Beat Frequency Research Articles

Studying the variability of fluorescence emission and the presence of clumpy wind in HMXB GX 301−2 using XMM–Newton

ABSTRACT We present the results from an analysis of data from an XMM–Newton observation of the accreting high-mass X-ray binary pulsar GX 301−2. Spectral analysis in the non-flaring segment of the observation revealed that the equivalent width of the iron fluorescence emission is correlated with the observed absorption column density and the ratio of the iron Kβ and Kα line strength varied with the flux of the source. Coherent pulsations were detected with the spin period of the pulsar of 687.9 ± 0.1 s, and a secondary pulsation was also detected with a period of 671.8 ± 0.2 s, most prominent in the energy band of the iron line. At the spin period of the neutron star, the pulsation of the iron line has a low amplitude and the profile is different from the continuum. Pulse phase-resolved spectroscopy also revealed pulsations of the iron emission line during the non-flaring segment of the light curve. At the secondary period, both the iron line and the continuum have nearly identical pulse fraction and pulse profile. The additional periodicity can be attributed to the beat frequency between the spin of the neutron star and the Keplerian frequency of a stellar wind clump in retrograde motion around the neutron star. Reprocessed X-ray emissions originating from the clump can produce the observed secondary pulsations both in the continuum and the iron fluorescence line. The clump rotating around the neutron star is estimated to be approximately five lt-s away from the neutron star.

The hydrodynamics and kinematics of the appendicularian tail underpin peristaltic pumping.

Planktonic organisms feed while suspended in water using various hydrodynamic pumping strategies. Appendicularians are a unique group of plankton that use their tail to pump water over mucous mesh filters to concentrate food particles. As ubiquitous and often abundant members of planktonic ecosystems, they play a major role in oceanic food webs. Yet, we lack a complete understanding of the fluid flow that underpins their filtration. Using high-speed, high-resolution video and micro particle image velocimetry, we describe the kinematics and hydrodynamics of the tail in Oikopleura dioica in filtering and free-swimming postures. We show that sinusoidal waves of the tail generate peristaltic pumping within the tail chamber with fluid moving parallel to the tail when filtering. We find that the tail contacts attachment points along the tail chamber during each beat cycle, serving to seal the tail chamber and drive pumping. When we tested how the pump performs across environmentally relevant temperatures, we found that the amplitude of the tail was invariant but tail beat frequency increased threefold across three temperature treatments (5°C, 15°C and 25°C). Investigation into this unique pumping mechanism gives insight into the ecological success of appendicularians and provides inspiration for novel pump designs.

ODAD1 variants resulting from splice-site mutations retain partial function and cause primary ciliary dyskinesia with outer dynein arm defects.

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder caused by defects in motile ciliary function and/or structure. Outer dynein arm docking complex subunit 1 (ODAD1) is an important component of the outer dynein arm docking complex (ODA-DC). To date, 13 likely pathogenic mutations of ODAD1 have been reported. However, the pathogenesis of ODAD1 mutations remains elusive. To investigate the pathogenesis of splice-site mutations in ODAD1 discovered in this study and those reported previously, molecular and functional analyses were performed. Whole-exome sequencing revealed a compound mutation in ODAD1 (c.71-2A>C; c.598-2A>C) in a patient with PCD, with c.598-2A>C being a novel mutation that resulted in two mutant transcripts. The compound mutation in ODAD1 (c.71-2A>C; c.598-2A>C) led to aberrant splicing that resulted in the absence of the wild-type ODAD1 and defects of the outer dynein arm in ciliary axonemes, causing a decrease in ciliary beat frequency. Furthermore, we demonstrated that the truncated proteins resulting from splice-site mutations in ODAD1 could retain partial function and inhibit the interaction between wild-type ODAD1 and ODAD3. The results of this study expand the mutational and clinical spectrum of PCD, provide more evidence for genetic counseling, and offer new insights into gene-based therapeutic strategies for PCD.

The Role of Soluble Adenylyl Cyclase in the Regulation of Flagellar Motility in Ascidian Sperm.

Flagellar motility in sperm is activated and regulated by factors related to the eggs at fertilization. In the ascidian Ciona intestinalis, a sulfated steroid called the SAAF (sperm activating and attracting factor) induces both sperm motility activation and chemotaxis. Cyclic AMP (cAMP) is one of the most important intracellular factors in the sperm signaling pathway. Adenylyl cyclase (AC) is the key enzyme that synthesizes cAMP at the onset of the signaling pathway in all cellular functions. We previously reported that both transmembrane AC (tmAC) and soluble AC (sAC) play important roles in sperm motility in Ciona. The tmAC plays a major role in the SAAF-induced activation of sperm motility. On the other hand, sAC is involved in the regulation of flagellar beat frequency and the Ca2+-dependent chemotactic movement of sperm. In this study, we focused on the role of sAC in the regulation of flagellar motility in Ciona sperm chemotaxis. The immunochemical analysis revealed that several isoforms of sAC protein were expressed in Ciona sperm, as reported in mammals and sea urchins. We demonstrated that sAC inhibition caused strong and transient asymmetrization during the chemotactic turn, and then sperm failed to turn toward the SAAF. In addition, real-time Ca2+ imaging in sperm flagella revealed that sAC inhibition induced an excessive and prolonged Ca2+ influx to flagella. These results indicate that sAC plays a key role in sperm chemotaxis by regulating the clearance of [Ca2+]i and by modulating Ca2+-dependent flagellar waveform conversion.

High‐accuracy optical delay measurement based on linear frequency sweeping technology

AbstractA high‐accuracy and wide‐range optical delay measurement method based on linear frequency modulation (LFM) of a microwave source is proposed, which can measure the delay of each channel in a parallel multichannel interference structure. The light wave emitted by the light source is injected into the dual‐parallel Mach‒Zehnder modulator (DPMZM) as a carrier wave. The LFM microwave signal is loaded into the radio frequency ports of the DPMZM through a 90° hybrid couple, and the bias voltages of the DPMZM are adjusted to make it work in carrier suppression single sideband (CS‐SSB) modulation mode. The CS‐SSB optical signal output by the modulator enters the test links, including a Mach‒Zehnder interference loop composed of the reference arm and the device under test arm. Then, the output optical signal of the interference loop is input into a photodetector, and the intermediate frequency (IF) signals are obtained by the beat frequency. The frequency of the IF signal is obtained through data acquisition and fast Fourier transform calculation. Thus, the delay time is calculated. By increasing or decreasing the LFM signal scanning time, the delay measurement range can be extended, or the measurement accuracy over a short distance can be improved. The feasibility of this method is verified by experiments, and the delay of parallel multichannel measurement is carried out.

The relationship among acceleration, metabolism, and tail beat frequency of channel catfish (Ictalurus punctatus) during critical swimming speed tests

Accelerometers collect real-time, high-resolution data over extended time periods providing insight into behavior, movement, and physiology of free-swimming animals in captive or natural environments. In aquaculture settings, acceleration can also be used as a proxy for metabolism, providing useful information to inform bioenergetic models and indices of fish welfare. However, defining the acceleration-metabolic relationship for species of interest is a critical first step before information can be applied. Because catfish aquaculture has a large economic impact in the USA, examining the use of acceleration as a proxy for continuous measures of metabolism could prove beneficial. Here, accelerometers were used in channel catfish (Ictalurus punctatus) to examine the relationship between acceleration as measured by overall dynamic body acceleration (ODBA) and metabolism as measured by oxygen consumption (MO2), and how these variables changed with increasing water velocity during critical swimming speed tests. Tail beat frequency was used to validate ODBA measurements. There was a clear relationship between ODBA and water velocity, and metabolism and water velocity, with ODBA increasing 3.2-fold and metabolism increasing 2-fold as water velocity increased. Tail beat frequency also increased 1.5-fold with each increase in water velocity, validating our acceleration results. There was also a clear relationship between ODBA and metabolism, with metabolism increasing 1.1-fold as the ODBA values increased. Results in this study show accelerometers can act as a proxy for metabolic measures in channel catfish and provide the basis for further applications in bioenergetics or operational welfare to benefit the aquaculture industry.

Measuring Biophysical Properties of Cilia Motility from Mammalian Tissues via Quantitative Video Analysis Methods.

Ciliated epithelia are common in various human organs, indeed across many species, and their physiological functions are vital. A number of diseases, of genetic, degenerative, or infectious nature, compromise motile cilia function and lead to severe downstream consequences. Culture of ciliated tissues is a common research approach. We focus here on the video microscopy and analysis pipelines developed over the last few years to phenotype ciliary beating in lung cells, specifically to extract: cilia coverage; ciliary beat frequency distributions; the scale for ciliary dynamical coordination; and cilia beat waveform.

Structural Analysis of Sperm Centrioles Using N-STORM.

A prominent technical barrier when imaging swimming sperm is capturing a singular sperm cell's head and tail position simultaneously at a high resolution to understand their relationship in different stages of the sperm tail beating cycle. This is due to the sperm's high beating frequency, rotational movement, and the large difference in diameter between the head and tail. These intricacies increase the complexity of determining the position of a dynamic subcellular structure in the sperm neck, such as the centriole. We have developed a way to obtain this information by snap freezing mobile sperm at different stages of the sperm tail beating cycle and then analyzing them with super-resolution microscopy. This method captures the position of both the sperm head and tail at the microscale and centriolar substructure details at the nanoscale. This chapter describes the detailed procedures for the selection, preparation, antibody staining, 3D N-STORM imaging, and image quantification of bovine spermatozoa.

High-Speed Video Microscopy of Ependymal Cilia in Brain Organotypic and Cell Culture Models.

The wall of the ventricular system within the neuraxis is lined almost entirely by E1 ependymal cells, each of which projects multiple motile cilia from their apical surface into the cerebrospinal fluid (CSF). This specialized layer of E1 cells constitutes the border between the CSF and the brain interstitial fluid (BIF), and by controlling influx and efflux across the CSF to BIF interface, it is increasingly recognized to play an integral role in modulating and maintaining the brain microenvironment. The motile cilia have been shown to be responsive to changes in the CSF microenvironment, and while the physiological role of this mechanism remains incompletely understood, manipulating this control mechanism may influence the brain microenvironment potentially opening a new frontier in therapeutic intervention.In this paper, we describe our techniques for preparing organotypic slices from the murine brain parenchyma and establishing cell cultures of multiciliated ependymal cells from mouse and rat neonatal brain tissue. Our methodology generates a functional readout of ciliary function, specifically high-speed video microscopy (HSVM) enables the quantification of ciliary beat frequency (CBF), and characterization of ciliary beat pattern.

BPIFB1 loss alters airway mucus properties and diminishes mucociliary clearance.

Airway mucociliary clearance (MCC) is required for host defense and is often diminished in chronic lung diseases. Effective clearance depends upon coordinated actions of the airway epithelium and a mobile mucus layer. Dysregulation of the primary secreted airway mucin proteins, MUC5B and MUC5AC, is associated with a reduction in the rate of MCC; however, how other secreted proteins impact the integrity of the mucus layer and MCC remains unclear. We previously identified the gene Bpifb1/Lplunc1 as a regulator of airway MUC5B protein levels using genetic approaches. Here, we show that BPIFB1 is required for effective MCC in vivo using Bpifb1 knockout (KO) mice. Reduced MCC in Bpifb1 KO mice occurred in the absence of defects in epithelial ion transport or reduced ciliary beat frequency. Loss of BPIFB1 in vivo and in vitro altered biophysical and biochemical properties of mucus that have been previously linked to impaired MCC. Finally, we detected colocalization of BPIFB1 and MUC5B in secretory granules in mice and the protein mesh of secreted mucus in human airway epithelia cultures. Collectively, our findings demonstrate that BPIFB1 is an important component of the mucociliary apparatus in mice and a key component of the mucus protein network.NEW & NOTEWORTHY BPIFB1, also known as LPLUNC1, was found to regulate mucociliary clearance (MCC), a key aspect of host defense in the airway. Loss of this protein was also associated with altered biophysical and biochemical properties of mucus that have been previously linked to impaired MCC.

Linear polarization and narrow-linewidth external-cavity semiconductor laser based on birefringent Bragg grating optical feedback

We demonstrate an external-cavity semiconductor laser (ECSL) with linear polarization and a narrow linewidth. A birefringent Bragg grating prepared by a femtosecond laser point-by-point technique in a polarization-maintaining fiber (PMF) is used to provide external-cavity feedback, and its polarization-dependent characteristics enable selection of the main polarization mode and linewidth narrowing of the ridge waveguide emission gain chip (GC). This compact and robust ECSL achieves an output power of > 60 mW and a polarization extinction ratio (PER) of > 30 dB. We simulate and calculate the linewidth and injection current, while a Lorentz linewidth of 2.58 kHz is obtained based on delayed self-heterodyne beat frequency measurement. This flexible and cost-effective solution allows realization of a compact ECSL with linear polarization and a narrow linewidth.

Numerical study on the influence of centroid‐to‐buoyancy center ratio on the motion stability of supercavitating vehicle

SummaryIn order to study and solve the influence of the change of the position of the centroid of the supercavitating vehicle on the motion stability, the influence law of the position of the centroid of the supercavitating vehicle on the motion stability is found, and the quantitative criterion that can guide the design of the supercavitating vehicle is summarized. On the basis of theoretical analysis, the dynamic mesh technology combined with the volume of fluid multiphase flow model and the rigid body six degrees of freedom motion calculation model is used to carry out the supercavitating vehicle motion and supercavitating flow field coupling numerical simulation research for supercavitating vehicles with different cavitator shapes. The results show that the position relationship between the centroid position and the buoyancy position has a great influence on the motion stability of the vehicle. When the center of buoyancy is before the center of mass, the vehicle is unstable; when the center of buoyancy is behind the center of mass, the vehicle sails stably, and when the position of buoyancy action coincides with the center of mass, the amplitude of the tail beat of the vehicle is the smallest, and the navigation is the most stable, which is the best position of the centroid. In this article, the concept of centroid‐to‐buoyancy center ratio is proposed. The so‐called centroid‐to‐buoyancy center ratio refers to the ratio of the length from the centroid to the top of the head of the supercavitating vehicle to the length from the center of buoyancy to the top of the head of the vehicle. When the centroid‐to‐buoyancy center ratio fluctuates in the range of [0.8–1], it is an ideal condition for the stable navigation of the vehicle. When the centroid‐to‐buoyancy center ratio is in the range of (0, 0.8), the tail beat frequency is high, which accelerates the kinetic energy consumption and the rapid instability of the vehicle. Therefore, under the same constraint conditions, it is not that the closer the center of mass is, the better the stability of the vehicle motion is. The optimal centroid position is not a certain “point,” but a “periodic fluctuation interval” that changes with the buoyancy center.

Nonreciprocal double-carrier frequency combs in cavity magnonics

We propose a scheme for realizing strongly nonreciprocal double-carrier frequency combs in three-mode cavity magnonic system consisting of two microwave cavities and a yttrium iron garnet sphere with magnon Kerr nonlinearity. The nonreciprocal microwave frequency comb (MWFC) and magnonic frequency comb (MFC) can be simultaneously implemented due to the asymmetrical nonlinear response in two different directions. We first show high tunability of nonreciprocal MWFC and MFC based on independent sideband in the situation of single input probe field. By properly operating the input fields, the perfect nonreciprocity of comb in a broad frequency range (nonreciprocity of number of comb) and ultrahigh isolation ratio (nonreciprocity of intensity of comb) are obtained. We prove that the tooth spacing of frequency comb can be flexibly modulated by adjusting the beat frequency between the probe field and the control field, the fraction-order comb thereby is generated, which unlocks the full potential for producing high resolution frequency comb. More importantly, it is find that the sideband mixing emerges for the situation of double input probe fields. The hybridized MWFC and the hybridized MFC further are formed, which enhances greatly nonreciprocity of fraction-order comb. These consequently give rise to the simultaneous achievement of high resolution and strong nonreciprocity of double-carrier frequency combs. Our proposal provides an effective avenue for the manipulation of the nonreciprocity and resolution of MWFC and MFC, and has potentially practical applications in precision measurement and integrated quantum technology.

Feeding Behavior Responses of the Small Copepod, Paracalanus parvus, to Toxic Algae at Different Concentrations.

The feeding relationship between copepods and phytoplankton has immense ecological significance. This study investigated the feeding behavior of copepods by studying the feeding selectivity of Paracalanus parvus, a key small copepod species, using a high-speed camera. The feeding behavior of P. parvus separately fed on three algae, Prorocentrum minimum, Alexandrium minutum, and Thalassiosira weissflogii, was studied at five different concentrations. The factors characterizing feeding behavior, including the beating frequency (BF), beating time (BT), and rejection behavior, were analyzed. The average BT and BF of P. parvus fed on toxic algae were significantly lower than those of copepods fed on nontoxic algae, indicating that the toxic algae negatively affected their feeding behavior. There were no significant differences in feed rejection among the three algae during the short period of experimentation, indicating that the rejection behavior was insignificant in the early period (within 20 min) of feeding on toxic algae. The feeding behavior was inhibited when the concentration reached 250 cells/mL. The BT was initially affected at increasing concentrations followed by the BF, and P. minimum and A. minutum reduced the BF at concentrations of 250 and 1000 cells/mL, respectively. Analysis of the average BFs revealed that P. parvus was more significantly affected by P. minimum containing diarrheal shellfish poison than by A. minutum containing paralytic shellfish poison. The BF of copepods fed on P. minimum was significantly lower than that of copepods fed on A. minutum at 250-500 cells/mL but was not significantly different from that at 1000 cells/mL. This indicated that the inhibitory effect of P. minimum on the feeding behavior was more significant at concentrations observed at the onset of red tide blooms (0.25-0.5 × 102 cells/mL), but insignificant at concentrations reaching those in advanced red tides (>103 cells/mL). This study demonstrates that toxic dinoflagellates alter the feeding behavior of copepods and describes the variations in their feeding response to different algal species and concentrations. The findings provide crucial insights for further studies on the feeding relationship between copepods and phytoplankton and on functional assessment of plankton ecosystems.

Novel nasal formulation of xylometazoline with hyaluronic acid: In vitro ciliary beat frequency study

Acute viral rhinosinusitis (viral ARS), or commonly referred to as the “common cold”, is caused by respiratory viruses that cause disruption of the airway epithelial barrier and mucociliary dysfunction. Treatment of ARS is mainly symptomatic, with xylometazoline, a direct-acting α-adrenoceptor agonist, commonly used as a nasal decongestant. Unfortunately, this treatment does not resolve the epithelial dysfunction observed in ARS, and its use might negatively impact the nasal mucosa causing issues such as dryness, stinging, burning, rebound congestion, as well as atrophy. In light of this, a novel nasal spray formulation containing both xylometazoline and hyaluronic acid (HA) was developed to provide a more effective and safer treatment for viral ARS. HA is a natural polysaccharide known to hydrate and moisturise the upper respiratory tract, maintain the integrity of the nasal mucosa, and promote mucociliary clearance and wound healing. To investigate the potential of this combination, this study was conducted using the nasal MucilAirTMin vitro model and high-speed phase-contrast microscopy to examine the effect of xylometazoline and HA on ciliary function by measuring ciliary beat frequency and their cytotoxicity by morphological, histological and ultrastructural analysis. This research is the first to assess the effects of a specific dose and molecular weight of HA as an active pharmaceutical ingredient in nasal spray formulations. The combination of a fast-acting decongestant and an additional active agent targeting nasal epithelial dysfunction has the potential to provide an improved, reliable and safe treatment for viral ARS, and may serve as the basis for future clinical studies.

Design of a novel high-frequency link broadband inverter based on beat frequency principle

As a kind of special power supply for testing, the broadband inverter has relatively high research value for technological innovation. With the goal of broadband output, this paper proposes a novel high-frequency link inverter topology based on the beat frequency and LCC resonance. Firstly, the working principle is studied. Then, aiming at large circulation problems in the beat frequency modulation process, the method of the series-connected four-coupling reactor is adopted. Finally, experimental results show that this novel inverter can realize broadband output from 20Hz to 1010Hz with voltage THD not exceeding 3% and the relative frequency error between setting and actual is within 0.2%. The whole work proves that this novel inverter has characteristics of broadband output, high-frequency link, current mode, and soft switching.

Aerodynamic sound production from flying beetles

Extensions of previous research on the aerodynamic sound production by flying beetles are presented. The topic is of interest in terms of both fundamental acoustics and the applications such as classification and tracking of invasive insect species. High speed video with synchronous acoustics recordings of the Coconut Rhinoceros Beetle (Oryctes rhinoceros) and the Oriental Flower Beetle (Protaetia orientalis) provide experimental data for the analytical and numerical models. Three dimensional, unsteady flow simulations were conducted using compressible flow software (CAESIM, Adaptive Research, Inc.) with a TVD methodology. Flapping wing motion requires mesh deformation with a rotation with a prescribed bending and also coupled rotation and translation of the wing’s hinge position. Contributions of wing beat frequency and vorticity to sound generation are examined with respect assumptions of the spatial dimensions (two or three dimensional), bending and fluid structure interactions. Underlying sound generation mechanisms at the wing tips are examined in higher fidelity. Both hovering and forward flight are investigated and compared in terms of the different flapping motion of the two species. In addition, relationships of the tones to the temporal lift and drag lift coefficients are highlighted.

Interpolation time-optimized aortic pulse wave velocity estimation by 4D flow MRI

Four-dimensional flow magnetic resonance imaging-based pulse wave velocity (4D flow PWV) estimation is a promising tool for measuring regional aortic stiffness for non-invasive cardiovascular disease screening. However, the effect of variations in the shape of flow waveforms on 4D flow PWV measurements remains unclear. In this study, 4D flow PWV values were compared using cross-correlation algorithm with different interpolation times (iTs) based on flow rate and beat frequency. A critical iT (iTCrit) was proposed from in vitro study using flexible and stiff phantom models to simultaneously achieve a low difference and a low computation time. In vivo 4D flow PWV values from six healthy volunteers were also compared between iTCrit and the conventionally used interpolation time of 1 ms (iT1 ms). The results indicated that iTCrit reduced the mean difference of in vitro 4D flow PWV values by 19%, compared to iT1 ms. In addition, iTCrit measured in vivo 4D flow PWV, showing differences similar to those obtained with iT1 ms. A difference estimation model was proposed to retrospectively estimate potential differences of 4D flow PWV using known values of PWV and the used iT. This study would be helpful for understanding the differences of PWV generated by physiological changes and time step of obtained flow waveforms.

Experimental evaluation of the nonselective and selective TMEM16 family calcium-activated chloride channel blockers in the airways

Abstract Background The family of calcium-activated chloride channels, TMEM16, plays a significant role in contributing to the pathogenesis of airway inflammatory diseases. Targeting these ion channels and aiming to modulate them may provide an interesting new approach to the therapy of these potentially fatal diseases. Methods We tested this hypothesis in both healthy and ovalbumin (OVA)-sensitized male Dunkin-Hartley guinea pigs. The ion channel activity was modulated by TMEM16A-nonselective (benzbromarone) and TMEM16A-selective blockers (CaCCinh-A01). In vivo airway reactivity, induced by histamine and methacholine, was expressed as specific airway resistance (sRaw) values. The number of citric acid-induced coughs was counted using a double-chambered body plethysmograph, and the frequency of ciliary beating (CBF) was assessed in vitro by brushing method. For comparison, salbutamol and codeine were tested under the same conditions. Results The results showed significant differences in the responses of unsensitized and sensitized airways to both TMEM16 blockers administered. CaCCinh-A01 and benzbromarone significantly reduced the number of cough efforts in the group of OVA-sensitized guinea pigs. Significant improvement in sRaw values could be observed in OVA-sensitized TMEM16 blocker–treated animals compared to salbutamol when challenged with inhalational histamine, and the outcome was similar to salbutamol when challenged with methacholine. CBF was significantly inhibited in animals sensitized to OVA treated with selective inhibition of TMEM16A. Conclusions The results demonstrated that treatment with blockers of TMEM16 can reduce both cough effort and sRaw, and the difference between TMEM16A-selective and TMEM16A-nonselective blocking is only negligibly in favor of CaCCinh-A01. It is also worthwhile to note the impairment of CBF in OVA-sensitized animals treated with CaCCinh-A01.

Under the sea: How can we use heart rate and accelerometers to remotely assess fish welfare in salmon aquaculture?

Recent advances in bio-sensing technologies open for new possibilities to monitor and safeguard the welfare of fishes in aquaculture. Yet before taken into practice, the applicability of all novel biosensors must be validated, and the breadth of their potential uses must be investigated. Here, we investigated how ECG and accelerometry-derived parameters measured using bio-loggers, such as heart rate, acceleration and variance of acceleration, relate to O2 consumption rate (MO2) and blood borne indicators of stress and tissue damage to determine how biologgers may be used to estimate stress and welfare. To do this, we instrumented 13 fish with a biologger and an intravascular catheter and subjected them to a swimming protocol followed by a stress protocol throughout which the physiological parameters were measured and analyzed a posteriori. Additionally, based on the empirical data obtained, we calculated the mathematical relationships between the bio-logger data and the other parameters and tested the relationship between the calculated parameters using the linear regression algorithms and the measured parameters. Our results show that acceleration is a good proxy for swimming activity as it is closely related to tail beat frequency. In addition, we show that heart rate, acceleration and variance of acceleration all can be used as predictors for metabolic rate. Accelerometry based data, especially variance of acceleration, significantly explain some of the variation in venous partial pressure of O2, blood lactate and plasma cortisol concentration. Variance of acceleration also significantly explains some of the variation in pH and mean corpuscular hemoglobin concentration. These relationships are explained by variance of acceleration being a good indicator of the onset of burst-swimming activity, which is often followed by acid-base imbalances and release of catecholamines. The results herein indicate that bio-logger data can be used to extrapolate a range of stress-related physiological events when these are accompanied by increases in activity and highlight the great potential of biosensors for monitoring fish welfare.