Maternal mental health and memory (re)consolidation following a traumatic childbirth

Objectives: The overall aim of this thesis was to contribute to the development of clinical interventions to prevent or reduce maternal symptoms of childbirth-related post-traumatic stress disorder (CB-PTSD). To do so, it relied on the literature on memory (re)consolidation, which corresponds to a set of processes potentially involved in the development and maintenance of CB-PTSD. The ambition of this thesis was to translate the research on memory (re)consolidation, mainly based on laboratory studies, into applied clinical proposals. Several avenues were explored: 1. Identifying factors that may modulate the consolidation of the traumatic birth memory (TBM) such as prenatal insomnia symptoms (Study 1), administration of nitrous oxide gas (N2O) or morphine during childbirth (Study 2), and CB-PTSD symptoms; and 2. Testing the effectiveness of brief visuospatial task-based interventions, which are assumed to interfere with the (re)consolidation of the TBM, in preventing (Study 3) or reducing (Study 4) CB-PTSD symptoms. Methods: Studies 1 (n = 1,610) and 2 (n = 2,070) were based on a prospective population-based cohort study (secondary data analyses), following women from pregnancy to eight weeks postpartum. Variables were measured via self-report questionnaires and patients' medical records. CB-PTSD was assessed at eight weeks postpartum. Study 3 (n = 144) is an ongoing multicentre, double-blind, randomised controlled trial (thus, results are not available yet). The intervention tested is delivered within six hours postpartum, and its effectiveness is primarily measured by a childbirth-related intrusive traumatic memories (ITMs) diary over the first week postpartum and an assessment of CB-PTSD symptoms at six weeks postpartum. Finally, Study 4 (n = 18) was a single-group pre-post study. The benefits of the intervention were measured with an ITMs diary over two weeks before and six weeks after the intervention, and CB-PTSD symptoms were measured with a self-report questionnaire, five days before and one month after the intervention. Results: In Study 1, prenatal insomnia symptoms were associated with CB-PTSD symptom severity, and this relationship was fully mediated by a negative subjective birth experience, as well as by postnatal insomnia symptoms. In Study 2, N2O administration during childbirth predicted less severe CB-PTSD symptoms. This was marginally the case with morphine. However, both analgesics predicted more CB-PTSD symptoms when combined with very severe pain during childbirth. Finally, participants in Study 4 reported a large reduction in their number of ITMs, and it persisted for up to six weeks post-intervention. Their CB-PTSD symptoms were also greatly reduced. Clinical implications: The results of this thesis suggest a number of avenues for preventing or reducing CB-PTSD symptoms through brief, simple, cost-effective, and innovative interventions. These could potentially be implemented throughout the perinatal period and notably pave the way for pharmacological (Study 2) or psychological (Studies 1 and 3) strategies for CB-PTSD prevention, for which there is currently no evidence-based intervention

Multi-core software architecture for the scalable HEVC decoder

International audienceThe scalable high efficiency video coding (SHVC) standard aims to provide features of temporal, spatial and quality scalability. In this paper we investigate a pipeline and parallel software architecture for the SHVC decoder. The proposed architecture is based on the OpenHEVC software which implements the high efficiency video coding (HEVC) decoder. The architecture of the SHVC decoder enables two levels of parallelism. The first level decodes the base layer and the enhancement layers in parallel. The second level of parallelism performs the decoding of both the base layer and enhancement layers in parallel through the HEVC high level parallel processing solutions, including tile and wavefront. Up to the best of our knowledge, it is the first real time and parallel software implementation of the SHVC decoder. On an Intel Xeon processor running at 3.2 GHz, the SHVC decoder reaches the decoding of 1600p enhancement layer at 40 fps for x1.5 spatial scalability with using six concurent threads

Quality constraint and rate-distortion optimization for predictive image coders

International audienceNext generations of image and video coding methods should of course be efficient in terms of compression, but also propose advanced functionalities. Among these functionalities such as scalability, lossy and lossless coding, data protection, Rate Distortion Optimization (RDO) and Rate Control (RC) are key issues. RDO aims at optimizing compression performances, while RC mechanism enables to exactly compress at a given rate. A less common functionality than RC, but certainly more helpful, is Quality Control (QC): the constraint is here given by the quality. In this paper, we introduce a joint solution for RDO and QC applied to a still image codec called Locally Adaptive Resolution (LAR), providing scalability both in resolution and SNR and based on a multi-resolution structure. The technique does not require any additional encoding pass. It relies on a modeling and estimation of the prediction errors obtained in an early work. First, quality constraint is applied and propagated through the whole resolution levels called pyramid. Then, the quantization parameters are deduced considering inter and intra pyramid level relationships. Results show that performances of the proposed method are very close to an exhaustive search solution

Parallel SHVC decoder: Implementation and analysis

International audienceThe new Scalable High efficiency Video Coding (SHVC) standard is based on a multi-loop coding structure which requires the total decoding of all intermediate layers. The decoding complexity becomes then a real issue, especially for a real time decoding of ultra high video resolutions. A parallel processing architecture is proposed to reduce both the decoding time and the latency of the SHVC decoder. The proposed solution combines the high level parallel processing solutions defined in the HEVC standard with an extension of the frame-based parallelism. The latter solution enables the decoding of several spatial and temporal SHVC frames in parallel to enhance both decoding frame rate and latency. The wavefront parallel processing solution is used for more coarse level of granularity. The proposed hybrid parallel processing approach achieves a near optimal speedup and provides a good trade-off between decoding time, latency and memory usage. On a 6 cores Xeon processor, the parallel SHVC decoder performs a real time decoding of 1600p60 video resolution

One Pass Quality Control and Low Complexity RDO in A Quadtree Based Scalable Image Coder

International audienceThis paper presents a joint quality control (QC) and rate distortion optimization (RDO) algorithm applied to a still image codec called Locally Adaptive Resolution (LAR). LAR supports scalability in resolution for both lossy and lossless coding and has low complexity. This algorithm is based on the study of the relationship between compression efficiency and relative parameters. The RDO model is proposed firstly to find suitable parameters. Relying on this optimization, relationships between the distortion of reconstructed image and quantization parameter can be described with a new linear model. This model is used for parametric configuration to control compression distortion. Experimental results show that this algorithm provides an effective solution for an efficient one pass codec with automatic parameters selection and accurate QC. This algorithm could be extended to codecs with similar functions, such as High Efficiency Video Coding (HEVC)

Implantation d'un algorithme de décomposition d'image sur une architecture multi-DSP à l'aide de SynDEx

L'objet de ce papier est de présenter les résultats de l'implantation d'un algorithme de décomposition d'image par des opérateurs morphologiques sur une architecture à base de processeurs TMS320C40 en utilisant l'environnement d'aide à l'implantation SynDEx. Ce dernier repose sur la méthodologie d'Adéquation Algorithme Architecture dont le but est de définir une implémentation optimisée de l'algorithme sur une architecture parallèle

EFFICIENT QUANTIZATION PARAMETER ESTIMATION IN HEVC BASED ON ρ-DOMAIN

International audienceThis paper proposes a quantization parameter estimation algorithm for HEVC CTU rate control. Several methods were proposed, mostly based on Lagrangian optimization combined with Laplacian distribution for transformed coeffi-cients. These methods are accurate but increase the encoder complexity. This paper provides an innovative reduced com-plexity algorithm based on a ρ-domain rate model. Indeed, for each CTU, the algorithm predicts encoding parameters based on co-located CTU. By combining it with Laplacian distri-bution for transformed coefficients, we obtain the dead-zone boundary for quantization and the related quantization pa-rameter. Experiments in the HEVC HM Reference Software show a good accuracy with only a 3% average bitrate error and no PSNR deterioration for random-access configuration

Modulation of Shoot Phosphate Level and Growth by PHOSPHATE1 Upstream Open Reading Frame.

Inorganic orthophosphate (Pi) is an essential nutrient for plant growth, and its availability strongly impacts crop yield. PHOSPHATE1 (PHO1) transfers Pi from root to shoot via Pi export into root xylem vessels. In this work, we demonstrate that an upstream open reading frame (uORF) present in the 5' untranslated region of the Arabidopsis (Arabidopsis thaliana) PHO1 inhibits its translation and influences Pi homeostasis. The presence of the uORF strongly inhibited the translation of a PHO1 5'UTR-luciferase construct in protoplasts. A point mutation removing the PHO1 uORF (ΔuORF) in transgenic Arabidopsis resulted in increased association of its mRNA with polysomes and led to higher PHO1 protein levels, independent of Pi availability. Interestingly, deletion of the uORF led to higher shoot Pi content and was associated with improved shoot growth under low external Pi supply and no deleterious effects under Pi-sufficient conditions. We further show that natural accessions lacking the PHO1 uORF exhibit higher PHO1 protein levels and shoot Pi content. Increased shoot Pi content was linked to the absence of the PHO1 uORF in a population of F2 segregants. We identified the PHO1 uORF in genomes of crops such as rice (Oryza sativa), maize (Zea mays), barley (Hordeum vulgare), and wheat (Triticum aesativum), and we verified the inhibitory effect of the rice PHO1 uORF on translation in protoplasts. Our work suggests that regulation of PHO1 expression via its uORF might be a genetic resource useful-both in natural populations and in the context of genome editing-toward improving plant growth under Pi-deficient conditions

Reducing childbirth-related intrusive memories and PTSD symptoms via a single-session behavioural intervention including a visuospatial task: A proof-of-principle study.

Intrusive memories (IMs) of traumatic events are a key symptom of posttraumatic stress disorder (PTSD), and contribute to its maintenance. This translational proof-of-principle study tested whether a single-session behavioural intervention reduced the number of childbirth-related IMs (CB-IMs) and childbirth-related PTSD (CB-PTSD) symptoms, in women traumatised by childbirth. The intervention was assumed to disrupt trauma memory reconsolidation. In this pre-post study, 18 participants, whose traumatic childbirth had occurred between seven months and 6.9 years before, received an intervention combining childbirth-related reminder cues (including the return to maternity unit) with a visuospatial task. They recorded their daily CB-IMs in the two weeks pre-intervention (diary 1), the two weeks post-intervention (diary 2; primary outcome), and in week 5 and 6 post-intervention (diary 3). CB-PTSD symptom severity was assessed five days pre-intervention and one month post-intervention. Compared to diary 1, 15/18 participants had ≥ 50% fewer CB-IMs in diary 2. The median (IQR) reduction of the number of CB-IMs was 81.89% (39.58%) in diary 2, and persisted in diary 3 (n = 17). At one month post-intervention, CB-PTSD symptom severity was reduced by ≥ 50% in 10/18 participants. Of the 8 participants with a CB-PTSD diagnosis pre-intervention, none met diagnostic criteria post-intervention. The intervention was rated as highly acceptable. The design limits the causal interpretation of observed improvements. This is the first time such a single-session behavioural intervention was tested for old and real-life single-event trauma. The promising results justify a randomized controlled trial, and may be a first step toward an innovative CB-PTSD treatment

4K real time video streaming with SHVC decoder and GPAC player

International audienceThis paper presents the first 4Kp30 end-to-end video streaming demonstration based on the upcoming Scalable High efficiency Video Coding (SHVC) standard. The optimized and parallel SHVC decoder is used under the GPAC player to decode and display in real time the received SHVC layers. The SHVC reference software model (SHM) is used to encode the 4K original video in two spatial scalability layers: the base layer at 1080p resolution and the enhancement layer at 2160p resolution. The SHVC bitstream is encapsulated with the GPAC multimedia library into MP4 file format. The GPAC player at the server side broadcasts the MP4 content in MPEG-2 TS. At the client side, the GPAC player receives the SHVC video packets which are decoded by the SHVC decoder and then rendered in real time by the player. The GPAC player provides an interactive interface enabling to switch between displaying the base and the enhancement layers