Digital Recording System Research Articles

A more precise, repeatable and diagnostic alternative to surface electromyography – an appraisal of the clinical utility of acoustic myography

Acoustic myography (AMG) enables a detailed and accurate measurement of those muscles involved in a particular movement and is independent of electrical signals between the nerve and muscle, measuring solely muscle contractions, unlike surface electromyography (sEMG). With modern amplifiers and digital sound recording systems, measurements during physical activity both inside and outside a laboratory setting are now possible and accurate. Muscle sound gives a representation of the work of each muscle group during a complex movement, and under certain forms of movement even reveals both concentric and eccentric activity, something that sEMG is incapable of. Recent findings suggest that AMG has a number of advantages over sEMG, being simple to use, accurate and repeatable as well as being intuitive to interpret. The AMG signal comprises three physiological parameters, namely efficiency/coordination (E-score), spatial summation (S-score) and temporal summation (T-score). It is concluded that modern AMG units have the potential to accurately assess patients with neuromuscular and musculoskeletal complaints in hospital clinics, home monitoring situations as well as sports settings.

Changes in cardiovascular responses to chemoreflex activation of rats recovered from protein restriction are not related to AT1 receptors.

What is the central question of this study? In this study, we sought to investigate whether cardiovascular responses to peripheral chemoreflex activation of rats recovered from protein restriction are related to activation of AT1 receptors. What is the main finding and its importance? This study highlights the fact that angiotensinergic mechanisms activated by AT1 receptors do not support increased responses to peripheral chemoreflex activation by KCN in rats recovered from protein restriction. Also, we found that protein restriction led to increased resting ventilation in adult rats, even after recovery. The effects of a low-protein diet followed by recovery on cardiorespiratory responses to peripheral chemoreflex activation were tested before and after systemic angiotensinII type1 (AT1 ) receptor antagonism. Male Fischer rats were divided into control and recovered (R-PR) groups after weaning. The R-PR rats were fed a low-protein (8%) diet for 35 days and recovered with a normal protein (20%) diet for 70 days. Control rats received a normal protein diet for 105 days (CG105 ). After cannulation surgery, mean arterial pressure, heart rate, respiratory frequency, tidal volume and minute ventilation were acquired using a digital recording system in freely moving rats. The role of angintensin II was evaluated by systemic antagonism of AT1 receptors with losartan (20mgkg-1 i.v.). The peripheral chemoreflex was elicited by increasing doses of KCN (20-160μgkgmin-1 , i.v.). At baseline, R-PR rats presented increased heart rate and minute ventilation (372±34beatsmin-1 and 1.274±377mlkg-1 min-1 ) compared with CG105 animals (332±22beatsmin-1 and 856±112mlkg-1 min-1 ). Mean arterial pressure was not different between the groups. Pressor and bradycardic responses evoked by KCN (60μgkg-1 ) were increased in R-PR (+45±13mmHg and -77±47beatsmin-1 ) compared with CG105 rats (+25±17mmHg and -27±28beatsmin-1 ), but no difference was found in the tachypnoeic response. These differences were preserved after losartan. The data suggest that angiotensinII acting on AT1 receptors may not be associated with the increased heart rate, increased minute ventilation and acute cardiovascular responses to peripheral chemoreflex activation in rats that underwent postweaning protein restriction followed by recovery.

Remote Cameras Reveal Experimental Artifact in a Study of Seed Predation in a Semi-Arid Shrubland.

Granivorous animals may prefer to predate or cache seed of certain plant species over others. Multiple studies have documented preference for larger, non-native seed by granivores. To accomplish this, researchers have traditionally used indirect inference by relating patterns of seed removal to the species composition of the granivorous animal community. To measure seed removal, researchers present seed to granivorous animals in the field using equipment intended to exclude certain animal taxa while permitting access to others. This approach allows researchers to differentiate patterns of seed removal among various taxa (e.g., birds, small mammals, and insects); however, it is unclear whether the animals of interest are freely using the exclusion devices, which may be a hindrance to discovering the seed dishes. We used video observation to perform a study of seed predation using a custom-built, infrared digital camera and recording system. We presented native and non-native seed mixtures in partitioned Petri dishes both within and outside of exclusion cages. The exclusion cages were intended to allow entrance by rodent taxa while preventing entrance by rabbits and birds. We documented all seed removal visits by granivorous animals, which we identified to the genus level. Genera exhibited varying seed removal patterns based on seed type (native vs. non-native) and dish type (open vs. enclosed). We documented avoidance of the enclosed dishes by all but one rodent taxa, even though these dishes were intended to be used freely by rodents. This suggests that preference for non-native seed occurs differentially among granivorous animals in this system; however, interpretation of these nuanced results would be difficult without the benefit of video observation. When feasible, video observation should accompany studies using in situ equipment to ensure incorrect assumptions do not lead to inappropriate interpretation of results.

Time-frequency analysis of bird songs and neurobehavioral study of the “Catbird Dumetella carolinensis”

There is a commonality between the acquisition of spoken language in human infants and the acquisition of bird songs at the behavioral, neural, genetic, and cognitive levels. Similarities between how birds learn their language and how humans learn is believed to be fundamentally related to the way the brain works. Although the effects of the environment on hearing sensations, and hence the behaviors seems intuitive, it is not yet fully understood. In this paper, we use common digital recording systems to study bird songs in their natural habitat. Then by utilizing the principals of signal processing and spectral analysis individual syllabi are identified and studied for various songs. With the knowledge of the environment from direct measurement and the change in background noise level, the behavior of birds can be studied and documented. This technique was applied to recordings of Dumetella carolinensis (Gray Catbird) in the North East United States. It is shown that in spite of the natural instinct, the catbirds do not easily change their behavior at the onset of loud transient industrial sound. This may be related to the fact that the birds have already been exposed and have learned to live in noisy cosmopolitan environments.

In vivo characterization of a versatile 8-channel digital biopotential recording system with sub-μVRMS input noise.

This work presents the design and testing of an integrated 8-channel CMOS biopotential recording chip, consisting of low-noise input stages, tunable second stage, a multiplexer, and two analog-to-digital converters (ADC). Through its variable supply concept, the integrated input-referred noise of the first stage is selectable from 1.5 down to 0.63 μVRMS (ISS = 200 μA), which is superior to standard laboratory recording systems. The device features variable lower and upper corner frequencies, and outputs two digital 16-bit data streams at 62.5 kS/s. The chip die was fabricated in X-Fab 0.35 μm CMOS technology and has an area of 10 mm2.

Message Concealment System Of Voice Signals Implemented on FPGA

This work introduces the architecture and the implementation on FPGA of a system which realizes the message concealment of voice signals, hiding it in an apparent noise coming from their own wavelet components of the signal. The output of the system appears as a noisy signal in which the original message cannot be recognized. This system can be applied to analog or digital systems for voice transmission, as well as to digital recording systems which require concealment of the relevant information. The system introduced in this work is different of steganographic systems, because this system uses the wavelet components of signal in order to conceal the message of the signal in itself. The voice coder system and voice decoder system were implemented and tested using the FPGA design platform SPARTAN 3AN starter kit, using 30% of resources of the FPGA. Voice coder and voice decoder systems both operate in real time, exhibiting a delay because a latency of 6.2 ms, when operate with a data input rate of 10000 samples/s.

Mobile Digital Recording: Adequacy of the iRig and iOS Device for Acoustic and Perceptual Analysis of Normal Voice

To determine whether the iRig and iOS device recording system is comparable with a standard computer recording system for digital voice recording. Thirty-seven vocally healthy adults, between ages 20 and 62, with a mean age of 33.9 years, 13 males and 24 females, were recruited. Recordings were simultaneously digitalized in an iPad and iPhone using a unidirectional condenser microphone for smartphones/tablets (iRig Mic, IK Multimedia) and in a computer laptop (Dell-Inspiron) using a unidirectional condenser microphone (Samson-CL5) connected to a preamplifier with phantom power. Both microphones were lined up at an equal fixed distance from the subject's mouth. Speech tasks consisted of a sustained vowel "ah" at comfortable pitch/loudness, counting from 1 to 10, and a glissando "ah" from a low to a high note. The samples captured on the iOS devices were transferred via SoundCloud in WAV format, and analyzed using the Praat software. The acoustic parameters measured were mean, min, and max F0, SD F0, jitter local, jitter rap, jitter ppq5, jitter ddp, shimmer local, shimmer local-dB, shimmer apq3, shimmer apq5, shimmer apq11, shimmer dda, NHR, and HNR. There were no statistically significant differences for any parameter and speech task analyzed for both iOS devices as compared with the gold standard computer/preamp system (all P values>0.050). In addition, there were no statistical differences in the perceptual identification of the recordings among devices (P < 0.001). In the present study, the iRig and iOS device may provide reliable digital recording of normal voices.

Low frequency acoustic signals associated with rock falls, thunderstorms, and wind turbulences in field environment

This paper characterized the observed low frequency acoustic signals generated by rock falls, thunderstorm, and wind turbulence in large rocky landslide. A digital infrasonic recording system was deployed on site to capture real-time low frequency acoustic signals associated with rock falls. An advanced non-stationary signal analysis method, i.e. Empirical Mode Decomposition (EMD), was applied to get insight to the characteristics of the low frequency acoustic signals induced by the hazards. Joint time–frequency distribution spectra technique was used to detect distinctive features of the events. The study shows that the low frequency acoustic signals can be excited by rock falls, thunderstorm and wind turbulence in the field environment, but the signal varies in both time domain and frequency domain with different patterns depending on the physical processes. The results demonstrated that the EMD-based signal processing technique is capable of extracting distinctive features to differentiate acoustic signals in real environment.

Continuity matters: Examining the ‘information gap’ in transfer from Residential Aged Care, ambulance to emergency triage in southern Tasmania

BackgroundTransfer of older people from Residential Aged Care Facilities to Emergency Departments requires multiple comprehensive handovers across different services. Significant information gaps exist in transferred information despite calls for standards. AimTo investigate: (1) presence of minimum standard elements in the transfer text written by RACF nurses, paramedics and ED triage nurses, and (2) the transfer documentation used by services. MethodsWe analysed retrospective cross-sectional transfer narratives from the digital medical record system of an Australian tertiary referral hospital using the mnemonic SBAR (Situation, Background, Assessment Recommendation) as the measure of comprehensiveness. Transfer documents from 3 groups were also reviewed. FindingsInclusion of elements from SBAR was inconsistent across transfer. Rather, the written narratives focused on concerns relevant to the immediate priority, the type of information imposed by the document(s) in use, and clinical role of the author. ConclusionTransfer documentation from Residential Aged Care nurses, paramedics and ED triage nurses do not contain comprehensive information of older persons complex conditions. Better communication between non-affiliated organisations is needed to improve timely appropriate care for RACF residents.

Pushing the Paperless Envelope

AbstractArchaeological documentation is in the midst of a technological shift as recording systems transition from paper-based forms to digital formats. Digital systems effectively replicate the information recorded on paper forms, while also offering recording advantages for archaeologists in the field. In addition to such logistical contributions to archaeological workflows, digital technology also has tremendous potential to transform the ways that archaeology is done by shifting how we see our sites, and how we document them through diverse data types. With the goal of exploring this potential, we developed a tablet-based relational database, using FileMaker, which provides the ability to simultaneously record specific characteristics of artifacts and features according to two cultural perspectives—modern archaeological understandings and also those of the Classic Maya. In this article, we describe the database and discuss the results of a pilot field season using the database to record excavations at the site of Say Kah, Belize. Our experiences yield several broader reflections on the impact of using digital recording systems both for practical advantage and for productive shifts in perception.

Building up Systematic Client-Centred Data as a Base for Clinical Outcome within Outpatient Neurorehabilitation

Objective: This study describes the development and use of a specific database supporting personnel within outpatient neurological rehabilitation to reflect on existing interventions and improve future rehabilitation. Methods: Five outpatient rehabilitation centres in one county council in Sweden were involved in developing and implementing a systematic data collection template within the existing digital medical record system. Data were collected to get more information on the effects of outpatient stroke rehabilitation in patients who received rehabilitation the first year after a stroke (ICD-I64) and patients who received further rehabilitation 1 year or more after a stroke (ICD-I69). Data analysis included evaluation of balance, movement, activity/participation, health-related quality of life, and self-rated health. Results: The ICD-I64 group had positive results after treatment (p < 0.05) for all variables and the ICD-I69 group had positive results for balance and activity/participation. Conclusions: The use of systematic data collection provided a platform for employees and managers to discuss and use clinical results to improve the type and quality of rehabilitation interventions.

Application of video recording technology to improve husbandry and reproduction in the carmine bee-eater (Merops n. nubicus).

Incorporating technology with research is becoming increasingly important to enhance animal welfare in zoological settings. Video technology is used in the management of avian populations to facilitate efficient information collection on aspects of avian reproduction that are impractical or impossible to obtain through direct observation. Disney's Animal Kingdom(®) maintains a successful breeding colony of Northern carmine bee-eaters. This African species is a cavity nester, making their nesting behavior difficult to study and manage in an ex situ setting. After initial research focused on developing a suitable nesting environment, our goal was to continue developing methods to improve reproductive success and increase likelihood of chicks fledging. We installed infrared bullet cameras in five nest boxes and connected them to a digital video recording system, with data recorded continuously through the breeding season. We then scored and summarized nesting behaviors. Using remote video methods of observation provided much insight into the behavior of the birds in the colony's nest boxes. We observed aggression between birds during the egg-laying period, and therefore immediately removed all of the eggs for artificial incubation which completely eliminated egg breakage. We also used observations of adult feeding behavior to refine chick hand-rearing diet and practices. Although many video recording configurations have been summarized and evaluated in various reviews, we found success with the digital video recorder and infrared cameras described here. Applying emerging technologies to cavity nesting avian species is a necessary addition to improving management in and sustainability of zoo avian populations.

Evaluating the Quality of Cardiopulmonary Resuscitation in the Emergency Department by Real-Time Video Recording System.

ObjectivesTo compare cardiopulmonary resuscitation (CPR) quality between manual CPR and miniaturized chest compressor (MCC) CPR. To improve CPR quality through evaluating the quality of our clinical work of resuscitation by real-time video recording system.MethodsThe study was a retrospective observational study of adult patients who experienced CPR at the emergency department of Shanghai Tenth People’s Hospital from March 2013 to August 2014. All the performance of CPR were checked back by the record of “digital real-time video recording system”. Average chest compression rate, actual chest compression rate, the percentage of hands-off period, time lag from patient arrival to chest compression, time lag from patient arrival to manual ventilation, time lag from patient arrival to first IV establish were compared. Causes of chest compression hands-off time were also studied.Results112 cases of resuscitation attempts were obtained. Average chest compression rate was over 100 compression per minute (cpm) in the majority of cases. However, indicators such as percentage of hands-off periods, time lag from patient arrival to the first manual ventilation and time lag from patient arrival to the first IV establish seemed to be worse in the manual CPR group compared to MCC CPR group. The saving of operators change time seemed to counteract the time spent on MCC equipment. Indicators such as percentage of hands-off periods, time lag between patient arrival to the first chest compression, time lag between patient arrival to the first manual ventilation and time lag from patient arrival to the first IV establish may influence the survival.ConclusionOur CPR quality remained to be improved. MCC may have a potentially positive role in CPR.

High-fidelity digital recording and playback sphygmomanometry system: device description and proof of concept.

This study describes the development of a new digital sphygmocorder (DS-II), which allows the digital recording and playback of the Korotkoff sounds, together with cuff pressure waveform, and its performance in a pilot validation study. A condenser microphone and stethoscope head detect Korotkoff sounds and an electronic chip, dedicated to audio-signal processing, is used to record high-quality sounds. Systolic and diastolic blood pressure (SBP/DBP) are determined from the recorded signals with an automatic beat detection algorithm that displays the cuff pressure at each beat on the monitor. Recordings of Korotkoff sounds, with the cuff pressure waveforms, and the simultaneous on-site assessments of SBP/DBP were performed during 100 measurements in 10 individuals. The observers reassessed the recorded signals to verify their accuracy and differences were calculated. The features of the high-fidelity DS-II, the technical specifications and the assessment procedures utilizing the playback software are described. Interobserver absolute differences (mean±SD) in measurements were 0.7±1.1/1.3±1.3 mmHg (SBP/DBP) with a mercury sphygmomanometer and 0.3±0.9/0.8±1.2 mmHg with the DS-II. The absolute DS-II mercury sphygmomanometer differences were 1.3±1.9/1.5±1.3 mmHg (SBP/DBP). The high-fidelity DS-II device presents satisfactory agreement with simultaneous measurements of blood pressure with a mercury sphygmomanometer. The device will be a valuable methodology for validating new blood pressure measurement technologies and devices.

Calibrating a Contrast-Sensitivity Test Chart for Validating Visual Representations

Because of differences between how a human and a camera (or digital recording system) acquire and process information, a representation (e.g., a photograph) of a scene may vary in how accurately it portrays what a human would perceive, particularly at low illumination levels. Ayres (1996) described a methodology by which a representation can be matched to observations made at the scene. Central to this process is the utilization of a reference chart to validate the representation. The efficacy of the original chart has been documented empirically; however, its utility can be restricted under certain lighting and viewing conditions. The current paper introduces and tests new reference charts designed to offer a wider range of applicability and with finer gradations of contrast. The new charts were found to be useful at illumination levels ranging from approximately 0.05 to 10.0 footcandles. Potential applications for the charts, including forensic purposes, are discussed.

A novel and inexpensive digital system for eye movement recordings using magnetic scleral search coils

After their introduction by Robinson (IEEE Trans Biomed Eng 10:137-145, 1963), magnetic scleral search coils quickly became an accepted standard for precise eye movement recordings. While other techniques such as video-oculography or electro-oculography may be more suitable for routine applications, search coils still provide the best low-noise and low-drift characteristics paired with the highest temporal and spatial resolution. The problem with search coils is that many research laboratories still have their large and expensive coil systems installed and are acquiring eye movement data with old, analog technology. Typically, the number of recording channels is limited and modifications to an existing search coil system can be difficult. We propose a system that allows to retro-fit an existing analog search coil system to become a digital recording system. The system includes digital data acquisition boards and a reference coil as the hardware part, receiver software, and a new calibration method. The circuit design has been kept simple and robust, and the proposed software calibration allows the calibration of a single coil within a few seconds.

The Source Parameters of Echolocation Clicks from Captive and Free-Ranging Yangtze Finless Porpoises (Neophocaena asiaeorientalis asiaeorientalis).

The clicks of Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis) from 7 individuals in the tank of Baiji aquarium, 2 individuals in a netted pen at Shishou Tian-e-zhou Reserve and 4 free-ranging individuals at Tianxingzhou were recorded using a broadband digital recording system with four element hydrophones. The peak-to-peak apparent source level (ASL_pp) of clicks from individuals at the Baiji aquarium was 167 dB re 1 μPa with mean center frequency of 133 kHz, -3dB bandwidth of 18 kHz and -10 dB duration of 58 μs. The ASL_pp of clicks from individuals at the Shishou Tian-e-zhou Reserve was 180 dB re 1 μPa with mean center frequency of 128 kHz, -3dB bandwidth of 20 kHz and -10 dB duration of 39 μs. The ASL_pp of clicks from individuals at Tianxingzhou was 176 dB re 1 μPa with mean center frequency of 129 kHz, -3dB bandwidth of 15 kHz and -10 dB duration of 48 μs. Differences between the source parameters of clicks among the three groups of finless porpoises suggest these animals adapt to their echolocation signals depending on their surroundings.

Coherence experiments in single-pixel digital holography

In optical scanning holography (OSH), the coherence properties of the acquired holograms depend on the single-pixel size, i.e., the active area of the photodetector. For the first time, to the best of our knowledge, we have demonstrated coherent, partial coherent, and incoherent three-dimensional (3D) imaging by experiment in such a single-pixel digital holographic recording system. We have found, for the incoherent mode of OSH, in which the detector of the largest active area is applied, the 3D location of a diffusely reflecting object can be successfully retrieved without speckle noise. For the partial coherent mode employing a smaller pixel size of the detector, significant speckles and randomly distributed bright spots appear among the reconstructed images. For the coherent mode of OSH when the size of the pixel is vanishingly small, the bright spots disappear. However, the speckle remains and the signal-to-noise ratio is low.

Structure of butt joint of as-cast magnesium alloys

The article presents a structural analysis of joints of as-cast magnesium alloys created using three joining methods: friction stir welding, CO2 laser welding and electric arc welding in inert gas shielding using tungsten electrode (TIG). The macro- and microstructures of the butt joints have been evaluated using an optical microscope with a digital image recording system. Two types of magnesium alloys were used in the research: AZ91 and AM-Lite, the main alloying elements of which are zinc and aluminium. The starting material consisted of cast ingots milled to a specific dimension and then cut into plate samples with a thickness of 3 mm. The subsequent analysis showed that it is possible to achieve high-quality joints of magnesium alloys. However, trace quantities of pores have also been found.

Whither the future of internet streaming and time-shifting? Revisiting the rights of reproduction and communication to the public in copyright law after Aereo

New forms of communication technology often pose challenges to the copyright regime and have necessitated the rewriting of the scope of the exclusive rights and exceptions by the legislature, and, in some cases, by the courts in common law countries (as well as the Court of Justice of the European Union). These issues have arisen in different categories of digital technology, albeit with the same objective of streamlining and simplifying the delivery of copyright works to consumers. These categories include file storage and transfer operations offered by Peer-to-Peer technology, the space- and time-shifting functions of the early video and audio recording products, user-generated and industry content deliverable via new media streaming platforms, the ‘live’ streaming and time-shifting services offered by remote and wireless digital recording systems, file storage and sharing digital lockers and cloud technology. This article will examine the legality of Internet streaming and time-shifting technologies under copyright law, specifically in relation to the rights of ‘reproduction’ and ‘communication to the public’, through a comparative analysis of the jurisprudence in leading jurisdictions in recent times. Although the decisions are not always consistent, they do provide some helpful guidance in our assessment of the relative strengths and weaknesses of the various arguments made on both sides of the divide as well as of the prevailing judicial sentiment towards new technologies. In light of the continuing legal uncertainty faced by such technologies, the authors also offer suggestions as regards legislative amendments and alternative business models to ensure their continued existence in this harsh and highly competitive digital environment.