WorldWideScience

Sample records for variable rate playback

  1. Feasibility of video codec algorithms for software-only playback

    Science.gov (United States)

    Rodriguez, Arturo A.; Morse, Ken

    1994-05-01

    Software-only video codecs can provide good playback performance in desktop computers with a 486 or 68040 CPU running at 33 MHz without special hardware assistance. Typically, playback of compressed video can be categorized into three tasks: the actual decoding of the video stream, color conversion, and the transfer of decoded video data from system RAM to video RAM. By current standards, good playback performance is the decoding and display of video streams of 320 by 240 (or larger) compressed frames at 15 (or greater) frames-per- second. Software-only video codecs have evolved by modifying and tailoring existing compression methodologies to suit video playback in desktop computers. In this paper we examine the characteristics used to evaluate software-only video codec algorithms, namely: image fidelity (i.e., image quality), bandwidth (i.e., compression) ease-of-decoding (i.e., playback performance), memory consumption, compression to decompression asymmetry, scalability, and delay. We discuss the tradeoffs among these variables and the compromises that can be made to achieve low numerical complexity for software-only playback. Frame- differencing approaches are described since software-only video codecs typically employ them to enhance playback performance. To complement other papers that appear in this session of the Proceedings, we review methods derived from binary pattern image coding since these methods are amenable for software-only playback. In particular, we introduce a novel approach called pixel distribution image coding.

  2. An extended framework for adaptive playback-based video summarization

    Science.gov (United States)

    Peker, Kadir A.; Divakaran, Ajay

    2003-11-01

    In our previous work, we described an adaptive fast playback framework for video summarization where we changed the playback rate using the motion activity feature so as to maintain a constant "pace." This method provides an effective way of skimming through video, especially when the motion is not too complex and the background is mostly still, such as in surveillance video. In this paper, we present an extended summarization framework that, in addition to motion activity, uses semantic cues such as face or skin color appearance, speech and music detection, or other domain dependent semantically significant events to control the playback rate. The semantic features we use are computationally inexpensive and can be computed in compressed domain, yet are robust, reliable, and have a wide range of applicability across different content types. The presented framework also allows for adaptive summaries based on preference, for example, to include more dramatic vs. action elements, or vice versa. The user can switch at any time between the skimming and the normal playback modes. The continuity of the video is preserved, and complete omission of segments that may be important to the user is avoided by using adaptive fast playback instead of skipping over long segments. The rule-set and the input parameters can be further modified to fit a certain domain or application. Our framework can be used by itself, or as a subsequent presentation stage for a summary produced by any other summarization technique that relies on generating a sub-set of the content.

  3. Simulated birdwatchers' playback affects the behavior of two tropical birds.

    Science.gov (United States)

    Harris, J Berton C; Haskell, David G

    2013-01-01

    Although recreational birdwatchers may benefit conservation by generating interest in birds, they may also have negative effects. One such potentially negative impact is the widespread use of recorded vocalizations, or "playback," to attract birds of interest, including range-restricted and threatened species. Although playback has been widely used to test hypotheses about the evolution of behavior, no peer-reviewed study has examined the impacts of playback in a birdwatching context on avian behavior. We studied the effects of simulated birdwatchers' playback on the vocal behavior of Plain-tailed Wrens Thryothorus euophrys and Rufous Antpittas Grallaria rufula in Ecuador. Study species' vocal behavior was monitored for an hour after playing either a single bout of five minutes of song or a control treatment of background noise. We also studied the effects of daily five minute playback on five groups of wrens over 20 days. In single bout experiments, antpittas made more vocalizations of all types, except for trills, after playback compared to controls. Wrens sang more duets after playback, but did not produce more contact calls. In repeated playback experiments, wren responses were strong at first, but hardly detectable by day 12. During the study, one study group built a nest, apparently unperturbed, near a playback site. The playback-induced habituation and changes in vocal behavior we observed suggest that scientists should consider birdwatching activity when selecting research sites so that results are not biased by birdwatchers' playback. Increased vocalizations after playback could be interpreted as a negative effect of playback if birds expend energy, become stressed, or divert time from other activities. In contrast, the habituation we documented suggests that frequent, regular birdwatchers' playback may have minor effects on wren behavior.

  4. The influence of motion quality on responses towards video playback stimuli

    Directory of Open Access Journals (Sweden)

    Emma Ware

    2015-07-01

    Full Text Available Visual motion, a critical cue in communication, can be manipulated and studied using video playback methods. A primary concern for the video playback researcher is the degree to which objects presented on video appear natural to the non-human subject. Here we argue that the quality of motion cues on video, as determined by the video's image presentation rate (IPR, are of particular importance in determining a subject's social response behaviour. We present an experiment testing the effect of variations in IPR on pigeon (Columbia livia response behaviour towards video images of courting opposite sex partners. Male and female pigeons were presented with three video playback stimuli, each containing a different social partner. Each stimulus was then modified to appear at one of three IPRs: 15, 30 or 60 progressive (p frames per second. The results showed that courtship behaviour became significantly longer in duration as IPR increased. This finding implies that the IPR significantly affects the perceived quality of motion cues impacting social behaviour. In males we found that the duration of courtship also depended on the social partner viewed and that this effect interacted with the effects of IPR on behaviour. Specifically, the effect of social partner reached statistical significance only when the stimuli were displayed at 60 p, demonstrating the potential for erroneous results when insufficient IPRs are used. In addition to demonstrating the importance of IPR in video playback experiments, these findings help to highlight and describe the role of visual motion processing in communication behaviour.

  5. A Dynamic Programming Solution for Energy-Optimal Video Playback on Mobile Devices

    Directory of Open Access Journals (Sweden)

    Minseok Song

    2016-01-01

    Full Text Available Due to the development of mobile technology and wide availability of smartphones, the Internet of Things (IoT starts to handle high volumes of video data to facilitate multimedia-based services, which requires energy-efficient video playback. In video playback, frames have to be decoded and rendered at high playback rate, increasing the computation cost on the CPU. To save the CPU power, dynamic voltage and frequency scaling (DVFS dynamically adjusts the operating voltage of the processor along with frequency, in which appropriate selection of frequency on power could achieve a balance between performance and power. We present a decoding model that allows buffering frames to let the CPU run at low frequency and then propose an algorithm that determines the CPU frequency needed to decode each frame in a video, with the aim of minimizing power consumption while meeting buffer size and deadline constraints, using a dynamic programming technique. We finally extend this algorithm to optimize CPU frequencies over a short sequence of frames, producing a practical method of reducing the energy required for video decoding. Experimental results show a system-wide reduction in energy of 27%, compared with a processor running at full speed.

  6. Playback system designed for X-Band SAR

    International Nuclear Information System (INIS)

    Yuquan, Liu; Changyong, Dou

    2014-01-01

    SAR(Synthetic Aperture Radar) has extensive application because it is daylight and weather independent. In particular, X-Band SAR strip map, designed by Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, provides high ground resolution images, at the same time it has a large spatial coverage and a short acquisition time, so it is promising in multi-applications. When sudden disaster comes, the emergency situation acquires radar signal data and image as soon as possible, in order to take action to reduce loss and save lives in the first time. This paper summarizes a type of X-Band SAR playback processing system designed for disaster response and scientific needs. It describes SAR data workflow includes the payload data transmission and reception process. Playback processing system completes signal analysis on the original data, providing SAR level 0 products and quick image. Gigabit network promises radar signal transmission efficiency from recorder to calculation unit. Multi-thread parallel computing and ping pong operation can ensure computation speed. Through gigabit network, multi-thread parallel computing and ping pong operation, high speed data transmission and processing meet the SAR radar data playback real time requirement

  7. Playback system designed for X-Band SAR

    Science.gov (United States)

    Yuquan, Liu; Changyong, Dou

    2014-03-01

    SAR(Synthetic Aperture Radar) has extensive application because it is daylight and weather independent. In particular, X-Band SAR strip map, designed by Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, provides high ground resolution images, at the same time it has a large spatial coverage and a short acquisition time, so it is promising in multi-applications. When sudden disaster comes, the emergency situation acquires radar signal data and image as soon as possible, in order to take action to reduce loss and save lives in the first time. This paper summarizes a type of X-Band SAR playback processing system designed for disaster response and scientific needs. It describes SAR data workflow includes the payload data transmission and reception process. Playback processing system completes signal analysis on the original data, providing SAR level 0 products and quick image. Gigabit network promises radar signal transmission efficiency from recorder to calculation unit. Multi-thread parallel computing and ping pong operation can ensure computation speed. Through gigabit network, multi-thread parallel computing and ping pong operation, high speed data transmission and processing meet the SAR radar data playback real time requirement.

  8. A Study on the Development of Playback Control Software for Mark5B VSI System

    Directory of Open Access Journals (Sweden)

    S. J. Oh

    2010-06-01

    Full Text Available We developed the playback control software for a high-speed playback system which is a component of the Korea-Japan Joint VLBI Correlator (KJJVC. The Mark5B system, which is a recorder and playback system used in the Korean VLBI Network (KVN, has two kinds of operation mode. That is to say, the station unit (SU mode, which is for the present Mark4 system, and the VSI mode, which is for the new VLBI standard interface (VSI system. The software for SU is already developed and widely used in the Mark4 type VLBI system, but the software for VSI has only been developed for recording. The new VLBI system is designed with a VSI interface for compatibility between different systems. Therefore, the playback control software development of the VSI mode is needed for KVN. In this work, we developed the playback control software of the Mark5B VSI mode. The developed playback control software consists of an application part for data playing back, a data input/output part for the VSI board, a module for the StreamStor RAID board, and a user interface part, including an observation time control part. To verify the performance of developed playback control software, the playback and correlation experiments were performed using the real observation data in Mark5B system and KJJVC. To check the observation time control, the data playback experiment was performed between the Mark5B and Raw VLBI Data Buffer (RVDB systems. Through the experimental results, we confirmed the performance of developed playback control software in the Mark5B VSI mode.

  9. Female harbor seal (Phoca vitulina) behavioral response to playbacks of underwater male acoustic advertisement displays.

    Science.gov (United States)

    Matthews, Leanna P; Blades, Brittany; Parks, Susan E

    2018-01-01

    During the breeding season, male harbor seals ( Phoca vitulina ) make underwater acoustic displays using vocalizations known as roars. These roars have been shown to function in territory establishment in some breeding areas and have been hypothesized to be important for female choice, but the function of these sounds remains unresolved. This study consisted of a series of playback experiments in which captive female harbor seals were exposed to recordings of male roars to determine if females respond to recordings of male vocalizations and whether or not they respond differently to roars from categories with different acoustic characteristics. The categories included roars with characteristics of dominant males (longest duration, lowest frequency), subordinate males (shortest duration, highest frequency), combinations of call parameters from dominant and subordinate males (long duration, high frequency and short duration, low frequency), and control playbacks of water noise and water noise with tonal signals in the same frequency range as male signals. Results indicate that overall females have a significantly higher level of response to playbacks that imitate male vocalizations when compared to control playbacks of water noise. Specifically, there was a higher level of response to playbacks representing dominant male vocalization when compared to the control playbacks. For most individuals, there was a greater response to playbacks representing dominant male vocalizations compared to playbacks representing subordinate male vocalizations; however, there was no statistical difference between those two playback types. Additionally, there was no difference between the playbacks of call parameter combinations and the controls. Investigating female preference for male harbor seal vocalizations is a critical step in understanding the harbor seal mating system and further studies expanding on this captive study will help shed light on this important issue.

  10. Automated interactive video playback for studies of animal communication.

    Science.gov (United States)

    Butkowski, Trisha; Yan, Wei; Gray, Aaron M; Cui, Rongfeng; Verzijden, Machteld N; Rosenthal, Gil G

    2011-02-09

    Video playback is a widely-used technique for the controlled manipulation and presentation of visual signals in animal communication. In particular, parameter-based computer animation offers the opportunity to independently manipulate any number of behavioral, morphological, or spectral characteristics in the context of realistic, moving images of animals on screen. A major limitation of conventional playback, however, is that the visual stimulus lacks the ability to interact with the live animal. Borrowing from video-game technology, we have created an automated, interactive system for video playback that controls animations in response to real-time signals from a video tracking system. We demonstrated this method by conducting mate-choice trials on female swordtail fish, Xiphophorus birchmanni. Females were given a simultaneous choice between a courting male conspecific and a courting male heterospecific (X. malinche) on opposite sides of an aquarium. The virtual male stimulus was programmed to track the horizontal position of the female, as courting males do in the wild. Mate-choice trials on wild-caught X. birchmanni females were used to validate the prototype's ability to effectively generate a realistic visual stimulus.

  11. Evaluation of a mixed-order planar and periphonic Ambisonics playback implementation

    DEFF Research Database (Denmark)

    Käsbach, Johannes; Favrot, Sylvain Emmanuel; Buchholz, Jörg

    2011-01-01

    . In order to combine the benefits of 2D and 3D systems, a higher order 2D playback system can be mixed with a lower order 3D system. In the present study, a mixed-order Ambisonics playback system was realised by extending the spherical harmonics decomposition of a 3D sound field with additional horizontal......Planar (2D) and periphonic (3D) higher-order Ambisonics (HOA) playback systems are widely used in multi-channel audio applications. For a given Ambisonics order, 2D systems require far less loudspeakers and provide a larger spatial resolution but cannot naturally reproduce elevated sound sources...... components. The performance of the system was analysed by considering a small and a large loudspeaker setup, allowing for different combinations of 2D and 3D Ambisonics orders. An objective evaluation showed that the systems provided a high spatial resolution for horizontal sources while producing a smooth...

  12. Lion, ungulate, and visitor reactions to playbacks of lion roars at Zoo Atlanta.

    Science.gov (United States)

    Kelling, Angela S; Allard, Stephanie M; Kelling, Nicholas J; Sandhaus, Estelle A; Maple, Terry L

    2012-01-01

    Felids in captivity are often inactive and elusive in zoos, leading to a frustrating visitor experience. Eight roars were recorded from an adult male lion and played back over speakers as auditory enrichment to benefit the lions while simultaneously enhancing the zoo visitor experience. In addition, ungulates in an adjacent exhibit were observed to ensure that the novel location and increased frequency of roars did not lead to a stress or fear response. The male lion in this study roared more in the playback phase than in the baseline phases while not increasing any behaviors that would indicate compromised welfare. In addition, zoo visitors remained at the lion exhibit longer during playback. The nearby ungulates never exhibited any reactions stronger than orienting to playbacks, identical to their reactions to live roars. Therefore, naturalistic playbacks of lion roars are a potential form of auditory enrichment that leads to more instances of live lion roars and enhances the visitor experience without increasing the stress levels of nearby ungulates or the lion themselves, who might interpret the roar as that of an intruder.

  13. You talkin' to me? Interactive playback is a powerful yet underused tool in animal communication research.

    Science.gov (United States)

    King, Stephanie L

    2015-07-01

    Over the years, playback experiments have helped further our understanding of the wonderful world of animal communication. They have provided fundamental insights into animal behaviour and the function of communicative signals in numerous taxa. As important as these experiments are, however, there is strong evidence to suggest that the information conveyed in a signal may only have value when presented interactively. By their very nature, signalling exchanges are interactive and therefore, an interactive playback design is a powerful tool for examining the function of such exchanges. While researchers working on frog and songbird vocal interactions have long championed interactive playback, it remains surprisingly underused across other taxa. The interactive playback approach is not limited to studies of acoustic signalling, but can be applied to other sensory modalities, including visual, chemical and electrical communication. Here, I discuss interactive playback as a potent yet underused technique in the field of animal behaviour. I present a concise review of studies that have used interactive playback thus far, describe how it can be applied, and discuss its limitations and challenges. My hope is that this review will result in more scientists applying this innovative technique to their own study subjects, as a means of furthering our understanding of the function of signalling interactions in animal communication systems. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  14. Anthropogenic noise playback impairs embryonic development and increases mortality in a marine invertebrate

    Science.gov (United States)

    Nedelec, Sophie L.; Radford, Andrew N.; Simpson, Stephen D.; Nedelec, Brendan; Lecchini, David; Mills, Suzanne C.

    2014-07-01

    Human activities can create noise pollution and there is increasing international concern about how this may impact wildlife. There is evidence that anthropogenic noise may have detrimental effects on behaviour and physiology in many species but there are few examples of experiments showing how fitness may be directly affected. Here we use a split-brood, counterbalanced, field experiment to investigate the effect of repeated boat-noise playback during early life on the development and survival of a marine invertebrate, the sea hare Stylocheilus striatus at Moorea Island (French Polynesia). We found that exposure to boat-noise playback, compared to ambient-noise playback, reduced successful development of embryos by 21% and additionally increased mortality of recently hatched larvae by 22%. Our work, on an understudied but ecologically and socio-economically important taxon, demonstrates that anthropogenic noise can affect individual fitness. Fitness costs early in life have a fundamental influence on population dynamics and resilience, with potential implications for community structure and function.

  15. Design of digital voice storage and playback system

    Science.gov (United States)

    Tang, Chao

    2018-03-01

    Based on STC89C52 chip, this paper presents a single chip microcomputer minimum system, which is used to realize the logic control of digital speech storage and playback system. Compared with the traditional tape voice recording system, the system has advantages of small size, low power consumption, The effective solution of traditional voice recording system is limited in the use of electronic and information processing.

  16. Parallels between playbacks and Pleistocene tar seeps suggest sociality in an extinct sabretooth cat, Smilodon

    OpenAIRE

    Carbone, Chris; Maddox, Tom; Funston, Paul J.; Mills, Michael G.L.; Grether, Gregory F.; Van Valkenburgh, Blaire

    2008-01-01

    Inferences concerning the lives of extinct animals are difficult to obtain from the fossil record. Here we present a novel approach to the study of extinct carnivores, using a comparison between fossil records (n=3324) found in Late Pleistocene tar seeps at Rancho La Brea in North America and counts (n=4491) from playback experiments used to estimate carnivore abundance in Africa. Playbacks and tar seep deposits represent competitive, potentially dangerous encounters where multiple predators ...

  17. Acceleration recorder and playback module

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1994-11-01

    The present invention is directed to methods and apparatus relating to an accelerometer electrical signal recorder and playback module. The recorder module may be manufactured in lightweight configuration and includes analog memory components to store data. Signal conditioning circuitry is incorporated into the module so that signals may be connected directly from the accelerometer to the recorder module. A battery pack may be included for powering both the module and the accelerometer. Timing circuitry is included to control the time duration within which data is recorded or played back so as to avoid overloading the analog memory components. Multiple accelerometer signal recordings may be taken simultaneously without analog to digital circuits, multiplexing circuitry or software to compensate for the effects of multiplexing the signals.

  18. Message Brokering Evaluation for Live Spacecraft Telemetry Monitoring, Recorded Playback, and Analysis

    Science.gov (United States)

    Lee, Daren; Pomerantz, Marc

    2015-01-01

    Live monitoring and post-flight analysis of telemetry data play a vital role in the development, diagnosis, and deployment of components of a space flight mission. Requirements for such a system include low end-to-end latency between data producers and visualizers, preserved ordering of messages, data stream archiving with random access playback, and real-time creation of derived data streams. We evaluate the RabbitMQ and Kafka message brokering systems, on how well they can enable a real-time, scalable, and robust telemetry framework that delivers telemetry data to multiple clients across heterogeneous platforms and flight projects. In our experiments using an actively developed robotic arm testbed, Kafka yielded a much higher message throughput rate and a consistent publishing rate across the number of topics and consumers. Consumer message rates were consistent across the number of topics but can exhibit bursty behavior with an increase in the contention for a single topic partition with increasing number of consumers.

  19. Capture and playback synchronization in video conferencing

    Science.gov (United States)

    Shae, Zon-Yin; Chang, Pao-Chi; Chen, Mon-Song

    1995-03-01

    Packet-switching based video conferencing has emerged as one of the most important multimedia applications. Lip synchronization can be disrupted in the packet network as the result of the network properties: packet delay jitters at the capture end, network delay jitters, packet loss, packet arrived out of sequence, local clock mismatch, and video playback overlay with the graphic system. The synchronization problem become more demanding as the real time and multiparty requirement of the video conferencing application. Some of the above mentioned problem can be solved in the more advanced network architecture as ATM having promised. This paper will present some of the solutions to the problems that can be useful at the end station terminals in the massively deployed packet switching network today. The playback scheme in the end station will consist of two units: compression domain buffer management unit and the pixel domain buffer management unit. The pixel domain buffer management unit is responsible for removing the annoying frame shearing effect in the display. The compression domain buffer management unit is responsible for parsing the incoming packets for identifying the complete data blocks in the compressed data stream which can be decoded independently. The compression domain buffer management unit is also responsible for concealing the effects of clock mismatch, lip synchronization, and packet loss, out of sequence, and network jitters. This scheme can also be applied to the multiparty teleconferencing environment. Some of the schemes presented in this paper have been implemented in the Multiparty Multimedia Teleconferencing (MMT) system prototype at the IBM watson research center.

  20. Efficiency of playback for assessing the occurrence of five bird species in Brazilian Atlantic Forest fragments

    Directory of Open Access Journals (Sweden)

    Danilo Boscolo

    2006-12-01

    Full Text Available Playback of bird songs is a useful technique for species detection; however, this method is usually not standardized. We tested playback efficiency for five Atlantic Forest birds (White-browed Warbler Basileuterus leucoblepharus, Giant Antshrike Batara cinerea, Swallow-tailed Manakin Chiroxiphia caudata, Whiteshouldered Fire-eye Pyriglena leucoptera and Surucua Trogon Trogon surrucura for different time of the day, season of the year and species abundance at the Morro Grande Forest Reserve (South-eastern Brazil and at thirteen forest fragments in a nearby landscape. Vocalizations were broadcasted monthly at sunrise, noon and sunset, during one year. For B. leucoblepharus, C. caudata and T. surrucura, sunrise and noon were more efficient than sunset. Batara cinerea presented higher efficiency from July to October. Playback expanded the favourable period for avifaunal surveys in tropical forest, usually restricted to early morning in the breeding season. The playback was efficient in detecting the presence of all species when the abundance was not too low. But only B. leucoblepharus and T. surrucura showed abundance values significantly related to this efficiency. The present study provided a precise indication of the best daily and seasonal periods and a confidence interval to maximize the efficiency of playback to detect the occurrence of these forest species.A técnica de play-back é muito útil para a detecção de aves, mas este método geralmente não é padronizado. Sua eficiência em atestar a ocorrência de cinco espécies de aves da Mata Atlântica (Pula-pula-assobiador Basileuterus leucoblepharus, Batará Batara cinerea, Tangará Chiroxiphia caudata, Olho-de-fogo Pyriglena leucoptera e Surucuá-de-barriga-vermelha Trogon surrucura foi analisada de acordo com o horário do dia, estação do ano e abundância das espécies na Reserva Florestal do Morro Grande (São Paulo, Brasil e em treze fragmentos florestais de uma paisagem adjacente

  1. Variable-Rate Premiums

    Data.gov (United States)

    Pension Benefit Guaranty Corporation — These interest rates are used to value vested benefits for variable rate premium purposes as described in PBGC's regulation on Premium Rates (29 CFR Part 4006) and...

  2. Behavioral responses by Icelandic White-Beaked Dolphins (Lagenorhynchus albirostris) to playback sounds

    DEFF Research Database (Denmark)

    Rasmussen, Marianne H.; Atem, Ana; Miller, Lee A.

    2016-01-01

    AbstractThe aim of this study was to investigate how wild white-beaked dolphins (Lagenorhynchus albirostris)respond to the playback of novel, anthropogenic sounds. We used amplitude-modulated tones and synthetic pulse-bursts. (Some authors in the literature use the term “burst pulse” meaning a bu...... a response and a change in the natural behavior of a marine mammal—in this case, wild white-beaked dolphins........ The estimated received levels for tonal signals were from 110 to 160 dB and for pulse-bursts were 153 to 166 dB re 1 μPa (peak-to-peak). Playback of a file with no signal served as a no sound control in all experiments. The animals responded to all acoustic signals with nine different behavioral responses: (1......) circling the array, (2) turning around and approaching the camera, (3)underwater tail slapping, (4)emitting bubbles, (5)turning their belly towards the set-up, (6) emitting pulse-bursts towards the loudspeaker, (7) an increase in swim speed, (8) a change in swim direction, and (9) jumping. A total of 157...

  3. Heart rate variability in healthy population

    International Nuclear Information System (INIS)

    Alamgir, M.; Hussain, M.M.

    2010-01-01

    Background: Heart rate variability has been considered as an indicator of autonomic status. Little work has been done on heart rate variability in normal healthy volunteers. We aimed at evolving the reference values of heart rate variability in our healthy population. Methods: Twenty-four hour holter monitoring of 37 healthy individuals was done using Holter ECG recorder 'Life card CF' from 'Reynolds Medical'. Heart rate variability in both time and frequency domains was analysed with 'Reynolds Medical Pathfinder Digital/700'. Results: The heart rate variability in normal healthy volunteers of our population was found in time domain using standard deviation of R-R intervals (SDNN), standard deviation of average NN intervals (SDANN), and Square root of the mean squared differences of successive NN intervals (RMSSD). Variation in heart rate variability indices was observed between local and foreign volunteers and RMSSD was found significantly increased (p<0.05) in local population. Conclusions: The values of heart rate variability (RMSSD) in healthy Pakistani volunteers were found increased compared to the foreign data reflecting parasympathetic dominance in our population. (author)

  4. Long-time storage of song types in birds: evidence from interactive playbacks.

    Science.gov (United States)

    Geberzahn, Nicole; Hultsch, Henrike

    2003-05-22

    In studies of birdsong learning, imitation-based assays of stimulus memorization do not take into account that tutored song types may have been stored, but were not retrieved from memory. Such a 'silent' reservoir of song material could be used later in the bird's life, e.g. during vocal interactions. We examined this possibility in hand-reared nightingales during their second year. The males had been exposed to songs, both as fledglings and later, during their first full song period in an interactive playback design. Our design allowed us to compare the performance of imitations from the following categories: (i) songs only experienced during the early tutoring; (ii) songs experienced both during early tutoring and interactive playbacks; and (iii) novel songs experienced only during the simulated interactions. In their second year, birds imitated song types from each category, including those from categories (i) and (ii) which they had failed to imitate before. In addition, the performance of these song types was different (category (ii) > category (i)) and more pronounced than for category (iii) songs. Our results demonstrate 'silent' song storage in nightingales and point to a graded influence of the time and the social context of experience on subsequent vocal imitation.

  5. The importance of recording and playback technique for assessment of annoyance

    DEFF Research Database (Denmark)

    Celik, Emine; Persson Waye, Kerstin; Møller, Henrik

    2005-01-01

    in perception related to annoyance, loudness and unpleasantness between monophonic recordings played back through a loudspeaker and binaural recordings played back via headphones and to evaluate whether a possible difference depends on temporal and frequency characteristics as well as spatial characteristics...... a loudspeaker and the binaural recordings were presented through both closed (circum-aural) and completely open (free of the ear) headphones. The results show that for all judgments (annoyance, loudness and unpleasantness), there was no significant main effect of recording and playback techniques; however...

  6. Flight trajectory recreation and playback system of aerial mission based on ossimplanet

    OpenAIRE

    Wu, Wu; Hu, Jiulin; Huang, Xiaofang; Chen, Huijie; Sun, Bo

    2014-01-01

    Recreation of flight trajectory is important among research areas. The design of a flight trajectory recreation and playback system is presented in this paper. Rather than transferring the flight data to diagram, graph and table, flight data is visualized on the 3D global of ossimPlanet. ossimPlanet is an open-source 3D global geo-spatial viewer and the system realization is based on analysis it. Users are allowed to choose their interested flight of aerial mission. The aerial ...

  7. Achievable data rate in spectrum-sharing channels with variable-rate variable-power primary users

    KAUST Repository

    Yang, Yuli; Aï ssa, Sonia

    2012-01-01

    In this work, we propose a transmission strategy for secondary users (SUs) within a cognitive radio network where primary users (PUs) exploit variable-rate variable-power modulation. By monitoring the PU's transmissions, the SU adjusts its transmit

  8. Evaluating the underlying factors behind variable rate debt.

    Science.gov (United States)

    McCue, Michael J; Kim, Tae Hyun Tanny

    2007-01-01

    Recent trends show a greater usage of variable rate debt among health care bond issues. In 2004, 63.4% of the total health care bonds issued were variable rate compared with 30.6% in 1995 (Fitch Ratings, 2005). The purpose of this study is to gain a better understanding of the underlying factors, credit spread, issue characteristics, and issuer factors behind why hospitals and health system borrowers select variable rate debt compared with fixed rate debt. From 2000 to 2004, this study sampled 230 newly issued tax-exempt bonds issued by acute care hospitals and health care systems that included both variable and fixed rate debt issues. Using a logistic regression model, hospitals with variable rate debt issues were assigned a value of 1, whereas hospitals with fixed rate debt issues were assigned a value of 0. This study found a positive association between bond insurance and variable rate debt and a negative association between callable feature and variable rate debt. Facilities located in certificate-of-need states that possessed higher case mix acuity, earned higher profit margins, generated higher debt service coverage, and held less debt were more likely to issue variable rate debt. Overall, hospital managers and board members of hospitals possessing a strong financial performance have an interest in utilizing variable rate debt to lower their cost of capital. In addition, this outcome may also reflect that investment bankers are doing a better job in educating senior hospital management about the interest rate savings benefit of variable rate compared with fixed rate debt.

  9. Assessment of annoyance, loudness and unpleasantness with different recording and playback techniques

    DEFF Research Database (Denmark)

    Celik, Emine; Persson Waye, Kerstin; Møller, Henrik

    2005-01-01

    if there is a difference in perception related to annoyance, loudness and unpleasantness between monophonic recordings played back through a loudspeaker and binaural recordings played back via headphones and to evaluate whether a possible difference depends on temporal and frequency characteristics as well as spatial...... through a loudspeaker and the binaural recordings were presented through both closed (circum-aural) and completely open (free of the ear) headphones. The results show that for all judgments (annoyance, loudness and unpleasantness), there was no significant main effect of recording and playback techniques...

  10. Effects of Playback Theatre on cognitive function and quality of life in older adults in Singapore: A preliminary study.

    Science.gov (United States)

    Chung, Krystal Shu Yi; Lee, Eleena Shi Lynn; Tan, Jia Qi; Teo, Dylan Jin Hao; Lee, Chris Ban Loong; Ee, Sharifah Rose; Sim, Sam Kim Yang; Chee, Chew Sim

    2018-03-01

    This study investigated the effects of Playback Theatre on older adults' cognitive function and well-being, specifically in the Singapore context. Eighteen healthy older adults, older than 50 years of age, participated in the study. Due to practical limitations, a single-group pre-post study design was adopted. Participants completed the outcome measures before and after the training program. There were six weekly sessions in total (about 1.5 hours, once weekly). Participants experienced a significant improvement in their emotional well-being after training. However, there were no significant changes in participants' cognitive function or health-related quality of life. Our results suggest that Playback Theatre as a community program has potential to improve the mental and emotional well-being of older people. © 2018 AJA Inc.

  11. GammaLog Playback 1.0 - mobile gamma ray spectrometry software

    International Nuclear Information System (INIS)

    Watson, R.J.; Smethurst, M.A.

    2011-01-01

    The Geological Survey of Norway (NGU) operates a mobile gamma ray spectrometer system which can be used in nuclear emergency situations to determine the location and type of orphan sources, or the extent and type of fallout contamination. The system consists of a 20 litre (16 litre downward and 4 litre upward looking) RSX-5 NaI detector and spectrometer, and can be mounted in fixed wing aircraft, helicopters, or vans/cars as appropriate. NGU has developed its own data acquisition and analysis software for this system. GammaLog (Smethurst 2005) controls the acquisition, display, and storage of data from the spectrometer, and performs real-time data analysis including estimation of dose rates and fallout concentrations, and separation of geological and anthropogenic components of the signal. The latter is particularly important where the geological radioisotope signal varies strongly from one place to another, and makes it easier to locate and identify anthropogenic sources which might otherwise be difficult to separate from the geological background signal. A modified version of GammaLog has been developed, GammaLog Playback, which allows the replay of previously acquired GammaLog datasets, while performing similar processing and display as the GammaLog acquisition software. This allows datasets to be reviewed and compared in the field or during post-survey analysis to help plan subsequent measurement strategies.(Au)

  12. Speed control variable rate irrigation

    Science.gov (United States)

    Speed control variable rate irrigation (VRI) is used to address within field variability by controlling a moving sprinkler’s travel speed to vary the application depth. Changes in speed are commonly practiced over areas that slope, pond or where soil texture is predominantly different. Dynamic presc...

  13. 7 CFR 1735.33 - Variable interest rate loans.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Variable interest rate loans. 1735.33 Section 1735.33... § 1735.33 Variable interest rate loans. After June 10, 1991, and prior to November 1, 1993, RUS made certain variable rate loans at interest rates less than 5 percent but not less than 2 percent. For those...

  14. 12 CFR 619.9340 - Variable interest rate.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Variable interest rate. 619.9340 Section 619.9340 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM DEFINITIONS § 619.9340 Variable interest rate. An interest rate on the outstanding loan balances, which may be changed from time to time...

  15. Response-rate differences in variable-interval and variable-ratio schedules: An old problem revisited

    OpenAIRE

    Cole, Mark R.

    1994-01-01

    In Experiment 1, a variable-ratio 10 schedule became, successively, a variable-interval schedule with only the minimum interreinforcement intervals yoked to the variable ratio, or a variable-interval schedule with both interreinforcement intervals and reinforced interresponse times yoked to the variable ratio. Response rates in the variable-interval schedule with both interreinforcement interval and reinforced interresponse time yoking fell between the higher rates maintained by the variable-...

  16. Heart Rate Variability - A Historical Perspective

    Directory of Open Access Journals (Sweden)

    George E Billman

    2011-11-01

    Full Text Available Heart rate variability (HRV, the beat-to-beat variation in either heart rate or the duration of the R-R interval – the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration – the so called respiratory sinus arrhythmia, RSA and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contributions of the parasympathetic and the sympathetic divisions of the autonomic nervous system to this variability are controversial and remain the subject of active investigation and debate, a number of time and frequency domain techniques have been developed to provide insight into cardiac autonomic regulation in both health and disease. It is the purpose of this essay to provide an historical overview of the evolution in the concept of heart rate variability. Briefly, pulse rate was first measured by ancient Greek physicians and scientists. However, it was not until the invention of the Physician’s Pulse Watch (a watch with a second hand that could be stopped in 1707 that changes in pulse rate could be accurately assessed. The Rev. Stephen Hales (1733 was the first to note that pulse varied with respiration and in 1847 Carl Ludwig was the first to record RSA. With the measurement of the ECG (1895 and advent of digital signal processing techniques in the 1960’s, investigation of HRV and its relationship to health and disease has exploded. This essay will conclude with a brief description of time domain, frequency domain, and non-linear dynamic analysis techniques (and their limitations that are commonly used to measure heart rate variability.

  17. Heart rate variability interventions for concussion and rehabilitation

    OpenAIRE

    Conder, Robert L.; Conder, Alanna A.

    2014-01-01

    The study of Heart Rate Variability (HRV) has emerged as an essential component of cardiovascular health, as well as a physiological mechanism by which one can increase the interactive communication between the cardiac and the neurocognitive systems (i.e., the body and the brain). It is well-established that lack of heart rate variability implies cardiopathology, morbidity, reduced quality-of-life, and precipitous mortality. On the positive, optimal heart rate variability has been associated ...

  18. Assessment of variable application rates of biological amendment ...

    African Journals Online (AJOL)

    Assessment of variable application rates of biological amendment substances on establishment and growth characteristics of maize plants. ... Hence, a greenhouse experiment was conducted in 2008 to assess the effects of variable rates (50, 75 and 100% of the recommended rates) of industrial manufactured biological ...

  19. [Resonance hypothesis of heart rate variability origin].

    Science.gov (United States)

    Sheĭkh-Zade, Iu R; Mukhambetaliev, G Kh; Cherednik, I L

    2009-09-01

    A hypothesis is advanced of the heart rate variability being subjected to beat-to-beat regulation of cardiac cycle duration in order to ensure the resonance interaction between respiratory and own fluctuation of the arterial system volume for minimization of power expenses of cardiorespiratory system. Myogenic, parasympathetic and sympathetic machanisms of heart rate variability are described.

  20. An efficient HW and SW design of H.264 video compression, storage and playback on FPGA devices for handheld thermal imaging systems

    Science.gov (United States)

    Gunay, Omer; Ozsarac, Ismail; Kamisli, Fatih

    2017-05-01

    Video recording is an essential property of new generation military imaging systems. Playback of the stored video on the same device is also desirable as it provides several operational benefits to end users. Two very important constraints for many military imaging systems, especially for hand-held devices and thermal weapon sights, are power consumption and size. To meet these constraints, it is essential to perform most of the processing applied to the video signal, such as preprocessing, compression, storing, decoding, playback and other system functions on a single programmable chip, such as FPGA, DSP, GPU or ASIC. In this work, H.264/AVC (Advanced Video Coding) compatible video compression, storage, decoding and playback blocks are efficiently designed and implemented on FPGA platforms using FPGA fabric and Altera NIOS II soft processor. Many subblocks that are used in video encoding are also used during video decoding in order to save FPGA resources and power. Computationally complex blocks are designed using FPGA fabric, while blocks such as SD card write/read, H.264 syntax decoding and CAVLC decoding are done using NIOS processor to benefit from software flexibility. In addition, to keep power consumption low, the system was designed to require limited external memory access. The design was tested using 640x480 25 fps thermal camera on CYCLONE V FPGA, which is the ALTERA's lowest power FPGA family, and consumes lower than 40% of CYCLONE V 5CEFA7 FPGA resources on average.

  1. Quality-Based Backlight Optimization for Video Playback on Handheld Devices

    Directory of Open Access Journals (Sweden)

    Liang Cheng

    2007-01-01

    Full Text Available For a typical handheld device, the backlight accounts for a significant percentage of the total energy consumption (e.g., around 30% for a Compaq iPAQ 3650. Substantial energy savings can be achieved by dynamically adapting backlight intensity levels on such low-power portable devices. In this paper, we analyze the characteristics of video streaming services and propose a cross-layer optimization scheme called quality adapted backlight scaling (QABS to achieve backlight energy savings for video playback applications on handheld devices. Specifically, we present a fast algorithm to optimize backlight dimming while keeping the degradation in image quality to a minimum so that the overall service quality is close to a specified threshold. Additionally, we propose two effective techniques to prevent frequent backlight switching, which negatively affects user perception of video. Our initial experimental results indicate that the energy used for backlight is significantly reduced, while the desired quality is satisfied. The proposed algorithms can be realized in real time.

  2. Changes in heart rate variability and QT variability during the first trimester of pregnancy.

    Science.gov (United States)

    Carpenter, R E; D'Silva, L A; Emery, S J; Uzun, O; Rassi, D; Lewis, M J

    2015-03-01

    The risk of new-onset arrhythmia during pregnancy is high, presumably relating to changes in both haemodynamic and cardiac autonomic function. The ability to non-invasively assess an individual's risk of developing arrhythmia during pregnancy would therefore be clinically significant. We aimed to quantify electrocardiographic temporal characteristics during the first trimester of pregnancy and to compare these with non-pregnant controls. Ninety-nine pregnant women and sixty-three non-pregnant women underwent non-invasive cardiovascular and haemodynamic assessment during a protocol consisting of various physiological states (postural manoeurvres, light exercise and metronomic breathing). Variables measured included stroke volume, cardiac output, heart rate, heart rate variability, QT and QT variability and QTVI (a measure of the variability of QT relative to that of RR). Heart rate (p pregnancy only during the supine position (p pregnancy in all physiological states (p pregnancy in all states (p pregnancy is associated with substantial changes in heart rate variability, reflecting a reduction in parasympathetic tone and an increase in sympathetic activity. QTVI shifted to a less favourable value, reflecting a greater than normal amount of QT variability. QTVI appears to be a useful method for quantifying changes in QT variability relative to RR (or heart rate) variability, being sensitive not only to physiological state but also to gestational age. We support the use of non-invasive markers of cardiac electrical variability to evaluate the risk of arrhythmic events in pregnancy, and we recommend the use of multiple physiological states during the assessment protocol.

  3. Effects of Liraglutide on Heart Rate and Heart Rate Variability

    DEFF Research Database (Denmark)

    Kumarathurai, Preman; Anholm, Christian; Larsen, Bjørn Strøier

    2017-01-01

    OBJECTIVE: Reduced heart rate variability (HRV) and increased heart rate (HR) have been associated with cardiovascular mortality. Glucagon-like peptide 1 receptor agonists (GLP-1 RAs) increase HR, and studies have suggested that they may reduce HRV. We examined the effect of the GLP-1 RA...

  4. Achievable data rate in spectrum-sharing channels with variable-rate variable-power primary users

    KAUST Repository

    Yang, Yuli

    2012-08-01

    In this work, we propose a transmission strategy for secondary users (SUs) within a cognitive radio network where primary users (PUs) exploit variable-rate variable-power modulation. By monitoring the PU\\'s transmissions, the SU adjusts its transmit power based on the gap between the PU\\'s received effective signal-to-noise power ratio (SNR) and the lower SNR boundary for the modulation mode that is being used in the primary link. Thus, at the SU\\'s presence, the PU\\'s quality of service (QoS) is guaranteed without increasing its processing complexity thanks to no interference cancellation required in the PU\\'s operation. To demonstrate the advantage of our proposed transmission strategy, we analyze the secondary user\\'s achievable data rate by taking into account different transmission capabilities for the secondary transmitter. The corresponding numerical results not only prove the validity of our derivations but also provide a convenient tool for the network design with the proposed transmission strategy. © 2012 IEEE.

  5. High-Rate Communications Outage Recorder Operations for Optimal Payload and Science Telemetry Management Onboard the International Space Station

    Science.gov (United States)

    Shell, Michael T.; McElyea, Richard M. (Technical Monitor)

    2002-01-01

    All International Space Station (ISS) Ku-band telemetry transmits through the High-Rate Communications Outage Recorder (HCOR). The HCOR provides the recording and playback capability for all payload, science, and International Partner data streams transmitting through NASA's Ku-band antenna system. The HCOR is a solid-state memory recorder that provides recording capability to record all eight ISS high-rate data during ISS Loss-of-Signal periods. NASA payloads in the Destiny module are prime users of the HCOR; however, NASDA and ESA will also utilize the HCOR for data capture and playback of their high data rate links from the Kibo and Columbus modules. Marshall Space Flight Center's Payload Operations Integration Center manages the HCOR for nominal functions, including system configurations and playback operations. The purpose of this paper is to present the nominal operations plan for the HCOR and the plans for handling contingency operations affecting payload operations. In addition, the paper will address HCOR operation limitations and the expected effects on payload operations. The HCOR is manifested for ISS delivery on flight 9A with the HCOR backup manifested on flight 11A. The HCOR replaces the Medium-Rate Communications Outage Recorder (MCOR), which has supported payloads since flight 5A.1.

  6. Responses to playback of different subspecies songs in the Reed Bunting (Emberiza s. schoeniclus)

    DEFF Research Database (Denmark)

    Matessi, Giuliano; Dabelsteen, Torben; Pilastro, A.

    2000-01-01

    Populations of Reed Buntings Emberiza schoeniclus in the western Palearctic are classified in two major subspecies groups according to morphology: northern migratory schoeniclus and Mediterranean resident intermedia. Songs of the two groups differ mainly in complexity and syllable structure......, with intermedia songs being more complex. We explored the possibilities of song as a subspecies isolating mechanism by testing if male schoeniclus Reed Buntings reacted differently to field playbacks of songs from their own subspecies group, from the foreign subspecies group and from a control species...

  7. Risks and rewards of variable-rate debt.

    Science.gov (United States)

    Jordahl, Eric A

    2012-05-01

    Hospital and health system finance leaders should position their organizations to participate in the variable-rate market. To this end, one important step is to establish the right baseline variable-rate exposure target for the organization based on its credit and risk profile. Leaders also should be thoroughly familiar with the available products and understand the circumstances (pricing, terms, and embedded risk) under which the organization would be willing to deploy them within the overall capital structure.

  8. Zone edge effects with variable rate irrigation

    Science.gov (United States)

    Variable rate irrigation (VRI) systems may offer solutions to enhance water use efficiency by addressing variability within a field. However, the design of VRI systems should be considered to maximize application uniformity within sprinkler zones, while minimizing edge effects between such zones alo...

  9. Heart rate variability in newborns.

    Science.gov (United States)

    Javorka, K; Lehotska, Z; Kozar, M; Uhrikova, Z; Kolarovszki, B; Javorka, M; Zibolen, M

    2017-09-22

    Heart rate (HR) and heart rate variability (HRV) in newborns is influenced by genetic determinants, gestational and postnatal age, and other variables. Premature infants have a reduced HRV. In neonatal HRV evaluated by spectral analysis, a dominant activity can be found in low frequency (LF) band (combined parasympathetic and sympathetic component). During the first postnatal days the activity in the high frequency (HF) band (parasympathetic component) rises, together with an increase in LF band and total HRV. Hypotrophy in newborn can cause less mature autonomic cardiac control with a higher contribution of sympathetic activity to HRV as demonstrated by sequence plot analysis. During quiet sleep (QS) in newborns HF oscillations increase - a phenomenon less expressed or missing in premature infants. In active sleep (AS), HRV is enhanced in contrast to reduced activity in HF band due to the rise of spectral activity in LF band. Comparison of the HR and HRV in newborns born by physiological vaginal delivery, without (VD) and with epidural anesthesia (EDA) and via sectio cesarea (SC) showed no significant differences in HR and in HRV time domain parameters. Analysis in the frequency domain revealed, that the lowest sympathetic activity in chronotropic cardiac chronotropic regulation is in the VD group. Different neonatal pathological states can be associated with a reduction of HRV and an improvement in the health conditions is followed by changes in HRV what can be use as a possible prognostic marker. Examination of heart rate variability in neonatology can provide information on the maturity of the cardiac chronotropic regulation in early postnatal life, on postnatal adaptation and in pathological conditions about the potential dysregulation of cardiac function in newborns, especially in preterm infants.

  10. Notes on some experiments on the application of subtractive compensation to USGS seismic magnetic tape recording and playback systems

    Science.gov (United States)

    Eaton, Jerry P.

    1975-01-01

    The purpose of these experiments is to lay the groundwork for the implementation of subtractive compensation of the USGS seismic network tape playbacks utilizing the Develco model 6203 discriminators at a x1 playback speed. Although the Develco discriminators were designed for this application and a matching Develco compensation discriminator was purchased, effective use of this system for subtractive compensation has been blocked by the inadequate (frequency dependent) matching of the phase of the compensation signal to that of the data signal at the point compensation is carried out in the data discriminators. John Van Schaack has ameliorated the phase mismatch problem by an empirical alteration of the compensation discriminator input bandpass filter. We have selected a set (of eight) Develco discriminators and adjusted their compensation signal input levels to minimize spurious signals (noise) originating from tape speed irregularities. The sensitivity of the data discriminators was adjusted so that deviations of +125 Hz and -125 Hz produced output signals of +2.00 volts and -2.00 volts, respectively. The eight data discriminators are driven by a multiplex signal on a single tape track (subcarriers 680, 1020, 1360, 1700, 2040, 2380, 2720, and 3060 Hz). The Develco-supplied compensation discriminator requires an unmodulated 3125 Hz signal on a separate tape track.

  11. Duet function in the yellow-naped amazon, Amazona auropalliata: evidence from playbacks of duets and solos.

    Science.gov (United States)

    Dahlin, Christine R; Wright, Timothy F

    2012-01-01

    The question of why animals participate in duets is an intriguing one, as many such displays appear to be more costly to produce than individual signals. Mated pairs of yellow-naped amazons, Amazona auropalliata, give duets on their nesting territories. We investigated the function of those duets with a playback experiment. We tested two hypotheses for the function of those duets: the joint territory defense hypothesis and the mate-guarding hypothesis, by presenting territorial pairs with three types of playback treatments: duets, male solos, and female solos. The joint territory defense hypothesis suggests that individuals engage in duets because they appear more threatening than solos and are thus more effective for the establishment, maintenance and/or defense of territories. It predicts that pairs will be coordinated in their response (pair members approach speakers and vocalize together) and will either respond more strongly (more calls and/or more movement) to duet treatments than to solo treatments, or respond equally to all treatments. Alternatively, the mate-guarding hypothesis suggests that individuals participate in duets because they allow them to acoustically guard their mate, and predicts uncoordinated responses by pairs, with weak responses to duet treatments and stronger responses by individuals to solos produced by the same sex. Yellow-naped amazon pairs responded to all treatments in an equivalently aggressive and coordinated manner by rapidly approaching speakers and vocalizing more. These responses generally support the joint territory defense hypothesis and further suggest that all intruders are viewed as a threat by resident pairs.

  12. The roles of vocal and visual interactions in social learning zebra finches: A video playback experiment.

    Science.gov (United States)

    Guillette, Lauren M; Healy, Susan D

    2017-06-01

    The transmission of information from an experienced demonstrator to a naïve observer often depends on characteristics of the demonstrator, such as familiarity, success or dominance status. Whether or not the demonstrator pays attention to and/or interacts with the observer may also affect social information acquisition or use by the observer. Here we used a video-demonstrator paradigm first to test whether video demonstrators have the same effect as using live demonstrators in zebra finches, and second, to test the importance of visual and vocal interactions between the demonstrator and observer on social information use by the observer. We found that female zebra finches copied novel food choices of male demonstrators they saw via live-streaming video while they did not consistently copy from the demonstrators when they were seen in playbacks of the same videos. Although naive observers copied in the absence of vocalizations by the demonstrator, as they copied from playback of videos with the sound off, females did not copy where there was a mis-match between the visual information provided by the video and vocal information from a live male that was out of sight. Taken together these results suggest that video demonstration is a useful methodology for testing social information transfer, at least in a foraging context, but more importantly, that social information use varies according to the vocal interactions, or lack thereof, between the observer and the demonstrator. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  13. Exchange rate variability, market activity and heterogeneity

    OpenAIRE

    Rime, Dagfinn; Sucarrat, Genaro

    2007-01-01

    We study the role played by geographic and bank-size heterogeneity in the relation between exchange rate variability and market activity. We find some support for the hypothesis that increases in short-term global interbank market activity, which can be interpreted as due to variation in information arrival, increase variability. However, our results do not suggest that local short-term activity increases variability. With respect to long-term market activity, which can be interpreted as a me...

  14. Heart rate variability in bipolar disorder

    DEFF Research Database (Denmark)

    Faurholt-Jepsen, Maria; Kessing, Lars Vedel; Munkholm, Klaus

    2017-01-01

    Background Heart rate variability (HRV) has been suggested reduced in bipolar disorder (BD) compared with healthy individuals (HC). This meta-analysis investigated: HRV differences in BD compared with HC, major depressive disorder or schizophrenia; HRV differences between affective states; HRV...

  15. Entropies, Partitionings and Heart Rate Variability

    Czech Academy of Sciences Publication Activity Database

    Paluš, Milan; Zebrowski, J.

    2009-01-01

    Roč. 51, č. 2 (2009), s. 65-72 ISSN 0001-7604 Institutional research plan: CEZ:AV0Z10300504 Keywords : coarse-grained entropy rate * HR variability * entropy Subject RIV: BB - Applied Statistics, Operational Research http://www.activitas.org/index.php/nervosa/article/view/25

  16. Heart Rate Variability Interventions for Concussion and Rehabilitation

    Directory of Open Access Journals (Sweden)

    Robert Lake Conder

    2014-08-01

    Full Text Available The study of Heart Rate Variability (HRV has emerged as an essential component of cardiovascular health, as well as a physiological mechanism by which one can increase the interactive communication between the cardiac and the neurocognitive systems (i.e., the body and the brain. It is well-established that lack of heart rate variability implies cardiopathology, morbidity, reduced quality-of-life, and precipitous mortality. On the positive, optimal heart rate variability has been associated with good cardiovascular health, autonomic nervous system (ANS control, emotional regulation, and enhanced neurocognitive processing. In addition to health benefits, optimal HRV has been shown to improve neurocognitive performance by enhancing focus, visual acuity and readiness, and by promoting emotional regulation needed for peak performance. In concussed athletes and soldiers, concussions not only alter brain connectivity, but also alter cardiac functioning and impair cardiovascular performance upon exertion. Altered sympathetic and parasympathetic balance in the ANS has been postulated as a critical factor in refractory Post Concussive Syndrome (PCS. This article will review both the pathological aspects of reduced heart rate variability on athletic performance, as well as the cardiovascular and cerebrovascular components of concussion and PCS. Additionally, this article will review interventions with HRV biofeedback (HRV BFB training as a promising and underutilized treatment for sports and military-related concussion. Finally, this article will review research and promising case studies pertaining to use of HRV BFB for enhancement of cognition and performance, with applicability to concussion rehabilitation.

  17. 13 CFR 120.214 - What conditions apply for variable interest rates?

    Science.gov (United States)

    2010-01-01

    ... interest rates? 120.214 Section 120.214 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Policies Specific to 7(a) Loans Maturities; Interest Rates; Loan and Guarantee Amounts § 120.214 What conditions apply for variable interest rates? A Lender may use a variable rate of interest...

  18. Enabling MPEG-2 video playback in embedded systems through improved data cache efficiency

    Science.gov (United States)

    Soderquist, Peter; Leeser, Miriam E.

    1999-01-01

    Digital video decoding, enabled by the MPEG-2 Video standard, is an important future application for embedded systems, particularly PDAs and other information appliances. Many such system require portability and wireless communication capabilities, and thus face severe limitations in size and power consumption. This places a premium on integration and efficiency, and favors software solutions for video functionality over specialized hardware. The processors in most embedded system currently lack the computational power needed to perform video decoding, but a related and equally important problem is the required data bandwidth, and the need to cost-effectively insure adequate data supply. MPEG data sets are very large, and generate significant amounts of excess memory traffic for standard data caches, up to 100 times the amount required for decoding. Meanwhile, cost and power limitations restrict cache sizes in embedded systems. Some systems, including many media processors, eliminate caches in favor of memories under direct, painstaking software control in the manner of digital signal processors. Yet MPEG data has locality which caches can exploit if properly optimized, providing fast, flexible, and automatic data supply. We propose a set of enhancements which target the specific needs of the heterogeneous types within the MPEG decoder working set. These optimizations significantly improve the efficiency of small caches, reducing cache-memory traffic by almost 70 percent, and can make an enhanced 4 KB cache perform better than a standard 1 MB cache. This performance improvement can enable high-resolution, full frame rate video playback in cheaper, smaller system than woudl otherwise be possible.

  19. OBSERVER RATING VERSUS THREE-DIMENSIONAL MOTION ANALYSIS OF LOWER EXTREMITY KINEMATICS DURING FUNCTIONAL SCREENING TESTS: A SYSTEMATIC REVIEW.

    Science.gov (United States)

    Maclachlan, Liam; White, Steven G; Reid, Duncan

    2015-08-01

    the results of those assessing running and side-step cutting manoeuvres. Variables such as the speed of movement, the methods of rating, the profiles of participants and the experience levels of observers may have influenced the outcomes of functional testing. The small number of studies used limits generalizability. Furthermore, this review used two dimensional video-playback for the majority of observations. If the movements had been rated in real-time three dimensional video, the results may have been different. Slower, speed controlled movements using dichotomous ratings reach target sensitivity and demonstrate higher overall levels of agreement. As a result, their utilization in functional screening is advocated. 1A.

  20. Transforming variability to profitability – variable seed rates in New Zealand maize

    OpenAIRE

    Holmes, A

    2017-01-01

    The use of variable rate seeding (VRS) in arable crops to match seeding rates to areas with homogenous paddock performance, known as Management Zones (MZ) is widespread worldwide. However, VRS has not been undertaken in commercial maize crops in New Zealand. This paper outlines a single maize VRS trial carried out in the 2015/16 growing season in the Waikato, New Zealand, to investigate the relationship between different seeding rates and MZ to maximise crop yield, but also gross margin (GM)....

  1. Heart rate variability and baroreflex sensitivity in bilateral lung transplant recipients.

    Science.gov (United States)

    Fontolliet, Timothée; Gianella, Pietro; Pichot, Vincent; Barthélémy, Jean-Claude; Gasche-Soccal, Paola; Ferretti, Guido; Lador, Frédéric

    2018-01-09

    The effects of lung afferents denervation on cardiovascular regulation can be assessed on bilateral lung transplantation patients. The high-frequency component of heart rate variability is known to be synchronous with breathing frequency. Then, if heart beat is neurally modulated by breathing frequency, we may expect disappearance of high frequency of heart rate variability in bilateral lung transplantation patients. On 11 patients and 11 matching healthy controls, we measured R-R interval (electrocardiography), blood pressure (Portapres ® ) and breathing frequency (ultrasonic device) in supine rest, during 10-min free breathing, 10-min cadenced breathing (0·25 Hz) and 5-min handgrip. We analysed heart rate variability and spontaneous variability of arterial blood pressure, by power spectral analysis, and baroreflex sensitivity, by the sequence method. Concerning heart rate variability, with respect to controls, transplant recipients had lower total power and lower low- and high-frequency power. The low-frequency/high-frequency ratio was higher. Concerning systolic, diastolic and mean arterial pressure variability, transplant recipients had lower total power (only for cadenced breathing), low frequency and low-frequency/high-frequency ratio during free and cadenced breathing. Baroreflex sensitivity was decreased. Denervated lungs induced strong heart rate variability reduction. The higher low-frequency/high-frequency ratio suggested that the total power drop was mostly due to high frequency. These results support the hypothesis that neural modulation from lung afferents contributes to the high frequency of heart rate variability. © 2018 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  2. The Extent of Variability of Rates of Building Items in Botswana ...

    African Journals Online (AJOL)

    This paper reports findings of a study carried out to investigate the variability of rates of common building items used in public building projects in Botswana. The paper concludes that tiling and glazing were found to have the highest rate of variability, while reinforcement and masonry had the lowest price variability.

  3. Heart rate variability - a historical perspective.

    Science.gov (United States)

    Billman, George E

    2011-01-01

    Heart rate variability (HRV), the beat-to-beat variation in either heart rate or the duration of the R-R interval - the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration - the so called respiratory sinus arrhythmia, RSA) and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contributions of the parasympathetic and the sympathetic divisions of the autonomic nervous system to this variability are controversial and remain the subject of active investigation and debate, a number of time and frequency domain techniques have been developed to provide insight into cardiac autonomic regulation in both health and disease. It is the purpose of this essay to provide an historical overview of the evolution in the concept of HRV. Briefly, pulse rate was first measured by ancient Greek physicians and scientists. However, it was not until the invention of the "Physician's Pulse Watch" (a watch with a second hand that could be stopped) in 1707 that changes in pulse rate could be accurately assessed. The Rev. Stephen Hales (1733) was the first to note that pulse varied with respiration and in 1847 Carl Ludwig was the first to record RSA. With the measurement of the ECG (1895) and advent of digital signal processing techniques in the 1960s, investigation of HRV and its relationship to health and disease has exploded. This essay will conclude with a brief description of time domain, frequency domain, and non-linear dynamic analysis techniques (and their limitations) that are commonly used to measure HRV.

  4. Sigh rate and respiratory variability during mental load and sustained attention.

    Science.gov (United States)

    Vlemincx, Elke; Taelman, Joachim; De Peuter, Steven; Van Diest, Ilse; Van den Bergh, Omer

    2011-01-01

    Spontaneous breathing consists of substantial correlated variability: Parameters characterizing a breath are correlated with parameters characterizing previous and future breaths. On the basis of dynamic system theory, negative emotion states are predicted to reduce correlated variability whereas sustained attention is expected to reduce total respiratory variability. Both are predicted to evoke sighing. To test this, respiratory variability and sighing were assessed during a baseline, stressful mental arithmetic task, nonstressful sustained attention task, and recovery in between tasks. For respiration rate (excluding sighs), reduced total variability was found during the attention task, whereas correlated variation was reduced during mental load. Sigh rate increased during mental load and during recovery from the attention task. It is concluded that mental load and task-related attention show specific patterns in respiratory variability and sigh rate. Copyright © 2010 Society for Psychophysiological Research.

  5. Two-Stage Variable Sample-Rate Conversion System

    Science.gov (United States)

    Tkacenko, Andre

    2009-01-01

    A two-stage variable sample-rate conversion (SRC) system has been pro posed as part of a digital signal-processing system in a digital com munication radio receiver that utilizes a variety of data rates. The proposed system would be used as an interface between (1) an analog- todigital converter used in the front end of the receiver to sample an intermediatefrequency signal at a fixed input rate and (2) digita lly implemented tracking loops in subsequent stages that operate at v arious sample rates that are generally lower than the input sample r ate. This Two-Stage System would be capable of converting from an input sample rate to a desired lower output sample rate that could be var iable and not necessarily a rational fraction of the input rate.

  6. Female song rates in response to simulated intruder are positively related to reproductive success.

    Directory of Open Access Journals (Sweden)

    Kristal E Cain

    2015-10-01

    Full Text Available Bird song is well studied in males as a sexually selected behavior. However, although song is also common among females, it is infrequently examined and poorly understood. Research suggests that song is often used as a resource defense behavior and is important in female-female competition for limited resources, e.g. mates and territories. If so, song should be positively related to fitness and related to other resource defense behaviors, but this possibility has rarely been explored. Here we examine fitness estimates in relation to spontaneous song rates and song rates in response to a simulated intruder (playback, in the superb fairy-wren (Malurus cyaneus, a cooperatively breeding songbird. We also determine how song rates relate to other territorial defense behaviors. Song rate in response to playback, but not spontaneous song rate, was positively related to nest success and the number of fledglings produced by successful females. Further, response song rate was also correlated with other territorial defense behaviors (latency to respond and flights. This evidence supports the hypothesis that female song may be used in the context of female-female competition to improve access to limited reproductive resources, and suggests that song may provide direct fitness benefits.

  7. Real Exchange Rate Variability: An Empirical Analysis of the Developing Countries Case

    OpenAIRE

    Sebastian Edwards

    1986-01-01

    The purpose of this paper is to investigate the potential role of monetary and real factors in explaining real exchange rate variability in developing countries. For this purpose two indexes of real effective exchange rate variability that measure short-term and long-term variability were constructed for 30 countries. The results obtained, using a generalized least squares procedures on cross section data, indicate that real exchange rate variability has been affected both by real and monetar...

  8. Variable dose rate single-arc IMAT delivered with a constant dose rate and variable angular spacing

    International Nuclear Information System (INIS)

    Tang, Grace; Earl, Matthew A; Yu, Cedric X

    2009-01-01

    Single-arc intensity-modulated arc therapy (IMAT) has gained worldwide interest in both research and clinical implementation due to its superior plan quality and delivery efficiency. Single-arc IMAT techniques such as the Varian RapidArc(TM) deliver conformal dose distributions to the target in one single gantry rotation, resulting in a delivery time in the order of 2 min. The segments in these techniques are evenly distributed within an arc and are allowed to have different monitor unit (MU) weightings. Therefore, a variable dose-rate (VDR) is required for delivery. Because the VDR requirement complicates the control hardware and software of the linear accelerators (linacs) and prevents most existing linacs from delivering IMAT, we propose an alternative planning approach for IMAT using constant dose-rate (CDR) delivery with variable angular spacing. We prove the equivalence by converting VDR-optimized RapidArc plans to CDR plans, where the evenly spaced beams in the VDR plan are redistributed to uneven spacing such that the segments with larger MU weighting occupy a greater angular interval. To minimize perturbation in the optimized dose distribution, the angular deviation of the segments was restricted to ≤± 5 deg. This restriction requires the treatment arc to be broken into multiple sectors such that the local MU fluctuation within each sector is reduced, thereby lowering the angular deviation of the segments during redistribution. The converted CDR plans were delivered with a single gantry sweep as in the VDR plans but each sector was delivered with a different value of CDR. For four patient cases, including two head-and-neck, one brain and one prostate, all CDR plans developed with the variable spacing scheme produced similar dose distributions to the original VDR plans. For plans with complex angular MU distributions, the number of sectors increased up to four in the CDR plans in order to maintain the original plan quality. Since each sector was

  9. Variable exhumation rates and variable displacement rates: Documenting recent slowing of Himalayan shortening in western Bhutan

    Science.gov (United States)

    McQuarrie, Nadine; Tobgay, Tobgay; Long, Sean P.; Reiners, Peter W.; Cosca, Michael A.

    2014-01-01

    We link exhumational variability in space and time to the evolving geometry of the Himalayan fold–thrust belt in western Bhutan. By combining new and published geochronologic and thermochronologic data we document the burial age, peak temperatures and complete cooling history from 20 Ma to the present over an across-strike distance of ∼125 km. These integrated cooling curves highlight windows of fast exhumation that vary spatially and temporally. We propose that pulses of fast exhumation are a result of structures that facilitate the vertical motion of material, illustrated in sequentially-restored cross sections. Due to a range of permissible geometries at depth, we explore and evaluate the impact of geometry on kinematics and rates of deformation. The linked cooling history and cross sections provide estimates of both magnitude and timing of thrust sheet displacement and highlight temporal variability in potential shortening rates. Structural and chronologic data illustrate a general north to south progression of Himalayan deformation, with emplacement of the Main Central thrust (MCT), Paro thrust and Shumar thrust by 12 to no later than 9 Ma. Two different geometries and kinematic scenarios for the Lesser Himalayan duplex are proposed. A north to south propagating duplex system requires that the southern portion of that system, south of the MCT, deformed and cooled by 9 Ma, leaving only the southernmost thrust sheets, including the Main Boundary and Main Frontal thrusts, to deform between 9 and 0 Ma. This limited post 9 Ma shortening would necessitate a marked slowdown in convergence accommodated on the Main Himalayan thrust. A two-tiered duplex system, which allows for the Paro window duplex and the southern Baxa duplex to form simultaneously, permits duplex formation and accompanying exhumation until 6 Ma. Limited cooling from ∼200 °C to the surface post 6 Ma suggests either a decrease in shortening rates from 6 to 0 Ma or that duplex formation and

  10. Gaussian Mixture Model of Heart Rate Variability

    Science.gov (United States)

    Costa, Tommaso; Boccignone, Giuseppe; Ferraro, Mario

    2012-01-01

    Heart rate variability (HRV) is an important measure of sympathetic and parasympathetic functions of the autonomic nervous system and a key indicator of cardiovascular condition. This paper proposes a novel method to investigate HRV, namely by modelling it as a linear combination of Gaussians. Results show that three Gaussians are enough to describe the stationary statistics of heart variability and to provide a straightforward interpretation of the HRV power spectrum. Comparisons have been made also with synthetic data generated from different physiologically based models showing the plausibility of the Gaussian mixture parameters. PMID:22666386

  11. Increased heart rate variability but normal resting metabolic rate in hypocretin/orexin-deficient human narcolepsy.

    NARCIS (Netherlands)

    Fronczek, R.; Overeem, S.; Reijntjes, R.; Lammers, G.J.; Dijk, J.G.M.; Pijl, H.

    2008-01-01

    STUDY OBJECTIVES: We investigated autonomic balance and resting metabolic rate to explore their possible involvement in obesity in hypocretin/orexin-deficient narcoleptic subjects. METHODS: Resting metabolic rate (using indirect calorimetry) and variability in heart rate and blood pressure were

  12. An application of the variable-r method to subpopulation growth rates in a 19th century agricultural population

    Directory of Open Access Journals (Sweden)

    Corey Sparks

    2009-07-01

    Full Text Available This paper presents an analysis of the differential growth rates of the farming and non-farming segments of a rural Scottish community during the 19th and early 20th centuries using the variable-r method allowing for net migration. Using this method, I find that the farming population of Orkney, Scotland, showed less variability in their reproduction and growth rates than the non-farming population during a period of net population decline. I conclude by suggesting that the variable-r method can be used in general cases where the relative growth of subpopulations or subpopulation reproduction is of interest.

  13. Variability in case-mix adjusted in-hospital cardiac arrest rates.

    Science.gov (United States)

    Merchant, Raina M; Yang, Lin; Becker, Lance B; Berg, Robert A; Nadkarni, Vinay; Nichol, Graham; Carr, Brendan G; Mitra, Nandita; Bradley, Steven M; Abella, Benjamin S; Groeneveld, Peter W

    2012-02-01

    It is unknown how in-hospital cardiac arrest (IHCA) rates vary across hospitals and predictors of variability. Measure variability in IHCA across hospitals and determine if hospital-level factors predict differences in case-mix adjusted event rates. Get with the Guidelines Resuscitation (GWTG-R) (n=433 hospitals) was used to identify IHCA events between 2003 and 2007. The American Hospital Association survey, Medicare, and US Census were used to obtain detailed information about GWTG-R hospitals. Adult patients with IHCA. Case-mix-adjusted predicted IHCA rates were calculated for each hospital and variability across hospitals was compared. A regression model was used to predict case-mix adjusted event rates using hospital measures of volume, nurse-to-bed ratio, percent intensive care unit beds, palliative care services, urban designation, volume of black patients, income, trauma designation, academic designation, cardiac surgery capability, and a patient risk score. We evaluated 103,117 adult IHCAs at 433 US hospitals. The case-mix adjusted IHCA event rate was highly variable across hospitals, median 1/1000 bed days (interquartile range: 0.7 to 1.3 events/1000 bed days). In a multivariable regression model, case-mix adjusted IHCA event rates were highest in urban hospitals [rate ratio (RR), 1.1; 95% confidence interval (CI), 1.0-1.3; P=0.03] and hospitals with higher proportions of black patients (RR, 1.2; 95% CI, 1.0-1.3; P=0.01) and lower in larger hospitals (RR, 0.54; 95% CI, 0.45-0.66; PCase-mix adjusted IHCA event rates varied considerably across hospitals. Several hospital factors associated with higher IHCA event rates were consistent with factors often linked with lower hospital quality of care.

  14. Variables That Can Affect Student Ratings of Their Professors

    Science.gov (United States)

    Gotlieb, Jerry

    2013-01-01

    Attribution theory was applied to help predict the results of an experiment that examined the effects of three independent variables on students' ratings of their professors. The dependent variables were students' perceptions of whether the professor caused the students' grades and student satisfaction with their professor. The results suggest…

  15. Approximate entropy and point correlation dimension of heart rate variability in healthy subjects

    DEFF Research Database (Denmark)

    Storella, R J; Wood, H W; Mills, K M

    1999-01-01

    The contribution of nonlinear dynamics to heart rate variability in healthy humans was examined using surrogate data analysis. Several measures of heart rate variability were used and compared. Heart rates were recorded for three hours and original data sets of 8192 R-R intervals created. For each...... original data set (n = 34), three surrogate data sets were made by shuffling the order of the R-R intervals while retaining their linear correlations. The difference in heart rate variability between the original and surrogate data sets reflects the amount of nonlinear structure in the original data set....... Heart rate variability was analyzed by two different nonlinear methods, point correlation dimension and approximate entropy. Nonlinearity, though under 10 percent, could be detected with both types of heart rate variability measures. More importantly, not only were the correlations between...

  16. Digital signal processor for silicon audio playback devices; Silicon audio saisei kikiyo digital signal processor

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    The digital audio signal processor (DSP) TC9446F series has been developed silicon audio playback devices with a memory medium of, e.g., flash memory, DVD players, and AV devices, e.g., TV sets. It corresponds to AAC (advanced audio coding) (2ch) and MP3 (MPEG1 Layer3), as the audio compressing techniques being used for transmitting music through an internet. It also corresponds to compressed types, e.g., Dolby Digital, DTS (digital theater system) and MPEG2 audio, being adopted for, e.g., DVDs. It can carry a built-in audio signal processing program, e.g., Dolby ProLogic, equalizer, sound field controlling, and 3D sound. TC9446XB has been lined up anew. It adopts an FBGA (fine pitch ball grid array) package for portable audio devices. (translated by NEDO)

  17. Effects of social stress on heart rate and heart rate variability in growing pigs

    NARCIS (Netherlands)

    Jong, de I.C.; Sgoifo, A.; Lambooij, E.; Korte, S.M.; Blokhuis, H.J.; Koolhaas, J.M.

    2000-01-01

    The effects of social stress on heart rate, heart rate variability and the occurrence of cardiac arrhythmias were studied in 12 growing pigs. Social stress was induced during a good competition test with a pen mate, and subsequently during a resident-intruder test with an unacquainted pig in which

  18. Effects of social stress on heart rate and heart rate variability in growing pigs

    NARCIS (Netherlands)

    de Jong, IC; Sgoifo, A; Lambooij, E; Korte, SM; Blokhuis, HJ; Koolhaas, JM

    The effects of social stress on heart rate, heart rate variability and the occurrence of cardiac arrhythmias were studied in 12 growing pigs. Social stress was induced during a good competition test with a pen mate, and subsequently during a resident-intruder test with an unacquainted pig in which

  19. Using video playbacks to study visual communication in a marine fish, Salaria pavo.

    Science.gov (United States)

    Gonçalves; Oliveira; Körner; Poschadel; Schlupp

    2000-09-01

    Video playbacks have been successfully applied to the study of visual communication in several groups of animals. However, this technique is controversial as video monitors are designed with the human visual system in mind. Differences between the visual capabilities of humans and other animals will lead to perceptually different interpretations of video images. We simultaneously presented males and females of the peacock blenny, Salaria pavo, with a live conspecific male and an online video image of the same individual. Video images failed to elicit appropriate responses. Males were aggressive towards the live male but not towards video images of the same male. Similarly, females courted only the live male and spent more time near this stimulus. In contrast, females of the gynogenetic poecilid Poecilia formosa showed an equal preference for a live and video image of a P. mexicana male, suggesting a response to live animals as strong as to video images. We discuss differences between the species that may explain their opposite reaction to video images. Copyright 2000 The Association for the Study of Animal Behaviour.

  20. Use efficiency of variable rate of nitrogen prescribed by optical sensor in corn

    Directory of Open Access Journals (Sweden)

    Jardes Bragagnolo

    2016-02-01

    Full Text Available ABSTRACT The efficiency of nitrogen fertilizer in corn is usually low, negatively affecting plant nutrition, the economic return, and the environment. In this context, a variable rate of nitrogen, prescribed by crop sensors, has been proposed as an alternative to the uniform rate of nitrogen traditionally used by farmers. This study tested the hypothesis that variable rate of nitrogen, prescribed by optical sensor, increases the nitrogen use efficiency and grain yield as compared to uniform rate of nitrogen. The following treatments were evaluated: 0; 70; 140; and 210 kg ha-1 under uniform rate of nitrogen, and 140 kg ha -1 under variable rate of nitrogen. The nitrogen source was urea applied on the soil surface using a distributor equipped with the crop sensor. In this study, the grain yield ranged from 10.2 to 15.5 Mg ha-1, with linear response to nitrogen rates. The variable rate of nitrogen increased by 11.8 and 32.6% the nitrogen uptake and nitrogen use efficiency, respectively, compared to the uniform rate of nitrogen. However, no significant increase in grain yield was observed, indicating that the major benefit of the variable rate of nitrogen was reducing the risk of environmental impact of fertilizer.

  1. Short- and long-term variations in non-linear dynamics of heart rate variability

    DEFF Research Database (Denmark)

    Kanters, J K; Højgaard, M V; Agner, E

    1996-01-01

    OBJECTIVES: The purpose of the study was to investigate the short- and long-term variations in the non-linear dynamics of heart rate variability, and to determine the relationships between conventional time and frequency domain methods and the newer non-linear methods of characterizing heart rate...... rate and describes mainly linear correlations. Non-linear predictability is correlated with heart rate variability measured as the standard deviation of the R-R intervals and the respiratory activity expressed as power of the high-frequency band. The dynamics of heart rate variability changes suddenly...

  2. Heart rate variability in normal-weight patients with polycystic ovary syndrome.

    Science.gov (United States)

    Kilit, Celal; Paşalı Kilit, Türkan

    2017-05-01

    Polycystic ovary syndrome (PCOS) is an endocrine disease closely related to several risk factors of cardiovascular disease. Obese women with PCOS show altered autonomic modulation. The results of studies investigating cardiac autonomic functions of normal-weight women with PCOS are conflicting. The aim of the study was to assess the reactivity of cardiac sympathovagal balance in normal-weight women with PCOS by heart rate variability analysis. We examined the heart rate variability in 60 normal-weight women with PCOS and compared them with that in 60 age-matched healthy women having a similar metabolic profile. Time and frequency domain parameters of heart rate variability were analyzed based on 5-min-long continuous electrocardiography recordings for the following 3 periods: (1) during rest in supine position, (2) during controlled breathing, and (3) during isometric handgrip exercise. Time and frequency domain parameters of heart rate variability for the 3 periods assessed were similar in the two groups. Although modified Ferriman-Gallwey score and serum testosterone and luteinizing hormone levels were significantly higher in women with PCOS, homeostatic model assessment-insulin resistance (HOMA-IR) was not different the between the PCOS and control groups. There were no significant correlations between serum testosterone levels and heart rate variability parameters among the study population. The findings of this study suggest that the reactivity of cardiac sympathovagal balance is not altered in normal-weight women with PCOS having a normal HOMA-IR.

  3. Associations between bolus infusion of hydrocortisone, glycemic variability and insulin infusion rate variability in critically Ill patients under moderate glycemic control

    NARCIS (Netherlands)

    van Hooijdonk, Roosmarijn T. M.; Binnekade, Jan M.; Bos, Lieuwe D. J.; Horn, Janneke; Juffermans, Nicole P.; Abu-Hanna, Ameen; Schultz, Marcus J.

    2015-01-01

    We retrospectively studied associations between bolus infusion of hydrocortisone and variability of the blood glucose level and changes in insulin rates in intensive care unit (ICU) patients. 'Glycemic variability' and 'insulin infusion rate variability' were calculated from and expressed as the

  4. Effect of atrioventricular conduction on heart rate variability

    KAUST Repository

    Ahmad, Talha Jamal; Ali, Hussnain; Majeed, S. M Imran; Khan, Shoab A.

    2011-01-01

    This paper discusses the effect of atrioventricular conduction time (AVCT) on the short-term Heart Rate Variability (HRV) by computing HRV parameters using intervals between the onsets of successive P waves (PP time series) for three groups: normal

  5. gHRV: Heart rate variability analysis made easy.

    Science.gov (United States)

    Rodríguez-Liñares, L; Lado, M J; Vila, X A; Méndez, A J; Cuesta, P

    2014-08-01

    In this paper, the gHRV software tool is presented. It is a simple, free and portable tool developed in python for analysing heart rate variability. It includes a graphical user interface and it can import files in multiple formats, analyse time intervals in the signal, test statistical significance and export the results. This paper also contains, as an example of use, a clinical analysis performed with the gHRV tool, namely to determine whether the heart rate variability indexes change across different stages of sleep. Results from tests completed by researchers who have tried gHRV are also explained: in general the application was positively valued and results reflect a high level of satisfaction. gHRV is in continuous development and new versions will include suggestions made by testers. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  6. Vigorous physical activity predicts higher heart rate variability among younger adults.

    Science.gov (United States)

    May, Richard; McBerty, Victoria; Zaky, Adam; Gianotti, Melino

    2017-06-14

    Baseline heart rate variability (HRV) is linked to prospective cardiovascular health. We tested intensity and duration of weekly physical activity as predictors of heart rate variability in young adults. Time and frequency domain indices of HRV were calculated based on 5-min resting electrocardiograms collected from 82 undergraduate students. Hours per week of both moderate and vigorous activity were estimated using the International Physical Activity Questionnaire. In regression analyses, hours of vigorous physical activity, but not moderate activity, significantly predicted greater time domain and frequency domain indices of heart rate variability. Adjusted for weekly frequency, greater daily duration of vigorous activity failed to predict HRV indices. Future studies should test direct measurements of vigorous activity patterns as predictors of autonomic function in young adulthood.

  7. iHeartLift: a closed loop system with bio-feedback that uses music tempo variability to improve heart rate variability.

    Science.gov (United States)

    Ho, Thomas C T; Chen, Xiang

    2011-01-01

    "Musica delenit bestiam feram" translates into "Music soothes the savage beast". There is a hidden truth in this ancient quip passed down from generations. Besides soothing the heart, it also incites the heart to a healthier level of heart rate variability (HRV). In this paper, an approach to use and test music and biofeedback to increase the heart rate variability for people facing daily stress is discussed. By determining the music tempo variability (MTV) of a piece of music and current heart rate variability, iHeartLift is able to compare the 2 trends and locate a musical piece that is suited to increase the user's heart rate variability to a healthier level. With biofeedback, the 2 trends are continuously compared in real-time and the musical piece is changed in accordance with the current comparisons. A study was conducted and it was generally found that HRV can be uplifted by music regardless of language and meaning of musical lyrics but with limitations to musical genre.

  8. Relationship of suicide rates with climate and economic variables in Europe during 2000-2012

    DEFF Research Database (Denmark)

    Fountoulakis, Konstantinos N; Chatzikosta, Isaia; Pastiadis, Konstantinos

    2016-01-01

    BACKGROUND: It is well known that suicidal rates vary considerably among European countries and the reasons for this are unknown, although several theories have been proposed. The effect of economic variables has been extensively studied but not that of climate. METHODS: Data from 29 European...... countries covering the years 2000-2012 and concerning male and female standardized suicidal rates (according to WHO), economic variables (according World Bank) and climate variables were gathered. The statistical analysis included cluster and principal component analysis and categorical regression. RESULTS......: The derived models explained 62.4 % of the variability of male suicidal rates. Economic variables alone explained 26.9 % and climate variables 37.6 %. For females, the respective figures were 41.7, 11.5 and 28.1 %. Male suicides correlated with high unemployment rate in the frame of high growth rate and high...

  9. Continuous measurement of heart rate variability following carbon ...

    African Journals Online (AJOL)

    Background: Previous studies of autonomic nervous system activity through analysis of heart rate variability (HRV) have demonstrated increased sympathetic activity during positive-pressure pneumoperitoneum. We employed an online, continuous method for rapid HRV analysis (MemCalc™, Tarawa, Suwa Trust, Tokyo, ...

  10. Cardiovascular Reactivity and Heart Rate Variability in Panic Disorder

    National Research Council Canada - National Science Library

    Santiago, Helen T

    1999-01-01

    .... Because previous studies of cardiovascular reactivity and heart rate variability have been inconclusive, these factors were re-examined in panickers and controls during physiological challenge...

  11. Derivation and application of hydraulic equation for variable-rate ...

    African Journals Online (AJOL)

    The variable-rate contour-controlled sprinkler (VRCS) for precision irrigation can throw water on a given shaped area and the flow rate is also varied with the throw distance of the sprinkler for the purpose of high uniformity irrigation. Much of past research work were concentrated on the mechanical availability of ...

  12. [The influence of physical exercise on heart rate variability].

    Science.gov (United States)

    Gajek, Jacek; Zyśko, Dorota; Negrusz-Kawecka, Marta; Halawa, Bogumił

    2003-03-01

    Heart rate variability is controlled by the influence of autonomic nervous system, whereas one part of the system modulates the activity of the other. There is evidence of increased sympathetic activity in patients (pts) with essential hypertension. The aim of the study was to assess the persisting influence of increased sympathetic activity 30 min after moderate physical exercise on heart rate variability in patients with arterial hypertension. The study was performed in 19 patients (10 women, mean age 52.7 +/- 9.5 years and 9 men, mean age 37.7 +/- 8.8 years) with stage I (6 pts) and stage II (13 pts) arterial hypertension. All studied pts had sinus rhythm, were free of diabetes, coronary heart disease and congestive heart failure. 24-hour Holter monitoring was performed and for 30 min before the exercise test the pts stayed in supine rest. The exercise tests were performed between 10 and 11 a.m. Immediately after the exercise all pts stayed in supine position for 30 min. The heart rate variability parameters were studied using Holter monitoring system Medilog Optima Jet and were then analysed statistically. The mean energy expenditure during the exercise was 5.8 +/- 1.1 METs and the maximal heart rate was 148.1 +/- 20.3 bpm. All studied HRV parameters were significantly different in the assessed time period compared to the baseline values (p < 0.001). Significant correlation was found between the age of the studied patients and the mean RR interval, what can be considered as a hyperkinetic (hyperadrenergic) circulatory status and shorter RR interval in younger pts. Significant negative correlation between the age and SDNN parameter (r = -0.65, p < 0.001), 30 min after the exercise mirrors the prolonged adrenergic influence in older pts. The present study shows that the influence of moderate physical exercise on heart rate variability in pts with essential hypertension is extended over 30 min period after exercise and is more pronounced in older pts. The studies

  13. Gender differences of heart rate variability in healthy volunteers

    International Nuclear Information System (INIS)

    Saleem, S.; Majeed, S.M.I.; Khan, M.A.

    2012-01-01

    Objective: To identify the basic values of heart rate variability in Pakistani population and to verify our hypothesis that there are gender differences in cardiovascular autonomic modulation. Methods: The descriptive cross sectional study based on convenience probability sampling was conducted at Armed Forces Institute of Cardiology/National Institute of Heart Diseases (AFIC/NIHD) Pakistan. The duration of the study was from December 2009 to July 2010. It involved 24-hour holter monitoring of 45 healthy individuals using holter electrocardiography (ECG) recorder. Heart rate variability was analysed in time (SDNN, SDANN, SDNNi, rMSSD, pNN50) and frequency domains (power, VLF, LF, and HF). Results: The time domain indices; SDNN (male=140 +- 36 ms vs. females=122 +- 33 ms; p =0.09), SDANN (male=123 +- 34 ms vs. females=111+- 34 ms; P= 0.23), SDNNi (male=64 +-19 ms vs. females=52 +- 14 ms; P= 0.03), and pNN50 (male=14 +- 10 ms vs. females=12 +- 7 ms; P= 0.43) were decreased in female volunteers when compared with males. Comparison of frequency domain indices; Total power (male=4041 +- 3150 ms/sup 2/ vs. females=2750 +- 1439 ms/sup 2/; P= 0.07), VLF (male=291 2675 ms/sup 2/ vs. females=1843 +- 928 ms/sup 2/; P= 0.06), LF (male=788 +- 397 ms/sup 2/ vs. females=556 +- 346 ms/sup 2/; P= 0.04) and HF (male=318 +- 251 ms/sup 2/ vs. females=31 277 ms/sup 2/; P= 0.94) amongst males and females showed attenuated heart rate variability in females. Of all the observed values, SDNNi and LF were found significantly (p <0.05) decreased in women. Conclusion: In healthy population, heart rate variability is low in women than men. It reflects sympathetic dominance in women in our population. (author)

  14. Effect of atrioventricular conduction on heart rate variability

    KAUST Repository

    Ahmad, Talha Jamal

    2011-08-01

    This paper discusses the effect of atrioventricular conduction time (AVCT) on the short-term Heart Rate Variability (HRV) by computing HRV parameters using intervals between the onsets of successive P waves (PP time series) for three groups: normal, arrhythmia and sudden cardiac death (SCD) patients. A very precise wavelet transform based ECG delineator was developed to detect PP, PR and RR time series. Mean PR variation in arrhythmia and SCD group was found to be significantly high as compared to the normal group. It was observed that when PR variations in arrhythmia and SCD cases crossed a certain threshold, RR variability no longer provided a very accurate estimate of HRV. In such cases, PP variability was able to provide a better assessment of HRV. © 2011 IEEE.

  15. Continuous measurement of heart rate variability following carbon ...

    African Journals Online (AJOL)

    2010-07-16

    Jul 16, 2010 ... Power spectral analysis of the electrocardiographic R-R interval [heart rate variability: (HRV)] is a well known, non- invasive method for assessing autonomic nervous activity.1. Studies using HRV analysis during positive-pressure pneumoperitoneum (PPP) have demonstrated increased sympathetic ...

  16. Playback Theatre as a tool to enhance communication in medical education

    Directory of Open Access Journals (Sweden)

    Ramiro Salas

    2013-12-01

    Full Text Available Playback Theatre (PT is an improvisational form of theatre in which a group of actors “play back” real life stories told by audience members. In PT, a conductor elicits moments, feelings and stories from audience members, and conducts mini-interviews with those who volunteer a moment of their lives to be re-enacted or “played” for the audience. A musician plays music according to the theme of each story, and 4-5 actors listen to the interview and perform the story that has just been told. PT has been used in a large number of settings as a tool to share stories in an artistic manner. Despite its similarities to psychodrama, PT does not claim to be a form of therapy.We offered two PT performances to first year medical students at Baylor College of Medicine in Houston, Texas, to bring the students a safe and fun environment, conducive to sharing feelings and moments related to being a medical student. Through the moments and stories shared by students, we conclude that there is an enormous need in this population for opportunities to communicate the many emotions associated with medical school and with healthcare-related personal experiences, such as anxiety, pride, or anger. PT proved a powerful tool to help students communicate.

  17. Reduced heart rate variability in social anxiety disorder: associations with gender and symptom severity.

    Directory of Open Access Journals (Sweden)

    Gail A Alvares

    Full Text Available BACKGROUND: Polyvagal theory emphasizes that autonomic nervous system functioning plays a key role in social behavior and emotion. The theory predicts that psychiatric disorders of social dysfunction are associated with reduced heart rate variability, an index of autonomic control, as well as social inhibition and avoidance. The purpose of this study was to examine whether heart rate variability was reduced in treatment-seeking patients diagnosed with social anxiety disorder, a disorder characterized by social fear and avoidance. METHODS: Social anxiety patients (n = 53 were recruited prior to receiving psychological therapy. Healthy volunteers were recruited through the University of Sydney and the general community and were matched by gender and age (n = 53. Heart rate variability was assessed during a five-minute recording at rest, with participants completing a range of self-report clinical symptom measures. RESULTS: Compared to controls, participants with social anxiety exhibited significant reductions across a number of heart rate variability measures. Reductions in heart rate variability were observed in females with social anxiety, compared to female controls, and in patients taking psychotropic medication compared to non-medicated patients. Finally, within the clinical group, we observed significant associations between reduced heart rate variability and increased social interaction anxiety, psychological distress, and harmful alcohol use. CONCLUSIONS: The results of this study confirm that social anxiety disorder is associated with reduced heart rate variability. Resting state heart rate variability may therefore be considered a marker for social approach-related motivation and capacity for social engagement. Additionally, heart rate variability may provide a useful biomarker to explain underlying difficulties with social approach, impaired stress regulation, and behavioral inhibition, especially in disorders associated with

  18. Heart rate variability in patients with systemic lupus erythematosus: a systematic review and methodological considerations.

    Science.gov (United States)

    Matusik, P S; Matusik, P T; Stein, P K

    2018-07-01

    Aim The aim of this review was to summarize current knowledge about the scientific findings and potential clinical utility of heart rate variability measures in patients with systemic lupus erythematosus. Methods PubMed, Embase and Scopus databases were searched for the terms associated with systemic lupus erythematosus and heart rate variability, including controlled vocabulary, when appropriate. Articles published in English and available in full text were considered. Finally, 11 publications were selected, according to the systematic review protocol and were analyzed. Results In general, heart rate variability, measured in the time and frequency domains, was reported to be decreased in patients with systemic lupus erythematosus compared with controls. In some systemic lupus erythematosus studies, heart rate variability was found to correlate with inflammatory markers and albumin levels. A novel heart rate variability measure, heart rate turbulence onset, was shown to be increased, while heart rate turbulence slope was decreased in systemic lupus erythematosus patients. Reports of associations of changes in heart rate variability parameters with increasing systemic lupus erythematosus activity were inconsistent, showing decreasing heart rate variability or no relationship. However, the low/high frequency ratio was, in some studies, reported to increase with increasing disease activity or to be inversely correlated with albumin levels. Conclusions Patients with systemic lupus erythematosus have abnormal heart rate variability, which reflects cardiac autonomic dysfunction and may be related to inflammatory cytokines but not necessarily to disease activity. Thus measurement of heart rate variability could be a useful clinical tool for monitoring autonomic dysfunction in systemic lupus erythematosus, and may potentially provide prognostic information.

  19. The Impact of Soil Sampling Errors on Variable Rate Fertilization

    Energy Technology Data Exchange (ETDEWEB)

    R. L. Hoskinson; R C. Rope; L G. Blackwood; R D. Lee; R K. Fink

    2004-07-01

    Variable rate fertilization of an agricultural field is done taking into account spatial variability in the soil’s characteristics. Most often, spatial variability in the soil’s fertility is the primary characteristic used to determine the differences in fertilizers applied from one point to the next. For several years the Idaho National Engineering and Environmental Laboratory (INEEL) has been developing a Decision Support System for Agriculture (DSS4Ag) to determine the economically optimum recipe of various fertilizers to apply at each site in a field, based on existing soil fertility at the site, predicted yield of the crop that would result (and a predicted harvest-time market price), and the current costs and compositions of the fertilizers to be applied. Typically, soil is sampled at selected points within a field, the soil samples are analyzed in a lab, and the lab-measured soil fertility of the point samples is used for spatial interpolation, in some statistical manner, to determine the soil fertility at all other points in the field. Then a decision tool determines the fertilizers to apply at each point. Our research was conducted to measure the impact on the variable rate fertilization recipe caused by variability in the measurement of the soil’s fertility at the sampling points. The variability could be laboratory analytical errors or errors from variation in the sample collection method. The results show that for many of the fertility parameters, laboratory measurement error variance exceeds the estimated variability of the fertility measure across grid locations. These errors resulted in DSS4Ag fertilizer recipe recommended application rates that differed by up to 138 pounds of urea per acre, with half the field differing by more than 57 pounds of urea per acre. For potash the difference in application rate was up to 895 pounds per acre and over half the field differed by more than 242 pounds of potash per acre. Urea and potash differences

  20. Infant breathing rate counter based on variable resistor for pneumonia

    Science.gov (United States)

    Sakti, Novi Angga; Hardiyanto, Ardy Dwi; La Febry Andira R., C.; Camelya, Kesa; Widiyanti, Prihartini

    2016-03-01

    Pneumonia is one of the leading causes of death in new born baby in Indonesia. According to WHO in 2002, breathing rate is very important index to be the symptom of pneumonia. In the Community Health Center, the nurses count with a stopwatch for exactly one minute. Miscalculation in Community Health Center occurs because of long time concentration and focus on two object at once. This calculation errors can cause the baby who should be admitted to the hospital only be attended at home. Therefore, an accurate breathing rate counter at Community Health Center level is necessary. In this work, resistance change of variable resistor is made to be breathing rate counter. Resistance change in voltage divider can produce voltage change. If the variable resistance moves periodically, the voltage will change periodically too. The voltage change counted by software in the microcontroller. For the every mm shift at the variable resistor produce average 0.96 voltage change. The software can count the number of wave generated by shifting resistor.

  1. Conventional heart rate variability analysis of ambulatory electrocardiographic recordings fails to predict imminent ventricular fibrillation

    Science.gov (United States)

    Vybiral, T.; Glaeser, D. H.; Goldberger, A. L.; Rigney, D. R.; Hess, K. R.; Mietus, J.; Skinner, J. E.; Francis, M.; Pratt, C. M.

    1993-01-01

    OBJECTIVES. The purpose of this report was to study heart rate variability in Holter recordings of patients who experienced ventricular fibrillation during the recording. BACKGROUND. Decreased heart rate variability is recognized as a long-term predictor of overall and arrhythmic death after myocardial infarction. It was therefore postulated that heart rate variability would be lowest when measured immediately before ventricular fibrillation. METHODS. Conventional indexes of heart rate variability were calculated from Holter recordings of 24 patients with structural heart disease who had ventricular fibrillation during monitoring. The control group consisted of 19 patients with coronary artery disease, of comparable age and left ventricular ejection fraction, who had nonsustained ventricular tachycardia but no ventricular fibrillation. RESULTS. Heart rate variability did not differ between the two groups, and no consistent trends in heart rate variability were observed before ventricular fibrillation occurred. CONCLUSIONS. Although conventional heart rate variability is an independent long-term predictor of adverse outcome after myocardial infarction, its clinical utility as a short-term predictor of life-threatening arrhythmias remains to be elucidated.

  2. Do high fetal catecholamine levels affect heart rate variability and ...

    African Journals Online (AJOL)

    Objectives. To deternrine the relationship between Umbilical arterial catecholamine levels and fetal heart rate variability and meconium passage. Study design. A prospective descriptive study was perfonned. Umbilical artery catecholamine levels were measured in 55 newborns and correlated with fetal heart rate before ...

  3. Variable selection for mixture and promotion time cure rate models.

    Science.gov (United States)

    Masud, Abdullah; Tu, Wanzhu; Yu, Zhangsheng

    2016-11-16

    Failure-time data with cured patients are common in clinical studies. Data from these studies are typically analyzed with cure rate models. Variable selection methods have not been well developed for cure rate models. In this research, we propose two least absolute shrinkage and selection operators based methods, for variable selection in mixture and promotion time cure models with parametric or nonparametric baseline hazards. We conduct an extensive simulation study to assess the operating characteristics of the proposed methods. We illustrate the use of the methods using data from a study of childhood wheezing. © The Author(s) 2016.

  4. Endogenous Pain Modulation: Association with Resting Heart Rate Variability and Negative Affectivity.

    Science.gov (United States)

    Van Den Houte, Maaike; Van Oudenhove, Lukas; Bogaerts, Katleen; Van Diest, Ilse; Van den Bergh, Omer

    2017-07-21

    Several chronic pain syndromes are characterized by deficient endogenous pain modulation as well as elevated negative affectivity and reduced resting heart rate variability. In order to elucidate the relationships between these characteristics, we investigated whether negative affectivity and heart rate variability are associated with endogenous pain modulation in a healthy population. An offset analgesia paradigm with noxious thermal stimulation calibrated to the individual's pain threshold was used to measure endogenous pain modulation magnitude in 63 healthy individuals. Pain ratings during constant noxious heat stimulation to the arm (15 seconds) were compared with ratings during noxious stimulation comprising a 1 °C rise and return of temperature to the initial level (offset trials, 15 seconds). Offset analgesia was defined as the reduction in pain following the 1 °C decrease relative to pain at the same time point during continuous heat stimulation. Evidence for an offset analgesia effect could only be found when noxious stimulation intensity (and, hence, the individual's pain threshold) was intermediate (46 °C or 47 °C). Offset analgesia magnitude was also moderated by resting heart rate variability: a small but significant offset effect was found in participants with high but not low heart rate variability. Negative affectivity was not related to offset analgesia magnitude. These results indicate that resting heart rate variability (HRV) is related to endogenous pain modulation (EPM) in a healthy population. Future research should focus on clarifying the causal relationship between HRV and EPM and chronic pain by using longitudinal study designs. © 2017 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  5. Multimedia consultation session recording and playback using Java-based browser in global PACS

    Science.gov (United States)

    Martinez, Ralph; Shah, Pinkesh J.; Yu, Yuan-Pin

    1998-07-01

    The current version of the Global PACS software system uses a Java-based implementation of the Remote Consultation and Diagnosis (RCD) system. The Java RCD includes a multimedia consultation session between physicians that includes text, static image, image annotation, and audio data. The JAVA RCD allows 2-4 physicians to collaborate on a patient case. It allows physicians to join the session via WWW Java-enabled browsers or stand alone RCD application. The RCD system includes a distributed database archive system for archiving and retrieving patient and session data. The RCD system can be used for store and forward scenarios, case reviews, and interactive RCD multimedia sessions. The RCD system operates over the Internet, telephone lines, or in a private Intranet. A multimedia consultation session can be recorded, and then played back at a later time for review, comments, and education. A session can be played back using Java-enabled WWW browsers on any operating system platform. The JAVA RCD system shows that a case diagnosis can be captured digitally and played back with the original real-time temporal relationships between data streams. In this paper, we describe design and implementation of the RCD session playback.

  6. Nationwide Macroeconomic Variables and the Growth Rate of Bariatric Surgeries in Brazil.

    Science.gov (United States)

    Cazzo, Everton; Ramos, Almino Cardoso; Pareja, José Carlos; Chaim, Elinton Adami

    2018-06-06

    The effect of nationwide economic issues on the necessary expansion in the number of bariatric procedures remains unclear. This study aims to determine whether there are correlations between the growth rate in the number of bariatric surgeries and the major macroeconomic variables over time in Brazil. It is a nationwide analysis regarding the number of bariatric surgeries in Brazil and the main national macroeconomic variables from 2003 through 2016: gross domestic product (GDP), inflation rate, and the unemployment rate, as well as the evolution in the number of registered bariatric surgeons. There were significant positive correlations of the growth rate of surgeries with the early variations of the GDP (R = 0.5558; p = 0.04863) and of the overall health expenditure per capita (R = 0.78322; p = 0.00259). The growth rate of the number of bariatric surgeries was not correlated with the unemployment and inflation rates, as well as with the growth rate of available bariatric surgeons. There were direct relationships between the growth rate of bariatric surgeries and the evolutions of the GDP and health care expenditure per capita. These variables appear to influence the nationwide offer of bariatric surgery.

  7. Heart rate variability based on risk stratification for type 2 diabetes mellitus.

    Science.gov (United States)

    Silva-E-Oliveira, Julia; Amélio, Pâmela Marina; Abranches, Isabela Lopes Laguardia; Damasceno, Dênis Derly; Furtado, Fabianne

    2017-01-01

    To evaluate heart rate variability among adults with different risk levels for type 2 diabetes mellitus. The risk for type 2 diabetes mellitus was assessed in 130 participants (89 females) based on the questionnaire Finnish Diabetes Risk Score and was classified as low risk (n=26), slightly elevated risk (n=41), moderate risk (n=27) and high risk (n=32). To measure heart rate variability, a heart-rate monitor Polar S810i® was employed to obtain RR series for each individual, at rest, for 5 minutes, followed by analysis of linear and nonlinear indexes. The groups at higher risk of type 2 diabetes mellitus had significantly lower linear and nonlinear heart rate variability indexes. The individuals at high risk for type 2 diabetes mellitus have lower heart rate variability. Avaliar a variabilidade da frequência cardíaca em adultos com diferentes níveis de risco para diabetes mellitus tipo 2. O grau de risco para diabetes mellitus tipo 2 de 130 participantes (41 homens) foi avaliado pelo questionário Finnish Diabetes Risk Score. Os participantes foram classificados em baixo risco (n=26), risco levemente elevado (n=41), risco moderado (n=27) e alto risco (n=32). Para medir a variabilidade da frequência cardíaca, utilizou-se o frequencímetro Polar S810i® para obter séries de intervalo RR para cada indivíduo, em repouso, durante 5 minutos; posteriormente, realizou-se análise por meio de índices lineares e não-lineares. O grupo com maior risco para diabetes mellitus tipo 2 teve uma diminuição significante nos índices lineares e não-lineares da variabilidade da frequência cardíaca. Os resultados apontam que indivíduos com risco alto para diabetes mellitus tipo 2 tem menor variabilidade da frequência cardíaca. To evaluate heart rate variability among adults with different risk levels for type 2 diabetes mellitus. The risk for type 2 diabetes mellitus was assessed in 130 participants (89 females) based on the questionnaire Finnish Diabetes Risk Score

  8. Separating the effect of respiration from the heart rate variability for cases of constant harmonic breathing

    Directory of Open Access Journals (Sweden)

    Kircher Michael

    2015-09-01

    Full Text Available Heart Rate Variability studies are a known measure for the autonomous control of the heart rate. In special situations, its interpretation can be ambiguous, since the respiration has a major influence on the heart rate variability. For this reason it has often been proposed to measure Heart Rate Variability, while the subjects are breathing at a constant respiration rate. That way the spectral influence of the respiration is known. In this work we propose to remove this constant respiratory influence from the heart rate and the Heart Rate Variability parameters to gain respiration free autonomous controlled heart rate signal. The spectral respiratory component in the heart rate signal is detected and characterized. Subsequently the respiratory effect on Heart Rate Variability is removed using spectral filtering approaches, such as the Notch filter or the Raised Cosine filter. As a result new decoupled Heart Variability parameters are gained, which could lead to new additional interpretations of the autonomous control of the heart rate.

  9. Ambulatory ECG and analysis of heart rate variability in Parkinson's disease.

    Science.gov (United States)

    Haapaniemi, T H; Pursiainen, V; Korpelainen, J T; Huikuri, H V; Sotaniemi, K A; Myllylä, V V

    2001-03-01

    Cardiovascular reflex tests have shown both sympathetic and parasympathetic failure in Parkinson's disease. These tests, however, describe the autonomic responses during a restricted time period and have great individual variability, providing a limited view of the autonomic cardiac control mechanisms. Thus, they do not reflect tonic autonomic regulation. The aim was to examine tonic autonomic cardiovascular regulation in untreated patients with Parkinson's disease. 24 Hour ambulatory ECG was recorded in 54 untreated patients with Parkinson's disease and 47 age matched healthy subjects. In addition to the traditional spectral (very low frequency, VLF; low frequency, LF; high frequency, HF) and non-spectral components of heart rate variability, instantaneous beat to beat variability (SD1) and long term continuous variability (SD2) derived from Poincaré plots, and the slope of the power law relation were analysed. All spectral components (plaw relation (pParkinson's disease than in the control subjects. The Unified Parkinson's disease rating scale total and motor scores had a negative correlation with VLF and LF power spectrum values and the power law relation slopes. Patients with mild hypokinesia had higher HF values than patients with more severe hypokinesia. Tremor and rigidity were not associated with the HR variability parameters. Parkinson's disease causes dysfunction of the diurnal autonomic cardiovascular regulation as demonstrated by the spectral measures of heart rate variability and the slope of the power law relation. This dysfunction seems to be more profound in patients with more severe Parkinson's disease.

  10. Joint variable frame rate and length analysis for speech recognition under adverse conditions

    DEFF Research Database (Denmark)

    Tan, Zheng-Hua; Kraljevski, Ivan

    2014-01-01

    This paper presents a method that combines variable frame length and rate analysis for speech recognition in noisy environments, together with an investigation of the effect of different frame lengths on speech recognition performance. The method adopts frame selection using an a posteriori signal......-to-noise (SNR) ratio weighted energy distance and increases the length of the selected frames, according to the number of non-selected preceding frames. It assigns a higher frame rate and a normal frame length to a rapidly changing and high SNR region of a speech signal, and a lower frame rate and an increased...... frame length to a steady or low SNR region. The speech recognition results show that the proposed variable frame rate and length method outperforms fixed frame rate and length analysis, as well as standalone variable frame rate analysis in terms of noise-robustness....

  11. Tracking variable sedimentation rates in orbitally forced paleoclimate proxy series

    Science.gov (United States)

    Li, M.; Kump, L. R.; Hinnov, L.

    2017-12-01

    This study addresses two fundamental issues in cyclostratigraphy: quantitative testing of orbital forcing in cyclic sedimentary sequences and tracking variable sedimentation rates. The methodology proposed here addresses these issues as an inverse problem, and estimates the product-moment correlation coefficient between the frequency spectra of orbital solutions and paleoclimate proxy series over a range of "test" sedimentation rates. It is inspired by the ASM method (1). The number of orbital parameters involved in the estimation is also considered. The method relies on the hypothesis that orbital forcing had a significant impact on the paleoclimate proxy variations, and thus is also tested. The null hypothesis of no astronomical forcing is evaluated using the Beta distribution, for which the shape parameters are estimated using a Monte Carlo simulation approach. We introduce a metric to estimate the most likely sedimentation rate using the product-moment correlation coefficient, H0 significance level, and the number of contributing orbital parameters, i.e., the CHO value. The CHO metric is applied with a sliding window to track variable sedimentation rates along the paleoclimate proxy series. Two forward models with uniform and variable sedimentation rates are evaluated to demonstrate the robustness of the method. The CHO method is applied to the classical Late Triassic Newark depth rank series; the estimated sedimentation rates match closely with previously published sedimentation rates and provide a more highly time-resolved estimate (2,3). References: (1) Meyers, S.R., Sageman, B.B., Amer. J. Sci., 307, 773-792, 2007; (2) Kent, D.V., Olsen, P.E., Muttoni, G., Earth-Sci. Rev.166, 153-180, 2017; (3) Li, M., Zhang, Y., Huang, C., Ogg, J., Hinnov, L., Wang, Y., Zou, Z., Li, L., 2017. Earth Plant. Sc. Lett. doi:10.1016/j.epsl.2017.07.015

  12. Performance evaluation of a center pivot variable rate irrigation system

    Science.gov (United States)

    Variable Rate Irrigation (VRI) for center pivots offers potential to match specific application rates to non-uniform soil conditions along the length of the lateral. The benefit of such systems is influenced by the areal extent of these variations and the smallest scale to which the irrigation syste...

  13. Conventional to Cloud: Detailed survey and comparative study of multimedia streaming rate Adaptation

    OpenAIRE

    Selvaraj Kesavan; Jayakumar J

    2014-01-01

    Infotainment and telecommunication industry is fast evolving towards personalized network connectivity and newer applications services ranging from music playback to ever changing telephony applications. Streaming is the key services which enables the users to view real time multimedia content on-the-go anywhere and everywhere. In streaming, quality of service is a major concern in the increasing network traffic and high user demand. Rate adaptation is crucial process to dynamically evaluate,...

  14. The Effect of Exchange Rate Variability on U.S. Shareholder Wealth

    NARCIS (Netherlands)

    Müller, Aline; Verschoor, W.F.C.

    2009-01-01

    We examine the relationship between financial crisis exchange rate variability and equity return volatility for US multinationals. Empirical analysis of the major financial crises of the last decades reveals that stock return variability increases significantly in the aftermath of a crisis, even

  15. Effect of Heart Rate Variability Biofeedback on Sport Performance, a Systematic Review.

    Science.gov (United States)

    Jiménez Morgan, Sergio; Molina Mora, José Arturo

    2017-09-01

    Aim is to determine if the training with heart rate variability biofeedback allows to improve performance in athletes of different disciplines. Methods such as database search on Web of Science, SpringerLink, EBSCO Academic Search Complete, SPORTDiscus, Pubmed/Medline, and PROQUEST Academic Research Library, as well as manual reference registration. The eligibility criteria were: (a) published scientific articles; (b) experimental studies, quasi-experimental, or case reports; (c) use of HRV BFB as main treatment; (d) sport performance as dependent variable; (e) studies published until October 2016; (f) studies published in English, Spanish, French or Portuguese. The guidelines of the PRISMA statement were followed. Out of the 451 records found, seven items were included. All studies had a small sample size (range from 1 to 30 participants). In 85.71% of the studies (n = 6) the athletes enhanced psychophysiological variables that allowed them to improve their sport performance thanks to training with heart rate variability biofeedback. Despite the limited amount of experimental studies in the field to date, the findings suggest that heart rate variability biofeedback is an effective, safe, and easy-to-learn and apply method for both athletes and coaches in order to improve sport performance.

  16. Variable Rate, Adaptive Transform Tree Coding Of Images

    Science.gov (United States)

    Pearlman, William A.

    1988-10-01

    A tree code, asymptotically optimal for stationary Gaussian sources and squared error distortion [2], is used to encode transforms of image sub-blocks. The variance spectrum of each sub-block is estimated and specified uniquely by a set of one-dimensional auto-regressive parameters. The expected distortion is set to a constant for each block and the rate is allowed to vary to meet the given level of distortion. Since the spectrum and rate are different for every block, the code tree differs for every block. Coding simulations for target block distortion of 15 and average block rate of 0.99 bits per pel (bpp) show that very good results can be obtained at high search intensities at the expense of high computational complexity. The results at the higher search intensities outperform a parallel simulation with quantization replacing tree coding. Comparative coding simulations also show that the reproduced image with variable block rate and average rate of 0.99 bpp has 2.5 dB less distortion than a similarly reproduced image with a constant block rate equal to 1.0 bpp.

  17. Heart rate variability is reduced during acute uncomplicated diverticulitis

    DEFF Research Database (Denmark)

    Huang, Chenxi; Alamili, Mahdi; Rosenberg, Jacob

    2016-01-01

    BACKGROUND: The aim of the present study was to report the trajectory of heart rate variability (HRV) indices during a low-grade acute inflammation and their associations to biomarkers for infection. METHODS: Twelve patients with uncomplicated acute diverticulitis completed this observational study...

  18. A Latent-Variable Causal Model of Faculty Reputational Ratings.

    Science.gov (United States)

    King, Suzanne; Wolfle, Lee M.

    A reanalysis was conducted of Saunier's research (1985) on sources of variation in the National Research Council (NRC) reputational ratings of university faculty. Saunier conducted a stepwise regression analysis using 12 predictor variables. Due to problems with multicollinearity and because of the atheoretical nature of stepwise regression,…

  19. Heart rate variability | Lutfi | Sudan Journal of Medical Sciences

    African Journals Online (AJOL)

    An important outcome of such analysis is heart rate variability (HRV), which is widely accepted to have prognostic significance in patients with cardiovascular diseases especially after acute myocardial infarction. This is because HRV represents one of the most helpful markers of autonomic balance and hence can predict ...

  20. Who uses physician-rating websites? Differences in sociodemographic variables, psychographic variables, and health status of users and nonusers of physician-rating websites.

    Science.gov (United States)

    Terlutter, Ralf; Bidmon, Sonja; Röttl, Johanna

    2014-03-31

    The number of physician-rating websites (PRWs) is rising rapidly, but usage is still poor. So far, there has been little discussion about what kind of variables influence usage of PRWs. We focused on sociodemographic variables, psychographic variables, and health status of PRW users and nonusers. An online survey of 1006 randomly selected German patients was conducted in September 2012. We analyzed the patients' knowledge and use of online PRWs. We also analyzed the impact of sociodemographic variables (gender, age, and education), psychographic variables (eg, feelings toward the Internet, digital literacy), and health status on use or nonuse as well as the judgment of and behavior intentions toward PRWs. The survey instrument was based on existing literature and was guided by several research questions. A total of 29.3% (289/986) of the sample knew of a PRW and 26.1% (257/986) had already used a PRW. Younger people were more prone than older ones to use PRWs (t967=2.27, P=.02). Women used them more than men (χ(2) 1=9.4, P=.002), the more highly educated more than less educated people (χ(2) 4=19.7, P=.001), and people with chronic diseases more than people without (χ(2) 1=5.6, P=.02). No differences were found between users and nonusers in their daily private Internet use and in their use of the Internet for health-related information. Users had more positive feelings about the Internet and other Web-based applications in general (t489=3.07, P=.002) than nonusers, and they had higher digital literacy (t520=4.20, PUsers ascribed higher usefulness to PRWs than nonusers (t612=11.61, Pusers trusted information on PRWs to a greater degree than nonusers (t559=11.48, PUsers were also more likely to rate a physician on a PRW in the future (t367=7.63, Pincrease use of PRWs in the future.

  1. Heart Rate Variability and Drawing Impairment in Hypoxemic COPD

    Science.gov (United States)

    Incalzi, Raffaele Antonelli; Corsonello, Andrea; Trojano, Luigi; Pedone, Claudio; Acanfora, Domenico; Spada, Aldo; D'Addio, Gianni; Maestri, Roberto; Rengo, Franco; Rengo, Giuseppe

    2009-01-01

    We studied 54 patients with hypoxemic chronic obstructive pulmonary disease (COPD). The Mini Mental State Examination and the Mental Deterioration Battery were used for neuropsychological assessment. Heart rate variability (HRV) was assessed based on 24-h Holter ECG recording. Mann-Whitney test was used to compare HRV parameters of patients…

  2. Discrete rate and variable power adaptation for underlay cognitive networks

    KAUST Repository

    Abdallah, Mohamed M.; Salem, Ahmed H.; Alouini, Mohamed-Slim; Qaraqe, Khalid A.

    2010-01-01

    We consider the problem of maximizing the average spectral efficiency of a secondary link in underlay cognitive networks. In particular, we consider the network setting whereby the secondary transmitter employs discrete rate and variable power

  3. Evaluation of sympathetic nerve system activity with MIBG. Comparison with heart rate variability

    International Nuclear Information System (INIS)

    Kurata, Chinori; Wakabayashi, Yasushi; Shouda, Sakae; Mikami, Tadashi; Tawarahara, Kei; Sugiyama, Tsuyoshi; Nakano, Tomoyasu; Suzuki, Toshihiko.

    1997-01-01

    Authors attempted to elucidate the relations of plasma concentration of norepinephrine (pNE) and findings of heart rate variability and MIBG myocardial scintigraphy and evaluated cardiac autonomic nervous activity in chronic renal failure. Subjects were 211 patients with various heart diseases (coronary artery lesion, cardiomyopathy, hypertension, diabetes mellitus, renal failure and so on), 60 patients with artificial kidney due to chronic renal failure, 13 of whom were found to have coronary arterial disease by Tl myocardial scintigraphy, and 14 normal volunteers. ECG was recorded with the portable recorder for heart rate variability. Together with collection of blood for pNE measurement, myocardial scintigraphy was done at 15 and 150 min after intravenous administration of 111 MBq of MIBG for acquisition of early and delayed, respectively, images of the frontal breast. Accumulation at and elimination during the time points of MIBG were computed in cps unit. Variability of heart rate was found to have the correlation positive with MIBG delayed accumulation and negative with the elimination, and pNE, negative with heart rate variability and the delayed accumulation and positive with the elimination. Thus cardiac autonomic nervous abnormality was suggested to occur before uremic cardiomyopathy. (K.H.)

  4. General anesthesia suppresses normal heart rate variability in humans

    Science.gov (United States)

    Matchett, Gerald; Wood, Philip

    2014-06-01

    The human heart normally exhibits robust beat-to-beat heart rate variability (HRV). The loss of this variability is associated with pathology, including disease states such as congestive heart failure (CHF). The effect of general anesthesia on intrinsic HRV is unknown. In this prospective, observational study we enrolled 100 human subjects having elective major surgical procedures under general anesthesia. We recorded continuous heart rate data via continuous electrocardiogram before, during, and after anesthesia, and we assessed HRV of the R-R intervals. We assessed HRV using several common metrics including Detrended Fluctuation Analysis (DFA), Multifractal Analysis, and Multiscale Entropy Analysis. Each of these analyses was done in each of the four clinical phases for each study subject over the course of 24 h: Before anesthesia, during anesthesia, early recovery, and late recovery. On average, we observed a loss of variability on the aforementioned metrics that appeared to correspond to the state of general anesthesia. Following the conclusion of anesthesia, most study subjects appeared to regain their normal HRV, although this did not occur immediately. The resumption of normal HRV was especially delayed on DFA. Qualitatively, the reduction in HRV under anesthesia appears similar to the reduction in HRV observed in CHF. These observations will need to be validated in future studies, and the broader clinical implications of these observations, if any, are unknown.

  5. Fabrication and evaluation of variable rate fertilizer system

    Directory of Open Access Journals (Sweden)

    A Damirchi

    2015-09-01

    Full Text Available Introduction: In conventional farming, the soil and crop are considered uniform in different locations of the farm and the fertilizers are applied according to the average of soil needs with an additional percentage for safety (Loghavi, 2003. Non-essential chemical fertilizers in the field have harmful effects and social, economic and environmental concerns will increase. Many fertilizers go into the surface waters and ground waters and cause poisoning and environmental pollution without being absorbed by the plants. In variable rate technology, the soil fertilizer needs a map of all parts of the farm which is prepared with the GIS system. This map is uploaded on the computer before variable rate fertilizer machine starts. The computer continually controls the fertilizing rate for each part of the farm using a fertilizing map and global positioning system. The purpose of this study is to construct and evaluate a map-based variable rate fertilizer system that can be installed on a common fertilizer in Iran to be used as a variable rate system. Materials and methods: In common variable rate fertilizers, the rotational speed change of the distributor shaft is used to apply fertilizers. In this way, a DC motor is assembled on the main shaft of all distributors, which reduces the fertilizing accuracy. The reason for this is that there is no separation for units along the width of the fertilizer. Therefore, we used one DC motor for each distributor and another motor to rotate the agitator in the tank. System Set up: To design and select a suitable engine, the required torque for the rotation distributor shaft was measured by a torque meter and the amount of 2.1 Nm was acquired for that. With regard to the maximum rate of nitrogen fertilizer for land and tractor speed at the time of fertilizing, the order of 350 kg per hectare and 8 km per hour, the maximum distributor shaft speed and power required to rotate distributor shaft were calculated to be 55

  6. Variable mutation rates as an adaptive strategy in replicator populations.

    Directory of Open Access Journals (Sweden)

    Michael Stich

    2010-06-01

    Full Text Available For evolving populations of replicators, there is much evidence that the effect of mutations on fitness depends on the degree of adaptation to the selective pressures at play. In optimized populations, most mutations have deleterious effects, such that low mutation rates are favoured. In contrast to this, in populations thriving in changing environments a larger fraction of mutations have beneficial effects, providing the diversity necessary to adapt to new conditions. What is more, non-adapted populations occasionally benefit from an increase in the mutation rate. Therefore, there is no optimal universal value of the mutation rate and species attempt to adjust it to their momentary adaptive needs. In this work we have used stationary populations of RNA molecules evolving in silico to investigate the relationship between the degree of adaptation of an optimized population and the value of the mutation rate promoting maximal adaptation in a short time to a new selective pressure. Our results show that this value can significantly differ from the optimal value at mutation-selection equilibrium, being strongly influenced by the structure of the population when the adaptive process begins. In the short-term, highly optimized populations containing little variability respond better to environmental changes upon an increase of the mutation rate, whereas populations with a lower degree of optimization but higher variability benefit from reducing the mutation rate to adapt rapidly. These findings show a good agreement with the behaviour exhibited by actual organisms that replicate their genomes under broadly different mutation rates.

  7. Decreased heart rate variability in surgeons during night shifts

    DEFF Research Database (Denmark)

    Amirian, Ilda; Toftegård Andersen, Lærke; Rosenberg, Jacob

    2014-01-01

    BACKGROUND: Heart rate variability (HRV) has been used as a measure of stress and mental strain in surgeons. Low HRV has been associated with death and increased risk of cardiac events in the general population. The aim of this study was to clarify the effect of a 17-hour night shift on surgeons'...

  8. Heart-rate variability and precompetitive anxiety in swimmers

    OpenAIRE

    Cervantes Blásquez, Julio César

    2009-01-01

    The aim of this study was to test the utility of heart-rate variability (HRV) analyses as a noninvasive means of quantifying cardiac autonomic regulation during precompetitive anxiety situations in swimmers. Psychophysiological state evaluation of 10 volunteer «master» swimmers (6 women and 4 men) was obtained by comparing baseline training condition (TC) with competition condition (CC). Self-evaluation of precompetitive somatic anxiety measured by CSAI-2 showed significant increase from the ...

  9. Increased heart rate variability during nondirective meditation.

    Science.gov (United States)

    Nesvold, Anders; Fagerland, Morten W; Davanger, Svend; Ellingsen, Øyvind; Solberg, Erik E; Holen, Are; Sevre, Knut; Atar, Dan

    2012-08-01

    Meditation practices are in use for relaxation and stress reduction. Some studies indicate beneficial cardiovascular health effects of meditation. The effects on the autonomous nervous system seem to vary among techniques. The purpose of the present study was to identify autonomic nerve activity changes during nondirective meditation. Heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) were monitored in 27 middle-aged healthy participants of both genders, first during 20 min regular rest with eyes closed, thereafter practising Acem meditation for 20 min. Haemodynamic and autonomic data were collected continuously (beat-to-beat) and non-invasively. HRV and BPV parameters were estimated by power spectral analyses, computed by an autoregressive model. Spontaneous activity of baroreceptors were determined by the sequence method. Primary outcomes were changes in HRV, BPV, and BRS between rest and meditation. HRV increased in the low-frequency (LF) and high-frequency (HF) bands during meditation, compared with rest (p = 0.014, 0.013, respectively). Power spectral density of the RR-intervals increased as well (p = 0.012). LF/HF ratio decreased non-significantly, and a reduction of LF-BPV power was observed during meditation (p < 0.001). There was no significant difference in BRS. Respiration and heart rates remained unchanged. Blood pressure increased slightly during meditation. There is an increased parasympathetic and reduced sympathetic nerve activity and increased overall HRV, while practising the technique. Hence, nondirective meditation by the middle aged may contribute towards a reduction of cardiovascular risk.

  10. Effect of flow rate on environmental variables and phytoplankton dynamics: results from field enclosures

    Science.gov (United States)

    Zhang, Haiping; Chen, Ruihong; Li, Feipeng; Chen, Ling

    2015-03-01

    To investigate the effects of flow rate on phytoplankton dynamics and related environment variables, a set of enclosure experiments with different flow rates were conducted in an artificial lake. We monitored nutrients, temperature, dissolved oxygen, pH, conductivity, turbidity, chlorophyll- a and phytoplankton levels. The lower biomass in all flowing enclosures showed that flow rate significantly inhibited the growth of phytoplankton. A critical flow rate occurred near 0.06 m/s, which was the lowest relative inhibitory rate. Changes in flow conditions affected algal competition for light, resulting in a dramatic shift in phytoplankton composition, from blue-green algae in still waters to green algae in flowing conditions. These findings indicate that critical flow rate can be useful in developing methods to reduce algal bloom occurrence. However, flow rate significantly enhanced the inter-relationships among environmental variables, in particular by inducing higher water turbidity and vegetative reproduction of periphyton ( Spirogyra). These changes were accompanied by a decrease in underwater light intensity, which consequently inhibited the photosynthetic intensity of phytoplankton. These results warn that a universal critical flow rate might not exist, because the effect of flow rate on phytoplankton is interlinked with many other environmental variables.

  11. The effect of metaprolol alone and metaprolol plus bromazepam on heart rate and heart rate variability during multislice computed tomography angiography

    International Nuclear Information System (INIS)

    Tuyyab, F.; Naeem, M.Y.; Maken, G.R.; Najfi, M.H.; Hassan, F.

    2012-01-01

    Objective: The purpose of this study was to determine the effect of metaprolol alone and metaprolol plus bromazepam on heart rate and heart rate variability during multi slice computed tomography (MSCT) angiography. Methodology: This was a Double blind randomized controlled trial was conducted at AFIC/NIHD, Rawalpindi, from May 2011 to November 2011. Patients undergoing first MSCT angiography meeting inclusion criteria with heart rates (HR) more than 80 beats/min were included. Patients were randomized in to two groups using random numbers table. Group 1 was administered metaprolol plus placebo while group 2 was administered metaprolol plus bromazepam one hour before the scan. Both groups had scans under strictly similar conditions. HR before and during scan along with heart rate variability (HRV) were recorded. Results: A total of 80 patients were included. Patients mean age was 49 + 13, 57 % were males while 43 % were females. Risk factor profile was similar in both groups. HR reduction in group 1 was 15+ 6.0 and in group 2, was 21+9.0 (p= 0.002). HRV in group 1 was 3.9 + 1.32 and in group 2 was 2.3 + 1.0 (p= 0.003). Group 2 had significantly lower HR and significantly less HRV as compared with group 1. Conclusion: Combination of bromazepam and metaprolol results in significant and further reduction in heart rate and heart rate variability than metaprolol alone. Both drugs can be used together for a better control of heart rate and heart rate variability during MSCT angiography for improving the quality of images. (author)

  12. Play-back theatre, theatre laboratory, and role-playing: new tools in investigating the patient-physician relationship in the context of continuing medical education courses.

    Science.gov (United States)

    Piccoli, G; Rossetti, M; Dell'Olio, R; Perrotta, L; Mezza, E; Burdese, M; Maddalena, E; Bonetto, A; Jeantet, A; Segoloni, G P

    2005-06-01

    The aim of this study was to report on the validation of a role-playing approach, using play-back and theatre laboratory in the context of a continuing medical education (CME) course on predialysis and transplantation, to discuss the patient-physician relationship. The course was developed with the help of a theatre director. The role-playing 2-day course was designed to be highly interactive for a small group (15-20 participants), based on a core of case reports (dialysis, transplantation, and return to dialysis after graft failure). Two stages were included: play-back theatre in which experiences told by the participants were mimed by a group of actors, and theatre laboratory in which different aspects of voice and touch were explored. Opinions were gathered by an anonymous semistructured questionnaire completed by all participants. The course obtained a high score from The Ministry of Health (14 credits, 1 per teaching hour). The opinions of the 18 participants were highly positive; all liked the courses. Sixteen of 18 asked to repeat the experience. The strong emotional involvement was an advantage for 15 of 18, sharing emotional aspects of the profession for 10 of 18, and usefulness in clarifying opinions on "dark sides" of our profession for 10 of 18. The positive opinions recorded during this experience, the first experiment with a "psycho-theatrical approach" developed in a CME course in our country, suggest the benefit of implementing nonconventional, educational approaches in a multidisciplinary discussion of the patient-physician relationship in transplantation medicine.

  13. Heart-Rate Variability-More than Heart Beats?

    Science.gov (United States)

    Ernst, Gernot

    2017-01-01

    Heart-rate variability (HRV) is frequently introduced as mirroring imbalances within the autonomous nerve system. Many investigations are based on the paradigm that increased sympathetic tone is associated with decreased parasympathetic tone and vice versa . But HRV is probably more than an indicator for probable disturbances in the autonomous system. Some perturbations trigger not reciprocal, but parallel changes of vagal and sympathetic nerve activity. HRV has also been considered as a surrogate parameter of the complex interaction between brain and cardiovascular system. Systems biology is an inter-disciplinary field of study focusing on complex interactions within biological systems like the cardiovascular system, with the help of computational models and time series analysis, beyond others. Time series are considered surrogates of the particular system, reflecting robustness or fragility. Increased variability is usually seen as associated with a good health condition, whereas lowered variability might signify pathological changes. This might explain why lower HRV parameters were related to decreased life expectancy in several studies. Newer integrating theories have been proposed. According to them, HRV reflects as much the state of the heart as the state of the brain. The polyvagal theory suggests that the physiological state dictates the range of behavior and psychological experience. Stressful events perpetuate the rhythms of autonomic states, and subsequently, behaviors. Reduced variability will according to this theory not only be a surrogate but represent a fundamental homeostasis mechanism in a pathological state. The neurovisceral integration model proposes that cardiac vagal tone, described in HRV beyond others as HF-index, can mirror the functional balance of the neural networks implicated in emotion-cognition interactions. Both recent models represent a more holistic approach to understanding the significance of HRV.

  14. What Does Eye-Blink Rate Variability Dynamics Tell Us About Cognitive Performance?

    Directory of Open Access Journals (Sweden)

    Rafal Paprocki

    2017-12-01

    Full Text Available Cognitive performance is defined as the ability to utilize knowledge, attention, memory, and working memory. In this study, we briefly discuss various markers that have been proposed to predict cognitive performance. Next, we develop a novel approach to characterize cognitive performance by analyzing eye-blink rate variability dynamics. Our findings are based on a sample of 24 subjects. The subjects were given a 5-min resting period prior to a 10-min IQ test. During both stages, eye blinks were recorded from Fp1 and Fp2 electrodes. We found that scale exponents estimated for blink rate variability during rest were correlated with subjects' performance on the subsequent IQ test. This surprising phenomenon could be explained by the person to person variation in concentrations of dopamine in PFC and accumulation of GABA in the visual cortex, as both neurotransmitters play a key role in cognitive processes and affect blinking. This study demonstrates the possibility that blink rate variability dynamics at rest carry information about cognitive performance and can be employed in the assessment of cognitive abilities without taking a test.

  15. Attempt to determine radon entry rate and air exchange rate variable in time from the time course of indoor radon concentration

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, J [State Office for Nuclear Protection, Prague (Czech Republic)

    1996-12-31

    For radon diagnosis in houses the `ventilation experiment` was used as a standard method. After removal of indoor radon by draught the build-up of radon concentration a(t) [Bq/m{sup 3}] was measured continuously and from the time course the constant radon entry rate A [Bq/h] and the exchange rate k [h{sup -1}] was calculated by regression analysis using model relation a(t) A(1-e{sup -kt})/kV with V [m{sup 3}] for volume of the room. The conditions have to be stable for several hours so that the assumption of constant A and k was justified. During the day both quantities were independently (?) changing, therefore a method to determine variable entry rate A(t) and exchange rate k(t) is needed for a better understanding of the variability of the indoor radon concentration. Two approaches are given for the determination of variable in time radon entry rates and air exchange rates from continuously measured indoor radon concentration - numerical solution of the equivalent difference equations in deterministic or statistic form. The approaches are not always successful. Failures giving a right ration for the searched rates but not of the rates them self could not be explained.

  16. Relative influence of age, resting heart rate and sedentary life style in short-term analysis of heart rate variability

    OpenAIRE

    E.R. Migliaro; P. Contreras; S. Bech; A. Etxagibel; M. Castro; R. Ricca; K. Vicente

    2001-01-01

    In order to assess the relative influence of age, resting heart rate (HR) and sedentary life style, heart rate variability (HRV) was studied in two different groups. The young group (YG) consisted of 9 sedentary subjects aged 15 to 20 years (YG-S) and of 9 nonsedentary volunteers (YG-NS) also aged 15 to 20. The elderly sedentary group (ESG) consisted of 16 sedentary subjects aged 39 to 82 years. HRV was assessed using a short-term procedure (5 min). R-R variability was calculated in the time-...

  17. Validity of (Ultra-)Short Recordings for Heart Rate Variability Measurements

    NARCIS (Netherlands)

    Muñoz Venegas, Loretto; van Roon, Arie; Riese, Harriette; Thio, Chris; Oostenbroek, Emma; Westrik, Iris; de Geus, Eco J. C.; Gansevoort, Ron; Lefrandt, Joop; Nolte, Ilja M.; Snieder, Harold

    2015-01-01

    Objectives In order to investigate the applicability of routine 10s electrocardiogram (ECG) recordings for time-domain heart rate variability (HRV) calculation we explored to what extent these (ultra-)short recordings capture the "actual" HRV. Methods The standard deviation of normal-to-normal

  18. Individual variability in heart rate recovery after standardized submaximal exercise

    NARCIS (Netherlands)

    van der Does, Hendrike; Brink, Michel; Visscher, Chris; Lemmink, Koen

    2012-01-01

    To optimize performance, coaches and athletes are always looking for the right balance between training load and recovery. Therefore, closely monitoring of athletes is important. Heart rate recovery (HRR) after standardized sub maximal exercise has been proposed as a useful variable to monitor

  19. THE RELATIONSHIP BETWEEN MACROECONOMIC VARIABLES AND ROMANIAN CORPORATE DEFAULT RATES BETWEEN 2002-2008

    Directory of Open Access Journals (Sweden)

    Suveg Orsolya

    2011-07-01

    Full Text Available During its 20 year history of market economy, Romania experienced the most severe downturn in 2009, which resulted in many cost, mainly because of the output loss. These conditions forced several firms to declare bankruptcy and to stop their activity. The aim of this research is to assess the relationship between the corporate default rates and the macroeconomic processes in the case of Romania for the period comprised between 2002Q1-2008Q4. For this, based on the relevant literature, we ranked the potential explanatory variables of the default rates into seven groups: cyclical indicators, household indicators, corporate indicators, external sector indicators, price stability indicators and interest rates, loans to private sector and finally the capital market indicators. Some studies base their results only on accounting data, others only on market data. Our study focuses on both, since this seems to be an adequate approach in capturing most of the processes. Similar to the banks loan portfolio structure, we conducted analysis for five sectors: industry, construction, agriculture, services and the overall economy. For each sector the average default probability at time t is modeled as a logistic function of many general and sector-specific macroeconomic variables. The use of logistic regression was motivated by its ability to account for fractional data between 0 and 1. We found that at least one variable from each group has a significant explanatory power regarding the evolution of the default rates in all five sectors analyzed. In some cases the sign of the variables was the opposite of what the economic theory would have suggested, but it has to be taken into account that Romania posted the picture of an overheated economy during the analyzed period. Another important conclusion was that many variables were significant through their lagged value, which indicates an even better supervision of the evolution of the specific variables. From all

  20. Statistical analysis of nuclear power plant pump failure rate variability: some preliminary results

    International Nuclear Information System (INIS)

    Martz, H.F.; Whiteman, D.E.

    1984-02-01

    In-Plant Reliability Data System (IPRDS) pump failure data on over 60 selected pumps in four nuclear power plants are statistically analyzed using the Failure Rate Analysis Code (FRAC). A major purpose of the analysis is to determine which environmental, system, and operating factors adequately explain the variability in the failure data. Catastrophic, degraded, and incipient failure severity categories are considered for both demand-related and time-dependent failures. For catastrophic demand-related pump failures, the variability is explained by the following factors listed in their order of importance: system application, pump driver, operating mode, reactor type, pump type, and unidentified plant-specific influences. Quantitative failure rate adjustments are provided for the effects of these factors. In the case of catastrophic time-dependent pump failures, the failure rate variability is explained by three factors: reactor type, pump driver, and unidentified plant-specific influences. Finally, point and confidence interval failure rate estimates are provided for each selected pump by considering the influential factors. Both types of estimates represent an improvement over the estimates computed exclusively from the data on each pump

  1. Variable beam dose rate and DMLC IMRT to moving body anatomy

    International Nuclear Information System (INIS)

    Papiez, Lech; Abolfath, Ramin M.

    2008-01-01

    Derivation of formulas relating leaf speeds and beam dose rates for delivering planned intensity profiles to static and moving targets in dynamic multileaf collimator (DMLC) intensity modulated radiation therapy (IMRT) is presented. The analysis of equations determining algorithms for DMLC IMRT delivery under a variable beam dose rate reveals a multitude of possible delivery strategies for a given intensity map and for any given target motion patterns. From among all equivalent delivery strategies for DMLC IMRT treatments specific subclasses of strategies can be selected to provide deliveries that are particularly suitable for clinical applications providing existing delivery devices are used. Special attention is devoted to the subclass of beam dose rate variable DMLC delivery strategies to moving body anatomy that generalize existing techniques of such deliveries in Varian DMLC irradiation methodology to static body anatomy. Few examples of deliveries from this subclass of DMLC IMRT irradiations are investigated to illustrate the principle and show practical benefits of proposed techniques.

  2. Variable beam dose rate and DMLC IMRT to moving body anatomy

    Energy Technology Data Exchange (ETDEWEB)

    Papiez, Lech; Abolfath, Ramin M. [Department of Radiation Oncology, UTSouthwestern Medical Center, Dallas, Texas 75390 (United States)

    2008-11-15

    Derivation of formulas relating leaf speeds and beam dose rates for delivering planned intensity profiles to static and moving targets in dynamic multileaf collimator (DMLC) intensity modulated radiation therapy (IMRT) is presented. The analysis of equations determining algorithms for DMLC IMRT delivery under a variable beam dose rate reveals a multitude of possible delivery strategies for a given intensity map and for any given target motion patterns. From among all equivalent delivery strategies for DMLC IMRT treatments specific subclasses of strategies can be selected to provide deliveries that are particularly suitable for clinical applications providing existing delivery devices are used. Special attention is devoted to the subclass of beam dose rate variable DMLC delivery strategies to moving body anatomy that generalize existing techniques of such deliveries in Varian DMLC irradiation methodology to static body anatomy. Few examples of deliveries from this subclass of DMLC IMRT irradiations are investigated to illustrate the principle and show practical benefits of proposed techniques.

  3. Wide Variability in Emergency Physician Admission Rates: A Target to Reduce Costs Without Compromising Quality

    Directory of Open Access Journals (Sweden)

    Jeffrey J. Guterman

    2016-09-01

    Full Text Available Introduction: Attending physician judgment is the traditional standard of care for emergency department (ED admission decisions. The extent to which variability in admission decisions affect cost and quality is not well understood. We sought to determine the impact of variability in admission decisions on cost and quality. Methods: We performed a retrospective observational study of patients presenting to a university-affiliated, urban ED from October 1, 2007, through September 30, 2008. The main outcome measures were admission rate, fiscal indicators (Medicaid-denied payment days, and quality indicators (15- and 30-day ED returns; delayed hospital admissions. We asked each Attending to estimate their inpatient admission rate and correlated their personal assessment with actual admission rates. Results: Admission rates, even after adjusting for known confounders, were highly variable (15.2%-32.0% and correlated with Medicaid denied-payment day rates (p=0.038. There was no correlation with quality outcome measures (30-day ED return or delayed hospital admission. There was no significant correlation between actual and self-described admission rate; the range of mis-estimation was 0% to 117%. Conclusion: Emergency medicine attending admission rates at this institution are highly variable, unexplained by known confounding variables, and unrelated to quality of care, as measured by 30-day ED return or delayed hospital admission. Admission optimization represents an important untapped potential for cost reduction through avoidable hospitalizations, with no apparent adverse effects on quality.

  4. Heart rate variability changes in physicians working on night call.

    Science.gov (United States)

    Malmberg, Birgitta; Persson, Roger; Flisberg, Per; Ørbaek, Palle

    2011-03-01

    Adverse effects by night-call duty have become an important occupational health issue. The aim of this study was to investigate whether the heart rate variability (HRV) differed during recovery from day work and night-call duty between distinct physician specialities. We studied the impact of a 16-h night-call duty on autonomic balance, measured by HRV, among two physician groups differing with respect to having to deal with life-threatening conditions while on call. Nineteen anaesthesiologists (ANEST) and 16 paediatricians and ear, nose and throat surgeons (PENT) were monitored by ambulatory digital Holter electrocardiogram (ECG). Heart rate variability was analysed between 21:00 and 22:00 after an ordinary workday, on night call and in the evening post-call. Absolute and normalized high-frequency power (HF, HFnu) were the main outcome variables, expressing parasympathetic influence on the heart. ANEST had lower HF power than PENT while on night call and post-daytime work (p work compared with post-night-call duty (p balance and did not differ between specialities. However, the less dynamic HRV after daytime work and during night-call duty in the ANEST group may indicate a higher physiological stress level. These results may contribute to the improvement of night-call schedules within the health care sector.

  5. Dynamics of a seismogenic fault subject to variable strain rate

    OpenAIRE

    M. Dragoni; A. Piombo

    2011-01-01

    The behaviour of seismogenic faults is generally investigated under the assumption that they are subject to a constant strain rate. We consider the effect of a slowly variable strain rate on the recurrence times of earthquakes generated by a single fault. To this aim a spring-block system is employed as a low-order analog of the fault. Two cases are considered: a sinusoidal oscillation in the driver velocity and a monotonic change from one velocity value to another. In the f...

  6. State-related differences in heart rate variability in bipolar disorder

    DEFF Research Database (Denmark)

    Faurholt-Jepsen, Maria; Brage, Søren; Kessing, Lars Vedel

    2017-01-01

    Heart rate variability (HRV) is a validated measure of sympato-vagal balance in the autonomic nervous system. HRV appears decreased in patients with bipolar disorder (BD) compared with healthy individuals, but the extent of state-related alterations has been sparingly investigated. The present...... bipolar disorder and could...

  7. Leukocyte Populations are Associated with Heart Rate Variability After a Triathlon

    Directory of Open Access Journals (Sweden)

    Cruz Germán Hernández

    2016-12-01

    Full Text Available The purpose of this study was to analyze cellular immune components and their association with heart rate variability in triathlon athletes. Twelve athletes were included (age 36.41 ± 5.57 years, body mass 81.84 ± 10.97 kg and blood samples were taken one week before, immediately, at 2 and 48 hours, and one week after competition. Total lymphocytes and their subpopulations, neutrophils, basophils, eosinophils and monocytes were analyzed. At the same time, heart rate variability was recorded for 30 minutes using Polar Team2®. A significant difference between lymphocyte subpopulations and heart rate variability was found in the different study periods. A positive correlation was found between total lymphocytes and rMSSD (r = .736, p <0.05, CD3+ and rMSSD (r = .785, p <0.05, and CD4+ and rMSSD (r = .795, p < 0.05 at the end of the competition. After one week of competition, a negative correlation was found between eosinophils and MRR, SDNN, pNN50, and rMSSD (p <0.01; and basophils and MRR, SDNN, pNN50, and rMSSD (p <0.01; while a positive correlation was found between CD19+ (B cells and pNN50 (r = .678, p <0.05. Our results suggest that it is possible to predict the effect of training with regard to the athlete's performance.

  8. Combinatorial effect of nicotine and black tea on heart rate variability: Useful or harmful?

    Science.gov (United States)

    Joukar, S; Sheibani, M

    2017-06-01

    The effect of nicotine on heart rate variability (HRV) is controversial. Autonomic nervous system is the main regulator of heart rhythm, and heart rate variability is an appropriate index to assessment of the effects of the autonomic system on heart. In this study, the combination effect of nicotine and black tea consumption on sympatho-vagal balance and heart rate variability was investigated in rats. Male Wistar rats were randomized into four groups as control, tea (2.5 g/100 cc, daily), nicotine (2 mg/kg/d) and tea plus nicotine groups which treated for 28 days, and in the 29th day, their electrocardiograms (lead II) were recorded. The mean of high-frequency power (HF) in tea, nicotine and tea plus nicotine groups was significantly more than control group (P nicotine and tea + nicotine groups was significantly less than control group (P nicotine and tea + nicotine groups in comparison with control group (P nicotine or their combination with dosages used in this study can increase the heart rate variability and improve the sympatho-vagal balance in rat. © 2017 John Wiley & Sons Ltd.

  9. Word-serial Architectures for Filtering and Variable Rate Decimation

    Directory of Open Access Journals (Sweden)

    Eugene Grayver

    2002-01-01

    Full Text Available A new flexible architecture is proposed for word-serial filtering and variable rate decimation/interpolation. The architecture is targeted for low power applications requiring medium to low data rate and is ideally suited for implementation on either an ASIC or an FPGA. It combines the small size and low power of an ASIC with the programmability and flexibility of a DSP. An efficient memory addressing scheme eliminates the need for power hungry shift registers and allows full reconfiguration. The decimation ratio, filter length and filter coefficients can all be changed in real time. The architecture takes advantage of coefficient symmetries in linear phase filters and in polyphase components.

  10. Photoplethysmography pulse rate variability as a surrogate measurement of heart rate variability during non-stationary conditions

    International Nuclear Information System (INIS)

    Gil, E; Orini, M; Bailón, R; Laguna, P; Vergara, J M; Mainardi, L

    2010-01-01

    In this paper we assessed the possibility of using the pulse rate variability (PRV) extracted from the photoplethysmography signal as an alternative measurement of the HRV signal in non-stationary conditions. The study is based on analysis of the changes observed during a tilt table test in the heart rate modulation of 17 young subjects. First, the classical indices of HRV analysis were compared to the indices from PRV in intervals where stationarity was assumed. Second, the time-varying spectral properties of both signals were compared by time-frequency (TF) and TF coherence analysis. Third, the effect of replacing PRV with HRV in the assessment of the changes of the autonomic modulation of the heart rate was considered. Time-invariant HRV and PRV indices showed no statistically significant differences (p > 0.05) and high correlation (>0.97). Time-frequency analysis revealed that the TF spectra of both signals were highly correlated (0.99 ± 0.01); the difference between the instantaneous power, in the LF and HF bands, obtained from HRV and PRV was small (<10 −3 s −2 ) and their temporal patterns were highly correlated (0.98 ± 0.04 and 0.95 ± 0.06 in the LF and HF bands, respectively) and TF coherence in the LF and HF bands was high (0.97 ± 0.04 and 0.89 ± 0.08, respectively). Finally, the instantaneous power in the LF band was observed to significantly increase during head-up tilt by both HRV and PRV analysis. These results suggest that although some differences in the time-varying spectral indices extracted from HRV and PRV exist, mainly in the HF band associated with respiration, PRV could be used as a surrogate of HRV during non-stationary conditions, at least during the tilt table test

  11. Heart rate and flow velocity variability as determined from umbilical Doppler velocimetry at 10-20 weeks of gestation.

    Science.gov (United States)

    Ursem, N T; Struijk, P C; Hop, W C; Clark, E B; Keller, B B; Wladimiroff, J W

    1998-11-01

    1. The aim of this study was to define from umbilical artery flow velocity waveforms absolute peak systolic and time-averaged velocity, fetal heart rate, fetal heart rate variability and flow velocity variability, and the relation between fetal heart rate and velocity variables in early pregnancy.2.A total of 108 women presenting with a normal pregnancy from 10 to 20 weeks of gestation consented to participate in a cross-sectional study design. Doppler ultrasound recordings were made from the free-floating loop of the umbilical cord.3. Umbilical artery peak systolic and time-averaged velocity increased at 10-20 weeks, whereas fetal heart rate decreased at 10-15 weeks of gestation and plateaued thereafter. Umbilical artery peak systolic velocity variability and fetal heart rate variability increased at 10-20 and 15-20 weeks respectively.4. The inverse relationship between umbilical artery flow velocity and fetal heart rate at 10-15 weeks of gestation suggests that the Frank-Starling mechanism regulates cardiovascular control as early as the late first and early second trimesters of pregnancy. A different underlying mechanism is suggested for the observed variability profiles in heart rate and umbilical artery peak systolic velocity. It is speculated that heart rate variability is mediated by maturation of the parasympathetic nervous system, whereas peak systolic velocity variability reflects the activation of a haemodynamic feedback mechanism.

  12. [Voluntary alpha-power increasing training impact on the heart rate variability].

    Science.gov (United States)

    Bazanova, O M; Balioz, N V; Muravleva, K B; Skoraia, M V

    2013-01-01

    In order to study the effect of the alpha EEG power increasing training at heart rate variability (HRV) as the index of the autonomic regulation of cognitive functions there were follow tasks: (1) to figure out the impact of biofeedback in the voluntary increasing the power in the individual high-frequency alpha-band effect on heart rate variability and related characteristics of cognitive and emotional spheres, (2) to determine the nature of the relationship between alpha activity indices and heart rate variability, depending on the alpha-frequency EEG pattern at rest (3) to examine how the individual alpha frequency EEG pattern is reflected in changes HRV as a result of biofeedback training. Psychometric indicators of cognitive performance, the characteristics of the alpha-EEG activity and heart rate variability (HRV) as LF/HF and pNN50 were recorded in 27 healthy men aged 18-34 years, before, during, and after 10 sessions of training of voluntary increase in alpha power in the individual high-frequency alpha band with eyes closed. To determine the biofeedback effect on the alpha power increasing training, data subjects are compared in 2 groups: experimental (14) with the real and the control group (13 people)--with mock biofeedback. The follow up effect of trainings was studied through month over the 10 training sessions. Results showed that alpha biofeedback training enhanced the fluency and accuracy in cognitive performance, decreased anxiety and frontal EMG, increased resting frequency, width and power in individual upper alpha range only in participants with low baseline alpha frequency. While mock biofeedback increased resting alpha power only in participants with high baseline resting alpha frequency and did change neither cognitive performance, nor HRV indices. Biofeedback training eliminated the alpha power decrease in response to arithmetic task in both with high and low alpha frequency participants and this effect was followed up over the month. Mock

  13. Validation of Heart Rate Monitor Polar RS800 for Heart Rate Variability Analysis During Exercise.

    Science.gov (United States)

    Hernando, David; Garatachea, Nuria; Almeida, Rute; Casajús, Jose A; Bailón, Raquel

    2018-03-01

    Hernando, D, Garatachea, N, Almeida, R, Casajús, JA, and Bailón, R. Validation of heart rate monitor Polar RS800 for heart rate variability analysis during exercise. J Strength Cond Res 32(3): 716-725, 2018-Heart rate variability (HRV) analysis during exercise is an interesting noninvasive tool to measure the cardiovascular response to the stress of exercise. Wearable heart rate monitors are a comfortable option to measure interbeat (RR) intervals while doing physical activities. It is necessary to evaluate the agreement between HRV parameters derived from the RR series recorded by wearable devices and those derived from an electrocardiogram (ECG) during dynamic exercise of low to high intensity. Twenty-three male volunteers performed an exercise stress test on a cycle ergometer. Subjects wore a Polar RS800 device, whereas ECG was also recorded simultaneously to extract the reference RR intervals. A time-frequency spectral analysis was performed to extract the instantaneous mean heart rate (HRM), and the power of low-frequency (PLF) and high-frequency (PHF) components, the latter centered on the respiratory frequency. Analysis was done in intervals of different exercise intensity based on oxygen consumption. Linear correlation, reliability, and agreement were computed in each interval. The agreement between the RR series obtained from the Polar device and from the ECG is high throughout the whole test although the shorter the RR is, the more differences there are. Both methods are interchangeable when analyzing HRV at rest. At high exercise intensity, HRM and PLF still presented a high correlation (ρ > 0.8) and excellent reliability and agreement indices (above 0.9). However, the PHF measurements from the Polar showed reliability and agreement coefficients around 0.5 or lower when the level of the exercise increases (for levels of O2 above 60%).

  14. Achievable Performance of Zero-Delay Variable-Rate Coding in Rate-Constrained Networked Control Systems with Channel Delay

    DEFF Research Database (Denmark)

    Barforooshan, Mohsen; Østergaard, Jan; Stavrou, Fotios

    2017-01-01

    This paper presents an upper bound on the minimum data rate required to achieve a prescribed closed-loop performance level in networked control systems (NCSs). The considered feedback loop includes a linear time-invariant (LTI) plant with single measurement output and single control input. Moreover......, in this NCS, a causal but otherwise unconstrained feedback system carries out zero-delay variable-rate coding, and control. Between the encoder and decoder, data is exchanged over a rate-limited noiseless digital channel with a known constant time delay. Here we propose a linear source-coding scheme...

  15. Perception of male caller identity in Koalas (Phascolarctos cinereus): acoustic analysis and playback experiments.

    Science.gov (United States)

    Charlton, Benjamin D; Ellis, William A H; McKinnon, Allan J; Brumm, Jacqui; Nilsson, Karen; Fitch, W Tecumseh

    2011-01-01

    The ability to signal individual identity using vocal signals and distinguish between conspecifics based on vocal cues is important in several mammal species. Furthermore, it can be important for receivers to differentiate between callers in reproductive contexts. In this study, we used acoustic analyses to determine whether male koala bellows are individually distinctive and to investigate the relative importance of different acoustic features for coding individuality. We then used a habituation-discrimination paradigm to investigate whether koalas discriminate between the bellow vocalisations of different male callers. Our results show that male koala bellows are highly individualized, and indicate that cues related to vocal tract filtering contribute the most to vocal identity. In addition, we found that male and female koalas habituated to the bellows of a specific male showed a significant dishabituation when they were presented with bellows from a novel male. The significant reduction in behavioural response to a final rehabituation playback shows this was not a chance rebound in response levels. Our findings indicate that male koala bellows are highly individually distinctive and that the identity of male callers is functionally relevant to male and female koalas during the breeding season. We go on to discuss the biological relevance of signalling identity in this species' sexual communication and the potential practical implications of our findings for acoustic monitoring of male population levels.

  16. Perception of male caller identity in Koalas (Phascolarctos cinereus: acoustic analysis and playback experiments.

    Directory of Open Access Journals (Sweden)

    Benjamin D Charlton

    Full Text Available The ability to signal individual identity using vocal signals and distinguish between conspecifics based on vocal cues is important in several mammal species. Furthermore, it can be important for receivers to differentiate between callers in reproductive contexts. In this study, we used acoustic analyses to determine whether male koala bellows are individually distinctive and to investigate the relative importance of different acoustic features for coding individuality. We then used a habituation-discrimination paradigm to investigate whether koalas discriminate between the bellow vocalisations of different male callers. Our results show that male koala bellows are highly individualized, and indicate that cues related to vocal tract filtering contribute the most to vocal identity. In addition, we found that male and female koalas habituated to the bellows of a specific male showed a significant dishabituation when they were presented with bellows from a novel male. The significant reduction in behavioural response to a final rehabituation playback shows this was not a chance rebound in response levels. Our findings indicate that male koala bellows are highly individually distinctive and that the identity of male callers is functionally relevant to male and female koalas during the breeding season. We go on to discuss the biological relevance of signalling identity in this species' sexual communication and the potential practical implications of our findings for acoustic monitoring of male population levels.

  17. Heart rate variability in normal-weight patients with polycystic ovary syndrome

    OpenAIRE

    Kilit, Celal; Kilit, T?rkan Pa?al?

    2017-01-01

    Objective: Polycystic ovary syndrome (PCOS) is an endocrine disease closely related to several risk factors of cardiovascular disease. Obese women with PCOS show altered autonomic modulation. The results of studies investigating cardiac autonomic functions of normal-weight women with PCOS are conflicting. The aim of the study was to assess the reactivity of cardiac sympathovagal balance in normal-weight women with PCOS by heart rate variability analysis. Methods: We examined the heart rate va...

  18. Performance evaluation of a newly developed variable rate sprayer for nursery liner applications

    Science.gov (United States)

    An experimental variable-rate sprayer designed for liner applications was tested by comparing its spray deposit, coverage, and droplet density inside canopies of six nursery liner varieties with constant-rate applications. Spray samplers, including water sensitive papers (WSP) and nylon screens, wer...

  19. Improved Bit Rate Control for Real-Time MPEG Watermarking

    Directory of Open Access Journals (Sweden)

    Pranata Sugiri

    2004-01-01

    Full Text Available The alteration of compressed video bitstream due to embedding of digital watermark tends to produce unpredictable video bit rate variations which may in turn lead to video playback buffer overflow/underflow or transmission bandwidth violation problems. This paper presents a novel bit rate control technique for real-time MPEG watermarking applications. In our experiments, spread spectrum watermarks are embedded in the quantized DCT domain without requantization and motion reestimation to achieve fast watermarking. The proposed bit rate control scheme evaluates the combined bit lengths of a set of multiple watermarked VLC codewords, and successively replaces watermarked VLC codewords having the largest increase in bit length with their corresponding unmarked VLC codewords until a target bit length is achieved. The proposed method offers flexibility and scalability, which are neglected by similar works reported in the literature. Experimental results show that the proposed bit rate control scheme is effective in meeting the bit rate targets and capable of improving the watermark detection robustness for different video contents compressed at different bit rates.

  20. Lack of evidence for low-dimensional chaos in heart rate variability

    DEFF Research Database (Denmark)

    Kanters, J K; Holstein-Rathlou, N H; Agner, E

    1994-01-01

    INTRODUCTION: The term chaos is used to describe erratic or apparently random time-dependent behavior in deterministic systems. It has been suggested that the variability observed in the normal heart rate may be due to chaos, but this question has not been settled. METHODS AND RESULTS: Heart rate...... in the experimental data, but the prediction error as a function of the prediction length increased at a slower rate than characteristic of a low-dimensional chaotic system. CONCLUSION: There is no evidence for low-dimensional chaos in the time series of RR intervals from healthy human subjects. However, nonlinear...

  1. Resting and postexercise heart rate variability in professional handball players.

    Science.gov (United States)

    Kayacan, Yildirim; Yildiz, Sedat

    2016-03-01

    The aim of this study was to evaluate heart rate variability (HRV) in professional handball players during rest and following a 5 min mild jogging exercise. For that purpose, electrocardiogram (ECG) of male handball players (N.=12, mean age 25±3.95 years) and sedentary controls (N.=14, mean age 23.5±2.95 years) were recorded for 5 min at rest and just after 5 min of mild jogging. ECGs were recorded and following HRV parameters were calculated: time-domain variables such as heart rate (HR), average normal-to-normal RR intervals, standard deviation of normal-to-normal RR intervals, square root of the mean of the squares of differences between adjacent NN intervals, percentage of differences between adjacent NN intervals that are greater than 50 milliseconds (pNN50), and frequency-domain variables such as very low frequency, low (LF) and high frequency (HF) of the power and LF/HF ratio. Unpaired t-test was used to find out differences among groups while paired t-test was used for comparison of each group for pre- and postjogging HRV. Pearson correlations were carried out to find out the relationships between the parameters. Blood pressures were not different between handball players and sedentary controls but exercise increased systolic blood pressure (Phandball players (Phandball players (Phandball players in response to a mild, short-time (5 min) jogging exercise. However, in sedentary subjects, either the sympathetic regulation of the autonomous nervous system increased or vagal withdrawal occurred.

  2. Do physiological and pathological stresses produce different changes in heart rate variability?

    Directory of Open Access Journals (Sweden)

    Andrea eBravi

    2013-07-01

    Full Text Available Although physiological (e.g. exercise and pathological (e.g. infection stress affecting the cardiovascular system have both been documented to be associated with a reduction in overall heart rate variability (HRV, it remains unclear if loss of HRV is ubiquitously similar across different domains of variability analysis or if distinct patterns of altered HRV exist depending on the stressor. Using Continuous Individualized Multiorgan Variability Analysis (CIMVATM software, heart rate (HR and four selected measures of variability were measured over time (windowed analysis from two datasets, a set (n=13 of patients who developed systemic infection (i.e. sepsis after bone marrow transplant, and a matched set of healthy subjects undergoing physical exercise under controlled conditions. HR and the four HRV measures showed similar trends in both sepsis and exercise. The comparison through Wilcoxon sign-rank test of the levels of variability at baseline and during the stress (i.e. exercise or after days of sepsis development showed similar changes, except for LF/HF, ratio of power at low and high frequencies (associated with sympathovagal modulation, which was affected by exercise but did not show any change during sepsis. Furthermore, HRV measures during sepsis showed a lower level of correlation with each other, as compared to HRV during exercise. In conclusion, this exploratory study highlights similar responses during both exercise and infection, with differences in terms of correlation and inter-subject fluctuations, whose physiologic significance merits further investigation.

  3. Regular Exposure to Cowbells Affects the Behavioral Reactivity to a Noise Stimulus in Dairy Cows

    Directory of Open Access Journals (Sweden)

    Julia Johns

    2017-09-01

    Full Text Available In alpine regions, cows are often equipped with bells during pasture season to ensure that farmers can locate them. Constant exposure to the chime of a bell may affect cows’ acoustic perception in general. The aim of this study is to test whether routine bell exposure affects the reactivity to a noise stimulus and might be associated with hearing impairment in cows. For the assessment, behavioral and cardiac indicators were used as indirect measures of hearing capacity. Cows that were either used to wearing a bell or not were exposed to a playback of low and high amplitude (=varying loudness. In addition, we tested whether wearing earplugs, mimicking hearing impairment, reduced the cows’ reactivity toward the playback. On 24 farms, half of them routinely using cowbells, 96 Brown Swiss cows were tested in a 2 × 2 factorial cross-over design (65 or 85 dB, without or with earplugs in a balanced order. The effects of bell experience, amplitude, and earplugs on the latency to the first behavioral and cardiac response to a 5-s playback were analyzed using linear mixed-effects models, considering dependencies within the data set. Cows reacted faster without earplugs and when they were exposed to 85 dB compared with 65 dB. The proportion of cows leaving the feeding rack after onset of the playback was reduced by bell experience and earplugs and was increased when exposed to 85 dB compared with 65 dB. Exposure without earplugs to 85 dB but not to 65 dB increased heart rate. Heart rate and heart rate variability indicated increased sympathetic activation during the exposure to 85 dB compared with 65 dB. In general, behavioral and cardiac indicators did not indicate severe hearing impairment due to routine bell exposure. The 85-dB stimulus increased arousal and avoidance compared with the 65-dB stimulus, with bell experience and earplugs leading to a general decrease in avoidance of the stimulus. This may reflect an altered

  4. Heart Rate Variability: Effect of Exercise Intensity on Postexercise Response

    Science.gov (United States)

    James, David V. B.; Munson, Steven C.; Maldonado-Martin, Sara; De Ste Croix, Mark B. A.

    2012-01-01

    The purpose of the present study was to investigate the influence of two exercise intensities (moderate and severe) on heart rate variability (HRV) response in 16 runners 1 hr prior to (-1 hr) and at +1 hr, +24 hr, +48 hr, and +72 hr following each exercise session. Time domain indexes and a high frequency component showed a significant decrease…

  5. Bounds on Rates of Variable-Basis and Neural-Network Approximation

    Czech Academy of Sciences Publication Activity Database

    Kůrková, Věra; Sanguineti, M.

    2001-01-01

    Roč. 47, č. 6 (2001), s. 2659-2665 ISSN 0018-9448 R&D Projects: GA ČR GA201/00/1482 Institutional research plan: AV0Z1030915 Keywords : approximation by variable-basis functions * bounds on rates of approximation * complexity of neural networks * high-dimensional optimal decision problems Subject RIV: BA - General Mathematics Impact factor: 2.077, year: 2001

  6. Heart rate variability analysis in acute poisoning by cholinesterase inhibitors

    OpenAIRE

    JEONG, JINWOO; KIM, YONGIN

    2017-01-01

    Heart rate variability (HRV) has been associated with a variety of clinical situations. However, few studies have examined the association between HRV and acute poisoning. Organophosphate (OP) and carbamate inhibit esterase enzymes, particularly acetylcholinesterase, resulting in an accumulation of acetylcholine and thereby promoting excessive activation of corresponding receptors. Because diagnosis and treatment of OP and carbamate poisoning greatly depend on...

  7. Modeling Short-Range Soil Variability and its Potential Use in Variable-Rate Treatment of Experimental Plots

    Directory of Open Access Journals (Sweden)

    A Moameni

    2011-02-01

    Full Text Available Abstract In Iran, the experimental plots under fertilizer trials are managed in such a way that the whole plot area uniformly receives agricultural inputs. This could lead to biased research results and hence to suppressing of the efforts made by the researchers. This research was conducted in a selected site belonging to the Gonbad Agricultural Research Station, located in the semiarid region, northeastern Iran. The aim was to characterize the short-range spatial variability of the inherent and management-depended soil properties and to determine if this variation is large and can be managed at practical scales. The soils were sampled using a grid 55 m apart. In total, 100 composite soil samples were collected from topsoil (0-30 cm and were analyzed for calcium carbonate equivalent, organic carbon, clay, available phosphorus, available potassium, iron, copper, zinc and manganese. Descriptive statistics were applied to check data trends. Geostatistical analysis was applied to variography, model fitting and contour mapping. Sampling at 55 m made it possible to split the area of the selected experimental plot into relatively uniform areas that allow application of agricultural inputs with variable rates. Keywords: Short-range soil variability, Within-field soil variability, Interpolation, Precision agriculture, Geostatistics

  8. Nonlinear analysis of heart rate variability in patients with eating disorders

    NARCIS (Netherlands)

    Vigo, Daniel E.; Castro, Mariana N.; Dorpinghaus, Andrea; Weidema, Hylke; Cardinali, Daniel P.; Siri, Leonardo Nicola; Rovira, Bernardo; Fahrer, Rodolfo D.; Nogues, Martin; Leiguarda, Ramon C.; Guinjoan, Salvador M.

    2008-01-01

    Patients with anorexia nervosa or bulimia nervosa often have signs of autonomic dysfunction potentially deleterious to the heart. The aim of this study was to ascertain the nonlinear properties of heart rate variability in patients with eating disorders. A group of 33 women with eating disorders (14

  9. Heart rate variability biofeedback improves cardiorespiratory resting function during sleep.

    Science.gov (United States)

    Sakakibara, Masahito; Hayano, Junichiro; Oikawa, Leo O; Katsamanis, Maria; Lehrer, Paul

    2013-12-01

    The present study was designed to examine the effect of heart rate variability (HRV) biofeedback on the cardiorespiratory resting function during sleep in daily life. Forty-five healthy young adults were randomly assigned to one of three groups: HRV biofeedback, Autogenic Training(AT), and no-treatment control. Participants in the HRV biofeedback were instructed to use a handheld HRV biofeedback device before their habitual bedtime, those in the AT were asked to listen to an audiotaped instruction before bedtime,and those in the control were asked to engage in their habitual activity before bedtime. Pulse wave signal during sleep at their own residences was measured continuously with a wrist watch-type transdermal photoelectric sensor for three time points. Baseline data were collected on the first night of measurements, followed by two successive nights for HRV biofeedback, AT, or control. Cardiorespiratory resting function was assessed quantitatively as the amplitude of high frequency(HF) component of pulse rate variability, a surrogate measure of respiratory sinus arrhythmia. HF component increased during sleep in the HRV biofeedback group,although it remained unchanged in the AT and control groups. These results suggest that HRV biofeedback before sleep may improve cardiorespiratory resting function during sleep.

  10. Influence of heavy cigarette smoking on heart rate variability and heart rate turbulence parameters

    DEFF Research Database (Denmark)

    Cagirci, Goksel; Cay, Serkan; Karakurt, Ozlem

    2009-01-01

    BACKGROUND: Cigarette smoking increases the risk of cardiovascular events related with several mechanisms. The most suggested mechanism is increased activity of sympathetic nervous system. Heart rate variability (HRV) and heart rate turbulence (HRT) has been shown to be independent and powerful......, 69 subjects and nonsmokers 74 subjects (control group) were enrolled in this study. HRV and HRT analyses [turbulence onset (TO) and turbulence slope (TS)] were assessed from 24-hour Holter recordings. RESULTS: The values of TO were significantly higher in heavy cigarette smokers than control group...... (-1.150 +/- 4.007 vs -2.454 +/- 2.796, P = 0.025, respectively), but values of TS were not statistically different between two groups (10.352 +/- 7.670 vs 9.613 +/- 7.245, P = 0.555, respectively). Also, the number of patients who had abnormal TO was significantly higher in heavy cigarette smokers...

  11. Metaiodobenzylguanidine and heart rate variability in heart failure

    International Nuclear Information System (INIS)

    Kurata, Chinori; Shouda, Sakae; Mikami, Tadashi; Uehara, Akihiko; Ishikawa, Keiko; Tawarahara, Kei; Nakano, Tomoyasu; Matoh, Fumitaka; Takeuchi, Kazuhiko

    1998-01-01

    It is assumed that the low-frequency power (LF) of heart rate variability (HRV) increases with progress of congestive heart failure (CHF), therefore positively correlating with cardiac 123 I-metaiodobenzylguanidine (MIBG) washout. It is demonstrated here that HRV, including normalized LF, correlated inversely with MIBG washout and positively with the ratio of heart-to-mediastinum MIBG activity in controls and CHF patients, whereas these correlations were not observed within CHF patients. Thus MIBG washout may increase and HRV including normalized LF may decrease with CHF, although the HRV and MIBG measures may not similarly change in proportion to the severity of the cardiac autonomic dysfunction in CHF. (author)

  12. Metaiodobenzylguanidine and heart rate variability in heart failure

    Energy Technology Data Exchange (ETDEWEB)

    Kurata, Chinori; Shouda, Sakae; Mikami, Tadashi; Uehara, Akihiko; Ishikawa, Keiko [Hamamatsu Univ., Shizuoka (Japan). School of Medicine; Tawarahara, Kei; Nakano, Tomoyasu; Matoh, Fumitaka; Takeuchi, Kazuhiko

    1998-10-01

    It is assumed that the low-frequency power (LF) of heart rate variability (HRV) increases with progress of congestive heart failure (CHF), therefore positively correlating with cardiac {sup 123}I-metaiodobenzylguanidine (MIBG) washout. It is demonstrated here that HRV, including normalized LF, correlated inversely with MIBG washout and positively with the ratio of heart-to-mediastinum MIBG activity in controls and CHF patients, whereas these correlations were not observed within CHF patients. Thus MIBG washout may increase and HRV including normalized LF may decrease with CHF, although the HRV and MIBG measures may not similarly change in proportion to the severity of the cardiac autonomic dysfunction in CHF. (author)

  13. Students' Ways of Thinking about Two-Variable Functions and Rate of Change in Space

    Science.gov (United States)

    Weber, Eric David

    2012-01-01

    This dissertation describes an investigation of four students' ways of thinking about functions of two variables and rate of change of those two-variable functions. Most secondary, introductory algebra, pre-calculus, and first and second semester calculus courses do not require students to think about functions of more than one variable. Yet…

  14. Results of Propellant Mixing Variable Study Using Precise Pressure-Based Burn Rate Calculations

    Science.gov (United States)

    Stefanski, Philip L.

    2014-01-01

    A designed experiment was conducted in which three mix processing variables (pre-curative addition mix temperature, pre-curative addition mixing time, and mixer speed) were varied to estimate their effects on within-mix propellant burn rate variability. The chosen discriminator for the experiment was the 2-inch diameter by 4-inch long (2x4) Center-Perforated (CP) ballistic evaluation motor. Motor nozzle throat diameters were sized to produce a common targeted chamber pressure. Initial data analysis did not show a statistically significant effect. Because propellant burn rate must be directly related to chamber pressure, a method was developed that showed statistically significant effects on chamber pressure (either maximum or average) by adjustments to the process settings. Burn rates were calculated from chamber pressures and these were then normalized to a common pressure for comparative purposes. The pressure-based method of burn rate determination showed significant reduction in error when compared to results obtained from the Brooks' modification of the propellant web-bisector burn rate determination method. Analysis of effects using burn rates calculated by the pressure-based method showed a significant correlation of within-mix burn rate dispersion to mixing duration and the quadratic of mixing duration. The findings were confirmed in a series of mixes that examined the effects of mixing time on burn rate variation, which yielded the same results.

  15. Validation of a new control system for Elekta accelerators facilitating continuously variable dose rate

    DEFF Research Database (Denmark)

    Bertelsen, Anders; Lorenzen, Ebbe L; Brink, Carsten

    2011-01-01

    ) as well as BVDR. Using CVDR opposed to BVDR for VMAT has the potential of reducing the treatment time but may lead to lower dosimetric accuracy due to faster moving accelerator parts. Using D7 and a test version of Integrity, differences in ability to control the accelerator, treatment efficiency......Elekta accelerators controlled by the current clinically used accelerator control system, Desktop 7.01 (D7), uses binned variable dose rate (BVDR) for volumetric modulated arc therapy (VMAT). The next version of the treatment control system (Integrity) supports continuously variable dose rate (CVDR...

  16. Reproducibility of heart rate variability, blood pressure variability and baroreceptor sensitivity during rest and head-up tilt

    DEFF Research Database (Denmark)

    Højgaard, Michael V; Agner, Erik; Kanters, Jørgen K

    2005-01-01

    OBJECTIVE: Previous studies have indicated moderate-to-poor reproducibility of heart rate variability (HRV) but the reproducibility of blood pressure variability (BPV) and spectral measures of baroreceptor sensitivity (BRS) are not well established. METHODS: We measured normal-to-normal heart beat...... pressures were extracted for the assessment of day-to-day and short-term reproducibility. Power spectrum analysis (Fourier) and transfer function analysis was performed. Reproducibility was assessed using the coefficient of variation (CV). The reproducibility of the mean RR interval, mean systolic......, diastolic and mean blood pressure was good (CVspectral parameters of HRV (CV range 18-36%) and BPV (16-44%) and moderate reproducibility of BRS (14-20%). CONCLUSION: Spectral estimates of BRS had only moderate reproducibility although...

  17. Heart rate and heart rate variability modification in chronic insomnia patients.

    Science.gov (United States)

    Farina, Benedetto; Dittoni, Serena; Colicchio, Salvatore; Testani, Elisa; Losurdo, Anna; Gnoni, Valentina; Di Blasi, Chiara; Brunetti, Riccardo; Contardi, Anna; Mazza, Salvatore; Della Marca, Giacomo

    2014-01-01

    Chronic insomnia is highly prevalent in the general population, provoking personal distress and increased risk for psychiatric and medical disorders. Autonomic hyper-arousal could be a pathogenic mechanism of chronic primary insomnia. The aim of this study was to investigate autonomic activity in patients with chronic primary insomnia by means of heart rate variability (HRV) analysis. Eighty-five consecutive patients affected by chronic primary insomnia were enrolled (38 men and 47 women; mean age: 53.2 ± 13.6). Patients were compared with a control group composed of 55 healthy participants matched for age and gender (23 men and 32 women; mean age: 54.2 ± 13.9). Patients underwent an insomnia study protocol that included subjective sleep evaluation, psychometric measures, and home-based polysomnography with evaluation of HRV in wake before sleep, in all sleep stages, and in wake after final awakening. Patients showed modifications of heart rate and HRV parameters, consistent with increased sympathetic activity, while awake before sleep and during Stage-2 non-REM sleep. No significant differences between insomniacs and controls could be detected during slow-wave sleep, REM sleep, and post-sleep wake. These results are consistent with the hypothesis that autonomic hyper-arousal is a major pathogenic mechanism in primary insomnia, and confirm that this condition is associated with an increased cardiovascular risk.

  18. Respiratory induced heart rate variability during slow mechanical ventilation Marker to exclude brain death patients

    Czech Academy of Sciences Publication Activity Database

    Jurák, Pavel; Halámek, Josef; Vondra, Vlastimil; Kružliak, P.; Šrámek, V.; Cundrle, I.; Leinveber, P.; Adamek, M.; Zvoníček, V.

    2017-01-01

    Roč. 129, 7-8 (2017), s. 251-258 ISSN 0043-5325 R&D Projects: GA ČR GAP103/11/0933; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01; GA MZd NS10105 Institutional support: RVO:68081731 Keywords : critical illness * sedation * brain death * respiratory rate variability * heart rate variability * mechanical ventilation Subject RIV: FS - Medical Facilities ; Equipment OBOR OECD: Medical engineering Impact factor: 0.974, year: 2016

  19. Heart Rate Variability as a Measure of Airport Ramp-Traffic Controllers Workload

    Science.gov (United States)

    Hayashi, Miwa; Dulchinos, Victoria Lee

    2016-01-01

    Heart Rate Variability (HRV) has been reported to reflect the person's cognitive and emotional stress levels, and may offer an objective measure of human-operator's workload levels, which are recorded continuously and unobtrusively to the task performance. The present paper compares the HRV data collected during a human-in-the-loop simulation of airport ramp-traffic control operations with the controller participants' own verbal self-reporting ratings of their workload.

  20. Factors that affect the variability in heart rate during endoscopic retrograde cholangiopancreatography

    DEFF Research Database (Denmark)

    Christensen, Merete; Reinert, Rebekka; Rasmussen, Verner

    2002-01-01

    OBJECTIVE: To find out if drugs, position, and endoscopic manipulation during endoscopic retrograde cholangiopancreatography (ERCP) influence the changes in the variability of heart rate. DESIGN: Single-blind randomised trial. SUBJECTS: 10 volunteers given butyscopolamine, glucagon, or saline...

  1. HEART RATE VARIABILITY CLASSIFICATION USING SADE-ELM CLASSIFIER WITH BAT FEATURE SELECTION

    Directory of Open Access Journals (Sweden)

    R Kavitha

    2017-07-01

    Full Text Available The electrical activity of the human heart is measured by the vital bio medical signal called ECG. This electrocardiogram is employed as a crucial source to gather the diagnostic information of a patient’s cardiopathy. The monitoring function of cardiac disease is diagnosed by documenting and handling the electrocardiogram (ECG impulses. In the recent years many research has been done and developing an enhanced method to identify the risk in the patient’s body condition by processing and analysing the ECG signal. This analysis of the signal helps to find the cardiac abnormalities, arrhythmias, and many other heart problems. ECG signal is processed to detect the variability in heart rhythm; heart rate variability is calculated based on the time interval between heart beats. Heart Rate Variability HRV is measured by the variation in the beat to beat interval. The Heart rate Variability (HRV is an essential aspect to diagnose the properties of the heart. Recent development enhances the potential with the aid of non-linear metrics in reference point with feature selection. In this paper, the fundamental elements are taken from the ECG signal for feature selection process where Bat algorithm is employed for feature selection to predict the best feature and presented to the classifier for accurate classification. The popular machine learning algorithm ELM is taken for classification, integrated with evolutionary algorithm named Self- Adaptive Differential Evolution Extreme Learning Machine SADEELM to improve the reliability of classification. It combines Effective Fuzzy Kohonen clustering network (EFKCN to be able to increase the accuracy of the effect for HRV transmission classification. Hence, it is observed that the experiment carried out unveils that the precision is improved by the SADE-ELM method and concurrently optimizes the computation time.

  2. Heart rate variability alters cardiac repolarization and electromechanical dynamics.

    Science.gov (United States)

    Phadumdeo, Vrishti M; Weinberg, Seth H

    2018-04-07

    Heart rate continuously varies due to autonomic regulation, stochasticity in pacemaking, and circadian rhythm, collectively termed heart rate variability (HRV), during normal physiological conditions. Low HRV is clinically associated with an elevated risk of cardiac arrhythmias. Alternans, a beat-to-beat alternation in action potential duration (APD) and/or intracellular calcium (Ca) transient, is a well-known risk factor associated with cardiac arrhythmias that is typically studied under conditions of a constant pacing rate, i.e., the absence of HRV. In this study, we investigate the effects of HRV on the interplay between APD, Ca, and electromechanical properties, employing a nonlinear discrete-time map model that governs APD and intracellular Ca cycling with a stochastic pacing period. We find that HRV can decrease variation in APD and peak Ca at fast pacing rates for which alternans is present. Further, increased HRV typically disrupts the alternating pattern for both APD and peak Ca and weakens the correlation between APD and peak Ca, thus decoupling Ca-mediated instabilities from repolarization alternation. We find that the efficacy of these effects is regulated by the sarcoplasmic reticulum Ca uptake rate. Overall, these results demonstrate that HRV disrupts arrhythmogenic alternans and suggests that HRV may be a significant factor in preventing life-threatening arrhythmias. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Tempts to determine radon entry rate and air exchange rate variable in time from the time course of indoor radon concentration

    International Nuclear Information System (INIS)

    Thomas, J.

    1996-01-01

    For the study and explanation of the diurnal variability of the indoor radon concentration a(t) [Bq/m 3 ], which is proportional to the ratio of the radon entry rate A [Bq/h] and the air exchange rate k [1/h], it would be of advantage to know separately the diurnal variability of both determining quantities A(t) and k(t). To measure directly and continuously the radon entry rate A(t) is possible only in special studies (mostly in experimental rooms) and also continuous measuring of the air exchange rate k(t) is possible also only in special studies for a short time. But continuously measuring radon meters are now common, do not trouble people in normal living regime during day and night. The goal of this endeavour would be the evaluation of the time courses of both determining quantities from the time courses of the indoor radon concentration directly without additional experimental work and so a better utilisation of such measurements. (author)

  4. Diminution of Heart Rate Variability in Bipolar Depression

    Directory of Open Access Journals (Sweden)

    Brandon Hage

    2017-12-01

    Full Text Available Autonomic nervous system (ANS dysregulation in depression is associated with symptoms associated with the ANS. The beat-to-beat pattern of heart rate defined as heart rate variability (HRV provides a noninvasive portal to ANS function and has been proposed to represent a means of quantifying resting vagal tone. We quantified HRV in bipolar depressed (BDD patients as a measure of ANS dysregulation seeking to establish HRV as a potential diagnostic and prognostic biomarker for treatment outcome. Forty-seven BDD patients were enrolled. They were randomized to receive either escitalopram–celecoxib or escitalopram-placebo over 8 weeks in a double-blind study design. Thirty-five patients completed the HRV studies. Thirty-six healthy subjects served as controls. HRV was assessed at pretreatment and end of study and compared with that of controls. HRV was quantified and corrected for artifacts using an algorithm that incorporates time and frequency domains to address non-stationarity of the beat-to-beat heart rate pattern. Baseline high frequency-HRV (i.e., respiratory sinus arrhythmia was lower in BDD patients than controls, although the difference did not reach significance. Baseline low-frequency HRV was significantly lower in BDD patients (ln4.20 than controls (ln = 5.50 (p < 0.01. Baseline heart period was significantly shorter (i.e., faster heart rate in BDD patients than controls. No significant change in HRV parameters were detected over the course of the study with either treatment. These findings suggest that components of HRV may be diminished in BDD patients.

  5. Stimulus variability and the phonetic relevance hypothesis: effects of variability in speaking style, fundamental frequency, and speaking rate on spoken word identification.

    Science.gov (United States)

    Sommers, Mitchell S; Barcroft, Joe

    2006-04-01

    Three experiments were conducted to examine the effects of trial-to-trial variations in speaking style, fundamental frequency, and speaking rate on identification of spoken words. In addition, the experiments investigated whether any effects of stimulus variability would be modulated by phonetic confusability (i.e., lexical difficulty). In Experiment 1, trial-to-trial variations in speaking style reduced the overall identification performance compared with conditions containing no speaking-style variability. In addition, the effects of variability were greater for phonetically confusable words than for phonetically distinct words. In Experiment 2, variations in fundamental frequency were found to have no significant effects on spoken word identification and did not interact with lexical difficulty. In Experiment 3, two different methods for varying speaking rate were found to have equivalent negative effects on spoken word recognition and similar interactions with lexical difficulty. Overall, the findings are consistent with a phonetic-relevance hypothesis, in which accommodating sources of acoustic-phonetic variability that affect phonetically relevant properties of speech signals can impair spoken word identification. In contrast, variability in parameters of the speech signal that do not affect phonetically relevant properties are not expected to affect overall identification performance. Implications of these findings for the nature and development of lexical representations are discussed.

  6. Heart rate variability: a tool to explore the sleeping brain?

    OpenAIRE

    Chouchou, Florian; Desseilles, Martin

    2014-01-01

    Sleep is divided into two main sleep stages: (1) non-rapid eye movement sleep (non-REMS), characterized among others by reduced global brain activity; and (2) rapid eye movement sleep (REMS), characterized by global brain activity similar to that of wakefulness. Results of heart rate variability (HRV) analysis, which is widely used to explore autonomic modulation, have revealed higher parasympathetic tone during normal non-REMS and a shift toward sympathetic predominance during normal REMS. M...

  7. Variability of Basal Rate Profiles in Insulin Pump Therapy and Association with Complications in Type 1 Diabetes Mellitus.

    Science.gov (United States)

    Laimer, Markus; Melmer, Andreas; Mader, Julia K; Schütz-Fuhrmann, Ingrid; Engels, Heide-Rose; Götz, Gabriele; Pfeifer, Martin; Hermann, Julia M; Stettler, Christoph; Holl, Reinhard W

    2016-01-01

    Traditionally, basal rate profiles in continuous subcutaneous insulin infusion therapy are individually adapted to cover expected insulin requirements. However, whether this approach is indeed superior to a more constant BR profile has not been assessed so far. This study analysed the associations between variability of BR profiles and acute and chronic complications in adult type 1 diabetes mellitus. BR profiles of 3118 female and 2427 male patients from the "Diabetes-Patienten-Verlaufsdokumentation" registry from Germany and Austria were analysed. Acute and chronic complications were recorded 6 months prior and after the most recently documented basal rate. The "variability index" was calculated as variation of basal rate intervals in percent and describes the excursions of the basal rate intervals from the median basal rate. The variability Index correlated positively with severe hypoglycemia (r = .06; p1), hypoglycemic coma (r = .05; p = 0.002), and microalbuminuria (r = 0.05; p = 0.006). In addition, a higher variability index was associated with higher frequency of diabetic ketoacidosis (r = .04; p = 0.029) in male adult patients. Logistic regression analysis adjusted for age, gender, duration of disease and total basal insulin confirmed significant correlations of the variability index with severe hypoglycemia (β = 0.013; p1) and diabetic ketoacidosis (β = 0.012; p = 0.017). Basal rate profiles with higher variability are associated with an increased frequency of acute complications in adults with type 1 diabetes.

  8. Air pollution and heart rate variability: effect modification by chronic lead exposure.

    Science.gov (United States)

    Park, Sung Kyun; O'Neill, Marie S; Vokonas, Pantel S; Sparrow, David; Wright, Robert O; Coull, Brent; Nie, Huiling; Hu, Howard; Schwartz, Joel

    2008-01-01

    Outdoor air pollution and lead exposure can disturb cardiac autonomic function, but the effects of both these exposures together have not been studied. We examined whether higher cumulative lead exposures, as measured by bone lead, modified cross-sectional associations between air pollution and heart rate variability among 384 elderly men from the Normative Aging Study. We used linear regression, controlling for clinical, demographic, and environmental covariates. We found graded, significant reductions in both high-frequency and low-frequency powers of heart rate variability in relation to ozone and sulfate across the quartiles of tibia lead. Interquartile range increases in ozone and sulfate were associated respectively, with 38% decrease (95% confidence interval = -54.6% to -14.9%) and 22% decrease (-40.4% to 1.6%) in high frequency, and 38% decrease (-51.9% to -20.4%) and 12% decrease (-28.6% to 9.3%) in low frequency, in the highest quartile of tibia lead after controlling for potential confounders. We observed similar but weaker effect modification by tibia lead adjusted for education and cumulative traffic (residuals of the regression of tibia lead on education and cumulative traffic). Patella lead modified only the ozone effect on heart rate variability. People with long-term exposure to higher levels of lead may be more sensitive to cardiac autonomic dysfunction on high air pollution days. Efforts to understand how environmental exposures affect the health of an aging population should consider both current levels of pollution and history of lead exposure as susceptibility factors.

  9. A single dose of dark chocolate increases parasympathetic modulation and heart rate variability in healthy subjects

    Directory of Open Access Journals (Sweden)

    Ana Amélia Machado DUARTE

    Full Text Available ABSTRACT Objective: The aim of this study was to investigate the acute effect of a single dose of dark chocolate (70% cocoa on blood pressure and heart rate variability. Methods: Thirty-one healthy subjects (aged 18-25 years; both sexes were divided into two groups: 10 subjects in the white chocolate (7.4 g group and 21 in the dark chocolate (10 g group; measurements were performed at the university's physiology lab. An electrocardiogram measured the sympathovagal balance by spectral and symbolic analysis. Results: A single dose of dark chocolate significantly reduced systolic blood pressure and heart rate. After consuming 10 g of dark chocolate, significant increases were observed for heart rate variability, standard deviation of RR intervals standard deviation of all NN intervals, square root of the mean squared differences between adjacent normal RR intervals root mean square of successive differences, and an increase in the high frequency component in absolute values, representing the parasympathetic modulation. Conclusion: In conclusion the importance of our results lies in the magnitude of the response provoked by a single dose of cocoa. Just 10 g of cocoa triggered a significant increase in parasympathetic modulation and heart rate variability. These combined effects can potentially increase life expectancy because a reduction in heart rate variability is associated with several cardiovascular diseases and higher mortality.

  10. Electrocardiogram application based on heart rate variability ontology and fuzzy markup language

    NARCIS (Netherlands)

    Wang, M.-H.; Lee, C.-S.; Acampora, G.; Loia, V.; Gacek, A.; Pedrycz, W.

    2011-01-01

    The electrocardiogram (ECG) signal is adopted extensively as a low-cost diagnostic procedure to provide information concerning the healthy status of the heart. Heart rate variability (HRV) is a physiological phenomenon where the time interval between heart beats varies. It is measured by the

  11. Feasibility, Reliability and Predictive Value Of In-Ambulance Heart Rate Variability Registration

    NARCIS (Netherlands)

    Yperzeele, Laetitia; van Hooff, Robbert-Jan; De Smedt, Ann; Nagels, Guy; Hubloue, Ives; De Keyser, Jacques; Brouns, Raf

    2016-01-01

    Background Heart rate variability (HRV) is a parameter of autonomic nervous system function. A decrease of HRV has been associated with disease severity, risk of complications and prognosis in several conditions. Objective We aim to investigate the feasibility and the reliability of in-ambulance HRV

  12. A Configurable Event-Driven Convolutional Node with Rate Saturation Mechanism for Modular ConvNet Systems Implementation

    Science.gov (United States)

    Camuñas-Mesa, Luis A.; Domínguez-Cordero, Yaisel L.; Linares-Barranco, Alejandro; Serrano-Gotarredona, Teresa; Linares-Barranco, Bernabé

    2018-01-01

    Convolutional Neural Networks (ConvNets) are a particular type of neural network often used for many applications like image recognition, video analysis or natural language processing. They are inspired by the human brain, following a specific organization of the connectivity pattern between layers of neurons known as receptive field. These networks have been traditionally implemented in software, but they are becoming more computationally expensive as they scale up, having limitations for real-time processing of high-speed stimuli. On the other hand, hardware implementations show difficulties to be used for different applications, due to their reduced flexibility. In this paper, we propose a fully configurable event-driven convolutional node with rate saturation mechanism that can be used to implement arbitrary ConvNets on FPGAs. This node includes a convolutional processing unit and a routing element which allows to build large 2D arrays where any multilayer structure can be implemented. The rate saturation mechanism emulates the refractory behavior in biological neurons, guaranteeing a minimum separation in time between consecutive events. A 4-layer ConvNet with 22 convolutional nodes trained for poker card symbol recognition has been implemented in a Spartan6 FPGA. This network has been tested with a stimulus where 40 poker cards were observed by a Dynamic Vision Sensor (DVS) in 1 s time. Different slow-down factors were applied to characterize the behavior of the system for high speed processing. For slow stimulus play-back, a 96% recognition rate is obtained with a power consumption of 0.85 mW. At maximum play-back speed, a traffic control mechanism downsamples the input stimulus, obtaining a recognition rate above 63% when less than 20% of the input events are processed, demonstrating the robustness of the network. PMID:29515349

  13. A Configurable Event-Driven Convolutional Node with Rate Saturation Mechanism for Modular ConvNet Systems Implementation

    Directory of Open Access Journals (Sweden)

    Luis A. Camuñas-Mesa

    2018-02-01

    Full Text Available Convolutional Neural Networks (ConvNets are a particular type of neural network often used for many applications like image recognition, video analysis or natural language processing. They are inspired by the human brain, following a specific organization of the connectivity pattern between layers of neurons known as receptive field. These networks have been traditionally implemented in software, but they are becoming more computationally expensive as they scale up, having limitations for real-time processing of high-speed stimuli. On the other hand, hardware implementations show difficulties to be used for different applications, due to their reduced flexibility. In this paper, we propose a fully configurable event-driven convolutional node with rate saturation mechanism that can be used to implement arbitrary ConvNets on FPGAs. This node includes a convolutional processing unit and a routing element which allows to build large 2D arrays where any multilayer structure can be implemented. The rate saturation mechanism emulates the refractory behavior in biological neurons, guaranteeing a minimum separation in time between consecutive events. A 4-layer ConvNet with 22 convolutional nodes trained for poker card symbol recognition has been implemented in a Spartan6 FPGA. This network has been tested with a stimulus where 40 poker cards were observed by a Dynamic Vision Sensor (DVS in 1 s time. Different slow-down factors were applied to characterize the behavior of the system for high speed processing. For slow stimulus play-back, a 96% recognition rate is obtained with a power consumption of 0.85 mW. At maximum play-back speed, a traffic control mechanism downsamples the input stimulus, obtaining a recognition rate above 63% when less than 20% of the input events are processed, demonstrating the robustness of the network.

  14. A Configurable Event-Driven Convolutional Node with Rate Saturation Mechanism for Modular ConvNet Systems Implementation.

    Science.gov (United States)

    Camuñas-Mesa, Luis A; Domínguez-Cordero, Yaisel L; Linares-Barranco, Alejandro; Serrano-Gotarredona, Teresa; Linares-Barranco, Bernabé

    2018-01-01

    Convolutional Neural Networks (ConvNets) are a particular type of neural network often used for many applications like image recognition, video analysis or natural language processing. They are inspired by the human brain, following a specific organization of the connectivity pattern between layers of neurons known as receptive field. These networks have been traditionally implemented in software, but they are becoming more computationally expensive as they scale up, having limitations for real-time processing of high-speed stimuli. On the other hand, hardware implementations show difficulties to be used for different applications, due to their reduced flexibility. In this paper, we propose a fully configurable event-driven convolutional node with rate saturation mechanism that can be used to implement arbitrary ConvNets on FPGAs. This node includes a convolutional processing unit and a routing element which allows to build large 2D arrays where any multilayer structure can be implemented. The rate saturation mechanism emulates the refractory behavior in biological neurons, guaranteeing a minimum separation in time between consecutive events. A 4-layer ConvNet with 22 convolutional nodes trained for poker card symbol recognition has been implemented in a Spartan6 FPGA. This network has been tested with a stimulus where 40 poker cards were observed by a Dynamic Vision Sensor (DVS) in 1 s time. Different slow-down factors were applied to characterize the behavior of the system for high speed processing. For slow stimulus play-back, a 96% recognition rate is obtained with a power consumption of 0.85 mW. At maximum play-back speed, a traffic control mechanism downsamples the input stimulus, obtaining a recognition rate above 63% when less than 20% of the input events are processed, demonstrating the robustness of the network.

  15. The effects of auditory stimulation with music on heart rate variability in healthy women

    Directory of Open Access Journals (Sweden)

    Adriano L. Roque

    2013-07-01

    Full Text Available OBJECTIVES: There are no data in the literature with regard to the acute effects of different styles of music on the geometric indices of heart rate variability. In this study, we evaluated the acute effects of relaxant baroque and excitatory heavy metal music on the geometric indices of heart rate variability in women. METHODS: We conducted this study in 21 healthy women ranging in age from 18 to 35 years. We excluded persons with previous experience with musical instruments and persons who had an affinity for the song styles. We evaluated two groups: Group 1 (n = 21, who were exposed to relaxant classical baroque musical and excitatory heavy metal auditory stimulation; and Group 2 (n = 19, who were exposed to both styles of music and white noise auditory stimulation. Using earphones, the volunteers were exposed to baroque or heavy metal music for five minutes. After the first music exposure to baroque or heavy metal music, they remained at rest for five minutes; subsequently, they were re-exposed to the opposite music (70-80 dB. A different group of women were exposed to the same music styles plus white noise auditory stimulation (90 dB. The sequence of the songs was randomized for each individual. We analyzed the following indices: triangular index, triangular interpolation of RR intervals and Poincaré plot (standard deviation of instantaneous beat-by-beat variability, standard deviation of the long-term RR interval, standard deviation of instantaneous beat-by-beat variability and standard deviation of the long-term RR interval ratio, low frequency, high frequency, low frequency/high frequency ratio, standard deviation of all the normal RR intervals, root-mean square of differences between the adjacent normal RR intervals and the percentage of adjacent RR intervals with a difference of duration greater than 50 ms. Heart rate variability was recorded at rest for 10 minutes. RESULTS: The triangular index and the standard deviation of

  16. The effects of auditory stimulation with music on heart rate variability in healthy women.

    Science.gov (United States)

    Roque, Adriano L; Valenti, Vitor E; Guida, Heraldo L; Campos, Mônica F; Knap, André; Vanderlei, Luiz Carlos M; Ferreira, Lucas L; Ferreira, Celso; Abreu, Luiz Carlos de

    2013-07-01

    There are no data in the literature with regard to the acute effects of different styles of music on the geometric indices of heart rate variability. In this study, we evaluated the acute effects of relaxant baroque and excitatory heavy metal music on the geometric indices of heart rate variability in women. We conducted this study in 21 healthy women ranging in age from 18 to 35 years. We excluded persons with previous experience with musical instruments and persons who had an affinity for the song styles. We evaluated two groups: Group 1 (n = 21), who were exposed to relaxant classical baroque musical and excitatory heavy metal auditory stimulation; and Group 2 (n = 19), who were exposed to both styles of music and white noise auditory stimulation. Using earphones, the volunteers were exposed to baroque or heavy metal music for five minutes. After the first music exposure to baroque or heavy metal music, they remained at rest for five minutes; subsequently, they were re-exposed to the opposite music (70-80 dB). A different group of women were exposed to the same music styles plus white noise auditory stimulation (90 dB). The sequence of the songs was randomized for each individual. We analyzed the following indices: triangular index, triangular interpolation of RR intervals and Poincaré plot (standard deviation of instantaneous beat-by-beat variability, standard deviation of the long-term RR interval, standard deviation of instantaneous beat-by-beat variability and standard deviation of the long-term RR interval ratio), low frequency, high frequency, low frequency/high frequency ratio, standard deviation of all the normal RR intervals, root-mean square of differences between the adjacent normal RR intervals and the percentage of adjacent RR intervals with a difference of duration greater than 50 ms. Heart rate variability was recorded at rest for 10 minutes. The triangular index and the standard deviation of the long-term RR interval indices were reduced

  17. Effects of metronome breathing on the assessment of autonomic control using heart rate variability

    NARCIS (Netherlands)

    Haaksma, J; Brouwer, J; vandenBerg, MP; Dijk, WA; Dassen, WRM; Crijns, HJGM; Mulder, Lambertus; Mulder, Gysbertus

    1996-01-01

    Analysis of Heart Rate Variability is a non-invasive quantitative tool to study the influence of the autonomic nervous system on the heart. Rapid variations in heart rate, related to breathing are primarily mediated by the vagal limb of the autonomic nervous system. The resulting variations in heart

  18. Sounds scary? Lack of habituation following the presentation of novel sounds.

    Directory of Open Access Journals (Sweden)

    Tine A Biedenweg

    Full Text Available BACKGROUND: Animals typically show less habituation to biologically meaningful sounds than to novel signals. We might therefore expect that acoustic deterrents should be based on natural sounds. METHODOLOGY: We investigated responses by western grey kangaroos (Macropus fulignosus towards playback of natural sounds (alarm foot stomps and Australian raven (Corvus coronoides calls and artificial sounds (faux snake hiss and bull whip crack. We then increased rate of presentation to examine whether animals would habituate. Finally, we varied frequency of playback to investigate optimal rates of delivery. PRINCIPAL FINDINGS: Nine behaviors clustered into five Principal Components. PC factors 1 and 2 (animals alert or looking, or hopping and moving out of area accounted for 36% of variance. PC factor 3 (eating cessation, taking flight, movement out of area accounted for 13% of variance. Factors 4 and 5 (relaxing, grooming and walking; 12 and 11% of variation, respectively discontinued upon playback. The whip crack was most evocative; eating was reduced from 75% of time spent prior to playback to 6% following playback (post alarm stomp: 32%, raven call: 49%, hiss: 75%. Additionally, 24% of individuals took flight and moved out of area (50 m radius in response to the whip crack (foot stomp: 0%, raven call: 8% and 4%, hiss: 6%. Increasing rate of presentation (12x/min ×2 min caused 71% of animals to move out of the area. CONCLUSIONS/SIGNIFICANCE: The bull whip crack, an artificial sound, was as effective as the alarm stomp at eliciting aversive behaviors. Kangaroos did not fully habituate despite hearing the signal up to 20x/min. Highest rates of playback did not elicit the greatest responses, suggesting that 'more is not always better'. Ultimately, by utilizing both artificial and biological sounds, predictability may be masked or offset, so that habituation is delayed and more effective deterrents may be produced.

  19. Fractal analysis of heart rate variability and mortality after an acute myocardial infarction

    DEFF Research Database (Denmark)

    Tapanainen, Jari M; Thomsen, Poul Erik Bloch; Køber, Lars

    2002-01-01

    The recently developed fractal analysis of heart rate (HR) variability has been suggested to provide prognostic information about patients with heart failure. This prospective multicenter study was designed to assess the prognostic significance of fractal and traditional HR variability parameters...... in a large, consecutive series of survivors of an acute myocardial infarction (AMI). A consecutive series of 697 patients were recruited to participate 2 to 7 days after an AMI in 3 Nordic university hospitals. The conventional time-domain and spectral parameters and the newer fractal scaling indexes of HR...... variability were analyzed from 24-hour RR interval recordings. During the mean follow-up of 18.4 +/- 6.5 months, 49 patients (7.0%) died. Of all the risk variables, a reduced short-term fractal scaling exponent (alpha(1)

  20. Association Between Major Depressive Disorder and Heart Rate Variability in the Netherlands Study of Depression and Anxiety (NESDA)

    NARCIS (Netherlands)

    Licht, Carmilla M. M.; de Geus, Eco J. C.; Zitman, Frans G.; Hoogendijk, Witte J. G.; van Dyck, Richard; Penninx, Brenda W. J. H.

    2008-01-01

    Context: It has been hypothesized that depression is associated with lower heart rate variability and decreased cardiac vagal control. This may play an important role in the risk of cardiovascular disease among depressed individuals. Objective: To determine whether heart rate variability was lower

  1. The Effect of Heart Rate on the Heart Rate Variability Response to Autonomic Interventions

    Directory of Open Access Journals (Sweden)

    George E Billman

    2013-08-01

    Full Text Available Heart rate variability (HRV, the beat-to-beat variation in either heart rate (HR or heart period (R-R interval, has become a popular clinical and investigational tool to quantify cardiac autonomic regulation. However, it is not widely appreciated that, due to the inverse curvilinear relationship between HR and R-R interval, HR per se can profoundly influence HRV. It is, therefore, critical to correct HRV for the prevailing HR particularly, as HR changes in response to autonomic neural activation or inhibition. The present study evaluated the effects of HR on the HRV response to autonomic interventions that either increased (submaximal exercise, n = 25 or baroreceptor reflex activation, n = 20 or reduced (pharmacological blockade: β-adrenergic receptor, muscarinic receptor antagonists alone and in combination, n = 25, or bilateral cervical vagotomy, n = 9 autonomic neural activity in a canine model. Both total (RR interval standard deviation, RRSD and the high frequency variability (HF, 0.2 to 1.04 Hz were determined before and in response to an autonomic intervention. All interventions that reduced or abolished cardiac parasympathetic regulation provoked large reductions in HRV even after HR correction [division by mean RRsec or (mean RRsec2 for RRSD and HF, respectively] while interventions that reduced HR yielded mixed results. β-adrenergic receptor blockade reduced HRV (RRSD but not HF while both RRSD and HF increased in response to increases in arterial blood (baroreceptor reflex activation even after HR correction. These data suggest that the physiological basis for HRV is revealed after correction for prevailing HR and, further, that cardiac parasympathetic activity is responsible for a major portion of the HRV in the dog.

  2. Cycling cadence affects heart rate variability

    International Nuclear Information System (INIS)

    Lunt, Heather C; Corbett, Jo; Barwood, Martin J; Tipton, Michael J

    2011-01-01

    The purpose of this study was to examine the effect different cycling cadences have on heart rate variability (HRV) when exercising at constant power outputs. Sixteen males had ECG and respiratory measurements recorded at rest and during 8, 10 min periods of cycling at four different cadences (40, 60, 80 and 100 revs min −1 ) and two power outputs (0 W (unloaded) and 100 W (loaded)). The cycling periods were performed following a Latin square design. Spectral analyses of R–R intervals by fast Fourier transforms were used to quantify absolute frequency domain HRV indices (ms 2 ) during the final 5 min of each bout, which were then log transformed using the natural logarithm (Ln). HRV indices of high frequency (HF) power were reduced when cadence was increased (during unloaded cycling (0 W) log transformed HF power decreased from a mean [SD] of 6.3 [1.4] Ln ms 2 at 40 revs min −1 to 3.9 [1.3] Ln ms 2 at 100 revs min −1 ). During loaded cycling (at 100 W), the low to high frequency (LF:HF) ratio formed a 'J' shaped curve as cadence increased from 40 revs min −1 (1.4 [0.4]) to 100 revs min −1 (1.9 [0.7]), but dipped below the 40 revs min −1 values during the 60 revs min −1 1.1 (0.3) and 80 revs min −1 1.2 (0.6) cadence conditions. Cardiac frequency (f C ) and ventilatory variables were strongly correlated with frequency domain HRV indices (r = −0.80 to −0.95). It is concluded that HRV indices are influenced by both cycling cadence and power output; this is mediated by the f C and ventilatory changes that occur as cadence or exercise intensity is increased. Consequently, if HRV is assessed during exercise, both power output/exercise intensity and cadence should be standardized

  3. Evolving changes in fetal heart rate variability and brain injury after hypoxia-ischaemia in preterm fetal sheep.

    Science.gov (United States)

    Yamaguchi, Kyohei; Lear, Christopher A; Beacom, Michael J; Ikeda, Tomoaki; Gunn, Alistair J; Bennet, Laura

    2018-01-08

    Fetal heart rate variability is a critical index of fetal wellbeing. Suppression of heart rate variability may provide prognostic information on the risk of hypoxic-ischaemic brain injury after birth. In the present study, we report the evolution of fetal heart rate variability after both mild and severe hypoxia-ischaemia. Both mild and severe hypoxia-ischaemia were associated with an initial, brief suppression of multiple measures of heart rate variability. This was followed by normal or increased levels of heart rate variability during the latent phase of injury. Severe hypoxia-ischaemia was subsequently associated with the prolonged suppression of measures of heart rate variability during the secondary phase of injury, which is the period of time when brain injury is no longer treatable. These findings suggest that a biphasic pattern of heart rate variability may be an early marker of brain injury when treatment or intervention is probably most effective. Hypoxia-ischaemia (HI) is a major contributor to preterm brain injury, although there are currently no reliable biomarkers for identifying infants who are at risk. We tested the hypothesis that fetal heart rate (FHR) and FHR variability (FHRV) would identify evolving brain injury after HI. Fetal sheep at 0.7 of gestation were subjected to either 15 (n = 10) or 25 min (n = 17) of complete umbilical cord occlusion or sham occlusion (n = 12). FHR and four measures of FHRV [short-term variation, long-term variation, standard deviation of normal to normal R-R intervals (SDNN), root mean square of successive differences) were assessed until 72 h after HI. All measures of FHRV were suppressed for the first 3-4 h in the 15 min group and 1-2 h in the 25 min group. Measures of FHRV recovered to control levels by 4 h in the 15 min group, whereas the 25 min group showed tachycardia and an increase in short-term variation and SDNN from 4 to 6 h after occlusion. The measures of FHRV then progressively

  4. Studying radon exhalation rates variability from phosphogypsum piles in the SW of Spain

    Energy Technology Data Exchange (ETDEWEB)

    López-Coto, I., E-mail: israel.lopez@dfa.uhu.es [Dpto. Física Aplicada, Facultad CC. Experimentales, University of Huelva, Campus de El Carmen s/n, 21007 Huelva (Spain); Mas, J.L. [Dpto. Física Aplicada I. Escuela Politécnica Superior, University of Sevilla, C/Virgen de Africa 7, 41012 Sevilla (Spain); Vargas, A. [Universitat Politècnica de Catalunya, Instituto de Técnicas Energéticas, Campus Sud Edificio ETSEIB, Planta 0, Pabellón C, Av. Diagonal 647, 08028 Barcelona (Spain); Bolívar, J.P. [Dpto. Física Aplicada, Facultad CC. Experimentales, University of Huelva, Campus de El Carmen s/n, 21007 Huelva (Spain)

    2014-09-15

    Highlights: • Variability of radon exhalation rates from PG piles has been studied using numerical simulation supported by experimental data. • Most relevant parameters controlling the exhalation rate are radon potential and moisture saturation. • Piling up the waste increasing the height instead of the surface allows the reduction of the exhalation rate. • A proposed cover here is expected to allow exhalation rates reductions up to 95%. - Abstract: Nearly 1.0 × 10{sup 8} tonnes of phosphogypsum were accumulated during last 50 years on a 1200 ha disposal site near Huelva town (SW of Spain). Previous measurements of exhalation rates offered very variable values, in such a way that a worst case scenario could not be established. Here, new experimental data coupled to numerical simulations show that increasing the moisture contents or the temperature reduces the exhalation rate whilst increasing the radon potential or porosity has the contrary effect. Once the relative effects are compared, it can be drawn that the most relevant parameters controlling the exhalation rate are radon potential (product of emanation factor by {sup 226}Ra concentration) and moisture saturation of PG. From wastes management point of view, it can be concluded that piling up the waste increasing the height instead of the surface allows the reduction of the exhalation rate. Furthermore, a proposed cover here is expected to allow exhalation rates reductions up to 95%. We established that the worst case scenario corresponds to a situation of extremely dry winter. Under these conditions, the radon exhalation rate (0.508 Bq m{sup −2} s{sup −1}) would be below though close to the upper limit established by U.S.E.P.A. for inactive phopsphogypsum piles (0.722 Bq m{sup −2} s{sup −1})

  5. Variable Rate Characteristic Waveform Interpolation Speech Coder Based on Phonetic Classification

    Institute of Scientific and Technical Information of China (English)

    WANG Jing; KUANG Jing-ming; ZHAO Sheng-hui

    2007-01-01

    A variable-bit-rate characteristic waveform interpolation (VBR-CWI) speech codec with about 1.8kbit/s average bit rate which integrates phonetic classification into characteristic waveform (CW) decomposition is proposed.Each input frame is classified into one of 4 phonetic classes.Non-speech frames are represented with Bark-band noise model.The extracted CWs become rapidly evolving waveforms (REWs) or slowly evolving waveforms (SEWs) in the cases of unvoiced or stationary voiced frames respectively, while mixed voiced frames use the same CW decomposition as that in the conventional CWI.Experimental results show that the proposed codec can eliminate most buzzy and noisy artifacts existing in the fixed-bit-rate characteristic waveform interpolation (FBR-CWI) speech codec, the average bit rate can be much lower, and its reconstructed speech quality is much better than FS 1016 CELP at 4.8kbit/s and similar to G.723.1 ACELP at 5.3kbit/s.

  6. Heart rate variability and swimming.

    Science.gov (United States)

    Koenig, Julian; Jarczok, Marc N; Wasner, Mieke; Hillecke, Thomas K; Thayer, Julian F

    2014-10-01

    Professionals in the domain of swimming have a strong interest in implementing research methods in evaluating and improving training methods to maximize athletic performance and competitive outcome. Heart rate variability (HRV) has gained attention in research on sport and exercise to assess autonomic nervous system activity underlying physical activity and sports performance. Studies on swimming and HRV are rare. This review aims to summarize the current evidence on the application of HRV in swimming research and draws implications for future research. A systematic search of databases (PubMed via MEDLINE, PSYNDEX and Embase) according to the PRISMA statement was employed. Studies were screened for eligibility on inclusion criteria: (a) empirical investigation (HRV) in humans (non-clinical); (b) related to swimming; (c) peer-reviewed journal; and (d) English language. The search revealed 194 studies (duplicates removed), of which the abstract was screened for eligibility. Fourteen studies meeting the inclusion criteria were included in the review. Included studies broadly fell into three classes: (1) control group designs to investigate between-subject differences (i.e. swimmers vs. non-swimmers, swimmers vs. other athletes); (2) repeated measures designs on within-subject differences of interventional studies measuring HRV to address different modalities of training or recovery; and (3) other studies, on the agreement of HRV with other measures. The feasibility and possibilities of HRV within this particular field of application are well documented within the existing literature. Future studies, focusing on translational approaches that transfer current evidence in general practice (i.e. training of athletes) are needed.

  7. Assessment of post-laparotomy pain in laboratory mice by telemetric recording of heart rate and heart rate variability

    Science.gov (United States)

    Arras, Margarete; Rettich, Andreas; Cinelli, Paolo; Kasermann, Hans P; Burki, Kurt

    2007-01-01

    Background Pain of mild to moderate grade is difficult to detect in laboratory mice because mice are prey animals that attempt to elude predators or man by hiding signs of weakness, injury or pain. In this study, we investigated the use of telemetry to identify indicators of mild-to-moderate post-laparotomy pain. Results Adult mice were subjected to laparotomy, either combined with pain treatment (carprofen or flunixin, 5 mg/kg s/c bid, for 1 day) or without pain relief. Controls received anesthesia and analgesics or vehicle only. Telemetrically measured locomotor activity was undisturbed in all animals, thus confirming that any pain experienced was of the intended mild level. No symptoms of pain were registered in any of the groups by scoring the animals' outer appearance or spontaneous and provoked behavior. In contrast, the group receiving no analgesic treatment after laparotomy demonstrated significant changes in telemetry electrocardiogram recordings: increased heart rate and decreased heart rate variability parameters pointed to sympathetic activation and pain lasting for 24 hours. In addition, core body temperature was elevated. Body weight and food intake were reduced for 3 and 2 days, respectively. Moreover, unstructured cage territory and destroyed nests appeared for 1–2 days in an increased number of animals in this group only. In controls these parameters were not affected. Conclusion In conclusion, real-time telemetric recordings of heart rate and heart rate variability were indicative of mild-to-moderate post-laparotomy pain and could define its duration in our mouse model. This level of pain cannot easily be detected by direct observation. PMID:17683523

  8. Mercury Exposure and Heart Rate Variability: A Systematic Review

    Science.gov (United States)

    Gribble, Matthew O.; Cheng, Alan; Berger, Ronald D.; Rosman, Lori; Guallar, Eliseo

    2015-01-01

    Background Mercury affects the nervous system and has been implicated in altering heart rhythm and function. We sought to better define its role in modulating heart rate variability, a well-known marker of cardiac autonomic function. Design Systematic review. Methods We searched PubMed, Embase, TOXLINE and DART databases without language restriction. We report findings as a qualitative systematic review because heterogeneity in study design and assessment of exposures and outcomes across studies, as well as other methodological limitations of the literature, precluded a quantitative meta-analysis. Results We identified 12 studies of mercury exposure and heart rate variability in human populations (10 studies involving primarily environmental methylmercury exposure and two studies involving occupational exposure to inorganic mercury) conducted in Japan, the Faroe Islands, Canada, Korea, French Polynesia, Finland and Egypt. The association of prenatal mercury exposure with lower high-frequency band scores (thought to reflect parasympathetic activity) in several studies, in particular the inverse association of cord blood mercury levels with the coefficient of variation of the R-R intervals and with low frequency and high frequency bands at 14 years of age in the Faroe Islands birth cohort study, suggests that early mercury exposure could have a long-lasting effect on cardiac parasympathetic activity. Studies with later environmental exposures to mercury in children or in adults were heterogeneous and did not show consistent associations. Conclusions The evidence was too limited to draw firm causal inferences. Additional research is needed to elucidate the effects of mercury on cardiac autonomic function, particularly as early-life exposures might have lasting impacts on cardiac parasympathetic function. PMID:26231507

  9. Changes in heart rate variability are associated with expression of short-term and long-term contextual and cued fear memories.

    Directory of Open Access Journals (Sweden)

    Jun Liu

    Full Text Available Heart physiology is a highly useful indicator for measuring not only physical states, but also emotional changes in animals. Yet changes of heart rate variability during fear conditioning have not been systematically studied in mice. Here, we investigated changes in heart rate and heart rate variability in both short-term and long-term contextual and cued fear conditioning. We found that while fear conditioning could increase heart rate, the most significant change was the reduction in heart rate variability which could be further divided into two distinct stages: a highly rhythmic phase (stage-I and a more variable phase (stage-II. We showed that the time duration of the stage-I rhythmic phase were sensitive enough to reflect the transition from short-term to long-term fear memories. Moreover, it could also detect fear extinction effect during the repeated tone recall. These results suggest that heart rate variability is a valuable physiological indicator for sensitively measuring the consolidation and expression of fear memories in mice.

  10. Rates of ingestion and their variability between individual calanoid copepods: Direct observations

    Energy Technology Data Exchange (ETDEWEB)

    Paffenhoefer, G.A.; Lewis, K.D. [Skidaway Inst. of Oceanography, Savannah, GA (United States); Bundy, M.H. [Skidaway Inst. of Oceanography, Savannah, GA (United States)]|[Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany). Inst. fuer Fernerkundung (IFE); Metz, C. [Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany). Inst. fuer Fernerkundung (IFE)

    1995-12-01

    The goals of this study were to determine rates of ingestion and fecal pellet release, and their variability, for individual planktonic copepods over extended periods of time (>20 min). Ingestions and rejections of individual cells of the diatom Thalassiosira eccentrica by a adult females of the calanoid Paracalanus aculeatus were directly quantified by observing individual copepods continuously at cell concentrations ranging from 0.1 to 1.2 mm{sup 3} l{sup {minus}1}. Average ingestion rates increased with increasing food concentration, but were not significantly different between 0.3 and 1.0 mm{sup 3} l{sup {minus}1} (9.8 and 32.7 {mu}g Cl{sup {minus}1}) of T.eccentrica. Rates of cell rejections were low and similar at 0.1 and 0.3. but were significantly higher at 1.0 mm{sup 3} l{sup {minus}1}. The coefficients of variation for average ingestion rates of individual copepods hardly differed between food concentrations, ranging from 17 to 22%, and were close to those for average fecal pellet release intervals which ranged from 15 to 21%. A comparison between individuals at each food concentration found no significant differences at 1.0; at 0.1 and 0.3 mm{sup 3} l{sup {minus}1}, respectively, ingestion rates of four out of five females did not differ significantly from each other. Average intervals between fecal pellet releases were similar at 0.3 and 1.0 mm{sup 3} l{sup {minus}1}. Fecal pellet release intervals between individuals were significantly different at each food concentration; these significant differences were attributed to rather narrow ranges of pellet release intervals of each individual female. Potential sources/causes of variability in the sizes and rates of copepods in the ocean are evaluated.

  11. VALUE OF HEART RATE VARIABILITY ANALYSIS IN DIAGNOSTICS OF THE EMOTIONAL STATE

    Directory of Open Access Journals (Sweden)

    І. Chaykovskyi

    2012-11-01

    Full Text Available The is presented the development of method for evaluation of emotional state of man, what suitable for use at the workplace based on analysis of heart rate (HR variability. 28 healthy volunteers were examined. 3 audiovisual clips were consistently presented on the display of the personal computer for each of them. One clip contained information originating the positive emotions, the second one – negative emotions, the third one – neutral. All possible pairs of the emotional states were analysed with help of one- and multi-dimensional linear discriminant analysis based on HR variability. Showing the emotional video-clips (of both signs causes reliable slowing of HR frequency and also some decreasing of HR variability. In addition, negative emotions cause regularizing and simplification of structural organization of heart rhythm. Accuracy of discrimination for pair “emotional – neutral” video clips was 98 %, for pair “rest – neutral” was 74 %, for pair “positive – negative” was 91 %. Analysis of HR variability enables to determine the emotional state of observed person at the workplace with high reliability.

  12. Physiological and performance adaptations to an in-season soccer camp in the heat: Associations with heart rate and heart rate variability

    DEFF Research Database (Denmark)

    Buchheit, M; Voss, S C; Nybo, Lars

    2011-01-01

    The aim of the present study was to examine the associations between adaptive responses to an in-season soccer training camp in the heat and changes in submaximal exercising heart rate (HRex, 5-min run at 9 ¿km/h), postexercise HR recovery (HRR) and HR variability (HRV). Fifteen well-trained but ......The aim of the present study was to examine the associations between adaptive responses to an in-season soccer training camp in the heat and changes in submaximal exercising heart rate (HRex, 5-min run at 9 ¿km/h), postexercise HR recovery (HRR) and HR variability (HRV). Fifteen well......-trained but non-heat-acclimatized male adult players performed a training week in Qatar (34.6¿±¿1.9°C wet bulb globe temperature). HRex, HRR, HRV (i.e. the standard deviation of instantaneous beat-to-beat R-R interval variability measured from Poincaré plots SD1, a vagal-related index), creatine kinase (CK...... at the beginning and at the end of the training week. Throughout the intervention, HRex and HRV showed decreasing (P¿...

  13. Wavelet and receiver operating characteristic analysis of heart rate variability

    Science.gov (United States)

    McCaffery, G.; Griffith, T. M.; Naka, K.; Frennaux, M. P.; Matthai, C. C.

    2002-02-01

    Multiresolution wavelet analysis has been used to study the heart rate variability in two classes of patients with different pathological conditions. The scale dependent measure of Thurner et al. was found to be statistically significant in discriminating patients suffering from hypercardiomyopathy from a control set of normal subjects. We have performed Receiver Operating Characteristc (ROC) analysis and found the ROC area to be a useful measure by which to label the significance of the discrimination, as well as to describe the severity of heart dysfunction.

  14. Heart rate variability, sleep, and the early detection of post-traumatic stress disorder

    NARCIS (Netherlands)

    van Boxtel, Geert J.M.; Cluitmans, Pierre J.M.; Raymann, Roy J.E.M.; Ouwerkerk, Martin; Denissen, Ad J.M.; Dekker, Marian K.J.; Sitskoorn, Margriet M.; Vermetten, E.; Germain, A.; Neylan, T.C.

    2017-01-01

    Measures of heart rate variability (HRV) are sensitive indices of autonomic nervous system functioning, capable of distinguishing activity of its two constituent branches, the sympathetic and parasympathetic nervous systems. As such, these measures are possibly useful as early markers of

  15. Influence of travel speed on spray deposition uniformity from an air-assisted variable-rate sprayer

    Science.gov (United States)

    A newly developed LiDAR-guided air-assisted variable-rate sprayer for nursery and orchard applications was tested at various travel speeds to compare its spray deposition and coverage uniformity with constant-rate applications. Spray samplers, including nylon screens and water-sensitive papers (WSP)...

  16. Changing maternity leave policy: short-term effects on fertility rates and demographic variables in Germany.

    Science.gov (United States)

    Thyrian, Jochen René; Fendrich, Konstanze; Lange, Anja; Haas, Johannes-Peter; Zygmunt, Marek; Hoffmann, Wolfgang

    2010-08-01

    Changes in reproductive behaviour and decreasing fertility rates have recently led to policy actions that attempt to counteract these developments. Evidence on the efficacy of such policy interventions, however, is limited. The present analysis examines fertility rates and demographic variables of a population in Germany in response to new maternity leave regulations, which were introduced in January 2007. As part of a population-based survey of neonates in Pomerania (SNiP), all births in the study region from the period 23 months prior to January 1st, 2007 until 23 months afterwards were examined. Crude Birth Rates (CBR) per month, General Fertility Rates (GFR) per month, parity and sociodemographic variables were compared using bivariate techniques. Logistic regression analysis was performed. No statistically significant difference in the CBR or GFR after Jan. 1st, 2007 was found. There were statistically significant differences in other demographic variables, however. The proportion of mothers who (a) were employed full-time before pregnancy; (b) came from a higher socioeconomic status; and (c) had higher income levels all increased after January 1st, 2007. The magnitude of these effects was higher in multigravid women. Forward stepwise logistic regression found an odds ratio of 1.79 for women with a family income of more than 3000 euro to give birth after the new law was introduced. This is the first analysis of population-based data that examines fertility rates and sociodemographic variables in response to new legal regulations. No short-term effects on birth rates were detected, but there was a differential effect on the subgroup of multigravidae. The focus of this policy was to provide financial support, which is certainly important, but the complexity of having a child suggests that attitudinal and motivational aspects also need to be taken into account. Furthermore, these analyses were only able to evaluate the short-term consequences of the policy

  17. THE IMPACT ON WOMEN ON THE REMOVAL OF GENDER AS A RATING VARIABLE IN MOTOR-VEHICLE INSURANCE

    Directory of Open Access Journals (Sweden)

    Anthea Natalie Wagener

    2013-04-01

    Full Text Available Insurers use actuarial statistics as rating variables to differentiate and distinguish for the purposes of risk classification. They justify their use of actuarial statistics due to its accuracy as a predictor of risk. South African motor-vehicle insurers use gender, inter alia, as a rating variable to classify risks into certain classes and to determine insurance premiums. Depending upon whether the insured is male or female, it could have a significant impact on the cost of his or her premium. Women drivers pay less for motor-vehicle insurance because actuarial statistics indicate that women are more careful drivers and are involved in 20 per cent fewer accidents than men. Men pay higher premiums because the statistics indicate that they are less responsible drivers than women.Should a South African court decide that the use of gender as a motor-vehicle insurance rating variable is unfair discrimination, this would benefit male drivers, as it would lower their premium. Women, on the other hand, would be disadvantaged as they would be required to pay higher premiums to subsidise men. The article examines the impact that the removal of gender as a rating variable in motor-vehicle insurance would have on women, and asks if the effects thereof would influence a South African Court’s decision in determining if the use of gender as a rating variable amounts to unfair discrimination. The article first considers the findings of American and Canadian Courts in determining this same issue and then considers South African equality legislation, particularly the Promotion of Equality and Prevention of Unfair Discrimination Act 4 of 2000 (“the Equality Act”. Thereafter, the article provides recommendations for a South African Court. As the Equality Act indicates that the discriminatory insurance practice of placing a disadvantage or advantage on persons based inter alia on their gender may possibly be unfair, it is suggested that South African

  18. Fractal scaling behavior of heart rate variability in response to meditation techniques

    International Nuclear Information System (INIS)

    Alvarez-Ramirez, J.; Rodríguez, E.; Echeverría, J.C.

    2017-01-01

    Highlights: • The scaling properties of heart rate variability in premeditation and meditation states were studied. • Mindfulness meditation induces a decrement of the HRV long-range scaling correlations. • Mindfulness meditation can be regarded as a type of induced deep sleep-like dynamics. - Abstract: The rescaled range (R/S) analysis was used for analyzing the fractal scaling properties of heart rate variability (HRV) of subjects undergoing premeditation and meditation states. Eight novice subjects and four advanced practitioners were considered. The corresponding pre-meditation and meditation HRV data were obtained from the Physionet database. The results showed that mindfulness meditation induces a decrement of the HRV long-range scaling correlations as quantified with the time-variant Hurst exponent. The Hurst exponent for advanced meditation practitioners decreases up to values of 0.5, reflecting uncorrelated (e.g., white noise-like) HRV dynamics. Some parallelisms between mindfulness meditation and deep sleep (Stage 4) are discussed, suggesting that the former can be regarded as a type of induced deep sleep-like dynamics.

  19. Heart rate variability parameters do not correlate with pain intensity in healthy volunteers

    NARCIS (Netherlands)

    Meeuse, Jan J; Löwik, Marco S P; Löwik, Sabine A M; Aarden, Eline; van Roon, Arie M; Gans, Reinold O B; van Wijhe, Marten; Lefrandt, Joop D; Reyners, Anna K L

    OBJECTIVE: When patients cannot indicate pain, physiological parameters may be useful. We tested whether heart rate variability (HRV) parameters, as reflection of sympathetic and vagal tone, can be used to quantify pain intensity. DESIGN: Prospective study. SUBJECTS AND SETTING: A standardized heat

  20. Theoretical growth rates, periods, and pulsation constants for long-period variables

    International Nuclear Information System (INIS)

    Fox, M.W.; Wood, P.R.

    1982-01-01

    Theoretical values of the growth rate, period, and pulsation constant for the first three radial pulsation modes in red giants (Population II and galactic disk) and supergiants have been derived in the linear, nonadiabatic approximation. The effects of altering the surface boundary conditions, the effective temperature (or mixing length), and the opacity in the outer layers have been explored. In the standard models, the Q-value for the first overtone can be much larger (Q 1 1 roughly-equal0.04); in addition, the Q-value for the fundamental mode is reduced from previous values, as is the period ratio P 0 /P 1 . The growth rate for the fundamental mode is found to increase with luminosity on the giant branch while the growth rate for the first overtone decreases. Dynamical instabilities found in previous adiabatic models of extreme red giants do not occur when nonadiabatic effects are included in the models. In some massive, luminous models, period ratios P 0 /P 1 approx.7 occur when P 0 approx.2000--5000 days; it is suggested that the massive galactic supergiants and carbon stars which have secondary periods Papprox.2000--7000 days and primary periods Papprox.300--700 days are first-overtone pulsators in which the long secondary periods are due to excitation of the fundamental mode. Some other consequences of the present results are briefly discussed, with particular emphasis on the mode of pulsation of the Mira variables. Subject headings: stars: long-period variables: stars: pulsation: stars: supergiants

  1. Variable Frame Rate and Length Analysis for Data Compression in Distributed Speech Recognition

    DEFF Research Database (Denmark)

    Kraljevski, Ivan; Tan, Zheng-Hua

    2014-01-01

    This paper addresses the issue of data compression in distributed speech recognition on the basis of a variable frame rate and length analysis method. The method first conducts frame selection by using a posteriori signal-to-noise ratio weighted energy distance to find the right time resolution...... length for steady regions. The method is applied to scalable source coding in distributed speech recognition where the target bitrate is met by adjusting the frame rate. Speech recognition results show that the proposed approach outperforms other compression methods in terms of recognition accuracy...... for noisy speech while achieving higher compression rates....

  2. Heart Rate Variability Correlates to Functional Aerobic Impairment in Hemodialysis Patients

    Directory of Open Access Journals (Sweden)

    Maria Angela Magalhães de Queiroz Carreira

    2015-06-01

    Full Text Available Background: Autonomic dysfunction (AD is highly prevalent in hemodialysis (HD patients and has been implicated in their increased risk of cardiovascular mortality. Objective: To correlate heart rate variability (HRV during exercise treadmill test (ETT with the values obtained when measuring functional aerobic impairment (FAI in HD patients and controls. Methods: Cross-sectional study involving HD patients and a control group. Clinical examination, blood sampling, transthoracic echocardiogram, 24-hour Holter, and ETT were performed. A symptom-limited ramp treadmill protocol with active recovery was employed. Heart rate variability was evaluated in time domain at exercise and recovery periods. Results: Forty-one HD patients and 41 controls concluded the study. HD patients had higher FAI and lower HRV than controls (p<0.001 for both. A correlation was found between exercise HRV (SDNN and FAI in both groups. This association was independent of age, sex, smoking, body mass index, diabetes, and clonidine or beta-blocker use, but not of hemoglobin levels. Conclusion: No association was found between FAI and HRV on 24-hour Holter or at the recovery period of ETT. Of note, exercise HRV was inversely correlated with FAI in HD patients and controls. (Arq Bras Cardiol. 2015; [online]. ahead print, PP.0-0

  3. Heart Rate Variability: New Perspectives on Physiological Mechanisms, Assessment of Self-regulatory Capacity, and Health risk.

    Science.gov (United States)

    McCraty, Rollin; Shaffer, Fred

    2015-01-01

    Heart rate variability, the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operates on different time scales to adapt to environmental and psychological challenges. This article briefly reviews neural regulation of the heart and offers some new perspectives on mechanisms underlying the very low frequency rhythm of heart rate variability. Interpretation of heart rate variability rhythms in the context of health risk and physiological and psychological self-regulatory capacity assessment is discussed. The cardiovascular regulatory centers in the spinal cord and medulla integrate inputs from higher brain centers with afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. We also discuss the intrinsic cardiac nervous system and the heart-brain connection pathways, through which afferent information can influence activity in the subcortical, frontocortical, and motor cortex areas. In addition, the use of real-time HRV feedback to increase self-regulatory capacity is reviewed. We conclude that the heart's rhythms are characterized by both complexity and stability over longer time scales that reflect both physiological and psychological functional status of these internal self-regulatory systems.

  4. Assessment of post-laparotomy pain in laboratory mice by telemetric recording of heart rate and heart rate variability

    Directory of Open Access Journals (Sweden)

    Kasermann Hans P

    2007-08-01

    Full Text Available Abstract Background Pain of mild to moderate grade is difficult to detect in laboratory mice because mice are prey animals that attempt to elude predators or man by hiding signs of weakness, injury or pain. In this study, we investigated the use of telemetry to identify indicators of mild-to-moderate post-laparotomy pain. Results Adult mice were subjected to laparotomy, either combined with pain treatment (carprofen or flunixin, 5 mg/kg s/c bid, for 1 day or without pain relief. Controls received anesthesia and analgesics or vehicle only. Telemetrically measured locomotor activity was undisturbed in all animals, thus confirming that any pain experienced was of the intended mild level. No symptoms of pain were registered in any of the groups by scoring the animals' outer appearance or spontaneous and provoked behavior. In contrast, the group receiving no analgesic treatment after laparotomy demonstrated significant changes in telemetry electrocardiogram recordings: increased heart rate and decreased heart rate variability parameters pointed to sympathetic activation and pain lasting for 24 hours. In addition, core body temperature was elevated. Body weight and food intake were reduced for 3 and 2 days, respectively. Moreover, unstructured cage territory and destroyed nests appeared for 1–2 days in an increased number of animals in this group only. In controls these parameters were not affected. Conclusion In conclusion, real-time telemetric recordings of heart rate and heart rate variability were indicative of mild-to-moderate post-laparotomy pain and could define its duration in our mouse model. This level of pain cannot easily be detected by direct observation.

  5. Robotic crabs reveal that female fiddler crabs are sensitive to changes in male display rate.

    Science.gov (United States)

    Mowles, Sophie L; Jennions, Michael D; Backwell, Patricia R Y

    2018-01-01

    Males often produce dynamic, repetitive courtship displays that can be demanding to perform and might advertise male quality to females. A key feature of demanding displays is that they can change in intensity: escalating as a male increases his signalling effort, but de-escalating as a signaller becomes fatigued. Here, we investigated whether female fiddler crabs, Uca mjoebergi , are sensitive to changes in male courtship wave rate. We performed playback experiments using robotic male crabs that had the same mean wave rate, but either escalated, de-escalated or remained constant. Females demonstrated a strong preference for escalating robots, but showed mixed responses to robots that de-escalated ('fast' to 'slow') compared to those that waved at a constant 'medium' rate. These findings demonstrate that females can discern changes in male display rate, and prefer males that escalate, but that females are also sensitive to past display rates indicative of prior vigour. © 2018 The Authors.

  6. Highly variable rates of genome rearrangements between hemiascomycetous yeast lineages.

    Directory of Open Access Journals (Sweden)

    2006-03-01

    Full Text Available Hemiascomycete yeasts cover an evolutionary span comparable to that of the entire phylum of chordates. Since this group currently contains the largest number of complete genome sequences it presents unique opportunities to understand the evolution of genome organization in eukaryotes. We inferred rates of genome instability on all branches of a phylogenetic tree for 11 species and calculated species-specific rates of genome rearrangements. We characterized all inversion events that occurred within synteny blocks between six representatives of the different lineages. We show that the rates of macro- and microrearrangements of gene order are correlated within individual lineages but are highly variable across different lineages. The most unstable genomes correspond to the pathogenic yeasts Candida albicans and Candida glabrata. Chromosomal maps have been intensively shuffled by numerous interchromosomal rearrangements, even between species that have retained a very high physical fraction of their genomes within small synteny blocks. Despite this intensive reshuffling of gene positions, essential genes, which cluster in low recombination regions in the genome of Saccharomyces cerevisiae, tend to remain syntenic during evolution. This work reveals that the high plasticity of eukaryotic genomes results from rearrangement rates that vary between lineages but also at different evolutionary times of a given lineage.

  7. Bilateral hegu acupoints have the same effect on the heart rate variability of the healthy subjects.

    Science.gov (United States)

    Guangjun, Wang; Yuying, Tian; Shuyong, Jia; Wenting, Zhou; Weibo, Zhang

    2014-01-01

    Background. The specificity of acupuncture points (acupoints) is one of the key concepts in traditional acupuncture theory, but the question of whether there is adequate scientific evidence to prove or disprove specificity has been vigorously debated in recent years. Acupoint laterality is an important aspect of acupoint specificity. Data is particularly scarce regarding the laterality of the same channel, namesake acupoint located on opposite sides of the body. Our previous study results suggest that Neiguan acupoint (PC6) has the laterality. The aim of this study was to investigate whether Hegu (LI4) also has laterality from the perspective of heart rate variability. Methods. A total of twenty-eight healthy female volunteers were recruited for this study and were randomly separated into the group I (n = 14) and the group II (n = 14) according to the register order. In the group I, left LI4 was stimulated in the first epoch and the right LI4 was stimulated in the second epoch. In the group II, right LI4 was stimulated in the first epoch and left LI4 was stimulated in the second epoch. Electrocardiogram was recorded and heart rate variability was analyzed. Results. The results show that there were no significant differences of heart rate variablity between the group I and the group II in the time domain and in the frequency domain. Conclusions. Bilateral Hegu acupoints have the same effect on the heart rate variability of the healthy subjects.

  8. Bilateral Hegu Acupoints Have the Same Effect on the Heart Rate Variability of the Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Wang Guangjun

    2014-01-01

    Full Text Available Background. The specificity of acupuncture points (acupoints is one of the key concepts in traditional acupuncture theory, but the question of whether there is adequate scientific evidence to prove or disprove specificity has been vigorously debated in recent years. Acupoint laterality is an important aspect of acupoint specificity. Data is particularly scarce regarding the laterality of the same channel, namesake acupoint located on opposite sides of the body. Our previous study results suggest that Neiguan acupoint (PC6 has the laterality. The aim of this study was to investigate whether Hegu (LI4 also has laterality from the perspective of heart rate variability. Methods. A total of twenty-eight healthy female volunteers were recruited for this study and were randomly separated into the group I (n=14 and the group II (n=14 according to the register order. In the group I, left LI4 was stimulated in the first epoch and the right LI4 was stimulated in the second epoch. In the group II, right LI4 was stimulated in the first epoch and left LI4 was stimulated in the second epoch. Electrocardiogram was recorded and heart rate variability was analyzed. Results. The results show that there were no significant differences of heart rate variablity between the group I and the group II in the time domain and in the frequency domain. Conclusions. Bilateral Hegu acupoints have the same effect on the heart rate variability of the healthy subjects.

  9. Resting heart rate variability is associated with ex-Gaussian metrics of intra-individual reaction time variability.

    Science.gov (United States)

    Spangler, Derek P; Williams, DeWayne P; Speller, Lassiter F; Brooks, Justin R; Thayer, Julian F

    2018-03-01

    The relationships between vagally mediated heart rate variability (vmHRV) and the cognitive mechanisms underlying performance can be elucidated with ex-Gaussian modeling-an approach that quantifies two different forms of intra-individual variability (IIV) in reaction time (RT). To this end, the current study examined relations of resting vmHRV to whole-distribution and ex-Gaussian IIV. Subjects (N = 83) completed a 5-minute baseline while vmHRV (root mean square of successive differences; RMSSD) was measured. Ex-Gaussian (sigma, tau) and whole-distribution (standard deviation) estimates of IIV were derived from reaction times on a Stroop task. Resting vmHRV was found to be inversely related to tau (exponential IIV) but not to sigma (Gaussian IIV) or the whole-distribution standard deviation of RTs. Findings suggest that individuals with high vmHRV can better prevent attentional lapses but not difficulties with motor control. These findings inform the differential relationships of cardiac vagal control to the cognitive processes underlying human performance. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  10. Modest weight loss in moderately overweight postmenopausal women improves heart rate variability

    DEFF Research Database (Denmark)

    Mouridsen, Mette Rauhe; Bendsen, Nathalie Tommerup; Astrup, Arne

    2013-01-01

    Purpose: To evaluate the effects of weight loss on heart rate (HR) and heart rate variability (HRV) parameters in overweight postmenopausal women. Design and Methods: Forty-nine overweight postmenopausal women with an average body mass index of 28.8 1.9 kg/m2 underwent a 12-week dietary weight......-to-normal intervals for each 5-min period (SDNNindex). Baseline body fat mass (FM%) and changes in body composition was determined by dual X-ray absorptiometry. Before and after the weight-loss period, total abdominal fat, intra-abdominal fat (IAAT), and subcutaneous abdominal fat (SCAT) were measured by single...

  11. ARTiiFACT: a tool for heart rate artifact processing and heart rate variability analysis.

    Science.gov (United States)

    Kaufmann, Tobias; Sütterlin, Stefan; Schulz, Stefan M; Vögele, Claus

    2011-12-01

    The importance of appropriate handling of artifacts in interbeat interval (IBI) data must not be underestimated. Even a single artifact may cause unreliable heart rate variability (HRV) results. Thus, a robust artifact detection algorithm and the option for manual intervention by the researcher form key components for confident HRV analysis. Here, we present ARTiiFACT, a software tool for processing electrocardiogram and IBI data. Both automated and manual artifact detection and correction are available in a graphical user interface. In addition, ARTiiFACT includes time- and frequency-based HRV analyses and descriptive statistics, thus offering the basic tools for HRV analysis. Notably, all program steps can be executed separately and allow for data export, thus offering high flexibility and interoperability with a whole range of applications.

  12. Drowsiness detection using heart rate variability.

    Science.gov (United States)

    Vicente, José; Laguna, Pablo; Bartra, Ariadna; Bailón, Raquel

    2016-06-01

    It is estimated that 10-30 % of road fatalities are related to drowsy driving. Driver's drowsiness detection based on biological and vehicle signals is being studied in preventive car safety. Autonomous nervous system activity, which can be measured noninvasively from the heart rate variability (HRV) signal obtained from surface electrocardiogram, presents alterations during stress, extreme fatigue and drowsiness episodes. We hypothesized that these alterations manifest on HRV and thus could be used to detect driver's drowsiness. We analyzed three driving databases in which drivers presented different sleep-deprivation levels, and in which each driving minute was annotated as drowsy or awake. We developed two different drowsiness detectors based on HRV. While the drowsiness episodes detector assessed each minute of driving as "awake" or "drowsy" with seven HRV derived features (positive predictive value 0.96, sensitivity 0.59, specificity 0.98 on 3475 min of driving), the sleep-deprivation detector discerned if a driver was suitable for driving or not, at driving onset, as function of his sleep-deprivation state. Sleep-deprivation state was estimated from the first three minutes of driving using only one HRV feature (positive predictive value 0.80, sensitivity 0.62, specificity 0.88 on 30 drivers). Incorporating drowsiness assessment based on HRV signal may add significant improvements to existing car safety systems.

  13. Autonomic dysfunction in HIV patients on antiretroviral therapy: studies of heart rate variability

    DEFF Research Database (Denmark)

    Lebech, Anne-Mette; Kristoffersen, Ulrik Sloth; Mehlsen, Jesper

    2007-01-01

    of healthy volunteers (n = 12) were included. All were non-smokers, non-diabetic and had never received medication for dyslipidaemia or hypertension. Following a 10 min resting period a 5 min ECG recording was performed. Heart rate variability (HRV) analysis was performed in accordance with current...

  14. Effects of Variable Production Rate and Time-Dependent Holding Cost for Complementary Products in Supply Chain Model

    Directory of Open Access Journals (Sweden)

    Mitali Sarkar

    2017-01-01

    Full Text Available Recently, a major trend is going to redesign a production system by controlling or making variable the production rate within some fixed interval to maintain the optimal level. This strategy is more effective when the holding cost is time-dependent as it is interrelated with holding duration of products and rate of production. An effort is made to make a supply chain model (SCM to show the joint effect of variable production rate and time-varying holding cost for specific type of complementary products, where those products are made by two different manufacturers and a common retailer makes them bundle and sells bundles to end customers. Demand of each product is specified by stochastic reservation prices with a known potential market size. Those players of the SCM are considered with unequal power. Stackelberg game approach is employed to obtain global optimum solution of the model. An illustrative numerical example, graphical representation, and managerial insights are given to illustrate the model. Results prove that variable production rate and time-dependent holding cost save more than existing literature.

  15. Spectral analyses of systolic blood pressure and heart rate variability and their association with cognitive performance in elderly hypertensive subjects.

    Science.gov (United States)

    Santos, W B; Matoso, J M D; Maltez, M; Gonçalves, T; Casanova, M; Moreira, I F H; Lourenço, R A; Monteiro, W D; Farinatti, P T V; Soares, P P; Oigman, W; Neves, M F T; Correia, M L G

    2015-08-01

    Systolic hypertension is associated with cognitive decline in the elderly. Altered blood pressure (BP) variability is a possible mechanism of reduced cognitive performance in elderly hypertensives. We hypothesized that altered beat-to-beat systolic BP variability is associated with reduced global cognitive performance in elderly hypertensive subjects. In exploratory analyses, we also studied the correlation between diverse discrete cognitive domains and indices of systolic BP and heart rate variability. Disproving our initial hypothesis, we have shown that hypertension and low education, but not indices of systolic BP and heart rate variability, were independent predictors of lower global cognitive performance. However, exploratory analyses showed that the systolic BP variability in semi-upright position was an independent predictor of matrix reasoning (B = 0.08 ± .03, P-value = 0.005), whereas heart rate variability in semi-upright position was an independent predictor of the executive function score (B = -6.36 ± 2.55, P-value = 0.02). We conclude that myogenic vascular and sympathetic modulation of systolic BP do not contribute to reduced global cognitive performance in treated hypertensive subjects. Nevertheless, our results suggest that both systolic BP and heart rate variability might be associated with modulation of frontal lobe cognitive domains, such as executive function and matrix reasoning.

  16. Guided imagery, anxiety, heart rate, and heart rate variability during centrifuge training.

    Science.gov (United States)

    Jing, Xiaolu; Wu, Ping; Liu, Fang; Wu, Bin; Miao, Danmin

    2011-02-01

    Centrifuge training is an important method of improving the hypergravity tolerance of pilots, cosmonauts, and Chinese astronauts. However, the concomitants of tension or anxiety often impede training. Guided imagery (GI), a mind-body relaxation technique, provides a behavioral and cognitive means whereby individuals are able to exert control over the focus of attention. This study aims to investigate the immediate effects of GI for reducing stress in centrifuge training. There were 12 healthy young men who were randomly assigned to a GI group or music group. We measured changes in heart rate during centrifuge training, in heart rate variability before and after centrifuge training, and also evaluated relaxation and anxiety in three phases: before intervention, after intervention, and following centrifuge training. The change in the pattern of anxiety was different in the two groups over the three phases. Anxiety (measured by State Anxiety Inventory) in the GI group changed from 31.7 +/- 5.9 to 26.8 +/- 2.6 and 27.8 +/- 4.1, whereas for the music group this changed from 32.2 +/- 7.6 to 31.2 +/- 8.3 and 26.8 +/- 6.8. During centrifuge training, the maximal HR for the GI group (101.2 +/- 8.8) was lower than that of the music group (123.0 +/- 19.1). In addition GI showed a decrease in low frequency (LF, 0.04-0.15 Hz) components and an increase in high frequency (HF, 0.15-0.4 Hz) components before and after centrifuge training. GI was capable of decreasing tension, anxiety, and sympathetic nervous system activity pre- or post-centrifugation.

  17. Sleep Quality Estimation based on Chaos Analysis for Heart Rate Variability

    Science.gov (United States)

    Fukuda, Toshio; Wakuda, Yuki; Hasegawa, Yasuhisa; Arai, Fumihito; Kawaguchi, Mitsuo; Noda, Akiko

    In this paper, we propose an algorithm to estimate sleep quality based on a heart rate variability using chaos analysis. Polysomnography(PSG) is a conventional and reliable system to diagnose sleep disorder and to evaluate its severity and therapeatic effect, by estimating sleep quality based on multiple channels. However, a recording process requires a lot of time and a controlled environment for measurement and then an analyzing process of PSG data is hard work because the huge sensed data should be manually evaluated. On the other hand, it is focused that some people make a mistake or cause an accident due to lost of regular sleep and of homeostasis these days. Therefore a simple home system for checking own sleep is required and then the estimation algorithm for the system should be developed. Therefore we propose an algorithm to estimate sleep quality based only on a heart rate variability which can be measured by a simple sensor such as a pressure sensor and an infrared sensor in an uncontrolled environment, by experimentally finding the relationship between chaos indices and sleep quality. The system including the estimation algorithm can inform patterns and quality of own daily sleep to a user, and then the user can previously arranges his life schedule, pays more attention based on sleep results and consult with a doctor.

  18. The effects of exposure to environmental factors on Heart Rate Variability: An ecological perspective

    International Nuclear Information System (INIS)

    Schnell, Izhak; Potchter, Oded; Epstein, Yoram; Yaakov, Yaron; Hermesh, Hagai; Brenner, Shmuel; Tirosh, Emanuel

    2013-01-01

    The impact of human exposure to environmental factors on Heart Rate Variability (HRV) was examined in the urban space of Tel-Aviv-Jaffa. Four environmental factors were investigated: thermal and social loads; CO concentrations and noise. Levels of HRV are explained mainly by subjective social stresses, noise and CO. The most interesting result is the fact that while subjective social stress and noise increase HRV, low levels of CO are reducing HRV to some extent moderating the impact of subjective social stress and noise. Beyond the poisoning effect of CO and the fact that extremely low levels of HRV associated with high dozes of CO increase risk for life, low levels of CO may have a narcotic effect, as it is measured by HRV. The effects of thermal loads on HRV are negligible probably due to the use of behavioral means in order to neutralize heat and cold effects. -- Highlights: ► The impact of human exposure to environmental factors on Heart Rate Variability (HRV) was examined. ► Previous studies measured human exposure to pollution by fixed monitoring stations. ► This study measured actual personal exposure by mini sensors. ► High level of subjective social load and noise increase HRV. ► Low levels of CO may have a narcotic effect, as it is measured by HRV. -- The research focuses on the effects of environmental factors; noise, subjective social stress, thermal load and CO on Heart Rate Variability

  19. Effects of slow breathing rate on heart rate variability and arterial baroreflex sensitivity in essential hypertension.

    Science.gov (United States)

    Li, Changjun; Chang, Qinghua; Zhang, Jia; Chai, Wenshu

    2018-05-01

    This study is to investigate the effects of slow breathing on heart rate variability (HRV) and arterial baroreflex sensitivity in essential hypertension.We studied 60 patients with essential hypertension and 60 healthy controls. All subjects underwent controlled breathing at 8 and 16 breaths per minute. Electrocardiogram, respiratory, and blood pressure signals were recorded simultaneously. We studied effects of slow breathing on heart rate, blood pressure and respiratory peak, high-frequency (HF) power, low-frequency (LF) power, and LF/HF ratio of HRV with traditional and corrected spectral analysis. Besides, we tested whether slow breathing was capable of modifying baroreflex sensitivity in hypertensive subjects.Slow breathing, compared with 16 breaths per minute, decreased the heart rate and blood pressure (all P hypertensive subjects. Slow breathing increased baroreflex sensitivity in hypertensive subjects (from 59.48 ± 6.39 to 78.93 ± 5.04 ms/mm Hg, P hypertension. Besides, slow breathing increased baroreflex sensitivity in hypertensive subjects. These demonstrate slow breathing is indeed capable of shifting sympatho-vagal balance toward vagal activities and increasing baroreflex sensitivity, suggesting a safe, therapeutic approach for essential hypertension.

  20. Metabolic Syndrome and Short-Term Heart Rate Variability in Adults with Intellectual Disabilities

    Science.gov (United States)

    Chang, Yaw-Wen; Lin, Jin-Ding; Chen, Wei-Liang; Yen, Chia-Feng; Loh, Ching-Hui; Fang, Wen-Hui; Wu, Li-Wei

    2012-01-01

    Metabolic syndrome (MetS) increases the risk of cardiovascular events. Heart rate variability (HRV) represents autonomic functioning, and reduced HRV significantly increases cardiovascular mortality. The aims of the present paper are to assess the prevalence of MetS in adults with intellectual disabilities (ID), the difference in short-term HRV…

  1. An Epidemic Model of Computer Worms with Time Delay and Variable Infection Rate

    Directory of Open Access Journals (Sweden)

    Yu Yao

    2018-01-01

    Full Text Available With rapid development of Internet, network security issues become increasingly serious. Temporary patches have been put on the infectious hosts, which may lose efficacy on occasions. This leads to a time delay when vaccinated hosts change to susceptible hosts. On the other hand, the worm infection is usually a nonlinear process. Considering the actual situation, a variable infection rate is introduced to describe the spread process of worms. According to above aspects, we propose a time-delayed worm propagation model with variable infection rate. Then the existence condition and the stability of the positive equilibrium are derived. Due to the existence of time delay, the worm propagation system may be unstable and out of control. Moreover, the threshold τ0 of Hopf bifurcation is obtained. The worm propagation system is stable if time delay is less than τ0. When time delay is over τ0, the system will be unstable. In addition, numerical experiments have been performed, which can match the conclusions we deduce. The numerical experiments also show that there exists a threshold in the parameter a, which implies that we should choose appropriate infection rate β(t to constrain worm prevalence. Finally, simulation experiments are carried out to prove the validity of our conclusions.

  2. Overnight weight loss: relationship with sleep structure and heart rate variability

    OpenAIRE

    Walter Moraes; Dalva Poyares; Christian Guilleminault; Agostinho Rosa; Marco Tulio Mello; Adriana Rueda; Sergio Tufik

    2008-01-01

    Background: Weight loss can be caused by a loss of body mass due to metabolism and by water loss as unsensible water loss, sweating, or excretion in feces and urine. Although weight loss during sleep is a well-known phenomenon, it has not yet been studied in relation to sleep structure or autonomic tonus during sleep. Our study is proposed to be a first step in assessing the relationship between overnight weight loss, sleep structure, and HRV (heart rate variability) parameters.Methods: Twent...

  3. Effects of work stress on work-related rumination, restful sleep, and nocturnal heart rate variability experienced on workdays and weekends.

    Science.gov (United States)

    Vahle-Hinz, Tim; Bamberg, Eva; Dettmers, Jan; Friedrich, Niklas; Keller, Monika

    2014-04-01

    The present study reports the lagged effects of work stress on work-related rumination, restful sleep, and nocturnal heart rate variability experienced during both workdays and weekends. Fifty employees participated in a diary study. Multilevel and regression analyses revealed a significant relationship between work stress measured at the end of a workday, work-related rumination measured during the evening, and restful sleep measured the following morning. Work stress, measured as the mean of 2 consecutive workdays, was substantially but not significantly related to restful sleep on weekends. Work stress was unrelated to nocturnal heart rate variability. Work-related rumination was related to restful sleep on weekends but not on workdays. Additionally, work-related rumination on weekends was positively related to nocturnal heart rate variability during the night between Saturday and Sunday. No mediation effects of work stress on restful sleep or nocturnal heart rate variability via work-related rumination were confirmed.

  4. The effect of relaxing music on heart rate and heart rate variability during ECG GATED-myocardial perfusion scintigraphy.

    Science.gov (United States)

    Tan, Yusuf Ziya; Ozdemir, Semra; Temiz, Ahmet; Celik, Fatmanur

    2015-05-01

    The positive changes in human behavior caused by relaxing music demonstrate the psychological effect of music on human body. A meta-analytical study has shown that relaxing music affects blood pressure and heart rate in coronary heart patients and cancer patients. The aim of our study is to research whether there is a significant effect on heart rate and heart rate variability due to listening to relaxing music during ECG GATED MPS imaging under gamma camera. The music group (n = 50 patients) could choose from 15 different musical types including folk music (no lyric). The other 50 patients were placed in a "no music group" and did not get headphones or any music. There was a statistically significant reduction in the heart rate of patients in the music group compared to those in the control group. Relaxing music provides great benefits to both patient and clinician. There is close relationship between relaxing music and health procedure, can use every area of the health noninvasiv, safe, cheap and is a method don't have side effect. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Inter- and intra-annual chemical variability during the ice-free season in lakes with different flushing rates and acid deposition histories.

    Science.gov (United States)

    Arnott, Shelley E; Dillon, Peter J; Somers, Keith; Keller, Bill

    2003-01-01

    Quantifying chemical variability in different lake types is important for the assessment of both chemical and biological responses to environmental change. For monitoring programs that emphasize a large number of lakes at the expense of frequent samples, high variability may influence how representative single samples are of the average conditions of individual lakes. Intensive temporal data from long-term research sites provide a unique opportunity to assess chemical variability in lakes with different characteristics. We compared the intra- and inter-annual variability of four acidification related variables (Gran alkalinity, pH, sulphate concentration, and total base cation concentration) in four lakes with different flushing rates and acid deposition histories. Variability was highest in lakes with high flushing rates and was not influenced by historic acid deposition in our study lakes. This has implications for the amount of effort required in monitoring programs. Lakes with high flushing rates will require more frequent sampling intervals than lakes with low flushing rates. Consideration of specific lake types should be included in the design of monitoring programs.

  6. Heart rate variability analysed by Poincaré plot in patients with metabolic syndrome

    Czech Academy of Sciences Publication Activity Database

    Kubíčková, A.; Kozumplík, J.; Nováková, Z.; Plachý, M.; Jurák, Pavel; Lipoldová, J.

    2016-01-01

    Roč. 49, č. 1 (2016), s. 23-28 ISSN 0022-0736 R&D Projects: GA ČR GAP102/12/2034 Institutional support: RVO:68081731 Keywords : heart rate variability * metabolic syndrome * Poincaré plot * tilt table test * controlled breathing Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.514, year: 2016

  7. Spray deposition inside tree canopies from a newly developed variable-rate air assisted sprayer

    Science.gov (United States)

    Conventional spray applications in orchards and ornamental nurseries are not target-oriented, resulting in significant waste of pesticides and contamination of the environment. To address this problem, a variable-rate air-assisted sprayer implementing laser scanning technology was developed to apply...

  8. Effect of specimen geometry on the variability in fatigue crack growth rate

    International Nuclear Information System (INIS)

    Tsuji, Hirokazu; Nakajima, Hajime; Kondo, Tatsuo

    1982-02-01

    Fatigue crack growth tests on SA 533 grade B class 1 steel were conducted in air with both contoured double cantilever beam (CDCB) specimens and compact-tension (CT) specimens for comparison, which corresponded to the ΔK constant and ΔK increasing fatigue tests respectively. The variability of the measured values was examined statistically, and possible sources of the determined variability were discussed. The variability in the ΔK increasing fatigue tests with the CT specimens was found to be substantially greater than that in the ΔK constant fatigue tests with the CDCB specimens employed in the present study. In addition, the width of the scatter as well as in the degree of deviation from the expected linearity in da/dN versus ΔK plots were found to be varied depending on the level of ΔK in the CT specimen. Based on the results, a conclusion was drawn that constant ΔK type tests should be preferred in the tests where accuracy and reproducibility of crack growth rate measurement was of particular importance. (author)

  9. Changes in heart rate and heart rate variability as a function of age in Thoroughbred horses.

    Science.gov (United States)

    Ohmura, Hajime; Jones, James H

    2017-01-01

    We investigated changes in heart rate (HR) and HR variability as a function of age in newborn foals to old Thoroughbred horses. Experiments were performed on a total of 83 healthy and clinically normal Thoroughbred horses. Resting HR decreased with age from birth. The relationship between age and HR fit the equation Y=48.2X -0.129 (R 2 =0.705); the relationship between age and HR for horses 0-7 years old fit the equation Y=44.1X -0.179 (R 2 =0.882). Seven-day-old horses had the highest HR values (106 ± 10.3 beat/min). The low frequency (LF) and high frequency (HF) powers increased with age in newborn to old horses. These changes in HR and HR variability appear to result from the effects of ageing. Three- to seven-year-old race horses had the lowest HR values (32.9 ± 3.5 beat/min) and the highest LF and HF powers except for the HF powers in the oldest horses. Race training may have contributed to these changes. Horses of ages greater than 25 years old had the highest HF powers and the lowest LF/HF ratios. In individual horses, 8 of the 15 horses over 25 years old had LF/HF ratios of less than 1.0; their HR variability appears to be unique, and they may have a different autonomic balance than horses of younger age.

  10. Heart rate variability analysis in postural orthostatic tachycardia syndrome: a case report

    Directory of Open Access Journals (Sweden)

    Raffaele Calabrò

    2006-09-01

    Full Text Available The authors present a case of 36 year old male patient with idiopathic postural orthostatic tachycardia syndrome (POTS diagnosed during head-up tilt testing. Power spectral analysis of heart rate variability (HRV during the tilt test revealed that the ratio of low and high frequency powers (LF/HF increased with the onset of orthostatic intolerance. This analysis confirmed in our patient a strong activation in sympathetic tone.

  11. Integration of aerial imaging and variable-rate technology for site-specific aerial herbicide application

    Science.gov (United States)

    As remote sensing and variable rate technology are becoming more available for aerial applicators, practical methodologies on effective integration of these technologies are needed for site-specific aerial applications of crop production and protection materials. The objectives of this study were to...

  12. Features of heart rate variability capture regulatory changes during kangaroo care in preterm infants

    NARCIS (Netherlands)

    Kommers, D.R.; Joshi, R.; van Pul, C.; Atallah, N.L.; Feijs, L.M.G.; Oei, S.G.; Bambang Oetomo, S.; Andriessen, P.

    2017-01-01

    Objective: To determine whether heart rate variability (HRV) can serve as a surrogate measure to track regulatory changes during kangaroo care, a period of parental coregulation distinct from regulation within the incubator. Study design: Nurses annotated the starting and ending times of kangaroo

  13. Correlations between the Poincaré plot and conventional heart rate variability parameters assessed during paced breathing

    NARCIS (Netherlands)

    Guzik, P.; Piskorski, J.; Krauze, T.; Schneider, R.; Wesseling, K.H.; Wykrȩtowicz, A.; Wysocki, H.

    2007-01-01

    Aim: To analyze the correlation of the Poincaré plot descriptors of RR intervals with standard measures of heart rate variability (HRV) and spontaneous baroreflex sensitivity (BRS). A physiological model of changing respiratory rates from 6 to 15 breaths/min provided a wide range of RR intervals for

  14. Heart Rate Variability in Nonlinear Rats with Different Orientation and Exploratory Activity in the Open Field.

    Science.gov (United States)

    Kur'yanova, E V; Teplyi, D L; Zhukova, Yu D; Zhukovina, N V

    2015-12-01

    The basic behavioral activity of nonlinear rats was evaluated from the sum of crossed peripheral and central squares and peripheral and central rearing postures in the open fi eld test. This index was low (30 episodes). Male rats with high score of orientation and exploratory activity were characterized by higher indexes of total heart rate variability than rats with low or intermediate activity. Specimens with a greater contribution of VLF waves into the total power spectrum of heart rate variability were shown to dominate among the rats with high behavioral activity. Our results are consistent with the notions of a suprasegmental nature of VLF waves.

  15. Can Wearable Devices Accurately Measure Heart Rate Variability? A Systematic Review.

    Science.gov (United States)

    Georgiou, Konstantinos; Larentzakis, Andreas V; Khamis, Nehal N; Alsuhaibani, Ghadah I; Alaska, Yasser A; Giallafos, Elias J

    2018-03-01

    A growing number of wearable devices claim to provide accurate, cheap and easily applicable heart rate variability (HRV) indices. This is mainly accomplished by using wearable photoplethysmography (PPG) and/or electrocardiography (ECG), through simple and non-invasive techniques, as a substitute of the gold standard RR interval estimation through electrocardiogram. Although the agreement between pulse rate variability (PRV) and HRV has been evaluated in the literature, the reported results are still inconclusive especially when using wearable devices. The purpose of this systematic review is to investigate if wearable devices provide a reliable and precise measurement of classic HRV parameters in rest as well as during exercise. A search strategy was implemented to retrieve relevant articles from MEDLINE and SCOPUS databases, as well as, through internet search. The 308 articles retrieved were reviewed for further evaluation according to the predetermined inclusion/exclusion criteria. Eighteen studies were included. Sixteen of them integrated ECG - HRV technology and two of them PPG - PRV technology. All of them examined wearable devices accuracy in RV detection during rest, while only eight of them during exercise. The correlation between classic ECG derived HRV and the wearable RV ranged from very good to excellent during rest, yet it declined progressively as exercise level increased. Wearable devices may provide a promising alternative solution for measuring RV. However, more robust studies in non-stationary conditions are needed using appropriate methodology in terms of number of subjects involved, acquisition and analysis techniques implied.

  16. Simultaneous measurement of instantaneous heart rate and chest wall plethysmography in short-term, metronome guided heart rate variability studies: suitability for assessment of autonomic dysfunction.

    Science.gov (United States)

    Perring, S; Jones, E

    2003-08-01

    Instantaneous heart rate and chest wall motion were measured using a 3-lead ECG and an air pressure chest wall plethysmography system. Chest wall plethysmography traces were found to accurately represent the breathing pattern as measured by spirometry (average correlation coefficient 0.944); though no attempt was made to calibrate plethysmography voltage output to tidal volume. Simultaneous measurements of heart rate and chest wall motion were made for short periods under metronome guided breathing at 6 breaths per minute. The average peak to trough heart rate change per breath cycle (AVEMAX) and maximum correlation between heart rate and breathing cycle (HRBRCORR) were measured. Studies of 44 normal volunteers indicated clear inverse correlation of heart rate variability parameters with age (AVEMAX R = -0.502, P < 0.001) but no significant change in HRBRCORR with age (R = -0.115). Comparison of normal volunteers with diabetics with no history of symptoms associated with autonomic failure indicated significant lower heart rate variability in diabetics (P = 0.005 for AVEMAX) and significantly worse correlation between heart rate and breathing (P < 0.001 for HRBRCORR). Simultaneous measurement of heart rate and breathing offers the possibility of more sensitive diagnosis of autonomic failure in a simple bedside test and gives further insight into the nature of cardio-ventilatory coupling.

  17. Heart rate variability changes in business process outsourcing employees working in shifts.

    Science.gov (United States)

    Kunikullaya, Kirthana U; Kirthi, Suresh K; Venkatesh, D; Goturu, Jaisri

    2010-10-31

    Irregular and poor quality sleep is common in business process outsourcing (BPO) employees due to continuous shift working. The influence of this on the cardiac autonomic activity was investigated by the spectral analysis of heart rate variability (HRV). 36 night shift BPO employees (working from 22:00 to 06:00h) and 36 age and sex matched day shift BPO employees (working from 08:00 to 16:00h) were recruited for the study. Five minute electrocardiogram (ECG) was recorded in all the subjects. Heart rate variability was analyzed by fast Fourier transformation using RMS Vagus HRV software. The results were analyzed using Mann Whitney U test, Student t-test, Wilcoxon signed rank test and were expressed as mean ± SD. Sleepiness was significantly higher among night shift workers as measured by Epworth Sleepiness Scale (p<0.001). Night shift BPO employees were found to have a trend towards lower values of vagal parameters - HF power (ms(2)), and higher values of sympathovagal parameters like LF Power (ms(2)) and the LF/HF power (%) suggesting decreased vagal activity and sympathetic over activity, when compared to day shift employees. However, HRV parameters did not vary significantly between the day shift employees and night shift workers baseline values, and also within the night shift group. Night shift working increased the heart rate and shifted the sympathovagal balance towards sympathetic dominance and decreased vagal parameters of HRV. This is an indicator of unfavorable change in the myocardial system, and thus shows increased risk of cardiovascular disease among the night shift employees.

  18. Difference infiltrometer: a method to measure temporally variable infiltration rates during rainstorms

    Science.gov (United States)

    Moody, John A.; Ebel, Brian A.

    2012-01-01

    We developed a difference infiltrometer to measure time series of non-steady infiltration rates during rainstorms at the point scale. The infiltrometer uses two, tipping bucket rain gages. One gage measures rainfall onto, and the other measures runoff from, a small circular plot about 0.5-m in diameter. The small size allows the infiltration rate to be computed as the difference of the cumulative rainfall and cumulative runoff without having to route water through a large plot. Difference infiltrometers were deployed in an area burned by the 2010 Fourmile Canyon Fire near Boulder, Colorado, USA, and data were collected during the summer of 2011. The difference infiltrometer demonstrated the capability to capture different magnitudes of infiltration rates and temporal variability associated with convective (high intensity, short duration) and cyclonic (low intensity, long duration) rainstorms. Data from the difference infiltrometer were used to estimate saturated hydraulic conductivity of soil affected by the heat from a wildfire. The difference infiltrometer is portable and can be deployed in rugged, steep terrain and does not require the transport of water, as many rainfall simulators require, because it uses natural rainfall. It can be used to assess infiltration models, determine runoff coefficients, identify rainfall depth or rainfall intensity thresholds to initiate runoff, estimate parameters for infiltration models, and compare remediation treatments on disturbed landscapes. The difference infiltrometer can be linked with other types of soil monitoring equipment in long-term studies for detecting temporal and spatial variability at multiple time scales and in nested designs where it can be linked to hillslope and basin-scale runoff responses.

  19. Assessing display variability in wild brown anoles Anolis sagrei using a mechanical lizard model

    Directory of Open Access Journals (Sweden)

    Sarah R. PARTAN, Peter OTOVIC, Virginia L. PRICE, Scott E. BROWN

    2011-04-01

    Full Text Available Signals used for species identity ought to be highly stereotyped so as to facilitate immediate recognition by conspecifics. It is surprising therefore to find variability in putative species signature displays. The brown anole Anolis sagrei has a high degree of variability in its signature bobbing display. In this study we collected descriptive data on variability in the temporal structure of wild brown anole bobbing patterns, finding that no two displays analyzed had the same temporal structure, and we also tested whether wild brown anoles prefer the signature display over an alternate display pattern by using mechanical robot playbacks in the field. As a response metric we assessed whether or not the lizards showed social responses (pushup, dewlap extension, or head-nod in response to the robotic presentations. We found that the lizards responded slightly more to the signature than to the alternate pattern, providing support for the idea that despite the variability seen in displays, the signature pattern is meaningful to them. We tested two other independent variables: speed of the display and elevation of the robot during its display, neither of which was significant. Dewlap extensions were given predominantly by adult males and were more likely to be given in the breeding season than the nonbreeding season. Pushups and head-nods were given equally by males and a combined class of females and juveniles, and were not seasonal. Head-nods increased after the robot turned off, suggesting that they may be used in a conversational turn-taking style during communication [Current Zoology 57 (2: 140–152, 2011].

  20. Heart rate variability to assess ventilatory thresholds in professional basketball players

    OpenAIRE

    Domingo Jesús Ramos-Campo; Jacobo A. Rubio-Arias; Vicente Ávila-Gandía; Cristian Marín-Pagán; Antonio Luque; Pedro E. Alcaraz

    2017-01-01

    Purpose: The aim of this study was to determine if heart rate variability (HRV) during incremental test could be used to estimate ventilatory threshold (VT) in professional basketball players, with sufficient precision to be used in their training. Furthermore, the second aim was to analyse the association between HRV and 3 methods of VT determination by gas analysis. Methods: Twenty-four professional basketball players (age: 23.4 ± 4.9 years; height: 195.4 ± 9.8 cm; body mass: 92.2 ± 11.9...

  1. Heart rate variability during pre-competition and competition periods in volleyball players

    OpenAIRE

    Podstawski Robert; Boraczyński Michał; Nowosielska-Swadźba Danuta; Zwolińska Danuta

    2014-01-01

    Study aim: Regular exercise training is thought to modify cardiac autonomic control. One of the body’s responses to training stimuli is heart rate variability (HRV). The use of HRV in the management of sport training is a common practice. The objective of the present study was to assess the impact of the physical activity level on HRV of 1st league national volleyball players prior to and during the competition period.

  2. Heart rate variability during pre-competition and competition periods in volleyball players

    Directory of Open Access Journals (Sweden)

    Podstawski Robert

    2014-01-01

    Full Text Available Study aim: Regular exercise training is thought to modify cardiac autonomic control. One of the body’s responses to training stimuli is heart rate variability (HRV. The use of HRV in the management of sport training is a common practice. The objective of the present study was to assess the impact of the physical activity level on HRV of 1st league national volleyball players prior to and during the competition period.

  3. Emotion regulation and trader expertise: heart rate variability on the trading floor

    OpenAIRE

    Fenton-O'Creevy, Mark; Lins, Jeffrey; Vohra, Shalini; Richards, Daniel; Davies, Gareth; Schaaff, Kristina

    2012-01-01

    We describe a psychophysiological study of the emotion regulation of investment bank traders. Building on work on the role of emotions in financial decision-making, we examine the relationship between market conditions, trader experience and emotion regulation whilst trading, as indexed by high frequency heart rate variability (HF HRV). We find a significant inverse relationship between HF HRV and market volatility and a positive relationship between HF HRV and trader experience. We argue tha...

  4. Changing Artificial Playback Speed and Real Movement Velocity Do Not Differentially Influence the Excitability of Primary Motor Cortex during Observation of a Repetitive Finger Movement

    Directory of Open Access Journals (Sweden)

    Takefumi Moriuchi

    2017-11-01

    Full Text Available Action observation studies have investigated whether changing the speed of the observed movement affects the action observation network. There are two types of speed-changing conditions; one involves “changes in actual movement velocity,” and the other is “manipulation of video speed.” Previous studies have investigated the effects of these conditions separately, but to date, no study has directly investigated the differences between the effects of these conditions. In the “movement velocity condition,” increased velocity is associated with increased muscle activity; however, this change of muscle activities is not shown in the “video speed condition.” Therefore, a difference in the results obtained under these conditions could be considered to reflect a difference in muscle activity of actor in the video. The aim of the present study was to investigate the effects of different speed-changing conditions and spontaneous movement tempo (SMT on the excitability of primary motor cortex (M1 during action observation, as assessed by motor-evoked potentials (MEPs amplitudes induced by transcranial magnetic stimulation (TMS. A total of 29 healthy subjects observed a video clip of a repetitive index or little finger abduction movement under seven different speed conditions. The video clip in the movement velocity condition showed repetitive finger abduction movements made in time with an auditory metronome, at frequencies of 0.5, 1, 2, and 3 Hz. In the video speed condition, playback of the 1-Hz movement velocity condition video clip was modified to show movement frequencies of 0.5, 2, or 3 Hz (Hz-Fake. TMS was applied at the time of maximal abduction and MEPs were recorded from two right-hand muscles. There were no differences in M1 excitability between the movement velocity and video speed conditions. Moreover, M1 excitability did not vary across the speed conditions for either presentation condition. Our findings suggest that changing

  5. Depression and heart rate variability in firefighters

    Directory of Open Access Journals (Sweden)

    Li-Mei Liao

    2014-07-01

    Full Text Available Introduction: Depression has been found to increase the risk of mortality in patients with coronary artery disease through a mechanism of changing cardiac autonomic tone which is reflected by alteration of heart rate variability indices. This study investigated whether such mechanism existed in firefighters who were at high risk of depression and sudden cardiac death. Methods and results: In total, 107 firefighters were recruited. All completed Beck Depression Inventory and underwent 24-h ambulatory electrocardiographic monitoring. The root-mean-square of successive differences, standard deviation of all normal-to-normal intervals index, and the percentage of differences between adjacent normal-to-normal intervals >50 ms were significantly lower in depressed than in non-depressed firefighters after controlling for hypertension, age, and body mass index (40.1 ± 18.8 vs 62.5 ± 77.4, p < 0.01; 63.0 ± 19.2 vs 72.1 ± 34.8, p < 0.01; 8.4 ± 7.2 vs 12.7 ± 10.9, p < 0.01, respectively. Conclusion: Decreased vagal tone is a possible mechanism linking depression and sudden cardiac death in firefighters.

  6. High spatial variability in biogeochemical rates and microbial communities across Louisiana salt marsh landscapes

    Science.gov (United States)

    Roberts, B. J.; Chelsky, A.; Bernhard, A. E.; Giblin, A. E.

    2017-12-01

    Salt marshes are important sites for retention and transformation of carbon and nutrients. Much of our current marsh biogeochemistry knowledge is based on sampling at times and in locations that are convenient, most often vegetated marsh platforms during low tide. Wetland loss rates are high in many coastal regions including Louisiana which has the highest loss rates in the US. This loss not only reduces total marsh area but also changes the relative allocation of subhabitats in the remaining marsh. Climate and other anthropogenic changes lead to further changes including inundation patterns, redox conditions, salinity regimes, and shifts in vegetation patterns across marsh landscapes. We present results from a series of studies examining biogeochemical rates, microbial communities, and soil properties along multiple edge to interior transects within Spartina alterniflora across the Louisiana coast; between expanding patches of Avicennia germinans and adjacent S. alterniflora marshes; in soils associated with the four most common Louisiana salt marsh plants species; and across six different marsh subhabitats. Spartina alterniflora marsh biogeochemistry and microbial populations display high spatial variability related to variability in soil properties which appear to be, at least in part, regulated by differences in elevation, hydrology, and redox conditions. Differences in rates between soils associated with different vegetation types were also related to soil properties with S. alterniflora soils often yielding the lowest rates. Biogeochemical process rates vary significantly across marsh subhabitats with individual process rates differing in their hotspot habitat(s) across the marsh. Distinct spatial patterns may influence the roles that marshes play in retaining and transforming nutrients in coastal regions and highlight the importance of incorporating spatial sampling when scaling up plot level measurements to landscape or regional scales.

  7. Genetic loci associated with heart rate variability and their effects on cardiac disease risk

    NARCIS (Netherlands)

    Nolte, Ilja M; Munoz, M Loretto; Tragante, Vinicius; Amare, Azmeraw T; Jansen, Rick; Vaez, Ahmad; von der Heyde, Benedikt; Avery, Christy L; Bis, Joshua C; Dierckx, Bram; van Dongen, Jenny; Gogarten, Stephanie M; Goyette, Philippe; Hernesniemi, Jussi; Huikari, Ville; Hwang, Shih-Jen; Jaju, Deepali; Kerr, Kathleen F; Kluttig, Alexander; Krijthe, Bouwe P; Kumar, Jitender; van der Laan, Sander W; Lyytikäinen, Leo-Pekka; Maihofer, Adam X; Minassian, Arpi; van der Most, Peter J; Müller-Nurasyid, Martina; Nivard, Michel; Salvi, Erika; Stewart, James D; Thayer, Julian F; Verweij, Niek; Wong, Andrew; Zabaneh, Delilah; Zafarmand, Mohammad H; Abdellaoui, Abdel; Albarwani, Sulayma; Albert, Christine; Alonso, Alvaro; Ashar, Foram; Auvinen, Juha; Axelsson, Tomas; Baker, Dewleen G; de Bakker, Paul I W; Barcella, Matteo; Bayoumi, Riad; Bieringa, Rob J; Boomsma, Dorret; Boucher, Gabrielle; Britton, Annie R; Christophersen, Ingrid; Dietrich, Andrea; Ehret, George B; Ellinor, Patrick T; Eskola, Markku; Felix, Janine F; Floras, John S; Franco, Oscar H; Friberg, Peter; Gademan, Maaike G J; Geyer, Mark A; Giedraitis, Vilmantas; Hartman, Catharina A; Hemerich, Daiane; Hofman, Albert; Hottenga, Jouke-Jan; Huikuri, Heikki; Hutri-Kähönen, Nina; Jouven, Xavier; Junttila, Juhani; Juonala, Markus; Kiviniemi, Antti M; Kors, Jan A.; Kumari, Meena; Kuznetsova, Tatiana; Laurie, Cathy C; Lefrandt, Joop D.; Li, Yong; Li, Yun; Liao, Duanping; Limacher, Marian C; Lin, Henry J; Lindgren, Cecilia M; Lubitz, Steven A; Mahajan, Anubha; McKnight, Barbara; Zu Schwabedissen, Henriette Meyer; Milaneschi, Yuri; Mononen, Nina; Morris, Andrew P; Nalls, Mike A; Navis, Gerjan; Neijts, Melanie; Nikus, Kjell; North, Kari E; O'Connor, Daniel T; Ormel, Johan; Perz, Siegfried; Peters, Annette; Psaty, Bruce M; Raitakari, Olli T; Risbrough, Victoria B; Sinner, Moritz F; Siscovick, David; Smit, Johannes H; Smith, Nicholas L; Soliman, Elsayed Z; Sotoodehnia, Nona; Staessen, Jan A; Stein, Phyllis K; Stilp, Adrienne M; Stolarz-Skrzypek, Katarzyna; Strauch, Konstantin; Sundström, Johan; Swenne, Cees A.; Syvänen, Ann-Christine; Tardif, Jean-Claude; Taylor, Kent D; Teumer, Alexander; Thornton, Timothy A; Tinker, Lesley E; Uitterlinden, André G; van Setten, Jessica; Voss, Andreas; Waldenberger, Melanie; Wilhelmsen, Kirk C; Willemsen, Gonneke; Wong, Quenna; Zhang, Zhu-Ming; Zonderman, Alan B; Cusi, Daniele; Evans, Michele K; Greiser, Halina K; van der Harst, Pim; Hassan, Mohammad; Ingelsson, Erik; Järvelin, Marjo-Riitta; Kääb, Stefan; Kähönen, Mika; Kivimaki, Mika; Kooperberg, Charles; Kuh, Diana; Lehtimäki, Terho; Lind, Lars; Nievergelt, Caroline M; O'Donnell, Chris J; Oldehinkel, Albertine J; Penninx, Brenda; Reiner, Alexander P; Riese, Harriëtte; Van Roon, Arie M.; Rioux, John D; Rotter, Jerome I; Sofer, Tamar; Stricker, Bruno H; Tiemeier, Henning; Vrijkotte, Tanja G M; Asselbergs, Folkert W; Brundel, Bianca J J M; Heckbert, Susan R; Whitsel, Eric A; den Hoed, Marcel; Snieder, Harold; de Geus, Eco J C

    2017-01-01

    Reduced cardiac vagal control reflected in low heart rate variability (HRV) is associated with greater risks for cardiac morbidity and mortality. In two-stage meta-analyses of genome-wide association studies for three HRV traits in up to 53,174 individuals of European ancestry, we detect 17

  8. A Longitudinal Study of Academic Progress Rate as a Result of Team and Institutional Variables at NCAA Division I Schools

    Science.gov (United States)

    Hale, Jimmie Edwin

    2014-01-01

    This study explained Academic Progress Rate (APR) levels and differences in APR (DAPR) with team and institutional variables. Team variables included team gender, sport profile, and squad size. Institutional variables included individual variables aggregated to the institutional level. The data analyzed in this study was derived from the National…

  9. Association between Anxiety Disorders and Heart Rate Variability in The Netherlands Study of Depression and Anxiety (NESDA)

    NARCIS (Netherlands)

    Licht, Carmilla M. M.; de Geus, Eco J. C.; van Dyck, Richard; Penninx, Brenda W. J. H.

    Objective: To determine whether patients with different types of anxiety disorder (panic disorder, social phobia, generalized anxiety disorder) have higher heart rate and lower heart rate variability compared with healthy controls in a sample that was sufficiently powered to examine the confounding

  10. How well can body size represent effects of the environment on demographic rates? Disentangling correlated explanatory variables.

    Science.gov (United States)

    Brooks, Mollie E; Mugabo, Marianne; Rodgers, Gwendolen M; Benton, Timothy G; Ozgul, Arpat

    2016-03-01

    Demographic rates are shaped by the interaction of past and current environments that individuals in a population experience. Past environments shape individual states via selection and plasticity, and fitness-related traits (e.g. individual size) are commonly used in demographic analyses to represent the effect of past environments on demographic rates. We quantified how well the size of individuals captures the effects of a population's past and current environments on demographic rates in a well-studied experimental system of soil mites. We decomposed these interrelated sources of variation with a novel method of multiple regression that is useful for understanding nonlinear relationships between responses and multicollinear explanatory variables. We graphically present the results using area-proportional Venn diagrams. Our novel method was developed by combining existing methods and expanding upon them. We showed that the strength of size as a proxy for the past environment varied widely among vital rates. For instance, in this organism with an income breeding life history, the environment had more effect on reproduction than individual size, but with substantial overlap indicating that size encompassed some of the effects of the past environment on fecundity. This demonstrates that the strength of size as a proxy for the past environment can vary widely among life-history processes within a species, and this variation should be taken into consideration in trait-based demographic or individual-based approaches that focus on phenotypic traits as state variables. Furthermore, the strength of a proxy will depend on what state variable(s) and what demographic rate is being examined; that is, different measures of body size (e.g. length, volume, mass, fat stores) will be better or worse proxies for various life-history processes. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

  11. Heart rate variability biofeedback: how and why does it work?

    Science.gov (United States)

    Lehrer, Paul M.; Gevirtz, Richard

    2014-01-01

    In recent years there has been substantial support for heart rate variability biofeedback (HRVB) as a treatment for a variety of disorders and for performance enhancement (Gevirtz, 2013). Since conditions as widely varied as asthma and depression seem to respond to this form of cardiorespiratory feedback training, the issue of possible mechanisms becomes more salient. The most supported possible mechanism is the strengthening of homeostasis in the baroreceptor (Vaschillo et al., 2002; Lehrer et al., 2003). Recently, the effect on the vagal afferent pathway to the frontal cortical areas has been proposed. In this article, we review these and other possible mechanisms that might explain the positive effects of HRVB. PMID:25101026

  12. Heart rate variability biofeedback: How and why does it work?

    Directory of Open Access Journals (Sweden)

    Paul M Lehrer

    2014-07-01

    Full Text Available In recent years there has been substantial support for Heart Rate Variability Biofeedback (HRVB as a treatment for a variety of disorders and for performance enhancement (Gevirtz, 2013. Since conditions as widely varied as asthma and depression seem to respond to this form of cardiorespiratory feedback training, the issue of possible mechanisms becomes more salient. The most supported possible mechanism is the strengthening of homeostasis in the barorecptor (Vashillo, et al, 2002; Lehrer, et al, 2003. Recently, the effect on the vagal afferent pathway to the frontal cortical areas has been proposed. In this article, we review these and other possible mechanisms that might explain the positive effects of HRVB.

  13. Analysis of heart rate variability and possibility of its utilization in psychology and psycho-physiology

    Directory of Open Access Journals (Sweden)

    Kovaleva A.V.

    2013-03-01

    Full Text Available Indices of heart rate variability are reliable and objective indicators of autonomic nervous systemtonus (of its sympathetic and parasympathetic divisions which in its turn reflect the changes in psycho-emotional state of a person, development of stress or any kind of tension. The purpose of this article was to describethe contemporary methods of objective study of a person’s functional state by the definition of autonomic regulation of heart rate and also the review of foreign studies which discuss the possibility of utilizing this method in psychology and psychophysiology. The review describes two approaches to the analysis of heart rate variability: temporal and frequency-response analyses. The indices used for temporal analysis include average duration of RR-intervalsand percentage of couples of RR-intervals, differing in more than 50ms(рNN50. The indices of frequency-response analysis included intensity of HF component, reflecting influences of parasympathetic outflow; intensity of LF component, reflecting sympathetic influences; intensity of VLF components; correlation of LF and HF waves, reflecting vegetal balance.

  14. Behaviour, heart rate, and heart rate variability in pigs exposed to novelty

    Directory of Open Access Journals (Sweden)

    Manja Zupan

    2016-03-01

    Full Text Available ABSTRACT In the present study, we investigated behavioural responses and determined parameters of heart rate variability (HRV to elucidate a relative activation of autonomic nervous system (ANS during baseline (10 min and in response to potentially stressful situations (10 min in two pig breeds and sexes. Gilts (n = 21 and barrows (n = 9 of the Landrace × Yorkshire (LY; n = 15 and Landrace/Yorkshire × Landrace/Duroc (LYLD; n = 15 breeds were subjected to a novel object test (NOT and a novel arena test (NAT. Basal ANS state differed in pigs across breeds but not sexes. Landrace × Yorkshire pigs had a significantly lower basal heart rate (HR and low-frequency band (LF with a higher root mean square of successive interbeat intervals (RMSSD and high-frequency band (HF than LYLD pigs. In the NOT, despite having similar cardiac responses, gilts had a longer duration of contact with a novel object, higher lying and standing duration, and a lower duration of walking compared with barrows. In the NAT, we found similar behaviour across sexes but a different degree of ANS state, with barrows having a significantly higher increase in LF/HF (power of the low frequency component divided by the power of the high-frequency band compared with gilts. Landrace/Yorkshire × Landrace/Duroc pigs showed longer duration of contact with a novel object in the NOT accompanied by less lying and standing than LY pigs in both tests. No difference in ANS activation between breeds was found in the NOT. In the NAT, HR increased more from baseline to testing in LY pigs than in LYLD pigs. There is a complex and often contradictory nature of relationships between behaviour and cardiac responses to novelty in pigs of different breeds and sexes.

  15. Music close to one's heart: heart rate variability with music, diagnostic with e-bra and smartphone

    Science.gov (United States)

    Hegde, Shantala; Kumar, Prashanth S.; Rai, Pratyush; Mathur, Gyanesh N.; Varadan, Vijay K.

    2012-04-01

    Music is a powerful elicitor of emotions. Emotions evoked by music, through autonomic correlates have been shown to cause significant modulation of parameters like heart rate and blood pressure. Consequently, Heart Rate Variability (HRV) analysis can be a powerful tool to explore evidence based therapeutic functions of music and conduct empirical studies on effect of musical emotion on heart function. However, there are limitations with current studies. HRV analysis has produced variable results to different emotions evoked via music, owing to variability in the methodology and the nature of music chosen. Therefore, a pragmatic understanding of HRV correlates of musical emotion in individuals listening to specifically chosen music whilst carrying out day to day routine activities is needed. In the present study, we aim to study HRV as a single case study, using an e-bra with nano-sensors to record heart rate in real time. The e-bra developed previously, has several salient features that make it conducive for this study- fully integrated garment, dry electrodes for easy use and unrestricted mobility. The study considers two experimental conditions:- First, HRV will be recorded when there is no music in the background and second, when music chosen by the researcher and by the subject is playing in the background.

  16. Is the algorithm used to process heart rate variability data clinically relevant? Analysis in male adolescents.

    Science.gov (United States)

    Soares, Antonio Henrique Germano; Farah, Breno Quintella; Cucato, Gabriel Grizzo; Bastos-Filho, Carmelo José Albanez; Christofaro, Diego Giulliano Destro; Vanderlei, Luiz Carlos Marques; Lima, Aluísio Henrique Rodrigues de Andrade; Ritti-Dias, Raphael Mendes

    2016-01-01

    To analyze whether the algorithm used for the heart rate variability assessment (fast Fourier transform versus autoregressive methods) influenced its association with cardiovascular risk factors in male adolescents. This cross-sectional study included 1,152 male adolescents (aged 14 to 19 years). The low frequency, high frequency components (absolute numbers and normalized units), low frequency/high frequency ratio, and total power of heart rate variability parameters were obtained using the fast Fourier transform and autoregressive methods, while the adolescents were resting in a supine position. All heart rate variability parameters calculated from both methods were different (padolescentes do gênero masculino. Estudo transversal, que incluiu 1.152 adolescentes do gênero masculino (14 a 19 anos). Componentes de baixa e alta frequência (absolutos e unidades normalizadas), razão componente de baixa frequência/componente de alta frequência e poder total da variabilidade da frequência cardíaca foram obtidos em repouso, na posição supina, usando os métodos transformada rápida de Fourier e autorregressivo. Todos os parâmetros da variabilidade da frequência cardíaca para ambos os métodos foram diferentes (padolescentes masculinos, mas essas diferenças não foram clinicamente significativas.

  17. On the problem of non-zero word error rates for fixed-rate error correction codes in continuous variable quantum key distribution

    International Nuclear Information System (INIS)

    Johnson, Sarah J; Ong, Lawrence; Shirvanimoghaddam, Mahyar; Lance, Andrew M; Symul, Thomas; Ralph, T C

    2017-01-01

    The maximum operational range of continuous variable quantum key distribution protocols has shown to be improved by employing high-efficiency forward error correction codes. Typically, the secret key rate model for such protocols is modified to account for the non-zero word error rate of such codes. In this paper, we demonstrate that this model is incorrect: firstly, we show by example that fixed-rate error correction codes, as currently defined, can exhibit efficiencies greater than unity. Secondly, we show that using this secret key model combined with greater than unity efficiency codes, implies that it is possible to achieve a positive secret key over an entanglement breaking channel—an impossible scenario. We then consider the secret key model from a post-selection perspective, and examine the implications for key rate if we constrain the forward error correction codes to operate at low word error rates. (paper)

  18. Heart rate variability and implication for sport concussion.

    Science.gov (United States)

    Bishop, Scott A; Dech, Ryan T; Guzik, Przemyslaw; Neary, J Patrick

    2017-11-16

    Finding sensitive and specific markers for sports-related concussion is both challenging and clinically important. Such biomarkers might be helpful in the management of patients with concussion (i.e. diagnosis, monitoring and risk prediction). Among many parameters, blood flow-pressure metrics and heart rate variability (HRV) have been used to gauge concussion outcomes. Reports on the relation between HRV and both acute and prolonged concussion recovery are conflicting. While some authors report on differences in the low-frequency (LF) component of HRV during postural manipulations and postexercise conditions, others observe no significant differences in various HRV measures. Despite the early success of using the HRV LF for concussion recovery, the interpretation of the LF is debated. Recent research suggests the LF power is a net effect of several intrinsic modulatory factors from both sympathetic and parasympathetic branches of the autonomic nervous system, vagally mediated baroreflex and even some respiratory influences at lower respiratory rate. There are only a few well-controlled concussion studies that specifically examine the contribution of the autonomic nervous system branches with HRV for concussion management. This study reviews the most recent HRV- concussion literature and the underlying HRV physiology. It also highlights cerebral blood flow studies related to concussion and the importance of multimodal assessment of various biological signals. It is hoped that a better understanding of the physiology behind HRV might generate cost-effective, repeatable and reliable protocols, all of which will improve the interpretation of HRV throughout concussion recovery. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  19. Association between smoking and heart rate variability among individuals with depression.

    Science.gov (United States)

    Harte, Christopher B; Liverant, Gabrielle I; Sloan, Denise M; Kamholz, Barbara W; Rosebrock, Laina E; Fava, Maurizio; Kaplan, Gary B

    2013-08-01

    Both depression and smoking have been independently associated with lower heart rate variability (HRV), suggesting dysregulation of cardiac autonomic function. However, no studies have systematically explored the effects of smoking on HRV among depressed patients. This study examined differences in HRV based on smoking status among depressed individuals. Electrophysiological data were examined among 77 adult outpatients without a history of myocardial infarction, who met criteria for major depressive disorder or dysthymia. Frequency domain [low frequency (LF), high frequency (HF), LF/HF ratio, respiratory sinus arrhythmia (RSA)] parameters of HRV, and heart rate and inter-beat interval (IBI) data were compared between depressed smokers (n = 34) and depressed nonsmokers (n = 44). After controlling for covariates, depressed smokers, compared to depressed nonsmokers, displayed significantly lower LF, HF, and RSA. Among depressed patients, smoking is associated with significantly lower HRV, indicating dysregulated autonomic modulation of the heart.

  20. Variability of excretion rates of 210Pb and 210Po of humans at environmental levels

    International Nuclear Information System (INIS)

    Spencer, H.; Holtzman, R.B.; Ilcewicz, F.H.; Kramer, L.

    1977-01-01

    Variability of the excretion rates of the nuclides 210 Pb and 210 Po at natural levels was studied in a group of samples collected from men maintained under the carefully controlled conditions of a metabolic ward. They consumed only the standard diet of the ward in which they had been resident for at least several months prior to this study. The mean urinary rates were about 0.1 to 0.5 pCi/day for both 210 Pb and 210 Po, while fecal rates ranged from 1 to 2.7 pCi/day for the two nuclides. For urinary 210 Pb the coefficients of variation (ratio of standard deviation to mean) for three subjects ranged from 19 to 45 percent for eight continuous 24-hr samples compared to 11 to 13 percent for subsequently collected multiday samples (4 to 9 days each) for each subject. However, the standard errors of the means for the one day collections were about equal to the standard deviations of the pooled samples. Similar variability was noted for the 210 Po data. Six day fecal collections from these time periods exhibited higher variabilities than did the urine, from about 12 percent to 50 percent for each of the nuclides. Multiday collections for 12 subjects showed mean coefficients of variation of about 16 percent for 210 Pb and 13 percent for the 210 Po for urine and 21 and 25 percent, respectively, in fecal collections. Since dietary intake was maintained fairly constant, excreta collections were carefully controlled, and the analytical precision was about 5 percent, these variabilities appear to be due to biological variations and are characteristic of the individuals studied. Some possible causes of these effects are discussed

  1. Heart Rate Variability Responses of Individuals With and Without Saline-Induced Obstructive Sleep Apnea.

    Science.gov (United States)

    Vena, Daniel; Bradley, T Douglas; Millar, Philip J; Floras, John S; Rubianto, Jonathan; Gavrilovic, Bojan; Perger, Elisa; Yadollahi, Azadeh

    2018-03-30

    Postoperative development of obstructive sleep apnea (OSA) has been attributed to the fluid overloaded state of patients during the postoperative period. In this context, alterations in cardiac autonomic regulation caused by OSA may explain the increased postoperative risk for adverse cardiovascular events. This study tests the hypothesis that individuals with fluid overload-induced OSA will experience autonomic dysregulation, compared to those without fluid overload-induced OSA. Twenty-one normotensive, nonobese (mean body mass index 24.5 kg/m2) males (mean age 37 years) underwent a sleep study. Participants were randomly assigned to infusion with saline during sleep either at the minimum rate (control) or as a bolus of 22 mL/kg body weight (intervention). Participants were blinded to the intervention and crossed over to the other study arm after 1 week. Measures of heart rate variability were calculated from electrocardiography recordings presaline and postsaline infusion in the intervention arm. Heart rate variability measures computed were: standard deviation of the RR interval; root mean square of successive differences; low-frequency, high-frequency, and total power; and the ratio of low-frequency to high-frequency power. Although presaline infusion values were similar, postsaline infusion values of the standard deviation of the RR interval and high-frequency power were lower in the group whose apnea-hypopnea index increased in response to saline infusion, compared to the group whose apnea-hypopnea index did not increase in response to saline infusion ( P variability, consistent with vagal withdrawal. Future work should explore autonomic dysregulation in the postoperative period and its association with adverse events. Copyright © 2018 American Academy of Sleep Medicine. All rights reserved.

  2. The effects of sustained manual pressure stimulation according to Vojta Therapy on heart rate variability.

    Science.gov (United States)

    Opavsky, Jaroslav; Slachtova, Martina; Kutin, Miroslav; Hok, Pavel; Uhlir, Petr; Opavska, Hana; Hlustik, Petr

    2018-05-23

    The physiotherapeutic technique of Vojta reflex locomotion is often accompanied by various autonomic activity changes and unpleasant sensations. It is unknown whether these effects are specific to Vojta Therapy. Therefore, the aim of this study was to compare changes in cardiac autonomic control after Vojta reflex locomotion stimulation and after an appropriate sham stimulation. A total of 28 young healthy adults (20.4 - 25.7 years) were enrolled in this single-blind randomized cross-over study. Participants underwent two modes of 20-minute sustained manual pressure stimulation on the surface of the foot on two separate visits. One mode used manual pressure on the lateral heel, i.e., in a zone employed in the Vojta Therapy (active stimulation). The other mode used pressure on the lateral ankle (control), in an area not included among the active zones used by Vojta Therapy and whose activation does not evoke manifestations of reflex locomotion. Autonomic nervous system activity was evaluated using spectral analysis of heart rate variability before and after the intervention. The active stimulation was perceived as more unpleasant than the control stimulation. Heart rate variability parameters demonstrated almost identical autonomic responses after both stimulation types, showing either modest increase in parasympathetic activity, or increased heart rate variability with similar contribution of parasympathetic and sympathetic activity. The results demonstrate changes of cardiac autonomic control in both active and control stimulation, without evidence for a significant difference between the two.

  3. Sensitivity, Specificity and Predictive Value of Heart Rate Variability Indices in Type 1 Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Anne Kastelianne França da Silva

    Full Text Available Abstract Background: Heart rate variability (HRV indices may detect autonomic changes with good diagnostic accuracy. Type diabetes mellitus (DM individuals may have changes in autonomic modulation; however, studies of this nature in this population are still scarce. Objective: To compare HRV indices between and assess their prognostic value by measurements of sensitivity, specificity and predictive values in young individuals with type 1 DM and healthy volunteers. Methods: In this cross-sectional study, physical and clinical assessment was performed in 39 young patients with type 1 DM and 43 young healthy controls. For HRV analysis, beat-to-beat heart rate variability was measured in dorsal decubitus, using a Polar S810i heart rate monitor, for 30 minutes. The following indices were calculated: SDNN, RMSSD, PNN50, TINN, RRTri, LF ms2, HF ms2, LF un, HF un, LF/HF, SD1, SD2, SD1/SD2, and ApEn. Results: Type 1 DM subjects showed a decrease in sympathetic and parasympathetic activities, and overall variability of autonomic nervous system. The RMSSD, SDNN, PNN50, LF ms2, HF ms2, RRTri, SD1 and SD2 indices showed greater diagnostic accuracy in discriminating diabetic from healthy individuals. Conclusion: Type 1 DM individuals have changes in autonomic modulation. The SDNN, RMSSD, PNN50, RRtri, LF ms2, HF ms2, SD1 and SD2 indices may be alternative tools to discriminate individuals with type 1 DM.

  4. [Heart rate variability and physical exercise. Current status].

    Science.gov (United States)

    Hottenrott, Kuno; Hoos, Olaf; Esperer, Hans Dieter

    2006-09-01

    Heart rate variability (HRV) has long been used in risk stratification for sudden cardiac death and diabetic autonomic neuropathy. In recent years, both time and frequency domain indices of HRV also gained increasing interest in sports and training sciences. In these fields, HRV is currently used for the noninvasive assessment of autonomic changes associated with short-term and long-term endurance exercise training in both leisure sports activity and high-performance training. Furthermore, HRV is being investigated as a diagnostic marker of overreaching and overtraining.A large body of evidence shows that, in healthy subjects and cardiovascular patients of all ages (up to an age of 70 years), regular aerobic training usually results in a significant improvement of overall as well as instantaneous HRV. These changes, which are accompanied by significant reductions in heart rates both at rest and during submaximal exercise, reflect an increase in autonomic efferent activity and a shift in favor of enhanced vagal modulation of the cardiac rhythm. Regular aerobic training of moderate volume and intensity over a minimum period of 3 months seems to be necessary to ensure these effects, which might be associated with a prognostic benefit regarding overall mortality.At present, available data does not allow for final conclusions with respect to the usefulness of traditional HRV indices in assessing an individual's exercise performance and monitoring training load. The discrepant results published so far are due to several factors including insufficient study size and design, and different HRV methods. Large-sized and prospectively designed studies are necessary for clarification. It also remains to be seen, whether the traditional HRV indices prove useful in the diagnosis of overreaching and overtraining. Preliminary results, though promising, need to be confirmed in larger cohorts.A basic problem in HRV analysis is nonstationarity of the heart rate signal, which holds

  5. Continuously variable rating: a new, simple and logical procedure to evaluate original scientific publications

    Directory of Open Access Journals (Sweden)

    Mauricio Rocha e Silva

    2011-01-01

    Full Text Available OBJECTIVE: Impact Factors (IF are widely used surrogates to evaluate single articles, in spite of known shortcomings imposed by cite distribution skewness. We quantify this asymmetry and propose a simple computer-based procedure for evaluating individual articles. METHOD: (a Analysis of symmetry. Journals clustered around nine Impact Factor points were selected from the medical ‘‘Subject Categories’’ in Journal Citation Reports 2010. Citable items published in 2008 were retrieved and ranked by granted citations over the Jan/2008 - Jun/2011 period. Frequency distribution of cites, normalized cumulative cites and absolute cites/decile were determined for each journal cluster. (b Positive Predictive Value. Three arbitrarily established evaluation classes were generated: LOW (1.33.9. Positive Predictive Value for journal clusters within each class range was estimated. (c Continuously Variable Rating. An alternative evaluation procedure is proposed to allow the rating of individually published articles in comparison to all articles published in the same journal within the same year of publication. The general guiding lines for the construction of a totally dedicated software program are delineated. RESULTS AND CONCLUSIONS: Skewness followed the Pareto Distribution for (1Variable Rating is shown to be a simple computer based procedure capable of accurately providing a valid rating for each article within the journal and time frame in which it was published.

  6. Variability of OH(3-1) and OH(6-2) emission altitude and volume emission rate from 2003 to 2011

    Science.gov (United States)

    Teiser, Georg; von Savigny, Christian

    2017-08-01

    In this study we report on variability in emission rate and centroid emission altitude of the OH(3-1) and OH(6-2) Meinel bands in the terrestrial nightglow based on spaceborne nightglow measurements with the SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) instrument on the Envisat satellite. The SCIAMACHY observations cover the time period from August 2002 to April 2012 and the nighttime observations used in this study are performed at 10:00 p.m. local solar time. Characterizing variability in OH emission altitude - particularly potential long-term variations - is important for an appropriate interpretation of ground-based OH rotational temperature measurements, because simultaneous observations of the vertical OH volume emission rate profile are usually not available for these measurements. OH emission altitude and vertically integrated emission rate time series with daily resolution for the OH(3-1) band and monthly resolution for the OH(6-2) band were analyzed using a standard multilinear regression approach allowing for seasonal variations, QBO-effects (Quasi-Biennial Oscillation), solar cycle (SC) variability and a linear long-term trend. The analysis focuses on low latitudes, where SCIAMACHY nighttime observations are available all year. The dominant sources of variability for both OH emission rate and altitude are the semi-annual and annual variations, with emission rate and altitude being highly anti-correlated. There is some evidence for a 11-year solar cycle signature in the vertically integrated emission rate and in the centroid emission altitude of both the OH(3-1) and OH(6-2) bands.

  7. Heart rate variability in sleep-related migraine without aura.

    Science.gov (United States)

    Vollono, Catello; Gnoni, Valentina; Testani, Elisa; Dittoni, Serena; Losurdo, Anna; Colicchio, Salvatore; Di Blasi, Chiara; Mazza, Salvatore; Farina, Benedetto; Della Marca, Giacomo

    2013-07-15

    This is an observational study aimed to investigate the activity of autonomic nervous system during sleep in patients with sleep-related migraine. Eight consecutive migraineurs without aura were enrolled (6 women and 2 men), aged 30 to 62 years (mean 48.1 ± 9.3 years). Inclusion criteria were: high frequency of attacks (> 5 per month) and occurrence of more than 75% of the attacks during sleep causing an awakening. Patients were compared with a control group of 55 healthy subjects (23 men and 32 women, mean age 54.2 ± 13.0 years), and with a further control group of 8 age- and gender-matched healthy controls. Patient and controls underwent polysomnography and heart rate variability analysis. A significant reduction of the LF/HF ratio during N2 and N3 sleep stages was observed in migraineurs compared with controls. No differences in sleep macrostructure were observed; cyclic alternating pattern (CAP) time and CAP rate were lower in migraineurs than in controls. These findings indicate a peculiar modification of the autonomic balance during sleep in sleep-related migraine. The reduction of LF/HF ratio in NREM sleep was observed in controls, but it was quantitatively much more evident in migraineurs. Changes in LF/HF could be consequent to an autonomic unbalance which could manifest selectively (or alternatively become more evident) during sleep. These findings, together with the reduction in CAP rate, could be an expression of reduced arousability during sleep in patients with sleep-related migraine. The simultaneous involvement of the autonomic, arousal, and pain systems might suggest involvement of the hypothalamic pathways.

  8. Correlation structures in short-term variabilities of stock indices and exchange rates

    Science.gov (United States)

    Nakamura, Tomomichi; Small, Michael

    2007-09-01

    Financial data usually show irregular fluctuations and some trends. We investigate whether there are correlation structures in short-term variabilities (irregular fluctuations) among financial data from the viewpoint of deterministic dynamical systems. Our method is based on the small-shuffle surrogate method. The data we use are daily closing price of Standard & Poor's 500 and the volume, and daily foreign exchange rates, Euro/US Dollar (USD), British Pound/USD and Japanese Yen/USD. We found that these data are not independent.

  9. Computational procedure of optimal inventory model involving controllable backorder rate and variable lead time with defective units

    Science.gov (United States)

    Lee, Wen-Chuan; Wu, Jong-Wuu; Tsou, Hsin-Hui; Lei, Chia-Ling

    2012-10-01

    This article considers that the number of defective units in an arrival order is a binominal random variable. We derive a modified mixture inventory model with backorders and lost sales, in which the order quantity and lead time are decision variables. In our studies, we also assume that the backorder rate is dependent on the length of lead time through the amount of shortages and let the backorder rate be a control variable. In addition, we assume that the lead time demand follows a mixture of normal distributions, and then relax the assumption about the form of the mixture of distribution functions of the lead time demand and apply the minimax distribution free procedure to solve the problem. Furthermore, we develop an algorithm procedure to obtain the optimal ordering strategy for each case. Finally, three numerical examples are also given to illustrate the results.

  10. Features of the heart rate variability in the perioperative period after adenotomy in children

    Directory of Open Access Journals (Sweden)

    Михайло Борисович Пушкар

    2015-03-01

    Full Text Available Aim. Study course of perioperative period after adenotomy in children in different ways of general anesthesia by examining indicators of heart rate variability and efficacy of postoperative analgesia.Materials and methods. To study included 70 children aged from 6 to 8 years, which was held adenotomy. Patients were divided into 3 groups: group I (n = 28 - operated under conditions of intravenous anesthesia based on propofol combined with fentanyl; group II (n=23 – operated under conditions of inhalation anesthesia by sevoflurane in combination with fentanyl and analginum; group III (n=19 – operated under conditions of intravenous anesthesia based on thiopental sodium combined with fentanyl. Differences were considered significant at p <0.05 using Student t-test.Results. Indicators of heart rate variability indicated that in the extubation stage in all groups of patients revealed high activity of the sympathetic tone with the trend of decline in the morning after surgery. Statistically higher activity of the sympathetic part of the autonomic nervous system was in patients of group III - 1 hour after surgery compared with patients groups I and II (p <0,001 and p <0,01, respectively. After 1 hour after surgery on the scales "Faces" and "Oucher" scores indicated that the child "a little hurt" in all groups of patients In the dynamics of observation in all groups tended to reduce the intensity of pain. An interpretation of scores on the FLACC scale indicated that patients in both groups felt comfortable.Conclusions. It was found that in patients in all groups there are changes in the nervous regulation of heart rate variability, characterized by increased activity of the sympathetic division of the autonomic nervous system. Postoperative anesthesia by 10 mg / kg ibuprofen provides effective analgesia

  11. Relative influence of age, resting heart rate and sedentary life style in short-term analysis of heart rate variability

    Directory of Open Access Journals (Sweden)

    E.R. Migliaro

    2001-04-01

    Full Text Available In order to assess the relative influence of age, resting heart rate (HR and sedentary life style, heart rate variability (HRV was studied in two different groups. The young group (YG consisted of 9 sedentary subjects aged 15 to 20 years (YG-S and of 9 nonsedentary volunteers (YG-NS also aged 15 to 20. The elderly sedentary group (ESG consisted of 16 sedentary subjects aged 39 to 82 years. HRV was assessed using a short-term procedure (5 min. R-R variability was calculated in the time-domain by means of the root mean square successive differences. Frequency-domain HRV was evaluated by power spectrum analysis considering high frequency and low frequency bands. In the YG the effort tolerance was ranked in a bicycle stress test. HR was similar for both groups while ESG showed a reduced HRV compared with YG. Within each group, HRV displayed a negative correlation with HR. Although YG-NS had better effort tolerance than YG-S, their HR and HRV were not significantly different. We conclude that HRV is reduced with increasing HR or age, regardless of life style. The results obtained in our short-term study agree with others of longer duration by showing that age and HR are the main determinants of HRV. Our results do not support the idea that changes in HRV are related to regular physical activity.

  12. Relative influence of age, resting heart rate and sedentary life style in short-term analysis of heart rate variability.

    Science.gov (United States)

    Migliaro, E R; Contreras, P; Bech, S; Etxagibel, A; Castro, M; Ricca, R; Vicente, K

    2001-04-01

    In order to assess the relative influence of age, resting heart rate (HR) and sedentary life style, heart rate variability (HRV) was studied in two different groups. The young group (YG) consisted of 9 sedentary subjects aged 15 to 20 years (YG-S) and of 9 nonsedentary volunteers (YG-NS) also aged 15 to 20. The elderly sedentary group (ESG) consisted of 16 sedentary subjects aged 39 to 82 years. HRV was assessed using a short-term procedure (5 min). R-R variability was calculated in the time-domain by means of the root mean square successive differences. Frequency-domain HRV was evaluated by power spectrum analysis considering high frequency and low frequency bands. In the YG the effort tolerance was ranked in a bicycle stress test. HR was similar for both groups while ESG showed a reduced HRV compared with YG. Within each group, HRV displayed a negative correlation with HR. Although YG-NS had better effort tolerance than YG-S, their HR and HRV were not significantly different. We conclude that HRV is reduced with increasing HR or age, regardless of life style. The results obtained in our short-term study agree with others of longer duration by showing that age and HR are the main determinants of HRV. Our results do not support the idea that changes in HRV are related to regular physical activity.

  13. Changes of heart rate variability and prefrontal oxygenation during Tai Chi practice versus arm ergometer cycling.

    Science.gov (United States)

    Lu, Xi; Hui-Chan, Christina Wan-Ying; Tsang, William Wai-Nam

    2016-11-01

    [Purpose] Exercise has been shown to improve cardiovascular fitness and cognitive function. Whether the inclusion of mind over exercise would increase parasympathetic control of the heart and brain activities more than general exercise at a similar intensity is not known. The aim of this study was to compare the effects of Tai Chi (mind-body exercise) versus arm ergometer cycling (body-focused exercise) on the heart rate variability and prefrontal oxygenation level. [Subjects and Methods] A Tai Chi master was invited to perform Tai Chi and arm ergometer cycling with similar exercise intensity on two separate days. Heart rate variability and prefrontal oxyhemoglobin levels were measured continuously by a RR recorder and near-infrared spectroscopy, respectively. [Results] During Tai Chi exercise, spectral analysis of heart rate variability demonstrated a higher high-frequency power as well as a lower low-frequency/high-frequency ratio than during ergometer cycling, suggesting increased parasympathetic and decreased sympathetic control of the heart. Also, prefrontal oxyhemoglobin and total hemoglobin levels were higher than those during arm ergometer exercise. [Conclusion] These findings suggest that increased parasympathetic control of the heart and prefrontal activities may be associated with Tai Chi practice. Having a "mind" component in Tai Chi could be more beneficial for older adults' cardiac health and cognitive function than body-focused ergometer cycling.

  14. An Overview of Heart Rate Variability Metrics and Norms

    Directory of Open Access Journals (Sweden)

    Fred Shaffer

    2017-09-01

    Full Text Available Healthy biological systems exhibit complex patterns of variability that can be described by mathematical chaos. Heart rate variability (HRV consists of changes in the time intervals between consecutive heartbeats called interbeat intervals (IBIs. A healthy heart is not a metronome. The oscillations of a healthy heart are complex and constantly changing, which allow the cardiovascular system to rapidly adjust to sudden physical and psychological challenges to homeostasis. This article briefly reviews current perspectives on the mechanisms that generate 24 h, short-term (~5 min, and ultra-short-term (<5 min HRV, the importance of HRV, and its implications for health and performance. The authors provide an overview of widely-used HRV time-domain, frequency-domain, and non-linear metrics. Time-domain indices quantify the amount of HRV observed during monitoring periods that may range from ~2 min to 24 h. Frequency-domain values calculate the absolute or relative amount of signal energy within component bands. Non-linear measurements quantify the unpredictability and complexity of a series of IBIs. The authors survey published normative values for clinical, healthy, and optimal performance populations. They stress the importance of measurement context, including recording period length, subject age, and sex, on baseline HRV values. They caution that 24 h, short-term, and ultra-short-term normative values are not interchangeable. They encourage professionals to supplement published norms with findings from their own specialized populations. Finally, the authors provide an overview of HRV assessment strategies for clinical and optimal performance interventions.

  15. Heart rate variability affected by radiofrequency electromagnetic field in adolescent students.

    Science.gov (United States)

    Misek, Jakub; Belyaev, Igor; Jakusova, Viera; Tonhajzerova, Ingrid; Barabas, Jan; Jakus, Jan

    2018-05-01

    This study examines the possible effect of radiofrequency (RF) electromagnetic fields (EMF) on the autonomic nervous system (ANS). The effect of RF EMF on ANS activity was studied by measuring heart rate variability (HRV) during ortho-clinostatic test (i.e., transition from lying to standing and back) in 46 healthy grammar school students. A 1788 MHz pulsed wave with intensity of 54 ± 1.6 V/m was applied intermittently for 18 min in each trial. Maximum specific absorption rate (SAR 10 ) value was determined to 0.405 W/kg. We also measured the respiration rate and estimated a subjective perception of EMF exposure. RF exposure decreased heart rate of subjects in a lying position, while no such change was seen in standing students. After exposure while lying, a rise in high frequency band of HRV and root Mean Square of the Successive Differences was observed, which indicated an increase in parasympathetic nerve activity. Tympanic temperature and skin temperature were measured showing no heating under RF exposure. No RF effect on respiration rate was observed. None of the tested subjects were able to distinguish real exposure from sham exposure when queried at the end of the trial. In conclusion, short-term RF EMF exposure of students in a lying position during the ortho-clinostatic test affected ANS with significant increase in parasympathetic nerve activity compared to sham exposed group. Bioelectromagnetics. 39:277-288, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  16. Intratesticular and subcutaneous lidocaine alters the intraoperative haemodynamic responses and heart rate variability in male cats undergoing castration

    NARCIS (Netherlands)

    Moldal, E.R.; Eriksen, T.; Kirpensteijn, J.; Nødtvedt, A.; Kristensen, A.T.; Sparta, F.M.; Haga, H.A.

    2013-01-01

    Abstract OBJECTIVE: To evaluate the usefulness of intratesticular and subcutaneous lidocaine in alleviating the intraoperative nociceptive response to castration, measured by pulse rate (PR) and mean arterial pressure (MAP), and to test the applicability of heart rate variability (HRV) analysis in

  17. HEART RATE VARIABILITY AND BODY COMPOSITION AS VO2MAX DETERMINANTS

    Directory of Open Access Journals (Sweden)

    Henry Humberto León-Ariza

    Full Text Available ABSTRACT Introduction: The maximum oxygen consumption (VO2max is the gold standard in the cardiorespiratory endurance assessment. Objective: This study aimed to develop a mathematical model that contains variables to determine the VO2max of sedentary people. Methods: Twenty participants (10 men and 10 women with a mean age of 19.8±1.77 years were included. For each participant, body composition (percentage of fat and muscle, heart rate variability (HRV at rest (supine and standing, and VO2max were evaluated through an indirect test on a cycloergometer. A multivariate linear regression model was developed from the data obtained, and the model assumptions were verified. Results: Using the data obtained, including percentage of fat (F, percentage of muscle (M, percentage of power at very low frequency (VLF, α-value of the detrended fluctuation analysis (DFAα1, heart rate (HR in the resting standing position, and age of the participants, a model was established for men, which was expressed as VO2max = 4.216 + (Age*0.153 + (F*0.110 - (M*0.053 - (VLF*0.649 - (DFAα1*2.441 - (HR*0.014, with R2 = 0.965 and standard error = 0.146 L/min. For women, the model was expressed as VO2max = 1.947 - (Age*0.047 + (F*0.024 + (M*0.054 + (VLF*1.949 - (DFAα1*0.424 - (HR*0.019, with R2 = 0.987 and standard error = 0.077 L/min. Conclusion: The obtained model demonstrated the influence exerted by body composition, the autonomic nervous system, and age in the prediction of VO2max.

  18. The validity of the BioForce Heart Rate Variability System and the use of heart rate variability and recovery to determine the fitness levels of a cohort of university-level rugby players / Christo Alfonzo Bisschoff

    OpenAIRE

    Bisschoff, Christo Alfonzo

    2013-01-01

    The potential to track changes in training status and fitness levels of especially team sport participants by making use of more time efficient and accessible methods such as heart rate variability (HRV) and heart rate recovery (HRR) cannot be overlooked and needs to be considered. However, studies that have investigated this aspect in team sport participants are scarce. It is against this background that the main objectives of this study were firstly, to determine the relation...

  19. Analysis of Autonomic Nervous System Functional Age and Heart Rate Variability in Mine Workers

    Directory of Open Access Journals (Sweden)

    Vasicko T

    2016-04-01

    Full Text Available Introduction: Heavy working conditions and many unpropitious factors influencing workers health participate in development of various health disorders, among other autonomic cardiovascular regulation malfunction. The aim of this study is to draw a comparison of autonomic nervous system functional age and heart rate variability changes between workers with and without mining occupational exposure.

  20. Playing a violent television game affects heart rate variability.

    Science.gov (United States)

    Ivarsson, Malena; Anderson, Martin; Akerstedt, Torbjörn; Lindblad, Frank

    2009-01-01

    To investigate how playing a violent/nonviolent television game during the evening affects sympathetic and parasympathetic reactions during and after playing as well as sleep quality during the night after playing. In total, 19 boys, 12-15 years of age, played television games on two occasions in their homes and participated once without gaming. Heart rate, heart rate variability (HRV) and physical activity were measured during gaming/participating and the night to follow using a portable combined heart rate and movement sensor. A sleep diary and questionnaires about gaming experiences and session-specific experiences were filled in. Criteria for Selection of Games: Violent game involves/rewards direct physical violence (no handguns) against another person, and nonviolent game involves/rewards no violence; same game design ('third-person game'); conducted in the same manner; no differences concerning motor activity; similar sound and light effects; no sexual content, violence against women or racial overtones. During violent (vs. nonviolent) gaming, there was significantly higher activity of the very low frequency component of the HRV and total power. During the night after playing, very low frequency, low frequency and high frequency components were significantly higher during the violent (vs. nonviolent) condition, just as total power. There were no significant differences between the three conditions (violent/nonviolent/no gaming) with respect to an index reflecting subjectively perceived sleep difficulties. Nor was there any difference between violent and nonviolent condition for any single sleep item. Violent gaming induces different autonomic responses in boys compared to nonviolent gaming--during playing and during the following night--suggesting different emotional responses. Subjectively perceived sleep quality is not influenced after a single gaming experience. Future studies should address the development of the autonomic balance after gaming over longer

  1. A brief review and clinical application of heart rate variability biofeedback in sports, exercise, and rehabilitation medicine.

    Science.gov (United States)

    Prinsloo, Gabriell E; Rauch, H G Laurie; Derman, Wayne E

    2014-05-01

    An important component of the effective management of chronic noncommunicable disease is the assessment and management of psychosocial stress. The measurement and modulation of heart rate variability (HRV) may be valuable in this regard. To describe the measurement and physiological control of HRV; to describe the impact of psychosocial stress on cardiovascular disease, metabolic syndrome, and chronic respiratory disease, and the relationship between these diseases and changes in HRV; and to describe the influence of biofeedback and exercise on HRV and the use of HRV biofeedback in the management of chronic disease. The PubMed, Medline, and Embase databases were searched (up to August 2013). Additional articles were obtained from the reference lists of relevant articles and reviews. Articles were individually selected for further review based on the quality and focus of the study, and the population studied. Heart rate variability is reduced in stress and in many chronic diseases, and may even predict the development and prognosis of some diseases. Heart rate variability can be increased with both exercise and biofeedback. Although the research on the effect of exercise is conflicting, there is evidence that aerobic training may increase HRV and cardiac vagal tone both in healthy individuals and in patients with disease. Heart rate variability biofeedback is also an effective method of increasing HRV and cardiac vagal tone, and has been shown to decrease stress and reduce the morbidity and mortality of disease. The assessment and management of psychosocial stress is a challenging but important component of effective comprehensive lifestyle interventions for the management of noncommunicable disease. It is, therefore, important for the sports and exercise physician to have an understanding of the therapeutic use of HRV modulation, both in the reduction of stress and in the management of chronic disease.

  2. The role of heart rate variability in sports physiology.

    Science.gov (United States)

    Dong, Jin-Guo

    2016-05-01

    Heart rate variability (HRV) is a relevant marker reflecting cardiac modulation by sympathetic and vagal components of the autonomic nervous system (ANS). Although the clinical application of HRV is mainly associated with the prediction of sudden cardiac death and assessing cardiovascular and metabolic illness progression, recent observations have suggested its applicability to physical exercise training. HRV is becoming one of the most useful tools for tracking the time course of training adaptation/maladaptation of athletes and in setting the optimal training loads leading to improved performances. However, little is known regarding the role of HRV and the internal effects of physical exercise on an athlete, which may be useful in designing fitness programs ensuring sufficient training load that may correspond with the specific ability of the athlete. In this review, we offer a comprehensive assessment of investigations concerning the interrelation between HRV and ANS, and examine how the application of HRV to physical exercise may play a role in sports physiology.

  3. Effect of propranolol on heart rate variability in hyperthyroidism.

    Science.gov (United States)

    Tankeu, Aurel T; Azabji-Kenfack, Marcel; Nganou, Chris-Nadège; Ngassam, Eliane; Kuate-Mfeukeu, Liliane; Mba, Camille; Dehayem, Mesmin Y; Mbanya, Jean-Claude; Sobngwi, Eugene

    2018-02-22

    We aimed to determine the effect of propanolol on heart rate variability (HRV) in hyperthyroidism before antithyroid treatment. This was a before and after study, on ten patients presenting overt hyperthyroidism naïve to treatment. In each patient, a resting electrocardiogram was done followed by estimation of cardiac autonomic dysfunction during five maneuvers (Ewing battery tests). Long term HRV measurement was done using 24 h ambulatory electrocardiographic recording. This automatically provided estimation of HRV using SDNN and RMSSD index, LF, HF, and HF/LF ratio. After baseline investigations, 40 mg of propanolol was given twice a day for 3 days and same parameters were measured after 72 h of treatment. Our patients were aged 40 ± 10 years. Propanolol significantly reduced RR and HR interval (669 ms vs 763 ms and 91 vs 79 bpm; p hyperthyroidism. Trial registration NCT03393728 "Retrospectively registered".

  4. Heart rate variability analysis with the R package RHRV

    CERN Document Server

    García Martínez, Constantino Antonio; Vila, Xosé A; Lado Touriño, María José; Rodríguez-Liñares, Leandro; Rodríguez Presedo, Jesús María; Méndez Penín, Arturo José

    2017-01-01

    This book introduces readers to the basic concepts of Heart Rate Variability (HRV) and its most important analysis algorithms using a hands-on approach based on the open-source RHRV software. HRV refers to the variation over time of the intervals between consecutive heartbeats. Despite its apparent simplicity, HRV is one of the most important markers of the autonomic nervous system activity and it has been recognized as a useful predictor of several pathologies. The book discusses all the basic HRV topics, including the physiological contributions to HRV, clinical applications, HRV data acquisition, HRV data manipulation and HRV analysis using time-domain, frequency-domain, time-frequency, nonlinear and fractal techniques. Detailed examples based on real data sets are provided throughout the book to illustrate the algorithms and discuss the physiological implications of the results. Offering a comprehensive guide to analyzing beat information with RHRV, the book is intended for masters and Ph.D. students in v...

  5. Precision for Smallholder Farmers: A Small-Scale-Tailored Variable Rate Fertilizer Application Kit

    Directory of Open Access Journals (Sweden)

    Jelle Van Loon

    2018-03-01

    Full Text Available Precision agriculture technology at the hands of smallholder farmers in the developing world is often deemed far-fetched. Low-resource farmers, however, are the most susceptible to negative changes in the environment. Providing these farmers with the right tools to mitigate adversity and to gain greater control of the production process could unlock their potential and support rural communities to meet the increasing global food demand. In this study, a real-time variable rate fertilizer application system was developed and tested as an add-on kit to conventional farm machinery. In the context of low investment costs for smallholder farmers, high user-friendliness and easy installment were the main concerns for the system to be viable. The system used nitrogen (N-sensors to assess the plant nutrient status on the spot and subsequently adjust the amount of fertilizer deposited according to the plant’s needs. Test bench trials showed that the add-on kit performed well with basic operations, but more precision is required. Variability between N-sensors and metering systems, combined with power fluctuations, created inaccuracies in the resulting application rate. Nevertheless, this work is a stepping stone towards catalyzing the elaboration of more cutting-edge precision solutions to support small-scale farmers to become successful, high producing agro-entrepreneurs.

  6. Low vagally-mediated heart rate variability and increased susceptibility to ventricular arrhythmias in rats bred for high anxiety.

    Science.gov (United States)

    Carnevali, Luca; Trombini, Mimosa; Graiani, Gallia; Madeddu, Denise; Quaini, Federico; Landgraf, Rainer; Neumann, Inga D; Nalivaiko, Eugene; Sgoifo, Andrea

    2014-04-10

    In humans, there is a documented association between anxiety disorders and cardiovascular disease. Putative underlying mechanisms may include an impairment of the autonomic nervous system control of cardiac function. The primary objective of the present study was to characterize cardiac autonomic modulation and susceptibility to arrhythmias in genetic lines of rats that differ largely in their anxiety level. To reach this goal, electrocardiographic recordings were performed in high-anxiety behavior (HAB, n=10) and low-anxiety behavior (LAB, n=10) rats at rest, during stressful stimuli and under autonomic pharmacological manipulations, and analyzed by means of time- and frequency-domain indexes of heart rate variability. During resting conditions, HAB rats displayed a reduced heart rate variability, mostly in terms of lower parasympathetic (vagal) modulation compared to LAB rats. In HAB rats, this relatively low cardiac vagal control was associated with smaller heart rate responsiveness to acute stressors compared to LAB counterparts. In addition, beta-adrenergic pharmacological stimulation induced a larger incidence of ventricular tachyarrhythmias in HABs compared to LABs. At sacrifice, a moderate increase in heart-body weight ratio was observed in HAB rats. We conclude that high levels of anxiety-related behavior in rats are associated with signs of i) impaired autonomic modulation of heart rate (low vagally-mediated heart rate variability), ii) poor adaptive heart rate responsiveness to stressful stimuli, iii) increased arrhythmia susceptibility, and iv) cardiac hypertrophy. These results highlight the utility of the HAB/LAB model for investigating the mechanistic basis of the comorbidity between anxiety disorders and cardiovascular disease. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Daily heart rate variability of Paralympic gold medallist swimmers: A 17-week investigation

    OpenAIRE

    Edmonds, Rohan; Leicht, Anthony; McKean, Mark; Burkett, Brendan

    2015-01-01

    Objectives: Heart rate variability (HRV) can be a simple, non-invasive method of gauging cardiac autonomic nervous system fluctuations across periodised training workloads and taper in elite athlete populations. The purpose of these three case studies was to examine daily cardiac autonomic variations in Paralympic athletes leading in to the Paralympic games. Methods: Three Paralympic gold medallist swimmers were monitored daily for their resting HRV over a 17-week monitoring period leading...

  8. Smart Device for the Determination of Heart Rate Variability in Real Time

    Directory of Open Access Journals (Sweden)

    David Naranjo-Hernández

    2017-01-01

    Full Text Available This work presents a first approach to the design, development, and implementation of a smart device for the real-time measurement and detection of alterations in heart rate variability (HRV. The smart device follows a modular design scheme, which consists of an electrocardiogram (ECG signal acquisition module, a processing module and a wireless communications module. From five-minute ECG signals, the processing module algorithms perform a spectral estimation of the HRV. The experimental results demonstrate the viability of the smart device and the proposed processing algorithms.

  9. Exercise training improves heart rate variability after methamphetamine dependency.

    Science.gov (United States)

    Dolezal, Brett Andrew; Chudzynski, Joy; Dickerson, Daniel; Mooney, Larissa; Rawson, Richard A; Garfinkel, Alan; Cooper, Christopher B

    2014-06-01

    Heart rate variability (HRV) reflects a healthy autonomic nervous system and is increased with physical training. Methamphetamine dependence (MD) causes autonomic dysfunction and diminished HRV. We compared recently abstinent methamphetamine-dependent participants with age-matched, drug-free controls (DF) and also investigated whether HRV can be improved with exercise training in the methamphetamine-dependent participants. In 50 participants (MD = 28; DF = 22), resting heart rate (HR; R-R intervals) was recorded over 5 min while seated using a monitor affixed to a chest strap. Previously reported time domain (SDNN, RMSSD, pNN50) and frequency domain (LFnu, HFnu, LF/HF) parameters of HRV were calculated with customized software. MD were randomized to thrice-weekly exercise training (ME = 14) or equal attention without training (MC = 14) over 8 wk. Groups were compared using paired and unpaired t-tests. Statistical significance was set at P ≤ 0.05. Participant characteristics were matched between groups (mean ± SD): age = 33 ± 6 yr; body mass = 82.7 ± 12 kg, body mass index = 26.8 ± 4.1 kg·min. Compared with DF, the MD group had significantly higher resting HR (P HRV indices were similar between ME and MC groups. However, after training, the ME group significantly (all P HRV, based on several conventional indices, was diminished in recently abstinent, methamphetamine-dependent individuals. Moreover, physical training yielded a marked increase in HRV, representing increased vagal modulation or improved autonomic balance.

  10. Heart Rate Variability during Social Interactions in Children with and without Psychopathology: A Meta-Analysis

    Science.gov (United States)

    Shahrestani, Sara; Stewart, Elizabeth M.; Quintana, Daniel S.; Hickie, Ian B.; Guastella, Adam J.

    2014-01-01

    Background: The inability to regulate autonomic activity during social interactions is believed to contribute to social and emotional dysregulation in children. Research has employed heart rate variability (HRV) during both socially engaging and socially disengaging dyadic tasks between children and adults to assess this. Methods: We conducted a…

  11. Changes in cortisol release and heart rate and heart rate variability during the initial training of 3-year-old sport horses.

    Science.gov (United States)

    Schmidt, Alice; Aurich, Jörg; Möstl, Erich; Müller, Jürgen; Aurich, Christine

    2010-09-01

    Based on cortisol release, a variety of situations to which domestic horses are exposed have been classified as stressors but studies on the stress during equestrian training are limited. In the present study, Warmblood stallions (n=9) and mares (n=7) were followed through a 9 respective 12-week initial training program in order to determine potentially stressful training steps. Salivary cortisol concentrations, beat-to-beat (RR) interval and heart rate variability (HRV) were determined. The HRV variables standard deviation of the RR interval (SDRR), RMSSD (root mean square of successive RR differences) and the geometric means standard deviation 1 (SD1) and 2 (SD2) were calculated. Nearly each training unit was associated with an increase in salivary cortisol concentrations (pHRV variables SDRR, RMSSD and SD1 decreased in response to training and lowest values were reached during mounting of a rider (pHRV variables increased again. In contrast, SD2 increased with the beginning of lunging (p<0.05) and no changes in response to mounting were detectable. In conclusion, initial training is a stressor for horses. The most pronounced reaction occurred in response to mounting by a rider, a situation resembling a potentially lethal threat under natural conditions. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  12. Risk Assessment of Diabetes Mellitus by Chaotic Globals to Heart Rate Variability via Six Power Spectra

    Directory of Open Access Journals (Sweden)

    Garner David M.

    2017-09-01

    Full Text Available Background: The priniciple objective here is to analyze cardiovascular dynamics in diabetic subjects by actions related to heart rate variability (HRV. The correlation of chaotic globals is vital to evaluate the probability of dynamical diseases.

  13. Heart rate variability and heart rate turbulence in patients with polycystic ovary syndrome.

    Science.gov (United States)

    Özkeçeci, Gülay; Ünlü, Bekir Serdar; Dursun, Hüseyin; Akçi, Önder; Köken, Gülengül; Onrat, Ersel; Avşar, Alaettin

    2016-05-01

    Cardiac autonomic dysfunction may develop in patients with polycystic ovary syndrome (PCOS). Heart rate variability (HRV) and heart rate turbulence (HRT) are used in assessing cardiac autonomic functions. The goal of this study was to compare the cardiac autonomic functions in patients with PCOS and healthy controls. To our knowledge, this is the first study evaluating cardiac autonomic functions in patients with PCOS with respect to both HRV and HRT. Twenty-three patients with PCOS (mean age 22.8±3.9 years) and 25 healthy female volunteers who were matched for age and body mass index (BMI) (mean age 23.5±6.2 years) were enrolled in this as case-control study. Twenty-four hour ambulatory electrocardiogram recordings of all participants were taken using Pathfinder software. The time domain parameters of HRV and HRT, including turbulence onset (TO) and turbulence slope, were calculated. Diagnosis of PCOS was made with physical and laboratory findings of hirsutism or biochemical hyperandrogenism and chronic anovulation. Diabetes mellitus, other hormon disorders or hormon therapy, pregnancy, atrial fibrilation, obesite, chronic diseases, disorders of the autonomic nervous system, a history of drug use affecting the autonomic nervous system were excluded. There were no significant differences in HRV and HRT parameters between the two groups. Cardiovascular risk factors, such as BMI, blood pressure, fasting blood glucose, and lipid parameters, were also similar. Triangular index measure of HRV was negatively correlated with high density lipoprotein cholesterol levels (r=-0.47, p<0.05), while age and BMI were significantly correlated with TO (r=0.31 and 0.47, respectively; p<0.05 for all). Cardiac autonomic functions were not found to be altered in patients with PCOS in comparison with healthy controls. These results may be explained with the absence of concomitant cardiovascular risk factors with the patients being in the early stage of the disease.

  14. A Golay complementary TS-based symbol synchronization scheme in variable rate LDPC-coded MB-OFDM UWBoF system

    Science.gov (United States)

    He, Jing; Wen, Xuejie; Chen, Ming; Chen, Lin

    2015-09-01

    In this paper, a Golay complementary training sequence (TS)-based symbol synchronization scheme is proposed and experimentally demonstrated in multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband over fiber (UWBoF) system with a variable rate low-density parity-check (LDPC) code. Meanwhile, the coding gain and spectral efficiency in the variable rate LDPC-coded MB-OFDM UWBoF system are investigated. By utilizing the non-periodic auto-correlation property of the Golay complementary pair, the start point of LDPC-coded MB-OFDM UWB signal can be estimated accurately. After 100 km standard single-mode fiber (SSMF) transmission, at the bit error rate of 1×10-3, the experimental results show that the short block length 64QAM-LDPC coding provides a coding gain of 4.5 dB, 3.8 dB and 2.9 dB for a code rate of 62.5%, 75% and 87.5%, respectively.

  15. MEDEX 2015: Heart Rate Variability Predicts Development of Acute Mountain Sickness.

    Science.gov (United States)

    Sutherland, Angus; Freer, Joseph; Evans, Laura; Dolci, Alberto; Crotti, Matteo; Macdonald, Jamie Hugo

    2017-09-01

    Sutherland, Angus, Joseph Freer, Laura Evans, Alberto Dolci, Matteo Crotti, and Jamie Hugo Macdonald. MEDEX 2015: Heart rate variability predicts development of acute mountain sickness. High Alt Med Biol. 18: 199-208, 2017. Acute mountain sickness (AMS) develops when the body fails to acclimatize to atmospheric changes at altitude. Preascent prediction of susceptibility to AMS would be a useful tool to prevent subsequent harm. Changes to peripheral oxygen saturation (SpO 2 ) on hypoxic exposure have previously been shown to be of poor predictive value. Heart rate variability (HRV) has shown promise in the early prediction of AMS, but its use pre-expedition has not previously been investigated. We aimed to determine whether pre- and intraexpedition HRV assessment could predict susceptibility to AMS at high altitude with better diagnostic accuracy than SpO 2 . Forty-four healthy volunteers undertook an expedition in the Nepali Himalaya to >5000 m. SpO 2 and HRV parameters were recorded at rest in normoxia and in a normobaric hypoxic chamber before the expedition. On the expedition HRV parameters and SpO 2 were collected again at 3841 m. A daily Lake Louise Score was obtained to assess AMS symptomology. Low frequency/high frequency (LF/HF) ratio in normoxia (cutpoint ≤2.28 a.u.) and LF following 15 minutes of exposure to normobaric hypoxia had moderate (area under the curve ≥0.8) diagnostic accuracy. LF/HF ratio in normoxia had the highest sensitivity (85%) and specificity (88%) for predicting AMS on subsequent ascent to altitude. In contrast, pre-expedition SpO 2 measurements had poor (area under the curve <0.7) diagnostic accuracy and inferior sensitivity and specificity. Pre-ascent measurement of HRV in normoxia was found to be of better diagnostic accuracy for AMS prediction than all measures of HRV in hypoxia, and better than peripheral oxygen saturation monitoring.

  16. Discrete rate and variable power adaptation for underlay cognitive networks

    KAUST Repository

    Abdallah, Mohamed M.

    2010-01-01

    We consider the problem of maximizing the average spectral efficiency of a secondary link in underlay cognitive networks. In particular, we consider the network setting whereby the secondary transmitter employs discrete rate and variable power adaptation under the constraints of maximum average transmit power and maximum average interference power allowed at the primary receiver due to the existence of an interference link between the secondary transmitter and the primary receiver. We first find the optimal discrete rates assuming a predetermined partitioning of the signal-to-noise ratio (SNR) of both the secondary and interference links. We then present an iterative algorithm for finding a suboptimal partitioning of the SNR of the interference link assuming a fixed partitioning of the SNR of secondary link selected for the case where no interference link exists. Our numerical results show that the average spectral efficiency attained by using the iterative algorithm is close to that achieved by the computationally extensive exhaustive search method for the case of Rayleigh fading channels. In addition, our simulations show that selecting the optimal partitioning of the SNR of the secondary link assuming no interference link exists still achieves the maximum average spectral efficiency for the case where the average interference constraint is considered. © 2010 IEEE.

  17. Heart rate variability among caregivers of chronically bedridden patients

    Directory of Open Access Journals (Sweden)

    Amrith Pakkala

    2013-01-01

    Full Text Available Background: Caregivers of chronically bedridden patients are likely to suffer from mental and physical exhaustion leading to stress. This is important in view of the prevailing socioeconomic as well as the healthcare system available in a developing country like India. Therefore, the present study is designed to measure heart rate variability (HRV among this special group of population who give care to long-term bedridden patients. Materials and Methods: Fifteen female subjects were enrolled from among attendants of patients admitted with an immediate history of a cerebrovascular accident with locomotor deficits, who required constant care. They were free from any type of physical and mental health issues, nonsmokers and nonaddicts. Each care giver was subjected to HRV analysis on three occasions: The first record was performed in the 1 st week of their arrival in the hospital as caregivers. The second observation was recorded after 3 months of caregiving. The final HRV analysis was done after 6 months of care giving. Two types of parameters were analyzed: Time domain and frequency domain. Statistical analysis was done using paired t-test. Results: Both the HRV parameters: Time and frequency domain, showed decreased values during the 3 rd and 6 th month recording as compared to the 1 st week recording. The decrease is much more during the 6 th month recording as compared to the 3 rd month recording. Statistically significant decrease is observed in mean RR interval, heart rate, very low frequency (VLF, and LF only when the 1 st week recording is compared with the 3 rd month recording, but when the 1 st week recording was compared with the 6 th month recording significant decrease was found in mean RR interval and heart rate. Conclusion: Subjects involved in taking care of chronically ill bedridden patients are likely to undergo a lot of physical and mental stress, thus affecting their autonomic status. HRV analysis using short term

  18. Comparing low frequency heart rate variability and preejection period: Two sides of a different coin.

    NARCIS (Netherlands)

    Goedhart, A.D.; Willemsen, G.; Houtveen, J.H.; Boomsma, D.I.; de Geus, E.J.C.

    2008-01-01

    It has been hypothesized that the ratio of heart rate variability in the low- (LF) and high- (HF) frequency bands may capture variation in cardiac sympathetic control. Here we tested the temporal stability of the LF/HF ratio in 24-h ambulatory recordings and compared this ratio to the preejection

  19. Does geographical variability influence five-year MACCE rates in the multicentre SYNTAX revascularisation trial?

    Science.gov (United States)

    Roy, Andrew K; Chevalier, Bernard; Lefèvre, Thierry; Louvard, Yves; Segurado, Ricardo; Sawaya, Fadi; Spaziano, Marco; Neylon, Antoinette; Serruys, Patrick A; Dawkins, Keith D; Kappetein, Arie Pieter; Mohr, Friedrich-Wilhelm; Colombo, Antonio; Feldman, Ted; Morice, Marie-Claude

    2017-09-20

    The use of multiple geographical sites for randomised cardiovascular trials may lead to important heterogeneity in treatment effects. This study aimed to determine whether treatment effects from different geographical recruitment regions impacted significantly on five-year MACCE rates in the SYNTAX trial. Five-year SYNTAX results (n=1,800) were analysed for geographical variability by site and country for the effect of treatment (CABG vs. PCI) on MACCE rates. Fixed, random, and linear mixed models were used to test clinical covariate effects, such as diabetes, lesion characteristics, and procedural factors. Comparing five-year MACCE rates, the pooled odds ratio (OR) between study sites was 0.58 (95% CI: 0.47-0.71), and countries 0.59 (95% CI: 0.45-0.73). By homogeneity testing, no individual site (X2=93.8, p=0.051) or country differences (X2=25.7, p=0.080) were observed. For random effects models, the intraclass correlation was minimal (ICC site=5.1%, ICC country=1.5%, p<0.001), indicating minimal geographical heterogeneity, with a hazard ratio of 0.70 (95% CI: 0.59-0.83). Baseline risk (smoking, diabetes, PAD) did not influence regional five-year MACCE outcomes (ICC 1.3%-5.2%), nor did revascularisation of the left main vs. three-vessel disease (p=0.241), across site or country subgroups. For CABG patients, the number of arterial (p=0.49) or venous (p=0.38) conduits used also made no difference. Geographic variability has no significant treatment effect on MACCE rates at five years. These findings highlight the generalisability of the five-year outcomes of the SYNTAX study.

  20. A Meta-analysis on Resting State High-frequency Heart Rate Variability in Bulimia Nervosa.

    Science.gov (United States)

    Peschel, Stephanie K V; Feeling, Nicole R; Vögele, Claus; Kaess, Michael; Thayer, Julian F; Koenig, Julian

    2016-09-01

    Autonomic nervous system function is altered in eating disorders. We aimed to quantify differences in resting state vagal activity, indexed by high-frequency heart rate variability comparing patients with bulimia nervosa (BN) and healthy controls. A systematic search of the literature to identify studies eligible for inclusion and meta-analytical methods were applied. Meta-regression was used to identify potential covariates. Eight studies reporting measures of resting high-frequency heart rate variability in individuals with BN (n = 137) and controls (n = 190) were included. Random-effects meta-analysis revealed a sizeable main effect (Z = 2.22, p = .03; Hedge's g = 0.52, 95% CI [0.06;0.98]) indicating higher resting state vagal activity in individuals with BN. Meta-regression showed that body mass index and medication intake are significant covariates. Findings suggest higher vagal activity in BN at rest, particularly in unmedicated samples with lower body mass index. Potential mechanisms underlying these findings and implications for routine clinical care are discussed. Copyright © 2016 John Wiley & Sons, Ltd and Eating Disorders Association. Copyright © 2016 John Wiley & Sons, Ltd and Eating Disorders Association.

  1. Effects of spinal manipulation and myofascial techniques on heart rate variability: A systematic review.

    Science.gov (United States)

    Amoroso Borges, Bruno Luis; Bortolazzo, Gustavo Luiz; Neto, Hugo Pasin

    2018-01-01

    The analysis of heart rate variability is important to the investigation of stimuli from the autonomic nervous system. Osteopathy is a form of treatment that can influence this system in healthy individuals as well as those with a disorder or disease. The aim of the present study was to perform a systematic review of the literature regarding the effect of spinal manipulation and myofascial techniques on heart rate variability. Searches were performed of the Pubmed, Scielo, Lilacs, PEDro, Ibesco, Cochrane and Scopus databases for relevant studies. The PEDro scale was used to assess the methodological quality of each study selected. A total of 505 articles were retrieved during the initial search. After an analysis of the abstracts, nine studies were selected for the present review. Based on the findings, osteopathy exerts an influence on the autonomic nervous system depending on the stimulation site and type. A greater parasympathetic response was found when stimulation was performed in the cervical and lumbar regions, whereas a greater sympathetic response was found when stimulation was performed in the thoracic region. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Hydrocortisone at stress-associated concentrations helps maintain human heart rate variability during subsequent endotoxin challenge.

    Science.gov (United States)

    Rassias, Athos J; Guyre, Paul M; Yeager, Mark P

    2011-12-01

    We evaluated the differential impact of stress-associated vs high pharmacologic concentrations of hydrocortisone pretreatment on heart rate variability (HRV) during a subsequent systemic inflammatory stimulus. Healthy volunteers were randomized to receive placebo (Control) and hydrocortisone at 1.5 μg/kg per minute (STRESS) or at 3.0 μg/kg per minute (PHARM) as a 6-hour infusion. The STRESS dose was chosen to replicate the condition of physiologic adrenal cortical output during acute systemic stress. The PHARM dose was chosen to induce a supraphysiologic concentration of cortisol. The next day, all subjects received 2 ng/kg Escherichia coli endotoxin (lipopolysaccharide). Heart rate variability was analyzed with the statistic approximate entropy (ApEn). A lower ApEn correlates with decreased HRV. At the 3-hour nadir, the decrease in ApEn in the STRESS group was significantly less compared to placebo (P statistically different. We also found that the maximal decrease in ApEn preceded maximal increase in heart rate in all groups. The decrease in R-R interval was maximal at 4 hours, whereas the ApEn nadir was 1 hour earlier at 3 hours. Pretreatment with a stress dose of hydrocortisone but not a higher pharmacologic dose maintained a significantly higher ApEn after endotoxin exposure when compared to a placebo. In addition, decreases in ApEn preceded increases in heart rate. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Evaluation of Heart Rate Variability by means of Laser Doppler Vibrometry measurements

    International Nuclear Information System (INIS)

    Cosoli, G; Casacanditella, L; Tomasini, EP; Scalise, L

    2015-01-01

    Heart Rate Variability (HRV) analysis aims to study the physiological variability of the Heart Rate (HR), which is related to the health conditions of the subject. HRV is assessed measuring heart periods (HP) on a time window of >5 minutes (1)-(2). HPs are determined from signals of different nature: electrocardiogram (ECG), photoplethysmogram (PPG), phonocardiogram (PCG) or vibrocardiogram (VCG) (3)-(4)-(5). The fundamental aspect is the identification of a feature in each heartbeat that allows to accurately compute cardiac periods (such as R peaks in ECG), in order to make possible the measurement of all the typical HRV evaluations on those intervals. VCG is a non-contact technique (4), very favourable in medicine, which detects the vibrations on the skin surface (e.g. on the carotid artery) resulting from vascular blood motion consequent to electrical signal (ECG).In this paper, we propose the use of VCG for the measurement of a signal related to HRV and the use of a novel algorithm based on signal geometry (7) to detect signal peaks, in order to accurately determine cardiac periods and the Poincare plot (9)-(10). The results reported are comparable to the ones reached with the gold standard (ECG) and in literature (3)-(5). We report mean values of HP of 832±54 ms and 832±55 ms by means of ECG and VCG, respectively. Moreover, this algorithm allow us to identify particular features of ECG and VCG signals, so that in the future we will be able to evaluate specific correlations between the two. (paper)

  4. Deficient maternal zinc intake-but not folate-is associated with lower fetal heart rate variability.

    Science.gov (United States)

    Spann, Marisa N; Smerling, Jennifer; Gustafsson, Hanna; Foss, Sophie; Altemus, Margaret; Monk, Catherine

    2015-03-01

    Few studies of maternal prenatal diet and child development examine micronutrient status in relation to fetal assessment. Twenty-four-hour dietary recall of zinc and folate and 20min of fetal heart rate were collected from 3rd trimester pregnant adolescents. Deficient zinc was associated with less fetal heart rate variability. Deficient folate had no associations with HRV. Neither deficient zinc nor deficient folate was related to fetal heart rate. These findings, from naturalistic observation, are consistent with emerging data on prenatal zinc supplementation using a randomized control design. Taken together, the findings suggest that maternal prenatal zinc intake is an important and novel factor for understanding child ANS development. Copyright © 2015. Published by Elsevier Ireland Ltd.

  5. Deficient maternal zinc intake—but not folate—is associated with lower fetal heart rate variability

    Science.gov (United States)

    Spann, Marisa N.; Smerling, Jennifer; Gustafsson, Hanna; Foss, Sophie; Altemus, Margaret; Monk, Catherine

    2015-01-01

    Objective Few studies of maternal prenatal diet and child development examine micronutrient status in relation to fetal assessment. Methods Twenty-four-hour dietary recall of zinc and folate and 20min of fetal heart rate were collected from 3rd trimester pregnant adolescents. Results Deficient zinc was associated with less fetal heart rate variability. Deficient folate had no associations with HRV. Neither deficient zinc nor deficient folate was related to fetal heart rate. Conclusions These findings, from naturalistic observation, are consistent with emerging data on prenatal zinc supplementation using a randomized control design. Practical Implication Taken together, the findings suggest that maternal prenatal zinc intake is an important and novel factor for understanding child ANS development. PMID:25658874

  6. Altered Heart Rate Variability During Gaming in Internet Gaming Disorder.

    Science.gov (United States)

    Lee, Deokjong; Hong, Sung Jun; Jung, Young-Chul; Park, Jinsick; Kim, In Young; Namkoong, Kee

    2018-04-01

    Internet gaming disorder (IGD) is characterized by addiction to online gaming and reduced executive control, particularly when individuals are exposed to gaming-related cues. Executive control can be measured as vagally mediated heart rate variability (HRV), which corresponds to variability in the time interval between heart beats. In this study, we investigated whether individuals with IGD have altered HRV while playing online games. We hypothesized that while gaming, individuals with IGD would exhibit phasic suppression of vagally mediated HRV, which would reflect executive control dysfunction during game play. To test this, we measured the changes of HRV when young males with IGD were engaged in real-time online gaming. The changes of HRV were associated with the severity of IGD assessed by self-reports and prefrontal gray matter volume (GMV) calculated by voxel-based morphometry. We included 23 IGD subjects and 18 controls in our analyses. Changes in HRV were not statistically different between IGD subjects and controls. Within the IGD group, however, subjects showed significant decreases in high-frequency (HF) HRV during gaming. Furthermore, the degree of decrease correlated with IGD severity and prefrontal GMV. Importantly, this phasic suppression of HF-HRV in response to gaming did not occur in control subjects. In conclusion, young males with IGD showed an altered HRV response while playing an online game, reflecting their difficulties in executive control over gaming. The dynamics between executive control and reward seeking may be out of balance during game play in IGD.

  7. Physical activity, mindfulness meditation, or heart rate variability biofeedback for stress reduction: a randomized controlled trial

    NARCIS (Netherlands)

    van der Zwan, J.E.; de Vente, W.; Huizink, A.C.; Bögels, S.M.; de Bruin, E.I.

    2015-01-01

    In contemporary western societies stress is highly prevalent, therefore the need for stress-reducing methods is great. This randomized controlled trial compared the efficacy of self-help physical activity (PA), mindfulness meditation (MM), and heart rate variability biofeedback (HRV-BF) in reducing

  8. An exploratory clinical study to determine the utility of heart rate variability analysis in the assessment of dosha imbalance

    Directory of Open Access Journals (Sweden)

    P. Ram Manohar

    2018-04-01

    Full Text Available The present study is a comparison of the data of spectral analysis of heart rate variability with clinical evaluation of pathological state of doshas. The calculated cardiointervalography values are combined into three integral indexes, which according to the authors' opinion reflect the influence on heart rhythm of vata, pitta and kapha, the regulation systems of the body known as doshas in Ayurveda. Seven gross dosha imbalances were assessed to test the agreement between the two methods in this study. Heart Rate Variability (HRV spectral data was collected from 42 participants to make the comparison with the clinical assessment of dosha imbalance. Clinical method of dosha assessment and method of calculating integral indexes by cardiointervalography data showed substantial agreement by Kappa coefficient statistic (k = 0.78 in assessment of gross dosha imbalance. The results of the data generated from this pilot study warrant further studies to rigorously validate the algorithms of HRV analysis in understanding dosha imbalance in Ayurvedic clinical practice and research settings. Keywords: Heart rate variability, Ayurveda, Spectral analysis

  9. Determination of heart rate variability with an electronic stethoscope.

    Science.gov (United States)

    Kamran, Haroon; Naggar, Isaac; Oniyuke, Francisca; Palomeque, Mercy; Chokshi, Priya; Salciccioli, Louis; Stewart, Mark; Lazar, Jason M

    2013-02-01

    Heart rate variability (HRV) is widely used to characterize cardiac autonomic function by measuring beat-to-beat alterations in heart rate. Decreased HRV has been found predictive of worse cardiovascular (CV) outcomes. HRV is determined from time intervals between QRS complexes recorded by electrocardiography (ECG) for several minutes to 24 h. Although cardiac auscultation with a stethoscope is performed routinely on patients, the human ear cannot detect heart sound time intervals. The electronic stethoscope digitally processes heart sounds, from which cardiac time intervals can be obtained. Accordingly, the objective of this study was to determine the feasibility of obtaining HRV from electronically recorded heart sounds. We prospectively studied 50 subjects with and without CV risk factors/disease and simultaneously recorded single lead ECG and heart sounds for 2 min. Time and frequency measures of HRV were calculated from R-R and S1-S1 intervals and were compared using intra-class correlation coefficients (ICC). The majority of the indices were strongly correlated (ICC 0.73-1.0), while the remaining indices were moderately correlated (ICC 0.56-0.63). In conclusion, we found HRV measures determined from S1-S1 are in agreement with those determined by single lead ECG, and we demonstrate and discuss differences in the measures in detail. In addition to characterizing cardiac murmurs and time intervals, the electronic stethoscope holds promise as a convenient low-cost tool to determine HRV in the hospital and outpatient settings as a practical extension of the physical examination.

  10. Influence of Climate Variability on US Regional Homicide Rates

    Science.gov (United States)

    Harp, R. D.; Karnauskas, K. B.

    2017-12-01

    Recent studies have found consistent evidence of a relationship between temperature and criminal behavior. However, despite agreement in the overall relationship, little progress has been made in distinguishing between two proposed explanatory theories. The General Affective Aggression Model (GAAM) suggests that high temperatures create periods of higher heat stress that enhance individual aggressiveness, whereas the Routine Activities Theory (RAT) theorizes that individuals are more likely to be outdoors interacting with others during periods of pleasant weather with a resulting increase in both interpersonal interactions and victim availability. Further, few studies have considered this relationship within the context of climate change in a quantitative manner. In an effort to distinguish between the two theories, and to examine the statistical relationships on a broader spatial scale than previously, we combined data from the Supplementary Homicide Report (SHR—compiled by the Federal Bureau of Investigation) and the North American Regional Reanalysis (NARR—compiled by the National Centers for Environmental Protection, a branch of the National Oceanic and Atmospheric Administration). US homicide data described by the SHR was compared with seven relevant observed climate variables (temperature, dew point, relative humidity, accumulated precipitation, accumulated snowfall, snow cover, and snow depth) provided by the NARR atmospheric reanalysis. Relationships between homicide rates and climate variables, as well as reveal regional spatial patterns will be presented and discussed, along with the implications due to future climate change. This research lays the groundwork for the refinement of estimates of an oft-overlooked climate change impact, which has previously been estimated to cause an additional 22,000 murders between 2010 and 2099, including providing important constraints for empirical models of future violent crime incidences in the face of global

  11. Nitrogen replenishment using variable rate application technique in a small hand-harvested pear orchard

    Energy Technology Data Exchange (ETDEWEB)

    Vatsanidou, A.; Nanos, G.D.; Fountas, S.; Baras, J.; Castrignano, A.; Gemtos, T.A.

    2017-07-01

    Precision agriculture is a management approach for sustainable agriculture. It can be applied even in small fields. It aims to optimize inputs, improve profits, and reduce adverse environmental impacts. In this study, a series of measurements were conducted over three growing seasons to assess variability in a 0.55 ha pear orchard located in central Greece. Soil ECa was measured using EM38 sensor, while soil samples were taken from a grid 17 × 8 m and analysed for texture, pH, P, K, Mg, CaCO3, and organic matter content. Data analysis indicated that most of the nutrients were at sufficient levels. Soil and yield maps showed considerable variability while fruit quality presented small variations across the orchard. Yield fluctuations were observed, possibly due to climatic conditions. Prescription maps were developed for nitrogen variable rate application (VRA) for two years based on the replacement of the nutrients removed by the crop. VRA application resulted in 56% and 50% reduction of N fertiliser compared to uniform application.

  12. Nitrogen replenishment using variable rate application technique in a small hand-harvested pear orchard

    International Nuclear Information System (INIS)

    Vatsanidou, A.; Nanos, G.D.; Fountas, S.; Baras, J.; Castrignano, A.; Gemtos, T.A.

    2017-01-01

    Precision agriculture is a management approach for sustainable agriculture. It can be applied even in small fields. It aims to optimize inputs, improve profits, and reduce adverse environmental impacts. In this study, a series of measurements were conducted over three growing seasons to assess variability in a 0.55 ha pear orchard located in central Greece. Soil ECa was measured using EM38 sensor, while soil samples were taken from a grid 17 × 8 m and analysed for texture, pH, P, K, Mg, CaCO3, and organic matter content. Data analysis indicated that most of the nutrients were at sufficient levels. Soil and yield maps showed considerable variability while fruit quality presented small variations across the orchard. Yield fluctuations were observed, possibly due to climatic conditions. Prescription maps were developed for nitrogen variable rate application (VRA) for two years based on the replacement of the nutrients removed by the crop. VRA application resulted in 56% and 50% reduction of N fertiliser compared to uniform application.

  13. Nitrogen replenishment using variable rate application technique in a small hand-harvested pear orchard

    Directory of Open Access Journals (Sweden)

    Anna Vatsanidou

    2018-02-01

    Full Text Available Precision agriculture is a management approach for sustainable agriculture. It can be applied even in small fields. It aims to optimize inputs, improve profits, and reduce adverse environmental impacts. In this study, a series of measurements were conducted over three growing seasons to assess variability in a 0.55 ha pear orchard located in central Greece. Soil ECa was measured using EM38 sensor, while soil samples were taken from a grid 17 × 8 m and analysed for texture, pH, P, K, Mg, CaCO3, and organic matter content. Data analysis indicated that most of the nutrients were at sufficient levels. Soil and yield maps showed considerable variability while fruit quality presented small variations across the orchard. Yield fluctuations were observed, possibly due to climatic conditions. Prescription maps were developed for nitrogen variable rate application (VRA for two years based on the replacement of the nutrients removed by the crop. VRA application resulted in 56% and 50% reduction of N fertiliser compared to uniform application.

  14. Dynamics of spectral components of heart rate variability during changes in autonomic balance

    DEFF Research Database (Denmark)

    Højgaard, M V; Holstein-Rathlou, N H; Agner, E

    1998-01-01

    Frequency domain analysis of heart rate variability (HRV) has been proposed as a semiquantitative method for assessing activities in the autonomic nervous system. We examined whether absolute powers, normalized powers, and the low frequency-to-high frequency ratio (LF/HF) derived from the HRV power...... spectrum could detect shifts in autonomic balance in a setting with low sympathetic nervous tone. Healthy subjects were examined for 3 h in the supine position during 1) control conditions (n = 12), 2) acute beta-blockade (n = 11), and 3) chronic beta-blockade (n = 10). Heart rate fell during the first 40...... min of the control session (72 +/- 2 to 64 +/- 2 beats/min; P powers of all spectral areas rose during the first 60 min in all three settings, more so with beta-blockade (P

  15. Chaos Synchronization Using Adaptive Dynamic Neural Network Controller with Variable Learning Rates

    Directory of Open Access Journals (Sweden)

    Chih-Hong Kao

    2011-01-01

    Full Text Available This paper addresses the synchronization of chaotic gyros with unknown parameters and external disturbance via an adaptive dynamic neural network control (ADNNC system. The proposed ADNNC system is composed of a neural controller and a smooth compensator. The neural controller uses a dynamic RBF (DRBF network to online approximate an ideal controller. The DRBF network can create new hidden neurons online if the input data falls outside the hidden layer and prune the insignificant hidden neurons online if the hidden neuron is inappropriate. The smooth compensator is designed to compensate for the approximation error between the neural controller and the ideal controller. Moreover, the variable learning rates of the parameter adaptation laws are derived based on a discrete-type Lyapunov function to speed up the convergence rate of the tracking error. Finally, the simulation results which verified the chaotic behavior of two nonlinear identical chaotic gyros can be synchronized using the proposed ADNNC scheme.

  16. A longitudinal study in youth of heart rate variability at rest and in response to stress

    NARCIS (Netherlands)

    Li, Zhibin; Snieder, Harold; Su, Shaoyong; Ding, Xiuhua; Thayer, Julian F.; Treiber, Frank A.; Wang, Xiaoling

    Background: Few longitudinal studies have examined ethnic and sex differences, predictors and tracking stabilities of heart rate variability (HRV) at rest and in response to stress in youths and young adults. Methods: Two evaluations were performed approximately 1.5 years apart on 399 youths and

  17. Endothelial dysfunction and reduced heart rate variability in patients with metabolic syndrome

    Directory of Open Access Journals (Sweden)

    Elena Nikolaevna Smirnova

    2018-03-01

    Full Text Available According to experts of the World Health Organization (WHO, metabolic syndrome (MS can be considered as pandemy of the XXI century, because its prevalence among the population of developed countries is about 25-35%. In this study with the purpose of complex investigation of the autonomic nervous system and endothelial function we included 66 patients with MS between the ages of 25 and 61 (46.9±9.9 years. A comparison group of apparently healthy individuals (16 individuals, average age of 45.3±2.3 years; P>0.05 was studied. To evaluate the response of microvascular tone, we used the method of wavelet analysis of skin temperature oscillations during cooling of the limb. All patients underwent the study of heart rate variability. The levels of insulin, endothelin-1, and vascular endothelial growth factor were determined using enzyme immunoassay. Patients with MS had significant differences in all metabolic parameters. Our study showed that in the group of MS there is a decrease of the variability of heart rhythm compared with the healthy group. Conducting cold test revealed signs of endothelial dysfunction in the MS group, which was manifested by the decrease of the index of vasodilation in the endothelial and neurogenic frequency range. In the study group we determined the increase in biochemical markers of endothelial dysfunction, which correlated with parameters of vasodilation. Also, the presence of endothelial dysfunction significantly correlated with signs of reduction of the variability of the heart rhythm.

  18. Heart rate variability reflects self-regulatory strength, effort, and fatigue.

    Science.gov (United States)

    Segerstrom, Suzanne C; Nes, Lise Solberg

    2007-03-01

    Experimental research reliably demonstrates that self-regulatory deficits are a consequence of prior self-regulatory effort. However, in naturalistic settings, although people know that they are sometimes vulnerable to saying, eating, or doing the wrong thing, they cannot accurately gauge their capacity to self-regulate at any given time. Because self-regulation and autonomic regulation colocalize in the brain, an autonomic measure, heart rate variability (HRV), could provide an index of self-regulatory strength and activity. During an experimental manipulation of self-regulation (eating carrots or cookies), HRV was elevated during high self-regulatory effort (eat carrots, resist cookies) compared with low self-regulatory effort (eat cookies, resist carrots). The experimental manipulation and higher HRV at baseline independently predicted persistence at a subsequent anagram task. HRV appears to index self-regulatory strength and effort, making it possible to study these phenomena in the field as well as the lab.

  19. Heart rate turbulence and variability in patients with ventricular arrhythmias

    Directory of Open Access Journals (Sweden)

    Diego Tarricone

    2009-08-01

    Full Text Available Background: To evaluate the changes in autonomic neural control mechanisms before malignant ventricular arrhythmias, we measured heart rate variability (HRV and heart rate turbulence (HRT in patients with ventricular tachycardia or fibrillation (Group I; n=6, non sustained ventricular tachycardia (Group II; n=32, frequent premature ventricular beats (Group III; n=26 and with ICD implantation (Group IV; n=11. Methods: Time domain parameters of HRV and turbulence onset (TO and slope (TS were calculated on 24 hour Holter recordings. Normal values were: SDNN > 70 msec for HRV, TO <0% and TS >2.5 msec/RR-I for HRT. Results: Whereas SDNN was within normal range and similar in all study groups, HRT parameters were significantly different in patients who experienced VT/VF during Holter recording. Abnormal TO and/or TS were present in 100% of Group I patients and only in about 50% of Group II and IV. On the contrary, normal HRT parameters were present in 40-70% of Group II, III and IV patients and none of Group I. Conclusions: These data suggest that HRT analysis is more suitable than HRV to detect those transient alterations in autonomic control mechanisms that are likely to play a major trigger role in the genesis of malignant cardiac arrhythmias. (Heart International 2007; 3: 51-7

  20. Compact variable rate laser for space application

    Data.gov (United States)

    National Aeronautics and Space Administration — We will focus on the development and test of high reliable, radiation tolerant, compact laser for planetary mission.  The laser will be able to operate at variable...

  1. Variability of sea ice deformation rates in the Arctic and their relationship with basin-scale wind forcing

    Directory of Open Access Journals (Sweden)

    A. Herman

    2012-12-01

    Full Text Available The temporal variability of the moments of probability distribution functions (pdfs of total sea ice deformation rates in the Arctic is analyzed in the context of the basin-scale wind forcing acting on the ice. The pdfs are estimated for 594 satellite-derived sea ice deformation maps from 11 winter seasons between 1996/1997 and 2007/2008, provided by the RADARSAT Geophysical Processor System. The temporal scale analyzed equals 3 days. The moments of the pdfs, calculated for a range of spatial scales (12.5–900 km, have two dominating components of variability: a seasonal cycle, with deformation rates decreasing throughout winter towards a minimum in March; and a short-term, synoptic variability, strongly correlated with the area-averaged magnitude of the wind stress over the Arctic, estimated based on the NCEP-DOE Reanalysis-2 data (correlation coefficient of 0.71 for the mean deformation rate. Due to scaling properties of the moments, logarithms of higher moments are strongly correlated with the wind stress as well. Exceptions are observed only at small spatial scales, as a result of extreme deformation events, not directly associated with large-scale wind forcing. By repeating the analysis within regions of different sizes and locations, we show that the wind–ice deformation correlation is largest at the basin scale and decreases with decreasing size of the area of study. Finally, we suggest that a positive trend in seasonally averaged correlation between sea ice deformation rates and the wind forcing, present in the analyzed data, may be related to an observed decrease in the multi-year ice area in the Arctic, indicating possibly even stronger correlations in the future.

  2. Heart rate variability analysis in sheep affected by transmissible spongiform encephalopathies

    Directory of Open Access Journals (Sweden)

    Konold Timm

    2011-12-01

    Full Text Available Abstract Background The function of the autonomic nervous system can be assessed by determining heart rate variability (HRV, which is impaired in some brainstem diseases in humans. Transmissible spongiform encephalopathies (TSEs in sheep are diseases characterised by accumulation of disease-associated prion protein in the brainstem, including nuclei of the parasympathetic nervous system. This study was undertaken to assess whether analysis of HRV can be used as an aid in the diagnosis of TSEs in clinically affected, naturally or experimentally infected sheep. Findings When HRV indices were compared between 41 clinical TSE cases (18 sheep infected with scrapie and 23 sheep infected with bovine spongiform encephalopathy, 11 control sheep and six sheep reported as scrapie suspects or dosed with BSE brain homogenate, which were not confirmed as TSE cases by postmortem tests, no significant differences were found between the groups. Median heart rate was significantly different but only when sheep were grouped by gender: it was higher in female TSE cases than in control sheep and higher in female than castrated male ovine classical BSE cases. Conclusions HRV analysis was not useful as a diagnostic aid for TSEs of sheep.

  3. Evoked response of heart rate variability using short-duration white noise.

    Science.gov (United States)

    Lee, Guo-She; Chen, Mei-Ling; Wang, Gin-You

    2010-06-24

    To investigate and to establish a model for evaluation of the instant cardiovascular responses to the noises of low-to-moderate intensity, sixteen healthy subjects were enrolled. The white noises were binaurally presented with a supra-aural earphone. The test intensities of noises were no noise, 50, 60, 70 and 80 dBA. Each noise was continued for 5 min and the electrocardiogram was simultaneously recorded. The cardiac autonomic responses were evaluated using power spectral analysis of the R-R contour obtained from digital signal processing of the ECG tracings. The result showed that the mean heart rate and mean blood pressure did not change significantly with the noises. However, the low-frequency power (LF) which represents cardiac autonomic modulations and the ratio (LHR) of LF to high-frequency power (HF) which reflects cardiac sympathetic modulations were significantly greater in the noise intensity of 50, 60, 70 and 80dBA (pnoise intensity (rho=0.90, pwhite noises can be detected using power spectral analysis of heart rate variability and the evoked responses may provide a sensitive way to evaluate the instant effect of noise to humans.

  4. Anxiety, attention, and decision making: The moderating role of heart rate variability.

    Science.gov (United States)

    Ramírez, Encarnación; Ortega, Ana Raquel; Reyes Del Paso, Gustavo A

    2015-12-01

    The current exploratory research examined whether high frequency heart rate variability (HF-HRV) modulates the association between anxiety and (1) executive attentional control during situations involving neutral stimuli, in which the distractor stimuli are in conflict with the target stimulus, and (2) risk aversion in decision making. Forty-five participants (21 with low and 24 with high trait-anxiety) performed a modified version of the Attention Network Test to measure attentional control, and the Balloon Analog Risk Task to measure risk aversion. HF-HRV was recorded during a rest period before completion of the tasks. Results showed that individuals with high anxiety and low HF-HRV have worse attentional control in the face of conflicting information as well as greater risk aversion, in comparison with individuals with both high anxiety and high HF-HRV or low anxiety (regardless of HF-HRV). HF-HRV was positively associated with attentional control and negatively associated with risk aversion. Furthermore, a strong negative association was observed between attentional control and risk aversion. These results suggest that HF-HRV modulates the influence of anxiety on both attentional control to neutral stimuli, and risk aversion in decision making. Greater HF-HRV appears to fulfill a protective role in highly anxious individuals. The associations observed also suggest that executive control of attention plays a relevant role in decision making. These results support the relevance of the autonomic nervous system in sustained cognition and are in accordance with theories in which vagal-mediated heart rate variability is taken as an indicator of prefrontal cortex inhibitory influences. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. An Attempt To Estimate The Contribution Of Variability Of Wetland Extent On The Variability Of The Atmospheric Methane Growth Rate In The Years 1993-2000.

    Science.gov (United States)

    Ringeval, B.; de Noblet-Ducoudre, N.; Prigent, C.; Bousquet, P.

    2006-12-01

    The atmospheric methane growth rate presents lots of seasonal and year-to-year variations. Large uncertainties still exist in the relative part of differents sources and sinks on these variations. We have considered, in this study, the main natural sources of methane and the supposed main variable source, i.e. wetlands, and tried to simulate the variations of their emissions considering the variability of the wetland extent and of the climate. For this study, we use the methane emission model of Walter et al. (2001) and the quantification of the flooded areas for the years 1993-2000 obtained with a suite of satellite observations by Prigent et al. (2001). The data necessary to the Walter's model are obtained with simulation of a dynamic global vegetation model ORCHIDEE (Krinner et al. (2005)) constrained by the NCC climate data (Ngo-Duc et al. (2005)) and after imposing a water-saturated soil to approach productivity of wetlands. We calculate global annual methane emissions from wetlands to be 400 Tg per year, that is higher than previous results obtained with fixed wetland extent. Simulations are realised to estimate the part of variability in the emissions explained by the variability of the wetland extent. It seems that the year-to-year emission variability is mainly explained by the interannual variability of wetland extent. The seasonnal variability is explained for 75% in the tropics and only for 40% in the north of 30°N by variability of wetlands extend. Finally, we compare results with a top-down approach of Bousquet et al.(2006).

  6. Phosphorus mobilization in rewetted peat and sand at variable flow rate and redox regimes

    DEFF Research Database (Denmark)

    Kjærgaard, Charlotte; Heiberg, Lisa; Jensen, Henning S.

    2012-01-01

    the upward percolation of groundwater with variable O2 content and flow rate, we investigated the hydro-biogeochemical Fe and P dynamics in intact cores of a carbon rich peat and carbon poor sand. Percolation of deionized water with high, low or no O2 supply at 10 °C caused markedly different in situ redox...... rates from 7.6 to 11 mg P m−2 day−1. Organic or particulate P contributed to 40–45% of total P losses from the peat. In contrast, the high O2 supply during high flow rate kept the peat oxic and lowered TP release rates to 6.7 mg P m−2 day−1. The carbon poor sand demonstrated that this soil type...... regimes in the two soils during 21 or 67 days of continuous percolation at either 1 or 4 mm h−1. Anoxic conditions occurred in the peat soil at both low oxygen supply and anoxic infiltration, causing reductive Fe(III) dissolution with high Fe(II) and P effluent concentrations and total P (TP) release...

  7. Fatigue shifts and scatters heart rate variability in elite endurance athletes.

    Directory of Open Access Journals (Sweden)

    Laurent Schmitt

    Full Text Available PURPOSE: This longitudinal study aimed at comparing heart rate variability (HRV in elite athletes identified either in 'fatigue' or in 'no-fatigue' state in 'real life' conditions. METHODS: 57 elite Nordic-skiers were surveyed over 4 years. R-R intervals were recorded supine (SU and standing (ST. A fatigue state was quoted with a validated questionnaire. A multilevel linear regression model was used to analyze relationships between heart rate (HR and HRV descriptors [total spectral power (TP, power in low (LF and high frequency (HF ranges expressed in ms(2 and normalized units (nu] and the status without and with fatigue. The variables not distributed normally were transformed by taking their common logarithm (log10. RESULTS: 172 trials were identified as in a 'fatigue' and 891 as in 'no-fatigue' state. All supine HR and HRV parameters (Beta±SE were significantly different (P<0.0001 between 'fatigue' and 'no-fatigue': HRSU (+6.27±0.61 bpm, logTPSU (-0.36±0.04, logLFSU (-0.27±0.04, logHFSU (-0.46±0.05, logLF/HFSU (+0.19±0.03, HFSU(nu (-9.55±1.33. Differences were also significant (P<0.0001 in standing: HRST (+8.83±0.89, logTPST (-0.28±0.03, logLFST (-0.29±0.03, logHFST (-0.32±0.04. Also, intra-individual variance of HRV parameters was larger (P<0.05 in the 'fatigue' state (logTPSU: 0.26 vs. 0.07, logLFSU: 0.28 vs. 0.11, logHFSU: 0.32 vs. 0.08, logTPST: 0.13 vs. 0.07, logLFST: 0.16 vs. 0.07, logHFST: 0.25 vs. 0.14. CONCLUSION: HRV was significantly lower in 'fatigue' vs. 'no-fatigue' but accompanied with larger intra-individual variance of HRV parameters in 'fatigue'. The broader intra-individual variance of HRV parameters might encompass different changes from no-fatigue state, possibly reflecting different fatigue-induced alterations of HRV pattern.

  8. smRithm: Graphical user interface for heart rate variability analysis.

    Science.gov (United States)

    Nara, Sanjeev; Kaur, Manvinder; Datta, Saurav

    2015-01-01

    Over the past 25 years, Heart rate variability (HRV) has become a non-invasive research and clinical tool for indirectly carrying out investigation of both cardiac and autonomic system function in both healthy and diseased. It provides valuable information about a wide range of cardiovascular disorders, pulmonary diseases, neurological diseases, etc. Its primary purpose is to access the functioning of the nervous system. The source of information for HRV analysis is the continuous beat to beat measurement of inter-beat intervals. The electrocardiography (ECG or EKG) is considered as the best way to measure inter-beat intervals. This paper proposes an open source Graphical User Interface (GUI): smRithm developed in MATLAB for HRV analysis that will apply effective techniques on the raw ECG signals to process and decompose it in a simpler manner to obtain more useful information out of signals that can be utilized for more powerful and efficient applications in the near future related to HRV.

  9. Prolonged non-metabolic heart rate variability reduction as a physiological marker of psychological stress in daily life

    NARCIS (Netherlands)

    Verkuil, B.; Brosschot, J.F.; Tollenaar, M.S.; Lane, R.D.; Thayer, J.F.

    2016-01-01

    BACKGROUND Prolonged cardiac activity that exceeds metabolic needs can be detrimental for somatic health. Psychological stress could result in such "additional cardiac activity." PURPOSE In this study, we examined whether prolonged additional reductions in heart rate variability (AddHRVr) can be

  10. Effects of omega-3 fatty acids on resting heart rate, heart rate recovery after exercise, and heart rate variability in men with healed myocardial infarctions and depressed ejection fractions.

    Science.gov (United States)

    O'Keefe, James H; Abuissa, Hussam; Sastre, Antonio; Steinhaus, David M; Harris, William S

    2006-04-15

    We explored possible mechanisms by which recommended intakes of omega-3 fatty acids may decrease the risk for sudden cardiac death in patients with documented coronary heart disease. The cardioprotective effects of omega-3 fatty acids have been documented in epidemiologic and randomized controlled trials. These fatty acids are presumed to decrease susceptibility to fatal arrhythmias, but whether this is mediated by classic risk factors or direct cardiac mechanisms is not known. Eighteen white men with a history of myocardial infarction and ejection fractions <40% were randomized to placebo or omega-3 fatty acids (585 mg of docosahexaenoic acid and 225 mg of eicosapentaenoic acid) for two 4-month periods in a crossover design. At the end of each period, heart rate (HR), HR variability, and rate of HR recovery after exercise were determined, as were effects on arterial compliance, blood pressure, cardiac function, and fasting serum levels of lipids and inflammatory markers. Omega-3 fatty acids decreased HR at rest from 73 +/- 13 to 68 +/- 13 beats/min (p <0.0001) and improved 1-minute HR recovery after exercise (-27 +/- 10 to -32 +/- 12 beats/min, p <0.01). HR variability in the high-frequency band increased (p <0.02), but no change was noted in overall HR variability. There were no significant effects on blood pressure, arterial compliance, lipids, or inflammatory markers. These changes are consistent with an increase in vagal activity and may in part explain the observed decrease in risk for sudden cardiac death seen with omega-3 fatty acid supplementation.

  11. Use of a prototype pulse oximeter for time series analysis of heart rate variability

    Science.gov (United States)

    González, Erika; López, Jehú; Hautefeuille, Mathieu; Velázquez, Víctor; Del Moral, Jésica

    2015-05-01

    This work presents the development of a low cost pulse oximeter prototype consisting of pulsed red and infrared commercial LEDs and a broad spectral photodetector used to register time series of heart rate and oxygen saturation of blood. This platform, besides providing these values, like any other pulse oximeter, processes the signals to compute a power spectrum analysis of the patient heart rate variability in real time and, additionally, the device allows access to all raw and analyzed data if databases construction is required or another kind of further analysis is desired. Since the prototype is capable of acquiring data for long periods of time, it is suitable for collecting data in real life activities, enabling the development of future wearable applications.

  12. Digital Heart-Rate Variability Parameter Monitoring and Assessment ASIC.

    Science.gov (United States)

    Massagram, W; Hafner, N; Mingqi Chen; Macchiarulo, L; Lubecke, V M; Boric-Lubecke, O

    2010-02-01

    This paper describes experimental results for an application-specific integrated circuit (ASIC), designed for digital heart rate variability (HRV) parameter monitoring and assessment. This ASIC chip measures beat-to-beat (RR) intervals and stores HRV parameters into its internal memory in real time. A wide range of short-term and long-term ECG signals obtained from Physionet was used for testing. The system detects R peaks with millisecond accuracy, and stores up to 2 min of continuous RR interval data and up to 4 min of RR interval histogram. The prototype chip was fabricated in a 0.5 ¿m complementary metal-oxide semiconductor technology on a 3×3 mm(2) die area, with a measured dynamic power consumption of 10 ¿W and measured leakage current of 2.62 nA. The HRV monitoring system including this HRV ASIC, an analog-to-digital converter, and a low complexity microcontroller was estimated to consume 32.5 ¿V, which is seven times lower power than a stand-alone microcontroller performing the same functions. Compact size, low cost, and low power consumption make this chip suitable for a miniaturized portable HRV monitoring system.

  13. Heart and soul: heart rate variability and major depression.

    Science.gov (United States)

    Kidwell, Meyrick; Ellenbroek, Bart A

    2018-04-01

    There is a bidirectional relationship between affective disorders and cardiovascular abnormalities, often described as a downward spiral, whereas major depressive disorders (MDD, and anxiety disorders) significantly increase the risk of developing cardiovascular diseases (CVD); CVD are also associated with increased risk of developing MDD (and anxiety disorders). Moreover, the prognosis and progression of CVD is significantly worsened in the presence of MDD. Heart rate variability (HRV) has often been suggested as a potential mediator in this comorbidity. In this review, we discuss HRV alterations in MDD. However, we mainly focus on the direct relationship between HRV alterations and psychiatric symptoms, rather than its relationship with CVD, as this has been reviewed elsewhere. After a general introduction to HRV and how it can be measured, we review how HRV is altered in MDD. We subsequently describe how antidepressant drugs affect HRV, showing that some classes (such as tricyclics) generally worsen HRV, whereas others (most notably selective serotonin reuptake inhibitors) have a more positive influence. We also review the effects of several other treatments, with a special focus on vagal nerve stimulation, finishing with some further considerations and recommendation for further research, both in humans and animals.

  14. Omega-3 Polyunsaturated Fatty Acids and Heart Rate Variability

    Directory of Open Access Journals (Sweden)

    Jeppe Hagstrup Christensen

    2011-11-01

    Full Text Available Omega-3 polyunsaturated fatty acids (PUFA may modulate autonomic control of the heart because omega-3 PUFA is abundant in the brain and other nervous tissue as well as in cardiac tissue. This might partly explain why omega-3 PUFA offer some protection against sudden cardiac death (SCD. The autonomic nervous system is involved in the pathogenesis of SCD. Heart rate variability (HRV can be used as a non-invasive marker of cardiac autonomic control and a low HRV is a predictor for SCD and arrhythmic events. Studies on HRV and omega-3 PUFA have been performed in several populations such as patients with ischemic heart disease, patients with diabetes mellitus, patients with chronic renal failure, and in healthy subjects as well as in children.. The studies have demonstrated a positive association between cellular content of omega-3 PUFA and HRV and supplementation with omega-3 PUFA seems to increase HRV which could be a possible explanation for decreased risk of arrhythmic events and SCD sometimes observed after omega-3 PUFA supplementation. However, the results are not consistent and further research is needed

  15. Sensitivity of adaptive enrichment trial designs to accrual rates, time to outcome measurement, and prognostic variables

    Directory of Open Access Journals (Sweden)

    Tianchen Qian

    2017-12-01

    Full Text Available Adaptive enrichment designs involve rules for restricting enrollment to a subset of the population during the course of an ongoing trial. This can be used to target those who benefit from the experimental treatment. Trial characteristics such as the accrual rate and the prognostic value of baseline variables are typically unknown when a trial is being planned; these values are typically assumed based on information available before the trial starts. Because of the added complexity in adaptive enrichment designs compared to standard designs, it may be of special concern how sensitive the trial performance is to deviations from assumptions. Through simulation studies, we evaluate the sensitivity of Type I error, power, expected sample size, and trial duration to different design characteristics. Our simulation distributions mimic features of data from the Alzheimer's Disease Neuroimaging Initiative cohort study, and involve two subpopulations based on a genetic marker. We investigate the impact of the following design characteristics: the accrual rate, the time from enrollment to measurement of a short-term outcome and the primary outcome, and the prognostic value of baseline variables and short-term outcomes. To leverage prognostic information in baseline variables and short-term outcomes, we use a semiparametric, locally efficient estimator, and investigate its strengths and limitations compared to standard estimators. We apply information-based monitoring, and evaluate how accurately information can be estimated in an ongoing trial.

  16. A Real-Time Analysis Method for Pulse Rate Variability Based on Improved Basic Scale Entropy

    Directory of Open Access Journals (Sweden)

    Yongxin Chou

    2017-01-01

    Full Text Available Base scale entropy analysis (BSEA is a nonlinear method to analyze heart rate variability (HRV signal. However, the time consumption of BSEA is too long, and it is unknown whether the BSEA is suitable for analyzing pulse rate variability (PRV signal. Therefore, we proposed a method named sliding window iterative base scale entropy analysis (SWIBSEA by combining BSEA and sliding window iterative theory. The blood pressure signals of healthy young and old subjects are chosen from the authoritative international database MIT/PhysioNet/Fantasia to generate PRV signals as the experimental data. Then, the BSEA and the SWIBSEA are used to analyze the experimental data; the results show that the SWIBSEA reduces the time consumption and the buffer cache space while it gets the same entropy as BSEA. Meanwhile, the changes of base scale entropy (BSE for healthy young and old subjects are the same as that of HRV signal. Therefore, the SWIBSEA can be used for deriving some information from long-term and short-term PRV signals in real time, which has the potential for dynamic PRV signal analysis in some portable and wearable medical devices.

  17. State Anxiety and Nonlinear Dynamics of Heart Rate Variability in Students.

    Science.gov (United States)

    Dimitriev, Dimitriy A; Saperova, Elena V; Dimitriev, Aleksey D

    2016-01-01

    Clinical and experimental research studies have demonstrated that the emotional experience of anxiety impairs heart rate variability (HRV) in humans. The present study investigated whether changes in state anxiety (SA) can also modulate nonlinear dynamics of heart rate. A group of 96 students volunteered to participate in the study. For each student, two 5-minute recordings of beat intervals (RR) were performed: one during a rest period and one just before a university examination, which was assumed to be a real-life stressor. Nonlinear analysis of HRV was performed. The Spielberger's State-Trait Anxiety Inventory was used to assess the level of SA. Before adjusting for heart rate, a Wilcoxon matched pairs test showed significant decreases in Poincaré plot measures, entropy, largest Lyapunov exponent (LLE), and pointwise correlation dimension (PD2), and an increase in the short-term fractal-like scaling exponent of detrended fluctuation analysis (α1) during the exam session, compared with the rest period. A Pearson analysis indicated significant negative correlations between the dynamics of SA and Poincaré plot axes ratio (SD1/SD2), and between changes in SA and changes in entropy measures. A strong negative correlation was found between the dynamics of SA and LLE. A significant positive correlation was found between the dynamics of SA and α1. The decreases in Poincaré plot measures (SD1, complex correlation measure), entropy measures, and LLE were still significant after adjusting for heart rate. Corrected α1 was increased during the exam session. As before, the dynamics of adjusted LLE was significantly correlated with the dynamics of SA. The qualitative increase in SA during academic examination was related to the decrease in the complexity and size of the Poincaré plot through a reduction of both the interbeat interval and its variation.

  18. State Anxiety and Nonlinear Dynamics of Heart Rate Variability in Students.

    Directory of Open Access Journals (Sweden)

    Dimitriy A Dimitriev

    Full Text Available Clinical and experimental research studies have demonstrated that the emotional experience of anxiety impairs heart rate variability (HRV in humans. The present study investigated whether changes in state anxiety (SA can also modulate nonlinear dynamics of heart rate.A group of 96 students volunteered to participate in the study. For each student, two 5-minute recordings of beat intervals (RR were performed: one during a rest period and one just before a university examination, which was assumed to be a real-life stressor. Nonlinear analysis of HRV was performed. The Spielberger's State-Trait Anxiety Inventory was used to assess the level of SA.Before adjusting for heart rate, a Wilcoxon matched pairs test showed significant decreases in Poincaré plot measures, entropy, largest Lyapunov exponent (LLE, and pointwise correlation dimension (PD2, and an increase in the short-term fractal-like scaling exponent of detrended fluctuation analysis (α1 during the exam session, compared with the rest period. A Pearson analysis indicated significant negative correlations between the dynamics of SA and Poincaré plot axes ratio (SD1/SD2, and between changes in SA and changes in entropy measures. A strong negative correlation was found between the dynamics of SA and LLE. A significant positive correlation was found between the dynamics of SA and α1. The decreases in Poincaré plot measures (SD1, complex correlation measure, entropy measures, and LLE were still significant after adjusting for heart rate. Corrected α1 was increased during the exam session. As before, the dynamics of adjusted LLE was significantly correlated with the dynamics of SA.The qualitative increase in SA during academic examination was related to the decrease in the complexity and size of the Poincaré plot through a reduction of both the interbeat interval and its variation.

  19. Real-time Continuous Assessment Method for Mental and Physiological Condition using Heart Rate Variability

    Science.gov (United States)

    Yoshida, Yutaka; Yokoyama, Kiyoko; Ishii, Naohiro

    It is necessary to monitor the daily health condition for preventing stress syndrome. In this study, it was proposed the method assessing the mental and physiological condition, such as the work stress or the relaxation, using heart rate variability at real time and continuously. The instantanuous heart rate (HR), and the ratio of the number of extreme points (NEP) and the number of heart beats were calculated for assessing mental and physiological condition. In this method, 20 beats heart rate were used to calculate these indexes. These were calculated in one beat interval. Three conditions, which are sitting rest, performing mental arithmetic and watching relaxation movie, were assessed using our proposed algorithm. The assessment accuracies were 71.9% and 55.8%, when performing mental arithmetic and watching relaxation movie respectively. In this method, the mental and physiological condition was assessed using only 20 regressive heart beats, so this method is considered as the real time assessment method.

  20. On diffusion processes with variable drift rates as models for decision making during learning

    International Nuclear Information System (INIS)

    Eckhoff, P; Holmes, P; Law, C; Connolly, P M; Gold, J I

    2008-01-01

    We investigate Ornstein-Uhlenbeck and diffusion processes with variable drift rates as models of evidence accumulation in a visual discrimination task. We derive power-law and exponential drift-rate models and characterize how parameters of these models affect the psychometric function describing performance accuracy as a function of stimulus strength and viewing time. We fit the models to psychophysical data from monkeys learning the task to identify parameters that best capture performance as it improves with training. The most informative parameter was the overall drift rate describing the signal-to-noise ratio of the sensory evidence used to form the decision, which increased steadily with training. In contrast, secondary parameters describing the time course of the drift during motion viewing did not exhibit steady trends. The results indicate that relatively simple versions of the diffusion model can fit behavior over the course of training, thereby giving a quantitative account of learning effects on the underlying decision process

  1. Geomagnetic storm under laboratory conditions: randomized experiment

    Science.gov (United States)

    Gurfinkel, Yu I.; Vasin, A. L.; Pishchalnikov, R. Yu; Sarimov, R. M.; Sasonko, M. L.; Matveeva, T. A.

    2017-10-01

    The influence of the previously recorded geomagnetic storm (GS) on human cardiovascular system and microcirculation has been studied under laboratory conditions. Healthy volunteers in lying position were exposed under two artificially created conditions: quiet (Q) and storm (S). The Q regime playbacks a noise-free magnetic field (MF) which is closed to the natural geomagnetic conditions on Moscow's latitude. The S regime playbacks the initially recorded 6-h geomagnetic storm which is repeated four times sequentially. The cardiovascular response to the GS impact was assessed by measuring capillary blood velocity (CBV) and blood pressure (BP) and by the analysis of the 24-h ECG recording. A storm-to-quiet ratio for the cardio intervals (CI) and the heart rate variability (HRV) was introduced in order to reveal the average over group significant differences of HRV. An individual sensitivity to the GS was estimated using the autocorrelation function analysis of the high-frequency (HF) part of the CI spectrum. The autocorrelation analysis allowed for detection a group of subjects of study which autocorrelation functions (ACF) react differently in the Q and S regimes of exposure.

  2. A Series of Case Studies of Tinnitus Suppression With Mixed Background Stimuli in a Cochlear Implant

    Science.gov (United States)

    Keiner, A. J.; Walker, Kurt; Deshpande, Aniruddha K.; Witt, Shelley; Killian, Matthijs; Ji, Helena; Patrick, Jim; Dillier, Norbert; van Dijk, Pim; Lai, Wai Kong; Hansen, Marlan R.; Gantz, Bruce

    2015-01-01

    Purpose Background sounds provided by a wearable sound playback device were mixed with the acoustical input picked up by a cochlear implant speech processor in an attempt to suppress tinnitus. Method First, patients were allowed to listen to several sounds and to select up to 4 sounds that they thought might be effective. These stimuli were programmed to loop continuously in the wearable playback device. Second, subjects were instructed to use 1 background sound each day on the wearable device, and they sequenced the selected background sounds during a 28-day trial. Patients were instructed to go to a website at the end of each day and rate the loudness and annoyance of the tinnitus as well as the acceptability of the background sound. Patients completed the Tinnitus Primary Function Questionnaire (Tyler, Stocking, Secor, & Slattery, 2014) at the beginning of the trial. Results Results indicated that background sounds were very effective at suppressing tinnitus. There was considerable variability in sounds preferred by the subjects. Conclusion The study shows that a background sound mixed with the microphone input can be effective for suppressing tinnitus during daily use of the sound processor in selected cochlear implant users. PMID:26001407

  3. Geomagnetic storm under laboratory conditions: randomized experiment.

    Science.gov (United States)

    Gurfinkel, Yu I; Vasin, A L; Pishchalnikov, R Yu; Sarimov, R M; Sasonko, M L; Matveeva, T A

    2018-04-01

    The influence of the previously recorded geomagnetic storm (GS) on human cardiovascular system and microcirculation has been studied under laboratory conditions. Healthy volunteers in lying position were exposed under two artificially created conditions: quiet (Q) and storm (S). The Q regime playbacks a noise-free magnetic field (MF) which is closed to the natural geomagnetic conditions on Moscow's latitude. The S regime playbacks the initially recorded 6-h geomagnetic storm which is repeated four times sequentially. The cardiovascular response to the GS impact was assessed by measuring capillary blood velocity (CBV) and blood pressure (BP) and by the analysis of the 24-h ECG recording. A storm-to-quiet ratio for the cardio intervals (CI) and the heart rate variability (HRV) was introduced in order to reveal the average over group significant differences of HRV. An individual sensitivity to the GS was estimated using the autocorrelation function analysis of the high-frequency (HF) part of the CI spectrum. The autocorrelation analysis allowed for detection a group of subjects of study which autocorrelation functions (ACF) react differently in the Q and S regimes of exposure.

  4. FODA/IBEA satellite access scheme for MIXED traffic at variable bit and coding rates system description

    OpenAIRE

    Celandroni, Nedo; Ferro, Erina; Mihal, Vlado; Potort?, Francesco

    1992-01-01

    This report describes the FODA system working at variable coding and bit rates (FODA/IBEA-TDMA) FODA/IBEA is the natural evolution of the FODA-TDMA satellite access scheme working at 2 Mbit/s fixed rate with data 1/2 coded or uncoded. FODA-TDMA was used in the European SATINE-II experiment [8]. We remind here that the term FODA/IBEA system is comprehensive of the FODA/IBEA-TDMA (1) satellite access scheme and of the hardware prototype realised by the Marconi R.C. (U.K.). Both of them come fro...

  5. Analysis of variables affecting unemployment rate and detecting for cluster in West Java, Central Java, and East Java in 2012

    Science.gov (United States)

    Samuel, Putra A.; Widyaningsih, Yekti; Lestari, Dian

    2016-02-01

    The objective of this study is modeling the Unemployment Rate (UR) in West Java, Central Java, and East Java, with rate of disease, infant mortality rate, educational level, population size, proportion of married people, and GDRP as the explanatory variables. Spatial factors are also considered in the modeling since the closer the distance, the higher the correlation. This study uses the secondary data from BPS (Badan Pusat Statistik). The data will be analyzed using Moran I test, to obtain the information about spatial dependence, and using Spatial Autoregressive modeling to obtain the information, which variables are significant affecting UR and how great the influence of the spatial factors. The result is, variables proportion of married people, rate of disease, and population size are related significantly to UR. In all three regions, the Hotspot of unemployed will also be detected districts/cities using Spatial Scan Statistics Method. The results are 22 districts/cities as a regional group with the highest unemployed (Most likely cluster) in the study area; 2 districts/cities as a regional group with the highest unemployed in West Java; 1 district/city as a regional groups with the highest unemployed in Central Java; 15 districts/cities as a regional group with the highest unemployed in East Java.

  6. Cross-Layer Design of Source Rate Control and Congestion Control for Wireless Video Streaming

    Directory of Open Access Journals (Sweden)

    Peng Zhu

    2007-01-01

    Full Text Available Cross-layer design has been used in streaming video over the wireless channels to optimize the overall system performance. In this paper, we extend our previous work on joint design of source rate control and congestion control for video streaming over the wired channel, and propose a cross-layer design approach for wireless video streaming. First, we extend the QoS-aware congestion control mechanism (TFRCC proposed in our previous work to the wireless scenario, and provide a detailed discussion about how to enhance the overall performance in terms of rate smoothness and responsiveness of the transport protocol. Then, we extend our previous joint design work to the wireless scenario, and a thorough performance evaluation is conducted to investigate its performance. Simulation results show that by cross-layer design of source rate control at application layer and congestion control at transport layer, and by taking advantage of the MAC layer information, our approach can avoid the throughput degradation caused by wireless link error, and better support the QoS requirements of the application. Thus, the playback quality is significantly improved, while good performance of the transport protocol is still preserved.

  7. Effects of autogenic training on stress response and heart rate variability in nursing students.

    Science.gov (United States)

    Lim, Seung-Joo; Kim, Chunmi

    2014-12-01

    This study was undertaken to confirm the effects of autogenic training (AT) on stress response and heart rate variability in nursing school students experiencing stress related to clinical training. The study was carried out from September 2012 to April 2013 in a quasi-experimental nonequivalent control group using a pretest-posttest design. The participants were 40 nursing students in their third year at either of two nursing colleges. All consented to participate. Nineteen nursing students at one college were assigned to the experimental group and underwent the 8-week AT program, and the other 21 were assigned to the control group and did not undergo any training. Stress response was assessed by questionnaire and HRV was measured three times, that is, before the program, at the end of the program, and 6 months after the end of the AT program. A significant time/group interaction was found for stress response (F = 4.68, p = .012), a subjective indicator. However, no significant interaction was found for the objective indicators of heart rate variability, normalized low frequency (F = 2.59, p = .090), normalized high frequency (F = 2.59, p = .090), or low frequency to high frequency ratio (F = 1.38, p = .257). The results suggest that AT provides an acceptable approach to stress reduction in nursing students. Copyright © 2014. Published by Elsevier B.V.

  8. The forgotten role of central volume in low frequency oscillations of heart rate variability.

    Directory of Open Access Journals (Sweden)

    Manuela Ferrario

    Full Text Available The hypothesis that central volume plays a key role in the source of low frequency (LF oscillations of heart rate variability (HRV was tested in a population of end stage renal disease patients undergoing conventional hemodialysis (HD treatment, and thus subject to large fluid shifts and sympathetic activation. Fluid overload (FO in 58 chronic HD patients was assessed by whole body bioimpedance measurements before the midweek HD session. Heart Rate Variability (HRV was measured using 24-hour Holter electrocardiogram recordings starting before the same HD treatment. Time domain and frequency domain analyses were performed on HRV signals. Patients were retrospectively classified in three groups according to tertiles of FO normalized to the extracellular water (FO/ECW%. These groups were also compared after stratification by diabetes mellitus. Patients with the low to medium hydration status before the treatment (i.e. 1st and 2nd FO/ECW% tertiles showed a significant increase in LF power during last 30 min of HD compared to dialysis begin, while no significant change in LF power was seen in the third group (i.e. those with high pre-treatment hydration values. In conclusion, several mechanisms can generate LF oscillations in the cardiovascular system, including baroreflex feedback loops and central oscillators. However, the current results emphasize the role played by the central volume in determining the power of LF oscillations.

  9. The forgotten role of central volume in low frequency oscillations of heart rate variability.

    Science.gov (United States)

    Ferrario, Manuela; Moissl, Ulrich; Garzotto, Francesco; Cruz, Dinna N; Tetta, Ciro; Signorini, Maria G; Ronco, Claudio; Grassmann, Aileen; Cerutti, Sergio; Guzzetti, Stefano

    2015-01-01

    The hypothesis that central volume plays a key role in the source of low frequency (LF) oscillations of heart rate variability (HRV) was tested in a population of end stage renal disease patients undergoing conventional hemodialysis (HD) treatment, and thus subject to large fluid shifts and sympathetic activation. Fluid overload (FO) in 58 chronic HD patients was assessed by whole body bioimpedance measurements before the midweek HD session. Heart Rate Variability (HRV) was measured using 24-hour Holter electrocardiogram recordings starting before the same HD treatment. Time domain and frequency domain analyses were performed on HRV signals. Patients were retrospectively classified in three groups according to tertiles of FO normalized to the extracellular water (FO/ECW%). These groups were also compared after stratification by diabetes mellitus. Patients with the low to medium hydration status before the treatment (i.e. 1st and 2nd FO/ECW% tertiles) showed a significant increase in LF power during last 30 min of HD compared to dialysis begin, while no significant change in LF power was seen in the third group (i.e. those with high pre-treatment hydration values). In conclusion, several mechanisms can generate LF oscillations in the cardiovascular system, including baroreflex feedback loops and central oscillators. However, the current results emphasize the role played by the central volume in determining the power of LF oscillations.

  10. Biofeedback on heart rate variability in cardiac rehabilitation: practical feasibility and psycho-physiological effects.

    Science.gov (United States)

    Climov, Daniela; Lysy, Camille; Berteau, Sylvain; Dutrannois, Jacques; Dereppe, Hubert; Brohet, Christian; Melin, Jacques

    2014-06-01

    Biofeedback is a self-regulation therapy by which the patient learns how to optimize the functioning of his autonomic nervous system. It has been applied to patients with various cardiovascular disorders. The purpose of this study was to investigate the practical feasibility and the psychophysiological effects of biofeedback applied to heart rate variability (HRV biofeedback) in order to increase cardiac coherence in coronary artery disease (CAD) patients participating in a cardiac rehabilitation programme. In this randomised and controlled study, 31 CAD patients were randomly assigned to an experimental or to a control group. The experimental group participated in a programme of 10 sessions of cardiac coherence biofeedback training, in addition to the rehabilitation programme. The control group participated in the usual cardiac rehabilitation programme only. Physiological variables (systolic and diastolic blood pressure, SDNN) and psychosocial variables (anxiety, depression, type D personality) were measured at the start and at the end of the programme in both groups. Statistical comparisons assessed the inter and intra group differences. The small sample size precludes any firm conclusions concerning the effect of cardiac coherence biofeedback on physiological or psychological variables. However, we observed a significant increase of the percentage of cardiac coherence, in relation with an increased SDNN index. Our study demonstrated the practical feasibility of cardiac coherence biofeedback training in CAD patients. Further research is desirable to investigate the potential benefit of cardiac coherence biofeedback as an adjunct to stress management in cardiac rehabilitation.

  11. Visibility graph analysis of very short-term heart rate variability during sleep

    Science.gov (United States)

    Hou, F. Z.; Li, F. W.; Wang, J.; Yan, F. R.

    2016-09-01

    Based on a visibility-graph algorithm, complex networks were constructed from very short-term heart rate variability (HRV) during different sleep stages. Network measurements progressively changed from rapid eye movement (REM) sleep to light sleep and then deep sleep, exhibiting promising ability for sleep assessment. Abnormal activation of the cardiovascular controls with enhanced 'small-world' couplings and altered fractal organization during REM sleep indicates that REM could be a potential risk factor for adverse cardiovascular event, especially in males, older individuals, and people who are overweight. Additionally, an apparent influence of gender, aging, and obesity on sleep was demonstrated in healthy adults, which may be helpful for establishing expected sleep-HRV patterns in different populations.

  12. Detailed heart rate variability analysis in athletes.

    Science.gov (United States)

    Kiss, Orsolya; Sydó, Nóra; Vargha, Péter; Vágó, Hajnalka; Czimbalmos, Csilla; Édes, Eszter; Zima, Endre; Apponyi, Györgyi; Merkely, Gergő; Sydó, Tibor; Becker, Dávid; Allison, Thomas G; Merkely, Béla

    2016-08-01

    Heart rate variability (HRV) analysis has been used to evaluate patients with various cardiovascular diseases. While the vast majority of HRV studies have focused on pathological states, our study focuses on the less explored area of HRV analysis across different training intensity and sports. We aimed to measure HRV in healthy elite and masters athletes and compare to healthy, but non-athletic controls. Time-domain HRV analysis was applied in 138 athletes (male 110, age 28.4 ± 8.3) and 100 controls (male 56, age 28.3 ± 6.9) during Holter monitoring (21.3 ± 3.0 h). All studied parameters were higher in elite athletes compared to controls [SDNN (CI) 225.3 (216.2-234.5) vs 158.6 (150.2-167.1) ms; SDNN Index (CI) 99.6 (95.6-103.7) vs 72.4 (68.7-76.2) ms; pNN50 (CI) 24.2 (22.2-26.3) vs 14.4 (12.7-16.3) %; RMSSD (CI) 71.8 (67.6-76.2) vs 50.8 (46.9-54.8) ms; p HRV values than controls, but no significant differences were found between elite athletes and masters athletes. Some parameters were higher in canoeists-kayakers and bicyclists than runners. Lower cut-off values in elite athletes were SDNN: 147.4 ms, SDNN Index: 66.6 ms, pNN50: 9.7 %, RMSSD: 37.9 ms. Autonomic regulation in elite athletes described with HRV is significantly different than in healthy controls. Sports modality and level of performance, but not age- or sex-influenced HRV. Our study provides athletic normal HRV values. Further investigations are needed to determine its role in risk stratification, optimization of training, or identifying overtraining.

  13. Heart rate variability in workers chronically exposed to lead.

    Science.gov (United States)

    Gajek, Jacek; Zyśko, Dorota; Chlebda, Ewa

    2004-07-01

    Lead is a strong neurotoxin. The effects of lead on the activity of the autonomic nervous system, assessed by the use of heart rate variability (HRV) analysis, have not yet been established. To assess the effects of occupational chronic lead exposure on the autonomic nervous system activity. The study group consisted of 22 copper foundry workers (mean age 41.8+/-8.7 years) who had elevated parameters of lead overload and were admitted to the hospital for chelate therapy. The control group consisted of 13 age-matched healthy males. Lead concentration was measured with the use of atomic absorption spectrophotometry, and concentration of free protoporphyrins in erythrocytes (FEP) using a fluorometric method. Each patient underwent 24-hour ambulatory ECG monitoring, and standard short-term as well as long-term HRV parameters were obtained. There were no significant differences between patients and controls in HRV parameters. In the control group, HRV parameters correlated with age. In patients, a significant negative correlation between lead concentration and some short-term HRV parameters calculated during the night was found: SDNN (r=-0.48, p<0.05), TP (r=-0.48, p<0.01) and LF (r=-0.48, p<0.01). In patients, a negative correlation between lead concentration and HFnight/HFday index was found (r=-0.47 p<0.01), whereas in controls this correlation was positive (r=0.66 p<0.05). Overall HRV indices are similar in subjects exposed to lead and in healthy controls. A decrease in the physiological elevation of HF values during the night, together with an increase in lead blood concentration and lack of relationship between age and HRV parameters in workers chronically exposed to lead may suggest disturbances of the autonomic system. In subjects not exposed to lead a decrease in heart rate with an increase in FEP concentration was observed.

  14. Statistical variability and confidence intervals for planar dose QA pass rates

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Daniel W.; Nelms, Benjamin E.; Attwood, Kristopher; Kumaraswamy, Lalith; Podgorsak, Matthew B. [Department of Physics, State University of New York at Buffalo, Buffalo, New York 14260 (United States) and Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States); Department of Biostatistics, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Molecular and Cellular Biophysics and Biochemistry, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States) and Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14214 (United States)

    2011-11-15

    Purpose: The most common metric for comparing measured to calculated dose, such as for pretreatment quality assurance of intensity-modulated photon fields, is a pass rate (%) generated using percent difference (%Diff), distance-to-agreement (DTA), or some combination of the two (e.g., gamma evaluation). For many dosimeters, the grid of analyzed points corresponds to an array with a low areal density of point detectors. In these cases, the pass rates for any given comparison criteria are not absolute but exhibit statistical variability that is a function, in part, on the detector sampling geometry. In this work, the authors analyze the statistics of various methods commonly used to calculate pass rates and propose methods for establishing confidence intervals for pass rates obtained with low-density arrays. Methods: Dose planes were acquired for 25 prostate and 79 head and neck intensity-modulated fields via diode array and electronic portal imaging device (EPID), and matching calculated dose planes were created via a commercial treatment planning system. Pass rates for each dose plane pair (both centered to the beam central axis) were calculated with several common comparison methods: %Diff/DTA composite analysis and gamma evaluation, using absolute dose comparison with both local and global normalization. Specialized software was designed to selectively sample the measured EPID response (very high data density) down to discrete points to simulate low-density measurements. The software was used to realign the simulated detector grid at many simulated positions with respect to the beam central axis, thereby altering the low-density sampled grid. Simulations were repeated with 100 positional iterations using a 1 detector/cm{sup 2} uniform grid, a 2 detector/cm{sup 2} uniform grid, and similar random detector grids. For each simulation, %/DTA composite pass rates were calculated with various %Diff/DTA criteria and for both local and global %Diff normalization

  15. Heart rate variability to monitor performance in elite athletes: Criticalities and avoidable pitfalls.

    Science.gov (United States)

    Lucini, Daniela; Marchetti, Ilaria; Spataro, Antonio; Malacarne, Mara; Benzi, Manuela; Tamorri, Stefano; Sala, Roberto; Pagani, Massimo

    2017-08-01

    Spectral analysis of Heart Rate Variability (HRV) is a simple, non-invasive technique that is widely used in sport to assess sympatho-vagal regulation of the heart. Its employment is increasing partly due to the rising usage of wearable devices. However data acquisition using these devices may be suboptimal because they cannot discriminate between sinus and non-sinus beats and do not record any data regarding respiratory frequency. This information is mandatory for a correct clinical interpretation. This study involved 974 elite athletes, all of them underwent a complete autonomic assessment, by way of Autoregressive HRV analysis. In 91 subjects (9% of the total population) we observed criticalities of either cardiac rhythm or respiration. Through perusal of one-lead ECG analysis we observed that 77 subjects had atrial or ventricular ectopy, i.e. conditions which impair stationarity and sinus rhythm. Running anyway autonomic nervous system analysis in this population, we observed that RR variance and raw values of LF and HF regions are significantly higher in arrhythmic subjects. In addition 14 subjects had slow (about 6 breath/min, 0.1Hz) respiration. This condition clouds the separation between LF from HF spectral regions of RR interval variability, respectively markers of the prevalent sympathetic and vagal modulation of SA node and of their synergistic interaction. Caution must be payed when assessing HRV with non-ECG wearable devices. Recording ECG signal and ensuring that respiratory rate is higher than 10 breath/min are both prerequisites for a more reliable analysis of HRV particularly in athletes. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Longitudinal Associations of Leptin and Adiponectin with Heart Rate Variability in Children

    Directory of Open Access Journals (Sweden)

    Roos Van De Wielle

    2017-07-01

    Full Text Available For early prevention of cardiovascular disease, early detection and risk factor insights are necessary. The autonomic balance reflects cardiovascular risk and can be measured by heart rate variability (HRV. Therefore, our purpose is to examine associations between HRV and the energy-related biomarkers leptin and adiponectin in children. Participants of this study were Belgian children recruited for the longitudinal ChiBS study (year 2010–2012. HRV was measured and fasting blood samples were taken in 249 children at baseline (4.4–11.0 y and 223 children at follow-up (6.7–12.2 y. Cross-sectional and longitudinal linear regression analyses were separated by sex and adjusted for age, socio-economic status, body fat%, negative emotions, puberty, and mean heart rate. Leptin was a negative cross-sectional and longitudinal predictor of parasympathetic activity in boys; while leptin in girls was cross-sectionally associated with higher LF and LF/HF suggesting sympathetic predominance. Adiponectin was a negative cross-sectional and longitudinal predictor of parasympathetic activity in boys; but when adjusting for mean heart rate, this effect disappeared and adiponectin was a positive cross-sectional and longitudinal predictor of parasympathetic activity in girls. These results stress the importance of considering sex differences and adjustment for heart rate in testing HRV predictors. Leptin seemed disadvantageous for the autonomic balance, while adiponectin seemed advantageous for the autonomic balance in girls only. More research is needed to see whether leptin and adiponectin are interesting in cardiovascular screening/prevention or in determining the cardiovascular gain during weight loss follow-up.

  17. Heart rate variability in type 2 diabetes mellitus.

    Science.gov (United States)

    Stuckey, Melanie I; Petrella, Robert J

    2013-01-01

    Heart rate variability (HRV) is a noninvasive measure of cardiac autonomic modulation. Time and frequency domain measures have primarily been examined in patients with type 2 diabetes mellitus (T2D). Not only do frequency domain HRV parameters tend to be reduced in T2D, but healthy individuals with low HRV are also more likely to develop T2D. Furthermore, patients with T2D with low HRV have an increased prevalence of complications and risk of mortality compared with those with normal autonomic function. These findings provide support for the use of HRV as a risk indicator in T2D. Exercise is considered an important component to T2D prevention and treatment strategies. To date, few studies have examined the changes in HRV with exercise in T2D. One study showed changes in resting HRV, two studies showed changes in HRV during or following acute stressors, and one study showed no changes in HRV but improvements in baroreflex sensitivity. The most pronounced changes in HRV were realized following the exercise intervention with the greatest frequency of supervised exercise sessions and with the greatest intensity and duration of exercise bouts. These findings suggest that exercise following current American College of Sports Medicine/American Diabetes Association guidelines may be important in the prevention and treatment of T2D to improve autonomic function and reduce the risk of complications and mortality.

  18. Heart rate variability interventions for concussion and rehabilitation.

    Science.gov (United States)

    Conder, Robert L; Conder, Alanna A

    2014-01-01

    The study of heart rate variability (HRV) has emerged as an essential component of cardiovascular health, as well as a physiological mechanism by which one can increase the interactive communication between the cardiac and the neurocognitive systems (i.e., the body and the brain). It is well-established that lack of HRV implies cardiopathology, morbidity, reduced quality-of-life, and precipitous mortality. On the positive, optimal HRV has been associated with good cardiovascular health, autonomic nervous system (ANS) control, emotional regulation, and enhanced neurocognitive processing. In addition to health benefits, optimal HRV has been shown to improve neurocognitive performance by enhancing focus, visual acuity and readiness, and by promoting emotional regulation needed for peak performance. In concussed athletes and soldiers, concussions not only alter brain connectivity, but also alter cardiac functioning and impair cardiovascular performance upon exertion. Altered sympathetic and parasympathetic balance in the ANS has been postulated as a critical factor in refractory post concussive syndrome (PCS). This article will review both the pathological aspects of reduced HRV on athletic performance, as well as the cardiovascular and cerebrovascular components of concussion and PCS. Additionally, this article will review interventions with HRV biofeedback (HRV BFB) training as a promising and underutilized treatment for sports and military-related concussion. Finally, this article will review research and promising case studies pertaining to use of HRV BFB for enhancement of cognition and performance, with applicability to concussion rehabilitation.

  19. Influence of forced respiration on nonlinear dynamics in heart rate variability

    DEFF Research Database (Denmark)

    Kanters, J K; Højgaard, M V; Agner, E

    1997-01-01

    Although it is doubtful whether the normal sinus rhythm can be described as low-dimensional chaos, there is evidence for inherent nonlinear dynamics and determinism in time series of consecutive R-R intervals. However, the physiological origin for these nonlinearities is unknown. The aim...... with a metronome set to 12 min(-1). Nonlinear dynamics were measured as the correlation dimension and the nonlinear prediction error. Complexity expressed as correlation dimension was unchanged from normal respiration, 9.1 +/- 0.5, compared with forced respiration, 9.3 +/- 0.6. Also, nonlinear determinism...... expressed as the nonlinear prediction error did not differ between spontaneous respiration, 32.3 +/- 3.4 ms, and forced respiration, 31.9 +/- 5.7. It is concluded that the origin of the nonlinear dynamics in heart rate variability is not a nonlinear input from the respiration into the cardiovascular...

  20. High-Intensity Interval Exercises' Acute Impact on Heart Rate Variability: Comparison Between Whole-Body and Cycle Ergometer Protocols.

    Science.gov (United States)

    Schaun, Gustavo Z; Del Vecchio, Fabrício B

    2018-01-01

    Schaun, GZ and Del Vecchio, FB. High-intensity interval exercises' acute impact on heart rate variability: comparison between whole-body and cycle ergometer protocols. J Strength Cond Res 32(1): 223-229, 2018-Study aimed to compare the effects of 2 high-intensity interval training (HIIT) protocols on heart rate variability. Twelve young adult males (23.3 ± 3.9 years, 177.8 ± 7.4 cm, 76.9 ± 12.9 kg) volunteered to participate. In a randomized cross-over design, subjects performed 2 HIIT protocols, 1 on a cycle ergometer (Tabata protocol [TBT]; eight 20-second bouts at 170% Pmax interspersed by 10-second rest) and another with whole-body calisthenic exercises (McRae protocol; eight 20-second all-out intervals interspersed by 10-second rest). Heart rate variability outcomes in the time, frequency, and nonlinear domains were assessed on 3 moments: (a) presession; (b) immediately postsession; and (c) 24 hours postsession. Results revealed that RRmean, Ln rMSSD, Ln high frequency (HF), and Ln low frequency (LF) were significantly reduced immediately postsession (p ≤ 0.001) and returned to baseline 24 h after both protocols. In addition, LF/HF ratio was reduced 24 h postsession (p ≤ 0.01) and SD2 was significantly lower immediately postsession only in TBT. Our main finding was that responses from heart rate autonomic control were similar in both protocols, despite different modes of exercise performed. Specifically, exercises resulted in a high parasympathetic inhibition immediately after session with subsequent recovery within 1 day. These results suggest that subjects were already recovered the day after and can help coaches to better program training sessions with such protocols.

  1. An Analysis of Programmatic Variables Relating to the Pass Rates on the Licensure Examination by Practical Nurses in Tennessee Technology Centers

    Science.gov (United States)

    Simpson, Janis Lee

    2013-01-01

    The purpose of this quantitative research study was to determine the degree to which Licensed Practical Nursing programmatic variables positively correlate with select Tennessee Technology Center institution pass rates on the licensure examination--NCLEX-PNRTM. This study investigated the relationship between the dependent variable of NCLEX-PNRTM…

  2. Multiscale time irreversibility of heart rate and blood pressure variability during orthostasis

    International Nuclear Information System (INIS)

    Chladekova, L; Czippelova, B; Turianikova, Z; Tonhajzerova, I; Calkovska, A; Javorka, M; Baumert, M

    2012-01-01

    Time irreversibility is a characteristic feature of non-equilibrium, complex systems such as the cardiovascular control mediated by the autonomic nervous system (ANS). Time irreversibility analysis of heart rate variability (HRV) and blood pressure variability (BPV) represents a new approach to assess cardiovascular regulatory mechanisms. The aim of this paper was to assess the changes in HRV and BPV irreversibility during the active orthostatic test (a balance of ANS shifted towards sympathetic predominance) in 28 healthy young subjects. We used three different time irreversibility indices—Porta’s, Guzik's and Ehler's indices (P%, G% and E, respectively) derived from data segments containing 1000 beat-to-beat intervals on four timescales. We observed an increase in the HRV and a decrease in the BPV irreversibility during standing compared to the supine position. The postural change in irreversibility was confirmed by surrogate data analysis. The differences were more evident in G% and E than P% and for higher scale factors. Statistical analysis showed a close relationship between G% and E. Contrary to this, the association between P% and G% and P% and E was not proven. We conclude that time irreversibility of beat-to-beat HRV and BPV is significantly altered during orthostasis, implicating involvement of the autonomous nervous system in its generation. (paper)

  3. The use of heart rate turbulence and heart rate variability in the assessment of autonomic regulation and circadian rhythm in patients with systemic lupus erythematosus without apparent heart disease.

    Science.gov (United States)

    Poliwczak, A R; Waszczykowska, E; Dziankowska-Bartkowiak, B; Koziróg, M; Dworniak, K

    2018-03-01

    Background Systemic lupus erythematosus is a progressive autoimmune disease. There are reports suggesting that patients even without overt signs of cardiovascular complications have impaired autonomic function. The aim of this study was to assess autonomic function using heart rate turbulence and heart rate variability parameters indicated in 24-hour ECG Holter monitoring. Methods Twenty-six women with systemic lupus erythematosus and 30 healthy women were included. Twenty-four hour ambulatory ECG-Holter was performed in home conditions. The basic parameters of heart rate turbulence and heart rate variability were calculated. The analyses were performed for the entire day and separately for daytime activity and night time rest. Results There were no statistically significant differences in the basic anthropometric parameters. The mean duration of disease was 11.52 ± 7.42. There was a statistically significant higher turbulence onset (To) value in patients with systemic lupus erythematosus, median To = -0.17% (minimum -1.47, maximum 3.0) versus To = -1.36% (minimum -4.53, maximum -0.41), P lupus erythematosus group than in the healthy controls, including SDANN and r-MSSD and p50NN. Concerning the morning activity and night resting periods, the results were similar as for the whole day. In the control group, higher values in morning activity were noted for parameters that characterise sympathetic activity, especially SDANN, and were significantly lower for parasympathetic parameters, including r-MSSD and p50NN, which prevailed at night. There were no statistically significant changes for systemic lupus erythematosus patients for p50NN and low and very low frequency. There was a positive correlation between disease duration and SDNN, R = 0.417; P < 0.05 and SDANN, R = 0.464; P < 0.05, a negative correlation between low/high frequency ratio and r-MSSD, R = -0.454; P < 0.05; p50NN, R = -0.435; P < 0.05 and high frequency

  4. Heart Rate Variability and Wavelet-based Studies on ECG Signals from Smokers and Non-smokers

    Science.gov (United States)

    Pal, K.; Goel, R.; Champaty, B.; Samantray, S.; Tibarewala, D. N.

    2013-12-01

    The current study deals with the heart rate variability (HRV) and wavelet-based ECG signal analysis of smokers and non-smokers. The results of HRV indicated dominance towards the sympathetic nervous system activity in smokers. The heart rate was found to be higher in case of smokers as compared to non-smokers ( p smokers from the non-smokers. The results indicated that when RMSSD, SD1 and RR-mean features were used concurrently a classification efficiency of > 90 % was achieved. The wavelet decomposition of the ECG signal was done using the Daubechies (db 6) wavelet family. No difference was observed between the smokers and non-smokers which apparently suggested that smoking does not affect the conduction pathway of heart.

  5. Evaluation of therapy for dilated cardiomyopathy with heart failure by iodine-123 metaiodobenzyl-guanidine imaging. Comparison with heart rate variability power spectral analysis

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shou-lin; Ikeda, Jun; Takita, Tamotsu; Sekiguchi, Yohei; Demachi, Jun; Chikama, Hisao; Goto, Atsushi; Shirato, Kunio [Tohoku Univ., Sendai (Japan). School of Medicine

    1998-11-01

    The relationship between the myocardial uptake of iodine-123 metaiodobenzylguanidine ({sup 123}I-MIBG) and heart rate variability parameters has not been determined. This study determined the relationship between the change in myocardial uptake of {sup 123}I-MIBG and improvement in left ventricular function after treatment, to determine the usefulness of {sup 123}I-MIBG imaging to assess the effect of therapy on heart failure due to dilated cardiomyopathy (DCM). {sup 123}I-MIBG imaging and power spectral analysis of heart rate variability were performed before and after treatment in 17 patients with heart failure due to DCM. The following parameters were compared before and after treatment: New York Heart Association (NYHA) functional class, radiographic cardiothoracic ratio (CTR), blood pressure, echocardiographic data (left ventricular end-systolic (LVDs) and end-diastolic (LVDd) diameters, left ventricular ejection fraction (LVEF)), plasma concentrations of norepinephrine and epinephrine, heart rate variability power spectral analysis data (mean low frequency (MLF) and high frequency power (MHF)) and the myocardium to mediastinum activity ratio (MYO/M) obtained in early and late images, and washout rate calculated by anterior planar imaging of {sup 123}I-MIBG. The NYHA functional class, LVEF, LVDs, CTR, MLF and MHF improved after treatment. Early MYO/M and late MYO/M improved after treatment. The rate of increase in late MYO/M was positively correlated with the rate of improvement of LVEF after treatment. Furthermore, the late MYO/M was negatively correlated with MLF. Washout rate revealed no correlation with hemodynamic parameters. These findings suggest that late MYO/M is more useful than washout rate to assess the effect of treatment on heart failure due to DCM. Furthermore, the {sup 123}I-MIBG imaging and heart rate variability parameters are useful to assess the autonomic tone in DCM with heart failure. (author)

  6. Evaluation of therapy for dilated cardiomyopathy with heart failure by iodine-123 metaiodobenzyl-guanidine imaging. Comparison with heart rate variability power spectral analysis

    International Nuclear Information System (INIS)

    Li, Shou-lin; Ikeda, Jun; Takita, Tamotsu; Sekiguchi, Yohei; Demachi, Jun; Chikama, Hisao; Goto, Atsushi; Shirato, Kunio

    1998-01-01

    The relationship between the myocardial uptake of iodine-123 metaiodobenzylguanidine ( 123 I-MIBG) and heart rate variability parameters has not been determined. This study determined the relationship between the change in myocardial uptake of 123 I-MIBG and improvement in left ventricular function after treatment, to determine the usefulness of 123 I-MIBG imaging to assess the effect of therapy on heart failure due to dilated cardiomyopathy (DCM). 123 I-MIBG imaging and power spectral analysis of heart rate variability were performed before and after treatment in 17 patients with heart failure due to DCM. The following parameters were compared before and after treatment: New York Heart Association (NYHA) functional class, radiographic cardiothoracic ratio (CTR), blood pressure, echocardiographic data (left ventricular end-systolic (LVDs) and end-diastolic (LVDd) diameters, left ventricular ejection fraction (LVEF)), plasma concentrations of norepinephrine and epinephrine, heart rate variability power spectral analysis data (mean low frequency (MLF) and high frequency power (MHF)) and the myocardium to mediastinum activity ratio (MYO/M) obtained in early and late images, and washout rate calculated by anterior planar imaging of 123 I-MIBG. The NYHA functional class, LVEF, LVDs, CTR, MLF and MHF improved after treatment. Early MYO/M and late MYO/M improved after treatment. The rate of increase in late MYO/M was positively correlated with the rate of improvement of LVEF after treatment. Furthermore, the late MYO/M was negatively correlated with MLF. Washout rate revealed no correlation with hemodynamic parameters. These findings suggest that late MYO/M is more useful than washout rate to assess the effect of treatment on heart failure due to DCM. Furthermore, the 123 I-MIBG imaging and heart rate variability parameters are useful to assess the autonomic tone in DCM with heart failure. (author)

  7. Energy assessment of nitrogen variable rate fertilization on wheat; Analise energetica da aplicacao de nitrogenio em taxa variavel em trigo

    Energy Technology Data Exchange (ETDEWEB)

    Colaco, A.F.; Karam, E.H.; Romanelli, T.L.; Molin, J.P. [Escola Superior de Agricultura Luiz Queiroz (ESALQ/USP), Piracicaba, SP (Brazil). Dept. de Engenharia de Biossistemas], Email: andrecolaco@usp.br; Povh, F.P. [Fundacao ABC Pesquisa e Desenvolvimento Agropecuario, Castro, PR (Brazil)

    2011-07-01

    Precision Agriculture (PA) is a technique that can reduce the inputs utilization in agriculture production, including the nitrogen fertilizer consume. Great importance is given to this fertilizer, due to its contribution on energy input in agriculture. Methodologies based on the calculation of energy flow of agriculture systems are capable to identify management practices that use energy more efficiently. So, this study's objective is to evaluate the variable-rate nitrogen fertilization on wheat, using energy assessment. This study was carried on in two wheat fields, in which the fertilization was done adopting strips alternated by conventional method (single nitrogen dose) and by nitrogen variable-rate technology. Thus, the input and output energy in the system, energy balance, energy return on investment (EROI) and incorporated energy were determined for each geo-referenced point within the fields. Results showed that less energy was demanded when using variable-rate technology, due to the nitrogen saving, providing greater energy balance, EROI and lower incorporated energy on the areas managed using PA. The energy assessment showed to be an important tool to evaluate systems that use PA, because it is capable of monitoring crops energy potential. (author)

  8. Repeatability of heart rate variability in congenital hypothyroidism as analysed by detrended fluctuation analysis

    International Nuclear Information System (INIS)

    Echeverría, J C; Solís, L I; Pérez, J E; Gaitán, M J; Mandujano, M; Sánchez, M C; González-Camarena, R; Rivera, I R

    2009-01-01

    The analysis of heart rate fluctuations, or heart rate variability (HRV), may be applied to explore children's neurodevelopment. However, previous studies have reported poor reliability (repeatability) of HRV measures in children at rest and during light exercise. Whether the reliability can be improved by controlling variables such as physical activity, breathing rate and tidal volume, or by selecting non-conventional techniques for analysing the data remains as an open question. We evaluated the short-term repeatability of RR-interval data from medicated children with congenital hypothyroidism (CH). The α 1 exponents, obtained by detrended fluctuation analysis (DFA), from the data of 21 children collected at two different sessions were compared. Elapsed days between sessions were 59 ± 33, and data were obtained during 10 min, trying to restrict the children's activity while being seated. We found statistical agreement between the means of α 1 exponents for each session (p = 0.94) and no bias with a low-coefficient variation (9.1%); an intraclass correlation coefficient ri = 0.48 ([0.14 0.72], 95% confidence interval) was also estimated. These findings, which were compared with results obtained by conventional time and frequency techniques, indicate the existence of agreement between the α 1 exponents obtained at each session, thereby providing support concerning the repeatability of HRV data as analysed by DFA in children with congenital hypothyroidism. Of particular interest was also the agreement found by using the central frequency of the high-frequency band and the parameter pNN20, both showing better or similar ri than α 1 (0.77 [0.57 0.89] and 0.51 [0.17 0.74], respectively), yet considerably better repeatability than other conventional time and frequency parameters

  9. Thermodynamic consistency of viscoplastic material models involving external variable rates in the evolution equations for the internal variables

    International Nuclear Information System (INIS)

    Malmberg, T.

    1993-09-01

    The objective of this study is to derive and investigate thermodynamic restrictions for a particular class of internal variable models. Their evolution equations consist of two contributions: the usual irreversible part, depending only on the present state, and a reversible but path dependent part, linear in the rates of the external variables (evolution equations of ''mixed type''). In the first instance the thermodynamic analysis is based on the classical Clausius-Duhem entropy inequality and the Coleman-Noll argument. The analysis is restricted to infinitesimal strains and rotations. The results are specialized and transferred to a general class of elastic-viscoplastic material models. Subsequently, they are applied to several viscoplastic models of ''mixed type'', proposed or discussed in the literature (Robinson et al., Krempl et al., Freed et al.), and it is shown that some of these models are thermodynamically inconsistent. The study is closed with the evaluation of the extended Clausius-Duhem entropy inequality (concept of Mueller) where the entropy flux is governed by an assumed constitutive equation in its own right; also the constraining balance equations are explicitly accounted for by the method of Lagrange multipliers (Liu's approach). This analysis is done for a viscoplastic material model with evolution equations of the ''mixed type''. It is shown that this approach is much more involved than the evaluation of the classical Clausius-Duhem entropy inequality with the Coleman-Noll argument. (orig.) [de

  10. Memory-dependent adjustment of vocal response latencies in a territorial songbird.

    Science.gov (United States)

    Geberzahn, Nicole; Hultsch, Henrike; Todt, Dietmar

    2013-06-01

    Vocal interactions in songbirds can be used as a model system to investigate the interplay of intrinsic singing programmes (e.g. influences from vocal memories) and external variables (e.g. social factors). When characterizing vocal interactions between territorial rivals two aspects are important: (1) the timing of songs in relation to the conspecific's singing and (2) the use of a song pattern that matches the rival's song. Responses in both domains can be used to address a territorial rival. This study is the first to investigate the relation of the timing of vocal responses to (1) the vocal memory of a responding subject and (2) the selection of the song pattern that the subject uses as a response. To this end, we conducted interactive playback experiments with adult nightingales (Luscinia megarhynchos) that had been hand-reared and tutored in the laboratory. We analysed the subjects' vocal response latencies towards broadcast playback stimuli that they either had in their own vocal repertoire (songs shared with playback) or that they had not heard before (unknown songs). Likewise, we compared vocal response latencies between responses that matched the stimulus song and those that did not. Our findings showed that the latency of singing in response to the playback was shorter for shared versus unknown song stimuli when subjects overlapped the playback stimuli with their own song. Moreover birds tended to overlap faster when vocally matching the stimulus song rather than when replying with a non-matching song type. We conclude that memory of song patterns influenced response latencies and discuss possible mechanisms. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Simultaneously measured pupillary light reflex and heart rate variability in healthy children

    International Nuclear Information System (INIS)

    Daluwatte, C; Yao, G; Miles, J H

    2012-01-01

    We investigated the potential inter-relationship between two measures of autonomic nervous system: pupillary light reflex (PLR) and heart rate variability (HRV), in healthy children of 8–16 years old. PLR was measured at both dark- and light-adapted conditions with various stimulation intensities. Simultaneously measured HRV was obtained in five different PLR testing phases: before PLR test, light-adapted PLR test, dark adaptation, dark-adapted PLR test and after PLR test. The frequency domain HRV parameters measured during the PLR test were significantly different from those measured during rest. Both the regression analysis and factor analysis indicated that PLR and HRV parameters were not correlated, which suggests that they may provide complementary assessment of different aspects of the overall autonomic nervous system. (paper)

  12. Simultaneously measured pupillary light reflex and heart rate variability in healthy children

    Energy Technology Data Exchange (ETDEWEB)

    Daluwatte, C; Yao, G [Department of Biological Engineering, University of Missouri, Columbia, MO 65211 (United States); Miles, J H, E-mail: YaoG@missouri.edu [Child Health and Thompson Center for Autism and Neurodevelopmental Disorders, University of Missouri, Columbia, MO 65211 (United States)

    2012-06-15

    We investigated the potential inter-relationship between two measures of autonomic nervous system: pupillary light reflex (PLR) and heart rate variability (HRV), in healthy children of 8–16 years old. PLR was measured at both dark- and light-adapted conditions with various stimulation intensities. Simultaneously measured HRV was obtained in five different PLR testing phases: before PLR test, light-adapted PLR test, dark adaptation, dark-adapted PLR test and after PLR test. The frequency domain HRV parameters measured during the PLR test were significantly different from those measured during rest. Both the regression analysis and factor analysis indicated that PLR and HRV parameters were not correlated, which suggests that they may provide complementary assessment of different aspects of the overall autonomic nervous system. (paper)

  13. The Effect of Chicken Extract on Mood, Cognition and Heart Rate Variability

    Directory of Open Access Journals (Sweden)

    Hayley Young

    2015-01-01

    Full Text Available Chicken extract, which is rich in anserine and carnosine, has been widely taken in Asian countries as a traditional remedy with various aims, including attenuation of psychological fatigue. The effects of consuming BRAND’S Essence of Chicken (EOC or a placebo on 46 young adults’ responses to a standard psychological “stressor” were considered. Heart rate variability (HRV, cortisol responses, mood and cognition were measured at baseline and after ten days supplementation. EOC resulted in feeling less anxious, depressed and confused and more agreeable and clearheaded. A decrease in HRV was observed after EOC but only in females. Cognition and cortisol levels were not influenced by EOC. Findings suggest that EOC may be a promising supplement to improve mood in a healthy population.

  14. Continuous multi-parameter heart rate variability analysis heralds onset of sepsis in adults.

    Directory of Open Access Journals (Sweden)

    Saif Ahmad

    Full Text Available BACKGROUND: Early diagnosis of sepsis enables timely resuscitation and antibiotics and prevents subsequent morbidity and mortality. Clinical approaches relying on point-in-time analysis of vital signs or lab values are often insensitive, non-specific and late diagnostic markers of sepsis. Exploring otherwise hidden information within intervals-in-time, heart rate variability (HRV has been documented to be both altered in the presence of sepsis, and correlated with its severity. We hypothesized that by continuously tracking individual patient HRV over time in patients as they develop sepsis, we would demonstrate reduced HRV in association with the onset of sepsis. METHODOLOGY/PRINCIPAL FINDINGS: We monitored heart rate continuously in adult bone marrow transplant (BMT patients (n = 21 beginning a day before their BMT and continuing until recovery or withdrawal (12+/-4 days. We characterized HRV continuously over time with a panel of time, frequency, complexity, and scale-invariant domain techniques. We defined baseline HRV as mean variability for the first 24 h of monitoring and studied individual and population average percentage change (from baseline over time in diverse HRV metrics, in comparison with the time of clinical diagnosis and treatment of sepsis (defined as systemic inflammatory response syndrome along with clinically suspected infection requiring treatment. Of the 21 patients enrolled, 4 patients withdrew, leaving 17 patients who completed the study. Fourteen patients developed sepsis requiring antibiotic therapy, whereas 3 did not. On average, for 12 out of 14 infected patients, a significant (25% reduction prior to the clinical diagnosis and treatment of sepsis was observed in standard deviation, root mean square successive difference, sample and multiscale entropy, fast Fourier transform, detrended fluctuation analysis, and wavelet variability metrics. For infected patients (n = 14, wavelet HRV demonstrated a 25% drop from

  15. Ethnic analogies and differences in fetal heart rate variability signal: A retrospective study.

    Science.gov (United States)

    Tagliaferri, Salvatore; Esposito, Francesca Giovanna; Fagioli, Rosa; Di Cresce, Marco; Sacchi, Lucia; Signorini, Maria Gabriella; Campanile, Marta; Martinelli, Pasquale; Magenes, Giovanni

    2017-02-01

    We aimed to analyze computerized cardiotocographic (cCTG) parameters (including fetal heart rate baseline, short-term variability, Delta, long-term irregularity [LTI], interval index [II], low frequency [LF], movement frequency [MF], high frequency [HF], and approximate entropy [ApEn]) in physiological term pregnancies in order to correlate them with ethnic differences. The clinical meaning of numerical parameters may explain physiological or paraphysiological phenomena that occur in fetuses of different ethnic origins. A total of 696 pregnant women, including 384 from Europe, 246 from sub-Saharan Africa, 45 from South-East Asia, and 21 from South America, were monitored from the 37th to the 41st week of gestation. Statistical analysis was performed with the analysis of variance test, Pearson correlation test and receiver-operator curves (P < 0.05). Our results showed statistically significant differences (P < 0.05) between white and black women for Delta, LTI, LF, MF, HF, and ApEn; between white and Asian women for Delta, LTI, MF, and the LF/(HF + MF) ratio; and between white and Latina women for Delta, LTI, and ApEn. In particular, Delta and LTI performed better in the white group than in the black, Asian, and Latina groups. Instead, LF, MF, HF, and ApEn performed better in the black than in the white group. Our results confirmed the integrity and normal functionality of both central and autonomic nervous system components for all fetuses investigated. Therefore, CTG monitoring should include both linear and nonlinear components of fetal heart rate variability in order to avoid misinterpretations of the CTG trace among ethnic groups. © 2016 Japan Society of Obstetrics and Gynecology.

  16. Depression, anxiety, and heart rate variability: A case-control study in Taiwan

    Directory of Open Access Journals (Sweden)

    Li-Fen Chen

    2014-01-01

    Full Text Available Objective: Decreased heart rate variability (HRV has been reported in persons with major depressive disorder (MDD, but the results obtained are inconsistent. Little is known about the impact of comorbid anxiety disorders on HRV in MDD patients. Both issues necessitate further investigation. Materials and Methods: Forty-nine unmedicated, physically healthy, MDD patients without comorbidity, 21 MDD patients with comorbid generalized anxiety disorder (GAD, 24 MDD patients with comorbid panic disorder (PD, and 81 matched controls were recruited. The Hamilton Depression Rating Scale and the Hamilton Anxiety Rating Scale are employed to assess the severity of depression and anxiety, respectively. The cardiac autonomic function was evaluated by measuring the HRV parameters. The frequency-domain indices of HRV were obtained. Results: MDD patients without comorbidity had lower high-frequency (HF-HRV (which reflected vagal control of HRV than controls. Any comorbid anxiety disorder (GAD or PD was associated with significantly faster heart rates, relative to the controls, and caused greater reductions in HF-HRV among MDD patients. MDD participants with comorbid GAD displayed the greatest reductions in HF-HRV, relative to controls. Correlation analyses revealed that the severity of both depression and anxiety were significantly associated with the mean R wave to R wave (R-R intervals, variance, low-frequency (LF-HRV, and HF-HRV. Conclusion: The present results show decreased HRV in MDD patients, suggesting that reduction in HRV is a psychophysiological marker of MDD. MDD patients with comorbid GAD had the greatest reductions in HRV. Further investigation of the links between MDD and comorbid GAD, HRV, and cardiovascular disease is warranted.

  17. Effects of vegetation, a clay cap and environmental variables on 222Rn fluence rate from reclaimed U mill tailings

    International Nuclear Information System (INIS)

    Morris, R.C.; Fraley, L. Jr.

    1989-01-01

    We measured 222 Rn fluence rate and several environmental variables on two plots with U mill tailings buried beneath 30 cm of overburden and 20 cm of topsoil. An additional 30 cm of clay covered the tailings on one plot and each plot was subdivided into bare soil and vegetated subplots. We used linear correlation, two-way ANOVA and stepwise multiple regression to analyze the effects of the plot characteristics and the environmental variables on 222 Rn fluence rate. The most important effect on 222 Rn fluence rates from these plots was the combination of a clay cap and a vegetated surface. The mean annual fluence rate from the plot having both of these characteristics (520 +/- 370 mBq m-2 s-1) was over three times that of the vegetated plot without a clay cap (170 +/- 130 mBq m-2 s-1) and 18 times that of the bare plot with a clay cap (29 +/- 13 mBq m-2 s-1). The interaction effect may have been due to the growth of roots in the moist clay and active transport of dissolved 222 Rn to the surface in water. This speculation is supported by the observation that on vegetated plots with a clay cap, moisture in the clay enhanced the fluence rate

  18. Heart rate variability and hear left ventricle hypertrophy in clean-up workers after Chernobyl accident with essential hypertension

    International Nuclear Information System (INIS)

    Khomazyuk, Yi.M.; Sidorenko, G.V.

    2004-01-01

    Correlation of heart rate variability (HRV) and hear left ventricle hypertrophy (LVH) in clean-up workers of Chernobyl accident with essential hypertension was estimated. Lowering of total HRV, parasympathetic and sympathetic activity associated with increased range of LVH was discovered

  19. Value of Serial Heart Rate Variability Measurement for Prediction of Appropriate ICD Discharge in Patients with Heart Failure

    NARCIS (Netherlands)

    ten Sande, Judith N.; Damman, Peter; Tijssen, Jan G. P.; de Groot, Joris R.; Knops, Reinoud E.; Wilde, Arthur A. M.; van Dessel, Pascal F. H. M.

    2014-01-01

    HRV and Appropriate ICD Shock in Heart Failure Introduction Decreased heart rate variability (HRV) is associated with adverse outcomes in patients with heart failure. Our objective was to examine whether decreased HRV predicts appropriate implantable cardioverter defibrillator (ICD) shocks. Methods

  20. Heart rate variability response to mental arithmetic stress in patients with schizophrenia Autonomic response to stress in schizophrenia

    NARCIS (Netherlands)

    Castro, Mariana N.; Vigo, Daniel E.; Weidema, Hylke; Fahrer, Rodolfo D.; Chu, Elvina M.; De Achaval, Delfina; Nogues, Martin; Leiguarda, Ramon C.; Cardinali, Daniel P.; Guinjoan, Salvador N.

    Background: The vulnerability-stress hypothesis is an established model of schizophrenia symptom formation. We sought to characterise the pattern of the cardiac autonomic response to mental arithmetic stress in patients with stable schizophrenia. Methods: We performed heart rate variability (HRV)

  1. Resting heart rate, heart rate variability and functional decline in old age

    DEFF Research Database (Denmark)

    Ogliari, Giulia; Mahinrad, Simin; Stott, David J

    2015-01-01

    variability was defined as the standard deviation of normal-to-normal RR intervals (SDNN). Functional status in basic (ADL) and instrumental (IADL) activities of daily living was measured using Barthel and Lawton scales, at baseline and during follow-up. RESULTS: The mean age of the study population was 75...

  2. Timber harvesting with variable prices, costs and interest rates

    International Nuclear Information System (INIS)

    Penttinen, M.

    2000-01-01

    This papers solves the optimal harvesting time problem of a non- industrial private forest (NIPF) owner who typically has a forest management plan and merchantable forest stands. The optimal harvesting time is defined in a volatile market situation. The infinite period problem is also formulated to allow for variable stumpage prices and reforestation costs in a two-period framework, the first of which covers the near future with dynamic price and cost functions and the second the rest of the infinite future with trend price and cost functions. The existence and uniqueness of an optimal policy is demonstrated on the basis of the explicit quasi- concavity of the objective functions. First, the solutions are constructed with prices and costs dependent on stand age only. Both cases in which the same prices and costs hold for all periods and cases in which there are dynamic prices and costs in the first period and trend ones in subsequent periods are considered. Second, the age-dependent functions are multiplied separately by the calendar time dependent exponential terms. Solutions are provided both in the case with the same age-dependent functions and the case with dynamic functions for the first period and trend functions for the subsequent periods. The sensitivity and comparative static analyses are studied with respect to the interest rate, price and cost changes, both analytically and numerically. Optimal rotation solutions are presented with alternative competing volume growth functions. Final results are provided by a gross income growth function. Competing optimisation models are discussed, and alternative volume growth models and a value growth model are compared. The key notion of the research is the sensitivity and comparative static analysis of the optimal rotation solutions with respect to roundwood prices, reforestation costs and interest rates. Different local market parameter and alternative growth data estimates are applied in testing the impact of

  3. Hypnosis in the Treatment of Major Depression: An Analysis of Heart Rate Variability.

    Science.gov (United States)

    Chen, Xiuwen; Yang, Rongqian; Ge, Lulu; Luo, Jie; Lv, Ruixue

    2017-01-01

    Hypnosis is an adjuvant treatment of major depression (MD). Heart rate variability (HRV) can assess the autonomic nervous system, which is associated with MD, and HRV is decreased in MD patients. There is a lack of research on HRV changes before, during, and after the use of hypnosis in MD patients. A total of 21 MD patients participated in this study, and 5-minute electrocardiograms were recorded before, during, and after hypnosis. Compared with the prehypnotic condition, HRV parameters significantly (p hypnosis treatment should bring some functional improvement to the autonomic nervous system. HRV is potentially a useful tool that quantifies the physiological impact of hypnosis treatment in MD patients.

  4. Inferring clocks when lacking rocks: the variable rates of molecular evolution in bacteria

    Directory of Open Access Journals (Sweden)

    Ochman Howard

    2009-09-01

    Full Text Available Abstract Background Because bacteria do not have a robust fossil record, attempts to infer the timing of events in their evolutionary history requires comparisons of molecular sequences. This use of molecular clocks is based on the assumptions that substitution rates for homologous genes or sites are fairly constant through time and across taxa. Violation of these conditions can lead to erroneous inferences and result in estimates that are off by orders of magnitude. In this study, we examine the consistency of substitution rates among a set of conserved genes in diverse bacterial lineages, and address the questions regarding the validity of molecular dating. Results By examining the evolution of 16S rRNA gene in obligate endosymbionts, which can be calibrated by the fossil record of their hosts, we found that the rates are consistent within a clade but varied widely across different bacterial lineages. Genome-wide estimates of nonsynonymous and synonymous substitutions suggest that these two measures are highly variable in their rates across bacterial taxa. Genetic drift plays a fundamental role in determining the accumulation of substitutions in 16S rRNA genes and at nonsynonymous sites. Moreover, divergence estimates based on a set of universally conserved protein-coding genes also exhibit low correspondence to those based on 16S rRNA genes. Conclusion Our results document a wide range of substitution rates across genes and bacterial taxa. This high level of variation cautions against the assumption of a universal molecular clock for inferring divergence times in bacteria. However, by applying relative-rate tests to homologous genes, it is possible to derive reliable local clocks that can be used to calibrate bacterial evolution. Reviewers This article was reviewed by Adam Eyre-Walker, Simonetta Gribaldo and Tal Pupko (nominated by Dan Graur.

  5. Heart Rate and Systolic Blood Pressure Variability on Recently Diagnosed Diabetics

    Directory of Open Access Journals (Sweden)

    Anaclara Michel-Chávez

    2015-01-01

    Full Text Available Background: Diabetes affects approximately 250 million people in the world. Cardiovascular autonomic neuropathy is a common complication of diabetes that leads to severe postural hypotension, exercise intolerance, and increased incidence of silent myocardial infarction. Objective: To determine the variability of heart rate (HR and systolic blood pressure (SBP in recently diagnosed diabetic patients. Methods: The study included 30 patients with a diagnosis of type 2 diabetes of less than 2 years and 30 healthy controls. We used a Finapres® device to measure during five minutes beat-to-beat HR and blood pressure in three experimental conditions: supine position, standing position, and rhythmic breathing at 0.1 Hz. The results were analyzed in the time and frequency domains. Results: In the HR analysis, statistically significant differences were found in the time domain, specifically on short-term values such as standard deviation of NN intervals (SDNN, root mean square of successive differences (RMSSD, and number of pairs of successive NNs that differ by more than 50 ms (pNN50. In the BP analysis, there were no significant differences, but there was a sympathetic dominance in all three conditions. The baroreflex sensitivity (BRS decreased in patients with early diabetes compared with healthy subjects during the standing maneuver. Conclusions: There is a decrease in HR variability in patients with early type 2 diabetes. No changes were observed in the BP analysis in the supine position, but there were changes in BRS with the standing maneuver, probably due to sympathetic hyperactivity.

  6. Variety is not the spice of life for people with autism spectrum disorders: frequency ratings of central, variable and inappropriate aspects of common real-life events.

    Science.gov (United States)

    Loth, Eva; Happé, Francesca; Gómez, Juan Carlos

    2010-06-01

    This study used a novel rating task to investigate whether high-functioning individuals with autism spectrum disorder (ASD) have difficulties distinguishing essential from variable aspects of familiar events. Participants read stories about everyday events and judged how often central, variable, and inappropriate event-components normally occur in this type of situation. The ASD boys made significantly more errors than the typically developing boys in rating the occurrences of variable aspects. In both groups, ratings of variable aspects were age-related, but in the ASD boys, they were also related to theory of mind and weak coherence test scores, and to severity of autistic symptoms. Implications for the understanding of some repetitive behaviours, such as the tendency to adhere to inflexible routines, are discussed.

  7. Changes in cortisol release and heart rate variability in sport horses during long-distance road transport.

    Science.gov (United States)

    Schmidt, A; Biau, S; Möstl, E; Becker-Birck, M; Morillon, B; Aurich, J; Faure, J-M; Aurich, C

    2010-04-01

    It is widely accepted that transport is stressful for horses, but only a few studies are available involving horses that are transported regularly and are accustomed to transport. We determined salivary cortisol immunoreactivity (IR), fecal cortisol metabolites, beat-to-beat (RR) interval, and heart rate variability (HRV) in transport-experienced horses (N=7) in response to a 2-d outbound road transport over 1370 km and 2-d return transport 8 d later. Salivary cortisol IR was low until 60 min before transport but had increased (PHRV variable standard deviation 2 (SD2) occurred (PHRV, which is indicative of stress. The degree of these changes tended to be most pronounced on the first day of both outbound and return transport. Copyright 2009 Elsevier Inc. All rights reserved.

  8. Physical Exercise Improves Heart Rate Variability in Patients with Type 2 Diabetes: A Systematic Review.

    Science.gov (United States)

    Villafaina, Santos; Collado-Mateo, Daniel; Fuentes, Juan Pedro; Merellano-Navarro, Eugenio; Gusi, Narcis

    2017-09-23

    The aim of the present systematic review is to provide an up-to-date analysis of the research on the effects of exercise programs on heart rate variability (HRV) in individuals with type 2 diabetes mellitus (T2DM). An electronic search of the literature (PubMed, PEDro and Web of Science) was performed. "HRV", "heart rate variability", "exercise", "physical" and "diabetes" were the terms used for article retrieval. Lastly, 15 articles were selected. PRISMA methodology was employed and data were extracted according to the PICOS approach. Although HRV is not routinely measured in the management of T2DM, it is an important measure due to its relation with mortality and diabetic neuropathy. Physical exercise has become a therapy for T2DM, because it improves physical fitness and functional capacity, enhances metabolic control and insulin sensitivity, reduces inflammatory markers and neuropathy symptoms and can increase the regenerative capacity of cutaneous axons, slowing or preventing neuropathy progression. However, it is not clear to what extent physical exercise can improve HRV in this population. Participation in the 15 selected studies was similar in men and women (48.01% men and 51.99% women). All the intervention programs included aerobic training, and it was complemented by strength training in four studies. Duration of physical exercise sessions ranged between 30 and 75 min, the frequency being between 2 and 7 days/week. Statistically significant improvements in groups with diabetes, relative to baseline, were observed in nine studies. More than 3 days per week of aerobic training, complemented by strength training, during at least 3 months seems to improve HRV in T2DM. Weekly frequency might be the most important factor to improve HRV. These aspects could help to design better programs based in scientific evidence, incorporating HRV as an important variable associated with diabetic neuropathy and mortality.

  9. Do bells affect behaviour and heart rate variability in grazing dairy cows?

    Directory of Open Access Journals (Sweden)

    Julia Johns

    Full Text Available In alpine regions cows are often equipped with bells. The present study investigated the impact of wearing a bell on behaviour and heart rate variability in dairy cows. Nineteen non-lactating Brown-Swiss cows with bell experience were assigned to three different treatments. For 3 days each, cows were equipped with no bell (control, with a bell with inactivated clapper (silent bell or with a functional bell (functional bell. The bells weighed 5.5 kg and had frequencies between 532 Hz and 2.8 kHz and amplitudes between 90 and 113 dB at a distance of 20 cm. Data were collected on either the first and third or on all 3 days of each treatment. Whereas duration of rumination was reduced with a functional bell and a silent bell compared with no bell, feeding duration was reduced with a silent bell and was intermediate with a functional bell. Head movements were reduced when wearing a silent bell compared with no bell and tended to be reduced when wearing a functional compared to no bell. With a functional bell, lying duration was reduced by almost 4 hours on the third day of treatment compared with the first day with a functional bell and compared with no bell or a silent bell. All additional behavioural measures are consistent with the hypothesis of a restriction in the behaviour of the cows wearing bells, although this pattern did not reach significance. There was no treatment effect on heart rate variability, suggesting that the bells did not affect vago-sympathetic balance. An effect of experimental day was found for only 1 out of 10 behavioural parameters, as shown by a decrease in lying with a functional bell on day 3. The results indicate behavioural changes in the cows wearing a bell over 3 days, without indication of habituation to the bell. Altogether, the behavioural changes suggest that the behaviour of the cows was disturbed by wearing a bell. If long-lasting, these effects may have implications for animal welfare.

  10. Effects of awareness and nociception on heart rate variability during general anaesthesia

    International Nuclear Information System (INIS)

    Huhle, R; Zaunseder, S; Malberg, H; Burghardt, M; Koch, T; Heller, A R; Wessel, N

    2012-01-01

    During anaesthesia awareness and nociception are serious complications that may further lead to haemodynamic instability. Specific monitoring of depth of hypnosis and depth of analgesia based on heart rate variability (HRV) analysis is eligible to improve patient safety and reduce efforts in post-operative care. Consequently, in this analysis we assess the applicability of HRV parameters during surgical interventions with standardized intravenous propofol-remifentanil-anaesthesia. Peri-operative electrocardiograms were recorded from cardiovascular stable patients (ASA Score I/II, N = 32, age: 36.4 ± 11.23 a, BMI: 25.2 ± 3.16) scheduled for trauma and dentofacial surgery. HRV time- and frequency-domain parameters, measures of complexity and nonlinear dynamics were compared by analysing longitudinally distributed 300 s intervals preceding/following induction of anaesthesia (BL–I1), intubation (I1–I2) and extubation (E1–E2). Mean value (meanNN) and standard deviation (sdNN) of the heart rate are influenced in BL–I1 (p < 0.001), I1–I2 (p < 0.05) and E1–E2 (p < 0.001). The number of forbidden words of symbolic dynamics changes significantly for BL–I1 (p < 0.001) and not for I1–I2 and E1–E2 (p > 0.05). Probability of low-variability POLVAR10 is significantly altered in all comparisons (BL–I1: Δ = 0.032, p < 0.01, I1–I2: Δ = 0.12, p < 0.05, E1–E2: Δ = 0.169, p < 0.01) but especially during nociception. While standard time-domain parameters lacked selectivity, parameters of symbolic dynamics appear to be specifically influenced by changes in depth of hypnosis and nociception, respectively. However, the lack of steady-state ventilation/breathing in this study needs to be considered in future research. To be used for clinical anaesthesia monitoring our results have to be prospectively validated in clinical studies. (paper)

  11. Do Bells Affect Behaviour and Heart Rate Variability in Grazing Dairy Cows?

    Science.gov (United States)

    Johns, Julia; Patt, Antonia; Hillmann, Edna

    2015-01-01

    In alpine regions cows are often equipped with bells. The present study investigated the impact of wearing a bell on behaviour and heart rate variability in dairy cows. Nineteen non-lactating Brown-Swiss cows with bell experience were assigned to three different treatments. For 3 days each, cows were equipped with no bell (control), with a bell with inactivated clapper (silent bell) or with a functional bell (functional bell). The bells weighed 5.5 kg and had frequencies between 532 Hz and 2.8 kHz and amplitudes between 90 and 113 dB at a distance of 20 cm. Data were collected on either the first and third or on all 3 days of each treatment. Whereas duration of rumination was reduced with a functional bell and a silent bell compared with no bell, feeding duration was reduced with a silent bell and was intermediate with a functional bell. Head movements were reduced when wearing a silent bell compared with no bell and tended to be reduced when wearing a functional compared to no bell. With a functional bell, lying duration was reduced by almost 4 hours on the third day of treatment compared with the first day with a functional bell and compared with no bell or a silent bell. All additional behavioural measures are consistent with the hypothesis of a restriction in the behaviour of the cows wearing bells, although this pattern did not reach significance. There was no treatment effect on heart rate variability, suggesting that the bells did not affect vago-sympathetic balance. An effect of experimental day was found for only 1 out of 10 behavioural parameters, as shown by a decrease in lying with a functional bell on day 3. The results indicate behavioural changes in the cows wearing a bell over 3 days, without indication of habituation to the bell. Altogether, the behavioural changes suggest that the behaviour of the cows was disturbed by wearing a bell. If long-lasting, these effects may have implications for animal welfare. PMID:26110277

  12. The relationship between emotion regulation capacity, heart rate variability, and quality of life in individuals with alcohol-related brain damage

    Directory of Open Access Journals (Sweden)

    Steinmetz JP

    2016-08-01

    Full Text Available Jean-Paul Steinmetz,1,2 Claus Vögele,3,4 Christiane Theisen-Flies,5 Carine Federspiel,1,2 Stefan Sütterlin6,7 1Department of Research and Development, ZithaSenior, 2Centre for Memory and Mobility, ZithaSenior, 3Institute for Health and Behaviour, Integrative Research Unit on Social and Individual Development (INSIDE, University of Luxembourg, Luxembourg; 4Research Group Health Psychology, University of Leuven, Leuven, Belgium; 5Home St Joseph, ZithaSenior, Luxembourg; 6Department of Psychology, Lillehammer University College, Lillehammer, 7Division of Surgery and Clinical Neuroscience, Department of Psychosomatic Medicine, Oslo University Hospital – Rikshospitalet, Oslo, Norway Abstract: The reliable measurement of quality of life (QoL presents a challenge in individuals with alcohol-related brain damage. This study investigated vagally mediated heart rate variability (vmHRV as a physiological predictor of QoL. Self- and proxy ratings of QoL and dysexecutive symptoms were collected once, while vmHRV was repeatedly assessed over a 3-week period at weekly intervals in a sample of nine alcohol-related brain damaged patients. We provide robustness checks, bootstrapped correlations with confidence intervals, and standard errors for mean scores. We observed low to very low heart rate variability scores in our patients in comparison to norm values found in healthy populations. Proxy ratings of the QoL scale “subjective physical and mental performance” and everyday executive dysfunctions were strongly related to vmHRV. Better proxy-rated QoL and fewer dysexecutive symptoms were observed in those patients with higher vmHRV. Overall, patients showed low parasympathetic activation favoring the occurrence of dysfunctional emotion regulation strategies. Keywords: heart rate variability, emotion regulation, alcohol-related brain damage, quality of life

  13. Effect of Dietary Omega-3 Polyunsaturated Fatty Acids on Heart Rate and Heart Rate Variability in Animals Susceptible or Resistant to Ventricular Fibrillation

    Directory of Open Access Journals (Sweden)

    George E Billman

    2012-03-01

    Full Text Available The consumption of omega-3 polyunsaturated fatty acids (n-3 PUFAs has been reported to reduce cardiac mortality following myocardial infarction as well as to decrease resting heart rate (HR and increase heart rate variability (HRV. However, it has not been established whether n-3 PUFAs exhibit the same actions on HR and HRV in individuals known to be either susceptible or resistant to ventricular fibrillation (VF. Therefore, HR and HRV (high frequency and total R-R interval variability were evaluated before and 3 months after n-3 PUFA treatment in dogs with healed myocardial infarction that were either susceptible (VF+, n = 31 or resistant (VF-, n = 31 to ventricular tachyarrhythmias induced by a 2 min coronary artery occlusion during the last minute of a submaximal exercise test. HR and HRV were evaluated at rest, during submaximal exercise and in response to acute myocardial ischemia at rest before and after either placebo (1 g/day, corn oil, VF+, n = 9; VF- n = 8 or n-3 PUFA (docosahexaenoic acid + eicosapentaenoic acid ethyl esters, 1-4g/day, VF+, n = 22; VF-, n = 23 treatment for 3 months. The n-3 PUFA treatment elicited similar increases in red blood cell membrane, right atrial, and left ventricular n-3 PUFA levels in both the VF+ and VF- dogs. The n-3 PUFA treatment also provoked similar reductions in baseline HR and increases in baseline HRV in both groups that resulted in parallel shifts in the response to either exercise or acute myocardial ischemia (that is, the change in these variables induced by physiological challenges was not altered after n-3 PUFA treatment. These data demonstrate that dietary n-3 PUFA decreased HR and increased HRV to a similar extent in animals known to be prone to or resistant to malignant cardiac tachyarrhythmias.

  14. Heart rate variability in adolescents with functional hypothalamic amenorrhea and anorexia nervosa.

    Science.gov (United States)

    Bomba, Monica; Corbetta, Fabiola; Gambera, Alessandro; Nicosia, Franco; Bonini, Luisa; Neri, Francesca; Tremolizzo, Lucio; Nacinovich, Renata

    2014-02-28

    Aim of this study consisted in assessing the 24-h heart rate variability (HRV), a measure of autonomic nervous system (ANS) imbalance, in 21 adolescents with functional hypothalamic amenorrhea (FHA, 11 normogonadotropic, N-FHA, and 10 hypogonadotropic, Hy-FHA) compared to 21 patients with anorexia nervosa (AN) and 21 controls. As expected, subjects with AN showed a significant dysregulation in multiple HRV parameters, while Hy-FHA patients presented with a dysregulation in a few domains (SDNN, HFr), which was not present in girls with N-FHA, who showed values largely similar to controls. FHA might represent part of the AN biological spectrum, and a link between these two conditions might exist, possibly related to the degree of psychological and/or hormonal dysfunction. © 2013 Published by Elsevier Ireland Ltd.

  15. Comparison of two systems for long-term heart rate variability monitoring in free-living conditions - a pilot study

    DEFF Research Database (Denmark)

    Kristiansen, Jesper; Korshoj, Mette; Skotte, Jorgen H

    2011-01-01

    Actiheart and Holter recorders, and signals were processed to RR-interval time series. Segments of 5-minute duration were sampled every 30 minutes, and spectral components of the heart rate variability were calculated. Actiheart and Holter values were compared using Deming regression analysis and Bland...

  16. The Effect of Sex on Heart Rate Variability at High Altitude.

    Science.gov (United States)

    Boos, Christopher John; Vincent, Emma; Mellor, Adrian; O'Hara, John; Newman, Caroline; Cruttenden, Richard; Scott, Phylip; Cooke, Mark; Matu, Jamie; Woods, David Richard

    2017-12-01

    There is evidence suggesting that high altitude (HA) exposure leads to a fall in heart rate variability (HRV) that is linked to the development of acute mountain sickness (AMS). The effects of sex on changes in HRV at HA and its relationship to AMS are unknown. HRV (5-min single-lead ECG) was measured in 63 healthy adults (41 men and 22 women) 18-56 yr of age at sea level (SL) and during a HA trek at 3619, 4600, and 5140 m, respectively. The main effects of altitude (SL, 3619 m, 4600 m, and 5140 m) and sex (men vs women) and their potential interaction were assessed using a factorial repeated-measures ANOVA. Logistic regression analyses were performed to assess the ability of HRV to predict AMS. Men and women were of similar age (31.2 ± 9.3 vs 31.7 ± 7.5 yr), ethnicity, and body and mass index. There was main effect for altitude on heart rate, SD of normal-to-normal (NN) intervals (SDNN), root mean square of successive differences (RMSSD), number of pairs of successive NN differing by >50 ms (NN50), NN50/total number of NN, very low-frequency power, low-frequency (LF) power, high-frequency (HF) power, and total power (TP). The most consistent effect on post hoc analysis was reduction in these HRV measures between 3619 and 5140 m at HA. Heart rate was significantly lower and SDNN, RMSSD, LF power, HF power, and TP were higher in men compared with women at HA. There was no interaction between sex and altitude for any of the HRV indices measured. HRV was not predictive of AMS development. Increasing HA leads to a reduction in HRV. Significant differences between men and women emerge at HA. HRV was not predictive of AMS.

  17. Heart Rate Variability Is Associated with Exercise Capacity in Patients with Cardiac Syndrome X.

    Directory of Open Access Journals (Sweden)

    Dai-Yin Lu

    Full Text Available Heart rate variability (HRV reflects the healthiness of autonomic nervous system, which is associated with exercise capacity. We therefore investigated whether HRV could predict the exercise capacity in the adults with cardiac syndrome X (CSX. A total of 238 subjects (57±12 years, 67.8% men, who were diagnosed as CSX by the positive exercise stress test and nearly normal coronary angiogram were enrolled. Power spectrum from the 24-hour recording of heart rate was analyzed in frequency domain using total power (TP and spectral components of the very low frequency (VLF, low frequency (LF and high frequency (HF ranges. Among the study population, 129 subjects with impaired exercise capacity during the treadmill test had significantly lower HRV indices than those with preserved exercise capacity (≥90% of the age predicted maximal heart rate. After accounting for age, sex, and baseline SBP and heart rate, VLF (odds ratio per 1SD and 95% CI: 2.02, 1.19-3.42, LF (1.67, 1.10-2.55, and TP (1.82, 1.17-2.83 remained significantly associated with preserved exercise capacity. In addition, increased HRV indices were also associated with increased exercise duration, rate-pressure product, and heart rate recovery, independent of age, body mass index, and baseline SBP and heart rate. In subgroup analysis, HRV indices demonstrated similar predictive values related to exercise capacity across various subpopulations, especially in the young. In patients with CSX, HRV was independently associated with exercise capacity, especially in young subjects. The healthiness of autonomic nervous system may have a role in modulating the exercise capacity in patients with CSX.

  18. Assessment of volumetric-modulated arc therapy for constant and variable dose rates

    Directory of Open Access Journals (Sweden)

    Mariluz De Ornelas-Couto

    2017-01-01

    Full Text Available Purpose: The aim of this study is to compare the effects of dose rate on volumetric-modulated arc therapy plans to determine optimal dose rates for prostate and head and neck (HN cases. Materials and Methods: Ten prostate and ten HN cases were retrospectively studied. For each case, seven plans were generated: one variable dose rate (VDR and six constant dose rate (CDR (100–600 monitor units [MUs]/min plans. Prescription doses were: 80 Gy to planning target volume (PTV for the prostate cases, and 70, 60, and 54 Gy to PTV1, PTV2, and PTV3, respectively, for HN cases. Plans were normalized to 95% of the PTV and PTV1, respectively, with the prescription dose. Plans were assessed using Dose-Volume-Histogram metrics, homogeneity index, conformity index, MUs, and delivery time. Results: For the prostate cases, significant differences were found for rectum D35 between VDR and all CDR plans, except CDR500. Furthermore, VDR was significantly different than CDR100 and 200 for bladder D50. Delivery time for all CDR plans and MUs for CDR400–600 were significantly higher when compared to VDR. HN cases showed significant differences between VDR and CDR100, 500 and 600 for D2 to the cord and brainstem. Significant differences were found for delivery time and MUs for all CDR plans, except CDR100 for number of MUs. Conclusion: The most significant differences were observed in delivery time and number of MUs. All-in-all, the best CDR for prostate cases was found to be 300 MUs/min and 200 or 300 MUs/min for HN cases. However, VDR plans are still the choice in terms of MU efficiency and plan quality.

  19. Autonomic modulations of heart rate variability are associated with sports injury incidence in sprint swimmers.

    Science.gov (United States)

    Lima-Borges, Dayanne S; Martinez, Paula F; Vanderlei, Luiz Carlos M; Barbosa, Fernando S S; Oliveira-Junior, Silvio A

    2018-03-28

    Young athletes' participation in competitive sports is becoming increasingly common, and this increased involvement raises concerns about the occurrence of overtraining and sports injuries. Since these issues are poorly understood, this study analyzed heart rate variability, stress/recovery relationship, and sports injury incidence during a training macrocycle of young sprint and endurance swimmers. Thirty teenage swimmers (aged 12 to 17 years) were divided into two groups as follows: Sprint (n = 17) and Endurance (n = 13). Subjects were evaluated over 20 weeks, based on the following three schedules: general, specific, and competitive. In addition to heart rate variability and sports injury incidence, the Recovery-Stress-Questionnaire of Athletes was used to analyse stress/recovery states in athletes. All procedures were developed at the initial moment and at the end of each periodization step. The Sprint group presented a reduced standard deviation of normal-normal beats (73.0 ± 6.6 vs. 54.1 ± 3.5 ms; p sports injury than the Endurance group (0.0214 ± 0.0068 vs. 0.0136 ± 0.0050 cases/1000 hours). Sprint training was associated with progressive activation of the sympathetic nervous system as well as a higher incidence of sports injury in comparison to endurance swimming during a training macrocycle.

  20. Heart Rate Variability Analysis in Patients with Allergic Rhinitis

    Directory of Open Access Journals (Sweden)

    Ming-Ying Lan

    2013-01-01

    Full Text Available Background. Very few studies investigate the role of the autonomic nervous system in allergic rhinitis. In this study, we evaluated the autonomic nervous system in allergic rhinitis patients using heart rate variability (HRV analysis. Methods. Eleven patients with allergic rhinitis and 13 healthy controls, aged between 19 and 40 years old, were enrolled in the study. Diagnosis of allergic rhinitis was based on clinical history, symptoms, and positive Phadiatop test. Electrocardiographic recordings on the sitting and supine positions were obtained for HRV analysis. Results. In the supine position, there were no significant statistical differences in very-low-frequency power (VLF, ≤0.04 Hz, low-frequency power (LF, 0.04–0.15 Hz, high-frequency power (HF, 0.15–0.40 Hz, and the ratio of LF to HF (LF/HF between the patient and control groups. The mean RR intervals significantly increased, while LF% and LF/HF significantly decreased in the patient group in the sitting position. Moreover, mean RR intervals, LF, and LF/HF, which were significantly different between the two positions in the control group, did not show a significant change with the posture change in the patient group. Conclusion. These suggest that patients with allergic rhinitis may have poor sympathetic modulation in the sitting position. Autonomic dysfunction may therefore play a role in the pathophysiology of allergic rhinitis.

  1. [Spectral analysis of Heart Rate Variability in psychiatric patients: autonomic nervous system evaluation in psychotic, anxiety and depressive disorders].

    Science.gov (United States)

    Lo Turco, Giovanni; Grimaldi Di Terresena, Liria

    2012-01-01

    The aim of this study was to test the primary hypothesis of altered Heart Rate Variability (HRV) and heart rate in a sample of patients with mental disorders and the secondary hypothesis of normalization of HRV values as a result of clinical improvement. The study was conducted on a sample of 90 patients with psychotic, anxiety and mood disorders. Each patient was subjected to detection of HRV and heart rate via a photoplethysmographic sensor and evaluated with rating scales based on the specific disorder. The parameters detected in the sample were compared with a control group of healthy subjects. There were no significant differences of cardiac autonomic modulation between the group of patients in whom is possible exclude the drug influence and the control group; significantly lower values of HRV parameters in the group of patients with drug influence, and especially in subgroup of psychotic patients, compared to controls, are, instead, detected. The study also shows a significant increase in heart rate as a common feature in mental disorders, regardless of treatment. Clinical improvement appears to promote the normalization of the variability in patients with high DS of tachogram. The study suggests a potential increased risk of cardiovascular mortality in patients, as evidenced by the increased values of heart rate, regardless of drug treatment. This risk is even more pronounced in psychotic patients in drug treatment because of the simultaneous significant reduction of HRV parameters.

  2. GLP-1 receptor stimulation depresses heart rate variability and inhibits neurotransmission to cardiac vagal neurons.

    Science.gov (United States)

    Griffioen, Kathleen J; Wan, Ruiqian; Okun, Eitan; Wang, Xin; Lovett-Barr, Mary Rachael; Li, Yazhou; Mughal, Mohamed R; Mendelowitz, David; Mattson, Mark P

    2011-01-01

    glucagon-like peptide 1 (GLP-1) is an incretin hormone released from the gut in response to food intake. Whereas GLP-1 acts in the periphery to inhibit glucagon secretion and stimulate insulin release, it also acts in the central nervous system to mediate autonomic control of feeding, body temperature, and cardiovascular function. Because of its role as an incretin hormone, GLP-1 receptor analogs are used as a treatment for type 2 diabetes. Central or peripheral administration of GLP-1 increases blood pressure and heart rate, possibly by activating brainstem autonomic nuclei and increasing vagus nerve activity. However, the mechanism(s) by which GLP-1 receptor stimulation affects cardiovascular function are unknown. We used the long-lasting GLP-1 receptor agonist Exendin-4 (Ex-4) to test the hypothesis that GLP-1 signalling modulates central parasympathetic control of heart rate. using a telemetry system, we assessed heart rate in mice during central Ex-4 administration. Heart rate was increased by both acute and chronic central Ex-4 administration. Spectral analysis indicated that the high frequency and low frequency powers of heart rate variability were diminished by Ex-4 treatment. Finally, Ex-4 decreased both excitatory glutamatergic and inhibitory glycinergic neurotransmission to preganglionic parasympathetic cardiac vagal neurons. these data suggest that central GLP-1 receptor stimulation diminishes parasympathetic modulation of the heart thereby increasing heart rate.

  3. Features of Heart Rate Variability Capture Regulatory Changes During Kangaroo Care in Preterm Infants.

    Science.gov (United States)

    Kommers, Deedee R; Joshi, Rohan; van Pul, Carola; Atallah, Louis; Feijs, Loe; Oei, Guid; Bambang Oetomo, Sidarto; Andriessen, Peter

    2017-03-01

    To determine whether heart rate variability (HRV) can serve as a surrogate measure to track regulatory changes during kangaroo care, a period of parental coregulation distinct from regulation within the incubator. Nurses annotated the starting and ending times of kangaroo care for 3 months. The pre-kangaroo care, during-kangaroo care, and post-kangaroo care data were retrieved in infants with at least 10 accurately annotated kangaroo care sessions. Eight HRV features (5 in the time domain and 3 in the frequency domain) were used to visually and statistically compare the pre-kangaroo care and during-kangaroo care periods. Two of these features, capturing the percentage of heart rate decelerations and the extent of heart rate decelerations, were newly developed for preterm infants. A total of 191 kangaroo care sessions were investigated in 11 preterm infants. Despite clinically irrelevant changes in vital signs, 6 of the 8 HRV features (SD of normal-to-normal intervals, root mean square of the SD, percentage of consecutive normal-to-normal intervals that differ by >50 ms, SD of heart rate decelerations, high-frequency power, and low-frequency/high-frequency ratio) showed a visible and statistically significant difference (P heart rate decelerations. HRV-based features may be clinically useful for capturing the dynamic changes in autonomic regulation in response to kangaroo care and other changes in environment and state. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Non-linear indices of heart rate variability during endodontic treatment.

    Science.gov (United States)

    Santana, Milana Drumond Ramos; Pita Neto, Ivo Cavalcante; Martiniano, Eli Carlos; Monteiro, Larissa Raylane Lucas; Ramos, José Lucas Souza; Garner, David M; Valenti, Vitor Engácia; Abreu, Luiz Carlos de

    2016-01-01

    Dental treatment promotes psychosomatic change that can influence the procedure and compromise the general well-being of the patient. In this context, it highlights the importance of evaluating the function of the autonomic nervous system in individuals undergoing endodontic treatment. Thus, this manuscript aimed to analyse cardiac autonomic modulation, through non-linear indices of heart rate variability (HRV) during endodontic treatment. Analysis of 50 subjects of either sex aged between 18 and 40 years diagnosed with irreversible pulp necrosis of lower molars undergoing endodontic treatment was undertaken. We carried out fractal and symbolic analysis of HRV, which was recorded in the first session of the endodontic treatment at four intervals: T1: 0-10 min before the onset of the treatment session; T2: 0-10 min after the application of anaesthesia; T3: throughout the period of treatment; and T4: 0-30 min after the end of the treatment session. There was reduction of α1 in T2 compared to T1 and T4 (p endodontic treatment, and after applying local anaesthetic the parasympathetic component of HRV increases. These data indicate that endodontic treatment acutely overcharges the heart, supporting the stress involved in this situation.

  5. Heart rate variability: a tool to explore the sleeping brain?

    Directory of Open Access Journals (Sweden)

    Florian eChouchou

    2014-12-01

    Full Text Available Sleep is divided into two main sleep stages: 1 non-rapid eye movement sleep (non-REMS, characterized among others by reduced global brain activity; and 2 rapid eye movement sleep (REMS, characterized by global brain activity similar to that of wakefulness. Results of heart rate variability (HRV analysis, which is widely used to explore autonomic modulation, have revealed higher parasympathetic tone during normal non-REMS and a shift toward sympathetic predominance during normal REMS. Moreover, HRV analysis combined with brain imaging has identified close connectivity between autonomic cardiac modulation and activity in brain areas such as the amygdala and insular cortex during REMS, but no connectivity between brain and cardiac activity during non-REMS. There is also some evidence for an association between HRV and dream intensity and emotionality. Following some technical considerations, this review addresses how brain activity during sleep contributes to changes in autonomic cardiac activity, organized into three parts: 1 the knowledge on autonomic cardiac control, 2 differences in brain and autonomic activity between non-REMS and REMS, and 3 the potential of HRV analysis to explore the sleeping brain, and the implications for psychiatric disorders.

  6. Heart rate variability (HRV): an indicator of stress

    Science.gov (United States)

    Kaur, Balvinder; Durek, Joseph J.; O'Kane, Barbara L.; Tran, Nhien; Moses, Sophia; Luthra, Megha; Ikonomidou, Vasiliki N.

    2014-05-01

    Heart rate variability (HRV) can be an important indicator of several conditions that affect the autonomic nervous system, including traumatic brain injury, post-traumatic stress disorder and peripheral neuropathy [3], [4], [10] & [11]. Recent work has shown that some of the HRV features can potentially be used for distinguishing a subject's normal mental state from a stressed one [4], [13] & [14]. In all of these past works, although processing is done in both frequency and time domains, few classification algorithms have been explored for classifying normal from stressed RRintervals. In this paper we used 30 s intervals from the Electrocardiogram (ECG) time series collected during normal and stressed conditions, produced by means of a modified version of the Trier social stress test, to compute HRV-driven features and subsequently applied a set of classification algorithms to distinguish stressed from normal conditions. To classify RR-intervals, we explored classification algorithms that are commonly used for medical applications, namely 1) logistic regression (LR) [16] and 2) linear discriminant analysis (LDA) [6]. Classification performance for various levels of stress over the entire test was quantified using precision, accuracy, sensitivity and specificity measures. Results from both classifiers were then compared to find an optimal classifier and HRV features for stress detection. This work, performed under an IRB-approved protocol, not only provides a method for developing models and classifiers based on human data, but also provides a foundation for a stress indicator tool based on HRV. Further, these classification tools will not only benefit many civilian applications for detecting stress, but also security and military applications for screening such as: border patrol, stress detection for deception [3],[17], and wounded-warrior triage [12].

  7. Heart Rate Variability in Men with Erectile dysfunction

    Directory of Open Access Journals (Sweden)

    Ji Yong Lee

    2011-06-01

    Full Text Available Purpose The objective of this study is to investigate alteration of autonomic nervous system (ANS activity in patients suffering from erectile dysfunction (ED by comparing parameters of heart rate variability (HRV between men with ED and healthy subjects. Methods A retrospective review was performed on 40 ED patients (mean age, 46.0±8.49 years without any disease and 180 healthy control people (mean age, 44.4±7.83 years without ED in our institution from June 2008 to July 2010. And electrocardiographic signals were obtained to measure HRV parameters for both patients and controls in a resting state. Results For the time domain analysis, square root of the mean differences between successive RR intervals (RMSSD representing parasympathetic activity was lower in patients than controls although P-value was not statistically significant (P=0.060. For the frequency domain analysis, high frequency (HF representing parasympathetic activity was lower in patients than controls (P=0.232 and low frequency (LF representing mainly sympathetic activity was higher in patients than controls (P=0.416. Lastly, LF/HF ratio reflecting sympathetic/parasympathetic activity ratio was statistically higher in patients than controls (P=0.027. Conclusions Patients with ED exhibited different HRV parameters compared with normal controls. This suggests that the patients with ED may have some kind of imbalance in the ANS and it may be possible that general imbalance of the ANS is one of the causes of ED. Thus, HRV analysis may give valuable diagnostic information and serve as a rapid screening tool to evaluate altered ANS activity in patients with ED.

  8. HEART RATE RECOVERY AFTER EXERCISE AND NEURAL REGULATION OF HEART RATE VARIABILITY IN 30-40 YEAR OLD FEMALE MARATHON RUNNERS

    Directory of Open Access Journals (Sweden)

    Toshio Matsuoka

    2005-03-01

    Full Text Available The aim of the present study was to examine the effects of endurance training on heart rate (HR recovery after exercise and cardiac autonomic nervous system (ANS modulation in female marathon runners by comparing with untrained controls. Six female marathon runners (M group aged 32-40 years and eight age-matched untrained females (C group performed a maximum-effort treadmill running exercise. Maximal oxygen uptake (VO2max was measured during the exercise with a gas analyzer connected to subjects through a face mask. Heart rate, blood pressure and blood lactate were measured before and after the exercise. Rating of perceived exertion (RPE to the exercise was obtained immediately after the exercise. Holter ECG was recorded and analyzed with power spectral analysis of heart rate variability (HRV to investigate the cardiac ANS modulation. The M group had significantly higher VO2max, faster HR recovery after exercise, higher Mean RR, SDRR, HF power and lower LF/HF ratio at rest compared with the C group. The M group also presented greater percent decrease of blood pressure after exercise, although their blood pressure after exercise was higher than the C group. It is suggested that endurance training induced significant alterations in cardiac ANS modulation at rest and significant acceleration of HR recovery after exercise in female marathon runners. Faster HR recovery after exercise in the female marathon runners should result from their higher levels of HRV, higher aerobic capacity and exaggerated blood pressure response to exercise compared with untrained controls.

  9. Increased heart rate variability in mice overexpressing the Cu/Zn superoxide dismutase.

    Science.gov (United States)

    Thireau, Jérôme; Poisson, Denise; Zhang, Bei Li; Gillet, Ludovic; Le Pécheur, Marie; Andres, Christian; London, Jacqueline; Babuty, Dominique

    2008-08-15

    Cu/Zn superoxide dismutase (SOD1) is implicated in various pathological conditions including Down's syndrome, neurodegenerative diseases, and afflictions of the autonomic nervous system (ANS). To assess the SOD1 contribution to ANS dysfunction, especially its influence on cardiac regulation, we studied the heart rate variability (HRV) and cardiac arrhythmias in conscious 12-month-old male and female transgenic mice for the human SOD1 gene (TghSOD1). TghSOD1 mice presented heart rate reduction as compared with control FVB/N individuals. All HRV parameters reflecting parasympathetic activity were increased in TghSOD1. Pharmacological studies confirmed that the parasympathetic tone was exacerbated and the sympathetic pathway was functional in TghSOD1 mice. A high frequency of atrioventricular block and premature ventricular contractions was observed in TghSOD1. By biochemical assays we found that SOD1 activities were multiplied by 9 and 4 respectively in the heart and brainstem of transgenic mice. A twofold decrease in cholinesterase activity was observed in the heart but not in the brainstem. We demonstrate that SOD1 overexpression induces an ANS dysfunction by an exacerbated vagal tone that may be related to impaired cardiac activity of the cholinesterases and may explain the high occurrence of arrhythmias.

  10. Can illness perceptions predict lower heart rate variability following acute myocardial infarction?

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    Mary Princip

    2016-11-01

    Full Text Available Objective: Decreased heart rate variability (HRV has been reported to be a predictor of mortality after myocardial infarction (MI. Patients’ beliefs and perceptions concerning their illness may play a role in decreased HRV. This study investigated if illness perceptions predict HRV at three months following acute MI. Methods: 130 patients referred to a tertiary cardiology centre, were examined within 48 hours and three months following acute MI. At admission, patients’ cognitive representations of their MI were assessed using the German version of the self-rated Brief Illness Perception Questionnaire (Brief IPQ. At admission and after three months (follow-up, frequency and time domain measures of HRV were obtained from 5-min electrocardiogram (ECG recordings during stable supine resting. Results: Linear hierarchical regression showed that the Brief IPQ dimensions timeline (β coefficient = -0.29; p = .044, personal control (β = 0.47; p = .008 and illness understanding (β = 0.43; p = .014 were significant predictors of HRV, adjusted for age, gender, baseline HRV, diabetes, beta-blockers, left ventricular ejection fraction (LVEF, attendance of cardiac rehabilitation, and depressive symptoms. Conclusions: As patients’ negative perceptions of their illness are associated with lower HRV following acute MI, a brief illness perception questionnaire may help to identify patients who might benefit from a specific illness perceptions intervention.

  11. Impact of Pubertal Development and Physical Activity on Heart Rate Variability in Overweight and Obese Children in Taiwan

    Science.gov (United States)

    Chen, Su-Ru; Chiu, Hung-Wen; Lee, Yann-Jinn; Sheen, Tzong-Chi; Jeng, Chii

    2012-01-01

    Child obesity is frequently associated with dysfunction of autonomic nervous system. Children in pubertal development were suggested to be vulnerable to autonomic nervous system problems such as decrease of heart rate variability from dysregulation of metabolic control. This study explored the influence of pubertal development on autonomic nervous…

  12. Sex and family history of cardiovascular disease influence heart rate variability during stress among healthy adults.

    Science.gov (United States)

    Emery, Charles F; Stoney, Catherine M; Thayer, Julian F; Williams, DeWayne; Bodine, Andrew

    2018-07-01

    Studies of sex differences in heart rate variability (HRV) typically have not accounted for the influence of family history (FH) of cardiovascular disease (CVD). This study evaluated sex differences in HRV response to speech stress among men and women (age range 30-49 years) with and without a documented FH of CVD. Participants were 77 adults (mean age = 39.8 ± 6.2 years; range: 30-49 years; 52% female) with positive FH (FH+, n = 32) and negative FH (FH-, n = 45) of CVD, verified with relatives of participants. Cardiac activity for all participants was recorded via electrocardiogram during a standardized speech stress task with three phases: 5-minute rest, 5-minute speech, and 5-minute recovery. Outcomes included time domain and frequency domain indicators of HRV and heart rate (HR) at rest and during stress. Data were analyzed with repeated measures analysis of variance, with sex and FH as between subject variables and time/phase as a within subject variable. Women exhibited higher HR than did men and greater HR reactivity in response to the speech stress. However, women also exhibited greater HRV in both the time and frequency domains. FH+ women generally exhibited elevated HRV, despite the elevated risk of CVD associated with FH+. Although women participants exhibited higher HR at rest and during stress, women (both FH+ and FH-) also exhibited elevated HRV reactivity, reflecting greater autonomic control. Thus, enhanced autonomic function observed in prior studies of HRV among women is also evident among FH+ women during a standardized stress task. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. Reliability of Heart Rate Variability in Children: Influence of Sex and Body Position During Data Collection.

    Science.gov (United States)

    Silva, Carla Cristiane; Bertollo, Maurizio; Reichert, Felipe Fossati; Boullosa, Daniel Alexandre; Nakamura, Fábio Yuzo

    2017-05-01

    To examine which body position and indices present better reliability of heart rate variability (HRV) measures in children and to compare the HRV analyzed in different body positions between sexes. Twenty eutrophic prepubertal children of each sex participated in the study. The RR intervals were recorded using a portable heart rate monitor twice a day for 7 min in the supine, sitting, and standing positions. The reproducibility was analyzed using the intraclass correlation coefficient (ICC; two way mixed) and within-subject coefficient of variation (CV).Two-way ANOVA with repeated measures was used to compare the sexes. High levels of reproducibility were indicated by higher ICC in the root-mean-square difference of successive normal RR intervals (RMSSD: 0.93 and 0.94) and Poincaré plot of the short-term RR interval variability (SD1: 0.92 and 0.94) parameters for boys and girls, respectively, in the supine position. The ICCs were lower in the sitting and standing positions for all HRV indices. In addition, the girls presented significantly higher values than the boys for SDNN and absolute high frequency (HF; p position. The supine position is the most reproducible for the HRV indices in both sexes, especially the vagal related indices.

  14. Improved detection of congestive heart failure via probabilistic symbolic pattern recognition and heart rate variability metrics.

    Science.gov (United States)

    Mahajan, Ruhi; Viangteeravat, Teeradache; Akbilgic, Oguz

    2017-12-01

    A timely diagnosis of congestive heart failure (CHF) is crucial to evade a life-threatening event. This paper presents a novel probabilistic symbol pattern recognition (PSPR) approach to detect CHF in subjects from their cardiac interbeat (R-R) intervals. PSPR discretizes each continuous R-R interval time series by mapping them onto an eight-symbol alphabet and then models the pattern transition behavior in the symbolic representation of the series. The PSPR-based analysis of the discretized series from 107 subjects (69 normal and 38 CHF subjects) yielded discernible features to distinguish normal subjects and subjects with CHF. In addition to PSPR features, we also extracted features using the time-domain heart rate variability measures such as average and standard deviation of R-R intervals. An ensemble of bagged decision trees was used to classify two groups resulting in a five-fold cross-validation accuracy, specificity, and sensitivity of 98.1%, 100%, and 94.7%, respectively. However, a 20% holdout validation yielded an accuracy, specificity, and sensitivity of 99.5%, 100%, and 98.57%, respectively. Results from this study suggest that features obtained with the combination of PSPR and long-term heart rate variability measures can be used in developing automated CHF diagnosis tools. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Effects of bee venom acupuncture on heart rate variability, pulse wave, and cerebral blood flow for types of Sasang Constitution

    Directory of Open Access Journals (Sweden)

    Lee Sang-min

    2009-03-01

    Full Text Available 1. Objectives: To evaluate effects of bee venom acupuncture on cardiovascular system and differences according to each constitution. 2. Methods: Heart rate variability, pulse wave and the velocity of cerebral blood flow were measured before bee venom acupuncture(BVA, right after and after 30 minuets, had been applied to 20 subjects. 3. Results: 1. BVA did not have effects on measurement variables of heart rate variability. 2. BVA had effects on pulse wave, showing total time, radial augmentation index up and height of percussion wave, time to percussion wave, sum of pulse pressure down. 3. BVA did not have effects on the cerebral blood flow velocity when considering not Sasang Constitution 4. Considering Sasang Constitution, BVA demonstrates different responses in time to preincisura wave, mean blood flow velocity, peak systolic velocity and end diastolic velocity. 4.Conclusion: From those results, the following conclusions are obtained. Cause BVA alters pulse wave and makes differences in the cerebral blood flow velocity according to Sasang Constitution. Various methods of BVA treatment are needed considering Sasang Constitution.

  16. Nonlinear Conte-Zbilut-Federici (CZF Method of Computing LF/HF Ratio: A More Reliable Index of Changes in Heart Rate Variability

    Directory of Open Access Journals (Sweden)

    Vernon Bond Jr

    2016-09-01

    Full Text Available Objectives: Acupuncture treatments are safe and effective for a wide variety of diseases involving autonomic dysregulation. Heart rate variability (HRV is a noninvasive method for assessing sympathovagal balance. The low frequency/high frequency (LF/HF spectral power ratio is an index of sympathovagal influence on heart rate and of cardi

  17. Length and GC content variability of introns among teleostean genomes in the light of the metabolic rate hypothesis.

    Science.gov (United States)

    Chaurasia, Ankita; Tarallo, Andrea; Bernà, Luisa; Yagi, Mitsuharu; Agnisola, Claudio; D'Onofrio, Giuseppe

    2014-01-01

    A comparative analysis of five teleostean genomes, namely zebrafish, medaka, three-spine stickleback, fugu and pufferfish was performed with the aim to highlight the nature of the forces driving both length and base composition of introns (i.e., bpi and GCi). An inter-genome approach using orthologous intronic sequences was carried out, analyzing independently both variables in pairwise comparisons. An average length shortening of introns was observed at increasing average GCi values. The result was not affected by masking transposable and repetitive elements harbored in the intronic sequences. The routine metabolic rate (mass specific temperature-corrected using the Boltzmann's factor) was measured for each species. A significant correlation held between average differences of metabolic rate, length and GC content, while environmental temperature of fish habitat was not correlated with bpi and GCi. Analyzing the concomitant effect of both variables, i.e., bpi and GCi, at increasing genomic GC content, a decrease of bpi and an increase of GCi was observed for the significant majority of the intronic sequences (from ∼ 40% to ∼ 90%, in each pairwise comparison). The opposite event, concomitant increase of bpi and decrease of GCi, was counter selected (from hypothesis that the metabolic rate plays a key role in shaping genome architecture and evolution of vertebrate genomes.

  18. Classic electrocardiogram-based and mobile technology derived approaches to heart rate variability are not equivalent.

    Science.gov (United States)

    Guzik, Przemyslaw; Piekos, Caroline; Pierog, Olivia; Fenech, Naiman; Krauze, Tomasz; Piskorski, Jaroslaw; Wykretowicz, Andrzej

    2018-05-01

    We compared classic ECG-derived versus a mobile approach to heart rate variability (HRV) measurement. 29 young adult healthy volunteers underwent a simultaneous recording of heart rate using an ECG and a chest heart rate monitor at supine rest, during mental stress and active standing. Mean RR interval, Standard Deviation of Normal-to-Normal (SDNN) of RR intervals, and Root Mean Square of the Successive Differences (RMSSD) between RR intervals were computed in 168 pairs of 5-minute epochs by in-house software on a PC (only sinus beats) and by mobile application "ELITEHRV" on a smartphone (no beat type identification). ECG analysis showed that 33.9% of the recordings contained at least one non-sinus beat or artefact, the mobile app did not report this. The mean RR intervals were significantly longer (p = 0.0378), while SDNN (p = 0.0001) and RMSSD (p = 0.0199) were smaller for the mobile approach. Measures of identical HRV parameters by ECG-based and mobile approaches are not equivalent. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. A Prospective Comparison Study of Heart Rate Variability During Menses in Young Women With Dysmenorrhea.

    Science.gov (United States)

    Wang, Yu-Jen; Wang, Yi-Zen; Yeh, Mei-Ling

    2016-07-01

    Numerous studies have demonstrated autonomic abnormalities in various pain conditions. However, few have investigated heart rate variability (HRV) in young women with primary dysmenorrhea, and the conclusions have been inconsistent. More evidence is required to confirm the reported trend for consistent fluctuation of HRV parameters in dysmenorrhea. The study's aim was to determine whether significant differences exist between young women with and without dysmenorrhea for heart rate (HR), blood pressure (BP), and HRV parameters during menses. A prospective comparison design with repeated measures was used. Sixty-six women aged 18-25 with dysmenorrhea and 54 eumenorrheic women were recruited from a university in northern Taiwan. High-frequency and low-frequency HRV parameters (HF and LF), LF/HF ratio, BP, and HR were measured daily between 8 p.m. and 10 p.m. from Day 1 to Day 6 during menses. The generalized estimating equation was used to analyze the effects of group, time, and Group × Time interaction on these variables. HF values were significantly lower in the dysmenorrhea than in the eumenorrhea group, but there were no differences in BP, HR, LF, or LF/HF ratio. Reduced HF values reflect reduced parasympathetic activity and autonomic instability in young women with dysmenorrhea. Future longitudinal studies are warranted to examine autonomic regulation in menstrual pain of varying intensities associated with dysmenorrhea-related symptoms and to clarify the causal relationship between dysmenorrhea and HRV fluctuations. © The Author(s) 2016.

  20. Low heart rate variability in patients with clinical burnout.

    Science.gov (United States)

    Lennartsson, Anna-Karin; Jonsdottir, Ingibjörg; Sjörs, Anna

    2016-12-01

    Several studies have shown that acute psychosocial stress and chronic psychosocial stress reduce heart rate variability (HRV). It is likely that individuals suffering from burnout have reduced HRV, as a consequence of the long-term stress exposure. This study investigated HRV in 54 patients with clinical burnout (40 women and 14 men) and in 55 individuals reporting low burnout scores (healthy; 24 women and 31 men) and 52 individuals reporting high burnout scores (non-clinical burnout; 33 women and 19 men). The participants underwent a 300s ECG recording in the supine position. Standard deviation of normal R-R intervals (SDNN) and the root mean square of successive normal interval differences (RMSSD) were derived from time domain HRV analysis. Frequency domain HRV measures; total power (TP), low frequency power (LF), high frequency power (HF), and LF/HF ratio were calculated. All HRV measures, except LF/HF ratio, were lower in the clinical burnout patients compared to both the non-clinical burnout group and the healthy group. The difference was larger between the patients and the healthy group than between the patients and the non-clinical burnout group. HRV did not differ significantly between the non-clinical burnout group and the healthy group. Low HRV in burnout patients may constitute one of the links to associated adverse health, since low HRV reflects low parasympathetic activity - and accordingly low anabolic/regenerative activity. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Heart Rate Variability and Autonomic Modulations in Preeclampsia.

    Directory of Open Access Journals (Sweden)

    Shaza M Musa

    Full Text Available Although the exact pathophysiology of preeclampsia is not well understood, autonomic nervous system imbalance is suggested as one of the main factors.To investigate heart rate variability (HRV and autonomic modulations in Sudanese pregnant women with preeclampsia.A case-control study (60 women in each arm was conducted at Omdurman Maternity Hospital-Sudan, during the period from June to August, 2014. Cases were women presented with preeclampsia and healthy pregnant women were the controls. Studied groups were matched for important determinants of HRV. Natural logarithm (Ln of total power (TP, high frequency (HF, low frequency (LF and very low frequency (VLF were used to determine HRV. Normalized low and high frequencies (LF Norm and HF Norm were used to evaluate sympathetic and parasympathetic autonomic modulations respectively.Patients with preeclampsia achieved significantly higher LF Norm [49.80 (16.25 vs. 44.55 (19.15, P = 0.044] and LnLF/HF [0.04 (0.68 vs. -0.28 (0.91, P = 0.023] readings, but lower HF Norm [49.08 (15.29 vs. 55.87 (19.56, P = 0.012], compared with healthy pregnant women. Although all other HRV measurements were higher in the patients with preeclampsia compared with the controls, only LnVLF [4.50 (1.19 vs. 4.01 (1.06, P = 0.017] and LnLF [4.01 (1.58 vs. 3.49 (1.23, P = 0.040] reached statistical significance.The study adds further evidence for the dominant cardiac sympathetic modulations on patients with preeclampsia, probably secondary to parasympathetic withdrawal in this group. However, the higher LnVLF and LnLF readings achieved by preeclamptic women compared with the controls are unexpected in the view that augmented sympathetic modulations usually depresses all HRV parameters including these two measures.

  2. Intelligent control for large-scale variable speed variable pitch wind turbines

    Institute of Scientific and Technical Information of China (English)

    Xinfang ZHANG; Daping XU; Yibing LIU

    2004-01-01

    Large-scale wind turbine generator systems have strong nonlinear multivariable characteristics with many uncertain factors and disturbances.Automatic control is crucial for the efficiency and reliability of wind turbines.On the basis of simplified and proper model of variable speed variable pitch wind turbines,the effective wind speed is estimated using extended Kalman filter.Intelligent control schemes proposed in the paper include two loops which operate in synchronism with each other.At below-rated wind speed,the inner loop adopts adaptive fuzzy control based on variable universe for generator torque regulation to realize maximum wind energy capture.At above-rated wind speed, a controller based on least square support vector machine is proposed to adjust pitch angle and keep rated output power.The simulation shows the effectiveness of the intelligent control.

  3. How do males of Hypsiboas goianus (Hylidae: Anura respond to conspecific acoustic stimuli?

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    Alessandro R. Morais

    2015-12-01

    Full Text Available ABSTRACT Acoustic communication plays an important role in the social behavior of anurans. Acoustic signals, which can be used in different contexts such as mate attraction and territory defense, may mediate social interactions among individuals. Herein, we used playback experiments to test whether males of Hypsiboas goianus (Lutz, 1968 change their vocal behavior in response to conspecific advertisement calls. Specifically, we used different field playback experiments in which we modified the time interval between advertisement calls to simulate males with distinct states of motivation (Sequence A and B. We did not observe differences in the acoustic response of males of H. goianus between the two types of field playback experiments. On the other hand, we observed that H. goianus males reduce the dominant frequency of the advertisement call and increase the rate of aggressive calls in response to a conspecific competitor. Our results suggest that the acoustic plasticity observed in males of H. goianus represents an aggressive response that allows repelling conspecific individuals.

  4. Precompetitive assessment of heart rate variability in elite female athletes during play offs.

    Science.gov (United States)

    D'Ascenzi, Flavio; Alvino, Federico; Natali, Benedetta M; Cameli, Matteo; Palmitesta, Paola; Boschetti, Giampaolo; Bonifazi, Marco; Mondillo, Sergio

    2014-05-01

    Heart rate variability (HRV) has been rarely applied in elite athletes prior to competition. The aim of this study was to examine the changes in HRV in elite female volleyball players before a stressful match during play offs and to evaluate the impact on sport-specific performance. A short-term resting HRV analysis was applied right after the night sleep in ten female athletes 1 and 2 days prior to the match and the day of the competition. Approaching the decisive match, RR interval, resting heart rate (HR), pNN50, rMSDD and SD1 did not significantly vary. SD2 significantly increased in comparison with first-day measurement (Psports exhibit a slight change in HRV prior to a decisive competition, without a pronounced variation of the autonomic nervous system activity. A day-to-day HRV measurement could be a useful tool to evaluate the impact of a competition on the autonomic nervous system in athletes, also considering the relationship between sympathetic activity and athletic performance. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  5. Pre-performance Physiological State: Heart Rate Variability as a Predictor of Shooting Performance.

    Science.gov (United States)

    Ortega, E; Wang, C J K

    2018-03-01

    Heart rate variability (HRV) is commonly used in sport science for monitoring the physiology of athletes but not as an indicator of physiological state from a psychological perspective. Since HRV is established to be an indicator of emotional responding, it could be an objective means of quantifying an athlete's subjective physiological state before competition. A total of 61 sport shooters participated in this study, of which 21 were novice shooters, 19 were intermediate shooters, and 21 were advanced level shooters. HRV, self-efficacy, and use of mental skills were assessed before they completed a standard shooting performance task of 40 shots, as in a competition qualifying round. The results showed that HRV was significantly positively correlated with self-efficacy and performance and was a significant predictor of shooting performance. In addition, advanced shooters were found to have significantly lower average heart rate before shooting and used more self-talk, relaxation, imagery, and automaticity compared to novice and intermediate shooters. HRV was found to be useful in identifying the physiological state of an athlete before competing, and as such, coaches and athletes can adopt practical strategies to improve the pre-performance physiological state as a means to optimize performance.

  6. Social psychological variables in populations contrasted by income and suicide rate: Durkheim revisited.

    Science.gov (United States)

    Ferrada-Noli, M

    1997-08-01

    The ten richest and ten poorest municipalities of Sweden were investigated with respect to national statistics to assess the relationship between suicide incidence, discrete social psychological variables associated with welfare admittance among the elderly, and income of municipality. The relative frequency of suicide was 1.6 times greater for Swedes from the low-income municipalities than for those from the high-income ones. The group of municipalities with the highest suicide rate had a significantly higher proportion of older people in need of municipal social assistance at their homes and also a significantly higher proportion of elderly living in municipality-managed 'service-homes.' The findings replicate earlier investigations and suggest social psychological indicators denoting less favourable economic and social resources are also associated with both an increased suicide rate and a decreased county or municipal income. Some theoretical issues of the socioeconomic and of the external restraint hypotheses of the incidence of suicide, contradicted by the present findings as well as of Durkheim's hypothesis of social control are discussed. Further, we suggest the consideration of negative socioeconomic conditions as a risk factor amid psychiatric clinical assessments of risk for suicidal behaviour.

  7. Higher resting heart rate variability predicts skill in expressing some emotions.

    Science.gov (United States)

    Tuck, Natalie L; Grant, Rosemary C I; Sollers, John J; Booth, Roger J; Consedine, Nathan S

    2016-12-01

    Vagally mediated heart rate variability (vmHRV) is a measure of cardiac vagal tone, and is widely viewed as a physiological index of the capacity to regulate emotions. However, studies have not directly tested whether vmHRV is associated with the ability to facially express emotions. In extending prior work, the current report tested links between resting vmHRV and the objectively assessed ability to facially express emotions, hypothesizing that higher vmHRV would predict greater expressive skill. Eighty healthy women completed self-reported measures, before attending a laboratory session in which vmHRV and the ability to express six emotions in the face were assessed. A repeated measures analysis of variance revealed a marginal main effect for vmHRV on skill overall; individuals with higher resting vmHRV were only better able to deliberately facially express anger and interest. Findings suggest that differences in resting vmHRV are associated with the objectively assessed ability to facially express some, but not all, emotions, with potential implications for health and well-being. © 2016 Society for Psychophysiological Research.

  8. Discrepancies between self and observer ratings of depression. The relationship to demographic, clinical and personality variables.

    Science.gov (United States)

    Enns, M W; Larsen, D K; Cox, B J

    2000-10-01

    The observer-rated Hamilton depression scale (HamD) and the self-report Beck Depression Inventory (BDI) are among the most commonly used rating scales for depression, and both have well demonstrated reliability and validity. However, many depressed subjects have discrepant scores on these two assessment methods. The present study evaluated the ability of demographic, clinical and personality factors to account for the discrepancies observed between BDI and HamD ratings. The study group consisted of 94 SCID-diagnosed outpatients with a current major depressive disorder. Subjects were rated with the 21-item HamD and completed the BDI and the NEO-Five Factor Inventory. Younger age, higher educational attainment, and depressive subtype (atypical, non-melancholic) were predictive of higher BDI scores relative to HamD observer ratings. In addition, high neuroticism, low extraversion and low agreeableness were associated with higher endorsement of depressive symptoms on the BDI relative to the HamD. In general, these predictive variables showed a greater ability to explain discrepancies between self and observer ratings of psychological symptoms of depression compared to somatic symptoms of depression. The study does not determine which aspects of neuroticism and extraversion contribute to the observed BDI/HamD discrepancies. Depression ratings obtained with the BDI and HamD are frequently discordant and a number of patient characteristics robustly predict the discrepancy between these two rating methods. The value of multi-modal assessment in the conduct of research on depressive disorders is re-affirmed.

  9. Changes of heart rate variability and prefrontal oxygenation during Tai Chi practice versus arm ergometer cycling

    OpenAIRE

    Lu, Xi; Hui-Chan, Christina Wan-Ying; Tsang, William Wai-Nam

    2016-01-01

    [Purpose] Exercise has been shown to improve cardiovascular fitness and cognitive function. Whether the inclusion of mind over exercise would increase parasympathetic control of the heart and brain activities more than general exercise at a similar intensity is not known. The aim of this study was to compare the effects of Tai Chi (mind-body exercise) versus arm ergometer cycling (body-focused exercise) on the heart rate variability and prefrontal oxygenation level. [Subjects and Methods] A T...

  10. Omega-3 Fatty Acid Supplementation Improves Heart Rate Variability in Obese Children

    Directory of Open Access Journals (Sweden)

    Christoph Baumann

    2018-01-01

    Full Text Available Obese children and adolescents are at high risk of developing cardiovascular diseases later in life. We hypothesized that cardiovascular prophylaxis with omega-3 fatty acids could benefit them. In our study, 20 children and adolescents (mean body mass index percentile: 99.1; mean age: 11.0 years underwent two ambulatory 24 h Holter electrocardiography (ECG recordings (before and after at least 3 months of omega-3 fatty acid supplementation. Time domain heart rate variability (HRV and heart rate (HR were examined for these patients. As a control, we used 24 h Holter ECG recordings of 94 nonobese children and adolescents. Time domain HRV parameters, which are indicators of vagal stimulation, were significantly lower in obese patients than in healthy controls, but HR was higher (standard deviation of the normal-to-normal [SDNN] interbeat intervals: −34.02%; root mean square of successive differences [RMSSD] between normal heartbeats: −40.66%; percentage of consecutive RR intervals [pNN50]: −60.24%; HR: +13.37%. After omega-3 fatty acid supplementation, time domain HRV parameters and HR of obese patients were similar to the values of healthy controls (SDNN interbeat intervals: −21.73%; RMSSD: −19.56%; pNN50: −25.59%; HR: +3.94%. Therefore, omega-3 fatty acid supplementation may be used for cardiovascular prophylaxis in obese children and adolescents.

  11. Hypersonic Boundary Layer Measurements with Variable Blowing Rates Using Molecular Tagging Velocimetry

    Science.gov (United States)

    Bathel, Brett F.; Danehy, Paul M.; Johansen, Craig T.; Jones, Stephen B.; Goyne, Christopher P.

    2012-01-01

    Measurements of mean and instantaneous streamwise velocity profiles in a hypersonic boundary layer with variable rates of mass injection (blowing) of nitrogen dioxide (NO2) were obtained over a 10-degree half-angle wedge model. The NO2 was seeded into the flow from a slot located 29.4 mm downstream of the sharp leading edge. The top surface of the wedge was oriented at a 20 degree angle in the Mach 10 flow, yielding an edge Mach number of approximately 4.2. The streamwise velocity profiles and streamwise fluctuating velocity component profiles were obtained using a three-laser NO2->NO photolysis molecular tagging velocimetry method. Observed trends in the mean streamwise velocity profiles and profiles of the fluctuating component of streamwise velocity as functions of the blowing rate are described. An effort is made to distinguish between the effect of blowing rate and wall temperature on the measured profiles. An analysis of the mean velocity profiles for a constant blowing rate is presented to determine the uncertainty in the measurement for different probe laser delay settings. Measurements of streamwise velocity were made to within approximately 120 gm of the model surface. The streamwise spatial resolution in this experiment ranged from 0.6 mm to 2.6 mm. An improvement in the spatial precision of the measurement technique has been made, with spatial uncertainties reduced by about a factor of 2 compared to previous measurements. For the quiescent flow calibration measurements presented, uncertainties as low as 2 m/s are obtained at 95% confidence for long delay times (25 gs). For the velocity measurements obtained with the wind tunnel operating, average single-shot uncertainties of less than 44 m/s are obtained at 95% confidence with a probe laser delay setting of 1 gs. The measurements were performed in the 31-inch Mach 10 Air Tunnel at the NASA Langley Research Center.

  12. Heart rate variability recovery after a skyrunning marathon and correlates of performance

    Directory of Open Access Journals (Sweden)

    Michaela Mertová

    2017-12-01

    Full Text Available Background: It is well known that vigorous physical activity induces functional changes in cardiac autonomic nervous system (ANS activity that is sustained several hours after exercise. However, data related to ANS recovery after more extreme endurance events, such as skyrunning marathons, are still lacking. Objective: The aims of this prospective cohort study were firstly, to determine the ANS response to a SkyMarathon, and secondly, to examine correlates of run performance. Methods: Ten male skyrunners aged 37.2 ± 9.2 years were recruited. The race was performed at a mean intensity 85.4 ± 3.7% of heart rate reserve, and lasted for 338 ± 38 min. Morning supine heart rate variability was measured at 10, 2 and 1 days before race, on the race day, at 5 min intervals for 30 min immediately post-race and then at 5 h and 30 h post. High-frequency power (HF, 0.15-0.50 Hz, low-frequency power (LF, 0.05-0.15 Hz, and square root of the mean of the squares of the successive differences (RMSSD were calculated and transformed by natural logarithm (Ln. Results: Sympathovagal balance (Ln LF/HF was most likely increased above baseline during the 30 min post-race and returned to baseline by 5 h. Vagal activity (Ln RMSSD and Ln HF was most likely decreased below baseline during the 30 min post-race and 5 h of post-race, and recovered to baseline by 30 h. Race time correlated with resting heart rate (r = .81, body mass index (r = .73, maximal power output (r = -.70, and maximal oxygen uptake (r = -.61. Conclusions: The SkyMarathon elicited disturbances in ANS activity, with relative sympathetic activity increased up to 5 h post-race and vagal activity recovering by 30 h. Resting heart rate, body mass index, maximal power output, and maximal oxygen uptake were associated with SkyMarathon performance prediction.

  13. Dynamics of heart rate variability analysed through nonlinear and linear dynamics is already impaired in young type 1 diabetic subjects.

    Science.gov (United States)

    Souza, Naiara M; Giacon, Thais R; Pacagnelli, Francis L; Barbosa, Marianne P C R; Valenti, Vitor E; Vanderlei, Luiz C M

    2016-10-01

    Autonomic diabetic neuropathy is one of the most common complications of type 1 diabetes mellitus, and studies using heart rate variability to investigate these individuals have shown inconclusive results regarding autonomic nervous system activation. Aims To investigate the dynamics of heart rate in young subjects with type 1 diabetes mellitus through nonlinear and linear methods of heart rate variability. We evaluated 20 subjects with type 1 diabetes mellitus and 23 healthy control subjects. We obtained the following nonlinear indices from the recurrence plot: recurrence rate (REC), determinism (DET), and Shanon entropy (ES), and we analysed indices in the frequency (LF and HF in ms2 and normalised units - nu - and LF/HF ratio) and time domains (SDNN and RMSSD), through analysis of 1000 R-R intervals, captured by a heart rate monitor. There were reduced values (p<0.05) for individuals with type 1 diabetes mellitus compared with healthy subjects in the following indices: DET, REC, ES, RMSSD, SDNN, LF (ms2), and HF (ms2). In relation to the recurrence plot, subjects with type 1 diabetes mellitus demonstrated lower recurrence and greater variation in their plot, inter-group and intra-group, respectively. Young subjects with type 1 diabetes mellitus have autonomic nervous system behaviour that tends to randomness compared with healthy young subjects. Moreover, this behaviour is related to reduced sympathetic and parasympathetic activity of the autonomic nervous system.

  14. Analysis of acoustic cardiac signals for heart rate variability and murmur detection using nonnegative matrix factorization-based hierarchical decomposition

    DEFF Research Database (Denmark)

    Shah, Ghafoor; Koch, Peter; Papadias, Constantinos B.

    2014-01-01

    The detection of heart rate variability (HRV) via cardiac auscultation examination can be a useful and inexpensive tool which, however, is challenging in the presence of pathological signals and murmurs. The aim of this research is to analyze acoustic cardiac signals for HRV and murmur detection...

  15. 256-slice CT coronary angiography in atrial fibrillation: The impact of mean heart rate and heart rate variability on image quality

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Liang-Kuang [Department of Radiology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan (China); College of Medicine, Fu Jen Catholic University, Taipei, Taiwan (China); Hsu, Shih-Ming [Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan (China); Mok, Greta S.P. [Department of Electrical and Electronics Engineering, Faculty of Science and Technology, University of Macau, Macau (China); Law, Wei-Yip; Lu, Kun-Mu [Department of Radiology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan (China); Yang, Ching-Ching, E-mail: g39220003@yahoo.com.tw [Department of Radiological Technology, Tzu Chi College of Technology, 880, Sec.2, Chien-kuo Rd. Hualien 970, Taiwan (China); Wu, Tung-Hsin, E-mail: tung@ym.edu.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, 155 Li-Nong St., Sec. 2, Taipei 112, Taiwan (China)

    2011-08-21

    Objective: The aim of this study was to evaluate the image quality of 256-MDCT in atrial fibrillation and to compare the findings with those among patients in sinus rhythm. Materials: All reconstructed images were evaluated by two independent experienced readers blinded to patient information, heart rate, and ECG results to assess the diagnostic quality of images of the coronary artery segments using axial images, multi-planar reformations, maximum intensity projections, and volume rendering technique. Results: No statistical significance was detected in terms of the overall image quality between patients in sinus rhythm and with atrial fibrillation. Pearson's correlation analysis showed no significant association between image quality and mean heart rate no matter for patients in sinus rhythm or with atrial fibrillation. Similarly, there was no correlation between image quality and heart rate variability for either patients in sinus rhythm or with atrial fibrillation. Our results showed that the optimal reconstruction window depends on patient's HR, and the pattern for patients in atrial fibrillation is similar to that obtained from non-atrial fibrillation patients. Conclusion: This study shows the potential of using 256-MDCT coronary angiography in patients with atrial fibrillation. Our results suggest that when appropriate reconstruction timing window is applied, patients with atrial fibrillation do not have to be excluded from MDCT coronary angiographic examinations.

  16. 256-slice CT coronary angiography in atrial fibrillation: The impact of mean heart rate and heart rate variability on image quality

    International Nuclear Information System (INIS)

    Chen, Liang-Kuang; Hsu, Shih-Ming; Mok, Greta S.P.; Law, Wei-Yip; Lu, Kun-Mu; Yang, Ching-Ching; Wu, Tung-Hsin

    2011-01-01

    Objective: The aim of this study was to evaluate the image quality of 256-MDCT in atrial fibrillation and to compare the findings with those among patients in sinus rhythm. Materials: All reconstructed images were evaluated by two independent experienced readers blinded to patient information, heart rate, and ECG results to assess the diagnostic quality of images of the coronary artery segments using axial images, multi-planar reformations, maximum intensity projections, and volume rendering technique. Results: No statistical significance was detected in terms of the overall image quality between patients in sinus rhythm and with atrial fibrillation. Pearson's correlation analysis showed no significant association between image quality and mean heart rate no matter for patients in sinus rhythm or with atrial fibrillation. Similarly, there was no correlation between image quality and heart rate variability for either patients in sinus rhythm or with atrial fibrillation. Our results showed that the optimal reconstruction window depends on patient's HR, and the pattern for patients in atrial fibrillation is similar to that obtained from non-atrial fibrillation patients. Conclusion: This study shows the potential of using 256-MDCT coronary angiography in patients with atrial fibrillation. Our results suggest that when appropriate reconstruction timing window is applied, patients with atrial fibrillation do not have to be excluded from MDCT coronary angiographic examinations.

  17. Spatial and temporal variability in sedimentation rates associated with cutoff channel infill deposits: Ain River, France

    Science.gov (United States)

    Piégay, H.; Hupp, C.R.; Citterio, A.; Dufour, S.; Moulin, B.; Walling, D.E.

    2008-01-01

    Floodplain development is associated with lateral accretion along stable channel geometry. Along shifting rivers, the floodplain sedimentation is more complex because of changes in channel position but also cutoff channel presence, which exhibit specific overflow patterns. In this contribution, the spatial and temporal variability of sedimentation rates in cutoff channel infill deposits is related to channel changes of a shifting gravel bed river (Ain River, France). The sedimentation rates estimated from dendrogeomorphic analysis are compared between and within 14 cutoff channel infills. Detailed analyses along a single channel infill are performed to assess changes in the sedimentation rates through time by analyzing activity profiles of the fallout radionuclides 137Cs and unsupported 210Pb. Sedimentation rates are also compared within the channel infills with rates in other plots located in the adjacent floodplain. Sedimentation rates range between 0.65 and 2.4 cm a−1 over a period of 10 to 40 years. The data provide additional information on the role of distance from the bank, overbank flow frequency, and channel geometry in controlling the sedimentation rate. Channel infills, lower than adjacent floodplains, exhibit higher sedimentation rates and convey overbank sediment farther away within the floodplain. Additionally, channel degradation, aggradation, and bank erosion, which reduce or increase the distance between the main channel and the cutoff channel aquatic zone, affect local overbank flow magnitude and frequency and therefore sedimentation rates, thereby creating a complex mosaic of sedimentation zones within the floodplain and along the cutoff channel infills. Last, the dendrogeomorphic and 137Cs approaches are cross validated for estimating the sedimentation rate within a channel infill.

  18. Length and GC content variability of introns among teleostean genomes in the light of the metabolic rate hypothesis.

    Directory of Open Access Journals (Sweden)

    Ankita Chaurasia

    Full Text Available A comparative analysis of five teleostean genomes, namely zebrafish, medaka, three-spine stickleback, fugu and pufferfish was performed with the aim to highlight the nature of the forces driving both length and base composition of introns (i.e., bpi and GCi. An inter-genome approach using orthologous intronic sequences was carried out, analyzing independently both variables in pairwise comparisons. An average length shortening of introns was observed at increasing average GCi values. The result was not affected by masking transposable and repetitive elements harbored in the intronic sequences. The routine metabolic rate (mass specific temperature-corrected using the Boltzmann's factor was measured for each species. A significant correlation held between average differences of metabolic rate, length and GC content, while environmental temperature of fish habitat was not correlated with bpi and GCi. Analyzing the concomitant effect of both variables, i.e., bpi and GCi, at increasing genomic GC content, a decrease of bpi and an increase of GCi was observed for the significant majority of the intronic sequences (from ∼ 40% to ∼ 90%, in each pairwise comparison. The opposite event, concomitant increase of bpi and decrease of GCi, was counter selected (from <1% to ∼ 10%, in each pairwise comparison. The results further support the hypothesis that the metabolic rate plays a key role in shaping genome architecture and evolution of vertebrate genomes.

  19. RELATIONSHIP BETWEEN CLIMATE VARIABLES, TRUNK GROWTH RATE AND WOOD DENSITY OF Eucalyptus grandis W. Mill ex Maiden TREES

    Directory of Open Access Journals (Sweden)

    Carlos Roberto Sette Jr

    2016-04-01

    Full Text Available ABSTRACT Climatic conditions stimulates the cambial activity of plants, and cause significant changes in trunk diameter growth and wood characteristics. The objective of this study was to evaluate the influence of climate variables in the diameter growth rate of the stem and the wood density of Eucalyptus grandis trees in different classes of the basal area. A total of 25 Eucalyptus trees at 22 months of age were selected according to the basal area distribution. Dendrometer bands were installed at the height of 1.30 meters (DBH to monitor the diameter growth every 14 days, for 26 months. After measuring growth, the trees were felled and wood discs were removed at the DBH level to determine the radial density profile through x-ray microdensitometry and then re-scale the average values every 14 days. Climatic variables for the monitoring period were obtained and grouped every 14 days. The effect of the climate variables was determined by maximum and minimum growth periods in assessing trunk growth. These growth periods were related with precipitation, average temperature and relative air humidity. The re-scaled wood density values, calculated using the radial growth of the tree trunks measured accurately with steel dendrometers, enabled the determination of the relationship of small changes in wood density and the effect of the climatic variations and growth rate of eucalyptus tree trunks. A high sensitivity of the wood density to variation in precipitation levels was found.

  20. Change in heart rate variability after the adult attachment interview in dissociative patients.

    Science.gov (United States)

    Farina, Benedetto; Speranza, Anna Maria; Imperatori, Claudio; Quintiliani, Maria Isabella; Della Marca, Giacomo

    2015-01-01

    The aim of this study was to assess heart rate variability (HRV) in individuals with dissociative disorders (DD) before and after the Adult Attachment Interview (AAI). Electrocardiograms were recorded before, during, and after the AAI in 13 individuals with DD and 13 healthy participants matched for age and gender. Significant change in HRV was observed only in the DD group. After the AAI, those with DD showed significant increases in the low frequency/high frequency ratio (pre-AAI = 1.91 ± 1.19; post-AAI = 4.03 ± 2.40; Wilcoxon test = -2.76, p = .005). Our results suggest that the retrieval of childhood attachment experiences in individuals with DD is associated with a change in HRV patterns that could reflect the emotion dysregulation of dissociative psychopathological processes.

  1. Heart Rate Variability in Cavalier King Charles Spaniels with Different Degree of Myxomatous Mitral Valve Disease

    DEFF Research Database (Denmark)

    Rasmussen, Caroline Elisabeth; Falk, Bo Torkel; Zois, Nora Elisabeth

    2010-01-01

    Sciences, University of Copenhagen, Frederiksberg, Denmark, 2Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden; and 3Novo Nordic A/S, Maaloev, Denmark. Introduction: Modulation of heart rate by the autonomic nervous system can indirectly be measured by heart rate...... variability (HRV). Reduced HRV is seen in dogs with heart failure secondary to myxomatous mitral valve disease (MMVD). However, HRV is suggested to increase with disease progression in dogs with early stages of MMVD. Comparable results are found in people with primary mitral valve prolapse, a disease...... resembling canine MMVD. Aim: To associate progression of MMVD in dogs with time and frequency domain HRV, analysed from 24-hour electrocardiography. Materials and Methods: Eighty-one Cavalier King Charles Spaniels (CKCS) were examined by echocardiography and 24-hour electrocardiography. CKCS were divided...

  2. C-reactive protein, heart rate variability and prognosis in community subjects with no apparent heart disease

    DEFF Research Database (Denmark)

    Sajadieh, A; Nielsen, OW; Rasmussen, Verner

    2006-01-01

    OBJECTIVES: Increased C-reactive protein (CRP) and reduced heart rate variability (HRV) both indicate poor prognosis. An inverse association between HRV and CRP has been reported, suggesting an interaction between inflammatory and autonomic systems. However, the prognostic impact of this interact...... of four HRV measures were significantly associated with increased rate of death or myocardial infarction. In a Cox model with CRP >or=2.5 microg mL(-1), standard deviation for the mean value of the time between normal complexes...... examinations, and 24-h Holter monitoring. Four time domain measures of HRV were studied. All were prospectively followed for up to 5 years. RESULTS: Mean age was 64 years (55-75). During the follow-up, 46 total deaths and 11 cases of definite acute myocardial infarction were observed. Both CRP and three...

  3. Heat rate variability and dyssomnia and their correlations to neurological defects in cerebral infarction patients complicated by insomnia A concurrent non-randomized case-control study

    Institute of Scientific and Technical Information of China (English)

    Jianping Chu; Xueli Shen; Jun Fan; Changhai Chen; Shuyang Lin

    2008-01-01

    BACKGROUND: Heart rate variability refers to the beat-to-beat alteration in heart rate. It is usually a slight periodic variation of R-R intervals. Much information of autonomic nerve system balance can be obtained by measuring the heart rate variability of patients. It remains to be shown whether heart rate variability can be used as an index for determining the severity of insomnia and cerebral infarction. OBJECTIVE: This study aimed to analyze the correlation for each frequency spectrum parameter of heart rate variability with an insomnia index, as well as the degree of neurological defects in patients with simple cerebral infarction and cerebral infarction complicated by insomnia. The goal was to verify the feasibility of frequency spectrum parameters for heart rate variability as a marker for insomnia and cerebral infarction. DESIGN: A case-control observation. SETTING: Department of Neurology, First Hospital Affiliated to China Medical University. PARTICIPANTS: Sixty inpatients, and/or outpatients, with cerebral infarction were admitted to the 202 Hospital of Chinese PLA between December 2005 and October 2006, confirmed by CT, and recruited to the study. According to the insomnia condition (insomnia is defined by a Pittsburgh Sleep Quality Index score > 7), the patients were assigned to a simple cerebral infarction group and a cerebral infarction complicated by insomnia group, with 30 subjects in each group. Thirty additional subjects, who concurrently received ex-aminations and were confirmed to not suffer from cerebral infarction and insomnia, were recruited into the control group. Written informed consent was obtained from each subject for laboratory specimens. The pro-tocol was approved by the Hospital's Ethics Committee. METHODS: Following admission, each subject's neurological impairment was assessed with the National Institutes of Health Stroke Scale and Pittsburgh Sleep Quality Index. Heart rate variability of each subject was measured with an

  4. Yoga Nidra relaxation increases heart rate variability and is unaffected by a prior bout of Hatha yoga.

    Science.gov (United States)

    Markil, Nina; Whitehurst, Michael; Jacobs, Patrick L; Zoeller, Robert F

    2012-10-01

    The measurement of heart rate variability (HRV) is often applied as an index of autonomic nervous system (ANS) balance and, therefore, myocardial stability. Previous studies have suggested that relaxation or mind-body exercise can influence ANS balance positively as measured by HRV but may act via different mechanisms. No studies, to the authors' knowledge, have examined the acute response in HRV to interventions combining relaxation and mind-body exercise. The objective of this study was to compare the acute HRV responses to Yoga Nidra relaxation alone versus Yoga Nidra relaxation preceded by Hatha yoga. This was a randomized counter-balanced trial. The trial was conducted in a university exercise physiology laboratory. Subjects included 20 women and men (29.15±6.98 years of age, with a range of 18-47 years). Participants completed a yoga plus relaxation (YR) session and a relaxation only (R) session. The YR condition produced significant changes from baseline in heart rate (HR; beats per minute [bpm], pheart rate (bpm, p<0.001) as well as indices of HRV: R-R (ms, p<0.001), HF (ms(2), p=0.004), LF (%, p=0.005), HF (%, p=0.008) and LF:HF ratio (%, p=0.008). There were no significant differences between conditions at baseline nor for the changes from baseline for any of the variables. These changes demonstrate a favorable shift in autonomic balance to the parasympathetic branch of the ANS for both conditions, and that Yoga Nidra relaxation produces favorable changes in measures of HRV whether alone or preceded by a bout of Hatha yoga.

  5. Validity of the Elite HRV Smartphone Application for Examining Heart Rate Variability in a Field-Based Setting.

    Science.gov (United States)

    Perrotta, Andrew S; Jeklin, Andrew T; Hives, Ben A; Meanwell, Leah E; Warburton, Darren E R

    2017-08-01

    Perrotta, AS, Jeklin, AT, Hives, BA, Meanwell, LE, and Warburton, DER. Validity of the elite HRV smartphone application for examining heart rate variability in a field-based setting. J Strength Cond Res 31(8): 2296-2302, 2017-The introduction of smartphone applications has allowed athletes and practitioners to record and store R-R intervals on smartphones for immediate heart rate variability (HRV) analysis. This user-friendly option should be validated in the effort to provide practitioners confidence when monitoring their athletes before implementing such equipment. The objective of this investigation was to examine the relationship and validity between a vagal-related HRV index, rMSSD, when derived from a smartphone application accessible with most operating systems against a frequently used computer software program, Kubios HRV 2.2. R-R intervals were recorded immediately upon awakening over 14 consecutive days using the Elite HRV smartphone application. R-R recordings were then exported into Kubios HRV 2.2 for analysis. The relationship and levels of agreement between rMSSDln derived from Elite HRV and Kubios HRV 2.2 was examined using a Pearson product-moment correlation and a Bland-Altman Plot. An extremely large relationship was identified (r = 0.92; p smartphone HRV application may offer a reliable platform when assessing parasympathetic modulation.

  6. Influence of exercise modality on agreement between gas exchange and heart rate variability thresholds.

    Science.gov (United States)

    Cunha, F A; Montenegro, R A; Midgley, A W; Vasconcellos, F; Soares, P P; Farinatti, P

    2014-08-01

    The main purpose of this study was to investigate the level of agreement between the gas exchange threshold (GET) and heart rate variability threshold (HRVT) during maximal cardiopulmonary exercise testing (CPET) using three different exercise modalities. A further aim was to establish whether there was a 1:1 relationship between the percentage heart rate reserve (%HRR) and percentage oxygen uptake reserve (%VO2 R) at intensities corresponding to GET and HRVT. Sixteen apparently healthy men 17 to 28 years of age performed three maximal CPETs (cycling, walking, and running). Mean heart rate and VO2 at GET and HRVT were 16 bpm (P0.05). There was a strong relationship between GET and HRVT, with R2 ranging from 0.69 to 0.90. A 1:1 relationship between %HRR and % VO2 R was not observed at GET and HRVT. The %HRR was higher during cycling (GET mean difference=7%; HRVT mean difference=11%; both P<0.001), walking (GET mean difference=13%; HRVT mean difference=13%; both P<0.001), or running (GET mean difference=11%; HRVT mean difference=10%; both P<0.001). Therefore, using HRVT to prescribe aerobic exercise intensity appears to be valid. However, to assume a 1:1 relationship between %HRR and % VO2 R at HRVT would probably result in overestimation of the energy expenditure during the bout of exercise.

  7. Computerized analysis of fetal heart rate variability signal during the stages of labor.

    Science.gov (United States)

    Annunziata, Maria Laura; Tagliaferri, Salvatore; Esposito, Francesca Giovanna; Giuliano, Natascia; Mereghini, Flavia; Di Lieto, Andrea; Campanile, Marta

    2016-03-01

    To analyze computerized cardiotocographic (cCTG) parameters (baseline fetal heart rate, baseline FHR; short term variability, STV; approximate entropy, ApEn; low frequency, LF; movement frequency, MF; high frequency, HF) in physiological pregnancy in order to correlate them with the stages of labor. This could provide more information for understanding the mechanisms of nervous system control of FHR during labor progression. A total of 534 pregnant women were monitored on cCTG from the 37th week before the onset of spontaneous labor and during the first and the second stage of labor. Statistical analysis was performed using Kruskal-Wallis test and Wilcoxon rank-sum test with the Bonferroni adjusted α (labor, and the first and second stages of labor. Differences between some of the stages were found for ApEn, LF and for LF/(HF + MF), where the first and the third were reduced and the second was increased. cCTG modifications during labor may reflect the physiologic increased activation of the autonomous nervous system. Using computerized fetal heart rate analysis during labor it may be possible to obtain more information from the fetal cardiac signal, in comparison with the traditional tracing. © 2016 Japan Society of Obstetrics and Gynecology.

  8. Assessing positive emotional states in dogs using heart rate and heart rate variability.

    Science.gov (United States)

    Zupan, Manja; Buskas, Julia; Altimiras, Jordi; Keeling, Linda J

    2016-03-01

    Since most animal species have been recognized as sentient beings, emotional state may be a good indicator of welfare in animals. The goal of this study was to manipulate the environment of nine beagle research dogs to highlight physiological responses indicative of different emotional experiences. Stimuli were selected to be a more or a less positive food (meatball or food pellet) or social reward (familiar person or less familiar person). That all the stimuli were positive and of different reward value was confirmed in a runway motivation test. Dogs were tested individually while standing facing a display theatre where the different stimuli could be shown by lifting a shutter. The dogs approached and remained voluntarily in the test system. They were tested in four sessions (of 20s each) for each of the four stimuli. A test session consisted of four presentation phases (1st exposure to stimulus, post exposure, 2nd exposure, and access to reward). Heart rate (HR) and heart rate variability (HRV) responses were recorded during testing in the experimental room and also when lying resting in a quiet familiar room. A new method of 'stitching' short periods of HRV data together was used in the analysis. When testing different stimuli, no significant differences were observed in HR and LF:HF ratio (relative power in low frequency (LF) and the high-frequency (HF) range), implying that the sympathetic tone was activated similarly for all the stimuli and may suggest that dogs were in a state of positive arousal. A decrease of HF was associated with the meatball stimulus compared to the food pellet and the reward phase (interacting with the person or eating the food) was associated with a decrease in HF and RMSSD (root mean square of successive differences of inter-beat intervals) compared to the preceding phase (looking at the person or food). This suggests that parasympathetic deactivation is associated with a more positive emotional state in the dog. A similar reduction

  9. Heart rate variability and cognitive processing: The autonomic response to task demands.

    Science.gov (United States)

    Luque-Casado, Antonio; Perales, José C; Cárdenas, David; Sanabria, Daniel

    2016-01-01

    This study investigated variations in heart rate variability (HRV) as a function of cognitive demands. Participants completed an execution condition including the psychomotor vigilance task, a working memory task and a duration discrimination task. The control condition consisted of oddball versions (participants had to detect the rare event) of the tasks from the execution condition, designed to control for the effect of the task parameters (stimulus duration and stimulus rate) on HRV. The NASA-TLX questionnaire was used as a subjective measure of cognitive workload across tasks and conditions. Three major findings emerged from this study. First, HRV varied as a function of task demands (with the lowest values in the working memory task). Second, and crucially, we found similar HRV values when comparing each of the tasks with its oddball control equivalent, and a significant decrement in HRV as a function of time-on-task. Finally, the NASA-TLX results showed larger cognitive workload in the execution condition than in the oddball control condition, and scores variations as a function of task. Taken together, our results suggest that HRV is highly sensitive to overall demands of sustained attention over and above the influence of other cognitive processes suggested by previous literature. In addition, our study highlights a potential dissociation between objective and subjective measures of mental workload, with important implications in applied settings. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Individual differences in heart rate variability are associated with the avoidance of negative emotional events.

    Science.gov (United States)

    Katahira, Kentaro; Fujimura, Tomomi; Matsuda, Yoshi-Taka; Okanoya, Kazuo; Okada, Masato

    2014-12-01

    Although the emotional outcome of a choice generally affects subsequent decisions, humans can inhibit the influence of emotion. Heart rate variability (HRV) has emerged as an objective measure of individual differences in the capacity for inhibitory control. In the present study, we investigated how individual differences in HRV at rest are associated with the emotional effects of the outcome of a choice on subsequent decision making using a decision-making task in which emotional pictures appeared as decision outcomes. We used a reinforcement learning model to characterize the observed behaviors according to several parameters, namely, the learning rate and the motivational value of positive and negative pictures. Consequently, we found that individuals with a lower resting HRV exhibited a greater negative motivational value in response to negative pictures, suggesting that these individuals tend to avoid negative pictures compared with individuals with a higher resting HRV. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Some results on convergence rates for probabilities of moderate deviations for sums of random variables

    Directory of Open Access Journals (Sweden)

    Deli Li

    1992-01-01

    Full Text Available Let X, Xn, n≥1 be a sequence of iid real random variables, and Sn=∑k=1nXk, n≥1. Convergence rates of moderate deviations are derived, i.e., the rate of convergence to zero of certain tail probabilities of the partial sums are determined. For example, we obtain equivalent conditions for the convergence of series ∑n≥1(ψ2(n/nP(|Sn|≥nφ(n only under the assumptions convergence that EX=0 and EX2=1, where φ and ψ are taken from a broad class of functions. These results generalize and improve some recent results of Li (1991 and Gafurov (1982 and some previous work of Davis (1968. For b∈[0,1] and ϵ>0, letλϵ,b=∑n≥3((loglognb/nI(|Sn|≥(2+ϵnloglogn.The behaviour of Eλϵ,b as ϵ↓0 is also studied.

  12. Heart Rate Variability Discriminates Competitive Levels in Professional Soccer Players.

    Science.gov (United States)

    Proietti, Riccardo; di Fronso, Selenia; Pereira, Lucas A; Bortoli, Laura; Robazza, Claudio; Nakamura, Fabio Y; Bertollo, Maurizio

    2017-06-01

    Heart rate variability (HRV) has been increasingly used to monitor team sports athletes. Besides the traditional time domain indices (i.e., the SD of successive RR intervals [SDNN] and the root mean square difference of successive normal RR intervals [RMSSD]), recently the use of the stress score (SS), which is an inverse function of the SD2 index derived from the Poincaré plot, and the sympathetic/parasympathetic ratio (S/PS) to monitor soccer players has been proposed. However, the reliability of these new indices and the ability of HRV to differentiate between soccer competitive levels are unknown. The aim of this study was to analyze the reliability of the different HRV-derived indices in professional soccer players during the competitive period and to compare HRV of professional soccer players from 3 teams of distinct competitive levels (i.e., Italian Second Division [2D], European League [EL], and Champions League [CL]). Fifty-four male professional soccer players from 3 different teams of 2 European countries (Italy and Germany) participated in the study. The intraclass correlation coefficient values of the HRV indices varied from 0.78 (very large) to 0.90 (near perfect). The coefficient of variation (CV) values for RMSSD and SDNN were all soccer players and is able to differentiate between international- and national-level players.

  13. Assessment of ventilatory thresholds from heart rate variability in five incremental treadmill tests in cross country skiers

    OpenAIRE

    Mendia Iztueta, Ibai

    2014-01-01

    Incremental treadmill tests are widely used in the field of exercise physiology for the assessment of Ventilatory Thresholds for clinical and sport oriented issues. The assessment of Ventilatory Thresholds (VTs) from Heart Rate Variability (HRV) is a relatively new approach with increasing popularity because it is a non-invasive and economical method. Nevertheless, this has not been used in Cross Country (XC) Skiing, an endurance sport where the knowledge of VTs holds special importance. The ...

  14. Autonomic markers associated with generalized social phobia symptoms: heart rate variability and salivary alpha-amylase.

    Science.gov (United States)

    García-Rubio, María J; Espín, Laura; Hidalgo, Vanesa; Salvador, Alicia; Gómez-Amor, Jesús

    2017-01-01

    The study of autonomic nervous system changes associated with generalized social phobia (GSP) disorder has increased in recent years, showing contradictory results. The present study aimed to evaluate how young people with GSP reacted before, during, and after exposure to the Trier Stress Social Test (TSST), focusing on their autonomic changes (heart rate variability (HRV) and salivary alpha-amylase (sAA)) compared to a control group (non-GSP). Some psychological variables were also considered. Sex was specifically studied as a possible modulator of autonomic fluctuations and psychological state. Eighty young people were randomly distributed into two counterbalanced situations: stress condition (N = 18 and 21 for GSP and non-GSP, respectively) and control condition (N = 21 and 20 for GSP and non-GSP, respectively), where cardiovascular variables were continuously recorded. Psychological questionnaires about mood and perceived stress were filled out, and five saliva samples were collected to analyze sAA. GSP participants showed higher values on low- and high-frequency ratios (HR domains), compared to non-GSP people, during exposure to the TSST, but no differences were observed after the stressor. Furthermore, the two groups did not differ in sAA. Importantly, positive affect in GSP participants was modulated by sex. The present study suggests that the balance between high- and low-frequency domains of HRV is a key cardiovascular marker reflecting the stress response of GSP people, as well the importance of sex in positive affect when facing a stressful situation.

  15. Description, evaluation and clinical decision making according to various fetal heart rate patterns. Inter-observer and regional variability

    DEFF Research Database (Denmark)

    Lidegaard, O; Bøttcher, L M; Weber, Tom

    1992-01-01

    departments, especially between departments far apart. It is concluded that we still need a scientific clarification of which specific heart rate changes are the best predictors of fetal stress. Artificial intelligence programs for interpreting fetal cardiotocograms and ECG signals constitute one promising......At 10 Danish obstetrical departments, 116 residents (42 senior and 74 junior) participated in a study to assess inter-observer and regional variability in the description and evaluation of and clinical decision regarding 11 fetal heart rate patterns. The 11 traces included normal as well...... as pathological patterns, and normal as well as clinically asphyxiated babies. Five antepartum and six intrapartum patterns were included. A total of 1,276 descriptions and evaluations were obtained. The degree of agreement in description of fetal heart rate changes was high regarding the baseline...

  16. Statistical analyses of variability/reproducibility of environmentally assisted cyclic crack growth rate data utilizing JAERI Material Performance Database (JMPD)

    International Nuclear Information System (INIS)

    Tsuji, Hirokazu; Yokoyama, Norio; Nakajima, Hajime; Kondo, Tatsuo

    1993-05-01

    Statistical analyses were conducted by using the cyclic crack growth rate data for pressure vessel steels stored in the JAERI Material Performance Database (JMPD), and comparisons were made on variability and/or reproducibility of the data between obtained by ΔK-increasing and by ΔK-constant type tests. Based on the results of the statistical analyses, it was concluded that ΔK-constant type tests are generally superior to the commonly used ΔK-increasing type ones from the viewpoint of variability and/or reproducibility of the data. Such a tendency was more pronounced in the tests conducted in simulated LWR primary coolants than those in air. (author)

  17. Nocturnal heart rate variability in patients treated with cognitive-behavioral therapy for insomnia.

    Science.gov (United States)

    Jarrin, Denise C; Chen, Ivy Y; Ivers, Hans; Lamy, Manon; Vallières, Annie; Morin, Charles M

    2016-06-01

    Insomnia and reduced heart rate variability (HRV) increase the risk of cardiovascular disease and its precursors; thus, it is important to evaluate whether treatment for insomnia provides cardiovascular safeguards. The present study aimed to evaluate potential cardiovascular benefits of cognitive behavioral therapy for insomnia (CBT-I). The present study included 65 patients treated for chronic insomnia (M = 51.8 years, SD = 10.0; 66.2% female) at a university hospital. Patients received CBT-I over a 6-week period, and change scores from pre- to posttreatment derived from the Insomnia Severity Index, sleep diary, and polysomnography (PSG) were used as indices of sleep improvement. HRV variables (i.e., low frequency [LF], high frequency [HF], and the ratio of low to high frequency [LF:HF ratio]) were derived for Stage 2 (S2) and rapid-eye movement (REM) sleep at pre- and posttreatment. High HF (i.e., parasympathetic activity) and/or low LF:HF ratio (i.e., sympathovagal balance) were used as indices of HRV improvement. Following therapy, sleep improvements, particularly for sleep onset latency, were related with reduced HF in S2 (r = .30, p insomnia symptoms and increased HF in REM (r = -.21, p insomnia treatment might play a role in physiological changes associated with cardiovascular anomalies. Future research is needed to examine the long-term impact of treatment as a preventative tool against insomnia-related morbidity. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  18. On heart rate variability and autonomic activity in homeostasis and in systemic inflammation.

    Science.gov (United States)

    Scheff, Jeremy D; Griffel, Benjamin; Corbett, Siobhan A; Calvano, Steve E; Androulakis, Ioannis P

    2014-06-01

    Analysis of heart rate variability (HRV) is a promising diagnostic technique due to the noninvasive nature of the measurements involved and established correlations with disease severity, particularly in inflammation-linked disorders. However, the complexities underlying the interpretation of HRV complicate understanding the mechanisms that cause variability. Despite this, such interpretations are often found in literature. In this paper we explored mathematical modeling of the relationship between the autonomic nervous system and the heart, incorporating basic mechanisms such as perturbing mean values of oscillating autonomic activities and saturating signal transduction pathways to explore their impacts on HRV. We focused our analysis on human endotoxemia, a well-established, controlled experimental model of systemic inflammation that provokes changes in HRV representative of acute stress. By contrasting modeling results with published experimental data and analyses, we found that even a simple model linking the autonomic nervous system and the heart confound the interpretation of HRV changes in human endotoxemia. Multiple plausible alternative hypotheses, encoded in a model-based framework, equally reconciled experimental results. In total, our work illustrates how conventional assumptions about the relationships between autonomic activity and frequency-domain HRV metrics break down, even in a simple model. This underscores the need for further experimental work towards unraveling the underlying mechanisms of autonomic dysfunction and HRV changes in systemic inflammation. Understanding the extent of information encoded in HRV signals is critical in appropriately analyzing prior and future studies. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Extracting information on the spatial variability in erosion rate stored in detrital cooling age distributions in river sands

    Science.gov (United States)

    Braun, Jean; Gemignani, Lorenzo; van der Beek, Peter

    2018-03-01

    One of the main purposes of detrital thermochronology is to provide constraints on the regional-scale exhumation rate and its spatial variability in actively eroding mountain ranges. Procedures that use cooling age distributions coupled with hypsometry and thermal models have been developed in order to extract quantitative estimates of erosion rate and its spatial distribution, assuming steady state between tectonic uplift and erosion. This hypothesis precludes the use of these procedures to assess the likely transient response of mountain belts to changes in tectonic or climatic forcing. Other methods are based on an a priori knowledge of the in situ distribution of ages to interpret the detrital age distributions. In this paper, we describe a simple method that, using the observed detrital mineral age distributions collected along a river, allows us to extract information about the relative distribution of erosion rates in an eroding catchment without relying on a steady-state assumption, the value of thermal parameters or an a priori knowledge of in situ age distributions. The model is based on a relatively low number of parameters describing lithological variability among the various sub-catchments and their sizes and only uses the raw ages. The method we propose is tested against synthetic age distributions to demonstrate its accuracy and the optimum conditions for it use. In order to illustrate the method, we invert age distributions collected along the main trunk of the Tsangpo-Siang-Brahmaputra river system in the eastern Himalaya. From the inversion of the cooling age distributions we predict present-day erosion rates of the catchments along the Tsangpo-Siang-Brahmaputra river system, as well as some of its tributaries. We show that detrital age distributions contain dual information about present-day erosion rate, i.e., from the predicted distribution of surface ages within each catchment and from the relative contribution of any given catchment to the

  20. Extracting information on the spatial variability in erosion rate stored in detrital cooling age distributions in river sands

    Directory of Open Access Journals (Sweden)

    J. Braun

    2018-03-01

    Full Text Available One of the main purposes of detrital thermochronology is to provide constraints on the regional-scale exhumation rate and its spatial variability in actively eroding mountain ranges. Procedures that use cooling age distributions coupled with hypsometry and thermal models have been developed in order to extract quantitative estimates of erosion rate and its spatial distribution, assuming steady state between tectonic uplift and erosion. This hypothesis precludes the use of these procedures to assess the likely transient response of mountain belts to changes in tectonic or climatic forcing. Other methods are based on an a priori knowledge of the in situ distribution of ages to interpret the detrital age distributions. In this paper, we describe a simple method that, using the observed detrital mineral age distributions collected along a river, allows us to extract information about the relative distribution of erosion rates in an eroding catchment without relying on a steady-state assumption, the value of thermal parameters or an a priori knowledge of in situ age distributions. The model is based on a relatively low number of parameters describing lithological variability among the various sub-catchments and their sizes and only uses the raw ages. The method we propose is tested against synthetic age distributions to demonstrate its accuracy and the optimum conditions for it use. In order to illustrate the method, we invert age distributions collected along the main trunk of the Tsangpo–Siang–Brahmaputra river system in the eastern Himalaya. From the inversion of the cooling age distributions we predict present-day erosion rates of the catchments along the Tsangpo–Siang–Brahmaputra river system, as well as some of its tributaries. We show that detrital age distributions contain dual information about present-day erosion rate, i.e., from the predicted distribution of surface ages within each catchment and from the relative contribution of

  1. Effect of verapamil on heart rate variability after an acute myocardial infarction. Danish Verapamil Infarction Trial II

    DEFF Research Database (Denmark)

    Vaage-Nilsen, M; Rasmussen, Verner

    1998-01-01

    with verapamil significantly reduced sudden death, the aim of the present substudy was to evaluate the effect of verapamil on heart-rate variability in the time and frequency domain, measured in two 5-minute segments during the day and night. Thirty-eight patients were examined by Holter monitoring, at 1 week......-16 months of treatment. In accord with the known reduction of overall heart rate by verapamil, a significant increase of mean NN interval from before to after 1 (P = 0.0004) and 12-16 months (P = 0.004) of treatment was seen in the verapamil, but not in the placebo, group at night. Parameters generally......, the present study indicates that verapamil shifts the autonomic balance to a vagal preponderance or sympathetic attenuation in the postinfarction period....

  2. Estimating the cost of mental loading in a bimodal divided-attention task: Combining reaction time, heart-rate variability and signal-detection theory

    Science.gov (United States)

    Casper, Patricia A.; Kantowitz, Barry H.

    1988-01-01

    Multiple approaches are necessary for understanding and measuring workload. In particular, physiological systems identifiable by employing cardiac measures are related to cognitive systems. One issue of debate in measuring cardiac output is the grain of analysis used in recording and summarizing data. Various experiments are reviewed, the majority of which were directed at supporting or contradicting Lacey's intake-rejection hypothesis. Two of the experiments observed heart rate in operational environments and found virtually no changes associated with mental load. The major problems facing researchers using heart rate variability, or sinus arrhthmia, as a dependent measure have been associated with valid and sensitive scoring and preventing contamination of observed results by influences unrelated to cognition. Spectral analysis of heart rate variability offers two useful procedures: analysis from the time domain and analysis from the frequency domain. Most recently, data have been collected in a divided attention experiment, the performance measures and cardiac measures of which are detailed.

  3. The effect of feed rate and recycle rate variable on leaching process of Na2Zro3 with HCl in continuous stirred tank reactor (CSTR) series

    Science.gov (United States)

    Palupi, Bekti; Supranto, Sediawan, Wahyudi Budi; Setyadji, Moch.

    2017-05-01

    This time, the natural resources of zircon sand is processed into several zirconium products which is utilized for various industries, such as ceramics, glass industry, metal industry and nuclear industry. The process of zircon sand into zirconium products through several stages, one of them is leaching process of Na2ZrO3 with HCl. In this research, several variations of recycle-rate/feed-rate had been done to determine the effect on leaching process. The leaching was processed at temperature of 90°C, ratio of Na2ZrO3:HCl = 1g:30mL, and 142 rotary per minute of stirring speed for 30 minutes with variation of recycle-rate/feed-rate such as 0.478, 0.299, 0.218, 0.171 and 0.141. The diameter size of Na2ZrO3 powder that used are 0.088 to 0.149 mm. This process was carried out in Continuous Stirred Tank Reactor (CSTR) series with recycle. Based on this research, the greater of the recycle-rate/feed-rate variable, the obtained Zr recovery decreased. The correlation between recycle-rate/feed-rate and Zr recovery is shown by the equation y = -146.91x + 103.51, where y is the Zr recovery and x is the recycle-rate/feed-rate. The highest Zr recovery was 90.52% obtained at recycle-rate/feed-rate 0.141. The mathematical modeling involving the probability model P(r) = 2β2r2 exp(-βr2) can be applied to this leaching process with Sum of Squared Errors (SSE) values in the range of 6×10-7 - 7×10-6.

  4. Automatic stress-relieving music recommendation system based on photoplethysmography-derived heart rate variability analysis.

    Science.gov (United States)

    Shin, Il-Hyung; Cha, Jaepyeong; Cheon, Gyeong Woo; Lee, Choonghee; Lee, Seung Yup; Yoon, Hyung-Jin; Kim, Hee Chan

    2014-01-01

    This paper presents an automatic stress-relieving music recommendation system (ASMRS) for individual music listeners. The ASMRS uses a portable, wireless photoplethysmography module with a finger-type sensor, and a program that translates heartbeat signals from the sensor to the stress index. The sympathovagal balance index (SVI) was calculated from heart rate variability to assess the user's stress levels while listening to music. Twenty-two healthy volunteers participated in the experiment. The results have shown that the participants' SVI values are highly correlated with their prespecified music preferences. The sensitivity and specificity of the favorable music classification also improved as the number of music repetitions increased to 20 times. Based on the SVI values, the system automatically recommends favorable music lists to relieve stress for individuals.

  5. Relationship of suicide rates to economic variables in Europe

    DEFF Research Database (Denmark)

    Fountoulakis, Konstantinos N; Kawohl, Wolfram; Theodorakis, Pavlos N

    2014-01-01

    European countries and included the number of deaths by suicide in men and women, the unemployment rate, the gross domestic product (GDP) per capita, the annual economic growth rate and inflation. RESULTS: There was a strong correlation between suicide rates and all economic indices except GPD per capita...... in men but only a correlation with unemployment in women. However, the increase in suicide rates occurred several months before the economic crisis emerged. CONCLUSIONS: Overall, this study confirms a general relationship between the economic environment and suicide rates; however, it does not support...

  6. Impacts of obesity and stress on neuromuscular fatigue development and associated heart rate variability.

    Science.gov (United States)

    Mehta, R K

    2015-02-01

    Obesity and stress are independently associated with decrements in neuromuscular functions. The present study examined the interplay of obesity and stress on neuromuscular fatigue and associated heart rate variability (HRV). Forty-eight non-obese (18.5obese (30⩽BMI) adults performed repetitive handgrip exertions at 30% of their maximum strength until exhaustion in the absence and presence of a mental arithmetic stressor. Dependent measures included gold standard fatigue indicators (endurance time and rate of strength loss), perceived effort and mental demand, heart rate and temporal (RMSSD: root mean square of successive differences between N-N intervals) and spectral (LF/HF: ratio of low to high frequency) indices of HRV. Stress negatively affected endurance time (Pobesity × stress interactions were found on endurance time (P=0.0073), rate of strength loss (P=0.027) and perceived effort (P=0.026), indicating that stress increased fatigability, particularly in the obese group. Both obesity (P=0.001) and stress (P=0.033) independently lowered RMSSD. Finally, stress increased LF/HF ratio (P=0.028) and the interaction of stress and obesity (P=0.008) indicated that this was augmented in the obese group. The present study provides the first evidence that stress-related neuromuscular fatigue development is accelerated in obese individuals. In addition, the stress condition resulted in poorer HRV indices, which is indicative of autonomic dysfunction, particularly in the obese group. These findings indicate that workers are more susceptible to fatigue in high-stress work environments, particularly those with higher BMI, which can increase the risk of musculoskeletal injuries as well as cardiovascular diseases in this population.

  7. Heart rate variability during sleep in healthy term newborns in the early postnatal period

    International Nuclear Information System (INIS)

    Doyle, O M; Korotchikova, I; Boylan, G B; Lightbody, G; Marnane, W; Kerins, D

    2009-01-01

    Normative time- and frequency-domain heart rate variability (HRV) measures were extracted during quiet sleep (QS) and active sleep (AS) periods in 30 healthy babies. All newborn infants studied were less than 12 h old and the sleep state was classified using multi-channel video EEG. Three bands were extracted from the heart rate (HR) spectrum: very low frequency (VLF), 0.01–0.04 Hz; low frequency (LF), 0.04–0.2 Hz, and high frequency (HF), >0.2 Hz. All metrics were averaged across all patients and per sleep state to produce a table of normative values. A noticeable peak corresponding to activity in the RSA band was found in 80% patients during QS and 0% of patients during AS, although some broadband activity was observed. The majority of HRV metrics showed a statistically significant separation between QS and AS. It can be concluded that (i) activity in the RSA band is present during QS in the healthy newborn, in the first 12 h of life, (ii) HRV measures are affected by sleep state and (iii) the averaged HRV metrics reported here could assist the interpretation of HRV data from newborns with neonatal illnesses

  8. Research on the optoacoustic communication system for speech transmission by variable laser-pulse repetition rates

    Science.gov (United States)

    Jiang, Hongyan; Qiu, Hongbing; He, Ning; Liao, Xin

    2018-06-01

    For the optoacoustic communication from in-air platforms to submerged apparatus, a method based on speech recognition and variable laser-pulse repetition rates is proposed, which realizes character encoding and transmission for speech. Firstly, the theories and spectrum characteristics of the laser-generated underwater sound are analyzed; and moreover character conversion and encoding for speech as well as the pattern of codes for laser modulation is studied; lastly experiments to verify the system design are carried out. Results show that the optoacoustic system, where laser modulation is controlled by speech-to-character baseband codes, is beneficial to improve flexibility in receiving location for underwater targets as well as real-time performance in information transmission. In the overwater transmitter, a pulse laser is controlled to radiate by speech signals with several repetition rates randomly selected in the range of one to fifty Hz, and then in the underwater receiver laser pulse repetition rate and data can be acquired by the preamble and information codes of the corresponding laser-generated sound. When the energy of the laser pulse is appropriate, real-time transmission for speaker-independent speech can be realized in that way, which solves the problem of underwater bandwidth resource and provides a technical approach for the air-sea communication.

  9. Physiologic variability at the verge of systemic inflammation: multiscale entropy of heart rate variability is affected by very low doses of endotoxin.

    Science.gov (United States)

    Herlitz, Georg N; Arlow, Renee L; Cheung, Nora H; Coyle, Susette M; Griffel, Benjamin; Macor, Marie A; Lowry, Stephen F; Calvano, Steve E; Gale, Stephen C

    2015-02-01

    Human injury or infection induces systemic inflammation with characteristic neuroendocrine responses. Fluctuations in autonomic function during inflammation are reflected by beat-to-beat variation in heart rate, termed heart rate variability (HRV). In the present study, we determine threshold doses of endotoxin needed to induce observable changes in markers of systemic inflammation, investigate whether metrics of HRV exhibit a differing threshold dose from other inflammatory markers, and investigate the size of data sets required for meaningful use of multiscale entropy (MSE) analysis of HRV. Healthy human volunteers (n = 25) were randomized to receive placebo (normal saline) or endotoxin/lipopolysaccharide (LPS): 0.1, 0.25, 0.5, 1.0, or 2.0 ng/kg administered intravenously. Vital signs were recorded every 30 min for 6 h and then at 9, 12, and 24 h after LPS. Blood samples were drawn at specific time points for cytokine measurements. Heart rate variability analysis was performed using electrocardiogram epochs of 5 min. Multiscale entropy for HRV was calculated for all dose groups to scale factor 40. The lowest significant threshold dose was noted in core temperature at 0.25 ng/kg. Endogenous tumor necrosis factor α and interleukin 6 were significantly responsive at the next dosage level (0.5 ng/kg) along with elevations in circulating leukocytes and heart rate. Responses were exaggerated at higher doses (1 and 2 ng/kg). Time domain and frequency domain HRV metrics similarly suggested a threshold dose, differing from placebo at 1.0 and 2.0 ng/kg, below which no clear pattern in response was evident. By applying repeated-measures analysis of variance across scale factors, a significant decrease in MSE was seen at 1.0 and 2.0 ng/kg by 2 h after exposure to LPS. Although not statistically significant below 1.0 ng/kg, MSE unexpectedly decreased across all groups in an orderly dose-response pattern not seen in the other outcomes. By using repeated-measures analysis of

  10. Auditory stimulation with music influences the geometric indices of heart rate variability in response to the postural change maneuver.

    Science.gov (United States)

    de Castro, Bianca C R; Guida, Heraldo L; Roque, Adriano L; de Abreu, Luiz Carlos; Ferreira, Celso; Marcomini, Renata S; Monteiro, Carlos B M; Adami, Fernando; Ribeiro, Viviane F; Fonseca, Fernando L A; Santos, Vilma N S; Valenti, Vitor E

    2014-01-01

    It is poor in the literature the behavior of the geometric indices of heart rate variability (HRV) during the musical auditory stimulation. The objective is to investigate the acute effects of classic musical auditory stimulation on the geometric indexes of HRV in women in response to the postural change maneuver (PCM). We evaluated 11 healthy women between 18 and 25 years old. We analyzed the following indices: Triangular index, Triangular interpolation of RR intervals and Poincarι plot (standard deviation of the instantaneous variability of the beat-to beat heart rate [SD1], standard deviation of long-term continuous RR interval variability and Ratio between the short - and long-term variations of RR intervals [SD1/SD2] ratio). HRV was recorded at seated rest for 10 min. The women quickly stood up from a seated position in up to 3 s and remained standing still for 15 min. HRV was recorded at the following periods: Rest, 0-5 min, 5-10 min and 10-15 min during standing. In the second protocol, the subject was exposed to auditory musical stimulation (Pachelbel-Canon in D) for 10 min at seated position before standing position. Shapiro-Wilk to verify normality of data and ANOVA for repeated measures followed by the Bonferroni test for parametric variables and Friedman's followed by the Dunn's posttest for non-parametric distributions. In the first protocol, all indices were reduced at 10-15 min after the volunteers stood up. In the protocol musical auditory stimulation, the SD1 index was reduced at 5-10 min after the volunteers stood up compared with the music period. The SD1/SD2 ratio was decreased at control and music period compared with 5-10 min after the volunteers stood up. Musical auditory stimulation attenuates the cardiac autonomic responses to the PCM.

  11. Auditory stimulation with music influences the geometric indices of heart rate variability in response to the postural change maneuver

    Directory of Open Access Journals (Sweden)

    Bianca C. R. de Castro

    2014-01-01

    Full Text Available It is poor in the literature the behavior of the geometric indices of heart rate variability (HRV during the musical auditory stimulation. The objective is to investigate the acute effects of classic musical auditory stimulation on the geometric indexes of HRV in women in response to the postural change maneuver (PCM. We evaluated 11 healthy women between 18 and 25 years old. We analyzed the following indices: Triangular index, Triangular interpolation of RR intervals and Poincarι plot (standard deviation of the instantaneous variability of the beat-to beat heart rate [SD1], standard deviation of long-term continuous RR interval variability and Ratio between the short - and long-term variations of RR intervals [SD1/SD2] ratio. HRV was recorded at seated rest for 10 min. The women quickly stood up from a seated position in up to 3 s and remained standing still for 15 min. HRV was recorded at the following periods: Rest, 0-5 min, 5-10 min and 10-15 min during standing. In the second protocol, the subject was exposed to auditory musical stimulation (Pachelbel-Canon in D for 10 min at seated position before standing position. Shapiro-Wilk to verify normality of data and ANOVA for repeated measures followed by the Bonferroni test for parametric variables and Friedman′s followed by the Dunn′s posttest for non-parametric distributions. In the first protocol, all indices were reduced at 10-15 min after the volunteers stood up. In the protocol musical auditory stimulation, the SD1 index was reduced at 5-10 min after the volunteers stood up compared with the music period. The SD1/SD2 ratio was decreased at control and music period compared with 5-10 min after the volunteers stood up. Musical auditory stimulation attenuates the cardiac autonomic responses to the PCM.

  12. Modifiable variables in physical therapy education programs associated with first-time and three-year National Physical Therapy Examination pass rates in the United States

    Directory of Open Access Journals (Sweden)

    Chad Cook

    2015-09-01

    Full Text Available Purpose: This study aimed to examine the modifiable programmatic characteristics reflected in the Commission on Accreditation in Physical Therapy Education (CAPTE Annual Accreditation Report for all accredited programs that reported pass rates on the National Physical Therapist Examination, and to build a predictive model for first-time and three-year ultimate pass rates. Methods: This observational study analyzed programmatic information from the 185 CAPTE-accredited physical therapy programs in the United States and Puerto Rico out of a total of 193 programs that provided the first-time and three-year ultimate pass rates in 2011. Fourteen predictive variables representing student selection and composition, clinical education length and design, and general program length and design were analyzed against first-time pass rates and ultimate pass rates on the NPTE. Univariate and multivariate multinomial regression analysis for first-time pass rates and logistic regression analysis for three-year ultimate pass rates were performed. Results: The variables associated with the first-time pass rate in the multivariate analysis were the mean undergraduate grade point average (GPA and the average age of the cohort. Multivariate analysis showed that mean undergraduate GPA was associated with the three-year ultimate pass rate. Conclusions: Mean undergraduate GPA was found to be the only modifiable predictor for both first-time and three-year pass rates among CAPTE-accredited physical therapy programs.

  13. Inter-seasonal variability in baseflow recession rates: The role of aquifer antecedent storage in central California watersheds

    Science.gov (United States)

    Bart, Ryan; Hope, Allen

    2014-11-01

    Baseflow recession rates vary inter-seasonally in many watersheds. This variability is generally associated with changes in evapotranspiration; however, an additional and less studied control over inter-seasonal baseflow recession rates is the effect of aquifer antecedent storage. Understanding the role of aquifer antecedent storage on baseflow recession rates is crucial for Mediterranean-climate regions, where seasonal asynchronicity of precipitation and energy levels produces large inter-seasonal differences in aquifer storage. The primary objective of this study was to elucidate the relation between aquifer antecedent storage and baseflow recession rates in four central California watersheds using antecedent streamflow as a surrogate for watershed storage. In addition, a parsimonious storage-discharge model consisting of two nonlinear stores in parallel was developed as a heuristic tool for interpreting the empirical results and providing insight into how inter-seasonal changes in aquifer antecedent storage may affect baseflow recession rates. Antecedent streamflow cumulated from the beginning of the wateryear was found to be the strongest predictor of baseflow recession rates, indicating that inter-seasonal differences in aquifer storage are a key control on baseflow recession rates in California watersheds. Baseflow recession rates and antecedent streamflow exhibited a negative power-law relation, with baseflow recession rates decreasing by up to two orders of magnitude as antecedent streamflow levels increased. Inference based on the storage-discharge model indicated that the dominant source of recession flow shifted from small, rapid response aquifers at the beginning of the wet season to large, seasonal aquifers as the wet season progressed. Aquifer antecedent storage in California watersheds should be accounted for along with evapotranspiration when characterizing baseflow recession rates.

  14. CHARACTERISTIC OF PARAMETERS OF HEART RATE VARIABILITY IN PATIENTS WITH DIFFICULT-TO-CONTROL AND CONTROLLED ARTERIAL HYPERTENSION

    OpenAIRE

    Tymoshenko O. S.; Yabluchansky M. I.; Martynenko O. V.

    2017-01-01

    Parameters of heart rate variability (HRV) were studied in 112 patients with arterial hypertension (AH) aged 58.5 ± 9 years (60 patients with difficult-to-control arterial hypertension (DTCAH) and 52 patients with controlled arterial hypertension (CAH)). The control group was consisted of 20 conditionally healthy persons of the same sex and age. It has been established that patients with AH were characterized by decrease in the level of total power of the HRV spectrum, the power of the high-f...

  15. Heart Rate Variability is a Moderating Factor in the Workload-Injury Relationship of Competitive CrossFit™ Athletes

    OpenAIRE

    Williams, Sean; Booton, Thomas; Watson, Matthew; Rowland, Daniel; Altini, Marco

    2017-01-01

    Heart rate variability (HRV) is a popular tool for monitoring training adaptation and readiness in athletes, but it also has the potential to indicate early signs of somatic tissue overload prior to the onset of pain or fully developed injury. Therefore, the aim of this study was to investigate the interaction between HRV, workloads, and risk of overuse problems in competitive CrossFit™ athletes. Daily resting HRV and workloads (duration × session-RPE) were recorded in six competitive CrossFi...

  16. Is meditation always relaxing? Investigating heart rate, heart rate variability, experienced effort and likeability during training of three types of meditation.

    Science.gov (United States)

    Lumma, Anna-Lena; Kok, Bethany E; Singer, Tania

    2015-07-01

    Meditation is often associated with a relaxed state of the body. However, meditation can also be regarded as a type of mental task and training, associated with mental effort and physiological arousal. The cardiovascular effects of meditation may vary depending on the type of meditation, degree of mental effort, and amount of training. In the current study we assessed heart rate (HR), high-frequency heart rate variability (HF-HRV) and subjective ratings of effort and likeability during three types of meditation varying in their cognitive and attentional requirements, namely breathing meditation, loving-kindness meditation and observing-thoughts meditation. In the context of the ReSource project, a one-year longitudinal mental training study, participants practiced each meditation exercise on a daily basis for 3 months. As expected HR and effort were higher during loving-kindness meditation and observing-thoughts meditation compared to breathing meditation. With training over time HR and likeability increased, while HF-HRV and the subjective experience of effort decreased. The increase in HR and decrease in HF-HRV over training was higher for loving-kindness meditation and observing-thoughts meditation compared to breathing meditation. In contrast to implicit beliefs that meditation is always relaxing and associated with low arousal, the current results show that core meditations aiming at improving compassion and meta-cognitive skills require effort and are associated with physiological arousal compared to breathing meditation. Overall these findings can be useful in making more specific suggestions about which type of meditation is most adaptive for a given context and population. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Heart rate and heart rate variability in dogs with different degrees of myxomatous mitral valve disease

    DEFF Research Database (Denmark)

    Rasmussen, Caroline Elisabeth; Falk, Bo Torkel; Zois, Nora Elisabeth

    2011-01-01

    atrial area using color Doppler mapping) and no murmur, 2) CKCS with mild MR (20%50%) and no clinical signs of HF, 4) CKCS in HF (HF defined as left atrium to aortic root ratio (LA/Ao) >1.5, clinical signs of HF and furosemide responsiveness) and 5) non......-CKCS in HF. Dogs in HF were allowed HF therapy. Both HR and HRV were analysed over a 24-hour period, while HRV were also analysed over a 6-hour nightly period. Analyses of variance were performed with HR or HRV as response variables and the explanatory variables dog group and echocardiographic indices...

  18. [CARDIOREABILITATION PECULIARITIES AND CORRECTION OF VIOLATIONS OF SISTOLIC, DIASOLIC FUNCTION AND HEART RATE VARIABILITY IN PATIENTS WITH ACUTE CORONARY SYNDROME AND CORONARY ARTERY REVASCULARIZATION].

    Science.gov (United States)

    Shved, M; Tsuglevych, L; Kyrychok, I; Levytska, L; Boiko, T; Kitsak, Ya

    2017-04-01

    In patients with acute coronary syndrome (ACS) who underwent coronary arteries revascularization, violations of hemodynamics, metabolism and heart rate variability often develop in the postoperative period, therefore, the goal of the study was to establish the features of disturbances and the effectiveness of correction of left ventricular systolic and diastolic dysfunction and heart rate variability in stages of cardiorehabilitation in patients with acute coronary syndrome who underwent coronary arteries revascularization. The experimental group included 40 patients with ACS in the postoperative period who underwent balloon angioplasty and stenting of the coronary arteries (25 patients with ST-segment elevation ACS and 15 patients without ST-segment elevation ACS). The age of examined patients was 37 to 74 years, an average of 52.6±6.7 years. The control group consisted of 20 patients, comparable in age and clinico-laboratory manifestations of ACS, who underwent drug treatment with direct anticoagulants, double antiplatelet therapy, β-blockers, ACE inhibitors and statins. Clinical efficacy of cardiorespiratory process in patients of both groups was assessed by the dynamics of general clinical symptoms and parameters of natriuretic propeptide, systolic and diastolic function of the left ventricle and heart rate variability. In the initial state, clinical and laboratory-instrumental signs of myocardial ischemia disappear in patients with ACS undergoing surgical revascularization of the coronary arteries, but clinical and subclinical manifestations of heart failure were diagnosed. The use of the accelerated program of cardiac rehabilitation already during the first month of studies leads to a decreasement of the signs of systolic and diastolic dysfunction, the level of NT-proBNP and improve in the variability of the heart rhythm wich significantly improves the life quality of patients with ACS. To monitor the effectiveness and safety of cardiac rehabilitation in

  19. Emotionally Excited Eyeblink-Rate Variability Predicts an Experience of Transportation into the Narrative World

    Directory of Open Access Journals (Sweden)

    Ryota eNomura

    2015-04-01

    Full Text Available Collective spectator communications such as oral presentations, movies, and storytelling performances are ubiquitous in human culture. This study investigated the effects of past viewing experiences and differences in expressive performance on an audience’s transportive experience into a created world of a storytelling performance. In the experiment, 60 participants (mean age = 34.12 yrs., SD = 13.18 yrs., range 18–63 yrs. were assigned to watch one of two videotaped performances that were played (1 in an orthodox way for frequent viewers and (2 in a modified way aimed at easier comprehension for first-time viewers. Eyeblink synchronization among participants was quantified by employing distance-based measurements of spike trains, Dspike and Dinterval (Victor & Purpura, 1997. The results indicated that even non-familiar participants’ eyeblinks were synchronized as the story progressed and that the effect of the viewing experience on transportation was weak. Rather, the results of a multiple regression analysis demonstrated that the degrees of transportation could be predicted by a retrospectively reported humor experience and higher real-time variability (i.e., logarithmic transformed standard deviation of inter blink intervals during a performance viewing. The results are discussed from the viewpoint in which the extent of eyeblink synchronization and eyeblink-rate variability acts as an index of the inner experience of audience members.

  20. The Influence of Loading Rate and Variable Temperatures on Microbial Communities in Anaerobic Digesters

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    Richard J. Ciotola

    2014-02-01

    Full Text Available The relationship between seasonal temperatures, organic loading rate (OLR and the structure of archaeal communities in anaerobic digesters was investigated. Previous studies have often assessed archaeal community structure at fixed temperatures and constant OLRs, or at variable temperatures not characteristic of temperate climates. The goal of this study was to determine the maximum OLR that would maintain a balanced microbial ecosystem during operation in a variable temperature range expected in a temperate climate (27–10 °C. Four-liter laboratory digesters were operated in a semi-continuous mode using dairy cow manure as the feedstock. At OLRs of 1.8 and 0.8 kg VS/m3·day the digesters soured (pH < 6.5 as a result of a decrease in temperature. The structure of the archaeal community in the sour digesters became increasingly similar to the manure feedstock with gains in the relative abundance of hydrogenotrophic methanogens. At an OLR of 0.3 kg VS/m3·day the digesters did not sour, but the archaeal community was primarily hydrogenotrophic methanogens. Recommendations for operating an ambient temperature digester year round in a temperate climate are to reduce the OLR to at least 0.3 kg VS/m3·day in colder temperatures to prevent a shift to the microbial community associated with the sour digesters.