Study of well‐being of older adults, a rapidly growing demographic group in sub‐Saharan Africa, depends on well‐validated tools like the WHOQOL‐OLD. This scale has been tested on different populations with reasonable validity results but has limited application in Africa. The specific goal of this paper was to examine the factor structure of the WHOQOL‐OLD translated into three Ghanaian languages: Ga, Akan, and Kasem. We also tested group invariance for sex and for type of community (distinguished by ethnicity/language).We interviewed 353 older adults aged 60 years and above, selected from three ethnically and linguistically different communities. Using a cross‐sectional design, we used purpose and convenience methods to select participants in three geographically and ethnically distinct communities. Each community was made up of selected rural, peri‐urban, and urban communities in Ghana. The questionnaire was translated into three languages and administered to each respondent.The results showed moderate to high internal consistency coefficient and factorial validity for the scale. Using confirmatory factor analysis, we found that the results supported a multidimensional structure of the WHOQOL‐OLD and that it did not differ for males and females, neither did it differ for different ethnic/linguistic groups.We conclude that the translated versions of the measure are adequate tools for evaluation of quality of life of older adults among the respective ethnic groups studied in Ghana. These results will also enable comparison of quality of life between older adults in Ghana and in other cultures. The need for a validated measure is important for cross‐cultural studies of well‐being. In a study among older adults in a sub‐Saharan African country, we found that the WHOQoL‐OLD measure is an adequate tool for evaluation of quality of life. We did not find group invariance suggesting comparability of quality of life across different ethnicities. The WHOQOL_OLD has factorial validity in a cross‐cultural context.Translation into multiple languages does not affect the factor structure.There are no differences in sex on the issue of quality of life.It appears death and dying is an uncomfortable subject among older adults.1The rapid pace of economic development in low‐ and middle‐income countries (LMICs) has resulted in demographic shifts from younger populations to a more aged population. This is fueled largely by improved health care and increase in life expectancy in many LMICs Ahmad, . ImproveIn LMICs, especially in sub‐Saharan African countries like Ghana, the research is gradually shifting from physical health needs research to quality of life and mental health research, but this change is slow and therefore limited information is available on psychological health needs of the older adults  we tested the assumption that the underlying dimensions of the measure would be confirmed, and we also examined whether (2) the WHOQOL‐OLD is invariant for males and females and (3) invariant for three ethno‐linguistic groups.It was our expectation that the use of the WHOQOL‐OLD among Ghanaians will yield a concise evaluation of older people's rating of their quality of life and furthermore provide caregivers, healthcare providers, and potentially policy makers with a more holistic idea of what older people need in order to have quality of life.22.1The sample for this study was selected using a multi‐stage process that began with selection of districts and then households. Three districts were purposively selected: Accra (Ga West district) in the south, Sunyani (Sunyani East and West districts) in the middle belt, and Navrongo in the Upper East Region. Three factors guided the selection of the districts. First, the districts are geographically and ethnically distinct, and they have easily accessible rural, peri‐urban, and urban communities. Second, their locations in the South, Middle, and the Northern‐most parts of the country ensured that the sample for the study was close to a nationally representative sample. Third, all three districts had their unique languages which then allowed us to examine the factorial validity of the quality of life scale in ethno‐linguistically different groups. The selected ethnic groups are three of the six major ethnic groups in Ghana. Each selected district has a dominant language although other languages may be spoken within the districts.The criteria for inclusion were that the participants had to be 60 years and above and did not have any signs of ill‐health that could impede their ability to participate in the interview. In each selected district, a community facilitator who lives in and knows the community very well was hired to help stratify the communities in the districts in order to select participants from all different sections of the selected district. In each selected locality, any household with an individual who was 60 years and older was contacted. The distribution of the sample is presented in Table 2.2The World Health Organization Quality of Life‐Old (WHOQOL‐OLD) is a 24‐item, 6‐facet instrument with cross‐cultural reliability . SecondThe third step involved the evaluation of the back‐translated versions, comparing them to the original WHOQOL‐OLD by the first author who is literate in Akan and Ga languages. In the case of Kasem, the back‐translated version was evaluated with one of the research assistants. During this phase, the first author corrected any discrepancies, focusing on contextual and linguistic meaning. Items that lacked clarity were referred to the translators. The final phase involved a discussion of contextual and linguistic equivalence of the items during training. The first author who did the training led the discussion on the items, and when there was no consensus, the item(s) was referred to the translators.2.4Eight research assistants were trained for the study; five had degrees in psychology, one had a degree in sociology, one had a degree in social work, and one had a degree in education. The training of research assistants was in two phases. The first phase involved training on the original English version. In the second phase, the research assistants were trained on the translated versions of the questionnaire. During this phase, the research assistants and the first author had discussions about contextual and linguistic accuracy and items on which there was no consensus were referred to the translators.We pretested the questionnaire in a sample of 25 older adults in a peri‐urban town in the northern part of Accra. This is a typical Ghanaian community which shared similar characteristics with the communities for the main study. There were minimal modifications to item translations following feedback from the participants. For example, one item on the Death and Dying dimension—“Fear pain before death”—was deleted after multiple translations could not result in consensus on meaning of the item.All participants completed the WHOQOL‐OLD scale and a demographic questionnaire that included questions about age, marital status, living arrangements, occupational, and income statuses. We administered the questionnaire in the dominant language for each district. Interviews were conducted by trained interviewers (research assistants) with the use of the questionnaire as described in measures.2.5The research received ethical approval from the Ethical Committee for Humanities of the University of Ghana. The study number is ECH 105/17‐18. The research was done in compliance with ethical requirements in Ghana. All participants signed or thumb‐printed an informed consent form. Participants received either phone credits or cakes of soap valued at five Ghana cedis (approximately $1.00).2.6The questionnaires were coded into SPSS Version 24. The data were managed and analyzed using this software. The Cronbach's alpha coefficients were estimated to assess internal consistency. A series of confirmatory factor analysis (CFA) was also conducted to test for the theorized model and factorial structure and to test for group invariance.3The descriptive statistics of background characteristics of the study sample are presented in Table Majority of the respondents were females (67.2%), and the average age was 71.65 years. Almost two‐thirds of the respondents were not married or lived with a regular partner. More than 70% were not employed or on a regular income which is expected of the demographic group studied.Internal consistency was measured using the Cronbach alpha coefficient, and they were all found to be reasonably acceptable ranging from 0.844 to 0.937 for the WHOQOL domains. These are considered moderate to high coefficients Cortina, . Death aThe correlation analysis showed there were moderate correlations among the WHOQOL subdimensions. The correlation with death and dying was the lowest. The results for correlations are presented in Table 3.12; Δχ2) were used. A nonsignificant Δχ2 and ΔCFI ≥ −0.01 between the restrictive and less restrictive or unconstrained models indicate the attainment of sex invariance. Regional invariance determination followed the procedure above.Confirmatory factor analysis (CFA) was used to estimate the factor structure of the WHOQOL in the full sample. This was followed by multi‐group CFA to determine measurement invariance of the WHOQOL based on sex and geographical location. In the first of series of analyses, separate models were estimated for males and females, followed by estimation of unconstrained (baseline) model. In this model, the parameters were freely estimated across the groups, with satisfactory fit indices indicating the attainment of a configural invariance. In subsequent model estimations, some constraints were introduced, with each successive model containing all the constraints of its predecessor. First, the factor loadings were held constant across the groups to investigate metric invariance, followed by covariance and variances, and lastly error variances were held to be equal for the groups to determine invariance of the covariance and variances, and error variances, respectively. To determine sex invariance, differences in comparative fit index  and chi‐square , and a noncentrality‐based index, the root mean square error of approximation (RMSEA). The CFA and multi‐group CFA were conducted with maximum likelihood estimation method in Analysis of Moment Structures (AMOS) version 21 . A decision was reached to exclude the Death and Dying dimension from further analysis.Preliminary analysis in the CFA revealed that the model did not provide a good fit to the data . Inspection of the items constituting the various dimensions of the scale showed that the items for Death and Dying loaded poorly  and were not significant , providing a good model fit .The CFA and sex invariance analysis results are summarized in Table Sex specific analyses also revealed that the models in which the residuals of the aforementioned items correlate freely showed significant model improvement over the initial models. The results of sex invariance analyses based on the respecified models indicate that configural invariance , metric invariance (ΔCFI = 0.00), and invariance of factor variance (ΔCFI = 0.00) and (ΔCFI = −0.01) have been attained. The factor structure from the CFA model and their corresponding coefficients are summarized in the Figure 3.3Feel a sense of companionship in life) and Intimacy item #22 (Experience love in your life) (MI = 25.09), and sensory abilities items #22 (rate of sensory functioning) and #23 (Loss of sensory abilities affect participation in activities) (MI = 15.55). As can be seen, the resulting models were good fit to the data . The initial models for participants from Accra and Sunyani were respecified based on the modifications above, leading to an improvement in model fit. For Accra, the fit of the respecified model is as follows: . In addition to the above, the model for participants from Navrongo was respecified by allowing the residuals of items for Social interaction items #22 (Satisfied with level of activity) and #23 (Satisfied with opportunity to participate in community); and Autonomy items #2 (Feel in control of your future) and #4 (Able to do things you'd like) to correlate freely. The resulting model improved over the initial model and provided a good model fit to the data . Measurement invariance analyses also revealed that configural invariance , metric invariance (ΔCFI = 0.00), and invariance of factor variance (ΔCFI = 0.00) and error variances (ΔCFI = −0.01) have been attained.Table 4The primary aim of this paper is to establish the factorial validity of the 24‐item WHOQOL for older adults on three selected samples from Ghana. Our overarching research question was, therefore, whether or not the WHOQOL‐OLD can be used as a reliable and valid instrument for measuring quality of life among individuals living in three geographically and linguistically different districts in Ghana. This measure has been translated into over 15 languages and within those contexts provided a good basis for the measurement of quality of life among older adults . In general, the findings of the study have revealed that quality of life among adults in Ghana can be represented by the dimensions stipulated by the WHOQOL‐OLD. More importantly, the multidimensional structure of the WHOQOL‐OLD is invariant across sex and three different ethnic and linguistic groups. This finding lends support to previous studies that have used the WHOQOL‐OLD in different countries, including in South Africa  that exert influence on behaviors, the study has largely re‐echoed the notion that the experience and endorsement of quality of life as a salient psychosocial construct can be similar, in accordance with the concept of universality of certain behavioral repertoires (Adjorlolo et al., A cross‐cultural measure proven to have sound psychometric properties will be useful in studying quality of life and mental health needs and to provide the opportunity for comparative analysis in Ghanaian contexts and across other LMICs.5There are a number of limitations that need to be considered when interpreting the results from this study. Social desirability and other biases may influence participants’ response to the study measures. This possibility is heightened because self‐report measures primarily do not provide mechanisms to ascertain the accuracy of participants’ response, compared with task‐based assessment modalities. The sample size for each district selected for this study was slightly less than optimal. Estimating sample size for structural equation modeling depends on a number of factors such as number of indicators, number of factors, magnitude of factor loadings, and magnitude of factor correlations (Wolf et al., It should be noted that the structure of the WHOQOL‐OLD was confirmed in the Ghanaian sample following model modifications based on the modification indices. This partly raises concerns about the stability of the structure of the WHOQOL‐OLD‐R in a similar sample. The findings of this and previous studies suggest there are problems with the WHOQOL‐OLD dimension “Death and Dying” providing inadequate model fit (Chachamovich et al., 6This study adds to the growing number of studies that have shown that the WHOQOL_OLD has cross‐cultural validity. However, the finding that the death and dying dimension did not measure the construct adequately provides impetus for additional studies on the underlying factor structure of the WHOQOL‐OLD in the Ghanaian population or similar populations. Given that death and dying is a major theme for the aged, future research in Ghana or on a similar population should consider reconceptualizing the items to align with Ghanaian cultural perspectives on death and dying. For example, Van der Geest, in a series of studies among rural populations, has found that Ghanaians make reference to and preference for “good death,” dying peacefully and naturally in one's old age (Van der Geest, The authors report no conflict of interest.All authors have given consent for publication.


Background: This paper presents a soft sensor design technique for the estimation of pitch and yaw angular positions of a Twin Rotor MIMO System (TRMS). The objective of the proposed work was to calculate the value of pitch and yaw angular positions using a stochastic estimation technique. Methods: Measurements from optical sensors were used to measure fan blade rotations per minute (RPM).  The Kalman filter, which is a stochastic estimator, was used in the proposed system and its results were compared with those of the Luenberger observer and neural network. The Twin Rotor MIMO System is a nonlinear system with significant cross-coupling between its rotors. Results: The estimators were designed for the decoupled system and were applied in real life to the coupled TRMS. The convergence of estimation to the actual values was checked on a practical setup. The Kalman filter estimators were evaluated for various inputs and disturbances, and the results were corroborated in real-time. Conclusion:  From the proposed work it was seen that the Kalman filter had at least Integral Absolute Error (IAE), Integral Square Error (ISE), Integral Time Absolute Error (ITAE) as compared to the neural network and the Luenberger based observer. IAE: Integral Absolute ErrorISE: Integral Square ErrorITAE: Integral Time Absolute ErrorMIMO: Multi-Input Multi-OutputTRMS: Twin Rotor MIMO System The TRMS position is controlled by the rotor speed. The two input variables to the TRMS are voltage to the main rotor and tail rotor, and the outputs are the pitch and yaw angle as shown inThe study of aerospace systems has always been a subject of interest by many researchers, engineers, and technical students. However, it is practically very difficult to analyze these aerospace systems, so a replica is designed to understand the behavior of the actual systems. One such system, which replicates the behavior of a helicopter system, is a TRMS. The TRMS has two of the three movements of a helicopter, pitch angle, and yaw angle., But building a model based on the first principle approach is a very tedious task, hence the mathematical models are always preferred based on measured data. In some cases, the structure of the model is predefined, but rigorous algorithms are applied to estimate the parameters of the model. The estimation is done based on algorithms like genetic algorithm, particle swarm optimization, recursive least squares, artificial neural network, and evolving fuzzy modeling. Quasi-Linear parameter varying modeling and feedforward neural network are also used for system identification of TRMS.Modeling of the real-time TRMS system is a key step carried out for the execution of control action or any other estimation in presence of noise. Physical models are either based on Newtonian or Lagrangian concepts. Rahideh and Shaheed discussed the design of a model predictive controller for a TRMS. The controller is simulated based on the state model using motor armature current and angular speed as inputs. Jahed and Farrokhi discussed the design of a fuzzy-based robust control for a TRMS using angular speed given by a tachometer in a simulation platform, and Taoet al. discussed the fuzzy sliding and integral sliding controller design for a TRMS. In Rohith, a new control law was proposed for the design of sliding motor controllers, which mitigate the chattering problem with the gain variation and thereby guarantees faster system response and robustness. The design of an auto-tuning based PID controller with fractional-order reference model approximation for a DC rotor in a TRMS model is discussed in Alagozet al. The data regarding the process variable is derived from the angular position of pitch and yaw.Several researchers have reported work on computing the yaw and pitch positions using different techniques. Different algorithms are incorporated to maintain and retain the stability of the TRMS. Controllers like Proportional Integral Derivative (PID), fuzzy PID, sliding mode controller, fuzzy sliding mode controllers, and estimators like Luenberger and Kalman are incorporated on the TRMS. a tuning method based on the Moore Skelboe Algorithm for a PID controller was presented. This was effective in finding the optimal PID values for the given initial range and applicable for some of the higher-order Linear Time-Invariant (LTI) systems as well as for all first and second-order linear time-invariant systems. Further, the method was effective in stabilizing unstable systems. Halim and Ismail presented a PID controller tuning using tree physiology optimization, which was based on the tree growth concept whose simulation results showed better results compared to other tuning methods in Single Input Single Output (SISO) and MIMO problems. Raoet al., reported design of an observer using robust PID controller logic withH∞ observer to obtain the stable output in TRMS with sensor and actuator failure. Nettoet al., reported an Adaptive PID controller to cancel the effect of cross-coupling between the tail rotor and main rotor when operating simultaneously in a TRMS. Adaptive linear quadratic regulator design for stable system operating at a single reference point with six tail and main rotors is reported by Faisal and Omar Waleed. Ghellabet al., reported an adaptive radial basis function neural network with a dynamic terminal sliding mode control with cross-coupling between the tail and main subsystem for tracking the set point in the presence of wind gust and other external disturbance.In Patel and Janardhanan,et al. a linear time-varying controller was designed using a differential flatness property leading to a two Degree of Freedom (DOF) controller for which the system must be in canonical controllable form with no need to define its dynamics. In Pandaet al., the proposed control strategy used an adaptive backstepping controller implemented on a Twin Rotor Multi Input Multi Output System. It provided an explicit relationship between the saturation bound of the input signal and upper bounds of tracking errors, uncertainties, and disturbances. Mondal and Dey presented the development of a two DOF control system design providing an additional degree of freedom depending on the nature of the plant and loop compensators. The design methodology can be implemented for integer as well as non-integer order plants with better tracking and loop robustness.In Sleimiet al. The design of a differential evolution-based neural network model to control the TRMS with data of angular positions was reported by Subudhi and Jena. Pratap and Purwar, reported the implementation of a neuro-adaptive robust backstepping controller for TRMS.Neural network-based controller design using model inversion control for a twin-rotor MIMO system was reported in Rahidehet al., Sun and Song and Ahmadet al. It was found that the system was a nonlinear and coupled one with considerable error in the measurements. The method based on the Kalman filter is considered as it provides for updating the estimates based on errors, and also takes into account the process and the measurement noise uncertainties to give out the best estimate. Model dynamics of the system are known and are used for estimation. The Kalman filter is widely used as a state estimator and is used in various fields.The TRMS dynamics are given in Rahidehet al., 2019 authors have proposed and designed an adaptive fuzzy low-pass filter-based L1 adaptive controller and implemented it on a TRMS. The main ideology behind the proposed work is to adapt the low pass filter, when the system is subjected to unknown disturbances, cancel them accordingly, and also provide efficient tracking performance. A control technology mainly intended to address the regulator problem by considering the uncertainties in TRMS motion control is proposed in. The proposed work is a cascaded control technology wherein nominal state and input trajectories are obtained in the first phase followed by obtaining a linearized model for tracking the reference yaw and pitch angles in the second phase.In MaitiThe TRMS is a prototype device used to understand the dynamics of a helicopter system. It consists of two rotor fans to operate the device in two Degrees of Freedom (2-DoF). For controlling/stabilizing the system performance based on the desired set point, it is essential to sense the actual pitch and yaw positions. The presence of faults during data transmission to the controller leads to the controller failing to take the desired action and thus the system destabilizes. Hence, a technique is proposed to design an estimator so that it can be used in case of any contingencies.The present work attempts to estimate the yaw and pitch angle of the TRMS in presence of sensor faults. To achieve this target, a data-driven model of TRMS is developed in presence of no disturbance and faults. Models are developed with measured data of yaw and pitch in the system identification toolbox of MATLAB. The toolbox employs a non-linear least square algorithm to estimate the parameters (coefficient s) of the transfer function (TF). The Kalman filter and Luenberger observer are based on data-driven mathematical models. The soft sensing techniques can be stochastic or deterministic. The Kalman filter is a stochastic sensing technique where there is no certainty in the reproducibility of the output for a given input. The Luenberger observer is based on a deterministic approach, where for a particular input always there is the same output. The neural network is developed based on input and output data; the trained model is deterministic.The sensor failure condition is artificially created during the operation of the TRMS and the performance of these soft sensing techniques is compared for the selection of the better one. The outline of the work carried out is shown inThe twin-rotor MIMO system is a prototype of a helicopter propeller system. It is shown inMaxon A-max motor of 18V,6W,30 mA, graphite brushed DC motors are used for the tail and main rotors with a maximum speed of 8300 RPM. The communication between the computer and TRMS system is established by PCI 1711 Multi-purpose Input/output card. It has sixteen channel single-ended analog inputs,12-Bit ADC with a 100 kHz sampling rate. To communicate with the computer, it has 16-channel digital input and output. The estimators are designed in the Simulink environment of MATLAB, PCI 1711 card helps to receive and transfer data between MATLAB and TRMS.The TRMS has two modes of operation, namely, 1-DOF control and 2-DOF control. In 1-DOF control, the pitch and the yaw are controlled individually and independently, whereas in 2-DOF control the pitch and the yaw are controlled simultaneously in a coupled system. The block diagram of the proposed scheme is shown in– Over time, it has been used as a state estimator also. It is a stochastic estimator and requires explicit modeling of the process noise and the measurement noise in addition to the system model. The Kalman filter estimation is a two-step process. Initially, it generates an estimate from the knowledge of the system dynamics, which is embedded in the system model along with the noise model. This is called the apriori estimate. Once the measurement output is available, the apriori estimate is updated to the posteriori estimate. The second stage involves the Kalman gain which is altered in every step based on an optimization problem.The Kalman filter is developed from the Bayesian filter. It was initially used to extract the signal from the noisy output data of sensors, and/or actuators.U and the process noiseW, as given inThe Kalman gain was the main feature of this estimator and it decided if the estimate derived much of its information from the measurement output or the system dynamics. Hence, the Kalman gain was also updated on every step such that the error between the actual output and the estimate was reduced i.e. the residue reduced to zero. The noise covariance matrix was also updated at each step based on the error. Here the Markovian model was used where the state was said to be Markovian but the measurement was usually not Markovian. Also, we considered the process noise and measurement noise as Gaussian, and they were not correlated with each other. It is also called the Gauss-Markov model. This allows nonlinearity. The mean was assumed to be zero for both measurement and process noises. Covariance was chosen in this case such that the covariance of measurement noise was slightly less than the covariance of the process noise. In general, the probability distribution of the state is given byFor the considered TRMS, the matrices for the decoupled pitch model were found to be:The matrices for the decoupled yaw model were found to be:V as inThe measurement obtained was modeled as a linear combination of the system states and measurement noiseS i.e.Q andR be processed noise covariance and measurement noise covariance respectively. The apriori error covarianceP is given byIn the TRMS model, the measured output i.e. pitch and yaw were related to states directly through output matricesOnce the measurement was obtained, the Kalman gain was computed and the apriori state estimates and the apriori error covariance were updated as follows:Kalman gain:The posteriori estimate:The posteriori error covariancek given the measurement atk and the apriori estimateXk at timek. Also, it should be noted that the Kalman filter was a one-step ahead predictor. The noise covariance matricesR andQ were the most complex matrices to compute, therefore the idea was to start with an initial estimate of identity matrices for bothR andQ and to change them based on the convergence between the actual and the estimated outputs. The Kalman filter estimated the states. However, the objective was to estimate the pitch and the yaw which were the output of the TRMS. Hence, the output was obtained fromHereError,The Kalman filter provided a stochastic method of estimation, whereas the Luenberger observer and neural network provided a deterministic method of estimation of the states. The estimation of yaw and pitch carried out with these deterministic methods had a poorer performance due to their inability to incorporate uncertainties that emerge inherently in any real systems, such as the uncertainties due to modeling errors or sensor output errors. However, these estimates can be feasible if the error margin is not very stringent. The extended Luenberger observer and adaptive Luenberger observer are the latest class of these observers. The Luenberger observer is used for estimation of battery charge for electric vehicles, flux in motor drives, motorcycle dynamics, sensor-less speed estimation. The scheme of this observer is shown inLuenberger based observers are widely used for numerous applications and modified according to the type of the system.Assume a plant:State equations of the observer:ex, would decay to zero. The design then consisted of solving for the values ofL to yield a desired characteristic equation.FromL. The poles for the observer for both pitch and yaw were chosen to be at −1, −2, and −3.Then the selection of eigenvalues for the observer was carried out to achieve a required closed-loop response. These eigenvalues determined a characteristic equation that was made equal toL for pitch was:The Luenberger gainL for yaw was:The Luenberger gainLevenberg-Marquardt algorithm with a back-propagation network having one hidden layer with a size of 10 neurons, which was used to predict the output i.e. the pitch and the yaw from the input. The neural network used for the present work is shown inMATLAB version R2014a, provided the platform to train the neural network and this was used in the current work.The estimation based on the neural network was based on a time-series correlation between the input and the output, also called the targets. This assumed a black body model, where the dynamics of the system were not explicitly parameterized and the forecasting was done only from the input-output relationship of the system. Here the neural network was trained to replicate the behavior of the system by using the given set of input-output pairs of data. TheA soft sensor for computing the yaw and pitch in TRMS using three different techniques, a neural network, a Kalman filter, and a Luenberger observer, was designed. The regression graph for the trained neural network is shown inThe efficacy of different techniques adopted is tested in the real scenario. Tests were conducted by applying input and disturbance. The response of the proposed sensing system using the Luenberger observer is represented inTwin rotor multi-input systems are fundamental elements for any aerial system, analysis of its performance is very much essential to further modify the system for better efficiency. The TRMS contains a motor system along with a sensor system for testing. Sensors are an integral part of the TRMS for providing actual information to the controller. Failure of the sensors would lead to errors in control action and thus lead to system failure.The reported work attempted to design an observer-based system, which would function accurately even with sensor faults. Sensor data is an essential input for any controller, erroneous sensor data would cause the controller to produce erroneous results. An estimator is designed using Kalman filter, Luenberger observer, and neural network model to predict the sensor output based on the secondary data of the TRMS system. The effectiveness of the Kalman filter algorithm for estimation of pitch and yaw angular positions was verified in real life on the TRMS with external disturbances. The estimate was updated at every sampling time to predict the yaw and pitch for angular positions for the given input and measurement data. The performance of the Kalman filter was compared with that of the neural network and Luenberger observer. From the results of IAE, ISE, and ITAE, the error was least when using the Kalman filter followed by the Luenberger observer, and lastly, the neural network. Hence, the estimation by the Kalman filter was more accurate during both transient and steady states.In the study, the work is carried out considering the system dynamics for given environmental conditions. External influence is not considered in the present work and in future work we would like to consider the same. Optimization of the estimator can also be achieved in future work.https://doi.org/10.17605/OSF.IO/VY8SA.Open Science Framework: Extended data for ‘Design of a soft sensing technique for measuring pitch and yaw angular positions for a Twin Rotor MIMO System’,•Supplementary Video 1: Experimental model of a soft sensor design technique for estimation of pitch and yaw angular positions of a Twin Rotor MIMO System (TRMS)•Supplementary Data 1: Simulink file used to carry out the real-time experimentation of TRMS system.This project contains the following extended data:Creative Commons Zero “No rights reserved” data waiver (CC0 1.0 Public domain dedication).Data are available under the terms of The revised version is much improved in terms of presentation and content. It may be considered for indexing.Is the work clearly and accurately presented and does it cite the current literature?YesIf applicable, is the statistical analysis and its interpretation appropriate?PartlyAre all the source data underlying the results available to ensure full reproducibility?YesIs the study design appropriate and is the work technically sound?YesAre the conclusions drawn adequately supported by the results?PartlyAre sufficient details of methods and analysis provided to allow replication by others?YesReviewer Expertise:Solar energy, Energy modelling, Energy systemsI confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. Thanks for the author's reply and for submitting the new version. Based on the new version, I confirm that I have no further comments to make.Is the work clearly and accurately presented and does it cite the current literature?PartlyIf applicable, is the statistical analysis and its interpretation appropriate?Not applicableAre all the source data underlying the results available to ensure full reproducibility?YesIs the study design appropriate and is the work technically sound?YesAre the conclusions drawn adequately supported by the results?YesAre sufficient details of methods and analysis provided to allow replication by others?PartlyReviewer Expertise:Control, system identification, mechatronics systems, automotiveI confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. et al., have carried out a study of soft sensing technique for measuring pitch and yaw angular positions for a Twin Rotor MIMO System. The research result is interesting. However some suggestions are provided to improve the quality and presentation of the study:Please maintain consistency in the use of Terminologies. For instance , is it MIMO or MIMI?Some sentences are difficult to read or incomplete . Sentence structure and rephrasing is needed.Provide list of Abbreviations: TRMS, MIMO, MIMI IAE, ISE, and ITAE.Instead of Comparative graphs, it may be mentioned as Comparative results.Distinguish the various soft sensing technique in terms of the stochastic methods? Which among the studied are stochastic and deterministic?based system, Kalman filteralgorithm and gain, and neural networkmodel using Levenberg-Marquardt algorithm and gain.The Luenberger observerThe various gain values and the noise covariance may be compared in a tabular format.The transient, steady states, 1-DOF control and 2-DOF control may be explained a bit clearly in the methodology and results section.Please provide the technical details of the TRMS containing the Twin Rotor motor system and the sensor system.The neural network regression model results for both pitch and yaw control may be introduced under the results section.What is the major contribution of this study? The soft sensing technique designed and tested for the senor motor by the authors is useful for other applications? Please elaborate on those aspects.What are the major limitations and future scope of the study.The conclusion lacks significant numbers to support the major outcome of the study.List down the key conclusion on the various numerical values obtained from the study.NayakIs the work clearly and accurately presented and does it cite the current literature?YesIf applicable, is the statistical analysis and its interpretation appropriate?PartlyAre all the source data underlying the results available to ensure full reproducibility?YesIs the study design appropriate and is the work technically sound?YesAre the conclusions drawn adequately supported by the results?PartlyAre sufficient details of methods and analysis provided to allow replication by others?YesReviewer Expertise:Solar energy, Energy modelling, Energy systemsI confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. Reviewer 2:Please maintain consistency in the use of Terminologies. For instance, is it MIMO or MIMI?  Response: Sorry for the mistake, we have consistently used MIMO, in the revised article.Some sentences are difficult to read or incomplete . Sentence structure and rephrasing are needed.  Response: Sorry for the mistake, the sentence is rephrased.Provide a list of Abbreviations: TRMS, MIMO, MIMI IAE, ISE, and ITAE.  Response: As suggested a table for abbreviation is provided.Instead of Comparative graphs, it may be mentioned as Comparative results. Response: As suggested the comparative graphs is changed to comparative resultsDistinguish the various soft sensing technique in terms of the stochastic methods? Which among the studied are stochastic and deterministic?  Response: As suggested we have added details about the sensing technique.The Luenberger observer-based system, Kalman filter algorithm and gain, and neural network model using Levenberg-Marquardt algorithm and gain. The various gain values and the noise covariance may be compared in a tabular format. Response: As suggested a comparative analysis of various system gains is provided in the revised version.The transient, steady states, 1-DOF control, and 2-DOF control may be explained a bit clearer in the methodology and results section.  Response: As suggested details are presented in the results sectionPlease provide the technical details of the TRMS containing the Twin Rotor motor system and the sensor system.  Response: Thank you for the suggestion, we have included details of the TRMS.The neural network regression model results for both pitch and yaw control may be introduced under the results section.  Response: As suggested results of both pitch and yaw are moved to results sections.What is the major contribution of this study? The soft sensing technique designed and tested for the senor motor by the authors is useful for other applications? Please elaborate on those aspects. Response: As suggested details are included in the conclusion.What are the major limitations and future scope of the study?Response: As suggested details are included in the conclusions.The conclusion lacks significant numbers to support the major outcome of the study.  Response: As suggested, outcomes are included in the conclusionList down the key conclusion on the various numerical values obtained from the study.Response: As suggested, numerical values are included in the conclusion. Comments: Nayak et al., have carried out a study of a soft sensing technique for measuring pitch and yaw angular positions for a Twin Rotor MIMO System. The research result is interesting. However, some suggestions are provided to improve the quality and presentation of the study: Contribution: The paper addresses the problem of estimation pitch and yaw angular positions of a Twin Rotor MIMO System (TRMS) using the soft-sensor technique. In particular, the authors propose an estimation to calculate the value of pitch and yaw angular positions using Kalman filter, Luenberger observer and neural network. More specifically, measurements from optical sensors were used to measure fan blade rotations per minute (RPM), and then Kalman filter estimators were evaluated for various inputs and disturbances. Finally, different experimental results have been presented to compare Kalman filter estimation with those of the Luenberger observer and neural network. The results show that the Kelman filter has the least IAE, ISE and ITAE as compared to the two other mentioned methods.General Evaluation: The submitted paper has some novelty in the field of soft sensing techniques using the Kelman filter approach for the Twin Rotor MIMO system. Although the paper suffers from a lack of deep analysis and comparison with other previous works, it is the reviewer opinion that the presented approach is of some interest since it provides an approach for estimating TRMS using Kalman filter in a comparison with Luenberger observer and neural network approach. All considered, it is my opinion that the paper deserves the merit to be considered for publication, provided that the comments reported below are properly taken into account by the authors.Comments: The paper in general is organized. However, the authors are invited to take into account the following comments in order to improve the quality of the contribution.et al. (2017), R. Maitiet al. (2018), S. Miahet al. (2019), etc. and to provide a discussion on the comparison between such works and the proposed approach.  1) It is my opinion that the literature review is not satisfactory. Although the authors mentioned some of the previous methods related to the topic, they didn't provide a full literature overview of the proposed problem and more specifically to model estimation of the TRMS system. The authors are advised to add e.g., the work of A. Tastemirov 2) It is not clear on which basis the poles for the observer for both pitch and yaw were chosen to be at -1, -2, and -3. The authors are advised to add more details about the chosen values and how these can affect the accuracy of the obtained model.y matrix is not clear, there should be spaces between each column.  3) The matrices for the decoupled pitch and yaw models in Equations 3 and 4 are exactly the same; which is strange. The authors are advised to re-check again the values and discuss more the founded model. Moreover, the S 4) R and Q matrices computation was missing or not well discussed. The authors are advised to explain more the procedure they used to compute R and Q and how this leads to equation 10.  5) An explanation of Fig. 2 is missing. The authors are advised to comprehensively discuss the outline of this paper. Furthermore, it suggested removing any literature that is out of the scope of the provided topic .  6) The authors stated the following "The estimator having the highest number of errors was not accurate" on page 11. However, it is not so clear and it is suggested to re-write it in a better way.Is the work clearly and accurately presented and does it cite the current literature?PartlyIf applicable, is the statistical analysis and its interpretation appropriate?Not applicableAre all the source data underlying the results available to ensure full reproducibility?YesIs the study design appropriate and is the work technically sound?YesAre the conclusions drawn adequately supported by the results?YesAre sufficient details of methods and analysis provided to allow replication by others?PartlyReviewer Expertise:Control, system identification, mechatronics systems, automotiveI confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. 1) It is my opinion that the literature review is not satisfactory. Although the authors mentioned some of the previous methods related to the topic, they didn't provide a full literature overview of the proposed problem and more specifically to model estimation of the TRMS system. The authors are advised to add e.g., the work of A. Tastemirov et al. (2017)1, R. Maiti et al. (2018)2, S. Miah et al. (2019)3, etc. and to provide a discussion on the comparison between such works and the proposed approach.Response: Thank you for the suggestion, we have included recent and relevant publications in the literature review. 2) It is not clear on which basis the poles for the observer for both pitch and yaw were chosen to be at -1, -2, and -3. The authors are advised to add more details about the chosen values and how these can affect the accuracy of the obtained model.Response: Any observer design aims to drive the error between the outputs of the plant and observer to zero. The error function is multiplied with the gain which enhances the convergence of the estimates to the true states. A high gain leads to fast convergence but too high causes a peaking phenomenon. By choosing the eigenvalues of the observer on the left half of the s-plane, the error dynamics can be controlled appropriately. For computation, poles are considered by multiplying by at least 10 times to the poles of the system. 3) The matrices for the decoupled pitch and yaw models in Equations 3 and 4 are exactly the same; which is strange. The authors are advised to re-check again the values and discuss more the founded model. Moreover, the Sy matrix is not clear, there should be spaces between each column.Response: The decoupled pitch model was found to be:Fp=-1.4389-3.1862 1.67060.0803-4.9874 -29.1821-0.0376 0.0474 -5.5737; Gp=100         Sp=0.0166  0.4194  2.454;  D=0  (3). The matrices for the decoupled yaw model were found to be:Fy=-1.38-1.6456-14.76110.9244-2.5724-31.1124-0.01960.3346-8.0476; Gy=100Sy=0.001  0.0336  0.4065;  D=0 (4).y is a 3x3 matrix, Gyis 3x1 and Sy is a 1x3 matrix. Both the equations were rechecked. Sorry for the representation, F 4) R and Q matrices computation was missing or not well discussed. The authors are advised to explain more the procedure they used to compute R and Q and how this leads to equation 10.Response: the noise covariance matrices R and Q are the most complex matrices to compute, therefore the idea is to start with an initial estimate of identity matrices for both R and Q and to change it based on the convergence between the actual and the estimated outputs. 5) An explanation of Fig. 2 is missing. The authors are advised to comprehensively discuss the outline of this paper. Furthermore, it suggested removing any literature that is out of the scope of the provided topic .Response: Thank you for the suggestion, we have added an explanation for Figure 2 and removed the literature as suggested. 6) The authors stated the following "The estimator having the highest number of errors was not accurate" on page 11. However, it is not so clear and it is suggested to re-write it in a better way.Response: Sorry for that, we have revised the paragraph so, as to prove improvement to the work.


Cardiac auscultation is an important screening test at the first health examination of puppies because most clinically relevant congenital cardiac anomalies cause a loud murmur from birth. This retrospective study aimed to investigate the age at which dogs with suspected congenital cardiac anomalies were referred to a veterinary cardiology specialist for murmur investigation. A secondary aim was to establish the time interval between the visit to the cardiologist and the first available murmur documentation. The digital archive of a veterinary teaching hospital was searched for dogs with congenital cardiac anomalies and puppies with innocent murmurs during a 5-year period. Dogs had to be referred because of a murmur, and they had to undergo physical examination and echocardiography by a veterinary cardiology specialist. The health certificate section of the pet passport, and the medical records from the referring veterinarian, were reviewed to identify the date when the murmur was first documented.Of the 271 included dogs, 94% had a congenital cardiac anomaly and 6% had an innocent murmur. The dogs’ median age was 190 days when they were examined by the cardiologist. Only 10% of the dogs were referred by the breeder’s veterinarian, while 90% of the dogs were referred by the new owner’s veterinarian. The median age of the first available murmur documentation by a first opinion veterinary practitioner was 95 days.Only 10% of the puppies in the present study were referred to a veterinary cardiology specialist for murmur investigation before they were sold to a new owner. Referral prior to re-homing would have been feasible if the murmur had been detected and documented by the breeder’s veterinarian, if referral was offered by the breeder’s veterinarian and the referral was accepted by the breeder. Most puppies with a congenital heart disease show no clinical signs of their heart disease when they are examined by a first opinion veterinary practitioner at the first veterinary health screening at about 6–8 weeks of age –11. The Of the three most prevalent congenital cardiac anomalies in dogs , both left-to-right shunting patent ductus arteriosus and severe pulmonic stenosis are effectively treatable conditions and they typically cause loud murmurs , 14–18. Several studies report diagnostic and therapeutic findings in adult dogs with congenital cardiac anomalies , 20, 21.®  recognized European veterinary specialist in small animal cardiology. An upper age limit of 10 months was applied in dogs with a non-pathological (innocent) murmur for inclusion [In this retrospective case series, the electronic database of a single academic veterinary teaching hospital was searched for puppies with an innocent murmur or all dogs with congenital cardiac anomalies, during a period of five years, between January 2014 and January 2019. Inclusion criteria were: (1) dogs had to be referred, either solely for a cardiac murmur or a cardiac murmur in combination with other problems, to the cardiology service of the authors’ institution; and (2) a physical examination followed by an echocardiographic examination had to be performed by an EBVSnclusion . No age All dogs underwent a thorough physical examination and an echocardiogram both performed by a veterinary cardiology specialist. The echocardiogram was carried out on unsedated animals restrained in right and left lateral recumbency, and the examination consisted of 2-dimensional, M-mode, color Doppler and spectral (pulsed- and continuous wave) Doppler studies from the standard left and right parasternal as well as subcostal views .An attempt was made to obtain the following information: (1) the age of the dog at the first documentation of the murmur in the health certificate section of the dog’s pet passport, (2) the age of the dog at the first documentation of the murmur in the medical record and/or in the referring letter of the referring veterinarian, (3) whether the dog was referred by the breeder’s or the new owner’s veterinarian, (4) the age of the dog at the visit to a non-cardiologist veterinarian for an echocardiographic examination (if this took place), (5) the age of the dog at the visit to the cardiology service of the authors’ institution, (6) the intensity of the murmur as described by the referring veterinarian, (7) the intensity of the murmur as described by the attending veterinary cardiology specialist, (8) the echocardiographic diagnosis made by the non-cardiologist, (9) the echocardiographic diagnosis made by the veterinary cardiology specialist, and (10) the presence or absence of clinical signs, as well as the leading clinical sign in case of symptomatic dogs as described by the owner. If a dog showed more than one clinical sign, it was classified only in a single category based on the following priority order: distended abdomen, dyspnea, syncope, cough, retarded growth, exercise intolerance and weight loss. For example, if a dog had dyspnea and exercise intolerance, the case was listed under dyspnea.The murmur intensity as recorded by the attending veterinary cardiology specialist on the day of the visit was compared with the historical recorded findings of the referring veterinarian. The auscultation findings of the referring veterinarian were identified in the medical records which were sent to the authors’ institution as part of the referring letter. The referring veterinarian was either the breeder’s veterinarian or the new owner’s veterinarian. The findings of the breeders’ veterinarians were obtained from the health certificate section in the pet passport, if this document was available, in case the puppy was referred by the new owner’s veterinarian. Pet passports in the country where the study took place contain a separate section about the health status of each organ, including the heart, which should be filled in by a first opinion veterinary practitioner at each time when a vaccination is given or before an animal travels abroad. Though completing this document is not obligatory, it is part of good veterinary practice. Moreover, this is the only written veterinary documentation that serves as a health certificate when a puppy is sold to the new owner.Based on the veterinary cardiology specialist’s echocardiographic diagnosis, the murmurs were classified as either pathologic or non-pathologic. Besides identifying the cause of the murmurs, the need and possibility for interventional/surgical correction of the defect were noted. The severity of obstructive anomalies  was classified based on the Doppler-derived pressure gradient in unsedated, awake animals as severe (higher than 80 mmHg), moderate (between 50 and 80 mmHg), or mild (between 16 and 49 mmHg) , 18, 23.The veterinary cardiology specialist’s final diagnosis was compared to the non-cardiologist’s echocardiographic diagnosis, if the dog had undergone an echocardiographic examination elsewhere before referral to the authors’ institution. The findings of the two veterinarians were classified as full agreement, partial agreement or disagreement based on therapeutic consequences. An example of full agreement is when both assessors diagnosed the same disorder with the same category of severity, even if the pressure gradient of an obstructive disorder differed markedly , but the difference did not affect the therapeutic advice, because in both cases balloon valvuloplasty would be advised. An example of a partial agreement is when the same defect was found by both examiners but the severity was different , even if the absolute difference was smaller than in the previous example. When the veterinary cardiology specialist found multiple congenital cardiac anomalies and the non-cardiologist detected only some of them, it was also marked as a partial agreement. However, if the natural history of the disease was assumed to lead to a different diagnosis  between the two examinations, then the case was marked as a full agreement. The degree of agreement between the different assessors was expressed in percentages.Descriptive statistical analysis was performed using commercial statistical software . The age of the dogs is presented in days as median and range. Correlation between murmur intensity and the age at referral was calculated using Pearson’s correlation coefficient. A correlation coefficient close to  +  1 or − 1 indicated positive or negative correlation, respectively, whereas a value close to 0 indicated no correlation.A total of 271 dogs fulfilled the inclusion criteria. The median age of the dogs when presented to the cardiology service of the authors’ institution for investigation of a cardiac murmur was 190 days   had a pathological murmur and 17 (6%) had a non-pathological (innocent) murmur. According to the owners, 182 dogs (67%) were clinically healthy, while 89 (33%) showed one or more clinical signs: exercise intolerance (n  =  28), syncope (n  =  18), dyspnea (n  =  16), cough (n  =  16), distended abdomen (n  =  7), retarded growth (n  =  3), and weight loss (n  =  1).Only three dogs with cardiac-related clinical signs resulting from severe congenital cardiac anomalies that were not referred solely or in part because of a murmur were identified in the study period. These dogs were excluded from the study population, as the murmur was detected at the authors’ clinic for the first time. One of these three dogs had severe tricuspid valve dysplasia, the second dog had severe mitral valve dysplasia and the third one had both a severe mitral and a severe tricuspid valve dysplasia.The 271 dogs were referred from 224 different veterinary practices. Written documentation about the presence of a murmur from a first opinion veterinary practitioner was available in 249 of the 271 dogs (92%). These 249 dogs’ median age was 95 days (3.2 months) at the first available murmur documentation. The source of this information was either the pet passport (when this was available) or the medical record of the referring veterinarian, recorded either by the breeder’s or new owner’s veterinarian. Inconsistences regarding the documented dates in the two types of documents are shown in Table Based on the referring veterinarians’ medical records only (n  =  264), the median age of the dogs when their murmur was first documented was 99 days . The delay between the first available murmur documentation and the visit to the cardiology specialist was 95 days .In only 50 of the 79 available pet passports (63%) was the presence of the cardiac murmur recorded. All passports were of Dutch origin. The median age when the murmur was first documented in these 50 dogs was 67 days . Whether the breeder’s or the new owner’s veterinarian documented the murmur is shown in Fig. Only 27 of the 271 dogs (10%) were investigated for their murmur at the cardiology service of the authors’ institution based on the referral from the breeder’s veterinarian. Of these dogs, the median age at the first available documentation of the murmur was 46 days (range 25–73 days) and the median age at referral was 52 days (range 25–109 days).The veterinary cardiology specialists diagnosed isolated congenital cardiac anomalies in 211 dogs  as the cause of the murmur   before the dog was referred to the authors’ institution. An agreement on the diagnosis was found in 65 of the 124 dogs (52%), a partial agreement in 15 (12%) and 44 (35%) dogs the non-cardiologist did not manage to reach a diagnosis or there was a disagreement. The median age of the dogs when the echocardiogram was performed by the non-cardiologist was 152 days  and the median age when the echocardiogram was performed by the veterinary cardiology specialist was 190 days . The median difference between the two echocardiograms was 38 days .In 95 of the 271 dogs (35%) the veterinary cardiology specialist recommended an intervention either to close a left-to-right shunting patent ductus arteriosus or to dilate a severe (or in selected cases a moderate) pulmonic stenosis. In 62 of the 95 dogs (65%), the owners agreed to perform cardiac intervention, which is 23% of all enrolled dogs. All procedures were performed at the authors’ institution.The age of referral in these 95 dogs showed no correlation with the murmur intensity either. The correlation coefficient was − 0.12 when the murmur intensities of the cardiologists were used, and it was − 0.27 when the murmur intensities of the referring veterinarians were used for the analysis.A left-to-right shunting patent ductus arteriosus was closed in 27 dogs, with trans-catheter embolization being used in 25 dogs and via thoracotomy in 2 dogs. The median age of these 27 dogs at the time of surgery was 115 days , and the median age when their defect was diagnosed at the authors’ institution was 104 days . The time interval between the diagnosis and therapy for an average dog was 11 days.In 35 dogs a balloon valvuloplasty of a severe (or moderate) pulmonic stenosis was performed. The median age of these 35 dogs when they underwent a balloon valvuloplasty was 199 days , and the median age when their pulmonic stenosis was diagnosed at the authors’ institution was 145 days . The time interval between the diagnosis and balloon valvuloplasty for an average dog with pulmonic stenosis was 54 days.One of the most important findings of the present study is that only 10% of the 271 dogs, in which the referring veterinarian suspected a congenital cardiac anomaly based on the presence of a cardiac murmur, were referred to a veterinary cardiology specialist before the dog was sold to a new owner. The remaining dogs were referred by the new owner’s veterinarian. Whether the breeders had informed the new owners about the presence of a cardiac murmur was not investigated. Because the cardiac murmur of most clinically relevant congenital cardiac anomalies are audible from birth, diagnosing congenital cardiac anomalies should be possible when the puppy is still in the breeder’s possession . This tuIn the country where the study took place, the health certificate section in the pet passport is the only veterinary documentation available for new owners when they buy a puppy from a breeder. Pathological murmurs caused by congenital cardiac anomalies should have been present in every dog at the first health screening, which should be routinely carried out by the breeder’s veterinarian at 6 weeks of age, coinciding with the first vaccination. In the present case series, however, only 25% of the available health certificates of the pet passports contained a note about the presence of a murmur recorded by the breeder’s veterinarian. Possible reasons for this finding remain speculative and include the following options: (1) the breeder’s veterinarian did not notice the murmur, (2) the health certificate sections of the pet passports were filled in without having examined the puppy, (3) the breeder’s veterinarian did hear the murmur, but  failed to record it in the pet passports.Though the presence of a murmur was recorded in the medical records of the referring veterinarian in 94% of the cases, the pet passports contained this information in only 63% of the cases. This finding suggests that the medical records seem to be a more reliable source of information than the pet passports. However, medical records are not accessible to the pet owners who are about to buy a puppy from a breeder. The reason for the inconsistent documentation of murmurs by first opinion practicing veterinarians remains unclear.Because louder murmurs are more likely to be pathologic, a younger age at referral would be expected in dogs with a loud murmur. However, the intensity of the murmur as judged by the referring veterinarian did not show a correlation with the age at referral. The two most common anomalies for which effective surgical correction is also available, severe pulmonic stenosis and hemodynamically relevant left-to-right shunting patent ductus arteriosus, are typically associated with a loud murmur. Even in this subgroup of dogs no correlation was found between the age at referral and the murmur intensity. Whether an owner eventually makes an appointment with a veterinary cardiology specialist or not, and if so when, depends not only on the referring veterinarian’s advice, but also the owner’s perceptions, motivation and financial background. This aspect was not investigated in the present study. However, the authors believe that it is important that a first opinion veterinary practitioner carefully performs cardiac auscultation and in case of a murmur recommends immediate referral to a veterinary cardiology specialist. This is the only way to prevent legal issues for the breeder and make sure that a reliable diagnosis is reached together with a prognosis and a sound therapy advice.A non-pathologic murmur was found in only 6% of the referred dogs. The reason for this low number could be that the median age of the population at referral was higher (6.3 months) than the age when most innocent murmurs spontaneously resolve in puppies (median age of 3 months) . In addiIn the 5-year period of the present study, only three dogs were identified whose murmur was caused by a congenital heart defect and not recognized before the referral. This finding suggests that the first opinion veterinary practitioners in the Netherlands are good at recognizing cardiac murmurs, at least in cases when they examined individual animals. However, when health checks of litters were performed by the breeders’ veterinarians at the first health screening, the number of documented cardiac murmurs was low. This can be explained by the fact that screening an individual puppy is easier than a whole litter, especially if the litter screening takes place at the breeder’s home, under suboptimal circumstances instead in a quiet consultation room.Congenital cardiac anomalies can lead to morbidity and mortality –9, 14–19Aortic stenosis, pulmonic stenosis and left-to-right shunting patent ductus arteriosus were found to be the most common causes of a pathologic murmur in the present study, similarly to other reports on congenital cardiac anomalies . In variIn the present study, the median age of a dog with a suspected congenital cardiac anomaly was 6.3 months old when it was examined by a veterinary cardiology specialist. The age when dogs with left-to-right shunting patent ductus arteriosus and severe pulmonic stenosis underwent a cardiac intervention in our study was among the lowest compared to published reports. However, if we take into consideration that based on our findings, puppies received their first vaccination and health check at a median age of 6.4 weeks, the delay in referral of more than three months to a veterinary cardiology specialist seems unnecessarily long. Because the second and third vaccinations routinely take place at 9 and 12 weeks of age together with repeated health examinations, the median age of 3.3 months seems still late for the first documentation of a murmur. This finding is especially interesting because the health examination at 9 and 12 weeks of age takes place by the new owner’s veterinarian, on an individual basis. The reason for the delay between the murmur documentation and the visit to the cardiology specialist remains unknown. Delay in referral can be caused by three parties: (1) by the referring veterinarian, who might not recommend immediate referral, (2) by the owner, who does not see the urgency of revealing the cause of a murmur, or (3) by the referring hospital. In one third of the referred dogs in the present study, the veterinary cardiology specialist recommended an interventional therapy for the congenital anomaly, which represents a relative high prevalence of severe and correctable anomalies. This finding emphasizes the importance of recommending referral to all owners of puppies with a murmur to a veterinary cardiology specialist, and preferably as soon as possible and ideally before the puppy is sold to the new owner.How the echocardiographic findings of the non-cardiologist affected the decision about referral to a veterinary cardiology specialist remains speculative. Also, the number of dogs that after such an echocardiogram were not referred to a veterinary cardiology specialist remains unknown. Possible reasons why dogs with a suspected congenital cardiac anomaly were first referred to a non-cardiologist for echocardiography can have several reasons, such as lower examinations costs, shorter travel distance, and a possibly quicker and more flexible appointments. However, throughout the study period the cardiology service offered appointments with a veterinary cardiology specialist within a week of receiving the referrals.The present study has several limitations. The first limitation is that the date when the murmur was documented for the first time was unknown for many dogs because of unavailable pet passports or medical records. This shortcoming results from the retrospective nature of the study. Another limitation is that in the study period three cardiologists performed the examinations, which might have affected the assessment of murmur intensity due to the subjective nature of this test. In addition, comparing murmur intensity of two veterinarians based on retrospectively gained recorded findings is less reliable because the auscultations took place on different days  and under different circumstances, moreover it can be effected by the natural history of the disease. Finally, the major question why puppies with a cardiac murmur are not immediately referred to a veterinary cardiology specialist remained unanswered.Only 10% of the puppies in the study were referred to a veterinary cardiology specialist for murmur investigation before they were sold to a new owner. Referral prior to re-homing would have been feasible if the murmur had been detected and documented by the breeder’s veterinarian, if referral was offered by the breeder’s veterinarian and the referral accepted by the breeder. This study emphasizes the importance of early referral, to reduce the medical, financial and emotional consequences of delayed murmur investigation for all parties involved. The reasons for delayed referral to veterinary cardiology specialists remain undetermined. However, the importance of early referral is clear, as the vast majority of the population had congenital defects, and as interventional procedures to correct severe defects were recommended for about a third of the dogs in this study. When murmur investigation is carried out prior to re-homing, new owners can make an informed decision when taking on a puppy with congenital heart disease.


This study aims to compare the perceptions of nurses and families on the needs of the relatives of the patients in Intensive Care Unit (ICU).patients and nurses. The item “To be assured the best care possible is being given to the patient” was the top priority for both groups. Mean assurance/proximity and information dimensions of relatives were significantly higher compared to nurses (p < 0.001). No significant difference was found between the perception of patient relatives and nurses related to support and comfort dimensions (p < 0.05).This cross-sectional study was conducted in the ICU of a university hospital. The study comprised 213 critical care patients’ relatives and 54 nurses working in the same ICU. Data were collected using the Turkish version of Critical Care Family Needs Inventory (CCFNI) and a questionnaire on the characteristics of the participants. The difference between the perceptions of families and nurses was analyzed using Student t-test. Results: CCFNI’s assurance/proximity subscale mean scores ranked first among bothThe needs of the relatives of patients are underestimated by nurses. This inhibited the performance of ICU nurses in line with the holistic care approach. Educational objectives that include the needs of ICU patients’ relatives should be incorporated into the undergraduate and in-service training of nurses. Policies should be established to create space and time for effective relative-nurse communication. The stress level of the relatives of the patients who are admitted to Intensive Care Unit (ICU) is quite high due to serious and unstable conditions of their patients . MoreoveFamily members may experience extreme stress and anxiety, feel helpless and unable to cope with this situation . Fear ofCorrect assessment of their needs is one of the first steps in providing appropriate health care to ICU patients and their families. Examining family members ’and nurses’ perceptions of the needs of inpatient families in the ICU can provide an overview of the improvement of practices in this unit. Despite increasing evidence obtained from studies conducted in this area, the number of studies conducted in the Turkish society in the literature is very low .The socio-cultural and geographic contexts responsible for the diversity of family needs of ICU patients can be very important factors, so evidence from different cultures of the world is important . The objThe present cross-sectional study was carried out at the Anesthesia Intensive Care Unit of Dokuz Eylül University Medical Faculty Hospital, one of the two major university hospitals in Izmir. The unit has a capacity of 13 beds, average staffing is two patients per nurse and annual patient capacity ranges between 450 and 500. The ICU, which provides tertiary-level intensive care, offers services to postoperative cases as well as patients who require mechanical ventilation for reasons such as polytrauma, chronic obstructive pulmonary disease, sepsis, and head trauma. Three days a week, medical information is given to the patient’s relatives by a critical care physician. Afterwards, the attending nurse gives a bedside briefing on the day of the visit about the necessary materials and nursing care, and the questions of the patient’s relatives are answered.In this study, the average number of patients per year was accepted as a population size of 500, as only one family member was interviewed for each patient. The sample size representing the population was calculated as 278 using a 95% confidence interval, a 5% margin of error and unknown prevalence. A total of 213 family members of patients enrolled in the study, coverage rate was 76.6%. The study targeted all 57 nurses working in the same critical care unit, and 94.7% (n:54) coverage was achieved.Inclusion criteria for patient families included.(1) Age of 18 years or older(2) Being a relative of the patient who signs informed consent form at hospital admission and related by kinship or marital relationship with the patient.(3) visited the critically ill patient within 24 to 72 h after admission of the patient over 18 years of age in the ICU. Although the indications for hospitalization are very diverse, all of them are patients who are connected to a mechanical ventilator and whose relatives have been informed that they are in high danger of life.(4) willing to participate in the study(5) being able to read and write.The inclusion criterion for nurses, on the other hand, was to be working in the Department of Anesthesiology and Reanimation Intensive Care Unit for at least six months. All nurses serve in the same working order alternately in 8-and 16-hour shifts.The research data were collected using a questionnaire form, where the characteristics nurses and patients were questioned separately, and the Turkish version of Critical Care Family Need Inventory (CCFNI) . The queIn this study, Cronbach Alpha value of the scale was calculated as 0.89 for patient relatives and 0.95 for nurses.The process of adapting the scale to Turkish was mainly carried out through relatives of patients, however, expert opinion from six intensive care nurses was received in assessment of the validity of the scope and then the expert panel included two intensive care nurses in addition to relatives of patients . In a stEthical approval was granted by the Dokuz Eylül University Non-Clinical Studies Ethics Committee, and a research permit was obtained from the Head of the Intensive Care Unit of the Dokuz Eylül University Faculty of Medicine Department of Anesthesiology and Reanimation . Data were collected between July 2018 and January 2019. Participants were verbally informed by an ICU physician about the objectives of the study and their written consent was obtained making clear that their participation would be on a voluntary basis. Confidentiality was preserved though anonymity of participants by refraining from questioning their names. Questionnaires were distributed to the participants by the same researcher, and they were asked to leave the completed questionnaires in the drop-off boxes placed in the waiting room. The research team explained the objectives of the study to the nurses, who were then given 30–35 min to fill in the questionnaires in-hospital during their break time. Eight patient relatives who failed to complete the questionnaires were excluded from the study.t-test was used to evaluate the difference between perceptions of families and nurses. Whether the data indicated a homogeneous distribution checked using the Levene test, and in cases where it was not distributed homogeneously, the equal variations not assumed p value was used. A p-value of <0.05 was regarded as statistically significant.Data analysis was performed using SPSS 15.0 statistics package program. Independent The sociodemographic characteristics of the relatives and nurses are given in n = 4) of the nurses reported that they were previously admitted to intensive care, 68.5% (n = 37) stated that at least one of their relatives was in an ICU.The mean age of the nurses was 31,9 ± 6,1 and %81,5 was female. Nurses with critical care experience of five years or more accounted for 35.2%. While 7.4% .The experience of nurses when their own relatives have been in ICUs has been evaluated. A statistically significant difference in scale between nurses who had and had no experience of having a relative staying in intensive care was found for only one article. While nurses  who had experience of having a relative staying in intensive care unit gave higher score for “To talk to the same nurse every day” article nurses  having no such experience gave lower score (This study evaluates the degree of coherence between the perceptions of the ICU nurses who assume the most important responsibility for fulfilling the needs of the patients as well as their families in ICU and the needs of patient relatives. It is very important to identify the difference between the perceptions of nurses and the needs of patients’ relatives in the provision of family-centered nursing services in intensive care units.Coherent with the literature, the results of this study showed that there are similarities and differences in terms of family members and nurses’ perceived need for patient relatives . Family Assurance and proximity subscales in the CCFNI developed by In many studies, assurance dimension was perceived as the highest priority need for both groups . In a liAlthough the mean score of family members was higher, the second most important need dimension reported by both groups was ‘information’. In addition, the most basic needs of patient’s relatives, such as knowing what was done to the patient, what kind of treatment was applied and why these treatments were performed and obtaining information about the changes in the patient’s condition were not considered as priority by nurses. Moreover, the article titled “To be called at home about changes in the patient’s condition” regarding information dimension was in the second and 12th rank for families and nurses, respectively. This finding showed that patients’ need for information was not adequately perceived by nurses as described in the literature . In TurkProviding adequate information about the patient’s condition, treatment and prognosis also fulfills the needs of families to trust the health system as well as healthcare employees . To fulfThe “support and comfort” dimension of patient relatives’ needs was perceived as the least important factor by both nurses and patients as described in the literature . In the Considering the fact that the study was performed in single center where the level of education of patient relatives is relatively high, it should be noted that the generalizability of our results to the population in Turkey is limited. However, the present study similar to other studies in different ICUs in Turkey  in termsThis study revealed that the most fundamental requirement for both patients and families was assurance and proximity in hospital staff. The second most important factor was the need for information that requires personal communication. However, in both dimensions, the fact that nurses’ scores were lower than those of patient relatives indicates that nurses perceive the needs of patient relatives less than their actual needs.Our study results support the evidence that Turkish version of CCFNI is a valid tool that allows evaluation of the family’s needs and nurses’ perception on these needs . HoweverIn this framework, new strategies such as, flexible visiting hours, improved participation of nurses in ’visiting and “informing” hours and enhancing the quality of information / counseling processes for patient relatives should be addressed . However10.7717/peerj.11125/supp-1Supplemental Information 1Click here for additional data file.10.7717/peerj.11125/supp-2Supplemental Information 2Click here for additional data file.


This paper studies the position and stability of equilibrium points in the circular restricted three-body problem under the influence of small perturbations in the Coriolis and centrifugal forces when the primaries are radiating and heterogeneous oblate spheroids. It is seen that there exist five libration points as in the classical restricted three-body problem, three collinear  He considered the effect of a small perturbation in the Coriolis force on the stability of the equilibrium points keeping the centrifugal force constant, He found that the collinear points are still unstable but the triangular points bear a relation between the critical value of the mass parameter µc and the change 2. Studied the effect of small perturbations in the Coriolis and centrifugal forces on the stability of equilibrium points in the restricted problem. They observed that the collinear points remain collinear, but the triangular libration points nearly form equilateral triangles with the primaries, they also revealed that these perturbations have null effects on the stability of collinear points, but have considerate effects on the stability of triangular points. The R3BP with disturbing agents  was investigated by several scientists. Various researchers5 considered small perturbations in the Coriolis and centrifugal forces and described their effects on the motion of the third body6. Examined the equilibrium points in the perturbed restricted three body problem with triaxial and luminous primaries. He observed that the position of the five libration points are affected by the radiation, triaxiality and a small perturbation in the centrifugal force, but not affected by that of Coriolis force. He also found that the Coriolis force has a stabilizing tendency, while the centrifugal force, radiation and oblateness of the primary body have destabilizing effects7. Deals with the stationary solution of the planar restricted three body problem when the primaries are heterogeneous oblate spheroid with three layers of different density and source of radiation. They showed that the triangular equilibrium points 8. Studied the circular restricted three body problem when the both primaries are heterogeneous spheroid of three layers of different densities and the infinitesimal body varies its mass. They locate all the equilibrium points of both the in-plane and out-of-plane and proved that they are unstable9. Investigated the non linear stability of the triangular libration point L4 in the restricted three body problem when the smaller primary is a heterogeneous spheroid. They observed that the positions of the non collinear equilibrium point L4 is significantly affected by the heterogeneous oblate spheroid with three layers having different densities and this point is stable in the nonlinear hence in the range of linear stability except at three points at which KAM Theorem fails.The restricted three-body problem (R3BP) deals with the motion of an infinitesimal particle under the Newtonian gravitational attraction of two bodies, called primaries. It is known that in the planar general three bodies attracting each other according to Newtonian gravitational law, there exist only two permanent central configurations, namely the collinear (Eulerian) and the equilateral (Lagrangian). In the first case, the primary bodies of the problem lie on a single straight line while in the second one, the primary bodies lie at the vertices of an equilateral triangle. The restricted three- body problem possesses five equilibrium points In this paper, our aim is to study the effects of small perturbations in the Coriolis and centrifugal forces when the both primaries are heterogeneous oblate spheroids and source of radiation pressure. This research paper is organized as follows: in “m27:We consider the primaries of masses and M = m1 + m2R = dimensional distance between the primaries.q1 and q2 are the radiation factors of the primaries. The resultant force acting on the infinitesimal body is 6, The mean motion n of the primaries isFrom Eq.  we obtaiThe position of equilibrium points can be found by setting The triangular points are the solutions of equations entclass1pt{minimarom Eqs.  we have5When the primaries are neither radiating nor heterogeneous spheroids  an an12) anii = 1,2,$$\end{doii = 1,2,$$\end{do11, we compute the roots of the algebraic polynomial equations corresponding to the collinear points Li  numerically, with the help of Mathematica (wolfram2010) and Matlap (R2007b) software packages. The binary system Upsilon4Eridani portrayed µ = 0.4918, q1 = 0.9339, q2 = 0.9411,,, k1 = 1.58302 × 10–7, k2 = 9.83933 × 10–18, k3 = 3.13153 × 10–8. We obtain the coordinate of the collinear equilibrium points for different cases as classified in the following order while the effect of distances from primaries and the positions of the collinear points for different cases shown in Table (i)Absence of radiation pressure of the both primaries, small perturbations in the Coriolis and centrifugal forces and heterogeneous oblate spheroid (ii)A small perturbation in the centrifugal force with heterogeneous oblate spheroid only(iii)Heterogeneous oblate spheroid only(iv)Radiation pressure of the bigger primary with heterogeneous oblate spheroid only(v)The radiation pressure of the both primaries only(vi)Radiation pressure of the smaller primary with heterogeneous oblate spheroid only(vii)Presence of radiation pressure of the both primaries, small perturbations in the Coriolis and centrifugal forces and heterogeneous oblate spheroidsFollowingWe substitute The corresponding characteristic equation of the variational Eqs.  can be wFor the triangular points, we have computed the second partial derivative of  the Eq. , and theSubstituting these values into Eq.  and replIts rootswithNow,And(i)When n by Eq.  are nega(ii)When n by Eq.  are same(iii)When Since 7 when both primaries are radiating and heterogeneous spheroids with three layers of different densities. In this case 2. Also in the absence of the heterogeneous spheroids 6 when neglecting the triaxiality of the primaries 1. It is obvious that all perturbing parameters except The solution of the equation L1.Now we consider the stability of the collinear points. At first we consider the point corresponding to For this point, L2 and L3,Similarly for points corresponding to s and t are real. Thus the motion around the collinear points is unbounded therefore the collinear points are unstable. It shows that the nature of the stability of collinear points is not affected by the changes in the Coriolis and centrifugal forces, heterogeneous oblateness, or radiation pressure forces of the both primaries and they remain unstable. The Tables Now the characteristics Eq.  becomes27 due to presence of small perturbations in the Coriolis and centrifugal forces. If the primaries are neither heterogeneous spheroid nor radiating and there are no perturbations in the Coriolis and centrifugal forces, the Eq. .The Eqs. (–3.The Eq The Eq.  differs  the Eq.  represenn by Eq.  shows thWe have investigated the location and stability of equilibrium points under the influence of small perturbations in the Coriolis and centrifugal forces when both the primaries are heterogeneous spheroids with three layers and radiating. It is found that the stability behavior of the collinear points remains unchanged despite all the perturbations involved and they are unstable. The triangular points are stable for