Aya Houssein
email: .jpegaya.houssein@hotmail.com

Di Ge

Steven Gastinger

Remy Dumond

Jacques Prioux

A novel algorithm for minute ventilation estimation in remote health monitoring with magnetometer plethysmography

Keywords:

Purpose The purpose of this study was to evaluate the accuracy of minute ventilation ( ̇ ) estimation using a novel method based on a non-linear algorithm coupled with cycle-based features. The experiment protocol was well adapted for remote health monitoring applications by exploiting data streams from respiratory magnetometer plethysmography (RMP) during different physical activity (PA) types. Methods Thirteen subjects with an age distribution of 24.1 ± 3.4 years performed thirteen PA ranging from sedentary to moderate intensity (walking at 4 and 6 km/h, running at 9 and 12 km/h, biking at 90 W and 110 W). In total, 3359 temporal segments of 10s were acquired using the Nomics RMP device while the iWorx spirometer was used for reference ̇ measurements. An artificial neural network (ANN) model based on respiration features was used to estimate ̇ and compared to the multiple linear regression (MLR) model. We also compared the subject-specific approach with the subject-independent approach. Results The ANN model using subject-specific approach achieved better accuracy for the ̇ estimation. The bias was between 0.20 ± 0.87 and 0.78 ± 3 l/min with the ANN model as compared to 0.73 ± 3.19 and 4.17 ± 2.61 l/min with the MLR model. Conclusion Our results demonstrated the pertinence of processing data streams from wearable RMP device to estimate the ̇ with sufficient accuracy for various PA types. Due to its low-complexity and real-time algorithm design, the current approach can be easily integrated into most remote health monitoring applications coupled with wearable sensors.

Introduction

Respiratory failure affects millions of people [START_REF] Schindhelm | Methods and apparatus for monitoring and treating respiratory insufficiency[END_REF] whose lungs are unable to inspire sufficient oxygen or expire sufficient carbon dioxide to ensure the homeostasis of the body. Continuous monitoring of respiratory functions is essential to detect respiratory pathologies such as asthma, obstructive sleep apnea, and chronic obstructive pulmonary disease. It also allows the monitoring of both hospitalized and home care patients to predict high-risk situations, and it is thus considered a vital tool for health care providers [START_REF] Folke | Critical review of non-invasive respiratory monitoring in medical care[END_REF][START_REF] Sierra | Non-invasive monitoring of respiratory rate, heart rate and apnea[END_REF]. Numerous studies have shown that minute ventilation ( ̇ ) provides accurate markers for acute respiratory dysfunctions [START_REF] Schlesinger | Applications of a noninvasive respiratory volume monitor for critical care medicine[END_REF][START_REF] Voscopoulos | Evaluation of a novel noninvasive respiration monitor providing continous measurement of minute ventilation in ambulatory subjects in a variety of cinical sceniaros[END_REF][START_REF] Voscopoulos | Continous noninvasive respiratory volume monitoring for the identification of patients at risk for opioid-induced respiratory depression and obstructive breathing patterns[END_REF]. It is defined as the volume of air inhaled or exhaled per minute, or equivalently as the product of the tidal volume ( ) and the breathing frequency (Fr), ̇ = * . Due to its importance in respiratory medicine, the precise measurement of ̇ over time remains a subject of research interest [START_REF] Chhabra | Interpretation of spirometry: Selection of predicted values and defining abnormality[END_REF].

In practice, conventional spirometric techniques have frequently been used to accurately measure the ̇ [START_REF] Miller | Standardisation of spirometry[END_REF]. However, these techniques require the use of a mouthpiece or a mask inconvenient to wear during various physical activities (PA) and thus unfitted for long-term monitoring, particularly with ambulatory settings. Furthermore, these devices add dead space and resistance to normal breathing [START_REF] Askanazi | Effects of respiratory apparatus on breathing pattern[END_REF][START_REF] Perez | Separation of factors responsible for change in breathing pattern induced by instrumentation[END_REF][START_REF] Rameckers | The influence of a mouthpiece and noseclip on breathing pattern at rest is reduced at high altitude[END_REF]). Additionally, the measurements are usually performed in laboratories, and do not necessarily reflect ̇ during daily life PA of patients at their home or workplace. To overcome these difficulties, indirect ̇ measurements have been developed by inferring from the rib cage and abdomen movements since the lung volume is a function of these two variables [START_REF] Konno | Measurement of the separate volume changes of rib cage and abdomen during breathing[END_REF]. A number of systems and devices have been investigated, including the magnetometers [START_REF] Mccool | Tidal volume and respiratory timing derived from a portable ventilation monitor[END_REF] and the respiratory inductive plethysmography (RIP) belts [START_REF] Leino | Validation of a new respiratory inductive plethysmograph[END_REF][START_REF] Hollier | Validation of respiratory inductive plethysmography (lifeshirt) in obesity hypoventilation syndrome[END_REF]. [START_REF] Gastinger | Estimates of ventilation from measurements of rib cage and abdominal distances: a portable device[END_REF] have developed a portable respiratory magnetometer plethysmography (RMP) system, based on the studies of [START_REF] Mccool | Estimates of ventilation from body surface measurements in unrestrained subjects[END_REF] and [START_REF] Paek | Breathing patterns during varied activities[END_REF]. It is composed of two pairs of electromagnetic coils, each composed of a transmitter and a receiver attached to the rib cage and abdomen to measure the anterior and posterior distances of the rib cage and abdomen. [START_REF] Gastinger | Estimates of ventilation from measurements of rib cage and abdominal distances: a portable device[END_REF] have proposed an accurate method to estimate the ̇ using RMP during resting and walking activities.

The calibration procedure is key to the estimation accuracy of ̇ . Multiple linear regression (MLR) model is the most commonly used calibration technique based on statistical linear regression. It was adopted by [START_REF] Mccool | Tidal volume and respiratory timing derived from a portable ventilation monitor[END_REF] and [START_REF] Gastinger | Estimates of ventilation from measurements of rib cage and abdominal distances: a portable device[END_REF]. Other authors have demonstrated that non-linear machine learning models and especially the artificial neural network (ANN) are more suited to the variability of breathing, as movements of the respiratory system are often associated with non-linear and compound thoracoabdominal interactions during variable breathing [START_REF] Raoufy | Nonlinear model for estimating respiratory volume bases on thoracoabdominal breathing movements[END_REF][START_REF] Lin | Comparison of artificial neural network (ann) and partial least squares (pls) regression models for predicting respiratory ventilation: an exploratory study[END_REF]. [START_REF] Dumond | Estimation of respiratory volume from thoracoabdominal breathing distances: comparison of two models of machine learning[END_REF] also demonstrated that the ANN is better than the MLR model for predicting other respiratory variables from RMP, such as .

To investigate the potential of non-linear models on the accuracy of ̇ estimation using RMP, we compared the ANN model with the MLR model in [START_REF] Gastinger | Estimates of ventilation from measurements of rib cage and abdominal distances: a portable device[END_REF]. To our knowledge, only [START_REF] Gastinger | Estimates of ventilation from measurements of rib cage and abdominal distances: a portable device[END_REF] and [START_REF] Dumond | Estimation of respiratory volume from thoracoabdominal breathing distances: comparison of two models of machine learning[END_REF] evaluated RMP to estimate respiratory variables. While [START_REF] Dumond | Estimation of respiratory volume from thoracoabdominal breathing distances: comparison of two models of machine learning[END_REF] demonstrated the feasibility of the ANN model, ̇ estimation was not included. [START_REF] Gastinger | Estimates of ventilation from measurements of rib cage and abdominal distances: a portable device[END_REF], on the other hand, evaluated the ̇ estimation accuracy with resting and walking activities only. Another major contribution of our study is the use of cycle-based respiration features to take into account the phase differences from the raw distance signals instead of the sample-wise regression methods proposed by [START_REF] Dumond | Estimation of respiratory volume from thoracoabdominal breathing distances: comparison of two models of machine learning[END_REF] and [START_REF] Gastinger | Estimates of ventilation from measurements of rib cage and abdominal distances: a portable device[END_REF]. We hypothesized that measurements of distance changes from the rib cage and abdomen during light to moderate PA contain information about and , and that a non-linear ANN model would improve the estimation results with respect to the reference spirometer measurements of ̇ .

Materials and Methods

This study is part of the Sherpam (Sensors for Health Recording and Physical Activity Monitoring) project (https: //project.inria.fr/sherpam/) that aims to develop a new generation monitoring system to allow health monitoring at home, during indoor and outdoor activities (at work, shopping, sports practicing, etc). Concretely, the project has the ambition to improve the recognition of PA [START_REF] Rahman | Advanced classification of ambulatory activities using spectral density distances and heart rate[END_REF]) and the estimation of associated energy expenditure in healthy subjects [START_REF] Khreis | Breathing rate estimation using kalman smoother with electrocardiogram and photoplethysmogram[END_REF][START_REF] Houssein | Estimation of respiratory variables from thoracoabdominal breathing distance: a review of different techniques and calibration methods[END_REF]. A modular Android application aggregates data from various types of sensors and transmits these data to a remote aggregation server for storage and analysis. A web application provides access to the data maintained on the aggregation server, and it can also send alerts to the user's smartphone (see Figure 1). Details on data collection, experimental protocol, instrumentation, and pre-processing data are presented in this section.

Subjects

Thirteen subjects, nine men and four women, aged 24.1 ± 3.4 years voluntarily took part in this study (height 174.5 ± 9.4 cm, weight 67.5 ± 9.2 kg, body mass index 22.21 ± 2.32 kg. -2 ). All procedures involving human subjects were approved by the University of Rennes 2 Research Ethics Committee. A written assent has been signed by each subject who had been informed about the development of the study. The subjects were healthy and did not present any pathological disorder.

Experimental protocol

The experiment protocol was composed of a variety of activities of various intensities. During data acquisition, each subject performed three successive postures activities with intervals of 3 minutes of rest: sitting, standing, and lying laterally, for a duration of 3 minutes. These postures were performed in two modes of breathing, natural and paced breathing. In paced breathing mode, subjects control their breathing by following a metronome, with the rhythm fixed at 50 breaths per minute (bpm). After a period of rest, each subject performed a set of PA in a random order: working on a computer, walking at 4 km/h (slope 2%) and 6 km/h, running at 9 km/h (slope 2%) and 12 km/h, cycling at 90 and 110 W. Walking and running activities were performed on a treadmill, and cycling on a cycle ergometer. Each activity was performed for 6 min, separated by a 5-minutes rest. In total, 54 min of data were recorded and analyzed for each subject. The tests were conducted under controlled laboratory conditions.

Measurement systems

During all activities, subjects are equipped with a Nomics RMP device (Nomics s.a, Liège Science Park, Belgium), and an iWorx spirometer (BIO-SP304). RMP includes two pairs of electromagnetic coils connected to a device, and each pair is composed of a transmitter and a receiver to measure the temporal variations of the four distances, namely the anteroposterior displacement of the rib cage and abdomen, and the axial displacement of the chest wall and spine (Figure 2). These data are recorded at a frequency of 15 Hz. The spirometer is used as a reference with a sampling frequency of 100 Hz. All data from the electromagnetic coils and the spirometer were exported under Matlab for processing.

Data processing 2.4.1. Preprocessing data

Data collected from spirometer and RMP contains noise and artefacts, especially for those collected during PA (cf upper panel of Figure 3). To reduce noise and artefacts, a low-pass filter was applied with a cut-off frequency of 1.5 Hz, retaining only breathing-related frequency components for human activities between 0.1 and 0.5 Hz. Note that the filtered results in the lower panel of Figure 3 have variable phase delays: peaks and troughs are not synchronized and temporal delays are unfixed among the four channels. Thus, any sample-by-sample regression method would be biased due to the desynchronization effects between channels, and that is why we propose here a cycle-wise estimation method by applying regression on features of each cycle instead of each sample.

Segmentation

Cycle-by-cycle breathing pattern parameters ( , , ̇ ) were calculated from the spirometer data. Then, all respiratory signals measured by RMP and spirometer were divided into non-overlapping segments of 10 seconds. A total of 3359 temporal segments was obtained for all subjects. [START_REF] Gastinger | Estimates of ventilation from measurements of rib cage and abdominal distances: a portable device[END_REF] and [START_REF] Dumond | Estimation of respiratory volume from thoracoabdominal breathing distances: comparison of two models of machine learning[END_REF], have assumed that the respiratory volume can be estimated as a weighted sum of the anteroposterior displacement of the rib cage and abdomen, and the axial displacement of the chest wall and spine on a sample-wise basis:

Features extraction

= . 1 + . 2 + . 3 + . 4 + (1)
where , , and are the regression coefficients to be identified, and is the error of the model. We, however, argue that the sample-wise regression method proposed in [START_REF] Gastinger | Estimates of ventilation from measurements of rib cage and abdominal distances: a portable device[END_REF] and [START_REF] Dumond | Estimation of respiratory volume from thoracoabdominal breathing distances: comparison of two models of machine learning[END_REF] does not take into account the phase differences from RMP sensors (cf Figure .3b) whereas features extracted from a segment are indifferent to these phase shifts. [START_REF] Liu | Improved regression models for ventilation estimation based on chest and abdomen movements[END_REF], on the other hand, have shown that by including features such as the 10th and 90th percentiles of the abdominal and rib cage signal, the dominant frequency of the rib cage and abdominal variations, the estimation accuracy of ̇ can be further improved. In the current study, we propose to include two features closely related to ̇ . One is the interdecile range of the RMP signals to reflect the volume changes in the thoracoabdominal distances in each segment. It is defined by the difference between the 90th and 10th percentiles of the signal in each temporal segment, typically containing several breathing cycles. Another one is the dominant frequency of the respiratory signals, calculated from its periodogram. The product of the volume change and is indeed ̇ as discussed in the introduction. In the following, regression models are calculated using these two features per channel to estimate ̇ for each temporal segment.

Regression and statistical methods

An ANN model was designed and implemented to introduce the non-linear relationships 1) between the variations of thoracoabdominal distances represented by features and the volume change per segment, 2) the measured ̇ as the product of volume change and . An ANN consists of neurons organized into a series of layers of nodes interconnected by weighted arcs. The ANN model learning procedure is based on a feedforward/backward approach. In our study, we used a three-layer architecture as shown in Figure 4 containing an 8-node input layer, each corresponding to a feature, followed by a hidden layer, and then a single-node output layer to output the target value ̇ . The hyperbolic tangent sigmoid transfer function transig was used for the hidden layers, and the linear transfer function purelin for the output layer.

The ANN model was trained using two approaches: a subject-specific approach (ANNsp) in which ANN model was trained for each subject separately. The estimation performance was assessed using 5 fold cross-validation. The second ANN approach was a subject-independent approach (ANNid) in which ANN model was trained using all but one subject's data. The performance was calculated for the left-out subject, each subject was left out in turn. We compared also ANNsp to a linear model (MLR) trained using a subject-specific approach as used by [START_REF] Gastinger | Estimates of ventilation from measurements of rib cage and abdominal distances: a portable device[END_REF]. The performance of models was evaluated by their root mean square error (RMSE):

= √ ∑ =1 ( ̇ -̇ ) 2 (2)
where ̇ and ̇ represent ̇ from estimation and the spirometer measurement respectively. is the total number of temporal segments.

We have also evaluated the agreement between ̇ and ̇ by plotting the values of ̇ against the values of ̇ , and by calculating the coefficient of determination. The mean differences (bias) were also reported.

Results

Comparison between ANNsp and ANNid

RMSE of the two training approaches (ANNsp and ANNid) of the ANN model is reported in the Figure 5. Our results show that ANNid yielded significantly larger errors than ANNsp. The RMSE range is 1.60-7.85 l/min for the ANNid while that of the ANNsp is 0.85-2.85 l/min. In addition, in both ANN models the error increases with the PA intensity. Specifically, the RMSE of postures activities in the ANNsp approach is between 0.85 l/min and 1.05 l/min (for naturally sitting and metronome lying respectively). These RMSE values were much lower than those of walking (4 km/h) and running (12 km/h), between 1.52 l/min and 2.85 l/min respectively.

The mean values of ̇ measured by the spirometer ( ̇ ), and estimated by the magnetometers ( ̇ ) are illustrated in Figure 6. Our results show that there are no significant differences between ̇ and ̇ for all activities in the ANNsp (p>0.05). Likewise, for ANNid, there are no significant differences between mean ̇ and ̇ for natural postures activities (standing, lying, sitting and computer work) and walking at 4 km/h (p>0.05), while a highly significant difference (p<0.01) between ̇ and ̇ appears for PA (walking at 6 km/h, running and biking).

The mean differences between ̇ and ̇ (bias) were also calculated from all activities for the two ANN approaches (ANNsp and ANNid) (Table 1). Our results show that the bias is low for all activities in the ANNsp. In addition, the bias for the ANNid (bias range 0.36-4.78 l/min) is significantly greater (p< 0.01) than the bias for the ANNsp (bias range 0.02-0.78 l/min) except for postures activities and biking at 90 W. Indeed, the bias reaches its maximum in higher intensity exercises such as running at 12 km/h for both ANN approaches: reaching 0.78 ± 3.00 and 4.78 ± 7.23 l/min for ANNsp and ANNid respectively. The pooled data of ̇ for all postures and PA are shown in Figure 7. We note that ̇ was highly correlated with ̇ ( 2 =0.98) in ANNsp (Figure 7a) compared with that of the ANNid ( 2 =0.84) (Figure 7b) .

Comparison between ANNsp and MLR

The RMSE was also used to compare the ANNsp and MLR model (Figure 8). The RMSE range of the ANN model (0.84 -2.84 l/min) is significantly lower (p<0.05) than that of the MLR model ( 2.73 -5.19 l/min). Moreover, for the MLR model in all activities, there is a highly significant difference (p< 0.01) between mean values measured by spirometer ( ̇ ), and those estimated by magnetometers ( ̇), as shown in Figure 6. In addition, the bias range of the ANNsp (0.03 -0.78 l/min) is significantly lower (p<0.01) than that of the MLR model (1.15 -4.17 l/min) for all the activities (Table 1).

Figure 7 (a andc) shows that the ANNsp model is better correlated with the reference ( 2 = 0.98) than MLR model ( 2 = 0.91) for the estimation of ̇ . In addition, the disparity from the line of identity and thus the errors are more important when the intensity of PA is higher.

ANNsp optimization

Results presented in Figure 9 show that the optimal number of nodes in the hidden layer of the ANN structure was 10 and the optimal number of layers was 1, for all categories of activities. Further, increasing the number of nodes in the hidden layer and the number of layers no longer contributes to lower RMSE. On the contrary, even worse results are observed when more nodes and layers are added resulting in an overfitting configuration.

Discussion

The purpose of this study was to evaluate the accuracy of RMP for ̇ estimation using a novel method based on cycle-based features during different types of PA based on the studies of [START_REF] Liu | Improved regression models for ventilation estimation based on chest and abdomen movements[END_REF] and [START_REF] Dumond | Estimation of respiratory volume from thoracoabdominal breathing distances: comparison of two models of machine learning[END_REF]. [START_REF] Gastinger | Estimates of ventilation from measurements of rib cage and abdominal distances: a portable device[END_REF] have previously validated RMP for resting and walking activities using a sample-wise linear regression method. In our study, RMP was also validated for ̇ estimation during different postures and PA of daily life: sitting, standing, lying, running, walking, biking, working on PC. Its small size and light-weight are the key advantages as an alternative to spirometers that limit the free movement of the subject during ambulatory conditions.

Our ANNsp method showed no significant difference compared with the reference measurements from spirometer ( ̇ ), in terms of both RMSE and bias. This result is found for all activities: sitting, standing, lying, walking, running, and biking. We have thus proven the validity of RMP during light to moderate PA. On the other hand, significant differences exist between ̇ and ̇ using either the ANNid or the MLR model. The ANNsp method achieved better results ( 2 = 0.98) compared to those using the MLR model ( 2 = 0.91) and ANNid ( 2 = 0.84). These results validate our hypothesis and the proof of concept to estimate ̇ for both resting and PA.

Our results corroborate several previous studies in similar contexts in the literature. The accuracy of the ANN model to estimate ̇ was evaluated by [START_REF] Lin | Comparison of artificial neural network (ann) and partial least squares (pls) regression models for predicting respiratory ventilation: an exploratory study[END_REF] and [START_REF] Nyhan | Evaluating artificial neural networks for predicting minute ventilation and lung deposited dose in commuting cyclists[END_REF] during exercises performed by healthy subjects. Both studies reported that the ANN model achieved better performances compared to a partial least squares (PLS) model. [START_REF] Lin | Comparison of artificial neural network (ann) and partial least squares (pls) regression models for predicting respiratory ventilation: an exploratory study[END_REF] reported a mean difference of 0.9% between the reference ̇ from differential pressure pneumotachograph and the ANN estimations versus 7.1% with the PLS model. Similarly, [START_REF] Nyhan | Evaluating artificial neural networks for predicting minute ventilation and lung deposited dose in commuting cyclists[END_REF] found a smaller mean percentage error for ̇ with the ANN model (2.4%) as compared to the PLS model (5%). [START_REF] Raoufy | Nonlinear model for estimating respiratory volume bases on thoracoabdominal breathing movements[END_REF] compared two non-linear models for the estimation of respiratory volume based on thoracoabdominal distance variations: the ANN and the adaptive neuro-fuzzy inference system vs the MLR model. They showed that both non-linear models estimated ̇ variations that fitted the spirometer volume curves significantly (p<0.05) better than those with the linear methods. Recently, [START_REF] Dumond | Estimation of respiratory volume from thoracoabdominal breathing distances: comparison of two models of machine learning[END_REF] compared a linear MLR model and a non-linear ANN model to estimate respiratory volume. They found that the ANN model performed significantly better than the MLR model to estimate respiratory volume. The difference (bias) between respiratory volume measured by spirometer and estimated using RMP was higher for the MLR model (0.0019 ± 0.14 L) than for the ANN model (0.0015 ± 0.15 L). Indeed, physiological time series obtained from the cardiopulmonary system are non-stationary (Suki et al. 2003, Zhang and[START_REF] Zhang | Fractal characteristics of end-expiratory lung volume in anesthetized rats[END_REF] and are often associated with complex thoracoabdominal interactions, especially when respiratory movements are irregular [START_REF] Poole | Respiratory inductance plethysmography in healthy infants: a comparison of three calibration methods[END_REF][START_REF] Smith | Three degree of freedom description of movement of the human chest wall[END_REF][START_REF] Dumond | Estimation of respiratory volume from thoracoabdominal breathing distances: comparison of two models of machine learning[END_REF]. Therefore, a model that may be adapted to this type of non-linearity would be useful. Additionally, the comparison of the RMSE and bias between the two ANN approaches (ANNsp and ANNid) showed that the subject-specific approach (ANNsp) outperforms that of the subject-independent approach (ANNid). This is mainly due to the inter-subject variability: the non-linear relationship between deformations and minute volume changes from one subject to another. The ventilation response also differs between subjects due to the differences in elastic properties of the respiratory system, depending on the size and morphology of the subjects [START_REF] Chowdhuri | Control of ventilation in health and disease[END_REF]Badr 2017, Pinna et al. 2006). Thus, a subject-specific approach should be advised in the estimation of ̇ to maximize estimation accuracy. Our results were closely related to other studies, such as [START_REF] Liu | Improved regression models for ventilation estimation based on chest and abdomen movements[END_REF]. [START_REF] Gastinger | Estimates of ventilation from measurements of rib cage and abdominal distances: a portable device[END_REF] also suggested that mathematical equations must be developed for each subject to estimate ̇ from the RMP measurements.

Finally, whatever the model used, it seems that estimation errors always increase with physical intensities. These results are expected because of the greater range of ̇ during exercises of higher intensities. Furthermore, during intense PA, more movements occur that are not necessarily related to respiration [START_REF] Saunders | Postural and respiratory activation of the trunk muscles changes with mode and speed of locomotion[END_REF][START_REF] Dumond | Estimation of respiratory volume from thoracoabdominal breathing distances: comparison of two models of machine learning[END_REF], but could lead to increasing estimation errors.

Note that our study only covers the activities under laboratory conditions and restricted to structures of fixed durations. Future research efforts should include free-living PA of randomized orders and durations. Indeed, future RMP developments are expected to cater for remote monitoring under free-living conditions for patients with cardiovascular or pulmonary diseases. Such applications should include functions such as continuous assessment of respiratory functional status, and early-stage diagnosis of severe respiratory dysfunctions. These would require the use of simple, reliable, and reproducible methods across a variety of daily PA without specific subject cooperation by integrating more complex machine learning methods to deal with intra-and inter-subject variabilities.

Conclusion

We have proposed a novel method for ̇ estimation based on cycle-based features extracted from wearable RMP device under light-to-moderate PA. The combination of the non-linear ANN model with a subject-specific approach is shown to be more effective than the linear regression approach (MLR). Results also demonstrated the feasibility of individualized ̇ monitoring during different postures and PA conditions, paving the way for the more sophisticated energy expenditure estimation in various health monitoring applications for all PA types.

Figure 1 :

 1 Figure 1: Different stages for health monitoring using Sherpam system.

Figure 2 :Figure 3 :

 23 Figure 2: Illustration of the positions of RMP device.

Figure 4 :

 4 Figure 4: Artificial neural network architecture for ̇ estimation. ̇ : output of ANN model (minute ventilation estimated).

Figure 5 :

 5 Figure 5: Performance (RMSE) for the two ANN approaches: Comparison between ANNsp and ANNid. NS: non significant difference: p>0.05. *: significant difference: p<0.05. **: high significant difference: p<0.01.

Figure 6 :Figure 7 :

 67 Figure 6: Mean values of minute ventilation in l/min measured by spirometer and estimated by RMP. NS: non significant difference between ̇ and ̇ : p>0.05. *: significant difference between ̇ and ̇ : p<0.05. **: high significant difference between ̇ and ̇ : p<0.01.

Figure 8 :

 8 Figure 8: RMSE for the ANN and MLR model: Comparison between ANNsp and MLR model. NS: non significant difference: p>0.05. *: significant difference: p<0.05. **: high significant difference: p<0.01.

Figure 9 :

 9 Figure 9: RMSE as a function of the number of nodes in the hidden layer and the number of layers.

  NS: non significant difference between bias of the ANNsp and ANNid ( > 0.05). **: high significant difference between bias of the ANNsp and ANNid ( < 0.01). ##: highly significant difference between ANNsp and MLR.

	Table 1
	Mean differences between ̇	and ̇	.
	Activity		ANNsp (l/min)	ANNid (l/min)	MLR (l/min)
	Natural lying		-0.20 ± 0.87	-0.55 ± 2.13	4.17 ± 2.61 ##
	Natural standing		0.03 ± 1.13	0.36 ± 3.82	2.08 ± 3.99 ##
	Natural sitting		0.10 ± 0.99	-0.53 ± 3.69	3.89 ± 2.13 ##
	Metronome lying		-0.21 ± 1.10	-1.46 ± 3.11 **	-0.73 ± 3.19 ##
	Metronome standing	-0.19 ± 0.98	-1.23 ± 5.28 **	-2.09 ± 2.05 ##
	Metronome sitting	-0.17 ± 1.00	-0.57 ± 1.68 **	-1.15 ± 2.79 ##
	Working computer	-0.49 ± 1.34	-1.98 ± 2.07 **	-2.70 ± 2.92 ##
	Walking 4 km/h		0.22 ± 1.61	-0.76 ± 4.41 **	-1.42 ± 2.76 ##
	Walking 6 km/h		0.04 ± 1.76	-2.00 ± 4.98 **	-2.21 ± 3.32 ##
	Running 9 km/h		-0.03 ± 2.03	1.32 ± 5.63 **	1.60 ± 4.23 ##
	Running 12 km/h		0.78 ± 3.00	4.78 ± 7.23 **	2.77 ± 4.89 ##
	Biking 90 W		0.02 ± 2.23	-0.55 ± 6.75	1.33 ± 4.51 ##
	Biking 110 W		-0.38 ± 2.47	-2.07 ± 7.21 **	-2.12 ± 4.84 ##

J o u r n a l P r e -p r o o f

Acknowledgements

The authors wish to acknowledge all subjects for their participation in the study. This work was conducted as part of the SHERPAM (Sensors for Health Recording and Physical Activity Monitoring) project (2014)(2015)(2016)(2017)(2018). As such, it received support from the French government granted to the ComniLabs Laboratory of Excellence, and managed by the National Research Agency as part of the Investing for the Future Program (reference ANR-10-LABX-07-01). Further information about this project can be found at ( https://project.inria.fr/sherpam/).

Conflict of Interest

There are no conflicts of interest regarding this research.

J o u r n a l P r e -p r o o f


Sébastien Villotte

Laurent Crépin
email: laurent.crepin@mnhn.fr

Mathieu Rué
email: mathieu.rue@paleotime.fr

Emmy Bocaege
email: e.bocaege@kent.ac.uk

Mona Le Luyer
email: m.le-luyer@kent.ac.uk

Stéphane Madelaine
email: stephane.madelaine@culture.gouv.fr

Jean-Baptiste Caverne
email: jean-baptiste.caverne@laposte.net

André Morala
email: andre.morala@orange.fr

Sebastien Villotte
email: sebastien.villotte@u-bordeaux.fr

Sebastien Villotte

Valentina Mariotti

Bruno Maureille

Silvia Bello

Erik Trinkaus

Hélène Rougier

Sébastien Villotte

Mathieu

Evidence for previously unknown mortuary practices in the Southwest of France (Fournol, Lot) during the Gravettian

Keywords: Mortuary practices, Mid Upper Paleolithic, post-mortem treatment, cut marks, Cannibalism Mortuary practices, Mid Upper Paleolithic, post-mortem treatment, cut marks, Cannibalism. 1 Introduction

à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Tables.docx [Table] To view all the submission files, including those not included in the PDF, click on the manuscript title on your EVISE Homepage, then click 'Download zip file'. The European Mid Upper Paleolithic (MUP, ca. 30-20 000 BP or 34-24 000 calBP) is well known for the so-called "red ochre burials" across Europe and is mostly (but not only) associated with the Gravettian culture [START_REF] Mussi | Earliest Italy: an overview of the Italian Paleolithic and Mesolithic[END_REF][START_REF] Henry-Gambier | Comportement des populations d'Europe au Gravettien : Pratiques funéraires et interprétations[END_REF][START_REF] Riel-Salvatore | Upper Palaeolithic Mortuary Practices in Eurasia: A Critical Look at the Burial Record[END_REF][START_REF] Trinkaus | The People of Sunghir. Burials, Bodies, and Behavior in the Earlier Upper Paleolithic[END_REF][START_REF] Reynolds | The Kostënki 18 child burial and the cultural and funerary landscape of Mid Upper Palaeolithic European Russia[END_REF]. Until recently, all the securely dated MUP burials which were sufficiently preserved to allow interpretations of the mortuary practices have been considered as primary deposits [START_REF] Henry-Gambier | Comportement des populations d'Europe au Gravettien : Pratiques funéraires et interprétations[END_REF]. Post-mortem manipulations of the body (apart from pierced teeth, see [START_REF] Vercoutère | Une dent humaine perforée découverte en contexte Gravettien ancien à l'abri Pataud (Dordogne, France)[END_REF] were not known for this period. However, recent discoveries and reanalyses significantly modified this paradigm.

A recent reanalysis of the burial practices at Sunghir (Vladimir Oblast, Russia) indicated that an isolated adult femur was intentionally placed within the grave of two immature individuals [START_REF] Trinkaus | The People of Sunghir. Burials, Bodies, and Behavior in the Earlier Upper Paleolithic[END_REF][START_REF] Trinkaus | Diversity and differential disposal of the dead at Sunghir[END_REF]. The left forearm and hand of one of these individuals (Sunghir 2) had been noted as missing during the excavation, implying a potential prehistoric human postdepositional intervention [START_REF] Trinkaus | The People of Sunghir. Burials, Bodies, and Behavior in the Earlier Upper Paleolithic[END_REF][START_REF] Trinkaus | Diversity and differential disposal of the dead at Sunghir[END_REF]. At Paglicci (Apulia, Italy), the left humerus of an adolescent buried with grave goods and ornaments (PAII) is missing [START_REF] Ronchitelli | When technology joins symbolic behaviour: the Gravettian burials at grotta Paglicci (Rignano Garganico-Foggia-Southern Italy)[END_REF], suggesting a similar post-depositional intervention. At Pavlov I (Moravia, Czech Republic), one pair of hands and two pairs of feet, disassociated from any distal long bones, have been interpreted as indicators of cultural treatment of the individuals' remains [START_REF] Trinkaus | Human remains from the Moravian Gravettian: morphology and taphonomy of additional elements from Dolní Vĕstonice II and Pavlov I[END_REF][START_REF] Trinkaus | Palmar, Patellar, and Pedal Human Remains from Pavlov[END_REF]. At Buran-Kaya III (Crimea), fragmented human remains with cut marks were recently discovered in several archeological layers associated with the Gravettian techno-complex [START_REF] Prat | The Oldest Anatomically Modern Humans from Far Southeast Europe: Direct Dating, Culture and Behavior[END_REF][START_REF] Yanevich | Les occupations gravettiennes de Buran-Kaya III (Crimée) : contexte archéologique[END_REF][START_REF] Crépin | Contribution of taphonomy of human and faunal remains to the understanding of mortuary practices of Gravettians from far south-eastern Europe : Level 6-1 of Buran-Kaya III (Crimea)[END_REF]). These were the first ever cut marks reported so far for MUP human remains and have been interpreted as the result of a mortuary ritual (either specific mortuary practices or a ritual cannibalism).

Apart from these examples from Central and Eastern Europe, most of the evidence for MUP postmortem manipulations comes from one region: the Southwest of France. At Pataud (Dordogne), the Late Gravettian human remains from layer 2 (minimum number of individuals (MNI) of 6) had a complex post-mortem history involving secondary deposits, displacement of cranial remains, and removal of some long bones [START_REF] Chiotti | Une nouvelle fouille à l'abri Pataud[END_REF]Henry-Gambier et al., 2013a). At Cro-Magnon (Dordogne), now securely dated to the Early Gravettian, the human remains (MNI=5) were likely not buried, but instead deposited in the back of the shelter [START_REF] Henry-Gambier | Les fossiles de Cro-Magnon (Les eyzies-de-Tayac, Dordogne) : nouvelles données sur leur position chronologique et leur attribution culturelle[END_REF]Henry-Gambier et al., 2013a, 2013b). At Cussac (Dordogne), a Middle Gravettian decorated cave, human remains (MNI=6) were not buried in the ground, but deposited in bear nests and some bones (including five crania) are apparently missing (Henry-Gambier et al., 2013c;[START_REF] Jaubert | The chronology of human and animal presence in the decorated and sepulchral cave of Cussac (France)[END_REF][START_REF] Peignaux | New Anthropological Data from Cussac Cave (Gravettian, Dordogne, France): In Situ and Virtual Analyses of Locus 3[END_REF]. At Gargas (Hautes-Pyrénées), several human remains, including an isolated juvenile mandible and adult femur (both directly dated to ca. 25,000 14 C years BP) were recovered from the Gravettian layers close to decorated walls [START_REF] Foucher | Les vestiges humains gravettiens de la grotte de Gargas (Aventignan, France): datations 14C AMS directes et contexte chrono-culturel[END_REF]. In addition to this, some of the human remains from Gargas were covered with a thin calcite layer, suggesting they were also deposited on the surface [START_REF] Foucher | Les vestiges humains gravettiens de la grotte de Gargas (Aventignan, France): datations 14C AMS directes et contexte chrono-culturel[END_REF]. Finally, at Vilhonneur (Charente), human remains (cranium, ribs, vertebrae, sacrum, left and right os coxae, left and right femora and tibiae) of a young adult (directly dated to ca. 27,000 14 C years BP) were found scattered on the floor of a decorated cave [START_REF] Henry-Gambier | New hominid remains associated with gravettian parietal art (Les Garennes, Vilhonneur, France)[END_REF].

To summarize, the Gravettian human remains from the Southwest of France seem to be associated to mortuary practices that contrast greatly with the general idea of MUP primary burials where one, two or three individuals were buried with ochre, body ornaments and grave goods [START_REF] Mussi | Earliest Italy: an overview of the Italian Paleolithic and Mesolithic[END_REF][START_REF] Henry-Gambier | Comportement des populations d'Europe au Gravettien : Pratiques funéraires et interprétations[END_REF]). Here we present the preliminarily results of the anthropological study of Fournol (Soturac, Lot, France) (Fig. 1). We provide evidence for a previously unknown Gravettian post-mortem treatment in the Southwest of France. Figure 1. Location of the site and schematic illustration of the excavation area. Data source of the colorized digital elevation model: SRTM, 1 Arc-Second Global. Authors: MR and JBC. 2 The Fournol rock shelter Fournol is a relatively small rock shelter (ca. 10 meters long and 3 meters depth), open to the south (Fig. 1) and developed into Coniacian limestone 162 m a.s.l. (above seal level). This prehistoric site was likely known at the beginning of the last century, as in 1908, the Museum of Toulouse received a number of excavated prehistoric remains from this site (Morala, pers. obs.). After World War II, the site was occasionally excavated again, but the nature and location of the recovered material are unknown [START_REF] Morala | Soturac (Lot) -Les Ardailloux et Couvert[END_REF][START_REF] Morala | Périgordien et Aurignacien en Haut-Agenais : Etude d'ensembles lithiques[END_REF][START_REF] Morala | Soturac. Fournol (Lot). Bilan scientifique 2015 -Direction Régionale des Affaires Culturelles Midi-Pyrénées[END_REF]. One of us (AM) did surface prospecting at Fournol in the 70's and 80's. Typological and technological analyses of the lithic material found at the site identified two chronocultures of the Upper Paleolithic: the Middle Gravettian and the Early Solutrean [START_REF] Morala | Soturac (Lot) -Les Ardailloux et Couvert[END_REF][START_REF] Morala | Périgordien et Aurignacien en Haut-Agenais : Etude d'ensembles lithiques[END_REF]. An isolated human tooth was also discovered during this surface prospecting.

Between 2000 and 2005, clandestine excavations were carried out at the site. In 2012, at least a part of the illegally excavated material was seized by the Gendarmerie of Villeneuve-sur-Lot. The confiscated material (lithic artifacts and human and faunal remains) was then acquired by the Musée national de Préhistoire. The lithic material can be typologically assigned to the Middle Gravettian [START_REF] Morala | Abri de Fournol, Soturac, Lot[END_REF]. A direct date was obtained from a frontal bone fragment displaying anthropic marks (i.e. cut marks). The result of 24 820 ± 220 BP (Lyon-9985 SacA 32610) [START_REF] Morala | Abri de Fournol, Soturac, Lot[END_REF] falls within the age range for the Middle Gravettian in the Southwest of France (e.g. [START_REF] Klaric | Regional groups in the European Middle Gravettian: a reconsideration of the Rayssian technology[END_REF].

From 2015 onwards, several excavation seasons took place, led by one of us (AM) and funded by the Ministry of Culture and Communication. The degree of deterioration caused by the last clandestine excavations was evaluated (Fig. 1). At the front of the shelter, a large trench (nearly 5m long to a depth of 50-80 cm) had been dug by the looter(s) with the excavated sediment (including archaeological material) thrown inside the shelter and retained by a dry stone wall [START_REF] Morala | Soturac. Fournol (Lot). Bilan scientifique 2015 -Direction Régionale des Affaires Culturelles Midi-Pyrénées[END_REF]. Three main geoarcheological units have been identified so far within and in front of the rock shelter, with a 15° to 5° slope to the outside. Unit 1 is formed by a dark brown, carbonated sandy loam matrix with limestone clasts (gravels to blocks). This unit is several decimeters thick (possibly close to one meter in some areas), and was highly disturbed, both by bioturbation and by the previous illicit excavations. Faunal and human remains, as well as lithic material characteristic of the Middle Gravettian, were found in this unit [START_REF] Morala | Soturac. Fournol (Lot). Bilan scientifique 2015 -Direction Régionale des Affaires Culturelles Midi-Pyrénées[END_REF]. The artifact assemblage seemed homogenous, apart from a few modern artifacts (some glass shards and small metallic fragments) likely related to the previous excavations, and no evidence of intermixture between archeological layers from different cultures was found. Unit 2, below Unit 1, is composed of limestone clasts in a yellowish loamy sand carbonated matrix, and was much thinner than Unit 1 (0 to 20 cm). Less archeological material (and no human remains) were found in this unit. The analysis of the lithic material points toward one or several Late Aurignacian occupation(s). Unit 3 corresponds to limestone clasts in a yellowish loamy sand cemented matrix (breccia). This phase of calcitic cementation had affected different deposits including a residual coating preserved against the wall of the shelter with Early Solutrean artifacts.

Material and methods

The human remains from the looter's collection and from the recent excavation campaigns were first studied by Dominique Henry-Gambier, and then by four of us (SV, LC, EB, MLL). Here, we present the results of the anthropological and taphonomical analyses of the human remains from the looter collection and those discovered during the archeological field seasons of 2015, 2016 and 2017. A total of 127 skeletal remains were identified as probably or certainly human (table 1). One was discovered in 1986, 45 are from the looter's collection and the other remains were excavated during the three campaigns from 2015 to 2017 (respectively 32, 29 and 20 skeletal remains). All of the remains discovered during the excavations were found in the Unit 1, spread over 24m² (but 73% of them derive from 9m²). The majority of the human remains (110, 86.6%) are fragmented, while only 17 remains are complete (including 15 teeth). The maximum preserved length is very small on average (26 mm) and inferior to 40 mm for 90% of the assemblage. Teeth are the most common elements (28.3%), followed by bones from the hand (23.6%) and neurocranial fragments (18.9%) (Table 1).

A part of the human remains (21.3%, mostly teeth) was clearly identified as juvenile. The remaining skeletal and dental elements (78.7%) were considered adult. However, it is worthwhile mentioning that, considering the high degree of fragmentation of the bones, the skeletal maturity cannot be ascertained with complete confidence for a significant part of the remains. It is thus possible that the percentage of adult remains is actually inflated. Because of the small size of the fragments, systematic refitting, probable re-association and exclusion was attempted only for the teeth. At least six individuals were identified from the dental remains, including three juveniles and three adults. Individuals were identified based on the presence of duplicate elements, dental morphology, dental developmental stages and wear patterns. We did not attempt to assess the sex of the individuals or the age at death of the adult bone fragments due to the very important degree of fragmentation. We did not attempt to estimate the age-at-death of the adults based on the degree of tooth wear due to the many factors that can influence this phenomenon. The age-at-death of the three identified juveniles were estimated to be 4-8, 6-10 and 8- The taphonomic analysis of the anthropological sample was carried out visually, using a magnifying glass and a light microscope (x10 -x60). Taphonomic modifications were recorded and tentatively linked to specific taphonomic processes and agents following Binford, (1981), [START_REF] Potts | Cutmarks made by stone tools on bones from olduvai Gorge, Tanzania[END_REF], [START_REF] Behrensmeyer | Trampling as a cause of bone surface damage and pseudo-cutmarks[END_REF], [START_REF] Reitz | Zooarchaeology[END_REF][START_REF] Reitz | Zooarchaeology[END_REF][START_REF] Fernández-Jalvo | Atlas of Taphonomic Identification[END_REF][START_REF] Fernández-Jalvo | Atlas of Taphonomic Identification[END_REF]. In this article, we focus on the peri-mortem anthropic modifications such as cut marks or bone breakage. Fracture morphologies (fracture outline, angle, edge and the extent of survivorship of the shaft circumference of long bones) were recorded following [START_REF] Villa | Breakage patterns of human long bones[END_REF]. Fractures with smooth textures, an oblique fracture angle and a curved or spiral outline usually occur on green bone (e.g. [START_REF] Binford | Bones. Ancient Men and Modern Myths[END_REF][START_REF] Villa | Breakage patterns of human long bones[END_REF][START_REF] Fernández-Jalvo | Atlas of Taphonomic Identification[END_REF]. The morphological properties of the linear marks (trajectory of the groove, its orientation relative to the axis of the bone, its position, and the section profile, symmetry, length and depth of the groove), as well as the presence or absence of structural features inside (internal microstriations) or close to (shoulder effect) the grooves were recorded following [START_REF] Bello | A new method for the quantitative analysis of cutmark micromorphology[END_REF], [START_REF] Domínguez-Rodrigo | A new protocol to differentiate trampling marks from butchery cut marks[END_REF] and Fernández-Jalvo and Andrews (2016). Many organic and inorganic processes can produce linear marks on bones, the main problem being the possible confusion between superficial traces on bone produced by trampling and those made during butchering. Some trampling marks can show similarities to butchery marks (e.g. Andrews and Cook, 1985;[START_REF] Behrensmeyer | Trampling as a cause of bone surface damage and pseudo-cutmarks[END_REF], but they can usually be differentiated when the following discriminating variables are applied jointly (e.g. [START_REF] Olsen | Surface modification to bone: trampling versus butchery[END_REF][START_REF] Domínguez-Rodrigo | A new protocol to differentiate trampling marks from butchery cut marks[END_REF]: -cut marks are usually deeper and longer than trampling marks; -cut marks tend to have more frequently than trampling marks an asymmetrical V-shaped cross section; -the groove trajectory of cut marks is straight most of the time whereas trampling marks tend to be sinuous; -the shoulder effect tends to be more common in cut marks than in trampling marks. Trampling marks also tend to be randomly placed whereas cut marks occur preferentially in anatomically meaningful locations (e.g. [START_REF] Binford | Bones. Ancient Men and Modern Myths[END_REF]Andrews and Cook, 1985;[START_REF] Olsen | Surface modification to bone: trampling versus butchery[END_REF][START_REF] Lyman | Vertebrate taphonomy[END_REF][START_REF] Reitz | Zooarchaeology[END_REF][START_REF] Fernández-Jalvo | Atlas of Taphonomic Identification[END_REF]. The superimposition and succession of marks caused by different post-depositional processes and agents (humans, plant roots, trampling, calcitic concretion, etc.) were taken into account in order to attest the antiquity of the anthropic marks analyzed here. Only unequivocal ancient evidence of human-induced linear marks were considered for the present study.

Results

At least 30 skeletal elements (23.6 % of the assemblage) displayed striations very likely made with lithic tools (Table 1). When isolated teeth are excluded, this percentage increases to 30.8% of the assemblage (28/91). Interestingly, no clear evidence of other human induced modifications, such as peri-mortem breakage, were observed on the human remains. Cut marks were recorded on 26 adult skeletal remains (26.0% of the adult assemblage), the vast majority of these were found on the cranial remains, the bones of the pectoral girdle and the hand. Half of the adult neurocranial fragments exhibit cut marks. For example, the frontal remains (RH-084) showed several groups of parallel marks with microstriations and shoulder effects (Fig. 2). They are quite short (7-10 mm) and superficial, presenting the same patina as the bone and mostly covered by calcite concretion. A right temporal bone fragment (RH-004), showed several very fine and short (1-3 mm) and longer (5-9 mm) cut marks in three different directions around the mandibular fossa. Figure 2. Cut marks on the external surface of a human frontal fragment (RH-084) from Fournol (scale: 10 mm). From top to bottom: picture of the external surface of the fragment, sketch with cut marks highlighted in red, and close-up view (not to scale) of the framed area. Photographs: AM and Maryelle Bessou, sketch: LC. One of the best preserved bones in the sample is a right corpus and ramus of an adult mandible (RH-001) with more than twenty cut marks, located on both surfaces and ranging from 2 to 15 mm (Fig. 3). The majority of these cuts are on the ramus, but some are also present on the external surface of the body. They are almost all parallel, continuous, more or less deep and clear, and arranged in small groups. Most of the marks seem to be located on the attachment sites of the lateral pterygoid muscle, the capsule, and the associated ligaments. Figure 3. Cut marks on the external (left) and internal (right) surface of a human hemi-mandible (RH-001) from Fournol (scale: 10 mm). From top to bottom: pictures of the fragment, sketches with cut marks highlighted in red, and close-up views (not to scale) of the framed areas. Photographs: AM and Maryelle Bessou, sketches: LC and SV. One of the two teeth displaying cut marks, the first right premolar (RH-002), refits with the mandible RH-001. The oblique linear marks are visible on the vestibular surface of the crown in two locations (Fig. 4). Figure 4. Cut marks on the vestibular aspect of a human premolar (RH-002) from Fournol (scale: 10 mm). Top: picture of the tooth and sketch with cut marks highlighted in red. Bottom: close-up view (not to scale) of the framed area. Photographs: Maryelle Bessou, sketch: VL. Three adult clavicular fragments display cut marks on their diaphyses. For instance, RH-012 (left clavicle) shows four fine, short and oblique cut marks on its inferior surface. Its anterior surface presents many more anthropic marks with ca. 16 very short (3-4 mm), deep and parallel marks (with shoulder effects and microstriations) along the diaphysis (Fig. 5). They are covered by reddish and/or calcified sediment. These incisions are located at the attachment site of the deltoid muscle. Cut marks on the other adult clavicular fragments are also short and parallel, done transversally or obliquely to the long axis of the bones on one or two directions maximum. Figure 5. Cut marks on the inferior and anterior surfaces of a human left clavicle (RH-012) from Fournol (scale: 10 mm). From top to bottom: picture of the inferior surface of the fragment, sketch with cut marks highlighted in red, and close-up view (not to scale) of the framed area. Photographs: AM, sketch: LC. Human modifications are also visible on three hand phalanges and two metacarpal fragments. Cut marks are principally located on the palmar surface except for one intermediate phalanx (RH-017), where they were found on one side (Fig. 6). These marks are short, deep and parallel, grouped by two or three at maximum, and appear transversally to the long axis of the bone. Figure 6. Cut marks on the palmar and lateral surfaces of a human phalanx (RH-017) from Fournol (scale: 10 mm). Top: palmar view, bottom: lateral view. From right to left: picture of the surface of the fragment, sketch with cut marks highlighted in red, and close-up view (not to scale) of the framed area. Photographs: AM, sketch: LC. Only four elements (one neurocranial fragment, one molar, one radial fragment and one clavicular fragment) displaying cut marks are from immature individual(s). On the radial (RH-020) and right clavicular (RH-015) fragments, the cut marks seem to correspond to one single event characterized by two to four short (2 to 5 mm long), fine and parallel striations appearing transversally to the long axis of the bone. The cut marks on the molar (RH-119) are short, sub-horizontal, and located close to the cervix on the mesio-vestibular aspect of the crown. 5 Discussions and conclusions Isolated human remains are known from a variety of Gravettian sites, both with and without formal burials (e.g. [START_REF] Mallegni | Les restes hunains découverts dans les niveaux gravettiens de la grotte Paglicci (Rignano Garganico, Pouilles, Italie)[END_REF][START_REF] Trinkaus | Human remains from the Moravian Gravettian: morphology and taphonomy of additional elements from Dolní Vĕstonice II and Pavlov I[END_REF][START_REF] Trinkaus | The People of Sunghir. Burials, Bodies, and Behavior in the Earlier Upper Paleolithic[END_REF][START_REF] Foucher | Les vestiges humains gravettiens de la grotte de Gargas (Aventignan, France): datations 14C AMS directes et contexte chrono-culturel[END_REF]. The taphonomic histories of most of these remains are unclear, but their presence at sites with ritual burials (e.g. Paglicci, Dolní Vĕstonice, Sunghir) has raised questions as to why the remains of some but not all people were formally buried. In the Southwest of France, the situation is quite different: formal Gravettian burials are unknown and there is substantial evidence for the depositing of the body on rather than in the ground as well as the displacement of body parts and the removal of long bones and crania (Henry-Gambier et al., 2013a, 2013c;[START_REF] Foucher | Les vestiges humains gravettiens de la grotte de Gargas (Aventignan, France): datations 14C AMS directes et contexte chrono-culturel[END_REF]. Cut marks on human remains have not been described previously for this time period in this region. The anthropogenic nature of the marks seen at Fournol is attested by the frequency of surfaces displaying several parallel incisions as well as the morphology and the anatomically meaningful location of the marks. One of the remains with anthropogenic marks has been directly dated to the Middle Gravettian, which is consistent with the typotechnological characterization of the lithic material both from the looters' collection and Unit 1. Thus, despite disturbances, there are strong arguments to consider all the human remains discovered so far as a chronologically homogenous assemblage dated to the Middle Gravettian. Future work will involve obtaining more direct 14C dates for the individuals represented in the assemblage. The interpretation of the anthropic marks recorded on the human skeletal assemblage is hindered by the small size of the fragments and the difficulty in attributing the bones to separate individuals. However, it is likely that most of the marks on the neurocranial fragments are associated with skinning, because this would involve repeated strokes, resulting in a series of striations. It is likely that the right temporal bone RH-004 and the condylar process of the mandible RH-001 belong to the same individual and the marks on these elements can be tentatively interpreted as the result of the disarticulation of the temporomandibular joint. Labial cut marks on teeth are relatively frequent in the fossil record and have been associated to the so-called "stuff and cut" behavior. However, these marks are overwhelmingly found on in very large quantities on anterior teeth and spread throughout the labial aspect of the crown (e.g. [START_REF] Fox | Cutmarks and post-mortem striations in fossil human teeth[END_REF][START_REF] Volpato | Hand to mouth in a neandertal: right-handedness in Regourdou 1[END_REF], whereas at Fournol, the cut marks are visible on the vestibular aspect of a premolar and a molar, on a small surface relatively close to the cervix. By analogy with zooarcheological studies (e.g. [START_REF] Soulier | Hominid subsistence strategies in the South-West of France: A new look at the early Upper Palaeolithic faunal material from Roc-de-Combe (Lot, France)[END_REF][START_REF] Mallye | Large carnivores and small games use from the Early Aurignacian of La Quina aval (Charente, France) (V. Dujardin excavations)[END_REF], these marks can be tentatively associated with the skinning of the head. Finally, the cut marks on the pectoral girdle and the phalanges of the hand seem to be mainly related to disarticulation of joints. There are at least two (not mutually exclusive, see for instance [START_REF] Belcastro | Funerary practices of the Iberomaurusian population of Taforalt (Tafoughalt, Morocco, 11-12,000 BP): the case of Grave XII[END_REF] scenarios to account for the human bone assemblage discovered so far at Fournol: cannibalism, or/and specific mortuary rites. The frequency of human remains with cut marks, which is relatively high (ca. 24%) at Fournol, is in the range of variation of what is seen in assemblages for which cannibalism has been considered as probable (Table 2). However, cannibalism was also inferred from other anthropic modifications identified in these sites, including scrape marks, tooth marks, destruction of vertebral bodies and long bone extremities, etc. for which evidence is currently lacking at Fournol. To infer the practice of cannibalism solely based on the relative high frequency of cut marks seen in this assemblage is therefore highly problematic. Moreover, the presence of residual red pigment on some human bones displaying cut marks (e.g. Fig. 3 and5) may indicate a complex post-mortem treatment of the bodies involving dismemberment, skinning and defleshing of the cadaver, as well as the use of pigments. The (limited) skeletal representation of the current assemblage from Fournol is likely related, at least in part, to previous looting practices, as part of the looted material may have been sold or kept in personal collections. However, it might also be possible that the very partial skeletal representation (a minimum number of individuals of six) and the overrepresentation of metacarpals and manual phalanges indicates a specific focus on some parts of the body, namely the head and the hands. Interestingly, most of the hand prints and stencils in European cave art, some characterized by missing or partial fingers, are thought to be Gravettian (e.g. Jaubert 2008; Lorblanchet, 2010; but see [START_REF] Pettitt | Are hand stencils in European cave art older than we think? An evaluation of the existing data and their potential implications[END_REF]. The importance of hands and fingers during the MUP is also illustrated by the isolated pair of hands at Pavlov I [START_REF] Trinkaus | Human remains from the Moravian Gravettian: morphology and taphonomy of additional elements from Dolní Vĕstonice II and Pavlov I[END_REF][START_REF] Trinkaus | Palmar, Patellar, and Pedal Human Remains from Pavlov[END_REF] and the discovery of two isolated manual phalanges close to a boomerang at Obłazowa Cave [START_REF] Valde-Nowak | ObŁazowa and HŁomcza: Two Paleolithic Sites in the North Carparthians Province of Southern Poland[END_REF]. Further analyses, as well as increasing the sample size of the assemblage through continued excavation, are required in order to identify the most likely scenario resulting in the observed cut marks. Microscopic studies will be carried out in order to better characterize the direction and the movement of the marks, and will help to get a better understanding of the practices resulting in these marks. The systematic study of ochre distribution on the skeletal remains will allow a discussion as to whether the coloration was carried out on disarticulated and defleshed bones. Finally, comparative taphonomic analysis of the faunal and human remains (e.g. [START_REF] Mussini | ): étude morphométrique et réflexions sur un aspect comportemental des Néandertaliens[END_REF][START_REF] Prat | The Oldest Anatomically Modern Humans from Far Southeast Europe: Direct Dating, Culture and Behavior[END_REF][START_REF] Rougier | Neandertal cannibalism and Neandertal bones used as tools in Northern Europe[END_REF] may allow the identification of a specific mortuary treatment of the human cadavers at this site. To conclude, the evidence from Fournol, although limited in scope, suggests that the treatment of human bodies during the MUP was much more diversified than previously thought, and that Gravettian mortuary practices in the Southwest of France clearly deviate from the main pattern observed elsewhere, i.e. the primary burials associating one or several individuals, ochre, body ornaments and grave goods. 6 Acknowledgments SV thanks Dominique Henry-Gambier (UMR 5199 PACEA, Université de Bordeaux -CNRS) for giving him the opportunity to study these fossils. The authors thank the curators of the MNP who allowed access to a part of the material, Jean-Paul Bayle, the owner of the site, for granting the right to excavate and study the material, and the Service Regional d'Archéologie of Occitanie. The authors also thank the three reviewers for their useful comments, and Maryelle Bessou (UMR 5199 PACEA, Université de Bordeaux -CNRS) for the close-up images of the remains. 7 Funding This work was supported by the Agence Nationale de la Recherche (ANR) GRAVETT'OS (grant number ANR-15-CE-0004). EB's work was supported by a British Academy Postdoctoral Fellowship. MLL's was supported by a Marie Skłodowska-Curie Individual Fellowship (grant agreement n°796499). Excavation campaigns at Fournol are funded by the French Ministry of Culture and Communication. 8 References cited AlQahtani, S.J., Hector, M.P., Liversidge, H.M., 2010. Brief communication: The London atlas of human tooth development and eruption. American Journal of Physical Anthropology. 142, 481-490. Andrews, P., Cook, J., 1985. Natural modifications to bones in a temperate setting. Man, 675-691.

Fig

  Fig 1 new.tif [Figure] Fig 2 fu OK.tif [Figure] Fig 3 OK fu.tif [Figure] Fig 4 fu.tif [Figure]

Fig 5

 5 Fig 5 OK fu.tif [Figure]

Fig 6

 6 Fig 6 OK Fu.tif [Figure]

Table 1 .

 1 Summary of human remains from Fournol and number of modified elements. N: Number of fragments.

			Adult		Juvenile		Total
	Skeletal element	N	N with cut marks	N	N with cut marks	N	N with cut marks	% with cut marks
	Skull (without mandible)	23	12	2	1	25	13	52.0%
	Mandible	2	2	0	0	2	2	100.0%
	Isolated tooth	16	1	20	1	36	2	5.6%
	Vertebra	7	0	0	0	7	0	0.0%
	Rib	5	0	0	0	5	0	0.0%
	Clavicle	5	3	2	1	7	4	57.1%
	Scapula	2	2	0	0	2	2	100.0%
	Radius	0	0	1	1	1	1	100.0%
	Ulna	2	0	0	0	2	0	0.0%
	Metacarpal	6	2	0	0	6	2	33.3%
	Hand phalanx	23	3	1	0	24	3	12.5%
	Femur	4	1	0	0	4	1	25.0%
	Tibia	3	0	0	0	3	0	0.0%
	Fibula	1	0	1	0	2	0	0.0%
	Pedal phalanx	1	0	0	0	1	0	0.0%
	Total	100	26	27	4	127	30	23.6%

years, based on dental developmental stages (AlQahtani et al. 2010).

Submission Files Included in this PDF