The Dynamics of Coupled Oscillators

<p>The subject is introduced by considering the treatment of oscillators in Mathematics from the simple Poincar´e oscillator, a single variable dynamical process defined on a circle, to the oscillatory dynamics of systems of differential equations. Some models of real oscillator systems are considered. Noise processes are included in the dynamics of the system. Coupling between oscillators is investigated both in terms of analytical systems and as coupled oscillator models. It is seen that driven oscillators can be used as a model of 2 coupled oscillators in 2 and 3 dimensions due to the dependence of the dynamics on the phase difference of the oscillators. This means that the dynamics are easily able to be modelled by a 1D or 2D map. The analysis of N coupled oscillator systems is also described. The human cardiovascular system is studied as an example of a coupled oscillator system. The heart oscillator system is described by a system of delay differential equations and the dynamics characterised. The mechanics of the coupling with the respiration is described. In particular the model of the heart oscillator includes the baroreceptor reflex with time delay whereby the aortic fluid pressure influences the heart rate and the peripheral resistance. Respiration is modelled as forcing the heart oscillator system. Locking zones caused by respiratory sinus arrhythmia (RSA), the synchronisation of the heart with respiration, are found by plotting the rotation number against respiration frequency. These are seen to be relatively narrow for typical physiological parameters and only occur for low ratios of heart rate to respiration frequency. Plots of the diastolic pressure and heart interval in terms of respiration phase parameterised by respiration frequency illustrate the dynamics of synchronisation in the human cardiovascular system.</p>

The Dynamics of Coupled Oscillators

<p>The subject is introduced by considering the treatment of oscillators in Mathematics from the simple Poincar´e oscillator, a single variable dynamical process defined on a circle, to the oscillatory dynamics of systems of differential equations. Some models of real oscillator systems are considered. Noise processes are included in the dynamics of the system. Coupling between oscillators is investigated both in terms of analytical systems and as coupled oscillator models. It is seen that driven oscillators can be used as a model of 2 coupled oscillators in 2 and 3 dimensions due to the dependence of the dynamics on the phase difference of the oscillators. This means that the dynamics are easily able to be modelled by a 1D or 2D map. The analysis of N coupled oscillator systems is also described. The human cardiovascular system is studied as an example of a coupled oscillator system. The heart oscillator system is described by a system of delay differential equations and the dynamics characterised. The mechanics of the coupling with the respiration is described. In particular the model of the heart oscillator includes the baroreceptor reflex with time delay whereby the aortic fluid pressure influences the heart rate and the peripheral resistance. Respiration is modelled as forcing the heart oscillator system. Locking zones caused by respiratory sinus arrhythmia (RSA), the synchronisation of the heart with respiration, are found by plotting the rotation number against respiration frequency. These are seen to be relatively narrow for typical physiological parameters and only occur for low ratios of heart rate to respiration frequency. Plots of the diastolic pressure and heart interval in terms of respiration phase parameterised by respiration frequency illustrate the dynamics of synchronisation in the human cardiovascular system.</p>

Influence of respiration frequency on heart rate variability parameters: A randomized cross-sectional study

BACKGROUND: Many patients visiting physiotherapists for musculoskeletal disorders face psychosocial challenges which may form a large barrier to recover. There are only a limited number of evidence based psychosocial therapies, but they are mainly based on breathing exercises. OBJECTIVE: to study which respiration frequency would lead to the highest relaxation, reflected in vagal tone derived from the heart rate variability (HRV) in healthy subjects. METHODS: A randomized controlled cross sectional study was performed. Respiration cycles of four, five, six, seven and eight breaths per minute (BPM) were delivered in randomized order for two minutes each. HRV metrics were measured during the sessions with electrocardiogram (ECG). Repeated Measures ANOVA’s were performed to analyze differences between breathing frequencies. RESULTS: 100 healthy volunteers were included (40 male). Standard Deviation of inter beat intervals (SDNN) values were significantly highest at 5 BPM, whereas the Root Mean Square of Successive Differences (RMSSD) values appeared highest at 7 breaths per minute (p< 0.01). High Frequency (HF) power was lowest at 4 BPM, whereas Low Frequency (LF) power was not significantly influenced by respiration frequency. CONCLUSIONS: Breathing at a frequency of 5 to 7 breaths per minute leads to highest HRV values, but there is no single respiration ratio that maximizes all metrics. Physiotherapists may use five to seven BPM as guidance to determine ideal breathing frequencies.

PENGARUH MANIPULASI IKLIM KANDANG MELALUI PENGKABUTAN TERHADAP RESPON FISIOLOGIS DAN KETAHANAN PANAS KAMBING SAPERA DAN PERANAKAN ETTAWA

This study aimed to determine the effect of cage microclimate manipulation with misting on physiological responses and heat resistance of goats (Sapera and Ettawa Grade). This research was conducted in April - May 2020 at Telaga Rizki People's Farm, Metro City, Lampung Province. This study used an experimental method, Split Plot design with a completely randomized design (CRD). This study used two treatments, namely modification of the pen consisting of pens without misting (K0) and pens with misting (K1) and two breed of goats, namely Sapera and Ettawa Grade (PE) goats. Each treatment was carried out 3 times. Goats as subplots and microclimate modification of the pen as the main plot. In this study, twelve female goats were used, namely 6 Sapera goats and 6 Ettawa Grade (PE) goats aged 2-3 years. The parameters observed were microclimate condition, namely air temperature, relative humidity (RH), and Temperature Humidity Index (THI), and physiological responses including rectal temperature, respiration frequency, heart rate frequency, and heat tolerance (HTC). The results of the research showed that there was significant effect (P<0.05) of treatments on RH and THI. The resilts also showed that there was no significant effect (P>0.05) of treatments on rectal temperature, heart rate, respiration frequency, HTC and environment temperature. Keywords : Misting, Pens microclimate, Physiological responses

Meniup Super Bubbles dan Baling-Baling Bamboo pada Anak Penderita Pneumonia

This study aims to determine the effect of blowing superbubbles and blowing bamboo propellers on children's respiratory frequency with pneumonia. The study design was pre-test and post-test two groups. The results of the univariate analysis before the blow therapy were carried out. Super bubbles, the respiratory frequency of all respondents was included in the moderate category, namely 10 (100%) respondents. After the intervention, there was a change to the mild type, namely as many as 3 (30%) respondents. Whereas before the therapy of blowing bamboo propellers, the respiratory frequency of the majority of respondents was included in the medium category, namely as many as 8 (80%) of respondents, and after therapy, the respiration frequency was balanced between the moderate and light types, namely as many as 50% of respondents respectively. The bivariate analysis results showed the effect of blowing superbubbles and blowing bamboo propellers on the respiratory frequency of the children with a p-value of 0.000, and 0.006, respectively. In conclusion, the intervention of blowing superbubbles and blowing propeller affects the respiratory frequency of children with pneumonia. Keywords: Baling-Baling Bamboo, Respiratory Frequency, Blow Super Bubbles

Model Estimasi Suhu Kritis Atas pada Sapi Perah Dara Berdasarkan Manajemen Pakan

A research was conducted in Jakarta and Bogor and during January 2014 until February 2014. The objective of research were to measure effects of critical temperature (air temperature and humidity) on indicate physiological responses for critical temperature of Fries Holland Heifer.They were fed twice daily with grass and concentrate. Six dairy heifers were used in the research. The Indicate physiological responses were heart rate and respiration frequency for 14 days. The results show that critical temperature on physiogical responses were significantly better on cattle for ANN which for critical temperature in Jakarta and Bogor that with the same and significantly better too on cattle which respiration frequency and heart rate in Jakarta and Bogor.

Prognostic Value of Three Rapid Scoring Scales and Combined Score for the Assessment of Patients with Coronavirus Disease 2019

Background: Severe coronavirus disease 2019 (COVID-19) is associated with high mortality, whereas mild cases generally have a good prognosis. Therefore, the rapid assessment and timely classification of patients with COVID-19-related pneumonia are very important. However, no scoring system has been designated for the rapid assessment and prognosis of patients with COVID-19. Such a system is urgently needed. Objective: To explore the factors affecting mortality in patients with COVID-19 and to verify if the predictive value of the three rapid scoring scales [the Modified Early Warning Score (MEWS), Rapid Acute Physiology Score (RAPS) and Rapid Emergency Medicine Score (REMS)] that are commonly used in emergency departments can also be used for the prognostication of COVID-19 patients. Methods: The study included adult patients diagnosed with COVID-19 in Wuhan, China from February 7 to March 7, 2020. Kaplan–Meier and Cox survival analyses were performed to identify the risk factors associated with COVID-19-related death. C-index analysis was used to evaluate the abilities of the three scoring scales and their combined score to predict the prognosis of COVID-19 patients. Results: Older age, decreased lymphocyte count, increased respiration frequency, and low blood oxygen saturation level were identified as independent risk factors for mortality among patients with COVID-19. The Cox regression analysis demonstrated that MEWS, RAPS, and REMS had a statistically significant ability to predict mortality in COVID-19 patients (P < 0.05). Stats the C-index of MEWS, RAPS, REMS, and the combined score resulted 0.7,0.66, 0.82, and 0.83 respectively. Conclusion: Patients with an old age, increased respiration frequency, low blood oxygen saturation level, and decreased lymphocyte count are at a high risk of COVID-19-related mortality. Moreover, our analysis revealed that the REMS had a better prognostic ability than the MEWS and RAPS when applied to COVID-19 patients. Our findings suggest that the REMS can be used as a rapid scoring tool for the early assessment of COVID-19 severity.

Emotion, Respiration, and Heart Rate Variability: A Mathematical Model and Simulation Analyses

Although the generation mechanism of the low-frequency (LF) component of heart rate variability (HRV) is controversial, HRV is a potential candidate in designing objective measurement methodologies for emotions. These methodologies could be valuable for several biosignal applications. Here, we have conducted a simulation analysis using a novel mathematical model that integrates emotion, respiration, the nervous system, and the cardiovascular system. Our model has well reproduced experimental results, specifically concerning HRV with respiratory sinus arrhythmia and LF, the relation between HRV total power and the respiration frequency, and the homeostatic maintenance by the baroreflex. Our model indicates the following possibilities: (i) The delay in the heart rate control process of the parasympathetic activity works as a low-pass filter and the HRV total power decreases with a higher respiration frequency; (ii) the LF component of HRV and the Mayer wave are generated as transient responses of the baroreflex feedback control to perturbations induced by an emotional stimulus; and (iii) concentration on breathing to reduce the respiration frequency can reduce LF/HF and the reduction can be fed back to the emotional status.