC BER of 10-15 for BPSK transmission. In addition, the proposed rate-adaptive LDPC coding combined with higher-order modulations have been demonstrated including QPSK, 8-QAM, 16-QAM, 32-QAM, and 64-QAM, which covers a wide range of signal-to-noise ratios. Furthermore, we apply the unequal error protection by employing different LDPC codes on different bits in 16-QAM and 64-QAM, which results in additional 0.5dB gain compared to conventional LDPC coded modulation with the same code rate of corresponding LDPC code.

  20. The FAST module: an add-on unit for driving commercial scanning probe microscopes at video rate and beyond.

    PubMed

    Esch, Friedrich; Dri, Carlo; Spessot, Alessio; Africh, Cristina; Cautero, Giuseppe; Giuressi, Dario; Sergo, Rudi; Tommasini, Riccardo; Comelli, Giovanni

    2011-05-01

    We present the design and the performance of the FAST (Fast Acquisition of SPM Timeseries) module, an add-on instrument that can drive commercial scanning probe microscopes (SPM) at and beyond video rate image frequencies. In the design of this module, we adopted and integrated several technical solutions previously proposed by different groups in order to overcome the problems encountered when driving SPMs at high scanning frequencies. The fast probe motion control and signal acquisition are implemented in a way that is totally transparent to the existing control electronics, allowing the user to switch immediately and seamlessly to the fast scanning mode when imaging in the conventional slow mode. The unit provides a completely non-invasive, fast scanning upgrade to common SPM instruments that are not specifically designed for high speed scanning. To test its performance, we used this module to drive a commercial scanning tunneling microscope (STM) system in a quasi-constant height mode to frame rates of 100 Hz and above, demonstrating extremely stable and high resolution imaging capabilities. The module is extremely versatile and its application is not limited to STM setups but can, in principle, be generalized to any scanning probe instrument.

  1. The FAST module: An add-on unit for driving commercial scanning probe microscopes at video rate and beyond

    NASA Astrophysics Data System (ADS)

    Esch, Friedrich; Dri, Carlo; Spessot, Alessio; Africh, Cristina; Cautero, Giuseppe; Giuressi, Dario; Sergo, Rudi; Tommasini, Riccardo; Comelli, Giovanni

    2011-05-01

    We present the design and the performance of the FAST (Fast Acquisition of SPM Timeseries) module, an add-on instrument that can drive commercial scanning probe microscopes (SPM) at and beyond video rate image frequencies. In the design of this module, we adopted and integrated several technical solutions previously proposed by different groups in order to overcome the problems encountered when driving SPMs at high scanning frequencies. The fast probe motion control and signal acquisition are implemented in a way that is totally transparent to the existing control electronics, allowing the user to switch immediately and seamlessly to the fast scanning mode when imaging in the conventional slow mode. The unit provides a completely non-invasive, fast scanning upgrade to common SPM instruments that are not specifically designed for high speed scanning. To test its performance, we used this module to drive a commercial scanning tunneling microscope (STM) system in a quasi-constant height mode to frame rates of 100 Hz and above, demonstrating extremely stable and high resolution imaging capabilities. The module is extremely versatile and its application is not limited to STM setups but can, in principle, be generalized to any scanning probe instrument.

  2. Method and apparatus for active control of combustion rate through modulation of heat transfer from the combustion chamber wall

    DOEpatents

    Roberts, Jr., Charles E.; Chadwell, Christopher J.

    2004-09-21

    The flame propagation rate resulting from a combustion event in the combustion chamber of an internal combustion engine is controlled by modulation of the heat transfer from the combustion flame to the combustion chamber walls. In one embodiment, heat transfer from the combustion flame to the combustion chamber walls is mechanically modulated by a movable member that is inserted into, or withdrawn from, the combustion chamber thereby changing the shape of the combustion chamber and the combustion chamber wall surface area. In another embodiment, heat transfer from the combustion flame to the combustion chamber walls is modulated by cooling the surface of a portion of the combustion chamber wall that is in close proximity to the area of the combustion chamber where flame speed control is desired.

  3. Amplitude modulation rate dependent topographic organization of the auditory steady-state response in human auditory cortex.

    PubMed

    Weisz, Nathan; Lithari, Chrysoula

    2017-10-01

    Periodic modulations of an acoustic feature, such as amplitude over a certain frequency range, leads to phase locking of neural responses to the envelope of the modulation. Using electrophysiological methods this neural activity pattern, also called the auditory steady-state response (aSSR), is visible following frequency transformation of the evoked response as a clear spectral peak at the modulation frequency. Despite several studies employing the aSSR that show, for example, strongest responses for ∼40 Hz and an overall right-hemispheric dominance, it has not been investigated so far to what extent within auditory cortex different modulation frequencies elicit aSSRs at a homogenous source or whether the localization of the aSSR is topographically organized in a systematic manner. The latter would be suggested by previous neuroimaging works in monkeys and humans showing a periodotopic organization within and across distinct auditory fields. However, the sluggishness of the signal from these neuroimaging works prohibit inferences with regards to the fine-temporal features of the neural response. In the present study, we employed amplitude-modulated (AM) sounds over a range between 4 and 85 Hz to elicit aSSRs while recording brain activity via magnetoencephalography (MEG). Using beamforming and a fine spatially resolved grid restricted to auditory cortical processing regions, our study revealed a topographic representation of the aSSR that depends on AM rate, in particular in the medial-lateral (bilateral) and posterior-anterior (right auditory cortex) direction. In summary, our findings confirm previous studies that showing different AM rates to elicit maximal response in distinct neural populations. They extend these findings however by also showing that these respective neural ensembles in auditory cortex actually phase lock their activity over a wide modulation frequency range. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  4. Analysis of autonomic modulation of heart rate in patients with Parkinson's disease and elderly individuals submitted to game therapy training.

    PubMed

    Rocha, Rodrigo Santiago Barbosa; De Oliveira Rocha, Larissa Salgado; Pena, Elza Sara Maués; Caldas, Laiz Cristinna Ponce; Moreno, Marlene Aparecida

    2017-08-23

    Elderly patients and individuals with Parkinson's disease have a reduction in autonomic heart rate modulation, which may influence the survival of these patients, and rehabilitation can minimize this event. We tested the hypothesis that rehabilitation protocol with game console would influence the cardiac autonomic modulation of patients with Parkinson's Disease. Eight-seven volunteers were divided into two groups, control (n = 45) and Parkinson's (n = 42), they completed the study 40 volunteers in the control group (CG) and 31 patients in the Parkinson group (PG), and subjected to 24 sessions of game therapy physiotherapy, thrice a week. Analysis of autonomic HR modulation was conducted before and after the rehabilitation program using a Polar RS800CX HR sensor. For the analysis of heart rate variability the data were transferred to the Kubios HRV 2.2 program. Statistical analysis was performed in the Biostat 5.2 program, the comparison of the data by ANOVA followed by Tukey test, and the general characteristics by the chi-square test. The critical value for rejecting the null hypothesis was set at P < 0.05. HR variability in patients with PD exhibited higher influence on the sympathetic nervous system before protocol implementation and, following the protocol, patients did not attain the normality values of the control group, exhibiting a discreet improvement and maintenance of autonomic modulation of HR values. Subjects with PD exhibit less autonomic modulation of HR and the rehabilitation protocol with game therapy improved autonomic modulation of HR. Geriatr Gerontol Int 2017; ••: ••-••. © 2017 Japan Geriatrics Society.

  5. Digital modulation and achievable information rates of thru-body haptic communications

    NASA Astrophysics Data System (ADS)

    Hanisch, Natalie; Pierobon, Massimiliano

    2017-05-01

    The ever increasing biocompatibility and pervasive nature of wearable and implantable devices demand novel sustainable solutions to realize their connectivity, which can impact broad application scenarios such as in the defense, biomedicine, and entertainment fields. Where wireless electromagnetic communications are facing challenges such as device miniaturization, energy scarcity, limited range, and possibility of interception, solutions not only inspired but also based on natural communication means might result into valid alternatives. In this paper, a communication paradigm where digital information is propagated through the nervous system is proposed and analyzed on the basis of achievable information rates. In particular, this paradigm is based on an analytical framework where the response of a system based on haptic (tactile) information transmission and ElectroEncephaloGraphy (EEG)-based reception is modeled and characterized. Computational neuroscience models of the somatosensory signal representation in the brain, coupled with models of the generation and propagation of somatosensory stimulation from skin mechanoreceptors, are employed in this paper to provide a proof-of-concept evaluation of achievable performance in encoding information bits into tactile stimulation, and decoding them from the recorded brain activity. Based on these models, the system is simulated and the resulting data are utilized to train a Support Vector Machine (SVM) classifier, which is finally used to provide a proof-of-concept validation of the system performance in terms of information rates against bit error probability at the reception.

  6. Genetic modulation of RNA metabolism in Drosophilia. I. Increased rate of ribosomal RNA synthesis.

    PubMed

    Clark, S H; Strausbaugh, L D; Kiefer, B I

    1977-08-01

    It has been suggested that a particular Y chromosome which is rDNA-deficient (YbbSuVar-5) may be associated with an increased utilization of rDNA template in adult testes (Shermoen and Kiefer 1975). To extend the observations on this chromosome, experiments were designed to determine if the chromosome has an effect on rRNA synthesis in bobbed adults and on classic bobbed phenotypes (shortened and thinner scutellar bristles and delayed development). Specific activity measurements were made on rRNA extracted from adult males of the genotypes car bb/YbbSuVar-5, which are rDNA-deficient to the same extent, and from Samarkand+ isogenic (Sam+ iso), which is a wild-type stock. The resulting data demonstrated that the presence of the YbbSuVar-5 chromosome increases the rate of ribosomal RNA synthesis in adult flies. In addition, it was found that the presence of this particular Y chromosome restores wild-type bristle phenotype and development time. Appropriate genetic crosses indicate that the observed effects (increased rRNA synthesis, restoration of wild-type phenotype) are a function of this particular Y chromosome, and are not due to autosomal factors. The results of these experiments suggest that the rate of rRNA accumulation is under genetic control.

  7. Increased flow resistance and decreased flow rate in patients with acute respiratory distress syndrome: The role of autonomic nervous modulation.

    PubMed

    Chen, I-Chen; Kuo, Jane; Ko, Wen-Je; Shih, Hsin-Chin; Kuo, Cheng-Deng

    2016-01-01

    The aim of this study was to investigate the flow resistance and flow rate in patients with acute respiratory distress syndrome (ARDS) in the surgical intensive care unit and their relation with autonomic nervous modulation. Postoperative patients of lung or esophageal cancer surgery without ARDS were included as the control group (n = 11). Patients who developed ARDS after lung or esophageal cancer surgery were included as the ARDS group (n = 21). The ARDS patients were further divided into survivor and nonsurvivor subgroups according to their outcomes. All patients required intubation and mechanical ventilation. The flow rate was significantly decreased, while the flow resistance was significantly increased, in ARDS patients. The flow rate correlated significantly and negatively with positive end-expiratory pressure (PEEP), while the flow resistance correlated significantly and positively with PEEP in ARDS patients. Furthermore, the flow rate correlated significantly and negatively with the tidal volume-corrected normalized high-frequency power but correlated significantly and positively with the tidal volume-corrected low-/high-frequency power ratio. In contrast, the flow resistance correlated significantly and negatively with normalized very low-frequency power and tidal volume-corrected low-/high-frequency power ratio, but correlated significantly and positively with tidal volume-corrected normalized high-frequency power. The flow rate is decreased and the flow resistance increased in patients with ARDS. PEEP is one of the causes of increased flow resistance and decreased flow rate in patients with ARDS. Another cause of decreased flow rate and increased flow resistance in ARDS patients is the increased vagal activity and decreased sympathetic activity. The monitoring of flow rate and flow resistance during mechanical ventilation might be useful for the proper management of ARDS patients. Copyright © 2015. Published by Elsevier Taiwan LLC.

  8. Modulation of Leaf Economic Traits and Rates by Soil Properties, at Global Scale

    NASA Astrophysics Data System (ADS)

    Maire, V.; Wright, I. J.; Reich, P. B.; Batjes, N. H., Jr.; van Bodegom, P. M.; Bhaskar, R.; Santiago, L. S.; Ellsworth, D.; Niinemets, U.; Cornwell, W.

    2014-12-01

    Photosynthesis can be construed as an economic process that optimises the costs of acquisition, transport and utilisation of two substitutable photosynthetic resources: water and nitrogen. The influence of soil fertility on photosynthetic rates and leaf 'economic' traits related with H2O and N costs is poorly quantified in higher plants in comparison with the effects of climate. We set out to address this situation by quantifying the unique and shared contributions to global leaf-trait variation from soils and climate. Using a trait dataset comprising 1509 species from 288 sites, with climate and soil data derived from global datasets, we quantified the effects of soil and climate properties on photosynthetic traits: light-saturated photosynthetic rate (Aarea), stomatal conductance to water vapour (gs), leaf N and P (Narea and Parea) and specific leaf area (SLA). We used mixed regression models, multivariate analyses and variance partitioning. Along a first dimension of soil fertility, soil pH covaried positively with measures of base status and climatic aridity, and negatively with soil organic C content. Along this dimension from low to high soil pH, Narea, Parea and Aarea increased and SLA decreased. Along an independent dimension of soil fertility, gs declined and Parea increased with soil available P (Pavail). Overall, soil variables were stronger predictors of leaf traits than were climate variables, except for SLA. Importantly, soils and climate were not redundant information to explain leaf trait variation but were not additive either. Shared effects of soil and climate dominated over their independent effects on Narea and Parea, while unique effects of soils dominated for Aarea and gs. Three environmental variables were key for explaining variation in leaf traits: soil pH and Pavail, and climatic aridity. Although the reliability of global soils datasets lags behind that of climate datasets our results nonetheless provide compelling evidence that both can

  9. Loss of Breathing Modulation of Heart Rate Variability in Patients with Recent and Long Standing Diabetes Mellitus Type II.

    PubMed

    Rivera, Ana Leonor; Estañol, Bruno; Fossion, Ruben; Toledo-Roy, Juan C; Callejas-Rojas, José A; Gien-López, José A; Delgado-García, Guillermo R; Frank, Alejandro

    2016-01-01

    Healthy subjects under rhythmic breathing have heart interbeat intervals with a respiratory band in the frequency domain that can be an index of vagal activity. Diabetes Mellitus Type II (DM) affects the autonomic nervous system of patients, thus it can be expected changes on the vagal activity. Here, the influence of DM on the breathing modulation of the heart rate is evaluated by analyzing in the frequency domain heart interbeat interval (IBI) records obtained from 30 recently diagnosed, 15 long standing DM patients, and 30 control subjects during standardized clinical tests of controlled breathing at 0.1 Hz, supine rest and standing upright. Fourier spectral analysis of IBI records quantifies heart rate variability in different regions: low-frequencies (LF, 0.04-0.15 Hz), high-frequencies (HF, 0.15-0.4 Hz), and a controlled breathing peak (RP, centered around 0.1 Hz). Two new parameters are introduced: the frequency radius rf (square root of the sum of LF and HF squared) and β (power of RP divided by the sum of LF and HF). As diabetes evolves, the controlled breathing peak loses power and shifts to smaller frequencies, indicating that heart rate modulation is slower in diabetic patients than in controls. In contrast to the traditional parameters LF, HF and LF/HF, which do not show significant differences between the three populations in neither of the clinical tests, the new parameters rf and β, distinguish between control and diabetic subjects in the case of controlled breathing. Sympathetic activity that is driven by the baroreceptor reflex associated with the 0.1 Hz breathing modulations is affected in DM patients. Diabetes produces not only a rigid heartbeat with less autonomic induced variability (rf diminishes), but also alters the coupling between breathing and heart rate (reduced β), due to a progressive decline of vagal and sympathetic activity.

  10. Loss of Breathing Modulation of Heart Rate Variability in Patients with Recent and Long Standing Diabetes Mellitus Type II

    PubMed Central

    Estañol, Bruno; Fossion, Ruben; Toledo-Roy, Juan C.; Callejas-Rojas, José A.; Gien-López, José A.; Delgado-García, Guillermo R.; Frank, Alejandro

    2016-01-01

    Healthy subjects under rhythmic breathing have heart interbeat intervals with a respiratory band in the frequency domain that can be an index of vagal activity. Diabetes Mellitus Type II (DM) affects the autonomic nervous system of patients, thus it can be expected changes on the vagal activity. Here, the influence of DM on the breathing modulation of the heart rate is evaluated by analyzing in the frequency domain heart interbeat interval (IBI) records obtained from 30 recently diagnosed, 15 long standing DM patients, and 30 control subjects during standardized clinical tests of controlled breathing at 0.1 Hz, supine rest and standing upright. Fourier spectral analysis of IBI records quantifies heart rate variability in different regions: low-frequencies (LF, 0.04–0.15 Hz), high-frequencies (HF, 0.15–0.4 Hz), and a controlled breathing peak (RP, centered around 0.1 Hz). Two new parameters are introduced: the frequency radius rf (square root of the sum of LF and HF squared) and β (power of RP divided by the sum of LF and HF). As diabetes evolves, the controlled breathing peak loses power and shifts to smaller frequencies, indicating that heart rate modulation is slower in diabetic patients than in controls. In contrast to the traditional parameters LF, HF and LF/HF, which do not show significant differences between the three populations in neither of the clinical tests, the new parameters rf and β, distinguish between control and diabetic subjects in the case of controlled breathing. Sympathetic activity that is driven by the baroreceptor reflex associated with the 0.1 Hz breathing modulations is affected in DM patients. Diabetes produces not only a rigid heartbeat with less autonomic induced variability (rf diminishes), but also alters the coupling between breathing and heart rate (reduced β), due to a progressive decline of vagal and sympathetic activity. PMID:27802329

  11. DEVELOPMENT OF A LOW COST INFERENTIAL NATURAL GAS ENERGY FLOW RATE PROTOTYPE RETROFIT MODULE

    SciTech Connect

    E. Kelner; D. George; T. Morrow; T. Owen; M. Nored; R. Burkey; A. Minachi

    2005-05-01

    In 1998, Southwest Research Institute began a multi-year project to develop a working prototype instrument module for natural gas energy measurement. The module will be used to retrofit a natural gas custody transfer flow meter for energy measurement, at a cost an order of magnitude lower than a gas chromatograph. Development and evaluation of the prototype energy meter in 2002-2003 included: (1) refinement of the algorithm used to infer properties of the natural gas stream, such as heating value; (2) evaluation of potential sensing technologies for nitrogen content, improvements in carbon dioxide measurements, and improvements in ultrasonic measurement technology and signal processing for improved speed of sound measurements; (3) design, fabrication and testing of a new prototype energy meter module incorporating these algorithm and sensor refinements; and (4) laboratory and field performance tests of the original and modified energy meter modules. Field tests of the original energy meter module have provided results in close agreement with an onsite gas chromatograph. The original algorithm has also been tested at a field site as a stand-alone application using measurements from in situ instruments, and has demonstrated its usefulness as a diagnostic tool. The algorithm has been revised to use measurement technologies existing in the module to measure the gas stream at multiple states and infer nitrogen content. The instrumentation module has also been modified to incorporate recent improvements in CO{sub 2} and sound speed sensing technology. Laboratory testing of the upgraded module has identified additional testing needed to attain the target accuracy in sound speed measurements and heating value.

  12. The effect of presentation level and stimulation rate on speech perception and modulation detection for cochlear implant users.

    PubMed

    Brochier, Tim; McDermott, Hugh J; McKay, Colette M

    2017-06-01

    In order to improve speech understanding for cochlear implant users, it is important to maximize the transmission of temporal information. The combined effects of stimulation rate and presentation level on temporal information transfer and speech understanding remain unclear. The present study systematically varied presentation level (60, 50, and 40 dBA) and stimulation rate [500 and 2400 pulses per second per electrode (pps)] in order to observe how the effect of rate on speech understanding changes for different presentation levels. Speech recognition in quiet and noise, and acoustic amplitude modulation detection thresholds (AMDTs) were measured with acoustic stimuli presented to speech processors via direct audio input (DAI). With the 500 pps processor, results showed significantly better performance for consonant-vowel nucleus-consonant words in quiet, and a reduced effect of noise on sentence recognition. However, no rate or level effect was found for AMDTs, perhaps partly because of amplitude compression in the sound processor. AMDTs were found to be strongly correlated with the effect of noise on sentence perception at low levels. These results indicate that AMDTs, at least when measured with the CP910 Freedom speech processor via DAI, explain between-subject variance of speech understanding, but do not explain within-subject variance for different rates and levels.

  13. Potential force dynamics of heart rate variability reflect cardiac autonomic modulation with respect to posture, age, and breathing pattern.

    PubMed

    Mahananto, Faizal; Igasaki, Tomohiko; Murayama, Nobuki

    2015-09-01

    Various physiological and pathological conditions are correlated with cardiac autonomic function. Heart rate variability is a marker of cardiac autonomic modulation and can be measured by several methods. However, the available methods are sensitive to breathing patterns. To quantify cardiac autonomic modulation by observing the potential force dynamics of the R-R interval time series in healthy individuals. We propose two "potentials of unbalanced complex kinetic" (PUCK) parameters to quantify the characteristics of the potential force dynamics of R-R interval time series: potential strength (slope) and fluctuation size (slope standard deviations [SSD1, SSD2]). We applied this method to the series of R-R intervals obtained from 30 healthy subjects in an experimental condition that elicited cardiac autonomic (i.e., sympathetic and vagal) activation (in supine, sitting, and standing positions). Subjects were categorized into three groups by decade (i.e., 20 s, 30 s, and 40 s) to verify the cardiac autonomic differences by age. Two respiration patterns were introduced to check the influence of the pattern into the analytical results. Sympathetic modulation activation significantly increased the slope and reduced SSD1 and SSD2; these trends were confirmed in all groups. The slope is concordant with the result of the low frequency/high frequency (LF/HF) ratio in frequency components as an indicator of sympathetic modulation. No trend was observed in slope among age groups. However, SSD1 and SSD2 in the 40 s group were significantly decreased in the supine and sitting positions. The results with respect to respiration frequency showed lower sympathetic modulation as shown in the LF/HF ratio and slope, whereas higher vagal modulation as shown in the HF appeared with a longer breathing rate. PUCK can quantify the cardiac autonomic modulation in the experimental conditions of different postures. SSD1 and SSD2 are more sensitive to age than frequency components and are

  14. Substance P Differentially Modulates Firing Rate of Solitary Complex (SC) Neurons from Control and Chronic Hypoxia-Adapted Adult Rats

    PubMed Central

    Nichols, Nicole L.; Powell, Frank L.; Dean, Jay B.; Putnam, Robert W.

    2014-01-01

    NK1 receptors, which bind substance P, are present in the majority of brainstem regions that contain CO2/H+-sensitive neurons that play a role in central chemosensitivity. However, the effect of substance P on the chemosensitive response of neurons from these regions has not been studied. Hypoxia increases substance P release from peripheral afferents that terminate in the caudal nucleus tractus solitarius (NTS). Here we studied the effect of substance P on the chemosensitive responses of solitary complex (SC: NTS and dorsal motor nucleus) neurons from control and chronic hypoxia-adapted (CHx) adult rats. We simultaneously measured intracellular pH and electrical responses to hypercapnic acidosis in SC neurons from control and CHx adult rats using the blind whole cell patch clamp technique and fluorescence imaging microscopy. Substance P significantly increased the basal firing rate in SC neurons from control and CHx rats, although the increase was smaller in CHx rats. However, substance P did not affect the chemosensitive response of SC neurons from either group of rats. In conclusion, we found that substance P plays a role in modulating the basal firing rate of SC neurons but the magnitude of the effect is smaller for SC neurons from CHx adult rats, implying that NK1 receptors may be down regulated in CHx adult rats. Substance P does not appear to play a role in modulating the firing rate response to hypercapnic acidosis of SC neurons from either control or CHx adult rats. PMID:24516602

  15. Improved symbol rate identification method for on-off keying and advanced modulation format signals based on asynchronous delayed sampling

    NASA Astrophysics Data System (ADS)

    Cui, Sheng; Jin, Shang; Xia, Wenjuan; Ke, Changjian; Liu, Deming

    2015-11-01

    Symbol rate identification (SRI) based on asynchronous delayed sampling is accurate, cost-effective and robust to impairments. For on-off keying (OOK) signals the symbol rate can be derived from the periodicity of the second-order autocorrelation function (ACF2) of the delay tap samples. But it is found that when applied this method to advanced modulation format signals with auxiliary amplitude modulation (AAM), incorrect results may be produced because AAM has significant impact on ACF2 periodicity, which makes the symbol period harder or even unable to be correctly identified. In this paper it is demonstrated that for these signals the first order autocorrelation function (ACF1) has stronger periodicity and can be used to replace ACF2 to produce more accurate and robust results. Utilizing the characteristics of the ACFs, an improved SRI method is proposed to accommodate both OOK and advanced modulation formant signals in a transparent manner. Furthermore it is proposed that by minimizing the peak to average ratio (PAPR) of the delay tap samples with an additional tunable dispersion compensator (TDC) the limited dispersion tolerance can be expanded to desired values.

  16. Characterization of pulse amplitude and pulse rate modulation for a human vestibular implant during acute electrical stimulation

    NASA Astrophysics Data System (ADS)

    Nguyen, T. A. K.; DiGiovanna, J.; Cavuscens, S.; Ranieri, M.; Guinand, N.; van de Berg, R.; Carpaneto, J.; Kingma, H.; Guyot, J.-P.; Micera, S.; Perez Fornos, A.

    2016-08-01

    Objective. The vestibular system provides essential information about balance and spatial orientation via the brain to other sensory and motor systems. Bilateral vestibular loss significantly reduces quality of life, but vestibular implants (VIs) have demonstrated potential to restore lost function. However, optimal electrical stimulation strategies have not yet been identified in patients. In this study, we compared the two most common strategies, pulse amplitude modulation (PAM) and pulse rate modulation (PRM), in patients. Approach. Four subjects with a modified cochlear implant including electrodes targeting the peripheral vestibular nerve branches were tested. Charge-equivalent PAM and PRM were applied after adaptation to baseline stimulation. Vestibulo-ocular reflex eye movement responses were recorded to evaluate stimulation efficacy during acute clinical testing sessions. Main results. PAM evoked larger amplitude eye movement responses than PRM. Eye movement response axes for lateral canal stimulation were marginally better aligned with PRM than with PAM. A neural network model was developed for the tested stimulation strategies to provide insights on possible neural mechanisms. This model suggested that PAM would consistently cause a larger ensemble firing rate of neurons and thus larger responses than PRM. Significance. Due to the larger magnitude of eye movement responses, our findings strongly suggest PAM as the preferred strategy for initial VI modulation.

  17. Use of Melt Flow Rate Test in Reliability Study of Thermoplastic Encapsulation Materials in Photovoltaic Modules

    SciTech Connect

    Moseley, J.; Miller, D.; Shah, Q.-U.-A. S. J.; Sakurai, K.; Kempe, M.; Tamizhmani, G.; Kurtz, S.

    2011-10-01

    Use of thermoplastic materials as encapsulants in photovoltaic (PV) modules presents a potential concern in terms of high temperature creep, which should be evaluated before thermoplastics are qualified for use in the field. Historically, the issue of creep has been avoided by using thermosetting polymers as encapsulants, such as crosslinked ethylene-co-vinyl acetate (EVA). Because they lack crosslinked networks, however, thermoplastics may be subject to phase transitions and visco-elastic flow at the temperatures and mechanical stresses encountered by modules in the field, creating the potential for a number of reliability and safety issues. Thermoplastic materials investigated in this study include PV-grade uncured-EVA (without curing agents and therefore not crosslinked); polyvinyl butyral (PVB); thermoplastic polyurethane (TPU); and three polyolefins (PO), which have been proposed for use as PV encapsulation. Two approaches were used to evaluate the performance of these materials as encapsulants: module-level testing and a material-level testing.

  18. Submaximal exercise intensity modulates acute post-exercise heart rate variability.

    PubMed

    Michael, Scott; Jay, Ollie; Halaki, Mark; Graham, Kenneth; Davis, Glen M

    2016-04-01

    This study investigated whether short-term heart rate variability (HRV) can be used to differentiate between the immediate recovery periods following three different intensities of preceding exercise. 12 males cycled for 8 min at three intensities: LOW (40-45 %), MOD (75-80 %) and HIGH (90-95 %) of heart rate (HR) reserve. HRV was assessed during exercise and throughout 10-min seated recovery. 1-min HR recovery was reduced following greater exercise intensities when expressed as R-R interval (RRI, ms) (p < 0.001), but not b min(-1) (p = 0.217). During exercise, the natural logarithm of root mean square of successive differences (Ln-RMSSD) was higher during LOW (1.66 ± 0.47 ms) relative to MOD (1.14 ± 0.32 ms) and HIGH (1.30 ± 0.25 ms) (p ≤ 0.037). Similar results were observed for high-frequency spectra (Ln-HF-LOW: 2.9 ± 1.0; MOD: 1.6 ± 0.6; HIGH: 1.6 ± 0.3 ms(2), p < 0.001). By 1-min recovery, higher preceding exercise intensities resulted in lower HRV amongst all three intensities for Ln-RMSSD (LOW: 3.45 ± 0.58; MOD: 2.34 ± 0.81; HIGH: 1.66 ± 0.78 ms, p < 0.001) and Ln-HF (LOW: 6.0 ± 1.0; MOD: 4.3 ± 1.4; HIGH: 2.8 ± 1.4 ms(2), p < 0.001). Similarly, by 1-min recovery 'HR-corrected' HRV (Ln-RMSSD: RRI × 10(3)) was different amongst all three intensities (LOW: 3.64 ± 0.49; MOD: 2.90 ± 0.65; HIGH: 2.40 ± 0.67, p < 0.001). These differences were maintained throughout 10-min recovery (p ≤ 0.027). Preceding exercise intensity has a graded effect on recovery HRV measures reflecting cardiac vagal activity, even after correcting for the underlying HR. The immediate recovery following exercise is a potentially useful period to investigate autonomic activity, as multiple levels of autonomic activity can be clearly differentiated between using HRV. When investigating post-exercise HRV it is critical to account for the relative exercise intensity.

  19. Exercise intensity modulates brachial artery retrograde blood flow and shear rate during leg cycling in hypoxia

    PubMed Central

    Iwamoto, Erika; Katayama, Keisho; Ishida, Koji

    2015-01-01

    The purpose of this study was to elucidate the effect of exercise intensity on retrograde blood flow and shear rate (SR) in an inactive limb during exercise under normoxic and hypoxic conditions. The subjects performed two maximal exercise tests on a semi-recumbent cycle ergometer to estimate peak oxygen uptake (O2peak) while breathing normoxic (inspired oxygen fraction [FIO2 = 0.21]) and hypoxic (FIO2 = 0.12 or 0.13) gas mixtures. Subjects then performed four exercise bouts at the same relative intensities (30 and 60% O2peak) for 30 min under normoxic or hypoxic conditions. Brachial artery diameter and blood velocity were simultaneously recorded, using Doppler ultrasonography. Retrograde SR was enhanced with increasing exercise intensity under both conditions at 10 min of exercise. Thereafter, retrograde blood flow and SR in normoxia returned to pre-exercise levels, with no significant differences between the two exercise intensities. In contrast, retrograde blood flow and SR in hypoxia remained significantly elevated above baseline and was significantly greater at 60% than at 30% O2peak. We conclude that differences in exercise intensity affect brachial artery retrograde blood flow and SR during prolonged exercise under hypoxic conditions. PMID:26038470

  20. Exercise intensity modulates brachial artery retrograde blood flow and shear rate during leg cycling in hypoxia.

    PubMed

    Iwamoto, Erika; Katayama, Keisho; Ishida, Koji

    2015-06-01

    The purpose of this study was to elucidate the effect of exercise intensity on retrograde blood flow and shear rate (SR) in an inactive limb during exercise under normoxic and hypoxic conditions. The subjects performed two maximal exercise tests on a semi-recumbent cycle ergometer to estimate peak oxygen uptake (V˙O2peak) while breathing normoxic (inspired oxygen fraction [FIO2 = 0.21]) and hypoxic (FIO2 = 0.12 or 0.13) gas mixtures. Subjects then performed four exercise bouts at the same relative intensities (30 and 60% V˙O2peak) for 30 min under normoxic or hypoxic conditions. Brachial artery diameter and blood velocity were simultaneously recorded, using Doppler ultrasonography. Retrograde SR was enhanced with increasing exercise intensity under both conditions at 10 min of exercise. Thereafter, retrograde blood flow and SR in normoxia returned to pre-exercise levels, with no significant differences between the two exercise intensities. In contrast, retrograde blood flow and SR in hypoxia remained significantly elevated above baseline and was significantly greater at 60% than at 30% V˙O2peak. We conclude that differences in exercise intensity affect brachial artery retrograde blood flow and SR during prolonged exercise under hypoxic conditions. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  1. Tai Chi Chuan modulates heart rate variability during abdominal breathing in elderly adults.

    PubMed

    Wei, Gao-Xia; Li, You-Fa; Yue, Xiao-Lin; Ma, Xiao; Chang, Yu-Kai; Yi, Long-Yan; Li, Jing-Cheng; Zuo, Xi-Nian

    2016-03-01

    Tai Chi Chuan (TCC) practice is currently intentionally applied in clinical populations, especially those with cardiovascular diseases because of its potential benefits on the autonomic nervous system. The long-term effect of TCC practice on heart rate variability (HRV) remains largely unknown. In this study, we recruited 23 TCC practitioners whose experience averaged approximately 21 years and 19 controls matched by age, sex and education to examine the effect of TCC practice on the autonomic nervous system during a resting state and during an abdominal breathing state. HRV was measured by traditional electrocardiogram (ECG) recording. The results showed that the low frequency, total power frequency, and normalized low frequency components and the low-frequency/high-frequency ratio were significantly higher, whereas the normalized high frequency was significantly lower in the TCC practitioners relative to controls during the abdominal breathing state. However, we did not detect any significant difference in the HRV measures during the resting state between the two groups. Additionally, TCC experience did not correlate with HRV components either in the abdominal state or the resting state in the TCC group. Considering all of these findings, we suggest that TCC improves vagal activity and the balance between sympathetic and parasympathetic activity during the relaxation state. This study also provides direct physiological evidence for the role of TCC practice in relaxation.

  2. Toll-Like Receptors 2 and 4 Modulate Autonomic Control of Heart Rate and Energy Metabolism

    PubMed Central

    Okun, Eitan; Griffioen, Kathleen J.; Sarah, Rothman; Wan, Ruiqian; Cong, Wei-Na; De Cabo, Rafael; Montalvo, Alejandro Martin; Levette, Andrew; Maudsley, Stuart; Martin, Bronwen; Arumugam, Thiruma Valavan; Mattson, Mark P.

    2013-01-01

    Toll-like receptors (TLR) are innate immune receptors typically activated by microbial-associated molecular patterns (MAMPs) during infection or damage-associated molecular patterns (DAMPs) as a result of tissue injury. Recent findings suggest that TLR2 and TLR4 signaling play important roles in developmental and adult neuroplasticity, and in learning and memory. In addition, activation of TLR2 and TLR4 worsens ischemic injury to the heart and brain in animal models of myocardial infarction and stroke. TLR activation is also implicated in thermoregulation and fever in response to infection. However, it is not known whether TLRs participate in the regulation of the sympathetic and/or parasympathetic components of the autonomic nervous system (ANS). Here we provide evidence that TLR2 and TLR4 influence autonomic regulation of heart rate (HR) body temperature and energy metabolism in mice. We show that mice lacking TLR2 or TLR4 exhibit reduced basal HR, which results from an increase of parasympathetic tone. In addition, thermoregulatory responses to stress are altered in TLR2−/− and TLR4−/− mice, and brown fat-dependent thermoregulation is altered in TLR4−/− mice. Moreover, TLR2−/− and TLR4−/− mice consume less food and exhibit a greater mass compared to wild type mice. Collectively, our findings suggest important roles for TLR2 and TLR4 in the ANS regulation of cardiovascular function, thermoregulation, and energy metabolism. PMID:24145051

  3. Measures of Student Success: Can We Predict Module-Completion Rates? Occasional Paper

    ERIC Educational Resources Information Center

    Learned, Jeanette

    2010-01-01

    There are many factors which might cause a student to drop out of a course of study; some of these are preventable. This paper describes the piloting of a survey tool designed to identify students at risk of not completing. Attendance was found to be the strongest predictor of module completion; low or declining scores on the survey were also…

  4. Picosecond optical pulse generation at gigahertz rates by direct modulation of a semiconductor laser

    NASA Technical Reports Server (NTRS)

    Auyeung, J.

    1981-01-01

    We report the generation of picosecond pulses by the direct modulation of a buried heterostructure GaAlAs diode laser. Pulse width of 28 ps is achieved at a repetition frequency of 2.5 GHz. Pulse width dependence on the experimental parameters is described.

  5. DEVELOPMENT OF A LOW-COST INFERENTIAL NATURAL GAS ENERGY FLOW RATE PROTOTYPE RETROFIT MODULE

    SciTech Connect

    E. Kelner; T.E. Owen; D.L. George; A. Minachi; M.G. Nored; C.J. Schwartz

    2004-03-01

    In 1998, Southwest Research Institute{reg_sign} began a multi-year project co-funded by the Gas Research Institute (GRI) and the U.S. Department of Energy. The project goal is to develop a working prototype instrument module for natural gas energy measurement. The module will be used to retrofit a natural gas custody transfer flow meter for energy measurement, at a cost an order of magnitude lower than a gas chromatograph. Development and evaluation of the prototype retrofit natural gas energy flow meter in 2000-2001 included: (1) evaluation of the inferential gas energy analysis algorithm using supplemental gas databases and anticipated worst-case gas mixtures; (2) identification and feasibility review of potential sensing technologies for nitrogen diluent content; (3) experimental performance evaluation of infrared absorption sensors for carbon dioxide diluent content; and (4) procurement of a custom ultrasonic transducer and redesign of the ultrasonic pulse reflection correlation sensor for precision speed-of-sound measurements. A prototype energy meter module containing improved carbon dioxide and speed-of-sound sensors was constructed and tested in the GRI Metering Research Facility at SwRI. Performance of this module using transmission-quality natural gas and gas containing supplemental carbon dioxide up to 9 mol% resulted in gas energy determinations well within the inferential algorithm worst-case tolerance of {+-}2.4 Btu/scf (nitrogen diluent gas measured by gas chromatograph). A two-week field test was performed at a gas-fired power plant to evaluate the inferential algorithm and the data acquisition requirements needed to adapt the prototype energy meter module to practical field site conditions.

  6. Decreased autonomic modulation of heart rate and altered cardiac sympathovagal balance in patients with Cushing's syndrome: role of endogenous hypercortisolism.

    PubMed

    Chandran, Dinu S; Ali, Naseer; Jaryal, Ashok Kumar; Jyotsna, Viveka P; Deepak, Kishore Kumar

    2013-01-01

    Endogenous Cushing's syndrome is associated with a higher risk of cardiovascular morbidity and mortality. Previous literature suggested multiple possible links by which hypercortisolism may alter the autonomic control of cardiovascular functions. We investigated the impact of chronic endogenous hypercortisolism on the autonomic regulation of cardiac functions by short-term heart rate variability analysis. Eighteen patients with endogenous Cushing's syndrome and 20 age-, gender- and BMI-matched controls participated in the study. ECG signal was acquired in lead II configuration for 5 min and heart rate variability assessment was made in both time and frequency domain using the extracted RR interval data. All time and frequency domain measures of heart rate variability were significantly (p < 0.05) lower in the patient group compared to the control group. The patient group had an altered sympathovagal balance with low frequency/high frequency band ratio significantly higher than the control group [1.857 (0.6747-2.610) vs. 0.8581 (0.4779-1.352); p = 0.0253]. A significant negative correlation was obtained between normalized high frequency power of heart rate variability and basal cortisol levels (r = -0.6594; p = 0.0029). Multiple linear regression analysis identified age, disease duration (in months), basal cortisol levels and systolic blood pressure as independent predictors of normalized high frequency power. Findings of the study clearly portrayed the diminished autonomic modulation of heart rate in endogenous Cushing's syndrome and its possible relationship with hypercortisolism as the main causative factor. Diminished heart rate variability may be an indicator of the increased risk of cardiac mortality in these patients. Copyright © 2013 S. Karger AG, Basel.

  7. Development of inhibitory mechanisms underlying selectivity for the rate and direction of frequency-modulated sweeps in the auditory cortex.

    PubMed

    Razak, Khaleel A; Fuzessery, Zoltan M

    2007-02-14

    Although it is known that neural selectivity for species-specific vocalizations changes during development, the mechanisms underlying such changes are not known. This study followed the development of mechanisms underlying selectivity for the direction and rate of frequency-modulated (FM) sweeps in the auditory cortex of the pallid bat, a species that uses downward FM sweeps to echolocate. In the adult cortex, direction and rate selectivity arise as a result of different spectral and temporal properties of low-frequency inhibition (LFI) and high-frequency inhibition (HFI). A narrow band of delayed HFI shapes rate selectivity for downward FM sweeps. A broader band of early LFI shapes direction selectivity. Here we asked whether these differences in LFI and HFI are present at the onset of hearing in the echolocation range or whether the differences develop slowly. We also studied how the development of properties of inhibitory frequencies influences FM rate and direction selectivity. We found that adult-like FM rate selectivity is present at 2 weeks after birth, whereas direction selectivity matures 12 weeks after birth. The different developmental time course for direction and rate selectivity is attributable to the differences in the development of LFI and HFI. Arrival time and bandwidth of HFI are adult-like at 2 weeks. Average arrival time of LFI gradually becomes faster and bandwidth becomes broader between 2 and 12 weeks. Thus, two properties of FM sweeps that are important for vocalization selectivity follow different developmental time courses attributable to the differences in the development of underlying inhibitory mechanisms.

  8. Time-gated single-photon detection module with 110 ps transition time and up to 80 MHz repetition rate

    SciTech Connect

    Buttafava, Mauro Boso, Gianluca; Ruggeri, Alessandro; Tosi, Alberto; Dalla Mora, Alberto

    2014-08-15

    We present the design and characterization of a complete single-photon counting module capable of time-gating a silicon single-photon avalanche diode with ON and OFF transition times down to 110 ps, at repetition rates up to 80 MHz. Thanks to this sharp temporal filtering of incoming photons, it is possible to reject undesired strong light pulses preceding (or following) the signal of interest, allowing to increase the dynamic range of optical acquisitions up to 7 decades. A complete experimental characterization of the module highlights its very flat temporal response, with a time resolution of the order of 30 ps. The instrument is fully user-configurable via a PC interface and can be easily integrated in any optical setup, thanks to its small and compact form factor.

  9. Preserved autonomic heart rate modulation in chronic renal failure patients in response to hemodialysis and orthostatism.

    PubMed

    Lerma, Claudia; González, Hortensia; Pérez-Grovas, Hector; José, Marco V; Infante, Oscar

    2015-04-01

    The aim of this work was to measure the impact of active orthostatism and hemodialysis (HD) upon heart rate variability (HRV) in chronic renal failure (CRF) patients before and after HD. Nineteen healthy subjects (age 27 ± 8 years old, 13 were female) and 19 unmedicated CRF patients with HD thrice per week (average HD vintage = 12 months, age 32 ± 9 years old, 11 were female) were included. Five-minute length HRV time series were obtained during supine position and orthostatism. Recordings from CRF patients were obtained before and after HD. Time domain and frequency domain HRV indexes were compared by analysis of variance. The correlation between each HRV index and change in sympathetic weighting induced by different maneuvers was tested by Kendall's Tau correlation. A p value <0.05 was considered statistically significant. HRV indexes which are associated with sympathetic activity increased in response to orthostatism in the healthy group, e.g., low-frequency to high-frequency (LF/HF) ratio, Ln (LF/HF) = -0.3 ± 0.9 versus 0.9 ± 0.9. CRF patients before HD had higher sympathetic weighting than healthy participants, even in supine position, Ln (LF/HF) = 0.6 ± 1.0, but such a difference was accentuated during orthostatism, Ln (LF/HF) = 1.5 ± 1.0, and after HD: Ln (LF/HF) = 0.8 ± 1.3 (supine position) and 2.5 ± 2.1 (orthostatism). All HRV indexes were associated with increments in sympathetic weighting between maneuvers (Kendall's correlations absolute values ≥ 0.24). Unmedicated young CRF patients treated with hemodynamically stable maintenance HD showed preserved capacity of autonomic response (with gradual sympathetic increases) induced by cardiovascular challenges such as orthostatism and HD.

  10. Gravitational focusing and substructure effects on the rate modulation in direct dark matter searches

    SciTech Connect

    Nobile, Eugenio Del; Gelmini, Graciela B.; Witte, Samuel J.

    2015-08-21

    We study how gravitational focusing (GF) of dark matter by the Sun affects the annual and biannual modulation of the expected signal in non-directional direct dark matter searches, in the presence of dark matter substructure in the local dark halo. We consider the Sagittarius stream and a possible dark disk, and show that GF suppresses some, but not all, of the distinguishing features that would characterize substructure of the dark halo were GF neglected.

  11. Gravitational focusing and substructure effects on the rate modulation in direct dark matter searches

    SciTech Connect

    Nobile, Eugenio Del; Gelmini, Graciela B.; Witte, Samuel J. E-mail: gelmini@physics.ucla.edu

    2015-08-01

    We study how gravitational focusing (GF) of dark matter by the Sun affects the annual and biannual modulation of the expected signal in non-directional direct dark matter searches, in the presence of dark matter substructure in the local dark halo. We consider the Sagittarius stream and a possible dark disk, and show that GF suppresses some, but not all, of the distinguishing features that would characterize substructure of the dark halo were GF neglected.

  12. Metal-to-Insulator Transition in Anatase TiO2 Thin Films Induced by Growth Rate Modulation

    SciTech Connect

    Tachikawa, T; Minohara, M.; Nakanishi, Y.; Hikita, Y.; Yoshita, M.; Akiyama, H.; Bell, C.; Hwang, H.Y.

    2012-06-21

    We demonstrate control of the carrier density of single phase anatase TiO{sub 2} thin films by nearly two orders of magnitude by modulating the growth kinetics during pulsed laser deposition, under fixed thermodynamic conditions. The resistivity and the intensity of the photoluminescence spectra of these TiO{sub 2} samples, both of which correlate with the number of oxygen vacancies, are shown to depend strongly on the growth rate. A quantitative model is used to explain the carrier density changes.

  13. Effects of heart rate variability biofeedback on cardiovascular responses and autonomic sympathovagal modulation following stressor tasks in prehypertensives.

    PubMed

    Chen, S; Sun, P; Wang, S; Lin, G; Wang, T

    2016-02-01

    Autonomic dysfunction is implicated in prehypertension, and previous studies have suggested that therapies that improve modulation of sympathovagal balance, such as biofeedback and slow abdominal breathing, are effective in patients with prehypertension at rest. However, considering that psychophysiological stressors may be associated with greater cardiovascular risk in prehypertensives, it is important to investigate whether heart rate variability biofeedback (HRV-BF) results in equivalent effects on autonomic cardiovascular responses control during stressful conditions in prehypertensives. A total of 32 college students with prehypertension were enrolled and randomly assigned to HRV-BF (n=12), slow abdominal breathing (SAB, n=10) or no treatment (control, n=10) groups. Then, a training experiment consisting of 15 sessions was employed to compare the effect of each intervention on the following cardiovascular response indicators before and after intervention: heart rate (HR); heart rate variability (HRV) components; blood volume pulse amplitude (BVPamp); galvanic skin response; respiration rate (RSP); and blood pressure. In addition, the cold pressor test and the mental arithmetic challenge test were also performed over two successive days before and after the invention as well as after 3 months of follow-up. A significant decrease in HR and RSP and a significant increase in BVPamp were observed after the HRV-BF intervention (P<0.001). For the HRV analysis, HRV-BF significantly reduced the ratio of low-frequency power to high-frequency power (the LF/HF ratio, P<0.001) and increased the normalized high-frequency power (HFnm) (P<0.001) during the stress tests, and an added benefit over SAB by improving HRV was also observed. In the 3-month follow-up study, similar effects on RSP, BVPamp, LF/HF and HFnm were observed in the HRV-BF group compared with the SAB group. HRV-BF training contributes to the beneficial effect of reducing the stress-related cardiovascular

  14. Demodulator for binary-phase modulated signals having a variable clock rate

    NASA Technical Reports Server (NTRS)

    Wu, Ta Tzu (Inventor)

    1976-01-01

    Method and apparatus for demodulating binary-phase modulated signals recorded on a magnetic stripe on a card as the card is manually inserted into a card reader. Magnetic transitions are sensed as the card is read and the time interval between immediately preceeding basic transitions determines the duration of a data sampling pulse which detects the presence or absence of an intermediate transition pulse indicative of two respective logic states. The duration of the data sampling pulse is approximately 75 percent of the preceeding interval between basic transitions to permit tracking succeeding time differences in basic transition intervals of up to approximately 25 percent.

  15. NK1-receptor-expressing paraventricular nucleus neurones modulate daily variation in heart rate and stress-induced changes in heart rate variability.

    PubMed

    Feetham, Claire H; Barrett-Jolley, Richard

    2014-12-01

    The paraventricular nucleus of the hypothalamus (PVN) is an established center of cardiovascular control, receiving projections from other nuclei of the hypothalamus such as the dorsomedial hypothalamus and the suprachiasmatic nucleus. The PVN contains a population of "pre-autonomic neurones" which project to the intermediolateralis of the spinal cord and increase sympathetic activity, blood pressure, and heart rate. These spinally projecting neurones express a number of membrane receptors including GABA and substance P NK1 receptors. Activation of NK1-expressing neurones increases heart rate, blood pressure, and sympathetic activity. However, their role in the pattern of overall cardiovascular control remains unknown. In this work, we use specific saporin lesion of NK1-expressing PVN rat neurones with SSP-SAP and telemetrically measure resting heart rate and heart rate variability (HRV) parameters in response to mild psychological stress. The HRV parameter "low frequency/high frequency ratio" is often used as an indicator of sympathetic activity and is significantly increased with psychological stress in control rats (0.84 ± 0.14 to 2.02 ± 0.15; P < 0.001; n = 3). We find the stress-induced increase in this parameter to be blunted in the SSP-SAP-lesioned rats (0.83 ± 0.09 to 0.93 ± 0.21; P > 0.05; n = 3). We also find a shift in daily variation of heart rate rhythm and conclude that NK1-expressing PVN neurones are involved with coupling of the cardiovascular system to daily heart rate variation and the sympathetic response to psychological stress. © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  16. Pitch of amplitude-modulated irregular-rate stimuli in acoustic and electric hearing

    NASA Astrophysics Data System (ADS)

    van Wieringen, Astrid; Carlyon, Robert P.; Long, Christopher J.; Wouters, Jan

    2003-09-01

    The pitch of stimuli was studied under conditions where place-of-excitation was held constant, and where pitch was therefore derived from ``purely temporal'' cues. In experiment 1, the acoustical and electrical pulse trains consisted of pulses whose amplitudes alternated between a high and a low value, and whose interpulse intervals alternated between 4 and 6 ms. The attenuated pulses occurred after the 4-ms intervals in condition A, and after the 6-ms intervals in condition B. For both normal-hearing subjects and cochlear implantees, the period of an isochronous pulse train equal in pitch to this ``4-6'' stimulus increased from near 6 ms at the smallest modulation depth to nearly 10 ms at the largest depth. Additionally, the modulated pulse trains in condition A were perceived as being lower in pitch than those in condition B. Data are interpreted in terms of increased refractoriness in condition A, where the larger pulses are more closely followed by the smaller ones than in condition B. Consistent with this conclusion, the A-B difference was reduced at longer interpulse intervals. These findings provide a measure of supra-threshold effects of refractoriness on pitch perception, and increase our understanding of coding of temporal information in cochlear implant speech processing schemes.

  17. Light-Limited Growth Rate Modulates Nitrate Inhibition of Dinitrogen Fixation in the Marine Unicellular Cyanobacterium Crocosphaera watsonii

    PubMed Central

    Garcia, Nathan S.; Hutchins, David A.

    2014-01-01

    Biological N2 fixation is the dominant supply of new nitrogen (N) to the oceans, but is often inhibited in the presence of fixed N sources such as nitrate (NO3−). Anthropogenic fixed N inputs to the ocean are increasing, but their effect on marine N2 fixation is uncertain. Thus, global estimates of new oceanic N depend on a fundamental understanding of factors that modulate N source preferences by N2-fixing cyanobacteria. We examined the unicellular diazotroph Crocosphaera watsonii (strain WH0003) to determine how the light-limited growth rate influences the inhibitory effects of fixed N on N2 fixation. When growth (µ) was limited by low light (µ = 0.23 d−1), short-term experiments indicated that 0.4 µM NH4+ reduced N2-fixation by ∼90% relative to controls without added NH4+. In fast-growing, high-light-acclimated cultures (µ = 0.68 d−1), 2.0 µM NH4+ was needed to achieve the same effect. In long-term exposures to NO3−, inhibition of N2 fixation also varied with growth rate. In high-light-acclimated, fast-growing cultures, NO3− did not inhibit N2-fixation rates in comparison with cultures growing on N2 alone. Instead NO3− supported even faster growth, indicating that the cellular assimilation rate of N2 alone (i.e. dinitrogen reduction) could not support the light-specific maximum growth rate of Crocosphaera. When growth was severely light-limited, NO3− did not support faster growth rates but instead inhibited N2-fixation rates by 55% relative to controls. These data rest on the basic tenet that light energy is the driver of photoautotrophic growth while various nutrient substrates serve as supports. Our findings provide a novel conceptual framework to examine interactions between N source preferences and predict degrees of inhibition of N2 fixation by fixed N sources based on the growth rate as controlled by light. PMID:25503244

  18. Light-limited growth rate modulates nitrate inhibition of dinitrogen fixation in the marine unicellular cyanobacterium Crocosphaera watsonii.

    PubMed

    Garcia, Nathan S; Hutchins, David A

    2014-01-01

    Biological N2 fixation is the dominant supply of new nitrogen (N) to the oceans, but is often inhibited in the presence of fixed N sources such as nitrate (NO3-). Anthropogenic fixed N inputs to the ocean are increasing, but their effect on marine N2 fixation is uncertain. Thus, global estimates of new oceanic N depend on a fundamental understanding of factors that modulate N source preferences by N2-fixing cyanobacteria. We examined the unicellular diazotroph Crocosphaera watsonii (strain WH0003) to determine how the light-limited growth rate influences the inhibitory effects of fixed N on N2 fixation. When growth (µ) was limited by low light (µ = 0.23 d-1), short-term experiments indicated that 0.4 µM NH4+ reduced N2-fixation by ∼90% relative to controls without added NH4+. In fast-growing, high-light-acclimated cultures (µ = 0.68 d-1), 2.0 µM NH4+ was needed to achieve the same effect. In long-term exposures to NO3-, inhibition of N2 fixation also varied with growth rate. In high-light-acclimated, fast-growing cultures, NO3- did not inhibit N2-fixation rates in comparison with cultures growing on N2 alone. Instead NO3- supported even faster growth, indicating that the cellular assimilation rate of N2 alone (i.e. dinitrogen reduction) could not support the light-specific maximum growth rate of Crocosphaera. When growth was severely light-limited, NO3- did not support faster growth rates but instead inhibited N2-fixation rates by 55% relative to controls. These data rest on the basic tenet that light energy is the driver of photoautotrophic growth while various nutrient substrates serve as supports. Our findings provide a novel conceptual framework to examine interactions between N source preferences and predict degrees of inhibition of N2 fixation by fixed N sources based on the growth rate as controlled by light.

  19. High-rate synthesis of Si nanowires using modulated induction thermal plasmas

    NASA Astrophysics Data System (ADS)

    Ishisaka, Yosuke; Kodama, Naoto; Kita, Kentaro; Tanaka, Yasunori; Uesugi, Yoshihiko; Ishijima, Tatsuo; Sueyasu, Shiori; Watanabe, Shu; Nakamura, Keitaro

    2017-09-01

    Using 20 kW Ar–H2 pulse-modulated induction thermal plasma (PMITP) with time-controlled feeding of feedstock (TCFF), numerous Si nanowires were synthesized rapidly at 1,000 mg h‑1 without the intentional addition of catalysts. The PMITP + TCFF method is our original method for nanomaterial synthesis. The PMITP periodically provides a unique field including higher-temperature plasma during “on-time” and a lower-temperature plasma during “off-time”. For rapid and efficient evaporation, metal-grade Si powder feedstock was intermittently injected synchronously into the generated Ar–H2 PMITP. The synthesized products were analyzed using various analytical techniques. The synthesized products were Si nanowires 10–30 nm in diameter with a SiO x surface layer.

  20. Effects of Patrol Operation on Hydration Status and Autonomic Modulation of Heart Rate of Brazilian Peacekeepers in Haiti.

    PubMed

    Duarte, Antonio F A; Morgado, Jairo J M

    2015-11-01

    The stress of operational missions may challenge the maintenance of body homeostasis, affecting soldiers' cardiac autonomic control, promoting dehydration, and compromising performance. Therefore, we aimed to determine the effects of peacekeeper patrol operation in Haiti on soldiers' hydration status and cardiac autonomic modulation, and to determine whether fluctuations in autonomic modulation were associated with changes in hydration status, energy expenditure (EE), and aerobic fitness (V[Combining Dot Above]O2max). A group of 20 soldiers (23.5 ± 4.7 years; V[Combining Dot Above]O2max 52.9 ± 4.5 ml·kg⁻¹·min⁻¹) completed an operational patrol mission with a mean duration of 160.6 ± 28.6 minutes. Before (Pre) and after (Post) the operation, the soldiers' body masses (BMs) were measured and 5-minute heart rate interbeat (R-R) intervals were recorded at rest to estimate heart rate variability (low-frequency [LF] and high-frequency [HF] power, and sympathovagal balance [LF/HF]). During the mission, EE was estimated using heart rate (HR) monitors. Changes from Pre to Post in BM (%BM loss) and LF/HF (ΔLF/HF) were used to evaluate the soldiers' dehydration levels and autonomic modulation, respectively. The mean EE was 711.0 ± 208.7 kcal. From pre to post, increases (p < 0.01) were noted in LF normalized units (n.u.) and LF/HF and decreases (p < 0.01) were noted in BM, R-R interval, and HF n.u. The variation in ΔLF/HF correlated with EE (r = 0.49; p = 0.02), V[Combining Dot Above]O2max (r = -0.42; p = 0.05), and %BM loss (r = 0.53; p = 0.02). The results demonstrated that an operational peacekeeper patrol with an approximate duration of 160 minutes promoted both dehydration and an imbalance in the autonomic modulation of soldiers' HR. The reduction in sympathovagal balance correlated with EE, dehydration, and aerobic conditioning.

  1. Impact of small MU/segment and dose rate on delivery accuracy of volumetric-modulated arc therapy (VMAT).

    PubMed

    Huang, Long; Zhuang, Tingliang; Mastroianni, Anthony; Djemil, Toufik; Cui, Taoran; Xia, Ping

    2016-05-01

    Volumetric-modulated arc therapy (VMAT) plans may require more control points (or segments) than some of fixed-beam IMRT plans that are created with a limited number of segments. Increasing number of control points in a VMAT plan for a given prescription dose could create a large portion of the total number of segments with small number monitor units (MUs) per segment. The purpose of this study is to investigate the impact of the small number MU/segment on the delivery accuracy of VMAT delivered with various dose rates. Ten patient datasets were planned for hippocampus sparing for whole brain irradiation. For each dataset, two VMAT plans were created with maximum dose rates of 600 MU/min (the maximum field size of 21×40 cm2) and 1000 MU/min (the maximum field size of 15×15 cm2) for a daily dose of 3 Gy. Without reoptimization, the daily dose of these plans was purposely reduced to 1.5 Gy and 1.0 Gy while keeping the same total dose. Using the two dose rates and three different daily doses, six VMAT plans for each dataset were delivered to a physical phantom to investigate how the changes of dose rate and daily doses impact on delivery accuracy. Using the gamma index, we directly compared the delivered planar dose profiles with the reduced daily doses (1.5 Gy and 1.0 Gy) to the delivered planar dose at 3 Gy daily dose, delivered at dose rate of 600 MU/min and 1000 MU/min, respectively. The average numbers of segments with MU/segment≤1 were 35±8, 87±6 for VMAT-600 1.5 Gy, VMAT-600 1 Gy plans, and 30±7 and 42±6 for VMAT-1000 1.5 Gy and VMAT-1000 1 Gy plans, respectively. When delivered at 600 MU/min dose rate, the average gamma index passing rates (1%/1 mm criteria) of comparing delivered 1.5 Gy VMAT planar dose profiles to 3.0 Gy VMAT delivered planar dose profiles was 98.28%±1.66%, and the average gamma index passing rate of comparing delivered 1.0 Gy VMAT planar dose to 3.0 Gy VMAT delivered planar dose was 83.75%±4.86%. If using 2%/2 mm and 3%/3 mm

  2. Impact of small MU/segment and dose rate on delivery accuracy of volumetric-modulated arc therapy (VMAT).

    PubMed

    Huang, Long; Zhuang, Tingliang; Mastroianni, Anthony; Djemil, Toufik; Cui, Taoran; Xia, Ping

    2016-05-08

    Volumetric-modulated arc therapy (VMAT) plans may require more control points (or segments) than some of fixed-beam IMRT plans that are created with a limited number of segments. Increasing number of control points in a VMAT plan for a given prescription dose could create a large portion of the total number of segments with small number monitor units (MUs) per segment. The purpose of this study is to investigate the impact of the small number MU/segment on the delivery accuracy of VMAT delivered with various dose rates. Ten patient datasets were planned for hippocampus sparing for whole brain irradiation. For each dataset, two VMAT plans were created with maximum dose rates of 600 MU/min (the maximum field size of 21 × 40 cm2) and 1000 MU/min (the maximum field size of 15 × 15 cm2) for a daily dose of 3 Gy. Without reoptimization, the daily dose of these plans was purposely reduced to 1.5 Gy and 1.0 Gy while keeping the same total dose. Using the two dose rates and three different daily doses, six VMAT plans for each dataset were delivered to a physical phantom to investigate how the changes of dose rate and daily doses impact on delivery accuracy. Using the gamma index, we directly compared the delivered planar dose profiles with the reduced daily doses (1.5 Gy and 1.0 Gy) to the delivered planar dose at 3 Gy daily dose, delivered at dose rate of 600 MU/min and 1000 MU/min, respectively. The average numbers of segments with MU/segment ≤ 1 were 35 ± 8, 87 ± 6 for VMAT-600 1.5 Gy, VMAT-600 1 Gy plans, and 30 ± 7 and 42 ± 6 for VMAT-1000 1.5 Gy and VMAT-1000 1 Gy plans, respectively. When delivered at 600 MU/min dose rate, the average gamma index passing rates (1%/1 mm criteria) of comparing delivered 1.5 Gy VMAT planar dose profiles to 3.0 Gy VMAT delivered planar dose profiles was 98.28% ± 1.66%, and the average gamma index passing rate of comparing delivered 1.0 Gy VMAT planar dose to 3.0 Gy VMAT delivered planar dose was 83.75% ± 4.86%. If using 2%/2mm

  3. SU-E-T-421: Feasibility Study of Volumetric Modulated Arc Therapy with Constant Dose Rate for Endometrial Cancer

    SciTech Connect

    Yang, R; Wang, J

    2014-06-01

    Purpose: To investigate the feasibility, efficiency, and delivery accuracy of volumetric modulated arc therapy with constant dose rate (VMAT-CDR) for whole-pelvic radiotherapy (WPRT) of endometrial cancer. Methods: The nine-Field intensity-modulated radiotherapy (IMRT), VMAT with variable dose-rate (VMAT-VDR), and VMAT-CDR plans were created for 9 patients with endometrial cancer undergoing WPRT. The dose distribution of planning target volume (PTV), organs at risk (OARs), and normal tissue (NT) were compared. The monitor units (MUs) and treatment delivery time were also evaluated. For each VMAT-CDR plan, a dry Run was performed to assess the dosimetric accuracy with MatriXX from IBA. Results: Compared with IMRT, the VMAT-CDR plans delivered a slightly greater V20 of the bowel, bladder, pelvis bone, and NT, but significantly decreased the dose to the high-dose region of the rectum and pelvis bone. The MUs Decreased from 1105 with IMRT to 628 with VMAT-CDR. The delivery time also decreased from 9.5 to 3.2 minutes. The average gamma pass rate was 95.6% at the 3%/3 mm criteria with MatriXX pretreatment verification for 9 patients. Conclusion: VMAT-CDR can achieve comparable plan quality with significant shorter delivery time and smaller number of MUs compared with IMRT for patients with endometrial cancer undergoing WPRT. It can be accurately delivered and be an alternative to IMRT on the linear accelerator without VDR capability. This work is supported by the grant project, National Natural; Science Foundation of China (No. 81071237)

  4. Improved color purity and electroluminescent efficiency obtained by modulating thicknesses and evaporation rates of hole block and electron transport layers

    NASA Astrophysics Data System (ADS)

    Zhou, Liang; Deng, Ruiping; Feng, Jing; Li, Xiaona; Li, Xiyan; Zhang, Hongjie

    2011-01-01

    In this work, a series of electroluminescent (EL) devices based on trivalent europium (Eu3+) complex Eu(TTA)3phen (TTA = thenoyltrifluoroacetone, phen = 1,10-phenanthroline) were fabricated by selecting 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and tris(8-hydroxyquinoline) aluminum (Alq3) as hole block and electron transport materials, respectively. Interestingly, we found the transport of electrons decreases gradually with increasing thicknesses and evaporation rates of BCP and Alq3 layers. Analyzing carrier distribution and EL spectra, we conclude that appropriately modulating the thicknesses and evaporation rates is an efficient way to decrease the accumulation of electrons in HBL, thus suppressing the EL of hole block material. On the other hand, decreasing the transport of electrons can also facilitate the balance of holes and electrons on Eu(TTA)3phen molecules, thus further enhancing the EL efficiency. As a result, pure Eu3+ emission with the efficiency as high as 8.49 cd/A was realized by controlling the thicknesses and evaporation rates of BCP and Alq3 layers to be 30 nm and 0.10 nm/s, 40 nm and 0.10 nm/s, respectively.

  5. Atomizing characteristics of swirl can combustor modules with swirl blast fuel injectors. [in terms of NOX emission rate

    NASA Technical Reports Server (NTRS)

    Ingebo, R. D.

    1980-01-01

    Cold flow atomization tests of several different designs of swirl can combustor modules were conducted in a 7.6 cm diameter duct at airflow rates (per unit area) of 7.3 to 25.7 g/sq cm sec and water flow rates of 6.3 to 18.9 g/sec. The effect of air and water flow rates on the mean drop size of water sprays produced with the swirl blast fuel injectors were determined. Also, from these data it was possible to determine the effect of design modifications on the atomizing performance of various fuel injector and air swirler configurations. The trend in atomizing performance, as based on the mean drop size, was then compared with the trends in the production of nitrogen oxides obtained in combustion studues with the same swirl can combustors. It was found that the fuel injector design that gave the best combustor performance in terms of a low NOx emission index also gave the best atomizing performance as characterized by a spray of relatively small mean drop diameter. It was also demonstrated that at constant inlet air stream momentum the nitrogen oxides emission index was found to vary inversely with the square of the mean drop diameter of the spray produced by the different swirl blast fuel injectors. Test conditions were inlet air static pressures of 100,000 to 200,000 N/sq m at an inlet air temperature of 293 K.

  6. Patterns of cosmogenic radionuclide production rates in the heliosphere and problems of solar modulation on a long time scale

    NASA Astrophysics Data System (ADS)

    Ustinova, G. K.

    2016-11-01

    The results of long-term studies of cosmogenic radionuclide production rates along the orbits of 39 chondrites that fell to the Earth between 1959 and 2013 are presented. They constitute a long series of homogeneous data, a statistical smoothing of which demonstrate some general patterns of the distribution and variations of Galactic cosmic rays (GCRs) with energy >100 MeV in the inner (<5 AU) heliosphere. A correlation analysis of the production rates of radionuclides with different half-lives suggests that the solar GCR modulation mechanism is constant over at least 1 million years. The role of stochastic factors in the polarity reversal of the general solar magnetic field for the phases of maximum solar activity has been revealed. The subtle sensitivity of the 54Mn production rate in the Chelyabinsk chondrite to the short-term closure of the heliosphere for positively charged particles over 14 months between June 2012 and July 2013 is used as an example to show the high resolution of the method of using cosmogenic radionuclides in meteorites as natural GCR detectors.

  7. Evidence that the RdeA protein is a component of a multistep phosphorelay modulating rate of development in Dictyostelium.

    PubMed Central

    Chang, W T; Thomason, P A; Gross, J D; Neweil, P C

    1998-01-01

    We have isolated an insertional mutant of Dictyostelium discoideum that aggregated rapidly and formed spores and stalk cells within 14 h of development instead of the normal 24 h. We have shown by parasexual genetics that the insertion is in the rdeA locus and have cloned the gene. It encodes a predicted 28 kDa protein (RdeA) that is enriched in charged residues and is very hydrophilic. Constructs with the DNA for the c-Myc epitope or for the green fluorescent protein indicate that RdeA is not compartmentalized. RdeA displays homology around a histidine residue at amino acid 65 with members of the H2 module family of phosphotransferases that participate in multistep phosphoryl relays. Replacement of this histidine rendered the protein inactive. The mutant is complemented by transformation with the Ypd1 gene of Saccharomyces cerevisiae, itself an H2 module protein. We propose that RdeA is part of a multistep phosphorelay system that modulates the rate of development. PMID:9582274

  8. Groundwater flow modulation of basal heat budget and melt rates near Dome C, Antarctica

    NASA Astrophysics Data System (ADS)

    Beem, Lucas; Roberts, Jason; Ritz, Catherine; Richter, Tom; Young, Duncan; Kempf, Scott; Cavitte, Marie; Gooch, Brad; Blankenship, Donald

    2017-04-01

    Subglacial thermodynamics impact the evolution of ice sheets through melting/freezing and ice dynamic feedbacks, which may enable or discourage fast flow. An under-considered aspect of the basal heat budget is subglacial groundwater flow. Water flow in basal substrate can advect heat towards or away from the ice base up to an order of magnitude greater than geothermal flux commonly assumed beneath the Antarctic Ice Sheet. We use a three-dimensional steady state groundwater model with a range of hydrological parameters to estimate the effect of groundwater on the basal heat distribution. Near an ice divide, gradients in groundwater pressure primarily depend on basal topography and the applied hydrological parameter field. Model results indicate that topographic highs of the glacier bed generally lose water into the underlying substrate. Conversely, valleys are the location of groundwater discharge and advection of heat towards the glacier bed. We apply this model to a region near Dome C of East Antarctica, to address how groundwater modulation of heat availability at the glacier bed may impact the survivability of basal ice. This question is particularly relevant to the attempts to identify a ice core drilling site to recover ice between 800 kyr to 1.2 Myr in age. Dome C is a candidate for such an ice core site and a dense grid of airborne geophysical survey at this location supplies model boundary conditions from basal topography and ice thickness. In addition, observed gravity and magnetic potential fields constrain possible subglacial substrates and a likely hydrological parameter range. Strongly vertical vectors of water flow, seen in some model configurations, can produce rapid advection of heat indicating that groundwater flow vectors can be a significant indicator of basal ice survivability.

  9. Modulation of the Sympatho-Vagal Balance during Sleep: Frequency Domain Study of Heart Rate Variability and Respiration

    PubMed Central

    Cabiddu, Ramona; Cerutti, Sergio; Viardot, Geoffrey; Werner, Sandra; Bianchi, Anna M.

    2012-01-01

    Sleep is a complex state characterized by important changes in the autonomic modulation of the cardiovascular activity. Heart rate variability (HRV) greatly changes during different sleep stages, showing a predominant parasympathetic drive to the heart during non-rapid eye movement (NREM) sleep and an increased sympathetic activity during rapid eye movement (REM) sleep. Respiration undergoes important modifications as well, becoming deeper and more regular with deep sleep and shallower and more frequent during REM sleep. The aim of the present study is to assess both autonomic cardiac regulation and cardiopulmonary coupling variations during different sleep stages in healthy subjects, using spectral and cross-spectral analysis of the HRV and respiration signals. Polysomnographic sleep recordings were performed in 11 healthy women and the HRV signal and the respiration signal were obtained. The spectral and cross-spectral parameters of the HRV signal and of the respiration signal were computed at low frequency and at breathing frequency (high frequency, HF) during different sleep stages. Results attested a sympatho-vagal balance shift toward parasympathetic modulation during NREM sleep and toward sympathetic modulation during REM sleep. Spectral analysis of the HRV signal and of the respiration signal indicated a higher respiration regularity during deep sleep, and a higher parasympathetic drive was also confirmed by an increase in the coherence between the HRV and the respiration signal in the HF band during NREM sleep. Our findings about sleep stage-dependent variations in the HRV signal and in the respiratory activity are in line with previous evidences and confirm spectral analysis of the HRV and the respiration signal to be a suitable tool for investigating cardiac autonomic modulation and cardio-respiratory coupling during sleep. PMID:22416233

  10. Blazhko effect in the Galactic bulge fundamental mode RR Lyrae stars - I. Incidence rate and differences between modulated and non-modulated stars

    NASA Astrophysics Data System (ADS)

    Prudil, Z.; Skarka, M.

    2017-04-01

    We present the first paper of a series focused on the Blazhko effect in RR Lyrae type stars pulsating in the fundamental mode that are located in the Galactic bulge. A comprehensive overview of the incidence rate and light-curve characteristics of the Blazhko stars is given. We analysed 8282 stars having the best quality data in the OGLE-IV survey, and found that at least 40.3 per cent of the stars show modulation of their light curves. The number of Blazhko stars we identified is 3341, which is the largest sample ever studied, implying that these are the most relevant statistical results currently available. Using combined data sets with OGLE-III observations, we found that 50 per cent of the stars that show unresolved peaks close to the main component in OGLE-IV are actually Blazhko stars with extremely long periods. Blazhko stars with modulation occur preferentially among RR Lyrae stars with shorter pulsation periods in the Galactic bulge. Fourier amplitude and phase coefficients based on the mean light curves appear to be substantially lower for Blazhko stars than for stars with an unmodulated light curve on average. We derived new relations for the compatibility parameter Dm in the I passband and relations that allow for differentiating modulated and non-modulated stars easily based on R31, ϕ21 and ϕ31. Photometric metallicities, intrinsic colours and absolute magnitudes computed using empirical relations are the same for Blazhko and non-modulated stars in the Galactic bulge, suggesting there is no correlation between the occurrence of the Blazhko effect and these parameters.

  11. Rating Movies and Rating the Raters Who Rate Them

    PubMed Central

    Zhou, Hua; Lange, Kenneth

    2010-01-01

    The movie distribution company Netflix has generated considerable buzz in the statistics community by offering a million dollar prize for improvements to its movie rating system. Among the statisticians and computer scientists who have disclosed their techniques, the emphasis has been on machine learning approaches. This article has the modest goal of discussing a simple model for movie rating and other forms of democratic rating. Because the model involves a large number of parameters, it is nontrivial to carry out maximum likelihood estimation. Here we derive a straightforward EM algorithm from the perspective of the more general MM algorithm. The algorithm is capable of finding the global maximum on a likelihood landscape littered with inferior modes. We apply two variants of the model to a dataset from the MovieLens archive and compare their results. Our model identifies quirky raters, redefines the raw rankings, and permits imputation of missing ratings. The model is intended to stimulate discussion and development of better theory rather than to win the prize. It has the added benefit of introducing readers to some of the issues connected with analyzing high-dimensional data. PMID:20802818

  12. Rating Movies and Rating the Raters Who Rate Them.

    PubMed

    Zhou, Hua; Lange, Kenneth

    2009-11-01

    The movie distribution company Netflix has generated considerable buzz in the statistics community by offering a million dollar prize for improvements to its movie rating system. Among the statisticians and computer scientists who have disclosed their techniques, the emphasis has been on machine learning approaches. This article has the modest goal of discussing a simple model for movie rating and other forms of democratic rating. Because the model involves a large number of parameters, it is nontrivial to carry out maximum likelihood estimation. Here we derive a straightforward EM algorithm from the perspective of the more general MM algorithm. The algorithm is capable of finding the global maximum on a likelihood landscape littered with inferior modes. We apply two variants of the model to a dataset from the MovieLens archive and compare their results. Our model identifies quirky raters, redefines the raw rankings, and permits imputation of missing ratings. The model is intended to stimulate discussion and development of better theory rather than to win the prize. It has the added benefit of introducing readers to some of the issues connected with analyzing high-dimensional data.

  13. Insights into the hierarchical structure and digestion rate of alkali-modulated starches with different amylose contents.

    PubMed

    Qiao, Dongling; Yu, Long; Liu, Hongsheng; Zou, Wei; Xie, Fengwei; Simon, George; Petinakis, Eustathios; Shen, Zhiqi; Chen, Ling

    2016-06-25

    Combined analytical techniques were used to explore the effects of alkali treatment on the multi-scale structure and digestion behavior of starches with different amylose/amylopectin ratios. Alkali treatment disrupted the amorphous matrix, and partial lamellae and crystallites, which weakened starch molecular packing and eventually enhanced the susceptibility of starch to alkali. Stronger alkali treatment (0.5% w/w) made this effect more prominent and even transformed the dual-phase digestion of starch into a triple-phase pattern. Compared with high-amylose starch, regular maize starch, which possesses some unique structure characteristics typically as pores and crystallite weak points, showed evident changes of hierarchical structure and in digestion rate. Thus, alkali treatment has been demonstrated as a simple method to modulate starch hierarchical structure and thus to realize the rational development of starch-based food products with desired digestibility.

  14. A specialized layering module for high rep-rate production of free standing HiPER targets

    NASA Astrophysics Data System (ADS)

    Aleksandrova, I.; Belolipetskiy, A.; Koresheva, E.; Koshelev, E.; Malinina, E.; Mitina, L.; Panina, L.; Chtcherbakov, V.; Tolley, M.; Edwards, C.; Spindloe, C.

    2013-11-01

    The target supply system is a necessary requirement for fueling a future energy source (reactor) with a high rep-rate: 0.1-10 Hz. At the Lebedev Physical Institute (LPI), significant progress has been made in the technology based on rapid fuel layering inside moving free-standing targets that is referred to as FST (Free-Standing Targets) layering method. This allows creating a continuously or repeatable operating FST supply system, the development of which at LPI dates back to 1980s. Therefore, the LPI is in the position to propose the use of FST technologies for HiPER facility operation (conceptual design and prototype realization). Here we report on our most significant results on the development of a specialized layering module prototype for repeatable formation of HiPER free-standing cryogenic targets.

  15. In vitro fermentation profiles, gas production rates, and microbiota modulation as affected by certain fructans, galactooligosaccharides, and polydextrose.

    PubMed

    Hernot, David C; Boileau, Thomas W; Bauer, Laura L; Middelbos, Ingmar S; Murphy, Michael R; Swanson, Kelly S; Fahey, George C

    2009-02-25

    It is of interest to benefit from the positive intestinal health outcomes of prebiotic consumption but with minimal gas production. This study examined gas production potential, fermentation profile, and microbial modulation properties of several types of oligosaccharides. Substrates studied included short-chain, medium-chain, and long-chain fructooligosaccharides, oligofructose-enriched inulin, galactooligosaccharide, and polydextrose. Each substrate was fermented in vitro using human fecal inoculum, and fermentation characteristics were quantified at 0, 4, 8, and 12 h. Gas and short-chain fatty acid (SCFA) production data showed that short-chain oligosaccharides were more rapidly fermented and produced more SCFA and gas than substrates with greater degrees of polymerization. Lactobacilli increased similarly among substrates. Short-chain oligosaccharides fermentation resulted in the greatest increase in bifidobacteria concentrations. Mixing short- and long-chain oligosaccharides attenuated short-chain oligosaccharide fermentation rate and extent. This study provides new information on the fermentation characteristics of some oligosaccharides used in human nutrition.

  16. Average symbol error rate for M-ary quadrature amplitude modulation in generalized atmospheric turbulence and misalignment errors

    NASA Astrophysics Data System (ADS)

    Sharma, Prabhat Kumar

    2016-11-01

    A framework is presented for the analysis of average symbol error rate (SER) for M-ary quadrature amplitude modulation in a free-space optical communication system. The standard probability density function (PDF)-based approach is extended to evaluate the average SER by representing the Q-function through its Meijer's G-function equivalent. Specifically, a converging power series expression for the average SER is derived considering the zero-boresight misalignment errors in the receiver side. The analysis presented here assumes a unified expression for the PDF of channel coefficient which incorporates the M-distributed atmospheric turbulence and Rayleigh-distributed radial displacement for the misalignment errors. The analytical results are compared with the results obtained using Q-function approximation. Further, the presented results are supported by the Monte Carlo simulations.

  17. Modulation of lead-induced performance deficit in children by varying signal rate in a serial choice reaction task

    SciTech Connect

    Winneke, G.; Brockhaus, A.; Collet, W.; Kraemer, U. )

    1989-11-01

    Evidence is presented showing that serial choice reaction performance is disrupted at low blood lead levels (PbB), and that parametric variation of task characteristics modulates the degree of disruption. This evidence is based on two independent studies in 6- to 9-year-old children living in two lead smelter areas in the cities of Nordenham (N = 114) and Stolberg (N = 109) in West Germany. Average PbB was 8.2 micrograms/100 ml (4.4-23.8 micrograms/100 ml) in the Nordenham sample and 7.4 micrograms/100 ml (4.2-18.0 micrograms/100 ml) in the Stolberg sample. Serial choice reaction performance was assessed by means of the Vienna reaction device in which a random sequence of light and tone signals has to be answered by pressing appropriate response buttons. Correct (hits) and false responses (errors) were evaluated as performance measures, and signal rate was varied in order to achieve easy and difficult task conditions. Exposure-related performance deficit was more pronounced for errors than for hits, more clearcut for high than for low signal rates, and proved significant in both studies after correction for confounding using confounder models of different complexities. Some features of the observed deficit resemble clinical observations in children presenting with attention deficit disorder.

  18. Grapevine Rootstocks Differentially Affect the Rate of Ripening and Modulate Auxin-Related Genes in Cabernet Sauvignon Berries

    PubMed Central

    Corso, Massimiliano; Vannozzi, Alessandro; Ziliotto, Fiorenza; Zouine, Mohamed; Maza, Elie; Nicolato, Tommaso; Vitulo, Nicola; Meggio, Franco; Valle, Giorgio; Bouzayen, Mondher; Müller, Maren; Munné-Bosch, Sergi; Lucchin, Margherita; Bonghi, Claudio

    2016-01-01

    In modern viticulture, grafting commercial grapevine varieties on interspecific rootstocks is a common practice required for conferring resistance to many biotic and abiotic stresses. Nevertheless, the use of rootstocks to gain these essential traits is also known to impact grape berry development and quality, although the underlying mechanisms are still poorly understood. In grape berries, the onset of ripening (véraison) is regulated by a complex network of mobile signals including hormones such as auxins, ethylene, abscisic acid, and brassinosteroids. Recently, a new rootstock, designated M4, was selected based on its enhanced tolerance to water stress and medium vigor. This study investigates the effect of M4 on Cabernet Sauvignon (CS) berry development in comparison to the commercial 1103P rootstock. Physical and biochemical parameters showed that the ripening rate of CS berries is faster when grafted onto M4. A multifactorial analysis performed on mRNA-Seq data obtained from skin and pulp of berries grown in both graft combinations revealed that genes controlling auxin action (ARF and Aux/IAA) represent one of main categories affected by the rootstock genotype. Considering that the level of auxin tightly regulates the transcription of these genes, we investigated the behavior of the main gene families involved in auxin biosynthesis and conjugation. Molecular and biochemical analyses confirmed a link between the rate of berry development and the modulation of auxin metabolism. Moreover, the data indicate that this phenomenon appears to be particularly pronounced in skin tissue in comparison to the flesh. PMID:26904046

  19. Grapevine Rootstocks Differentially Affect the Rate of Ripening and Modulate Auxin-Related Genes in Cabernet Sauvignon Berries.

    PubMed

    Corso, Massimiliano; Vannozzi, Alessandro; Ziliotto, Fiorenza; Zouine, Mohamed; Maza, Elie; Nicolato, Tommaso; Vitulo, Nicola; Meggio, Franco; Valle, Giorgio; Bouzayen, Mondher; Müller, Maren; Munné-Bosch, Sergi; Lucchin, Margherita; Bonghi, Claudio

    2016-01-01

    In modern viticulture, grafting commercial grapevine varieties on interspecific rootstocks is a common practice required for conferring resistance to many biotic and abiotic stresses. Nevertheless, the use of rootstocks to gain these essential traits is also known to impact grape berry development and quality, although the underlying mechanisms are still poorly understood. In grape berries, the onset of ripening (véraison) is regulated by a complex network of mobile signals including hormones such as auxins, ethylene, abscisic acid, and brassinosteroids. Recently, a new rootstock, designated M4, was selected based on its enhanced tolerance to water stress and medium vigor. This study investigates the effect of M4 on Cabernet Sauvignon (CS) berry development in comparison to the commercial 1103P rootstock. Physical and biochemical parameters showed that the ripening rate of CS berries is faster when grafted onto M4. A multifactorial analysis performed on mRNA-Seq data obtained from skin and pulp of berries grown in both graft combinations revealed that genes controlling auxin action (ARF and Aux/IAA) represent one of main categories affected by the rootstock genotype. Considering that the level of auxin tightly regulates the transcription of these genes, we investigated the behavior of the main gene families involved in auxin biosynthesis and conjugation. Molecular and biochemical analyses confirmed a link between the rate of berry development and the modulation of auxin metabolism. Moreover, the data indicate that this phenomenon appears to be particularly pronounced in skin tissue in comparison to the flesh.

  20. Modulation of the rate of cardiac muscle contraction by troponin C constructs with various calcium binding affinities.

    PubMed

    Norman, Catalina; Rall, Jack A; Tikunova, Svetlana B; Davis, Jonathan P

    2007-10-01

    We investigated whether changing thin filament Ca(2+) sensitivity alters the rate of contraction, either during normal cross-bridge cycling or when cross-bridge cycling is increased by inorganic phosphate (P(i)). We increased or decreased Ca(2+) sensitivity of force production by incorporating into rat skinned cardiac trabeculae the troponin C (TnC) mutants V44QTnC(F27W) and F20QTnC(F27W). The rate of isometric contraction was assessed as the rate of force redevelopment (k(tr)) after a rapid release and restretch to the original length of the muscle. Both in the absence of added P(i) and in the presence of 2.5 mM added P(i) 1) Ca(2+) sensitivity of k(tr) was increased by V44QTnC(F27W) and decreased by F20QTnC(F27W) compared with control TnC(F27W); 2) k(tr) at submaximal Ca(2+) activation was significantly faster for V44QTnC(F27W) and slower for F20QTnC(F27W) compared with control TnC(F27W); 3) at maximum Ca(2+) activation, k(tr) values were similar for control TnC(F27W), V44QTnC(F27W), and F20QTnC(F27W); and 4) k(tr) exhibited a linear dependence on force that was indistinguishable for all TnCs. In the presence of 2.5 mM P(i), k(tr) was faster at all pCa values compared with the values for no added P(i) for TnC(F27W), V44QTnC(F27W), and F20QTnC(F27W). This study suggests that TnC Ca(2+) binding properties modulate the rate of cardiac muscle contraction at submaximal levels of Ca(2+) activation. This result has physiological relevance considering that, on a beat-to-beat basis, the heart contracts at submaximal Ca(2+) activation.

  1. The rating reliability calculator

    PubMed Central

    Solomon, David J

    2004-01-01

    Background Rating scales form an important means of gathering evaluation data. Since important decisions are often based on these evaluations, determining the reliability of rating data can be critical. Most commonly used methods of estimating reliability require a complete set of ratings i.e. every subject being rated must be rated by each judge. Over fifty years ago Ebel described an algorithm for estimating the reliability of ratings based on incomplete data. While his article has been widely cited over the years, software based on the algorithm is not readily available. This paper describes an easy-to-use Web-based utility for estimating the reliability of ratings based on incomplete data using Ebel's algorithm. Methods The program is available public use on our server and the source code is freely available under GNU General Public License. The utility is written in PHP, a common open source imbedded scripting language. The rating data can be entered in a convenient format on the user's personal computer that the program will upload to the server for calculating the reliability and other statistics describing the ratings. Results When the program is run it displays the reliability, number of subject rated, harmonic mean number of judges rating each subject, the mean and standard deviation of the averaged ratings per subject. The program also displays the mean, standard deviation and number of ratings for each subject rated. Additionally the program will estimate the reliability of an average of a number of ratings for each subject via the Spearman-Brown prophecy formula. Conclusion This simple web-based program provides a convenient means of estimating the reliability of rating data without the need to conduct special studies in order to provide complete rating data. I would welcome other researchers revising and enhancing the program. PMID:15117416

  2. Fertility Clinic Success Rates

    MedlinePlus

    ... Defects ART and Autism 2013 Assisted Reproductive Technology Fertility Clinic Success Rates Report Recommend on Facebook Tweet Share Compartir 2013 ART Fertility Clinic Success Rates Report [PDF - 1MB] Bookmarks and thumbnails are available ...

  3. THE NORMATIVE INTEREST RATE

    DTIC Science & Technology

    The normative interest rate is defined as the discount rate the government ought to use in making its investment decisions. In the following sections...various alternative ways of setting the level of the normative interest rate are examined. The return on the marginal private investment, the...national time preference, and the long-term interest rate at which the government can borrow are all rejected on the basis that they are merely adaptive to

  4. Effect of combined variation of force amplitude and rate of force development on the modulation characteristics of muscle activation during rapid isometric aiming force production.

    PubMed

    Park, Jin-Hoon; Stelmach, George E

    2006-01-01

    Studies of rapid target-directed limb movements have suggested that various control schemes can be defined by the modulation pattern of the muscle activity. The present study was aimed to address the question regarding the extent to which a simultaneous control of force amplitude, and rate of force development influences the modulation characteristics of muscle activation associated with producing rapid isometric aiming forces at the elbow joint. The subjects were instructed to produce rapid isometric force pulses to three different force amplitudes (15, 35, and 55% of their maximal voluntary contractions) under systematically varied force-rate conditions ranging from a fast and accurate force-rate to the fastest force-rate possible. The results showed that larger force amplitudes were achieved by increasing the rate of force development (d F/d t) while the time to peak force remained relatively constant. The magnitude of the electromyographic (EMG) burst systematically increased as a function of force amplitude at all force-rate conditions. The primary finding was that the characteristic of the EMG burst duration associated with different force amplitudes showed a significant difference among force-rate conditions. Under a fast and accurate force-rate condition, the duration of the agonist burst increased linearly with force amplitude. A gradual transition into a fixed duration of the agonist burst then was observed over the remaining three force-rate requirements. With increasingly faster force-rates, there were no changes in the agonist burst duration over three force amplitudes. These results indicate that the combined variations in force amplitude and force-rate examined relative to the most rapid force-rate influence the control patterns for the muscle activation during the fast isometric force production. Changes in the EMG modulation patterns observed are likely due to the constraints imposed by muscle contractile properties.

  5. Rating Variable Performance.

    ERIC Educational Resources Information Center

    Steiner, Dirk D.; Rain, Jeffrey S.

    Many empirical studies have examined factors that influence ratings of performance. This study examined the rating variable performance of a single individual. Serial position of a single poor or good performance in a series of otherwise good or poor performances was manipulated to examine its effects on both ratings and recommended actions toward…

  6. Handbook of noise ratings

    NASA Technical Reports Server (NTRS)

    Pearsons, K. S.; Bennett, R. L.

    1974-01-01

    The handbook was compiled to provide information in a concise form, describing the multitude of noise rating schemes. It is hoped that by describing the noise rating methods in a single volume the user will have better access to the definitions, application and calculation procedures of the current noise rating methods.

  7. SU-E-T-185: Feasibility Study of Dose Rate Modulated Arc Therapy (DrMAT) for Lung SBRT

    SciTech Connect

    KO, Y; Cho, B; Yi, B; Kwak, J; Song, S; Je, H; Ahn, S; Noh, Y

    2014-06-01

    Purpose: To show the feasibility of clinical application of DrMAT for SBRT in lung cancer patients. DrMAT is a form of dynamic conformal arc therapy where MLC segments and dose rates are controlled through simple field weight optimization. Methods: To show feasibility a new treatment plan was created based on the CT of SBRT lung cancer patients. Static plans with 33 fields are made, which have 11deg in between each field and are acquired rotating gantry angle from 180deg to 188deg in CCW direction, total 352deg is rotated. MLC maintained static aperture for each field. To optimize 33 individual fields, field weight was adjusted accordingly using weight optimization algorithm. Keeping weights and MU of static plan, static MLC aperture was converted to multiple arc segments. Arc plan could be created with the fields in the intervals of 11deg. Static MLC should be converted to arc segment MLC. Dynamic conformal arc therapy plan consists of 33 arc fields, is converted to one dose rate modulated arc therapy (DrMAT) plan. DrMAT plan consists of 166 control points which becomes a single arc plan that changes the shape of MLC for every 2.2deg. The resulting DrMAT plan is not an inverse plan it is a simple form of dynamic conformal arc plan using field weight obtained from static plan. This is compared and evaluated with the VMAT plan. Results: DrMAT and VMAT plans have been compared based on the RTOG1021. Both DrMAT and VMAT plans satisfy 100% irradiation to 95% of PTV and critical organs did not exceed dose limit suggested in RTOG1021. DrMAT plan is almost similar with VMAT plan in Result. Conclusion: Field weight optimization method did not show better Resultcompared to VMAT optimization. However, considering simplicity, DrMAT satisfies the condition in RTOG1021. Therefore clinical application of DrMAT is feasible.

  8. Modulation by stimulation rate of basal and cAMP-elevated Ca2+ channel current in guinea pig ventricular cardiomyocytes

    PubMed Central

    1995-01-01

    The modulation of L-type Ca2+ current (ICa) by changes in stimulation frequency was investigated in single ventricular cardiomyocytes isolated from guinea pig hearts. Electrical recordings were carried out at 21-25 degrees C and at 33-37 degrees C with the whole-cell patch clamp method, under K(+)-free conditions. A comparison is made between the response to frequency changes for ICa in the basal state and after the application of drugs which elevate the level of adenosine-3',5'- cyclic monophosphate (cAMP) within the cells. Peak basal ICa was reduced with an increase in stimulation rate from 0.5 Hz to 1, 2, 3, 4, or 5 Hz. This frequency-induced reduction of ICa was enhanced by reduced temperature, was unchanged when Na+ or Ba2+ carried the basal Ca2+ channel current, and was greatly enhanced after elevating cAMP levels with forskolin, isoprenaline, or 8-(4-chlorophenylthio)-cyclic AMP. We examined the mechanism of the enhancement of the frequency- induced reduction of ICa by cAMP, and found two conditions which abolished it: (a) application of isoprenaline when Na+ carried the Ca2+ channel current in Ca(2+)-free solution, or (b) application of 3- isobutyl-1-methylxanthine, a broad-spectrum phosphodiesterase inhibitor. It was further shown that an elevation of both ICa and cAMP (induced by isoprenaline), and not an increase of ICa alone (induced by Bay K 8644), is required to produce the extra component of reduction by frequency. It is concluded that Ca2+ entry results in feedback regulation of ICa, through the activation of Ca(2+)-dependent phosphodiesterase(s). This is important in the context of sympathetic stimulation, which produces the companion conditions of an elevated heart rate and increases in cAMP levels and Ca2+ entry. PMID:8537815

  9. Elucidating PID Degradation Mechanisms and In Situ Dark I–V Monitoring for Modeling Degradation Rate in CdTe Thin-Film Modules

    SciTech Connect

    Hacke, Peter; Spataru, Sergiu; Johnston, Steve; Terwilliger, Kent; VanSant, Kaitlyn; Kempe, Michael; Wohlgemuth, John; Kurtz, Sarah; Olsson, Anders; Propst, Michelle

    2016-11-01

    A progression of potential-induced degradation (PID) mechanisms are observed in CdTe modules, including shunting/junction degradation and two different manifestations of series resistance depending on the stress level and water ingress. The dark I-V method for in-situ characterization of Pmax based on superposition was adapted for the thin-film modules undergoing PID in view of the degradation mechanisms observed. An exponential model based on module temperature and relative humidity was fit to the PID rate for multiple stress levels in chamber tests and validated by predicting the observed degradation of the module type in the field.

  10. Can geometric indices of heart rate variability predict improvement in autonomic modulation after resistance training in chronic obstructive pulmonary disease?

    PubMed

    Santos, Ana Alice Soares Dos; Ricci-Vitor, Ana Laura; Bragatto, Vanessa Santa Rosa; Santos, Ana Paula Soares Dos; Ramos, Ercy Mara Cipulo; Vanderlei, Luiz Carlos Marques

    2017-03-01

    Chronic obstructive pulmonary disease (COPD) is associated with autonomic dysfunctions that can be evaluated through heart rate variability (HRV). Resistance training promotes improvement in autonomic modulation; however, studies that evaluate this scenario using geometric indices, which include nonlinear evaluation, thus providing more accurate information for physiological interpretation of HRV, are unknown. This study aimed to investigate the influence of resistance training on autonomic modulation, using geometric indices of HRV, and peripheral muscle strength in individuals with COPD. Fourteen volunteers with COPD were submitted to resistance training consisting of 24 sessions lasting 60 min each, with a frequency of three times a week. The intensity was determined as 60% of one maximum repetition and was progressively increased until 80% for the upper and lower limbs. The HRV and dynamometry were performed at two moments, the beginning and the end of the experimental protocol. Significant increases were observed in the RRtri (4·81 ± 1·60 versus 6·55 ± 2·69, P = 0·033), TINN (65·36 ± 35·49 versus 101·07 ± 63·34, P = 0·028), SD1 (7·48 ± 3·17 versus 11·04 ± 6·45, P = 0·038) and SD2 (22·30 ± 8·56 versus 32·92 ± 18·78, P = 0·022) indices after the resistance training. Visual analysis of the Poincare plot demonstrated greater dispersion beat-to-beat and in the long-term interval between consecutive heart beats. Regarding muscle strength, there was a significant increase in the shoulder abduction and knee flexion. In conclusion, geometric indices of HRV can predict improvement in autonomic modulation after resistance training in individuals with COPD; improvement in peripheral muscle strength in patients with COPD was also observed.

  11. Rate theories for biologists

    PubMed Central

    Zhou, Huan-Xiang

    2012-01-01

    Some of the rate theories that are most useful for modeling biological processes are reviewed. By delving into some of the details and subtleties in the development of the theories, the review will hopefully help the reader gain a more than superficial perspective. Examples are presented to illustrate how rate theories can be used to generate insight at the microscopic level into biomolecular behaviors. Attempt is made to clear up a number of misconceptions in the literature regarding popular rate theories, including the appearance of Planck’s constant in the transition-state theory and the Smoluchowski result as an upper limit for protein-protein and protein-DNA association rate constants. Future work in combining the implementation of rate theories through computer simulations with experimental probes of rate processes, and in modeling effects of intracellular environments so theories can be used for generating rate constants for systems biology studies is particularly exciting. PMID:20691138

  12. Rate theories for biologists.

    PubMed

    Zhou, Huan-Xiang

    2010-05-01

    Some of the rate theories that are most useful for modeling biological processes are reviewed. By delving into some of the details and subtleties in the development of the theories, the review will hopefully help the reader gain a more than superficial perspective. Examples are presented to illustrate how rate theories can be used to generate insight at the microscopic level into biomolecular behaviors. An attempt is made to clear up a number of misconceptions in the literature regarding popular rate theories, including the appearance of Planck's constant in the transition-state theory and the Smoluchowski result as an upper limit for protein-protein and protein-DNA association rate constants. Future work in combining the implementation of rate theories through computer simulations with experimental probes of rate processes, and in modeling effects of intracellular environments so that theories can be used for generating rate constants for systems biology studies is particularly exciting.

  13. Modulation of heart rate response to acute stressors throughout the breeding season in the king penguin Aptenodytes patagonicus.

    PubMed

    Viblanc, Vincent A; Smith, Andrew D; Gineste, Benoit; Kauffmann, Marion; Groscolas, René

    2015-06-01

    'Fight-or-flight' stress responses allow animals to cope adaptively to sudden threats by mobilizing energy resources and priming the body for action. Because such responses can be costly and redirect behavior and energy from reproduction to survival, they are likely to be shaped by specific life-history stages, depending on the available energy resources and the commitment to reproduction. Here, we consider how heart rate (HR) responses to acute stressors are affected by the advancing breeding season in a colonial seabird, the king penguin (Aptenodytes patagonicus). We subjected 77 birds (44 males, 33 females) at various stages of incubation and chick-rearing to three experimental stressors (metal sound, distant approach and capture) known to vary both in their intensity and associated risk, and monitored their HR responses. Our results show that HR increase in response to acute stressors was progressively attenuated with the stage of breeding from incubation to chick-rearing. Stress responses did not vary according to nutritional status or seasonal timing (whether breeding was initiated early or late in the season), but were markedly lower during chick-rearing than during incubation. This pattern was obvious for all three stressors. We discuss how 'fight-or-flight' responses may be modulated by considering the energy commitment to breeding, nutritional status and reproductive value of the brood in breeding seabirds. © 2015. Published by The Company of Biologists Ltd.

  14. Improved crystalline quality of N-polar GaN epitaxial layers grown with reformed flow-rate-modulation technology

    NASA Astrophysics Data System (ADS)

    Zhang, Heng; Zhang, Xiong; Wang, Shuchang; Wang, Xiaolei; Zhao, Jianguo; Wu, Zili; Dai, Qian; Yang, Hongquan; Cui, Yiping

    2017-01-01

    A reformed flow-rate-modulation technology was developed for the metalorganic vapor phase epitaxy (MOVPE) growth of the N-polar GaN epitaxial layers. To improve the crystalline quality of the N-polar GaN epitaxial layers, a GaN nucleation layer was grown at relatively low temperature with carefully-controlled pulsed supply of Ga source and showed diverse morphology with atomic force microscope (AFM). Furthermore, the electrical and optical properties of the grown N-polar GaN epitaxial layers were investigated extensively by means of Hall effect, photoluminescence (PL), and X-ray rocking curve (XRC) measurements. The characterization results revealed that as compared with the N-polar GaN epitaxial layer grown over the conventional GaN nucleation layer which was deposited with continuous supply of both N and Ga sources, the electrical and optical properties of the N-polar GaN epitaxial layer grown with optimized supply of Ga source for the GaN nucleation layer were significantly improved.

  15. Packet error rate analysis of digital pulse interval modulation in intersatellite optical communication systems with diversified wavefront deformation.

    PubMed

    Zhu, Jin; Wang, Dayan; Xie, Wanqing

    2015-02-20

    Diversified wavefront deformation is an inevitable phenomenon in intersatellite optical communication systems, which will decrease system performance. In this paper, we investigate the description of wavefront deformation and its influence on the packet error rate (PER) of digital pulse interval modulation (DPIM). With the wavelet method, the diversified wavefront deformation can be described by wavelet parameters: coefficient, dilation, and shift factors, where the coefficient factor represents the depth, dilation factor represents the area, and shift factor is for location. Based on this, the relationship between PER and wavelet parameters is analyzed from a theoretical viewpoint. Numerical results illustrate the validity of theoretical analysis: PER increases with the depth and area and decreases if location gets farther from the center of the optical antenna. In addition to describing diversified deformation, the advantage of the wavelet method over Zernike polynomials in computational complexity is shown via numerical example. This work provides a feasible method for the description along with influence analysis of diversified wavefront deformation from a practical viewpoint and will be helpful for designing optical systems.

  16. Time Modulation of the K-Shell Electron Capture Decay Rates of H-like Heavy Ions at GSI Experiments

    SciTech Connect

    Ivanov, A. N.; Kienle, P.

    2009-08-07

    According to experimental data at GSI, the rates of the number of daughter ions, produced by the nuclear K shell electron capture decays of the H-like heavy ions with one electron in the K shell, such as {sup 140}Pr{sup 58+}, {sup 142}Pm{sup 60+}, and {sup 122}I{sup 52+}, are modulated in time with periods T{sub EC} of the order of a few seconds, obeying an A scaling T{sub EC}=A/20 s, where A is the mass number of the mother nuclei, and with amplitudes a{sub d}{sup EC}approx0.21. We show that these data can be explained in terms of the interference of two massive neutrino mass eigenstates. The appearance of the interference term is due to overlap of massive neutrino mass eigenstate energies and of the wave functions of the daughter ions in two-body decay channels, caused by the energy and momentum uncertainties introduced by time differential detection of the daughter ions in GSI experiments.

  17. Multi-rate demodulator architecture

    NASA Technical Reports Server (NTRS)

    Sherry, Michael A.; Caso, Gregory S.

    1991-01-01

    A unique digital multi-rate demodulator (MRD) architecture is presented for onboard satellite communications processing. The multi-rate feature enables the same demodulator hardware to process either one wideband channel (WBC), or process up to thirty-two independent narrowband channels (NBC) that are time division multiplexed (TDM). The MRD can process many quadrature modulation format such as offset quadrature phase shift keying (OQPSK). Possible applications include voice and data transmission for commercial or military users.

  18. Multi-rate demodulator architecture

    NASA Astrophysics Data System (ADS)

    Sherry, Michael A.; Caso, Gregory S.

    1991-11-01

    A unique digital multi-rate demodulator (MRD) architecture is presented for onboard satellite communications processing. The multi-rate feature enables the same demodulator hardware to process either one wideband channel (WBC), or process up to thirty-two independent narrowband channels (NBC) that are time division multiplexed (TDM). The MRD can process many quadrature modulation format such as offset quadrature phase shift keying (OQPSK). Possible applications include voice and data transmission for commercial or military users.

  19. Measuring zebrafish turning rate.

    PubMed

    Mwaffo, Violet; Butail, Sachit; di Bernardo, Mario; Porfiri, Maurizio

    2015-06-01

    Zebrafish is becoming a popular animal model in preclinical research, and zebrafish turning rate has been proposed for the analysis of activity in several domains. The turning rate is often estimated from the trajectory of the fish centroid that is output by commercial or custom-made target tracking software run on overhead videos of fish swimming. However, the accuracy of such indirect methods with respect to the turning rate associated with changes in heading during zebrafish locomotion is largely untested. Here, we compare two indirect methods for the turning rate estimation using the centroid velocity or position data, with full shape tracking for three different video sampling rates. We use tracking data from the overhead video recorded at 60, 30, and 15 frames per second of zebrafish swimming in a shallow water tank. Statistical comparisons of absolute turning rate across methods and sampling rates indicate that, while indirect methods are indistinguishable from full shape tracking, the video sampling rate significantly influences the turning rate measurement. The results of this study can aid in the selection of the video capture frame rate, an experimental design parameter in zebrafish behavioral experiments where activity is an important measure.

  20. Method of joint bit rate/modulation format identification and optical performance monitoring using asynchronous delay-tap sampling for radio-over-fiber systems

    NASA Astrophysics Data System (ADS)

    Guesmi, Latifa; Menif, Mourad

    2016-08-01

    In the context of carrying a wide variety of modulation formats and data rates for home networks, the study covers the radio-over-fiber (RoF) technology, where the need for an alternative way of management, automated fault diagnosis, and formats identification is expressed. Also, RoF signals in an optical link are impaired by various linear and nonlinear effects including chromatic dispersion, polarization mode dispersion, amplified spontaneous emission noise, and so on. Hence, for this purpose, we investigated the sampling method based on asynchronous delay-tap sampling in conjunction with a cross-correlation function for the joint bit rate/modulation format identification and optical performance monitoring. Three modulation formats with different data rates are used to demonstrate the validity of this technique, where the identification accuracy and the monitoring ranges reached high values.

  1. Observed Barium Emission Rates

    NASA Technical Reports Server (NTRS)

    Stenbaek-Nielsen, H. C.; Wescott, E. M.; Hallinan, T. J.

    1993-01-01

    The barium releases from the CRRES satellite have provided an opportunity for verifying theoretically calculated barium ion and neutral emission rates. Spectra of the five Caribbean releases in the summer of 1991 were taken with a spectrograph on board a U.S. Air Force jet aircraft. Because the line of sight release densities are not known, only relative rates could be obtained. The observed relative rates agree well with the theoretically calculated rates and, together with other observations, confirm the earlier detailed theoretical emission rates. The calculated emission rates can thus with good accuracy be used with photometric observations. It has been postulated that charge exchange between neutral barium and oxygen ions represents a significant source for ionization. If so. it should be associated with emissions at 4957.15 A and 5013.00 A, but these emissions were not detected.

  2. Rate of tension redevelopment is not modulated by sarcomere length in permeabilized human, murine, and porcine cardiomyocytes.

    PubMed

    Edes, István Ferenc; Czuriga, Dániel; Csányi, Gábor; Chlopicki, Stefan; Recchia, Fabio A; Borbély, Attila; Galajda, Zoltán; Edes, István; van der Velden, Jolanda; Stienen, Ger J M; Papp, Zoltán

    2007-07-01

    The increase in Ca(2+) sensitivity of isometric force development along with sarcomere length (SL) is considered as the basis of the Frank-Starling law of the heart, possibly involving the regulation of cross-bridge turnover kinetics. Therefore, the Ca(2+) dependencies of isometric force production and of the cross-bridge-sensitive rate constant of force redevelopment (k(tr)) were determined at different SLs (1.9 and 2.3 mum) in isolated human, murine, and porcine permeabilized cardiomyocytes. k(tr) was also determined in the presence of 10 mM inorganic phosphate (P(i)), which interfered with the force-generating cross-bridge transitions. The increases in Ca(2+) sensitivities of force with SL were very similar in human, murine, and porcine cardiomyocytes (DeltapCa(50): approximately 0.11). k(tr) was higher (P < 0.05) in mice than in humans or pigs at all Ca(2+) concentrations ([Ca(2+)]) [maximum k(tr) (k(tr,max)) at a SL of 1.9 mum and pCa 4.75: 1.33 +/- 0.11, 7.44 +/- 0.15, and 1.02 +/- 0.05 s(-1), in humans, mice, and pigs, respectively] but k(tr) did not depend on SL in any species. Moreover, when the k(tr) values for each species were expressed relative to their respective maxima, similar Ca(2+) dependencies were obtained. Ten millimolar P(i) decreased force to approximately 60-65% and left DeltapCa(50) unaltered in all three species. P(i) increased k(tr,max) by a factor of approximately 1.6 in humans and pigs and by a factor of approximately 3 in mice, independent of SL. In conclusion, species differences exert a major influence on k(tr), but SL does not appear to modulate the cross-bridge turnover rates in human, murine, and porcine hearts.

  3. Utility of a Novel Biofeedback Device for Within-Breath Modulation of Heart Rate in Rats: A Quantitative Comparison of Vagus Nerve vs. Right Atrial Pacing

    PubMed Central

    O'Callaghan, Erin L.; Chauhan, Ashok S.; Zhao, Le; Lataro, Renata M.; Salgado, Helio C.; Nogaret, Alain; Paton, Julian F. R.

    2016-01-01

    In an emerging bioelectronics era, there is a clinical need for physiological devices incorporating biofeedback that permits natural and demand-dependent control in real time. Here, we describe a novel device termed a central pattern generator (CPG) that uses cutting edge analog circuitry producing temporally controlled, electrical stimulus outputs based on the real time integration of physiological feedback. Motivated by the fact that respiratory sinus arrhythmia (RSA), which is the cyclical changes in heart rate every breath, is an essential component of heart rate variability (HRV) (an indicator of cardiac health), we have explored the versatility and efficiency of the CPG for producing respiratory modulation of heart rate in anesthetized, spontaneously breathing rats. Diaphragmatic electromyographic activity was used as the input to the device and its output connected to either the right cervical vagus nerve or the right atrium for pacing heart rate. We found that the CPG could induce respiratory related heart rate modulation that closely mimicked RSA. Whether connected to the vagus nerve or right atrium, the versatility of the device was demonstrated by permitting: (i) heart rate modulation in any phase of the respiratory cycle, (ii) control of the magnitude of heart rate modulation, and (iii) instant adaptation to changes in respiratory frequency. Vagal nerve pacing was only possible following transection of the nerve limiting its effective use chronically. Pacing via the right atrium permitted better flexibility and control of heart rate above its intrinsic level. This investigation now lays the foundation for future studies using this biofeedback technology permitting closer analysis of both the function and dysfunction of RSA. PMID:26869940

  4. PhoU Allows Rapid Adaptation to High Phosphate Concentrations by Modulating PstSCAB Transport Rate in Sinorhizobium meliloti.

    PubMed

    diCenzo, George C; Sharthiya, Harsh; Nanda, Anish; Zamani, Maryam; Finan, Turlough M

    2017-09-15

    Maintenance of cellular phosphate homeostasis is essential for cellular life. The PhoU protein has emerged as a key regulator of this process in bacteria, and it is suggested to modulate phosphate import by PstSCAB and control activation of the phosphate limitation response by the PhoR-PhoB two-component system. However, a proper understanding of PhoU has remained elusive due to numerous complications of mutating phoU, including loss of viability and the genetic instability of the mutants. Here, we developed two sets of strains of Sinorhizobium meliloti that overcame these limitations and allowed a more detailed and comprehensive analysis of the biological and molecular activities of PhoU. The data showed that phoU cannot be deleted in the presence of phosphate unless PstSCAB is inactivated also. However, phoU deletions were readily recovered in phosphate-free media, and characterization of these mutants revealed that addition of phosphate to the environment resulted in toxic levels of PstSCAB-mediated phosphate accumulation. Phosphate uptake experiments indicated that PhoU significantly decreased the PstSCAB transport rate specifically in phosphate-replete cells but not in phosphate-starved cells and that PhoU could rapidly respond to elevated environmental phosphate concentrations and decrease the PstSCAB transport rate. Site-directed mutagenesis results suggested that the ability of PhoU to respond to phosphate levels was independent of the conformation of the PstSCAB transporter. Additionally, PhoU-PhoU and PhoU-PhoR interactions were detected using a bacterial two-hybrid screen. We propose that PhoU modulates PstSCAB and PhoR-PhoB in response to local, internal fluctuations in phosphate concentrations resulting from PstSCAB-mediated phosphate import.IMPORTANCE Correct maintenance of cellular phosphate homeostasis is critical in all kingdoms of life and in bacteria involves the PhoU protein. This work provides novel insights into the role of the Sinorhizobium

  5. Effects of walking on heart rate recovery, endothelium modulators and quality of life in patients with heart failure.

    PubMed

    Tsarouhas, Konstantinos; Karatzaferi, Christina; Tsitsimpikou, Christina; Haliassos, Alexander; Kouretas, Demetrios; Pavlidis, Pavlos; Veskoukis, Aristidis; Adamopoulos, Stamatis; Kyriakides, Zenon; Constantinou, Louis; Koutedakis, Yannis; Rentoukas, Elias

    2011-08-01

    Few studies have addressed the impact of moderate unsupervised everyday physical activity in patients with chronic heart failure (CHF). We investigated the effects of a 12-week walking programme as the sole exercise intervention on heart rate recovery (HRR), index of the autonomic system equilibrium, serum modulators of endothelial function (i.e. asymmetric dimethylarginine (ADMA) and homocysteine), markers of inflammation and oxidative stress and quality of life measures (i.e. SF-36 and the Zung depression scale) in CHF patients. Twenty-eight stabilized CHF patients of ΝYHΑ class II and III volunteered to participate either in the exercise (n = 18) or in the non-exercise (n = 10) groups. Ten age-matched healthy volunteers provided reference values. The exercise programme consisted of unsupervised 40-minute walking for five days per week. Repeated measures ANOVA revealed significant improvements in HRR (p < 0.001) in the exercise patients compared to their non-exercise counterparts. ADMA levels in CHF patients at baseline were found higher than the healthy reference volunteers (p < 0.03), while a decrease in ADMA levels after walking was associated with HRR changes (r = 0.74, p = 0.007). Homocysteine levels both at baseline and at the end of the walking intervention decreased in the exercise group, but were still higher than in the healthy individuals. Average walking distance positively correlated with homocysteine decrease (p < 0.05). Total SF-36 score significantly improved (p < 0.02) mainly due to enhancements in the physical component score (p < 0.026). A 12-week unsupervised walking programme exhibits a pronounced HRR amelioration, possibly attenuates endothelial damage and induces a concomitant improvement in perceived quality of life in CHF patients.

  6. Dosimetric Comparison of High-Dose-Rate Brachytherapy and Intensity-Modulated Radiation Therapy as a Boost to the Prostate

    SciTech Connect

    Hermesse, Johanne; Biver, Sylvie; Jansen, Nicolas; Lenaerts, Eric; Nickers, Philippe

    2010-01-15

    Purpose: We compared the dose conformity of two radiation modalities: high-dose-rate brachytherapy (HDR BT) and intensity-modulated radiation therapy (IMRT) to deliver a boost to the prostate after external beam radiotherapy (EBRT). Methods and Materials: Ten successive patients with prostate adenocarcinoma treated with a single 10-Gy HDR BT boost after EBRT were investigated. Four theoretical IMRT plans were computed: (a) 32.85 Gy IMRT and (b) 26 Gy IMRT with CTV-PTV expansions, doses corresponding to the equivalent dose in 2-Gy fractions (EQD2) of one 10-Gy fraction calculated with a prostate alpha/beta ratio of respectively 1.5 and 3 Gy; and (c) 32.85 Gy IMRT and (d) 26 Gy IMRT without CTV-PTV expansions. The dose-volume histogram values converted in EQD2 with an alpha/beta ratio of 3 Gy for the organs at risk were compared. Results: The HDR BT plan delivered higher mean doses to the PTV compared with IMRT plans. In all, 33% of the rectal volume received a mean dose of 5.32 +- 0.65 Gy and 20% of bladder volume received 4.61 +- 1.24 Gy with HDR BT. In comparison, doses delivered with IMRT were respectively 13.4 +- 1.49 Gy and 10.81 +- 4 Gy, even if only 26 Gy was prescribed to the PTV with no CTV-PTV expansion (p < 0.0001). The hot spots inside the urethra were greater with HDR BT but acceptable. Conclusions: Use of HDR BT produced a more conformal plan for the boost to the prostate than IMRT even without CTV-PTV expansions.

  7. High Rate Digital Demodulator ASIC

    NASA Technical Reports Server (NTRS)

    Ghuman, Parminder; Sheikh, Salman; Koubek, Steve; Hoy, Scott; Gray, Andrew

    1998-01-01

    The architecture of High Rate (600 Mega-bits per second) Digital Demodulator (HRDD) ASIC capable of demodulating BPSK and QPSK modulated data is presented in this paper. The advantages of all-digital processing include increased flexibility and reliability with reduced reproduction costs. Conventional serial digital processing would require high processing rates necessitating a hardware implementation in other than CMOS technology such as Gallium Arsenide (GaAs) which has high cost and power requirements. It is more desirable to use CMOS technology with its lower power requirements and higher gate density. However, digital demodulation of high data rates in CMOS requires parallel algorithms to process the sampled data at a rate lower than the data rate. The parallel processing algorithms described here were developed jointly by NASA's Goddard Space Flight Center (GSFC) and the Jet Propulsion Laboratory (JPL). The resulting all-digital receiver has the capability to demodulate BPSK, QPSK, OQPSK, and DQPSK at data rates in excess of 300 Mega-bits per second (Mbps) per channel. This paper will provide an overview of the parallel architecture and features of the HRDR ASIC. In addition, this paper will provide an over-view of the implementation of the hardware architectures used to create flexibility over conventional high rate analog or hybrid receivers. This flexibility includes a wide range of data rates, modulation schemes, and operating environments. In conclusion it will be shown how this high rate digital demodulator can be used with an off-the-shelf A/D and a flexible analog front end, both of which are numerically computer controlled, to produce a very flexible, low cost high rate digital receiver.

  8. Target Heart Rate Calculator

    MedlinePlus

    ... workout Enter your age to find a target heart rate during exercise. You'll get the most out of your activities by staying within this range of heartbeats/minute. Please enter your age in years Calculate Your target heart rate is beats per minute. How to Check Your ...

  9. Reduced journal rates

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    The American Institute of Physics (AIP) offers reduced rates for subscriptions to its journals to individual members of affiliated societies, including AGU. The offer is limited to one subscription per person to each journal.Rates for 1985 for AGU members are listed below

  10. Metabolic rate measurement system

    NASA Technical Reports Server (NTRS)

    Koester, K.; Crosier, W.

    1980-01-01

    The Metabolic Rate Measurement System (MRMS) is an uncomplicated and accurate apparatus for measuring oxygen consumption and carbon dioxide production of a test subject. From this one can determine the subject's metabolic rate for a variety of conditions, such as resting or light exercise. MRMS utilizes an LSI/11-03 microcomputer to monitor and control the experimental apparatus.

  11. Beware Capital Charge Rates

    SciTech Connect

    Stauffer, Hoff

    2006-04-15

    The capital charge rate has a material effect in cost comparisons. Care should be taken to calculate it correctly and use it properly. The most common mistake is to use a nominal, rather than real, capital charge rate. To make matters worse, the common short-cut formula does not work well. (author)

  12. Scaling metabolic rate fluctuations

    PubMed Central

    Labra, Fabio A.; Marquet, Pablo A.; Bozinovic, Francisco

    2007-01-01

    Complex ecological and economic systems show fluctuations in macroscopic quantities such as exchange rates, size of companies or populations that follow non-Gaussian tent-shaped probability distributions of growth rates with power-law decay, which suggests that fluctuations in complex systems may be governed by universal mechanisms, independent of particular details and idiosyncrasies. We propose here that metabolic rate within individual organisms may be considered as an example of an emergent property of a complex system and test the hypothesis that the probability distribution of fluctuations in the metabolic rate of individuals has a “universal” form regardless of body size or taxonomic affiliation. We examined data from 71 individuals belonging to 25 vertebrate species (birds, mammals, and lizards). We report three main results. First, for all these individuals and species, the distribution of metabolic rate fluctuations follows a tent-shaped distribution with power-law decay. Second, the standard deviation of metabolic rate fluctuations decays as a power-law function of both average metabolic rate and body mass, with exponents −0.352 and −1/4 respectively. Finally, we find that the distributions of metabolic rate fluctuations for different organisms can all be rescaled to a single parent distribution, supporting the existence of general principles underlying the structure and functioning of individual organisms. PMID:17578913

  13. Extended rate equations

    SciTech Connect

    Shore, B.W.

    1981-01-30

    The equations of motion are discussed which describe time dependent population flows in an N-level system, reviewing the relationship between incoherent (rate) equations, coherent (Schrodinger) equations, and more general partially coherent (Bloch) equations. Approximations are discussed which replace the elaborate Bloch equations by simpler rate equations whose coefficients incorporate long-time consequences of coherence.

  14. Applications of Reaction Rate

    ERIC Educational Resources Information Center

    Cunningham, Kevin

    2007-01-01

    This article presents an assignment in which students are to research and report on a chemical reaction whose increased or decreased rate is of practical importance. Specifically, students are asked to represent the reaction they have chosen with an acceptable chemical equation, identify a factor that influences its rate and explain how and why it…

  15. Encoding of the amplitude modulation of pulsatile electrical stimulation in the feline cochlear nucleus by neurons in the inferior colliculus; effects of stimulus pulse rate

    NASA Astrophysics Data System (ADS)

    McCreery, Douglas; Han, Martin; Pikov, Victor; Yadav, Kamal; Pannu, Satinderpall

    2013-10-01

    Objectives. Persons without a functional auditory nerve cannot benefit from cochlear implants, but some hearing can be restored by an auditory brainstem implant (ABI) with stimulating electrodes implanted on the surface of the cochlear nucleus (CN). Most users benefit from their ABI, but speech recognition tends to be poorer than for users of cochlear implants. Psychophysical studies suggest that poor modulation detection may contribute to the limited performance of ABI users. In a cat model, we determined how the pulse rate of the electrical stimulus applied within or on the CN affects temporal and rate encoding of amplitude modulation (AM) by neurons in the central nucleus of the inferior colliculus (ICC). Approach. Stimulating microelectrodes were implanted chronically in and on the cats' CN, and multi-site recording microelectrodes were implanted chronically into the ICC. Encoding of AM pulse trains by neurons in the ICC was characterized as vector strength (VS), the synchrony of neural activity with the AM, and as the mean rate of neuronal action potentials (neuronal spike rate (NSR)). Main results. For intranuclear microstimulation, encoding of AM as VS was up to 3 dB greater when stimulus pulse rate was increased from 250 to 500 pps, but only for neuronal units with low best acoustic frequencies, and when the electrical stimulation was modulated at low frequencies (10-20 Hz). For stimulation on the surface of the CN, VS was similar at 250 and 500 pps, and the dynamic range of the VS was reduced for pulse rates greater than 250 pps. Modulation depth was encoded strongly as VS when the maximum stimulus amplitude was held constant across a range of modulation depth. This ‘constant maximum’ protocol allows enhancement of modulation depth while preserving overall dynamic range. However, modulation depth was not encoded as strongly as NSR. Significance. The findings have implications for improved sound processors for present and future ABIs. The performance of

  16. Reconfigurable intensity modulation and direct detection optical transceivers for variable-rate wavelength-division-multiplexing passive optical networks utilizing digital signal processing-based symbol mapper

    NASA Astrophysics Data System (ADS)

    Zhang, Zhiguo; Zhang, Bingbing; Chen, Yanxu; Chen, Xue

    2017-01-01

    Variable-rate intensity modulation and direct detection-based optical transceivers with software-controllable reconfigurability and transmission performance adaptability are experimentally demonstrated, utilizing M-QAM symbol mapping implemented in MATLAB® programs. A frequency division multiplexing-based symbol demapping and wavelength management method is proposed for the symbol demapper and tunable laser management used in colorless optical network unit.

  17. Hydroxychloroquine reduces heart rate by modulating the hyperpolarization-activated current If: Novel electrophysiological insights and therapeutic potential.

    PubMed

    Capel, Rebecca A; Herring, Neil; Kalla, Manish; Yavari, Arash; Mirams, Gary R; Douglas, Gillian; Bub, Gil; Channon, Keith; Paterson, David J; Terrar, Derek A; Burton, Rebecca-Ann B

    2015-10-01

    Bradycardic agents are of interest for the treatment of ischemic heart disease and heart failure, as heart rate is an important determinant of myocardial oxygen consumption. The purpose of this study was to investigate the propensity of hydroxychloroquine (HCQ) to cause bradycardia. We assessed the effects of HCQ on (1) cardiac beating rate in vitro (mice); (2) the "funny" current (If) in isolated guinea pig sinoatrial node (SAN) myocytes (1, 3, 10 µM); (3) heart rate and blood pressure in vivo by acute bolus injection (rat, dose range 1-30 mg/kg), (4) blood pressure and ventricular function during feeding (mouse, 100 mg/kg/d for 2 wk, tail cuff plethysmography, anesthetized echocardiography). In mouse atria, spontaneous beating rate was significantly (P < .05) reduced (by 9% ± 3% and 15% ± 2% at 3 and 10 µM HCQ, n = 7). In guinea pig isolated SAN cells, HCQ conferred a significant reduction in spontaneous action potential firing rate (17% ± 6%, 1 μM dose) and a dose-dependent reduction in If (13% ± 3% at 1 µM; 19% ± 2% at 3 µM). Effects were also observed on L-type calcium ion current (ICaL) (12% ± 4% reduction) and rapid delayed rectifier potassium current (IKr) (35% ± 4%) at 3 µM. Intravenous HCQ decreased heart rate in anesthetized rats (14.3% ± 1.1% at 15mg/kg; n = 6) without significantly reducing mean arterial blood pressure. In vivo feeding studies in mice showed no significant change in systolic blood pressure nor left ventricular function. We have shown that HCQ acts as a bradycardic agent in SAN cells, in atrial preparations, and in vivo. HCQ slows the rate of spontaneous action potential firing in the SAN through multichannel inhibition, including that of If. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  18. Hydroxychloroquine reduces heart rate by modulating the hyperpolarization-activated current If: Novel electrophysiological insights and therapeutic potential

    PubMed Central

    Capel, Rebecca A.; Herring, Neil; Kalla, Manish; Yavari, Arash; Mirams, Gary R.; Douglas, Gillian; Bub, Gil; Channon, Keith; Paterson, David J.; Terrar, Derek A.; Burton, Rebecca-Ann B.

    2015-01-01

    Background Bradycardic agents are of interest for the treatment of ischemic heart disease and heart failure, as heart rate is an important determinant of myocardial oxygen consumption. Objectives The purpose of this study was to investigate the propensity of hydroxychloroquine (HCQ) to cause bradycardia. Methods We assessed the effects of HCQ on (1) cardiac beating rate in vitro (mice); (2) the “funny” current (If) in isolated guinea pig sinoatrial node (SAN) myocytes (1, 3, 10 µM); (3) heart rate and blood pressure in vivo by acute bolus injection (rat, dose range 1–30 mg/kg), (4) blood pressure and ventricular function during feeding (mouse, 100 mg/kg/d for 2 wk, tail cuff plethysmography, anesthetized echocardiography). Results In mouse atria, spontaneous beating rate was significantly (P < .05) reduced (by 9% ± 3% and 15% ± 2% at 3 and 10 µM HCQ, n = 7). In guinea pig isolated SAN cells, HCQ conferred a significant reduction in spontaneous action potential firing rate (17% ± 6%, 1 μM dose) and a dose-dependent reduction in If (13% ± 3% at 1 µM; 19% ± 2% at 3 µM). Effects were also observed on L-type calcium ion current (ICaL) (12% ± 4% reduction) and rapid delayed rectifier potassium current (IKr) (35% ± 4%) at 3 µM. Intravenous HCQ decreased heart rate in anesthetized rats (14.3% ± 1.1% at 15mg/kg; n = 6) without significantly reducing mean arterial blood pressure. In vivo feeding studies in mice showed no significant change in systolic blood pressure nor left ventricular function. Conclusions We have shown that HCQ acts as a bradycardic agent in SAN cells, in atrial preparations, and in vivo. HCQ slows the rate of spontaneous action potential firing in the SAN through multichannel inhibition, including that of If. PMID:26025323

  19. The integral pulse frequency modulation model with time-varying threshold: application to heart rate variability analysis during exercise stress testing.

    PubMed

    Bailón, Raquel; Laouini, Ghailen; Grao, César; Orini, Michele; Laguna, Pablo; Meste, Olivier

    2011-03-01

    In this paper, an approach for heart rate variability analysis during exercise stress testing is proposed based on the integral pulse frequency modulation (IPFM) model, where a time-varying threshold is included to account for the nonstationary mean heart rate. The proposed technique allows the estimation of the autonomic nervous system (ANS) modulating signal using the methods derived for the IPFM model with constant threshold plus a correction, which is shown to be needed to take into account the time-varying mean heart rate. On simulations, this technique allows the estimation of the ANS modulation on the heart from the beat occurrence time series with lower errors than the IPFM model with constant threshold (1.1% ± 1.3% versus 15.0% ± 14.9%). On an exercise stress testing database, the ANS modulation estimated by the proposed technique is closer to physiology than that obtained from the IPFM model with constant threshold, which tends to overestimate the ANS modulation during the recovery and underestimate it during the initial rest.

  20. Intensity-modulated radiation therapy for pancreatic and prostate cancer using pulsed low–dose rate delivery techniques

    SciTech Connect

    Li, Jie; Lang, Jinyi; Wang, Pei; Kang, Shengwei; Lin, Mu-han; Chen, Xiaoming; Chen, Fu; Guo, Ming; Chen, Lili; Ma, Chang-Ming Charlie

    2014-01-01

    Reirradiation of patients who were previously treated with radiotherapy is vastly challenging. Pulsed low–dose rate (PLDR) external beam radiotherapy has the potential to reduce normal tissue toxicities while providing significant tumor control for recurrent cancers. This work investigates treatment planning techniques for intensity-modulated radiation therapy (IMRT)-based PLDR treatment of various sites, including cases with pancreatic and prostate cancer. A total of 20 patients with clinical recurrence were selected for this study, including 10 cases with pancreatic cancer and 10 with prostate cancer. Large variations in the target volume were included to test the ability of IMRT using the existing treatment planning system and optimization algorithm to deliver uniform doses in individual gantry angles/fields for PLDR treatments. Treatment plans were generated with 10 gantry angles using the step-and-shoot IMRT delivery technique, which can be delivered in 3-minute intervals to achieve an effective low dose rate of 6.7 cGy/min. Instead of dose constraints on critical structures, ring structures were mainly used in PLDR-IMRT optimization. In this study, the PLDR-IMRT plans were compared with the PLDR-3-dimensional conformal radiation therapy (3DCRT) plans and the PLDR-RapidArc plans. For the 10 cases with pancreatic cancer that were investigated, the mean planning target volume (PTV) dose for each gantry angle in the PLDR-IMRT plans ranged from 17.6 to 22.4 cGy. The maximum doses ranged between 22.9 and 34.8 cGy. The minimum doses ranged from 8.2 to 17.5 cGy. For the 10 cases with prostate cancer that were investigated, the mean PTV doses for individual gantry angles ranged from 18.8 to 22.6 cGy. The maximum doses per gantry angle were between 24.0 and 34.7 cGy. The minimum doses per gantry angle ranged from 4.4 to 17.4 cGy. A significant reduction in the organ at risk (OAR) dose was observed with the PLDR-IMRT plan when compared with that using the PLDR-3DCRT

  1. Body Sodium Overload Modulates the Firing Rate and Fos Immunoreactivity of Serotonergic Cells of Dorsal Raphe Nucleus

    PubMed Central

    Godino, Andrea; Pitra, Soledad; Carrer, Hugo F.; Vivas, Laura

    2013-01-01

    In order to determine whether serotonergic (5HT) dorsal raphe nucleus (DRN) cells are involved in body sodium status regulation, the effect of a s.c. infusion of either 2 M or 0.15 M NaCl on 5HT DRN neuron firing was studied using single unit extracellular recordings. In separate groups of 2 M and 0.15 M NaCl-infused rats, water intake, oxytocin (OT) plasma concentration, urine and plasma sodium and protein concentrations were also measured. Also, to determine the involvement of particular brain nuclei and neurochemical systems in body sodium overload (SO), animals from both groups were perfused for brain immunohistochemical detection of Fos, Fos-OT and Fos-5HT expression. SO produced a significant increase in serotonergic DRN neuron firing rate compared to baseline and 0.15 M NaCl-infused rats. As expected, 2 M NaCl s.c. infusion also induced a significant increase of water intake, diuresis and natriuresis, plasma sodium concentration and osmolality, even though plasma volume did not increase as indicated by changes in plasma protein concentration. The distribution of neurons along the forebrain and brainstem expressing Fos after SO showed the participation of the lamina terminalis, extended amygdala, supraoptic and paraventricular hypothalamic nuclei in the neural network that controls osmoregulatory responses. Both Fos-OT immunoreactive and plasma OT concentration increased after s.c. hypertonic sodium infusion. Finally, matching the “in vivo” electrophysiological study, SO doubled the number of Fos-5HT immunolabeled cells within the DRN. In summary, the results characterize the behavioral, renal and endocrine responses after body sodium overload without volume expansion and specify the cerebral nuclei that participate at different CNS levels in the control of these responses. The electrophysiological approach also allows us to determine in an “in vivo" model that DRN 5HT neurons increase their firing frequency during an increase in systemic sodium

  2. Body sodium overload modulates the firing rate and fos immunoreactivity of serotonergic cells of dorsal raphe nucleus.

    PubMed

    Godino, Andrea; Pitra, Soledad; Carrer, Hugo F; Vivas, Laura

    2013-01-01

    In order to determine whether serotonergic (5HT) dorsal raphe nucleus (DRN) cells are involved in body sodium status regulation, the effect of a s.c. infusion of either 2 M or 0.15 M NaCl on 5HT DRN neuron firing was studied using single unit extracellular recordings. In separate groups of 2 M and 0.15 M NaCl-infused rats, water intake, oxytocin (OT) plasma concentration, urine and plasma sodium and protein concentrations were also measured. Also, to determine the involvement of particular brain nuclei and neurochemical systems in body sodium overload (SO), animals from both groups were perfused for brain immunohistochemical detection of Fos, Fos-OT and Fos-5HT expression. SO produced a significant increase in serotonergic DRN neuron firing rate compared to baseline and 0.15 M NaCl-infused rats. As expected, 2 M NaCl s.c. infusion also induced a significant increase of water intake, diuresis and natriuresis, plasma sodium concentration and osmolality, even though plasma volume did not increase as indicated by changes in plasma protein concentration. The distribution of neurons along the forebrain and brainstem expressing Fos after SO showed the participation of the lamina terminalis, extended amygdala, supraoptic and paraventricular hypothalamic nuclei in the neural network that controls osmoregulatory responses. Both Fos-OT immunoreactive and plasma OT concentration increased after s.c. hypertonic sodium infusion. Finally, matching the "in vivo" electrophysiological study, SO doubled the number of Fos-5HT immunolabeled cells within the DRN. In summary, the results characterize the behavioral, renal and endocrine responses after body sodium overload without volume expansion and specify the cerebral nuclei that participate at different CNS levels in the control of these responses. The electrophysiological approach also allows us to determine in an "in vivo" model that DRN 5HT neurons increase their firing frequency during an increase in systemic sodium concentration

  3. The ratings game

    NASA Astrophysics Data System (ADS)

    Braben, Donald W.

    2009-04-01

    How sad to read a supposedly serious debate among distinguished physicists (February p19) about which combinations of the latest Research Assessment Exercise (RAE) ratings represent a university physics department's true strengths.

  4. Rating Your Cash Manager?

    ERIC Educational Resources Information Center

    Nielsen, George A.; Johannisson, Eric E.

    1989-01-01

    The primary objective of a public cash management policy should include safety, liquidity, yield, and legality. Contains a cash management policy/procedure checklist, a test for cash managers, and a formula for calculating the rate of return. (MLF)

  5. Historical Permit Fee Rates

    EPA Pesticide Factsheets

    This site will provide basic information on clean air permitting under the title V operating permits program, provide access to state and regional permitting programs, and maintain access to proposed and final regulatory requirements. Historical fee rates.

  6. Handbook of noise ratings

    NASA Technical Reports Server (NTRS)

    Pearsons, K. S.; Bennett, R. L.

    1975-01-01

    Handbook announced in Tech Brief is compendium of information describing multifarious noise methods now in use. Reference material gives user better access to definitions, application, and calculation procedures of current noise rating methods.

  7. Video Slope Rate Detector.

    DTIC Science & Technology

    The patent describes an apparatus for measuring the rate of change of voltage and the polarity of a pulse having a two input terminal differential amplifier with a delay line connected to one of the input terminals.

  8. Rating the Risks.

    ERIC Educational Resources Information Center

    Slovic, Paul; And Others

    1979-01-01

    Explains how people arrive at personal hazard assessments. Explores why people overestimate some hazards and underestimate others. Examines risk ratings for activities and technologies such as nuclear power, motor vehicles, pesticides, and vaccinations. (MA)

  9. Rating Your Cash Manager?

    ERIC Educational Resources Information Center

    Nielsen, George A.; Johannisson, Eric E.

    1989-01-01

    The primary objective of a public cash management policy should include safety, liquidity, yield, and legality. Contains a cash management policy/procedure checklist, a test for cash managers, and a formula for calculating the rate of return. (MLF)

  10. Burning Rate Emulator

    NASA Image and Video Library

    The Burning Rate Emulator is a gas fuel investigation attempting to emulate the burning of solids to improve our understanding of materials''flammability over a wide range of conditions. The approa...

  11. Rating the Risks.

    ERIC Educational Resources Information Center

    Slovic, Paul; And Others

    1979-01-01

    Explains how people arrive at personal hazard assessments. Explores why people overestimate some hazards and underestimate others. Examines risk ratings for activities and technologies such as nuclear power, motor vehicles, pesticides, and vaccinations. (MA)

  12. High population increase rates.

    PubMed

    1991-09-01

    In addition to its economic and ethnic difficulties, the USSR faces several pressing demographic problems, including high population increase rates in several of its constituent republics. It has now become clear that although the country's rigid centralized planning succeeded in covering the basic needs of people, it did not lead to welfare growth. Since the 1970s, the Soviet economy has remained sluggish, which as led to increase in the death and birth rates. Furthermore, the ideology that held that demography could be entirely controlled by the country's political and economic system is contradicted by current Soviet reality, which shows that religion and ethnicity also play a significant role in demographic dynamics. Currently, Soviet republics fall under 2 categories--areas with high or low natural population increase rates. Republics with low rates consist of Christian populations (Armenia, Moldavia, Georgia, Byelorussia, Russia, Lithuania, Estonia, Latvia, Ukraine), while republics with high rates are Muslim (Tadzhikistan, Uzbekistan, Turkmenistan, Kirgizia, Azerbaijan Kazakhstan). The later group has natural increase rates as high as 3.3%. Although the USSR as a whole is not considered a developing country, the later group of republics fit the description of the UNFPA's priority list. Another serious demographic issue facing the USSR is its extremely high rate of abortion. This is especially true in the republics of low birth rates, where up to 60% of all pregnancies are terminated by induced abortions. Up to 1/5 of the USSR's annual health care budget is spent on clinical abortions -- money which could be better spent on the production of contraceptives. Along with the recent political and economic changes, the USSR is now eager to deal with its demographic problems.

  13. Heart Rate Monitor

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In the mid 70's, NASA saw a need for a long term electrocardiographic electrode suitable for use on astronauts. Heart Rate Inc.'s insulated capacitive electrode is constructed of thin dielectric film applied to stainless steel surface, originally developed under a grant by Texas Technical University. HRI, Inc. was awarded NASA license and continued development of heart rate monitor for use on exercise machines for physical fitness and medical markets.

  14. Rates of Gravel Dispersion

    NASA Astrophysics Data System (ADS)

    Haschenburger, J. K.

    2010-12-01

    Sediment transfers in gravel-bed rivers involve the three-dimensional dispersion of mixed size sediment. From a kinematics standpoint, few studies are available to inform on the streamwise and vertical rates of sediment dispersion in natural channels. This research uses a gravel tracing program to quantify dispersion rates over 19 flood seasons. Empirical observations come from Carnation Creek, a small gravel-bed river with large woody debris located on the west coast of Vancouver Island, Canada. Frequent floods and the relatively limited armor layer facilitate streambed activity and relatively high bedload transport rates, typically under partial sediment transport conditions. Over 2500 magnetically tagged stones, ranging in size from 16 to 180 mm, were deployed on the bed surface between 1989 and 1992 in four generations. To quantify gravel dispersion over distances up to 2.6 km, observations are taken from 11 recoveries. Over 280 floods capable of moving bedload occurred during this period, with five exceeding the estimated bankfull discharge. Streamwise dispersion is quantified by virtual velocity, while dispersion into the streambed is quantified by a vertical burial rate. The temporal trend in streamwise dispersion rates is described by a power function. Initial virtual velocities decline rapidly from around 1.4 m/hr to approach an asymptote value of about 0.2 m/hr. The rapid change corresponds to a significant increase in the proportion of buried tracers due to vertical mixing. Initial burial rates reflect the magnitude of the first flood after tracer deployment and range from 0.07 to 0.46 cm/hr depending on tracer generation. Burial rates converge to about 0.06 cm/hr after the fourth flood season and then gradually decline to about 0.01 cm/hr. Thus, the rate of streamwise dispersion exceeds that of vertical dispersion by three orders of magnitude when the movement of sediment routinely activated by floods is considered.

  15. Noninvasive Heart Rate Monitor

    DTIC Science & Technology

    1983-07-31

    plethysmography can be applied to various parts of the body such as finger, toe, ear, forehead, neck, wrist and so on. The choice of location is predicated upon...frequency, hydrostatic, cardiac vibration wave is also explored. 3 2.0 METHODOLOGY The basic methodology and underlying principle of the heart rate monitor...regarding heart rate can be extracted in a number of ways. In the present application, the Doppler effect will be utilized. The principle of

  16. Heart Rate Monitors

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Under a NASA grant, Dr. Robert M. Davis and Dr. William M. Portnoy came up with a new type of electrocardiographic electrode that would enable long term use on astronauts. Their invention was an insulated capacitive electrode constructed of a thin dielectric film. NASA subsequently licensed the electrode technology to Richard Charnitski, inventor of the VersaClimber, who founded Heart Rate, Inc., to further develop and manufacture personal heart monitors and to produce exercise machines using the technology for the physical fitness, medical and home markets. Same technology is on both the Home and Institutional Model VersaClimbers. On the Home Model an infrared heart beat transmitter is worn under exercise clothing. Transmitted heart rate is used to control the work intensity on the VersaClimber using the heart rate as the speedometer of the exercise. This offers advantages to a full range of users from the cardiac rehab patient to the high level physical conditioning of elite athletes. The company manufactures and markets five models of the 1*2*3 HEART RATE monitors that are used wherever people exercise to accurately monitor their heart rate. Company is developing a talking heart rate monitor that works with portable headset radios. A version of the heart beat transmitter will be available to the manufacturers of other aerobic exercise machines.

  17. Hydration rate of obsidian.

    PubMed

    Friedman, I; Long, W

    1976-01-30

    The hydration rates of 12 obsidian samples of different chemical compositions were measured at temperatures from 95 degrees to 245 degrees C. An expression relating hydration rate to temperature was derived for each sample. The SiO(2) content and refractive index are related to the hydration rate, as are the CaO, MgO, and original water contents. With this information it is possible to calculate the hydration rate of a sample from its silica content, refractive index, or chemical index and a knowledge of the effective temperature at which the hydration occurred. The effective hydration temperature can be either measured or approximated from weather records. Rates have been calculated by both methods, and the results show that weather records can give a good approximation to the true EHT, particularly in tropical and subtropical climates. If one determines the EHT by any of the methods suggested, and also measures or knows the rate of hydration of the particular obsidian used, it should be possible to carry out absolute dating to +/- 10 percent of the true age over periods as short as several years and as long as millions of years.

  18. SU-E-P-15: Technique Factor Modulation and Reference Plane Air Kerma Rates in Response to Simulated Patient Thickness Variations for a Sample of Current Generation Fluoroscopes

    SciTech Connect

    Wunderle, K; Rakowski, J; Dong, F

    2015-06-15

    Purpose: To evaluate and compare approaches to technique factor modulation and air kerma rates in response to simulated patient thickness variations for four state-of-the-art and one previous-generation interventional fluoroscopes. Methods: A polymethyl methacrylate (PMMA) phantom was used as a tissue surrogate for the purposes of determining fluoroscopic reference plane air kerma rates, kVp, mA, and spectral filtration over a wide range of simulated tissue thicknesses. Data were acquired for each fluoroscopic and acquisition dose curve within a default abdomen or body imaging protocol. Results: The data obtained indicated vendor- and model-specific variations in the approach to technique factor modulation and reference plane air kerma rates across a range of tissue thicknesses. Some vendors have made hardware advances increasing the radiation output capabilities of their fluoroscopes; this was evident in the acquisition air kerma rates. However, in the imaging protocol evaluated, all of the state-of-the-art systems had relatively low air kerma rates in the fluoroscopic low-dose imaging mode as compared to the previous-generation unit. Each of the newest-generation systems also employ copper filtration in the selected protocol in the acquisition mode of imaging; this is a substantial benefit, reducing the skin entrance dose to the patient in the highest dose-rate mode of fluoroscope operation. Conclusion: Understanding how fluoroscopic technique factors are modulated provides insight into the vendor-specific image acquisition approach and provides opportunities to optimize the imaging protocols for clinical practice. The enhanced radiation output capabilities of some of the fluoroscopes may, under specific conditions, may be beneficial; however, these higher output capabilities also have the potential to lead to unnecessarily high dose rates. Therefore, all parties involved in imaging, including the clinical team, medical physicists, and imaging vendors, must work

  19. Modelling Heart Rate Kinetics

    PubMed Central

    Zakynthinaki, Maria S.

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual’s cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women). PMID:25876164

  20. Modelling heart rate kinetics.

    PubMed

    Zakynthinaki, Maria S

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual's cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women).

  1. Quantify Degradation Rates and Mechanisms of PV Modules and Systems Installed in Florida Through Comprehensive Experimental and Theoretical Analysis (Poster)

    SciTech Connect

    Sorloaica-Hickman, N.; Davis, K.; Kurtz, S.; Jordan, D.

    2011-02-01

    The economic viability of photovoltaic (PV) technologies is inextricably tied to both the electrical performance and degradation rate of the PV systems, which are the generators of electrical power in PV systems. Over the past 15 years, performance data have been collected on numerous PV systems installed throughout the state of Florida and will be presented.

  2. Cooling Rates of Chondrules

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Hewins, R. H.; Eiben, B. A.

    1995-09-01

    Cooling rates for chondrules are among many aspects of chondrule forming events currently under debate and estimates by different authors vary considerably. Calculations based on radiation from isolated chondrules yield an extremely high cooling rate of ~10^5 degrees C/hr [1]. The cooling rates derived from previous petrological and experimental studies are much lower but inconsistent, ranging from 5 - 100 degrees C/hr [2] to ~1000 degrees C/hr [3]. Since cooling rates bear important information about the chondrule-forming environment, they need to be more tightly constrained. Here we re-evaluate the chondrule cooling rates based on the results of our recent flash heating experiments, mainly the volatile loss data, as well as textures, and olivine zoning profiles of the chondrule analog materials. Linear cooling vs. cooling curves. Many previous studies either assumed or used linear cooling rates for chondrules [2,3]. In reality, even with simple radiative cooling, the cooling rates should have followed a non-linear path, according to the Stefan- Boltzmann law. We used non-linear cooling rates throughout our experiments, and our observations show that the initial cooling rate at the high temperature end of a specific cooling curve affects chondrule properties most. Volatile loss results. Our Na and S loss experiments [4] have shown that to reproduce the very high Na contents [5,6] and primary sulfide [7] found in some natural chondrules, heating has to be brief, but fast cooling and relatively high fO2 are also essential. With an fO2 of ~10^(-10) atm, for a type II chondrule flash heated to its liquidus temperature, cooling curves beginning at ~2500 degrees C/hr are necessary to retain >90% of its original Na content or part of its S, unless the ambient gas is very enriched in these elements [8]. Under lower fO2, or for type I chondrule composition, even higher cooling rates are required. Textures and olivine zoning with ~10^1 - ~10^3 degrees C/hr initial cooling

  3. Habituation to low or high protein intake does not modulate basal or postprandial muscle protein synthesis rates: a randomized trial.

    PubMed

    Gorissen, Stefan Hm; Horstman, Astrid Mh; Franssen, Rinske; Kouw, Imre Wk; Wall, Benjamin T; Burd, Nicholas A; de Groot, Lisette Cpgm; van Loon, Luc Jc

    2017-02-01

    Muscle mass maintenance is largely regulated by basal muscle protein synthesis rates and the ability to increase muscle protein synthesis after protein ingestion. To our knowledge, no previous studies have evaluated the impact of habituation to either low protein intake (LOW PRO) or high protein intake (HIGH PRO) on the postprandial muscle protein synthetic response. We assessed the impact of LOW PRO compared with HIGH PRO on basal and postprandial muscle protein synthesis rates after the ingestion of 25 g whey protein. Twenty-four healthy, older men [age: 62 ± 1 y; body mass index (in kg/m(2)): 25.9 ± 0.4 (mean ± SEM)] participated in a parallel-group randomized trial in which they adapted to either a LOW PRO diet (0.7 g · kg(-1) · d(-1); n = 12) or a HIGH PRO diet (1.5 g · kg(-1) · d(-1); n = 12) for 14 d. On day 15, participants received primed continuous l-[ring-(2)H5]-phenylalanine and l-[1-(13)C]-leucine infusions and ingested 25 g intrinsically l-[1-(13)C]-phenylalanine- and l-[1-(13)C]-leucine-labeled whey protein. Muscle biopsies and blood samples were collected to assess muscle protein synthesis rates as well as dietary protein digestion and absorption kinetics. Plasma leucine concentrations and exogenous phenylalanine appearance rates increased after protein ingestion (P < 0.01) with no differences between treatments (P > 0.05). Plasma exogenous phenylalanine availability over the 5-h postprandial period was greater after LOW PRO than after HIGH PRO (61% ± 1% compared with 56% ± 2%, respectively; P < 0.05). Muscle protein synthesis rates increased from 0.031% ± 0.004% compared with 0.039% ± 0.007%/h in the fasted state to 0.062% ± 0.005% compared with 0.057% ± 0.005%/h in the postprandial state after LOW PRO compared with HIGH PRO, respectively (P < 0.01), with no differences between treatments (P = 0.25). Habituation to LOW PRO (0.7 g · kg(-1) · d(-1)) compared with HIGH PRO (1.5 g · kg(-1) · d(-1)) augments the postprandial

  4. Cardiac vagal modulation of heart rate during prolonged submaximal exercise in animals with healed myocardial infarctions: effects of training.

    PubMed

    Kukielka, Monica; Seals, Douglas R; Billman, George E

    2006-04-01

    The present study investigated the effects of long-duration exercise on heart rate variability [as a marker of cardiac vagal tone (VT)]. Heart rate variability (time series analysis) was measured in mongrel dogs (n = 24) with healed myocardial infarctions during 1 h of submaximal exercise (treadmill running at 6.4 km/h at 10% grade). Long-duration exercise provoked a significant (ANOVA, all P < 0.01, means +/- SD) increase in heart rate (1st min, 165.3 +/- 15.6 vs. last min, 197.5 +/- 21.5 beats/min) and significant reductions in high frequency (0.24 to 1.04 Hz) power (VT: 1st min, 3.7 +/- 1.5 vs. last min, 1.0 +/- 0.9 ln ms(2)), R-R interval range (1st min, 107.9 +/- 38.3 vs. last min, 28.8 +/- 13.2 ms), and R-R interval SD (1st min, 24.3 +/- 7.7 vs. last min 6.3 +/- 1.7 ms). Because endurance exercise training can increase cardiac vagal regulation, the studies were repeated after either a 10-wk exercise training (n = 9) or a 10-wk sedentary period (n = 7). After training was completed, long-duration exercise elicited smaller increases in heart rate (pretraining: 1st min, 156.0 +/- 13.8 vs. last min, 189.6 +/- 21.9 beats/min; and posttraining: 1st min, 149.8 +/- 14.6 vs. last min, 172.7 +/- 8.8 beats/min) and smaller reductions in heart rate variability (e.g., VT, pretraining: 1st min, 4.2 +/- 1.7 vs. last min, 0.9 +/- 1.1 ln ms(2); and posttraining: 1st min, 4.8 +/- 1.1 vs. last min, 2.0 +/- 0.6 ln ms(2)). The response to long-duration exercise did not change in the sedentary animals. Thus the heart rate increase that accompanies long-duration exercise results, at least in part, from reductions in cardiac vagal regulation. Furthermore, exercise training attenuated these exercise-induced reductions in heart rate variability, suggesting maintenance of a higher cardiac vagal activity during exercise in the trained state.

  5. Heart rate turbulence.

    PubMed

    Cygankiewicz, Iwona

    2013-01-01

    Heart rate turbulence (HRT) is a baroreflex-mediated biphasic reaction of heart rate in response to premature ventricular beats. Heart rate turbulence is quantified by: turbulence onset (TO) reflecting the initial acceleration of heart rate following premature beat and turbulence slope (TS) describing subsequent deceleration of heart rate. Abnormal HRT identifies patients with autonomic dysfunction or impaired baroreflex sensitivity due to variety of disorders, but also may reflect changes in autonomic nervous system induced by different therapeutic modalities such as drugs, revascularization, or cardiac resynchronization therapy. More importantly, impaired HRT has been shown to identify patients at high risk of all-cause mortality and sudden death, particularly in postinfarction and congestive heart failure patients. It should be emphasized that abnormal HRT has a well-established role in stratification of postinfarction and heart failure patients with relatively preserved left ventricular ejection fraction. The ongoing clinical trials will document whether HRT can be used to guide implantation of cardioverter-defibrillators in this subset of patients, not covered yet by ICD guidelines. This review focuses on the current state-of-the-art knowledge regarding clinical significance of HRT in detection of autonomic dysfunction and regarding the prognostic significance of this parameter in predicting all-cause mortality and sudden death.

  6. Inertial wave beams and inertial wave modes in a rotating cylinder with time-modulated rotation rate

    NASA Astrophysics Data System (ADS)

    Borcia, Ion D.; Ghasemi V., Abouzar; Harlander, Uwe

    2014-05-01

    Inertial gravity waves play an crucial role in atmospheres, oceans, and the fluid inside of planets and moons. In the atmosphere, the effect of rotation is neglected for small wavelength and the waves bear the character of internal gravity waves. For long waves, the hydrostatic assumption is made which in turn makes the atmosphere inelastic with respect to inertial motion. In contrast, in the Earth's interior, pure inertial waves are considered as an important fundamental part of the motion. Moreover, as the deep ocean is nearly homogeneous, there the inertial gravity waves bear the character of inertial waves. Excited at the oceans surface mainly due to weather systems the waves can propagate downward and influence the deep oceans motion. In the light of the aforesaid it is important to understand better fundamental inertial wave dynamics. We investigate inertial wave modes by experimental and numerical methods. Inertial modes are excited in a fluid filled rotating annulus by modulating the rotation rate of the outer cylinder and the upper and lower lids. This forcing leads to inertial wave beams emitted from the corner regions of the annulus due to periodic motions in the boundary layers (Klein et al., 2013). When the forcing frequency matches with the eigenfrequency of the rotating annulus the beam pattern amplitude is increasing, the beams broaden and mode structures can be observed (Borcia et al., 2013a). The eigenmodes are compared with analytical solutions of the corresponding inviscid problem (Borcia et al, 2013b). In particular for the pressure field a good agreement can be found. However, shear layers related to the excited wave beams are present for all frequencies. This becomes obvious in particular in the experimental visualizations that are done by using Kalliroscope particles, highlighting relative motion in the fluid. Comparing the eigenfrequencies we find that relative to the analytical frequencies, the experimental and numerical ones show a small

  7. 77 FR 59447 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-27

    ... Doc No: 2012-23732] SMALL BUSINESS ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional ``peg'' rate (13 CFR 120.214) on a quarterly basis. This rate... direct loan. This rate may be used as a base rate for guaranteed fluctuating interest rate SBA loans...

  8. 78 FR 39434 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-01

    ... Doc No: 2013-15648] SMALL BUSINESS ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional ``peg'' rate (13 CFR 120.214) on a quarterly basis. This rate... direct loan. This rate may be used as a base rate for guaranteed fluctuating interest rate SBA loans...

  9. 77 FR 76586 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-28

    ... Doc No: 2012-31295] SMALL BUSINESS ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional ``peg'' rate (13 CFR 120.214) on a quarterly basis. This rate... direct loan. This rate may be used as a base rate for guaranteed fluctuating interest rate SBA loans...

  10. Noninvasive Heart Rate Monitor

    DTIC Science & Technology

    1983-08-01

    NUMOEN2. GVT ACCESSION NO.2 ReCIPICUTS CATALOG NUMOeaR 14 -A674P ;-FR 4. TITLE (end S.dU. L TYPE OF RgPORT & PCFmOO covgeno Noninvasive Heart Rate monitor...WHNWIM AMINOw3 I& SUPPLEMENTARYV NOTES A9-W A IS. KCY WORDS (Canam. an ,. d" it4 II wooe.p ad IiEEr 6F AAm Heart Raet Monitor; Doppler Detector...of using a handheld, battery operated, cv microwave radar, operating at 2.45 GHs, for use as a heart rate monitor under chemically contaminated

  11. Weather Balloon Ascent Rate

    NASA Astrophysics Data System (ADS)

    Denny, Mark

    2016-05-01

    The physics of a weather balloon is analyzed. The surprising aspect of the motion of these balloons is that they ascend to great altitudes (typically 35 km) at a more or less constant rate. Such behavior is not surprising near the ground—say for a helium-filled party balloon rising from street level to the top of the Empire State building—but it is unexpected for a balloon that rises to altitudes where the air is rarefied. We show from elementary physical laws why the ascent rate is approximately constant.

  12. Rate of Dehydration and Cumulative Desiccation Stress Interacted to Modulate Desiccation Tolerance of Recalcitrant Cocoa and Ginkgo Embryonic Tissues1

    PubMed Central

    Liang, Yongheng; Sun, Wendell Q.

    2002-01-01

    Rate of dehydration greatly affects desiccation tolerance of recalcitrant seeds. This effect is presumably related to two different stress vectors: direct mechanical or physical stress because of the loss of water and physicochemical damage of tissues as a result of metabolic alterations during drying. The present study proposed a new theoretic approach to represent these two types of stresses and investigated how seed tissues responded differently to two stress vectors, using the models of isolated cocoa (Theobroma cacao) and ginkgo (Ginkgo biloba) embryonic tissues dehydrated under various drying conditions. This approach used the differential change in axis water potential (ΔΨ/Δt) to quantify rate of dehydration and the intensity of direct physical stress experienced by embryonic tissues during desiccation. Physicochemical effect of drying was expressed by cumulative desiccation stress [∫\\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\pagestyle{empty} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}{\\mathrm{_{o}^{t}}}\\end{equation*}\\end{document}f(ψ,t)], a function of both the rate and time of dehydration. Rapid dehydration increased the sensitivity of embryonic tissues to desiccation as indicated by high critical water contents, below which desiccation damage occurred. Cumulative desiccation stress increased sharply under slow drying conditions, which was also detrimental to embryonic tissues. This quantitative analysis of the stress-time-response relationship helps to understand the physiological basis for the existence of an optimal dehydration rate, with which maximum desiccation tolerance could be achieved. The established numerical analysis model will prove valuable for the design of experiments that aim to elucidate biochemical and physiological mechanisms of desiccation tolerance. PMID:11950981

  13. The elastic transfer model of angular rate modulation in F1-ATPase stalling and controlled rotation experiments

    NASA Astrophysics Data System (ADS)

    Volkán-Kacsó, S.

    2017-06-01

    The recent experimental, theoretical and computational advances in the field of F1-ATPase single-molecule microscopy are briefly surveyed. The role of theory is revealed in the statistical analysis, interpretation and prediction of single-molecule experimental trajectories, and in linking them with atomistic simulations. In particular, a theoretical model of elastically coupled molecular group transfer is reviewed and a detailed method for its application in stalling and controlled rotation experiments is provided. It is shown how the model can predict, using previous experiments, the rates of ligand binding/release processes (steps) and their exponential dependence on rotor angle in these experiments. The concept of Brønsted slopes is reviewed in the context of the single-molecule experiments, and the rate versus rotor angle relations are explained using the elastic model. These experimental data are treated in terms of the effect of thermodynamic driving forces on the rates assuming that the rotor shaft is elastically coupled to stator ring subunits in which the steps occur. In the application of the group transfer model on an extended angular range processes leading up to the transfer are discussed. Implications for large-scale atomistic simulation are suggested for the treatment of torque-generating steps.

  14. Respiratory rate can be modulated by long-loop muscular reflexes, a possible factor in involuntary cessation of apnea.

    PubMed

    Balestra, Costantino; Levenez, Morgan; Lafère, Pierre; Dachy, Bernard; Ezquer, Mikel; Germonpré, Peter

    2011-03-01

    The main limiting factors determining apnea time are generally considered to be related to blood and cerebrospinal fluid chemistry. Several physiological (adaptive) mechanisms and some psychologic parameters, such as motivation, are also known to increase apnea time. We wished to study the link between peripheral muscle fatigue, the concomitant alteration of long latency (transcortical) reflexes and respiratory control. Fatigue was induced in a small hand muscle (abductor pollicis brevis) (n = 11). This muscle is sufficiently small that its fatigue and the resulting production of metabolites are unlikely to alter whole-blood biochemistry. The Hoffmann reflex, an involuntary reaction to electrical stimulation of muscle afferent sensory fibreswas studied, as was the long latency reflex (LLR) using the Dueschl method in which electrical stimulation is superimposed on a slight voluntary contraction, Different fatiguing protocols were performed, and respiratory rate continuously recorded. The 'muscular metabolites increasing protocol' (at 50% maximum voluntary contraction, MVC) showed a significant dissociation between the decreases in the H-reflex and the LLR, compared to contraction at 25% MVC. This was associated with an increase in the respiratory rate to 148.25 (SD 11.37)% of control at 3 min (the maximum time the contraction could be sustained), whereas at 25% MVC, respiratory rate did not change during the contraction. This suggests a peripherally mediated, central input to the respiratory centres, triggering a powerful stimulus when metabolites accumulate in muscles. We believe this to be a possible mechanism terminating extreme breath holds.

  15. Growth rate and cell size modulate the synthesis of, and requirement for, G1-phase cyclins at start.

    PubMed

    Schneider, Brandt L; Zhang, Jian; Markwardt, J; Tokiwa, George; Volpe, Tom; Honey, Sangeet; Futcher, Bruce

    2004-12-01

    In Saccharomyces cerevisiae, commitment to cell cycle progression occurs at Start. Progression past Start requires cell growth and protein synthesis, a minimum cell size, and G(1)-phase cyclins. We examined the relationships among these factors. Rapidly growing cells expressed, and required, dramatically more Cln protein than did slowly growing cells. To clarify the role of cell size, we expressed defined amounts of CLN mRNA in cells of different sizes. When Cln was expressed at nearly physiological levels, a critical threshold of Cln expression was required for cell cycle progression, and this critical threshold varied with both cell size and growth rate: as cells grew larger, they needed less CLN mRNA, but as cells grew faster, they needed more Cln protein. At least in part, large cells had a reduced requirement for CLN mRNA because large cells generated more Cln protein per unit of mRNA than did small cells. When Cln was overexpressed, it was capable of promoting Start rapidly, regardless of cell size or growth rate. In summary, the amount of Cln required for Start depends dramatically on both cell size and growth rate. Large cells generate more Cln1 or Cln2 protein for a given amount of CLN mRNA, suggesting the existence of a novel posttranscriptional size control mechanism.

  16. Power Spectrum Analysis of Physikalisch-Technische Bundesanstalt Decay-Rate Data: Evidence for Solar Rotational Modulation

    NASA Astrophysics Data System (ADS)

    Sturrock, P. A.; Buncher, J. B.; Fischbach, E.; Gruenwald, J. T.; Javorsek, D.; Jenkins, J. H.; Lee, R. H.; Mattes, J. J.; Newport, J. R.

    2010-12-01

    Evidence for an anomalous annual periodicity in certain nuclear-decay data has led to speculation on a possible solar influence on nuclear processes. We have recently analyzed data concerning the decay rates of 36Cl and 32Si, acquired at the Brookhaven National Laboratory (BNL), to search for evidence that might be indicative of a process involving solar rotation. Smoothing of the power spectrum by weighted-running-mean analysis leads to a significant peak at frequency 11.18 year-1, which is lower than the equatorial synodic rotation rates of the convection and radiative zones. This article concerns measurements of the decay rates of 226Ra acquired at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. We find that a similar (but not identical) analysis yields a significant peak in the PTB dataset at frequency 11.21 year-1, and a peak in the BNL dataset at 11.25 year-1. The change in the BNL result is not significant, since the uncertainties in the BNL and PTB analyses are estimated to be 0.13 year-1 and 0.07 year-1, respectively. Combining the two running means by forming the joint power statistic leads to a highly significant peak at frequency 11.23 year-1. We will briefly comment on the possible implications of these results for solar physics and for particle physics.

  17. Paradoxes in Film Ratings

    ERIC Educational Resources Information Center

    Moore, Thomas L.

    2006-01-01

    The author selected a simple random sample of 100 movies from the "Movie and Video Guide" (1996), by Leonard Maltin. The author's intent was to obtain some basic information on the population of roughly 19,000 movies through a small sample. The "Movie and Video Guide" by Leonard Maltin is an annual ratings guide to movies. While not all films ever…

  18. Paradoxes in Film Ratings

    ERIC Educational Resources Information Center

    Moore, Thomas L.

    2006-01-01

    The author selected a simple random sample of 100 movies from the "Movie and Video Guide" (1996), by Leonard Maltin. The author's intent was to obtain some basic information on the population of roughly 19,000 movies through a small sample. The "Movie and Video Guide" by Leonard Maltin is an annual ratings guide to movies. While not all films ever…

  19. Toy Stories: Modeling Rates

    ERIC Educational Resources Information Center

    Swanson, Patricia E.

    2015-01-01

    Elementary school mathematics is increasingly recognized for its crucial role in developing the foundational skills and understandings for algebra. In this article, the author uses a lesson to introduce the concept of "rates"--comparing two different types and units of measure--and how to graph them. Described is the lesson and shared…

  20. Variable Rate Irrigation

    USDA-ARS?s Scientific Manuscript database

    Systems are available to producers with the ability to make variable-rate applications of defoliants, fertilizer, lime, pesticides, plant growth regulators, and seed. These systems could potentially offer a producer great cost savings; however, the full potential of these benefits and savings cannot...

  1. Variable rate irrigation

    USDA-ARS?s Scientific Manuscript database

    Systems are available to producers to make variable-rate applications of defoliants, fertilizer, lime, pesticides, plant growth regulators, and seed. These systems could potentially offer cost savings to a producer; however, the full potential of the benefits and savings cannot be realized if water ...

  2. Variable rate irrigation (VRI)

    USDA-ARS?s Scientific Manuscript database

    Variable rate irrigation (VRI) technology is now offered by all major manufacturers of moving irrigation systems, mostly on center pivot irrigation systems. Variable irrigation depths may be controlled by sector only, in which case only the speed of the irrigation lateral is regulated. Or, variable ...

  3. Snowmelt rate dictates streamflow

    NASA Astrophysics Data System (ADS)

    Barnhart, Theodore B.; Molotch, Noah P.; Livneh, Ben; Harpold, Adrian A.; Knowles, John F.; Schneider, Dominik

    2016-08-01

    Declining mountain snowpack and earlier snowmelt across the western United States has implications for downstream communities. We present a possible mechanism linking snowmelt rate and streamflow generation using a gridded implementation of the Budyko framework. We computed an ensemble of Budyko streamflow anomalies (BSAs) using Variable Infiltration Capacity model-simulated evapotranspiration, potential evapotranspiration, and estimated precipitation at 1/16° resolution from 1950 to 2013. BSA was correlated with simulated baseflow efficiency (r2 = 0.64) and simulated snowmelt rate (r2 = 0.42). The strong correlation between snowmelt rate and baseflow efficiency (r2 = 0.73) links these relationships and supports a possible streamflow generation mechanism wherein greater snowmelt rates increase subsurface flow. Rapid snowmelt may thus bring the soil to field capacity, facilitating below-root zone percolation, streamflow, and a positive BSA. Previous works have shown that future increases in regional air temperature may lead to earlier, slower snowmelt and hence decreased streamflow production via the mechanism proposed by this work.

  4. Rating helicopter noise

    NASA Technical Reports Server (NTRS)

    Leverton, J. W.; Southwood, B. J.; Pike, A. C.

    1978-01-01

    The effectiveness of the EPNL procedure in quantifying helicopter blade slap and tail rotor noise heard on approach some distance from the flyover position is addressed. Alternative methods of rating helicopter noise are reviewed including correction procedures to the EPNL concept which account for blade slap and tail rotor noise. The impact of the use of such corrections is examined.

  5. Currency Exchange Rates.

    ERIC Educational Resources Information Center

    Siler, Carl R.

    This curriculum unit of the Muncie (Indiana) Southside High School is to simulate the dynamics of foreign currency exchange rates from the perspectives of: (1) a major U.S. corporation, ABB Power T & D Company, Inc., of Muncie, Indiana, a manufacturer of large power transformers for the domestic and foreign markets; and (2) individual…

  6. Poetry Methods Rating Scale.

    ERIC Educational Resources Information Center

    Gallo, Donald R.

    Designed to assess high school teachers' attitudes about teaching poetry, this questionnaire asked teachers to respond to a 38-item poetry methods rating scale (PMRS) on a seven-point scale (from "strongly agree" to "strongly disagree"). The items for the questionnaire were derived from a study of popular methods texts for…

  7. What's in a Rating?

    ERIC Educational Resources Information Center

    Jacob, Brian A.; Walsh, Elias

    2011-01-01

    We examine the relationship between the formal ratings that principals give teachers and a variety of observable teacher characteristics, including proxies for productivity. Prior work has shown that principals can differentiate between more and less effective teachers, especially at the tails of the quality distribution, and that subjective…

  8. Understanding Rates of Change.

    ERIC Educational Resources Information Center

    Weil, Aurelia; Russell, Larry

    This paper presents three activities on how to analyze rates of change in real-life situations using TI-83 calculators and computer-based laboratories. Activities include 24 hour temperature data, the temperature of a light bulb, and an M&M toss. Each section contains descriptions of equipment/materials, data collection, and data analysis. The…

  9. Saturn's magnetospheric refresh rate

    NASA Astrophysics Data System (ADS)

    Rymer, A. M.; Mitchell, D. G.; Hill, T. W.; Kronberg, E. A.; Krupp, N.; Jackman, C. M.

    2013-06-01

    A 2-3 day periodicity observed in Jupiter's magnetosphere (superposed on the giant planet's 9.5 h rotation rate) has been associated with a characteristic mass-loading/unloading period at Jupiter. We follow a method derived by Kronberg et al. () and find, consistent with their results, that this period is most likely to fall between 1.5 and 3.9 days. Assuming the same process operates at Saturn, we argue, based on equivalent scales at the two planets, that its period should be 4 to 6 times faster at Saturn and therefore display a period of 8 to 18 h. Applying the method of Kronberg et al. for the mass-loading source rates estimated by Smith et al. () based on data from the third and fifth Cassini-Enceladus encounters, we estimate that the expected magnetospheric refresh rate varies from 8 to 31 h, a range that includes Saturn's rotation rate of ~10.8 h. The magnetospheric period we describe is proportional to the total mass-loading rate in the system. The period is, therefore, faster (1) for increased outgassing from Enceladus, (2) near Saturn solstice (when the highest proportion of the rings is illuminated), and (3) near solar maximum when ionization by solar photons maximizes. We do not claim to explain the few percent jitter in period derived from Saturn Kilometric Radiation with this model, nor do we address the observed difference in period observed in the north and south hemispheres.

  10. Prolonged Adaptation to a Low or High Protein Diet Does Not Modulate Basal Muscle Protein Synthesis Rates - A Substudy.

    PubMed

    Hursel, Rick; Martens, Eveline A P; Gonnissen, Hanne K J; Hamer, Henrike M; Senden, Joan M G; van Loon, Luc J C; Westerterp-Plantenga, Margriet S

    2015-01-01

    Based on controlled 36 h experiments a higher dietary protein intake causes a positive protein balance and a negative fat balance. A positive net protein balance may support fat free mass accrual. However, few data are available on the impact of more prolonged changes in habitual protein intake on whole-body protein metabolism and basal muscle protein synthesis rates. To assess changes in whole-body protein turnover and basal muscle protein synthesis rates following 12 weeks of adaptation to a low versus high dietary protein intake. A randomized parallel study was performed in 40 subjects who followed either a high protein (2.4 g protein/kg/d) or low protein (0.4 g protein/kg/d) energy-balanced diet (30/35/35% or 5/60/35% energy from protein/carbohydrate/fat) for a period of 12 weeks. A subgroup of 7 men and 8 women (body mass index: 22.8±2.3 kg/m2, age: 24.3±4.9 y) were selected to evaluate the impact of prolonged adaptation to either a high or low protein intake on whole body protein metabolism and basal muscle protein synthesis rates. After the diet, subjects received continuous infusions with L-[ring-2H5]phenylalanine and L-[ring-2H2]tyrosine in an overnight fasted state, with blood samples and muscle biopsies being collected to assess post-absorptive whole-body protein turnover and muscle protein synthesis rates in vivo in humans. After 12 weeks of intervention, whole-body protein balance in the fasted state was more negative in the high protein treatment when compared with the low protein treatment (-4.1±0.5 vs -2.7±0.6 μmol phenylalanine/kg/h;P<0.001). Whole-body protein breakdown (43.0±4.4 vs 37.8±3.8 μmol phenylalanine/kg/h;P<0.03), synthesis (38.9±4.2 vs 35.1±3.6 μmol phenylalanine/kg/h;P<0.01) and phenylalanine hydroxylation rates (4.1±0.6 vs 2.7±0.6 μmol phenylalanine/kg/h;P<0.001) were significantly higher in the high vs low protein group. Basal muscle protein synthesis rates were maintained on a low vs high protein diet (0.042±0.01 vs 0

  11. Prolonged Adaptation to a Low or High Protein Diet Does Not Modulate Basal Muscle Protein Synthesis Rates – A Substudy

    PubMed Central

    Hursel, Rick; Martens, Eveline A. P.; Gonnissen, Hanne K. J.; Hamer, Henrike M.; Senden, Joan M. G.; van Loon, Luc J. C.; Westerterp-Plantenga, Margriet S.

    2015-01-01

    Background Based on controlled 36 h experiments a higher dietary protein intake causes a positive protein balance and a negative fat balance. A positive net protein balance may support fat free mass accrual. However, few data are available on the impact of more prolonged changes in habitual protein intake on whole-body protein metabolism and basal muscle protein synthesis rates. Objective To assess changes in whole-body protein turnover and basal muscle protein synthesis rates following 12 weeks of adaptation to a low versus high dietary protein intake. Methods A randomized parallel study was performed in 40 subjects who followed either a high protein (2.4 g protein/kg/d) or low protein (0.4 g protein/kg/d) energy-balanced diet (30/35/35% or 5/60/35% energy from protein/carbohydrate/fat) for a period of 12 weeks. A subgroup of 7 men and 8 women (body mass index: 22.8±2.3 kg/m2, age: 24.3±4.9 y) were selected to evaluate the impact of prolonged adaptation to either a high or low protein intake on whole body protein metabolism and basal muscle protein synthesis rates. After the diet, subjects received continuous infusions with L-[ring-2H5]phenylalanine and L-[ring-2H2]tyrosine in an overnight fasted state, with blood samples and muscle biopsies being collected to assess post-absorptive whole-body protein turnover and muscle protein synthesis rates in vivo in humans. Results After 12 weeks of intervention, whole-body protein balance in the fasted state was more negative in the high protein treatment when compared with the low protein treatment (-4.1±0.5 vs -2.7±0.6 μmol phenylalanine/kg/h;P<0.001). Whole-body protein breakdown (43.0±4.4 vs 37.8±3.8 μmol phenylalanine/kg/h;P<0.03), synthesis (38.9±4.2 vs 35.1±3.6 μmol phenylalanine/kg/h;P<0.01) and phenylalanine hydroxylation rates (4.1±0.6 vs 2.7±0.6 μmol phenylalanine/kg/h;P<0.001) were significantly higher in the high vs low protein group. Basal muscle protein synthesis rates were maintained on a low

  12. Biological evolution model with conditional mutation rates

    NASA Astrophysics Data System (ADS)

    Saakian, David B.; Ghazaryan, Makar; Bratus, Alexander; Hu, Chin-Kun

    2017-05-01

    We consider an evolution model, in which the mutation rates depend on the structure of population: the mutation rates from lower populated sequences to higher populated sequences are reduced. We have applied the Hamilton-Jacobi equation method to solve the model and calculate the mean fitness. We have found that the modulated mutation rates, directed to increase the mean fitness.

  13. The effect of ATP-sensitive potassium channel modulation on heart rate in isolated muskrat and guinea pig hearts.

    PubMed

    Streeby, D R; McKean, T A

    1994-12-01

    Muskrats (Ondontra zibethicus) are common freshwater diving mammals exhibiting a bradycardia with both forced and voluntary diving. This bradycardia is mediated by vagal innervation; however, if hypoxia is present there may be local factors that also decrease heart rate. Some of these local factors may include ATP-sensitive potassium channel activation and extracellular accumulation of potassium ions, hydrogen ions and lactate. The purpose of this study was to investigate the role of these factors in the isolated perfused hearts of muskrats and of a non-diving mammal, the guinea pig. Although lactate and proton administration reduced heart rate in isolated muskrat and guinea pig hearts, there was no difference in the response to lactate and proton infusion between the two species. Muskrat hearts were more sensitive to the heart-rate-lowering effects of exogenously applied potassium than were guinea pig hearts. Early increases in extracellular potassium concentration during hypoxia are thought to be mediated by the ATP-sensitive potassium channel. Activation of these channels under normoxic conditions had a mildly negative chronotropic effect in both species; however, activation of these channels with Lemakalim under hypoxic conditions caused the guinea pig heart to respond with an augmented bradycardia similar to that seen in the hypoxic muskrat heart in the absence of drugs. Inhibition of these channels by glibenclamide during hypoxia was partially successful in blocking the bradycardia in guinea pig hearts, but inhibition of the same channels in hypoxic muskrat hearts had a damaging effect as two of five hearts went into contracture during the hypoxia. Thus, although ATP-sensitive potassium channels appear to have a major role in the bradycardia of hypoxia in guinea pigs, the failure to prevent the bradycardia by inhibition of these channels in muskrat hearts suggests that multiple factors are involved in the hypoxia-induced bradycardia in this species.

  14. Unusual ISS Rate Signature

    NASA Technical Reports Server (NTRS)

    Laible, Michael R.

    2011-01-01

    On November 23, 2011 International Space Station Guidance, Navigation, and Control reported unusual pitch rate disturbance. These disturbances were an order of magnitude greater than nominal rates. The Loads and Dynamics team was asked to review and analyze current accelerometer data to investigate this disturbance. This paper will cover the investigation process under taken by the Loads and Dynamics group. It will detail the accelerometers used and analysis performed. The analysis included performing Frequency Fourier Transform of the data to identify the mode of interest. This frequency data is then reviewed with modal analysis of the ISS system model. Once this analysis is complete and the disturbance quantified, a forcing function was produced to replicate the disturbance. This allows the Loads and Dynamics team to report the load limit values for the 100's of interfaces on the ISS.

  15. Sequoia Messaging Rate Benchmark

    SciTech Connect

    Friedley, Andrew

    2008-01-22

    The purpose of this benchmark is to measure the maximal message rate of a single compute node. The first num_cores ranks are expected to reside on the 'core' compute node for which message rate is being tested. After that, the next num_nbors ranks are neighbors for the first core rank, the next set of num_nbors ranks are neighbors for the second core rank, and so on. For example, testing an 8-core node (num_cores = 8) with 4 neighbors (num_nbors = 4) requires 8 + 8 * 4 - 40 ranks. The first 8 of those 40 ranks are expected to be on the 'core' node being benchmarked, while the rest of the ranks are on separate nodes.

  16. Donation rates: what matters?

    PubMed

    Mizraji, R; Godino, M; Tommasino, N; Alvarez, I

    2014-11-01

    The increase in the number of donors is the main objective of all transplantation organizations around the world. Further understanding of the factors involved in increasing donation rates is very important for planning future strategies to improve outcomes in each country. With this purpose we analyzed the relationship between social and economic factors of the countries and organizational aspects of health systems and institutions dedicated to transplantation in relation to the number of actual donors per million population. We analyzed rates of deceased donors per million population of Latin America, North America, and Europe (20 countries) and correlated them with the human development index and its most important indicators. We also studied the correlation with spending on health and organizational aspects of the health system. On the one hand, we found that donation rates (DRs) per million population (pmp) were not statistically significantly correlated with the human development index (significant correlation 0.61 and 0.181). There is a correlation, albeit weak, between observed donation rates and gross domestic product (GDP) of each country (significance, 0.04; correlation, 0.46). On the other hand, there exists a strong correlation between the percentage of GDP spent on health and DRs pmp (significance, 0.01; correlation, 0.53). Those countries with an integrated national health system (P = .01) and a higher percentage of hospitals with intrahospital transplantation coordinators (P = .001) had higher DRs pmp. The best DRs are closely linked to organizational aspects of the donation system in particular and the health system in general. There is a weak correlation between observed DRs and socio-economic and development indicators of countries. These data should be taken into account in planning future strategies to increase DRs, health plan policies, and investments.

  17. Rotational rate sensor

    DOEpatents

    Hunter, Steven L.

    2002-01-01

    A rate sensor for angular/rotational acceleration includes a housing defining a fluid cavity essentially completely filled with an electrolyte fluid. Within the housing, such as a toroid, ions in the fluid are swept during movement from an excitation electrode toward one of two output electrodes to provide a signal for directional rotation. One or more ground electrodes within the housing serve to neutralize ions, thus preventing any effect at the other output electrode.

  18. Constituents of response rates

    PubMed Central

    Pear, Joseph J.; Rector, Brian L.

    1979-01-01

    Response rate and the proportion of time pigeons allocated to a key-pecking activity were measured on several basic types of reinforcement schedules. Reinforcement frequency was varied within each type of basic schedule, and the effects on two constituents of response rate were noted. Propensity, the proportion of time the birds spent on a platform in front of the key, showed very consistent effects as reinforcement frequency varied: in general, it decreased when reinforcement frequency markedly decreased and it increased when reinforcement frequency increased. Speed, key pecks per unit of time spent on the platform, showed inconsistent effects when reinforcement frequency varied. Consequently, response rate showed less consistent effects than did propensity. Cumulative response records demonstrated the existence of several different types of transitions or boundary states between the key-pecking activity and other activities. The types of transitions that occurred between activities depended on both the type of reinforcement schedule and the frequency of reinforcement. The propensity data support the position that general laws of behavior can be based on temporal measures of behavior. The speed data suggest that, if a complete assessment of the dynamic properties of behavior is to be achieved, measures of behavior must incorporate the structural variations in the operant unit. PMID:16812155

  19. Injection rate control cam

    SciTech Connect

    Perr, J.P.; Liang, E.; Yu, R.C.; Ghuman, A.S.

    1990-10-16

    This patent describes a cam for controlling the injection rate of fuel in a fuel injection system of an engine. The fuel injection system including a cyclically operating unit injector having a body, an injector plunger mounted for reciprocating movement in the injector body between an advanced position and a retracted portion to pump into the engine during each cycle a variable quantity of fuel up to a maximum quantity under rated engine conditions, and a drive train for converting rotational movement of the cam into reciprocating movement of the pumping plunger depending on the profile of the cam. The cam profile comprises at least a plunger retraction segment and a plunger advancement segment for controlling the velocity if injector plunger retraction and advancement, respectively, the plunger advancement segment including a pre-injection subsequent shaped to cause an initial quantity of fuel to be injected into the engine during each cycle at rated engine conditions while the pre-injection subsegment is in contact with the drive train, and an injection subsegment following the pre-injection subsegment.

  20. Increasing rates of depression.

    PubMed

    Klerman, G L; Weissman, M M

    1989-04-21

    Several recent, large epidemiologic and family studies suggest important temporal changes in the rates of major depression: an increase in the rates in the cohorts born after World War II; a decrease in the age of onset with an increase in the late teenaged and early adult years; an increase between 1960 and 1975 in the rates of depression for all ages; a persistent gender effect, with the risk of depression consistently two to three times higher among women than men across all adult ages; a persistent family effect, with the risk about two to three times higher in first-degree relatives as compared with controls; and the suggestion of a narrowing of the differential risk to men and women due to a greater increase in risk of depression among young men. These trends, drawn from studies using comparable methods and modern diagnostic criteria, are evident in the United States, Sweden, Germany, Canada, and New Zealand, but not in comparable studies conducted in Korea and Puerto Rico and of Mexican-Americans living in the United States. These cohort changes cannot be fully attributed to artifacts of reporting, recall, mortality, or labeling and have implications for understanding the etiology of depression and for clinical practice.

  1. Homicide Rates in Lithuania.

    PubMed

    Chmieliauskas, Sigitas; Laima, Sigitas; Andriuskeviciute, Gerda; Jurolaic, Eleonora; Jasulaitis, Algimantas

    2017-08-15

    Homicide rate in Lithuania between 2004 and 2013 decreased and reached an average of 6.7 per 100,000 people in 2013. The data regarding forensic autopsies of intentional homicide victims were obtained from the State Forensic Medicine Service. Spearman's correlation test was used to assess trends in the homicide rates. A significant correlation was observed between homicide distribution and the following variables: Lithuania's gross domestic product (r = -0.85, p = 0.003), the number of alcohol intoxication cases of victims (r = 0.97, p < 0.05). After regression model adjustments, these variables remained significantly associated with the homicide distribution (p < 0.05). 73% of victims were men, with a mean age of 45.5 ± 15. Alcohol intoxication was present in 58% of victims. 66% of homicides were carried out indoors, 57% in urban area. The presented findings help decide which prevention programs may be the most effective in homicide rate reduction. © 2017 American Academy of Forensic Sciences.

  2. Composite rating scales.

    PubMed

    Martinez-Martin, Pablo

    2010-02-15

    Rating scales are instruments that are very frequently used by clinicians to perform patient assessments. Typically, rating scales grade the attribute on an ordinal level of measurement, i.e., a rank ordering, meaning that the numbers assigned to the different ranks (item scores) do not represent 'real numbers' or 'physical magnitudes'. Single-item scales have some advantages, such as simplicity and low respondent burden, but they may also suffer from disadvantages, such as ambiguous score meanings and low responsiveness. Multi-item scales, in contrast, seem more adequate for assessment of complex constructs, allowing for detailed evaluation. Total scores representing the value of the construct may be quite precise and thus the responsiveness of the scale may be high. The most common strategy for obtaining the total score is the sum of the item scores, a strategy that constitutes one of the most important problems with these types of scales. A summative score of ordinal figures is not a 'real magnitude' and may have little sense. This paper is a review of the theoretical frameworks of the main theories used to develop rating scales (Classical Test Theory and Item Response Theory). Bearing in mind that no alternative is perfect, additional research in this field and judicious decisions are called for.

  3. Variable N-terminal regions of muscle myosin heavy chain modulate ATPase rate and actin sliding velocity.

    PubMed

    Swank, Douglas M; Knowles, Aileen F; Kronert, William A; Suggs, Jennifer A; Morrill, George E; Nikkhoy, Massoud; Manipon, Gracielle G; Bernstein, Sanford I

    2003-05-09

    We integratively assessed the function of alternative versions of a region near the N terminus of Drosophila muscle myosin heavy chain (encoded by exon 3a or 3b). We exchanged the alternative exon 3 regions between an embryonic isoform and the indirect flight muscle isoform. Each chimeric myosin was expressed in Drosophila indirect flight muscle, in the absence of other myosin isoforms, allowing for purified protein analysis and whole organism locomotory studies. The flight muscle isoform generates higher in vitro actin sliding velocity and solution ATPase rates than the embryonic isoform. Exchanging the embryonic exon 3 region into the flight muscle isoform decreased ATPase rates to embryonic levels but did not affect actin sliding velocity or flight muscle ultrastructure. Interestingly, this swap only slightly impaired flight ability. Exchanging the flight muscle-specific exon 3 region into the embryonic isoform increased actin sliding velocity 3-fold and improved indirect flight muscle ultrastructure integrity but failed to rescue the flightless phenotype of flies expressing embryonic myosin. These results suggest that the two structural versions of the exon 3 domain independently influence the kinetics of at least two steps of the actomyosin cross-bridge cycle.

  4. Longitudinal Assessment of Global and Regional Rate of Grey Matter Atrophy in 1,172 Healthy Older Adults: Modulation by Sex and Age

    PubMed Central

    Crivello, Fabrice; Tzourio-Mazoyer, Nathalie; Tzourio, Christophe; Mazoyer, Bernard

    2014-01-01

    To characterize the neuroanatomical changes in healthy older adults is important to differentiate pathological from normal brain structural aging. The present study investigated the annualized rate of GM atrophy in a large sample of older participants, focusing on the hippocampus, and searching for modulation by age and sex. In this 4-year longitudinal community cohort study, we used a VBM analysis to estimate the annualized rate of GM loss, at both the global and regional levels, in 1,172 healthy older adults (65–82 years) scanned at 1.5T. The global annualized rate of GM was −4.0 cm3/year (−0.83%/year). The highest rates of regional GM loss were found in the frontal and parietal cortices, middle occipital gyri, temporal cortex and hippocampus. The rate of GM atrophy was higher in women (−4.7 cm3/year, −0.91%/year) than men (−3.3 cm3/year, −0.65%/year). The global annualized rate of GM atrophy remained constant throughout the age range of the cohort, in both sexes. This pattern was replicated at the regional level, with the exception of the hippocampi, which showed a rate of GM atrophy that accelerated with age (2.8%/year per year of age) similarly for men and women. The present study reports a global and regional description of the annualized rate of grey matter loss and its evolution after the age of 65. Our results suggest greater anatomical vulnerability of women in late life and highlight a specific vulnerability of the hippocampus to the aging processes after 65 years of age. PMID:25469789

  5. Certainty rating in pre-and post-tests of study modules in an online clinical pharmacy course - A pilot study to evaluate teaching and learning.

    PubMed

    Luetsch, Karen; Burrows, Judith

    2016-10-14

    Graduate and post-graduate education for health professionals is increasingly delivered in an e-learning environment, where automated, continuous formative testing with integrated feedback can guide students' self-assessment and learning. Asking students to rate the certainty they assign to the correctness of their answers to test questions can potentially provide deeper insights into the success of teaching, with test results informing course designers whether learning outcomes have been achieved. It may also have implications for decision making in clinical practice. A study of pre-and post-tests for five study modules was designed to evaluate the teaching and learning within a pharmacotherapeutic course in an online postgraduate clinical pharmacy program. Certainty based marking of multiple choice questions (MCQ) was adapted for formative pre- and post-study module testing by asking students to rate their certainty of correctness of MCQ answers. Paired t-tests and a coding scheme were used to analyse changes in answers and certainty between pre-and post-tests. A survey evaluated students' experience with the novel formative testing design. Twenty-nine pharmacists enrolled in the postgraduate program participated in the study. Overall 1315 matched pairs of MCQ answers and certainty ratings between pre- and post-module tests were available for evaluation. Most students identified correct answers in post-tests and increased their certainty compared to pre-tests. Evaluation of certainty ratings in addition to correctness of answers identified MCQs and topic areas for revision to course designers. A survey of students showed that assigning certainty ratings to their answers assisted in structuring and focusing their learning throughout online study modules, facilitating identification of areas of uncertainty and gaps in their clinical knowledge. Adding certainty ratings to MCQ answers seems to engage students with formative testing and feedback and focus their

  6. Dual Brushless Resolver Rate Sensor

    NASA Technical Reports Server (NTRS)

    Howard, David E. (Inventor)

    1997-01-01

    A resolver rate sensor is disclosed in which dual brushless resolvers are mechanically coupled to the same output shaft. Diverse inputs are provided to each resolver by providing the first resolver with a DC input and the second resolver with an AC sinusoidal input. A trigonometric identity in which the sum of the squares of the sin and cosine components equal one is used to advantage in providing a sensor of increased accuracy. The first resolver may have a fixed or variable DC input to permit dynamic adjustment of resolver sensitivity thus permitting a wide range of coverage. In one embodiment of the invention the outputs of the first resolver are directly inputted into two separate multipliers and the outputs of the second resolver are inputted into the two separate multipliers, after being demodulated in a pair of demodulator circuits. The multiplied signals are then added in an adder circuit to provide a directional sensitive output. In another embodiment the outputs from the first resolver is modulated in separate modulator circuits and the output from the modulator circuits are used to excite the second resolver. The outputs from the second resolver are demodulated in separate demodulator circuit and added in an adder circuit to provide a direction sensitive rate output.

  7. Exhaustive endurance training for 6-9 weeks did not induce changes in intrinsic heart rate and cardiac autonomic modulation in female athletes.

    PubMed

    Uusitalo, A L; Uusitalo, A J; Rusko, H K

    1998-11-01

    We investigated the effects of progressively increased training load and overtraining on resting and intrinsic heart rate (IHR) and cardiac autonomic modulation (CAM), and their relationships to performance variables. Nine athletes (ETG) increased training volume at 70-90% of maximal oxygen uptake (VO2max) by 130% (p<0.01) and training volume at <70% VO2max by 100% (p < 0.01) during 6-9 weeks. The corresponding increases in six female control athletes (CG) were 5 and 10%. Pharmacological blocking through atropine and propranolol and the Rosenblueth and Simeone model were used to calculate the sympathovagal balance index (Abal) and to measure IHR. The results were analysed using two-way analysis of variance. VO2max, IHR and Abal did not change. Resting heart rate had a tendency to decrease in the ETG and increase in the CG during the training period (interaction p < 0.01). Five ETG athletes demonstrated overtraining state (OA subgroup). Their VO2max (mean+/-SEM) decreased from 53.0+/-2.2 ml x kg(-1) x min(-1) to 50.2+/-2.3 ml x kg(-1) x min(-1) (p < 0.01), but no changes in resting HR, IHR and Abal were found. A significant correlation between the baseline values of VO2max and the parasympathetic activity index was found (r=-0.59, p < 0.05). In conclusion, progressively increased training load and overtraining did not induce significant changes in intrinsic heart rate or cardiac autonomic modulation in female endurance athletes. Resting heart rate rather decreased with heavy endurance training and overtraining. High maximal oxygen uptake was correlated with high cardiac parasympathetic modulation.

  8. Compendium of photovoltaic degradation rates: Photovoltaic degradation rates

    SciTech Connect

    Jordan, Dirk C.; Kurtz, Sarah R.; VanSant, Kaitlyn; Newmiller, Jeff

    2016-02-07

    Published data on photovoltaic (PV) degradation measurements were aggregated and re-examined. The subject has seen an increased interest in recent years resulting in more than 11 000 degradation rates in almost 200 studies from 40 different countries. As studies have grown in number and size, we found an impact from sampling bias attributable to size and accuracy. Because of the correlational nature of this study we examined the data in several ways to minimize this bias. We found median degradation for x-Si technologies in the 0.5-0.6%/year range with the mean in the 0.8-0.9%/year range. Hetero-interface technology (HIT) and microcrystalline silicon (..mu..c-Si) technologies, although not as plentiful, exhibit degradation around 1%/year and resemble thin-film products more closely than x-Si. Several studies showing low degradation for copper indium gallium selenide (CIGS) have emerged. Higher degradation for cadmium telluride (CdTe) has been reported, but these findings could reflect a convolution of less accurate studies and longer stabilization periods for some products. Significant deviations for beginning-of-life measurements with respect to nameplate rating have been documented over the last 35 years. Therefore, degradation rates that use nameplate rating as reference may be significantly impacted. Studies that used nameplate rating as reference but used solar simulators showed less variation than similar studies using outdoor measurements, even when accounting for different climates. This could be associated with confounding effects of measurement uncertainty and soiling that take place outdoors. Hotter climates and mounting configurations that lead to sustained higher temperatures may lead to higher degradation in some, but not all, products. Wear-out non-linearities for the worst performing modules have been documented in a few select studies that took multiple measurements of an ensemble of modules during the lifetime of the system. However, the majority

  9. Poincaré plot indexes of heart rate variability detect dynamic autonomic modulation during general anesthesia induction.

    PubMed

    Hsu, Che-Hao; Tsai, Ming-Ya; Huang, Go-Shine; Lin, Tso-Chou; Chen, Kuen-Pao; Ho, Shung-Tai; Shyu, Liang-Yu; Li, Chi-Yuan

    2012-03-01

    Beat-to-beat heart rate variability (HRV) is caused by the fluctuating balance of sympathetic and parasympathetic tone. The Poincaré plot has been used to evaluate HRV. In this study, we validate that this new method may qualitatively and quantitatively assess the sympathovagal fluctuation in patients during induction of anesthesia with sevoflurane. Twenty-eight young patients were allocated for the study. The patients received a tilt test and on the next day they sustained anesthesia induced with inhaled anesthetics. Electrocardiography signals from the patients were relayed to an analogue-digital converter. The Poincaré plot is quantified by measuring SD1, SD2, and SD1/SD2. Power spectral analyses were performed and LF, HF and HF/LF were calculated. The LF power and the SD2 of the Poincaré plot increased while subjects were tilt-up from the supine position. Additionally, a significant correlation were found between LF and SD2, HF and SD1 (p < 0.05), and LF/HF and SD2/SD1 (p < 0.01). Sevoflurane inhalation for 10 minutes had no effect on heart rate, but diminished LF, total power and SD1, SD2 of the Poincaré plot respectively. However, the LF, SD2 and LF/HF increased; the HF, SD1 and SD1/SD2 ratio decreased after intubation stimulation. Poincaré plot and power spectral analysis of HRV during tilt test and sevoflurane induction significantly correlate. Poincaré plot analysis is easier and more sensitive at evaluating the sympathovagal balance and observing the beat-to-beat HRV. Copyright © 2012. Published by Elsevier B.V.

  10. Reduced Heart Rate Volatility

    PubMed Central

    Grogan, Eric L.; Morris, John A.; Norris, Patrick R.; France, Daniel J.; Ozdas, Asli; Stiles, Renée A.; Harris, Paul A.; Dawant, Benoit M.; Speroff, Theodore

    2004-01-01

    Objective: To determine if using dense data capture to measure heart rate volatility (standard deviation) measured in 5-minute intervals predicts death. Background: Fundamental approaches to assessing vital signs in the critically ill have changed little since the early 1900s. Our prior work in this area has demonstrated the utility of densely sampled data and, in particular, heart rate volatility over the entire patient stay, for predicting death and prolonged ventilation. Methods: Approximately 120 million heart rate data points were prospectively collected and archived from 1316 trauma ICU patients over 30 months. Data were sampled every 1 to 4 seconds, stored in a relational database, linked to outcome data, and de-identified. HR standard deviation was continuously computed over 5-minute intervals (CVRD, cardiac volatility–related dysfunction). Logistic regression models incorporating age and injury severity score were developed on a test set of patients (N = 923), and prospectively analyzed in a distinct validation set (N = 393) for the first 24 hours of ICU data. Results: Distribution of CVRD varied by survival in the test set. Prospective evaluation of the model in the validation set gave an area in the receiver operating curve of 0.81 with a sensitivity and specificity of 70.1 and 80.0, respectively. CVRD predict death as early as 24 hours in the validation set. Conclusions: CVRD identifies a subgroup of patients with a high probability of dying. Death is predicted within first 24 hours of stay. We hypothesize CVRD is a surrogate for autonomic nervous system dysfunction. PMID:15319726

  11. Considerations for How to Rate CPV

    SciTech Connect

    Kurtz, S.; Miller, M.; Marion, B.; Emery, K.; McConnell, R.; Surendran, S.; Kimber, A.

    2011-02-01

    The concentrator photovoltaic (CPV) industry is introducing multiple products into the marketplace, but, as yet, the; community has not embraced a unified method for assessing a nameplate rating. The choices of whether to use 850,; 900, or 1000 W/m2 for the direct-normal irradiance and whether to link the rating to ambient or cell temperature will; affect how CPV modules are rated and compared with other technologies. This paper explores the qualitative and; quantitative ramifications of these choices using data from two multi-junction CPV modules and two flat-plate; modules.

  12. Clinical rating scales.

    PubMed

    Relja, Maja

    2012-01-01

    In Parkinson's disease (PD), rating scales are used to assess the degree of disease-related disability and to titrate long-term treatment to each phase of the disease. Recognition of non-motor symptoms required modification of existing widely used scales to integrate non-motor elements. In addition, new scales have been developed for the assessment of non-motor symptoms. In this article, assessment of PD patients will be discussed, particularly for non-motor symptoms such as pain and fatigue. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. PULSE RATE DIVIDER

    DOEpatents

    McDonald, H.C. Jr.

    1962-12-18

    A compact pulse-rate divider circuit affording low impedance output and high input pulse repetition rates is described. The circuit features a single secondary emission tube having a capacitor interposed between its dynode and its control grid. An output pulse is produced at the anode of the tube each time an incoming pulse at the control grid drives the tube above cutoff and the duration of each output pulse corresponds to the charging time of the capacitor. Pulses incoming during the time the grid bias established by the discharging capacitor is sufficiently negative that the pulses are unable to drive the tube above cutoff do not produce output pulses at the anode; these pulses are lost and a dividing action is thus produced by the circuit. The time constant of the discharge path may be vanied to vary in turn the division ratio of the circuit; the time constant of the charging circuit may be varied to vary the width of the output pulses. (AEC)

  14. Photovoltaic Degradation Rates -- An Analytical Review

    SciTech Connect

    Jordan, D. C.; Kurtz, S. R.

    2012-06-01

    As photovoltaic penetration of the power grid increases, accurate predictions of return on investment require accurate prediction of decreased power output over time. Degradation rates must be known in order to predict power delivery. This article reviews degradation rates of flat-plate terrestrial modules and systems reported in published literature from field testing throughout the last 40 years. Nearly 2000 degradation rates, measured on individual modules or entire systems, have been assembled from the literature, showing a median value of 0.5%/year. The review consists of three parts: a brief historical outline, an analytical summary of degradation rates, and a detailed bibliography partitioned by technology.

  15. Operation of low-noise single-gap RPC modules exposed to ionisation rates up to 1 kHz /cm2

    NASA Astrophysics Data System (ADS)

    Ćwiok, M.; Dominik, W.; Górski, M.; Królikowski, J.

    2004-11-01

    Two single gap medium-size RPC modules, made of bakelite plates of very good mechanical quality of the surface and having initial volume resistivity of 1 ×1010 Ω cm, were tested in the Gamma Irradiation Facility at CERN at ionisation rates up to 1 kHz /cm2. The internal surfaces facing the gas volume of one RPC module were cladded with a thin layer of linseed oil varnish for comparison of oiled and non-oiled RPC operation. The results refer to the gas mixture of C2H2F4/isobutane (97:3) with SF6 addition below 1%. The single gap modules exhibited full detection efficiency plateau for the high voltage range of about 1 kV at full intensity of gamma rays. Good timing characteristics allowed to reach 95% efficiency at fully opened irradiation source with time window of 20 ns. The intrinsic noise rate for a non-oiled and an oiled RPC gap was, respectively, below 5 and 1 Hz /cm2 at full efficiency over 1 kV voltage range.

  16. 77 FR 20476 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-04

    ... ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional... guaranteed fluctuating interest rate SBA loans. This rate will be 2.250 (2 \\1/4\\) percent for the April-June quarter of FY 2012. Pursuant to 13 CFR 120.921(b), the maximum legal interest rate for any third party...

  17. 75 FR 17453 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-06

    ... ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional... guaranteed fluctuating interest rate SBA loans. This rate will be 4.000 (4) percent for the April-June quarter of FY 2010. Pursuant to 13 CFR 120.921(b), the maximum legal interest rate for any third party...

  18. 75 FR 37872 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-30

    ... ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional... guaranteed fluctuating interest rate SBA loans. This rate will be 4.000 (4) percent for the July-September quarter of FY 2010. Pursuant to 13 CFR 120.921(b), the maximum legal interest rate for any third party...

  19. 77 FR 39560 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-03

    ... ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional... guaranteed fluctuating interest rate SBA loans. This rate will be 2.500 (2\\1/2\\) percent for the July-September quarter of FY 2012. Pursuant to 13 CFR 120.921(b), the maximum legal interest rate for any third...

  20. 78 FR 18664 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-27

    ... ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional... guaranteed fluctuating interest rate SBA loans. This rate will be 2.500 (2\\1/2\\) percent for the April-June quarter of FY 2013. Pursuant to 13 CFR 120.921(b), the maximum legal interest rate for any third party...

  1. 75 FR 81326 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-27

    ... ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional... guaranteed fluctuating interest rate SBA loans. This rate will be 3.000 (3) percent for the January-March quarter of FY 2011. Pursuant to 13 CFR 120.921(b), the maximum legal interest rate for any third party...

  2. 76 FR 18821 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-05

    ... ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional... guaranteed fluctuating interest rate SBA loans. This rate will be 3.750 (3\\3/4\\) percent for the April-June quarter of FY 2011. Pursuant to 13 CFR 120.921(b), the maximum legal interest rate for any third party...

  3. 76 FR 38717 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-01

    ... ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional... guaranteed fluctuating interest rate SBA loans. This ] rate will be 3.625 (3\\5/8\\) percent for the July-September quarter of FY 2011. Pursuant to 13 CFR 120.921(b), the maximum legal interest rate for any third...

  4. 76 FR 77581 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-13

    ... ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional... guaranteed fluctuating interest rate SBA loans. This rate will be 2.375 (2\\3/8\\) percent for the January-March quarter of FY 2012. Pursuant to 13 CFR 120.921(b), the maximum legal interest rate for any third...

  5. 78 FR 62932 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-22

    ... ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional... guaranteed fluctuating interest rate SBA loans. This rate will be 3.125 (3\\1/8\\) percent for the October-December quarter of FY 2014. Pursuant to 13 CFR 120.921(b), the maximum legal interest rate for any third...

  6. 75 FR 60152 - Interest Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-29

    ... ADMINISTRATION Interest Rates The Small Business Administration publishes an interest rate called the optional... guaranteed fluctuating interest rate SBA loans. This rate will be 3.250 (3\\1/4\\) percent for the October-December quarter of FY 2011. Pursuant to 13 CFR 120.921(b), the maximum legal interest rate for any third...

  7. Experimental warming and precipitation interactively modulate the mortality rate and timing of spring emergence of a gallmaking Tephritid fly

    PubMed Central

    Xi, Xinqiang; Li, Dongbo; Peng, Youhong; Eisenhauer, Nico; Sun, Shucun

    2016-01-01

    Global climate change is mostly characterized by temperature increase and fluctuating precipitation events, which may affect the spring phenology and mortality rate of insects. However, the interaction effect of temperature and precipitation on species performance has rarely been examined. Here we studied the response of the gall-making Tephritid fly Urophora stylata (Diptera: Tephritidae) to artificial warming, changes in precipitation, and the presence of galls. Our results revealed a significant interaction effect of warming, precipitation, and galls on the life-history traits of the focal species. Specifically, when the galls were intact, warming had no effect on the phenology and increased the mortality of the fly under decreased precipitation, but it significantly advanced the timing of adult emergence and had no effect on the mortality under increased precipitation. When galls were removed, warming significantly advanced the timing of emergence and increased fly mortality, but precipitation showed no effect on the phenology and mortality. In addition, gall removal significantly increased adult fresh mass for both females and males. Our results indicate that the effect of elevated temperature on the performance of species may depend on other environmental conditions, such as variations in precipitation, and species traits like the formation of galls. PMID:27578601

  8. Experimental warming and precipitation interactively modulate the mortality rate and timing of spring emergence of a gallmaking Tephritid fly

    NASA Astrophysics Data System (ADS)

    Xi, Xinqiang; Li, Dongbo; Peng, Youhong; Eisenhauer, Nico; Sun, Shucun

    2016-08-01

    Global climate change is mostly characterized by temperature increase and fluctuating precipitation events, which may affect the spring phenology and mortality rate of insects. However, the interaction effect of temperature and precipitation on species performance has rarely been examined. Here we studied the response of the gall-making Tephritid fly Urophora stylata (Diptera: Tephritidae) to artificial warming, changes in precipitation, and the presence of galls. Our results revealed a significant interaction effect of warming, precipitation, and galls on the life-history traits of the focal species. Specifically, when the galls were intact, warming had no effect on the phenology and increased the mortality of the fly under decreased precipitation, but it significantly advanced the timing of adult emergence and had no effect on the mortality under increased precipitation. When galls were removed, warming significantly advanced the timing of emergence and increased fly mortality, but precipitation showed no effect on the phenology and mortality. In addition, gall removal significantly increased adult fresh mass for both females and males. Our results indicate that the effect of elevated temperature on the performance of species may depend on other environmental conditions, such as variations in precipitation, and species traits like the formation of galls.

  9. Modulation of the reaction rate of regulating protein induces large morphological and motional change of amoebic cell.

    PubMed

    Nishimura, Shin I; Sasai, Masaki

    2007-03-21

    Morphologies of moving amoebae are categorized into two types. One is the "neutrophil" type in which the long axis of cell roughly coincides with its moving direction. This type of cell extends a leading edge at the front and retracts a narrow tail at the rear, whose shape has been often drawn as a typical amoeba in textbooks. The other one is the "keratocyte" type with widespread lamellipodia along the front side arc. Short axis of cell in this type roughly coincides with its moving direction. In order to understand what kind of molecular feature causes conversion between two types of morphologies, and how two typical morphologies are maintained, a mathematical model of amoebic cells is developed. This model describes movement of cell and intracellular reactions of activator, inhibitor and actin filaments in a unified way. It is found that the producing rate of activator is a key factor of conversion between two types. This model also explains the observed data that the keratocyte type cells tend to rapidly move along a straight line. The neutrophil type cells move along a straight line when the moving velocity is small, but they show fluctuated motions deviating from a line when they move as fast as the keratocyte type cells. Efficient energy consumption in the neutrophil type cells is predicted.

  10. Estrogen regulates the rate of bone turnover but bone balance in ovariectomized rats is modulated by prevailing mechanical strain

    NASA Technical Reports Server (NTRS)

    Westerlind, K. C.; Wronski, T. J.; Ritman, E. L.; Luo, Z. P.; An, K. N.; Bell, N. H.; Turner, R. T.

    1997-01-01

    Estrogen deficiency induced bone loss is associated with increased bone turnover in rats and humans. The respective roles of increased bone turnover and altered balance between bone formation and bone resorption in mediating estrogen deficiency-induced cancellous bone loss was investigated in ovariectomized rats. Ovariectomy resulted in increased bone turnover in the distal femur. However, cancellous bone was preferentially lost in the metaphysis, a site that normally experiences low strain energy. No bone loss was observed in the epiphysis, a site experiencing higher strain energy. The role of mechanical strain in maintaining bone balance was investigated by altering the strain history. Mechanical strain was increased and decreased in long bones of ovariectomized rats by treadmill exercise and functional unloading, respectively. Functional unloading was achieved during orbital spaceflight and following unilateral sciatic neurotomy. Increasing mechanical loading reduced bone loss in the metaphysis. In contrast, decreasing loading accentuated bone loss in the metaphysis and resulted in bone loss in the epiphysis. Finally, administration of estrogen to ovariectomized rats reduced bone loss in the unloaded and prevented loss in the loaded limb following unilateral sciatic neurotomy in part by reducing indices of bone turnover. These results suggest that estrogen regulates the rate of bone turnover, but the overall balance between bone formation and bone resorption is influenced by prevailing levels of mechanical strain.

  11. Experimental warming and precipitation interactively modulate the mortality rate and timing of spring emergence of a gallmaking Tephritid fly.

    PubMed

    Xi, Xinqiang; Li, Dongbo; Peng, Youhong; Eisenhauer, Nico; Sun, Shucun

    2016-08-31

    Global climate change is mostly characterized by temperature increase and fluctuating precipitation events, which may affect the spring phenology and mortality rate of insects. However, the interaction effect of temperature and precipitation on species performance has rarely been examined. Here we studied the response of the gall-making Tephritid fly Urophora stylata (Diptera: Tephritidae) to artificial warming, changes in precipitation, and the presence of galls. Our results revealed a significant interaction effect of warming, precipitation, and galls on the life-history traits of the focal species. Specifically, when the galls were intact, warming had no effect on the phenology and increased the mortality of the fly under decreased precipitation, but it significantly advanced the timing of adult emergence and had no effect on the mortality under increased precipitation. When galls were removed, warming significantly advanced the timing of emergence and increased fly mortality, but precipitation showed no effect on the phenology and mortality. In addition, gall removal significantly increased adult fresh mass for both females and males. Our results indicate that the effect of elevated temperature on the performance of species may depend on other environmental conditions, such as variations in precipitation, and species traits like the formation of galls.

  12. Frequency-dependent reduction of voltage-gated sodium current modulates retinal ganglion cell response rate to electrical stimulation

    NASA Astrophysics Data System (ADS)

    Tsai, David; Morley, John W.; Suaning, Gregg J.; Lovell, Nigel H.

    2011-10-01

    The ability to elicit visual percepts through electrical stimulation of the retina has prompted numerous investigations examining the feasibility of restoring sight to the blind with retinal implants. The therapeutic efficacy of these devices will be strongly influenced by their ability to elicit neural responses that approximate those of normal vision. Retinal ganglion cells (RGCs) can fire spikes at frequencies greater than 200 Hz when driven by light. However, several studies using isolated retinas have found a decline in RGC spiking response rate when these cells were stimulated at greater than 50 Hz. It is possible that the mechanism responsible for this decline also contributes to the frequency-dependent 'fading' of electrically evoked percepts recently reported in human patients. Using whole-cell patch clamp recordings of rabbit RGCs, we investigated the causes for the spiking response depression during direct subretinal stimulation of these cells at 50-200 Hz. The response depression was not caused by inhibition arising from the retinal network but, instead, by a stimulus-frequency-dependent decline of RGC voltage-gated sodium current. Under identical experimental conditions, however, RGCs were able to spike at high frequency when driven by light stimuli and intracellular depolarization. Based on these observations, we demonstrated a technique to prevent the spiking response depression.

  13. Assessment of cardiac autonomic modulation during graded head-up tilt by symbolic analysis of heart rate variability.

    PubMed

    Porta, Alberto; Tobaldini, Eleonora; Guzzetti, Stefano; Furlan, Raffaello; Montano, Nicola; Gnecchi-Ruscone, Tomaso

    2007-07-01

    Two symbolic indexes, the percentage of sequences characterized by three heart periods with no significant variations (0V%) and that with two significant unlike variations (2UV%), have been found to reflect changes in sympathetic and vagal modulations, respectively. We tested the hypothesis that symbolic indexes may track the gradual shift of the cardiac autonomic modulation during an incremental head-up tilt test. Symbolic analysis was carried out over heart period variability series (250 cardiac beats) derived from ECG recordings during a graded head-up tilt test (0, 15, 30, 45, 60, 75, and 90 degrees ) in 17 healthy subjects. The percentage of subjects showing a significant linear correlation (Spearman rank-order correlation) with tilt angles was utilized to evaluate the performance of symbolic analysis. Spectral analysis was carried out for comparison over the same series. 0V% progressively increased with tilt angles, whereas 2UV% gradually decreased. The decline of 2UV% was greater than the increase of 0V% at low tilt angles. Linear correlation with tilt angles was exhibited in a greater percentage of subjects for 0V% and 2UV% than for any spectral index. Our findings suggest that symbolic analysis performed better than spectral analysis and, thus, is a suitable methodology for assessment of the subtle changes of cardiac autonomic modulation induced by a graded head-up tilt test. Moreover, symbolic analysis indicates that the changes of cardiac sympathetic and vagal modulations observed during this protocol were reciprocal but characterized by different absolute magnitudes.

  14. Lindblad rate equations

    SciTech Connect

    Budini, Adrian A.

    2006-11-15

    In this paper we derive an extra class of non-Markovian master equations where the system state is written as a sum of auxiliary matrixes whose evolution involve Lindblad contributions with local coupling between all of them, resembling the structure of a classical rate equation. The system dynamics may develop strong nonlocal effects such as the dependence of the stationary properties with the system initialization. These equations are derived from alternative microscopic interactions, such as complex environments described in a generalized Born-Markov approximation and tripartite system-environment interactions, where extra unobserved degrees of freedom mediates the entanglement between the system and a Markovian reservoir. Conditions that guarantee the completely positive condition of the solution map are found. Quantum stochastic processes that recover the system dynamics in average are formulated. We exemplify our results by analyzing the dynamical action of nontrivial structured dephasing and depolarizing reservoirs over a single qubit.

  15. Vital Signs Rate Meter.

    DTIC Science & Technology

    1987-09-01

    S15 VITAL SIGNS RTE NETER(U) TEXAS R FW4D A UNIV COLLEGE 1/1 STATION IENGINEERING PROGM C S LESSAD ET RL. SEP 8? USRFSN-TR-$?-14 F33615-S3-D-0602...UNCLMSIFIED F/O 6/12 ML IIB 125 11 128 11.2.5_ ka7 U S S SS S S S S S0 02.2 36 * . * * * . - * . - .. . - - . Q -- .* USAFSAM-TR-87-1 4 VITAL SIGNS RATE...UNIT ELEMENT NO. INO.I NO. IACESSION NO. 622027 2729 02 21 11 TITLE ft ml’S111111:1111"ll vital Signs Rae ~t= 12. PERSONAL AUTWOR(S) Lessard, Cierles

  16. All about Heart Rate (Pulse)

    MedlinePlus

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More All About Heart Rate (Pulse) Updated:Aug 22,2017 ... Blood Pressure is Diagnosed BP vs. Heart Rate All About Heart Rate (Pulse) Low Blood Pressure Resistant ...

  17. Psychrophilic (6--15 {degree}C) high-rate anaerobic treatment of malting wastewater in a two-module expanded granular sludge bed system

    SciTech Connect

    Rebac, S.; Lier, J.B. van; Lens, P.; Cappellen, J. van; Vermeulen, M.; Stams, A.J.M.; Lettinga, G.; Dekkers, F.; Swinkels, K.T.M.

    1998-11-01

    Psychrophilic (6--15 C) anaerobic treatment of malting wastewater was investigated. A two-module expanded granular sludge bed reactor system with a total volume of 140 dm{sup 3} was used to treat malting wastewater having a soluble and total chemical oxygen demand (COD) between 233 and 1778 mg dm{sup {minus}3} and between 317 and 4422 mg dm{sup {minus}3}, respectively. The removal efficiencies at 6 C were 47 and 71% of the soluble and volatile fatty acids (VFA) COD, at organic loading rates (OLR) ranging between 3.3 and 5.8 kg of COD m{sup {minus}3} day{sup {minus}1}. The removal efficiencies at 10--15 C were 67--78 and 90--96% of the soluble and VFA COD at an OLR between 2.8 and 12.3 kg of COD m{sup {minus}3} day{sup {minus}1}. The specific methanogenic activity of the sludge present in each module increased 2--3-fold during system operation for 400 days. The relatively high concentration of suspended solids in the influent (25% of the total COD) caused a deterioration of the sludge bed in the first reactor module. This was aggravated by excessive growth of acidifying biomass, which persisted in the first module sludge bed and resulted in granular sludge flotation. However, the second module could accommodate the increased OLR, this providing a very high effluent quality (soluble COD < 200 mg dm{sup {minus}3}) of the total system. The stability of module 1 concerning suspended solids could be restored by presettling the wastewater.

  18. Iron oxide nanoparticle agglomeration influences dose rates and modulates oxidative stress-mediated dose–response profiles in vitro

    PubMed Central

    Sharma, Gaurav; Kodali, Vamsi; Gaffrey, Matthew; Wang, Wei; Minard, Kevin R.; Karin, Norman J.; Teeguarden, Justin G.; Thrall, Brian D.

    2014-01-01

    Spontaneous agglomeration of engineered nanoparticles (ENPs) is a common problem in cell culture media which can confound interpretation of in vitro nanotoxicity studies. The authors created stable agglomerates of iron oxide nanoparticles (IONPs) in conventional culture medium, which varied in hydrodynamic size (276 nm–1.5 μm) but were composed of identical primary particles with similar surface potentials and protein coatings. Studies using C10 lung epithelial cells show that the dose rate effects of agglomeration can be substantial, varying by over an order of magnitude difference in cellular dose in some cases. Quantification by magnetic particle detection showed that small agglomerates of carboxylated IONPs induced greater cytotoxicity and redox-regulated gene expression when compared with large agglomerates on an equivalent total cellular IONP mass dose basis, whereas agglomerates of amine-modified IONPs failed to induce cytotoxicity or redox-regulated gene expression despite delivery of similar cellular doses. Dosimetry modelling and experimental measurements reveal that on a delivered surface area basis, large and small agglomerates of carboxylated IONPs have similar inherent potency for the generation of ROS, induction of stress-related genes and eventual cytotoxicity. The results suggest that reactive moieties on the agglomerate surface are more efficient in catalysing cellular ROS production than molecules buried within the agglomerate core. Because of the dynamic, size and density-dependent nature of ENP delivery to cells in vitro, the biological consequences of agglomeration are not discernible from static measures of exposure concentration (μg/ml) alone, highlighting the central importance of integrated physical characterisation and quantitative dosimetry for in vitro studies. The combined experimental and computational approach provides a quantitative framework for evaluating relationships between the biocompatibility of nanoparticles and their

  19. Towards Stable Lithium-Sulfur Batteries with a Low Self-Discharge Rate: Ion Diffusion Modulation and Anode Protection.

    PubMed

    Xu, Wen-Tao; Peng, Hong-Jie; Huang, Jia-Qi; Zhao, Chen-Zi; Cheng, Xin-Bing; Zhang, Qiang

    2015-09-07

    The self-discharge of a lithium-sulfur cell decreases the shelf-life of the battery and is one of the bottlenecks that hinders its practical applications. New insights into both the internal chemical reactions in a lithium-sulfur system and effective routes to retard self-discharge for highly stable batteries are crucial for the design of lithium-sulfur cells. Herein, a lithium-sulfur cell with a carbon nanotube/sulfur cathode and lithium-metal anode in lithium bis(trifluoromethanesulfonyl)imide/1,3-dioxolane/dimethyl ether electrolyte was selected as the model system to investigate the self-discharge behavior. Both lithium anode passivation and polysulfide anion diffusion suppression strategies are applied to reduce self-discharge of the lithium-sulfur cell. When the lithium-metal anode is protected by a high density passivation layer induced by LiNO3 , a very low shuttle constant of 0.017 h(-1) is achieved. The diffusion of the polysulfides is retarded by an ion-selective separator, and the shuttle constants decreased. The cell with LiNO3 additive maintained a discharge capacity of 97 % (961 mAh g(-1) ) of the initial capacity after 120 days at open circuit, which was around three times higher than the routine cell (32 % of initial capacity, corresponding to 320 mAh g(-1) ). It is expected that lithium-sulfur batteries with ultralow self-discharge rates may be fabricated through a combination of anode passivation and polysulfide shuttle control, as well as optimization of the lithium-sulfur cell configuration. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Iron Oxide Nanoparticle Agglomeration Influences Dose-Rates and Modulates Oxidative Stress Mediated Dose-Response Profiles In Vitro

    SciTech Connect

    Sharma, Gaurav; Kodali, Vamsi K.; Gaffrey, Matthew J.; Wang, Wei; Minard, Kevin R.; Karin, Norman J.; Teeguarden, Justin G.; Thrall, Brian D.

    2013-07-31

    Spontaneous agglomeration of engineered nanoparticles (ENPs) is a common problem in cell culture media which can confound interpretation of in vitro nanotoxicity studies. The authors created stable agglomerates of iron oxide nanoparticles (IONPs) in conventional culture medium, which varied in hydrodynamic size (276 nm-1.5 μm) but were composed of identical primary particles with similar surface potentials and protein coatings. Studies using C10 lung epithelial cells show that the dose rate effects of agglomeration can be substantial, varying by over an order of magnitude difference in cellular dose in some cases. Quantification by magnetic particle detection showed that small agglomerates of carboxylated IONPs induced greater cytotoxicity and redox-regulated gene expression when compared with large agglomerates on an equivalent total cellular IONP mass dose basis, whereas agglomerates of amine-modified IONPs failed to induce cytotoxicity or redox-regulated gene expression despite delivery of similar cellular doses. Dosimetry modelling and experimental measurements reveal that on a delivered surface area basis, large and small agglomerates of carboxylated IONPs have similar inherent potency for the generation of ROS, induction of stress-related genes and eventual cytotoxicity. The results suggest that reactive moieties on the agglomerate surface are more efficient in catalysing cellular ROS production than molecules buried within the agglomerate core. Because of the dynamic, size and density-dependent nature of ENP delivery to cells in vitro, the biological consequences of agglomeration are not discernible from static measures of exposure concentration (μg/ml) alone, highlighting the central importance of integrated physical characterisation and quantitative dosimetry for in vitro studies. The combined experimental and computational approach provides a quantitative framework for evaluating relationships between the biocompatibility of nanoparticles and their

  1. Perception of a sung vowel as a function of frequency-modulation rate and excursion in listeners with normal hearing and hearing impairment.

    PubMed

    Vatti, Marianna; Santurette, Sébastien; Pontoppidan, Niels Henrik; Dau, Torsten

    2014-10-01

    Frequency fluctuations in human voices can usually be described as coherent frequency modulation (FM). As listeners with hearing impairment (HI listeners) are typically less sensitive to FM than listeners with normal hearing (NH listeners), this study investigated whether hearing loss affects the perception of a sung vowel based on FM cues. Vibrato maps were obtained in 14 NH and 12 HI listeners with different degrees of musical experience. The FM rate and FM excursion of a synthesized vowel, to which coherent FM was applied, were adjusted until a singing voice emerged. In NH listeners, adding FM to the steady vowel components produced perception of a singing voice for FM rates between 4.1 and 7.5 Hz and FM excursions between 17 and 83 cents on average. In contrast, HI listeners showed substantially broader vibrato maps. Individual differences in map boundaries were, overall, not correlated with audibility or frequency selectivity at the vowel fundamental frequency, with no clear effect of musical experience. Overall, it was shown that hearing loss affects the perception of a sung vowel based on FM-rate and FM-excursion cues, possibly due to deficits in FM detection or discrimination or to a degraded ability to follow the rate of frequency changes.

  2. Average bit error rate performance analysis of subcarrier intensity modulated MRC and EGC FSO systems with dual branches over M distribution turbulence channels

    NASA Astrophysics Data System (ADS)

    Wang, Ran-ran; Wang, Ping; Cao, Tian; Guo, Li-xin; Yang, Yintang

    2015-07-01

    Based on the space diversity reception, the binary phase-shift keying (BPSK) modulated free space optical (FSO) system over Málaga (M) fading channels is investigated in detail. Under independently and identically distributed and independently and non-identically distributed dual branches, the analytical average bit error rate (ABER) expressions in terms of H-Fox function for maximal ratio combining (MRC) and equal gain combining (EGC) diversity techniques are derived, respectively, by transforming the modified Bessel function of the second kind into the integral form of Meijer G-function. Monte Carlo (MC) simulation is also provided to verify the accuracy of the presented models.

  3. 75 FR 41876 - Disclosure of Adjustable Rate Mortgages (ARMs) Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-19

    ... URBAN DEVELOPMENT Disclosure of Adjustable Rate Mortgages (ARMs) Rates AGENCY: Office of the Chief... mortgage amount. DATES: Comments Due Date: August 18, 2010. ADDRESSES: Interested persons are invited to... lists the following information: Title of Proposal: Disclosure of Adjustable Rate Mortgages (ARMs) Rates...

  4. Heart-Rate and Breath-Rate Monitor

    NASA Technical Reports Server (NTRS)

    Cooper, T. G.

    1983-01-01

    Circuit requiring only four integrated circuits (IC's) measures both heart rate and breath rate. Phase-locked loops lock on heart-rate and respiration-rate input signals. Each loop IC contains two phase comparators. Positive-edge-triggered circuit used in making monitors insensitive to dutycycle variations.

  5. Heart-Rate and Breath-Rate Monitor

    NASA Technical Reports Server (NTRS)

    Cooper, T. G.

    1983-01-01

    Circuit requiring only four integrated circuits (IC's) measures both heart rate and breath rate. Phase-locked loops lock on heart-rate and respiration-rate input signals. Each loop IC contains two phase comparators. Positive-edge-triggered circuit used in making monitors insensitive to dutycycle variations.

  6. 29 CFR 778.112 - Day rates and job rates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Day rates and job rates. 778.112 Section 778.112 Labor... Requirements Principles for Computing Overtime Pay Based on the âregular Rateâ § 778.112 Day rates and job rates. If the employee is paid a flat sum for a day's work or for doing a particular job, without regard...

  7. 29 CFR 778.112 - Day rates and job rates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Day rates and job rates. 778.112 Section 778.112 Labor... Requirements Principles for Computing Overtime Pay Based on the âregular Rateâ § 778.112 Day rates and job rates. If the employee is paid a flat sum for a day's work or for doing a particular job, without regard...

  8. 29 CFR 778.112 - Day rates and job rates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Day rates and job rates. 778.112 Section 778.112 Labor... Requirements Principles for Computing Overtime Pay Based on the âregular Rateâ § 778.112 Day rates and job rates. If the employee is paid a flat sum for a day's work or for doing a particular job, without regard...

  9. 29 CFR 778.112 - Day rates and job rates.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Day rates and job rates. 778.112 Section 778.112 Labor... Requirements Principles for Computing Overtime Pay Based on the âregular Rateâ § 778.112 Day rates and job rates. If the employee is paid a flat sum for a day's work or for doing a particular job, without regard...

  10. 29 CFR 778.112 - Day rates and job rates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Day rates and job rates. 778.112 Section 778.112 Labor... Requirements Principles for Computing Overtime Pay Based on the âregular Rateâ § 778.112 Day rates and job rates. If the employee is paid a flat sum for a day's work or for doing a particular job, without regard...

  11. Minimizing Variation In Outdoor CPV Power Ratings

    NASA Astrophysics Data System (ADS)

    Muller, Matthew; Marion, Bill; Rodriguez, Jose; Kurtz, Sarah

    2011-12-01

    The CPV community has agreed to have both indoor and outdoor module power ratings. The indoor rating provides a repeatable measurement off the factory line while the outdoor rating provides a measure of true on-sun performance. The challenge with an outdoor rating is that conditions that impact the measurement such as the spectrum, temperature, wind speed, etc are constantly in flux. This work examines methodologies for determining the outdoor power rating with the goal of minimizing variation even if data are collected under changing meteorological conditions.

  12. Rates of Earth degassing

    NASA Technical Reports Server (NTRS)

    Onions, R. K.

    1994-01-01

    The degassing of the Earth during accretion is constrained by Pu-U-I-Xe systematics. Degassing was much more efficient during the first 100-200 Ma than subsequently, and it was more complete for Xe than for the lighter gases. More than 90 percent of the degassed Xe escaped from the atmosphere during this period. The combination of fractional degassing of melts and rare gas escape from the atmosphere is able to explain the deficit of terrestrial Xe as a simple consequence of this early degassing history. By the time Xe was quantitatively retained in the atmosphere, the abundances of Kr and the lighter gases in the Earth's interior were similar to or higher than the present-day atmospheric abundances. Subsequent transfer of these lighter rare gases into the atmosphere requires a high rate of post-accretion degassing and melt production. Considerations of Pu-U-Xe systematics suggest that relatively rapid post-accretion degassing was continued to ca. 4.1-4.2 Ga. The present-day degassing history of the Earth is investigated through consideration of rare gas isotope abundances. Although the Earth is a highly degassed body, depleted in rare gases by many orders of magnitude relative to their solar abundances, it is at the present-day losing primordial rare gases which were trapped at the time of accretion.

  13. A Beat Frequency RF Modulator for Generation of Low Repetition Rate Electron Microbunches for the CEBAF Polarized Source

    SciTech Connect

    John Musson; Reza Kazimi; Benard Poelker; Joseph Grames; John Hansknecht

    2007-06-25

    Fiber-based drive lasers now produce all of the spin-polarized electron beams at CEBAF/Jefferson Lab. The flexibility of these drive lasers, combined with the existing three-beam CEBAF photoinjector Chopper, provides a means to implement a beat frequency technique to produce long time intervals between individual electron microbunches (tens of nanoseconds) by merely varying the nominal 499 MHz drive laser frequency by < 20%. This submission describes the RF Laser modulator that uses a divider and heterodyne scheme to maintain coherence with the accelerator Master Oscillator (MO), while providing delay resolution in increments of 2ns. Some possible uses for such a beam are discussed as well as intended future development.

  14. Sequential Effects in Essay Ratings

    ERIC Educational Resources Information Center

    Attali, Yigal

    2011-01-01

    Contrary to previous research on sequential ratings of student performance, this study found that professional essay raters of a large-scale standardized testing program produced ratings that were drawn toward previous ratings, creating an assimilation effect. Longer intervals between the two adjacent ratings and higher degree of agreement with…

  15. Sequential Effects in Essay Ratings

    ERIC Educational Resources Information Center

    Attali, Yigal

    2011-01-01

    Contrary to previous research on sequential ratings of student performance, this study found that professional essay raters of a large-scale standardized testing program produced ratings that were drawn toward previous ratings, creating an assimilation effect. Longer intervals between the two adjacent ratings and higher degree of agreement with…

  16. Performance Ratings and Librarians Rights

    ERIC Educational Resources Information Center

    Peele, David

    1970-01-01

    Two aspects of rating personnel performance are explored: (1) the rating form and some guidelines for filling it in and (2) the right of the librarian who is being rated to discuss or appeal a rating he believes to be biased. (NH)

  17. A NEW PARADIGM FOR GAMMA-RAY BURSTS: LONG-TERM ACCRETION RATE MODULATION BY AN EXTERNAL ACCRETION DISK

    SciTech Connect

    Cannizzo, J. K. E-mail: gehrels@milkyway.gsfc.nasa.gov

    2009-08-01

    We present a new way of looking at the very long-term evolution of gamma-ray bursts (GRBs) in which the disk of material surrounding the putative black hole powering the GRB jet modulates the mass flow, and hence the efficacy of the process that extracts rotational energy from the black hole and inner accretion disk. The pre-Swift paradigm of achromatic, shallow-to-steep 'breaks' in the long-term GRB light curves has not been borne out by detailed Swift data amassed in the past several years. We argue that, given the initial existence of a fall-back disk near the progenitor, an unavoidable consequence will be the formation of an 'external disk' whose outer edge continually moves to larger radii due to angular momentum transport and lack of a confining torque. The mass reservoir at large radii moves outward with time and gives a natural power-law decay to the GRB light curves. In this model, the different canonical power-law decay segments in the GRB identified by Zhang et al. and Nousek et al. represent different physical states of the accretion disk. We identify a physical disk state with each power-law segment.

  18. Dopaminergic Drugs Modulate Learning Rates and Perseveration in Parkinson’s Patients in a Dynamic Foraging Task

    PubMed Central

    Rutledge, Robb B.; Lazzaro, Stephanie C.; Lau, Brian; Myers, Catherine E.; Gluck, Mark A.; Glimcher, Paul W.

    2012-01-01

    Making appropriate choices often requires the ability to learn the value of available options from experience. Parkinson’s disease is characterized by a loss of dopamine neurons in the substantia nigra, neurons hypothesized to play a role in reinforcement learning. Although previous studies have shown that Parkinson’s patients are impaired in tasks involving learning from feedback, they have not directly tested the widely held hypothesis that dopamine neuron activity specifically encodes the reward prediction error signal used in reinforcement learning models. To test a key prediction of this hypothesis, we fit choice behavior from a dynamic foraging task with reinforcement learning models and show that treatment with dopaminergic drugs alters choice behavior in a manner consistent with the theory. More specifically, we found that dopaminergic drugs selectively modulate learning from positive outcomes. We observed no effect of dopaminergic drugs on learning from negative outcomes. We also found a novel dopamine-dependent effect on decision making that is not accounted for by reinforcement learning models: perseveration in choice, independent of reward history, increases with Parkinson’s disease and decreases with dopamine therapy. PMID:19955362

  19. The octopus vertical lobe modulates short-term learning rate and uses LTP to acquire long-term memory.

    PubMed

    Shomrat, Tal; Zarrella, Ilaria; Fiorito, Graziano; Hochner, Binyamin

    2008-03-11

    Analyzing the processes and neuronal circuitry involved in complex behaviors in phylogenetically remote species can help us understand the evolution and function of these systems. Cephalopods, with their vertebrate-like behaviors but much simpler brains, are ideal for such an analysis. The vertical lobe (VL) of Octopus vulgaris is a pivotal brain station in its learning and memory system. To examine the organization of the learning and memory circuitry and to test whether the LTP that we discovered in the VL is involved in behavioral learning, we tetanized the VL to induce a global synaptic enhancement of the VL pathway. The effects of tetanization on learning and memory of a passive avoidance task were compared to those of transecting the same pathway. Tetanization accelerated and transection slowed short-term learning to avoid attacking a negatively reinforced object. However, both treatments impaired long-term recall the next day. Our results suggest that the learning and memory system in the octopus, as in mammals [9], is separated into short- and long-term memory sites. In the octopus, the two memory sites are not independent; the VL, which mediates long-term memory acquisition through LTP, also modulates the circuitry controlling behavior and short-term learning.

  20. A New Paradigm for Gamma Ray Bursts: Long Term Accretion Rate Modulation by an External Accretion Disk

    NASA Technical Reports Server (NTRS)

    Cannizzo, John; Gehrels, Neil

    2009-01-01

    We present a new way of looking at the very long term evolution of GRBs in which the disk of material surrounding the putative black hole powering the GRB jet modulates the mass flow, and hence the efficacy of the process that extracts rotational energy from the black hole and inner accretion disk. The pre-Swift paradigm of achromatic, shallow-to-steep "breaks" in the long term GRB light curves has not been borne out by detailed Swift data amassed in the past several years. We argue that, given the initial existence of a fall-back disk near the progenitor, an unavoidable consequence will be the formation of an "external disk" whose outer edge continually moves to larger radii due to angular momentum transport and lack of a confining torque. The mass reservoir at large radii moves outward with time and gives a natural power law decay to the GRB light curves. In this model, the different canonical power law decay segments in the GRB identified by Zhang et al. and Nousek et al. represent different physical states of the accretion disk. We identify a physical disk state with each power law segment.

  1. The El Niño Southern Oscillation (ENSO) induced modulations in precipitation and nitrogen wet deposition rates in the continental United States

    NASA Astrophysics Data System (ADS)

    Nergui, T.; Chung, S. H.; Adam, J. C.; Evans, R. D.

    2015-12-01

    The ENSO affects atmospheric nitrogen (N) deposition rates through its modulation on N wet deposition. Precipitation and wet deposition measurements at 151 sites of the National Atmospheric Deposition Program/National Trends Network and the NINO3.4 SST climate index from the NOAA's Climate Prediction Center are analyzed to determine the impacts of the ENSO on N wet deposition and precipitation rates in the continental U.S. Precipitation and N wet deposition time series are dominated by high frequency components; however, they contain a wide range of inter-annual frequency components depending on the location. At the 2-to 6-year timescale, variability of precipitation and N wet deposition rates in the Pacific Northwest, the Rocky Mountains, the Gulf States, the Northeast, and the Great Lakes regions are correlated with that of the NINO3.4 index (r2= 0.09-0.59 for precipitation and r2= 0.09-0.52 for N wet deposition, p<0.05). The spatial patterns and strength of the correlations vary by region and season. The correlations are the strongest and most spatially extensive during winter; 46-62% and 46-53% of the 2- to 6-year variability of precipitation and N wet deposition rates in the Rocky Mountains, the Gulf of Mexico, and near the Great Lakes can be explained by ENSO activity. The wintertime relationships tend to hold through springtime in the Great Lakes, the Ohio River Valley, and the Northeast. During the El Niño winters and springs, N wet deposition rates are higher than normal (greater than the 70thpercentile) in the southern Great Plains and the Gulf Coast. Winter and spring La Niña episodes bring precipitation and N wet deposition rates above normal over the Cascades, the Ohio River Valley, the Northeast and the Great Lakes regions. The ensemble mean of eleven coupled General Circulation Models (Yeh et al., 2009) shows that the weak ENSO cycles, having small to moderate amplitudes and reoccurring in shorter time intervals, are projected to dominate in the 21

  2. Use of the dental disease nonbattle injury encounter module to assess the emergency rate on an Army military installation within the United States.

    PubMed

    Colthirst, Paul; DeNicolo, Philip; Will, Randy; Simecek, John W

    2012-09-01

    The objectives of this study are (1) to establish a baseline rate for dental emergencies (DE) occurring within a Brigade Combat Team (BCT) garrisoned on a military installation located in the continental United States (CONUS), and (2) to determine if differences in risk of DE are observed in soldiers of different Dental Fitness Classifications (DFC). Data concerning DE were documented by Army Dental Corps providers using CONUS Dental Disease Nonbattle Injury Emergency Encounter module of the Corporate Dental Application (CDA). The data were collected from September 1, 2011 to December 15, 2011. The number of soldiers at risk, the BCT dental readiness, the DFC of each soldier who experienced a DE, and the date of the dental visit that preceded the DE were documented from CDA. The estimated rate of 221 DE per 1,000 soldiers per year was observed. The risk of DE for DFC 3 soldiers was five times that of soldiers who were DFC 1 or 2. Assessing the DE rate of a BCT in garrison is useful for stakeholders and policymakers who must accommodate the impact of DE on mission readiness.

  3. Proteome-wide muscle protein fractional synthesis rates predict muscle mass gain in response to a selective androgen receptor modulator in rats.

    PubMed

    Shankaran, Mahalakshmi; Shearer, Todd W; Stimpson, Stephen A; Turner, Scott M; King, Chelsea; Wong, Po-Yin Anne; Shen, Ying; Turnbull, Philip S; Kramer, Fritz; Clifton, Lisa; Russell, Alan; Hellerstein, Marc K; Evans, William J

    2016-03-15

    Biomarkers of muscle protein synthesis rate could provide early data demonstrating anabolic efficacy for treating muscle-wasting conditions. Androgenic therapies have been shown to increase muscle mass primarily by increasing the rate of muscle protein synthesis. We hypothesized that the synthesis rate of large numbers of individual muscle proteins could serve as early response biomarkers and potentially treatment-specific signaling for predicting the effect of anabolic treatments on muscle mass. Utilizing selective androgen receptor modulator (SARM) treatment in the ovariectomized (OVX) rat, we applied an unbiased, dynamic proteomics approach to measure the fractional synthesis rates (FSR) of 167-201 individual skeletal muscle proteins in triceps, EDL, and soleus. OVX rats treated with a SARM molecule (GSK212A at 0.1, 0.3, or 1 mg/kg) for 10 or 28 days showed significant, dose-related increases in body weight, lean body mass, and individual triceps but not EDL or soleus weights. Thirty-four out of the 94 proteins measured from the triceps of all rats exhibited a significant, dose-related increase in FSR after 10 days of SARM treatment. For several cytoplasmic proteins, including carbonic anhydrase 3, creatine kinase M-type (CK-M), pyruvate kinase, and aldolase-A, a change in 10-day FSR was strongly correlated (r(2) = 0.90-0.99) to the 28-day change in lean body mass and triceps weight gains, suggesting a noninvasive measurement of SARM effects. In summary, FSR of multiple muscle proteins measured by dynamics of moderate- to high-abundance proteins provides early biomarkers of the anabolic response of skeletal muscle to SARM. Copyright © 2016 the American Physiological Society.

  4. The lateral paragigantocellular nucleus modulates parasympathetic cardiac neurons: a mechanism for rapid eye movement sleep-dependent changes in heart rate.

    PubMed

    Dergacheva, Olga; Wang, Xin; Lovett-Barr, Mary R; Jameson, Heather; Mendelowitz, David

    2010-08-01

    Rapid eye movement (REM) sleep is generally associated with a withdrawal of parasympathetic activity and heart rate increases; however, episodic vagally mediated heart rate decelerations also occur during REM sleep. This alternating pattern of autonomic activation provides a physiological basis for REM sleep-induced cardiac arrhythmias. Medullary neurons within the lateral paragigantocellular nucleus (LPGi) are thought to be active after REM sleep recovery and play a role in REM sleep control. In proximity to the LPGi are parasympathetic cardiac vagal neurons (CVNs) within the nucleus ambiguus (NA), which are critical for controlling heart rate. This study examined brain stem pathways that may mediate REM sleep-related reductions in parasympathetic cardiac activity. Electrical stimulation of the LPGi evoked inhibitory GABAergic postsynaptic currents in CVNs in an in vitro brain stem slice preparation in rats. Because brain stem cholinergic mechanisms are involved in REM sleep regulation, we also studied the role of nicotinic neurotransmission in modulation of GABAergic pathway from the LGPi to CVNs. Application of nicotine diminished the GABAergic responses evoked by electrical stimulation. This inhibitory effect of nicotine was prevented by the alpha7 nicotinic receptor antagonist alpha-bungarotoxin. Moreover, hypoxia/hypercapnia (H/H) diminished LPGi-evoked GABAergic current in CVNs, and this inhibitory effect was also prevented by alpha-bungarotoxin. In conclusion, stimulation of the LPGi evokes an inhibitory pathway to CVNs, which may constitute a mechanism for the reduced parasympathetic cardiac activity and increase in heart rate during REM sleep. Inhibition of this pathway by nicotinic receptor activation and H/H may play a role in REM sleep-related and apnea-associated bradyarrhythmias.

  5. Impact of dose rate on accuracy of intensity modulated radiation therapy plan delivery using the pretreatment portal dosimetry quality assurance and setting up the workflow at hospital levels

    PubMed Central

    Kaviarasu, Karunakaran; Raj, N. Arunai Nambi; Murthy, K. Krishna; Babu, A. Ananda Giri; Prasad, Bhaskar Laxman Durga

    2015-01-01

    The aim of this study was to examine the impact of dose rate on accuracy of intensity modulated radiation therapy (IMRT) plan delivery by comparing the gamma agreement between the calculated and measured portal doses by pretreatment quality assurance (QA) using electronic portal imaging device dosimetry and creating a workflow for the pretreatment IMRT QA at hospital levels. As the improvement in gamma agreement leads to increase in the quality of IMRT treatment delivery, gamma evaluation was carried out for the calculated and the measured portal images for the criteria of 3% dose difference and 3 mm distance-to-agreement (DTA). Three gamma parameters: Maximum gamma, average gamma, and percentage of the field area with a gamma value>1.0 were analyzed. Three gamma index parameters were evaluated for 40 IMRT plans (315 IMRT fields) which were calculated for 400 monitor units (MU)/min dose rate and maximum multileaf collimator (MLC) speed of 2.5 cm/s. Gamma parameters for all 315 fields are within acceptable limits set at our center. Further, to improve the gamma results, we set an action level for this study using the mean and standard deviation (SD) values from the 315 fields studied. Forty out of 315 IMRT fields showed low gamma agreement (gamma parameters>2 SD as per action level of the study). The parameters were recalculated and reanalyzed for the dose rates of 300, 400 and 500 MU/min. Lowering the dose rate helped in getting an enhanced gamma agreement between the calculated and measured portal doses of complicated fields. This may be attributed to the less complex motion of MLC over time and the MU of the field/segment. An IMRT QA work flow was prepared which will help in improving the quality of IMRT delivery. PMID:26865759

  6. Association between heart rate variability and manual pulse rate.

    PubMed

    Hart, John

    2013-09-01

    One model for neurological assessment in chiropractic pertains to autonomic variability, tested commonly with heart rate variability (HRV). Since HRV may not be convenient to use on all patient visits, more user-friendly methods may help fill-in the gaps. Accordingly, this study tests the association between manual pulse rate and heart rate variability. The manual rates were also compared to the heart rate derived from HRV. Forty-eight chiropractic students were examined with heart rate variability (SDNN and mean heart rate) and two manual radial pulse rate measurements. Inclusion criteria consisted of participants being chiropractic students. Exclusion criteria for 46 of the participants consisted of a body mass index being greater than 30, age greater than 35, and history of: a) dizziness upon standing, b) treatment of psychiatric disorders, and c) diabetes. No exclusion criteria were applied to the remaining two participants who were also convenience sample volunteers. Linear associations between the manual pulse rate methods and the two heart rate variability measures (SDNN and mean heart) were tested with Pearson's correlation and simple linear regression. Moderate strength inverse (expected) correlations were observed between both manual pulse rate methods and SDNN (r = -0.640, 95% CI -0.781, -0.435; r = -0.632, 95% CI -0.776, -0.425). Strong direct (expected) relationships were observed between the manual pulse rate methods and heart rate derived from HRV technology (r = 0.934, 95% CI 0.885, 0.962; r = 0.941, 95% CI 0.897, 0.966). Manual pulse rates may be a useful option for assessing autonomic variability. Furthermore, this study showed a strong relationship between manual pulse rates and heart rate derived from HRV technology.

  7. National Utility Rate Database: Preprint

    SciTech Connect

    Ong, S.; McKeel, R.

    2012-08-01

    When modeling solar energy technologies and other distributed energy systems, using high-quality expansive electricity rates is essential. The National Renewable Energy Laboratory (NREL) developed a utility rate platform for entering, storing, updating, and accessing a large collection of utility rates from around the United States. This utility rate platform lives on the Open Energy Information (OpenEI) website, OpenEI.org, allowing the data to be programmatically accessed from a web browser, using an application programming interface (API). The semantic-based utility rate platform currently has record of 1,885 utility rates and covers over 85% of the electricity consumption in the United States.

  8. 2007 Wholesale Power Rate Schedules : 2007 General Rate Schedule Provisions.

    SciTech Connect

    United States. Bonneville Power Administration.

    2006-11-01

    This schedule is available for the contract purchase of Firm Power to be used within the Pacific Northwest (PNW). Priority Firm (PF) Power may be purchased by public bodies, cooperatives, and Federal agencies for resale to ultimate consumers, for direct consumption, and for Construction, Test and Start-Up, and Station Service. Rates in this schedule are in effect beginning October 1, 2006, and apply to purchases under requirements Firm Power sales contracts for a three-year period. The Slice Product is only available for public bodies and cooperatives who have signed Slice contracts for the FY 2002-2011 period. Utilities participating in the Residential Exchange Program (REP) under Section 5(c) of the Northwest Power Act may purchase Priority Firm Power pursuant to the Residential Exchange Program. Rates under contracts that contain charges that escalate based on BPA's Priority Firm Power rates shall be based on the three-year rates listed in this rate schedule in addition to applicable transmission charges. This rate schedule supersedes the PF-02 rate schedule, which went into effect October 1, 2001. Sales under the PF-07 rate schedule are subject to BPA's 2007 General Rate Schedule Provisions (2007 GRSPs). Products available under this rate schedule are defined in the 2007 GRSPs. For sales under this rate schedule, bills shall be rendered and payments due pursuant to BPA's 2007 GRSPs and billing process.

  9. Content and ratings of mature-rated video games.

    PubMed

    Thompson, Kimberly M; Tepichin, Karen; Haninger, Kevin

    2006-04-01

    To quantify the depiction of violence, blood, sexual themes, profanity, substances, and gambling in video games rated M (for "mature") and to measure agreement between the content observed and the rating information provided to consumers on the game box by the Entertainment Software Rating Board. We created a database of M-rated video game titles, selected a random sample, recorded at least 1 hour of game play, quantitatively assessed the content, performed statistical analyses to describe the content, and compared our observations with the Entertainment Software Rating Board content descriptors and results of our prior studies. Harvard University, Boston, Mass. Authors and 1 hired game player. M-rated video games. Percentages of game play depicting violence, blood, sexual themes, gambling, alcohol, tobacco, or other drugs; use of profanity in dialogue, song lyrics, or gestures. Although the Entertainment Software Rating Board content descriptors for violence and blood provide a good indication of such content in the game, we identified 45 observations of content that could warrant a content descriptor in 29 games (81%) that lacked these content descriptors. M-rated video games are significantly more likely to contain blood, profanity, and substances; depict more severe injuries to human and nonhuman characters; and have a higher rate of human deaths than video games rated T (for "teen"). Parents and physicians should recognize that popular M-rated video games contain a wide range of unlabeled content and may expose children and adolescents to messages that may negatively influence their perceptions, attitudes, and behaviors.

  10. Textbook Deficiencies: Ambiguities in Chemical Kinetics Rates and Rate Constants

    NASA Astrophysics Data System (ADS)

    Quisenberry, Keith T.; Tellinghuisen, Joel

    2006-03-01

    Balanced chemical reactions often have at least some stoichiometry coefficients that are not unity. To avoid ambiguity in defining the kinetics rate for a reaction, the IUPAC has established the convention, rate = (1/ν i )/(d[A i ]/d t ) relating the reaction rate to the rate of change of concentration of any reactant or product A i and its stoichiometry number ν i (negative for reactants, positive for products). The rate is a product of the rate constant k and some function of the concentrations of reactants and products that must be determined experimentally. While most general chemistry textbooks correctly state this convention, most also proceed to ignore it in subsequent development, particularly in the use of integrated rate laws and the definition of the reaction half-life. We recommend that in future editions, authors make it clear that (i) the reaction rate and rate constant cannot be defined unambiguously without explicitly stating the reaction for which they apply and therefore (ii) the relation between the half-life, which is a physical property of the reaction system, and the rate constant depends upon how the reaction is written. The errors have arisen in part because most texts simply state the integrated rate expressions for first- and second-order reactions without deriving them. It is both appropriate and easy to include such derivations in texts oriented toward students intending careers in science, engineering, and medicine.

  11. Breast Cancer Rates by State

    MedlinePlus

    ... Associated Lung Ovarian Prostate Skin Uterine Cancer Home Breast Cancer Rates by State Language: English Español (Spanish) Recommend ... from breast cancer each year. Rates of Getting Breast Cancer by State The number of people who get ...

  12. Survival Rates for Thymus Cancer

    MedlinePlus

    ... Early Detection, Diagnosis, and Staging Survival Rates for Thymus Cancer Survival rates are often used by doctors ... Ask Your Doctor About Thymus Cancer? More In Thymus Cancer About Thymus Cancer Causes, Risk Factors, and ...

  13. All about Heart Rate (Pulse)

    MedlinePlus

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More All About Heart Rate (Pulse) Updated:Apr 19,2016 ... are the Symptoms of High Blood Pressure? 7 All About Heart Rate (Pulse) 8 Tachycardia | Fast Heart ...

  14. Lung Cancer Rates by State

    MedlinePlus

    ... HPV-Associated Ovarian Prostate Skin Uterine Cancer Home Lung Cancer Rates by State Language: English Español (Spanish) ... incidence data are currently available. Rates of Getting Lung Cancer by State The number of people who ...

  15. The use of heart rate variability measures as indicators of autonomic nervous modulation must be careful in patients after orthotopic heart transplantation.

    PubMed

    Lu, Wan-An; Chen, Gau-Yang; Shih, Chun-Che; Kuo, Cheng-Deng

    2016-10-01

    The precise relation between heart rate variability (HRV) and autonomic re-innervation has not been established explicitly in patients after orthotopic heart transplantation (OHT), but can be inferred from the fact that the HRV is reduced immediately after OHT and may increase gradually with time. The aim of this study was to investigate the residual HRV in patients about 1-2 years after OHT, as compared with patients after coronary artery bypass graft (CABG) surgery. Thirteen patients who had received OHT and 14 patients who had received CABG surgery were recruited. HRV analysis was performed and the HRV measures in supine position were compared between these two groups of patients. We found that the mean (mRRI), standard deviation and coefficient of variation of RR intervals, total power, very low frequency power (VLFP), low frequency power, high frequency power (HFP), normalized VLFP (nVLFP) and low-/high-frequency power ratio in the OHT group were all significantly decreased, while the heart rate (HR) and normalized HFP (nHFP) were significantly increased, as compared with the CABG group. The decrease in HRV was more severe in the VLFP region. A smaller nVLFP and a greater nHFP were associated with a smaller mRRI and a larger HR in the OHT patients. The slope of the power law relation of HRV became positive in OHT patients, instead of negative in CABG patients. We conclude that patients after OHT have residual HRV which were characterized by severely depressed time and frequency domain HRV, increased HR and nHFP, decreased nVLFP, and positive slope of the power-law relation of HRV. The use of nHFP as the indicator of vagal modulation and the use of nVLFP as the indicator of renin-angiotensin modulation, thermoregulation and vagal withdrawal must be careful in the OHT patients.

  16. Minimizing Variation in Outdoor CPV Power Ratings (Presentation)

    SciTech Connect

    Muller, M.

    2011-02-01

    Module data from NREL's CPV test bed is used to examine methods for calculating outdoor CPV power ratings. IEC 62670 and ASTM E2527 are used as a starting point for determining a module power rating on a monthly basis. Monthly power ratings vary by more than desired using existing methods. The presentation examines modifications to existing methods as well as spectral corrections to reduce variation in monthly module power ratings.

  17. MEMS Rate Sensors for Space

    NASA Technical Reports Server (NTRS)

    Gambino, Joel P.

    1999-01-01

    Micromachined Electro Mechanical System Rate sensors offer many advantages that make them attractive for space use. They are smaller, consume less power, and cost less than the systems currently available. MEMS Rate Sensors however, have not been optimized for use on spacecraft. This paper describes an approach to developing MEMS Rate Sensors systems for space use.

  18. Rate and Occupancy Survey Results.

    ERIC Educational Resources Information Center

    Mid-Atlantic Association of Coll. and Univ. Housing Officers.

    In its annual effort to determine rate and occupancy trends in the Mid-Atlantic region, MACUHO surveyed by questionnaire the chief housing officers on its mailing list and received 99 usable responses, compared with 65 the previous year. The average double room rate was reported to be $691, compared with $646 in 1975; the average board rate rose…

  19. Nodal Clearance Rate and Long-Term Efficacy of Individualized Sentinel Node-Based Pelvic Intensity Modulated Radiation Therapy for High-Risk Prostate Cancer.

    PubMed

    Müller, Arndt-Christian; Eckert, Franziska; Paulsen, Frank; Zips, Daniel; Stenzl, Arnulf; Schilling, David; Alber, Markus; Bares, Roland; Martus, Peter; Weckermann, Dorothea; Belka, Claus; Ganswindt, Ute

    2016-02-01

    To assess the efficacy of individual sentinel node (SN)-guided pelvic intensity modulated radiation therapy (IMRT) by determining nodal clearance rate [(n expected nodal involvement - n observed regional recurrences)/n expected nodal involvement] in comparison with surgically staged patients. Data on 475 high-risk prostate cancer patients were examined. Sixty-one consecutive patients received pelvic SN-based IMRT (5 × 1.8 Gy/wk to 50.4 Gy [pelvic nodes + individual SN] and an integrated boost with 5 × 2.0 Gy/wk to 70.0 Gy to prostate + [base of] seminal vesicles) and neo-/adjuvant long-term androgen deprivation therapy; 414 patients after SN-pelvic lymph node dissection were used to calculate the expected nodal involvement rate for the radiation therapy sample. Biochemical control and overall survival were estimated for the SN-IMRT patients using the Kaplan-Meier method. The expected frequency of nodal involvement in the radiation therapy group was estimated by imputing frequencies of node-positive patients in the surgical sample to the pattern of Gleason, prostate-specific antigen, and T category in the radiation therapy sample. After a median follow-up of 61 months, 5-year OS after SN-guided IMRT reached 84.4%. Biochemical control according to the Phoenix definition was 73.8%. The nodal clearance rate of SN-IMRT reached 94%. Retrospective follow-up evaluation is the main limitation. Radiation treatment of pelvic nodes individualized by inclusion of SNs is an effective regional treatment modality in high-risk prostate cancer patients. The pattern of relapse indicates that the SN-based target volume concept correctly covers individual pelvic nodes. Thus, this SN-based approach justifies further evaluation, including current dose-escalation strategies to the prostate in a larger prospective series. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Aberrant Meiotic Modulation Partially Contributes to the Lower Germination Rate of Pollen Grains in Maize (Zea mays L.) Under Low Nitrogen Supply.

    PubMed

    Zheng, Hongyan; Wu, Huamao; Pan, Xiaoying; Jin, Weiwei; Li, Xuexian

    2016-11-15

    Pollen germination is an essential step towards successful pollination during maize reproduction. How low niutrogen (N) affects pollen germination remains an interesting biological question to be addressed. We found that only low N resulted in a significantly lower germination rate of pollen grains after 4 weeks of low N, phosphorus or potassium treatment in maize production. Importantly, cytological analysis showed 7-fold more micronuclei in male meiocytes under the low N treatment than in the control, indicating that the lower germination rate of pollen grains was partially due to numerous chromosome loss events resulting from preceding meiosis. The appearance of 10 bivalents in the control and low N cells at diakinesis suggested that chromosome pairing and recombination in meiosis I was not affected by low N. Further gene expression analysis revealed dramatic down-regulation of Nuclear Division Cycle 80 (Ndc80) and Regulator of Chromosome Condensation 1 (Rcc1-1) expression and up-regulation of Cell Division Cycle 20 (Cdc20-1) expression, although no significant difference in the expression level of kinetochore foundation proteins Centromeric Histone H3 (Cenh3) and Centromere Protein C (Cenpc) and cohesion regulators Recombination 8 (Rec8) and Shugoshin (Sgo1) was observed. Aberrant modulation of three key meiotic regulators presumably resulted in a high likelihood of erroneous chromosome segregation, as testified by pronounced lagging chromosomes at anaphase I or cell cycle disruption at meiosis II. Thus, we proposed a cytogenetic mechanism whereby low N affects male meiosis and causes a higher chromosome loss frequency and eventually a lower germination rate of pollen grains in a staple crop plant.

  1. Assessment of training effects on autonomic modulation of the cardiovascular system in mature rats using power spectral analysis of heart rate variability.

    PubMed

    Kumae, Takashi

    2012-09-01

    To clarify the effects of forced or voluntary exercise on autonomic modulation of the cardiovascular system, we monitored changes in autonomic nervous activity in a mature rat by spectral analysis of the heart rate (HR) during a 10-week training period. Male Wistar rats implanted with a radio-telemetry system were divided into three groups at 18 weeks of age: (1) Control group (n = 8); (2) Voluntary group (n = 6), which were housed separately in a cage with a running wheel; (3) Forced group (n = 6), which were exercised on a treadmill (35 m/min, 15 min/day, 5 days/week). The electrocardiogram was analyzed by the maximum entropy method into two main oscillations, low-frequency (LF) and high-frequency (HF) oscillations, respectively. LF and HF are considered to be markers of both sympathetic and parasympathetic modulations and parasympathetic modulation, respectively. Average running distances of the Voluntary group were more than twofold higher than those of the Forced group. HR levels in the Forced group were lower than those in the Control group. LF and HF levels in the Control and the Forced groups were almost the same during the experiment, and those in the Voluntary group showed a tendency to decrease. The results in the Voluntary and the Forced groups suggest that cardiovascular adjustments are not simply caused by the quantity of exercise. In the Voluntary group, both sympathetic and parasympathetic activity may decrease with a predominance of sympathetic activity. Conversely, in the Forced group, the baroreflex may be hyper-activated by the undesired treadmill running and handling stress.

  2. Heart rate variability shows different cardiovascular modulation in Parkinson's disease patients with tremor dominant subtype compared to those with akinetic rigid dominant subtype.

    PubMed

    Solla, Paolo; Cadeddu, Christian; Cannas, Antonino; Deidda, Martino; Mura, Nicola; Mercuro, Giuseppe; Marrosu, Francesco

    2015-10-01

    Parkinson's disease (PD) can present with different motor subtypes depending on the predominant symptoms (tremor or rigidity/bradykinesia). Slower disease progression and less cognitive decline are observed in tremor-dominant patients compared to those with akinetic-rigid subtype. Autonomic cardiovascular disorders have been described in parkinsonian patients, although the definite correlations with different subtypes of PD are not clear. In this context, heart rate variability (HRV) analysis represents a non-invasive and established tool in assessing cardiovascular autonomic modulation. We investigate cardiovascular autonomic modulation in PD patients with tremor dominant subtype in comparison to akinetic rigid dominant subtype subjects using HRV analysis. Twenty-eight PD patients (17 with tremor dominant subtype and 11 with akinetic rigid dominant subtype) were enrolled and compared to 17 age and sex-matched healthy controls. HRV was analyzed in time- and frequency-domains. Low-frequency (LF) values were significantly lower in the akinetic rigid dominant subtype than in the tremor dominant group [LF 41.4 ± 13.6 vs 55.5 ± 11.6 (p < 0.007)] indicating that the disease led to a more evident impairment of the baroreflex modulation of the autonomic outflow mediated by both sympathetic and parasympathetic systems in the first class of patients. These findings support the biological relevance of clinical subtypes supporting the idea of a different pathophysiological process between these subtypes. These differences also suggest that different subtypes may also result in different responses to therapy or in the possible development of cardiovascular side effects of dopaminergic drugs in these different populations.

  3. Heart rate monitoring mobile applications

    PubMed Central

    2016-01-01

    Total number of times a heart beats in a minute is known as the heart rate. Traditionally, heart rate was measured using clunky gadgets but these days it can be measured with a smartphone’s camera. This can help you measure your heart rate anywhere and at anytime, especially during workouts so you can adjust your workout intensity to achieve maximum health benefits. With simple and easy to use mobile app, ‘Unique Heart Rate Monitor’, you can also maintain your heart rate history for personal reflection and sharing with a provider. PMID:28293594

  4. Discharge ratings at gaging stations

    USGS Publications Warehouse

    Kennedy, E.J.

    1984-01-01

    A discharge rating is the relation of the discharge at a gaging station to stage and sometimes also to other variables. This chapter of 'Techniques of Water-Resources Investigations' describes the procedures commonly used to develop simple ratings where discharge is related only to stage and the most frequently encountered types of complex ratings where additional factors such as rate of change in stage, water-surface slope, or index velocity are used. Fundamental techniques of logarithmic plotting and the applications of simple storage routing to rating development are demonstrated. Computer applications, especially for handheld programmable calculators, and data handling are stressed.

  5. The Galactic Nova Rate Revisited

    NASA Astrophysics Data System (ADS)

    Shafter, A. W.

    2017-01-01

    Despite its fundamental importance, a reliable estimate of the Galactic nova rate has remained elusive. Here, the overall Galactic nova rate is estimated by extrapolating the observed rate for novae reaching m≤slant 2 to include the entire Galaxy using a two component disk plus bulge model for the distribution of stars in the Milky Way. The present analysis improves on previous work by considering important corrections for incompleteness in the observed rate of bright novae and by employing a Monte Carlo analysis to better estimate the uncertainty in the derived nova rates. Several models are considered to account for differences in the assumed properties of bulge and disk nova populations and in the absolute magnitude distribution. The simplest models, which assume uniform properties between bulge and disk novae, predict Galactic nova rates of ∼50 to in excess of 100 per year, depending on the assumed incompleteness at bright magnitudes. Models where the disk novae are assumed to be more luminous than bulge novae are explored, and predict nova rates up to 30% lower, in the range of ∼35 to ∼75 per year. An average of the most plausible models yields a rate of {50}-23+31 yr‑1, which is arguably the best estimate currently available for the nova rate in the Galaxy. Virtually all models produce rates that represent significant increases over recent estimates, and bring the Galactic nova rate into better agreement with that expected based on comparison with the latest results from extragalactic surveys.

  6. Relaxed Poisson cure rate models.

    PubMed

    Rodrigues, Josemar; Cordeiro, Gauss M; Cancho, Vicente G; Balakrishnan, N

    2016-03-01

    The purpose of this article is to make the standard promotion cure rate model (Yakovlev and Tsodikov, ) more flexible by assuming that the number of lesions or altered cells after a treatment follows a fractional Poisson distribution (Laskin, ). It is proved that the well-known Mittag-Leffler relaxation function (Berberan-Santos, ) is a simple way to obtain a new cure rate model that is a compromise between the promotion and geometric cure rate models allowing for superdispersion. So, the relaxed cure rate model developed here can be considered as a natural and less restrictive extension of the popular Poisson cure rate model at the cost of an additional parameter, but a competitor to negative-binomial cure rate models (Rodrigues et al., ). Some mathematical properties of a proper relaxed Poisson density are explored. A simulation study and an illustration of the proposed cure rate model from the Bayesian point of view are finally presented.

  7. Associations of resting heart rate with endothelium-dependent vasodilation and shear rate.

    PubMed

    Laosiripisan, Jitanan; Parkhurst, Kristin L; Tanaka, Hirofumi

    2017-01-01

    Heart rate is an independent risk factor for cardiovascular disease and a hemodynamic factor that can modulate blood flow as it affects the frequency of shear stimuli acting on the arterial wall. However, the association between heart rate and endothelium-dependent vasodilation remains highly controversial. We determined the association between heart rate at rest and endothelium-dependent vasodilation in 98 apparently healthy adults (18-63 years). The mild and positive association between heart rate and flow-mediated dilation (FMD) was no longer significant when age and sex or baseline diameter were controlled for. The path analyses revealed that heart rate was not directly related to FMD but the association was indirectly mediated by shear rate, which was confirmed by a bias-corrected bootstrap 95% CIs (0.0157-0.1056). We concluded that even though heart rate and endothelium-dependent vasodilation were associated with shear rate, there was no independent relation between heart rate and FMD.

  8. Dose rate mapping of VMAT treatments

    NASA Astrophysics Data System (ADS)

    Podesta, Mark; Antoniu Popescu, I.; Verhaegen, Frank

    2016-06-01

    Human tissues exhibit a varying response to radiation dose depending on the dose rate and fractionation scheme used. Dose rate effects have been reported for different radiations, and tissue types. The literature indicates that there is not a significant difference in response for low-LET radiation when using dose rates between 1 Gy min-1 and 12 Gy min-1 but lower dose rates have an observable sparing effect on tissues and a differential effect between tissues. In intensity-modulated radiotherapy such as volumetric modulated arc therapy (VMAT) the dose can be delivered with a wide range of dose rates. In this work we developed a method based on time-resolved Monte Carlo simulations to quantify the dose rate frequency distribution for clinical VMAT treatments for three cancer sites, head and neck, lung, and pelvis within both planning target volumes (PTV) and normal tissues. The results show a wide range of dose rates are used to deliver dose in VMAT and up to 75% of the PTV can have its dose delivered with dose rates  <1 Gy min-1. Pelvic plans on average have a lower mean dose rate within the PTV than lung or head and neck plans but a comparable mean dose rate within the organs at risk. Two VMAT plans that fulfil the same dose objectives and constraints may be delivered with different dose rate distributions, particularly when comparing single arcs to multiple arc plans. It is concluded that for dynamic plans, the dose rate range used varies to a larger degree than previously assumed. The effect of the dose rate range in VMAT on clinical outcome is unknown.

  9. Dose rate mapping of VMAT treatments.

    PubMed

    Podesta, Mark; Popescu, I Antoniu; Verhaegen, Frank

    2016-06-07

    Human tissues exhibit a varying response to radiation dose depending on the dose rate and fractionation scheme used. Dose rate effects have been reported for different radiations, and tissue types. The literature indicates that there is not a significant difference in response for low-LET radiation when using dose rates between 1 Gy min(-1) and 12 Gy min(-1) but lower dose rates have an observable sparing effect on tissues and a differential effect between tissues. In intensity-modulated radiotherapy such as volumetric modulated arc therapy (VMAT) the dose can be delivered with a wide range of dose rates. In this work we developed a method based on time-resolved Monte Carlo simulations to quantify the dose rate frequency distribution for clinical VMAT treatments for three cancer sites, head and neck, lung, and pelvis within both planning target volumes (PTV) and normal tissues. The results show a wide range of dose rates are used to deliver dose in VMAT and up to 75% of the PTV can have its dose delivered with dose rates  <1 Gy min(-1). Pelvic plans on average have a lower mean dose rate within the PTV than lung or head and neck plans but a comparable mean dose rate within the organs at risk. Two VMAT plans that fulfil the same dose objectives and constraints may be delivered with different dose rate distributions, particularly when comparing single arcs to multiple arc plans. It is concluded that for dynamic plans, the dose rate range used varies to a larger degree than previously assumed. The effect of the dose rate range in VMAT on clinical outcome is unknown.

  10. Uncertainty Analysis for Photovoltaic Degradation Rates (Poster)

    SciTech Connect

    Jordan, D.; Kurtz, S.; Hansen, C.

    2014-04-01

    Dependable and predictable energy production is the key to the long-term success of the PV industry. PV systems show over the lifetime of their exposure a gradual decline that depends on many different factors such as module technology, module type, mounting configuration, climate etc. When degradation rates are determined from continuous data the statistical uncertainty is easily calculated from the regression coefficients. However, total uncertainty that includes measurement uncertainty and instrumentation drift is far more difficult to determine. A Monte Carlo simulation approach was chosen to investigate a comprehensive uncertainty analysis. The most important effect for degradation rates is to avoid instrumentation that changes over time in the field. For instance, a drifting irradiance sensor, which can be achieved through regular calibration, can lead to a substantially erroneous degradation rates. However, the accuracy of the irradiance sensor has negligible impact on degradation rate uncertainty emphasizing that precision (relative accuracy) is more important than absolute accuracy.

  11. Female Literacy Rate is a Better Predictor of Birth Rate and Infant Mortality Rate in India.

    PubMed

    Saurabh, Suman; Sarkar, Sonali; Pandey, Dhruv K

    2013-01-01

    Educated women are known to take informed reproductive and healthcare decisions. These result in population stabilization and better infant care reflected by lower birth rates and infant mortality rates (IMRs), respectively. Our objective was to study the relationship of male and female literacy rates with crude birth rates (CBRs) and IMRs of the states and union territories (UTs) of India. The data were analyzed using linear regression. CBR and IMR were taken as the dependent variables; while the overall literacy rates, male, and female literacy rates were the independent variables. CBRs were inversely related to literacy rates (slope parameter = -0.402, P < 0.001). On multiple linear regression with male and female literacy rates, a significant inverse relationship emerged between female literacy rate and CBR (slope = -0.363, P < 0.001), while male literacy rate was not significantly related to CBR (P = 0.674). IMR of the states were also inversely related to their literacy rates (slope = -1.254, P < 0.001). Multiple linear regression revealed a significant inverse relationship between IMR and female literacy (slope = -0.816, P = 0.031), whereas male literacy rate was not significantly related (P = 0.630). Female literacy is relatively highly important for both population stabilization and better infant health.

  12. Saturn component failure rate and failure rate modifiers

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Failure mode frequency ratios, environmental adjustment factors, and failure rates for mechanical and electromechanical component families are presented. The failure rates and failure rate modifiers resulted from a series of studies whose purpose was to provide design, tests, reliability, and systems engineers with accurate, up-to-date failure rate information. The results of the studies were achieved through an extensive engineering analysis of the Saturn Program test data and Unsatisfactory Condition Reports (UCR's) and the application of mathematical techniques developed for the studies.

  13. Calibration and Rating of Photovoltaics: Preprint

    SciTech Connect

    Emery, K.

    2012-06-01

    Rating the performance of photovoltaic (PV) modules is critical to determining the cost per watt, and efficiency is useful to assess the relative progress among PV concepts. Procedures for determining the efficiency for PV technologies from 1-sun to low concentration to high concentration are discussed. We also discuss the state of the art in primary and secondary calibration of PV reference cells used by calibration laboratories around the world. Finally, we consider challenges to rating PV technologies and areas for improvement.

  14. High data rate systems for the future

    NASA Technical Reports Server (NTRS)

    Chitwood, John

    1991-01-01

    Information systems in the next century will transfer data at rates that are much greater than those in use today. Satellite based communication systems will play an important role in networking users. Typical data rates; use of microwave, millimeter wave, or optical systems; millimeter wave communication technology; modulators/exciters; solid state power amplifiers; beam waveguide transmission systems; low noise receiver technology; optical communication technology; and the potential commercial applications of these technologies are discussed.

  15. Field measurement of ventilation rates.

    PubMed

    Persily, A K

    2016-02-01

    Ventilation rates have significant impacts on building energy use and indoor contaminant concentrations, making them key parameters in building performance. Ventilation rates have been measured in buildings for many decades, and there are mature measurement approaches available to researchers and others who need to know actual ventilation rates in buildings. Despite the fact that ventilation rates are critical in interpreting indoor concentration measurements, it is disconcerting how few Indoor Air Quality field studies measure ventilation rates or otherwise characterize the ventilation design of the study building(s). This paper summarizes parameters of interest in characterizing building ventilation, available methods for quantifying these parameters, and challenges in applying these methods to different types of buildings and ventilation systems. These parameters include whole-building air change rates, system outdoor air intake rates, and building infiltration rates. Tracer gas methods are reviewed as well as system airflow rate measurements using, for example, duct traverses. Several field studies of ventilation rates conducted over the past 75 years are described to highlight the approaches employed and the findings obtained.

  16. Optimizing rating scale category effectiveness.

    PubMed

    Linacre, John M

    2002-01-01

    Rating scales are employed as a means of extracting more information out of an item than would be obtained from a mere "yes/no", "right/wrong" or other dichotomy. But does this additional information increase measurement accuracy and precision? Eight guidelines are suggested to aid the analyst in optimizing the manner in which rating scales categories cooperate in order to improve the utility of the resultant measures. Though these guidelines are presented within the context of Rasch analysis, they reflect aspects of rating scale functioning which impact all methods of analysis. The guidelines feature rating-scale-based data such as category frequency, ordering, rating-to-measure inferential coherence, and the quality of the scale from measurement and statistical perspectives. The manner in which the guidelines prompt recategorization or reconceptualization of the rating scale is indicated. Utilization of the guidelines is illustrated through their application to two published data sets.

  17. Conducting Market Rate Surveys and Establishing Rate Policies.

    ERIC Educational Resources Information Center

    Karolak, Eric; Collins, Ray; Stoney, Louise

    Market rate surveys and the rate-setting policies and reimbursement rules informed by them are at the core of the market-based approach to child care and are central to the delicate balancing act of ensuring access to subsidized care while at the same time promoting the quality of child care. This report provides an overview of the market-based…

  18. Rate My Stake: Interpretation of Ordinal Stake Ratings

    Treesearch

    Patricia Lebow; Grant Kirker

    2014-01-01

    Ordinal rating systems are commonly employed to evaluate biodeterioration of wood exposed outdoors over long periods of time. The purpose of these ratings is to compare the durability of test systems to nondurable wood products or known durable wood products. There are many reasons why these systems have evolved as the chosen method of evaluation, including having an...

  19. 15 CFR 700.3 - Priority ratings and rated orders.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 2 2012-01-01 2012-01-01 false Priority ratings and rated orders. 700.3 Section 700.3 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE NATIONAL SECURITY INDUSTRIAL BASE...

  20. 15 CFR 700.3 - Priority ratings and rated orders.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 2 2014-01-01 2014-01-01 false Priority ratings and rated orders. 700.3 Section 700.3 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE NATIONAL SECURITY INDUSTRIAL BASE...

  1. 15 CFR 700.3 - Priority ratings and rated orders.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 2 2013-01-01 2013-01-01 false Priority ratings and rated orders. 700.3 Section 700.3 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE NATIONAL SECURITY INDUSTRIAL BASE...

  2. 15 CFR 700.3 - Priority ratings and rated orders.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 2 2011-01-01 2011-01-01 false Priority ratings and rated orders. 700.3 Section 700.3 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE NATIONAL SECURITY INDUSTRIAL BASE...

  3. What Are We Rating When We Rate Holistically?

    ERIC Educational Resources Information Center

    Patkowski, Mark S.

    A study of the holistic evaluation of writing compared holistic rating and the rating for "conformity to correct prose" technique, a technique based on error counting, of five essays representing five ability levels. The essays were produced in a college English-as-a-Second-Language program. The two scoring methods produced the same ranking of…

  4. Multi-calculation rate simulations

    NASA Technical Reports Server (NTRS)

    Powell, J. D.; Akhter, M.

    1977-01-01

    It is common in real time simulations of large aerospace systems to separate the high and low frequency subsystems within the simulation and perform the integrations of the subsystems at different calculation rates. This is done to strike a balance between accuracy of calculation and capacity of the digital computer. Questions arising as to the accuracy of this structure compared to single calculation rates were studied using a linear aircraft model. Also investigated were interactions arising to cause errors worse than those expected. Problems are specifically identified and guidelines are given for selection of sample rates for multiple rate simulations.

  5. Mortality rates decline in Malaysia.

    PubMed

    1991-11-01

    Experiencing remarkable decreases in mortality rates over the past 3 decades, Malaysia currently has one of the lowest mortality rates among developing countries, a rate that compares favorably with those of developed countries. Between 1957 and 1989, the crude death rate dropped from 12.4/1000 population to 4.6. Over the same period, Malaysia recorded even greater decreases in the infant mortality rate, from 75.5/1000 births to 15.2. The Maternal mortality rate also declined from 1.48 in 1970 to 0.24 in 1988. The data indicates that mortality rates vary from state to state, and that rural areas have a higher mortality than urban areas. According to a study by the National Population and Family Development Board, the use of maternal and child health services has played an important role in reducing neonatal, perinatal, infant, child, and maternal mortality rates. Nearly all women in Malaysia receive antenatal services. While the country has achieved great gains on mortality rates, programs focusing on specific age and socioeconomic groups could lead to even greater reductions. The Minister for National Unity and Social Development, Dato Napsiah Omar, has called for the development of programs designed to improve the population's quality of life.

  6. A small-signal approach to temporal modulation transfer functions with exposure-rate dependence and its application to fluoroscopic detective quantum efficiency.

    PubMed

    Friedman, S N; Cunningham, I A

    2009-08-01

    The detective quantum efficiency (DQE) is a metric widely used in radiography to quantify system performance and as a surrogate measure of patient "dose efficiency." It has been applied previously to fluoroscopic systems with the introduction of a temporal correction factor. Calculation of this correction factor relies on measurements of the temporal modulation transfer function (MTF). However, the temporal MTF is often exposure-rate dependent, violating a necessary Fourier linearity requirement. The authors show that a Fourier analysis is appropriate for fluoroscopic systems if a "small-signal" approach is used. Using a semitransparent edge, a lag-corrected DQE is described and measured for an x-ray image intensifier-based fluoroscopic system under continuous (non-pulsed) exposure conditions. It was found that results were equivalent for both rising and falling-edge profiles independent of edge attenuation when effective attenuation was in the range of 0.1-0.6. This suggests that this range is appropriate for measuring the small-signal temporal MTF. In general, lag was greatest at low exposure rates. It was also found that results obtained using a falling-edge profile with a radiopaque edge were equivalent to the small-signal results for the test system. If this result is found to be true generally, it removes the need for the small-signal approach. Lag-corrected DQE values were validated by comparison with radiographic DQE values obtained using very long exposures under the same conditions. Lag was observed to inflate DQE measurements by up to 50% when ignored.

  7. A family 11 carbohydrate-binding module (CBM) improves the efficacy of a recombinant cellulase used to supplement barley-based diets for broilers at lower dosage rates.

    PubMed

    Ribeiro, T; Ponte, P I P; Guerreiro, C I P D; Santos, H M; Falcão, L; Freire, J P B; Ferreira, L M A; Prates, J A M; Fontes, C M G A; Lordelo, M M

    2008-09-01

    1. Exogenous microbial beta-1,3-1,4-glucanases and hemicellulases contribute to improving the nutritive value of cereals rich in soluble non-starch polysaccharides for poultry. 2. In general, plant cell wall hydrolases display a modular structure comprising a catalytic module linked to one or more non-catalytic carbohydrate-binding modules (CBMs). Based on primary structure similarity, CBMs have been classified in 50 different families. CBMs anchor cellulases and hemicellulases into their target substrates, therefore eliciting efficient hydrolysis of recalcitrant polysaccharides. 3. A study was undertaken to investigate the effects of a family 11 beta-glucan-binding domain in the function of recombinant derivatives of cellulase CtLic26A-Cel5E of Clostridium thermocellum that were used to supplement a barley-based diet at lower dosage rates. 4. The results showed that birds fed on diets supplemented with the recombinant CtLic26A-Cel5E modular derivative containing the family 11 CBM or the commercial enzyme mixture Rovabio Excel AP tended to display improved performance when compared to birds fed diets not supplemented with exogenous enzymes. 5. It is suggested that at lower than previously reported enzyme dosage (10 U/kg vs 30 U/kg of basal diet), the beta-glucan-binding domain also elicits the function of the recombinant CtLic26A-Cel5E derivatives. 6. Finally, the data suggest that exogenous enzymes added to barley-based diets act primarily in the proximal section of the gastrointestinal tract.

  8. H2O2 production rate in Lactobacillus johnsonii is modulated via the interplay of a heterodimeric flavin oxidoreductase with a soluble 28 Kd PAS domain containing protein

    PubMed Central

    Valladares, Ricardo B.; Graves, Christina; Wright, Kaitlyn; Gardner, Christopher L.; Lorca, Graciela L.; Gonzalez, Claudio F.

    2015-01-01

    Host and commensals crosstalk, mediated by reactive oxygen species (ROS), has triggered a growing scientific interest to understand the mechanisms governing such interaction. However, the majority of the scientific studies published do not evaluate the ROS production by commensals bacteria. In this context we recently showed that Lactobacillus johnsonii N6.2, a strain of probiotic value, modulates the activity of the critical enzymes 2,3-indoleamine dioxygenase via H2O2 production. L. johnsonii N6.2 by decreasing IDO activity, is able to modify the tryptophan/kynurenine ratio in the host blood with further systemic consequences. Understanding the mechanisms of H2O2 production is critical to predict the probiotic value of these strains and to optimize bacterial biomass production in industrial processes. We performed a transcriptome analysis to identify genes differentially expressed in L. johnsonii N6.2 cells collected from cultures grown under different aeration conditions. Herein we described the biochemical characteristics of a heterodimeric FMN reductase (FRedA/B) whose in vitro activity is controlled by LjPAS protein with a typical Per-Arnst-Sim (PAS) sensor domain. Interestingly, LjPAS is fused to the FMN reductase domains in other lactobacillaceae. In L. johnsonii, LjPAS is encoded by an independent gene which expression is repressed under anaerobic conditions (>3 fold). Purified LjPAS was able to slow down the FRedA/B initial activity rate when the holoenzyme precursors (FredA, FredB, and FMN) were mixed in vitro. Altogether the results obtained suggest that LjPAS module regulates the H2O2 production helping the cells to minimize oxidative stress in response to environmental conditions. PMID:26236298

  9. Assessing dose rate distributions in VMAT plans

    NASA Astrophysics Data System (ADS)

    Mackeprang, P.-H.; Volken, W.; Terribilini, D.; Frauchiger, D.; Zaugg, K.; Aebersold, D. M.; Fix, M. K.; Manser, P.

    2016-04-01

    Dose rate is an essential factor in radiobiology. As modern radiotherapy delivery techniques such as volumetric modulated arc therapy (VMAT) introduce dynamic modulation of the dose rate, it is important to assess the changes in dose rate. Both the rate of monitor units per minute (MU rate) and collimation are varied over the course of a fraction, leading to different dose rates in every voxel of the calculation volume at any point in time during dose delivery. Given the radiotherapy plan and machine specific limitations, a VMAT treatment plan can be split into arc sectors between Digital Imaging and Communications in Medicine control points (CPs) of constant and known MU rate. By calculating dose distributions in each of these arc sectors independently and multiplying them with the MU rate, the dose rate in every single voxel at every time point during the fraction can be calculated. Independently calculated and then summed dose distributions per arc sector were compared to the whole arc dose calculation for validation. Dose measurements and video analysis were performed to validate the calculated datasets. A clinical head and neck, cranial and liver case were analyzed using the tool developed. Measurement validation of synthetic test cases showed linac agreement to precalculated arc sector times within  ±0.4 s and doses  ±0.1 MU (one standard deviation). Two methods for the visualization of dose rate datasets were developed: the first method plots a two-dimensional (2D) histogram of the number of voxels receiving a given dose rate over the course of the arc treatment delivery. In similarity to treatment planning system display of dose, the second method displays the dose rate as color wash on top of the corresponding computed tomography image, allowing the user to scroll through the variation over time. Examining clinical cases showed dose rates spread over a continuous spectrum, with mean dose rates hardly exceeding 100 cGy min-1 for conventional

  10. Heart Rate and Respiratory Rate Influence on Heart Rate Variability Repeatability: Effects of the Correction for the Prevailing Heart Rate

    PubMed Central

    Gąsior, Jakub S.; Sacha, Jerzy; Jeleń, Piotr J.; Zieliński, Jakub; Przybylski, Jacek

    2016-01-01

    Background: Since heart rate variability (HRV) is associated with average heart rate (HR) and respiratory rate (RespRate), alterations in these parameters may impose changes in HRV. Hence the repeatability of HRV measurements may be affected by differences in HR and RespRate. The study aimed to evaluate HRV repeatability and its association with changes in HR and RespRate. Methods: Forty healthy volunteers underwent two ECG examinations 7 days apart. Standard HRV indices were calculated from 5-min ECG recordings. The ECG-derived respiration signal was estimated to assess RespRate. To investigate HR impact on HRV, HRV parameters were corrected for prevailing HR. Results: Differences in HRV parameters between the measurements were associated with the changes in HR and RespRate. However, in multiple regression analysis only HR alteration proved to be independent determinant of the HRV differences—every change in HR by 1 bpm changed HRV values by 16.5% on average. After overall removal of HR impact on HRV, coefficients of variation of the HRV parameters significantly dropped on average by 26.8% (p < 0.001), i.e., by the same extent HRV reproducibility improved. Additionally, the HRV correction for HR decreased association between RespRate and HRV. Conclusions: In stable conditions, HR but not RespRate is the most powerful factor determining HRV reproducibility and even a minimal change of HR may considerably alter HRV. However, the removal of HR impact may significantly improve HRV repeatability. The association between HRV and RespRate seems to be, at least in part, HR dependent. PMID:27588006

  11. Blood pressure responder rates versus goal rates: which metric matters?

    PubMed

    Basile, Jan

    2009-04-01

    Reducing blood pressure (BP) to guideline-recommended goals associated with reductions in cardiovascular risk is central to effective hypertension management. In addition to measuring BP reduction, clinical trials of antihypertensive agents should assess the percentage of patients responding to treatment. The Food and Drug Administration's defined rate of response required for drug approval is a reduction in diastolic BP (DBP) to <90 mmHg and/or a DBP reduction of > or = 10 mmHg. Consequently, some patients may be counted as responders even if they have not reached DBP <90 mmHg. An antihypertensive agent's effectiveness may be better assessed by the proportion of patients who achieve recommended BP goals. This article analyzes the frequency of response rates versus goal rates as endpoints in randomized trials since January 2001. Data showed that goal rates, especially combined systolic BP (SBP)/DBP goal rates, are consistently lower than response rates in studies evaluating both endpoints. Goal rates incorporating both SBP and DBP, or having a focus on SBP for individuals >50 years of age, provide the most clinically relevant information and are a more clinically relevant metric of an agent's ability to reduce BP than DBP alone.

  12. Overview of Field Experience - Degradation Rates & Lifetimes

    SciTech Connect

    Jordan, Dirk; Kurtz, Sarah

    2015-09-14

    The way a PV module fails may depend not only on its design and the materials used in its construction, but also on the weather it experiences, the way it is mounted, and the quality control during its manufacture. This presentation gives an overview of Field Experience - what degradation rates and what lifetimes are being observed in various regions.

  13. Test and Evaluation of Reduced Rate Multiplexers.

    DTIC Science & Technology

    1981-08-01

    modems. However, recognizing the potential economics that could result from operating at data rates lower than 64 KB/S, this T&E program is structured to...modulation transmitted as a vestigial . sideband line signal, -16 dB carrier 2853 Hz added in quadrature, 4 level 4800 baud 9600 BIS, 4800/7200/9600 B

  14. Rating scales and Rasch measurement.

    PubMed

    Andrich, David

    2011-10-01

    Assessments with ratings in ordered categories have become ubiquitous in health, biological and social sciences. Ratings are used when a measuring instrument of the kind found in the natural sciences is not available to assess some property in terms of degree - for example, greater or smaller, better or worse, or stronger or weaker. The handling of ratings has ranged from the very elementary to the highly sophisticated. In an elementary form, and assumed in classical test theory, the ratings are scored with successive integers and treated as measurements; in a sophisticated form, and used in modern test theory, the ratings are characterized by probabilistic response models with parameters for persons and the rating categories. Within modern test theory, two paradigms, similar in many details but incompatible on crucial points, have emerged. For the purposes of this article, these are termed the statistical modeling and experimental measurement paradigms. Rather than reviewing a compendium of available methods and models for analyzing ratings in detail, the article focuses on the incompatible differences between these two paradigms, with implications for choice of model and inferences. It shows that the differences have implications for different roles for substantive researchers and psychometricians in designing instruments with rating scales. To illustrate these differences, an example is provided.

  15. Quantum rate-distortion coding

    NASA Astrophysics Data System (ADS)

    Barnum, Howard

    2000-10-01

    I introduce rate-distortion theory for the coding of quantum information, and derive a lower bound, involving the coherent information, on the rate at which qubits must be used to store or compress an entangled quantum source with a given maximum level of distortion per source emission.

  16. Evolution & the Cesarean Section Rate

    ERIC Educational Resources Information Center

    Walsh, Joseph A.

    2008-01-01

    "Nothing in biology makes sense except in the light of evolution." This was the title of an essay by geneticist Theodosius Dobzhansky writing in 1973. Many causes have been given for the increased Cesarean section rate in developed countries, but biologic evolution has not been one of them. The C-section rate will continue to rise, because the…

  17. Value of IDEA Ratings Questioned

    ERIC Educational Resources Information Center

    Samuels, Christina A.

    2010-01-01

    Just as it has every June since 2006, the U.S. Department of Education last month delivered a rating to each state and territory based on the performance of its special education programs. The ratings, intended to fulfill the Individuals with Disabilities Education Act's requirement that "measurable" and "rigorous" targets be…

  18. Toronto bicycle commuter safety rates.

    PubMed

    Aultman-Hall, L; Kaltenecker, M G

    1999-11-01

    This analysis uses data from a survey of Toronto commuter cyclists that collected information regarding accident history as well as regular commute route to work or school. By relating the route information of the 1196 respondents to facility attributes in a Geographic Information System (GIS), defensible estimates of travel exposure on roads, off-road paths and sidewalks were developed. The rate of collision on off-road paths and sidewalks was lower than for roads. The relative rates for falls and injuries suggest these events are least common on-road followed by off-road paths, and finally most common on sidewalks. The rate of major injuries, an injury that required medical attention, was greatest on sidewalks and the difference between paths and sidewalks was negligible. These rates suggest a need for detailed analysis of sidewalk and off-road path bicycle safety. The absolute event rates per bicycle kilometer were found to be between 26 and 68 times higher than similar rates for automobile travel, re-confirming the urgent bicycle safety crisis. Examination of rates for sub-groups of cyclists suggest that experience is an important factor in bicycle safety. The same survey conducted in Ottawa, Canada found event rates much lower than Toronto. This result may confirm urban form, traffic levels and attitude do affect bicycle safety. The analysis also demonstrates a successful method to quantify bicycle travel exposure information and should be considered for further use as complement to other existing techniques.

  19. Value of IDEA Ratings Questioned

    ERIC Educational Resources Information Center

    Samuels, Christina A.

    2010-01-01

    Just as it has every June since 2006, the U.S. Department of Education last month delivered a rating to each state and territory based on the performance of its special education programs. The ratings, intended to fulfill the Individuals with Disabilities Education Act's requirement that "measurable" and "rigorous" targets be…

  20. Nontraditional Student Graduation Rate Benchmarks

    ERIC Educational Resources Information Center

    Miller, Nathan B.

    2014-01-01

    The prominence of discourse on postsecondary degree completion, student persistence, and retention has increased in the national dialogue. Heightened attention to college completion rates by the federal government and pressure to tie state funding to performance metrics associated with graduation rates are catalysts for the discussion.…

  1. Predicting the Divorce Rate: Down?

    ERIC Educational Resources Information Center

    Kemper, Theodore D.

    1983-01-01

    Predicted a decline in the divorce rate based on 10 factors including: decline in marriage rate, older age at marriage, mental health improvement, upper limit on employed women, less migration, end of the cultural revolution, exhaustion of latency effect of no-fault divorce, and fear of the consequences of divorce. (JAC)

  2. Mutation Rates among RNA Viruses

    NASA Astrophysics Data System (ADS)

    Drake, John W.; Holland, John J.

    1999-11-01

    The rate of spontaneous mutation is a key parameter in modeling the genetic structure and evolution of populations. The impact of the accumulated load of mutations and the consequences of increasing the mutation rate are important in assessing the genetic health of populations. Mutation frequencies are among the more directly measurable population parameters, although the information needed to convert them into mutation rates is often lacking. A previous analysis of mutation rates in RNA viruses (specifically in riboviruses rather than retroviruses) was constrained by the quality and quantity of available measurements and by the lack of a specific theoretical framework for converting mutation frequencies into mutation rates in this group of organisms. Here, we describe a simple relation between ribovirus mutation frequencies and mutation rates, apply it to the best (albeit far from satisfactory) available data, and observe a central value for the mutation rate per genome per replication of μ g≈ 0.76. (The rate per round of cell infection is twice this value or about 1.5.) This value is so large, and ribovirus genomes are so informationally dense, that even a modest increase extinguishes the population.

  3. Rating Openness: A Training Manual.

    ERIC Educational Resources Information Center

    Strachan, Angus; And Others

    This training manual explains the process of rating client openness from a short sample of dyadic help-intended interactions. The overview of client openness includes a discussion of the 10-week undergraduate program which teaches students to assess client openness based on behavioral ratings from the Group Assessment of Interpersonal Traits…

  4. Matching and Conditioned Reinforcement Rate

    ERIC Educational Resources Information Center

    Shahan, Timothy A.; Podlesnik, Christopher A.; Jimenez-Gomez, Corina

    2006-01-01

    Attempts to examine the effects of variations in relative conditioned reinforcement rate on choice have been confounded by changes in rates of primary reinforcement or changes in the value of the conditioned reinforcer. To avoid these problems, this experiment used concurrent observing responses to examine sensitivity of choice to relative…

  5. Matching and Conditioned Reinforcement Rate

    ERIC Educational Resources Information Center

    Shahan, Timothy A.; Podlesnik, Christopher A.; Jimenez-Gomez, Corina

    2006-01-01

    Attempts to examine the effects of variations in relative conditioned reinforcement rate on choice have been confounded by changes in rates of primary reinforcement or changes in the value of the conditioned reinforcer. To avoid these problems, this experiment used concurrent observing responses to examine sensitivity of choice to relative…

  6. Evolution & the Cesarean Section Rate

    ERIC Educational Resources Information Center

    Walsh, Joseph A.

    2008-01-01

    "Nothing in biology makes sense except in the light of evolution." This was the title of an essay by geneticist Theodosius Dobzhansky writing in 1973. Many causes have been given for the increased Cesarean section rate in developed countries, but biologic evolution has not been one of them. The C-section rate will continue to rise, because the…

  7. The Psychological Maltreatment Rating Scales.

    ERIC Educational Resources Information Center

    Brassard, Marla R.; And Others

    1993-01-01

    The Psychological Maltreatment Rating Scales (PMRS) were developed for assessing psychological maltreatment in the mother-child interaction, and were used to rate the videotaped interaction of 49 high-risk mother-child dyads and predict child protective service involvements. The PMRS was found to be a moderately reliable and valid measure.…

  8. Descriptive Analysis of Student Ratings

    ERIC Educational Resources Information Center

    Marasini, Donata; Quatto, Piero

    2011-01-01

    Let X be a statistical variable representing student ratings of University teaching. It is natural to assume for X an ordinal scale consisting of k categories (in ascending order of satisfaction). At first glance, student ratings can be summarized by a location index (such as the mode or the median of X) associated with a convenient measure of…

  9. Amniotic fluid embolism mortality rate.

    PubMed

    Benson, Michael D

    2017-08-17

    The objective of this study was to determine the mortality rate of amniotic fluid embolism (AFE) using population-based studies and case series. A literature search was conducted using the two key words: 'amniotic fluid embolism (AFE)' AND 'mortality rate'. Thirteen population-based studies were evaluated, as well as 36 case series including at least two patients. The mortality rate from population-based studies varied from 11% to 44%. When nine population-based studies with over 17 000 000 live births were aggregated, the maternal mortality rate was 20.4%. In contrast, the mortality rate of AFE in case series varies from 0% to 100% with numerous rates in between. The AFE mortality rate in population-based studies varied from 11% to 44% with the best available evidence supporting an overall mortality rate of 20.4%. Data from case series should no longer be used as a basis for describing the lethality of AFE. © 2017 Japan Society of Obstetrics and Gynecology.

  10. What Is a Reaction Rate?

    ERIC Educational Resources Information Center

    Schmitz, Guy

    2005-01-01

    The definition of reaction rate is derived and demonstrations are made for the care to be taken while using the term. Reaction rate can be in terms of a reaction property, the extent of reaction and thus it is possible to give a definition applicable in open and closed systems.

  11. Predicting the Divorce Rate: Down?

    ERIC Educational Resources Information Center

    Kemper, Theodore D.

    1983-01-01

    Predicted a decline in the divorce rate based on 10 factors including: decline in marriage rate, older age at marriage, mental health improvement, upper limit on employed women, less migration, end of the cultural revolution, exhaustion of latency effect of no-fault divorce, and fear of the consequences of divorce. (JAC)

  12. Pontomedullary transection attenuates central respiratory modulation of sympathetic discharge, heart rate and the baroreceptor reflex in the in situ rat preparation.

    PubMed

    Baekey, David M; Dick, Thomas E; Paton, Julian F R

    2008-07-01

    Previous studies have indicated a major role for the pons in the genesis of the respiratory pattern. The respiratory rhythm is coupled to the cardiovascular system to ensure optimal matching of minute ventilation and cardiac output. Since much of this coupling results from cross-talk between brainstem circuits, we have assessed the role of the pons in both the co-ordination of respiratory and cardiovascular efferent activities and the baroreceptor reflex efficacy. Using the arterially perfused in situ rat preparation, we recorded neural activities from the left phrenic nerve, central end of the vagus nerve, thoracic sympathetic chain (T8-T10) and heart rate. Respiratory sinus arrhythmia, respiratory modulation of sympathetic nerve activity (and Traube-Hering waves in arterial pressure) and postinspiratory discharges recorded from vagal efferents were eliminated after pontine transection. We also found that although the sympathetic arterial baroreflex remained intact, respiratory gating of the baroreceptor reflex (i.e. both bradycardia and sympathoinhibition) was abolished after pontine removal. We propose that neural activity of the pons is essential for physiological coupling of centrally generated respiratory and cardiovascular efferent activities.

  13. Comment on 'Time modulation of K-shell electron capture decay rates of H-like heavy ions at GSI experiments.'

    SciTech Connect

    Lipkin, H. J.; Physics; Weizmann Inst. of Science; Tel Aviv Univ.

    2010-04-16

    A Comment on the Letter by A.N. Ivanov and P. Kienle, Physical Review Letters volume 103, Issue 6, 062502 (2009). The authors of the Letter offer a Reply to experimental data at GSI, the rates of the number of daughter ions, produced by the nuclear K shell electron capture decays of the H-like heavy ions with one electron in the K shell, such as {sup 140}Pr{sup 58+}, {sup 142}Pm{sup 60+}, and {sup 122}I{sup 52+}, are modulated in time with periods T{sub EC} of the order of a few seconds, obeying an A scaling T{sub EX}=A/20 s, where A is the mass number of the mother nuclei, and with amplitudes a{sub d {sup EC}}{approx}0.21. We show that these data can be explained in terms of the interference of two massive neutrino mass eigenstates. The appearance of the interference term is due to overlap of massive neutrino mass eigenstate energies and of the wave functions of the daughter ions in two-body decay channels, caused by the energy and momentum uncertainties introduced by time differential detection of the daughter ions in GSI experiments.

  14. New fine structure cooling rate

    NASA Technical Reports Server (NTRS)

    Hoegy, W. R.

    1976-01-01

    One of the dominant electron cooling processes in the ionosphere is caused by electron impact induced fine structure transitions among the ground state levels of atomic oxygen. This fine structure cooling rate is based on theoretical cross sections. Recent advances in the numerical cross section determinations to include polarization effects and more accurate representations of the atomic target result in new lower values. These cross sections are employed in this paper to derive a new fine structure cooling rate which is between 40% and 60% of the currently used rate. A new generalized formula is presented for the cooling rate (from which the fine structure cooling rate is derived), valid for arbitrary mass and temperature difference of the colliding particles and arbitrary inelastic energy difference.

  15. The Logic of Collective Rating

    NASA Astrophysics Data System (ADS)

    Nax, Heinrich

    2016-05-01

    The introduction of participatory rating mechanisms on online sales platforms has had substantial impact on firms' sales and profits. In this note, we develop a dynamic model of consumer influences on ratings and of rating influences on consumers, focussing on standard 5-star mechanisms as implemented by many platforms. The key components of our social influence model are the consumer trust in the `wisdom of crowds' during the purchase phase and indirect reciprocity during the rating decision. Our model provides an overarching explanation for well-corroborated empirical regularities. We quantify the performance of the voluntary rating mechanism in terms of realized consumer surplus with the no-mechanism and full-information benchmarks, and identify how it could be improved.

  16. Innovative Rates Program. Final report

    SciTech Connect

    Not Available

    1982-06-21

    Title II of the Energy Conservation and Production Act (ECPA) as amended by the Public Utility Regulatory Policies Act (PURPA) provided financial assistance to state utility regulatory commissions, nonregulated electric utilities, and the Tennessee Valley Authority through the Innovative Rates Program. The financial assistance was to be used to plan or carry out electric utility regulatory rate reform initiatives relating to innovative rate structures that encourage conservation of energy, electric utility efficiency and reduced costs, and equitable rates to consumers. The Federal and local objectives of the project are described. Activities planned and accomplishments are summarized for the following: project management, data collection, utility bill evaluation, billing enclosure/mailing evaluation, media program evaluation, display evaluation, rate study sessions evaluation, speakers bureau evaluation, and individual customer contacts. A timetable/milestone chart and financial information are included. (MHR)

  17. Heart Rate Variability Analysis in General Medicine

    PubMed Central

    Gang, Yi; Malik, Marek

    2003-01-01

    Autonomic nervous system plays an integral role in homeostasis. Autonomic modulation can frequently be altered in patients with cardiac disorders as well as in patients with other critical illnesses or injuries. Assessment of heart rate variability is based on analysis of consecutive normal R-R intervals and may provide quantitative information on the modulation of cardiac vagal and sympathetic nerve input. The hypothesis that depressed heart rate variability may occur over a broad range of illness and injury, and may inversely correlated with disease severity and outcome has been tested in various clinical settings over the last decade. This article reviews recent literature concerning the potential clinical implications and limitations of heart rate variability assessment in general medicine. PMID:16943988

  18. The Average of Rates and the Average Rate.

    ERIC Educational Resources Information Center

    Lindstrom, Peter

    1988-01-01

    Defines arithmetic, harmonic, and weighted harmonic means, and discusses their properties. Describes the application of these properties in problems involving fuel economy estimates and average rates of motion. Gives example problems and solutions. (CW)

  19. The Average of Rates and the Average Rate.

    ERIC Educational Resources Information Center

    Lindstrom, Peter

    1988-01-01

    Defines arithmetic, harmonic, and weighted harmonic means, and discusses their properties. Describes the application of these properties in problems involving fuel economy estimates and average rates of motion. Gives example problems and solutions. (CW)

  20. The Airline Quality Rating 2001

    NASA Technical Reports Server (NTRS)

    Bowen, Brent D.; Headley, Dean E.

    2001-01-01

    The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, Airline Quality Rating 2001, reflects monthly Airline Quality Rating scores for 2000. AQR scores for the calendar year 2000 are based on 15 elements that focus on airline performance areas important to air travel consumers. The Airline Quality Rating 2001 is a summary of month-by-month quality ratings for the ten major U.S. airlines operating during 2000. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of on-time arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, major airlines comparative performance for the calendar year of 2000 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for major airlines domestic operations for the 12 month period of 2000, and industry average results. Also, comparative Airline Quality Rating data for 1999 are included for each airline to provide historical perspective regarding performance quality in the industry.

  1. The Airline Quality Rating 2003

    NASA Technical Reports Server (NTRS)

    Bowen, Brent D.; Headley, Dean E.

    2003-01-01

    The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, the Airline Quality Rating 2003, reflects monthly Airline Quality Rating scores for 2002. AQR scores for the calendar year 2002 are based on 15 elements that focus on airline performance areas important to air travel consumers. The Airline Quality Rating 2003 is a summary of month-by-month quality ratings for the 10 largest U.S. airlines operating during 2002. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of ontime arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, airlines comparative performance for the calendar year of 2002 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for domestic airline operations for the 12-month period of 2002, and industry average results. Also, comparative Airline Quality Rating data for 2001 are included for each airline to provide historical perspective regarding performance quality in the industry.

  2. The Airline Quality Rating 2004

    NASA Technical Reports Server (NTRS)

    Fink, Mary M. (Editor); Bowen, Brent D.; Headley, Dean E.

    2004-01-01

    The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, the Airline Quality Rating 2004, reflects monthly Airline Quality Rating scores for 2003. AQR scores for the calendar year 2003 are based on 15 elements in four major areas that focus on airline performance aspects important to air travel consumers. The Airline Quality Rating 2004 is a summary of month-by-month quality ratings for U.S. airlines that have at least 1 % of domestic passenger volume during 2003. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of on-time arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, airlines comparative performance for the calendar year of 2003 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for domestic airline operations for the 12-month period of 2003, and industry results. Also, comparative Airline Quality Rating data for 2002 are included, where available, to provide historical perspective regarding performance quality in the industry.

  3. The Airline Quality Rating 2004

    NASA Technical Reports Server (NTRS)

    Fink, Mary M. (Editor); Bowen, Brent D.; Headley, Dean E.

    2004-01-01

    The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, the Airline Quality Rating 2004, reflects monthly Airline Quality Rating scores for 2003. AQR scores for the calendar year 2003 are based on 15 elements in four major areas that focus on airline performance aspects important to air travel consumers. The Airline Quality Rating 2004 is a summary of month-by-month quality ratings for U.S. airlines that have at least 1 % of domestic passenger volume during 2003. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of on-time arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, airlines comparative performance for the calendar year of 2003 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for domestic airline operations for the 12-month period of 2003, and industry results. Also, comparative Airline Quality Rating data for 2002 are included, where available, to provide historical perspective regarding performance quality in the industry.

  4. The Airline Quality Rating 2003

    NASA Technical Reports Server (NTRS)

    Bowen, Brent D.; Headley, Dean E.

    2003-01-01

    The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, the Airline Quality Rating 2003, reflects monthly Airline Quality Rating scores for 2002. AQR scores for the calendar year 2002 are based on 15 elements that focus on airline performance areas important to air travel consumers. The Airline Quality Rating 2003 is a summary of month-by-month quality ratings for the 10 largest U.S. airlines operating during 2002. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of ontime arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, airlines comparative performance for the calendar year of 2002 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for domestic airline operations for the 12-month period of 2002, and industry average results. Also, comparative Airline Quality Rating data for 2001 are included for each airline to provide historical perspective regarding performance quality in the industry.

  5. The Airline Quality Rating 2004

    NASA Technical Reports Server (NTRS)

    Bowen, Brent D.; Headley, Dean E.

    2004-01-01

    The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, the Airline Quality Rating 2004, reflects monthly Airline Quality Rating scores for 2003. AQR scores far the calendar year 2003 are based on 15 elemnts in four major areas that focus on airline performance aspects important to air travel consumers. The Airline Quality Rating 2004 is a summary of month-by-month quality ratings for U.S. airlines that have at least 1% of domestic passenger volume during 2003. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of on-time arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, airlines comparative performance for the calendar year of 2003 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for domestic airline operations for the 12-month period of 2003, and industry results. Also, comparative Airline Quality Rating data for 2002 are included, where available, to provide historical perspective

  6. Heart rates during competitive orienteering.

    PubMed

    Bird, S R; Bailey, R; Lewis, J

    1993-03-01

    This study investigated the heart rate profiles of 16 experienced, competitive orienteers (aged 15-62 years) during three competitive events. Each competitor was assessed over three different types of course which were classified as: fast run (FR), slow run (SR) and highly physical (HP). The results showed that all subjects recorded heart rates that were between 140 and 180 beats min-1 for the majority of each event (irrespective of age or course type). The heart rate data indicated that the activity was largely aerobic but varied in intensity, with phases of strenuous anaerobic work. The type of course was shown significantly (analysis of variance; P < 0.001) to affect the mean heart rate attained by each orienteer (FR = 160, HP = 158, SR = 150 beats min-1), with courses that required more technical skill and hence slower running producing lower mean heart rates; although the general physical demands were similar for all courses. The older orienteers (> 45 years) recorded heart rate profiles that were similar to those of the young orienteers with no correlation being found between age and mean heart rate while exercising.

  7. Heart rates during competitive orienteering.

    PubMed Central

    Bird, S R; Bailey, R; Lewis, J

    1993-01-01

    This study investigated the heart rate profiles of 16 experienced, competitive orienteers (aged 15-62 years) during three competitive events. Each competitor was assessed over three different types of course which were classified as: fast run (FR), slow run (SR) and highly physical (HP). The results showed that all subjects recorded heart rates that were between 140 and 180 beats min-1 for the majority of each event (irrespective of age or course type). The heart rate data indicated that the activity was largely aerobic but varied in intensity, with phases of strenuous anaerobic work. The type of course was shown significantly (analysis of variance; P < 0.001) to affect the mean heart rate attained by each orienteer (FR = 160, HP = 158, SR = 150 beats min-1), with courses that required more technical skill and hence slower running producing lower mean heart rates; although the general physical demands were similar for all courses. The older orienteers (> 45 years) recorded heart rate profiles that were similar to those of the young orienteers with no correlation being found between age and mean heart rate while exercising. PMID:8457815

  8. The Airline Quality Rating 1999

    NASA Technical Reports Server (NTRS)

    Bowen, Brent D.; Headley, Dean E.

    1999-01-01

    The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline performance on combined multiple criteria. This current report, Airline Quality Rating 1999, reflects an updated approach to calculating monthly Airline Quality Rating scores for 1998. AQR scores for the calendar year 1998 are based on 15 elements that focus on airline performance areas important to air travel consumers. The Airline Quality Rating is a summary of month-by-month quality ratings for the ten major U.S. airlines operating during 1998. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of on-time arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, major airlines comparative performance for the calendar year 1998 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for major airlines domestic operations for the 12 month period of 1998, and industry average results. Also, comparative Airline Quality Rating data for 1997, using the updated criteria, are included to provide a reference point regarding quality in the industry.

  9. The Airline Quality Rating 2002

    NASA Technical Reports Server (NTRS)

    Bowen, Brent D.; Headley, Dean E.

    2002-01-01

    The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, Airline Quality Rating 2002, reflects monthly Airline Quality Rating scores for 2001. AQR scores for the calendar year 2001 are based on 15 elements that focus on airline performance areas important to air travel consumers. The Airline Quality Rating 2002 is a summary of month-by-month quality ratings for the 11 largest U.S. airlines operating during 2001. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of on-time arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, airlines comparative performance for the calendar year of 2001 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for domestic airline operations for the 12-month period of 2001, and industry average results. Also, comparative Airline Quality Rating data for 2000 are included for each airline to provide historical perspective regarding performance quality in the industry.

  10. [Design of Oxygen Saturation, Heart Rate, Respiration Rate Detection System Based on Smartphone of Android Operating System].

    PubMed

    Zhu, Mingshan; Zeng, Bixin

    2015-03-01

    In this paper, we designed an oxygen saturation, heart rate, respiration rate monitoring system based on smartphone of android operating system, physiological signal acquired by MSP430 microcontroller and transmitted by Bluetooth module.

  11. 76 FR 8946 - Security Ratings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-16

    ...This is one of several releases that we will be considering relating to the use of security ratings by credit rating agencies in our rules and forms. In this release, pursuant to the provisions of Section 939A of the Dodd-Frank Wall Street Reform and Consumer Protection Act, we propose to replace rule and form requirements under the Securities Act of 1933 and the Securities Exchange Act of 1934 for securities offering or issuer disclosure rules that rely on, or make special accommodations for, security ratings (for example, Forms S-3 and F-3 eligibility criteria) with alternative requirements.

  12. 78 FR 62627 - Sam Rayburn Dam Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-22

    ... pursuant to the following rate schedule: Rate Schedule SRD-13, Wholesale Rates for Hydro Power and Energy... supersedes the existing rate schedule shown below: Rate Schedule SRD-08, Wholesale Rates for Hydro Power and... SOUTHWESTERN POWER ADMINISTRATION RATE SCHEDULE SRD-13 \\1\\ WHOLESALE RATES FOR HYDRO POWER AND ENERGY SOLD...

  13. Correlation between gamma index passing rate and clinical dosimetric difference for pre-treatment 2D and 3D volumetric modulated arc therapy dosimetric verification.

    PubMed

    Jin, X; Yan, H; Han, C; Zhou, Y; Yi, J; Xie, C

    2015-03-01

    To investigate comparatively the percentage gamma passing rate (%GP) of two-dimensional (2D) and three-dimensional (3D) pre-treatment volumetric modulated arc therapy (VMAT) dosimetric verification and their correlation and sensitivity with percentage dosimetric errors (%DE). %GP of 2D and 3D pre-treatment VMAT quality assurance (QA) with different acceptance criteria was obtained by ArcCHECK® (Sun Nuclear Corporation, Melbourne, FL) for 20 patients with nasopharyngeal cancer (NPC) and 20 patients with oesophageal cancer. %DE were calculated from planned dose-volume histogram (DVH) and patients' predicted DVH calculated by 3DVH® software (Sun Nuclear Corporation). Correlation and sensitivity between %GP and %DE were investigated using Pearson's correlation coefficient (r) and receiver operating characteristics (ROCs). Relatively higher %DE on some DVH-based metrics were observed for both patients with NPC and oesophageal cancer. Except for 2%/2 mm criterion, the average %GPs for all patients undergoing VMAT were acceptable with average rates of 97.11% ± 1.54% and 97.39% ± 1.37% for 2D and 3D 3%/3 mm criteria, respectively. The number of correlations for 3D was higher than that for 2D (21 vs 8). However, the general correlation was still poor for all the analysed metrics (9 out of 26 for 3D 3%/3 mm criterion). The average area under the curve (AUC) of ROCs was 0.66 ± 0.12 and 0.71 ± 0.21 for 2D and 3D evaluations, respectively. There is a lack of correlation between %GP and %DE for both 2D and 3D pre-treatment VMAT dosimetric evaluation. DVH-based dose metrics evaluation obtained from 3DVH will provide more useful analysis. Correlation and sensitivity of %GP with %DE for VMAT QA were studied for the first time.

  14. Correlation between gamma index passing rate and clinical dosimetric difference for pre-treatment 2D and 3D volumetric modulated arc therapy dosimetric verification

    PubMed Central

    Jin, X; Yan, H; Han, C; Zhou, Y; Yi, J

    2015-01-01

    Objective: To investigate comparatively the percentage gamma passing rate (%GP) of two-dimensional (2D) and three-dimensional (3D) pre-treatment volumetric modulated arc therapy (VMAT) dosimetric verification and their correlation and sensitivity with percentage dosimetric errors (%DE). Methods: %GP of 2D and 3D pre-treatment VMAT quality assurance (QA) with different acceptance criteria was obtained by ArcCHECK® (Sun Nuclear Corporation, Melbourne, FL) for 20 patients with nasopharyngeal cancer (NPC) and 20 patients with oesophageal cancer. %DE were calculated from planned dose–volume histogram (DVH) and patients' predicted DVH calculated by 3DVH® software (Sun Nuclear Corporation). Correlation and sensitivity between %GP and %DE were investigated using Pearson's correlation coefficient (r) and receiver operating characteristics (ROCs). Results: Relatively higher %DE on some DVH-based metrics were observed for both patients with NPC and oesophageal cancer. Except for 2%/2 mm criterion, the average %GPs for all patients undergoing VMAT were acceptable with average rates of 97.11% ± 1.54% and 97.39% ± 1.37% for 2D and 3D 3%/3 mm criteria, respectively. The number of correlations for 3D was higher than that for 2D (21 vs 8). However, the general correlation was still poor for all the analysed metrics (9 out of 26 for 3D 3%/3 mm criterion). The average area under the curve (AUC) of ROCs was 0.66 ± 0.12 and 0.71 ± 0.21 for 2D and 3D evaluations, respectively. Conclusions: There is a lack of correlation between %GP and %DE for both 2D and 3D pre-treatment VMAT dosimetric evaluation. DVH-based dose metrics evaluation obtained from 3DVH will provide more useful analysis. Advances in knowledge: Correlation and sensitivity of %GP with %DE for VMAT QA were studied for the first time. PMID:25494412

  15. A radiative transfer module for calculating photolysis rates and solar heating in climate models: Solar-J v7.5

    DOE PAGES

    Hsu, Juno; Prather, Michael J.; Cameron-Smith, Philip; ...

    2017-01-01

    Solar-J is a comprehensive radiative transfer model for the solar spectrum that addresses the needs of both solar heating and photochemistry in Earth system models. Solar-J is a spectral extension of Cloud-J, a standard in many chemical models that calculates photolysis rates in the 0.18–0.8 µm region. The Cloud-J core consists of an eight-stream scattering, plane-parallel radiative transfer solver with corrections for sphericity. Cloud-J uses cloud quadrature to accurately average over correlated cloud layers. It uses the scattering phase function of aerosols and clouds expanded to eighth order and thus avoids isotropic-equivalent approximations prevalent in most solar heating codes. Themore » spectral extension from 0.8 to 12 µm enables calculation of both scattered and absorbed sunlight and thus aerosol direct radiative effects and heating rates throughout the Earth's atmosphere. Furthermore, the Solar-J extension adopts the correlated-k gas absorption bins, primarily water vapor, from the shortwave Rapid Radiative Transfer Model for general circulation model (GCM) applications (RRTMG-SW). Solar-J successfully matches RRTMG-SW's tropospheric heating profile in a clear-sky, aerosol-free, tropical atmosphere. Here, we compare both codes in cloudy atmospheres with a liquid-water stratus cloud and an ice-crystal cirrus cloud. For the stratus cloud, both models use the same physical properties, and we find a systematic low bias of about 3 % in planetary albedo across all solar zenith angles caused by RRTMG-SW's two-stream scattering. Discrepancies with the cirrus cloud using any of RRTMG-SW's three different parameterizations are as large as about 20–40 % depending on the solar zenith angles and occur throughout the atmosphere. Effectively, Solar-J has combined the best components of RRTMG-SW and Cloud-J to build a high-fidelity module for the scattering and absorption of sunlight in the Earth's atmosphere, for which the three major components – wavelength

  16. A radiative transfer module for calculating photolysis rates and solar heating in climate models: Solar-J v7.5

    SciTech Connect

    Hsu, Juno; Prather, Michael J.; Cameron-Smith, Philip; Veidenbaum, Alex; Nicolau, Alex

    2017-01-01

    Solar-J is a comprehensive radiative transfer model for the solar spectrum that addresses the needs of both solar heating and photochemistry in Earth system models. Solar-J is a spectral extension of Cloud-J, a standard in many chemical models that calculates photolysis rates in the 0.18–0.8 µm region. The Cloud-J core consists of an eight-stream scattering, plane-parallel radiative transfer solver with corrections for sphericity. Cloud-J uses cloud quadrature to accurately average over correlated cloud layers. It uses the scattering phase function of aerosols and clouds expanded to eighth order and thus avoids isotropic-equivalent approximations prevalent in most solar heating codes. The spectral extension from 0.8 to 12 µm enables calculation of both scattered and absorbed sunlight and thus aerosol direct radiative effects and heating rates throughout the Earth's atmosphere. Furthermore, the Solar-J extension adopts the correlated-k gas absorption bins, primarily water vapor, from the shortwave Rapid Radiative Transfer Model for general circulation model (GCM) applications (RRTMG-SW). Solar-J successfully matches RRTMG-SW's tropospheric heating profile in a clear-sky, aerosol-free, tropical atmosphere. Here, we compare both codes in cloudy atmospheres with a liquid-water stratus cloud and an ice-crystal cirrus cloud. For the stratus cloud, both models use the same physical properties, and we find a systematic low bias of about 3 % in planetary albedo across all solar zenith angles caused by RRTMG-SW's two-stream scattering. Discrepancies with the cirrus cloud using any of RRTMG-SW's three different parameterizations are as large as about 20–40 % depending on the solar zenith angles and occur throughout the atmosphere. Effectively, Solar-J has combined the best components of RRTMG-SW and Cloud-J to build a high-fidelity module for the scattering and absorption of sunlight in the Earth's atmosphere, for which the three major components – wavelength

  17. A radiative transfer module for calculating photolysis rates and solar heating in climate models: Solar-J v7.5

    NASA Astrophysics Data System (ADS)

    Hsu, Juno; Prather, Michael J.; Cameron-Smith, Philip; Veidenbaum, Alex; Nicolau, Alex

    2017-07-01

    Solar-J is a comprehensive radiative transfer model for the solar spectrum that addresses the needs of both solar heating and photochemistry in Earth system models. Solar-J is a spectral extension of Cloud-J, a standard in many chemical models that calculates photolysis rates in the 0.18-0.8 µm region. The Cloud-J core consists of an eight-stream scattering, plane-parallel radiative transfer solver with corrections for sphericity. Cloud-J uses cloud quadrature to accurately average over correlated cloud layers. It uses the scattering phase function of aerosols and clouds expanded to eighth order and thus avoids isotropic-equivalent approximations prevalent in most solar heating codes. The spectral extension from 0.8 to 12 µm enables calculation of both scattered and absorbed sunlight and thus aerosol direct radiative effects and heating rates throughout the Earth's atmosphere.The Solar-J extension adopts the correlated-k gas absorption bins, primarily water vapor, from the shortwave Rapid Radiative Transfer Model for general circulation model (GCM) applications (RRTMG-SW). Solar-J successfully matches RRTMG-SW's tropospheric heating profile in a clear-sky, aerosol-free, tropical atmosphere. We compare both codes in cloudy atmospheres with a liquid-water stratus cloud and an ice-crystal cirrus cloud. For the stratus cloud, both models use the same physical properties, and we find a systematic low bias of about 3 % in planetary albedo across all solar zenith angles caused by RRTMG-SW's two-stream scattering. Discrepancies with the cirrus cloud using any of RRTMG-SW's three different parameterizations are as large as about 20-40 % depending on the solar zenith angles and occur throughout the atmosphere.Effectively, Solar-J has combined the best components of RRTMG-SW and Cloud-J to build a high-fidelity module for the scattering and absorption of sunlight in the Earth's atmosphere, for which the three major components - wavelength integration, scattering, and

  18. TRMM Sees Chantal's Rainfall Rates

    NASA Image and Video Library

    On July 8, NASA's TRMM satellite saw Tropical Storm Chantal's heaviest rainfall happening at a rate of over 115.5 mm/hr. (~4.5 inches) near Chantal's center where thunderstorms reached heights of o...

  19. Documentation for POTW Removal Rates

    EPA Pesticide Factsheets

    Table VI of the RFI presents removal and destruction rates for toxic chemicals sent to POTWs, based on experimental and estimated data compiled by the Risk-Screening Environmental Indicators (RSEI) Program.

  20. Reduced rates for AIP journals

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    The American Institute of Physics (AIP) offers reduced rates for subscriptions of its journals to individual members of affiliated societies. AGU is an A IP-affiliated society. The offer is limited to one subscription per person to each journal.