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

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

Codage d'objets de type VOP par représentation en régions auto-extractibles

Le nouveau standard multimédia Mpeg-4 traite aussi bien des aspects compression que de fonctionnalités de haut niveau telles que la manipulation d'objets. Notre approche propose un cadre unique permettant une compression efficace tout en offrant une segmentation à coût « quasi-nul » à travers le principe de représentation en régions auto-extractibles. Aussi montrons-nous ici que notre méthode peut constituer une alternative au mode classique de codage intra de Mpeg-4. En particulier, l'approche réussi à unifier le codage de la forme et de la texture d'un VOP

Color LAR codec : a color image representation and compression scheme based on local resolution adjustment and on self-extracting region representation

This LAR (Locally Adaptive Resolution) color image coding scheme yields to an efficient progressive compression with a better subjective quality than Jpeg2000. Additionally, it offers region functionalities for low bit rate coding and decoding. From highly compressed luminance, a region description, without contours encoding, can be obtained through a segmentation process performed at both coder and decoder. Considering color results, controlled chrominance components segmentation provides a better data consistency simultaneously with a low bit rate compression. As regions and their encoding are based on a same representation grid, enhancement of image quality can be global, or only restricted to a Region Of Interest.Cet article présente un schéma original de codage progressif d'images couleur apportant à la fois une efficacité en termes de compression (meilleure qualité subjective que Jpeg2000) et des fonctionnalités au niveau région à bas débits pour le codeur et le décodeur. À partir de l'image des luminances codée à bas débit par le codec LAR (Locally Adaptive Resolution), une description en régions, sans codage des contours, est obtenue à travers un procédé de segmentation effectué au codeur et au décodeur. Cette segmentation peut être contrôlée par les composantes chromatiques pour une meilleure cohérence du résultat d'un point de vue couleur. Un codage basé régions appliqué sur les images de chrominance produit alors une compression de ces composantes à très bas débit. Comme les régions et le codage de leur contenu partagent une même grille de représentation, l'amélioration de la qualité de l'image peut être globale, ou limitée à une zone d'intérêt

LOOP IIId of the HCV IRES is essential for the structural rearrangement of the 40S-HCV IRES complex

As obligatory intracellular parasites, viruses rely on cellular machines to complete their life cycle, and most importantly they recruit the host ribosomes to translate their mRNA. The Hepatitis C viral mRNA initiates translation by directly binding the 40S ribosomal subunit in such a way that the initiation codon is correctly positioned in the P site of the ribosome. Such a property is likely to be central for many viruses, therefore the description of host-pathogen interaction at the molecular level is instrumental to provide new therapeutic targets. In this study, we monitored the 40S ribosomal subunit and the viral RNA structural rearrangement induced upon the formation of the binary complex. We further took advantage of an IRES viral mutant mRNA deficient for translation to identify the interactions necessary to promote translation. Using a combination of structure probing in solution and molecular modeling we establish a whole atom model which appears to be very similar to the one obtained recently by cryoEM. Our model brings new information on the complex, and most importantly reveals some structural rearrangement within the ribosome. This study suggests that the formation of a 'kissing complex' between the viral RNA and the 18S ribosomal RNA locks the 40S ribosomal subunit in a conformation proficient for translation

Control of Cognate Sense mRNA Translation by cis-Natural Antisense RNAs.

Cis-Natural Antisense Transcripts (cis-NATs), which overlap protein coding genes and are transcribed from the opposite DNA strand, constitute an important group of noncoding RNAs. Whereas several examples of cis-NATs regulating the expression of their cognate sense gene are known, most cis-NATs function by altering the steady-state level or structure of mRNA via changes in transcription, mRNA stability, or splicing, and very few cases involve the regulation of sense mRNA translation. This study was designed to systematically search for cis-NATs influencing cognate sense mRNA translation in Arabidopsis (Arabidopsis thaliana). Establishment of a pipeline relying on sequencing of total polyA <sup>+</sup> and polysomal RNA from Arabidopsis grown under various conditions (i.e. nutrient deprivation and phytohormone treatments) allowed the identification of 14 cis-NATs whose expression correlated either positively or negatively with cognate sense mRNA translation. With use of a combination of cis-NAT stable over-expression in transgenic plants and transient expression in protoplasts, the impact of cis-NAT expression on mRNA translation was confirmed for 4 out of 5 tested cis-NAT:sense mRNA pairs. These results expand the number of cis-NATs known to regulate cognate sense mRNA translation and provide a foundation for future studies of their mode of action. Moreover, this study highlights the role of this class of noncoding RNAs in translation regulation

Single-session visuospatial task procedure to prevent childbirth-related posttraumatic stress disorder: a multicentre double-blind randomised controlled trial

Preventive evidence-based interventions for childbirth-related posttraumatic stress disorder (CB-PTSD) are lacking. Yet, 18.5% of women develop CB-PTSD symptoms following an unplanned caesarean section (UCS). This two-arm, multicentre, double-blind superiority trial tested the efficacy of an early single-session intervention including a visuospatial task on the prevention of maternal CB-PTSD symptoms. The intervention was delivered by trained maternity clinicians. Shortly after UCS, women were included if they gave birth to a live baby, provided consent, and perceived their childbirth as traumatic. Participants were randomly assigned to the intervention or attention-placebo group (allocation ratio 1:1). Assessments were done at birth, six weeks, and six months postpartum. Group differences in maternal CB-PTSD symptoms at six weeks (primary outcomes) and six months postpartum (secondary outcomes) were assessed with the self-report PTSD Checklist for DSM-5 (PCL-5) and by blinded research assessors with the Clinician-administered PTSD scale for DSM-5 (CAPS-5). Analysis was by intention-to-treat. The trial was prospectively registered (ClinicalTrials.gov, NCT03576586). Of the 2068 women assessed for eligibility, 166 were eligible and 146 were randomly assigned to the intervention (n = 74) or attention-placebo control group (n = 72). For the PCL-5, at six weeks, a marginally significant intervention effect was found on the total PCL-5 PTSD symptom count (β = -0.43, S.E. = 0.23, z = -1.88, p < 0.06), and on the intrusions (β = -0.73, S.E. = 0.38, z = -1.94, p < 0.0525) and arousal (β = -0.55, S.E. = 0.29, z = -1.92, p < 0.0552) clusters. At six months, a significant intervention effect on the total PCL-5 PTSD symptom count (β = -0.65, S.E. = 0.32, z = -2.04, p = 0.041, 95%CI[-1.27, -0.03]), on alterations in cognition and mood (β = -0.85, S.E. = 0.27, z = -3.15, p = 0.0016) and arousal (β = -0.56, S.E. = 0.26, z = -2.19, p < 0.0289, 95%CI[-1.07, -0.06]) clusters appeared. No group differences on the CAPS-5 emerged. Results provide evidence that this brief, single-session intervention carried out by trained clinicians can prevent the development of CB-PTSD symptoms up to six months postpartum

Datamama, bringing pregnancy research into the future: design, development, and evaluation of a citizen science pregnancy mobile application

Background: Pregnancy mobile applications (apps) have grown in popularity over the past decade, with some being used to promote study recruitment or health behaviors. However, no app serves as an all-in-one solution for collecting general data for research purposes and providing women with useful and desirable features. Aim: To create and develop a Swiss pregnancy mobile app as an innovative means to collect research data and provide users with reliable information. Methods: Determining the key features of the app involved a review of the literature and assessment of popular apps in the Swiss AppStore. A team of engineers developed the app, which includes a pregnancy timeline, questionnaires for data collection, medical and psychological articles and a checklist with appointment reminders. The content was written and reviewed by healthcare providers considered experts in the topics adressed. The questionnaires are distributed based on the user’s gestational age, by a chatbot. The project was authorized by the ethics commission in the canton of Vaud. An online survey of ten questions, advertised on Datamama’s home screen, was conducted to assess the users’ use of the app (27.11- 19.12.2022). Results: A review of 84 articles and 25 popular apps showed the need for a comprehensive pregnancy app. The development of Datamama took 2 years and included the creation of 70 medical and psychological articles and 29 questionnaires covering 300 unique variables. Six months after the launch, there were 800 users with a 73% average participation rate in the questionnaires. Sixty-five women completed the survey, with 70.8% using the app once to multiple times per week. The primary reason for using the app was to help research by answering the questionnaires, followed by access to reliable medical information. The reason most frequently ranked first for using the app was to help research by answering the questionnaires (42/65, 67% of women rated it first), followed by access to reliable medical information (34/65, 54% women rated it second). Women rated the information as clear, understandable, and interesting with a trust rating in data handling at 98.5%. The average grade for recommending the app was 8/10, with suggestions for increasing the amount of medical content and tailoring it based on gestational age. Conclusion: Datamama is the first pregnancy app to address the needs of both patients and researchers. Initial feedback from users was positive, highlighting future challenges for success. Future work will consist in improving the app, validating the data and use it to answer specific pregnancy-related research questions

Secretion of Hepatitis C Virus Envelope Glycoproteins Depends on Assembly of Apolipoprotein B Positive Lipoproteins

The density of circulating hepatitis C virus (HCV) particles in the blood of chronically infected patients is very heterogeneous. The very low density of some particles has been attributed to an association of the virus with apolipoprotein B (apoB) positive and triglyceride rich lipoproteins (TRL) likely resulting in hybrid lipoproteins known as lipo-viro-particles (LVP) containing the viral envelope glycoproteins E1 and E2, capsid and viral RNA. The specific infectivity of these particles has been shown to be higher than the infectivity of particles of higher density. The nature of the association of HCV particles with lipoproteins remains elusive and the role of apolipoproteins in the synthesis and assembly of the viral particles is unknown. The human intestinal Caco-2 cell line differentiates in vitro into polarized and apoB secreting cells during asymmetric culture on porous filters. By using this cell culture system, cells stably expressing E1 and E2 secreted the glycoproteins into the basal culture medium after one week of differentiation concomitantly with TRL secretion. Secreted glycoproteins were only detected in apoB containing density fractions. The E1–E2 and apoB containing particles were unique complexes bearing the envelope glycoproteins at their surface since apoB could be co-immunoprecipitated with E2-specific antibodies. Envelope protein secretion was reduced by inhibiting the lipidation of apoB with an inhibitor of the microsomal triglyceride transfer protein. HCV glycoproteins were similarly secreted in association with TRL from the human liver cell line HepG2 but not by Huh-7 and Huh-7.5 hepatoma cells that proved deficient for lipoprotein assembly. These data indicate that HCV envelope glycoproteins have the intrinsic capacity to utilize apoB synthesis and lipoprotein assembly machinery even in the absence of the other HCV proteins. A model for LVP assembly is proposed